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Sample records for nonpremixed ethylene jet

  1. Understanding and predicting soot generation in turbulent non-premixed jet flames.

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Hai (University of Southern California, Los Angeles, CA); Kook, Sanghoon; Doom, Jeffrey; Oefelein, Joseph Charles; Zhang, Jiayao; Shaddix, Christopher R.; Schefer, Robert W.; Pickett, Lyle M.

    2010-10-01

    This report documents the results of a project funded by DoD's Strategic Environmental Research and Development Program (SERDP) on the science behind development of predictive models for soot emission from gas turbine engines. Measurements of soot formation were performed in laminar flat premixed flames and turbulent non-premixed jet flames at 1 atm pressure and in turbulent liquid spray flames under representative conditions for takeoff in a gas turbine engine. The laminar flames and open jet flames used both ethylene and a prevaporized JP-8 surrogate fuel composed of n-dodecane and m-xylene. The pressurized turbulent jet flame measurements used the JP-8 surrogate fuel and compared its combustion and sooting characteristics to a world-average JP-8 fuel sample. The pressurized jet flame measurements demonstrated that the surrogate was representative of JP-8, with a somewhat higher tendency to soot formation. The premixed flame measurements revealed that flame temperature has a strong impact on the rate of soot nucleation and particle coagulation, but little sensitivity in the overall trends was found with different fuels. An extensive array of non-intrusive optical and laser-based measurements was performed in turbulent non-premixed jet flames established on specially designed piloted burners. Soot concentration data was collected throughout the flames, together with instantaneous images showing the relationship between soot and the OH radical and soot and PAH. A detailed chemical kinetic mechanism for ethylene combustion, including fuel-rich chemistry and benzene formation steps, was compiled, validated, and reduced. The reduced ethylene mechanism was incorporated into a high-fidelity LES code, together with a moment-based soot model and models for thermal radiation, to evaluate the ability of the chemistry and soot models to predict soot formation in the jet diffusion flame. The LES results highlight the importance of including an optically-thick radiation

  2. Scalar filtered mass density functions in nonpremixed turbulent jet flames

    Energy Technology Data Exchange (ETDEWEB)

    Drozda, Tomasz G.; Wang, Guanghua; Sankaran, Vaidyanathan; Mayo, Jackson R.; Oefelein, Joseph C.; Barlow, Robert S. [Combustion Research Facility, Sandia National Laboratories, P.O. Box 969, MS 9051, Livermore, CA 94551 (United States)

    2008-10-15

    Filtered mass density functions (FMDFs) of mixture fraction and temperature are studied by analyzing experimental data obtained from one-dimensional Raman/Rayleigh/LIF measurements of nonpremixed CH{sub 4}/H{sub 2}/N{sub 2} turbulent jet flames at Reynolds numbers of 15,200 and 22,800 (DLR-A and -B). The experimentally determined FMDFs are conditioned on the Favre filtered values of the mixture fraction and its variance. Filter widths are selected as fixed multiples of the experimentally determined dissipation length scale at each measurement location. One-dimensional filtering using a top-hat filter is performed to obtain the filtered variables used for conditioning. The FMDFs are obtained by binning the mass and filter kernel weighted samples. Emphasis is placed on the shapes of the FMDFs in the fuel-rich, fuel-lean, and stoichiometric intervals for the Favre filtered mixture fraction, and low, medium, and high values for the Favre filtered mixture fraction variance. It is found that the FMDFs of mixture fraction are unimodal in samples with low mixture fraction variance and bimodal in samples with high variance. However, the FMDFs of mixture fraction at the smallest filter size studied are unimodal for all values of the variance. The FMDFs of temperature are unimodal in samples with low mixture fraction variance, and either unimodal or bimodal, depending on the mixture fraction mean, in samples with high variance. The influence of the filter size and the jet Reynolds number on the FMDFs is also considered. (author)

  3. Effects of Large Polycyclic Aromatic Hydrocarbons on the Soot Formation in Ethylene-Air Nonpremixed Flames

    KAUST Repository

    Prabhu, S.

    2015-03-30

    This study presents updated comprehensive gas-phase kinetic mechanism and aerosol models to predict soot formation characteristics in ethylene-air nonpremixed flames. A main objective is to investigate the sensitivity of the soot formation rate to various chemical pathways for large polycyclic aromatic hydrocarbons (PAH). In this study, the detailed chemical mechanism was reduced from 397 to 99 species using directed relation graph (DRG) and sensitivity analysis. The method of moments with interpolative closure (MOMIC) was employed for the soot aerosol model. Counterflow nonpremixed flames of pure ethylene at low strain rate sooting conditions are considered, for which the sensitivity of soot formation characteristics with respect to hetrogeneous nucleation is investigated. Results show that higher PAH concentrations result in higher soot nucleation rate, and that the average size of the particles are in good agreement with experimental results. It is found that the nucleation processes (i.e., soot inception) from higher PAH precursors, coronene in particular, is critical for accurate prediction of the overall soot formation.

  4. Flame propagation and counterflow nonpremixed ignition of mixtures of methane and ethylene

    Energy Technology Data Exchange (ETDEWEB)

    Liu, W.; Kelley, A.P.; Law, C.K. [Department of Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544 (United States)

    2010-05-15

    The ignition temperature of nitrogen-diluted mixtures of methane and ethylene counterflowing against heated air was measured up to five atmospheres. In addition, the stretch-corrected laminar flame speeds of mixtures of air, methane and ethylene were determined from outwardly-propagating spherical flames up to 10 atmospheres, for extensive range of the lean-to-rich equivalence ratio. These experimental data, relevant to low- to moderately-high-temperature ignition chemistry and high-temperature flame chemistry, respectively, were subsequently compared with calculations using two detailed kinetic mechanisms. A chemical explosive mode analysis (CEMA) was then conducted to identify the dominant ignition chemistry and the role of ethylene addition in facilitating nonpremixed ignition. Furthermore, the hierarchical structure of the associated oxidation kinetics was examined by comparing the sizes and constituents of the skeletal mechanisms of the pure fuels and their mixtures, derived using the method of directed relation graph (DRG). The skeletal mechanism was further reduced by time-scale analysis, leading to a 24-species reduced mechanism from the detailed mechanism of USC Mech II, validated within the parameter space of the conducted experiments. (author)

  5. Soot reduction under DC electric fields in counterflow non-premixed laminar ethylene flames

    KAUST Repository

    Park, Daegeun

    2014-04-23

    The effects of DC electric fields on non-premixed ethylene flames in a counterflow burner were studied experimentally with a focus on the reduction of soot particles. The experiment was conducted by connecting a high voltage terminal and a ground terminal to a lower (fuel) and upper (oxidizer) nozzle, respectively. We applied direct current (DC) potentials in a range of -5 kV < Vdc < 5 kV. Uniform electric fields were then generated in the gap between the two nozzles. The experimental conditions were selected to cover both soot formation (SF) and soot formation oxidation (SFO) flames. The flames subjected to the negative electric fields moved toward the fuel nozzle because of an ionic wind due to the Lorentz force acting on the positive ions in the flames. In addition, the yellow luminosity significantly decreased, indicating changes in the sooting characteristics. To analyze the sooting characteristics under the electric fields, planar laser induced incandescence (PLII) and fluorescence (PLIF) techniques were used to visualize the soot, polycyclic aromatic hydrocarbons (PAHs), and OH radicals. The sooting limits in terms of the fuel and oxygen mole fractions were measured. No substantial soot formation due to the effects of the DC electric fields for the tested range of voltages and reactant mole fractions could be identified. The detailed flame behaviors and sooting characteristics under the DC electric fields are discussed. Copyright © Taylor & Francis Group, LLC.

  6. Dynamics of flow-soot interaction in wrinkled non-premixed ethylene-air flames

    Science.gov (United States)

    Arias, Paul G.; Lecoustre, Vivien R.; Roy, Somesh; Luo, Zhaoyu; Haworth, Daniel C.; Lu, Tianfeng; Trouvé, Arnaud; Im, Hong G.

    2015-09-01

    A two-dimensional simulation of a non-premixed ethylene-air flame was conducted by employing a detailed gas-phase reaction mechanism considering polycyclic aromatic hydrocarbons, an aerosol-dynamics-based soot model using a method of moments with interpolative closure, and a grey gas and soot radiation model using the discrete transfer method. Interaction of the sooting flame with a prescribed decaying random velocity field was investigated, with a primary interest in the effects of velocity fluctuations on the flame structure and the associated soot formation process for a fuel-strip configuration and a composition with mature soot growth. The temporally evolving simulation revealed a multi-layered soot formation process within the flame, at a level of detail not properly described by previous studies based on simplified soot models utilizing acetylene or naphthalene precursors for initial soot inception. The overall effect of the flame topology on the soot formation was found to be consistent with previous experimental studies, while a unique behaviour of localised strong oxidation was also noted. The imposed velocity fluctuations led to an increase of the scalar dissipation rate in the sooting zone, causing a net suppression in the soot production rate. Considering the complex structure of the soot formation layer, the effects of the imposed fluctuations vary depending on the individual soot reactions. For the conditions under study, the soot oxidation reaction was identified as the most sensitive to the fluctuations and was mainly responsible for the local suppression of the net soot production.

  7. Soot Particle Size Distribution Functions in a Turbulent Non-Premixed Ethylene-Nitrogen Flame

    KAUST Repository

    Boyette, Wesley

    2017-02-21

    A scanning mobility particle sizer with a nano differential mobility analyzer was used to measure nanoparticle size distribution functions in a turbulent non-premixed flame. The burner utilizes a premixed pilot flame which anchors a C2H4/N2 (35/65) central jet with ReD = 20,000. Nanoparticles in the flame were sampled through a N2-filled tube with a 500- μm orifice. Previous studies have shown that insufficient dilution of the nanoparticles can lead to coagulation in the sampling line and skewed particle size distribution functions. A system of mass flow controllers and valves were used to vary the dilution ratio. Single-stage and two-stage dilution systems were investigated. A parametric study on the effect of the dilution ratio on the observed particle size distribution function indicates that particle coagulation in the sampling line can be eliminated using a two-stage dilution process. Carbonaceous nanoparticle (soot) concentration particle size distribution functions along the flame centerline at multiple heights in the flame are presented. The resulting distributions reveal a pattern of increasing mean particle diameters as the distance from the nozzle along the centerline increases.

  8. Blow-out of nonpremixed turbulent jet flames at sub-atmospheric pressures

    KAUST Repository

    Wang, Qiang

    2016-12-09

    Blow-out limits of nonpremixed turbulent jet flames in quiescent air at sub-atmospheric pressures (50–100 kPa) were studied experimentally using propane fuel with nozzle diameters ranging 0.8–4 mm. Results showed that the fuel jet velocity at blow-out limit increased with increasing ambient pressure and nozzle diameter. A Damköhler (Da) number based model was adopted, defined as the ratio of characteristic mixing time and characteristic reaction time, to include the effect of pressure considering the variations in laminar burning velocity and thermal diffusivity with pressure. The critical lift-off height at blow-out, representing a characteristic length scale for mixing, had a linear relationship with the theoretically predicted stoichiometric location along the jet axis, which had a weak dependence on ambient pressure. The characteristic mixing time (critical lift-off height divided by jet velocity) adjusted to the characteristic reaction time such that the critical Damköhler at blow-out conditions maintained a constant value when varying the ambient pressure.

  9. A NEW DOUBLE-SLIT CURVED WALL-JET (CWJ) BURNER FOR STABILIZING TURBULENT PREMIXED AND NON-PREMIXED FLAMES

    KAUST Repository

    Mansour, Morkous S.

    2015-06-30

    A novel double-slit curved wall-jet (CWJ) burner was proposed and employed, which utilizes the Coanda effect by supplying fuel and air as annular-inward jets over a curved surface. We investigated the stabilization characteristics and structure of methane/air, and propane/air turbulent premixed and non-premixed flames with varying global equivalence ratio, , and Reynolds number, Re. Simultaneous time-resolved measurements of particle image velocimetry and planar laser-induced fluorescence of OH radicals were conducted. The burner showed potential for stable operation for methane flames with relatively large fuel loading and overall rich conditions. These have a non-sooting nature. However, propane flames exhibit stable mode for a wider range of equivalence ratio and Re. Mixing characteristics in the cold flow of non-premixed cases were first examined using acetone fluorescence technique, indicating substantial transport between the fuel and air by exhibiting appreciable premixing conditions.PIV measurements revealed that velocity gradients in the shear layers at the boundaries of the annularjets generate the turbulence, enhanced with the collisions in the interaction jet, IJ,region. Turbulent mean and rms velocities were influenced significantly by Re and high rms turbulent velocities are generated within the recirculation zone improving the flame stabilization in this burner.Premixed and non-premixed flames with high equivalence ratio were found to be more resistant to local extinction and exhibited a more corrugated and folded nature, particularly at high Re. For flames with low equivalence ratio, the processes of local quenching at IJ region and of re-ignition within merged jet region maintained these flames further downstream particularly for non-premixed methane flame, revealing a strong intermittency.

  10. Electric fields effect on liftoff and blowoff of nonpremixed laminar jet flames in a coflow

    KAUST Repository

    Kim, Minkuk

    2010-01-01

    The stabilization characteristics of liftoff and blowoff in nonpremixed laminar jet flames in a coflow have been investigated experimentally for propane fuel by applying AC and DC electric fields to the fuel nozzle with a single-electrode configuration. The liftoff and blowoff velocities have been measured by varying the applied voltage and frequency of AC and the voltage and the polarity of DC. The result showed that the AC electric fields extended the stabilization regime of nozzle-attached flame in terms of jet velocity. As the applied AC voltage increased, the nozzle-attached flame was maintained even over the blowout velocity without having electric fields. In such a case, a blowoff occurred directly without experiencing a lifted flame. While for the DC cases, the influence on liftoff was minimal. There existed three different regimes depending on the applied AC voltage. In the low voltage regime, the nozzle-detachment velocity of either liftoff or blowoff increased linearly with the applied voltage, while nonlinearly with the AC frequency. In the intermediate voltage regime, the detachment velocity decreased with the applied voltage and reasonably independent of the AC frequency. At the high voltage regime, the detachment was significantly influenced by the generation of discharges. © 2009 The Combustion Institute.

  11. Imaging Fourier-transform spectrometer measurements of a turbulent nonpremixed jet flame.

    Science.gov (United States)

    Harley, Jacob L; Rankin, Brent A; Blunck, David L; Gore, Jay P; Gross, Kevin C

    2014-04-15

    This work presents recent measurements of a CH4/H2/N2 turbulent nonpremixed jet flame using an imaging Fourier-transform spectrometer (IFTS). Spatially resolved (128×192 pixels, 0.72  mm/pixel) mean radiance spectra were collected between 1800  cm(-1)≤ν˜≤4500  cm(-1) (2.22  μm≤λ≤5.55  μm) at moderate spectral resolution (δν=16  cm(-1), δλ=20  nm) spanning the visible flame. Higher spectral-resolution measurements (δν=0.25  cm(-1), δλ=0.3  nm) were also captured on a smaller window (8×192) at 20, 40, and 60 diameters above the jet exit and reveal the rotational fine structure associated with various vibrational transitions in CH4, CO2, CO, and H2O. These new imaging measurements compare favorably with existing spectra acquired at select flame locations, demonstrating the capability of IFTS for turbulent combustion studies.

  12. Effects of DME mixing on number density and size properties of soot particles in counterflow non-premixed ethylene flames

    KAUST Repository

    Choi, J. H.

    2015-05-01

    In order to investigate the effect of DME mixing on the number density and size of soot particles, DME was mixed in a counter flow non-premixed ethylene flame with mixture ratios of 5%, 14% and 30%. A laser extinction/scattering technique has been adopted to measure the volume fraction, number density, and mean size of soot particles. The experimental results showed that the highest soot concentrations were observed for flames with mixture ratios of 5% and 14%; however, for a mixture ratio of 30% the soot concentration decreased. Numerical results showed that the concentrations of propargyl radicals (C3H3) at the 5% and 14% ratios were higher than those measured in the ethylene-based flame, and the production of benzene (C6H6) in the 5% and 14% DME mixture flames was also increased. This indicates the crucial role of propargyl in benzene ring formation. These reactions generally become stronger with increased DME mixing, except for A1- + H2 → A1 + H (-R554) and n-C4H5 + C2H2 → A1 + H (R542). Therefore, it is indicated that adding DME to ethylene flames promotes benzene ring formation. Note that although the maximum C6H6 concentration is largest in the 30% DME mixing flame, the soot volume fraction is smaller than those for the 5% and 14% mixture ratios. This is because the local C6H6 concentration decreases in the relatively low temperature region in the fuel side where soot growth occurs. © 2015, The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg.

  13. Blow-out limits of nonpremixed turbulent jet flames in a cross flow at atmospheric and sub-atmospheric pressures

    KAUST Repository

    Wang, Qiang

    2015-07-22

    The blow-out limits of nonpremixed turbulent jet flames in cross flows were studied, especially concerning the effect of ambient pressure, by conducting experiments at atmospheric and sub-atmospheric pressures. The combined effects of air flow and pressure were investigated by a series of experiments conducted in an especially built wind tunnel in Lhasa, a city on the Tibetan plateau where the altitude is 3650 m and the atmospheric pressure condition is naturally low (64 kPa). These results were compared with results obtained from a wind tunnel at standard atmospheric pressure (100 kPa) in Hefei city (altitude 50 m). The size of the fuel nozzles used in the experiments ranged from 3 to 8 mm in diameter and propane was used as the fuel. It was found that the blow-out limit of the air speed of the cross flow first increased (“cross flow dominant” regime) and then decreased (“fuel jet dominant” regime) as the fuel jet velocity increased in both pressures; however, the blow-out limit of the air speed of the cross flow was much lower at sub-atmospheric pressure than that at standard atmospheric pressure whereas the domain of the blow-out limit curve (in a plot of the air speed of the cross flow versus the fuel jet velocity) shrank as the pressure decreased. A theoretical model was developed to characterize the blow-out limit of nonpremixed jet flames in a cross flow based on a Damköhler number, defined as the ratio between the mixing time and the characteristic reaction time. A satisfactory correlation was obtained at relative strong cross flow conditions (“cross flow dominant” regime) that included the effects of the air speed of the cross flow, fuel jet velocity, nozzle diameter and pressure.

  14. Direct numerical simulations of non-premixed ethylene-air flames: Local flame extinction criterion

    KAUST Repository

    Lecoustre, Vivien R.

    2014-11-01

    Direct Numerical Simulations (DNS) of ethylene/air diffusion flame extinctions in decaying two-dimensional turbulence were performed. A Damköhler-number-based flame extinction criterion as provided by classical large activation energy asymptotic (AEA) theory is assessed for its validity in predicting flame extinction and compared to one based on Chemical Explosive Mode Analysis (CEMA) of the detailed chemistry. The DNS code solves compressible flow conservation equations using high order finite difference and explicit time integration schemes. The ethylene/air chemistry is simulated with a reduced mechanism that is generated based on the directed relation graph (DRG) based methods along with stiffness removal. The numerical configuration is an ethylene fuel strip embedded in ambient air and exposed to a prescribed decaying turbulent flow field. The emphasis of this study is on the several flame extinction events observed in contrived parametric simulations. A modified viscosity and changing pressure (MVCP) scheme was adopted in order to artificially manipulate the probability of flame extinction. Using MVCP, pressure was changed from the baseline case of 1 atm to 0.1 and 10 atm. In the high pressure MVCP case, the simulated flame is extinction-free, whereas in the low pressure MVCP case, the simulated flame features frequent extinction events and is close to global extinction. Results show that, despite its relative simplicity and provided that the global flame activation temperature is correctly calibrated, the AEA-based flame extinction criterion can accurately predict the simulated flame extinction events. It is also found that the AEA-based criterion provides predictions of flame extinction that are consistent with those provided by a CEMA-based criterion. This study supports the validity of a simple Damköhler-number-based criterion to predict flame extinction in engineering-level CFD models. © 2014 The Combustion Institute.

  15. Application of Dielectric-Barrier Discharge to the Stabilization of Lifted Non-Premixed Methane/Air Jet Flames

    Science.gov (United States)

    Liao, Ying-Hao; Zhao, Xiang-Hong

    2016-11-01

    Recent studies have shown that the application of non-thermal plasma is a promising way to enhance the flame stabilization and combustion efficiency. The present study experimentally investigates the effect of a dielectric-barrier discharge (DBD) on the stabilization of lifted non-premixed methane/air jet flames. The jet flame with co-annular DBD is produced by a co-flow burner and has a Reynolds number of Re = 2500, 5000, 7000, and 9000. The application of DBD is seen to have an impact on the flame lift-off height, and the degree of impact is subject to flow conditions (such as Reynolds number and co-flow velocity) and plasma power. In general, the enhancement of flame stabilization, indicated by the decrease in lift-off height, is most evident at low Reynolds number and co-flow velocity. For flames with a Reynolds number less than Re = 5000, flames are attached to the nozzle regardless of the co-flow velocity and plasma power; at Re = 5000, flames are often intermittently attached. The enhancement is not that significant at high Reynolds number and co-flow velocity at least for the plasma power employed in the current study. A slight increase in plasma power leads to enhanced flame stabilization.

  16. Formation, growth, and transport of soot in a three-dimensional turbulent non-premixed jet flame

    KAUST Repository

    Attili, Antonio

    2014-07-01

    The formation, growth, and transport of soot is investigated via large scale numerical simulation in a three-dimensional turbulent non-premixed n-heptane/air jet flame at a jet Reynolds number of 15,000. For the first time, a detailed chemical mechanism, which includes the soot precursor naphthalene and a high-order method of moments are employed in a three-dimensional simulation of a turbulent sooting flame. The results are used to discuss the interaction of turbulence, chemistry, and the formation of soot. Compared to temperature and other species controlled by oxidation chemistry, naphthalene is found to be affected more significantly by the scalar dissipation rate. While the mixture fraction and temperature fields show fairly smooth spatial and temporal variations, the sensitivity of naphthalene to turbulent mixing causes large inhomogeneities in the precursor fields, which in turn generate even stronger intermittency in the soot fields. A strong correlation is apparent between soot number density and the concentration of naphthalene. On the contrary, while soot mass fraction is usually large where naphthalene is present, pockets of fluid with large soot mass are also frequent in regions with very low naphthalene mass fraction values. From the analysis of Lagrangian statistics, it is shown that soot nucleates and grows mainly in a layer close to the flame and spreads on the rich side of the flame due to the fluctuating mixing field, resulting in more than half of the total soot mass being located at mixture fractions larger than 0.6. Only a small fraction of soot is transported towards the flame and is completely oxidized in the vicinity of the stoichiometric surface. These results show the leading order effects of turbulent mixing in controlling the dynamics of soot in turbulent flames. Finally, given the difficulties in obtaining quantitative data in experiments of turbulent sooting flames, this simulation provides valuable data to guide the development of

  17. The effects of buoyancy on turbulent nonpremixed jet flames in crossflow

    Science.gov (United States)

    Boxx, Isaac G.

    An experimental research study was conducted to investigate what effect buoyancy had on the mean and instantaneous flow-field characteristics of turbulent jet-flames in crossflow (JFICF). The study used an experimental technique wherein a series of normal-gravity, hydrogen-diluted propane JFICF were compared with otherwise identical ones in low-gravity. Experiments were conducted at the University of Texas Drop Tower Facility, a new microgravity science laboratory built for this study at the University of Texas at Austin. Two different diagnostic techniques were employed, high frame-rate digital cinematographic imaging and planar laser Mie scattering (PLMS). The flame-luminosity imaging revealed significant elongation and distortion of the large-scale luminous structure of the JFICF. This was seen to affect the flametip oscillation and burnout characteristics. Mean and root-mean-square (RMS) images of flame-luminosity were computed from the flame-luminosity image sequences. These were used to compare visible flame-shapes, flame chord-lengths and jet centerline-trajectories of the normal- and low-gravity flames. In all cases the jet-centerline penetration and mean luminous flame-width were seen to increase with decreasing buoyancy. The jet-centerline trajectories for the normal-gravity flames were seen to behave differently to those of the low-gravity flames. This difference led to the conclusion that the jet transitions from a momentum-dominated forced convection limit to a buoyancy-influenced regime when it reaches xiC ≈ 3, where xiC is the Becker and Yamazaki (1978) buoyancy parameter based on local flame chord-length. The mean luminous flame-lengths showed little sensitivity to buoyancy or momentum flux ratio. Consistent with the flame-luminosity imaging experiments, comparison of the instantaneous PLMS flow-visualization images revealed substantial buoyancy-induced elongation and distortion of the large-scale shear-layer vortices in the flow. This effect

  18. CONDITIONAL FLOW STATISTICS AND ALIGNMENT OF PRINCIPAL STRAIN RATES, VORTICITY, AND SCALAR GRADIENTS IN A TURBULENT NONPREMIXED JET FLAME

    KAUST Repository

    Attili, Antonio

    2015-06-30

    The alignment of vorticity and gradients of conserved and reactive scalars with the eigenvectors of the strain rate tensor (i.e., the principal strains) is investigated in a direct numerical simulation of a turbulent nonpremixed flame achieving a Taylor’s scale Reynolds number in the range 100≤Reλ≤150 (Attili et al. Comb. Flame, 161, 2014). The vorticity vector displays a pronounced tendency to align with the direction of the intermediate strain. These alignment statistics are in almost perfect agreement with those in homogeneous isotropic turbulence (Ashurst et al. Physics of Fluids 30, 1987) and differ significantly from the results obtained in other nonpremixed flames in which vorticity alignment with the most extensive strain was observed (Boratavet al. Physics of Fluids 8, 1996). The gradients of conserved and reactive scalars align with the most compressive strain. It is worth noting that conditioning on the local values of the mixture fraction, or equivalently conditioning on the distance from the flame sheet, does not affect the statistics. Our results suggest that turbulence overshadows the effects of heat release and chemical reactions. This may be due to the larger Reynolds number achieved in the present study compared to that in previous works.

  19. Numerical study of laminar nonpremixed methane flames in coflow jets: Autoignited lifted flames with tribrachial edges and MILD combustion at elevated temperatures

    KAUST Repository

    M. Al-Noman, Saeed

    2016-07-07

    Autoignition characteristics of laminar nonpremixed methane jet flames in high-temperature coflow air are studied numerically. Several flame configurations are investigated by varying the initial temperature and fuel mole fraction. At a relatively low initial temperature, a non-autoignited nozzle-attached flame is simulated at relatively low jet velocity. When the initial temperature is higher than that required for autoignition, two regimes are investigated: an autoignited lifted flame with tribrachial edge structure and an autoignited lifted flame with Mild combustion. The autoignited lifted flame with tribrachial edge exhibited three branches: lean and rich premixed flame wings and a trailing diffusion flame. Characteristics of kinetic structure for autoignited lifted flames are discussed based on the kinetic structures of homogeneous autoignition and flame propagation of stoichiometric mixture. Results showed that a transition from autoignition to flame propagation modes occurs for reasonably stoichiometric mixtures. The autoignited lifted flame with Mild combustion occurs when methane fuel is highly diluted with nitrogen. The kinetic structure analysis shows that the characteristics of Mild combustion can be treated as an autoignited lean premixed lifted flame. Transition behavior from Mild combustion to nozzle-attached flame was investigated by increasing the fuel mole fraction. As the maximum flame temperature increases with decreasing liftoff height, the kinetic structure showed a transition behavior from autoignition to flame propagation of a lean premixed flame. © 2016 The Combustion Institute

  20. Turbulent Non-Premixed Flames Stabilized on Double-Slit Curved Wall-Jet Burner with Simultaneous OH-Planar Laser-Induced Fluorescence and Particle Image Velocimetry Measurements

    KAUST Repository

    Mansour, Morkous S.

    2015-04-29

    A double-slit curved wall-jet (CWJ) burner utilizing a Coanda effect by supplying fuel and air as annular-inward jets over a curved surface was employed to investigate the stabilization characteristics and structure of propane/air turbulent non-premixed flames with varying global equivalence ratio and Reynolds number. Simultaneous time-resolved measurements of particle image velocimetry (PIV) and planar laser-induced fluorescence (PLIF) of OH radicals were conducted. The burner showed a potential of stable and non-sooting operation for relatively large fuel loading and overall rich conditions. Mixing characteristics in cold flow were first examined using an acetone fluorescence technique, indicating substantial transport between the fuel and air by exhibiting appreciable premixing conditions. PIV measurements revealed that the flow field consisted of a wall-jet region leading to a recirculation zone through flow separation, an interaction jet region resulting from the collision of annular-inward jets, followed by a merged-jet region. The flames were stabilized in the recirculation zone and, in extreme cases, only a small flame seed remained in the recirculation zone. Together with the collision of the slit jets in the interaction jet region, the velocity gradients in the shear layers at the boundaries of the annular jets generate the turbulence. Turbulent mean and rms velocities were influenced by the presence of the flame, particularly in the recirculation zone. Flames with a high equivalence ratio were found to be more resistant to local extinction and exhibited a more corrugated and folded nature, particularly at high Reynolds numbers. For flames with a low equivalence ratio, local quenching and re-ignition processes maintained flames in the merged jet region, revealing a strong intermittency, which was substantiated by the increased principal strain rates for these flames. © 2015 Taylor & Francis Group, LLC.

  1. Unsteady Extinction of Opposed Jet Ethylene/Methane HIFiRE Surrogate Fuel Mixtures vs Air

    Science.gov (United States)

    Vaden, Sarah N.; Debes, Rachel L.; Lash, E. Lara; Burk, Rachel S.; Boyd, C. Merritt; Wilson, Lloyd G.; Pellett, Gerald L.

    2009-01-01

    A unique idealized study of the subject fuel vs. air systems was conducted using an Oscillatory-input Opposed Jet Burner (OOJB) system and a newly refined analysis. Extensive dynamic-extinction measurements were obtained on unanchored (free-floating) laminar Counter Flow Diffusion Flames (CFDFs) at 1-atm, stabilized by steady input velocities (e.g., U(sub air)) and perturbed by superimposed in-phase sinusoidal velocity inputs at fuel and air nozzle exits. Ethylene (C2H4) and methane (CH4), and intermediate 64/36 and 15/85 molar percent mixtures were studied. The latter gaseous surrogates were chosen earlier to mimic ignition and respective steady Flame Strengths (FS = U(sub air)) of vaporized and cracked, and un-cracked, JP-7 "like" kerosene for a Hypersonic International Flight Research Experimentation (HIFiRE) scramjet. For steady idealized flameholding, the 100% C2H4 flame is respectively approx. 1.3 and approx.2.7 times stronger than a 64/36 mix and CH4; but is still 12.0 times weaker than a 100% H2-air flame. Limited Hot-Wire (HW) measurements of velocity oscillations at convergent-nozzle exits, and more extensive Probe Microphone (PM) measurements of acoustic pressures, were used to normalize Dynamic FSs, which decayed linearly with pk/pk U(sub air) (velocity magnitude, HW), and also pk/pk P (pressure magnitude, PM). Thus Dynamic Flame Weakening (DFW) is defined as % decrease in FS per Pascal of pk/pk P oscillation, namely, DFW = -100 d(U(sub air)/U(sub air),0Hz)/d(pkpk P). Key findings are: (1) Ethylene flames are uniquely strong and resilient to extinction by oscillating inflows below 150 Hz; (2) Methane flames are uniquely weak; (3) Ethylene / methane surrogate flames are disproportionately strong with respect to ethylene content; and (4) Flame weakening is consistent with limited published results on forced unsteady CFDFs. Thus from 0 to approx. 10 Hz and slightly higher, lagging diffusive responses of key species led to progressive phase lags (relative

  2. Numerical Study of Unsteady Properties of Ethylene/Air Turbulent Jet Diffusion Flame with Detached Eddy Simulation

    Science.gov (United States)

    Ma, Sugang; Zhong, Fengquan; Zhang, Xinyu

    2016-12-01

    In this paper, unsteady process of ignition and combustion of turbulent plane-jet diffusion flame of ethylene/air is numerically simulated with detached eddy simulation (DES) and a reduced kinetic mechanism of ethylene. The kinetic mechanism consisting of 25 species and 131 steps is reduced from a 25 species/131 steps detailed mechanism via the method of error-propagation-based directed relation graph (DRGEP). The DES results of averaged temperature profiles at varied downstream locations are compared with the DNS results of Yoo et al. and satisfactory agreement between them is found. Ignition and combustion of ethylene plane-jet diffusion flame is simulated and dynamic changes of temperature field and OH radical are obtained. The present numerical study shows that DES method with a qualified reduced mechanism of hydrocarbon fuels can effectively simulate temporal and spatial evolution of ignition and combustion process.

  3. Autoignition and flame stabilisation processes in turbulent non-premixed hot coflow flames

    NARCIS (Netherlands)

    Oldenhof , E.

    2012-01-01

    This dissertation examines stabilisation processes in turbulent non-premixed jet flames, created by injecting gaseous fuel into a co-flowing stream of hot, low-oxygen combustion products. Being able to predict whether and how a flame achieves stable and reliable combustion is a matter of great pract

  4. Nitric Oxide and Oxygen Air-Contamination Effects on Extinction Limits of Non-Premixed Hydrocarbon-Air Flames for a HIFiRE Scramjet

    Science.gov (United States)

    Pellett, Gerald L.; Dawson, Lucy C.; Vaden, Sarah N.; Wilson, Lloyd G.

    2009-01-01

    Unique nitric oxide (NO) and oxygen air-contamination effects on the extinction Flame Strength (FS) of non-premixed hydrocarbon (HC) vs. air flames are characterized for 7 gaseous HCs, using a new idealized 9.3 mm straight-tube Opposed Jet Burner (OJB) at 1 atm. FS represents a laminar strain-induced extinction limit based on cross-section-average air jet velocity, Uair, that sustains combustion of a counter jet of gaseous fuel just before extinction. Besides ethane, propane, butane, and propylene, the HCs include ethylene, methane, and a 64 mole-% ethylene / 36 % methane mixture, the writer s previously recommended gaseous surrogate fuel for HIFiRE scramjet tests. The HC vs. clean air part of the work is an extension of a May 2008 JANNAF paper that characterized surrogates for the HIFiRE project that should mimic the flameholding of reformed (thermally- or catalytically-cracked) endothermic JP-like fuels. The new FS data for 7 HCs vs. clean air are thus consolidated with the previously validated data, normalized to absolute (local) axial-input strain rates, and co-plotted on a dual kinetically dominated reactivity scale. Excellent agreement with the prior data is obtained for all 7 fuels. Detailed comparisons are also made with recently published (Univ. Va) numerical results for ethylene extinction. A 2009-revised ethylene kinetic model (Univ. Southern Cal) led to predicted limits within approx. 5 % (compared to 45 %, earlier) of this writer s 2008 (and present) ethylene FSs, and also with recent independent data (Univ. Va) obtained on a new OJB system. These +/- 5 % agreements, and a hoped-for "near-identically-performing" reduced kinetics model, would greatly enhance the capability for accurate numerical simulations of surrogate HC flameholding in scramjets. The measured air-contamination effects on normalized FS extinction limits are projected to assess ongoing Arc-Heater-induced "facility test effects" of NO production (e.g., 3 mole-%) and resultant oxygen

  5. Mixing Model Performance in Non-Premixed Turbulent Combustion

    Science.gov (United States)

    Pope, Stephen B.; Ren, Zhuyin

    2002-11-01

    In order to shed light on their qualitative and quantitative performance, three different turbulent mixing models are studied in application to non-premixed turbulent combustion. In previous works, PDF model calculations with detailed kinetics have been shown to agree well with experimental data for non-premixed piloted jet flames. The calculations from two different groups using different descriptions of the chemistry and turbulent mixing are capable of producing the correct levels of local extinction and reignition. The success of these calculations raises several questions, since it is not clear that the mixing models used contain an adequate description of the processes involved. To address these questions, three mixing models (IEM, modified Curl and EMST) are applied to a partially-stirred reactor burning hydrogen in air. The parameters varied are the residence time and the mixing time scale. For small relative values of the mixing time scale (approaching the perfectly-stirred limit) the models yield the same extinction behavior. But for larger values, the behavior is distictly different, with EMST being must resistant to extinction.

  6. Hydroxyl time series and recirculation in turbulent nonpremixed swirling flames

    Energy Technology Data Exchange (ETDEWEB)

    Guttenfelder, Walter A.; Laurendeau, Normand M.; Ji, Jun; King, Galen B.; Gore, Jay P. [School of Mechanical Engineering, Purdue University, West Lafayette, IN 47907-1288 (United States); Renfro, Michael W. [Department of Mechanical Engineering, University of Connecticut, Storrs, CT 06269-3139 (United States)

    2006-10-15

    Time-series measurements of OH, as related to accompanying flow structures, are reported using picosecond time-resolved laser-induced fluorescence (PITLIF) and particle-imaging velocimetry (PIV) for turbulent, swirling, nonpremixed methane-air flames. The [OH] data portray a primary reaction zone surrounding the internal recirculation zone, with residual OH in the recirculation zone approaching chemical equilibrium. Modeling of the OH electronic quenching environment, when compared to fluorescence lifetime measurements, offers additional evidence that the reaction zone burns as a partially premixed flame. A time-series analysis affirms the presence of thin flamelet-like regions based on the relation between swirl-induced turbulence and fluctuations of [OH] in the reaction and recirculation zones. The OH integral time-scales are found to correspond qualitatively to local mean velocities. Furthermore, quantitative dependencies can be established with respect to axial position, Reynolds number, and global equivalence ratio. Given these relationships, the OH time-scales, and thus the primary reaction zone, appear to be dominated by convection-driven fluctuations. Surprisingly, the OH time-scales for these nominally swirling flames demonstrate significant similarities to previous PITLIF results in nonpremixed jet flames. (author)

  7. Hysteresis and transition in swirling nonpremixed flames

    NARCIS (Netherlands)

    Tummers, M.J.; Hübner, A.W.; Veen, van E.H.; Hanjalic, K.; Meer, van der Th.H.

    2009-01-01

    Strongly swirling nonpremixed flames are known to exhibit a hysteresis when transiting from an attached long, sooty, yellow flame to a short lifted blue flame, and vice versa. The upward transition (by increasing the air and fuel flow rates) corresponds to a vortex breakdown, i.e. an abrupt change f

  8. Conditional budgets of second-order statistics in nonpremixed and premixed turbulent combustion

    Science.gov (United States)

    Macart, Jonathan F.; Grenga, Temistocle; Mueller, Michael E.

    2016-11-01

    Combustion heat release modifies or introduces a number of new terms to the balance equations for second-order turbulence statistics (turbulent kinetic energy, scalar variance, etc.) compared to incompressible flow. A major modification is a significant increase in viscosity and dissipation in the high-temperature combustion products, but new terms also appear due to density variation and gas expansion (dilatation). Previous scaling analyses have hypothesized that dilatation effects are important in turbulent premixed combustion but are unimportant in turbulent nonpremixed combustion. To explore this hypothesis, a series of DNS calculations have been performed in the low Mach number limit for spatially evolving turbulent planar jet flames of hydrogen and air in both premixed and nonpremixed configurations. Unlike other studies exploring the effects of heat release on turbulence, the turbulence is not forced, and detailed chemical kinetics are used to describe hydrogen-air combustion. Budgets for second-order statistics are computed conditioned on progress variable in the premixed flame and on mixture fraction in the nonpremixed flame in order to locate regions with respect to the flame structure where dilatation effects are strongest.

  9. Autoignited laminar lifted flames of methane, ethylene, ethane, and n-butane jets in coflow air with elevated temperature

    KAUST Repository

    Choi, Byungchul

    2010-12-01

    The autoignition characteristics of laminar lifted flames of methane, ethylene, ethane, and n-butane fuels have been investigated experimentally in coflow air with elevated temperature over 800. K. The lifted flames were categorized into three regimes depending on the initial temperature and fuel mole fraction: (1) non-autoignited lifted flame, (2) autoignited lifted flame with tribrachial (or triple) edge, and (3) autoignited lifted flame with mild combustion. For the non-autoignited lifted flames at relatively low temperature, the existence of lifted flame depended on the Schmidt number of fuel, such that only the fuels with Sc > 1 exhibited stationary lifted flames. The balance mechanism between the propagation speed of tribrachial flame and local flow velocity stabilized the lifted flames. At relatively high initial temperatures, either autoignited lifted flames having tribrachial edge or autoignited lifted flames with mild combustion existed regardless of the Schmidt number of fuel. The adiabatic ignition delay time played a crucial role for the stabilization of autoignited flames. Especially, heat loss during the ignition process should be accounted for, such that the characteristic convection time, defined by the autoignition height divided by jet velocity was correlated well with the square of the adiabatic ignition delay time for the critical autoignition conditions. The liftoff height was also correlated well with the square of the adiabatic ignition delay time. © 2010 The Combustion Institute.

  10. Opposed Jet Burner Extinction Limits: Simple Mixed Hydrocarbon Scramjet Fuels vs Air

    Science.gov (United States)

    Pellett, Gerald L.; Vaden, Sarah N.; Wilson, Lloyd G.

    2007-01-01

    Opposed Jet Burner tools have been used extensively by the authors to measure Flame Strength (FS) of laminar non-premixed H2 air and simple hydrocarbon (HC) air counterflow diffusion flames at 1-atm. FS represents a strain-induced extinction limit based on air jet velocity. This paper follows AIAA-2006-5223, and provides new HC air FSs for global testing of chemical kinetics, and for characterizing idealized flameholding potentials during early scramjet-like combustion. Previous FS data included six HCs, pure and N2-diluted; and three HC-diluted H2 fuels, where FS decayed very nonlinearly as HC was added to H2, due to H-atom scavenging. This study presents FSs on mixtures of (candidate surrogate) HCs, some with very high FS ethylene. Included are four binary gaseous systems at 300 K, and a hot ternary system at approx. 600 K. The binaries are methane + ethylene, ethane + ethylene, methane + ethane, and methane + propylene. The first three also form two ternary systems. The hot ternary includes both 10.8 and 21.3 mole % vaporized n-heptane and full ranges of methane + ethylene. Normalized FS data provide accurate means of (1) validating, globally, chemical kinetics for extinction of non-premixed flames, and (2) estimating (scaling by HC) the loss of incipient flameholding in scramjet combustors. The n-heptane is part of a proposed baseline simulant (10 mole % with 30% methane + 60% ethylene) that mimics the ignition of endothermically cracked JP-7 like kerosene fuel, as suggested by Colket and Spadaccini in 2001 in their shock tube Scramjet Fuels Autoignition Study. Presently, we use FS to gauge idealized flameholding, and define HC surrogates. First, FS was characterized for hot nheptane + methane + ethylene; then a hot 36 mole % methane + 64% ethylene surrogate was defined that mimics FS of the baseline simulant system. A similar hot ethane + ethylene surrogate can also be defined, but it has lower vapor pressure at 300 K, and thus exhibits reduced gaseous

  11. Implementation variations of adiabatic steady PPDF flamelet model in turbulent H2/air non-premixed combustion simulation

    Directory of Open Access Journals (Sweden)

    Qiong Li

    2015-09-01

    Full Text Available Implementation of the adiabatic steady PPDF flamelet model involves a lot of variations including different scalar dissipation rate calculation methods and different mass diffusion models of the opposed jet flame. Four different look-up tables have been generated with the combinations of two different scalar dissipation rate calculation methods and two different mass diffusion models of the opposed jet flame. Simulation of a turbulent non-premixed H2 jet flame is used to discriminate the accuracy of different implementation methods by comparison with experimental data. It is observed that the turbulent flamelets are very close to their equilibrium states and the simulation result is not sensitive to the choice of dissipation rate calculation method. However, the choice of mass diffusion model has significant influence on the simulation result and excluding the Lewis number effect should be enforced for the opposed jet flame simulation.

  12. Conical quarl swirl stabilized non-premixed flames: flame and flow field interaction

    KAUST Repository

    Elbaz, Ayman M.

    2017-09-19

    The flame-flow field interaction is studied in non-premixed methane swirl flames stabilized in quartz quarl via simultaneous measurements of the flow field using a stereo PIV and OH-PLIF at 5 KHz repetition rate. Under the same swirl intensity, two flames with different fuel jet velocity were investigated. The time-averaged flow field shows a unique flow pattern at the quarl exit, where two recirculation vortices are formed; a strong recirculation zone formed far from the quarl exit and a larger recirculation zone extending inside the quarl. However, the instantaneous images show that, the flow pattern near the quarl exit plays a vital role in the spatial location and structure of the reaction zone. In the low fuel jet velocity flame, a pair of vortical structures, located precisely at the corners of the quarl exit, cause the flame to roll up into the central region of low speed flow, where the flame sheet then tracks the axial velocity fluctuations. The vorticity field reveals a vortical structure surrounding the reaction zones, which reside on a layer of low compressive strain adjacent to that vortical structure. In the high fuel jet velocity flame, initially a laminar flame sheet resides at the inner shear layer of the main jet, along the interface between incoming fresh gas and high temperature recirculating gas. Further downstream, vortex breakdown alters the flame sheet path toward the central flame region. The lower reaction zones show good correlation to the regions of maximum vorticity and track the regions of low compressive strain associated with the inner shear layer of the jet flow. In both flames the reactions zones conform the passage of the large structure while remaining inside the low speed regions or at the inner shear layer.

  13. Adjoint-based sensitivity of flames to ignition parameters in non-premixed shear-flow turbulence

    Science.gov (United States)

    Capecelatro, Jesse; Bodony, Daniel; Freund, Jonathan

    2016-11-01

    The adjoint of the linearized and perturbed compressible flow equations for a mixture of chemically reacting ideal gases is used to assess the sensitivity of ignition in non-premixed shear-flow turbulence. Direct numerical simulations are used to provide an initial prediction, and the corresponding space-time discrete-exact adjoint is used to provide a sensitivity gradient for a specific quantity of interest (QoI). Owing to the ultimately binary outcome of ignition (i.e., it succeeds or fails after some period), a QoI is defined that both quantifies ignition success and varies smoothly near its threshold based on the heat release parameter in a short-time horizon during the ignition process. We use the resulting gradient to quantify the flow properties and model parameters that most affect the initiation of a sustained flame. A line-search algorithm is used to identify regions of high ignition probability and map the boundary between successful and failed ignition. The approach is demonstrated on a non-premixed turbulent shear layer and on a reacting jet-in-crossflow.

  14. NO concentration imaging in turbulent nonpremixed flames

    Energy Technology Data Exchange (ETDEWEB)

    Schefer, R.W. [Sandia National Laboratories, Livermore, CA (United States)

    1993-12-01

    The importance of NO as a pollutant species is well known. An understanding of the formation characteristics of NO in turbulent hydrocarbon flames is important to both the desired reduction of pollutant emissions and the validation of proposed models for turbulent reacting flows. Of particular interest is the relationship between NO formation and the local flame zone, in which the fuel is oxidized and primary heat release occurs. Planar imaging of NO provides the multipoint statistics needed to relate NO formation to the both the flame zone and the local turbulence characteristics. Planar imaging of NO has been demonstrated in turbulent flames where NO was seeded into the flow at high concentrations (2000 ppm) to determine the gas temperature distribution. The NO concentrations in these experiments were significantly higher than those expected in typical hydrocarbon-air flames, which require a much lower detectability limit for NO measurements. An imaging technique based on laser-induced fluorescence with sufficient sensitivity to study the NO formation mechanism in the stabilization region of turbulent lifted-jet methane flames.

  15. Damköhler number effects on soot formation and growth in turbulent nonpremixed flames

    KAUST Repository

    Attili, Antonio

    2015-01-01

    The effect of Damköhler number on turbulent nonpremixed sooting flames is investigated via large scale direct numerical simulation in three-dimensional n-heptane/air jet flames at a jet Reynolds number of 15,000 and at three different Damköhler numbers. A reduced chemical mechanism, which includes the soot precursor naphthalene, and a high-order method of moments are employed. At the highest Damköhler number, local extinction is negligible, while flames holes are observed in the two lowest Damköhler number cases. Compared to temperature and other species controlled by fuel oxidation chemistry, naphthalene is found to be affected more significantly by the Damköhler number. Consequently, the overall soot mass fraction decreases by more than one order of magnitude for a fourfold decrease of the Damköhler number. On the contrary, the overall number density of soot particles is approximately the same, but its distribution in mixture fraction space is different in the three cases. The total soot mass growth rate is found to be proportional to the Damköhler number. In the two lowest Da number cases, soot leakage across the flame is observed. Leveraging Lagrangian statistics, it is concluded that soot leakage is due to patches of soot that cross the stoichiometric surface through flame holes. These results show the leading order effects of turbulent mixing in controlling the dynamics of soot in turbulent flames. © 2014 The Combustion Institute. Published by Elsevier Inc. All rights reserved.

  16. Structure of low-stretch methane nonpremixed flames

    Energy Technology Data Exchange (ETDEWEB)

    Han, Bai; Ibarreta, Alfonso F.; Sung, Chih-Jen; T' ien, James S. [Department of Mechanical and Aerospace Engineering, Case Western Reserve University, Cleveland, OH 44106 (United States)

    2007-04-15

    The present study experimentally and numerically investigates the structure associated with extremely low-stretch ({proportional_to}2 s{sup -1}) gaseous nonpremixed flames. The study of low-stretch flames aims to improve our fundamental understanding of the flame radiation effects on flame response and extinction limits. Low-stretch flames are also relevant to fire safety in reduced-gravity environments and to large buoyant fires, where localized areas of low stretch are attainable. In this work, ultra-low-stretch flames are established in normal gravity by bottom burning of a methane/nitrogen mixture discharged from a porous spherically symmetric burner of large radius of curvature. The large thickness of the resulting nonpremixed flame allows detailed mapping of the flame structure. Several advanced nonintrusive optical diagnostics are used to study the flame structure. Gas phase temperatures are measured by Raman scattering, while the burner surface temperatures are obtained by IR imaging. In addition, OH-PLIF and chemiluminescence imaging techniques are used to help characterize the extent of the flame reaction zone. These experimental results allow direct comparison with a quasi-one-dimensional numerical model including detailed chemistry, thermodynamic/transport properties, and radiation treatment. In addition, the radiative interactions between the flame and porous burner (modeled as a gray surface) are accounted for in the present model. The numerical modeling is demonstrated to be able to simulate the low-stretch flame structure. Using the current model, the extinction limits under different conditions are also examined. The computational results are consistent with experimental observations. (author)

  17. Numerical Investigation of Soot Formation in Non-premixed Flames

    KAUST Repository

    Abdelgadir, Ahmed Gamaleldin

    2017-05-01

    Soot is a carbon particulate formed as a result of the combustion of fossil fuels. Due to the health hazard posed by the carbon particulate, government agencies have applied strict regulations to control soot emissions from road vehicles, airplanes, and industrial plants. Thus, understanding soot formation and evolution is critical. Practical combustion devices operate at high pressure and in the turbulent regime. Elevated pressures and turbulence on soot formation significantly and fundamental understanding of these complex interactions is still poor. In this study, the effects of pressure and turbulence on soot formation and growth are investigated numerically. As the first step, the evolution of the particle size distribution function (PSDF) and soot particles morphology are investigated in turbulent non-premixed flames. A Direct Simulation Monte Carlo (DSMC) code is developed and used. The stochastic reactor describes the evolution of soot in fluid parcels following Lagrangian trajectories in a turbulent flow field. The trajectories are sampled from a Direct Numerical Simulation (DNS) of an n-heptane turbulent non-premixed flame. Although individual trajectories display strong bimodality as in laminar flames, the ensemble-average PSDF possesses only one mode and a broad tail, which implies significant polydispersity induced by turbulence. Secondly, the effect of the flow and mixing fields on soot formation at atmospheric and elevated pressures is investigated in coflow laminar diffusion flames. The experimental observation and the numerical prediction of the spatial distribution are in good agreement. Based on the common scaling methodology of the flames (keeping the Reynolds number constant), the scalar dissipation rate decreases as pressure increases, promoting the formation of PAH species and soot. The decrease of the scalar dissipation rate significantly contributes to soot formation occurring closer to the nozzle and outward on the flames wings as pressure

  18. Nonpremixed flame in a counterflow under electric fields

    KAUST Repository

    Park, Daegeun

    2016-05-08

    Electrically assisted combustion has been studied in order to control or improve flame characteristics, and emphasizing efficiency and emission regulation. Many phenomenological observations have been reported on the positive impact of electric fields on flame, however there is a lack of detailed physical mechanisms for interpreting these. To clarify the effects of electric fields on flame, I have investigated flame structure, soot formation, and flow field with ionic wind electrical current responses in nonpremixed counterflow flames. The effects of direct current (DC) electric field on flame movement and flow field was also demonstrated in premixed Bunsen flames. When a DC electric field was applied to a lower nozzle, the flames moved toward the cathode side due to Lorentz force action on the positive ions, soot particles simultaneously disappeared completely and laser diagnostics was used to identify the results from the soot particles. To understand the effects of an electric field on flames, flow visualization was performed by Mie scattering to check the ionic wind effect, which is considered to play an important role in electric field assisted combustion. Results showed a bidirectional ionic wind, with a double-stagnant flow configuration, which blew from the flame (ionic source) toward both the cathode and the anode. This implies that the electric field affects strain rate and the axial location of stoichiometry, important factors in maintaining nonpremixed counterflow flames; thus, soot formation of the counterflow flame can also be affected by the electric field. In a test of premixed Bunsen flames having parallel electrodes, flame movement toward the cathode and bidirectional ionic wind were observed. Using PIV measurement it was found that a created radial velocity caused by positive ions (i.e. toward a cathode), was much faster than the velocity toward the anode. Even in a study of alternating current (AC) electric fields, bidirectional ionic wind could

  19. A parametric study of AC electric field-induced toroidal vortex formation in laminar nonpremixed coflow flames

    KAUST Repository

    Xiong, Yuan

    2017-05-02

    This study presents an experimental work investigating the controlling parameters on the formation of an electrically-induced inner toroidal vortex (ITV) near a nozzle rim in small, laminar nonpremixed coflow flames, when an alternating current is applied to the nozzle. A systematic parametric study was conducted by varying the flow parameters of the fuel and coflowing-air velocities, and the nozzle diameter. The fuels tested were methane, ethylene, ethane, propane, n-butane, and i-butane, each representing different ion-generation characteristics and sooting tendencies. The results showed that the fluid dynamic effects on ITV formation were weak, causing only mild variation when altering flow velocities. However, increased fuel velocity resulted in increased polycyclic aromatic hydrocarbon (PAH) formation, which promoted ITV formation. When judging the ITV-formation tendency based on critical applied voltage and frequency, it was qualitatively well correlated with the PAH concentration and the relative location of PAHs to the nozzle rim. The sooting tendency of the fuels did not affect the results much. A change in the nozzle diameter highlighted the importance of the relative distance between the PAH zone and the nozzle rim, indicating the role of local electric-field intensity on ITV formation. Detailed onset conditions, characteristics of near-nozzle flow patterns, and PAH distributions are also discussed.

  20. Gaseous Surrogate Hydrocarbons for a Hifire Scramjet that Mimic Opposed Jet Extinction Limits for Cracked JP Fuels

    Science.gov (United States)

    Pellett, Gerald L.; Vaden, Sarah N.; Wilson, Lloyd G.

    2008-01-01

    This paper describes, first, the top-down methodology used to define simple gaseous surrogate hydrocarbon (HC) fuel mixtures for a hypersonic scramjet combustion subtask of the HiFIRE program. It then presents new and updated Opposed Jet Burner (OJB) extinction-limit Flame Strength (FS) data obtained from laminar non-premixed HC vs. air counterflow diffusion flames at 1-atm, which follow from earlier investigations. FS represents a strain-induced extinction limit based on cross-section-average air jet velocity, U(sub air), that sustains combustion of a counter jet of gaseous fuel just before extinction. FS uniquely characterizes a kinetically limited fuel combustion rate. More generally, Applied Stress Rates (ASRs) at extinction (U(sub air) normalized by nozzle or tube diameter, D(sub n or t) can directly be compared with extinction limits determined numerically using either a 1-D or (preferably) a 2-D Navier Stokes simulation with detailed transport and finite rate chemistry. The FS results help to characterize and define three candidate surrogate HC fuel mixtures that exhibit a common FS 70% greater than for vaporized JP-7 fuel. These include a binary fuel mixture of 64% ethylene + 36% methane, which is our primary recommendation. It is intended to mimic the critical flameholding limit of a thermally- or catalytically-cracked JP-7 like fuel in HiFIRE scramjet combustion tests. Our supporting experimental results include: (1) An idealized kinetically-limited ASR reactivity scale, which represents maximum strength non-premixed flames for several gaseous and vaporized liquid HCs; (2) FS characterizations of Colket and Spadaccini s suggested ternary surrogate, of 60% ethylene + 30% methane + 10% n-heptane, which matches the ignition delay of a typical cracked JP fuel; (3) Data showing how our recommended binary surrogate, of 64% ethylene + 36% methane, has an identical FS; (4) Data that characterize an alternate surrogate of 44% ethylene + 56% ethane with identical

  1. Hydrogen-hydrocarbon turbulent non-premixed flame structure

    Energy Technology Data Exchange (ETDEWEB)

    Tabet, F. [ANSYS-Benelux, 4 Avenue Pasteur, B-1300 Wavre (Belgium); Sarh, B.; Goekalp, I. [Institut de Combustion, Aerothermique, Reactivite et Environnement (ICARE), Centre National de la Recherche Scientifique (CNRS), 1 C avenue de la recherche scientifique, Orleans 45071 Cedex 2 (France)

    2009-06-15

    In this study, the structure of turbulent non-premixed CH{sub 4}-H{sub 2}/air flames is analyzed with a special emphasis on mixing and air entrainment. The amount of H{sub 2} in the fuel mixture varies under constant volumetric fuel flow. Mixing is described by mixture fraction and its variance while air entrainment is characterized by the ratio of gas mass flow to fuel mass flow at the inlet section. The flow field and the chemistry are coupled by the flamelet assumption. Mixture fraction and its variance are transported by the computational fluid dynamics (CFD) code. The slow chemistry aspect of NO{sub x} is handled by solving an additional transport equation with a source term derived from flamelet library. The results obtained show an improvement of mixing with hydrogen addition leading to a strong consumption of CH{sub 4} and a high air entrainment into the centerline region. As a global effect of this, the composite fuels burn faster and thereby reduce the residence time which ultimately shortens the flame length and thickness. On the other hand, hydrogen is found to increase NO{sub x} level. (author)

  2. Visualization of ionic wind in laminar jet flames

    KAUST Repository

    Park, Daegeun

    2017-07-03

    Electric field, when it is applied to hydrocarbon flames, generates ionic wind due to the electric body force on charge carrying species. Ionic wind has been shown to influence soot emission, propagation speed, and stability of flames; however, a detailed behavior of ionic wind and its effects on flames is still not clear. Here, we investigated the dynamic behaviors of flames and ionic wind in the presence of direct current (DC) and alternating current (AC) electric fields in nonpremixed and premixed jet flames with a jet nozzle placed between two parallel electrodes. We observed a skewed flame toward a lower potential electrode with DC and lower frequency AC (e.g., 10Hz) and a steady flame with higher frequencies AC (1000Hz), while we found that the ionic wind blew toward both the anode and cathode regardless of flame type (nonpremixed or premixed) or the source of the electric field (DC and AC).

  3. Investigation of soot morphology and particle size distrib ution in a turbulent nonpremixed flame via Monte Carlo simulations

    KAUST Repository

    Abdelgadir, Ahmed

    2015-03-30

    Recently, our group performed a set of direct numerical simulations (DNS) of soot formation and growth in a n-heptane three dimensional non-premixed jet flame [Attili et al., Proc. Comb. Inst, 35, 2015], [Attili et al., Comb. Flame, 161, 2014], [Bisetti et al.,Trans of the Royal Soc, 372, 2014]. The evolution of species relevant to soot formation and growth have been sampled along a large number of Lagrangian trajectories in the DNS. In this work, the DNS results are post-processed to compute the soot evolution along selected Lagrangian trajectories using a Monte Carlo method. An operator splitting approach is adopted to split the deterministic processes (nucleation, surface growth and oxidation) from coagulation, which is treated stochastically. The morphological properties of soot and the particlesize distribution are investigated. For trajectories that experience an early strong nucleation event, the particle size distribution is found to be bimodal, as the soot particles have enough time to coagulate and grow while it is unimodal for trajectories characterized by only late nucleation events. As a results, the average size distribution at two different crosswise positions in the flame is unimodal.

  4. Experimental data regarding the characterization of the flame behavior near lean blowout in a non-premixed liquid fuel burner

    Directory of Open Access Journals (Sweden)

    Maria Grazia De Giorgi

    2016-03-01

    The data are related to the research article “Image processing for the characterization of flame stability in a non-premixed liquid fuel burner near lean blowout” in Aerospace Science and Technology [1].

  5. Tabulated Combustion Model Development For Non-Premixed Flames

    Science.gov (United States)

    Kundu, Prithwish

    Turbulent non-premixed flames play a very important role in the field of engineering ranging from power generation to propulsion. The coupling of fluid mechanics and complicated combustion chemistry of fuels pose a challenge for the numerical modeling of these type of problems. Combustion modeling in Computational Fluid Dynamics (CFD) is one of the most important tools used for predictive modeling of complex systems and to understand the basic fundamentals of combustion. Traditional combustion models solve a transport equation of each species with a source term. In order to resolve the complex chemistry accurately it is important to include a large number of species. However, the computational cost is generally proportional to the cube of number of species. The presence of a large number of species in a flame makes the use of CFD computationally expensive and beyond reach for some applications or inaccurate when solved with simplified chemistry. For highly turbulent flows, it also becomes important to incorporate the effects of turbulence chemistry interaction (TCI). The aim of this work is to develop high fidelity combustion models based on the flamelet concept and to significantly advance the existing capabilities. A thorough investigation of existing models (Finite-rate chemistry and Representative Interactive Flamelet (RIF)) and comparative study of combustion models was done initially on a constant volume combustion chamber with diesel fuel injection. The CFD modeling was validated with experimental results and was also successfully applied to a single cylinder diesel engine. The effect of number of flamelets on the RIF model and flamelet initialization strategies were studied. The RIF model with multiple flamelets is computationally expensive and a model was proposed on the frame work of RIF. The new model was based on tabulated chemistry and incorporated TCI effects. A multidimensional tabulated chemistry database generation code was developed based on the 1

  6. Ethylene glycol blood test

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/article/003564.htm Ethylene glycol blood test To use the sharing features on ... enable JavaScript. This test measures the level of ethylene glycol in the blood. Ethylene glycol is a type ...

