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1

Neutron-deuteron breakup and quasielastic scattering  

E-print Network

Quasielastic scattering and deuteron breakup in the 200 MeV region is studied by impinging a pulsed neutron beam on a deuterium target at the Weapons Neutron Research facility at the Los Alamos Neutron Science Center. The ...

Ohlson, Alice Elisabeth

2009-01-01

2

Breakup of deuterons on tritons  

SciTech Connect

The breakup reaction T (d, p)nt at the projectile deuteron energy of 36.9 MeV was studied theoretically and experimentally. The measured inclusive spectra and angular distributions of product protons are presented. A theoretical description of the reaction in question is based on the microscopic nuclear-diffractionmodel and on the theory of resonance processes. It is shown that, in T (d, p) processes, a significant role is played not only by quasifree processes involving final-state interaction that are considered in the diffraction approximation but also by the production of {sup 4}H* and {sup 4}He* resonance states. The experimental results obtained in the present study for the angular and energy distributions of final-state particles can be satisfactorily interpreted with allowance for these resonances. It is shown that only upon taking into account two {sup 4}H* resonances do the calculated spectra of protons from T (d, p) reactions appear to be in good numerical agreement with experimental data.

Beliuskina, O. O., E-mail: beliuskina@gmail.com; Grantsev, V. I.; Kisurin, K. K.; Omelchuk, S. E.; Roznyuk, Yu. S.; Rudenko, B. A.; Semenov, V. S.; Slusarenko, L. I.; Struzhko, B. G.; Tartakovsky, V. K. [National Academy of Sciences of Ukraine, Institute for Nuclear Research (Ukraine)

2012-12-15

3

Hard breakup of the deuteron into two ? isobars  

NASA Astrophysics Data System (ADS)

We study high-energy photodisintegration of the deuteron into two ? isobars at large center of mass angles within the QCD hard rescattering model (HRM). According to the HRM, the process develops in three main steps: the photon knocks a quark from one of the nucleons in the deuteron; the struck quark rescatters off a quark from the other nucleon sharing the high energy of the photon; then the energetic quarks recombine into two outgoing baryons which have large transverse momenta. Within the HRM, the cross section is expressed through the amplitude of pn??? scattering which we evaluated based on the quark-interchange model of hard hadronic scattering. Calculations show that the angular distribution and the strength of the photodisintegration is mainly determined by the properties of the pn??? scattering. We predict that the cross section of the deuteron breakup to ?++?- is 4-5 times larger than that of the breakup to the ?+?0 channel. Also, the angular distributions for these two channels are markedly different. These can be compared with the predictions based on the assumption that two hard ? isobars are the result of the disintegration of the preexisting ?? components of the deuteron wave function. In this case, one expects the angular distributions and cross sections of the breakup in both ?++?- and ?+?0 channels to be similar.

Granados, Carlos G.; Sargsian, Misak M.

2011-05-01

4

Hard breakup of the deuteron into two ? -isobars  

NASA Astrophysics Data System (ADS)

Photodisintegration of the deuteron into two ?-isobars at large center of mass angles is studied within the QCD hard rescattering model (HRM). According to the HRM, the reaction proceeds in three main steps: the photon knocks the quark from one of the nucleons in the deuteron; the struck quark rescatters off a quark from the other nucleon sharing the high energy of the photon; then the energetic quarks recombine into two outgoing baryons emerging at large transverse momenta. Within the HRM, the cross section is expressed through the amplitude of pn->?? scattering which we evaluated based on the quark-interchange model of hard hadronic scattering. We predict that the cross section of the deuteron breakup to &++circ;&-circ; is 4-5 times larger than that of the breakup to the &+circ;0? channel. Also, the angular distributions for these two channels are markedly different. These can be compared with the predictions based on the assumption that two hard ?-isobars are the result of the disintegration of initial ?? components of the deuteron wave function. In this case, the angular distributions and cross sections of the breakup in both &++circ;&-circ; and &+circ;0? channels are expected to be similar.

Granados, Carlos; Sargsian, Misak

2011-04-01

5

Three-body break-up in deuteron-deuteron scattering at 65 MeV/nucleon  

SciTech Connect

In an experiment with a 65 MeV/nucleon polarized deuteron beam on a liquid-deuterium target at Kernfysisch Versneller Instituut, several multibody final states in deuteron-deuteron scattering were identified. For these measurements, a unique and advanced detection system, called the Big Instrument for Nuclear-polarization Analysis, was utilized. We demonstrate the feasibility of measuring vector and tensor polarization observables of the deuteron break-up reaction leading to a three-body final state. The polarization observables were determined with high precision in a nearly background-free experiment. The analysis procedure and some results are presented.

Ramazani-Moghaddam-Arani, A. [Department of Physics, Faculty of Science, University of Kashan, Kashan (Iran, Islamic Republic of); KVI, University of Groningen, Groningen (Netherlands); Amir-Ahmadi, H. R.; Biegun, A.; Joulaeizadeh, L.; Kalantar-Nayestanaki, N.; Mardanpour, H.; Messchendorp, J. G.; Moeini, H.; Shende, S. V. [KVI, University of Groningen, Groningen (Netherlands); Bacher, A. D.; Bailey, C. D.; Stephenson, E. J. [Center for Exploration of Energy and Matter, Indiana University, Bloomington, Indiana (United States); Eslami-Kalantari, M. [KVI, University of Groningen, Groningen (Netherlands); Department of Physics, Faculty of Science, Yazd University, Yazd (Iran, Islamic Republic of); Gasparic, I. [Rudjer Boskovic Institute, Zagreb (Croatia); Kistryn, St.; Sworst, R. [Institute of Physics, Jagiellonian University, Cracow (Poland); Kozela, A. [Henryk Niewodniczanski, Institute of Nuclear Physics, Cracow (Poland); Micherdzinska, A. M. [University of Winnipeg, Winnipeg (Canada); Stephan, E. [Institute of Physics, University of Silesia, Katowice (Poland)

2011-02-15

6

Relativistic Effects in Neutron-Deuteron Elastic Scattering and Breakup  

NASA Astrophysics Data System (ADS)

We solved the Faddeev equation in a Poincaré invariant model of the three-nucleon system. Two-body interactions are generated so that when they are added to the two-nucleon invariant mass operator (rest energy) the two-nucleon S matrix is identical to the experimental S matrix modeled with a given nucleon-nucleon interaction. Cluster properties of the three-nucleon S-matrix determine how these two-nucleon interactions are embedded in the three-nucleon mass operator. Differences in the predictions of the relativistic and corresponding non-relativistic models for elastic and breakup processes are investigated. Of special interest are effects of relativity on the elastic scattering angular distribution and total cross sections, the lowering of the A y maximum in elastic nucleon-deuteron (Nd) scattering below ?25 MeV caused by the Wigner spin rotations and the significant changes of the breakup cross sections in certain regions of the phase-space.

Wita?a, H.; Golak, J.; Skibi?ski, R.; Glöckle, W.; Polyzou, W. N.; Kamada, H.

2011-03-01

7

Few-Nucleon System Dynamics Studied via Deuteron-Deuteron Breakup Reactions at 160 MeV  

NASA Astrophysics Data System (ADS)

An experiment, with the deuteron beams at energy of 160 MeV impinging on the liquid deuterium target, was carried out using the BINA detector at KVI, in Groningen, the Netherlands. Data were collected for the purpose of obtaining high precision differential cross-sections for the deuteron break-up reaction. The elastic scattering channel was also measured alongside for the purpose of cross-section normalization.

Khatri, G.; Ciepa?, I.; Bodek, K.; Kalantar-Nayestanaki, N.; Kistryn, St.; K?os, B.; Kozela, A.; Magiera, A.; Mazumdar, I.; Messchendorp, J.; Parol, W.; Skwira-Chalot, I.; Stephan, E.; Rozp?dzik, D.; Wro?ska, A.; Zejma, J.

2014-08-01

8

Charged-particle tracking for neutron-deuteron breakup  

E-print Network

Particle tracking software has been developed to measure the energy of protons scattered in the breakup process d(n, np)n. The nd breakup experiment is performed at the Weapons Neutron Research facilities at Los Alamos ...

Boddy, Kimberly K

2007-01-01

9

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

SciTech Connect

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.

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

10

Neutron Beams from Deuteron Breakup at the 88Inch Cyclotron at Lawrence Berkeley National Laboratory  

Microsoft Academic Search

Accelerator-based neutron sources offer many advantages, in particular tunability of the neutron beam in energy and width to match the needs of the application. Using a recently constructed neutron beam line at the 88-Inch Cyclotron at LBNL, tunable high-intensity sources of quasi-monoenergetic and broad spectrum neutrons from deuteron breakup are under development for a variety of applications.

M. A. McMahan; L. Ahle; D. L. Bleuel; L. Bernstein; B. R. Braquest; J. Cerny; L. H. Heilbronn; C. C. Jewett; I. Thompson; B. Wilson

2007-01-01

11

Neutron Beams from Deuteron Breakup at the 88-Inch Cyclotron at Lawrence Berkeley National Laboratory  

SciTech Connect

Accelerator-based neutron sources offer many advantages, in particular tunability of the neutron beam in energy and width to match the needs of the application. Using a recently constructed neutron beam line at the 88-Inch Cyclotron at LBNL, tunable high-intensity sources of quasi-monoenergetic and broad spectrum neutrons from deuteron breakup are under development for a variety of applications.

McMahan, M.A.; Ahle, L.; Bleuel, D.L.; Bernstein, L.; Braquest, B.R.; Cerny, J.; Heilbronn, L.H.; Jewett, C.C.; Thompson, I.; Wilson, B.

2007-07-31

12

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

E-print Network

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.

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

2006-01-27

13

Characterization of a Tunable Quasi-Monoenergetic Neutron Beamfrom Deuteron Breakup  

SciTech Connect

A neutron irradiation facility is being developed at the88-Inch Cyclotron at Lawrence Berkeley National Laboratory for thepurposes of measuring neutron reaction cross sections on radioactivetargets and for radiation effects testing. Applications are of benefit tostockpile stewardship, nuclear astrophysics, next generation advancedfuel reactors, and cosmic radiation biology and electronics in space. Thefacility will supply a tunable, quasi-monoenergetic neutron beam in therange of 10-30 MeV or a white neutron source, produced by deuteronbreakup reactions on thin and thick targets, respectively. Because thedeuteron breakup reaction has not been well studied at intermediateincident deuteron energies, above the target Coulomb barrier and below 56MeV, a detailed characterization was necessary of the neutron spectraproduced by thin targets.Neutron time of flight (TOF) methods have beenused to measure the neutron spectra produced on thin targets of low-Z(titanium) and high-Z (tantalum) materials at incident deuteron energiesof 20 MeV and 29 MeV at 0 deg. Breakup neutrons at both energies fromlow-Z targets appear to peak at roughly half of the available kineticenergy, while neutrons from high-Z interactions peak somewhat lower inenergy, owing to the increased proton energy due to breakup within theCoulomb field. Furthermore, neutron spectra appear narrower for high-Ztargets. These centroids are consistent with recent preliminary protonenergy measurements using silicon telescope detectors conducted at LBNL,though there is a notable discrepancy with spectral widths.

Bleuel, D.L.; McMahan, M.A.; Ahle, L.; Barquest, B.R.; Cerny, J.; Heilbronn, L.H.; Jewett, C.C.

2006-12-14

14

Deuteron breakup in the 2H(e,e'p) reaction at low momentum transfer and close to threshold  

NASA Astrophysics Data System (ADS)

Deuteron breakup is studied in an electro-induced 2H(e,e'p) coincidence experiment at low momentum transfer and close to threshold. The longitudinal-plus-transverse (L+T) and longitudinal-transverse interference (LT) structure functions are deduced. In general, calculations based on the Bonn potential and including meson exchange currents and isobar configurations describe the data well. Surprisingly large deviations are observed for angular correlations of the LT contribution.

von Neumann-Cosel, P.; Richter, A.; Schrieder, G.; Shevchenko, A.; Stiller, A.; Arenhövel, H.

2002-04-01

15

Deuteron Breakup in the 2H(e,e'p) Reaction at Low Momentum Transfer and Close to Threshold  

NASA Astrophysics Data System (ADS)

Deuteron breakup has been studied in a 2H(e,e'p) coincidence experiment at low momentum transfer and for energies close to threshold. The longitudinal-plus-transverse ( L+T) and longitudinal-transverse ( LT) interference cross sections are deduced. Nonrelativistic calculations based on the Bonn potential and including leading order relativistic contributions, meson exchange currents, and isobar configurations describe the ( L+T) data well. Surprisingly, large deviations of 30% to 45% are observed for the LT contribution.

von Neumann-Cosel, P.; Richter, A.; Schrieder, G.; Shevchenko, A.; Stiller, A.; Arenhövel, H.

2002-05-01

16

Proton--induced deuteron breakup at GeV energies with forward emission of a fast proton pair  

E-print Network

A study of the deuteron breakup reaction $pd \\to (pp)n$ with forward emission of a fast proton pair with small excitation energy $E_{pp}<$ 3 MeV has been performed at the ANKE spectrometer at COSY--J\\"ulich. An exclusive measurement was carried out at six proton--beam energies $T_p=$~0.6,~0.7,~0.8,~0.95,~1.35, and 1.9 GeV by reconstructing the momenta of the two protons. The differential cross section of the breakup reaction, averaged up to $8^{\\circ}$ over the cm polar angle of the total momentum of the $pp$ pairs, has been obtained. Since the kinematics of this process is quite similar to that of backward elastic $pd \\to dp$ scattering, the results are compared to calculations based on a theoretical model previously applied to the $pd \\to dp$ process.

V. Komarov; S. Dymov; A. Kacharava; A. Kulikov; G. Macharashvili; A. Petrus; F. Rathmann; H. Seyfarth; H. Ströher; Yu. Uzikov; S. Yaschenko; B. Zalikhanov; M. Büscher; W. Erven; M. Hartmann; A. Khoukaz; R. Koch; V. Kurbatov; N. Lang; R. Maier; S. Merzliakov; S. Mikirtytchiants; H. Müller; M. Nioradze; H. Ohm; D. Prasuhn; H. Paetz gen. Schieck; R. Schleichert; H. J. Stein; K. Watzlawik; N. Zhuravlev; K. Zwoll

2002-10-14

17

Systematic Study of Three-Nucleon Systems Dynamics in the Cross Section of the Deuteron-Proton Breakup Reaction  

NASA Astrophysics Data System (ADS)

An experiment to investigate the 1H( d, pp) n breakup reaction using a deuteron beam of 340, 380 and 400 MeV and the WASA detector has been performed at the Cooler Synchrotron COSY-Jülich. The main goal was the detailed study of various aspects of few-nucleon dynamics in the medium energy region, with particular emphasis on relativistic effects and their interplay with three nucleon forces. These effects become more important with increasing available energy in the three nucleon system. Therefore the investigations at high energies are crucial to understand their nature. The almost 4 ? geometry of the WASA detector gives an unique possibility to study various aspects of dynamics of processes in the three-nucleon reaction. Preliminary results obtained using the WASA detector are presented.

K?os, B.; Ciepa?, I.; Jamróz, B.; Khatri, G.; Kistryn, S.; Kozela, A.; Magiera, A.; Parol, W.; Skwira-Chalot, I.; Stephan, E.

2014-08-01

18

Mechanisms of the breakup of liquid jets  

Microsoft Academic Search

A general theory of the onset of breakup of liquid jets in an ambient gas is given. The theory is based on the linear stability analysis of a viscous liquid jet with respect to spatially growing disturbances. The three independent parameters in the theory are the Reynolds number R, the Weber number We, and the gas-to-liquid density ratio Q. The

S. P. Lin; Z. W. Lian

1990-01-01

19

Theory of neutron-deuteron break-up at 14.4 MeV  

Microsoft Academic Search

We report numerical calculations of proton spectra for three separable potential models of the three-body break-up reaction n+d --> n+n+p, at a neutron laboratory energy of 14.4 MeV. The first (the YY model) is that used by Aaron and Amado, but with somewhat different results. The second (the YT model) replaces the Yamaguchi form factor for the singlet nucleon-nucleon interaction

R. T. Cahill; I. H. Sloan

1971-01-01

20

Similarity between the primary and secondary air-assisted liquid jet breakup mechanism  

E-print Network

we report an ultrafast synchrotron x-ray phase contrast imaging study of the primary breakup mechanism of a coaxial air-assisted water jet. We demonstrate that there exist great similarities in the phenomenology of primary breakup with that of the secondary breakup. Especially, a membrane-mediated breakup mechanism dominates the breakup process for a wide range of air speeds. This finding reveals the intrinsic connections of these two breakup regimes and has deep implications on the unified theoretical approach in treating the breakup mechanism of high speed liquid jet.

Wang, Y J; Fezzaa, K

2007-01-01

21

Parity violation in electron-deuteron scattering. II. Break-up channels  

NASA Astrophysics Data System (ADS)

Parity violation in electron-deuteron inelastic scattering is decribed. An impulse approximation, modified to incorporate gauge invariance, is employed. Additional meson-exchange currents are included. Normal-parity and abnormal-parity wave function components are generated numerically with a Reid soft-core potential for the former and a general parity-violating weak potential with adjustable coupling constants for the latter. Numerical results for parity-conserving differential cross sections are in good agreement with existing data. For low n- p excitation energies and medium-energy electrons, we find that parity-violating asymmetries are dominated by contributions from neutral weak currents so that the Weinberg-Salam theory can be tested. For low-energy electrons, 5 MeV ? Ee ? 50 MeV, our results indicate that the asymmetry caused by nuclear parity violation is roughly as important as that due to neutral weak currents. The pion-nucleon parity-violating coupling, f?, as well as the rho- and omega-nucleon parity-violating couplings, may be determinable from such experiments. Further, it is possible to check the experiment of Lobashov et al., which detects circular polarization in the thermal-neutron capture reaction.

Hwang, W.-Y. P.; Henley, E. M.; Miller, Gerald A.

1981-12-01

22

Polarization observables in hard rescattering mechanism of deuteron photodisintegration  

NASA Astrophysics Data System (ADS)

Polarization properties of high energy photodisintegration of the deuteron are studied within the framework of the hard rescattering mechanism (HRM). In HRM, a quark of one nucleon knocked-out by the incoming photon rescatters with a quark of the other nucleon leading to the production of two nucleons with high relative momentum. Summation of all relevant quark rescattering amplitudes allows us to express the scattering amplitude of the reaction through the convolution of a hard photon-quark interaction vertex, the large angle p-n scattering amplitude and the low momentum deuteron wave function. Within HRM, it is demonstrated that the polarization observables in hard photodisintegration of the deuteron can be expressed through the five helicity amplitudes of NN scattering at high momentum transfer. At 90° CM scattering HRM predicts the dominance of the isovector channel of hard pn rescattering, and it explains the observed smallness of induced, Py and transfered, Cx polarizations without invoking the argument of helicity conservation. Namely, HRM predicts that Py and Cx are proportional to the ?5 helicity amplitude which vanishes at ?cm=90° due to symmetry reasons. HRM predicts also a nonzero value for Cz in the helicity-conserving regime and a positive ? asymmetry which is related to the dominance of the isovector channel in the hard reinteraction. We extend our calculations to the region where large polarization effects are observed in pp scattering as well as give predictions for angular dependences.

Sargsian, Misak M.

2004-05-01

23

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

SciTech Connect

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.

Benjamin J. Crowe III

2009-09-30

24

Similarity between the primary and secondary air-assisted liquid jet breakup mechanisms.  

PubMed

We report an ultrafast synchrotron x-ray phase-contrast imaging study of the primary breakup mechanism of a coaxial air-assisted water jet. There exist great similarities between the primary (jet) and the secondary (drop) breakup, and in the primary breakup on different length scales. A transition from a ligament- to a membrane-mediated breakup is identified around an effective Weber number We' approximately 13. This observation reveals the critical role an effective Weber number plays in determining the atomization process and strongly supports the cascade breakup model. PMID:18518113

Wang, Yujie; Im, Kyoung-Su; Fezzaa, Kamel

2008-04-18

25

Mechanisms and systematics of breakup in reactions of {sup 9}Be at near-barrier energies  

SciTech Connect

Below-barrier no-capture breakup measurements of the weakly bound {sup 9}Be nucleus, incident on targets ranging in atomic number from 62 to 83, have been carried out using a large-area high-resolution back-angle detector array. It is shown that the three-body reconstructed reaction Q-value and relative energy of the breakup fragments together reveal the full dynamics of the breakup mechanism, identifying all physical processes that lead to the breakup of the projectile-like nucleus. Contrasting with the simple expectation of direct breakup into the most energetically favored clusters, the data show that breakup following n-transfer dominates the total breakup yield. Breakup from long-lived states in the projectile-like nucleus, which on the reaction time scale may be considered stable, has been isolated from the prompt breakup yield. It has been shown that the prompt breakup probability essentially depends on the surface separation of the interacting nuclei. The measured prompt breakup probability functions for each target have been used together with a classical trajectory model to predict the above-barrier suppression of complete fusion. The suppression factor, expressed as the fraction of incomplete fusion, is nearly independent of target charge.

Rafiei, R.; Rietz, R. du; Luong, D. H.; Hinde, D. J.; Dasgupta, M.; Evers, M.; Diaz-Torres, A. [Department of Nuclear Physics, Research School of Physics and Engineering, Australian National University, Canberra, ACT 0200 (Australia)

2010-02-15

26

Spin structure of the "Forward" nucleon charge-exchange reaction n + p ? p + n and the deuteron charge-exchange breakup  

NASA Astrophysics Data System (ADS)

The structure of the nucleon charge-exchange process n + p ? p + n is investigated basing on the isotopic invariance of the nucleon-nucleon scattering. Using the operator of permutation of the spin projections of the neutron and proton, the connection between the spin matrices, describing the amplitude of the nucleon charge-exchange process at zero angle and the amplitude of the elastic scattering of the neutron on the proton in the "backward" direction, has been considered. Due to the optical theorem, the spin-independent part of the differential cross section of the process n + p ? p + n at zero angle for unpolarized particles is expressed through the difference of total cross sections of unpolarized proton-proton and neutron-proton scattering. Meantime, the spin-dependent part of this cross section is proportional to the differential cross section of the deuteron charge-exchange breakup d + p ? ( pp) + n at zero angle at the deuteron momentum k d = 2 k n ( k n is the initial neutron momentum). Analysis shows that, assuming the real part of the spin-independent term of the "forward" amplitude of the process n + p ? p + n to be smaller or of the same order as compared with the imaginary part, in the wide range of neutron laboratory momenta k n > 700 MeV/ c the main contribution into the differential cross section of the process n + p ? p + n at zero angle is provided namely by the spin-dependent term.

Lyuboshitz, V. L.; Lyuboshitz, V. V.

2011-02-01

27

Droplet Breakup Mechanisms in Air-blast Atomizers  

NASA Astrophysics Data System (ADS)

Atomization processes are encountered in many natural and man-made phenomena. Examples are pollen release by plants, human cough or sneeze, engine fuel injectors, spray paint and many more. The physics governing the atomization of liquids is important in understanding and utilizing atomization processes in both natural and industrial processes. We have observed the governing physics of droplet breakup in an air-blast water atomizer using a high magnification, high speed, and high resolution LASER imaging technique. The droplet breakup mechanisms are investigated in three major categories. First, the liquid drops are flattened to form an oblate ellipsoid (lenticular deformation). Subsequent deformation depends on the magnitude of the internal forces relative to external forces. The ellipsoid is converted into a torus that becomes stretched and disintegrates into smaller drops. Second, the drops become elongated to form a long cylindrical thread or ligament that break up into smaller drops (Cigar-shaped deformation). Third, local deformation on the drop surface creates bulges and protuberances that eventually detach themselves from the parent drop to form smaller drops.

Aliabadi, Amir Abbas; Taghavi, Seyed Mohammad; Lim, Kelly

2011-11-01

28

Direct processes effects on deuteron activation cross sections  

NASA Astrophysics Data System (ADS)

An extended analysis of reaction mechanisms involved in deuterons interaction with target nuclei from 27Al till 231Pa, at incident energies up to 60 MeV, is presented. Increased attention is devoted to direct processes, concerning the breakup, stripping, and pickup contributions to the deuteron activation cross sections. Finally, the pre-equilibrium and evaporation cross sections, corrected for the initial flux leakage towards direct processes, have completed the deuteron interaction analysis. The overall agreement of the measured data and model calculations proves the correctness of nuclear mechanism description.

Avrigeanu, M.; Avrigeanu, V.

2014-09-01

29

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

SciTech Connect

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 preference for the predictions in which the 3NF's are included. The majority of the experimental data points is well reproduced by the theoretical predictions. The remaining discrepancies are investigated by inspecting cross sections integrated over certain kinematical variables. The procedure of global comparisons leads to establishing regularities in disagreements between the experimental data and the theoretically predicted values of the cross sections. They indicate deficiencies still present in the assumed models of the 3N system dynamics.

St. Kistryn; E. Stephan; A. Biegun; K. Bodek; A. Deltuva; E. Epelbaum; K. Ermisch; W. Gloeckle; J. Golak; N. Kalantar-Nayestanaki; H. Kamada; M. Kis; B. Klos; A. Kozela; J. Kuros-Zolnierczuk; M. Mahjour-Shafiei; U.-G. Meissner; A. Micherdzinska; A. Nogga; P. U. Sauer; R. Skibinski; R. Sworst; H. Witala; J. Zejma; W. Zipper

2005-08-11

30

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

SciTech Connect

The breakup of a Au nucleus under bombardment with relativistic p, ..cap alpha.., and /sup 20/Ne 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.

Steinberg, E.P.

1982-01-01

31

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

NASA Technical Reports Server (NTRS)

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.

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

2012-01-01

32

Multiple mechanisms of spiral wave breakup in a model of cardiac electrical activity  

NASA Astrophysics Data System (ADS)

It has become widely accepted that the most dangerous cardiac arrhythmias are due to reentrant waves, i.e., electrical wave(s) that recirculate repeatedly throughout the tissue at a higher frequency than the waves produced by the heart's natural pacemaker (sinoatrial node). However, the complicated structure of cardiac tissue, as well as the complex ionic currents in the cell, have made it extremely difficult to pinpoint the detailed dynamics of these life-threatening reentrant arrhythmias. A simplified ionic model of the cardiac action potential (AP), which can be fitted to a wide variety of experimentally and numerically obtained mesoscopic characteristics of cardiac tissue such as AP shape and restitution of AP duration and conduction velocity, is used to explain many different mechanisms of spiral wave breakup which in principle can occur in cardiac tissue. Some, but not all, of these mechanisms have been observed before using other models; therefore, the purpose of this paper is to demonstrate them using just one framework model and to explain the different parameter regimes or physiological properties necessary for each mechanism (such as high or low excitability, corresponding to normal or ischemic tissue, spiral tip trajectory types, and tissue structures such as rotational anisotropy and periodic boundary conditions). Each mechanism is compared with data from other ionic models or experiments to illustrate that they are not model-specific phenomena. Movies showing all the breakup mechanisms are available at http://arrhythmia.hofstra.edu/breakup and at ftp://ftp.aip.org/epaps/chaos/E-CHAOEH-12-039203/ INDEX.html. The fact that many different breakup mechanisms exist has important implications for antiarrhythmic drug design and for comparisons of fibrillation experiments using different species, electromechanical uncoupling drugs, and initiation protocols.

Fenton, Flavio H.; Cherry, Elizabeth M.; Hastings, Harold M.; Evans, Steven J.

2002-09-01

33

Measurement of tensor polarization of deuterons from 3He?d+p breakup at momenta from 4.60 to 5.66 GeV/c  

NASA Astrophysics Data System (ADS)

The tensor polarization ?20 of deuterons emitted in the 1H(3He,d?)X reaction at 0? in the laboratory system was measured at the Saturne National Laboratory in Saclay using the SPES-4 spectrometer with the HYPOM polarimeter located downstream from its focal plane. The momentum of the detected deuterons was kept fixed at 3.77 GeV/c, while the momentum of the 3He beam was varied from 4.60 to 5.66 GeV/c, thus providing a range of internal momenta k of the deuteron in 3He from 0 up to 0.4 GeV/c. The data obtained are compared with theoretical predictions.

Sitnik, I. M.; Perdrisat, C. F.; Tomasi-Gustafsson, E.; Ball, J.; Bimbot, L.; Bisson, Y.; Boivin, M.; Borzunov, Yu. T.; Boyard, J. L.; Courtat, Ph.; Gacougnolle, R.; Golovanov, L. B.; Hennino, T.; Jones, M. K.; Kunne, R.; Malinina, L. V.; Nedev, S.; Piskunov, N. M.; Punjabi, V.; Sans, J. L.; Skowron, R.; Strokovsky, E. A.; Yonnet, J.

2011-09-01

34

Measurement of tensor polarization of deuterons from 3He ? d + p breakup at internal momenta up to 0.4 GeV/c  

NASA Astrophysics Data System (ADS)

The tensor polarization (?20) of deuterons emitted in the p(3He,d)X reaction at 0° in the lab. system was measured at the Saturne National Laboratory in Saclay, using the SPES-4 spectrometer with the HYPOM polarimeter in the area of its focal plane. The momentum of the detected deuterons was kept fixed at 3.77 GeV/c, while the momentum of the 3He beam was varied from 4.60 to 5.66 GeV/c, thus providing a range of internal momenta k of the deuteron inside the 3He from 0 up to 0.4 GeV/c. The obtained data are compared with the theoretical predictions.

Sitnik, I. M.; Perdrisat, C. F.; Tomasi-Gustafsson, E.; Ball, J.; Bimbot, L.; Bisson, Y.; Boivin, M.; Borzunov, Yu T.; Boyard, J. L.; Courtat, Ph; Gacougnolle, R.; Garçon, M.; Golovanov, L. B.; Hennino, T.; Jones, M. K.; Kunne, R.; Malinina, L. V.; Nedev, S.; Piskunov, N. M.; Punjabi, V.; Sans, J. L.; Skowron, R.; Strokovsky, E. A.; Yonnet, J.

2011-05-01

35

Interplay between valence and core excitation mechanisms in the breakup of halo nuclei.  

PubMed

The phenomenon of core excitation in the breakup of a two-body halo nucleus is investigated. We show that this effect plays a significant role in the reaction dynamics and, furthermore, its interference with the valence excitation mechanism has sizable and measurable effects on the breakup angular distributions. These effects have been studied in the resonant breakup of (11)Be on a carbon target, populating the resonances at 1.78 MeV (5/2(+)) and 3.41 MeV (3/2(+)). The calculations have been performed using a recent extension of the distorted-wave Born approximation method, which takes into account the effect of core excitation in both the structure of the halo nucleus and in the reaction mechanism. The calculated angular distributions have been compared with the available data [Fukuda et al., Phys. Rev. C 70, 054606 (2004).]. Although each of these resonances is dominated by one of the two considered mechanisms, the angular patterns of these resonances depend in a very delicate way on the interference between them. This is the first clear evidence of this effect but the phenomenon is likely to occur in other similar reactions. PMID:23368187

Moro, A M; Lay, J A

2012-12-01

36

Measurement of tensor polarization of deuterons from {sup 3}He{yields}d+p breakup at momenta from 4.60 to 5.66 GeV/c  

SciTech Connect

The tensor polarization {rho}{sub 20} of deuterons emitted in the {sup 1}H({sup 3}He,d)X reaction at 0 deg. in the laboratory system was measured at the Saturne National Laboratory in Saclay using the SPES-4 spectrometer with the HYPOM polarimeter located downstream from its focal plane. The momentum of the detected deuterons was kept fixed at 3.77 GeV/c, while the momentum of the {sup 3}He beam was varied from 4.60 to 5.66 GeV/c, thus providing a range of internal momenta k of the deuteron in {sup 3}He from 0 up to 0.4 GeV/c. The data obtained are compared with theoretical predictions.

Sitnik, I. M.; Borzunov, Yu. T.; Golovanov, L. B.; Malinina, L. V.; Piskunov, N. M.; Strokovsky, E. A. [Joint Institute for Nuclear Research, RU-141980 Dubna (Russian Federation); Perdrisat, C. F. [College of William and Mary, Williamsburg, Virgina 23187 (United States); Tomasi-Gustafsson, E.; Ball, J. [CEA/DSM CNRS/IN2P3 Laboratoire National Saturne, CE Saclay (France); DAPNIA/SPhN CEA/Saclay, F-91191 Gif-sur-Yvette Cedex (France); Bimbot, L.; Bisson, Y.; Boyard, J. L.; Courtat, Ph.; Gacougnolle, R.; Hennino, T.; Kunne, R.; Skowron, R. [CNRS/IN2P3 IPN, F-91400 Orsay (France); Boivin, M.; Sans, J. L.; Yonnet, J. [CEA/DSM CNRS/IN2P3 Laboratoire National Saturne, CE Saclay (France)

2011-09-15

37

Emplacement mechanisms for Continental Flood Basalts and implications for plume activity during incipient continental breakup  

Microsoft Academic Search

We use model experiments to address the dynamics of magma upwelling during incipient break up of the continental lithosphere. In particular we study the emplacement mechanisms responsible for formation of Continental Flood Basalts. The models show that the dynamics of melt upwelling and distribution and the surface topography are all sensitive to the boundary conditions and the rheological stratification. When

Genene Mulugeta; Bekele Abebe; Tesfaye Korme; Dimitrios Sokoutis

2007-01-01

38

Delta-Isobar Production in the Hard Photodisintegration of a Deuteron  

NASA Astrophysics Data System (ADS)

Hard photodisintegration of the deuteron in delta-isobar production channels is proposed as a useful process in identifying the quark structure of hadrons and of hadronic interactions at large momentum and energy transfer. The reactions are modeled using the hard re scattering model, HRM, following previous works on hard breakup of a nucleon nucleon (NN) system in light nuclei. Here,quantitative predictions through the HRM require the numerical input of fits of experimental NN hard elastic scattering cross sections. Because of the lack of data in hard NN scattering into ?-isobar channels, the cross section of the corresponding photodisintegration processes cannot be predicted in the same way. Instead, the corresponding NN scattering process is modeled through the quark interchange mechanism, QIM, leaving an unknown normalization parameter. The observables of interest are ratios of differential cross sections of ?-isobar production channels to NN breakup in deuteron photodisintegration. Both entries in these ratios are derived through the HRM and QIM so that normalization parameters cancel out and numerical predictions can be obtained. )

Granados, Carlos; Sargsian, Misak

2010-02-01

39

Electrostatic Breakup in a Misty Plasma  

SciTech Connect

A misty plasma is defined as a plasma containing small liquid droplets. In such a system, the droplets will undergo total electrostatic breakup if their charge exceeds the well-known Rayleigh limit. This imposes a minimum size on the droplets. Electrostatic breakup is a significant mechanism limiting droplet survival in a wide range of plasma applications, including plasma-enhanced chemical vapor deposition and fusion tokamaks.

Coppins, M. [Blackett Laboratory, Imperial College London, London SW7 2BZ (United Kingdom)

2010-02-12

40

Relativistic Effects in Neutron–Deuteron Elastic Scattering and Breakup  

Microsoft Academic Search

We solved the Faddeev equation in a Poincaré invariant model of the three-nucleon system. Two-body interactions are generated\\u000a so that when they are added to the two-nucleon invariant mass operator (rest energy) the two-nucleon S matrix is identical to the experimental S matrix modeled with a given nucleon–nucleon interaction. Cluster properties of the three-nucleon S-matrix determine how these\\u000a two-nucleon interactions

H. Witala; J. Golak; R. Skibinski; W. Glöckle; W. N. Polyzou; H. Kamada

2011-01-01

41

Neutron Halo and Breakup Reactions  

NASA Astrophysics Data System (ADS)

Characteristic features of neutron halos in the context of breakup experiments at intermediate/high energies are discussed. Neutron halos have been found for light neutron rich nuclei along the neutron drip line, as intense radioactive nuclear beams have become available in recent years. A neutron halo nucleus is composed of a tightly bound core surrounded by one or two neutrons which extend outside of the mean field potential due to quantum tunneling. Coulomb breakup of halo nuclei shows extremely enhanced cross sections for such systems, originating from the characteristic electric dipole response of halo nuclei at low excitation energies, called soft E1 excitation. Such features are shown for one-neutron halo nuclei by Coulomb breakup experiments of {}^{11}Be on Pb at about 70 MeV/nucleon, performed at RIKEN, where it was found that the direct breakup mechanism is responsible for this excitation. We then show how the E1 excitation spectrum can be related to properties of the halo distribution, and hence that the method of Coulomb breakup is a powerful spectroscopic tool. As such, applications of the Coulomb breakup of {}^{15}C and {}^{19}C are shown. The {}^{19}C case is valuable for extracting the microscopic structure of {}^{19}C, which has only recently been clarified. The {}^{15}C case can be used to extract the radiative capture cross section of the {}^{14}C(n,?)^{15}C reaction. We then demonstrate recent applications of the "inclusive" Coulomb breakup method to a new-region of loosely bound nuclei near the island of inversion (N˜20). There, evidence obtained, of the 1n halo structure in {}^{31}Ne, is presented. In the 2n halo case the Coulomb breakup of {}^{11}Li at 70 MeV/nucleon, measured at RIKEN, is shown. This reaction has provided evidence of dineutron-like structure, revealed by the strong enhancement of the soft E1 excitation. For nuclear dominated breakup, where a light target is used, the momentum distribution of the core fragment has key information on the halo distribution, and the single-particle properties of the valence neutron. Here we show an example of a spectroscopic study of {}^{13}Be, populated by removing one neutron from the two neutron halo nucleus {}^{14}Be. These results show that the breakup reactions play significant roles in elucidating the structures along the neutron drip line. This feature will be very important for further investigations of the drip-line nuclei towards the heavier region, as will be produced using the new-generation RI (Rare-Isotope) beam facilities, as has just been completed in RIKEN (RIBF) in Japan. Such enhanced RI-beam facilities are soon to be commissioned in Europe (SPIRAL2, FAIR etc.), in Asia (KoRIA), and in the US (FRIB).

Nakamura, T.; Kondo, Y.

42

Mechanisms of the ZINC(64)(DEUTERON, LITHIUM-6)-SODIUM-60 Reaction at E(lab) = 16.4 Mev  

NASA Astrophysics Data System (ADS)

Cross-sections, A_{y}, A_{yy} , and A_{xx} for the ^{64}Zn(d, ^6Li) reaction forming the ground and first excited states of ^{60}Ni were measured in 5^circ steps from theta_{lab} = 25^circ to 80 ^circ using an E_{lab} = 16.4 MeV beam of vector and tensor polarized deuterons. These data include the first measurement of A_{xx} and A_{yy} for the (d,^6Li) reaction on a medium to heavy target nucleus. The A_{y} measurement is also among the first for (d,^6Li) reactions. Also measured were excitation functions of dsigma/d Omega for the (d,^6 Li) reactions on ^{36} Ar, ^{40}Ca, and ^{64}Zn and angular distributions of dsigma/dOmega for ^{60}Ni(^6 Li,^6Li) scattering at E _{lab} = 14.8 MeV and of dsigma/dOmega , A_{y}, A_{yy}, and A _{xx} for ^{64}Zn(d,d) scattering at E _{lab} = 16.4 MeV. The ^6Li ground state and seven other wave functions, each representing ^6Li continuum states of a given spin, I, and internal orbital angular momentum, l, l <=q 2, were included in coupled-channels (CC) calculations of ^ {60}Ni(^6Li, ^6Li) elastic scattering and finite-range, coupled-channel Born approximation (CCBA) calculations for the ^{64}Zn(d, ^6Li) reaction forming the ^ {60}Ni ground state. This analysis is the first to consider the influence of ^6 Li continuum states on the (d,^6 Li) reaction. The ^6Li- ^{60}Ni interactions were generated using a cluster folding model. Both the folding model and the CC and CCBA calculations were performed by the code FRESCO. (Tho88). For the ^{64}Zn(d, ^6Li) reaction, CCBA calculations demonstrated that alpha transfers forming the 3^+ state of ^6Li affect dsigma/d Omega and A_{ y} very strongly. However, the calculations predicted predominantly positive values of A_ {y}, whereas the measured values of A_{y} are predominantly negative. To a lesser degree, transfers forming the other ^6Li continuum states also influenced the predicted (d,^6 Li) cross-sections and analyzing powers.

Bowsher, James Edwin

43

Elasto-capillary thinning and breakup of model elastic liquids  

E-print Network

and breakup of polymeric liquid jets. Newtonian jets rapidly neck down under capillary action and pinch offElasto-capillary thinning and breakup of model elastic liquids Shelley L. Anna DivisionKinleya) Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139

44

Two facets of the deuteron  

SciTech Connect

Two of the simplest nuclear reactions, electron deuteron elastic scattering and deuteron photodisintegration, will be discussed. In particular, measurements of the tensor analyzing power T{sub 20} in e-d scattering performed with a polarized gas target in the VEPP-3 electron storage ring will be presented. In addition, measurements of deuteron photodisintegration at high energy performed at SLAC will be discussed. The meson-exchange calculations appear to agree well with al available data for electron-deuteron elastic scattering, while the constituent counting rules appear to describe the high-energy deuteron photodisintegration results at {theta}cm = 90{degrees}.

Holt, R.J.

1992-01-01

45

An experimental investigation into liquid jetting modes and break-up mechanisms conducted in a new reduced gravity facility  

Microsoft Academic Search

Liquid jets, important to many industrial applications including various drop-on-demand processes, are experimentally produced\\u000a in reduced gravity conditions and analysed to determine the mode the liquid jet is operating in. Three physically different\\u000a modes of liquid jetting are observed along with their associated break up mechanisms and discussed. Additionally, a) the theoretical\\u000a transition between jetting and the onset of chaotic

Barnaby P. Osborne; Theodore A. Steinberg

2006-01-01

46

Dynamic NMR study of the mechanisms of double, triple, and quadruple proton and deuteron transfer in cyclic hydrogen bonded solids of pyrazole derivatives.  

