WorldWideScience

Sample records for poynting dominated jets

  1. ASYMPTOTIC STRUCTURE OF POYNTING-DOMINATED JETS

    International Nuclear Information System (INIS)

    Lyubarsky, Yuri

    2009-01-01

    In relativistic, Poynting-dominated outflows, acceleration and collimation are intimately connected. An important point is that the Lorentz force is nearly compensated by the electric force; therefore the acceleration zone spans a large range of scales. We derived the asymptotic equations describing relativistic, axisymmetric magnetohydrodynamic flows far beyond the light cylinder. These equations do not contain either intrinsic small scales (like the light cylinder radius) or terms that nearly cancel each other (like the electric and magnetic forces); therefore they could be easily solved numerically. They also suit well for qualitative analysis of the flow and, in many cases, they could even be solved analytically or semianalytically. We show that there are generally two collimation regimes. In the first regime, the residual of the hoop stress and the electric force is counterbalanced by the pressure of the poloidal magnetic field so that, at any distance from the source, the structure of the flow is the same as the structure of an appropriate cylindrical equilibrium configuration. In the second regime, the pressure of the poloidal magnetic field is negligibly small so that the flow could be conceived as composed from coaxial magnetic loops. In the two collimation regimes, the flow is accelerated in different ways. We study in detail the structure of jets confined by the external pressure with a power-law profile. In particular, we obtained simple scalings for the extent of the acceleration zone, for the terminal Lorentz factor, and for the collimation angle.

  2. Transmission line analogy for relativistic Poynting-flux jets

    Science.gov (United States)

    Lovelace, R. V. E.; Kronberg, P. P.

    2013-04-01

    Radio emission, polarization and Faraday rotation maps of the radio jet of the galaxy 3C 303 have shown that one knot of this jet carries a galactic-scale electric current and that it is magnetically dominated. We develop the theory of magnetically dominated or Poynting-flux jets by making an analogy of a Poynting jet with a transmission line or waveguide carrying a net current and having a potential drop across it (from the jet's axis to its radius) and a definite impedance which we derive. The electromagnetic energy flow in the jet is the jet impedance times the square of the jet current. The observed current in 3C 303 can be used to calculate the electromagnetic energy flow in this magnetically dominated jet. Time dependent but not necessarily small perturbations of a Poynting-flux jet are described by the `telegrapher's equations'. These predict the propagation speed of disturbances and the effective wave impedance for forward and backward propagating wave components. A localized disturbance of a Poynting jet gives rise to localized dissipation in the jet which may explain the enhanced synchrotron radiation in the knots of the 3C 303 jet, and also in the apparently stationary knot HST-1 in the jet near the nucleus of the nearby galaxy M87. For a relativistic Poynting jet on parsec scales, the reflected voltage wave from an inductive termination or load can lead to a backward propagating wave which breaks down the magnetic insulation of the jet giving |{boldsymbol E}| /|{boldsymbol B}|ge 1. At the threshold for breakdown, |{boldsymbol E}|/|{boldsymbol B}|=1, positive and negative particles are directly accelerated in the {boldsymbol E} × {boldsymbol B} direction which is approximately along the jet axis. Acceleration can occur up to Lorentz factors ˜107. This particle acceleration mechanism is distinct from that in shock waves and that in magnetic field reconnection.

  3. EVOLUTION OF RELATIVISTIC PLASMOID CHAINS IN A POYNTING-DOMINATED PLASMA

    International Nuclear Information System (INIS)

    Takamoto, Makoto

    2013-01-01

    In this paper, we investigate the evolution of plasmoid chains in a Poynting-dominated plasma. We model the relativistic current sheet with a cold background plasma using the relativistic resistive magnetohydrodynamic approximation and solve for its temporal evolution numerically. We perform various calculations using different magnetization parameters of the background plasma and different Lundquist numbers. Numerical results show that the initially induced plasmoid triggers a secondary tearing instability, which gradually fills the current sheet with plasmoids, as has also been observed in the non-relativistic case. We find that plasmoid chains greatly enhance the reconnection rate, which becomes independent of the Lundquist number when the Lundquist number exceeds a critical value. In addition, we show that the distribution of plasmoid size becomes a power law. Since magnetic reconnection is expected to play an important role in various high-energy astrophysical phenomena, our results can be used for explaining the physical mechanisms of those phenomena

  4. Rotating electrical machines: Poynting flow

    International Nuclear Information System (INIS)

    Donaghy-Spargo, C

    2017-01-01

    This paper presents a complementary approach to the traditional Lorentz and Faraday approaches that are typically adopted in the classroom when teaching the fundamentals of electrical machines—motors and generators. The approach adopted is based upon the Poynting vector, which illustrates the ‘flow’ of electromagnetic energy. It is shown through simple vector analysis that the energy-flux density flow approach can provide insight into the operation of electrical machines and it is also shown that the results are in agreement with conventional Maxwell stress-based theory. The advantage of this approach is its complementary completion of the physical picture regarding the electromechanical energy conversion process—it is also a means of maintaining student interest in this subject and as an unconventional application of the Poynting vector during normal study of electromagnetism. (paper)

  5. Poynting's theorem for complex fields; El teorema de Poynting para campos complejos

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez Guasti, M. [Universidad Autonoma Metropolitana-Unidad Iztapalapa, Mexico, D.F (Mexico)

    2001-04-01

    Poynting's theorem is derived for complex electromagnetic fields without invoking the harmonic dependence of the fields. This reformulation yields the functional form of a continuity equation. The definition of poynting's vector for complex fields reduces to its traditional definition for real fields without involving an extra factor of 1/2. [Spanish] Se presenta la derivacion del teorema de Poynting utilizando una representacion compleja de los campos electromagneticos. En esta reformulacion se obtiene cabalmente la forma funcional de una ecuacion de continuidad. Este resultado no requiere que los campos armonicos sean trenes de onda infinitos, de manera que con este formalismo es posible abordar el caso de pulsos electromagneticos. La definicion del vector Poynting para campos complejos se reduce a la definicion convencional si los campos son reales sin involucrar un factor de 1/2 adicional.

  6. The Composition of GRB Jets and the ICMART Model

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Bing [University of Nevada, Las Vegas; Guo, Fan [Los Alamos National Laboratory

    2015-07-16

    Models of gamma ray bursts (GRBs) are drawn from observations of light curves, spectra, and spectral evolution. The ICMART (Internal Collision-induced MAgnetic Reconnection & Turbulence) model and some of its features are presented. Increasing evidence points towards Poynting-flux-dominated jets in at least some (even a good fraction of) GRBs. The main emission component (Band) is of a synchrotron emission origin, produced by electrons accelerated in the emission region. The data seem to require that magnetic reconnection in the moderately-high sigma regime is the mechanism to accelerate particles. Extensive numerical simulations are needed to verify physical details of such a model, and some encouraging results have been obtained.

  7. VLBA AND CHANDRA OBSERVATIONS OF JETS IN FRI RADIO GALAXIES: CONSTRAINTS ON JET EVOLUTION

    International Nuclear Information System (INIS)

    Kharb, P.; O'Dea, C. P.; Tilak, A.; Baum, S. A.; Haynes, E.; Noel-Storr, J.; Fallon, C.; Christiansen, K.

    2012-01-01

    We present here the results from new Very Long Baseline Array (VLBA) observations at 1.6 and 5 GHz of 19 galaxies of a complete sample of 21 Uppasala General Catalog (UGC) Fanaroff-Riley type I (FRI) radio galaxies. New Chandra data of two sources, viz., UGC 00408 and UGC 08433, are combined with the Chandra archival data of 13 sources. The 5 GHz observations of 10 'core-jet' sources are polarization-sensitive, while the 1.6 GHz observations constitute second-epoch total intensity observations of nine 'core-only' sources. Polarized emission is detected in the jets of seven sources at 5 GHz, but the cores are essentially unpolarized, except in M87. Polarization is detected at the jet edges in several sources, and the inferred magnetic field is primarily aligned with the jet direction. This could be indicative of magnetic field 'shearing' due to jet-medium interaction, or the presence of helical magnetic fields. The jet peak intensity I ν falls with distance d from the core, following the relation, I ν ∝d a , where a is typically ∼ – 1.5. Assuming that adiabatic expansion losses are primarily responsible for the jet intensity 'dimming,' two limiting cases are considered: (1) the jet has a constant speed on parsec scales and is expanding gradually such that the jet radius r∝d 0 .4 ; this expansion is, however, unobservable in the laterally unresolved jets at 5 GHz, and (2) the jet is cylindrical and is accelerating on parsec scales. Accelerating parsec-scale jets are consistent with the phenomenon of 'magnetic driving' in Poynting-flux-dominated jets. While slow jet expansion as predicted by case (1) is indeed observed in a few sources from the literature that are resolved laterally, on scales of tens or hundreds of parsecs, case (2) cannot be ruled out in the present data, provided the jets become conical on scales larger than those probed by VLBA. Chandra observations of 15 UGC FRIs detect X-ray jets in 9 of them. The high frequency of occurrence of X

  8. Jet launching radius in low-power radio-loud AGNs in advection-dominated accretion flows

    Science.gov (United States)

    Le, Truong; Newman, William; Edge, Brinkley

    2018-06-01

    Using our theory for the production of relativistic outflows, we estimate the jet launching radius and the inferred mass accretion rate for 52 low-power radio-loud AGNs based on the observed jet powers. Our analysis indicates that (1) a significant fraction of the accreted energy is required to convert the accreted mass to relativistic energy particles for the production of the jets near the event horizon, (2) the jet's launching radius moves radially towards the horizon as the mass accretion rate or jet's power increases, and (3) no jet/outflow formation is possible beyond 44 gravitational radii.

  9. Polarization and Structure of Relativistic Parsec-Scale AGN Jets

    International Nuclear Information System (INIS)

    Lyutikov, M

    2004-01-01

    mildly relativistic jets, when a counter jet can be seen, the polarization of the counter jet is preferentially orthogonal to the axis, unless the jet is strongly dominated by the toroidal magnetic field in its rest frame. (6) For resolved jets, the polarization pattern is not symmetric with respect to jet axis. Under certain conditions, this can be used to deduce the direction of the spin of the central object (black hole or disk), whether it is aligned or anti-aligned with the jet axis. (7) In resolved ''cylindrical shell'' type jets, the central parts of the jet are polarized along the axis, while the outer parts are polarized orthogonal to it, in accordance with observations. We conclude that large-scale magnetic fields can explain the salient polarization properties of parsec-scale AGN jets. Since the typical degrees of polarization are (le) 15%, the emitting parts of the jets must have comparable rest-frame toroidal and poloidal fields. In this case, most relativistic jets are strongly dominated by the toroidal magnetic field component in the observer's frame, B φ /B z ∼ Λ. We also discuss the possibility that relativistic AGN jets may be electromagnetically (Poynting flux) dominated. In this case, dissipation of the toroidal magnetic field (and not fluid shocks) may be responsible for particle acceleration

  10. The effects of Poynting-Robertson drag on solar sails

    Science.gov (United States)

    Abd El-Salam, F. A.

    2018-06-01

    In the present work, the concept of solar sailing and its developing spacecraft are presented. The effects of Poynting-Robertson drag on solar sails are considered. Some analytical control laws with some mentioned input constraints for optimizing solar sails dynamics in heliocentric orbit using Lagrange's planetary equations are obtained. Optimum force vector in a required direction is maximized by deriving optimal sail cone angle. New control laws that maximize thrust to obtain certain required maximization in some particular orbital element are obtained.

  11. JET RF dominated scenarios and ion ITB experiments with low external momentum input

    International Nuclear Information System (INIS)

    Crisanti, F.; Esposito, B.; Gormezano, C.; Buratti, P.; Cardinali, A.; Giovannozzi, E.; Sozzi, C.; Becoulet, A.; Rimini, F.; Garbet, X.; Guirlet, R.; Joffrin, E.; Litaudon, X.; Brambilla, M.; Baar, M. de; Luna, E. de la; Vries, P. de; Giroud, C.; Mantica, P.; Mantsinen, M.; Salmi, A.; Eester, D. van

    2005-01-01

    Advanced Tokamak scenarios include two different regimes: the 'steady state' (characterized by the presence of an Internal Transport Barrier (ITB)) and the 'hybrid scenario' (characterized by central q > 1 and a large region with magnetic shear close to zero). So far both the regimes, at least for the ion species, have always been obtained in presence of strong injection of external momentum by Neutrals Beam Injection (NBI) heating. By using Lower Hybrid Current Drive (LHCD) to sustain the central q slightly above one and with a large plasma region having the magnetic shear s close to zero, an 'hybrid scenario' has been established, for the first time, in discharges with dominant Ion Cyclotron Resonance Heating (ICRH) and with a normalized beta close to two. By starting from a configuration with reversed magnetic shear (sustained only by LHCD) and with a well established ITB on the electron species, an ITB also on the ions species has been obtained by using ICRH in an ion minority heating scheme, ( 3 He)D. No external momentum input was provided by the NBI, except for the diagnostic charge-exchange and the MSE beams. In these discharges the evaluated ExB shearing rate was always very small (in the noisy range) and lower than analytical evaluations of the turbulence growth rate. (author)

  12. GEM-CEDAR Challenge: Poynting Flux at DMSP and Modeled Joule Heat

    Science.gov (United States)

    Rastaetter, Lutz; Shim, Ja Soon; Kuznetsova, Maria M.; Kilcommons, Liam M.; Knipp, Delores J.; Codrescu, Mihail; Fuller-Rowell, Tim; Emery, Barbara; Weimer, Daniel R.; Cosgrove, Russell; hide

    2016-01-01

    Poynting flux into the ionosphere measures the electromagnetic energy coming from the magnetosphere. This energy flux can vary greatly between quiet times and geomagnetic active times. As part of the Geospace Environment Modeling-coupling energetics and dynamics of atmospheric regions modeling challenge, physics-based models of the 3-D ionosphere and ionospheric electrodynamics solvers of magnetosphere models that specify Joule heat and empirical models specifying Poynting flux were run for six geomagnetic storm events of varying intensity. We compared model results with Poynting flux values along the DMSP-15 satellite track computed from ion drift meter and magnetic field observations. Although being a different quantity, Joule heat can in practice be correlated to incoming Poynting flux because the energy is dissipated primarily in high latitudes where Poynting flux is being deposited. Within the physics-based model group, we find mixed results with some models overestimating Joule heat and some models agreeing better with observed Poynting flux rates as integrated over auroral passes. In contrast, empirical models tend to underestimate integrated Poynting flux values. Modeled Joule heat or Poynting flux patterns often resemble the observed Poynting flux patterns on a large scale, but amplitudes can differ by a factor of 2 or larger due to the highly localized nature of observed Poynting flux deposition that is not captured by the models. In addition, the positioning of modeled patterns appear to be randomly shifted against the observed Poynting flux energy input. This study is the first to compare Poynting flux and Joule heat in a large variety of models of the ionosphere.

  13. Experimental study of the emergence of two-jet dominance in pp collisions at √s = 630 GeV

    DEFF Research Database (Denmark)

    Appel, J.A.; Bagnaia, P.; Banner, M.

    1985-01-01

    A heuristic model is used to describe data collected by the UA2 experiment at √s = 630 GeV. Distributions of the energy sharing between the leading clusters and the rest of the event are examined. The main features of these distributions can be described by a two-component model with soft, collec......, collective interactions dominating at low transverse energy and hard, constituent interactions dominating at high transverse energy. This model provides a simple picture of the emergence of two-jet dominance at SPS pp Collider energies....

  14. Lagrangian formulation of the general relativistic Poynting-Robertson effect

    Science.gov (United States)

    De Falco, Vittorio; Battista, Emmanuele; Falanga, Maurizio

    2018-04-01

    We propose the Lagrangian formulation for describing the motion of a test particle in a general relativistic, stationary, and axially symmetric spacetime. The test particle is also affected by a radiation field, modeled as a coherent flux of photons traveling along the null geodesics of the background spacetime, including the general relativistic Poynting-Robertson effect. The innovative part of this work is to prove the existence of the potential linked to the dissipative action caused by the Poynting-Robertson effect in general relativity through the help of an integrating factor, depending on the energy of the system. Generally, such kinds of inverse problems involving dissipative effects might not admit a Lagrangian formulation; especially, in general relativity, there are no examples of such attempts in the literature so far. We reduce this general relativistic Lagrangian formulation to the classic case in the weak-field limit. This approach facilitates further studies in improving the treatment of the radiation field, and it contains, for example, some implications for a deeper comprehension of the gravitational waves.

  15. Positive or negative Poynting effect? The role of adscititious inequalities in hyperelastic materials

    KAUST Repository

    Mihai, L. A.

    2011-08-10

    Motivated by recent experiments on biopolymer gels whereby the reverse of the usual (positive) Poynting effect was observed, we investigate the effect of the so-called \\'adscititious inequalities\\' on the behaviour of hyperelastic materials subject to shear. We first demonstrate that for homogeneous isotropic materials subject to pure shear, the resulting deformation consists of a triaxial stretch combined with a simple shear in the direction of the shear force if and only if the Baker-Ericksen inequalities hold. Then for a cube deformed under pure shear, the positive Poynting effect occurs if the \\'sheared faces spread apart\\', whereas the negative Poynting effect is obtained if the \\'sheared faces draw together\\'. Similarly, under simple shear deformation, the positive Poynting effect is obtained if the \\'sheared faces tend to spread apart\\', whereas the negative Poynting effect occurs if the \\'sheared faces tend to draw together\\'. When the Poynting effect occurs under simple shear, it is reasonable to assume that the same sign Poynting effect is btained also under pure shear. Since the observation of the negative Poynting effect in semiflexible biopolymers implies that the (stronger) empirical inequalities may not hold, we conclude that these inequalities must not be imposed when such materials are described. © 2011 The Royal Society.

  16. SPATIAL GROWTH OF CURRENT-DRIVEN INSTABILITY IN RELATIVISTIC ROTATING JETS AND THE SEARCH FOR MAGNETIC RECONNECTION

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Chandra B.; Pino, Elisabete M. de Gouveia Dal [Department of Astronomy (IAG-USP), University of São Paulo, São Paulo (Brazil); Mizuno, Yosuke, E-mail: csingh@iag.usp.br, E-mail: dalpino@iag.usp.br, E-mail: mizuno@th.physik.uni-frankfurt.de [Institute for Theoretical Physics, Goethe University, D-60438, Frankfurt am Main (Germany)

    2016-06-10

    Using the three-dimensional relativistic magnetohydrodynamic code RAISHIN, we investigated the influence of the radial density profile on the spatial development of the current-driven kink instability along magnetized rotating, relativistic jets. For the purposes of our study, we used a nonperiodic computational box, the jet flow is initially established across the computational grid, and a precessional perturbation at the inlet triggers the growth of the kink instability. We studied light and heavy jets with respect to the environment depending on the density profile. Different angular velocity amplitudes have been also tested. The results show the propagation of a helically kinked structure along the jet and a relatively stable configuration for the lighter jets. The jets appear to be collimated by the magnetic field, and the flow is accelerated owing to conversion of electromagnetic into kinetic energy. We also identify regions of high current density in filamentary current sheets, indicative of magnetic reconnection, which are associated with the kink-unstable regions and correlated with the decrease of the sigma parameter of the flow. We discuss the implications of our findings for Poynting-flux-dominated jets in connection with magnetic reconnection processes. We find that fast magnetic reconnection may be driven by the kink-instability turbulence and govern the transformation of magnetic into kinetic energy, thus providing an efficient way to power and accelerate particles in active galactic nucleus and gamma-ray-burst relativistic jets.

  17. Helicons in uniform fields. II. Poynting vector and angular momenta

    Science.gov (United States)

    Stenzel, R. L.; Urrutia, J. M.

    2018-03-01

    The orbital and spin angular momenta of helicon modes have been determined quantitatively from laboratory experiments. The current density is obtained unambiguously from three dimensional magnetic field measurements. The only approximation made is to obtain the electric field from Hall Ohm's law which is usually the case for low frequency whistler modes. This allows the evaluation of the Poynting vector from which the angular momentum is obtained. Comparing two helicon modes (m = 0 and m = 1), one can separate the contribution of angular momentum of a rotating and non-rotating wave field. The orbital angular momentum is important to assess the wave-particle interaction by the transverse Doppler shift of rotating waves which has not been considered so far.

  18. Relativistic jets without large-scale magnetic fields

    Science.gov (United States)

    Parfrey, K.; Giannios, D.; Beloborodov, A.

    2014-07-01

    The canonical model of relativistic jets from black holes requires a large-scale ordered magnetic field to provide a significant magnetic flux through the ergosphere--in the Blandford-Znajek process, the jet power scales with the square of the magnetic flux. In many jet systems the presence of the required flux in the environment of the central engine is questionable. I will describe an alternative scenario, in which jets are produced by the continuous sequential accretion of small magnetic loops. The magnetic energy stored in these coronal flux systems is amplified by the differential rotation of the accretion disc and by the rotating spacetime of the black hole, leading to runaway field line inflation, magnetic reconnection in thin current layers, and the ejection of discrete bubbles of Poynting-flux-dominated plasma. For illustration I will show the results of general-relativistic force-free electrodynamic simulations of rotating black hole coronae, performed using a new resistivity model. The dissipation of magnetic energy by coronal reconnection events, as demonstrated in these simulations, is a potential source of the observed high-energy emission from accreting compact objects.

  19. The Poynting vector of a charged magnetic dipole: two limiting cases

    Energy Technology Data Exchange (ETDEWEB)

    Sod-Hoffs, J; Manko, V S [Departamento de Fisica, Centro de Investigacion y de Estudios Avanzados del I.P.N., A.P. 14-740, 07000 Mexico D.F. (Mexico)

    2007-11-15

    We consider the Poynting vector of two exact solutions describing a charged magnetized non-rotating mass in the following limiting cases: (i) m{sup 2} = q{sup 2}, and (ii) m = 0. Whereas the former limit leads to a non-vanishing Poynting vector only for one of the solutions, the latter limit in both solutions results in non-zero expressions of the azimuthal component of the Poynting vector, thus providing evidence that Bonnor's frame-dragging effect takes place even in the case of a charged massless magnetic dipole.

  20. Positive or negative Poynting effect? The role of adscititious inequalities in hyperelastic materials

    KAUST Repository

    Mihai, L. A.; Goriely, A.

    2011-01-01

    Motivated by recent experiments on biopolymer gels whereby the reverse of the usual (positive) Poynting effect was observed, we investigate the effect of the so-called 'adscititious inequalities' on the behaviour of hyperelastic materials subject

  1. Boosting jet power in black hole spacetimes.

    Science.gov (United States)

    Neilsen, David; Lehner, Luis; Palenzuela, Carlos; Hirschmann, Eric W; Liebling, Steven L; Motl, Patrick M; Garrett, Travis

    2011-08-02

    The extraction of rotational energy from a spinning black hole via the Blandford-Znajek mechanism has long been understood as an important component in models to explain energetic jets from compact astrophysical sources. Here we show more generally that the kinetic energy of the black hole, both rotational and translational, can be tapped, thereby producing even more luminous jets powered by the interaction of the black hole with its surrounding plasma. We study the resulting Poynting jet that arises from single boosted black holes and binary black hole systems. In the latter case, we find that increasing the orbital angular momenta of the system and/or the spins of the individual black holes results in an enhanced Poynting flux.

  2. EVIDENCE OF THE DYNAMICS OF RELATIVISTIC JET LAUNCHING IN QUASARS

    Energy Technology Data Exchange (ETDEWEB)

    Punsly, Brian, E-mail: brian.punsly1@verizon.net [1415 Granvia Altamira, Palos Verdes Estates CA, USA 90274 and ICRANet, Piazza della Repubblica 10 Pescara I-65100 (Italy)

    2015-06-10

    Hubble Space Telescope (HST) spectra of the EUV, the optically thick emission from the innermost accretion flow onto the central supermassive black hole, indicate that radio loud quasars (RLQs) tend to be EUV weak compared to the radio-quiet quasars; yet the remainder of the optically thick thermal continuum is indistinguishable. The deficit of EUV emission in RLQs has a straightforward interpretation as a missing or a suppressed innermost region of local energy dissipation in the accretion flow. This article is an examination of the evidence for a distribution of magnetic flux tubes in the innermost accretion flow that results in magnetically arrested accretion (MAA) and creates the EUV deficit. These same flux tubes and possibly the interior magnetic flux that they encircle are the sources of the jet power as well. In the MAA scenario, islands of large-scale vertical magnetic flux perforate the innermost accretion flow of RLQs. The first prediction of the theory that is supported by the HST data is that the strength of the (large-scale poloidal magnetic fields) jets in the MAA region is regulated by the ram pressure of the accretion flow in the quasar environment. The second prediction that is supported by the HST data is that the rotating magnetic islands remove energy from the accretion flow as a Poynting flux dominated jet in proportion to the square of the fraction of the EUV emitting gas that is displaced by these islands.

  3. Poynting flux measurements on a satellite: A diagnostic tool for space research

    International Nuclear Information System (INIS)

    Kelley, M.C.; Knudsen, D.J.; Vickery, J.F.

    1991-01-01

    The first satellite observations of the total field-aligned component of the quasi-dc Poynting flux are presented for two passes over the polar region, one in the noon sector and one in the afternoon. The energy input due to electron precipitation is also presented. In the noon pass the downward Poynting flux in the auroral oval was comparable to the kinetic energy input rate. The peak electromagnetic energy input rate of 6 ergs/(cm 2 s) equaled the peak particle input while the integrated electromagnetic value along the trajectory was 60% that of the particles. In the afternoon pass the peak electromagnetic energy input was also about 6 ergs/(cm 2 s), but the peak particle energy was 6 times this value. The average electromagnetic input was 10% of the particle input for the pass. In this study, the authors can measure the Poynting flux only over a limited range of scale sizes; thus the contribution to the total energy budget in the polar cap cannot be determined. Both passes show small regions characterized by upward Poynting flux suggesting a neutral wind dynamo. There is also evidence during part of the noontime pass that the external generator acted in opposition to an existing wind field since the Poynting flux was greater than the estimate of Joule heating from the electric field measurement alone (i.e., from Σ p E 2 ). In the course of deriving Poynting's theorem for the geophysical case they also present a proof that ground magnetometer systems respond primarily to the Hall current which does not depend upon geometric cancellation between the field generated by Pedersen and field-aligned currents

  4. STUDY OF THE POYNTING FLUX IN ACTIVE REGION 10930 USING DATA-DRIVEN MAGNETOHYDRODYNAMIC SIMULATION

    International Nuclear Information System (INIS)

    Fan, Y. L.; Wang, H. N.; He, H.; Zhu, X. S.

    2011-01-01

    Powerful solar flares are closely related to the evolution of magnetic field configuration on the photosphere. We choose the Poynting flux as a parameter in the study of magnetic field changes. We use time-dependent multidimensional MHD simulations around a flare occurrence to generate the results, with the temporal variation of the bottom boundary conditions being deduced from the projected normal characteristic method. By this method, the photospheric magnetogram could be incorporated self-consistently as the bottom condition of data-driven simulations. The model is first applied to a simulation datum produced by an emerging magnetic flux rope as a test case. Then, the model is used to study NOAA AR 10930, which has an X3.4 flare, the data of which has been obtained by the Hinode/Solar Optical Telescope on 2006 December 13. We compute the magnitude of Poynting flux (S total ), radial Poynting flux (S z ), a proxy for ideal radial Poynting flux (S proxy ), Poynting flux due to plasma surface motion (S sur ), and Poynting flux due to plasma emergence (S emg ) and analyze their extensive properties in four selected areas: the whole sunspot, the positive sunspot, the negative sunspot, and the strong-field polarity inversion line (SPIL) area. It is found that (1) the S total , S z , and S proxy parameters show similar behaviors in the whole sunspot area and in the negative sunspot area. The evolutions of these three parameters in the positive area and the SPIL area are more volatile because of the effect of sunspot rotation and flux emergence. (2) The evolution of S sur is largely influenced by the process of sunspot rotation, especially in the positive sunspot. The evolution of S emg is greatly affected by flux emergence, especially in the SPIL area.

  5. On the electromagnetic fields, Poynting vector, and peak power radiated by lightning return strokes

    Science.gov (United States)

    Krider, E. P.

    1992-01-01

    The initial radiation fields, Poynting vector, and total electromagnetic power that a vertical return stroke radiates into the upper half space have been computed when the speed of the stroke, nu, is a significant fraction of the speed of light, c, assuming that at large distances and early times the source is an infinitesimal dipole. The initial current is also assumed to satisfy the transmission-line model with a constant nu and to be perpendicular to an infinite, perfectly conducting ground. The effect of a large nu is to increase the radiation fields by a factor of (1-beta-sq cos-sq theta) exp -1, where beta = nu/c and theta is measured from the vertical, and the Poynting vector by a factor of (1-beta-sq cos-sq theta) exp -2.

  6. Non-overlapped P- and S-wave Poynting vectors and its solution on Grid Method

    KAUST Repository

    Lu, Yong Ming; Liu, Qiancheng

    2017-01-01

    Poynting vector represents the local directional energy flux density of seismic waves in geophysics. It is widely used in elastic reverse time migration (RTM) to analyze source illumination, suppress low-wavenumber noise, correct for image polarity and extract angle-domain common imaging gather (ADCIG). However, the P and S waves are mixed together during wavefield propagation such that the P and S energy fluxes are not clean everywhere, especially at the overlapped points. In this paper, we use a modified elastic wave equation in which the P and S vector wavefields are naturally separated. Then, we develop an efficient method to evaluate the separable P and S poynting vectors, respectively, based on the view that the group velocity and phase velocity have the same direction in isotropic elastic media. We furthermore formulate our method using an unstructured mesh based modeling method named the grid method. Finally, we verify our method using two numerical examples.

  7. Non-overlapped P- and S-wave Poynting vectors and its solution on Grid Method

    KAUST Repository

    Lu, Yong Ming

    2017-12-12

    Poynting vector represents the local directional energy flux density of seismic waves in geophysics. It is widely used in elastic reverse time migration (RTM) to analyze source illumination, suppress low-wavenumber noise, correct for image polarity and extract angle-domain common imaging gather (ADCIG). However, the P and S waves are mixed together during wavefield propagation such that the P and S energy fluxes are not clean everywhere, especially at the overlapped points. In this paper, we use a modified elastic wave equation in which the P and S vector wavefields are naturally separated. Then, we develop an efficient method to evaluate the separable P and S poynting vectors, respectively, based on the view that the group velocity and phase velocity have the same direction in isotropic elastic media. We furthermore formulate our method using an unstructured mesh based modeling method named the grid method. Finally, we verify our method using two numerical examples.

  8. Survey of Poynting flux of whistler mode chorus in the outer zone

    Czech Academy of Sciences Publication Activity Database

    Santolík, Ondřej; Pickett, J. S.; Gurnett, D. A.; Menietti, J. D.; Tsurutani, B. T.; Verkhoglyadova, O.

    2010-01-01

    Roč. 115, - (2010), A00F13/1-A00F13/13 ISSN 0148-0227 R&D Projects: GA AV ČR IAA301120601; GA ČR GA205/09/1253 Grant - others:GA MŠk(CZ) ME 842 Institutional research plan: CEZ:AV0Z30420517 Keywords : chorus * Polar spacecraft * Poynting flux Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 3.303, year: 2010

  9. Assessing the Time Dependence of Reconnection With Poynting's Theorem: MMS Observations

    Science.gov (United States)

    Genestreti, K. J.; Cassak, P. A.; Varsani, A.; Burch, J. L.; Nakamura, R.; Wang, S.

    2018-04-01

    We investigate the time dependence of electromagnetic-field-to-plasma energy conversion in the electron diffusion region of asymmetric magnetic reconnection. To do so, we consider the terms in Poynting's theorem. In a steady state there is a perfect balance between the divergence of the electromagnetic energy flux ∇·S→ and the conversion between electromagnetic field and particle energy J→·E→. This energy balance is demonstrated with a particle-in-cell simulation of reconnection. We also evaluate each of the terms in Poynting's theorem during an observation of a magnetopause reconnection region by Magnetospheric Multiscale (MMS). We take the equivalence of both sides of Poynting's theorem as an indication that the errors associated with the approximation of each term with MMS data are small. We find that, for this event, balance between J→·E→=-∇·S→ is only achieved for a small fraction of the energy conversion region at/near the X-point. Magnetic energy was rapidly accumulating on either side of the current sheet at roughly 3 times the predicted energy conversion rate. Furthermore, we find that while J→·E→>0 and ∇·S→J→·E→. We note that due to the assumptions necessary to do this calculation, the accurate evaluation of ∇·S→ may not be possible for every MMS-observed reconnection event; but, if possible, this is a simple approach to determine if reconnection is or is not in a steady state.

  10. Poynting Theorem, Relativistic Transformation of Total Energy-Momentum and Electromagnetic Energy-Momentum Tensor

    Science.gov (United States)

    Kholmetskii, Alexander; Missevitch, Oleg; Yarman, Tolga

    2016-02-01

    We address to the Poynting theorem for the bound (velocity-dependent) electromagnetic field, and demonstrate that the standard expressions for the electromagnetic energy flux and related field momentum, in general, come into the contradiction with the relativistic transformation of four-vector of total energy-momentum. We show that this inconsistency stems from the incorrect application of Poynting theorem to a system of discrete point-like charges, when the terms of self-interaction in the product {\\varvec{j}} \\cdot {\\varvec{E}} (where the current density {\\varvec{j}} and bound electric field {\\varvec{E}} are generated by the same source charge) are exogenously omitted. Implementing a transformation of the Poynting theorem to the form, where the terms of self-interaction are eliminated via Maxwell equations and vector calculus in a mathematically rigorous way (Kholmetskii et al., Phys Scr 83:055406, 2011), we obtained a novel expression for field momentum, which is fully compatible with the Lorentz transformation for total energy-momentum. The results obtained are discussed along with the novel expression for the electromagnetic energy-momentum tensor.

  11. 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...

  12. 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.

  13. Emerging jets

    International Nuclear Information System (INIS)

    Schwaller, Pedro; Stolarski, Daniel

    2015-02-01

    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. Possibilities for discovery at LHCb are also discussed.

  14. On the relativistic theory of electromagnetic dispersion relations and Poynting's theorem

    International Nuclear Information System (INIS)

    Lerche, I.

    1975-01-01

    Constitutive relations, and general dispersion relations, are derived for an arbitrary, anisotropic, dispersive and dissipative medium which is moving relative to an inertial observer. The constitutive relations are expressed in terms of the ''local'' dielectric tensor, magnetic permeability, etc., where ''local'' refers to the instantaneous rest frame of the medium. We also give the generalization of Poynting's theorem for power flow including the expression for the rate at which the moving medium does work on the radiation. In view of the current interest in radiation generated in, and passing through, pulsar magnetospheres, we believe that the general results presented here are, perhaps, not without some astrophysical import

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

    International Nuclear Information System (INIS)

    Jouttenus, Teppo T.; Stewart, Iain W.; Waalewijn, Wouter J.

    2013-02-01

    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 2 jet /p jet 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.

  16. 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.

  17. Statistics of a parallel Poynting vector in the auroral zone as a function of altitude using Polar EFI and MFE data and Astrid-2 EMMA data

    Directory of Open Access Journals (Sweden)

    P. Janhunen

    2005-07-01

    Full Text Available We study the wave-related (AC and static (DC parallel Poynting vector (Poynting energy flux as a function of altitude in auroral field lines using Polar EFI and MFE data. The study is statistical and contains 5 years of data in the altitude range 5000–30000 km. We verify the low altitude part of the results by comparison with earlier Astrid-2 EMMA Poynting vector statistics at 1000 km altitude. The EMMA data are also used to statistically compensate the Polar results for the missing zonal electric field component. We compare the Poynting vector with previous statistical DMSP satellite data concerning the electron precipitation power. We find that the AC Poynting vector (Alfvén-wave related Poynting vector is statistically not sufficient to power auroral electron precipitation, although it may, for Kp>2, power 25–50% of it. The statistical AC Poynting vector also has a stepwise transition at R=4 RE, so that its amplitude increases with increasing altitude. We suggest that this corresponds to Alfvén waves being in Landau resonance with electrons, so that wave-induced electron acceleration takes place at this altitude range, which was earlier named the Alfvén Resonosphere (ARS. The DC Poynting vector is ~3 times larger than electron precipitation and corresponds mainly to ionospheric Joule heating. In the morning sector (02:00–06:00 MLT we find that the DC Poynting vector has a nontrivial altitude profile such that it decreases by a factor of ~2 when moving upward from 3 to 4 RE radial distance. In other nightside MLT sectors the altitude profile is more uniform. The morning sector nontrivial altitude profile may be due to divergence of the perpendicular Poynting vector field at R=3–4 RE. Keywords. Magnetospheric physics (Auroral phenomena; Magnetosphere-ionosphere interactions – Space plasma physics (Wave-particle interactions

  18. A turbulent radio jet

    International Nuclear Information System (INIS)

    Kahn, F.D.

    1983-01-01

    A relativistic plasma flow can explain many of the observations on the one-sided jets, which are associated with radio sources that show superluminal motions in their cores. The pressure from the ambient medium will communicate across the jet in a relatively short distance, typically 30 kpc. The friction between the jet and the external medium then makes the flow go turbulent. As a result the jet dissipates energy and will be brought to rest within a few hundred kpc, if it does not strike an obstacle before. The mean flow in the jet is strongly sheared and stretches the lines of force of any magnetic field frozen into the plasma. The dominant field direction, as seen from the rest frame of the plasma, is therefore parallel to the length of the jet. Polarization measurements have shown that this is in fact the case. (author)

  19. 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.

  20. Numerical simulation of shear and the Poynting effects by the finite element method: An application of the generalised empirical inequalities in non-linear elasticity

    KAUST Repository

    Angela Mihai, L.; Goriely, Alain

    2013-01-01

    Finite element simulations of different shear deformations in non-linear elasticity are presented. We pay particular attention to the Poynting effects in hyperelastic materials, complementing recent theoretical findings by showing these effects

  1. The azimuthal component of Poynting's vector and the angular momentum of light

    Science.gov (United States)

    Cameron, Robert P.; Speirits, Fiona C.; Gilson, Claire R.; Allen, L.; Barnett, Stephen M.

    2015-12-01

    The usual description in basic electromagnetic theory of the linear and angular momenta of light is centred upon the identification of Poynting's vector as the linear momentum density and its cross product with position, or azimuthal component, as the angular momentum density. This seemingly reasonable approach brings with it peculiarities, however, in particular with regards to the separation of angular momentum into orbital and spin contributions, which has sometimes been regarded as contrived. In the present paper, we observe that densities are not unique, which leads us to ask whether the usual description is, in fact, the most natural choice. To answer this, we adopt a fundamental rather than heuristic approach by first identifying appropriate symmetries of Maxwell's equations and subsequently applying Noether's theorem to obtain associated conservation laws. We do not arrive at the usual description. Rather, an equally acceptable one in which the relationship between linear and angular momenta is nevertheless more subtle and in which orbital and spin contributions emerge separately and with transparent forms.

  2. The azimuthal component of Poynting's vector and the angular momentum of light

    International Nuclear Information System (INIS)

    Cameron, Robert P; Speirits, Fiona C; Barnett, Stephen M; Gilson, Claire R; Allen, L

    2015-01-01

    The usual description in basic electromagnetic theory of the linear and angular momenta of light is centred upon the identification of Poynting's vector as the linear momentum density and its cross product with position, or azimuthal component, as the angular momentum density. This seemingly reasonable approach brings with it peculiarities, however, in particular with regards to the separation of angular momentum into orbital and spin contributions, which has sometimes been regarded as contrived. In the present paper, we observe that densities are not unique, which leads us to ask whether the usual description is, in fact, the most natural choice. To answer this, we adopt a fundamental rather than heuristic approach by first identifying appropriate symmetries of Maxwell's equations and subsequently applying Noether's theorem to obtain associated conservation laws. We do not arrive at the usual description. Rather, an equally acceptable one in which the relationship between linear and angular momenta is nevertheless more subtle and in which orbital and spin contributions emerge separately and with transparent forms. (paper)

  3. Poynting vector analysis for wireless power transfer between magnetically coupled coils with different loads.

    Science.gov (United States)

    Guo, Yunsheng; Li, Jiansheng; Hou, Xiaojuan; Lv, Xiaolong; Liang, Hao; Zhou, Ji; Wu, Hongya

    2017-04-07

    Wireless power transfer is a nonradiative type of transmission that is performed in the near-field region. In this region, the electromagnetic fields that are produced by both the transmitting and receiving coils are evanescent fields, which should not transmit energy. This then raises the question of how the energy can be transferred. Here we describe a theoretical study of the two evanescent field distributions at different terminal loads. It is shown that the essential principle of wireless energy transfer is the superposition of the two evanescent fields, and the resulting superimposed field is mediated through the terminal load. If the terminal load is either capacitive or inductive, then the superimposed field cannot transfer the energy because its Poynting vector is zero; in contrast, if the load is resistive, energy can then be conveyed from the transmitting coil to the receiving coil. The simulation results for the magnetic field distributions and the time-domain current waveforms agree very well with the results of the theoretical analysis. This work thus provides a comprehensive understanding of the energy transfer mechanism involved in the magnetic resonant coupling system.

  4. A jet-dominated model for a broad-band spectral energy distribution of the nearby low-luminosity active galactic nucleus in M94

    Science.gov (United States)

    van Oers, Pieter; Markoff, Sera; Uttley, Phil; McHardy, Ian; van der Laan, Tessel; Donovan Meyer, Jennifer; Connors, Riley

    2017-06-01

    We have compiled a new multiwavelength spectral energy distribution (SED) for the closest obscured low-ionization emission-line region active galactic nucleus (AGN), NGC 4736, also known as M94. The SED comprises mainly high-resolution (mostly sub-arcsecond, or, at the distance to M94, ≲23 pc from the nucleus) observations from the literature, archival data, as well as previously unpublished sub-millimetre data from the Plateau de Bure Interferometer (PdBI) and the Combined Array for Research in Millimeter-wave Astronomy, in conjunction with new electronic MultiElement Radio Interferometric Network (e-MERLIN) L-band (1.5 GHz) observations. Thanks to the e-MERLIN resolution and sensitivity, we resolve for the first time a double structure composed of two radio sources separated by ˜1 arcsec, previously observed only at higher frequency. We explore this data set, which further includes non-simultaneous data from the Very Large Array, the Gemini telescope, the Hubble Space Telescope and the Chandra X-ray observatory, in terms of an outflow-dominated model. We compare our results with previous trends found for other AGN using the same model (NGC 4051, M81*, M87 and Sgr A*), as well as hard- and quiescent-state X-ray binaries. We find that the nuclear broad-band spectrum of M94 is consistent with a relativistic outflow of low inclination. The findings in this work add to the growing body of evidence that the physics of weakly accreting black holes scales with mass in a rather straightforward fashion.

  5. Statistics of a parallel Poynting vector in the auroral zone as a function of altitude using Polar EFI and MFE data and Astrid-2 EMMA data

    Directory of Open Access Journals (Sweden)

    P. Janhunen

    2005-07-01

    Full Text Available We study the wave-related (AC and static (DC parallel Poynting vector (Poynting energy flux as a function of altitude in auroral field lines using Polar EFI and MFE data. The study is statistical and contains 5 years of data in the altitude range 5000–30000 km. We verify the low altitude part of the results by comparison with earlier Astrid-2 EMMA Poynting vector statistics at 1000 km altitude. The EMMA data are also used to statistically compensate the Polar results for the missing zonal electric field component. We compare the Poynting vector with previous statistical DMSP satellite data concerning the electron precipitation power. We find that the AC Poynting vector (Alfvén-wave related Poynting vector is statistically not sufficient to power auroral electron precipitation, although it may, for Kp>2, power 25–50% of it. The statistical AC Poynting vector also has a stepwise transition at R=4 RE, so that its amplitude increases with increasing altitude. We suggest that this corresponds to Alfvén waves being in Landau resonance with electrons, so that wave-induced electron acceleration takes place at this altitude range, which was earlier named the Alfvén Resonosphere (ARS. The DC Poynting vector is ~3 times larger than electron precipitation and corresponds mainly to ionospheric Joule heating. In the morning sector (02:00–06:00 MLT we find that the DC Poynting vector has a nontrivial altitude profile such that it decreases by a factor of ~2 when moving upward from 3 to 4 RE radial distance. In other nightside MLT sectors the altitude profile is more uniform. The morning sector nontrivial altitude profile may be due to divergence of the perpendicular Poynting vector field at R=3–4 RE.

    Keywords. Magnetospheric physics (Auroral phenomena; Magnetosphere-ionosphere interactions – Space plasma physics (Wave-particle interactions

  6. 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.

  7. Radiation dominated relativistic current sheets

    International Nuclear Information System (INIS)

    Jaroschek, C.H.

    2008-01-01

    Relativistic Current Sheets (RCS) feature plasma instabilities considered as potential key to magnetic energy dissipation and non-thermal particle generation in Poynting flux dominated plasma flows. We show in a series of kinetic plasma simulations that the physical nature of non-linear RCS evolution changes in the presence of incoherent radiation losses: In the ultra-relativistic regime (i.e. magnetization parameter sigma = 104 defined as the ratio of magnetic to plasma rest frame energy density) the combination of non-linear RCS dynamics and synchrotron emission introduces a temperature anisotropy triggering the growth of the Relativistic Tearing Mode (RTM). As direct consequence the RTM prevails over the Relativistic Drift Kink (RDK) Mode as competitive RCS instability. This is in contrast to the previously studied situation of weakly relativistic RCS (sigma ∼ 1) where the RDK is dominant and most of the plasma is thermalized. The simulations witness the typical life cycle of ultra-relativistic RCS evolving from a violent radiation induced collapse towards a radiation quiescent state in rather classical Sweet-Parker topology. Such a transition towards Sweet-Parker configuration in the late non-linear evolution has immediate consequences for the efficiency of magnetic energy dissipation and non-thermal particle generation. Ceasing dissipation rates directly affect our present understanding of non-linear RCS evolution in conventional striped wind scenarios. (author)

  8. COUNTER-ROTATION IN RELATIVISTIC MAGNETOHYDRODYNAMIC JETS

    Energy Technology Data Exchange (ETDEWEB)

    Cayatte, V.; Sauty, C. [Laboratoire Univers et Théories, Observatoire de Paris, UMR 8102 du CNRS, Université Paris Diderot, F-92190 Meudon (France); Vlahakis, N.; Tsinganos, K. [Department of Astrophysics, Astronomy and Mechanics, Faculty of Physics, University of Athens, 15784 Zografos, Athens (Greece); Matsakos, T. [Department of Astronomy and Astrophysics, The University of Chicago, Chicago, IL 60637 (United States); Lima, J. J. G., E-mail: veronique.cayatte@obspm.fr [Centro de Astrofísica, Universidade do Porto, Rua das Estrelas, 4150-762 Porto (Portugal)

    2014-06-10

    Young stellar object observations suggest that some jets rotate in the opposite direction with respect to their disk. In a recent study, Sauty et al. showed that this does not contradict the magnetocentrifugal mechanism that is believed to launch such outflows. Motion signatures that are transverse to the jet axis, in two opposite directions, have recently been measured in M87. One possible interpretation of this motion is that of counter-rotating knots. Here, we extend our previous analytical derivation of counter-rotation to relativistic jets, demonstrating that counter-rotation can indeed take place under rather general conditions. We show that both the magnetic field and a non-negligible enthalpy are necessary at the origin of counter-rotating outflows, and that the effect is associated with a transfer of energy flux from the matter to the electromagnetic field. This can be realized in three cases: if a decreasing enthalpy causes an increase of the Poynting flux, if the flow decelerates, or if strong gradients of the magnetic field are present. An illustration of the involved mechanism is given by an example of a relativistic magnetohydrodynamic jet simulation.

  9. Using a tag team of undergraduate researchers to construct an empirical model of auroral Poynting flux, from satellite data

    Science.gov (United States)

    Cosgrove, R. B.; Bahcivan, H.; Klein, A.; Ortega, J.; Alhassan, M.; Xu, Y.; Chen, S.; Van Welie, M.; Rehberger, J.; Musielak, S.; Cahill, N.

    2012-12-01

    Empirical models of the incident Poynting flux and particle kinetic energy flux, associated with auroral processes, have been constructed using data from the FAST satellite. The models were constructed over a three-year period by a tag-team of three groups of undergraduate researchers from Worcester Polytechnic Institute (WPI), working under the supervision of researchers at SRI International, a nonprofit research institute. Each group spent one academic quarter in residence at SRI, in fulfillment of WPI's Major Qualifying Project (MQP), required for graduation from the Department of Electrical and Computer Engineering. The MQP requires a written group report, which was used to transition from one group to the next. The student's research involved accessing and processing a data set of 20,000 satellite orbits, replete with flaws associated with instrument failures, which had to be removed. The data had to be transformed from the satellite reference frame into solar coordinates, projected to a reference altitude, sorted according to geophysical conditions, and etc. The group visits were chaperoned by WPI, and were jointly funded. Researchers at SRI were supported by a grant from the National Science Foundation, which was tailored to accommodate the undergraduate tag-team approach. The NSF grant extended one year beyond the student visits, with increased funding in the final year, permitting the researchers at SRI to exercise quality control, and to produce publications. It is expected that the empirical models will be used as inputs to large-scale general circulation models (GCMs), to specify the atmospheric heating rate at high altitudes.; Poynting Flux with northward IMF ; Poynting flux with southward IMF

  10. Numerical simulation of shear and the Poynting effects by the finite element method: An application of the generalised empirical inequalities in non-linear elasticity

    KAUST Repository

    Angela Mihai, L.

    2013-03-01

    Finite element simulations of different shear deformations in non-linear elasticity are presented. We pay particular attention to the Poynting effects in hyperelastic materials, complementing recent theoretical findings by showing these effects manifested by specific models. As the finite element method computes uniform deformations exactly, for simple shear deformation and pure shear stress, the Poynting effect is represented exactly, while for the generalised shear and simple torsion, where the deformation is non-uniform, the solution is approximated efficiently and guaranteed computational bounds on the magnitude of the Poynting effect are obtained. The numerical results further indicate that, for a given elastic material, the same sign effect occurs under different shearing mechanisms, showing the genericity of the Poynting effect under a variety of shearing loads. In order to derive numerical models that exhibit either the positive or the negative Poynting effect, the so-called generalised empirical inequalities, which are less restrictive than the usual empirical inequalities involving material parameters, are assumed. © 2012 Elsevier Ltd.

  11. High-latitude poynting flux from combined Iridium and SuperDARN data

    Directory of Open Access Journals (Sweden)

    C. L. Waters

    2004-09-01

    Full Text Available Field-aligned currents convey stress between the magnetosphere and ionosphere, and the associated low altitude magnetic and electric fields reflect the flow of electromagnetic energy to the polar ionosphere. We introduce a new technique to measure the global distribution of high latitude Poynting flux, S||, by combining electric field estimates from the Super Dual Auroral Radar Network (SuperDARN with magnetic perturbations derived using magnetometer data from the Iridium satellite constellation. Spherical harmonic methods are used to merge the data sets and calculate S|| for any magnetic local time (MLT from the pole to 60° magnetic latitude (MLAT. The effective spatial resolutions are 2° MLAT, 2h MLT, and the time resolution is about one hour due to the telemetry rate of the Iridium magnetometer data. The technique allows for the assessment of high-latitude net S|| and its spatial distribution on one hour time scales with two key advantages: (1 it yields the net S|| including the contribution of neutral winds; and (2 the results are obtained without recourse to estimates of ionosphere conductivity. We present two examples, 23 November 1999, 14:00-15:00 UT, and 11 March 2000, 16:00-17:00 UT, to test the accuracy of the technique and to illustrate the distributions of S|| that it gives. Comparisons with in-situ S|| estimates from DMSP satellites show agreement to a few mW/m2 and in the locations of S|| enhancements to within the technique's resolution. The total electromagnetic energy flux was 50GW for these events. At auroral latitudes, S|| tends to maximize in the morning and afternoon in regions less than 5° in MLAT by two hours in MLT having S||=10 to 20mW/m2 and total power up to 10GW. The power poleward of the Region 1 currents is about one

  12. High-latitude poynting flux from combined Iridium and SuperDARN data

    Directory of Open Access Journals (Sweden)

    C. L. Waters

    2004-09-01

    Full Text Available Field-aligned currents convey stress between the magnetosphere and ionosphere, and the associated low altitude magnetic and electric fields reflect the flow of electromagnetic energy to the polar ionosphere. We introduce a new technique to measure the global distribution of high latitude Poynting flux, S||, by combining electric field estimates from the Super Dual Auroral Radar Network (SuperDARN with magnetic perturbations derived using magnetometer data from the Iridium satellite constellation. Spherical harmonic methods are used to merge the data sets and calculate S|| for any magnetic local time (MLT from the pole to 60° magnetic latitude (MLAT. The effective spatial resolutions are 2° MLAT, 2h MLT, and the time resolution is about one hour due to the telemetry rate of the Iridium magnetometer data. The technique allows for the assessment of high-latitude net S|| and its spatial distribution on one hour time scales with two key advantages: (1 it yields the net S|| including the contribution of neutral winds; and (2 the results are obtained without recourse to estimates of ionosphere conductivity. We present two examples, 23 November 1999, 14:00-15:00 UT, and 11 March 2000, 16:00-17:00 UT, to test the accuracy of the technique and to illustrate the distributions of S|| that it gives. Comparisons with in-situ S|| estimates from DMSP satellites show agreement to a few mW/m2 and in the locations of S|| enhancements to within the technique's resolution. The total electromagnetic energy flux was 50GW for these events. At auroral latitudes, S|| tends to maximize in the morning and afternoon in regions less than 5° in MLAT by two hours in MLT having S||=10 to 20mW/m2 and total power up to 10GW. The power poleward of the Region 1 currents is about one-third of the total power, indicating significant energy flux over the polar cap.

  13. Statistics of Joule heating in the auroral zone and polar cap using Astrid-2 satellite Poynting flux

    Directory of Open Access Journals (Sweden)

    A. Olsson

    2004-12-01

    Full Text Available We make a statistical study of ionospheric Joule heating with the Poynting flux method using six months of Astrid-2/EMMA electric and magnetic field data during 1999 (solar maximum year. For the background magnetic field we use the IGRF model. Our results are in agreement with earlier statistical satellite studies using both the ΣPE2 method and the Poynting flux method. We present a rather comprehensive set of fitted Joule heating formulas expressing the Joule heating in given magnetic local time (MLT and invariant latitude (ILAT range under given solar illumination conditions as a function of the Kp index, the AE index, the Akasofu epsilon parameter and the solar wind kinetic energy flux. The study thus provides improved and more detailed estimates of the statistical Joule heating. Such estimates are necessary building blocks for future quantitative studies of the power budget in the magnetosphere and in the nightside auroral region. Key words. Ionosphere (electric fields and currents; ionosphere-magnetosphere interactions – Magnetospheric physics (magnetospheric configuration and dynamics

  14. Jet fragmentation

    International Nuclear Information System (INIS)

    Saxon, D.H.

    1985-10-01

    The paper reviews studies on jet fragmentation. The subject is discussed under the topic headings: fragmentation models, charged particle multiplicity, bose-einstein correlations, identified hadrons in jets, heavy quark fragmentation, baryon production, gluon and quark jets compared, the string effect, and two successful models. (U.K.)

  15. Theoretical Developments in QCD Jet Energy Loss

    Energy Technology Data Exchange (ETDEWEB)

    Mehtar-Tani, Yacine

    2016-12-15

    We review the recent developments in the theory of jet-quenching. First, we analyze the coherent vacuum cascade and incoherent medium-induced cascade separately. We then discuss the interplay between the two kinds of cascade and the resulting partial decoherence of the inner jet structure. Finally, we report on recent calculations of higher-order corrections. In particular, the dominant radiative corrections to jet observables that yield the renormalization of the jet-quenching parameter are addressed.

  16. Investigating the anatomy of magnetosheath jets - MMS observations

    Science.gov (United States)

    Karlsson, Tomas; Plaschke, Ferdinand; Hietala, Heli; Archer, Martin; Blanco-Cano, Xóchitl; Kajdič, Primož; Lindqvist, Per-Arne; Marklund, Göran; Gershman, Daniel J.

    2018-04-01

    We use Magnetosphere Multiscale (MMS) mission data to investigate a small number of magnetosheath jets, which are localized and transient increases in dynamic pressure, typically due to a combined increase in plasma velocity and density. For two approximately hour-long intervals in November, 2015 we found six jets, which are of two distinct types. (a) Two of the jets are associated with the magnetic field discontinuities at the boundary between the quasi-parallel and quasi-perpendicular magnetosheath. Straddling the boundary, the leading part of these jets contains an ion population similar to the quasi-parallel magnetosheath, while the trailing part contains ion populations similar to the quasi-perpendicular magnetosheath. Both populations are, however, cooler than the surrounding ion populations. These two jets also have clear increases in plasma density and magnetic field strength, correlated with a velocity increase. (b) Three of the jets are found embedded within the quasi-parallel magnetosheath. They contain ion populations similar to the surrounding quasi-parallel magnetosheath, but with a lower temperature. Out of these three jets, two have a simple structure. For these two jets, the increases in density and magnetic field strength are correlated with the dynamic pressure increases. The other jet has a more complicated structure, and no clear correlations between density, magnetic field strength and dynamic pressure. This jet has likely interacted with the magnetosphere, and contains ions similar to the jets inside the quasi-parallel magnetosheath, but shows signs of adiabatic heating. All jets are associated with emissions of whistler, lower hybrid, and broadband electrostatic waves, as well as approximately 10 s period electromagnetic waves with a compressional component. The latter have a Poynting flux of up to 40 µW m-2 and may be energetically important for the evolution of the jets, depending on the wave excitation mechanism. Only one of the jets is

  17. Investigating the anatomy of magnetosheath jets – MMS observations

    Directory of Open Access Journals (Sweden)

    T. Karlsson

    2018-04-01

    Full Text Available We use Magnetosphere Multiscale (MMS mission data to investigate a small number of magnetosheath jets, which are localized and transient increases in dynamic pressure, typically due to a combined increase in plasma velocity and density. For two approximately hour-long intervals in November, 2015 we found six jets, which are of two distinct types. (a Two of the jets are associated with the magnetic field discontinuities at the boundary between the quasi-parallel and quasi-perpendicular magnetosheath. Straddling the boundary, the leading part of these jets contains an ion population similar to the quasi-parallel magnetosheath, while the trailing part contains ion populations similar to the quasi-perpendicular magnetosheath. Both populations are, however, cooler than the surrounding ion populations. These two jets also have clear increases in plasma density and magnetic field strength, correlated with a velocity increase. (b Three of the jets are found embedded within the quasi-parallel magnetosheath. They contain ion populations similar to the surrounding quasi-parallel magnetosheath, but with a lower temperature. Out of these three jets, two have a simple structure. For these two jets, the increases in density and magnetic field strength are correlated with the dynamic pressure increases. The other jet has a more complicated structure, and no clear correlations between density, magnetic field strength and dynamic pressure. This jet has likely interacted with the magnetosphere, and contains ions similar to the jets inside the quasi-parallel magnetosheath, but shows signs of adiabatic heating. All jets are associated with emissions of whistler, lower hybrid, and broadband electrostatic waves, as well as approximately 10 s period electromagnetic waves with a compressional component. The latter have a Poynting flux of up to 40 µW m−2 and may be energetically important for the evolution of the jets, depending on the wave excitation

  18. Jet Noise Scaling in Dual Stream Nozzles

    Science.gov (United States)

    Khavaran, Abbas; Bridges, James

    2010-01-01

    Power spectral laws in dual stream jets are studied by considering such flows a superposition of appropriate single-stream coaxial jets. Noise generation in each mixing region is modeled using spectral power laws developed earlier for single stream jets as a function of jet temperature and observer angle. Similarity arguments indicate that jet noise in dual stream nozzles may be considered as a composite of four single stream jets representing primary/secondary, secondary/ambient, transition, and fully mixed zones. Frequency filter are designed to highlight spectral contribution from each jet. Predictions are provided at an area ratio of 2.0--bypass ratio from 0.80 to 3.40, and are compared with measurements within a wide range of velocity and temperature ratios. These models suggest that the low frequency noise in unheated jets is dominated by the fully mixed region at all velocity ratios, while the high frequency noise is dominated by the secondary when the velocity ratio is larger than 0.80. Transition and fully mixed jets equally dominate the low frequency noise in heated jets. At velocity ratios less than 0.50, the high frequency noise from primary/bypass becomes a significant contributing factor similar to that in the secondary/ambient jet.

  19. Jet substructure with analytical methods

    Energy Technology Data Exchange (ETDEWEB)

    Dasgupta, Mrinal [University of Manchester, Consortium for Fundamental Physics, School of Physics and Astronomy, Manchester (United Kingdom); Fregoso, Alessandro; Powling, Alexander [University of Manchester, School of Physics and Astronomy, Manchester (United Kingdom); Marzani, Simone [Durham University, Institute for Particle Physics Phenomenology, Durham (United Kingdom)

    2013-11-15

    We consider the mass distribution of QCD jets after the application of jet-substructure methods, specifically the mass-drop tagger, pruning, trimming and their variants. In contrast to most current studies employing Monte Carlo methods, we carry out analytical calculations at the next-to-leading order level, which are sufficient to extract the dominant logarithmic behaviour for each technique, and compare our findings to exact fixed-order results. Our results should ultimately lead to a better understanding of these jet-substructure methods which in turn will influence the development of future substructure tools for LHC phenomenology. (orig.)

