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Sample records for breakup reactions

  1. Status of breakup reaction theory

    International Nuclear Information System (INIS)

    Recent studies on breakup reactions with the continuum-discretized coupled-channels method are reviewed. The topics covered are: four-body breakup processes for 6He induced reaction, dynamical relativistic effects on Coulomb breakup, microscopic description of projectile breakup processes, description of ternary processes (new triple-α reaction rate) and new approach to inclusive breakup processes.

  2. Transfer to the continuum and Breakup reactions

    CERN Document Server

    Moro, A M

    2006-01-01

    A standard approach for the calculation of breakup reactions of exotic nuclei into two fragments is to consider inelastic excitations into the single particle continuum of the projectile. Alternatively one can also consider the transfer to the continuum of a system composed of the light fragment and the target. In this work we make a comparative study of the two approaches, underline the different inputs, and identify the advantages and disadvantages of each approach. Our test cases consist of the breakup of $^{11}$Be on a proton target at intermediate energies, and the breakup of $^8$B on $^{58}$Ni at energies around the Coulomb barrier.

  3. Breakup fusion theory of nuclear reactions

    International Nuclear Information System (INIS)

    Continuum spectra of particles emitted in incomplete fusion reactions are one of the major interests in current nuclear reaction studies. Based on an idea of the so-called breakup fusion (BF) reaction, several authors derived closed formulas for the singles cross section of the particles that are emitted. There have been presented, however, two conflicting cross section formulas for the same BF reaction. For convenience, we shall call one of them the IAV (Ichimura, Austern and Vincent) and the other UT (Udagawa and Tamura) cross section formulas. In this work, the formulation of the UT cross section formula (prior-form) is presented, and the post-form version of the IAV cross section formula is evaluted for a few α- and d-induced reactions based on the exact finite range method. It is shown that the values thus calculated are larger by an order of magnitude as compared with the experimental cross sections for the α-induced reactions, while they are comparable with the experimental cross sections for the d-induced reactions. A possible origin of why such a large cross section is resulted in the case of α-induced reactions is also discussed. Polarization of the residual compound nucleus produced in breakup fusion reactions are calculated and compared with experiments. It is shown that the polarization is rather sensitive to the deflection angles of the strongly absortive partial waves and to obtain a good fit with the experimental data a l-dependent potential in the incident channel is needed in order to stress the lower partial waves

  4. Coulomb and nuclear effects in breakup and reaction cross sections

    CERN Document Server

    Descouvemont, Pierre; Hussein, Mahir S

    2016-01-01

    We use a three-body Continuum Discretized Coupled Channel (CDCC) model to investigate Coulomb and nuclear effects in breakup and reaction cross sections. The breakup of the projectile is simulated by a finite number of square integrable wave functions. First we show that the scattering matrices can be split in a nuclear term, and in a Coulomb term. This decomposition is based on the Lippmann-Schwinger equation, and requires the scattering wave functions. We present two different methods to separate both effects. Then, we apply this separation to breakup and reaction cross sections of 7Li + 208Pb. For breakup, we investigate various aspects, such as the role of the alpha + t continuum, the angular-momentum distribution, and the balance between Coulomb and nuclear effects. We show that there is a large ambiguity in defining the 'Coulomb' and 'nuclear' breakup cross sections, since both techniques, although providing the same total breakup cross sections, strongly differ for the individual components. We suggest...

  5. Progress in all-order breakup reaction theories

    Indian Academy of Sciences (India)

    R Chatterjee

    2010-07-01

    Progress in breakup reaction theories, like the distorted wave Born approximation, the continuum discretized coupled channels method and the dynamical eikonal approximation, is brought into focus. The need to calculate exclusive reaction observables and the utility of benchmark tests as arbitrators of theoretical models are discussed.

  6. Break-up stage restoration in multifragmentation reactions

    Energy Technology Data Exchange (ETDEWEB)

    Raduta, Ad.R. [Institut de Physique Nucleaire, IN2P3-CNRS, F-91406 Orsay cedex (France)]|[NIPNE, Bucharest-Magurele, POB-MG 6 (Romania); Bonnet, E.; Borderie, B.; Le Neindre, N.; Rivet, M.F. [Institut de Physique Nucleaire, IN2P3-CNRS, F-91406 Orsay cedex (France); Piantelli, S. [Dip. di Fisica e Sezione INFN, Universita di Firenze, I-50019 Sesto Fiorentino, Fi (Italy)

    2007-02-15

    In the case of Xe+Sn at 32 MeV/nucleon multifragmentation reaction break-up fragments are built-up from the experimentally detected ones using evaluations of light particle evaporation multiplicities which thus settle fragment internal excitation. Freeze-out characteristics are extracted from experimental kinetic energy spectra under the assumption of full decoupling between fragment formation and energy dissipated in different degrees of freedom. Thermal kinetic energy is determined uniquely while for freeze-out volume - collective energy a multiple solution is obtained. Coherence between the solutions of the break-up restoration algorithm and the predictions of a multifragmentation model with identical definition of primary fragments is regarded as a way to select the true value. The broad kinetic energy spectrum of {sup 3}He is consistent with break-up genesis of this isotope. (authors)

  7. Significance Of Deuteron Breakup In A Halo Transfer Reaction

    CERN Document Server

    Yilmaz, M; Yilmaz, Mustafa; Gonul, Bulent

    2000-01-01

    We discuss the quasi-adiabatic approximations to the three-body wavefunction in breakup processes, clarifying the assumptions underlying the model. This suggests alternative approximation schemes. Using different theoretical three-body models, calculated differential cross section angular distributions for the Be-11(p,d) reaction,for which new preliminary data have been reported at 35 MeV, are presented. We show that calculations are sensitive to the inclusion of deuteron breakup and to the breakup model used, particularly if used to deduce absolute spectroscopic information on the 0{+} and 2{+} Be-10 core state parentages. There is also considerable sensitivity to the model used in calculations of the relative cross sections to the two states.

  8. Investigations of nuclear projectile break-up reactions

    International Nuclear Information System (INIS)

    The cross sections for radiative capture of α-particles, deuterons and protons by light nuclei at very low relative energies are of particular importance for the understanding of the nucleosynthesis of chemical elements and for determining the relative elemental abundances in stellar burning processes at various astrophysical sites. As example we quote the reactions α+d → 6Li+γ, α+3He → 7Be+γ, or α+12C → 16O+γ. As an alternative to the direct experimental study of these processes we consider the inverse process, the photodisintegration, by means of the virtual photons provided by a nuclear Coulomb field: Z+a → Z+b+c. The radiative capture process b+c → a+γ is related to the inverse process, the photodisintegration γ+a → b+c by the detailed balance theorem. Except for the extreme case very close to the threshold the phase space favours the photodisintegration cross section as compared to the radiative capture. The Coulomb dissociation cross section proves to be enhanced due to the large virtual photon number, seen by the passing projectile, and the kinematics of the process leads to particular advantages for studies of the interaction of the two break-up fragments at small relative energies Ebc. The conditions of dedicated experimental investigations are discussed and demonstrated by recent experimental and theoretical studies of the break-up of 156 MeV 6Li projectiles. In addition, a brief review about general features of break-up processes of light ions in the field of atomic nuclei is given. (orig.)

  9. No-capture breakup and incomplete fusion reactions induced by stable weakly bound nucleus 9Be

    Science.gov (United States)

    Seyyedi, S. A.

    2016-06-01

    The reactions including the stable weakly bound nucleus 9Be have been studied using the classical trajectory model accompanied with the experimental breakup function and the Aage-Winther interaction potential (AW95). In these calculations, the no-capture breakup and the incomplete fusion cross-sections as well as their competition at around the Coulomb barrier have been investigated. Our calculations showed that at a given far-Coulomb-barrier energy the incomplete fusion reaction in different distributions of angular momentum and energies can dominate the no-capture breakup reaction. This dominating process is reversed at the near-barrier energies.

  10. A dynamical theory of incomplete fusion reactions: The breakup-fusion reaction approach

    International Nuclear Information System (INIS)

    A dynamical theory of partial fusion reactions is presented, which may fill the gap between direct and compound nuclear reaction theories. With the new theory one can calculate partial fusion taking place in three-body (and many more) channels reached via direct reactions, e.g., breakup and knockout reactions. The authors present first the results for the cross section for such reactions, taking as an example breakup followed by fusion. They then discuss a physical picture which emerges from their theory, namely that the partial fusion reactions, particularly of the massive-transfer type, take place in a so-called deep peripheral region. It is also shown that the deep peripheral character of such processes diminishes as the mass of the fused system decreases, so that the reactions essentially evolve to the usual peripheral character. Finally, comparisons are made of results of numerical calculations with experimental data, taking as an example the /sup 159/Tb(/sup 14/N,α) reaction with E/sub lab/ = 95 MeV

  11. Reexamining closed-form formulae for inclusive breakup: Application to deuteron and $^6$Li induced reactions

    CERN Document Server

    Lei, Jin

    2015-01-01

    The problem of the calculation of inclusive breakup cross sections in nuclear reactions is reexamined. For that purpose, the post-form theory proposed by Ichimura, Austern and Vincent [Phys. Rev. C32, 431 (1985) is revisited, and an alternative derivation of the non-elastic breakup part of the inclusive breakup is presented, making use of the coupled-channels optical theorem. Using the DWBA version of this model, several applications to deuteron and $^6$Li reactions are presented and compared with available data. The validity of the zero-range approximation of the DWBA formula is also investigated by comparing zero-range with full finite-range calculations.

  12. Experimental and simulated d p breakup reaction data at 300, 400 and 500 MeV

    Directory of Open Access Journals (Sweden)

    Janek M.

    2014-01-01

    Full Text Available d p breakup reaction occupies large phase space. Two and three nucleon forces and relativistic effects can be investigated under various detector configuration. The results of simulation of d p breakup reaction in energy region from 300 to 500 MeV are presented. Preliminary results obtained at 300, 400 and 500 MeV of deuteron energy at some detector configurations at Nuclotron as well as future plans in investigation of relativistic effects are discussed.

  13. Approximations in fusion and breakup reactions induced by radioactive beams

    Energy Technology Data Exchange (ETDEWEB)

    Cardenas, W.H.Z.; Carlin Filho, N.; Hussein, M.S. [Sao Paulo Univ., SP (Brazil). Inst. de Fisica; Canto, L.F.; Donangelo, R. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Fisica; Lubian, J. [Universidade Federal Fluminense, Niteroi, RJ (Brazil). Inst. de Fisica; Centro de Aplicaciones Tecnologicas y Desarrollo Nuclear (CEADEN), Havana (Cuba); Romanelli, A. [Facultad de Ingenieria, Montevideo (Uruguay). Inst. de Fisica

    2000-07-01

    Some commonly used approximations for complete fusion and breakup transmission coefficients in collisions of weakly bound projectiles at near barrier energies are assessed. We show that they strongly depend on the adopted classical trajectory and can be significantly improved with proper treatment of the incident and emergent currents in the WKB approximation. (author)

  14. Classical simulations of heavy-ion fusion reactions and weakly-bound projectile breakup reactions

    Indian Academy of Sciences (India)

    S S Godre

    2014-05-01

    Heavy-ion collision simulations in various classical models are discussed. Heavy-ion reactions with spherical and deformed nuclei are simulated in a classical rigid-body dynamics (CRBD) model which takes into account the reorientation of the deformed projectile. It is found that the barrier parameters depend not only on the initial orientations of the deformed nucleus, but also on the collision energy and the moment of inertia of the deformed nucleus. Maximum reorientation effect occurs at near- and below-barrier energies for light deformed nuclei. Calculated fusion crosssections for 24Mg + 208Pb reaction are compared with a static-barrier-penetration model (SBPM) calculation to see the effect of reorientation. Heavy-ion reactions are also simulated in a 3-stage classical molecular dynamics (3S-CMD) model in which the rigid-body constraints are relaxed when the two nuclei are close to the barrier thus, taking into account all the rotational and vibrational degrees of freedom in the same calculation. This model is extended to simulate heavy-ion reactions such as 6Li + 209Bi involving the weakly-bound projectile considered as a weakly-bound cluster of deuteron and 4He nuclei, thus, simulating a 3-body system in 3S-CMD model. All the essential features of breakup reactions, such as complete fusion, incomplete fusion, no-capture breakup and scattering are demonstrated.

  15. Study of direct and sequential break-up reactions in 6Li+ 112Sn system

    International Nuclear Information System (INIS)

    The 6Li projectile while moving in the field of a target nucleus can not only dissociate into α+d but it can also first exchange a few nucleon with the target and then break up into two fragments. Identification of all these processes is important to understand the break-up mechanism of 6Li projectile and also to find the origin of the high yield of alpha particle production in such a reaction. In this paper, we present the exclusive measurement of breakup cross sections in 6Li+112Sn reaction exploring the above possibilities. Cross sections for both sequential as well as direct breakup are measured and compared with the theoretical calculations. The measured elastic scattering angular distributions were used as a constraint to the potential parameters that were used in the calculations to explain both elastic scattering and the breakup processes simultaneously

  16. Determining astrophysical three-body radiative capture reaction rates from inclusive Coulomb break-up measurements

    CERN Document Server

    Casal, J; Arias, J M; Gómez-Camacho, J

    2016-01-01

    A relationship between the Coulomb inclusive break-up probability and the radiative capture reaction rate for weakly-bound three-body systems is established. This direct link provides a robust procedure to estimate the reaction rate for nuclei of astrophysical interest by measuring inclusive break-up processes at different energies and angles. This might be an advantageous alternative to the determination of reaction rates from the measurement of $B(E1)$ distributions through exclusive Coulomb break-up experiments. In addition, it provides a reference to assess the validity of different theoretical approaches that have been used to calculate reaction rates. The procedure is applied to $^{11}$Li ($^{9}$Li+n+n) and $^6$He ($^{4}$He+n+n) three-body systems for which some data exist.

  17. Determining astrophysical three-body radiative capture reaction rates from inclusive Coulomb break-up measurements

    Science.gov (United States)

    Casal, J.; Rodríguez-Gallardo, M.; Arias, J. M.; Gómez-Camacho, J.

    2016-04-01

    A relationship between the Coulomb inclusive break-up probability and the radiative capture reaction rate for weakly bound three-body systems is established. This direct link provides a robust procedure to estimate the reaction rate for nuclei of astrophysical interest by measuring inclusive break-up processes at different energies and angles. This might be an advantageous alternative to the determination of reaction rates from the measurement of B (E 1 ) distributions through exclusive Coulomb break-up experiments. In addition, it provides a reference to assess the validity of different theoretical approaches that have been used to calculate reaction rates. The procedure is applied to 11Li (9Li+n +n ) and 6He (4He+n +n ) three-body systems for which some data exist.

  18. Numerical assessment of post-prior equivalence for inclusive breakup reactions

    CERN Document Server

    Lei, Jin

    2015-01-01

    We address the problem of the post-prior equivalence in inclusive breakup reactions induced by weakly-bound nuclei. The problem is studied within the DWBA model of Ichimura, Austern, Vincent [Phys. Rev. C32, 431 (1985)]. The post and prior formulas obtained in this model are briefly recalled, and applied to several breakup reactions induced by deuterons and $^6$Li projectiles, to test their actual numerical equivalence. The different contributions of the prior-form formula are also discussed. A critical comparison with the prior-form distorted-wave Born approximation (DWBA) model of Udagawa and Tamura [Phys. Rev. C24, 1348 (1981)] is also provided.

  19. Description of Four-Body Breakup Reaction with the Method of Continuum-Discretized Coupled-Channels

    CERN Document Server

    Egami, Tomoaki; Ogata, Kazuyuki; Yahiro, Masanobu

    2008-01-01

    We present a method for smoothing discrete breakup $S$-matrix elements calculated by the method of continuum-discretized coupled-channels (CDCC). This smoothing method makes it possible to apply CDCC to four-body breakup reactions. The reliability of the smoothing method is confirmed for two cases, $^{58}$Ni($d$, $p n$) at 80 MeV and the $E1$ transition of $^6$He. We apply CDCC with the smoothing method to $^6$He breakup reaction at 22.5 MeV. Multi-step breakup processes are found to be important.

  20. Near-Far Description of Elastic and Breakup Reactions of Halo Nuclei

    CERN Document Server

    Hussein, M S; Baye, D

    2012-01-01

    The angular distributions for elastic scattering and breakup of halo nuclei are analysed using a near-side/far-side decomposition within the framework of the dynamical eikonal approximation. This analysis is performed for 11Be impinging on Pb at 69AMeV. These distributions exhibit very similar features. In particular they are both near-side dominated, as expected from Coulomb-dominated reactions. The general shape of these distributions is sensitive mostly to the projectile-target interactions, but is also affected by the extension of the halo. This suggests that the link between elastic scattering and a possible loss of flux towards the breakup channel is not obvious.

  1. Reaction mechanism for the symmetric breakup of 24Mg following an interaction with 12C

    International Nuclear Information System (INIS)

    Data on the yield of the symmetric breakup of 24Mg as a function of beam energy are presented and compared with detailed calculations of the energy dependence. The 24Mg states seen in symmetric breakup agree with previously observed breakup states having spin and parities Jπ=4+,(6+),8+. The data allow the variations of yield for indivual states to be judged, as the beam energy is varied. The variation in the yield of the 4+ states is compared in detail with calculations assuming several possible compound nuclear or direct reaction mechanisms. It is concluded that a massive (12C) transfer or a simple statistical compound process are unlikely mechanisms, but that each of several other mechanisms is consistent with the data. ((orig.))

  2. Vector and tensor analysing powers in deuteron-proton breakup reactions at intermediate energies

    CERN Document Server

    Chiladze, D; Dymov, S; Glagolev, V; Hartmann, M; Hejny, V; Kacharava, A K; Keshelashvili, I; Khoukaz, A; Koch, H R; Komarov, V; Kulessa, P; Kulikov, A; Macharashvili, G; Maeda, Y; Mersmann, T; Merzliakov, S; Mikirtytchiants, S; Mussgiller, A; Nioradze, M; Ohm, H; Rathmann, F; Schleichert, R; Stein, H J; Ströher, H; Uzikov, Y; Wilkin, C; Yaschenko, S; Uzikov, Yu.

    2006-01-01

    Vector and tensor analysing powers of the d(pol)p->(pp)n (charge-exchange) and d(pol)p->(pn)p (non-charge-exchange) breakup reactions have been measured with the ANKE spectrometer at the COSY ring at a deuteron beam energy of 1170 MeV for small momentum transfers to the low excitation energy (pp) or (pn) systems. A quantitative understanding of the values of A_xx and A_yy for the charge-exchange reaction is provided by impulse approximation calculations. The data suggest that spin-flip isospin-flip transitions, which dominate the charge-exchange breakup of the deuteron, are also important in the non-charge-exchange reaction.

  3. Determination of 8B(p,gamma)9C reaction rate from 9C breakup

    CERN Document Server

    Fukui, Tokuro; Minomo, Kosho; Yahiro, Masanobu

    2012-01-01

    The astrophysical factor of the 8B(p,gamma)9C at zero energy, S18(0), is determined from three-body model analysis of 9C breakup processes. The elastic breakup 208Pb(9C,p8B)208Pb at 65 MeV/nucleon and the one-proton removal reaction of 9C at 285 MeV/nucleon on C and Al targets are calculated with the continuum-discretized coupled-channels method (CDCC) and the eikonal reaction theory (ERT), respectively. The asymptotic normalization coefficient (ANC) of 9C in the p-8B configuration extracted from the two reactions show good consistency, in contrast to in the previous studies. As a result of the present analysis, S18(0) = 66 \\pm 10 eVb is obtained.

  4. Interplay of projectile breakup and target excitation in reactions induced by weakly-bound nuclei

    CERN Document Server

    Gomez-Ramos, M

    2016-01-01

    In this work, we reexamine the extension of the CDCC formalism to include target excitation and apply it to a variety of reactions to study the effect of breakup on inelastic cross sections. We use a transformed oscillator basis to discretize the continuum of the projectiles in the different reactions and use the extended CDCC method developed in this work to solve the resulting coupled differential equations. A new code has been developed to perform the calculations. Reactions 58Ni(d, d) 58Ni*, 24Mg(d, d) 24Mg* , 144Sm( 6Li, 6Li) 144Sm* and 9Be( 6Li, 6Li) 9Be* are studied. Satisfactory agreement is found between experimental data and extended CDCC calculations. The studied CDCC method is proved to be an accurate tool to describe target excitation in reactions with weakly-bound nuclei. Moderate effects of breakup on inelastic observables are found for the reactions studied. Cross section magnitudes are not modified much, but angular distributions present smoothing when opposed to calculations without breakup.

  5. Exclusive measurements of nuclear breakup reactions of 17Ne

    Directory of Open Access Journals (Sweden)

    Wamers F.

    2014-03-01

    Full Text Available We have studied one-proton-removal reactions of about 500MeV/u 17Ne beams on a carbon target at the R3B/LAND setup at GSI by detecting beam-like 15O-p and determining their relative-energy distribution. We exclusively selected the removal of a 17Ne halo proton, and the Glauber-model analysis of the 16F momentum distribution resulted in an s2 contribution in the 17Ne ground state of about 40%.

  6. Coulomb dissociation and momentum distributions for 11Li → 9Li + n + n breakup reactions

    International Nuclear Information System (INIS)

    Momentum distributions for the 11Li → 9Li+n+n breakup reaction, generated by Coulomb dipole excitations, axe calculated in a 3-body model for 11Li. The relative momentum distribution of the two neutrons is in good agreement with recent 3-body coincidence measurements but the momentum distribution for the 9Li recoil and the decay energy spectrum are much narrower than observed. These discrepancies may be due to higher order dynamical effects which have been ignored

  7. Role of projectile breakup in {sup 6}He and {sup 6}Li induced fusion reactions around barrier energies

    Energy Technology Data Exchange (ETDEWEB)

    Kumari, Anju; Kharab, Rajesh, E-mail: kharabrajesh@rediffmail.com

    2015-09-15

    The influence of projectile breakup on fusion cross section for {sup 6}He + {sup 209}Bi, {sup 6}He + {sup 64}Zn, {sup 6}Li + {sup 209}Bi and {sup 6}Li + {sup 64}Zn reactions at near barrier energies is studied within the framework of quantum diffusion approach. The breakup does not affect the fusion induced by {sup 6}He, whereas a significant suppression for {sup 6}Li induced reaction is observed in below barrier energy region.

  8. Breakup and finite-range effects on the 8B(d,n)9C reaction

    CERN Document Server

    Fukui, Tokuro; Yahiro, Masanobu

    2014-01-01

    The astrophysical factor of 8B(p,{\\gamma})9C at zero energy, S18(0), is determined by a three-body coupled-channels analysis of the transfer reaction 8B(d,n)9C at 14.4 MeV/nucleon. Effects of the breakup channels of deuteron are investigated with the continuum-discretized coupled-channels method (CDCC). It is found that the transfer process through the deuteron breakup states, its interference with that through the deuteron ground state in particular, gives a large increase in the transfer cross section. The finite-range effects with respect to the proton- neutron relative coordinate are found to be less than 5%. As a result of the present analysis, S18(0) = 33 +/- 10 eVb is obtained that is smaller than the result of the previous DWBA analysis by about 26%.

  9. Analysis of Coulomb breakup reactions of 19C on heavy targets

    International Nuclear Information System (INIS)

    The Coulomb breakup reactions 181Ta(19C, 18C+n)181Ta and 208Pb(19C, 18C+n)208Pb has been investigated at 88 A MeV and 67 A MeV beam energies respectively within the theoretical framework of eikonal approximation with a motive to estimate the relative contribution of higher order multipole transitions, especially of electric quadrupole and dipole-quadrupole interference terms. The results so obtained reflect the finite contribution of electric quadrupole terms at higher relative energies while the dipole-quadrupole interference terms show their presence through longitudinal momentum distribution of core. (author)

  10. Importance of lifetime effects in breakup and suppression of complete fusion in reactions of weakly bound nuclei

    Science.gov (United States)

    Cook, K. J.; Simpson, E. C.; Luong, D. H.; Kalkal, Sunil; Dasgupta, M.; Hinde, D. J.

    2016-06-01

    Background: Complete fusion cross sections in collisions of light weakly bound nuclei and high-Z targets show suppression of complete fusion at above-barrier energies. This has been interpreted as resulting from the breakup of the weakly bound nucleus prior to reaching the fusion barrier, reducing the probability of complete charge capture. Below-barrier studies of reactions of 9Be have found that the breakup of 8Be formed by neutron stripping dominates over direct breakup and that transfer-triggered breakup may account for the observed suppression of complete fusion. Purpose: This paper investigates how the above conclusions are affected by lifetimes of the resonant states that are populated prior to breakup. If the mean life of a populated resonance (above the breakup threshold) is much longer than the fusion time scale, then its breakup (decay) cannot suppress complete fusion. For short-lived resonances, the situation is more complex. This work explicitly includes the mean life of the short-lived 2+ resonance in 8Be in classical dynamical model calculations to determine its effect on energy and angular correlations of the breakup fragments and on model predictions of suppression of cross sections for complete fusion at above-barrier energies. Method: Previously performed coincidence measurements of breakup fragments produced in reactions of 9Be with 144Sm, 168Er, 186W, 196Pt, 208Pb, and 209Bi at energies below the barrier have been reanalyzed using an improved efficiency determination of the BALiN detector array. Predictions of breakup observables and of complete and incomplete fusion at energies above the fusion barrier are then made using the classical dynamical simulation code platypus, modified to include the effect of lifetimes of resonant states. Results: The agreement of the breakup observables is much improved when lifetime effects are included explicitly. Sensitivity to subzeptosecond lifetime is observed. The predicted suppression of complete fusion

  11. Measurement of the Breakup Cross Sections in 6He+9Be Reaction at 25 MeV/Nucleon

    Institute of Scientific and Technical Information of China (English)

    WANG Jia; HU Qing-Yuan; WU Cui-E; A. Ozawa; Y. Yamaguchi; R. Kanungo; D. Fang; I. Tanihata; YE Yan-Lin; JIANG Dong-Xing; ZHANG Gao-Long; PANG Dan-Yang; LI Zhi-Huan; ZHENG Tao; LI Xiang-Qing; WANG Quan-Jin

    2005-01-01

    @@ The breakup reaction cross sections were measured for the reaction of 6He at 25 MeV/nucleon from 9Be target with intensity of 105 pps. By fitting the energy spectra of breakup α particles with Gaussian functions, the angular distribution of differential cross sections in the laboratory system has been extracted and compared with the Serber model calculations. The good agreement between the calculation and the experimental data favours a dominant configuration of the 4He core plus valence neutrons for the structure of 6He.

  12. Experimental study of relativistic effects in the dp breakup reaction using the WASA detector

    Directory of Open Access Journals (Sweden)

    Kłos B.

    2014-03-01

    Full Text Available An experiment to investigate the 1H(d→$\\overrightarrow d $, ppn breakup reaction at 340 MeV, 360 MeV and 400 MeV deuteron beam energy has been performed at the Cooler Synchrotron COSY-Jülich with the WASA detector. The main goal was to study of various aspects of few-nucleon dynamics in the medium energy region, with a particular emphasis on relativistic effects and their interplay with three nucelon forces. The almost 4π geometry of the WASA detector gives an unique possibility to study the different aspects of nucleon-nucleon dynamics in the three nucleon system. The preliminary analysis of the collected data is presented.

  13. Study of the He3 breakup reaction and the triton production spectra at 283 MeV

    International Nuclear Information System (INIS)

    The breakup of He3 ions at 94MeV/nucleon was studied in inclusive experiments on nuclei ranging from C12 to Pb208, and in coincidence experiments (γd) and (γt) on an A127 target. The inclusive spectra of protons and deuterons show an important contribution of the He3 breakup reaction to the reaction cross section (80%). Analysis of the dependence as a function of A confirms a peripheral mechanism. The coincidence experiment gives a proportion of inelastic breakup in the inclusive cross section of 40 %. Examination of triton spectra reveals that at 94 MeV the dominant reaction is not breakup transfer as at lower energies, but charge exchange. The spectra peak at energies of 20MeV, compatible with the excitation of a mixture of L=1 and L=2 states. The variation of the cross section following an A1/3 law indicates a peripheral mechanism for the (He3,t) reaction too. The (γ-t) coincidence reaction showing residual nucleus production near the target nucleus reinforces this result

  14. Importance of lifetime effects in breakup and suppression of complete fusion in reactions of weakly bound nuclei

    CERN Document Server

    Cook, K J; Luong, D H; Kalkal, Sunil; Dasgupta, M; Hinde, D J

    2016-01-01

    Complete fusion cross sections in collisions of light, weakly bound nuclei and high Z targets show above-barrier suppression of complete fusion. This has been interpreted as resulting from breakup of the weakly bound nucleus prior to reaching the fusion barrier, reducing the probability of complete fusion. This paper investigates how these conclusions are affected by lifetimes of the resonant states that are populated prior to breakup. If the mean life of a populated resonance is much longer than the fusion timescale, then its breakup cannot suppress complete fusion. For short-lived resonances, the situation is more complex. This work includes the mean life of the short-lived 2+ resonance in 8Be in classical dynamical model calculations to determine its effect on energy and angular correlations of the breakup fragments and on predictions of fusion suppression. Coincidence measurements of breakup fragments produced in reactions of 9Be with 144Sm, 168Er, 186W, 196Pt, 208Pb and 209Bi at energies below the barrie...

  15. Study of {sup 19}C by breakup reactions; Etude du {sup 19}C par reactions de cassure

    Energy Technology Data Exchange (ETDEWEB)

    Liegard, Emmanuel [Lab. de Physique Corpusculaire, Caen Univ., 14 Caen (France)

    1998-01-07

    To date studies of halo nuclei have been principally focussed on the A 11 systems {sup 11}Li and {sup 11}Be. The evolution of the properties of the halo with the mass of the system and the binding energy and angular momentum of the halo nucleons is a question of fundamental importance. It was in this spirit that the present study of {sup 19}C (S{sub n} = 240 {+-} 100 keV) was undertaken. The experiment was performed at GANIL using a secondary {sup 19}C beam ({approx_equal} 15 pps at 36 MeV/nucleon) produced via fragmentation. The experimental setup which included the neutron array DEMON, provided for identification of the core-breakup and dissociation reaction channels. In the first case, a very narrow single neutron angular distribution (FWHM = 64 {+-} 17 MeV/c) was observed for {sup 19}C, in contrast to that found for three `reference` nuclei {sup 21}N, {sup 22}O and {sup 24}F (FWHM {approx_equal} 165 MeV/c). This result could be interpreted within the framework of the core-breakup reaction model of a one-neutron halo nucleus. The results obtained for dissociation, while supporting the existence of the halo, indicated that it is not well developed. In addition, a comparison between the present results, the parallel momentum distributions for the core ({sup 18}C) and theoretical predictions have allowed conclusions to be drawn regarding the configuration of the valence neutron. In particular, a purely 2s{sub 1/2} of 1d{sub 5/2} configuration is excluded and mixing, possible with core excited states, must be considered. A probable ground state spin-parity assignment of 3{sup +}/2 or 5{sup +}/2 is suggested. (author) 150 refs., 278 figs., 28 tabs.

  16. A distorted-wave Born-approximation theory of heavy-ion induced projectile break-up reactions

    International Nuclear Information System (INIS)

    A distorted-wave Born-approximation (DWBA) formalism is developed to describe the 'elastic' and 'inelastic' break-up of the projectile in the heavy ion induced reactions. Using a 'local momentum approximation' and the surface localization property of these reactions expressions for the DWBA transition amplitude are derived. One of the attractive features of the present formulation is the fact that the readial integrals involved in it are the same as those contained in the transition amplitude evaluated with a zero range approximation. The validity of the approximations used in our derivations has been tested and it is shown that these approximations are well fulfilled. (orig.)

  17. Measurement of the reaction 2H(e,e') at 180 degrees close to the deuteron breakup threshold.

    Science.gov (United States)

    Ryezayeva, N; Arenhövel, H; Burda, O; Byelikov, A; Chernykh, M; Enders, J; Griesshammer, H W; Kalmykov, Y; von Neumann-Cosel, P; Ozel, B; Poltoratska, I; Pysmenetska, I; Rangacharyulu, C; Rathi, S; Richter, A; Schrieder, G; Shevchenko, A; Yevetska, O

    2008-05-01

    Inclusive inelastic electron scattering off the deuteron under 180 degrees has been studied at the S-DALINAC close to the breakup threshold at momentum transfers q=0.27 fm;{-1} and 0.74 fm;{-1} with good energy resolution sufficient to map in detail the spin flip M1 response, which governs the starting reaction pn-->dgamma of big-bang nucleosynthesis over most of the relevant temperature region. Results from potential model calculations and (for q=0.27 fm;{-1}) from pionless nuclear effective field theory are in excellent agreement with the data.

  18. Equivalence of post and prior sum rules for inclusive breakup reactions

    International Nuclear Information System (INIS)

    A critical examination of sum rules derived previously by Austern and Vincent (post form) and by Udagawa and Tamura (prior form) demonstrates that agreement between the two approaches is obtained if certain approximations implicit in the Udagawa-Tamura prior-form derivation are avoided. We examine the relation of the two approaches to singularities of the post-form distorted wave Born approximation matrix element and to the procedures for reduction of a many-body theory by use of effective operators in a model space. The two-step heuristic model is seen to be invalid for prior-form inelastic breakup; it is necessary to take account of nuclear excitations during projectile breakup. Careful treatment of the non-Hermiticity of kinetic energy operators with respect to continuum wave functions is required

  19. Continuum-discretized coupled-channels method for four-body breakup reactions

    CERN Document Server

    Kamimura, M; Hiyama, E; Ogata, K; Iseri, Y; Yahiro, M

    2005-01-01

    Development of the method of CDCC (Continuum-Discretized Coupled-Channels) from the level of three-body CDCC to that of four-body CDCC is reviewed. Introduction of the pseudo-state method based on the Gaussian expansion method for discretizing the continuum states of two-body and three-body projectiles plays an essential role in the development. Furthermore, introduction of the complex-range Gaussian basis functions is important to improve the CDCC for nuclear breakup so as to accomplish that for Coulomb and nuclear breakup. A successful application of the four-body CDCC to $^6$He+$^{12}$C scattering at 18 and 229.8 MeV is reported.

  20. Charge correlations in the breakup of gold projectiles in reactions at E/A=600 MeV

    International Nuclear Information System (INIS)

    In the present thesis the charge correlations in the breakup of gold projectiles in heavy ion collisions at an incident energy of E/A=600 MeV were studied. Thereby it has been proved that the sum of the charges from the projectile source under exclusion of the protons (Zbound) is saliently suited for the classification of the nuclear reactions. At large values of Zbound we fins fission and spallation reactions. For smaller values of Zbound we observe events with an increasing number of medium-heavy fragments. Thereby the multifragment events appear in the Dalitz diagrams as a continuation of more symmetric becoming spallation events. In reactions with Zbound ≅ 35 the conditions for the formation of medium-heavy fragments are optimal and the multifragment events represent the dominating exit channel. A mean multiplicity of the medium-heavy fragments of ≅ 4 is reached. (orig./HSI)

  1. Investigation of the role of break-up processes on the fusion of 16O induced reactions

    International Nuclear Information System (INIS)

    An experiment was carried out to explore heavy ion incomplete fusion reaction dynamics, within the framework of the break-up fusion model, at energies near and above the Coulomb barrier. Excitation functions for several radionuclides produced via xn, pxn, and αxn channels were measured in the 16O+181Ta system at energies of ≅76-100 MeV. The experimental excitation functions were compared with those calculated using the theoretical model code PACE4. It was observed that excitation functions of xn/pxn channels are in good agreement with theoretical predictions. However, a significant enhancement in the measured excitation functions of α-emitting channels was observed and attributed to the incomplete fusion processes. The incomplete fusion fraction (FICF) that gives the relative importance of complete and incomplete fusion processes was found to increase with energy. The results are discussed in terms of α-cluster structure of the projectile on various fusion reactions.

  2. The influence of experimental setup on the spectroscopy investigation of $^{\\mathrm{14}}$Be by Coulomb breakup reaction

    CERN Document Server

    Song, Yu-Shou; Hu, Li-Yuan; Liu, Hui-Lan; Wu, Hong-Yi

    2015-01-01

    The two-body core+$2n$ cluster structure was implemented to describe the two-neutron halo nucleus $^{\\mathrm{14}}\\mathrm{Be}$, where the core$^{\\mathrm{12}}\\mathrm{Be}$ was assumed inert and at ground state and the dineutron was assumed at pure $2S_0$ state. Based on such a structure the three-body continuum-discretized coupled-channel (CDCC) calculation was successfully used to deal with the $^{\\mathrm{14}}\\mathrm{Be}$ breakup reactions of $^{\\mathrm{14}}\\mathrm{Be}+^{\\mathrm{12}}\\mathrm{C}$ at 68~MeV/nucleon and $^{\\mathrm{14}}\\mathrm{Be}+ $Pb at 35~MeV/nucleon.Consequently, we modeled the kinematically complete measurement experiment of $^{\\mathrm{14}}\\mathrm{Be}$ (35~MeV/nucleon) Coulomb breakup at a lead target with the help of Geant4. From the simulation data the relative energy spectrum was constructed by the invariant mass method and $B(E1)$ spectrum was extracted using virtual photon model. The influence of the target thickness and detector performance on the spectroscopy was investigated.

  3. A study of proton breakup from exotic nuclei through various reaction mechanisms in 40 A - 80 AMeV energy range

    International Nuclear Information System (INIS)

    We have studied the single proton breakup from weakly bound exotic nuclei due to several reaction mechanisms separately and their total and the interference effects, in order to clarify quantitatively which mechanism would dominate the measured observables. We have considered: first, the recoil effect of the core-target Coulomb potential which we distinguish from the direct proton-target Coulomb potential, and secondly the nuclear breakup, which consists of stripping and diffraction. Thus, we have calculated the absolute values of breakup cross sections and parallel momentum distributions (LMD) for 8B and 17F projectiles on a light and a heavy target in a range of intermediate incident energies (40 A-80 A MeV) for each reaction mechanism. Furthermore the interference among the two Coulomb effects and nuclear diffraction has been studied in detail. The calculation of the direct and recoil Coulomb effects separately and of their interference is the new and most relevant aspect of this work. (authors)

  4. Analysis of LMD data of core coming from Ta(15C, 14C+n)Ta Coulomb breakup reaction

    International Nuclear Information System (INIS)

    It is well established fact that the neutron-halo nucleus is a loosely bound exotic nuclear state where in the valence neutron is found mostly at a much larger distance from the remaining core. The development of radioactive ion beams (RI) has provided a great opportunity to explore various peculiar properties of such nuclear systems. Consequently lots of efforts have been made on theoretical and experimental fronts to understand the exotic features of halo nuclei. One of the clear manifestations of exotic properties of isotopes lying near neutron drip line is the loss of magicity and the tendency to posses prolate deformation. In this conference contribution, we study Ta(15C, 14C+n)Ta Coulomb breakup reaction with a special emphasis on the study of effects of deformation and to investigate the possibility of occupying d-orbital by valence neutron in 15 C

  5. An investigation of the role of spectroscopic factors in the breakup reaction of 11Be

    CERN Document Server

    Canbula, Bora; Canbula, Deniz; Babacan, Halil

    2014-01-01

    The experimental elastic cross section data of the projectile 11Be on target 12C at 49.3 MeV/nucleon energy is analysed. The calculations for the elastic scattering is performed by the phenomenological optical model. The different optical potentials to include breakup effects into the calculations, which are neutron+12C, neutron+10Be and 10Be+12C are described with the aid of the global potentials for neutron interactions and fitted to experimental data for the core and target interaction. Also, the first analysis of the optical model for 10Be on target 12C at 39.1 MeV is done for building the interaction potential of the core and the target for 11Be. For investigating the effects of the spectroscopic factor obtained from the direct capture process using the nuclear level density are compared with the previous cross section and spectroscopic factor results. Obtained results for the elastic cross section are reproduced the experimental data very well, and shows the requirement of including spectroscopic proper...

  6. Effects of projectile resonances on the total, Coulomb, and nuclear breakup cross sections in the 6Li+152Sm reaction

    Science.gov (United States)

    Mukeru, B.; Lekala, M. L.

    2016-08-01

    In this paper we analyze the effects of the projectile resonances on the total, Coulomb, and nuclear breakup cross sections as well as on the Coulomb-nuclear interferences at different arbitrary incident energies. It is found that these resonances have non-negligible effects on the total, Coulomb, and nuclear breakup cross sections. Qualitatively, they have no effects on the constructiveness or destructiveness of the Coulomb-nuclear interferences. Quantitatively, we obtained that these resonances increase by 7.38%, 7.58%, and 20.30% the integrated total, Coulomb, and nuclear breakup cross sections, respectively at Elab=35 MeV . This shows that the nuclear breakup cross sections are more affected by the effects of the projectile resonances than their total and Coulomb breakup counterparts. We also obtain that the effects of the resonances on the total, Coulomb, and nuclear breakup cross sections decrease as the incident energy increases.

  7. Probing elastic and inelastic breakup contributions to intermediate-energy two-proton removal reactions

    CERN Document Server

    Wimmer, K; Gade, A; Tostevin, J A; Baugher, T; Chajecki, Z; Coupland, D; Famiano, M A; Ghosh, T K; Grinyer, G F; Hodges, R; Howard, M E; Kilburn, M; Lynch, W G; Manning, B; Meierbachtol, K; Quarterman, P; Ratkiewicz, A; Sanetullaev, A; Stroberg, S R; Tsang, M B; Weisshaar, D; Winkelbauer, J; Youngs, R Winkler M

    2012-01-01

    The two-proton removal reaction from 28Mg projectiles has been studied at 93 MeV/u at the NSCL. First coincidence measurements of the heavy 26Ne projectile residues, the removed protons and other light charged particles enabled the relative cross sections from each of the three possible elastic and inelastic proton removal mechanisms to be determined. These more final-state-exclusive measurements are key for further interrogation of these reaction mechanisms and use of the reaction channel for quantitative spectroscopy of very neutron-rich nuclei. The relative and absolute yields of the three contributing mechanisms are compared to reaction model expectations - based on the use of eikonal dynamics and sd-shell-model structure amplitudes.

  8. Estimation of the breakup cross sections in $^6$He+$^{12}$C reaction within high-energy approximation and microscopic optical potential

    CERN Document Server

    Zemlyanaya, E V; Lukyanov, K V

    2010-01-01

    The breakup cross sections in the reaction $^6$He+$^{12}$C are calculated at about 40 MeV/nucleon using the high-energy approximation (HEA) and with the help of microscopic optical potentials (OP) of interaction with the target nucleus $^{12}$C of the projectile nucleus fragments $^4$He and 2n. Considering the di-neutron $h$=2n as a single particle the relative motion $h\\alpha$ wave function is estimated so that to explain both the separation energy of $h$ in $^6$He and the rms radius of the latter. The stripping and absorbtion total cross sections are calculated and their sum is compared with the total reaction cross section obtained within a double-folding microscopic OP for the $^6$He+$^{12}$C scattering. It is concluded that the breakup cross sections contribute in about 50% of the total reaction cross section.

  9. Analysis on two-neutron correlation through Dalitz plot of Coulomb breakup reaction for 6He

    International Nuclear Information System (INIS)

    A new method to describe the three-body decaying states is developed. In this method, the Lippmann–Schwinger equation is combined with the complex scaling method to take the correct boundary condition into account. For the application, the E1 transition strength of 6He is investigated. The energy and Dalitz distributions of the E1 transition are calculated, and the internal correlation of 6He is discussed. As results, it is found that the 6He → 5He(3/2-)+n → 4He+n+n sequential decay process is dominant in the E1 transition reaction of 6He. (author)

  10. The Breakup

    Science.gov (United States)

    Lum, Lydia

    2011-01-01

    This article reports on the breakup between Texas Southmost College (TSC) and the upper-division University of Texas at Brownsville (UTB). The split marks the official end of an unusual 20-year partnership between TSC and the University of Texas System that, for the first time, ushered four-year university education into overwhelmingly Latino…

  11. Influence of neutron correlations on nuclear break-up reaction both from theoretical and experimental point of view

    International Nuclear Information System (INIS)

    Nuclear break-up has been studied both from an experimental and a theoretical point of view and has shown to be a powerful tool to probe nucleon correlations in nuclei. A theory beyond mean-field, called TDDM, (Time Dependant Density Matrix) taking into account two-body correlations has been developed. The dynamical evolution of a correlated nuclei can be described and especially nuclear break-up. This study shows that the distributions of relative angle between the two neutrons strongly differ when varying initial correlations: two nucleons close together in the nuclei will lead to small relative angle after emission whereas two nucleons far from each other gives large relative angles. From an experimental point of view, correlations between the two neutrons in the halo of the Borromean nucleus He6 have been investigated. Its ground state is predicted to have two dominant configurations: the di-neutron configuration where the two neutrons are very close to each other and the cigar configuration, where the two neutrons are on opposite side with respect to the core. Nuclear break-up of He6 on a lead target has been studied at GANIL with a SPIRAL beam. The alpha particles coming out of the break-up where detected by a stripped Silicon detector coupled to a Silicon-Lithium detector and the neutrons by EDEN and the Neutron Wall, in order to get a large angular coverage. Angular correlation functions extracted from data show both strong correlation at small relative angles and at large relative angle corresponding respectively to the contribution of the di-neutron configuration and of the cigar like configuration. So He6 ground state seems to be a superposition of these two configurations. (author)

  12. Satellite Breakup Risk Mitigation

    Science.gov (United States)

    Leleux, Darrin P.; Smith, Jason T.

    2006-01-01

    Many satellite breakups occur as a result of an explosion of stored energy on-board spacecraft or rocket-bodies. These breakups generate a cloud of tens or possibly hundreds of thousands of debris fragments which may pose a transient elevated threat to spaceflight crews and vehicles. Satellite breakups pose a unique threat because the majority of the debris fragments are too small to be tracked from the ground. The United States Human Spaceflight Program is currently implementing a risk mitigation strategy that includes modeling breakup events, establishing action thresholds, and prescribing corresponding mitigation actions in response to satellite breakups.

  13. Measurement of the 12C(e,e′p)11B two-body breakup reaction at high missing momentum

    International Nuclear Information System (INIS)

    The five-fold differential cross section for the 12C(e,e′p)11B reaction was determined over a missing momentum range of 200–400 MeV c−1, in a kinematics regime with xB>1 and Q2=2.0 (GeV c−1)2. A comparison of the results with previous lower missing momentum data and with theoretical models are presented. The extracted distorted momentum distribution is shown to be consistent with previous data and extends the range of available data up to 400 MeV c−1. The theoretical calculations are from two very different approaches, one mean field and the other short range correlated; yet for this system the two approaches show striking agreement with the data and each other up to a missing momentum value of 325 MeV c−1. For larger momenta, the calculations diverge which is likely due to the factorization approximation used in the short range approach. (paper)

  14. Fermi breakup and the statistical multifragmentation model

    Energy Technology Data Exchange (ETDEWEB)

    Carlson, B.V., E-mail: brett@ita.br [Departamento de Fisica, Instituto Tecnologico de Aeronautica - CTA, 12228-900 Sao Jose dos Campos (Brazil); Donangelo, R. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Cidade Universitaria, CP 68528, 21941-972, Rio de Janeiro (Brazil); Instituto de Fisica, Facultad de Ingenieria, Universidad de la Republica, Julio Herrera y Reissig 565, 11.300 Montevideo (Uruguay); Souza, S.R. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Cidade Universitaria, CP 68528, 21941-972, Rio de Janeiro (Brazil); Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, CP 15051, 91501-970, Porto Alegre (Brazil); Lynch, W.G.; Steiner, A.W.; Tsang, M.B. [Joint Institute for Nuclear Astrophysics, National Superconducting Cyclotron Laboratory and the Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)

    2012-02-15

    We demonstrate the equivalence of a generalized Fermi breakup model, in which densities of excited states are taken into account, to the microcanonical statistical multifragmentation model used to describe the disintegration of highly excited fragments of nuclear reactions. We argue that such a model better fulfills the hypothesis of statistical equilibrium than the Fermi breakup model generally used to describe statistical disintegration of light mass nuclei.

  15. Gaussian expansion approach to Coulomb breakup

    CERN Document Server

    Egami, T; Matsumoto, T; Iseri, Y; Kamimura, M; Yahiro, M

    2004-01-01

    An accurate treatment of Coulomb breakup reactions is presented by using both the Gaussian expansion method and the method of continuum discretized coupled channels. As $L^2$-type basis functions for describing Coulomb breakup processes, we take complex-range Gaussian functions, which form in good approximation a complete set in a large configuration space being important for the processes. Accuracy of the method is tested quantitatively for $^{8}{\\rm B}+^{58}$Ni scattering at 25.8 MeV.

  16. Description of Jet Breakup

    Science.gov (United States)

    Papageorgiou, Demetrios T.

    1996-01-01

    In this article we review recent results on the breakup of cylindrical jets of a Newtonian fluid. Capillary forces provide the main driving mechanism and our interest is in the description of the flow as the jet pinches to form drops. The approach is to describe such topological singularities by constructing local (in time and space) similarity solutions from the governing equations. This is described for breakup according to the Euler, Stokes or Navier-Stokes equations. It is found that slender jet theories can be applied when viscosity is present, but for inviscid jets the local shape of the jet at breakup is most likely of a non-slender geometry. Systems of one-dimensional models of the governing equations are solved numerically in order to illustrate these differences.

  17. Asymptotic and near-target direct breakup of 6Li and 7Li

    Science.gov (United States)

    Kalkal, Sunil; Simpson, E. C.; Luong, D. H.; Cook, K. J.; Dasgupta, M.; Hinde, D. J.; Carter, I. P.; Jeung, D. Y.; Mohanto, G.; Palshetkar, C. S.; Prasad, E.; Rafferty, D. C.; Simenel, C.; Vo-Phuoc, K.; Williams, E.; Gasques, L. R.; Gomes, P. R. S.; Linares, R.

    2016-04-01

    Background: Li,76 and 9Be are weakly bound against breakup into their cluster constituents. Breakup location is important for determining the role of breakup in above-barrier complete fusion suppression. Recent works have pointed out that experimental observables can be used to separate near-target and asymptotic breakup. Purpose: Our purpose is to distinguish near-target and asymptotic direct breakup of Li,76 in reactions with nuclei in different mass regions. Method: Charged particle coincidence measurements are carried out with pulsed Li,76 beams on 58Ni and 64Zn targets at sub-barrier energies and compared with previous measurements using 208Pb and 209Bi targets. A detector array providing a large angular coverage is used, along with time-of-flight information to give definitive particle identification of the direct breakup fragments. Results: In interactions of 6Li with 58Ni and 64Zn, direct breakup occurs only asymptotically far away from the target. However, in interactions with 208Pb and 209Bi, near-target breakup occurs in addition to asymptotic breakup. Direct breakup of 7Li into α -t is not observed in interactions with 58Ni and 64Zn. However, near-target dominated direct breakup was observed in measurements with 208Pb and 209Bi. A modified version of the Monte Carlo classical trajectory model code platypus, which explicitly takes into account lifetimes associated with unbound states, is used to simulate sub-barrier breakup reactions. Conclusions: Near-target breakup in interactions with Li,76 is an important mechanism only for the heavy targets 208Pb and 209Bi. There is insignificant near-target direct breakup of 6Li and no direct breakup of 7Li in reactions with 58Ni and 64Zn. Therefore, direct breakup is unlikely to suppress the above-barrier fusion cross section in reactions of Li,76 with 58Ni and 64Zn nuclei.

  18. Breakup branches of Borromean beryllium-9

    Energy Technology Data Exchange (ETDEWEB)

    Smith, R., E-mail: r.smith.3@pgr.bham.ac.uk; Freer, M.; Wheldon, C.; Curtis, N.; Ashwood, N. I.; Barr, M.; Kokalova, Tz.; Malcolm, J. D.; Ziman, V. A. [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom); Almaraz-Calderon, S.; Aprahamian, A.; Bucher, B.; Couder, M.; Fang, X.; Jung, F.; Lu, W.; Roberts, A.; Tan, W. P. [Institute for Structure and Nuclear Astrophysics, Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Copp, P.; Lesher, S. R. [Department of Physics, University of Wisconsin - La Crosse, La Crosse, WI 54601 (United States); and others

    2015-10-15

    The breakup reaction {sup 9}Be({sup 4}He, 3α)n was measured using an array of four double-sided silicon strip detectors at beam energies of 22 and 26 MeV. Excited states in {sup 9}Be up to 12 MeV were populated and reconstructed through the measurement of the charged reaction products. It is proposed that limits on the spins and parities of the states can be derived from the way that they decay. Various breakup paths for excited states in {sup 9}Be have been explored including the {sup 8}Be{sub g.s.} + n, {sup 8}Be{sub 2{sup +}} + n and {sup 5}He{sub g.s.} + {sup 4}He channels. By imposing the condition that the breakup proceeded via the {sup 8}Be ground state, clean excitation spectra for {sup 9}Be were reconstructed. The remaining two breakup channels were found to possess strongly-overlapping kinematic signatures and more sophisticated methods (referenced) are required to completely disentangle these other possibilities. Emphasis is placed on the development of the experimental analysis and the usefulness of Monte-Carlo simulations for this purpose.

  19. Magmatism during Gondwana breakup

    DEFF Research Database (Denmark)

    van der Meer, Quinten; Scott, J.M.; Waight, Tod Earle;

    2013-01-01

    Newly determined mid-late Cretaceous 40Ar/39Ar ages on megacrystic kaersutite from lamprophyre dikes in central and north Westland (New Zealand) are presented. These ages (88 Ma, 86 Ma and 68 Ma) indicate that the intrusion of mafic dikes was not necessarily restricted to the previously establish...... did not only precede Tasman Sea initiation (starting at ~83 Ma, lasting to ~53 Ma) but may have sporadically continued for up to 15 Myr after continental breakup....

  20. 11Li structural information from inclusive break-up measurements

    Directory of Open Access Journals (Sweden)

    Fernández-García J. P.

    2015-01-01

    Full Text Available Structure information of 11Li halo nucleus has been obtained from the inclusive break-up measurements of the 11Li+208Pb reactions at energies around the Coulomb barrier (Elab = 24.3 and 29.8 MeV. The effective break-up energy and the slope of B(E1 distribution close to the threshold have been extracted from the experimental data.

  1. Medium modifications of the nucleon--deuteron break--up cross section in the Faddeev approach

    OpenAIRE

    M. Beyer; G. Röpke; Sedrakian, A.

    1996-01-01

    The three--nucleon scattering problem in a nuclear medium is considered within the Faddeev technique. In particular the deuteron break--up cross section that governs the formation and the break--up reactions of deuterons (NNN Nd) in a nuclear environment is calculated at finite temperatures and densities. A significant enhancement of the in--medium break--up cross section with increasing density has been found.

  2. Validity test of the Trojan Horse Method applied to the {sup 7}Li+p{yields} {alpha}+{alpha} reaction via the {sup 3}He break-up

    Energy Technology Data Exchange (ETDEWEB)

    Tumino, A.; Spitaleri, C.; Sergi, M.L.; Cherubini, S.; La Cognata, M.; Lamia, L.; Romano, S.; Tudisco, S. [Universita di Catania, Dipartimento di Metodologie Fisiche e Chimiche per l' Ingegneria, Catania (Italy); INFN Laboratori Nazionali del Sud, Catania (Italy); Kroha, V.; Burjan, V.; Novac, J.; Vincour, J. [Nuclear Physics Institute of ASCR, Rez, Prague (Czech Republic); Fueloep, Z.; Somorjai, E. [Institute of Nuclear Research of Hungarian Academy of Sciences (ATOMKI), Debrecen (Hungary); Pizzone, R.G. [INFN Laboratori Nazionali del Sud, Catania (Italy)

    2006-03-15

    The Trojan Horse Method (THM) was applied to the {sup 3}He+{sup 7}Li interaction in order to investigate the quasi-free {sup 7}Li(p,{alpha}){sup 4}He reaction. The three-body experiment was performed at 33 MeV corresponding to a {sup 7}Li-p relative energy ranging from 50 keV to 7 MeV. The extracted {sup 7}Li(p,{alpha}){sup 4}He quasi-free cross-section was compared with the behavior of direct data, as well as with the result of a previous THM investigation on the {sup 7}Li(p,{alpha}){sup 4}He reaction off the neutron in {sup 2}H. A good agreement between data sets shows up throughout the energy range investigated, providing a very important validity test of the pole approximation for the THM. (orig.)

  3. Nuclear Interference effects in 8B sub-Coulomb breakup

    OpenAIRE

    Nunes, F. M.; Thompson, I.J.

    1998-01-01

    The breakup of $^8$B on $^{58}$Ni below the Coulomb barrier was measured recently with the aim of determining the Coulomb breakup components. We reexamine this reaction, and perform one step quantum-mechanical calculations that include E1, E2 and nuclear contributions. We show that the nuclear contribution is by no means negligible at the intermediate angular range where data was taken. Our results indicate that, for an accurate description of this reaction, Coulomb E1, E2 and nuclear process...

  4. Measurement of the 12C(e,e'p)11B Two-Body Breakup Reaction at High Missing Momentum Values

    CERN Document Server

    Monaghan, P; Subedi, R; Anderson, B D; Aniol, K; Annand, J; Arrington, J; Benaoum, H; Benmokhtar, F; Bertin, P; Bertozzi, W; Boeglin, W; Chen, J P; Choi, Seonho; Chudakov, E; Atti, C Ciofi degli; Cisbani, E; Cosyn, W; Craver, B; de Jager, C W; Feuerbach, R J; Folts, E; Frullani, S; Garibaldi, F; Gayou, O; Gilad, S; Gilman, R; Glamazdin, O; Gomez, J; Hansen, O; Higinbotham, D W; Holmstrom, T; Ibrahim, H; Igarashi, R; Jans, E; Jiang, X; Jiang, Y; Kaufman, L; Kelleher, A; Kolarkar, A; Kuchina, E; Kumbartzki, G; LeRose, J J; Lindgren, R; Liyanage, N; Margaziotis, D J; Markowitz, P; Marrone, S; Mazouz, M; Meekins, D; Michaels, R; Moffit, B; Morita, H; Nanda, S; Perdrisat, C F; Piasetzky, E; Potokar, M; Punjabi, V; Qiang, Y; Reinhold, J; Reitz, B; Ron, G; Rosner, G; Ryckebusch, J; Saha, A; Sawatzky, B; Segal, J; Shahinyan, A; Sirca, S; Slifer, K; Solvignon, P; Sulkosky, V; Thompson, N; Ulmer, P E; Urciuoli, G M; Voutier, E; Wang, K; Watson, J W; Weinstein, L B; Wojtsekhowski, B; Wood, S; Yao, H; Zheng, X; Zhu, L

    2013-01-01

    The five-fold differential cross section for the 12C(e,e'p)11B reaction was determined over a missing momentum range of 200-400 MeV/c, in a kinematics regime with Bjorken x > 1 and Q2 = 2.0 (GeV/c)2. A comparison of the results and theoretical models and previous lower missing momentum data is shown. The theoretical calculations agree well with the data up to a missing momentum value of 325 MeV/c and then diverge for larger missing momenta. The extracted distorted momentum distribution is shown to be consistent with previous data and extends the range of available data up to 400 MeV/c.

  5. Measurement of the 12C(e,e'p)11B Two-Body Breakup Reaction at High Missing Momentum Values

    Energy Technology Data Exchange (ETDEWEB)

    Monaghan, P; Shneor, R; Subedi, R; Anderson, B D; Aniol, K; Annand, J; Arrington, J; Benaoum, H; Benmokhtar, F; Bertin, P; Bertozzi, W; Boeglin, W; Chen, J P; Choi, Seonho; Chudakov, E; Ciofi degli-Atti, C; Cisbani, E; Cosyn, W; Craver, B; de Jager, C W; Feuerbach, R J; Folts, E; Frullani, S; Garibaldi, F; Gayou, O; Gilad, S; Gilman, R; Glamazdin, O; Gomez, J; Hansen, O; Higinbotham, D W; Holmstrom, T; Ibrahim, H; Igarashi, R; Jans, E; Jiang, X; Jiang, Y; Kaufman, L; Kelleher, A; Kolarkar, A; Kuchina, E; Kumbartzki, G; LeRose, J J; Lindgren, R; Liyanage, N; Margaziotis, D J; Markowitz, P; Marrone, S; Mazouz, M; Meekins, D; Michaels, R; Moffit, B; Morita, H; Nanda, S; Perdrisat, C F; Piasetzky, E; Potokar, M; Punjabi, V; Qiang, Y; Reinhold, J; Reitz, B; Ron, G; Rosner, G; Ryckebusch, J; Saha, A; Sawatzky, B; Segal, J; Shahinyan, A; Sirca, S; Slifer, K; Solvignon, P; Sulkosky, V; Thompson, N; Ulmer, P E; Urciuoli, G M; Voutier, E; Wang, K; Watson, J W; Weinstein, L B; Wojtsekhowski, B; Wood, S; Yao, H; Zheng, X; Zhu, L

    2014-08-01

    The five-fold differential cross section for the 12C(e,e'p)11B reaction was determined over a missing momentum range of 200-400 MeV/c, in a kinematics regime with Bjorken x > 1 and Q2 = 2.0 (GeV/c)2. A comparison of the results and theoretical models and previous lower missing momentum data is shown. The theoretical calculations agree well with the data up to a missing momentum value of 325 MeV/c and then diverge for larger missing momenta. The extracted distorted momentum distribution is shown to be consistent with previous data and extends the range of available data up to 400 MeV/c.

  6. Breakup mechanisms for 7Li + 197Au, 204Pb systems at sub-barrier energies

    Directory of Open Access Journals (Sweden)

    Luong D.H.

    2013-12-01

    Full Text Available Coincidence measurements of breakup fragments were carried out for the 7Li + 197Au and 204Pb systems at sub-barrier energies. The mechanisms triggering breakup, and time-scales of each process, were identified through the reaction Q-values and the relative energy of the breakup fragments. Binary breakup of 7Li were found to be predominantly triggered by nucleon transfer, with p-pickup leading to 8Be → α + α decay being the preferred breakup mode. From the time-scales of each process, the coincidence yields were separated into prompt and delayed components, allowing the identification of breakup process important in the suppression of complete fusion of 7Li at above-barrier energies.

  7. A new experimental approach to investigate intermediate-energy proton elastic scattering and breakup reactions on exotic nuclei in inverse kinematics

    Energy Technology Data Exchange (ETDEWEB)

    Kiselev, O.A., E-mail: Oleg.Kiselev@psi.ch [Petersburg Nuclear Physics Institute (PNPI), 188300 Gatchina (Russian Federation); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH (GSI), 64291 Darmstadt (Germany); Aksouh, F.; Bleile, A. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH (GSI), 64291 Darmstadt (Germany); Bochkarev, O.V.; Chulkov, L.V. [Kurchatov Institute, 123182 Moscow (Russian Federation); Cortina-Gil, D. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH (GSI), 64291 Darmstadt (Germany); Dobrovolsky, A.V. [Petersburg Nuclear Physics Institute (PNPI), 188300 Gatchina (Russian Federation); Egelhof, P.; Geissel, H.; Hellstroem, M. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH (GSI), 64291 Darmstadt (Germany); Isaev, N.B.; Komkov, B.G. [Petersburg Nuclear Physics Institute (PNPI), 188300 Gatchina (Russian Federation); Matos, M. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH (GSI), 64291 Darmstadt (Germany); Moroz, F.V. [Petersburg Nuclear Physics Institute (PNPI), 188300 Gatchina (Russian Federation); Muenzenberg, G. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH (GSI), 64291 Darmstadt (Germany); Mutterer, M. [Institut fuer Kernphysik (IKP), TU-Darmstadt, 64289 Darmstadt (Germany); Mylnikov, V.A. [Petersburg Nuclear Physics Institute (PNPI), 188300 Gatchina (Russian Federation); Neumaier, S.R. [GSI Helmholtzzentrum fuer Schwerionenforschung GmbH (GSI), 64291 Darmstadt (Germany); Pribora, V.N. [Kurchatov Institute, 123182 Moscow (Russian Federation); Seliverstov, D.M. [Petersburg Nuclear Physics Institute (PNPI), 188300 Gatchina (Russian Federation)

    2011-06-11

    We report on a new experimental setup for the investigation of proton induced reactions on exotic nuclei in inverse kinematics. It was installed and successfully used in the scattering study of intermediate-energy protons ({approx}700MeV/u) on neutron-rich nuclei {sup 6,8}He produced with the FRagment Separator (FRS) at the GSI facility, Darmstadt. A new pure liquid-hydrogen target was successfully adapted allowing to obtain low-background data as compared to commonly used (CH{sub 2}){sub n} targets. Absolute differential cross-sections for elastic (p,{sup 6,8}He) scattering were obtained at angles corresponding to 0.05{<=}|t|{<=}0.125 (GeV/c){sup 2} of the four-momentum transfer squared (-t) leading to the first diffraction minimum and spanning more than two orders of magnitude. They complement an earlier measurement at smaller angles 0.0025{<=}|t|{<=}0.05 (GeV/c){sup 2} performed at the same energy with an active target. Both data sets agree well in the overlap region t{approx}0.05 (GeV/c){sup 2} and enable a refined and comparative study of the radial distribution of the nuclear matter density.