PubMed

Using dynamic solid state (15)N CPMAS NMR spectroscopy (CP = cross polarization, MAS = magic angle spinning), the kinetics of the degenerate intermolecular double and quadruple proton and deuteron transfers in the cyclic dimer of (15)N labeled polycrystalline 3,5-diphenyl-4-bromopyrazole (DPBrP) and in the cyclic tetramer of (15)N labeled polycrystalline 3,5-diphenylpyrazole (DPP) have been studied in a wide temperature range at different deuterium fractions in the mobile proton sites. Rate constants were measured on a millisecond time scale by line shape analysis of the doubly (15)N labeled compounds, and by magnetization transfer experiments on a second timescale of the singly (15)N labeled compounds in order to minimize the effects of proton-driven (15)N spin diffusion. For DPBrP the multiple kinetic HH/HD/DD isotope effects could be directly obtained. By contrast, four rate constants k(1) to k(4) were obtained for DPP at different deuterium fractions. Whereas k(1) corresponds to the rate constant k(HHHH) of the HHHH isotopolog, an appropriate kinetic reaction model was needed for the kinetic assignment of the other rate constants. Using the model described by Limbach, H. H.; Klein, O.; Lopez Del Amo, J. M.; Elguero, J. Z. Phys. Chem. 2004,218, 17, a concerted quadruple proton-transfer mechanism as well as a stepwise consecutive single transfer mechanism could be excluded. By contrast, using the kinetic assignment k(2) approximately k(3) approximately k(HHHD) approximately k(HDHD) and k(3) approximately k(HDDD) approximately k(DDDD), the results could be explained in terms of a two-step process involving a zwitterionic intermediate. In this mechanism, each reaction step involves the concerted transfer of two hydrons, giving rise to primary kinetic HH/HD/DD isotope effects, whereas the nontransferred hydrons only contribute small secondary effects, which are not resolved experimentally. By contrast, the multiple kinetic isotope effects of the double proton transfer in DPBrP and of the triple proton proton transfer in cyclic pyrazole trimers studied previously indicate concerted transfer processes. Thus, between n = 3 and 4 a switch of the reaction mechanism takes place. This switch is rationalized in terms of hydrogen bond compression effects associated with the multiple proton transfers. The Arrhenius curves of all processes are nonlinear and indicate tunneling processes at low temperatures. In a preliminary analysis, they are modeled in terms of the Bell-Limbach tunneling model. PMID:15366920

Klein, Oliver; Aguilar-Parrilla, Francisco; Lopez, Juan Miguel; Jagerovic, Nadine; Elguero, José; Limbach, Hans-Heinrich

2004-09-22

47

Excitation of the Delta(1232) isobar in deuteron charge exchange on hydrogen at 1.6, 1.8, and 2.3 GeV  

E-print Network

The charge-exchange break-up of polarised deuterons pol{d}p -> {pp}n, where the final {pp} diproton system has a very low excitation energy and hence is mainly in the 1S0 state, is a powerful tool to probe the spin-flip terms in the proton-neutron charge-exchange scattering. Recent measurements with the ANKE spectrometer at the COSY storage ring at 1.6, 1.8, and 2.27 GeV have extended these studies into the pion-production regime in order to investigate the mechanism for the excitation of the Delta(1232) isobar in the pol{d}p -> {pp}X reaction. Values of the differential cross section and two deuteron tensor analysing powers, A_{xx} and A_{yy}, have been extracted in terms of the momentum transfer to the diproton or the invariant mass Mx of the unobserved system X. The unpolarised cross section in the high Mx region is well described in a model that includes only direct excitation of the Delta isobar through undistorted one pion exchange. However, the cross section is grossly underestimated for low Mx, even when Delta excitation in the projectile deuteron is included in the calculation. Furthermore, direct Delta production through one pion exchange only reproduces the angular dependence of the difference between the two tensor analysing powers.

D. Mchedlishvili; S. Barsov; J. Carbonell; D. Chiladze; S. Dymov; A. Dzyuba; R. Engels; R. Gebel; V. Glagolev; K. Grigoryev; P. Goslawski; M. Hartmann; O. Imambekov; A. Kacharava; V. Kamerdzhiev; I. Keshelashvili; A. Khoukaz; V. Komarov; P. Kulessa; A. Kulikov; A. Lehrach; N. Lomidze; B. Lorentz; G. Macharashvili; R. Maier; S. Merzliakov; M. Mielke; M. Mikirtychyants; S. Mikirtychyants; M. Nioradze; H. Ohm; M. Papenbrock; D. Prasuhn; F. Rathmann; V. Serdyuk; H. Seyfarth; H. J. Stein; E. Steffens; H. Stockhorst; H. Ströher; M. Tabidze; S. Trusov; Yu. Uzikov; Yu. Valdau; C. Wilkin

2013-05-23

48

Excitation of the ?(1232) isobar in deuteron charge exchange on hydrogen at 1.6, 1.8, and 2.3 GeV  

NASA Astrophysics Data System (ADS)

The charge-exchange break-up of polarised deuterons d?p?{pp}sn, where the final {pp}s diproton system has a very low excitation energy and hence is mainly in the S01 state, is a powerful tool to probe the spin-flip terms in the proton-neutron charge-exchange scattering. Recent measurements with the ANKE spectrometer at the COSY storage ring at 1.6, 1.8, and 2.27 GeV have extended these studies into the pion-production regime in order to investigate the mechanism for the excitation of the ?(1232) isobar in the d?p?{pp}sX reaction. Values of the differential cross section and two deuteron tensor analysing powers, Axx and Ayy, have been extracted as functions of the momentum transfer to the diproton or the invariant mass MX of the unobserved system X. The unpolarised cross section in the high MX region is well described in a model that includes only direct excitation of the ? isobar through undistorted one pion exchange. However, the cross section is grossly underestimated for low MX, even when ? excitation in the projectile deuteron is included in the calculation. Furthermore, direct ? production through one pion exchange only reproduces the angular dependence of the difference between the two tensor analysing powers.

Mchedlishvili, D.; Barsov, S.; Carbonell, J.; Chiladze, D.; Dymov, S.; Dzyuba, A.; Engels, R.; Gebel, R.; Glagolev, V.; Grigoryev, K.; Goslawski, P.; Hartmann, M.; Imambekov, O.; Kacharava, A.; Kamerdzhiev, V.; Keshelashvili, I.; Khoukaz, A.; Komarov, V.; Kulessa, P.; Kulikov, A.; Lehrach, A.; Lomidze, N.; Lorentz, B.; Macharashvili, G.; Maier, R.; Merzliakov, S.; Mielke, M.; Mikirtychyants, M.; Mikirtychyants, S.; Nioradze, M.; Ohm, H.; Papenbrock, M.; Prasuhn, D.; Rathmann, F.; Serdyuk, V.; Seyfarth, H.; Stein, H. J.; Steffens, E.; Stockhorst, H.; Ströher, H.; Tabidze, M.; Trusov, S.; Uzikov, Yu.; Valdau, Yu.; Wilkin, C.

2013-10-01

49

Large Q{sup 2} electrodisintegration of the deuteron in the virtual nucleon approximation  

SciTech Connect

The two-body breakup of the deuteron is studied at high-Q{sup 2} kinematics, with the main motivation to probe the deuteron at small internucleon distances. Such studies are associated with the probing of the high-momentum component of the deuteron wave function. For this, two main theoretical issues have been addressed: electromagnetic interaction of the virtual photon with the bound nucleon and the strong interaction of produced baryons in the final state of the breakup reaction. Within virtual nucleon approximation we developed a new prescription to account for the bound nucleon effects in electromagnetic interaction. The final-state interaction at high-Q{sup 2} kinematics is calculated within the generalized eikonal approximation (GEA). We studied the uncertainties involved in the calculation and performed comparisons with the first experimental data on deuteron electrodisintegration at large Q{sup 2}. We demonstrate that the experimental data confirm the GEA's early prediction that the rescattering is maximal at approx70 deg. of recoil nucleon production relative to the momentum of the virtual photon. Comparisons also show that the forward recoil nucleon angles are best suited for studies of the electromagnetic interaction of bound nucleons and the high-momentum structure of the deuteron. Backward recoil angle kinematics show sizable effects owing to the DELTA-isobar contribution. The latter indicates the importance of further development of the GEA to account for the inelastic transitions in the intermediate state of the electrodisintegration reactions.

Sargsian, Misak M. [Florida International University, Miami, Florida 33199 (United States)

2010-07-15

50

Neutron-Deuteron Scattering Observables at E lab = 14.1 MeV  

NASA Astrophysics Data System (ADS)

Inelastic neutron-deuteron scattering is studied on the basis of configuration-space Faddeev equations. Calculated are neutron-deuteron breakup amplitudes using AV14 nucleon-nucleon potential at incident neutron energy of 14.1 MeV. The results of calculations are presented for the differential cross sections under quasi free scattering and space-star configurations, and compared with those of the previous calculations and experimental data. The choice of the cutoff radius R cutoff for asymptotic conditions is discussed.

Suslov, V. M.; Braun, M. A.; Filikhin, I.; Slaus, I.; Vlahovic, B.

2014-08-01

51

GEANT4 simulation of dp non-mesonic breakup reaction at 300 and 500 MeV  

NASA Astrophysics Data System (ADS)

GEANT4 simulations of the reaction dp ? ppn, i.e. the dp non-mesonic breakup reaction, at 300 and 500 MeV of deuteron energy for different detector configurations are presented. Two threads made from polyethylene and carbon with the thickness of 10 ?m are used as targets. The goal of the simulations is to find a method by means of which the signal from the dp non-mesonic breakup can be separated from the background that mainly comes from the carbon content of the CH2 target. The obtained results will be used in the experimental spin program that will be realized in Nuclotron in Dubna. The aim of this experimental investigation is to contribute to the elucidation of the structure of the spin dependent parts of the nucleon-nucleon and three-nucleon forces acting in the dp non-mesonic breakup. The deuteron energies will be ranging from 300 up to 500 MeV.

Janek, M.; Trpišová, B.; Piyadin, S. M.; Ladygin, V. P.

2014-07-01

52

Low-energy neutron-deuteron reactions with N3LO chiral forces  

E-print Network

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.

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

53

Low-energy neutron-deuteron reactions with N3LO chiral forces  

E-print Network

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.

J. Golak; R. Skibinski; K. Topolnicki; H. Witala; E. Epelbaum; H. Krebs; H. Kamada; Ulf-G. Meißner; V. Bernard; P. Maris; J. Vary; S. Binder; A. Calci; K. Hebeler; J. Langhammer; R. Roth; A. Nogga; S. Liebig; D. Minossi

2014-10-03

54

Transient liquid jet breakup model and comparison with phase doppler measurements  

Microsoft Academic Search

A new liquid jet breakup model is developed based on the transient breakup mechanism and incorporated into the KIVA-II code.\\u000a Liquid column is considered as a chain of balls. Rayleigh-Taylor instability and Kelvin-Helmholtz instability was applied\\u000a to the liquid jet column. Liquid jet column is continuously surveyed to apply breakup mechanisms. Once liquid droplets are\\u000a separated from the main liquid

Sang Ku Chang; Ja Ye Koo; Hong Chul Chung

1995-01-01

55

Differential and total cross sections of noncapture breakup reactions in the 6Li+144Sm system  

NASA Astrophysics Data System (ADS)

The breakup of the projectile-like fragments in reactions induced by 6Li beams on a 144Sm target at energies close to the Coulomb barrier has been measured through the coincident detection of the emitted light particles. The emphasis of the measurements and the data analysis were placed in the complete characterization of the ?-deuteron breakup mode by means of the identification of the breakup fragments and the determination of the total Q value, relative energy of the breakup products, and the angular distribution of their emission. Within the ranges of these variables covered by the present measurements, the results for the 6Li?d+? mode show a clear dominance of the resonant channel through the 3+ state at 2.186 MeV over other resonant and nonresonant channels. Differential cross sections as a function of the center-of-mass angles of the intermediate binary collision and of the breakup emission, as well as integrated cross sections as a function of energy, have been obtained. The data are compared with those measured for competing processes in the same system and with the results of calculations based on a dynamic classical model that describes noncapture breakup, incomplete fusion, and complete fusion.

Martinez Heimann, D.; Pacheco, A. J.; Capurro, O. A.; Arazi, A.; Balpardo, C.; Cardona, M. A.; Carnelli, P. F. F.; de Barbará, E.; Fernández Niello, J. O.; Figueira, J. M.; Hojman, D.; Martí, G. V.; Negri, A. E.; Rodrígues, D.

2014-01-01

56

Secondary breakup of coal water slurry drops  

NASA Astrophysics Data System (ADS)

To investigate secondary atomization of coal water slurry (CWS), deformation and breakup of eight kinds of CWS drops are presented using high speed digital camera. Based on morphology, deformation and breakup regimes of CWS drops can be termed some different modes: deformation, multimode breakup (including two sub-modes: hole breakup and tensile breakup), and shear breakup. Correlations on the ranges of breakup modes are also obtained. The conventional Weber number and Ohnesorge number are found to be insufficient to classify all breakup modes of CWS drops, so two other non-dimensional numbers based on rheology of CWS are suggested to use in the deformation and breakup regime map. Finally, total breakup time is studied and correlated, which increases with Ohnesorge number.

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

2011-11-01

57

Excitation of the Delta(1232) isobar in deuteron charge exchange on hydrogen at 1.6, 1.8, and 2.3 GeV  

E-print Network

The charge-exchange break-up of polarised deuterons pol{d}p -> {pp}n, where the final {pp} diproton system has a very low excitation energy and hence is mainly in the 1S0 state, is a powerful tool to probe the spin-flip terms in the proton-neutron charge-exchange scattering. Recent measurements with the ANKE spectrometer at the COSY storage ring at 1.6, 1.8, and 2.27 GeV have extended these studies into the pion-production regime in order to investigate the mechanism for the excitation of the Delta(1232) isobar in the pol{d}p -> {pp}X reaction. Values of the differential cross section and two deuteron tensor analysing powers, A_{xx} and A_{yy}, have been extracted in terms of the momentum transfer to the diproton or the invariant mass Mx of the unobserved system X. The unpolarised cross section in the high Mx region is well described in a model that includes only direct excitation of the Delta isobar through undistorted one pion exchange. However, the cross section is grossly underestimated for low Mx, even w...

Mchedlishvili, D; Carbonell, J; Chiladze, D; Dymov, S; Dzyuba, A; Engels, R; Gebel, R; Glagolev, V; Grigoryev, K; Goslawski, P; Hartmann, M; Imambekov, O; Kacharava, A; Kamerdzhiev, V; Keshelashvili, I; Khoukaz, A; Komarov, V; Kulessa, P; Kulikov, A; Lehrach, A; Lomidze, N; Lorentz, B; Macharashvili, G; Maier, R; Merzliakov, S; Mielke, M; Mikirtychyants, M; Mikirtychyants, S; Nioradze, M; Ohm, H; Papenbrock, M; Prasuhn, D; Rathmann, F; Serdyuk, V; Seyfarth, H; Stein, H J; Steffens, E; Stockhorst, H; Ströher, H; Tabidze, M; Trusov, S; Uzikov, Yu; Valdau, Yu; Wilkin, C

2013-01-01

58

Observation of a breakup-induced ?-transfer process for some bound states of O16 populated by the C12(Li6,d)O16* reaction  

NASA Astrophysics Data System (ADS)

Background: The 12C(6Li,d) reaction has been used as an indirect method to calculate the astrophysical S factor for the C12(? ,?) reaction at Gamow energy (300 keV). Purpose: The 12C(6Li,d) reaction is usually interpreted in terms of direct transfer. In this work we investigate the reaction mechanism and determine the effects of breakup on transfer and therefore on the extracted spectroscopic amplitudes. Method: The deuteron angular distributions for the 12C(6Li,d)16O*has been measured at 20 MeV, populating discrete states of O16. continuum discretized coupled channel-coupled reaction channel (CDCC-CRC) calculations have been used to analyze the data. Results: Results show a new reaction mechanism, where transfer occurs after the breakup of the loosely bound Li6 in the population of some bound states of O16. A comparison of the CDCC-CRC calculations with respect to the measured data were used to determine the ? spectroscopic amplitudes and factors for the different states of O16. Using the spectroscopic amplitudes obtained in this work, the E2 S factor for the C12(?,?) reaction has been calculated in the framework of a two-body potential model and compared to measurements. Conclusions: The present study very clearly shows that the breakup and transfer coupling effects are strong in the 12C(6Li ,d) reaction. The present work extracts, in the framework of a coupled reaction channel theory, the spectroscopic amplitudes of the bound and unbound states of O16. All previous analysis and new measurements should therefore be reexamined from this viewpoint to extract the astrophysical observables correctly.

Adhikari, S.; Basu, C.; Thompson, I. J.; Sugathan, P.; Jhinghan, A.; Golda, K. S.; Babu, A.; Singh, D.; Ray, S.; Mitra, A. K.

2014-04-01

59

Phenomenology of the Deuteron Electromagnetic Form Factors  

E-print Network

A rigorous extraction of the deuteron charge form factors from tensor polarization data in elastic electron-deuteron scattering, at given values of the 4-momentum transfer, is presented. Then the world data for elastic electron-deuteron scattering is used to parameterize, in three different ways, the three electromagnetic form factors of the deuteron in the 4-momentum transfer range 0-7 fm^-1. This procedure is made possible with the advent of recent polarization measurements. The parameterizations allow a phenomenological characterization of the deuteron electromagnetic structure. They can be used to remove ambiguities in the form factors extraction from future polarization data.

TheJLAB t20 collaboration; D. Abbott

2000-02-04

60

Phenomenology of the deuteron electromagnetic form factors  

SciTech Connect

A rigorous extraction of the deuteron charge form factors from tensor polarization data in elastic electron-deuteron scattering, at given values of the 4-momentum transfer, is presented. Then the world data for elastic electron-deuteron scattering is used to parameterize, in three different ways, the three electromagnetic form factors of the deuteron in the 4-momentum transfer range 0-7 fm. This procedure is made possible with the advent of recent polarization measurements. The parameterizations allow a phenomenological characterization of the deuteron electromagnetic structure. They can be used to remove ambiguities in the form factors extraction from future polarization data.

David Abbott; Abdellah Ahmidouch; H. Anklin; J. Arvieux; James P. Ball; Shelton Beedoe; Elizabeth Beise; Louis Bimbot; Werner Boeglin; Herbert Breuer; Roger Carlini; Nicholas Chant; Samuel Danagoulian; K. Dow; Jean-Eric Ducret; Jim Dunne; Lars Ewell; L. Eyraud; C. Furget; Michel Garcon; Ron Gilman; Charles Glashausser; Paul Gueye; Kenneth Gustafsson; Kawtar Hafidi; A. Honegger; J. Jourdan; Serge Kox; Gerfried Kumbartzki; L. Lu; Allison Lung; Pete Markowitz; Justin McIntyre; David Meekins; F. Merchez; Joseph Mitchell; R. Mohring; S. Mtingwa; H. Mrktchyan; D. Pitz; Liming Qin; Ronald Ransome; J.-S. R'eal; Philip Roos; Paul Rutt; Reyad Sawafta; Stepan Stepanyan; Raphael Tieulent; E. Tomasi-Gustafsson; William Turchinetz; K. Vansyoc; J. Volmer; E. Voutier; Claude Williamson; Stephen Wood; Chen Yan; Jianguo Zhao; W. Zhao

2000-04-01

61

Phenomenology of the deuteron electromagnetic form factors  

SciTech Connect

A rigorous extraction of the deuteron charge form factors from tensor polarization data in elastic electron-deuteron scattering, at given values of the 4-momentum transfer, is presented. Then the world data for elastic electron-deuteron scattering is used to parameterize, in three different ways, the three electromagnetic form factors of the deuteron in the 4-momentum transfer range 0-7 fm. This procedure is made possible with the advent of recent polarization measurements. The parameterizations allow a phenomenological characterization of the deuteron electromagnetic structure. They can be used to remove ambiguities in the form factors extraction from future polarization data.

David Abbott; Abdellah Ahmidouch; H. Anklin; J. Arvieux; James P. Ball; Shelton Beedoe; Elizabeth Beise; Louis Bimbot; Werner Boeglin; Herbert Breuer; Roger Carlini; Nicholas Chant; Samuel Danagoulian; K. Dow; Jean-Eric Ducret; Jim Dunne; Lars Ewell; L. Eyraud; C. Furget; Michel Garcon; Ron Gilman; Charles Glashausser; Paul Gueye; Kenneth Gustafsson; Kawtar Hafidi; A. Honegger; J. Jourdan; Serge Kox; Gerfried Kumbartzki; L. Lu; Allison Lung; Pete Markowitz; Justin McIntyre; David Meekins; F. Merchez; Joseph Mitchell; R. Mohring; S. Mtingwa; H. Mrktchyan; D. Pitz; Liming Qin; Ronald Ransome; J.-S. R'eal; Philip Roos; Paul Rutt; Reyad Sawafta; Stepan Stepanyan; Raphael Tieulent; E. Tomasi-Gustafsson; William Turchinetz; K. Vansyoc; J. Volmer; E. Voutier; Claude Williamson; Stephen Wood; Chen Yan; Jianguo Zhao; W. Zhao

2000-02-25

62

Hard breakup of two nucleons from the He3 nucleus  

NASA Astrophysics Data System (ADS)

We investigate a large angle photodisintegration of two nucleons from the He3 nucleus within the framework of the hard rescattering model (HRM). In the HRM a quark of one nucleon knocked out by an incoming photon rescatters with a quark of the other nucleon leading to the production of two nucleons with large relative momentum. Assuming the dominance of the quark-interchange mechanism in a hard nucleon-nucleon scattering, the HRM allows the expression of the amplitude of a two-nucleon breakup reaction through the convolution of photon-quark scattering, NN hard scattering amplitude, and nuclear spectral function, which can be calculated using a nonrelativistic He3 wave function. The photon-quark scattering amplitude can be explicitly calculated in the high energy regime, whereas for NN scattering one uses the fit of the available experimental data. The HRM predicts several specific features for the hard breakup reaction. First, the cross section will approximately scale as s-11. Second, the s11 weighted cross section will have the shape of energy dependence similar to that of s10 weighted NN elastic scattering cross section. Also one predicts an enhancement of the pp breakup relative to the pn breakup cross section as compared to the results from low energy kinematics. Another result is the prediction of different spectator momentum dependencies of pp and pn breakup cross sections. This is due to the fact that the same-helicity pp-component is strongly suppressed in the ground state wave function of He3. Because of this suppression the HRM predicts significantly different asymmetries for the cross section of polarization transfer NN breakup reactions for circularly polarized photons. For the pp breakup this asymmetry is predicted to be zero while for the pn it is close to (2)/(3).

Sargsian, Misak M.; Granados, Carlos

2009-07-01

63

Electromagnetic Structure of the Deuteron  

SciTech Connect

Recent high energy measurements of elastic ed scattering support the use of a relativistic theory based on an accurate description of the NN channel, but theory needed for an understanding of the high energy deuteron photodisintegration cross sections and polarized observables is not yet mature.

Franz Gross

2002-06-01

64

Deuteron and anti-deuteron production in ee collisions at the Z resonance  

NASA Astrophysics Data System (ADS)

Deuteron and anti-deuteron production in Z decays has been observed in the ALEPH experiment at LEP. The production rate of anti-deuterons is measured to be (5.9±1.8±0.5)×10 per hadronic Z decay in the anti-deuteron momentum range from 0.62 to 1.03 GeV/c. The coalescence parameter B, which characterizes the likelihood of anti-deuteron production, is measured to be 0.0033±0.0013 GeV in Z decays. These measurements indicate that the production of anti-deuterons is suppressed in ee collisions compared to that in pp and photoproduction collisions.

ALEPH Collaboration; Schael, S.; Barate, R.; Brunelière, R.; de Bonis, I.; Decamp, D.; Goy, C.; Jézéquel, S.; Lees, J.-P.; Martin, F.; Merle, E.; Minard, M.-N.; Pietrzyk, B.; Trocmé, B.; Bravo, S.; Casado, M. P.; Chmeissani, M.; Crespo, J. M.; Fernandez, E.; Fernandez-Bosman, M.; Garrido, Ll.; Martinez, M.; Pacheco, A.; Ruiz, H.; Colaleo, A.; Creanza, D.; de Filippis, N.; de Palma, M.; Iaselli, G.; Maggi, G.; Maggi, M.; Nuzzo, S.; Ranieri, A.; Raso, G.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Tricomi, A.; Zito, G.; Huang, X.; Lin, J.; Ouyang, Q.; Wang, T.; Xie, Y.; Xu, R.; Xue, S.; Zhang, J.; Zhang, L.; Zhao, W.; Abbaneo, D.; Barklow, T.; Buchmüller, O.; Cattaneo, M.; Clerbaux, B.; Drevermann, H.; Forty, R. W.; Frank, M.; Gianotti, F.; Hansen, J. B.; Harvey, J.; Hutchcroft, D. E.; Janot, P.; Jost, B.; Kado, M.; Mato, P.; Moutoussi, A.; Ranjard, F.; Rolandi, L.; Schlatter, D.; Teubert, F.; Valassi, A.; Videau, I.; Badaud, F.; Dessagne, S.; Falvard, A.; Fayolle, D.; Gay, P.; Jousset, J.; Michel, B.; Monteil, S.; Pallin, D.; Pascolo, J. M.; Perret, P.; Hansen, J. D.; Hansen, J. R.; Hansen, P. H.; Kraan, A. C.; Nilsson, B. S.; Kyriakis, A.; Markou, C.; Simopoulou, E.; Vayaki, A.; Zachariadou, K.; Blondel, A.; Brient, J.-C.; Machefert, F.; Rougé, A.; Videau, H.; Ciulli, V.; Focardi, E.; Parrini, G.; Antonelli, A.; Antonelli, M.; Bencivenni, G.; Bossi, F.; Capon, G.; Cerutti, F.; Chiarella, V.; Laurelli, P.; Mannocchi, G.; Murtas, G. P.; Passalacqua, L.; Kennedy, J.; Lynch, J. G.; Negus, P.; O'Shea, V.; Thompson, A. S.; Wasserbaech, S.; Cavanaugh, R.; Dhamotharan, S.; Geweniger, C.; Hanke, P.; Hepp, V.; Kluge, E. E.; Putzer, A.; Stenzel, H.; Tittel, K.; Wunsch, M.; Beuselinck, R.; Cameron, W.; Davies, G.; Dornan, P. J.; Girone, M.; Marinelli, N.; Nowell, J.; Rutherford, S. A.; Sedgbeer, J. K.; Thompson, J. C.; White, R.; Ghete, V. M.; Girtler, P.; Kneringer, E.; Kuhn, D.; Rudolph, G.; Bouhova-Thacker, E.; Bowdery, C. K.; Clarke, D. P.; Ellis, G.; Finch, A. J.; Foster, F.; Hughes, G.; Jones, R. W. L.; Pearson, M. R.; Robertson, N. A.; Sloan, T.; Smizanska, M.; van der Aa, O.; Delaere, C.; Leibenguth, G.; Lemaitre, V.; Blumenschein, U.; Hölldorfer, F.; Jakobs, K.; Kayser, F.; Müller, A.-S.; Renk, B.; Sander, H.-G.; Schmeling, S.; Wachsmuth, H.; Zeitnitz, C.; Ziegler, T.; Bonissent, A.; Coyle, P.; Curtil, C.; Ealet, A.; Fouchez, D.; Payre, P.; Tilquin, A.; Ragusa, F.; David, A.; Dietl, H.; Ganis, G.; Hüttmann, K.; Lütjens, G.; Männer, W.; Moser, H.-G.; Settles, R.; Villegas, M.; Wolf, G.; Boucrot, J.; Callot, O.; Davier, M.; Duflot, L.; Grivaz, J.-F.; Heusse, Ph.; Jacholkowska, A.; Serin, L.; Veillet, J.-J.; Azzurri, P.; Bagliesi, G.; Boccali, T.; Foà, L.; Giammanco, A.; Giassi, A.; Ligabue, F.; Messineo, A.; Palla, F.; Sanguinetti, G.; Sciabà, A.; Sguazzoni, G.; Spagnolo, P.; Tenchini, R.; Venturi, A.; Verdini, P. G.; Awunor, O.; Blair, G. A.; Cowan, G.; Garcia-Bellido, A.; Green, M. G.; Medcalf, T.; Misiejuk, A.; Strong, J. A.; Teixeira-Dias, P.; Clifft, R. W.; Edgecock, T. R.; Norton, P. R.; Tomalin, I. R.; Ward, J. J.; Bloch-Devaux, B.; Boumediene, D.; Colas, P.; Fabbro, B.; Lançon, E.; Lemaire, M.-C.; Locci, E.; Perez, P.; Rander, J.; Tuchming, B.; Vallage, B.; Litke, A. M.; Taylor, G.; Booth, C. N.; Cartwright, S.; Combley, F.; Hodgson, P. N.; Lehto, M.; Thompson, L. F.; Böhrer, A.; Brandt, S.; Grupen, C.; Hess, J.; Ngac, A.; Prange, G.; Borean, C.; Giannini, G.; He, H.; Putz, J.; Rothberg, J.; Armstrong, S. R.; Berkelman, K.; Cranmer, K.; Ferguson, D. P. S.; Gao, Y.; González, S.; Hayes, O. J.; Hu, H.; Jin, S.; Kile, J.; McNamara, P. A.; Nielsen, J.; Pan, Y. B.; von Wimmersperg-Toeller, J. H.; Wiedenmann, W.; Wu, J.; Wu, Sau Lan; Wu, X.; Zobernig, G.; Dissertori, G.

2006-08-01

65

Deuteron and anti-deuteron production in ee collisions at the Z resonance  

NASA Astrophysics Data System (ADS)

Deuteron and anti-deuteron production in Z decays has been observed in the ALEPH experiment at LEP. The production rate of anti-deuterons is measured to be (5.9±1.8±0.5)×10 per hadronic Z decay in the anti-deuteron momentum range from 0.62 to 1.03 GeV/ c. The coalescence parameter B, which characterizes the likelihood of anti-deuteron production, is measured to be 0.0033±0.0013 GeV in Z decays. These measurements indicate that the production of anti-deuterons is suppressed in ee collisions compared to that in pp and photoproduction collisions.

Schael, S.; Barate, R.; Brunelière, R.; de Bonis, I.; Decamp, D.; Goy, C.; Jézéquel, S.; Lees, J.-P.; Martin, F.; Merle, E.; Minard, M.-N.; Pietrzyk, B.; Trocmé, B.; Bravo, S.; Casado, M. P.; Chmeissani, M.; Crespo, J. M.; Fernandez, E.; Fernandez-Bosman, M.; Garrido, Ll.; Martinez, M.; Pacheco, A.; Ruiz, H.; Colaleo, A.; Creanza, D.; de Filippis, N.; de Palma, M.; Iaselli, G.; Maggi, G.; Maggi, M.; Nuzzo, S.; Ranieri, A.; Raso, G.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Tricomi, A.; Zito, G.; Huang, X.; Lin, J.; Ouyang, Q.; Wang, T.; Xie, Y.; Xu, R.; Xue, S.; Zhang, J.; Zhang, L.; Zhao, W.; Abbaneo, D.; Barklow, T.; Buchmüller, O.; Cattaneo, M.; Clerbaux, B.; Drevermann, H.; Forty, R. W.; Frank, M.; Gianotti, F.; Hansen, J. B.; Harvey, J.; Hutchcroft, D. E.; Janot, P.; Jost, B.; Kado, M.; Mato, P.; Moutoussi, A.; Ranjard, F.; Rolandi, L.; Schlatter, D.; Teubert, F.; Valassi, A.; Videau, I.; Badaud, F.; Dessagne, S.; Falvard, A.; Fayolle, D.; Gay, P.; Jousset, J.; Michel, B.; Monteil, S.; Pallin, D.; Pascolo, J. M.; Perret, P.; Hansen, J. D.; Hansen, J. R.; Hansen, P. H.; Kraan, A. C.; Nilsson, B. S.; Kyriakis, A.; Markou, C.; Simopoulou, E.; Vayaki, A.; Zachariadou, K.; Blondel, A.; Brient, J.-C.; Machefert, F.; Rougé, A.; Videau, H.; Ciulli, V.; Focardi, E.; Parrini, G.; Antonelli, A.; Antonelli, M.; Bencivenni, G.; Bossi, F.; Capon, G.; Cerutti, F.; Chiarella, V.; Laurelli, P.; Mannocchi, G.; Murtas, G. P.; Passalacqua, L.; Kennedy, J.; Lynch, J. G.; Negus, P.; O'Shea, V.; Thompson, A. S.; Wasserbaech, S.; Cavanaugh, R.; Dhamotharan, S.; Geweniger, C.; Hanke, P.; Hepp, V.; Kluge, E. E.; Putzer, A.; Stenzel, H.; Tittel, K.; Wunsch, M.; Beuselinck, R.; Cameron, W.; Davies, G.; Dornan, P. J.; Girone, M.; Marinelli, N.; Nowell, J.; Rutherford, S. A.; Sedgbeer, J. K.; Thompson, J. C.; White, R.; Ghete, V. M.; Girtler, P.; Kneringer, E.; Kuhn, D.; Rudolph, G.; Bouhova-Thacker, E.; Bowdery, C. K.; Clarke, D. P.; Ellis, G.; Finch, A. J.; Foster, F.; Hughes, G.; Jones, R. W. L.; Pearson, M. R.; Robertson, N. A.; Sloan, T.; Smizanska, M.; van der Aa, O.; Delaere, C.; Leibenguth, G.; Lemaitre, V.; Blumenschein, U.; Hölldorfer, F.; Jakobs, K.; Kayser, F.; Müller, A.-S.; Renk, B.; Sander, H.-G.; Schmeling, S.; Wachsmuth, H.; Zeitnitz, C.; Ziegler, T.; Bonissent, A.; Coyle, P.; Curtil, C.; Ealet, A.; Fouchez, D.; Payre, P.; Tilquin, A.; Ragusa, F.; David, A.; Dietl, H.; Ganis, G.; Hüttmann, K.; Lütjens, G.; Männer, W.; Moser, H.-G.; Settles, R.; Villegas, M.; Wolf, G.; Boucrot, J.; Callot, O.; Davier, M.; Duflot, L.; Grivaz, J.-F.; Heusse, Ph.; Jacholkowska, A.; Serin, L.; Veillet, J.-J.; Azzurri, P.; Bagliesi, G.; Boccali, T.; Foà, L.; Giammanco, A.; Giassi, A.; Ligabue, F.; Messineo, A.; Palla, F.; Sanguinetti, G.; Sciabà, A.; Sguazzoni, G.; Spagnolo, P.; Tenchini, R.; Venturi, A.; Verdini, P. G.; Awunor, O.; Blair, G. A.; Cowan, G.; Garcia-Bellido, A.; Green, M. G.; Medcalf, T.; Misiejuk, A.; Strong, J. A.; Teixeira-Dias, P.; Clifft, R. W.; Edgecock, T. R.; Norton, P. R.; Tomalin, I. R.; Ward, J. J.; Bloch-Devaux, B.; Boumediene, D.; Colas, P.; Fabbro, B.; Lançon, E.; Lemaire, M.-C.; Locci, E.; Perez, P.; Rander, J.; Tuchming, B.; Vallage, B.; Litke, A. M.; Taylor, G.; Booth, C. N.; Cartwright, S.; Combley, F.; Hodgson, P. N.; Lehto, M.; Thompson, L. F.; Böhrer, A.; Brandt, S.; Grupen, C.; Hess, J.; Ngac, A.; Prange, G.; Borean, C.; Giannini, G.; He, H.; Putz, J.; Rothberg, J.; Armstrong, S. R.; Berkelman, K.; Cranmer, K.; Ferguson, D. P. S.; Gao, Y.; González, S.; Hayes, O. J.; Hu, H.; Jin, S.; Kile, J.; McNamara, P. A.; Nielsen, J.; Pan, Y. B.; von Wimmersperg-Toeller, J. H.; Wiedenmann, W.; Wu, J.; Wu, Sau Lan; Wu, X.; Zobernig, G.; Dissertori, G.; Aleph Collaboration

66

The naming of the deuteron  

NASA Astrophysics Data System (ADS)

The naming of the deuteron involved a protracted debate between 1933 and 1935. The principal protagonists were Harold C. Urey, Gilbert N. Lewis, Ernest O. Lawrence, and Ernest Rutherford, but others on both sides of the Atlantic entered the fray as well. This paper examines the arguments and issues that emerged in the debate, and the process by which agreement was finally achieved on the name for this new particle.

Stuewer, Roger H.

1986-03-01

67

Deuteron photodisintegration with polarized lasers  

E-print Network

A model independent theoretical analysis of recent experimental data on deuteron photodisintegration with polarized laser beams is presented. We find that it is important to distinguish between the three isovector E1 amplitudes $E1_v^j$ in reaction channels with total angular momentum $j=0,1,2$ and that the isoscalar M1 amplitude $M1_s$ is non-zero in the photon energy range $3.5 MeV < E_\\gamma < 10 MeV$

G. Ramachandran; S. P. Shilpashree

2011-04-07

68

Nonlocality in deuteron stripping reactions.  

PubMed

We propose a new method for the analysis of deuteron stripping reactions, A(d,p)B, in which the nonlocality of nucleon-nucleus interactions and three-body degrees of freedom are accounted for in a consistent way. The model deals with equivalent local nucleon potentials taken at an energy shifted by ?40??MeV from the "E(d)/2" value frequently used in the analysis of experimental data, where E(d) is the incident deuteron energy. The "E(d)/2" rule lies at the heart of all three-body analyses of (d, p) reactions performed so far with the aim of obtaining nuclear structure properties such as spectroscopic factors and asymptotic normalization coefficients that are crucial for our understanding of nuclear shell evolution in neutron- and proton-rich regions of the nuclear periodic table and for predicting the cross sections of stellar reactions. The large predicted shift arises from the large relative kinetic energy of the neutron and proton in the incident deuteron in those components of the n+p+A wave function that dominate the (d, p) reaction amplitude. The large shift reduces the effective d-A potentials and leads to a change in predicted (d, p) cross sections, thus affecting the interpretation of these reactions in terms of nuclear structure. PMID:25166525

Timofeyuk, N K; Johnson, R C

2013-03-15

69

Determination of Deuteron Beam Polarizations at COSY  

E-print Network

The vector and tensor polarizations of a deuteron beam have been measured using elastic deuteron-carbon scattering at 75.6 MeV and deuteron-proton scattering at 270 MeV. After acceleration to 1170 MeV inside the COSY ring, the polarizations of the deuterons were checked by studying a variety of nuclear reactions using a cluster target at the ANKE magnet spectrometer placed at an internal target position of the storage ring. All these measurements were consistent with the absence of depolarization during acceleration and provide a number of secondary standards that can be used in subsequent experiments at the facility.

D. Chiladze; A. Kacharava; F. Rathmann; C. Wilkin; S. Barsov; J. Carbonell; S. Dymov; R. Engels; P. D. Eversheim; R. Gebel; V. Glagolev; K. Grigoriev; D. Gusev; M. Hartmann; F. Hinterberger; V. Hejny; A. Khoukaz; I. Keshelashvili; H. R. Koch; V. Komarov; P. Kulessa; A. Kulikov; A. Lehrach; B. Lorentz; G. Macharashvili; R. Maier; Y. Maeda; R. Menke; T. Mersmann; S. Merzliakov; M. Mikirtytchiants; S. Mikirtytchiants; A. Mussgiller; M. Nioradze; H. Ohm; D. Prasuhn; H. Rohdjess; R. Schleichert; H. Seyfarth; E. Steffens; H. J. Stein; H. Stroeher; S. Trusov; K. Ulbrich; Yu. Uzikov; A. Wronska; S. Yaschenko

2005-11-30

70

Exclusive Photoproduction of K+?*-(n) Off Deuteron  

NASA Astrophysics Data System (ADS)

We are using the CEBAF Large Acceptance Spectrometer (CLAS) to study the exclusive photoproduction of K+?*- (1385) off the deuteron. It will be the first published total cross section of this reaction channel. We show the preliminary results of the total cross section, while we present all the key steps of achieving it. In order to study the reaction mechanism, we also study and show the angular distribution in the Gottfried-Jackson frame.

Lu, Haiyun; Graham, Lewis; Zhao, Zhiwen; Park, Kijun; Gothe, Ralf

2010-08-01

71

The Effect of Surfactants on the Breakup of an Axisymmetric Laminar Jet  

NASA Astrophysics Data System (ADS)

The breakup of a laminar axisymmetric jet is a well-studied fluid dynamics phenomenon, first studied by Savart (1833) and Rayleigh (1879). Many papers have been published over the years describing the theory of jet breakup, such as the paper by Tomotika (1935). More recently, many studies have been performed using various computational simulations to better understand the mechanics of jet breakup, notable among these are Homma et al. (2006). Despite the extensive literature on the topic, the impact of surface active agents on jet breakup has received limited attention, whether due to the system's inherent complexity or a poor understanding of the mechanics of the action of surface active agents themselves. In this study, the drop size distribution and jet breakup length resulting from the breakup of liquid jet systems were studied experimentally. Jets were formed by forcing a fluid through a narrow capillary using pneumatic pressure. Experiments involving oil-water jets with aqueous surfactants were performed. Several distinct regimes were identified based on hydrodynamic and physicochemical conditions. Jet length was found to increase with surfactant concentration, while droplet diameter was found to decrease (dependent on jet regime). A Semiempirical model to predict the breakup length of Jets in the presence of surfactants is also proposed.

Walker, Justin; Calabrese, Richard

2011-11-01

72

Spin-manipulating polarized deuterons  

SciTech Connect

Spin dynamics of polarized deuteron beams near depolarization resonances, including a new polarization preservation concept based on specially-designed multiple resonance crossings, has been tested in a series of experiments in the COSY synchrotron. Intricate spin dynamics with sophisticated pre-programmed patterns as well as effects of multiple crossings of a resonance were studied both theoretically and experimentally with excellent agreement. Possible applications of these results to preserve, manipulate and spin-flip polarized beams in synchrotrons and storage rings are discussed.