  20. On the universality of quark jet fragmentation

    International Nuclear Information System (INIS)

    Dias de Deus, J.; Jadach, S.

    1977-01-01

    Universality of inclusive fragmentation density functions in lepton induced processes (ep, γp, e + e - ) and purely hadronic processes is discussed from the point of view of the Topological Expansion/Dual Unitarization Scheme. It is shown that planar, single jet dominated processes have universal inclusive distributions and average multiplicities. In multi-jet processes, treated in a simple approximation, is inversely proportional to the number N of jets and the magnitude of the seagull effect increases as N 2 . (Auth.)

  1. Boosted jets

    International Nuclear Information System (INIS)

    Juknevich, J.

    2014-01-01

    We present a study of the substructure of jets high transverse momentum at hadron colliders. A template method is introduced to distinguish heavy jets by comparing their energy distributions to the distributions of a set of templates which describe the kinematical information from signal or background. As an application, a search for a boosted Higgs boson decaying into bottom quarks in association with a leptonically decaying W boson is presented as well. (author)

  2. The kinetically dominated quasar 3C 418

    Science.gov (United States)

    Punsly, Brian; Kharb, Preeti

    2017-06-01

    The existence of quasars that are kinetically dominated, where the jet kinetic luminosity, Q, is larger than the total (infrared to X-ray) thermal luminosity of the accretion flow, Lbol, provides a strong constraint on the fundamental physics of relativistic jet formation. Since quasars have high values of Lbol by definition, only ˜10 kinetically dominated quasars (with \\overline{Q}/L_{bol}>1) have been found, where \\overline{Q} is the long-term time-averaged jet power. We use low-frequency (151 MHz-1.66 GHz) observations of the quasar 3C 418 to determine \\overline{Q}≈ 5.5 ± 1.3 × 10^{46} {erg s^{-1}}. Analysis of the rest-frame ultraviolet spectrum indicates that this equates to 0.57 ± 0.28 times the Eddington luminosity of the central supermassive black hole and \\overline{Q}/L_{bol} ≈ 4.8 ± 3.1, making 3C 418 one of the most kinetically dominated quasars found to date. It is shown that this maximal \\overline{Q}/L_{bol} is consistent with models of magnetically arrested accretion of jet production in which the jet production reproduces the observed trend of a decrement in the extreme ultraviolet continuum as the jet power increases. This maximal condition corresponds to an almost complete saturation of the inner accretion flow with vertical large-scale magnetic flux (maximum saturation).

  3. NASA Jet Noise Research

    Science.gov (United States)

    Henderson, Brenda

    2016-01-01

    The presentation highlights NASA's jet noise research for 2016. Jet-noise modeling efforts, jet-surface interactions results, acoustic characteristics of multi-stream jets, and N+2 Supersonic Aircraft system studies are presented.

  4. Domination versus disjunctive domination in graphs | Henning ...

    African Journals Online (AJOL)

    Domination versus disjunctive domination in graphs. Michael A Henning, Sinclair A Marcon. Abstract. A dominating set in a graph G is a set S of vertices of G such that every vertex not in S is adjacent to a vertex of S. The domination number of G is the minimum cardinality of a dominating set of G. For a positive integer b, ...

  5. Unsteady jet-slug dynamics

    International Nuclear Information System (INIS)

    Kang, S.W.

    1977-01-01

    The present analysis treats the transient load characteristics at the wet-well bottom during the vent-clearing event under loss-of-coolant accident conditions. A conceptual model is introduced wherein the liquid-jet inertia and the net momentum-efflux are the two dominant physical factors. The derived load-history equations were found to be functions of the vent-clearing characteristics and of the jet-decay mode in the liquid pool. The theoretical results obtained by a physical modelling of these phenomena appear to agree reasonably well with the available data from UCLA and from LLL 1 / 5 -scale experiments

  6. Domination, Eternal Domination, and Clique Covering

    Directory of Open Access Journals (Sweden)

    Klostermeyer William F.

    2015-05-01

    Full Text Available Eternal and m-eternal domination are concerned with using mobile guards to protect a graph against infinite sequences of attacks at vertices. Eternal domination allows one guard to move per attack, whereas more than one guard may move per attack in the m-eternal domination model. Inequality chains consisting of the domination, eternal domination, m-eternal domination, independence, and clique covering numbers of graph are explored in this paper.

  7. 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...

  8. Jet Crackle

    Science.gov (United States)

    2015-06-23

    crackle is correlated to signals with intermittent periods of steepened shock-like waves followed by weaker, longer, rounded rarefaction regions, but to...turbulence is concentrated in a weakly curved (for a typical round jet) shear layer between the high-speed potential core flow and the surrounding co-flow...decreases into the acoustic field. The effect of varying dc between −0.1 and −0.003δm(t)/∆U causes the Nδm/Lx curves to shift downward as fewer waves

  9. Sex-linked dominant

    Science.gov (United States)

    Inheritance - sex-linked dominant; Genetics - sex-linked dominant; X-linked dominant; Y-linked dominant ... can be either an autosomal chromosome or a sex chromosome. It also depends on whether the trait ...

  10. Jet production in photon-photon interactions

    International Nuclear Information System (INIS)

    Berger, C.; Genzel, H.; Lackas, W.; Pielorz, J.; Raupach, F.; Wagner, W.; Buerger, J.; Criegee, L.; Deuter, A.; Franke, G.; Gerke, C.; Knies, G.; Lewendel, B.; Meyer, J.; Michelsen, U.; Pape, K.H.; Timm, U.; Winter, G.G.; Zimmermann, W.; Zachara, M.; Ferrarotto, F.; Gaspero, M.; Stella, B.; Bussey, P.J.; Cartwright, S.L.; Dainton, J.B.; Hendry, D.; King, B.T.; Raine, C.; Scarr, J.M.; Skillicorn, I.O.; Smith, K.M.; Thomson, J.C.; Achterberg, O.; Blobel, V.; Burkart, D.; Diehlmann, K.; Feindt, M.; Kapitza, H.; Koppitz, B.; Krueger, M.; Poppe, M.; Spitzer, H.; Staa, R. van; Almeida, F.; Baecker, A.; Barreiro, F.; Brandt, S.; Derikum, K.; Grupen, C.; Meyer, H.J.; Mueller, H.; Neumann, B.; Rost, M.; Stupperich, K.; Zech, G.; Alexander, G.; Bella, G.; Gnat, Y.; Grunhaus, J.; Junge, H.; Kraski, K.; Maxeiner, C.; Maxeiner, H.; Meyer, H.; Schmidt, D.

    1987-01-01

    We present results on jet production in γγ interactions where both photons are quasi-real. The invariant masses of the hadronic system are limited to the range 4≤W vis 12 GeV/c 2 . The data approach the Quark-Parton-Model (QPM) expectation at the highest p T jet values (≥4 GeV/c). Jet production at low p T (≤1 GeV/c) can be described by a Vector Dominance derived model. The data also have a component with no apparent jet structure in the range, 1.0≤p T jet ≤4.0 GeV/c which can be described by phase space or by models of the QCD hard scattering processes γγ→qanti qg and γγ→qanti qqanti q. (orig.)

  11. Jet energy resolution of the SDC detector

    International Nuclear Information System (INIS)

    Para, A.; Beretvas, A.; Denisenko, K.; Denisenko, N.; Green, D.; Yeh, G.P.; Wu, W.; Iso, H.

    1990-01-01

    We have answered the PAC question (''Demonstrate the jet energy resolution of your proposed detector by studying decays Z → jet + jet and Z' → jet + jet, M Z' = 1 TeV.'') using a general program called SSCSIM. This program is a tool for investigating simple questions involving the relations between detector parameters and physics capabilities of a detector. A different package called ANLSIM developed by our colleagues at Argonne has also been used to answer this question. The results as expected are very similar. In this note we will try to document our procedures. Our tentative conclusion from this study is that physics induced effects, out-of-cone fluctuations and underlying event fluctuations, dominate the resolution. Pushing the detector performance to the limits of technology improves the effective resolution by at most 20%. 20 refs., 6 figs., 5 tabs

  12. Supersonic induction plasma jet modeling

    International Nuclear Information System (INIS)

    Selezneva, S.E.; Boulos, M.I.

    2001-01-01

    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

  13. Jet inclusive cross sections

    International Nuclear Information System (INIS)

    Del Duca, V.

    1992-11-01

    Minijet production in jet inclusive cross sections at hadron colliders, with large rapidity intervals between the tagged jets, is evaluated by using the BFKL pomeron. We describe the jet inclusive cross section for an arbitrary number of tagged jets, and show that it behaves like a system of coupled pomerons

  14. Jet Joint Undertaking

    International Nuclear Information System (INIS)

    Keen, B.E.; O'Hara, G.W.; Pollard, I.E.

    1988-07-01

    The paper presents the Jet Joint Undertaking annual report 1987. A description is given of the JET and Euratom and International Fusion Programmes. The technical status of JET is outlined, including the development and improvements made to the system in 1987. The results of JET Operation in 1987 are described within the areas of: density effects, temperature improvements, energy confinement studies and other material effects. The contents also contain a summary of the future programme of JET. (U.K.)

  15. Power deposition profiles and Poynting vector distribution of phased antenna arrays in the ion-cyclotron resonance heating of a NET/INTOR-type tokamak

    International Nuclear Information System (INIS)

    Bhatnagar, V.P.; Koch, R.

    1986-01-01

    The heating produced by magnetosonic waves launched from phased antenna arrays in the ion-cyclotron range of frequencies is studied for a large tokamak with NET/INTOR-like parameters. The model used combines a 3-D planar, cold-plasma, antenna-plasma coupling code and a 3-D non-circular, toroidal, hot-plasma/ray-tracing code. First, the fractional power absorption of a ray during a single transit through the absorption layer is studied in a D-T plasma indicating total absorption in all INTOR cases except during the initial state characterized by low plasma temperature and density. However, in this case the single-pass wave absorption can be increased considerably by adding a few per cent of hydrogen. Further, complete power deposition profiles and Poynting vector distributions are presented for 'symmetric' and 'antisymmetric' 2x2 antenna array configurations with ksub(parallel)-shaping. Excitation of coaxial modes has, for the first time, been demonstrated explicitly by analysis of the Poynting vector distribution in real space. An antenna configuration with a π-phasing in the z-direction (such that the radiated power spectrum peaks at ksub(parallel) approx.= 5 m -1 ) and the choice of 3lambda/4 long antenna elements with 'symmetric' excitation in the y-direction, are found to produce central RF power deposition profiles in the second-harmonic and minority heating of INTOR. Finally, from a comparison of results for circular and non-circular NET/INTOR plasmas with elongation kappa=1.6, it is found that in the latter wave focusing is greatly reduced and that the power density figures are lower by approximately a factor of 1.9 for the case treated. (author)

  16. Vector boson tagged jets and jet substructure

    Directory of Open Access Journals (Sweden)

    Vitev Ivan

    2018-01-01

    Full Text Available In these proceedings, we report on recent results related to vector boson-tagged jet production in heavy ion collisions and the related modification of jet substructure, such as jet shapes and jet momentum sharing distributions. Z0-tagging and γ-tagging of jets provides new opportunities to study parton shower formation and propagation in the quark-gluon plasma and has been argued to provide tight constrains on the energy loss of reconstructed jets. We present theoretical predictions for isolated photon-tagged and electroweak boson-tagged jet production in Pb+Pb collisions at √sNN = 5.02 TeV at the LHC, addressing the modification of their transverse momentum and transverse momentum imbalance distributions. Comparison to recent ATLAS and CMS experimental measurements is performed that can shed light on the medium-induced radiative corrections and energy dissipation due to collisional processes of predominantly quark-initiated jets. The modification of parton splitting functions in the QGP further implies that the substructure of jets in heavy ion collisions may differ significantly from the corresponding substructure in proton-proton collisions. Two such observables and the implication of tagging on their evaluation is also discussed.

  17. Understanding jet noise.

    Science.gov (United States)

    Karabasov, S A

    2010-08-13

    Jets are one of the most fascinating topics in fluid mechanics. For aeronautics, turbulent jet-noise modelling is particularly challenging, not only because of the poor understanding of high Reynolds number turbulence, but also because of the extremely low acoustic efficiency of high-speed jets. Turbulent jet-noise models starting from the classical Lighthill acoustic analogy to state-of-the art models were considered. No attempt was made to present any complete overview of jet-noise theories. Instead, the aim was to emphasize the importance of sound generation and mean-flow propagation effects, as well as their interference, for the understanding and prediction of jet noise.

  18. Very forward jet, Mueller Navelet jets and jet gap jet measurements in CMS

    CERN Document Server

    Cerci, Salim

    2018-01-01

    The measurements of very forward jet, Mueller-Navelet jets and jet-gap-jet events are presented for different collision energies. The analyses are based on data collected with the CMS detector at the LHC. Jets are defined through the anti-$k_\\mathrm{t}$ clustering algorithm for different cone sizes. Jet production studies provide stringent tests of quantum chromodynamics (QCD) and contribute to tune Monte Carlo (MC) simulations and phenomenological models. The measurements are compared to predictions from various Monte Carlo event generators.

  19. Multi-jet correlations and colour coherence phenomena

    Directory of Open Access Journals (Sweden)

    Lee Jason S.H.

    2017-01-01

    Full Text Available In multi-jet events, colour coherence was shown to play a important role in the topology of these events. In modern Monte Carlo generators, the colour coherence effect has become an inherent feature, such that the colour coherence effect can no longer be disentangled in a simple manner. This study looks at the multi-jet correlations by comparing Monte Carlo generators in Parton Shower dominant and Matrix Element dominant regions.

  20. Nonlinear stability of supersonic jets

    Science.gov (United States)

    Tiwari, S. N. (Principal Investigator); Bhat, T. R. S. (Principal Investigator)

    1996-01-01

    The stability calculations made for a shock-free supersonic jet using the model based on parabolized stability equations are presented. In this analysis the large scale structures, which play a dominant role in the mixing as well as the noise radiated, are modeled as instability waves. This model takes into consideration non-parallel flow effects and also nonlinear interaction of the instability waves. The stability calculations have been performed for different frequencies and mode numbers over a range of jet operating temperatures. Comparisons are made, where appropriate, with the solutions to Rayleigh's equation (linear, inviscid analysis with the assumption of parallel flow). The comparison of the solutions obtained using the two approaches show very good agreement.

  1. PERFORMANCE OF THE ATLAS JET TRIGGER AND FUTURE DEVELOPMENTS

    CERN Document Server

    Sherafati, Nima; The ATLAS collaboration

    2017-01-01

    The ATLAS experiment at the LHC uses a two-level trigger system to record interesting events maintaining good signal efficiency at lower energies where pileup dominates. A new challenge is to control the increased trigger rate due to the expected higher pileup for LHC Run 2. This poster presents the jet trigger efficiency as a function of the offline jet transverse momentum for proton-proton collision data at the centre-of-mass energy of 13 TeV. In addition, the efficiencies of global sequential calibrated (GSC) jet trigger, trimmed jet and trimmed dijet triggers are shown.

  2. Jet Vertex Charge Reconstruction

    CERN Document Server

    Nektarijevic, Snezana; The ATLAS collaboration

    2015-01-01

    A newly developed algorithm called the jet vertex charge tagger, aimed at identifying the sign of the charge of jets containing $b$-hadrons, referred to as $b$-jets, is presented. In addition to the well established track-based jet charge determination, this algorithm introduces the so-called \\emph{jet vertex charge} reconstruction, which exploits the charge information associated to the displaced vertices within the jet. Furthermore, the charge of a soft muon contained in the jet is taken into account when available. All available information is combined into a multivariate discriminator. The algorithm has been developed on jets matched to generator level $b$-hadrons provided by $t\\bar{t}$ events simulated at $\\sqrt{s}$=13~TeV using the full ATLAS detector simulation and reconstruction.

  3. Delving into QCD jets

    International Nuclear Information System (INIS)

    Konishi, K.

    1980-01-01

    The author discusses, in an introductory fashion, the latest developments in the study of hadronic jets produced in hard processes, based on perturbative QCD. Emphasis is on jet calculus (and its applications and generalizations), and on the appearance of a parton-like consistent, over-all picture of jet evolution in momentum, colour, and real space-time. (Auth.)

  4. Topics on domination

    CERN Document Server

    Hedetniemi, ST

    1991-01-01

    The contributions in this volume are divided into three sections: theoretical, new models and algorithmic. The first section focuses on properties of the standard domination number &ggr;(G), the second section is concerned with new variations on the domination theme, and the third is primarily concerned with finding classes of graphs for which the domination number (and several other domination-related parameters) can be computed in polynomial time.

  5. Sting jets in intense winter North-Atlantic windstorms

    International Nuclear Information System (INIS)

    Martínez-Alvarado, Oscar; Gray, Suzanne L; Clark, Peter A; Catto, Jennifer L

    2012-01-01

    Extratropical cyclones dominate autumn and winter weather over western Europe. The strongest cyclones, often termed windstorms, have a large socio-economic impact due to the strong surface winds and associated storm surges in coastal areas. Here we show that sting jets are a common feature of windstorms; up to a third of the 100 most intense North-Atlantic winter windstorms over the last two decades satisfy conditions for sting jets. The sting jet is a mesoscale descending airstream that can cause strong near-surface winds in the dry slot of the cyclone, a region not usually associated with strong winds. Despite their localized transient nature, these sting jets can cause significant damage, a prominent example being the storm that devastated southeast England on 16 October 1987. We present the first regional climatology of windstorms with sting jets. Previously analysed sting-jet cases appear to have been exceptional in their track over northwest Europe rather than in their strength. (letter)

  6. Dominance in domestic dogs

    NARCIS (Netherlands)

    Borg, Van Der J.A.M.; Schilder, M.B.H.; Vinke, C.M.; Vries, De Han; Petit, Odile

    2015-01-01

    A dominance hierarchy is an important feature of the social organisation of group living animals. Although formal and/or agonistic dominance has been found in captive wolves and free-ranging dogs, applicability of the dominance concept in domestic dogs is highly debated, and quantitative data are

  7. Total well dominated trees

    DEFF Research Database (Denmark)

    Finbow, Arthur; Frendrup, Allan; Vestergaard, Preben D.

    cardinality then G is a total well dominated graph. In this paper we study composition and decomposition of total well dominated trees. By a reversible process we prove that any total well dominated tree can both be reduced to and constructed from a family of three small trees....

  8. A new look for the Southern Hemisphere jet stream

    Energy Technology Data Exchange (ETDEWEB)

    Gallego, D.; Ribera, P. [Facultad de CC Ambientales, Universidad Pablo de Olavide, Seville (Spain); Garcia-Herrera, R.; Hernandez, E. [Facultad de CC Fisicas, Universidad Complutense de Madrid (Spain); Gimeno, L. [Facultad de Ciencias, Universidad de Vigo, Orense (Spain)

    2005-05-01

    A new jet stream description, defined as the geostrophic streamline of maximum average velocity is proposed. An objective algorithm for detecting and tracking the jet has been developed, tested and applied to the NCEP/NCAR 200-hPa geopotential height in the Southern Hemisphere for the period 1958-2002. The results show the variability of the double character of the Southern Hemisphere jet, with a marked seasonality. During the warm season, a single jet can be found around 40 S, while autumn and winter are characterized by a clear double jet structure, with a strong and dominant subtropical jet located around 30 S and a polar front jet, progressively displaced toward southern latitudes and reaching 60 S by the end of the cold season. In general, a trend toward slower subtropical jets and stronger polar front jets has been detected during the study period. The Southern Annular Mode appears as a main modulator of the latitude and strength of the polar front jet, influencing to a minor extent its subtropical counterpart. The ENSO cycle strongly modifies the latitude and specially the strength of the subtropical jet, affecting its preferred wavenumber as well. Nevertheless, the effect of this oscillation seems fairly restricted in the Pacific, thus limiting the ability of this jet to drive the El Nino teleconnections along the Southern Hemisphere. The consistency of the results, when compared with previous jet climatologies, suggests that the new approach is a reliable jet-tracking method, thus providing a new tool to analyze climatic variability at hemispheric scales.

  9. JET Joint Undertaking

    International Nuclear Information System (INIS)

    Keen, B.E.; Lallia, P.; O'Hara, G.W.; Pollard, I.E.

    1987-06-01

    The paper presents the annual report of the Joint European Torus (JET) Joint Undertaking, 1986. The report is divided into two parts: a part on the scientific and technical programme of the project, and a part setting out the administration and organisation of the Project. The first part includes: a summary of the main features of the JET apparatus, the JET experimental programme, the position of the Project in the overall Euratom programme, and how JET relates to other large fusion devices throughout the world. In addition, the technical status of JET is described, as well as the results of the JET operations in 1986. The final section of the first part outlines the proposed future programme of JET. (U.K.)

  10. 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.

  11. Operation DOMINIC I-1962.

    Science.gov (United States)

    1983-02-01

    OOMINIC. Quantity Item 4 Sellers Injector Corp. Liquid Jet Cleaners with Lance and Discharge Hose 2 Gelman Air Sampler with Dry Test Meter 2 289 Tritium...Veterans Administration - RO Fort Harrison, MT San Juan , Puerto Rico ATTN: Director ATTN: Director p. Veterans Administration - RO Veterans Administration

  12. Z boson production in association with heavy quark jets at D0

    Energy Technology Data Exchange (ETDEWEB)

    Zennamo, III, Joseph Anthony [State Univ. of New York (SUNY), Buffalo, NY (United States)

    2013-10-28

    The dominant background in searches for a Higgs boson decaying into b-quarks at the Tevatron is production of a Z boson in association with either b- or c-quark initiated jets (b or c jets). This thesis describes the first measurements of the ratio of differential cross sections σ (Z + b jet)/ σ(Z + jet), and the first measurements of the ratio of cross sections σ (Z + c jet)/ σ(Z + jet) and σ (Z + c jet)/ σ(Z + b jet). These measurements are performed using the full D0 Run II data set corresponding to an integrated luminosity of 9.7 fb-1. The ratio of differential cross sections σ(Z + b jet)/σ (Z + jet) have been measured as a function of jet and Z boson pT , jet η , and Δφ(Z, jet). The Z+c jet ratios of differential cross sections are measured as a function of jet and Z boson pT .

  13. Experimental study of elliptical jet from sub to supercritical conditions

    Energy Technology Data Exchange (ETDEWEB)

    Muthukumaran, C. K.; Vaidyanathan, Aravind, E-mail: aravind7@iist.ac.in [Department of Aerospace Engineering, Indian Institute of Space Science and Technology, Trivandrum, Kerala 695547 (India)

    2014-04-15

    The jet mixing at supercritical conditions involves fluid dynamics as well as thermodynamic phenomena. All the jet mixing studies at critical conditions to the present date have focused only on axisymmetric jets. When the liquid jet is injected into supercritical environment, the thermodynamic transition could be well understood by considering one of the important fluid properties such as surface tension since it decides the existence of distinct boundary between the liquid and gaseous phase. It is well known that an elliptical liquid jet undergoes axis-switching phenomena under atmospheric conditions due to the presence of surface tension. The experimental investigations were carried out with low speed elliptical jet under supercritical condition. Investigation of the binary component system with fluoroketone jet and N{sub 2} gas as environment shows that the surface tension force dominates for a large downstream distance, indicating delayed thermodynamic transition. The increase in pressure to critical state at supercritical temperature is found to expedite the thermodynamic transition. The ligament like structures has been observed rather than droplets for supercritical pressures. However, for the single component system with fluoroketone jet and fluoroketone environment shows that the jet disintegrates into droplets as it is subjected to the chamber conditions even for the subcritical pressures and no axis switching phenomenon is observed. For a single component system, as the pressure is increased to critical state, the liquid jet exhibits gas-gas like mixing behavior and that too without exhibiting axis-switching behavior.

  14. The social dominance paradox.

    Science.gov (United States)

    Cook, Jennifer Louise; den Ouden, Hanneke E M; Heyes, Cecilia M; Cools, Roshan

    2014-12-01

    Dominant individuals report high levels of self-sufficiency, self-esteem, and authoritarianism. The lay stereotype suggests that such individuals ignore information from others, preferring to make their own choices. However, the nonhuman animal literature presents a conflicting view, suggesting that dominant individuals are avid social learners, whereas subordinates focus on learning from private experience. Whether dominant humans are best characterized by the lay stereotype or the animal view is currently unknown. Here, we present a "social dominance paradox": using self-report scales and computerized tasks, we demonstrate that socially dominant people explicitly value independence, but, paradoxically, in a complex decision-making task, they show an enhanced reliance (relative to subordinate individuals) on social learning. More specifically, socially dominant people employed a strategy of copying other agents when the agents' responses had a history of being correct. However, in humans, two subtypes of dominance have been identified: aggressive and social. Aggressively dominant individuals, who are as likely to "get their own way" as socially dominant individuals but who do so through the use of aggressive or Machiavellian tactics, did not use social information, even when it was beneficial to do so. This paper presents the first study of dominance and social learning in humans and challenges the lay stereotype in which all dominant individuals ignore others' views. The more subtle perspective we offer could have important implications for decision making in both the boardroom and the classroom. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Comparison between dominant NB and dominant IC heated ELMy H-mode discharges in JET

    NARCIS (Netherlands)

    Versloot, T.W.; Sartori, R.; de Vries, P.C.; et al, [No Value

    2011-01-01

    Abstract The experiment described in this paper is aimed at characterization of ELMy H-mode discharges with varying momentum input, rotation, power deposition profiles and ion to electron heating ratio obtained by varying the proportion between ion cyclotron (IC) and neutral beam (NB) heating. The

  16. Comparison between dominant NB and dominant IC heated ELMy H-mode discharges in JET

    NARCIS (Netherlands)

    Versloot, T. W.; Sartori, R.; Rimini, F.; de Vries, P. C.; Saibene, G.; Parail, V.; Beurskens, M. N. A.; Boboc, A.; Budny, R.; Crombe, K.; de la Luna, E.; Durodie, F.; Eich, T.; Giroud, C.; Kiptily, V.; Johnson, T.; Mantica, P.; Mayoral, M. L.; McDonald, D. C.; Monakhov, I.; Nave, M. F. F.; Voitsekhovitch, I.; Zastrow, K. D.

    2011-01-01

    The experiment described in this paper is aimed at characterization of ELMy H-mode discharges with varying momentum input, rotation, power deposition profiles and ion to electron heating ratio obtained by varying the proportion between ion cyclotron (IC) and neutral beam (NB) heating. The motivation

  17. Relating 2-Rainbow Domination To Roman Domination

    Directory of Open Access Journals (Sweden)

    Alvarado José D.

    2017-11-01

    Full Text Available For a graph G, let R(G and yr2(G denote the Roman domination number of G and the 2-rainbow domination number of G, respectively. It is known that yr2(G ≤ R(G ≤ 3/2yr2(G. Fujita and Furuya [Difference between 2-rainbow domination and Roman domination in graphs, Discrete Appl. Math. 161 (2013 806-812] present some kind of characterization of the graphs G for which R(G − yr2(G = k for some integer k. Unfortunately, their result does not lead to an algorithm that allows to recognize these graphs efficiently. We show that for every fixed non-negative integer k, the recognition of the connected K4-free graphs G with yR(G − yr2(G = k is NP-hard, which implies that there is most likely no good characterization of these graphs. We characterize the graphs G such that yr2(H = yR(H for every induced subgraph H of G, and collect several properties of the graphs G with R(G = 3/2yr2(G.

  18. 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

  19. A systematic study of supersonic jet noise.

    Science.gov (United States)

    Louis, J. F.; Letty, R. P.; Patel, J. R.

    1972-01-01

    The acoustic fields for a rectangular and for an axisymmetric nozzle configuration are studied. Both nozzles are designed for identical flow parameters. It is tried to identify the dominant noise mechanisms. The other objective of the study is to establish scaling laws of supersonic jet noise. A shock tunnel is used in the investigations. Measured sound directivity, propagation direction of Mach waves obtained by shadowgraphs, and the slight dependence of the acoustic efficiency on the level of expansion indicate that Mach waves contribute significantly to the noise produced by a rectangular jet.

  20. On jet substructure methods for signal jets

    Energy Technology Data Exchange (ETDEWEB)

    Dasgupta, Mrinal [Consortium for Fundamental Physics, School of Physics & Astronomy, University of Manchester,Oxford Road, Manchester M13 9PL (United Kingdom); Powling, Alexander [School of Physics & Astronomy, University of Manchester,Oxford Road, Manchester M13 9PL (United Kingdom); Siodmok, Andrzej [Institute of Nuclear Physics, Polish Academy of Sciences,ul. Radzikowskiego 152, 31-342 Kraków (Poland); CERN, PH-TH,CH-1211 Geneva 23 (Switzerland)

    2015-08-17

    We carry out simple analytical calculations and Monte Carlo studies to better understand the impact of QCD radiation on some well-known jet substructure methods for jets arising from the decay of boosted Higgs bosons. Understanding differences between taggers for these signal jets assumes particular significance in situations where they perform similarly on QCD background jets. As an explicit example of this we compare the Y-splitter method to the more recently proposed Y-pruning technique. We demonstrate how the insight we gain can be used to significantly improve the performance of Y-splitter by combining it with trimming and show that this combination outperforms the other taggers studied here, at high p{sub T}. We also make analytical estimates for optimal parameter values, for a range of methods and compare to results from Monte Carlo studies.

  1. 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.

  2. Jet quenching at ALICE

    International Nuclear Information System (INIS)

    Bianchi, Nicola

    2007-01-01

    RHIC results on leading hadron suppression indicate that the jets produced in hard processes are strongly quenched by the dense medium created in heavy ion collisions. Most of the energy lost by the leading parton remains within the jet cone, but several questions on the medium modification of the jet structure have not been addressed. These include the longitudinal and transverse structures of the quenched jet, the associated radiation observables, and the dependence on the parton flavor. These topics will be studied by ALICE thanks to both the robustness of its tracking and the charged particle identification system. Large medium effects are expected in both the low pt and in the high pt regions. To make ALICE better suited for jet physics, the performances on high p t particles and jets can be significantly improved by completing the present set-up with a large Electromagnetic Calorimeter (EmCal). This will significantly improve the resolution on the jet energy and on the particle composition (with the detection of both charged and neutral particles). It will also allow to calibrate the jet energy by measuring the high energy photon emitted in the opposite direction. EmCal will be used to trigger on the jet energy itself, thus allowing a significant improvement of the statistics achievable for jets of high energy. Finally, due too both the γ/π 0 and the electron/hadron discrimination, EmCal will enhance the ALICE capabilities at high p t for direct photons and heavy quarks measurements

  3. Jets in Planetary Atmospheres

    Science.gov (United States)

    Dowling, Tim

    2018-05-01

    Jet streams, "jets" for short, are remarkably coherent streams of air found in every major atmosphere. They have a profound effect on a planet's global circulation, and have been an enigma since the belts and zones of Jupiter were discovered in the 1600s. The study of jets, including what processes affect their size, strength, direction, shear stability, and predictability, are active areas of research in geophysical fluid dynamics. Jet research is multidisciplinary and global, involving collaborations between observers, experimentalists, numerical modelers, and applied mathematicians. Jets in atmospheres have strong analogies with shear instability in nonneutral plasmas, and these connections are highlighted throughout the article. The article begins with a description of four major challenges that jet researchers face: nonlinearity, non-intuitive wave physics, non-constant-coefficients, and copious nondimensional numbers. Then, two general fluid-dynamical tenets, the practice of rendering expressions dimensionally homogeneous (nondimensional), and the universal properties of shocks are applied to the open question of what controls the on-off switch of shear instability. The discussion progresses to how the physics of jets varies in equatorial, midlatitude, and polar regions, and how jets are observed to behave in each of these settings. The all-in-one conservation law of potential vorticity (PV), which combines the conservation laws of mass, momentum, and thermal energy into a single expression, is the common language of jet research. Earth and Uranus have weak retrograde equatorial jets, but most planets exhibit super-rotating equatorial jets, which require eddies to transport momentum up gradient in a non-intuitive manner. Jupiter and Saturn exhibit multiple alternating jets in their midlatitudes. The theory for why jets are invariably zonal (east-west orientated) is reviewed, and the particular challenges that Jupiter's sharp westward jets present to existing

  4. VVER-1000 dominance ratio

    International Nuclear Information System (INIS)

    Gorodkov, S.

    2009-01-01

    Dominance ratio, or more precisely, its closeness to unity, is important characteristic of large reactor. It allows evaluate beforehand the number of source iterations required in deterministic calculations of power spatial distribution. Or the minimal number of histories to be modeled for achievement of statistical error level desired in large core Monte Carlo calculations. In this work relatively simple approach for dominance ratio evaluation is proposed. It essentially uses core symmetry. Dependence of dominance ratio on neutron flux spatial distribution is demonstrated. (author)

  5. WWER-1000 dominance ratio

    International Nuclear Information System (INIS)

    Gorodkov, S.S.

    2009-01-01

    Dominance ratio, or more precisely, its closeness to unity, is important characteristic of large reactor. It allows evaluate beforehand the number of source iterations required in deterministic calculations of power spatial distribution. Or the minimal number of histories to be modeled for achievement of statistical error level desired in large core Monte Carlo calculations. In this work relatively simple approach for dominance ratio evaluation is proposed. It essentially uses core symmetry. Dependence of dominance ratio on neutron flux spatial distribution is demonstrated. (Authors)

  6. Elitism and Stochastic Dominance

    OpenAIRE

    Bazen, Stephen; Moyes, Patrick

    2011-01-01

    Stochastic dominance has typically been used with a special emphasis on risk and inequality reduction something captured by the concavity of the utility function in the expected utility model. We claim that the applicability of the stochastic dominance approach goes far beyond risk and inequality measurement provided suitable adpations be made. We apply in the paper the stochastic dominance approach to the measurment of elitism which may be considered the opposite of egalitarianism. While the...

  7. Phenomenology of jets

    International Nuclear Information System (INIS)

    Walsh, T.F.

    1980-05-01

    The basic idea of these lectures is very simple. Quarks and gluons - the elementary quanta of quantum chromodynamics or QCD - are produced with perturbarively calculable rates in short distance processes. This is because of asymptotic freedom. These quanta produced at short distances are, in a sense, 'visible' as jets of hadrons. (The jets do not contain the colored QCD quanta if - as we will assume - color is confined. The jets contain only colorless hadrons.) The distribution of these jets is the distribution of the original quanta, apart from fluctuations generated in the (long distance) jet formation process. The distribution of the jets can thus thest QCD in a particularly clear way at the parton level, at distance of order 5 x 10 -16 cm (PETRA/PEP energies). (orig.)

  8. Hadronic jets an introduction

    CERN Document Server

    Banfi, Andrea

    2016-01-01

    Jet physics is an incredibly rich subject detailing the narrow cone of hadrons and other particles produced by the hadronization of a quark or gluon in a particle physics or heavy ion experiment. This book is a general overview of jet physics for scientists not directly involved in the field. It presents the basic experimental and theoretical problems arising when dealing with jets, and describing the solutions proposed in recent years.

  9. JET Joint Undertaking

    International Nuclear Information System (INIS)

    Keen, B.E.

    1988-03-01

    The paper is a JET progress report 1987, and covers the fourth full year of JET's operation. The report contains an overview summary of the scientific and technical advances during the year, and is supplemented by appendices of detailed contributions of the more important JET articles published during 1987. The document is aimed at specialists and experts engaged in nuclear fusion and plasma physics, as well as the general scientific community. (U.K.)

  10. 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)

  11. Properties of gluon jets

    International Nuclear Information System (INIS)

    Sugano, K.

    1987-01-01

    The properties of gluon jets are reviewed, and the measured characteristics are compared to the theoretical expectations. Although neither data nor models for the gluon jets are in the mature stage, in general the agreement between experiment and theory is remarkable. There are some intriguing differences. Since 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

  12. Properties of gluon jets

    International Nuclear Information System (INIS)

    Sugano, K.

    1988-01-01

    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 understanding of QCD. The future prospects are discussed

  13. Are jets really there

    International Nuclear Information System (INIS)

    Lillethun, E.

    1976-09-01

    Based on the results of high energy proton-proton collisions obtained at the CERN ISR in 1972-73, the production of 'jets' is discussed. Jets in e + e - collisions are also discussed and the parameters 'sphericity' and 'rapidity' are used in analysis of the data. The jets studied have been defined as having at least one particle of high transverse momentum. It is not clear whether the jets represent new physics or are another way of stating that resonances (rho,K*, Δ, N* etc.) are produced with high p(sub T), and that in such production the high transverse momentum must be balanced essentially locally in the collision. (JIW)

  14. The jets of 3C120

    International Nuclear Information System (INIS)

    Axon, D.J.; Pedlar, A.; Unger, S.W.; Meurs, E.J.A.; Ward, M.J.

    1989-01-01

    Core-dominated radio sources associated with quasars are a manifestation of the most extreme form of activity in galactic nuclei. In general, the morphology of their inner radio structure is in the form of a jet detected on only one side of the core; the larger-scale radio emission is relatively symmetric. Superluminal motion in some sources has led to the suggestion that the ejection of radio-emitting material is relativistic and intrinsically two-sided. The apparent one-sidedness of the jets is then explained by relativistic aberration. This persuasive interpretation has not escaped criticism: both physical and statistical arguments have been advanced in favour of one-sided ejection. However, our new optical observations of 3C120, which reveal the details of the interaction between the radio jet and the quiescent gas in the galaxy, offer significant kinematic evidence in favour of the relativistic-beaming hypothesis. (author)

  15. Experimental study of hydrogen jet ignition and jet extinguishment

    International Nuclear Information System (INIS)

    Wierman, R.W.

    1979-04-01

    Two phases are described of an experimental study that investigated: (1) the ignition characteristics of hydrogen--sodium jets, (2) the formation of hydrogen in sodium--humid air atmospheres, and (3) the extinguishment characteristics of burning hydrogen--sodium jets. Test conditions were similar to those postulated for highly-improbable breeder reactor core melt-through accidents and included: jet temperature, jet velocity, jet hydrogen concentration, jet sodium concentration, atmospheric oxygen concentration, and atmospheric water vapor concentration

  16. Genetic Dominance & Cellular Processes

    Science.gov (United States)

    Seager, Robert D.

    2014-01-01

    In learning genetics, many students misunderstand and misinterpret what "dominance" means. Understanding is easier if students realize that dominance is not a mechanism, but rather a consequence of underlying cellular processes. For example, metabolic pathways are often little affected by changes in enzyme concentration. This means that…

  17. Authoritarianism, dominance and assertiveness.

    Science.gov (United States)

    Ray, J J

    1981-08-01

    It is shown that there are definitions of the three constructs of authoritarianism, dominance and assertiveness which read very similarly; so much so that no distinction is immediately evident. It is proposed that authoritarianism might be conceived as aggressive dominance and at least some types of assertiveness as nonaggressive dominance. A new scale of Dominance suitable for general population use was produced, and compared with the existing Ray (1976) behavior inventory of authoritarianism. Both scales showed highly significant correlations with peer rated dominance and submission (the latter being negative in sign) but only the authoritarianism scale showed significant correlations with rated aggressiveness and rigidity. It was concluded that the new definitions could be operationalized into valid scales.

  18. A study of jet handedness in hadronic Zo decays

    International Nuclear Information System (INIS)

    Muller, D.

    1994-05-01

    The authors have searched for inclusive signatures of polarization in hadronic jets from Z 0 → q bar q decays using the open-quote jet handedness close-quote method. They exploited the large polar angle asymmetry induced by the high SLC electron beam polarization to select samples of quark jets and antiquark jets, expected to be left- and right-polarized respectively. They find no evidence for jet handedness in their global sample and set a preliminary upper limit of 7% at 95% C.L. on the magnitude of the analyzing power of this technique. They have used the SLD vertex detector to exclude events containing heavy (b, c) quarks, in which the handedness is expected to be small due to the dominance of decays of spinless mesons. They find no evidence for jet handedness in this high-purity sample of light (u, d and s) quark jets, and set a preliminary upper limit of 11% on the magnitude of the analyzing power in this case. They have investigated several alternative definitions of jet handedness in an attempt to optimize the analyzing power. They find no evidence of jet handedness by any method

  19. Precise predictions for V + jets dark matter backgrounds

    Energy Technology Data Exchange (ETDEWEB)

    Lindert, J.M.; Glover, N.; Morgan, T.A. [University of Durham, Department of Physics, Institute for Particle Physics Phenomenology, Durham (United Kingdom); Pozzorini, S.; Gehrmann, T.; Schoenherr, M. [Universitaet Zuerich, Physik-Institut, Zurich (Switzerland); Boughezal, R. [Argonne National Laboratory, High Energy Physics Division, Argonne, IL (United States); Campbell, J.M. [Fermilab, Batavia, IL (United States); Denner, A. [Universitaet Wuerzburg, Institut fuer Theoretische Physik und Astrophysik, Wuerzburg (Germany); Dittmaier, S.; Maierhoefer, P. [Albert-Ludwigs-Universitaet Freiburg, Physikalisches Institut, Freiburg (Germany); Gehrmann-De Ridder, A. [Universitaet Zuerich, Physik-Institut, Zurich (Switzerland); Institute for Theoretical Physics, ETH, Zurich (Switzerland); Huss, A. [Institute for Theoretical Physics, ETH, Zurich (Switzerland); Kallweit, S.; Mangano, M.L.; Salam, G.P. [CERN, Theoretical Physics Department, Geneva (Switzerland); Mueck, A. [RWTH Aachen University, Institut fuer Theoretische Teilchenphysik und Kosmologie, Aachen (Germany); Petriello, F. [Argonne National Laboratory, High Energy Physics Division, Argonne, IL (United States); Northwestern University, Department of Physics and Astronomy, Evanston, IL (United States); Williams, C. [University at Buffalo, The State University of New York, Department of Physics, Buffalo (United States)

    2017-12-15

    High-energy jets recoiling against missing transverse energy (MET) are powerful probes of dark matter at the LHC. Searches based on large MET signatures require a precise control of the Z(ν anti ν) + jet background in the signal region. This can be achieved by taking accurate data in control regions dominated by Z(l{sup +}l{sup -}) + jet, W(lν) + jet and γ + jet production, and extrapolating to the Z(ν anti ν) + jet background by means of precise theoretical predictions. In this context, recent advances in perturbative calculations open the door to significant sensitivity improvements in dark matter searches. In this spirit, we present a combination of state-of-the-art calculations for all relevant V + jets processes, including throughout NNLO QCD corrections and NLO electroweak corrections supplemented by Sudakov logarithms at two loops. Predictions at parton level are provided together with detailed recommendations for their usage in experimental analyses based on the reweighting of Monte Carlo samples. Particular attention is devoted to the estimate of theoretical uncertainties in the framework of dark matter searches, where subtle aspects such as correlations across different V + jet processes play a key role. The anticipated theoretical uncertainty in the Z(ν anti ν) + jet background is at the few percent level up to the TeV range. (orig.)

  20. Jet physics in ALICE

    International Nuclear Information System (INIS)

    Loizides, C.A.

    2005-01-01

    The ALICE experiment is one of the experiments currently prepared for the Large Hadron Collider (LHC) at CERN, Geneva, starting operation end of 2007. ALICE is dedicated to the research on nucleus-nucleus collisions at ultra-relativistic energies, which addresses the properties of strongly interacting matter under varying conditions of high density and temperature. The conditions provided at the LHC allow significant qualitative improvement with respect to previous studies. In particular, energetic probes, light quarks and gluons, will be abundantly produced. These probes might be identified by their fragmentation into correlated particles, so called jets, of high enough energy to allow full reconstruction of jet properties; even in the underlying heavy-ion environment. Understanding the dependence of high-energy jet production and fragmentation influenced by the dense medium created in the collision region is an open field of active research. Generally, one expects energy loss of the probes due to medium-induced gluon radiation. It is suggested that hadronization products of these, rather soft gluons may be contained within the jet emission cone, resulting in a modification of the characteristic jet fragmentation, as observed via longitudinal and transverse momentum distributions with respect to the direction of the initial parton, as well as of the multiplicity distributions arising from the jet fragmentation. Particle momenta parallel to the jet axis are softened (jet quenching), while transverse to it increased (transverse heating). The present thesis studies the capabilities of the ALICE detectors to measure these jets and quantifies obtainable rates and the quality of jet reconstruction, in both proton-proton and lead-lead collisions at the LHC. In particular, it is addressed whether modification of the jet fragmentation can be detected within the high-particle-multiplicity environment of central lead-lead collisions. (orig.)

  1. Deformations of free jets

    Science.gov (United States)

    Paruchuri, Srinivas

    This thesis studies three different problems. First we demonstrate that a flowing liquid jet can be controllably split into two separate subfilaments through the applications of a sufficiently strong tangential stress to the surface of the jet. In contrast, normal stresses can never split a liquid jet. We apply these results to observations of uncontrolled splitting of jets in electric fields. The experimental realization of controllable jet splitting would provide an entirely novel route for producing small polymeric fibers. In the second chapter we present an analytical model for the bending of liquid jets and sheets from temperature gradients, as recently observed by Chwalek et al. [Phys. Fluids, 14, L37 (2002)]. The bending arises from a local couple caused by Marangoni forces. The dependence of the bending angle on experimental parameters is presented, in qualitative agreement with reported experiments. The methodology gives a simple framework for understanding the mechanisms for jet and sheet bending. In chapter 4 we address the discrepancy between hydrodynamic theory of liquid jets, and the snap-off of narrow liquid jets observed in molecular dynamics (MD) simulations [23]. This has been previously attributed to the significant role of thermal fluctuations in nanofluidic systems. We argue that hydrodynamic description of such systems should include corrections to the Laplace pressure which result from the failure of the sharp interface assumption when the jet diameter becomes small enough. We show that this effect can in principle give rise to jet shapes similar to those observed in MD simulations, even when thermal fluctuations are completely neglected. Finally we summarize an algorithm developed to simulate droplet impact on a smooth surface.

  2. Generalized Power Domination

    OpenAIRE

    Omerzel, Aleš

    2014-01-01

    The power domination problem is an optimization problem that has emerged together with the development of the power networks. It is important to control the voltage and current in all the nodes and links in a power network. Measuring devices are expensive, which is why there is a tendency to place a minimum number of devices in a power network so that the network remains fully supervised. The k-power domination is a generalization of the power domination. The thesis represents the rules of th...

  3. Quark jets, gluon jets and the three-gluon vertex

    International Nuclear Information System (INIS)

    Fodor, Z.

    1989-11-01

    Using hadronic jets in electron-positron annihilation, we suggest a simple and model-independent method to see the differences between quark and gluon jets. We define and analyse special energy dependent moments of jets and choose those which are the most characteristic to the jet type. The method handles the energy of a jet in an adequate way. We discuss new methods using jet flavor tagging, ordinary flavor tagging of a definite quark jet or discrimination between quark and gluon jets, to test the triple-gluon vertex in electron-positron annihilation. An enriched sample of gluon jets, jets with the smallest energy in four-jet events, as well as a continuous tagging variable are also studied. 21 refs., 6 figs. (Author)

  4. HIGH JET EFFICIENCY AND SIMULATIONS OF BLACK HOLE MAGNETOSPHERES

    International Nuclear Information System (INIS)

    Punsly, Brian

    2011-01-01

    This Letter reports on a growing body of observational evidence that many powerful lobe-dominated (FR II) radio sources likely have jets with high efficiency. This study extends the maximum efficiency line (jet power ∼25 times the thermal luminosity) defined in Fernandes et al. so as to span four decades of jet power. The fact that this line extends over the full span of FR II radio power is a strong indication that this is a fundamental property of jet production that is independent of accretion power. This is a valuable constraint for theorists. For example, the currently popular 'no-net-flux' numerical models of black hole accretion produce jets that are two to three orders of magnitude too weak to be consistent with sources near maximum efficiency.

  5. JET Joint Undertaking

    International Nuclear Information System (INIS)

    Keen, B.E.

    1987-03-01

    The paper presents the progress report of the Joint European Torus (JET) Joint Undertaking, 1986. The report contains a survey of the scientific and technical achievements on JET during 1986; the more important articles referred to in this survey are reproduced as appendices to this Report. The last section discusses developments which might improve the overall performance of the machine. (U.K.)

  6. Comments on ICRH current drive in JET

    International Nuclear Information System (INIS)

    Fried, B.; Hellsten, T.; Moreau, D.

    1989-01-01

    To study current drive via the mode-converted slow wave during ICRH an assessment for which plasma compositions and wave number mode conversion from the magnetosonic wave to the slow wave can dominate is made. A simple slab model is used to investigate the competition between mode conversion and minority cyclotron absorption for a deuterium plasma with H + and 3 He 2+ minority species in JET. A 3 He 2+ minority should be more appropriate for mode conversion current drive than H + because the 3 He 2+ concentration can be chosen near its optimum for the ''Budden absorption'' without bringing the ion hybrid resonance and the cyclotron resonance so close that the minority absorption dominates. 3 He 2+ minority also allows operation at toroidal numbers which are characteristic of present JET antennae. (author)

  7. Jet physics at CDF

    International Nuclear Information System (INIS)

    Melese, P.

    1997-05-01

    We present high E T jet measurements from CDF at the Fermilab Tevatron Collider. The incfilusive jet cross section at √s = 1800 GeV with ∼ 5 times more data is compared to the published CDF results, preliminary D0 results, and next-to-leading order QCD predictions. The summation E T cross section is also compared to QCD predictions and the dijet angular distribution is used to place a limit on quark compositeness. The inclusive jet cross section at √s = 630 GeV is compared with that at 1800 GeV to test the QCD predictions for the scaling of jet cross sections with √s. Finally, we present momentum distributions of charged particles in jets and compare them to Modified Leading Log Approximation predictions

  8. Jet physics in ATLAS

    CERN Multimedia

    CERN. Geneva

    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 performance and physics measurements, together with results from new physics searches using the 2011 dataset. They include studies of the underlying event and fragmentation models, measurements of the inclusive jet, dijet and multijet cross sections, parton density functions, heavy flavours, jet shape, mass and substructure. Searches for new physics in monojet, dijet and photon-jet final states are also presented.

  9. Downhill Domination in Graphs

    Directory of Open Access Journals (Sweden)

    Haynes Teresa W.

    2014-08-01

    Full Text Available A path π = (v1, v2, . . . , vk+1 in a graph G = (V,E is a downhill path if for every i, 1 ≤ i ≤ k, deg(vi ≥ deg(vi+1, where deg(vi denotes the degree of vertex vi ∈ V. The downhill domination number equals the minimum cardinality of a set S ⊆ V having the property that every vertex v ∈ V lies on a downhill path originating from some vertex in S. We investigate downhill domination numbers of graphs and give upper bounds. In particular, we show that the downhill domination number of a graph is at most half its order, and that the downhill domination number of a tree is at most one third its order. We characterize the graphs obtaining each of these bounds

  10. Magnetic energy dissipation in force-free jets

    Science.gov (United States)

    Choudhuri, Arnab Rai; Konigl, Arieh

    1986-01-01

    It is shown that a magnetic pressure-dominated, supersonic jet which expands or contracts in response to variations in the confining external pressure can dissipate magnetic energy through field-line reconnection as it relaxes to a minimum-energy configuration. In order for a continuous dissipation to occur, the effective reconnection time must be a fraction of the expansion time. The dissipation rate for the axisymmetric minimum-energy field configuration is analytically derived. The results indicate that the field relaxation process could be a viable mechanism for powering the synchrotron emission in extragalactic jets if the reconnection time is substantially shorter than the nominal resistive tearing time in the jet.

  11. A modified stratified model for the 3C 273 jet

    International Nuclear Information System (INIS)

    Liu Wenpo; Shen Zhiqiang

    2009-01-01

    We present a modified stratified jet model to interpret the observed spectral energy distributions of knots in the 3C 273 jet. Based on the hypothesis of the single index of the particle energy spectrum at injection and identical emission processes among all the knots, the observed difference of spectral shape among different 3C 273 knots can be understood as a manifestation of the deviation of the equivalent Doppler factor of stratified emission regions in an individual knot from a characteristic one. The summed spectral energy distributions of all ten knots in the 3C 273 jet can be well fitted by two components: a low-energy component (radio to optical) dominated by synchrotron radiation and a high-energy component (UV, X-ray and γ-ray) dominated by inverse Compton scattering of the cosmic microwave background. This gives a consistent spectral index of α = 0.88 (S v ∝ v -α ) and a characteristic Doppler factor of 7.4. Assuming the average of the summed spectrum as the characteristic spectrum of each knot in the 3C 273 jet, we further get a distribution of Doppler factors. We discuss the possible implications of these results for the physical properties in the 3C 273 jet. Future GeV observations with GLAST could separate the γ-ray emission of 3C 273 from the large scale jet and the small scale jet (i.e. the core) through measuring the GeV spectrum.

  12. Modeling Polarized Emission from Black Hole Jets: Application to M87 Core Jet

    Directory of Open Access Journals (Sweden)

    Monika Mościbrodzka

    2017-09-01

    Full Text Available We combine three-dimensional general-relativistic numerical models of hot, magnetized Advection Dominated Accretion Flows around a supermassive black hole and the corresponding outflows from them with a general relativistic polarized radiative transfer model to produce synthetic radio images and spectra of jet outflows. We apply the model to the underluminous core of M87 galaxy. The assumptions and results of the calculations are discussed in context of millimeter observations of the M87 jet launching zone. Our ab initio polarized emission and rotation measure models allow us to address the constrains on the mass accretion rate onto the M87 supermassive black hole.

  13. Tests of QCD using jets, bosons plus jets, and top quark production at colliders

    CERN Document Server

    Cossutti, Fabio

    2017-01-01

    Quantum Chromodynamics (QCD) is actively studied at present collidersusing several physics signatures as probes. Results from measurementsdone at LHC, but also from the legacy analyses of Tevatron and HERAdata, are discussed. Jets are the main tool for such investigation, asexperimental evidence for emission of gluons or quark production inQCD-dominated processes. Jet production in multijet events or inassociation with vector bosons is discussed. The investigation of theproduction of heavy quarks, and in particular of the top quark, is ofspecial importance both for the physics implications in the search fornew phenomena and for its unique characteristics from the QCD point ofview.

  14. Jets and QCD

    International Nuclear Information System (INIS)

    Ali, A.; Kramer, G.

    2010-12-01

    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 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 ± ,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.)

  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. Jet angularity measurements for single inclusive jet production

    Science.gov (United States)

    Kang, Zhong-Bo; Lee, Kyle; Ringer, Felix

    2018-04-01

    We study jet angularity measurements for single-inclusive jet production at the LHC. Jet angularities depend on a continuous parameter a allowing for a smooth interpolation between different traditional jet shape observables. We establish a factorization theorem within Soft Collinear Effective Theory (SCET) where we consistently take into account in- and out-of-jet radiation by making use of semi-inclusive jet functions. For comparison, we elaborate on the differences to jet angularities measured on an exclusive jet sample. All the necessary ingredients for the resummation at next-to-leading logarithmic (NLL) accuracy are presented within the effective field theory framework. We expect semiinclusive jet angularity measurements to be feasible at the LHC and we present theoretical predictions for the relevant kinematic range. In addition, we investigate the potential impact of jet angularities for quark-gluon discrimination.

  17. Numerical study of jet noise radiated by turbulent coherent structures

    Energy Technology Data Exchange (ETDEWEB)

    Bastin, F.

    1995-08-01

    a numerical approach of jet mixing noise prediction is presented, based on the assumption that the radiated sound field is essentially due to large-scale coherent turbulent structures. A semi-deterministic turbulence modelling is used to obtain the flow coherent fluctuations. This model is derived from the k-{epsilon} model and validated on the 2-D compressible shear layer case. Three plane jets at Mach 0.5, 1.33 and 2 are calculated. The semi-deterministic modelling yields a realistic unsteady representation of plane jets but not appropriate for axisymmetric jet computations. Lighthill`s analogy is used to estimate the noise radiated by the flow. Three integral formulations of the theory are compared and the most suitable one is expressed in space-time Fourier space. This formulation is associated to a geometrical interpretation of acoustic computations in (k, {omega}) plane. The only contribution of coherent structures cannot account for the high-frequency radiation of a subsonic jet and thus, the initial assumption is not verified in the subsonic range. The interpretation of Lighthill`s analogy in (k, {omega}) plane allows to conclude that the missing high-frequency components are due to the inner structure of the coherent motion. For supersonic jets, full acoustic spectra are obtained, at least in the forward arc where the dominant radiation is emitted. For the fastest jet (M = 2), no Mach waves are observed, which may be explained by a ratio of the structures convection velocity to the jet exit velocity lower in plane than in circular jets. This point is confirmed by instability theory calculations. Large eddy simulations (LES) were performed for subsonic jets. Data obtained in the plane jet case show that this technique allows only a slight improvement of acoustic results. To obtain a satisfactory high-frequency radiation, very fine grids should be considered, and the 2-D approximation could not be justified anymore. (Abstract Truncated)

  18. Intermediate PT jet spectrometers

    International Nuclear Information System (INIS)

    Gutay, L.J.; Koltick, D.; Hauptman, J.; Stork, D.; Theodosiou, G.

    1988-01-01

    A design is presented for a limited solid angle, high resolution double arm spectrometer at 90 degree to the begin, with a vertex detector and particle identification in both arms. The jet arm is designed to accept a complete jet, and identify its substructure of sub-jets, hadrons, and leptons. The particle arm would measure e,π,K,p ratios for P T 0 to the beam for the purpose of tagging Higgs production by boson fusion, 1 gauge boson (WW, ZZ, and WZ) scattering 2 L, and other processes involving the interactions of virtual gauge bosons

  19. Latest results from JET

    International Nuclear Information System (INIS)

    Bickerton, R.J.

    1989-01-01

    The Joint European Torus (JET) is a large tokamak designed with the essential objective of obtaining and studying plasmas with parameters close to those envisaged for an eventual power-generating, nuclear-fusion reactor. JET is situated on a site near Abingdon, Oxon, UK. JET is the largest single project of the nuclear fusion research programme of the European Atomic Energy Community (EURATOM). The tokamak started operation in mid 1983 after a five year construction period. The scientific and technical results achieved so far are summarised in this article. (orig.)

  20. Oscillating acoustic streaming jet

    International Nuclear Information System (INIS)

    Moudjed, Brahim; Botton, Valery; Henry, Daniel; Millet, Severine; Ben Hadid, Hamda; Garandet, Jean-Paul

    2014-01-01

    The present paper provides the first experimental investigation of an oscillating acoustic streaming jet. The observations are performed in the far field of a 2 MHz circular plane ultrasound transducer introduced in a rectangular cavity filled with water. Measurements are made by Particle Image Velocimetry (PIV) in horizontal and vertical planes near the end of the cavity. Oscillations of the jet appear in this zone, for a sufficiently high Reynolds number, as an intermittent phenomenon on an otherwise straight jet fluctuating in intensity. The observed perturbation pattern is similar to that of former theoretical studies. This intermittently oscillatory behavior is the first step to the transition to turbulence. (authors)

  1. b-JETS AT LHCb

    CERN Document Server

    Coco, Victor

    2008-01-01

    LHCb 1 is a LHC experiment dedicated to pre-jets. LHCh detector is a one arm spectrometer. It covers the forward region of interaction point, from 30 mrad to 300 (250) mrad in bending (non-bending) plane. The choice of such a limited acceptance is motivated by the fact that most of the 500 µb correlated bb pairs are produced in this region. LHCb experiment will take data at a luminosity of 2 x ID32cm-2s-1, where bunch crossing are dominated by single pp interactions. Good particle identification, excellent tracking and vcrtcxing arc needed for B physic mcasurmcnts. Expected resolution on track momentum is about bp/p = 0.35% around 10 GeV /c to bp/p = 0.55% around 140 GeV /c. Impact parameter resolution is expected to be aIP = 14µm + 35µm/p-r.

  2. 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

  3. Jet lag prevention

    Science.gov (United States)

    ... lose time. Symptoms of jet lag include: Trouble falling asleep or waking up Tiredness during the day ... at your destination. For longer trips, before you leave, try to adapt to the time schedule of ...

  4. Intermonsoonal equatorial jets

    Digital Repository Service at National Institute of Oceanography (India)

    Muraleedharan, P.M.

    , respectively. Hydrographic features and transport computations favour a well developed equatorial jet during both seasons. The net surface eastward and subsurface westward flows are well balanced during the premonsoon transition period and appear...

  5. Iron dominated magnets

    International Nuclear Information System (INIS)

    Fischer, G.E.