  8. Percolation picture of nucleus break-up

    International Nuclear Information System (INIS)

    The production of nuclear fragments in multifragmentation and spallation reactions is viewed as a percolation phenomenon. A model of nuclear percolation is proposed. The criteria for linkage of nucleons to a cluster are defined in real and momentum spaces. In addition, ''compactness'' conditions are imposed to the clusters in both spaces. This model behaves in many respects as a two-dimensional site percolation model, exhibiting a rather well defined percolation threshold at psub(c) approximately 0.6. The concentration p is related to the number of fast particles leaving the nuclear volume. We discuss possible experimental signatures of this new break-up mechanism

  9. Breakup of molten aluminum drops

    International Nuclear Information System (INIS)

    To clarify the entrapment of water and the breakup mechanism in molten Al drops, a series of experiments was carried out by pouring molten Al of 10 to 20 g (up to 1,000degC) into a highly subcooled-water pool (room temperature) through the air. A single large-scale water jet, which is capable of penetrating a molten Al drop, was found to appear above the molten Al drop immediately after an air column which the molten drop is dragging from the water surface, is detached. It was observed with a high frequency that a molten Al drop begins swelling first, and is then broken up during falling through the water pool or after hitting the basement. It was also found that the breakup always occurs in the course of solid crust formation, and the molten drop solidified without breakup forms a large cavity inside. Based on the experimental observations, it is concluded that the swelling and the breakup of a molten Al drop should be caused by the water entrapped inside and the hydrogen remaining super-saturated. It is reasonable to consider that an intensive breakup should be caused when some quantity of water is injected into a molten Al drop with a capability that a high-pressure vapor is generated due to a rapid release of latent heat just after brittle cracks occur during swelling. (author)

  10. Study on breakup mechanism of unstable nuclei with CDCC

    CERN Document Server

    Matsumoto, T

    2015-01-01

    The continuum-discretized coupled-channels method (CDCC) has been successful in describing breakup reactions involving unstable nuclei. Moreover, CDCC is a useful method for evaluation of nuclear data, which are important for nuclear engineering. In this article, we present the theoretical foundation of CDCC and some results of CDCC analyses.

  11. New treatment of breakup continuum in the method of continuum discretized coupled channels

    CERN Document Server

    Matsumoto, T; Ogata, K; Iseri, Y; Hiyama, E; Kamimura, M; Yahiro, M

    2003-01-01

    In the method of continuum discretized coupled channels (CDCC) for treating three-body processes in projectile breakup reactions, the discretization of continuous breakup channels is essential. We propose a practical method of the discretization. The validity of the method is numerically tested and confirmed for two realistic examples, $d+^{58}$Ni scattering at 80 MeV and $^{6}Li+^{40}$Ca scattering at 156 MeV. Calculated elastic and breakup S-matrix elements based on the new method converge as the number of discretized breakup channels is increased. The converged S-matrix element agrees with the exact one which is derived with average (Av) discretization established as an accurate method. The new discretization requires a smaller number of breakup channels than the Av method. The feasibility of the new method for more complicated reactions is also discussed.

  12. Deuteron–deuteron scattering above four-nucleon breakup threshold

    Directory of Open Access Journals (Sweden)

    A. Deltuva

    2015-03-01

    Full Text Available Deuteron–deuteron elastic scattering and transfer reactions in the energy regime above four-nucleon breakup threshold are described by solving exact four-particle equations for transition operators. Several realistic nuclear interaction models are used, including the one with effective many-nucleon forces generated by the explicit Δ-isobar excitation; the Coulomb force between protons is taken into account as well. Differential cross sections, deuteron analyzing powers, outgoing nucleon polarization, and deuteron-to-neutron polarization transfer coefficients are calculated at 10 MeV deuteron energy. Overall good agreement with the experimental data is found. The importance of breakup channels is demonstrated.

  13. Inclusive breakup of Borromean nuclei

    CERN Document Server

    Hussein, Mahir S; Frederico, Tobias

    2016-01-01

    We derive the inclusive breakup cross section of a three-fragment projectile nuclei, $a = b +x_1 + x_2$, in the spectator model. The resulting four-body cross section for observing $b$, is composed of the elastic breakup cross section which contains information about the correlation between the two participant fragments, and the inclusive non-elastic breakup cross section. This latter cross section is found to be a non-trivial four-body generalization of the Austern formula \\cite{Austern1987}, which is proportional to a matrix element of the form, $\\langle\\hat{\\rho}_{{x_1},{x_2}}\\left|\\left[W_{{x_1}} + W_{{x_2}} + W_{3B}\\right]\\right|\\hat{\\rho}_{{x_1}, {x_2}}\\rangle$. The new feature here is the three-body absorption, represented by the imaginary potential, $W_{3B}$. We analyze this type of absorption and supply ideas of how to calculate its contribution.

  14. Mechanisms of Li-projectile breakup-up

    International Nuclear Information System (INIS)

    Various experimental and theoretical features observed in recent studies of break-up of 6Li and 7Li projectiles in the field of atomic nuclei are discussed, in particular for the transitional energy regime of 10-30 MeV/amu. The discussion is organized as three independent lectures presented at the International School on Nuclear Physics, Kiev (UkSSR), 28 May - 8 June, 1990. After a survey on the main experimental facts and on the basic reaction mechanisms, current theoretical approaches are illustrated by an application to the analysis of elastic break-up of 156 MeV 6Li projectiles. Finally Coulomb break-up is discussed as a novel tool of laboratory nuclear astrophysics. (orig.)

  15. Elastic Coulomb breakup of 34Na

    Science.gov (United States)

    Singh, G.; Shubhchintak, Chatterjee, R.

    2016-08-01

    Background: 34Na is conjectured to play an important role in the production of seed nuclei in the alternate r -process paths involving light neutron rich nuclei very near the β -stability line, and as such, it is important to know its ground state properties and structure to calculate rates of the reactions it might be involved in, in the stellar plasma. Found in the region of `island of inversion', its ground state might not be in agreement with normal shell model predictions. Purpose: The aim of this paper is to study the elastic Coulomb breakup of 34Na on 208Pb to give us a core of 33Na with a neutron and in the process we try and investigate the one neutron separation energy and the ground state configuration of 34Na. Method: A fully quantum mechanical Coulomb breakup theory within the architecture of post-form finite range distorted wave Born approximation extended to include the effects of deformation is used to research the elastic Coulomb breakup of 34Na on 208Pb at 100 MeV/u. The triple differential cross section calculated for the breakup is integrated over the desired components to find the total cross-section, momentum, and angular distributions as well as the average momenta, along with the energy-angular distributions. Results: The total one neutron removal cross section is calculated to test the possible ground state configurations of 34Na. The average momentum results along with energy-angular calculations indicate 34Na to have a halo structure. The parallel momentum distributions with narrow full widths at half-maxima signify the same. Conclusion: We have attempted to analyze the possible ground state configurations of 34Na and in congruity with the patterns in the `island of inversion' conclude that even without deformation, 34Na should be a neutron halo with a predominant contribution to its ground state most probably coming from 33Na(3 /2+)⊗ 2 p3 /2ν configuration. We also surmise that it would certainly be useful and rewarding to test our

  16. Observation of breakup transfer process for the bound states of {sup 16}O populated from {sup 12}C({sup 6}Li,d) reaction at 20 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Adhikari, S.; Basu, C.; Thompson, I. J.; Sugathan, P.; Jhinghan, A.; Golda, K. S.; Babu, A.; Singh, D.; Ray, S.; Mitra, A. K. [Nuclear Physics Division, Saha Institute of Nuclear Physics, Kolkata-700064 (India); Lawrence Livermore National Laboratory, L-414, Livermore CA 94551 (United States); Inter University Accelerator Centre, New Delhi 110067 (India); Physics Department, Ramkrishna Vivekananda University, Belur, Howrah (India); Nuclear Physics Division, Saha Institute of Nuclear Physics, Kolkata-700064 (India)

    2012-10-20

    The deuteron angular distribution for the {sup 12}C({sup 6}Li,d){sup 16}O* has been measured at 20 MeV populating bound and unbound states of {sup 16}O. Analysis shows a dominance of breakup induced alpha transfer in comparison to a direct alpha transfer process for the bound states. The effect increases as the excitation energy of {sup 16}O decreases, maximizing at the ground state.

  17. Elastic and break-up of the 1n-halo 11Be nucleus

    Science.gov (United States)

    Di Pietro, A.; Moro, A. M.; Acosta, L.; Amorini, F.; Borge, M. J. G.; Figuera, P.; Fisichella, M.; Fraile, L. M.; Gomez-Camacho, J.; Jeppesen, H.; Lattuada, M.; Martel, I.; Milin, M.; Musumarra, A.; Papa, M.; Pellegriti, M. G.; Perez-Bernal, F.; Raabe, R.; Randisi, G.; Rizzo, F.; Scuderi, V.; Tengblad, O.; Torresi, D.; Vidal, A. Maira; Voulot, D.; Wenander, F.; Zadro, M.

    2014-03-01

    The elastic and break-up angular distributions of the 10,11Be+64Zn reactions measured at Ec.m.≈1.4 VC have been analysed within the CCDC and O.M. frameworks. The suppression of the Coulomb-nuclear interference, observed in the 11Be scattering case with respect to the 10Be, has been interpreted as due to a long range absorption owing to the coupling with the break-up (Coulomb and nuclear) channels. The presence of 10Be events on the 11Be experiment data have been explained as due mainly to break-up processes.

  18. Elastic and break-up of the 1n-halo 11Be nucleus

    Directory of Open Access Journals (Sweden)

    Di Pietro A.

    2014-03-01

    Full Text Available The elastic and break-up angular distributions of the 10,11Be+64Zn reactions measured at Ec.m.≈1.4 VC have been analysed within the CCDC and O.M. frameworks. The suppression of the Coulomb-nuclear interference, observed in the 11Be scattering case with respect to the 10Be, has been interpreted as due to a long range absorption owing to the coupling with the break-up (Coulomb and nuclear channels. The presence of 10Be events on the 11Be experiment data have been explained as due mainly to break-up processes.

  19. Disintegration locations in 7Li→8Be transfer-triggered breakup at near-barrier energies

    Science.gov (United States)

    Simpson, E. C.; Cook, K. J.; Luong, D. H.; Kalkal, Sunil; Carter, I. P.; Dasgupta, M.; Hinde, D. J.; Williams, E.

    2016-02-01

    Background: At above-barrier energies, complete fusion cross sections in collisions of light weakly bound nuclei with heavy target nuclei are suppressed when compared to well-bound nuclei. Breakup of the projectilelike nucleus was proposed to be the cause. In addition to direct breakup, breakup following transfer was shown to be substantial. Purpose: We investigate breakup in reactions with 7Li, triggered by sub-barrier proton pickup to unbound states in 8Be, which subsequently separate into two α particles. Method: Measurements of sub-barrier disintegration of 7Li on a 58Ni target were made using the Heavy Ion Accelerator Facility at the Australian National University. Combining the experimental results with classical simulations of post-breakup acceleration, we study the sensitivity of α -α energy and angle correlations to the proximity of disintegration to the target (proton donor) nucleus. Results: The simulations indicate that disintegration as the colliding nuclei approach each other leads to large angular separations θ12 of the α fragments. The detectors allow for a maximum opening angle of θ12=132∘ , such that the present experiment is largely insensitive to breakup occurring when the collision partners approach each other. The data are consistent with disintegration of (a) the 0+8Be ground state far from the targetlike nucleus, and (b) the 2+8Be resonance near the targetlike nucleus when the 8Be is receding from the targetlike nucleus. Conclusions: The present results shed light on the near-target component of transfer-induced breakup reactions. The distribution of events with respect to the opening angle of the α particles, and the orientation of their relative velocity with respect to the velocity of their center of mass, gives insights into their proximity to the target at the moment of breakup. Further measurements with larger angular coverage and more complete simulations are required to fully understand the influence of breakup on fusion.

  20. Extracting electric dipole breakup cross section of one-neutron halo nuclei from breakup observables

    CERN Document Server

    Yoshida, Kazuki; Minomo, Kosho; Ogata, Kazuyuki

    2014-01-01

    How to extract an electric dipole (E1) breakup cross section \\sigma(E1) from one- neutron removal cross sections measured by using 12C and 208Pb targets, \\sigma_(-1n)^C and \\sigma_(-1n)^Pb, respectively, is discussed. It is shown that within about 5% error, \\sigma(E1) can be obtained by subtracting \\Gamma \\sigma_(-1n)^C from \\sigma_(- 1n)^Pb, as assumed in preceding studies. However, for the reaction of weakly-bound projectiles, the scaling factor \\Gamma is found to be two times as large as that usually adopted. As a result, we obtain 13-20% smaller \\sigma(E1) of 31Ne at 250 MeV/nucleon than extracted in a previous analysis of experimental data. By compiling the values of \\Gamma obtained for several projectiles, \\Gamma=(2.30 +/- 0.41)\\exp(- S_n)+(2.43 +/- 0.21) is obtained, where S_n is the neutron separation energy. The target mass number dependence of the nuclear parts of the one-neutron removal cross section and the elastic breakup cross section is also investigated.

  1. Microscopic Description of Diffractive Deuteron Breakup by He-3 Nuclei

    CERN Document Server

    Kovalchuk, Valery

    2016-01-01

    A microscopic formalism for describing observed cross sections for deuteron breakup by three-nucleon nuclei was developed on the basis of the diffraction nuclear model. A general formula that describes the amplitude for the reaction d+3He->3He+p+n and which involves only one adjustable parameter was obtained by using expansions of the integrands involved in terms of a Gaussian basis. This formula was used to analyze experimental data on the exclusive cross sections for deuteron breakup by He-3 nuclei at the projectile energy of 89.4 MeV. The importance of employing, in calculations, a deuteron wave function that has a correct asymptotic behavior at large nucleon-nucleon distances was demonstrated.

  2. Theoretical studies on reaction mechanisms of unstable nuclei

    International Nuclear Information System (INIS)

    Recent studies on reactions of unstable nuclei by means of the continuum-discretized coupled-channels method (CDCC) are briefly reviewed. The topics covered are: four-body breakup processes for 6He induced reaction, microscopic description of projectile breakup processes, and new approach to inclusive breakup processes. (author)

  3. Investigation of correlations in the breakup of He8

    International Nuclear Information System (INIS)

    Correlations in light neutron-rich nuclei are of considerable importance in understanding their structure. In this context the breakup of He8 into He6 + 2n has been investigated at 15 MeV/nucleon. The measurements were undertaken using a setup composed of two detector arrays: CHARISSA to detect the charged fragments and DEMON to detect the neutrons. The interpretation of the results was facilitated using a Monte Carlo simulation which was developed to take into account the correlations, the reaction and the experimental setup. Two techniques were used to study the correlations in the breakup of He8. The first, intensity interferometry, provides, via the construction of the neutron-neutron correlation function, for a first estimate of the source size and thus the average separation between the neutrons. The second, using Dalitz plots, allows both the neutron-neutron and core-neutron correlations to be probed. Here, sequential decay via the ground state resonance of He7 and has been found to dominate the dissociation of He8. The spatial and temporal characteristics of the breakup of He8 have thus been deduced and a root-mean-square separation between the two valence neutrons in the continuum states was estimated to be (7.3 ± 0.6) fm with a time delay between their emission of (1000 ± 300) fm/c. (author)

  4. Negative Emotions and Behaviors are Markers of Breakup Distress

    Science.gov (United States)

    Field, Tiffany; Diego, Miguel; Pelaez, Martha; Deeds, Osvelia; Delgado, Jeanette

    2013-01-01

    Method: University students who experienced a recent romantic breakup were given several self-report measures and were then divided into high versus low breakup distress groups. Results: The high breakup distress versus the low breakup distress groups had higher scores on negative emotions scales including depression, anxiety and anger and…

  5. Intrusive Thoughts: A Primary Variable in Breakup Distress

    Science.gov (United States)

    Field, Tiffany; Diego, Miguel; Pelaez, Martha; Deeds, Osvelia; Delgado, Jeannette

    2013-01-01

    University students who were high versus low on breakup distress scores were given self-report measures to assess their intrusive thoughts about the romantic breakup and their somatic symptoms that followed the breakup as well as their extracurricular activities and social support that might alleviate their breakup distress. In a regression…

  6. Breakup of spherical vesicles caused by spontaneous curvature change

    Institute of Scientific and Technical Information of China (English)

    Ping Liu; Ju Li; Yong-Wei Zhang

    2012-01-01

    We present our theoretical analysis and coarsegrained molecular dynamics (CGMD) simulation results to describe the mechanics of breakup of spherical vesicles driven by changes in spontaneous curvature.Systematic CGMD simulations reveal the phase diagrams for the breakup and show richness in breakup morphologies.A theoretical model based on Griffith fracture mechanics is developed and used to predict the breakup condition.

  7. Neutron Induced D Breakup in Inertial Confinement Fusion at the Omega Laser Facility

    Science.gov (United States)

    Forrest, C. J.; Glebov, V. Yu.; Knauer, J. P.; Radha, P. B.; Regan, S. P.; Sangster, T. C.; Stoeckl, C.; Schroder, W. U.; Frenje, J. A.; Gatu Johnson, M.

    2015-11-01

    High-resolution neutron spectroscopy is used to study the deuteron breakup reaction D(n,n ') np in the thermonuclear environment created in inertial confinement fusion experiments at the Omega Laser Facility. Neutrons with an energy of 14.1 MeV generated in the primary D-T fusion reactions scatter elastically and inelastically off the dense (cryogenic) D-T fuel assembly surrounding the central hot spot at peak fuel compression. These neutrons also induce a breakup of the fuel deuterons. The corresponding breakup cross section is measured relative to elastic n -D and n -T scattering, i.e., simultaneously in the same environment. Apart from astrophysical and technological interest, the neutron-induced deuteron breakup reaction is of interest to the physics of nucleon -nucleon forces. For example, theoretical calculations predict a noticeable influence of nucleonic three-body forces on the magnitude of the breakup cross section. Preliminary results from measurements of the neutron contribution in the 2- to 6-MeV range show reasonable agreement with the published ENDL 2008.2 semi-empirical cross-section. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.

  8. Study of pairing and clusterization in light nuclei through nuclear break-up

    International Nuclear Information System (INIS)

    Nuclear break-up is a powerful tool to investigate nuclear structure as it is sensitive to the quantum properties of the emitted particles. This reaction mechanism has been used to investigate several aspects of correlations. First, the case of 11Be was studied where the spectroscopic factors for the two configurations where extracted. Secondly, the spectroscopic factor for alpha clusterization in the ground state of 40Ca was measured. Finally the correlation between the two neutrons in the halo of 6He emitted through breakup reactions showed strong contribution for the di-neutron configuration. (authors)

  9. A Smoothing Method of Discrete Breakup S-matrix Elements in the Theory of Continuum-Discretized Coupled Channels

    CERN Document Server

    Matsumoto, Takuma; Ogata, Kazuyuki; Yahiro, Masanobu

    2009-01-01

    We present a practical way of smoothing discrete breakup S-matrix elements calculated by the continuum-discretized coupled-channel method (CDCC). This method makes the smoothing procedure much easier. The reliability of the smoothing method is confirmed for the three-body breakup reactions, 58Ni(d,pn) at 80 MeV and 12C(6He,4He2n) at 229.8 MeV.

  10. Elastic scattering, fusion, and breakup of light exotic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Kolata, J.J. [University of Notre Dame, Physics Department, Notre Dame, IN (United States); Guimaraes, V. [Universidade de Sao Paulo, Instituto de Fisica, Sao Paulo, SP (Brazil); Aguilera, E.F. [Instituto Nacional de Investigaciones Nucleares, Departamento de Aceleradores, Mexico, Distrito Federal (Mexico)

    2016-05-15

    The present status of fusion reactions involving light (A< 20) radioactive projectiles at energies around the Coulomb barrier (E<10 MeV per nucleon) is reviewed, emphasizing measurements made within the last decade. Data on elastic scattering (providing total reaction cross section information) and breakup channels for the involved systems, demonstrating the relationship between these and the fusion channel, are also reviewed. Similarities and differences in the behavior of fusion and total reaction cross section data concerning halo nuclei, weakly-bound but less exotic projectiles, and strongly-bound systems are discussed. One difference in the behavior of fusion excitation functions near the Coulomb barrier seems to emerge between neutron-halo and proton-halo systems. The role of charge has been investigated by comparing the fusion excitation functions, properly scaled, for different neutron- and proton-rich systems. Possible physical explanations for the observed differences are also reviewed. (orig.)

  11. Fragmentation processes in nuclear reactions

    International Nuclear Information System (INIS)

    Fragmentation processes in nuclear collisions are reviewed. The main emphasis is put on light ion breakup at nonrelativistic energies. The post- and prior-form DWBA theories are discussed. The post-form DWBA, appropriate for the ''spectator breakup'' describes elastic as well as inelastic breakup modes. This theory can also account for the stripping to unbound states. The theoretical models are compared to typical experimental results to illustrate the various possible mechanisms. It is discussed, how breakup reactions can be used to study high-lying single particle strength in the continuum; how it can yield information about momentum distributions of fragments in the nucleus. (orig.)

  12. Theory of inclusive breakup cross section for Borromean nuclei within a four-body spectator model

    CERN Document Server

    Carlson, Brett V; Hussein, Mahir S

    2016-01-01

    We develop a model to treat the inclusive non-elastic break up reactions involving weakly bound three-cluster nuclei. Borromean, two-nucleon, halo nuclei are candidates of unstable three-fragments projectiles. The model is based on the theory of inclusive breakup reactions commonly employed in the treatment of incomplete fusion and surrogate method. The theory was developed in the 80's by Ichimura, Autern and Vincent (IAV) [Phys. Rev. C 32, 431 (1985)] \\cite{IAV1985}, Udagawa and Tamura (UT)[Phys. Rev. C 24, 1348 (1981)], \\cite{UT1981} and Hussein and McVoy (HM)[Nucl. Phys. A 445, 124 (1985)], \\cite{HM1985}. We extend these three-body theories to derive an expression for the fragment yield in the reaction $A\\,(a,b)\\,X$, where the projectile is $a = x_1 + x_2 + b$. The inclusive breakup cross section is found to be the sum of a generalized four-body form of the elastic breakup cross section plus the inclusive non-elastic breakup cross section which involves the "reaction" cross section of the participant fragm...

  13. Recent developments in the eikonal description of the breakup of exotic nuclei

    CERN Document Server

    Capel, P; Esbensen, H; Fukui, T; Johnson, R C; Nunes, F M; Ogata, K

    2015-01-01

    The study of exotic nuclear structures, such as halo nuclei, is usually performed through nuclear reactions. An accurate reaction model coupled to a realistic description of the projectile is needed to correctly interpret experimental data. In this contribution, we briefly summarise the assumptions made within the modelling of reactions involving halo nuclei. We describe briefly the Continuum-Discretised Coupled Channel method (CDCC) and the Dynamical Eikonal Approximation (DEA) in particular and present a comparison between them for the breakup of 15C on Pb at 68AMeV. We show the problem faced by the models based on the eikonal approximation at low energy and detail a correction that enables their extension down to lower beam energies. A new reaction observable is also presented. It consists of the ratio between angular distributions for two different processes, such as elastic scattering and breakup. This ratio is completely independent of the reaction mechanism and hence is more sensitive to the projectile...

  14. Numerical Simulation of Multi-Phase Flow in Sodium-Water Reaction using MPS Method; Numerical Investigation of Dropret Breakup and Flow Regime (Final report of the JNC cooperative research shceme on the nuclear fuel cycle)

    OpenAIRE

    Duan, R.-O.; 越塚 誠一; 高田 孝; 山口 彰

    2004-01-01

    The JNC cooperative research scheme on the nuclear fuel cycle with The University of Tokyo has been carried out to investigate a flow regime and interfacial area density of multi-phase flow in sodium-water reaction using the Moving-Particle Semi-implicit (MPS) method.

  15. Far-field breakup of spiral waves in the plankton ecological systems

    CERN Document Server

    Liu, Quan-Xing

    2007-01-01

    For oscillatory conditions, breakup of the spiral waves far away from the spiral core (as so-called "far-field breakup") was reported in a simple activator-inhibitor model by Markus B\\"{a}r, Michal Or-Guil and Lutz Brusch [Phys. Rev. Lett. \\textbf{82}, 1160 (1999) and New J. Phys. \\textbf{6}, 5 (2004)], which is in the chemical reaction-diffusion system. In present letter, the scenario in the plankton ecological system is reported. The spatial plankton model is studied numerically by computer and we find that the far-field breakup also exists in the oceanic ecological systems over a range of diffusion coefficients of phytoplankton and zooplankton. The far-field breakup leading to the spatial chaos patterns can be verified in field observation and is useful to understand the population dynamics of oceanic ecological systems. It also indicates that the far-field breakup may be a common phenomenon in the world. Finally, we give some illumination from the ecological meaning.

  16. Nuclear-breakup mechanisms in the interaction of relativistic projectiles with heavy targets

    International Nuclear Information System (INIS)

    The breakup of a Au nucleus under bombardment with relativistic p, α, and 20Ne has been investigated in an extensive, multi-detector study. The present discussion addresses some of the many aspects of the experimental results. A broad distribution of coincident fragment masses is observed, with the total fragment kinetic energy being higher than expected for a fission mechanism for total fragment mass less than or equal to 120. The formation of light fragments is shown to be inconsistent with a binary breakup mechanism, and a multi-fragment target breakup is suggested. In general, the results indicate a broad spectrum of violence in the collisions, from gentle, leading to the production of heavy spallation products and fission, to essentially explosive, leading to multi-fragment breakup into light mas products. These aspects of the reactions represent a late-stage breakup of the target residues and are positively correlated with the violence of the initial fast stage of the collision as measured by the charged particle multiplicity

  17. Critical exponents in nucleus breakup

    International Nuclear Information System (INIS)

    In recent years the study of cluster formation has become a new field in statistical physics. Nuclear reactions with particle number change can be viewed as a cluster formation processes. Multifragmentation decay produces a power law distribution of medium size clusters. These two cluster size distributions resemble that of many others statistical cluster formation processes. We discuss now these analogies in some details

  18. Elastic Coulomb breakup of $^{34}$Na

    CERN Document Server

    Singh, G; Chatterjee, R

    2016-01-01

    Purpose : The aim of this paper is to study the elastic Coulomb breakup of $^{34}$Na on $^{208}$Pb to give us a core of $^{33}$Na with a neutron and in the process we try and investigate the one neutron separation energy and the ground state configuration of $^{34}$Na. Method : A fully quantum mechanical Coulomb breakup theory within the architecture of post-form finite range distorted wave Born approximation extended to include the effects of deformation is used to research the elastic Coulomb breakup of $^{34}$Na on $^{208}$Pb at 100 MeV/u. The triple differential cross-section calculated for the breakup is integrated over the desired components to find the total cross-section, momentum and angular distributions as well as the average momenta, along with the energy-angular distributions. Results : The total one neutron removal cross-section is calculated to test the possible ground state configurations of $^{34}$Na. The average momentum results along with energy-angular calculations indicate $^{34}$Na to ha...

  19. Projectile deformation effects in the breakup of $^{37}$Mg

    CERN Document Server

    Shubhchintak,; Shyam, R

    2015-01-01

    We study the breakup of $^{37}$Mg on Pb at 244MeV/u with the recently developed extended theory of Coulomb breakup within the post-form finite range distorted wave Born approximation that includes deformation of the projectile. Comparing our calculated cross section with the available Coulomb breakup data we determine the possible ground state configuration of $^{37}$Mg.

  20. The H + HeH(+) → He + H2(+) reaction from the ultra-cold regime to the three-body breakup: exact quantum mechanical integral cross sections and rate constants.

    Science.gov (United States)

    De Fazio, Dario

    2014-06-21

    In this work, we present a quantum mechanical scattering study of the title reaction from 1 mK to 2000 K. Total integral cross sections and thermal rate constants are compared with previous theoretical and experimental data and with simpler theoretical models to understand the range of validity of the approximations used in the previous studies. The obtained quantum reactive observables have been found to be nearly insensitive to the roto-vibrational energy of the reactants at high temperatures. More sensitive to the reactant's roto-vibrational energy are the data in the cold and ultra-cold regimes. The implications of the new data presented here in the early universe scenario are also discussed and analyzed. PMID:24810283

  1. Nuclear break-up of 11Be

    CERN Document Server

    Lima, V; Lacroix, D; Blumenfeld, Y; Bourgeois, C; Chabot, M; Chomaz, Ph; Désesquelles, P; Duflot, V; Duprat, J; Fallot, M; Frascaria, N; Grévy, S; Guillemaud-Müller, D; Roussel-Chomaz, P; Savajols, H; Sorlin, O

    2007-01-01

    The break-up of 11Be was studied at 41AMeV using a secondary beam of 11Be from the GANIL facility on a 48Ti target by measuring correlations between the 10Be core, the emitted neutrons and gamma rays. The nuclear break-up leading to the emission of a neutron at large angle in the laboratory frame is identified with the towing mode through its characteristic n-fragment correlation. The experimental spectra are compared with a model where the time dependent Schrodinger equation (TDSE) is solved for the neutron initially in the 11 Be. A good agreement is found between experiment and theory for the shapes of neutron experimental energies and angular distributions. The spectroscopic factor of the 2s orbital is tentatively extracted to be 0.46+-0.15. The neutron emission from the 1p and 1d orbitals is also studied.

  2. Breakup of Pack Ice, Antarctic Ice Shelf

    Science.gov (United States)

    1991-01-01

    Breakup of Pack Ice along the periphery of the Antarctic Ice Shelf (53.5S, 3.0E) produced this mosaic of ice floes off the Antarctic Ice Shelf. Strong offshore winds, probably associated with strong katabatic downdrafts from the interior of the continent, are seen peeling off the edges of the ice shelf into long filamets of sea ice, icebergs, bergy bits and growlers to flow northward into the South Atlantic Ocean. 53.5S, 3.0E

  3. Fractal aggregation and breakup of fine particles

    Directory of Open Access Journals (Sweden)

    Li Bingru

    2016-01-01

    Full Text Available Breakup may exert a controlling influence on particle size distributions and particles either are fractured or are eroded particle-by-particle through shear. The shear-induced breakage of fine particles in turbulent conditions is investigated using Taylor-expansion moment method. Their equations have been derived in continuous form in terms of the number density function with particle volume. It suitable for future implementation in computational fluid dynamics modeling.

  4. The Beam Break-Up Numerical Simulator

    International Nuclear Information System (INIS)

    Beam Break-Up (BBU) is a severe constraint in accelerator design, limiting beam current and quality. The control of BBU has become the focus of much research in the design of the next generation collider, recirculating and linear induction accelerators and advanced accelerators. Determining the effect on BBU of modifications to cavities, the focusing elements or the beam is frequently beyond the ability of current analytic models. A computer code was written to address this problem. The Beam Break-Up Numerical Simulator (BBUNS) was designed to numerically solve for beam break-up (BBU) due to an arbitrary transverse wakefield. BBUNS was developed to be as user friendly as possible on the Cray computer series. The user is able to control all aspects of input and output by using a single command file. In addition, the wakefield is specified by the user and read in as a table. The program can model energy variations along and within the beam, focusing magnetic field profiles can be specified, and the graphical output can be tailored. In this note we discuss BBUNS, its structure and application. Included are detailed instructions, examples and a sample session of BBUNS. This program is available for distribution. 50 refs., 18 figs., 5 tabs

  5. The Beam Break-Up Numerical Simulator

    Energy Technology Data Exchange (ETDEWEB)

    Travish, G.A.

    1989-11-01

    Beam Break-Up (BBU) is a severe constraint in accelerator design, limiting beam current and quality. The control of BBU has become the focus of much research in the design of the next generation collider, recirculating and linear induction accelerators and advanced accelerators. Determining the effect on BBU of modifications to cavities, the focusing elements or the beam is frequently beyond the ability of current analytic models. A computer code was written to address this problem. The Beam Break-Up Numerical Simulator (BBUNS) was designed to numerically solve for beam break-up (BBU) due to an arbitrary transverse wakefield. BBUNS was developed to be as user friendly as possible on the Cray computer series. The user is able to control all aspects of input and output by using a single command file. In addition, the wakefield is specified by the user and read in as a table. The program can model energy variations along and within the beam, focusing magnetic field profiles can be specified, and the graphical output can be tailored. In this note we discuss BBUNS, its structure and application. Included are detailed instructions, examples and a sample session of BBUNS. This program is available for distribution. 50 refs., 18 figs., 5 tabs.

  6. Study on the breakup length of circular impinging jet

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Circular impinging jet, which is widely used in accelerated control cooling (ACC) equipment to accelerate the cooling of hot rolled plates, is subject to breakup, and may result in undesirable cooling effect. Therefore, the jet breakup should be avoided as possible in industrial production. The objective of this study is to find the relation of the processing parameters of the ACC equipment versus the breakup length of jet with weaker turbulence. To obtain quantitative findings, not only relative experimental study but also numerical simulation was carried out. For a weaker turbulent water jet, the breakup length increases with the increase of jet diameter, as well as with the jet velocity; jet diameter has a significant effect on the breakup length for a certain flow rate when compared with jet velocity; finally a suggested correlation of the jet breakup length versus jet Weber number is presented in this study.

  7. Effects of nuclear breakup channel on fusion of 6Li+64Zn system around barrier energies

    International Nuclear Information System (INIS)

    We have studied the effects of breakup, occurring due to the nuclear interaction between weakly bound 6Li and tightly bound 64Zn isotopes, on the fusion reaction at near barrier energies within the framework of dynamic polarization potential (DPP) approach. When the nuclear induced dynamic polarization potential is taken into account sub barrier enhancement and above barrier suppression have been found which improves the matching between the fusion excitation function data and predictions for 6Li+64Zn system significantly. (author)

  8. Velocity perturbation distributions in the breakup of artificial satellites

    Science.gov (United States)

    Badhwar, Gautam D.; Tan, Arjun; Reynolds, Robert C.

    1990-01-01

    A method is presented for calculating the three orthogonal components of the velocity perturbations of satellite fragments, with a view to ascertaining the nature and intensity of the satellite breakup. The method employs three simultaneous equations furnished by changes in fragment specific energy, specific angular momentum, and plane orientation. Velocity perturbations are thereby calculated for fragments from 20 major satellite breakup events; these results, in conjunction with a technique for determining fragment masses, yield a description of the breakup process.

  9. Generation and breakup of Worthington jets after cavity collapse. Part 2. Tip breakup of stretched jets

    NARCIS (Netherlands)

    Gordillo, J.M.; Gekle, Stephan

    2010-01-01

    The capillary breakup of the high-speed Worthington jets ejected after a cavity collapse in water occurs due to the high-Reynolds-number version of the capillary end-pinching mechanism first described, in the creeping flow limit, by Stone & Leal (J. Fluid Mech., vol. 198, 1989, p. 399). Using potent

  10. 11Li Breakup on 208Pb at Energies Around the Coulomb Barrier

    DEFF Research Database (Denmark)

    Fernández-García, J.P.; Cubero, M.; Rodríguez-Gallardo, M.;

    2013-01-01

    The inclusive breakup for the 11Li+208Pb reaction at energies around the Coulomb barrier has been measured for the first time. A sizable yield of 9Li following the 11Li dissociation has been observed, even at energies well below the Coulomb barrier. Using the first-order semiclassical perturbatio...

  11. Study of the role of breakup following neutron transfer in fusion induced by 9Be at near barrier energies

    International Nuclear Information System (INIS)

    The studies on the breakup effects of weakly bound nuclei, both stable and radioactive, on fusion cross section is a subject of contemporary interest. These weakly bound nuclei have low breakup threshold (binding energy) that makes the fusion induced by these nuclei fundamentally different from that induced by tightly bound nuclei. Among these nuclei, the nucleus 9Be is very interesting because it has low break up threshold of 1.67 MeV and has a possible three body n+α+α Borromean structure. So far, numbers of experiments have been carried out to study the fusion reactions induced by 9Be on various targets at near barrier energies

  12. Assessment of deuteron-induced reaction mechanisms at low and medium energies

    OpenAIRE

    Avrigeanu V.; Avrigeanu M.

    2010-01-01

    An extended analysis of the nuclear reaction mechanisms involved in the deuterons interaction with 63,65Cu is presented. First, the available elastic-scattering data analysis provided us the optical potential for reaction cross sections calculations. An increased effort has been devoted to the breakup mechanism, both the elastic breakup and the breakup fusion contributions to the different activation cross sections being carefully considered. Next, the direct reaction contributions throu...

  13. Continuum-discretized coupled-channels method for four-body nuclear breakup in $^6$He+$^{12}$C scattering

    CERN Document Server

    Matsumoto, T; Ogata, K; Iseri, Y; Kamimura, M; Chiba, S; Yahiro, M

    2004-01-01

    We propose a fully quantum-mechanical method of treating four-body nuclear breakup processes in scattering of a projectile consisting of three constituents, by extending the continuum-discretized coupled-channels method. The three-body continuum states of the projectile are discretized by diagonalizing the internal Hamiltonian of the projectile with the Gaussian basis functions. For $^6$He+$^{12}$C scattering at 18 and 229.8 MeV, the validity of the method is tested by convergence of the elastic and breakup cross sections with respect to increasing the number of the basis functions. Effects of the four-body breakup and the Borromean structure of $^6$He on the elastic and total reaction cross sections are discussed.

  14. Breakup Effects on University Students' Perceived Academic Performance

    Science.gov (United States)

    Field, Tiffany; Diego, Miguel; Pelaez, Martha; Deeds, Osvelia; Delgado, Jeannette

    2012-01-01

    The Problem: Problems that might be expected to affect perceived academic performance were studied in a sample of 283 university students. Results: Breakup Distress Scale scores, less time since the breakup and no new relationship contributed to 16% of the variance on perceived academic performance. Variables that were related to academic…

  15. University Students' Experiences of Nonmarital Breakups: A Grounded Theory

    Science.gov (United States)

    Hebert, Sarah; Popadiuk, Natalee

    2008-01-01

    Prior nonmarital breakup research has been focused on negative outcomes, rarely examining the personal growth aspects of this experience. In this study, we used a qualitative grounded theory methodology to explore the changes that university students reported experiencing as a result of a heterosexual nonmarital breakup and how those changes…

  16. 24 CFR 982.315 - Family break-up.

    Science.gov (United States)

    2010-04-01

    ... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Family break-up. 982.315 Section... SECTION 8 TENANT BASED ASSISTANCE: HOUSING CHOICE VOUCHER PROGRAM Leasing a Unit § 982.315 Family break-up... assistance in the program if the family breaks up. The PHA administrative plan must state PHA policies on...

  17. Comment on breakup densities of hot nuclei

    International Nuclear Information System (INIS)

    In [V.E. Viola et al., Phys. Rev. Lett. 93 (2004) 132701, D.S. Bracken et al., Phys. Rev. C 69 (2004) 034612] the observed decrease in spectral peak energies of IMFs emitted from hot nuclei was interpreted in terms of a breakup density that decreased with increasing excitation energy. Subsequently, Raduta et al. [Ad. Raduta et al., Phys. Lett. B 623 (2005) 43] performed MMM simulations that showed decreasing spectral peaks could be obtained at constant density. In this Letter we point out that this apparent inconsistency is due to a selective comparison of theory and data that overlooks the evolution of the fragment multiplicities as a function of excitation energy

  18. Systematic study of complete fusion suppression in reactions involving weakly bound nuclei at energies above the Coulomb barrier

    CERN Document Server

    Wang, Bing; Diaz-Torres, Alexis; Zhao, En-Guang; Zhou, Shan-Gui

    2016-01-01

    Complete fusion excitation functions of reactions involving breakup are studied by using the empirical coupled-channel (ECC) model with breakup effects considered. An exponential function with two parameters is adopted to describe the prompt-breakup probability in the ECC model. These two parameters are fixed by fitting the measured prompt-breakup probability or the complete fusion cross sections. The suppression of complete fusion at energies above the Coulomb barrier is studied by comparing the data with the predictions from the ECC model without the breakup channel considered. The results show that the suppression of complete fusion are roughly independent of the target for the reactions involving the same projectile.

  19. Eikonal reaction theory for two-neutron removal reactions

    CERN Document Server

    Minomo, K; Egashira, K; Ogata, K; Yahiro, M

    2014-01-01

    The eikonal reaction theory (ERT) proposed lately is a method of calculating one-neutron removal reactions at intermediate incident energies in which Coulomb breakup is treated accurately with the continuum discretized coupled-channels method. ERT is extended to two-neutron removal reactions. ERT reproduces measured one- and two-neutron removal cross sections for 6He scattering on 12C and 208Pb targets at 240 MeV/nucleon and also on a 28Si target at 52 MeV/nucleon. For the heavier target in which Coulomb breakup is important, ERT yields much better agreement with the measured cross sections than the Glauber model.

  20. Breakup of Spiral Waves in Coupled Hindmarsh-Rose Neurons

    Institute of Scientific and Technical Information of China (English)

    MA Jun; JIA Ya; TANG Jun; YANG Li-Jian

    2008-01-01

    @@ Breakup of spiral wave in the Hindmarsh-Rose neurons with nearest-neighbour couplings is reported.Appropriate initial values and parameter regions are selected to develop a stable spiral wave and then the Gauesian coloured noise with different intensities and correlation times is imposed on all neurons to study the breakup of spiral wave, respectively.Based on the mean field theory, the statistical factor of synchronization is defined to analyse the evolution of spiral wave.It is found that the stable rotating spiral wave encounters breakup with increasing intensity of Gaussian coloured noise or decreasing correlation time to certain threshold.

  1. Numerical analysis of jet breakup behavior using particle method

    International Nuclear Information System (INIS)

    A continuous jet changes to droplets where jet breakup occurs. In this study, two-dimensional numerical analysis of jet breakup is performed using the MPS method (Moving Particle Semi-implicit Method) which is a particle method for incompressible flows. The continuous fluid surrounding the jet is neglected. Dependencies of the jet breakup length on the Weber number and the Froude number agree with the experiment. The size distribution of droplets is in agreement with the Nukiyama-Tanasawa distribution which has been widely used as an experimental correlation. Effects of the Weber number and the Froude number on the size distribution are also obtained. (author)

  2. Numerical analysis of jet breakup behavior using particle method

    International Nuclear Information System (INIS)

    A continuous jet changes to droplets where jet breakup occurs. In this study, two-dimensional numerical analysis of jet breakup is performed using the MPS method (Moving Particle Semi-implicit Method) which is a particle method for incompressible flows. The continuous fluid surrounding the jet is neglected. Dependencies of the jet breakup length on the Waber number and the Froude number agree with the experiment. The size distribution of droplets is in agreement with the Nukiyama-Tanasawa distribution which has been widely used as an experimental correlation. Effects of the Weber number and the Froude number on the size distribution are also obtained. (author)

  3. Numerical analysis of jet breakup behavior using particle method

    International Nuclear Information System (INIS)

    A continuous jet changes to droplets where jet breakup occurs. In this study, two-dimensional numerical analysis of jet breakup is performed using the MPS method (Moving Particle Semi-implicit Method) which is a particle method for incompressible flows. The continuous fluid surrounding the jet is neglected. Dependencies of the jet breakup length on the Weber number and the Froude number agree with the experiment. The size distribution of droplets is in agreement with the Nukiyama-Tanasawa distribution that has been widely used as an experimental correlation. Effects of the Weber number and the Froude number on the size distribution are also obtained. (author)

  4. The TAB method for numerical calculation of spray droplet breakup

    Science.gov (United States)

    Orourke, P. J.; Amsden, A. A.

    A short history is given of the major milestones in the development of the stochastic particle method for calculating liquid fuel sprays. The most recent advance has been the discovery of the importance of drop breakup in engine sprays. A new method, called TAB, for calculating drop breakup is presented. Some theoretical properties of the method are derived; its numerical implementation in the computer program KIVA is described; and comparisons are presented between TAB-method calculations and experiments and calculations using another breakup model.

  5. A novel particle tracking and break-up detection algorithm: application to the turbulent break-up of bubbles

    OpenAIRE

    Rodríguez Rodríguez, Javier; Martínez Bazán, Carlos; Montañés García, José Luis

    2003-01-01

    A new method has been developed to measure experimentally the break-up properties of bubbles. The technique is based on the application of a particle tracking velocimetry algorithm to high-speed video images not only to measure the velocity of the bubbles, but also to detect the break-up events. Thus the algorithm is able to associate every broken bubble with the daughter bubbles formed upon their corresponding break-up. Moreover, the lifetime, as well as the number and size of fragments resu...

  6. Breakup of spiral wave under different boundary conditions

    Institute of Scientific and Technical Information of China (English)

    Zhao Ying-Kui; Wang Guang-Rui; Chen Shi-Gang

    2007-01-01

    In this paper, we investigate the breakup of spiral wave under no-flux, periodic and Dirichlet boundary conditions respectively. When the parameter ε is close to a critical value for Doppler-induced wave breakup, the instability of the system caused by the boundary effect occurs in the last two cases, resulting in the breakup of spiral wave near the boundary. With our defined average order measure of spiral wave (AOMSW), we quantify the degree of order of the system when the boundary-induced breakup of spiral wave happens. By analysing the AOMSW and outer diameter R of the spiral tip orbit, it is easy to find that this boundary effect is correlated with large values of R, especially under the Dirichlet boundary condition. This correlation is nonlinear, so the AOMSW sometimes oscillates with the variation of ε.

  7. Study on the breakup lengths of free round liquid jets

    Institute of Scientific and Technical Information of China (English)

    ZHU Ying; WAN Yun-xia; HUANG Yong; PENG Xin-ke

    2007-01-01

    An experiment was conducted to measure the breakup lengths of water jets with a high-speed video camera for Weber numbers from 0 to about 1.1 × 103. The initial jet diameters are changed from 0.3mm to 1.0mm. The results indicate that at low jet velocity the breakup lengths of the jets are increased linearly from 0 to a maximum value. At the Weber number about 20 the breakup length of the jet reaches its maximum value for different initial jet diameter. A computation based on the dispersion equation is conducted to study the relationship between the growth rate of the jet surface wave and the maximum breakup length. The computations show that the maximum growth rate for the axisymmetric surface wave has a turning point at Weber number about 20, and that agrees well with the experiments.

  8. Properties of nuclear and Coulomb breakup of 8B

    CERN Document Server

    Ogata, K; Iseri, Y; Yahiro, M

    2008-01-01

    Dependence of breakup cross sections of 8B at 65 MeV/nucleon on target mass number A_T is investigated by means of the continuum-discretized coupled-channels method (CDCC) with more reliable distorting potentials than in preceding study. The scaling law of the nuclear breakup cross section as A_T^(1/3) is found to be satisfied only in the middle A_T region of 40 < A_T < 150. Interference between nuclear and Coulomb breakup amplitudes turns out to vanish at very forward angles with respect to the center-of-mass of 8B, independent of target nucleus. Truncation of the relative energy between the p and 7Be fragments slightly reduces contribution from nuclear breakup at very forward angles, while the angular region in which the first-order perturbation theory works well does not change essentially.

  9. Capillary Breakup of a Liquid Bridge: Identifying Regimes and Transitions

    CERN Document Server

    Li, Yuan

    2016-01-01

    Computations of the breakup of a liquid bridge are used to establish the limits of applicability of similarity solutions derived for different breakup regimes. These regimes are based on particular viscous-inertial balances, that is different limits of the Ohnesorge number $Oh$. To accurately establish the transitions between regimes, the minimum bridge radius is resolved through four orders of magnitude using a purpose-built multiscale finite element method. This allows us to construct a quantitative phase diagram for the breakup phenomenon which includes the appearance of a recently discovered low-$Oh$ viscous regime. The method used to quantify the accuracy of the similarity solutions allows us to identify a number of previously unobserved features of the breakup, most notably an oscillatory convergence towards the viscous-inertial similarity solution. Finally, we discuss how the new findings open up a number of challenges for both theoretical and experimental analysis.

  10. Breakup and coalescence characteristics of a hollow cone swirling spray

    Science.gov (United States)

    Saha, Abhishek; Lee, Joshua D.; Basu, Saptarshi; Kumar, Ranganathan

    2012-12-01

    This paper deals with an experimental study of the breakup characteristics of water emanating from hollow cone hydraulic injector nozzles induced by pressure-swirling. The experiments were conducted using two nozzles with different orifice diameters 0.3 mm and 0.5 mm and injection pressures (0.3-4 MPa) which correspond to Rep = 7000-26 000. Two types of laser diagnostic techniques were utilized: shadowgraph and phase Doppler particle anemometry for a complete study of the atomization process. Measurements that were made in the spray in both axial and radial directions indicate that both velocity and average droplet diameter profiles are highly dependent on the nozzle characteristics, Weber number and Reynolds number. The spatial variation of diameter and velocity arises principally due to primary breakup of liquid films and subsequent secondary breakup of large droplets due to aerodynamic shear. Downstream of the nozzle, coalescence of droplets due to collision was also found to be significant. Different types of liquid film breakup were considered and found to match well with the theory. Secondary breakup due to shear was also studied theoretically and compared to the experimental data. Coalescence probability at different axial and radial locations was computed to explain the experimental results. The spray is subdivided into three zones: near the nozzle, a zone consisting of film and ligament regime, where primary breakup and some secondary breakup take place; a second zone where the secondary breakup process continues, but weakens, and the centrifugal dispersion becomes dominant; and a third zone away from the spray where coalescence is dominant. Each regime has been analyzed in detail, characterized by timescale and Weber number and validated using experimental data.

  11. Vibrating Breakup of Jet for Uniform Metal Droplets

    Institute of Scientific and Technical Information of China (English)

    Shengdong GAO; Yingxue YAO; Chengsong CUI

    2007-01-01

    Uniform droplet formation from capillary stream breakup provides promising opportunities for many applications such as solder balls manufacturing, circuit board printing and rapid prototype manufacturing. In this study an apparatus capable of making monosize metal spheres by vibrating breakup has been developed. The droplets were electrically charged to avoid collision and merging with one another during flight. As a result, uniformly sized tin powders (180μm in diameter) were obtained after cooling and solidification.

  12. Numerical simulation of mechanical breakup of river ice-cover

    Institute of Scientific and Technical Information of China (English)

    WANG Jun; HE Liang; CHEN Pang-pang; SUI Jueyi

    2013-01-01

    Ice jams and ice dams in rivers will cause significant rises of water levels.Under extreme conditions,the ice flooding during winter or early spring may occur.In this paper,by considering the fluid-solid coupling effect caused by the water and the ice cover,the mechanisms of the mechanical breakup of the river ice cover are studied.A formula is obtained for determining whether or not the mechanical breakup process would happen under the hydraulic pressure of the flow.Combined with the hydraulic model under the ice covered flow,a numerical model is built and the interaction between the discharge,the hydraulic pressure under the ice cover and the date for the mechanical breakup of the river ice cover is simulated.The simulated results of the dates for the mechanical breakup of the river ice cover agree very well with the field observations of the breakups of the river ice cover in the Hequ Reach of the Yellow River.Therefore,the numerical model might serve as a good preliminary step in studying the breakup of the river ice-cover,evidencing many important parameters that affect the ice-cover process.

  13. Role of the direct mechanisms in the deuteron-induced surrogate reactions

    CERN Document Server

    Avrigeanu, M

    2015-01-01

    An extended analysis of the key role of direct interactions, i.e., breakup, stripping and pick-up processes, for the deuteron–induced surrogate reactions is presented. Particular comments concern the deuteron breakup which is dominant in the case of the ( d; p g ) surrogate reactions on actinides target nuclei, around the Coulomb barrier.

  14. Middle-High Latitude N2O Distributions Related to the Arctic Vortex Breakup

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The relationship of N2O distributions with the Arctic vortex breakup is first analyzed with a probability distribution function (PDF) analysis. The N2O concentration shows different distributions between the early and late vortex breakup years. In the early breakup years, the N2O concentration shows low values and large dispersions after the vortex breakup, which is related to the inhomogeneity in the vertical advection in the middle and high latitude lower stratosphere. The horizontal diffusion coefficient (Kyy)shows a larger value accordingly. In the late breakup years, the N2O concentration shows high values and more uniform distributions than in the early years after the vortex breakup, with a smaller vertical advection and Kyy after the vortex breakup. It is found that the N2O distributions are largely affected by the Arctic vortex breakup time but the dynamically defined vortex breakup time is not the only factor.

  15. Neutron-neutron quasifree scattering in nd breakup at 10 MeV

    Science.gov (United States)

    Malone, R. C.; Crowe, B.; Crowell, A. S.; Cumberbatch, L. C.; Esterline, J. H.; Fallin, B. A.; Friesen, F. Q. L.; Han, Z.; Howell, C. R.; Markoff, D.; Ticehurst, D.; Tornow, W.; Witała, H.

    2016-03-01

    The neutron-deuteron (nd) breakup reaction provides a rich environment for testing theoretical models of the neutron-neutron (nn) interaction. Current theoretical predictions based on rigorous ab-initio calculations agree well with most experimental data for this system, but there remain a few notable discrepancies. The cross section for nn quasifree (QFS) scattering is one such anomaly. Two recent experiments reported cross sections for this particular nd breakup configuration that exceed theoretical calculations by almost 20% at incident neutron energies of 26 and 25 MeV [1, 2]. The theoretical values can be brought into agreement with these results by increasing the strength of the 1S0 nn potential matrix element by roughly 10%. However, this modification of the nn effective range parameter and/or the 1S0 scattering length causes substantial charge-symmetry breaking in the nucleon-nucleon force and suggests the possibility of a weakly bound di-neutron state [3]. We are conducting new measurements of the cross section for nn QFS in nd breakup. The measurements are performed at incident neutron beam energies below 20 MeV. The neutron beam is produced via the 2H(d, n)3He reaction. The target is a deuterated plastic cylinder. Our measurements utilize time-of-flight techniques with a pulsed neutron beam and detection of the two emitted neutrons in coincidence. A description of our initial measurements at 10 MeV for a single scattering angle will be presented along with preliminary results. Also, plans for measurements at other energies with broad angular coverage will be discussed.

  16. Investigation on Electrostatical Breakup of Bio-Oil Droplets

    Directory of Open Access Journals (Sweden)

    John Z. Wen

    2012-10-01

    Full Text Available In electrostatic atomization, the input electrical energy causes breaking up of the droplet surface by utilizing a mutual repulsion of net charges accumulating on that surface. In this work a number of key parameters controlling the bio-oil droplet breakup process are identified and these correlations among the droplet size distribution, specific charges of droplets and externally applied electrical voltages are quantified. Theoretical considerations of the bag or strip breakup mechanism of biodiesel droplets experiencing electrostatic potential are compared to experimental outcomes. The theoretical analysis suggests the droplet breakup process is governed by the Rayleigh instability condition, which reveals the effects of droplets size, specific charge, surface tension force, and droplet velocities. Experiments confirm that the average droplet diameters decrease with increasing specific charges and this decreasing tendency is non-monotonic due to the motion of satellite drops in the non-uniform electrical field. The measured specific charges are found to be smaller than the theoretical values. And the energy transformation from the electrical energy to surface energy, in addition to the energy loss, Taylor instability breakup, non-excess polarization and some system errors, accounts for this discrepancy. The electrostatic force is the dominant factor controlling the mechanism of biodiesel breakup in electrostatic atomization.

  17. Dynamics of bubble breakup at a T junction

    Science.gov (United States)

    Lu, Yutao; Fu, Taotao; Zhu, Chunying; Ma, Youguang; Li, Huai Z.

    2016-02-01

    The gas-liquid interfacial dynamics of bubble breakup in a T junction was investigated. Four regimes were observed for a bubble passing through the T junction. It was identified by the stop flow that a critical width of the bubble neck existed: if the minimum width of the bubble neck was less than the critical value, the breakup was irreversible and fast; while if the minimum width of the bubble neck was larger than the critical value, the breakup was reversible and slow. The fast breakup was driven by the surface tension and liquid inertia and is independent of the operating conditions. The minimum width of the bubble neck could be scaled with the remaining time as a power law with an exponent of 0.22 in the beginning and of 0.5 approaching the final fast pinch-off. The slow breakup was driven by the continuous phase and the gas-liquid interface was in the equilibrium stage. Before the appearance of the tunnel, the width of the depression region could be scaled with the time as a power law with an exponent of 0.75; while after that, the width of the depression was a logarithmic function with the time.

  18. Breakup of 42 MeV 7Li projectiles in the fields of 12C and 197Au nuclei

    Indian Academy of Sciences (India)

    Dhruba Gupta; C Samanta; R Kanungo; P Basu; Subinit Roy; S Kailas; A Chatterjee; B J Roy; K Mahata; A Samant; A Shrivastava

    2001-07-01

    Inclusive cross sections of particles and tritons from the breakup of 42 MeV 7Li by 12C and 197Au targets are presented and analysed in the framework of the Serber model. Spectral distortions due to the targets and relevant reaction mechanisms are discussed.

  19. Breakup of Droplets in Micro and Nanofluidic T-Junctions

    Directory of Open Access Journals (Sweden)

    A. bedram

    2013-01-01

    Full Text Available We employ numerical simulations to investigate the breakup of droplets in micro- and nanoscale T junctions, which are used to produce small droplets from a large droplet. For this purpose a Volume f Fluid (VOF based method is used and for verifying the reliability of the numerical outcomes, the results are compared with the available experimental and analytical results. Our results reveal that breakup time and breakup length of the droplets play important roles in handling these systems optimally. Our results also indicate that for nanoscale Tjunctions by increasing the capillary number the performance increases while for the micro-scale systems there is a specific capillary number for which the system is in its optimum condition.

  20. Coulomb and Nuclear Breakup at Low Energies: Scaling Laws

    Directory of Open Access Journals (Sweden)

    Hussein M. S.

    2013-12-01

    Full Text Available We report on a recent work on the low-energy behavior of the breakup cross section in so far as it has important role in the fusion of weakly bound and halo nuclei at near-barrier energies. We assess the way the nuclear component of this cross section scales with the target mass. In complete accord with previous finding at higher energies we verify that the low energy behavior of the breakup cross section for a given projectile and relative center of mass energy with respect to the Coulomb barrier height scales as the cubic root of the mass number of the target. Surprisingly we find that the Coulomb component of the breakup cross section at these low energies also obeys scaling, but with a linear dependence on the target charge. Our findings are important when planning for experiments involving these exotic nuclei.

  1. Scaling laws for near barrier Coulomb and Nuclear Breakup

    CERN Document Server

    Hussein, M S; Lubian, J; Otomar, D R; Canto, L F

    2013-01-01

    We investigate the nuclear and the Coulomb contributions to the breakup cross sections of $^6$Li in collisions with targets in different mass ranges. Comparing cross sections for different targets at collision energies corresponding to the same $E/V_{\\mathrm{\\scriptscriptstyle B}}$, we obtain interesting scaling laws. First, we derive an approximate linear expression for the nuclear breakup cross section as a function of $A_{\\mathrm{% \\scriptscriptstyle T}}^{1/3}$. We then confirm the validity of this expression performing CDCC calculations. Scaling laws for the Coulomb breakup cross section are also investigated. In this case, our CDCC calculations indicate that this cross section has a linear dependence on the atomic number of the target. This behavior is explained by qualitative arguments. Our findings, which are consistent with previously obtained results for higher energies, are important when planning for experiments involving exotic weakly bound nuclei.

  2. New technique for high-speed microjet breakup analysis

    Energy Technology Data Exchange (ETDEWEB)

    Vago, N. [Department of Atomic Physics, Budapest University of Technology and Economics, Budafoki ut 8, 1111, Budapest (Hungary); Synova SA, Ch. Dent d' Oche, 1024 Ecublens (Switzerland); Spiegel, A. [Department of Atomic Physics, Budapest University of Technology and Economics, Budafoki ut 8, 1111, Budapest (Hungary); Couty, P. [Institute of Imaging and Applied Optics, Swiss Federal Institute of Technology, Lausanne, BM, 1015, Lausanne (Switzerland); Wagner, F.R.; Richerzhagen, B. [Synova SA, Ch. Dent d' Oche, 1024 Ecublens (Switzerland)

    2003-10-01

    In this paper we introduce a new technique for visualizing the breakup of thin high-speed liquid jets. Focused light of a He-Ne laser is coupled into a water jet, which behaves as a cylindrical waveguide until the point where the amplitude of surface waves is large enough to scatter out the light from the jet. Observing the jet from a direction perpendicular to its axis, the light that appears indicates the location of breakup. Real-time examination and also statistical analysis of the jet disruption is possible with this method. A ray tracing method was developed to demonstrate the light scattering process. (orig.)

  3. Experimental Investigation on Breakup of Ice Floe on Waves

    Institute of Scientific and Technical Information of China (English)

    WANG Yongxue; LI Chunhua; LI Guangwei; SHEN Zhaowei

    2000-01-01

    Experimental investigation of ice floe breakup on waves by use of non-refrigerated breakable materials has been carried out. The incident wave heights for breakup of ice floe with different lengths, and the influence of rigidity on reflection and transmission coefficients are discussed. The experimental results show that the ratio of the ice floe length, Li, to the wavelength, L, is one of the significant factor affecting the minimum wave height to cause fracture of ice floe, and another key factor is the ratio of the ice floethickness, hi and Li.

  4. On the breakup of tectonic plates by polar wandering

    Science.gov (United States)

    Liu, H.-S.

    1974-01-01

    The equations for the stresses in a homogeneous shell of uniform thickness caused by a shift of the axis of rotation are derived. The magnitude of these stresses reaches a maximum value of the order of 10 to the 9th power dyn/sq cm, which is sufficient for explaining a tectonic breakup. In order to deduce the fracture pattern according to which the breakup of tectonic plates can be expected the theory of plastic deformation of shells is applied. The analysis of this pattern gives an explanation of the existing boundary systems of the major tectonic plates as described by Morgan (1968), LePichon (1968) and Isacks et al. (1968).

  5. Microscopic analysis of 10,11Be elastic scattering on protons and 12C and breakup processes of 11Be within the 10Be+n cluster model

    Science.gov (United States)

    Spasova, K.; Lukyanov, V. K.; Kadrev, D. N.; Antonov, A. N.; Zemlyanaya, E. V.; Lukyanov, K. V.; Gaidarov, M. K.

    2016-06-01

    The elastic scattering cross-sections of 10,11Be on protons and 12C at energy E NN interactions, while the imaginary OP is estimated within the high energy approximation (HEA). The spin-orbit part of the OP is also included. The characteristics of the breakup processes of 11Be on different nuclear targets are also considered. The cross-sections of diffractive breakup and stripping reactions of 11Be on 9Be, 93Nb, 181Ta and 238U at energy E = 63 MeV/nucleon and the longitudinal momentum distributions of 10Be fragments produced in the breakup of 11Be on these nuclei are presented. The results are in a good agreement with the available experimental data, in particular the obtained widths of about 50 MeV/c are closed to the empirical ones.