  7. Flow instability in laminar jet flames driven by alternating current electric fields

    KAUST Repository

    Kim, Gyeong Taek

    2016-10-13

    The effect of electric fields on the instability of laminar nonpremixed jet flames was investigated experimentally by applying the alternating current (AC) to a jet nozzle. We aimed to elucidate the origin of the occurrence of twin-lifted jet flames in laminar jet flow configurations, which occurred when AC electric fields were applied. The results indicated that a twin-lifted jet flame originated from cold jet instability, caused by interactions between negative ions in the jet flow via electron attachment as O +e→O when AC electric fields were applied. This was confirmed by conducting systematic, parametric experiment, which included changing gaseous component in jets and applying different polarity of direct current (DC) to the nozzle. Using two deflection plates installed in parallel with the jet stream, we found that only negative DC on the nozzle could charge oxygen molecules negatively. Meanwhile, the cold jet instability occurred only for oxygen-containing jets. A shedding frequency of jet stream due to AC driven instability showed a good correlation with applied AC frequency exhibiting a frequency doubling. However, for the applied AC frequencies over 80Hz, the jet did not respond to the AC, indicating an existence of a minimum flow induction time in a dynamic response of negative ions to external AC fields. Detailed regime of the instability in terms of jet velocity, AC voltage and frequency was presented and discussed. Hypothesized mechanism to explain the instability was also proposed.

  8. Bidirectional ionic wind in nonpremixed counterflow flames with DC electric fields

    KAUST Repository

    Park, Daegeun

    2016-05-05

    Under an electric field, ions in the reaction zone of a flame generate a bulk flow motion called ionic wind. Because the majority of ions are positive, ionic wind is commonly considered to be unidirectional toward the cathode. A more thorough understanding of the effects of electric fields on flames could be obtained by clarifying the role of minor negative ions in the ionic wind. Here, we report on the effects of direct current on nonpremixed counterflow flames by visualizing the ionic wind. We found that the original flow field separates near the flame when it locates at a flow stagnation plane, resulting in a double-stagnant flow configuration. This evidences a bidirectional ionic wind blowing from the flame to both the cathode and the anode due to the positive and the negative ions, respectively. Meanwhile, an electric body force pulls the flame toward the cathode. Thus, the electric field affects the strain rate and the axial location of the stoichiometry, which are important for characterizing nonpremixed counterflow flames. In addition, measurement of the electric current density roughly showed a nearly saturated current when these flames restabilized under relatively high voltage. Detailed explanations of flame behavior, electric currents, and flow characteristics of various fuels are discussed in this study.

  9. Turbulent non-premixed combustion driven by the Richtmyer-Meshkov instability

    Science.gov (United States)

    Varshochi, Hilda; Ramaprabhu, Praveen; Attal, Nitesh

    2016-11-01

    We report on 3D high resolution numerical simulations of a non-premixed, reacting Richmyer-Meshkov (RM) instability performed using the FLASH code. In the simulations, a Mach 1.6 shock traverses a diffuse, corrugated material interface separating Hydrogen at 1000 K and Oxygen at 300 K, so that local misalignments between pressure and density gradients induce baroclinic vorticity at the contact line. The vorticity deposition drives the RM instability, which in turn results in combustion and flame formation. We study the evolution of the interface and the flame as the resulting RM instability grows through linear, nonlinear and turbulent stages. We develop a detailed understanding of the effects of heat release and combustion on the underlying flow properties by comparing our results with a baseline non-reacting RM flow. We document the properties of the instability (growth rates, pdfs, spectra) and the flame (scalar dissipation rate, flame surface area, heat release rate) as well as the nature of the coupling between the two. Our findings are relevant to supernovae detonation, knocking in IC engines and scramjet performance, while the underlying flow problem defined here represents a novel canonical framework to understand the broader class of non-premixed turbulent flames.

  10. Error analysis of large-eddy simulation of the turbulent non-premixed sydney bluff-body flame

    NARCIS (Netherlands)

    Kempf, A.M.; Geurts, B.J.; Oefelein, J.C.

    2011-01-01

    A computational error analysis is applied to the large-eddy simulation of the turbulent non-premixed Sydney bluff-body flame, where the error is defined with respect to experimental data. The errorlandscape approach is extended to heterogeneous compressible turbulence, which is coupled to combustion

  11. Effects of AC Electric Field on Small Laminar Nonpremixed Flames

    KAUST Repository

    Xiong, Yuan

    2015-04-01

    baseline case, leading to the formation of toroidal vortices. Increased residence time and heat recirculation inside the vortex resulted in appreciable formation of PAHs and soot near the nozzle exit. Decreased residence time along the jet axis through flow acceleration by the vortex led to a reduction in the soot volume fraction in the downstream sooting zone. Electromagnetic force generated by AC was proposed as a viable mechanism for the formation of the toroidal vortex. By varying applied AC in a wide range of frequency and voltage, several insta- bility modes were observed, including flicking flames, partial pinch-off of flames, and spinning flames. High speed imaging together with Mie scattering techniques were combined to reveal the flame dynamics as well as the flow structure inside the flames. Original steady toroidal vortices triggered by AC were noted to exhibit axisymmetric axial instability in the flicking and partial pinch-off modes and non-axisymmetric azimuthal instability in the spinning mode. Electrical measurements were also conducted simultaneously to identify the voltage, current, and electrical power responses. Integrated power was noted to be sensitive to indicate subtle variation of flames properties and to the occurrence of axial instability. Under low frequency AC forcing with electrical conditions not generating toroidal vortices, responses of flames were further investigated. Several nonlinear flame responses, including frequency doubling and tripling phenomena, were identified. Spectral analysis revealed that such nonlinear responses were attributed to the combined effects of triggering buoyancy-induced oscillation of the flame as well as the Lorenz force generated by applying AC. Phase delay behaviors between the applied voltage and the heat release rate (or flame size) were also studied to explore the potential of applying AC in controlling flame instability. It was found that the phase delay had large variations for AC frequency smaller than

  12. [Direct biosynthesis of ethylene].

    Science.gov (United States)

    Sun, Zhilan; Chen, Yifeng

    2013-10-01

    Ethylene is the most widely used petrochemical feedstock globally. The development of bio-ethylene is essential due to limited fossil fuels and rising oil prices. Bio-ethylene is produced primarily by the dehydration of ethanol, but can alternatively be directly produced from ethylene biosynthesis pathways in plants, algae, or microorganisms by using cheap and renewable substrates. This review addressed the biosynthesis of ethylene in plants and microorganisms, the characterization of key enzymes, genetic engineering strategies for ethylene biosynthesis in microorganisms, and evaluated its perspective and successful cases toward the industrial application. The direct production of bio-ethylene from a biological process in situ is promising to supplement and even replace the petrochemical ethylene production.

  13. Experimental study on velocity characteristics of recirculation zone in humid air non-premixed flame

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    To examine the effect of the flow field within the recirculation zone on flame structure,the characteristic velocity fields of methane/humid air flame in nonpremixed combustion behind a disc bluff-body burner were experimentally studied by particle image velocimeter (PIV).The results show that two stagnation points exist on the centerline in the recirculation zone flame.However,the distance of the two stagnation points in humid air combustion shortens,and the minimal dimensionless velocity increases compared with the conventional nonhumid air combustion.In addition,the positional curves of the minimal velocities can be partitioned into three phases representing three different flame patterns.The analysis of axial minimal velocities on the centerline and their positions under different co-flow air velocity conditions reveals that fuel-to-air velocity ratio is the crucial parameter that governs humid air combustion flame characteristics.

  14. Explosive Combustion of a Neutron Star into a Quark Star: the non-premixed scenario

    CERN Document Server

    Ouyed, Rachid; Jaikumar, Prashanth

    2013-01-01

    We review aspects of the hydrodynamical combustion of nuclear matter to strange quark matter in a neutron star. Numerical studies on non-premixed combustion that consistently include hydrodynamical flows in a reactive-diffusive setup show that in 1D, the conversion (burning) front moves at sub-sonic speeds and stops short of converting the entire star to SQM, essentially due to advective forces. However, in the process, we also find that neutrino cooling of the interface causes it to wrinkle, laying a platform for a deflagrative-to-detonative transition (DDT). We outline progress on improvements in the burning code (Burn-UD: http://quarknova.ucalgary.ca/software/Burn-UD/) that will ultimately reveal the mechanism that can explode the outermost layers of even a dense compact object like a neutron star.

  15. Study and modeling of finite rate chemistry effects in turbulent non-premixed flames

    Science.gov (United States)

    Vervisch, Luc

    1993-01-01

    The development of numerical models that reflect some of the most important features of turbulent reacting flows requires information about the behavior of key quantities in well defined combustion regimes. In turbulent flames, the coupling between turbulent and chemical processes is so strong that it is extremely difficult to isolate the role played by one individual physical phenomenon. Direct numerical simulation (hereafter DNS) allows us to study in detail the turbulence-chemistry interaction in some restricted but completely defined situations. Globally, non-premixed flames are controlled by two limiting regimes: the fast chemistry case, where the turbulent flame can be pictured as a random distribution of local chemical equilibrium problems; and the slow chemistry case, where the chemistry integrates in time the turbulent fluctuations. The Damkoehler number, ratio of a mechanical time scale to chemical time scale, is used to distinguish between these regimes. Today most of the industrial computer codes are able to perform predictions in the hypothesis of local equilibrium chemistry using a presumed shape for the probability density function (pdt) of the conserved scalar. However, the finite rate chemistry situation is of great interest because industrial burners usually generate regimes in which, at some points, the flame is undergoing local extinction or at least non-equilibrium situations. Moreover, this variety of situations strongly influences the production of pollutants. To quantify finite rate chemistry effect, the interaction between a non-premixed flame and a free decaying turbulence is studied using DNS. The attention is focused on the dynamic of extinction, and an attempt is made to quantify the effect of the reaction on the small scale mixing process. The unequal diffusivity effect is also addressed. Finally, a simple turbulent combustion model based on the DNS observations and tractable in real flow configurations is proposed.

  16. Twin Jet

    Science.gov (United States)

    Henderson, Brenda; Bozak, Rick

    2010-01-01

    Many subsonic and supersonic vehicles in the current fleet have multiple engines mounted near one another. Some future vehicle concepts may use innovative propulsion systems such as distributed propulsion which will result in multiple jets mounted in close proximity. Engine configurations with multiple jets have the ability to exploit jet-by-jet shielding which may significantly reduce noise. Jet-by-jet shielding is the ability of one jet to shield noise that is emitted by another jet. The sensitivity of jet-by-jet shielding to jet spacing and simulated flight stream Mach number are not well understood. The current experiment investigates the impact of jet spacing, jet operating condition, and flight stream Mach number on the noise radiated from subsonic and supersonic twin jets.

  17. CFD Studies of Combustion in Direct Injection Single Cylinder Diesel Engine Using Non-Premixed Combustion Model

    Directory of Open Access Journals (Sweden)

    S Gavudhama Karunanidhi

    2014-07-01

    Full Text Available In this study the simulation process of non-premixed combustion in a direct injection single cylinder diesel engine has been described. Direct injection diesel engines are used both in heavy duty vehicles and light duty vehicles. The fuel is injected directly into the combustion chamber. The fuel mixes with the high pressure air in the combustion chamber and combustion occurs. Due to the non-premixed nature of the combustion occurring in such engines, non-premixed combustion model of ANSYS FLUENT 14.5 can be used to simulate the combustion process. A 4-stroke diesel engine corresponds to one fuel injector hole without considering valves was modeled and combustion simulation process was studied. Here two types of combustion chambers were compared. Combustion studies of both chambers:- shallow depth and hemispherical combustion chambers were carried out. Emission characteristics of both combustion chambers had also been carried out. The obtained results are compared. It has been found that hemispherical combustion chamber is more efficient as it produces higher pressure and temperature compared to that of shallow depth combustion chamber. As the temperature increases the formation of NOx emissions and soot formation also get increased.

  18. Jet observables without jet algorithms

    Energy Technology Data Exchange (ETDEWEB)

    Bertolini, Daniele; Chan, Tucker; Thaler, Jesse [Center for Theoretical Physics, Massachusetts Institute of Technology,Cambridge, MA 02139 (United States)

    2014-04-02

    We introduce a new class of event shapes to characterize the jet-like structure of an event. Like traditional event shapes, our observables are infrared/collinear safe and involve a sum over all hadrons in an event, but like a jet clustering algorithm, they incorporate a jet radius parameter and a transverse momentum cut. Three of the ubiquitous jet-based observables — jet multiplicity, summed scalar transverse momentum, and missing transverse momentum — have event shape counterparts that are closely correlated with their jet-based cousins. Due to their “local” computational structure, these jet-like event shapes could potentially be used for trigger-level event selection at the LHC. Intriguingly, the jet multiplicity event shape typically takes on non-integer values, highlighting the inherent ambiguity in defining jets. By inverting jet multiplicity, we show how to characterize the transverse momentum of the n-th hardest jet without actually finding the constituents of that jet. Since many physics applications do require knowledge about the jet constituents, we also build a hybrid event shape that incorporates (local) jet clustering information. As a straightforward application of our general technique, we derive an event-shape version of jet trimming, allowing event-wide jet grooming without explicit jet identification. Finally, we briefly mention possible applications of our method for jet substructure studies.

  19. Ethylene insensitive plants

    Science.gov (United States)

    Ecker, Joseph R.; Nehring, Ramlah; McGrath, Robert B.

    2007-05-22

    Nucleic acid and polypeptide sequences are described which relate to an EIN6 gene, a gene involved in the plant ethylene response. Plant transformation vectors and transgenic plants are described which display an altered ethylene-dependent phenotype due to altered expression of EIN6 in transformed plants.

  20. Experimental and Kinetic Modeling Study of Extinction and Ignition of Methyl Decanoate in Laminar Nonpremixed Flows

    Energy Technology Data Exchange (ETDEWEB)

    Seshadri, K; Lu, T; Herbinet, O; Humer, S; Niemann, U; Pitz, W J; Law, C K

    2008-01-09

    Methyl decanoate is a large methyl ester that can be used as a surrogate for biodiesel. In this experimental and computational study, the combustion of methyl decanoate is investigated in nonpremixed, nonuniform flows. Experiments are performed employing the counterflow configuration with a fuel stream made up of vaporized methyl decanoate and nitrogen, and an oxidizer stream of air. The mass fraction of fuel in the fuel stream is measured as a function of the strain rate at extinction, and critical conditions of ignition are measured in terms of the temperature of the oxidizer stream as a function of the strain rate. It is not possible to use a fully detailed mechanism for methyl decanoate to simulate the counterflow flames because the number of species and reactions is too large to employ with current flame codes and computer resources. Therefore a skeletal mechanism was deduced from a detailed mechanism of 8555 elementary reactions and 3036 species using 'directed relation graph' method. This skeletal mechanism has only 713 elementary reactions and 125 species. Critical conditions of ignition were calculated using this skeletal mechanism and are found to agree well with experimental data. The predicted strain rate at extinction is found to be lower than the measurements. In general, the methyl decanoate mechanism provides a realistic kinetic tool for simulation of biodiesel fuels.

  1. Proceedings of the international workshop on measurement and computation of turbulent nonpremixed flames

    Energy Technology Data Exchange (ETDEWEB)

    Barlow, R.S. [ed.

    1996-10-01

    This report documents the proceedings of the International Workshop on Measurement and Computation of Turbulent Nonpremixed Flames, held in Naples, Italy on July 26--27, 1996. Contents include materials that were distributed to participants at the beginning of the workshop, as well as a Summary of Workshop Accomplishments that was generated at the close to this Naples meeting. The Naples workshop involved sixty-one people from eleven countries. The primary objectives were: (1) to select a set of well-documented and relatively simple flames that would be appropriate for collaborative comparisons of model predictions; and (2) to specify common submodels to be used in these predictions, such that models for the coupling of turbulence and chemistry might be isolated and better understood. Studies involve hydrogen and natural gas fuels. These proceedings are also published on the Web and those interested in the ongoing process of data selection and model comparison should consult the workshop page for the most recent and complete information on these collaborative research efforts. The URL is: http://www/ca.sandia/gov/tdf/Workshop.html.

  2. Propagating nonpremixed edge-flames in a counterflow, annular slot burner under DC electric fields

    KAUST Repository

    Tran, Vu Manh

    2016-09-11

    Characteristics of propagating nonpremixed edge-flames were investigated in a counterflow, annular slot burner. A high-voltage direct current (DC) was applied to the lower part of the burner and the upper part was grounded, creating electric field lines perpendicular to the direction of edge-flame propagation. Upon application of an electric field, an ionic wind is caused by the migration of positive and negative ions to lower and higher electrical potential sides of a flame, respectively. Under an applied DC, we found a significant decrease in edge-flame displacement speeds unlike several previous studies, which showed an increase in displacement speed. Within a moderate range of field intensity, we found effects on flame propagation speeds to be negligible after correcting the flame displacement speed with respect to the unburned flow velocity ahead of the flame edge. This indicates that the displacement speed of an edge-flame strongly depends on ionic wind and that an electric field has little or no impact on propagation speed. The ionic wind also influenced the location of the stoichiometric contour in front of the propagating edge in a given configuration such that a propagating edge was relocated to the higher potential side due to an imbalance between ionic winds originating from positive and negative ions. In addition, we observed a steadily wrinkled flame following transient propagation of the edge-flame, a topic for future research. © 2016 The Combustion Institute

  3. A numerical study on extinction and NOx formation in nonpremixed flames with syngas fuel

    KAUST Repository

    Chun, Kangwoo

    2011-11-01

    The flame structure, extinction, and NOx emission characteristics of syngas/air nonpremixed flames, have been investigated numerically. The extinction stretch rate increased with the increase in the hydrogen proportion in the syngas and with lower fuel dilution and higher initial temperature. It also increased with pressure, except for the case of highly diluted fuel at high pressure. The maximum temperature and the emission index of nitric oxides (EINOx) also increased in aforementioned conditions. The EINOx decreased with stretch rate in general, while the decreasing rate was found to be somewhat different between the cases of N2 and CO2 dilutions. The reaction paths of NOx formation were analyzed and represented as NO reaction path diagram. The increase in N radical resulted in larger NOx production at high initial temperature and pressure. As the pressure increases, EINOx increases slower due to the third-body recombination. The thermal NO mechanism is weakened for high dilution cases and non-thermal mechanisms prevail. The combustion conditions achieving higher extinction stretch rate can be lead to more NOx emission, therefore that the selection of optimum operation range is needed in syngas combustion. © 2011 The Korean Society of Mechanical Engineers and Springer-Verlag Berlin Heidelberg.

  4. Direct numerical simulations of turbulent non-premixed methane-air flames modeled with reduced kinetics

    Science.gov (United States)

    Card, J. M.; Chen, J. H.; Day, M.; Mahalingam, S.

    1994-01-01

    Turbulent non-premixed stoichiometric methane-air flames modeled with reduced kinetics have been studied using the direct numerical simulation approach. The simulations include realistic chemical kinetics, and the molecular transport is modeled with constant Lewis numbers for individual species. The effect of turbulence on the internal flame structure and extinction characteristics of methane-air flames is evaluated. Consistent with earlier DNS with simple one-step chemistry, the flame is wrinkled and in some regions extinguished by the turbulence, while the turbulence is weakened in the vicinity of the flame due to a combination of dilatation and an increase in kinematic viscosity. Unlike previous results, reignition is observed in the present simulations. Lewis number effects are important in determining the local stoichiometry of the flame. The results presented in this work are preliminary but demonstrate the feasibility of incorporating reduced kinetics for the oxidation of methane with direct numerical simulations of homogeneous turbulence to evaluate the limitations of various levels of reduction in the kinetics and to address the formation of thermal and prompt NO(x).

  5. Investigation on Effect of Air Velocity in Turbulent Non-Premixed Flames

    Directory of Open Access Journals (Sweden)

    Namazian Zafar

    2016-09-01

    Full Text Available In this study, the turbulent non-premixed methane-air flame is simulated to determine the effect of air velocity on the length of flame, temperature distribution and mole fraction of species. The computational fluid dynamics (CFD technique is used to perform this simulation. To solve the turbulence flow, k-ε model is used. In contrast to the previous works, in this study, in each one of simulations the properties of materials are taken variable and then the results are compared. The results show that at a certain flow rate of fuel, by increasing the air velocity, similar to when the properties are constant, the width of the flame becomes thinner and the maximum temperature is higher; the penetration of oxygen into the fuel as well as fuel consumption is also increased. It is noteworthy that most of the pollutants produced are NOx, which are strongly temperature dependent. The amount of these pollutants rises when the temperature is increased. As a solution, decreasing the air velocity can decrease the amount of these pollutants. Finally, comparing the result of this study and the other work, which considers constant properties, shows that the variable properties assumption leads to obtaining more exact solution but the trends of both results are similar.

  6. Ethylene, seed germination, and epinasty.

    Science.gov (United States)

    Stewart, E R; Freebairn, H T

    1969-07-01

    Ethylene activity in lettuce seed (Lactuca satina) germination and tomato (Lycopersicon esculentum) petiole epinasty has been characterized by using heat to inhibit ethylene synthesis. This procedure enabled a separation of the production of ethylene from the effect of ethylene. Ethylene was required in tomato petioles to produce the epinastic response and auxin was found to be active in producing epinasty through a stimulation of ethylene synthesis with the resulting ethylene being responsible for the epinasty. In the same manner, it was shown that gibberellic acid stimulated ethylene synthesis in lettuce seeds. The ethylene produced then in turn stimulated the seeds to germinate. It was hypothesized that ethylene was the intermediate which caused epinasty or seed germination. Auxin and gibberellin primarily induced their response by stimulating ethylene production.

  7. A numerical study of mixing in stationary, nonpremixed, turbulent reacting flows

    Science.gov (United States)

    Overholt, Matthew Ryan

    1998-10-01

    In this work a detailed numerical study is made of a statistically-stationary, non-premixed, turbulent reacting model flow known as Periodic Reaction Zones. The mixture fraction-progress variable approach is used, with a mean gradient in the mixture fraction and a model, single-step, reversible, finite-rate thermochemistry, yielding both stationary and local extinction behavior. The passive scalar is studied first, using a statistical forcing scheme to achieve stationarity of the velocity field. Multiple independent direct numerical simulations (DNS) are performed for a wide range of Reynolds numbers with a number of results including a bilinear model for scalar mixing jointly conditioned on the scalar and x2-component of velocity, Gaussian scalar probability density function tails which were anticipated to be exponential, and the quantification of the dissipation of scalar flux. A new deterministic forcing scheme for DNS is then developed which yields reduced fluctuations in many quantities and a more natural evolution of the velocity fields. This forcing method is used for the final portion of this work. DNS results for Periodic Reaction Zones are compared with the Conditional Moment Closure (CMC) model, the Quasi-Equilibrium Distributed Reaction (QEDR) model, and full probability density function (PDF) simulations using the Euclidean Minimum Spanning Tree (EMST) and the Interaction by Exchange with the Mean (IEM) mixing models. It is shown that CMC and QEDR results based on the local scalar dissipation match DNS wherever local extinction is not present. However, due to the large spatial variations of scalar dissipation, and hence local Damkohler number, local extinction is present even when the global Damkohler number is twenty-five times the critical value for extinction. Finally, in the PDF simulations the EMST mixing model closely reproduces CMC and DNS results when local extinction is not present, whereas the IEM model results in large error.

  8. Dynamics of flow–soot interaction in wrinkled non-premixed ethylene–air flames

    KAUST Repository

    Arias, Paul G.

    2015-08-17

    A two-dimensional simulation of a non-premixed ethylene–air flame was conducted by employing a detailed gas-phase reaction mechanism considering polycyclic aromatic hydrocarbons, an aerosol-dynamics-based soot model using a method of moments with interpolative closure, and a grey gas and soot radiation model using the discrete transfer method. Interaction of the sooting flame with a prescribed decaying random velocity field was investigated, with a primary interest in the effects of velocity fluctuations on the flame structure and the associated soot formation process for a fuel-strip configuration and a composition with mature soot growth. The temporally evolving simulation revealed a multi-layered soot formation process within the flame, at a level of detail not properly described by previous studies based on simplified soot models utilizing acetylene or naphthalene precursors for initial soot inception. The overall effect of the flame topology on the soot formation was found to be consistent with previous experimental studies, while a unique behaviour of localised strong oxidation was also noted. The imposed velocity fluctuations led to an increase of the scalar dissipation rate in the sooting zone, causing a net suppression in the soot production rate. Considering the complex structure of the soot formation layer, the effects of the imposed fluctuations vary depending on the individual soot reactions. For the conditions under study, the soot oxidation reaction was identified as the most sensitive to the fluctuations and was mainly responsible for the local suppression of the net soot production. © 2015 Taylor & Francis

  9. Simulation and analysis of the soot particle size distribution in a turbulent nonpremixed flame

    KAUST Repository

    Lucchesi, Marco

    2017-02-05

    A modeling framework based on Direct Simulation Monte Carlo (DSMC) is employed to simulate the evolution of the soot particle size distribution in turbulent sooting flames. The stochastic reactor describes the evolution of soot in fluid parcels following Lagrangian trajectories in a turbulent flow field. The trajectories are sampled from a Direct Numerical Simulation (DNS) of a n-heptane turbulent nonpremixed flame. The DSMC method is validated against experimentally measured size distributions in laminar premixed flames and found to reproduce quantitatively the experimental results, including the appearance of the second mode at large aggregate sizes and the presence of a trough at mobility diameters in the range 3–8 nm. The model is then applied to the simulation of soot formation and growth in simplified configurations featuring a constant concentration of soot precursors and the evolution of the size distribution in time is found to depend on the intensity of the nucleation rate. Higher nucleation rates lead to a higher peak in number density and to the size distribution attaining its second mode sooner. The ensemble-averaged PSDF in the turbulent flame is computed from individual samples of the PSDF from large sets of Lagrangian trajectories. This statistical measure is equivalent to time-averaged, scanning mobility particle size (SMPS) measurements in turbulent flames. Although individual trajectories display strong bimodality as in laminar flames, the ensemble-average PSDF possesses only one mode and a long, broad tail, which implies significant polydispersity induced by turbulence. Our results agree very well with SMPS measurements available in the literature. Conditioning on key features of the trajectory, such as mixture fraction or radial locations does not reduce the scatter in the size distributions and the ensemble-averaged PSDF remains broad. The results highlight and explain the important role of turbulence in broadening the size distribution of

  10. Fuzzy jets

    Energy Technology Data Exchange (ETDEWEB)

    Mackey, Lester [Department of Statistics, Stanford University,Stanford, CA 94305 (United States); Nachman, Benjamin [Department of Physics, Stanford University,Stanford, CA 94305 (United States); SLAC National Accelerator Laboratory, Stanford University,2575 Sand Hill Rd, Menlo Park, CA 94025 (United States); Schwartzman, Ariel [SLAC National Accelerator Laboratory, Stanford University,2575 Sand Hill Rd, Menlo Park, CA 94025 (United States); Stansbury, Conrad [Department of Physics, Stanford University,Stanford, CA 94305 (United States)

    2016-06-01

    Collimated streams of particles produced in high energy physics experiments are organized using clustering algorithms to form jets. To construct jets, the experimental collaborations based at the Large Hadron Collider (LHC) primarily use agglomerative hierarchical clustering schemes known as sequential recombination. We propose a new class of algorithms for clustering jets that use infrared and collinear safe mixture models. These new algorithms, known as fuzzy jets, are clustered using maximum likelihood techniques and can dynamically determine various properties of jets like their size. We show that the fuzzy jet size adds additional information to conventional jet tagging variables in boosted topologies. Furthermore, we study the impact of pileup and show that with some slight modifications to the algorithm, fuzzy jets can be stable up to high pileup interaction multiplicities.

  11. CSP-based chemical kinetics mechanisms simplification strategy for non-premixed combustion: An application to hybrid rocket propulsion

    KAUST Repository

    Ciottoli, Pietro P.

    2017-08-14

    A set of simplified chemical kinetics mechanisms for hybrid rocket applications using gaseous oxygen (GOX) and hydroxyl-terminated polybutadiene (HTPB) is proposed. The starting point is a 561-species, 2538-reactions, detailed chemical kinetics mechanism for hydrocarbon combustion. This mechanism is used for predictions of the oxidation of butadiene, the primary HTPB pyrolysis product. A Computational Singular Perturbation (CSP) based simplification strategy for non-premixed combustion is proposed. The simplification algorithm is fed with the steady-solutions of classical flamelet equations, these being representative of the non-premixed nature of the combustion processes characterizing a hybrid rocket combustion chamber. The adopted flamelet steady-state solutions are obtained employing pure butadiene and gaseous oxygen as fuel and oxidizer boundary conditions, respectively, for a range of imposed values of strain rate and background pressure. Three simplified chemical mechanisms, each comprising less than 20 species, are obtained for three different pressure values, 3, 17, and 36 bar, selected in accordance with an experimental test campaign of lab-scale hybrid rocket static firings. Finally, a comprehensive strategy is shown to provide simplified mechanisms capable of reproducing the main flame features in the whole pressure range considered.

  12. Modelling of Turbulent Nonpremixed CH4/H2 Flame Using Second-Moment Turbulence Closure Models

    Institute of Scientific and Technical Information of China (English)

    李国岫

    2005-01-01

    Turbulent nonpremixed CH4/H2 flame has been simulated using several typical differential secondmoment turbulence closure (SMTC) models. To clarify the applicability of the various models, the LRR-IP model,JM model, SSG model as well as two modified LRR-IP models were tested. Some of above-mentioned SMTC models cannot provide the overall satisfactory predictions of this challenging case. It is confirmed again that the standard LRR-IP model considerably overpredict the centerline velocity decay rate, and therefore performs not well. Also it is interesting to observe that the JM model does not perform well in this challenging test case, although it has already been proved successful in other cases. The SSG model produces quite satisfactory prediction and performs equally well or better than the two modified LRR-IP models in the reacting case. It can be concluded that the modified LRR-IP models as well as the SSG model are superior to the other SMTC models in the turbulent nonpremixed CH4/H2 flame.

  13. Rotational spectrum of the tetrafluoromethane-ethylene oxide

    Science.gov (United States)

    Gou, Qian; Feng, Gang; Evangelisti, Luca; Caminati, Walther

    2017-05-01

    The rotational spectrum of one conformer of the CF4-ethylene oxide complex has been measured by using a pulsed jet Fourier-transform microwave spectrometer. The observed conformer is stabilized by a CF3⋯O halogen bond, with a distance rC⋯O of ∼3.341 Å. No experimental evidence of the internal rotation of CF4 with respect to ethylene oxide has been observed, but it is expected to be almost free (V3 ∼ 14 cm-1 from ab initio calculations).

  14. Jet Observables Without Jet Algorithms

    CERN Document Server

    Bertolini, Daniele; Thaler, Jesse

    2013-01-01

    We introduce a new class of event shapes to characterize the jet-like structure of an event. Like traditional event shapes, our observables are infrared/collinear safe and involve a sum over all hadrons in an event, but like a jet clustering algorithm, they incorporate a jet radius parameter and a transverse momentum cut. Three of the ubiquitous jet-based observables---jet multiplicity, summed scalar transverse momentum, and missing transverse momentum---have event shape counterparts that are closely correlated with their jet-based cousins. Due to their "local" computational structure, these jet-like event shapes could potentially be used for trigger-level event selection at the LHC. Intriguingly, the jet multiplicity event shape typically takes on non-integer values, highlighting the inherent ambiguity in defining jets. By inverting jet multiplicity, we show how to characterize the transverse momentum of the n-th hardest jet without actually finding the constituents of that jet. Since many physics applicatio...

  15. Investigation of the effects of quarl and initial conditions on swirling non-premixed methane flames: Flow field, temperature, and species distributions

    KAUST Repository

    Elbaz, Ayman M.

    2015-12-19

    Detailed measurements are presented of the turbulent flow field, gas species concentrations and temperature field in a non-premixed methane swirl flame. Attention is given to the effect of the quarl geometry on the flame structure and emission characteristics due to its importance in gas turbine and industrial burner applications. Two different quarls were fitted to the burner exit, one a straight quarl and the other a diverging quarl of 15° half cone angle. Stereoscopic Particle Image Velocimetry (SPIV) was applied to obtain the three components of the instantaneous velocity on a vertical plane immediately downstream of the quarl exit. Temperature and gaseous species measurements were made both inside and downstream of the quarls, using a fine wire thermocouple and sampling probe, respectively. This work provides experimental verification by complementary techniques. The results showed that although the main flame structures were governed by the swirl motion imparted to the air stream, the quarl geometry, fuel loading and air loading also had a significant effect on the flow pattern, turbulence intensity, mixture formation, temperature distribution, emissions and flame stabilization. Particularly, in the case of the straight quarl flame, the flow pattern leads to strong, rapid mixing and reduces the residence time for NO formation within the internal recirculation zone (IRZ). However, for the diverging quarl flames, the recirculation zone is shifted radially outward, and the turbulent interaction between the central fuel jet and the internal recirculation zone IRZ induces another small vortex between these two flow features. Less mixing near the diverging quarl exit is observed, with a higher concentration of NO and CO in the post-combustion zone. The instantaneous flow field for both flames showed the existence of small scale vortical structure near the shear layers which were not apparent in the time averaged flow field. These structures, along with high levels

  16. On the formation and early evolution of soot in turbulent nonpremixed flames

    KAUST Repository

    Bisetti, Fabrizio

    2012-01-01

    A Direct Numerical Simulation (DNS) of soot formation in an n-heptane/air turbulent nonpremixed flame has been performed to investigate unsteady strain effects on soot growth and transport. For the first time in a DNS of turbulent combustion, Polycyclic Aromatic Hydrocarbons (PAH) are included via a validated, reduced chemical mechanism. A novel statistical representation of soot aggregates based on the Hybrid Method of Moments is used [M.E. Mueller, G. Blanquart, H. Pitsch, Combust. Flame 156 (2009) 1143-1155], which allows for an accurate state-of-the-art description of soot number density, volume fraction, and morphology of the aggregates. In agreement with previous experimental studies in laminar flames, Damköhler number effects are found to be significant for PAH. Soot nucleation and growth from PAH are locally inhibited by high scalar dissipation rate, thus providing a possible explanation for the experimentally observed reduction of soot yields at increasing levels of mixing in turbulent sooting flames. Furthermore, our data indicate that soot growth models that rely on smaller hydrocarbon species such as acetylene as a proxy for large PAH molecules ignore or misrepresent the effects of turbulent mixing and hydrodynamic strain on soot formation due to differences in the species Damköhler number. Upon formation on the rich side of the flame, soot is displaced relative to curved mixture fraction iso-surfaces due to differential diffusion effects between soot and the gas-phase. Soot traveling towards the flame is oxidized, and aggregates displaced away from the flame grow primarily by condensation of PAH on the particle surface. In contrast to previous DNS studies based on simplified soot and chemistry models, surface reactions are found to contribute barely to the growth of soot, for nucleation and condensation processes occurring in the fuel stream are responsible for the most of soot mass generation. Furthermore, the morphology of the soot aggregates is

  17. DEVELOPMENT TREND OF ETHYLENE INDUSTRY

    Institute of Scientific and Technical Information of China (English)

    Song Ting

    2014-01-01

    The growth of world ethylene production and demand has been slowed down, but accelarated growth after 2015 is forecasted. Shale gas revolution has promoted the resurge of ethylene industry in North America and changed the investment pattern of world ethylene industry.Chinese ethylene industry has developed rapidly, facing not only opportunities for development but also outside pressure.The diversified pattern of Chinese ethylene industry has been formed , in which MTO has become an effective complement to the ethylene industry.While cracking raw material has become lighter and lighter worldwide, naphtha still dominates the ethylene raw material in China, leading to high cost of raw material.Aiming to reduce the cost and improve the competitiveness, this article introduces the progress of steam cracking technology for ethylene production from the aspects of low energy consumption , low cost, large capacity and long-term operation.

  18. AUXIN STIMULATION OF ETHYLENE EVOLUTION

    Science.gov (United States)

    mechanism of auxin action on the enhancement of ethylene production is the formation of enzymes involved in ethylene biogenesis....The stimulation of ethylene production by auxin was inhibited by actinomycin D and other inhibitors of protein synthesis. It is concluded that the

  19. Ethylene production by apple protoplasts.

    Science.gov (United States)

    Anderson, J D; Lieberman, M; Stewart, R N

    1979-05-01

    Freshly prepared protoplasts from apple tissue that produced ethylene were obtained. Ethylene production was inhibited by osmotic shock, 0.01% Triton X-100, and aminoethoxyvinyl glycine. Protoplasts as well as the ethylene system were not greatly affected by protease treatment.

  20. Jet quenching via jet collimation

    CERN Document Server

    Casalderrey-Solana, J; Wiedemann, U

    2011-01-01

    The strong modifications of dijet properties in heavy ion collisions measured by ATLAS and CMS provide important constraints on the dynamical mechanisms underlying jet quenching. In this work, we show that the transport of soft gluons away from the jet cone - jet collimation - can account for the observed dijet asymmetry with values of $\\hat{q}\\, L$ that lie in the expected order of magnitude. Further, we show that the energy loss attained through this mechanism results in a very mild distortion of the azimuthal angle dijet distribution.

  1. Emerging jets

    Energy Technology Data Exchange (ETDEWEB)

    Schwaller, Pedro; Stolarski, Daniel [European Organization for Nuclear Research (CERN), Geneva (Switzerland). TH-PH Div.; Weiler, Andreas [European Organization for Nuclear Research (CERN), Geneva (Switzerland). TH-PH Div.; Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany)

    2015-02-15

    In this work, we propose a novel search strategy for new physics at the LHC that utilizes calorimeter jets that (i) are composed dominantly of displaced tracks and (ii) have many different vertices within the jet cone. Such emerging jet signatures are smoking guns for models with a composite dark sector where a parton shower in the dark sector is followed by displaced decays of dark pions back to SM jets. No current LHC searches are sensitive to this type of phenomenology. We perform a detailed simulation for a benchmark signal with two regular and two emerging jets, and present and implement strategies to suppress QCD backgrounds by up to six orders of magnitude. At the 14 TeV LHC, this signature can be probed with mediator masses as large as 1.5 TeV for a range of dark pion lifetimes, and the reach is increased further at the high-luminosity LHC. The emerging jet search is also sensitive to a broad class of long-lived phenomena, and we show this for a supersymmetric model with R-parity violation. Possibilities for discovery at LHCb are also discussed.

  2. Emerging Jets

    CERN Document Server

    Schwaller, Pedro; Weiler, Andreas

    2015-01-01

    In this work, we propose a novel search strategy for new physics at the LHC that utilizes calorimeter jets that (i) are composed dominantly of displaced tracks and (ii) have many different vertices within the jet cone. Such emerging jet signatures are smoking guns for models with a composite dark sector where a parton shower in the dark sector is followed by displaced decays of dark pions back to SM jets. No current LHC searches are sensitive to this type of phenomenology. We perform a detailed simulation for a benchmark signal with two regular and two emerging jets, and present and implement strategies to suppress QCD backgrounds by up to six orders of magnitude. At the 14 TeV LHC, this signature can be probed with mediator masses as large as 1.5 TeV for a range of dark pion lifetimes, and the reach is increased further at the high-luminosity LHC. The emerging jet search is also sensitive to a broad class of long-lived phenomena, and we show this for a supersymmetric model with R-parity violation. Possibilit...

  3. An experimental study on turbulent lifted flames of methane in coflow jets at elevated temperatures

    KAUST Repository

    Choi, Byungchul

    2013-01-01

    An experimental study was conducted on the effects of initial temperature variation on the stabilization characteristics of turbulent nonpremixed flames in coflow jets of methane fuel diluted by nitrogen. The typical behavior seen in the study showed that the liftoff height increased linearly with the jet velocity regardless of the initial temperature in the turbulent regime. Two models were investigated for predicting liftoff heights in the methane jets: the premixed flame model and the large-scale mixing model. For the premixed flame model, the liftoff heights in the methane jets were accurately predicted using the thermal diffusivity of the unburned gas temperature αst,0, instead of that of the burned gas temperature αst,b. For the large-scale mixing model, however, the prediction of liftoff heights differed slightly for the various fuel mole fractions. However, when considering the initial fuel mass fraction YF,0, the liftoff heights were successfully predicted. This result implies that the characteristics of the unburned fuel-air mixture play a crucial role for flame stabilization in coflow jets for a variety of initial conditions. In the turbulent regime, the blowout velocity and the liftoff height at blowout could be accurately predicted by the two models based on a consideration of the physical properties and the buoyancy effect of the initial temperature variation. © 2012 Elsevier Ltd. All rights reserved.

  4. Systems and processes for conversion of ethylene feedstocks to hydrocarbon fuels

    Energy Technology Data Exchange (ETDEWEB)

    Lilga, Michael A.; Hallen, Richard T.; Albrecht, Karl O.; Cooper, Alan R.; Frye, John G.; Ramasamy, Karthikeyan Kallupalayam

    2017-05-30

    Systems, processes, and catalysts are disclosed for obtaining fuel and fuel blends containing selected ratios of open-chain and closed-chain fuel-range hydrocarbons suitable for production of alternate fuels including gasolines, jet fuels, and diesel fuels. Fuel-range hydrocarbons may be derived from ethylene-containing feedstocks and ethanol-containing feedstocks.

  5. Interstellar Antifreeze: Ethylene Glycol

    Science.gov (United States)

    Hollis, J. M.; Lovas, F. J.; Jewell, P. R.; Coudert, L. H.

    2002-01-01

    Interstellar ethylene glycol (HOCH2CH2,OH) has been detected in emission toward the Galactic center source Sagittarius B2(N-LMH) by means of several millimeter-wave rotational torsional transitions of its lowest energy conformer. The types and kinds of molecules found to date in interstellar clouds suggest a chemistry that favors aldehydes and their corresponding reduced alcohols-e.g., formaldehyde (H2CO)/methanol (CH3OH), acetaldehyde (CH3CHO)/ethanol (CH3CH2OH). Similarly, ethylene glycol is the reduced alcohol of glycolaldehyde (CH2OHCHO), which has also been detected toward Sgr B2(N-LMH). While there is no consensus as to how any such large complex molecules are formed in the interstellar clouds, atomic hydrogen (H) and carbon monoxide (CO) could form formaldehyde on grain surfaces, but such surface chemistry beyond that point is uncertain. However, laboratory experiments have shown that the gas-phase reaction of atomic hydrogen (H) and solid-phase CO at 10-20 K can produce formaldehyde and methanol and that alcohols and other complex molecules can be synthesized from cometary ice analogs when subject to ionizing radiation at 15 K. Thus, the presence of aldehyde/ reduced alcohol pairs in interstellar clouds implies that such molecules are a product of a low-temperature chemistry on grain surfaces or in grain ice mantles. This work suggests that aldehydes and their corresponding reduced alcohols provide unique observational constraints on the formation of complex interstellar molecules.

  6. Nonpremixed ignition, laminar flame propagation, and mechanism reduction of n-butanol, iso-butanol, and methyl butanoate

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Wei; Kelley, A. P.; Law, C. K.

    2011-01-01

    The non-premixed ignition temperature of n-butanol (CH{sub 3}CH{sub 2}CH{sub 2}CH{sub 2}OH), iso-butanol ((CH{sub 3}){sub 2}CHCH{sub 2}OH) and methyl butanoate (CH{sub 3}CH{sub 2}CH{sub 2}COOCH{sub 3}) was measured in a liquid pool assembly by heated oxidizer in a stagnation flow for system pressures of 1 and 3 atm. In addition, the stretch-corrected laminar flame speeds of mixtures of air–n-butanol/iso-butanol/methyl butanoate were determined from the outwardly propagating spherical flame at initial pressures of up to 2 atm, for an extensive range of equivalence ratio. The ignition temperature and laminar flame speeds of n-butanol and methyl butanoate were computationally simulated with three recently developed kinetic mechanisms in the literature. Dominant reaction pathways to ignition and flame propagation were identified and discussed through a chemical explosive mode analysis (CEMA) and sensitivity analysis. The detailed models were further reduced through a series of systematic strategies. The reduced mechanisms provided excellent agreement in both homogeneous and diffusive combustion environments and greatly improved the computation efficiency.

  7. Joint PDF Modelling of Local Extinction and Pollutant Formation in Non-premixed Turbulent Flames

    Science.gov (United States)

    Tang, Qing; Xu, Jun; Pope, Stephen B.

    2000-11-01

    A velocity-composition-turbulence frequency joint PDF approach is applied to model piloted methane/air turbulent diffusion flames investigated experimentally by Barlow and Frank. These flames exhibit an increasing amount of local extinction with increasing jet velocity, and are good cases to test the capabilities of turbulence-chemistry and combustion-chemistry models to account for local extinction and pollutant formation. In this study, the chemistry is an augmented reduced mechanism (19 species and 15 reaction steps) derived from the GRI2.11 detailed mechanism for methane oxidation by Sung and co-workers. The mechanism takes account of C2 chemistry, and the formation of oxides of nitrogen is treated by the inclusion of NO, NH3 and HCN. The turbulence models include the simplified Langevin model (SLM) for velocity, a stochastic model of Jayesh and Pope for turbulence frequency, the EMST model of Subramaniam and Pope for molecular mixing. The computational method for the solution of the modeled joint PDF equation features moving particles in a Lagrangian framework. The reaction calculations are performed via the in situ adaptive tabulation (ISAT) algorithm of Pope. The calculation results show good agreement with the experimental data, including the minor species NO and CO. The increase of local extinction (quantitatively characterized by a single variable - burning index) with increasing jet velocity is also accurately predicted by the calculations. It is founded that a small change of the inlet pilot temperature has a significant influence on the calculations and a systematic study has been made to investigate this sensitivity. For the flame with lowest velocity, the large influence is mainly observed close to the nozzle, while for the flame close to extinction, the calculated behavior is exquisitely sensitive to the pilot temperature, i.e., a 10K lower pilot temperature may cause global extinction.

  8. Ethylene oxide potential toxicity.

    Science.gov (United States)

    da Cunha Mendes, Gisela Cristina; da Silva Brandão, Teresa Ribeiro; Miranda Silva, Cristina Luisa

    2008-05-01

    The future of ethylene oxide (EO) sterilization has been questioned, owing to its associated toxicity. EO has been around for more than 60 years, mainly due to its recognized characteristics of reliability and effectiveness, coupled with the process flexibility, as well as its compatibility with most mechanical devices. Despite the well-known EO toxicity, the undesirable effects of medical devices' EO residues on the patient's health have not yet been well established. There are limitations related to the current risk-assessment studies. To overcome these drawbacks, demands on greater safety are increasing, which lead to improvements in sterilizers and aeration equipment, as well as the design of the processes. The paper under evaluation highlights risks related to EO sterilization of materials used during processing of stem cells for transplantation, but is an example of a study where the dose of the residues in the devices is not considered.

  9. Quantum Entropic Ambiguities: Ethylene

    CERN Document Server

    Balachandran, A P; Vaidya, S

    2013-01-01

    In a quantum system, there may be many density matrices associated with a state on an algebra of observables. For each density matrix, one can compute its entropy. These are in general different. Therefore one reaches the remarkable possibility that there may be many entropies for a given state [Private communication from R. Sorkin]. This ambiguity in entropy can often be traced to a gauge symmetry emergent from the non-trivial topological character of the configuration space of the underlying system. It can also happen in finite-dimensional matrix models. In the present work, we discuss this entropy ambiguity and its consequences for an ethylene molecule. This is a very simple and well-known system where these notions can be put to tests. Besides its intrinsic conceptual interest, the simplicity of this model can serve as an introduction to a similar discussion of systems such as coloured monopoles and the breaking of colour symmetry.

  10. Jet Quenching via Jet Collimation

    CERN Document Server

    Casalderrey-Solana, Jorge; Wiedemann, Urs Achim

    2011-01-01

    The ATLAS Collaboration recently reported strong modifications of dijet properties in heavy ion collisions. In this work, we discuss to what extent these first data constrain already the microscopic mechanism underlying jet quenching. Simple kinematic arguments lead us to identify a frequency collimation mechanism via which the medium efficiently trims away the soft components of the jet parton shower. Through this mechanism, the observed dijet asymmetry can be accomodated with values of $\\hat{q}\\, L$ that lie in the expected order of magnitude.

  11. Mortality among ethylene oxide workers.

    Science.gov (United States)

    Morgan, R W; Claxton, K W; Divine, B J; Kaplan, S D; Harris, V B

    1981-11-01

    Because of reports linking an increased risk of leukemia with exposure to ethylene oxide, a mortality study of workers with potential exposure to ethylene oxide at the Texaco Chemical Company Plant in Port Neches, Tex., was undertaken. A total of 767 males with potential exposure to ethylene oxide were identified. Forty-six deaths occurred in this cohort with 80 expected (standardized mortality ratio; SMR = 58). No deaths from leukemia were seen, nor were there any statistically significant excesses from any specific causes of death.

  12. Crystal structures of ethylene glycol and ethylene glycol monohydrate.

    Science.gov (United States)

    Fortes, A Dominic; Suard, Emmanuelle

    2011-12-21

    We have carried out a neutron powder diffraction study of deuterated ethylene glycol (1,2-ethanediol), and deuterated ethylene glycol monohydrate with the D2B high-resolution diffractometer at the Institut Laue-Langevin. Using these data, we have refined the complete structure, including all hydrogen atoms, of the anhydrous phase at 220 K. In addition, we have determined the structure of ethylene glycol monohydrate at 210 K using direct space methods. Anhydrous ethylene glycol crystallizes in space-group P2(1)2(1)2(1) with four formula units in a unit-cell of dimensions a = 5.0553(1) Å, b = 6.9627(1) Å, c = 9.2709(2) Å, and V = 326.319(8) Å(3) [ρ(calc)(deuterated) = 1386.26(3) kg m(-3)] at 220 K. Ethylene glycol monohydrate crystallizes in space-group P2(1)/c with four formula units in a unit-cell of dimensions a = 7.6858(3) Å, b = 7.2201(3) Å, c = 7.7356(4) Å, β = 92.868(3)°, and V = 428.73(2) Å(3) [ρ(calc)(deuterated) = 1365.40(7) kg m(-3)] at 210 K. Both the structures are characterized by the gauche conformation of the ethylene glycol molecule; however, the anhydrous phase contains the tGg' rotamer (or its mirror, g'Gt), whereas the monohydrate contains the gGg' rotamer. In the monohydrate, each water molecule is tetrahedrally coordinated, donating two hydrogen bonds to, and accepting two hydrogen bonds from the hydroxyl groups of neighboring ethylene glycol molecules. There are substantial differences in the degree of weak C-D···O hydrogen bonding between the two crystals, which calls into question the role of these interactions in determining the conformation of the ethylene glycol molecule.

  13. 46 CFR 154.1725 - Ethylene oxide.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Ethylene oxide. 154.1725 Section 154.1725 Shipping COAST....1725 Ethylene oxide. (a) A vessel carrying ethylene oxide must: (1) Have cargo piping, vent piping, and... space of an ethylene oxide cargo tank for a period of 30 days under the condition of paragraph (e) of...

  14. Dichotomy of Solar Coronal Jets: Standard Jets and Blowout Jets

    Science.gov (United States)

    Moore, R. L.; Cirtain, J. W.; Sterling, A. C.; Falconer, D. A.

    2010-01-01

    By examining many X-ray jets in Hinode/XRT coronal X-ray movies of the polar coronal holes, we found that there is a dichotomy of polar X-ray jets. About two thirds fit the standard reconnection picture for coronal jets, and about one third are another type. We present observations indicating that the non-standard jets are counterparts of erupting-loop H alpha macrospicules, jets in which the jet-base magnetic arch undergoes a miniature version of the blowout eruptions that produce major CMEs. From the coronal X-ray movies we present in detail two typical standard X-ray jets and two typical blowout X-ray jets that were also caught in He II 304 Angstrom snapshots from STEREO/EUVI. The distinguishing features of blowout X-ray jets are (1) X-ray brightening inside the base arch in addition to the outside bright point that standard jets have, (2) blowout eruption of the base arch's core field, often carrying a filament of cool (T 10(exp 4) - 10(exp 5) K) plasma, and (3) an extra jet-spire strand rooted close to the bright point. We present cartoons showing how reconnection during blowout eruption of the base arch could produce the observed features of blowout X-ray jets. We infer that (1) the standard-jet/blowout-jet dichotomy of coronal jets results from the dichotomy of base arches that do not have and base arches that do have enough shear and twist to erupt open, and (2) there is a large class of spicules that are standard jets and a comparably large class of spicules that are blowout jets.

  15. Inhibition of ethylene production by rhizobitoxine

    Energy Technology Data Exchange (ETDEWEB)

    Owens, L.D.; Lieberman, M.; Kunishi, A.

    1970-01-01

    Rhizobitoxine, an inhibitor of methionine biosynthesis in Salmonella typhimurium, inhibited ethylene production about 75% in light-grown sorghum seedlings and in senescent apple tissue. Ethylene production stimulated by indoleacetic acid and kinetin in sorghum was similarly inhibited. With both apple and sorghum, the inhibition could only be partially relieved by additions of methionine. A methionine analogue, ..cap alpha..-keto-..gamma..-methylthiobutyric acid, which has been suggested as an intermediate between methionine and ethylene, had no effect on the inhibition. Incorporation of /sup 14/C from added methionine-/sup 14/C into ethylene was curtailed by rhizobitoxine to about the same extent as was ethylene production. These results suggest that rhizobitoxine interferes with ethylene biosynthesis by blocking the conversion of methionine to ethylene and not indirectly by inhibiting the biosynthesis of methionine. Ethylene production by Penicillium digitatum, a fungus which produces ethylene via pathways not utilizing methionine as a precursor, was not affected by rhizobitoxine. 16 references, 2 figures, 4 tables.

  16. Investigation of non-premixed flame combustion characters in GO2/GH2 shear coaxial injectors using non-intrusive optical diagnostics

    Science.gov (United States)

    Dai, Jian; Yu, NanJia; Cai, GuoBiao

    2015-12-01

    Single-element combustor experiments are conducted for three shear coaxial geometry configuration injectors by using gaseous oxygen and gaseous hydrogen (GO2/GH2) as propellants. During the combustion process, several spatially and timeresolved non-intrusive optical techniques, such as OH planar laser induced fluorescence (PLIF), high speed imaging, and infrared imaging, are simultaneously employed to observe the OH radical concentration distribution, flame fluctuations, and temperature fields. The results demonstrate that the turbulent flow phenomenon of non-premixed flame exhibits a remarkable periodicity, and the mixing ratio becomes a crucial factor to influence the combustion flame length. The high speed and infrared images have a consistent temperature field trend. As for the OH-PLIF images, an intuitionistic local flame structure is revealed by single-shot instantaneous images. Furthermore, the means and standard deviations of OH radical intensity are acquired to provide statistical information regarding the flame, which may be helpful for validation of numerical simulations in future. Parameters of structure configurations, such as impinging angle and oxygen post thickness, play an important role in the reaction zone distribution. Based on a successful flame contour extraction method assembled with non-linear anisotropic diffusive filtering and variational level-set, it is possible to implement a fractal analysis to describe the fractal characteristics of the non-premixed flame contour. As a result, the flame front cannot be regarded as a fractal object. However, this turbulent process presents a self-similarity characteristic.

  17. Jet Car Track Site

    Data.gov (United States)

    Federal Laboratory Consortium — Located in Lakehurst, New Jersey, the Jet Car Track Site supports jet cars with J57 engines and has a maximum jet car thrust of 42,000 pounds with a maximum speed of...

  18. Sooting turbulent jet flame: characterization and quantitative soot measurements

    Science.gov (United States)

    Köhler, M.; Geigle, K. P.; Meier, W.; Crosland, B. M.; Thomson, K. A.; Smallwood, G. J.

    2011-08-01

    Computational fluid dynamics (CFD) modelers require high-quality experimental data sets for validation of their numerical tools. Preferred features for numerical simulations of a sooting, turbulent test case flame are simplicity (no pilot flame), well-defined boundary conditions, and sufficient soot production. This paper proposes a non-premixed C2H4/air turbulent jet flame to fill this role and presents an extensive database for soot model validation. The sooting turbulent jet flame has a total visible flame length of approximately 400 mm and a fuel-jet Reynolds number of 10,000. The flame has a measured lift-off height of 26 mm which acts as a sensitive marker for CFD model validation, while this novel compiled experimental database of soot properties, temperature and velocity maps are useful for the validation of kinetic soot models and numerical flame simulations. Due to the relatively simple burner design which produces a flame with sufficient soot concentration while meeting modelers' needs with respect to boundary conditions and flame specifications as well as the present lack of a sooting "standard flame", this flame is suggested as a new reference turbulent sooting flame. The flame characterization presented here involved a variety of optical diagnostics including quantitative 2D laser-induced incandescence (2D-LII), shifted-vibrational coherent anti-Stokes Raman spectroscopy (SV-CARS), and particle image velocimetry (PIV). Producing an accurate and comprehensive characterization of a transient sooting flame was challenging and required optimization of these diagnostics. In this respect, we present the first simultaneous, instantaneous PIV, and LII measurements in a heavily sooting flame environment. Simultaneous soot and flow field measurements can provide new insights into the interaction between a turbulent vortex and flame chemistry, especially since soot structures in turbulent flames are known to be small and often treated in a statistical manner.

  19. 湍流扩散火焰局部熄火和再燃现象的PDF模拟%PDF Modeling of Local Extinction and Re-ignition Within Turbulent Non-Premixed Flame

    Institute of Scientific and Technical Information of China (English)

    王海峰; 陈义良

    2004-01-01

    对一个值班湍流CH2/O2/N2射流扩散火焰(Sandia Flame D)进行了数值模拟研究.所采用的数学物理模型包括双尺度的k-ε湍流模型,标量联合的概率密度函数(PDF)输运方程方法,甲烷氧化的ARM简化化学反应机理(包含16种组分,12步总包反应)和欧几里德最小生成树(EMST)小尺度混合模型.将计算结果和实验数据进行了比较,不仅对于平均量,对于标量的散点分布和条件概率密度分布也是如此.计算结果表明文中采用的模型不仅能够预测宏观的火焰结构,而且预测了湍流燃烧中复杂的局部熄火和再燃过程.%A piloted CH4/O2/N2 turbulent jet non-premixed flame(Sandia flame D)is numerically investigated. The summary of the adopted models contains a two-scale k - ε turbulence model, the scalar joint probability density function (PDF) transport equation approach, the augmented reduced mechanism(ARM)for methane oxidation (consisting of 16 species and 12 lumped reaction steps), the Euclidean minimum spanning tree (EMST)small scale mixing model etc. The agreements between the numerical results and the experimental data are good, including the scatter plots and conditional PDFs of scalars as well as the scalar averages.The numerical results indicate that the present models are not only able to represent the macro flame structure accurately, but also can successfully predict the complicated local extinction and re-ignition processes in the turbulent combustion.

  20. Development of Prototype Laboratory Setup for Selective Detection of Ethylene Based on Multiwalled Carbon Nanotubes

    Directory of Open Access Journals (Sweden)

    J. Kathirvelan

    2014-01-01

    Full Text Available We report here a prototype laboratory setup for detecting ethylene (C2H4 in ppm level employing a sensor made of multiwalled carbon nanotubes of 40 nm average tube diameter. The proposed reversible chemoresistive ethylene sensor is fabricated using Kapton as the substrate onto which carbon nanotubes are coated using thick film technology. IDT silver electrodes are printed using piezo head based ink-jet printing technology. The increases in electrical resistance of the sensor element are measured on exposure to ethylene for different ethylene concentrations using a potentiostat and data acquisition system. The increase in resistance of the calibrated sensor element on exposure to ethylene (analyte is about 18.4% at room temperature for 50 ppm ethylene concentration. This change is reversible. Our sensor element exhibits a better performance than those reported earlier (1.8% and it has got the rise and fall time of 10 s and 60 s, respectively. It could be used for testing the ripening of fruits.

  1. Inclusive Jets in PHP

    Science.gov (United States)

    Roloff, P.

    Differential inclusive-jet cross sections have been measured in photoproduction for boson virtualities Q^2 < 1 GeV^2 with the ZEUS detector at HERA using an integrated luminosity of 300 pb^-1. Jets were identified in the laboratory frame using the k_T, anti-k_T or SIScone jet algorithms. Cross sections are presented as functions of the jet pseudorapidity, eta(jet), and the jet transverse energy, E_T(jet). Next-to-leading-order QCD calculations give a good description of the measurements, except for jets with low E_T(jet) and high eta(jet). The cross sections have the potential to improve the determination of the PDFs in future QCD fits. Values of alpha_s(M_Z) have been extracted from the measurements based on different jet algorithms. In addition, the energy-scale dependence of the strong coupling was determined.

  2. Influence of Pilot Flame Parameters on the Stability of Turbulent Jet Flames

    KAUST Repository

    Guiberti, Thibault F.

    2016-11-08

    This paper presents a comprehensive study of the effects of pilot parameters on flame stability in a turbulent jet flame. The Sydney inhomogeneous piloted burner is employed as the experimental platform with two main fuels, namely, compressed natural gas and liquefied petroleum gas. Various concentrations of five gases are used in the pilot stream, hydrogen, acetylene, oxygen, nitrogen, and argon, to enable a sufficient range in exploring the following parameters: pilot heat release, temperature, burnt gas velocity, equivalence ratio, and H/C ratio. The experimental results are mainly presented in the form of blow-off limits and supported by simple calculations, which simulate various conditions of the pilot–mixture interface. It is found that increasing the pilot adiabatic flame temperature benefits the flame stability and has an even greater influence than the heat release, which is also known to enhance the blow-off limits. Conversely, increasing the pilot burnt gas velocity reduces the blow-off velocity, except for the limiting case when the jet is fully non-premixed. The H/C ratio has negligible effects, while resorting to lean pilots significantly increases the stability of globally rich partially premixed and premixed jets. Such findings are consistent with trends obtained from laminar flame calculations for rich fuel/air mixtures issuing against hot combustion products to simulate the pilot stream.

  3. RESIDUAL RISK ASSESSMENT: ETHYLENE OXIDE ...

    Science.gov (United States)

    This document describes the residual risk assessment for the Ethylene Oxide Commercial Sterilization source category. For stationary sources, section 112 (f) of the Clean Air Act requires EPA to assess risks to human health and the environment following implementation of technology-based control standards. If these technology-based control standards do not provide an ample margin of safety, then EPA is required to promulgate addtional standards. This document describes the methodology and results of the residual risk assessment performed for the Ethylene Oxide Commercial Sterilization source category. The results of this analyiss will assist EPA in determining whether a residual risk rule for this source category is appropriate.

  4. Colorometric detection of ethylene glycol vapor

    Science.gov (United States)

    Helm, C.; Mosier, B.; Verostko, C. E.

    1970-01-01

    Very low concentrations of ethylene glycol in air or other gases are detected by passing a sample through a glass tube with three partitioned compartments containing reagents which successively convert the ethylene glycol vapor into a colored compound.

  5. 49 CFR 173.323 - Ethylene oxide.

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Ethylene oxide. 173.323 Section 173.323... SHIPMENTS AND PACKAGINGS Gases; Preparation and Packaging § 173.323 Ethylene oxide. (a) For packaging ethylene oxide in non-bulk packagings, silver mercury or any of its alloys or copper may not be used in any...

  6. Liquid ethylene-propylene copolymers

    Science.gov (United States)

    Rhein, R. A.; Ingham, J. D.; Humphrey, M. F.

    1975-01-01

    Oligomers are prepared by heating solid ethylene-propylene rubber in container that retains solid and permits liquid product to flow out as it is formed. Molecular weight and viscosity of liquids can be predetermined by process temperature. Copolymers have low viscosity for given molecular weight.

  7. The Giant Jet

    Science.gov (United States)

    Neubert, T.; Chanrion, O.; Arnone, E.; Zanotti, F.; Cummer, S.; Li, J.; Füllekrug, M.; van der Velde, O.