Morozov, V S; Krisch, A D; Leonova, M A; Raymond, R S; Sivers, D W; Wong, V K; Hinterberger, F; Kondratenko, A M

2011-03-01

73

High Energy Break-Up of Few-Nucleon Systems  

E-print Network

We discus recent developments in theory of high energy two-body break-up reactions of few-nucleon systems. The characteristics of these reactions are such that the hard two-body quasielastic subprocess can be clearly separated from the accompanying soft subprocesses. We discuss in details the hard rescattering model (HRM) in which hard photodisintegration develops in two stages. At first, photon knocks-out an energetic quark which rescatters subsequently with a quark of the other nucleon. The latter provides a mechanism of sharing the initial high momentum of the photon by the outgoing two nucleons. Within HRM we discuss hard break-up reactions involving $^2D$ and $^3He$ targets. Another development of HRM is the prediction of new helicity selection mechanism for hard two-body reactions, which was apparently confirmed in the recent JLab experiment.

Misak M. Sargsian

2008-01-14

74

High Energy Break-Up of Few-Nucleon Systems  

NASA Astrophysics Data System (ADS)

We discus recent developments in theory of high energy two-body break-up reactions of few-nucleon systems. The characteristics of these reactions are such that the hard two-body quasielastic subprocess can be clearly separated from the accompanying soft subprocesses. We discuss in details the hard rescattering model (HRM) in which hard photodisintegration develops in two stages. At first, photon knocks-out an energetic quark which rescatters subsequently with a quark of the other nucleon. The latter provides a mechanism of sharing the initial high momentum of the photon by the outgoing two nucleons. Within HRM we discuss hard break-up reactions involving 2D and 3He targets. Another development of HRM is the prediction of new helicity selection mechanism for hard two-body reactions, which was apparently confirmed in the recent JLab experiment.

Sargsian, Misak

2008-03-01

75

Measurement of T20,,90... in the 1 He reaction below deuteron breakup threshold  

E-print Network

significant source of background in the random neutron subtracted photon spectrum resulted from the photon and the epoxy adhesive at the entrance and exit foils. The cell was filled through a molecular sieve cold trap cooled to 77 K. A second cold trap, also at 77 K, was open to the cell after filling. A typical time

Knutson, Lynn

76

Cold Nuclear Matter Effects on J/Psi as Constrained by Deuteron-Gold Measurements at sqrt(s_NN) = 200 GeV  

E-print Network

We present a new analysis of J/psi production yields in deuteron-gold collisions at sqrt(s_NN) = 200 GeV using data taken by the PHENIX experiment in 2003 and previously published in [S.S. Adler et al., Phys. Rev. Lett 96, 012304 (2006)]. The high statistics proton-proton J/psi data taken in 2005 is used to improve the baseline measurement and thus construct updated cold nuclear matter modification factors R_dAu. A suppression of J/psi in cold nuclear matter is observed as one goes forward in rapidity (in the deuteron-going direction), corresponding to a region more sensitive to initial state low-x gluons in the gold nucleus. The measured nuclear modification factors are compared to theoretical calculations of nuclear shadowing to which a J/psi (or precursor) break-up cross-section is added. Breakup cross sections of sigma_breakup = 2.8^[+1.7_-1.4] (2.2^[+1.6_-1.5]) mb are obtained by fitting these calculations to the data using two different models of nuclear shadowing. These breakup cross section values are consistent within large uncertainties with the 4.2 +/- 0.5 mb determined at lower collision energies. Projecting this range of cold nuclear matter effects to copper-copper and gold-gold collisions reveals that the current constraints are not sufficient to firmly quantify the additional hot nuclear matter effect.

PHENIX Collaboration; A. Adare

2007-11-25

77

Elastic scattering of deuterons by carbon  

NASA Technical Reports Server (NTRS)

Deuteron-carbon elastic scattering is studied within the framework of the Glauber approximation. The full Glauber multiple scattering series is evaluated with simplified nuclear wave functions. An approximation in which deuteron-nucleus scattering is expressed in terms of nucleon-nucleus scattering amplitudes is shown to be accurate for small momentum transfers. The effects of the Coulomb field and the deuteron D state are investigated. The impressive fit to the 650 MeV d-(C-12) elastic scattering data, obtained in a recent calculation, is shown to be due to additional approximations made in that analysis.

Varma, G. K.; Franco, V.

1977-01-01

78

Polarization of the neutron induced from hadronic weak interactions in the photo-disintegration of the deuteron  

E-print Network

New observables with which we can study the two-nucleon weak interactions at low energies are considered. In the breakup of the deuteron by photons, polarization of outgoing neutrons can depend on the parity-violating component of two-nucleon interactions. We express the parity-violating polarization in general forms, and perform numerical calculations with a pionless effective field theory. The theory has unknown parity-violating low energy constants, and the results are expressed in linear combination of them. We discuss the results and their implication to the understanding of the hadronic weak interactions.

J. W. Shin; C. H. Hyun; S. -I. Ando; S. W. Hong

2013-03-19

79

Deuteron elastic scattering from the tin isotopes  

Microsoft Academic Search

Angular distributions are presented for the elastic scattering of 20 MeV deuterons from 112,118,124Sn and of 27 MeV deuterons from 112,118,119,124Sn. Satisfactory fits to the data were obtained using both the standard optical model and the reformulated optical model of Greenlees, Pyle and Tang. Comparison with potentials obtained from proton elastic scattering showed consistently smaller mean square radii for the

Lesley A. Winsborrow; G. L. Thomas; C. F. Coleman; T. W. Conlon

1972-01-01

80

History and consequences of on-orbit break-ups  

NASA Astrophysics Data System (ADS)

Since 1961 more than eighty satellite fragmentation events have been identified. These occurrences are responsible for one-third of all man-made space objects cataloged since Sputnik 1 and constitute one-half of all satellites currently in orbit about the Earth. The two known mechanisms of artificial satellite break-ups are accidental (e.g. propulsion-related malfunctions) and deliberate (e.g. military-related activities) on-board explosions. However, the causes of half of all satellite break-ups remain undetermined. The steady increase in the near-Earth space debris population raises legitimate concerns about the mounting probability of satellite-satellite collisions. The limitations of ground-based radars suggest that the true population of Earth-orbiting satellites may be many times that officially registered. Recent laboratory tests indicate that a large number of potentially lethal fragments would be liberated during a hypervelocity collision in space.

Johnson, N. L.

81

Gondwana breakup and plate kinematics: Business as usual  

NASA Astrophysics Data System (ADS)

A tectonic model of the Weddell Sea is built by composing a simple circuit with optimized rotations describing the growth of the South Atlantic and SW Indian oceans. The model independently and accurately reproduces the consensus elements of the Weddell Sea's spreading record and continental margins, and offers solutions to remaining controversies there. At their present resolutions, plate kinematic data from the South Atlantic and SW Indian oceans and Weddell Sea rule against the proposed, but controversial, independent movements of small plates during Gondwana breakup that have been attributed to the presence or impact of a mantle plume. Hence, although supercontinent breakup here was accompanied by extraordinary excess volcanism, there is no indication from plate kinematics that the causes of that volcanism provided a unique driving mechanism for it.

Eagles, Graeme; Vaughan, Alan P. M.

2009-05-01

82

Resonant breakup of {sup 19}C on a proton target  

SciTech Connect

The resonant breakup of {sup 19}C on a proton target at 70 MeV/nucleon is analyzed using Faddeev-Alt, Grassberger, Sandhas (Faddeev-AGS) and continuum-discretized coupled-channels (CDCC) reaction frameworks, where in both cases a three-body model ({sup 18}C+n+p) for the reaction is considered. Taking a {sup 18}C + p potential from a global nucleon-nucleus parametrization and a L-independent Gaussian proton-neutron potential, both methods provide very similar results for the calculated observables. However, when this simplified proton-neutron potential is replaced by the more realistic CD-Bonn potential, the breakup cross section, calculated with the Faddeev AGS formalism, decreases by almost one order of magnitude, largely underestimating the experimental data. From this calculation, we conclude that, within a core + valence neutron model, the single-particle mechanism gives a negligible contribution to the calculated resonant breakup and therefore core-excitation mechanisms should be taken into account.

Crespo, R. [Centro de Fisica Nuclear, Universidade de Lisboa, Av. Prof. Gama Pinto 2, P-1649-003 Lisboa (Portugal); Departamento de Fisica, Instituto Superior Tecnico, Taguspark, Av. Prof. Cavaco Silva, Taguspark, P-2780-990 Porto Salvo, Oeiras (Portugal); Rodriguez-Gallardo, M. [Centro de Fisica Nuclear, Universidade de Lisboa, Av. Prof. Gama Pinto 2, P-1649-003 Lisboa (Portugal); Instituto de Estructura de la Materia, CSIC, Serrano 123, E-28006 Madrid (Spain); Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Sevilla, Apartado 1065, E-41080 Sevilla (Spain); Moro, A. M. [Departamento de Fisica Atomica, Molecular y Nuclear, Universidad de Sevilla, Apartado 1065, E-41080 Sevilla (Spain); Deltuva, A.; Cravo, E.; Fonseca, A. C. [Centro de Fisica Nuclear, Universidade de Lisboa, Av. Prof. Gama Pinto 2, P-1649-003 Lisboa (Portugal)

2011-05-15

83

^8B Breakup, the Longstanding Puzzle  

NASA Astrophysics Data System (ADS)

The cross section of ^8B breakup reaction provides an indirect estimate of the ^7Be(p, ?)^8B reaction rate. This reaction is important because of its connection to to the solar neutrino problem. At low (stellar) energies the ^7Be(p, ?) ^8B reaction is dominated by the electric dipole transition (E1), while the ^8B breakup reaction rate has a significant contribution from the quadrupole transition (E2). To obtain the astrophysical S-factor S17(E) from different ^8B breakup experiments we must understand the contribution of E2 to the measured observables. Previous model calculations could not provide an unambiguous estimate of E2. In our present work we use XCDCC (Extended Continuous Discretized Coupled Channel) to explore the impact of the core (^7Be) spin, deformation and excitation to ^8B breakup.

Pervin, Muslema; Nunes, Filomena

2011-10-01

84

Deuteron production in p-Be interactions at 450 GeV/c and the coalescing model  

E-print Network

The analysis of the deuteron production in p--Be interactions at 450 GeV/c taken by the NA56/SPY experiment at CERN SPS is presented. In the framework of the coalescence model, the coalescence factor $\\kappa$ is determined as $(0.79 \\pm 0.05 \\pm 0.13) \\times 10^{-2}$. Our results disfavour the hypothesis that coalescence be the dominant mechanism for deuteron production in $p+Be$ interactions at low $p_T$.

M. Bonesini; for the HARP Collaboration

2007-12-28

85

Generation and Breakup of Worthington Jets After Cavity Collapse  

E-print Network

Helped by the careful analysis of their experimental data, Worthington (1897) described roughly the mechanism underlying the formation of high-speed jets ejected after the impact of an axisymmetric solid on a liquid-air interface. In this work we combine detailed boundary-integral simulations with analytical modeling to describe the formation and break-up of such Worthington jets in two common physical systems: the impact of a circular disc on a liquid surface and the release of air bubbles from an underwater nozzle. We first show that the jet base dynamics can be predicted for both systems using our earlier model in Gekle, Gordillo, van der Meer and Lohse. Phys. Rev. Lett. 102 (2009). Nevertheless, our main point here is to present a model which allows us to accurately predict the shape of the entire jet. Good agreement with numerics and some experimental data is found. Moreover, we find that, contrarily to the capillary breakup of liquid cylinders in vacuum studied by Rayleigh, the breakup of stretched liqu...

Gekle, Stephan

2009-01-01

86

Breakup of viscous liquid sheets  

SciTech Connect

In many industrial processes, it is desirable to use a spray of drops rather than a bulk liquid. Examples of applications include gas turbines, industrial furnaces, diesel and gasoline engines, cooling sprays, and crop sprays. A study of the breakup of planar viscous liquid sheets subjected to gas flow on both sides were conducted. A linear spatial stability analysis was used to determine the instability wave characteristics. The analysis included the effects of liquid properties such as viscosity, density, and surface tension; the gas was treated as inviscid. Dispersion relations were obtained relating the wave growth rates to the frequency and other flow variables. The wave characteristics were determined by numerical solution of the governing dispersion relations for a wide range of operating conditions. In all cases, the gas velocity was found to be destabilizing; increases in the liquid density, viscosity, and surface tension were all found to have stabilizing effects. When the liquid sheet was exposed to unequal gas velocities, the wave propagation characteristics were found to be altered from the case of equal gas velocities.

Witherspoon, W.; Parthasarathy, R.N. [Univ. of Oklahoma, Norman, OK (United States). School of Aerospace and Mechanical Engineering

1996-10-01

87

Relativistically invariant analysis of polarization effects in exclusive deuteron electrodisintegration process  

E-print Network

A general formalism for the calculation of the differential cross section and polarization observables, for the process of deuteron electrodisintegration, is developed in the framework of relativistic impulse approximation. A detailed analysis of the general structure of the differential cross section and polarization observables for the $e^-+d\\to e^-+n+p$ reaction is derived, using the formalism of the structure functions. The obtained expressions have a general nature and they hold in the one--photon--exchange mechanism, assuming P--invariance of the hadron electromagnetic interaction. The model of relativistic impulse approximation is introduced and the final state interaction is taken into account by means of the unitarization of the helicity amplitudes. A detailed description of the unitarization procedure is also presented. Using different parametrizations of the deuteron wave functions, the following polarization observables are calculated in the kinematical region of quasi--elastic deuteron electrodisintegration: the asymmetry for the scattering of longitudinally polarized electrons on a polarized deuteron target, the proton and neutron polarizations (for longitudinally polarized electron beam or vector--polarized deuteron target). The sensitivity to the neutron electric form factor is also thorougly investigated. The predictions of the model are compared with the results of recent polarization measurements and a good agreement with the existing experimental data has been obtained.

G. I. Gakh; A. P. Rekalo; Egle Tomasi-Gustafsson

2004-12-08

88

A discussion of deuteron transverse charge densities  

E-print Network

The deuteron transverse charge density $\\rho_C(b)$ is the two-dimensional Fourier transform of its charge form factor in the impact space. We show that different parameterizations of the charge form factors provide different $\\rho_C(b)$, in particular at the central value of impact parameter ($b=0$), although all the parameterizations can well reproduce the form factors in the region of small $Q^2$. In addition, we also check the explicit contributions from the different coordinate intervals of the deuteron wave function to its root-mean-square radius.

Cuiying Liang; Yubing Dong; Weihong Liang

2014-06-10

89

A Discussion of Deuteron Transverse Charge Densities  

NASA Astrophysics Data System (ADS)

The deuteron transverse charge density ?C(b) is the two-dimensional Fourier transform of its charge form factor in the impact space. We show that different parameterizations of the charge form factors provide different ?C(b), in particular at the central value of impact parameter (b = 0), although all the parameterizations can well reproduce the form factors in the region of small Q2. In addition, we also check the explicit contributions from the different coordinate intervals of the deuteron wave function to its root-mean-square radius.

Liang, Cui-Ying; Dong, Yu-Bing; Liang, Wei-Hong

2014-09-01

90

A discussion of deuteron transverse charge densities  

E-print Network

The deuteron transverse charge density $\\rho_C(b)$ is the two-dimensional Fourier transform of its charge form factor in the impact space. We show that different parameterizations of the charge form factors provide different $\\rho_C(b)$, in particular at the central value of impact parameter ($b=0$), although all the parameterizations can well reproduce the form factors in the region of small $Q^2$. In addition, we also re-check the contributions from the different coordinate intervals of the deuteron wave function to its root-mean-square radius.

Liang, Cuiying; Liang, Weihong

2014-01-01

91

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

NASA Astrophysics Data System (ADS)

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 (<0.1). Findings and conclusions. Present experimental results show that the column waves along the 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 field inside the liquid jet consisted of a counter-rotating vortex pair that was not observed in column and shear breakup. Finally, phenomenological analyses were effective to understand the conditions for breakup regime transitions.

Ng, Chee-Loon

92

Pion-less Effective Field Theory on Low-Energy Deuteron Electro-Disintegration  

E-print Network

In view of its relation to Big-Bang Nucleo-Synthesis and a reported discrepancy between nuclear models and data taken at S-DALINAC, electro-induced deuteron break-up 2H(e,e' p)n is studied at momentum transfer qelectric dipole currents and at NLO for magnetic ones converges order-by-order better than quantitatively predicted and contains no free parameter. It is at this order determined by simple, well-known observables. Decomposing the doubly differential cross-section into the longitudinal-plus-transverse (L+T), transverse-transverse (TT) and longitudinal-transverse interference (LT) terms, we find excellent agreement with a potential-model calculation by Arenh"ovel et al using the Bonn potential. Theory and data also agree well on \\sigma_{L+T}. There is however no space on the theory-side for the discrepancy of up to 30%, 3-\\sigma between theory and experiment in \\sigma_{LT}. From universality, we conclude that no theoretical approach with the correct deuteron asymptotic wave-function can explain the data. Un-determined short-distance contributions that could affect \\sigma_{LT} enter only at high orders, i.e. at the few-percent level. We notice some issues with the kinematics and normalisation of the data reported.

Stefan Christlmeier; Harald W. Griesshammer

2008-03-09

93

Pion-less effective field theory on low-energy deuteron electrodisintegration  

NASA Astrophysics Data System (ADS)

In view of its relation to Big Bang nucleosynthesis and a reported discrepancy between nuclear models and data taken at S-DALINAC, electro-induced deuteron breakup 2H(e,e'p)n is studied at momentum transfer q<100 MeV and close to threshold in the low-energy nuclear effective field theory without dynamical pions, EFT(?/). The result at next-to-next-to-leading order (NLO2) for electric dipole currents and at next-to-leading order (NLO) for magnetic ones converges order-by-order better than quantitatively predicted and contains no free parameter. It is at this order determined by simple, well-known observables. Decomposing the triple differential cross section into the longitudinal-plus-transverse (L+T), transverse-transverse (TT), and longitudinal-transverse interference (LT) terms, we find excellent agreement with a potential-model calculation by Arenhövel and co-workers, based on the Bonn potential. Theory and data also agree well on ?L+T. There is however no space on the theory side for the discrepancy of up to 30%(3?) between theory and experiment in ?LT. From universality of EFT(?/), we conclude that no theoretical approach with the correct deuteron asymptotic wave function can explain the data. Undetermined short-distance contributions that could affect ?LT enter only at high orders (i.e., at the few-percent level). We notice some issues with the kinematics and normalization of the data reported.

Christlmeier, Stefan; Grießhammer, Harald W.

2008-06-01

94

Coulomb and nuclear breakup of 8B  

NASA Astrophysics Data System (ADS)

The cross sections for the (8B,7Be-p) breakup reaction on 58Ni and 208Pb targets at the beam energies of 25.8 MeV and 415 MeV have been calculated within a one-step prior-form distorted-wave Born approximation. The relative contributions of Coulomb and nuclear breakup of dipole and quadrupole multipolarities as well as their interference have been determined. The nuclear breakup contributions are found to be substantial in the angular distributions of the 7Be fragment for angles in the range of 30°-80° at 25.8 MeV beam energy. The Coulomb-nuclear interference terms make the dipole cross section larger than that of quadrupole even at this low beam energy. However, at the incident energy of 415 MeV, these effects are almost negligible in the angular distributions of the (7Be-p) coincidence cross sections at angles below 4°.

Shyam, R.; Thompson, I. J.

1999-05-01

95

Accelerated deuterons in cluster-fusion experiments  

SciTech Connect

The collisional interaction of heavy-water clusters with TiD has been studied theoretically via three independent methods with the aim of estimating cluster-fusion yields. Particular attention was paid to multiple wide-angle-scattering processes between deuterons and heavy beam or target atoms. In order to achieve adequate statistics in molecular-dynamics simulations, the elastic-scattering cross section was enhanced by, roughly, increasing the deuteron charge at constant mass. Deuteron spectra were then determined by extrapolation to {ital Z}=1. The validity of the procedure was confirmed by comparison with simulations using unscaled interaction potentials. Monte Carlo simulations were also performed, using a code that incorporates target motion and allows for larger cluster and target size. Cross sections for double wide-angle-scattering events (Fermi shuttles) were computed directly. By all three methods we find clear evidence that deuterons are accelerated far beyond the limits imposed by single-scattering kinematics. We find exponential tails with slopes approximately inversely proportional to the incident energy per cluster atom. Estimated fusion yields increase very strongly with the energy per beam atom and lie 8 to 18 orders of magnitude below those reported experimentally.

Hautala, M.; Pan, Z.; Sigmund, P. (Physics Department, Odense University, DK-5230 Odense M (Denmark))

1991-12-01

96

Numerical simulation of turbulent jet primary breakup in Diesel engines  

E-print Network

Numerical simulation of turbulent jet primary breakup in Diesel engines Peng Zeng1 Marcus Herrmann" IRMA Strasbourg, 23.Jan.2008 #12;Introduction DNS of Primary Breakup in Diesel Injection Phase Transition Modeling Turbulence Modeling Summary Outline 1 Introduction 2 DNS of Primary Breakup in Diesel

Helluy, Philippe

97

Incorporation of Aggregate Breakup in the Simulation of Orthokinetic Coagulation  

Microsoft Academic Search

The agglomeration and breakup of floc aggregates formed in orthokinetic coagulation is examined. By considering local flow strain-rate, a breakup rate kernel is derived based on flow-induced normal stresses. The new breakup kernel is included in a population size class balance for floc aggregates. The resulting population balance was solved numerically over a wide range of parameters to obtain a

Timothy A Kramer; Mark M Clark

1999-01-01

98

Internal stresses and breakup of rigid isostatic aggregates in homogeneous and isotropic turbulence  

E-print Network

By characterising the hydrodynamic stresses generated by statistically homogeneous and isotropic turbulence in rigid aggregates, we estimate theoretically the rate of turbulent breakup of colloidal aggregates and the size distribution of the formed fragments. The adopted method combines Direct Numerical Simulation of the turbulent field with a Discrete Element Method based on Stokesian dynamics. In this way, not only the mechanics of the aggregate is modelled in detail, but the internal stresses are evaluated while the aggregate is moving in the turbulent flow. We examine doublets and cluster-cluster isostatic aggregates, where the failure of a single contact leads to the rupture of the aggregate and breakup occurs when the tensile force at a contact exceeds the cohesive strength of the bond. Due to the different role of the internal stresses, the functional relationship between breakup frequency and turbulence dissipation rate is very different in the two cases. In the limit of very small and very large valu...

De Bona, Jeremias; Vanni, Marco

2014-01-01

99

Beam breakup instabilities in dielectric structures  

Microsoft Academic Search

We report on the experimental and numerical investigation of beam breakup (BBU) effects in dielectric structures resulting from parasitic wakefields. The experimental program focuses on measurements of BBU in a number of wakefield devices: (a) a 26 GHz power extraction structure; (b) a high gradient dielectric wakefield accelerator; (c) a wakefield structure driven by a high current ramped bunch train

A. Kanareykin; C. Jing; P. Schoessow; J. G. Power; W. Gai

2007-01-01

100

El Nino signature in Alaskan river breakups  

E-print Network

A signature of El Nino-Southern Oscillation is found in the historical dataset of the Alaskan Tanana river breakups where the average ice breaking day is found to anticipate of about 3.4 days when conditioned over El Nino years. This results represents a statistically significant example of ENSO teleconnection on regions remote from tropical Pacific.

Boffetta, G

2011-01-01

101

[Defence mechanisms and coping strategies in men and women: a comparative and structural study based on the artistic production of people suffering from a break-up of their life project].  

PubMed

A comparative study of men and women suffering from a break-up of their life project allowed us examining the typically female and male manners to cope with trauma, anxiety, guilt, depression and internal destructivity. In a first stage, an exploratory study was focussed on 206 subjects, belonging to several clinical subgroups: people living in great precarity and long-term unemployed people, asylum seekers and refugees, drug addicts, prisoners and people coming out of prison. Secondly, arts therapeutic sessions were proposed with the aim of helping the participants finding an outlet to their situation. The artistic production (drawings and stories induced by music) was analysed with the help of original rating scales, constructed in a phenomenological and structural perspective. We will present a synthesis of our qualitative observations, as well as some results of typological and structural studies, computed with the help of non parametric statistical procedures on the data of N = 93 participants. The results allow us pointing to gender differences and defining typically male and female coping styles. Differential indications for psychotherapy can be extracted from these analyses. PMID:24437072

Schiltz, L; Ciccarello, A; Ricci-Boyer, L; Schiltz, J

2013-01-01

102

Deuteron electric quadrupole and octupole polarizabilities  

E-print Network

The direct transition-matrix approach to determination of the electric polarizabilities of quantum bound systems developed in my recent work is applied to study the electric multipole polarizabilities of a two-particle bound complex with a central interaction between the particles. Expressions for the electric quadrupole and octupole polarizabilities of the deuteron are derived and their values in the case of the S-wave separable interaction potential are calculated.

V. F. Kharchenko

2012-09-10

103

Nuclear break-up of 11Be  

E-print Network

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.

V. Lima; J. A. Scarpaci; D. Lacroix; Y. Blumenfeld; C. Bourgeois; M. Chabot; Ph. Chomaz; P. Desesquelles; V. Duflot; J. Duprat; M. Fallot; N. Frascaria; S. Grevy; D. Guillemaud-Mueller; P. Roussel-Chomaz; H. Savajols; O. Sorlin

2007-09-25

104

Coupled map lattice model of jet breakup  

SciTech Connect

An alternative approach is described to evaluate the statistical nature of the breakup of shaped charge liners. Experimental data from ductile and brittle copper jets are analyzed in terms of velocity gradient, deviation of {Delta}V from linearity, R/S analysis, and the Hurst exponent within the coupled map lattice model. One-dimensional simulations containing 600 zones of equal mass and using distinctly different force-displacement curves are generated to simulate ductile and brittle behavior. A particle separates from the stretching jet when an element of material reaches the failure criterion. A simple model of a stretching rod using brittle, semi-brittle, and ductile force-displacement curves is in agreement with the experimental results for the Hurst exponent and the phase portraits and indicates that breakup is a correlated phenomenon.

Minich, R W; Schwartz, A J; Baker, E L

2001-01-25

105

Hydrodynamic and aerodynamic breakup of liquid sheets  

NASA Technical Reports Server (NTRS)

The effect of hydrodynamic, aerodynamic and liquid surface forces on the mean drop diameter of water sprays that are produced by the breakup of nonswirling and swirling water sheets in quiescent air and in airflows similar to those encountered in gas turbine combustors is investigated. The mean drop diameter is used to characterize fuel sprays and it is a very important factor in determining the performance and exhaust emissions of gas turbine combustors.

Ingebo, R.

1982-01-01

106

Beam Breakup Effects in Dielectric Based Accelerators  

SciTech Connect

The dynamics of the beam in structure-based wakefield accelerators leads to beam stability issues not ordinarily found in other machines. In particular, the high current drive beam in an efficient wakefield accelerator loses a large fraction of its energy in the decelerator structure, resulting in physical emittance growth, increased energy spread, and the possibility of head-tail instability for an off axis beam, all of which can lead to severe reduction of beam intensity. Beam breakup (BBU) effects resulting from parasitic wakefields provide a potentially serious limitation to the performance of dielectric structure based wakefield accelerators as well. We report on experimental and numerical investigation of BBU and its mitigation. The experimental program focuses on BBU measurements at the AWA facility in a number of high gradient and high transformer ratio wakefield devices. New pickup-based beam diagnostics will provide methods for studying parasitic wakefields that are currently unavailable. The numerical part of this research is based on a particle-Green's function beam breakup code we are developing that allows rapid, efficient simulation of beam breakup effects in advanced linear accelerators. The goal of this work is to be able to compare the results of detailed experimental measurements with the accurate numerical results and to design an external FODO channel for the control of the beam in the presence of strong transverse wakefields.

Schoessow, P.; Kanareykin, A. [Euclid Techlabs LLC, Solon, OH 44139 (United States); Jing, C. [Euclid Techlabs LLC, Solon, OH 44139 (United States); Argonne National Laboratory, IL (United States); Kustov, A. [Dynamics Software, Helsinki (Finland); Altmark, A. [Electrotechnical University Eltech 'LETI', St. Petersburg (Russian Federation); Power, J. G.; Gai, W. [Argonne National Laboratory, IL (United States)

2009-01-22

107

Beam Breakup Effects in Dielectric Based Accelerators  

NASA Astrophysics Data System (ADS)

The dynamics of the beam in structure-based wakefield accelerators leads to beam stability issues not ordinarily found in other machines. In particular, the high current drive beam in an efficient wakefield accelerator loses a large fraction of its energy in the decelerator structure, resulting in physical emittance growth, increased energy spread, and the possibility of head-tail instability for an off axis beam, all of which can lead to severe reduction of beam intensity. Beam breakup (BBU) effects resulting from parasitic wakefields provide a potentially serious limitation to the performance of dielectric structure based wakefield accelerators as well. We report on experimental and numerical investigation of BBU and its mitigation. The experimental program focuses on BBU measurements at the AWA facility in a number of high gradient and high transformer ratio wakefield devices. New pickup-based beam diagnostics will provide methods for studying parasitic wakefields that are currently unavailable. The numerical part of this research is based on a particle-Green's function beam breakup code we are developing that allows rapid, efficient simulation of beam breakup effects in advanced linear accelerators. The goal of this work is to be able to compare the results of detailed experimental measurements with the accurate numerical results and to design an external FODO channel for the control of the beam in the presence of strong transverse wakefields.

Schoessow, P.; Kanareykin, A.; Jing, C.; Kustov, A.; Altmark, A.; Power, J. G.; Gai, W.

2009-01-01

108

Sequential color breakup measured with induced saccades  

NASA Astrophysics Data System (ADS)

The commercial success of color sequential displays is limited by the fact that people perceive multiple color images during pursuit and saccadic eye movements. We conducted a psychophysical experiment to quantify visibility of these color artifacts for different saccadic speeds, display background brightness, and target size. An Infocus sequential-color projector was placed behind a projection screen to simulate a normal desktop display. Saccadic eye movements were induced by requiring subjects to recognize text targets displayed at two different screen locations in rapid succession. The speed of saccadic movements was varied by manipulating the distance between the two target locations. A white bar, either with or without a yellow and red color fringe on the right edge, was displayed as subjects moved their eyes for the text recognition task. The two versions of the white bar will not be distinguishable if color break-up is present, thus performance of this task can be used as a measure of color break-up. The visibility of sequential color breakup decreases with background intensity and size of the white target, and increases with saccadic speed.

Zhang, Xuemei; Farrell, Joyce E.

2003-06-01

109

Measurement of neutron response function for thin plastic scintillators using white neutron source from d D breakup reaction  

NASA Astrophysics Data System (ADS)

The neutron response function for thin plastic scintillators has been measured using the white neutron source produced by the d-D breakup reaction. Deuteron energies of 9, 12 and 14 MeV were chosen to produce the neutron energy range from 0.5 to 17 MeV. The intensity of the neutron beam was measured by a well-calibrated BC-501A liquid scintillation detector at 0?. The measured results were compared with Monte Carlo simulations and verified by additional experiments at a neutron generator and the 2×1.7 MV 5SDH-2 tandem accelerator. The results obtained from these experiments all agree well with the simulations.

Zhang, Guoguang; Ruan, Xichao; Li, Xia; Zhang, Jianfu; Song, Jiwen; Zhang, Xianpeng; Zhang, Xiaodong; Li, Dahai; Chen, Liang; Pan, Hongbo; Jiang, Jing; Zhong, Qiping; Huang, Hanxiong; Hou, Long; Zhou, Zuying

2007-12-01

110

A Study of Pseudo Breakup Events in the Aurora Using Polar/UVI  

NASA Astrophysics Data System (ADS)

We have analyzed pseudo breakup events in the aurora using 37 second LBHL Polar/UVI data during the months of November and December 2007 to study the relationship between breakups and pseudo breakups. Historically, the distinction between pseudo breakups, which expand locally, and normal breakups, which expand more globally, has been ill defined. We now present an explicit definition based on MLat expanse and peak auroral power. Often, the aurora will exhibit a series of pseudo breakup events before the commencement of a normal breakup. Sometimes a normal breakup does not occur. We analyze the properties of pseudo breakups and parameters that might make a normal breakup more or less likely to occur after a series of pseudo breakup events. There is no statistical difference in MLat location, peak area, peak power dissipation, and total energy deposition for individual pseudo breakups leading to a normal breakup and those that do not. A normal breakup is likely to occur only during the first 100 minutes of a sequence of pseudo breakups. Pseudo breakup sequences leading to a breakup are much shorter than those not leading to a breakup. However, distributions of total energy (in electron precipitation) for sequences leading and not leading to a normal breakup are the same. Although the physical implications of our results are complicated and unclear, pseudo breakup events should be incorporated in any magnetospheric substorm model.

Higgins, P. A.; Fillingim, M. O.; Parks, G. K.

2008-12-01

111

Incorporation of Aggregate Breakup in the Simulation of Orthokinetic Coagulation.  

PubMed

The agglomeration and breakup of floc aggregates formed in orthokinetic coagulation is examined. By considering local flow strain-rate, a breakup rate kernel is derived based on flow-induced normal stresses. The new breakup kernel is included in a population size class balance for floc aggregates. The resulting population balance was solved numerically over a wide range of parameters to obtain a variety of floc size distributions. Results indicate that the inclusion of a breakup kernel in orthokinetic coagulation modeling eliminates the computational growth to a maximum size class, producing more realistic distributions. The breakup kernel was rigorously compared to prior research and found to be consistent with the earlier theories of coagulation agglomeration and breakup. Copyright 1999 Academic Press. PMID:10395769

Kramer; Clark

1999-08-01

112

Bromine and iodine excitation-function measurements with protons and deuterons at 3--17 MeV  

SciTech Connect

We report nuclear excitation functions for the reactions [sup 79]Br[([ital p],[ital n])+([ital d],2[ital n])][sup 79]Kr, [sup 81]Br[([ital p],[ital n])+ ([ital d],2[ital n])][sup 81]Br, [sup 81]Br([ital d],[ital p])[sup 82]Br, and [sup 127]I[([ital p],[ital n])+([ital d],2[ital n])][sup 127]Xe. The measurements were made from reaction threshold to 17 MeV with the Lawrence Livermore National Laboratory's Tandem Van de Graaff accelerator using the stacked-foil method. The [sup 79]Br([ital d],2[ital n])[sup 79]Kr and the [sup 81]Br excitation functions are the first reported. The targets consisted of the halides dispersed in the plastic Kapton. The activated targets were assayed using [gamma] counting and mass spectrometry. We found that we had to remeasure the gamma intensities for the [sup 79]Kr decay. The excitation functions were modeled using the Hauser-Feshbach statistical-model code STAPRE, using the exciton preequilibrium model. We found a preference for the back-shifted (BS) level density prescription over the use of the Gilbert-Cameron prescription. For BS, the constant [ital K], governing the transition to equilibrium, was taken as 500 to 700 MeV[sup 3]. These values gave preequilibrium fractions consistent with those we obtained from ion-recoil range studies of light ion reactions. In general the modeling agreed well with experiment. For the deuteron induced reactions, we had to allow for deuteron breakup using a microscopic breakup fusion approach developed by Udagawa and Tamura. Our analysis of the stripping reaction, [sup 81]Br([ital d],[ital p])[sup 82]Br, by this procedure is especially noteworthy.

West, H.I. Jr.; Nuckolls, R.M.; Hudson, B.; Ruiz, B.; Lanier, R.G.; Mustafa, M.G. (University of California, Lawrence Livermore National Laboratory, Livermore, California 94551 (United States))

1993-01-01

113

Deuteron Dipole Polarizabilities and Sum Rules  

E-print Network

The scalar, vector, and tensor components of the (generalized) deuteron electric polarizability are calculated, as well as their logarithmic modifications. Several of these quantities arise in the treatment of the nuclear corrections to the deuterium Lamb shift and the deuterium hyperfine structure. A variety of second-generation potential models are used and a (subjective) error is assigned to the calculations. The zero-range approximation is used to analyze a subset of the results, and a simple relativistic version of this approximation is developed.

J. L. Friar; G. L. Payne

2005-03-16

114

Multipass Beam Breakup in Energy Recovery Linacs  

SciTech Connect

This paper is a compilation of several presentations on multipass beam breakup (BBU) in energy recovery linacs (ERL) given at the 32nd Advanced ICFA Beam Workshop on ERLs. The goal of this paper is to summarize the progress achieved in analytical, numerical, and experimental studies of the instability and outline available and proposed BBU mitigation techniques. In this paper, a simplified theory of multipass BBU in recirculating linacs is presented. Several BBU suppression techniques and their working principles are discussed. The paper presents an overview of available BBU codes. Results of experimental studies of multipass BBU at the Jefferson Laboratory (JLab) FEL Upgrade are described.

Eduard Pozdeyev; Christopher Tennant; Joseph Bisognano; M Sawamura; R. Hajima; T.I. Smith

2005-03-19

115

General design of the International Fusion Materials Irradiation Facility deuteron injector: Source and beam line  

SciTech Connect

In the framework of the International Fusion Materials Irradiation Facility-Engineering Validation and Engineering Design Activities (IFMIF-EVEDA) project, CEA/IRFU is in charge of the design and realization of the 140 mA cw deuteron Injector. The electron cyclotron resonance ion source operates at 2.45 GHz and a 4 electrode extraction system has been chosen. A 2 solenoid beam line, together with a high space charge compensation have been optimized for a proper beam injection in the 175 MHz radio frequency quadrupole. The injector will be tested with proton and deuteron beam production either in pulsed mode or in cw mode on the CEA-Saclay site before to be shipped to Japan. Special attention was paid to neutron emission due to (d,D) reaction. In this paper, the general IFMIF Injector design is reported, pointing out beam dynamics, radioprotection, diagnostics, and mechanical aspects.

Gobin, R.; Blideanu, V.; Bogard, D.; Bourdelle, G.; Chauvin, N.; Delferriere, O.; Girardot, P.; Jannin, J. L.; Langlois, S.; Loiseau, D.; Pottin, B.; Rousse, J.-Y.; Senee, F. [Commissariat a l'Energie Atomique, CEA/Saclay, DSM/IRFU, 91191 Gif/Yvette (France)

2010-02-15

116

General design of the International Fusion Materials Irradiation Facility deuteron injector: source and beam line.  

PubMed

In the framework of the International Fusion Materials Irradiation Facility-Engineering Validation and Engineering Design Activities (IFMIF-EVEDA) project, CEA/IRFU is in charge of the design and realization of the 140 mA cw deuteron Injector. The electron cyclotron resonance ion source operates at 2.45 GHz and a 4 electrode extraction system has been chosen. A 2 solenoid beam line, together with a high space charge compensation have been optimized for a proper beam injection in the 175 MHz radio frequency quadrupole. The injector will be tested with proton and deuteron beam production either in pulsed mode or in cw mode on the CEA-Saclay site before to be shipped to Japan. Special attention was paid to neutron emission due to (d,D) reaction. In this paper, the general IFMIF Injector design is reported, pointing out beam dynamics, radioprotection, diagnostics, and mechanical aspects. PMID:20192424

Gobin, R; Blideanu, V; Bogard, D; Bourdelle, G; Chauvin, N; Delferrière, O; Girardot, P; Jannin, J L; Langlois, S; Loiseau, D; Pottin, B; Rousse, J-Y; Senée, F

2010-02-01

117

Breakup of a droplet in a particulate shear flow  

Microsoft Academic Search

A numerical simulation using a Distributed-Lagrange-Multiplier-based computational method is conducted in order to simulate the breakup of a droplet in a particulate shear flow. The results show that the presence of particles strongly affects droplet deformation and may, in some cases, facilitate droplet breakup. In this problem, in addition to the capillary number and viscosity ratio, the particle volume fraction,

Arezoo Ardekani; Roger Rangel

2008-01-01

118

Modeling of Turbulence Effects on Liquid Jet Atomization and Breakup  

NASA Technical Reports Server (NTRS)

Recent experimental investigations and physical modeling studies have indicated that turbulence behaviors within a liquid jet have considerable effects on the atomization process. This study aims to model the turbulence effect in the atomization process of a cylindrical liquid jet. Two widely used models, the Kelvin-Helmholtz (KH) instability of Reitz (blob model) and the Taylor-Analogy-Breakup (TAB) secondary droplet breakup by O Rourke et al, are further extended to include turbulence effects. In the primary breakup model, the level of the turbulence effect on the liquid breakup depends on the characteristic scales and the initial flow conditions. For the secondary breakup, an additional turbulence force acted on parent drops is modeled and integrated into the TAB governing equation. The drop size formed from this breakup regime is estimated based on the energy balance before and after the breakup occurrence. This paper describes theoretical development of the current models, called "T-blob" and "T-TAB", for primary and secondary breakup respectivety. Several assessment studies are also presented in this paper.

Trinh, Huu P.; Chen, C. P.

2005-01-01

119

Surface wave transition before breakup on a laminar liquid jet  

Microsoft Academic Search

Problems of liquid jet breakup are very fundamental in the fluid-dynamics and application fields of atomization. Instability theories of the surface wave were usually used to describe the breakup phenomena. In these theories, it was assumed that the surface wave was a regular sinusoidal wave. However, irregular surface waves were frequently observed even though a liquid jet was laminar. In

M Arai; K Amagai

1999-01-01

120

Artificial satellite break-ups. I - Soviet ocean surveillance satellites  

Microsoft Academic Search

An analysis of the breakup patterns of eight Soviet Kosmos series ocean surveillance satellites is presented. It is noted that half of the 4700 objects presently detected in earth orbit are shards from destroyed objects. The locations and heading of each Soviet satellite breakup were tracked by the Naval Space Survelliance System. All events in the eastern hemisphere occurred in

N. L. Johnson

1983-01-01

121

Bag breakup of nonturbulent liquid jets in crossflow  

Microsoft Academic Search

An experimental investigation of the bag breakup of round nonturbulent liquid jets in gaseous crossflow at room temperature and pressure is described. Pulsed photography, pulsed shadowgraphy, and high-speed imaging were used to observe the column and surface waves along the liquid jet and the formation and breakup of bags. Measurements included: wavelengths of column and surface waves, jet velocities, the

C.-L. Ng; R. Sankarakrishnan; K. A. Sallam

2008-01-01

122

Polar lake circulation during ice break-up  

NASA Astrophysics Data System (ADS)

An extensive dataset on lake physical properties has been collected during the final stage of the ice-covered period in May-June 2013 in polar Lake Kilpisjärvi, Finland. The data reveal several important features of lake dynamics, which shed new light on the mechanism of ice cover break-up and ice melting in lakes and marginal seas. CTD transects with high spatial resolution showed up a 300m-wide upwelling zone in the center of the lake, driven by downslope converging flow of warm waters from open-water 'moat' along the lake shoreline. The resulting radial density gradient, balanced by the Coriolis force, created a lake-wide anti-cyclonically rotating gyre with a measured peak azimuthal velocity of 0.05 m/s. Appreciable marginal heating is driven in polar enclosed basins by high amount of solar radiation and by surface inflow of meltwater. Hence, quasi-geostrophic anticyclonic circulation is suggested to be a general feature of polar lakes, redistributing heat within a water body and potentially accelerating ice melting. In addition, high-resolution records of pressure, current velocities and water temperature revealed under-ice seiches with periods of 10 to 25 min. The ice breakup was associated with 10 times increase of seiche amplitudes under ice. The seiches decayed within 10-15 hours; during this short period, the previously ice-covered lake became ice-free. We suggest that seiche-driven vertical motions of the soft ice sheet contribute significantly to breaking and melting of seasonal ice in enclosed reservoirs.