  6. Neutrino Magnetic Moment Contribution to the Neutrino-Deuteron Reaction

    OpenAIRE

    Tsuji, K.; Nakamura, S.; Sato, T.; Kubodera, K.; Myhrer, F.

    2004-01-01

    We study the effect of the neutrino magnetic moment on the neutrino-deuteron breakup reaction, using a method called the standard nuclear physics approach, which has already been well tested for several electroweak processes involving the deuteron.

  7. Inclusive deuteron-induced reactions and final neutron states

    CERN Document Server

    Potel, Gregory; Thompson, Ian J

    2015-01-01

    We present in this paper a formalism for deuteron-induced inclusive reactions. We disentangle direct elastic breakup contributions from other processes (which we generically call non-elastic breakup) implying a capture of the neutron both above and below the neutron emission threshold. The reaction is described as a two step process, namely the breakup of the deuteron followed by the propagation of the neutron-target system driven by an optical potential. The final state interaction between the neutron and the target can eventually form an excited compound nucleus. Within this context, the direct neutron transfer to a sharp bound state is a limiting case of the present formalism.

  8. Microscopic effective reaction theory for direct nuclear reactions

    Directory of Open Access Journals (Sweden)

    Ogata Kazuyuki

    2016-01-01

    Full Text Available Some recent activities with the microscopic effective reaction theory (MERT on elastic, inelastic, breakup, transfer, and knockout processes are reviewed briefly. As a possible alternative to MERT, a description of elastic and inelastic scattering with the continuum particle-vibration coupling (cPVC method is also discussed.

  9. Complete kinematical study of the 3α breakup of the 16.11 MeV state in 12C

    Science.gov (United States)

    Laursen, K. L.; Fynbo, H. O. U.; Kirsebom, O. S.; Madsbøll, K. S.; Riisager, K.

    2016-09-01

    The reaction 11 B + p has been used to populate the (J^{π},T) = (2+,1) state at an excitation energy of 16.11 MeV in 12C, and the breakup of the state into three α-particles has been studied in complete kinematics. A two-step breakup model which includes interference effects is found to provide the most accurate description of the experimental data. The branching ratio to the ground state of 8Be is determined to be 5.1(5)% in agreement with previous findings, but more precise by a factor of two, while the decay to the first excited state in 8Be is found to be dominated by d-wave emission.

  10. Complete kinematical study of the 3$\\alpha$ breakup of the 16.11 MeV state in $^{12}$C

    CERN Document Server

    Laursen, K L; Kirsebom, O S; Madsbøl, K O; Riisager, K

    2016-01-01

    The reaction $^{11}B+p$ has been used to populate the $(J^{\\pi},T)=(2^+,1)$ state at an excitation energy of 16.11 MeV in $^{12}$C, and the breakup of the state into three $\\alpha$ particles has been studied in complete kinematics. A two-step breakup model which includes interference effects is found to provide the most accurate description of the experimental data. The branching ratio to the ground state of $^8$Be is determined to be 5.1(5)% in agreement with previous findings, but more precise by a factor of two, while the decay to the first-excited state in $^8$Be is found to be dominated by $d$-wave emission.

  11. Elastic and inelastic breakup of deuterons with energy below 100 MeV

    CERN Document Server

    Carlson, B V; Sin, M

    2015-01-01

    We present calculations of deuteron elastic and inelastic breakup cross sections and angular distributions at deuteron energies below 100 MeV obtained using the post-form DWBA approximation. The elastic breakup cross section was extensively studied in the past. Very few calculations of inelastic breakup have been performed, however. We also analyze the angular momentum - energy distributions of the cross section for formation of the compound nucleus after inelastic breakup.

  12. Instability and breakup of cavitation bubbles within diesel drops

    Institute of Scientific and Technical Information of China (English)

    Ming Lü; Zhi Ning; Kai Yan; Juan Fu; Chunhua Sun

    2015-01-01

    A modified mathematical model is used to study the effects of various forces on the stability of cavitation bubbles within a diesel droplet. The principal finding of the work is that viscous forces of fluids stabilize the cavitation bubble, while inertial force destabilizes the cavitation bubble. The droplet viscosity plays a dominant role on the stability of cavitation bubbles compared with that of air and bubble. Bubble–droplet radius ratio is a key factor to control the bubble stability, especially in the high radius ratio range. Internal hydrodynamic and surface tension forces are found to stabilize the cavitation bubble, while bubble stability has little relationship with the external hydrodynamic force. Inertia makes bubble breakup easily, however, the breakup time is only slightly changed when bubble growth speed reaches a certain value (50 m·s−1). In contrast, viscous force makes bubble hard to break. With the increasing initial bubble–droplet radius ratio, the bubble growth rate increases, the bubble breakup radius decreases, and the bubble breakup time becomes shorter.

  13. Breakup of New Orleans Households after Hurricane Katrina

    Science.gov (United States)

    Rendall, Michael S.

    2011-01-01

    Theory and evidence on disaster-induced population displacement have focused on individual and population-subgroup characteristics. Less is known about impacts on households. I estimate excess incidence of household breakup resulting from Hurricane Katrina by comparing a probability sample of pre-Katrina New Orleans resident adult household heads…

  14. Structural Stability of the Coalescence/Breakup Equation.

    Science.gov (United States)

    Brown, Philip S., Jr.

    1995-11-01

    An analysis of the structural stability of the coalescence/breakup equation is performed to determine the degree to which changes in the equation's formulation can affect the solution. The work was motivated by speculation in various quarters that the currently used coalescence/breakup formulation should be adjusted to achieve better agreement between solutions and field observations. Both analytical procedures and numerical experiments, in which hypothetical changes in the rate coefficients are assumed, show the coalescence/breakup equation in its current formulation to be structurally stable. Not only do small changes in the rate coefficients produce negligible change in the solutions, but even large changes in the rate coefficients fail to destroy the fundamental behavior of the system in that all solutions continue to approach a unique equilibrium. Moderate-sized perturbations of the coefficients are found to have only minor influence on the solutions unless the coalescence and breakup efficiencies, constituents of the rate coefficients, are perturbed in an opposite sense to reinforce the individual effects. Only with such changes in the formulation is the equilibrium solution found to be altered to a significant degree.

  15. Influence of projectile breakup on complete fusion

    Indian Academy of Sciences (India)

    A Mukherjee; M K Pradhan

    2010-07-01

    Complete fusion excitation functions for 11,10B+159Tb and 6,7Li+159Tb have been reported at energies around the respective Coulomb barriers. The measurements show significant suppression of complete fusion cross-sections at energies above the barrier for 10B+159Tb and 6,7Li+159Tb reactions, when compared to those for 11B+159Tb. The comparison shows that the extent of suppression of complete fusion cross-sections is correlated with the -separation energies of the projectiles. Also, the measured incomplete fusion cross-sections show that the -particle emanating channel is the favoured incomplete fusion process. Inclusive measurement of the -particles produced in 6Li+159Tb reaction has been carried out. Preliminary CDCC calculations carried out to estimate the - yield following 6Li breaking up into + fail to explain the measured -yield. Transfer processes seem to be important contributors.

  16. Direct measurement of stellar neutron capture rates of 14C and comparison with the Coulomb breakup method

    Science.gov (United States)

    Reifarth, Rene; Heil, M.; Plag, R.; Besserer, U.; Couture, A.; Dababneh, S.; Dörr, L.; Forssén, C.; Görres, J.; Haight, R. C.; Mengoni, A.; O'Brien, S.; Patronis, N.; Rundberg, R. S.; Uberseder, E.; Wiescher, M.; Wilhelmy, J. B.

    The neutron capture cross section of 14 C has been shown to be important for several neutron driven nucleosynthesis scenarios. Due to the high neutron abundance it is expected that the 14 C(n,γ) reaction competes strongly with other neutron-induced reactions on 14 C. The 14 C(n,γ) reaction is also important to validate (n,γ) cross sections obtained via the inverse reaction by the Coulomb breakup method. In principle, 14 C belongs to the few cases where this correspondence can be validated in a convincingly clean way. So far, the example of 14 C is obscured, however, by discrepancies between several experiments and theory. In this contribution we report on a re- analysis of the direct measurements of the 14 C(n,γ) reaction presented on the last NIC conference (Vancouver, 2004). The neutron energies used during the experiment ranged from 30 to 800 keV. The earlier presented disagreement between the direct measurements and the Coulomb breakup method has been resolved.

  17. Development and validation of models for bubble coalescence and breakup

    International Nuclear Information System (INIS)

    A generalized model for bubble coalescence and breakup has been developed, which is based on a comprehensive survey of existing theories and models. One important feature of the model is that all important mechanisms leading to bubble coalescence and breakup in a turbulent gas-liquid flow are considered. The new model is tested extensively in a 1D Test Solver and a 3D CFD code ANSYS CFX for the case of vertical gas-liquid pipe flow under adiabatic conditions, respectively. Two kinds of extensions of the standard multi-fluid model, i.e. the discrete population model and the inhomogeneous MUSIG (multiple-size group) model, are available in the two solvers, respectively. These extensions with suitable closure models such as those for coalescence and breakup are able to predict the evolution of bubble size distribution in dispersed flows and to overcome the mono-dispersed flow limitation of the standard multi-fluid model. For the validation of the model the high quality database of the TOPFLOW L12 experiments for air-water flow in a vertical pipe was employed. A wide range of test points, which cover the bubbly flow, turbulent-churn flow as well as the transition regime, is involved in the simulations. The comparison between the simulated results such as bubble size distribution, gas velocity and volume fraction and the measured ones indicates a generally good agreement for all selected test points. As the superficial gas velocity increases, bubble size distribution evolves via coalescence dominant regimes first, then breakup-dominant regimes and finally turns into a bimodal distribution. The tendency of the evolution is well reproduced by the model. However, the tendency is almost always overestimated, i.e. too much coalescence in the coalescence dominant case while too much breakup in breakup dominant ones. The reason of this problem is discussed by studying the contribution of each coalescence and breakup mechanism at different test points. The redistribution of the

  18. Breakup characteristics of a liquid jet in subsonic crossflow

    Science.gov (United States)

    Gopala, Yogish

    This thesis describes an experimental investigation of the breakup processes involved in the formation of a spray created by a liquid jet injected into a gaseous crossflow. This work is motivated by the utilization of this method to inject fuel in combustors and afterburners of airplane engines. This study aims to develop a better understanding of the spray breakup processes and to provide better experimental inputs to improve the fidelity of numerical models. A review of the literature in this field identified the fundamental physical processes involved in the breakup of the spray and the dependence of spray properties on operating conditions. The time taken for the liquid column to break up into ligaments and droplets, the primary breakup time and the effect of injector geometry on the spray formation processes and spray properties as the key research areas in which research done so far has been inadequate. Determination of the location where the liquid column broke up was made difficult by the presence of a large number of droplets surrounding it. This study utilizes the liquid jet light guiding technique that enables accurate measurements of this location for a wide range of operating conditions. Prior to this study, the primary breakup time was thought to be a function the density ratio of the liquid and the gas, the diameter of the orifice and the air velocity. This study found that the time to breakup of the liquid column depends on the Reynolds number of the liquid jet. This suggests that the breakup of a turbulent liquid jet is influenced by both the aerodynamic breakup processes and the turbulent breakup processes. Observations of the phenomenon of the liquid jet splitting up into two or more jets were made at some operating conditions with the aid of the new visualization technique. Finally, this thesis investigates the effect of injector geometry on spray characteristics. One injector was a round edged orifice with a length to diameter ratio of 1 and a

  19. Laser-induced break-up of water jet waveguide

    Energy Technology Data Exchange (ETDEWEB)

    Couty, P.; Hoffmann, P. [EPFL/STI/IOA/Advanced Photonics Laboratory, Lausanne BM, 1015, Lausanne (Switzerland); Spiegel, A.; Vago, N. [Department of Atomic Physics, Budapest University of Technology and Economics, Budafoki ut 8, 1111, Budapest (Hungary); Ugurtas, B.I. [EPFL/STI/IMHEF/Laboratory Fluid Mechanics, Lausanne, 1015, Lausanne (Switzerland)

    2004-06-01

    In this article, an optical method to control the break-up of high-speed liquid jets is proposed. The method consists of focusing the light of a pulsed laser source into the jet behaving as a waveguide. Experiments were performed with the help of a Q-switched frequency doubled Nd:Yag laser ({lambda}=532 nm). The jet diameter was 48 {mu}m and jet velocities from 100 to 200 m/s. To study the laser-induced water jet break-up, observations of the jet coupled with the high power laser were performed for variable coupling and jet velocity conditions. Experimentally determined wavelength and growth rate of the laser-generated disturbance were also compared with the ones predicted by linear stability theory of free jets. (orig.)

  20. Breakup of small aggregates driven by turbulent hydrodynamic stress

    CERN Document Server

    Babler, Matthaus U; Lanotte, Alessandra S

    2012-01-01

    Breakup of small solid aggregates in homogeneous and isotropic turbulence is studied theoretically and by using Direct Numerical Simulations at high Reynolds number, Re_{\\lambda} \\simeq 400. We show that turbulent fluctuations of the hydrodynamic stress along the aggregate trajectory play a key role in determining the aggregate mass distribution function. Differences between turbulent and laminar flows are discussed. A novel definition of the fragmentation rate is proposed in terms of the typical frequency at which the hydrodynamic stress becomes sufficiently high to cause breakup along each Lagrangian path. We also define an Eulerian proxy of the real fragmentation rate, based on the joint statistics of the stress and its time derivative, which should be easier to measure in any experimental set-up. Both our Eulerian and Lagrangian formulations define a clear procedure for the computation of the mass distribution function due to fragmentation. Contrary, previous estimates based only on single point statistic...

  1. Numerical modeling of dimethyl ether (DME) bubble growth and breakup

    Institute of Scientific and Technical Information of China (English)

    ZHANG Peng; ZHANG YuSheng

    2009-01-01

    A numerical program is written to simulate the process of vapor bubble growth with spherical symmetry from the thermodynamic critical radius in an initially uniformly superheated liquid. The program is validated by the experimental data of superheated water. The calculated results agree with those of experiments well. The program takes into account the variations of properties with temperature precisely to simulate the DME bubble growth under flash boiling conditions. Considering the influences of pressure, surface tension and viscous stress, the linear stability analysis method is adopted to deduce the dispersion equation to represent the disturbance development during the bubble growth, and a new criterion for bubble breakup is established. The results show the bubble becomes more unstable with the increase of bubble Weber number and void fraction, and that with the increase of bubble growth rate or the decrease of initial radius ration of droplet to bubble, the breakup time of bubble becomes shorter.

  2. Improvement of Jet Breakup Model in Fuel Coolant Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Bang, Kwang Hyun; Kim, Kyung Kyu; Nam, Yang Ho [Korea Maritime Univ., Jinhae (Korea, Republic of)

    2007-02-15

    The objective of this work is to improve TRACER-II code in conjunction with the OECD SERENA project for validation of vapor explosion analysis codes. FCI breakup model is to be improved by building four-fluid multiphase flow model and existing models and experimental data are examined for the validation of the model. Four-fluid multiphase flow model has been built in TRACER-II code and jet breakup model has been included. Kelvin-Helmholtz instability is modelled for the jet side and boundary layer stripping is modelled for the jet leading edge. This work can contributes to the reduction of uncertainty in the FCI models for reactor safety analysis.

  3. Semiclassical treatment of fusion and breakup processes of ^{6,8}He halo nuclei

    Science.gov (United States)

    Majeed, Fouad A.; Abdul-Hussien, Yousif A.

    2016-06-01

    A semiclassical approach has been used to study the effect of channel coupling on the calculations of the total fusion reaction cross section σ _{fus}, and the fusion barrier distribution D_{fus} for the systems 6He +^{238}U and 8He +^{197}Au. Since these systems invloves light exotic nuclei, breakup states channel play an important role that should be considered in the calculations. In semiclassical treatment, the relative motion between the projectile and target nuclei is approximated by a classical trajectory while the intrinsic dynamics is handled by time-dependent quantum mechanics. The calculations of the total fusion cross section σ _{fus}, and the fusion barrier distribution D_{fus} are compared with the full quantum mechanical calculations using the coupled-channels calculations with all order coupling using the computer code and with the available experimental data.

  4. Study on breakup behavior of molten material JET in coolant

    International Nuclear Information System (INIS)

    It is important to estimate the jet breakup behavior of the molten core material jet in coolant during a core distractive accident (CDA) of a fast breeder reactor (FBR). In the present study, the molten jet of U-alloy 78 simulating the core material is injected into the water simulating the coolant. The visual data of the molten jet breakup behavior is observed by using the high-speed video camera. The front velocity of the molten jet is estimated by using the image processing technique from the visual data. It shows that the front velocity of the molten jet can be divided into three regions in time. In first region, the front velocity of the molten jet increases. In second region, the front velocity of the molten jet suddenly decreases. In third region, the front velocity of the molten jet keeps at low and steady. In first region, the column diameter of the molten jet decreases with the passage of time. At the location between first region and second region, the column of the molten jet breaks up and disappears. It is experimentally observed that the molten material column in the molten material jet from breaks up and disappears as the border time between the first and the second regions. In the present study, the jet breakup length is defined as the distance from the water surface to the location between the first and the second regions, since the main body of the molten material jet column is fragmented at the time and location. From the present experimental results, it is clarified that the jet breakup behavior depends on the injection nozzle diameter but independs on the penetration velocity of the molten material jet. The present experimental results are different from qualitative tendency of the formula by Saito at al. but are qualitatively similar by Epstein et al.. (author)

  5. Inverted Break-up Behaviour in Continuous Inkjet (CIJ) Printing

    Science.gov (United States)

    McIlroy, Claire; Harlen, Oliver; Morrison, Neil

    2014-11-01

    Although droplet creation during continuous jetting of Newtonian fluids has been widely studied, unsolved problems surrounding the break-up dynamics remain. Jetting through a nozzle creates a stream of liquid that is rendered unstable by surface tension. This instability creates a succession of main drops connected by thin filaments, with drop separation determined by the fastest growing wavelength. In order to control break-up and increase printing speeds, continuous inkjet (CIJ) printing exploits the effects of finite amplitude modulations in the jet velocity profile giving conditions where jet stability deviates from the usual Rayleigh behaviour. To explore these non-linear effects, we have developed a one-dimensional jetting model. In particular, we identify a modulation range for which pinching occurs upstream of the connecting filament, rather than downstream - a phenomenon we call ``inverted'' break-up. Furthermore, this behaviour can be controlled by the addition of harmonics to the initial driving signal. Our results are compared to full axisymmetric simulations in order to incorporate the effects of nozzle geometry. EPSRC Innovation in Industrial Technology.

  6. Some features of spray breakup in effervescent atomizers

    Energy Technology Data Exchange (ETDEWEB)

    Gadgil, Hrishikesh P.; Raghunandan, B.N. [Indian Institute of Science, Department of Aerospace Engineering, Bangalore (India)

    2011-02-15

    The near orifice spray breakup at low GLR (gas to liquid ratio by mass) values in an effervescent atomizer is studied experimentally using water as a simulant and air as atomizing gas. From the visualizations, the near orifice spray structures are classified into three modes: discrete bubble explosions, continuous bubble explosions and annular conical spray. The breakup of the spray is quantified in terms of the mean bubble bursting distance from the orifice. The parametric study indicates that the mean bubble bursting distance mainly depends on airflow rate, jet diameter and mixture velocity. It is also observed that the jet diameter has a dominant effect on the bubble bursting distance when compared to mixture velocity at a given airflow rate. The mean bubble bursting distance is shown to be governed by a nondimensional two-phase flow number consisting of all the aforementioned parameters. The location of bubble bursting is found to be highly unsteady spatially, which is influenced by flow dynamics inside the injector. It is proposed that this unsteadiness in jet breakup length is a consequence of varying degree of bubble expansion caused due to the intermittent occurrence of single phase and two-phase flow inside the orifice. (orig.)

  7. Breakup length of harmonically stimulated capillary jets - theory and experiments

    Science.gov (United States)

    Garcia Garcia, Francisco Javier; Gonzalez Garcia, Heliodoro; Castrejon-Pita, Jose Rafael; Castrejon-Pita, Alfonso Arturo

    2014-11-01

    A stream of liquid breaks up into several drops by the action of surface tension. Capillary breakup forms the basis of some modern digital technologies, especially inkjet printing (including 3D manufacturing). Therefore, the control and prediction of the breakup length of harmonically modulated capillary jets is of great importance, in particular in Continuous InkJet systems (CIJ). However, a theoretical model that rigorously takes into account the physical characteristics of the system, and that properly describes this phenomenon did not exist until now. In this work we present a simple transfer function, derived from first principles, that accurately predicts the experimentally obtained breakup lengths of pressure-modulated capillary jets. No fitting parameters are necessary. A detailed description of the theoretical model and experimental setup will be presented. Spanish government (FIS2011-25161), Junta de Andalucia (P09-FQM-4584 and P11-FQM-7919), EPSRC-UK (EP/H018913/1), Royal Society and John Fell Fund (OUP).

  8. Nonlinear dynamics and breakup of free-surface flows

    International Nuclear Information System (INIS)

    Surface-tension-driven flows and, in particular, their tendency to decay spontaneously into drops have long fascinated naturalists, the earliest systematic experiments dating back to the beginning of the 19th century. Linear stability theory governs the onset of breakup and was developed by Rayleigh, Plateau, and Maxwell. However, only recently has attention turned to the nonlinear behavior in the vicinity of the singular point where a drop separates. The increased attention is due to a number of recent and increasingly refined experiments, as well as to a host of technological applications, ranging from printing to mixing and fiber spinning. The description of drop separation becomes possible because jet motion turns out to be effectively governed by one-dimensional equations, which still contain most of the richness of the original dynamics. In addition, an attraction for physicists lies in the fact that the separation singularity is governed by universal scaling laws, which constitute an asymptotic solution of the Navier-Stokes equation before and after breakup. The Navier-Stokes equation is thus continued uniquely through the singularity. At high viscosities, a series of noise-driven instabilities has been observed, which are a nested superposition of singularities of the same universal form. At low viscosities, there is rich scaling behavior in addition to aesthetically pleasing breakup patterns driven by capillary waves. The author reviews the theoretical development of this field alongside recent experimental work, and outlines unsolved problems. copyright 1997 The American Physical Society

  9. A methodology of MSL breakup analysis for Earth accidental reentry and its application to breakup analysis for Mars off-nominal entry

    Science.gov (United States)

    Salama, Ahmed; Ling, Lisa

    2005-01-01

    Vehicle breakup analysis has been performed for missions that may carry nuclear fuel for heating or power purposes to assess nuclear safety in case of launch failure leading to atmospheric reentry. Also, failure scenarios exist which could lead to breakup during Entry / Descent / Landing (EDL) at Mars due to off-nominal entries, with implications for planetary protection requirements. Since the Mars Science Laboratory (MSL) spacecraft may include a Multi-Mission Radioisotope Thermoelectric Generator (MMRTG), an analysis of breakup in case of launch failure is required. Also, breakup during Mars EDL due to off-nominal entries could release the RTG heat source that has implications for planetary protection requirements. This paper presents a methodology of MSL breakup analysis for launch failure with application to Mars off-nominal entry.

  10. Elastic break-up of 156 MeV 6Li projectiles with large asymptotic relative momenta of the fragments

    International Nuclear Information System (INIS)

    The triple differential cross sections for elastic break-up of 156 MeV 6Li projectiles by the reactions 208Pb (6Li, ad) 208Pbg.s., and 12C (6Li, ad) 12Cg.s. have been measured with large asymptotic relative momenta of the outgoing fragments. The data exhibit rather unfamiliar shapes of the energy spectra, often replacing the usual bell-shape distributions by double-peaked structures and varying rapidly with the relative emission angles. The origin of these features has been explored and the cross sections have been analysed on the basis of a diffractive disintegration approach. (orig.)

  11. The Effect of Corporate Break-ups on Information Asymmetry: A Market Microstructure Analysis

    OpenAIRE

    Bardong, Florian; Bartram, Söhnke M.; Yadav, Pradeep K.

    2006-01-01

    This paper investigates the information environment during and after a corporate break-up utilizing direct measures of information asymmetry developed in the market microstructure literature. The analysis is based on all corporate break-ups in the United States in the period 1995-2005. The results document that information asymmetry declines significantly as a result of a break-up. However, this reduction takes place not at the time of its announcement or its completion, but after it has been...

  12. MODEL OF SEA ICE BREAKUP ON SHALLOW BEACH DUE TO TIDAL FLUCTUATION

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    There are many factors that may lead to the breakup of shore fast ice, such as wind, wave, tide and so on.This paper mainly analyzed the ice breakup on the shallow beach due to tidal fluctuation.The theoretical model was set up and the fitting range was given.The calculated result shows that the slope angle α, the ice thickness h, and the ice length l are key factors in determining the ice breakup length lp.

  13. Bag-breakup control of surface drag in hurricanes

    Science.gov (United States)

    Troitskaya, Yuliya; Zilitinkevich, Sergej; Kandaurov, Alexander; Ermakova, Olga; Kozlov, Dmitry; Sergeev, Daniil

    2016-04-01

    Air-sea interaction at extreme winds is of special interest now in connection with the problem of the sea surface drag reduction at the wind speed exceeding 30-35 m/s. This phenomenon predicted by Emanuel (1995) and confirmed by a number of field (e.g., Powell, et al, 2003) and laboratory (Donelan et al, 2004) experiments still waits its physical explanation. Several papers attributed the drag reduction to spume droplets - spray turning off the crests of breaking waves (e.g., Kudryavtsev, Makin, 2011, Bao, et al, 2011). The fluxes associated with the spray are determined by the rate of droplet production at the surface quantified by the sea spray generation function (SSGF), defined as the number of spray particles of radius r produced from the unit area of water surface in unit time. However, the mechanism of spume droplets' formation is unknown and empirical estimates of SSGF varied over six orders of magnitude; therefore, the production rate of large sea spray droplets is not adequately described and there are significant uncertainties in estimations of exchange processes in hurricanes. Herewith, it is unknown what is air-sea interface and how water is fragmented to spray at hurricane wind. Using high-speed video, we observed mechanisms of production of spume droplets at strong winds by high-speed video filming, investigated statistics and compared their efficiency. Experiments showed, that the generation of the spume droplets near the wave crest is caused by the following events: bursting of submerged bubbles, generation and breakup of "projections" and "bag breakup". Statistical analysis of results of these experiments showed that the main mechanism of spray-generation is attributed to "bag-breakup mechanism", namely, inflating and consequent blowing of short-lived, sail-like pieces of the water-surface film. Using high-speed video, we show that at hurricane winds the main mechanism of spray production is attributed to "bag-breakup", namely, inflating and

  14. Experimental study on breakup characteristics of molten jet falling in gas plenum and water pool

    Energy Technology Data Exchange (ETDEWEB)

    Akinaga, Makoto; Kurita, Tomohisa; Yokobori, Seiichi [Toshiba Corp., Kawasaki, Kanagawa (Japan)

    2001-07-01

    The breakup characteristics of liquid jet issuing to air plenum and flowing into liquid pool were experimentally clarified. The jet breakup behavior around air was classified varying liquid substance. The bismuth and stannum molten jet was found to maintain its original shape. Moreover, breakup behavior of this molten jet during falling into the water pool was visualized. From the lump sedimented to the bottom, break-up behavior was found to be affected by the water subcooling which determining the balance between boiling and solidifying. (author)

  15. Experimental study on breakup characteristics of molten jet falling in gas plenum and water pool

    International Nuclear Information System (INIS)

    The breakup characteristics of liquid jet issuing to air plenum and flowing into liquid pool were experimentally clarified. The jet breakup behavior around air was classified varying liquid substance. The bismuth and stannum molten jet was found to maintain its original shape. Moreover, breakup behavior of this molten jet during falling into the water pool was visualized. From the lump sedimented to the bottom, break-up behavior was found to be affected by the water subcooling which determining the balance between boiling and solidifying. (author)

  16. Application of Multiphase Particle Methods in Atomization and Breakup Regimes of Liquid Jets

    CERN Document Server

    Farrokhpanah, Amirsaman

    2016-01-01

    Multiphase Smoothed Particle Hydrodynamics (SPH) method has been used to study the jet breakup phenomena. It has been shown that this method is well capable of capturing different jet breakup characteristics. The value obtained for critical Weber number here in transition from dripping to jetting is a very good match to available values in literature. Jet breakup lengths are also agreeing well with several empirical correlations. Successful usage of SPH, as a comparably fast CFD solver, in jet breakup analysis helps in speeding up the numerical study of this phenomenon.

  17. Breakup conditions of projectile spectators from dynamical observables

    Energy Technology Data Exchange (ETDEWEB)

    Begemann-Blaich, M.; Lindenstruth, V.; Pochodzalla, J. [and others

    1998-03-01

    Momenta and masses of heavy projectile fragments (Z {>=} 8), produced in collisions of {sup 197}Au with C, Al, Cu and Pb targets at E/A=600 MeV, were determined with the ALADIN magnetic spectrometer at SIS. Using these informations, an analysis of kinematic correlations between the two and three heaviest projectile fragments in their rest frame was performed. The sensitivity of these correlations to the conditions at breakup was verified within the schematic SOS-model. For a quantitative investigation, the data were compared to calculations with statistical multifragmentation models and to classical three-body calculations. With classical trajectory calculations, where the charges and masses of the fragments are taken from a Monte Carlo sampling of the experimental events, the dynamical observables can be reproduced. The deduced breakup parameters, however, differ considerably from those assumed in the statistical multifragmentation models which describe the charge correlations. If, on the other hand, the analysis of kinematic and charge correlations is performed for events with two and three heavy fragments produced by statistical multifragmentation codes, a good agreement with the data is found with the exception that the fluctuation widths of the intrinsic fragment energies are significantly underestimated. A new version of the multifragmentation code MCFRAG was therefore used to investigate the potential role of angular momentum at the breakup stage. If a mean angular momentum of 0.75 {Dirac_h}/nucleon is added to the system, the energy fluctuations can be reproduced, but at the same time the charge partitions are modified and deviate from the data. (orig.)

  18. Breakup conditions of projectile spectators from dynamical observables

    International Nuclear Information System (INIS)

    Momenta and masses of heavy projectile fragments (Z ≥ 8), produced in collisions of 197Au with C, Al, Cu and Pb targets at E/A=600 MeV, were determined with the ALADIN magnetic spectrometer at SIS. Using these informations, an analysis of kinematic correlations between the two and three heaviest projectile fragments in their rest frame was performed. The sensitivity of these correlations to the conditions at breakup was verified within the schematic SOS-model. For a quantitative investigation, the data were compared to calculations with statistical multifragmentation models and to classical three-body calculations. With classical trajectory calculations, where the charges and masses of the fragments are taken from a Monte Carlo sampling of the experimental events, the dynamical observables can be reproduced. The deduced breakup parameters, however, differ considerably from those assumed in the statistical multifragmentation models which describe the charge correlations. If, on the other hand, the analysis of kinematic and charge correlations is performed for events with two and three heavy fragments produced by statistical multifragmentation codes, a good agreement with the data is found with the exception that the fluctuation widths of the intrinsic fragment energies are significantly underestimated. A new version of the multifragmentation code MCFRAG was therefore used to investigate the potential role of angular momentum at the breakup stage. If a mean angular momentum of 0.75 ℎ/nucleon is added to the system, the energy fluctuations can be reproduced, but at the same time the charge partitions are modified and deviate from the data. (orig.)

  19. The Breakup of Temperature Inversions In Steep Valleys

    Science.gov (United States)

    Colette, A.; Street, R.

    The purpose of this research is to model and provide a better understanding of tem- perature inversions breakup in steep valleys. The Advanced Regional Prediction Sys- tem (ARPS), a three-dimensional, compressible, and non-hydrostatic modeling tool developed by the Center for Analysis and Prediction of Storms at the University of Oklahoma was used. Many field studies indicate that the evolution of the convective and inversion layers are strongly dependant on the surrounding topography. In relatively open valleys, the convective boundary layer usually grows from the bottom of the valley while in steeper cases, the upslope morning winds affects the dynamic of the mixing layer resulting in the destruction of the inversion from its bottom and its top (see Whiteman 1980). ARPS allows one to perform accurate simulation of such situations. First, written in terrain following coordinates, it handles steep topographies; then its extensive radi- ation and surface flux packages provide a good treatment of land related processes. Moreover, ARPS accounts for the incidence angle of sunrays, differencing the ex- posed and non-exposed mountain slopes. However, it neglects the topographic shade which can delay the sunrise of a hour or more in steep valleys. A new subroutine described by Colette etal. 2002 is thus used to compute the projected shade on the surrounding topography. Simulations of temperature inversion breakup for various two-dimensional valleys are presented. The time scale of evolution of the mixing layer is in good agreement with field studies and, as expected, the convective boundary layer shows an asymmetry between east and west facing slopes. The different patterns of inversion breakup doc- umented by Whiteman are also reproduced. These simulations of idealized cases give a better understanding of inversion breakup in steep valleys. Our code is now being applied to a real case: the study of a peculiar wind, la Ora del Garda, caused by the interaction between a

  20. Bubble breakup in two-dimensional Stokes flow

    International Nuclear Information System (INIS)

    A new class of exact solutions is reported for an evolving bubble in a two-dimensional slow viscous flow. It is observed that for an expanding bubble the interface grows smoother with time, whereas the contracting-bubble solutions display a tendency to form sharp corners (''near cusps'') for small values of surface tension. In the latter case, we also obtain analytic solutions that describe bubble breakup: For a large class of initial shapes, the interface will eventually develop a thin ''neck'' whose width goes to zero before the bubble is completely removed from the liquid

  1. Dynamical Relativistic Effects in Breakup Processes of Halo Nuclei

    CERN Document Server

    Ogata, Kazuyuki

    2009-01-01

    The continuum-discretized coupled-channels (CDCC) method is used to study the breakup of weakly-bound nuclei at intermediate energies collisions. For large impact parameters, the Eikonal CDCC (E-CDCC) method was applied. The effects of Lorentz contraction on the nuclear and Coulomb potentials have been investigated in details. Such effects tend to increase cross sections appreciably. We also show that, for loosely-bound nuclei, the contribution of the so-called close field is small and can be neglected.

  2. Chaotic behaviour as a signal of nuclear breakup

    International Nuclear Information System (INIS)

    The nuclear breakup process is studied under the assumption that the energy transfer between the target and the projectile nucleus in the peripheral collisions can induce a chaotic behaviour of the nuclear Fermi systems, provided by the matching between the Woods - Saxon wall frequency and the uni - nucleonic frequency oscillation. Such a behaviour could be emphasized by uni-nucleonic phase - space maps, Poincare maps, power spectra, autocorrelation function and Lyapunov exponents ranging the nuclear interaction time scale: 10-22 s - 10-23 s. It is also shown that this method could be applied for various different fields and problems regarding nuclear dynamics. (authors)

  3. Investigation of the Deuteron Breakup on Proton Target in the Forward Angular Region at 130 MeV

    International Nuclear Information System (INIS)

    A set of differential cross-section data of the 1H(d, pp)n breakup reaction at 130 MeV deuteron beam energy has been measured in the domain of very forward polar angles with the use of the Germanium Wall detector at the Forschungszentrum Jülich. The data obtained for over 1000 kinematical points (112 geometries) are compared with the theoretical predictions based on various models of the three-nucleon (3N) dynamics. They comprise: the realistic nucleon-nucleon potentials alone or combined with the three-nucleon force (3NF), the coupled-channel calculations with the explicit treatment of the Δ-isobar excitation and finally, the potentials derived from chiral perturbation theory. In the part of the phase space studied, the Coulomb interaction between protons has a strong impact on the differential cross section of the breakup reaction. The strongest Coulomb effects are found in regions where the relative energy of the two protons is the smallest. In these regions the data are well reproduced exclusively by calculations which include the electromagnetic repulsion between protons. In spite of the dominance of the Coulomb force in the phase space studied, the contribution of 3NF effects is also observed. (author)

  4. Break-up dynamics of fluctuating liquid threads.

    Science.gov (United States)

    Petit, Julien; Rivière, David; Kellay, Hamid; Delville, Jean-Pierre

    2012-11-01

    The thinning dynamics of a liquid neck before break-up, as may happen when a drop detaches from a faucet or a capillary, follows different rules and dynamic scaling laws depending on the importance of inertia, viscous stresses, or capillary forces. If now the thinning neck reaches dimensions comparable to the thermally excited interfacial fluctuations, as for nanojet break-up or the fragmentation of thermally annealed nanowires, these fluctuations should play a dominant role according to recent theory and observations. Using near-critical interfaces, we here fully characterize the universal dynamics of this thermal fluctuation-dominated regime and demonstrate that the cross-over from the classical two-fluid pinch-off scenario of a liquid thread to the fluctuation-dominated regime occurs at a well-defined neck radius proportional to the thermal length scale. Investigating satellite drop formation, we also show that at the level of the cross-over between these two regimes it is more probable to produce monodisperse droplets because fluctuation-dominated pinch-off may allow the unique situation where satellite drop formation can be inhibited. Nonetheless, the interplay between the evolution of the neck profiles from the classical to the fluctuation-dominated regime and the satellites' production remains to be clarified. PMID:23090994

  5. Role of projectile breakup effects and intrinsic degrees of freedom on fusion dynamics

    Science.gov (United States)

    Singh Gautam, Manjeet

    2016-05-01

    This article analyzes the fusion dynamics of loosely bound and stable projectiles with Zr-target isotopes within the context of the coupled channel approach and the energy-dependent Woods-Saxon potential model (EDWSP model). In the case of the 28Si + 90Zr reaction, the coupling to the inelastic surface excitations results in an adequate description of the observed fusion dynamics while in case of the 28Si + 94Zr reaction, the coupling to collective surface vibrational states as well as the neutron (multi-neutron) transfer channel is necessary in the coupled channel calculations to reproduce the below-barrier fusion data. However, the EDWSP model calculation provides an accurate explanation of the fusion data of 28Si + 90,94Zr reactions in the domain of the Coulomb barrier. In the fusion of the 6Li + 90Zr reaction, the inclusion of the nuclear structure degrees of freedom recovers the observed sub-barrier fusion enhancement but results in suppression of the above barrier fusion data by 34% with respect to the coupled channel calculations. Using EDWSP model calculations, this suppression factor is reduced by 14% and consequently, the above-barrier fusion data of 6Li + 90Zr reaction is suppressed by 20% with reference to the EDWSP model calculations. Such fusion suppression at above-barrier energies can be correlated with the breakup of the projectile (6Li) before reaching the fusion barrier, as a consequence of low binding energy. Supported by Dr. D. S. Kothari Post-Doctoral Fellowship Scheme sponsored by University Grants Commission (UGC), New Delhi, India

  6. Numerical simulation of particle fluxes formation generated as a result of space objects breakups in orbit

    Science.gov (United States)

    Aleksandrova, A. G.; Galushina, T. Yu.

    2015-12-01

    The paper describes the software package developed for the numerical simulation of the breakups of natural and artificial objects and algorithms on which it is based. A new software "Numerical model of breakups" includes models of collapse of the spacecraft (SC) as a result of the explosion and collision as well as two models of the explosion of an asteroid.

  7. Restructuring and Break-Up of Two-Dimensional Aggregates in Shear Flow

    NARCIS (Netherlands)

    Vassileva, Nikolina D.; Ende, van den Dirk; Mugele, Frieder; Mellema, Jorrit

    2006-01-01

    We consider single two-dimensional aggregates, containing glass particles, placed at a water/air interface. We have investigated the critical shear rate for break-up of aggregates with different sizes in a simple shear flow. All aggregates break-up nearly at the same shear rate (1.8 ± 0.2 s-1) indep

  8. Light-particle multiplicity accompanying projectile breakup at 20 MeV/A

    International Nuclear Information System (INIS)

    A large-solid-angle array has been used to determine the multiplicity of Z = 1 and Z = 2 particles accompanying projectile breakup into two fragments each with 5 ≤ Z ≤ 8. The charge balance obtained shows that projectile breakup is not associated with an unusual charge transfer to the target. 13 refs., 1 fig

  9. The breakup of levitating water drops observed with a high speed camera

    Directory of Open Access Journals (Sweden)

    C. Emersic

    2011-10-01

    Full Text Available Collision-induced water drop breakup in a vertical wind tunnel was observed using a high speed camera for interactions between larger drop sizes (up to 7 mm diameter than have previously been experimentally observed. Three distinct collisional breakup types were observed and the drop size distributions from each were analysed for comparison with predictions of fragment distributions from larger drops by two sets of established breakup parameterisations. The observations showed some similarities with both parameterisations but also some marked differences for the breakup types that could be compared, particularly for fragments 1 mm and smaller. Modifications to the parameterisations are suggested and examined. Presented is also currently the largest dataset of bag breakup distributions observed. Differences between this and other experimental research studies and modelling parameterisations, and the associated implications for interpreting results are discussed. Additionally, the stochastic coalescence and breakup equation was solved computationally using a breakup parameterisation, and the evolving drop-size distribution for a range of initial conditions was examined. Initial cloud liquid water content was found to have the greatest influence on the resulting distribution, whereas initial drop number was found to have relatively little influence. This may have implications when considering the effect of aerosol on cloud evolution, raindrop formation and resulting drop size distributions. Calculations presented show that, using an ideal initial cloud drop-size distribution, ~1–3% of the total fragments are contributed from collisional breakup between drops of 4 and 6 mm.

  10. Sub-picosecond pulse break-up in an InGaAsP optical amplifier

    DEFF Research Database (Denmark)

    Romstad, Francis Pascal

    1999-01-01

    broadening and eventual break-up for input pulse energies on the order of picoJoules. This break-up is present in the gain region (6-14 dB), while for absorption (-6 dB) and transparency, pulse narrowing by a factor of two is evidenced. We observe that not only the amplitude is modulated, but also the linear...

  11. Experimental research on breakup of 2D power law liquid film☆

    Institute of Scientific and Technical Information of China (English)

    Lixing Xu; Zhenyan Xia; Mengzheng Zhang; Qing Du; Fuqiang Bai

    2015-01-01

    On account of limited knowledge of the breakup of power law liquid film, the process of its disintegration and atomization was studied by using a planar liquid film. A linear stability analysis was adopted to predict the breakup characteristics of the power law film. The predicting formulas of stripping breakup length and diameter of ligament were put forward presently. Through high-speed photography and laser light sheet illumination, different breakup characteristics of flat power law film under different conditions were derived. The characteristic dimension of breakup regimes were defined and extracted. The effects of several parameters (injection pressure, ambient pressure, nozzle structure and fluid property) on the stripping breakup length and spray angle were investigated. The results revealed that increasing both the velocity of liquid film and the ambient pressure facilitated the breakup of film, reduced the stripping breakup length and enlarged the spray angle in different extents. The comparison between theoretical and experimental results was conducted to validate the feasibility of the linear stability theory.

  12. Drop Breakup in Fixed Bed Flows as Model Stochastic Flow Fields

    Science.gov (United States)

    Shaqfeh, Eric S. G.; Mosler, Alisa B.; Patel, Prateek

    1999-01-01

    We examine drop breakup in a class of stochastic flow fields as a model for the flow through fixed fiber beds and to elucidate the general mechanisms whereby drops breakup in disordered, Lagrangian unsteady flows. Our study consists of two parallel streams of investigation. First, large scale numerical simulations of drop breakup in a class of anisotropic Gaussian fields will be presented. These fields are generated spectrally and have been shown in a previous publication to be exact representations of the flow in a dilute disordered bed of fibers if close interactions between the fibers and the drops are dynamically unimportant. In these simulations the drop shape is represented by second and third order small deformation theories which have been shown to be excellent for the prediction of drop breakup in steady strong flows. We show via these simulations that the mechanisms of drop breakup in these flows are quite different than in steady flows. The predominant mechanism of breakup appears to be very short lived twist breakups. Moreover, the occurrence of breakup events is poorly predicted by either the strength of the local flow in which the drop finds itself at breakup, or the degree of deformation that the drop achieves prior to breakup. It is suggested that a correlation function of both is necessary to be predictive of breakup events. In the second part of our research experiments are presented where the drop deformation and breakup in PDMS/polyisobutylene emulsions is considered. We consider very dilute emulsions such that coalescence is unimportant. The flows considered are simple shear and the flow through fixed fiber beds. Turbidity, small angle light scattering, dichroism and microscopy are used to interrogate the drop deformation process in both flows. It is demonstrated that breakup at very low capillary numbers occurs in both flows but larger drop deformation occurs in the fixed bed flow. Moreover, it is witnessed that breakup in the bed occurs

  13. Numerical simulation of jet breakup behavior by the lattice Boltzmann method

    International Nuclear Information System (INIS)

    In order to understand the jet breakup behavior of the molten core material into coolant during a core disruptive accident (CDA) for a sodium-cooled fast reactor (SFR), we simulated the jet breakup due to the hydrodynamic interaction using the lattice Boltzmann method (LBM). The applicability of the LBM to the jet breakup simulation was validated by comparison with our experimental data. In addition, the influence of several dimensionless numbers such as Weber number and Froude number was examined using the LBM. As a result, we validated applicability of the LBM to the jet breakup simulation, and found that the jet breakup length is independent of Froude number and in good agreement with the Epstein's correlation when the jet interface becomes unstable. (author)

  14. Evidence of the Coulomb force effects in the cross sections of the deuteron-proton breakup at 130 MeV

    CERN Document Server

    Kistryn, S; Bodek, K; Ciepal, I; Deltuva, A; Fonseca, A; Kalantar-Nayestanaki, N; Kis, M; Klos, B; Kozela, A; Mahjour-Shafiei, M; Micherdzinska, A; Sauer, P U; Stephan, E; Sworst, R; Zejma, J; Zipper, W; Kistryn, St.

    2006-01-01

    High precision cross-section data of the deuteron-proton breakup reaction at 130 MeV deuteron energy are compared with the theoretical predictions obtained with a coupled-channel extension of the CD Bonn potential with virtual Delta-isobar excitation, without and with inclusion of the long-range Coulomb force. The Coulomb effect is studied on the basis of the cross-section data set, extended in this work to about 1500 data points by including breakup geometries characterized by small polar angles of the two protons. The experimental data clearly prefer predictions obtained with the Coulomb interaction included. The strongest effects are observed in regions in which the relative energy of the two protons is the smallest.

  15. A PROPOSAL TO MEASURE THE CROSS SECTION OF THE SPACE STAR IN NEUTRON-DEUTERON BREAKUP IN A RECOIL GEOMETRY SETUP

    Energy Technology Data Exchange (ETDEWEB)

    Benjamin J. Crowe III

    2009-09-30

    Nucleon-deuteron (Nd) breakup is an important tool for obtaining a better understanding of three-nucleon (3N) dynamics and for developing meson exchange descriptions of nuclear systems. The kinematics of the nd breakup reaction enable observables to be studied in a variety of exit-channel configurations that show sensitivity to realistic nucleon-nucleon (NN) potential models and three-nucleon force (3NF) models. Rigorous 3N calculations give very good descriptions of most 3N reaction data. However, there are still some serious discrepancies between data and theory. The largest discrepancy observed between theory and data for nd breakup is for the cross section for the space-star configuration. This discrepancy is known as the “Space star Anomaly”. Several experimental groups have obtained results consistent with the “Space Star Anomaly”, but it is important to note that they all used essentially the same experimental setup and so their experimental results are subject to the same systematic errors. We propose to measure the space-star cross-section at the Triangle Universities Nuclear Laboratory (TUNL) using an experimental technique that is significantly different from the one used in previous breakup experiments. This technique has been used by a research group from the University of Bonn to measure the neutron-neutron scattering length. There are three possible scenarios for the outcome of this work: 1) the new data are consistent with previous measurements; 2) the new data are not in agreement with previous measurements, but are in agreement with theory; and 3) the new data are not in agreement with either theory or previous measurements. Any one of the three scenarios will provide valuable insight on the Space Star Anomaly.

  16. A PROPOSAL TO MEASURE THE CROSS SECTION OF THE SPACE STAR IN NEUTRON-DEUTERON BREAKUP IN A RECOIL GEOMETRY SETUP. Final report

    International Nuclear Information System (INIS)

    Nucleon-deuteron (Nd) breakup is an important tool for obtaining a better understanding of three-nucleon (3N) dynamics and for developing meson exchange descriptions of nuclear systems. The kinematics of the nd breakup reaction enable observables to be studied in a variety of exit-channel configurations that show sensitivity to realistic nucleon-nucleon (NN) potential models and three-nucleon force (3NF) models. Rigorous 3N calculations give very good descriptions of most 3N reaction data. However, there are still some serious discrepancies between data and theory. The largest discrepancy observed between theory and data for nd breakup is for the cross section for the space-star configuration. This discrepancy is known as the 'Space Star Anomaly'. Several experimental groups have obtained results consistent with the 'Space Star Anomaly', but it is important to note that they all used essentially the same experimental setup and so their experimental results are subject to the same systematic errors. We propose to measure the space-star cross-section at the Triangle Universities Nuclear Laboratory (TUNL) using an experimental technique that is significantly different from the one used in previous breakup experiments. This technique has been used by a research group from the University of Bonn to measure the neutron-neutron scattering length. There are three possible scenarios for the outcome of this work: (1) the new data are consistent with previous measurements; (2) the new data are not in agreement with previous measurements, but are in agreement with theory; and (3) the new data are not in agreement with either theory or previous measurements. Any one of the three scenarios will provide valuable insight on the Space Star Anomaly.

  17. Equation of state of hot nuclei before break-up

    International Nuclear Information System (INIS)

    Following the method developed by the authors, recently, the equation of state of hot nuclei (238U* in concrete) before break-up was investigated numerically. The isotherms are drawn in the plane of the general pressure P versus volume VRT. They are similar to those of Van der Waals gas. The critical temperature of phase transition should correspond to the isotherm with one truning point only. It turns out that the data of mas yield distribution can be reproduced by many pairs of parameters T and VRT (freeze-out temperature and freezeout volume) varying in certain range. For each isotherm (each T), the data are always best reproduced by the value of VRT located at the maximum general pressure within two phases coexistence region

  18. Inadvertent Earth Reentry Breakup Analysis for the New Horizons Mission

    Science.gov (United States)

    Ling, Lisa M.; Salama, Ahmed; Ivanov, Mark; McRonald, Angus

    2007-01-01

    The New Horizons (NH) spacecraft was launched in January 2006 aboard an Atlas V launch vehicle, in a mission to explore Pluto, its moons, and other bodies in the Kuiper Belt. The NH spacecraft is powered by a Radioisotope Thermoelectric Generator (RTG) which encases multiple General Purpose Heat Source (GPHS) modules. Thus, a pre-launch vehicle breakup analysis for an inadvertent atmospheric reentry in the event of a launch failure was required to assess aerospace nuclear safety and for launch contingency planning. This paper addresses potential accidental Earth reentries analyzed at the Jet Propulsion Laboratory (JPL) which may arise during the ascent to parking orbit, resulting in a suborbital reentry, as well as a departure from parking orbit, resulting in an orbital reentry.

  19. Elastic nucleon-deuteron scattering and breakup with chiral forces

    Directory of Open Access Journals (Sweden)

    Witała Henryk

    2016-01-01

    Full Text Available Results on three-nucleon (3N elastic scattering and breakup below the pion production threshold are discussed. The large discrepancies found between a theory based on numerical solutions of 3N Faddeev equations with standard nucleon-nucleon (NN potentials only and data point to the need for three-nucleon forces (3NF’s. This notion is supported by the fact that another possible reason for the discrepancies in elastic nucleon-deuteron (Nd scattering, relativistic effects, turned out to be small. Results for a new generation of chiral NN forces (up to N4LO together with theoretical truncation errors are shown. They support conclusions obtained with standard NN potentials

  20. AKR breakup and auroral particle acceleration at substorm onset

    Science.gov (United States)

    Morioka, A.; Miyoshi, Y.; Tsuchiya, F.; Misawa, H.; Yumoto, K.; Parks, G. K.; Anderson, R. R.; Menietti, J. D.; Donovan, E. F.; Honary, F.; Spanswick, E.

    2008-09-01

    The dynamical behavior of auroral kilometric radiation (AKR) is investigated in connection with auroral particle acceleration at substorm onsets using high-time-resolution wave spectrograms provided by Polar/PWI electric field observations. AKR develops explosively at altitudes above a preexisting low-altitude AKR source at substorm onsets. This "AKR breakup" suggests an abrupt formation of a new field-aligned acceleration region above the preexisting acceleration region. The formation of the new acceleration region is completed in a very short time (amplitude increases 10,000 times in 30 seconds), suggesting that the explosive development is confined to a localized region. AKR breakups are usually preceded (1-3 minutes) by the appearance and/or gradual enhancement of the low-altitude AKR. This means that the explosive formation of the high-altitude electric field takes place in the course of the growing low-altitude acceleration. The development of the low-altitude acceleration region is thus a necessary condition for the ignition of the high-altitude bursty acceleration. The dH/dt component from a search-coil magnetometer at ground shows that a few minutes prior to substorm onsets, the quasi-DC component begins a negative excursion that is nearly synchronized with the start of the gradual enhancement of the low-altitude AKR, indicating a precursor-like behavior for the substorm. This negative variation of dH/dt suggests an exponentially increasing ionospheric current induced by the upward field-aligned current. At substorm onsets, the decrease in the quasi-DC variation of dH/dt further accelerates, indicating a sudden reinforcement of the field-aligned current.

  1. Influence of Improved Melt Breakup Model in Steam Explosion Simulation

    Energy Technology Data Exchange (ETDEWEB)

    Moriyamaa, Kiyofumi; Pakr, Hyun Sun [Pohang University of Science and Technology, Pohang (Korea, Republic of)

    2015-10-15

    In the steam explosion study, the melt particle size during premixing was given as a constant and a parametric survey was included to cover the bounding (maximum) values for the load or to cover a reasonable range of the uncertainty. For the coolability study, however, an empirical particle size distribution model was introduced into the code since it has a direct impact on the melt cooling behavior. A model for non-local (beyond cell) radiation heat transfer, which can be significant with high temperature melt materials (-3000K) and in relatively long range of time, was also implemented for that purpose. In this work, we revisited the steam explosion analysis with the code with such additional models and examined the influence of those models in the steam explosion simulation. Experiments with alumina and corium (UO{sub 2}- ZrO{sub 2} 80:20wt% mixture) melt, namely KROTOS-44 and FARO-L33 (hereafter K44 and L33) both performed at JRC-Ispra, EU, were referred to. Those data were also used for the validation of the original JASMINE. The simulation of steam explosion experiments with alumina and corium melts was revisited with improved melt breakup model that were introduced for the necessity in relatively long term melt jet breakup and cooling simulation. The model improvement included an empirical melt particle size distribution model and a simplified non-local (beyond cell) radiation heat transfer model. The influence of such models on the steam explosion simulation was not the same for two experiments with different melt materials, and we could not find one consistent set of model parameters with application of the newly introduced models to get satisfactory results on the simulation of both alumina and corium steam explosions.

  2. Effect of Air Entrainment on Breakup of Plunging Liquid Jet into Water Pool

    International Nuclear Information System (INIS)

    The steam explosion intensity is largely dependent upon the degree of volumetric fractions of melt droplets and steam in the fuel-coolant mixture. The rate of melt jet breakup and droplet sizes are, therefore, the key physical parameters in the analysis of FCIs. In a recent OECD/NEA international program SERENA, the areas where research may be needed to reduce the level of uncertainties in the code predictions have been identified. The predicted void fractions in the mixture were generally much higher than experimental data and a deficiency in melt jet breakup modeling would be one of the primary causes. In this paper, an extended study of non-boiling liquid jet breakup from the previous jet breakup experiment is reported with an emphasis on the role of air entrainment by plunging liquid jet into water pool. An improved jet breakup model is also presented with comparison to the experimental data. Non-boiling liquid jet breakup experiment was conducted and the debris size was analyzed with a new jet breakup model with an emphasis on the role of air entrainment. The predicted debris size with consideration of entrained air showed good agreement with the experimental data

  3. Effect of Air Entrainment on Breakup of Plunging Liquid Jet into Water Pool

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyoungtak; Bang, Kwanghyun [Korea Maritime Univ., Busan (Korea, Republic of)

    2013-05-15

    The steam explosion intensity is largely dependent upon the degree of volumetric fractions of melt droplets and steam in the fuel-coolant mixture. The rate of melt jet breakup and droplet sizes are, therefore, the key physical parameters in the analysis of FCIs. In a recent OECD/NEA international program SERENA, the areas where research may be needed to reduce the level of uncertainties in the code predictions have been identified. The predicted void fractions in the mixture were generally much higher than experimental data and a deficiency in melt jet breakup modeling would be one of the primary causes. In this paper, an extended study of non-boiling liquid jet breakup from the previous jet breakup experiment is reported with an emphasis on the role of air entrainment by plunging liquid jet into water pool. An improved jet breakup model is also presented with comparison to the experimental data. Non-boiling liquid jet breakup experiment was conducted and the debris size was analyzed with a new jet breakup model with an emphasis on the role of air entrainment. The predicted debris size with consideration of entrained air showed good agreement with the experimental data.

  4. Influence of melt superheat on breakup process of close-coupled gas atomization

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    In close-coupled gas atomization(CCGA), the influences of melt superheat on breakup process are fundamental to obtain desired or finer powder. Based on a series of Cu atomization experiment under different superheating conditions, the influences of melt superheat on breakup process were studied. Experimental results indicate that as the melt superheat is increased to 150, 200, 250 and 300 K, the mean particle size (D50) decreases consequently to 34.9, 32.3, 30.9 and 19.7 μm. Theoretical analysis reveals that the primary breakup and secondary breakup processes are close coupled, and the melt superheat radically influences the melt properties,and plays a crucial role on governing the filming process of primary breakup and the atomization modes of secondary breakup. There exists a strong nonlinear decrease of contact angle of melt to nozzle orifice wall when the superheat is increased from 250 K to 300 K,leading to a marked fall of the film thickness formed in primary breakup, and D50 of copper powders is therefore sharply reduced.However, the log-normal distribution feature of particle size has not been substantially improved.

  5. 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)

  6. Spatial and temporal patterns in Arctic river ice breakup revealed by automated ice detection from MODIS imagery

    Science.gov (United States)

    Cooley, Sarah; Pavelsky, Tamlin

    2016-04-01

    The annual spring breakup of river ice has important consequences for northern ecosystems and significant economic implications for Arctic industry and transportation. River ice breakup research is restricted by the sparse distribution of hydrological stations in the Arctic, where limited available data suggests a trend towards earlier ice breakup. The specific climatic mechanisms driving this trend, however, are complex and can vary both regionally and within river systems. Consequently, understanding the response of river ice processes to a warming Arctic requires simultaneous examination of spatial and temporal patterns in breakup timing. Here we present an automated algorithm for river ice breakup detection using MODIS satellite imagery that enables identification of spatial and temporal breakup patterns at large scales. We examine breakup timing on the Mackenzie, Lena, Ob' and Yenisey rivers for the period 2000-2014. First, we split each river into 10 km segments. Next, for each day of the breakup season, we classify each river pixel as snow/ice, mixed ice/water or open water based on MODIS reflectance values and remove all cloud-covered segments using the MODIS cloud product. We then define the breakup date as the first day where the segment is 75% open water. Using this method, we are able to determine breakup dates with a mean uncertainty of +/-1.3 days. We find our remotely sensed breakup dates to be highly correlated to ground breakup dates and the timing of peak discharge. All statistically significant temporal trends in breakup timing are negative, indicating an overall shift towards earlier breakup. Considerable variability in the statistical significance and magnitude of trends along each river suggests that different climatic and physiographic drivers are impacting spatial patterns in breakup. Trends detected on the lower Mackenzie corroborate recent studies indicating weakening ice resistance and earlier breakup timing near the Mackenzie Delta. In

  7. Prediction and suppression of beam breakup instability in multicell superconducting cavities

    Science.gov (United States)

    Volkov, V.

    2009-01-01

    Beam breakup instability in superconducting cavities is a serious problem. In this work, a four-cell LEP cavity installed in the KAERI linear accelerator is considered as an example. Dependence of the breakup instability threshold currents on the characteristics of a dipole mode was determined both analytically and numerically. An efficient technique to suppress breakup instability using rf beam focusing within a cavity is suggested. The technique involves applying TE-type monopole higher-order modes and is useful for multicell superconducting cavities with many trapped high-Q dipole modes.

  8. Sensitivity of N/Z ratio in projectile break-up of isobaric systems

    Directory of Open Access Journals (Sweden)

    De Filippo E.

    2016-01-01

    Full Text Available The binary break-up of projectile-like fragments in non central heavy-ion collisions follows different decay patterns, from equilibrated emission towards dynamical (prompt fission. Recently, comparing two systems with different N/Z in the entrance channel, it has been shown that the dynamical emission cross-section is enhanced for the most neutron rich system while the statistical emission cross-section is independent from the isotopic composition. In order to understand this dependence and disentangle it from the initial size of the nuclei, we have studied the two isobaric systems 124Xe+64 Zn and 124Xe+64 Ni at 35 A MeV (InKiIsSy experiment, in comparison with the previous studied reactions (124Sn +64 Ni and 112Sn +58 Ni at the same bombarding energy. We present the first results evidencing a striking similar effect in the dynamical decay as a function of the N/Z of the target for equal size systems.

  9. Investigation of correlations in the breakup of He{sup 8}; Etude des correlations dans la dissociation de l'He{sup 8}

    Energy Technology Data Exchange (ETDEWEB)

    Laurent, B

    2007-11-15

    Correlations in light neutron-rich nuclei are of considerable importance in understanding their structure. In this context the breakup of He{sup 8} into He{sup 6} + 2n has been investigated at 15 MeV/nucleon. The measurements were undertaken using a setup composed of two detector arrays: CHARISSA to detect the charged fragments and DEMON to detect the neutrons. The interpretation of the results was facilitated using a Monte Carlo simulation which was developed to take into account the correlations, the reaction and the experimental setup. Two techniques were used to study the correlations in the breakup of He{sup 8}. The first, intensity interferometry, provides, via the construction of the neutron-neutron correlation function, for a first estimate of the source size and thus the average separation between the neutrons. The second, using Dalitz plots, allows both the neutron-neutron and core-neutron correlations to be probed. Here, sequential decay via the ground state resonance of He{sup 7} and has been found to dominate the dissociation of He{sup 8}. The spatial and temporal characteristics of the breakup of He{sup 8} have thus been deduced and a root-mean-square separation between the two valence neutrons in the continuum states was estimated to be (7.3 {+-} 0.6) fm with a time delay between their emission of (1000 {+-} 300) fm/c. (author)

  10. Asymptotic method for determining the amplitude for three-particle breakup: Neutron-deuteron scattering

    Energy Technology Data Exchange (ETDEWEB)

    Belov, P. A., E-mail: pavelbelov@gmail.com; Yakovlev, S. L., E-mail: yakovlev@cph10.phys.spbu.ru [St. Petersburg State University, Department of Computational Physics (Russian Federation)

    2013-02-15

    The process of neutron-deuteron scattering at energies above the deuteron-breakup threshold is described within the three-body formalism of Faddeev equations. Use is made of the method of solving Faddeev equations in configuration space on the basis of expanding wave-function components in the asymptotic region in bases of eigenfunctions of specially chosen operators. Asymptotically, wave-function components are represented in the form of an expansion in an orthonormalized basis of functions depending on the hyperangle. This basis makes it possible to orthogonalize the contributions of elastic-scattering and breakup channels. The proposed method permits determining scattering and breakup parameters from the asymptotic representation of the wave function without reconstructing it over the entire configuration space. The scattering and breakup amplitudes for states of total spin S = 1/2 and 3/2 were obtained for the s-wave Faddeev equation.