    2012-04-01

    Thunderstorm clouds may discharge directly to the ionosphere in spectacular luminous jets - the longest electric discharges on our planet. The electric properties of jets, such as their polarity, conductivity, and currents, have been predicted by models, but are poorly characterized by measurements. Here we present an analysis of the first gigantic jet that with certainty has a positive polarity. The jet region in the mesosphere was illuminated by an unusual sprite discharge generated by a positive cloud-to-ground lightning flash shortly after the onset of the jet. The sprite appeared with elements in a ring at ~40 km distance around the jet, the elements pointing curving away from the jet. This suggests that the field close the jet partially cancels the field driving the sprite. From a simple model of the event we conclude that a substantial portion of the positive cloud potential must be carried to ~50 km altitude, which is also consistent with the observed channel expansion and the electromagnetic radiation associated with the jet. It is further shown that blue jets are likely to substantially modify the free electron content in the lower ionosphere because of increased electron attachment driven by the jet electric field. The model further makes clear the relationship between jets, gigantic jets, and sprites. This is the first time that sprites are used for sounding the properties of the mesosphere. The observations presented here will allow evaluation of theories for jet and gigantic jet generation and of their influence on the atmosphere-ionosphere system.

  8. Role of the outer-edge flame on flame extinction in nitrogen-diluted non-premixed counterflow flames with finite burner diameters

    KAUST Repository

    Chung, Yong Ho

    2013-03-01

    This study of nitrogen-diluted non-premixed counterflow flames with finite burner diameters investigates the important role of the outer-edge flame on flame extinction through experimental and numerical analyses. It explores flame stability diagrams mapping the flame extinction response of nitrogen-diluted non-premixed counterflow flames to varying global strain rates in terms of burner diameter, burner gap, and velocity ratio. A critical nitrogen mole fraction exists beyond which the flame cannot be sustained; the critical nitrogen mole fraction versus global strain rate curves have C-shapes for various burner diameters, burner gaps, and velocity ratios. At sufficiently high strain-rate flames, these curves collapse into one curve; therefore, the flames follow the one-dimensional flame response of a typical diffusion flame. Low strain-rate flames are significantly affected by radial conductive heat loss, and therefore flame length. Three flame extinction modes are identified: flame extinction through shrinkage of the outer-edge flame with or without oscillations at the outer-edge flame prior to the extinction, and flame extinction through a flame hole at the flame center. The extinction modes are significantly affected by the behavior of the outer-edge flame. Detailed explanations are provided based on the measured flame-surface temperature and numerical evaluation of the fractional contribution of each term in the energy equation. Radial conductive heat loss at the flame edge to ambience is the main mechanism of extinction through shrinkage of the outer-edge flame in low strain-rate flames. Reduction of the burner diameter can extend the flame extinction mode by shrinking the outer-edge flame in higher strain-rate flames. © 2012 Elsevier Ltd. All rights reserved.

  9. ETHYLENE OXIDE-ETHYLENE TEREPHTHALATE SEGMENTED COPOLYMER SOLID ELECTROLYTE

    Institute of Scientific and Technical Information of China (English)

    LUO Xiaolie; WANG Chuanqing; WANG Haiqian; HU Keliang; MA Dezhu

    1994-01-01

    A series of ethylene oxide-ethylene terephthalate segmented copolymers (EOET) were synthesized and complexed with LiClO4 to form some new polymer electrolytes. The EOET-LiClO4 electrolytes exhibit not only high ionic conductivity, but also good mechanical strength and toughness. The EOET 3400-25-LiClO4 complex possesses the highest conductivity (4. 65 ×10-5s·cm-1)at room temperature when the ratio [Li+]/[EO] equals 1/16.The structures of these electrolytes were examined with FTIR analysis, X-ray diffraction and DSC thermograms, and the results of high ionic conductivity of the segmented copolymers were discussed.

  10. Drying poly(ethylene glycol)

    OpenAIRE

    sprotocols

    2015-01-01

    Authors: Lucas Kinard, Kurtis Kasper & Antonios Mikos ### Abstract This protocol describes the drying of poly(ethylene glycol) (PEG) by a simple 6 step procedure. One can implement this protocol using common lab glass and lab equipment. Water is removed from PEG by azeotropic distillation in toluene. The two components are mixed and toluene and water are distilled off by heating the solution to 170°C. This procedure can be implemented in ~2 h. ### Introduction In many ...

  11. Study of Water Jet Impulse in Water-Jet Looms

    Institute of Scientific and Technical Information of China (English)

    LI Ke-rang; MA Wei-wei; CHEN Ming

    2005-01-01

    The water jet impulse is brought forward to study the traction force of the water jet to the flying weft in water-jet looms. The distribution of the water jet impulse in the shed is tested by a sensor, and the influence of water jet parameters on the water jet impulse is analyzed.

  12. Large Eddy Simulation of Autoignition in a Turbulent Hydrogen Jet Flame Using a Progress Variable Approach

    Directory of Open Access Journals (Sweden)

    Rohit Kulkarni

    2012-01-01

    Full Text Available The potential of a progress variable formulation for predicting autoignition and subsequent kernel development in a nonpremixed jet flame is explored in the LES (Large Eddy Simulation context. The chemistry is tabulated as a function of mixture fraction and a composite progress variable, which is defined as a combination of an intermediate and a product species. Transport equations are solved for mixture fraction and progress variable. The filtered mean source term for the progress variable is closed using a probability density function of presumed shape for the mixture fraction. Subgrid fluctuations of the progress variable conditioned on the mixture fraction are neglected. A diluted hydrogen jet issuing into a turbulent coflow of preheated air is chosen as a test case. The model predicts ignition lengths and subsequent kernel growth in good agreement with experiment without any adjustment of model parameters. The autoignition length predicted by the model depends noticeably on the chemical mechanism which the tabulated chemistry is based on. Compared to models using detailed chemistry, significant reduction in computational costs can be realized with the progress variable formulation.

  13. Gradient trajectory analysis of the scalar superlayer in a jet flow

    Science.gov (United States)

    Gampert, Markus; Schaefer, Philip; Peters, Norbert

    2012-11-01

    Based on planar high-speed Rayleigh scattering measurements of the mass fraction of propane discharging from a turbulent round jet into co-flowing carbon dioxide at nozzle based Reynolds numbers Re0 = 3 , 000 - 8 , 600 , we investigate the scalar superlayer. The latter is located between the fully turbulent part of the jet and the outer flow and has the so called turbulent/non-turbulent interface embedded within it. It is termed in analogy to the laminar superlayer introduced by Corrsin and Kistler (NACA Report 1244, 1955). Using scalar gradient trajectories, we partition the turbulent scalar field into the afore mentioned three regions according to an approach developed by Mellado et al. (J. Fluid Mech. 626:333-365, 2009) based on which we in a next step investigate conditioned zonal statistics of the scalar pdf as well as the scalar difference along the trajectory and its mean scalar value. Finally, we relate our results for the scalar superlayer on the one hand to the findings made in other experimental and numerical studies of the turbulent/non-turbulent interface and discuss them on the other hand in the context of the flamelet approach in turbulent non-premixed combustion. This work was funded by the Cluster of Excellence ``Tailor-Made Fuels from Biomass,'' which is funded by the Excellence Initiative of the German federal state governments to promote science and research at German universities.

  14. Ethylene tetrafluoroethylene nanofibers prepared by CO2 laser supersonic drawing

    Directory of Open Access Journals (Sweden)

    A. Suzuki

    2013-06-01

    Full Text Available Ethylene tetrafluoroethylene (ETFE nanofibers were prepared by carbon dioxide (CO2 laser irradiation of asspun ETFE fibers with four different melt flow rates (MFRs in a supersonic jet that was generated by blowing air into a vacuum chamber through the fiber injection orifice. The drawability and superstructure of fibers produced by CO2 laser supersonic drawing depend on the laser power, the chamber pressure, the fiber injection speed, and the MFR. Nanofibers obtained using a laser power of 20 W, a chamber pressure of 20 kPa, and an MFR of 308 g•10 min–1 had an average diameter of 0.303 µm and a degree of crystallinity of 54%.

  15. Ethylene Glycol Metabolism by Pseudomonas putida

    OpenAIRE

    Mückschel, Björn; Simon, Oliver; Klebensberger, Janosch; Graf, Nadja; Rosche, Bettina; Altenbuchner, Josef; Pfannstiel, Jens; Huber, Armin; Hauer, Bernhard

    2012-01-01

    In this study, we investigated the metabolism of ethylene glycol in the Pseudomonas putida strains KT2440 and JM37 by employing growth and bioconversion experiments, directed mutagenesis, and proteome analysis. We found that strain JM37 grew rapidly with ethylene glycol as a sole source of carbon and energy, while strain KT2440 did not grow within 2 days of incubation under the same conditions. However, bioconversion experiments revealed metabolism of ethylene glycol by both strains, with the...

  16. Autoignition characteristics of laminar lifted jet flames of pre-vaporized iso-octane in heated coflow air

    KAUST Repository

    Alnoman, Saeed

    2015-12-01

    The stabilization characteristics of laminar non-premixed jet flames of pre-vaporized iso-octane, one of the primary reference fuels for octane rating, have been studied experimentally in heated coflow air. Non-autoignited and autoignited lifted flames were analyzed. With the coflow air at relatively low initial temperatures below 940 K, an external ignition source was required to stabilize the flame. These lifted flames had tribrachial edge structures and their liftoff heights correlated well with the jet velocity scaled by stoichiometric laminar burning velocity, indicating the importance of the edge propagation speed on flame stabilization. At high initial temperatures over 940 K, the autoignited flames were stabilized without requiring an external ignition source. These autoignited lifted flames exhibited either tribrachial edge structures or mild combustion behaviors depending on the level of fuel dilution. Two distinct transition behaviors were observed in the autoignition regime from a nozzle-attached flame to a lifted tribrachial-edge flame and then to lifted mild combustion as the jet velocity increased at a certain fuel dilution level. The liftoff data of the autoignited flames with tribrachial edges were analyzed based on calculated ignition delay times. Analysis of the experimental data suggested that ignition delay time may be much less sensitive to initial temperature under atmospheric pressure conditions as compared with predictions. © 2015 Elsevier Ltd. All rights reserved.

  17. Biocatalytic conversion of ethylene to ethylene oxide using an engineered toluene monooxygenase

    Energy Technology Data Exchange (ETDEWEB)

    Carlin, DA; Bertolani, SJ; Siegel, JB

    2015-01-01

    Mutants of toluene o-xylene monooxygenase are demonstrated to oxidize ethylene to ethylene oxide in vivo at yields of >99%. The best mutant increases ethylene oxidation activity by >5500-fold relative to the native enzyme. This is the first report of a recombinant enzyme capable of carrying out this industrially significant chemical conversion.

  18. Biocatalytic conversion of ethylene to ethylene oxide using an engineered toluene monooxygenase.

    Science.gov (United States)

    Carlin, D A; Bertolani, S J; Siegel, J B

    2015-02-11

    Mutants of toluene o-xylene monooxygenase are demonstrated to oxidize ethylene to ethylene oxide in vivo at yields of >99%. The best mutant increases ethylene oxidation activity by >5500-fold relative to the native enzyme. This is the first report of a recombinant enzyme capable of carrying out this industrially significant chemical conversion.

  19. Poly(ethylene oxide) functionalization

    Energy Technology Data Exchange (ETDEWEB)

    Pratt, Russell Clayton

    2014-04-08

    A simple procedure is provided by which the hydroxyl termini of poly(ethylene oxide) can be appended with functional groups to a useful extent by reaction and precipitation. The polymer is dissolved in warmed toluene, treated with an excess of organic base and somewhat less of an excess of a reactive acylating reagent, reacted for several hours, then precipitated in isopropanol so that the product can be isolated as a solid, and salt byproducts are washed away. This procedure enables functionalization of the polymer while not requiring laborious purification steps such as solvent-solvent extraction or dialysis to remove undesirable side products.

  20. Jet substructure in ATLAS

    CERN Document Server

    Miller, David W

    2011-01-01

    Measurements are presented of the jet invariant mass and substructure in proton-proton collisions at $\\sqrt{s} = 7$ TeV with the ATLAS detector using an integrated luminosity of 37 pb$^{-1}$. These results exercise the tools for distinguishing the signatures of new boosted massive particles in the hadronic final state. Two "fat" jet algorithms are used, along with the filtering jet grooming technique that was pioneered in ATLAS. New jet substructure observables are compared for the first time to data at the LHC. Finally, a sample of candidate boosted top quark events collected in the 2010 data is analyzed in detail for the jet substructure properties of hadronic "top-jets" in the final state. These measurements demonstrate not only our excellent understanding of QCD in a new energy regime but open the path to using complex jet substructure observables in the search for new physics.

  1. Effect of added polymer in free jets of a dilute polymer solution

    Science.gov (United States)

    Renoult, Marie-Charlotte; Charpentier, Jean-Baptiste; Crumeyrolle, Olivier; Mutabazi, Innocent

    2016-11-01

    The instability of a free viscoelastic jet is experimentally investigated by extruding an aqueous solution containing five parts per million of Poly(ethylene oxide) into air from a sixty micrometers orifice at relative low speeds. A method of image analysis was developed to quantify the effect of the added polymer on the morphology and the stability of the jet breakup. Three main representations were considered: the area versus perimeter relation for all liquid objects detected on the images, i.e. jets and jet fragments, the equivalent diameter distribution of jet fragments and the standard deviation curve of jets profiles. The former two provide information on the morphology of jet fragments: distinction of two classes, products and residues, and existence of coalescence. The latter gives information on the jet breakup stability: measurement of the growth rate and initial amplitude of the jet instability and detection of beads-on-a-string structures in the jet interface deformation. Experimental results will be presented and compared to theory.

  2. Turbulent buoyant jets and plumes

    CERN Document Server

    Rodi, Wolfgang

    The Science & Applications of Heat and Mass Transfer: Reports, Reviews, & Computer Programs, Volume 6: Turbulent Buoyant Jets and Plumes focuses on the formation, properties, characteristics, and reactions of turbulent jets and plumes. The selection first offers information on the mechanics of turbulent buoyant jets and plumes and turbulent buoyant jets in shallow fluid layers. Discussions focus on submerged buoyant jets into shallow fluid, horizontal surface or interface jets into shallow layers, fundamental considerations, and turbulent buoyant jets (forced plumes). The manuscript then exami

  3. 29 CFR 1926.1147 - Ethylene oxide.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 8 2010-07-01 2010-07-01 false Ethylene oxide. 1926.1147 Section 1926.1147 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... Ethylene oxide. Note: The requirements applicable to construction work under this section are identical to...

  4. 29 CFR 1915.1047 - Ethylene oxide.

    Science.gov (United States)

    2010-07-01

    ... 29 Labor 7 2010-07-01 2010-07-01 false Ethylene oxide. 1915.1047 Section 1915.1047 Labor Regulations Relating to Labor (Continued) OCCUPATIONAL SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR... § 1915.1047 Ethylene oxide. Note: The requirements applicable to shipyard employment under this section...

  5. Ethylene: A tiny molecule with great potential

    NARCIS (Netherlands)

    Woltering, E.J.; Vrije, de T.

    1995-01-01

    Ethylene (C2H4) is a gaseous plant hormone produced by higher and lower (green) plants and, when grown on appropriate substrates, also by fungi, yeasts and bacteria. Ethylene is involved in many developmental processes in plants and is biologically active in trace amounts (10-100 nl/l of air) that m

  6. Serum Calcium Concentration in Ethylene Glycol Poisoning.

    Science.gov (United States)

    Hodgman, Michael; Marraffa, Jeanna M; Wojcik, Susan; Grant, William

    2017-06-01

    The diagnosis of ethylene glycol intoxication can be challenging. Definitive testing for ethylene glycol is not readily available and clinical decisions are often based on clinical suspicion and the results of more readily available tests. One of these findings is hypocalcemia, presumable through complexation with the ethylene glycol metabolite oxalate. We performed a retrospective review of all patients admitted to a tertiary care hospital between 2005 and 2013 with laboratory confirmed ethylene glycol intoxication. Serum calcium on presentation was compared to blood gas pH on presentation as well as presentation serum bicarbonate. We did not find any relationship between calcium and serum pH either by linear regression or when dichotomized by pH ≥ or ethylene glycol poisoning, even in acidotic patients.

  7. Jet Substructure Without Trees

    Energy Technology Data Exchange (ETDEWEB)

    Jankowiak, Martin; Larkoski, Andrew J.; /SLAC /Stanford U., ITP

    2011-08-19

    We present an alternative approach to identifying and characterizing jet substructure. An angular correlation function is introduced that can be used to extract angular and mass scales within a jet without reference to a clustering algorithm. This procedure gives rise to a number of useful jet observables. As an application, we construct a top quark tagging algorithm that is competitive with existing methods. In preparation for the LHC, the past several years have seen extensive work on various aspects of collider searches. With the excellent resolution of the ATLAS and CMS detectors as a catalyst, one area that has undergone significant development is jet substructure physics. The use of jet substructure techniques, which probe the fine-grained details of how energy is distributed in jets, has two broad goals. First, measuring more than just the bulk properties of jets allows for additional probes of QCD. For example, jet substructure measurements can be compared against precision perturbative QCD calculations or used to tune Monte Carlo event generators. Second, jet substructure allows for additional handles in event discrimination. These handles could play an important role at the LHC in discriminating between signal and background events in a wide variety of particle searches. For example, Monte Carlo studies indicate that jet substructure techniques allow for efficient reconstruction of boosted heavy objects such as the W{sup {+-}} and Z{sup 0} gauge bosons, the top quark, and the Higgs boson.

  8. TASI Lectures on Jet Substructure

    CERN Document Server

    Shelton, Jessie

    2013-01-01

    Jet physics is a rich and rapidly evolving field, with many applications to physics in and beyond the Standard Model. These notes, based on lectures delivered at the June 2012 Theoretical Advanced Study Institute, provide an introduction to jets at the Large Hadron Collider. Topics covered include sequential jet algorithms, jet shapes, jet grooming, and boosted Higgs and top tagging.

  9. Jet propagation and deceleration

    CERN Document Server

    Perucho, Manel

    2013-01-01

    Extragalactic jets in active galactic nuclei (AGN) are divided into two morphological types, namely Fanaroff-Riley I (FRI) and Fanaroff-Riley II (FRII). The former show decollimated structure at the kiloparsec scales and are thought to be decelerated by entrainment within the first kiloparsecs of evolution inside the host galaxy. The entrainment and deceleration can be, at least partly, due to the interaction of jets with stellar winds and gas clouds that enter in the jet as they orbit around the galactic centre. In this contribution, I review recent simulations to study the dynamic effect of entrainment from stellar winds in jets and the direct interaction of jets with gas clouds and stellar winds. I also briefly describe the importance of these interactions as a possible scenario of high-energy emission from extragalactic jets.

  10. What ignites optical jets?

    Energy Technology Data Exchange (ETDEWEB)

    Sebastian Jester

    2002-12-23

    The properties of radio galaxies and quasars with and without optical or X-ray jets are compared. The majority of jets from which high-frequency emission has been detected so far (13 with optical emission, 11 with X-rays, 13 with both) are associated with the most powerful radio sources at any given redshift. It is found that optical/X-ray jet sources are more strongly beamed than the average population of extragalactic radio sources. This suggests that the detection or non-detection of optical emission from jets has so far been dominated by surface brightness selection effects, not by jet physics. It implies that optical jets are much more common than is currently appreciated.

  11. Mini-Jet Controlled Turbulent Round Air Jet

    Institute of Scientific and Technical Information of China (English)

    杜诚; 米建春; 周裕; 詹杰

    2011-01-01

    We report an investigation of the active control of a round air jet by multiple radial blowing mini-jets.The Reynolds number based on the jet exit velocity and diameter is 8000.It is found that once the continuous minijets are replaced with pulsed ones,the centerline velocity decay rate K can be greatly increased as the pulsing frequency of mini-jets approaches the natural vortex frequency of the main jet.For example,the K value is amplified by more than 50% with two(or four)pulsed mini-jets blowing,compared with the continuous mini-jets at the same ratio of the mass flow rate of the mini-jets to that of the main jet.%We report an investigation of the active control of a round air jet by multiple radial blowing mini-jets. The Reynolds number based on the jet exit velocity and diameter is 8000. It is found that once the continuous mini-jets are replaced with pulsed ones, the centerline velocity decay rate K can be greatly increased as the pulsing frequency of mini-jets approaches the natural vortex frequency of the main jet. For example, the K value is amplified by more than 50% with two (or four) pulsed mini-jets blowing, compared with the continuous mini-jets at the same ratio of the mass Sow rate of the mini-jets to that of the main jet.

  12. Hotspots, Jets and Environments

    Science.gov (United States)

    Hardcastle, M. J.

    2008-06-01

    I discuss the nature of `hotspots' and `jet knots' in the kpc-scale structures of powerful radio galaxies and their relationship to jet-environment interactions. I describe evidence for interaction between the jets of FRI sources and their local environments, and discuss its relationship to particle acceleration, but the main focus of the paper is the hotspots of FRIIs and on new observational evidence on the nature of the particle acceleration associated with them.

  13. Effects of non-unity Lewis number of gas-phase species in turbulent nonpremixed sooting flames

    KAUST Repository

    Attili, Antonio

    2016-02-13

    Turbulence statistics from two three-dimensional direct numerical simulations of planar n-heptane/air turbulent jets are compared to assess the effect of the gas-phase species diffusion model on flame dynamics and soot formation. The Reynolds number based on the initial jet width and velocity is around 15, 000, corresponding to a Taylor scale Reynolds number in the range 100 ≤ Reλ ≤ 150. In one simulation, multicomponent transport based on a mixture-averaged approach is employed, while in the other the gas-phase species Lewis numbers are set equal to unity. The statistics of temperature and major species obtained with the mixture-averaged formulation are very similar to those in the unity Lewis number case. In both cases, the statistics of temperature are captured with remarkable accuracy by a laminar flamelet model with unity Lewis numbers. On the contrary, a flamelet with a mixture-averaged diffusion model, which corresponds to the model used in the multi-component diffusion three-dimensional DNS, produces significant differences with respect to the DNS results. The total mass of soot precursors decreases by 20-30% with the unity Lewis number approximation, and their distribution is more homogeneous in space and time. Due to the non-linearity of the soot growth rate with respect to the precursors\\' concentration, the soot mass yield decreases by a factor of two. Being strongly affected by coagulation, soot number density is not altered significantly if the unity Lewis number model is used rather than the mixture-averaged diffusion. The dominant role of turbulent transport over differential diffusion effects is expected to become more pronounced for higher Reynolds numbers. © 2016 The Combustion Institute.

  14. Ethylene-dependent/ethylene-independent ABA regulation of tomato plants colonized by arbuscular mycorrhiza fungi.

    Science.gov (United States)

    Martín-Rodríguez, José Ángel; León-Morcillo, Rafael; Vierheilig, Horst; Ocampo, Juan Antonio; Ludwig-Müller, Jutta; García-Garrido, José Manuel

    2011-04-01

    We investigated the relationship between ABA and ethylene regulating the formation of the arbuscular mycorrhiza (AM) symbiosis in tomato (Solanum lycopersicum) plants and tried to define the specific roles played by each of these phytohormones in the mycorrhization process. We analysed the impact of ABA biosynthesis inhibition on mycorrhization by Glomus intraradices in transgenic tomato plants with an altered ethylene pathway. We also studied the effects on mycorrhization in sitiens plants treated with the aminoethoxyvinyl glycine hydrochloride (AVG) ethylene biosynthesis inhibitor and supplemented with ABA. In addition, the expression of plant and fungal genes involved in the mycorrhization process was studied. ABA biosynthesis inhibition qualitatively altered the parameters of mycorrhization in accordance with the plant's ethylene perception and ethylene biosynthesis abilities. Inhibition of ABA biosynthesis in wild-type plants negatively affected all the mycorrhization parameters studied, while tomato mutants impaired in ethylene synthesis only showed a reduced arbuscular abundance in mycorrhizal roots. Inhibition of ethylene synthesis in ABA-deficient sitiens plants increased the intensity of mycorrhiza development, while ABA application rescued arbuscule abundance in the root's mycorrhizal zones. The results of our study show an antagonistic interaction between ABA and ethylene, and different roles of each of the two hormones during AM formation. This suggests that a dual ethylene-dependent/ethylene-independent mechanism is involved in ABA regulation of AM formation. © 2011 The Authors. New Phytologist © 2011 New Phytologist Trust.

  15. Properties of gluon jets

    Energy Technology Data Exchange (ETDEWEB)

    Sugano, K.

    1986-09-01

    The properties of gluon jets are reviewed from an experimental point of view. The measured characteristics are compared to theoretical expectations. Although neither data nor models for the gluon jets are in the mature stage, there are remarkable agreements and also intriguing disagreements between experiment and theory. Since much interesting data have begun to emerge from various experiments and the properties of gluon jets are deeply rooted in the basic structure of non-Abelian gauge theory, the study of gluon jets casts further light on our understanding of QCD. Finally, the future prospects are discussed.

  16. The hydrogen laminar jet

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez-Sanz, M. [Departamento de Motopropulsion y Termofluidomecanica, ETSI Aeronauticos, Universidad Politecnica de Madrid, 28040 Madrid (Spain); Rosales, M. [Department Ingenieria Termica y de Fluidos, Universidad Carlos III de Madrid, 28911, Leganes (Spain); Instituto de Innovacion en Mineria y Metalurgia, Avenida del Valle 738, Santiago (Chile); Sanchez, A.L. [Department Ingenieria Termica y de Fluidos, Universidad Carlos III de Madrid, 28911, Leganes (Spain)

    2010-04-15

    Numerical and asymptotic methods are used to investigate the structure of the hydrogen jet discharging into a quiescent air atmosphere. The analysis accounts in particular for the variation of the density and transport properties with composition. The Reynolds number of the flow R{sub j}, based on the initial jet radius a, the density {rho}{sub j} and viscosity {mu}{sub j} of the jet and the characteristic jet velocity u{sub j}, is assumed to take moderately large values, so that the jet remains slender and stable, and can be correspondingly described by numerical integration of the continuity, momentum and species conservation equations written in the boundary-layer approximation. The solution for the velocity and composition in the jet development region of planar and round jets, corresponding to streamwise distances of order R{sub j}a, is computed numerically, along with the solutions that emerge both in the near field and in the far field. The small value of the hydrogen-to-air molecular weight ratio is used to simplify the solution by considering the asymptotic limit of vanishing jet density. The development provides at leading-order explicit analytical expressions for the far-field velocity and hydrogen mass fraction that describe accurately the hydrogen jet near the axis. The information provided can be useful in particular to characterize hydrogen discharge processes from holes and cracks. (author)

  17. Ethylene and flower longevity in Alstroemeria: relationship between tepal senescence, abscission and ethylene biosynthesis.

    Science.gov (United States)

    Wagstaff, Carol; Chanasut, Usawadee; Harren, Frans J M; Laarhoven, Luc-Jan; Thomas, Brian; Rogers, Hilary J; Stead, Anthony D

    2005-03-01

    Senescence of floral organs is broadly divided into two groups: those that exhibit sensitivity to exogenous ethylene and those that do not. Endogenous ethylene production from the former group is via a well-characterized biochemical pathway and is either due to developmental or pollination-induced senescence. Many flowers from the order Liliales are characterized as ethylene-insensitive since they do not appear to produce endogenous ethylene, or respond to exogenous ethylene treatments, however, the majority of cases studied are wilting flowers, rather than those where life is terminated by perianth abscission. The role of ethylene in the senescence and abscission of Alstroemeria peruviana cv. Rebecca and cv. Samora tepals was previously unclear, with silver treatments recommended for delaying leaf rather than flower senescence. In the present paper the effects of exogenous ethylene, 2-chloroethylphosphonic acid (CEPA) and silver thiosulphate (STS) treatments on tepal senescence and abscission have been investigated. Results indicate that sensitivity to ethylene develops several days after flower opening such that STS only has a limited ability to delay tepal abscission. Detachment force measurements indicate that cell separation events are initiated after anthesis. Endogenous ethylene production was measured using laser photoacoustics and showed that Alstroemeria senesce independently of ethylene production, but that an extremely small amount of ethylene (0.15 nl flower(-1) h(-1)) is produced immediately prior to abscission. Investigation of the expression of genes involved in ethylene biosysnthesis by semi-quantitative RT-PCR indicated that transcriptional regulation is likely to be at the level of ACC oxidase, and that the timing of ACC oxidase gene expression is coincident with development of sensitivity to exogenous ethylene.

  18. Ethylene glycol metabolism by Pseudomonas putida.

    Science.gov (United States)

    Mückschel, Björn; Simon, Oliver; Klebensberger, Janosch; Graf, Nadja; Rosche, Bettina; Altenbuchner, Josef; Pfannstiel, Jens; Huber, Armin; Hauer, Bernhard

    2012-12-01

    In this study, we investigated the metabolism of ethylene glycol in the Pseudomonas putida strains KT2440 and JM37 by employing growth and bioconversion experiments, directed mutagenesis, and proteome analysis. We found that strain JM37 grew rapidly with ethylene glycol as a sole source of carbon and energy, while strain KT2440 did not grow within 2 days of incubation under the same conditions. However, bioconversion experiments revealed metabolism of ethylene glycol by both strains, with the temporal accumulation of glycolic acid and glyoxylic acid for strain KT2440. This accumulation was further increased by targeted mutagenesis. The key enzymes and specific differences between the two strains were identified by comparative proteomics. In P. putida JM37, tartronate semialdehyde synthase (Gcl), malate synthase (GlcB), and isocitrate lyase (AceA) were found to be induced in the presence of ethylene glycol or glyoxylic acid. Under the same conditions, strain KT2440 showed induction of AceA only. Despite this difference, the two strains were found to use similar periplasmic dehydrogenases for the initial oxidation step of ethylene glycol, namely, the two redundant pyrroloquinoline quinone (PQQ)-dependent enzymes PedE and PedH. From these results we constructed a new pathway for the metabolism of ethylene glycol in P. putida. Furthermore, we conclude that Pseudomonas putida might serve as a useful platform from which to establish a whole-cell biocatalyst for the production of glyoxylic acid from ethylene glycol.

  19. Root formation in ethylene-insensitive plants.

    Science.gov (United States)

    Clark, D G; Gubrium, E K; Barrett, J E; Nell, T A; Klee, H J

    1999-09-01

    Experiments with ethylene-insensitive tomato (Lycopersicon esculentum) and petunia (Petunia x hybrida) plants were conducted to determine if normal or adventitious root formation is affected by ethylene insensitivity. Ethylene-insensitive Never ripe (NR) tomato plants produced more below-ground root mass but fewer above-ground adventitious roots than wild-type Pearson plants. Applied auxin (indole-3-butyric acid) increased adventitious root formation on vegetative stem cuttings of wild-type plants but had little or no effect on rooting of NR plants. Reduced adventitious root formation was also observed in ethylene-insensitive transgenic petunia plants. Applied 1-aminocyclopropane-1-carboxylic acid increased adventitious root formation on vegetative stem cuttings from NR and wild-type plants, but NR cuttings produced fewer adventitious roots than wild-type cuttings. These data suggest that the promotive effect of auxin on adventitious rooting is influenced by ethylene responsiveness. Seedling root growth of tomato in response to mechanical impedance was also influenced by ethylene sensitivity. Ninety-six percent of wild-type seedlings germinated and grown on sand for 7 d grew normal roots into the medium, whereas 47% of NR seedlings displayed elongated tap-roots, shortened hypocotyls, and did not penetrate the medium. These data indicate that ethylene has a critical role in various responses of roots to environmental stimuli.

  20. Jet mass spectra in Higgs+one jet at NNLL

    Energy Technology Data Exchange (ETDEWEB)

    Jouttenus, Teppo T.; Stewart, Iain W. [Massachusetts Institute of Technology, Cambridge, MA (United States). Center for Theoretical Physics; Tackmann, Frank J. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Waalewijn, Wouter J. [California Univ., San Diego, La Jolla, CA (United States). Dept. of Physics

    2013-02-15

    The invariant mass of a jet is a benchmark variable describing the structure of jets at the LHC. We calculate the jet mass spectrum for Higgs plus one jet at the LHC at next-to-next-to-leading logarithmic (NNLL) order using a factorization formula. At this order, the cross section becomes sensitive to perturbation theory at the soft m{sup 2}{sub jet}/p{sup jet}{sub T} scale. Our calculation is exclusive and uses the 1-jettiness global event shape to implement a veto on additional jets. The dominant dependence on the jet veto is removed by normalizing the spectrum, leaving residual dependence from non-global logarithms depending on the ratio of the jet mass and jet veto variables. For our exclusive jet cross section these non-global logarithms are parametrically smaller than in the inclusive case, allowing us to obtain a complete NNLL result. Results for the dependence of the jet mass spectrum on the kinematics, jet algorithm, and jet size R are given. Using individual partonic channels we illustrate the difference between the jet mass spectra for quark and gluon jets. We also study the effect of hadronization and underlying event on the jet mass in Pythia. To highlight the similarity of inclusive and exclusive jet mass spectra, a comparison to LHC data is presented.

  1. Dynamics of Water Jet in Water Jet Looms

    Institute of Scientific and Technical Information of China (English)

    李克让; 陈明

    2001-01-01

    On the base of the study on dynamics of water jet in water jet looms, the parameters of water jet mechanism which affect the speed of water jet are analyzed and optimized. So the stability of the water jet can be improved to raise the speed of water jet as well as weft insertion rate and to enlarge the width of woven fabrics a lot. At the same time it also points out that to increase water jet speed and to prolong its affective jet time depend mainly on the accretion of spring rate (constant)of stiffness and the diminution of plunger's cross sectional area respectively.

  2. 46 CFR 151.50-12 - Ethylene oxide.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Ethylene oxide. 151.50-12 Section 151.50-12 Shipping... BULK LIQUID HAZARDOUS MATERIAL CARGOES Special Requirements § 151.50-12 Ethylene oxide. (a)(1) Ethylene... otherwise provided for in paragraph (a)(3) of this section. (2) Ethylene oxide shall be loaded at a...

  3. 21 CFR 880.6860 - Ethylene oxide gas sterilizer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ethylene oxide gas sterilizer. 880.6860 Section... Miscellaneous Devices § 880.6860 Ethylene oxide gas sterilizer. (a) Identification. An ethylene gas sterilizer is a nonportable device intended for use by a health care provider that uses ethylene oxide (ETO) to...

  4. 21 CFR 172.770 - Ethylene oxide polymer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene oxide polymer. 172.770 Section 172.770... CONSUMPTION Other Specific Usage Additives § 172.770 Ethylene oxide polymer. The polymer of ethylene oxide may... conditions. (a) It is the polymer of ethylene oxide having a minimum viscosity of 1,500 centipoises in a 1...

  5. The role of ethylene perception in plant disease resistance

    NARCIS (Netherlands)

    Geraats, Bart Peter Johan

    2003-01-01

    Ethylene is a plant hormone that is involved in responses of the plant to various stress situations, such as pathogen attack. The role of ethylene in plant-pathogen interactions seems to be diverse. Exposure of plants to ethylene can induce disease resistance, but treatment with ethylene during

  6. Faraday, Jets, and Sand

    NARCIS (Netherlands)

    Sandtke, M.; van der Meer, Roger M.; Versluis, Andreas Michel; Lohse, Detlef

    2003-01-01

    When a 6-mm layer of fine sand with an average grain size of 40 µm is poured into a cylindrical container and shaken vertically, thin jets are seen to emerge from an airy cloud of grains, almost like protuberances from the corona of the sun. A quasi two-dimensional setup reveals the jet-formation

  7. Ethylene Glycol and Metabolite Concentrations in Fatal Ethylene Glycol Poisonings.

    Science.gov (United States)

    Viinamäki, Jenni; Sajantila, Antti; Ojanperä, Ilkka

    2015-01-01

    Ethylene glycol (EG) is used in antifreeze and other industrial products. It metabolizes to glycolic acid (GA) and oxalic acid (OX) that cause metabolic acidosis and are mainly responsible for the toxicity of EG. During 2010-2014, EG or GA was found in 25 postmortem cases in Finland. Of these cases, 21 were classified as fatal EG poisonings and 3 were classified as methanol (MeOH) poisonings. In this study, we report the concentrations of EG and GA in postmortem blood and urine samples of fatal EG or mixed MeOH/EG poisonings. In the fatal EG poisonings, the median EG and GA concentrations were 0.87 and 1.6 g/L in blood and 4.3 and 5.3 g/L in urine. The median urine-blood ratios were 3.8 and 3.1 for EG and GA. These results warrant the use of urine as a primary matrix for screening. In EG positive cases, the quantification of both EG and GA in blood is crucial as GA concentration appears to best indicate a fatal poisoning with an approximate threshold of 1.5 g/L. The measurement of urinary OX does not offer much additional value to toxic alcohol screening as it may originate from varying dietary conditions. © The Author 2015. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  8. Jet propulsion without inertia

    CERN Document Server

    Spagnolie, Saverio E

    2010-01-01

    A body immersed in a highly viscous fluid can locomote by drawing in and expelling fluid through pores at its surface. We consider this mechanism of jet propulsion without inertia in the case of spheroidal bodies, and derive both the swimming velocity and the hydrodynamic efficiency. Elementary examples are presented, and exact axisymmetric solutions for spherical, prolate spheroidal, and oblate spheroidal body shapes are provided. In each case, entirely and partially porous (i.e. jetting) surfaces are considered, and the optimal jetting flow profiles at the surface for maximizing the hydrodynamic efficiency are determined computationally. The maximal efficiency which may be achieved by a sphere using such jet propulsion is 12.5%, a significant improvement upon traditional flagella-based means of locomotion at zero Reynolds number. Unlike other swimming mechanisms which rely on the presentation of a small cross section in the direction of motion, the efficiency of a jetting body at low Reynolds number increas...

  9. Contamination control by use of ethylene oxide

    Science.gov (United States)

    Stroud, R. H.; Lyle, R. G.

    1972-01-01

    The uses of ethylene oxide as a decontaminating agent for planetary quarantine related applications are reported. Aspects discussed include: applications and limitations, chemical and physical properties, germicidal activity, methods of applications, and effects on personnel.

  10. Nitrous Oxide Ethane Ethylene Engine Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The Nitrous Oxide Ethane-Ethylene (NEE) engine is a proposed technology designed to provide spacecraft with non-toxic non-cryogenic high-performance propulsion. With...

  11. Inert Reassessment Document for Ethylene Glycol

    Science.gov (United States)

    Ethylene Glycol has many uses and are also used as antifreeze and deicers, as solvents, humectants, as chemical intermediates in the synthesis of other chemicals, and as components of many products such as brake fluids, lubricants, inks,and lacquers.

  12. Ethylene oxide and Acetaldehyde in hot cores

    CERN Document Server

    Occhiogrosso, A; Herbst, E; Viti, S; Ward, M D; Price, S D; Brown, W A

    2014-01-01

    [Abridged] Ethylene oxide and its isomer acetaldehyde are important complex organic molecules because of their potential role in the formation of amino acids. Despite the fact that acetaldehyde is ubiquitous in the interstellar medium, ethylene oxide has not yet been detected in cold sources. We aim to understand the chemistry of the formation and loss of ethylene oxide in hot and cold interstellar objects (i) by including in a revised gas-grain network some recent experimental results on grain surfaces and (ii) by comparison with the chemical behaviour of its isomer, acetaldehyde. We test the code for the case of a hot core. The model allows us to predict the gaseous and solid ethylene oxide abundances during a cooling-down phase prior to star formation and during the subsequent warm-up phase. We can therefore predict at what temperatures ethylene oxide forms on grain surfaces and at what temperature it starts to desorb into the gas phase. The model reproduces the observed gaseous abundances of ethylene oxid...

  13. Simulations of Solar Jets

    Science.gov (United States)

    Kohler, Susanna

    2017-02-01

    Formation of a coronal jet from twisted field lines that have reconnected with the ambient field. The colors show the radial velocity of the plasma. [Adapted from Szente et al. 2017]How do jets emitted from the Suns surface contribute to its corona and to the solar wind? In a recent study, a team of scientists performed complex three-dimensional simulations of coronal jets to answer these questions.Small ExplosionsCoronal jets are relatively small eruptions from the Suns surface, with heights of roughly 100 to 10,000 km, speeds of 10 to 1,000 km/s, and lifetimes of a few minutes to around ten hours. These jets are constantly present theyre emitted even from the quiet Sun, when activity is otherwise low and weve observed them with a fleet of Sun-watching space telescopes spanning the visible, extreme ultraviolet (EUV), and X-ray wavelength bands.A comparison of simulated observations based on the authors model (left panels) to actual EUV and X-ray observations of jets (right panels). [Szente et al. 2017]Due to their ubiquity, we speculate that these jets might contribute to heating the global solar corona (which is significantly hotter than the surface below it, a curiosity known as the coronal heating problem). We can also wonder what role these jets might play in driving the overall solar wind.Launching a JetLed by Judit Szente (University of Michigan), a team of scientists has explored the impact of coronal jets on the global corona and solar wind with a series of numerical simulations. Szente and collaborators used three-dimensional, magnetohydrodynamic simulations that provide realistic treatment of the solar atmosphere, the solar wind acceleration, and the complexities of heat transfer throughout the corona.In the authors simulations, a jet is initiated as a magnetic dipole rotates at the solar surface, winding up field lines. Magnetic reconnection between the twisted lines and the background field then launches the jet from the dense and hot solar

  14. Temperature Distribution in Ethylene Pyrolyzer

    Institute of Scientific and Technical Information of China (English)

    蓝兴英; 高金森; 徐春明

    2003-01-01

    Abstract A good understanding of the detailed temperature distribution in the furnace plays an important role in the implementation of operation optimization and design improvement of ethylene pyrolyzer. Numerical simulation of the turbulent flow, combustion and heat transfer was carried out to investigate the temperature distribution in industrial furnace. Inhomogeneities of the flue-gas temperature distribution were observed in X, Y, and Z direction of the furnace from the simulated results. Along the height of the furnace, the average flue-gas temperature increased initially and decreased afterward, and reached its peak at the height of 5m. The reactor tube skin temperature varied not only along the height of the furnace, but also around the circumference of the tube. The heat flux profiles from the furnace towards the reactor tubes followed the shape of the average flue-gas temperature profile. The heat flux of the inlet tubes was constantly higher than that of the outlet tubes at the same height in the furnace.

  15. Jets and QCD

    Energy Technology Data Exchange (ETDEWEB)

    Ali, A. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Kramer, G. [Hamburg Univ. (Germany). II. Inst. fuer Theoretische Physik

    2010-12-15

    The observation of quark and gluon jets has played a crucial role in establishing Quantum Chromodynamics [QCD] as the theory of the strong interactions within the Standard Model of particle physics. The jets, narrowly collimated bundles of hadrons, reflect configurations of quarks and gluons at short distances. Thus, by analysing energy and angular distributions of the jets experimentally, the properties of the basic constituents of matter and the strong forces acting between them can be explored. In this review we summarise the properties of quark and gluon jets and the impact of their observation on Quantum Chromodynamics, primarily the discovery of the gluons as the carriers of the strong force. Focusing on these basic points, jets in e{sup +}e{sup -} collisions will be in the foreground of the discussion. In addition we will delineate the role of jets as tools for exploring other particle aspects in ep and pp/p anti p collisions - quark and gluon densities in protons, measurements of the QCD coupling, fundamental 2-2 quark/gluon scattering processes, but also the impact of jet decays of top quarks, and W{sup {+-}},Z bosons on the electroweak sector. The presentation to a large extent is formulated in a non-technical language with the intent to recall the significant steps historically and convey the significance of this field also to communities beyond high energy physics. (orig.)

  16. Solar coronal jets

    Science.gov (United States)

    Dobrzyck, D.

    The solar jets were first observed by SOHO instruments (EIT, LASCO, UVCS) during the previous solar minimum. They were small, fast ejections originating from flaring UV bright points within large polar coronal holes. The obtained data provided us with estimates of the jet plasma conditions, dynamics, evolution of the electron temperature and heating rate required to reproduce the observed ionization state. To follow the polar jets through the solar cycle a special SOHO Joint Observing Program (JOP 155) was designed. It involves a number of SOHO instruments (EIT, CDS, UVCS, LASCO) as well as TRACE. The coordinated observations have been carried out since April 2002. The data enabled to identify counterparts of the 1996-1998 solar minimum jets. Their frequency of several events per day appear comparable to the frequency from the previous solar minimum. The jets are believed to be triggered by field line reconnection between emerging magnetic dipole and pre-existing unipolar field. Existing models predict that the hot jet is formed together with another jet of a cool material. The particular goal of the coordinated SOHO and TRACE observations was to look for possible association of the hot and cool plasma ejections. Currently there is observational evidence that supports these models.

  17. Jets with Variable R

    CERN Document Server

    Krohn, David; Wang, Lian-Tao

    2009-01-01

    We introduce a new class of jet algorithms designed to return conical jets with a variable Delta R radius. A specific example, in which Delta R scales as 1/pT, proves particularly useful in capturing the kinematic features of a wide variety of hard scattering processes. We implement this Delta R scaling in a sequential recombination algorithm and test it by reconstructing resonance masses and kinematic endpoints. These test cases show 10-20% improvements in signal efficiency compared to fixed Delta R algorithms. We also comment on cuts useful in reducing continuum jet backgrounds.

  18. Ethylene Controls Autophosphorylation of the Histidine Kinase Domain in Ethylene Receptor ETR1

    Institute of Scientific and Technical Information of China (English)

    Jan Voet-van-Vormizeele; Georg Groth

    2008-01-01

    Perception of the phytohormone ethylene is accomplished by a small family of integral membrane receptors.In Arabidopsis,five ethylene receptor proteins are known,including ethylene resistant 1 (ETR1).The hydrophobic aminoterminal domain of these receptors contains the ethylene-binding site while the carboxyl-terminal part consists of a histidine kinase domain and a response regulator domain,which are well known elements found in bacterial two-component signaling.The soluble membrane-extrinsic carboxyl-terminal part of the receptor,which is likely to play an important role in signal transduction,showed intrinsic kinase activity when expressed and purified on its own.However,a correlation between signal input and autokinase activity was not established in these studies,as receptors were missing the transmembrane amino-terminal sensor domain.Thus,it is still unclear whether autophosphorylation occurs in response to perception of the ethylene signal.Here,we report on autophosphorylation studies of purified full-length ETR1.Autokinase activity of the purified receptor is controlled by ethylene or by ethylene agonists like the π-acceptor compound cyanide.In fact,both signal molecules were able to completely turn off the intrinsic kinase activity.Furthermore,the observed inhibition of autophosphorylation in ETR1 by both molecules could be prevented when the ethylene antagonist 1-methyl-cyclopropene (MCP) was applied.

  19. Measurements of Jets in ALICE

    CERN Document Server

    Nattrass, Christine

    2016-01-01

    The ALICE detector can be used for measurements of jets in pp , p Pb, and Pb–Pb collisions. Measurements of jets in pp collisions are consis- tent with expectations from perturbative calculations and jets in p Pb scale with the number of nucleon–nucleon collisions, indicating that cold nuclear matter effects are not observed for jets. Measurements in Pb–Pb collisions demonstrate suppression of jets relative to expectations from binary scaling to the equivalent number of nucleon–nucleon collisions

  20. Astrophysics: Cosmic jet engines

    Science.gov (United States)

    Young, Andy

    2010-02-01

    In some galaxies, matter falling onto a supermassive black hole is ejected in narrow jets moving at close to the speed of light. New observations provide insight into the workings of these cosmic accelerators.

  1. Jet lag prevention

    Science.gov (United States)

    ... medlineplus.gov/ency/patientinstructions/000719.htm Jet lag prevention To use the sharing features on this page, ... Headache Irritability Stomach upset Sore muscles Tips for Prevention Before your trip: Get plenty of rest, eat ...

  2. Jet fire consequence modeling for high-pressure gas pipelines

    Science.gov (United States)

    Coccorullo, Ivano; Russo, Paola

    2016-12-01

    A simple and reliable approach for sizing the hazard area potentially affected by a jet fire as consequence of the failure of high-pressure pipeline is proposed. A release rate model, taking pipeline operation properties and source release properties into account, is coupled with SLAB dispersion model and point source radiation model to calculate the hazard distance. The hazard distance is set beyond the distance at which a low chance of fatality can occur to people exposed and a wooden structure is not expected to burn due to radiation heat of jet fire. The comparison between three gases with different physico-chemical properties (i.e. natural gas, hydrogen, ethylene) is shown. The influence of pipeline operating parameters, such as: pressure, pipeline diameter and length, hole size, on the hazard area for the three gases is evaluated. Finally, a simple correlation is proposed for calculating the hazard distance as function of these parameters.

  3. Jet Engine Noise Reduction

    Science.gov (United States)

    2009-04-01

    Technology Solutions, Lockheed Martin Robert S. Carnes , M.D. NRAC Member, Battelle Memorial Institute MajGen Paul A. Fratarangelo, USMC (Ret) NRAC...Development, Acquisition) (VADM Architzel). The Naval Research Advisory Committee members (Bowes, Bowler, Carnes and Fratarangelo) have broad...Lockheed Martin ADP Boeing: Jet Engine Noise Reduction for Tactical Fighter Aircraft Mr. Tom Kaemming, K. Viswanathan, Ph . D. Tactical Jet Noise

  4. Postharvest response of oranges of ethylene

    Energy Technology Data Exchange (ETDEWEB)

    Aharoni, Y.; Lattar, F.S.; Monselise, S.P.

    1969-01-01

    Since the effect of ethylene on the respiration rate of young unripe oranges has not yet been described, experiments were carried out to study the respiratory response of such fruits to ethylene. Oranges (Citrus sinensis (L.) Osbeck) of the Washington navel, Shamouti and Valencia varieties, growing on a sandy loam near Rehovot, Israel, were picked in June, July, September, December and January. Immediately after picking, they were weighed, placed in glass jars, and stored at 20/sup 0/. Each experiment comprised 12 jars, 4 for each variety. A constant stream (200 ml/min) of air containing 20 ppm of ethylene was run through the jars. The respiration rate was measured by the amount of CO/sub 2/ evolved by the fruits, and based on a fresh weight unit. The results show that in all 3 varieties, ethylene caused an immediate rise in respiration rate, at all stages of development tested, regardless of whether it was applied from the beginning of the test or after a certain period of storage in air. The pattern of response to ethylene of young unripe oranges (picked in June, July, and September) was therefore similar to that of ripe ones (picked in December and January).

  5. Catalytic dehydration of ethanol to ethylene

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Ying; Jin, Zhaosheng; Shen, Wei [SINOPEC Shanghai Research Institute of Petrochemical Technology, Shanghai (China)

    2011-07-01

    The different routes of ethylene production were briefly introduced and the advantage of ethanol to ethylene (ETE) route was explained. Followed by that, the upgraded catalyst applied in this route developed by SINOPEC Shanghai Research Institute of Petrochemical Technology (SRIPT) was introduced together with the development of the ethanol to ethylene process. The core technologies involved in this process development were discussed, such as isothermal fixed-bed reactor, water scrubber and alkaline wash column, two columns of low-temperature separation as well as process heat integration. Furthermore, the performance of one of ethanol industrial plants licensed by SRIPT was reviewed. It is as follows, conversion of ethanol reaches 99% while selectivity of ethylene is over 96% at the reaction temperature of 350{approx}450 C, the liquid hourly space velocity (LHSV)of 0.5{approx}1.0 h{sup -1} and atmosphere pressure. Meanwhile, the catalyst shows its life time of one year. This route is considered not only as an economical and practical process but also as an environmentfriendly path to ethylene production. (orig.)

  6. Jets and QCD

    CERN Document Server

    Ali, Ahmed

    2010-01-01

    The observation of quark and gluon jets has played a crucial role in establishing Quantum Chromodynamics [QCD] as the theory of the strong interactions within the Standard Model of particle physics. The jets, narrowly collimated bundles of hadrons, reflect configurations of quarks and gluons at short distances. Thus, by analysing energy and angular distributions of the jets experimentally, the properties of the basic constituents of matter and the strong forces acting between them can be explored. In this review we summarise the properties of quark and gluon jets and the impact of their observation on Quantum Chromodynamics, primarily the discovery of the gluons as the carriers of the strong force. Focusing on these basic points, jets in $e^+ e^-$ collisions will be in the foreground of the discussion. In addition we will delineate the role of jets as tools for exploring other particle aspects in $ep$ and $pp/p\\bar{p}$ collisions - quark and gluon densities in protons, measurements of the QCD coupling, fundam...

  7. Jet engine. Strahltriebwerk

    Energy Technology Data Exchange (ETDEWEB)

    Weber, F.J.

    1990-11-15

    A gas turbine axial-flow compressor aggregate is mounted in a jet engine consisting of a high-temperature combustion chamber that is composed of conical rings forming slits and set together to a ring column and reaches up to the propelling nozzle, a compressed-air generator supplying the jet engine with compressed air at subsonic speeds and running into the propelling nozzle and a shell encasing the jet engine while leaving a certain intermediate space. The compressor aggregate has a relatively high fuel consumption and high emission rates, involves high production and maintenance costs and puts the blades at a high risk of overheating. The problem basic to the invention was to install a compressed-air generator in the jet engine that has lower fuel consumption and emission rates and is cheaper to manufacture and to service. The invention provides free-piston compressors for compressed-air generators arranged in a circle around the central high-temperature combustion chamber. The ring of compressors can rotate on bearings against the jet engine shell, so that each compressor can be turned to the bottom and serviced there. The jet engine is suitable as an engine for supersonic aircraft.

  8. Jet Mass Spectra in Higgs + One Jet at NNLL

    CERN Document Server

    Jouttenus, Teppo T; Tackmann, Frank J; Waalewijn, Wouter J

    2013-01-01

    The invariant mass of a jet is a benchmark variable describing the structure of jets at the LHC. We calculate the jet mass spectrum for Higgs plus one jet at the LHC at next-to-next-to-leading logarithmic (NNLL) order using a factorization formula. At this order, the cross section becomes sensitive to perturbation theory at the soft m_jet^2/p_T^jet scale. Our calculation is exclusive and uses the 1-jettiness global event shape to implement a veto on additional jets. The dominant dependence on the jet veto is removed by normalizing the spectrum, leaving residual dependence from non-global logarithms depending on the ratio of the jet mass and jet veto variables. For our exclusive jet cross section these non-global logarithms are parametrically smaller than in the inclusive case, allowing us to obtain a complete NNLL result. Results for the dependence of the jet mass spectrum on the kinematics, jet algorithm, and jet size R are given. Using individual partonic channels we illustrate the difference between the je...

  9. THE EFFECT OF ETHYLENE IN MAINTAINING QUALITY OF TOMATO SLICES

    Directory of Open Access Journals (Sweden)

    Darwin H. Pangaribuan

    2009-06-01

    Full Text Available Processes such as slicing tomato fruits disrupt the plant tissue so the products become more perishable compared with the intact fruit. Ethylene production is stimulated during the slicing of fresh cut tomato slices. Experiments were conducted to investigate if ethylene absorbent and exogenous ethylene influences the quality of tomato slices cv. ‘Revolution’ during storage at 5C. In the experiment of ethylene absorbent, experiment was laid out in a completely randomised design. The treatments were plus 10 g and minus ethylene absorbent (KMnO4; Purafil; 5C for 12 d. In the experiment of ethylene concentrations, experiment was laid out in a completely randomised design. The treatments were exogenous ethylene concentrations of 0 (control, 0.1, 1 or 10 L L–1 respectively (5C for 6 h. In both experiments, the treatments were replicated 5 fold. Results showed that ethylene absorbent resulted in reduced ethylene accumulation, and CO2 accumulation in enclosed containers, and firmer slices. Ethylene applied 2 days after slicing stimulated the rate of ethylene production, CO2 production, and produced softer slices during storage. Changes in soluble solids concentration and titratable acidity development were independent of ethylene effects. These experiments showed that ethylene produced by slicing or introduced exogenously had an undesirable effect of accelerating softening of tomato slices.

  10. APC implementation in Chandra Asri - ethylene plant

    Science.gov (United States)

    Sidiq, Mochamad; Mustofa, Ali

    2017-05-01

    Nowadays, the modern process plants are continuously improved for maximizing production, Optimization of the energy and raw material and reducing the risk. Due to many disturbances appearance between the process units, hence, the failure of one unit might have a bad effect on the overall productivity. Ethylene Plant have significant opportunities for using Advanced Process Control (APC) technologies to improve operation stability, push closer to quality or equipment limit, and improve the capability of process units to handle disturbances. APC implementation had considered a best answer for solving multivariable control problem. PT. Chandra Asri Petrochemical, Tbk (CAP) operates a large naphtha cracker complex at Cilegon, Indonesia. To optimize the plant operation and to enhance the benefit, Chandra Asri has been decided to implement Advance Process Control (APC) for ethylene plant. The APC implementation technology scopes at CAP are as follows: 1. Hot Section : Furnaces, Quench Tower 2. Cold Section : Demethanizer, Deethanizer, Acetylene Converter, Ethylene Fractionator, Depropanizer, Propylene Fractionator, Debutanizer

  11. The proton dynamics of ethylene glycol

    CERN Document Server

    Novikov, A G; Sobolev, O V

    2002-01-01

    The results of inelastic neutron scattering experiments on ethylene glycol at T=300 K, T=348 K and T=393 K by using the 'direct-geometry' double time-of-flight neutron-scattering spectrometer DIN-2PI (Frank Laboratory of Neutron Physics, JINR, Dubna) are presented. The quasi-elastic and inelastic components of the neutron scattering have been considered. The diffusion characteristics and generalized frequency distributions for protons of ethylene glycol molecules were obtained from the neutron-scattering spectra. (orig.)

  12. Sinopec Group: Expanding Its Ethylene Business

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    @@ Since its establishment in 1998, Sinopec Group, China's largest integrated energy chemical enterprise, has been sticking to the principle of'developing the petrochemical industry and building core businesses' and actively promoted the development of its ethylene business under the favorable conditions of opportunities and industrial status. In particular in recent years, the group helped China to be the second largest ethylene producing country in the world by the way of importing-learning and absorbing-integrating and innovation through giving more attention to technology innovation, developing its comprehensive advantages, promoting integration between refining and chemical processes.

  13. THE EFFECT OF ETHYLENE IN MAINTAINING QUALITY OF TOMATO SLICES

    OpenAIRE

    Darwin H. Pangaribuan1)

    2009-01-01

    Processes such as slicing tomato fruits disrupt the plant tissue so the products become more perishable compared with the intact fruit. Ethylene production is stimulated during the slicing of fresh cut tomato slices. Experiments were conducted to investigate if ethylene absorbent and exogenous ethylene influences the quality of tomato slices cv. ‘Revolution’ during storage at 5C. In the experiment of ethylene absorbent, experiment was laid out in a completely randomised design. The treat...

  14. Involvement of wound and climacteric ethylene in ripening avocado discs.

    Science.gov (United States)

    Starrett, D A; Laties, G G

    1991-10-01

    Avocado (Persea americana Mill. cv Hass) discs (3 mm thick) ripened in approximately 72 hours when maintained in a flow of moist air and resembled ripe fruit in texture and taste. Ethylene evolution by discs of early and midseason fruit was characterized by two distinct components, viz. wound ethylene, peaking at approximately 18 hours, and climacteric ethylene, rising to a peak at approximately 72 hours. A commensurate respiratory stimulation accompanied each ethylene peak. Aminoethoxyvinyl glycine (AVG) given consecutively, at once and at 24 hours following disc preparation, prevented wound and climacteric respiration peaks, virtually all ethylene production, and ripening. When AVG was administered for the first 24 hours only, respiratory stimulation and softening (ripening) were retarded by at least a day. When AVG was added solely after the first 24 hours, ripening proceeded as in untreated discs, although climacteric ethylene and respiration were diminished. Propylene given together with AVG led to ripening under all circumstances. 2,5-Norbornadiene given continuously stimulated wound ethylene production, and it inhibited climacteric ethylene evolution, the augmentation of ethylene-forming enzyme activity normally associated with climacteric ethylene, and ripening. 2,5-Norbornadiene given at 24 hours fully inhibited ripening. When intact fruit were pulsed with ethylene for 24 hours before discs were prepared therefrom, the respiration rate, ethylene-forming enzyme activity buildup, and rate of ethylene production were all subsequently enhanced. The evidence suggests that ethylene is involved in all phases of disc ripening. In this view, wound ethylene in discs accelerates events that normally take place over an extended period throughout the lag phase in intact fruit, and climacteric ethylene serves the same ripening function in discs and intact fruit alike.

  15. B-jets and z + b-jets at CDF

    Energy Technology Data Exchange (ETDEWEB)

    Jeans, Daniel; /Rome U.

    2006-06-01

    The authors present CDF cross-section measurements for the inclusive production of b jets and the production of b jets in association with a Z{sup 0} boson. Both measurements are in reasonable agreement with NLO QCD predictions.

  16. 40 CFR 180.151 - Ethylene oxide; tolerances for residues.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Ethylene oxide; tolerances for... § 180.151 Ethylene oxide; tolerances for residues. (a) General. (1) Tolerances are established for residues of the antimicrobial agent and insecticide ethylene oxide, when used as a postharvest fumigant in...

  17. 21 CFR 880.6100 - Ethylene oxide gas aerator cabinet.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ethylene oxide gas aerator cabinet. 880.6100... Miscellaneous Devices § 880.6100 Ethylene oxide gas aerator cabinet. (a) Identification. An ethyene oxide gas... required to remove residual ethylene oxide (ETO) from wrapped medical devices that have undergone ETO...

  18. Growth Control by Ethylene: Adjusting Phenotypes to the Environment

    NARCIS (Netherlands)

    Pierik, R.; Sasidharan, R.; Voesenek, L.A.C.J.

    2007-01-01

    Plants phenotypically adjust to environmental challenges, and the gaseous plant hormone ethylene modulates many of these growth adjustments. Ethylene can be involved in environmentally induced growth inhibition as well as growth stimulation. Still, ethylene has long been considered a growth inhibito

  19. 21 CFR 177.1350 - Ethylene-vinyl acetate copolymers.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene-vinyl acetate copolymers. 177.1350 Section... Basic Components of Single and Repeated Use Food Contact Surfaces § 177.1350 Ethylene-vinyl acetate copolymers. Ethylene-vinyl acetate copolymers may be safely used as articles or components of...

  20. Relativistic AGN jets I. The delicate interplay between jet structure, cocoon morphology and jet-head propagation

    NARCIS (Netherlands)

    Walg, S.; Achterberg, A.; Markoff, S.; Keppens, R.; Meliani, Z.