    1985-07-01

    These two lectures on iron dominated magnets are meant for the student of accelerator science and contain general treatments of the subjects design and construction. The material is arranged in the categories: General Concepts and Cost Considerations, Profile Configuration and Harmonics, Magnetic Measurements, a few examples of ''special magnets'' and Materials and Practices. Extensive literature is provided

  6. Bestsellers dominate the market

    Energy Technology Data Exchange (ETDEWEB)

    Koenemann, Detlef

    2010-07-01

    The strong market growth of the past years has led to certain turbine types achieving very high numbers of units sold. As a result, the leading manufacturers are becoming ever more dominant, and many smaller manufacturers are beng required to seek their success in market niches. (orig.)

  7. Iron dominated magnets

    Energy Technology Data Exchange (ETDEWEB)

    Fischer, G.E.

    1985-07-01

    These two lectures on iron dominated magnets are meant for the student of accelerator science and contain general treatments of the subjects design and construction. The material is arranged in the categories: General Concepts and Cost Considerations, Profile Configuration and Harmonics, Magnetic Measurements, a few examples of ''special magnets'' and Materials and Practices. Extensive literature is provided.

  8. Searching for world domination

    CERN Multimedia

    Quillen, E

    2004-01-01

    "Optimists might believe Microsoft suffered a setback last week that will impede its progress toward world domination, but I suspect the company has already found a way to prevail. At issue before the European Union was Microsoft's bundling of its Windows Media Player with its operating system" (1 page)

  9. The JET divertor coil

    International Nuclear Information System (INIS)

    Last, J.R.; Froger, C.; Sborchia, C.

    1989-01-01

    The divertor coil is mounted inside the Jet vacuum vessel and is able to carry 1 MA turns. It is of conventional construction - water cooled copper, epoxy glass insulation -and is contained in a thin stainless steel case. The coil has to be assembled, insulated and encased inside the Jet vacuum vessel. A description of the coil is given, together with technical information (including mechanical effects on the vacuum vessel), an outline of the manufacture process and a time schedule. (author)

  10. Pellet injectors for JET

    International Nuclear Information System (INIS)

    Andelfinger, C.; Buechl, K.; Lang, R.S.; Schilling, H.B.; Ulrich, M.

    1981-09-01

    Pellet injection for the purpose of refuelling and diagnostic of fusion experiments is considered for the parameters of JET. The feasibility of injectors for single pellets and for quasistationary refuelling is discussed. Model calculations on pellet ablation with JET parameters show the required pellet velocity ( 3 ). For single pellet injection a light gas gun, for refuelling a centrifuge accelerator is proposed. For the latter the mechanical stress problems are discussed. Control and data acquisition systems are outlined. (orig.)

  11. Protostellar Jets in Context

    CERN Document Server

    Tsinganos, Kanaris; Stute, Matthias

    2009-01-01

    This volume contains the proceedings of the Conference Protostellar Jets in Context held by the JETSET Marie Curie Research Training Network in July 2008. This meeting not only served to showcase some of the network's achievements but was also a platform to hear from, discuss and debate the recent findings of world-class astrophysicists in the field of protostellar jet research. Jets from young stars are of course not an isolated astrophysical phenomenon. It is known that objects as diverse as young brown dwarfs, planetary nebulae, symbiotic stars, micro-quasars, AGN, and gamma-ray bursters produce jets. Thus in a series of talks, protostellar jets were put in context by comparing them with their often much larger brethren and also by considering the ubiquitous accretion disks that seem to be necessary for their formation. With this spectrum of contributions on observations and the theory of astrophysical jets and accretion disks, this book serves as a comprehensive reference work for researchers and students...

  12. Jet supercooling and molecular jet spectroscopy

    International Nuclear Information System (INIS)

    Wharton, L.; Levy, D.

    1979-01-01

    The marriage of the laser and the seeded supersonic jet has generated a family of new optical spectroscopic results. We shall discuss the essential features of the technique and some results. The results will include structural and dynamical views of NO 2 , NaAr, and I 2 -noble gas complexes. The extension of the method to heavier systems is illustrated with free base phthalocyanine

  13. Nonlinear interaction model of subsonic jet noise.

    Science.gov (United States)

    Sandham, Neil D; Salgado, Adriana M

    2008-08-13

    Noise generation in a subsonic round jet is studied by a simplified model, in which nonlinear interactions of spatially evolving instability modes lead to the radiation of sound. The spatial mode evolution is computed using linear parabolized stability equations. Nonlinear interactions are found on a mode-by-mode basis and the sound radiation characteristics are determined by solution of the Lilley-Goldstein equation. Since mode interactions are computed explicitly, it is possible to find their relative importance for sound radiation. The method is applied to a single stream jet for which experimental data are available. The model gives Strouhal numbers of 0.45 for the most amplified waves in the jet and 0.19 for the dominant sound radiation. While in near field axisymmetric and the first azimuthal modes are both important, far-field sound is predominantly axisymmetric. These results are in close correspondence with experiment, suggesting that the simplified model is capturing at least some of the important mechanisms of subsonic jet noise.

  14. Novel jet observables from machine learning

    Science.gov (United States)

    Datta, Kaustuv; Larkoski, Andrew J.

    2018-03-01

    Previous studies have demonstrated the utility and applicability of machine learning techniques to jet physics. In this paper, we construct new observables for the discrimination of jets from different originating particles exclusively from information identified by the machine. The approach we propose is to first organize information in the jet by resolved phase space and determine the effective N -body phase space at which discrimination power saturates. This then allows for the construction of a discrimination observable from the N -body phase space coordinates. A general form of this observable can be expressed with numerous parameters that are chosen so that the observable maximizes the signal vs. background likelihood. Here, we illustrate this technique applied to discrimination of H\\to b\\overline{b} decays from massive g\\to b\\overline{b} splittings. We show that for a simple parametrization, we can construct an observable that has discrimination power comparable to, or better than, widely-used observables motivated from theory considerations. For the case of jets on which modified mass-drop tagger grooming is applied, the observable that the machine learns is essentially the angle of the dominant gluon emission off of the b\\overline{b} pair.

  15. Characteristics of strongly-forced turbulent jets and non-premixed jet flames

    Energy Technology Data Exchange (ETDEWEB)

    Lakshminarasimhan, K.; Ezekoye, O.A. [University of Texas at Austin, Department of Mechanical Engineering, Austin, TX (United States); Clemens, N.T. [University of Texas at Austin, Department of Aerospace Engineering and Engineering Mechanics, Austin, TX (United States)

    2006-10-15

    Previous researchers have demonstrated that strong pulsations of the fuel flow rate can significantly reduce the flame length and luminosity of laminar/transitional non-premixed jet flames. The physical mechanisms responsible for these changes are investigated experimentally in acoustically-forced jet flows where the peak velocity fluctuations are up to eight times the mean flow velocity. Both reacting and non-reacting flows were studied and Reynolds numbers, based on the mean flow properties, ranged from 800 to 10,000 (corresponding to peak Reynolds numbers of 1,450-23,000), and forcing frequencies ranged from 290 to 1,140 Hz. Both the first and second organ-pipe resonance modes of the fuel delivery tube were excited to obtain these frequencies. An analysis of the acoustic forcing characteristics within the resonance tube is provided in order to understand the source of the high amplitude forcing. Flow visualization of jets with first resonant forcing confirms the presence of large-scale coherent vortices and strong reverse flow near the exit of the fuel tube. With second-resonant forcing, however, vortices are not emitted from the tube as they are drawn back into the fuel tube before they can fully form. Increased fine-scale turbulence is associated with both resonant cases, but particularly at second resonance. The power spectra of the velocity fluctuations for a resonantly pulsed jet show the presence of an inertial subrange indicating that the flow becomes fully turbulent even for mean-Reynolds-number jets that are nominally laminar. It is shown that these pulsed jet flows exhibit strong similarities to synthetic jets and that the Strouhal number, based on the maximum velocity at the fuel tube exit, is the dominant parameter for scaling these flows. The Strouhal number determines the downstream location where the coherent vortices breakdown, and is found to provide better collapse of flame length data (both current and previous) than other parameters that have

  16. Public owners will dominate

    International Nuclear Information System (INIS)

    Bakken, Stein Arne

    2003-01-01

    In ten years there will still be a dominating public ownership in the energy supply sector in Norway. Statkraft will be the big actor. Norway will then be integrated in an European power market through more cables and the power price will be lower and more stable. The market will be important, but within frames set by the politicians. This article quotes the views of two central figures in the energy sector on the energy supply industry in 2014

  17. Production of vector bosons in association with jets in ATLAS

    CERN Document Server

    Meoni, Evelin; The ATLAS collaboration

    2017-01-01

    Measurements of the production of jets in association with a W/Z boson in proton–proton collisions are presented using data collected by the ATLAS experi- ment at LHC at √s = 8 and 13 TeV. Several kinematic regimes are explored with various approaches to probe di erent aspects of these processes. The di erential cross sections of a Z boson in association with jets with pT > 30 GeV and |y| <2.5 at √s = 13 TeV are measured in a ducial phase space, probing strong interactions that completely dominate in these processes, while measurementsofaWbosoninassociationwithatleasttwojetsathighpT andhigh di-jet invariant mass, where the electroweak production is enhanced, are performed with √s = 8 TeV data. Angular distributions in W+jets events with high pT jets are also measured at √s = 8 TeV focusing on small angular separation between the jets and the W decay products, where contributions from real W emission are expected large. Finally a measurement of the splitting scales occurring in the kt jet-clusteri...

  18. Numerical analyses of flashing jet structure and droplet size characteristics

    International Nuclear Information System (INIS)

    Duan Riqiang; Jiang Shengyao; Koshizuka, Seiichi; Oka, Yoshiaki; Yamaguchi, Akira; Takata, Takashi

    2006-01-01

    In this paper, flashing jets are numerically simulated using the MPS method. The boiling mode for flashing is identified as surface boiling mode, based on the postulation of jets from a short nozzle under high depressurization. The Homogeneous Non-equilibrium Relaxation Model (HRM) is used for calculating the evaporation rate of flashing. The numerical simulation results show that flashing jets comprise an inner intact core which is surrounded by two-phase droplet flow. The effect of degree of superheat on the jet topological geometry is investigated. With increasing degree of superheat, the topological shape of flashing jets evolves from cylindrical core for low degree of superheat to cone-shaped core for high degree of superheat, and meanwhile the extinction length comes to decrease and tends asymptotically constant as the injection temperature approaches the saturation temperature corresponding to the injection pressure. The analyses of the droplet size distribution engendered from primary breakup of flashing jets show that: two peaks exist for droplet size distribution at lower degree of superheat; however, merely one peak for higher degree of superheat. From droplet size distribution, it is revealed that the primary breakup mechanism of flashing jets can be attributed to dominant mechanical breakup mode plus enhancement via surface evaporation. (author)

  19. JET Joint Undertaking

    International Nuclear Information System (INIS)

    Keen, B.E.; Kupschus, P.

    1984-09-01

    The report is in sections, as follows. (1) Introduction and summary. (2) A brief description of the origins of the JET Project within the EURATOM fusion programme and the objectives and aims of the device. The basic JET design and the overall philosophy of operation are explained and the first six months of operation of the machine are summarised. The Project Team Structure adopted for the Operation Phase is set out. Finally, in order to set JET's progress in context, other large tokamaks throughout the world and their achievements are briefly described. (3) The activities and progress within the Operation and Development Department are set out; particularly relating to its responsibilities for the operation and maintenance of the tokamak and for developing the necessary engineering equipment to enhance the machine to full performance. (4) The activities and progress within the Scientific Department are described; particularly relating to the specification, procurement and operation of diagnostic equipment; definition and execution of the programme; and the interpretation of experimental results. (5) JET's programme plans for the immediate future and a broad outline of the JET Development Plan to 1990 are given. (author)

  20. Dominating biological networks.

    Directory of Open Access Journals (Sweden)

    Tijana Milenković

    Full Text Available Proteins are essential macromolecules of life that carry out most cellular processes. Since proteins aggregate to perform function, and since protein-protein interaction (PPI networks model these aggregations, one would expect to uncover new biology from PPI network topology. Hence, using PPI networks to predict protein function and role of protein pathways in disease has received attention. A debate remains open about whether network properties of "biologically central (BC" genes (i.e., their protein products, such as those involved in aging, cancer, infectious diseases, or signaling and drug-targeted pathways, exhibit some topological centrality compared to the rest of the proteins in the human PPI network.To help resolve this debate, we design new network-based approaches and apply them to get new insight into biological function and disease. We hypothesize that BC genes have a topologically central (TC role in the human PPI network. We propose two different concepts of topological centrality. We design a new centrality measure to capture complex wirings of proteins in the network that identifies as TC those proteins that reside in dense extended network neighborhoods. Also, we use the notion of domination and find dominating sets (DSs in the PPI network, i.e., sets of proteins such that every protein is either in the DS or is a neighbor of the DS. Clearly, a DS has a TC role, as it enables efficient communication between different network parts. We find statistically significant enrichment in BC genes of TC nodes and outperform the existing methods indicating that genes involved in key biological processes occupy topologically complex and dense regions of the network and correspond to its "spine" that connects all other network parts and can thus pass cellular signals efficiently throughout the network. To our knowledge, this is the first study that explores domination in the context of PPI networks.

  1. [Autosomal dominant polycystic kidney].

    Science.gov (United States)

    Jorge Adad, S; Estevão Barbosa, M; Fácio Luíz, J M; Furlan Rodrigues, M C; Iwamoto, S

    1996-01-01

    A 48-year-old male had autosomic dominant polycystic kidneys with dimensions, to the best of our knowledge, never previously reported; the right kidney weighed 15,100 g and measured 53 x 33 x 9cm and the left one 10.200 g and 46 x 21 x 7cm, with cysts measuring up to 14cm in diameter. Nephrectomy was done to control persistent hematuria and to relief disconfort caused by the large kidneys. The renal function is stable four years after transplantation.

  2. Two-loop beam and soft functions for rapidity-dependent jet vetoes

    Energy Technology Data Exchange (ETDEWEB)

    Gangal, Shireen [Theory Group, Deutsches Elektronen-Synchrotron (DESY),Notkestraße 85, D-22607 Hamburg (Germany); Gaunt, Jonathan R. [Nikhef Theory Group and VU University Amsterdam,De Boelelaan 1081, NL-1081 HV Amsterdam (Netherlands); Stahlhofen, Maximilian [PRISMA Cluster of Excellence, Institute of Physics, Johannes Gutenberg University,Staudingerweg 7, D-55128 Mainz (Germany); Tackmann, Frank J. [Theory Group, Deutsches Elektronen-Synchrotron (DESY),Notkestraße 85, D-22607 Hamburg (Germany)

    2017-02-06

    Jet vetoes play an important role in many analyses at the LHC. Traditionally, jet vetoes have been imposed using a restriction on the transverse momentum p{sub Tj} of jets. Alternatively, one can also consider jet observables for which p{sub Tj} is weighted by a smooth function of the jet rapidity y{sub j} that vanishes as |y{sub j}|→∞. Such observables are useful as they provide a natural way to impose a tight veto on central jets but a looser one at forward rapidities. We consider two such rapidity-dependent jet veto observables, T{sub Bj} and T{sub Cj}, and compute the required beam and dijet soft functions for the jet-vetoed color-singlet production cross section at two loops. At this order, clustering effects from the jet algorithm become important. The dominant contributions are computed fully analytically while corrections that are subleading in the limit of small jet radii are expressed in terms of finite numerical integrals. Our results enable the full NNLL{sup ′} resummation and are an important step towards N{sup 3}LL resummation for cross sections with a T{sub Bj} or T{sub Cj} jet veto.

  3. A Comprehensive Analysis of Jet Quenching via a Hybrid Strong/Weak Coupling Model for Jet-Medium Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Casalderrey-Solana, Jorge [Departament d' Estructura i Constituents de la Matèria and Institut de Ciències del Cosmos (ICCUB), Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona (Spain); Rudolf Peierls Centre for Theoretical Physics, University of Oxford, 1 Keble Road, Oxford OX1 3NP (United Kingdom); Gulhan, Doga Can [Laboratory for Nuclear Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Milhano, José Guilherme [CENTRA, Instituto Superior Técnico, Universidade de Lisboa, Av. Rovisco Pais, P-1049-001 Lisboa (Portugal); Physics Department, Theory Unit, CERN, CH-1211 Genève 23 (Switzerland); Pablos, Daniel [Departament d' Estructura i Constituents de la Matèria and Institut de Ciències del Cosmos (ICCUB), Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona (Spain); Rajagopal, Krishna [Laboratory for Nuclear Science and Department of Physics, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States)

    2016-12-15

    Within a hybrid strong/weak coupling model for jets in strongly coupled plasma, we explore jet modifications in ultra-relativistic heavy ion collisions. Our approach merges the perturbative dynamics of hard jet evolution with the strongly coupled dynamics which dominates the soft exchanges between the fast partons in the jet shower and the strongly coupled plasma itself. We implement this approach in a Monte Carlo, which supplements the DGLAP shower with the energy loss dynamics as dictated by holographic computations, up to a single free parameter that we fit to data. We then augment the model by incorporating the transverse momentum picked up by each parton in the shower as it propagates through the medium, at the expense of adding a second free parameter. We use this model to discuss the influence of the transverse broadening of the partons in a jet on intra-jet observables. In addition, we explore the sensitivity of such observables to the back-reaction of the plasma to the passage of the jet.

  4. JET Joint Undertaking

    International Nuclear Information System (INIS)

    Keen, B.E.

    1986-03-01

    This is an overview summary of the scientific and technical advances at JET during the year 1985, supplemented by appendices of detailed contributions (in preprint form) of eight of the more important JET articles produced during that year. It is aimed not only at specialists and experts but also at a more general scientific community. Thus there is a brief summary of the background to the project, a description of the basic objectives of JET and the principle design features of the machine. The new structure of the Project Team is also explained. Developments and future plans are included. Improvements considered are those which are designed to overcome certain limitations encountered generally on Tokamaks, particularly those concerned with density limits, with plasma MHD behaviour, with impurities and with plasma transport. There is also a complete list of articles, reports and conference papers published in 1985 - there are 167 such items listed. (UK)

  5. A turbulent jet in crossflow analysed with proper orthogonal decomposition

    DEFF Research Database (Denmark)

    Meyer, Knud Erik; Pedersen, Jakob Martin; Özcan, Oktay

    2007-01-01

    and pipe diameter was 2400 and the jet to crossflow velocity ratios were R = 3.3 and R = 1.3. The experimental data have been analysed by proper orthogonal decomposition (POD). For R = 3.3, the results in several different planes indicate that the wake vortices are the dominant dynamic flow structures...

  6. Jet shapes in hadron and electron colliders

    International Nuclear Information System (INIS)

    Wainer, N.

    1993-05-01

    High energy jets are observed both in hadronic machines like the Tevatron and electron machines like LEP. These jets have an extended structure in phase space which can be measured. This distribution is usually called the jet shape. There is an intrinsic relation between jet variables, like energy and direction, the jet algorithm used, and the jet shape. Jet shape differences can be used to separate quark and gluon jets

  7. Galaxies with jet streams

    International Nuclear Information System (INIS)

    Breuer, R.

    1981-01-01

    Describes recent research work on supersonic gas flow. Notable examples have been observed in cosmic radio sources, where jet streams of galactic dimensions sometimes occur, apparently as the result of interaction between neighbouring galaxies. The current theory of jet behaviour has been convincingly demonstrated using computer simulation. The surprisingly long-term stability is related to the supersonic velocity, and is analagous to the way in which an Appollo spacecraft re-entering the atmosphere supersonically is protected by the gas from the burning shield. (G.F.F.)

  8. 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

  9. Jet pump assisted artery

    Science.gov (United States)

    1975-01-01

    A procedure for priming an arterial heat pump is reported; the procedure also has a means for maintaining the pump in a primed state. This concept utilizes a capillary driven jet pump to create the necessary suction to fill the artery. Basically, the jet pump consists of a venturi or nozzle-diffuser type constriction in the vapor passage. The throat of this venturi is connected to the artery. Thus vapor, gas, liquid, or a combination of the above is pumped continuously out of the artery. As a result, the artery is always filled with liquid and an adequate supply of working fluid is provided to the evaporator of the heat pipe.

  10. Interaction between plasma synthetic jet and subsonic turbulent boundary layer

    Science.gov (United States)

    Zong, Haohua; Kotsonis, Marios

    2017-04-01

    exhibits a prominent spatiotemporal behaviour. The residence time of the CVP is estimated as the jet duration time, while the maximum extent of the affected flow in the three coordinate directions (x, y, and z) is approximately 32D, 8.5D, and 10D, respectively. An extremely high level of turbulent kinetic energy production is shown in the jet shear-layer, front vortex ring, and CVP, of which the contribution of the streamwise Reynolds normal stress is dominant. Finally, a conceptual model of the interaction between the PSJ and the TBL is proposed.

  11. Turbulent jet in confined counterflow

    Indian Academy of Sciences (India)

    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 ...

  12. Elucidating Jet Energy Loss Using Jets Prospects from ATLAS

    CERN Document Server

    Grau, N

    2009-01-01

    Jets at the LHC are expected to provide the testing ground for studying QCD energy loss. In this contribution, we briefly outline the strategy that will be used to measure jets in ATLAS and how we will go about studying energy loss. We describe the utility of measuring the jet $R_{AA}$, the fragmentation function, and heavy flavor jets. Utilizing the collision energy provided by the LHC and the nearly hermetic and highly segmented calorimeter, ATLAS is expected to make important contributions to the understanding of parton energy loss using fully reconstructed jets.

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

    International Nuclear Information System (INIS)

    Grau, N.

    2009-01-01

    Jets at the LHC are expected to provide the testing ground for studying QCD energy loss. In this contribution, we briefly outline the strategy that will be used to measure jets in ATLAS and how we will go about studying energy loss. We describe the utility of measuring the jet R AA , the fragmentation function, and heavy flavor jets. Utilizing the collision energy provided by the LHC and the nearly hermetic and highly segmented calorimeter, ATLAS is expected to make important contributions to the understanding of parton energy loss using fully reconstructed jets.

  14. JET joint undertaking

    International Nuclear Information System (INIS)

    1984-06-01

    JET began operations on 25 June 1983. This annual report contains administrative information and a general review of scientific and technical developments. Among them are vacuum systems, toroidal and poloidal field systems, power supplies, neutral beam heating, radiofrequency heating, remote handling, tritium handling, control and data acquisition systems and diagnostic systems

  15. Triton burnup in JET

    International Nuclear Information System (INIS)

    Chipsham, E.; Jarvis, O.N.; Sadler, G.

    1989-01-01

    Triton burnup measurements have been made at JET using time-integrated copper activation and time-resolved silicon detector techniques. The results confirm the classical nature of both the confinement and the slowing down of the 1 MeV tritons in a plasma. (author) 8 refs., 3 figs

  16. Vortex diode jet

    Science.gov (United States)

    Houck, Edward D.

    1994-01-01

    A fluid transfer system that combines a vortex diode with a jet ejector to transfer liquid from one tank to a second tank by a gas pressurization method having no moving mechanical parts in the fluid system. The vortex diode is a device that has a high resistance to flow in one direction and a low resistance to flow in the other.

  17. Jets in Active Galaxies

    Indian Academy of Sciences (India)

    which are rapidly rotating neutron stars emitting narrow beams of radiation. Images of ... rized into starburst galaxies and AGN powered by SMBHs. The ..... swer lies in the relativistic motion of the jets which boosts the flux density of .... radio cores, detection of ... to as synchrotron self-Compton or SSC, or those of the cosmic.

  18. LHCb jet reconstruction

    International Nuclear Information System (INIS)

    Francisco, Oscar; Rangel, Murilo; Barter, William; Bursche, Albert; Potterat, Cedric; Coco, Victor

    2012-01-01

    Full text: 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 X 10 32 cm -2 s -1 and the integrated luminosity reached the value of 1,02fb -1 on the LHCb. The jet reconstruction is fundamental to observe events that can be used to test perturbative 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 ηX φ and on the transverse momentum of particles. To maximize the energy resolution all information about the trackers and the colorimeters are used on the LHCb experiment to create objects called particle flow objects that are used as input to anti-kt algorithm. The LHCb is specially interesting for jets studies because its η region is complementary to the others main experiments on LHC. We will present the first results of jet reconstruction using 2011 LHCb data. (author)

  19. LHCb jet reconstruction

    Energy Technology Data Exchange (ETDEWEB)

    Francisco, Oscar; Rangel, Murilo [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil); Barter, William [University of Cambridge, Cambridge (United Kingdom); Bursche, Albert [Universitat Zurich, Zurich (Switzerland); Potterat, Cedric [Universitat de Barcelona, Barcelona (Spain); Coco, Victor [Nikhef National Institute for Subatomic Physics, Amsterdam (Netherlands)

    2012-07-01

    Full text: 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 X 10{sup 32} cm{sup -2}s{sup -1} and the integrated luminosity reached the value of 1,02fb{sup -1} on the LHCb. The jet reconstruction is fundamental to observe events that can be used to test perturbative 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}X {phi} and on the transverse momentum of particles. To maximize the energy resolution all information about the trackers and the colorimeters are used on the LHCb experiment to create objects called particle flow objects that are used as input to anti-kt algorithm. The LHCb is specially interesting for jets studies because its {eta} region is complementary to the others main experiments on LHC. We will present the first results of jet reconstruction using 2011 LHCb data. (author)

  20. Fastener investigation in JET

    Energy Technology Data Exchange (ETDEWEB)

    Bunting, P., E-mail: patrick.bunting@ccfe.ac.uk; Thompson, V.; Riccardo, V.

    2016-11-15

    Highlights: • Experimental work to identify the cause of a bolt seizure inside the JET vessel. • Taguchi method used to reduce tests to 16 while covering 5 parameters. • Experimental work was unable to reproduce bolt seizure. • Thread contamination had little effect on the bolt performance. - Abstract: JET is an experimental fusion reactor consisting of magnetically confined, high temperature plasma inside a large ultra-high vacuum chamber. The inside of the chamber is protected from the hot plasma with tiles made from beryllium, tungsten, carbon composites and other materials bolted to the vessel wall. The study was carried out in response to a JET fastener seizing inside the vacuum vessel. The following study looks at characterising the magnitude of the individual factors affecting the fastener break away torque. This was carried out using a statistical approach, the Taguchi method: isolating the net effect of individual factors present in a series of tests [1](Grove and Davis, 1992). Given the severe environment within the JET vessel due to the combination of heat, ultra-high vacuum and the high contact pressure in bolt threads, the contributions of localised diffusion bonding is assessed in conjunction with various combinations of bolt and insert material.

  1. Jet Inlet Efficiency

    Science.gov (United States)

    2013-08-08

    AFRL-RW-EG-TR-2014-044 Jet Inlet Efficiency Nigel Plumb Taylor Sykes-Green Keith Williams John Wohleber Munitions Aerodynamics Sciences...CONTRACT NUMBER N/A 5b. GRANT NUMBER N/A 5c. PROGRAM ELEMENT NUMBER N/A 6. AUTHOR(S) Nigel Plumb Taylor Sykes-Green Keith Williams John

  2. Abrasive water jet cutting

    International Nuclear Information System (INIS)

    Leist, K.J.; Funnell, G.J.

    1988-01-01

    In the process of selecting a failed equipment cut-up tool for the process facility modifications (PFM) project, a system using an abrasive water jet (AWJ) was developed and tested for remote disassembly of failed equipment. It is presented in this paper

  3. 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.

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

    International Nuclear Information System (INIS)

    Cogan, Josh; Kagan, Michael; Strauss, Emanuel; Schwarztman, Ariel

    2015-01-01

    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.

  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. Jet substructure using semi-inclusive jet functions in SCET

    International Nuclear Information System (INIS)

    Kang, Zhong-Bo; Ringer, Felix; 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 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_i"h(z=ω_J/ω,z_h=ω_h/ω_J,ω_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_J), and the hadron h (ω_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_i"h(z,z_h,ω_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_R) accuracy. In combination with the fixed NLO calculation, we obtain NLO+NLL_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.

  7. Non-inductively driven currents in JET

    International Nuclear Information System (INIS)

    Challis, C.D.; Cordey, J.G.; Hamnen, H.; Stubberfield, P.M.; Christiansen, J.P.; Lazzaro, E.; Muir, D.G.; Stork, D.; Thompson, E.

    1989-01-01

    Neutral beam heating data from JET have been analysed in detail to determine what proportion of the current is driven non-inductively. It is found that in low density limiter discharges, currents of the order of 0.5 MA are driven, while in H-mode plasmas currents of the order of 0.7 MA are measured. These measured currents are found to be in reasonable agreement with theoretical predictions based on neoclassical models. In low density plasmas the beam driven current is large while the neoclassical bootstrap current dominates H-mode plasmas. (author). 19 refs, 11 figs

  8. Deciphering jet quenching with JEWEL

    CERN Multimedia

    CERN. Geneva

    2018-01-01

    In heavy ion collisions jets arising from the fragmentation of hard quarks and gluons experience strong modifications due to final state re-scattering. This so-called jet quenching is related to the emergence of collectivity and equilibration in QCD. I will give an introduction to jet quenching and its modeling in JEWEL, a Monte Carlo implementation of a dynamical model for jet quenching. I will then discuss examples highlighting how JEWEL can be used to elucidate the physical mechanisms relevant for jet quenching.  

  9. Structure of pulsed plasma jets

    International Nuclear Information System (INIS)

    Cavolowsky, J.A.

    1987-01-01

    A pulsed plasma jet is a turbulent, inhomogeneous fluid mechanical discharge capable of initiating and enhancing combustion. Having shown the ability to ignite lean fuel mixtures, it now offers the potential for real-time control of combustion processes. This study explored the fluid-mechanical and chemical properties of such jets. The fluid-mechanical structure of the jet was examined using two optical diagnostic techniques. Self-light streak photography provided information on the motion of luminous gas particles in its core. It revealed that plasma jets behave either totally subsonic or embody a supersonic core. The turbulent, thermal evolution of the jet was explored using high-speed-laser schlieren cinematography. By examining plasma jet generators with both opaque and transparent plasma cavities, detailed information on plasma formation and jet structure, beginning with the electric arc discharge in the cavity, was obtained. These records revealed the production of thermal stratifications in the cavity that could account for the plasma particles in the jet core. After the electrical discharges ceased, the turbulent jet behaved as a self-similar plume. Molecular-beam mass spectrometry was used to determine temperature and species concentration in the jet. Both non-combustible and combustible jets were studied

  10. Jet pT resummation in Higgs production at NNLL'+NNLO

    International Nuclear Information System (INIS)

    Stewart, Iain W.; Tackmann, Frank J.; Walsh, Jonathan R.; Zuberi, Saba

    2013-07-01

    We present predictions for Higgs production via gluon fusion with a p T veto on jets and with the resummation of jet-veto logarithms at NNLL'+NNLO order. These results incorporate explicit O(α s 2 ) calculations of soft and beam functions, which include the dominant dependence on the jet radius R. In particular the NNLL' order accounts for the correct boundary conditions for the N 3 LL resummation, for which the only unknown ingredients are higher-order anomalous dimensions. We use scale variations in a factorization theorem in both rapidity and virtuality space to estimate the perturbative uncertainties, accounting for both higher fixed-order corrections as well as higher-order towers of jet-p T logarithms. This formalism also predicts the correlations in the theory uncertainty between the exclusive 0-jet and inclusive 1-jet bins. At the values of R used experimentally, there are important corrections due to jet algorithm clustering that include logarithms of R. Although we do not sum logarithms of R, we do include an explicit contribution in our uncertainty estimate to account for higher-order jet clustering logarithms. Precision predictions for this H+0-jet cross section and its theoretical uncertainty are an integral part of Higgs analyses that employ jet binning.

  11. Jet p{sub T} resummation in Higgs production at NNLL'+NNLO

    Energy Technology Data Exchange (ETDEWEB)

    Stewart, Iain W. [Massachusetts Institute of Technology, Cambridge, MA (United States). Center for Theoretical Physics; Tackmann, Frank J. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany). Gruppe Theorie; Walsh, Jonathan R.; Zuberi, Saba [California Univ., Berkeley, CA (United States). Ernes Orlando Lawrence Berkeley National Laboratory

    2013-07-15

    We present predictions for Higgs production via gluon fusion with a p{sub T} veto on jets and with the resummation of jet-veto logarithms at NNLL'+NNLO order. These results incorporate explicit O({alpha}{sub s}{sup 2}) calculations of soft and beam functions, which include the dominant dependence on the jet radius R. In particular the NNLL' order accounts for the correct boundary conditions for the N{sup 3}LL resummation, for which the only unknown ingredients are higher-order anomalous dimensions. We use scale variations in a factorization theorem in both rapidity and virtuality space to estimate the perturbative uncertainties, accounting for both higher fixed-order corrections as well as higher-order towers of jet-p{sub T} logarithms. This formalism also predicts the correlations in the theory uncertainty between the exclusive 0-jet and inclusive 1-jet bins. At the values of R used experimentally, there are important corrections due to jet algorithm clustering that include logarithms of R. Although we do not sum logarithms of R, we do include an explicit contribution in our uncertainty estimate to account for higher-order jet clustering logarithms. Precision predictions for this H+0-jet cross section and its theoretical uncertainty are an integral part of Higgs analyses that employ jet binning.

  12. Buoyancy Effects in Turbulent Jet Flames in Crossflow

    Science.gov (United States)

    Boxx, Isaac; Idicheria, Cherian; Clemens, Noel

    2003-11-01

    The aim of this study is to investigate the effects of buoyancy on the structure of turbulent, non-premixed hydrocarbon jet-flames in crossflow (JFICF). This was accomplished using a small jet-in-crossflow facility which can be oriented at a variety of angles with respect to the gravity vector. This facility enables us to alter the relative influence of buoyancy on the JFICF without altering the jet-exit Reynolds number, momentum flux ratio or the geometry of the system. Results are compared to similar, but non-buoyant, JFICF studied in microgravity. Departures of jet-centerline trajectory from the well-known power-law scaling of turbulent JFICF were used to explore the transition from a buoyancy-influenced regime to a momentum dominated one. The primary diagnostic was CCD imaging of soot-luminosity. We present results on ethylene jet flames with jet-exit Reynolds numbers of 1770 to 8000 and momentum flux ratios of 5 to 13.

  13. Jet formation in shock-heavy gas bubble interaction

    Institute of Scientific and Technical Information of China (English)

    Zhi-Gang Zhai; Ting Si; Li-Yong Zou; Xi-Sheng Luo

    2013-01-01

    The influences of the acoustic impedance and shock strength on the jet formation in shock-heavy gas bubble interaction are numerically studied in this work.The process of a shock interacting with a krypton or a SF6 bubble is studied by the numerical method VAS2D.As a validation,the experiments of a SF6 bubble accelerated by a planar shock were performed.The results indicate that,due to the mismatch of acoustic impedance,the way of jet formation in heavy gas bubble with different species is diversified under the same initial condition.With respect to the same bubble,the manner of jet formation is also distinctly different under different shock strengths.The disparities of the acoustic impedance result in different effects of shock focusing in the bubble,and different behaviors of shock wave inside and outside the bubble.The analyses of the wave pattern and the pressure variation indicate that the jet formation is closely associated with the pressure perturbation.Moreover,the analysis of the vorticity deposition,and comparisons of circulation and baroclinic torque show that the baroclinic vorticity also contributes to the jet formation.It is concluded that the pressure perturbation and baroclinic vorticity deposition are the two dominant factors for the jet formation in shock-heavy gas bubble interaction.

  14. DeepJet: a deep-learned multiclass jet-tagger for slim and fat jets

    CERN Multimedia

    CERN. Geneva; Qu, Huilin; Stoye, Markus; Kieseler, Jan; Verzetti, Mauro

    2018-01-01

    We present a customized neural network architecture for both, slim and fat jet tagging. It is based on the idea to keep the concept of physics objects, like particle flow particles, as a core element of the network architecture. The deep learning algorithm works for most of the common jet classes, i.e. b, c, usd and gluon jets for slim jets and W, Z, H, QCD and top classes for fat jets. The developed architecture promising gains in performance as shown in simulation of the CMS collaboration. Currently the tagger is under test in real data in the CMS experiment.

  15. The dominance of norm

    Directory of Open Access Journals (Sweden)

    Edward L. Rubin

    2017-06-01

    Full Text Available Objective to revisit the debate about rational choice theory from the legal cultural and historical perspectives. Methods dialectic approach to the cognition of social phenomena allowing to analyze them in their historical development and functioning in the context of the integrity of subjective and objective factors this determines the choice of the research methods systemicstructural formallegal and comparative. Results The first part of this chapter will explain the way in which people in societies different from our own were subject to other motivations in situations where selfinterest would tend to dominate in our society. The reasoning is based on three examples one drawn from the history of Ancient Rome one from the High Middle Ages of the European society and one from a contemporary nonWestern culture. The second part of the chapter analyzes the reason why material selfinterest maximizing became a dominant motivation in the modern Western society. The works on historical sociology attribute this development to Calvinism but this hypothesis suffers from some serious defects. In the article we prove that the modern sensibility resulted from much longeracting trends specifically secularization urbanization and commercialization. The final section of the chapter explores the relationship between the Westrsquos prevailing norm of selfinterest maximization and the particular norms that have been discussed in microeconomic theory. It argues that some of these norms are internal to the prevailing one and are thus explicable in terms of material selfinterest but that others reflect additional norms in the general society that exist alongside and sometimes in competition with the prevailing norm of selfinterest maximization. The historicallybased view that selfinterest maximizing is a prevailing norm rather than a human universal allows these other norms to be acknowledged in a plausible and realistic manner rather than being explained away by a

  16. Jet production and the dynamical role of color

    International Nuclear Information System (INIS)

    Brodsky, S.J.

    1977-05-01

    It is discussed how multiparticle jets which originate from quarks, multiquarks, hadrons, or gluons can be distinguished by their quantum number retention, leading particle distributions, and hadronic multiplicity. The possible quantitative connection between initial color separation and hadron multiplicity is emphasized. Evidence for wee quark exchange as a dominant hadronic mechanism is presented. Also discussed are several new mechanisms for gluon jet production. Finally, the possibility of utilizing a high multiplicity trigger to expose gluon exchange and production contributions in hadron- and lepton-induced reactions are considered

  17. Properties of large p sub( t) jets in massive lepton-pair production at large q sub( t)

    International Nuclear Information System (INIS)

    Kinoshita, Kisei; Kinoshita, Yukiko.

    1979-01-01

    Production mechanism of massive lepton-pairs with large transverse momentum is discussed in connection with the properties of hadronic jets on the away side. Significant differences of CIM and QCD perturbation model will show up in the angular dependence and quantum number content of the away jets. If the QCD perturbation terms dominate, we can extract the gluon distributions inside hadrons and the gluon fragmentation function from the properties of the away jets triggering large q sub( t) lepton pairs. (author)

  18. Jet photoproduction at HERA

    International Nuclear Information System (INIS)

    Frixione, S.

    1997-01-01

    We compute various kinematical distributions for one-jet and two-jet inclusive photoproduction at HERA. Our results are accurate to next-to-leading order in QCD. We use the subtraction method for the cancellation of infrared singularities. We perform a thorough study of the reliability of QCD predictions; in particular, we consider the scale dependence of our results and discuss the cases when the perturbative expansion might break down. We also deal with the problem of the experimental definition of the pointlike and hadronic components of the incident photon, and briefly discuss the sensitivity of QCD predictions upon the input parameters of the calculation, like α S and the parton densities. (orig.)

  19. QCD and jets

    International Nuclear Information System (INIS)

    Munehisa, Tomo

    1990-01-01

    We present a review on the parton shower in e + e - annihilation. Also we discuss the next-to-leading-logarithmic parton shower. We emphasize that this new model provides a useful tool for the determinations of Λ MS from jet distributions. Analysis by the new model gives us Λ MS = 0.235±0.052 GeV from data of PETRA, PEP and TRISTAN. (author)

  20. Active control of continuous air jet with bifurcated synthetic jets

    Directory of Open Access Journals (Sweden)

    Dančová Petra

    2017-01-01

    Full Text Available The synthetic jets (SJs have many significant applications and the number of applications is increasing all the time. In this research the main focus is on the primary flow control which can be used effectively for the heat transfer increasing. This paper deals with the experimental research of the effect of two SJs worked in the bifurcated mode used for control of an axisymmetric air jet. First, the control synthetic jets were measured alone. After an adjustment, the primary axisymmetric jet was added in to the system. For comparison, the primary flow without synthetic jets control was also measured. All experiments were performed using PIV method whereby the synchronization between synthetic jets and PIV system was necessary to do.

  1. Jet-hadron correlations relative to the event plane in Pb--Pb collisions at the LHC in ALICE

    CERN Document Server

    Mazer, Joel

    In relativistic heavy ion collisions at the Large Hadron Collider (LHC), a hot, dense and strongly interacting medium known as the Quark Gluon Plasma (QGP) is produced. Quarks and gluons from incoming nuclei collide to produce partons at high momenta early in the collisions. By fragmenting into collimated sprays of hadrons, these partons form 'jets'. Within the framework of perturbative Quantum Chromodynamics (pQCD), jet production is well understood in pp collisions. We can use jets measured in pp interactions as a baseline reference for comparing to heavy ion collision systems to detect and study jet quenching. The jet quenching mechanism can be studied through the angular correlations of trigger jets with charged hadrons and is examined in transverse momentum bins of the trigger jets, transverse momentum bins of the associated hadrons, and studied as a function of collision centrality. A highly robust and precise background subtraction method is used in this analysis to remove the complex, flow domin...

  2. Jet operated heat pump

    International Nuclear Information System (INIS)

    Collard, T.H.

    1982-01-01

    A jet pump system is shown that utilizes waste heat to provide heating and/or cooling. Waste heat diverted through a boiler causes a refrigerant to evaporate and expand for supersonic discharge through a nozzle thereby creating a vacuum in an evaporator coil. The vacuum draws the refrigerant in a gaseous state into a condensing section of a jet pump along with refrigerant from a reservoir in a subcooled liquid form. This causes condensation of the gas in a condensation section of the jet pump, while moving at constant velocity. The change in momentum of the fluid overcomes the system high side pressure. Some of the condensate is cooled by a subcooler. Refrigerant in a subcooled liquid state from the subcooler is fed back into the evaporator and the condensing section with an adequate supply being insured by the reservoir. The motive portion of the condensate is returned to the boiler sans subcooling. By proper valving start-up is insured, as well as the ability to switch from heating to cooling

  3. Greenland plateau jets

    Directory of Open Access Journals (Sweden)

    George William Kent Moore

    2013-08-01

    Full Text Available The high ice-covered topography of Greenland represents a significant barrier to atmospheric flow and, as a direct and indirect result, it plays a crucial role in the coupled climate system. The wind field over Greenland is important in diagnosing regional weather and climate, thereby providing information on the mass balance of the ice sheet as well as assisting in the interpretation of ice core data. Here, we identify a number of hitherto unrecognised features of the three-dimensional wind field over Greenland; including a 2500-km-long jet along the central ice sheet's western margin that extends from the surface into the middle-troposphere, as well as a similar but smaller scale and less intense feature along its eastern margin. We refer to these features as Greenland Plateau Jets. The jets are coupled to the downslope katabatic flow and we argue that they are maintained by the zonal temperature gradients associated with the strong temperature inversion over the central ice sheet. Their importance for Greenland's regional climate is discussed.

  4. Jet-hadron correlations relative to the event plane at the LHC with ALICE

    Science.gov (United States)

    Mazer, Joel; Alice Collaboration

    2017-11-01

    In ultra relativistic heavy-ion collisions at the Large Hadron Collider (LHC), conditions are met to produce a hot, dense and strongly interacting medium known as the Quark Gluon Plasma (QGP). Quarks and gluons from incoming nuclei collide to produce partons at high momenta early in the collisions. By fragmenting into collimated sprays of hadrons, these partons form 'jets'. The outgoing partons scatter and interact with the medium, leading to a manifestation of medium modifications of jets in the final state, known as jet quenching. Within the framework of perturbative QCD, jet production is well understood in pp collisions. We use jets measured in pp interactions as a baseline reference for comparing to heavy-ion collision systems to detect and study jet quenching. The jet quenching mechanism can be studied through the angular correlations of jets with charged hadrons and is examined in transverse momentum (pT) bins of the jets, pT bins of the associated hadrons, and as a function of collision centrality. A robust and precise background subtraction method is used in this analysis to remove the complex, flow dominated, heavy-ion background. The analysis of angular correlations for different orientations of the jet relative to the event plane allows for the study of the path-length dependence of medium modifications to jets. The event plane dependence of azimuthal angular correlations of charged hadrons with respect to the axis of an R = 0.2 reconstructed full (charged + neutral) jet in Pb-Pb collisions at √{sNN} = 2.76 TeV in ALICE is presented. Results are compared for three angular bins of the jet relative to the event plane in mid-peripheral events. The yields relative to the event plane are presented and then quantified through yield ratio calculations. The results show no significant path-length dependence on the medium modifications.

  5. γ-jets physics with the EMCal calorimeter in ALICE experiment at LHC

    International Nuclear Information System (INIS)

    Bourdaud, G.

    2008-11-01

    Heavy ion collisions at LHC will produce a new state of matter: the quark-gluon plasma (QGP). Photons are not sensible to the strong interaction which dominates the nuclear medium, and hence are a valuable tool to explore QGP. Gamma-jets are rare hard processes: a photon and a parton are emitted back-to-back. The parton hadronises and produces a jet of particles. These jets are quenched due to the strong interaction of the parton with the QGP. This quenching, or more precisely the re-distribution of the energy in the jet, can be measured by the modification of the distribution of the particle energy in the jet, comparing p-p and Pb-Pb collisions (fragmentation functions or hump-backed plateau distributions). For this purpose, jet energy is needed, and can be provided precisely by gamma-jet measurement. Our goal is to use EMCal to detect a photon correlated with a jet reconstructed in ALICE tracking system. Then, the jet energy distribution are compared for p-p an Pb-Pb collisions. Gamma-jet physics is first addressed, the particle identification with EMCal is introduced to isolate the direct photon, i.e. a photon and a jet emitted back-to-back. Methods of jet identification and reconstruction are developed to determine hump-backed plateau distributions. Finally, these methods are tested to evaluate ALICE and particularly EMCal capabilities for gamma-jet study at LHC and to quantify the sensibility of this probe to explore the QGP. (author)

  6. Multiple Jets at the LHC with High Energy Jets

    DEFF Research Database (Denmark)

    Andersen, Jeppe Rosenkrantz; Smillie, Jennifer M.

    2011-01-01

    We present a flexible Monte Carlo implementation of the perturbative framework of High Energy Jets, describing multi-jet events at hadron colliders. The description includes a resummation which ensures leading logarithmic accuracy for large invariant mass between jets, and is matched to tree......-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...

  7. Experiment and simulation study of laser dicing silicon with water-jet

    Energy Technology Data Exchange (ETDEWEB)

    Bao, Jiading; Long, Yuhong, E-mail: longyuhong@guet.edu.cn; Tong, Youqun; Yang, Xiaoqing; Zhang, Bin; Zhou, Zupeng

    2016-11-30

    Highlights: • The explosive melt expulsion could be a dominant process for the laser ablating silicon in liquids with ns-pulsed laser of 1064 nm irradiating. • Self-focusing phenomenon was found and its causes are analyzed. • SPH modeling technique was employed to understand the effect of water and water-jet on debris removal during water-jet laser machining. - Abstract: Water-jet laser processing is an internationally advanced technique, which combines the advantages of laser processing with water jet cutting. In the study, the experiment of water-jet laser dicing are conducted with ns pulsed laser of 1064 nm irradiating, and Smooth Particle Hydrodynamic (SPH) technique by AUTODYN software was modeled to research the fluid dynamics of water and melt when water jet impacting molten material. The silicon surface morphology of the irradiated spots has an appearance as one can see in porous formation. The surface morphology exhibits a large number of cavities which indicates as bubble nucleation sites. The observed surface morphology shows that the explosive melt expulsion could be a dominant process for the laser ablating silicon in liquids with nanosecond pulse laser of 1064 nm irradiating. Self-focusing phenomenon was found and its causes are analyzed. Smooth Particle Hydrodynamic (SPH) modeling technique was employed to understand the effect of water and water-jet on debris removal during water-jet laser machining.

  8. Perfect secure domination in graphs

    Directory of Open Access Journals (Sweden)

    S.V. Divya Rashmi

    2017-07-01

    Full Text Available Let $G=(V,E$ be a graph. A subset $S$ of $V$ is a dominating set of $G$ if every vertex in $Vsetminus  S$ is adjacent to a vertex in $S.$ A dominating set $S$ is called a secure dominating set if for each $vin Vsetminus S$ there exists $uin S$ such that $v$ is adjacent to $u$ and $S_1=(Ssetminus{u}cup {v}$ is a dominating set. If further the vertex $uin S$ is unique, then $S$ is called a perfect secure dominating set. The minimum cardinality of a perfect secure dominating set of $G$ is called the perfect  secure domination number of $G$ and is denoted by $gamma_{ps}(G.$ In this paper we initiate a study of this parameter and present several basic results.

  9. Dominant optic atrophy

    Directory of Open Access Journals (Sweden)

    Lenaers Guy

    2012-07-01

    Full Text Available Abstract Definition of the disease Dominant Optic Atrophy (DOA is a neuro-ophthalmic condition characterized by a bilateral degeneration of the optic nerves, causing insidious visual loss, typically starting during the first decade of life. The disease affects primary the retinal ganglion cells (RGC and their axons forming the optic nerve, which transfer the visual information from the photoreceptors to the lateral geniculus in the brain. Epidemiology The prevalence of the disease varies from 1/10000 in Denmark due to a founder effect, to 1/30000 in the rest of the world. Clinical description DOA patients usually suffer of moderate visual loss, associated with central or paracentral visual field deficits and color vision defects. The severity of the disease is highly variable, the visual acuity ranging from normal to legal blindness. The ophthalmic examination discloses on fundoscopy isolated optic disc pallor or atrophy, related to the RGC death. About 20% of DOA patients harbour extraocular multi-systemic features, including neurosensory hearing loss, or less commonly chronic progressive external ophthalmoplegia, myopathy, peripheral neuropathy, multiple sclerosis-like illness, spastic paraplegia or cataracts. Aetiology Two genes (OPA1, OPA3 encoding inner mitochondrial membrane proteins and three loci (OPA4, OPA5, OPA8 are currently known for DOA. Additional loci and genes (OPA2, OPA6 and OPA7 are responsible for X-linked or recessive optic atrophy. All OPA genes yet identified encode mitochondrial proteins embedded in the inner membrane and ubiquitously expressed, as are the proteins mutated in the Leber Hereditary Optic Neuropathy. OPA1 mutations affect mitochondrial fusion, energy metabolism, control of apoptosis, calcium clearance and maintenance of mitochondrial genome integrity. OPA3 mutations only affect the energy metabolism and the control of apoptosis. Diagnosis Patients are usually diagnosed during their early childhood, because of

  10. Jet target intense neutron source

    International Nuclear Information System (INIS)

    Meier, K.L.

    1977-01-01

    A jet target Intense Neutron Source (INS) is being built by the Los Alamos Scientific Laboratory with DOE/MFE funding in order to perform radiation damage experiments on materials to be used in fusion power reactors. The jet target can be either a supersonic or a subsonic jet. Each type has its particular advantages and disadvantages, and either of the jets can be placed inside the spherical blanket converter which will be used to simulate a fusion reactor neutron environment. Preliminary mock-up experiments with a 16-mA, 115 keV, H + ion beam on a nitrogen gas supersonic jet show no serious problems in the beam formation, transport, or jet interaction

  11. Identifying jet quantum numbers event by event

    International Nuclear Information System (INIS)

    Teper, M.J.

    1979-12-01

    A method is proposed to identify the parton that gives rise to any particular jet. The method improves with the number of particles in the jet, and should indicate which of the jets in a three jet event at PETRA is the gluon jet. (author)

  12. Total Domination Versus Paired-Domination in Regular Graphs

    Directory of Open Access Journals (Sweden)

    Cyman Joanna

    2018-05-01

    Full Text Available A subset S of vertices of a graph G is a dominating set of G if every vertex not in S has a neighbor in S, while S is a total dominating set of G if every vertex has a neighbor in S. If S is a dominating set with the additional property that the subgraph induced by S contains a perfect matching, then S is a paired-dominating set. The domination number, denoted γ(G, is the minimum cardinality of a dominating set of G, while the minimum cardinalities of a total dominating set and paired-dominating set are the total domination number, γt(G, and the paired-domination number, γpr(G, respectively. For k ≥ 2, let G be a connected k-regular graph. It is known [Schaudt, Total domination versus paired domination, Discuss. Math. Graph Theory 32 (2012 435–447] that γpr(G/γt(G ≤ (2k/(k+1. In the special case when k = 2, we observe that γpr(G/γt(G ≤ 4/3, with equality if and only if G ≅ C5. When k = 3, we show that γpr(G/γt(G ≤ 3/2, with equality if and only if G is the Petersen graph. More generally for k ≥ 2, if G has girth at least 5 and satisfies γpr(G/γt(G = (2k/(k + 1, then we show that G is a diameter-2 Moore graph. As a consequence of this result, we prove that for k ≥ 2 and k ≠ 57, if G has girth at least 5, then γpr(G/γt(G ≤ (2k/(k +1, with equality if and only if k = 2 and G ≅ C5 or k = 3 and G is the Petersen graph.

  13. PARSEC-SCALE FARADAY ROTATION MEASURES FROM GENERAL RELATIVISTIC MAGNETOHYDRODYNAMIC SIMULATIONS OF ACTIVE GALACTIC NUCLEUS JETS

    International Nuclear Information System (INIS)

    Broderick, Avery E.; McKinney, Jonathan C.

    2010-01-01

    It is now possible to compare global three-dimensional general relativistic magnetohydrodynamic (GRMHD) jet formation simulations directly to multi-wavelength polarized VLBI observations of the pc-scale structure of active galactic nucleus (AGN) jets. Unlike the jet emission, which requires post hoc modeling of the nonthermal electrons, the Faraday rotation measures (RMs) depend primarily upon simulated quantities and thus provide a direct way to confront simulations with observations. We compute RM distributions of a three-dimensional global GRMHD jet formation simulation, extrapolated in a self-consistent manner to ∼10 pc scales, and explore the dependence upon model and observational parameters, emphasizing the signatures of structures generic to the theory of MHD jets. With typical parameters, we find that it is possible to reproduce the observed magnitudes and many of the structures found in AGN jet RMs, including the presence of transverse RM gradients. In our simulations, the RMs are generated in the circum-jet material, hydrodynamically a smooth extension of the jet itself, containing ordered toroidally dominated magnetic fields. This results in a particular bilateral morphology that is unlikely to arise due to Faraday rotation in distant foreground clouds. However, critical to efforts to probe the Faraday screen will be resolving the transverse jet structure. Therefore, the RMs of radio cores may not be reliable indicators of the properties of the rotating medium. Finally, we are able to constrain the particle content of the jet, finding that at pc scales AGN jets are electromagnetically dominated, with roughly 2% of the comoving energy in nonthermal leptons and much less in baryons.

  14. PARSEC-SCALE FARADAY ROTATION MEASURES FROM GENERAL RELATIVISTIC MAGNETOHYDRODYNAMIC SIMULATIONS OF ACTIVE GALACTIC NUCLEUS JETS

    Energy Technology Data Exchange (ETDEWEB)

    Broderick, Avery E [Canadian Institute for Theoretical Astrophysics, 60 St. George St., Toronto, ON M5S 3H8 (Canada); McKinney, Jonathan C., E-mail: aeb@cita.utoronto.c, E-mail: jmckinne@stanford.ed [Department of Physics and Kavli Institute for Particle Astrophysics and Cosmology, Stanford University, Stanford, CA 94305-4060 (United States)

    2010-12-10

    It is now possible to compare global three-dimensional general relativistic magnetohydrodynamic (GRMHD) jet formation simulations directly to multi-wavelength polarized VLBI observations of the pc-scale structure of active galactic nucleus (AGN) jets. Unlike the jet emission, which requires post hoc modeling of the nonthermal electrons, the Faraday rotation measures (RMs) depend primarily upon simulated quantities and thus provide a direct way to confront simulations with observations. We compute RM distributions of a three-dimensional global GRMHD jet formation simulation, extrapolated in a self-consistent manner to {approx}10 pc scales, and explore the dependence upon model and observational parameters, emphasizing the signatures of structures generic to the theory of MHD jets. With typical parameters, we find that it is possible to reproduce the observed magnitudes and many of the structures found in AGN jet RMs, including the presence of transverse RM gradients. In our simulations, the RMs are generated in the circum-jet material, hydrodynamically a smooth extension of the jet itself, containing ordered toroidally dominated magnetic fields. This results in a particular bilateral morphology that is unlikely to arise due to Faraday rotation in distant foreground clouds. However, critical to efforts to probe the Faraday screen will be resolving the transverse jet structure. Therefore, the RMs of radio cores may not be reliable indicators of the properties of the rotating medium. Finally, we are able to constrain the particle content of the jet, finding that at pc scales AGN jets are electromagnetically dominated, with roughly 2% of the comoving energy in nonthermal leptons and much less in baryons.

  15. Dynamics of Newtonian annular jets

    International Nuclear Information System (INIS)

    Paul, D.D.

    1978-12-01

    The main objectives of this investigation are to identify the significant parameters affecting the dynamics of Newtonian annular jets, and to develop theoretical models for jet break-up and collapse. This study has been motivated by recent developments in laser-fusion reactor designs; one proposed cavity design involves the use of an annular lithium jet to protect the cavity wall from the pellet debris emanating from the microexplosion

  16. Di-Jet Production in Photon-Photon colisions at $\\sqrt{s_{ee}}$ from 189 to 209 GeV

    CERN Document Server

    Abbiendi, G; Åkesson, P F; Alexander, Gideon; Allison, J; Amaral, P; Anagnostou, G; Anderson, K J; Arcelli, S; Asai, S; Axen, D A; Azuelos, Georges; Bailey, I; Barberio, E; Barlow, R J; Batley, J Richard; Bechtle, P; Behnke, T; Bell, K W; Bell, P J; Bella, G; Bellerive, A; Benelli, G; Bethke, Siegfried; Biebel, O; Bloodworth, Ian J; Boeriu, O; Bock, P; Bonacorsi, D; Boutemeur, M; Braibant, S; Brigliadori, L; Brown, R M; Büsser, K; Burckhart, H J; Campana, S; Carnegie, R K; Caron, B; Carter, A A; Carter, J R; Chang, C Y; Charlton, D G; Csilling, Akos; Cuffiani, M; Dado, S; Dallison, S; de Roeck, A; De Wolf, E A; Desch, Klaus; Dienes, B; Donkers, M; Dubbert, J; Duchovni, E; Duckeck, G; Duerdoth, I P; Elfgren, E; Etzion, E; Fabbri, Franco Luigi; Feld, L; Ferrari, P; Fiedler, F; Fleck, I; Ford, M; Frey, A; Fürtjes, A; Gagnon, P; Gary, J W; Gaycken, G; Geich-Gimbel, C; Giacomelli, G; Giacomelli, P; Giunta, M; Goldberg, J; Gross, E; Grunhaus, Jacob; Gruwé, M; Günther, P O; Sen-Gupta, A; Hajdu, C; Hamann, M; Hanson, G G; Harder, K; Harel, A; Harin-Dirac, M; Hauschild, M; Hauschildt, J; Hawkes, C M; Hawkings, R; Hemingway, Richard J; Hensel, C; Herten, G; Heuer, R D; Hill, J C; Hoffman, K; Homer, R James; Horváth, D; Howard, R; Igo-Kemenes, P; Ishii, K; Jeremie, H; Jovanovic, P; Junk, T R; Kanaya, N; Kanzaki, J; Karapetian, G V; Karlen, D A; Kartvelishvili, V G; Kawagoe, K; Kawamoto, T; Keeler, Richard K; Kellogg, R G; Kennedy, B W; Kim, D H; Klein, K; Klier, A; Kluth, S; Kobayashi, T; Kobel, M; Komamiya, S; Kormos, L L; Krämer, T; Kress, T; Krieger, P; Von Krogh, J; Krop, D; Krüger, K; Kühl, T; Kupper, M; Lafferty, G D; Landsman, Hagar Yaël; Lanske, D; Layter, J G; Leins, A; Lellouch, D; Letts, J; Levinson, L; Lillich, J; Lloyd, S L; Loebinger, F K; Lü, J; Ludwig, J; MacPherson, A; Mader, W; Marcellini, S; Marchant, T E; Martin, A J; Martin, J P; Masetti, G; Mashimo, T; Mättig, P; McDonald, W J; McKenna, J A; McMahon, T J; McPherson, R A; Meijers, F; Méndez-Lorenzo, P; Menges, W; Merritt, F S; Mes, H; Michelini, Aldo; Mihara, S; Mikenberg, G; Miller, D J; Moed, S; Mohr, W; Mori, T; Mutter, A; Nagai, K; Nakamura, I; Neal, H A; Nisius, R; O'Neale, S W; Oh, A; Okpara, A N; Oreglia, M J; Orito, S; Pahl, C; Pásztor, G; Pater, J R; Patrick, G N; Pilcher, J E; Pinfold, James L; Plane, D E; Poli, B; Polok, J; Pooth, O; Przybycien, M B; Quadt, A; Rabbertz, K; Rembser, C; Renkel, P; Rick, Hartmut; Roney, J M; Rosati, S; Rozen, Y; Runge, K; Sachs, K; Saeki, T; Sahr, O; Sarkisyan-Grinbaum, E; Schaile, A D; Schaile, O; Scharff-Hansen, P; Schieck, J; Schörner-Sadenius, T; Schröder, M; Schumacher, M; Schwick, C; Scott, W G; Seuster, R; Shears, T G; Shen, B C; Sherwood, P; Siroli, G P; Skuja, A; Smith, A M; Sobie, R J; Söldner-Rembold, S; Spanó, F; Stahl, A; Stephens, K; Strom, D; Ströhmer, R; Tarem, S; Tasevsky, M; Taylor, R J; Teuscher, R; Thomson, M A; Torrence, E; Toya, D; Tran, P; Trefzger, T M; Tricoli, A; Trigger, I; Trócsányi, Z L; Tsur, E; Turner-Watson, M F; Ueda, I; Ujvári, B; Vachon, B; Vollmer, C F; Vannerem, P; Verzocchi, M; Voss, H; Vossebeld, Joost Herman; Waller, D; Ward, C P; Ward, D R; Watkins, P M; Watson, A T; Watson, N K; Wells, P S; Wengler, T; Wermes, N; Wetterling, D; Wilson, G W; Wilson, J A; Wolf, G; Wyatt, T R; Yamashita, S; Zer-Zion, D; Zivkovic, L

    2003-01-01

    Di-jet producion is studied in collisions of quasi-real photons at e+e- centre- of-mass energies sqrt(s)ee from 189 to 209 GeV at LEP. The data were collected with the OPAL detector. Jets are reconstructed using an inclusive k_t clustering algorithm for all cross-section measurements presented. A cone jet algorithm is used in addition to study the different structure of the jets resulting from either of the algorithms. The inclusive di-jet cross-section is measured as a function of the mean transverse energy Etm(jet) of the two leading jets, and as a functiuon of the estimated fraction of the photon momentum carried by the parton entering the hard sub-process, xg, for different regions of Etm (jet). Angular distribution in di-jet events are measured and used to demonstrate the dominance of quark and gluon initiated processes in different regions of phase space. Furthermore the inclusive di-jet cross-section as a function of |eta(jet)| and |delta eta (jet)| is presented where eta(jet) is the jet pseudo-rapidit...