  11. Generalized breakup and coalescence models for population balance modelling of liquid-liquid flows

    CERN Document Server

    Traczyk, Marcin; Thompson, Chris

    2015-01-01

    Population balance framework is a useful tool that can be used to describe size distribution of droplets in a liquid-liquid dispersion. Breakup and coalescence models provide closures for mathematical formulation of the population balance equation (PBE) and are crucial for accu- rate predictions of the mean droplet size in the flow. Number of closures for both breakup and coalescence can be identified in the literature and most of them need an estimation of model parameters that can differ even by several orders of magnitude on a case to case basis. In this paper we review the fundamental assumptions and derivation of breakup and coalescence ker- nels. Subsequently, we rigorously apply two-stage optimization over several independent sets of experiments in order to identify model parameters. Two-stage identification allows us to estab- lish new parametric dependencies valid for experiments that vary over large ranges of important non-dimensional groups. This be adopted for optimization of parameters in breakup...

  12. Coulomb breakup effects on the elastic cross section of $^6$He+$^{209}$Bi scattering near Coulomb barrier energies

    CERN Document Server

    Matsumoto, T; Iseri, Y; Kamimura, M; Ogata, K; Yahiro, M

    2006-01-01

    We accurately analyze the $^6$He+$^{209}$Bi scattering at 19 and 22.5 MeV near the Coulomb barrier energy, using the continuum-discretized coupled-channels method (CDCC) based on the $n$+$n$+$^4$He+$^{209}$Bi four-body model. The three-body breakup continuum of $^6$He is discretized by diagonalizing the internal Hamiltonian of $^6$He in a space spanned by the Gaussian basis functions. The calculated elastic and total reaction cross sections are in good agreement with the experimental data, while the CDCC calculation based on the di-neutron model of $^6$He, i.e., the $^2n$+$^{4}$He+$^{209}$Bi three-body model, does not reproduce the data.

  13. Measuring the area of tear film break-up by image analysis software

    Science.gov (United States)

    Pena-Verdeal, Hugo; García-Resúa, Carlos; Ramos, Lucía.; Mosquera, Antonio; Yebra-Pimentel, Eva; Giráldez, María. Jesús

    2013-11-01

    Tear film breakup time (BUT) test only examines the first break in the tear film, but subsequent tear film events are not monitored. We present a method of measuring the area of breakup after the appearance of the first breakup by using open source software. Furthermore, the speed of the rupture was determined. 84 subjects participated in the study. 2 μl volume of 2% sodium fluorescein was instilled using a micropipette. The subject was seated behind a slit-lamp using a cobalt blue filter together with a Wratten 12 yellow filter. Then, the tear film was recorded by a camera attached to the slit lamp. 4 frames of each video was extracted, the first rupture (BUT_0), breakup after 1 second (BUT_1), rupture after 2 seconds (BUT_2) and breakup before the last blink (BUT_F). Open source software of measurement based on Java (NIH ImageJ) was used to measure the number of pixels in areas of breakup. These areas were divided by the area of exposed cornea to obtain the percentage of ruptures. Instantaneous breakup speed was calculated for second 1 as the difference between BUT_1 - BUT_0, whereas instant speed for second 2 was BUT_2 - BUT_1. Mean area of breakup obtained was: BUT_0 = 0.26%, BUT_1 = 0.48%, BUT_2 = 0.79% and BUT_F = 1.61%. Break speed was 0.22 area/sec for second 1 and 0.31 area/sec for second 2, showing a statistical difference between them (p = 0.007). Post BUT analysis may be easily monitoring with the aid of this software.

  14. A Genesis breakup and burnup analysis in off-nominal Earth return and atmospheric entry

    Science.gov (United States)

    Salama, Ahmed; Ling, Lisa; McRonald, Angus

    2005-01-01

    The Genesis project conducted a detailed breakup/burnup analysis before the Earth return to determine if any spacecraft component could survive and reach the ground intact in case of an off-nominal entry. In addition, an independent JPL team was chartered with the responsibility of analyzing several definitive breakup scenarios to verify the official project analysis. This paper presents the analysis and results of this independent team.

  15. Drag-induced breakup mechanism for droplet generation in dripping within flow focusing microfluidics

    Institute of Scientific and Technical Information of China (English)

    Ping Wu; Zhaofeng Luo; Zhifeng Liu; Zida Li; Chi Chen; Lili Feng; Liqun He

    2015-01-01

    Based on viscous drag-induced breakup mechanism, a simple model was proposed to predict the dripping drop-let size as a function of controllable parameters in flow focusing micro devices. The size of thread before breakup was also investigated through laminar flow theory. Experiments and numerical simulations by VOF are carried out simultaneously to validate the theoretical analysis, showing that droplet size decreases rapidly with the in-crease of the flow rate ratio and capil ary number.

  16. Sub-picosecond pulse break-up in an InGaAsP optical amplifier

    DEFF Research Database (Denmark)

    Romstad, Francis Pascal

    broadening and eventual break-up for input pulse energies on the order of picoJoules. This break-up is present in the gain region (6-14 dB), while for absorption (-6 dB9 and transparency, pulse narrowing by a factor of two is evidenced. We observe that not only the amplitude is modulated, but also the linear...

  17. Panjal Paleomagnetism: Implications for Early Permian Gondwana break-up

    Science.gov (United States)

    Stojanovic, D.; Aitchison, J.; Ali, J. R.; Ahmad, T.; Ahmad Dar, R.; Agarwal, A.; Roeder, T.

    2013-12-01

    The mid-Early Permian represents an important phase in Pangaea's development marking the time when the >13,000 km-long string of terranes that are collectively known as 'Cimmeria' separated from Gondwana's Tethyan margin (northern Africa-NE Arabia-northern India-NW and northern Australia). The ~289 Ma Panjal Traps of NW India (Kashmir) are one of a number of mafic suites (Abor, Sikkim etc.) that were erupted onto the Indian block possibly during the separation of the Lhasa/SE Qiangtang block. Herein, we report data from the first modern paleomagnetic study of the unit. Results from four quarry sections (15 individual cooling units) from a locality close to Srinagar together form a tectonically coherent sequence spanning 2-3 km of stratigraphy. The derived direction and paleopole yield key new information concerning (1) the Early Permian location of India, and by inference that of central Gondwana, and (2) inform debates related to Cimmeria's breakup from eastern Gondwana. Moreover, they provide a new independent control for assessing NW Greater India's extent prior to its collision with Asia and the amount of vertical-axis rotation this sector of the Himalayan range experienced in the mid to late Cenozoic.

  18. Cheating, breakup, and divorce: is Facebook use to blame?

    Science.gov (United States)

    Clayton, Russell B; Nagurney, Alexander; Smith, Jessica R

    2013-10-01

    The purpose of the present study was to investigate the relationship between using the social networking site known as Facebook and negative interpersonal relationship outcomes. A survey of 205 Facebook users aged 18-82 was conducted using a 16-question online survey to examine whether high levels of Facebook use predicted negative relationship outcomes (breakup/divorce, emotional cheating, and physical cheating). It was hypothesized that those with higher levels of Facebook use would demonstrate more negative relationship outcomes than those with lower use. The study then examined whether these relationships were mediated by Facebook-related conflict. Furthermore, the researchers examined length of relationship as a moderator variable in the aforementioned model. The results indicate that a high level of Facebook usage is associated with negative relationship outcomes, and that these relationships are indeed mediated by Facebook-related conflict. This series of relationships only holds for those who are, or have been, in relatively newer relationships of 3 years or less. The current study adds to the growing body of literature investigating Internet use and relationship outcomes, and may be a precursor to further research investigating whether Facebook use attributes to the divorce rate, emotional cheating, and physical cheating.

  19. Sequential three-body breakup of a CO 2 + beam

    Science.gov (United States)

    Rajput, Jyoti; Ablikim, U.; Zohrabi, M.; Jochim, Bethany; Berry, Ben; Carnes, K. D.; Esry, B. D.; Ben-Itzhak, I.

    2016-05-01

    The dissociative double ionization of a CO2+beam leading to the three-body fragmentation channel C+ + O+ + O+ can have its origin in either a sequential or concerted process. In case of the sequential mechanism, the first step is a two-body breakup into CO2+ + O+, followed by a second step wherein CO2+ further fragments into C+ + O+. The rotation of the CO2+ formed during the first step has been used to discriminate between the sequential and non-sequential mechanisms in experiments which employ multi-coincidence momentum imaging techniques for detecting recoil fragments. We propose a novel way to look at this discriminating feature in terms of the angle of rotation of the CO2+ intermediate. We will also discuss the implications on the measured momentum distribution of detecting indistinguishable fragments in a coincidence measurement. This work was supported by the Chemical Sciences, Geosciences, and Biosciences Division, Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy. BJ was also supported by DOE-SCGF (DE-AC05-06OR23100).

  20. Aerosol cluster impact and break-up : model and implementation.

    Energy Technology Data Exchange (ETDEWEB)

    Lechman, Jeremy B.

    2010-10-01

    In this report a model for simulating aerosol cluster impact with rigid walls is presented. The model is based on JKR adhesion theory and is implemented as an enhancement to the granular (DEM) package within the LAMMPS code. The theory behind the model is outlined and preliminary results are shown. Modeling the interactions of small particles is relevant to a number of applications (e.g., soils, powders, colloidal suspensions, etc.). Modeling the behavior of aerosol particles during agglomeration and cluster dynamics upon impact with a wall is of particular interest. In this report we describe preliminary efforts to develop and implement physical models for aerosol particle interactions. Future work will consist of deploying these models to simulate aerosol cluster behavior upon impact with a rigid wall for the purpose of developing relationships for impact speed and probability of stick/bounce/break-up as well as to assess the distribution of cluster sizes if break-up occurs. These relationships will be developed consistent with the need for inputs into system-level codes. Section 2 gives background and details on the physical model as well as implementations issues. Section 3 presents some preliminary results which lead to discussion in Section 4 of future plans.

  1. Asteroid breakup linked to the Great Ordovician Biodiversification Event

    Science.gov (United States)

    Schmitz, Birger; Harper, David A. T.; Peucker-Ehrenbrink, Bernhard; Stouge, Svend; Alwmark, Carl; Cronholm, Anders; Bergström, Stig M.; Tassinari, Mario; Xiaofeng, Wang

    2008-01-01

    The rise and diversification of shelled invertebrate life in the early Phanerozoic eon occurred in two major stages. During the first stage (termed as the Cambrian explosion), a large number of new phyla appeared over a short time interval ~540Myrago. Biodiversity at the family, genus and species level, however, remained low until the second stage marked by the Great Ordovician Biodiversification Event in the Middle Ordovician period. Although this event represents the most intense phase of species radiation during the Palaeozoic era and led to irreversible changes in the biological make-up of Earth's seafloors, the causes of this event remain elusive. Here, we show that the onset of the major phase of biodiversification ~470Myrago coincides with the disruption in the asteroid belt of the L-chondrite parent body-the largest documented asteroid breakup event during the past few billion years. The precise coincidence between these two events is established by bed-by-bed records of extraterrestrial chromite, osmium isotopes and invertebrate fossils in Middle Ordovician strata in Baltoscandia and China. We argue that frequent impacts on Earth of kilometre-sized asteroids-supported by abundant Middle Ordovician fossil meteorites and impact craters-accelerated the biodiversification process.

  2. Deformation, wave phenomena, and breakup outcomes of round nonturbulent liquid jets in uniform gaseous crossflow

    Science.gov (United States)

    Ng, Chee-Loon

    Scope and method of study. An experimental and computational research is performed to study the deformation and breakup of round nonturbulent liquid jets in uniform gaseous crossflow. Pulsed photography and shadow graphy in conjunction with high-speed imaging were used to study the wave phenomena and the droplets properties/transport dynamics of a nonturbulent liquid jet injected into a uniform crossflow within the bag breakup regime. The computational study extended the previous two-dimensional study by adding the third dimension, allowing the wave properties to be modeled. The computational simulation employed the Volume of Fluid (VOF) formulation of FLUENT, and was run on a 3-processors parallel Linux cluster and P4 desktops. The validated, time-accurate, CFD simulation analyzes the surface properties of the liquid jets within the column, bag, and shear breakup regimes by considering the effects of surface tension, liquid viscosity, and crossflow Weber number at large liquid/gas density ratios (>500) and small Ohnesorge numbers (liquid jet are attributed to Rayleigh-Taylor instabilities and the nodes layout per bag affected the breakup mechanisms of the bags. Three distinctive sizes of droplets were produced in the bag breakup regime. The size of bag-droplets normalized by the nozzle exit diameter was constant. The different trajectories for bag- and node-droplets suggested that separation of bag- and node-droplets is possible. The computational results included jet deformations, jet cross-sectional area, jet velocity, wake velocity defect, wake width, and wavelengths of column and surface waves. Present computational results yielded a similarity solution for the inner wake region. In bag breakup, the lower pressure along the sides of the jet pulled the liquid away from both the upwind and downwind surfaces of the liquid cross-section. In shear breakup, the flattened upwind surface pushed the liquid towards the two sides of the jet. In bag breakup, the flow

  3. Effective radii of deuteron induced reactions

    CERN Document Server

    Hashimoto, Shintaro; Ogata, Kazuyuki; Minomo, Kosho; Chiba, Satoshi

    2011-01-01

    The continuum-discretized coupled-channels method (CDCC) for exclusive reactions and the eikonal reaction theory (ERT) as an extension of CDCC to inclusive reactions are applied to deuteron induced reactions. The CDCC result reproduces experimental data on the reaction cross section for $d+^{58}$Ni scattering at 200 MeV/nucleon and ERT does data on the neutron-stripping cross section for inclusive $^7$Li$(d,n)$ reaction at 40 MeV. For deuteron induced reactions at 200 MeV/nucleon, target-dependence of the reaction, elastic-breakup, nucleon-stripping, nucleon-removal, complete- and incomplete-fusion cross sections is clearly explained by simple formulae. Accuracy of the Glauber model is also investigated.

  4. Numerical and experimental study of liquid breakup process in solid rocket motor nozzle

    Science.gov (United States)

    Yen, Yi-Hsin

    Rocket propulsion is an important travel method for space exploration and national defense, rockets needs to be able to withstand wide range of operation environment and also stable and precise enough to carry sophisticated payload into orbit, those engineering requirement makes rocket becomes one of the state of the art industry. The rocket family have been classified into two major group of liquid and solid rocket based on the fuel phase of liquid or solid state. The solid rocket has the advantages of simple working mechanism, less maintenance and preparing procedure and higher storage safety, those characters of solid rocket make it becomes popular in aerospace industry. Aluminum based propellant is widely used in solid rocket motor (SRM) industry due to its avalibility, combusion performance and economical fuel option, however after aluminum react with oxidant of amonimum perchrate (AP), it will generate liquid phase alumina (Al2O3) as product in high temperature (2,700˜3,000 K) combustion chamber enviornment. The liquid phase alumina particles aggromorate inside combustion chamber into larger particle which becomes major erosion calprit on inner nozzle wall while alumina aggromorates impinge on the nozzle wall surface. The erosion mechanism result nozzle throat material removal, increase the performance optimized throat diameter and reduce nozzle exit to throat area ratio which leads to the reduction of exhaust gas velocity, Mach number and lower the propulsion thrust force. The approach to avoid particle erosion phenomenon taking place in SRM's nozzle is to reduce the alumina particle size inside combustion chamber which could be done by further breakup of the alumina droplet size in SRM's combustion chamber. The study of liquid breakup mechanism is an important means to smaller combustion chamber alumina droplet size and mitigate the erosion tack place on rocket nozzle region. In this study, a straight two phase air-water flow channel experiment is set up

  5. Dynamical diagnosis of the breakup of the stratospheric polar vortex in the Northern Hemisphere

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The research on climate change in polar regions, especially on the role of polar in the global climate system, has gain unprecedented level of interest. It has been the key scientific issue of the International Polar Year program (IPY, 2007―2008). In this paper, we dealt with the debate upon the breakup time of the stratospheric polar vortex in boreal spring. An observational study of the relation between stratospheric polar vortex breakup and the extra-tropical circulation was performed. The mean breakup date―when the winter westerly at the core of polar jet turns to summer easterly―is about April 10. The breakup time has large interannual variation with a time span of about 2 months. It also has a long-term trend with the 1990s and 2000s witnessing more and more late breakups of polar vortex. Composite of wind speed at the core of polar jet for the extremely early and late breakup years shows that late years have two periods of westerly weakening while early breakup years have only one. The first weakening in the late years happens in middle January with wind speed dropping sharply from more than 40 m s-1 to about 15 m s-1. This is accompanied with anomalous activities of planetary waves in both stratosphere and troposphere; while the second weakening in the late breaking years is mainly the results of diabatic heating with very weak wave activities. In early breakup years, the transition from westerly to easterly is rapid with wind speed dropping from more than 30 m s-1 to less than -10 m s-1 within a month. This evolution is associated with a strong bidirectional dynamical coupling of the stratosphere and troposphere. The circulation anomalies at low troposphere are also analyzed in the extremely early and late breakup years. It shows that there are significant differences between the two kinds of extreme years in the geopotential height and temperature composite analysis, indicating the dynamical coupling of stratosphere and troposphere with the

  6. Three-cluster breakup in deuteron-deuteron collisions: single-scattering approximation

    CERN Document Server

    Deltuva, A

    2016-01-01

    We present results for the three-cluster breakup in deuteron-deuteron collisions at 130 and 270 MeV deuteron beam energy. The breakup amplitude is calculated using the first term in the Neumann series expansion of the corresponding exact four-nucleon equations. In analogy with nucleon-deuteron breakup where an equivalent approximation is compared with exact calculations, we expect this single-scattering approximation to provide a rough estimation of three-body breakup observables in quasifree configurations. We predict the nucleon-deuteron and deuteron-deuteron three-cluster breakup cross sections to be of a comparable size and thereby question the reliability of the recent experimental data [A. Ramazani-Moghaddam-Arani, Ph.D. thesis, University of Groningen, 2009; A. Ramazani-Moghaddam-Arani et al., EPJ Web of Conferences 3, 04012 (2010)] that is smaller by about three orders of magnitude. We also show that an equivalent single-scattering approximation provides a reasonable description of deuteron-deuteron e...

  7. Effects of the geometric orientations of the nozzle exit on the breakup of free liquid jet

    Energy Technology Data Exchange (ETDEWEB)

    Lad, V. N.; Murthy, Z. V. P. [Sardar Vallabhbhai National Institute of Technology, Gujarat (India)

    2016-04-15

    Free liquid jets are produced through various geometric orientations of the nozzle exit. The breakup lengths of liquid jets under various geometric orientations of the nozzle exit were studied. Images of jets were captured using a high-speed camera with a maximum frame rate of 1000 frames per second and were analyzed to determine the dynamics between jets and breakup lengths. The breakup length of jets changes with the cut angle of the nozzle exit. In addition, adding polymer reduces the effect of the cut angle of the nozzle exit on the breakup length for an entire range of velocities. The effect of the cut angle on breakup length is predominant for aqueous solutions with surfactants. This work provides motivation for further computational research to study jet dynamics in a partially covered nozzle exit, such as the case in which the boundary conditions near the nozzle opening is more complex with the cut angle and its vertex position, which directly reflects liquid jet dynamics.

  8. Breakup characteristics of power-law liquid sheets formed by two impinging jets

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Fuqiang; Diao, Hai; Chang, Qing; Wang, Endong; Du, Qing [State Key Laboratory of Engines, Tianjin University, Tianjin, 300072, People’s Republic of China (China); Zhang, Mengzheng, E-mail: duqing@tju.edu.cn [Xi’an Aerospace Propulsion Institute, Xi’an, 710100, People’s Republic of China (China)

    2014-10-01

    The breakup characteristics of the shear-thinning power-law liquid sheets formed by two impinging jets have been investigated with the shadowgraph technique. This paper focuses on the effects of spray parameters (jet velocity), physical parameters (viscosity) and geometry parameters (impinging angle and nozzle cross-sectional shape) on the breakup behaviors of liquid sheets. The breakup mode, sheet length and expansion angle of the sheet are extracted from the spray images obtained by a high speed camera. Impinging angle and Weber number play the similar roles in promoting the breakup of liquid sheets. With the increase of jet velocity, five different breakup modes are observed and the expansion angle increases consistently after the closed-rim mode while the sheet length first increases and then decreases. But there exists a concave consisting of a fierce drop and a second rising process on the sheet length curve for the fluid with smaller viscosity. Different nozzle cross-sectional shapes emphasize significant effects on the sheet length and expansion angle of liquid sheets. At a fixed Weber number, the liquid sheet with greater viscosity has a greater sheet length and a smaller expansion angle due to the damping effect of viscosity. (papers)

  9. Mechanism of Water Droplet Breakup Near the Leading Edge of an Airfoil

    Science.gov (United States)

    Vargas, Mario; Sor, Suthyvann; Magarino, Adelaida, Garcia

    2012-01-01

    This work presents results of an experimental study on droplet deformation and breakup near the leading edge of an airfoil. The experiment was conducted in the rotating rig test cell at the Instituto Nacional de Tecnica Aeroespacial (INTA) in Madrid, Spain. The airfoil model was placed at the end of the rotating arm and a monosize droplet generator produced droplets that fell from above, perpendicular to the path of the airfoil. The interaction between the droplets and the airfoil was captured with high speed imaging and allowed observation of droplet deformation and breakup as the droplet approached the airfoil near the stagnation line. Image processing software was used to measure the position of the droplet centroid, equivalent diameter, perimeter, area, and the major and minor axes of an ellipse superimposed over the deforming droplet. The horizontal and vertical displacement of each droplet against time was also measured, and the velocity, acceleration, Weber number, Bond number, Reynolds number, and the drag coefficients were calculated along the path of the droplet to the beginning of breakup. Droplet deformation is defined and studied against main parameters. The high speed imaging allowed observation of the actual mechanism of breakup and identification of the sequence of configurations from the initiation of the breakup to the disintegration of the droplet. Results and comparisons are presented for droplets of diameters in the range of 500 to 1800 microns, and airfoil velocities of 70 and 90 m/sec.

  10. Assessment of the Breakup of the Antarctic Polar Vortex in Two New Chemistry-Climate Models

    Science.gov (United States)

    Hurwitz, M. M.; Newman, P. A.; Oman, L. D.; Li, F.; Morgenstern, O.; Braesicke, P.; Pyle, J. A.

    2010-01-01

    Successful simulation of the breakup of the Antarctic polar vortex depends on the representation of tropospheric stationary waves at Southern Hemisphere middle latitudes. This paper assesses the vortex breakup in two new chemistry-climate models (CCMs). The stratospheric version of the UK Chemistry and Aerosols model is able to reproduce the observed timing of the vortex breakup. Version 2 of the Goddard Earth Observing System (GEOS V2) model is typical of CCMs in that the Antarctic polar vortex breaks up too late; at 10 hPa, the mean transition to easterlies at 60 S is delayed by 12-13 days as compared with the ERA-40 and National Centers for Environmental Prediction reanalyses. The two models' skill in simulating planetary wave driving during the October-November period accounts for differences in their simulation of the vortex breakup, with GEOS V2 unable to simulate the magnitude and tilt of geopotential height anomalies in the troposphere and thus underestimating the wave driving. In the GEOS V2 CCM the delayed breakup of the Antarctic vortex biases polar temperatures and trace gas distributions in the upper stratosphere in November and December.

  11. Development of the VESUVIUS module. Molten jet breakup modeling and model verification

    Energy Technology Data Exchange (ETDEWEB)

    Vierow, K. [Nuclear Power Engineering Corp., Tokyo (Japan); Nagano, Katsuhiro; Araki, Kazuhiro

    1998-01-01

    With the in-vessel vapor explosion issue ({alpha}-mode failure) now considered to pose an acceptably small risk to the safety of a light water reactor, ex-vessel vapor explosions are being given considerable attention. Attempts are being made to analytically model breakup of continuous-phase jets, however uncertainty exists regarding the basic phenomena. In addition, the conditions upon reactor vessel failure, which determine the starting point of the ex-vessel vapor explosion process, are difficult to quantify. Herein, molten jet ejection from the reactor pressure vessel is characterized. Next, the expected mode of jet breakup is determined and the current state of analytical modeling is reviewed. A jet breakup model for ex-vessel scenarios, with the primary breakup mechanism being the Kelvin-Helmholtz instability, is described. The model has been incorporated into the VESUVIUS module and comparisons of VESUVIUS calculations against FARO L-06 experimental data show differences, particularly in the pressure curve and amount of jet breakup. The need for additional development to resolve these differences is discussed. (author)

  12. Capillary thinning and breakup of saliva threads and rheological aging of mucin solutions

    Science.gov (United States)

    Wagner, Caroline; Bourouiba, Lydia; McKinley, Gareth

    2014-11-01

    The elasticity of saliva, which is essential for many of its primary functions such as lubrication, arises largely as a result of the presence of MUC5B mucins. These are large glycoproteins composed of numerous repeated polymeric subunits forming a weakly crosslinked network. It has been noted for nearly a century that once removed from the mouth, saliva quickly loses its elasticity, which can be quantified by a decrease in its capillary breakup time. We model saliva as a dilute finitely extensible nonlinear elastic (FENE-P) fluid with polymer chains composed of dispersed Hookean dumbbells of maximum extensibility b related to the number of MUC5B subunits. We show that under conditions of simple elongational flow, an analytic prediction of the time evolution of the radius and the filament breakup time can be derived. Furthermore, our model shows that decreasing the maximum extensibility b leads to a decrease in the breakup time, which suggests that the aging process of saliva outside the mouth involves a shortening of the MUC5B mucin chains into smaller groupings. Finally, we compare the analytic breakup times from the model with experimental results obtained using a capillary breakup extensional rheometer and human whole saliva.

  13. Three-cluster breakup in deuteron-deuteron collisions: Single-scattering approximation

    Science.gov (United States)

    Deltuva, A.; Fonseca, A. C.

    2016-04-01

    We present results for the three-cluster breakup in deuteron-deuteron collisions at 130 and 270 MeV deuteron beam energy. The breakup amplitude is calculated using the first term in the Neumann series expansion of the corresponding exact four-nucleon equations. In analogy with nucleon-deuteron breakup where an equivalent approximation is compared with exact calculations, we expect this single-scattering approximation to provide a rough estimation of three-body breakup observables in quasifree configurations. We predict the nucleon-deuteron and deuteron-deuteron three-cluster breakup cross sections to be of a comparable size and thereby question the reliability of the recent experimental data [A. Ramazani-Moghaddam-Arani, Ph.D. thesis, University of Groningen, 2009; A. Ramazani-Moghaddam-Arani et al., EPJ Web Conf. 3, 04012 (2010), 10.1051/epjconf/20100304012], which are smaller by about three orders of magnitude. We also show that an equivalent single-scattering approximation provides a reasonable description of deuteron-deuteron elastic scattering at forward-scattering angles.

  14. Physics-Based Modeling of Meteor Entry and Breakup

    Science.gov (United States)

    Prabhu, Dinesh K.; Agrawal, Parul; Allen, Gary A., Jr.; Bauschlicher, Charles W., Jr.; Brandis, Aaron M.; Chen, Yih-Kang; Jaffe, Richard L.; Palmer, Grant E.; Saunders, David A.; Stern, Eric C.; Tauber, Michael E.; Venkatapathy, Ethiraj

    2015-01-01

    A new research effort at NASA Ames Research Center has been initiated in Planetary Defense, which integrates the disciplines of planetary science, atmospheric entry physics, and physics-based risk assessment. This paper describes work within the new program and is focused on meteor entry and breakup.Over the last six decades significant effort was expended in the US and in Europe to understand meteor entry including ablation, fragmentation and airburst (if any) for various types of meteors ranging from stony to iron spectral types. These efforts have produced primarily empirical mathematical models based on observations. Weaknesses of these models, apart from their empiricism, are reliance on idealized shapes (spheres, cylinders, etc.) and simplified models for thermal response of meteoritic materials to aerodynamic and radiative heating. Furthermore, the fragmentation and energy release of meteors (airburst) is poorly understood.On the other hand, flight of human-made atmospheric entry capsules is well understood. The capsules and their requisite heatshields are designed and margined to survive entry. However, the highest speed Earth entry for capsules is 13 kms (Stardust). Furthermore, Earth entry capsules have never exceeded diameters of 5 m, nor have their peak aerothermal environments exceeded 0.3 atm and 1 kW/sq cm. The aims of the current work are: (i) to define the aerothermal environments for objects with entry velocities from 13 to 20 kms; (ii) to explore various hypotheses of fragmentation and airburst of stony meteors in the near term; (iii) to explore the possibility of performing relevant ground-based tests to verify candidate hypotheses; and (iv) to quantify the energy released in airbursts. The results of the new simulations will be used to anchor said risk assessment analyses. With these aims in mind, state-of-the-art entry capsule design tools are being extended for meteor entries. We describe: (i) applications of current simulation tools to

  15. Effects of thermal quenching on the breakup of pyroclasts

    Science.gov (United States)

    Patel, A.; Manga, M.; Carey, R. J.; Degruyter, W.; Dufek, J.

    2012-12-01

    wet density increased 0 to 2.5 %, as measured after 5 minutes immersion in water. Overall we see modest differences between quenched pumice and regular pumice in breakup, abrasion, mass, and effective wet density. Experimental results suggest that quenching may damage small parts of a clast but tends not to cause cracks that propagate easily through the clast. XRT and SEM imaging confirms that quenching only damages small external parts. This is in stark contrast to non-vesicular glass that develops large cracks on quenching.

  16. Trojan Horse particle invariance in fusion reactions

    Directory of Open Access Journals (Sweden)

    Pizzone R.G.

    2015-01-01

    Full Text Available Trojan Horse method plays an important part for the measurement of several charged particle induced reactions cross sections of astrophysical interest. In order to better understand its cornerstones and the related applications to different astrophysical scenarios several tests were performed to verify all its properties and the possible future perspectives. The Trojan Horse nucleus invariance for the binary reactions d(d,pt, 6,7Li(p,α3,4He was therefore tested using the appropriate quasi free break- ups, respectively. In the first cases results from 6Li and 3He break up were used, while for the lithium fusion reactions break-ups of 2H and 3He were compared. The astrophysical S(E-factors for the different processes were then extracted in the framework of the PlaneWave Approximation applied to the different break-up schemes. The obtained results are compared with direct data as well as with previous indirect investigations. The very good agreement between data coming from different break-up schemes confirms the applicability of the plane wave approximation and suggests the independence of binary indirect cross section on the chosen Trojan Horse nucleus also for the present cases. Moreover the astrophysical implications of the results will also be discussed in details.

  17. Trojan Horse particle invariance in fusion reactions

    Science.gov (United States)

    Pizzone, R. G.; Spitaleril, C.; Bertulani, C.; Mukhamedzhanov, A.; Blokhintsev, L.; La Cognata, M.; Lamia, L.; Spartá, R.; Tumino, A.

    2015-01-01

    Trojan Horse method plays an important part for the measurement of several charged particle induced reactions cross sections of astrophysical interest. In order to better understand its cornerstones and the related applications to different astrophysical scenarios several tests were performed to verify all its properties and the possible future perspectives. The Trojan Horse nucleus invariance for the binary reactions d(d,p)t, 6,7Li(p,α)3,4He was therefore tested using the appropriate quasi free break- ups, respectively. In the first cases results from 6Li and 3He break up were used, while for the lithium fusion reactions break-ups of 2H and 3He were compared. The astrophysical S(E)-factors for the different processes were then extracted in the framework of the PlaneWave Approximation applied to the different break-up schemes. The obtained results are compared with direct data as well as with previous indirect investigations. The very good agreement between data coming from different break-up schemes confirms the applicability of the plane wave approximation and suggests the independence of binary indirect cross section on the chosen Trojan Horse nucleus also for the present cases. Moreover the astrophysical implications of the results will also be discussed in details.

  18. Simultaneous visual acquisition of melt jet breakup in water by high speed videography and radiography

    International Nuclear Information System (INIS)

    Motivated to understand molten corium jet falling in a water pool and fragmenting into droplets in the coolant during a hypothetical severe accident in a light water reactor (LWR), this paper presents insights on the dynamics of a coherent molten material jet and its breakup as a function of molten jet initial conditions (jet initial velocity, diameter, etc.) and material thermo-physical properties, with several corium simulant materials from low-melting temperature metallic melt (woods metal) to medium-melting temperature binary oxide melts (e.g., WO3-Bi2O3, WO3-ZrO2). A visualization system of Simultaneous High-speed Acquisition of Radiography and Photography (SHARP) is employed to quantify the characteristics of the melt jet breakup in a water pool. The experiment features well-controlled conditions and small-scale jets which can be visualized by X-ray, and therefore enables a better scrutiny of the jet breakup. (author)

  19. Drop deformation and breakup in a partially filled horizontal rotating cylinder

    Science.gov (United States)

    White, Andrew; Pereira, Caroline; Hyacinthe, Hyaquino; Ward, Thomas

    2014-11-01

    Drop deformation and breakup due to shear flow has been studied extensively in Couette devices as well as in gravity-driven flows. In these cases shear is generated either by the moving wall or the drop's motion. For such flows the drop shape remains unperturbed at low capillary number (Ca), deforms at moderate Ca , and can experience breakup as Ca --> 1 and larger. Here single drops of NaOH(aq) will be placed in a horizontal cylindrical rotating tank partially filled with vegetable oil resulting in 10-2 saponification, can yield lower minimum surface tensions and faster adsorption than non-reactive surfactant systems. Oil films between the wall and drop as well as drop shape will be observed as rotation rates and NaOH(aq) concentration are varied. Results will be presented in the context of previous work on bubble and drop shapes and breakup. NSF CBET #1262718.

  20. Numerical simulation of liquid jet breakup using smoothed particle hydrodynamics (SPH)

    CERN Document Server

    Pourabdian, Majid; Morad, Mohammad Reza

    2016-01-01

    In this paper, breakup of liquid jet is simulated using smoothed particle hydrodynamics (SPH) which is a meshless Lagrangian numerical method. For this aim, flow governing equations are discretized based on SPH method. In this paper, SPHysics open source code has been utilized for numerical solutions. Therefore, the mentioned code has been developed by adding the surface tension effects. The proposed method is then validated using dam break with obstacle problem. Finally, simulation of twodimensional liquid jet flow is carried out and its breakup behavior considering one-phase flow is investigated. Length of liquid breakup in Rayleigh regime is calculated for various flow conditions such as different Reynolds and Weber numbers and the results are validated by an experimental correlation. The whole numerical solutions are accomplished for both Wendland and cubic spline kernel functions and Wendland kernel function gave more accurate results. The results are compared to MPS method for inviscid liquid as well. T...

  1. Research on the Rebound and Breakup of the Droplet after Impacting on the Superhydrophobic Wall

    Science.gov (United States)

    Liu, D. W.; Ning, Z.; Lü, M.; Yan, K.; Sun, C. H.

    The surface hydrophilicity affects the movement of the droplet intensively when the droplet impacting on a wall, In this paper, the motion of the droplet after impacting on the superhydrophobic wall were researched by using the combined Level Set-VOF method for gas-liquid interface tracking. The results show that, the droplet would rebound after impacting on the superhydrophobic wall when the velocity is small: the droplet would breakup after when the velocity is larger; the droplet would breakup during spreading when the initial diameter is larger and less surface tension: impact angle affect the movement of the chop-let intensively after impacting on the wall. At the same time, this paper obtains critical conditions of rebound an breakup after droplet impacts on the superliydrophbic wall by vertical or inclined angle through numerical simulation in a certain range of condition.

  2. Droplet Deformation Prediction With the Droplet Deformation and Breakup Model (DDB)

    Science.gov (United States)

    Vargas, Mario

    2012-01-01

    The Droplet Deformation and Breakup Model was used to predict deformation of droplets approaching the leading edge stagnation line of an airfoil. The quasi-steady model was solved for each position along the droplet path. A program was developed to solve the non-linear, second order, ordinary differential equation that governs the model. A fourth order Runge-Kutta method was used to solve the equation. Experimental slip velocities from droplet breakup studies were used as input to the model which required slip velocity along the particle path. The center of mass displacement predictions were compared to the experimental measurements from the droplet breakup studies for droplets with radii in the range of 200 to 700 mm approaching the airfoil at 50 and 90 m/sec. The model predictions were good for the displacement of the center of mass for small and medium sized droplets. For larger droplets the model predictions did not agree with the experimental results.

  3. Eikonal reaction theory

    CERN Document Server

    Yahiro, Masanobu; Minomo, Kosho

    2011-01-01

    We present an accurate method of treating the one-neutron removal reaction at intermediate incident energies induced by both nuclear and Coulomb interactions. In the method, the nuclear and Coulomb breakup processes are consistently treated by the method of continuum discretized coupled channels without making the adiabatic approximation to the Coulomb interaction, so that the removal cross section calculated never diverges. This method is applied to recently measured one-neutron removal cross section for $^{31}$Ne+$^{12}$C scattering at 230 MeV/nucleon and $^{31}$Ne+$^{208}$Pb scattering at 234 MeV/nucleon. The spectroscopic factor and the asymptotic normalization coefficient of the last neutron in $^{31}$Ne are evaluated.

  4. On jet impingement and thin film breakup on a horizontal superhydrophobic surface

    Science.gov (United States)

    Prince, Joseph F.; Maynes, Daniel; Crockett, Julie

    2015-11-01

    When a vertical laminar jet impinges on a horizontal surface, it will spread out in a thin film. If the surface is hydrophobic and a downstream depth is not maintained, the film will radially expand until it breaks up into filaments or droplets. We present the first analysis and model that describes the location of this transition for both isotropic and anisotropic structured superhydrophobic (SH) surfaces. All surfaces explored are hydrophobic or SH, where the SH surfaces exhibit an apparent slip at the plane of the surface due to a shear free condition above the air filled cavities between the structures. The influence of apparent slip on the entire flow field is significant and yields behavior that deviates notably from classical behavior for a smooth hydrophilic surface where a hydraulic jump would form. Instead, break up into droplets occurs where the jet's outward radial momentum is balanced by the inward surface tension force of the advancing film. For hydrophobic surfaces, or SH surfaces with random micropatterning, the apparent slip on the surface is uniform in all directions and droplet breakup occurs in a circular pattern. When alternating rib/cavity microstructures are used to create the SH surface, the apparent slip varies as a function of the azimuthal coordinate, and thus, the breakup location is elliptically shaped. The thin film dynamics are modeled by a radial momentum analysis for a given jet Weber number and specified slip length and the location of breakup for multiple surfaces over a range of jet Weber numbers and realistic slip length values is quantified. The results of the analysis show that the breakup radius increases with increasing Weber number and slip length. The eccentricity of the breakup ellipse for the rib/cavity SH structures increases with increasing Weber number and slip length as well. A generalized model that allows prediction of the transition (break-up) location as a function of all influencing parameters is presented

  5. Comparison of various droplet breakup models in gas-liquid flows in high-pressure environments

    International Nuclear Information System (INIS)

    Droplet breakup affects spray penetration and evaporation, and plays a critical role in engine efficiency. The purpose of this research was to examine the rate of penetration and evaporation of droplets in a combustion chamber, and the efficiency of the engine when liquid jet is injected into the compressed gas chamber in an axi-symmetrical fashion leading to a turbulent and unsteady flow. As a result of interaction with the highly compressed air in the chamber, the liquid jet breaks up and forms minute droplets. These particles will in turn breakup because of aerodynamic forces, producing even smaller droplets. A number of models are available for analyzing the breakup of droplets; however, each model is typically reliable only over a limited parameter range. In this research three well-known models are applied for droplet breakup modeling and their results are compared. To obtain the details of the flow field, the Eulerian gas phase mass, momentum and energy conservation equations, as well as equations governing the transport of turbulence and fuel vapor mass fraction are solved together with equations of trajectory, momentum, mass and energy conservation for liquid droplets in Lagrangian form. The numerical solution is performed using the finite volume method and EPISO (Engine-PISO) algorithm. The results obtained from the models show that the breakup process in a high pressure environment significantly affects the penetration and evaporation rates of the spray, and the droplet size is determined by the balance between breakup and coalescence processes. It is also shown that the details of atomization in the nozzle do not significantly influence the ultimate size of droplets. It should be mentioned that droplet collision modeling has been taken into account in the computer code and is activated wherever necessary

  6. Monitoring ice break-up on the Mackenzie River using MODIS data

    Directory of Open Access Journals (Sweden)

    P. Muhammad

    2015-05-01

    Full Text Available This study involves the analysis of Moderate Resolution Imaging Spectroradiometer (MODIS Level 3 500 m snow products (MOD/MYD10A1, complemented with 250 m Level 1B data (MOD/MYD02QKM, to monitor ice cover during the break-up period on the Mackenzie River, Canada. Results from the analysis of data for 13 ice seasons (2001–2013 show that first day ice-off dates are observed between days of year (DOY 115–125 and end DOY 145–155, resulting in average melt durations of about 30–40 days. Floating ice transported northbound could therefore generate multiple periods of ice-on and ice-off observations at the same geographic location. During the ice break-up period, ice melt was initiated by in situ (thermodynamic melt over the drainage basin especially between 61–61.8° N (75–300 km. However, ice break-up process north of 61.8° N was more dynamically driven. Furthermore, years with earlier initiation of the ice break-up period correlated with above normal air temperatures and precipitation, whereas later ice break-up period was correlated with below normal precipitation and air temperatures. MODIS observations revealed that ice runs were largely influenced by channel morphology (islands and bars, confluences and channel constriction. It is concluded that the numerous MODIS daily overpasses possible with the Terra and Aqua polar orbiting satellites, provide a powerful means for monitoring ice break-up processes at multiple geographical locations simultaneously along the Mackenzie River.

  7. Bag breakup of low viscosity drops in the presence of a continuous air jet

    Energy Technology Data Exchange (ETDEWEB)

    Kulkarni, V., E-mail: vkulkarn@purdue.edu; Sojka, P. E. [Maurice J. Zucrow Laboratories, Purdue University, West Lafayette, Indiana 47906 (United States)

    2014-07-15

    This work examines the breakup of a single drop of various low viscosity fluids as it deforms in the presence of continuous horizontal air jet. Such a fragmentation typically occurs after the bulk liquid has disintegrated upon exiting the atomizer and is in the form of an ensemble of drops which undergo further breakup. The drop deformation and its eventual disintegration is important in evaluating the efficacy of a particular industrial process, be it combustion in automobile engines or pesticide spraying in agricultural applications. The interplay between competing influences of surface tension and aerodynamic disruptive forces is represented by the Weber number, We, and Ohnesorge number, Oh, and used to describe the breakup morphology. The breakup pattern considered in our study corresponds to that of a bag attached to a toroidal ring which occurs from ∼12 < We < ∼16. We aim to address several issues connected with this breakup process and their dependence on We and Oh which have been hitherto unexplored. The We boundary at which breakup begins is theoretically determined and the expression obtained, We=12(1+2/3Oh{sup 2}), is found to match well with experimental data ([L.-P. Hsiang and G. M. Faeth, Int. J. Multiphase Flow 21(4), 545–560 (1995)] and [R. S. Brodkey, “Formation of drops and bubbles,” in The Phenomena of Fluid Motions (Addison-Wesley, Reading, 1967)]). An exponential growth in the radial extent of the deformed drop and the streamline dimension of the bag is predicted by a theoretical model and confirmed by experimental findings. These quantities are observed to strongly depend on We. However, their dependence on Oh is weak.

  8. Computational modeling of ice cracking and break-up from helicopter blades

    KAUST Repository

    Shiping, Zhang

    2012-06-25

    In order to reduce the danger of impact onto components caused by break-up, it is important to analyze the shape of shed ice accumulated during flight. In this paper, we will present a 3D finite element method (FEM) to predict the shed ice shape by using a fluid-solid interaction (FSI) approach to determine the loads, and linear fracture mechanics to track crack propagation. Typical icing scenarios for helicopters are analyzed, and the possibility of ice break-up is investigated.

  9. 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

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

    International Nuclear Information System (INIS)

    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

  11. Coupled simulations of nozzle flow, primary fuel jet breakup, and spray formation

    OpenAIRE

    Berg, Eberhard von; Edelbauer, Wilfried; Alajbegović, Aleš; Tatschl, Reinhard; Volmajer, Martin; Kegl, Breda; Ganippa, Lionel C.

    2012-01-01

    Presented are two approaches for coupled simulations of the injector flow withspray formation. In the first approach the two-fluid model is used within the injector for the cavitating flow. A primary breakup model is then applied at the nozzle orifice where it is coupled with the standard discrete droplet model. In the second approach the Eulerian multi-fluid model is applied for both the nozzle and spray regions. The developed primary breakup model, used in both approaches, is based on local...

  12. Monitoring ice break-up on the Mackenzie River using MODIS data

    Science.gov (United States)

    Muhammad, P.; Duguay, C.; Kang, K.-K.

    2016-03-01

    The aim of this study was to develop an approach for estimating ice break-up dates on the Mackenzie River (MR) using more than a decade of MODIS Level 3 500 m snow products (MOD/MYD10A1), complemented with 250 m Level 1B radiance products (MOD/MYD02QKM) from the Terra and Aqua satellite platforms. The analysis showed break-up began on average between days of year (DOYs) 115 and 125 and ended between DOYs 145 and 155 over 13 ice seasons (2001-2013), resulting in an average melt duration of ca. 30-40 days. Thermal processes were more important in driving ice break-up south of the MR confluence with the Liard River, while dynamically driven break-up was more important north of the Liard. A comparison of the timing of ice disappearance with snow disappearance from surrounding land areas of the MR with MODIS Level 3 snow products showed varying relationships along the river. Ice-off and snow-off timing were in sync north of the MR-Liard River confluence and over sections of the MR before it enters the Mackenzie Delta, but ice disappeared much later than snow on land in regions where thermal ice break-up processes dominated. MODIS observations revealed that channel morphology is a more important control of ice break-up patterns than previously believed with ice runs on the MR strongly influenced by channel morphology (islands and bars, confluences and channel constriction). Ice velocity estimates from feature tracking were able to be made in 2008 and 2010 and yielded 3-4-day average ice velocities of 1.21 and 1.84 m s-1 respectively, which is in agreement with estimates from previous studies. These preliminary results confirm the utility of daily MODIS data for monitoring ice break-up processes along the Mackenzie River. The addition of optical and synthetic aperture radar data from recent and upcoming satellite missions (e.g. Sentinel-1/2/3 and RADARSAT Constellation) would improve the monitoring of ice break-up in narrower sections of the MR.

  13. Configuration space Faddeev equations within the general formalism for studying Nd breakup scattering

    Science.gov (United States)

    Suslov, Vladimir; Braun, Mikhail; Filikhin, Igor; Vlahovic, Branislav; Slaus, Ivo

    2015-10-01

    Appropriate modifications of the configuration space Faddeev equations have been made to study the three-nucleon system assuming the neutrons and protons to be distinguishable. Breakup amplitudes for n-d and p-d scattering at Elab =14.1 MeV are calculated in s-wave approach with the Malfliet-Tjon MT I-III and AV14 potentials. Results obtained for Nd breakup scattering in quartet and doublet spin states are compared with our predictions and those of the Los-Alamos/Iowa group. This work is supported by NSF CREST (HRD-0833184).

  14. Nd isotope constraints on ocean circulation, paleoclimate, and continental drainage during the Jurassic breakup of Pangea

    DEFF Research Database (Denmark)

    Dera, Guillaume; Prunier, Jonathan; Smith, Paul L.;

    2015-01-01

    The breakup of Pangea and onset of growth of the Pacific plate led to several paleoenvironmental feedbacks, which radically affected paleoclimate and ocean chemistry during the Jurassic. Overall, this period was characterized by intense volcanic degassing from large igneous provinces and circum...... unradiogenic Arctic waters occurred in the NW Tethys in the Callovian-Early Oxfordian. All these results show that changes in surface oceanic circulation resulting from the Pangean breakup could have regionally impacted the evolution of seawater temperatures in the NW Tethys....

  15. Three-body Coulomb breakup of 11Li in the complex scaling method

    OpenAIRE

    Myo, T.; Aoyama, S.; Kato, K.; Ikeda, K.

    2003-01-01

    Coulomb breakup strengths of 11Li into a three-body 9Li+n+n system are studied in the complex scaling method. We decompose the transition strengths into the contributions from three-body resonances, two-body ``10Li+n'' and three-body ``9Li+n+n'' continuum states. In the calculated results, we cannot find the dipole resonances with a sharp decay width in 11Li. There is a low energy enhancement in the breakup strength, which is produced by both the two- and three-body continuum states. The enha...

  16. Is the breakup time a free parameter when describing heavy ion collisions?

    International Nuclear Information System (INIS)

    Thermodinamic descriptions of heavy ion collisions generally include the so called breakup time (when to switch from continuum picture to a collisionless gas). While an appropriate choice of this time can help to reproduce the detected spectra, from the same reason this freedom may prevent us to reconstruct uniquely the compressed hot stages from the observables. This problem is absent if the calculated final spectra are insensitive on the breakup time at least in a domain. Here we show such an example in a model system. This example may give further arguments for the thermodynamic description. (author) 13 refs.; 4 figs

  17. Coulomb versus nuclear break-up of 11Be halo nucleus in a non perturbative framework

    CERN Document Server

    Fallot, M; Lacroix, D; Chomaz, P; Margueron, J; Chomaz, Ph.

    2002-01-01

    The 11Be break-up is calculated using a non perturbative time-dependent quantum calculation. The evolution of the neutron halo wave function shows an emission of neutron at large angles for grazing impact parameters and at forward angles for large impact parameters. The neutron angular distribution is deduced for the different targets and compared to experimental data. We emphasize the diversity of diffraction mechanisms, in particular we discuss the interplay of the nuclear effects such as the towing mode and the Coulomb break-up. A good agreement is found with experimental data.

  18. Nucleon-nucleon scattering length from three-body reactions

    International Nuclear Information System (INIS)

    Experiments aimed at the measurement of the singlet scattering lengths 1anp and 1ann of the NN-interaction in the presence of a heavy spectator are described. The values obtained are compared with the results of measurements of other reactions. The very good agreement of the experimental values of 1anp from all breakup reactions and elastic scattering as well as agreement of the values of 1ann from breakup reactions and disagreement with the value from the π-d → nnγ reaction cast doubts on the hypothesis ascribing this discrepancy to a 3N-force. This result also suggests a stronger effect of a violation of the charge independence principle than previously accepted. 101 refs., 18 figs., 3 tabs. (author)

  19. Many-body Quantum Reaction Dynamics near the Fusion Barrier

    Directory of Open Access Journals (Sweden)

    Dasgupta M.

    2014-03-01

    Full Text Available The understanding of quantum effects in determining nuclear reaction outcomes is evolving as improved experimental techniques reveal new facets of interaction dynamics. Whilst the phenomenon of coupling-enhanced quantum tunnelling is understood to arise due to quantum superposition, the observed inhibition of fusion at energies well below the barrier is not yet quantitatively understood. Collisions involving weakly-bound nuclei, which have low energy thresholds against breakup, present further challenges. Recent coincidence measurements for reactions of weakly bound stable nuclei have not only provided a complete picture of the physical mechanisms triggering breakup, but have also shown how information on reaction dynamics occurring on time-scales of ~zepto-seconds can be obtained experimentally. These new experimental findings demand major developments in quantum models of near-barrier nuclear reactions.

  20. Many-body quantum reaction dynamics near the fusion barrier

    International Nuclear Information System (INIS)

    The understanding of quantum effects in determining nuclear reaction outcomes is evolving as improved experimental techniques reveal new facets of interaction dynamics. Whilst the phenomenon of coupling-enhanced quantum tunnelling is understood to arise due to quantum superposition, the observed inhibition of fusion at energies well below the barrier is not yet quantitatively understood. Collisions involving weakly-bound nuclei, which have low energy thresholds against breakup, present further challenges. Recent coincidence measurements for reactions of weakly bound stable nuclei have not only provided a complete picture of the physical mechanisms triggering breakup, but have also shown how information on reaction dynamics occurring on time-scales of ∼ zepto-seconds can be obtained experimentally. These new experimental findings demand major developments in quantum models of near-barrier nuclear reactions. (authors)

  1. Experimental study of drop breakup in a turbulent flow; Etude experimentale de la rupture de gouttes dans un ecoulement turbulent

    Energy Technology Data Exchange (ETDEWEB)

    Galinat, S.

    2005-04-15

    This work presents the drop breakup phenomenon in a turbulent flow induced by a cross-section restriction in a pipe. A global analysis of single-drop breakup, in a finite volume downstream of the orifice, has allowed deriving statistical quantities such as the break-up probability and the daughter-drop distribution. These parameters are function of a global Weber number based on the maximal pressure drop through the orifice. At a local scale, the locations of breakup events are distributed heterogeneously and depend on the flow Reynolds number. The local hydrodynamic study in downstream of the orifice, which has been done by using Particle Image Velocimetry, reveals the specific breakup zones. Otherwise, this analysis has proved that the turbulence is the predominant external stress at the drop scale. The relation between drop deformation and the external stress along the trajectory has been simulated numerically by the response of a damped oscillator to the locally measured instantaneous turbulence forcing. The results of statistical analysis have allowed to introduce a breakup criterion, based on a unique deformation threshold value for all experiments. This multi-scale approach has been conducted to study drop breakup mechanisms in a concentrated dispersion. The breakup probability decrease with the increase of dispersed phase concentration, which influences the turbulent Weber number distribution in downstream of the orifice. (author)

  2. Inclusive measurements of the break-up of 156 MeV 6Li-ions at extreme forward angles and the quasi free break-up model

    International Nuclear Information System (INIS)

    Inclusive alpha particle and deuteron spectra from collisions of 156 MeV 6Li-ions with 12C and 208Pb were measured at extreme forward emission angles including zero degree. The measurements were performed with the Karlsruhe magnetic spectrograph 'Little John' and required an efficient reduction of the background from small-angle scattering. The observed double differential cross sections and angular distributions have been analysed on the basis of Serber's spectator break-up model. When going to angles smaller than grazing, where Coulomb effects are expected to the dominating, transitional features may appear. Corresponding effects probably associated with Coulomb break-up are observed with the 208Pb-target and require a slight extension of the Serber approach. In the case of the 12C-target the break-up cross sections in forward direction seem to reflect the shape of the internal momentum distribution of the alpha particle and deuteron cluster in the 6Li-projectile and are in agreement with a 2S-type wave function. However, at larger angles the shape appears to be distorted, possibly by final state interactions. (orig.)

  3. Multinucleon transfer reactions

    International Nuclear Information System (INIS)

    Nuclear reactions induced by complex nuclei are studied. The description of the single neutron transfer is used to show some aspect of the theoretical treatment of transfer reactions and rules concerning the dependence of cross sections on quantum numbers of the initial and final channels are deduced. Strongly excited states of 20Ne, 19F, sup(16,17)0, 15N were studied experimentally by using different projectile-target combinations in the four-particle, eight-particle and ten-particle transfer reactions, leading to the some final nuclei. Obtained results are discussed. In addition, studies of the projectile break-up phenomenon were performed. The dissociation of 6Li and 7Li projectiles was investigated in reactions on Pb, Sn and Ni nuclei. These nuclei were chosen to allow measurements at one incident energy below, above and at the Coulomb barrier. The observed spectra indicate that the process proceeds primarily via the resonance level but the shape deviates from the shape which was calculated assuming isotropic decay of the excited 6Li in its center of mass system. The investigations of the elastic scattering turned out to be more fruitful and allowed to define better the Coulomb barrier for the 6Li-target system. (S.B.)

  4. Finite Range Effects on Fusion and/or Breakup of 6He+238U and 11Li+208Pb Systems

    Institute of Scientific and Technical Information of China (English)

    Sukhvinder S. Duhan; Manjeet Singh; Rajesh Kharab; H.C. Sharma

    2011-01-01

    We have studied the effects of the finite range of the interaction between the fragments of the projectile on the fusion and/or breakup of 6He+238U and 11 Li+208 Pb systems at near barrier energies within the framework of dynamic polarization potential approach.It has been found that at near barrier energies the maximum flux is lost to the breakup channel and at energies well above the Coulomb barrier the fusion coupled with the breakup channel opens up, initially with sharp rise and later becoming saturated at energy nearly twice of the Coulomb barrier.Further, it is found that the breakup cross section increases with the increasing range of the interaction between the fragments of the projectile while the fusion coupled with the breakup channel cross section decreases with the increasing range.

  5. Breakup of 96 MeV α-particles in the 58,64Ni niclei fields

    International Nuclear Information System (INIS)

    The aim of the paper is to investigate the process of α-particle breakup into two deuterons and to estimate the applicability of data on breakup for extraction of diffusivity parameter (a) in the framework of the diffraction approach. Measurements of absolute values of differential cross sections (DCS) of 96 MeV α-particle breakup on 58,64Ni are carried out in the limited angular range: Θ1=22.5 deg, Θ2=50, 55, 60, -50, -60 deg. Wide maxima typical for the process of incident α-particle breakup are observed in deuteron energy spectra. Measured DCS for α-particle breakup show distinct difference for 58Ni and 64Ni. The calculations describe satisfactorily this difference in the framework of the diffraction approach, if it is supposed that the diffusivity parameter for 58Ni nucleus has the value a=0.65 fm, and for 64Ni - a=0.85 fm

  6. Theoretical Model Calculation for d + 8Li Reaction

    Institute of Scientific and Technical Information of China (English)

    HAN Yin-Lu; GUO Hai-Rui; ZHANG Yue; ZHANG Jing-Shang

    2008-01-01

    Based on the theoretical models for light nuclei, the calculations of reaction cross sections and the angular distributions for d+8Li reaction are performed. Since all of the particle emissions are from the compound nucleus to the discrete levels, the angular momentum coupling effect in pre-equilibrium mechanism is taken into account. The three-body break-up process and the recoil effect are involved. The theoretical calculated results are compared to existing experimental data.

  7. From the Coulomb breakup of halo nuclei to neutron radiative capture

    CERN Document Server

    Capel, Pierre

    2016-01-01

    Coulomb breakup is used to infer radiative-capture cross sections at astrophysical energies. We test theoretically the accuracy of this indirect technique in the particular case of 15C, for which both the Coulomb breakup to ^{14}C+n and the radiative capture 14C(n,{\\gamma})15C have been measured. We analyse the dependance of Coulomb-breakup calculations on the projectile description in both its initial bound state and its continuum. Our calculations depend not only on the Asymptotic Normalisation Coefficient (ANC) of the 15C ground state, but also on the 14C-n continuum. This questions the method proposed by Summers and Nunes [Phys. Rev. C 78, 011601 (2008), ibid. 78, 069908 (2008)], which assumes that an ANC can be directly extracted from the comparison of calculations to breakup data. Fortunately, the sensitivity to the continuum description can be absorbed in a normalisation constant obtained by a simple {\\chi}2 fit of our calculations to the measurements. By restricting this fit to low 14C-n energy in the...

  8. Bag breakup of low viscosity drops in the presence of a continuous air jet

    International Nuclear Information System (INIS)

    This work examines the breakup of a single drop of various low viscosity fluids as it deforms in the presence of continuous horizontal air jet. Such a fragmentation typically occurs after the bulk liquid has disintegrated upon exiting the atomizer and is in the form of an ensemble of drops which undergo further breakup. The drop deformation and its eventual disintegration is important in evaluating the efficacy of a particular industrial process, be it combustion in automobile engines or pesticide spraying in agricultural applications. The interplay between competing influences of surface tension and aerodynamic disruptive forces is represented by the Weber number, We, and Ohnesorge number, Oh, and used to describe the breakup morphology. The breakup pattern considered in our study corresponds to that of a bag attached to a toroidal ring which occurs from ∼12 2), is found to match well with experimental data ([L.-P. Hsiang and G. M. Faeth, Int. J. Multiphase Flow 21(4), 545–560 (1995)] and [R. S. Brodkey, “Formation of drops and bubbles,” in The Phenomena of Fluid Motions (Addison-Wesley, Reading, 1967)]). An exponential growth in the radial extent of the deformed drop and the streamline dimension of the bag is predicted by a theoretical model and confirmed by experimental findings. These quantities are observed to strongly depend on We. However, their dependence on Oh is weak

  9. Measurement of the Time Course of Optical Quality and Visual Deterioration during Tear Break-Up

    OpenAIRE

    Liu, Haixia; THIBOS, LARRY; Begley, Carolyn G.; Bradley, Arthur

    2010-01-01

    In this study, a new optical system was developed that simultaneously measured optical quality and visual performance during monitoring of tear film instability. The results confirmed that blurry vision symptoms reported by contact lens patients are caused by the poor quality of the retinal image due to tear break-up.

  10. Breakup of the projectile in heavy ion collisions at intermediate energies

    International Nuclear Information System (INIS)

    Report on an experiment in which the 4He breakup channel of 16O projectiles on various targets (27Al, 58Ni, 197Au) has been studied inclusively, and exclusively (in coincidence with charged pions). The bombarding energy was 94 MeV/nucleon. (D.L.). 7 refs., 5 figs

  11. DebriSat - A Planned Laboratory-Based Satellite Impact Experiment for Breakup Fragment Characterizations

    Science.gov (United States)

    Liou, Jer-Chyi; Clark, S.; Fitz-Coy, N.; Huynh, T.; Opiela, J.; Polk, M.; Roebuck, B.; Rushing, R.; Sorge, M.; Werremeyer, M.

    2013-01-01

    The goal of the DebriSat project is to characterize fragments generated by a hypervelocity collision involving a modern satellite in low Earth orbit (LEO). The DebriSat project will update and expand upon the information obtained in the 1992 Satellite Orbital Debris Characterization Impact Test (SOCIT), which characterized the breakup of a 1960 s US Navy Transit satellite. There are three phases to this project: the design and fabrication of DebriSat - an engineering model representing a modern, 60-cm/50-kg class LEO satellite; conduction of a laboratory-based hypervelocity impact to catastrophically break up the satellite; and characterization of the properties of breakup fragments down to 2 mm in size. The data obtained, including fragment size, area-to-mass ratio, density, shape, material composition, optical properties, and radar cross-section distributions, will be used to supplement the DoD s and NASA s satellite breakup models to better describe the breakup outcome of a modern satellite.

  12. Characterization of the 2012-044c Briz-M Upper Stage Breakup

    Science.gov (United States)

    Matney, M. J.; Hamilton, Joseph; Papanyan, Valen

    2013-01-01

    On 6 August, 2012, Russia launched two commercial satellites aboard a Proton rocket, and attempted to place them in geosynchronous orbit using a Briz-M upper stage (2012-044C, SSN 38746). Unfortunately, the upper stage failed early in its burn and was left stranded in an elliptical orbit with a perigee in low Earth orbit (LEO). Because the stage failed with much of its fuel on board, it was deemed a significant breakup risk. These fears were confirmed when it broke up 16 October, creating a large cloud of debris with perigees below that of the International Space Station. The debris cloud was tracked by the US Space Surveillance Network (SSN), which can reliably detect and track objects down to about 10 cm in size. Because of the unusual geometry of the breakup, there was an opportunity for NASA Orbital Debris Program Office to request radar assets to characterize the extent of the debris cloud in sizes smaller than the standard debris tracked by the SSN. This paper will describe the observation campaign to measure the small particle distributions of this cloud, and presents the results of the analysis of the data. We shall compare the data to the modelled size distribution, number, and shape of the cloud, and what implications this may have for future breakup debris models. We shall conclude the paper with a discussion how this measurement process can be improved for future breakups.

  13. Bouncing Back from a Breakup: Attachment, Time Perspective, Mental Health, and Romantic Loss

    Science.gov (United States)

    Gilbert, Steven P.; Sifers, Sarah K.