Kirillin, Georgiy; Forrest, Alexander; Graves, Kelly; Laval, Bernard

2014-05-01

123

Deuteron Compton scattering below pion photoproduction threshold  

E-print Network

Deuteron Compton scattering below pion photoproduction threshold is considered in the framework of the nonrelativistic diagrammatic approach with the Bonn OBE potential. A complete gauge-invariant set of diagrams is taken into account which includes resonance diagrams without and with NN-rescattering and diagrams with one- and two-body seagulls. The seagull operators are analyzed in detail, and their relations with free- and bound-nucleon polarizabilities is discussed. It is found that both dipole and higher-order polarizabilities of the nucleon are needed for a quantitative description of recent experimental data. An estimate of the isospin-averaged dipole electromagnetic polarizabilities of the nucleon and the polarizabilities of the neutron is obtained from the data.

M. I. Levchuk; A. I. L'vov

1999-09-28

124

Deuteron Compton scattering below pion photoproduction threshold  

E-print Network

Deuteron Compton scattering below pion photoproduction threshold is considered in the framework of the nonrelativistic diagrammatic approach with the Bonn OBE potential. A complete gauge-invariant set of diagrams is taken into account which includes resonance diagrams without and with NN-rescattering and diagrams with one- and two-body seagulls. The seagull operators are analyzed in detail, and their relations with free- and bound-nucleon polarizabilities is discussed. It is found that both dipole and higher-order polarizabilities of the nucleon are needed for a quantitative description of recent experimental data. An estimate of the isospin-averaged dipole electromagnetic polarizabilities of the nucleon and the polarizabilities of the neutron is obtained from the data.

Levchuk, M I

2000-01-01

125

Intermediate energy proton-deuteron elastic scattering  

NASA Technical Reports Server (NTRS)

A fully symmetrized multiple scattering series is considered for the description of proton-deuteron elastic scattering. An off-shell continuation of the experimentally known twobody amplitudes that retains the exchange symmeteries required for the calculation is presented. The one boson exchange terms of the two body amplitudes are evaluated exactly in this off-shell prescription. The first two terms of the multiple scattering series are calculated explicitly whereas multiple scattering effects are obtained as minimum variance estimates from the 146-MeV data of Postma and Wilson. The multiple scattering corrections indeed consist of low order partial waves as suggested by Sloan based on model studies with separable interactions. The Hamada-Johnston wave function is shown consistent with the data for internucleon distances greater than about 0.84 fm.

Wilson, J. W.

1973-01-01

126

Helicity dependence in photodisintegration of the deuteron  

NASA Astrophysics Data System (ADS)

Weak nucleon-nucleon forces were parameterized with weak meson-nucleon coupling constants about 20 years ago [1]. The interaction can be studied through parity violation in deuteron photodisintegration [2]. The threshold region allow to measure the combinations of weak couplings hp and h? [3]. The progress in development high performance polarized electron source [4] allow to produce a record intensity of 70% circularly polarized beam of a few MeV photons (~1015 Hz). Almost 15 years after first attempt to measure PV in D(?,n)p [5] we had found that presently it is feasible to study of the process in energy range from threshold up to 8 MeV by using CEBAF injector. Expected neutron yield is of 1011-1012 Hz. The systematics of measurement will be checked by using Compton scattering from atomic electrons. .

Wojtsekhowski, Bogdan; van Oers, W. T. H.; DGNP Collaboration

2001-06-01

127

Capture of polarized deuterons on protons  

SciTech Connect

Full three-body calculations for the cross sections, vector analyzing powers, and tensor analyzing powers for radiative capture of polarized deuterons on protons over the energy range of available data are completed. The Paris, Bonn A, and AV14 two-nucleon interactions are used by means of separable-expansion methods. The Paris and Bonn interactions are handled by the Ernst-Shakin-Thaler (EST) method, whereas the AV14 potential is used through the new expansion of Koike, in order to reduce the two-variable integral equations to a single variable. The electromagnetic transition is calculated with the Siegert long-wavelength E1 operator. Comparisons are made between results for different nucleon-nucleon interactions and with respect to the experimental data. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

Fonseca, A.C. [Centro Fisica Nuclear da Universidade de Lisboa, Av. Prof. Gama Pinto, 2, P-1699 Lisbon (Portugal); Lehman, D.R. [Center for Nuclear Studies, Department of Physics, The George Washington University, Washington, DC 20052 (United States)

1995-05-10

128

Pion-less Effective Field Theory on Low-Energy Deuteron Electro-Disintegration  

E-print Network

In view of its relation to Big-Bang Nucleo-Synthesis and a reported discrepancy between nuclear models and data taken at S-DALINAC, electro-induced deuteron break-up 2H(e,e' p)n is studied at momentum transfer qelectric dipole currents and at NLO for magnetic ones converges order-by-order better than quantitatively predicted and contains no free parameter. It is at this order determined by simple, well-known observables. Decomposing the doubly differential cross-section into the longitudinal-plus-transverse (L+T), transverse-transverse (TT) and longitudinal-transverse interference (LT) terms, we find excellent agreement with the potential-model calculation by Arenh"ovel et al. Theory and data also agree well on \\sigma_{L+T}. There is however no space on the theory-side for the discrepancy of up to 30%, 3-\\sigma between theory and experiment in \\sigma_{LT}. From universality, we co...

Christlmeier, Stefan

2008-01-01

129

Surface-integral formalism of deuteron stripping  

NASA Astrophysics Data System (ADS)

The purpose of this paper is to develop an alternative theory of deuteron stripping to resonance states based on the surface-integral formalism of Kadyrov et al. [Ann. Phys. 324, 1516 (2009), 10.1016/j.aop.2009.02.003] and continuum-discretized coupled channels (CDCC). First we demonstrate how the surface-integral formalism works in the three-body model and then we consider a more realistic problem in which a composite structure of target nuclei is taken via optical potentials. We explore different choices of channel wave functions and transition operators and show that a conventional CDCC volume matrix element can be written in terms of a surface-integral matrix element, which is peripheral, and an auxiliary matrix element, which determines the contribution of the nuclear interior over the variable rnA. This auxiliary matrix element appears because of the inconsistency in treating of the n-A potential: This potential should be real in the final state to support bound states or resonance scattering and complex in the initial state to describe n-A scattering. Our main result is formulation of the theory of the stripping to resonance states using the prior form of the surface-integral formalism and CDCC method. It is demonstrated that the conventional CDCC volume matrix element coincides with the surface matrix element, which converges for the stripping to the resonance state. Also the surface representation (over the variable rnA) of the stripping matrix element enhances the peripheral part of the amplitude although the internal contribution does not disappear and increases with an increase of the deuteron energy. We present calculations corroborating our findings for both stripping to the bound state and the resonance.

Mukhamedzhanov, A. M.; Pang, D. Y.; Bertulani, C. A.; Kadyrov, A. S.

2014-09-01

130

Electroweak processes of the deuteron in effective field theory  

E-print Network

We review our recent calculations of electroweak processes involving the deuteron, based on pionless effective field theory with dibaryon fields. These calculations are concerned with neutron-neutron fusion and np -> d gamma at BBN energies.

Shung-ichi Ando

2005-09-23

131

Comment on breakup densities of hot nuclei  

NASA Astrophysics Data System (ADS)

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.

Viola, V. E.; Kwiatkowski, K.; Yennello, S. J.; Natowitz, J. B.

2006-06-01

132

Tensor Polarized Deuteron at an Electron-Ion Collider  

NASA Astrophysics Data System (ADS)

The deuteron is a simple, spin-1 nuclear system. This makes it an effective testbed for investigating nuclear physics. In addition, it is also relatively easy to polarize. Tensor polarization provides new opportunities to study properties of the nucleus. This is a significant part of the motivation for a polarized deuteron beam for an electron-ion collider envisioned for the future. This paper will discuss the motivation and a useful physics starting point for such a facility.

Kalantarians, N.

2014-10-01

133

Deuteron NN?(1440) components from a chiral quark model  

Microsoft Academic Search

We present a nonrelativistic coupled-channel calculation of the deuteron structure including ?? and NN?(1440) channels, besides the standard NN S and D-wave components. All the necessary building blocks to perform the calculation have been obtained from the same underlying quark model. The calculated NN?(1440) probabilities find support in the explanation given to different deuteron reactions. Since the discovery of nucleon

B. Julia-D ´ õaz; D. R. Entem; A. Valcarce; F. Fernandez

134

LEBU drag reduction in high Reynolds number boundary layers. [Large Eddy Break-Up  

NASA Technical Reports Server (NTRS)

Conventional and inverted, outer-layer leading-edge breakup devices (LEBUs) were water tunnel tested on an axisymmetric body over the Re number range from 380,000 to 3.8 million. Test results indicate a sharp degradation of the LEBUs' drag-reduction mechanism with increasing Re number. The most likely result of this degradation is a decoupling of the inner and outer scales at higher Re numbers; due to this decoupling, the breakup of the large structures by outer-layer devices has minimal influence on the near-wall, shear-producing scales. This suggests that smaller devices, closer to the walls, may be required for operation at elevated Re numbers.

Anders, J. B.

1989-01-01

135

Fusion, breakup and scattering of weakly bound nuclei  

NASA Astrophysics Data System (ADS)

We discuss the systematic results reached in the investigation of the breakup of weakly bound nuclei, at near barrier energies, and its effects on fusion cross sections, elastic scattering and reaction cross sections. Particularly we show that the complete fusion of weakly bound systems are suppressed by dynamic breakup effects at energies above the Coulomb barrier and enhanced at sub-barrier energies. We also show that the energy dependence of the optical potential obtained in the elastic scattering of weakly bound projectiles corresponds to the so-called Breakup Threshold Anomaly (BTA).

Gomes, P. R. S.; Lubian, J.

2014-09-01

136

17F breakup reactions: a touchstone for indirect measurements  

NASA Astrophysics Data System (ADS)

An exclusive study of 17F breakup reactions has been performed at the FRIBs facility of the Laboratori Nazionali del Sud in Catania (Italy). The experiment has been performed with the aim of testing the accuracy of the Coulomb-breakup indirect technique used to infer radiative-capture cross sections at low energies. This technique has been used in the 7Be(p,?)8B case, but has never been tested. By measuring the breakup of 17F into 16O+p, and comparing the inferred cross section for 16O(p,?)17F to direct precise measurements, the influence of E2 transitions and higher-order effects, that are predicted to be significant in Coulomb-breakup reactions, can be evaluated. The first results and preliminary model comparison are reported.

De Napoli, M.; Raciti, G.; Sfienti, C.; Capel, P.; Baye, D.; Giacoppo, F.; Rapisarda, E.; Cardella, G.; Descouvemont, P.; Mazzocchi, C.; Sparenberg, J.-M.

2011-10-01

137

{sup 17}F breakup reactions: a touchstone for indirect measurements  

SciTech Connect

An exclusive study of {sup 17}F breakup reactions has been performed at the FRIBs facility of the Laboratori Nazionali del Sud in Catania (Italy). The experiment has been performed with the aim of testing the accuracy of the Coulomb-breakup indirect technique used to infer radiative-capture cross sections at low energies. This technique has been used in the {sup 7}Be(p,{gamma}){sup 8}B case, but has never been tested. By measuring the breakup of {sup 17}F into {sup 16}O+p, and comparing the inferred cross section for {sup 16}O(p,{gamma}){sup 17}F to direct precise measurements, the influence of E2 transitions and higher-order effects, that are predicted to be significant in Coulomb-breakup reactions, can be evaluated. The first results and preliminary model comparison are reported.

De Napoli, M. [INFN-Laboratori Nazionali del Sud, I-95123 Catania (Italy); Raciti, G.; Sfienti, C. [Dipartimento di Fisica e Astronomia, Universita di Catania, I-95123, Catania (Italy); INFN-Sezione di Catania, I-95123, Catania (Italy); Capel, P. [National Superconducting Cyclotron Laboratory, MSU, East Lansing, MI 48824-1321 (United States); Baye, D.; Descouvemont, P.; Sparenberg, J.-M. [Physique Quantique et Nucleaire (CP 229) ULB, B-1050 Brussels (Belgium); Giacoppo, F. [INFN-Laboratori Nazionali del Sud, I-95123 Catania (Italy); Dipartimento di Fisica, Universita di Messina, I-98166 Messina (Italy); Rapisarda, E. [INFN-Sezione di Catania, I-95123, Catania (Italy); Centro Siciliano di Fisica Nucleare e Struttura della Materia, I-95125 Catania (Italy); Cardella, G. [INFN-Sezione di Catania, I-95123, Catania (Italy); Mazzocchi, C. [INFN-Sezione di Milano and Universita di Milano, I-20133, Milano (Italy)

2011-10-28

138

ISS Update: ATV-3 ReEntry Breakup Recorder  

NASA Video Gallery

ISS Update Commentator Pat Ryan talks with Dr. William Ailor, Principal Investigator for the ReEntry Breakup Recorder (REBR) for The Aerospace Corporation. Ailor talks about capturing data as Europ...

139

Breakup and coalescence characteristics of a hollow cone swirling spray  

NASA Astrophysics Data System (ADS)

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.

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

2012-12-01

140

A review of Wilson Cycle plate margins: What is the role of mantle plumes in continental break-up along former sutures?  

NASA Astrophysics Data System (ADS)

It was Tuzo Wilson (1966) who recognised that the different faunal distributions on both sides of the present-day North Atlantic Ocean required the existence of an earlier proto-Atlantic Ocean. The observation that the present-day Atlantic Ocean mainly opened along a former suture was a crucial step in the formulation of the Wilson Cycle theory. The theory implies that collision zones are structures that are able to localize extensional deformation for long times after the collision has waned. We review margin pairs around the Atlantic and Indian Oceans with the aim to evaluate the extent to which oceanic opening used former sutures and to analyse the role of mantle plumes in continental break-up. We aid our analyses with plate tectonic reconstructions using GPlates (www.gplates.org). Already Wilson recognized that Atlantic break-up did not always follow the precise line of previous junction. For example, Atlantic opening did not utilize the Iapetus suture in Great Britain and rather than opening along the younger Rheic suture north of Florida, break-up occurred along the older Pan-African structures south of Florida. As others before us, we find no correlation of suture and break-up age. Often continental break-up occurs some hundreds of Myrs after collision, but it may also take more than a Gyr, as for example for Australia-Antarctica and Congo-São Francisco. This places serious constraints on potential collision zone weakening mechanisms. Several studies have pointed to a link between continental break-up and large-scale mantle upwellings. It is, however, much debated whether plumes use existing rifts as a pathway, or whether plumes play an active role in causing rifting. It is also important to realise that in several cases break-up cannot be related to plume activity. Examples are the Iberia-Newfoundland, Equatorial Atlantic Ocean, and Australia-Antarctica plate margins. For margins that are associated with large igneous provinces (LIPs), we find a positive correlation between break-up age and LIP age. We interpret this to indicate that plumes can aid the factual continental break-up. However, plumes may have been guided towards the rift for margins that experienced a long rift history (e.g., Norway-Greenland), to then trigger the break-up. This could offer a partial reconciliation in the debate of a passive or active role for mantle plumes in continental break-up. (Wilson, J.T., 1966. Did the Atlantic close and then re-open? Nature 211, 676-681)

Buiter, Susanne; Torsvik, Trond

2013-04-01

141

A new model for auroral breakup during substorms  

SciTech Connect

A model for substorm breakup is developed, based on the relaxation of stretched (closed) dipolar field lines, and the formation of an incipient current wedge within a single arc structure. It is argued that the establishment of a coupled current structure within a single arc leads to a quasi-stable system; i.e., the pre-breakup regime. Perturbation of the pre-breakup structure leads to an instability criterion. It is found, consistent with observations, that narrower auroral arcs at lower L shells undergo the most explosive poleward expansion. According to this model, the precise location at which breakup occurs depends on the O/sup +/ density in the plasma sheet, the level of magnetic activity (K/sub p/), and the intensity of the substorm westward electrojet in the ionosphere. An enhancement of any of these features will cause breakup to occur at lower L shells. Comparison of our model with the Heppner-Maynard polar-cap potential model indicates that breakup is restricted to the west of the Harang discontinuity consistent with recent observations from the Viking satellite.

Rothwell, P.L.; Block, L.P.; Falthammar, C.G.; Silevitch, M.B.

1989-04-01

142

Deuteron injector for Peking University Neutron Imaging Facility project.  

PubMed

The deuteron injector developed for the PKUNIFTY (Peking University Neutron Imaging Facility) has been installed and commissioned at Peking University (PKU). The injector system must transfer 50 keV 50 mA of D(+) ion beam to the entrance of the 2 MeV radio frequency quadrupole (RFQ) with 10% duty factor (1 ms, 100 Hz). A compact 2.45 GHz permanent magnet electron cyclotron resonance (PMECR) ion source and a 1.36 m long low energy beam transport (LEBT) line using two solenoids was developed as the deuteron injector. A ?5 mm four-quadrant diaphragm was used to simulate the entrance of RFQ electrodes. The beam parameters are measured after this core with an emittance measurement unit (EMU) and a bending magnet for ion fraction analysis at the end of injector. During the commissioning, 77 mA of total deuteron beam was extracted from PMECR and 56 mA of pure D(+) beam that passed through the ?5 mm four-quadrant diaphragm was obtained at the position of RFQ entrance with the measured normalized rms emittance 0.12-0.16??mm?mrad. Ion species analysis results show that the deuteron fraction is as high as 99.5%. All of the parameters satisfy PKUNIFTY's requirements. In this paper, we will describe the deuteron injector design and report the commissioning results as well as the initial operation. PMID:22380316

Ren, H T; Peng, S X; Lu, P N; Zhou, Q F; Yuan, Z X; Zhao, J; Zhang, M; Song, Z Z; Yu, J X; Guo, Z Y; Chen, J E

2012-02-01

143

Deuteron injector for Peking University Neutron Imaging Facility projecta)  

NASA Astrophysics Data System (ADS)

The deuteron injector developed for the PKUNIFTY (Peking University Neutron Imaging Facility) has been installed and commissioned at Peking University (PKU). The injector system must transfer 50 keV 50 mA of D+ ion beam to the entrance of the 2 MeV radio frequency quadrupole (RFQ) with 10% duty factor (1 ms, 100 Hz). A compact 2.45 GHz permanent magnet electron cyclotron resonance (PMECR) ion source and a 1.36 m long low energy beam transport (LEBT) line using two solenoids was developed as the deuteron injector. A ?5 mm four-quadrant diaphragm was used to simulate the entrance of RFQ electrodes. The beam parameters are measured after this core with an emittance measurement unit (EMU) and a bending magnet for ion fraction analysis at the end of injector. During the commissioning, 77 mA of total deuteron beam was extracted from PMECR and 56 mA of pure D+ beam that passed through the ?5 mm four-quadrant diaphragm was obtained at the position of RFQ entrance with the measured normalized rms emittance 0.12-0.16? mm mrad. Ion species analysis results show that the deuteron fraction is as high as 99.5%. All of the parameters satisfy PKUNIFTY's requirements. In this paper, we will describe the deuteron injector design and report the commissioning results as well as the initial operation.

Ren, H. T.; Peng, S. X.; Lu, P. N.; Zhou, Q. F.; Yuan, Z. X.; Zhao, J.; Zhang, M.; Song, Z. Z.; Yu, J. X.; Guo, Z. Y.; Chen, J. E.

2012-02-01

144

Deuteron injector for Peking University Neutron Imaging Facility project  

SciTech Connect

The deuteron injector developed for the PKUNIFTY (Peking University Neutron Imaging Facility) has been installed and commissioned at Peking University (PKU). The injector system must transfer 50 keV 50 mA of D{sup +} ion beam to the entrance of the 2 MeV radio frequency quadrupole (RFQ) with 10% duty factor (1 ms, 100 Hz). A compact 2.45 GHz permanent magnet electron cyclotron resonance (PMECR) ion source and a 1.36 m long low energy beam transport (LEBT) line using two solenoids was developed as the deuteron injector. A {phi}5 mm four-quadrant diaphragm was used to simulate the entrance of RFQ electrodes. The beam parameters are measured after this core with an emittance measurement unit (EMU) and a bending magnet for ion fraction analysis at the end of injector. During the commissioning, 77 mA of total deuteron beam was extracted from PMECR and 56 mA of pure D{sup +} beam that passed through the {phi}5 mm four-quadrant diaphragm was obtained at the position of RFQ entrance with the measured normalized rms emittance 0.12-0.16{pi} mm mrad. Ion species analysis results show that the deuteron fraction is as high as 99.5%. All of the parameters satisfy PKUNIFTY's requirements. In this paper, we will describe the deuteron injector design and report the commissioning results as well as the initial operation.

Ren, H. T.; Chen, J. E. [Graduate University of Chinese Academy of Sciences, Beijing 100049 (China); SKLNPT, Institute of Heavy Ion Physics, Peking University, Beijing 100871 (China); Peng, S. X.; Lu, P. N.; Zhou, Q. F.; Yuan, Z. X.; Zhao, J.; Zhang, M.; Song, Z. Z.; Yu, J. X.; Guo, Z. Y. [SKLNPT, Institute of Heavy Ion Physics, Peking University, Beijing 100871 (China)

2012-02-15

145

Modeling of Turbulence Effects on Liquid Jet Atomization and Breakup  

NASA Technical Reports Server (NTRS)

Recent experimental investigations and physical modeling studies have indicated that turbulence behaviors within a liquid jet have considerable effects on the atomization process. For certain flow regimes, it has been observed that the liquid jet surface is highly turbulent. This turbulence characteristic plays a key role on the breakup of the liquid jet near to the injector exit. Other experiments also showed that the breakup length of the liquid core is sharply shortened as the liquid jet is changed from the laminar to the turbulent flow conditions. In the numerical and physical modeling arena, most of commonly used atomization models do not include the turbulence effect. Limited attempts have been made in modeling the turbulence phenomena on the liquid jet disintegration. The subject correlation and models treat the turbulence either as an only source or a primary driver in the breakup process. This study aims to model the turbulence effect in the atomization process of a cylindrical liquid jet. In the course of this study, two widely used models, Reitz's primary atomization (blob) and Taylor-Analogy-Break (TAB) secondary droplet breakup by O Rourke et al. are examined. Additional terms are derived and implemented appropriately into these two models to account for the turbulence effect on the atomization process. Since this enhancement effort is based on a framework of the two existing atomization models, it is appropriate to denote the two present models as T-blob and T-TAB for the primary and secondary atomization predictions, respectively. In the primary breakup model, the level of the turbulence effect on the liquid breakup depends on the characteristic time scales and the initial flow conditions. This treatment offers a balance of contributions of individual physical phenomena on the liquid breakup process. For the secondary breakup, an addition turbulence force acted on parent drops is modeled and integrated into the TAB governing equation. The drop size formed from this breakup regime is estimated based on the energy balance before and after the breakup occurrence. The turbulence energy is also considered in this process.

Trinh, Huu; Chen, C. P.

2004-01-01

146

Deuteron electromagnetic form factors in a renormalizable formulation of chiral effective field theory  

E-print Network

We calculate the deuteron electromagnetic form factors in a modified version of Weinberg's chiral effective field theory approach to the two-nucleon system. We derive renormalizable integral equations for the deuteron without partial wave decomposition. Deuteron form factors are extracted by applying the Lehmann-Symanzik-Zimmermann reduction formalism to the three-point correlation function of deuteron interpolating fields and the electromagnetic current operator. Numerical results of a leading-order calculation with removed cutoff regularization agree well with experimental data.

E. Epelbaum; A. M. Gasparyan; J. Gegelia; M. R. Schindler

2013-11-27

147

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

E-print Network

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.

Kazuki Yoshida; Tokuro Fukui; Kosho Minomo; Kazuyuki Ogata

2013-12-27

148

Inclusive and Exclusive Scatterings from Tensor Polarized Deuteron  

NASA Astrophysics Data System (ADS)

The possibility of using a tensor polarized deuteron target in electroproduction reactions creates new opportunities for studying different phenomena related to the short-range hadronic and nuclear physics. The use of the tensor polarized deuteron allows us to isolate smaller than average inter-nucleon distances for the bound two-nucleon system. In this report we consider several high Q2 reactions which are particularly sensitive to the short-range two- nucleon configurations in the deuteron. One is the relativistic dynamics of electron-bound- nucleon scattering, which can be studied in both inclusive and exclusive reactions, and the other is the strong final state interaction in close proximity of two nucleons that can be used as a sensitive probe for color-transparency phenomena.

Sargsian, M. M.; Strikman, M. I.

2014-10-01

149

Coulomb Effect in Nucleon-Deuteron Elastic Scattering  

NASA Astrophysics Data System (ADS)

We have applied the quark-model nucleon-nucleon interaction fss2 to the nucleon-deuteron scattering. The screened cutoff Coulomb force in the momentum space has been incorporated to the proton-deuteron scattering by extending the matching condition, which is proposed by Vincent and Phatak for the sharply cutoff Coulomb problem. The model fss2 can reproduce the overall characteristics of the experimental data. It is found that fss2 partially incorporates the attractive feature, which accords with the good reproduction of the triton binding energy and neutron-deuteron doublet scattering length. This attractive feature is due to the off-shell effect related to the quark-model description of the short-range repulsion of the two-nucleon force.

Fukukawa, K.; Fujiwara, Y.

2013-08-01

150

Large Q{sup 2} electrodisintegration of the deuteron  

SciTech Connect

The break up of the deuteron is studied at high Q{sup 2} kinematics, with main motivation to probe the deuteron at small internucleon distances. For this, two main issues are studied: electromagnetic interaction of the virtual photon with the bound nucleon and the strong interactions of the produced baryons in the final state of the reaction. Within virtual nucleon approximation we developed a new prescription to account for the bound nucleon effects in the electromagnetic interaction. The final state interaction at high Q{sup 2} kinematics is calculated within generalized eikonal approximation (GEA). Comparison with the first experimental data confirm GEA's early prediction that the rescattering is maximal at {approx}70 deg. of recoil nucleon production relative to the momentum of the virtual photon. Also the forward recoil nucleon angles are best suited for studies of the deuteron at small distances.

Sargsian, Misak M. [Department of Physics, Florida International University, Miami, FL 33199 (United States)

2011-10-24

151

Inclusive and Exclusive Scatterings from Tensor Polarized Deuteron  

E-print Network

The possibility of using a tensor polarized deuteron target in electroproduction reactions creates new opportunities for studying different phenomena related to the short-range hadronic and nuclear physics. The use of tensor polarized deuteron allows to isolate smaller than average inter-nucleon distances for the bound two-nucleon system. In this report we consider several of high $Q^2$ reactions which are particularly sensitive to the short-range two-nucleon configurations in the deuteron. The one is the relativistic dynamics of electron-bound-nucleon scattering which can be studied in both inclusive and exclusive reactions, other is the strong final state interaction in close proximity of two nucleons that can be used as a sensitive probe for color-transparency phenomena.

Misak M. Sargsian; Mark I. Strikman

2014-09-22

152

Inclusive and Exclusive Scatterings from Tensor Polarized Deuteron  

E-print Network

The possibility of using a tensor polarized deuteron target in electroproduction reactions creates new opportunities for studying different phenomena related to the short-range hadronic and nuclear physics. The use of tensor polarized deuteron allows to isolate smaller than average inter-nucleon distances for the bound two-nucleon system. In this report we consider several of high $Q^2$ reactions which are particularly sensitive to the short-range two-nucleon configurations in the deuteron. The one is the relativistic dynamics of electron-bound-nucleon scattering which can be studied in both inclusive and exclusive reactions, other is the strong final state interaction in close proximity of two nucleons that can be used as a sensitive probe for color-transparency phenomena.

Sargsian, Misak M

2014-01-01

153

Deuteron photodisintegration with polarized photons at astrophysical energies  

NASA Astrophysics Data System (ADS)

Following precise experimental studies at the Duke Free-Electron Laser Laboratory, we discuss the photodisintegration of deuterons with 100% linearly polarized photons using a model independent theoretical approach taking together M1 and E1 amplitudes simultaneously. The isoscalar M1s contribution is also taken exactly into account. From the existing experimental measurement on doubly polarized thermal neutron capture, it is seen that the isoscalar M1s contribution could be of the same order of magnitude as the experimentally measured cross sections at energies relevant to Big Bang Nucleosynthesis (BBN). Therefore appropriate measurements on deuteron photodisintegration are suggested to empirically determine the M1s contribution at astrophysical energies.

Ramachandran, G.; Shilpashree, S. P.

2006-11-01

154

P and T violating form factors of the deuteron.  

PubMed

We calculate the electric-dipole and magnetic-quadrupole form factors of the deuteron that arise as a low-energy manifestation of parity and time-reversal violation in quark-gluon interactions. We consider the QCD vacuum angle and the dimension-six operators that originate from physics beyond the standard model: the quark electric and chromoelectric dipole moments and the gluon chromoelectric dipole moment. Within the framework of two-flavor chiral perturbation theory, we show that in combination with the nucleon electric dipole moment, the deuteron moments would allow an identification of the dominant source(s) of symmetry violation. PMID:21929227

de Vries, J; Mereghetti, E; Timmermans, R G E; van Kolck, U

2011-08-26

155

Effects of large mass transfer and statistical decay on ternary breakup in the reaction U238+Au197 at 15A MeV  

NASA Astrophysics Data System (ADS)

The ternary breakup mechanism of U238+Au197 at 15A MeV has been investigated by a hybrid model that combines the improved quantum molecular dynamics (ImQMD) model together with a statistical code gemini++. The results are in good agreement with the experimental data and indicate that in peripheral reactions, ternary breakup in this reaction results from quasi-U statistical fission while for central and semicentral collisions it can be understood by a two-step mechanism: deep-inelastic collision (DIC) followed by a sequential binary breakup of one of the DIC products. In the process of DIC, there is a large mass transfer from Au to U to form transuranium. Due to the low fission barrier, such transuranium nuclei will decay into stable light nuclei through various fission modes. An event-by-event analysis shows that the second breakup mainly occurs in the deexcitation process and most of the ternary breakup events are from semicentral and peripheral collisions that correspond to deep inelastic and quasi-elastic reactions, respectively.

Jiang, Xiang; Yan, Shiwei

2014-08-01

156

Reaction-dependent spin population and evidence of breakup in {sup 18}O  

SciTech Connect

Angular distributions and angular correlations have been measured for the emission of one and two {alpha}-particles in the {sup 18}O+{sup 207,208}Pb,{sup 209}Bi reactions at several beam energies above the Coulomb barrier. The results rule out fusion evaporation as the main reaction mechanism for the channels involving {alpha}-particle emission and support the interpretation of the breakup of the {sup 18}O projectiles into at least {sup 14}C+{alpha} and {sup 10}Be+{sup 8}Be before fusion.

Hojman, D.; Pacheco, A.J.; Testoni, J.E.; Davidson, J.; Davidson, M. [Departamento de Fisica, Comision Nacional de Energia Atomica, 1429 Buenos Aires (Argentina); CONICET, 1033 Buenos Aires (Argentina); Cardona, M.A.; Fernandez-Niello, J.O.; Kreiner, A.J. [Departamento de Fisica, Comision Nacional de Energia Atomica, 1429 Buenos Aires (Argentina); CONICET, 1033 Buenos Aires (Argentina); Escuela de Ciencia y Tecnologia, Universidad de San Martin, 1650 San Martin (Argentina); Arazi, A.; Capurro, O.A.; Marti, G.V. [Departamento de Fisica, Comision Nacional de Energia Atomica, 1429 Buenos Aires (Argentina); Bazzacco, D.; Lenzi, S.M.; Lunardi, S.; Alvarez, C. Rossi; Ur, C. [Dipartimento di Fisica and INFN, I-35131 Padova (Italy); Burlon, A.; Debray, M.E. [Departamento de Fisica, Comision Nacional de Energia Atomica, 1429 Buenos Aires (Argentina); Escuela de Ciencia y Tecnologia, Universidad de San Martin, 1650 San Martin (Argentina); De Angelis, G.; De Poli, M. [INFN, Laboratori Nazionali di Legnaro, I-35020 Legnaro (Italy)] (and others)

2006-04-15

157

Scaling laws for near-barrier Coulomb and nuclear breakup  

NASA Astrophysics Data System (ADS)

We investigate the nuclear and the Coulomb contributions to the breakup cross sections of 6Li in collisions with targets in different mass ranges. Comparing cross sections for different targets at collision energies corresponding to the same E/VB, we obtain interesting scaling laws. First, we derive an approximate linear expression for the nuclear breakup cross section as a function of AT1/3. We then confirm the validity of this expression performing continuum-discretized coupled-channels (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.

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

2013-10-01

158

Break-up stage restoration in multifragmentation reactions  

E-print Network

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 $^3$He is consistent with break-up genesis of this isotope.

Raduta, Ad R; Borderie, B; Neindre, N Le; Piantelli, S; Rivet, M F

2007-01-01

159

Time reversal invariance violation in neutron-deuteron scattering  

NASA Astrophysics Data System (ADS)

Time reversal invariance-violating (TRIV) effects in low-energy elastic neutron-deuteron scattering are calculated using meson exchange and EFT-type TRIV potentials in a distorted-wave Born approximation with realistic hadronic strong interaction wave functions, obtained by solving the three-body Faddeev equations in configuration space. The relation between TRIV and parity-violating observables is discussed.

Song, Young-Ho; Lazauskas, Rimantas; Gudkov, Vladimir

2011-06-01

160

Time Reversal Invariance Violation in Neutron Deuteron Scattering  

E-print Network

Time reversal invariance violating (TRIV) effects for low energy elastic neutron deuteron scattering are calculated for meson exchange and EFT-type of TRIV potentials in a Distorted Wave Born Approximation, using realistic hadronic strong interaction wave functions, obtained by solving three-body Faddeev equations in configuration space. The relation between TRIV and parity violating observables are discussed.

Song, Young-Ho; Gudkov, Vladimir

2011-01-01

161

Time reversal invariance violation in neutron-deuteron scattering  

Microsoft Academic Search

Time reversal invariance-violating (TRIV) effects in low-energy elastic neutron-deuteron scattering are calculated using meson exchange and EFT-type TRIV potentials in a distorted-wave Born approximation with realistic hadronic strong interaction wave functions, obtained by solving the three-body Faddeev equations in configuration space. The relation between TRIV and parity-violating observables is discussed.

Young-Ho Song; Rimantas Lazauskas; Vladimir Gudkov

2011-01-01

162

Time Reversal Invariance Violation in Neutron Deuteron Scattering  

E-print Network

Time reversal invariance violating (TRIV) effects for low energy elastic neutron deuteron scattering are calculated for meson exchange and EFT-type of TRIV potentials in a Distorted Wave Born Approximation, using realistic hadronic strong interaction wave functions, obtained by solving three-body Faddeev equations in configuration space. The relation between TRIV and parity violating observables are discussed.

Young-Ho Song; Rimantas Lazauskas; Vladimir Gudkov

2011-04-15

163

JLAB Measurements of the Deuteron Electric and Magnetic Form Factors  

SciTech Connect

Large-momentum transfer JLab measurements of the deuteron electric and magnetic form factors are reported. The data are compared to theoretical models based on the relativistic impulse approximation with the inclusion of meson-exchange currents, and to predictions of quark-dimensional scaling and perturbative QCD.

Gerassimos G. Petratos

2000-12-12

164

Neutron-deuteron elastic scattering and three-nucleon force  

E-print Network

The differential cross section for neutron-deuteron elastic scattering was measured at six angles over the center-of-mass angular range 65? - 1300? and incident neutron energies 140 - 240 MeV at the LANSCE/WNR facility of ...

Chtangeev, Maxim B

2005-01-01

165

Contraction of the deuteron cluster in 6Li  

NASA Astrophysics Data System (ADS)

The dependence of the rms radius of the deuteron cluster in 6Li on the relative d-? momentum was investigated on the basis of the three-body wave function given by Rai, Lehman, and Ghovanlou. NUCLEAR STRUCTURE p-n relative wave function, cluster contraction.

Végh, L.; Erö, J.

1981-05-01

166

APPLICATIONS OF MEV PROTON AND DEUTERON LINEAR ACCELERATORS  

Microsoft Academic Search

There are a number of applications, either proposed, cur- rently under development or already reduced to practice, that utilize proton or deuteron beams in the 1-10 MeV energy regime. These applications have been reviewed and the accel- erator requirements summarized. In terms of the beam time- structure, nearly all of the applications fall into three broad categories. (1) Beams that

George H. Gillespie; Gerald E. McMichael

1996-01-01

167

Spin Structure Moments of the Proton and Deuteron  

SciTech Connect

Moments of the spin structure functions g1 and g2 of the proton and deuteron have been measured in the resonance region at intermediate four momentum transfer. We perform a Nachtmann moment analysis of this data, along with isovector and isoscalar combinations, in order to rigorously account for target mass effects. This analysis provides the first definitive evidence for dynamic higher twists.

Slifer, Karl; Rondon-Aramayo, Oscar; Aghalaryan, Aram; Ahmidouch, Abdellah; Asaturyan, Razmik; Bloch, Frederic; Boeglin, Werner; Bosted, Peter; Carasco, Cedric; Carlini, Roger; Cha, Jinseok; Chen, Jian-Ping; Christy, Michael; Cole, Leon; Coman, Luminita; Crabb, Donald; Danagoulian, Samuel; Day, Donal; Dunne, James; Elaasar, Mostafa; Ent, Rolf; Fenker, Howard; Frlez, Emil; Gaskell, David; Gan, Liping; Gomez, Javier; Hu, Bitao; Jourdan, Juerg; Jones, Mark; Keith, Christopher; Keppel, Cynthia; Khandaker, Mahbubul; Klein, Andreas; Kramer, Laird; Liang, Yongguang; Lichtenstadt, Jechiel; Lindgren, Richard; Mack, David; McKee, Paul; McNulty, Dustin; Meekins, David; Mkrtchyan, Hamlet; Nasseripour, Rakhsha; Niculescu, Maria-Ioana; Normand, Kristoff; Norum, Blaine; Pocanic, Dinko; Prok, Yelena; Raue, Brian; Reinhold, Joerg; Roche, Julie; Rohe, Daniela; Savvinov, Nikolai; Sawatzky, Bradley; Seely, Mikell; Sick, Ingo; Smith, C.; Smith, G.; Stepanyan, Samuel; Tang, Liguang; Tajima, Shigeyuki; Testa, Giuseppe; Vulcan, William; Wang, Kebin; Warren, G.; Wesselmann, Frank; Wood, Stephen; Yan, Chen; Yuan, Lulin; Yun, Junho; Zeier, Markus; Guo Zhu, Hong

2009-01-01

168

Two-photon exchange effect on deuteron electromagnetic form factors  

E-print Network

Corrections of two-photon exchange to proton and neutron electromagnetic form factors are employed to study the effect of two-photon exchange on the deuteron electromagnetic form factors. Numerical results of the effect are given. It is suggested to test the effect in the measurement of $P_z$ in a small angle limit.

Yu Bing Dong; D. Y. Chen

2009-05-09

169

Elliptic flow of deuterons in relativistic heavy-ion collisions  

E-print Network

Using a dynamical model based on the NN -> d pi,NNN -> dN, and NN pi -> d pi reactions and measured proton and pion transverse momentum spectra and elliptic flows, we study the production of deuterons and their elliptic flow in heavy-ion collisions...

Oh, Yongseok; Ko, Che Ming.

2007-01-01

170

PATHOLOGIC AND BEHAVIORAL CHANGES IN MICE FOLLOWING CNS DEUTERON IRRADIATION  

Microsoft Academic Search

Radiogenic lesions were produced in mice by 1 mm focal deuteron beams at ; a dose of 8,000 rads directed unilaterally and bilaterally to the parietal areas ; and unilaterally to the cerebellum, and by two 9 x 0.025 mm microbeams, 0.5 mm ; apart, applied across the neocerebellar cortex at 72,000 rads. These ; histopathologically demonstrable alterations were related

J. M. Ordy; H. W. Barnes; T. Samorajski; H. J. Curtis; L. Wolin; W. Zeman

1962-01-01

171

Deuteron production and elliptic flow in relativistic heavy ion collisions  

E-print Network

The hadronic transport model ART is extended to include the production and annihilation of deuterons via the reactions BB dM, where B and M stand for baryons and mesons, respectively, as well as their elastic scattering with mesons and baryons...

Oh, Yongseok; Lin, Zi-Wei; Ko, Che Ming.