  17. Photon + jets at D0

    Energy Technology Data Exchange (ETDEWEB)

    Sonnenschein, Lars; /RWTH Aachen U.

    2009-06-01

    Photon plus jet production has been studied by the D0 experiment in Run II of the Fermilab Tevatron Collider at a centre of mass energy of {radical}s = 1.96 TeV. Measurements of the inclusive photon, inclusive photon plus jet, photon plus heavy flavour jet cross sections and double parton interactions in photon plus three jet events are presented. They are based on integrated luminosities between 0.4 fb{sup -1} and 1.0 fb{sup -1}. The results are compared to perturbative QCD calculations in various approximations.

  18. SIGNATURES OF RELATIVISTIC HELICAL MOTION IN THE ROTATION MEASURES OF ACTIVE GALACTIC NUCLEUS JETS

    Energy Technology Data Exchange (ETDEWEB)

    Broderick, Avery E [Canadian Institute for Theoretical Astrophysics, 60 St. George Street, Toronto, ON M5S 3H8 (Canada); Loeb, Abraham [Institute for Theory and Computation, Harvard University, Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States)

    2009-10-01

    Polarization has proven to be an invaluable tool for probing magnetic fields in relativistic jets. Maps of the intrinsic polarization vectors have provided the best evidence to date for uniform, toroidally dominated magnetic fields within jets. More recently, maps of the rotation measure (RM) in jets have for the first time probed the field geometry of the cool, moderately relativistic surrounding material. In most cases, clear signatures of the toroidal magnetic field are detected, corresponding to gradients in RM profiles transverse to the jet. However, in many objects, these profiles also display marked asymmetries that are difficult to explain in simple helical jet models. Furthermore, in some cases, the RM profiles are strongly frequency and/or time dependent. Here we show that these features may be naturally accounted for by including relativistic helical motion in the jet model. In particular, we are able to reproduce bent RM profiles observed in a variety of jets, frequency-dependent RM profile morphologies, and even the time dependence of the RM profiles of knots in 3C 273. Finally, we predict that some sources may show reversals in their RM profiles at sufficiently high frequencies, depending upon the ratio of the components of jet sheath velocity transverse and parallel to the jet. Thus, multi-frequency RM maps promise a novel way in which to probe the velocity structure of relativistic outflows.

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

    NARCIS (Netherlands)

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

  20. 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

  1. Geometrical scaling of jet fragmentation photons

    Energy Technology Data Exchange (ETDEWEB)

    Hattori, Koichi, E-mail: koichi.hattori@riken.jp [RIKEN BNL Research Center, Brookhaven National Laboratory, Upton NY 11973 (United States); Theoretical Research Division, Nishina Center, RIKEN, Wako, Saitama 351-0198 (Japan); McLerran, Larry, E-mail: mclerran@bnl.gov [RIKEN BNL Research Center, Brookhaven National Laboratory, Upton NY 11973 (United States); Physics Dept., Bdg. 510A, Brookhaven National Laboratory, Upton, NY-11973 (United States); Physics Dept., China Central Normal University, Wuhan (China); Schenke, Björn, E-mail: bschenke@bnl.gov [Physics Dept., Bdg. 510A, Brookhaven National Laboratory, Upton, NY-11973 (United States)

    2016-12-15

    We discuss jet fragmentation photons in ultrarelativistic heavy-ion collisions. We argue that, if the jet distribution satisfies geometrical scaling and an anisotropic spectrum, these properties are transferred to photons during the jet fragmentation.

  2. Transition in synthetic jets

    Czech Academy of Sciences Publication Activity Database

    Tesař, Václav; Kordík, Jozef

    2012-01-01

    Roč. 187, NOV 2012 (2012), s. 105-117 ISSN 0924-4247 R&D Projects: GA TA ČR(CZ) TA02020795; GA ČR(CZ) GPP101/12/P556; GA ČR(CZ) GCP101/11/J019 Institutional research plan: CEZ:AV0Z20760514 Keywords : turbulence * synthetic jet * transition * velocity spectra Subject RIV: BK - Fluid Dynamics Impact factor: 1.841, year: 2012 http://www. science direct.com/ science /article/pii/S0924424712005031

  3. Hadron jets in perspective

    International Nuclear Information System (INIS)

    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

  4. Jet physics at LEP

    International Nuclear Information System (INIS)

    Venus, W.

    1991-01-01

    The results of studies of the jet structure of hadronic Z 0 decays performed in the first year of Large Electron-Positron collider (LEP) operation are reviewed. The measurements of the quantum chromodynamics (QCD) coupling constant α s (M z )and the detection of the presence of the triple gluon vertex are summarized. After a brief review of the promising status of QCD in relation to even the very soft processes, the running of the coupling constants to high energy is considered in the context of grand unified theories. The necessity and importance of further theoretical work is stressed. (author)

  5. Numerical simulation of flow characteristics of lean jet to cross-flow in safety injection of reactor cooling system

    International Nuclear Information System (INIS)

    Wang Haijun; He Huining; Luo Yushan; Wang Weishu

    2011-01-01

    In the present work, a numerical simulation was performed to study the flow characteristics of lean jet to cross flow in a main tube in the safety injection of reactor cooling system. The influence scope and mixing characteristics of the confined lean jet in cross-flow were studied. It can be concluded that three basic flow regimes are marked, namely the attached lean jet, lift-off lean jet and impinging lean jet. The velocity ratio V R is the key factor in the flow state. The depth and region of jet to main flow are enhanced with the increase of the velocity ratio. The jet flow penetrates through the main flow with the increase of the velocity ratio. At higher velocity ratio, the jet flow strikes the main flow bottom and circumfluence happens in upriver of main flow. The vortex flow characteristics dominate the flow near region of jet to cross-flow and the mixture of jet to cross-flow. At different velocity ratio V R , the vortex grows from the same displacement, but the vortex type and the vortex is different. At higher velocity ratio, the vortex develops fleetly, wears off sharp and dies out sharp. The study is very important to the heat transfer experiments of cross-flow jet and thermal stress analysis in the designs of nuclear engineering. (authors)

  6. High-$p_T$ multi-jet final states at ATLAS and CMS

    CERN Document Server

    Lange, Clemens

    2016-01-01

    The increase of the centre-of-mass energy of the Large Hadron Collider (LHC) to 13 TeV has opened up a new energy regime. Final states including high-momentum multi-jet signatures often dominate beyond standard model phenomena, in particular decay products of new heavy particles. While the potential di-photon resonance currently receives a lot of attention, multi-jet final states pose strong constraints on what physics model an observation could actually be described with. In this presentation, the latest results of the ATLAS and CMS collaborations in high transverse momentum multi-jet final states are summarised. This includes searches for heavy resonances and new phenomena in the di-jet mass spectrum, di-jet angular distributions, and the sum of transverse momenta in different event topologies. Furthermore, results on leptoquark pair production will be shown. A particular focus is laid on the different background estimation methods.

  7. On the shock cell structure and noise of supersonic jets

    Science.gov (United States)

    Tam, C. K. W.; Jackson, J. A.

    1983-01-01

    A linear solution modeling the shock cell structure of an axisymmetric supersonic jet operated at off-design conditions is developed by the method of multiple-scales. The model solution takes into account the gradual spatial change of the mean flow in the downstream direction. Turbulence in the mixing layer of the jet has the tendency of smoothing out the sharp velocity and density gradients induced by the shocks. To simulate this effect, eddy viscosity terms are incorporated in the model. It is known that the interaction between the quasi-periodic shock cells and the downstream propagating large turbulence structures in the mixing layer of the jet is responsible for the generation of broadband shock associated noise. Experimentally, the dominant part of this noise has been found to originate from the part of the jet near the end of the potential core. Calculated shock cell spacing at the end of the jet core according to the present model is used to estimate the peak frequencies of the shock associated noise for a range of observation angles. Very favorable agreement with experimental measurements is found.

  8. Turbulent jet in confined counterflow

    Indian Academy of Sciences (India)

    framework for presenting the results of the flowfield and jet penetration length. ... A turbulent jet is a basic free shear flow and has received research attention (see, .... MBE76 identify this to be a transitional zone and for. √ .... higher return flow and also higher velocity from counterflow due to a narrower gap thus leading.

  9. Associated jet production at HERA

    CERN Document Server

    Bartels, Julius; de Roeck, A; Graudenz, Dirk; Wüsthoff, M

    1996-01-01

    We compare the BFKL prediction for the associated production of forward jets at HERA with fixed-order matrix element calculations taking into account the kinematical cuts imposed by experimental conditions. Comparison with H1 data of the 1993 run favours the BFKL prediction. As a further signal of BFKL dynamics, we propose to look for the azimuthal dependence of the forward jets.

  10. Consolidating NASA's Arc Jets

    Science.gov (United States)

    Balboni, John A.; Gokcen, Tahir; Hui, Frank C. L.; Graube, Peter; Morrissey, Patricia; Lewis, Ronald

    2015-01-01

    The paper describes the consolidation of NASA's high powered arc-jet testing at a single location. The existing plasma arc-jet wind tunnels located at the Johnson Space Center were relocated to Ames Research Center while maintaining NASA's technical capability to ground-test thermal protection system materials under simulated atmospheric entry convective heating. The testing conditions at JSC were reproduced and successfully demonstrated at ARC through close collaboration between the two centers. New equipment was installed at Ames to provide test gases of pure nitrogen mixed with pure oxygen, and for future nitrogen-carbon dioxide mixtures. A new control system was custom designed, installed and tested. Tests demonstrated the capability of the 10 MW constricted-segmented arc heater at Ames meets the requirements of the major customer, NASA's Orion program. Solutions from an advanced computational fluid dynamics code were used to aid in characterizing the properties of the plasma stream and the surface environment on the calorimeters in the supersonic flow stream produced by the arc heater.

  11. 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...

  12. Disruption prediction at JET

    International Nuclear Information System (INIS)

    Milani, F.

    1998-12-01

    The sudden loss of the plasma magnetic confinement, known as disruption, is one of the major issue in a nuclear fusion machine as JET (Joint European Torus). Disruptions pose very serious problems to the safety of the machine. The energy stored in the plasma is released to the machine structure in few milliseconds resulting in forces that at JET reach several Mega Newtons. The problem is even more severe in the nuclear fusion power station where the forces are in the order of one hundred Mega Newtons. The events that occur during a disruption are still not well understood even if some mechanisms that can lead to a disruption have been identified and can be used to predict them. Unfortunately it is always a combination of these events that generates a disruption and therefore it is not possible to use simple algorithms to predict it. This thesis analyses the possibility of using neural network algorithms to predict plasma disruptions in real time. This involves the determination of plasma parameters every few milliseconds. A plasma boundary reconstruction algorithm, XLOC, has been developed in collaboration with Dr. D. O'Brien and Dr. J. Ellis capable of determining the plasma wall/distance every 2 milliseconds. The XLOC output has been used to develop a multilayer perceptron network to determine plasma parameters as l i and q ψ with which a machine operational space has been experimentally defined. If the limits of this operational space are breached the disruption probability increases considerably. Another approach for prediction disruptions is to use neural network classification methods to define the JET operational space. Two methods have been studied. The first method uses a multilayer perceptron network with softmax activation function for the output layer. This method can be used for classifying the input patterns in various classes. In this case the plasma input patterns have been divided between disrupting and safe patterns, giving the possibility of

  13. Dominance Hierarchies in Young Children

    Science.gov (United States)

    Edelman, Murray S.; Omark, Donald R.

    1973-01-01

    This study uses the ethological approach of seeking species characteristics and phylogenetic continuities in an investigation of human behavior. Among primates a striking consistency is the presence of some form of dominance hierarchy in many species. The present study examines peer group dominance hierarchies as they are perceived by children in…

  14. On dominator colorings in graphs

    Indian Academy of Sciences (India)

    colors required for a dominator coloring of G is called the dominator .... Theorem 1.3 shows that the complete graph Kn is the only connected graph of order n ... Conversely, if a graph G satisfies condition (i) or (ii), it is easy to see that χd(G) =.

  15. Nucleosynthesis in Jets from Collapsars

    International Nuclear Information System (INIS)

    Fujimoto, Shin-ichiro; Nishimura, Nobuya; Hashimoto, Masa-aki

    2008-01-01

    We investigate nucleosynthesis inside magnetically driven jets ejected from collapsars, or rotating magnetized stars collapsing to a black hole, based on two-dimensional magnetohydrodynamic simulation of the collapsars during the core collapse. We follow the evolution of the abundances of about 4000 nuclides from the collapse phase to the ejection phase using a large nuclear reaction network. We find that the r-process successfully operates only in the energetic jets (>10 51 erg), so that U and Th are synthesized abundantly, even when the collapsars have a relatively small magnetic field (10 10 G) and a moderately rotating core before the collapse. The abundance patterns inside the jets are similar to that of the r-elements in the solar system. The higher energy jets have larger amounts of 56 Ni. Less energetic jets, which have small amounts of 56 Ni, could induce GRB without supernova, such as GRB060505 and GRB060614

  16. Magnetically driven jets and winds

    Science.gov (United States)

    Lovelace, R. V. E.; Berk, H. L.; Contopoulos, J.

    1991-01-01

    Four equations for the origin and propagation of nonrelativistic jets and winds are derived from the basic conservation laws of ideal MHD. The axial current density is negative in the vicinity of the axis and positive at larger radii; there is no net current because this is energetically favored. The magnetic field is essential for the jet solutions in that the zz-component of the magnetic stress acts, in opposition to gravity, to drive matter through the slow magnetosonic critical point. For a representative self-consistent disk/jet solution relevant to a protostellar system, the reaction of the accreted mass expelled in the jets is 0.1, the ratio of the power carried by the jets to the disk luminosity is 0.66, and the ratio of the boundary layer to disk luminosities is less than about 0.13. The star's rotation rate decreases with time even for rotation rates much less than the breakup rate.

  17. Performance Enhancement of a Vertical Tail Using Synthetic Jet Actuators

    Science.gov (United States)

    Rathay, Nicholas

    The performance enhancement of a vertical tail using an array of finite span synthetic jet actuators was investigated in wind tunnel experiments on 1/25th, 1/19th, and 1/9 th scale models. The models were sweptback, tapered, and instrumented with multiple synthetic jets placed upstream of the rudder hinge--line with the objective of controlling the separation that commenced over the rudder when it was deflected to high angles. By controlling the separation, the side force generated by the tail was augmented, which may allow for the size of the tail to be decreased. This would reduce the weight, drag, and corresponding fuel costs of an airplane. The synthetic jets augmented the side force coefficient by a maximum of 0.17 (34%). Furthermore, the performance of the vertical tail was dependent on jet strength. It was expected that the increase in side force would continue to grow as the momentum generation capabilities of the jets improved. A primary goal of the research was to determine the effect of multiple synthetic jet parameters on side force enhancement. Experiments were conducted with various jet orifice configurations, which indicated the following: the spacing between adjacent orifice edges and the orifices' aspect ratio were relatively unimportant; in terms of quantifying jet strength, the area--based (3--D) momentum coefficient of the jets was a more dominant parameter than the blowing ratio or the chord--based (2--D) momentum coefficient. Moreover, the most favorable spanwise location of control was, in general, found to be near the mid--span at lower rudder deflections and toward the inboard section of the model at larger deflections. The optimal chordwise location was hypothesized to be on the stabilizer as close as possible to the hinge--line. An investigation into the spanwise spacing of active jets demonstrated that, for some conditions, when the individual strength of the jets was held constant, larger jet spacing was more effective. Also, similar

  18. Numerical investigation on liquid sheets interaction characteristics of liquid-liquid coaxial swirling jets in bipropellant thruster

    International Nuclear Information System (INIS)

    Ding, Jia-Wei; Li, Guo-Xiu; Yu, Yu-Song

    2016-01-01

    Highlights: • A LES-VOF model is conducted to simulate atomization of coaxial swirling jets. • Structure and flow field of coaxial swirling jets are investigated. • Merging process occurs at the nozzle exit and generates additional perturbation. • The Rayleigh mode instability dominates the breakup of ligaments. - Abstract: Spray atomization process of a liquid-liquid coaxial swirl injector in bipropellant thruster has been investigated using volume of fluid (VOF) method coupled with large eddy simulation methodology. With fine grid resolution, detailed flow field of interacted liquid sheet has been captured and analyzed. For coaxial swirling jet, static pressure drop in the region between the liquid sheets makes two liquid sheets to approach each other and merge. A strong pressure, velocity and turbulent fluctuations are calculated near the contact position of two coaxial jets. Simulation results indicate that additional perturbations are generated due to strong radial and axial shear effects between coaxial jets. Observation of droplet formation process reveals that the Rayleigh mode instability dominates the breakup of the ligament. Droplet diameter and distribution have been investigated quantitatively. The mean diameter of the coaxial jets is between that of the inner and the outer jets. Compared with the individual swirling jets, wider size distributions of droplets are produced in the coaxial jets.

  19. The Study on the Physical Properties of Blazar Jets

    Science.gov (United States)

    Kang, S. J.

    2017-09-01

    Active galactic nuclei (AGNs) belong to a special class of active galaxies, and have violent active phenomena and intense physical processes in the nuclei. Blazar is a subclass of AGNs, and has a relativistic jet with a small jet viewing angle. Therefore, the boosting effect is very important, and almost all the observed radiation is dominated by the jet. The relativistic jet physics is not very clear yet, such as the jet formation, collimation, and matter content etc. The multi-waveband radiation of blazar is dominated by jet, which provides an ideal laboratory for studying the jet physics. The first chapter of this thesis introduces the recent progress of AGNs and blazars. We further introduce the jet model that commonly used in blazars in the second chapter. In the third chapter, we fit simultaneously (or quasi-simultaneously) the multi-waveband spectral energy distributions (SEDs) for a sample of low-synchrotron-peaked (LSP) blazars with the jet model and χ2 procedure, which takes into account different soft photon fields (broad line region or a molecular torus). We find that the SED fitting with an external soft photon from IR torus is systematically better than that from the broad line region (BLR) based on a χ2 test, which suggests that the γ-ray emitting region most possibly stays outside the BLR. The minimum electron Lorentz factor, γmin, is constrained from the modeling of these LSP blazars with good soft X-ray data, and in a range from 5 to 160 (with a median value of 55), which plays a key role in jet power estimation. Assuming one-to-one ratio of proton and electron, we find that the jet power for LSP blazars is systematically higher than that of Fanaroff-Riley type II (FR II) radio galaxies. A possible reason for this is that there are some positrons in the jets of these blazars. If this is the case, the jet power will be reduced. Therefore, we propose a mixed composition of e±-p in the jets of these LSP blazars. If we assume that the jet power

  20. Inclusive jet cross sections and jet shapes at CDF

    International Nuclear Information System (INIS)

    Wainer, N.

    1991-09-01

    The inclusive jet cross section and jet shapes at √s = 1.8 TeV have been measured by CDF at the Fermilab Tevatron Collider. results are compared to recent next-to-leading order QCD calculations, which predict variation of the cross section with cone size, as well as variation of the jet shape with energy. A lower limit on the parameter Λ c , which characterize a contact interaction associated with quark sub-structure is determined to be 1400 GeV at the 95% confidence level. 3 refs., 4 figs

  1. Domination criticality in product graphs

    Directory of Open Access Journals (Sweden)

    M.R. Chithra

    2015-07-01

    Full Text Available A connected dominating set is an important notion and has many applications in routing and management of networks. Graph products have turned out to be a good model of interconnection networks. This motivated us to study the Cartesian product of graphs G with connected domination number, γc(G=2,3 and characterize such graphs. Also, we characterize the k−γ-vertex (edge critical graphs and k−γc-vertex (edge critical graphs for k=2,3 where γ denotes the domination number of G. We also discuss the vertex criticality in grids.

  2. First experiments in JET

    International Nuclear Information System (INIS)

    Rebut, P.H.; Bartlett, D.V.; Baeumel, G.

    1985-01-01

    Results obtained from JET since June 1983 are described which show that this large tokamak behaves in a similar manner to smaller tokamaks, but with correspondingly improved plasma parameters. Long-duration hydrogen and deuterium plasmas (>10 s) have been obtained with electron temperatures reaching >4 keV for power dissipations =1.6), loss of vertical stability occurred, as expected from previous calculations. Forces of several hundred tonnes (at Isub(p)=2.7 MA) were transmitted to the vacuum vessel. Measured confinement times are larger than the corresponding INTOR values. The maximum achievable density is limited by disruptions. Impurity levels determine this limiting density, and the paper concludes with proposals to reduce these. In addition, progress in neutral injection and RF heating is described, as well as preparations for D-T operation. (author)

  3. JET flywheel generators

    International Nuclear Information System (INIS)

    Huart, M.; Sonnerup, L.

    1986-01-01

    Two large vertical shaft flywheel generators each provides the JET device with peak power up to 400 MW and energy up to 2600 MJ per pulse to induce and confine the multi-mega-ampere plasma current. The integrated rotor flywheel consists of a 650 tonne/10 m diameter rim carrying the poles of the machine. The energy is stored kinetically during a 9 min interval of acceleration from half-speed to full-speed and then released during a 20 s long deceleration. A design life of 100 000 cycles at full energy rating was specified. The mechanical design and construction of the generators is reviewed. Particular attention is paid to the assessment of the stresses and fatigue life of the rotor system, its dynamic behaviour (rim movement, critical speed and balancing) and on the performance in operation of the large thrust bearing. (author)

  4. JET pump limiter

    International Nuclear Information System (INIS)

    Sonnenberg, K.; Deksnis, E.; Shaw, R.; Reiter, D.

    1988-01-01

    JET plans to install two pump limiter modules which can be used for belt-limiter, inner-wall and X-point discharges and, also, for 1-2s as the main limiter. A design is presented which is compatible with two diagnostic systems, and which allows partial removal of the pump limiter to provide access for remote-handling operations. The high heat-flux components are initially cooled during a pulse. Heat is removed between discharges by radiation and pressure contacts to a water-cooled support structure. The pumping edge will be made of annealed pyrolytic graphite. Exhaust efficiency has been estimated, for a 1-d edge model, using a Monte-Carlo calculation of neutral gas transport. When the pump limiter is operated together with other wall components we expect an efficiency of ≅ 5% (2.5 x 10 21 part/s). As a main limiter the efficiency increases to about 10%. (author)

  5. Numerical study of an impinging jet to a turbulent channel flow in a T-Junction configuration

    Science.gov (United States)

    Georgiou, Michail; Papalexandris, Miltiadis

    2016-11-01

    In this talk we report on Large Eddy Simulations of an impinging planar jet to a turbulent channel flow in a T-Junction configuration. Due to its capacity for mixing and heat transfer enhancement, this type of flow is encountered in various industrial applications. In particular, our work is related to the emergency cooling systems of pressurized water reactors. As is well known, this type of flow is dominated by a large separation bubble downstream the jet impingement location. Secondary regions of flow separation are predicted both upstream and downstream the impinging jet. We describe how these separation regions interact with the shear layer that is formed by the injection of the jet to the crossflow, and how they affect the mixing process. In our talk we further examine the influence of the jet's velocity to characteristic quantities of the jet, such as penetration length and expansion angle, as well as to the first and second-order statistics of the flow.

  6. Clues from Bent Jets

    Science.gov (United States)

    Kohler, Susanna

    2018-04-01

    Powerful jets emitted from the centers of distant galaxies make for spectacular signposts in the radio sky. Can observations of these jets reveal information about the environments that surround them?Signposts in the SkyVLA FIRST images of seven bent double-lobed radio galaxies from the authors sample. [Adapted from Silverstein et al. 2018]An active supermassive black hole lurking in a galactic center can put on quite a show! These beasts fling out accreting material, often forming intense jets that punch their way out of their host galaxies. As the jets propagate, they expand into large lobes of radio emission that we can spot from Earth observable signs of the connection between distant supermassive black holes and the galaxies in which they live.These distinctive double-lobed radio galaxies (DLRGs) dont all look the same. In particular, though the jets are emitted from the black holes two poles, the lobes of DLRGs dont always extend perfectly in opposite directions; often, the jets become bent on larger scales, appearing to us to subtend angles of less than 180 degrees.Can we use our observations of DLRG shapes and distributions to learn about their surroundings? A new study led by Ezekiel Silverstein (University of Michigan) has addressed this question by exploring DLRGs living in dense galaxy-cluster environments.Projected density of DLRGcentral galaxy matches (black) compared to a control sample of random positionscentral galaxy matches (red) for different distances from acluster center. DLRGs have a higher likelihood of being located close to a cluster center. [Silverstein et al. 2018]Living Near the HubTo build a sample of DLRGs in dense environments, Silverstein and collaborators started from a large catalog of DLRGs in Sloan Digital Sky Survey quasars with radio lobes visible in Very Large Array data. They then cross-matched these against three galaxy catalogs to produce a sample of 44 DLRGs that are each paired to a nearby massive galaxy, galaxy group

  7. Relativistic Hydrodynamics and Spectral Evolution of GRB Jets

    Science.gov (United States)

    Cuesta-Martínez, C.

    2017-09-01

    In this thesis we study the progenitor systems of long gamma-ray bursts (GRBs) using numerical models of their dynamics and the electromagnetic emission. Of all the possible classes of events, we focus on those showing a prominent component of thermal emission, which might be generated due to the interaction of a relativistic jet with the medium into which it is propagating. The main part of the thesis is devoted to modelling GRBs from two different clases of progenitors: ultra-long GRBs dominated by blackbody emission and GRBs associated with core-collapse supernovae (SNe). The study of GRB jets and their radiative emission has been basically divided into two steps. First, the dynamical evolution of relativistic jets can be simulated by means of multidimensional special relativistic hydrodynamic simulations which have been performed with the MRGENESIS code. Second, the synthetic emission from such jets is computed with the relativistic radiative transfer code SPEV in a post-processing stage assuming different radiative processes in which we follow the temporal and spectral evolution of the emitted radiation. An instrumental part of this project consisted in extending SPEV to include thermal processes, such as thermal bremsstrahlung, in order to account for the thermal signal that may arise in some GRBs. In the first part of this thesis, we extend an existing theoretical model to explain the class of blackbody-dominated GRBs (BBD-GRBs), i.e., long lasting events characterized by the presence of a notable thermal component trailing the GRB prompt emission, and a rather weak traditional afterglow. GRB 101225A, the "Christmas burst", is the most prominent member of this class. It has been suggested that BBD-GRBs could result from the merger of a binary system formed by a neutron star and the Helium core of an evolved, massive star. We model in 2D the propagation of ultrarelativistic jets through the environments created by such mergers. We outline the most relevant

  8. Dominant investors and strategic transparency

    NARCIS (Netherlands)

    Perotti, E.C.; von Thadden, E.-L.

    1998-01-01

    This paper studies product market competition under a strategic transparency decision. Dominant investors can influence information collection in the financial market, and thereby corporate transparency, by affecting market liquidity or the cost of information collection. More transparency on a

  9. Dominant investors and strategic transparency

    NARCIS (Netherlands)

    Perotti, E.C.; von Thadden, E.-L.

    1999-01-01

    This paper studies product market competition under a strategic transparency decision. Dominant investors can influence information collection in the financial market, and thereby corporate transparency, by affecting market liquidity or the cost of information collection. More transparency on a

  10. WHAT GOVERNS THE BULK VELOCITY OF THE JET COMPONENTS IN ACTIVE GALACTIC NUCLEI?

    International Nuclear Information System (INIS)

    Chai Bo; Cao Xinwu; Gu Minfeng

    2012-01-01

    We use a sample of radio-loud active galactic nuclei (AGNs) with measured black hole masses to explore the jet formation mechanisms in these sources. Based on Königl's inhomogeneous jet model, the jet parameters, such as the bulk motion Lorentz factor, magnetic field strength, and electron density in the jet, can be estimated with the very long baseline interferometry and X-ray data.. We find a significant correlation between black hole mass and the bulk Lorentz factor of the jet components for this sample, while no significant correlation is present between the bulk Lorentz factor and the Eddington ratio. The massive black holes will be spun up through accretion, as the black holes acquire mass and angular momentum simultaneously through accretion. Recent investigation indeed suggested that most supermassive black holes in elliptical galaxies have on average higher spins than the black holes in spiral galaxies, where random, small accretion episodes (e.g., tidally disrupted stars, accretion of molecular clouds) might have played a more important role. If this is true, then the correlation between black hole mass and the bulk Lorentz factor of the jet components found in this work implies that the motion velocity of the jet components is probably governed by the black hole spin. No correlation is found between the magnetic field strength at 10R S (R S = 2GM/c 2 is the Schwarzschild radius) in the jets and the bulk Lorentz factor of the jet components for this sample. This is consistent with the black hole spin scenario, i.e., the faster moving jets are magnetically accelerated by the magnetic fields threading the horizon of more rapidly rotating black holes. The results imply that the Blandford-Znajek mechanism may dominate over the Blandford-Payne mechanism for the jet acceleration, at least in these radio-loud AGNs.

  11. A multimaterial electrohydrodynamic jet (E-jet) printing system

    International Nuclear Information System (INIS)

    Sutanto, E; Shigeta, K; Kim, Y K; Graf, P G; Hoelzle, D J; Barton, K L; Alleyne, A G; Ferreira, P M; Rogers, J A

    2012-01-01

    Electrohydrodynamic jet (E-jet) printing has emerged as a high-resolution alternative to other forms of direct solution-based fabrication approaches, such as ink-jet printing. This paper discusses the design, integration and operation of a unique E-jet printing platform. The uniqueness lies in the ability to utilize multiple materials in the same overall print-head, thereby enabling increased degrees of heterogeneous integration of different functionalities on a single substrate. By utilizing multiple individual print-heads, with a carrousel indexing among them, increased material flexibility is achieved. The hardware design and system operation for a relatively inexpensive system are developed and presented. Crossover interconnects and multiple fluorescent tagged proteins, demonstrating printed electronics and biological sensing applications, respectively. (paper)

  12. Particle distributions in ordered jets

    International Nuclear Information System (INIS)

    Zarmi, Y.; Kogan, E.

    1978-01-01

    Assuming specific assumptions about the space-time evolution of hadronic jets, within the framework of a Monte-Carlo calculation, the transverse and longitudinal momentum distributins of particles within the jets are obtained. The transverse momentum distributions are sensitive to the space-time evolution picture. The observed energy dependence of the average transverse momentum and the well known seagull effect are qualitatively reproduced within a picture in which Slow particles in a jet are produced First, and Fast ones - Last (SFFL). (author)

  13. Jet Joint Undertaking. Vol. 2

    International Nuclear Information System (INIS)

    1989-06-01

    The scientific, technical, experimental and theoretical investigations related to JET tokamak are presented. The JET Joint Undertaking, Volume 2, includes papers presented at: the 15th European Conference on controlled fusion and plasma heating, the 15th Symposium on fusion technology, the 12th IAEA Conference on plasma physics and controlled nuclear fusion research, the 8th Topical Meeting on technology of fusion. Moreover, the following topics, concerning JET, are discussed: experience with wall materials, plasma performance, high power ion cyclotron resonance heating, plasma boundary, results and prospects for fusion, preparation for D-T operation, active gas handling system and remote handling equipment

  14. Jet Joint Undertaking. Progress report 1990

    International Nuclear Information System (INIS)

    1991-03-01

    This JET Progress Reports provides an overview summary and puts into context the scientific and technical advances made on JET during 1990. In addition, the Report is supplemented by appendices of contributions (in preprint form) of the more important JET articles published during the year, which set out the details of JET activities

  15. A note on isolate domination

    Directory of Open Access Journals (Sweden)

    Ismail Sahul Hamid

    2016-04-01

    Full Text Available A set $S$ of vertices of a graph $G$ such that $\\left\\langle S\\right\\rangle$ has an isolated vertex is called an \\emph{isolate set} of $G$. The minimum and maximum cardinality of a maximal isolate set are called the \\emph{isolate number} $i_0(G$ and the \\emph{upper isolate number} $I_0(G$ respectively. An isolate set that is also a dominating set (an irredundant set is an $\\emph{isolate dominating set} \\ (\\emph{an isolate irredundant set}$. The \\emph{isolate domination number} $\\gamma_0(G$ and the \\emph{upper isolate domination number} $\\Gamma_0(G$ are respectively the minimum and maximum cardinality of a minimal isolate dominating set while the \\emph{isolate irredundance number} $ir_0(G$ and the \\emph{upper isolate irredundance number} $IR_0(G$ are the minimum and maximum cardinality of a maximal isolate irredundant set of $G$. The notion of isolate domination was introduced in \\cite{sb} and the remaining were introduced in \\cite{isrn}. This paper further extends a study of these parameters.   

  16. Neural mechanisms of social dominance

    Science.gov (United States)

    Watanabe, Noriya; Yamamoto, Miyuki

    2015-01-01

    In a group setting, individuals' perceptions of their own level of dominance or of the dominance level of others, and the ability to adequately control their behavior based on these perceptions are crucial for living within a social environment. Recent advances in neural imaging and molecular technology have enabled researchers to investigate the neural substrates that support the perception of social dominance and the formation of a social hierarchy in humans. At the systems' level, recent studies showed that dominance perception is represented in broad brain regions which include the amygdala, hippocampus, striatum, and various cortical networks such as the prefrontal, and parietal cortices. Additionally, neurotransmitter systems such as the dopaminergic and serotonergic systems, modulate and are modulated by the formation of the social hierarchy in a group. While these monoamine systems have a wide distribution and multiple functions, it was recently found that the Neuropeptide B/W contributes to the perception of dominance and is present in neurons that have a limited projection primarily to the amygdala. The present review discusses the specific roles of these neural regions and neurotransmitter systems in the perception of dominance and in hierarchy formation. PMID:26136644

  17. Neural mechanisms of social dominance

    Directory of Open Access Journals (Sweden)

    Noriya eWatanabe

    2015-06-01

    Full Text Available In a group setting, individuals’ perceptions of their own level of dominance or of the dominance level of others, and the ability to adequately control their behavior based on these perceptions are crucial for living within a social environment. Recent advances in neural imaging and molecular technology have enabled researchers to investigate the neural substrates that support the perception of social dominance and the formation of a social hierarchy in humans. At the systems’ level, recent studies showed that dominance perception is represented in broad brain regions which include the amygdala, hippocampus, striatum, and various cortical networks such as the prefrontal, and parietal cortices. Additionally, neurotransmitter systems such as the dopaminergic and serotonergic systems, modulate and are modulated by the formation of the social hierarchy in a group. While these monoamine systems have a wide distribution and multiple functions, it was recently found that the Neuropeptide B/W contributes to the perception of dominance and is present in neurons that have a limited projection primarily to the amygdala. The present review discusses the specific roles of these neural regions and neurotransmitter systems in the perception of dominance and in hierarchy formation.

  18. Jet reconstruction and heavy jet tagging at LHCb

    CERN Multimedia

    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.

  19. Annular Impinging Jet Controlled by Radial Synthetic Jets

    Czech Academy of Sciences Publication Activity Database

    Trávníček, Zdeněk; Tesař, Václav; Broučková, Zuzana; Peszyński, K.

    2014-01-01

    Roč. 35, 16-17 (2014), s. 1450-1461 ISSN 0145-7632 R&D Projects: GA ČR GA14-08888S; GA AV ČR(CZ) IAA200760801 Institutional support: RVO:61388998 Keywords : impinging jet * hybrid synthetic jet * flow control Subject RIV: JU - Aeronautics, Aerodynamics, Aircrafts Impact factor: 0.814, year: 2014 http://dx.doi.org/10.1080/01457632.2014.889467

  20. Improved core electron confinement on JET

    International Nuclear Information System (INIS)

    Litaudon, X.; Baranov, Y.; Voitsekhovitch, I.

    1999-01-01

    Formation of core regions with reduced electron transport is reported in regimes with current profile shaping at JET. The electron heat diffusivity (Χ c ) is reduced down to 0.5 m 2 /s in the region of low magnetic shear with an ICRH power of 1 MW with no indication of a threshold. In the high performance optimised shear regime, obtained in scenarios dominated by ion heating, internal transport barriers on the ion temperature profiles are simultaneously accompanied by a significant reduction of the electron heat diffusivity at two-third of the plasma radius. In this regime, recent results and measurements obtained with the new gas-box divertor configuration are reported together with their transport analyses. The results indicate that Χ c is reduced by one order of magnitude in a spatially localised region. (authors)

  1. Characterization of plasma current quench at JET

    International Nuclear Information System (INIS)

    Riccardo, V; Barabaschi, P; Sugihara, M

    2005-01-01

    Eddy currents generated during the fastest disruption current decays represent the most severe design condition for medium and small size in-vessel components of most tokamaks. Best-fit linear and instantaneous plasma current quench rates have been extracted for a set of recent JET disruptions. Contrary to expectations, the current quench rate spectrum of high and low thermal energy disruptions is not substantially different. For most of the disruptions with the highest instantaneous current quench rate an exponential fit of the early phase of the current decay provides a more accurate estimate of the maximum current decay velocity. However, this fit is only suitable to model the fastest events, for which the current quench is dominated by radiation losses rather than the plasma motion

  2. Uncovering Nature’s 100 TeV Particle Accelerators in the Large-Scale Jets of Quasars

    Science.gov (United States)

    Georganopoulos, Markos; Meyer, Eileen; Sparks, William B.; Perlman, Eric S.; Van Der Marel, Roeland P.; Anderson, Jay; Sohn, S. Tony; Biretta, John A.; Norman, Colin Arthur; Chiaberge, Marco

    2016-04-01

    Since the first jet X-ray detections sixteen years ago the adopted paradigm for the X-ray emission has been the IC/CMB model that requires highly relativistic (Lorentz factors of 10-20), extremely powerful (sometimes super-Eddington) kpc scale jets. R I will discuss recently obtained strong evidence, from two different avenues, IR to optical polarimetry for PKS 1136-135 and gamma-ray observations for 3C 273 and PKS 0637-752, ruling out the EC/CMB model. Our work constrains the jet Lorentz factors to less than ~few, and leaves as the only reasonable alternative synchrotron emission from ~100 TeV jet electrons, accelerated hundreds of kpc away from the central engine. This refutes over a decade of work on the jet X-ray emission mechanism and overall energetics and, if confirmed in more sources, it will constitute a paradigm shift in our understanding of powerful large scale jets and their role in the universe. Two important findings emerging from our work will also discussed be: (i) the solid angle-integrated luminosity of the large scale jet is comparable to that of the jet core, contrary to the current belief that the core is the dominant jet radiative outlet and (ii) the large scale jets are the main source of TeV photon in the universe, something potentially important, as TeV photons have been suggested to heat up the intergalactic medium and reduce the number of dwarf galaxies formed.

  3. Characteristics and generation of secondary jets and secondary gigantic jets

    Science.gov (United States)

    Lee, Li-Jou; Huang, Sung-Ming; Chou, Jung-Kung; Kuo, Cheng-Ling; Chen, Alfred B.; Su, Han-Tzong; Hsu, Rue-Rou; Frey, Harald U.; Takahashi, Yukihiro; Lee, Lou-Chuang

    2012-06-01

    Secondary transient luminous events (TLEs) recorded by the ISUAL-FORMOSAT2 mission can either be secondary jets or secondary gigantic jets (GJs), depending on their terminal altitudes. The secondary jets emerge from the cloud top beneath the preceding sprites and extend upward to the base of the sprites at ˜50 km. The secondary jets likely are negative electric discharges with vertically straight luminous columns, morphologically resembling the trailing jet of the type-I GJs. The number of luminous columns in a secondary jet seems to be affected by the size of the effective capacitor plate formed near the base of the preceding sprites and the charge distribution left behind by the sprite-inducing positive cloud-to-ground discharges. The secondary GJs originate from the cloud top under the shielding area of the preceding sprites, and develop upward to reach the lower ionosphere at ˜90 km. The observed morphology of the secondary GJs can either be the curvy shifted secondary GJs extending outside the region occupied by the preceding sprites or the straight pop-through secondary GJs developing through the center of the preceding circular sprites. A key factor in determining the terminal height of the secondary TLEs appears to be the local ionosphere boundary height that established by the preceding sprites. The abundance and the distribution of the negative charge in the thundercloud following the sprite-inducing positive cloud-to-ground discharges may play important role in the generation of the secondary TLEs.

  4. Equatorial jet - a case study

    Digital Repository Service at National Institute of Oceanography (India)

    Muraleedharan, P.M.; PrasannaKumar, S.

    analysis of hydrographic data of 1964 is also carried out to understand the response signature of water column to prevailing westerlies. A jet forms in the Central Indian Ocean which gathers momentum as it advances eastward. Sinking of the thermocline...

  5. Jets in heavy ion collisions

    International Nuclear Information System (INIS)

    Nattrass, Christine

    2017-01-01

    High energy collisions of heavy nuclei permit the study of nuclear matter at temperatures and energy densities so high that the fundamental theory for strong interactions, QCD, predicts a phase transition to a plasma of quarks and gluons. This matter, called a Quark Gluon Plasma (QGP), has been studied experimentally for the last decade and has been observed to be a strongly interacting liquid with a low viscosity. High energy partons created early in the collision interact with the QGP and provide unique probes of its properties. Hard partons fragment into collimated sprays of particles called jets and have been studied through measurements of single particles, correlations between particles, and measurements of fully reconstructed jets. These measurements demonstrate partonic energy loss in the QGP and constrain the QGP’s properties. Measurements of the jet structure give insight into the mechanism of this energy loss. The information we have learned from studies of jets and challenges for the field will be reviewed. (paper)

  6. Jet-quenching and correlations

    Indian Academy of Sciences (India)

    2015-05-06

    May 6, 2015 ... pseudorapidity (ridge) correlations in small systems. Section 7 ... words of 'jet' and 'parton' are often used interchangeably. ...... [118] STAR Collaboration: Joshua Konzer, Poster presentation at Quark Matter 2012 (2012).

  7. Jet calculus beyond leading logarithms

    International Nuclear Information System (INIS)

    Kalinowski, J.; Konishi, K.; Taylor, T.R.

    1981-01-01

    It is shown that the evolution of hadronic jets produced in hard processes can be studied in terms of a simple parton branching picture, beyond the leading log approximation of QCD. The jet calculus is generalized to any given order of logs (but always to all orders of αsub(s)). We discuss the general structure of the formalism. Universality of jet evolution is discussed. We consider also a jet calorimetry measure and the multiplicity distribution of final states in a form which allows a systematic improvement of approximation. To the next-to-leading order, we prove the finiteness and elucidate the scheme dependence of parton subprocess probabilities. The physical inclusive cross section is shown to be scheme independent: next-to-leading results for e + e - → q (nonsinglet) + X agree with those of Curci and others. (orig.)

  8. Jets in deep inelastic scattering

    International Nuclear Information System (INIS)

    Joensson, L.

    1995-01-01

    Jet production in deep inelastic scattering provides a basis for the investigation of various phenomena related to QCD. Two-jet production at large Q 2 has been studied and the distributions with respect to the partonic scaling variables have been compared to models and to next to leading order calculations. The first observations of azimuthal asymmetries of jets produced in first order α s processes have been obtained. The gluon initiated boson-gluon fusion process permits a direct determination of the gluon density of the proton from an analysis of the jets produced in the hard scattering process. A comparison of these results with those from indirect extractions of the gluon density provides an important test of QCD. (author)

  9. 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.

  10. Comparisons of Jet Properties between GeV Radio Galaxies and Blazars

    Science.gov (United States)

    Xue, Zi-Wei; Zhang, Jin; Cui, Wei; Liang, En-Wei; Zhang, Shuang-Nan

    2017-09-01

    We compile a sample of spectral energy distributions (SEDs) of 12 GeV radio galaxies (RGs), including eight FR I RGs and four FR II RGs. These SEDs can be represented with the one-zone leptonic model. No significant unification, as expected in the unification model, is found for the derived jet parameters between FR I RGs and BL Lacertae objects (BL Lacs) and between FR II RGs and flat spectrum radio quasars (FSRQs). However, on average FR I RGs have a larger {γ }{{b}} (break Lorentz factor of electrons) and lower B (magnetic field strength) than FR II RGs, analogous to the differences between BL Lacs and FSRQs. The derived Doppler factors (δ) of RGs are on average smaller than those of blazars, which is consistent with the unification model such that RGs are the misaligned parent populations of blazars with smaller δ. On the basis of jet parameters from SED fits, we calculate their jet powers and the powers carried by each component, and compare their jet compositions and radiation efficiencies with blazars. Most of the RG jets may be dominated by particles, like BL Lacs, not FSRQs. However, the jets of RGs with higher radiation efficiencies tend to have higher jet magnetization. A strong anticorrelation between synchrotron peak frequency and jet power is observed for GeV RGs and blazars in both the observer and co-moving frames, indicating that the “sequence” behavior among blazars, together with the GeV RGs, may be intrinsically dominated by jet power.

  11. Measurement of differential di-photon plus jet cross sections using the ATLAS detector

    Energy Technology Data Exchange (ETDEWEB)

    Bessner, Martin Florian

    2017-08-15

    A good understanding of the strong interaction is crucial for every experiment at a hadron collider. Events with photons provide a direct access to study processes of the strong interaction. This thesis presents the measurement of differential cross sections of events with two photons as a function of the number of hadronic jets. Photons are required to be isolated from hadronic activity in the event. Collision data is used corresponding to an integrated luminosity of 20.3 fb{sup -1} at a proton-proton collision energy of √(s)=8 TeV collected by the ATLAS detector at the Large Hadron Collider (LHC) in 2012. The dominant background contribution comes from hadronic jets which are identified as photons, occurring mainly when a π{sup 0} carries most of the jet energy. Two methods to remove this contribution are presented. A smaller background contribution arising from electrons misidentified as photons is removed as well. The measured event yields are corrected for detector inefficiencies and resolution effects. An unfolding method based on singular value decomposition of the resolution matrix is extended to two-dimensional distributions and applied to the reconstructed distributions. All systematic uncertainties are evaluated, the dominant uncertainties arise from the jet background subtraction and the uncertainty in the jet energy scale. 16 observables are studied to explore the photon and jet kinematics. Double differential cross sections are shown as function of those observables and the number of jets, both inclusively (≥n jets) and exclusively (=n jets). The results are compared to theoretical predictions from Sherpa, Pythia and GoSam.

  12. Measurement of differential di-photon plus jet cross sections using the ATLAS detector

    International Nuclear Information System (INIS)

    Bessner, Martin Florian

    2017-08-01

    A good understanding of the strong interaction is crucial for every experiment at a hadron collider. Events with photons provide a direct access to study processes of the strong interaction. This thesis presents the measurement of differential cross sections of events with two photons as a function of the number of hadronic jets. Photons are required to be isolated from hadronic activity in the event. Collision data is used corresponding to an integrated luminosity of 20.3 fb"-"1 at a proton-proton collision energy of √(s)=8 TeV collected by the ATLAS detector at the Large Hadron Collider (LHC) in 2012. The dominant background contribution comes from hadronic jets which are identified as photons, occurring mainly when a π"0 carries most of the jet energy. Two methods to remove this contribution are presented. A smaller background contribution arising from electrons misidentified as photons is removed as well. The measured event yields are corrected for detector inefficiencies and resolution effects. An unfolding method based on singular value decomposition of the resolution matrix is extended to two-dimensional distributions and applied to the reconstructed distributions. All systematic uncertainties are evaluated, the dominant uncertainties arise from the jet background subtraction and the uncertainty in the jet energy scale. 16 observables are studied to explore the photon and jet kinematics. Double differential cross sections are shown as function of those observables and the number of jets, both inclusively (≥n jets) and exclusively (=n jets). The results are compared to theoretical predictions from Sherpa, Pythia and GoSam.

  13. Centrifuge pellet injector for JET

    International Nuclear Information System (INIS)

    Andelfinger, C.; Buchelt, E.; Jacobi, D.; Lackner, E.; Schilling, H.B.; Ulrich, M.; Weber, G.

    1983-08-01

    An engineering design of a centrifuge pellet injector for JET is reported as part of the Phase I contract number JE 2/9016. A rather detailed design is presented for the mechanical and electronic features. Stress calculations, dynamic behaviour and life estimates are considered. The interfaces to the JET vacuum system and CODAS are discussed. Proposals for the pellet diagnostics (velocity, mass and shape) are presented. (orig.)

  14. 4-jet events at LEP

    CERN Document Server

    Bizouard, M A

    1997-01-01

    Results of a special study made by the four LEP experiments on 4-jet events recorded at Vs = 130 - 136 , 161 and 172 GeV are related. This study concerns the ALEPH analysis which has shown an excess of 4-jet events in data recorded at Vs = 130 - 136 GeV. No significant evidence has been found by the 3 other experiments. Results have been combined after several checks which did not show differences of performance between the four LEP experiments.

  15. Overview of JET results

    International Nuclear Information System (INIS)

    Pamela, J.

    2003-01-01

    Scientific and technical activities on JET focus on the issues likely to affect the ITER design and operation. The physics of the ITER reference mode of operation, the ELMy H-mode, has progressed significantly: the extrapolation of ELM size to ITER has been re-evaluated; NTMs have been shown to be metastable in JET, and can be avoided via sawtooth destabilisation by ICRH; α-simulation experiments were carried out by accelerating 4 He beam ions by ICRH, providing a new tool for fast particle and MHD studies with up to 80-90% of plasma heating by fast 4 He ions. With or without impurity seeding, quasi-steady sate high confinement (H 98 =1), high density (n e /n GR = 0.9-1) and high β (β N =2) ELMy H-mode has been achieved by operating near the ITER triangularity (δ∼0.40-0.5) and safety factor (q 95 ∼3), at Z eff ∼1.5-2. In Advanced Tokamak scenarios, internal transport barriers are now characterised in real time with a new criterion ρ* T ; tailoring of the current profile with LHCD provides reliable access to a variety of q profiles, with significantly lowered access power for barrier formation; rational q surfaces appear to be associated with ITB formation; Alfven cascades are observed in RS plasmas, providing an identification of q profile evolution; plasmas with 'current holes' were observed and explained by modelling. Transient high confinement Advanced Tokamak regimes with H89=3.3, β N =2.4 and ITER relevant q<5 are achievable in reversed magnetic shear. Quasistationary internal transport barriers are developed with full non-inductive current drive, including ∼50% bootstrap current. Record duration of ITBs was achieved, up to 11 s, approaching the resistive time. Pressure and current profiles of Advanced Tokamak regimes are controlled by a real time feedback system, in separate experiments. The erosion and co-deposition data base progressed significantly, in particular with a new quartz microbalance diagnostic allowing shot by shot measurements of

  16. Transverse jets and their control

    Energy Technology Data Exchange (ETDEWEB)

    Karagozian, Ann R. [Department of Mechanical and Aerospace Engineering, University of California, 48-121 Engineering IV, Los Angeles, CA 90095 (United States)

    2010-10-15

    The jet in crossflow or transverse jet has been studied extensively because of its relevance to a wide variety of flows in technological systems, including fuel or dilution air injection in gas turbine engines, thrust vector control for high speed airbreathing and rocket vehicles, and exhaust plumes from power plants. These widespread applications have led over the past 50+ years to experimental, theoretical, and numerical examinations of this fundamental flowfield, with and without a combustion reaction, and with single or multi-phase flow. The complexities in this flowfield, whether the jet is introduced flush with respect to the injection wall or from an elevated pipe or nozzle, present challenges in accurately interrogating, analyzing, and simulating important jet features. This review article provides a background on these studies and applications as well as detailed features of the transverse jet, and mechanisms for its control via active means. Promising future directions for the understanding, interrogation, simulation, and control of transverse jet flows are also identified and discussed. (author)

  17. Measurement of inclusive jet and dijet cross sections in proton-proton collisions at 7 TeV centre-of-mass energy with the ATLAS detector