    2011-01-01

    Coping with a romantic breakup is a normal developmental task of emerging adulthood. Because of their role in influencing interpersonal relationships and adjustment, attachment history and time perspectives may influence resilience to romantic loss. In an online survey of 1,404 university students ages 18-25 who reported experiencing recent…

  14. Type of Writing Task and College Students' Meaning Making Following a Romantic Breakup

    Science.gov (United States)

    Primeau, Joanna E.; Servaty-Seib, Heather L.; Enersen, Donna

    2013-01-01

    In this study, the authors examined the potential effects of type of writing task (loss/gain vs. general prompt) on the narrative content offered by college students (N = 41) who experienced romantic breakup. Qualitative analyses indicated differences based on type of writing task. Students who received the loss/gain prompt exhibited more…

  15. Large-eddy simulation of cavitating nozzle flow and primary jet break-up

    NARCIS (Netherlands)

    Örley, F.; Trummler, T.; Hickel, S.; Mihatsch, M.S.; Schmidt, S.J.; Adams, N.A.

    2015-01-01

    We employ a barotropic two-phase/two-fluid model to study the primary break-up of cavitating liquid jets emanating from a rectangular nozzle, which resembles a high aspect-ratio slot flow. All components (i.e., gas, liquid, and vapor) are represented by a homogeneous mixture approach. The cavitating

  16. Deformation pathways and breakup modes in acoustically levitated bicomponent droplets under external heating

    Science.gov (United States)

    Pathak, Binita; Basu, Saptarshi

    2016-03-01

    Controlled breakup of droplets using heat or acoustics is pivotal in applications such as pharmaceutics, nanoparticle production, and combustion. In the current work we have identified distinct thermal acoustics-induced deformation regimes (ligaments and bubbles) and breakup dynamics in externally heated acoustically levitated bicomponent (benzene-dodecane) droplets with a wide variation in volatility of the two components (benzene is significantly more volatile than dodecane). We showcase the physical mechanism and universal behavior of droplet surface caving in leading to the inception and growth of ligaments. The caving of the top surface is governed by a balance between the acoustic pressure field and the restrictive surface tension of the droplet. The universal collapse of caving profiles for different benzene concentration (growth. Subsequent ligament breakup is primarily Rayleigh-Plateau type. The breakup mode shifts to diffusional entrapment-induced boiling with an increase in concentration of the volatile component (benzene >70 % by volume). The findings are portable to any similar bicomponent systems with differential volatility.

  17. Sharing Remote and Local Information for Tracking Spring Breakup in the Mackenzie Delta and Beaufort Sea

    Science.gov (United States)

    Forbes, D. L.; Whalen, D.; Fraser, P.

    2015-12-01

    The Mackenzie Delta is the second largest on the Arctic Ocean, covering 13 000 km2. The annual flood regime in the delta is dominated by the spring snowmelt freshet and associated ice breakup, as water from the south arrives in the ice-covered delta and spreads over bottomfast and adjacent floating sea ice at the delta front. The complex processes of water-ice interaction, flow partitioning, and overbank flooding to replenish waters in 43 000 delta lakes threaten community, transportation, subsistence, and energy infrastructure in the delta. The annual breakup season is a time of rejuvenation, excitement, and anxiety for delta residents and stakeholders. To track the progress of breakup and meet the need for knowledge dissemination to the local communities, a Mackenzie-Beaufort breakup newsletter has been produced by Natural Resources Canada on a quasi-daily basis during the May-June spring flood season for 10 years, and distributed to an e-mail list that grew to over 300 subscribers. This provides near real-time tracking of water levels and breakup using on-line gauges (Environment Canada), daily MODIS satellite imagery (NASA), Landsat imagery (USGS) and intermittent radar imagery (various sources). In earlier years, information was also supplied from field programs operating in the delta during breakup, but changing priorities and funding have reduced the number of outside researchers present during these critical weeks. Meanwhile the number of local contributors has grown, providing observations and photographs to share with the local, regional and global readership. In this way the newsletter evolved into a two-way communication tool and community portal. The newsletter is a chronicle of each breakup season and a key resource for territorial and municipal managers, subsistence organizations, and emergency response agencies, with routine requests for specific imagery in areas of concern. With the completion of 10 years under the present model, we are exploring

  18. Post-breakup Basin Evolution along the South-Atlantic Margins

    Science.gov (United States)

    Strozyk, Frank; Back, Stefan; Kukla, Peter

    2014-05-01

    The post-breakup tectono-stratigraphic evolution of large offshore basins along the South American and African continental margins record strongly varying post-rift sedimentary successions. The northernmost segment of the South Atlantic rift and salt basins is characterized by a pronounced asymmetry, with the Brazilian margin comprising narrower and deeper rift basins with less salt in comparison to the Congo-Gabon conjugate margin. Another important observation is that multiple phases of uplift and subsidence are recorded after the break-up of the southern South Atlantic on both sides of the Florianopolis-Walvis Ridge volcanic complex, features that are regarded as atypical when compared to published examples of other post-breakup margin successions. A regional comparison based on tectonic-stratigraphic analysis of selected seismic transects between the large basins offshore southern Brazil (Espirito Santo Basin, Campos Basin, Santos Basin, Pelotas Basin) and southwest Africa (Lower Congo Basin, Kwanza Basin, Namibe Basin, Walvis Basin) provides a comprehensive basin-to-basin documentation of the key geological parameters controlling ocean and continental margin development. This comparison includes the margin configuration, subsidence development through time, sediment influx and storage patterns, type of basin fill (e.g. salt vs. non-salt systems; carbonate-rich vs. clastics-dominated systems) and finally major tectonic and magmatic events. Data from the salt basins indicate that salt-related tectonic deformation is amongst the prime controls for the non-uniform post-rift margin development. The diversity in the stratigraphic architecture of the conjugate margins offshore southern Brazil, Namibia and Angola reflects variations in the interplay of a number of controlling factors, of which the most important are (a) the structural configuration of each margin segment at the time of break-up, (b) the post break-up subsidence history of the respective margin segment

  19. DebriSat - A Planned Laboratory-Based Satellite Impact Experiment for Breakup Fragment Characterization

    Science.gov (United States)

    Liou, J.-C.; Fitz-Coy, N.; Werremeyer, M.; Huynh, T.; Voelker, M.; Opiela, J.

    2012-01-01

    DebriSat is a planned laboratory ]based satellite hypervelocity impact experiment. The goal of the project is to characterize the orbital debris that would be generated by a hypervelocity collision involving a modern satellite in low Earth orbit (LEO). The DebriSat project will update and expand upon the information obtained in the 1992 Satellite Orbital Debris Characterization Impact Test (SOCIT), which characterized the breakup of a 1960 's US Navy Transit satellite. There are three phases to this project: the design and fabrication of an engineering model representing a modern, 50-cm/50-kg class LEO satellite known as DebriSat; conduction of a laboratory-based hypervelocity impact to catastrophically break up the satellite; and characterization of the properties of breakup fragments down to 2 mm in size. The data obtained, including fragment size, area ]to ]mass ratio, density, shape, material composition, optical properties, and radar cross ]section distributions, will be used to supplement the DoD fs and NASA fs satellite breakup models to better describe the breakup outcome of a modern satellite. Updated breakup models will improve mission planning, environmental models, and event response. The DebriSat project is sponsored by the Air Force fs Space and Missile Systems Center and the NASA Orbital Debris Program Office. The design and fabrication of DebriSat is led by University of Florida with subject matter experts f support from The Aerospace Corporation. The major milestones of the project include the complete fabrication of DebriSat by September 2013, the hypervelocity impact of DebriSat at the Air Force fs Arnold Engineering Development Complex in early 2014, and fragment characterization and data analyses in late 2014.

  20. Two-valued breakup length of a water jet issuing from a finite-length nozzle under normal gravity.

    Science.gov (United States)

    Umemura, Akira; Kawanabe, Sho; Suzuki, Sousuke; Osaka, Jun

    2011-09-01

    Laboratory experiments are conducted in which water is issued vertically downward from a finite-length nozzle at a constant speed using a piston. The results of these experiments indicate that the breakup length of the liquid jet is two-valued at Weber numbers greater than unity but less than a certain value, which depends on the nozzle length-to-radius ratio and the Bond number. In addition to a long breakup length, which is consistent with the conventional observation, another shorter breakup length is realized at the same jet issue speed. Each experimental run for a specific jet issue speed begins from the start of liquid issue so that each run is independent of the other runs. Transition between the two breakup lengths seldom occurs in each run. Which of the two breakup lengths occurs is determined at the start of liquid issue, when the capillary wave produced by the liquid jet tip contraction easily reaches the nozzle exit. Unlike the conventional belief, which is based on the Plateau-Rayleigh instability theory, this experimental evidence demonstrates that liquid jet disintegration occurs in a deterministic manner. The previously proposed self-destabilizing mechanism of a liquid jet in microgravity, in which the origin of the unstable wave responsible for the breakups is attributed to the formation of an upstream propagating capillary wave at every breakup, is extended to explore the physics underlying the observed liquid jet disintegration behaviors. PMID:22060494

  1. Attachment styles and personal growth following romantic breakups: the mediating roles of distress, rumination, and tendency to rebound.

    Directory of Open Access Journals (Sweden)

    Tara C Marshall

    Full Text Available The purpose of this research was to examine the associations of attachment anxiety and avoidance with personal growth following relationship dissolution, and to test breakup distress, rumination, and tendency to rebound with new partners as mediators of these associations. Study 1 (N = 411 and Study 2 (N = 465 measured attachment style, breakup distress, and personal growth; Study 2 additionally measured ruminative reflection, brooding, and proclivity to rebound with new partners. Structural equation modelling revealed in both studies that anxiety was indirectly associated with greater personal growth through heightened breakup distress, whereas avoidance was indirectly associated with lower personal growth through inhibited breakup distress. Study 2 further showed that the positive association of breakup distress with personal growth was accounted for by enhanced reflection and brooding, and that anxious individuals' greater personal growth was also explained by their proclivity to rebound. These findings suggest that anxious individuals' hyperactivated breakup distress may act as a catalyst for personal growth by promoting the cognitive processing of breakup-related thoughts and emotions, whereas avoidant individuals' deactivated distress may inhibit personal growth by suppressing this cognitive work.

  2. Experimental Characteristics of Viscous Fluid Secondary Breakup%黏性流体的二次雾化特性

    Institute of Scientific and Technical Information of China (English)

    蒋德军; 赵辉; 刘海峰; 王辅臣; 于遵宏

    2011-01-01

    The glycerol solution was chosen as the substitute liquid of asphalt residue at high temperature firstly to probe its atomization characteristics. Then, the experimental observations on the secondary breakup of single droplet in glycerol solution were performed by using high speed camera. From observation and analysis, the deformation and breakup characteristics of droplet, such as breakup mode, characteristic size, breakup time and average droplet diameter were obtained, respectively. As We number increased, the droplet breakup of glycerol solution showed five different modes: bag breakup, bag-stamen breakup, dual-bag breakup, shear breakup and catastrophic breakup. At low We number, the dimensionless maximum cross stream size of the droplet at the onset of breakup was constant. And at high We number, the total breakup time was very short, and the diameter of fragment was exceeding small, which is beneficial to atomization.%针对渣油沥青气化工艺,以高温下渣油沥青的雾化为研究背景,选择与其物性相近的甘油水溶液作为模拟介质,进行了黏性液体二次雾化的实验.利用高速摄像仪和图像处理软件,对单个液滴在不同条件下的破裂模式、特征尺度、破裂时间和破裂后的平均液滴直径等进行了观察和分析.结果表明,随着韦伯数(We)的增加,甘油液滴的破裂依次呈现5种不同的模式:袋状破裂、袋状-雄蕊破裂、双重袋状破裂、剪切破裂和爆发式破裂.在低We下,液滴直径最大变形率基本相同;在高We下,总破裂时间明显缩短,破裂产生的液滴粒径很小,雾化效果良好.

  3. Development of the VESUVIUS code for steam explosion analysis. Pt.2: verification of jet breakup modeling

    Energy Technology Data Exchange (ETDEWEB)

    Vierow, K.; Naitoh, Masanori [Nuclear Power Engineering Corp., Tokyo (Japan); Nagano, Katsuhiro; Araki, Kazuhiro

    1998-12-01

    In the comparison Part 1 paper, the jet breakup model incorporated into the VESUVIUS code was described. Herein, initial verification of the VESUVIUS jet breakup modeling by comparison of calculation results against the PREMIX PM10 and FARO L-14 experimental data is discussed. Predictions of the main experimental parameters, which include steam outlet flow rate and interaction region` development for the PREMIX test and test vessel pressure and level swell for the FARO test, are shown to be in good agreement with the test data. In addition, the change with time of the jet axial profile and two-dimensional spatial distributions of the jet and coolant, which are not available as experimental data, are discussed in an attempt to further clarify molten jet behavior. (author)

  4. Deformation pathways and breakup modes in acoustically levitated bicomponent droplets under external heating

    Science.gov (United States)

    Pathak, Binita; Basu, Saptarshi

    2016-03-01

    Controlled breakup of droplets using heat or acoustics is pivotal in applications such as pharmaceutics, nanoparticle production, and combustion. In the current work we have identified distinct thermal acoustics-induced deformation regimes (ligaments and bubbles) and breakup dynamics in externally heated acoustically levitated bicomponent (benzene-dodecane) droplets with a wide variation in volatility of the two components (benzene is significantly more volatile than dodecane). We showcase the physical mechanism and universal behavior of droplet surface caving in leading to the inception and growth of ligaments. The caving of the top surface is governed by a balance between the acoustic pressure field and the restrictive surface tension of the droplet. The universal collapse of caving profiles for different benzene concentration (70 % by volume). The findings are portable to any similar bicomponent systems with differential volatility.

  5. Theoretical study of the elastic breakup of weakly bound nuclei at near barrier energies

    CERN Document Server

    Otomar, D R; Lubian, J; Canto, L F; Hussein, M S

    2015-01-01

    We have performed CDCC calculations for collisions of $^{7}$Li projectiles on $^{59}$Co, $^{144}$Sm and $^{208}$Pb targets at near-barrier energies, to assess the importance of the Coulomb and the nuclear couplings in the breakup of $^{7}$Li, as well as the Coulomb-nuclear interference. We have also investigated scaling laws, expressing the dependence of the cross sections on the charge and the mass of the target. This work is complementary to the one previously reported by us on the breakup of $^{6}$Li. Here we explore the similarities and differences between the results for the two Lithium isotopes. The relevance of the Coulomb dipole strength at low energy for the two-cluster projectile is investigated in details.

  6. Breakup and deformation of a droplet falling in a miscible solution.

    Science.gov (United States)

    Shimokawa, Michiko; Mayumi, Ryosei; Nakamura, Taiki; Takami, Toshiya; Sakaguchi, Hidetsugu

    2016-06-01

    When a droplet with a higher density falls in a miscible solution, the droplet deforms and breaks up. The instability of a vortex ring, formed by droplet deformation during the falling process, causes the breakup. To determine the origin of the instability, the wavelengths and thicknesses of the vortex rings are investigated at the time when the instability occurs. The experimental results are almost in agreement with the calculated results for the Rayleigh-Taylor instability using the thickness of a higher-density solution. Furthermore, we performed simulations considering the torus shapes and circulations of the vortex ring. The simulations provided patterns similar to those observed experimentally for the breakup process, and showed that the circulations suppress the instability of the vortex ring. These results imply that the Rayleigh-Taylor instability plays a dominant role in the instability of vortex rings. PMID:27415262

  7. Study of Ground State Wave-function of the Neutron-rich 29,30Na Isotopes through Coulomb Breakup

    Directory of Open Access Journals (Sweden)

    Rahaman A.

    2014-03-01

    Full Text Available Coulomb breakup of unstable neutron rich nuclei 29,30Na around the ‘island of inversion’ has been studied at energy around 434 MeV/nucleon and 409 MeV/nucleon respectively. Four momentum vectors of fragments, decay neutron from excited projectile and γ-rays emitted from excited fragments after Coulomb breakup are measured in coincidence. For these nuclei, the low-lying dipole strength above one neutron threshold can be explained by direct breakup model. The analysis for Coulomb breakup of 29,30Na shows that large amount of the cross section yields the 28Na, 29Na core in ground state. The predominant ground-state configuration of 29,30Na is found to be 28Na(g.s⊗νs1/2 and 29Na(g.s⊗νs1/2,respectively.

  8. Study of the Beta-delayed multiple particle break-up of the 2.43 MeV state in Be-9

    Science.gov (United States)

    Madurga Flores, Miguel; Borge, M. J. G.; Fynbo, H. O. U.; Jonson, B.; Nyman, G.; Prezado, Y.; Riisager, K.

    The aim of this work is to study the β -delayed multiparticle break-up of the 5/2- state in 9 Be at 2.43 MeV excitation energy. This process is relevant as it has been proposed recently that this level plays a role in the α(αn,γ)9 Be reaction. This state breaks-up in 2α+n, and sequential as well as direct ("democratic") decay have previously been considered. In our work energy and direction of the two emitted α particles has been measured, while those of the neutron have been reconstructed. The sequential decay is considered using the R-matrix formalism. For the democratic decay the hyper-spherical harmonics functions are used. The different decay processes are compared with the data using the Monte-Carlo method. Our preliminary results indicate that the data is better described when democratic decay is assumed.

  9. Spatial versus temporal deterministic wave breakup of nonlinearly coupled light waves.

    Science.gov (United States)

    Salerno, D; Minardi, S; Trull, J; Varanavicius, A; Tamosauskas, G; Valiulis, G; Dubietis, A; Caironi, D; Trillo, S; Piskarskas, A; Di Trapani, P

    2003-10-01

    We investigate experimentally the competition between spatial and temporal breakup due to modulational instability in chi((2)) nonlinear mixing. The modulation of the wave packets caused by the energy exchange between fundamental and second-harmonic components is found to be the prevailing trigger mechanism which, according to the relative weight of diffraction and dispersion, leads to the appearance of a multisoliton pattern in the low-dimensional spatial or temporal domain.

  10. Proton-deuteron breakup cross sections in collinear geometry at 28. 6 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Birchall, J.; Svenne, J.P.; de Jong, M.S.; McKee, J.S.C.; Ramsay, W.D.; Al-Ghazi, M.S.A.L.; Videla, N.

    1979-10-01

    Deuteron breakup cross sections induced by 28.6 MeV protons have been measured in collinear and noncollinear geometry and the results compared with an exact three-body calculation using the Doleschall code. This calculation includes two-body interactions in S and P waves and, in addition, a tensor force. The agreement with experiment in all cases is excellent. No evidence is seen for a collinearity enhancement.

  11. Multi-pass, multi-bunch beam breakup for 9-cell Tesla cavities in the ERL

    International Nuclear Information System (INIS)

    Generally, the Energy Recovery Linac (ERL) needs specially designed high current superconducting RF cavities. In this paper, the threshold current of beam breakup for compact ERL facilities with 9-cell Tesla type cavities are investigated. The results show that it is feasible to adopt the 9-cell Tesla cavity for compact ERL test facilities with just a few cavities and beam current around 10 mA. (authors)

  12. Numerical studies of spray breakup in a gasoline direct injection (GDI) engine

    OpenAIRE

    Jafarmadar Samad; Heidarpoor Vahied

    2011-01-01

    The objective of this study is to investigate Spray Breakup process of sprays injected from single and two-hole nozzles for gasoline direct Injection (GDI) engines by using three dimensional CFD code. Spray characteristics were examined for spray tip penetration and other characteristics including: the vapor phase concentration distribution and droplet spatial distribution, which were acquired using the computational fluid dynamics (CFD) simulation. Results showed that as the hole-axis-...

  13. Hyperinflations Are Rare, but a Breakup of the Euro Area Could Prompt One

    OpenAIRE

    Anders Aslund

    2012-01-01

    Hyperinflation—usually 1,000 percent or more a year—occurs only under very special circumstances: in a disorderly breakup of a currency zone; after wars or revolutions, when monetary or fiscal authorities lack control; and when wild populism prevails. Åslund reviews the historical record and shows that hyperinflation does not arise by mistake but because of major dysfunction or mismanagement. Responsible countries with reasonable governance may default, but they do not have hyperinflation. Th...

  14. Breakup of Winter Ice Packs, Shantar Island, Sea of Okhotsk, CIS

    Science.gov (United States)

    1992-01-01

    The breakup of winter ice packs around Shantar Island (55.0N, 138.0E) off the coast of Khabarovsk Kray Oblast, CIS, produced this mosaic of icebergs, bergy bits and growlers in the Sea of Okhotsk as the as an unusual warming spell in mid winter temporarly melted parts of the sea ice. Oceanographers use these photos to study the interaction of coastal and ocean currents, tides and winds on the movement of ice floes at sea.

  15. Deformation and Break-up of Suspension Droplets Sheared in an Immiscible Fluid

    Science.gov (United States)

    Desse, Melinda; Hill, Sandra E.; Mitchell, John R.; Wolf, Bettina; Budtova, Tatiana

    2008-07-01

    The deformation and break-up behaviour of suspension droplets immersed in an immiscible fluid has not been widely studied albeit such systems are frequently encountered in every day multiphase products such as foods and cosmetics. Starch is a common thickener used in the food industry. Starch suspensions have shown to offer better flavour perception than polymer thickened solutions; a better understanding of their behaviour under flow would be beneficial in terms of advancement on product formulation. Deformation and break-up of a droplet of swollen-in-water starch granules placed in high viscosity silicon oil was visualised using a counter-rotating parallel-plate shear cell. The silicon oil had a high viscosity to induce shear stresses high enough to deform the droplet; it is also transparent and inert towards the studied system. The starch suspension was prepared to have a volume fraction of 100% swollen granules, i.e. that all water was bound within the swollen starch granules. The shear flow behaviour of this starch suspension is characterised by an apparent yield stress, shear-thinning and first normal stress differences. The rheo-optical experiments were conducted as start-up flow experiments applying shear stresses above the apparent yield stress. A constant shear stress throughout the experiment allows a constant viscosity of the droplet and therefore rules out the shear thinning aspect. Analysis showed droplet break-up at critical Capillary numbers close to those reported for Newtonian fluids. The results demonstrate that the droplet break-up behaviour in a complex emulsion system submitted to shear flow may not be fully described by the rheology of the individual phases alone but may require a microstructure component.

  16. Doomsday for the Euro Area: Causes, Variants and Consequences of Breakup

    Directory of Open Access Journals (Sweden)

    Ansgar Belke

    2012-07-01

    Full Text Available In this paper we describe the genesis of a doomsday scenario and discuss potential causes and motivations for a breakup of the euro area. For this purpose, we differentiate between the departure of weak and strong countries, and examine the impact of the reintroduction of a national currency on domestic debt, the domestic banking sector, EU membership and the freedom of trade. We also briefly analyze the social and political costs of the accompanying social disorder.

  17. Breakup of finite thickness viscous shell microbubbles by ultrasound: A simplified zero-thickness shell model

    OpenAIRE

    HSIAO, Chao-Tsung; Chahine, Georges L.

    2013-01-01

    A simplified three-dimensional (3-D) zero-thickness shell model was developed to recover the non-spherical response of thick-shelled encapsulated microbubbles subjected to ultrasound excitation. The model was validated by comparison with previously developed models and was then used to study the mechanism of bubble break-up during non-spherical deformations resulting from the presence of a nearby rigid boundary. The effects of the shell thickness and the bubble standoff distanc...

  18. Constituent particle break-up during hot rolling of AA 5182

    Energy Technology Data Exchange (ETDEWEB)

    Moulin, Nicolas; Kloecker, Helmut [Ecole des Mines de Saint-Etienne (France); Parra-Denis, Estelle; Jeulin, Dominique [Centre de Morphologie Mathematique, Mathematiques et Systemes, Mines, ParisTech, Fontainebleau (France); Ducottet, Christophe; Barat, Cecile [Laboratoire Hubert Curien, CNRS UMR 5516, Universite de Saint-Etienne (France); Bigot, Annabelle [Alcan Centre de Recherches de Voreppe (France); Boller, Elodie [ESRF, Grenoble (France); Maire, Eric [Materials Science Laboratory (MATEIS), CNRS-UMR 5510, INSA-Lyon, Villeurbanne (France)

    2010-02-15

    Aluminum sheet is currently used for body panels on a number of mass-produced vehicles, in particular for closure panels. AA5xxx alloys always contain coarse inter-metallic particles (Al{sub x}(Fe,Mn){sub y}Si, Mg{sub 2}Si) after casting. In the present work inter-metallic particle break-up during hot reversible rolling of AA5182 alloy sheets has been analyzed. The sizes and shapes of inter-metallic particles in as-cast and industrially hot rolled AA5182 alloys sheets were characterized by 3D X-ray tomography observations. The relation between particle break-up and particle morphology was then analyzed statistically and by a micromechanical finite element (FE)-based model. The essential outcomes of the statistical approach may be summarized as follows. The inter-metallic particle population may be described by five morphological parameters. Secondly the comparison of the particle morphology in as cast and industrially rolled sheets leads to the definition of five classes. The evolution of each particle class as function of the rolling strain is provided. The statistical analysis shows which particles break-up. The stresses and strains in inter-metallic particles, embedded in an elasto-viscoplastic aluminum matrix submitted to plane strain compression, were analyzed by an FE model. A new failure criterion was proposed. The essential outcomes of the mechanical approach are as follows: a precise description of stress concentration mechanisms in nonconvex particles, a close description of the parameters controlling particle break-up, and finally a simplified classification of the failure behavior. (Abstract Copyright [2010], Wiley Periodicals, Inc.)

  19. Applicability of the continuum-discretized coupled-channels method to the deuteron breakup at low energies

    CERN Document Server

    Ogata, Kazuyuki

    2016-01-01

    We re-examine the deuteron elastic breakup cross sections on 12C and 10Be at low incident energies, for which a serious discrepancy between the continuum-discretized coupled-channels method (CDCC) and the Faddeev-Alt-Grassberger-Sandhas theory (FAGS) was pointed out. We show the closed-channels neglected in the preceding study affect significantly the breakup cross section calculated with CDCC, resulting in good agreement with the result of FAGS.

  20. Curvature Singularity in the Asymmetric Breakup of an Underwater Air Bubble

    CERN Document Server

    Lai, Lipeng

    2012-01-01

    The presence of slight azimuthal asymmetry in the initial shape of an underwater bubble entirely alters the final breakup dynamics. Here I examine the influence of initial asymmetry on the final breakup by simulating the bubble surface evolution as a Hamiltonian evolution corresponding to an inviscid, two-dimensional, planar implosion. I find two types of breakups: a previously reported coalescence mode in which distant regions along the air-water surface curve inwards and eventually collide with finite speed, and a hitherto unknown cusp-like mode in which the surface develops sharp tips whose radii of curvature are much smaller than the average neck radius. I present three sets of results that characterize the nature of this cusp mode. First, I show that the cusp mode corresponds to a saddle-node. In other words, an evolution towards a cross-section shape with sharp tips invariably later evolves away from it. In phase space, this saddle-node separates coalescence modes whose coalescence planes lie along diff...

  1. Liquid jet breakup characterization with application to melt-water mixing

    International Nuclear Information System (INIS)

    Severe accidents in light-water reactors could lead to the flow of molten core material from the initial core region of the reactor vessel to the lower plenum. Steam explosions have been predicted to occur as a result of the contact of the melt with water available in the plenum. It is presently judged by many workers, that the magnitude of the energy released during such an in-vessel explosion would be insufficient to lead to failure of the containment building (SERG, 1985). A major contributing factor in this judgment is that the mass of melt which would participate in the interaction would be limited by the quantity of melt delivered to the lower plenum to the time of the explosion and by the limited breakup of the molten pour stream as it flows through the plenum prior to the explosion. Limited pour stream breakup would lead to limited melt-water mixing and, in addition, to the existence of ''large-scale'' melt masses which may lead to very inefficient thermal-to-mechanical energy conversion. The objective of this paper is to assess the available literature relevant to liquid jet breakup and to assess its implications with respect to the behavior of molten corium pour streams as they would flow from the core region through the lower plenum. Uncertainties in application of the available literature are discussed. 7 refs., 2 figs

  2. The absence of a dense potential core in supercritical injection: A thermal break-up mechanism

    Science.gov (United States)

    Banuti, Daniel T.; Hannemann, Klaus

    2016-03-01

    Certain experiments in quasi-isobaric supercritical injection remain unexplained by the current state of theory: Without developing a constant value potential core as expected from the mechanical view of break-up, density is observed to drop immediately upon entering the chamber. Furthermore, this phenomenon has never been captured in computational fluid dynamics (CFD) despite having become a de facto standard case for real fluid CFD validation. In this paper, we present strong evidence for a thermal jet disintegration mechanism (in addition to classical mechanical break-up) which resolves both the theoretical and the computational discrepancies. A new interpretation of supercritical jet disintegration is introduced, based on pseudo-boiling, a nonlinear supercritical transition from gas-like to liquid-like states. We show that thermal disintegration may dominate classical mechanical break-up when heat transfer takes place in the injector and when the fluid state is sufficiently close to the pseudo-boiling point. A procedure which allows to capture subsided cores with standard CFD is provided and demonstrated.

  3. Mesoproterozoic Earthquake Events and Breakup of the Sino-Korean Plate

    Institute of Scientific and Technical Information of China (English)

    QIAO Xiufu; GAO Linzhi; PENG Yang

    2007-01-01

    In the Mesoproterozoic time, the northern part of the Sino-Korean Plate experienced a period of intensive tectonic extension and breakup. 1. An abundance of sedimentary earthquake records is preserved in the Chuanlinggou, Tuanshanzi and Gaoyuzhuang formations in the Mesoproterozoic Changcheng System (1800-1400 Ma) and in the Mesoproterozoic Wumishan Formation of the Jixian System (1400-1000 Ma). These earthquake records are characterized by various liquefied sand-veins, carbonate microspar and coarser spar veins, limestone dikes, liquefied breccia and various forms of liquefied contorted bedding. This deformation is always associated with synsedimentary faults and igneous activity. 2. Three liquefaction models for soft carbonate sediments are recognized, including liquefaction in laminated carbonate rocks, liquefaction in thin-bedded carbonates and large-scale liquefaction along huge carbonate dikes. 3. Based on the record of earthquake and volcanic activities, the Sino-Korean Plate experienced at least twice intraplate breakups. One occurred between 1800-1400 Ma, and the other occurred at about 1200 Ma. The last breakup resulted in formation of the Yan-Liao aulacogen, a tectonic zone characterized by deeper material vibrancy, active faults, major igneous activity and frequent earthquakes.

  4. Influence of surfactant on the drop bag breakup in a continuous air jet stream

    Science.gov (United States)

    Zhao, Hui; Zhang, Wen-Bin; Xu, Jian-Liang; Li, Wei-Feng; Liu, Hai-Feng

    2016-05-01

    The deformation and breakup of surfactant-laden drops is a common phenomenon in nature and numerous practical applications. We investigate influence of surfactant on the drop bag breakup in a continuous air jet stream. The airflow would induce the advection diffusion of surfactant between interface and bulk of drop. Experiments indicate that the convective motions of deforming drop would induce the non-equilibrium distribution of surfactant, which leads to the change of surface tension. When the surfactant concentration is smaller than critical micelle concentration (CMC), with the increase of surface area of drop, the surface tension of liquid-air interface and the critical Weber number will increase. When the surfactant concentration is bigger than CMC, the micelle can be considered as the source term, which can supply the monomers. So in the presence of surfactant, there would be the significant nonlinear variation on the critical Weber number of bag breakup. We build the dynamic non-monotonic relationship between concentrations of surfactant and critical Weber number theoretically. In the range of parameters studied, the experimental results are consistent with the model estimates.

  5. Large-eddy simulation of cavitating nozzle flow and primary jet break-up

    International Nuclear Information System (INIS)

    We employ a barotropic two-phase/two-fluid model to study the primary break-up of cavitating liquid jets emanating from a rectangular nozzle, which resembles a high aspect-ratio slot flow. All components (i.e., gas, liquid, and vapor) are represented by a homogeneous mixture approach. The cavitating fluid model is based on a thermodynamic-equilibrium assumption. Compressibility of all phases enables full resolution of collapse-induced pressure wave dynamics. The thermodynamic model is embedded into an implicit large-eddy simulation (LES) environment. The considered configuration follows the general setup of a reference experiment and is a generic reproduction of a scaled-up fuel injector or control valve as found in an automotive engine. Due to the experimental conditions, it operates, however, at significantly lower pressures. LES results are compared to the experimental reference for validation. Three different operating points are studied, which differ in terms of the development of cavitation regions and the jet break-up characteristics. Observed differences between experimental and numerical data in some of the investigated cases can be caused by uncertainties in meeting nominal parameters by the experiment. The investigation reveals that three main mechanisms promote primary jet break-up: collapse-induced turbulent fluctuations near the outlet, entrainment of free gas into the nozzle, and collapse events inside the jet near the liquid-gas interface

  6. Liquid-bridge stability and breakup on surfaces with contact-angle hysteresis.

    Science.gov (United States)

    Akbari, Amir; Hill, Reghan J

    2016-08-10

    We study the stability and breakup of liquid bridges with a free contact line on surfaces with contact-angle hysteresis (CAH) under zero-gravity conditions. Non-ideal surfaces exhibit CAH because of surface imperfections, by which the constraints on three-phase contact lines are influenced. Given that interfacial instabilities are constraint-sensitive, understanding how CAH affects the stability and breakup of liquid bridges is crucial for predicting the drop size in contact-drop dispensing. Unlike ideal surfaces on which contact lines are always free irrespective of surface wettability, contact lines may undergo transitions from pinned to free and vice versa during drop deposition on non-ideal surfaces. Here, we experimentally and theoretically examine how stability and breakup are affected by CAH, highlighting cases where stability is lost during a transition from a pinned-pinned (more constrained) to pinned-free (less constrained) interface-rather than a critical state. This provides a practical means of expediting or delaying stability loss. We also demonstrate how the dynamic contact angle can control the contact-line radius following stability loss. PMID:27443494

  7. Large-eddy simulation of cavitating nozzle flow and primary jet break-up

    Energy Technology Data Exchange (ETDEWEB)

    Örley, F., E-mail: felix.oerley@aer.mw.tum.de; Trummler, T.; Mihatsch, M. S.; Schmidt, S. J.; Adams, N. A. [Institute of Aerodynamics and Fluid Mechanics, Technische Universität München, Boltzmannstr. 15, 85748 Garching bei München (Germany); Hickel, S. [Institute of Aerodynamics and Fluid Mechanics, Technische Universität München, Boltzmannstr. 15, 85748 Garching bei München (Germany); Chair of Computational Aerodynamics, Faculty of Aerospace Engineering, TU Delft, Kluyverweg 1, 2629 HS Delft (Netherlands)

    2015-08-15

    We employ a barotropic two-phase/two-fluid model to study the primary break-up of cavitating liquid jets emanating from a rectangular nozzle, which resembles a high aspect-ratio slot flow. All components (i.e., gas, liquid, and vapor) are represented by a homogeneous mixture approach. The cavitating fluid model is based on a thermodynamic-equilibrium assumption. Compressibility of all phases enables full resolution of collapse-induced pressure wave dynamics. The thermodynamic model is embedded into an implicit large-eddy simulation (LES) environment. The considered configuration follows the general setup of a reference experiment and is a generic reproduction of a scaled-up fuel injector or control valve as found in an automotive engine. Due to the experimental conditions, it operates, however, at significantly lower pressures. LES results are compared to the experimental reference for validation. Three different operating points are studied, which differ in terms of the development of cavitation regions and the jet break-up characteristics. Observed differences between experimental and numerical data in some of the investigated cases can be caused by uncertainties in meeting nominal parameters by the experiment. The investigation reveals that three main mechanisms promote primary jet break-up: collapse-induced turbulent fluctuations near the outlet, entrainment of free gas into the nozzle, and collapse events inside the jet near the liquid-gas interface.

  8. Rapid three-dimensional passive rotation micromixer using the breakup process

    Science.gov (United States)

    Park, Sung-Jin; Kim, Jung Kyung; Park, Junha; Chung, Seok; Chung, Chanil; Chang, Jun Keun

    2004-01-01

    Stretching and folding, diffusion, and breakup are three basic processes that occur while mixing fluids. Although stretching and folding the interface of two fluids by rotation enables the mixing at microscale level in both low and high Reynolds number flows, rotation is not as effective at a low Reynolds number as at a high Reynolds number. Therefore, developing a rapid micromixer for microfluidic systems that can be used at a low Reynolds number is a challenging task, because it can demonstrate the full potential of microfluidic systems in commercial markets. Here, to enhance the mixing efficiency of a micromixer based on passive rotation, we present a breakup method. The breakup method not only generates interface actively but also enhances the diffusion process at the interface. With our novel design, over 70% mixing can be achieved only after passing through a 4 mm long microchannel. In this work, the mixer was easily fabricated with polydimethylsiloxane by soft lithography and a self-aligned bonding method with methanol. We analyzed the flow in the micromixer using the computational fluid dynamics method. Also, we conducted quantitative analyses using a confocal scanning microscope and image processing.

  9. DebriSat: The New Hypervelocity Impact Test for Satellite Breakup Fragment Characterization

    Science.gov (United States)

    Cowardin, Heather

    2015-01-01

    To replicate a hyper-velocity fragmentation event using modern-day spacecraft materials and construction techniques to better improve the existing DoD and NASA breakup models: DebriSat is intended to be representative of modern LEO satellites. Major design decisions were reviewed and approved by Aerospace subject matter experts from different disciplines. DebriSat includes 7 major subsystems. Attitude determination and control system (ADCS), command and data handling (C&DH), electrical power system (EPS), payload, propulsion, telemetry tracking and command (TT&C), and thermal management. To reduce cost, most components are emulated based on existing design of flight hardware and fabricated with the same materials. center dotA key laboratory-based test, Satellite Orbital debris Characterization Impact Test (SOCIT), supporting the development of the DoD and NASA satellite breakup models was conducted at AEDC in 1992. Breakup models based on SOCIT have supported many applications and matched on-orbit events reasonably well over the years.

  10. Coarse break-up of a stream of oxide and steel melt in a water pool. Contract research

    International Nuclear Information System (INIS)

    Break-up of a melt jet in a water pool is an important phenomenon in relation to the premixing phase of steam explosions and the coolability of debris bed in severe accidents of light water reactors. A series of experiments on the break-up of high temperature oxide and steel melt jets in a water pool were conducted. The objective was to obtain data for the jet break-up length and size distribution of the droplets produced by the jet break-up, and information on the influence of material properties. Also, we tried to obtain additional information giving a clue to the mechanism governing the melt jet break-up, such as flow intensity of the steam column surrounding the melt jet, and its relation with the droplet size. In the experiments, zirconia-alumina mixture and stainless steel melt jets with diameter ∼ 17mm and velocity ∼7.8m/s at the water surface were dropped into a deep (2.1m) or shallow (0.6m) water pool with various subcool. From the results of the present experiments and also by referring other experimental data from literature, we obtained empirical correlation equations for the jet break-up length, the fraction of jet broken-up in a shallow pool where the jet was not completely broken-up, and the droplet size. (author)

  11. With or Without You? Contextualizing the Impact of Romantic Relationship Breakup on Crime Among Serious Adolescent Offenders.

    Science.gov (United States)

    Larson, Matthew; Sweeten, Gary; Piquero, Alex R

    2016-01-01

    The decline and delay of marriage has prolonged adolescence and the transition to adulthood, and consequently fostered greater romantic relationship fluidity during a stage of the life course that is pivotal for both development and offending. Yet, despite a growing literature of the consequences of romantic relationships breakup, little is known about its connection with crime, especially among youth enmeshed in the criminal justice system. This article addresses this gap by examining the effects of relationship breakup on crime among justice-involved youth-a key policy-relevant group. We refer to data from the Pathways to Desistance Study, a longitudinal study of 1354 (14% female) adjudicated youth from the juvenile and adult court systems in Phoenix and Philadelphia, to assess the nature and complexity of this association. In general, our results support prior evidence of breakup's criminogenic influence. Specifically, they suggest that relationship breakup's effect on crime is particularly acute among this at-risk sample, contingent upon post-breakup relationship transitions, and more pronounced for relationships that involve cohabitation. Our results also extend prior work by demonstrating that breakup is attenuated by changes in psychosocial characteristics and peer associations/exposure. We close with a discussion of our findings, their policy implications, and what they mean for research on relationships and crime among serious adolescent offenders moving forward. PMID:26092231

  12. Updated evidences of the Trojan Horse particle invariance for $^2$H(d,p)$^3$H reaction

    OpenAIRE

    Pizzone, R. G.; Spitaleri, C.(Dip. di Fisica e Astronomia, Univ. di Catania, via S. Sofia, Catania, Italy); Bertulani, C. A.; Mukhamedzhanov, A. M.; Blokhintsev, L.; M. La Cognata; Lamia, L; Rinollo, A.; Spartá, R.; A. Tumino

    2012-01-01

    The Trojan Horse nucleus invariance for the binary d(d,p)t reaction was tested using the quasi free $^2$H($^6$Li, pt)$^4$He and $^2$H($^3$He,pt)H reactions after $^6$Li and $^3$He break-up, respectively. The astrophysical S(E)-factor for the d(d,p)t binary process was then extracted in the framework of the Plane Wave Approximation applied to the two different break-up schemes. The obtained results are compared with direct data as well as with previous indirect investigations. The very good ag...

  13. Linking collisional and accretionary orogens during Rodinia assembly and breakup: Implications for models of supercontinent cycles

    Science.gov (United States)

    Cawood, Peter A.; Strachan, Robin A.; Pisarevsky, Sergei A.; Gladkochub, Dmitry P.; Murphy, J. Brendan

    2016-09-01

    Periodic assembly and dispersal of continental fragments has been a characteristic of the solid Earth for much of its history. Geodynamic drivers of this cyclic activity are inferred to be either top-down processes related to near surface lithospheric stresses at plate boundaries or bottom-up processes related to mantle convection and, in particular, mantle plumes, or some combination of the two. Analysis of the geological history of Rodinian crustal blocks suggests that internal rifting and breakup of the supercontinent were linked to the initiation of subduction and development of accretionary orogens around its periphery. Thus, breakup was a top-down instigated process. The locus of convergence was initially around north-eastern and northern Laurentia in the early Neoproterozoic before extending to outboard of Amazonia and Africa, including Avalonia-Cadomia, and arcs outboard of Siberia and eastern to northern Baltica in the mid-Neoproterozoic (∼760 Ma). The duration of subduction around the periphery of Rodinia coincides with the interval of lithospheric extension within the supercontinent, including the opening of the proto-Pacific at ca. 760 Ma and the commencement of rifting in east Laurentia. Final development of passive margin successions around Laurentia, Baltica and Siberia was not completed until the late Neoproterozoic to early Paleozoic (ca. 570-530 Ma), which corresponds with the termination of convergent plate interactions that gave rise to Gondwana and the consequent relocation of subduction zones to the periphery of this supercontinent. The temporal link between external subduction and internal extension suggests that breakup was initiated by a top-down process driven by accretionary tectonics along the periphery of the supercontinent. Plume-related magmatism may be present at specific times and in specific places during breakup but is not the prime driving force. Comparison of the Rodinia record of continental assembly and dispersal with that

  14. Study of the structure of unstable nuclei through the reaction experiments

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    Along with the development of the radioactive nuclear beam facility, the study of the structure of unstable nuclei has progressed rapidly over the last few decades. Due to the weakly binding property, the structure information of the unstable nuclei comes primarily from the scattering or reaction experiments. Therefore it would be very important to understand clearly the reaction mechanism involved in the experiment. We outlined here the major reaction mechanisms which are adequate to the study of unstable nuclei, with the focus on the new phenomena and methods in comparison with those with traditional stable nucleus beam. Especially emphasized are the breakup and knockout reactions, developed as accurate tools for spectroscopy investigation into the nuclear structure with low intensity secondary beam. Couplings of the breakup channel to the elastic scattering and the fusion and transfer reactions are also reviewed.

  15. Reaction dynamics for fusion of weakly-bound nuclei

    OpenAIRE

    Hagino, K.; Vitturi, A.

    2004-01-01

    We discuss several open problems of fusion reactions induced by weakly bound nuclei. For this purpose, we solve a one dimensional three-body Hamiltonian with the coupled-channels formalism. We show that the continuum-continuum couplings substantially reduce the total fusion probability at energies above the barrier compared with the no-breakup case, although the fusion probability remains enhanced at subbarrier energies. We then discuss a role of transfer process in fusion of weakly bound nuc...

  16. Study of reactions induced by 6He on 9Be

    Directory of Open Access Journals (Sweden)

    Pires K.C.C.

    2014-03-01

    Full Text Available We present the results of experiments using a 6He beam on a 9Be target at energies 7 − 9 times the Coulomb barrier. Angular distributions of the elastic, inelastic scattering (target breakup and the a-particle production in the 6He+9Be collision have been analysed. Total reaction cross sections were obtained from the elastic scatteringanalyses and a considerable enhancement has been observed by comparing to stable systems.

  17. Establishing a theory for deuteron-induced surrogate reactions

    Science.gov (United States)

    Potel, G.; Nunes, F. M.; Thompson, I. J.

    2015-09-01

    Background: Deuteron-induced reactions serve as surrogates for neutron capture into compound states. Although these reactions are of great applicability, no theoretical efforts have been invested in this direction over the last decade. Purpose: The goal of this work is to establish on firm grounds a theory for deuteron-induced neutron-capture reactions. This includes formulating elastic and inelastic breakup in a consistent manner. Method: We describe this process both in post- and prior-form distorted wave Born approximation following previous works and discuss the differences in the formulation. While the convergence issues arising in the post formulation can be overcome in the prior formulation, in this case one still needs to take into account additional terms due to nonorthogonality. Results: We apply our method to the 93Nb(d ,p )X at Ed=15 and 25 MeV and are able to obtain a good description of the data. We look at the various partial wave contributions, as well as elastic versus inelastic contributions. We also connect our formulation with transfer to neutron bound states. Conclusions: Our calculations demonstrate that the nonorthogonality term arising in the prior formulation is significant and is at the heart of the long-standing controversy between the post and the prior formulations of the theory. We also show that the cross sections for these reactions are angular-momentum dependent and therefore the commonly used Weisskopf limit is inadequate. Finally, we make important predictions for the relative contributions of elastic breakup and nonelastic breakup and call for elastic-breakup measurements to further constrain our model.

  18. Robustness and breakup of the spiral wave in a two-dimensional lattice network of neurons

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The robustness and breakup of spiral wave in a two-dimensional lattice networks of neurons are investigated. The effect of small- world type connection is often simplified with local regular connection and the long-range connection with certain probability. The network effect on the development of spiral wave can be better described by local regular connection and changeable long-range connection probability than fixed long-range connection probability because the long-range probability could be changeable in realistic biological system. The effect from the changeable probability for long-range connection is simplified by multiplicative noise. At first, a stable rotating spiral wave is developed by using appropriate initial values, parameters and no-flux boundary conditions, and then the effect of networks is investigated. Extensive numerical studies show that spiral wave keeps its alive and robust when the intensity of multiplicative noise is below a certain threshold, otherwise, the breakup of spiral wave occurs. A statistical factor of synchronization in two-dimensional array is defined to study the phase transition of spiral wave by checking the membrane potentials of all neurons corresponding to the critical parameters(the intensity of noise or forcing current)in the curve for factor of synchronization. The Hindmarsh-Rose model is investigated, the Hodgkin-Huxley neuron model in the presence of the channel noise is also studied to check the model independence of our conclusions. And it is found that breakup of spiral wave is easier to be induced by the multiplicative noise in presence of channel noise.

  19. Break-up of a non-Newtonian jet injected downwards in a Newtonian liquid

    Indian Academy of Sciences (India)

    Absar M Lakdawala; Rochish Thaokar; Atul Sharma

    2015-05-01

    The present work on downward injection of non-Newtonian jet is an extension of our recent work (Lakdawala et al, Int. J. Multiphase Flow. 59: 206–220, 2014) on upward injection of Newtonian jet. The non-Newtonian rheology of the jet is described by a Carreau type generalized Newtonian fluid (GNF) model, which is a phenomenological constitutive equation that accounts for both rate-thinning and rate-thickening. Level set method based numerical study is done for Newtonian as well as various types of shear thinning and thickening jet fluid. Effect of average injection velocity ($V_{av,i}$) is studied at a constant Reynolds number Re = 14.15, Weber number W e = 1, Froude number F r = 0.25, density ratio $\\chi$ = 0.001 and viscosity ratio $\\eta$ = 0.01. CFD analysis of the temporal variation of interface and jet length ($L_{j}$) is done to propose different types of jet breakup regimes. At smaller, intermediate and larger values of $V_{av,i}$, the regimes found are periodic uniform drop (P-UD), quasi-periodic non-uniform drop (QP-NUD) and no breakup (NB) regimes for a shear thinning jet; and periodic along with Satellite Drop (P+S), jetting (J) and no breakup (NB) regimes for a shear thickening jet, respectively. This is presented as a drop-formation regime map. Shear thickening (thinning) is shown to produce long (short) jet length. Diameter of the primary drop increases and its frequency of release decreases, due to increase in stability of the jet for shear thickening as compared to thinning fluid.

  20. Study of a clusters in 40Ca and 40Ar through nuclear break-up

    International Nuclear Information System (INIS)

    Nuclei are complex self-bound systems formed by nucleons. Conjointly to a mean-field picture in which nucleons can be regarded as independent particles, few nucleons might self-organize into compact objects, called clusters, inside the nucleus. It is theoretically predicted that it should manifest itself most strikingly for N = Z nuclei close to the emission thresholds and has been studied extensively in this region. We propose to study α-clusterization in the ground state of the N = Z 4020Ca20 nucleus and the N (different of) Z 4018Ar22 nucleus. We have studied the nuclear break-up of 40Ca when the 40Ar projectile passes by. If α clusters are preformed in 40Ca, the probability of α-emission through nuclear break-up will be enhanced as compared to 40Ar N (different of) Z nuclei.The nuclear break-up of 40Ca was studied with an 40Ar beam produced at GANIL at 35 MeV/A. The SPEG spectrometer was used to detect the heavy projectile with accurate resolution. The MUST2 Silicon detectors were placed around the target to measure the emitted α and the EXL calorimeter prototype was used to identify the γ rays from the decay of the residual 36Ar and 36S. A theoretical approach based on Time-Dependent Schroedinger Equation (TDSE) theory has been used to reproduce some experimental results like angular distributions. From the data analysis, we reconstructed excitation energy spectra and angular distributions which are compared to TDSE theory to extract some spectroscopic factors Sα. These factors show that there is no more clusterization state in the ground state of the 40Ca than in the ground state of 40Ar. (author)

  1. Constraining Lithosphere Deformation Modes during Continental Breakup for the Iberia-Newfoundland Conjugate Margins

    Science.gov (United States)

    Jeanniot, L.; Kusznir, N. J.; Mohn, G.; Manatschal, G.

    2014-12-01

    How the lithosphere and asthenosphere deforms during continental rifting leading to breakup and sea-floor spreading initiation is poorly understood. Observations at present-day and fossil analogue rifted margins show a complex OCT architecture which cannot be explained by a single simplistic lithosphere deformation modes. This OCT complexity includes hyper-extended continental crust and lithosphere, detachments faults, exhumed mantle, continental slivers and scattered embryonic oceanic crust. We use a coupled kinematic-dynamic model of lithosphere and asthenosphere deformation to determine the sequence of lithosphere deformation modes leading to continental breakup for Iberia-Newfoundland conjugate margin profiles. We quantitatively calibrate the models using observed present-day water loaded subsidence and crustal thickness, together with subsidence history and the age of melt generation. Flow fields, representing a sequence of lithosphere deformation modes, are generated by a 2D finite element viscous flow model (FE-Margin), and used to advect lithosphere and asthenosphere temperature and material. FE-Margin is kinematically driven by divergent deformation in the upper 15-20 km of the lithosphere inducing passive upwelling below. Buoyancy enhanced upwelling (Braun et al. 2000) is also kinematically included. Melt generation by decompressional melting is predicted using the methodology of Katz et al., 2003. The extension magnitudes used in the lithosphere deformation models are taken from Sutra et al (2013). The best fit calibrated models of lithosphere deformation evolution for the Iberia-Newfoundland conjugate margins require (i) an initial broad region of lithosphere deformation and passive upwelling, (ii) lateral migration of deformation, (iii) an increase in extension rate with time, (iv) focussing of deformation and (v) buoyancy induced upwelling. The preferred calibrated models predict faster extension rates and earlier continental crustal rupture and

  2. Experimental investigation of hysteresis in the break-up of liquid curtains

    KAUST Repository

    Marston, Jeremy

    2014-09-01

    Findings from an experimental investigation of the break-up of liquid curtains are reported, with the overall aim of examining stability windows for multi-layer liquid curtains composed of Newtonian fluids, where the properties of each layer can be kept constant or varied. For a single-layer curtain it is known that the minimum flow rate required for initial stability can be violated by carefully reducing the flow rate below this point, which defines a hysteresis region. However, when two or three layers are used to form a composite curtain, the hysteresis window can be considerably reduced depending on the experimental procedure used. Extensive quantitative measurements of this hysteresis region are provided alongside an examination of the influence of physical properties such as viscosity and surface tension. The origins of curtain break-up for two different geometries are analysed; first where the curtain width remains constant, pinned by straight edge guides; and second where the curtain is tapered by angled edge guides. For both cases, the rupture speed is measured, which appears to be consistent with the Taylor-Culick velocity. Observations of the typical linearly spaced jets which form after the break-up has transpired and the periodicity of these jets are compared to the Rayleigh-Taylor wavelength and previous experimental measurements. Furthermore, the curtain stability criterion originally developed by Brown (1961), summarised in terms of a Weber number, has recently been extended to multi-layer curtains by Dyson et al. (2009); thus this report provides the first experimental measurements which puts this to the test. Ultimately, it is found that only the most viscous and polymer-based liquids violate this criterion. © 2014 Elsevier Ltd.

  3. A Fragment-Cloud Approach for Modeling Atmospheric Breakup of Asteroids with Varied Internal Structures

    Science.gov (United States)

    Wheeler, Lorien; Mathias, Donovan; NASA Engineering Risk Assessment Team, NASA Asteroid Threat Assessment Project

    2016-10-01

    As an asteroid descends toward Earth, it deposits energy in the atmosphere through aerodynamic drag and ablation. Asteroid impact risk assessments rely on energy deposition estimates to predict blast overpressures and ground damage that may result from an airburst, such as the one that occurred over Chelyabinsk, Russia in 2013. The rates and altitudes at which energy is deposited along the entry trajectory depend upon how the bolide fragments, which in turn depends upon its internal structure and composition. In this work, an analytic asteroid fragmentation model has been developed to model the atmospheric breakup and resulting energy deposition of asteroids with a range of internal structures. The modeling approach combines successive fragmentation of larger independent pieces with aggregate debris clouds released with each fragmentation event. The model can vary the number and masses of fragments produced, the amount of mass released as debris clouds, and the size-strength scaling used to increase the robustness of smaller fragments. The initial asteroid body can be seeded with a distribution of independent fragment sizes amid a remaining debris mass to represent loose rubble pile conglomerations, or can be defined as a monolith with an outer regolith layer. This approach enables the model to represent a range of breakup behaviors and reproduce detailed energy deposition features such as multiple flares due to successive burst events, high-altitude regolith blow-off, or initial disruption of rubble piles followed by more energetic breakup of the constituent boulders. These capabilities provide a means to investigate sensitivities of ground damage to potential variations in asteroid structure.

  4. Solving the three-body Coulomb breakup problem using exterior complex scaling

    Energy Technology Data Exchange (ETDEWEB)

    McCurdy, C.W.; Baertschy, M.; Rescigno, T.N.

    2004-05-17

    Electron-impact ionization of the hydrogen atom is the prototypical three-body Coulomb breakup problem in quantum mechanics. The combination of subtle correlation effects and the difficult boundary conditions required to describe two electrons in the continuum have made this one of the outstanding challenges of atomic physics. A complete solution of this problem in the form of a ''reduction to computation'' of all aspects of the physics is given by the application of exterior complex scaling, a modern variant of the mathematical tool of analytic continuation of the electronic coordinates into the complex plane that was used historically to establish the formal analytic properties of the scattering matrix. This review first discusses the essential difficulties of the three-body Coulomb breakup problem in quantum mechanics. It then describes the formal basis of exterior complex scaling of electronic coordinates as well as the details of its numerical implementation using a variety of methods including finite difference, finite elements, discrete variable representations, and B-splines. Given these numerical implementations of exterior complex scaling, the scattering wave function can be generated with arbitrary accuracy on any finite volume in the space of electronic coordinates, but there remains the fundamental problem of extracting the breakup amplitudes from it. Methods are described for evaluating these amplitudes. The question of the volume-dependent overall phase that appears in the formal theory of ionization is resolved. A summary is presented of accurate results that have been obtained for the case of electron-impact ionization of hydrogen as well as a discussion of applications to the double photoionization of helium.

  5. Breakup Effect of Weakly Bound Projectile on the Barrier Distribution Around Coulomb Barrier

    Institute of Scientific and Technical Information of China (English)

    贾会明; 林承键; 张焕乔; 刘祖华; 喻宁; 杨峰; 徐新星; 贾飞; 吴振东; 张世涛

    2012-01-01

    The excitation function of quasi-elastic (QEL) scattering at a backward angle has been measured for 9^Be+208^Pb. The barrier distribution was extracted by means of the first derivative of the measured excitation function and calculated with the coupled-channel model. The present work shows that the experimental barrier distribution extracted from QEL scattering is shifted to the low energy side by 1.5 MeV as compared with the theoretical one. This energy discrepancy indicates that breakup is important in the colliding processes of the weakly bound nucleus system.

  6. Flow visualization of Taylor-mode breakup of a viscous liquid jet

    Science.gov (United States)

    Tsai, Shirley C.; Luu, Patrick; Tam, Patrick; Roski, Gerald; Tsai, Chen S.

    1999-06-01

    We recently reported a new spray technique called ultrasound-modulated two-fluid (UMTF) atomization and the pertinent "resonant liquid capillary wave (RLCW) theory" based on linear models of Taylor-mode breakup of capillary waves. In this article, flow visualizations of liquid jets near the nozzle tip are presented to verify the central assumption of the RLCW theory that the resonant liquid capillary wave in UMTF atomization is initiated by the ultrasound at the nozzle tip. Specifically, a bright band beneath the nozzle tip was seen in ultrasonic and UMTF atomization separately, but not in two-fluid atomization. The bright band can be attributed to scattering of laser light sheet by the capillary waves generated by the ultrasound on the intact liquid jet. As the capillary wave travels downstream in the direction of airflow, it is amplified by the air blowing around it and eventually collapsed into drops. Therefore, the jet breakup time can be determined by dividing the measured band length with the capillary wave velocity. The breakup times thus determined for water and glycerol/water jets are twice the values predicted by the modified Taylor's model with a sheltering parameter, and are one order of magnitude shorter than those in conventional two-fluid atomization. Furthermore, the images of the spray in the proximity of the nozzle tip obtained by 30 ns laser pulses are consistent with the drop sizes obtained 2.3-6 cm downstream from the nozzle tip by 13 s time average of continuous laser light. Also reported in this article is the good agreement between the measured viscosity effects on the drop-size and size distribution in UMTF atomization and those on the relative amplitude growth rates of capillary waves at different wavelengths predicted by Taylor's model as a result of its inclusion of higher order terms other than the first in viscosity. These new findings have led to the conclusion that UMTF atomization occurs via Taylor-mode breakup of capillary waves

  7. Comparison of axial and radial electron beam-breakup transit-time oscillators

    Energy Technology Data Exchange (ETDEWEB)

    Kwan, T.J.T. [Los Alamos National Lab., NM (United States); Mostrom, M.A. [Mission Research Corporation, Albuquerque, NM (United States)

    1995-08-01

    Comparison of two configurations of a novel high-power microwave generator is presented in this article. Coupling the beam-breakup instability with the transit-time effect of the electron beam in the cavity, rapid energy exchange between the electrons and cavity modes can occur. The dominant cavity modes in the axial and radial configurations are different but their growth rates are comparable. We found that the radial configuration can have a beam impedance less than 10 {Omega} and therefore more suitable for low-voltage and high power operation. Good agreements have been obtained between linear theory and simulation for both configurations.

  8. An Attempt to Observe Debris from the Breakup of a Titan 3C-4 Transtage

    Science.gov (United States)

    Barker, E. S.; Matney, M. J.; Yanagisawa, T.; Liou, J.-C.; Abercromby, K. J.; Rodriquez, H. M.; Horstman, M. F.; Seitzer, P.

    2007-01-01

    In February 2007 dedicated observations were made of the orbital space predicted to contain debris from the breakup of the Titan 3C-4 transtage back on February 21, 1992. These observations were carried out on the Michigan Orbital DEbris Survey Telescope (MODEST) in Chile with its 1.3deg field of view. The search region or orbital space (inclination and right ascension of the ascending node (RAAN) was predicted using NASA#s LEGEND (LEO-to-GEO Environment Debris) code to generate a Titan debris cloud. Breakup fragments are created based on the NASA Standard Breakup Model (including fragment size, area-to-mass (A/M), and delta-V distributions). Once fragments are created, they are propagated forward in time with a subroutine GEOPROP. Perturbations included in GEOPROP are those due to solar/lunar gravity, radiation pressure, and major geopotential terms. Barker, et. al, (AMOS Conference Proceedings, 2006, pp. 596-604) used similar LEGEND predictions to correlate survey observations made by MODEST (February 2002) and found several possible night-to-night correlations in the limited survey dataset. One conc lusion of the survey search was to dedicate a MODEST run to observing a GEO region predicted to contain debris fragments and actual Titan debris objects (SSN 25000, 25001 and 30000). Such a dedicated run was undertaken with MODEST between February 17 and 23, 2007 (UT dates). MODEST#s limiting magnitude of 18.0 (S\\N approx.10) corresponds to a size of 22cm assuming a diffuse Lambertian albedo of 0.2. However, based on observed break-up data, we expect most debris fragments to be smaller than 22cm which implies a need to increase the effective sensitivity of MODEST for smaller objects. MODEST#s limiting size can be lowered by increasing the exposure time (20 instead of 5 seconds) and applying special image processing. The special processing combines individual CCD images to detect faint objects that are invisible on a single CCD image. Sub-images are cropped from six

  9. Joint venture breakup and the exploration-exploitation trade-off

    OpenAIRE

    LONG, Ngo van; Soubeyran, Antoine; Soubeyran, Raphael

    2009-01-01

    This paper explores the effect of a potential joint-venture breakup on the level of technology transfer in a set-up with exploration-exploitation trade-offs in the presence of time compression costs. We consider a joint-venture relationship between a technologically advanced multinational firm and a local firm operating in a developing economy where the ability to enforce contracts is weak, and the local firm can quit without penalties. The multinational firm has to consider the advantages an...

  10. Flocculation and floc break-up related to tidally induced turbulent shear in a low-turbidity, microtidal estuary

    DEFF Research Database (Denmark)

    Markussen, Thor Nygaard; Andersen, Thorbjørn Joest

    2014-01-01

    Flocculation and floc break-up dynamics were studied in two field campaigns with calm winds in the northernmost part of the Danish Wadden Sea. The studies were carried out using a LISST-100C together with CTD-instruments and a current meter. A quasi-Lagrangian profiling method was used to assess...... flocculation and floc break-up dynamics in the lower part of the water column in the period around slack water. These dynamics were confirmed in the Eulerian deployments and were reoccurring in every tidal cycle. The dynamics were mostly governed by changes in turbulent shear. Strong microflocs with a lower...... mean threshold diameter of 50–60 μm present at high turbulent shear flocculated to form fragile macroflocs with sizes of several hundred microns and mean diameters above 80 μm around slack water periods. A hysteresis in floc break-up and flocculation was found at high water slack (HWS), as flocs formed...