2009-01-01

172

Investigation of deuteron induced nuclear reactions on niobium  

NASA Astrophysics Data System (ADS)

Monoisotopic natural niobium foils were irradiated with 10 MeV deuteron beam in the Debrecen Cyclotron Laboratory by using the well-established stacked-foil technique. The experimental cross-sections of the deuteron induced nuclear reactions on natural Nb were determined as a part of our systematic study on excitation functions for isotope production, industrial and other applications. A stack of high-purity niobium foils (7.5 ?m thick, 13 pieces) was irradiated. The stack was constructed so that it covered the whole energy range from the threshold energy to the maximum bombarding energy. Catcher foils (aluminum, 9 ?m) were also used to separate the target foils and to extend the energy degradation. A Ti foil (13.6 ?m) at the front was also applied to monitor the beam current. The possible reactions were listed and the earlier data were collected from the literature. Because of the irradiation and measurement technique only the isotopes with half-life greater than 10 min could be seen. To avoid the activity-loss because of the recoil of the produced isotopes from the backside of the Nb foils, the Nb foils were measured in the first step together with the next Al foil. After that, the Nb and/or Al foils were measured separately. So not only the cross-section, but also the implantation yield of the reactions could be determined. From practical point of view one of the most important isotope from the deuteron induced reactions on natural Nb is the 93mMo ( T 1/2=6.85 h), and practically it is the only isotope measurable under 10 MeV deuteron energy. No earlier measured cross-section data were found in the literature. Systematic study was made to avoid interference from other reactions and from neutron activation, which can occur by deuteron splitting.

Ditrói, F.; Tárkányi, F.; Ali, M. A.

2000-03-01

173

Commissioning and operation of the deuteron injector for PKUNIFTY project.  

PubMed

PKUNIFTY (PeKing University Neutron Imaging FaciliTY), a thermal neutron imaging facility based on a 2 MeV RFQ accelerator, has been constructed at Peking University. Its deuteron injector, which consists of a 2.45 GHz permanent magnet electron cyclotron resonance (PMECR) deuteron ion source and a two-solenoid low energy beam transport (LEBT), aims at producing and delivering 50 mA, 50 keV deuteron beam with a duty factor of 10% (1 ms, 100 Hz). In the preliminary tests of RFQ accelerator, the ECR ion source and LEBT are required to operate at various duty factors (from 1% to 10%). The deuteron ion source has been tested with different pulse widths for this reason. In order to optimize the transmission parameters, the beam current at the exit of RFQ as a function of solenoids tuning and steering magnets tuning are carefully studied. The beam emittance at the entrance of RFQ has been measured with space charge compensation by different argon gas (RG) pressure from 1.6 × 10(-4) Pa to 4.7 × 10(-3) Pa. The measuring results show the best compensating pressure is 3.5 × 10(-3) Pa with a minimal normalized rms emittance of 0.12 pi?mm?mrad. During the commissioning, we found the purity of deuteron gas is an important factor which severely affects ECR discharge and plasma intensity inside the ion source chamber. The detailed experimental results obtained during the commissioning are discussed in this paper. PMID:24593440

Ren, H T; Peng, S X; Lu, P N; Zhao, J; Zhou, Q F; Song, Z Z; Yuan, Z X; Yu, J X; Guo, Z Y; Chen, J E

2014-02-01

174

Commissioning and operation of the deuteron injector for PKUNIFTY projecta)  

NASA Astrophysics Data System (ADS)

PKUNIFTY (PeKing University Neutron Imaging FaciliTY), a thermal neutron imaging facility based on a 2 MeV RFQ accelerator, has been constructed at Peking University. Its deuteron injector, which consists of a 2.45 GHz permanent magnet electron cyclotron resonance (PMECR) deuteron ion source and a two-solenoid low energy beam transport (LEBT), aims at producing and delivering 50 mA, 50 keV deuteron beam with a duty factor of 10% (1 ms, 100 Hz). In the preliminary tests of RFQ accelerator, the ECR ion source and LEBT are required to operate at various duty factors (from 1% to 10%). The deuteron ion source has been tested with different pulse widths for this reason. In order to optimize the transmission parameters, the beam current at the exit of RFQ as a function of solenoids tuning and steering magnets tuning are carefully studied. The beam emittance at the entrance of RFQ has been measured with space charge compensation by different argon gas (RG) pressure from 1.6 × 10-4 Pa to 4.7 × 10-3 Pa. The measuring results show the best compensating pressure is 3.5 × 10-3 Pa with a minimal normalized rms emittance of 0.12 pi mm mrad. During the commissioning, we found the purity of deuteron gas is an important factor which severely affects ECR discharge and plasma intensity inside the ion source chamber. The detailed experimental results obtained during the commissioning are discussed in this paper.

Ren, H. T.; Peng, S. X.; Lu, P. N.; Zhao, J.; Zhou, Q. F.; Song, Z. Z.; Yuan, Z. X.; Yu, J. X.; Guo, Z. Y.; Chen, J. E.

2014-02-01

175

Investigation of breakup effects on 6Li + 144Sm scattering by means of CDCC calculations  

NASA Astrophysics Data System (ADS)

The effect of the breakup of the weakly bound 6Li projectile on the elastic channel of the 6Li + 144Sm system is investigated. CDCC calculations are performed by explicitly taking into account the breakup channel and are compared with very precise elastic scattering angular distributions around the Coulomb barrier. The breakup effect is to produce a repulsive polarization potential.

Otomar, D. R.; Lubian, J.; Gomes, P. R. S.

2010-11-01

176

Nonlinear breakup of a coaxial liquid jet in a swirling gas stream  

Microsoft Academic Search

Nonlinear asymmetric breakup of a liquid jet exposed to a swirling gas stream is investigated by a perturbation expansion technique with the initial amplitude of the disturbance as the perturbation parameter. The effects of gas-to-liquid axial velocity ratio and gas swirl number on the liquid jet instability and breakup length have been studied. The breakup length predictions show good agreement

Ashraf A. Ibrahim; Milind A. Jog

2006-01-01

177

Thermal fluctuations and the breakup length of Savart capillary jets  

NASA Astrophysics Data System (ADS)

How long can a capillary jet be before it breaks up into droplets? Much time after the pioneering experimental work of SavartootnotetextF. Savart, Annal. Chim. 53, 337 (1833), plates in Vol. 54. on the breakup of liquid jets isolated from external acoustic noise, no analytical prediction for their length has been derived yet. Even the precise nature of the perturbations leading to the natural breakup of a capillary jet remains a mystery. Only empirically fitted estimates have been proposed up to now, assuming an exponential growth of an unknown initial amplitude of those perturbations. Here, the evolution of a liquid jet emerging from a thin-wall orifice and subjected to thermal-noise fluctuations is explored through a stochastic linear modal analysis. Contrary to what has been assumed before, it is proven that the average amplitude of noisy perturbations does not grow exponentially. For the first time, a simple analytical estimate of the natural breakup length of a liquid jet is derived without the aid of any adjusting parameter. The breakup length of Savart liquid jets exiting through 3mm-diameter orifices are well predicted by this formula. The parametric range of application of this analysis and its accuracy are discussed.

García, F. Javier

2010-11-01

178

When Good Friends Say Goodbye: A Parasocial Breakup Study  

Microsoft Academic Search

This study examines viewers'reactions to parasocial breakup with medi- ated characters in light of interpersonal and mass communication theo- ries. Following the airing of the last episode of the television show Friends, 279 students completed surveys assessing their viewing habits, their attitudes toward the show and their favorite character, and their loneliness. The intensity of the parasocial relationship with the

Keren Eyal; Jonathan Cohen

2006-01-01

179

On causal links between flood basalts and continental breakup  

Microsoft Academic Search

Temporal coincidence between continental flood basalts and breakup has been noted for almost three decades. Eight major continental flood basalts have been produced over the last 300 Ma. The most recent, the Ethiopian traps, erupted in about 1 Myr at 30 Ma. Rifting in the Red Sea and Gulf of Aden, and possibly East African rift started at about the

V. Courtillot; C. Jaupart; I. Manighetti; P. Tapponnier; J. Besse

1999-01-01

180

The Soviet Breakup and U.S. Foreign Policy.  

ERIC Educational Resources Information Center

This issue of a quarterly publication on world affairs explores the historical significance of the disintegration of the Soviet Union and the implication for U.S. foreign policy. With the breakup of the USSR in 1990-91, Russia for the first time this century does not have control over the non-Russian nations of its former empire in Central Asia,…

Lynch, Allen

1991-01-01

181

Breakup of Temperature Inversions in Colorado Mountain Valleys  

Microsoft Academic Search

Tethered balloon observations of temperature inversion breakup have been collected in seven deep Colorado mountain valleys on clear undisturbed weather days in all seasons. By sunrise, the nocturnal inversions (for 21 case studies) build to about the level of the surrounding ridgetops. On average, inversions are 604 m deep with a vertical potential temperature gradient of .0295(DEGREES)K m('-1). The inversions

Charles David Whiteman

1980-01-01

182

NASA's new breakup model of evolve 4.0  

Microsoft Academic Search

Analyses of the fragmentation (due to explosions and collisions) of spacecraft and rocket bodies in low Earth orbit (LEO) have been performed this year at NASA\\/JSC. The overall goals of this study have been to achieve a better understanding of the results of fragmentations on the orbital debris environment and then to implement this understanding into the breakup model of

N. L. Johnson; P. H. Krisko; J.-C. Liou; P. D. Anz-Meador

2001-01-01

183

Current reduction in a pseudo-breakup event: THEMIS observations  

NASA Astrophysics Data System (ADS)

events are thought to be generated by the same physical processes as substorms. This paper reports on the cross-tail current reduction in an isolated pseudo-breakup observed by three of the THEMIS probes (THEMIS A (THA), THEMIS D (THD), and THEMIS E (THE)) on 22 March 2010. During this pseudo-breakup, several localized auroral intensifications were seen by ground-based observatories. Using the unique spatial configuration of the three THEMIS probes, we have estimated the inertial and diamagnetic currents in the near-Earth plasma sheet associated with flow braking and diversion. We found the diamagnetic current to be the major contributor to the current reduction in this pseudo-breakup event. During flow braking, the plasma pressure was reinforced, and a weak electrojet and an auroral intensification appeared. After flow braking/diversion, the electrojet was enhanced, and a new auroral intensification was seen. The peak current intensity of the electrojet estimated from ground-based magnetometers, ~0.7 × 105 A, was about 1 order of magnitude lower than that in a typical substorm. We suggest that this pseudo-breakup event involved two dynamical processes: a current-reduction associated with plasma compression ahead of the earthward flow and a current-disruption related to the flow braking/diversion. Both processes are closely connected to the fundamental interaction between fast flows, the near-Earth ambient plasma, and the magnetic field.

Yao, Z. H.; Pu, Z. Y.; Owen, C. J.; Fu, S. Y.; Chu, X. N.; Liu, J.; Angelopoulos, V.; Rae, I. J.; Yue, C.; Zhou, X.-Z.; Zong, Q.-G.; Cao, X.; Shi, Q. Q.; Forsyth, C.; Du, A. M.

2014-10-01

184

Simulation of Primary Breakup for Diesel Spray with Phase Transition  

NASA Astrophysics Data System (ADS)

We perform direct numerical simulation on large distributed memory parallel computers in order to investigate the primary breakup process of diesel spray direct injection. Local refinement algorithm- Refined level-set method has been used to reduce the memory requirement, and we analyze the performance by experiments on a 1024- processor parallel computer.

Zeng, Peng; Sarholz, Samuel; Iwainsky, Christian; Binninger, Bernd; Peters, Norbert; Herrmann, Marcus

185

Ablation and Breakup of Large Meteoroids during Atmospheric Entry  

Microsoft Academic Search

An ablation model is described that can be used to estimate the effect on a large meteoroid of passage through a planetary atmosphere. The effect on ablation and deceleration of breakup due to aerodynamic pressure is investigated. Results from arc-jet wind-tunnel tests and strength measurements of meteorite samples have been used to help determine the material properties needed in the

Barrett Baldwin; Yvonne Sheaffer

1971-01-01

186

Peregrine soliton generation and breakup in standard telecommunications fiber  

E-print Network

optics and supercontinuum generation [1-2]. These results have motivated a number of studies into the initial dynamics of the supercontinuum generation process, and it was shown in particular1 Peregrine soliton generation and breakup in standard telecommunications fiber Kamal Hammani,1

Paris-Sud XI, Université de

187

Hard Break-Up of Two-Nucleons and QCD Dynamics of NN Interaction  

E-print Network

We discus recent developments in theory of high energy two-body break-up of few-nucleon systems. The characteristics of these reactions are such that the hard two-body quasielastic subprocess can be clearly separated from the accompanying soft subprocesses. We discuss in details the hard rescattering model(HRM) in which hard photodisintegration develops in two stages. At first, photon knocks-out an energetic quark which rescatters subsequently with a quark of the other nucleon. The latter provides a mechanism of sharing the initial high momentum of the photon between two outgoing nucleons. This final state hard rescattering can be expressed through the hard NN scattering amplitude. Within HRM we discuss hard break-up reactions involving D and 3He targets and demonstrate how these reactions are sensitive to the dynamics of hard pn and pp interaction. Another development of HRM is the prediction of new helicity selection mechanism for hard two-body reactions, which was apparently confirmed in the recent JLab experiment.

Misak M. Sargsian

2008-08-27

188

Hard Break-Up of Two-Nucleons and QCD Dynamics of NN Interaction  

NASA Astrophysics Data System (ADS)

We discus recent developments in theory of high energy two-body break-up of few-nucleon systems. The characteristics of these reactions are such that the hard two-body quasielastic subprocess can be clearly separated from the accompanying soft subprocesses. We discuss in details the hard rescattering model (HRM) in which hard photodisintegration develops in two stages. At first, photon knocks-out an energetic quark which rescatters subsequently with a quark of the other nucleon. The latter provides a mechanism of sharing the initial high momentum of the photon between two outgoing nucleons. This final state hard rescattering can be expressed through the hard NN scattering amplitude. Within HRM we discuss hard break-up reactions involving D and 3He targets and demonstrate how these reactions are sensitive to the dynamics of hard pn and pp interaction. Another development of HRM is the prediction of new helicity selection mechanism for hard two-body reactions, which was apparently confirmed in the recent JLab experiment.

Sargsian, Misak

2008-10-01

189

Characteristics of liquid jet atomization across a high-speed airstream. III - Breakup process of liquid jet and internal structure of spray  

Microsoft Academic Search

To elucidate deformation and breakup processes of a liquid jet across an airstream, tomograms of the liquid jet were taken by means of the laser light sheet method. In this method, fluorescent dye, Eosine-Y, was contained in the injected water, and the liquid jet was illuminated by the Nd:YAG laser light sheet. There are two types of atomization mechanisms. In

Tetsuya Oda; Hiroyuki Hiroyasu; Keiya Nishida

1993-01-01

190

PLATYPUS: a code for fusion and breakup in reactions induced by weakly-bound nuclei within a classical trajectory model with stochastic breakup  

E-print Network

A self-contained Fortran-90 program based on a classical trajectory model with stochastic breakup is presented, which should be a powerful tool for quantifying complete and incomplete fusion, and breakup in reactions induced by weakly-bound two-body projectiles near the Coulomb barrier. The code calculates complete and incomplete fusion cross sections and their angular momentum distribution, as well as breakup observables (angle, kinetic energy and relative energy distributions).

Diaz-Torres, Alexis

2007-01-01

191

PLATYPUS: a code for fusion and breakup in reactions induced by weakly-bound nuclei within a classical trajectory model with stochastic breakup  

E-print Network

A self-contained Fortran-90 program based on a classical trajectory model with stochastic breakup is presented, which should be a powerful tool for quantifying complete and incomplete fusion, and breakup in reactions induced by weakly-bound two-body projectiles near the Coulomb barrier. The code calculates complete and incomplete fusion cross sections and their angular momentum distribution, as well as breakup observables (angle, kinetic energy and relative energy distributions).

Alexis Diaz-Torres

2007-12-14

192

Effect of breakup processes on the near-barrier elastic scattering of the 6,7Li + 232Th systems  

NASA Astrophysics Data System (ADS)

Elastic scattering angular distribution measurements of the weakly bound 6,7Li projectiles on a 232Th target have been carried out at different bombarding energies close to the Coulomb barrier. The data have been analyzed for both systems using the optical model ecis code with phenomenological Woods-Saxon and Sao Paulo double-folding forms of the optical potentials. The energy dependence of the volume-type real and imaginary parts of the optical potentials are derived from the best fit of the experimental angular distribution data. The usual threshold anomaly has been observed for the 7Li + 232Th system, whereas there is an indication of a breakup threshold anomaly in case of the 6Li + 232Th system. Results on total reaction cross sections obtained from the optical model analysis for both systems have been interpreted to understand the role of projectile breakup on the reaction mechanism.

Dubey, Shradha; Mukherjee, S.; Biswas, D. C.; Nayak, B. K.; Patel, D.; Prajapati, G. K.; Gupta, Y. K.; Joshi, B. N.; Danu, L. S.; Mukhopadhyay, S.; John, B. V.; Desai, V. V.; Suryanarayana, S. V.; Vind, R. P.; Deshmukh, N. N.; Appnnababu, S.; Prajapati, P. M.

2014-01-01

193

High deuteron polarization in trityl radical doped deuterated polystyrene  

NASA Astrophysics Data System (ADS)

Deuterated polystyrene for polarized solid targets has been prepared by chemical doping with the trityl radical ‘Finland D36’ (AH 110 355 deutero acid form). Thin foils doped with various radical densities have been produced using tetrahydrofuran as solvent. Dynamic nuclear polarization technique has been applied to polarize deuterons in the samples (98%-D) at the temperature range of about 1 K and magnetic fields of 2.5 T and 5.0 T. A maximum deuteron polarization of -61.5% with a build-up time of 100 min has been achieved at 5.0 T and about 500 mK at a radical density of 1.16×1019 spins/g.

Wang, Li; Berlin, A.; Doshita, N.; Herick, J.; Hess, C.; Iwata, T.; Kondo, K.; Meyer, W.; Reicherz, G.

2013-11-01

194

Progress on a Polarimeter for the Deuteron EDM Search  

NASA Astrophysics Data System (ADS)

The design of the storage ring for the deuteron electric dipole moment (EDM) search uses crossed E and B fields to nearly stop the magnetic moment precession of the deuteron in the ring bending magnets. This allows time for the EDM (whose predession is based on E=?vxB) to generate a detectable vertical polarization component [1]. A polarimeter for the EDM ring must monitor continuously and with high statistical precision. Recent tests at COSY-J"ulich have demonstrated high efficiency (˜1.5%) using a thick-walled carbon tube target that also determines the ring aperture. Extraction onto the target was tested using beam position ramping and beam heating with a cluster jet target or a white-noise electric field. Systematic errors were investigated. Continuous monitoring demonstration measurements were made using an RF solenoid whose frequency was ramped through the 1-G? depolarizing resonance.[1] F.J. Farley et al, Phys. Rev. Lett. 93. 052001 (2004).

Stephenson, E. J.

2008-10-01

195

Deuteron Spin Structure Functions in the Resonance and DIS Regions  

SciTech Connect

We derive relations between spin-dependent nuclear and nucleon g_1 and g_2 structure functions, valid at all Q^2, and in both the resonance and deep inelastic regions. We apply the formalism to the specific case of the deuteron, which is often used as a source of neutron structure information, and compare the size of the nuclear corrections calculated using exact kinematics and using approximations applicable at large Q^2.

S. Kulagin; W. Melnitchouk

2007-10-03

196

Deuteron NMR Study of Monolayer Thick Films of Nematogenic Molecules  

Microsoft Academic Search

We present a deuteron NMR study of molecular thickness films of a nematogenic material in cylindrical pores. Compared to liquid crystal in bulk or completely filling the pores, a reduced quadrupole splitting is found. It strongly depends on thickness, but only weakly on temperature, even crossing the bulk nematic-isotropic transition. This demonstrates the presence of a 2D-like film that eventually

Bostjan Zalar; Slobodan Zumer; Daniele Finotello

2000-01-01

197

Effective Theory for Neutron-Deuteron Scattering and the Triton  

Microsoft Academic Search

We apply the effective field theory approach to the three-nucleon system. In particular, we consider neutron-deuteron scattering and the triton. Precise predictions for S=3\\/2 scattering are obtained in a straightforward way. In the S=1\\/2 channel, however, a unique nonperturbative renormalization takes place which requires the introduction of a three-body force at leading order. We also show that invariance under the

H.-W. Hammer

1999-01-01

198

Deuteron irradiation creep of chemically vapor deposited silicon carbide fibers  

Microsoft Academic Search

Irradiation creep tests were conducted on Textron SCS-6 silicon carbide (SiC) fibers during irradiation with 14 MeV deuterons at 450 and 600°C. The fibers are produced by a CVD procedure; their microstructure may therefore be representative for the matrix of a SiC composite. There is a significant radiation induced increase in creep deformation. Both quantities, irradiation creep strain and creep

R. Scholz

1998-01-01

199

THE SACLAY HIGH-CURRENT PROTON AND DEUTERON ECR SOURCE  

Microsoft Academic Search

High-current accelerators are studied for several years at CEA-Saclay for applications such as waste transmutation, tritium production or material irradiation. For these projects, the ion source is a key component because its performances determine the accelerator design. A CW Proton and Deuteron ECR Source has been constructed and is now under test. The aim is to reach a 100mA beam

P-Y Beauvais; O. Delferriere; R. Ferdinand; R. Gobin; J. M. Lagniel; P. A. Leroy

200

Applications of MeV proton and deuteron linear accelerators  

Microsoft Academic Search

There are a number of applications, either proposed, currently under development or already reduced to practice, that utilize proton or deuteron beams in the 1-10 MeV energy regime. These applications have been reviewed and the accelerator requirements summarized. In terms of the beam time-structure, nearly all of the applications fall into three broad categories. (1) Beams that utilize nanosecond pulses

George H. Gillespie; G. E. McMichael

1995-01-01

201

Deuteron-nucleus collisions in a multiphase transport model  

E-print Network

is organized as follows. In Sec. II, we briefly review the AMPT model. Results from the AMPT model on deuteron-gold collisions at RHIC are then shown in Sec. III, with the charged particle pseudorapidity distributions and their centrality dependence given..., the effect of centrality selec- tion on the centrality dependence of charged particle pseudo- rapidity distributions is discussed in the Appendix. II. THE AMPT MODEL The AMPT model is a hybrid model that consists of four components: the initial...

Lin, ZW; Ko, Che Ming.

2003-01-01

202

Nucleon charge exchange on the deuteron: A critical review  

E-print Network

The existing experimental data on the d(n,p)nn and d(p,n)pp cross sections in the forward direction are reviewed in terms of the Dean sum rule. It is shown that the measurement of the ratio of the charge exchange on the deuteron to that on the proton might, if taken together with other experimental data, allow a direct construction of the np -> np scattering amplitude in the backward direction with few ambiguities.

Francois Lehar; Colin Wilkin

2008-05-20

203

Spin structure functions: Proton / deuteron measurements in the resonance region  

SciTech Connect

The RSS experiment ran in Hall C at Jefferson Lab and measured the proton and deuteron beam-target asymmetries for parallel and perpendicular target fields over a W range from pion threshold to 1.9 GeV at Q{sup 2} {approx} 1.3 GeV{sup 2}. Preliminary results for the proton spin structure functions g{sub 1} and g{sub 2} are presented.

Mark Jones; RSS Collaboration

2006-02-01

204

The root-mean-square radius of the deuteron  

Microsoft Academic Search

Re-examines the determination of the root-mean square radius of the deuteron (rd) from the appropriate experimentally determined electric form factors, GEd, GEp, GEd\\/GEp and GEn. With a particular extrapolation of results from realistic NN interactions and a specific assumption regarding the shape of GEn for small q2 consistent with a recent quark-model calculation the authors obtain rd=1.952+or-0.004 fm. Their model-independent

L. J. Allen; J. P. McTavish; M. W. Kermode; A. McKerrell

1981-01-01

205

Deuteron Beam Driven Fast Ignition of a Pre-Compressed Inertial Confinement Fusion (ICF) Target  

NASA Astrophysics Data System (ADS)

Fast Ignition (FI) is recognized as the most promising approach to achieving the high energy gain target performance needed for commercial inertial confinement fusion (ICF). Deuteron beams not only provide heating via linear energy transfer when slowing down, but can also provide extra ?bonus? fusion energy through reactions in the target. In view of the recent observation of ultra-high-density deuterium clusters, in addition to the extra energy gain expected from the deuterons, we estimate the impact of the added deposition energy from the deuteron beam to the target fuel based on calculations using a modified energy multiplication factor Fc. The deuteron beam energy deposition range and time are also calculated in order to estimate optimized deuteron initial energy. The aim of this study is to explore the potential advantages of a deuteron beam driven FI scheme for ICF. However, a much more comprehensive calculation is needed to realize a full 3D experimental design for maximum fusion gain.

Yang, Xiaoling; Miley, George; Flippo, Kirk; Hora, Heinrich

2010-11-01

206

Can one extract the pi-neutron scattering length from pi-deuteron scattering?  

E-print Network

We give a prove of evidence that the original power counting by Weinberg can be applied to estimate the contributions of the operators contributing to the pi-deuteron scattering length. As a consequence, pi-deuteron observables can be used to extract neutron amplitudes--in case of pi-deuteron scattering this means that the pi-neutron scattering length can be extracted with high accuracy. This result is at variance with recent claims. We discuss the origin of this difference.

A. Nogga; C. Hanhart

2005-11-02

207

On extraction of the total photoabsorption cross section on the neutron from data on the deuteron  

E-print Network

An improved procedure is suggested for finding the total photoabsorption cross section on the neutron from data on the deuteron at energies < 1.5 GeV. It includes unfolding of smearing effects caused by Fermi motion of nucleons in the deuteron and also takes into account non-additive contributions to the deuteron cross section due to final-state interactions of particles in single and double pion photoproduction. This procedure is applied to analysis of existing data.

M. I. Levchuk; A. I. L'vov

2013-01-21

208

On extraction of the total photoabsorption cross section on the neutron from data on the deuteron  

E-print Network

An improved procedure is suggested for finding the total photoabsorption cross section on the neutron from data on the deuteron at energies < 1.5 GeV. It includes unfolding of smearing effects caused by Fermi motion of nucleons in the deuteron and also takes into account non-additive contributions to the deuteron cross section due to final-state interactions of particles in single and double pion photoproduction. This procedure is applied to analysis of existing data.

Levchuk, M I

2013-01-01

209

Dynamics of Cold-Air Pool Breakup: Numerical Simulations  

NASA Astrophysics Data System (ADS)

Persistent cold-air pools (CAPs) impact urban mountain valleys during the winter leading to prolonged episodes of unhealthy air quality. One associated scientific challenge is accurately forecasting the breakup of these CAPs. For example, there is often uncertainty regarding the interaction of passing weather systems with the stratification within a valley. Will the disturbance be sufficient to destroy the CAP, or will the CAP persist for many more days bringing continued elevated levels of pollution? To address these questions this study examines the dynamical processes that affect the time scale and character of CAP breakup. To do so we use idealized large eddy simulations (LES) to examine the sensitivity of CAP removal to variations in wind, topography, and stratification. The simulations are based on field observations from the Persistent Cold-Air Pool Study (PCAPS). Results indicate that the upstream terrain-flow interaction is important in controlling both the timescale and structure of the CAP breakup. For example, when the flow plunges over the confining topography it leads to enhanced turbulent mixing, CAP displacement, and shorter timescales for complete CAP removal. In contrast, when no mountain wave is present the upstream edge of the CAP remains sheltered from the wind-driven mixing and the break-up is first observed over downstream portions of the basin. Meanwhile, changes in the CAP stratification impact internal circulations that develop in response to the imposed wind forcing. These circulations have significance for the distribution of pollution within CAPs. A concise summary of these results will be presented. Snapshot from a simulation of strong winds disrupting a CAP confined between two ridges. Potential temperature (a), vertical velocity (b), and wind speed (c).

Lareau, N.; Horel, J.

2013-12-01

210

JET BREAKUP AND SPRAY FORMATION IN A DIESEL ENGINE.  

SciTech Connect

The breakup of injected fuel into spray is of key interest to the design of a fuel efficient, nonpolluting diesel engine. We report preliminary progress on the numerical simulation of diesel fuel injection spray with the front tracking code FronTier. Our simulation design is set to match experiments at ANL, and our present agreement is semi-quantitative. Future efforts will include mesh refinement studies, which will better model the turbulent flow.

GLIMM,J.; LI,X.; KIM,M.N.; OH,W.; MARCHESE,A.; SAMULYAK,R.; TZANOS,C.

2003-06-17

211

Cryogenic liquid-jet breakup in two-fluid atomizers  

NASA Technical Reports Server (NTRS)

A two-fluid atomizer was used to study the breakup of liquid-nitrogen jets in nitrogen, argon, and helium atomizing gas flows. A scattered-light scanner particle sizing instrument previously developed at NASA Lewis Research Center was further developed and used to determine characteristic drop diameters for the cryogenic sprays. In the breakup regime of aerodynamic-stripping, i.e., sonic-velocity conditions, the following correlation of the reciprocal Sauter mean diameter, D(sub 32)exp -1, with the atomizing-gas flowrate, W(g), was obtained: D(sub 32)exp -1 = k(sub c)(W(g)exp 1.33), where k(sub c) is a proportionality constant evaluated for each atomizing gas. Values of k(sub c) = 120, 220, and 1100 were obtained for argon, nitrogen, and helium gasflows, respectively. The reciprocal Sauter mean diameter and gas flowrate have the units of 1/cm and g/sec, respectively. In the regime of capillary-wave breakup, or subsonic conditions, it was found that D(sub 32)exp -1 = k(g)(W(g)exp 0.75), where k = 270, 390, and 880 for argon, nitrogen, and helium gasflows, respectively.

Ingebo, Robert D.

1991-01-01

212

Breakup of small aggregates driven by turbulent hydrodynamic stress  

E-print Network

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 statistics of the hydrodynamic stress exhibit some deficiencies. These are discussed by investigating the evolution of an ensemble of aggregates undergoing breakup and aggregation.

Matthaus U. Babler; Luca Biferale; Alessandra S. Lanotte

2012-01-24

213

Transverse liquid fuel jet breakup, burning, and ignition  

SciTech Connect

An analytical/numerical study of the breakup, burning, and ignition of liquid fuels injected transversely into a hot air stream is conducted. The non-reacting liquid jet breakup location is determined by the local sonic point criterion first proposed by Schetz, et al. (1980). Two models, one employing analysis of an elliptical jet cross-section and the other employing a two-dimensional blunt body to represent the transverse jet, have been used for sonic point calculations. An auxiliary criterion based on surface tension stability is used as a separate means of determining the breakup location. For the reacting liquid jet problem, a diffusion flame supported by a one-step chemical reaction within the gaseous boundary layer is solved along the ellipse surface in subsonic crossflow. Typical flame structures and concentration profiles have been calculated for various locations along the jet cross-section as a function of upstream Mach numbers. The integrated reaction rate along the jet cross-section is used to predict ignition position, which is found to be situated near the stagnation point. While a multi-step reaction is needed to represent the ignition process more accurately, the present calculation does yield reasonable predictions concerning ignition along a curved surface.

Li, H.

1990-01-01

214

Transverse liquid fuel jet breakup, burning, and ignition  

SciTech Connect

An analytical/numerical study of the breakup, burning, and ignition of liquid fuels injected transversely into a hot air stream is conducted. The non-reacting liquid jet breakup location is determined by the local sonic point criterion first proposed by Schetz, et al. (1980). Two models, one employing analysis of an elliptical jet cross-section and the other employing a two-dimensional blunt body to represent the transverse jet, have been used for sonic point calculations. An auxiliary criterion based on surface tension stability is used as a separate means of determining the breakup location. For the reacting liquid jet problem, a diffusion flame supported by a one-step chemical reaction within the gaseous boundary layer is solved along the ellipse surface in subsonic crossflow. Typical flame structures and concentration profiles have been calculated for various locations along the jet cross-section as a function of upstream Mach numbers. The integrated reaction rate along the jet cross-section is used to predict ignition position, which is found to be situated near the stagnation point. While a multi-step reaction is needed to represent the ignition process more accurately, the present calculation does yield reasonable predictions concerning ignition along a curved surface.

Li, H.

1990-12-31

215

Structure and evolution of a magmatic rift segment close to continental breakup  

NASA Astrophysics Data System (ADS)

The continental-oceanic transition (OCT) at volcanic margins is often associated with large volcanic provinces and with specific tecto/volcanic structures, notably seaward dipping reflectors (SDRs), of which the origin and processes of formation are still debated. The Afar province corresponds to the very last observable stages of continental rifting before breakup. Interestingly, in this area where the continental crust remains ~20 km thick, magmatism and tectonic activity are already clearly expressed in well-individualised rift segments, presenting the morphological characteristics of mature oceanic ridges. The Afar region therefore represents an ideal natural laboratory to study the processes responsible for maintaining magmatic accretion and their links with the distribution of deformation in a pre-breakup context. We have focussed on the Dabbahu segment that experienced a diking event in 2005 that has been studied in detail. The subsequent tectono-volcanic crisis that lasted 5 years, has provided invaluable information on the mechanisms controlling dyke intrusion, the main process responsible for extension at the scale of a single rifting event. Our investigations focussed on the 1 to 100 kyrs timescales - a key period over which the main morphology of a rift/ridge segment is acquired, but which currently lacks chronological constraints. In order to bridge this gap in temporal evolution, our multidisciplinary approach combines surface exposure dating (3He and 36Cl) of lavas and fault scarps with major & trace element compositions and field/remote sensing mapping of the Dabbahu rift. Our results show that accretion is maintained by individual magmatic chambers, distributed along the active rift segment. There, we have identified magmatic cycles of 30-40 kyrs duration during which the magmas progressively differentiate, until the magmatic centre is abandoned. These cycles exert a strong control on the building of topography: the tectonic activity is subdued during the active phases of the magma chamber, and are enhanced when the magmatic activity decreases. Our measurements show that the fault scarps have a continuous slip rate along the neo-volcanic zone, between 1-2 mm/yr. We also identify several individual palaeo-tectonic events of metric amplitude (very similar to the 2005 crisis) which suggest that the main process responsible for the building of the axial depression is indeed dike intrusions. This implies that in pre-breakup stages accretion is already organised and maintained by processes similar to those occurring in mature oceanic ridges. The question arises to know if these mechanisms, observed here on the scale of a few tens of kyrs, could be responsible for the creation of SDRs, implying these mechanisms operate on timescales of a few million years.

Medynski, Sarah; Pik, Raphaël; Burnard, Peter; Stab, Martin; Vye-Brown, Charlotte; France, Lyderic

2014-05-01

216

The breakup sequence and associated lithospheric breakup surface: Their significance in the context of rifted continental margins (West Iberia and Newfoundland margins, North Atlantic)  

NASA Astrophysics Data System (ADS)

Regional (2D) seismic-reflection profiles and borehole data are used to characterise the syn- to post-rift transition in the shallow offshore Porto Basin, and in deep-offshore regions of West Iberia and Newfoundland (East Canada). The interpreted data highlight the development of a regional stratigraphic surface at the time of complete lithospheric breakup between West Iberia and Newfoundland. This surface, usually called "breakup unconformity", is renamed in this work as Lithospheric Breakup Surface (LBS), on the basis that: (1) it is not always developed as an unconformity and (2) all lithosphere is involved on the breakup process, not only the continental crust. Depositional changes occur across the LBS in association with Late Aptian lithospheric breakup, which is marked by the deposition of a breakup sequence (BS) rather than a single stratigraphic surface. Stratigraphic correlations between strata in shallow and deeper parts of the two margins lead us to propose the breakup sequence (BS) as representing the transitional period between lithospheric breakup and the establishment of thermal relaxation as the main process controlling subsidence on divergent continental margins. The results in this work are important for other continental margins as they demonstrate that during lithospheric breakup significant quantities of sediment bypassed the inner proximal margins of West Iberia and Newfoundland on their way to the outer proximal margin. In addition, the interpreted data show that complete lithospheric breakup between conjugate margins is recorded by similar tectono-stratigraphic events. In Iberia and Newfoundland, these events are associated with reservoir successions in sediment overfilled basins and with carbon-rich strata ('black shales') in sediment-starved basins.

Soares, Duarte M.; Alves, Tiago M.; Terrinha, Pedro

2012-11-01

217

Aerodynamic effects in the break-up of liquid jets: on the first wind-induced break-up regime  

Microsoft Academic Search

We present both numerical and analytical results from a spatial stability analysis of the coupled gas liquid hydrodynamic equations governing the first wind-induced (FWI) liquid-jet break-up regime. Our study shows that an accurate evaluation of the growth rate of instabilities developing in a liquid jet discharging into a still gaseous atmosphere requires gas viscosity to be included in the stability

J. M. Gordillo; M. Pérez-Saborid

2005-01-01

218

arXiv:nucl-ex/0002003v225Feb2000 Phenomenology of the deuteron electromagnetic form factors  

E-print Network

arXiv:nucl-ex/0002003v225Feb2000 Phenomenology of the deuteron electromagnetic form factors D. The parameterizations allow a phenomenological characterization of the deuteron electromagnetic struc- ture. They can

Thomas Jefferson National Accelerator Facility

219

First observation of spin dichroism with deuterons up to 20 MeV in a carbon target  

E-print Network

The first observation of the phenomenom of deuteron spin dichroism in the energy region of 6-20 MeV is described. Experimental values of this effect for deuterons after passage of an unpolarized carbon target are reported.

V. Baryshevsky; A. Rouba; R. Engels; F. Rathmann; H. Seyfarth; H. Ströher; T. Ullrich; C. Düweke; R. Emmerich; A. Imig; J. Ley; H. Paetz gen. Schieck; R. Schulze; G. Tenckhoff; C. Weske; M. Mikirtytchiants; A. Vassiliev

2005-01-18

220

Coalescence and Breakup of Oppositely Charged Droplets  

PubMed Central

The coalescence process of oppositely charged drops for different electrical conductivities of liquids is presented. When the electrical conductivity was relatively low, oppositely charged drops failed to coalesce under sufficiently high electrical fields and capillary ripples were formed on the surfaces of droplets after rebound. For a high electrically conductive liquid, it was found that a crown profile of drop fission always appeared on the top surface of negatively charged drops after the two charged drops contacted and bounced off. Furthermore, we report here, for the first time, the newly found phenomenon and argue that the break up might be caused by Rayleigh instability, a form of Coulomb fission. The different mobility of positive and negative ions is the underlying mechanism that explains why the break up always happened on the negative side of charged drops. PMID:25410022

Wang, Junfeng; Wang, Bin; Qiu, Huihe

2014-01-01

221

Systematic study of breakup effects on complete fusion at energies above the Coulomb barrier  

NASA Astrophysics Data System (ADS)

A large number of complete fusion excitation functions of reactions including the breakup channel were measured in recent decades, especially in the last few years. It allows us to investigate the systematic behavior of the breakup effects on the complete fusion cross sections. To this end, we perform a systematic study of the breakup effects on the complete fusion cross sections at energies above the Coulomb barrier. The reduced fusion functions F (x) are compared with the universal fusion function which is used as a uniform standard reference. The complete fusion cross sections at energies above the Coulomb barrier are suppressed by the breakup of projectiles. This suppression effect for reactions induced by the same projectile is independent of the target and mainly determined by the lowest energy breakup channel of the projectile. A good exponential relation between the suppression factor and the energy corresponding to the lowest breakup threshold is held.

Wang, Bing; Zhao, Wei-Juan; Gomes, P. R. S.; Zhao, En-Guang; Zhou, Shan-Gui

2014-09-01

222

Characterization of the 2012-044C Briz-M Upper Stage Breakup  

NASA Technical Reports Server (NTRS)

The NASA breakup model prediction was close to the observed population for catalog objects. The NASA breakup model predicted a larger population than was observed for objects under 10 cm. The stare technique produces low observation counts, but is readily comparable to model predictions. Customized stare parameters (Az, El, Range) were effective to increase the opportunities for HAX to observe the debris cloud. Other techniques to increase observation count will be considered for future breakup events.

Hamilton, Joseph A.; Matney, Mark

2013-01-01

223

Low-Energy Neutron-Deuteron Scattering; RASSEYANIE NEITRONOV NA DEITRONAKH PRI MALYKH ENERGIYAKH  

Microsoft Academic Search

The S-scattering phases of neutrons on deuterons at low energies were ; calculated by using the variational method with account of the deuteron ; deformation. The nucleon interaction was assumed to be central, charge-; invariant and to have a charge exchange character. The radial dependence of the ; potential of nuclear forces was chosen in the form of the Gaussian

Efimov

1963-01-01

224

Investigation of the deuteron spin structure at short nucleon-nucleon distances in the reaction of polarized-deuteron fragmentation to cumulative pions  

SciTech Connect

Experimental results on the vector (A{sub y}) and tensor (A{sub yy}) analyzing powers in the fragmentation of 5- and 9-GeV/c polarized deuterons to high-momentum pions in the kinematical region corresponding to pion production on a strongly correlated nucleon pair (cumulative meson production) are presented. The angular and momentum dependences of A{sub yy} are not described by calculations performed in the impulse approximation by using standard deuteron wave functions. An explanation for our data should be sought on the basis of models that treat the deuteron at short distances (deuteron-core region) as a multiquark state-for example, a 6q cluster, whose high orbital angular momentum (D wave) leads to the observed strong dependence of the reaction tensor analyzing power A(d-vector, {pi})X on the pion transverse momentum.

Azhgirey, L. S.; Afanasiev, S. V.; Borzounov, Yu. T.; Golovanov, L. B.; Zolin, L. S., E-mail: zolin@sunhe.jinr.ru; Ivanov, V. I.; Isupov, A. Yu., E-mail: isupov@moonhe.jinr.ru; Ladygin, V. P.; Litvinenko, A. G.; Malakhov, A. I.; Penev, V. N.; Peresedov, V. F.; Pilipenko, Yu. K.; Reznikov, S. G.; Rukoyatkin, P. A.; Khrenov, A. N. [Joint Institute for Nuclear Research (Russian Federation)

2011-10-15

225

Effective Theory for Neutron-Deuteron Scattering and the Triton  

E-print Network

We apply the effective field theory approach to the three-nucleon system. In particular, we consider neutron-deuteron scattering and the triton. Precise predictions for S=3/2 scattering are obtained in a straightforward way. In the S=1/2 channel, however, a unique nonperturbative renormalization takes place which requires the introduction of a three-body force at leading order. We also show that invariance under the renormalization group explains some universal features of the three-nucleon system.