    2013-01-01

    Astrophysical jets reveal strong signs of radial structure. They suggest that the inner region of the jet, the jet spine, consists of a low-density, fast-moving gas, while the outer region of the jet consists of a more dense and slower moving gas, called the jet sheath. Moreover, if jets carry angul

  1. POLYMERIZATION OF ETHYLENE METHYL PHOSPHATE IN THE PRESENCE OF SODIUM POLY(ETHYLENE GLYCOL)ATE

    Institute of Scientific and Technical Information of China (English)

    Jie Wen; Ren-xi Zhuo; Lu Wang

    1999-01-01

    Poly(ethylene methyl phosphate)-poly(ethylene glycol)-poly(ethylene methyl phosphate) triblock copolymers carrying hydroxyl group at both chain ends were synthesized with sodium poly(ethylene glycol)ate as initiator. The effects of the factors such as solvent, amount of the initiator and reaction time were investigated. The copolymers were characterized by IR, 1H-NMR, 1H{31p}-NMR, 13C-NMR, 31P{1H}-NMR, and DSC. High molecular weight of the copolymer and high yield of the polymerization were achieved within 3 min at 25℃. The polymerization process was studied by 31P{1H}-NMR and transesterification was found during longer polymerization time.

  2. Jet Substructure by Accident

    CERN Document Server

    Cohen, Timothy; Lisanti, Mariangela; Lou, Hou Keong

    2012-01-01

    We propose a new search strategy for high-multiplicity hadronic final states. When new particles are produced at threshold, the distribution of their decay products is approximately isotropic. If there are many partons in the final state, it is likely that several will be clustered into the same large-radius jet. The resulting jet exhibits substructure, even though the parent states are not boosted. This "accidental" substructure is a powerful discriminant against background because it is more pronounced for high-multiplicity signals than for QCD multijets. We demonstrate how to take advantage of accidental substructure to reduce backgrounds without relying on the presence of missing energy. As an example, we present the expected limits for several R-parity violating gluino decay topologies. This approach allows for the determination of QCD backgrounds using data-driven methods, which is crucial for the feasibility of any search that targets signatures with many jets and suppressed missing energy.

  3. Renewable jet fuel.

    Science.gov (United States)

    Kallio, Pauli; Pásztor, András; Akhtar, M Kalim; Jones, Patrik R

    2014-04-01

    Novel strategies for sustainable replacement of finite fossil fuels are intensely pursued in fundamental research, applied science and industry. In the case of jet fuels used in gas-turbine engine aircrafts, the production and use of synthetic bio-derived kerosenes are advancing rapidly. Microbial biotechnology could potentially also be used to complement the renewable production of jet fuel, as demonstrated by the production of bioethanol and biodiesel for piston engine vehicles. Engineered microbial biosynthesis of medium chain length alkanes, which constitute the major fraction of petroleum-based jet fuels, was recently demonstrated. Although efficiencies currently are far from that needed for commercial application, this discovery has spurred research towards future production platforms using both fermentative and direct photobiological routes. Copyright © 2013 Elsevier Ltd. All rights reserved.

  4. Multichannel discharge between jet electrolyte cathode and jet electrolyte anode

    NARCIS (Netherlands)

    Shakirova, E. F.; Gaitsin, Al. F.; Son, E. E.

    2011-01-01

    We present the results of an experimental study of multichannel discharge between a jet electrolyte cathode and jet electrolyte anode within a wide range of parameters. We pioneer the reveal of the burning particularities and characteristics of multichannel discharge with jet electrolyte and droplet

  5. Polymerization of ethylene oxide using yttrium isopropoxide

    NARCIS (Netherlands)

    Choi, Young K.; Stevels, W.M.; Ankone, Martinus J.K.; Dijkstra, Pieter J.; Kim, Sung W.; Feijen, Jan

    1996-01-01

    Well defined poly(ethylene oxide)s were prepared using yttrium isopropoxide as an initiator. End group analysis using 1H- and 13C NMR spectroscopy revealed that only polymers with isopropyl ether and hydroxyl end groups were produced. The molecular weight is controlled by the initial amount of

  6. Complete recovery after massive ethylene glycol ingestion.

    Science.gov (United States)

    Curtin, L; Kraner, J; Wine, H; Savitt, D; Abuelo, J G

    1992-06-01

    We treated a 64-year-old man who recovered completely from a massive antifreeze ingestion with ethylene glycol levels well above those of previously described survivors. Rapid and aggressive treatment of the patient with recognized methods, including hemodialysis, resulted in the favorable outcome.

  7. Occurrence of ethylene in anaerobic soil

    Energy Technology Data Exchange (ETDEWEB)

    Smith, K.A.; Restall, S.W.F.

    1971-01-01

    The production of ethylene and other hydrocarbon gases by soils under anaerobic conditions was measured by gas chromatography. Ethylene was the only hydrocarbon gas which occurred in physiologically significant concentrations; more than 20 ppm was found in several soils after 10 days at 20/sup 0/C. These concentrations were considerably higher than those which were known to cause severe reductions in the extension of root axes of some plant species. Experiments with sterilized and unsterilized soil indicated that ethylene was produced by enzyme activity and not by chemical action. The gas was found in soil when the oxygen concentration fell below 2%; total evolution was correlated with organic matter content, and was affected by drying and rewetting and by the growth of plant roots. The rate of production was increased by raising the temperature and by addition of glucose or peptone; high concentrations of nitrate depressed the rate, but sulfate and phosphate had little effect. It is concluded that ethylene may be a significant factor in causing injury to crop plants under waterlogged conditions and also in situations where anaerobic pockets occur within a mainly aerobic soil structure, provided that escape of the gas from the soil is impeded sufficiently to allow inhibitory concentrations to build up in the vicinity of plant roots. 31 references, 7 figures, 3 tables.

  8. Heat Bonding of Irradiated Ethylene Vinyl Acetate

    Science.gov (United States)

    Slack, D. H.

    1986-01-01

    Reliable method now available for joining parts of this difficult-tobond material. Heating fixture encircles ethylene vinyl acetate multiplesocket part, providing heat to it and to tubes inserted in it. Fixtures specially designed to match parts to be bonded. Tube-and-socket bonds made with this technique subjected to tensile tests. Bond strengths of 50 percent that of base material obtained consistently.

  9. Relativistic AGN jets I. The delicate interplay between jet structure, cocoon morphology and jet-head propagation

    Science.gov (United States)

    Walg, S.; Achterberg, A.; Markoff, S.; Keppens, R.; Meliani, Z.

    2013-08-01

    Astrophysical jets reveal strong signs of radial structure. They suggest that the inner region of the jet, the jet spine, consists of a low-density, fast-moving gas, while the outer region of the jet consists of a more dense and slower moving gas, called the jet sheath. Moreover, if jets carry angular momentum, the resultant centrifugal forces lead to a radial stratification. Current observations are not able to fully resolve the radial structure, so little is known about its actual profile. We present three active galactic nuclei jet models in 2.5D of which two have been given a radial structure. The first model is a homogeneous jet, the only model that does not carry angular momentum; the second model is a spine-sheath jet with an isothermal equation of state; and the third jet model is a (piecewise) isochoric spine-sheath jet, with constant but different densities for jet spine and jet sheath. In this paper, we look at the effects of radial stratification on jet integrity, mixing between the different jet components and global morphology of the jet-head and surrounding cocoon. We consider steady jets that have been active for 23 Myr. All jets have developed the same number of strong internal shocks along their jet axis at the final time of simulation. These shocks arise when vortices are being shed by the jet-head. We find that all three jets maintain their stability all the way up to the jet-head. The isothermal jet maintains part of its structural integrity at the jet-head where the distinction between jet spine and jet sheath material can still be made. In this case, mixing between jet spine and jet sheath within the jet is fairly inefficient. The isochoric jet, on the other hand, loses its structural jet integrity fairly quickly after the jet is injected. At its jet-head, little structure is maintained and the central part of the jet predominantly consists of jet sheath material. In this case, jet spine and jet sheath material mix efficiently within the jet

  10. Resolving boosted jets with XCone

    Energy Technology Data Exchange (ETDEWEB)

    Thaler, Jesse; Wilkason, Thomas F. [Center for Theoretical Physics, Massachusetts Institute of Technology,Cambridge, MA, 02139 (United States)

    2015-12-09

    We show how the recently proposed XCone jet algorithm http://dx.doi.org/10.1007/JHEP11(2015)072 smoothly interpolates between resolved and boosted kinematics. When using standard jet algorithms to reconstruct the decays of hadronic resonances like top quarks and Higgs bosons, one typically needs separate analysis strategies to handle the resolved regime of well-separated jets and the boosted regime of fat jets with substructure. XCone, by contrast, is an exclusive cone jet algorithm that always returns a fixed number of jets, so jet regions remain resolved even when (sub)jets are overlapping in the boosted regime. In this paper, we perform three LHC case studies — dijet resonances, Higgs decays to bottom quarks, and all-hadronic top pairs — that demonstrate the physics applications of XCone over a wide kinematic range.

  11. Resolving boosted jets with XCone

    Science.gov (United States)

    Thaler, Jesse; Wilkason, Thomas F.

    2015-12-01

    We show how the recently proposed XCone jet algorithm [1] smoothly interpolates between resolved and boosted kinematics. When using standard jet algorithms to reconstruct the decays of hadronic resonances like top quarks and Higgs bosons, one typically needs separate analysis strategies to handle the resolved regime of well-separated jets and the boosted regime of fat jets with substructure. XCone, by contrast, is an exclusive cone jet algorithm that always returns a fixed number of jets, so jet regions remain resolved even when (sub)jets are overlapping in the boosted regime. In this paper, we perform three LHC case studies — dijet resonances, Higgs decays to bottom quarks, and all-hadronic top pairs — that demonstrate the physics applications of XCone over a wide kinematic range.

  12. Resolving Boosted Jets with XCone

    CERN Document Server

    Thaler, Jesse

    2015-01-01

    We show how the recently proposed XCone jet algorithm smoothly interpolates between resolved and boosted kinematics. When using standard jet algorithms to reconstruct the decays of hadronic resonances like top quarks and Higgs bosons, one typically needs separate analysis strategies to handle the resolved regime of well-separated jets and the boosted regime of fat jets with substructure. XCone, by contrast, is an exclusive cone jet algorithm that always returns a fixed number of jets, so jet regions remain resolved even when (sub)jets are overlapping in the boosted regime. In this paper, we perform three LHC case studies---dijet resonances, Higgs decays to bottom quarks, and all-hadronic top pairs---that demonstrate the physics applications of XCone over a wide kinematic range.

  13. Jet Photoproduction at THERA

    OpenAIRE

    Klasen, M.

    2001-01-01

    We demonstrate that a future high-energy electron-proton collider like THERA could largely extend the current HERA program in jet photoproduction of testing QCD and determining the partonic structure of the proton and the photon. Depending on the electron beam energy (250-500 GeV) and the collider mode ($ep$ or $\\gamma p$), the range in the hard transverse energy scale of the jets could be increased by a factor of 2-3 and the reach in the momentum fraction $x$ of the partons in the proton or ...

  14. Jet Physics in ATLAS

    CERN Document Server

    Sandoval, C; The ATLAS collaboration

    2012-01-01

    Measurements of hadronic jets provide tests of strong interactions which are interesting both in their own right and as backgrounds to many New Physics searches. It is also through tests of Quantum Chromodynamics that new physics may be discovered. The extensive dataset recorded with the ATLAS detector throughout the 7 TeV centre-of-mass LHC operation period allows QCD to be probed at distances never reached before. We present a review of selected ATLAS jet physics measurements. These measurements constitute precision tests of QCD in a new energy regime, and show sensitivity to the parton densities in the proton and to the value of the strong coupling, alpha_s.

  15. OPAL Jet Chamber Prototype

    CERN Multimedia

    OPAL was one of the four experiments installed at the LEP particle accelerator from 1989 - 2000. OPAL's central tracking system consists of (in order of increasing radius) a silicon microvertex detector, a vertex detector, a jet chamber, and z-chambers. All the tracking detectors work by observing the ionization of atoms by charged particles passing by: when the atoms are ionized, electrons are knocked out of their atomic orbitals, and are then able to move freely in the detector. These ionization electrons are detected in the dirfferent parts of the tracking system. This piece is a prototype of the jet chambers

  16. Flame ignition studies of conventional and alternative jet fuels and surrogate components

    Science.gov (United States)

    Liu, Ning

    Practical jet fuels are widely used in air-breathing propulsion, but the chemical mechanisms that control their combustion are not yet understood. Thousands of components are contained in conventional and alternative jet fuels, making thus any effort to model their combustion behavior a daunting task. That has been the motivation behind the development of surrogate fuels that contain typically a small number of neat components, whose physical properties and combustion behavior mimic those of the real jet fuel, and whose kinetics could be modeled with increased degree of confidence. Towards that end, a large number of experimental data are required both for the real fuels and the attendant surrogate components that could be used to develop and validate detailed kinetic models. Those kinetic models could be used then upon reduction to model a combustor and eventually optimize its performance. Among all flame phenomena, ignition is rather sensitive to the oxidative and pyrolytic propensity of the fuel as well as to its diffusivity. The counterflow configuration is ideal in probing both the fuel reactivity and diffusivity aspects of the ignition process and it was used in the present work to determine the ignition temperatures of premixed and non-premixed flames of a variety of fuels relevant to air-breathing propulsion. The experiments were performed at atmospheric pressure, elevated unburned fuel mixture temperatures, and various strain rates that were measured locally. Several recent kinetic models were used in direct numerical simulations of the experiments and the computed results were tested against the experimental data. Furthermore, through sensitivity, reaction path, and structure analyses of the computed flames, insight was provided into the dominant mechanisms that control ignition. It was found that ignition is primarily sensitive to fuel diffusion and secondarily sensitive to chemical kinetics and intermediate species diffusivities under the low fuel

  17. Transcriptional regulation of the ethylene response factor LeERF2 in the expression of ethylene biosynthesis genes controls ethylene production in tomato and tobacco.

    Science.gov (United States)

    Zhang, Zhijin; Zhang, Haiwen; Quan, Ruidan; Wang, Xue-Chen; Huang, Rongfeng

    2009-05-01

    Fine-tuning of ethylene production plays an important role in developmental processes and in plant responses to stress, but very little is known about the regulation of ethylene response factor (ERF) proteins in ethylene biosynthesis genes and ethylene production. Identifying cis-acting elements and transcription factors that play a role in this process, therefore, is important. Previously, a tomato (Solanum lycopersicum [f. sp. Lycopersicon esculentum]) ERF protein, LeERF2, an allele of TERF2, was reported to confer ethylene triple response on plants. This paper reports the transcriptional modulation of LeERF2/TERF2 in ethylene biosynthesis in tomato and tobacco (Nicotiana tabacum). Using overexpressing and antisense LeERF2/TERF2 transgenic tomato, we found that LeERF2/TERF2 is an important regulator in the expression of ethylene biosynthesis genes and the production of ethylene. Expression analysis revealed that LeERF2/TERF2 is ethylene inducible, and ethylene production stimulated by ethylene was suppressed in antisense LeERF2/TERF2 transgenic tomato, indicating LeERF2/TERF2 to be a positive regulator in the feedback loop of ethylene induction. Further research showed that LeERF2/TERF2 conservatively modulates ethylene biosynthesis in tobacco and that such regulation in tobacco is associated with the elongation of the hypocotyl and insensitivity to abscisic acid and glucose during germination and seedling development. The effects on ethylene synthesis were similar to those of another ERF protein, TERF1, because TERF1 and LeERF2/TERF2 have overlapping roles in the transcriptional regulation of ethylene biosynthesis in tobacco. Biochemical analysis showed that LeERF2/TERF2 interacted with GCC box in the promoter of NtACS3 and with dehydration-responsive element in the promoter of LeACO3, resulting in transcriptional activation of the genes for ethylene biosynthesis in tomato and tobacco, which is a novel regulatory function of ERF proteins in plant ethylene

  18. Ethylene Inhibits Cell Proliferation of the Arabidopsis Root Meristem.

    Science.gov (United States)

    Street, Ian H; Aman, Sitwat; Zubo, Yan; Ramzan, Aleena; Wang, Xiaomin; Shakeel, Samina N; Kieber, Joseph J; Schaller, G Eric

    2015-09-01

    The root system of plants plays a critical role in plant growth and survival, with root growth being dependent on both cell proliferation and cell elongation. Multiple phytohormones interact to control root growth, including ethylene, which is primarily known for its role in controlling root cell elongation. We find that ethylene also negatively regulates cell proliferation at the root meristem of Arabidopsis (Arabidopsis thaliana). Genetic analysis indicates that the inhibition of cell proliferation involves two pathways operating downstream of the ethylene receptors. The major pathway is the canonical ethylene signal transduction pathway that incorporates CONSTITUTIVE TRIPLE RESPONSE1, ETHYLENE INSENSITIVE2, and the ETHYLENE INSENSITIVE3 family of transcription factors. The secondary pathway is a phosphorelay based on genetic analysis of receptor histidine kinase activity and mutants involving the type B response regulators. Analysis of ethylene-dependent gene expression and genetic analysis supports SHORT HYPOCOTYL2, a repressor of auxin signaling, as one mediator of the ethylene response and furthermore, indicates that SHORT HYPOCOTYL2 is a point of convergence for both ethylene and cytokinin in negatively regulating cell proliferation. Additional analysis indicates that ethylene signaling contributes but is not required for cytokinin to inhibit activity of the root meristem. These results identify key elements, along with points of cross talk with cytokinin and auxin, by which ethylene negatively regulates cell proliferation at the root apical meristem. © 2015 American Society of Plant Biologists. All Rights Reserved.

  19. Jet substructure using semi-inclusive jet functions within SCET

    CERN Document Server

    Kang, Zhong-Bo; Vitev, Ivan

    2016-01-01

    We propose a new method to evaluate jet substructure observables in inclusive jet measurements based upon semi-inclusive jet functions within the framework of Soft Collinear Effective Theory (SCET). In this work we consider the jet fragmentation function, where a hadron $h$ is identified inside a fully reconstructed jet as a first example. We introduce a new semi-inclusive fragmenting jet function ${\\mathcal G}^h_i(z= \\omega_J/\\omega,z_h=\\omega_h/\\omega_J,\\omega_J, R,\\mu)$ which depends on the jet radius $R$ and the large light-cone momenta of the parton '$i$' initiating the jet ($\\omega$), the jet ($\\omega_J$), and the hadron $h$ ($\\omega_h$). We are then able to express the jet fragmentation function as a semi-inclusive jet observable rather than as an exclusive one, which is closer to the actual experimental measurements. We demonstrate the consistency of the effective field theory treatment and standard perturbative QCD calculations at next-to-leading order (NLO). We further derive the renormalization gro...

  20. Intermonsoonal equatorial jets

    Digital Repository Service at National Institute of Oceanography (India)

    Muraleedharan, P.M.

    Three transects each from the cruises of R V Pioneer (84 , 88 degrees and 92 degrees E) during May-June 1964 and R V Vityaz (77 , 84 degrees and 94 degrees E) during October-November 1962 were used to compare pre and postmonsoon equatorial jets...

  1. Fluid Jet Polishing

    NARCIS (Netherlands)

    Booij, S.M.

    2003-01-01

    The goal of this thesis research was to investigate the possibilities and limitations of the Fluid Jet Polishing (FJP) technique. FJP is a new optical fabrication technique that is capable of making shape corrections and reducing the surface roughness of glass and other materials. The principle of o

  2. Fluid Jet Polishing

    NARCIS (Netherlands)

    Booij, S.M.

    2003-01-01

    The goal of this thesis research was to investigate the possibilities and limitations of the Fluid Jet Polishing (FJP) technique. FJP is a new optical fabrication technique that is capable of making shape corrections and reducing the surface roughness of glass and other materials. The principle of

  3. Jet-Images: Computer Vision Inspired Techniques for Jet Tagging

    CERN Document Server

    Cogan, Josh; Strauss, Emanuel; Schwarztman, Ariel

    2014-01-01

    We introduce a novel approach to jet tagging and classification through the use of techniques inspired by computer vision. Drawing parallels to the problem of facial recognition in images, we define a jet-image using calorimeter towers as the elements of the image and establish jet-image preprocessing methods. For the jet-image processing step, we develop a discriminant for classifying the jet-images derived using Fisher discriminant analysis. The effectiveness of the technique is shown within the context of identifying boosted hadronic W boson decays with respect to a background of quark- and gluon- initiated jets. Using Monte Carlo simulation, we demonstrate that the performance of this technique introduces additional discriminating power over other substructure approaches, and gives significant insight into the internal structure of jets.

  4. Jet-images: computer vision inspired techniques for jet tagging

    Energy Technology Data Exchange (ETDEWEB)

    Cogan, Josh; Kagan, Michael; Strauss, Emanuel; Schwarztman, Ariel [SLAC National Accelerator Laboratory,Menlo Park, CA 94028 (United States)

    2015-02-18

    We introduce a novel approach to jet tagging and classification through the use of techniques inspired by computer vision. Drawing parallels to the problem of facial recognition in images, we define a jet-image using calorimeter towers as the elements of the image and establish jet-image preprocessing methods. For the jet-image processing step, we develop a discriminant for classifying the jet-images derived using Fisher discriminant analysis. The effectiveness of the technique is shown within the context of identifying boosted hadronic W boson decays with respect to a background of quark- and gluon-initiated jets. Using Monte Carlo simulation, we demonstrate that the performance of this technique introduces additional discriminating power over other substructure approaches, and gives significant insight into the internal structure of jets.

  5. Jet substructure using semi-inclusive jet functions in SCET

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Zhong-Bo [Theoretical Division, Los Alamos National Laboratory,Los Alamos, NM 87545 (United States); Department of Physics and Astronomy, University of California,Los Angeles, CA 90095 (United States); Ringer, Felix; Vitev, Ivan [Theoretical Division, Los Alamos National Laboratory,Los Alamos, NM 87545 (United States)

    2016-11-25

    We propose a new method to evaluate jet substructure observables in inclusive jet measurements, based upon semi-inclusive jet functions in the framework of Soft Collinear Effective Theory (SCET). As a first example, we consider the jet fragmentation function, where a hadron h is identified inside a fully reconstructed jet. We introduce a new semi-inclusive fragmenting jet function G{sub i}{sup h}(z=ω{sub J}/ω,z{sub h}=ω{sub h}/ω{sub J},ω{sub J},R,μ), which depends on the jet radius R and the large light-cone momenta of the parton ‘i’ initiating the jet (ω), the jet (ω{sub J}), and the hadron h (ω{sub h}). The jet fragmentation function can then be expressed as a semi-inclusive observable, in the spirit of actual experimental measurements, rather than as an exclusive one. We demonstrate the consistency of the effective field theory treatment and standard perturbative QCD calculations of this observable at next-to-leading order (NLO). The renormalization group (RG) equation for the semi-inclusive fragmenting jet function G{sub i}{sup h}(z,z{sub h},ω{sub J},R,μ) are also derived and shown to follow exactly the usual timelike DGLAP evolution equations for fragmentation functions. The newly obtained RG equations can be used to perform the resummation of single logarithms of the jet radius parameter R up to next-to-leading logarithmic (NLL{sub R}) accuracy. In combination with the fixed NLO calculation, we obtain NLO+NLL{sub R} results for the hadron distribution inside the jet. We present numerical results for pp→(jet h)X in the new framework, and find excellent agreement with existing LHC experimental data.

  6. Relativistic AGN jets II. Jet properties and mixing effects for episodic jet activity

    CERN Document Server

    Walg, Sander; Markoff, Sera; Keppens, Rony; Porth, Oliver

    2013-01-01

    Various radio galaxies show signs of having gone through episodic jet outbursts in the past. An example is the class of double-double radio galaxies (DDRGs). However, to follow the evolution of an individual source in real-time is impossible due to the large time scales involved. Numerical studies provide a powerful tool to investigate the temporal behavior of episodic jet outbursts in a (magneto-)hydrodynamical setting. We simulate the injection of two jets from active galactic nuclei (AGN), separated by a short interruption time. Three different jet models are compared. We find that an AGN jet outburst cycle can be divided into four phases. The most prominent phase occurs when the restarted jet is propagating completely inside the hot and inflated cocoon left behind by the initial jet. In that case, the jet-head advance speed of the restarted jet is significantly higher than the initial jet-head. While the head of the initial jet interacts strongly with the ambient medium, the restarted jet propagates almos...

  7. Real vs. simulated relativistic jets

    CERN Document Server

    Gómez, J L; Agudo, I; Marscher, A P; Jorstad, S G; Aloy, M A

    2005-01-01

    Intensive VLBI monitoring programs of jets in AGN are showing the existence of intricate emission patterns, such as upstream motions or slow moving and quasi-stationary componentes trailing superluminal features. Relativistic hydrodynamic and emission simulations of jets are in very good agreement with these observations, proving as a powerful tool for the understanding of the physical processes taking place in the jets of AGN, microquasars and GRBs. These simulations show that the variability of the jet emission is the result of a complex combination of phase motions, viewing angle selection effects, and non-linear interactions between perturbations and the underlying jet and/or ambient medium. Both observations and simulations suggest that shock-in-jet models may be an overly simplistic idealization when interpreting the emission structure observed in actual jets.

  8. Turbulent jet in confined counterflow

    Indian Academy of Sciences (India)

    M Sivapragasam; M D Deshpande; S Ramamurthy; P White

    2014-06-01

    The mean flowfield of a turbulent jet issuing into a confined, uniform counterflow was investigated computationally. Based on dimensional analysis, the jet penetration length was shown to scale with jet-to-counterflow momentum flux ratio. This scaling and the computational results reproduce the well-known correct limit of linear growth of the jet penetration length for the unconfined case when the momentum flux ratio is small. However, for the high momentum flux ratio case corresponding to the confinement, the jet penetration length is shown to reach an asymptotic limit of about 3.57 times the confining duct diameter. This conclusion is contrary to the existing results which predict indefinite growth. A simple modification of an existing similarity solution for the jet in an unconfined counterflow provides a convenient framework for presenting the results of the flowfield and jet penetration length.

  9. Pileup subtraction for jet shapes.

    Science.gov (United States)

    Soyez, Gregory; Salam, Gavin P; Kim, Ji-Hun; Dutta, Souvik; Cacciari, Matteo

    2013-04-19

    Jets in high energy hadronic collisions often contain the fingerprints of the particles that produced them. Those fingerprints, and thus the nature of the particles that produced the jets, can be read off with the help of quantities known as jet shapes. Jet shapes are, however, severely affected by pileup, the accumulation in the detector of the residues of the many simultaneous collisions taking place in the Large Hadron Collider (LHC). We introduce a method to correct for pileup effects in jet shapes. Relative to earlier, limited approaches, the key advance resides in its full generality, achieved through a numerical determination, for each jet, of a given shape's susceptibility to pileup. The method rescues the possibility of using jet shapes in the high pileup environment of current and future LHC running, as we show with examples of quark-gluon discrimination and top tagging.

  10. Enzymatic hydrolysis of poly(ethylene furanoate).

    Science.gov (United States)

    Pellis, Alessandro; Haernvall, Karolina; Pichler, Christian M; Ghazaryan, Gagik; Breinbauer, Rolf; Guebitz, Georg M

    2016-10-10

    The urgency of producing new environmentally-friendly polyesters strongly enhanced the development of bio-based poly(ethylene furanoate) (PEF) as an alternative to plastics like poly(ethylene terephthalate) (PET) for applications that include food packaging, personal and home care containers and thermoforming equipment. In this study, PEF powders of various molecular weights (6, 10 and 40kDa) were synthetized and their susceptibility to enzymatic hydrolysis was investigated for the first time. According to LC/TOF-MS analysis, cutinase 1 from Thermobifida cellulosilytica liberated both 2,5-furandicarboxylic acid and oligomers of up to DP4. The enzyme preferentially hydrolyzed PEF with higher molecular weights but was active on all tested substrates. Mild enzymatic hydrolysis of PEF has a potential both for surface functionalization and monomers recycling. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Expected performance of ATLAS for measurements of jets, b-jets, tau-jets, and ETmis

    CERN Document Server

    Sapinski, M

    2002-01-01

    Jets and missing energy are among the most important objects of LHC physics. The accuracy of measurements of missing energy and direction and energy of jets put strong requirements on the detector performance. These requirements and the ATLAS Calorimeter system which is projected to fulfill these requirements are presented. The jet reconstruction algorithms and jet energy scale calibration are shortly discussed. Forward jet tagging, b-tagging and tau-tagging are important issues of many physical analyses. Reconstruction of resonances is an example of complex use of calorimeter performance

  12. Description of the ATLAS jet veto measurement and jet gap jet events at hadronic colliders

    CERN Document Server

    Royon, C

    2014-01-01

    We present a new QCD description of the ATLAS jet veto measurement, using the Banfi- Marchesini-Smye equation to constrain the inter-jet QCD radiation. This equation resums emis- sions of soft gluons at large angles and leads to a very good description of data. We also investigate jet gap jet events in hadron-hadron collisions, in which two jets are produced and separated by a large rapidity gap. Using a renormalisation-group improved NLL kernel implemented in the HERWIG Monte Carlo program, we show that the BFKL predictions are in good agreement with the Tevatron data, and present predictions that could be tested at the LHC.

  13. Traction Drive Inverter Cooling with Submerged Liquid Jet Impingement on Microfinned Enhanced Surfaces (Presentation)

    Energy Technology Data Exchange (ETDEWEB)

    Waye, S.; Narumanchi, S.; Moreno, G.

    2014-09-01

    Jet impingement is one means to improve thermal management for power electronics in electric-drive traction vehicles. Jet impingement on microfin-enhanced surfaces further augments heat transfer and thermal performance. A channel flow heat exchanger from a commercial inverter was characterized as a baseline system for comparison with two new prototype designs using liquid jet impingement on plain and microfinned enhanced surfaces. The submerged jets can target areas with the highest heat flux to provide local cooling, such as areas under insulated-gate bipolar transistors and diode devices. Low power experiments, where four diodes were powered, dissipated 105 W of heat and were used to validate computational fluid dynamics modeling of the baseline and prototype designs. Experiments and modeling used typical automotive flow rates using water-ethylene glycol as a coolant (50%-50% by volume). The computational fluid dynamics model was used to predict full inverter power heat dissipation. The channel flow and jet impingement configurations were tested at full inverter power of 40 to 100 kW (output power) on a dynamometer, translating to an approximate heat dissipation of 1 to 2 kW. With jet impingement, the cold plate material is not critical for the thermal pathway. A high-temperature plastic was used that could eventually be injection molded or formed, with the jets formed from a basic aluminum plate with orifices acting as nozzles. Long-term reliability of the jet nozzles and impingement on enhanced surfaces was examined. For jet impingement on microfinned surfaces, thermal performance increased 17%. Along with a weight reduction of approximately 3 kg, the specific power (kW/kg) increased by 36%, with an increase in power density (kW/L) of 12% compared with the baseline channel flow configuration.

  14. Ethylene Oxide Gas Sterilization of Medical Devices.

    Science.gov (United States)

    Shintani, Hideharu

    2017-01-01

     Ethylene oxide gas is an agent in the sterilization of medical devices due to its effectiveness and compatibility with most materials. The advantages and disadvantages, as well as its recommended uses, are explored in this review article. The variables and their relevance on process optimization are described, the types of processing cycles are detailed and emphasis is given to the design and validation of the sterilization process.

  15. Fragrance material review on ethylene brassylate.

    Science.gov (United States)

    McGinty, D; Letizia, C S; Api, A M

    2011-12-01

    A toxicologic and dermatologic review of ethylene brassylate when used as a fragrance ingredient is presented. Ethylene brassylate is a member of the fragrance structural group macrocyclic lactone and lactide derivatives. The fragrance ingredient described herein is one of 12 structurally diverse C14, C15, and C16 compounds that include (7) saturated mono-and (2) saturated di-ester lactones and (3) unsaturated lactones. For the latter, the double bond is not adjacent to (in conjugation with) the ester group. This review contains a detailed summary of all available toxicology and dermatology papers that are related to ethylene brassylate and is not intended as a stand-alone document. Available data were evaluated, then summarized, and includes: physical properties; acute toxicity; skin irritation; skin sensitization; elicitation; phototoxicity; repeated dose; and genotoxicity data. A safety assessment of the entire macrocyclic lactone and lactide derivatives will be published simultaneously with this document. Please refer to Belsito et al. (2011) for an overall assessment of the safe use of this material and all macrocyclic lactone and lactide derivatives in fragrances. Belsito, D., Bickers, D., Bruze, M., Calow, P., Dagli, M., Fryer, A.D., Greim, H., Hanifin, J.H., Miyachi, Y., Saurat, J.H., Sipes, I.G., 2011. A toxicologic and dermatologic assessment of macrocylic lactone and lactide derivatives when used as fragrance ingredients. Copyright © 2011. Published by Elsevier Ltd.

  16. Fragrance material review on ethylene dodecanedioate.

    Science.gov (United States)

    McGinty, D; Letizia, C S; Api, A M

    2011-12-01

    A toxicologic and dermatologic review of ethylene dodecanedioate when used as a fragrance ingredient is presented. Ethylene dodecanedioate is a member of the fragrance structural group macrocyclic lactone and lactide derivatives. The fragrance ingredient described herein is one of 12 structurally diverse C14, C15, and C16 compounds that include (7) saturated mono- and (2) saturated di-ester lactones and (3) unsaturated lactones. For the latter, the double bond is not adjacent to (in conjugation with) the ester group. This review contains a detailed summary of all available toxicology and dermatology papers that are related to ethylene dodecanedioate and is not intended as a stand-alone document. Available data were evaluated, then summarized, and includes: physical properties; acute toxicity; skin irritation; mucous membrane (eye) irritation; skin sensitization; phototoxicity; repeated dose; and genotoxicity data. A safety assessment of the entire macrocyclic lactone and lactide derivatives will be published simultaneously with this document. Please refer to Belsito et al. (2011) for an overall assessment of the safe use of this material and all macrocyclic lactone and lactide derivatives in fragrances. Belsito, D., Bickers, D., Bruze, M., Calow, P., Dagli, M., Fryer, A.D., Greim, H., Hanifin, J.H., Miyachi, Y., Saurat, J.H., Sipes, I.G., 2011. A toxicologic and dermatologic assessment of macrocylic lactone and lactide derivatives when used as fragrance ingredients. Copyright © 2011. Published by Elsevier Ltd.

  17. ROLE OF ETHYLENE IN RESPONSES OF PLANTS TO NITROGEN AVAILABILITY

    Directory of Open Access Journals (Sweden)

    M Iqbal R Khan

    2015-10-01

    Full Text Available Ethylene is a plant hormone involved in several physiological processes and regulates the plant development during the whole life. Stressful conditions usually activate ethylene biosynthesis and signalling in plants. The availability of nutrients, shortage or excess, influences plant metabolism and ethylene plays an important role in plant adaptation under suboptimal conditions. Among the plant nutrients, the nitrogen (N is one the most important mineral element required for plant growth and development. The availability of N significantly influences plant metabolism, including ethylene biology. The interaction between ethylene and N affects several physiological process such as leaf gas exchanges, roots architecture, leaf, fruits and flowers development. Low plant N use efficiency leads to N loss and N deprivation, which affect ethylene biosynthesis and tissues sensitivity, inducing cell damage and ultimately lysis. Plants may respond differently to N availability balancing ethylene production through its signalling network. This review discusses the recent advances in the interaction between N availability and ethylene at whole plant and different organ levels, and explores how N availability induces ethylene biology and plant responses. Exogenously applied ethylene seems to cope the stress conditions and improves plant physiological performance. This can be explained considering the expression of ethylene biosynthesis and signalling genes under different N availability. A greater understanding of the regulation of N by means of ethylene modulation may help to increase N use efficiency and directly influence crop productivity under conditions of limited N availability, leading to positive effects on the environment. Moreover, efforts should be focused on the effect of N deficiency or excess in fruit trees, where ethylene can have detrimental effects especially during postharvest.

  18. SparkJet Efficiency

    Science.gov (United States)

    Golbabaei-Asl, Mona; Knight, Doyle; Anderson, Kellie; Wilkinson, Stephen

    2013-01-01

    A novel method for determining the thermal efficiency of the SparkJet is proposed. A SparkJet is attached to the end of a pendulum. The motion of the pendulum subsequent to a single spark discharge is measured using a laser displacement sensor. The measured displacement vs time is compared with the predictions of a theoretical perfect gas model to estimate the fraction of the spark discharge energy which results in heating the gas (i.e., increasing the translational-rotational temperature). The results from multiple runs for different capacitances of c = 3, 5, 10, 20, and 40 micro-F show that the thermal efficiency decreases with higher capacitive discharges.

  19. Jet Physics in ATLAS

    CERN Document Server

    Sandoval, C; The ATLAS collaboration

    2012-01-01

    Measurements of hadronic jets provide tests of strong interactions which are interesting both in their own right and as backgrounds to many New Physics searches. It is also through tests of Quantum Chromodynamics that new physics may be discovered. The extensive dataset recorded with the ATLAS detector throughout the 7 TeV and 8 TeV centre-of-mass LHC operation periods allows QCD to be probed at distances never reached before. We present a review of selected ATLAS jet physics measurements. These measurements constitute precision tests of QCD in a new energy regime, and show sensitivity to the parton densities in the proton and to the value of the strong coupling, alpha_s.

  20. Astrophysical Jets and Outflows

    CERN Document Server

    De Gouveia dal Pino, E M

    2004-01-01

    Highly collimated supersonic jets and less collimated outflows are observed to emerge from a wide variety of astrophysical objects. They are seen in young stellar objects (YSOs), proto-planetary nebulae, compact objects (like galactic black holes or microquasars, and X-ray binary stars), and in the nuclei of active galaxies (AGNs). Despite their different physical scales (in size, velocity, and amount of energy transported), they have strong morphological similarities. What physics do they share? These systems either hydrodynamic or magnetohydrodynamic (MHD) in nature and are, as such, governed by non-linear equations. While theoretical models helped us to understand the basic physics of these objects, numerical simulations have been allowing us to go beyond the one-dimensional, steady-state approach extracting vital information. In this lecture, the formation, structure, and evolution of the jets are reviewed with the help of observational information, MHD and purely hydrodynamical modeling, and numerical si...

  1. Interacting Jets from Binary Protostars

    CERN Document Server

    Murphy, G C; O'Sullivan, S; Spicer, D; Bacciotti, F; Rosén, A

    2007-01-01

    We investigate potential models that could explain why multiple proto-stellar systems predominantly show single jets. During their formation, stars most frequently produce energetic outflows and jets. However, binary jets have only been observed in a very small number of systems. We model numerically 3D binary jets for various outflow parameters. We also model the propagation of jets from a specific source, namely L1551 IRS 5, known to have two jets, using recent observations as constraints for simulations with a new MHD code. We examine their morphology and dynamics, and produce synthetic emission maps. We find that the two jets interfere up to the stage where one of them is almost destroyed or engulfed into the second one. We are able to reproduce some of the observational features of L1551 such as the bending of the secondary jet. While the effects of orbital motion are negligible over the jets dynamical timeline, their interaction has significant impact on their morphology. If the jets are not strictly pa...

  2. Jet-Environment Interactions as Diagnostics of Jet Physics

    Science.gov (United States)

    Heinz, Sebastian

    2014-09-01

    In this chapter, we will explore the interaction of jets with their environments. Jets can transport a sizable fraction of accretion energy away from black holes and neutron stars. Because they are collimated, they can travel to distances far beyond the gravitational sphere of influence of the black hole. Yet, their interaction with the interstellar and intergalactic medium must eventually halt their advance and dissipate the energy they carry. The termination of the jet, and the inflation of large scale cavities of relativistic plasma offers one of the most powerful ways to constrain the physics of jets. In this chapter, we will review the inflation of radio lobes, the propagation of hot spots, the creation of shells and cavities, and the bending of jet by proper motion through their environment, both in the context of AGN jets and microquasars.

  3. Micromachined chemical jet dispenser

    Energy Technology Data Exchange (ETDEWEB)

    Swierkowski, S.; Ciarlo, D.

    1996-05-13

    Goal is to develop a multi-channel micromachined chemical fluid jet dispenser that is applicable to prototype tests with biological samples that demonstrate its utility for molecular biology experiments. Objective is to demonstrate a new device capable of ultrasonically ejecting droplets from 10-200 {mu}m diameter capillaries that are arranged in an array that is linear or focused. The device is based on several common fabrication procedures used in MEMS (micro electro mechanical systems) technology: piezoelectric actuators, silicon, etc.

  4. Stationary Relativistic Jets

    CERN Document Server

    Komissarov, S S; Lyutikov, M

    2015-01-01

    In this paper we describe a simple numerical approach which allows to study the structure of steady-state axisymmetric relativistic jets using one-dimensional time-dependent simulations. It is based on the fact that for narrow jets with v~c the steady-state equations of relativistic magnetohydrodynamics can be accurately approximated by the one-dimensional time-dependent equations after the substitution z=ct. Since only the time-dependent codes are now publicly available this is a valuable and efficient alternative to the development of a high-specialized code for the time-independent equations. The approach is also much cheaper and more robust compared to the relaxation method. We tested this technique against numerical and analytical solutions found in literature as well as solutions we obtained using the relaxation method and found it sufficiently accurate. In the process, we discovered the reason for the failure of the self-similar analytical model of the jet reconfinement in relatively flat atmospheres a...

  5. Astrophysical jets and outflows

    Science.gov (United States)

    de Gouveia Dal Pino, Elisabete M.

    Highly collimated supersonic jets and less collimated outflows are observed to emerge from a wide variety of astrophysical objects. They are seen in young stellar objects (YSOs), proto-planetary nebulae, compact objects (like galactic black holes or microquasars, and X-ray binary stars), and in the nuclei of active galaxies (AGNs). Despite their different physical scales (in size, velocity, and amount of energy transported), they have strong morphological similarities. What physics do they share? These systems are either hydrodynamic or magnetohydrodynamic (MHD) in nature and are, as such, governed by non-linear equations. While theoretical models helped us to understand the basic physics of these objects, numerical simulations have been allowing us to go beyond the one-dimensional, steady-state approach extracting vital information. In this lecture, the formation, structure, and evolution of the jets are reviewed with the help of observational information, MHD and purely hydrodynamical modeling, and numerical simulations. Possible applications of the models particularly to YSOs and AGN jets are addressed.

  6. Rapid Confined Mixing Using Transverse Jets Part 2: Multiple Jets

    Science.gov (United States)

    Forliti, David; Salazar, David

    2012-11-01

    An experimental study has been conducted at the Air Force Research Laboratory at Edwards Air Force Base to investigate the properties of confined mixing devices that employ transverse jets. The experiment considers the mixing of water with a mixture of water and fluorescein, and planar laser induced fluorescence was used to measure instantaneous mixture fraction distributions in the cross section view. Part one of this study presents the scaling law development and results for a single confined transverse jet. Part two will describe the results of configurations including multiple transverse jets. The different regimes of mixing behavior, ranging from under to overpenetration of the transverse jets, are characterized in terms of a new scaling law parameter presented in part one. The level of unmixedness, a primary metric for mixing device performance, is quantified for different jet diameters, number of jets, and relative flow rates. It is apparent that the addition of a second transverse jet provides enhanced scalar uniformity in the main pipe flow cross section compared to a single jet. Three and six jet configurations also provide highly uniform scalar distributions. Turbulent scalar fluctuation intensities, spectral features, and spatial eigenfunctions using the proper orthogonal decomposition will be presented. Distribution A: Public Release, Public Affairs Clearance Number: 12656.

  7. Nitric oxide counters ethylene effects on ripening fruits.

    Science.gov (United States)

    Manjunatha, Girigowda; Gupta, Kapuganti J; Lokesh, Veeresh; Mur, Luis A J; Neelwarne, Bhagyalakshmi

    2012-04-01

    Ethylene plays a key role in promoting fruit ripening, so altering its biosynthesis/signaling could be an important means to delay this process. Nitric oxide (NO)-generated signals are now being shown to regulate ethylene pathways. NO signals have been shown to transcriptionally repress the expression of genes involved in ethylene biosynthesis enzymes and post-translationally modify methionine adenosyl transferase (MAT) activity through S-nitrosylation to reduce the availably of methyl groups required to produce ethylene. Additionally, NO cross-talks with plant hormones and other signal molecules and act to orchestrate the suppression of ethylene effects by modulating enzymes/proteins that are generally triggered by ethylene signaling at post-climacteric stage. Thus, medication of endogenous NO production is suggested as a strategy to postpone the climacteric stage of many tropical fruits.

  8. Experimental Study of Ethylene Combustion in a Scramjet Combustor

    Institute of Scientific and Technical Information of China (English)

    XIAO Yin-li; SONG Wen-yan; LE Jia-ling

    2008-01-01

    In this paper the ignition characteristics of gaseous ethylene hydrocarbon fuel is investigated in the supersonic clean airstreams experimental facility with a resistance heater. The generic cavity flame holder is used to create recirculation and promote the fuel/air mixing at the lower wall of the combustor. Three different injection concepts are considered in this research: (1) ethylene injection upstream of the cavity; (2) ethylene and hydrogen injection upstream of the cavity simultaneously; (3) ethylene injection preceded by pilot hydrogen injection. The pilot injection showed to be a supportive tool for holding the flame of the main normal ethylene fuel injection. Therefore, using pilot hydrogen injection and cavity configuration necessitates optimizing the combustor length to ensure the complete combustion and the full liberation of the chemical energy stored in the fuel before exiting the combustor. The present study proved the possibility of igniting the ethylene and maintaining its flame in the supersonic airstreams.

  9. Wall jets created by single and twin high pressure jet impingement

    Science.gov (United States)

    Miller, P.; Wilson, M.

    1993-03-01

    An extensive experimental investigation into the nature of the wall jets produced by single and twin normal jet impingement has been undertaken. Wall jet velocity profiles have been recorded up to 70 jet diameters from the impingement point, at pressures representative of current VStol technology. The tests used fixed convergent nozzles, with nozzle height and spacing and jet pressure being varied. Single jet impingement displays a consistent effect of nozzle height on wall jet development. For twin jet cases a powerful reinforcement exists along the wall jet interaction plane. Remote from the interaction plane the wall jets are weaker than those produced by a single jet impingement.

  10. Decelerating relativistc two-component jets

    NARCIS (Netherlands)

    Meliani, Z.; Keppens, R.

    2009-01-01

    Transverse stratification is a common intrinsic feature of astrophysical jets. There is growing evidence that jets in radio galaxies consist of a fast low-density outflow at the jet axis, surrounded by a slower, denser, extended jet. The inner and outer jet components then have a different origin

  11. Decelerating relativistic two-component jets

    NARCIS (Netherlands)

    Meliani, Z.; Keppens, R.

    2009-01-01

    Transverse stratification is a common intrinsic feature of astrophysical jets. There is growing evidence that jets in radio galaxies consist of a fast low-density outflow at the jet axis, surrounded by a slower, denser, extended jet. The inner and outer jet components then have a different origin

  12. Decelerating relativistic two-component jets

    NARCIS (Netherlands)

    Meliani, Z.; Keppens, R.

    2009-01-01

    Transverse stratification is a common intrinsic feature of astrophysical jets. There is growing evidence that jets in radio galaxies consist of a fast low-density outflow at the jet axis, surrounded by a slower, denser, extended jet. The inner and outer jet components then have a different origin an

  13. Decelerating relativistc two-component jets

    NARCIS (Netherlands)

    Meliani, Z.; Keppens, R.

    2009-01-01

    Transverse stratification is a common intrinsic feature of astrophysical jets. There is growing evidence that jets in radio galaxies consist of a fast low-density outflow at the jet axis, surrounded by a slower, denser, extended jet. The inner and outer jet components then have a different origin an

  14. Control of a Circular Jet

    CERN Document Server

    Gohil, Trushar B; Muralidhar, K

    2010-01-01

    The present study report direct numerical simulation (DNS) of a circular jet and the effect of a large scale perturbation at the jet inlet. The perturbation is used to control the jet for increased spreading. Dual-mode perturbation is obtained by combining an axisymmetric excitation with the helical. In the fluid dynamics videos, an active control of the circular jet at a Reynolds number of 2000 for various frequency ratios (both integer and non-integer) has been demonstrated. When the frequency ratio is fixed to 2, bifurcation of the jet on a plane is evident. However, for a non-integer frequency ratio, the axisymmetric jet is seen to bloom in all directions.

  15. Molecular interactions between ethylene and gibberellic acid pathways in plants

    OpenAIRE

    Rzewuski, Guillaume

    2004-01-01

    Flooding avoidance in deepwater rice is characterised by rapid growth of the youngest internode which allows the plant to keep part of its foliage above the surface of raising flood waters. The primary signal triggering internodal elongation is the phytohormone ethylene which accumulates as a result of increased ethylene biosynthesis and entrapment. Through unknown signalling components, ethylene increases the level of bioactive gibberellins (GA) and responsiveness of the tissue to GA. GA is ...

  16. Sorption interactions between ethylene glycol and carbon nanotubes

    Science.gov (United States)

    Butyrskaya, E. V.; Belyakova, N. V.; Nechaeva, L. S.; Shaposhnik, V. A.; Selemenev, V. F.

    2017-03-01

    The adsorption of ethylene glycol by carbon nanoparticles is studied. Carbon nanoparticles with the highest affinity to ethylene glycol are identified, and an adsorption isotherm is constructed. Based on quantum chemical calculations of the energies of interaction between the sorbate and nanotubes with (4,4) and (6,6) chirality, a change in mechanism is revealed upon the monomolecular adsorption of ethylene glycol on carbon nanotubes, and the adsorption isotherm is thus interpreted.

  17. Ethylene production with engineered Synechocystis sp PCC 6803 strains.

    Science.gov (United States)

    Veetil, Vinod Puthan; Angermayr, S Andreas; Hellingwerf, Klaas J

    2017-02-23

    Metabolic engineering and synthetic biology of cyanobacteria offer a promising sustainable alternative approach for fossil-based ethylene production, by using sunlight via oxygenic photosynthesis, to convert carbon dioxide directly into ethylene. Towards this, both well-studied cyanobacteria, i.e., Synechocystis sp PCC 6803 and Synechococcus elongatus PCC 7942, have been engineered to produce ethylene by introducing the ethylene-forming enzyme (Efe) from Pseudomonas syringae pv. phaseolicola PK2 (the Kudzu strain), which catalyzes the conversion of the ubiquitous tricarboxylic acid cycle intermediate 2-oxoglutarate into ethylene. This study focuses on Synechocystis sp PCC 6803 and shows stable ethylene production through the integration of a codon-optimized version of the efe gene under control of the Ptrc promoter and the core Shine-Dalgarno sequence (5'-AGGAGG-3') as the ribosome-binding site (RBS), at the slr0168 neutral site. We have increased ethylene production twofold by RBS screening and further investigated improving ethylene production from a single gene copy of efe, using multiple tandem promoters and by putting our best construct on an RSF1010-based broad-host-self-replicating plasmid, which has a higher copy number than the genome. Moreover, to raise the intracellular amounts of the key Efe substrate, 2-oxoglutarate, from which ethylene is formed, we constructed a glycogen-synthesis knockout mutant (ΔglgC) and introduced the ethylene biosynthetic pathway in it. Under nitrogen limiting conditions, the glycogen knockout strain has increased intracellular 2-oxoglutarate levels; however, surprisingly, ethylene production was lower in this strain than in the wild-type background. Making use of different RBS sequences, production of ethylene ranging over a 20-fold difference has been achieved. However, a further increase of production through multiple tandem promoters and a broad-host plasmid was not achieved speculating that the transcription strength and

  18. Defining sale ethylene for long term storage of tulip bulbs

    OpenAIRE

    Wild, de, H.P.J.; Peppelenbos, H.W.; Dijkstra, M.H.G.E.; Gude, H.

    2002-01-01

    The maximum ethylene level that can be permitted in storage rooms, without causing damage to tulip bulbs, is not exactly known. Therefore, a zero-tolerance for the presence of ethylene during storage of tulip bulbs is common practice. This results in excessive ventilation and coherent large energy costs. It is questioned whether this is always necessary. In different phases of the storage period the critical levels of ethylene were determined. Bulbs of eight economically important cultivars (...

  19. Impeller for Water Jet Propulsion

    Science.gov (United States)

    2004-01-01

    Marshall Space Flight Center engineers helped North American Marine Jet (NAMJ), Inc. improve the proposed design of a new impeller for jet propulsion system. With a three-dimensional computer model of the new marine jet engine blades, engineers were able to quickly create a solid ploycarbonate model of it. The rapid prototyping allowed the company to avoid many time-consuming and costly steps in creating the impeller.

  20. Material Transport with Air Jet

    Directory of Open Access Journals (Sweden)

    István Patkó

    2005-11-01

    Full Text Available In the field of industry, there are only a very few examples of material transportwith air jet, and one of these is the air jet loom. In this weaving technology, the weft (thetransversal yarn of the fabric is shot by air jet. This paper will set up the mathematicalmodel of yarn end movement. For a special case, I will specify a solution of the model.

  1. Genetic Basis of Ethylene Perception and Signal Transduction in Arabidopsis

    Institute of Scientific and Technical Information of China (English)

    Ziqiang Zhu; Hongwei Guo

    2008-01-01

    Ethylene is a simple gaseous hormone in plants. It plays important roles in plant development and stress tolerance. In the presence of ethylene treatment, all ethylene receptors are in an activated form, which can physically interact with CTR1 and consequently recruit CTR1 protein to endoplasmic reticulum membrane to activate it. Activated CTR1 suppresses the downstream signal transduction by an unknown mechanism. Upon binding to its receptors, ethylene will inactivate the receptor/CTR1 module and in turn alleviate their inhibitory effect on two positive regulators acting downstream of CTRI: EIN2 and EIN3. Genetic study reveals that EIN2 is an essential component in the ethylene signaling pathway but its biochemical function remains a mystery. EIN3 is a plant-specific transcription factor and its protein abundance in the nucleus is rapidly induced upon ethylene treatment. In the absence of ethylene signal, EIN3 protein is degraded by an SCF complex containing one of the two F-box proteins EBF1/EBF2 in a 26S proteasome-dependent manner. EIN3 can bind to the promoter sequences of a number of downstream components, such as ERFs, which in turn bind to a GCC box,a cis-element found in many ethylene-regulated defense genes. Ethylene has been shown to also regulate many other hormones' signaling pathways including auxin, abscisic acid and jasmonic acid, implying the existence of complicated signaling networks in the growth, development and defense responses of various plants.

  2. Chemical Genetic Dissection of Brassinosteroid-Ethylene Interaction

    Institute of Scientific and Technical Information of China (English)

    Joshua M.Gendron; Asif Haque; Nathan Gendron; Timothy Chang; Tadao Asami; Zhi-Yong Wang

    2008-01-01

    We undertook a chemical genetics screen to identify chemical inhibitors of brassinosteroid (BR) action.From a chemical library of 10,000 small molecules,one compound was found to inhibit hypocotyl length and activate the expression of a BR-repressed reporter gene (CPD::GUS) in Arabidopsis,and it was named brassinopride (BRP).These effects of BRP could be reversed by co-treatment with brassinolide,suggesting that BRP either directly or indirectly inhibits BR biosynthesis.Interestingly,the compound causes exaggerated apical hooks,similar to that caused by ethylene treatment.The BRP-induced apical hook phenotype can be blocked by a chemical inhibitor of ethylene perception or an ethylene-insensitive mutant,suggesting that,in addition to inhibiting BR,BRP activates ethylene response.Analysis of BRP analogs provided clues about structural features important for its effects on two separate targets in the BR and ethylene pathways.Analyses of the responses of various BR and ethylene mutants to BRP,ethylene,and BR treatments revealed modes of cross-talk between ethylene and BR in dark-grown seedlings.Our results suggest that active downstream BR signaling,but not BR synthesis or a BR gradient,is required for ethylene-induced apical hook formation.The BRP-related compounds can be useful tools for manipulating plant growth and studying hormone interactions.

  3. Ethylene regulates the susceptible response to pathogen infection in tomato.

    Science.gov (United States)

    Lund, S T; Stall, R E; Klee, H J

    1998-03-01

    Ethylene evolution occurs concomitantly with the progression of disease symptoms in response to many virulent pathogen infections in plants. A tomato mutant impaired in ethylene perception-Never ripe-exhibited a significant reduction in disease symptoms in comparison to the wild type after inoculations of both genotypes with virulent bacterial (Xanthomonas campestris pv vesicatoria and Pseudomonas syringae pv tomato) and fungal (Fusarium oxysporum f sp lycopersici) pathogens. Bacterial spot disease symptoms were also reduced in tomato genotypes impaired in ethylene synthesis (1-aminocyclopropane-1-carboxylic acid deaminase) and perception (14893), thereby corroborating a reducing effect for ethylene insensitivity on foliar disease development. The reduction in foliar disease symptoms in Never ripe plants was a specific effect of ethylene insensitivity and was not due to reductions in bacterial populations or decreased ethylene synthesis. PR-1B1 mRNA accumulation in response to X. c. vesicatoria infection was not affected by ethylene insensitivity, indicating that ethylene is not required for defense gene induction. Our findings suggest that broad tolerance of diverse vegetative diseases may be achieved via engineering of ethylene insensitivity in tomato.

  4. Gravitropism in higher plant shoots. I - A role for ethylene

    Science.gov (United States)

    Wheeler, Raymond M.; Salisbury, Frank B.

    1981-01-01

    Two inhibitors of ethylene synthesis, Co(2+) and aminoethoxyvinylglycine (AVG), and two inhibitors of ethylene action, Ag(+) and CO2, are shown to delay the gravitropic response of cocklebur (Xanthium strumarium L.), tomato (Lycopersicon esculentum Mill.), and castor bean (Ricinus communis L.) stems. Gentle shaking on a mechanical shaker does not inhibit the gravitropic response, but vigorous hand shaking for 120 seconds delays the response somewhat. AVG and Ag(+) further delay the response of mechanically stimulated plants. AVG retards the storage of bending energy but not of stimulus. In gravitropism, graviperception may first stimulate ethylene evolution, which may then influence bending directly, or responses involving ethylene could be more indirect.

  5. Controlled release of ethylene via polymeric films for food packaging

    Science.gov (United States)

    Pisano, Roberto; Bazzano, Marco; Capozzi, Luigi Carlo; Ferri, Ada; Sangermano, Marco

    2015-12-01

    In modern fruit supply chain a common method to trigger ripening is to keep fruits inside special chambers and initiate the ripening process through administration of ethylene. Ethylene is usually administered through cylinders with inadequate control of its final concentration in the chamber. The aim of this study is the development of a new technology to accurately regulate ethylene concentration in the atmosphere where fruits are preserved: a polymeric film, containing an inclusion complex of α-cyclodextrin with ethylene, was developed. The complex was prepared by molecular encapsulation which allows the entrapment of ethylene into the cavity of α-cyclodextrin. After encapsulation, ethylene can be gradually released from the inclusion complex and its release rate can be regulated by temperature and humidity. The inclusion complex was dispersed into a thin polymeric film produced by UV-curing. This method was used because is solvent-free and involves low operating temperature; both conditions are necessary to prevent rapid release of ethylene from the film. The polymeric films were characterized with respect to thermal behaviour, crystalline structure and kinetics of ethylene release, showing that can effectively control the release of ethylene within confined volume.

  6. The involvement of ethylene in regulation of Arabidopsis gravitropism

    Science.gov (United States)

    Li, Ning; Zhu, Lin

    Plant gravitropism is a directional response to gravity stimulus. This response involves a com-plex signaling network. Ethylene, a major plant hormone, has been found to modulate grav-itropism. The biosynthesis of ethylene is induced by the gravi-stimulus and the requirement for ethylene during gravitropism is tissue-dependent. While ethylene plays a modulating role in inflorescence stems, the light-grown hypocotyls of Arabidopsis requires ethylene to achieve a maximum gravicurvature. Because both inhibitory and stimulatory effects of ethylene on gravitropism have been overwhelmingly documented, there is a need to postulate a new theory to consolidate the apparently contradictory results. A dual-and-opposing effects (DOE) theory is therefore hypothesized to address how ethylene is involved in regulation of Arabidopsis grav-itropism, in which it is suggested that both stimulatory and inhibitory effects act on the same organ of a plant and co-exist at the same time in a mutually opposing manner. The final out-come of gravitropic response is determined by the dynamic display between the two opposing effects. A prolonged pretreatment of ethylene promotes the gravitropism in both inflorescence and light-grown hypocotyls, while a short ethylene pretreatment inhibits gravitropism. Gener-ally speaking, the inhibitory effect of ethylene is dominant over the expression of the stimula-tory effect in light-grown hypocotyls, whereas the stimulatory effect is dominant in inflorescence stem. Each effect is also positively correlated with concentrations of ethylene and in a time-dependent manner. The stimulatory effect occurs slowly but continues to react after the removal of ethylene, whereas the inhibitory effect takes place abruptly and diminishes shortly after its removal. Forward genetic screening based on the DOE phenotype of ethylene-treated Arabidop-sis has revealed a novel component in gravity signaling pathway: EGY1 (ethylene-dependent gravitropism-deficient and yellow

  7. Active Region Jets II: Triggering and Evolution of Violent Jets

    Science.gov (United States)

    Sterling, Alphonse C.; Moore, Ronald L.; Falconer, David; Panesar, Navdeep K.; Martinez, Francisco

    2017-08-01

    We study a series of X-ray-bright, rapidly evolving active-region coronal jets outside the leading sunspot of AR 12259, using Hinode/XRT, SDO/AIA and HMI, and IRIS/SJ data. The detailed evolution of such rapidly evolving “violent” jets remained a mystery after our previous investigation of active region jets (Sterling et al. 2016, ApJ, 821, 100). The jets we investigate here erupt from three localized subregions, each containing a rapidly evolving (positive) minority-polarity magnetic-flux patch bathed in a (majority) negative-polarity magnetic-flux background. At least several of the jets begin with eruptions of what appear to be thin (thickness ˜Nature, 523, 437). For some jets strands are difficult/ impossible to detect, perhaps due to their thinness, obscuration by surrounding bright or dark features, or the absence of erupting cool-material minifilaments in those jets. Tracing in detail the flux evolution in one of the subregions, we find bursts of strong jetting occurring only during times of strong flux cancelation. Averaged over seven jetting episodes, the cancelation rate was ~1.5×10^19 Mx/hr. An average flux of ~5×10^18 Mx canceled prior to each episode, arguably building up ~10^28—10^29 ergs of free magnetic energy per jet. From these and previous observations, we infer that flux cancelation is the fundamental process responsible for the pre-eruption buildup and triggering of at least many jets in active regions, quiet regions, and coronal holes.

  8. Jet Suppression Measured in ATLAS

    CERN Document Server

    Citron, Zvi Hirsh; The ATLAS collaboration

    2015-01-01

    In relativistic heavy ion collisions, a hot medium with a high density of unscreened color charges is produced, and jets propagating through this medium are known to suffer energy loss. This results in a lower yield of jets emerging from the medium than expected in the absence of medium effects, and thus modifications of the jet yield are directly sensitive to the energy loss mechanism. Furthermore, jets with different flavor content are expected to be affected by the medium in different ways. Parton showers initiated by quarks tend to have fewer fragments carrying a larger fraction of the total jet energy than those resulting from gluons. In this talk, the latest ATLAS results on single jet suppression will be presented. Measurements of the nuclear modification factor, RAA, for fully reconstructed jets are shown. The rapidity dependence of jet suppression is discussed, which is sensitive to the relative energy loss between quark and gluon jets. New measurements of single hadron suppression out to pT~150 GeV ...