  11. The study on the relationship between breakup modes and gas-liquid interfaces

    Institute of Scientific and Technical Information of China (English)

    DU Qing; LIU Ning; YIN Jun

    2008-01-01

    Based on the linear instability analysis, the study on the relationship between breakup modes and gas-liquid interfaces of a viscous annular liquid jet moving in two swirling gas streams has been car-ried out. From the numerical results of the dispersion equation, the relevancy of the breakup mode between an annular liquid jet and two liquid jets of limiting cases, namely the cylindrical liquid jet and hollow gas jet, as well as the effects of injecting factors on the instability of an annular liquid jet, is studied in detail. Considering the effects of inner and outer interface radii on the instability of the jet, it is proved that the para-sinuous mode mainly relates to the inner interface, whereas the para-varicose mode mainly relates to the outer interface. The results also indicate that all the forces produced by liquid jet have similar impacts on either the instability of para-sinuous mode or para-varicose mode due to the fact that they can affect both inner and outer gas-liquid interfaces. On the other hand, all the forces exerting only on the inner interface have more powerful effects on the instability of para-sinuous mode, and all the forces exerting only on the outer interface have more powerful effects on the insta-bility of para-varicose mode. That is to say, the effects of forces are weakened greatly when penetrating the liquid jet.

  12. Simulation of melt jet breakup and debris bed formation in water pools with IKEJET/IKEMIX

    Energy Technology Data Exchange (ETDEWEB)

    Pohlner, Georg [Institute of Nuclear Technology and Energy Systems (IKE), University of Stuttgart, Pfaffenwaldring 31, 70550 Stuttgart (Germany); Vujic, Zoran [Institute of Nuclear Technology and Energy Systems (IKE), University of Stuttgart, Pfaffenwaldring 31, 70550 Stuttgart (Germany)]. E-mail: vujic@ike.uni-stuttgart.de; Buerger, Manfred [Institute of Nuclear Technology and Energy Systems (IKE), University of Stuttgart, Pfaffenwaldring 31, 70550 Stuttgart (Germany); Lohnert, Guenter [Institute of Nuclear Technology and Energy Systems (IKE), University of Stuttgart, Pfaffenwaldring 31, 70550 Stuttgart (Germany)

    2006-10-15

    The objective of the development of the code system KESS is simulating the processes of core melting, relocation of core material to the lower head of the reactor pressure vessel (RPV) and its further heatup, modelling of fission product release and coolability of the core material. In the scope of the code development, IKEJET and IKEMIX were designed as key models for the breakup of a molten jet falling into a water pool, cooling of fragments and the formation of particulate debris beds. Calculations were performed with these codes, simulating FARO corium quenching experiments at saturated (L-28) and subcooled (L-31) conditions, as well as PREMIX experiments, e.g. PM-16. With the assumption of a reduced interfacial friction between water and steam as compared to usually applied laws, the melt breakup, energy release from the melt and pressurisation of the vessel observed in the experiments are reproduced with a reasonable accuracy. The model is further applied to reactor conditions, calculating the relocation of a mass of corium of 30 t into the lower plenum, its fragmentation and the formation of a particle bed.

  13. Dynamics of associative polymer solutions: Capillary break-up, jetting and rheology

    Science.gov (United States)

    Sharma, Vivek; Serdy, James G.; Threfall-Holmes, Phil; McKinley, Gareth H.

    2011-11-01

    Associative polymer solutions are used in extensively in the formulations for water-borne paints, food, inks, cosmetics, etc to control the rheology and processing behavior of multi-component dispersions. These complex dispersions are processed and used over a broad range of shear and extensional rates. Furthermore, the commercially relevant formulations use dilute solutions of associative polymers, which have low viscosity and short relaxation times, and hence their non-Newtonian response is not apparent in a conventional rheometer. In this talk, we explore several methods for systematically exploring the linear and nonlinear solution rheology of associative polymer dispersions, including: fractional model description of physical gelation, high frequency oscillatory tests at frequencies up to 10 kHz, microfluidic shear rheometry at deformation rates up to 1000000 /s and the influence of transient extensional rheology in the jet breakup. We show that high deformation rates can be obtained in jetting flows, and the growth and evolution of instability during jetting and break-up of these viscoelastic fluids shows the influence of both elasticity and extensibility.

  14. Cumulative beam break-up study of the spallation neutron source superconducting linac

    CERN Document Server

    Jeon, D; Krafft, G A; Yunn, B; Sundelin, R; Delayen, J; Kim, S; Doleans, M

    2002-01-01

    Beam instabilities due to High Order Modes (HOMs) are a concern to superconducting (SC) linacs such as the Spallation Neutron Source (SNS) linac. The effects of pulsed mode operation on transverse and longitudinal beam breakup instability are studied for H sup - beam in a consistent manner for the first time. Numerical simulation indicates that cumulative transverse beam breakup instabilities are not a concern in the SNS SC linac, primarily due to the heavy mass of H sup - beam and the HOM frequency spread resulting from manufacturing tolerances. As little as +-0.1 MHz HOM frequency spread stabilizes all the instabilities from both transverse HOMs, and also acts to stabilize the longitudinal HOMs. Such an assumed frequency spread of +-0.1 MHz HOM is small, and hence conservative compared with measured values of sigma=0.00109(f sub H sub O sub M -f sub 0)/f sub 0 obtained from Cornell and the Jefferson Lab Free Electron Laser cavities. However, a few cavities may hit resonance lines and generate a high heat lo...

  15. The use of the nonlinear optical loop mirror for investigations of pulse breakup in optical fibers

    Science.gov (United States)

    Kuzin, Evgeny A.; Pottiez, Olivier; Ibarra-Escamilla, Baldemar

    2011-03-01

    Pulse breakup and the formation of a bunch of solitons are the principal processes at the initial stage of the supercontinuum generation using long pulses for pumping. Most investigations use the measurement of the output spectrum to characterize the development of the supercontinuum. The extraction of an individual soliton or a group of solitons with similar parameters from the bunch can reveal details that are usually hidden when only the output spectrum is measured. Earlier we have studied the NOLM including a twisted fiber and a quarter wave retarder (QWR) in the loop. Its operation is based on the nonlinear polarization rotation effect. We showed that this NOLM is stable to changes of environmental conditions, and allows simple and predictable changes of its characteristics. In previous works we demonstrated its application for mode-locked lasers, pedestal suppression, or retrieval of a pulse shape. In this work we demonstrate that the NOLM is a viable device for the investigation of pulse breakup process and soliton formation. The operation principle is based on the fact that the NOLM has a maximum transmission for the solitons with specific durations while solitons with shorter and longer durations are strongly rejected. The duration associated with high transmission depends on the NOLM length and can also be changed by amplification of the solitons before entering the NOLM. By an appropriate choice of the NOLM parameters and the amplification of the bunch of solitons, the extraction of the solitons with selected parameters is possible.

  16. The break-up dynamics of liquid threads revealed by laser radiation pressure and optocapillarity

    Science.gov (United States)

    Petit, Julien; Robert de Saint Vincent, Matthieu; Rivière, David; Kellay, Hamid; Delville, Jean-Pierre

    2014-09-01

    We show how optocapillary stresses and optical radiation pressure effects in two-phase liquids open the way for investigating the difficult problem of liquid thread breakup at small scales when surfactants are present at the interface or when the roughness of the interface becomes significant. Using thermocapillary stresses driven by light to pinch a surfactant-laden microjet, we observe deviations from the expected visco-capillary law governed by a balance between viscosity and interfacial tension. We suggest that these deviations are due to time varying interfacial tension resulting from the surfactant depletion at the neck pinching location, and we experimentally confirm this mechanism. The second case is representative of the physics of nanojets. Considering a near critical liquid-liquid interface, where the roughness of the interfaces may be tuned, we use the radiation pressure of a laser wave to produce stable fluctuating liquid columns and study their breakup. We show how pinching crosses over from the visco-capillary to a fluctuation dominated regime and describe this new regime. These experiments exemplify how optofluidics can reveal new physics of fluids.

  17. Coulomb breakup of 22C in a four-body model

    CERN Document Server

    Pinilla, E C

    2016-01-01

    Breakup cross sections are determined for the Borromean nucleus 22C by using a four-body eikonal model, including Coulomb corrections. Bound and continuum states are constructed within a 20C + n + n three-body model in hyperspherical coordinates. We compute continuum states with the correct asymptotic behavior through the R-matrix method. For the n+ n potential, we use the Minnesota interaction. As there is no precise experimental information on 21C, we define different parameter sets for the 20C + n potentials. These parameter sets provide different scattering lengths, and resonance energies of an expected 3/2+ excited state. Then we analyze the 22C ground-state energy and rms radius, as well as E1 strength distributions and breakup cross sections. The E1 strength distribution presents an enhancement at low energies. Its amplitude is associated with the low binding energy, rather than with a three-body resonance. We show that the shape of the cross section at low energies is sensitive to the ground-state pro...

  18. Investigation and Comparison between New Satellite Impact Test Results and NASA Standard Breakup Model

    Science.gov (United States)

    Sakuraba, K.; Tsuruda, Y.; Hanada, T.; Liou, J.-C.; Akahoshi, Y.

    2007-01-01

    This paper summarizes two new satellite impact tests conducted in order to investigate on the outcome of low- and hyper-velocity impacts on two identical target satellites. The first experiment was performed at a low velocity of 1.5 km/s using a 40-gram aluminum alloy sphere, whereas the second experiment was performed at a hyper-velocity of 4.4 km/s using a 4-gram aluminum alloy sphere by two-stage light gas gun in Kyushu Institute of Technology. To date, approximately 1,500 fragments from each impact test have been collected for detailed analysis. Each piece was analyzed based on the method used in the NASA Standard Breakup Model 2000 revision. The detailed analysis will conclude: 1) the similarity in mass distribution of fragments between low and hyper-velocity impacts encourages the development of a general-purpose distribution model applicable for a wide impact velocity range, and 2) the difference in area-to-mass ratio distribution between the impact experiments and the NASA standard breakup model suggests to describe the area-to-mass ratio by a bi-normal distribution.

  19. Micro-scale extensional rheometry using hyperbolic converging/diverging channels and jet breakup.

    Science.gov (United States)

    Keshavarz, Bavand; McKinley, Gareth H

    2016-07-01

    Understanding the elongational rheology of dilute polymer solutions plays an important role in many biological and industrial applications ranging from microfluidic lab-on-a-chip diagnostics to phenomena such as fuel atomization and combustion. Making quantitative measurements of the extensional viscosity for dilute viscoelastic fluids is a long-standing challenge and it motivates developments in microfluidic fabrication techniques and high speed/strobe imaging of millifluidic capillary phenomena in order to develop new classes of instruments. In this paper, we study the elongational rheology of a family of dilute polymeric solutions in two devices: first, steady pressure-driven flow through a hyperbolic microfluidic contraction/expansion and, second, the capillary driven breakup of a thin filament formed from a small diameter jet ([Formula: see text]). The small length scale of the device allows very large deformation rates to be achieved. Our results show that in certain limits of low viscosity and elasticity, jet breakup studies offer significant advantages over the hyperbolic channel measurements despite the more complex implementation. Using our results, together with scaling estimates of the competing viscous, elastic, inertial and capillary timescales that control the dynamics, we construct a dimensionless map or nomogram summarizing the operating space for each instrument. PMID:27375824

  20. Breakup of Finite-Size Colloidal Aggregates in Turbulent Flow Investigated by Three-Dimensional (3D) Particle Tracking Velocimetry.

    Science.gov (United States)

    Saha, Debashish; Babler, Matthaus U; Holzner, Markus; Soos, Miroslav; Lüthi, Beat; Liberzon, Alex; Kinzelbach, Wolfgang

    2016-01-12

    Aggregates grown in mild shear flow are released, one at a time, into homogeneous isotropic turbulence, where their motion and intermittent breakup is recorded by three-dimensional particle tracking velocimetry (3D-PTV). The aggregates have an open structure with a fractal dimension of ∼2.2, and their size is 1.4 ± 0.4 mm, which is large, compared to the Kolmogorov length scale (η = 0.15 mm). 3D-PTV of flow tracers allows for the simultaneous measurement of aggregate trajectories and the full velocity gradient tensor along their pathlines, which enables us to access the Lagrangian stress history of individual breakup events. From this data, we found no consistent pattern that relates breakup to the local flow properties at the point of breakup. Also, the correlation between the aggregate size and both shear stress and normal stress at the location of breakage is found to be weaker, when compared with the correlation between size and drag stress. The analysis suggests that the aggregates are mostly broken due to the accumulation of the drag stress over a time lag on the order of the Kolmogorov time scale. This finding is explained by the fact that the aggregates are large, which gives their motion inertia and increases the time for stress propagation inside the aggregate. Furthermore, it is found that the scaling of the largest fragment and the accumulated stress at breakup follows an earlier established power law, i.e., dfrag ∼ σ(-0.6) obtained from laminar nozzle experiments. This indicates that, despite the large size and the different type of hydrodynamic stress, the microscopic mechanism causing breakup is consistent over a wide range of aggregate size and stress magnitude.

  1. Coulomb versus nuclear break-up of sup 1 sup 1 Be halo nucleus in a nonperturbative framework

    CERN Document Server

    Fallot, M; Lacroix, D; Chomaz, P; Margueron, J

    2002-01-01

    The sup 1 sup 1 Be break-up is calculated at 41 MeV per nucleon incident energy on different targets using a nonperturbative time-dependent quantum calculation. The evolution of the neutron halo wave function shows an emission of neutron at large angles for grazing impact parameters and at forward angles for large impact parameters. The neutron angular distribution is deduced for the different targets and compared to experimental data. We emphasize the diversity of diffraction mechanisms, in particular we discuss the interplay of the nuclear effects such as the towing mode and the Coulomb break-up. A good agreement is found with experimental data.

  2. Quasi-elastic heavy-ion transfer reactions from the coulomb barrier up to several tens MeV/u

    International Nuclear Information System (INIS)

    Quasi-elastic transfer reactions populating the continuum states will be analyzed in terms of diffractional model calculations. Optimum Q value predictions will be compared to the data. Competition with other processes such as fragmentation or break-up will be also presented

  3. Neutrino Induced 4He Break-up Reaction -- Application of the Maximum Entropy Method in Calculating Nuclear Strength Function

    CERN Document Server

    Murata, T; Sato, T; Nakamura, S X

    2016-01-01

    The maximum entropy method is examined as a new tool for solving the ill-posed inversion problem involved in the Lorentz integral transformation (LIT) method. As an example, we apply the method to the spin-dipole strength function of 4He. We show that the method can be successfully used for inversion of LIT, provided the LIT function is available with a sufficient accuracy.

  4. A Model of the Bubble Break-up in a Turbulent Flow; Modelizacion de la rotura de una Burbuja en un Flujo Turbulento

    Energy Technology Data Exchange (ETDEWEB)

    Bayod, R.; Rodriguez Rodriguez, J.; Martinez Bazan, C.

    2005-07-01

    In this report, a simplified model of the break-up of an air bubble in a turbulent water flow is proposed and analyzed numerically. According to Hinze's theory, and our experimental observations, the external flow field is assumed asymmetric and irrotational for away from the bubble. furthermore the turbulent flow-field is modelled by an asymmetric hyperbolic flow-field and the evolution of the air-water interface is calculated by the levels-set method for a wide range of Reynolds and Weber numbers. Therefore, the break-up times are obtained for super-critical weber numbers and different Reynolds numbers. Therefore, the break-up times are obtained for super-critical Weber and Reynolds numbers allows the comparison of the numeric with our experimental results. Other possible break-up mechanisms for subcritical Weber number, i. e. the break-up by resonance, are also considered. (Author) 20 refs.

  5. Nonelastic nuclear reactions induced by light ions with the BRIEFF code

    CERN Document Server

    Duarte, H

    2010-01-01

    The intranuclear cascade (INC) code BRIC has been extended to compute nonelastic reactions induced by light ions on target nuclei. In our approach the nucleons of the incident light ion move freely inside the mean potential of the ion in its center-of-mass frame while the center-of-mass of the ion obeys to equations of motion dependant on the mean nuclear+Coulomb potential of the target nucleus. After transformation of the positions and momenta of the nucleons of the ion into the target nucleus frame, the collision term between the nucleons of the target and of the ion is computed taking into account the partial or total breakup of the ion. For reactions induced by low binding energy systems like deuteron, the Coulomb breakup of the ion at the surface of the target nucleus is an important feature. Preliminary results of nucleon production in light ion induced reactions are presented and discussed.

  6. Wave packet analysis and break-up length calculations for an accelerating planar liquid jet

    International Nuclear Information System (INIS)

    This paper examines the process of transition to turbulence within an accelerating planar liquid jet. By calculating the propagation and spatial evolution of disturbance wave packets generated at a nozzle where the jet emerges, we are able to estimate break-up lengths and break-up times for different magnitudes of acceleration and different liquid to air density ratios. This study uses a basic jet velocity profile that has shear layers in both air and the liquid either side of the fluid interface. The shear layers are constructed as functions of velocity which behave in line with our CFD simulations of injecting diesel jets. The non-dimensional velocity of the jet along the jet centre-line axis is assumed to take the form V (t) = tanh(at), where the parameter a determines the magnitude of the acceleration. We compare the fully unsteady results obtained by solving the unsteady Rayleigh equation to those of a quasi-steady jet to determine when the unsteady effects are significant and whether the jet can be regarded as quasi-steady in typical operating conditions for diesel engines. For a heavy fluid injecting into a lighter fluid (density ratio ρair/ρjet = q < 1), it is found that unsteady effects are mainly significant at early injection times where the jet velocity profile is changing fastest. When the shear layers in the jet thin with time, the unsteady effects cause the growth rate of the wave packet to be smaller than the corresponding quasi-steady jet, whereas for thickening shear layers the unsteady growth rate is larger than that of the quasi-steady jet. For large accelerations (large a), the unsteady effect remains at later times but its effect on the growth rate of the wave packet decreases as the time after injection increases. As the rate of acceleration is reduced, the range of velocity values for which the jet can be considered as quasi-steady increases until eventually the whole jet can be considered quasi-steady. For a homogeneous jet (q = 1), the

  7. Application of a hybrid breakup model for the spray simulation of a multi-hole injector used for a DISI gasoline engine

    International Nuclear Information System (INIS)

    A hybrid atomization and breakup model was developed for the simulation of the fuel injection processes of multi-hole injectors for direct injection spark ignition (DISI) gasoline engines. In modeling primary breakup, a competition between the Huh–Gosman and Kelvin–Helmholtz (KH) breakup mechanisms was adopted. In addition to the two breakup mechanisms above, the Rayleigh–Taylor (RT) model was selected as a third competing mechanism in simulating secondary breakup. The hybrid model was implemented in the Star-CD software to simulate the effect of the background and injection pressures on the breakup processes of gasoline jets in a constant volume vessel, and on the mixture stratification of a wall-guided DISI gasoline engine with a newly-designed cavity in the piston. Results indicate that a higher background pressure intensifies the aerodynamically induced breakup along the tip of spray although it tends to reduce the overall breakup of spray. The spray atomization enhanced by increasing injection pressures is more pronounced at elevated background pressures. With the retard of fuel injection timing, the inhomogeneity of mixture increases in the DISI gasoline engine. Double injection with elevated second injection pressure can reduce the overall inhomogeneity of the mixture and effectively direct the mixture towards the spark plug. - Highlights: •A hybrid breakup model was developed to simulate injection process in a DISI engine. •Higher fuel injection pressure enhances breakup and evaporation at the spray tip. •Single fuel injection leads to a narrow spark timing range. •Two-stage fuel injection improves the homogeneity of the mixture. •The second injection with higher fuel pressure decreases over-rich mixture

  8. Modelling of the Bubble Size Distribution in an Aerated Stirred Tank: Theoretical and Numerical Comparison of Different Breakup Models

    Directory of Open Access Journals (Sweden)

    Kálal Zbyněk

    2014-09-01

    Full Text Available The main topic of this study is the mathematical modelling of bubble size distributions in an aerated stirred tank using the population balance method. The air-water system consisted of a fully baffled vessel with a diameter of 0.29 m, which was equipped with a six-bladed Rushton turbine. The secondary phase was introduced through a ring sparger situated under the impeller. Calculations were performed with the CFD software CFX 14.5. The turbulent quantities were predicted using the standard k-ε turbulence model. Coalescence and breakup of bubbles were modelled using the MUSIG method with 24 bubble size groups. For the bubble size distribution modelling, the breakup model by Luo and Svendsen (1996 typically has been used in the past. However, this breakup model was thoroughly reviewed and its practical applicability was questioned. Therefore, three different breakup models by Martínez-Bazán et al. (1999a, b, Lehr et al. (2002 and Alopaeus et al. (2002 were implemented in the CFD solver and applied to the system. The resulting Sauter mean diameters and local bubble size distributions were compared with experimental data.

  9. Does the association between broken partnership and first time myocardial infarction vary with time after break-up?

    DEFF Research Database (Denmark)

    Kriegbaum, Margit; Christensen, Ulla; Andersen, Per Kragh;

    2013-01-01

    Marriage is associated with lower risk of coronary heart disease, but it is unknown if the association depends on time since break-up with a partner. In this study we included both married and unmarried couples to study if the association between broken partnership (BP) and first time incident...

  10. Model Calculation of n + 6Li Reactions Below 20 MeV

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jing-Shang; HAN Yin-Lu

    2001-01-01

    Based on the unified Hauser-Feshbach and exciton model for light nuclei, the calculations of reaction cross sections and the double-differential cross sections for n + 6Li are performed. Since all of the first-particle emissions are from the compound nucleus to the discrete levels, the angular momentum coupling effect in pre-equilibrium mechanism must be taken into account. The fitting of the measured data indicates that the three-body break-up process needs to be involved, and the pre-equilibrium reaction mechanism dominates the reaction processes. In light nucleus reactions the recoil effect must be taken into account.``

  11. Vertically-Vibrated Gas-Liquid Interfaces: Surface Deformation and Breakup

    CERN Document Server

    O'Hern, T J; Brooks, C F; Shelden, B; Torczynski, J R; Kraynik, A M; Romero, L A; Benavides, G L

    2010-01-01

    In his pioneering work of 1831, Faraday demonstrated that a vertically vibrated gas-liquid interface exhibits a period-doubling bifurcation from a flat state to a wavy configuration at certain frequencies or amplitudes. Typical experiments performed using thin layers of water produce "Faraday ripples", modest-amplitude nonlinear standing waves. Later experiments by Hashimoto and Sudo (1980) and Jameson (1966) as well as those performed in the present study show that much more dramatic disturbances can be generated at the gas-liquid free surface under certain ranges of vibration conditions. This breakup mechanism was examined experimentally using deep layers of polydimethylsiloxane (PDMS) silicone oils over a range of viscosity and sinusoidal, primarily axial vibration conditions that can produce dramatic disturbances at the gas-liquid free surface. Large-amplitude vibrations produce liquid jets into the gas, droplets pinching off from the jets, gas cavities in the liquid from droplet impact, and bubble transp...

  12. Dynamics of bound vector solitons induced by stochastic perturbations: Soliton breakup and soliton switching

    International Nuclear Information System (INIS)

    We respectively investigate breakup and switching of the Manakov-typed bound vector solitons (BVSs) induced by two types of stochastic perturbations: the homogenous and nonhomogenous. Symmetry-recovering is discovered for the asymmetrical homogenous case, while soliton switching is found to relate with the perturbation amplitude and soliton coherence. Simulations show that soliton switching in the circularly-polarized light system is much weaker than that in the Manakov and linearly-polarized systems. In addition, the homogenous perturbations can enhance the soliton switching in both of the Manakov and non-integrable (linearly- and circularly-polarized) systems. Our results might be helpful in interpreting dynamics of the BVSs with stochastic noises in nonlinear optics or with stochastic quantum fluctuations in Bose–Einstein condensates.

  13. Numerical simulation of jet breakup due to amplitude-modulated (A-M) disturbance

    Institute of Scientific and Technical Information of China (English)

    LUO Jun; QI Le-hua; LI Li; YANG Fang; JIANG Xiao-shan

    2008-01-01

    In order to characterize the mechanics of jet breakup,the finite volume formulations were employed to solve the Navier-Stokes equations and continuity equation of jet.The volume of fluid (VOF) method was used to track the free surface of jet.The spray process of the molten Pb63Sn37 alloy was simulated based on the mathematical model by means of FLUENT code.The configuration of jets generated in different disturbance ratios and modulation ratios was obtained.The theoretical results show that the droplets merge together by the number of disturbance ratio N,which agrees with the corresponding picture captured in the experiment.In addition,the droplet streams broken at non-optimal frequency are also uniform according to simulation results,which proves that the A-M disturbance can increase the width of the uniform droplet generating frequency.

  14. Large area and low power dielectrowetting optical shutter with local deterministic fluid film breakup

    Science.gov (United States)

    Zhao, R.; Cumby, B.; Russell, A.; Heikenfeld, J.

    2013-11-01

    A large area (>10 cm2) and low-power (0.1-10 Hz AC voltage, ˜10's μW/cm2) dielectrowetting optical shutter requiring no pixelation is demonstrated. The device consists of 40 μm interdigitated electrodes covered by fluid splitting features and a hydrophobic fluoropolymer. When voltage is removed, the fluid splitting features initiate breakup of the fluid film into small droplets resulting in ˜80% transmission. Both the dielectrowetting and fluid splitting follow theory, allowing prediction of alternate designs and further improved performance. Advantages include scalability, optical polarization independence, high contrast ratio, fast response, and simple construction, which could be of use in switchable windows or transparent digital signage.

  15. Capillary break-up, gelation and extensional rheology of hydrophobically modified cellulose ethers

    Science.gov (United States)

    Sharma, Vivek; Haward, Simon; Pessinet, Olivia; Soderlund, Asa; Threlfall-Holmes, Phil; McKinley, Gareth

    2012-02-01

    Cellulose derivatives containing associating hydrophobic groups along their hydrophilic polysaccharide backbone are used extensively in the formulations for inks, water-borne paints, food, nasal sprays, cosmetics, insecticides, fertilizers and bio-assays to control the rheology and processing behavior of multi-component dispersions. These complex dispersions are processed and used over a broad range of shear and extensional rates. The presence of hydrophobic stickers influences the linear and nonlinear rheology of cellulose ether solutions. In this talk, we systematically contrast the difference in the shear and extensional rheology of a cellulose ether: ethy-hydroxyethyl-cellulose (EHEC) and its hydrophobically-modified analog (HMEHEC) using microfluidic shear rheometry at deformation rates up to 10^6 inverse seconds, cross-slot flow extensional rheometry and capillary break-up during jetting as a rheometric technique. Additionally, we provide a constitutive model based on fractional calculus to describe the physical gelation in HMEHEC solutions.

  16. Visual characterization of heated water spray jet breakup induced by full cone spray nozzles

    Science.gov (United States)

    Naz, M. Y.; Sulaiman, S. A.; Ariwahjoedi, B.; Zilati, K.

    2015-03-01

    The present work with specific objectives places a greater emphasis on measurements of the breakup lengths and phenomenological analysis of a hot water jet under reduced pumping pressures in still environment. Therefore, visual and comparative studies are conducted on full cone jet disintegration of heated water for low pumping pressures. A further analysis of the grabbed images confirms the strong influence of the input processing parameters on full cone spray patternation. It is also predicted that the heated liquids generate a dispersed spray pattern by utilizing partial evaporation of the spraying medium. The radial spray cone width and angle do not vary significantly with increasing Reynolds and Weber numbers at early injection phases, leading to enhanced macroscopic spray propagation. The discharge coefficient, mean flow rate, and mean flow velocity are significantly influenced by the load pressure, but less affected by the temperature. The fine scale image analysis also predicts toroidal-shaped vortex formation in the spray structure near the water boiling point.

  17. Rotating Rig Development for Droplet Deformation/Breakup and Impact Induced by Aerodynamic Surfaces

    Science.gov (United States)

    Feo, A.; Vargas, M.; Sor, A.

    2012-01-01

    This work presents the development of a Rotating Rig Facility by the Instituto Nacional de Tecnica Aeroespacial (INTA) in cooperation with the NASA Glenn Research Center. The facility is located at the INTA installations near Madrid, Spain. It has been designed to study the deformation, breakup and impact of large droplets induced by aerodynamic bodies. The importance of these physical phenomena is related to the effects of Supercooled Large Droplets in icing clouds on the impinging efficiency of the droplets on the body, that may change should these phenomena not be taken into account. The important variables and the similarity parameters that enter in this problem are presented. The facility's components are described and some possible set-ups are explained. Application examples from past experiments are presented in order to indicate the capabilities of the new facility.

  18. The effects of turbulence on droplet drag and secondary droplet breakup

    Science.gov (United States)

    Song, Y.-H.; Coy, E.; Greenfield, S.; Ondas, M.; Prevish, T.; Spegar, T.; Santavicca, D.

    1994-01-01

    The objective of this research is to obtain an improved understanding of the behavior of droplets in vaporizing sprays, particularly under conditions typical of those in high pressure rocket sprays. Experiments are conducted in a variety of high pressure, high temperature, optically-accessible flow systems, including one which is capable of operation at pressures up to 70 atm, temperatures up to 600 K, gas velocities up to 30 m/sec and turbulence intensities up to 40 percent. Single droplets, 50 to 500 micron in diameter, are produced by an aerodynamic droplet generator and transversely injected into the flow. Measurements are made of the droplet position, size, velocity and temperature and of the droplet's vapor wake from which droplet drag, dispersion, heating, vaporization and breakup are characterized.

  19. Magmatism during Gondwana break-up : new geochronological data from Westland, New Zealand

    International Nuclear Information System (INIS)

    Newly determined Late Cretaceous 40Ar/39Ar ages on megacrystic kaersutite from four lamprophyre dikes, and a U-Pb zircon age on a trachyte, from central and north Westland (New Zealand) are presented. These ages suggest that the intrusion of mafic dikes (88-86 and 69 Ma) was not necessarily restricted to the previously established narrow age range of 80-92 Ma. The younger lamprophyre and trachyte dikes (c. 68-70 Ma) imply that tensional stresses in the Western Province were either renewed at this time, or that extension and related magmatism continued during opening of the Tasman Sea. Extension-related magmatism in the region not only preceded Tasman seafloor spreading initiation (starting at c. 83 Ma, lasting to c. 53 Ma), but may have sporadically continued for up to 15 Ma after continental break-up. (author)

  20. Constraining lithosphere deformation modes during continental breakup for the Iberia-Newfoundland conjugate rifted margins

    Science.gov (United States)

    Jeanniot, Ludovic; Kusznir, Nick; Mohn, Geoffroy; Manatschal, Gianreto; Cowie, Leanne

    2016-06-01

    A kinematic model of lithosphere and asthenosphere deformation has been used to investigate lithosphere stretching and thinning modes during continental rifting leading to breakup and seafloor spreading. The model has been applied to two conjugate profiles across the Iberia-Newfoundland rifted margins and quantitatively calibrated using observed present-day water loaded subsidence and crustal thickness, together with observed mantle exhumation, subsidence and melting generation histories. The kinematic model uses an evolving prescribed flow-field to deform the lithosphere and asthenosphere leading to lithospheric breakup from which continental crustal thinning, lithosphere thermal evolution, decompression melt initiation and subsidence are predicted. We explore the sensitivity of model predictions to extension rate history, deformation migration and buoyancy induced upwelling. The best fit calibrated models of lithosphere deformation evolution for the Iberia-Newfoundland conjugate margins require; (1) an initial broad region of lithosphere deformation with passive upwelling, (2) lateral migration of deformation, (3) an increase in extension rate with time, (4) focussing of the deformation and (5) buoyancy induced upwelling. The model prediction of exhumed mantle at the Iberia-Newfoundland margins, as observed, requires a critical threshold of melting to be exceeded before melt extraction. The preferred calibrated models predict faster extension rates and earlier continental crustal separation and mantle exhumation for the Iberia Abyssal Plain-Flemish Pass conjugate margin profile than for the Galicia Bank-Flemish Cap profile to the north. The predicted N-S differences in the deformation evolution give insights into the 3D evolution of Iberia-Newfoundland margin crustal separation.

  1. The Davie Ridge: a Marginal Transform Ridge not Formed During Continental Breakup

    Science.gov (United States)

    Phethean, J. J. J.; Van Hunen, J.; McCaffrey, K. J. W.; Davies, R. J.

    2014-12-01

    The breakup of Gondwana translated Madagascar southwards relative to Africa along the Davie Fracture Zone (DFZ). This fracture zone now forms the Transform Passive Continental Margin (TPCM) from Kenya to Mozambique. The Davie Ridge (DR), a transform marginal ridge, has formed along the DFZ between 5 and 2°S and 22 and 11°S, but with little expression in-between. It has been proposed that this marginal ridge was formed by the thermal effects of a passing Mid Ocean Ridge (MOR) during the separation of Gondwana. Plate kinematic reconstructions, however, constrained by ocean magnetic anomalies, show that the MOR only passed between the north and south expressions of the DR. Therefore the positive linear gravity anomalies of the DR cannot be attributed to the effects of a passing MOR, and some other mechanism must be found to explain their formation. Interpretation of seismic reflection profiles along the DR shows that the gravity highs occur adjacent to large basin structures. In the north this correlates with a basin-bounding basement high of ~Albian age, and in the south with the rift flank uplifts of the currently active Quirimbas graben. This suggests that the northern and southern DR segments are instead shoulder uplifts resulting from two separate extensional episodes during different stress regimes. These are the Cretaceous NE-SW extension during the breakup of the south Atlantic, and the E-W extension of the Neogene-recent Afar-East Africa rift system, respectfully. The lack of deformation and DR formation along the region of the TPCM passed by the MOR suggests it has been coupled by thermal effects and/or the injection of magma.

  2. Post-breakup Basin Evolution along the South-Atlantic Margins in Brazil and Angola/Namibia

    Science.gov (United States)

    Kukla, P. A.; Strozyk, F.; Back, S.

    2013-12-01

    The post-breakup tectono-stratigraphic evolution of large offshore basins along the South American and African continental margins record strongly varying post-rift sedimentary successions. The northernmost segment of the South Atlantic rift and salt basins is characterized by a pronounced asymmetry, with the Brazilian margin comprising narrower and deeper rift basins with less salt in comparison to the Congo-Gabon conjugate margin. Another important observation is that multiple phases of uplift and subsidence are recorded after the break-up of the southern South Atlantic on both sides of the Florianopolis-Walvis Ridge volcanic complex, features that are regarded as atypical when compared to published examples of other post-breakup margin successions. A regional comparison based on tectonic-stratigraphic analysis of selected seismic transects between the large basins offshore southern Brazil (Espirito Santo Basin, Campos Basin, Santos Basin, Pelotas Basin) and southwest Africa (Lower Congo Basin, Kwanza Basin, Namibe Basin, Walvis Basin) provides a comprehensive basin-to-basin documentation of the key geological parameters controlling ocean and continental margin development. This comparison includes the margin configuration, subsidence development through time, sediment influx and storage patterns, type of basin fill (e.g. salt vs. non-salt systems; carbonate-rich vs. clastics-dominated systems) and finally major tectonic and magmatic events. Data from the salt basins indicate that salt-related tectonic deformation is amongst the prime controls for the non-uniform post-rift margin development. The diversity in the stratigraphic architecture of the conjugate margins offshore southern Brazil, Namibia and Angola reflects variations in the interplay of a number of controlling factors, of which the most important are (a) the structural configuration of each margin segment at the time of break-up, (b) the post break-up subsidence history of the respective margin segment

  3. Capture cross-section and rate of the 14C(, )15C reaction from the Coulomb dissociation of 15C

    Indian Academy of Sciences (India)

    Shubhchintak; Neelam; R Chatterjee

    2014-10-01

    We calculate the Coulomb dissociation of 15C on a Pb target at 68 MeV/u incident beam energy within the fully quantum mechanical distorted wave Born approximation formalism of breakup reactions. The capture cross-section and the subsequent rate of the 14C(, )15C reaction are calculated from the photodisintegration of 15C, using the principle of detailed balance. Our theoretical model is free from the uncertainties associated with the multipole strength distributions of the projectile.

  4. Experiment E89-044 on the Quasielastic 3He(e,e'p) Reaction at Jefferson Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    E. Penel-Nottaris

    2004-07-07

    The Jefferson Lab Hall A E89-044 experiment has measured the 3He(e,e'p) reaction cross-sections. The extraction of the longitudinal and transverse response functions for the two-body break-up 3He(e,e'p)d reaction in parallel kinematics allows the study of the bound proton electromagnetic properties inside the 3He nucleus and the involved nuclear mechanisms beyond plane wave approximations.

  5. Systematic study of three-nucleon force effects in the cross section of the deuteron-proton breakup at 130 MeV

    CERN Document Server

    Kistryn, S; Bodek, K; Deltuva, A; Epelbaum, E; Ermisch, K; Glöckle, W; Golak, J; Kalantar-Nayestanaki, N; Kamada, H; Kis, M; Klos, B; Kozela, A; Kuros-Zolnierczuk, J; Mahjour-Shafiei, M; Meißner, Ulf G; Micherdzinska, A; Nogga, A; Sauer, P U; Skibinski, R; Stephan, E; Sworst, R; Witala, H; Zejma, J; Zipper, W

    2005-01-01

    High precision cross-section data of the deuteron-proton breakup reaction at 130 MeV are presented for 72 kinematically complete configurations. The data cover a large region of the available phase space, divided into a systematic grid of kinematical variables. They are compared with theoretical predictions, in which the full dynamics of the three-nucleon (3N) system is obtained in three different ways: realistic nucleon-nucleon (NN) potentials are combined with model 3N forces (3NF's) or with an effective 3NF resulting from explicit treatment of the Delta-isobar excitation. Alternatively, the chiral perturbation theory approach is used at the next-to-next-to-leading order with all relevant NN and 3N contributions taken into account. The generated dynamics is then applied to calculate cross-section values by rigorous solution of the 3N Faddeev equations. The comparison of the calculated cross sections with the experimental data shows a clear prefernce for the predictions in which the 3NF's are included. The m...

  6. Elastic scattering and fusion cross-sections in 7Li + 27Al reaction

    Indian Academy of Sciences (India)

    D Patel; S Santra; S Mukherjee; B K Nayak; P K Rath; V V Parkar; R K Choudhury

    2013-10-01

    With an aim to understand the effects of breakup and transfer channels on elastic scattering and fusion cross-sections in the 7Li + 27Al reaction, simultaneous measurement of elastic scattering angular distributions and fusion cross-sections have been carried out at various energies (lab = 8.0–16.0 MeV) around the Coulomb barrier. Optical model (OM) analysis of the elastic scattering data does not show any threshold anomaly or breakup threshold anomaly behaviour in the energy dependence of the real and imaginary parts of the OM potential. Fusion cross-section at each bombarding energy is extracted from the measured -particle evaporation energy spectra at backward angles by comparing with the statistical model prediction. Results on fusion cross-sections from the present measurements along with data from the literature have been compared with the coupled-channels predictions. Detailed coupled-channels calculations have been carried out to study the effect of coupling of breakup, inelastic and transfer, channels on elastic scattering and fusion. The effect of 1-stripping transfer coupling was found to be significant compared to that of the projectile breakup couplings in the present system.

  7. An Experimental Study on the Breakup of Simulant Melt Jet Released from the Submerged Reactor Vessel Lower Head

    International Nuclear Information System (INIS)

    The potential risk of explosive molten fuel coolant interactions (FCI, steam explosion) has drawn substantial attention in the safety analysis of reactor severe accidents. The steam explosion intensity is largely dependent upon the degree of volumetric fractions of melt droplets and steam in the fuel-coolant mixture. The rate of melt jet breakup and droplet sizes are, therefore, the key physical parameters in the analysis of FCIs. An ex-vessel steam explosion may occur when the core melt is released from the failed reactor vessel lower head into the water-filled reactor cavity. The water level in the cavity can be either below or above the reactor vessel lower head depending on the severe accident management strategy. The former, a partially-filled cavity with free-fall space for the melt jet, has been the major condition for the steam explosion studies in the past. An In-Vessel Retention by External Vessel Cooling (IVR-ERVC), however, requires the water level in the cavity be above the reactor vessel lower head so that the vessel can be completely submerged in coolant water. In this case, the melt jet falls in liquid water without free fall. The jet breakup behavior in such a condition has been rarely studied, nor well identified. In this work, jet breakup of the melt released from the submerged vessel has been experimentally investigated using stimulant melt of Woods metal. The initial melt temperature was set below the boiling point of water so that only the hydrodynamic mechanism of jet breakup can be identified. High-speed videos were taken to visualize the jet breakup behavior and the post-test debris were collected and sieved to obtain debris size distributions. Non-boiling liquid jet breakup experiment was conducted using 50 mm-diameter Woods metal jet released from a vessel submerged in water pool. The post-test debris was sieved and the debris size distributions were obtained. The size of the largest mass of the debris shows a fair agreement with the

  8. Causes and consequences of continental breakup in the South Atlantic: lessons learned from the SAMPLE program

    Science.gov (United States)

    Trumbull, Robert B.

    2014-05-01

    Since 2009 the SAMPLE program (www.spp-sample.de) provides a platform for research into the causes and effects of continental breakup and the evolution of passive margins. SAMPLE encompasses 28 projects from 13 German institutions and many international partnerships. The 6-year program will run through 2015. At the core of the program are observational studies that are interlinked by modelling projects examining the interplay of deep mantle dynamics, lithospheric stress fields, pre-rift fabric and melt-weaking on localizing rifting. Geophysics teams collect and integrate existing data from wide-angle seismic profiles, reprocessed multichannel seismics, as well as gravity, magnetics and heat-flow studies to construct self-consistent lithospheric-scale 3-D models along the conjugate margins. Key interests are variations in margin architecture, distribution of magmatic features and the evolution of sedimentary basins (subsidence and thermal histories). An exciting new contribution of SAMPLE geophysics is a linked set of seismic, seismologic and magnetotelluric experiments along the Walvis Ridge, including onshore NW Namibia and the Tristan da Cunha hotspot. In the deep mantle, we examine evidence from global seismic tomography for dramatic low seismic-velocity regions near the core-mantle boundary beneath southern Africa and their implications for dynamics in the deep Earth and the thermo-chemical nature of plumes. Petrologic studies focus on near-primary mantle melts represented by Mg-rich mafic dikes. Projects address the origin of magmas and crust-mantle interaction, and the environmental impact of mega-scale volcanism during breakup. Thermobarometry results from the African margin reveal a N-to-S decrease in mantle potential temperatures from 1520°C (N) to 1380° (S), which supports a thermal plume origin for excessive melt production in the north. Thermochronology data from both conjugate margins reveal complex and puzzling patterns in the denudation history

  9. Reaction mechanisms in collisions induced by 8B beam close to the barrier

    CERN Multimedia

    The aim of the proposed experiment is to investigate on the reaction dynamics of proton-halo induced collisions at energies around the Coulomb barrier where coupling to continuum effects are expected to be important. We propose to measure $^{8}$B+$^{64}$Zn elastic scattering angular distribution together with the measurement, for the first time, of p-$^{7}$Be coincidences coming from transfer and/or break-up of $^{8}$B. The latter will allow a better understanding of the relative contribution of elastic $\\textit{vs}$ non-elastic break-up in reactions induced by extremely weakly-bound nuclei. We believe that with the availability of the post accelerated $^{8}$B beam at REX-ISOLDE we will be able to collect for the first time high quality data for the study of such an important topic.

  10. The Trojan-Horse Method applied to the {sup 6}Li(p,{alpha}){sup 3}He reaction down to astrophysical energies

    Energy Technology Data Exchange (ETDEWEB)

    Tumino, A.; Spitaleri, C.; Pappalardo, L.; Cherubini, S.; Del Zoppo, A.; La Cognata, M.; Musumarra, A.; Pellegriti, M.G.; Pizzone, R.G.; Rinollo, A.; Romano, S.; Typel, S

    2004-04-05

    The Trojan-Horse Method has been applied to the three-body d({sup 6}Li,{alpha}{sup 3}He)n break-up reaction in order to extract the bare nucleus S(E) factor for the {sup 6}Li(p,{alpha}){sup 3}He down to astrophysical energies.

  11. High-speed monodisperse droplet generation by ultrasonically controlled micro-jet breakup

    Science.gov (United States)

    Frommhold, Philipp Erhard; Lippert, Alexander; Holsteyns, Frank Ludwig; Mettin, Robert

    2014-04-01

    A liquid jet that is ejected from a nozzle into air will disintegrate into drops via the well-known Plateau-Rayleigh instability within a certain range of Ohnesorge and Reynolds numbers. With the focus on the micrometer scale, we investigate the control of this process by superimposing a suitable ultrasonic signal, which causes the jet to break up into a very precise train of monodisperse droplets. The jet leaves a pressurized container of liquid via a small orifice of about 20 μm diameter. The break-up process and the emerging droplets are recorded via high-speed imaging. An extended parameter study of exit speed and ultrasonic frequency is carried out for deionized water to evaluate the jet's state and the subsequent generation of monodisperse droplets. Maximum exit velocities obtained reach almost 120 m s-1, and frequencies have been applied up to 1.8 MHz. Functionality of the method is confirmed for five additional liquids for moderate jet velocities 38 m s-1. For the uncontrolled jet disintegration, the drop size spectra revealed broad distributions and downstream drop growth by collision, while the acoustic control generated monodisperse droplets with a standard deviation less than 0.5 %. By adjustment of the acoustic excitation frequency, drop diameters could be tuned continuously from about 30 to 50 μm for all exit speeds. Good agreement to former experiments and theoretical approaches is found for the relation of overpressure and jet exit speed, and for the observed stability regions of monodisperse droplet generation in the parameter plane of jet speed and acoustic excitation frequency. Fitting of two free parameters of the general theory to the liquids and nozzles used is found to yield an even higher precision. Furthermore, the high-velocity instability limit of regular jet breakup described by von Ohnesorge has been superseded by more than a factor of two without entering the wind-induced instability regime, and monodisperse droplet generation was

  12. Resonance model for the three-body states of the A=6 reactions

    Directory of Open Access Journals (Sweden)

    Paris Mark W.

    2016-01-01

    Full Text Available We present an R-matrix-based model for three-body final states that has aspects of the Faddeev approach to three-particle scattering. The model is applied to describing the nucleon spectra for breakup reactions in the A = 6 systems. Calculations using a charge-symmetric parametrization agree fairly well with the experimental data, although they indicate larger contributions from the 5He or 5Li ground state are necessary.

  13. The 2H(e, e' p)n reaction at large energy transfers

    NARCIS (Netherlands)

    Willering, Hendrik Willem

    2003-01-01

    At the ELSA accelerator facillity in Bonn, Germany, we have measured the deutron "breakup" reaction 2H(e,e' p)n at four-momentum transfers around Q2 = -0 .20(GeV/c)2 with an electron beam energy of E0 = 1.6 GeV. The cross section has been determined for energy transfers extending from the quasielast

  14. Containment scaling: experimental investigation of the break-up of a stratified layer due to a vertical jet from below

    International Nuclear Information System (INIS)

    In the context of containment safety, the break-up of a helium (helium as substitute for hydrogen) layer due to an upward vertical jet in a confined volume was the subject of experimental investigation in two geometrically similar test facilities scaled 1:4. The high instrumentation resolution in space and time of the small-scale facility (MiniPanda) provided 2D temperature field and 1D helium concentration profile measurements well suited for CFD validation and detailed analysis of the break-up process. In order to conduct similar experiments on the scaled facilities, the boundary conditions (i.e., the jet diameter and velocity) for the experiments with two length scales have been scaled with regard to a Froude number relating the jet’s buoyancy to the jets inertia at the helium layer interface. The different flow phenomena observed in the two facilities are discussed based on experimental results. (author)

  15. Emergence of spatiotemporal chaos arising from far-field breakup of spiral waves in the plankton ecological systems

    Institute of Scientific and Technical Information of China (English)

    Liu Quan-Xing; Sun Gui-Quan; Jin Zhen; Li Bai-Lian

    2009-01-01

    It has been reported that the minimal spatially extended phytoplankton-zooplankton system exhibits both tem-poral regular/chaotic behaviour, and spatiotemporal chaos in a patchy environment. As a further investigation by means of computer simulations and theoretical analysis, in this paper we observe that the spiral waves may exist and the spatiotcmporal chaos emerge when the parameters are within the mixed Turing Hopf bifurcation region, which arises from the far-field breakup of the spiral waves over a large range of diffusion coefficients of phytoplankton and zooplankton. Moreover, the spatiotemporal chaos arising from the far-field breakup of spiral waves does not gradually invade the whole space of that region. Our results arc confirmed by nonlinear bifurcation of wave trains. We also discuss ecological implications of these spatially structured patterns.

  16. Influence of projectile breakup in the elastic scattering of the systems 6,7Li+80Se

    Directory of Open Access Journals (Sweden)

    Cardona M.A.

    2011-10-01

    Full Text Available In order to study the influence of the breakup channel in the elastic scattering of the 6,7Li+80Se systems, we have measured angular distributions at center- of-mass energies from 13 ≤ Ec.m. ≤ 24 MeV (0.8VCB up to 1.6VCB . They were analyzed within the framework of the optical model to study the energy dependence of the real and imaginary parts of the nuclear potential. The focus was to investigate the threshold anomaly in those weakly bound systems. The behavior of the calculated potentials as a function of energy indicates that our results are consistent with the dispersion relation. The threshold anomaly was observed in the 7Li+80Se system and the breakup threshold anomaly was confirmed for the 6Li+80Se system.

  17. Sea spray production by bag breakup mode of fragmentation of the air-water interface at strong and hurricane wind

    Science.gov (United States)

    Troitskaya, Yuliya; Kandaurov, Alexander; Ermakova, Olga; Kozlov, Dmitry; Sergeev, Daniil; Zilitinkevich, Sergej

    2016-04-01

    Sea sprays is a typical element of the marine atmospheric boundary layer (MABL) of large importance for marine meteorology, atmospheric chemistry and climate studies. They are considered as a crucial factor in the development of hurricanes and severe extratropical storms, since they can significantly enhance exchange of mass, heat and momentum between the ocean and the atmosphere. This exchange is directly provided by spume droplets with the sizes from 10 microns to a few millimeters mechanically torn off the crests of a breaking waves and fall down to the ocean due to gravity. The fluxes associated with the spray are determined by the rate of droplet production at the surface quantified by the sea spray generation function (SSGF), defined as the number of spray particles of radius r produced from the unit area of water surface in unit time. However, the mechanism of spume droplets' formation is unknown and empirical estimates of SSGF varied over six orders of magnitude; therefore, the production rate of large sea spray droplets is not adequately described and there are significant uncertainties in estimations of exchange processes in hurricanes. Experimental core of our work comprise laboratory experiments employing high-speed video-filming, which have made it possible to disclose how water surface looks like at extremely strong winds and how exactly droplets are torn off wave crests. We classified events responsible for spume droplet, including bursting of submerged bubbles, generation and breakup of "projections" or liquid filaments (Koa, 1981) and "bag breakup", namely, inflating and consequent blowing of short-lived, sail-like pieces of the water-surface film, "bags". The process is similar to "bag-breakup" mode of fragmentation of liquid droplets and jets in gaseous flows. Basing on statistical analysis of results of these experiments we show that the main mechanism of spray-generation is attributed to "bag-breakup mechanism On the base of general principles

  18. Experimental Study of Drop Deformation and Breakup in Simple Shear Flows%简单剪切流动中液滴断裂机理

    Institute of Scientific and Technical Information of China (English)

    林长志; 郭烈锦

    2007-01-01

    The experimental results of the deformation and breakup of a single drop immersed in a Newtonian liquid and subjected to a constant shear rate which generated by counter rotating Couette apparatus were presented in this paper. From experimental observations, the breakup occurred by three mechanisms, namely, necking, end pinching, and capillary instability. Quantitative results for the deformation and breakup of drop are presented. The maximum diameter and Sauter mean diameter of daughter drops and capillary thread radius are linearly related to the inverse shear rate and independent of the initial drop size, the dimensionless wavelength which is the wavelength divided by the thread width at breakup is independent of the shear rate and initial drop size, and the deformation of threads follows a pseudo-affine deformation for Cai/Cac larger than 2.

  19. In vitro performance testing of the novel Medspray wet aerosol inhaler based on the principle of Rayleigh break-up

    NARCIS (Netherlands)

    de Boer, Anne H; Wissink, Jeroen; Hagedoorn, Paul; Heskamp, Iwan; de Kruijf, Wilbur; Bünder, Ralf; Zanen, Pieter; Munnik, Paul; van Rijn, Cees; Frijlink, Henderik W

    2008-01-01

    Purpose: A new inhaler (Medspray(R)) for pulmonary drug delivery based on the principle of Rayleigh break-up has been tested with three different spray nozzles (1.5; 2.0 and 2.5 mu m) using aqueous 0.1% (w/w) salbutamol and 0.9% (w/w) sodium chloride solutions. Materials and methods: Particle size d

  20. Modeling corium jet breakup in water pool and application to ex-vessel fuel–coolant interaction analyses

    International Nuclear Information System (INIS)

    Highlights: • Kelvin–Helmholtz Instability on melt–steam–water interfaces was solved numerically. • Corium jet breakup model was developed for FCI codes based on the KHI solutions. • Ex-vessel steam explosions in reactor cavity were calculated using TRACER-II code. - Abstract: In light water reactor core melt accidents, the molten fuel can be brought into contact with coolant water in the course of the melt relocation in-vessel and ex-vessel as well as in an accident mitigation action of water addition. For the last several decades, the potential risk of energetic molten fuel coolant interactions (FCIs, steam explosions) has drawn substantial attention in the safety analysis of reactor severe accidents. In this paper, an improved melt jet breakup model is presented and analyses of an energetic fuel–coolant interaction in a PWR cavity (1) partially filled (4 m deep) and (2) completely filled (7 m deep) with water are presented. The TRACER-II code was used in the analyses. For jet breakup model, the full dispersion equation of Kelvin–Helmholtz instability for the melt jet–vapor film–water was solved numerically and the solutions were correlated for use in the TRACER-II code. The new jet breakup model was benchmarked using FARO L28 test data. In reactor calculations the mixing calculations showed that the average melt drop size was much smaller in 4 m deep pool with 3 m free-fall than in 7 m deep pool. The explosion calculations showed that the peak pressure at the center of mixture was ∼90 MPa in 4 m deep pool, ∼25 MPa in 7 m deep pool. It also showed that the maximum impulse at the cavity wall was found at the lower wall in both cases and it was 50 kPa s in 4 m deep pool and 150 kPa s in 7 m deep pool

  1. Modeling corium jet breakup in water pool and application to ex-vessel fuel–coolant interaction analyses

    Energy Technology Data Exchange (ETDEWEB)

    Bang, Kwang-Hyun, E-mail: khbang@hhu.ac.kr; Kumar, Rohit; Kim, Hyoung-Tak

    2014-09-15

    Highlights: • Kelvin–Helmholtz Instability on melt–steam–water interfaces was solved numerically. • Corium jet breakup model was developed for FCI codes based on the KHI solutions. • Ex-vessel steam explosions in reactor cavity were calculated using TRACER-II code. - Abstract: In light water reactor core melt accidents, the molten fuel can be brought into contact with coolant water in the course of the melt relocation in-vessel and ex-vessel as well as in an accident mitigation action of water addition. For the last several decades, the potential risk of energetic molten fuel coolant interactions (FCIs, steam explosions) has drawn substantial attention in the safety analysis of reactor severe accidents. In this paper, an improved melt jet breakup model is presented and analyses of an energetic fuel–coolant interaction in a PWR cavity (1) partially filled (4 m deep) and (2) completely filled (7 m deep) with water are presented. The TRACER-II code was used in the analyses. For jet breakup model, the full dispersion equation of Kelvin–Helmholtz instability for the melt jet–vapor film–water was solved numerically and the solutions were correlated for use in the TRACER-II code. The new jet breakup model was benchmarked using FARO L28 test data. In reactor calculations the mixing calculations showed that the average melt drop size was much smaller in 4 m deep pool with 3 m free-fall than in 7 m deep pool. The explosion calculations showed that the peak pressure at the center of mixture was ∼90 MPa in 4 m deep pool, ∼25 MPa in 7 m deep pool. It also showed that the maximum impulse at the cavity wall was found at the lower wall in both cases and it was 50 kPa s in 4 m deep pool and 150 kPa s in 7 m deep pool.

  2. Measurement of pulse amplitude and phase distortion in a semiconductor optical amplifier: from pulse compression to breakup

    DEFF Research Database (Denmark)

    Romstad, Francis Pascal; Borri, Paola; Langbein, Wolfgang Werner;

    2000-01-01

    We have performed extensive measurements of the propagation of ultrashort pulses in a semiconductor bulk amplifier using an ultrasensitive cross frequency-resolved optical gating technique. Pulses of 175-fs duration with energies from below 1 fJ to above 100 pJ are measured both in amplitude...... is biased for material transparency or absorption and to a pronounced pulse breakup in the gain regime....

  3. Lithospheric controls on melt production during continental breakup at slow rates of extension: Application to the North Atlantic

    OpenAIRE

    Armitage, J.J.; Henstock, T. J.; Minshull, T.A.; Hopper, J. R.

    2009-01-01

    Rifted margins form from extension and breakup of the continental lithosphere. If this extension is coeval with a region of hotter lithosphere, then it is generally assumed that a volcanic margin would follow. Here we present the results of numerical simulations of rift margin evolution by extending continental lithosphere above a thermal anomaly. We find that unless the lithosphere is thinned prior to the arrival of the thermal anomaly or half spreading rates are more than ...

  4. Breakup process of cylindrical viscous liquid specimens after a strong explosion in the core

    Science.gov (United States)

    Bang, B. H.; Ahn, C. S.; Kim, D. Y.; Lee, J. G.; Kim, H. M.; Jeong, J. T.; Yoon, W. S.; Al-Deyab, S. S.; Yoo, J. H.; Yoon, S. S.; Yarin, A. L.

    2016-09-01

    Basic understanding and theoretical description of the expansion and breakup of cylindrical specimens of Newtonian viscous liquid after an explosion of an explosive material in the core are aimed in this work along with the experimental investigation of the discovered phenomena. The unperturbed motion is considered first, and then supplemented by the perturbation growth pattern in the linear approximation. It is shown that a special non-trivial case of the Rayleigh-Taylor instability sets in being triggered by the gas pressure differential between the inner and outer surfaces of the specimens. The spectrum of the growing perturbation waves is established, as well as the growth rate found, and the debris sizes evaluated. An experimental study is undertaken and both the numerical and analytical solutions developed are compared with the experimental data. A good agreement between the theory and experiment is revealed. It is shown that the debris size λ, the parameter most important practically, scales with the explosion energy E as λ ˜ E-1/2. Another practically important parameter, the number of fingers N measured in the experiments was within 6%-9% from the values predicted numerically. Moreover, N in the experiments and numerical predictions followed the scaling law predicted theoretically, N ˜ me 1 / 2 , with me being the explosive mass.

  5. Annual report of IGCP Project No.440 in 2003--Rodinia assembly and breakup

    Institute of Scientific and Technical Information of China (English)

    Sergei Pisarevsky

    2004-01-01

    With the latest information on geology, isotop chronology, geochemistry and aerial geophysics, the structural enviroment, geological event characterists and evolution history of component units of Rodinia Supercontinent on a global scale are discussed. And some neo views and genetic pattern are provided. The East Eurppean Cratorn had a complex evolution history between 1.7 and 0.9 Ga. The arthors propose a new reconstruction of Laurentia acient land and Siberia at ca. 1 050~1 000 Ma. The largest litho-structural record ofthe Meso-Neoproterozoic orogenic collage in South America made up the western border of the South American Platform African Cratons are the result of convergence of Paleoproterozoic/Archaem Cratonic blocks. A part of Eastern Antarctica attached to southern Africa in Mesoproterozoic.Neoproterozoic felsic magmatic events in New India made the western border of Rodinia Pre-Grevoillian Laurentia was established as a major continental block by the end of the Paleoproterozoic. South China is geologically plausible to be between southern Laurentia and eastem Australia. Yangzi-Tarim connection or neighborhood is proposed. According to the abovementionded, the assembly and breakup paattern of Rodinia proposed by Pisarevsky is tested. It telles that primary break up is along the western border of Laurentia ancient land, which is similar to northem Atlantic. Another characteristic is that some continents are not considered as component parts of Rodinia, eg. India, Congo and San-Francisco.

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

    Science.gov (United States)

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

    2014-11-01

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

  7. Numerical studies of spray breakup in a gasoline direct injection (GDI engine

    Directory of Open Access Journals (Sweden)

    Jafarmadar Samad

    2011-01-01

    Full Text Available The objective of this study is to investigate Spray Breakup process of sprays injected from single and two-hole nozzles for gasoline direct Injection (GDI engines by using three dimensional CFD code. Spray characteristics were examined for spray tip penetration and other characteristics including: the vapor phase concentration distribution and droplet spatial distribution, which were acquired using the computational fluid dynamics (CFD simulation. Results showed that as the hole-axis-angle (γ of the two-hole nozzle decreased, the droplet coalescence increased and vapor mass decreased. The spray with cone angle (θ0 5 deg for single hole nozzle has the longest spray tip penetration and the spray with the γ of 30 deg and spray cone angle θ0=30 deg for two hole nozzles had the shortest one. Also, when the spray cone angle (θ0 and hole-axis-angle (γ increased from 5 to 30 deg, the Sauter mean diameter (SMD decreased for both single-hole and two-hole nozzles used in this study. For a single-hole nozzle, when spray cone angle increased from 5 to 30 deg, the vaporization rate very much because of low level of coalescence. The result of model for tip penetration is good agreement with the corresponding experimental data in the literatures.

  8. Coherent soliton propagation through doped optical fibers: cloning, breakup, and soliton interactions

    Directory of Open Access Journals (Sweden)

    SOLANGE B. CAVALCANTI

    2001-06-01

    Full Text Available The simultaneous propagation of two optical pulses through a doped nonlinear dispersive medium modelled by a resonant three-level system was investigated numerically, within the framework of a pair of coupled extended nonlinear Schrödinger equations. These included the contribution of the dopant resonances whose dynamics is governed by Bloch equations. In this work, we review the interesting possibilities on the manipulation of fields such as cloning, breakup and soliton interactions, that the combination of coherent population trapping with nonlinear dispersive media offers.Investiga-se numericamente a propagação simultânea de dois pulsos ópticos através de um meio dispersivo não linear dopado, modelado por um sistema ressonante de três níveis, usando-se uma abordagem de equações generalizadas não lineares de Schrödinger. Estas últimas incluem a contribuição das ressonâncias do dopante cuja dinâmica é regida pelas equações de Bloch. Neste trabalho, revemos as possibilidades interessantes que a combinação de efeitos dispersivos não lineares com o aprisionamento coerente da população oferecem, tais como: clonagem, quebra e interação entre solitons.

  9. The Autumn of break-ups: When Jakobshavn Isbrae lost its floating tongue

    Science.gov (United States)

    Aschwanden, A.; Fahnestock, M. A.; Truffer, M.; Motyka, R. J.

    2015-12-01

    Capturing the temporal variability in outlet glacier flow remains one of the holy grails in ice sheet modeling. Here we demonstrate progress using the three-dimensional Parallel Ice Sheet Model. Using a first-order calving law and prescribed subshelf basal melt rates, we performed high-resolution (<1km) hindcasts of the Greenland Ice Sheet of the 1989-2012 period. These hindcasts allow us to study the processes governing ice-shelf thinning, break-up, and subsequent speed-ups and dynamic thinning. Focussing our analysis on the Jakobshavn basin we show that our simulations are able to capture the thinning of the floating tongue resulting from increased subshelf basal melt rates. Furthermore, our simulations capture both the magnitude and the timing of the dynamic thinning associated with the loss of the floating tongue, as well as the speed-up. We find little seasonal variations in surface speeds prior to 1995, and strong variations thereafter, in good agreement with observations of Echelmeyer and Harrison (1991) and Joughin et al (2012).