Hammer, H W

1999-01-01

226

Effective Theory for Neutron-Deuteron Scattering and the Triton  

E-print Network

We apply the effective field theory approach to the three-nucleon system. In particular, we consider neutron-deuteron scattering and the triton. Precise predictions for S=3/2 scattering are obtained in a straightforward way. In the S=1/2 channel, however, a unique nonperturbative renormalization takes place which requires the introduction of a three-body force at leading order. We also show that invariance under the renormalization group explains some universal features of the three-nucleon system.

H. -W. Hammer

1999-05-18

227

Effective Theory for Neutron-Deuteron Scattering and the Triton  

Microsoft Academic Search

We apply the effective field theory approach to the three-nucleon system. In\\u000aparticular, we consider neutron-deuteron scattering and the triton. Precise\\u000apredictions for S=3\\/2 scattering are obtained in a straightforward way. In the\\u000aS=1\\/2 channel, however, a unique nonperturbative renormalization takes place\\u000awhich requires the introduction of a three-body force at leading order. We also\\u000ashow that invariance under the

H.-W. Hammer

1999-01-01

228

Deuteron irradiation creep of chemically vapor deposited silicon carbide fibers  

NASA Astrophysics Data System (ADS)

Irradiation creep tests were conducted on Textron SCS-6 silicon carbide (SiC) fibers during irradiation with 14 MeV deuterons at 450 and 600°C. The fibers are produced by a CVD procedure; their microstructure may therefore be representative for the matrix of a SiC composite. There is a significant radiation induced increase in creep deformation. Both quantities, irradiation creep strain and creep rate, are higher at 450°C than at 600°C for doses <0.07 dpa.

Scholz, R.

1998-03-01

229

Two-photon exchange in electron deuteron scattering  

E-print Network

It is shown that the amplitude of elastic ed scattering beyond Born approximation contains six generalized form factors, but only three linearly independent combinations of them (generalized charge, quadrupole and magnetic form factors) contribute to the reaction cross section in the second order perturbation theory. We examine two-photon exchange and find that it includes two types of diagrams, when two virtual photons interact with the same nucleon and when the photons interact with different nucleons.We discuss contribution of the two-photon exchange in reaction observables, generalized \\mathcal A and \\mathcal B structure functions and tensor polarization of the deuteron.

A. P. Kobushkin; Ya. D. Krivenko-Emetov

2011-01-10

230

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

E-print Network

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...

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

2010-01-01

231

Observations of breakup processes of liquid jets using real-time X-ray radiography  

NASA Technical Reports Server (NTRS)

To unravel the liquid-jet breakup process in the nondilute region, a newly developed system of real-time X-ray radiography, an advanced digital image processor, and a high-speed video camera were used. Based upon recorded X-ray images, the inner structure of a liquid jet during breakup was observed. The jet divergence angle, jet breakup length, and fraction distributions along the axial and transverse directions of the liquid jets were determined in the near-injector region. Both wall- and free-jet tests were conducted to study the effect of wall friction on the jet breakup process.

Char, J. M.; Kuo, K. K.; Hsieh, K. C.

1988-01-01

232

An Analysis of Recent Major Breakups in the Low Earth Orbit Region  

NASA Technical Reports Server (NTRS)

Of the 4 recent major breakup events, the FY-1C ASAT test and the collision between Iridium 33 and Cosmos 2251 generated the most long-term impact to the environment. About half of the fragments will still remain in orbit at least 20 years after the breakup. The A/M distribution of the Cosmos 2251 fragments is well-described by the NASA Breakup Model. Satellites made of modern materials (such as Iridium 33), equipped with large solar panels, or covered with large MLI layers (such as FY-1C) may generated significant amount of high A/M fragments upon breakup.

Liou, J.-C.; Anz-Meador, P. D.

2010-01-01

233

Tensor electric polarizability of the deuteron in storage-ring experiments  

E-print Network

The tensor electric polarizability of the deuteron gives important information about spin-dependent nuclear forces. If a resonant horizontal electric field acts on a deuteron beam circulating into a storage ring, the tensor electric polarizability stimulates the buildup of the vertical polarization of the deuteron (the Baryshevsky effect). General formulas describing this effect have been derived. Calculated formulas agree with the earlier obtained results. The problem of the influence of tensor electric polarizability on spin dynamics in such a deuteron electric-dipole-moment experiment in storage rings has been investigated. Doubling the resonant frequency used in this experiment dramatically amplifies the Baryshevsky effect and provides the opportunity to make high-precision measurements of the deuteron's tensor electric polarizability.

Alexander J. Silenko

2006-05-08

234

Plate break-up geometry in SE-Afar  

NASA Astrophysics Data System (ADS)

New structural data acquired in Djibouti strongly support the view of a magma-rich to magma-poor pair of conjugate margins developed in SE Afar since at least 9 Ma. Our model is illustrated by a crustal-scale transect that emphasizes the role of a two-stage extensional detachment fault system, with opposing senses of motion through time. The geometry and kinematics of this detachment fault pattern are mainly documented from lavas and fault dip data extracted from remote sensing imagery (Landsat ETM+, and corresponding DEM), further calibrated by field observations. Although expressed by opposite fault geometries, the two successive extensional events evidenced here are part of a two-stage continental extensional tear-system associated with the ongoing propagation of the Aden-Tadjoura oceanic axis to the NW. A flip-flop evolution of detachment faults accommodating lithosphere divergence has recently been proposed for the development of the Indian Ocean and continental margins (Sauter et al., 2013). However, the SE Afar evolution further suggests a radical and sudden change in lithosphere behavior during extension, from a long-term and widespread magmatic stage to a syn-sedimentary break-up stage where mantle melting concentrates along the future oceanic axis. Of special interest is the fact that a late and rapid stage of non-magmatic extension led to break-up, whose geometry triggered the location of the break-up axis and earliest oceanic accretion. New structural data acquired in Djibouti strongly support the view of a magma-rich to magma-poor pair of conjugate margins developed in SE Afar since at least 9 Ma. Our model is illustrated by a crustal-scale transect that emphasizes the role of a two-stage extensional detachment fault system, with opposing senses of motion through time. The geometry and kinematics of this detachment fault pattern are mainly documented from lavas and fault dip data extracted from remote sensing imagery (Landsat ETM+, and corresponding DEM), further calibrated by field observations. Although expressed by opposite fault geometries, the two successive extensional events evidenced here are part of a two-stage continental extensional tear-system associated with the ongoing propagation of the Aden-Tadjoura oceanic axis to the NW. A flip-flop evolution of detachment faults accommodating lithosphere divergence has recently been proposed for the development of the Indian Ocean and continental margins (Sauter et al., 2013). However, the SE Afar evolution further suggests a radical and sudden change in lithosphere behavior during extension, from a long-term and widespread magmatic stage to a syn-sedimentary break-up stage where mantle melting concentrates along the future oceanic axis. Of special interest is the fact that a late and rapid stage of non-magmatic extension led to break-up, whose geometry triggered the location of the break-up axis and earliest oceanic accretion.

Geoffroy, Laurent; Le Gall, Bernard; Daoud, Mohamed

2014-05-01

235

Tear Film Images and Breakup Analyzed Using Fluorescent Quenching  

PubMed Central

Purpose. Tear evaporation should increase fluorescein concentration, causing fluorescence dimming from self-quenching for high but not low fluorescein concentration. This prediction was tested and compared to the predicted effect of “tangential flow” that fluorescence dimming should be similar for high and low concentrations. Methods. A custom optical system was used for video recording of tear film fluorescence in 30 subjects. The subjects were asked to blink at the start of the recording and try to keep their eyes open for the rest of the 60-second recording. An initial recording was made after instillation of 1 ?L 0.1% fluorescein followed by further recordings at 5-minute intervals using 0.5% and 5% fluorescein. Results. Decay of fluorescence was considerably greater for the high (5%) concentration condition than for the low (0.1%) concentration. This is shown by “ratio images” (ratio of the intensity of a fluorescence image at a later time divided by that of an earlier image), fluorescence decay curves, fluorescence decay rates, and histograms of estimated tear thickness decrease. For example, for the high concentration condition, decay rates were higher than for the low concentration for all 30 subjects (P < 0.0001, binomial test). Additionally, breakup time was significantly reduced for the high compared to the low concentration condition. Conclusions. The greater fluorescence decay and more rapid breakup for the high concentration condition are the results expected if thinning and breakup are mainly due to evaporation, hence causing self-quenching. Fluorescence decay rate for the low concentration condition was not significantly greater than zero. PMID:23920365

King-Smith, P. Ewen; Ramamoorthy, Padmapriya; Braun, Richard J.; Nichols, Jason J.

2013-01-01

236

Theoretical quantum chemical study of protonated - deuteronated PAHs: Interstellar implications  

NASA Astrophysics Data System (ADS)

Diffuse Interstellar Bands (DIBs) are optical absorption features on the interstellar extinction curve. Ultra-high resolution spectroscopic observations suggest that at least some of these features are due to large molecules. Observational results also reveal that the strengths of the DIBs are not strongly correlated with each other, implying that there must be several carriers. Considering the wide range of interstellar species and the cost and duration of experimental work that is involved to determine the carriers of DIBs, Density Functional Theory (DFT) and Time Dependent Density Functional Theory (TDDFT) calculations offer opportunities to investigate which molecules are suitable for laboratory studies. The widespread presence of Polycyclic Aromatic Hydrocarbons (PAHs) in astrophysical environments is known from observations of the Unidentified Infrared (UIR) emission bands. Since PAHs are stable enough to be present under interstellar conditions, they are good candidates to be the carriers of the DIBs. We report DFT and TDDFT calculations to predict electronic transitions of neutral as well as protonated-deuteronated PAHs with various sites of protonation and deuteronation. The PAH molecules considered for calculation include pyrene, perylene, coronene and heptacene. Compared to their neutral forms, these charged isoelectronic forms of PAHs are predicted to have active transitions in the visible region, which means they are suitable candidates as carriers for some of the DIBs.

Buragohain, Mridusmita; Pathak, Amit; Hammonds, Mark; Sarre, Peter J.

2013-06-01

237

Dispersions of pyrogenic alumina in pentylcyanobiphenyl studied by deuteron NMR  

NASA Astrophysics Data System (ADS)

Dispersions of hydrophilic (Aeroxide Alu C) and hydrophobic (Aeroxide Alu C 805) pyrogenic alumina (Al2O3) in liquid crystal 4' -n-pentyl-4-cyanobiphenyl (5CB) were investigated with deuteron nuclear magnetic resonance. The disorder effects of Al2O3 particles on the orientational order of liquid-crystal media and on the field-induced director configuration were studied as a function of alumina density in samples prepared by zero-field cooling and in-field cooling procedures. The order parameters and their variation with alumina density suggest a stronger disordering effect from the nonpolar surface of Alu C 805 particles. For dispersions of hydrophobic Alu C 805 experiments involving in-field cooling from the isotropic phase indicate that the director of “disordered” domains can be aligned, though not perfectly, by the field-aided annealing process. But the same in-field cooling procedure has shown rather limited alignment effects for hydrophilic Alu C/5CB samples. The more robust network of hydrophilic gel possibly coupled with weak liquid-crystal-network interactions could be responsible for the observed behavior. Spectra recorded during in-field cooling and within the isotropic-nematic coexistence region reveal the augmentation of the disorder strength during the transition and illustrate the effect of field-aided annealing. The stability of the aligned states as revealed by deuteron NMR is described. The results are discussed in comparison with previous studies of aerosil dispersions in alkylcyanobiphenyl.

Yim, C. T.

2009-09-01

238

Generation of Radioisotopes with Accelerator Neutrons by Deuterons  

NASA Astrophysics Data System (ADS)

A new system proposed for the generation of radioisotopes with accelerator neutrons by deuterons (GRAND) is described by mainly discussing the production of 99Mo used for nuclear medicine diagnosis. A prototype facility of this system consists of a cyclotron to produce intense accelerator neutrons from the \\text{natC(d,n) reaction with 40 MeV 2 mA deuteron beams, and a sublimation system to separate \\text{99mTc from an irradiated 100MoO3 sample. About 8.1 TBq/week of 99Mo is produced by repeating irradiation on an enriched 100Mo sample (251 g) with accelerator neutrons for two days three times. It meets about 10% of the 99Mo demand in Japan. The characteristic feature of the system lies in its capability to reliably produce a wide variety of high-quality, carrier-free, carrier-added radioisotopes with a minimum level of radioactive waste without using uranium. The system is compact in size, and easy to operate; therefore it could be used worldwide to produce radioisotopes for medical, research, and industrial applications.

Nagai, Yasuki; Hashimoto, Kazuyuki; Hatsukawa, Yuichi; Saeki, Hideya; Motoishi, Shoji; Sato, Nozomi; Kawabata, Masako; Harada, Hideo; Kin, Tadahiro; Tsukada, Kazuaki; Sato, Tetsuya K.; Minato, Futoshi; Iwamoto, Osamu; Iwamoto, Nobuyuki; Seki, Yohji; Yokoyama, Kenji; Shiina, Takehiko; Ohta, Akio; Takeuchi, Nobuhiro; Kawauchi, Yukimasa; Sato, Norihito; Yamabayashi, Hisamichi; Adachi, Yoshitsugu; Kikuchi, Yuji; Mitsumoto, Toshinori; Igarashi, Takashi

2013-06-01

239

On the relativistic field theory model of the deuteron II  

E-print Network

The relativistic field theory model of the deuteron is applied to the calculation of the cross sections of the low-energy radiative neutron-proton capture n + p -> D + gamma and the low-energy two-proton fusion p + p -> D + e^+ + nu_e. For the low-energy radiative neutron-proton capture n + p -> D + gamma our result agrees well with both the experimental data and the potential model prediction. In the case of the two-proton fusion the cross section obtained is 2.9 times as much as that given by the potential approach. The obtained result is discussed in connection with the solar neutrino problem. ERRATUM: We correct the value of the cross section for pp-fusion p + p -> D + e^+ + nu_e. We find a contribution to the astrophysical factor \\delta S_pp(0) = 2.01 x 10^{-25} (1 +/- 0.30) MeV b which is obtained only due to weak and strong low-energy interactions of the protons and the deuteron when neglecting the Coulomb repulsion between protons in the intermediate state. Minor misprints are corrected.

A. N. Ivanov; N. I. Troitskaya; M. Faber; H. Oberhummer

1997-04-15

240

Beam Breakup Studies for New Cryo-Unit  

SciTech Connect

In this paper, we report the numerical simulations of cumulative beam breakup studies for a new cryo-unit for booster design at Jefferson lab. The system consists of two 1-cell and one 7-cell superconducting RF cavities. Combining two 1-cell into a 2-cell together with a 7-cell is also an option. Simulations have been performed using the 2-dimensional time-domain code. The 1-cell+1-cell+7-cell combination confirms beam stability, however, the arrangement 2-cell+7-cell shows instability.

S. Ahmed, I. Shin, R. Kazimi, F. Marhauser ,F. Hannon ,G. Krafft ,B. Yunn ,A. Hofler

2011-03-01

241

Multifragment emission and the experimental characterization of breakup reactions  

SciTech Connect

The production of three or more particles in nuclear reactions is discussed in terms of physically meaningful variables for the description of the asymptotic exit-channel configuration. The emphasis is placed in a direct comparison between these basic variables obtained in a purely experimental way and the corresponding results of generic model calculations. Applications of this approach to a few examples of recent inclusive and exclusive measurements of breakup reactions in the {sup 6,7}Li+{sup 144}Sm systems are presented.

Martinez Heimann, D.; Pacheco, A. J.; Arazi, A.; Fernandez Niello, J. O.; Figueira, J. M.; Negri, A. [Departamento de Fisica-Laboratorio TANDAR, Comision Nacional de Energia Atomica, Av. Gral. Paz 1499, BKNA1650 San Martin (Argentina); CONICET, Av. Rivadavia 1917, C1033AAJ Buenos Aires (Argentina); Capurro, O. A.; Carnelli, P.; Cardona, M. A.; Barbara, E. de; Fimiani, L.; Hojman, D. L.; Marti, G. V. [Departamento de Fisica-Laboratorio TANDAR, Comision Nacional de Energia Atomica, Av. Gral. Paz 1499, BKNA1650 San Martin (Argentina)

2010-08-04

242

Radial electron-beam-breakup transit-time oscillator  

DOEpatents

A radial electron-beam-breakup transit-time oscillator (RBTO) provides a compact high power microwave generator. The RBTO includes a coaxial vacuum transmission line having an outer conductor and an inner conductor. The inner conductor defines an annular cavity with dimensions effective to support an electromagnetic field in a TEM.sub.00m mode. A radial field emission cathode is formed on the outer conductor for providing an electron beam directed toward the annular cavity electrode. Microwave energy is then extracted from the annular cavity electrode.

Kwan, Thomas J. T. (Los Alamos, NM); Mostrom, Michael A. (Albuquerque, NM)

1998-01-01

243

The Breakup of Temperature Inversions In Steep Valleys  

NASA Astrophysics Data System (ADS)

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 lake breeze and a valley wind in the Garda Valley (Northern Italy). Preliminary simulations will be presented. The support of AC by TotalFinaElf and RS by the Physical Meteorology Program of NSF and the VTMX Program of DoE is appreciated.

Colette, A.; Street, R.

244

Mantle thermal history during supercontinent assembly and breakup  

NASA Astrophysics Data System (ADS)

We use mantle convection simulations driven by plate motion boundary conditions to investigate changes in mantle temperature through time. It has been suggested that circum-Pangean subduction prevented convective thermal mixing between sub-continental and sub-oceanic regions. We performed thermo-chemical simulations of mantle convection with velocity boundary conditions based on plate motions for the past 450 Myr using Earth-like Rayleigh number and ~60% internal heating using three different plate motion models for the last 200 Myr [Lithgow-Bertelloni and Richards 1998; Gurnis et al. 2012; Seton et al. 2012; Zhang et al. 2010]. We quantified changes in upper-mantle temperature between 200-1000 km depth beneath continents (defined as the oldest 30% of Earth's surface) and beneath oceans. Sub-continental upper mantle temperature was relatively stable and high between 330 and 220 Ma, coincident with the existence of the supercontinent Pangea. The average sub-continental temperature during this period was, however, only ~10 K greater than during the preceding 100 Myr. In the ~200 Myr since the breakup of Pangea, sub-continental temperatures have decreased only ~15 K in excess of the 0.02 K/Myr secular cooling present in our models. Sub-oceanic upper mantle temperatures did not vary more than 5 K between 400 and 200 Ma and the cooling trend following Pangea breakup is less pronounced. Recent geochemical observations imply rapid upper mantle cooling of O(10^2) K during continental breakup; our models do not produce warming of this magnitude beneath Pangea or cooling of similar magnitude associated with the breakup of Pangea. Our models differ from those that produce strong sub-continental heating in that the circum-Pangean subduction curtain does not completely inhibit mixing between the sub-continental and sub-oceanic regions and we include significant internal heating, which limits the rate of temperature increase. Heat transport in our simulations is controlled to first order by plate motions. Most of the temporal variability in surface heat flow is driven by variations in seafloor spreading rate and the accompanying changes in slab velocities dominate variations in buoyancy flux at all mantle depths. Variations in plume buoyancy flux are small but are correlated with the slab buoyancy flux variations.

Rudolph, M. L.; Zhong, S.

2013-12-01

245

Temperature dependence of droplet breakup in 8CB and 5CB liquid crystals  

NASA Astrophysics Data System (ADS)

Droplet breakup of many Newtonian fluids is well described by current experiments, theory, and simulations. Breakup in complex fluids where interactions between mesoscopic structural features can affect the flows remains poorly understood and a burgeoning area of research. Here, we report on our investigations of droplet breakup in thermotropic liquid crystals. We investigate breakup in the smectic, nematic, and isotropic phases of 4-cyano 4-octylbiphenyl (8CB) and the nematic and isotropic phases of 4-cyano 4-pentylbiphenyl (5CB). The experiment consists of varying the ambient temperature to control liquid crystalline phase and imaging breakup using a fast video camera at up to 110000 frames/s. We expand on previous work [John R. Savage , Soft Matter1744-683X10.1039/b923069f 6, 892 (2010)] that shows breakup in the smectic phase is symmetric, producing no satellite droplets, and is well described by a similarity solution for a shear-thinning power-law fluid. We show that in the nematic phase the breakup occurs in two stages. In the first stage, the breakup is symmetric and the power-law exponent for the minimum radius dependence on the time left to breakup is 1.2breakup dynamics. Finally, in the isotropic phase, the exponents are consistent with theoretical predictions and experiments for Newtonian fluid breakup in the inertial viscous regime.

Porter, Daniel; Savage, John R.; Cohen, Itai; Spicer, Patrick; Caggioni, Marco

2012-04-01

246

Numerical simulation of breakup of a viscous drop in simple shear flow through a volume-of-fluid method  

NASA Astrophysics Data System (ADS)

A spherical drop, placed in a second liquid of the same density, is subjected to shearing between parallel plates. The subsequent flow is investigated numerically with a volume-of-fluid (VOF) method. The scheme incorporates a semi-implicit Stokes solver to enable computations at low Reynolds number. Our simulations compare well with previous theoretical, numerical, and experimental results. For capillary numbers greater than the critical value, the drop deforms to a dumbbell shape and daughter drops detach via an end-pinching mechanism. The number of daughter drops increases with the capillary number. The breakup can also be initiated by increasing the Reynolds number.

Li, Jie; Renardy, Yuriko Y.; Renardy, Michael

2000-02-01

247

Asymptotic behavior of the deuteron form factors in the two-nucleon model and electron scattering experiments at GeV energies at JLab  

SciTech Connect

Using the instant form dynamics of Poincare invariant quantum mechanics and the modified relativistic impulse approximation proposed previously, we calculate asymptotic behavior of electromagnetic form factors for the deuteron considered as a two-nucleon system. We show that today, experimentation on elastic ed scattering has reached the asymptotic regime. We also estimate the possible range of momentum transfer in which the quark degrees of freedom will possibly be seen in future JLab experiments. The explicit relation between the behavior of the deuteron wave function at r=0 and the form factors asymptotic behavior is obtained, and the conditions of wave functions that give the asymptotic behavior predicted by QCD and quark counting rules are formulated.

Krutov, A. F.; Tsirova, N. A. [Samara State University, RU-443011 Samara (Russian Federation); Troitsky, V. E. [D. V. Skobeltsyn Institute of Nuclear Physics, Moscow State University, RU-119992 Moscow (Russian Federation)

2008-10-15

248

Effects of Spring Breakup on Microscale Air Temperatures in the Mackenzie River Delta  

Microsoft Academic Search

The effects of spring breakup on microscale air temperatures in the Mackenzie River delta were investigated by means of intervention analysis. Small but statistically significant increases in temperatures were detected for some areas within the delta and appeared to be related to ice breakup events in nearby channels and lake systems. The magnitude of the temperature increase appeared to be

STANLEY M. HIRST

1984-01-01

249

Satellites in the inviscid breakup of bubbles J.M. Gordillo  

E-print Network

Satellites in the inviscid breakup of bubbles J.M. Gordillo Departamento de Ingenier the essential role played by gas inertia in the breakup of gas bubbles. Our results reveal that, whenever the gas to liquid density ratio = g/l is different from zero, tiny satellite bubbles may be formed

Fontelos, Marco

250

Analyzing the tradeoffs between breakup and cloning in the context of organizational self-design  

E-print Network

Cite as: Analyzing the tradeoffs between breakup and cloning in the con- text of organizational selfAnalyzing the tradeoffs between breakup and cloning in the context of organizational self-problems and assigning one of the sub-problems to the newly spawned agent. An alternative approach works by "cloning

Allan, Vicki H.

251

Buoyancy-driven motion and breakup of viscous drops in constricted capillaries  

E-print Network

Buoyancy-driven motion and breakup of viscous drops in constricted capillaries Ufuk Olgac, Arif D Buoyancy-driven motion and breakup of viscous drops in sinusoidally constricted channels are studied of geometrical parameters and Bond numbers. Ã? 2006 Elsevier Ltd. All rights reserved. Keywords: Buoyancy

Muradoglu, Metin

252

Analysis of strong acoustic excitation on the breakup and dispersion of a liquid jet  

Microsoft Academic Search

The effect of strong acoustic waves on the breakup and dispersion of cylindrical liquid jets is considered with regard to combustion instabilities of liquid injection burners. An experimental study showed that a strong acoustic excitation modifies jet stability at low injection velocities (by reduction of the breakup length). This phenomenon, which exhibits saturation and threshold effects, is especially sensitive to

Bernard Labegorre

1993-01-01

253

Break-up channels in muon capture on 3He  

E-print Network

The mu + 2H -> nu + n + n, mu + 3He -> nu + 3H, mu + 3He -> nu + n + d and mu + 3He -> nu + n + n + p capture reactions are studied with various realistic potentials under full inclusion of final state interactions. Our results for the two- and three-body break-up of 3He are calculated with a variety of nucleon-nucleon potentials, among which is the AV18 potential, augmented by the Urbana~IX three-nucleon potential. Most of our results are based on the single nucleon weak current operator. As a first step, we have tested our calculation in the case of the mu + 2H -> nu + n + n and mu + 3He -> nu + 3H reactions, for which theoretical predictions obtained in a comparable framework are available. Additionally, we have been able to obtain for the first time a realistic estimate for the total rates of the muon capture reactions on 3He in the break-up channels: 544 1/s and 154 1/s for the n + d and n + n + p channels, respectively. Our results have also been compared with the most recent experimental data, finding a rough agreement for the total capture rates, but failing to reproduce the differential capture rates.

J. Golak; R. Skibinski; H. Wita?a; K. Topolnicki; A. E. Elmeshneb; H. Kamada; A. Nogga; L. E. Marcucci

2014-06-26

254

Coalescence and breakup between a capillary switch and a droplet  

NASA Astrophysics Data System (ADS)

A capillary switch can be formed by overfilling a circular orifice in a plate with liquid, where the contact line is pinned at the rim by using a non-wetting substrate. For surface tension to be the dominant force in the system, the size of the hole has to be smaller than the capillary length (about a millimeter for water). Application of capillary switches has already been demonstrated in optics through a fast-acting adaptive lens. Here, we investigate how capillary switches can be used to detach a small packet of liquid from a substrate and subsequently reattach it elsewhere without the use of any moving parts. Overcoming the inherent adhesion force between the liquid packet and its substrate is the challenge. Experiments have been conducted on the coalescence and subsequent breakup of a switch and a droplet (pendant or sessile) which encapsulates the liquid packet. The coalescence and break-up processes are also analyzed computationally using finite element analysis and the predictions are compared with the experimental measurements.

Hirsa, A.; Martinovic, I.; Lopez, C.; Basaran, O.; Ramalingam, S.

2007-11-01

255

Break-up of New Orleans Households after Hurricane Katrina  

PubMed Central

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 break-up due to Hurricane Katrina by comparing a probability sample of pre-Katrina New Orleans resident adult household heads and non–household heads (N = 242), traced just over a year later, with a matched sample from a nationally representative survey over an equivalent period. One in three among all adult non–household heads, and one in two among adult children of household heads, had separated from the household head 1 year post-Katrina. These rates were, respectively, 2.2 and 2.7 times higher than national rates. A 50% higher prevalence of adult children living with parents in pre-Katrina New Orleans than nationally increased the hurricane’s impact on household break-up. Attention to living arrangements as a dimension of social vulnerability in disaster recovery is suggested. PMID:21709733

Rendall, Michael S.

2011-01-01

256

Break-up channels in muon capture on He3  

NASA Astrophysics Data System (ADS)

The ?-+2H???+n+n, ?-+3He???+3H, ?-+3He???+n+d, and ?-+3He???+n+n+p capture reactions are studied with various realistic potentials under full inclusion of final-state interactions. Our results for the two- and three-body break-up of He3 are calculated with a variety of nucleon-nucleon potentials, among which is the AV18 potential, augmented by the Urbana IX three-nucleon potential. Most of our results are based on the single-nucleon weak-current operator. As a first step, we tested our calculation in the case of the ?-+2H???+n+n and ?-+3He???+3H reactions, for which theoretical predictions obtained in a comparable framework are available. Additionally, we have been able to obtain for the first time a realistic estimate for the total rates of the muon capture reactions on He3 in the break-up channels: 544 s-1 and 154 s-1 for the n +d and n +n+p channels, respectively. Our results are compared with the most recent experimental data, finding a rough agreement for the total capture rates, but failing to reproduce the differential capture rates.

Golak, J.; Skibi?ski, R.; Wita?a, H.; Topolnicki, K.; Elmeshneb, A. E.; Kamada, H.; Nogga, A.; Marcucci, L. E.

2014-08-01

257

Break-up of New Orleans Households after Hurricane Katrina.  

PubMed

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 break-up due to Hurricane Katrina by comparing a probability sample of pre-Katrina New Orleans resident adult household heads and non-household heads (N = 242), traced just over a year later, with a matched sample from a nationally representative survey over an equivalent period. One in three among all adult non-household heads, and one in two among adult children of household heads, had separated from the household head 1 year post-Katrina. These rates were, respectively, 2.2 and 2.7 times higher than national rates. A 50% higher prevalence of adult children living with parents in pre-Katrina New Orleans than nationally increased the hurricane's impact on household break-up. Attention to living arrangements as a dimension of social vulnerability in disaster recovery is suggested. PMID:21709733

Rendall, Michael S

2011-06-01

258

Deformation and breakup of viscoelastic droplets in confined shear flow.  

PubMed

The deformation and breakup of Newtonian and viscoelastic droplets are studied in confined shear flow. Our numerical approach is based on a combination of lattice-Boltzmann models and finite difference schemes, the former used to model two immiscible fluids with variable viscosity ratio and the latter used to model the polymer dynamics. The kinetics of the polymers is introduced using constitutive equations for viscoelastic fluids with finitely extensible nonlinear elastic dumbbells with Peterlin's closure. We quantify the droplet response by changing the polymer relaxation time ?_{P}, the maximum extensibility L of the polymers, and the degree of confinement, i.e., the ratio of the droplet diameter to wall separation. In unconfined shear flow, the effects of droplet viscoelasticity on the critical capillary number Ca_{cr} for breakup are moderate in all cases studied. However, in confined conditions a different behavior is observed: The critical capillary number of a viscoelastic droplet increases or decreases, depending on the maximum elongation of the polymers, the latter affecting the extensional viscosity of the polymeric solution. Force balance is monitored in the numerical simulations to validate the physical picture. PMID:25215849

Gupta, A; Sbragaglia, M

2014-08-01

259

Deformation and breakup of viscoelastic droplets in confined shear flow  

NASA Astrophysics Data System (ADS)

The deformation and breakup of Newtonian and viscoelastic droplets are studied in confined shear flow. Our numerical approach is based on a combination of lattice-Boltzmann models and finite difference schemes, the former used to model two immiscible fluids with variable viscosity ratio and the latter used to model the polymer dynamics. The kinetics of the polymers is introduced using constitutive equations for viscoelastic fluids with finitely extensible nonlinear elastic dumbbells with Peterlin's closure. We quantify the droplet response by changing the polymer relaxation time ?P, the maximum extensibility L of the polymers, and the degree of confinement, i.e., the ratio of the droplet diameter to wall separation. In unconfined shear flow, the effects of droplet viscoelasticity on the critical capillary number Cacr for breakup are moderate in all cases studied. However, in confined conditions a different behavior is observed: The critical capillary number of a viscoelastic droplet increases or decreases, depending on the maximum elongation of the polymers, the latter affecting the extensional viscosity of the polymeric solution. Force balance is monitored in the numerical simulations to validate the physical picture.

Gupta, A.; Sbragaglia, M.

2014-08-01

260

Effect of the breakup context on unwanted pursuit behavior perpetration between former partners.  

PubMed

Former partners comprise the most important subgroup of stalkers. However, contextual factors related to the breakup are hardly examined to explain ex-partner pursuit. In a community sample of 194 separated persons, about one-fifth perpetrated at least one unwanted pursuit behavior in the past 2 weeks. Being female, lowly educated, and socially undesirable raised the number of perpetrated behaviors. Beyond these effects, the number of behaviors increased when the cause of the break was attributed to the ex-partner or external factors and when the ex was appraised as the breakup initiator. Breakup reasons, the ex-partner's lack in meeting family obligations and own infidelity, also related to pursuit behaviors albeit inferior to subjective attributions and appraisals of initiation. Finally, participants who felt more anxious or lonely negative showed more behaviors. The results enlighten that the breakup context gains further attention. Clinical treatment might benefit from fostering cognitive reconstructions and breakup adjustment. PMID:21470223

De Smet, Olivia; Buysse, Ann; Brondeel, Ruben

2011-07-01

261

Extracting the electric dipole breakup cross section of one-neutron halo nuclei from inclusive breakup observables  

NASA Astrophysics Data System (ADS)

We discuss how to extract an electric dipole (E1) breakup cross section ? ({E1}) from one-neutron removal cross sections measured at 250 MeV/nucleon by using {}^{12}C and {}^{208}Pb targets, ? _{-1n}C and ? _{-1n}^{Pb}, respectively. It is shown that, within about 5% error, ? ({E1}) can be obtained by subtracting ? ? _{-1n}C from ? _{-1n}^{Pb}, as assumed in preceding studies. However, for the reaction of weakly bound projectiles, the scaling factor ? is found to be about twice as large as that usually adopted. As a result, we obtain a 13-20% smaller ? ({E1}) of {}^{31}Ne at 250 MeV/nucleon than extracted in a previous analysis of experimental data. By compiling the values of ? obtained for several projectiles, ? =(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.

Yoshida, Kazuki; Fukui, Tokuro; Minomo, Kosho; Ogata, Kazuyuki

2014-05-01

262

Neutron Polarizabilities From Compton Scattering on the Deuteron?  

E-print Network

A calculation of deuteron Compton scattering using non-relativistic perturbation theory is presented,with the primary motivation of investigating the feasibility of determining the neutron polarizabilities from this type of experiment. This calculation is expected to be valid for energies below 100 MeV. Pion-exchange, relativistic, and recoil corrections are also included. The low-energy theorem for gauge invariance is shown to be satisfied. The relative effects of the different terms and their effects on the determinations of the polarizabilities are discussed at energies of 49, 69, and 95 MeV. The cross-section is dominated by the seagull, polarizability, and electromagnetic multipole interactions. Relativistic and pion-exchange terms are also important, while recoil corrections and multipoles of $L$=2 and greater are negligible. The calculation provides a reasonable description of the experimental data points at 49 and 69 MeV. The polarizabilities are difficult to determine at these energies. A more accura...

Karakowski, J J; Karakowski, Jonathan J.; Miller, Gerald A.

1999-01-01

263

Photoproduction of Theta+ on the nucleon and deuteron  

E-print Network

Photoproduction of the pentaquark particle Theta^+ on the nucleon has been studied by using an isobar and a Regge model. Using the isobar model, total cross sections around 100 nb for the gamma n --> K- Theta+ channel and 400 nb for the gamma p --> {\\bar K}0 Theta+ process are obtained. The inclusion of the K* intermediate state yields a substantially large effect, especially in the gamma p --> {\\bar K}0 Theta+ process. The Regge approach predicts smaller cross sections, i.e., less than 100 nb (20 nb) for the process on the neutron (proton). By using an elementary operator from the isobar model, cross sections for the process on a deuteron are predicted.

T. Mart; A. Salam; K. Miyagawa; C. Bennhold

2004-12-24

264

Operator Evolution via the Similarity Renormalization Group I: The Deuteron  

E-print Network

Similarity Renormalization Group (SRG) flow equations can be used to unitarily soften nuclear Hamiltonians by decoupling high-energy intermediate state contributions to low-energy observables while maintaining the natural hierarchy of many-body forces. Analogous flow equations can be used to consistently evolve operators so that observables are unchanged if no approximations are made. The question in practice is whether the advantages of a softer Hamiltonian and less correlated wave functions might be offset by complications in approximating and applying other operators. Here we examine the properties of SRG-evolved operators, focusing in this paper on applications to the deuteron but leading toward methods for few-body systems. We find the advantageous features generally carry over to other operators with additional simplifications in some cases from factorization of the unitary transformation operator.

E. R. Anderson; S. K. Bogner; R. J. Furnstahl; R. J. Perry

2010-08-09

265

Nonradiative proton--deuteron fusion in stellar plasma  

E-print Network

The nuclear reaction e+p+d -----> He3 + e is considered at thermonuclear energies. The motion of the electron is treated within the adiabatic approximation and the pd scattering state is constructed in the form of an antisymmetrized product of the bound state wave function of the deuteron and of the wave function of the pd relative motion. The latter is calculated using an effective pd potential constructed via the Marchenko inverse scattering method. The bound state wave function of He3 is obtained using Faddeev--type integrodifferential equations. The reaction rate thus obtained for the solar interior conditions is approximately 10^{-4} of the corresponding rate for the radiative capture pd ----> He3 + gamma .

S. A. Rakityansky; S. A. Sofianos; L. L. Howell; M. Braun; V. B. Belyaev

1996-07-16

266

Meson Photoproduction off the Deuteron and off {sup 3}He  

SciTech Connect

Photoproduction of mesons off the deuteron and He nuclei has been studied at the tagged photon facilities of the Bonn ELSA accelerator and the Mainz MAMI accelerator with the Crystal/ setup (Mainz). Meson photoproduction off the neutron has been investigated for different final states ({pi}{sup o}, {pi}{sup o} {pi}{sup o}, {pi}{sup o} {pi}{sup -}, {eta}, {eta}{sup '}, {eta}{pi}{sup o}). A surprising finding was a narrow structure in the {gamma}n{yields}n{eta} excitation function, which is not seen in the proton case. Photoproduction off {sup 3}He has provided further evidence for the formation of an h-mesic state.

Krusche, B. [Department of Physics, University of Basel, Klingelbergstrasse. 82 Basel (Switzerland)

2010-08-05

267

Measurement of the fluence response of the GSI neutron ball in high-energy neutron fields produced by 500 AMeV and 800 AMeV deuterons.  

PubMed

Experiments were performed in Cave C of GSI (Gesellschaft für Schwerionenforschung) using the LAND (Large Area Neutron Detector) in combination with the deflection magnet ALADIN (A LArge DIpol magNet) in front of the LAND where charged particles and neutrons can be separated. This arrangement is used to create high-energetic neutron fields by irradiation of a thick lead target (5 cm) with deuteron beams with the energies of 500 or 800 MeV per nucleon. In break-up reactions the neutron is separated from the proton which is deflected in the magnetic field of the ALADIN. The produced neutron radiation, which has a pronounced peak at the nucleon energy, is used to measure the fluence response of the GSI neutron ball. A thermoluminescence (TL) based spherical neutron dosemeter was developed for the area monitoring for the quantity H(10) at high-energy accelerators. In the same experiment, the spectral neutron fluence Phi(E) is measured with the LAND in the energy range from 100 MeV to 1 GeV. The measured fluence responses are compared with results of FLUKA calculations and the corresponding fluence-to-dose conversion coefficients. The measured dosemeter responses are too high in comparison to the calculated ones (up to approximately 50%), the dosemeter reading gives dose values which are too high by a factor of 1.1-2.2 related to the corresponding fluence-to-dose conversion factors. PMID:17519242

Fehrenbacher, G; Gutermuth, F; Kozlova, E; Radon, T; Aumann, T; Beceiro, S; Le Bleis, T; Boretzky, K; Emling, H; Johansson, H; Kiselev, O; Simon, H; Typel, S

2007-01-01

268

Breakup and early seafloor spreading between India and Antarctica  

NASA Astrophysics Data System (ADS)

We present a tectonic interpretation of the breakup and early seafloor spreading between India and Antarctica based on improved coverage of potential field and seismic data off the east Antarctic margin between the Gunnerus Ridge and the Bruce Rise. We have identified a series of ENE trending Mesozoic magnetic anomalies from chron M9o (~130.2 Ma) to M2o (~124.1 Ma) in the Enderby Basin, and M9o to M4o (~126.7 Ma) in the Princess Elizabeth Trough and Davis Sea Basin, indicating that India-Antarctica and India-Australia breakups were roughly contemporaneous. We present evidence for an abandoned spreading centre south of the Elan Bank microcontinent; the estimated timing of its extinction corresponds to the early surface expression of the Kerguelen Plume at the Southern Kerguelen Plateau around 120 Ma. We observe an increase in spreading rate from west to east, between chron M9 and M4 (38-54 mm yr-1), along the Antarctic margin and suggest the tectono-magmatic segmentation of oceanic crust has been influenced by inherited crustal structure, the kinematics of Gondwanaland breakup and the proximity to the Kerguelen hotspot. A high-amplitude, E-W oriented magnetic lineation named the Mac Robertson Coast Anomaly (MCA), coinciding with a landwards step-down in basement observed in seismic reflection data, is tentatively interpreted as the boundary between continental/transitional zone and oceanic crust. The exposure of lower crustal rocks along the coast suggests that this margin formed in a metamorphic core complex extension mode with a high strength ratio between upper and lower crust, which typically occurs above anomalously hot mantle. Together with the existence of the MCA zone this observation suggests that a mantle temperature anomaly predated the early surface outpouring/steady state magmatic production of the Kerguelen LIP. An alternative model suggests that the northward ridge jump was limited to the Elan Bank region, whereas seafloor spreading continued in the West Enderby Basin and its Sri Lankan conjugate margin. In this case, the MCA magnetic anomaly could be interpreted as the southern arm of a ridge propagator that stopped around 120 Ma.