  9. The formation of interstellar jets

    Science.gov (United States)

    Tenorio-Tagle, G.; Canto, J.; Rozyczka, M.

    1988-01-01

    The formation of interstellar jets by convergence of supersonic conical flows and the further dynamical evolution of these jets are investigated theoretically by means of numerical simulations. The results are presented in extensive graphs and characterized in detail. Strong radiative cooling is shown to result in jets with Mach numbers 2.5-29 propagating to lengths 50-100 times their original widths, with condensation of swept-up interstellar matter at Mach 5 or greater. The characteristics of so-called molecular outflows are well reproduced by the simulations of low-Mach-number and quasi-adiabatic jets.

  10. Jet physics at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    S. Seidel

    2002-05-29

    Recent analyses by the CDF and D0 Collaborations of jet data produced in p{bar p} collisions at the Fermilab Tevatron Collider are presented. These include new studies of the inclusive jet production cross section, a measurement of the strong coupling constant, the first measurement of subjet multiplicity of quark and gluon jets, examination of ratios of multijet cross sections and their implications for choice of renormalization scale, and a study of charged jet evolution and energy flow in the underlying event. The results are compared to theoretical predictions.

  11. [Decontamination of some spices by ethylene oxide. Development of 2-chloroethanol and ethylene glycol during the preservation].

    Science.gov (United States)

    Chaigneau, M; Muraz, B

    1993-01-01

    After the disinfection by ethylene oxide and storage by ethylene oxide in definite conditions of 16 spices (parsley, chervil, tarragone, chive, thyme, rosemary, coriander, nutmeg, mace, cinnamon, allspices, clove, pepper), the authors observed the fast loss of residual ethylene oxide and ethyleneglycol. On the contrary, the persistence of 2-chloroethanol was followed up for 6 months. They turn their attention to the toxicity of this compound to ensure the protection of customers.

  12. Numerical investigation of mixing in parallel jets

    Energy Technology Data Exchange (ETDEWEB)

    Durve, Ameya [Department of Chemical Engineering, Institute of Chemical Technology, Matunga, Mumbai 400019 (India); Patwardhan, Ashwin W., E-mail: aw.patwardhan@ictmumbai.edu.in [Department of Chemical Engineering, Institute of Chemical Technology, Matunga, Mumbai 400019 (India); Banarjee, Indraneel; Padmakumar, G.; Vaidyanathan, G. [Experimental thermal Hydraulics Section, Separation Technology and Hydraulics Division, Fast Reactor Technology Group, Indira Gandhi Centre for Atomic Research, Kalpakkam 603102 (India)

    2012-01-15

    Highlights: Black-Right-Pointing-Pointer The effect of adjacent third jet on the mixing of two plane parallel jets is studied using computational fluid dynamics (CFD). Black-Right-Pointing-Pointer Validation of CFD model with experimental data. Black-Right-Pointing-Pointer Comparison of mixing behavior of two jet flow and three jet flow. Black-Right-Pointing-Pointer Three jet systems provide more efficient mixing than single jet and two jet systems. Black-Right-Pointing-Pointer Turbulent fluctuations occurring in the two jet flow are smaller as compared to the three jet flow. - Abstract: A system of parallel jets is widely encountered in many industrial applications. Wide spread applications necessitate the study of the basic mixing phenomenon of parallel jets. In the present study, the mixing phenomenon in the two jet flow and the three jet flow has been studied numerically by solving the Reynolds Averaged Navier Stokes equations. The results predicted by the Reynolds stress model compare well with the experimental data of axial velocity and shear stress available in literature. An attempt has been made to predict the critical mixing regions such as the merge point and the combine point by correlating them with jet spacing and jet exit conditions. A comparison between single jet, two jet and three jet systems has been carried out to evaluate the effect of presence of the second and the third jet on the mixing phenomenon and turbulent fluctuations.

  13. The effect of nitrate on ethylene biofiltration

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Sang-Hun, E-mail: lee323@alumni.purdue.edu [Department of Agricultural and Biological Engineering, Purdue University, 225 South University St., West Lafayette, 47907-2093 IN (United States); Li, Congna; Heber, Albert J. [Department of Agricultural and Biological Engineering, Purdue University, 225 South University St., West Lafayette, 47907-2093 IN (United States)

    2012-11-30

    Highlights: Black-Right-Pointing-Pointer Ethylene biofiltration strongly depends on nitrate concentrations and media types. Black-Right-Pointing-Pointer We examine reduced N supply can increase ethylene removals in biofilters. Black-Right-Pointing-Pointer Perlite medium is better for ethylene biofiltration than activated carbon medium. - Abstract: This study investigated the effects of filter media types and nitrate (NO{sub 3}{sup -}) concentrations in nutrient solutions on C{sub 2}H{sub 4} biofiltration. A new nutrient solution with zero NO{sub 3}{sup -} concentration was supplied to two perlite-bed biotrickling filters, two perlite-bed biofilters, and two GAC (Granular Activated Carbon)-bed biofilters, while the other with 2 g L{sup -1} of NO{sub 3}{sup -} was used for the other two GAC biofilters. All reactors underwent a total test duration of over 175 days with an EBRT (Empty Bed Residence Time) of 30 s, inlet gas flow rate of 7 L min{sup -1}, and inlet C{sub 2}H{sub 4} concentrations of 20-30 mg m{sup -3}. NO{sub 3}{sup -} concentration and media type significantly affected the C{sub 2}H{sub 4} removal efficiencies in all types of biofiltration. The perlite media with no NO{sub 3}{sup -} achieved C{sub 2}H{sub 4} removal efficiencies 10-50% higher than the others. A NO{sub 3}{sup -} concentration as high as 2 g L{sup -1} in the original nutrient solution may act as an inhibitor that suppresses the growth or activity of C{sub 2}H{sub 4} degraders. In addition, the perlite media resulted in higher C{sub 2}H{sub 4} removal efficiencies than GAC media, because the hydrophilic surface of the perlite leads to a higher moisture content and thus to favorable microbial growth.

  14. Jet simulations and gamma-ray burst afterglow jet breaks

    NARCIS (Netherlands)

    van Eerten, H. J.; Meliani, Z.; Wijers, R.A.M.J.; Keppens, R.

    2010-01-01

    The conventional derivation of the gamma-ray burst afterglow jet break time uses only the blast wave fluid Lorentz factor and therefore leads to an achromatic break. We show that in general gamma-ray burst afterglow jet breaks are chromatic across the self-absorption break. Depending on circumstance

  15. Jet simulations and gamma-ray burst afterglow jet breaks

    NARCIS (Netherlands)

    van Eerten, H. J.; Meliani, Z.; Wijers, Ramj; Keppens, R.

    2011-01-01

    The conventional derivation of the gamma-ray burst afterglow jet break time uses only the blast wave fluid Lorentz factor and therefore leads to an achromatic break. We show that in general gamma-ray burst afterglow jet breaks are chromatic across the self-absorption break. Depending on circumstance

  16. Jet simulations and gamma-ray burst afterglow jet breaks

    NARCIS (Netherlands)

    van Eerten, H.J.; Meliani, Z.; Wijers, R.A.M.J.; Keppens, R.

    2012-01-01

    The conventional derivation of the gamma-ray burst afterglow jet break time uses only the blast wave fluid Lorentz factor and therefore leads to an achromatic break. We show that in general gamma-ray burst afterglow jet breaks are chromatic across the self-absorption break. Depending on circumstance

  17. Jet simulations and gamma-ray burst afterglow jet breaks

    NARCIS (Netherlands)

    van Eerten, H. J.; Meliani, Z.; Wijers, Ramj; Keppens, R.

    2011-01-01

    The conventional derivation of the gamma-ray burst afterglow jet break time uses only the blast wave fluid Lorentz factor and therefore leads to an achromatic break. We show that in general gamma-ray burst afterglow jet breaks are chromatic across the self-absorption break. Depending on

  18. Jet simulations and gamma-ray burst afterglow jet breaks

    NARCIS (Netherlands)

    van Eerten, H. J.; Meliani, Z.; Wijers, R.A.M.J.; Keppens, R.

    2010-01-01

    The conventional derivation of the gamma-ray burst afterglow jet break time uses only the blast wave fluid Lorentz factor and therefore leads to an achromatic break. We show that in general gamma-ray burst afterglow jet breaks are chromatic across the self-absorption break. Depending on

  19. ADVANCED CONTROL FOR A ETHYLENE REACTOR

    Directory of Open Access Journals (Sweden)

    Dumitru POPESCU

    2017-06-01

    Full Text Available The main objective of this work is the design and implementation of control solutions for petrochemical processes, namely the control and optimization of a pyrolysis reactor, the key-installation in the petrochemical industry. We present the technological characteristics of this petrochemical process and some aspects about the proposed control system solution for the ethylene plant. Finally, an optimal operating point for the reactor is found, considering that the process has a nonlinear multi-variable structure. The results have been implemented on an assembly of pyrolysis reactors on a petrochemical platform from Romania.

  20. Hadron jets in perspective

    Energy Technology Data Exchange (ETDEWEB)

    Quigg, C.

    1982-11-01

    The subject of hadron jet studies, to judge by the work presented at this workshop, is a maturing field which is still gathering steam. The very detailed work being done in lepton-lepton and lepton-hadron collisions, the second-generation measurements being carried out at Fermilab, the CERN SPS, and the ISR, and the very high energy hard scatterings being observed at the CERN Collider all show enormous promise for increased understanding. Perhaps we shall yet reach that long-sought nirvana in which high-p/sub perpendicular/ collisions become truly simple.

  1. Jet Vectoring Control Using a Novel Synthetic Jet Actuator

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A primary air jet vectoring control system with a novel synthetic jet actuator (SJA) is presented and simulated numerically. The results show that, in comparison with an existing traditional synthetic jet actuator, which is able to perform the duty of either "push" or "pull", one novel synthetic jet actuator can fulfill both "push" and "pull" functions to vector the primary jet by shifting a slide block inside it. Therefore, because the new actuator possesses greater efficiency, it has potentiality to replace the existing one in various applications, such as thrust vectoring and the reduction of thermal signature. Moreover, as the novel actuator can fulfill those functions that the existing one can not, it may well be expected to popularize it into more flow control systems.

  2. Protostellar jets the best laboratories for investigating astrophysical jets

    CERN Document Server

    De Gouveia dal Pino, E M

    1995-01-01

    Highly collimated supersonic jets are observed to emerge from a wide variety of astrophysical objects, ranging from Active Nuclei of Galaxies (AGN's) to Young Stellar Objects (YSOs) within our own Galaxy. Despite their different physical scales (in size, velocity, and amount of energy transported), they have strong morphological similarities. Thanks to the proximity and relatively small timescales, which permit direct observations of evolutionary changes, YSO jets are, perhaps, the best laboratories for cosmic jet investigation. In this lecture, the formation, structure, and evolution of the YSO jets are reviewed with the help of observational information, MHD and purely hydrodynamical modeling, and numerical simulations. Possible applications of the models to AGN jets are also addressed.

  3. Ethylene production and peroxidase activity in aphid-infested barley.

    Science.gov (United States)

    Argandoña, V H; Chaman, M; Cardemil, L; Muñoz, O; Zúñiga, G E; Corcuera, L J

    2001-01-01

    The purpose of this work was to investigate whether ethylene is involved in the oxidative and defensive responses of barley to the aphids Schizaphis graminum (biotype C) and Rhopalophum padi. The effect of aphid infestation on ethylene production was measured in two barley cultivars (Frontera and Aramir) that differ in their susceptibility to aphids. Ethylene evolution was higher in plants infested for 16 hr than in plants infested for 4 hr in both cultivars. Under aphid infestation, the production of ethylene was higher in cv. Frontera than in Aramir, the more aphid susceptible cultivar. Ethylene production also increases with the degree of infestation. Maximum ethylene evolution was detected after 16 hr when plants were infested with 10 or more aphids. Comparing the two species of aphids, Schizaphis graminum induced more ethylene evolution than Rhopalosiphum padi. Infestation with S. graminum increased hydrogen peroxide content and total soluble peroxidase activity in cv. Frontera, with a maximum level of H2O2 observed after 20 min of infestation and the maximum in soluble peroxidase activity after 30 min of infestation. When noninfested barley seedlings from cv. Frontera were exposed to ethylene, an increase in hydrogen peroxide and in total peroxidase activity was detected at levels similar to those of infested plants from cv. Frontera. When noninfested plants were treated with 40 ppm of ethylene, the maximum levels of H2O2 and soluble peroxidase activity were at 10 and 40 min, respectively. Ethylene also increased the activity of both cell-wall-bound peroxidases types (ionically and covalently bound), comparable with infestation. These results suggest that ethylene is involved in the oxidative responses of barley plants induced by infestation.

  4. CONTROL OF TWO DIMENSIONAL JETS USING MINIATURE ZERO MASS FLUX JETS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Zero mass flux jets, synthesized by acoustic actuators, have been used for the purpose of jet mixing enhancement and jet vectoring. Zero mass flux jets composed of entirely entrained fluid allow momentum transfer into the embedding flow. In the present experiments, miniature-scale high aspect ratio actuator jets are placed along the long sides and near the exit plane of a primary two-dimensional jet. In different modes, the primary jet can be vectored either towards or away from the actuator jets and the jet mixing is enhanced. The disturbance of the excitation frequency is developed while the unstable frequency of the primary jet is completely suppressed.

  5. Ignition by Hot Transient Jets in Confined Mixtures of Gaseous Fuels and Air

    Directory of Open Access Journals (Sweden)

    Abdullah Karimi

    2016-01-01

    Full Text Available Ignition of a combustible mixture by a transient jet of hot reactive gas is important for safety of mines, prechamber ignition in IC engines, detonation initiation, and novel constant-volume combustors. The present work is a numerical study of the hot jet ignition process in a long constant-volume combustor (CVC that represents a wave rotor channel. The hot jet of combustion products from a prechamber is injected through a converging nozzle into the main CVC chamber containing a premixed fuel-air mixture. Combustion in a two-dimensional analogue of the CVC chamber is modeled using a global reaction mechanism, a skeletal mechanism, or a detailed reaction mechanism for three hydrocarbon fuels: methane, propane, and ethylene. Turbulence is modeled using the two-equation SST k-ω model, and each reaction rate is limited by the local turbulent mixing timescale. Hybrid turbulent-kinetic schemes using some skeletal reaction mechanisms and detailed mechanisms are good predictors of the experimental data. Shock wave traverse of the reaction zone is seen to significantly increase the overall reaction rate, likely due to compression heating, as well as baroclinic vorticity generation that stirs and mixes reactants and increases flame area. Less easily ignitable methane mixture is found to show slower initial reaction and greater dependence on shock interaction than propane and ethylene.

  6. Momentum transfer by astrophysical jets

    CERN Document Server

    Chernin, L M; De Gouveia dal Pino, E M; Benz, W

    1994-01-01

    We have used 3-D smoothed particle hydrodynamical simulations to study the basic properties of the outflow that is created by a protostellar jet in a dense molecular cloud. The dynamics of the jet/cloud interaction is strongly affected by the cooling in the shocked gas behind the bow shock at the head of the jet. We show that this cooling is very rapid, with the cooling distance of the gas much less than the jet radius. Thus, although ambient gas is initially driven away from the jet axis by the high thermal pressure odf the post-shock gas, rapid cooling reduces the pressure and the outflow subsequently evolves in a momentum-conserving snowplow fashion. The velocity of the ambient gas is high in the vicinity of the jet head, but decreases rapidly as more material is swept up. Thus, this type of outflow produces extremely high velocity clumps of post shock gas which resemble the features seen in outflows. We have investigated the transfer of momentum from the jet to the ambient medium as a function of the jet ...

  7. The Highest Redshift Relativistic Jets

    Energy Technology Data Exchange (ETDEWEB)

    Cheung, C.C.; Stawarz, L.; Siemiginowska, A.; Harris, D.E; Schwartz, D.A.; Wardle, J.F.C.; Gobeille, D.; Lee, N.P.

    2007-12-18

    We describe our efforts to understand large-scale (10's-100's kpc) relativistic jet systems through observations of the highest-redshift quasars. Results from a VLA survey search for radio jets in {approx} 30 z > 3.4 quasars are described along with new Chandra observations of 4 selected targets.

  8. Jet charge at the LHC.

    Science.gov (United States)

    Krohn, David; Schwartz, Matthew D; Lin, Tongyan; Waalewijn, Wouter J

    2013-05-24

    Knowing the charge of the parton initiating a light-quark jet could be extremely useful both for testing aspects of the standard model and for characterizing potential beyond-the-standard-model signals. We show that despite the complications of hadronization and out-of-jet radiation such as pileup, a weighted sum of the charges of a jet's constituents can be used at the LHC to distinguish among jets with different charges. Potential applications include measuring electroweak quantum numbers of hadronically decaying resonances or supersymmetric particles, as well as standard model tests, such as jet charge in dijet events or in hadronically decaying W bosons in tt[over ¯] events. We develop a systematically improvable method to calculate moments of these charge distributions by combining multihadron fragmentation functions with perturbative jet functions and pertubative evolution equations. We show that the dependence on energy and jet size for the average and width of the jet charge can be calculated despite the large experimental uncertainty on fragmentation functions. These calculations can provide a validation tool for data independent of Monte Carlo fragmentation models.

  9. Core shifts in blazar jets

    CERN Document Server

    Zdziarski, Andrzej A; Pjanka, Patryk; Tchekhovskoy, Alexander

    2014-01-01

    We study the effect of core shift in jets, which is the dependence of the position of the jet radio core on the frequency. We derive a new method to measure the jet magnetic field based on both the value of the shift and the observed flux, which compliments the standard method assuming equipartition. Using both methods, we re-analyse the blazar sample of Zamaninasab et al. We find that equipartition is satisfied only if the jet opening angle in the radio core region is close to the values found observationally, $\\simeq$0.1--0.2 divided by the bulk Lorentz factor, $\\Gamma_{\\rm j}$. Larger values, e.g., $1/\\Gamma_{\\rm j}$, would imply very strong departures from equipartition. A small jet opening angle implies in turn the magnetization parameter of $\\ll 1$. We determine the jet magnetic flux taking this effect into account. We find that the average jet magnetic flux is compatible with the model of jet formation due to black-hole spin energy extraction and accretion being magnetically arrested. We calculate the ...

  10. Magnetic Field Topology in Jets

    Science.gov (United States)

    Gardiner, T. A.; Frank, A.

    2000-01-01

    We present results on the magnetic field topology in a pulsed radiative. jet. For initially helical magnetic fields and periodic velocity variations, we find that the magnetic field alternates along the, length of the jet from toroidally dominated in the knots to possibly poloidally dominated in the intervening regions.

  11. Dense Hypervelocity Plasma Jets

    Science.gov (United States)

    Case, Andrew; Witherspoon, F. Douglas; Messer, Sarah; Bomgardner, Richard; Phillips, Michael; van Doren, David; Elton, Raymond; Uzun-Kaymak, Ilker

    2007-11-01

    We are developing high velocity dense plasma jets for fusion and HEDP applications. Traditional coaxial plasma accelerators suffer from the blow-by instability which limits the mass accelerated to high velocity. In the current design blow-by is delayed by a combination of electrode shaping and use of a tailored plasma armature created by injection of a high density plasma at a few eV generated by arrays of capillary discharges or sparkgaps. Experimental data will be presented for a complete 32 injector gun system built for driving rotation in the Maryland MCX experiment, including data on penetration of the plasma jet through a magnetic field. We present spectroscopic measurements of plasma velocity, temperature, and density, as well as total momentum measured using a ballistic pendulum. Measurements are in agreement with each other and with time of flight data from photodiodes and a multichannel PMT. Plasma density is above 10^15 cm-3, velocities range up to about 100 km/s. Preliminary results from a quadrature heterodyne HeNe interferometer are consistent with these results.

  12. LHCb; LHCb Jet Reconstruction

    CERN Multimedia

    Augusto, O

    2012-01-01

    The Large Hadron Collider (LHC) is the most powerful particle accelerator in the world. It has been designed to collide proton beams at an energy up to 14 TeV in the center of mass. In 2011, the data taking was done with a center of mass energy of 7 TeV, the instant luminosity has reached values greater than $4 \\times 10^{32} cm^{-2} s^{-1}$ and the integrated luminosity reached the value of 1.02 $fb^{-1}$ on the LHCb. The jet reconstruction is fundamental to observe events that can be used to test pertubative QCD (pQCD). It also provides a way to observe standard model channels and searches for new physics like SUSY. The anti-kt algorithm is a jet reconstruction algorithm that is based on the distance of the particles on the space $\\eta \\times \\phi$ and on the transverse momentum of particles. To maximize the energy resolution all information about the trackers and the calo...

  13. Hydrophilic poly(ethylene oxide)-aramide segmented block copolymers

    NARCIS (Netherlands)

    Araichimani, A.; ten Hoopen, Hermina W.M.; Gaymans, R.J.

    2009-01-01

    The present paper discusses block copolymers with segments of either poly(ethylene oxide), poly(propylene oxide), or mixtures of poly(ethylene oxide)/poly(propylene oxide) and monodisperse aramide segments. The length of the polyether segments as well as the concentration of polyethylene oxide was

  14. Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide (Final Report)

    Science.gov (United States)

    EPA has finalized its Evaluation of the Inhalation Carcinogenicity of Ethylene Oxide. This assessment addresses the potential carcinogenicity from long-term inhalation exposure to ethylene oxide. Now final, this assessment updates the carcinogenicity information in EPA’s 1985 Hea...

  15. 21 CFR 177.1310 - Ethylene-acrylic acid copolymers.

    Science.gov (United States)

    2010-04-01

    ... (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) INDIRECT FOOD ADDITIVES: POLYMERS Substances for Use as... this section are not applicable to ethylene-acrylic acid copolymers used in food-packaging adhesives... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene-acrylic acid copolymers. 177.1310...

  16. Price dynamics of crude oil and the regional ethylene markets

    Energy Technology Data Exchange (ETDEWEB)

    Masih, Mansur [Department of Finance and Economics, Center of Research Excellence in Renewable Energy, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Algahtani, Ibrahim [Department of Finance and Economics, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); De Mello, Lurion [Faculty of Business and Economics, Macquarie University, Sydney (Australia)

    2010-11-15

    This paper is the first attempt to investigate: (1) is the crude oil (WTI) price significantly related to the regional ethylene prices in the Naphtha intensive ethylene markets of the Far East, North West Europe, and the Mediterranean? (2) What drives the regional ethylene prices? The paper is motivated by the recent and growing debate on the lead-lag relationship between crude oil and ethylene prices. Our findings, based on the long-run structural modelling approach of Pesaran and Shin, and subject to the limitations of the study, tend to suggest: (1) crude oil (WTI) price is cointegrated with the regional ethylene prices (2) our within-sample error-correction model results tend to indicate that although the ethylene prices in North West Europe and the Mediterranean were weakly endogenous, the Far East ethylene price was weakly exogenous both in the short and long term. These results are consistent, during most of the period under review (2000.1-2006.4) with the surge in demand for ethylene throughout the Far East, particularly in China and South Korea. However, during the post-sample forecast period as evidenced in our variance decompositions analysis, the emergence of WTI as a leading player as well, is consistent with the recent surge in WTI price (fuelled mainly, among others, by the strong hedging activities in the WTI futures/options and refining tightness) reflecting the growing importance of input cost in determining the dynamic interactions of input and product prices. (author)

  17. Defining sale ethylene for long term storage of tulip bulbs

    NARCIS (Netherlands)

    Wild, de H.P.J.; Peppelenbos, H.W.; Dijkstra, M.H.G.E.; Gude, H.

    2002-01-01

    The maximum ethylene level that can be permitted in storage rooms, without causing damage to tulip bulbs, is not exactly known. Therefore, a zero-tolerance for the presence of ethylene during storage of tulip bulbs is common practice. This results in excessive ventilation and coherent large energy

  18. Defining sale ethylene for long term storage of tulip bulbs

    NARCIS (Netherlands)

    Wild, de H.P.J.; Peppelenbos, H.W.; Dijkstra, M.H.G.E.; Gude, H.

    2002-01-01

    The maximum ethylene level that can be permitted in storage rooms, without causing damage to tulip bulbs, is not exactly known. Therefore, a zero-tolerance for the presence of ethylene during storage of tulip bulbs is common practice. This results in excessive ventilation and coherent large energy c

  19. Abscission of mango fruitlets as influenced by enhanced ethylene biosynthesis.

    Science.gov (United States)

    Nunez-Elisea, R; Davenport, T L

    1986-12-01

    Experiments were conducted on developing fruitlet explants of two mango (Mangifera indica L.) cultivars to establish the source and dynamics of ethylene production prior to and during fruitlet abscission. Abscission of all fruits in the samples occurred at approximately 86 and 74 hours postharvest in ;Keitt' and ;Tommy Atkins,' respectively. Increased abscission began 26 hours from harvest and was preceded by enhanced ethylene synthesis. Enhanced ethylene production initiated approximately 48 hours prior to abscission and increased to a maximum near the time of fruitlet abscission. The seed produced the highest amount of ethylene on a per gram fresh weight basis. The pericarp, however, was the main source of ethylene on an absolute basis, since it represented more than 85% of total fruitlet weight. Pedicels containing the abscission zone produced no detectable ethylene prior to or at the moment of abscission. Fumigation of ;Tommy Atkins' fruitlets with 1, 15, or 100 microliters per liter ethylene accelerated abscission by 24 to 36 hours in comparison with unfumigated controls. Diffusion of ethylene from distal fruitlet tissues to the abscission zone triggers the events leading to separation of the fruit from the tree.

  20. 基于二阶矩封闭湍流模型的非预混湍流火焰的数值模拟%Numerical Simulation of the Turbulent Nonpremixed Flame with Second-Moment Turbulence Closure Models

    Institute of Scientific and Technical Information of China (English)

    李国岫; Roekaerts Dirk

    2004-01-01

    A numerical simulation of a bluff-body stabilized nonpremixed flame has been performed with second-moment turbulence closure(SMTC) models.To clarify the applicability of the existing-SMTC models in this complex flame, several typical SMTC models ,including LRR-IP model, JM model,SSC model as well as two modified LRR-IP mode, have been applied and evaluated in the numerical simulation of a bluff-body flame. Some of the above-mentioned SMTC models cannot provide overall satisfactory predictions for this challenging test. The difference in performance between the various SMTC models is quite significant. In the present study, the equilibrium chemistry model is employed and an assumed-shape beta function PDF approach is used to represent the interaction between turbulence and chemistry. It can be concluded that the modified LRR-IP models as well as SSG model are superior to other SMTC models in the turbulent nonpremixed bluff-body stabilized flame.%应用二阶矩封闭湍流模型进行了湍流非预混钝体稳定火焰数值模拟的研究.应用LRR-IP模型,JM模型,SSG模型以及两个修正后的LRR-IP模型等二阶矩封闭湍流模型,进行了钝体稳定火焰数值模拟的研究.对于复杂的钝体稳定火焰,一些模型无法给出令人满意的结果,而且不同模型的结果差异很大.在研究中,湍流燃烧模型采用了化学平衡模型和假设PDF模型.研究结果表明,对于钝体稳定火焰,SSG模型以及两个修正后的LRR-IP模型要优于其他几个二阶矩封闭湍流模型.

  1. False hyperlactatemia in life-threatening ethylene glycol poisoning.

    Science.gov (United States)

    Riquier, T; Geri, G; Mongardon, N; Bourgogne, E; Pène, F

    2014-04-01

    Ethylene glycol poisoning is rare, but prompt diagnosis is crucial, in order to initiate specific treatments. Herein, we report the case of a patient who was admitted to ICU for coma and extreme metabolic acidosis with unexpected hyperlactatemia on initial ICU blood gas analyzer. Ethylene glycol poisoning was diagnosed, and hyperlactatemia was ruled out on a blood sample sent to the biochemistry department. Interference of blood gas analyzers lactate electrodes with metabolites of ethylene glycol were the source of this apparent hyperlactatemia. Symptoms gradually improved and false hyperlactatemia resolved after renal replacement therapy and fomepizole administration. Time course of ethylene glycol concentration showed similar evolution. After initial confirmation of ethylene glycol presence, this biological interference could thus be used as a surrogate of costly and highly specialised dosages. Copyright © 2014 Société française d’anesthésie et de réanimation (Sfar). Published by Elsevier SAS. All rights reserved.

  2. Understanding tantalum-catalyzed ethylene trimerization: When things go wrong

    KAUST Repository

    Chen, Yin

    2013-06-07

    Ethylene oligomerization to linear low-molecular-mass α-olefins is an open industrial challenge. Ta-based catalysts are promising systems, but the unclear understanding of their behavior prevents systematic advances in the field. We demonstrate here that a well-defined (î -SiO)3Ta III species is able to promote ethylene oligo-/polymerization without any cocatalyst, confirming that the active species in Ta systems corresponds to a TaIII species. DFT calculations on a series of Ta systems ranging from ethylene trimerization to ethylene polymerization catalysts highlight the key factors controlling their experimental behavior. Comparison of these Ta systems allows one to set general rules for the rational development of new ethylene Ta oligomerization catalysts. © 2013 American Chemical Society.

  3. Elucidating Jet Energy Loss Using Jets: Prospects from ATLAS

    CERN Document Server

    Grau, N

    2009-01-01

    The details of jet energy loss, as measured at RHIC with single particles and mu lti-particle correlations, are unresolved, and new experimental measurements are necessary in order to shed light on the mechanism and behavior of energy loss. Utilizing the ATLAS electromagnetic and hadronic calorimetry, full jet reconstru ction in a heavy ion environment will be performed over a wide range of $p_T$ an d rapidity. With fully reconstructed jets, new and more sensitive probes are ava ilable to test models of energy loss. In this talk, we present a series of obser vables such as the jet $R_{AA}$, the transverse momentum, $j_T$, spectrum of fra gments, the fragmentation function $D(z)$, jet shapes, and di-jet correlations, that aresensitive to perturbative and non-perturbative energy loss. We also disc uss the current level of sensitivity to expected modifications using several dif ferent jet algorithms, the cone, $k_T$, and anti-$k_T$ algorithms.

  4. Ethylene production throughout growth and development of plants

    Science.gov (United States)

    Wheeler, Raymond M.; Peterson, Barbara V.; Stutte, Gary W.

    2004-01-01

    Ethylene production by 10 or 20 m2 stands of wheat, soybean, lettuce, potato, and tomato was monitored throughout growth and development in an atmospherically closed plant chamber. Chamber ethylene levels varied among species and rose during periods of canopy expansion and rapid growth for all species. Following this, ethylene levels either declined during seed fill and maturation for wheat and soybean, or remained relatively constant for potato and tomato (during flowering and early fruit development). Lettuce plants were harvested during rapid growth and peak ethylene production. Chamber ethylene levels increased rapidly during tomato ripening, reaching concentrations about 10 times that measured during vegetative growth. The highest ethylene production rates during vegetative growth ranged from 1.6 to 2.5 nmol m-2 d-1 during rapid growth of lettuce and wheat stands, or about 0.3 to 0.5 nmol g-1 fresh weight per hour. Estimates of stand ethylene production during tomato ripening showed that rates reached 43 nmol m-2 d-1 in one study and 93 nmol m-2 d-1 in a second study with higher lighting, or about 50x that of the rate during vegetative growth of tomato. In a related test with potato, the photoperiod was extended from 12 to 24 hours (continuous light) at 58 days after planting (to increase tuber yield), but this change in the environment caused a sharp increase in ethylene production from the basal rate of 0.4 to 6.2 nmol m-2 d-1. Following this, the photoperiod was changed back to 12 h at 61 days and ethylene levels decreased. The results suggest three separate categories of ethylene production were observed with whole stands of plants: 1) production during rapid vegetative growth, 2) production during climacteric fruit ripening, and 3) production from environmental stress.

  5. Ethylene and rooting of mung bean cuttings. The role of auxin induced ethylene synthesis and phase-dependent effects

    NARCIS (Netherlands)

    Klerk, de G.J.M.; Hanecakova, J.

    2008-01-01

    We have re-examined the role of ethylene during rooting of mung bean cuttings. Cuttings were treated for 5 days with a low or a high concentration of NAA (naphthaleneacetic acid). During this 5 days period, we also applied STS (silverthiosulfate, an inhibitor of ethylene action) or ACC (1-aminocyclo

  6. Research tools: ethylene preparation. In: Chi-Kuang Wen editor. Ethylene in plants. Springer Netherlands. Springer Link

    Science.gov (United States)

    Ethylene is a plant hormone that regulates many aspects of plant growth and development, germination, fruit ripening, senescence, sex determination, abscission, defense, gravitropism, epinasty, and more. For experimental purposes, one needs to treat plant material with ethylene and its inhibitors t...

  7. Ethylene and rooting of mung bean cuttings. The role of auxin induced ethylene synthesis and phase-dependent effects

    NARCIS (Netherlands)

    Klerk, de G.J.M.; Hanecakova, J.

    2008-01-01

    We have re-examined the role of ethylene during rooting of mung bean cuttings. Cuttings were treated for 5 days with a low or a high concentration of NAA (naphthaleneacetic acid). During this 5 days period, we also applied STS (silverthiosulfate, an inhibitor of ethylene action) or ACC (1-aminocyclo

  8. Resonance Production in Jet

    CERN Document Server

    Markert, Christina

    2007-01-01

    Hadronic resonances with short life times and strong coupling to the dense medium may exhibit mass shifts and width broadening as signatures of chiral symmetry restoration at the phase transition between hadronic and partonic matter. Resonances with different lifetimes are also used to extract information about the time evolution and temperature of the expanding hadronic medium. In order to collect information about the early stage (at the phase transition) of a heavy-ion collision, resonances and decay particles which are unaffected by the hadronic medium have to be used. We explore a possible new technique to extract signals from the early stage through the selection of resonances from jets. A first attempt of this analysis, using the reconstructed $\\phi$(1020) from 200 GeV Au+Au collisions in STAR, is presented.

  9. Impinging Jet Dynamics

    CERN Document Server

    Chen, Xiaodong

    2012-01-01

    In this fluid dynamics video, Ray-tracing data visualization technique was used to obtain realistic and detailed flow motions during impinging of two liquid jets. Different patterns of sheet and rim configurations were presented to shed light into the underlying physics, including liquid chain, closed rim, open rim, unstable rim and flapping sheet. In addition, stationary asymmetrical waves were observed and compared with existing theories. The generation of stationary capillary wave in respect to the liquid rim were explained by the classic shallow water wave theory. The atomization process caused by development of the impact waves were observed in detail, including fragmentation of liquid sheet, formation of liquid ligaments, and breakup of ligament into droplet. The locking-on feature of the wavelength of impact wave were also found to be similar to that of perturbed free shear layers.

  10. Producing the Ethylene Signal: Regulation and Diversification of Ethylene Biosynthetic Enzymes.

    Science.gov (United States)

    Booker, Matthew A; DeLong, Alison

    2015-09-01

    Strictly controlled production of ethylene gas lies upstream of the signaling activities of this crucial regulator throughout the plant life cycle. Although the biosynthetic pathway is enzymatically simple, the regulatory circuits that modulate signal production are fine tuned to allow integration of responses to environmental and intrinsic cues. Recently identified posttranslational mechanisms that control ethylene production converge on one family of biosynthetic enzymes and overlay several independent reversible phosphorylation events and distinct mediators of ubiquitin-dependent protein degradation. Although the core pathway is conserved throughout seed plants, these posttranslational regulatory mechanisms may represent evolutionarily recent innovations. The evolutionary origins of the pathway and its regulators are not yet clear; outside the seed plants, numerous biochemical and phylogenetic questions remain to be addressed.

  11. Novel gaseous ethylene binding inhibitor prevents ethylene effects in potted flowering plants

    Energy Technology Data Exchange (ETDEWEB)

    Serek, M.; Reid, M.S. (Univ. of California, Davis, CA (United States). Dept. of Environmental Horticulture); Sisler, E.C. (North Carolina State Univ., Raleigh, NC (United States). Dept. of Biochemistry)

    1994-11-01

    A 6-hour fumigation of flowering Begonia xelatior hybrida Fotsch. Najada' and Rosa', B. xtuberhybrida Voss. Non-Stop', Kalanchoe blossfeldiana Poelln. Tropicana', and Rosa hybrida L. Victory Parade' plants with 1-MCP, (formerly designated as SIS-X), a gaseous nonreversible ethylene binding inhibitor, strongly inhibited exogenous ethylene effects such as bud and flower drop, leaf abscission, and accelerated flower senescence. The inhibitory effects of 1-MCP increased linearly with concentration, and at 20 nl-liter[sup [minus]1] this compound gave equal protection to that afforded by spraying the plants with a 0.5 STS mM solution. Chemical names used: 1-methylcyclopropene (1-MCP), silver thiosulfate (STS).

  12. Self-diffusion coefficients of hexamethylphosphoric triamide and ethylene glycol molecules in ethylene glycol solutions

    Science.gov (United States)

    Idiyatullin, Z. Sh.; Solonina, I. A.; Rodnikova, M. N.; Sirotkin, D. A.

    2017-08-01

    The self-diffusion coefficients of the molecules of hexamethylphosphoric triamide (HMPT) and ethylene glycol (EG) in ethylene glycol solutions in the concentration range 0-16 mol % HMPT and molecules of pure HMPT in the temperature range 30-60°C are measured by the spin-echo method on protons. Activation energies for the corresponding processes of self-diffusion were calculated. The obtained data are discussed in terms of solvophobic effects in the EG-HMPT system. The self-diffusion coefficient of pure HMPT was 0.344 × 10-5 cm2/s at 33.2°C, and the self-diffusion activation energy was 3.86 kcal/mol.

  13. Collection of an electrospinning jet

    Science.gov (United States)

    Han, Tao; Reneker, Darrell

    2006-03-01

    Electrospinning [1, 2] of polymer nanofibers involves an electrically driven bending instability of the elongating jet. If the jet is collected on a stationary surface immediately before or after the bending instability occurs, the jet buckles as it stops. Bending and buckling are distinct phenomena. The determination of the behavior of the jet path in the vicinity of the onset of the first bending instability is important for the orderly collection of the nanofiber. Precise adjustment of the fluid flow, the electrical current, and the shape of the region from which the jet issued, produced a very stable jet which was observed with a high frame rate, short exposure time camera. The fluid jet and the resulting nanofibers were collected on a solid, electrically conducting substrate which was moved laterally, and simultaneously, away from the tip. This collected material preserved a record of the straight segment and the bending and buckling instabilities with a minimum of overlapping. The occurrence of a second bending instability was sometimes observed in the dry fiber. 1. Doshi, J.; Reneker, D.H., Journal of Electrostatics; 35, 151, 1995 2. Reneker, D.H. ;Yarin,A.L.Fong, H.; Koombhongse, S., Journal of Applied Physics, 87, 4531, 2000

  14. Magnetic Dissipation in Relativistic Jets

    Directory of Open Access Journals (Sweden)

    Yosuke Mizuno

    2016-10-01

    Full Text Available The most promising mechanisms for producing and accelerating relativistic jets, and maintaining collimated structure of relativistic jets involve magnetohydrodynamical (MHD processes. We have investigated the magnetic dissipation mechanism in relativistic jets via relativistic MHD simulations. We found that the relativistic jets involving a helical magnetic field are unstable for the current-driven kink instability, which leads to helically distorted structure in relativistic jets. We identified the regions of high current density in filamentary current sheets, indicative of magnetic reconnection, which are associated to the kink unstable regions and correlated to the converted regions of magnetic to kinetic energies of the jets. We also found that an over-pressured relativistic jet leads to the generation of a series of stationary recollimation shocks and rarefaction structures by the nonlinear interaction of shocks and rarefaction waves. The differences in the recollimation shock structure due to the difference of the magnetic field topologies and strengths may be observable through mm-VLBI observations and space-VLBI mission.

  15. Ethylene: Role in Fruit Abscission and Dehiscence Processes 12

    Science.gov (United States)

    Lipe, John A.; Morgan, Page W.

    1972-01-01

    Two peaks of ethylene production occur during the development of cotton fruitz (Gossypium hirsutum L.). These periods precede the occurrence of young fruit shedding and mature fruit dehiscence, both of which are abscission phenomena and the latter is generally assumed to be part of the total ripening process. Detailed study of the dehiscence process revealed that ethylene production of individual, attached cotton fruits goes through a rising, cyclic pattern which reaches a maximum prior to dehiscence. With detached pecan fruits (Carya illinoensis [Wang.] K. Koch), ethylene production measured on alternate days rose above 1 microliter per kilogram fresh weight per hour before dehiscence began and reached a peak several days prior to complete dehiscence. Ethylene production by cotton and pecan fruits was measured just prior to dehiscence and then the internal concentration of the gas near the center of the fruit was determined. From these data a ratio of production rate to internal concentration was determined which allowed calculation of the approximate ethylene concentration in the intact fruit prior to dehiscence and selection of appropriate levels to apply to fruits. Ethylene at 10 microliters per liter of air appears to saturate dehiscence of cotton, pecan, and okra (Hibiscus esculentus L.) fruits and the process is completed in 3 to 4 days. In all cases some hastening of dehiscence was observed with as little as 0.1 microliter of exogenous ethylene per liter of air. The time required for response to different levels of ethylene was determined and compared to the time course of ethylene production and dehiscence. We concluded that internal levels of ethylene rose to dehiscence-stimulating levels a sufficience time before dehiscence for the gas to have initiated the process. Since our data and calculations indicate that enough ethylene is made a sufficient time before dehiscence, to account for the process, we propose that ethylene is one of the regulators of

  16. Ethylene: role in fruit abscission and dehiscence processes.

    Science.gov (United States)

    Lipe, J A; Morgan, P W

    1972-12-01

    Two peaks of ethylene production occur during the development of cotton fruitz (Gossypium hirsutum L.). These periods precede the occurrence of young fruit shedding and mature fruit dehiscence, both of which are abscission phenomena and the latter is generally assumed to be part of the total ripening process. Detailed study of the dehiscence process revealed that ethylene production of individual, attached cotton fruits goes through a rising, cyclic pattern which reaches a maximum prior to dehiscence. With detached pecan fruits (Carya illinoensis [Wang.] K. Koch), ethylene production measured on alternate days rose above 1 microliter per kilogram fresh weight per hour before dehiscence began and reached a peak several days prior to complete dehiscence. Ethylene production by cotton and pecan fruits was measured just prior to dehiscence and then the internal concentration of the gas near the center of the fruit was determined. From these data a ratio of production rate to internal concentration was determined which allowed calculation of the approximate ethylene concentration in the intact fruit prior to dehiscence and selection of appropriate levels to apply to fruits. Ethylene at 10 microliters per liter of air appears to saturate dehiscence of cotton, pecan, and okra (Hibiscus esculentus L.) fruits and the process is completed in 3 to 4 days. In all cases some hastening of dehiscence was observed with as little as 0.1 microliter of exogenous ethylene per liter of air. The time required for response to different levels of ethylene was determined and compared to the time course of ethylene production and dehiscence. We concluded that internal levels of ethylene rose to dehiscence-stimulating levels a sufficience time before dehiscence for the gas to have initiated the process. Since our data and calculations indicate that enough ethylene is made a sufficient time before dehiscence, to account for the process, we propose that ethylene is one of the regulators of

  17. Radicidation as an alternative for ethylene oxide

    Energy Technology Data Exchange (ETDEWEB)

    Farkas, J. (Koezponti Elelmiszeripari Kutato Intezet, Budapest (Hungary))

    1985-01-01

    The application of ethylene oxide to sterilize dry foodstuff additions proved to be a source of danger both for the personnel of the food preservation industry and for the consumers due to the residue of some chemicals and toxic reaction products which can not be removed from the foodstuff. A more advantageous and less harmful alternative for the reduction of the number of germs is offered by using ionizing radiation. Based on a great number of references, the applicability and effectiveness of radicidation for the preservation of spices, dry vegetable powders, sugar, thickening materials, protein and enzyme products were confirmed. Regarding the economic aspects, this method can be compared with the traditional chemical treatment. Commercial licenses have been issued by the health organizations of 12 countries.

  18. CFD Simulation on Ethylene Furnace Reactor Tubes

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Different mathematical models for ethylene furnace reactor tubes were reviewed. On the basis of these models a new mathematical simulation approach for reactor tubes based on computational fluid dynamics (CFD) technique was presented. This approach took the flow, heat transfer, mass transfer and thermal cracking reactions in the reactor tubes into consideration. The coupled reactor model was solved with the SIMPLE algorithm. Some detailed information about the flow field, temperature field and concentration distribution in the reactor tubes was obtained, revealing the basic characteristics of the hydrodynamic phenomena and reaction behavior in the reactor tubes. The CFD approach provides the necessary information for conclusive decisions regarding the production optimization, the design and improvement of reactor tubes, and the new techniques implementation.

  19. Information theory and the ethylene genetic network.

    Science.gov (United States)

    González-García, José S; Díaz, José

    2011-10-01

    information content in the input message that the cell's genetic machinery is processing during a given time interval. Furthermore, combining Information Theory with the frequency response analysis of dynamical systems we can examine the cell's genetic response to input signals with varying frequencies, amplitude and form, in order to determine if the cell can distinguish between different regimes of information flow from the environment. In the particular case of the ethylene signaling pathway, the amount of information managed by the root cell of Arabidopsis can be correlated with the frequency of the input signal. The ethylene signaling pathway cuts off very low and very high frequencies, allowing a window of frequency response in which the nucleus reads the incoming message as a varying input. Outside of this window the nucleus reads the input message as an approximately non-varying one. This frequency response analysis is also useful to estimate the rate of information transfer during the transport of each new ERF1 molecule into the nucleus. Additionally, application of Information Theory to analysis of the flow of information in the ethylene signaling pathway provides a deeper insight in the form in which the transition between auxin and ethylene hormonal activity occurs during a circadian cycle. An ambitious goal for the future would be to use Information Theory as a theoretical foundation for a suitable model of the information flow that runs at each level and through all levels of biological organization.

  20. Production of ethanol from excess ethylene

    DEFF Research Database (Denmark)

    Kadhim, Adam S.; Carlsen, Kim B.; Bisgaard, Thomas

    2012-01-01

    will focus on the synthetic method, which employs direct hydration of ethylene. A conceptual process design of an ethyl alcohol producing plant is performed in a MSc-level course on Process Design at the Department of Chemical and Biochemical Engineering at DTU. In the designed process, 190 proof ethyl...... is obtained in tasks 1-2. A preliminary process flowsheet is obtained in task 3 using a modified Douglas hierarchical process synthesis method. The next tasks involves making design decisions and then further refining them in tasks 4-7 related to separation factors, reactor operating conditions, product...... with respect to heat integration and process optimization (tasks 10-11). In the final task-12, the environmental impact of the process design is evaluated together with some of the key sustainability measures. In addition to PRO/II, the following software is used: ICAS (for property prediction, analysis...

  1. Bacterial Modulation of Plant Ethylene Levels.

    Science.gov (United States)

    Gamalero, Elisa; Glick, Bernard R

    2015-09-01

    A focus on the mechanisms by which ACC deaminase-containing bacteria facilitate plant growth.Bacteria that produce the enzyme 1-aminocyclopropane-1-carboxylate (ACC) deaminase, when present either on the surface of plant roots (rhizospheric) or within plant tissues (endophytic), play an active role in modulating ethylene levels in plants. This enzyme activity facilitates plant growth especially in the presence of various environmental stresses. Thus, plant growth-promoting bacteria that express ACC deaminase activity protect plants from growth inhibition by flooding and anoxia, drought, high salt, the presence of fungal and bacterial pathogens, nematodes, and the presence of metals and organic contaminants. Bacteria that express ACC deaminase activity also decrease the rate of flower wilting, promote the rooting of cuttings, and facilitate the nodulation of legumes. Here, the mechanisms behind bacterial ACC deaminase facilitation of plant growth and development are discussed, and numerous examples of the use of bacteria with this activity are summarized.

  2. Plants having modified response to ethylene

    Science.gov (United States)

    Meyerowitz, E.M.; Chang, C.; Bleecker, A.B.

    1997-11-18

    The invention includes transformed plants having at least one cell transformed with a modified ETR nucleic acid. Such plants have a phenotype characterized by a decrease in the response of at least one transformed plant cell to ethylene as compared to a plant not containing the transformed plant cell. Tissue and/or temporal specificity for expression of the modified ETR nucleic acid is controlled by selecting appropriate expression regulation sequences to target the location and/or time of expression of the transformed nucleic acid. The plants are made by transforming at least one plant cell with an appropriate modified ETR nucleic acid, regenerating plants from one or more of the transformed plant cells and selecting at least one plant having the desired phenotype. 31 figs.

  3. Production of ethanol from excess ethylene

    DEFF Research Database (Denmark)

    Kadhim, Adam S.; Carlsen, Kim B.; Bisgaard, Thomas

    2012-01-01

    ) and ECON (cost and economic analysis). This design therefore covers all stages of conceptual design, starting from the consideration of qualitative aspects of the process flowsheet and preliminary calculations to detailed process simulations, equipment sizing, costing and an economic evaluation......Ethyl alcohol is one of the most important and used chemicals. Two common routes exist for the production: synthetic route typically based on petroleum feedstock and a fermentation route. The fermentation route comprises the majority of the produced ethyl alcohol. In this work, however, we...... will focus on the synthetic method, which employs direct hydration of ethylene. A conceptual process design of an ethyl alcohol producing plant is performed in a MSc-level course on Process Design at the Department of Chemical and Biochemical Engineering at DTU. In the designed process, 190 proof ethyl...

  4. Photothermal degradation of ethylene/vinylacetate copolymer

    Science.gov (United States)

    Liang, R. H.; Chung, S.; Clayton, A.; Di Stefano, S.; Oda, K.; Hong, S. D.; Gupta, A.

    1983-01-01

    Photothermal degradation studies were conducted on a 'stabilized' formulation of ethylene/vinyl acetate copolymer (EVA) in the temperature range 25-105 C under three different oxygen environments (in open air, with limited access to O2, and in a dark closed stagnant oven). These studies were performed in order to evaluate the utility of EVA as an encapsulation material for photovoltaic modules. Results showed that at low temperature (25 C), slow photooxidation of the polymer occurred via electronic energy transfer involving the UV absorber incorporated in the polymer. However, no changes in the physical properties of the bulk polymer were detected up to 1500 hours of irradiation. At elevated temperatures, leaching and evaporation of the additives occurred, which ultimately resulted in the chemical crosslinking of the copolymer and the formation of volatile photoproducts such as acetic acid.

  5. Information theory and the ethylene genetic network

    Science.gov (United States)

    González-García, José S

    2011-01-01

    information content in the input message that the cell's genetic machinery is processing during a given time interval. Furthermore, combining Information Theory with the frequency response analysis of dynamical systems we can examine the cell's genetic response to input signals with varying frequencies, amplitude and form, in order to determine if the cell can distinguish between different regimes of information flow from the environment. In the particular case of the ethylene signaling pathway, the amount of information managed by the root cell of Arabidopsis can be correlated with the frequency of the input signal. The ethylene signaling pathway cuts off very low and very high frequencies, allowing a window of frequency response in which the nucleus reads the incoming message as a varying input. Outside of this window the nucleus reads the input message as an approximately non-varying one. This frequency response analysis is also useful to estimate the rate of information transfer during the transport of each new ERF1 molecule into the nucleus. Additionally, application of Information Theory to analysis of the flow of information in the ethylene signaling pathway provides a deeper insight in the form in which the transition between auxin and ethylene hormonal activity occurs during a circadian cycle. An ambitious goal for the future would be to use Information Theory as a theoretical foundation for a suitable model of the information flow that runs at each level and through all levels of biological organization. PMID:21897127

  6. Jet energy calibration in ATLAS

    CERN Document Server

    Schouten, Doug

    A correct energy calibration for jets is essential to the success of the ATLAS experi- ment. In this thesis I study a method for deriving an in situ jet energy calibration for the ATLAS detector. In particular, I show the applicability of the missing transverse energy projection fraction method. This method is shown to set the correct mean energy for jets. Pileup effects due to the high luminosities at ATLAS are also stud- ied. I study the correlations in lateral distributions of pileup energy, as well as the luminosity dependence of the in situ calibration metho

  7. Jet performance in Run 2 at ATLAS

    CERN Document Server

    Kunigo, Takuto; The ATLAS collaboration

    2016-01-01

    Slides for the talk "Jet performance in Run 2" at BOOST 2016. In this talk, the jet energy calibration sequence ( including in-situ calibrations at $\\sqrt{s} = 13$ TeV ), jet energy scale and resolution uncertainties and the jet calibration plan for 2016 will be presented.

  8. Ink-jet printed porous composite LiFePO4 electrode from aqueous suspension for microbatteries

    Science.gov (United States)

    Delannoy, P.-E.; Riou, B.; Brousse, T.; Le Bideau, J.; Guyomard, D.; Lestriez, B.

    2015-08-01

    This work demonstrates ink-jet printed LiFePO4-based composite porous electrodes for microbattery application. As binder and dispersant, we found that aqueous inks with more suitable rheological properties with respect to ink-jet printing are prepared with the low molecular weight poly-acrylic-co-maleic acid copolymer, rather than with the carboxymethyl cellulose standard binder of the lithium-ion technology. The ink-jet printed thin and porous electrode shows very high rate charge/discharge behavior, both in LiPF6/ethylene carbonate-dimethyl carbonate (LP30) and lithium bis(trifluoromethane)sulfonylimide salt (Li-TFSI) in N-methyl-N-propylpyrrolidinium bis(trifluoromethane)suflonylimide ionic liquid (PYR13-TFSI) electrolytes, as well as good cyclability.

  9. Jet reconstruction and heavy jet tagging at LHCb

    CERN Document Server

    CERN. Geneva

    2017-01-01

    The jet reconstruction and the heavy jet flavour tagging at LHCb will be discussed with focus on the last published measurements such as the measurement of forward tt, W+bb and W+cc production in pp collisions at √s=8 TeV and the search for the SM Higgs boson decaying in bbbar or ccbar in association to W or Z boson.

  10. Occupational exposure to ethylene oxide and risk of lymphoma.

    Science.gov (United States)

    Kiran, Sibel; Cocco, Pierluigi; Mannetje, Andrea't; Satta, Giannina; D'Andrea, Ileana; Becker, Nikolaus; de Sanjosé, Silvia; Foretova, Lenka; Staines, Anthony; Kleefeld, Silke; Maynadié, Marc; Nieters, Alexandra; Brennan, Paul; Boffetta, Paolo

    2010-11-01

    Ethylene oxide, a high-volume commodity, is an established human carcinogen, although the relevant epidemiologic evidence is limited. We explored the association between occupational exposure to ethylene oxide and risk of lymphoma in a case-control study, including 2347 lymphoma cases first diagnosed in 1998-2004 and 2463 controls, from 6 European countries. The diagnosis of lymphoma was based on the 2001 World Health Organization Classification of lymphoma. Occupational exposure to ethylene oxide was retrospectively assessed by industrial hygienists and occupational physicians based on detailed self-reported information. We modeled risk of lymphoma with unconditional logistic regression analysis as a function of various exposure measures, adjusting for age, sex, and participating center. Thirty-one cases and 27 controls (1.2% of the total study population) were defined as ever having been exposed to ethylene oxide (odds ratio = 1.3 [95% confidence interval [CI] = 0.7-2.1]). Lymphoma risk showed a 4.3-fold increase associated with medium-high frequency of exposure to ethylene oxide (95% CI = 1.4-13). Among major subtypes, chronic lymphocytic leukemia was consistently associated with ethylene oxide exposure, related in a dose-response manner to probability, frequency, and duration of exposure, as well as to cumulative exposure and (less definitively) with exposure intensity. Our results add to the evidence that ethylene oxide is a human carcinogen.

  11. Ethylene Signaling Influences Light-Regulated Development in Pea.

    Science.gov (United States)

    Weller, James L; Foo, Eloise M; Hecht, Valérie; Ridge, Stephen; Vander Schoor, Jacqueline K; Reid, James B

    2015-09-01

    Plant responses to light involve a complex network of interactions among multiple plant hormones. In a screen for mutants showing altered photomorphogenesis under red light, we identified a mutant with dramatically enhanced leaf expansion and delayed petal senescence. We show that this mutant exhibits reduced sensitivity to ethylene and carries a nonsense mutation in the single pea (Pisum sativum) ortholog of the ethylene signaling gene ETHYLENE INSENSITIVE2 (EIN2). Consistent with this observation, the ein2 mutation rescues the previously described effects of ethylene overproduction in mature phytochrome-deficient plants. In seedlings, ein2 confers a marked increase in leaf expansion under monochromatic red, far-red, or blue light, and interaction with phytochromeA, phytochromeB, and long1 mutants confirms that ein2 enhances both phytochrome- and cryptochrome-dependent responses in a LONG1-dependent manner. In contrast, minimal effects of ein2 on seedling development in darkness or high-irradiance white light show that ethylene is not limiting for development under these conditions. These results indicate that ethylene signaling constrains leaf expansion during deetiolation in pea and provide further evidence that down-regulation of ethylene production may be an important component mechanism in the broader control of photomorphogenic development by phytochrome and cryptochrome.

  12. Ethylene oxide removal by sorption on aluminium oxide

    Directory of Open Access Journals (Sweden)

    Arsenijević Zorana Lj.

    2009-01-01

    Full Text Available The dynamics of ethylene oxide sorption and desorption on Al2O3 sorbent were investigated. The investigations of ethylene oxide sorption on Al2O3 show that significant sorption appeared above 125°C. The removal of sorbed ethylene oxide from Al2O3 was achieved by continuous increasing of the temperature up to 450°C in air stream. The analysis of desorbed products show that 90% of adsorbed ethylene oxide is converted to CO2 and the rest consists of the three derivatives of ethylene oxide. The exact composition of desorbed organic products will be determined in further investigation. The desorption temperature profiles point out the presence of two exothermic picks, as was confirmed by detection of CO2 and derivates of ethylene oxide at these temperatures. Investigation of textural characteristics and thermal stability of Al2O3 sorbent show that there are no changes of any characteristics of Al2O3 in sorption/desorption operating temperatures regimes. Only at 700°C the specific surface area of Al2O3 decreases of about 10%. This indicates that the investigated Al2O3 is convenient material for removal of ethylene oxide by sorption.

  13. Localization of the Ethylene-synthesizing System in Apple Tissue.

    Science.gov (United States)

    Mattoo, A K; Lieberman, M

    1977-11-01

    Apple (Malus sp.) slices gradually lost the ability to synthesize ethylene when incubated with a mixture of enzymes that digest cell walls. The released protoplasts did not produce ethylene. The release of protoplasts was faster from climacteric fruit slices than from preclimacteric tissue. In protoplast suspension culture, as new cell wall was deposited (as judged by the intensity of fluorescence of regenerating protoplasts stained with Calcofluor White and the incorporation of labeled myo-inositol into their ethanol-insoluble residue), ethylene synthesis was gradually regained. Restored ethylene synthesis reached a maximum after 80 hours in protoplasts from preclimacteric fruit and in 120 hours in those from climacteric tissue. Addition of methionine (1 mm) to the culture medium was essential for appreciable synthesis of ethylene; and this synthesis was inhibited by the aminoethoxy analogue of rhizobitoxine and by propyl gallate, inhibitors of ethylene synthesis in higher plants. We suggest that the ethylene-synthesizing enzyme system is highly structured in the apple cell and is localized in a cell wall-cell membrane complex.

  14. Jet charge determination at the LHC

    CERN Document Server

    Tokar, Stano; The ATLAS collaboration

    2017-01-01

    Knowing the charge of the parton initiating a jet could be very useful both for testing different aspects of the Standard model and for searching signals of a beyond-the-standard-model physics. A weighted sum of the charges of a jet constituents can be used at the LHC experiments to distinguish among jets from partons with different charges. A few applications of the jet charge variable are presented here. The jet charge was used to distinguish jets initiated by $b$ quarks from those initiated by $\\bar{b}$ quarks, for distinguishing between boosted hadronically decaying $W^+$ and $W^{-}$, and for distinguishing jets initiated by quarks from those initiated by gluons.

  15. Needle-free jet injections: dependence of jet penetration and dispersion in the skin on jet power.

    Science.gov (United States)

    Schramm-Baxter, Joy; Mitragotri, Samir

    2004-07-07

    Jet injection is a needle-free drug delivery method in which a high-speed stream of fluid impacts the skin and delivers drugs. Although a number of jet injectors are commercially available, especially for insulin delivery, a quantitative understanding of the energetics of jet injection is still lacking. Here, we describe the dependence of jet injections into human skin on the power of the jet. Dermal delivery of liquid jets was quantified using two measurements, penetration of a radiolabeled solute, mannitol, into skin and the shape of jet dispersion in the skin which was visualized using sulforhodamine B (SRB). The power of the jet at the nozzle was varied from 1 to 600 W by independently altering the nozzle diameter (30-560 microm) and jet velocity (100-200 m/s). The dependence of the amount of liquid delivered in the skin and the geometric measurements of jet dispersion on nozzle diameter and jet velocity was captured by a single parameter, jet power. Additional experiments were performed using a model material, polyacrylamide gel, to further understand the dependence of jet penetration on jet power. These experiments demonstrated that jet power also effectively describes gel erosion due to liquid impingement.

  16. Evolution variable dependence of jet substructure

    CERN Document Server

    Sakaki, Yasuhito

    2015-01-01

    Studies on jet substructure have evolved significantly in recent years. Jet substructure is essentially determined by QCD radiations and non-perturbative effects. Predictions of jet substructure are usually different among Monte Carlo event generators, and are governed by the parton shower algorithm implemented. For leading logarithmic parton shower, even though one of the core variables is the evolution variable, its choice is not unique. We examine evolution variable dependence of the jet substructure by developing a parton shower generator that interpolates between different evolution variables using a parameter $\\alpha$. Jet shape variables and associated jet rates for quark and gluon jets are used to demonstrate the $\\alpha$-dependence of the jet substructure. We find angular ordered shower predicts wider jets, while relative transverse momentum ($p_{\\bot}$) ordered shower predicts narrower jets. This is qualitatively in agreement with the missing phase space of $p_{\\bot}$ ordered showers. Such differenc...

  17. Shedding light on ethylene metabolism in higher plants

    Directory of Open Access Journals (Sweden)

    Maria Aurineide Rodrigues

    2014-12-01

    Full Text Available Ethylene metabolism in higher plants is regulated by a wide array of endogenous and environmental factors. During most physiological processes, ethylene levels are mainly determined by a strict control of the rate-limiting biosynthetic steps responsible for the production of 1-aminocyclopropane-1-carboxylic acid (ACC and its subsequent conversion to ethylene. Responsible for these reactions, the key enzymes ACC synthase and ACC oxidase are encoded by multigene families formed by members that can be differentially regulated at the transcription and post-translational levels by specific developmental and environmental signals. Among the wide variety of environmental cues controlling plant ethylene production, light quality, duration and intensity have consistently been demonstrated to influence the metabolism of this plant hormone in diverse plant tissues, organs and species. Although still not completely elucidated, the mechanisms underlying the interaction between light signal transduction and ethylene evolution appears to involve a complex network that includes central transcription factors connecting multiple signaling pathways, which can be reciprocally modulated by ethylene itself, other phytohormones, and specific light wavelengths. Accumulating evidence has indicated particular photoreceptors as essential mediators in light-induced signaling cascades affecting ethylene levels. Therefore, this review specifically focuses on discussing the current knowledge of the potential molecular mechanisms implicated in the light-induced responses affecting ethylene metabolism during the regulation of developmental and metabolic plant responses. Besides presenting the state of the art in this research field, some overlooked mechanisms and future directions to elucidate the exact nature of the light-ethylene interplay in higher plants will also be compiled and discussed.