    CERN Document Server

    Aad, G.; Abdallah, J.; Abdelalim, A.A.; Abdesselam, A.; Abdinov, O.; Abi, B.; Abolins, M.; Abramowicz, H.; Abreu, H.; Acerbi, E.; Acharya, B.S.; Ackers, M.; Adams, D.L.; Addy, T.N.; Adelman, J.; Aderholz, M.; Adomeit, S.; Adorisio, C.; Adragna, P.; Adye, T.; Aefsky, S.; Aguilar-Saavedra, J.A.; Aharrouche, M.; Ahlen, S.P.; Ahles, F.; Ahmad, A.; Ahmed, H.; Ahsan, M.; Aielli, G.; Akdogan, T.; Akesson, T.P.A.; Akimoto, G.; Akimov, A.V.; Aktas, A.; Alam, M.S.; Alam, M.A.; Albrand, S.; Aleksa, M.; Aleksandrov, I.N.; Aleppo, M.; Alessandria, F.; Alexa, C.; Alexander, G.; Alexandre, G.; Alexopoulos, T.; Alhroob, M.; Aliev, M.; Alimonti, G.; Alison, J.; Aliyev, M.; Allport, P.P.; Allwood-Spiers, S.E.; Almond, J.; Aloisio, A.; Alon, R.; Alonso, A.; Alonso, J.; Alviggi, M.G.; Amako, K.; Amaral, P.; Ambrosio, G.; Amelung, C.; Ammosov, V.V.; Amorim, A.; Amoros, G.; Amram, N.; Anastopoulos, C.; Andeen, T.; Anders, C.F.; Anderson, K.J.; Andreazza, A.; Andrei, V.; Andrieux, M-L.; Anduaga, X.S.; Angerami, A.; Anghinolfi, F.; Anjos, N.; Annovi, A.; Antonaki, A.; Antonelli, M.; Antonelli, S.; Antos, J.; Antunovic, B.; Anulli, F.; Aoun, S.; Arabidze, G.; Aracena, I.; Arai, Y.; Arce, A.T.H.; Archambault, J.P.; Arfaoui, S.; Arguin, J-F.; Argyropoulos, T.; Arik, E.; Arik, M.; Armbruster, A.J.; Arms, K.E.; Armstrong, S.R.; Arnaez, O.; Arnault, C.; Artamonov, A.; Arutinov, D.; Asai, M.; Asai, S.; Asfandiyarov, R.; Ask, S.; Asman, B.; Asner, D.; Asquith, L.; Assamagan, K.; Astbury, A.; Astvatsatourov, A.; Atoian, G.; Aubert, B.; Auerbach, B.; Auge, E.; Augsten, K.; Aurousseau, M.; Austin, N.; Avolio, G.; Avramidou, R.; Axen, D.; Ay, C.; Azuelos, G.; Azuma, Y.; Baak, M.A.; Baccaglioni, G.; Bacci, C.; Bach, A.M.; Bachacou, H.; Bachas, K.; Bachy, G.; Backes, M.; Badescu, E.; Bagnaia, P.; Bai, Y.; Bailey, D.C.; Bain, T.; Baines, J.T.; Baker, O.K.; Baker, M.D.; Baker, S; Baltasar Dos Santos Pedrosa, F.; Banas, E.; Banerjee, P.; Banerjee, Sw.; Banfi, D.; Bangert, A.; Bansal, V.; Baranov, S.P.; Baranov, S.; Barashkou, A.; Barbaro Galtieri, A.; Barber, T.; Barberio, E.L.; Barberis, D.; Barbero, M.; Bardin, D.Y.; Barillari, T.; Barisonzi, M.; Barklow, T.; Barlow, N.; Barnett, B.M.; Barnett, R.M.; Baroncelli, A.; Barone, M.; Barr, A.J.; Barreiro, F.; Barreiro Guimaraes da Costa, J.; Barrillon, P.; Bartoldus, R.; Bartsch, D.; Bates, R.L.; Batkova, L.; Batley, J.R.; Battaglia, A.; Battistin, M.; Battistoni, G.; Bauer, F.; Bawa, H.S.; Bazalova, M.; Beare, B.; Beau, T.; Beauchemin, P.H.; Beccherle, R.; Bechtle, P.; Beck, G.A.; Beck, H.P.; Beckingham, M.; Becks, K.H.; Beddall, A.J.; Beddall, A.; Bednyakov, V.A.; Bee, C.; Begel, M.; Behar Harpaz, S.; Behera, P.K.; Beimforde, M.; Belanger-Champagne, C.; Belhorma, B.; Bell, P.J.; Bell, W.H.; Bella, G.; Bellagamba, L.; Bellina, F.; Bellomo, G.; Bellomo, M.; Belloni, A.; Belotskiy, K.; Beltramello, O.; Ben Ami, S.; Benary, O.; Benchekroun, D.; Benchouk, C.; Bendel, M.; Benedict, B.H.; Benekos, N.; Benhammou, Y.; Benincasa, G.P.; Benjamin, D.P.; Benoit, M.; 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Salvatore, D.; Salvatore, F.; Salvucci, A.; Salzburger, A.; Sampsonidis, D.; Samset, B.H.; Sandaker, H.; Sander, H.G.; Sanders, M.P.; Sandhoff, M.; Sandhu, P.; Sandoval, T.; Sandstroem, R.; Sandvoss, S.; Sankey, D.P.C.; Sanny, B.; Sansoni, A.; Santamarina Rios, C.; Santoni, C.; Santonico, R.; Santos, H.; Saraiva, J.G.; Sarangi, T.; Sarkisyan-Grinbaum, E.; Sarri, F.; Sartisohn, G.; Sasaki, O.; Sasaki, T.; Sasao, N.; Satsounkevitch, I.; Sauvage, G.; Savard, P.; Savine, A.Y.; Savinov, V.; Savva, P.; Sawyer, L.; Saxon, D.H.; Says, L.P.; Sbarra, C.; Sbrizzi, A.; Scallon, O.; Scannicchio, D.A.; Schaarschmidt, J.; Schacht, P.; Schafer, U.; Schaetzel, S.; Schaffer, A.C.; Schaile, D.; Schaller, M.; Schamberger, R.D.; Schamov, A.G.; Scharf, V.; Schegelsky, V.A.; Scheirich, D.; Schernau, M.; Scherzer, M.I.; Schiavi, C.; Schieck, J.; Schioppa, M.; Schlenker, S.; Schlereth, J.L.; Schmidt, E.; Schmidt, M.P.; Schmieden, K.; Schmitt, C.; Schmitz, M.; Scholte, R.C.; Schoning, A.; Schott, M.; Schouten, D.; Schovancova, J.; Schram, M.; Schreiner, A.; Schroeder, C.; Schroer, N.; Schroers, M.; Schroff, D.; Schuh, S.; Schuler, G.; Schultes, J.; Schultz-Coulon, H.C.; Schumacher, J.W.; Schumacher, M.; Schumm, B.A.; Schune, Ph.; Schwanenberger, C.; Schwartzman, A.; Schweiger, D.; Schwemling, Ph.; Schwienhorst, R.; Schwierz, R.; Schwindling, J.; Scott, W.G.; Searcy, J.; Sedykh, E.; Segura, E.; Seidel, S.C.; Seiden, A.; Seifert, F.; Seixas, J.M.; Sekhniaidze, G.; Seliverstov, D.M.; Sellden, B.; Sellers, G.; Seman, M.; Semprini-Cesari, N.; Serfon, C.; Serin, L.; Seuster, R.; Severini, H.; Sevior, M.E.; Sfyrla, A.; Shabalina, E.; Shamim, M.; Shan, L.Y.; Shank, J.T.; Shao, Q.T.; Shapiro, M.; Shatalov, P.B.; Shaver, L.; Shaw, C.; Shaw, K.; Sherman, D.; Sherwood, P.; Shibata, A.; Shield, P.; Shimizu, S.; Shimojima, M.; Shin, T.; Shmeleva, A.; Shochet, M.J.; Shupe, M.A.; Sicho, P.; Sidoti, A.; Siebel, A.; Siegert, F; Siegrist, J.; Sijacki, Dj.; Silbert, O.; Silva, J.; Silver, Y.; Silverstein, D.; Silverstein, S.B.; Simak, V.; Simic, Lj.; Simion, S.; Simmons, B.; Simonyan, M.; Sinervo, P.; Sinev, N.B.; Sipica, V.; Siragusa, G.; Sisakyan, A.N.; Sivoklokov, S.Yu.; Sjolin, J.; Sjursen, T.B.; Skinnari, L.A.; Skovpen, K.; Skubic, P.; Skvorodnev, N.; Slater, M.; Slavicek, T.; Sliwa, K.; Sloan, T.J.; Sloper, J.; Smakhtin, V.; Smirnov, S.Yu.; Smirnov, Y.; Smirnova, L.N.; Smirnova, O.; Smith, B.C.; Smith, D.; Smith, K.M.; Smizanska, M.; Smolek, K.; Snesarev, A.A.; Snow, S.W.; Snow, J.; Snuverink, J.; Snyder, S.; Soares, M.; Sobie, R.; Sodomka, J.; Soffer, A.; Solans, C.A.; Solar, M.; Solc, J.; Solfaroli Camillocci, E.; Solodkov, A.A.; Solovyanov, O.V.; Soluk, R.; Sondericker, J.; Soni, N.; Sopko, V.; Sopko, B.; Sorbi, M.; Sosebee, M.; Soukharev, A.; Spagnolo, S.; Spano, F.; Speckmayer, P.; Spencer, E.; Spighi, R.; Spigo, G.; Spila, F.; Spiriti, E.; Spiwoks, R.; Spogli, L.; Spousta, M.; Spreitzer, T.; Spurlock, B.; St. Denis, R.D.; Stahl, T.; Stahlman, J.; Stamen, R.; Stancu, S.N.; Stanecka, E.; Stanek, R.W.; Stanescu, C.; Stapnes, S.; Starchenko, E.A.; Stark, J.; Staroba, P.; Starovoitov, P.; Stastny, J.; Staude, A.; Stavina, P.; Stavropoulos, G.; Steele, G.; Stefanidis, E.; Steinbach, P.; Steinberg, P.; Stekl, I.; Stelzer, B.; Stelzer, H.J.; Stelzer-Chilton, O.; Stenzel, H.; Stevenson, K.; Stewart, G.A.; Stiller, W.; Stockmanns, T.; Stockton, M.C.; Stodulski, M.; Stoerig, K.; Stoicea, G.; Stonjek, S.; Strachota, P.; Stradling, A.R.; Straessner, A.; Strandberg, J.; Strandberg, S.; Strandlie, A.; Strang, M.; Strauss, M.; Strizenec, P.; Strohmer, R.; Strom, D.M.; Strong, J.A.; Stroynowski, R.; Strube, J.; Stugu, B.; Stumer, I.; Stupak, J.; Sturm, P.; Soh, D.A.; Su, D.; Sugaya, Y.; Sugimoto, T.; Suhr, C.; Suita, K.; Suk, M.; Sulin, V.V.; Sultansoy, S.; Sumida, T.; Sun, X.H.; Sundermann, J.E.; Suruliz, K.; Sushkov, S.; Susinno, G.; Sutton, M.R.; Suzuki, Y.; Sviridov, Yu.M.; Swedish, S.; Sykora, I.; Sykora, T.; Szczygiel, R.R.; Szeless, B.; Szymocha, T.; Sanchez, J.; Ta, D.; Taboada Gameiro, S.; Tackmann, K.; Taffard, A.; Tafirout, R.; Taga, A.; Takahashi, Y.; Takai, H.; Takashima, R.; Takeda, H.; Takeshita, T.; Talby, M.; Talyshev, A.; Tamsett, M.C.; Tanaka, J.; Tanaka, R.; Tanaka, S.; Tanaka, S.; Tanaka, Y.; Tani, K.; Tappern, G.P.; Tapprogge, S.; Tardif, D.; Tarem, S.; Tarrade, F.; Tartarelli, G.F.; Tas, P.; Tasevsky, M.; Tassi, E.; Tatarkhanov, M.; Taylor, C.; Taylor, F.E.; Taylor, G.; Taylor, G.N.; Taylor, R.P.; Taylor, W.; Teixeira Dias Castanheira, M.; Teixeira-Dias, P.; Temming, K.K.; Ten Kate, H.; Teng, P.K.; Tennenbaum-Katan, Y.D.; Terada, S.; Terashi, K.; Terron, J.; Terwort, M.; Testa, M.; Teuscher, R.J.; Tevlin, C.M.; Thadome, J.; Therhaag, J.; Theveneaux-Pelzer, T.; Thioye, M.; Thoma, S.; Thomas, J.P.; Thompson, E.N.; Thompson, P.D.; Thompson, P.D.; Thompson, R.J.; Thompson, A.S.; Thomson, E.; Thomson, M.; Thun, R.P.; Tic, T.; Tikhomirov, V.O.; Tikhonov, Y.A.; Timmermans, C.J.W.P.; Tipton, P.; Tique Aires Viegas, F.J.; Tisserant, S.; Tobias, J.; Toczek, B.; Todorov, T.; Todorova-Nova, S.; Toggerson, B.; Tojo, J.; Tokar, S.; Tokunaga, K.; Tokushuku, K.; Tollefson, K.; Tomasek, L.; Tomasek, M.; Tomoto, M.; Tompkins, D.; Tompkins, L.; Toms, K.; Tonazzo, A.; Tong, G.; Tonoyan, A.; Topfel, C.; Topilin, N.D.; Torchiani, I.; Torrence, E.; Torro Pastor, E.; Toth, J.; Touchard, F.; Tovey, D.R.; Traynor, D.; Trefzger, T.; Treis, J.; Tremblet, L.; Tricoli, A.; Trigger, I.M.; Trincaz-Duvoid, S.; Trinh, T.N.; Tripiana, M.F.; Triplett, N.; Trischuk, W.; Trivedi, A.; Trocme, B.; Troncon, C.; Trottier-McDonald, M.; Trzupek, A.; Tsarouchas, C.; Tseng, J.C-L.; Tsiakiris, M.; Tsiareshka, P.V.; Tsionou, D.; Tsipolitis, G.; Tsiskaridze, V.; Tskhadadze, E.G.; Tsukerman, I.I.; Tsulaia, V.; Tsung, J.W.; Tsuno, S.; Tsybychev, D.; Tuggle, J.M.; Turala, M.; Turecek, D.; Turk Cakir, I.; Turlay, E.; Tuts, P.M.; Twomey, M.S.; Tylmad, M.; Tyndel, M.; Typaldos, D.; Tyrvainen, H.; Tzamarioudaki, E.; Tzanakos, G.; Uchida, K.; Ueda, I.; Ueno, R.; Ugland, M.; Uhlenbrock, M.; Uhrmacher, M.; Ukegawa, F.; Unal, G.; Underwood, D.G.; Undrus, A.; Unel, G.; Unno, Y.; Urbaniec, D.; Urkovsky, E.; Urquijo, P.; Urrejola, P.; Usai, G.; Uslenghi, M.; Vacavant, L.; Vacek, V.; Vachon, B.; Vahsen, S.; Valderanis, C.; Valenta, J.; Valente, P.; Valentinetti, S.; Valkar, S.; Valladolid Gallego, E.; Vallecorsa, S.; Valls Ferrer, J.A.; Van Berg, R.; van der Graaf, H.; van der Kraaij, E.; van der Poel, E.; van der Ster, D.; Van Eijk, B.; van Eldik, N.; van Gemmeren, P.; van Kesteren, Z.; van Vulpen, I.; Vandelli, W.; Vandoni, G.; Vaniachine, A.; Vankov, P.; Vannucci, F.; Varela Rodriguez, F.; Vari, R.; Varnes, E.W.; Varouchas, D.; Vartapetian, A.; Varvell, K.E.; Vasilyeva, L.; Vassilakopoulos, V.I.; Vazeille, F.; Vedrine, P.; Vegni, G.; Veillet, J.J.; Vellidis, C.; Veloso, F.; Veness, R.; Veneziano, S.; Ventura, A.; Ventura, D.; Ventura, S.; Venturi, M.; Venturi, N.; Vercesi, V.; Verducci, M.; Verkerke, W.; Vermeulen, J.C.; Vertogardov, L.; Vetterli, M.C.; Vichou, I.; Vickey, T.; Viehhauser, G.H.A.; Viel, S.; Villa, M.; Villani, E.G.; Villaplana Perez, M.; Vilucchi, E.; Vincter, M.G.; Vinek, E.; Vinogradov, V.B.; Virchaux, M.; Viret, S.; Virzi, J.; Vitale, A.; Vitells, O.; Vivarelli, I.; Vives Vaque, F.; Vlachos, S.; Vlasak, M.; Vlasov, N.; Vogel, A.; Vokac, P.; Volpi, M.; Volpini, G.; von der Schmitt, H.; von Loeben, J.; von Radziewski, H.; von Toerne, E.; Vorobel, V.; Vorobiev, A.P.; Vorwerk, V.; Vos, M.; Voss, R.; Voss, T.T.; Vossebeld, J.H.; Vovenko, A.S.; Vranjes, N.; Vranjes Milosavljevic, M.; Vrba, V.; Vreeswijk, M.; Vu Anh, T.; Vudragovic, D.; Vuillermet, R.; Vukotic, I.; Wagner, W.; Wagner, P.; Wahlen, H.; Walbersloh, J.; Walder, J.; Walker, R.; Walkowiak, W.; Wall, R.; Waller, P.; Wang, C.; Wang, H.; Wang, J.; Wang, J.C.; Wang, S.M.; Warburton, A.; Ward, C.P.; Warsinsky, M.; Wastie, R.; Watkins, P.M.; Watson, A.T.; Watson, M.F.; Watts, G.; Watts, S.; Waugh, A.T.; Waugh, B.M.; Webel, M.; Weber, J.; Weber, M.; Weber, M.S.; Weber, P.; Weidberg, A.R.; Weingarten, J.; Weiser, C.; Wellenstein, H.; Wells, P.S.; Wen, M.; Wenaus, T.; Wendler, S.; Weng, Z.; Wengler, T.; Wenig, S.; Wermes, N.; Werner, M.; Werner, P.; Werth, M.; Werthenbach, U.; Wessels, M.; Whalen, K.; Wheeler-Ellis, S.J.; Whitaker, S.P.; White, A.; White, M.J.; White, S.; Whitehead, S.R.; Whiteson, D.; Whittington, D.; Wicek, F.; Wicke, D.; Wickens, F.J.; Wiedenmann, W.; Wielers, M.; Wienemann, P.; Wiglesworth, C.; Wiik, L.A.M.; Wildauer, A.; Wildt, M.A.; Wilhelm, I.; Wilkens, H.G.; Will, J.Z.; Williams, E.; Williams, H.H.; Willis, W.; Willocq, S.; Wilson, J.A.; Wilson, M.G.; Wilson, A.; Wingerter-Seez, I.; Winkelmann, S.; Winklmeier, F.; Wittgen, M.; Wolter, M.W.; Wolters, H.; Wosiek, B.K.; Wotschack, J.; Woudstra, M.J.; Wraight, K.; Wright, C.; Wright, D.; Wrona, B.; Wu, S.L.; Wu, X.; Wuestenfeld, J.; Wulf, E.; Wunstorf, R.; Wynne, B.M.; Xaplanteris, L.; Xella, S.; Xie, S.; Xie, Y.; Xu, C.; Xu, D.; Xu, G.; Xu, N.; Yabsley, B.; Yamada, M.; Yamamoto, A.; Yamamoto, K.; Yamamoto, S.; Yamamura, T.; Yamaoka, J.; Yamazaki, T.; Yamazaki, Y.; Yan, Z.; Yang, H.; Yang, S.; Yang, U.K.; Yang, Y.; Yang, Y.; Yang, Z.; Yanush, S.; Yao, W-M.; Yao, Y.; Yasu, Y.; Ye, J.; Ye, S.; Yilmaz, M.; Yoosoofmiya, R.; Yorita, K.; Yoshida, R.; Young, C.; Youssef, S.P.; Yu, D.; Yu, J.; Yu, J.; Yuan, J.; Yuan, L.; Yurkewicz, A.; Zaets, V.G.; Zaidan, R.; Zaitsev, A.M.; Zajacova, Z.; Zalite, Yo.K.; Zambrano, V.; Zanello, L.; Zarzhitsky, P.; Zaytsev, A.; Zdrazil, M.; Zeitnitz, C.; Zeller, M.; Zema, P.F.; Zemla, A.; Zendler, C.; Zenin, A.V.; Zenin, O.; Zenis, T.; Zenonos, Z.; Zenz, S.; Zerwas, D.; Zevi della Porta, G.; Zhan, Z.; Zhang, H.; Zhang, J.; Zhang, Q.; Zhang, X.; Zhao, L.; Zhao, T.; Zhao, Z.; Zhemchugov, A.; Zheng, S.; Zhong, J.; Zhou, B.; Zhou, N.; Zhou, Y.; Zhu, C.G.; Zhu, H.; Zhu, Y.; Zhuang, X.; Zhuravlov, V.; Zilka, B.; Zimmermann, R.; Zimmermann, S.; Zimmermann, S.; Ziolkowski, M.; Zitoun, R.; Zivkovic, L.; Zmouchko, V.V.; Zobernig, G.; Zoccoli, A.; Zolnierowski, Y.; Zsenei, A.; zur Nedden, M.; Zutshi, V.

    2011-01-01

    Jet cross sections have been measured for the first time in proton-proton collisions at a centre-of-mass energy of 7 TeV using the ATLAS detector. The measurement uses an integrated luminosity of 17 nb-1 recorded at the Large Hadron Collider. The anti-kt algorithm is used to identify jets, with two jet resolution parameters, R = 0.4 and 0.6. The dominant uncertainty comes from the jet energy scale, which is determined to within 7% for central jets above 60 GeV transverse momentum. Inclusive single-jet differential cross sections are presented as functions of jet transverse momentum and rapidity. Dijet cross sections are presented as functions of dijet mass and the angular variable $\\chi$. The results are compared to expectations based on next-to-leading-order QCD, which agree with the data, providing a validation of the theory in a new kinematic regime.

  18. Real or symbolic domination: New revision of La Domination masculine

    Directory of Open Access Journals (Sweden)

    Tassadit Yacine

    2017-07-01

    Full Text Available This paper does a rereading of Pierre Bourdieu’s Masculine Domination (1998, from the context in which it was developed. Thus, we rely on the work carried out during the 50s in Algeria (Sociologie de l'Algérie, 1958, Esquisse d'une théorie de la pratique, 1972 and Le Sens pratique, 1980 and later in France, to show that Masculine Domination was not born spontaneously, but as a result of a long decantation enriched by field experiences and the theoretical advances of the author’s concepts. If it is true that the situation of the women described in Sociologie de l'Algérie is the result of empirical research, it is less so for Masculine Domination, whose analysis retakes the concepts forged by the social anthropologist, such as habitus and symbolic domination. In this way, this article proposes a rereading of this work through the analysis of the work that preceded it in the field.

  19. Highly dominating, highly authoritarian personalities.

    Science.gov (United States)

    Altemeyer, Bob

    2004-08-01

    The author considered the small part of the population whose members score highly on both the Social Dominance Orientation scale and the Right-Wing Authoritarianism scale. Studies of these High SDO-High RWAs, culled from samples of nearly 4000 Canadian university students and over 2600 of their parents and reported in the present article, reveal that these dominating authoritarians are among the most prejudiced persons in society. Furthermore, they seem to combine the worst elements of each kind of personality, being power-hungry, unsupportive of equality, manipulative, and amoral, as social dominators are in general, while also being religiously ethnocentric and dogmatic, as right-wing authoritarians tend to be. The author suggested that, although they are small in number, such persons can have considerable impact on society because they are well-positioned to become the leaders of prejudiced right-wing political movements.

  20. Disruptions in JET

    International Nuclear Information System (INIS)

    Wesson, J.A.; Gill, R.D.; Hugon, M.

    1989-01-01

    In JET, both high density and low-q operation are limited by disruptions. The density limit disruptions are caused initially by impurity radiation. This causes a contraction of the plasma temperature profile and leads to an MHD unstable configuration. There is evidence of magnetic island formation resulting in minor disruptions. After several minor disruptions, a major disruption with a rapid energy quench occurs. This event takes place in two stages. In the first stage there is a loss of energy from the central region. In the second stage there is a more rapid drop to a very low temperature, apparently due to a dramatic increase in impurity radiation. The final current decay takes place in the resulting cold plasma. During the growth of the MHD instability the initially rotating mode is brought to rest. This mode locking is believed to be due to an electromagnetic interaction with the vacuum vessel and external magnetic field asymmetries. The low-q disruptions are remarkable for the precision with which they occur at q ψ = 2. These disruptions do not have extended precursors or minor disruptions. The instability grows and locks rapidly. The energy quench and current decay are generally similar to those of the density limit. (author). 43 refs, 35 figs, 3 tabs

  1. Flame behavior and thermal structure of combusting plane jets with and without self-excited transverse oscillations

    Science.gov (United States)

    Huang, Rong Fung; Kivindu, Reuben Mwanza; Hsu, Ching Min

    2018-06-01

    The flame behavior and thermal structure of combusting plane jets with and without self-excited transverse oscillations were investigated experimentally. The transversely-oscillating plane jet was generated by a specially designed fluidic oscillator. Isothermal flow patterns were observed using the laser-assisted smoke flow visualization method. Meanwhile, the flame behaviour was studied using instantaneous and long-exposure photography techniques. Temperature distributions and combustion-product concentrations were measured using a fine-wire type R thermocouple and a gas analyzer, respectively. The results showed that the combusting transversely-oscillating plane jets had distributed turbulent blue flames with plaited-like edges, while the corresponding combusting non-oscillating plane jet had laminar blue-edged flames in the near field. At a high Reynolds number, the transversely-oscillating jet flames were significantly shorter and wider with shorter reaction-dominated zones than those of the non-oscillating plane jet flames. In addition, the transversely-oscillating combusting jets presented larger carbon dioxide and smaller unburned hydrocarbon concentrations, as well as portrayed characteristics of partially premixed flames. The non-oscillating combusting jets presented characteristics of diffusion flames, and the transversely-oscillating jet flame had a combustion performance superior to its non-oscillating plane jet flame counterpart. The high combustion performance of the transversely-oscillating jets was due to the enhanced entrainment, mixing, and lateral spreading of the jet flow, which were induced by the vortical flow structure generated by lateral periodic jet oscillations, as well as the high turbulence created by the breakup of the vortices.

  2. Flame behavior and thermal structure of combusting plane jets with and without self-excited transverse oscillations

    Science.gov (United States)

    Huang, Rong Fung; Kivindu, Reuben Mwanza; Hsu, Ching Min

    2017-12-01

    The flame behavior and thermal structure of combusting plane jets with and without self-excited transverse oscillations were investigated experimentally. The transversely-oscillating plane jet was generated by a specially designed fluidic oscillator. Isothermal flow patterns were observed using the laser-assisted smoke flow visualization method. Meanwhile, the flame behaviour was studied using instantaneous and long-exposure photography techniques. Temperature distributions and combustion-product concentrations were measured using a fine-wire type R thermocouple and a gas analyzer, respectively. The results showed that the combusting transversely-oscillating plane jets had distributed turbulent blue flames with plaited-like edges, while the corresponding combusting non-oscillating plane jet had laminar blue-edged flames in the near field. At a high Reynolds number, the transversely-oscillating jet flames were significantly shorter and wider with shorter reaction-dominated zones than those of the non-oscillating plane jet flames. In addition, the transversely-oscillating combusting jets presented larger carbon dioxide and smaller unburned hydrocarbon concentrations, as well as portrayed characteristics of partially premixed flames. The non-oscillating combusting jets presented characteristics of diffusion flames, and the transversely-oscillating jet flame had a combustion performance superior to its non-oscillating plane jet flame counterpart. The high combustion performance of the transversely-oscillating jets was due to the enhanced entrainment, mixing, and lateral spreading of the jet flow, which were induced by the vortical flow structure generated by lateral periodic jet oscillations, as well as the high turbulence created by the breakup of the vortices.

  3. Experimental investigation of a reacting transverse jet in a high pressure oscillating vitiated crossflow

    Science.gov (United States)

    Fugger, Christopher A.

    near a pressure node of the 1st axial combustor mode, where the dominant flowfield fluctuations are a time-varying crossflow velocity. For the non-reacting jets, the nominal jet-to-crossflow momentum flux ratio is 19. For the reacting jets, the nominal jet-to-crossflow momentum flux ratio is 6. Two cross sectional planes parallel to the jet injection wall are investigated: 1 and 2.7 jet diameters from the jet injection wall. The combustor crossflow high frequency wall mounted pressure data is given for each test case. The velocity and OH-PLIF data is presented as instantaneous snapshots, time and phase averaged flowfields, modal decompositions using Proper Orthogonal Decomposition and Dynamic Mode Decomposition, and a jet cycle analysis relative to the crossflow acoustic cycle. Analysis of the five test cases shows that the jet cross sectional velocity and OH-PLIF dynamics display a multitude of dynamics. These are often organized into shear layer dynamics and wake dynamics, but are not mutually exclusive. For large unsteady crossflow velocity oscillations at the 1st axial combustor mode, both dynamics show strong organization at the unsteady crossflow frequency. Deciphering these dynamics is complicated by the fact that the ostensible jet response to the time-varying crossflow is a time-varying jet penetration. This drives the jet toward and away from the jet injection wall. These motions are perpendicular to the laser sheet and creates significant out-of-plane motions. The amplitude of crossflow unsteadiness appears to play a role in the sharpness of the wake dynamics. For the non-reacting cases, the wake dynamics are strong and dominant spectral features in the flowfield. For the reacting cases, the wake dynamics are spectrally distinct in the lower amplitude crossflow unsteadiness case, but a large unsteady amplitude crossflow appears to suppress the spectral bands in the frequency range corresponding to wake vortex dynamics.

  4. Experimental and Numerical Study of Twin Underexpanded Impinging Jets

    Institute of Scientific and Technical Information of China (English)

    Minoru Yaga; Minoru Okano; Masumi Tamashiro; Kenyu Oyakawa

    2003-01-01

    In this paper, the dual underexpanded impinging jets are experimentally and numerically studied. The experiments were performed by measuring the unsteady and averaged wall static pressures and by visualizing density fields using schlieren method. Numerical calculations were also conducted by solving unsteady three dimensional compressible Navier-Stokes equations with Baldwin-Lomax turbulence model. The main parameters for the dual jets are the non-dimensional distance between the two nozzle centers H/D covering 1.5, 2.0, the nozzle to plate separation L/D 2.0, 3.0,4.0 and 5.0 and the pressure ratio defined by Po/Pb 1.0~6.0, where D is the diameter of each nozzle exit, Po the stagnation pressure and Pb the back pressure. It is found that the agreement between the experiments and the calculations is good. The fountain flow at the middle of the two jets is observed both in the experiments and the calculation. According to FFT analysis of the experiments for the twin jets,relatively low frequency (up to 5 kHz) is dominant for H/D =1.5, L/D =2.0 and pressure ratio Po/Pb =3.0 and 5.0,which is confirmed by the experiments.

  5. Mass spectrometric diagnosis of an atmospheric pressure helium microplasma jet

    International Nuclear Information System (INIS)

    McKay, K; Oh, J-S; Walsh, J L; Bradley, J W

    2013-01-01

    Ambient molecular beam mass spectrometry (MBMS) has been used to study how different capillary widths (530 µm and 2.4 mm) and excitation waveforms (continuous wave kHz and pulsed dc) affect the ionic composition of atmospheric pressure plasma jets. It is shown from time-averaged ion intensities that reducing the width of the jet capillary results in a significant increase in the variety of both positive and negative ions detected within the discharge. We discuss this in terms of changes in flow velocity and the onset of turbulence within the plasma plume. Changing the mode of excitation had little effect on the ionic species detected from the microplasma jet; however, there was a notable shift in dominance towards higher mass ions when operated in a continuous wave kHz mode. The temporal evolution of the ions within the microplasma jet was observed for both excitation sources, operated at 5 and 15 kHz. Positive ions were created during periods correlated with the positive and negative peaks in discharge current, while negative ions were predominantly created at times when the discharge current peak was negative. This phenomenon was independent of the driving waveform. For pulsed dc excitation, considerably fewer positive ions were created in periods related to the negative current peaks, especially at higher frequencies. We propose a simple explanation for these processes based on ideas of streamer propagation and the influence of self-induced electric fields in the plasma plume. (paper)

  6. THE EVOLUTION OF HETERGENEOUS 'CLUMPY JETS': A PARAMETER STUDY

    International Nuclear Information System (INIS)

    Yirak, Kristopher; Schroeder, Ed; Frank, Adam; Cunningham, Andrew J.

    2012-01-01

    We investigate the role discrete clumps embedded in an astrophysical jet play on the jet's morphology and line emission characteristics. By varying clumps' size, density, position, and velocity, we cover a range of parameter space motivated by observations of objects such as the Herbig-Haro object HH 34. We here extend the results presented in Yirak et al., including how analysis of individual observations may lead to spurious sinusoidal variation whose parameters vary widely over time, owing chiefly to interactions between clumps. The goodness of fits, while poor in all simulations, are best when clump-clump collisions are minimal. Our results indicate that a large velocity dispersion leads to a clump-clump collision-dominated flow which disrupts the jet beam. Finally, we present synthetic emission images of Hα and [S II] and note an excess of [S II] emission along the jet length as compared to observations. This suggests that observed beams undergo earlier processing, if they are present at all.

  7. 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.

  8. Forward Jet Vertex Tagging: A new technique for the identification and rejection of forward pileup jets

    CERN Document Server

    The ATLAS collaboration

    2015-01-01

    The suppression of pileup forward jets is crucial for a variety of physics analyses at the LHC, ranging from VBF Higgs production to SUSY searches. A novel forward pileup tagging technique that exploits the correlation between central and forward jets originating from pileup interactions is presented. Tracking and vertex information in the central $\\eta$ region is used to indirectly tag and reject forward pileup jets that are back-to-back to central pileup jets. The pileup suppression power observed in Pythia8 simulated events increases with jet \\pt and ranges between a 30\\% and 60\\% pileup jet removal for 90\\% jet selection efficiency for jets between 20 and 50 GeV.

  9. Using neural networks with jet shapes to identify b jets in e+e- interactions

    International Nuclear Information System (INIS)

    Bellantoni, L.; Conway, J.S.; Jacobsen, J.E.; Pan, Y.B.; Wu Saulan

    1991-01-01

    A feed-forward neural network trained using backpropagation was used to discriminate between b and light quark jets in e + e - → Z 0 → qanti q events. The information presented to the network consisted of 25 jet shape variables. The network successfully identified b jets in two- and three-jet events modeled using a detector simulation. The jet identification efficiency for two-jet events was 61% and the probability to call a light quark jet a b jet equal to 20%. (orig.)

  10. Forward Jets and Forward-Central Jets at CMS

    CERN Document Server

    INSPIRE-00176215

    2012-01-01

    We report on cross section measurements for inclusive forward jet production and for the simultaneous production of a forward and a central jet in sqrt{s} = 7 TeV pp-collisions. Data collected in 2010, corresponding to an integrated luminosity of 3.14 pb^{-1}, is used for the measurements. Jets in the transverse momentum range pT = 35 - 140 GeV/c are reconstructed with the anti-kT (R = 0.5) algorithm. The extended coverage of large pseudo-rapidities is provided by the Hadronic Forward calorimeter (3.2 < \\eta < 4.7), while central jets are limited to \\eta < 2.8, covered by the main detector components. The two differential cross sections are presented as a function of the jet transverse momentum. Comparisons to next-to-leading order perturbative calculations, and predictions from event generators based on different parton showering mechanisms (PYTHIA and HERWIG) and parton dynamics (CASCADE) are shown.

  11. Analysis of the variability of the North Atlantic eddy-driven jet stream in CMIP5

    Science.gov (United States)

    Iqbal, Waheed; Leung, Wai-Nang; Hannachi, Abdel

    2017-09-01

    The North Atlantic eddy-driven jet is a dominant feature of extratropical climate and its variability is associated with the large-scale changes in the surface climate of midlatitudes. Variability of this jet is analysed in a set of General Circulation Models (GCMs) from the Coupled Model Inter-comparison Project phase-5 (CMIP5) over the North Atlantic region. The CMIP5 simulations for the 20th century climate (Historical) are compared with the ERA40 reanalysis data. The jet latitude index, wind speed and jet persistence are analysed in order to evaluate 11 CMIP5 GCMs and to compare them with those from CMIP3 integrations. The phase of mean seasonal cycle of jet latitude and wind speed from historical runs of CMIP5 GCMs are comparable to ERA40. The wind speed mean seasonal cycle by CMIP5 GCMs is overestimated in winter months. A positive (negative) jet latitude anomaly in historical simulations relative to ERA40 is observed in summer (winter). The ensemble mean of jet latitude biases in historical simulations of CMIP3 and CMIP5 with respect to ERA40 are -2.43° and -1.79° respectively. Thus indicating improvements in CMIP5 in comparison to the CMIP3 GCMs. The comparison of historical and future simulations of CMIP5 under RCP4.5 and RCP8.5 for the period 2076-2099, shows positive anomalies in the jet latitude implying a poleward shifted jet. The results from the analysed models offer no specific improvements in simulating the trimodality of the eddy-driven jet.

  12. Investigations of needle-free jet injections.

    Science.gov (United States)

    Schramm-Baxter, J R; Mitragotri, S

    2004-01-01

    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, they have a low market share compared to needles possibly due to occasional pain associated with jet injection. Jets employed by the traditional jet injectors penetrate deep into the dermal and sub-dermal regions where the nerve endings are abundantly located. To eliminate the pain associated with jet injections, we propose to utilize microjets that penetrate only into the superficial region of the skin. However, the choice of appropriate jet parameters for this purpose is challenging owing to the multiplicity of factors that determine the penetration depth. 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. 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.

  13. Hand dominance in orthopaedic surgeons.

    LENUS (Irish Health Repository)

    Lui, Darren F

    2012-08-01

    Handedness is perhaps the most studied human asymmetry. Laterality is the preference shown for one side and it has been studied in many aspects of medicine. Studies have shown that some orthopaedic procedures had poorer outcomes and identified laterality as a contributing factor. We developed a questionnaire to assess laterality in orthopaedic surgery and compared this to an established scoring system. Sixty-two orthopaedic surgeons surveyed with the validated Waterloo Handedness Questionnaire (WHQ) were compared with the self developed Orthopaedic Handedness Questionnaire (OHQ). Fifty-eight were found to be right hand dominant (RHD) and 4 left hand dominant (LHD). In RHD surgeons, the average WHQ score was 44.9% and OHQ 15%. For LHD surgeons the WHQ score was 30.2% and OHQ 9.4%. This represents a significant amount of time using the non dominant hand but does not necessarily determine satisfactory or successful dexterity transferable to the operating room. Training may be required for the non dominant side.

  14. Visual dominance in olfactory memory.

    Science.gov (United States)

    Batic, N; Gabassi, P G

    1987-08-01

    The object of the present study was to verify the emergence of a 'visual dominance' effect in memory tests involving different sensory modes (sight and smell), brought about the preattentive mechanisms which select the visual sensory mode regardless of the recall task.

  15. Vector-meson dominance revisited

    Directory of Open Access Journals (Sweden)

    Terschlüsen Carla

    2012-12-01

    Full Text Available The interaction of mesons with electromagnetism is often well described by the concept of vector-meson dominance (VMD. However, there are also examples where VMD fails. A simple chiral Lagrangian for pions, rho and omega mesons is presented which can account for the respective agreement and disagreement between VMD and phenomenology in the sector of light mesons.

  16. Testing for Stochastic Dominance Efficiency

    NARCIS (Netherlands)

    G.T. Post (Thierry); O. Linton; Y-J. Whang

    2005-01-01

    textabstractWe propose a new test of the stochastic dominance efficiency of a given portfolio over a class of portfolios. We establish its null and alternative asymptotic properties, and define a method for consistently estimating critical values. We present some numerical evidence that our

  17. Holographic Jet Quenching

    Science.gov (United States)

    Ficnar, Andrej

    In this dissertation we study the phenomenon of jet quenching in quark-gluon plasma using the AdS/CFT correspondence. We start with a weakly coupled, perturbative QCD approach to energy loss, and present a Monte Carlo code for computation of the DGLV radiative energy loss of quarks and gluons at an arbitrary order in opacity. We use the code to compute the radiated gluon distribution up to n=9 order in opacity, and compare it to the thin plasma (n=1) and the multiple soft scattering (n=infinity) approximations. We furthermore show that the gluon distribution at finite opacity depends in detail on the screening mass mu and the mean free path lambda. In the next part, we turn to the studies of how heavy quarks, represented as "trailing strings" in AdS/CFT, lose energy in a strongly coupled plasma. We study how the heavy quark energy loss gets modified in a "bottom-up" non-conformal holographic model, constructed to reproduce some properties of QCD at finite temperature and constrained by fitting the lattice gauge theory results. The energy loss of heavy quarks is found to be strongly sensitive to the medium properties. We use this model to compute the nuclear modification factor RAA of charm and bottom quarks in an expanding plasma with Glauber initial conditions, and comment on the range of validity of the model. The central part of this thesis is the energy loss of light quarks in a strongly coupled plasma. Using the standard model of "falling strings", we present an analytic derivation of the stopping distance of light quarks, previously available only through numerical simulations, and also apply it to the case of Gauss-Bonnet higher derivative gravity. We then present a general formula for computing the instantaneous energy loss in non-stationary string configurations. Application of this formula to the case of falling strings reveals interesting phenomenology, including a modified Bragg-like peak at late times and an approximately linear path dependence. Based

  18. Jets from jets: re-clustering as a tool for large radius jet reconstruction and grooming at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Nachman, Benjamin; Nef, Pascal; Schwartzman, Ariel; Swiatlowski, Maximilian [SLAC National Accelerator Laboratory, Stanford University,2575 Sand Hill Rd, Menlo Park, CA 94025 (United States); Wanotayaroj, Chaowaroj [Center for High Energy Physics, University of Oregon,1371 E. 13th Ave, Eugene, OR 97403 (United States)

    2015-02-12

    Jets with a large radius R≳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 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 re-clustered large radius parameter to be optimized in the context of specific precision measurements or searches for new physics.

  19. Jets from jets: re-clustering as a tool for large radius jet reconstruction and grooming at the LHC

    International Nuclear Information System (INIS)

    Nachman, Benjamin; Nef, Pascal; Schwartzman, Ariel; Swiatlowski, Maximilian; Wanotayaroj, Chaowaroj

    2015-01-01

    Jets with a large radius R≳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 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 re-clustered large radius parameter to be optimized in the context of specific precision measurements or searches for new physics.

  20. Inclusive jet spectrum for small-radius jets

    CERN Document Server

    Dasgupta, Mrinal; Salam, Gavin P.; Soyez, Gregory

    2016-01-01

    Following on our earlier work on leading-logarithmic (LLR) resummations for the properties of jets with a small radius, R, we here examine the phenomenological considerations for the inclusive jet spectrum. We discuss how to match the NLO predictions with small-R resummation. As part of the study we propose a new, physically-inspired prescription for fixed-order predictions and their uncertainties. We investigate the R-dependent part of the next-to-next-to-leading order (NNLO) corrections, which is found to be substantial, and comment on the implications for scale choices in inclusive jet calculations. We also examine hadronisation corrections, identifying potential limitations of earlier analytical work with regards to their $p_t$-dependence. Finally we assemble these different elements in order to compare matched (N)NLO+LLR predictions to data from ALICE and ATLAS, finding improved consistency for the R-dependence of the results relative to NLO predictions.

  1. Vortex breakdown in a supersonic jet

    Science.gov (United States)

    Cutler, Andrew D.; Levey, Brian S.

    1991-01-01

    This paper reports a study of a vortex breakdown in a supersonic jet. A supersonic vortical jets were created by tangential injection and acceleration through a convergent-divergent nozzle. Vortex circulation was varied, and the nature of the flow in vortical jets was investigated using several types of flow visualization, including focusing schlieren and imaging of Rayleigh scattering from a laser light sheet. Results show that the vortical jet mixed much more rapidly with the ambient air than a comparable straight jet. When overexpanded, the vortical jet exhibited considerable unsteadiness and showed signs of vortex breakdown.

  2. Observation of jets in high transverse energy events at the CERN proton antiproton collider

    International Nuclear Information System (INIS)

    Arnison, G.; Astbury, A.; Grayer, G.; Haynes, W.J.; Nandi, A.K.; Roberts, C.; Scott, W.; Shah, T.P.; Bowcock, T.J.V.; Eisenhandler, E.; Gibson, W.R.; Honma, A.; Kalmus, P.I.P.; Keeler, R.; Salvi, G.; Thompson, G.; Cochet, C.; DeBeer, M.; Denegri, D.; Givernaud, A.; Laugier, J.P.; Leveque, A.; Locci, E.; Loret, M.; Malosse, J.J.; Rich, J.; Sass, J.; Saudraix, J.; Savoy-Navarro, A.; Spiro, M.; Dobrzynski, L.; Fontaine, G.; Geer, S.; Ghesquiere, C.; Giraud-Heraud, Y.; Kryn, D.; Mendiburu, J.P.; Orkin-Lecourtois, A.; Sajot, G.; Vrana, J.; Bacci, C.; Bernabei, R.; Ceradini, F.; Corden, M.; Dallman, D.; D'Angelo, S.; Dowell, J.D.; Edwards, M.; Eggert, K.; Ellis, N.; Erhard, P.; Faissner, H.; Frey, R.; Fruehwirth, R.; Garvey, J.; Giboni, K.L.; Gutierrez, P.; Hansl-Kozanecka, T.; Hodges, C.; Hoffmann, D.; Homer, R.J.; Karimaeki, V.; Kenyon, I.; Kernan, A.; Kinnunen, R.; Kozanecki, W.; Lehmann, H.; Leuchs, R.; McMahon, T.; Moricca, M.; Paoluzi, L.; Pimia, M.; Radermacher, E.; Ransdell, J.; Reithler, H.; Salvini, G.; Strauss, J.; Sumorok, K.; Szoncso, F.; Tscheslog, E.; Tuominiemi, J.; Wahl, H.D.; Watkins, P.; Wilson, J.

    1983-01-01

    With a segmented total absorption calorimeter of large acceptance, we have measured the total transverse energy spectrum for panti p collisions at ssup(1/2)=540 GeV up to μEsub(T)=130 GeV in the pseudo-rapidity range vertical strokeetavertical stroke 40 GeV, the fraction of events with two jets increases with μEsub(T); this event structure is dominant for μEsub(T)> 100 GeV. We measure the inclusive jet cross section up to Esub(T)(jet)=60 GeV and the two-jet mass distribution up to 120 GeV/c 2 . The measured cross sections are compatible with the predictions of hard scattering models based on QCD. (orig.)

  3. Input-output analysis of high-speed axisymmetric isothermal jet noise

    Science.gov (United States)

    Jeun, Jinah; Nichols, Joseph W.; Jovanović, Mihailo R.

    2016-04-01

    We use input-output analysis to predict and understand the aeroacoustics of high-speed isothermal turbulent jets. We consider axisymmetric linear perturbations about Reynolds-averaged Navier-Stokes solutions of ideally expanded turbulent jets with jet Mach numbers 0.6 parabolized stability equations (PSE), and this mode dominates the response. For subsonic jets, however, the singular values indicate that the contributions of sub-optimal modes to noise generation are nearly equal to that of the optimal mode, explaining why the PSE do not fully capture the far-field sound in this case. Furthermore, high-fidelity large eddy simulation (LES) is used to assess the prevalence of sub-optimal modes in the unsteady data. By projecting LES source term data onto input modes and the LES acoustic far-field onto output modes, we demonstrate that sub-optimal modes of both types are physically relevant.

  4. Influence on rewetting temperature and wetting delay during rewetting rod bundle by various radial jet models

    Energy Technology Data Exchange (ETDEWEB)

    Debbarma, Ajoy; Pandey, Krishna Murari [National Institute of Technology, Assam (India). Dept. of Mechanical Engineering

    2016-03-15

    Numerical investigation of the rewetting of single sector fuel assembly of Advanced Heavy Water Reactor (AHWR) has been carried out to exhibit the effect of coolant jet diameters (2, 3 and 4 mm) and jet directions (Model: M, X and X2). The rewetting phenomena with various jet models are compared on the basis of rewetting temperature and wetting delay. Temperature-time curve have been evaluated from rods surfaces at different circumference, radial and axial locations of rod bundle. The cooling curve indicated the presence of vapor in respected location, where it prevents the contact between the firm and fluid phases. The peak wall temperature represents as rewetting temperature. The time period observed between initial to rewetting temperature point is wetting delay. It was noted that as improved in various jet models, rewetting temperature and wetting delay reduced, which referred the coolant stipulation in the rod bundle dominant vapor formation.

  5. Influence on rewetting temperature and wetting delay during rewetting rod bundle by various radial jet models

    International Nuclear Information System (INIS)

    Debbarma, Ajoy; Pandey, Krishna Murari

    2016-01-01

    Numerical investigation of the rewetting of single sector fuel assembly of Advanced Heavy Water Reactor (AHWR) has been carried out to exhibit the effect of coolant jet diameters (2, 3 and 4 mm) and jet directions (Model: M, X and X2). The rewetting phenomena with various jet models are compared on the basis of rewetting temperature and wetting delay. Temperature-time curve have been evaluated from rods surfaces at different circumference, radial and axial locations of rod bundle. The cooling curve indicated the presence of vapor in respected location, where it prevents the contact between the firm and fluid phases. The peak wall temperature represents as rewetting temperature. The time period observed between initial to rewetting temperature point is wetting delay. It was noted that as improved in various jet models, rewetting temperature and wetting delay reduced, which referred the coolant stipulation in the rod bundle dominant vapor formation.

  6. Origins of the di-jet asymmetry in heavy ion collisions

    CERN Document Server

    Milhano, José Guilherme

    2016-01-01

    The di-jet asymmetry --- the measure of the momentum imbalance in a di-jet system --- is a key jet quenching observable. Using the event generator \\jewel we show that the di-jet asymmetry is dominated by fluctuations both in proton-proton and in heavy ion collisions. We discuss how in proton-proton collisions the asymmetry is generated through recoil and out-of-cone radiation. In heavy ion collisions two additional sources contribute to the asymmetry, namely energy loss fluctuations and differences in path length. The latter is shown to be a sub-leading effect. We discuss the implications of our results for the interpretation of this observable.

  7. Origins of the di-jet asymmetry in heavy-ion collisions

    Energy Technology Data Exchange (ETDEWEB)

    Milhano, Jose Guilherme; Zapp, Korinna Christine [Universidade de Lisboa, CENTRA, Instituto Superior Tecnico, Lisbon (Portugal); CERN, Physics Department, Theory Unit, Geneva 23 (Switzerland)

    2016-05-15

    The di-jet asymmetry - the measure of the momentum imbalance in a di-jet system - is a key jet quenching observable. Using the event generator Jewel we show that the di-jet asymmetry is dominated by fluctuations both in proton-proton and in heavy-ion collisions. We discuss how in proton-proton collisions the asymmetry is generated through recoil and out-of-cone radiation. In heavy-ion collisions two additional sources can contribute to the asymmetry, namely energy loss fluctuations and differences in path length. The latter is shown to be a sub-leading effect. We discuss the implications of our results for the interpretation of this observable. (orig.)

  8. Image processing analysis of vortex dynamics of lobed jets from three-dimensional diffusers

    International Nuclear Information System (INIS)

    Nastase, Ilinca; Meslem, Amina; El Hassan, Mouhammad

    2011-01-01

    The passive control of jet flows with the aim to enhance mixing and entrainment is of wide practical interest. Our purpose here is to develop new air diffusers for heating ventilating air conditioning systems by using lobed geometry nozzles, in order to ameliorate the users' thermal comfort. Two turbulent six-lobed air jets, issued from a lobed tubular nozzle and an innovative hemispherical lobed nozzle, were studied experimentally. It was shown that the proposed innovative concept of a lobed jet, which can be easily integrated in air diffusion devices, is very efficient regarding induction capability. A vortical dynamics analysis for the two jets is performed using a new method of image processing, namely dynamic mode decomposition. A validation of this method is also proposed suggesting that the dynamical mode decomposition (DMD) image processing method succeeds in capturing the most dominant frequencies of the flow dynamics, which in our case are related to the quite special dynamics of the Kelvin–Helmholtz vortices.

  9. Experimental results from magnetized-jet experiments executed at the Jupiter Laser Facility

    Science.gov (United States)

    Manuel, M. J.-E.; Kuranz, C. C.; Rasmus, A. M.; Klein, S. R.; MacDonald, M. J.; Trantham, M. R.; Fein, J. R.; Belancourt, P. X.; Young, R. P.; Keiter, P. A.; Drake, R. P.; Pollock, B. B.; Park, J.; Hazi, A. U.; Williams, G. J.; Chen, H.

    2015-12-01

    Recent experiments at the Jupiter Laser Facility investigated magnetization effects on collimated plasma jets. Laser-irradiated plastic-cone-targets produced collimated, millimeter-scale plasma flows as indicated by optical interferometry. Proton radiography of these jets showed no indication of strong, self-generated magnetic fields, suggesting a dominantly hydrodynamic collimating mechanism. Targets were placed in a custom-designed solenoid capable of generating field strengths up to 5 T. Proton radiographs of the well-characterized B-field, without a plasma jet, suggested an external source of trapped electrons that affects proton trajectories. The background magnetic field was aligned with the jet propagation direction, as is the case in many astrophysical systems. Optical interferometry showed that magnetization of the plasma results in disruption of the collimated flow and instead produces a hollow cavity. This result is a topic of ongoing investigation.

  10. On the dominant noise components of tactical aircraft: Laboratory to full scale

    Science.gov (United States)

    Tam, Christopher K. W.; Aubert, Allan C.; Spyropoulos, John T.; Powers, Russell W.

    2018-05-01

    This paper investigates the dominant noise components of a full-scale high performance tactical aircraft. The present study uses acoustic measurements of the exhaust jet from a single General Electric F414-400 turbofan engine installed in a Boeing F/A-18E Super Hornet aircraft operating from flight idle to maximum afterburner. The full-scale measurements are to the ANSI S12.75-2012 standard employing about 200 microphones. By comparing measured noise spectra with those from hot supersonic jets observed in the laboratory, the dominant noise components specific to the F/A-18E aircraft at different operating power levels are identified. At intermediate power, it is found that the dominant noise components of an F/A-18E aircraft are essentially the same as those of high temperature supersonic laboratory jets. However, at military and afterburner powers, there are new dominant noise components. Their characteristics are then documented and analyzed. This is followed by an investigation of their origin and noise generation mechanisms.

  11. TeV jets at ATLAS. A probe for new physics

    International Nuclear Information System (INIS)

    Ruehr, Frederik

    2009-01-01

    The production of particle jets will be the dominant process at the Large Hadron Collider (LHC), and jets will thus be the signal or de ne the environment of many analyses at the ATLAS experiment. Their precise measurement is a vital requirement for many potential discoveries of new physics beyond the Standard Model. The first part of this thesis introduces a new method to constrain and correct errors of the energy measurement of jets in the TeV regime. The emphasis is on a very high reach in transverse jet momenta even with earliest ATLAS data. This is achievable by an intercalibration utilizing the large inclusive jet production cross section. In the second part inclusive jet measurements are used to probe the validity of Quantum Chromodynamics (QCD). Several analyses are presented and their sensitivity is estimated using simulated data of an effective theory of a possible quark substructure. The search is then extended to effects of quantum gravity that could emerge at the LHC in scenarios of new physics, demonstrating that inclusive jet measurements are a powerful tool to probe QCD and a broad range of new physics models. (orig.)

  12. TeV jets at ATLAS. A probe for new physics

    Energy Technology Data Exchange (ETDEWEB)

    Ruehr, Frederik

    2009-01-29

    The production of particle jets will be the dominant process at the Large Hadron Collider (LHC), and jets will thus be the signal or de ne the environment of many analyses at the ATLAS experiment. Their precise measurement is a vital requirement for many potential discoveries of new physics beyond the Standard Model. The first part of this thesis introduces a new method to constrain and correct errors of the energy measurement of jets in the TeV regime. The emphasis is on a very high reach in transverse jet momenta even with earliest ATLAS data. This is achievable by an intercalibration utilizing the large inclusive jet production cross section. In the second part inclusive jet measurements are used to probe the validity of Quantum Chromodynamics (QCD). Several analyses are presented and their sensitivity is estimated using simulated data of an effective theory of a possible quark substructure. The search is then extended to effects of quantum gravity that could emerge at the LHC in scenarios of new physics, demonstrating that inclusive jet measurements are a powerful tool to probe QCD and a broad range of new physics models. (orig.)

  13. From nature-dominated to human-dominated environmental changes

    Science.gov (United States)

    Messerli, Bruno; Grosjean, Martin; Hofer, Thomas; Núñez, Lautaro; Pfister, Christian

    2000-01-01

    To what extent is it realistic and useful to view human history as a sequence of changes from highly vulnerable societies of hunters and gatherers through periods with less vulnerable, well buffered and highly productive agrarian-urban societies to a world with regions of extreme overpopulation and overuse of life support systems, so that vulnerability to climatic-environmental changes and extreme events is again increasing? This question cannot be fully answered in our present state of knowledge, but at least we can try to illustrate, with three case studies from different continents, time periods and ecosystems, some fundamental changes in the relationship between natural processes and human activities that occur, as we pass from a nature-dominated to a human dominated environment. 1. Early-mid Holocene: Nature dominated environment — human adaptation, mitigation, and migration. In the central Andes, the Holocene climate changed from humid (10,800-8000 BP) to extreme arid (8000-3600 BP) conditions. Over the same period, prehistoric hunting communities adopted a more sedentary pattern of resource use by settling close to the few perennial water bodies, where they began the process of domesticating camelids around 5000 BP and irrigation from about 3100 BP. 2. Historical period: An agrarian society in transition from an "enduring" to an innovative human response. Detailed documentary evidence from Western Europe may be used to reconstruct quite precisely the impacts of climatic variations on agrarian societies. The period considered spans a major transition from an apparently passive response to the vagaries of the environment during the 16th century to an active and innovative attitude from the onset of the agrarian revolution in the late 18th century through to the present day. The associated changes in technology and in agricultural practices helped to create a society better able to survive the impact of climatic extremes. 3. The present day: A human dominated

  14. Jets from jets: re-clustering as a tool for large radius jet reconstruction and grooming at the LHC

    Science.gov (United States)

    Nachman, Benjamin; Nef, Pascal; Schwartzman, Ariel; Swiatlowski, Maximilian; Wanotayaroj, Chaowaroj

    2015-02-01

    Jets with a large radius R ≳ 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 jet re-clustering. Jet re-clustering introduces an intermediate scale r groomed jets. Jet re-clustering has the benefit that no additional large-R calibration is necessary, allowing the re-clustered large radius parameter to be optimized in the context of specific precision measurements or searches for new physics.

  15. Effect of shear in the radial electric field on confinement in JET

    Energy Technology Data Exchange (ETDEWEB)

    O` Brien, D P; Balet, B; Deliyanakis, N; Cordey, J G; Stubberfield, P M [Commission of the European Communities, Abingdon (United Kingdom). JET Joint Undertaking

    1994-07-01

    The role of the radial electric field during enhanced confinement of JET discharges is studied. Results from two series of experiments are presented: beam dominated with the addition of a small amount of ICRH, and ICRH dominated discharges, showing that for high performance ICRH heated discharges which obtain the high confinement regime, there is evidence against the E x B flow stabilisation. 4 refs., 4 figs.

  16. Battery-Powered RF Pre-Ionization System for the Caltech Magnetohydrodynamically-Driven Jet Experiment: RF Discharge Properties and MHD-Driven Jet Dynamics

    Science.gov (United States)

    Chaplin, Vernon H.

    This thesis describes investigations of two classes of laboratory plasmas with rather different properties: partially ionized low pressure radiofrequency (RF) discharges, and fully ionized high density magnetohydrodynamically (MHD)-driven jets. An RF pre-ionization system was developed to enable neutral gas breakdown at lower pressures and create hotter, faster jets in the Caltech MHD-Driven Jet Experiment. The RF plasma source used a custom pulsed 3 kW 13.56 MHz RF power amplifier that was powered by AA batteries, allowing it to safely float at 4-6 kV with the cathode of the jet experiment. The argon RF discharge equilibrium and transport properties were analyzed, and novel jet dynamics were observed. Although the RF plasma source was conceived as a wave-heated helicon source, scaling measurements and numerical modeling showed that inductive coupling was the dominant energy input mechanism. A one-dimensional time-dependent fluid model was developed to quantitatively explain the expansion of the pre-ionized plasma into the jet experiment chamber. The plasma transitioned from an ionizing phase with depressed neutral emission to a recombining phase with enhanced emission during the course of the experiment, causing fast camera images to be a poor indicator of the density distribution. Under certain conditions, the total visible and infrared brightness and the downstream ion density both increased after the RF power was turned off. The time-dependent emission patterns were used for an indirect measurement of the neutral gas pressure. The low-mass jets formed with the aid of the pre-ionization system were extremely narrow and collimated near the electrodes, with peak density exceeding that of jets created without pre-ionization. The initial neutral gas distribution prior to plasma breakdown was found to be critical in determining the ultimate jet structure. The visible radius of the dense central jet column was several times narrower than the axial current channel

  17. Untangling Partnership and Domination Morality

    Directory of Open Access Journals (Sweden)

    David Loye

    2015-06-01

    Full Text Available Riane Eisler’s (1987 cultural transformation theory is an effective framework for understanding many of the constructs that shape society. This article uses Eisler’s theory to explain the formation of morality and the construction of conscience. It contrasts partnership morality and domination morality, and describes the factors that shape our tendency to embrace one or the other. The article helps us understand that we have a choice, and invites us to choose partnership morality.

  18. Sub- and supercritical jet disintegration

    Science.gov (United States)

    DeSouza, Shaun; Segal, Corin

    2017-04-01

    Shadowgraph visualization and Planar Laser Induced Fluorescence (PLIF) are applied to single orifice injection in the same facility and same fluid conditions to analyze sub- to supercritical jet disintegration and mixing. The comparison includes jet disintegration and lateral spreading angle. The results indicate that the shadowgraph data are in agreement with previous visualization studies but differ from the PLIF results that provided quantitative measurement of central jet plane density and density gradients. The study further evaluated the effect of thermodynamic conditions on droplet production and quantified droplet size and distribution. The results indicate an increase in the normalized drop diameter and a decrease in the droplet population with increasing chamber temperatures. Droplet size and distribution were found to be independent of chamber pressure.

  19. How jets get the jitters

    International Nuclear Information System (INIS)

    Zarmi, Y.

    1977-01-01

    Models in which the temporal evolution of hadronic jets and the rapidity ordering of particles within jets are correlated are discussed. Observable effects on the particle average transverse momentum (energy- and longitudinal momentum-dependence) characteristic of such models are pointed out. In particular, models in which, within jets, slow particles are produced first and fast particles come out last should exhibit the well known seagull effect, with rising, for fixed x, proportionately to the square root of the mean particle multiplicity. If, by analogy, the transverse momentum distributions of partons also exhibit such features, then we have a source of scaling violation in deep inelastic reactions that shows up at high energies rather than at low energies, and a source for an energy and Q 2 dependent in lepton pair production. (author)

  20. Electron Jet of Asymmetric Reconnection

    Science.gov (United States)

    Khotyaintsev, Yu. V.; Graham, D. B.; Norgren, C.; Eriksson, E.; Li, W.; Johlander, A.; Vaivads, A.; Andre, M.; Pritchett, P. L.; Retino, A.; hide

    2016-01-01

    We present Magnetospheric Multiscale observations of an electron-scale current sheet and electron outflow jet for asymmetric reconnection with guide field at the subsolar magnetopause. The electron jet observed within the reconnection region has an electron Mach number of 0.35 and is associated with electron agyrotropy. The jet is unstable to an electrostatic instability which generates intense waves with E(sub parallel lines) amplitudes reaching up to 300 mV/m and potentials up to 20% of the electron thermal energy. We see evidence of interaction between the waves and the electron beam, leading to quick thermalization of the beam and stabilization of the instability. The wave phase speed is comparable to the ion thermal speed, suggesting that the instability is of Buneman type, and therefore introduces electron-ion drag and leads to braking of the electron flow. Our observations demonstrate that electrostatic turbulence plays an important role in the electron-scale physics of asymmetric reconnection.

  1. Machine learning in jet physics

    CERN Multimedia

    CERN. Geneva

    2018-01-01

    High energy collider experiments produce several petabytes of data every year. Given the magnitude and complexity of the raw data, machine learning algorithms provide the best available platform to transform and analyse these data to obtain valuable insights to understand Standard Model and Beyond Standard Model theories. These collider experiments produce both quark and gluon initiated hadronic jets as the core components. Deep learning techniques enable us to classify quark/gluon jets through image recognition and help us to differentiate signals and backgrounds in Beyond Standard Model searches at LHC. We are currently working on quark/gluon jet classification and progressing in our studies to find the bias between event generators using domain adversarial neural networks (DANN). We also plan to investigate top tagging, weak supervision on mixed samples in high energy physics, utilizing transfer learning from simulated data to real experimental data.

  2. Cutting concrete with abrasion jet

    International Nuclear Information System (INIS)

    Yie, G.G.

    1982-01-01

    Fluidyne Corporation has developed a unique process and apparatus that allow selected abrasives to be introduced into high-speed waterjet to produce abrasive-entrained waterjet that has high material-cutting capabilities, which is termed by Fluidyne as the Abrasion Jet. Such Abrasion Jet has demonstrated capability in cutting hard rock and concrete at a modest pressure of less than 1360 bars (20,000 psi) and a power input of less than 45 kW (60 horsepower). Abrasion Jet cutting of concrete is characterized by its high rate of cutting, flexible operation, good cut quality, and relatively low costs. This paper presents a general description of this technology together with discussions of recent test results and how it could be applied to nuclear decontamination and decommissioning work. 8 references

  3. QCD jets from coherent states

    Energy Technology Data Exchange (ETDEWEB)

    Curci, G [European Organization for Nuclear Research, Geneva (Switzerland); Greco, M; Srivastava, Y [Istituto Nazionale di Fisica Nucleare, Frascati (Italy). Lab. Nazionale di Frascati

    1979-11-19

    A recently proposed approach to the problem of infrared and mass singularities in QCD based on the formalism of coherent states, is extended to discuss massless quark and gluon jets. The present results include all leading (ln delta) terms as well as finite terms in the energy loss epsilon, in addition to the usual ln epsilon associated with ln delta. The formulae agree with explicit perturbative calculations, whenever available. Explicit expressions for the total Ksub(T) distributions are given which take into account transverse-momentum conservation. Predictions are also made for the Q/sup 2/ dependence of the mean Ksub(T)/sup 2/ for quark and gluon jets. The jet ksub(T) distributions are extrapolated for low ksub(T) and shown to describe with good accuracy the data for eanti e..-->..qanti q..-->.. hadrons. Numerical predictions are also presented for the forthcoming PETRA, PEP and LEP machines.

  4. Three-dimensional Magnetohydrodynamical Simulations of the Morphology of Head–Tail Radio Galaxies Based on the Magnetic Tower Jet Model

    Energy Technology Data Exchange (ETDEWEB)

    Gan, Zhaoming; Yuan, Feng [Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Chinese Academy of Sciences, 80 Nandan Road, Shanghai 200030 (China); Li, Hui; Li, Shengtai, E-mail: zmgan@shao.ac.cn, E-mail: fyuan@shao.ac.cn, E-mail: hli@lanl.gov, E-mail: sli@lanl.gov [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States)

    2017-04-10

    The distinctive morphology of head–tail radio galaxies reveals strong interactions between the radio jets and their intra-cluster environment, the general consensus on the morphology origin of head–tail sources is that radio jets are bent by violent intra-cluster weather. We demonstrate in this paper that such strong interactions provide a great opportunity to study the jet properties and also the dynamics of the intra-cluster medium (ICM). By three-dimensional magnetohydrodynamical simulations, we analyze the detailed bending process of a magnetically dominated jet, based on the magnetic tower jet model. We use stratified atmospheres modulated by wind/shock to mimic the violent intra-cluster weather. Core sloshing is found to be inevitable during the wind-cluster core interaction, which induces significant shear motion and could finally drive ICM turbulence around the jet, making it difficult for the jet to survive. We perform a detailed comparison between the behavior of pure hydrodynamical jets and the magnetic tower jet and find that the jet-lobe morphology could not survive against the violent disruption in all of our pure hydrodynamical jet models. On the other hand, the head–tail morphology is well reproduced by using a magnetic tower jet model bent by wind, in which hydrodynamical instabilities are naturally suppressed and the jet could always keep its integrity under the protection of its internal magnetic fields. Finally, we also check the possibility for jet bending by shock only. We find that shock could not bend the jet significantly, and thus could not be expected to explain the observed long tails in head–tail radio galaxies.