  10. A magnetotelluric study of continental lithosphere in the final stages of break-up. Afar, Ethiopia

    International Nuclear Information System (INIS)

    Complete text of publication follows. As part of a major programme of research into the processes and controls involved in the break-up of continents and the generation of new oceanic crust, we have collected broadband magnetotelluric data along two ∼50km long profiles in the Afar region of Ethiopia, with transient electromagnetic data for static shift control. The first is across a currently active magmatic segment that has experienced volcanic eruptions, seismic tremor and dyke injection over the last 3 years, and the other across a currently inactive segment. This presentation will concentrate on the results of the profile across the active segment. The data are broadly consistent with a two-dimensional interpretation, with geoelectrical strike along the segment's axis of rifting. Three-dimensional effects are seen primarily at sites beneath the rift axis and at longer periods. After static shift correction and rotation into TE and TM modes, we have inverted the data using the REBOCC algorithm. We find high conductivity at various depths beneath the segment axis: in a narrow zone close to the surface and in a much broader zone at depths straddling the crust-mantle interface. We interpret the deeper conductor to represent a magma chamber feeding the recent rifting episodes which has been inferred, but not previously observed directly, from a mis-match between the possible magma supply from deflation of the active volcanoes in the area and the volume of material intruded into the dykes.

  11. Coulomb breakup of neutron-rich $^{29,30}$Na isotopes near the island of inversion

    CERN Document Server

    Rahaman, A; Aumann, T; Beceiro-Novo, S; Boretzky, K; Caesar, C; Carlson, B V; Catford, W N; Chakraborty, S; Chartier, M; Cortina-Gil, D; Angelis, G De; Gonzalez-Diaz, D; Emling, H; Fernandez, P Diaz; Fraile, L M; Ershova, O; Geissel, H; Jonson, B; Johansson, H; Kalantar-Nayestanaki, N; Krücken, R; Kröll, T; Kurcewicz, J; Langer, C; Bleis, T Le; Leifels, Y; Münzenberg, G; Marganiec, J; Nilsson, T; Nociforo, C; Nowacki, F; Najafi, A; Panin, V; Paschalis, S; Plag, R; Poves, A; Ray, I; Reifarth, R; Rigollet, C; Ricciardi, V; Rossi, D; Scheit, H; Simon, H; Scheidenberger, C; Typel, S; Taylor, J; Togano, Y; Volkov, V; Weick, H; Wagner, A; Wamers, F; Weigand, M; Winfield, J S; Yakorev, D; Zoric, M

    2016-01-01

    First results are reported on the ground state configurations of the neutron-rich $^{29,30}$Na isotopes, obtained via Coulomb dissociation (CD) measurements as a method of the direct probe. The invariant mass spectra of those nuclei have been obtained through measurement of the four-momentum of all decay products after Coulomb excitation on a $^{208}Pb$ target at energies of 400-430 MeV/nucleon using FRS-ALADIN-LAND setup at GSI, Darmstadt. Integrated Coulomb-dissociation cross-sections (CD) of 89 $(7)$ mb and 167 $(13)$ mb up to excitation energy of 10 MeV for one neutron removal from $^{29}$Na and $^{30}$Na respectively, have been extracted. The major part of one neutron removal, CD cross-sections of those nuclei populate core, in its' ground state. A comparison with the direct breakup model, suggests the predominant occupation of the valence neutron in the ground state of $^{29}$Na${(3/2^+)}$ and $^{30}$Na${(2^+)}$ is the $d$ orbital with small contribution in the $s$-orbital which are coupled with ground ...

  12. On the Differences and Climate Impacts of Early and Late Stratospheric Polar Vortex Breakup

    Institute of Scientific and Technical Information of China (English)

    LI Lin; LI Chongyin; PAN Jing; TAN Yanke

    2012-01-01

    The stratospheric polar vortex breakup (SPVB) is an important phenomenon closely related to the seasonal transition of stratospheric circulation.In this paper,62-year NCEP/NCAR reanalysis data were employed to investigate the distinction between early and late SPVB.The results showed that the anomalous circulation signals extending from the stratosphere to the troposphere were reversed before and after early SPVB,while the stratospheric signals were consistent before and after the onset of late SPVB.Arctic Oscillation (AO) evolution during the life cycle of SPVB also demonstrated that the negative AO signal can propagate downward after early SPVB.Such downward AO signals could be identified in both geopotential height and temperature anomalies.After the AO signal reached the lower troposphere,it influenced the Aleutian Low and Siberian High in the troposphere,leading to a weak winter monsoon and large-scale warming at mid latitudes in Asia.Compared to early SPVB,downward propagation was not evident in late SPVB.The high-latitude tropospheric circulation in the Northern Hemisphere was affected by early SPVB,causing it to enter a summer circulation pattern earlier than in late SPVB years.

  13. Breakup structure of two-phase jets with various momentum flux from a porous injector

    Science.gov (United States)

    Lee, Inchul; Kim, Dohun; Koo, Jaye

    2014-02-01

    Spray structure and atomization characteristics were investigated through a comparison of a porous and a shear coaxial injector. The porous injector shows better atomization performance than the shear coaxial injector. To increase atomization performance and mixing efficiency of two-phase jets, a coaxial porous injector which can be applicable to liquid rocket combustors was designed and tested. The characteristics of atomization and spray from a porous and a shear coaxial injector were characterized by the momentum flux ratio. The breakup mechanism of the porous injector is governed by Taylor-Culick flow and axial shear forces. Momentum of injected gas flow through a porous material which is composed of sintered metal is radically transferred to the center of the liquid column, and then liquid column is effectively broken up. Although the shapes of spray from porous and shear coaxial jets were similar for various momentum ratio, spray structures such as spray angle and droplet sizes were different. As increasing the momentum flux ratio, SMD from the porous injector showed smaller value than the shear coaxial injector

  14. Splash wave and crown breakup after disc impact on a liquid surface

    CERN Document Server

    Peters, Ivo R; Gordillo, J M

    2012-01-01

    In this paper we analyze the impact of a circular disc on a free surface using experiments, potential flow numerical simulations and theory. We focus our attention both on the study of the generation and possible breakup of the splash wave created after the impact and on the calculation of the force on the disc. We have experimentally found that drops are only ejected from the rim located at the top part of the splash --giving rise to what is known as the crown splash-- if the impact Weber number exceeds a threshold value $\\Weber_{crit}\\simeq 140$. We explain this threshold by defining a local Bond number $Bo_{tip}$ based on the rim deceleration and its radius of curvature, with which we show using both numerical simulations and experiments that a crown splash only occurs when $Bo_{tip}\\gtrsim 1$, revealing that the rim disrupts due to a Rayleigh-Taylor instability. Neglecting the effect of air, we show that the flow in the region close to the disc edge possesses a Weber-number-dependent self-similar structur...

  15. MULTIPHASE DROPLET/SLUG BREAK-UP MECHANISM IN MICROFLUIDIC T-JUNCTIONS AT VARIOUS WEBER NUMBERS

    Directory of Open Access Journals (Sweden)

    Wan Leng (Dawn Leow

    2011-10-01

    Full Text Available Normal 0 false false false EN-MY X-NONE X-NONE The formation of immiscible liquid droplets, or slugs, in microchannels features the advantages of volume control and mixing enhancement over single-phase microflows. Although the applications of droplet-based microfluidics have been widely demonstrated, the fundamental physics governing droplet break-up remains an area of active research. This study defines an effective Weber (Weeff number that characterizes the interplay of interfacial tension, shear stress and channel pressure drop in driving slug formation in T-junction microchannel for a relative range of low, intermediate and high flow rates. The immiscible fluid system in this study consists of Tetradecane slug formation in Acetonitrile. The progressive deformation of slug interfaces during break-up events is observed. Experimental results indicate that, at a relatively low Weeff, clean slug break-up occurs at the intersection of the side and main channels. At intermediate Weeff, the connecting neck of the dispersed phase is stretched to a short and thin trail of laminar flow prior to breaking up a short distance downstream of the T-junction. At a relatively high Weeff, the connecting neck develops into a longer and thicker trail of laminar flow that breaks up further downstream of the main channel.

  16. Tectonomagmatic controls on Gondwana break-up models: Evidence from the Proto-Pacific Margin of Antarctica

    Science.gov (United States)

    Storey, Bryan C.; Alabaster, Tony

    1991-12-01

    Geochemical and isotopic data are presented that suggest the existence of a large, Middle Jurassic subduction-related magmatic province common to both the Antarctic Peninsula and southern South America. We argue that during the initial stages of Gondwana breakup, Pacific margin magmas were derived from an enriched lithospheric mantle source similar to that for the contemporaneous within-plate Ferrar-Tasman suite. Enriched lithospheric initial-rifting magmas were succeeded, in at least part of the Rocas Verdes basin, by transitional early drift magmas and then by entirely asthenospheric mid-ocean ridge basalt (MORB) magmas representing lithospheric rupture and seafloor spreading. We propose a plate interaction model for the initial stages of Gondwana breakup relating the broad zone of lithospheric mantle melting to a reduction in plate boundary forces. The change from Gondwanide compression to lithospheric extension in the Jurassic is linked to a change from shallow to steeply dipping subduction and to a slowing of subduction rates caused possibly by a decreasing age of the subducting plate. Ridge-trench interaction may have followed subduction of young, hot oceanic lithosphere, possibly causing a temporary cessation of subduction and a further reduction in plate boundary forces, thus facilitating breakup.

  17. Effects of Sediment-induced Stratification on Floc Breakup in an Idealized Tidal Estuary:A Numerical Modelling Study

    Institute of Scientific and Technical Information of China (English)

    X.H.Wang

    2004-01-01

    Floc breakup dynamics are studied by a sediment transport numerical model in an idealized tidal estuary that has a constant water depth and rapid flocculation of cohesive sediments. The focus is placed on the effects of boundary layer stratification induced by a bottom nepheloid layer on floc breakup and size distribution in the water column. In a neutrally stratified estuary, the floc size distribution follows a parabolic function with maximum values at the surface and bottom. The sediment-induced stratification in the bottom boundary layer increases the median floc sizes. Furthermore, sediment-voided convection caused by the settling lutocline generates significant turbulent kinetic energy dissipation and reduces floc size at the depth where the convective mixing happens. Below that depth, a weak local maxima in the floc size is predicted due to presence of the lutocline. The effect of sediment-stratified bottom boundary layer on the floc breakup can be consistently approximated by a linear regression between the maximal floc size and flux Richardson number.

  18. An operational calculus framework to characterize droplet size populations from turbulent breakup by a small number of parameters

    Energy Technology Data Exchange (ETDEWEB)

    Vazquez, Rafael; Ganan-Calvo, Alfonso M, E-mail: amgc@us.e [Departamento de IngenierIa Aeroespacial y Mecanica de Fluidos, Universidad de Sevilla, e-41092 Sevilla (Spain)

    2010-05-07

    A systematic operational calculus framework that characterizes droplet/bubble size distributions resulting from turbulent breakup of an immiscible fluid into a carrier one is presented. The proposed formulation is derived from dynamical arguments; a finite-difference formulation of the integro-differential continuous coagulation and fragmentation equation is shown to exhibit the same structure as a discrete sequence of Mellin convolutions between the probability distribution of the evolving dispersed phase and a generic kernel. This kernel may have its physical correspondence with the probability distribution resulting from a single breakup event, e.g. a liquid ligament breakup in a ligament-mediated spray formation. The number of convolution steps in the sequence can be reduced to a single parameter. As an illustration, this procedure is applied to the exponential and the gamma distributions, obtaining as a result the Frechet distribution earlier used by Rosin and Rammler (1934 Kolloid-Zeitschrift 67 16-26), and by Nukiyama and Tanasawa (1939 Trans. Soc. Mech. Eng. Japan 5 62-7). Thus, the framework introduced in this work provides a physical foundation for the success of the Frechet distribution in accurately fitting experimentally measured droplet size distributions in sprays and emulsions.

  19. Experimental Observations on the Deformation and Breakup of Water Droplets Near the Leading Edge of an Airfoil

    Science.gov (United States)

    Vargas, Mario; Feo, Alex

    2011-01-01

    This work presents the results of an experimental study on droplet deformation and breakup near the leading edge of an airfoil. The experiment was conducted in the rotating rig test cell at the Instituto Nacional de Tecnica Aeroespacial (INTA) in Madrid, Spain. An airfoil model placed at the end of the rotating arm was moved at speeds of 50 to 90 m/sec. A monosize droplet generator was employed to produce droplets that were allowed to fall from above, perpendicular to the path of the airfoil at a given location. High speed imaging was employed to observe the interaction between the droplets and the airfoil. The high speed imaging allowed observation of droplet deformation and breakup as the droplet approached the airfoil near the stagnation line. A tracking software program was used to measure from the high speed movies the horizontal and vertical displacement of the droplet against time. The velocity, acceleration, Weber number, Bond number, Reynolds number, and the drag coefficients were calculated along the path of a given droplet from beginning of deformation to breakup and/or hitting the airfoil. Results are presented for droplets with a diameter of 490 micrometers at airfoil speeds of 50, 60, 70, 80 and 90 m/sec

  20. Determination of S17 from 8B breakup by means of the method of continuum-discretized coupled-channels

    CERN Document Server

    Ogata, K; Iseri, Y; Kamimura, M; Yahiro, M

    2006-01-01

    The astrophysical factor for 7Be(p,\\gamma)8B at zero energy, S17(0), is determined from 208Pb(8B, p+7Be)208Pb at 52 MeV/nucleon. We use the method of continuum-discretized coupled-channels (CDCC) to accurately calculate the 8B breakup cross section, taking account of nuclear breakup, Coulomb dipole and quadrupole transitions and higher-order processes. The asymptotic normalization coefficient (ANC) method is used to extract S17(0) from the calculated breakup-cross-section. The main result of the present paper is S17(0)=21.4 +2.0/-1.9 eV b. This result has +4.5%/-2.6% theoretical error, which comes from ambiguity of the p-7Be scattering length, and 8.4% systematic experimental error. CDCC calculation with one-step Coulomb dipole transitions results in a smaller value of S17(0), 20.2 eV b, which is almost consistent with the extracted value with the first-order perturbation theory: 18.9 eV b. Inclusion of Coulomb quadrupole transitions in one-step CDCC calculation is found to give further reduction of S17(0), i...

  1. Incomplete fusion reactions in 16O+165Ho

    Indian Academy of Sciences (India)

    Anil Sharma; B Bindu Kumar; S Mukherjee; S Chakrabarty; B S Tomar; A Goswami; G K Gubbi; S B Manohar; A K Sinha; S K Datta

    2000-03-01

    Excitation functions for evaporation residues of the system 16O+165Ho have been measured up to 100 MeV. Recoil range distribution of long lived reaction products were measured at 16O beam energy of 100 MeV. Detailed Monte Carlo simulation of recoil range distributions of products were performed with the help of PACE2 code, in order to extract the contributions of incomplete fusion in the individual channels. The results clearly show the incomplete fusion contributions in the tantalum and thulium products. This is confirmed by the predictions of breakup fusion model of the incomplete fusion.

  2. Dynamics of GeV light-ion-induced reactions

    International Nuclear Information System (INIS)

    Recent results from studies of the 1.8 - 4.8 GeV 3He + natAg, 197Au reactions at LNS with the ISiS detector array have shown evidence for a saturation in deposition energy and multifragmentation from a low-density source. The collision dynamics have been examined in the context of intranuclear cascade and BUU models, while breakup phenomena have been compared with EES and SMM models. Fragment-fragment correlations and isotope ratios are also investigated. (K.A.)

  3. Establishing a theory for deuteron induced surrogate reactions

    CERN Document Server

    Aguilar, Gregory Potel; Thompson, Ian J

    2015-01-01

    The goal of this work is to establish on firm grounds a theory for deuteron induced neutron capture reactions. This includes formulating elastic and inelastic breakup in a consistent manner. We describe this process both in post and prior form distorted wave Born approximation, and we apply our method to the 53Nb(d,p)X at Ed =15 MeV and 25 MeV, obtaining a good description of the data. We look at the various partial wave contributions, as well as elastic versus inelastic contributions. We also connect our formulation with transfer to neutron bound states.

  4. Dynamics of GeV light-ion-induced reactions

    Energy Technology Data Exchange (ETDEWEB)

    Kwiatkowski, K.; Bracken, D.S.; Foxford, E.R.; Ginger, D.S.; Hsi, W.C.; Morley, K.B.; Viola, V.E.; Wang, G. [Indiana Univ., Bloomington, IN (United States). Dept. of Chemistry; Korteling, R.G. [Simon Fraser Univ., Burnaby, BC (Canada). Dept. of Chemistry; Legrain, R. [CEA Centre d`Etudes de Saclay, 91 - Gif-sur-Yvette (France). Dept. d`Astrophysique, de la Physique des Particules, de la Physique Nucleaire et de l`Instrumentation Associee] [and others

    1996-09-01

    Recent results from studies of the 1.8 - 4.8 GeV {sup 3}He + {sup nat}Ag, {sup 197}Au reactions at LNS with the ISiS detector array have shown evidence for a saturation in deposition energy and multifragmentation from a low-density source. The collision dynamics have been examined in the context of intranuclear cascade and BUU models, while breakup phenomena have been compared with EES and SMM models. Fragment-fragment correlations and isotope ratios are also investigated. (K.A.). 19 refs.

  5. Calculation of Double-Differential Cross Sections of n+7Li Reactions Below 20 MeV

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jing-Shang; HAN Ying-Lu

    2002-01-01

    A new reaction model for light nuclei is proposed to analyze the measured data,especially for analysis of the double-differential cross sections of the outgoing particles.Many channels arc opened in the n + 7Li reaction below En< 20 MeV.The reaction mechanism is very complex,beside the sequential emissions there are also three-body breakup processes.Because of a strong recoil effect of light nucleus reactions,the energy balance is strictly taken into account.The comparisons of the calculated results with the double-differential measurements indicate that the model calculations are successful for the total outgoing neutrons.

  6. Comparative analysis of post-breakup basin evolution along the South-American and South-African margins, southern Atlantic

    Science.gov (United States)

    Strozyk, F.; Back, S.; Kukla, P. A.

    2012-04-01

    Recently, considerable attempts have been made to compare the sedimentary basin evolution and the associated tectonic framework on both sides of the South-Atlantic. However, yet there are still unresolved questions concerning the tectono-sedimentary styles of margin basin evolution that markedly differ from north to south. Amongst the most striking observations is that multiple phases of uplift and subsidence are recorded after the break-up of the southern South Atlantic margin segment on both sides of the Florianopolis-Walvis Ridge volcanic complex, features that are regarded as atypical when compared to published examples of other post-breakup margin successions. Adding to the heterogeneity of the system, the northernmost segment of the South Atlantic rift and salt basins is also characterized by a pronounced asymmetry, with the Brazilian margin now comprising narrower and deeper rift basins with less salt than the Congo-Gabon conjugate margin. This project deals with a large-scale comparison of this very different post-breakup tectono-stratigraphic development of the southern and northern South American and African continental margins that both record thick post-rift sedimentary successions. To gain detail of the basin margin evolution, we focus on a regional comparison between the post-breakup records archived in the large offshore southern Brazil basins (Pelotas, Santos, Campos) and the post-breakup continental margin successions of offshore Namibia (e.g. Orange Basin) and southern Angola (e.g. Kwanza Basin). A tectonic-stratigraphic comparison of representative geological transects provides a comprehensive basin-to-basin documentation of key factors influencing margin development which include the subsidence development through time, the sediment (in-)flux and storage patterns and the respective type of basin fill (e.g. salt vs. non-salt systems; carbonate-rich vs. clastics-dominated systems). Data from the salt-prone areas offshore South America and southern

  7. Spectator invariance test in the study of the Trojan Horse Method 6,7Li fusion reactions via the Trojan Horse Method

    Directory of Open Access Journals (Sweden)

    Li C.

    2011-10-01

    Full Text Available Fusion reactions play a crucial role for several astrophysical scenarios. At the low energies typical of such environments direct measurements of reaction cross sections are very difficult, and even sometimes impossible. In such cases the use of indirect methods can give a substantial help. The Trojan Horse Method (THM is based on the quasi-free break-up of a nucleus, which can be described in terms of a cluster structure. In such applications the independence of THM results with different break-up schemes, was tested using the quasi free3 He(6Li,ααH and 3He(7Li,αα2H reactions. Results were then compared with the direct behaviours obtained from available data as well as with the cross sections extracted from previous indirect investigations of the same binary reactions using a different nuclide as a Trojan Horse nucleus.

  8. Mantle Plume Temperature Variations Immediately Following Continental Breakup of the Northern North Atlantic

    Science.gov (United States)

    Parkin, C. J.; White, R. S.; Kusznir, N. J.

    2005-05-01

    The amount of melt generated by mantle decompression beneath an oceanic spreading centre and hence the oceanic crustal thickness is controlled in part by the temperature of the mantle. By measuring the thickness of the oceanic crust formed immediately after breakup of the northern North Atlantic during the early Tertiary, we are able to deduce the maximum elevated mantle temperatures caused by the presence of the Iceland mantle plume. Crustal thickness variations are caused by temporal variations in the mantle plume temperature: at the present Reykjanes Ridge spreading centre the plume temperature pulses on a 3-5 Myr timescale with temperature variations of c.30 K. We show results from two long-offset profiles acquired over oceanic crust; firstly a 170km line perpendicular to the Faroes rifted continetal margin where oceanic spreading developed close to the Iceland mantle plume; and secondly, a 200km line perpendicular to the Hatton rifted continental margin where oceanic spreading developed 800km south of the plume. Each survey recorded long-offset refractions and reflections on OBS (Ocean Bottom Seismometers); 25 instruments, with a spacing of 2-3 km, were used for the Faroes line; and 45 instruments, with a spacing of 4-10 km were used for the Hatton-Rockall line. Accurate information for sediment velocity and thickness was acquired for the Faroes profile using a 12 km long streamer; whilst adequate sediment information was determined for the Hatton-Rockall profile using a 2.4 km streamer. By incorporating sediment structure into a joint reflection and refraction tomographic inversion of the wide-angle OBS data, we have been able to map crustal thickness across the oceanic crust in both regions. Crustal sections across the Faroes and Hatton lines cover the first 14 Myr and 17 Myr respectively, corresponding to the time interval from continental breakup through to mature seafloor spreading. With no apparent decrease in spreading rate observed thinning of the

  9. Extraction of a single soliton from a bunch of solitons generated by pulse breakup

    Science.gov (United States)

    Bello-Jimenez, Miguel A.; Kuzin, Evgeny A.; Pottiez, Olivier; Ibarra-Escamilla, Baldemar; Flores-Rosas, Ariel; Duran-Sanchez, Manuel

    2010-02-01

    Pulses propagating in the fiber with anomalous dispersion are broken up to the bunch of soliton. The extraction of an individual soliton from the bunch can be used for soliton generation and also for investigation of the process of the soliton formation. In this work we experimentally demonstrate that the NOLM allows extraction of an individual soliton. Earlier we have shown numerically that the NOLM has high transmission for the solitons with a range of durations while solitons with shorter and longer durations are rejected. The range of the durations with high transmission depends on the NOLM length and also can be moved by amplification of solitons before entering to the NOLM. In the experiment we launched 25-ps pulses with about 10 W of power to the 500-m single mode fiber with dispersion equal to 20 ps/nm-km. As a result of the pulse breakup, a bunch of solitons is formed at the fiber output. The resulting solitons are launched to the EDFA and then to the NOLM made from the 40-m of the same fiber. The NOLM parameters are adjusted to transmit the highest soliton in the bunch (about 50 W of power and 1 ps of duration according to theoretical estimations). In the experiment we detected at the NOLM output a single pulse with duration of 1.46 ps and autocorrelation function similar to that of the soliton. When a 1-km fiber was attached to the NOLM at the fiber output we detected a soliton with duration of 0.9 ps.

  10. Upper mantle temperature and the onset of extension and break-up in Afar, Africa

    Science.gov (United States)

    Armitage, John J.; Ferguson, David J.; Goes, Saskia; Hammond, James O. S.; Calais, Eric; Rychert, Catherine A.; Harmon, Nicholas

    2015-05-01

    It is debated to what extent mantle plumes play a role in continental rifting and eventual break-up. Afar lies at the northern end of the largest and most active present-day continental rift, where the East African Rift forms a triple junction with the Red Sea and Gulf of Aden rifts. It has a history of plume activity yet recent studies have reached conflicting conclusions on whether a plume still contributes to current Afar tectonics. A geochemical study concluded that Afar is a mature hot rift with 80 km thick lithosphere, while seismic data have been interpreted to reflect the structure of a young, oceanic rift basin above mantle of normal temperature. We develop a self-consistent forward model of mantle flow that incorporates melt generation and retention to test whether predictions of melt chemistry, melt volume and lithosphere-asthenosphere seismic structure can be reconciled with observations. The rare-earth element composition of mafic samples at the Erta Ale, Dabbahu and Asal magmatic segments can be used as both a thermometer and chronometer of the rifting process. Low seismic velocities require a lithosphere thinned to 50 km or less. A strong positive impedance contrast at 50 to 70 km below the rift seems linked to the melt zone, but is not reproduced by isotropic seismic velocity alone. Combined, the simplest interpretation is that mantle temperature below Afar is still elevated at 1450 °C, rifting started around 22-23 Ma, and the lithosphere has thinned from 100 to 50 km to allow significant decompressional melting.

  11. New Laboratory-Based Satellite Impact Experiments for Breakup Fragment Characterization

    Science.gov (United States)

    Liou, J.-C.; Fitz-Coy, N.; Dikova, R.; Wilson, M.; Huynh, T.; Sorge, M.; Sheaffer, P.; Opiela, J.; Cowardin, H.; Krisko, P.; Rushing, R.; Nolen, M.; Roebuck, B.

    2014-01-01

    A consortium consisting of the NASA Orbital Debris Program Office, U.S. Air Force's Space and Missile Systems Center, the Aerospace Corporation, and University of Florida is planning a series of hypervelocity impact experiments on mockup targets at the U.S. Air Force's Arnold Engineering Development Complex (AEDC) in early 2014. The target for the first experiment resembles a rocket upper stage whereas the target for the second experiment represents a typical 60-cm/50-kg class payload that incorporates modern spacecraft materials and components as well as exterior wrap of multi-layer insulation and three solar panels. The projectile is designed with the maximum mass that AEDC's Range G two-stage light gas gun can accelerate to an impact speed of 7 km/sec. The impact energy is expected to be close to 15 MJ to ensure catastrophic destruction of the target after the impact. Low density foam panels are installed inside the target chamber to slow down and soft-catch the fragments for post-impact processing. Diagnostic instruments, such as x-ray and high speed optical cameras, will also be used to record the breakup process. The main goal of this "DebriSat" project is to characterize the physical properties, including size, mass, shape, and density distributions, of orbital debris that would be generated by a hypervelocity collision involving an upper stage or a modern satellite in the low Earth orbit environment. In addition, representative fragments will be selected for laboratory optical and radar measurements to allow for better interpretation of data obtained by telescope and radar observations. This paper will provide a preliminary report of the impact results and the plans to process, measure, and analyze the fragments.

  12. New Laboratory-Based Satellite Impact Experiments for Breakup Fragment Characterization

    Science.gov (United States)

    Liou, J.-C.

    A consortium consisting of the NASA Orbital Debris Program Office, U.S. Air Force’s Space and Missile Systems Center, The Aerospace Corporation, and University of Florida is planning a series of hypervelocity impact experiments on mockup targets at the U.S. Air Force’s Arnold Engineering Development Complex (AEDC) in early 2014. The target for the first experiment resembles a rocket upper stage whereas the target for the second experiment represents a typical 60-cm/50-kg class payload that incorporates modern spacecraft materials and components as well as exterior wrap of multi-layer insulation and three solar panels. The projectile is designed with the maximum mass that AEDC’s Range G two-stage light gas gun can accelerate to an impact speed of 7 km/sec. The impact energy is expected to be close to 15 MJ to ensure catastrophic destruction of the target after the impact. Low density foam panels are installed inside the target chamber to slow down and soft-catch the fragments for post-impact processing. Diagnostic instruments, such as x-ray and high speed optical cameras, will also be used to record the breakup process. The main goal of this “DebriSat” project is to characterize the physical properties, including size, mass, shape, and density distributions, of orbital debris that would be generated by a hypervelocity collision involving an upper stage or a modern satellite in the low Earth orbit environment. In addition, representative fragments will be selected for laboratory optical and radar measurements to allow for better interpretation of data obtained by telescope and radar observations. This paper will provide a preliminary report of the impact results and the plans to process, measure, and analyze the fragments.

  13. Experiment E89-044 on the Quasielastic 3He(e,e'p) Reaction at Jefferson Laboratory

    Energy Technology Data Exchange (ETDEWEB)

    Penel-Nottaris, Emilie [Univ. Joseph Fourier Grenoble (France)

    2004-07-07

    The Jefferson Lab Hall A E89-044 experiment has measured the 3He(e,e'p) reaction cross-sections. The extraction of the longitudinal and transverse response functions for the two-body break-up 3He(e,e'p)d reaction in parallel kinematics allows the study of the bound proton electromagnetic properties inside the 3He nucleus and the involved nuclear mechanisms beyond plane wave approximations.

  14. Role of the total isospin 3/2 component in three-nucleon reactions

    CERN Document Server

    Witala, H; Skibinski, R; Topolnicki, K; Epelbaum, E; Hebeler, K; Kamada, H; Krebs, H; Meissner, U -G; Nogga, A

    2016-01-01

    We discuss the role of the three-nucleon isospin T=3/2 amplitude in elastic neutron-deuteron scattering and in the deuteron breakup reaction. The contribution of this amplitude originates from charge-independence breaking of the nucleon-nucleon potential and is driven by the difference between neutron-neutron (proton-proton) and neutron-proton forces. We study the magnitude of that contribution to the elastic scattering and breakup observables, taking the locally regularized chiral N4LO nucleon-nucleon potential supplemented by the chiral N2LO three-nucleon force. For comparison we employ also the Av18 nucleon-nucleon potential combined with the Urbana IX three-nucleon force. We find that the isospin T=3/2 component is important for the breakup reaction and the proper treatment of charge-independence breaking in this case requires the inclusion of the 1S0 state with isospin T=3/2. For neutron-deuteron elastic scattering the T=3/2 contributions are insignificant and charge-independence breaking can be accounte...

  15. Low-energy neutron-deuteron reactions with N{sup 3}LO chiral forces

    Energy Technology Data Exchange (ETDEWEB)

    Golak, J.; Skibinski, R.; Topolnicki, K.; Witala, H. [Jagiellonian University, M. Smoluchowski Institute of Physics, Krakow (Poland); Epelbaum, E.; Krebs, H. [Ruhr-Universitaet Bochum, Institut fuer Theoretische Physik II, Bochum (Germany); Kamada, H. [Kyushu Institute of Technology, Department of Physics, Faculty of Engineering, Kitakyushu (Japan); Meissner, Ulf G. [Universitaet Bonn, Helmholtz-Institut fuer Strahlen- und Kernphysik and Bethe Center for Theoretical Physics, Bonn (Germany); JARA - High Performance Computing Forschungszentrum Juelich, Institute for Advanced Simulation, Institut fuer Kernphysik, Juelich Center for Hadron Physics, Juelich (Germany); Bernard, V. [CNRS/Univ. Paris-Sud, Institut de Physique Nucleaire, Orsay (France); Maris, P.; Vary, J. [Iowa State University, Department of Physics and Astronomy, Ames, Iowa (United States); Binder, S.; Calci, A.; Langhammer, J.; Roth, R. [Technische Universitaet Darmstadt, Institut fuer Kernphysik, Darmstadt (Germany); Hebeler, K. [Technische Universitaet Darmstadt, Institut fuer Kernphysik, Darmstadt (Germany); GSI Helmholtzzentrum fuer Schwerionenforschung GmbH, Extreme Matter Institute EMMI, Darmstadt (Germany); Nogga, A. [Juelich Center for Hadron Physics, Forschungszentrum Juelich, Institut fuer Kernphysik, Institute for Advanced Simulation, Juelich (Germany); Liebig, S.; Minossi, D. [Juelich Center for Hadron Physics, Forschungszentrum Juelich, Institut fuer Kernphysik, Juelich (Germany)

    2014-11-15

    We solve three-nucleon Faddeev equations with nucleon-nucleon and three-nucleon forces derived consistently in the framework of chiral perturbation theory at next-to-next-to-next-to-leading order in the chiral expansion. In this first investigation we include only matrix elements of the three-nucleon force for partial waves with the total two-nucleon (three-nucleon) angular momenta up to 3 (5/2). Low-energy neutron-deuteron elastic scattering and deuteron breakup reaction are studied. Emphasis is put on A{sub y} puzzle in elastic scattering and cross sections in symmetric-space-star and neutron-neutron quasi-free-scattering breakup configurations, for which large discrepancies between data and theory have been reported. (orig.)

  16. Low-energy neutron-deuteron reactions with N3LO chiral forces

    CERN Document Server

    Golak, J; Topolnicki, K; Witala, H; Epelbaum, E; Krebs, H; Kamada, H; Meissner, Ulf-G; Bernard, V; Maris, P; Vary, J; Binder, S; Calci, A; Hebeler, K; Langhammer, J; Roth, R; Nogga, A; Liebig, S; Minossi, D

    2014-01-01

    We solve three-nucleon Faddeev equations with nucleon-nucleon and three-nucleon forces derived consistently in the framework of chiral perturbation theory at next-to-next-to-next-to-leading order in the chiral expansion. In this first investigation we include only matrix elements of the three-nucleon force for partial waves with the total two-nucleon (three-nucleon) angular momenta up to 3 (5/2). Low-energy neutron-deuteron elastic scattering and deuteron breakup reaction are studied. Emphasis is put on Ay puzzle in elastic scattering and cross sections in symmetric-space-star and neutron-neutron quasi-free-scattering breakup configurations, for which large discrepancies between data and theory have been reported.

  17. Analytical tool development for coarse break-up of a molten jet in a deep water pool

    Energy Technology Data Exchange (ETDEWEB)

    Moriyama, Kiyofumi [Thermohydraulic Safety Research Group, Japan Atomic Energy Agency (JAEA), 2-4 Shirakata-shirane, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan)]. E-mail: moriyama.kiyofumi@jaea.go.jp; Nakamura, Hideo [Thermohydraulic Safety Research Group, Japan Atomic Energy Agency (JAEA), 2-4 Shirakata-shirane, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan); Maruyama, Yu [Thermohydraulic Safety Research Group, Japan Atomic Energy Agency (JAEA), 2-4 Shirakata-shirane, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan)

    2006-10-15

    A computer code JASMINE-pre was developed for the prediction of premixing conditions of fuel-coolant interactions and debris bed formation behavior relevant to severe accidents of light water reactors. In JASMINE-pre code, a melt model which consists of three components of sub-models for melt jet, melt particles and melt pool, is coupled with a two-phase flow model derived from ACE-3D code developed at JAERI. The melt jet and melt pool models are one-dimensional representations of a molten core stream falling into a water pool and a continuous melt body agglomerated on the bottom, respectively. The melt particles generated by the melt jet break-up are modeled based on a Lagrangian grouped particle concept. Additionally, a simplified model pmjet was developed which considers only steady state break-up of the melt jet, cooling and settlement of particles in a stationary water pool. The FARO corium quenching experiments with a saturation temperature water pool and a subcooled water pool were simulated with JASMINE-pre and pmjet. JASMINE-pre reproduced the pressurization and fragmentation behavior observed in the experiments with a reasonable accuracy. Also, the influences of model parameters on the pressurization and fragmentation were examined. The calculation results showed a quasi-steady state phase of melt jet break-up during which the amount of molten mass contained in the premixture was kept almost constant, and the steady state molten premixed masses evaluated by JASMINE-pre and pmjet agreed well.

  18. Study of the p+{sup 12}C reaction at energies up to 30 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Harada, Masahide; Yamamoto, A.; Yoshioka, S. [Kyushu Univ., Fukuoka (Japan)] [and others

    1998-03-01

    Double differential cross sections of charged-particles emitted in the p+{sup 12}C reaction were measured in the energy region from 14 to 26 MeV. The observed continuous components of emitted protons and {alpha}-particles were analyzed by assuming sequential decay of intermediate reaction products and/or simultaneous breakup process. It was found that the three body simultaneous decay, p+{alpha}+{sup 8}Be, and the sequential decay via p+{sup 12}C{sup *}{sub 3-} and {alpha}+{sup 9}B{sub g.s.} are most important in the proton-induced breakup of {sup 12}C for energies up to 30 MeV. (author)

  19. Updated evidences of the Trojan Horse particle invariance for $^2$H(d,p)$^3$H reaction

    CERN Document Server

    Pizzone, R G; Bertulani, C A; Mukhamedzhanov, A M; Blokhintsev, L; La Cognata, M; Lamia, L; Rinollo, A; Spartá, R; Tumino, A

    2012-01-01

    The Trojan Horse nucleus invariance for the binary d(d,p)t reaction was tested using the quasi free $^2$H($^6$Li, pt)$^4$He and $^2$H($^3$He,pt)H reactions after $^6$Li and $^3$He break-up, respectively. The astrophysical S(E)-factor for the d(d,p)t binary process was then extracted in the framework of the Plane Wave Approximation applied to the two different break-up schemes. The obtained results are compared with direct data as well as with previous indirect investigations. The very good agreement confirms the applicability of the Plane Wave Approximation and suggests the independence of binary indirect cross section on the chosen Trojan Horse nucleus also for the present case.

  20. Updated evidence of the Trojan horse particle invariance for the 2H(d,p)3H reaction

    Science.gov (United States)

    Pizzone, R. G.; Spitaleri, C.; Bertulani, C. A.; Mukhamedzhanov, A. M.; Blokhintsev, L.; La Cognata, M.; Lamia, L.; Rinollo, A.; Spartá, R.; Tumino, A.

    2013-02-01

    The Trojan horse nucleus invariance for the binary d(d,p)t reaction was tested by means of an experiment using the quasifree 2H(6Li,pt)4He and 2H(3He,pt)H reactions after 6Li and 3He breakup, respectively. The astrophysical S(E) factor for the d(d,p)t binary process was extracted from the present data in the framework of the plane wave approximation applied to the two different breakup schemes. The obtained results are compared with direct data as well as with previous indirect investigations. The very good agreement confirms the applicability of the plane wave approximation and suggests the independence of the binary indirect cross section on the chosen Trojan horse nucleus also for the present case.

  1. Three-Body Model Analysis of Subbarrier alpha Transfer Reaction

    CERN Document Server

    Fukui, Tokuro; Yahiro, Masanobu

    2011-01-01

    Subbarrier alpha transfer reaction 13C(6Li,d)17O(6.356 MeV, 1/2+) at 3.6 MeV is analyzed with a alpha + d + 13C three-body model, and the asymptotic normalization coefficient (ANC) for alpha + 13C --> 17O(6.356 MeV, 1/2+), which essentially determines the reaction rate of 13C(alpha,n)16O, is extracted. Breakup effects of 6Li in the initial channel and those of 17O in the final channel are investigated with the continuum-discretized coupled-channels method (CDCC). The former is found to have a large back-coupling to the elastic channel, while the latter turns out significantly small. The transfer cross section calculated with Born approximation to the transition operator, including breakup states of 6Li, gives (C_{alpha 13C}{17O*})^2 =1.03 \\pm 0.29 fm^{-1}. This result is consistent with the value obtained by the previous DWBA calculation.

  2. Application of the Constrained Admissible Region Multiple Hypothesis Filter to Initial Orbit Determination of a Break-up

    Science.gov (United States)

    Kelecy, Tom; Shoemaker, Michael; Jah, Moriba

    2013-08-01

    A break-up in Low Earth Orbit (LEO) is simulated for 10 objects having area-to-mass ratios (AMR's) ranging from 0.1-10.0 m2/kg. The Constrained Admissible Region Multiple Hypothesis Filter (CAR-MHF) is applied to determining and characterizing the orbit and atmospheric drag parameters (CdA/m) simultaneously for each of the 10 objects with no a priori orbit or drag information. The results indicate that CAR-MHF shows promise for accurate, unambiguous and autonomous determination of the orbit and drag states.

  3. Target-charge dependence of the breakup coupling effects in the elastic scattering of {sup 8}B

    Energy Technology Data Exchange (ETDEWEB)

    Kucuk, Y. [University of Padova, Department of Physics and Astronomy ' ' G. Galilei' ' (Italy); Akdeniz University, Department of Physics, Antalya (Turkey); INFN, Padova (Italy); Aciksoz, E. [Technische Universitaet Darmstadt, Institut fuer Kernphysik, Darmstadt (Germany); Akdeniz University, Department of Physics, Antalya (Turkey)

    2016-04-15

    We perform continuum discretized coupled-channels calculations for the elastic scattering of {sup 8}B on different targets to trace where the Coulomb-nuclear breakup coupling effects start to be dominant in the interaction of the proton halo nuclei. We observe a qualitative difference in angular distributions when the charge of the target increases as seen in the case of neutron halos, but the Coulomb-nuclear interference peak begins to disappear clearly at a relatively smaller value of Z{sub T} for the proton halos. (orig.)

  4. Direct measurement of wave-front distortion induced during second-harmonic generation: application to breakup-integral compensation.

    Science.gov (United States)

    Caumes, Jean Pascal; Videau, Laurent; Rouyer, Claude; Freysz, Eric

    2004-04-15

    The wave-front distortion of femtosecond laser pulses recorded with a Shack-Hartmann analyzer makes it possible to retrieve the nonlinear index of refraction of different glasses and the nonlinear phase shift induced during second-harmonic generation in beta-barium borate (BBO) crystal versus the phase mismatch. It is shown that the nonlinear phase shift induced in a 2-mm-thick BBO crystal allows compensation for up to a 2pi breakup-integral induced in a 4-cm fused-silica glass. The stability of the compensation is reported to be from 10 to 100 GW cm(-2).

  5. Direct measurement of wave-front distortion induced during second-harmonic generation: application to breakup-integral compensation.

    Science.gov (United States)

    Caumes, Jean Pascal; Videau, Laurent; Rouyer, Claude; Freysz, Eric

    2004-04-15

    The wave-front distortion of femtosecond laser pulses recorded with a Shack-Hartmann analyzer makes it possible to retrieve the nonlinear index of refraction of different glasses and the nonlinear phase shift induced during second-harmonic generation in beta-barium borate (BBO) crystal versus the phase mismatch. It is shown that the nonlinear phase shift induced in a 2-mm-thick BBO crystal allows compensation for up to a 2pi breakup-integral induced in a 4-cm fused-silica glass. The stability of the compensation is reported to be from 10 to 100 GW cm(-2). PMID:15119415

  6. Lithosphere erosion and breakup due to the interaction between extension and plume upwelling

    Science.gov (United States)

    Lavecchia, Alessio; Thieulot, Cedric; Beekman, Fred; Cloetingh, Sierd; Clark, Stuart

    2016-04-01

    of melts contributes in weakening the crust and the uppermost lithospheric mantle, thus favoring the plate rupture and blocks drifting. Our results seem to exclude the possibility that forces related to plumes uprising are capable of breaking off the plates and cause blocks drifting. On the other hand, we support the possibility that plume uprising may strongly favor plate breakup, when combined with external far field forces.

  7. Global tectonics since the breakup of Pangea 180 million years ago: evolution maps and lithospheric budget

    Science.gov (United States)

    Weijermars, Ruud

    Pangea, the Earth's youngest single supercontinent, broke up 180 million years ago. Tectonic plates were subsequently formed by dispersal of the continental fragments and accretion of new oceanic lithosphere. The configurations of all the major lithospheric plates at 0, 20, 65, 95, 140, 180 Ma BP are reconstructed on six globes of the Earth, each with a radius of 10 cm. It appears that plate boundaries maintain a remarkably close fit on model globes of constant radii if the reconstructions include the recovery of subducted spreading patterns. This is illustrated with maps in equatorial orthographic, oblique orthographic and transverse Hammer-Aitoff projections. The snug fit of the tectonic plates at every tested time since the breakup of Pangea 180 Ma BP is consistent with the theory of plate tectonics on a non-expanding Earth and contradicts rapidly expanding Earth models. The areas of oceanic lithosphere produced and consumed during the past 180 Ma BP are estimated from surface measurements of the globes reconstructed on the basis of particular assumptions. These measurements suggest a consistent increase in the production rate of oceanic lithosphere during the past 140 Ma. It was decided to revise the assumptions and see if alternative reconstructions of the ancient spreading patterns on the floors of the Tethys and Eo-Pacific oceans could avoid implying an increase of lithospheric production rates with time. This appeared to be possible. The revised maps suggest that ophiolites older than 180 Ma BP may have been obducted in Cenozoic collision zones of the Himalayas, Andes, Rockies, and the western part of the Banda Arc (Timor, New Guinea). Estimates of the ocean floor production and consumption budget appear to be quite similar for both map series, and only the possible ranges are summarized here, time averaged for the past 180 Ma. World-wide production and consumption of oceanic lithosphere appears to have varied between 2.6 and 3.5 km 2 a -1 at most. The mean

  8. Recent Results on Fusion and Direct Reactions with Weakly Bound Stable Nuclei

    Directory of Open Access Journals (Sweden)

    Shrivastava A.

    2011-10-01

    Full Text Available Recent measurements of fusion and direct reactions in case of weakly bound stable nuclei at extreme sub-barrier energies using a sensitive off beam technique are presented. Deviation in slope of the fusion excitation function, as observed in case of medium heavy systems, is absent in the present asymmetric systems at these low energies. These results along with the study of capture reaction of the breakup fragments using particle- gamma coincidences is presented, thereby giving the current status of the field.

  9. Piezonuclear Reactions

    CERN Document Server

    Cardone, Fabio; Petrucci, Andrea

    2010-01-01

    In this paper, we deal with the subject of piezonuclear reactions, namely nuclear reactions (of new type) triggered by pressure waves. We discuss the experimental evidences obtained in the last two decades, which can be summarized essentially as follows: experiments in cavitation of liquids, where transmutation of elements, creation of elements and emission of neutrons have been observed; emission of neutrons in brittle failure of solids subjected to mechanical pressure; alteration of the lifetime of un unstable element (thorium) subjected to cavitation. A theoretical model to explain these facts is proposed. Future perspectives of these experimental and theoretical investigations are also underlined.

  10. Heavy ion reactions around the Coulomb barrier

    Institute of Scientific and Technical Information of China (English)

    2011-01-01

    The angular distributions of fission fragments for the 32S+184W reaction near Coulomb barrier energies are measured. The ex perimental fission excitation function is obtained. The measured fission cross sections are decomposed into fusion-fission, quasi-fission and fast fission contributions by the dinuclear system (DNS) model. The hindrance to completing fusion both at small and large collision energies is explained. The fusion excitation functions of 32S+90,96Zr in an energy range from above to below the Coulomb barrier are measured and analyzed within a semi-classical model. The obvious effect of positive Q-value multi-neutron transfers on the sub-barrier fusion enhancement is observed in the 32S+96Zr system. In addition, the excitation functions of quasi-elastic scattering at a backward angle have been measured with high precision for the systems of 16O+208Pb, 196Pt, 184W, and 154,152Sm at energies well below the Coulomb barrier. Considering the deformed coupling effects, the extracted diffuseness parameters are close to the values extracted from the systematic analysis of elastic and inelastic scattering data. The elastic scattering angular distribution of 17F+12C at 60 MeV is measured and calculated by using the continuum-discretized coupled-channels (CDCC) approach. It is found that the diffuseness parameter of the real part of core-target potential has to be increased by 20% to reproduce the experimental result, which corresponds to an increment of potential depth at the surface re gion. The breakup cross section and the coupling between breakup and elastic scattering are small.

  11. Marital satisfaction and break-ups differ across on-line and off-line meeting venues.

    Science.gov (United States)

    Cacioppo, John T; Cacioppo, Stephanie; Gonzaga, Gian C; Ogburn, Elizabeth L; VanderWeele, Tyler J

    2013-06-18

    Marital discord is costly to children, families, and communities. The advent of the Internet, social networking, and on-line dating has affected how people meet future spouses, but little is known about the prevalence or outcomes of these marriages or the demographics of those involved. We addressed these questions in a nationally representative sample of 19,131 respondents who married between 2005 and 2012. Results indicate that more than one-third of marriages in America now begin on-line. In addition, marriages that began on-line, when compared with those that began through traditional off-line venues, were slightly less likely to result in a marital break-up (separation or divorce) and were associated with slightly higher marital satisfaction among those respondents who remained married. Demographic differences were identified between respondents who met their spouse through on-line vs. traditional off-line venues, but the findings for marital break-up and marital satisfaction remained significant after statistically controlling for these differences. These data suggest that the Internet may be altering the dynamics and outcomes of marriage itself. PMID:23733955

  12. Effects of viscoelasticity on droplet dynamics and break-up in microfluidic T-Junctions: a lattice Boltzmann study

    CERN Document Server

    Gupta, Anupam

    2015-01-01

    The effects of viscoelasticity on the dynamics and break-up of fluid threads in microfluidic T-junctions are investigated using numerical simulations of dilute polymer solutions at changing the Capillary number ($\\mbox {Ca}$), i.e. at changing the balance between the viscous forces and the surface tension at the interface, up to $\\mbox{Ca} \\approx 3 \\times 10^{-2}$. A Navier-Stokes (NS) description of the solvent based on the lattice Boltzmann models (LBM) is here coupled to constitutive equations for finite extensible non-linear elastic dumbbells with the closure proposed by Peterlin (FENE-P model). We present the results of three-dimensional simulations in a range of $\\mbox{Ca}$ which is broad enough to characterize all the three characteristic mechanisms of breakup in the confined T-junction, i.e. ${\\it squeezing}$, ${\\it dripping}$ and ${\\it jetting}$ regimes. The various model parameters of the FENE-P constitutive equations, including the polymer relaxation time $\\tau_P$ and the finite extensibility para...

  13. Connections Between the Spring Breakup of the Southern Hemisphere Polar Vortex, Stationary Waves, and Air-sea Roughness

    Science.gov (United States)

    Garfinkel, Chaim I.; Oman, Luke David; Barnes, Elizabeth A.; Waugh, Darryn W.; Hurwitz, Margaret H.; Molod, Andrea M.

    2013-01-01

    A robust connection between the drag on surface-layer winds and the stratospheric circulation is demonstrated in NASA's Goddard Earth Observing System Chemistry-Climate Model (GEOSCCM). Specifically, an updated parameterization of roughness at the air-sea interface, in which surface roughness is increased for moderate wind speeds (4ms to 20ms), leads to a decrease in model biases in Southern Hemispheric ozone, polar cap temperature, stationary wave heat flux, and springtime vortex breakup. A dynamical mechanism is proposed whereby increased surface roughness leads to improved stationary waves. Increased surface roughness leads to anomalous eddy momentum flux convergence primarily in the Indian Ocean sector (where eddies are strongest climatologically) in September and October. The localization of the eddy momentum flux convergence anomaly in the Indian Ocean sector leads to a zonally asymmetric reduction in zonal wind and, by geostrophy, to a wavenumber-1 stationary wave pattern. This tropospheric stationary wave pattern leads to enhanced upwards wave activity entering the stratosphere. The net effect is an improved Southern Hemisphere vortex: the vortex breaks up earlier in spring (i.e., the spring late-breakup bias is partially ameliorated) yet is no weaker in mid-winter. More than half of the stratospheric biases appear to be related to the surface wind speed biases. As many other chemistry climate models use a similar scheme for their surface layer momentum exchange and have similar biases in the stratosphere, we expect that results from GEOSCCM may be relevant for other climate models.

  14. CONSTRAINTS ON THE PHYSICAL PROPERTIES OF MAIN BELT COMET P/2013 R3 FROM ITS BREAKUP EVENT

    Energy Technology Data Exchange (ETDEWEB)

    Hirabayashi, Masatoshi; Sánchez, Diego Paul; Gabriel, Travis [Aerospace Engineering Sciences, 429 UCB, University of Colorado, Boulder, CO 80309-5004 United States (United States); Scheeres, Daniel J., E-mail: masatoshi.hirabayashi@colorado.edu [Aerospace Engineering Sciences, 429 UCB, University of Colorado, Boulder, CO 80309-0429 United States (United States)

    2014-07-01

    Jewitt et al. recently reported that main belt comet P/2013 R3 experienced a breakup, probably due to rotational disruption, with its components separating on mutually hyperbolic orbits. We propose a technique for constraining physical properties of the proto-body, especially the initial spin period and cohesive strength, as a function of the body's estimated size and density. The breakup conditions are developed by combining mutual orbit dynamics of the smaller components and the failure condition of the proto-body. Given a proto-body with a bulk density ranging from 1000 kg m{sup –3} to 1500 kg m{sup –3} (a typical range of the bulk density of C-type asteroids), we obtain possible values of the cohesive strength (40-210 Pa) and the initial spin state (0.48-1.9 hr). From this result, we conclude that although the proto-body could have been a rubble pile, it was likely spinning beyond its gravitational binding limit and would have needed cohesive strength to hold itself together. Additional observations of P/2013 R3 will enable stronger constraints on this event, and the present technique will be able to give more precise estimates of its internal structure.

  15. A proxy record of winter temperatures since 1836 from ice freeze-up/breakup in lake Naesijaervi, Finland

    Energy Technology Data Exchange (ETDEWEB)

    Mudelsee, Manfred [Climate Risk Analysis, Hannover (Germany); Alfred Wegener Institute for Polar and Marine Research, Bremerhaven (Germany)

    2012-04-15

    One obstacle on the way to a comprehensive spatial reconstruction of regional temperature changes over the past centuries is the sparseness of long winter temperature records. This paper reconstructs a proxy record of April and November-December temperatures in south-central Finland for the interval from 1836 to 1872 from breakup and freeze-up dates and ice-cover duration of a lake. Emphasis is on detecting the suitable winter months and quantifying the calibrations with measured temperatures (1873-2002). The calibration slope for the breakup date (0.158 C/day) is larger than for freeze-up date (0.119 C/day) or duration (0.090 C/day). A comparison with results from other proxy records shows that the slope may depend also on the geographical site. Trend analyses of the full temperature records (1836-2002) indicate the existence of minor change-points at around 1867 (April temperature) and 1874 (November-December temperature), with warming rates thereafter of 1.67 C per century (April) and 1.16 C per century (November-December). Spectral analyses reveal peaks in the band between 2 and 5 year period, which may point to influences of the North Atlantic Oscillation, and less power in the decadal band (up to 42 year period). (orig.)

  16. Estimating Arctic sea-ice freeze-up and break-up from the satellite record: A comparison of different approaches in the Chukchi and Beaufort Seas

    Directory of Open Access Journals (Sweden)

    Mark Johnson

    2016-09-01

    Full Text Available 1. Abstract The recognized importance of the annual cycle of sea ice in the Arctic to heat budgets, human behavior, and ecosystem functions, requires consistent definitions of such key events in the ice cycle as break-up and freeze-up. An internally consistent and reproducible approach to characterize the timing of these events in the annual sea-ice cycle is described. An algorithm was developed to calculate the start and end dates of freeze-up and break-up and applied to time series of satellite-derived sea-ice concentration from 1979 to 2013. Our approach builds from discussions with sea-ice experts having experience observing and working on the sea ice in the Bering, Chukchi and Beaufort Seas. Applying the algorithm to the 1979–2013 satellite data reveals that freeze-up is delayed by two weeks per decade for the Chukchi coast and one week per decade for the Beaufort coast. For both regions, break-up start is arriving earlier by 5–7 days per decade and break-up end is arriving earlier by 10–12 days per decade. In the Chukchi Sea, “early” break-up is arriving earlier by one month over the 34-year period and alternates with a “late” break-up. The calculated freeze-up and break-up dates provide information helpful to understanding the dynamics of the annual sea-ice cycle and identifying the drivers that modify this cycle. The algorithm presented here, and potential refinements, can help guide future work on changes in the seasonal cycle of sea ice. The sea-ice phenology of freeze-up and break-up that results from our approach is consistent with observations of sea-ice use. It may be applied to advancing our understanding and prediction of the timing of seasonal navigation, availability of ice as a biological habitat, and assessment of numerical models.

  17. Estimating Arctic sea-ice freeze-up and break-up from the satellite record: A comparison of different approaches in the Chukchi and Beaufort Seas

    OpenAIRE

    Mark Johnson; Hajo Eicken

    2016-01-01

    1. Abstract The recognized importance of the annual cycle of sea ice in the Arctic to heat budgets, human behavior, and ecosystem functions, requires consistent definitions of such key events in the ice cycle as break-up and freeze-up. An internally consistent and reproducible approach to characterize the timing of these events in the annual sea-ice cycle is described. An algorithm was developed to calculate the start and end dates of freeze-up and break-up and applied to time series of satel...

  18. Total kinetic energy distribution of fission fragments in 6,7Li + 238U reactions

    International Nuclear Information System (INIS)

    The shape and width of fission-fragment (FF) mass and kinetic energy distribution provides a lot of information on the fission reaction mechanism and the structure of the compound nucleus (CN), the fragments as well as the interacting nuclei. The shape of the mass distribution of the fission fragments for the actinides induced by the proton or neutron is known to change with the incident energy. At low energies, it shows a double humped distribution which changes slowly to a single humped distribution as energy increases. However, for a reaction involving a weakly bound projectile (i.e., 6Li + 232Th), a sharp change in the shape of the mass distribution with energy was observed. The sharp increase in the peak to valley ratio (P:V) in the fission-fragment mass distribution in 6Li + 232Th reaction by Itkis et al. and in 6,7Li + 238U reactions by Santra et al. was concluded to be due to the reduced energy transfer to the composite system caused by incomplete fusion (ICF) of alpha or deuteron/triton followed by fissions. Total Kinetic Energy (TKE) distribution of fission fragments is another important observable on which the effect of projectile breakup is not explored yet. In this contribution, the study of breakup/transfer effect on average TKE distribution for 6,7Li + 238U reactions is presented

  19. Extracting nuclear sizes of medium to heavy nuclei from total reaction cross sections

    Science.gov (United States)

    Horiuchi, W.; Hatakeyama, S.; Ebata, S.; Suzuki, Y.

    2016-04-01

    Background: Proton and neutron radii are fundamental quantities of atomic nuclei. To study the sizes of short-lived unstable nuclei, there is a need for an alternative to electron scattering. Purpose: The recent paper by Horiuchi et al. [Phys. Rev. C 89, 011601(R) (2014)], 10.1103/PhysRevC.89.011601 proposed a possible way of extracting the matter and neutron-skin thickness of light- to medium-mass nuclei using total reaction cross section, σR. The analysis is extended to medium to heavy nuclei up to lead isotopes with due attention to Coulomb breakup contributions as well as density distributions improved by paring correlation. Methods: We formulate a quantitative calculation of σR based on the Glauber model including the Coulomb breakup. To substantiate the treatment of the Coulomb breakup, we also evaluate the Coulomb breakup cross section due to the electric dipole field in a canonical-basis-time-dependent-Hartree-Fock-Bogoliubov theory in the three-dimensional coordinate space. Results: We analyze σR's of 103 nuclei with Z =20 , 28, 40, 50, 70, and 82 incident on light targets, H,21, 4He, and 12C. Three kinds of Skyrme interactions are tested to generate those wave functions. To discuss possible uncertainty due to the Coulomb breakup, we examine its dependence on the target, the incident energy, and the Skyrme interaction. The proton is a most promising target for extracting the nuclear sizes as the Coulomb excitation can safely be neglected. We find that the so-called reaction radius, aR=√{σR/π } , for the proton target is very well approximated by a linear function of two variables, the matter radius and the skin thickness, in which three constants depend only on the incident energy. We quantify the accuracy of σR measurements needed to extract the nuclear sizes. Conclusions: The proton is the best target because, once the incident energy is set, its aR is very accurately determined by only the matter radius and neutron-skin thickness. If σR's at

  20. Breakup of 33.4 MeV/u 17N on a 9Be Target

    Institute of Scientific and Technical Information of China (English)

    HUA Hui; GUO Zhong-Yan; LI Zu-Yu; WANG Hong-Wei; WANG Su-Fang; JIANG Dong-Xing; LI Xiang-Qing; QIAN Tao; WU He-Yu; JIN Gen-Ming; ZHAN Wen-Long; DUAN Li-Min; XIAO Zhi-Guang

    2000-01-01

    Correlation measurements of neutrons and fragments have been performed in a reaction of 33.4 MeV/u 17 N on a 9Be target. Energy spectra of n and nitrogen fragments were obtained at different angles. Based on the nuclear diffraction dissociation model, the measured energy spectra and the neutron angular distributions werereproduced quite well assuming that 1 7 N was composed of 16 N and n or 15 N and 2n interacting with the nonlocal separable potential. The satisfactory agreement between the heoretical calculations and the experimental data shows that the contribution of Coulomb dissociation is negligible in the reaction concerned.

  1. Inclusive Proton Energy Spectra of the Deuteron Induced Reaction

    Institute of Scientific and Technical Information of China (English)

    WANG Jia; YE Tao1; SUN Wei-Li; Yukinobu Watanabe; Kazuyuki Ogata

    2011-01-01

    The continuum-discritized coupled channel method and the glauber model are applied for the description of deuteron elastic breakup and the stripping processes, respectively. Combined with the conventional two-component exciton model for pre-equilibrium processes and the Hauser-Feshbach theory for compound process, an approach based on models is proposed to analyze the inclusive proton energy spectra of a deuteron-induced reaction. The contributions from each process to the energy spectra of the 58Ni(d,xp) reaction are quantitatively given. The results show that this approach is able to reasonably reproduce the experimental data of the double differential cross sections, energy spectra and cross sections, although further improvements are needed.We report the latest research development of vertical buffered electropolishing on its post-treatment procedure as well as the effects of several major post-treatment techniques for buffered electropolishing (BEP) processed 1.5 GHz niobium (Nb) superconducting radio frequency (SRF) cavities. With the established post-treatment procedure, an accelerating gradient of 28.4MV/m is obtained on a single cell cavity of the cebaf shape. This is the best result in the history of BEP development. The cavity is limited by quench with a high quality factor over 1.2×1010 at the quench point. Analyses from optical inspection and temperature-mapping show that the quench should be originated from the pits that were already present on the cavity before this BEP treatment. All of these factors indicate that this procedure will have a great potential to produce better results if cavities without intrinsic performance limiting imperfections are used.%The continuum-discritized coupled channel method and the glauber model are applied for the description of deuteron elastic breakup and the stripping processes,respectively.Combined with the conventional two-component exciton model for pre-equilibrium processes and the Hauser-Feshbach theory for

  2. The Effect of Temperature Dependent Rheology on a Kinematic Model of Continental Breakup and Rifted Continental Margin Formation

    Science.gov (United States)

    Tymms, V. J.; Kusznir, N. J.

    2004-12-01

    The effect of temperature dependent rheology has been examined for a model of continental lithosphere thinning by an upwelling divergent flow field within continental lithosphere and asthenosphere leading to continental breakup and rifted continental margin formation. The model uses a coupled FE fluid flow and thermal solution and is kinematically driven using a half divergence rate Vx and upwelling velocity Vz. Viscosity structure is modified by the evolving temperature field of the model through the temperature dependent Newtonian rheology. Continental lithosphere and asthenosphere material are advected by the fluid-flow field in order to predict crustal and mantle lithosphere thinning leading to rifted continental margin formation. The results of the temperature dependent rheology model are compared with those of a simple isoviscous model. The temperature dependent rheology model predicts continental lithosphere thinning and depth dependent stretching, similar to that predicted by the uniform viscosity model. However compared with the uniform viscosity model the temperature dependent rheology predicts greater amounts of thinning of the continental crust and lithospheric mantle than the isoviscous solutions. An important parameter within the kinematic model of continental lithosphere breakup and rifted continental margin development is the velocity ratio Vz/Vx. For non-volcanic margins, Vz/Vx is thought to be around unity. Applying a velocity ratio Vz/Vx of unity gives a diffuse ocean-continent transition and exhumation of continental lithospheric mantle. For volcanic margins, Vz/Vx is of order 10, falling to unity with a half-life of order 10 Ma, leading to a more sharply defined ocean-continent transition. While Vx during continental breakup may be estimated, Vz can only be inferred. FE fluid flow solutions, in which Vz is not imposed and without an initial buoyancy driven flow component, predict a velocity ratio Vz/Vx of around unity for both temperature

  3. Effects of earlier sea ice breakup on survival and population size of polar bears in western Hudson Bay

    Science.gov (United States)

    Regehr, E.V.; Lunn, N.J.; Amstrup, Steven C.; Stirling, I.