  18. Turbulent structure and emissions of strongly-pulsed jet diffusion flames

    Science.gov (United States)

    Fregeau, Mathieu

    This current research project studied the turbulent flame structure, the fuel/air mixing, the combustion characteristics of a nonpremixed pulsed (unsteady) and unpulsed (steady) flame configuration for both normal- and microgravity conditions, as well as the flame emissions in normal gravity. The unsteady flames were fully-modulated, with the fuel flow completely shut off between injection pulses using an externally controlled valve, resulting in the generation of compact puff-like flame structures. Conducting experiments in normal and microgravity environments enabled separate control over the relevant Richardson and Reynolds numbers to clarify the influence of buoyancy on the flame behavior, mixing, and structure. Experiments were performed in normal gravity in the laboratory at the University of Washington and in microgravity using the NASA GRC 2.2-second Drop Tower facility. High-speed imaging, as well as temperature and emissions probes were used to determine the large-scale structure dynamics, the details of the flame structure and oxidizer entrainment, the combustion temperatures, and the exhaust emissions of the pulsed and steady flames. Of particular interest was the impact of changes in flame structure due to pulsing on the combustion characteristics of this system. The turbulent flame puff celerity (i.e., the bulk velocity of the puffs) was strongly impacted by the jet-off time, increasing markedly as the time between pulses was decreased, which caused the degree of puff interaction to increase and the strongly-pulsed flame to more closely resemble a steady flame. This increase occurred for all values of injection time as well as for constant fuelling rate and in both the presence and absence of buoyancy. The removal of positive buoyancy in microgravity resulted in a decrease in the flame puff celerity in all cases, amounting to as much as 40%, for both constant jet injection velocity and constant fuelling rate. The mean flame length of the strongly

  19. The molecular basis of ethylene signalling in Arabidopsis

    Science.gov (United States)

    Woeste, K.; Kieber, J. J.; Evans, M. L. (Principal Investigator)

    1998-01-01

    The simple gas ethylene profoundly influences plants at nearly every stage of growth and development. In the past ten years, the use of a genetic approach, based on the triple response phenotype, has been a powerful tool for investigating the molecular events that underlie these effects. Several fundamental elements of the pathway have been described: a receptor with homology to bacterial two-component histidine kinases (ETR1), elements of a MAP kinase cascade (CTR1) and a putative transcription factor (EIN3). Taken together, these elements can be assembled into a simple, linear model for ethylene signalling that accounts for most of the well-characterized ethylene mediated responses.

  20. V+jets from CMS

    CERN Document Server

    Zhang, Fengwangdong

    2016-01-01

    This document is dedicated to recent results on the measurements of a vector boson production associated with jets (V+jets) using CMS detector experiment, with a central proton-proton (pp) collision energy of respectively 8 TeV (RunI) and 13 TeV (RunII). The vector boson can be a W boson, Z boson, or photon. The jets are of any flavor, as well as the ones containing heavy flavor quarks, such as bottom(b) quarks. The inclusive cross sections of V+jets processes and differential cross sections as a function of various kinematic observables are presented and compared to several theoretical predictions. In general, the comparison between theoretical calculations and measurement are crucial for improving modeling and precision on QCD dynamics.

  1. Top Jets at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, L.G.; Lee, S.J.; Perez, G.; Sung, I.; Virzi, J.

    2008-10-06

    We investigatethe reconstruction of high pT hadronically-decaying top quarksat the Large Hadron Collider. One of the main challenges in identifying energetictop quarks is that the decay products become increasingly collimated. This reducesthe efficacy of conventional reconstruction methods that exploit the topology of thetop quark decay chain. We focus on the cases where the decay products of the topquark are reconstructed as a single jet, a"top-jet." The most basic"top-tag" methodbased on jet mass measurement is considered in detail. To analyze the feasibility ofthe top-tagging method, both theoretical and experimental aspects of the large QCDjet background contribution are examined. Based on a factorization approach, wederive a simple analytic approximation for the shape of the QCD jet mass spectrum.We observe very good agreement with the Monte Carlo simulation. We consider high pT tt bar production in the Standard Model as an example, and show that our theoretical QCD jet mass distributions can efficiently characterize the background via sideband analyses. We show that with 25 fb-1 of data, our approach allows us to resolve top-jets with pT _> 1 TeV, from the QCD background, and about 1.5 TeV top-jets with 100 fb-1, without relying on b-tagging. To further improve the significancewe consider jet shapes (recently analyzed in 0807.0234 [hep-ph]), which resolve thesubstructure of energy flow inside cone jets. A method of measuring the top quarkpolarization by using the transverse momentum of the bottom quark is also presented.The main advantages of our approach are: (i) the mass distributions are driven byfirst principle calculations, instead of relying solely on Monte Carlo simulation; (ii) for high pT jets (pT _> 1 TeV), IR-safe jet shape variables are robust against detectorresolution effects. Our analysis can be applied to other boosted massive particlessuch as the electroweak gauge bosons and the Higgs.

  2. Membrane-based gas separation of ethylene/ethylene oxide mixtures for product enrichment in microreactor technology.

    Science.gov (United States)

    Schiewe, B; Staudt-Bickel, C; Vuin, A; Wegner, G

    2001-04-17

    For the off-gas product separation in an ethylene oxide microreactor, new concepts need to be developed. Instead of using the technical process of low-temperature distillation, the performance of gas separation through a dense polymeric membrane was investigated. Different noncrosslinked and crosslinked 6FDA-based polyimides and copolyimides (6FDA=4,4'-hexafluoroisopropylidene diphthalic anhydride) were screened as potential membrane materials. The polymer structure of the membrane material was found to influence the solubility of ethylene oxide and ethylene. The introduction of polar substituents in the polymer backbone increases the solubility selectivity drastically. For permeation experiments in the same pressure range, a novel setup was developed using microstructured membrane supports. With this device, different polymer membranes were tested with respect to the pure gas permeability of ethylene oxide and ethylene as a function of the feed pressure, so that plasticisation effects could be discussed. For different polyimides and copolyimides, ideal ethylene oxide/ethylene selectivities between 3 and 4.5 were found combined with permeabilities between 1.8 and 80.8 barrer.

  3. Jet Quenching with Parton evolution

    CERN Document Server

    Cheng, Luan

    2009-01-01

    We report the evolution effects on jet energy loss with detailed balance. The initial conditions and parton evolution based on perturbative QCD in the chemical non-equilibrated medium and Bjorken expanding medium at RHIC are determined. The parton evolution affect the jet energy loss evidently. This will increase the energy and propagating distance dependence of the parton energy loss and will affect the shape of suppression of moderately high P_{T} hadron spectra.

  4. Jet-quenching and correlations

    Indian Academy of Sciences (India)

    Fuqiang Wang

    2015-05-01

    This article reviews recent advances in our understanding of the experimental aspects of jet-quenching and correlations in relativistic heavy-ion collisions at RHIC and LHC. Emphasis is put on correlation measurements, namely jet-like correlations with anisotropic flow subtraction in heavy-ion collisions and long-range pseudorapidity correlations in small systems. Future path on correlation studies is envisioned which may elucidate jet–medium interactions and the properties of the hot dense medium in QCD.

  5. Jets and environment of microquasars

    CERN Document Server

    Zhang, Shuang-Nan

    2008-01-01

    Two relativistic X-ray jets have been detected with the Chandra X-ray observatory from the black hole X-ray transient XTE J1550-564. We report a full analysis of the evolution of the two jets with a gamma-ray burst external shock model. A plausible scenario suggests a cavity outside the central source and the jets first travelled with constant velocity and then are slowed down by the interactions between the jets and the interstellar medium (ISM). The best fitted radius of the cavity is $\\sim$0.36 pc on the eastern side and $\\sim$0.46 pc on the western side, and the densities also show asymmetry, of $\\sim$0.015 cm$^{-3}$ on the east to $\\sim$0.21 cm$^{-3}$ on the west. A large scale low density region is also found in another microquasar system, H 1743-322. These results are consistent with previous suggestions that the environment of microquasars should be rather vacuous, compared to the normal Galactic environment. A generic scenario for microquasar jets is proposed, classifying the observed jets into three...

  6. Numerical Simulations of Bouncing Jets

    CERN Document Server

    Bonito, Andrea; Lee, Sanghyun

    2015-01-01

    Bouncing jets are fascinating phenomenons occurring under certain conditions when a jet impinges on a free surface. This effect is observed when the fluid is Newtonian and the jet falls in a bath undergoing a solid motion. It occurs also for non-Newtonian fluids when the jets falls in a vessel at rest containing the same fluid. We investigate numerically the impact of the experimental setting and the rheological properties of the fluid on the onset of the bouncing phenomenon. Our investigations show that the occurrence of a thin lubricating layer of air separating the jet and the rest of the liquid is a key factor for the bouncing of the jet to happen. The numerical technique that is used consists of a projection method for the Navier-Stokes system coupled with a level set formulation for the representation of the interface. The space approximation is done with adaptive finite elements. Adaptive refinement is shown to be very important to capture the thin layer of air that is responsible for the bouncing.

  7. [Liver resection by water jet].

    Science.gov (United States)

    Horie, T

    1989-01-01

    Major problem in resecting liver parenchyma is how to control the bleeding. Recently, resection of the liver by water jet has been reported. So, experimental and clinical studies were performed to investigate the usefulness of the water jet equipment. Ten pigs weighing around 17kg were used. The optimal pressure to resect the porcine liver was 7 to 15kg/cm2. By 4 weeks the cut surface was covered with fibrous capsule. Portal angiography showed no abnormality in the resected area. The water jet was also used in 30 human operations. The optimal pressure was 12 to 18kg/cm2 for non cirrhotic liver and 15 to 20kg/cm2 for cirrhotic liver. The surface immediately after jet cutting was more smooth than that of CUSA and histologically there was slight bleeding and necrosis. The volume of blood loss during dissection was not different between water jet group and CUSA group. No significant changes were found in the laboratory data. These results suggest that water jet is as useful as CUSA for cutting the liver parenchyma.

  8. Relativistic AGN jets I. The delicate interplay between jet structure, cocoon morphology and jet-head propagation

    CERN Document Server

    Walg, S; Markoff, S; Keppens, R; Meliani, Z

    2013-01-01

    Current observations have shown that astrophysical jets reveal strong signs of radial structure. They suggest that the inner region of the jet, the jet spine, consists of a low-density, fast-moving gas, while the outer region of the jet consists of a more dense and slower moving gas, called the jet sheath. Moreover, if jets carry angular momentum, the resultant centrifugal forces lead to a radial stratification. Current observations are not able to fully resolve the radial structure, so little is known about its actual profile. We present three AGN jet models in $2.5D$ of which two have been given a radial structure. The first model is a homogeneous jet, the only model that doesn't carry angular momentum; the second model is a spine-sheath jet with an isothermal equation of state; and the third jet model is a (piecewise) isochoric spine-sheath jet, with constant but different densities for jet spine and jet sheath. In this paper, we look at the effects of radial stratification on jet integrity, mixing between...

  9. Identification of rice ethylene-response mutants and characterization of MHZ7/OsEIN2 in distinct ethylene response and yield trait regulation.

    Science.gov (United States)

    Ma, Biao; He, Si-Jie; Duan, Kai-Xuan; Yin, Cui-Cui; Chen, Hui; Yang, Chao; Xiong, Qing; Song, Qing-Xin; Lu, Xiang; Chen, Hao-Wei; Zhang, Wan-Ke; Lu, Tie-Gang; Chen, Shou-Yi; Zhang, Jin-Song

    2013-11-01

    Ethylene plays essential roles in adaptive growth of rice plants in water-saturating environment; however, ethylene signaling pathway in rice is largely unclear. In this study, we report identification and characterization of ethylene-response mutants based on the specific ethylene-response phenotypes of etiolated rice seedlings, including ethylene-inhibited root growth and ethylene-promoted coleoptile elongation, which is different from the ethylene triple-response phenotype in Arabidopsis. We establish an efficient system for screening and a set of rice mutants have been identified. Genetic analysis reveals that these mutants form eight complementation groups. All the mutants show insensitivity or reduced sensitivity to ethylene in root growth but exhibit differential responses in coleoptile growth. One mutant group mhz7 has insensitivity to ethylene in both root and coleoptile growth. We identified the corresponding gene by a map-based cloning method. MHZ7 encodes a membrane protein homologous to EIN2, a central component of ethylene signaling in Arabidopsis. Upon ethylene treatment, etiolated MHZ7-overexpressing seedlings exhibit enhanced coleoptile elongation, increased mesocotyl growth and extremely twisted short roots, featuring enhanced ethylene-response phenotypes in rice. Grain length was promoted in MHZ7-transgenic plants and 1000-grain weight was reduced in mhz7 mutants. Leaf senescent process was also affected by MHZ7 expression. Manipulation of ethylene signaling may improve adaptive growth and yield-related traits in rice.

  10. From free jets to clinging wall jets: The influence of a horizontal boundary on a horizontally forced buoyant jet

    Science.gov (United States)

    Burridge, H. C.; Hunt, G. R.

    2017-02-01

    We investigate the incompressible turbulent jet formed when buoyant fluid is steadily ejected horizontally from a circular source into an otherwise quiescent uniform environment. As our primary focus, we introduce a horizontal boundary beneath the source. For sufficiently small separations, the jet attaches and clings to the boundary, herein the "clinging jet," before, farther downstream, the jet is pulled away from the boundary by the buoyancy force. For larger source-boundary separations, the buoyant jet is free to rise under the action of the buoyancy force, herein the "free jet." Based on measurements of saline jets in freshwater surroundings we deduce the conditions required for a jet to cling. We present a data set that spans a broad range of source conditions for the variation in volume flux (indicative of entrainment), jet perimeter, and jet centerline for both "clinging" and "free" jets. For source Froude numbers Fr0≥12 the data collapse when scaled, displaying universal behaviors for both clinging and free jets. Our results for the variation in the volume flux across horizontal planes, π Qjet , show that within a few jet lengths of the source, π Qjet for the clinging jet exceeds that of a free jet with identical source conditions. However, when examined in a coordinate following the jet centerline π Qjet for free jets is greater. Finally, we propose a new parametrization for an existing integral model which agrees well with our experimental data as well as with data from other studies. Our findings offer the potential to tailor the dilution of horizontal buoyant jets by altering the distance at which they are released from a boundary.

  11. Ethylene decomposition at undercoordinated sites on Cu(410).

    Science.gov (United States)

    Kravchuk, Tatyana; Vattuone, Luca; Burkholder, Luke; Tysoe, Wilfred T; Rocca, Mario

    2008-09-24

    We demonstrate the selective, low-temperature chemistry of ethylene on the strongly undercoordinated sites of Cu(410) by investigating its adsorption by high-resolution electron energy loss spectroscopy (HREELS), X-ray photoelectron spectroscopy (XPS), and temperature-programmed desorption (TPD). After dosing ethylene at approximately 110 K, apart from the expected pi-bonded species adsorbed on terraces, di-sigma-bonded ethylene and carbon are formed at the step edges. The latter product results from the complete dehydrogenation of ethylene and blocks sites for further dissociation and/or di-sigma-adsorption. However, these processes can be restored merely by heating the sample to 900 K, by causing the carbon to diffuse into the bulk. The presented results support the relevance of copper-based catalysts for the steam reforming process.

  12. USE OF THERAPEUTIC PLASMAPHERESIS IN ETHYLENE DIBRO MIDE INTOXICATION

    Directory of Open Access Journals (Sweden)

    Dolly

    2013-02-01

    Full Text Available ABSTRACT: In view of high incidence of mortality with Ethylen e dibromide poisoning, a retrospective study was conducted, with objectives t o compare demographic, toxicological & clinical outcome in patients treated conservatively and those who underwent therapeutic plasmapheresis

  13. Copolymerization Kinetics of Ethylene Oxide and Propylene Oxide

    Institute of Scientific and Technical Information of China (English)

    尹红; 陈志荣

    2002-01-01

    The copolymerization kinetics of ethylene oxide and propylene oxide in an atomizing-circulation reactorunder semi-continuous operation is studied which is of great importance for molecular designation. The kineticparameters are obtained by numerical optimization of the kinetic model.

  14. Ethylene binding to Au/Cu alloy nanoparticles

    Science.gov (United States)

    Gammage, Michael D.; Stauffer, Shannon; Henkelman, Graeme; Becker, Michael F.; Keto, John W.; Kovar, Desiderio

    2016-11-01

    Weak chemisorption of ethylene has been shown to be an important characteristic in the use of metals for the separation of ethylene from ethane. Previously, density functional theory (DFT) has been used to predict the binding energies of various metals and alloys, with Ag having the lowest chemisorption energy amongst the metals and alloys studied. Here Au/Cu alloys are investigated by a combination of DFT calculations and experimental measurements. It is inferred from experiments that the binding energy between a Au/Cu alloy and ethylene is lower than to either of the pure metals, and DFT calculations confirm that this is the case when Au segregates to the particle surface. Implications of this work suggest that it may be possible to further tune the binding energy with ethylene by compositional and morphological control of films produced from Au-surface segregated alloys.

  15. A natural frameshift mutation in Campanula EIL2 correlates with ethylene insensitivity in flowers

    DEFF Research Database (Denmark)

    Jensen, Line; Hegelund, Josefine Nymark; Olsen, Andreas

    2016-01-01

    BACKGROUND: The phytohormone ethylene plays a central role in development and senescence of climacteric flowers. In ornamental plant production, ethylene sensitive plants are usually protected against negative effects of ethylene by application of chemical inhibitors. In Campanula, flowers...... are sensitive to even minute concentrations of ethylene. RESULTS: Monitoring flower longevity in three Campanula species revealed C. portenschlagiana (Cp) as ethylene sensitive, C. formanekiana (Cf) with intermediate sensitivity and C. medium (Cm) as ethylene insensitive. We identified key elements in ethylene...

  16. Links Between Ethylene and Sulfur Nutrition—A Regulatory Interplay or Just Metabolite Association?

    OpenAIRE

    Wawrzynska, Anna; Moniuszko, Grzegorz; Sirko, Agnieszka

    2015-01-01

    Multiple reports demonstrate associations between ethylene and sulfur metabolisms, however the details of these links have not yet been fully characterized; the links might be at the metabolic and the regulatory levels. First, sulfur-containing metabolite, methionine, is a precursor of ethylene and is a rate limiting metabolite for ethylene synthesis; the methionine cycle contributes to both sulfur and ethylene metabolism. On the other hand, ethylene is involved in the complex response networ...

  17. Ethylene epoxidation catalyzed by chlorine-promoted silver oxide

    Energy Technology Data Exchange (ETDEWEB)

    Ozbek, M O; Onal, I [Chemical Engineering Department, Middle East Technical University, 06531, Ankara (Turkey); Van Santen, R A, E-mail: r.a.v.santen@tue.nl [Chemical Engineering and Chemistry Department, Eindhoven University of Technology, 5600 MB, Eindhoven (Netherlands)

    2011-10-12

    It is demonstrated that, on a silver oxide surface, direct formation of ethylene oxide (EO) through the reaction between gas phase ethylene and surface oxygen is possible. The direct reaction channel produces EO selectively without competing with acetaldehyde (AA) formation. The oxometallacycle (OMC) forms on an oxygen vacant surface and reduces EO selectivity. Cl adsorption removes these surface vacant sites and hence prevents the formation of the OMC intermediate.

  18. Ethylene Emission of Apples Treated with 1-Methylcyclopropene During Storage

    Directory of Open Access Journals (Sweden)

    Melnyk Oleksandr

    2014-09-01

    Full Text Available The effect of post-harvest application of 1-methylcyclopropene (1-MCP on ethylene emission in early-winter apple (cv. ‘Calville’, winter (‘Gloster’, ‘Golden Delicious’ and ‘Jonagold’, and late-winter cultivars (‘Granny Smith’, ‘Idared’ and ‘Reinette Simirenko’ w as investigated. The fruits were picked at a commercial harvest time and half of them were treated with 1-MCP (‘SmartFresh™’ 0.068 gm-3 for 24 h at 5 °C. Then both groups of apples were placed in a common storage at the temperature of 2 °C. The intensity of fruit ethylene emission (rate of ethylene production was measured and 1 -MCP inhibition index was calculated. During storage, activity of ethylene emission by control apples of ‘Calville’ and ‘Golden Delicious’ showed typical climacteric pattern, while the intensity of ethylene emission of apples of other cultivars only increased gradually. The change of ethylene activity of early-winter apple cv. ‘Calville’ and winter cv. ‘Jonagold’, both treated with 1-MCP after harvest, had exponential character, especially actively increasing after 3 months of storage. At the same time ethylene emission of 1 -MCP treated fruits of other cultivars changed steadily to a low level and was effectively suppressed during the whole 6-month period of storage in normal atmosphere. The value of inhibition index of fruits treated by 1-MCP confirmed the consistent restoration of the ability to ethylene synthesis and thus to post-harvest ripening of some apples cultivars.

  19. Quark and gluon jet properties in symmetric three-jet events

    CERN Document Server

    Buskulic, Damir; De Bonis, I; Décamp, D; Ghez, P; Goy, C; Lees, J P; Lucotte, A; Minard, M N; Odier, P; Pietrzyk, B; Chmeissani, M; Crespo, J M; Efthymiopoulos, I; Fernández, E; Fernández-Bosman, M; Garrido, L; Juste, A; Martínez, M; Orteu, S; Pacheco, A; Padilla, C; Palla, Fabrizio; Pascual, A; Perlas, J A; Riu, I; Sánchez, F; Teubert, F; Colaleo, A; Creanza, D; De Palma, M; Farilla, A; Gelao, G; Girone, M; Iaselli, Giuseppe; Maggi, G; Maggi, M; Marinelli, N; Natali, S; Nuzzo, S; Ranieri, A; Raso, G; Romano, F; Ruggieri, F; Selvaggi, G; Silvestris, L; Tempesta, P; Zito, G; Huang, X; Lin, J; Ouyang, Q; Wang, T; Xie, Y; Xu, R; Xue, S; Zhang, J; Zhang, L; Zhao, W; Alemany, R; Bazarko, A O; Bonvicini, G; Cattaneo, M; Comas, P; Coyle, P; Drevermann, H; Forty, Roger W; Frank, M; Hagelberg, R; Harvey, J; Jacobsen, R; Janot, P; Jost, B; Kneringer, E; Knobloch, J; Lehraus, Ivan; Martin, E B; Mato, P; Minten, Adolf G; Miquel, R; Mir, L M; Moneta, L; Oest, T; Palazzi, P; Pater, J R; Pusztaszeri, J F; Ranjard, F; Rensing, P E; Rolandi, Luigi; Schlatter, W D; Schmelling, M; Schneider, O; Tejessy, W; Tomalin, I R; Venturi, A; Wachsmuth, H W; Wildish, T; Witzeling, W; Wotschack, J; Ajaltouni, Ziad J; Barrès, A; Boyer, C; Falvard, A; Gay, P; Guicheney, C; Henrard, P; Jousset, J; Michel, B; Monteil, S; Montret, J C; Pallin, D; Perret, P; Podlyski, F; Proriol, J; Rossignol, J M; Fearnley, Tom; Hansen, J B; Hansen, J D; Hansen, J R; Hansen, P H; Nilsson, B S; Wäänänen, A; Kyriakis, A; Markou, C; Simopoulou, Errietta; Siotis, I; Vayaki, Anna; Zachariadou, K; Blondel, A; Bonneaud, G R; Brient, J C; Bourdon, P; Rougé, A; Rumpf, M; Tanaka, R; Valassi, Andrea; Verderi, M; Videau, H L; Candlin, D J; Parsons, M I; Focardi, E; Parrini, G; Corden, M; Delfino, M C; Georgiopoulos, C H; Jaffe, D E; Antonelli, A; Bencivenni, G; Bologna, G; Bossi, F; Campana, P; Capon, G; Chiarella, V; Felici, G; Laurelli, P; Mannocchi, G; Murtas, F; Murtas, G P; Passalacqua, L; Pepé-Altarelli, M; Curtis, L; Dorris, S J; Halley, A W; Knowles, I G; Lynch, J G; O'Shea, V; Raine, C; Reeves, P; Scarr, J M; Smith, K; Thompson, A S; Thomson, F; Thorn, S; Turnbull, R M; Becker, U; Braun, O; Geweniger, C; Graefe, G; Hanke, P; Hepp, V; Kluge, E E; Putzer, A; Rensch, B; Schmidt, M; Sommer, J; Stenzel, H; Tittel, K; Werner, S; Wunsch, M; Abbaneo, D; Beuselinck, R; Binnie, David M; Cameron, W; Colling, D J; Dornan, Peter J; Moutoussi, A; Nash, J; San Martin, G; Sedgbeer, J K; Stacey, A M; Dissertori, G; Girtler, P; Kuhn, D; Rudolph, G; Bowdery, C K; Brodbeck, T J; Colrain, P; Crawford, G; Finch, A J; Foster, F; Hughes, G; Sloan, Terence; Whelan, E P; Williams, M I; Galla, A; Greene, A M; Kleinknecht, K; Quast, G; Renk, B; Rohne, E; Sander, H G; Van Gemmeren, P; Zeitnitz, C; Aubert, Jean-Jacques; Bencheikh, A M; Benchouk, C; Bonissent, A; Bujosa, G; Calvet, D; Carr, J; Diaconu, C A; Etienne, F; Konstantinidis, N P; Nicod, D; Payre, P; Rousseau, D; Talby, M; Sadouki, A; Thulasidas, M; Trabelsi, K; Abt, I; Assmann, R W; Bauer, C; Blum, Walter; Brown, D; Dietl, H; Dydak, Friedrich; Ganis, G; Gotzhein, C; Jakobs, K; Kroha, H; Lütjens, G; Lutz, Gerhard; Männer, W; Moser, H G; Richter, R H; Rosado-Schlosser, A; Schael, S; Settles, Ronald; Seywerd, H C J; Saint-Denis, R; Wiedenmann, W; Wolf, G; Boucrot, J; Callot, O; Cordier, A; Davier, M; Duflot, L; Grivaz, J F; Heusse, P; Jacquet, M; Kim, D W; Le Diberder, F R; Lefrançois, J; Lutz, A M; Nikolic, I A; Park, H J; Park, I C; Schune, M H; Simion, S; Veillet, J J; Videau, I; Azzurri, P; Bagliesi, G; Batignani, G; Bettarini, S; Bozzi, C; Calderini, G; Carpinelli, M; Ciocci, M A; Ciulli, V; Dell'Orso, R; Fantechi, R; Ferrante, I; Foà, L; Forti, F; Giassi, A; Giorgi, M A; Gregorio, A; Ligabue, F; Lusiani, A; Marrocchesi, P S; Messineo, A; Rizzo, G; Sanguinetti, G; Sciabà, A; Spagnolo, P; Steinberger, Jack; Tenchini, Roberto; Tonelli, G; Vannini, C; Verdini, P G; Walsh, J; Betteridge, A P; Blair, G A; Bryant, L M; Cerutti, F; Chambers, J T; Gao, Y; Green, M G; Johnson, D L; Medcalf, T; Perrodo, P; Strong, J A; Von Wimmersperg-Töller, J H; Botterill, David R; Clifft, R W; Edgecock, T R; Haywood, S; Edwards, M; Maley, P; Norton, P R; Thompson, J C; Bloch-Devaux, B; Colas, P; Emery, S; Kozanecki, Witold; Lançon, E; Lemaire, M C; Locci, E; Marx, B; Pérez, P; Rander, J; Renardy, J F; Roussarie, A; Schuller, J P; Schwindling, J; Trabelsi, A; Vallage, B; Johnson, R P; Kim, H Y; Litke, A M; McNeil, M A; Taylor, G; Beddall, A; Booth, C N; Boswell, R; Brew, C A J; Cartwright, S L; Combley, F; Köksal, A; Letho, M; Newton, W M; Rankin, C; Reeve, J; Thompson, L F; Böhrer, A; Brandt, S; Cowan, G D; Feigl, E; Grupen, Claus; Lutters, G; Minguet-Rodríguez, J A; Rivera, F; Saraiva, P; Smolik, L; Stephan, F; Apollonio, M; Bosisio, L; Della Marina, R; Giannini, G; Gobbo, B; Musolino, G; Ragusa, F; Rothberg, J E; Wasserbaech, S R; Armstrong, S R; Bellantoni, L; Elmer, P; Feng, Z; Ferguson, D P S; Gao, Y S; González, S; Grahl, J; Greening, T C; Harton, J L; Hayes, O J; Hu, H; McNamara, P A; Nachtman, J M; Orejudos, W; Pan, Y B; Saadi, Y; Schmitt, M; Scott, I J; Sharma, V; Turk, J; Walsh, A M; Wu Sau Lan; Wu, X; Yamartino, J M; Zheng, M; Zobernig, G

    1996-01-01

    Quark and gluon jets with the same energy, 24GeV, are compared in symmetric three-jet configurations from hadronic Z decays observed by the ALEPH detector. Jets are defined using the Durham algorithm. Gluon jets are identified using an anti-tag on b jets, based on either a track impact parameter method or a high transverse momentum lepton tag. The comparison of gluon and mixed flavour quark jets shows that gluon jets have a softer fragmentation function, a larger angular width and a higher particle multiplicity. Evidence is also presented which shows that the corresponding differences between gluon and heavy flavour jets are significantly smaller.

  20. Jets from ultraluminous X-ray sources

    Science.gov (United States)

    Urquhart, Ryan

    2017-08-01

    An important set of unsolved problems in accretion physics is whether super-Eddington accretion flows produce jets, what the jet power is (compared with the accretion power), and what the large-scale effect of the jet is on the surrounding gas. Most ultraluminous X-ray sources (ULXs) are super-Eddington stellar-mass compact objects: they provide the best local-Universe test of MHD accretion flow simulations. Observational evidence of collimated jets and fast outflows in ULXs may come in different forms: steady synchrotron radio emission from an unresolved, persistent core; radio flaring associated with discrete ejecta; internal shocks along the jet; hotspots from the jet/ISM interaction; hundred-parsec scale wind/jet-inflated nebulae. We discuss examples of the various cases, use them as proxies to measure the jet power, and compare them with (sub-Eddington) AGN and X-ray binary jets.

  1. Airframe-Jet Engine Integration Noise

    Science.gov (United States)

    Tam, Christopher; Antcliff, Richard R. (Technical Monitor)

    2003-01-01

    It has been found experimentally that the noise radiated by a jet mounted under the wing of an aircraft exceeds that of the same jet in a stand-alone environment. The increase in noise is referred to as jet engine airframe integration noise. The objectives of the present investigation are, (1) To obtain a better understanding of the physical mechanisms responsible for jet engine airframe integration noise or installation noise. (2) To develop a prediction model for jet engine airframe integration noise. It is known that jet mixing noise consists of two principal components. They are the noise from the large turbulence structures of the jet flow and the noise from the fine scale turbulence. In this investigation, only the effect of jet engine airframe interaction on the fine scale turbulence noise of a jet is studied. The fine scale turbulence noise is the dominant noise component in the sideline direction. Thus we limit out consideration primarily to the sideline.

  2. Exotic interactions among C-jets and Pb-jets

    Science.gov (United States)

    1985-01-01

    The C-jets and Pb-jets were surveyed on the part of Chacaltaya emulsion chamber No.19 amounting to an exposure of 28.8 sq m yr. It is shown that the adopted events make up an unbiased sample of C-jets for sigma sub E gamma TeV. Mini-Centauro interaction gives the most natural explanation for the eight pinaught-less C-jets with three or more constituent shower core. Out of the eight double-cored pinaught-less events, three are found to have visible invariant masses 1.8 GeV/c. Three Pb-jets-lower are composed of double cores whose respective visible transverse momenta are greater than 0.5 GeV/c, suggesting that they are of Geminion origin or chiron origin. The energies of the parent particles are estimated to be 100 to 200 TeV for all three kinds of events. The implications of this energy estimate and the frequency of observed exotic events are discussed.

  3. Workers exposed to ethylene oxide: a follow up study.

    Science.gov (United States)

    Gardner, M J; Coggon, D; Pannett, B; Harris, E C

    1989-12-01

    A cohort study has been carried out of 2876 men and women with potential exposure to ethylene oxide. Subjects were identified from employment records at four companies that have produced or used ethylene oxide since the 1950s and at eight hospitals which have had ethylene oxide sterilising units since the 1960s. The cohort represents a substantial proportion of the British workforce with a history of occupational exposure to ethylene oxide. Industrial hygiene data were not available before 1977, but since then time weighted average exposures have been less than 5 ppm in almost all jobs and less than 1 ppm in many. Past exposures were probably somewhat higher. In contrast to some previous studies, no clear excess of leukaemia (three deaths observed, 2.09 expected) and no increase in stomach cancer (five deaths observed, 5.95 expected) were found. This discrepancy with earlier reports may be due in part to differences in levels of exposure. Total cancer mortality was similar to that expected from national and local death rates. Some specific cancers showed small excesses but their relevance to ethylene oxide exposure is doubtful. Again, contrary to some earlier reports, no excess of cardiovascular disease was found. This study does not exclude the possibility that ethylene oxide is a human carcinogen but suggests that any risk of cancer from currently permitted occupational exposures is small.

  4. Efficient use of Ethylene Oxide in Vinyl Sulphone Industry

    Directory of Open Access Journals (Sweden)

    Bhavi M. Pandya, Prof. Bharat H. Shah

    2013-04-01

    Full Text Available Vinyl sulphone production includes mainly 4 unit processes which are Chlorosulphonation, Reduction, Condensation, and Esterification. Vinyl sulphone is the highest export dye intermediate. Vinyl sulphone industry in India received a set back in the late nineties due to world competition and insistence on environmental regulations by the controlling authorities. Excess of ethylene oxide is used in condensation, Which is hazardous and it is used in excess as large quantity of Ethylene oxide is reacted with water as a side reaction forming glycols, and also ethylene oxide is soluble in water. So ethylene oxide is wasted in water and increases the volume of reactor. This paper describes to minimize the quantity of water which is causing excess use of ethylene oxide in condensation reaction. Before condensation reaction there are two unit processes Chlorosulphonation and reduction from which we try to limit the quantity of water, so that water coming to condensation reaction is minimized to reduce the side reaction of ethylene oxide and water.

  5. Ethylene Formation by Catalytic Dehydration of Ethanol with Industrial Considerations

    Directory of Open Access Journals (Sweden)

    Ho-Shing Wu

    2012-12-01

    Full Text Available Ethylene is the primary component in most plastics, making it economically valuable. It is produced primarily by steam-cracking of hydrocarbons, but can alternatively be produced by the dehydration of ethanol, which can be produced from fermentation processes using renewable substrates such as glucose, starch and others. Due to rising oil prices, researchers now look at alternative reactions to produce green ethylene, but the process is far from being as economically competitive as using fossil fuels. Many studies have investigated catalysts and new reaction engineering technologies to increase ethylene yield and to lower reaction temperature, in an effort to make the reaction applicable in industry and most cost-efficient. This paper presents various lab synthesized catalysts, reaction conditions, and reactor technologies that achieved high ethylene yield at reasonable reaction temperatures, and evaluates their practicality in industrial application in comparison with steam-cracking plants. The most promising were found to be a nanoscale catalyst HZSM-5 with 99.7% ethylene selectivity at 240 °C and 630 h lifespan, using a microreactor technology with mechanical vapor recompression, and algae-produced ethanol to make ethylene.

  6. KINETICS OF NON-ISOTHERMAL CRYSTALLIZATION OF POLY (ETHYLENE TEREPHTHALATE) MODIFIED BY POLY (ETHYLENE GLYCOL)

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhiying; WU Shizhen; DU Yinghua; CAO Zhenlin

    1991-01-01

    The non-isothermal crystallization kinetics of poly(ethylene terephthalate) (PET) modified by poly (ethlene glycol) (PEG) were determined by DSC. The dual linear regression method was used to evaluate the relationship between the reciprocal of t1/2 ( the half life of crystallization ) and the appropriate temperature variable. The parameters such as the activation energy (Ed) for transport,the equilibrium melting temperature (T0m),the nucleation parameter (ψ),the maximum crystallization temperature (Tc, max ) , and the kinetic crystallizability (G) for the copolyesters were obtained. The influence of the PEG content in PET chains on the parameters characterizing crystallization kinetics and crystallization thermodynamics was discussed.

  7. Biosynthesis of ethylene glycol in Escherichia coli.

    Science.gov (United States)

    Liu, Huaiwei; Ramos, Kristine Rose M; Valdehuesa, Kris Niño G; Nisola, Grace M; Lee, Won-Keun; Chung, Wook-Jin

    2013-04-01

    Ethylene glycol (EG) is an important platform chemical with steadily expanding global demand. Its commercial production is currently limited to fossil resources; no biosynthesis route has been delineated. Herein, a biosynthesis route for EG production from D-xylose is reported. This route consists of four steps: D-xylose → D-xylonate → 2-dehydro-3-deoxy-D-pentonate → glycoaldehyde → EG. Respective enzymes, D-xylose dehydrogenase, D-xylonate dehydratase, 2-dehydro-3-deoxy-D-pentonate aldolase, and glycoaldehyde reductase, were assembled. The route was implemented in a metabolically engineered Escherichia coli, in which the D-xylose → D-xylulose reaction was prevented by disrupting the D-xylose isomerase gene. The most efficient construct produced 11.7 g L(-1) of EG from 40.0 g L(-1) of D-xylose. Glycolate is a carbon-competing by-product during EG production in E. coli; blockage of glycoaldehyde → glycolate reaction was also performed by disrupting the gene encoding aldehyde dehydrogenase, but from this approach, EG productivity was not improved but rather led to D-xylonate accumulation. To channel more carbon flux towards EG than the glycolate pathway, further systematic metabolic engineering and fermentation optimization studies are still required to improve EG productivity.

  8. Jets from Jets: Re-clustering as a tool for large radius jet reconstruction and grooming at the LHC

    CERN Document Server

    Nachman, Benjamin; Schwartzman, Ariel; Swiatlowski, Maximilian

    2014-01-01

    Jets with a large radius $R\\gtrsim 1$ and grooming algorithms are widely used to fully capture the decay products of boosted heavy particles at the Large Hadron Collider (LHC). Unlike most discriminating variables used in such studies, the jet radius is usually not optimized for specific physics scenarios. This is because every jet configuration must be calibrated, insitu, to account for detector response and other experimental effects. One solution to enhance the availability of large-R jet configurations used by the LHC experiments is {\\it jet re-clustering}. Jet re-clustering introduces an intermediate scale $rjets are calibrated and used as the inputs to reconstruct large radius jets. In this paper we systematically study and propose new jet re-clustering configurations and show that re-clustered large radius jets have essentially the same jet mass performance as large radius groomed jets. Jet re-clustering has the benefit that no additional large-R calibration is necessary, allowing the r...

  9. China's first home-made large ethylene unit put into operation in Daqing%China's first home-made large ethylene unit put into operation in Daqing

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    On October 5, the newly built 600kt/a ethylene unit at Daqing Petrochemical, a key part of the company's 1.2Mt/a ethylene expansion/upgrading project, turned out qualified products, indicating the successful industrialization of the packaged technology for China's first home-made large ethylene unit. This enables China to be independent from importing technologies for ethylene production which lasted for halfa century.

  10. Tuning ethylene gas adsorption via metal node modulation: Cu-MOF-74 for a high ethylene deliverable capacity.

    Science.gov (United States)

    Liao, Yijun; Zhang, Lin; Weston, Mitchell H; Morris, William; Hupp, Joseph T; Farha, Omar K

    2017-08-17

    M-MOF-74s were examined for potential applications in ethylene abatement and/or storage/delivery. Due to labile binding resulting from a Jahn-Teller distortion, Cu-MOF-74 exhibits a gradual initial uptake that, in turn, translates into the highest deliverable capacity among the MOFs examined (3.6 mmol g(-1)). In contrast, Co-MOF-74 is the most promising candidate for ethylene abatement due to the sharp uptake at low pressure.

  11. Microscopic Processes in Relativistic Jets

    Science.gov (United States)

    Nishikawa, K.-I.; Hardee, P.; Mizuno, Y.; Medvedev, M.; Zhang, B.; Nordlund, A.; Fredricksen, J.; Sol, H.; Niemiec, J.; Lyubarsky, Y.; hide

    2008-01-01

    Nonthermal radiation observed from astrophysical systems containing relativistic jets and shocks, e.g., gamma-ray bursts (GRBs), active galactic nuclei (AGNs), and Galactic microquasar systems usually have power-law emission spectra. Recent PIC simulations of relativistic electron-ion (electro-positron) jets injected into a stationary medium show that particle acceleration occurs within the downstream jet. In the collisionless relativistic shock particle acceleration is due to plasma waves and their associated instabilities (e.g., the Buneman instability, other two-streaming instability, and the Weibel (filamentation) instability) created in the shocks are responsible for particle (electron, positron, and ion) acceleration. The simulation results show that the Weibel instability is responsible for generating and amplifying highly nonuniform, small-scale magnetic fields. These magnetic fields contribute to the electron's transverse deflection behind the jet head. The 'jitter' radiation from deflected electrons has different properties than synchrotron radiation which is calculated in a uniform magnetic field. This jitter radiation may be important to understanding the complex time evolution and/or spectral structure in gamma-ray bursts, relativistic jets, and supernova remnants.

  12. MHD Jets in inhomogeneous media

    Directory of Open Access Journals (Sweden)

    S. O´Sullivan

    2002-01-01

    Full Text Available Presentamos simulaciones de la propagaci on de jets moleculares no-adiab aticos en un medio ambiente inhomog eneo. Los jets tienen condiciones descritos por un modelo de jet MHD en el cual la forma de las l neas magn eticas se prescribe cerca de la fuente. Per les de densidad ambiental fueron elegidos para representar la zona de transici on entre las regiones exteriores de una nube molecular y el medio interestelar. Escalamos las tasas de enfriamiento at omico y molecular a niveles apropriados para resolver todas las escalas espaciales apropriadas. Con la inclusi on de variabilidad de la fuente, las simulaciones reproducen varias caracter sticas observacionales de jets moleculares, entre ellas las cavidades moleculares. Adicionalmente, encontramos similitudes entre teor a y observaci on para la fracci on de ionizaci on a lo largo del jet. Encontramos que la extensi on lateral de las super cies de trabajo internas son sensibles al medio ambiente. Tambi en presentamos resultados preliminares para un m etodo de calcular mapas de emisi on en l neas usando solamente variables fundamentales de estado que parecen reproducir la emisi on lamentosa de Balmer en frentes de choque.

  13. Supersonic induction plasma jet modeling

    Energy Technology Data Exchange (ETDEWEB)

    Selezneva, S.E. E-mail: svetlana2@hermes.usherbS_Selezneva2@hermes.usherb; Boulos, M.I

    2001-06-01

    Numerical simulations have been applied to study the argon plasma flow downstream of the induction plasma torch. It is shown that by means of the convergent-divergent nozzle adjustment and chamber pressure reduction, a supersonic plasma jet can be obtained. We investigate the supersonic and a more traditional subsonic plasma jets impinging onto a normal substrate. Comparing to the subsonic jet, the supersonic one is narrower and much faster. Near-substrate velocity and temperature boundary layers are thinner, so the heat flux near the stagnation point is higher in the supersonic jet. The supersonic plasma jet is characterized by the electron overpopulation and the domination of the recombination over the dissociation, resulting into the heating of the electron gas. Because of these processes, the supersonic induction plasma permits to separate spatially different functions (dissociation and ionization, transport and deposition) and to optimize each of them. The considered configuration can be advantageous in some industrial applications, such as plasma-assisted chemical vapor deposition of diamond and polymer-like films and in plasma spraying of nanoscaled powders.

  14. Nanofluid impingement jet heat transfer.

    Science.gov (United States)

    Zeitoun, Obida; Ali, Mohamed

    2012-02-17

    Experimental investigation to study the heat transfer between a vertical round alumina-water nanofluid jet and a horizontal circular round surface is carried out. Different jet flow rates, jet nozzle diameters, various circular disk diameters and three nanoparticles concentrations (0, 6.6 and 10%, respectively) are used. The experimental results indicate that using nanofluid as a heat transfer carrier can enhance the heat transfer process. For the same Reynolds number, the experimental data show an increase in the Nusselt numbers as the nanoparticle concentration increases. Size of heating disk diameters shows reverse effect on heat transfer. It is also found that presenting the data in terms of Reynolds number at impingement jet diameter can take into account on both effects of jet heights and nozzle diameter. Presenting the data in terms of Peclet numbers, at fixed impingement nozzle diameter, makes the data less sensitive to the percentage change of the nanoparticle concentrations. Finally, general heat transfer correlation is obtained verses Peclet numbers using nanoparticle concentrations and the nozzle diameter ratio as parameters.

  15. Plasma Jet Modeling for PLX

    Science.gov (United States)

    Mason, Caroline F.; Mason, Rodney J.; Faehl, R. J.; Kirkpatrick, R. C.

    2011-10-01

    The implicit simulation code ePLAS has been applied to plasma jets generated with mini-rail guns for plasma production and compression aimed at use with PLX. The rails are typically planar, 2.5 cm apart and arranged to transport an initial 1 cm or wider vertical plasma fill some 10 cm into a void. The driving magnetic field is 3.2 T. The plasma singly ionized argon at 1017 cm-3. We use ePLAS in both its traditional implicit/hybrid form where it is restricted by an electron Courant time step, and in a new super-hybrid form that extracts the main electron moments from the E&B-field solutions. This provides numerical stability at ion Courant limits, for at least a 10 times larger time step, thus probing microsecond jet dynamics with computational economy. We examine possible field penetration at the cathode and anode gun electrodes. Cathode erosion and EMHD B - Field penetration are possible at lower jet densities. We examine jet transport beyond the gun, modeling possible ionization with either analytic or tabular EOSs. We study the merger of jets with ions represented as either fluids or particles. Work supported by the USDOE under SBIR GRANT DE-SC0004207.

  16. Coadsorption of ethylene and potassium on Pt(111). 1. Formation of a. pi. -bonded state of ethylene

    Energy Technology Data Exchange (ETDEWEB)

    Windham, R.G.; Bartram, M.E.; Koel, B.E.

    1988-05-19

    High resolution electron energy spectroscopy (HREELS), temperature-programmed desorption (TPD), and ultraviolet photoelectron spectroscopy (UPS) have been combined to study the effect of preadsorbed potassium on the adsorption of ethylene on the platinum(111) single-crystal surface. Addition of potassium increases the relative amount of reversible ethylene adsorption at 100 K/. Upon coadsorption with potassium, the authors also observe a new low-temperature ethylene desorption state at 150 K, with E/sub d/ = 5-9 kcal mol/sup -1/, which is about one-half the binding energy of ethylene adsorbed on clean Pt(111). The origin of this new desorption state is the formation of a weakly interacting ethylene species, which is only slightly distorted from the gas-phase hybridization, as determined primarily by vibrational spectroscopy. An explanation is given for these effects in which the increased charge density at the platinum surface due to coadsorbed potassium inhibits the strong sigma-donation of adsorbed ethylene to platinum and greatly reduces the chemisorption bond strength.

  17. Jet flow and premixed jet flame control by plasma swirler

    Science.gov (United States)

    Li, Gang; Jiang, Xi; Zhao, Yujun; Liu, Cunxi; Chen, Qi; Xu, Gang; Liu, Fuqiang

    2017-04-01

    A swirler based on dielectric barrier discharge plasma actuators is designed and its effectiveness in both jet flow and premixed jet flame control is demonstrated. In contrast to traditional spanwise-oriented actuators, plasma actuators are placed along the axial direction of the injector to induce a circumferential velocity to the main flow and create a swirl flow without any insertion or moving part. In the DBD plasma swirl injector, the discharge does not ignite the mixture nor does it induce flashback. Flame visualization is obtained by cameras while velocity profiles are obtained by Laser Doppler Anemometry measurements. The results obtained indicate the effectiveness of the new design.

  18. N2稀释对双旋流合成气非预混燃烧特性的影响%Effect of N2 Dilution on Flame Structures of a Double-Swirled Non-Premixed Syngas Flame

    Institute of Scientific and Technical Information of China (English)

    葛冰; 臧述升; 郭培卿; 田寅申

    2012-01-01

    Experiments have been performed to investigate the effect of N2 dilution on the flame structures of a double-swirled non-premixed syngas flames. Planar laser induced fluorescence (PLIF) of OH-radical measurement is adopted to identify main reaction zones and burnt gas regions. Together with temperature and emission measurement during exhaust section, some important characteristics of the syngas flame are overall investigated. Experimental result shows that syngas flame root near the burner exit demonstrates double flame front structure. The existence of N2 expands the flame opening angle and enlarges the main reaction zone, and it may lead to lower NO emission and higher CO emission in exhaust gas.%利用平面激光诱导荧光(PLIF)、高温细丝热电偶及红外气体分析仪对不同N2稀释量下的双旋流合成气非燃烧流场进行了实验研究。实验结果表明,随着N2稀释量的增加:双旋流合成气火焰的基本结构发生变化,火焰会出现典型的推举火焰特征;火焰锋面被拉伸,主要反应区域轴向长度和径向宽度增大,喷嘴出口附近火焰锋面由M型分布逐渐转变为W型分布,轴线上未反应区域不断扩大;火焰张角与穿透深度增大,火焰推举高度减小;燃烧排气温度略有减小,NO排放明显降低。

  19. The first calculation of fractional jets

    Energy Technology Data Exchange (ETDEWEB)

    Bertolini, Daniele [Ernest Orlando Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Center for Theoretical Physics, University of California, Berkeley, CA 94720 (United States); Thaler, Jesse [Center for Theoretical Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Walsh, Jonathan R. [Ernest Orlando Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Center for Theoretical Physics, University of California, Berkeley, CA 94720 (United States)

    2015-05-04

    In collider physics, jet algorithms are a ubiquitous tool for clustering particles into discrete jet objects. Event shapes offer an alternative way to characterize jets, and one can define a jet multiplicity event shape, which can take on fractional values, using the framework of “jets without jets”. In this paper, we perform the first analytic studies of fractional jet multiplicity N-tilde{sub jet} in the context of e{sup +}e{sup −} collisions. We use fixed-order QCD to understand the N-tilde{sub jet} cross section at order α{sub s}{sup 2}, and we introduce a candidate factorization theorem to capture certain higher-order effects. The resulting distributions have a hybrid jet algorithm/event shape behavior which agrees with parton shower Monte Carlo generators. The N-tilde{sub jet} observable does not satisfy ordinary soft-collinear factorization, and the N-tilde{sub jet} cross section exhibits a number of unique features, including the absence of collinear logarithms and the presence of soft logarithms that are purely non-global. Additionally, we find novel divergences connected to the energy sharing between emissions, which are reminiscent of rapidity divergences encountered in other applications. Given these interesting properties of fractional jet multiplicity, we advocate for future measurements and calculations of N-tilde{sub jet} at hadron colliders like the LHC.

  20. Surface modification of poly(ethylene terephthalate) by plasma polymerization of poly(ethylene glycol).

    Science.gov (United States)

    Sakthi Kumar, D; Fujioka, Masayori; Asano, Kentaro; Shoji, Atsumu; Jayakrishnan, Athipettah; Yoshida, Yasuhiko

    2007-09-01

    Poly(ethylene glycol) (PEG) was 'polymerized' onto poly(ethylene terephthalate) (PET) surface by radio frequency (RF) plasma polymerization of PEG (average molecular weight 200 Da) at a monomer vapour partial pressure of 10 Pa. Thin films strongly adherent onto PET could be produced by this method. The modified surface was characterized by infra red (IR) spectroscopy, scanning electron microscopy (SEM), atomic force microscopy (AFM), cross-cut test, contact angle measurements and static platelet adhesion studies. The modified surface, believed to be extensively cross-linked, however showed all the chemical characteristics of PEG. The surface was found to be highly hydrophilic as evidenced by an interfacial free energy of about 0.7 dynes/cm. AFM studies showed that the surface of the modified PET became smooth by the plasma polymerized deposition. Static platelet adhesion studies using platelet rich plasma (PRP) showed considerably reduced adhesion of platelets onto the modified surface by SEM. Plasma 'polymerization' of a polymer such as PEG onto substrates may be a novel and interesting strategy to prepare PEG-like surfaces on a variety of substrates since the technique allows the formation of thin, pin-hole free, strongly adherent films on a variety of substrates.

  1. Surface Plasmon Resonance Sensor Based on Ethylene Tetra-Fluoro-Ethylene Hollow Fiber

    Directory of Open Access Journals (Sweden)

    Pan Chen

    2015-11-01

    Full Text Available A new kind of hollow fiber surface plasmon resonance sensor (HF-SPRS based on the silver-coated ethylene tetra-fluoro-ethylene (ETFE hollow fiber (HF is presented. The ETFE HF-SPRS is fabricated, and its performance is investigated experimentally by measuring the transmission spectra of the sensor when filled by liquid sensed media with different refractive indices (RIs. Theoretical analysis based on the ray transmission model is also taken to evaluate the sensor. Because the RI of ETFE is much lower than that of fused silica (FSG, the ETFE HF-SPRS can extend the lower limit of the detection range of the early reported FSG HF-SPRS from 1.5 to 1.42 approximately. This could greatly enhance the application potential of HF-SPRS. Moreover, the joint use of both ETFE and FSG HF-SPRSs can cover a wide detection range from 1.42 to 1.69 approximately with high sensitivities larger than 1000 nm/RIU.

  2. Evaluation of workers exposed to ethylene glycol monomethyl ether and ethylene glycol monomethyl ether acetate.

    Science.gov (United States)

    Park, Jiyoung; Yoon, Chungsik; Byun, Hyaejeong; Kim, Yangho; Park, Donguk; Ha, Kwonchul; Lee, Sang man; Park, Sungki; Chung, Eunkyo

    2012-01-01

    Ethylene glycol monomethyl ether (EGME) and ethylene glycol monomethyl ether acetate (EGMEA) are widely used in industries as solvents for coatings, paint and ink, but exposure data are limited because they are minor components out of mixed solvents, as well as because of inconsistency in desorption solvent use. The objective of this study was to investigate the worker exposure profile of EGME and EGMEA. Our study investigated 27 workplaces from June to September 2008 and detected EGME and EGMEA in 20 and 13, respectively. Both personal and area sampling were conducted using a charcoal tube to collect EGME and EGMEA. Gas chromatography with a flame ionization detector was used to analyze these compounds after desorption using a mixture of methylene chloride and methanol. The arithmetic mean concentrations of EGME and EGMEA during periods of full work shifts were 2.59 ppm and 0.33 ppm, respectively. The exposure levels were lower than the Korean Ministry of Labor (MOL) OEL (5 ppm) but higher than the ACGIH TLV (0.1 ppm). In general, the working environments were poor and required much improvement, including the use of personal protective equipment. Only 50% of the workplaces had local exhaust ventilation systems in operation. The average capture velocity of the operating local exhaust ventilation systems was 0.27 m/s, which did not meet the legal requirement of 0.5 m/s. Educating workers to clearly understand the handling and use of hazardous chemicals and improving working conditions are strongly suggested.

  3. Two Jet Production at CDF

    Energy Technology Data Exchange (ETDEWEB)

    Dell' Agnello, Simone; /INFN, Pisa

    1989-01-01

    CDF (Collider Detector at Fermilab) is a full-coverage magnetic detector studying p{bar p} collisions at the {radical}s = 1.8 TeV Tevatron Collider. The experiment has collected a handful of demonstration events towards the end 1985, and had its first significant run in spring 1987. Most of this run was operated with a 'buffet trigger', one stream of which was an inclusive large-E{sub t} trigger. Large E{sub t} (E{sub t} >50 GeV) events at the Tevatron show an increasingly dominant component with two or more hard jets. This thesis consists in an analysis of these jet events. The invariant cross-secton as a function of jet pair mass (M{sub jj}) is derived.

  4. Dye Aggregation in Ink Jet

    Institute of Scientific and Technical Information of China (English)

    Thomas Paul; Sarfraz Hussain

    2004-01-01

    Dye aggregation has long been recognised as a key factor in performance, and this is no less so in ink jet applications. The aggregation state was shown to be important in many different areas ranging from the use of dyes in photodynamic therapies all the way to colorants for dying of fabrics. Therefore different methods to investigate dye association qualitatively and quantitatively were developed. A simple procedure to study aggregation could be a useful tool to characterise dyes for ink jet printing. It is critically reviewed the methods used to study dye aggregation, and discussed some of the main conclusions. This will be illustrated by examples of ink jet dye aggregation and its study in aqueous and ink systems. The results are used to correlate the solution behaviour of dyes with their print performance.

  5. Peptides interfering with protein-protein interactions in the ethylene signaling pathway delay tomato fruit ripening

    Science.gov (United States)

    Bisson, Melanie M. A.; Kessenbrock, Mareike; Müller, Lena; Hofmann, Alexander; Schmitz, Florian; Cristescu, Simona M.; Groth, Georg

    2016-08-01

    The plant hormone ethylene is involved in the regulation of several processes with high importance for agricultural applications, e.g. ripening, aging and senescence. Previous work in our group has identified a small peptide (NOP-1) derived from the nuclear localization signal of the Arabidopsis ethylene regulator ETHYLENE INSENSITIVE-2 (EIN2) C-terminal part as efficient inhibitor of ethylene responses. Here, we show that NOP-1 is also able to efficiently disrupt EIN2-ETR1 complex formation in tomato, indicating that the NOP-1 inhibition mode is conserved across plant species. Surface application of NOP-1 on green tomato fruits delays ripening similar to known inhibitors of ethylene perception (MCP) and ethylene biosynthesis (AVG). Fruits treated with NOP-1 showed similar ethylene production as untreated controls underlining that NOP-1 blocks ethylene signaling by targeting an essential interaction in this pathway, while having no effect on ethylene biosynthesis.

  6. Auxin and ethylene induce flavonol accumulation through distinct transcriptional networks.

    Science.gov (United States)

    Lewis, Daniel R; Ramirez, Melissa V; Miller, Nathan D; Vallabhaneni, Prashanthi; Ray, W Keith; Helm, Richard F; Winkel, Brenda S J; Muday, Gloria K

    2011-05-01

    Auxin and ethylene are key regulators of plant growth and development, and thus the transcriptional networks that mediate responses to these hormones have been the subject of intense research. This study dissected the hormonal cross talk regulating the synthesis of flavonols and examined their impact on root growth and development. We analyzed the effects of auxin and an ethylene precursor on roots of wild-type and hormone-insensitive Arabidopsis (Arabidopsis thaliana) mutants at the transcript, protein, and metabolite levels at high spatial and temporal resolution. Indole-3-acetic acid (IAA) and 1-aminocyclopropane-1-carboxylic acid (ACC) differentially increased flavonol pathway transcripts and flavonol accumulation, altering the relative abundance of quercetin and kaempferol. The IAA, but not ACC, response is lost in the transport inhibitor response1 (tir1) auxin receptor mutant, while ACC responses, but not IAA responses, are lost in ethylene insensitive2 (ein2) and ethylene resistant1 (etr1) ethylene signaling mutants. A kinetic analysis identified increases in transcripts encoding the transcriptional regulators MYB12, Transparent Testa Glabra1, and Production of Anthocyanin Pigment after hormone treatments, which preceded increases in transcripts encoding flavonoid biosynthetic enzymes. In addition, myb12 mutants were insensitive to the effects of auxin and ethylene on flavonol metabolism. The equivalent phenotypes for transparent testa4 (tt4), which makes no flavonols, and tt7, which makes kaempferol but not quercetin, showed that quercetin derivatives are the inhibitors of basipetal root auxin transport, gravitropism, and elongation growth. Collectively, these experiments demonstrate that auxin and ethylene regulate flavonol biosynthesis through distinct signaling networks involving TIR1 and EIN2/ETR1, respectively, both of which converge on MYB12. This study also provides new evidence that quercetin is the flavonol that modulates basipetal auxin transport.

  7. Advanced thermally stable jet fuels

    Energy Technology Data Exchange (ETDEWEB)

    Schobert, H.H.

    1999-01-31

    The Pennsylvania State University program in advanced thermally stable coal-based jet fuels has five broad objectives: (1) Development of mechanisms of degradation and solids formation; (2) Quantitative measurement of growth of sub-micrometer and micrometer-sized particles suspended in fuels during thermal stressing; (3) Characterization of carbonaceous deposits by various instrumental and microscopic methods; (4) Elucidation of the role of additives in retarding the formation of carbonaceous solids; (5) Assessment of the potential of production of high yields of cycloalkanes by direct liquefaction of coal. Future high-Mach aircraft will place severe thermal demands on jet fuels, requiring the development of novel, hybrid fuel mixtures capable of withstanding temperatures in the range of 400--500 C. In the new aircraft, jet fuel will serve as both an energy source and a heat sink for cooling the airframe, engine, and system components. The ultimate development of such advanced fuels requires a thorough understanding of the thermal decomposition behavior of jet fuels under supercritical conditions. Considering that jet fuels consist of hundreds of compounds, this task must begin with a study of the thermal degradation behavior of select model compounds under supercritical conditions. The research performed by The Pennsylvania State University was focused on five major tasks that reflect the objectives stated above: Task 1: Investigation of the Quantitative Degradation of Fuels; Task 2: Investigation of Incipient Deposition; Task 3: Characterization of Solid Gums, Sediments, and Carbonaceous Deposits; Task 4: Coal-Based Fuel Stabilization Studies; and Task 5: Exploratory Studies on the Direct Conversion of Coal to High Quality Jet Fuels. The major findings of each of these tasks are presented in this executive summary. A description of the sub-tasks performed under each of these tasks and the findings of those studies are provided in the remainder of this volume

  8. Generalized fragmentation functions for fractal jet observables

    Science.gov (United States)

    Elder, Benjamin T.; Procura, Massimiliano; Thaler, Jesse; Waalewijn, Wouter J.; Zhou, Kevin

    2017-06-01

    We introduce a broad class of fractal jet observables that recursively probe the collective properties of hadrons produced in jet fragmentation. To describe these collinear-unsafe observables, we generalize the formalism of fragmentation functions, which are important objects in QCD for calculating cross sections involving identified final-state hadrons. Fragmentation functions are fundamentally nonperturbative, but have a calculable renormalization group evolution. Unlike ordinary fragmentation functions, generalized fragmentation functions exhibit nonlinear evolution, since fractal observables involve correlated subsets of hadrons within a jet. Some special cases of generalized fragmentation functions are reviewed, including jet charge and track functions. We then consider fractal jet observables that are based on hierarchical clustering trees, where the nonlinear evolution equations also exhibit tree-like structure at leading order. We develop a numeric code for performing this evolution and study its phenomenological implications. As an application, we present examples of fractal jet observables that are useful in discriminating quark jets from gluon jets.