Gaina, Carmen; Müller, R. Dietmar; Brown, Belinda; Ishihara, Takemi; Ivanov, Sergey

2007-07-01

269

Rifting and breakup in the South China Sea  

NASA Astrophysics Data System (ADS)

The magma-poor or intermediate magmatic South China Sea is a natural laboratory for studying rifting and breakup. The basin shows an irregular triangular shape with a SW pointing apex, which manifests a preceding propagating rift. The earliest phase of rifting started in the Early Paleocene when a Mesozoic convergent margin changed to extension. After about 30 Million years of rifting, breakup in the major eastern subbasin of the SCS occurred in the Early Oligocene but rifting continued and subsequent breakup of the southwest subbasin took place in the Late Oligocene. The wide Early Cenozoic South China Sea rift preserves the initial rift architecture at the distal margins. Seismic reflection data imaging conjugate crustal sections at the South China Sea margins result in a conceptual model for rift-evolution at conjugate magma-poor margins in time and space. Most distinct are regular undulations in the crust-mantle boundary. Individual rift basins are bounded to crustal blocks by listric normal faults on either side. Moho uplifts are distinct beneath major rift basins, while the Moho is downbended beneath crustal blocks, with a wavelength of undulations in the crust-mantle boundary that approximately equals the thickness of the continental crust. Most of the basin-bounding faults sole out within the middle crust. At the distal margins, detachment faults are located at a mid-crustal level where a weak zone decouples crust and mantle lithosphere during rifting. The lower crust in contrast is interpreted as being strong. Only in the region within about 50 km from the continent-ocean transition (COT) we suggest that normal faults reach the mantle, enabling potentially a coupling between the crust and the mantle. Here, at the proximal margins detachment fault dip either seaward or landward. This may indicate the presence of exhumed mantle bordering the continental margins. Post-rift shallow-water platform carbonates indicate a delay in subsidence during rifting in the South China Sea. We propose that this is an inherent process in highly-extended continental margins and a common origin may be the influx of warm asthenospheric material into initially cool sub-lithospheric mantle. On a crustal-scale largely symmetric process predominate in the initial rifting stage. At the future COT either of the rift basin bounding faults subsequently penetrates the entire crust, resulting in asymmetry at this location. However, asymmetric deformation which is controlled by large scale detachment faulting is confined to narrow areas and does not result in a margin-wide simple-shear model. Rather considerable along-margin variations are suggested resulting in alternating "upper and lower plate" margins.

Franke, Dieter; Savva, Dimitri; Pubellier, Manuel; Steuer, Stephan; Mouly, Benoit; Auxietre, Jean-Luc; Meresse, Florian; Chamot-Rooke, Nicolas

2014-05-01

270

Deuteron and Oxygen-17 NMR Studies of Molecular Motion in Methanol-Saturated Nafion Membranes.  

National Technical Information Service (NTIS)

Deuteron and oxygen-17 NMR linewidth and spin-lattice relaxation measurements in Nafion-117 films containing methanol at -75% and -100% saturation are reported. Molecular motion probed by room temperature measurements in stretched films and low T measurem...

R. S. Chen, J. R. Jayakody, S. G. Greenbaum

1993-01-01

271

Quark-Model Nucleon-Nucleon Interaction Applied to Nucleon-Deuteron Scattering  

NASA Astrophysics Data System (ADS)

We have examined the neutron-deuteron low-energy effective-range parameters, differential cross sections and spin polarization observables of the elastic nucleon-deuteron scattering up to the incident nucleon energy E N = 65 MeV, using the quark-model nucleon-nucleon interaction fss2. These observables are consistently described without introducing three nucleon forces except for the nucleon analyzing power A y ( ?) and the deuteron vector analyzing power iT 11( ?) in the low-energy region E N ? 25 MeV. The long-standing A y puzzle is slightly improved, but still remains. We have incorporated the screened Coulomb force to the proton-deuteron scattering, modifying the Vincent-Phatak approach for the sharp cutoff Coulomb force. The Coulomb effect on the elastic scattering observables is discussed.

Fukukawa, Kenji; Fujiwara, Yoshikazu

2013-03-01

272

Inadvertent Earth Reentry Breakup Analysis for the New Horizons Mission  

NASA Technical Reports Server (NTRS)

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.

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

2007-01-01

273

Breakup of a homeobox cluster after genome duplication in teleosts.  

PubMed

Several families of homeobox genes are arranged in genomic clusters in metazoan genomes, including the Hox, ParaHox, NK, Rhox, and Iroquois gene clusters. The selective pressures responsible for maintenance of these gene clusters are poorly understood. The ParaHox gene cluster is evolutionarily conserved between amphioxus and human but is fragmented in teleost fishes. We show that two basal ray-finned fish, Polypterus and Amia, each possess an intact ParaHox cluster; this implies that the selective pressure maintaining clustering was lost after whole-genome duplication in teleosts. Cluster breakup is because of gene loss, not transposition or inversion, and the total number of ParaHox genes is the same in teleosts, human, mouse, and frog. We propose that this homeobox gene cluster is held together in chordates by the existence of interdigitated control regions that could be separated after locus duplication in the teleost fish. PMID:16801555

Mulley, John F; Chiu, Chi-hua; Holland, Peter W H

2006-07-01

274

Inferences Concerning the Magnetospheric Source Region for Auroral Breakup  

NASA Technical Reports Server (NTRS)

It is argued that the magnetospheric source region for auroral arc breakup and substorm initiation is along boundary plasma sheet (BPS) magnetic field lines. This source region lies beyond a distinct central plasma sheet (CPS) region and sufficiently far from the Earth that energetic ion motion violates the guiding center approximation (i.e., is chaotic). The source region is not constrained to any particular range of distances from the Earth, and substorm initiation may be possible over a wide range of distances from near synchronous orbit to the distant tail. It is also argued that the layer of low-energy electrons and velocity dispersed ion beams observed at low altitudes on Aureol 3 is not a different region from the region of auroral arcs. Both comprise the BPS. The two regions occasionally appear distinct at low altitudes because of the effects of arc field-aligned potential drops on precipitating particles.

Lyons, L. R.

1992-01-01

275

Large eddy breakup devices as low Reynolds number airfoils  

NASA Technical Reports Server (NTRS)

Turbulent drag reduction downstream of large-eddy breakup (LEBU) devices is analyzed from the viewpoint of low-Reynolds number airfoil aerodynamics. It is argued that the variability of results between different research labs is primarily due to low Reynolds number 'phenomena' associated with unsteady separation/transition of the LEBU device boundary layer. LEBU drag reduction is shown to be an extremely sensitive function of device microgeometry at the low Reynolds numbers of all current investigations, and by analogy with conventional low-Reynolds number airfoil testing, the conclusion is drawn that the full potential for LEBU drag reduction must be explored at chord Reynolds numbers of 300,000 and above.

Anders, John B.

1986-01-01

276

Non-axisymmetric breakup of a liquid jet during atomization  

SciTech Connect

The existing aerodynamic theory is not capable of predicting the phenomenon of nonaxisymmetric breakup of a liquid jet, which has long been observed in experiments. A dispersion equation which accounts for the growth of asymmetric waves is derived in this paper. It is demonstrated that there exists a critical Weber number, below which the growth of the nonaxisymmetric disturbance becomes dominant. The present theory indicates the domination of sinuous wave and the possible formation of curling flat sheet from an axisymmetric jet. According to the present analysis, for a highspeed jet, it is the drops, instead of rings as predicted by the theory based on the axisymmetric assumption, that breakaway from the jet surface. 30 refs.

Yang, H.Q. (CFD Research Corp., Huntsville, AL (USA))

1991-01-01

277

Obstructed Breakup of Slender Drops in a Microfluidic T Junction  

NASA Astrophysics Data System (ADS)

In this Letter we present a theoretical analysis of the droplet breakup with “permanent obstruction” in a microfluidic T junction [M.-C. Jullien et al., Phys. FluidsPHFLE61070-6631 21, 072001 (2009)10.1063/1.3170983]. The proposed theory is based on a simple geometric construction for the interface shape combined with Tanner’s law for the local contact angle. The resulting scaling of the droplet deformation with time and capillary number is in excellent agreement with the results of direct numerical simulations and prior experiments. More rigorous analysis based on the lubrication approximation reveals a self-similar behavior analogous to the classical problem of a droplet spreading over a preexisting liquid film.

Leshansky, A. M.; Afkhami, S.; Jullien, M.-C.; Tabeling, P.

2012-06-01

278

Airfoil large eddy breakup devices for turbulent drag reduction  

NASA Technical Reports Server (NTRS)

It was determined from the present LaRC experiments that tandem, airfoil-shaped large eddy breakup (LEBU) devices can reduce local skin friction as much as 30 percent with a recovery region extending more than 100 boundary layer thicknesses downstream. These airfoils experience near laminar skin friction device drag and produce net drag reductions of up to 7 percent. In contrast to the thin plates used in previous experiments, these airfoils are more than 1000 time stiffer and hence have the potential to withstand the real flight environment (dynamic pressure 36 times larger than in low-speed wing tunnels). In addition, the higher Reynolds numbers of the present tests indicate drag reduction performance is at least as good (or better) as at lower Reynolds numbers.

Anders, J. B.

1986-01-01

279

Neutron-deuteron elastic scattering from 6 to 12.5 GeV\\/c  

Microsoft Academic Search

The differential cross section for neutron-deuteron elastic scattering was measured for four-momentum transfers 0.3 < -t < 2.0 (GeV\\/c)2 with incident neutron momenta between 6 and 12.5 GeV\\/c. The measurement was made with spark chambers at the Argonne ZGS. Results are compared with proton-deuteron elastic scattering at comparable energies as a test of isospin invariance in strong interactions and with

J. P. Chanowski; H. R. Gustafson; M. J. Longo; J. L. Stone

1976-01-01

280

Dynamic disorder in 2,3-dimethylnaphthalene: a single crystal deuteron nuclear magnetic resonance study  

Microsoft Academic Search

Deuteron NMR experiments on single crystals of 2,3-dimethylnaphthalene (DMN) deuterated in the aromatic sites are reported. The deuteron resonances are inhomogeneously broadened and their widths are strongly anisotropic. This is shown to be due to orientational disorder of the DMN molecules. Two types of disorder are distinguished: polar disorder, also seen by X-ray and neutron diffraction, in which the direction

P. Speier; H. ZIMMERMANN; U. HAEBERLEN; Z. LUZ

1998-01-01

281

X-Ray Study of Deuteron-Irradiated Copper near 10°K  

Microsoft Academic Search

Precise measurements of lattice expansion of high-purity copper held near 10°K during deuteron bombardment were made using a rotating single-crystal method. An expansion of (4.1+\\/-0.2)×10-21 per 7-Mev deuteron\\/cm2 was found. No broadening of the Laue-Bragg intensity around the (4,0,0) reciprocal lattice point occurred. These effects are broadly consistent with the introduction of small point centers of dilatation. On the assumption

R. O. Simmons; R. W. Balluffi

1958-01-01

282

X-Ray Study of Deuteron-Irradiated Copper near 10°K  

Microsoft Academic Search

Precise measurements of lattice expansion of high-purity copper held near 10°K during deuteron bombardment were made using a rotating single-crystal method. An expansion of (4.1+\\/-0.2) ×10-21 per 7-Mev deuteron\\/cm2 was found. No broadening of the Laue-Bragg intensity around the (4,0,0) reciprocal lattice point occurred. These effects are broadly consistent with the introduction of small point centers of dilatation. On the

R. O. Simmons; R. W. Balluffi

1958-01-01

283

The asymptotic S-state amplitude and the root mean square radius of the deuteron  

Microsoft Academic Search

The values of the root mean square radius of the deuteron (rD) given by Berard et al. (1973), Allen et al. (1981) and Simon et al. (1980, 1981) are compared. Model calculations suggest that the elastic electron-deuteron scattering data of Akimov et al. (1979) are not in the most suitable region to extract a useful value for rD. The method

J P McTavish

1982-01-01

284

Correlating early evolution of parasitic platyhelminths to Gondwana breakup.  

PubMed

Investigating patterns and processes of parasite diversification over ancient geological periods should involve comparisons of host and parasite phylogenies in a biogeographic context. It has been shown previously that the geographical distribution of host-specific parasites of sarcopterygians was guided, from Palaeozoic to Cainozoic times, mostly by evolution and diversification of their freshwater hosts. Here, we propose phylogenies of neobatrachian frogs and their specific parasites (Platyhelminthes, Monogenea) to investigate coevolutionary processes and historical biogeography of polystomes and further discuss all the possible assumptions that may account for the early evolution of these parasites. Phylogenetic analyses of concatenated rRNA nuclear genes (18S and partial 28S) supplemented by cophylogenetic and biogeographic vicariance analyses reveal four main parasite lineages that can be ascribed to centers of diversity, namely Australia, India, Africa, and South America. In addition, the relationships among these biogeographical monophyletic groups, substantiated by molecular dating, reflect sequential origins during the breakup of Gondwana. The Australian polystome lineage may have been isolated during the first stages of the breakup, whereas the Indian lineage would have arisen after the complete separation of western and eastern Gondwanan components. Next, polystomes would have codiverged with hyloid sensu stricto and ranoid frog lineages before the completion of South American and African plate separation. Ultimately, they would have undergone an extensive diversification in South America when their ancestral host families diversified. Therefore, the presence of polystome parasites in specific anuran host clades and in discrete geographic areas reveals the importance of biogeographic vicariance in diversification processes and supports the occurrence and radiation of amphibians over ancient and recent geological periods. PMID:21856629

Badets, Mathieu; Whittington, Ian; Lalubin, Fabrice; Allienne, Jean-Francois; Maspimby, Jean-Luc; Bentz, Sophie; Du Preez, Louis H; Barton, Diane; Hasegawa, Hideo; Tandon, Veena; Imkongwapang, Rangpenyuba; Imkongwapang, Rangpenyubai; Ohler, Annemarie; Combes, Claude; Verneau, Olivier

2011-12-01

285

P/2010 A2 - Impact or rotational break-up?  

NASA Astrophysics Data System (ADS)

The active asteroid P/2010 A2 was discovered in January 2010 by the LINEAR Sky Survey. It displayed a long, narrow dust tail, but has the orbit of an inner Main Belt asteroid. High resolution imaging with the Hubble Space Telescope (HST) showed that the dust in the tail seemed to emerge from a bright crossshaped pattern of large dust grains rather than directly from the main nucleus, which appeared almost detached from the tail. Dynamical analysis of the tail's position angle on the sky revealed that the dust was emitted from the nucleus during a very short time span about nine months before the discovery of P/2010 A2 [1, 2]. We therefore proposed that in February or March 2009, P/2010 A2 either was impacted by a second asteroid or disrupted due to rotational break-up. Figure 1: Asteroid P2010/A2 on 29 January 2010 seen with the HST WFC3/UVIS. Here, we analyse the orbital paths of the tail structures at the head of the dust tail of P/2010 A2. We follow the positions of individual features over a series of HST images taken over several months in 2010. We simulate the trajectories of test particles emitted from the main nucleus in February or March 2009 to all directions, with variable speeds and radiation pressure parameters. We compare the trajectory of each test particle to the trajectories of the observed features, and in this way constrain the emission velocity and radiation pressure parameter (equivalent to size) of the grains forming the cross-shaped structure. We find that this region contains centimetre- to metre-sized particles ejected at speeds on the order of or below the escape speed of the 60m-sized nucleus. We discuss the implications of our results for the question of whether the dust eruption was triggered by an impact or by rotational break-up.

Agarwal, J.; Jewitt, D.; Weaver, H.; Mutchler, M.; Drahus, M.

2012-09-01

286

Evidence of recent warming and El Nino-related variations in ice breakup of Wisconsin lakes  

USGS Publications Warehouse

Ice breakup dates from 1968 to 1988 were examined for 20 Wisconsin lakes to determine whether consistent interannual and long-term changes exist. Each ice record had a trend toward earlier breakup dates, as demonstrated by a negative slope with time, indicating a recent warming trend. The average change in breakup dates was 0.82 d earlier per year for the lakes in southern Wisconsin, which was more extreme than that for the northern Wisconsin lakes (0.45 d yr-1). Interannual variation in breakup dates was related to the warm phase of El Nino/Southern Oscillation (ENSO) episodes. El Nino events occurred five times during this period (1965, 1972, 1976, 1982, and 1986). Average breakup dates were significantly earlier than average (5-14 d) during the mature phase of El Nino. This variability was affected by the location of the lake: El Nino-related variation was more evident for the southern lakes than the northern lakes. This difference was caused by the average date of breakup for the southern lakes being in late March directly following the period when air temperatures were strongly related to El Nino events, whereas the average dates of breakup of the northern lakes was in mid- to late April following a period when air temperatures were not significantly related to El Nino events. Overall, the interannual and long-term patterns across Wisconsin were relatively consistent, indicating that recent warming and El Nino- related variation are regional climatic responses.

Anderson, W. L.; Robertson, D. M.; Magnuson, J. J.

1996-01-01

287

The northern slope of South China Sea: an ideal site for studying passive margin extension and breakup  

NASA Astrophysics Data System (ADS)

With the advance of hydrocarbon exploration into deep waters of the northern SCS, structural details from continental slope to deepsea basin have been revealed. A striking feature is the dramatic change in Cenozoic extension along and across the strike as well as with the time. Along strike the slope is seperated by lithospheric faults into segments with different amount of Cenozoic extension. The breakup occurred in the no-extension eastern segment (the Chaoshan depression), the most strongly extended central segment (the Baiyun sag) but failed in the western segment of intermediate extension (the Qingdongnan basin). This pattern violates the expectation that breakup occurs at first where the extension reached the maximum. In the central segment, the style of extension varies significantly in dip direction. Differing from the belts of half grabens in the shelf, the extension is expressed as a large downwarp (the Baiyun sag) in the slope, and as irregularly shaped sags (the Liwan sag) near the continental-oceanic boundary (COB). The Baiyun sag (BYS) is the largest and deepest sag in the Pearl River Mouth basin (PRMB). Long-cable MCS revealed that at the center of the BYS the crust thinned to <7 km. Grabens and half-grabens are seen only along the SW border of the BYS in Paleogene and did not control the main subsidence of the sag. In Neogene, swarms of NWW-striking small faults developed in the SW and NE flanks of the sag. These features indicate that ductile extension had dominated the formation of the BYS. Suppose the SCS started opening at 30 Ma (although no breakup unconformity found at 30 Ma in the ODP#1148 well adjacent to the COB), the anomalous post-breakup subsidence in the BYS exceeds that predicted by classical model by 1~2 km and occurred most strongly in several periods. Similar anomalous post-breakup subsidence has been observed also in the shelf. The Liwan sag (LWS) SE of the BYS is an aggregate of NS-, NW-, EW-, and NE-elongated narrow and short sags. Its complex shape differs from that of any other sag in the northern SCS, also differs from that of the lower slope of SE Atlantic margin and the Gulf of Mexico where thrust belts developed by gravitational sliding. Multi-staged magmatic activities have contributed to but could not fully explain the structural complexities of the LWS. Perhaps basement structures have played an important role as the sag might be developed upon the relict Mesozoic West Pacific subduction system. In addition, two horizons of deep-seated waving reflectors are identified beneath the LWS, which are suspected to be respectively a detachment surface and the intra-crustal shear zones related to lower-crust flow. A good understanding of these features may help answering the fundamental question on what controls the style, magnitude, and segmentation of passive margin extension and breakup, what is the mechanism, and what differences between marginal sea and open oceans in their evolution and dynamics. Preliminary attempt has been made taking into account basement structure, kinematics of bounding blocks, lithospheric rheology, lower crustal flow, as well as enhanced sediment supply by monsoon strengthening. This study is funded by CNSF40976033.

Zhou, D.; Sun, Z.; Pang, X.; Wu, X.; Xu, H.; Qiu, N.

2011-12-01

288

From conjugate volcanic rifted margins to micro-continent formation: Double breakup development of the Norwegian-Greenland Sea  

NASA Astrophysics Data System (ADS)

We re-evaluate the structure and spreading evolution of the Norwegian-Greenland Sea and surrounding volcanic (rifted) margins based on new high-resolution aeromagnetic surveys. The new dataset combined with long-offset seismic and gravity data allow us to have a better understanding of the structure and evolution of the conjugate margin systems in the Norwegian-Greenland Sea from the rifting to the drifting stage. We particularly focus on the new JAS-12 aeromagnetic survey acquired between the Aegir Ridge and the Jan Mayen micro-continent, which was initially part of the Møre-Vøring-Greenland rift system. Combined with the previous NB-07 and JAS-05 surveys, our final compilation fully covers the continent-ocean transition and the whole oceanic spreading system from the Møre margin to the conjugate Jan Mayen micro-continent with high quality, high-resolution and reliable magnetic data. The new dataset allowed a new, consistent and precise interpretation of the magnetic polarity chrons and oceanic fractures, providing the basis for more accurate rotation poles estimation, and better basin and crustal reconstructions between Norway, Greenland and the Jan Mayen micro-continent. This dataset allowed us to clarify the pre- and post-breakup configurations of the rift system and discuss the mechanisms involved during the onset of the two phases of breakup leading to the micro-continent formation. Our observations and models suggest that the pre-breakup rift system evolved through a significant Late Jurassic-Cretaceous thinning phase. This episode led to a significant thinning of the continental crust and an exhumation of pre-existing lower crust. However, we have not been able to identify and/or validate any clear domains of exhumed and denudated serpentinised mantle. The first Eocene breakup is mostly characterised by severe magmatism (sill, SDRS). Lithospheric/asthenospheric processes leading to rift localisation do not necessarily represent a continuum of lithospheric deformation with the precedent thinning system. Diking and disconnected lithospheric plumbing are proposed to explain the Eocene breakup. After the first phase of continental breakup, two major phases of spreading influenced the Norwegian-Greenland Sea. Phase I (from C24 to C21r, ~54 to 49 Ma) marks the earliest phase of spreading, probably initiated in the central and outer part of the Møre Basin. During this period, the formation of overlapping systems and pseudo-fault development, indirectly influenced by the proto-margin segmentation, suggests the presence of additional micro-plates in the Norwegian-Greenland Sea. We also observed a significant change in the oceanic spreading system in the late Early Eocene. Based on observations from the surrounding areas, this supports a major and distinct tectonic and magmatic event in the Norwegian-Greenland Sea at around C21r (49-47.9 Ma), the beginning of a second phase. During Phase II, from C21r-C12 or possibly younger (48-<32 Ma) of the Norway Basin development, spreading rates decreased, spreading direction changed leading to the formation of unexpected N-S oriented oceanic fracture zones. Phase II probably coincides with the climax of extension and possibly local spreading that is suspected in the southern part of the Jan Mayen micro-continent forming a complex area of oceanic, transitional and continental fragments before its complete dislocation from East Greenland in Latest Oligocene.

Gernigon, Laurent; Blischke, Anett; Nasuti, Aziz; Olesen, Odleiv; Sand, Morten; Sveinn Arnarson, Thorarinn

2014-05-01

289

Resonant breakup in the 6,7Li + 144Sm systems  

NASA Astrophysics Data System (ADS)

Resonant breakup processes in the 6,7Li + 144Sm systems is studied through the results obtained in exclusive measurements performed at energies around the Coulomb barrier and a kinematical description of these phenomena is introduced. For the 7Li projectile, dominance of transfer breakup through the 6Li first excited state is observed. In the 6Li projectile case, elastic breakup through the same projectile-like excited state clearly dominates the experimental yield. Relative and absolute cross sections for both systems are calculated. A clear asymmetry is observed in the intrinsic angular distributions, in good agreement with results reported for other known systems.

Heimann, D. Martinez; Pacheco, A. J.; Capurro, O. A.; Arazi, A.; Carnelli, P. F. F.; Cardona, M. A.; de Barbará, E.; Fernández Niello, J. O.; Figueira, J. M.; Fimiani, L.; Hojman, D. L.; Martí, G. V.; Negri, A.

2012-02-01

290

Breakup excitation function at backward angles from ?-spectra in the 6Li + 144Sm system  

NASA Astrophysics Data System (ADS)

Breakup cross sections were obtained for the 6Li + 144Sm system at energies above and below the Coulomb barrier from a detailed analysis of the data recorded at backward angles. These cross sections are compared with inelastic target excitations previously reported revealing a similar behavior as a function of the bombarding energy but a large absolute difference between them. Using kinematical considerations we have analyzed possible contributions from different breakup channels and we have extracted information on magnitudes such as the relative kinetic energies of the corresponding breakup fragments.

Capurro, O. A.; Pacheco, A. J.; Arazi, A.; Figueira, J. M.; Martinez Heimann, D.; Negri, A. E.

2011-01-01

291

Magma-assisted strain migration during the progression from rifting to break-up  

NASA Astrophysics Data System (ADS)

It is important to understand a mechanism of the strain redistribution in order to progress our understanding of sedimentary basin migration and/or continental-ribbon/micro-continent insulation. The change in the lithospheric strength due to thermal relaxation and/or replacement of weaker crust with stronger mantle has usually been considered as a possible mechanism that cases successive deformation to migrate to adjacent regions. This is, however, hardly applicable for an extensional process that can lead to continental break-up. In our previous studies (Yamasaki and Gernigon, Tectonophysics, 468, 169-184, 2009; J. Geol. Soc. Lond., 167, 961-971, 2010), the effect of underplated mafic bodies (UPMB) on the redistribution of extensional strain was examined quantitatively, in which UPMB is emplaced beneath a different region some time after the first rifting process has initiated. It was showed that there possibly exist three different modes of strain redistribution, 1) a shift-completed mode: the strain is completely shifted into a newly weakened region, 2) a transition mode: the strain is redistributed, but lithospheric extension is accommodated by thinning in two regions and 3) a shift-failed mode where the strain is not redistributed. The modes are dependent on the configuration of UPMB and on the initial rheological heterogeneity in the initially deformed region, but it becomes difficult for any UPMB to initiate the redistribution of the deformation once the stretching factor in the first deformed region exceeds a critical value. The general model behaviour can characterise the dynamic process of the strain migration, in terms of which the geological process observed during rifting and break-up is discussed in this study, providing an important implication for a typical rift/margin configuration that the shift-completed or transition mode can be applied for the regions where UPMB has been clearly observed (e.g., the Indian Ocean, the Norwegian-Greenland Sea, the Red Sea/Afar region, the Western Barents Sea and the Brazilian margin).

Yamasaki, Tadashi; Gernigon, Laurent

2013-04-01

292

Simulations of insonated contrast agents: Saturation and transient break-up  

NASA Astrophysics Data System (ADS)

Under insonation contrast agents are known to perform nonlinear pulsations and deform statically, in the form of buckling, or dynamically via parametric mode excitation, and often exhibit jetting and break-up like bubbles without coating. Boundary element simulations are performed in the context of axisymmetry in order to establish the nonlinear evolution of these patterns. The viscoelastic stresses that develop on the coating form the dominant force balance tangentially to the shell-liquid interface, whereas the dynamic overpressure across the shell balances viscoelastic stresses in the normal direction. Strain softening and strain hardening behavior is studied in the presence of shape instabilities for various initial conditions. Simulations recover the pattern of static buckling, subharmonic/harmonic excitation, and dynamic buckling predicted by linear stability. Preferential mode excitation during compression is obtained supercritically for strain softening phospholipid shells while the shell regains its sphericity at expansion. It is a result of energy transfer between the emerging unstable modes and the radial mode, eventually leading to saturated oscillations of shape modes accompanied by asymmetric radial pulsations in favor of compression. Strain softening shells are more prone to sustain saturated pulsations due to the mechanical behavior of the shell. As the sound amplitude increases and before the onset of dynamic buckling, both types of shells exhibit transient break-up via unbalanced growth of a number of unstable shape modes. The effect of pre-stress in lowering the amplitude threshold for shape mode excitation is captured numerically and compared against the predictions of linear stability analysis. The amplitude interval for which sustained shape oscillations are obtained is extended, in the presence of pre-stress, by switching from a strain softening constitutive law to a strain hardening one once the shell curvature increases beyond a certain level. This type of mechanical behavior models the formation of lipid bilayer structures on the shell beyond a certain level of bending, as a result of a lipid monolayer folding transition. In this context a compression only type behavior is obtained in the simulations, which is accompanied by preferential shape deformation during compression at relatively small sound amplitudes in a manner that bears significance on the interpretation of available experimental observations exhibiting similar dynamic behavior.

Tsigklifis, Kostas; Pelekasis, Nikos A.

2013-03-01

293

Deuteron-induced reactions on Y89 and nuclear level density of 90Zr  

NASA Astrophysics Data System (ADS)

Experimental elastic scattering and double differential cross sections of 89Y(d ,n) and 89Y(d ,p) reactions have been measured with 5, 6, and 7.44 MeV deuteron beams. It was found that about 76% of the total reaction cross sections are determined by the compound mechanism and the rest is due to direct and preequilibrium interactions. Cross sections measured at backward angles were compared with calculations based on the compound nuclear Hauser-Feshbach model. It was found that it is possible to reproduce the backward angle neutron cross sections by the compound model, but it fails to describe proton cross sections. A pronounced peak is observed in neutron differential cross section which might result from strongly populated states 0+,4-, and 5- of 90Zr via direct stripping reactions. The level density of 90Zr has been obtained from neutron cross sections measured at backward angles. It is best described with the constant-temperature level density model versus the traditional Fermi-gas one.

Byun, Y.; Ramirez, A. P. D.; Grimes, S. M.; Voinov, A. V.; Brune, C. R.; Massey, T. N.

2014-10-01

294

Energy and Mass Dependence of Deuterons by Macroscopically Optical Model in Range of Coulomb Barrier till 200 Mev  

NASA Astrophysics Data System (ADS)

The joint analyze of experimental data of interactions deuterons on nuclei 6Li, 16O, 32S, 50V, 51V, 70Ge, 72Ge, 90Zr, 116Sn in range of Coulomb barrier till 200 MeV is presented. The global parameters as mass and energy dependence of deuterons with energies till 200 MeV by macroscopically optical model of deuterons were analyzed.

Kuterbekov, K. A.; Kabyshev, A. M.; Kabdrakhimov, G. D.; Almanov, G. A.; Soltabayev, B.; Urazina, I.; Penionzhkevich, Yu. E.; Sobolev, Yu. G.; Kuchtina, I. N.; Sadykov, B. M.; Mukhametzhan, A. M.; Khussainov, Ye. K.; Nurmukhanbetova, A. K.

2013-06-01

295

Numerical simulation of the deformation and breakup of droplets subjected to complex, time dependent strain rates  

E-print Network

Numerical simulation of the deformation and breakup of droplets subjected to complex, time been carried out. A volumeoffluid (VOF) method, previously used to simulate numerically firstly to generate strain rate histories that droplets experience and secondly to simulate the effect

Renardy, Yuriko

296

11Li Breakup on 208 at energies around the Coulomb barrier.  

PubMed

The inclusive breakup for the (11)Li + (208)Pb reaction at energies around the Coulomb barrier has been measured for the first time. A sizable yield of (9)Li following the (11)Li dissociation has been observed, even at energies well below the Coulomb barrier. Using the first-order semiclassical perturbation theory of Coulomb excitation it is shown that the breakup probability data measured at small angles can be used to extract effective breakup energy as well as the slope of B(E1) distribution close to the threshold. Four-body continuum-discretized coupled-channels calculations, including both nuclear and Coulomb couplings between the target and projectile to all orders, reproduce the measured inclusive breakup cross sections and support the presence of a dipole resonance in the (11)Li continuum at low excitation energy. PMID:25166983

Fernández-García, J P; Cubero, M; Rodríguez-Gallardo, M; Acosta, L; Alcorta, M; Alvarez, M A G; Borge, M J G; Buchmann, L; Diget, C A; Falou, H A; Fulton, B R; Fynbo, H O U; Galaviz, D; Gómez-Camacho, J; Kanungo, R; Lay, J A; Madurga, M; Martel, I; Moro, A M; Mukha, I; Nilsson, T; Sánchez-Benítez, A M; Shotter, A; Tengblad, O; Walden, P

2013-04-01

297

Thermonuclear breakup reactions of light nuclei. II - Gamma-ray line production and other applications  

NASA Technical Reports Server (NTRS)

The main consequence of nuclear breakup reactions in high-temperature plasmas is shown to be to reduce the production of the gamma-ray lines, due to the breakup of these species at high temperature. Results of the emissivities of all the relevant gamma-ray lines are discussed. It is shown that the magnitude of the breakup effect on the line emissivities depends strongly on temperature, but more importantly on the plasma density and on the available time for the ion processes. Other effects considered include the production of neutrons (from the breakup of helium) and its consequences (such as the production of gamma rays from n-capture reactions and dynamical effects in accretion disk plasmas).

Guessoum, Nidhal

1989-01-01

298

The recent breakup of an asteroid in the main-belt region  

E-print Network

............................................................................................................................................................................. The present population of asteroids in the main belt is largely the result of many past collisions1 tens of major collisions (that is, asteroid families) have been observed in the main belt9.............................................................. The recent breakup of an asteroid

Nesvorny, David

299

Effects of polymer concentration and molecular weight on the dynamics of visco-elasto-capillary breakup  

E-print Network

Capillary-break-up measurements of viscoelastic polymer solutions are performed using a Capillary Breakup Extensional Rheometer (CABER). The device consists of two coaxial plates which are used to form and hold a liquid ...

Verani, Matthieu, 1977-

2004-01-01

300

Measurement of inclusive spin structure functions of the deuteron  

NASA Astrophysics Data System (ADS)

We report the results of a new measurement of spin structure functions of the deuteron in the region of moderate momentum transfer [Q2=0.27 1.3 (GeV/c)2] and final hadronic state mass in the nucleon resonance region (W=1.08 2.0 GeV). We scattered a 2.5 GeV polarized continuous electron beam at Jefferson Lab off a dynamically polarized cryogenic solid state target (15ND3) and detected the scattered electrons with the CEBAF large acceptance spectrometer. From our data, we extract the longitudinal double spin asymmetry A|| and the spin structure function gd1. Our data are generally in reasonable agreement with existing data from SLAC where they overlap, and they represent a substantial improvement in statistical precision. We compare our results with expectations for resonance asymmetries and extrapolated deep inelastic scaling results. Finally, we evaluate the first moment of the structure function gd1 and study its approach to both the deep inelastic limit at large Q2 and to the Gerasimov-Drell-Hearn sum rule at the real photon limit (Q2?0). We find that the first moment varies rapidly in the Q2 range of our experiment and crosses zero at Q2 between 0.5 and 0.8 (GeV/c)2, indicating the importance of the ? resonance at these momentum transfers.

Yun, J.; Kuhn, S. E.; Dodge, G. E.; Forest, T. A.; Taiuti, M.; Adams, G. S.; Amaryan, M. J.; Anciant, E.; Anghinolfi, M.; Asavapibhop, B.; Asryan, G.; Audit, G.; Auger, T.; Avakian, H.; Barrow, S.; Battaglieri, M.; Beard, K.; Bektasoglu, M.; Bertozzi, W.; Bianchi, N.; Biselli, A. S.; Boiarinov, S.; Bosted, P.; Bouchigny, S.; Bradford, R.; Branford, D.; Brooks, W. K.; Bueltmann, S.; Burkert, V. D.; Butuceanu, C.; Calarco, J. R.; Carman, D. S.; Carnahan, B.; Cetina, C.; Ciciani, L.; Cole, P. L.; Coleman, A.; Connelly, J.; Cords, D.; Corvisiero, P.; Crabb, D.; Crannell, H.; Cummings, J.; Sanctis, E. De; Vita, R. De; Degtyarenko, P. V.; Demirchyan, R. A.; Denizli, H.; Dennis, L. C.; Dharmawardane, K. V.; Djalali, C.; Domingo, J.; Doughty, D.; Dragovitsch, P.; Dugger, M.; Dytman, S.; Eckhause, M.; Efremenko, Y. V.; Egiyan, H.; Egiyan, K. S.; Elouadrhiri, L.; Empl, A.; Farhi, L.; Fatemi, R.; Feuerbach, R. J.; Ficenec, J.; Fissum, K.; Freyberger, A.; Frolov, V.; Funsten, H.; Gaff, S. J.; Gai, M.; Gavalian, G.; Gavrilov, V. B.; Gilad, S.; Gilfoyle, G. P.; Giovanetti, K. L.; Girard, P.; Golovatch, E.; Gordon, C. I.; Griffioen, K. A.; Guidal, M.; Guillo, M.; Guo, L.; Gyurjyan, V.; Hadjidakis, C.; Hancock, D.; Hardie, J.; Heddle, D.; Heimberg, P.; Hersman, F. W.; Hicks, K.; Hicks, R. S.; Holtrop, M.; Hu, J.; Hyde-Wright, C. E.; Ito, M. M.; Jenkins, D.; Joo, K.; Keith, C.; Kelley, J. H.; Khandaker, M.; Kim, K. Y.; Kim, K.; Kim, W.; Klein, A.; Klein, F. J.; Klimenko, A. V.; Klusman, M.; Kossov, M.; Kramer, L. H.; Kuang, Y.; Kuhn, J.; Lachniet, J.; Laget, J. M.; Lawrence, D.; Leksin, G. A.; Loukachine, K.; Major, R. W.; Manak, J. J.; Marchand, C.; McAleer, S.; McNabb, J. W.; McCarthy, J.; Mecking, B. A.; Mestayer, M. D.; Meyer, C. A.; Minehart, R.; Mirazita, M.; Miskimen, R.; Mokeev, V.; Morrow, S.; Muccifora, V.; Mueller, J.; Murphy, L. Y.; Mutchler, G. S.; Napolitano, J.; Nelson, S. O.; Niccolai, S.; Niculescu, G.; Niczyporuk, B.; Niyazov, R. A.; Nozar, M.; O'Rielly, G. V.; Ohandjanyan, M. S.; Opper, A.; Ossipenko, M.; Park, K.; Patois, Y.; Peterson, G. A.; Philips, S.; Pivnyuk, N.; Pocanic, D.; Pogorelko, O.; Polli, E.; Preedom, B. M.; Price, J. W.; Protopopescu, D.; Qin, L. M.; Raue, B. A.; Riccardi, G.; Ricco, G.; Ripani, M.; Ritchie, B. G.; Rock, S.; Ronchetti, F.; Rossi, P.; Rowntree, D.; Rubin, P. D.; Sabourov, K.; Salgado, C. W.; Sapunenko, V.; Sargsyan, M.; Schumacher, R. A.; Serov, V. S.; Sharabian, Y. G.; Shaw, J.; Shuvalov, S. M.; Simionatto, S.; Skabelin, A.; Smith, E. S.; Smith, L. C.; Smith, T.; Sober, D. I.; Sorrell, L.; Spraker, M.; Stepanyan, S.; Stoler, P.; Taylor, S.; Tedeschi, D.; Thoma, U.; Thompson, R.; Todor, L.; Tung, T. Y.; Tur, C.; Vineyard, M. F.; Vlassov, A.; Wang, K.; Weinstein, L. B.; Weller, H.; Welsh, R.; Weygand, D. P.; Whisnant, S.; Witkowski, M.; Wolin, E.; Wood, M. H.; Yegneswaran, A.; Zhang, B.; Zhao, J.; Zhou, Z.

2003-05-01

301

Quasi-free photoproduction of ?-mesons off the deuteron  

NASA Astrophysics Data System (ADS)

Precise data for quasi-free photoproduction of ?-mesons off the deuteron have been measured at the Bonn ELSA accelerator with the combined Crystal Barrel/TAPS detector for incident photon energies up to 2.5GeV. The ?-mesons have been detected in coincidence with recoil protons and neutrons. Possible nuclear effects like Fermi motion and re-scattering can be studied via a comparison of the quasi-free reaction off the bound proton to ?-production off the free proton. No significant effects beyond the folding of the free cross-section with the momentum distribution of the bound protons have been found. These Fermi motion effects can be removed by an analysis using the invariant mass of the ?-nucleon pairs reconstructed from the final-state four-momenta of the particles. The total cross-section for quasi-free ?-photoproduction off the neutron reveals even without correction for Fermi motion a pronounced bump-like structure around 1GeV of incident photon energy, which is not observed for the proton. This structure is even narrower in the invariant-mass spectrum of the ?-neutron pairs. Position and width of the peak in the invariant-mass spectrum are W ? 1665 MeV and FWHM ? ? 25 MeV. The data are compared to the results of different models.

Jaegle, I.; Krusche, B.; Anisovich, A. V.; Bacelar, J. C. S.; Bantes, B.; Bartholomy, O.; Bayadilov, D. E.; Beck, R.; Beloglazov, Y. A.; Castelijns, R.; Crede, V.; Dieterle, M.; Dutz, H.; Elsner, D.; Ewald, R.; Frommberger, F.; Funke, C.; Gothe, R.; Gregor, R.; Gridnev, A. B.; Gutz, E.; Hillert, W.; Höffgen, S.; Hoffmeister, P.; Horn, I.; Junkersfeld, J.; Kalinowsky, H.; Kammer, S.; Keshelashvili, I.; Kleber, V.; Klein, Frank; Klein, Friedrich; Klempt, E.; Konrad, M.; Kotulla, M.; Lang, M.; Löhner, H.; Lopatin, I. V.; Lugert, S.; Maghrbi, Y.; Menze, D.; Mertens, T.; Messchendorp, J. G.; Metag, V.; Nikonov, V. A.; Nanova, M.; Novinski, D. V.; Novotny, R.; Oberle, M.; Ostrick, M.; Pant, L. M.; van Pee, H.; Pfeiffer, M.; Pheron, F.; Roy, A.; Sarantsev, A. V.; Schadmand, S.; Schmidt, C.; Schmieden, H.; Schoch, B.; Shende, S. V.; Sokhoyan, V.; Süle, A.; Sumachev, V. V.; Szczepanek, T.; Thoma, U.; Trnka, D.; Varma, R.; Walther, D.; Wendel, C.; Werthmüller, D.; Witthauer, L.

2011-08-01

302

Neutron Polarisabilities from Deuteron Compton Scattering in \\chiEFT  

E-print Network

Chiral Effective Field Theory is for photon energies up to 200 MeV the tool to accurately determine the polarisabilities of the neutron from deuteron Compton scattering. A multipole analysis reveals that dispersive effects from an explicit Delta(1232) prove in particular indispensable to understand the data at 95 MeV measured at SAL. Simple power-counting arguments derived from nuclear phenomenology lead to the correct Thomson limit and gauge invariance. At next-to-leading order, the static scalar dipole polarisabilities are extracted as identical for proton and neutron within the error-bar of available data: \\alpha^n=11.6\\pm1.5_stat\\pm0.6_Baldin, \\beta^n=3.6\\mp1.5_stat\\pm0.6_Baldin for the neutron, in units of 10^-4 fm^3, compared to \\alpha^p=11.0\\pm1.4_stat\\pm0.4_Baldin, \\beta}^p=2.8\\mp1.4_stat\\pm0.4_Baldin for the proton in the same framework. New experiments e.g. at MAXlab (Lund) will improve the statistical error-bar.