  5. 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

  6. Properties of Supersonic Impinging Jets

    Science.gov (United States)

    Alvi, F. S.; Iyer, K. G.; Ladd, J.

    1999-11-01

    A detailed study examining the behavior of axisymmetric supersonic jets impinging on a ground plane is described. Our objective is to better understand the aeroacoustics governing this complex flowfield which commonly occurs in the vicinity of STOVL aircraft. Flow issuing through a Mach 1.5 C-D and a converging sonic nozzle is examined over a wide parametric range. For some cases a large diameter circular 'lift' plate, with an annular hole through which the jet is issued, is attached at the nozzle exit to simulate a generic airframe. The impinging jet flowfield was examined using Particle Image Velocimetry (PIV), which provides the velocity field for the entire region and shadowgraph visualization techniques. Near-field acoustic, as well as, mean and unsteady pressure measurements on the ground and lift plate surfaces were also obtained. The velocity field data, together with the surface flow measurements have resulted in a much better understanding of this flow from a fundamental standpoint while also identifying critical regions of interest for practical applications. Some of these findings include the presence of a stagnation bubble with recirculating flow; a very high speed (transonic/supersonic) radial wall jet; presence of large, spatially coherent turbulent structures in the primary jet and wall jet and high unsteady loads on the ground plane and lift plates. The results of a companion CFD investigation and its comparison to the experimental data will also be presented. Very good agreement has been found between the computational and experimental results thus providing confidence in the development of computational tools for the study of such flows.

  7. Turbulence suppression by E x B shear in JET optimized shear pulses

    International Nuclear Information System (INIS)

    Beer, M.A.; Budny, R.V.; Challis, C.D.; Conway, G.

    2000-01-01

    The authors calculate microinstability growth rates in JET optimized shear plasmas with a comprehensive gyrofluid model, including sheared E x B flows, trapped electrons, and all dominant ion species in realistic magnetic geometry. They find good correlation between E x B shear suppression of microinstabilities and both the formation and collapse of the internal transport barrier

  8. A numerical study of a supercritical fluid jet

    International Nuclear Information System (INIS)

    Sierra-Pallares, J.; Garcia-Serna, J.; Cocero, M.J.; Parra-Santos, M.T.; Castro-Ruiz, F.

    2009-01-01

    This study affords the numerical solution of the mixing of a submerged turbulent jet under supercritical conditions and near-critical conditions. Turbulence plays a very important role in the behaviour of chemical engineering equipment. An accurate prediction of the turbulence at supercritical conditions with low computational cost is crucial in designing new processes such as reactions in supercritical media, high pressure separation processes, nanomaterials processing and heterogeneous catalysis. At high-pressure, the flow cannot be modelled accurately using the ideal-gas assumption. Therefore, the real gas models must be used in order to solve accurately the fluid flow and heat transfer problems where the working fluid behaviour deviate seriously from the ideal-gas assumption. The jet structure has three parts clearly distinguished: the injection, the transition and the fully developed jet. Once the flow is dominated by the turbulent eddies of the shear layer, the flow is fully developed and the radial profiles match a similarity profile. This work reports the state of the project that is not completed and is being processed now. This work is devoted to establish the distance downstream from the injector where the jet become self-preserving and the shape of the similarity profiles. This system is of interest in the design of supercritical reactor inlets, where two streams should be mixed in the shortest length, or mixing conditions strongly affect the behaviour of the processes. The numerical results have been validated with experimental measurements made in the jet mixing region. The radial profiles for average velocity, density and temperature are analyzed. The parameters of the profile that match better the numerical results are summarized in Table 1. The density requires a lower value of n than these for velocity and temperature, which reflect smoother profiles. These conclusions are in good agreement with the results from Oschwald and Schik. (author)

  9. One-dimensional reduction of viscous jets. I. Theory

    Science.gov (United States)

    Pitrou, Cyril

    2018-04-01

    We build a general formalism to describe thin viscous jets as one-dimensional objects with an internal structure. We present in full generality the steps needed to describe the viscous jets around their central line, and we argue that the Taylor expansion of all fields around that line is conveniently expressed in terms of symmetric trace-free tensors living in the two dimensions of the fiber sections. We recover the standard results of axisymmetric jets and we report the first and second corrections to the lowest order description, also allowing for a rotational component around the axis of symmetry. When applied to generally curved fibers, the lowest order description corresponds to a viscous string model whose sections are circular. However, when including the first corrections, we find that curved jets generically develop elliptic sections. Several subtle effects imply that the first corrections cannot be described by a rod model since it amounts to selectively discard some corrections. However, in a fast rotating frame, we find that the dominant effects induced by inertial and Coriolis forces should be correctly described by rod models. For completeness, we also recover the constitutive relations for forces and torques in rod models and exhibit a missing term in the lowest order expression of viscous torque. Given that our method is based on tensors, the complexity of all computations has been beaten down by using an appropriate tensor algebra package such as xAct, allowing us to obtain a one-dimensional description of curved viscous jets with all the first order corrections consistently included. Finally, we find a description for straight fibers with elliptic sections as a special case of these results, and recover that ellipticity is dynamically damped by surface tension. An application to toroidal viscous fibers is presented in the companion paper [Pitrou, Phys. Rev. E 97, 043116 (2018), 10.1103/PhysRevE.97.043116].

  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. Identifying Jets Using Artifical Neural Networks

    Science.gov (United States)

    Rosand, Benjamin; Caines, Helen; Checa, Sofia

    2017-09-01

    We investigate particle jet interactions with the Quark Gluon Plasma (QGP) using artificial neural networks modeled on those used in computer image recognition. We create jet images by binning jet particles into pixels and preprocessing every image. We analyzed the jets with a Multi-layered maxout network and a convolutional network. We demonstrate each network's effectiveness in differentiating simulated quenched jets from unquenched jets, and we investigate the method that the network uses to discriminate among different quenched jet simulations. Finally, we develop a greater understanding of the physics behind quenched jets by investigating what the network learnt as well as its effectiveness in differentiating samples. Yale College Freshman Summer Research Fellowship in the Sciences and Engineering.

  12. The time development of QCD jets

    International Nuclear Information System (INIS)

    Caneschi, L.

    1979-01-01

    The time development of jets in perturbative QCD is studied. In spite of the fact that the total time for the jet to develop increases indefinitely with increasing energy, quark antiquark pairs remain unscreened only an infinitesimal time. (author)

  13. 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.

  14. Calculations of slurry pump jet impingement loads

    International Nuclear Information System (INIS)

    Wu, T.T.

    1996-01-01

    This paper presents a methodology to calculate the impingement load in the region of a submerged turbulent jet where a potential core exits and the jet is not fully developed. The profile of the jet flow velocities is represented by a piece-wise linear function which satisfies the conservation of momentum flux of the jet flow. The adequacy of the of the predicted jet expansion is further verified by considering the continuity of the jet flow from the region of potential core to the fully developed region. The jet impingement load can be calculated either as a direct impingement force or a drag force using the jet velocity field determined by the methodology presented

  15. Statistical analysis of JET disruptions

    International Nuclear Information System (INIS)

    Tanga, A.; Johnson, M.F.

    1991-07-01

    In the operation of JET and of any tokamak many discharges are terminated by a major disruption. The disruptive termination of a discharge is usually an unwanted event which may cause damage to the structure of the vessel. In a reactor disruptions are potentially a very serious problem, hence the importance of studying them and devising methods to avoid disruptions. Statistical information has been collected about the disruptions which have occurred at JET over a long span of operations. The analysis is focused on the operational aspects of the disruptions rather than on the underlining physics. (Author)

  16. Pneumatic pellet injector for JET

    International Nuclear Information System (INIS)

    Andelfinger, C.; Buechl, K.; Jacobi, D.; Sandmann, W.; Schiedeck, J.; Schilling, H.B.; Weber, G.

    1983-07-01

    Pellet injection is a useful tool for plasma diagnostics of tokamaks. Pellets can be applied for investigation of particle, energy and impurity transport, fueling efficiency and magnetic surfaces. Design, operation and control of a single shot pneumatic pellet gun is described in detail including all supplies, the vacuum system and the diagnostics of the pellet. The arrangement of this injector in the torus hall and the interfaces to the JET system and CODAS are considered. A guide tube system for pellet injection is discussed but it will not be recommended for JET. (orig.)

  17. CYTOGENETIC STUDIES IN MICE TREATED WITH THE JET FUELS, JET-A AND JP-8

    Science.gov (United States)

    Cytogenetic studies in mice treated with the jet fuels, Jet-A and JP-8AbstractThe genotoxic potential of the jet fuels, Jet-A and JP-8, were examined in mice treated on the skin with a single dose of 240 ug/mouse. Peripheral blood smears were prepared at the start of the ...

  18. Rebounding of a shaped-charge jet

    Science.gov (United States)

    Proskuryakov, E. V.; Sorokin, M. V.; Fomin, V. M.

    2007-09-01

    The phenomenon of rebounding of a shaped-charge jet from the armour surface with small angles between the jet axis and the target surface is considered. Rebounding angles as a function of jet velocity are obtained in experiments for a copper shaped-charge jet. An engineering calculation technique is developed. The results calculated with the use of this technique are in reasonable agreement with experimental data.

  19. Jets in relativistic heavy ion collisions

    International Nuclear Information System (INIS)

    Wang, Xin-Nian; Gyulassy, M.

    1990-09-01

    Several aspects of hard and semihard QCD jets in relativistic heavy ion collisions are discussed, including multiproduction of minijets and the interaction of a jet with dense nuclear matter. The reduction of jet quenching effect in deconfined phase of nuclear matter is speculated to provide a signature of the formation of quark gluon plasma. HIJING Monte Carlo program which can simulate events of jets production and quenching in heavy ion collisions is briefly described. 35 refs., 13 figs

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

    Science.gov (United States)

    Buskulic, D.; Casper, D.; de Bonis, I.; Decamp, D.; Ghez, P.; Goy, C.; Lees, J.-P.; Lucotte, A.; Minard, M.-N.; Odier, P.; Pietrzyk, B.; Chmeissani, M.; Crespo, J. M.; Efthymiopoulos, I.; Fernandez, E.; Fernandez-Bosman, M.; Garrido, Ll.; Juste, A.; Martinez, M.; Orteu, S.; Pacheco, A.; Padilla, C.; Palla, F.; Pascual, A.; Perlas, J. A.; Riu, I.; Sanchez, F.; Teubert, F.; Colaleo, A.; Creanza, D.; de Palma, M.; Farilla, A.; Gelao, G.; Girone, M.; Iaselli, G.; 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, R. W.; Frank, M.; Hagelberg, R.; Harvey, J.; Jacobsen, R.; Janot, P.; Jost, B.; Kneringer, E.; Knobloch, J.; Lehraus, I.; Martin, E. B.; Mato, P.; Minten, A.; Miquel, R.; Mir, Ll. M.; Moneta, L.; Oest, T.; Palazzi, P.; Pater, J. R.; Pusztaszeri, J.-F.; Ranjard, F.; Rensing, P.; Rolandi, L.; Schlatter, D.; Schmelling, M.; Schneider, O.; Tejessy, W.; Tomalin, I. R.; Venturi, A.; Wachsmuth, H.; Wildish, T.; Witzeling, W.; Wotschack, J.; Ajaltouni, Z.; 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, T.; Hansen, J. B.; Hansen, J. D.; Hansen, J. R.; Hansen, P. H.; Nilsson, B. S.; Wäänänen, A.; Kyriakis, A.; Markou, C.; Simopoulou, E.; Siotis, I.; Vayaki, A.; Zachariadou, K.; Blondel, A.; Bonneaud, G.; Brient, J. C.; Bourdon, P.; Rougé, A.; Rumpf, M.; Tanaka, R.; Valassi, A.; Verderi, M.; Videau, H.; Candlin, D. J.; Parsons, M. I.; Focardi, E.; Parrini, G.; Corden, M.; Delfino, M.; Georgiopoulos, C.; 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.; Pepe-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, D. M.; Cameron, W.; Colling, D. J.; Dornan, P. 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, T.; 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, J. J.; Bencheikh, A. M.; Benchouk, C.; Bonissent, A.; Bujosa, G.; Calvet, D.; Carr, J.; Diaconu, C.; Etienne, F.; Konstantinidis, N.; Nicod, D.; Payre, P.; Rousseau, D.; Talby, M.; Sadouki, A.; Thulasidas, M.; Trabelsi, K.; Abt, I.; Assmann, R.; Bauer, C.; Blum, W.; Brown, D.; Dietl, H.; Dydak, F.; Ganis, G.; Gotzhein, C.; Jakobs, K.; Kroha, H.; Lütjens, G.; Lutz, G.; Männer, W.; Moser, H.-G.; Richter, R.; Rosado-Schlosser, A.; Schael, S.; Settles, R.; Seywerd, H.; Denis, R. St.; Wiedenmann, W.; Wolf, G.; Boucrot, J.; Callot, O.; Cordier, A.; Davier, M.; Duflot, L.; Grivaz, J.-F.; Heusse, Ph.; Jacquet, M.; Kim, D. W.; Le Diberder, F.; Lefrançois, J.; Lutz, A.-M.; Nikolic, I.; 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, J.; Tenchini, R.; 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-Toeller, J. H.; Botterill, D. 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, W.; Lançon, E.; Lemaire, M. C.; Locci, E.; Marx, B.; Perez, 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.; Combley, F.; Koksal, A.; Letho, M.; Newton, W. M.; Rankin, C.; Reeve, J.; Thompson, L. F.; Böhrer, A.; Brandt, S.; Cowan, G.; Feigl, E.; Grupen, C.; Lutters, G.; Minguet-Rodriguez, J.; 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.; Wasserbaech, S.; 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. D.; Walsh, A. M.; Wu, Sau Lan; Wu, X.; Yamartino, J. M.; Zheng, M.; Zobernig, G.; Aleph Collaboration

    1996-02-01

    Quark and gluon jets with the same energy, 24 GeV, 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 a track impact parameter method. 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 presented which shows that the corresponding differences between gluon and b jets are significantly smaller. In a statistically limited comparison the multiplicity in c jets was found to be comparable with that observed for the jets of mixed quark flavour.

  1. Identifying a new particle with jet substructures

    International Nuclear Information System (INIS)

    Han, Chengcheng; Kim, Doojin; Kim, Minho; Postech, Pohang

    2017-01-01

    Here, we investigate a potential of determining properties of a new heavy resonance of mass O(1)TeV which decays to collimated jets via heavy Standard Model intermediary states, exploiting jet substructure techniques. Employing the Z gauge boson as a concrete example for the intermediary state, we utilize a "merged jet" defined by a large jet size to capture the two quarks from its decay. The use of the merged jet bene ts the identification of a Z-induced jet as a single, reconstructed object without any combinatorial ambiguity. We also find that jet substructure procedures may enhance features in some kinematic observables formed with subjet four-momenta extracted from a merged jet. This observation motivates us to feed subjet momenta into the matrix elements associated with plausible hypotheses on the nature of the heavy resonance, which are further processed to construct a matrix element method (MEM)-based observable. For both moderately and highly boosted Z bosons, we demonstrate that the MEM in combination with jet substructure techniques can be a very powerful tool for identifying its physical properties. Finally, we discuss effects from choosing different jet sizes for merged jets and jet-grooming parameters upon the MEM analyses.

  2. Jet physics at CDF Run II

    Energy Technology Data Exchange (ETDEWEB)

    Safonov, A.; /UC, Davis

    2004-12-01

    The latest results on jet physics at CDF are presented and discussed. Particular attention is paid to studies of the inclusive jet cross section using 177 pb{sup -1} of Run II data. Also discussed is a study of gluon and quark jet fragmentation.

  3. Whitby Jet Jewels in the Victorian Age

    OpenAIRE

    Mendonça de Carvalho, Luís; Fernandes, Francisca Maria; Nunes, Maria de Fatima; Brigola, João

    2013-01-01

    Abstract. During the middle nineteenth century, jet obtained from Whitby (England) was sought after due to its dark black color and hardness. This fossilized plant material was used in mourning jewelry, and Whitby hard jet was regarded among the best for carving and bead making. Jet fashion was connected with Queen Victoria, whose long mourning period lasted for almost forty years.

  4. Turbulent Buoyant Jets in Flowing Ambients

    DEFF Research Database (Denmark)

    Chen, Hai-Bo; Larsen, Torben; Petersen, Ole

    1991-01-01

    The mean behaviour of horizontal turbulent buoyant jets in co-flowing currents is investigated experimentally and numerically, in terms of jet trajectory, dilution and centerline density deficit and velocity decay. It is demonstrated in the paper that the laboratory data on the jet trajectory and...

  5. 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.

  6. Rapidity gaps between jets at D OE

    International Nuclear Information System (INIS)

    Abachi, S.

    1996-07-01

    We present studies of jet production via color-singlet events with low particle multiplicity between the jets. A preliminary study of the multiplicity in other regions of the color singlet events and the dependence of color-singlet exchange on jet transverse energy is also presented

  7. Searching for Jets in Heavy Ion Collisions

    International Nuclear Information System (INIS)

    Salur, Sevil

    2008-01-01

    Jet quenching measurements using leading particles and their correlations suffer from known biases, which can be removed via direct reconstruction of jets in central heavy ion collisions. In this talk, we discuss several modern jet reconstruction algorithms and background subtraction techniques that are appropriate to heavy ion collisions

  8. MOJAVE. XII. ACCELERATION AND COLLIMATION OF BLAZAR JETS ON PARSEC SCALES

    Energy Technology Data Exchange (ETDEWEB)

    Homan, D. C. [Department of Physics, Denison University, Granville, OH 43023 (United States); Lister, M. L.; Richards, J. L. [Department of Physics, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907 (United States); Kovalev, Y. Y. [Astro Space Center of Lebedev Physical Institute, Profsoyuznaya 84/32, 117997 Moscow (Russian Federation); Pushkarev, A. B.; Savolainen, T.; Ros, E. [Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, D-53121 Bonn (Germany); Kellermann, K. I., E-mail: homand@denison.edu [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22903 (United States)

    2015-01-10

    We report on the acceleration properties of 329 features in 95 blazar jets from the MOJAVE Very Long Baseline Array program. Nearly half the features and three-quarters of the jets show significant changes in speed and/or direction. In general, apparent speed changes are distinctly larger than changes in direction, indicating that changes in the Lorentz factors of jet features dominate the observed speed changes rather than bends along the line of sight. Observed accelerations tend to increase the speed of features near the jet base, ≲ 10-20 pc projected, and decrease their speed at longer distances. The range of apparent speeds at a fixed distance in an individual jet can span a factor of a few, indicating that shock properties and geometry may influence the apparent motions; however, we suggest that the broad trend of jet features increasing their speed near the origin is due to an overall acceleration of the jet flow out to deprojected distances of the order of 10{sup 2} pc, beyond which the flow begins to decelerate or remains nearly constant in speed. We estimate intrinsic rates of change of the Lorentz factors in the galaxy frame of the order of Γ-dot /Γ≃10{sup −3} to 10{sup –2} yr{sup –1}, which can lead to total Lorentz factor changes of a factor of a few on the length scales observed here. Finally, we also find evidence for jet collimation at projected distances of ≲ 10 pc in the form of the non-radial motion and bending accelerations that tend to better align features with the inner jet.

  9. Dominant inheritance of cerebral gigantism.

    Science.gov (United States)

    Zonana, J; Sotos, J F; Romshe, C A; Fisher, D A; Elders, M J; Rimoin, D L

    1977-08-01

    Cerebral gigantism is a syndrome consisting of characteristic dysmorphic features, accelerated growth in early childhood, and variable degrees of mental retardation. Its etiology and pathogenesis have not been defined. Three families are presented with multiple affected members. The vertical transmission of the trait and equal expression in both sexes in these families indicates a genetic etiology with a dominant pattern of inheritance, probably autosomal. As in previously reported cases, extensive endocrine evaluation failed to define the pathogenesis of the accelerated growth present in this disorder.

  10. Ergodic averages via dominating processes

    DEFF Research Database (Denmark)

    Møller, Jesper; Mengersen, Kerrie

    2006-01-01

    We show how the mean of a monotone function (defined on a state space equipped with a partial ordering) can be estimated, using ergodic averages calculated from upper and lower dominating processes of a stationary irreducible Markov chain. In particular, we do not need to simulate the stationary...... Markov chain and we eliminate the problem of whether an appropriate burn-in is determined or not. Moreover, when a central limit theorem applies, we show how confidence intervals for the mean can be estimated by bounding the asymptotic variance of the ergodic average based on the equilibrium chain....

  11. Virtual MHD Jets on Grids

    DEFF Research Database (Denmark)

    Lery, Thibaut; Combet, Céline; Murphy, G C

    2005-01-01

    As network performance has outpaced computational power and storage capacity, a new paradigm has evolved to enable the sharing of geographically distributed resources. This paradigm is known as Grid computing and aims to offer access to distributed resource irrespective of their physical location...... the first jet simulations and their corresponding models that could help to understand results from laboratory experiments....

  12. Disintegration of a Liquid Jet

    Science.gov (United States)

    Haenlein, A

    1932-01-01

    This report presents an experimental determination of the process of disintegration and atomization in its simplest form, and the influence of the physical properties of the liquid to be atomized on the disintegration of the jet. Particular attention was paid to the investigation of the process of atomization.

  13. An overview of JET results

    International Nuclear Information System (INIS)

    Adams, J.M.; Alladio, F.; Altmann, H.

    1989-01-01

    An overview is given of experimental results obtained on JET during 1988, and in particular of results at high total power input into plasmas with various configurations. An account is given of the various interpretations of these results and some of the difficulties encountered are related. The progress is summarised in terms of the projected D-T performance. (author)

  14. JET and COMPASS asymmetrical disruptions

    Czech Academy of Sciences Publication Activity Database

    Gerasimov, S.N.; Abreu, P.; Baruzzo, M.; Drozdov, V.; Dvornova, A.; Havlíček, Josef; Hender, T.C.; Hronová-Bilyková, Olena; Kruezi, U.; Li, X.; Markovič, Tomáš; Pánek, Radomír; Rubinacci, G.; Tsalas, M.; Ventre, S.; Villone, F.; Zakharov, L.E.

    2015-01-01

    Roč. 55, č. 11 (2015), s. 113006-113006 ISSN 0029-5515 R&D Projects: GA MŠk(CZ) LM2011021 Institutional support: RVO:61389021 Keywords : tokamak * asymmetrical disruption * JET * COMPASS Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 4.040, year: 2015

  15. Jet Production at the Tevatron

    International Nuclear Information System (INIS)

    Nang, F.

    1997-06-01

    Inclusive jet cross section and dijet angular distribution results from the CDF and D0 collaborations are presented. The possibility that compositeness might be evident at high transverse energies is explored by both experiments. Using the angular distributions, the CDF analysis excludes at the 95% CL regions with Λ + - + < 2.0 TeV for the same model

  16. Soft drop jet mass measurement

    CERN Document Server

    Roloff, Jennifer Kathryn; The ATLAS collaboration

    2018-01-01

    Calculations of jet substructure observables that are accurate beyond leading-logarithm accuracy have recently become available. Such observables are significant not only for probing the collinear regime of QCD that is largely unexplored at a hadron collider, but also for improving the understanding of jet substructure properties that are used in many studies at the Large Hadron Collider. This poster documents a measurement of the first jet substructure quantity at a hadron collider to be calculated at next-to-next-to-leading-logarithm accuracy. The normalized, differential cross-section is measured as a function of log( ρ^2), where ρ is the ratio of the soft-drop mass to the ungroomed jet transverse momentum. This quantity is measured in dijet events from 32.9 ifb of sqrt(s) = 13 TeV proton-proton collisions recorded by the ATLAS detector. The data are unfolded to correct for detector effects and compared to precise QCD calculations and leading-logarithm particle-level Monte Carlo simulations.

  17. The JET vacuum interspace system

    International Nuclear Information System (INIS)

    Orchard, J.; Scales, S.

    1999-01-01

    In the past JET has suffered from a number of vacuum leaks on components such as bellows, windows and feedthroughs due, in part, to the adverse conditions, including high mechanical forces, which may prevail during plasma operation. Therefore before the recent Tritium experiments on JET it was deemed prudent to manufacture and install items with a secondary containment or interspace in order to minimise the effect of failure of the primary vacuum barrier on both the leak integrity of the machine and the outcome of the experiments. This paper describes the philosophy, logistics, method and implementation of an integrated connection and monitoring system on the 330 interspaces currently in position on the JET machine. Using the JET leak database comparisons are drawn of leak failure rates of the components allied to the number of operational hours, prior to the system being present and after installation and commissioning, and the case of detection compared to the previous situation. An argument is also presented on the feasibility and adaptability of this system to any large complex machine and the benefits to be obtained in reduction of leaks and operational down time. (author)

  18. Misaligned Accretion and Jet Production

    Science.gov (United States)

    King, Andrew; Nixon, Chris

    2018-04-01

    Disk accretion onto a black hole is often misaligned from its spin axis. If the disk maintains a significant magnetic field normal to its local plane, we show that dipole radiation from Lense–Thirring precessing disk annuli can extract a significant fraction of the accretion energy, sharply peaked toward small disk radii R (as R ‑17/2 for fields with constant equipartition ratio). This low-frequency emission is immediately absorbed by surrounding matter or refracted toward the regions of lowest density. The resultant mechanical pressure, dipole angular pattern, and much lower matter density toward the rotational poles create a strong tendency to drive jets along the black hole spin axis, similar to the spin-axis jets of radio pulsars, also strong dipole emitters. The coherent primary emission may explain the high brightness temperatures seen in jets. The intrinsic disk emission is modulated at Lense–Thirring frequencies near the inner edge, providing a physical mechanism for low-frequency quasi-periodic oscillations (QPOs). Dipole emission requires nonzero hole spin, but uses only disk accretion energy. No spin energy is extracted, unlike the Blandford–Znajek process. Magnetohydrodynamic/general-relativistic magnetohydrodynamic (MHD/GRMHD) formulations do not directly give radiation fields, but can be checked post-process for dipole emission and therefore self-consistency, given sufficient resolution. Jets driven by dipole radiation should be more common in active galactic nuclei (AGN) than in X-ray binaries, and in low accretion-rate states than high, agreeing with observation. In non-black hole accretion, misaligned disk annuli precess because of the accretor’s mass quadrupole moment, similarly producing jets and QPOs.

  19. Impurity transport in internal transport barrier discharges on JET

    International Nuclear Information System (INIS)

    Dux, R.; Giroud, C.; Zastrow, K.-D.

    2004-01-01

    Impurity behaviour in JET internal transport barrier (ITB) discharges with reversed shear has been investigated. Metallic impurities accumulate in cases with too strong peaking of the main ion density profile. The accumulation is due to inwardly directed drift velocities inside the ITB radius. The strength of the impurity peaking increases with the impurity charge and is low for the low-Z elements C and Ne. Transport calculations show that the observed behaviour is consistent with dominant neoclassical impurity transport inside the ITB. In some cases, MHD events in the core flatten the radial profile of the metallic impurity. (author)

  20. 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.

  1. 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.

  2. RADIATION MECHANISM AND JET COMPOSITION OF GAMMA-RAY BURSTS AND GeV-TeV-SELECTED RADIO-LOUD ACTIVE GALACTIC NUCLEI

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Jin; Lu Ye; Zhang Shuangnan [National Astronomical Observatories, Chinese Academy of Sciences, Beijing 100012 (China); Liang Enwei; Sun Xiaona [Department of Physics and GXU-NAOC Center for Astrophysics and Space Sciences, Guangxi University, Nanning 530004 (China); Zhang Bing, E-mail: lew@gxu.edu.cn [Department of Physics and Astronomy, University of Nevada, Las Vegas, NV 89154 (United States)

    2013-09-01

    Gamma-ray bursts (GRBs) and GeV-TeV-selected radio-loud active galactic nuclei (AGNs) are compared based on our systematic modeling of the observed spectral energy distributions of a sample of AGNs with a single-zone leptonic model. We show that the correlation between the jet power (P{sub jet}) and the prompt gamma-ray luminosity (L{sub jet}) of GRBs is consistent, within the uncertainties, with the correlation between jet power and the synchrotron peak luminosity (L{sub s,jet}) of flat spectrum radio quasars (FSRQs). Their radiation efficiencies ({epsilon}) are also comparable (>10% for most sources), which increase with the bolometric jet luminosity (L{sub bol,jet}) for FSRQs and with the L{sub jet} for GRBs with similar power-law indices. BL Lac objects (BL Lacs) do not follow the P{sub jet}-L{sub s,jet} relation of FSRQs. They have lower {epsilon} and L{sub bol,jet} values than FSRQs, and a tentative L{sub bol,jet}-{epsilon} relation is also found, with a power-law index different from that of the FSRQs. The magnetization parameters ({sigma}) of FSRQs are on average larger than that of BL Lacs. They are anti-correlated with {epsilon} for the FSRQs, but positively correlated with {epsilon} for the BL Lacs. GeV narrow-line Seyfert 1 galaxies potentially share similar properties with FSRQs. Based on the analogy between GRBs and FSRQs, we suggest that the prompt gamma-ray emission of GRBs is likely produced by the synchrotron process in a magnetized jet with high radiation efficiency, similar to FSRQs. The jets of BL Lacs, on the other hand, are less efficient and are likely more matter-dominated.

  3. Laser Boost of a Small Interstellar Ram Jet to Obtain Operational Velocity. Implications for the DM Rocket/Ram Jet Model

    Science.gov (United States)

    Walcott Beckwith, Andrew

    2010-05-01

    In other conference research papers, Beckwith obtained a maximum DM mass/energy value of up to 5 TeV, as opposed to 400 GeV for DM, which may mean more convertible power for a dark matter ram jet. The consequences are from assuming that axions are CDM, and KK gravitons are for WDM, then ρWarm-Dark-Matter would dominate not only structure formation in early universe formation, but would also influence the viability of the DM ram jet applications for interstellar travel. The increase in convertible DM mass makes the ram jet a conceivable option. This paper in addition to describing the scientific issues leading to that 5 TeV mass for DM also what are necessary and sufficient laser boost systems which would permit a ram net to become operational.

  4. Jet Energy Scale Uncertainties in ATLAS

    CERN Document Server

    Barillari, T; The ATLAS collaboration

    2012-01-01

    About one year after the first proton-proton collisions at a centre of mass energy of $sqrt(s) = 7,TeV$, the ATLAS experiment has achieved an accuracy of the jet energy measurement between $2-4%$ for jet transverse momenta from $20,GeV$ to $2,TeV$ in the pseudorapidity range up to $4.5$. The jet energy scale uncertainty is derived from in-situ single hadron response measurement along with systematic variations in the Monte Carlo simulation. In addition, the transverse momentum balance between a central and a forward jet in events with only two jets at high transverse momentum is used to set the jet energy uncertainty in the forward region. The obtained uncertainty is confirmed by in-situ measurements exploiting the transverse momentum balance between a jet and a well measured reference object like the photon transverse momentum in photon-jet events. Jets in the TeV-energy regime were tested using a system of well calibrated jets at low transverse momenta against a high-pt jet. Preliminary results from the 201...

  5. Jet Energy Scale Uncertainties in ATLAS

    International Nuclear Information System (INIS)

    Barillari, Teresa

    2012-01-01

    The first proton-proton collisions at a centre of mass energy of √s = 7TeV have been used by the ATLAS experiment to achieve an accuracy of the jet energy measurement between 2% and 4% for jets transverse momenta between 20 GeV and 2TeV and in the absolute pseudorapidity range up to 4.5. The jet energy scale uncertainty is derived from measurements in situ of the calorimeter single response to hadrons together with systematic variations in the Monte Carlo simulation. The transverse momentum balance between a central and a forward jet in events with two high transverse momenta jets is used to set the jet energy uncertainty in the forward region. The obtained uncertainty is confirmed by in-situ measurements. Jets in the TeV energy range have been tested using a system of well calibrated jets at low transverse momenta against high transverse momenta jets. A further reduction of the jet energy scale uncertainty between 1% and 2% for jets transverse momenta above 30 GeV has been achieved using data from the 2011 run based on an integrated luminosity of 5 fb −1 .

  6. Numerical simulation of sand jet in water

    Energy Technology Data Exchange (ETDEWEB)

    Azimi, A.H.; Zhu, D.; Rajaratnam, N. [Alberta Univ., Edmonton, AB (Canada). Dept. of Civil and Environmental Engineering

    2008-07-01

    A numerical simulation of sand jet in water was presented. The study involved a two-phase flow using two-phase turbulent jets. A literature review was also presented, including an experiment on particle laden air jet using laser doppler velocimetry (LDV); experiments on the effect of particle size and concentration on solid-gas jets; an experimental study of solid-liquid jets using particle image velocimetry (PIV) technique where mean velocity and fluctuations were measured; and an experimental study on solid-liquid jets using the laser doppler anemometry (LDA) technique measuring both water axial and radial velocities. Other literature review results included a photographic study of sand jets in water; a comparison of many two-phase turbulent flow; and direct numerical simulation and large-eddy simulation to study the effect of particle in gas jet flow. The mathematical model and experimental setup were also included in the presentation along with simulation results for sand jets, concentration, and kinetic energy. The presentation concluded with some proposed future studies including numerical simulation of slurry jets in water and numerical simulation of slurry jets in MFT. tabs., figs.

  7. The JET multi-pellet injector launcher

    International Nuclear Information System (INIS)

    Kupschus, P.; Bailey, W.; Gadeberg, M.; Hedley, L.; Twyman, P.; Szabo, T.; Evans, D.

    1987-01-01

    Under a collaborative agreement between the Joint European Torus JET and the United States Department of Energy US DOE, JET and Oak Ridge National Laboratory (ORNL) jointly built a multi-pellet injector for fuelling and re-fuelling of the JET plasma. A three-barrel repetitive pneumatic pellet Launcher - built by ORNL - is attached to a JET pellet launcher-machine interface (in short: Pellet Interface) which is the subject of this paper. The present Launcher-Interface combination provides deuterium or hydrogen injection at moderate pellet speeds for the next two operational periods on JET. The Pellet Interface, however, takes into account the future requirements of JET. It was designed to allow the attachment of the high speed pellet launchers now under development at JET and complies with the requirements of remote handling and tritium operation. In addition, the use of tritium pellets is being considered

  8. On domination multisubdivision number of unicyclic graphs

    Directory of Open Access Journals (Sweden)

    Joanna Raczek

    2018-01-01

    Full Text Available The paper continues the interesting study of the domination subdivision number and the domination multisubdivision number. On the basis of the constructive characterization of the trees with the domination subdivision number equal to 3 given in [H. Aram, S.M. Sheikholeslami, O. Favaron, Domination subdivision number of trees, Discrete Math. 309 (2009, 622-628], we constructively characterize all connected unicyclic graphs with the domination multisubdivision number equal to 3. We end with further questions and open problems.

  9. Study of two-phase underexpanded jets by gas jet

    International Nuclear Information System (INIS)

    Uchida, Mitsunori; Someya, Satoshi; Okamoto, Koji

    2008-01-01

    When a heat exchange in a Fast Breeder Reactor cracks, a sodium-water reaction occurs. When a tube cracks, highly pressurized water or steam escapes into the surrounding liquid sodium and a sodium-water reaction occurs forming the disodium oxide. The disodium oxide caught in the steam jet strikes other tubes in the reactor. The struck disodium oxide can then cause these tubes to crack. The release of steam into the liquid sodium media is a two-phase flow involving underexpansion. In this paper qualitative measurement of the underexpanded gas jet which injected into water was carried our for the purpose of analyzing the behavior of the two-phase flow. (author)

  10. 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.

  11. La Physique des gamma-jets avec le calorimètre EMCal de l'expérience ALICE au LHC

    CERN Document Server

    Bourdaud, Guénolé

    Heavy ion collisions at LHC will produce a new state of matter : the quark-gluon plasma (QGP). Photons are not sensible to the strong interaction which dominates the nuclear medium, and hence are a valuable tool to explore QGP. Gamma-jets are rare hard processes : a photon and a parton are emitted back-to-back. The parton hadronises and produces a jet of particles. These jets are quenched due to the strong interaction of the parton with the QGP. This quenching, or more precisely the re-distribution of the energy in the jet, can be measured by the modification of the distribution of the particle energy in the jet, comparing p-p and Pb-Pb collisions (fragmentation functions or hump-backed plateau distributions). For this porpose, jet energy is needed, and can be provided precisely by gamma-jet measurement. Our goal is to use EMCal to detect a photon correlated with a jet reconstructed in ALICE tracking system. Then, the jet energy distribution are compared for p-p an Pb-Pb collisions. Gamma-jet physics is first...

  12. Rarefaction acceleration of ultrarelativistic magnetized jets in gamma-ray burst sources

    Science.gov (United States)

    Komissarov, Serguei S.; Vlahakis, Nektarios; Königl, Arieh

    2010-09-01

    When a magnetically dominated superfast-magnetosonic long/soft gamma-ray burst (GRB) jet leaves the progenitor star, the external pressure support will drop and the jet may enter the regime of ballistic expansion, during which additional magnetic acceleration becomes ineffective. However, recent numerical simulations by Tchekhovskoy et al. have suggested that the transition to this regime is accompanied by a spurt of acceleration. We confirm this finding numerically and attribute the acceleration to a sideways expansion of the jet, associated with a strong magnetosonic rarefaction wave that is driven into the jet when it loses pressure support, which induces a conversion of magnetic energy into kinetic energy of bulk motion. This mechanism, which we dub rarefaction acceleration, can only operate in a relativistic outflow because in this case the total energy can still be dominated by the magnetic component even in the superfast-magnetosonic regime. We analyse this process using the equations of relativistic magnetohydrodynamics and demonstrate that it is more efficient at converting internal energy into kinetic energy when the flow is magnetized than in a purely hydrodynamic outflow, as was found numerically by Mizuno et al. We show that, just as in the case of the magnetic acceleration of a collimating jet that is confined by an external pressure distribution - the collimation-acceleration mechanism - the rarefaction-acceleration process in a magnetized jet is a consequence of the fact that the separation between neighbouring magnetic flux surfaces increases faster than their cylindrical radius. However, whereas in the case of effective collimation-acceleration the product of the jet opening angle and its Lorentz factor does not exceed ~1, the addition of the rarefaction-acceleration mechanism makes it possible for this product to become >>1, in agreement with the inference from late-time panchromatic breaks in the afterglow light curves of long/soft GRBs.

  13. 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 .

  14. Considerations and calculations on the breakup of jets and drops of melt related to premixing

    Energy Technology Data Exchange (ETDEWEB)

    Buerger, M.; Berg, E. von; Buck, M. [Inst. fuer Kernenergetik und Energiesysteme (IKE), Univ. of Stuttgart, Pfaffenwaldring 31, 70569 Stuttgart (Germany)

    1998-01-01

    Various descriptions of jet and drop breakup are applied in premixing codes, presently. The main task is to check these descriptions over a wide range of conditions in order to assure extrapolation capabilities for the codes. Jet breakup under non-boiling conditions is relatively well described by IKEJET, based on Conte/Miles (CM) instability description and a relatively detailed stripping model, in contrast to using Kelvin/Helmholtz (KH) theory. Remaining open questions are elaborated. Especially, thick jet behavior with dominance of stripping even at small relative velocities must be distinguished from thin jets with coarse breakup. The application of IKEJET to cases with jet breakup under strong film boiling yielded significantly too little fragmentation. As a possible explanation line, multiphase effects on the wave growth and stripping are considered, due to entrainment of melt and water. Parametric checking calculations are performed with a strongly simplified approach for PREMIX and FARO experiments in order to reveal main effects and the possible physical explanation features as a basis for extended modelling. The results indicate that jet breakup may be essentially sufficient to explain the experimental behavior. Rather coalescence than further drop breakup may be expected. This is also indicated by calculations with IKE drop breakup models. (author)

  15. Laminar and turbulent nozzle-jet flows and their acoustic near-field

    International Nuclear Information System (INIS)

    Bühler, Stefan; Obrist, Dominik; Kleiser, Leonhard

    2014-01-01

    We investigate numerically the effects of nozzle-exit flow conditions on the jet-flow development and the near-field sound at a diameter-based Reynolds number of Re D = 18 100 and Mach number Ma = 0.9. Our computational setup features the inclusion of a cylindrical nozzle which allows to establish a physical nozzle-exit flow and therefore well-defined initial jet-flow conditions. Within the nozzle, the flow is modeled by a potential flow core and a laminar, transitional, or developing turbulent boundary layer. The goal is to document and to compare the effects of the different jet inflows on the jet flow development and the sound radiation. For laminar and transitional boundary layers, transition to turbulence in the jet shear layer is governed by the development of Kelvin-Helmholtz instabilities. With the turbulent nozzle boundary layer, the jet flow development is characterized by a rapid changeover to a turbulent free shear layer within about one nozzle diameter. Sound pressure levels are strongly enhanced for laminar and transitional exit conditions compared to the turbulent case. However, a frequency and frequency-wavenumber analysis of the near-field pressure indicates that the dominant sound radiation characteristics remain largely unaffected. By applying a recently developed scaling procedure, we obtain a close match of the scaled near-field sound spectra for all nozzle-exit turbulence levels and also a reasonable agreement with experimental far-field data

  16. TeV Jets at ATLAS - A Probe for New Physics

    CERN Document Server

    Rühr, Frederik

    2009-01-01

    The production of particle jets will be the dominant process at the Large Hadron Collider (LHC), and jets will thus be the signal or de ne the environment of many analyses at the ATLAS experiment. Their precise measurement is a vital requirement for many potential discoveries of new physics beyond the Standard Model. The rst part of this thesis introduces a new method to constrain and correct errors of the energy measurement of jets in the TeV regime. The emphasis is on a very high reach in transverse jet momenta even with earliest ATLAS data. This is achievable by an intercalibration utilizing the large inclusive jet production cross section. In the second part inclusive jet measurements are used to probe the validity of Quantum Chromodynamics (QCD). Several analyses are presented and their sensitivity is estimated using simulated data of an e ective theory of a possible quark substructure. The search is then extended to e ects of quantum gravity that could emerge at the LHC in scenarios of new physics, demo...

  17. Cross-Stream PIV Measurements of Jets With Internal Lobed Mixers

    Science.gov (United States)

    Bridges, James; Wernet, Mark P.

    2004-01-01

    With emphasis being placed on enhanced mixing of jet plumes for noise reduction and on predictions of jet noise based upon turbulent kinetic energy, unsteady measurements of jet plumes are a very important part of jet noise studies. Given that hot flows are of most practical interest, optical techniques such as Particle Image Velocimetry (PIV) are applicable. When the flow has strong azimuthal features, such as those generated by chevrons or lobed mixers, traditional PIV, which aligns the measurement plane parallel to the dominant flow direction is very inefficient, requiring many planes of data to be acquired and stacked up to produce the desired flow cross-sections. This paper presents PIV data acquired in a plane normal to the jet axis, directly measuring the cross-stream gradients and features of an internally mixed nozzle operating at aircraft engine flow conditions. These nozzle systems included variations in lobed mixer penetration, lobe count, lobe scalloping, and nozzle length. Several cases validating the accuracy of the PIV data are examined along with examples of its use in answering questions about the jet noise generation processes in these nozzles. Of most interest is the relationship of low frequency aft-directed noise with turbulence kinetic energy and mean velocity.

  18. The scientific success of JET

    International Nuclear Information System (INIS)

    Keilhacker, M.; Gibson, A.; Gormezano, C.; Rebut, P.H.

    2001-01-01

    The paper highlights the JET work in physics and technology during the period of the JET Joint Undertaking (1978-1999), with special emphasis on what has been learned for extrapolation to a NEXT STEP device. - Global confinement scaling has been extended to high currents and heating powers. Dimensionless scaling experiments of ELMy H mode plasmas suggest that bulk plasma transport is gyro-Bohm and predict ignition for a device with ITER-FDR parameters. Experiments in which the plasma elongation and triangularity were varied independently show a strong increase of confinement time with elongation (τ E ∼κ α 0.8±0.3 ), thus supporting a basic design principle of ITER-FEAT. With the Pellet Enhanced Performance (PEP) mode, JET has discovered the beneficial effect of reversed magnetic shear on confinement, opening the possibility of advanced tokamak scenarios. - With a three stage programme of progressively more closed divertors, JET has demonstrated the benefits of divertor closure, in particular, of high divertor neutral pressure which facilitates helium removal. It has also shown that in detached (or semidetached) radiative divertor plasmas the average power load on the target plates of a NEXT STEP device should be tolerable but, in addition, that the transient power loads during ELMs could cause problems. - In 1991 JET has demonstrated the first ever controlled production of a megawatt of fusion power. More extensive D-T experiments in 1997 (DTE1) have established new records in fusion performance: 16 MW transient fusion power with Q in =0.62 (i.e. close to breakeven, Q in =1) and 4 MW steady state fusion power with Q in =0.18 for 4 s. DTE1 has also allowed a successful test of various reactor ICRF heating schemes and a clear demonstration of alpha particle heating, consistent with classical expectations. - JET has developed and tested some of the most important technologies for a NEXT STEP and a reactor, in particular the safe handling of tritium and the

  19. Inclusive jet spectrum for small-radius jets

    Energy Technology Data Exchange (ETDEWEB)

    Dasgupta, Mrinal [Consortium for Fundamental Physics, School of Physics & Astronomy, University of Manchester,Manchester M13 9PL (United Kingdom); Dreyer, Frédéric A. [Sorbonne Universités, UPMC Univ Paris 06, UMR 7589, LPTHE,F-75005, Paris (France); CNRS, UMR 7589, LPTHE,F-75005, Paris (France); CERN, Theoretical Physics Department,CH-1211 Geneva 23 (Switzerland); Salam, Gavin P. [CERN, Theoretical Physics Department,CH-1211 Geneva 23 (Switzerland); Soyez, Gregory [IPhT, CEA Saclay, CNRS UMR 3681,F-91191 Gif-sur-Yvette (France)

    2016-06-09

    Following on our earlier work on leading-logarithmic (LL{sub R}) resummations for the properties of jets with a small radius, R, we here examine the phenomenological considerations for the inclusive jet spectrum. We discuss how to match the NLO predictions with small-R resummation. As part of the study we propose a new, physically-inspired prescription for fixed-order predictions and their uncertainties. We investigate the R-dependent part of the next-to-next-to-leading order (NNLO) corrections, which is found to be substantial, and comment on the implications for scale choices in inclusive jet calculations. We also examine hadronisation corrections, identifying potential limitations of earlier analytical work with regards to their p{sub t}-dependence. Finally we assemble these different elements in order to compare matched (N)NLO+LL{sub R} predictions to data from ALICE and ATLAS, finding improved consistency for the R-dependence of the results relative to NLO predictions.

  20. 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.

  1. Probing dark matter with active galactic nuclei jets

    International Nuclear Information System (INIS)

    Gorchtein, Mikhail; Profumo, Stefano; Ubaldi, Lorenzo

    2010-01-01

    We study the possibility of detecting a signature of particle dark matter in the spectrum of gamma-ray photons from active galactic nuclei (AGNs) resulting from the scattering of high-energy particles in the AGN jet off of dark matter particles. We consider particle dark matter models in the context of both supersymmetry and universal extra dimensions , and we present the complete lowest-order calculation for processes where a photon is emitted in dark matter-electron and/or dark matter-proton scattering, where electrons and protons belong to the AGN jet. We find that the process is dominated by a resonance whose energy is dictated by the particle spectrum in the dark matter sector (neutralino and selectron for the case of supersymmetry, Kaluza-Klein photon and electron for universal extra dimensions ). The resulting gamma-ray spectrum exhibits a very characteristic spectral feature, consisting of a sharp break to a hard power-law behavior. Although the normalization of the gamma-ray flux depends strongly on assumptions on both the AGN jet geometry, composition and particle spectrum as well as on the particle dark matter model and density distribution, we show that for realistic parameters choices, and for two prominent nearby AGNs (Centaurus A and M87), the detection of this effect is in principle possible. Finally, we compare our predictions and results with recent gamma-ray observations from the Fermi, H.E.S.S., and VERITAS telescopes.

  2. VARIABILITY IN ACTIVE GALACTIC NUCLEI FROM PROPAGATING TURBULENT RELATIVISTIC JETS

    Energy Technology Data Exchange (ETDEWEB)

    Pollack, Maxwell; Pauls, David; Wiita, Paul J., E-mail: wiitap@tcnj.edu [Department of Physics, The College of New Jersey P.O. Box 7718, Ewing, NJ 08628-0718 (United States)

    2016-03-20

    We use the Athena hydrodynamics code to model propagating two-dimensional relativistic jets as approximations to the growth of radio-loud active galactic nuclei for various input jet velocities and jet-to-ambient matter density ratios. Using results from these simulations we estimate the changing synchrotron emission by summing the fluxes from a vertical strip of zones behind the reconfinement shock, which is nearly stationary, and from which a substantial portion of the flux variability should arise. We explore a wide range of timescales by considering two light curves from each simulation; one uses a relativistic turbulence code with bulk velocities taken from our simulations as input, while the other uses the bulk velocity data to compute fluctuations caused by variations in the Doppler boosting due to changes in the direction and the speed of the flow through all zones in the strip. We then calculate power spectral densities (PSDs) from the light curves for both turbulent and bulk velocity origins for variability. The range of the power-law slopes of the PSDs for the turbulence induced variations is −1.8 to −2.3, while for the bulk velocity produced variations this range is −2.1 to −2.9; these are in agreement with most observations. When superimposed, these power spectra span a very large range in frequency (about five decades), with the turbulent fluctuations yielding most of the shorter timescale variations and the bulk flow changes dominating the longer periods.

  3. VARIABILITY IN ACTIVE GALACTIC NUCLEI FROM PROPAGATING TURBULENT RELATIVISTIC JETS

    International Nuclear Information System (INIS)

    Pollack, Maxwell; Pauls, David; Wiita, Paul J.

    2016-01-01

    We use the Athena hydrodynamics code to model propagating two-dimensional relativistic jets as approximations to the growth of radio-loud active galactic nuclei for various input jet velocities and jet-to-ambient matter density ratios. Using results from these simulations we estimate the changing synchrotron emission by summing the fluxes from a vertical strip of zones behind the reconfinement shock, which is nearly stationary, and from which a substantial portion of the flux variability should arise. We explore a wide range of timescales by considering two light curves from each simulation; one uses a relativistic turbulence code with bulk velocities taken from our simulations as input, while the other uses the bulk velocity data to compute fluctuations caused by variations in the Doppler boosting due to changes in the direction and the speed of the flow through all zones in the strip. We then calculate power spectral densities (PSDs) from the light curves for both turbulent and bulk velocity origins for variability. The range of the power-law slopes of the PSDs for the turbulence induced variations is −1.8 to −2.3, while for the bulk velocity produced variations this range is −2.1 to −2.9; these are in agreement with most observations. When superimposed, these power spectra span a very large range in frequency (about five decades), with the turbulent fluctuations yielding most of the shorter timescale variations and the bulk flow changes dominating the longer periods

  4. Particle retention during long discharges in Tore Supra and JET

    International Nuclear Information System (INIS)

    Loarer, T.; Tsitrone, E.; Brosset, C.; Bucalossi, J.; Gunn, J.; Joffrin, E.; Monier-Garbet, P.; Pegourie, B.; Thomas, P.; Lomas, P.; Ongena, J.

    2003-01-01

    The particle balances and the associated particle retentions for the long discharge experiments performed in Tore-Supra and for the L and H mode discharges carried out in JET are reported in this paper. From the reported experiments, the same particle retention behaviors are observed in Tore-Supra and JET in spite of the differences between the plasma geometry and the confinement mode (respectively limiter L-mode and divertor H-mode). A particle retention up to 70-80% of Γ(puff) for the larger gas injection has been obtained in JET. The particle retention behavior observed with the gas puff appears to be strongly dominant in the particle retention process. Indeed, no influence has been noticed from the active pumping, the saturation of the recycling area (0.4 D/C), the precedent discharges history (in terms of total 'particles retained' in the vessel) and even from the disruptions (conditioning). Also, the outgassing between discharges becomes negligible in terms of particle recovering when Γ(puff) and/or the discharge duration are increased. Finally, neither the edge localized modes (ELMs type-I or III) nor the disruptions modify the reported behaviour. For ITER, the particle retention is strictly limited and from the presented results it seems that strong gas injection should be avoided. (A.C.)

  5. Characteristics of compressed natural gas jet and jet-wall impingement using the Schlieren imaging technique

    International Nuclear Information System (INIS)

    Ismael, M A; Heikal, M R; Baharom, M B

    2013-01-01

    An experimental study was performed to investigate the compressed natural gas jet characteristics and jet-wall impingement using the Schlieren imaging technique and image processing. An injector driver was used to drive the natural gas injector and synchronized with camera triggering. A constant-volume optical chamber was designed to facilitate maximum optical access for the study of the jet macroscopic characteristics and jet-wall impingement at different injection pressures and injectors-wall distances. Measurement of the jet tip penetration and cone angle at different conditions are presented in this paper together with temporal presentation of the jet radial travel along the wall.

  6. Durability of ink jet prints

    International Nuclear Information System (INIS)

    Dobric, E; Mirkovic, I Bolanca; Bolanca, Z

    2010-01-01

    The aim of this paper is the result presentation of some optical properties research for ink jet prints after: exposing the prints to the mixed daylight and artificial light, exposing of prints to the sun-light through the glass window, and exposing of prints to outdoor conditions during the summer months. The prints obtained by piezoelectric and thermal ink jet technologies were used in the researches. The dye-based inks and the pigmented inks based on water and the low solvent inks were used. The results of these researches, except the scientific contribution in the domain of understanding and explaining the environmental conditions on the gamut size, i.e. the range of color tonality, colorimetric stability and print quality, can be used by the ink and paper manufacturers in new formulations, offer data for the printer producers for further production and evaluation of the position of their products.

  7. The engineering of JET diagnostics

    International Nuclear Information System (INIS)

    Walker, C.I.; Dillon, S.F.; Hammond, N.P.; Hancock, C.J.; Lam, N.; McCarron, E.J.; Prior, P.C.S.; Reid, J.; Sanders, S.; Tellier, X.; Tiscornia, A.J.; Whitfield, G.A.H.; Wilson, C.H.; Wilson, D.J.

    1995-01-01

    There are some 62 identifiably different diagnostic systems on JET. 22 were installed new at the last, Pumped Divertor, shutdown and a further 22 which were modified, upgraded or repositioned. This paper describes some of the engineering aspects peculiar to the renewed diagnostic systems, reviews their construction and installation and gives an overview of the design of presently installed diagnostic equipment at the Torus. Examples are considered that illustrate the breakdown into a categorisation based on their installation method. This is useful for discussion of many of the associated engineering problems of method and quality control of manufacture, vulnerability, access for installation and maintenance and ultimately system safety and reliability. The function and measured plasma parameter of specific diagnostics is covered in other papers and is not attempted here, neither is a full catalogue of Diagnostics on JET. (orig.)

  8. Comet Halley: nucleus and jets

    International Nuclear Information System (INIS)

    Sagdeev, R.Z.; Avanesov, G.A.; Barinov, I.V.

    1986-06-01

    The VEGA-1 and VEGA-2 spacecrafts made their closest approach to Comet Halley on 6 and 9 March, respectively. In this paper results of the onboard imaging experiment are discussed. The nucleus of the comet was clearly identifyable as an irregularly shaped object with overall dimensions of (16+-1)x(8+-1)x(8+-1) km. The nucleus rotates around its axis which is nearly perpendicular to the orbital plane, with a period of 53+-2 hours. Its albedo is only 0.04+-002. Most of the jet features observed during the second fly-by were spatially reconstructed. These sources form a quasi-linear structure on the surface. The dust above the surface is shown to be optically thin except certain specific dust jets. Brightness features on the surface are clearly seen. Correlating the data with other measurements it is concluded that the dirty snow-ball model probably has to be revised. (author)

  9. Detritiation studies for JET decommissioning

    Energy Technology Data Exchange (ETDEWEB)

    Perevezentsev, A.N.; Bell, A.C.; Williams, J.; Brennan, P.D. [EURATOM/UKAEA Fussion Association, Culham Science Centre, Abingdon (United Kingdom)

    2007-07-01

    JET is the world largest tokamak and has the capacity of operating with a tritium plasma. Three experimental campaigns, the Preliminary Tritium Experiment (0.1g T{sub 2}) in 1991, the Trace Tritium Experiment (5g T{sub 2}) in 2005, and the large experiment, the Deuterium-Tritium Experiment (DTE1) (100g T{sub 2}) in 1997, were carried out at JET with tritium plasmas. In DTE1 about 35 grams of tritium were fed directly into the vacuum vessel, with about 30% of this tritium being retained inside the vessel. In several years time JET will cease experimental operations and enter a decommissioning phase. In preparation for this the United Kingdom Atomic Energy Authority, the JET Operator, has been carrying out studies of various detritiation techniques. The materials which have been the subject of these studies include solid materials, such as various metals (Inconel 600 and 625, stainless steel 316L, beryllium, 'oxygen-free' copper, aluminium bronze), carbon fibre composite tiles, 'carbon' flakes and dust present in the vacuum vessel and also soft housekeeping materials. Liquid materials include organic liquids, such as vacuum oils and scintillation cocktails, and water. Detritiation of gas streams was also investigated. The purpose of the studies was to select and experimentally prove primary and auxiliary technologies for in-situ detritiation of in-vessel components and ex-situ detritiation of components removed from the vessel. The targets of ex-vessel detritiation were a reduction of the tritium inventory in and the rate of tritium out-gassing from the materials, and conversion, if possible, of intermediate level waste to low level waste and a reduction in volume of waste for disposal. The results of experimental trials and their potential application are presented. (orig.)

  10. Quantum chromodynamics and hadron jets

    International Nuclear Information System (INIS)

    Dokshitser, Y.L.; Dyakonov, D.I.

    1979-07-01

    These lectures are devoted to the description of the various properties of hard scattering processes with the participation of hadrons in the framework of Quantum Chromodynamics. We discuss in detail the validity and region of applicability of perturbation theory applied to hadron processes. Particular attention is paid to the question of the structure of quark and gluon jets produced in hard processes (as an example, e + e - annihilation into hadrons). In addition to giving a pedagogical review, we also present new results. (orig.)

  11. Ion temperature profiles in JET

    International Nuclear Information System (INIS)

    Hellermann, M. von; Mandl, W.; Summers, H.P.; Weisen, H.

    1989-01-01

    The results presented in this paper have shown some extreme cases of ion temperature profiles illustrating the different operation modes of the JET tokamak. In the three examples of low-density high temperature, high-density moderates and high-density high-confinement plasmas comparable values of a maximum fusion product n d T i τ E in the order of 10 20 keV m -3 sec are achieved. (author) 1 ref., 7 figs

  12. QGP and Modified Jet Fragmentation

    International Nuclear Information System (INIS)

    Wang, Xin-Nian

    2005-01-01

    Recent progresses in the study of jet modification in hotmedium and their consequences in high-energy heavy-ion collisions are reviewed. In particular, I will discuss energy loss for propagating heavy quarks and the resulting modified fragmentation function. Medium modification of the parton fragmentation function due to quark recombination are formulated within finite temperature field theory and their implication on the search for deconfined quark-gluon plasma is also discussed

  13. 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...

  14. Increased wind risk from sting-jet windstorms with climate change

    Science.gov (United States)

    Martínez-Alvarado, Oscar; Gray, Suzanne L.; Hart, Neil C. G.; Clark, Peter A.; Hodges, Kevin; Roberts, Malcolm J.

    2018-04-01

    Extra-tropical cyclones dominate autumn and winter weather over western Europe. The strongest cyclones, often termed windstorms, have a large socio-economic impact on landfall due to strong surface winds and coastal storm surges. Climate model integrations have predicted a future increase in the frequency of, and potential damage from, European windstorms and yet these integrations cannot properly represent localised jets, such as sting jets, that may significantly enhance damage. Here we present the first prediction of how the climatology of sting-jet-containing cyclones will change in a future warmer climate, considering the North Atlantic and Europe. A proven sting-jet precursor diagnostic is applied to 13 year present-day and future (~2100) climate integrations from the Met Office Unified Model in its Global Atmosphere 3.0 configuration. The present-day climate results are consistent with previously-published results from a reanalysis dataset (with around 32% of cyclones exhibiting the sing-jet precursor), lending credibility to the analysis of the future-climate integration. The proportion of cyclones exhibiting the sting-jet precursor in the future-climate integration increases to 45%. Furthermore, while the proportion of explosively-deepening storms increases only slightly in the future climate, the proportion of those storms with the sting-jet precursor increases by 60%. The European resolved-wind risk associated with explosively-deepening storms containing a sting-jet precursor increases substantially in the future climate; in reality this wind risk is likely to be further enhanced by the release of localised moist instability, unresolved by typical climate models.