  9. QCD and jets at hadron colliders

    Science.gov (United States)

    Sapeta, Sebastian

    2016-07-01

    We review various aspects of jet physics in the context of hadron colliders. We start by discussing the definitions and properties of jets and recent development in this area. We then consider the question of factorization for processes with jets, in particular for cases in which jets are produced in special configurations, like for example in the region of forward rapidities. We review numerous perturbative methods for calculating predictions for jet processes, including the fixed-order calculations as well as various matching and merging techniques. We also discuss the questions related to non-perturbative effects and the role they play in precision jet studies. We describe the status of calculations for processes with jet vetoes and we also elaborate on production of jets in forward direction. Throughout the article, we present selected comparisons between state-of-the-art theoretical predictions and the data from the LHC.

  10. QCD and Jets at Hadron Colliders

    CERN Document Server

    Sapeta, Sebastian

    2016-01-01

    We review various aspects of jet physics in the context of hadron colliders. We start by discussing the definitions and properties of jets and recent development in this area. We then consider the question of factorization for processes with jets, in particular for cases in which jets are produced in special configurations, like for example in the region of forward rapidities. We review numerous perturbative methods for calculating predictions for jet processes, including the fixed-order calculations as well as various matching and merging techniques. We also discuss the questions related to non-perturbative effects and the role they play in precision jet studies. We describe the status of calculations for processes with jet vetoes and we also elaborate on production of jets in forward direction. Throughout the article, we present selected comparisons between state-of-the-art theoretical predictions and the data from the LHC.

  11. Magnetohydrodynamic Origin of Jets from Accretion Disks

    CERN Document Server

    Lovelace, R V E; Koldoba, A V

    1999-01-01

    A review is made of recent magnetohydrodynamic (MHD) theory and simulations of origin of jets from accretion disks. Many compact astrophysical objects emit powerful, highly-collimated, oppositely directed jets. Included are the extra galactic radio jets of active galaxies and quasars, and old compact stars in binaries, and emission line jets in young stellar objects. It is widely thought that these different jets arise from rotating, conducting accretion disks threaded by an ordered magnetic field. The twisting of the magnetic field by the rotation of the disk drives the jets by magnetically extracting matter, angular momentum, and energy from the accretion disk. Two main regimes have been discussed theoretically, hydromagnetic winds which have a significant mass flux, and Poynting flux jets where the mass flux is negligible. Over the past several years, exciting new developments on models of jets have come from progress in MHD simulations which now allow the study of the origin - the acceleration and collima...

  12. Quark vs Gluon Jet Tagging at ATLAS

    CERN Document Server

    Rubbo, Francesco; The ATLAS collaboration

    2017-01-01

    Distinguishing quark-initiated from gluon-initiated jets is useful for many measurements and searches at the LHC. We present a quark-initiated versus gluon-initiated jet tagger from the ATLAS experiment using the number of reconstructed charged particles inside the jet. The measurement of the charged-particle multiplicity inside jets from Run 1 is used to derive uncertainties on the tagger performance for Run 2. With an efficiency of 60% to select quark-initiated jets, the efficiency to select gluon-initiated jets is between 10 and 20% across a wide range in jet pT up to 1.5 TeV with about an absolute 5% systematic uncertainty on the efficiencies. In addition, we also present preliminary studies on a tagger for the ATLAS experiment using the full radiation pattern inside a jet processed as images in deep neural network classifiers.

  13. Nonlinear Dynamics of Coiling in Viscoelastic Jets

    CERN Document Server

    Majmudar, Trushant; Hartt, William; McKinley, Gareth

    2010-01-01

    Instabilities in free surface continuous jets of non-Newtonian fluids, although relevant for many industrial processes, remain less well understood in terms of fundamental fluid dynamics. Inviscid, and viscous Newtonian jets have been studied in great detail; buckling instability in viscous jets leads to regular periodic coiling of the jet that exhibits a non-trivial frequency dependence with the height of the fall. Very few experimental or theoretical studies exist for continuous viscoelastic jets beyond the onset of the first instability. Here, we present a systematic study of the effects of viscoelasticity on the dynamics of free surface continuous jets of surfactant solutions that form worm-like micelles. We observe complex nonlinear spatio-temporal dynamics of the jet and uncover a transition from periodic to doubly-periodic or quasi-periodic to a multi-frequency, possibly chaotic dynamics. Beyond this regime, the jet dynamics smoothly crosses over to exhibit the "leaping shampoo effect" or the Kaye effe...

  14. HF Transverse Segmentation and Tagging Jet Capability

    CERN Document Server

    Doroshkevich, E A; Kuleshov, Sergey

    1998-01-01

    So called tagging jets and pile-up were simulated for the optimisation of the HF segmentation. The energy resolution, angular resolution and efficiency of jet reconstruction are defined for different calorimeter segmentation.

  15. ATLAS jet trigger performance in 2015 data

    CERN Document Server

    Herwig, Theodor Christian; The ATLAS collaboration

    2016-01-01

    The ATLAS experiment at the LHC uses a two-level trigger system to preferentially select events with a predefined topology of interest for future analysis. The hadronic jet trigger is used to select several different topologies containing different types and multiplicities of hadronic jets, thus supporting many different physics searches and measurements. The hadronic jet trigger efficiency for proton-proton collision data at a centre-of-mass energy of 13 TeV is presented. The efficient selection of events containing hadronic jets requires the characteristics of trigger-level jets and offline jets to be very similar. A comparison of relevant characteristics demonstrates that trigger-level jets and offline jets are in excellent agreement.

  16. ATLAS jet trigger performance in 2016 data

    CERN Document Server

    Herwig, Theodor Christian; The ATLAS collaboration

    2016-01-01

    The ATLAS experiment at the LHC uses a two-level trigger system to preferentially select events with a predefined topology of interest for future analysis. The hadronic jet trigger is used to select several different topologies containing different types and multiplicities of hadronic jets, thus supporting many different physics searches and measurements. The hadronic jet trigger efficiency for proton-proton collision data at a centre-of-mass energy of 13 TeV is presented. The efficient selection of events containing hadronic jets requires the characteristics of trigger-level jets and offline jets to be very similar. A comparison of relevant characteristics demonstrates that trigger-level jets and offline jets are in excellent agreement.

  17. Jets in deep inelastic electroproduction

    CERN Document Server

    Drews, G; Erickson, R; Gebert, W; Janata, F; Joos, P; Ladage, A; Messing, F; Nagel, H; Nordberg, E; Preissner, H; Sadoff, A; Siemann, R; Smith-Kintner, J; Söding, P; Stein, P

    1979-01-01

    Results on jet structure of the hadronic final state in electron- proton scattering are presented. The kinematic range includes 1jet axis determined with sphericity or thrust and the direction of the virtual photon is measured. Comparison with data from e/sup +/e /sup -/ annihilation is made. A method to estimate the intrinsic transverse momentum of the quark in the target proton is presented. (8 refs).

  18. Stagnation knots in precessing Jets

    Directory of Open Access Journals (Sweden)

    Andrew J. Lim

    2002-01-01

    Full Text Available Se investiga el problema de la formaci on de nudos de estancamiento en la cabeza de un jet estelar en precesi on desde los puntos de vista anal tico y num erico. Esta estructura de alta densidad se forma v a un m etodo similar al que propuso Ste en (estas memorias para la formaci on de FLIERs en nebulosas planetarias. Resultados iniciales sugieren que la formaci on de un nudo de estancamiento posiblemente sea una inestabilidad intr nseca de jets en precesi on.

  19. V+jets from CMS

    CERN Document Server

    Hortiangtham, Apichart

    2016-01-01

    The production of vector bosons (V = W, Z or $\\gamma$) in association with jets is a stringent test of perturbative QCD and is a background process in searches for new physics. Total and differential cross-section measurements of vector bosons produced in association with jets (and heavy flavour quarks) are presented. The data have been recorded with the CMS detector at the LHC and are compared to next-to leading order calculations and event simulations that devise matrix element calculations interfaced with parton showers.

  20. Study of Several Impinging Jets

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Impinging Jets are frequently adapted for cooling overheated parts.With the film cooling technique,this process improves thermal exchanges between walls and fluid.However if many works have concerned only the thermal aspect of this problem[1],its dynamic field has been rarely studied especially for multiple impingements.As the two phenomena caanot be totally dissociated.we have undertaken the aerodynamic and thermal study of jets impinging on a aplane wall,Various techniques,have been used as visualizations(spreading over method.LASER sheet visualizations),LDA measurements to propose a topology schema of the flow and infraed thermography.

  1. Physical factors of primary jet vectoring control using synthetic jet actuators

    Institute of Scientific and Technical Information of China (English)

    XIA Zhi-xun; LUO Zhen-bing

    2007-01-01

    A primary jet vectoring using synthetic jet actuators with different exit configurations was investigated, and the main physical factors influencing jet vectoring were analyzed and summarized. The physical factors of the pressure difference, the location and area of the lower pressure region, the component of the synthetic jet momentum and the entrainment ratio of the synthetic jet flow to primary jet flow directly control the vectoring force and the vectoring angle. Three characteristic parameters of the synthetic jet contribute to the pressure difference and the area of the lower pressure region Both the extension step and slope angle of the actuator exit have functions of regulating the location of the lower pressure region, the area of the lower pressure region, and the entrainment ratio of the synthetic jet flow to primary jet flow. The slope angle of the actuator exit has additional functions of regulating the component of the synthetic jet momentum. Based upon analyzing the physical factors of jet vectoring control with synthetic jets, the source variables of the physical factors were established. A preparatory control model of jet vectoring using synthetic jet actuator was presented, and it has the benefit of explaining the efficiency of jet vectoring using synthetic jet actuator with source variables at different values, and it indicates the optimal actuator is taking full advantage of the regulating function.

  2. Multiple Jets at the LHC with High Energy Jets

    DEFF Research Database (Denmark)

    Andersen, Jeppe Rosenkrantz; Smillie, Jennifer M.

    2011-01-01

    -level accuracy for multiplicities up to 4 jets. The resummation includes all-order hard corrections, which become important for increasing centre-of-mass energy of the hadronic collision. We discuss observables relevant for confronting the perturbative framework with 7 TeV data from the LHC, and the impact...

  3. Inclusive jet production at the Tevatron

    Energy Technology Data Exchange (ETDEWEB)

    Norniella, Olga; /Barcelona, IFAE

    2006-08-01

    Preliminary results on inclusive jet production in proton-antiproton collisions at {radical}s = 1.96 TeV based on 1 fb{sup -1} of CDF Run II data are presented. Measurements are preformed using different jet algorithms in a wide range of jet transverse momentum and jet rapidity. The measured cross sections are compared to next-to-leading order perturbative QCD calculations

  4. Charm jet identification at the CMS experiment

    CERN Document Server

    Moortgat, Seth

    2016-01-01

    Identification of jets originating from c quarks becomes more and more important for a wide variety of standard model physics as well as searches for physics beyond the standard model. Recently, the CMS collaboration developed a charm-jet algorithm, trained to discriminate against b jets and light-quark or gluon jets. In this presentation, we will describe this newly developed algorithm and present its performance on the 13 TeV data.

  5. Academic Training Lecture: Jets at Hadron Colliders

    CERN Multimedia

    PH Department

    2011-01-01

    Regular Programme 30, 31 March and 1 April  2011 from 11:00 to 12:00 -  Bldg. 40-S2-A01 - Salle Andersson Jets at Hadron Colliders by Gavin Salam These three lectures will discuss how jets are defined at hadron colliders, the physics that is responsible for the internal structure of jets and the ways in which an understanding of jets may help in searches for new particles at the LHC.

  6. REVIEW OF WATER JET APPLICATIONS IN MANUFACTURING

    OpenAIRE

    Faruk MENDİ; KÜLEKÇİ, Mustafa Kemal

    1999-01-01

    Usage of water jets in manufacturing processes, has been known for many decades. A wide range of engineering materials can be cut by water jets with satisfactory results. Enhanced reliability and efficiency of the technique, have yielded the technology greater interest for manufacturing applications. Water jets are used to cut soft materials such as wood, plastics, aluminium and copper. Abrasive water jets are used to cut very hard materials such as titanium, inconel, glass and ceramics. It i...

  7. The Georgi Algorithms of Jet Clustering

    OpenAIRE

    Ge, Shao-Feng

    2014-01-01

    We reveal the direct link between the jet clustering algorithms recently proposed by Howard Georgi and parton shower kinematics, providing firm foundation from the theoretical side. The kinematics of this class of elegant algorithms is explored systematically for partons with arbitrary masses and the jet function is generalized to $J^{(n)}_\\beta$ with a jet function index $n$ in order to achieve more degrees of freedom. Based on three basic requirements that, the result of jet clustering is p...

  8. Effects of mean shear and scalar initial length scale on three-scalar mixing in turbulent coaxial jets

    Science.gov (United States)

    Tong, Chenning; Li, Wei; Yuan, Mengyuan; Carter, Campbell

    2016-11-01

    We investigate three-scalar mixing in a turbulent coaxial jet, in which a center jet and an annular flow, consisting of acetone-doped air and ethylene respectively, are mixed with the co-flow air. We investigate the effects of the velocity and length scale ratios of the annular flow to the center jet. Planar laser-induced fluorescence and Rayleigh scattering are employed to image the scalars. The results show that the velocity ratio alters the relative mean shear rates in the mixing layers between the center jet and the annular flow and between the annular flow and the co-flow, modifying the scalar fields through mean-flow advection, turbulent transport, and small-scale mixing. The length scale ratio determines the degree of separation between the center jet and the co-flow. The results show that while varying the velocity ratio can alter the mixing characteristics qualitatively, varying the annulus width only has quantitative effects. The evolution of the mean scalar profiles are dominated by the mean-flow advection, while the shape of the joint probability density function is largely determined by the turbulent transport and molecular diffusion. The results in the present study have implications for understanding and modeling multiscalar mixing in turbulent reactive flows. Supported by NSF.

  9. JetCurry: Modeling 3D geometry of AGN jets from 2D images

    Science.gov (United States)

    Kosak, Katie; Li, KunYang; Avachat, Sayali S.; Perlman, Eric S.

    2017-02-01

    Written in Python, JetCurry models the 3D geometry of jets from 2-D images. JetCurry requires NumPy and SciPy and incorporates emcee (ascl:1303.002) and AstroPy (ascl:1304.002), and optionally uses VPython. From a defined initial part of the jet that serves as a reference point, JetCurry finds the position of highest flux within a bin of data in the image matrix and fits along the x axis for the general location of the bends in the jet. A spline fitting is used to smooth out the resulted jet stream.

  10. Jet flow in steadily swimming adult squid.

    Science.gov (United States)

    Anderson, Erik J; Grosenbaugh, Mark A

    2005-03-01

    Although various hydrodynamic models have been used in past analyses of squid jet propulsion, no previous investigations have definitively determined the fluid structure of the jets of steadily swimming squid. In addition, few accurate measurements of jet velocity and other jet parameters in squid have been reported. We used digital particle imaging velocimetry (DPIV) to visualize the jet flow of adult long-finned squid Loligo pealei (mantle length, L(m)=27.1+/-3.0 cm, mean +/-S.D.) swimming in a flume over a wide range of speeds (10.1-59.3 cm s(-1), i.e. 0.33-2.06 L(m) s(-1)). Qualitatively, squid jets were periodic, steady, and prolonged emissions of fluid that exhibited an elongated core of high speed flow. The development of a leading vortex ring common to jets emitted from pipes into still water often appeared to be diminished and delayed. We were able to mimic this effect in jets produced by a piston and pipe arrangement aligned with a uniform background flow. As in continuous jets, squid jets showed evidence of the growth of instability waves in the jet shear layer followed by the breakup of the jet into packets of vorticity of varying degrees of coherence. These ranged from apparent chains of short-lived vortex rings to turbulent plumes. There was some evidence of the complete roll-up of a handful of shorter jets into single vortex rings, but steady propulsion by individual vortex ring puffs was never observed. Quantitatively, the length of the jet structure in the visualized field of view, L(j), was observed to be 7.2-25.6 cm, and jet plug lengths, L, were estimated to be 4.4-49.4 cm using average jet velocity and jet period. These lengths and an average jet orifice diameter, D, of 0.8 cm were used to calculate the ratios L(j)/D and L/D, which ranged from 9.0 to 32.0 and 5.5 to 61.8, respectively. Jets emitted from pipes in the presence of a background flow suggested that the ratio between the background flow velocity and the jet velocity was more

  11. Jet quenching and γ-jet correlation in high-energy heavy-ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xin-Nian [Key Laboratory of Quark and Lepton Physics (MOE) and Institute of Particle Physics, Central China Normal University, Wuhan 430079 (China); Nuclear Science Division Mailstop 70R0319, Lawrence Berkeley National Laboratory, Berkeley, CA 94740 (United States); Zhu, Yan [Departamento de Física de Partículas and IGFAE, Universidade de Santiago de Compostela, E-15706 Santiago de Compostela, Galicia (Spain)

    2014-12-15

    Medium modification of γ-tagged jets in high-energy heavy-ion collisions is investigated within a linearized Boltzmann transport model which includes both elastic parton scattering and induced gluon emission. In Pb + Pb collisions at √(s)=2.76 TeV, a γ-tagged jet is seen to lose 15% of its energy at 0–10% central collisions. Simulations also point to a sizable azimuthal angle broadening of γ-tagged jets at the tail of a distribution which should be measurable when experimental errors are significantly reduced. An enhancement at large z{sub jet}=p{sub L}/E{sub jet} in jet fragmentation function at the Large Hadron Collider (LHC) can be attributed to the dominance of leading particles in the reconstructed jet. A γ-tagged jet fragmentation function is shown to be more sensitive to jet quenching, therefore a better probe of the jet transport parameter.

  12. Effects of Ethephon, Ethylene, and 2,4-Dichlorophenoxyacetic Acid on Asexual Embryogenesis in Vitro12

    Science.gov (United States)

    Tisserat, Brent; Murashige, Toshio

    1977-01-01

    Asexual embryogenesis in Daucus carota L. `Queen Anne's Lace' callus was suppressed by Ethephon, ethylene, and 2,4-dichlorophenoxyacetic acid (2,4-D). The Ethephon effect could be attributed to volatile and nonvolatile substances. The volatile component was probably entirely ethylene. Ethylene was liberated in the cultures in direct proportion to Ethephon added to the medium. Autoclaving of Ethephon caused a substantial decrease of measurable ethylene. Continuous exposure of callus to 5 μl/l ethylene depressed somatic cell embryogenesis, but not markedly. Depression of embryogenesis by 2,4-D was unrelated to ethylene evolution. PMID:16660109

  13. REVIEW OF WATER JET APPLICATIONS IN MANUFACTURING

    Directory of Open Access Journals (Sweden)

    Faruk MENDİ

    1999-02-01

    Full Text Available Usage of water jets in manufacturing processes, has been known for many decades. A wide range of engineering materials can be cut by water jets with satisfactory results. Enhanced reliability and efficiency of the technique, have yielded the technology greater interest for manufacturing applications. Water jets are used to cut soft materials such as wood, plastics, aluminium and copper. Abrasive water jets are used to cut very hard materials such as titanium, inconel, glass and ceramics. It is impossible to cut these materials with classical cutting technics. A water jet processing system utilises water pressure in the range of 100Mpa-400Mpa, for the different applications. In abrasive water jet milling and abrasive water jet cutting processes, the pressure of the jet is about 400Mpa. In water jet surface penning, the jet pressure is about 100Mpa. The process of abrasives mixing with the water stream is a complex phenomena. Erosion processes involved in cutting not yet fully understood. The lack of understanding the process call for other strategies in finding appropriate ways to obtain a precision depth in cutting operation. In this paper the principles of water jet systems had been explained. Results of experiments that made on cutting process and surface strengthening with water jet had been given.

  14. Monte Carlo Tools for Jet Quenching

    OpenAIRE

    Zapp, Korinna

    2011-01-01

    A thorough understanding of jet quenching on the basis of multi-particle final states and jet observables requires new theoretical tools. This talk summarises the status and propects of the theoretical description of jet quenching in terms of Monte Carlo generators.

  15. Understanding jets at the Large Hadron Collider

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, Matthew D. [Harvard Univ., Cambridge, MA (United States). Dept. of Physics

    2016-11-17

    Jet physics is an exciting and rapidly growing branch of particle physics, particularly relevant to the energy frontier. Just a few years ago, jets were universally treated as structureless objects, representing the momentum of an underlying quark or gluon. Nowadays, jets are understood to be intricate, dynamical objects with interesting hidden properties worthy of investigation and relevant for understanding quantum field theory.

  16. ECRH for JET: A feasibility study

    NARCIS (Netherlands)

    Lennholm, M.; Giruzzi, G.; Parkin, A.; Bouquey, F.; Braune, H.; Bruschi, A.; de la Luna, E.; Denisov, G.; Edlington, T.; Farina, D.; Farthing, J.; Figini, L.; Garavaglia, S.; Garcia, J.; Gerbaud, T.; Granucci, G.; Henderson, M.; Horton, L.; Kasparek, W.; Khilar, P.; Jennison, M.; Kirneva, N.; Kislov, D.; Kuyanov, A.; Litaudon, X.; Litvak, A. G.; Moro, A.; Nowak, S.; Parail, V.; Plaum, B.; Rimini, F.; Saibene, G.; Sips, A.; Sozzi, C.; Späh, P.; Trukhina, E.; Vaccaro, A.; Vdovin, V.

    2011-01-01

    For JET to fulfil its mission in preparing ITER operation, the installation of an electron cyclotron resonance heating system on JET would be desirable. The study described in this paper has investigated the feasibility of installing such a system on JET. The principal goals of such a system are: cu

  17. 基于二阶矩封闭湍流模型的非预混湍流火焰的数值模拟%Modelling of Turbulent Nonpremixed CH4/H2 Flame Using Second-Moment Turbulence Closure Models

    Institute of Scientific and Technical Information of China (English)

    李国岫

    2005-01-01

    Turbulent nonpremixed CH.J/H2 flame has been simulated using several typical differential second-moment turbulence closure (SMTC) models. To clarify the applicability of the various models, the LRR-IP model, JM model, SSG model as well as two modified LRR-IP models were tested. Some of above-mentioned SMTC models cannot provide the overall satisfactory predictions of this challenging case. It is confirmed again that the standard LRR-IP model considerably overpredict the centerline velocity decay rate, and therefore performs not well. Also it is interesting to observe that the JM model does not perform well in this challenging test case, although it has already been proved successful in other cases. The SSG model produces quite satisfactory prediction and performs equally well or better than the two modified LRR-IP models in the reacting case. It can be concluded that the modified LRR-IP models as well as the SSG model are superior to the other SMTC models in the turbulent nonpremixed CH4/H2 flame.

  18. Massive ethylene glycol poisoning triggers osmotic demyelination syndrome.

    Science.gov (United States)

    Ahmed, Azeemuddin; Tschetter, Paul A; Krasowski, Matthew D; Engelman, Amy

    2014-03-01

    Ethylene glycol is a toxic organic solvent implicated in thousands of accidental and intentional poisonings each year. Osmotic demyelination syndrome (ODS) is traditionally known as a complication of the rapid correction of hyponatremia. Our aim was to describe how patients with ethylene glycol toxicity may be at risk for developing ODS in the absence of hyponatremia. A 64-year old female patient was comatose upon presentation and laboratory results revealed an anion gap of 39, a plasma sodium of 150 mEq/L, a plasma potassium of 3.5 mEq/L, an osmolal gap of 218, an arterial blood gas pH of 7.02, whole blood lactate of 32 mEq/L, no measurable blood ethanol, and a plasma ethylene glycol concentration of 1055.5 mg/dL. The patient was treated for ethylene glycol poisoning with fomepizole and hemodialysis. Despite having elevated serum sodium levels, the patient's hospital course was complicated by ODS. Rapid changes in serum osmolality from ethylene glycol toxicity or its subsequent treatment can cause ODS independent of serum sodium levels. Copyright © 2014 Elsevier Inc. All rights reserved.

  19. Novel and existing data for a future physiological toxicokinetic model of ethylene and its metabolite ethylene oxide in mouse, rat, and human.

    Science.gov (United States)

    Filser, Johannes Georg; Artati, Anna; Li, Qiang; Pütz, Christian; Semder, Brigitte; Klein, Dominik; Kessler, Winfried

    2015-11-05

    The olefin ethylene is a ubiquitously found gas. It originates predominantly from plants, combustion processes and industrial sources. In mammals, inhaled ethylene is metabolized by cytochrome P450-dependent monooxygenases, particularly by cytochrome P450 2E1, to ethylene oxide, an epoxide that directly alkylates proteins and DNA. Ethylene oxide was mutagenic in vitro and in vivo in insects and mammals and carcinogenic in rats and mice. A physiological toxicokinetic model is a most useful tool for estimating the ethylene oxide burden in ethylene-exposed rodents and humans. The only published physiological toxicokinetic model for ethylene and metabolically produced ethylene oxide is discussed. Additionally, existing data required for the development of a future model and for testing its predictive accuracy are reviewed and extended by new gas uptake studies with ethylene and ethylene oxide in B6C3F1 mice and with ethylene in F344 rats. Copyright © 2015 The Authors. Published by Elsevier Ireland Ltd.. All rights reserved.

  20. Instabilities in Coaxial Rotating Jets

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The aim of this study is the characterization of the cylindrical mixing layer resulting layer resulting from the interaction of two coaxial swirling jets.The experimental part of this study was performed in a cylindrical water tunnel,permitting an independent rotation of two coaxial jets.The rotations are generated by means of 2×36 blades localized in two swirling chambers.As expected,the evolution of the main instabiltiy modes presents certain differences compared to the plane-mixing-layer case ,Experimental results obtained by tomography showed the existence of vortex rings and streamwise vortex paris in the near field region.This method also permitted the observation of the evolution and interaction of different modes.PIV velocity measurements realized in the meridian plans and the plans perpendicular to the jet axis show that rotation distrots the typical top-hat axial velocity profile.The transition of the the axial velocity profile from jet-like into wake-like is also observed.

  1. Laser Created Relativistic Positron Jets

    Energy Technology Data Exchange (ETDEWEB)

    Chen, H; Wilks, S C; Meyerhofer, D D; Bonlie, J; Chen, C D; Chen, S N; Courtois, C; Elberson, L; Gregori, G; Kruer, W; Landoas, O; Mithen, J; Murphy, C; Nilson, P; Price, D; Scheider, M; Shepherd, R; Stoeckl, C; Tabak, M; Tommasini, R; Beiersdorder, P

    2009-10-08

    Electron-positron jets with MeV temperature are thought to be present in a wide variety of astrophysical phenomena such as active galaxies, quasars, gamma ray bursts and black holes. They have now been created in the laboratory in a controlled fashion by irradiating a gold target with an intense picosecond duration laser pulse. About 10{sup 11} MeV positrons are emitted from the rear surface of the target in a 15 to 22-degree cone for a duration comparable to the laser pulse. These positron jets are quasi-monoenergetic (E/{delta}E {approx} 5) with peak energies controllable from 3-19 MeV. They have temperatures from 1-4 MeV in the beam frame in both the longitudinal and transverse directions. Positron production has been studied extensively in recent decades at low energies (sub-MeV) in areas related to surface science, positron emission tomography, basic antimatter science such as antihydrogen experiments, Bose-Einstein condensed positronium, and basic plasma physics. However, the experimental tools to produce very high temperature positrons and high-flux positron jets needed to simulate astrophysical positron conditions have so far been absent. The MeV temperature jets of positrons and electrons produced in our experiments offer a first step to evaluate the physics models used to explain some of the most energetic phenomena in the universe.

  2. Circular polarization in relativistic jets

    NARCIS (Netherlands)

    Macquart, JP

    2003-01-01

    Circular polarization is observed in some relativistic jet sources at radio wavelengths. It is largely associated with activity in the cores of the radio sources, is highly variable, and is strongest during ejection episodes. VLBI imaging and interstellar scintillation arguments show that the degree

  3. Breakup of diminutive Rayleigh jets

    CERN Document Server

    van Hoeve, Wim; Snoeijer, Jacco H; Versluis, Michel; Brenner, Michael P; Lohse, Detlef

    2010-01-01

    Discharging a liquid from a nozzle at sufficient large velocity leads to a continuous jet that due to capillary forces breaks up into droplets. Here we investigate the formation of microdroplets from the breakup of micron-sized jets with ultra high-speed imaging. The diminutive size of the jet implies a fast breakup time scale $\\tau_\\mathrm{c} = \\sqrt{\\rho r^3 / \\gamma}$ of the order of 100\\,ns{}, and requires imaging at 14 million frames per second. We directly compare these experiments with a numerical lubrication approximation model that incorporates inertia, surface tension, and viscosity [Eggers and Dupont, J. Fluid Mech. 262, 205 (1994); Shi, Brenner, and Nagel, Science 265, 219 (1994)]. The lubrication model allows to efficiently explore the parameter space to investigate the effect of jet velocity and liquid viscosity on the formation of satellite droplets. In the phase diagram we identify regions where the formation of satellite droplets is suppressed. We compare the shape of the droplet at pinch-off...

  4. Particle flow jets in the t anti t l+jets channel in ATLAS

    Energy Technology Data Exchange (ETDEWEB)

    Falke, Peter; Moles-Valls, Regina; Brock, Ian [Universitaet Bonn, Bonn (Germany)

    2016-07-01

    The ATLAS particle flow algorithm combines tracking and calorimeter information to achieve an improved resolution for jets and missing transverse momentum. Studies based on 8 TeV ATLAS data have shown improvements for the energy response and jet angular resolution. Additionally the pile-up contribution is considerably reduced. Jets stemming from b-quarks are important for top-quark and Higgs boson physics as well as for searches for new physics. Particle flow inherently adds tracker information to the jets and thus could allow improvements of the b-jet performance. This contribution presents the studies done using t anti t events in the l+jets channel at 13 TeV in ATLAS. The t anti t topology is advantageous, due to its clean signature and a large fraction of b-jets from the top-quark decays. The invariant mass distributions of the hadronically decaying W boson and top-quark are used to investigate the performance of particle flow jets in comparison to jets based only on calorimeter information. The calibration of the jet collection, which is the first step after the jet reconstruction, has been slightly modified for particle flow due to the different nature of the jets. A further emphasis is placed on properties of b-jets (e.g. the b-hadron decay mode and the decay multiplicity) within particle flow, which could allow the jet energy scale and jet energy resolution as well as b-tagging efficiencies to be further improved.

  5. Temporally Varying Ethylene Emission on Jupiter

    Science.gov (United States)

    Romani, Paul N.; Jennings, Donald E.; Bjoraker, Gordon L.; Sada, Pedro V.; McCabe. Geprge; Boyle, Robert J.

    2008-01-01

    Ethylene (C2H4) emission has been measured in the poles and equator of Jupiter. The 949 cm(sup -1) spectra were recorded with a high resolution spectrometer at the McMath-Pierce telescope at Kitt Peak in October-November 1998 and at the Infrared Telescope Facility at Mauna Kea in June 2000. C2H4 is an important product of methane chemistry in the outer planets. Knowledge of its abundance can help discriminate among the various proposed sets of CH4 photolysis branching ratios at Ly-alpha, and determine the relative importance of the reaction pathways that produce C2H2 and C2H6. In the equatorial region the C2H4 emission is weak, and we were only able to detect it at high air-mass, near the limb. We derive a peak equatorial molar abundance of C2H4 of 4.5 x 10(exp -7) - 1.7 x 10(exp -6) near 2.2 x 10(exp -3) mbar, with a total column of 5.7 x 10(exp 14) - 2.2 x 10(exp 15) molecules cm(exp -2) above 10 mbar depending upon choice of thermal profile. We observed enhanced C2H4 emission from the poles in the regions where auroras are seen in X-ray, UV, and near infrared images. In 2000 we measured a short-term change in the distribution of polar C2H4 emission; the emission in the north IR auroral "hot spot" decreased by a factor of three over a two-day interval. This transient its contribution peak at 5-10 microbar suggests that the polar e is primarily a thermal effect coupled with vertical transport. Comparing our observations from Kitt Peak and Mauna Kea shows that the C2H4 emission of the northern non-"hot spot" auroral regions did not change over the three-year period while that in the southern polar regions decreased.

  6. Assessment of a semi-quantitative screening method for diagnosis of ethylene glycol poisoning.

    Science.gov (United States)

    Sankaralingam, Arun; Thomas, Annette; James, David R; Wierzbicki, Anthony S

    2017-07-01

    Background Ethylene glycol poisoning remains a rare but important presentation to acute toxicology units. Guidelines recommended that ethylene glycol should be available as an 'urgent' test within 4 h, but these are difficult to deliver in practice. This study assessed a semi-quantitative enzymatic spectrophotometric assay for ethylene glycol compatible with automated platforms. Methods The ethylene glycol method was assessed in 21 samples from patients with an increased anion gap and metabolic acidosis not due to ethylene glycol ingestion, and seven samples known to contain ethylene glycol. All samples were analysed in random order in a blinded manner to their origin on a laboratory spectrophotometer. Results In this study, seven samples were known to contain ethylene glycol at concentrations >100 mg/L. The method correctly identified all seven samples as containing ethylene glycol. No false-positives were observed. Thirteen samples gave clear negative results. Ethylene glycol was present at ethylene glycol concentration against results obtained when the samples had been analysed using the quantitative method on an automated analyser showed a good correlation (R = 0.84) but with an apparent under-recovery. Conclusions A semi-quantitative assay for ethylene glycol was able to discriminate well between samples containing ethylene glycol and those with other causes of acidosis. It is a practical small-scale assay for rapid identification of cases of ethylene glycol poisoning.

  7. High selective ethane cracking to ethylene at Veba Oel plant

    Energy Technology Data Exchange (ETDEWEB)

    Sundaram, K.M. [ABB Lummus Crest, Bloomfield, NJ (United States); Albano, J.V. [ABB Lummus Crest, Bloomfield, NJ (United States); Goldmann, K. [Ruhr Oel GmbH, Muenchsmuenster (Germany)

    1995-03-01

    Thermal dehydrogenation is the only commercially feasible route to produce ethylene from ethane even today. Like many dehydrogenation reactions, this is also equilibrium limited under typical operating conditions. Factors such as feed impurities, operating conditions, reactor design and surface conditions influence the selectivity to ethylene. These are illustrated in the paper based on experimental data. Based on these results and through the use of rigorous kinetic models to describe the cracking furnace, a state of the art heater was built to crack ethane at Veba Oel. This furnace achieved high selectivity to ethylene ad long run lengths. The improvement in selectivity over conventional long residence time coils was significant and the deterioration of selectivity from start of run to end of run due to coke deposition in the new design was negligible. This heater also achieved long run lengths with high olefin contents in the ethane feed. (orig.)

  8. Structure and Mechanical Properties of Ethylene-butene Copolymers

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    The crystallinity of ethylene-butene copolymers prepared by copolymerization of ethylene and butene in the presence of a new highly active catalyst was studied by means of DSC, WAXD and DMA. The results show that the melting temperature, the crystallinity and the crystallite size decreased with increasing the content of butene in the copolymers. The copolymers have a high degree of branching, the butene segments are mainly in the amorphous regions of the copolymers, while the polyethylene sequence forms crystal phase acting as crosslinking bondage between the molecules at room temperature. The ethylene-butene copolymers have a low modulus, a low stress and a high strain analogous to the stress-strain behavior of non-cross thermoplastic elastomer.

  9. COMPOSITIONAL HETEROGENEITY OF ETHYLENE OXIDE-BUTYLENE TEREPHTHALATE SEGMENTED COPOLYMER

    Institute of Scientific and Technical Information of China (English)

    De-zhu Ma; Dong-sheng Li; Ming-chuan Zhao; Mo-zhen Wang; Ran Ye; Xiao-lie Luo

    1999-01-01

    A series of ethylene oxide-butylene terephthalate (EOBT) segmented copolymers with different soft segment length and hard segment content were synthesized. The compositional heterogeneity was studied by solvent extraction. The results show that the compositional heterogeneity increases when soft segment length and hard segment content increase. The compositional heterogeneity is also reflected in the crystallization behavior and morphology of soft and hard segment in EOBT segmented copolymer. The more compositional heterogeneous the EOBT segmented copolymer is, the more different the morphology and the crystallization behavior between separated fractions. Compared with ethylene oxide-ethylene terephthalate (EOET) segmented copolymer, compositional heterogeneity in EOBT segmented copolymer is weaker. But the compositional heterogeneity in EOBT segmented copolymer with long soft segment and high hard segment content is still obvious.

  10. Jets in Heavy Ion Collisions with CMS

    CERN Document Server

    Salur, Sevil

    2016-01-01

    Jet physics in heavy ion collisions is a rich field which has been rapidly evolving since the first observations of medium interactions at RHIC through back-to-back hadron correlations and at LHC via reconstructed jets. In order to completely characterize the final state via jet-medium interactions and distinguish between competing energy loss mechanisms complementary and robust jet observables are investigated. Latest developments of jet finding techniques and their applications to heavy ion environments are discussed with an emphasis given on experimental results from CMS experiment.

  11. The Structure and Dynamics of GRB Jets

    Energy Technology Data Exchange (ETDEWEB)

    Granot, Jonathan; /KIPAC, Menlo Park

    2006-10-25

    There are several lines of evidence which suggest that the relativistic outflows in gamma-ray bursts (GRBs) are collimated into narrow jets. The jet structure has important implications for the true energy release and the event rate of GRBs, and can constrain the mechanism responsible for the acceleration and collimation of the jet. Nevertheless, the jet structure and its dynamics as it sweeps up the external medium and decelerates, are not well understood. In this review I discuss our current understanding of GRB jets, stressing their structure and dynamics.

  12. Reducing Coal Dust With Water Jets

    Science.gov (United States)

    Gangal, M. D.; Lewis, E. V.

    1985-01-01

    Jets also cool and clean cutting equipment. Modular pick-and-bucket miner suffers from disadvantage: Creates large quantities of potentially explosive coal dust. Dust clogs drive chain and other parts and must be removed by hand. Picks and bucket lips become overheated by friction and be resharpened or replaced frequently. Addition of oscillating and rotating water jets to pick-and-bucket machine keeps down dust, cools cutting edges, and flushes machine. Rotating jets wash dust away from drive chain. Oscillating jets cool cutting surfaces. Both types of jet wet airborne coal dust; it precipitates.

  13. Raman Spectra of Methane, Ethylene, Ethane, Dimethyl ether, Formaldehyde and Propane for Combustion Applications

    KAUST Repository

    Magnotti, G.

    2015-05-09

    Spontaneous Raman scattering measurements of temperature and major species concentration in hydrocarbon-air flames require detailed knowledge of the Raman spectra of the hydrocarbons present when fuels more complex than methane are used. Although hydrocarbon spectra have been extensively studied at room temperature, there are no data available at higher temperatures. Quantum mechanical calculations, when available are not sufficiently accurate for combustion applications. This work presents experimental measurements of spontaneous Stokes-Raman scattering spectra of methane, ethylene, ethane, dimethyl ether, formaldehyde and propane in the temperature range 300-860 K. Raman spectra from heated hydrocarbons jets have been collected with a higher resolution than is generally employed for Raman measurements in combustion applications. A set of synthetic spectra have been generated for each hydrocarbon, providing the basis for extrapolation to higher temperatures. The spectra provided here will enable simultaneous measurements of multiple hydrocarbons in flames. This capability will greatly extend the range of applicability of Raman measurements in combustion applications. In addition, the experimental spectra provide a validation dataset for quantum mechanical models.

  14. Influence of ethylene glycol pretreatment on effectiveness of atmospheric pressure plasma treatment of polyethylene fibers

    Energy Technology Data Exchange (ETDEWEB)

    Wen Ying; Li Ranxing [Key Laboratory of Textile Science and Technology (Donghua University), Ministry of Education (China); Cai Fang [Key Laboratory of Eco-Textiles (Donghua University), Ministry of Education (China); Fu Kun; Peng Shujing; Jiang Qiuran; Yao Lan [Key Laboratory of Textile Science and Technology (Donghua University), Ministry of Education (China); Qiu Yiping, E-mail: ypqiu@dhu.edu.cn [Department of Textile Materials Science and Product Design, College of Textiles, Donghua University, Shanghai 201620 (China)

    2010-03-01

    For atmospheric pressure plasma treatments, the results of plasma treatments may be influenced by liquids adsorbed into the substrate. This paper studies the influence of ethylene glycol (EG) pretreatment on the effectiveness of atmospheric plasma jet (APPJ) treatment of ultrahigh molecular weight polyethylene (UHMWPE) fibers with 0.31% and 0.42% weight gain after soaked in EG/water solution with concentration of 0.15 and 0.3 mol/l for 24 h, respectively. Scanning electron microscopy (SEM) shows that the surface of fibers pretreated with EG/water solution does not have observable difference from that of the control group. The X-ray photoelectron spectroscopy (XPS) results show that the oxygen concentration on the surface of EG-pretreated fibers is increased less than the plasma directly treated fibers. The interfacial shear strength (IFSS) of plasma directly treated fibers to epoxy is increased almost 3 times compared with the control group while that of EG-pretreated fibers to epoxy does not change except for the fibers pretreated with lower EG concentration and longer plasma treatment time. EG pretreatment reduces the water contact angle of UHMWPE fibers. In conclusion, EG pretreatment can hamper the effect of plasma treatment of UHMWPE fibers and therefore longer plasma treatment duration is required for fibers pretreated with EG.

  15. Transcriptional Regulation of the Ethylene Response Factor LeERF2 in the Expression of Ethylene Biosynthesis Genes Controls Ethylene Production in Tomato and Tobacco1[W][OA

    Science.gov (United States)

    Zhang, Zhijin; Zhang, Haiwen; Quan, Ruidan; Wang, Xue-Chen; Huang, Rongfeng

    2009-01-01

    Fine-tuning of ethylene production plays an important role in developmental processes and in plant responses to stress, but very little is known about the regulation of ethylene response factor (ERF) proteins in ethylene biosynthesis genes and ethylene production. Identifying cis-acting elements and transcription factors that play a role in this process, therefore, is important. Previously, a tomato (Solanum lycopersicum [f. sp. Lycopersicon esculentum]) ERF protein, LeERF2, an allele of TERF2, was reported to confer ethylene triple response on plants. This paper reports the transcriptional modulation of LeERF2/TERF2 in ethylene biosynthesis in tomato and tobacco (Nicotiana tabacum). Using overexpressing and antisense LeERF2/TERF2 transgenic tomato, we found that LeERF2/TERF2 is an important regulator in the expression of ethylene biosynthesis genes and the production of ethylene. Expression analysis revealed that LeERF2/TERF2 is ethylene inducible, and ethylene production stimulated by ethylene was suppressed in antisense LeERF2/TERF2 transgenic tomato, indicating LeERF2/TERF2 to be a positive regulator in the feedback loop of ethylene induction. Further research showed that LeERF2/TERF2 conservatively modulates ethylene biosynthesis in tobacco and that such regulation in tobacco is associated with the elongation of the hypocotyl and insensitivity to abscisic acid and glucose during germination and seedling development. The effects on ethylene synthesis were similar to those of another ERF protein, TERF1, because TERF1 and LeERF2/TERF2 have overlapping roles in the transcriptional regulation of ethylene biosynthesis in tobacco. Biochemical analysis showed that LeERF2/TERF2 interacted with GCC box in the promoter of NtACS3 and with dehydration-responsive element in the promoter of LeACO3, resulting in transcriptional activation of the genes for ethylene biosynthesis in tomato and tobacco, which is a novel regulatory function of ERF proteins in plant ethylene

  16. Ejector Noise Suppression with Auxiliary Jet Injection

    Science.gov (United States)

    Berman, Charles H.; Andersen, Otto P., Jr.

    1997-01-01

    An experimental program to reduce aircraft jet turbulence noise investigated the interaction of small auxiliary jets with a larger main jet. Significant reductions in the far field jet noise were obtained over a range of auxiliary jet pressures and flow rates when used in conjunction with an acoustically lined ejector. While the concept is similar to that of conventional ejector suppressors that use mechanical mixing devices, the present approach should improve thrust and lead to lower weight and less complex noise suppression systems since no hardware needs to be located in the main jet flow. A variety of auxiliary jet and ejector configurations and operating conditions were studied. The best conditions tested produced peak to peak noise reductions ranging from 11 to 16 dB, depending on measurement angle, for auxiliary jet mass flows that were 6.6% of the main jet flow with ejectors that were 8 times the main jet diameter in length. Much larger reductions in noise were found at the original peak frequencies of the unsuppressed jet over a range of far field measurement angles.

  17. [Tunable diode laser absorption spectroscopy system for trace ethylene detection].

    Science.gov (United States)

    Pan, Wei-Dong; Zhang, Jia-Wei; Dai, Jing-Min; Song, Kai

    2012-10-01

    Tunable diode laser absorption spectroscopy (TDLAS) was characterized by ultra-narrow line width laser and wavelength modulation, which makes it possible to scan a single absorption line. TDLAS has an advantage in trace gas analysis for its high resolution, high sensitivity and quick response. The 1 626.8 nm absorption line of ethylene was selected for detecting by analyzing its absorption line characteristic. The TDLAS system was developed with a white type multi-pass cell, combined with wavelength modulation and harmonic detection. Ethylene concentration ranges from 20 to 1 200 ppmv were tested using this system. The estimated detection limit of the system is 10 ppmv.

  18. Two Types of Magnetohydrodynamic Sheath Jets

    CERN Document Server

    Kaburaki, Osamu

    2009-01-01

    Recent observations of astrophysical jets emanating from various galactic nuclei strongly suggest that a double layered structure, or a spine-sheath structure, is likely to be their common feature. We propose that such a sheath jet structure can be formed magnetohydrodynamically within a valley of the magnetic pressures, which is formed between the peaks due to the poloidal and toroidal components, with the centrifugal force acting on the rotating sheath plasma is balanced by the hoop stress of the toroidal field. The poloidal field concentrated near the polar axis is maintained by a converging plasma flow toward the jet region, and the toroidal field is developed outside the jet cone owing to the poloidal current circulating through the jet. Under such situations, the set of magnetohydrodynamic (MHD) equations allows two main types of solutions, at least, in the region far from the footpoint. The first type solution describes the jets of marginally bound nature. This type is realized when the jet temperature...

  19. Nonstationary photonic jet from dielectric microsphere

    CERN Document Server

    Geints, Yu; Zemlyanov, A

    2014-01-01

    A photonic jet commonly denotes the specific spatially localized region in the near-field forward scattering of a light wave at a dielectric micron-sized particle. We present the detailed calculations of the transient response of an airborne silica microsphere illuminated by a femtosecond laser pulse. The spatial area constituting the photonic jet is theoretically investigated and the temporal dynamics of jet dimensions as well as of jet peak intensity is analyzed. The role of morphology-dependent resonances in jet formation is highlighted. The evolution scenario of a nonstationary photonic jet generally consists of the non-resonant and resonant temporal phases. In every phase, the photonic jet can change its spatial form and intensity.

  20. NLO Jet Physics with BlackHat

    Energy Technology Data Exchange (ETDEWEB)

    Berger, C.F.; /MIT, LNS; Bern, Z.; /UCLA; Dixon, L.J.; /SLAC; Cordero, F.Febres; /Simon Bolivar U.; Forde, D.; /CERN /NIKHEF, Amsterdam; Gleisberg, T.; /SLAC; Ita, H.; /UCLA; Kosower, D.A.; /DAPNIA, Saclay; Maitre, D.; /Durham U.

    2010-02-15

    We present several results obtained using the BLACKHAT next-to-leading order QCD program library, in conjunction with SHERPA. In particular, we present distributions for vector boson plus 1,2,3-jet production at the Tevatron and at the asymptotic running energy of the Large Hadron Collider, including new Z + 3-jet distributions. The Z + 2-jet predictions for the second-jet P{sub T} distribution are compared to CDF data. We present the jet-emission probability at NLO in W + 2-jet events at the LHC, where the tagging jets are taken to be the ones furthest apart in pseudorapidity. We analyze further the large left-handed W{sup {+-}} polarization, identified in our previous study, for W bosons produced at high P{sub T} at the LHC.

  1. Relativistic AGN jets - II. Jet properties and mixing effects for episodic jet activity

    NARCIS (Netherlands)

    Walg, S.; Achterberg, A.; Markoff, S.; Keppens, R.; Porth, O.

    2014-01-01

    Various radio galaxies show signs of having gone through episodic jet outbursts in the past. An example is the class of double-double radio galaxies (DDRGs). However, to follow the evolution of an individual source in real-time is impossible due to the large time-scales involved. Numerical studies p

  2. Ethylene Control of Fruit Ripening: Revisiting the Complex Network of Transcriptional Regulation.

    Science.gov (United States)

    Liu, Mingchun; Pirrello, Julien; Chervin, Christian; Roustan, Jean-Paul; Bouzayen, Mondher

    2015-12-01

    The plant hormone ethylene plays a key role in climacteric fruit ripening. Studies on components of ethylene signaling have revealed a linear transduction pathway leading to the activation of ethylene response factors. However, the means by which ethylene selects the ripening-related genes and interacts with other signaling pathways to regulate the ripening process are still to be elucidated. Using tomato (Solanum lycopersicum) as a reference species, the present review aims to revisit the mechanisms by which ethylene regulates fruit ripening by taking advantage of new tools available to perform in silico studies at the genome-wide scale, leading to a global view on the expression pattern of ethylene biosynthesis and response genes throughout ripening. Overall, it provides new insights on the transcriptional network by which this hormone coordinates the ripening process and emphasizes the interplay between ethylene and ripening-associated developmental factors and the link between epigenetic regulation and ethylene during fruit ripening.

  3. Numerical Study on Laminar Burning Velocity and Flame Stability of Premixed Methane/Ethylene/Air Flames

    Institute of Scientific and Technical Information of China (English)

    陈珊珊; 蒋勇; 邱榕; 安江涛

    2012-01-01

    A numerical study on premixed methane/ethylene/air flames with various ethylene fractions and equivalence ratios was conducted at room temperature and atmospheric pressure. The effects of ethylene addition on laminar burning velocity, flame structure and flame stability under the condition of lean burning were investigated. The results show that the laminar burning velocity increases with ethylene fraction, especially at a large equivalence ratio. More ethylene addition gives rise to higher concentrations of H, O and OH radicals in the flame, which significantly promotes chemical reactions, and a linear correlation exists between the laminar burning velocity and the maximum H + OH concentration in the reaction zone. With the increase of ethylene fraction, the adiabatic flame temperature is raised, while the inner layer temperature becomes lower, contributing to the enhancement of combustion. Markstein length and Markstein number, representative of the flame stability, increase as more ethylene is added, indicating the tendency of flame stability to improve with ethylene addition.

  4. Syntheses of Poly(ethylene oxide) Macromonomers Carrying Tertiary Amine and Quaternary Ammonium End Groups

    National Research Council Canada - National Science Library

    Senyo, Takamichi; Atago, Yuji; Liang, Huanan; Shen, Renhua; Ito, Koichi

    2003-01-01

    p-Vinylbenzyl alcohol, partially alkoxidated with potassium naphthalene, was used successfully to initiate living polymerization of ethylene oxide to afford α-p-vinylbenzyl-ω-hydroxy poly(ethylene oxide) (PEO) macromonomers. The ω...

  5. Experiment and Simulation of Autoignition in Jet Flames and its Relevance to Flame Stabilization and Structure

    KAUST Repository

    Al-Noman, Saeed M.

    2016-06-01

    mainly between the fuel nozzle and the lifted flame edge. On the other hand, they were formed just prior to the flame edge for the non-autoignited lifted flames. The effect of fuel pyrolysis and partial oxidation were found to be important in explaining autoignited liftoff heights, especially in the Mild combustion regime. Flame structures of autoignited flames were investigated numerically for syngas (CO/H2) and methane fuels. The simulations of syngas fuel accounting for the differential diffusion have been performed by adopting several kinetic mechanisms to test the models ability in predicting the flame behaviors observed previously. The results agreed well with the observed nozzle-attached flame characteristics in case of non-autoignited flames. For autoignited lifted flames in high temperature regime, a unique autoignition behavior can be predicted having HO2 and H2O2 radicals in a broad region between the nozzle and stabilized lifted flame edge. Autoignition characteristics of laminar nonpremixed methane jet flames in high- temperature coflow air were studied numerically. Several flame configurations were investigated by varying the initial temperature and fuel mole fraction. Characteristics of chemical kinetics structures for autoignited lifted flames were discussed based on the kinetic structures of homogeneous autoignition and flame propagation of premixed mixtures. Results showed that for autoignited lifted flame with tribrachial structure, a transition from autoignition to flame propagation modes occurs for reasonably stoichiometric mixtures. Characteristics of Mild combustion can be treated as an autoignited lean premixed lifted flame. Transition behavior from Mild combustion to a nozzle-attached flame was also investigated by increasing the fuel mole fraction.

  6. Effect of Comonomer Ethylene on Plateau Modulus of Crystalline Ethylene-propylene Random Copolymer with Broad Molecular Weight Distribution

    Institute of Scientific and Technical Information of China (English)

    丁健; 徐日炜; 丁雪佳; 余鼎声

    2005-01-01

    Ethylene-propylene random copolymer with ultra-high molecular weight (UHPPR) and broad molecular weight distribution (MWD) was prepared with Ziegler-Natta catalyst. The viscoelastic behavior of UHPPR has been investigated by means of oscillatory rheometer at 180, 200 and 220℃. The loss modulus (G"""") curves of 180 and 200℃ present a pronounced maximum at 38.10 and 84.70r/s, respectively, For the first time, this makes it possible to directly determine the plateau modulus ( GN0 ) of crystalline ethylene-propylene random copolymer with broad MWD in a certain experimental temperature G""""(w) curve. The plateau modulus of UHPPR is 4.51×105 and 3.67×105 Paat 180 and 200℃ respectively, increasing with random incorporation of comonomer ethylene into the molecular chains and being independent of molecular weight.

  7. Jet Dipolarity: Top Tagging with Color Flow

    Energy Technology Data Exchange (ETDEWEB)

    Hook, Anson; Jankowiak, Martin; /SLAC /Stanford U., Phys. Dept.; Wacker, Jay G.; /SLAC

    2011-08-12

    A new jet observable, dipolarity, is introduced that can distinguish whether a pair of subjets arises from a color singlet source. This observable is incorporated into the HEPTopTagger and is shown to improve discrimination between top jets and QCD jets for moderate to high p{sub T}. The impressive resolution of the ATLAS and CMS detectors means that a typical QCD jet at the LHC deposits energy in {Omicron}(10-100) calorimeter cells. Such fine-grained calorimetry allows for jets to be studied in much greater detail than previously, with sophisticated versions of current techniques making it possible to measure more than just the bulk properties of jets (e.g. event jet multiplicities or jet masses). One goal of the LHC is to employ these techniques to extend the amount of information available from each jet, allowing for a broader probe of the properties of QCD. The past several years have seen significant progress in developing such jet substructure techniques. A number of general purpose tools have been developed, including: (i) top-tagging algorithms designed for use at both lower and higher p{sub T} as well as (ii) jet grooming techniques such as filtering, pruning, and trimming, which are designed to improve jet mass resolution. Jet substructure techniques have also been studied in the context of specific particle searches, where they have been shown to substantially extend the reach of traditional search techniques in a wide variety of scenarios, including for example boosted Higgses, neutral spin-one resonances, searches for supersymmetry, and many others. Despite these many successes, however, there is every reason to expect that there remains room for refinement of jet substructure techniques.

  8. Performance of large-R jets and jet substructure reconstruction with the ATLAS detector

    CERN Document Server

    The ATLAS collaboration

    2012-01-01

    This paper presents the application of techniques to study jet substructure. The performance of modified jet algorithms for a variety of jet types and event topologies is investigated. Properties of jets subjected to the mass-drop filtering, trimming and pruning algorithms are found to have a reduced sensitivity to multiple proton-proton interactions and exhibit improved stability at high luminosity. Monte Carlo studies of the signal-background discrimination with jet grooming in new physics searches based on jet invariant mass and jet substructure properties are also presented. The application of jet trimming is shown to improve the robustness of large-R jet measurements, reduce sensitivity to the superfluous effects due to the intense environment of the high luminosity LHC, and improve the physics potential of searches for heavy boosted objects. The analyses presented in this note use the full 2011 ATLAS dataset, corresponding to an integrated luminosity of 4.7 \\pm 0.2 fb−1 .

  9. The tomato ethylene receptors NR and LeETR4 are negative regulators of ethylene response and exhibit functional compensation within a multigene family.

    Science.gov (United States)

    Tieman, D M; Taylor, M G; Ciardi, J A; Klee, H J

    2000-05-09

    The plant hormone ethylene is involved in many developmental processes, including fruit ripening, abscission, senescence, and leaf epinasty. Tomato contains a family of ethylene receptors, designated LeETR1, LeETR2, NR, LeETR4, and LeETR5, with homology to the Arabidopsis ETR1 ethylene receptor. Transgenic plants with reduced LeETR4 gene expression display multiple symptoms of extreme ethylene sensitivity, including severe epinasty, enhanced flower senescence, and accelerated fruit ripening. Therefore, LeETR4 is a negative regulator of ethylene responses. Reduced expression of this single gene affects multiple developmental processes in tomato, whereas in Arabidopsis multiple ethylene receptors must be inactivated to increase ethylene response. Transgenic lines with reduced NR mRNA levels exhibit normal ethylene sensitivity but elevated levels of LeETR4 mRNA, indicating a functional compensation of LeETR4 for reduced NR expression. Overexpression of NR in lines with lowered LeETR4 gene expression eliminates the ethylene-sensitive phenotype, indicating that despite marked differences in structure these ethylene receptors are functionally redundant.

  10. Maize and Arabidopsis ARGOS Proteins Interact with Ethylene Receptor Signaling Complex, Supporting a Regulatory Role for ARGOS in Ethylene Signal Transduction[OPEN

    Science.gov (United States)

    Shi, Jinrui; Wang, Hongyu; Habben, Jeffrey E.

    2016-01-01

    The phytohormone ethylene regulates plant growth and development as well as plant response to environmental cues. ARGOS genes reduce plant sensitivity to ethylene when overexpressed in transgenic Arabidopsis (Arabidopsis thaliana) and maize (Zea mays). A previous genetic study suggested that the endoplasmic reticulum and Golgi-localized maize ARGOS1 targets the ethylene signal transduction components at or upstream of CONSTITUTIVE TRIPLE RESPONSE1, but the mechanism of ARGOS modulating ethylene signaling is unknown. Here, we demonstrate in Arabidopsis that ZmARGOS1, as well as the Arabidopsis ARGOS homolog ORGAN SIZE RELATED1, physically interacts with Arabidopsis REVERSION-TO-ETHYLENE SENSITIVITY1 (RTE1), an ethylene receptor interacting protein that regulates the activity of ETHYLENE RESPONSE1. The protein-protein interaction was also detected with the yeast split-ubiquitin two-hybrid system. Using the same yeast assay, we found that maize RTE1 homolog REVERSION-TO-ETHYLENE SENSITIVITY1 LIKE4 (ZmRTL4) and ZmRTL2 also interact with maize and Arabidopsis ARGOS proteins. Like AtRTE1 in Arabidopsis, ZmRTL4 and ZmRTL2 reduce ethylene responses when overexpressed in maize, indicating a similar mechanism for ARGOS regulating ethylene signaling in maize. A polypeptide fragment derived from ZmARGOS8, consisting of a Pro-rich motif flanked by two transmembrane helices that are conserved among members of the ARGOS family, can interact with AtRTE1 and maize RTL proteins in Arabidopsis. The conserved domain is necessary and sufficient to reduce ethylene sensitivity in Arabidopsis and maize. Overall, these results suggest a physical association between ARGOS and the ethylene receptor signaling complex via AtRTE1 and maize RTL proteins, supporting a role for ARGOS in regulating ethylene perception and the early steps of signal transduction in Arabidopsis and maize. PMID:27268962

  11. Periodic jetting and monodisperse jet drops from oblique gas injection

    Science.gov (United States)

    McRae, Oliver; Gaillard, Antoine; Bird, James C.

    2017-07-01

    When air is blown in a straw or tube near an air-liquid interface, typically one of two behaviors is observed: a dimple in the liquid's surface, or a frenzy of sputtering bubbles, waves, and spray. Here we report and characterize an intermediate regime that can develop when a confined air jet enters the interface at an angle. This regime is oscillatory with a distinct characteristic frequency and can develop periodic angled jets that can break up into monodisperse aerosols. The underlying mechanisms responsible for this highly periodic regime are not well understood. Here we flow a continuous stream of gas through a tube near a liquid surface, observing both optically and acoustically the deformation of the liquid-air interface as various parameters are systematically adjusted. We show that the Kelvin-Helmholtz instability is responsible for the inception of waves within a cavity formed by the gas. Inertia, gravity, and capillary forces both shape the cavity and govern the frequency and amplitude of these gas-induced cavity waves. The flapping cavity focuses the waves into a series of periodic jets that can break up into droplets following the Rayleigh-Plateau instability. We present scaling arguments to rationalize the fundamental frequencies driving this system, as well as the conditions that bound the periodic regime. These frequencies and conditions compare well with our experimental results.

  12. Interaction of a hot jet with two cold side jets

    Directory of Open Access Journals (Sweden)

    Nouali Nassira

    2015-01-01

    Full Text Available Spreading of the multijet in terms of both the velocity and temperature field depends strongly on the flow type related to the velocity and temperature ratios between the cold side jets to the hot central one. This is the reason why the present work focuses on numerical investigation of non isothermal three parallel non-ventilated turbulent plane jets. As well, it seems natural to pick as reference the available experimental data. The numerical predictions confirm the three types (A, B, C of flow patterns given by the available flow visualization and reveal a fourth that will be called type D. The purpose of the present study is to explore the effect of the velocity ratio on the decay rates of the velocity and temperature in the fully developed region. It is found that the addition of side jets increase the rate of decrease of the centerline velocity for the flow of type A and decreases in the other cases. The effect of various types of flow on the rate of decrease of the velocity and the temperature in the fully developed flow region are investigated in details: This led to establish several correlations of the rate of decrease that play an important role in the diffusion of momentum and temperature.