    2007-01-01

    Some of the most pronounced ecological responses to climatic warming are expected to occur in polar marine regions, where temperature increases have been the greatest and sea ice provides a sensitive mechanism by which climatic conditions affect sympagic (i.e., with ice) species. Population-level effects of climatic change, however, remain difficult to quantify. We used a flexible extension of Cormack-Jolly-Seber capture-recapture models to estimate population size and survival for polar bears (Ursus maritimus), one of the most ice-dependent of Arctic marine mammals. We analyzed data for polar bears captured from 1984 to 2004 along the western coast of Hudson Bay and in the community of Churchill, Manitoba, Canada. The Western Hudson Bay polar bear population declined from 1,194 (95% CI = 1,020-1,368) in 1987 to 935 (95% CI = 794-1,076) in 2004. Total apparent survival of prime-adult polar bears (5-19 yr) was stable for females (0.93; 95% CI = 0.91-0.94) and males (0.90; 95% CI = 0.88-0.91). Survival of juvenile, subadult, and senescent-adult polar bears was correlated with spring sea ice breakup date, which was variable among years and occurred approximately 3 weeks earlier in 2004 than in 1984. We propose that this correlation provides evidence for a causal association between earlier sea ice breakup (due to climatic warming) and decreased polar bear survival. It may also explain why Churchill, like other communities along the western coast of Hudson Bay, has experienced an increase in human-polar bear interactions in recent years. Earlier sea ice breakup may have resulted in a larger number of nutritionally stressed polar bears, which are encroaching on human habitations in search of supplemental food. Because western Hudson Bay is near the southern limit of the species' range, our findings may foreshadow the demographic responses and management challenges that more northerly polar bear populations will experience if climatic warming in the Arctic continues as

  4. Pre-breakup magmatism on the Vøring Margin: Insight from new sub-basalt imaging and results from Ocean Drilling Program Hole 642E

    NARCIS (Netherlands)

    Abdelmalak, M.m.; Meyer, R.; Planke, S.; Faleide, J.i.; Gernigon, L.; Frieling, J.; Sluijs, A.; Reichart, G.-J.; Zastrozhnov, D.; Theissen-krah, S.; Said, A.; Myklebust, R.

    2016-01-01

    Improvements in sub-basalt imaging combined with petrological and geochemical observations from the Ocean Drilling Program (ODP) Hole 642E core provide new constraints on the initial breakup processes at the Vøring Margin. New and reprocessed high-quality seismic data allow us to identify a new seis

  5. Pre-breakup magmatism on the Vexing Margin: Insight from new sub-basalt imaging and results from Ocean Drilling Program Hole 642E

    NARCIS (Netherlands)

    Abdelmalak, M.M.; Meyer, R.; Planke, S.; Faleide, J.I.; Gernigon, L.; Frieling, J.; Sluijs, A.; Reichart, G.-J.; Zastrozhnov, D.; Theissen-Krah, S.; Said, A.; Myklebust, R.

    2016-01-01

    Improvements in sub-basalt imaging combined with petrological and geochemical observations from the Ocean Drilling Program (ODP) Hole 642E core provide new constraints on the initial breakup processes at the Vøring Margin. New and reprocessed high-quality seismic data allow us to identify a new seis

  6. Properties of middle-late Proterozoic volcanic rocks in South Qinling and the Precambrian continental break-up

    Institute of Scientific and Technical Information of China (English)

    夏林圻; 夏祖春; 徐学义

    1996-01-01

    In South Qinling, the volcanic series of the middle-late Proterozoic Yunxi Group, Yaolinghe Group, Xi.xiang Group and Bikou Group have characteristics of the continental rift volcanic rocks or continental flood basalts and are formed in continental intraplate tensional setting. The enrichment of incompatible elements, high εNd values and low-medium 87Sr/86Sr initial ratios of these volcanic rocks indicate that they were derived from asthenospheric plume. Under the action of the intense pull-apart in lithosphere, the mantle plume upwelled, quickly decompressed and melted, and finally produced magma. This tensional process made the continental crust break and eventually led to an oceanic basin in late Proterozoic. The middle-late Proterozoic volcanism is a precursor of Precarabrian continental break-up in the South Qinling.

  7. Break-up Process of Perturbed Molten Metal Jet and Preparation of Lead-Free Solder Balls

    Institute of Scientific and Technical Information of China (English)

    He Lijun; Zhang Shuguang; Zhang Shaoming; Xu Jun; Shi Likai

    2004-01-01

    Solder balls, which are used in advanced electronics packages such as BGA (Ball Grid Array) and CSP (Chip Scale Package) to substitute the leads and realize the electrical and mechanical connections between substrate and chip,have severe specifications in diameter tolerance, roundness and surface quality, and therefore challenge the traditional technologies for fabrication of metallic particles and powders. The present work made a survey of perturbed molten metal jet break-up process, observed the formation and growth of capillary wave of tin-lead melt jet by way of rapid solidification, and on the basis of the above research, successfully obtained tin-lead eutectic and Sn-4.0Ag-0.5Cu lead free solder balls with tight distribution and good sphericity of particles through optimization of processing parameters, forming a solid base for cost effectively producing solder balls.

  8. Kinematically complete measurements of the break-up of 6Li using the magnetic spectrograph 'Little John'

    International Nuclear Information System (INIS)

    This report describes set-up and application of an extended detection system for the magnetic spectrograph 'Little John'. The set-up is used in experiments of the Coulomb induced break-up of 6Li into α-particles and deuterons at the Karlsruhe Isochronous Cyclotron for the detection of both coincidence fragments. In first measurements the properties of the detection system are explored. It is shown that the extension provides an increased efficiency, simultaneously maintaining the angular resolution. This is achieved by a direct measurement of both particle trajectories and by an off-line subdivision of the solid angle acceptance. The differential cross sections obtained in this way are in a good agreement with known results and are completing the experimental information. (orig.)

  9. Development and validation of bubble breakup and coalescence constitutive models for the one-group interfacial area transport equation

    Energy Technology Data Exchange (ETDEWEB)

    Pellacani, Filippo

    2012-12-04

    A local mechanistic model for bubble coalescence and breakup for the one-group interfacial area transport equation has been developed, in agreement and within the limits of the current understanding, based on an exhaustive survey of the theory and of the state of the art models for bubble dynamics simulation. The new model has been tested using the commercial 3D CFD code ANSYS CFX. Upward adiabatic turbulent air-water bubbly flow has been simulated and the results have been compared with the data obtained in the experimental facility PUMA. The range of the experimental data available spans between 0.5 to 2 m/s liquid velocity and 5 to 15 % volume fraction. For the implementation of the models, both the monodispersed and the interfacial area transport equation approaches have been used. The first one to perform a detailed analysis of the forces and models to reproduce the dynamic of the dispersed phase adequately and to be used in the next phases of the work. Also two different bubble induced turbulence models have been tested to consider the effect of the presence of the gas phase on the turbulence of the liquid phase. The interfacial area transport equation has been successfully implemented into the CFD code and the state of the art breakup and coalescence models have been used for simulation. The limitations of the actual theory have been shown and a new bubble interactions model has been developed. The simulations showed that a considerable improvement is achieved if compared to the state of the art closure models. Limits in the implementation derive from the actual understanding and formulation of the bubbly dynamics. A strong dependency on the interfacial non-drag force models and coefficients have been shown. More experimental and theory work needs to be done in this field to increase the prediction capability of the simulation tools regarding the distribution of the phases along the pipe radius.

  10. Development and validation of bubble breakup and coalescence constitutive models for the one-group interfacial area transport equation

    International Nuclear Information System (INIS)

    A local mechanistic model for bubble coalescence and breakup for the one-group interfacial area transport equation has been developed, in agreement and within the limits of the current understanding, based on an exhaustive survey of the theory and of the state of the art models for bubble dynamics simulation. The new model has been tested using the commercial 3D CFD code ANSYS CFX. Upward adiabatic turbulent air-water bubbly flow has been simulated and the results have been compared with the data obtained in the experimental facility PUMA. The range of the experimental data available spans between 0.5 to 2 m/s liquid velocity and 5 to 15 % volume fraction. For the implementation of the models, both the monodispersed and the interfacial area transport equation approaches have been used. The first one to perform a detailed analysis of the forces and models to reproduce the dynamic of the dispersed phase adequately and to be used in the next phases of the work. Also two different bubble induced turbulence models have been tested to consider the effect of the presence of the gas phase on the turbulence of the liquid phase. The interfacial area transport equation has been successfully implemented into the CFD code and the state of the art breakup and coalescence models have been used for simulation. The limitations of the actual theory have been shown and a new bubble interactions model has been developed. The simulations showed that a considerable improvement is achieved if compared to the state of the art closure models. Limits in the implementation derive from the actual understanding and formulation of the bubbly dynamics. A strong dependency on the interfacial non-drag force models and coefficients have been shown. More experimental and theory work needs to be done in this field to increase the prediction capability of the simulation tools regarding the distribution of the phases along the pipe radius.

  11. Revisit of Melt Jet Breakup Length Correlations for Fuel-Coolant Interactions: Preliminary Experiment Results in the MATE Facility

    Energy Technology Data Exchange (ETDEWEB)

    Jung, Woo Hyun; Moriyama, Kiyofumi; Park, Hyun Sun [POSTECH, Pohang (Korea, Republic of)

    2015-10-15

    Technical need on the prediction capability for key phenomena in the severe accident scenario is becoming more and more important. Thought severe accident scenarios are in a vast spectrum, the key factor of the accident progression or termination is the behavior of the molten and relocated core material. In the late phase, after a large amount of the core melt is accumulated in the lower head of the reactor vessel, the scenario becomes rather simple and the cooling of the melt in the vessel or in the reactor cavity is the primary issue. Unless so called dry-cavity strategy is taken, the reactor cavity is likely to have water, and the molten core drops into a water pool in the reactor cavity. After ejection from the reactor vessel, the melt jet penetrates water and the fuel-coolant interaction (FCI) occurs. The FCI can be in two specific modes, energetic steam explosions or mild interactions. In this work, we focus on the latter. Depending on the cooling behavior during the sedimentation and after settlement as a debris bed, stable cooling of the debris or re-melting due to the decay heat may occur. In the case of hindered cooling and re-melting, ablation of the concrete base mat, so called molten core-concrete interaction (MCCI) is concerned. From the preliminary test, we got the image data and analyzed it. Through image processing technique, we can distinguish the melt jet and particles, and can get the jet breakup length data. The obtained jet breakup length follows Saito's correlation. Through the preliminary test, a lack of light was verified. Doing image processing, some difficulties occurred due to the trouble with distinguishing the jet and particles. Also, as a next task, distinguishing vapor film and liquid jet will be conducted.

  12. Complete and incomplete fusion cross sections for 6Li+209Bi reaction in multi-body classical molecular dynamical model

    International Nuclear Information System (INIS)

    Using the multi-body Classical Molecular Dynamics simulation of 6Li+209Bi reaction it is shown that: (i) the breakup of a projectile fragment near the barrier leads to substantial increase in the ICF probabilities; (ii) the expected increase in σCF on relaxation of the rigid-body (RB) constraint on the projectile is compensated by reduction in the flux leading to CF, due to ICF events; (iii) the breakup probability increases with ECM and, for given ECM it also increases as b increases and peaks around some b>0, while cross sections σCF and σTF were calculated for b=0 only Therefore, we present the results of σCF (Complete Fusion) and σTF (Total Fusion) calculations which are obtained at critical impact parameter, bcr, where many ICF channels open up and compare with the calculations performed at b=0 only, where only few ICF channels open up

  13. Department of Nuclear Reactions: Overview

    International Nuclear Information System (INIS)

    (full text) During the last year our activities were spread over the three major domains: nuclear, atomic and material physics. The nuclear physics experimental programme covered a broad range of nuclear reactions induced by light and heavy ions. New experiments were performed at the compact C-30 cyclotron at Swierk, at University of Jyvaeskylae, GSI Darmstadt, LN Saturne. Prospects for future experiments on nucleon structure at Forschungszentrum Juelich were open. The collaboration with INR Kiev was tightened and work was done in order to prepare experiments at the C-200 heavy ion cyclotron in Warsaw. An effort to install the ion guide isotope separator on line (IGISOL) at the C-200 cyclotron has also to be mentioned A half a year stay of Dr. Nicholas Keeley in the Department, who received The Royal Society/Polish Academy of Science grant, resulted in many interesting results on breakup of light nuclei. Details can be found in the short abstracts presented in this report. As far as atomic physics is concerned, the activity of a group lead by Prof. Marian Jaskola yielded various new results. The experiments were performed at the University of Erlangen, in close collaboration with the Pedagogical University in Kielce and the University of Basel. Fast neutrons generated in the 3H(d,n)4He reaction induced by the 2 MeV deuteron beam from the Van der Graaff accelerator at the Department were used to calibrate solid state-nuclear-track detectors. This was a very good year for material physics research: Jan Kaczanowski and Slawomir Kwiatkawski received Ph.D. degrees based on dissertation research performed in the material physics research programme, while Pawel Kolodziej completed his MSc. thesis in collaboration with the Institute of Electronic Materials Technology in Warsaw, Research Center Karlsruhe, University of Jena and CSNSM Orsay many results were obtained. Lech Nowicki and Prof. Andrzej Turos were awarded by the Director of the IPJ prizes for their scientific

  14. Chain reaction

    International Nuclear Information System (INIS)

    Chain Reaction is a work of recent American political history. It seeks to explain how and why America came to depend so heavily on its experts after World War II, how those experts translated that authority into political clout, and why that authority and political discretion declined in the 1970s. The author's research into the internal memoranda of the Atomic Energy Commission substantiates his argument in historical detail. It was not the ravages of American anti-intellectualism, as so many scholars have argued, that brought the experts back down to earth. Rather, their decline can be traced to the very roots of their success after World War II. The need to over-state anticipated results in order to garner public support, incessant professional and bureaucratic specialization, and the sheer proliferation of expertise pushed arcane and insulated debates between experts into public forums at the same time that a broad cross section of political participants found it easier to gain access to their own expertise. These tendencies ultimately undermined the political influence of all experts. (author)

  15. A Note on the Kinetics of Diffusion-mediated Reactions

    CERN Document Server

    Naqvi, K Razi

    2014-01-01

    The prevalent scheme of a diffusion-mediated bimolecular reaction $A+B\\rightarrow P$ is an adaptation of that proposed by Briggs and Haldane for enzyme action [{\\em Biochem J.\\/}, 19:338--339, 1925]. The purpose of this Note is to explain, {\\em by using an argument involving no mathematics\\/}, why the breakup of the encounter complex cannot be described, except in special circumstances, in terms of a first-order process $\\{AB\\}\\rightarrow A+B$. Briefly, such a description neglects the occurrence of re-encounters, which lie at the heart of Noyes's theory of diffusion-mediated reactions. The relation $k=\\alpha k_{\\mbox{\\scriptsize e}}$ becomes valid only when $\\alpha$ (the reaction probability per encounter) is very much smaller than unity (activation-controlled reactions), or when $\\beta$ (the re-encounter probability) is negligible (as happens in a gas-phase reaction). References to some works (by the author and his collaborators) which propound the correct approach for finding $k$ are also supplied.

  16. Nuclear fragmentation reactions in extended media studied with Geant4 toolkit

    CERN Document Server

    Pshenichnov, Igor; Mishustin, Igor; Greiner, Walter

    2009-01-01

    It is well known from numerous experiments that nuclear multifragmentation is a dominating mechanism for production of intermediate-mass fragments in nucleus-nucleus collisions at energies above 100 A MeV. In this paper we investigate the validity and performance of the Fermi break-up model and the statistical multifragmentation model implemented as parts of the Geant4 toolkit. We study the impact of violent nuclear disintegration reactions on the depth-dose profiles and yields of secondary fragments for beams of light and medium-weight nuclei propagating in extended media. Implications for ion-beam cancer therapy and shielding from cosmic radiation are discussed.

  17. Spectator matter fragmentation in Au+Au reactions: Phase space analysis

    CERN Document Server

    Vermani, Yogesh K

    2011-01-01

    Clusterization in phase space has been analyzed for peripheral Au+Au reactions at 1000 AMeV using simulated annealing clusterization algorithm (SACA). We investigate how these fragments are correlated in phase space and compare our model calculations with minimum spanning tree (MST) method. Our theoretical study highlights the importance of binding energy criterion in recognizing the fragment structure. MST method however, fails to break-up the spectator matter effectively and thus under-estimates the multiplicity of intermediate mass fragments (IMFs).

  18. Visualization of Atomization Gas Flow and Melt Break-up Effects in Response to Nozzle Design

    Energy Technology Data Exchange (ETDEWEB)

    Anderson, Iver; Rieken, Joel; Meyer, John; Byrd, David; Heidloff, Andy

    2011-04-01

    Both powder particle size control and efficient use of gas flow energy are highly prized goals for gas atomization of metal and alloy powder to minimize off-size powder inventory (or 'reverb') and excessive gas consumption. Recent progress in the design of close-coupled gas atomization nozzles and the water model simulation of melt feed tubes were coupled with previous results from several types of gas flow characterization methods, e.g., aspiration measurements and gas flow visualization, to make progress toward these goals. Size distribution analysis and high speed video recordings of gas atomization reaction synthesis (GARS) experiments on special ferritic stainless steel alloy powders with an Ar+O{sub 2} gas mixture were performed to investigate the operating mechanisms and possible advantages of several melt flow tube modifications with one specific gas atomization nozzle. In this study, close-coupled gas atomization under closed wake gas flow conditions was demonstrated to produce large yields of ultrafine (dia.<20 {mu}m) powders (up to 32%) with moderate standard deviations (1.62 to 1.99). The increased yield of fine powders is consistent with the dual atomization mechanisms of closed wake gas flow patterns in the near-field of the melt orifice. Enhanced size control by stabilized pre-filming of the melt with a slotted trumpet bell pour tube was not clearly demonstrated in the current experiments, perhaps confounded by the influence of the melt oxidation reaction that occurred simultaneously with the atomization process. For this GARS variation of close-coupled gas atomization, it may be best to utilize the straight cylindrical pour tube and closed wake operation of an atomization nozzle with higher gas mass flow to promote the maximum yields of ultrafine powders that are preferred for the oxide dispersion strengthened alloys made from these powders.

  19. Trojan Horse particle invariance for 2H(d,p3H reaction: a detailed study

    Directory of Open Access Journals (Sweden)

    Pizzone R.G.

    2014-03-01

    Full Text Available In the last decades the Trojan Horse method has played a crucial role for the measurement of several charged particle induced reactions cross sections of astrophysical interest. To better understand its cornerstones and its applications to physical cases many tests were performed to verify all its properties and the possible future perspectives. The Trojan Horse nucleus invariance for the binary d(d,pt reaction was therefore tested using the quasi free 2H(6Li, pt4He and 2H(3He,ptH reactions after 6Li and 3He break-up, respectively. The astrophysical S(E-factor for the d(d,pt binary process was then extracted in the framework of the Plane Wave Approximation applied to the two different break-up schemes. The obtained results are compared with direct data as well as with previous indirect investigations. The very good agreement confirms the applicability of the plane wave approximation and suggests the independence of binary indirect cross section on the chosen Trojan Horse nucleus also for the present case.

  20. Trojan Horse particle invariance for 2H(d,p)3H reaction: a detailed study

    Science.gov (United States)

    Pizzone, R. G.; Spitaleri, C.; Bertulani, C. A.; Mukhamedzhanov, A. M.; Blokhintsev, L.; La Cognata, M.; Lamia, L.; Rinollo, A.; Spartá, R.; Tumino, A.

    2014-03-01

    In the last decades the Trojan Horse method has played a crucial role for the measurement of several charged particle induced reactions cross sections of astrophysical interest. To better understand its cornerstones and its applications to physical cases many tests were performed to verify all its properties and the possible future perspectives. The Trojan Horse nucleus invariance for the binary d(d,p)t reaction was therefore tested using the quasi free 2H(6Li, pt)4He and 2H(3He,pt)H reactions after 6Li and 3He break-up, respectively. The astrophysical S(E)-factor for the d(d,p)t binary process was then extracted in the framework of the Plane Wave Approximation applied to the two different break-up schemes. The obtained results are compared with direct data as well as with previous indirect investigations. The very good agreement confirms the applicability of the plane wave approximation and suggests the independence of binary indirect cross section on the chosen Trojan Horse nucleus also for the present case.

  1. Excitation Functions of Deuteron Induced Nuclear Reactions on Iron

    International Nuclear Information System (INIS)

    The excitation functions were measured for nuclear reactions induced by deuterons on natural iron leading to the production of 52g,54Mn and 55,56,57,58gCo radionuclides in the energy range from threshold energy up to 10 MeV. The measured data were compared with other measured data and also with the results of theoretical calculations using the default parameters of the codes EMPIRE-3.0 and TALYS. The coulomb barrier Bc for iron target was calculated and the excitation curves were discussed taking in consideration the deuteron breakup and the pre-equilibrium emission processes. The integral yields of 55,56,57,58gCO radionuclides were calculated as a function of deuteron energy

  2. Inclusive spectra of stripping reactions induced by heavy ions

    International Nuclear Information System (INIS)

    The spectra of inclusive transfer reactions induced by heavy ions and leading to continuum final states show high-lying broad resonancelike structures superimposed on a large continuum. Recent experimental spectra for neutron stripping on targets in the lead region are analyzed by the Bonaccorso and Brink single-particle transfer model. The results of the calculation suggest that the structures are due to the population of high-spin single-particle states which are unbound and mix with the underlying states giving rise to a broadening of the peak. The main characteristics of the spectra are reproduced. Moreover, an estimate of the elastic and inelastic breakup contributions to the inclusive spectra is given

  3. Comparison of the effects of couplings to breakup channels in reactions induced by {sup 6}Li and {sup 6}He on the same {sup 64}Zn target

    Energy Technology Data Exchange (ETDEWEB)

    Fernández-García, J. P., E-mail: fernandez@lns.infn.it; Di Pietro, A.; Figuera, P.; Fisichella, M. [INFN, Laboratori Nazionali del Sud, via S. Sofia 62, 1-95123 Catania (Italy); Lattuada, M.; Musumarra, A.; Pellegriti, M. G.; Scuderi, V.; Torresi, D. [INFN, Laboratori Nazionali del Sud, via S. Sofia 62, 1-95123 Catania (Italy); Dipartamento di Fisica e Astronomia, via S. Sofia 64, I-95123 Catania (Italy); Moro, A. M. [Departamento de FAMN, Universidad de Sevilla, Apartado 1065, E-41080 Seville (Spain); Zadro, M. [Ruder Bošković Institute, Bijenička cesta 54, HR-10000 Zagreb (Croatia)

    2015-10-15

    The experimental elastic scattering angular distributions for the weakly bound nuclei {sup 6,7}Li and for the halo nucleus {sup 6}He on the same {sup 64}Zn target at several energies around the Coulomb barrier were measured at the Laboratori Nazionali del Sud (LNS, Italy) and at the Cyclotron Research Center, Louvain La Neuve (Belgium), respectively. The measured elastic scattering angular distributions of these three systems at the same center of mass energy have been compared. The experimental data of the {sup 6,7}Li+ {sup 64}Zn systems have been analyzed within the CDCC method, while the {sup 6}He+{sup 64}Zn data have been compared with both both CDCC and CRC calculations.

  4. Design and Fabrication of DebriSat - A Representative LEO Satellite for Improvements to Standard Satellite Breakup Models

    Science.gov (United States)

    Clark, S.; Dietrich, A.; Fitz-Coy, N.; Weremeyer, M.; Liou, J.-C.

    2012-01-01

    This paper discusses the design and fabrication of DebriSat, a 50 kg satellite developed to be representative of a modern low Earth orbit satellite in terms of its components, materials used, and fabrication procedures. DebriSat will be the target of a future hypervelocity impact experiment to determine the physical characteristics of debris generated after an on-orbit collision of a modern LEO satellite. The major ground-based satellite impact experiment used by DoD and NASA in their development of satellite breakup models was SOCIT, conducted in 1992. The target used for that experiment was a Navy transit satellite (40 cm, 35 kg) fabricated in the 1960's. Modern satellites are very different in materials and construction techniques than those built 40 years ago. Therefore, there is a need to conduct a similar experiment using a modern target satellite to improve the fidelity of the satellite breakup models. To ensure that DebriSat is truly representative of typical LEO missions, a comprehensive study of historical LEO satellite designs and missions within the past 15 years for satellites ranging from 1 kg to 5000 kg was conducted. This study identified modern trends in hardware, material, and construction practices utilized in recent LEO missions. Although DebriSat is an engineering model, specific attention is placed on the quality, type, and quantity of the materials used in its fabrication to ensure the integrity of the outcome. With the exception of software, all other aspects of the satellite s design, fabrication, and assembly integration and testing will be as rigorous as that of an actual flight vehicle. For example, to simulate survivability of launch loads, DebriSat will be subjected to a vibration test. As well, the satellite will undergo thermal vacuum tests to verify that the components and overall systems meet typical environmental standards. Proper assembly and integration techniques will involve comprehensive joint analysis, including the precise

  5. The Fragmented Manihiki Plateau - Key Region for Understanding the Break-up of the "Super" Large Igneous Province Ontong Java Nui

    Science.gov (United States)

    Hochmuth, K.; Gohl, K.; Uenzelmann-Neben, G.; Werner, R.

    2014-12-01

    The Manihiki Plateau of the western Pacific is one of the world - wide greatest Large Igneous Province (LIP) on oceanic crust. It is assumed that the Manihiki Plateau was emplaced as the centerpiece of the "Super-LIP" Ontong Java Nui by multiple volcanic phases during the Cretaceous Magnetic Quiet Period. The subsequent break-up of Ontong Java Nui led to fragmentation of the Manihiki Plateau into three sub-plateaus, which all exhibit individual relicts of the "Super-LIP" break-up. We examine two deep crustal seismic refraction/wide-angle reflection profiles crossing the two largest sub-plateaus of the Manihiki Plateau, the Western Plateaus and the High Plateau. Modeling of P- and S-wave velocities reveals surprising differences in the crustal structure between the two sub-plateaus. Whereas the High Plateau shows a constant crustal thickness of 20 km, relicts of multiple volcanic phases and break-up features at its margins, the model of the Western Plateaus reveals a crustal thickness decreasing from 17 km to only 9 km. There is only little evidence of secondary phases of volcanic activity. The main upper crustal structure on the Western Plateaus consists of fault systems and sedimentary basins. We infer that the High Plateau experienced phases of strong secondary volcanism, and that tectonic deformation was limited to its edges. The Western Plateaus, on the contrary, were deformed by crustal stretching and underwent only little to no secondary volcanism. This indicates that the two main sub-plateaus of the Manihiki Plateau experienced a different geological history and have played their individual parts in the break-up history of Ontong Java Nui.

  6. U-Pb zircon geochronology of the Ligurian ophiolites (Northern Apennine, Italy): Implications for continental breakup to slow seafloor spreading

    Science.gov (United States)

    Tribuzio, Riccardo; Garzetti, Fabio; Corfu, Fernando; Tiepolo, Massimo; Renna, Maria Rosaria

    2016-01-01

    Fragments of Jurassic oceanic crust exposed in the Northern Apennine (Italy) are either associated with continental lithosphere material (External Ligurian ophiolites), or bear structural and compositional resemblances to slow spreading ridge crust (Internal Ligurian ophiolites). To acquire new information about the transition from continental breakup to slow seafloor spreading, we carried out a U-Pb geochronological study of zircons from gabbro bodies of both External and Internal Ligurian ophiolites. Zircons were separated from seven samples and analyzed for U-Pb isotopes by laser ablation ICPMS and isotope dilution TIMS. The zircons were also investigated for morphology, internal structures, inclusions and chemistry. These characteristics reveal remarkable similarities to zircons collected from modern oceanic crust. Taken as a whole, the new U-Pb zircon dates obtained for the Ligurian ophiolites range from ~ 165 to ~ 161 Ma, thereby arguing against previous geochronological investigations suggesting a period of ~ 26 Ma for the formation of the Ligurian gabbroic crust. The time interval intervened from onset of gabbroic crust formation to configuration of a "slow spreading ridge type" crust was most likely ≤ 5 Ma. New insights into the opening mechanisms of the fossil, slow seafloor spreading basin are provided.

  7. The initial break-up of Pangæa elicited by Late Palæozoic deglaciation

    Science.gov (United States)

    Yeh, Meng-Wan; Shellnutt, J. Gregory

    2016-08-01

    The break-up of Pangæa was principally facilitated by tensional plate stress acting on pre-existing suture zones. The rifting of Pangæa began during the Early Permian along the southern Tethys margin and produced the lenticular-shaped continent known as Cimmeria. A mantle-plume model is ascribed to explain the rift-related volcanism but the NW-SE oriented Cimmerian rifts do not correlate well with pre-existing suture zones or ‘structural heterogeneities’ but appear to have a pertinent spatial and temporal association with Late Palæozoic glacial-interglacial cycles. Mantle potential temperature estimates of Cimmerian rift-related basalts (1410 °C ± 50 °C) are similar to ambient mantle conditions rather than an active mantle-plume rift as previously suggested. Moreover, we find that the distribution of glacial deposits shows significant temporal and spatial concurrence between the glacial retreat margins and rifting sites. We conclude that the location and timing of Cimmerian rifting resulted from the exploitation of structural heterogeneities within the crust that formed due to repeated glacial-interglacial cycles during the Late Palæozoic. Such effects of continental deglaciation helped to create the lenticular shape of Cimmeria and Neotethys Ocean suggesting that, in some instances, climate change may directly influence the location of rifting.

  8. The initial break-up of Pangæa elicited by Late Palæozoic deglaciation.

    Science.gov (United States)

    Yeh, Meng-Wan; Shellnutt, J Gregory

    2016-01-01

    The break-up of Pangæa was principally facilitated by tensional plate stress acting on pre-existing suture zones. The rifting of Pangæa began during the Early Permian along the southern Tethys margin and produced the lenticular-shaped continent known as Cimmeria. A mantle-plume model is ascribed to explain the rift-related volcanism but the NW-SE oriented Cimmerian rifts do not correlate well with pre-existing suture zones or 'structural heterogeneities' but appear to have a pertinent spatial and temporal association with Late Palæozoic glacial-interglacial cycles. Mantle potential temperature estimates of Cimmerian rift-related basalts (1410 °C ± 50 °C) are similar to ambient mantle conditions rather than an active mantle-plume rift as previously suggested. Moreover, we find that the distribution of glacial deposits shows significant temporal and spatial concurrence between the glacial retreat margins and rifting sites. We conclude that the location and timing of Cimmerian rifting resulted from the exploitation of structural heterogeneities within the crust that formed due to repeated glacial-interglacial cycles during the Late Palæozoic. Such effects of continental deglaciation helped to create the lenticular shape of Cimmeria and Neotethys Ocean suggesting that, in some instances, climate change may directly influence the location of rifting. PMID:27511791

  9. Application of the Trojan Horse Method to study neutron induced reactions: the 17O(n, α14C reaction

    Directory of Open Access Journals (Sweden)

    Gulino M.

    2014-03-01

    Full Text Available The reaction 17O(n, α14C was studied using virtual neutrons coming from the quasi-free deuteron break-up in the three body reaction 17O+d → α+14C+p. This technique, called virtual neutron method, extends the Trojan Horse method to neutron-induced reactions allowing to study the reaction cross section avoiding the suppression effects coming from the penetrability of the centrifugal barrier. For incident neutron energies from thermal up to a few hundred keV, direct experiments have shown the population of two out of three expected excited states at energies 8213 keV and 8282 keV and the influence of the sub-threshold level at 8038 keV. In the present experiment the 18O excited state at E* = 8.125 MeV, missing in the direct measurement, is observed. The angular distributions of the populated resonances have been measured for the first time. The results unambiguously indicate the ability of the method to overcome the centrifugal barrier suppression effect and to pick out the contribution of the bare nuclear interaction.

  10. Application of the Trojan Horse Method to study neutron induced reactions: the 17O(n, α)14C reaction

    Science.gov (United States)

    Gulino, M.; Spitaleri, C.; Tang, X. D.; Guardo, G. L.; Lamia, L.; Cherubini, S.; Bucher, B.; Burjan, V.; Couder, M.; Davies, P.; deBoer, R.; Fang, X.; Goldberg, V. Z.; Hons, Z.; Kroha, V.; Lamm, L.; La Cognata, M.; Li, C.; Ma, C.; Mrazek, J.; Mukhamedzhanov, A. M.; Notani, M.; O'Brien, S.; Pizzone, R. G.; Rapisarda, G. G.; Roberson, D.; Sergi, M. L.; Tan, W.; Thompson, I. J.; Wiescher, M.

    2014-03-01

    The reaction 17O(n, α)14C was studied using virtual neutrons coming from the quasi-free deuteron break-up in the three body reaction 17O+d → α+14C+p. This technique, called virtual neutron method, extends the Trojan Horse method to neutron-induced reactions allowing to study the reaction cross section avoiding the suppression effects coming from the penetrability of the centrifugal barrier. For incident neutron energies from thermal up to a few hundred keV, direct experiments have shown the population of two out of three expected excited states at energies 8213 keV and 8282 keV and the influence of the sub-threshold level at 8038 keV. In the present experiment the 18O excited state at E* = 8.125 MeV, missing in the direct measurement, is observed. The angular distributions of the populated resonances have been measured for the first time. The results unambiguously indicate the ability of the method to overcome the centrifugal barrier suppression effect and to pick out the contribution of the bare nuclear interaction.

  11. Catalysis of Photochemical Reactions.

    Science.gov (United States)

    Albini, A.

    1986-01-01

    Offers a classification system of catalytic effects in photochemical reactions, contrasting characteristic properties of photochemical and thermal reactions. Discusses catalysis and sensitization, examples of catalyzed reactions of excepted states, complexing ground state substrates, and catalysis of primary photoproducts. (JM)

  12. Low-energy nuclear reactions with double-solenoid- based radioactive nuclear beam

    Indian Academy of Sciences (India)

    Valdir Guimarães

    2010-07-01

    The University of Notre Dame, USA (Becchetti et al, Nucl. Instrum. Methods Res. A505, 377 (2003)) and later the University of São Paulo, Brazil (Lichtenthaler et al, Eur. Phys. J. A25, S-01, 733 (2005)) adopted a system based on superconducting solenoids to produce low-energy radioactive nuclear beams. In these systems the solenoids act as thick lenses to collect, select, and focus the secondary beam into a scattering chamber. Many experiments with radioactive light particle beams (RNB) such as 6He, 7Be, 8Li, 8B have been performed at these two facilities. These low-energy RNB have been used to investigate low-energy reactions such as elastic scattering, transfer and breakup, providing useful information on the structure of light nuclei near the drip line and on astrophysics. Total reaction cross-sections, derived from elastic scattering analysis, have also been investigated for light system as a function of energy and the role of breakup of weakly bound or exotic nuclei is discussed.

  13. On thermonuclear reaction rates

    OpenAIRE

    Hans J. Haubold; Mathai, Arak Mathai

    1996-01-01

    Nuclear reactions govern major aspects of the chemical evolution of galaxies and stars. Analytic study of the reaction rates and reaction probability integrals is attempted here. Exact expressions for the reaction rates and reaction probability integrals for nuclear reactions in the cases of nonresonant, modified nonresonant, screened nonresonant and resonant cases are given. These are expressed in terms of H-functions, G-functions and in computable series forms. Computational aspects are als...

  14. Research on the fundamental process of thermal-hydraulic behaviors in severe accident. Breakup and cooling of molten material jets. JAERI's nuclear research promotion program, H10-027-2. Contract research

    International Nuclear Information System (INIS)

    Core melt accidents could lead to the pouring of molten core materials into a body of water accumulating in the reactor lower head in the form of jets with a few centimeters up to a few tens of centimeters. If molten core jets penetrate the body of water without breakup. A poor coolability of the molten core bed would occur, which means the difficulty of maintaining the molten core bed in the reactor vessel. Hence, the breakup mechanism of molten core jets had to be well understood for the evaluation of the coolability of molten core bed. The objective of the present experimental study is to confirm that, even in molten material jets, the breakup of jet originating in the coolant entrained within a molten material jet due to 'the organized motion' between the coolant and the jet, which has been recognized in the field of fluid mechanics, is caused. The first series of experiment was conducted to observe this type of breakup by using molten tin jets up to 25 mm in diameter. Molten tin jet was expected to easily cause this kind of breakup of jet because of a low kinematic viscosity, which means a easy transformation of jet due to the organized motion for the coolant to entrain. The second series of experiment was conducted by using molten copper jet of 25 mm in diameter, of which kinematic viscosity is about same as that of molten UO2. The breakup of jet due to the entrainment of the coolant was observed up to high ambient Weber numbers, which cover the atomization regime. The mechanism of the breakup observed in the present study is able to reasonably explain the apparent difference between the breakup lengths of 150 kg-scale corium jets and the breakup lengths of about 8 kg-scale lead-bismuth alloy jets. The breakup by the mechanism reported here also assures a high coolability of molten jets because of an efficient entrainment of coolant within the jet. (author)

  15. 低温低速烟气中液滴破碎临界韦伯数与破碎时间分析%The Analysis of Critical We and Breakup Time During Breakup of Droplet in Low Temperature and Low Velocity Flue Gas

    Institute of Scientific and Technical Information of China (English)

    张志荣; 冉景煜

    2012-01-01

    应用湍流模型和流体体积模型方法对液滴在低温低速烟气中的破碎特性进行数值研究,重点分析液滴韦伯数和雷诺数对液滴破碎方式的影响,以及烟气密度、流速、液滴速度和粒径等对液滴破碎时间的影响。计算结果表明:对于文中研究的低温低速气体环境及液滴,主要存在液滴发生袋式破碎及没有发生破碎两种形式,临界韦伯数为10.6。韦伯数是液滴破碎的尺度,雷诺数在液滴破碎中不是关键因素。对于文中的气体环境和液滴,综合影响下液滴无量纲破碎时间为常数1,独立于液滴粒径。在文中低温低速气体环境中,将液滴粒径控制在0.3~0.4 mm有助于缩短液滴的完全蒸发时间,提高液滴群蒸发效率。%In this paper,the volume of fluid(VOF)method and a turbulent model were employed to study the character of the drop breakup in the low temperature and low velocity flue gas numerically.The effects of We and Re number on breakup mode were analyzed.The effects of flue gas density and velocity,droplet velocity and diameter on breakup time were also analyzed.The results show that there are two kinds of breakup manner,that are the big breakup process and no breakup process with regard to the gas and droplet studied.The critical Weber number equals to 10.6.In the atmosphere considered,the Weber number is a rule of the droplet breakup,and the Re number is not a critical factor in the process of the liquid drop breakup.Considering the integrated factors,the normalized breakup time of droplet is independent of the droplet diameter,revealing constant 1,within the range of the gas and the droplet studied.In the low temperature and low velocity gas considered,it can conduce to the shorter life time of drop during the evaporation that controls the drop diameter within the range of 0.3~0.4 mm,therefore improving the evaporation efficiency of the drop group.

  16. Production of fast monoenergetic neutrons by charged particle reactions among the hydrogen isotopes. Source properties, experimental techniques and limitations of the data

    International Nuclear Information System (INIS)

    All five reactions 2H(d,n)3He, 1H(t,n)3He, 3H(p,n)3He, 3H(d,n)4He and 2H(t,n)4He are discussed with special emphasis on recent developments and on the higher neutron energy range up to 40 MeV. It is discussed how inclusion of recent data will change previous evaluations of the p-T system at lower energies. Breakup data of all reactions are collected. Experimental techniques and uncertainties of neutron source property measurements are discussed and recommendations for future work are given. (author)

  17. Spectator invariance test in the study of the Trojan Horse Method 6,7Li fusion reactions via the Trojan Horse Method

    OpenAIRE

    Li C; La Cognata M.; Kroha V.; Kiss G.G.; Hons Z.; Cherubini S.; Burjan V.; Blokhintsev L.; Spitaleri C.; Mukhamedzhanov A.; Bertulani C.; Lamia L.; Pizzone R.G.; Mrazek J.; Piskoř S.

    2011-01-01

    Fusion reactions play a crucial role for several astrophysical scenarios. At the low energies typical of such environments direct measurements of reaction cross sections are very difficult, and even sometimes impossible. In such cases the use of indirect methods can give a substantial help. The Trojan Horse Method (THM) is based on the quasi-free break-up of a nucleus, which can be described in terms of a cluster structure. In such applications the independence of THM results with differe...

  18. Discussion on final rifting evolution and breakup : insights from the Mid Norwegian - North East Greenland rifted system

    Science.gov (United States)

    Peron-Pinvidic, Gwenn; Terje Osmundsen, Per

    2016-04-01

    In terms of rifted margin studies, the characteristics of the distal and outer domains are among the today's most debated questions. The architecture and composition of deep margins are rarely well constrained and hence little understood. Except from in a handful number of cases (eg. Iberia-Newfoundland, Southern Australia, Red Sea), basement samples are not available to decipher between the various interpretations allowed by geophysical models. No consensus has been reached on the basement composition, tectonic structures, sedimentary geometries or magmatic content. The result is that non-unique end-member interpretations and models are still proposed in the literature. So, although these domains mark the connection between continents and oceans, and thus correspond to unique stages in the Earth's lithospheric life cycle, their spatial and temporal evolution are still unresolved. The Norwegian-Greenland Sea rift system represents an exceptional laboratory to work on questions related to rifting, rifted margin formation and sedimentary basin evolution. It has been extensively studied for decades by both the academic and the industry communities. The proven and expected oil and gas potentials led to the methodical acquisition of world-class geophysical datasets, which permit the detailed research and thorough testing of concepts at local and regional scales. This contribution is issued from a three years project funded by ExxonMobil aiming at better understanding the crustal-scale nature and evolution of the Norwegian-Greenland Sea. The idea was to take advantage of the data availability on this specific rift system to investigate further the full crustal conjugate scale history of rifting, confronting the various available datasets. In this contribution, we will review the possible structural and sedimentary geometries of the distal margin, and their connection to the oceanic domain. We will discuss the definition of 'breakup' and introduce a first order conceptual

  19. Continental breakup and the dynamics of rifting in back-arc basins: The Gulf of Lion margin

    Science.gov (United States)

    Jolivet, Laurent; Gorini, Christian; Smit, Jeroen; Leroy, Sylvie

    2015-04-01

    Deep seismic profiles and subsidence history of the Gulf of Lion margin reveal an intense stretching of the distal margin and strong postrift subsidence, despite weak extension of the onshore and shallow offshore portions of the margin. We revisit this evolution from the geological interpretation of an unpublished multichannel seismic profile and other published geophysical data. We show that an 80 km wide domain of thin lower continental crust, the "Gulf of Lion metamorphic core complex," is present in the ocean-continent transition zone and exhumed mantle makes the transition with oceanic crust. The exhumed lower continental crust is bounded upward and downward by shallow north dipping detachments. The presence of exhumed lower crust in the deep margin explains the discrepancy between the amount of extension deduced from normal faults in the upper crust and total extension. We discuss the mechanism responsible for exhumation and present two scenarios: the first one involving a simple coupling between mantle extension due to slab retreat and crustal extension and the second one involving extraction of the lower crust and mantle from below the margin by the southeastward flow of hot asthenosphere in the back-arc region during slab rollback. In both scenarios, the combination of Eocene crustal thickening related to the Pyrenees, the nearby volcanic arc, and a shallow lithosphere-asthenosphere boundary weakened the upper mantle and lower crust enough to make them flow southeastward. The overall hot geodynamic environment also explains the subaerial conditions during most of the rifting stage and the delayed subsidence after breakup.

  20. Pre-Gondwanan-breakup origin of Beauprea (Proteaceae) explains its historical presence in New Caledonia and New Zealand.

    Science.gov (United States)

    He, Tianhua; Lamont, Byron B; Fogliani, Bruno

    2016-04-01

    New Caledonia and New Zealand belong to the now largely submerged continent Zealandia. Their high levels of endemism and species richness are usually considered the result of transoceanic dispersal events followed by diversification after they re-emerged from the Pacific Ocean in the mid-Cenozoic. We explore the origin and evolutionary history of Beauprea (Proteaceae), which is now endemic to New Caledonia but was once spread throughout eastern Gondwana, including New Zealand. We review the extensive Beauprea-type pollen data in the fossil records and analyze the relationship of these fossil taxa to extant genera within Proteaceae. We further reconstruct the phylogenetic relations among nine extant species of Beauprea and estimate the age of the Beauprea clade. By incorporating extinct taxa into the Beauprea phylogenetic tree, we reconstruct the ancient distribution of this genus. Our analysis shows that Beauprea originated c. 88 Ma (million years ago) in Antarctica-Southeastern Australia and spread throughout Gondwana before its complete breakup. We propose that Beauprea, already existing as two lineages, was carried with Zealandia when it separated from the rest of Gondwana c. 82 Ma, thus supporting an autochthonous origin for Beauprea species now in New Caledonia and historically in New Zealand up to 1 Ma. We show that the presence of Beauprea through transoceanic dispersal is implausible. This means that neither New Caledonia nor New Zealand has been entirely submerged since the Upper Cretaceous; thus, possible vicariance and allopatry must be taken into account when considering the high levels of endemism and species richness of these island groups. PMID:27386508

  1. Production of energetic light fragments in spallation reactions

    International Nuclear Information System (INIS)

    Different reaction mechanisms contribute to the production of light fragments (LF) from nuclear reactions. Available models cannot accurately predict emission of LF from arbitrary reactions. The cascade-exciton model (CEM) and the Los Alamos version of the quark-gluon string model (LAQGSM), as implemented in the CEM03.03 and LAQGSM03.03 event generators used in the Los Alamos Monte Carlo transport code MCNP6, describe quite well the spectra of fragments with sizes up to 4He across a broad range of target masses and incident energies. However, they do not predict high-energy tails for LF heavier than 4He. The standard versions of CEM and LAQGSM do not account for preequilibrium emission of LF larger than 4He. The aim of our work is to extend the preequilibrium model to include such processes. We do this by including the emission of fragments heavier than 4He at the preequilibrium stage, and using an improved version of the Fermi Break-up model, providing improved agreement with various experimental data

  2. Explicit inclusion of nonlocality in (d,p) transfer reactions

    CERN Document Server

    Titus, L J; Potel, G

    2016-01-01

    Background: Traditionally, nucleon-nucleus optical potentials are made local for convenience. In recent work we studied the effects of including nonlocal interactions explicitly in the final state for (d,p) reactions, within the distorted wave Born approximation. Purpose: Our goal in this work is to develop an improved formalism for nonlocal interactions that includes deuteron breakup and to use it to study the effects of including nonlocal interactions in transfer (d,p) reactions, in both the deuteron and the proton channel. Method: We extend the finite-range adiabatic distorted wave approximation to include nonlocal nucleon optical potentials. We apply our method to (d,p) reactions on 16O, 40Ca, 48Ca, 126Sn, 132Sn, and 208Pb at 10, 20 and 50 MeV. Results: We find that nonlocality in the deuteron scattering state reduces the amplitude of the wave function in the nuclear interior, and shifts the wave function outward. In many cases, this has the effect of increasing the transfer cross section at the first pea...

  3. Production of Energetic Light Fragments in Spallation Reactions

    Directory of Open Access Journals (Sweden)

    Mashnik Stepan G.

    2014-03-01

    Full Text Available Different reaction mechanisms contribute to the production of light fragments (LF from nuclear reactions. Available models cannot accurately predict emission of LF from arbitrary reactions. However, the emission of LF is important formany applications, such as cosmic-ray-induced single event upsets, radiation protection, and cancer therapy with proton and heavy-ion beams, to name just a few. The cascade-exciton model (CEM and the Los Alamos version of the quark-gluon string model (LAQGSM, as implemented in the CEM03.03 and LAQGSM03.03 event generators used in the Los Alamos Monte Carlo transport code MCNP6, describe quite well the spectra of fragments with sizes up to 4He across a broad range of target masses and incident energies. However, they do not predict high-energy tails for LF heavier than 4He. The standard versions of CEM and LAQGSM do not account for preequilibrium emission of LF larger than 4He. The aim of our work is to extend the preequilibrium model to include such processes. We do this by including the emission of fragments heavier than 4He at the preequilibrium stage, and using an improved version of the Fermi Break-up model, providing improved agreement with various experimental data.

  4. Nuclear-reaction studies via the observation of unbound outgoing systems

    Energy Technology Data Exchange (ETDEWEB)

    Bice, A.N.

    1982-01-01

    The mechanisms involved in the production of fast ..cap alpha..-particles in /sup 12/C induced reactions have been investigated for the /sup 12/C + /sup 208/Pb system at bombarding energies of E(/sup 12/C) = 132, 187 and 230 MeV. Absolute cross sections have been determined for the reactions /sup 208/Pb (/sup 12/C, /sup 8/Be (g.s.)), /sup 208/Pb(/sup 12/C, /sup 8/Be (2.94 MeV)) and /sup 208/Pb (/sup 12/C, /sup 12/C* ..-->.. ..cap alpha.. + /sup 8/Be) by double and triple coincidence measurements of the sequential decay ..cap alpha..-particles. Inclusive ..cap alpha..-particle production cross sections were also measured at E (/sup 12/C) = 187 MeV for comparison. It is found that the simple inelastic scattering process (/sup 12/C, /sup 12/C* ..-->.. ..cap alpha.. + /sup 8/Be) does not contribute significantly to the production of fast ..cap alpha..-particles but that the production of /sup 8/Be nuclei by projectile fragmentation is an important source of ..cap alpha..-particles. At the highest bombarding energy investigated (19 MeV/A) it appears that the /sup 12/C ..-->.. 3..cap alpha.. fragmentation reaction becomes more prominent at the expense of the /sup 12/C ..-->.. ..cap alpha.. + /sup 8/Be fragmentation channel. It is concluded that projectile spectroscopic properties and/or final state interactions are important in fragmentation reactions for these bombarding energies. In a kinematically complete experiment the direct and the sequential breakup channels of 10 MeV/A /sup 7/Li projectiles have been investigated with /sup 12/C and /sup 208/Pb targets. By appropriate arrangement of detector telescopes it was possible to define a kinematical window which allowed for the unambigious observation of both the direct (to the ..cap alpha..-t continuum) and the sequential components of a heavy-ion projectile breakup reaction. A semiclassical Monte Carlo type projectile breakup calculation was constructed which qualitatively reproduced the measured ..cap alpha

  5. Influence of margin segmentation and anomalous volcanism upon the break-up of the Hatton Bank rifted margin, west of the UK

    Science.gov (United States)

    Elliott, G. M.; Parson, L. M.

    2007-12-01

    The Hatton Bank margin, flanking the Iceland Basin is a widely cited example of a volcanic rifted margin. Prior to this study insights into the break-up history of the margin have been limited to profiles in the north and south, yet whilst valuable, the along margin tectono-magmatic variability has not been revealed. Over 5660 line km of high quality reflection seismic profiles with supplementary multibeam bathymetry were collected to support the UK's claim to Hatton region under the United Nations Convention on Law of the Sea (UNCLOS). Integration of this new data with existing profiles, allowed the margin to be divided into three segments, each of which are flanked by oceanic crust with a smooth upper surface and internal dipping reflectors. The southernmost segment is characterised by a series of inner and outer seaward dipping reflector (SDR) packages, which are separated by an outer high feature. The outer SDR are truncated by Endymion Spur, a chain of steep sided, late stage volcanic cones linked with necks. The central sector has no inner SDR package and is characterised by the presence of a highly intruded continental block, the Hatton Bank Block (HBB). The northern sector is adjacent to Lousy Bank, with a wider region of SDR recognised than to the south and a high amount of volcanic cones imaged. The variations in the distribution of the SDR's along the margin, the presence of the HBB and Endymion Spur all suggest that the break-up process was not uniform alongstrike. The division of the margin into three sectors reveals that structural segmentation played an important role in producing the variations along the margin. Break- up initiated in the south and progressed north producing the SDR packages witnessed, when the HBB was encountered the focus of break-up moved seaward of the block. The northern sector was closer to the Iceland Hotspot and hence a greater amount of volcanism is encountered. The smooth oceanic basement also indicates a high thermal flux

  6. Practice Gaps: Drug Reactions.

    Science.gov (United States)

    Wolverton, Stephen E

    2016-07-01

    The term "drug reactions" is relevant to dermatology in three categories of reactions: cutaneous drug reactions without systemic features, cutaneous drug reactions with systemic features, and systemic drugs prescribed by the dermatologist with systematic adverse effects. This article uses examples from each of these categories to illustrate several important principles central to drug reaction diagnosis and management. The information presented will help clinicians attain the highest possible level of certainty before making clinical decisions. PMID:27363888

  7. The neutron within the deuteron as a surrogate for neutron-induced reactions

    CERN Document Server

    Bertulani, C A; Hussein, M S; Shubhchintak,; Tran, Viet Nhan Hao

    2016-01-01

    We propose the use of neutron poisons in reactions induced by radioactive beams as a test of theoretical models aiming to relate neutron capture in nuclei with neutron surrogate reactions such as (d,p) reactions. We exploit the approximations necessary to obtain a direct relation between the two reactions; surrogate vs. neutron capture. We also show how this is intimately related to the momentum distribution of the neutron within the deuteron. The models we use are based on the theory of inclusive breakup reactions commonly employed in the treatment of incomplete fusion and surrogate method. Such theories were developed in the 80's by Ichimura, Autern and Vincent [Phys. Rev. C 32, 431 (1985)], Udagawa and Tamura [Phys. Rev. C 24, 1348 (1981)] and Hussein and McVoy [Nucl. Phys. A 445, 124 (1985)]. We use these theories to derive an expression for the proton yield in the reaction A(d,p)B. The capture reaction $n + A \\rightarrow B$ is then extracted using reasonable approximations. By recalling an old method pro...

  8. Entrance channel dependence of back angle yields: orbiting in 24Mg+16O reaction

    International Nuclear Information System (INIS)

    The back-angle yields of the oxygen and carbon particles from the 24Mg+16O reaction have been measured at E/sub Lab/(24Mg) = 79.5 MeV by using reverse kinematics. Comparison with data for the 28Si+12C reaction forming the same compound nucleus at the same excitation energy and with very similar spin distribution, demonstrates a strong entrance channel effect which is favoring the break-up into the entrance channel with large excitation energy. This result qualitatively supports the picture of the formation of a long-lived orbiting complex whose structure and decay are dependent on the entrance channel. The compound nucleus contribution has been inferred to be less than 15% of the measured oxygen cross-section. 9 references

  9. Sodium aerosol release rate and nonvolatile fission product retention factor during a sodium-concrete reaction

    International Nuclear Information System (INIS)

    This paper reports on a series of tests conducted to study the mechanical release behavior of sodium aerosols containing nonvolatile fission products during a sodium-concrete reaction in which release behavior due to hydrodynamic breakup of the hydrogen bubble is predominant at the sodium pool surface. In the tests, nonradioactive materials, namely, strontium oxide, europium oxide, and ruthenium particles, whose sizes range from a few microns to several tens of microns, are used as nonvolatile fission product stimulants. The following results are obtained: The sodium aerosol release rate during the sodium-concrete reaction is larger than that of natural evaporation. The difference, however, becomes smaller with increasing sodium temperature: nearly ten times smaller at 400 degrees C and three times at 700 degrees C. The retention factors for the nonvolatile materials in the sodium pool increase to the range of 0.5 to 104 with an increase in the sodium temperature from 400 to 700 degrees C

  10. Experimental characterization of the spreading and break-up of liquid flat-fan sheets discharging in a low-density atmosphere and application to BrLi solutions

    Energy Technology Data Exchange (ETDEWEB)

    Palacios, E. [Universidad Politecnica de Madrid (Spain). Departamento de Mecanica Industrial; Nogueira, J.; Rodriguez, P.A.; Lecuona, A. [Universidad Carlos III de Madrid (Spain). Departamento de Ingenieria Termica y de Fluidos

    2009-02-15

    This work presents and characterizes the existence of two different regimes in the spreading and break-up of liquid flat-fan sheets when discharging in low-density atmospheres. The motivation of the study is the improvement on the absorption phenomena of lithium bromide aqueous solution when discharging in a 600-1,500 Pa water vapor environment. This corresponds to the absorber conditions in current absorption closed-cycle cooling machines. Despite this, the dimensionless characterization obtained has universal validity. The conditions that define the change in the break-up regime, the dimensionless sheet break-up length and the break-up time are given as a function of the parameters involved. Digital particle tracking velocimetry (PTV) has been applied to measure the velocity field and additional visualization techniques have been used to further characterize the break-up process. The experiments verify the existence of critical gas-to-liquid density and viscosity ratios below which gas to liquid interaction becomes negligible. The article also offers expressions that define their values as a function of the other dimensionless parameters. (orig.)

  11. Measurement of the tensor-analyzing power Ayy in deuteron breakup at 4.5 GeV/c and 80 mr

    International Nuclear Information System (INIS)

    The tensor analyzing-power Ayy in inclusive breakup of 4.5 GeV/c deuterons on berylium has been measured at /sim 80 mr of the detected proton angle. The analyzing power remains positive up to the highest measured momentum of the proton, that is in definitive contradiction with the predictions of the existing models based on the standard deuteron wave functions. The results suggest that the deuteron structure at short distances may depend on more than one independent variable. (author)

  12. Qualitative study on the breakup violence of homosexual partners%同性恋伴侣分手暴力的质性研究

    Institute of Scientific and Technical Information of China (English)

    董晓莹; 方刚

    2015-01-01

    Breakup violence between homosexual couples was refined as the violence that happened between two people ending their relationship.The study mainly collected cases from the China White Ribbon volunteer net-work for a qualitative research.This paper analyzed four aspects of homosexual breakup violence:(1 )similarities and differences between the homosexual and heterosexual partners,(2)the uniqueness of the homosexual couples’ breakup violence,(3)“forced violence”-violence mobility and (4)homosexual couples’breakup violence and gay movement.In the prevention and treatment of partner violence,the myth of only women can be victims and the abuser are all men should be got rid of firstly.Secondly,we should break the myth of binary opposition between the abuser and victim noting the mobility of the power and violence role in the intimate relationship.%同性恋伴侣分手暴力指的是同性恋情侣之间,面临结束情侣关系时,双方之间的暴力。本研究采取质性研究方法,主要从中国白丝带志愿者网络中收集案例来进行研究。文章分析了四个方面:(1)同性恋和异性恋伴侣的分手暴力的相同点与不同点。(2)同性恋伴侣分手暴力与异性恋相比所存在的独特性。(3)“被逼暴力”———暴力的流动性。(4)同性恋运动与同性伴侣分手暴力。伴侣暴力的预防与处置首先要破除受暴者都是女性,施暴者都是男性的迷思,其次是破除施暴者与受暴者二元对立的迷思,注意到权力关系与暴力关系的流动性。

  13. Pre-breakup magmatism on the Vøring Margin: Insight from new sub-basalt imaging and results from Ocean Drilling Program Hole 642E

    Science.gov (United States)

    Abdelmalak, M. M.; Meyer, R.; Planke, S.; Faleide, J. I.; Gernigon, L.; Frieling, J.; Sluijs, A.; Reichart, G.-J.; Zastrozhnov, D.; Theissen-Krah, S.; Said, A.; Myklebust, R.

    2016-04-01

    Improvements in sub-basalt imaging combined with petrological and geochemical observations from the Ocean Drilling Program (ODP) Hole 642E core provide new constraints on the initial breakup processes at the Vøring Margin. New and reprocessed high-quality seismic data allow us to identify a new seismic facies unit which we define as the Lower Series Flows. This facies unit is seismically characterized by wavy to continuous subparallel reflections with an internal disrupted and hummocky shape. Drilled lithologies, which we correlate to this facies unit, have been interpreted as subaqueous flows extruding and intruding into wet sediments. Locally, the top boundary of this facies unit is defined as a negative in polarity reflection and referred as the K-Reflection. This reflection can be correlated with the spatial extent of pyroclastic deposits, emplaced during transitional shallow marine to subaerial volcanic activities during the rift to drift transition. The drilled Lower Series Flows consist of peraluminous, cordierite bearing peperitic basaltic andesitic to dacitic flows interbedded with thick volcano-sedimentary deposits and intruded sills. The peraluminous geochemistry combined with available C (from calcite which fills vesicles and fractures), Sr, Nd, and Pb isotopes data points toward upper crustal rock-mantle magma interactions with a significant contribution of organic carbon rich pelagic sedimentary material during crustal anatexis. From biostratigraphic analyses, Apectodinium augustum was found in the Lower Series Flows. This dinoflagellate cyst species is a marker for the Paleocene - Eocene Thermal Maximum (PETM). However, based on very high stable carbon isotope ratios of bulk organic matter we exclude that these strata represent the PETM. This implies that A. augustum was reworked into the early Eocene sediments of this facies unit. Crucially, this unit predates the breakup time of the Vøring Margin. Finally, a conceptual emplacement model for the

  14. Surviving an SIS Breakup

    Science.gov (United States)

    Villano, Matt

    2010-01-01

    Divorcing one student information system and hooking up with another can cause serious upheaval. With the right plan in place, the transition to a new student information system can go surprisingly smoothly. The author interviewed technologists at Southwest Wisconsin Technical College and the Emily Griffith Opportunity School (CO) who recently…

  15. The study of 12C(α,γ astrophysical reaction using 12C(6Li,d and 12C(7Li,t reaction at 20 MeV and in the framework of the potential model

    Directory of Open Access Journals (Sweden)

    Adhikari S.

    2015-01-01

    Full Text Available The triton angular distribution in the 12C(7Li,t16O reaction has been measured at 20 MeV incident energy. Comparison of the data with Finite Range DWBA and CDCC-CRC calculations show that breakup coupling effects are prominent in the transfer to the ground state. This observation is similar to that in the 12C(6Li,d reaction at the same incident energy. The alpha spectroscopic factor of the 16O ground state is determined (Sα=0.25 from a comparison of the measured angular distribution with respect to the CDCC-CRC calculations. The E2 S-factor of the 12C(α,γ reaction at 300 keV in the framework of a potential model is determined to be about 118 keV-barn.

  16. Microfluidic chemical reaction circuits

    Science.gov (United States)

    Lee, Chung-cheng; Sui, Guodong; Elizarov, Arkadij; Kolb, Hartmuth C.; Huang, Jiang; Heath, James R.; Phelps, Michael E.; Quake, Stephen R.; Tseng, Hsian-rong; Wyatt, Paul; Daridon, Antoine

    2012-06-26

    New microfluidic devices, useful for carrying out chemical reactions, are provided. The devices are adapted for on-chip solvent exchange, chemical processes requiring multiple chemical reactions, and rapid concentration of reagents.

  17. Common Reactions After Trauma

    Science.gov (United States)

    ... here Enter ZIP code here Common Reactions After Trauma Public This section is for Veterans, General Public, Family, & Friends Common Reactions After Trauma Available in Spanish: Reacciones Comunes Después de un ...

  18. Anaphylaxis-Like Reactions

    Science.gov (United States)

    ... be "primed" by previous exposure to cause anaphylaxis, anaphylactoid reactions can occur with no previous exposure at all. ... an X-ray. Although the mechanism of an anaphylactoid reaction is different, the treatment is the same as ...

  19. Microscale Thermite Reactions.

    Science.gov (United States)

    Arnaiz, Francisco J.; Aguado, Rafael; Arnaiz, Susana

    1998-01-01

    Describes the adaptation of thermite (aluminum with metal oxides) reactions from whole-class demonstrations to student-run micro-reactions. Lists detailed directions and possible variations of the experiment. (WRM)

  20. Preequilibrium Nuclear Reactions

    International Nuclear Information System (INIS)

    After a survey on existing experimental data on precompound reactions and a description of preequilibrium reactions, theoretical models and quantum mechanical theories of preequilibrium emission are presented. The 25 papers of this meeting are analyzed separately