  15. Jet Definitions in Effective Field Theory and Decaying Dark Matter

    Science.gov (United States)

    Cheung, William Man Yin

    2012-06-01

    In this thesis jet production and cosmological constraints on decaying dark matter are studied. The powerful framework of effective field theory is applied in both cases to further our knowledge of particle physics. We first discuss how to apply the Soft Collinear Effective Theory (SCET) for calculating hadronic jet production rate. By applying SCET power counting, we develop a consistent approach to perform phase space integrations. This approach is then successfully applied to one-loop calculations with regard to a variety of jet algorithms. This allows us to study if the soft contribution can be factorized from the collinear ones. In particular we point out the connection between such factorization and the choice of ultraviolet regulator. We then further our study of the (exclusive) kT and C/A jet algorithms in SCET with the introduction of an additional regulator. Regularizing the virtualities and rapidities of graphs in SCET, we are able to write the next-to-leading-order dijet cross section as the product of separate hard, jet, and soft contributions. We show how to reproduce the Sudakov form factor to next-to-leading logarithmic accuracy previously calculated by the coherent branching formalism. Our resummed expression only depends on the renormalization group evolution of the hard function, rather than on that of the hard and jet functions as is usual in SCET. Finally we present a complete analysis of the cosmological constraints on decaying dark matter. For this, we have updated and extended previous analyses to include Lyman-alpha forest, large scale structure, and weak lensing observations. Astrophysical constraints are not considered in this thesis. The bounds on the lifetime of decaying dark matter are dominated by either the late-time integrated Sachs-Wolfe effect for the scenario with weak reionization, or CMB polarisation observations when there is significant reionization. For the respective scenarios, the lifetimes for decaying dark matter are

  16. Fluid jet electric discharge source

    Science.gov (United States)

    Bender, Howard A [Ripon, CA

    2006-04-25

    A fluid jet or filament source and a pair of coaxial high voltage electrodes, in combination, comprise an electrical discharge system to produce radiation and, in particular, EUV radiation. The fluid jet source is composed of at least two serially connected reservoirs, a first reservoir into which a fluid, that can be either a liquid or a gas, can be fed at some pressure higher than atmospheric and a second reservoir maintained at a lower pressure than the first. The fluid is allowed to expand through an aperture into a high vacuum region between a pair of coaxial electrodes. This second expansion produces a narrow well-directed fluid jet whose size is dependent on the size and configuration of the apertures and the pressure used in the reservoir. At some time during the flow of the fluid filament, a high voltage pulse is applied to the electrodes to excite the fluid to form a plasma which provides the desired radiation; the wavelength of the radiation being determined by the composition of the fluid.

  17. Ancient Jets of Fiery Rain

    Science.gov (United States)

    Taylor, G. J.

    2015-04-01

    Chondrules are intriguing millimeter-sized crystallized droplets that are abundant in chondrites, so named because of the presence of numerous chondrules. They have puzzled cosmochemists since they were described by English scientist H. C. Sorby in 1877. Everyone agrees that they formed as molten droplets of silicates, but nobody agrees on how the little things formed. Ideas range from impacts onto asteroids, primary condensation in the solar nebula, shock waves and/or lightening in the solar nebula, or by processes operating as planets began to form. A new twist on this last idea was investigated in a new way by Brandon Johnson (Massachusetts Institute of Technology, MIT) and co-authors David Minton and Jay Melosh (Purdue University), and Maria Zuber at MIT. Johnson and coworkers modeled the effects of impacts between planetesimals 100-1000 kilometers in diameter. When such objects hit each other, the first thing that happens is jetting of molten rock. Johnson and colleagues propose that the jets will subdivide into droplets as the jetted material is shot into space. They estimate that the chondrules would have the correct cooling rates (as determined from previous studies of chondrules) and the collision frequency would be high enough to produce abundant chondrules. Johnson and coworkers suggest that chondrules are a "byproduct of [planetary] accretion."

  18. Vectoring of parallel synthetic jets

    Science.gov (United States)

    Berk, Tim; Ganapathisubramani, Bharathram; Gomit, Guillaume

    2015-11-01

    A pair of parallel synthetic jets can be vectored by applying a phase difference between the two driving signals. The resulting jet can be merged or bifurcated and either vectored towards the actuator leading in phase or the actuator lagging in phase. In the present study, the influence of phase difference and Strouhal number on the vectoring behaviour is examined experimentally. Phase-locked vorticity fields, measured using Particle Image Velocimetry (PIV), are used to track vortex pairs. The physical mechanisms that explain the diversity in vectoring behaviour are observed based on the vortex trajectories. For a fixed phase difference, the vectoring behaviour is shown to be primarily influenced by pinch-off time of vortex rings generated by the synthetic jets. Beyond a certain formation number, the pinch-off timescale becomes invariant. In this region, the vectoring behaviour is determined by the distance between subsequent vortex rings. We acknowledge the financial support from the European Research Council (ERC grant agreement no. 277472).

  19. Electric Currents along Astrophysical Jets

    Directory of Open Access Journals (Sweden)

    Ioannis Contopoulos

    2017-10-01

    Full Text Available Astrophysical black holes and their surrounding accretion disks are believed to be threaded by grand design helical magnetic fields. There is strong theoretical evidence that the main driver of their winds and jets is the Lorentz force generated by these fields and their associated electric currents. Several researchers have reported direct evidence for large scale electric currents along astrophysical jets. Quite unexpectedly, their directions are not random as would have been the case if the magnetic field were generated by a magnetohydrodynamic dynamo. Instead, in all kpc-scale detections, the inferred electric currents are found to flow away from the galactic nucleus. This unexpected break of symmetry suggests that a battery mechanism is operating around the central black hole. In the present article, we summarize observational evidence for the existence of large scale electric currents and their associated grand design helical magnetic fields in kpc-scale astrophysical jets. We also present recent results of general relativistic radiation magnetohydrodynamic simulations which show the action of the Cosmic Battery in the vicinity of astrophysical black holes.

  20. Distinguishing Isolated Photons from Jets

    CERN Document Server

    Pieri, Marco; Branson, James G

    2006-01-01

    We have developed isolation and shower-shape variables that are optimized for reducing the jet background for a high transverse-energy photon signal. To help understand the relative importance of each variable, we have computed the background rejection power as a function of signal efficiency for these variables as well as for some simple combinations of variables. We find that a combination of tracker plus ECAL information can give very significant background rejection power. By adding information from the HCAL, the rejection power can be improved. In addition we find that a very significant reduction in background can be achieved by adding photon shower shape information from the ECAL to the Neural Net inputs. About 1 in 200 jets contains a high E_T electromagnetic shower that is reconstructed by the CMS software and is therefore a potential background for photon detection. An additional jet rejection factor of 100 with 80% photon efficiency (or 400 with 50% efficiency) can be achieved by using the isolatio...

  1. The JET level-1 software

    International Nuclear Information System (INIS)

    McCullen, P.A.; Farthing, J.W.

    1998-01-01

    The complex nature of the JET machine requires a large amount of control parameter preparation, selection and validation before a pulse may be started. Level-1 is defined as the centralized, cross-subsystem control of JET. Before it was introduced over 10 years ago, the Session Leader (SL) who is responsible for specifying the parameter settings for a JET pulse, had virtually no software available to help him except for a simple editor used for the creation of control waveforms. Most of the required parameter settings were calculated by hand and then passed on either verbally or via hand-written forms. These parameters were then set by a large number of people - Local Unit Responsible Officers (LUROs) and CODAS Duty Officers (CDOs) using a wide selection of dedicated software. At this time the Engineer in Charge (EiC) would largely depend on the LUROs to inform him that conditions were ready. He never set control parameters personally and had little or no software available to him to see what many of the settings were. The first implementation of Level-1 software went some way towards improving the task of pulse schedule preparation in that the SL could specify his requirements via a computer interface and store them in a database for later use. At that time the maximum number of parameters that could be handled was 500. (author)

  2. Evaluation of dominant thyroid masses

    International Nuclear Information System (INIS)

    Thomas, C.G. Jr.; Buckwalter, J.A.; Staab, E.V.; Kerr, C.Y.

    1976-01-01

    Controversy exists concerning the management of solitary thyroid nodules because of conflicting information concerning the high clinical incidence of thyroid nodules, the varying incidence of cancer reported in those surgically excised and the infrequency of death from thyroid cancer. During the past several years, a plan for evaluating patients with dominant thyroid masses has evolved. The objective is to avoid unnecessary operations by identifying patients with a high risk of cancer. The criteria which are used are the age and sex of the patient, the duration of the mass, 125 I or /sup 99m/Tc scans, 75 Selenomethionine scans, B-mode ultrasonography and the response of the mass to suppressive therapy. This is a report of the findings in 222 patients who have been studied employing this approach. Thirty percent of the patients were operated upon. Forty percent had neoplasms (well differentiated cancer--28.8 percent, adenoma--12.1 percent), 47.0 percent--nodular goiter, 6.1 percent cysts, and 6.1 percent chronic thyroiditis. The incidence of cancer in the 222 patients was 8.6 percent and adenoma 3.6 percent. Patients at greatest risk of having cancer are those with solid nonfunctioning nodules which fail to regress with suppressive therapy. This study indicates that the approach described above is effective in selecting for surgical excision those individuals at greatest risk of having thyroid cancer

  3. The dominance behavioral system and manic temperament: Motivation for dominance, self-perceptions of power, and socially dominant behaviors

    OpenAIRE

    Johnson, Sheri L.; Carver, Charles S.

    2012-01-01

    The dominance behavioral system has been conceptualized as a biologically based system comprising motivation to achieve social power and self-perceptions of power. Biological, behavioral, and social correlates of dominance motivation and self-perceived power have been related to a range of psychopathological tendencies. Preliminary evidence suggests that mania and risk for mania (manic temperament) relate to the dominance system.

  4. A Three-decade X-band VLBI Study of 3CR Lobe-dominated Quasar Nuclei

    Directory of Open Access Journals (Sweden)

    Hough David H.

    2013-12-01

    Full Text Available We report X-band VLBI observations of several 3CR lobe-dominated quasar nuclei from 1981 to 2010, mostly obtained with the NRAO VLBA. The goal is to follow flux density outbursts and to fully determine the jet morphology and kinematics on 1-100 pc scales. In 3C207, the core region has flux outbursts at mean intervals of ~7 yr; one of these is actually a double outburst from a stationary true core and a swinging component ~0.5 mas apart. The position angle (PA of the swinging component varies by ~40°, while the PA values of the jet components span ~25°. The jet extends to ~25 mas. Average superluminal speeds are ~10c. One component shows apparent acceleration from 7c to 14c at 2-3 mas from the true core, in a jet recollimation zone that redirects the flow toward PA ~90°. Individual jet components expand until reaching the recollimation zone. In 3C263 and other objects, some of the same phenomena are seen, including ejection of jet components over a range in PA, superluminal motion, and apparent acceleration, but to a lesser degree. Possible physical interpretations involving beaming, orientation, projection, precession, and magnetic effects are discussed.

  5. On The Roman Domination Stable Graphs

    Directory of Open Access Journals (Sweden)

    Hajian Majid

    2017-11-01

    Full Text Available A Roman dominating function (or just RDF on a graph G = (V,E is a function f : V → {0, 1, 2} satisfying the condition that every vertex u for which f(u = 0 is adjacent to at least one vertex v for which f(v = 2. The weight of an RDF f is the value f(V (G = Pu2V (G f(u. The Roman domination number of a graph G, denoted by R(G, is the minimum weight of a Roman dominating function on G. A graph G is Roman domination stable if the Roman domination number of G remains unchanged under removal of any vertex. In this paper we present upper bounds for the Roman domination number in the class of Roman domination stable graphs, improving bounds posed in [V. Samodivkin, Roman domination in graphs: the class RUV R, Discrete Math. Algorithms Appl. 8 (2016 1650049].

  6. Dominant drivers of business students

    Directory of Open Access Journals (Sweden)

    Radu Cătălina

    2017-07-01

    Full Text Available Taibi Kahler wrote in 1974 a theory about five main drivers that could explain people’s motivation and a series of positive and negative behavior patterns: Be Strong, Be Perfect, Hurry Up, Try Hard and Please People. Of course, we consider there is no absolute positive or negative behavior, since (1 everything needs to be analyzed by taking into account the context and (2 any behavior pattern can mean a series of advantages as long as people understand their own values, beliefs, attitudes and behaviors. It would be interesting to link Kahler’s drivers to the educational process, in order to be able to adapt our courses and our teaching styles to students’ requirements and also to the requirements in the labor market. Our paper is built on literature review and a questionnaire applied to a sample of 607 students in Bucharest University of Economic Studies, Romania. Information was processed with Microsoft Excel 2013, in order to look at the main working styles our students have, at the main explanations for the differences between them and in order to test a series of hypotheses. We were interested to look at the main traits of the current generation of students in our university: dominant drivers, roles of managers and specialists, the attractiveness of the entrepreneurial career path, etc. and at a series of patterns (i.e. gender-related differences. We consider results of this study are useful both for teaching and research purposes. In terms of teaching, we plan to adapt our educational methods in order to improve the educational process.

  7. Heated water jet in coflowing turbulent stream

    International Nuclear Information System (INIS)

    Shirazi, M.A.; McQuivey, R.S.; Keefer, T.N.

    1974-01-01

    Effects of ambient turbulence on temperature and salinity distributions of heated water and neutrally buoyant saltwater jets were studied for a wide range of densimetric jet Froude numbers, jet discharge velocities, and ambient turbulence levels in a 4-ft-wide channel. Estimates of vertical and lateral diffusivity coefficients for heat and for salt were obtained from salinity and temperature distributions taken at several stations downstream of the injection point. Readily usable correlations are presented for plume center-line temperature, plume width, and trajectory. The ambient turbulence affects the gross behavior characteristics of the plume. The effects vary with the initial jet Froude number and the jet to ambient velocity ratio. Heat and salinity are transported similarly and the finite source dimensions and the initial jet characteristics alter the numerical value of the diffusivity

  8. Expanding plasma jet in a vacuum vessel

    International Nuclear Information System (INIS)

    Chutov, Yu.I.; Kravchenko, A.Yu.; Yakovetskij, V.S.

    1998-01-01

    The paper deals with numerical calculations of parameters of a supersonic quasi-neutral argon plasma jet expanding into a cylindrical vacuum vessel and interacting with its inner surface. A modified method of large particles was used, the complex set of hydrodynamic equations being broken into simpler components, each of which describes a separate physical process. Spatial distributions of the main parameters of the argon plasma jet were simulated at various times after the jet entering the vacuum vessel, the parameters being the jet velocity field, the full plasma pressure, the electron temperature, the temperature of heavy particles, and the degree of ionization. The results show a significant effect of plasma jet interaction on the plasma parameters. The jet interaction with the vessel walls may result e.g. in excitation of shock waves and rotational plasma motions. (J.U.)

  9. 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.

  10. Studies of heavy flavored jets with CMS

    CERN Document Server

    Jung, Kurt

    2017-01-01

    The energy loss of jets in heavy-ion collisions is expected to depend on the mass and flavor of the initiating parton. Thus, measurements of jet quenching with identified partons place powerful constraints on the thermodynamic and transport properties of the hot and dense medium. We present recent results of heavy flavor jet spectra and nuclear modification factors of jets associated to charm and bottom quarks in both pPb and PbPb collisions. New measurements to be presented include the dijet asymmetry of pairs of b-jets in PbPb collisions and a finalized c-jet measurement in pPb collisions based on new data collected during the 2015 heavy-ion run period at the LHC.

  11. Tagging partially reconstructed objects with jet substructure

    Energy Technology Data Exchange (ETDEWEB)

    Freytsis, Marat, E-mail: freytsis@uoregon.edu [Department of Physics, Harvard University, Cambridge, MA, 02138 (United States); Volansky, Tomer [Raymond and Beverly Sackler School of Physics and Astronomy, Tel-Aviv University, Tel-Aviv 69978 (Israel); Walsh, Jonathan R. [Ernest Orlando Lawrence Berkeley National Laboratory, University of California, Berkeley, CA 94720 (United States); Berkeley Center for Theoretical Physics, University of California, Berkeley, CA 94720 (United States)

    2017-06-10

    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.

  12. Solar Coronal Jets: Observations, Theory, and Modeling

    Science.gov (United States)

    Raouafi, N. E.; Patsourakos, S.; Pariat, E.; Young, P. R.; Sterling, A.; Savcheva, A.; Shimojo, M.; Moreno-Insertis, F.; Devore, C. R.; Archontis, V.; hide

    2016-01-01

    Chromospheric and coronal jets represent important manifestations of ubiquitous solar transients, which may be the source of signicant 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 ares and Coronal Mass Ejections (CMEs), jets share many common properties with these major 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 closeor 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 broadrange of solar-heliospheric problems.

  13. Tagging partially reconstructed objects with jet substructure

    International Nuclear Information System (INIS)

    Freytsis, Marat; Volansky, Tomer; Walsh, Jonathan R.

    2017-01-01

    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.

  14. Tagging partially reconstructed objects with jet substructure

    Science.gov (United States)

    Freytsis, Marat; Volansky, Tomer; Walsh, Jonathan R.

    2017-06-01

    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.

  15. Results on QCD jet production at ATLAS and CMS

    International Nuclear Information System (INIS)

    Meyer, C.J.

    2014-01-01

    The production of jets at the Large Hadron Collider (LHC) at √(s)=7 TeV is summarized, including results from both ATLAS and CMS detectors. Current jet performance is described, followed by inclusive jet and multi-jet measurements in various final state configurations. Finally some results on heavy flavour and jet substructure are presented. (author)

  16. Quark versus Gluon Jet Tagging Using Jet Images with the ATLAS Detector

    CERN Document Server

    The ATLAS collaboration

    2017-01-01

    Distinguishing quark-initiated from gluon-initiated jets is useful for many measurements and searches at the LHC. This note presents a jet tagger for distinguishing quark-initiated from gluon-initiated jets, which uses the full radiation pattern inside a jet processed as an image in a deep neural network classifier. The study is conducted using simulated dijet events in $\\sqrt{s}$=13 TeV pp collisions with the ATLAS detector. Across a wide range of quark jet identification efficiencies, the neural network tagger achieves a gluon jet rejection that is comparable to or better than the performance of the jet width and track multiplicity observables conventionally used for quark-versus-gluon jet tagging.

  17. Numerical analysis of jet impingement heat transfer at high jet Reynolds number and large temperature difference

    DEFF Research Database (Denmark)

    Jensen, Michael Vincent; Walther, Jens Honore

    2013-01-01

    was investigated at a jet Reynolds number of 1.66 × 105 and a temperature difference between jet inlet and wall of 1600 K. The focus was on the convective heat transfer contribution as thermal radiation was not included in the investigation. A considerable influence of the turbulence intensity at the jet inlet...... to about 100% were observed. Furthermore, the variation in stagnation point heat transfer was examined for jet Reynolds numbers in the range from 1.10 × 105 to 6.64 × 105. Based on the investigations, a correlation is suggested between the stagnation point Nusselt number, the jet Reynolds number......, and the turbulence intensity at the jet inlet for impinging jet flows at high jet Reynolds numbers. Copyright © 2013 Taylor and Francis Group, LLC....

  18. Boosted Jet Tagging with Jet-Images and Deep Neural Networks

    International Nuclear Information System (INIS)

    Kagan, Michael; Oliveira, Luke de; Mackey, Lester; Nachman, Benjamin; Schwartzman, Ariel

    2016-01-01

    Building on the jet-image based representation of high energy jets, we develop computer vision based techniques for jet tagging through the use of deep neural networks. Jet-images enabled the connection between jet substructure and tagging with the fields of computer vision and image processing. We show how applying such techniques using deep neural networks can improve the performance to identify highly boosted W bosons with respect to state-of-the-art substructure methods. In addition, we explore new ways to extract and visualize the discriminating features of different classes of jets, adding a new capability to understand the physics within jets and to design more powerful jet tagging methods

  19. Multiple zonal jets and convective heat transport barriers in a quasi-geostrophic model of planetary cores

    Science.gov (United States)

    Guervilly, C.; Cardin, P.

    2017-10-01

    We study rapidly rotating Boussinesq convection driven by internal heating in a full sphere. We use a numerical model based on the quasi-geostrophic approximation for the velocity field, whereas the temperature field is 3-D. This approximation allows us to perform simulations for Ekman numbers down to 10-8, Prandtl numbers relevant for liquid metals (˜10-1) and Reynolds numbers up to 3 × 104. Persistent zonal flows composed of multiple jets form as a result of the mixing of potential vorticity. For the largest Rayleigh numbers computed, the zonal velocity is larger than the convective velocity despite the presence of boundary friction. The convective structures and the zonal jets widen when the thermal forcing increases. Prograde and retrograde zonal jets are dynamically different: in the prograde jets (which correspond to weak potential vorticity gradients) the convection transports heat efficiently and the mean temperature tends to be homogenized; by contrast, in the cores of the retrograde jets (which correspond to steep gradients of potential vorticity) the dynamics is dominated by the propagation of Rossby waves, resulting in the formation of steep mean temperature gradients and the dominance of conduction in the heat transfer process. Consequently, in quasi-geostrophic systems, the width of the retrograde zonal jets controls the efficiency of the heat transfer.

  20. Jet energy scale corrections and their impact on measurements of the top-quark mass at CMS

    International Nuclear Information System (INIS)

    Kirschenmann, Henning

    2014-10-01

    The final state of many physics processes at the Large Hadron Collider (LHC) is dominated by jets, the experimental signature of quarks and gluons. The precise measurement of jets is a prerequisite to understand these processes. In this thesis, the determination of jet-energy corrections at CMS using dijet events is described, and the investigation of a correction specifically tailored to improve the reconstruction of b-jets in top-quark mass measurements is presented. Dijet events are used to determine the response relative to the central detector region in data and simulation as a function of the pseudorapidity η. Two complementary response estimators are introduced and detailed supplementary studies, e.g. of the time stability of the response, are performed. For the 2011 data-taking period, the MC/Data differences are found to be below 5% in the tracker-covered detector region with systematic uncertainties of less than 1%. Furthermore, a study of b-jet properties in 2012 data is presented. The correlation of various such observables with the response is exploited to improve the jet-energy measurement of b-jets. A resolution improvement of about 10% can be achieved, and the evaluation of b-jet specific jet-energy scale uncertainties (b-JES) indicates improvements of about 30%. This additional correction is applied to an existing measurement of the top-quark mass in the muon+jets channel. It leads to a statistical sensitivity improvement of about 10% and a reduction of systematic uncertainties related to the b-JES from 0.6 GeV to 0.3 GeV.

  1. The Q2 and Transverse Momentum Dependence of Jet Production in Photon-Photon Interactions

    International Nuclear Information System (INIS)

    Tylka, Allan Joseph

    1984-01-01

    An experimental study of jet production in photon-photon interactions is presented. The study is based on events collected with the PLUTO detector at the e + e - storage ring PETRA. The data sample, which corresponds to an integrated luminosity of ∼40 pb -1 taken at an e + e - center-of- mass energy of 34.6 GeV, consists of 1226 events in the so-called 'single-tagged' mode, in which only one of the scattered beam electrons is detected. The data sample extends over the kinematic ranges 0.1 < Q 2 < 18.0. GeV , where Q 2 is the squared invariant mass of the tagged virtual photon, and jet transverse momentum (p T ) up to ∼5 GeV/c, where p T is measured with respect to the photon-photon collision axis in the center-of-mass frame of the observed hadrons. At all Q 2 the data show a high p T tail characteristic of hard, point-like interactions, as exemplified by the fundamental reaction γγ → qq-bar. The jet production cross-section approaches the standard Quark Parton Model (QPM) expectation for fractionally-charged quarks of three colors from above as either Q 2 or jet p T increases. At Q 2 ≥ 10 GeV the observed cross-section is consistent with the standard QPM to within ∼20% statistical uncertainty at all values of p T . This result rules out the naive Han-Nambu integrally-charged quark model at a level of about five standard deviations. It is demonstrated that overall the data are consistent with the hypothesis of a two-jet final state. Moreover, the total jet production cross-section is shown to be well-described by an incoherent sum of the Generalized Vector Dominance Model (GVDM), for which the final state is hadronized as two oppositely-directed low p T jets, and the QPM, which accounts for final states consisting of two high p T jets. Some discrepancies between the data and the GVDM+QPM Ansatz are observed. At Q 2 ≤ 1 GeV 2 and 1.5 ≤ jet p T ≤ 4.0 GeV/c, the data lie systematically above the GVDM+QPM prediction. The thrust distribution

  2. Breakup Behavior of Molten Wood's Metal Jet in Subcooled Water

    Energy Technology Data Exchange (ETDEWEB)

    Heo, Hyo; Park, Seong Dae; Bang, In Cheol [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of); Jerng, Dong Wook [Chung-Ang Univ., Seoul (Korea, Republic of)

    2014-10-15

    There are safety characteristics of the metal fueled sodium fast-cooled reactor (SFR), by identifying the possibility of early termination of severe accidents. If the molten fuel is ejected from the cladding, the ejected molten fuel can interact with the coolant in the reactor vessel. This phenomenon is called as fuel-coolant interaction (FCI). The FCI occurs at the initial phase leading to severe accidents like core disruptive accident (CDA) in the SFR. A part of the corium energy is intensively transferred to the coolant in a very short time during the FCI. The coolant vaporizes at high pressure and expands so results in steam explosion that can threat to the integrity of nuclear reactor. The intensity of steam explosion is determined by jet breakup and the fragmentation behavior. Therefore, it is necessary to understand the jet breakup between the molten fuel jet and the coolant in order to evaluate whether the steam explosion occurs or not. The liquid jet breakup has been studied in various areas, such as aerosols, spray and combustion. In early studies, small diameter jets of low density liquids were studied. The jet breakup for large density liquids has been studied in nuclear reactor field with respect to safety. The existence of vapor film layer between the melt and liquid fluid is only in case of large density breakup. This paper deals with the jet breakup experiment in non-boiling conditions in order to analyze hydraulic effect on the jet behavior. In the present study, the wood's metal was used as the jet material. It has similar properties to the metal fuel. The physical properties of molten materials and coolants are listed in Table I, respectively. It is easy to conduct the experiment due to low melting point of the wood's metal. In order to clarify the dominant factors determining jet breakup and size distribution of the debris, the experiment that the molten wood's metal was injected into the subcooled condition was conducted. The

  3. The lund Monte Carlo for jet fragmentation

    International Nuclear Information System (INIS)

    Sjoestrand, T.

    1982-03-01

    We present a Monte Carlo program based on the Lund model for jet fragmentation. Quark, gluon, diquark and hadron jets are considered. Special emphasis is put on the fragmentation of colour singlet jet systems, for which energy, momentum and flavour are conserved explicitly. The model for decays of unstable particles, in particular the weak decay of heavy hadrons, is described. The central part of the paper is a detailed description on how to use the FORTRAN 77 program. (Author)

  4. Jet-calculus approach including coherence effects

    International Nuclear Information System (INIS)

    Jones, L.M.; Migneron, R.; Narayanan, K.S.S.

    1987-01-01

    We show how integrodifferential equations typical of jet calculus can be combined with an averaging procedure to obtain jet-calculus-based results including the Mueller interference graphs. Results in longitudinal-momentum fraction x for physical quantities are higher at intermediate x and lower at large x than with the conventional ''incoherent'' jet calculus. These results resemble those of Marchesini and Webber, who used a Monte Carlo approach based on the same dynamics

  5. Precision Jet production for the LHC

    CERN Multimedia

    CERN. Geneva

    2017-01-01

    Jet production is one of the basic processes at the LHC with numerous uses for standard model and BSM phenomenology. Understanding this process with suitable precision has been a long-standing goal for the particle physics community. I will report on our recent calculation of the NNLO contribution to jet production using antenna subtraction and discuss what these results might mean for jet phenomenology in the near future.

  6. Developments on jet reconstruction by DELPHI

    CERN Document Server

    Kiskinen, A

    2002-01-01

    The most relevant techniques used by DELPHI to identify jets in multihadronic final states are reviewed. The performance of jet reconstruction algorithms is analysed together with the additional use of energy and momentum conservation in order to allow for a precise reconstruction of the event kinematics. Also jet flavour tagging methods are summarised. Applications in some analyses like searches for new particles such as Higgs bosons, W mass physics and QCD studies are presented. (9 refs).

  7. Probing jet decoherence in heavy ion collisions

    Science.gov (United States)

    Casalderrey-Solana, Jorge; Mehtar-Tani, Yacine; Salgado, Carlos A.; Tywoniuk, Konrad

    2017-11-01

    We suggest to use the SofDrop jet grooming technique to investigate the sensitivity of jet substructure to color decoherence in heavy ion collisions. We propose in particular to analyze the two-prong probability angular distribution as a probe of the transition between the coherent and incoherent energy loss regimes. We predict an increasing suppression of two-prong substructures with angle as the medium resolves more jet substructure.

  8. Identified particles in quark and gluon jets

    CERN Document Server

    Abreu, P; Adye, T; Ajinenko, I; Alekseev, G D; Alemany, R; Allport, P P; Almehed, S; Amaldi, Ugo; Amato, S; Andreazza, A; Andrieux, M L; Antilogus, P; Apel, W D; Åsman, B; Augustin, J E; Augustinus, A; Baillon, Paul; Bambade, P; Barão, F; Barbi, M S; Barbiellini, Guido; Bardin, Dimitri Yuri; Barker, G; Baroncelli, A; Bärring, O; Barrio, J A; Bartl, Walter; Bates, M J; Battaglia, Marco; Baubillier, M; Baudot, J; Becks, K H; Begalli, M; Beillière, P; Belokopytov, Yu A; Benvenuti, Alberto C; Berggren, M; Bertini, D; Bertrand, D; Besançon, M; Bianchi, F; Bigi, M; Bilenky, S M; Billoir, P; Bizouard, M A; Bloch, D; Blume, M; Bolognese, T; Bonesini, M; Bonivento, W; Booth, P S L; Bosio, C; Botner, O; Boudinov, E; Bouquet, B; Bourdarios, C; Bowcock, T J V; Bozzo, M; Branchini, P; Brand, K D; Brenke, T; Brenner, R A; Bricman, C; Brown, R C A; Brückman, P; Brunet, J M; Bugge, L; Buran, T; Burgsmüller, T; Buschmann, P; Cabrera, S; Caccia, M; Calvi, M; Camacho-Rozas, A J; Camporesi, T; Canale, V; Canepa, M; Cankocak, K; Cao, F; Carena, F; Carroll, L; Caso, Carlo; Castillo-Gimenez, M V; Cattai, A; Cavallo, F R; Chabaud, V; Charpentier, P; Chaussard, L; Checchia, P; Chelkov, G A; Chen, M; Chierici, R; Chliapnikov, P V; Chochula, P; Chorowicz, V; Chudoba, J; Cindro, V; Collins, P; Contri, R; Cortina, E; Cosme, G; Cossutti, F; Cowell, J H; Crawley, H B; Crennell, D J; Crosetti, G; Cuevas-Maestro, J; Czellar, S; Dahl-Jensen, Erik; Dahm, J; D'Almagne, B; Dam, M; Damgaard, G; Dauncey, P D; Davenport, Martyn; Da Silva, W; Defoix, C; Deghorain, A; Della Ricca, G; Delpierre, P A; Demaria, N; De Angelis, A; de Boer, Wim; De Brabandere, S; De Clercq, C; La Vaissière, C de; De Lotto, B; De Min, A; De Paula, L S; De Saint-Jean, C; Dijkstra, H; Di Ciaccio, Lucia; Di Diodato, A; Djama, F; Djannati, A; Dolbeau, J; Doroba, K; Dracos, M; Drees, J; Drees, K A; Dris, M; Durand, J D; Edsall, D M; Ehret, R; Eigen, G; Ekelöf, T J C; Ekspong, Gösta; Elsing, M; Engel, J P; Erzen, B; Espirito-Santo, M C; Falk, E; Fassouliotis, D; Feindt, Michael; Ferrer, A; Fichet, S; Filippas-Tassos, A; Firestone, A; Fischer, P A; Föth, H; Fokitis, E; Fontanelli, F; Formenti, F; Franek, B J; Frenkiel, P; Fries, D E C; Frodesen, A G; Frühwirth, R; Fulda-Quenzer, F; Fuster, J A; Galloni, A; Gamba, D; Gandelman, M; García, C; García, J; Gaspar, C; Gasparini, U; Gavillet, P; Gazis, E N; Gelé, D; Gerber, J P; Gerdyukov, L N; Gokieli, R; Golob, B; Gopal, Gian P; Gorn, L; Górski, M; Guz, Yu; Gracco, Valerio; Graziani, E; Green, C; Grefrath, A; Gris, P; Grosdidier, G; Grzelak, K; Gumenyuk, S A; Gunnarsson, P; Günther, M; Guy, J; Hahn, F; Hahn, S; Hajduk, Z; Hallgren, A; Hamacher, K; Harris, F J; Hedberg, V; Henriques, R P; Hernández, J J; Herquet, P; Herr, H; Hessing, T L; Heuser, J M; Higón, E; Hilke, Hans Jürgen; Hill, T S; Holmgren, S O; Holt, P J; Holthuizen, D J; Hoorelbeke, S; Houlden, M A; Hrubec, Josef; Huet, K; Hultqvist, K; Jackson, J N; Jacobsson, R; Jalocha, P; Janik, R; Jarlskog, C; Jarlskog, G; Jarry, P; Jean-Marie, B; Johansson, E K; Jönsson, L B; Jönsson, P E; Joram, Christian; Juillot, P; Kaiser, M; Kapusta, F; Karafasoulis, K; Karlsson, M; Karvelas, E; Katargin, A; Katsanevas, S; Katsoufis, E C; Keränen, R; Khokhlov, Yu A; Khomenko, B A; Khovanskii, N N; King, B J; Kjaer, N J; Klapp, O; Klein, H; Klovning, A; Kluit, P M; Köne, B; Kokkinias, P; Koratzinos, M; Korcyl, K; Kostyukhin, V; Kourkoumelis, C; Kuznetsov, O; Krammer, Manfred; Kreuter, C; Kronkvist, I J; Krumshtein, Z; Krupinski, W; Kubinec, P; Kucewicz, W; Kurvinen, K L; Lacasta, C; Laktineh, I; Lamsa, J; Lanceri, L; Lane, D W; Langefeld, P; Lapin, V; Laugier, J P; Lauhakangas, R; Leder, Gerhard; Ledroit, F; Lefébure, V; Legan, C K; Leitner, R; Lemonne, J; Lenzen, Georg; Lepeltier, V; Lesiak, T; Libby, J; Liko, D; Lindner, R; Lipniacka, A; Lippi, I; Lörstad, B; Loken, J G; López, J M; Loukas, D; Lutz, P; Lyons, L; MacNaughton, J N; Maehlum, G; Mahon, J R; Malmgren, T G M; Malychev, V; Mandl, F; Marco, J; Marco, R P; Maréchal, B; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Martínez-Rivero, C; Martínez-Vidal, F; Martí i García, S; Masik, J; Matorras, F; Matteuzzi, C; Matthiae, Giorgio; Mazzucato, M; McCubbin, M L; McKay, R; McNulty, R; Medbo, J; Merk, M; Meroni, C; Meyer, S; Meyer, W T; Michelotto, M; Migliore, E; Mirabito, L; Mitaroff, Winfried A; Mjörnmark, U; Moa, T; Møller, R; Mönig, K; Monge, M R; Morettini, P; Müller, H; Münich, K; Mulders, M; Mundim, L M; Murray, W J; Muryn, B; Myatt, Gerald; Naraghi, F; Navarria, Francesco Luigi; Navas, S; Nawrocki, K; Negri, P; Neumann, W; Neumeister, N; Nicolaidou, R; Nielsen, B S; Nieuwenhuizen, M; Nikolaenko, V; Niss, P; Nomerotski, A; Normand, Ainsley; Novák, M; Oberschulte-Beckmann, W; Obraztsov, V F; Olshevskii, A G; Onofre, A; Orava, Risto; Österberg, K; Ouraou, A; Paganini, P; Paganoni, M; Pagès, P; Pain, R; Palka, H; Papadopoulou, T D; Papageorgiou, K; Pape, L; Parkes, C; Parodi, F; Passeri, A; Pegoraro, M; Peralta, L; Pernicka, Manfred; Perrotta, A; Petridou, C; Petrolini, A; Petrovykh, M; Phillips, H T; Piana, G; Pierre, F; Pimenta, M; Podobnik, T; Podobrin, O; Pol, M E; Polok, G; Poropat, P; Pozdnyakov, V; Privitera, P; Pukhaeva, N; Pullia, Antonio; Radojicic, D; Ragazzi, S; Rahmani, H; Rames, J; Ratoff, P N; Read, A L; Reale, M; Rebecchi, P; Redaelli, N G; Regler, Meinhard; Reid, D; Reinhardt, R; Renton, P B; Resvanis, L K; Richard, F; Richardson, J; Rídky, J; Rinaudo, G; Ripp, I; Romero, A; Roncagliolo, I; Ronchese, P; Roos, L; Rosenberg, E I; Roudeau, Patrick; Rovelli, T; Rückstuhl, W; Ruhlmann-Kleider, V; Ruiz, A; Rybicki, K; Rybin, A; Saarikko, H; Sacquin, Yu; Sadovskii, A; Sahr, O; Sajot, G; Salt, J; Sánchez, J; Sannino, M; Schimmelpfennig, M; Schneider, H; Schwickerath, U; Schyns, M A E; Sciolla, G; Scuri, F; Seager, P; Sedykh, Yu; Segar, A M; Seitz, A; Sekulin, R L; Serbelloni, L; Shellard, R C; Siegrist, P; Silvestre, R; Simonetti, S; Simonetto, F; Sissakian, A N; Sitár, B; Skaali, T B; Smadja, G; Smirnov, N; Smirnova, O G; Smith, G R; Sosnowski, R; Souza-Santos, D; Spassoff, Tz; Spiriti, E; Sponholz, P; Squarcia, S; Stampfer, D; Stanescu, C; Stanic, S; Stapnes, Steinar; Stavitski, I; Stevenson, K; Stocchi, A; Strauss, J; Strub, R; Stugu, B; Szczekowski, M; Szeptycka, M; Tabarelli de Fatis, T; Tavernet, J P; Chikilev, O G; Thomas, J; Tilquin, A; Timmermans, J; Tkatchev, L G; Todorov, T; Todorova, S; Toet, D Z; Tomaradze, A G; Tomé, B; Tonazzo, A; Tortora, L; Tranströmer, G; Treille, D; Tristram, G; Trombini, A; Troncon, C; Tsirou, A L; Turluer, M L; Tyapkin, I A; Tyndel, M; Tzamarias, S; Überschär, B; Ullaland, O; Uvarov, V; Valenti, G; Vallazza, E; Van der Velde, C; van Apeldoorn, G W; van Dam, P; Van Doninck, W K; Van Eldik, J; Van Lysebetten, A; Vassilopoulos, N; Vegni, G; Ventura, L; Venus, W A; Verbeure, F; Verlato, M; Vertogradov, L S; Vilanova, D; Vincent, P; Vitale, L; Vlasov, E; Vodopyanov, A S; Vrba, V; Wahlen, H; Walck, C; Weierstall, M; Weilhammer, Peter; Weiser, C; Wetherell, Alan M; Wicke, D; Wickens, J H; Wielers, M; Wilkinson, G R; Williams, W S C; Winter, M; Witek, M; Wlodek, T; Woschnagg, K; Yip, K; Yushchenko, O P; Zach, F; Zaitsev, A; Zalewska-Bak, A; Zalewski, Piotr; Zavrtanik, D; Zevgolatakos, E; Zimin, N I; Zito, M; Zontar, D; Zucchelli, G C; Zumerle, G

    1997-01-01

    A sample of about 1.4 million hadronic \\z decays, selected among the data recorded by the DELPHI detector at LEP during 1994, was used to measure for the first time the momentum spectra of \\kp, \\ko, \\p, \\l and their antiparticles in gluon and quark jets. As observed for inclusive charged particles, the production spectra of identified particles were found to be softer in gluon jets than in quark jets, with a higher total multiplicity.

  9. A Boundary Property for Upper Domination

    KAUST Repository

    AbouEisha, Hassan M.; Hussain, Shahid; Lozin, Vadim; Monnot, Jé rô me; Ries, Bernard; Zamaraev, Viktor

    2016-01-01

    An upper dominating set in a graph is a minimal (with respect to set inclusion) dominating set of maximum cardinality.The problem of finding an upper dominating set is generally NP-hard, but can be solved in polynomial time in some restricted graph

  10. Jet shapes at D0 and CDF

    International Nuclear Information System (INIS)

    Streets, K.T.

    1995-05-01

    The distribution of the transverse energy in jets has been measured in p bar p collisions at √s = 1.8 TeV at the Fermilab Tevatron collider using the CDF and DO detectors. This measurement of the jet shape is made as a function of jet transverse energy in both experiments and as a function of the jet pseudorapidity in the D0 experiment. Comparisons to Monte Carlo simulations and next-to-leading order partonic QCD calculations, Ο(α s 3 ), are presented

  11. Jets and large Psub(T) phenomena

    Energy Technology Data Exchange (ETDEWEB)

    Narayan, D. S.

    1980-07-01

    Jets have been observed in hadron-hadron collisions and e/sup +/e/sup -/ annihilation at high energies. An attempt is made to explain the mechanism for the production of jets. The mechanism of quark-fragmentation is described with illustrations. Basic concepts and assumptions are used to study the distribution of quarks and gluons in a hadron. Quark and gluon decay distributions, and the transverse momentum distributions of quarks and gluons, Monte-Carlo methods in the study of jets, large Psub(T) phenomena in hadrons, QCD effects in hadronization of quark jets are discussed.

  12. b-Jet Identification in CMS

    CERN Document Server

    AUTHOR|(CDS)2081921

    2016-01-01

    A large fraction of the CMS physics program relies on the identification of jets containing the decay of a B hadron (b jets). The b jets can be discriminated from jets produced by the hadronization of light quarks based on characteristic properties of B hadrons, such as the long lifetime or the presence of soft leptons produced during their decay.An overview of the large variety of b-tagging algorithms and the measurement of their performance with data collected in 2011 and 2012 are presented in this talk. A special focus lies on new methods of b-tagging in jet substructure.As the excluded mass regions for new physics beyond the Standard Model continue to increase, searches often focus on boosted final states characterized by particles with large transverse momenta. In the boosted regime the resulting decay products for hadronic decays of heavy particles tend to be collimated and can fall within a single jet, known as fat-jet. In this case, selections based on multiple jets cannot be applied and jet substruct...

  13. Laser cutting technology using water jet waveguide

    International Nuclear Information System (INIS)

    Akiba, Miyuki; Shiihara, Katsunori; Chida, Itaru

    2013-01-01

    Laser with water jet is examined to cut in-vessel structure. However, it is necessary to increase the break-up length of water jet to cut a thick plate. Therefore, the effects of the water jet parameter (water pressure, assist gas, laser power) on break-up length were investigated. It was found from observation results of water jet that the longest break-up length is about 135mm under condition of water pressure 40 MPa, laser power 30W and helium assist gas 1L/min. (author)

  14. On the structure of pulsed plasma jets

    Science.gov (United States)

    Cavolowsky, John Arthur

    A pulsed plasma jet is a turbulent, inhomogeneous fluid mechanical discharge capable of initiating and inhancing combustion. Having shown the ability to ignite lean fuel mixtures, is now offers the potential for real-time control of combustion processes. The fluid mechanical and chemical properties of such jets are explored. The fluid mechanical structure of the jet was examined using two optical diagnostic techniques. Self-light streak photography provided information on the motion of luminous gas particles in its core. The turbulent, thermal evolution of the jet was explored using high speed laser schlieren cinematography. By examine plasma jet generators with both opaque and transparent plasma cavities, detailed information on plasma formation and jet structure, beginning with the electric arc discharge in the cavity, was obtained. Molecular beam mass spectroscopy was used to determine temperature and species concentration in the jet. Both noncombustible and combustible jets were studied. Species measurements in combustible jets revealed significant concentrations of radicals and products of complete as well as incomplete combustion.

  15. Cold plasma decontamination using flexible jet arrays

    Science.gov (United States)

    Konesky, Gregory

    2010-04-01

    Arrays of atmospheric discharge cold plasma jets have been used to decontaminate surfaces of a wide range of microorganisms quickly, yet not damage that surface. Its effectiveness in decomposing simulated chemical warfare agents has also been demonstrated, and may also find use in assisting in the cleanup of radiological weapons. Large area jet arrays, with short dwell times, are necessary for practical applications. Realistic situations will also require jet arrays that are flexible to adapt to contoured or irregular surfaces. Various large area jet array prototypes, both planar and flexible, are described, as is the application to atmospheric decontamination.

  16. Jet suppression measurement with the ATLAS detector

    CERN Document Server

    AUTHOR|(INSPIRE)INSPIRE-00443411; The ATLAS collaboration

    2016-01-01

    A hot medium with a high density of unscreened color charges is produced in relativistic heavy ion collisions. Jets are produced at the early stages of this collision and are known to become attenuated as they propagate through the hot matter. One manifestation of this energy loss is a lower yield of jets emerging from the medium than expected in the absence of medium effects. Another manifestation of the energy loss is the modification of the dijet balance and the modification of fragmentation functions. In these proceedings, the latest ATLAS results on single jet suppression, dijet suppression, and modification of the jet internal structure in \\PbPb~collisions are presented.

  17. Epigenetic dominance of prion conformers.

    Directory of Open Access Journals (Sweden)

    Eri Saijo

    2013-10-01

    Full Text Available Although they share certain biological properties with nucleic acid based infectious agents, prions, the causative agents of invariably fatal, transmissible neurodegenerative disorders such as bovine spongiform encephalopathy, sheep scrapie, and human Creutzfeldt Jakob disease, propagate by conformational templating of host encoded proteins. Once thought to be unique to these diseases, this mechanism is now recognized as a ubiquitous means of information transfer in biological systems, including other protein misfolding disorders such as those causing Alzheimer's and Parkinson's diseases. To address the poorly understood mechanism by which host prion protein (PrP primary structures interact with distinct prion conformations to influence pathogenesis, we produced transgenic (Tg mice expressing different sheep scrapie susceptibility alleles, varying only at a single amino acid at PrP residue 136. Tg mice expressing ovine PrP with alanine (A at (OvPrP-A136 infected with SSBP/1 scrapie prions propagated a relatively stable (S prion conformation, which accumulated as punctate aggregates in the brain, and produced prolonged incubation times. In contrast, Tg mice expressing OvPrP with valine (V at 136 (OvPrP-V136 infected with the same prions developed disease rapidly, and the converted prion was comprised of an unstable (U, diffusely distributed conformer. Infected Tg mice co-expressing both alleles manifested properties consistent with the U conformer, suggesting a dominant effect resulting from exclusive conversion of OvPrP-V136 but not OvPrP-A136. Surprisingly, however, studies with monoclonal antibody (mAb PRC5, which discriminates OvPrP-A136 from OvPrP-V136, revealed substantial conversion of OvPrP-A136. Moreover, the resulting OvPrP-A136 prion acquired the characteristics of the U conformer. These results, substantiated by in vitro analyses, indicated that co-expression of OvPrP-V136 altered the conversion potential of OvPrP-A136 from the S to

  18. Input-output analysis of high-speed turbulent jet noise

    Science.gov (United States)

    Jeun, Jinah; Nichols, Joseph W.

    2015-11-01

    We apply input-output analysis to predict and understand the aeroacoustics of high-speed isothermal turbulent jets. We consider axisymmetric linear perturbations about Reynolds-averaged Navier-Stokes solutions of ideally expanded turbulent jets with Mach numbers 0 . 6 parabolized stability equations (PSE), and this mode dominates the response. For subsonic jets, however, the singular values indicate that the contributions of suboptimal modes to noise generation are nearly equal to that of the optimal mode, explaining why PSE misses some of the farfield sound in this case. Finally, high-fidelity large eddy simulation (LES) is used to assess the prevalence of suboptimal modes in the unsteady data. By projecting LES data onto the corresponding input modes, the weighted gain of each mode is examined.

  19. Long range correlation in Higgs boson plus two jets production at the LHC

    Energy Technology Data Exchange (ETDEWEB)

    Sun, Peng [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Nuclear Science Division; Yuan, C. -P. [Michigan State Univ., East Lansing, MI (United States). Dept. of Physics and Astronomy; Yuan, Feng [Lawrence Berkeley National Lab. (LBNL), Berkeley, CA (United States). Nuclear Science Division

    2016-09-09

    Here, we study Higgs boson plus two high energy jets production at the LHC in the kinematics where the two jets are well separated in rapidity. The partonic processes are dominated by the t-channel weak boson fusion (WBF) and gluon fusion (GF) contributions. We derive the associated QCD resummation formalism for the correlation analysis where the total transverse momentum q⊥ of the Higgs boson and two jets is small. Because of different color structures, the resummation results lead to distinguished behaviors: the WBF contribution peaks at relative low q⊥ while all GF channel contributions are strongly de-correlated and spread to a much wider q⊥ range. Furthermore, by applying a kinematic cut on q⊥, one can effectively increase the WBF signal to the GF background by a significant factor. This, then strengthens the ability to investigate the WBF channel in Higgs boson production and study the couplings of Higgs to electroweak bosons.

  20. Thrust distribution of two-jet like events at a photon-photon collider

    International Nuclear Information System (INIS)

    Kanakubo, Fumiko

    1995-01-01

    One of the advantages of using a photon-photon collision with the same helicity is that the continuum qq-bar production is suppressed at the lowest order (α s 0 ). However, the helicity suppression does not take place for the gluon radiation process, and qq-barg can be two-jet like. We evaluate the cross sections of the two-jet like events in a photon-photon collision, and present the thrust distributions. We take into account the QCD effect to all orders in α s in the leading-double-log approximation, and show the suppression due to this effect. The evaluation with the energy and the polarization distributions of the photon suggests that the contaminating photons with the opposite helicity contribute dominantly to the two-jet like process. (author)

  1. Numerical and experimental study on a pulsed-dc plasma jet

    Science.gov (United States)

    Liu, X. Y.; Pei, X. K.; Lu, X. P.; Liu, D. W.

    2014-06-01

    A numerical and experimental study of plasma jet propagation in a low-temperature, atmospheric-pressure, helium jet in ambient air is presented. A self-consistent, multi-species, two-dimensional axially symmetric plasma model with detailed finite-rate chemistry of helium-air mixture composition is used to provide insights into the propagation of the plasma jet. The obtained simulation results suggest that the sheath forms near the dielectric tube inner surface and shields the plasma channel from the tube surface. The strong electric field at the edge of the dielectric field enhances the ionization in the air mixing layer; therefore, the streamer head becomes ring-shaped when the streamer runs out of the tube. The avalanche-to-streamer transition is the main mechanism of streamer advancement. Penning ionization dominates the ionization reactions and increases the electrical conductivity of the plasma channel. The simulation results are supported by experimental observations under similar discharge conditions.

  2. QCD predictions for four-jet final states in e/sup +/e/sup -/ annihilation

    Energy Technology Data Exchange (ETDEWEB)

    Ali, A; Koerner, J G; Kunszt, Z; Pietarinen, E [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany, F.R.); Kramer, G; Schierholz, G; Willrodt, J [Hamburg Univ. (Germany, F.R.). 2. Inst. fuer Theoretische Physik

    1980-05-01

    We have calculated the four-jet production processes e/sup +/e/sup -/ ..-->.. q anti q gg and e/sup -/e/sup -/ ..-->.. q anti q q anti q to lowest order QCD perturbation theory. We find that (q anti q q anti q) production is small compared to the dominant process e/sup +/e/sup -/ ..-->.. q anti q gg which can in part be traced to the fact that the latter process is more singular as the 2- and 3-jet phase-space limits are approached. We present differential 4-jet acoplanarity distributions and compare them with non-perturbative acoplanarity distributions at maximum PETRA and PEP energies. Leading log cross-section formulae are derived for various cut-off procedures and are compared to the results of our numerical integrations. We also present results on associated heavy quark production in e/sup +/e/sup -/ annihilation.

  3. Impingement heat/mass transfer to hybrid synthetic jets and other reversible pulsating jets

    Czech Academy of Sciences Publication Activity Database

    Trávníček, Zdeněk; Vít, T.

    2015-01-01

    Roč. 85, June (2015), s. 473-487 ISSN 0017-9310 R&D Projects: GA ČR GA14-08888S Institutional support: RVO:61388998 Keywords : impinging jet * reversible pulsating jet * synthetic jet Subject RIV: JU - Aeronautics, Aerodynamics, Aircrafts Impact factor: 2.857, year: 2015 http://www.sciencedirect.com/science/article/pii/S001793101500143X

  4. Editorial on Future Jet Technologies

    Science.gov (United States)

    Gal-Or, Benjamin

    2014-12-01

    The jet engine is the prime flight controller in post-stall flight domains where conventional flight control fails, or when the engine prevents catastrophes in training, combat, loss of all airframe hydraulics (the engine retains its own hydraulics), loss of one engine, pilot errors, icing on the wings, landing gear and runway issues in takeoff and landing and in bad-whether recoveries. The scientific term for this revolutionary technology is "jet-steering", and in engineering practice - "thrust vectoring", or "TV". Jet-Steering in advanced fighter aircraft designs is integrated with stealth technology. The resulting classified Thrust-Vectoring-Stealth ("TVS") technology has generated a second jet-revolution by which all Air-&-Sea-Propulsion Science and R&D are now being reassessed. Classified F-22, X-47B/C and RQ-180 TVS-vehicles stand at the front of this revolution. But recent transfers of such sensitive technologies to South Korea and Japan [1-5], have raised various fundamental issues that are evaluated by this editorial-review. One, and perhaps a key conclusion presented here, means that both South Korea and Japan may have missed one of their air-&-sea defenses: To develop and field low-cost unmanned fleets of jet-drones, some for use with expensive, TVS-fighter aircraft in highly congested areas. In turn, the U.S., EU, Russia and China, are currently developing such fleets at various TVS levels and sizes. China, for instance, operates at least 15,000 drones ("UAVs") by 2014 in the civilian sector alone. All Chinese drones have been developed by at least 230 developers/manufacturers [1-16]. Mobile telecommunication of safe links between flyers and combat drones ("UCAVs") at increasingly deep penetrations into remote, congested areas, can gradually be purchased-developed-deployed and then operated by extant cader of tens of thousands "National Champion Flyers" who have already mastered the operation of mini-drones in free-to-all sport clubs under national

  5. Jet Noise Modeling for Supersonic Business Jet Application

    Science.gov (United States)

    Stone, James R.; Krejsa, Eugene A.; Clark, Bruce J.

    2004-01-01

    This document describes the development of an improved predictive model for coannular jet noise, including noise suppression modifications applicable to small supersonic-cruise aircraft such as the Supersonic Business Jet (SBJ), for NASA Langley Research Center (LaRC). For such aircraft a wide range of propulsion and integration options are under consideration. Thus there is a need for very versatile design tools, including a noise prediction model. The approach used is similar to that used with great success by the Modern Technologies Corporation (MTC) in developing a noise prediction model for two-dimensional mixer ejector (2DME) nozzles under the High Speed Research Program and in developing a more recent model for coannular nozzles over a wide range of conditions. If highly suppressed configurations are ultimately required, the 2DME model is expected to provide reasonable prediction for these smaller scales, although this has not been demonstrated. It is considered likely that more modest suppression approaches, such as dual stream nozzles featuring chevron or chute suppressors, perhaps in conjunction with inverted velocity profiles (IVP), will be sufficient for the SBJ.

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

    Energy Technology Data Exchange (ETDEWEB)

    Li, Gang, E-mail: ligang@iet.cn [Key laboratory of light duty gas turbine, Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190 (China); Jiang, Xi [School of Engineering and Materials Science, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Zhao, Yujun [School of Mechanism, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044 (China); Liu, Cunxi [Key laboratory of light duty gas turbine, Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190 (China); Chen, Qi [School of Mechanism, Electronic and Control Engineering, Beijing Jiaotong University, Beijing 100044 (China); Xu, Gang; Liu, Fuqiang [Key laboratory of light duty gas turbine, Institute of Engineering Thermophysics, Chinese Academy of Sciences, Beijing 100190 (China)

    2017-04-04

    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. - Highlights: • The discharge does not ignite the mixture nor does it induce flashback. • The prominent advantage of this novel plasma swirler is its swirl number adjustable without any mechanical movement. • The frequency of the plasma swirler is adjustable. • The plasma swirler can be used as an oscillator to the reactants. • The plasma swirler can be used alone or combine with other traditional swirlers.

  7. KILOPARSEC-SCALE JETS IN THREE RADIO-LOUD NARROW-LINE SEYFERT 1 GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Richards, Joseph L.; Lister, Matthew L., E-mail: jlr@purdue.edu [Department of Physics and Astronomy, Purdue University, 525 Northwestern Avenue, West Lafayette, IN 47907 (United States)

    2015-02-10

    We have discovered kiloparsec-scale extended radio emission in three narrow-line Seyfert 1 galaxies (NLS1s) in sub-arcsecond resolution 9 GHz images from the Karl G. Jansky Very Large Array. We find all sources show two-sided, mildly core-dominated jet structures with diffuse lobes dominated by termination hotspots. These span 20–70 kpc with morphologies reminiscent of FR II radio galaxies, while the extended radio luminosities are intermediate between FR I and FR II sources. In two cases the structure is linear, while a 45° bend is apparent in the third. Very Long Baseline Array images at 7.6 GHz reveal parsec-scale jet structures, in two cases with extended structure aligned with the inner regions of the kiloparsec-scale jets. Based on this alignment, the ratio of the radio core–luminosity to the optical luminosity, the jet/counter-jet intensity and extension length ratios, and moderate core brightness temperatures (≲10{sup 10} K), we conclude these jets are mildly relativistic (β≲0.3, δ∼1−1.5) and aligned at moderately small angles to the line of sight (10–15°). The derived kinematic ages of ∼10{sup 6}–10{sup 7} yr are much younger than radio galaxies but comparable to other NLS1s. Our results increase the number of radio-loud NLS1s with known kiloparsec-scale extensions from 7 to 10 and suggest that such extended emission may be common, at least among the brightest of these sources.

  8. Transition to turbulence and noise radiation in heated coaxial jet flows

    Energy Technology Data Exchange (ETDEWEB)

    Gloor, Michael, E-mail: gloor@ifd.mavt.ethz.ch; Bühler, Stefan; Kleiser, Leonhard [Institute of Fluid Dynamics, ETH Zurich, 8092 Zurich (Switzerland)

    2016-04-15

    Laminar-turbulent transition and noise radiation of a parametrized set of subsonic coaxial jet flows with a hot primary (core) stream are investigated numerically by Large-Eddy Simulation (LES) and direct noise computation. This study extends our previous research on local linear stability of heated coaxial jet flows by analyzing the nonlinear evolution of initially laminar flows disturbed by a superposition of small-amplitude unstable eigenmodes. First, a baseline configuration is studied to shed light on the flow dynamics of coaxial jet flows. Subsequently, LESs are performed for a range of Mach and Reynolds numbers to systematically analyze the influences of the temperature and the velocity ratios between the primary and the secondary (bypass) stream. The results provide a basis for a detailed analysis of fundamental flow-acoustic phenomena in the considered heated coaxial jet flows. Increasing the primary-jet temperature leads to an increase of fluctuation levels and to an amplification of far-field noise, especially at low frequencies. Strong mixing between the cold bypass stream and the hot primary stream as well as the intermittent character of the flow field at the end of the potential core lead to a pronounced noise radiation at an aft angle of approximately 35{sup ∘}. The velocity ratio strongly affects the shear-layer development and therefore also the noise generation mechanisms. Increasing the secondary-stream velocity amplifies the dominance of outer shear-layer perturbations while the disturbance growth rates in the inner shear layer decrease. Already for r{sub mic} > 40R{sub 1}, where r{sub mic} is the distance from the end of the potential core and R{sub 1} is the core-jet radius, a perfect 1/r{sub mic} decay of the sound pressure amplitudes is observed. The potential-core length increases for higher secondary-stream velocities which leads to a shift of the center of the dominant acoustic radiation in the downstream direction.

  9. An Operational Model for the Prediction of Jet Blast

    Science.gov (United States)

    2012-01-09

    This paper presents an operational model for the prediction of jet blast. The model was : developed based upon three modules including a jet exhaust model, jet centerline decay : model and aircraft motion model. The final analysis was compared with d...

  10. Commercial jet fuel quality control

    Energy Technology Data Exchange (ETDEWEB)

    Strauss, K.H.