  13. Synthesis of Titanium Dioxide Nanoparticles Using a Double-Slit Curved Wall-Jet Burner

    KAUST Repository

    Ismail, Mohamed

    2016-05-04

    A novel double-slit curved wall-jet (DS-CWJ) burner was proposed and utilized for flame synthesis. This burner was comprised of double curved wall-jet nozzles with coaxial slits; the inner slit was for the delivery of titanium tetraisopropoxide (TTIP) precursor while the outer one was to supply premixed fuel/air mixture of ethylene (C2H4) or propane (C3H8). This configuration enabled rapid mixing between the precursor and reactants along the curved surface and inside the recirculation zone of the burner. Particle growth of titanium dioxide (TiO2) nanoparticles and their phases was investigated with varying equivalence ratio and Reynolds number. Flow field and flame structure were measured using particle image velocimetry (PIV) and OH planar laser-induced fluorescence (PLIF) techniques, respectively. The nanoparticles were characterized using high-resolution transmission electron microscopy (HRTEM), X-ray diffraction (XRD), and nitrogen adsorption Brunauer–Emmett–Teller (BET) for surface area analysis. The flow field consisted of a wall-jet region leading to a recirculation zone, an interaction jet region, followed by a merged-jet region. The DS-CWJ burner revealed appreciable mixing characteristics between the precursor and combustion gases near the nozzle regions, with a slight increase in the axial velocity due to the precursor injection. The precursor supply had a negligible effect on the flame structure. The burner produced a reasonably uniform size (13–18 nm) nanoparticles with a high BET surface area (>100 m2/g). The phase of TiO2 nanoparticles was mainly dependent on the equivalence ratio and fuel type, which impact flame height, heat release rate, and high temperature residence time of the precursor vapor. For ethylene flames, the anatase content increased with the equivalence ratio, whereas it decreased in the case of propane flames. The synthesized TiO2 nanoparticles exhibited high crystallinity and the anatase phase was dominant at high equivalence

  14. 78 FR 24738 - Ethylene Oxide; Receipt of Application for Emergency Exemption, Solicitation of Public Comment

    Science.gov (United States)

    2013-04-26

    ... AGENCY Ethylene Oxide; Receipt of Application for Emergency Exemption, Solicitation of Public Comment... Service (APHIS) to use the pesticide ethylene oxide (CAS No. 75-21-8) to sterilize the interior surfaces... APHIS has requested the EPA Administrator to issue a quarantine exemption for the use of ethylene oxide...

  15. 46 CFR 154.1730 - Ethylene oxide: Loading and off loading.

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Ethylene oxide: Loading and off loading. 154.1730... Operating Requirements § 154.1730 Ethylene oxide: Loading and off loading. (a) The master shall ensure that before ethylene oxide is loaded into a cargo tank: (1) The tank is thoroughly clean, dry, and free of...

  16. 21 CFR 172.808 - Copolymer condensates of ethylene oxide and propylene oxide.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Copolymer condensates of ethylene oxide and propylene oxide. 172.808 Section 172.808 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH... ethylene oxide and propylene oxide. Copolymer condensates of ethylene oxide and propylene oxide may be...

  17. 78 FR 46260 - Sorbitan Monooleate Ethylene Oxide Adduct; Exemption From the Requirement of a Tolerance

    Science.gov (United States)

    2013-07-31

    ... AGENCY 40 CFR Part 180 Sorbitan Monooleate Ethylene Oxide Adduct; Exemption From the Requirement of a... ethylene oxide adduct'' and as ``polysorbate 80'') when used as an inert ingredient in antimicrobial... residues of sorbitan monooleate ethylene oxide adduct. DATES: This regulation is effective July 31, 2013...

  18. 40 CFR 180.1040 - Ethylene glycol; exemption from the requirement of a tolerance.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 23 2010-07-01 2010-07-01 false Ethylene glycol; exemption from the... Exemptions From Tolerances § 180.1040 Ethylene glycol; exemption from the requirement of a tolerance. Ethylene glycol as a component of pesticide formulations is exempt from the requirement of a tolerance when...

  19. 21 CFR 177.1315 - Ethylene-1, 4-cyclohexylene dimethylene terephthalate copolymers.

    Science.gov (United States)

    2010-04-01

    ... production or added to impart desired physical or technical properties. (b) Specifications: Ethylene-1,4... ethylene glycol and 1 to 15 mole percent of 1,4-cyclohexane-di-methanol (70 percent trans isomer, 30... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene-1, 4-cyclohexylene dimethylene...

  20. Genome Wide Identification and Expression Profiling of Ethylene Receptor Genes during Soybean Nodulation.

    Science.gov (United States)

    Wang, Youning; Yuan, Jinhong; Yang, Wei; Zhu, Lin; Su, Chao; Wang, Xiaodi; Wu, Haiyan; Sun, Zhengxi; Li, Xia

    2017-01-01

    It has long been known that the gaseous plant hormone ethylene plays a key role in nodulation in legumes. The perception of ethylene by a family of five membrane-localized receptors is necessary to trigger the ethylene signaling pathway, which regulates various biological responses in Arabidopsis. However, a systematic analysis of the ethylene receptors in leguminous plants and their roles in nodule development is lacking. In this study, we performed a characterization of ethylene receptor genes based on the latest Glycine max genome sequence and a public microarray database. Eleven ethylene receptor family genes were identified in soybean through homology searches, and they were divided into two subgroups. Exon-intron analysis showed that the gene structures are highly conserved within each group. Further analysis of their expression patterns showed that these ethylene receptor genes are differentially expressed in various soybean tissues and organs, including functional nodules. Notably, the ethylene receptor genes showed different responses to rhizobial infection and Nod factors, suggesting a possible role for ethylene receptors and ethylene signaling in rhizobia-host cell interactions and nodulation in soybean. Together, these data indicate the functional divergence of ethylene receptor genes in soybean, and that some of these receptors mediate nodulation, including rhizobial infection, nodule development, and nodule functionality. These findings provide a foundation for further elucidation of the molecular mechanism by which the ethylene signaling pathway regulates nodulation in soybean, as well as other legumes.

  1. 21 CFR 177.1360 - Ethylene-vinyl acetate-vinyl alcohol copolymers.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Ethylene-vinyl acetate-vinyl alcohol copolymers... acetate-vinyl alcohol copolymers. Ethylene-vinyl acetate-vinyl alcohol copolymers (CAS Reg. No. 26221-27-2... accordance with the following prescribed conditions: (a) Ethylene-vinyl acetate-vinyl alcohol copolymers...

  2. Partonic energy loss in ultrarelativistic heavy ion collisions jet suppression versus jet fragmentation softening

    CERN Document Server

    Lokhtin, Igor P

    2003-01-01

    We discuss the modification of a jet fragmentation function due to medium-induced partonic energy loss in context of leading particle observables in ultrarelativistic nucleus-nucleus interactions. We also analyze the relation between in-medium softening jet fragmentation function and suppression of the jet rates due to energy loss outside the jet cone. The predicted anti-correlation between two effects allows to probe a fraction of partonic energy loss carried out of the jet cone and truly lost to the jet.

  3. Blow-off characteristics of turbulent premixed flames in curved-wall Jet Burner

    KAUST Repository

    Mansour, Morkous S.

    2015-08-02

    This study concerns the flame dynamics of a curved-wall jet (CWJ) stabilized turbulent premixed flame as it approaches blow-off conditions. Time resolved OH planar laser-induced fluorescence (PLIF) delineated reaction zone contours and simultaneously stereoscopic particle image velocimetry (SPIV) quantified the turbulent flow field features. Ethylene/air flames were stabilized in CWJ burner to determine the sequence of events leading to blowoff. For stably burning flames far from blowoff, flames are characterized with a recirculation zone (RZ) upstream for flame stabilization followed by an intense turbulent interaction jet (IJ) and merged-jet regions downstream; the flame front counterparts the shear layer vortices. Near blowoff, as the velocity of reactants increases, high local stretch rates exceed the extinction stretch rates instantaneously resulting in localized flame extinction along the IJ region. As Reynolds number (Re) increases, flames become shorter and are entrained by larger amounts of cold reactants. The increased strain rates together with heat loss effects result in further fragmentation of the flame, eventually leading to the complete quenching of the flame. This is explained in terms of local turbulent Karlovitz stretch factor (K) and principal flow strain rates associated with C contours. Hydrogen addition and increasing the RZ size lessen the tendency of flames to be locally extinguished.

  4. Synthesis of monodisperse silver nanoparticles for ink-jet printed flexible electronics

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Zhiliang; Zhang Xingye; Xin Zhiqing; Deng Mengmeng; Wen Yongqiang; Song Yanlin, E-mail: zhangxy@iccas.ac.cn, E-mail: ylsong@iccas.ac.cn [Beijing National Laboratory for Molecular Sciences (BNLMS), Key Lab of Organic Solids, Laboratory of New Materials, Institute of Chemistry, Chinese Academy of Sciences, Beijing 100190 (China)

    2011-10-21

    In this study, monodisperse silver nanoparticles were synthesized with a new reduction system consisting of adipoyl hydrazide and dextrose at ambient temperature. By this facile and rapid approach, high concentration monodisperse silver nanoparticles were obtained on a large scale at low protectant/AgNO{sub 3} mass ratio which was highly beneficial to low cost and high conductivity. Based on the synthesized monodisperse silver nanoparticles, conductive inks were prepared with water, ethanol and ethylene glycol as solvents, and were expected to be more environmentally friendly. A series of electrocircuits were fabricated by ink-jet printing silver nanoparticle ink on paper substrate with a commercial printer, and they had low resistivity in the range of 9.18 x 10{sup -8}-8.76 x 10{sup -8} {Omega} m after thermal treatment at 160 {sup 0}C for 30 min, which was about five times that of bulk silver (1.586 x 10{sup -8} {Omega} m). Moreover, a radio frequency identification (RFID) antenna was fabricated by ink-jet printing, and 6 m wireless identification was realized after an Alien higgs-3 chip was mounted on the printed antenna by the flip-chip method. These flexible electrocircuits produced by ink-jet printing would have enormous potential for low cost electrodes and sensor devices.

  5. Synthesis of monodisperse silver nanoparticles for ink-jet printed flexible electronics.

    Science.gov (United States)

    Zhang, Zhiliang; Zhang, Xingye; Xin, Zhiqing; Deng, Mengmeng; Wen, Yongqiang; Song, Yanlin

    2011-10-21

    In this study, monodisperse silver nanoparticles were synthesized with a new reduction system consisting of adipoyl hydrazide and dextrose at ambient temperature. By this facile and rapid approach, high concentration monodisperse silver nanoparticles were obtained on a large scale at low protectant/AgNO(3) mass ratio which was highly beneficial to low cost and high conductivity. Based on the synthesized monodisperse silver nanoparticles, conductive inks were prepared with water, ethanol and ethylene glycol as solvents, and were expected to be more environmentally friendly. A series of electrocircuits were fabricated by ink-jet printing silver nanoparticle ink on paper substrate with a commercial printer, and they had low resistivity in the range of 9.18 × 10( - 8)-8.76 × 10( - 8) Ω m after thermal treatment at 160 °C for 30 min, which was about five times that of bulk silver (1.586 × 10( - 8) Ω m). Moreover, a radio frequency identification (RFID) antenna was fabricated by ink-jet printing, and 6 m wireless identification was realized after an Alien higgs-3 chip was mounted on the printed antenna by the flip-chip method. These flexible electrocircuits produced by ink-jet printing would have enormous potential for low cost electrodes and sensor devices.

  6. System identification of jet engines

    Energy Technology Data Exchange (ETDEWEB)

    Sugiyama, N.

    2000-01-01

    System identification plays an important role in advanced control systems for jet engines, in which controls are performed adaptively using data from the actual engine and the identified engine. An identification technique for jet engine using the Constant Gain Extended Kalman Filter (CGEKF) is described. The filter is constructed for a two-spool turbofan engine. The CGEKF filter developed here can recognize parameter change in engine components and estimate unmeasurable variables over whole flight conditions. These capabilities are useful for an advanced Full Authority Digital Electric Control (FADEC). Effects of measurement noise and bias, effects of operating point and unpredicted performance change are discussed. Some experimental results using the actual engine are shown to evaluate the effectiveness of CGEKF filter.

  7. Poynting Jets from Accretion Disks

    CERN Document Server

    Lovelace, R V E; Ustyugova, G V; Romanova, M M; Colgate, S A

    2002-01-01

    The powerful narrow jets observed to emanate from many compact accreting objects may arise from the twisting of a magnetic field threading a differentially rotating accretion disk which acts to magnetically extract angular momentum and energy from the disk. Two main regimes have been discussed, {\\it hydromagnetic outflows}, which have a significant mass flux and have energy and angular momentum carried by both the matter and the electromagnetic field and, Poynting outflows, where the mass flux is negligible and energy and angular momentum are carried predominantly by the electromagnetic field. Here we consider a Keplerian disk initially threaded by a dipole-like magnetic field and we present solutions of the force-free Grad-Shafranov equation for the coronal plasma. We find solutions with Poynting jets where there is a continuous outflow of energy and toroidal magnetic flux from the disk into the external space. This behavior contradicts the commonly accepted ``theorem'' of Solar plasma physics that the motio...

  8. Jet drops from microbubble rupture

    Science.gov (United States)

    Yu, Yingxian; Bartlett, Casey; Bird, James

    2014-11-01

    When a bubble bursts at an interface, the surface energy creates an upward jet that can break into smaller droplets. Extensive research has demonstrated that the size of the droplets depends on the size of the initial bubbles. Yet this research has almost entirely been conducted for bubbles that are larger than 100 microns. As the bubbles approach 100 microns, the linear relation seems to deviate, although there have not been systematic experiments in this regime - mainly because these smaller bubbles and the even smaller droplets that they create have been difficult to visualize in the past. Here we directly measure the jetting phenomena for bubbles that are smaller than 100 micron using a combination of microfluidics and high-speed photography, and we relate our results to theory. Lab Name: Interfacial Fluidic Dynamics Laboratory Faculty Mentor's Name: James C. Bird.

  9. Simple thermodynamics of jet engines

    Science.gov (United States)

    Patrício, Pedro; Tavares, José M.

    2010-08-01

    We use the first and second laws of thermodynamics to analyze the behavior of an ideal jet engine. Simple analytical expressions for the thermal efficiency, the overall efficiency, and the reduced thrust are derived. We show that the thermal efficiency depends only on the compression ratio r and on the velocity of the aircraft. The other two performance measures depend also on the ratio of the temperature at the turbine to the inlet temperature in the engine, T3/Ti. An analysis of these expressions shows that it is not possible to choose an optimal set of values of r and T3/Ti that maximize both the overall efficiency and thrust. We study how irreversibilities in the compressor and the turbine decrease the overall efficiency of jet engines and show that this effect is more pronounced for smaller T3/Ti.

  10. Jet fuels from synthetic crudes

    Science.gov (United States)

    Antoine, A. C.; Gallagher, J. P.

    1977-01-01

    An investigation was conducted to determine the technical problems in the conversion of a significant portion of a barrel of either a shale oil or a coal synthetic crude oil into a suitable aviation turbine fuel. Three syncrudes were used, one from shale and two from coal, chosen as representative of typical crudes from future commercial production. The material was used to produce jet fuels of varying specifications by distillation, hydrotreating, and hydrocracking. Attention is given to process requirements, hydrotreating process conditions, the methods used to analyze the final products, the conditions for shale oil processing, and the coal liquid processing conditions. The results of the investigation show that jet fuels of defined specifications can be made from oil shale and coal syncrudes using readily available commercial processes.

  11. Efficiency of SparkJet

    Science.gov (United States)

    Golbabaei-Asl, M.; Knight, D.; Wilkinson, S.

    2013-01-01

    The thermal efficiency of a SparkJet is evaluated by measuring the impulse response of a pendulum subject to a single spark discharge. The SparkJet is attached to the end of a pendulum. A laser displacement sensor is used to measure the displacement of the pendulum upon discharge. The pendulum motion is a function of the fraction of the discharge energy that is channeled into the heating of the gas (i.e., increasing the translational-rotational temperature). A theoretical perfect gas model is used to estimate the portion of the energy from the heated gas that results in equivalent pendulum displacement as in the experiment. The earlier results from multiple runs for different capacitances of C = 3, 5, 10, 20, and 40(micro)F demonstrate that the thermal efficiency decreases with higher capacitive discharges.1 In the current paper, results from additional run cases have been included and confirm the previous results

  12. On plane submerged laminar jets

    Science.gov (United States)

    Coenen, Wilfried; Sanchez, Antonio L.

    2016-11-01

    We address the laminar flow generated when a developed stream of liquid of kinematic viscosity ν flowing along channel of width 2 h discharges into an open space bounded by two symmetric plane walls departing from the channel rim with an angle α 1 . Attention is focused on values of the jet volume flux 2 Q such that the associated Reynolds number Re = Qh / ν is of order unity. The formulation requires specification of the boundary conditions far from the channel exit. If the flow is driven by the volume flux, then the far-field solution corresponds to Jeffery-Hamel self-similar flow. However, as noted by Fraenkel (1962), such solutions exist only for α potential flow driven by the jet entrainment, and a Falkner-Skan near-wall boundary layer. Numerical integrations of the Navier-Stokes equations are used to ascertain the existence of these different solutions.

  13. Piezoelectric actuator for pulsating jets

    Science.gov (United States)

    Brissaud, Michel; Gonnard, Paul; Bera, Jean-Christophe; Sunyach, Michel

    2000-08-01

    Recent researches in aeronautics showed that fluidic actuator systems could offer possibilities for drag reduction and lift improvement. To this end many actuator types were designed. This paper deals with the design, fabrication and test of piezoelectric actuator in order to generate pulsated jets normal to a surface and control air flow separation. It is based on the flexural displacement of a rectangular metal plate clamped on one of its large edge. Piezoelectric patches cemented on the plate were used for driving into vibration the actuator. Experimental measurements show that pulsed flow velocities are adjustable from 1.5m/s to 35m/s through a 100x1mm2 slit andwithin a 100 to 400 Hz frequency range. Prototype provides the jet performances classically required for active control flow.

  14. Tagging and suppression of pileup jets

    CERN Document Server

    The ATLAS collaboration

    2014-01-01

    The suppression of pileup jets has been a crucial component of many physics analyses using 2012 LHC proton-proton collisions. In ATLAS, tracking information has been used to calculate a variable called the jet-vertex-fraction, which is the fraction of the total mo- mentum of tracks in the jet which is associated to the primary vertex. Imposing a minimum on this variable rejects the majority of pileup jets, but leads to hard-scatter jet efficiencies that depend on the number of reconstructed primary vertices in the event ($N_{Vtx}$). In this note, new track-based variables to suppress pileup jets are developed in such a way that the resulting hard-scatter jet efficiency is stable as a function of $N_{Vtx}$. A multivariate combina- tion of two such variables called the jet-vertex-tagger is constructed. In addition, it is shown that jet-vertex association can be applied to large-R jets, providing a track-based grooming technique that is as powerful as calorimeter-based trimming but based on complementary trackin...

  15. Adverse health effects of ethylene oxide and occupational exposure limits.

    Science.gov (United States)

    Sheikh, K

    1984-01-01

    The proposed revision of the US standard for occupational exposure to ethylene oxide has recently been topical and controversial. Most of the recent experimental and epidemiological evidence of health effects, which provoked lowering the permissible exposure limit, appears to be unreliable and insufficient for risk assessment.

  16. Analysis of the complexation reaction between Ag+ and ethylene

    NARCIS (Netherlands)

    Nymeijer, Kitty; Visser, Tymen; Brilman, Wim; Wessling, Matthias

    2004-01-01

    In the present work the reversible, bimolecular (1,1) reaction between ethylene and Ag+ in concentrated AgNO3(aq) solutions is analyzed. Due to interactions between the positively charged Ag+ ions and the negatively charged NO3- ions, the silver nitrate is not completely dissociated and the actual f

  17. Enhanced Ionic Conductivity of Poly(Ethylene Imine) Phosphate

    DEFF Research Database (Denmark)

    Senadeera, G.K.R.; Careem, M.A.; Skaarup, Steen;

    1996-01-01

    The conductivity of mixtures of phosphoric acid with poly(ethylene imine) has been studied, and it was found that the conductivity of such mixtures with high acid content can be enhanced by the addition of highly dispersed silica (fumed silica). At the same time, silica addition increases the sti...

  18. Polyamine levels and tomato fruit development: possible interaction with ethylene.

    Science.gov (United States)

    Saftner, R A; Baldi, B G

    1990-02-01

    Fruits of tomato, Lycopersicon esculentum Mill. cv Liberty, ripen slowly and have a prolonged keeping quality. Ethylene production and the levels of polyamines in pericarp of cv Liberty, Pik Red, and Rutgers were measured in relation to fruit development. Depending on the stage of fruit development, Liberty produced between 16 and 38% of the ethylene produced by Pik Red and Rutgers. The polyamines putrescine, spermidine, and spermine were present in all cultivars. Cadaverine was detected only in Rutgers. Levels of putrescine and spermidine declined between the immature and mature green stages of development and prior to the onset of climacteric ethylene production. In Pik Red and Rutgers, the decline persisted, whereas in Liberty, the putrescine level increased during ripening. Ripe pericarp of Liberty contained about three and six times more free (unconjugated) polyamines than Pik Red and Rutgers, respectively. No pronounced changes in spermidine or cadaverine occurred during ripening. The increase in the free polyamine level in ripe pericarp of Liberty may account for the reduction of climacteric ethylene production, and prolonged storage life.

  19. SYNTHESIS OF NiO NANOPARTICLES IN ETHYLENE GLYCOL

    Institute of Scientific and Technical Information of China (English)

    Desheng Ai; Xiaming Dai; Qingfeng Li; Changsheng Deng; Shinhoo Kang

    2004-01-01

    NiO nanoparticles with well-dispersed property were prepared via a wet chemical method in ethylene glycol (EG) without soluble polymer as a protective agent. The mechanism of chemical process was proposed based on color change during the experiment. The dispersion function of EG was discussed.

  20. Proteomic Responses in Arabidopsis thaliana Seedlings Treated with Ethylene

    Science.gov (United States)

    Ethylene (ET) is a volatile plant growth hormone that most famously modulates fruit ripening, but it also controls plant growth, development and stress responses. In Arabidopsis thaliana, ET is perceived by receptors in the endoplasmic reticulum, and a signal is transduced through a protein kinase,...

  1. Direct Routes from Synthesis Gas to Ethylene Glycol.

    Science.gov (United States)

    Dombek, B. D.

    1986-01-01

    Discusses the synthesis of ethylene glycol from carbon monoxide and hydrogen using bimetallic catalysts. Although this technology has not been implemented, it illustrates two important future trends, namely, use of bimetallic catalysts and use of coal-derived carbon monoxide and hydrogen as a new feed stock. (JN)

  2. IRIS Toxicological Review of Ethylene Glycol Mono Butyl ...

    Science.gov (United States)

    EPA has finalized the Toxicological Review of Ethylene Glycol Mono Butyl Ether: in support of the Integrated Risk Information System (IRIS). Now final, this assessment may be used by EPA’s program and regional offices to inform decisions to protect human health. N/A

  3. Challenges in the diagnosis of ethylene glycol poisoning.

    Science.gov (United States)

    McQuade, David J; Dargan, Paul I; Wood, David M

    2014-03-01

    Ethylene glycol poisoning, while uncommon, is clinically significant due to the associated risk of severe morbidity or lethality and it continues to occur in many countries around the world. The clinical presentation of ethylene glycol toxicity, while classically described in three phases, varies widely and when combined with the range of differential diagnoses that must be considered makes diagnosis challenging. Early and accurate detection is important in these patients, however, as there is a need to start antidotal treatment early to prevent serious harm. In this article, we will review the literature and provide guidance regarding the diagnosis of ethylene glycol poisoning. While gas chromatography is the gold standard, the usefulness of this test is hampered by delays in access due to availability. Consequently, there are several surrogate markers that can give an indication of ethylene glycol exposure but these must be interpreted with caution and within the clinical context. An in-depth review of these tests, particularly the detection of a raised osmolar gap or an raised anion gap acidosis, will form the main focus of this article.

  4. Ethylene glycol emissions from on-road vehicles.

    Science.gov (United States)

    Wood, Ezra C; Knighton, W Berk; Fortner, Ed C; Herndon, Scott C; Onasch, Timothy B; Franklin, Jonathan P; Worsnop, Douglas R; Dallmann, Timothy R; Gentner, Drew R; Goldstein, Allen H; Harley, Robert A

    2015-03-17

    Ethylene glycol (HOCH2CH2OH), used as engine coolant for most on-road vehicles, is an intermediate volatility organic compound (IVOC) with a high Henry's law coefficient. We present measurements of ethylene glycol (EG) vapor in the Caldecott Tunnel near San Francisco, using a proton transfer reaction mass spectrometer (PTR-MS). Ethylene glycol was detected at mass-to-charge ratio 45, usually interpreted as solely coming from acetaldehyde. EG concentrations in bore 1 of the Caldecott Tunnel, which has a 4% uphill grade, were characterized by infrequent (approximately once per day) events with concentrations exceeding 10 times the average concentration, likely from vehicles with malfunctioning engine coolant systems. Limited measurements in tunnels near Houston and Boston are not conclusive regarding the presence of EG in sampled air. Previous PTR-MS measurements in urban areas may have overestimated acetaldehyde concentrations at times due to this interference by ethylene glycol. Estimates of EG emission rates from the Caldecott Tunnel data are unrealistically high, suggesting that the Caldecott data are not representative of emissions on a national or global scale. EG emissions are potentially important because they can lead to the formation of secondary organic aerosol following oxidation in the atmospheric aqueous phase.

  5. Glycolic acid production using ethylene glycol-oxidizing microorganisms.

    Science.gov (United States)

    Kataoka, M; Sasaki, M; Hidalgo, A R; Nakano, M; Shimizu, S

    2001-10-01

    Screening for microorganisms oxidizing ethylene glycol to glycolic acid was carried out. Among stock cultures, several yeasts and acetic acid bacteria showed high glycolic acid producing activity. Pichia naganishii AKU 4267 formed the highest concentration of glycolic acid, 35.3 g/l, from 10% (v/v) ethylene glycol (molar conversion yield, 26.0%). Among soil isolates, Rhodotorula sp. 3Pr-126, isolated using propylene glycol as a sole carbon source, formed the highest concentration of glycolic acid, 25.1 g/l, from 10% (v/v) ethylene glycol (molar conversion yield, 18.5%). Rhodotorula sp. 3Pr-126 showed higher activity toward 20% (v/v) ethylene glycol than P. naganishii AKU 4267. Optimization of the conditions for glycolic acid production was investigated using P. naganishii AKU 4267 and Rhodotorula sp. 3Pr-126. Under the optimized conditions, P. naganishii AKU 4267 and Rhodotorula sp. 3Pr-126 formed 105 and 110 g/l of glycolic acid (corrected molar conversion yields, 88.0 and 92.2%) during 120 h of reaction, respectively.

  6. RTE1, A Novel Regulator of Ethylene Receptor Function

    Energy Technology Data Exchange (ETDEWEB)

    Caren Chang (PI)

    2013-02-05

    RTE1 is a novel conserved gene found in both plants and animals. The main aims of this project were to: 1) examine Arabidopsis RTE1 function using genetic and cell biological analyses, and 2) determine whether the Arabidopsis RTH gene plays a role similar to that of RTE1 in ethylene signaling.

  7. Development of new photocatalysts for efficient removal of ethylene

    DEFF Research Database (Denmark)

    Nielsen, Morten Godtfred

    The aim of this thesis has been to remove ethylene/ethene (from here on called ethene because it is shortest) photocatalytically with the primary purpose of preventing fruit ripening during shipping. This has been achieved based on TiO2. The topic has been approached from different angles. The most...

  8. Flower development, reproduction and fruit ripening : the role of ethylene

    NARCIS (Netherlands)

    Martinis, Domenico de

    2006-01-01

    This thesis approaches the study of the role of ethylene in different aspects of plant reproduction; flower development, pollination, fruit ripening and spoilage. These different aspects have been studied at physiological, biochemical and molecular level. Chapter I, general introduction is divided i

  9. Optical properties, ethylene production and softening in mango fruits

    NARCIS (Netherlands)

    Eccher Zerbini, P.C.; Vanoli, M.; Rizzolo, A.; Grassi, M.; Meirelles de Azevedo Pementel, A.; Spinelli, L.; Torricelli, A.

    2015-01-01

    Firmness decay, chlorophyll breakdown and carotenoid accumulation, controlled by ethylene, are major ripening events in mango fruit. Pigment content and tissue structure affect the optical properties of the mesocarp, which can be measured nondestructively in the intact fruit by time-resolved reflect

  10. Direct Routes from Synthesis Gas to Ethylene Glycol.

    Science.gov (United States)

    Dombek, B. D.

    1986-01-01

    Discusses the synthesis of ethylene glycol from carbon monoxide and hydrogen using bimetallic catalysts. Although this technology has not been implemented, it illustrates two important future trends, namely, use of bimetallic catalysts and use of coal-derived carbon monoxide and hydrogen as a new feed stock. (JN)

  11. Inhibition of auxin-induced ethylene production by lycoricidinol

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Bin-G.; Lee, June-S.; Oh, Seung-Eun (Yonsei Univ., Seoul (Republic of Korea)); Horiuchi, Yuko; Imaseki, Hidemasa

    1984-03-01

    Lycoricidinol, a natural growth inhibitor isolated from bulbs of Lycoris radiata Herb. strongly suppressed auxin-induced ethylene production from the hypocotyl segments of etiolated mung bean (Vigna radiata Wilczek) seedlings. The inhibitor did not significantly inhibit ethylene formation from its immediate precursor, 1-aminocyclopropane-1-carboxylic acid (ACC), during short-term (up to 4h) incubation. The ACC content in tissue treated with IAA was reduced by lycoricidinol in close parallel with the inhibition of ethylene production. Examination of radioactive metabolites in tissues labeled with 3,4-/sup 14/C-methionine indicated that reduction of the ACC content was not due to any possible promotive effect of lycoricidinol on conjugation of ACC with malonate. Lycoricidinol showed no inhibitory effect on the activity of ACC synthase if applied in vitro, but it almost completely abolished the increase in the enzyme activity when applied in vivo during incubation of the tissue with IAA. Lycoricidinol also strongly inhibited incorporation of /sup 14/C-leucine into protein in the tissue. The suppression of the enzyme induction and, in turn, that of ethylene production by lycoricidinol were interpreted as being due to the inhibition of protein synthesis.

  12. Flower development, reproduction and fruit ripening : the role of ethylene

    NARCIS (Netherlands)

    Martinis, Domenico de

    2006-01-01

    This thesis approaches the study of the role of ethylene in different aspects of plant reproduction; flower development, pollination, fruit ripening and spoilage. These different aspects have been studied at physiological, biochemical and molecular level. Chapter I, general introduction is divided i

  13. Role of ethylene in the germination metabolism of ricinus communis

    Science.gov (United States)

    Cristescu, Simona; Dumitras, Dan C.; Godeanu, Adriana

    1999-03-01

    A CO2 laser-based photoacoustic method has been used to monitor the ethylene (C2H4) released by castor bean (Ricinus communis) seeds during germination. The relationship between the evolution of the C2H4 germinating seeds and the respiration intensity is presented.

  14. Editorial on Future Jet Technologies

    Science.gov (United States)

    Gal-Or, Benjamin

    2014-08-01

    Advanced jet engines do not operate in an application vacuum. Their optimal use in advanced military applications drives much of their basic innovative research and development, especially when new needs arise in the rapidly changing domains of stealth-agile, fighter aircraft and tailless-stealth, Jet-Steered, Unmanned Air Vehicles (JS-UAV). For these reasons we periodically update this Journal with new trends that affect, and sometimes control, research and development of future jet-engines. One relevant example is the recently unmasked RQ-180 stealth-tailless drone, which is an improved version of the smaller, RQ-170 captured by Iran. Most important, with the new X-47B/C tailless-stealth JS-UAV, it is to dominate future uses of fuel-efficient jet-engines, especially for operating in dusty environments. The RQ-180 has been secretly designed and funded since 2008. It is based on a classified, 1986, parent Israeli Patents 78402, which protect hundreds design and testing trade secrets taken from 1986 to 1997 by the United States Government (USG) via classified contracts with USG-Contractors Boeing, Lockheed, General Dynamics and General Electric, as revealed by a December 6, 2013 Aviation Week [1-3] and U.S. Court of Appeals for the Federal Circuit, Case 2014-5028, Docket 12 [4]. The new RQ-180 design explains the recent U.S. Air Force ISR shift away from "permissive" environments - such as Iraq and Afghanistan, where non-stealthy Global Hawk and General Atomics' Reaper operate - toward new missions in highly "contested" or strongly "denied" enemy airspaces.

  15. Jet Production by Virtual Photons

    CERN Document Server

    Friberg, C; Friberg, Christer; Sjöstrand, Torbjörn

    2000-01-01

    The production of jets is studied in collisions of virtual photons, gamma*-p and gamma*-gamma*, specifically for applications at HERA and LEP2. Photon flux factors are convoluted with matrix elements involving either direct or resolved photons and, for the latter, with parton distributions of the photon. Special emphasis is put on the range of uncertainty in the modeling of the resolved component. The resulting model is compared with existing data.

  16. Somali Jet Changes under the Global Warming

    Institute of Scientific and Technical Information of China (English)

    LIN Meijing; FAN Ke; WANG Huijun

    2008-01-01

    Somali Jet changes will influence the variability of Asian monsoon and climate. How would Somali Jet changes respond to the global warming in the future climate? To address this question, we first evaluate the ability of IPCC-AR4 climate models and perform the 20th century climate in coupled models (20C3M) experiments to reproduce the observational features of the low level Somali Jet in JJA (June-July-August) for the period 1976-1999. Then, we project and discuss the changes of Somali Jet under the climate change of Scenario A2 (SRESA2) for the period 2005-2099. The results show that 18 IPCC-AR4 models have performed better in describing the climatological features of Somali Jet in the present climate simulations. Analysis of Somali Jet intensity changes from the multi-model ensemble results for the period 2005-2099 shows a weakened Somali Jet in the early 21st century (2010-2040), the strongest Somali Jet in the middle 21st century (2050-2060), as well as the weakest Somali Jet at the end of the 21st century (2070-2090). Compared with the period 1976-1999, the intensity of Somali Jet is weakening in general, and it becomes the weakest at the end of the 21st century. The results also suggest that the relationship between the intensity of Somali Jet in JJA and the increment of global mean surface air temperature is nonlinear, which is reflected differently among the models, suggesting the uncertainty of the IPCC-AR4 models. Considering the important role of Somali Jet in the Indian monsoon and East Asian monsoon and climate of China, the variability of Somali Jet and its evolvement under the present climate or future climate changes need to be further clarified.

  17. Ethylene Glycol Metabolism in the Acetogen Acetobacterium woodii.

    Science.gov (United States)

    Trifunović, Dragan; Schuchmann, Kai; Müller, Volker

    2016-01-19

    The acetogenic bacterium Acetobacterium woodii is able to grow by the oxidation of diols, such as 1,2-propanediol, 2,3-butanediol, or ethylene glycol. Recent analyses demonstrated fundamentally different ways for oxidation of 1,2-propanediol and 2,3-butanediol. Here, we analyzed the metabolism of ethylene glycol. Our data demonstrate that ethylene glycol is dehydrated to acetaldehyde, which is then disproportionated to ethanol and acetyl coenzyme A (acetyl-CoA). The latter is further converted to acetate, and this pathway is coupled to ATP formation by substrate-level phosphorylation. Apparently, the product ethanol is in part further oxidized and the reducing equivalents are recycled by reduction of CO2 to acetate in the Wood-Ljungdahl pathway. Biochemical data as well as the results of protein synthesis analysis are consistent with the hypothesis that the propane diol dehydratase (PduCDE) and CoA-dependent propionaldehyde dehydrogenase (PduP) proteins, encoded by the pdu gene cluster, also catalyze ethylene glycol dehydration to acetaldehyde and its CoA-dependent oxidation to acetyl-CoA. Moreover, genes encoding bacterial microcompartments as part of the pdu gene cluster are also expressed during growth on ethylene glycol, arguing for a dual function of the Pdu microcompartment system. Acetogenic bacteria are characterized by their ability to use CO2 as a terminal electron acceptor by a specific pathway, the Wood-Ljungdahl pathway, enabling in most acetogens chemolithoautotrophic growth with H2 and CO2. However, acetogens are very versatile and can use a wide variety of different substrates for growth. Here we report on the elucidation of the pathway for utilization of ethylene glycol by the model acetogen Acetobacterium woodii. This diol is degraded by dehydration to acetaldehyde followed by a disproportionation to acetate and ethanol. We present evidence that this pathway is catalyzed by the same enzyme system recently described for the utilization of 1

  18. Factorization for jet radius logarithms in jet mass spectra at the LHC

    Science.gov (United States)

    Kolodrubetz, Daniel W.; Pietrulewicz, Piotr; Stewart, Iain W.; Tackmann, Frank J.; Waalewijn, Wouter J.

    2016-12-01

    To predict the jet mass spectrum at a hadron collider it is crucial to account for the resummation of logarithms between the transverse momentum of the jet and its invariant mass m J . For small jet areas there are additional large logarithms of the jet radius R, which affect the convergence of the perturbative series. We present an analytic framework for exclusive jet production at the LHC which gives a complete description of the jet mass spectrum including realistic jet algorithms and jet vetoes. It factorizes the scales associated with m J , R, and the jet veto, enabling in addition the systematic resummation of jet radius logarithms in the jet mass spectrum beyond leading logarithmic order. We discuss the factorization formulae for the peak and tail region of the jet mass spectrum and for small and large R, and the relations between the different regimes and how to combine them. Regions of experimental interest are classified which do not involve large nonglobal logarithms. We also present universal results for nonperturbative effects and discuss various jet vetoes.

  19. The flow feature of transverse hydrogen jet in presence of micro air jets in supersonic flow

    Science.gov (United States)

    Barzegar Gerdroodbary, M.; Amini, Younes; Ganji, D. D.; Takam, ​M. Rahimi

    2017-03-01

    Scramjet is found to be the efficient method for the space shuttle. In this paper, numerical simulation is performed to investigate the fundamental flow physics of the interaction between an array of fuel jets and multi air jets in a supersonic transverse flow. Hydrogen as a fuel is released with a global equivalence ratio of 0.5 in presence of micro air jets on a flat plate into a Mach 4 crossflow. The fuel and air are injected through streamwise-aligned flush circular portholes. The hydrogen is injected through 4 holes with 7dj space when the air is injected in the interval of the hydrogen jets. The numerical simulation is performed by using the Reynolds-averaged Navier-Stokes equations with Menter's Shear Stress Transport (SST) turbulence model. Both the number of air jets and jet-to-freestream total pressure ratio are varied in a parametric study. The interaction of the fuel and air jet in the supersonic flow present extremely complex feature of fuel and air jet. The results present various flow features depending upon the number and mass flow rate of micro air jets. These flow features were found to have significant effects on the penetration of hydrogen jets. A variation of the number of air jets, along with the jet-to-freestream total pressure ratio, induced a variety of flow structure in the downstream of the fuel jets.

  20. Factorization for jet radius logarithms in jet mass spectra at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Kolodrubetz, Daniel W. [Center for Theoretical Physics, Massachusetts Institute of Technology,Cambridge, MA 02139 (United States); Pietrulewicz, Piotr [Theory Group, Deutsches Elektronen-Synchrotron (DESY),Notkestraße 85, D-22607 Hamburg (Germany); Stewart, Iain W. [Center for Theoretical Physics, Massachusetts Institute of Technology,Cambridge, MA 02139 (United States); Tackmann, Frank J. [Theory Group, Deutsches Elektronen-Synchrotron (DESY),Notkestraße 85, D-22607 Hamburg (Germany); Waalewijn, Wouter J. [ITFA, University of Amsterdam,Science Park 904, 1018 XE, Amsterdam (Netherlands); Nikhef, Theory Group,Science Park 105, 1098 XG, Amsterdam (Netherlands)

    2016-12-14

    To predict the jet mass spectrum at a hadron collider it is crucial to account for the resummation of logarithms between the transverse momentum of the jet and its invariant mass m{sub J}. For small jet areas there are additional large logarithms of the jet radius R, which affect the convergence of the perturbative series. We present an analytic framework for exclusive jet production at the LHC which gives a complete description of the jet mass spectrum including realistic jet algorithms and jet vetoes. It factorizes the scales associated with m{sub J}, R, and the jet veto, enabling in addition the systematic resummation of jet radius logarithms in the jet mass spectrum beyond leading logarithmic order. We discuss the factorization formulae for the peak and tail region of the jet mass spectrum and for small and large R, and the relations between the different regimes and how to combine them. Regions of experimental interest are classified which do not involve large nonglobal logarithms. We also present universal results for nonperturbative effects and discuss various jet vetoes.

  1. Ethylene oxidation chemistry in a well-stirred reactor

    Energy Technology Data Exchange (ETDEWEB)

    Marinov, N. [Lawrence Livermore National Lab., CA (United States); Malte, P. [Univ. of Washington, Seattle, WA (United States). Dept. of Mechanical Engineering

    1994-09-01

    Ethylene is an important intermediate in the combustion of methane, larger aliphatic hydrocarbons, and aromatics. Detailed fuel-lean C{sub 2}H{sub 4}H{sub 2}O/air well-stirred reactor data by Thornton were used to analyze reported combustion chemistry mechanisms and the development of this study`s ethylene oxidation mechanism. The data set had been obtained for the temperature range 1,003 to 1,253 K and ethylene-oxygen equivalence ratio range 0.086 to 0.103, at atmospheric pressure. Mechanisms were derived from reaction sets of Westbrook and Pitz, and Dagaut, Cathonnet and Boettner. Examination of each reported mechanism indicated unusually large kinetic rates for the vinyl decomposition reaction were used in order to obtain agreement with the Thornton data set. An ethylene oxidation model was developed in order to address the mechanistic problems of the previous models. This study`s mechanism well simulated the overall rate of ethylene oxidation and concentration profiles of CO, CO{sub 2}, H{sub 2}, CH{sub 2}O, C{sub 2}H{sub 2}, CH{sub 3}OH, CH{sub 4}, and C{sub 2}H{sub 6}. Successful predictions by the model were dependent on a new high temperature vinyl oxidation reaction route, C{sub 2}H{sub 3} + O{sub 2} = CH{sub 2}CHO + O with a branching ratio of 1.19--1.21 at 1,053 K to 1.63--2.47 at 1,253 K. The branching ratio values were dependent upon the extent of fall-off for the C{sub 2}H{sub 3} + O{sub 2} = CH{sub 2}O + HCO reaction. 132 refs.

  2. The Effect of Ethylene and Propylene Pulses on Respiration, Ripening Advancement, Ethylene-Forming Enzyme, and 1-Aminocyclopropane-1-carboxylic Acid Synthase Activity in Avocado Fruit.

    Science.gov (United States)

    Starrett, D A; Laties, G G

    1991-03-01

    When early-season avocado fruit (Persea americana Mill. cv Hass) were treated with ethylene or propylene for 24 hours immediately on picking, the time to the onset of the respiratory climacteric, i.e. the lag period, remained unchanged compared with that in untreated fruit. When fruit were pulsed 24 hours after picking, on the other hand, the lag period was shortened. In both cases, however, a 24 hour ethylene or propylene pulse induced a transient increase in respiration, called the pulse-peak, unaccompanied by ethylene production (IL Eaks [1980] Am Soc Hortic Sci 105: 744-747). The pulse also caused a sharp rise in ethylene-forming enzyme activity in both cases, without any increase in the low level of 1-aminocyclopropane-1-carboxylic acid synthase activity. Thus, the shortening of the lag period by an ethylene pulse is not due to an effect of ethylene on either of the two key enzymes in ethylene biosynthesis. A comparison of two-dimensional polyacrylamide gel electrophoresis polypeptide profiles of in vitro translation products of poly(A(+)) mRNA from control and ethylene-pulsed fruit showed both up- and down-regulation in response to ethylene pulsing of a number of genes expressed during the ripening syndrome. It is proposed that the pulse-peak or its underlying events reflect an intrinsic element in the ripening process that in late-season or continuously ethylene-treated fruit may be subsumed in the overall climacteric response. A computerized system that allows continuous readout of multiple samples has established that the continued presentation of exogeneous ethylene or propylene to preclimacteric fruit elicits a dual respiration response comprising the merged pulse-peak and climacteric peak in series. The sequential removal of cores from a single fruit has proven an unsatisfactory sampling procedure inasmuch as coring induces wound ethylene, evokes a positive respiration response, and advances ripening.

  3. Modulation of ethylene responses by OsRTH1 overexpression reveals the biological significance of ethylene in rice seedling growth and development.

    Science.gov (United States)

    Zhang, Wei; Zhou, Xin; Wen, Chi-Kuang

    2012-06-01

    Overexpression of Arabidopsis Reversion-To-ethylene Sensitivity1 (RTE1) results in whole-plant ethylene insensitivity dependent on the ethylene receptor gene Ethylene Response1 (ETR1). However, overexpression of the tomato RTE1 homologue Green Ripe (GR) delays fruit ripening but does not confer whole-plant ethylene insensitivity. It was decided to investigate whether aspects of ethylene-induced growth and development of the monocotyledonous model plant rice could be modulated by rice RTE1 homologues (OsRTH genes). Results from a cross-species complementation test in Arabidopsis showed that OsRTH1 overexpression complemented the rte1-2 loss-of-function mutation and conferred whole-plant ethylene insensitivity in an ETR1-dependent manner. In contrast, OsRTH2 and OsRTH3 overexpression did not complement rte1-2 or confer ethylene insensitivity. In rice, OsRTH1 overexpression substantially prevented ethylene-induced alterations in growth and development, including leaf senescence, seedling leaf elongation and development, coleoptile elongation or curvature, and adventitious root development. Results of subcellular localizations of OsRTHs, each fused with the green fluorescent protein, in onion epidermal cells suggested that the three OsRTHs were predominantly localized to the Golgi. OsRTH1 may be an RTE1 orthologue of rice and modulate rice ethylene responses. The possible roles of auxins and gibberellins in the ethylene-induced alterations in growth were evaluated and the biological significance of ethylene in the early stage of rice seedling growth is discussed.

  4. Jet Reconstruction with charged tracks only in CMS

    CERN Document Server

    Azzurri, Paolo

    2008-01-01

    The performance of jet finding using only charged tracks in CMS has been investigated. Different jet algorithms have been applied to QCD di-jet events, to hadronic $t\\overline{t}$ multi-jet events and on Z+jets events. Results using jets made with tracks only or calorimeter towers are compared for energy response, angular resolution and jet matching to the leading partons. The jet reconstruction performance in the presence of pile-up interactions is presented for the Z+jets sample.

  5. Mechanisms of Plasma Acceleration in Coronal Jets

    Science.gov (United States)

    Soto, N.; Reeves, K.; Savcheva, A. S.

    2016-12-01

    Jets are small explosions that occur frequently in the Sun possibly driven by the local reconfiguration of the magnetic field, or reconnection. There are two types of coronal jets: standard jets and blowout jets. The purpose of this project is to determine which mechanisms accelerate plasma in two different jets, one that occurred in January 17, 2015 at the disk of the sun and another in October 24, 2015 at the limb. Two possible acceleration mechanisms are chromospheric evaporation and magnetic acceleration. Using SDO/AIA, Hinode/XRT and IRIS data, we create height-time plots, and calculate the velocities of each wavelength for both jets. We calculate the potential magnetic field of the jet and the general region around it to gain a more detailed understanding of its structure, and determine if the jet is likely to be either a standard or blowout jet. Finally, we calculate the magnetic field strength for different heights along the jet spire, and use differential emission measures to calculate the plasma density. Once we have these two values, we calculate the Alfven speed. When analyzing our results we are looking for certain patterns in our velocities. If the plasma in a jet is accelerated by chromospheric evaporation, we expect the velocities to increase as function of temperature, which is what we observed in the October 24th jet. The magnetic models for this jet also show the Eiffel Tower shaped structure characteristic of standard jets, which tend to have plasma accelerated by this mechanism. On the other hand, if the acceleration mechanism were magnetic acceleration, we would expect the velocities to be similar regardless of temperature. For the January 17th jet, we saw that along the spire, the velocities where approximately 200 km/s in all wavelengths, but the velocities of hot plasma detected at the base were closer to the Alfven speed, which was estimated to be about 2,000 km/s. These observations suggest that the plasma in the January 17th jet is

  6. Reconnection and Spire Drift in Coronal Jets

    Science.gov (United States)

    Moore, Ronald; Sterling, Alphonse; Falconer, David

    2015-04-01

    It is observed that there are two morphologically-different kinds of X-ray/EUV jets in coronal holes: standard jets and blowout jets. In both kinds: (1) in the base of the jet there is closed magnetic field that has one foot in flux of polarity opposite that of the ambient open field of the coronal hole, and (2) in coronal X-ray/EUV images of the jet there is typically a bright nodule at the edge of the base. In the conventional scenario for jets of either kind, the bright nodule is a compact flare arcade, the downward product of interchange reconnection of closed field in the base with impacted ambient open field, and the upper product of this reconnection is the jet-outflow spire. It is also observed that in most jets of either kind the spire drifts sideways away from the bright nodule. We present the observed bright nodule and spire drift in an example standard jet and in two example blowout jets. With cartoons of the magnetic field and its reconnection in jets, we point out: (1) if the bright nodule is a compact flare arcade made by interchange reconnection, then the spire should drift toward the bright nodule, and (2) if the bright nodule is instead a compact flare arcade made, as in a filament-eruption flare, by internal reconnection of the legs of the erupting sheared-field core of a lobe of the closed field in the base, then the spire, made by the interchange reconnection that is driven on the outside of that lobe by the lobe’s internal convulsion, should drift away from the bright nodule. Therefore, from the observation that the spire usually drifts away from the bright nodule, we infer: (1) in X-ray/EUV jets of either kind in coronal holes the interchange reconnection that generates the jet-outflow spire usually does not make the bright nodule; instead, the bright nodule is made by reconnection inside erupting closed field in the base, as in a filament eruption, the eruption being either a confined eruption for a standard jet or a blowout eruption (as

  7. Neutral Beams from Blazar Jets

    Science.gov (United States)

    Atoyan, Armen M.; Dermer, Charles D.

    2003-03-01

    We treat the production of neutrons, photons, and neutrinos through photomeson interactions of relativistic protons with ambient photons in the compact inner jets of blazars. Internal synchrotron and external isotropic radiation due to scattered optical/UV accretion-disk radiation are considered as target photon fields. Protons are assumed to be accelerated to a maximum energy limited by the size scale and magnetic field of the jet, and by competing energy losses. We characterize the conditions when the photomeson interactions of ultrarelativistic protons become effective, and show that the presence of the external radiation field makes possible strong energy losses for protons with energies Ep>~1015 eV. Without this component, effective energy losses of protons begin at Ep>~1018 eV, and would rapidly disappear with expansion of the blob. We develop a model describing the production and escape of neutrons from a comoving spherical blob, which continue to interact with the ambient external radiation field on the parsec-scale broad-line region (BLR). Neutrons may carry ~10% of the overall energy of the accelerated protons with Ep>~1015 eV outside the BLR. Ultra-high-energy gamma rays produced by photomeson interaction of neutrons outside the blob can also escape the BLR. The escaping neutrons, gamma rays, and neutrinos form a collimated neutral beam with a characteristic opening angle θ~1/Γ, where Γ is the bulk Lorentz factor of the inner jet. Energy and momentum is deposited in the extended jet from the decay of neutrons at distances ld(En)~(En/1017eV) kpc, and through pair-production attenuation of gamma rays with energies Eγ>~1015 eV which propagate to ~10-100 kpc distances. In this scenario, neutral beams of ultra-high-energy gamma rays and neutrons can be the reason for straight extended jets, such as in Pictor A. Fluxes of neutrinos detectable with kilometer-scale neutrino telescopes are predicted from flat-spectrum radio quasars such as 3C 279.

  8. Laser transmission welding of poly(ethylene terephthalate) and biodegradable poly(ethylene terephthalate) - Based blends

    Science.gov (United States)

    Gisario, Annamaria; Veniali, Francesco; Barletta, Massimiliano; Tagliaferri, Vincenzo; Vesco, Silvia

    2017-03-01

    Joining of Poly(Ethylene Terephthalate) PET and its biodegradable derivatives is of high relevance to ensure good productive rate, low cost and operational safety for fabrication of medical and electronic devices, sport equipments as well as for manufacturing of food and drug packaging solutions. In the present investigation, granules of PET and PETs modified by organic additives, which promote biodegradation of the polymeric chains, were prepared by extrusion compounding. The achieved granules were subsequently re-extruded to shape thin (330 μm) flat sheets. Substrates cut from these sheets were joined by Laser Transmission Welding (LTW) with a continuous wave High Power Diode Laser (cw-HPDL). First, based on a qualitative evaluation of the welded joints, the most suitable operational windows for PETs laser joining were identified. Second, characterization of the mechanical properties of the welded joints was performed by tensile tests. Accordingly, Young's modulus of PET and biodegradable PET blends was studied by Takayanagi's model and, based on the experimental results, a novel predicting analytical model derived from the mixture rule was developed. Lastly, material degradation of the polymeric joints was evaluated by FT-IR analysis, thus allowing to identify the main routes to thermal degradation of PET and, especially, of biodegradable PET blends during laser processing.

  9. in situ ring-opening polymerization of hydroxyapatite/poly(ethylene adipate)--(ethylene terephthalate) biomimetic composites

    Indian Academy of Sciences (India)

    Punnama Siriphannon; Pathavuth Monvisade

    2013-02-01

    Hydroxyapatite/poly(ethylene adipate)--poly(ethylene terephthalate) biomaterials (HAp/PEA--PET) have been prepared by ring opening polymerization (ROP) of cyclic oligo(ethylene adipate)--oligo(ethylene terephthalate) (C-OEA--C-OET) in the porous hydroxyapatite (HAp) scaffolds at 250 °C for 24 h under vacuum. The content of ROP-PEA--PET in the HAp/PEA--PET composite was about 20 wt% with the values of number average molecular weight ($\\bar{M}$n) and weight average molecular weight ($\\bar{M}$W) of 3380 and 7160 g/mol, respectively. Compressive strength and modulus of the HAp/PEA--PET composites were about 29 and 246 MPa, respectively. These mechanical properties were higher than those of the porous HAp templates and natural cancellous bone. In vitro bioactivity of the HAp/PEA--PET composites was studied by soaking in simulated body fluid (SBF) under the flowing system at the rate of 130 mL/day for 7, 14, 21 and 28 days. The formation of hydroxyapatite nanocrystals was observed on the composite surfaces through the consumption of calcium and phosphorus from the SBF solution, indicating the bioactivity of these HAp/PEA--PET composites. These results indicated the competency of HAp/PEA--PET composites for biomedical applications.

  10. Phenomenological and theoretical developments in jet physics at the LHC

    CERN Document Server

    Cacciari, Matteo

    2015-01-01

    We review the history of jets in high energy physics, and describe in more detail the developments of the past ten years, discussing new algorithms for jet finding and their main characteristics, and summarising the status of perturbative calculations for jet cross sections in hadroproduction. We also describe the emergence of jet grooming and tagging techniques and their application to boosted jets analyses.

  11. Ethylene adsorption on regularly stepped copper surface: C 2H 4 on Cu(210)

    Science.gov (United States)

    Yamazaki, Daichi; Okada, Michio; Franco, Francisco C., Jr.; Kasai, Toshio

    2011-05-01

    Ethylene adsorption on regularly stepped Cu(210) surface was investigated with infrared reflection-adsorption spectroscopy and temperature programmed desorption. At 90 K, π-bonded ethylene was adsorbed on Cu(210) molecularly and all species were desorbed below 160 K. There were three types of π-bonded ethylene on the surface. Recent experimental studies have suggested that ethylene is dehydrogenated on Cu(410) due to the regular step [Kravchuk et al ., J. Phys. Chem. C, 113 (2009) 20881]. However, neither the formation of di-σ-bonded ethylene nor dehydrogenation occurred on Cu(210).

  12. Polyamines inhibit biosynthesis of ethylene in higher plant tissue and fruit protoplasts.

    Science.gov (United States)

    Apelbaum, A; Burgoon, A C; Anderson, J D; Lieberman, M

    1981-08-01

    Ethylene production in apple fruit and protoplasts and in leaf tissue was inhibited by spermidine or spermine. These polyamines, as well as putrescine, inhibited auxin-induced ethylene production and the conversion of methionine and 1-aminocyclopropane-1-carboxylic acid to ethylene. Polyamines were more effective as inhibitors of ethylene synthesis at the early, rather than at the late, stages of fruit ripening. Ca(2+) in the incubation medium reduced the inhibitory effect caused by the amines. A possible mode of action by which polyamines inhibit ethylene production is discussed.

  13. Pinching solutions of slender cylindrical jets

    Science.gov (United States)

    Papageorgiou, Demetrios T.; Orellana, Oscar

    1993-01-01

    Simplified equations for slender jets are derived for a circular jet of one fluid flowing into an ambient second fluid, the flow being confined in a circular tank. Inviscid flows are studied which include both surface tension effects and Kelvin-Helmholtz instability. For slender jets a coupled nonlinear system of equations is found for the jet shape and the axial velocity jump across it. The equations can break down after a finite time and similarity solutions are constructed, and studied analytically and numerically. The break-ups found pertain to the jet pinching after a finite time, without violation of the slender jet ansatz. The system is conservative and admissible singular solutions are those which conserve the total energy, mass, and momentum. Such solutions are constructed analytically and numerically, and in the case of vortex sheets with no surface tension certain solutions are given in closed form.

  14. Jet impact on a soap film.

    Science.gov (United States)

    Kirstetter, Geoffroy; Raufaste, Christophe; Celestini, Franck

    2012-09-01

    We experimentally investigate the impact of a liquid jet on a soap film. We observe that the jet never breaks the film and that two qualitatively different steady regimes may occur. The first one is a refractionlike behavior obtained at small incidence angles when the jet crosses the film and is deflected by the film-jet interaction. For larger incidence angles, the jet is absorbed by the film, giving rise to a new class of flows in which the jet undulates along the film with a characteristic wavelength. Besides its fundamental interest, this paper presents a different way to guide a micrometric flow of liquid in the inertial regime and to probe foam stability submitted to violent perturbations at the soap film scale.

  15. Tagging Partially Reconstructed Objects with Jet Substructure

    CERN Document Server

    Freytsis, Marat; Walsh, Jonathan R

    2014-01-01

    We present a new tagger which aims at identifying partially reconstructed objects, in which only some of the constituents are collected in a single jet. As an example, we focus on top decays in which either part of the hadronically decaying W or the b jet is soft or falls outside of the top jet cone. We construct an observable to identify remnant substructure from the decay and employ aggressive jet grooming to reject QCD backgrounds. The tagger is complementary to existing ones and works well in the intermediate boost regime where jet substructure techniques usually fail. It is anticipated that a similar tagger can be used to identify non-QCD hadronic jets, such as those expected from hidden valleys.

  16. Combining resummed Higgs predictions across jet bins

    Energy Technology Data Exchange (ETDEWEB)

    Boughezal, Radja [Argonne National Laboratory, IL (United States). High Energy Physics Division; Liu, Xiaohui; Petriello, Frank [Argonne National Laboratory, IL (United States). High Energy Physics Division; Northwestern Univ., Evanston, IL (United States). Dept. of Physics and Astronomy; Tackmann, Frank J. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Walsh, Jonathan R. [California Univ., Berkeley, CA (United States). Ernest Orlando Lawrence Berkeley Laboratory; California Univ., Berkeley, CA (United States). Center for Theoretical Physics

    2013-12-15

    Experimental analyses often use jet binning to distinguish between different kinematic regimes and separate contributions from background processes. To accurately model theoretical uncertainties in these measurements, a consistent description of the jet bins is required. We present a complete framework for the combination of resummed results for production processes in different exclusive jet bins, focusing on Higgs production in gluon fusion as an example. We extend the resummation of the H+1-jet cross section into the challenging low transverse momentum region, lowering the uncertainties considerably. We provide combined predictions with resummation for cross sections in the H+0-jet and H+1-jet bins, and give an improved theory covariance matrix for use in experimental studies. We estimate that the relevant theoretical uncertainties on the signal strength in the H{yields}WW{sup *} analysis are reduced by nearly a factor of 2 compared to the current value.

  17. Effective Field Theory for Jet Processes.

    Science.gov (United States)

    Becher, Thomas; Neubert, Matthias; Rothen, Lorena; Shao, Ding Yu

    2016-05-13

    Processes involving narrow jets receive perturbative corrections enhanced by logarithms of the jet opening angle and the ratio of the energies inside and outside the jets. Analyzing cone-jet processes in effective field theory, we find that in addition to soft and collinear fields their description requires degrees of freedom that are simultaneously soft and collinear to the jets. These collinear-soft particles can resolve individual collinear partons, leading to a complicated multi-Wilson-line structure of the associated operators at higher orders. Our effective field theory provides, for the first time, a factorization formula for a cone-jet process, which fully separates the physics at different energy scales. Its renormalization-group equations control all logarithmically enhanced higher-order terms, in particular also the nonglobal logarithms.

  18. Jet measurements by ALICE at LHC

    Energy Technology Data Exchange (ETDEWEB)

    Sultanov, Rishat, E-mail: rishat.sultanov@cern.ch [National Research Centre Kurchatov Institute, Alikhanov Institute for Theoretical and Experimental Physics (Russian Federation); Collaboration: ALICE Collaboration

    2015-12-15

    Jets are collimated sprays of particles originating from fragmentation of high energy partons produced in a hard collision. They are an important diagnostic tool in studies of the Quark Gluon Plasma (QGP). The modification of the jet fragmentation pattern and its structure is a signature for the influence of hot and dense matter on the parton fragmentation process. Jet measurements in proton-proton collisions provide a baseline for similar measurements in heavy-ion collisions, while studies in proton-nucleus system allow to estimate cold nuclear matter effects. Here we present jet studies in different colliding systems (p–p, p–Pb, Pb–Pb) performed by the ALICE collaboration at LHC energies. Results on jet spectra, cross sections, nuclear modification factors, jet structure and other kinematic observables will be presented.

  19. Solar Coronal Jets: Observations, Theory, and Modeling

    CERN Document Server

    Raouafi, N E; Pariat, E; Young, P R; Sterling, A C; Savcheva, A; Shimojo, M; Moreno-Insertis, F; DeVore, C R; Archontis, V; Török, T; Mason, H; Curdt, W; Meyer, K; Dalmasse, K; Matsui, Y

    2016-01-01

    Coronal jets represent important manifestations of ubiquitous solar transients, which may be the source of significant mass and energy input to the upper solar atmosphere and the solar wind. While the energy involved in a jet-like event is smaller than that of "nominal" solar flares and coronal mass ejections (CMEs), jets share many common properties with these phenomena, in particular, the explosive magnetically driven dynamics. Studies of jets could, therefore, provide critical insight for understanding the larger, more complex drivers of the solar activity. On the other side of the size-spectrum, the study of jets could also supply important clues on the physics of transients close or at the limit of the current spatial resolution such as spicules. Furthermore, jet phenomena may hint to basic process for heating the corona and accelerating the solar wind; consequently their study gives us the opportunity to attack a broad range of solar-heliospheric problems.

  20. Whipping Instabilities in Electrified Liquid Jets

    CERN Document Server

    Marin, Alvaro G; Loscertales, Ignacio G; Barrero, Antonio

    2008-01-01

    A liquid jet may develop different types of instabilities, like the so-called Rayleigh-Plateau instability, which breaks the jet into droplets. However, another type of instabilities may appear when we electrify a liquid jet and induce some charge at his surface. Among them, the most common is the so-called Whipping Instability, which is characterized by violent and fast lashes of the jet. In the submitted fluid dynamic video(see http://hdl.handle.net/1813/11422), we will show an unstable charged glycerine jet in a dielectric liquid bath, which permits an enhanced visualization of the instability. For this reason, it is probably the first time that these phenomena are visualized with enough clarity to analyze features as the effect of the feeding liquid flow rate through the jet or as the surprising spontaneous stabilization at some critical distance to the ground electrode.