    1995-05-01

    The paper discusses the purpose of jet fuel quality control between the refinery and the aircraft. It describes fixed equipment, including various types of filters, and the usefulness and limitations of this equipment. Test equipment is reviewed as are various surveillance procedures. These include the Air Transport Association specification ATA 103, the FAA Advisory Circular 150/5230-4, the International Air Transport Association Guidance Material for Fuel Quality Control and Fuelling Service and the Guidelines for Quality Control at Jointly Operated Fuel Systems. Some past and current quality control problems are briefly mentioned.

  11. Neutron activation studies on JET

    International Nuclear Information System (INIS)

    Loughlin, M.J.; Forrest, R.A.; Edwards, J.E.G.

    2001-01-01

    Extensive neutron transport calculations have been performed to determine the neutron spectrum at a number of points throughout the JET torus hall. The model has been bench-marked against a set of foil activation measurements which were activated during an experimental campaign with deuterium/tritium plasmas. The model can predict the neutron activation of the foils on the torus hall walls to within a factor of three for reactions with little sensitivity to thermal neutrons. The use of scandium foils with and without a cadmium thermal neutron absorber was a useful monitor of the thermal neutron flux. Conclusions regarding the usefulness of other foils for benchmarking the calculations are also given

  12. Overview of the JET results

    Czech Academy of Sciences Publication Activity Database

    Romanelli, F.; Abhangi, M.; Abreu, P.; Aftanas, Milan; Afzal, M.; Aggarwal, K.M.; Aho-Mantila, L.; Ahonen, E.; Aints, M.; Airila, M.; Albanese, R.; Bílková, Petra; Cahyna, Pavel; Dejarnac, Renaud; Ďuran, Ivan; Fuchs, Vladimír; Horáček, Jan; Imríšek, M.; Janky, Filip; Ješko, Karol; Markovič, Tomáš; Mlynář, Jan; Peterka, Matěj; Petržílka, Václav; Tomeš, Matěj; Vondráček, Petr

    2015-01-01

    Roč. 55, č. 10 (2015), s. 104001 ISSN 0029-5515. [Fusion Energy Conference (FEC)/25./. St Petersburg, 13.10.2014-18.10.2014] Institutional support: RVO:61389021 Keywords : ITER-like wall * JET * tokamaks * magnetic confinement Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 4.040, year: 2015 http://iopscience.iop.org/article/10.1088/0029-5515/55/10/104001/meta;jsessionid=3FA2A9AC9BDFE6B4A43C77C9CF6C0DF0.c2.iopscience.cld.iop.org

  13. The semi-inclusive jet function in SCET and small radius resummation for inclusive jet production

    International Nuclear Information System (INIS)

    Kang, Zhong-Bo; Ringer, Felix; Vitev, Ivan

    2016-01-01

    We introduce a new kind of jet function: the semi-inclusive jet function J_i(z,ω_J,μ), which describes how a parton i is transformed into a jet with a jet radius R and energy fraction z=ω_J/ω, with ω_J and ω being the large light-cone momentum component of the jet and the corresponding parton i that initiates the jet, respectively. Within the framework of Soft Collinear Effective Theory (SCET) we calculate both J_q(z,ω_J,μ) and J_g(z,ω_J,μ) to the next-to-leading order (NLO) for cone and anti-k_T algorithms. We demonstrate that the renormalization group (RG) equations for J_i(z,ω_J,μ) follow exactly the usual DGLAP evolution, which can be used to perform the ln R resummation for inclusive jet cross sections with a small jet radius R. We clarify the difference between our RG equations for J_i(z,ω_J,μ) and those for the so-called unmeasured jet functions J_i(ω_J,μ), widely used in SCET for exclusive jet production. Finally, we present applications of the new semi-inclusive jet functions to inclusive jet production in e"+e"− and pp collisions. We demonstrate that single inclusive jet production in these collisions shares the same short-distance hard functions as single inclusive hadron production, with only the fragmentation functions D_i"h(z,μ) replaced by J_i(z,ω_J,μ). This can facilitate more efficient higher-order analytical computations of jet cross sections. We further match our ln R resummation at both LL_R and NLL_R to fixed NLO results and present the phenomenological implications for single inclusive jet production at the LHC.

  14. Jet Mass Reconstruction with the ATLAS Detector in Run 2

    CERN Document Server

    Jansky, Roland; The ATLAS collaboration

    2016-01-01

    The details of the ATLAS jet mass reconstruction and calibration are presented. In particular, the jet mass scale is calibrated using Monte Carlo simulation for large-radius groomed jets. Corresponding uncertainties are presented. An alternative jet mass definition that incorporates tracking information called the track-assisted jet mass is introduced and its performance is compared to the traditional calorimeter-only jet mass definition. An outlook on future improvments is also given.

  15. Study Of Boosted W-Jets And Higgs-Jets With the SiFCC Detector

    Energy Technology Data Exchange (ETDEWEB)

    Yu, Shin-Shan [Taiwan, Natl. Central U.; Chekanov, Sergei [Argonne; Gray, Lindsey [Fermilab; Kotwal, Ashutosh [Duke U.; Sen, Sourav [Duke U.; Tran, Nhan Viet [Fermilab

    2016-11-04

    We study the detector performance in the reconstruction of hadronically-decaying W bosons and Higgs bosons at very high energy proton colliders using a full GEANT4 simulation of the SiFCC detector. The W and Higgs bosons carry transverse momentum in the multi-TeV range, which results in collimated decay products that are reconstructed as a single jet. We present a measurement of the energy response and resolution of boosted W-jets and Higgs-jets and show the separation of two sub-jets within the boosted boson jet.

  16. Development of an empirical correlation for flow characteristics of turbulent jet by steam jet condensation

    International Nuclear Information System (INIS)

    Kang, H. S.; Kim, Y. S.; Youn, Y. J.; Song, C. H.

    2008-01-01

    An experimental research was performed to develop an empirical correlation of the turbulent water jet induced by the steam jet through a single hole in a subcooled water pool. A moveable pitot tube including a thermal couple was used to measure a local velocity and temperature of the turbulent water jet. The experimental results show that the velocity and the temperature distributions agree well with the theory of axially symmetric turbulent jet. The correlation predicting the maximum velocity of the turbulent jet was modified from the previous correlation and a new correlation to predict the characteristic length was developed based on the test results

  17. The dominance behavioral system and manic temperament: motivation for dominance, self-perceptions of power, and socially dominant behaviors.

    Science.gov (United States)

    Johnson, Sheri L; Carver, Charles S

    2012-12-15

    The dominance behavioral system has been conceptualized as a biologically based system comprising motivation to achieve social power and self-perceptions of power. Biological, behavioral, and social correlates of dominance motivation and self-perceived power have been related to a range of psychopathological tendencies. Preliminary evidence suggests that mania and risk for mania (manic temperament) relate to the dominance system. Four studies examine whether manic temperament, measured with the Hypomanic Personality Scale (HPS), is related to elevations in dominance motivation, self-perceptions of power, and engagement in socially dominant behavior across multiple measures. In Study 1, the HPS correlated with measures of dominance motivation and the pursuit of extrinsically-oriented ambitions for fame and wealth among 454 undergraduates. In Study 2, the HPS correlated with perceptions of power and extrinsically-oriented lifetime ambitions among 780 undergraduates. In Study 3, the HPS was related to trait-like tendencies to experience hubristic (dominance-related) pride, as well as dominance motivation and pursuit of extrinsically-oriented ambitions. In Study 4, we developed the Socially Dominant Behavior Scale to capture behaviors reflecting high power. The scale correlated highly with the HPS among 514 undergraduates. The studies rely on self-ratings of manic temperament and dominance constructs, and findings have not yet been generalized to a clinical sample. Taken together, results support the hypothesis that manic temperament is related to a focus on achieving social dominance, ambitions related to achieving social recognition, perceptions of having achieved power, tendencies to experience dominance-related pride, and engagement in social behaviors consistent with this elevated sense of power. Copyright © 2012 Elsevier B.V. All rights reserved.

  18. THE DISK-WIND-JET CONNECTION IN THE BLACK HOLE H 1743-322

    Energy Technology Data Exchange (ETDEWEB)

    Miller, J. M.; King, A. L. [Department of Astronomy, University of Michigan, 500 Church Street, Ann Arbor, MI 48109-1042 (United States); Raymond, J. [Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Fabian, A. C. [Institute of Astronomy, University of Cambridge, Madingley Road, Cambridge CB3 OHA (United Kingdom); Reynolds, C. S. [Department of Astronomy, University of Maryland, College Park, MD 20742 (United States); Kallman, T. R. [Laboratory for High Energy Astrophysics, NASA Goddard Space Flight Center, Code 662, Greenbelt, MD 20771 (United States); Cackett, E. M. [Department of Physics and Astronomy, Wayne State University, 666 West Hancock Street, Detroit, MI 48201 (United States); Van der Klis, M. [Astronomical Institute ' Anton Pannekoek' , University of Amsterdam, Science Park 904, 1098-XH, Amsterdam (Netherlands); Steeghs, D. T. H., E-mail: jonmm@umich.edu [Department of Physics, University of Warwick, Coventry CV4 7AL (United Kingdom)

    2012-11-01

    X-ray disk winds are detected in spectrally soft, disk-dominated phases of stellar-mass black hole outbursts. In contrast, compact, steady, relativistic jets are detected in spectrally hard states that are dominated by non-thermal X-ray emission. Although these distinctive outflows appear to be almost mutually exclusive, it is possible that a disk wind persists in hard states but cannot be detected via X-ray absorption lines owing to very high ionization. Here, we present an analysis of a deep, 60 ks Chandra/HETGS observation of the black hole candidate H 1743-322 in the low/hard state. The spectrum shows no evidence of a disk wind, with tight limits, and within the range of ionizing flux levels that were measured in prior Chandra observations wherein a wind was clearly detected. In H 1743-322, at least, disk winds are actually diminished in the low/hard state, and disk winds and jets are likely state dependent and anti-correlated. These results suggest that although the launching radii of winds and jets may differ by orders of magnitude, they may both be tied to a fundamental property of the inner accretion flow, such as the mass accretion rate and/or the magnetic field topology of the disk. We discuss these results in the context of disk winds and jets in other stellar-mass black holes, and possible launching mechanisms for black hole outflows.

  19. THE DISK-WIND-JET CONNECTION IN THE BLACK HOLE H 1743–322

    International Nuclear Information System (INIS)

    Miller, J. M.; King, A. L.; Raymond, J.; Fabian, A. C.; Reynolds, C. S.; Kallman, T. R.; Cackett, E. M.; Van der Klis, M.; Steeghs, D. T. H.

    2012-01-01

    X-ray disk winds are detected in spectrally soft, disk-dominated phases of stellar-mass black hole outbursts. In contrast, compact, steady, relativistic jets are detected in spectrally hard states that are dominated by non-thermal X-ray emission. Although these distinctive outflows appear to be almost mutually exclusive, it is possible that a disk wind persists in hard states but cannot be detected via X-ray absorption lines owing to very high ionization. Here, we present an analysis of a deep, 60 ks Chandra/HETGS observation of the black hole candidate H 1743–322 in the low/hard state. The spectrum shows no evidence of a disk wind, with tight limits, and within the range of ionizing flux levels that were measured in prior Chandra observations wherein a wind was clearly detected. In H 1743–322, at least, disk winds are actually diminished in the low/hard state, and disk winds and jets are likely state dependent and anti-correlated. These results suggest that although the launching radii of winds and jets may differ by orders of magnitude, they may both be tied to a fundamental property of the inner accretion flow, such as the mass accretion rate and/or the magnetic field topology of the disk. We discuss these results in the context of disk winds and jets in other stellar-mass black holes, and possible launching mechanisms for black hole outflows.

  20. Control of radial propagation and polarity in a plasma jet in surrounding Ar

    KAUST Repository

    Gong, W.

    2018-01-08

    In recent years, the use of shielding gas to prevent the diffusion of the ambient air, particularly oxygen and nitrogen species, into the effluent of the atmospheric pressure plasma jet, and thus control the nature of chemical species used in the plasma treatment has increased. In this paper, the radial propagation of a plasma jet in ambient Ar is examined to find the key determinants of the polarity of plasma jets. The dynamics of the discharge reveal that the radial diffusion discharge is a special phenomenon observed only at the falling edge of the pulses. The radial transport of electrons, which is driven by the radial component of the applied electric field at the falling edge of the pulse, is shown to play an important role in increasing the seed electron density in the surrounding Ar. This result suggests a method to provide seed electrons at atmospheric pressure with a negative discharge. The polarity of the plasma jet is found to be determined by the pulse width rather than the polarity of the applied voltage, as it dictates the relative difference in the intensity of the two discharges in a single pulse, where the stronger discharge in a pulse dominates the behavior of the plasma jet. Accordingly, a method to control the polarity of a plasma jet through varying the pulse width is developed. Since plasma jets of different polarities differ remarkably in terms of their characteristics, the method to control the polarity reported in this paper will be of use for such applications as plasma-enhanced processing of materials and plasma biomedicine.

  1. Flow transition criteria of a liquid jet into a liquid pool

    Energy Technology Data Exchange (ETDEWEB)

    Saito, Shimpei, E-mail: s1630195@u.tsukuba.ac.jp [Graduate School of Systems and Information Engineering, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Abe, Yutaka [Faculty of Engineering, Information and Systems, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Koyama, Kazuya [Reactor Core and Safety Design Department, Mitsubishi FBR Systems, Inc., 2-34-17 Jingumae, Shibuya, Tokyo 150-0001 (Japan)

    2017-04-15

    Highlights: • Jet breakup and droplet formation in immiscible liquid-liquid systems was studied experimentally. • The observed jet breakup behavior was classified into characteristic regimes. • The droplet size distribution was analyzed using image processing. • The variation of droplet size was compared with available melt-jet experiments. • Extrapolation to the expected SFR conditions implied that most of the hydrodynamic conditions would be the atomization regime. - Abstract: To better understand the fundamental interactions between melt jet and coolant during a core-disruptive accident at a sodium-cooled fast reactor, the jet breakup and droplet formation in immiscible liquid-liquid systems were studied experimentally. Experiments using two different pairs of test fluids were carried out at isothermal conditions. The observed jet breakup behavior was classified into characteristic regimes based on the classical Ohnesorge classification in liquid-gas systems. The variation in breakup length obtained in the present liquid-liquid system was similar to that in a liquid-gas system. The droplet size distribution in each breakup regime was analyzed using image processing and droplet formation via pinch-off, satellite formation, and entrainment was observed. The measured droplet size was compared with those available from melt jet experiments. Based on the observation and analysis results, the breakup regimes were organized on a dimensionless operating diagram, with the derived correlations representing the criteria for regime boundaries of a liquid-liquid system. Finally, the experimental data were extrapolated to the expected conditions of a sodium-cooled fast reactor. From this, it was implied that most of the hydrodynamic conditions during an accident would be close to the atomization regime, in which entrainment is the dominant process for droplet formation.

  2. Significance of shock structure on supersonic jet mixing noise of axisymmetric nozzles

    Science.gov (United States)

    Kim, Chan M.; Krejsa, Eugene A.; Khavaran, Abbas

    1994-09-01

    One of the key technical elements in NASA's high speed research program is reducing the noise level to meet the federal noise regulation. The dominant noise source is associated with the supersonic jet discharged from the engine exhaust system. Whereas the turbulence mixing is largely responsible for the generation of the jet noise, a broadband shock-associated noise is also generated when the nozzle operates at conditions other than its design. For both mixing and shock noise components, because the source of the noise is embedded in the jet plume, one can expect that jet noise can be predicted from the jet flowfield computation. Mani et al. developed a unified aerodynamic/acoustic prediction scheme by applying an extension of Reichardt's aerodynamic model to compute turbulent shear stresses which are utilized in estimating the strength of the noise source. Although this method produces a fast and practical estimate of the jet noise, a modification by Khavaran et al. has led to an improvement in aerodynamic solution. The most notable feature in this work is that Reichardt's model is replaced with the computational fluid dynamics (CFD) solution of Reynolds-averaged Navier-Stokes equations. The major advantage of this work is that the essential, noise-related flow quantities such as turbulence intensity and shock strength can be better predicted. The predictions were limited to a shock-free design condition and the effect of shock structure on the jet mixing noise was not addressed. The present work is aimed at investigating this issue. Under imperfectly expanded conditions the existence of the shock cell structure and its interaction with the convecting turbulence structure may not only generate a broadband shock-associated noise but also change the turbulence structure, and thus the strength of the mixing noise source. Failure in capturing shock structures properly could lead to incorrect aeroacoustic predictions.

  3. Control of radial propagation and polarity in a plasma jet in surrounding Ar

    Science.gov (United States)

    Gong, W.; Yue, Y.; Ma, F.; Yu, F.; Wan, J.; Nie, L.; Bazaka, K.; Xian, Y.; Lu, X.; Ostrikov, K.

    2018-01-01

    In recent years, the use of shielding gas to prevent the diffusion of the ambient air, particularly oxygen and nitrogen species, into the effluent of the atmospheric pressure plasma jet, and thus control the nature of chemical species used in the plasma treatment has increased. In this paper, the radial propagation of a plasma jet in ambient Ar is examined to find the key determinants of the polarity of plasma jets. The dynamics of the discharge reveal that the radial diffusion discharge is a special phenomenon observed only at the falling edge of the pulses. The radial transport of electrons, which is driven by the radial component of the applied electric field at the falling edge of the pulse, is shown to play an important role in increasing the seed electron density in the surrounding Ar. This result suggests a method to provide seed electrons at atmospheric pressure with a negative discharge. The polarity of the plasma jet is found to be determined by the pulse width rather than the polarity of the applied voltage, as it dictates the relative difference in the intensity of the two discharges in a single pulse, where the stronger discharge in a pulse dominates the behavior of the plasma jet. Accordingly, a method to control the polarity of a plasma jet through varying the pulse width is developed. Since plasma jets of different polarities differ remarkably in terms of their characteristics, the method to control the polarity reported in this paper will be of use for such applications as plasma-enhanced processing of materials and plasma biomedicine.

  4. Measurement of the k(T) distribution of particles in jets produced in pp collisions at sqrt(s)=1.96 TeV.

    Science.gov (United States)

    Aaltonen, T; Adelman, J; Akimoto, T; Alvarez González, B; Amerio, S; Amidei, D; Anastassov, A; Annovi, A; Antos, J; Apollinari, G; Apresyan, A; Arisawa, T; Artikov, A; Ashmanskas, W; Attal, A; Aurisano, A; Azfar, F; Azzurri, P; Badgett, W; Barbaro-Galtieri, A; Barnes, V E; Barnett, B A; Bartsch, V; Bauer, G; Beauchemin, P-H; Bedeschi, F; Beecher, D; Behari, S; Bellettini, G; Bellinger, J; Benjamin, D; Beretvas, A; Beringer, J; Bhatti, A; Binkley, M; Bisello, D; Bizjak, I; Blair, R E; Blocker, C; Blumenfeld, B; Bocci, A; Bodek, A; Boisvert, V; Bolla, G; Bortoletto, D; Boudreau, J; Boveia, A; Brau, B; Bridgeman, A; Brigliadori, L; Bromberg, C; Brubaker, E; Budagov, J; Budd, H S; Budd, S; Burke, S; Burkett, K; Busetto, G; Bussey, P; Buzatu, A; Byrum, K L; Cabrera, S; Calancha, C; Campanelli, M; Campbell, M; Canelli, F; Canepa, A; Carls, B; Carlsmith, D; Carosi, R; Carrillo, S; Carron, S; Casal, B; Casarsa, M; Castro, A; Catastini, P; Cauz, D; Cavaliere, V; Cavalli-Sforza, M; Cerri, A; Cerrito, L; Chang, S H; Chen, Y C; Chertok, M; Chiarelli, G; Chlachidze, G; Chlebana, F; Cho, K; Chokheli, D; Chou, J P; Choudalakis, G; Chuang, S H; Chung, K; Chung, W H; Chung, Y S; Chwalek, T; Ciobanu, C I; Ciocci, M A; Clark, A; Clark, D; Compostella, G; Convery, M E; Conway, J; Cordelli, M; Cortiana, G; Cox, C A; Cox, D J; Crescioli, F; Cuenca Almenar, C; Cuevas, J; Culbertson, R; Cully, J C; Dagenhart, D; Datta, M; Davies, T; de Barbaro, P; De Cecco, S; Deisher, A; De Lorenzo, G; Dell'orso, M; Deluca, C; Demortier, L; Deng, J; Deninno, M; Derwent, P F; di Giovanni, G P; Dionisi, C; Di Ruzza, B; Dittmann, J R; D'Onofrio, M; Donati, S; Dong, P; Donini, J; Dorigo, T; Dube, S; Efron, J; Elagin, A; Erbacher, R; Errede, D; Errede, S; Eusebi, R; Fang, H C; Farrington, S; Fedorko, W T; Feild, R G; Feindt, M; Fernandez, J P; Ferrazza, C; Field, R; Flanagan, G; Forrest, R; Frank, M J; Franklin, M; Freeman, J C; Furic, I; Gallinaro, M; Galyardt, J; Garberson, F; Garcia, J E; Garfinkel, A F; Genser, K; Gerberich, H; Gerdes, D; Gessler, A; Giagu, S; Giakoumopoulou, V; Giannetti, P; Gibson, K; Gimmell, J L; Ginsburg, C M; Giokaris, N; Giordani, M; Giromini, P; Giunta, M; Giurgiu, G; Glagolev, V; Glenzinski, D; Gold, M; Goldschmidt, N; Golossanov, A; Gomez, G; Gomez-Ceballos, G; Goncharov, M; González, O; Gorelov, I; Goshaw, A T; Goulianos, K; Gresele, A; Grinstein, S; Grosso-Pilcher, C; Grundler, U; Guimaraes da Costa, J; Gunay-Unalan, Z; Haber, C; Hahn, K; Hahn, S R; Halkiadakis, E; Han, B-Y; Han, J Y; Happacher, F; Hara, K; Hare, D; Hare, M; Harper, S; Harr, R F; Harris, R M; Hartz, M; Hatakeyama, K; Hays, C; Heck, M; Heijboer, A; Heinrich, J; Henderson, C; Herndon, M; Heuser, J; Hewamanage, S; Hidas, D; Hill, C S; Hirschbuehl, D; Hocker, A; Hou, S; Houlden, M; Hsu, S-C; Huffman, B T; Hughes, R E; Husemann, U; Hussein, M; Husemann, U; Huston, J; Incandela, J; Introzzi, G; Iori, M; Ivanov, A; James, E; Jayatilaka, B; Jeon, E J; Jha, M K; Jindariani, S; Johnson, W; Jones, M; Joo, K K; Jun, S Y; Jung, J E; Junk, T R; Kamon, T; Kar, D; Karchin, P E; Kato, Y; Kephart, R; Keung, J; Khotilovich, V; Kilminster, B; Kim, D H; Kim, H S; Kim, H W; Kim, J E; Kim, M J; Kim, S B; Kim, S H; Kim, Y K; Kimura, N; Kirsch, L; Klimenko, S; Knuteson, B; Ko, B R; Kondo, K; Kong, D J; Konigsberg, J; Korytov, A; Kotwal, A V; Kreps, M; Kroll, J; Krop, D; Krumnack, N; Kruse, M; Krutelyov, V; Kubo, T; Kuhr, T; Kulkarni, N P; Kurata, M; Kwang, S; Laasanen, A T; Lami, S; Lammel, S; Lancaster, M; Lander, R L; Lannon, K; Lath, A; Latino, G; Lazzizzera, I; Lecompte, T; Lee, E; Lee, H S; Lee, S W; Leone, S; Lewis, J D; Lin, C-S; Linacre, J; Lindgren, M; Lipeles, E; Lister, A; Litvintsev, D O; Liu, C; Liu, T; Lockyer, N S; Loginov, A; Loreti, M; Lovas, L; Lucchesi, D; Luci, C; Lueck, J; Lujan, P; Lukens, P; Lungu, G; Lyons, L; Lys, J; Lysak, R; Macqueen, D; Madrak, R; Maeshima, K; Makhoul, K; Maki, T; Maksimovic, P; Malde, S; Malik, S; Manca, G; Manousakis-Katsikakis, A; Margaroli, F; Marino, C; Marino, C P; Martin, A; Martin, V; Martínez, M; Martínez-Ballarín, R; Maruyama, T; Mastrandrea, P; Masubuchi, T; Mathis, M; Mattson, M E; Mazzanti, P; McFarland, K S; McIntyre, P; McNulty, R; Mehta, A; Mehtala, P; Menzione, A; Merkel, P; Mesropian, C; Miao, T; Miladinovic, N; Miller, R; Mills, C; Milnik, M; Mitra, A; Mitselmakher, G; Miyake, H; Moggi, N; Moon, C S; Moore, R; Morello, M J; Morlok, J; Movilla Fernandez, P; Mülmenstädt, J; Mukherjee, A; Muller, Th; Mumford, R; Murat, P; Mussini, M; Nachtman, J; Nagai, Y; Nagano, A; Naganoma, J; Nakamura, K; Nakano, I; Napier, A; Necula, V; Nett, J; Neu, C; Neubauer, M S; Neubauer, S; Nielsen, J; Nodulman, L; Norman, M; Norniella, O; Nurse, E; Oakes, L; Oh, S H; Oh, Y D; Oksuzian, I; Okusawa, T; Orava, R; Pagan Griso, S; Palencia, E; Papadimitriou, V; Papaikonomou, A; Paramonov, A A; Parks, B; Pashapour, S; Patrick, J; Pauletta, G; Paulini, M; Paus, C; Peiffer, T; Pellett, D E; Penzo, A; Phillips, T J; Piacentino, G; Pianori, E; Pinera, L; Pitts, K; Plager, C; Pondrom, L; Poukhov, O; Pounder, N; Prakoshyn, F; Pronko, A; Proudfoot, J; Ptohos, F; Pueschel, E; Punzi, G; Pursley, J; Rademacker, J; Rahaman, A; Ramakrishnan, V; Ranjan, N; Redondo, I; Renton, P; Renz, M; Rescigno, M; Richter, S; Rimondi, F; Ristori, L; Robson, A; Rodrigo, T; Rodriguez, T; Rogers, E; Rolli, S; Roser, R; Rossi, M; Rossin, R; Roy, P; Ruiz, A; Russ, J; Rusu, V; Safonov, A; Sakumoto, W K; Saltó, O; Santi, L; Sarkar, S; Sartori, L; Sato, K; Savoy-Navarro, A; Schlabach, P; Schmidt, A; Schmidt, E E; Schmidt, M A; Schmidt, M P; Schmitt, M; Schwarz, T; Scodellaro, L; Scribano, A; Scuri, F; Sedov, A; Seidel, S; Seiya, Y; Semenov, A; Sexton-Kennedy, L; Sforza, F; Sfyrla, A; Shalhout, S Z; Shears, T; Shepard, P F; Shimojima, M; Shiraishi, S; Shochet, M; Shon, Y; Shreyber, I; Sidoti, A; Sinervo, P; Sisakyan, A; Slaughter, A J; Slaunwhite, J; Sliwa, K; Smith, J R; Snider, F D; Snihur, R; Soha, A; Somalwar, S; Sorin, V; Spalding, J; Spreitzer, T; Squillacioti, P; Stanitzki, M; St Denis, R; Stelzer, B; Stelzer-Chilton, O; Stentz, D; Strologas, J; Strycker, G L; Stuart, D; Suh, J S; Sukhanov, A; Suslov, I; Suzuki, T; Taffard, A; Takashima, R; Takeuchi, Y; Tanaka, R; Tecchio, M; Teng, P K; Terashi, K; Thom, J; Thompson, A S; Thompson, G A; Thomson, E; Tipton, P; Ttito-Guzmán, P; Tkaczyk, S; Toback, D; Tokar, S; Tollefson, K; Tomura, T; Tonelli, D; Torre, S; Torretta, D; Totaro, P; Tourneur, S; Trovato, M; Tsai, S-Y; Tu, Y; Turini, N; Ukegawa, F; Vallecorsa, S; van Remortel, N; Varganov, A; Vataga, E; Vázquez, F; Velev, G; Vellidis, C; Veszpremi, V; Vidal, M; Vidal, R; Vila, I; Vilar, R; Vine, T; Vogel, M; Volobouev, I; Volpi, G; Wagner, P; Wagner, R G; Wagner, R L; Wagner, W; Wagner-Kuhr, J; Wakisaka, T; Wallny, R; Wang, S M; Warburton, A; Waters, D; Weinberger, M; Weinelt, J; Wester, W C; Whitehouse, B; Whiteson, D; Wicklund, A B; Wicklund, E; Wilbur, S; Williams, G; Williams, H H; Wilson, P; Winer, B L; Wittich, P; Wolbers, S; Wolfe, C; Wright, T; Wu, X; Würthwein, F; Wynne, S M; Xie, S; Yagil, A; Yamamoto, K; Yamaoka, J; Yang, U K; Yang, Y C; Yao, W M; Yeh, G P; Yoh, J; Yorita, K; Yoshida, T; Yu, G B; Yu, I; Yu, S S; Yun, J C; Zanello, L; Zanetti, A; Zhang, X; Zheng, Y; Zucchelli, S

    2009-06-12

    We present a measurement of the transverse momentum with respect to the jet axis (k(t)) of particles in jets produced in pp collisions at sqrt(s)=1.96 TeV. Results are obtained for charged particles in a cone of 0.5 radians around the jet axis in events with dijet invariant masses between 66 and 737 GeV/c(2). The experimental data are compared to theoretical predictions obtained for fragmentation partons within the framework of resummed perturbative QCD using the modified leading log and next-to-modified leading log approximations. The comparison shows that trends in data are successfully described by the theoretical predictions, indicating that the perturbative QCD stage of jet fragmentation is dominant in shaping basic jet characteristics.

  5. Multi-jet merged top-pair production including electroweak corrections

    Science.gov (United States)

    Gütschow, Christian; Lindert, Jonas M.; Schönherr, Marek

    2018-04-01

    We present theoretical predictions for the production of top-quark pairs in association with jets at the LHC including electroweak (EW) corrections. First, we present and compare differential predictions at the fixed-order level for t\\bar{t} and t\\bar{t}+ {jet} production at the LHC considering the dominant NLO EW corrections of order O(α_{s}^2 α ) and O(α_{s}^3 α ) respectively together with all additional subleading Born and one-loop contributions. The NLO EW corrections are enhanced at large energies and in particular alter the shape of the top transverse momentum distribution, whose reliable modelling is crucial for many searches for new physics at the energy frontier. Based on the fixed-order results we motivate an approximation of the EW corrections valid at the percent level, that allows us to readily incorporate the EW corrections in the MePs@Nlo framework of Sherpa combined with OpenLoops. Subsequently, we present multi-jet merged parton-level predictions for inclusive top-pair production incorporating NLO QCD + EW corrections to t\\bar{t} and t\\bar{t}+ {jet}. Finally, we compare at the particle-level against a recent 8 TeV measurement of the top transverse momentum distribution performed by ATLAS in the lepton + jet channel. We find very good agreement between the Monte Carlo prediction and the data when the EW corrections are included.

  6. Photon-tagged and B-meson-tagged b-jet production at the LHC

    Directory of Open Access Journals (Sweden)

    Jinrui Huang

    2015-11-01

    Full Text Available Tagged jet measurements in high energy hadronic and nuclear reactions provide constraints on the energy and parton flavor origin of the parton shower that recoils against the tagging particle. Such additional insight can be especially beneficial in illuminating the mechanisms of heavy flavor production in proton–proton collisions at the LHC and their modification in the heavy ion environment, which are not fully understood. With this motivation, we present theoretical results for isolated-photon-tagged and B-meson-tagged b-jet production at sNN=5.1 TeV for comparison to the upcoming lead–lead data. We find that photon-tagged b-jets exhibit smaller momentum imbalance shift in nuclear matter, and correspondingly smaller energy loss, than photon-tagged light flavor jets. Our results show that B-meson tagging is most effective in ensuring that the dominant fraction of recoiling jets originate from prompt b-quarks. Interestingly, in this channel the large suppression of the cross section is not accompanied by a significant momentum imbalance shift.

  7. Commercial and industrial applications of color ink jet: a technological perspective

    Science.gov (United States)

    Dunand, Alain

    1996-03-01

    In just 5 years, color ink-jet has become the dominant technology for printing color images and graphics in the office and home markets. In commercial printing, the traditional printing processes are being influenced by new digital techniques. Color ink-jet proofing, and concepts such as computer to film/plate or digital processes are contributing to the evolution of the industry. In industrial color printing, the penetration of digital techniques is just beginning. All widely used conventional contact printing technologies involve mechanical printing forms including plates, screens or engraved cylinders. Such forms, which need to be newly created and set up for each job, increase costs. In our era of fast changing customer demands, growing needs for customization, and increasing use of digital exchange of information, the commercial and industrial printing markets represent an enormous potential for digital printing technologies. The adoption characteristics for the use of color ink-jet in these industries are discussed. Examples of color ink-jet applications in the fields of billboard printing, floor/wall covering decoration, and textile printing are described. The requirements on print quality, productivity, reliability, substrate compatibility, and color lead to the consideration of various types of ink-jet technologies. Key technical enabling factors and directions for future improvements are presented.

  8. The Shock Dynamics of Heterogeneous YSO Jets: 3D Simulations Meet Multi-epoch Observations

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, E. C.; Frank, A. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627-0171 (United States); Hartigan, P. [Department of Physics and Astronomy, Rice University, 6100 S. Main, Houston, TX 77521-1892 (United States); Lebedev, S. V. [Blackett Laboratory, Imperial College London, Prince Consort Road, London SW7 2BW (United Kingdom)

    2017-03-10

    High-resolution observations of young stellar object (YSO) jets show them to be composed of many small-scale knots or clumps. In this paper, we report results of 3D numerical simulations designed to study how such clumps interact and create morphologies and kinematic patterns seen in emission line observations. Our simulations focus on clump scale dynamics by imposing velocity differences between spherical, over-dense regions, which then lead to the formation of bow shocks as faster clumps overtake slower material. We show that much of the spatial structure apparent in emission line images of jets arises from the dynamics and interactions of these bow shocks. Our simulations show a variety of time-dependent features, including bright knots associated with Mach stems where the shocks intersect, a “frothy” emission structure that arises from the presence of the Nonlinear Thin Shell Instability along the surfaces of the bow shocks, and the merging and fragmentation of clumps. Our simulations use a new non-equilibrium cooling method to produce synthetic emission maps in H α and [S ii]. These are directly compared to multi-epoch Hubble Space Telescope observations of Herbig–Haro jets. We find excellent agreement between features seen in the simulations and the observations in terms of both proper motion and morphologies. Thus we conclude that YSO jets may be dominated by heterogeneous structures and that interactions between these structures and the shocks they produce can account for many details of YSO jet evolution.

  9. Expanded R&D by Jet-engine-steering Revolution

    Science.gov (United States)

    Gal-Or, Benjamin

    2017-11-01

    Since 1987 [1,2,3,4,5] the global jet engine community is facing the historical fact that jet engine steering is gradually replacing canards and the common, often dangerous and obsolete, aerodynamic-only flight control - a fact that (i) has already affected the defense-industrial complex in the US, Russia, China, Japan, S-Korea and India, (ii) has integrated the traditional jet-engine components R&D with advanced aero-electro-physics, stealth technology, thrust vectoring aerodynamics and material science. Moreover, this military revolution is historically due to expand into the civil transport jets domain, [6,7,8,9]. The historical aim of the JES-Revolution remains the same: Replace the common, stall-spin sensitive canards [6] and Aerodynamic-Only-Obsolete-Flight Control ("AOOF Control"). Invented about 100 years ago for propeller-driven air vehicles, it has already been partially replaced for failure to function in WVR-combat post-stall domain, and for the following reasons: In comparison with complete Tail-Less, Canard-Less, Stealth-JES (Figure 5 and References [1,2,3,4,5,6]), the common AOOF Control increases drag, weight, fuel consumption, complexity, cost, and reduces flight safety, stealth, [Low Detectability] and provides zero post-stall, WVR air combat capability while its CANARDS KILL LD & REDUCE JES. Examples of stealth fighter aircraft that have already replaced canards and AOOF-Control where JES provides at least 64 to 0 KILL-RATIO advantage over AOOF-Controlled conventional fighter aircraft: The U.S. JES F-22 and, apparently, the Russian JES-Su-T-50 & 35S, China 2016-J-31, Indian HAL AMCA & FGFA, Japanese JES IHHI ATD-X, S-Korean JES KF-X. Cf. X-44 in Figure 5. Consequently, the jet engine is no longer defined as providing only brute force forward. Instead, it successfully competes with and wins over the wrong, dominating AOOF-Control, at least as a backup flight control whose sole factual domain is currently a well-established, primary flight

  10. SYNTHETIC JET APPLIED TO DETECT POTENTIAL TERRORISTS

    Czech Academy of Sciences Publication Activity Database

    Tesař, Václav; Peszyński, K.

    2010-01-01

    Roč. 5, č. 3 (2010), s. 229-234 ISSN 1231-3998 R&D Projects: GA AV ČR IAA200760705; GA ČR GA101/07/1499 Institutional research plan: CEZ:AV0Z20760514 Keywords : synthetic jets * annular jets * terrorism Subject RIV: BK - Fluid Dynamics

  11. Jet diffusion in stagnant ambient fluid

    NARCIS (Netherlands)

    Abraham, G.

    1963-01-01

    Submarine outfall disposal of domestic and industrial sewage is a method of disposal of steadily growing importance. The flow from an ocean outfall is essentially that of a submerged horizontal or vertical jet. Thus a study of the hydrodynamics of such jets is needed to evaluate the dilution of the

  12. AGN feedback compared: jets versus radiation

    Science.gov (United States)

    Cielo, Salvatore; Bieri, Rebekka; Volonteri, Marta; Wagner, Alexander Y.; Dubois, Yohan

    2018-06-01

    Feedback by active galactic nuclei (AGNs) is often divided into quasar and radio mode, powered by radiation or radio jets, respectively. Both are fundamental in galaxy evolution, especially in late-type galaxies, as shown by cosmological simulations and observations of jet-ISM (interstellar medium) interactions in these systems. We compare AGN feedback by radiation and by collimated jets through a suite of simulations, in which a central AGN interacts with a clumpy, fractal galactic disc. We test AGNs of 1043 and 1046 erg s-1, considering jets perpendicular or parallel to the disc. Mechanical jets drive the more powerful outflows, exhibiting stronger mass and momentum coupling with the dense gas, while radiation heats and rarefies the gas more. Radiation and perpendicular jets evolve to be quite similar in outflow properties and effect on the cold ISM, while inclined jets interact more efficiently with all the disc gas, removing the densest 20 {per cent} in 20 Myr, and thereby reducing the amount of cold gas available for star formation. All simulations show small-scale inflows of 0.01-0.1 M⊙ yr-1, which can easily reach down to the Bondi radius of the central supermassive black hole (especially for radiation and perpendicular jets), implying that AGNs modulate their own duty cycle in a feedback/feeding cycle.

  13. Jets. The materialisation of quarks and gluons

    International Nuclear Information System (INIS)

    Marshall, R.

    1985-09-01

    The paper, which is aimed at scientists outside the immediate field of particle physics, describes some of the properties of jets and how the jet observables can be related to quark parameters. The similarity of quark and leptons is underlined. (author)

  14. Scaling behavior of jet production at CDF

    International Nuclear Information System (INIS)

    Behrends, S.

    1992-11-01

    Inclusive jet cross-sections have been measured in bar pp collisions at √s = 546 and 1800 GeV, using the CDF detector at the Fermilab Tevatron. The ratio of jet cross-sections is compared to predictions from simple scaling and 0(α s 3 ) QCD

  15. The jet membrane experiment: downstream sampling

    International Nuclear Information System (INIS)

    Campargue, R.

    1976-01-01

    This review lecture is devoted to an invasion separation effect through a free jet structure, found in 1966 at Saclay and used as the basis for an initial French patent on the separation of gas molecules of different masses. It operates by the differential penetration of a gas or isotopic mixture into the structure of a free jet

  16. Production of jet fuel from alternative source

    Energy Technology Data Exchange (ETDEWEB)

    Eller, Zoltan; Papp, Anita; Hancsok, Jenoe [Pannonia Univ., Veszprem (Hungary). MOL Dept. of Hydrocarbon and Coal Processing

    2013-06-01

    Recent demands for low aromatic content jet fuels have shown significant increase in the last 20 years. This was generated by the growing of aviation. Furthermore, the quality requirements have become more aggravated for jet fuels. Nowadays reduced aromatic hydrocarbon fractions are necessary for the production of jet fuels with good burning properties, which contribute to less harmful material emission. In the recent past the properties of gasolines and diesel gas oils were continuously severed, and the properties of jet fuels will be more severe, too. Furthermore, it can become obligatory to blend alternative components into jet fuels. With the aromatic content reduction there is a possibility to produce high energy content jet fuels with the desirable properties. One of the possibilities is the blending of biocomponents from catalytic hydrogenation of triglycerides. Our aim was to study the possibilities of producing low sulphur and aromatic content jet fuels in a catalytic way. On a CoMo/Al{sub 2}O{sub 3} catalyst we studied the possibilities of quality improving of a kerosene fraction and coconut oil mixture depending on the change of the process parameters (temperature, pressure, liquid hourly space velocity, volume ratio). Based on the quality parameters of the liquid products we found that we made from the feedstock in the adequate technological conditions products which have a high smoke point (> 35 mm) and which have reduced aromatic content and high paraffin content (90%), so these are excellent jet fuels, and their stack gases damage the environment less. (orig.)

  17. Delayed Capillary Breakup of Falling Viscous Jets

    NARCIS (Netherlands)

    Javadi, A.; Eggers, J.; Bonn, D.; Habibi, M.; Ribe, N.M.

    2013-01-01

    Thin jets of viscous fluid like honey falling from capillary nozzles can attain lengths exceeding 10 m before breaking up into droplets via the Rayleigh-Plateau (surface tension) instability. Using a combination of laboratory experiments and WKB analysis of the growth of shape perturbations on a jet

  18. Study of type III ELMs in JET

    NARCIS (Netherlands)

    Sartori, R.; Saibene, G.; Horton, L. D.; Becoulet, M.; Budny, R.; Borba, D.; Chankin, A.; Conway, G. D.; Cordey, G.; McDonald, D.; Guenther, K.; von Hellermann, M. G.; Igithkanov, Y.; Loarte, A.; Lomas, P. J.; Pogutse, O.; Rapp, J.

    2004-01-01

    This paper presents the results of JET experiments aimed at studying the operational space of plasmas with a Type III ELMy edge, in terms of both local and global plasma parameters. In JET, the Type III ELMy regime has a wide operational space in the pedestal n(e)-T-e diagram, and Type III ELMs are

  19. Multiplicities of Hadrons Within Jets at STAR

    Science.gov (United States)

    Wheeler, Suzanne; Drachenberg, Jim; STAR Collaboration

    2017-09-01

    Jet measurements have long been tools used to understand QCD phenomena. There is still much to be learned from the production of hadrons inside of jets. In particular, hadron yields within jets from proton-proton collisions have been proposed as a way to unearth more information on gluon fragmentation functions. In 2011, the STAR experiment at RHIC collected 23 pb-1 of data from proton-proton collisions at √{ s} = 500 GeV. The jets of most interest for gluon fragmentation functions are those with transverse momentum around 6-15 GeV/c. Large acceptance charged particle tracking and electromagnetic calorimetry make STAR an excellent jet detector. Time-of-flight and specific energy loss in the tracking system allow particle identification on the various types of hadrons within the jets, e.g., distinguishing pions from kaons and protons. An integral part of analyzing the data collected is understanding how the finite resolutions of the various detector subsystems influence the measured jet and hadron kinematics. For this reason, Monte Carlo simulations can be used to track the shifting of the hadron and jet kinematics between the generator level and the detector reconstruction level. The status of this analysis will be presented. We would like to acknowledge the Ronald E. McNair program for supporting this research.

  20. First measurement of ECE from JET

    International Nuclear Information System (INIS)

    Costley, A.E.; Bartlett, D.V.; Campbell, D.J.; Baker, E.A.M.; Kiff, M.G.; Neill, G.F.

    1985-01-01

    A multichannel system for measuring the electron cyclotron emission from JET has been designed and constructed. The design criteria are briefly outlined and the system is described. Some typical results obtained with the first operational channel during the november-december 1983 operating period of JET are presented

  1. Jet substructure measurements at ATLAS and CMS

    CERN Document Server

    Dattagupta, Aparajita; The ATLAS collaboration

    2017-01-01

    A review is given of recent Run II measurements of jet substructure at CMS and ATLAS, as well of the most relevant measurements from Run I. Quark and gluon discrimination, jet mass and other substructure observable are discussed together with prospects for future measurements with new insight from theory.

  2. Scaling behavior of jet production at CDF

    Energy Technology Data Exchange (ETDEWEB)

    Behrends, S. [Brandeis Univ., Waltham, MA (United States). Dept. of Physics; The CDF Collaboration

    1992-11-01

    Inclusive jet cross-sections have been measured in {bar p}p collisions at {radical}s = 546 and 1800 GeV, using the CDF detector at the Fermilab Tevatron. The ratio of jet cross-sections is compared to predictions from simple scaling and 0({alpha}{sub s{sup 3}}) QCD.

  3. AGN Feedback Compared: Jets versus Radiation

    Science.gov (United States)

    Cielo, Salvatore; Bieri, Rebekka; Volonteri, Marta; Wagner, Alexander Y.; Dubois, Yohan

    2018-03-01

    Feedback by Active Galactic Nuclei is often divided into quasar and radio mode, powered by radiation or radio jets, respectively. Both are fundamental in galaxy evolution, especially in late-type galaxies, as shown by cosmological simulations and observations of jet-ISM interactions in these systems. We compare AGN feedback by radiation and by collimated jets through a suite of simulations, in which a central AGN interacts with a clumpy, fractal galactic disc. We test AGN of 1043 and 1046 erg/s, considering jets perpendicular or parallel to the disc. Mechanical jets drive the more powerful outflows, exhibiting stronger mass and momentum coupling with the dense gas, while radiation heats and rarifies the gas more. Radiation and perpendicular jets evolve to be quite similar in outflow properties and effect on the cold ISM, while inclined jets interact more efficiently with all the disc gas, removing the densest 20% in 20 Myr, and thereby reducing the amount of cold gas available for star formation. All simulations show small-scale inflows of 0.01 - 0.1 M⊙/yr, which can easily reach down to the Bondi radius of the central supermassive black hole (especially for radiation and perpendicular jets), implying that AGN modulate their own duty cycle in a feedback/feeding cycle.

  4. Investigation of Jet Noise Using Optical Holography

    Science.gov (United States)

    1973-04-01

    Holographic interferograms have been made of cold, laboratory scale, supersonic air and nitrogen jet in the mach number range of 2.1 ot 3.4, and of helium jets in the mach number range of 1.5 to 2.95. These holograms demonstrate that the acoustic fie...

  5. Dynamics of runaways in JET

    International Nuclear Information System (INIS)

    Gill, R.D.; Alper, B.; Edwards, A.W.; Ingesson, L.C.; Johnson, M.F.; Ward, D.

    2001-01-01

    Measurements are presented of the properties of the runaway beams generated in JET following disruptions. Radiation is emitted by the runaways, both when they are in flight and when they hit the vessel walls. Because radiation protected soft x-ray cameras were developed for the JET DT campaign, it has been possible to make the first direct observations of the runaway beam in flight from the x-ray line radiation produced by the beam excitation of K-shell vacancies in the metallic impurities of the residual plasma. These observations give clear images of the runaway beam and provide detailed information on its time development, size, position and stability. The current density and q-profile have also been determined. It has been found that there is a delay between the disruption and the start of runaway generation and this offers a possibility of instigating runaway control methods. Detailed determination of the runaway-wall interaction suggests that the runaways have a braided structure. (author)

  6. Jet-associated resonance spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Englert, Christoph [University of Glasgow, SUPA, School of Physics and Astronomy, Glasgow (United Kingdom); Ferretti, Gabriele [Chalmers University of Technology, Department of Physics, Goeteborg (Sweden); Spannowsky, Michael [Durham University, Department of Physics, Institute for Particle Physics Phenomenology, Durham (United Kingdom)

    2017-12-15

    We present a model-independent study aimed at characterising the nature of possible resonances in the jet-photon or jet-Z final state at hadron colliders. Such resonances are expected in many models of compositeness and would be a clear indication of new physics. At leading order, in the narrow width approximation, the matrix elements are parameterised by just a few constants describing the coupling of the various helicities to the resonance. We present the full structure of such amplitudes up to spin 2 and use them to simulate relevant kinematic distributions that could serve to constrain the coupling structure. This also generalises the signal generation strategy that is currently pursued by ATLAS and CMS to the most general case in the considered channels. While the determination of the P/CP properties of the interaction seems to be out of reach within this framework, there is a wealth of information to be gained about the spin of the resonance and the relative couplings of the helicities. (orig.)

  7. Atmospheric-pressure plasma jet

    Science.gov (United States)

    Selwyn, Gary S.

    1999-01-01

    Atmospheric-pressure plasma jet. A .gamma.-mode, resonant-cavity plasma discharge that can be operated at atmospheric pressure and near room temperature using 13.56 MHz rf power is described. Unlike plasma torches, the discharge produces a gas-phase effluent no hotter than 250.degree. C. at an applied power of about 300 W, and shows distinct non-thermal characteristics. In the simplest design, two concentric cylindrical electrodes are employed to generate a plasma in the annular region therebetween. A "jet" of long-lived metastable and reactive species that are capable of rapidly cleaning or etching metals and other materials is generated which extends up to 8 in. beyond the open end of the electrodes. Films and coatings may also be removed by these species. Arcing is prevented in the apparatus by using gas mixtures containing He, which limits ionization, by using high flow velocities, and by properly shaping the rf-powered electrode. Because of the atmospheric pressure operation, no ions survive for a sufficiently long distance beyond the active plasma discharge to bombard a workpiece, unlike low-pressure plasma sources and conventional plasma processing methods.

  8. Experience with graphite in JET

    International Nuclear Information System (INIS)

    Pick, M.A.; Celentano, G.; Deksnis, E.; Dietz, K.J.; Shaw, R.; Sonnenberg, K.; Walravens, M.

    1987-01-01

    During the current operational period of JET more than 50% of the internal area of the machine is covered in graphite tiles. This includes the 15 m 2 of carbon tiles installed in the new toroidal limiter, the 40 poloidal belts of graphite tiles covering the U-joints and bellows as well as a two metre high ring (-- 20 m 2 ) or carbon tiles on the inner wall of the Torus. A ring of tiles in the equatorial plane (3 tiles high) consists of carbon-carbon fibre tiles. Test bed results indicated that the fine grained graphite tiles cracked at ∼ 1 kW/cm 2 for 2s of irradiation whereas the carbon-carbon fibre tiles were able to sustain a flux, limited by the irradiation facility, of 3.5 kW for 3s without any damage. The authors report on the generally positive experience they have had had with the installed graphite during the present and previous in-vessel configurations. This includes the physical integrity of the tiles under severe conditions such as high energy run-away electron beams, plasma disruptions and high heat fluxes. They report on the importance of the precise positioning of the inner wall and x-point tiles at the very high power fluxes of JET and the effect of deviations on both graphite and carbon-fibre tiles

  9. Relativistic jets in SS 433

    International Nuclear Information System (INIS)

    Margon, B.

    1982-01-01

    The most unusual characteristic of the star SS 433 emerged in the late 1970's when a series of optical spectra showed intense, broad optical emission lines whose profiles and wavelengths changed drastically from night to night. These features are interpreted as strong Doppler-shifted Balmer and HeI lines. The modulation of the Doppler shifts are observed as being cyclic with a period of about 164 days. It was hypothesized that these phenomena were caused by two collimated, colinear, jets which were ejecting in opposite directions from SS 433. Most authors believe that velocity variations of the emission lines are caused by a cyclic rotation of jet axis inclined to line of sight. This rotation being the result of precession, which leads one to suspect SS 433 as a member of a close binary system. This hypothesis has been confirmed from recent optical, radio, and x-ray observations which are discussed in the article. The combination of optical and radio observations of SS 433, described in the article, gives an accurate measure of the Kinematics of the system and some confidence that the Kinematic equations are understood. However, the specific physical processes of this ejection are poorly understood. Some theoretical difficulties regarding this are given

  10. Jet production in hardronic collisions

    International Nuclear Information System (INIS)

    Di Lella, L.

    1985-01-01

    An experiment was performed at the CERN Super Proton Synchrotron (SPS) using a calorimeter with full azimuthal coverage and subtending the interval of polar angles 45 0 0 in the center-of-mass frame. This experiment selected hadronic collisions depositing large amounts of energy in the calorimeter, and found that these final states consisted mostly of many low-rho/sub T/ particles distributed symmetrically in azimuth, in disagreement with the structure expected for high-rho/sub T/jets. The same conclusions were reached by a similar experiment. These negative results were in sharp contrast with the case of e/sup +/e/sup -/ annihilation into hadrons. The azimuthally symmetric structure of these events was interpreted either as the effect of multiple gluon bremsstrahlung from the initial-state partons; or as the effect of the tails of the multiplicity distributions in ordinary soft collisions. This pessimistic view has been contradicted by the dramatic emergence of unambiguous jets at the CERN pp-bar Collider. The purpose of this article is to review the main experimental results obtained recently on this subject, and to discuss their interpretation in the theoretical framework of QCD

  11. Lower hybrid launcher on JET

    International Nuclear Information System (INIS)

    Soeldner, F.X.; Brusati, M.; Ekedahl, A.

    1994-01-01

    Lower Hybrid current drive (LHCD) experiments were performed in JET in a first stage with one third of the final LHCD system. Good coupling with reflection coefficients as low as 1% and a power density of ∼4 kW/cm 2 on the plasma interface were obtained with the prototype launcher. The complete LHCD system with a total power of 12 MW (20 s) in the generator will start operation with the begin of JET divertor experiments in early 1994. The full launcher contains an array of 384 waveguides, built up from 48 multijunctions with internal power splitting. Three different LH wave spectra can be radiated simultaneously into the plasma, applying different phase settings to the three independent sections of the grill type antenna. test bed experiments have started on a new concept for a compact LH launcher, using a hyperguide as connection between an array of standard size waveguides and the plasma facing antenna structure which forms the slow wave LH spectrum. (author)

  12. Jet-associated resonance spectroscopy

    Science.gov (United States)

    Englert, Christoph; Ferretti, Gabriele; Spannowsky, Michael

    2017-12-01

    We present a model-independent study aimed at characterising the nature of possible resonances in the jet-photon or jet- Z final state at hadron colliders. Such resonances are expected in many models of compositeness and would be a clear indication of new physics. At leading order, in the narrow width approximation, the matrix elements are parameterised by just a few constants describing the coupling of the various helicities to the resonance. We present the full structure of such amplitudes up to spin 2 and use them to simulate relevant kinematic distributions that could serve to constrain the coupling structure. This also generalises the signal generation strategy that is currently pursued by ATLAS and CMS to the most general case in the considered channels. While the determination of the P/CP properties of the interaction seems to be out of reach within this framework, there is a wealth of information to be gained about the spin of the resonance and the relative couplings of the helicities.

  13. Monte Carlo study for the dynamical fluctuations inside a single jet in 2-jet events

    International Nuclear Information System (INIS)

    Zhang Kunshi; Liu Lianshou; Yin Jianwu; Chen Gang; Liu Chao

    2002-01-01

    The dynamical fluctuations inside a single jet in the 2-jet events produced in e + e - collisions at 91.2 GeV have been studied using Monte Carlo method. The results show that, the anisotropy of dynamical fluctuations inside a single jet changes remarkably with the variation of the cut parameter y cut . A transition point (γ p t = γ ψ ≠γ y ) exists, where the dynamical fluctuations are anisotropic in the longitudinal-transverse plan and isotropic in the transverse planes. It indicates that the y cut corresponding to the transition point is a physically reasonable cutting parameter for selecting jets and, meanwhile, the relative transverse momentum k t at the transition point is the scale for the determination of physical jets. This conclusion is in good agreement with the experimental fact that the third jet (gluon jet) was historically first discovered in the energy region 17-30 GeV in e + e - collisions

  14. More Jets in more LHC Searches

    CERN Document Server

    Schichtel, Peter

    Multi jet observables are a powerful tool to new physics as well as a boost to standard analysis strategies. We show their use in a reasonably model independent dark matter search and a jet veto Higgs analysis. We nd however that, these observables are plagued by huge theoretical uncertainties connected to unphysical scale parameters. In the democratic limit we compute analytically the all order resummed jet spectrum at leading log. It obeys so called staircase scaling. With the help of state of the art Monte Carlo tools we study the jet spectrum features in great detail. In addition we also study so called Poisson scaling. This allows us to develop a data driven strategy to x the standard model multi jet backgrounds.

  15. Jet physics at the LHC with ALICE

    International Nuclear Information System (INIS)

    Morsch, A.

    2005-01-01

    In central Pb-Pb collisions at the LHC, jet rates are expected to be high at energies at which ALICE can reconstruct jets over the background of the underlying event. This will open the possibility to quantify the effect of partonic energy loss through medium induced gluon radiation, jet quenching, by detailed measurement of the modification of the longitudinal and transverse structure of identified jets. In order to obtain probes sensitive to the properties of the QCD medium, it is mandatory to measure the high-p T parton fragments together with the low-p T particles from the radiated gluons. Hence, the excellent charged particle tracking capabilities of ALICE combined with the proposed electromagnetic calorimeter for ALICE, EMCAL, represent an ideal tool for jet quenching studies at the LHC. (orig.)

  16. Empirical model of the M 87 jet

    International Nuclear Information System (INIS)

    Shklovskij, I.S.

    1984-01-01

    The nature of the M87 jet is discussed. Recent observations of the M87 jet in radio, optical and X-ray regions, carried out with a sufficiently high resolving power, have revealed an identity of the brightness distribution at all frequencies. This points to a decisive role of the regular magnetic field variations along the jet for its overall structure. The bright knots of the jet are in the places where the field is enhanced. In the same places, a small fraction of relativistic electrons acquires large pitch-angles due to the interaction with plasma waves, leading to the synchrotron emission of the knots. The velocity of the plasma ejected from the nucleus of M87 should be 0.1 c. Thus, the M87 jet is one-sided

  17. Jet pumps hydrdynamics for application on BWRS

    International Nuclear Information System (INIS)

    Girardi, G.; Pitimada, D.

    1979-01-01

    An analysis of single-phase jet-pump hydrodynamics is carried out by this paper with special regard to the applications on cooling water recirculation in the boiling water reactors (BWR). Firstly, in order to asses on efficiency of jet pumps, several theories regarding the hydrodynamic of these machines are also investigated. The results of the above theories are critically analysed and compared regarding to water-jet-pump design, to operational performance curves and to section limits. Some general criteria in jet-pump design are introduced and values of geometric and kinematic parameters are suggested together with losses coefficients which are all concerned with the ''high ratio'' type jet pump of this typical application. Finally, the experimental test program following the sim of this research is briefly described

  18. Collimation of extragalactic jets: evidence from hotspots

    International Nuclear Information System (INIS)

    Banhatti, D.G.

    1984-01-01

    A linear relation with slope near unity is found between the logarithms of the hotspot size perpendicular to the source major axis and the distance from the core for 14 compact and/ or intense hotspots selected from a sample of 31 quasars having the largest angular sizes at various redshifts, as observed at 4.87 GHz with sub-arcsec resolution. A slope significantly less than 1 implies that the jet feeding the hotspot is laterally confined by the intergalactic medium, whereas a slope of 1 does not distinguish between a laterally confined jet and a free jet. The relation is found to have a slope near 1 implying a 0deg.1 jet confined within a cone of half-angle 15deg to 20deg or a 1deg-wide free jet. (author)

  19. Comparison of animated jet stream visualizations

    Science.gov (United States)

    Nocke, Thomas; Hoffmann, Peter

    2016-04-01

    The visualization of 3D atmospheric phenomena in space and time is still a challenging problem. In particular, multiple solutions of animated jet stream visualizations have been produced in recent years, which were designed to visually analyze and communicate the jet and related impacts on weather circulation patterns and extreme weather events. This PICO integrates popular and new jet animation solutions and inter-compares them. The applied techniques (e.g. stream lines or line integral convolution) and parametrizations (color mapping, line lengths) are discussed with respect to visualization quality criteria and their suitability for certain visualization tasks (e.g. jet patterns and jet anomaly analysis, communicating its relevance for climate change).

  20. The jet membrane-experiment: downstream sampling

    International Nuclear Information System (INIS)

    Campargue, R.

    1976-01-01

    The invasion separation effect of the free jet structure was found in 1966 at Saclay. In the Downstream Sampling Configuration patended by Campargue (1967), the light fraction is withdrawn from the supersonic central core, by skimming the separating free jet. From experimental and theoretical results obtained for gas and isotopic mixtures, the following points linked to operation and equipment costs, are considered: system description; influence of mass ratio, expansion ratio, nature of separating gas, ratio of upflow to separating jet flow, rarefaction. Fron an uninteresting aspect of Jet Membrane (elimination of background penetration), a new principle has been discovered to produce nozzle beams which may be of great interest for other separation processes involving free jets and/or molecular beams [fr