Griesshammer, Harald W

2007-01-01

303

Neutron Polarisabilities from Deuteron Compton Scattering in \\chiEFT  

E-print Network

Chiral Effective Field Theory is for photon energies up to 200 MeV the tool to accurately determine the polarisabilities of the neutron from deuteron Compton scattering. A multipole analysis reveals that dispersive effects from an explicit Delta(1232) prove in particular indispensable to understand the data at 95 MeV measured at SAL. Simple power-counting arguments derived from nuclear phenomenology lead to the correct Thomson limit and gauge invariance. At next-to-leading order, the static scalar dipole polarisabilities are extracted as identical for proton and neutron within the error-bar of available data: \\alpha^n=11.6\\pm1.5_stat\\pm0.6_Baldin, \\beta^n=3.6\\mp1.5_stat\\pm0.6_Baldin for the neutron, in units of 10^-4 fm^3, compared to \\alpha^p=11.0\\pm1.4_stat\\pm0.4_Baldin, \\beta}^p=2.8\\mp1.4_stat\\pm0.4_Baldin for the proton in the same framework. New experiments e.g. at MAXlab (Lund) will improve the statistical error-bar.

Harald W. Griesshammer

2007-10-15

304

Neutron Polarizabilities From Compton Scattering on the Deuteron?  

E-print Network

A calculation of deuteron Compton scattering using non-relativistic perturbation theory is presented,with the primary motivation of investigating the feasibility of determining the neutron polarizabilities from this type of experiment. This calculation is expected to be valid for energies below 100 MeV. Pion-exchange, relativistic, and recoil corrections are also included. The low-energy theorem for gauge invariance is shown to be satisfied. The relative effects of the different terms and their effects on the determinations of the polarizabilities are discussed at energies of 49, 69, and 95 MeV. The cross-section is dominated by the seagull, polarizability, and electromagnetic multipole interactions. Relativistic and pion-exchange terms are also important, while recoil corrections and multipoles of $L$=2 and greater are negligible. The calculation provides a reasonable description of the experimental data points at 49 and 69 MeV. The polarizabilities are difficult to determine at these energies. A more accurate determination of the polarizabilities may be possible at 95 MeV.

Jonathan J. Karakowski; Gerald A. Miller

1999-01-08

305

Asymptotic normalization coefficients and spectroscopic factors from deuteron stripping reactions  

NASA Astrophysics Data System (ADS)

We present the analysis of three deuteron stripping reactions, C14(d,p)C15,Ni58(d,p)Ni59, and Sn116(d,p)Sn117 using the combined method [A. M. Mukhamedzhanov and F. M. Nunes, Phys. Rev. C 72, 017602 (2005), 10.1103/PhysRevC.72.017602], in which each reaction is analyzed at low and significantly higher energies. At low energies all these reactions are peripheral and the experimental asymptotic normalization coefficients (ANCs) are determined with accuracy about 10%. At higher energies we determine the spectroscopic factors (SFs) by fixing the normalization of the peripheral parts of the reaction amplitudes governed by the ANCs found from the low-energy data. The combined method imposes a strict limitation on the variation of the geometrical parameters of the single-particle potential, which can be arbitrarily taken in the standard approach. By checking the compatibility of the ANCs and SFs using the combined method we reveal the flaw in the contemporary nuclear reaction theory in treating the nuclear interior, which is the most crucial part in the determination of the SFs.

Pang, D. Y.; Mukhamedzhanov, A. M.

2014-10-01

306

Capillary and acceleration wave breakup of liquid jets in axial-flow airstreams  

NASA Technical Reports Server (NTRS)

Empirical correlations of reciprocal mean drop diameter with airstream momentum were derived from capillary and acceleration wave breakup of liquid jets atomized by cross stream injection into axial flow airstreams. A scanning radiometer was used to obtain data over an airstream momentum range of 3.7 to 25.7 g/sq cm sec. Transition from capillary to acceleration wave breakup was obtained at a critical Weber-Reynolds number of 1,000,000.

Ingebo, R. D.

1981-01-01

307

Initial breakup of a small-diameter liquid jet by a high-speed gas stream  

Microsoft Academic Search

The situation of a small-diameter liquid jet exposed to a large-diameter high-speed gas jet (gas-to-liquid nozzle area ratio of order 100 to 1000) is investigated experimentally. Flow visualization and particle-sizing techniques are employed to examine the initial jet breakup process and primary liquid atomization. Observations of the initial breakup of the liquid jet in the near-nozzle region, combined with droplet-size

C. M. Varga; J. C. Lasheras; E. J. Hopfinger

2003-01-01

308

Hard Break-Up of Two-Nucleons and QCD Dynamics of NN Interaction  

NASA Astrophysics Data System (ADS)

We investigate hard photodisintegration of two nucleons from ^3He nucleus within the framework of hard rescattering model (HRM). In HRM a quark of one nucleon knocked-out by incoming photon rescatters with a quark of the other nucleon leading to the production of two nucleons with high relative momentum. HRM allows to express the amplitude of two-nucleon break-up reaction through the convolution of photon-quark scattering, NN hard scattering amplitude and nuclear spectral function which can be calculated using nonrelativistic ^3He wave function. HRM predicts several specific features for hard break-up reaction. First, the cross section will approximately scale as s-11. Also one predicts comparable or larger cross section for pp break up as compared to that of pn break-up, which is opposite to what is observed in low energy kinematics. Another result is the prediction of different spectator momentum dependencies of pp and pn break-up cross sections. This is due to the fact that same-helicity pp-component is strongly suppressed in the ground state wave function of ^3He. Due to this suppression HRM predicts significantly different asymmetries for the cross section of polarization transfer NN break-up reactions for circularly polarized photons. For the pp break-up this asymmetry is predicted to be zero while for the pn it is close to 23.

Sargsian, Misak; Granados, Carlos

2009-05-01

309

Simulation of slide-coating flows using a fixed grid and a volume-of- fluid front-tracking technique: Startup and bead breakup  

SciTech Connect

Slide coating flow is a workhorse process for manufacturing precision film-coating products. Properly starting up a slide coating process is very important in reducing wastage during startup and ensuring that the process operates within the desired `coating window.` A two-phase flow analysis of slide-coating startup was performed by Palmquist and Scriven (1994) using Galerkin`s method with finite-element basis functions and an elliptic mesh generation scheme. As reported by Chen (1992) from flow visualization experiments, a continuously coated liquid film breaks up into rivulets, which are coating stripes with dry lanes in between, when the coated film becomes thinner and thinner due to either the increase in substrate speed or the reduction in pre-metered feed-liquid pump speed. It was observed that the coated-film breakup process originated from the coating bead, thus the name of bead breakup. Understanding the bead-breakup phenomena and elucidating mechanisms involved will provide guidance for manufacturing thinner coating, an industrial trend for better product performance. In this paper we present simulation results of slide-coating flows obtained from a computational method capable of describing arbitrary, three-dimensional and time-dependent deformations. The method, which is available in a commercial code, uses a fixed grid through which fluid interfaces are tracked by a Volume-of-Fluid technique (Hirt and Nichols, 1981). Surface tension, wall adhesion, and viscous stresses are fully accounted for in our analysis. We illustrate our computational approach by application to startup and the bead-breakup problems. As will be shown, for rapid processes our approach offers the computational efficiency and robustness that are difficult o achieve in conventional finite-element-based methods.

Hirt, C.W. [Flow Science, Inc., Los Alamos, NM (United States); Chen, K.S. [Sandia National Labs., Albuquerque, NM (United States)

1996-03-01

310

Beam break-up estimates for the ERL at BNL  

SciTech Connect

A prototype Ampere-class superconducting energy recovery linac (ERL) is under advanced construction at BNL. The ERL facility is comprised of a five-cell SC Linac plus a half-cell SC photo-injector RF electron gun, both operating at 703.75 MHz. The facility is designed for either a high-current mode of operation up to 0.5 A at 703.75 MHz or a high-bunch-charge mode of 5 nC at 10 MHz bunch frequency. The R&D facility serves a test bed for an envisioned electron-hadron collider, eRHIC. The high-current, high-charge operating parameters make effective higher-order-mode (HOM) damping mandatory, and requires the determination of HOM tolerances for a cavity upgrade. The niobium cavity has been tested at superconducting temperatures and has provided measured quality factors (Q) for a large number of modes. These numbers were used for the estimate of the beam breakup instability (BBU). The facility will be assembled with a highly flexible lattice covering a vast operational parameter space for verification of the estimates and to serve as a test bed for the concepts directed at future projects.

Ben-Zvi, I.; Calaga, R.; Hahn, H.; Hammons, L.; Johnson, E.; Kayran, D.; Litvinenko, V.; Kewisch, J.; Xu, W.

2010-05-23

311

Asteroid breakup linked to the Great Ordovician Biodiversification Event  

NASA Astrophysics Data System (ADS)

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.

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

312

Breakup of {sup 12}C resonances into three alpha particles  

SciTech Connect

The reaction {sup 3}He+{sup 11}B->d+{sup 12}C* has been used to populate resonances in {sup 12}C up to an excitation energy of 15 MeV. The subsequent breakup to three alpha particles has been measured in complete kinematics. Dalitz plots are used to visualize and analyze the data. The Dalitz plot intensity distribution exhibits zero points characteristic of the total spin and parity of the 3alpha system allowing us to determine the spin and parity of a state in {sup 12}C at 13.35 MeV whose quantum numbers were hitherto not well established. The Dalitz plot intensity distributions of the 2{sup -} state at 11.83 MeV and the 1{sup +} state at 12.71 MeV are compared with the predictions of a recent three-body calculation as well as with simpler models. All are able to reproduce the gross structures seen in the Dalitz plot, but none give an accurate description of the detailed profile of the distributions.

Kirsebom, O. S.; Fynbo, H. O. U.; Hyldegaard, S.; Riisager, K. [Department of Physics and Astronomy, Aarhus University, DK-8000 Aarhus C (Denmark); Alcorta, M.; Borge, M. J. G.; Cubero, M.; Dominguez-Reyes, R.; Madurga, M.; Perea, A.; Tengblad, O. [Instituto de Estructura de la Materia, CSIC, ES-28006 Madrid (Spain); Diget, C. A.; Fulton, B. R. [Department of Physics, University of York, York YO10 5DD (United Kingdom); Fraile, L. M. [PH Department, CERN, CH-1211 Geneva 23 (Switzerland); Jonson, B.; Nilsson, T.; Nyman, G. [Fundamental Physics, Chalmers University of Technology, SE-41296 Goeteborg (Sweden); Munoz Martin, A. [CMAM, Universidad Autonoma de Madrid, Cantoblanco, ES-28049 Madrid (Spain)

2010-06-15

313

Inferences concerning the magnetospheric source region for auroral breakup  

NASA Technical Reports Server (NTRS)

Inferences concerning the magnetospheric source region for auroral arcs obtained from particle measurements on polar orbiting satellites are presented and contrasted with other ideas. An argument that the magnetospheric source region for auroral arc breakup and substorm initiation is along Boundary Plasma Sheet (BPS) magnetic field lines is given. This source region lies beyond a distinct central plasma sheet region and sufficiently far from the Earth that energetic ion motion violates the guiding center approximation (is chaotic). The source region is not constrained to any particular range of distances from the Earth, and substorm initiation may be possible over a wide range of distances from near synchronous orbit to the distant tail. It is also argued that the layer of low energy electrons and velocity dispersed ion beams observed at low altitudes on Aureol 3 is not a different region from the region of auroral arcs. Both comprise the BPS. The two regions occasionally appear distinct at low altitudes because of the effects of arc field aligned potential drops on precipitating particles.

Lyons, L. R.

1992-01-01

314

Panjal Paleomagnetism: Implications for Early Permian Gondwana break-up  

NASA Astrophysics Data System (ADS)

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.

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

2013-12-01

315

Breakup of evaporating/burning slurry drops by additives  

NASA Astrophysics Data System (ADS)

Single drops of silicon carbide-cumene slurry were suspended from a quartz fiber and ignited. An inert material such as silicon carbide was chosen so that the droplets can be burned until all the fuel is consumed and only the inert residue is left on the quartz fiber. Benzoyl peroxide was added to cumene and the time to disruption of the liquid drop was measured. In the case of benzoyl peroxide, the breaking up of the drop resulting from its thermal decomposition produced CO 2. Both the drop disruption time and the burning of the slurry to dryness were predicted theoretically. Radiation absorption was found to be an important factor in the case of the slurry. Benzoyl peroxide and carbamide peroxide were investigated as additives to a boron slurry to determine if effective drop break-up could be achieved. Both additives produced drop shattering. The carbamide peroxide was particularly effective due to the production of O 2. The green flame associated with boron burning was clearly evident.

Choudhury, P. Roy; Gerstein, M.

316

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

SciTech Connect

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.

Lechman, Jeremy B.

2010-10-01

317

Electric field induced sheeting and breakup of dielectric liquid jets  

NASA Astrophysics Data System (ADS)

We report experimental observations of the controlled deformation of a dielectric liquid jet subjected to a local high-voltage electrostatic field in the direction normal to the jet. The jet deforms to the shape of an elliptic cylinder upon application of a normal electrostatic field. As the applied electric field strength is increased, the elliptic cylindrical jet deforms permanently into a flat sheet, and eventually breaks-up into droplets. We interpret this observation—the stretch of the jet is in the normal direction to the applied electric field—qualitatively using the Taylor-Melcher leaky dielectric theory, and develop a simple scaling model that predicts the critical electric field strength for the jet-to-sheet transition. Our model shows a good agreement with experimental results, and has a form that is consistent with the classical drop deformation criterion in the Taylor-Melcher theory. Finally, we statistically analyze the resultant droplets from sheet breakup, and find that increasing the applied electric field strength improves droplet uniformity and reduces droplet size.

Khoshnevis, Ahmad; Tsai, Scott S. H.; Esmaeilzadeh, Esmaeil

2014-01-01

318

Strain distribution across magmatic margins during the breakup stage: Seismicity patterns in the Afar rift zone  

NASA Astrophysics Data System (ADS)

Fault patterns record the strain history along passive continental margins, but geochronological constraints are, in general, too sparse to evaluate these patterns in 3D. The Afar depression in Ethiopia provides a unique setting to evaluate the time and space relations between faulting and magmatism across an incipient passive margin that formed above a mantle plume. The margin comprises a high elevation flood basalt province with thick, underplated continental crust, a narrow fault-line escarpment underlain by stretched and intruded crust, and a broad zone of highly intruded, mafic crust lying near sealevel. We analyze fault and seismicity patterns across and along the length of the Afar rift zone to determine the spatial distribution of strain during the final stages of continental breakup, and its relation to active magmatism and dike intrusions. Seismicity data include historic data and 2005-2007 data from the collaborative US-UK-Ethiopia Afar Geodynamics Project that includes the 2005-present Dabbahu rift episode. Earthquake epicenters cluster within discrete, 50 km-long magmatic segments that lack any fault linkage. Swarms also cluster along the fault-line scarp between the unstretched and highly stretched Afar rift zone; these earthquakes may signal release of stresses generated by large lateral density contrasts. We compare Coulomb static stress models with focal mechanisms and fault kinematics to discriminate between segmented magma intrusion and crank- arm models for the central Afar rift zone.

Brown, C.; Ebinger, C. J.; Belachew, M.; Gregg, T.; Keir, D.; Ayele, A.; Aronovitz, A.; Campbell, E.

2008-12-01

319

Oceanic-type accretion may begin before complete continental break-up  

NASA Astrophysics Data System (ADS)

Oceanic accretion is thought to be the process of oceanic crust (and lithosphere) edification through adiabatic melting of shallow convecting mantle at oceanic spreading ridges. It is usually considered as a post-breakup diagnostic process following continents rupturing. However, this is not always correct. The structure of volcanic passive margins (representing more than 50% of passive continental margins) outlines that the continental lithosphere is progressively changed into oceanic-type lithosphere during the stage of continental extension. This is clear at least, at crustal level. The continental crust is 'changed' from the earliest stages of extension into a typical -however thicker- oceanic crust with the typical oceanic magmatic layers (from top to bottom: lava flows/tuffs, sheeted dyke complexes, dominantly (sill-like) mafic intrusions in the lower crust). The Q-rich continental crust is highly extended and increases in volume (due to the magma) during the extensional process. At the continent-ocean transition there is, finally, no seismic difference between this highly transformed continental crust and the oceanic crust. Using a large range of data (including deep seismic reflection profiles), we discuss the mantle mechanisms that governs the process of mantle-assisted continental extension. We outline the large similarity between those mantle processes and those acting at purely-oceanic spreading axis and discuss the effects of the inherited continental lithosphere in the pattern of new mafic crust edification.

Geoffroy, L.; Zalan, P. V.; Viana, A. R.

2011-12-01

320

Effects of Breakup of Weakly Bound Projectile and Neutron Transfer on Fusion Reactions  

SciTech Connect

The excitation functions of elastic and quasielastic scattering at backward angles are measured for the systems 16O + 152Sm , 6,7Li + 208Pb. The barrier distributions are extracted from these measured excitation functions and compared with the corresponding fusion barrier distributions. Except some details, the barrier distributions derived from the data of fusion and elastic/quasielastic scattering are almost the same for the tightly bound reaction systems. For the reaction systems with weakly bound projectile, the barrier distributions extracted from quasielastic scattering are obviously different the fusion barrier distributions. However, the barrier distributions extracted from the excitation functions of the quasielastic scattering plus breakup are almost the same as the one extracted from the complete fusion data. This result means that barrier distribution not only bears the information of nuclear structures but also contains the knowledge of reaction mechanisms. In addition, the measured barrier distribution of 32S + 96Zr is flat and extends to lower energy due to the coupling of neutron transfer with positive Q-values, which will result in a significant enhancement effusion cross sections at the subbarrier energies. However, our results show that the complete fusion of the weakly bound projectile with heavy target is suppressed at the above barrier energies as compared with the model predictions.

Lin, C. J.; Zhang, H. Q.; Yang, F.; Ruan, M.; Liu, Z. H.; Wu, X. K.; Zhou, P.; Zhang, C. L.; Zhang, G. L.; An, G. P.; Jia, H. M.; Xu, X. X. [China Institute of Atomic Energy, P.O. Box 275 (10), Beijing 102413 (China)

2006-11-02

321

Breakup structure of two-phase jets with various momentum flux from a porous injector  

NASA Astrophysics Data System (ADS)

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

Lee, Inchul; Kim, Dohun; Koo, Jaye

2014-02-01

322

Energy enhancement for deuteron beam fast ignition of a precompressed inertial confinement fusion target  

NASA Astrophysics Data System (ADS)

Fast Ignition (FI) is recognized as a potentially promising approach to achieve the high-energy-gain target performance needed for commercial inertial confinement fusion. Here we consider deuteron beam driven FI which provides not only the "hot spot" ignition spark, but also extra "bonus" fusion energy through reactions in the target. In this study, we estimate the impact of the added deposition energy due to the fusion reactions occurring, based on calculations using a modified energy multiplication factor Fc. The deuteron beam energy deposition range and time are also evaluated in order to estimate the desired deuteron initial energy. It is shown that an average of 30% extra energy can be gained from deuterons with 1 MeV initial energy and 12% from deuterons with 3 MeV initial energy. These results indicate that the energy benefit of this approach could be significant, but a much more comprehensive calculation is needed to realize a full 3D design for realistic experimental studies.

Yang, Xiaoling; Miley, George H.; Flippo, Kirk A.; Hora, Heinrich

2011-03-01

323

Energy enhancement for deuteron beam fast ignition of a precompressed inertial confinement fusion target  

SciTech Connect

Fast Ignition (FI) is recognized as a potentially promising approach to achieve the high-energy-gain target performance needed for commercial inertial confinement fusion. Here we consider deuteron beam driven FI which provides not only the 'hot spot' ignition spark, but also extra ''bonus'' fusion energy through reactions in the target. In this study, we estimate the impact of the added deposition energy due to the fusion reactions occurring, based on calculations using a modified energy multiplication factor F{sub c}. The deuteron beam energy deposition range and time are also evaluated in order to estimate the desired deuteron initial energy. It is shown that an average of 30% extra energy can be gained from deuterons with 1 MeV initial energy and 12% from deuterons with 3 MeV initial energy. These results indicate that the energy benefit of this approach could be significant, but a much more comprehensive calculation is needed to realize a full 3D design for realistic experimental studies.

Yang Xiaoling; Miley, George H. [Department of Nuclear, Plasma and Radiological Engineering, University of Illinois, Urbana, Illinois 61801 (United States); Flippo, Kirk A. [P-24 Plasma Physics, Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Hora, Heinrich [University of New South Wales, Sydney 2052 (Australia)

2011-03-15

324

Mechanical behavior of tungsten shaped charge liner materials  

SciTech Connect

Radiographs of jets produced by shaped charges with tungsten liners have documented both ductile and brittle breakup behavior. The relationships between the varying breakup behavior of tungsten shaped charge jets and metallurgical characteristics and/or mechanical behavior of the liner are not understood. In this paper the mechanical behavior of warm-forged and chemical-vapor-deposition (CVD) tungsten is discussed relative to the typical deformation history of an element of liner material which becomes part of the jet. The analyses suggest the following: (1) tungsten liner material is damaged, or possibly pulverized, during shock loading at the high-explosive detonation front; (2) pulverized material is consolidated in the convergence zone under conditions of high pressure, and (3) variations in observed breakup behavior of tungsten may be related to high temperature embrittlement. The low temperature ductile-brittle transition temperature of tungsten (DBTT) is not believed to be directly related to observed variations in break-up behavior of jets.

Lassila, D.H.

1993-08-01

325

Measuring the polarization of a rapidly precessing deuteron beam  

NASA Astrophysics Data System (ADS)

This paper describes a time-marking system that enables a measurement of the in-plane (horizontal) polarization of a 0.97-GeV/c deuteron beam circulating in the Cooler Synchrotron (COSY) at the Forschungszentrum Jülich. The clock time of each polarimeter event is used to unfold the 120-kHz spin precession and assign events to bins according to the direction of the horizontal polarization. After accumulation for one or more seconds, the down-up scattering asymmetry can be calculated for each direction and matched to a sinusoidal function whose magnitude is proportional to the horizontal polarization. This requires prior knowledge of the spin tune or polarization precession rate. An initial estimate is refined by resorting the events as the spin tune is adjusted across a narrow range and searching for the maximum polarization magnitude. The result is biased toward polarization values that are too large, in part because of statistical fluctuations but also because sinusoidal fits to even random data will produce sizable magnitudes when the phase is left free to vary. An analysis procedure is described that matches the time dependence of the horizontal polarization to templates based on emittance-driven polarization loss while correcting for the positive bias. This information will be used to study ways to extend the horizontal polarization lifetime by correcting spin tune spread using ring sextupole fields and thereby to support the feasibility of searching for an intrinsic electric dipole moment using polarized beams in a storage ring. This paper is a combined effort of the Storage Ring EDM collaboration and the JEDI collaboration.

Bagdasarian, Z.; Bertelli, S.; Chiladze, D.; Ciullo, G.; Dietrich, J.; Dymov, S.; Eversmann, D.; Fanourakis, G.; Gaisser, M.; Gebel, R.; Gou, B.; Guidoboni, G.; Hejny, V.; Kacharava, A.; Kamerdzhiev, V.; Lehrach, A.; Lenisa, P.; Lorentz, B.; Magallanes, L.; Maier, R.; Mchedlishvili, D.; Morse, W. M.; Nass, A.; Oellers, D.; Pesce, A.; Prasuhn, D.; Pretz, J.; Rathmann, F.; Shmakova, V.; Semertzidis, Y. K.; Stephenson, E. J.; Stockhorst, H.; Ströher, H.; Talman, R.; Thörngren Engblom, P.; Valdau, Yu.; Weidemann, C.; Wüstner, P.

2014-05-01

326

The root mean square radius of the deuteron and the nonlocality of the nucleon-nucleon interaction  

Microsoft Academic Search

It is shown that the inclusion of a nonlocal component with an optimum strength at short to medium distances in a deuteron potential model would significantly change the value of the root mean square radius of the deuteron without changing the asymptotic normalization. This proposes a remedy for the inconsistency shown by Klarsfeld et al. between the empirical lines which

Mustafa M. Mustafa; El-Shazli M. Hassan

1989-01-01

327

The Use of Satellite Imagery for Monitoring Ice Break-up along the Mackenzie River, N.W.T  

Microsoft Academic Search

The usefulness of satellite imagery for providing comprehensive infor- mation concerning break-up of river ice is discussed. For the years 1975-77, dates of break-up along the Mackenzie River derived from satellite images correlated well with the dates noted at six ground stations in the valley. It is suggested that satellite imagery could also be used to study ice break-up along

B. DEY; H. MOORE; A. F. GREGORY

328

Dominant deuteron acceleration with a high-intensity laser for isotope production and neutron generation  

SciTech Connect

Experiments on the interaction of an ultra-short pulse laser with heavy-water, ice-covered copper targets, at an intensity of 2 Multiplication-Sign 10{sup 19} W/cm{sup 2}, were performed demonstrating the generation of a 'pure' deuteron beam with a divergence of 20 Degree-Sign , maximum energy of 8 MeV, and a total of 3 Multiplication-Sign 10{sup 11} deuterons with energy above 1 MeV-equivalent to a conversion efficiency of 1.5%{+-} 0.2%. Subsequent experiments on irradiation of a {sup 10}B sample with deuterons and neutron generation from d-d reactions in a pitcher-catcher geometry, resulted in the production of {approx}10{sup 6} atoms of the positron emitter {sup 11}C and a neutron flux of (4{+-}1) Multiplication-Sign 10{sup 5} neutrons/sterad, respectively.

Maksimchuk, A.; Raymond, A.; Yu, F.; Dollar, F.; Willingale, L.; Zulick, C.; Krushelnick, K. [Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Michigan 48109 (United States)] [Center for Ultrafast Optical Science, University of Michigan, Ann Arbor, Michigan 48109 (United States); Petrov, G. M.; Davis, J. [Naval Research Laboratory, Plasma Physics Division, Washington, DC 20375 (United States)] [Naval Research Laboratory, Plasma Physics Division, Washington, DC 20375 (United States)

2013-05-13

329

Neutron-Induced Deuteron Production from Light-Nuclei at 800 Mev  

E-print Network

FHYSICAL REVIE% C VOLUME 17, N UMBER 5 1%I A Y I 9 7 8 Neutron-induced deuteron production from light nuclei at 800 MeV* P. J. Riley, C. W. Bjork, t and C. R. Newsom University of Texas, Austin, Texas 78712 R. A. Kenefick, M. L. Evans, ~ G... Y et al. 80- 60- DEUTERONS FROM 800 MeV fi + ' Li 16, Li 40-0 20- JD QM 80- ~ & 60- o 40- O', Li 16', Li ~$r='~ "i~A~t 20- ~ ~ ~ I a l i I 1200 I 400 l600 I800 I200 Pd(M eV/c) l400 I600 l800 FIG. 1. Deuteron spectra from...

Riley, P. J.; Bjork, C. W.; Newsom, C. R.; Kenefick, R. A.; Evans, M. L.; Glass, G.; Hiebert, John C.; Jain, M.; Northcliffe, L. C.; Bonner, BE; Simmons, J. E.; Stein, N.; Cassapakis, C. G.

1978-01-01

330

Dominant deuteron acceleration with a high-intensity laser for isotope production and neutron generation  

NASA Astrophysics Data System (ADS)

Experiments on the interaction of an ultra-short pulse laser with heavy-water, ice-covered copper targets, at an intensity of 2×1019 W/cm2, were performed demonstrating the generation of a "pure" deuteron beam with a divergence of 20°, maximum energy of 8 MeV, and a total of 3×1011 deuterons with energy above 1 MeV—equivalent to a conversion efficiency of 1.5% ± 0.2%. Subsequent experiments on irradiation of a B10 sample with deuterons and neutron generation from d-d reactions in a pitcher-catcher geometry, resulted in the production of ˜106 atoms of the positron emitter C11 and a neutron flux of (4±1)×105 neutrons/sterad, respectively.

Maksimchuk, A.; Raymond, A.; Yu, F.; Petrov, G. M.; Dollar, F.; Willingale, L.; Zulick, C.; Davis, J.; Krushelnick, K.

2013-05-01

331

Final-state interactions in deep-inelastic scattering from a tensor polarized deuteron target  

E-print Network

Deep-inelastic scattering (DIS) from a tensor polarized deuteron is sensitive to possible non-nucleonic components of the deuteron wave function. To accurately estimate the size of the nucleonic contribution, final-state interactions (FSIs) need to be accounted for in calculations. We outline a model that, based on the diffractive nature of the effective hadron-nucleon interaction, uses the generalized eikonal approximation to model the FSIs in the resonance region, taking into account the proton-neutron component of the deuteron. The calculation uses a factorized model with a basis of three resonances with mass $W0.2$, but the overall size of $A_{zz}$ remains small. For tagged spectator DIS, FSIs effects are largest at spectator momenta around 300 MeV and for forward spectator angles.

Cosyn, Wim

2014-01-01

332

Final-state interactions in deep-inelastic scattering from a tensor polarized deuteron target  

E-print Network

Deep-inelastic scattering (DIS) from a tensor polarized deuteron is sensitive to possible non-nucleonic components of the deuteron wave function. To accurately estimate the size of the nucleonic contribution, final-state interactions (FSIs) need to be accounted for in calculations. We outline a model that, based on the diffractive nature of the effective hadron-nucleon interaction, uses the generalized eikonal approximation to model the FSIs in the resonance region, taking into account the proton-neutron component of the deuteron. The calculation uses a factorized model with a basis of three resonances with mass $W0.2$, but the overall size of $A_{zz}$ remains small. For tagged spectator DIS, FSIs effects are largest at spectator momenta around 300 MeV and for forward spectator angles.

Wim Cosyn; Misak Sargsian

2014-07-07

333

Deformation and breakup of a liquid droplet past a solid circular cylinder: A lattice Boltzmann study  

NASA Astrophysics Data System (ADS)

In this paper, we present a numerical study on the deformation and breakup behavior of liquid droplet past a solid circular cylinder by using an improved interparticle-potential lattice Boltzmann method. The effects of the eccentric ratio ?, viscosity ratio ? between the droplet and the surrounding fluid, surface wettability, and Bond number (Bo) on the dynamic behavior of the liquid droplet are considered. The parameter ? represents the degree that the solid cylinder deviates from the center line, and Bo is the ratio between the inertial force and capillary force. Numerical results show that there are two typical patterns, i.e., breakup and no breakup, which are greatly influenced by the aforementioned parameters. When ? increases to a critical value ?c, the droplet can pass the circular cylinder without a breakup, otherwise, the breakup phenomenon occurs. The critical eccentric ratio ?c increases significantly with increasing Bo for case with ? >1, while for the case with ? <1, the viscosity effects on the ?c is not obvious when Bo is large. For the breakup case, the amount of deposited liquid on the tip of the circular cylinder is almost unaffected by ?. In addition, the results also show that the viscosity ratio and wettability affect the deformation and breakup process of the droplet. For case with ? <1, the viscosity ratio plays a minor role in the thickness variations of the deposited liquid, which decreases to a nonzero constant eventually; while for ? >1, the increase of the viscosity ratio significantly accelerates the decrease of the deposited liquid, and finally no fluid deposits on the cylinder. In term of the wettability, there occurs continuous gas phase trapped by the wetting droplet, but this does not happen for nonwetting droplet. Besides, for ? <1, the time required to pass the cylinder (tp) decreases monotonically with decreasing contact angle, while a nonmonotonic decrease appears for ? >1. It is also found that tp decreases monotonically with increasing Bo and is less sensitive to ? at a large Bo.

Li, Qiuxiang; Chai, Zhenhua; Shi, Baochang; Liang, Hong

2014-10-01

334

Breakup Reactions and Exclusive Measurements in the {sup 6,7}Li+{sup 144}Sm Systems  

SciTech Connect

The breakup of the projectile-like nuclei in reactions induced by 30 MeV {sup 6}Li and {sup 7}Li beams on a {sup 144}Sm target have been measured through the coincident detection of the in-plane emitted light particles. The primary ion that undergoes breakup has been identified and the physically meaningful variables that characterize the reaction have been obtained on a purely experimental basis. Distributions have been obtained for both the binary emission angle and for the breakup emission angle in the reference frame of the breakup products.

Heimann, D. Martinez; Pacheco, A. J.; Arazi, A.; Figueira, J. M.; Negri, A. E. [Departamento de Fisica-TANDAR, Comision Nacional de Energia Atomica, Av. Gral. Paz 1499, B1650KNA San Martin (Argentina); CONICET, Av. Rivadavia 1917, C1033AAJ Buenos Aires (Argentina); Capurro, O. A.; Carnelli, P.; Fimiani, L.; Grinberg, P.; Marti, G. V.; Testoni, J. E. [Departamento de Fisica-TANDAR, Comision Nacional de Energia Atomica, Av. Gral. Paz 1499, B1650KNA San Martin (Argentina); Monteiro, D. S. [Instituto de Fisica, Universidade Federal Fluminense, Av. Litoranea s/n, Gragoata, Niteroi, R.J., 24210-340 (Brazil); Niello, J. O. Fernandez [Departamento de Fisica-TANDAR, Comision Nacional de Energia Atomica, Av. Gral. Paz 1499, B1650KNA San Martin (Argentina); CONICET, Av. Rivadavia 1917, C1033AAJ Buenos Aires (Argentina); Universidad Nacional de General San Martin, Ayacucho 2197, B1650BWA San Martin (Argentina); Marta, H. D. [Instituto de Fisica, Facultad de Ingenieria, CC 30 Montevideo (Uruguay)

2009-06-03

335

Continental breakup and its effect on MORB chemistry  

NASA Astrophysics Data System (ADS)

The formation and breakup of supercontinents has major influences on the climate, sealevel and the biosphere on a global scale. The question of possible effects of a supercontinent on mantle convection and thus spreading in the ocean basins has been recently addressed by various studies, focused on numerical modelling. These studies predict higher mantle temperatures on the order of 100°C higher due to the effect of 'continental insulation'. This temperature difference would amplify the effects on sealevel and volcanic CO2 output associated with creation of new spreading centres. However, there is as yet no direct geochemical evidence that could confirm or quantify the continental insulation effect. We have sampled 340 fresh glasses from 30 different sites drilled into old oceanic crust (6-170 Ma) and determined their chemical composition using electron microprobe and ICP-MS techniques. The oldest MORB recovered from the Atlantic and Indian Oceans have lower Na72, higher Fe72 than zero-age MORB. If interpreted as the effects of mantle potential temperature, this chemical difference indicates a mantle source hotter by 50-150°C depending on primary melt composition and applied geothermometry. Higher mantle potential temperatures during the Mesozoic are not a global phenomena but instead restricted to the proto-Atlantic and Indian Ocean. Zero-age MORB from the juvenile Red Sea - Gulf of Aden have similar major element compositions, indicating that higher mantle temperatures beneath young ocean basins result from continental insulation. A subset of about 120 samples has been also analysed for trace element composition using laser ablation and solution ICPMS techniques. These samples are representative for our ancient MORB database in terms of age and geological setting. Trace element ratios sensitive to the degree of partial melting or source fertility such as La/Sm, Sm/Yb, La/Yb or (Dy/Yb)N are positively correlated with fractionation corrected Na2O and negatively correlated with fractionation corrected FeOT. Sites that show differences in radiogenic isotope composition from a normal depleted MORB mantle (e.g. oldest sites in the Atlantic) also display some small differences in trace element ratios that incorporate high field strength elements (e.g. Nb/Zr, Ta/Hf or Nb/La) as well as Rb and Ba. Previous studies (e.g. Bodinier et al., 1996) have suggested the possibility of reaction of spinel with small portions of melt in the subcontinental lithosphere forming very small amounts of rutile and phlogopite in the spinel reaction rims. If so, then the isotopic and trace element signal in MORB erupted immediately after breakup could argue for the presence of subcontinental mantle material incorporated in the melting underneath young ocean ridges. We show that thermal insulation of large continents influences the thermal structure of the upper mantle. These thermal anomalies persist for 50-70 Ma after the initiation of spreading, and would influence oceanic crust thickness, ridge depth/sealevel and CO2 output/climate. Our ancient MORB database provides the first systematic insight into mantle temperature, source heterogeneity and melting processes affecting the petrogenesis of MORB during the lifespan of an ocean basin. Bodinier et al. (1996) GCA 60, 545-550.

Brandl, P. A.; Regelous, M.; Beier, C.; Haase, K. M.

2012-12-01

336

Breakup and vaporization of droplets under locally supersonic conditions  

NASA Astrophysics Data System (ADS)

The disruption and vaporization of simulated fuel droplets in an accelerating supersonic flow was examined experimentally in a draw-down supersonic wind tunnel. The droplets achieved supersonic velocities relative to the surrounding air to give relative Mach numbers of up to 1.8 and Weber numbers of up to 300. Mono-disperse, 100 ?m-diameter fluid droplets were generated using a droplet-on-demand generator upstream of the tunnel entrance. Direct close-up single- and multiple-exposure imaging was used to examine the features of droplet breakup and to determine the droplet velocities. Laser-induced fluorescence (LIF) imaging of the disrupting droplets was performed using acetone fluorescence to determine the dispersion of the expelled vapor. Three test liquids were employed: 2-propanol and tetraethylene glycol dimethyl ether as non-volatile fluids and a 50/50 hexanol-pentane mixture (Hex-Pen 50/50). The vapor pressure of the Hex-Pen 50/50 was sufficiently high to cause the droplet fluid to potentially become superheated in the decreased static pressure of the supersonic stream. The dynamics for 2-propanol and Hex-Pen 50/50 droplets were similar up to the point of disruption, which occurred more rapidly for the more volatile Hex-Pen 50/50. A 1D dynamic droplet model was developed to provide a first estimate of the expected droplet acceleration and velocity. The actual droplet velocities were in reasonable agreement with the model up to the point at which significant droplet disruption and mass loss commenced. The droplet deformation and breakup patterns for these supersonic flow conditions can be classified into four different flow regions characterized by changes in the Weber number with downstream distance as the droplets accelerate, however, those flow regimes and Weber number ranges were different than those seen for droplets disrupting in shock tubes. The disruption patterns were seen to be generally similar for the different fluids, though droplet disruption occurred more rapidly for the more volatile fluid. LIF imaging established the extent of the dispersion of the expelled vapor. Examination of the vapor clouds surrounding the droplets suggests that Hex-Pen 50/50 droplets had a greater rate of vaporization than 2-propanol droplets starting at approximately 2 mm downstream of the nozzle throat, where the air static pressure became lower than the liquid vapor pressure. This suggests that droplet superheating can have an effect on the extent and rate of droplet vaporization under locally supersonic conditions. The degree of vaporization for Hex-Pen 50/50 was approximately 1.3 times greater than that of the non-volatile fluids over all downstream distances in the supersonic flow.

Kim, YoungJun; Hermanson, James C.

2012-07-01

337

Pre-breakup age of East Greenland Ridge strata  

NASA Astrophysics Data System (ADS)

The East Greenland Ridge (EGR) is a submarine elevation that juts out from the Northeast Greenland shelf, separating the modern Boreas Basin in north from the Greenland Basin in south. The EGR strikes roughly northwest-southeast and lies almost perpendicular to the Mohns Spreading Ridge and sub-parallel to the Knipovich Spreading Ridge. The EGR is about 320 km long and includes several en-echelon elongated crests. The flanks on either side of the EGR are generally high and steep, with escarpments exposing outcropping sub-strata. The EGR has been characterized as a continental sliver. However, this is based on analysis of seismic data only, while no direct evidence has hitherto been published to strengthen this interpretation. In 2012, two up-slope transects on the northeastern lower flank of the EGR were dredged by GEUS and UiT in order to obtain in-situ samples of the outcropping strata. Subsequent work by GEUS on the dredged samples was concentrated on lithological description and age determination of selected rock samples. The selected samples were either fresh and angular, or too soft to have survived long transport, and therefore interpreted to be in-situ or near in-situ (local and limited transported) and representative for the geology of the EGR. Some rock samples of greenish grey, slightly sandy mudstones were dated by palynological analysis to be of Late Triassic (Carnian) age, i.e. to pre-date the onset of seafloor spreading in this part of the Northeast Atlantic Ocean by more than 150 ma years. Notably, no basalts were dredged, which further supports the interpretation that the strata overlying the basement of the EGR is composed of pre-breakup sediments, and thus strengthen the characterization of the EGR as a continental sliver.

Nielsen, Tove; Bjerager, Morten; Lindström, Sofie; Nøhr-Hansen, Henrik; Lander Rasmussen, Tine

2014-05-01

338

Neutron Irradiation Using A Deuteron-Deuteron (D-D) Fusion Source: Benefits for 40Ar/39Ar Dating  

NASA Astrophysics Data System (ADS)

Irradiation of samples for 40Ar/39Ar dating, traditionally achieved in a fission reactor, carries the necessary evils of recoil, interference corrections, radiological concerns, and lengthy turnaround time. Alternative high-flux neutron sources with appropriate energies (1-6 MeV) to drive the 39K(n,p)39Ar reaction have been little explored. The deuteron-deuteron (D-D) fusion reaction D(d,n)3He, which can produce essentially monoenergetic 2.45 MeV neutrons, has been achievable for decades albeit with neutron fluxes far too low to be of interest for 40Ar/39Ar dating. D-D neutrons at 2.45 MeV are in many ways ideal for 40Ar/39Ar dating and recent developments in fusion research foreshadow the realization of adequately high neutron fluxes. A toroidal geometry plasma source with axial, self-loading target and central sample placement appears especially promising. Modeling argon isotope production from K, Ca, and Cl shows reductions in all unwanted reaction rates relative to a fission spectrum. Production of 36Ar and 38Ar from Ca and 37Ar from K are negligible from 2.45 MeV neutrons. The production ratios 40Ar/39Ar and 38Ar/39Ar from K and 39Ar/37Ar from Ca are reduced by two, four, and one order(s) of magnitude respectively compared with their production rates in a fission spectrum, reducing these conventionally important interference corrections to the point of negligibility. Additionally, the 24Al(n,? )24Na reaction, which has important radiological consequences due to the ? - activity of 24Na, is essentially eliminated, allowing safer/quicker handling of samples irradiated in Al containers. Eliminating higher energy neutrons, unavoidable in a fission spectrum, also reduces the recoil energy, hence recoil distance, of 39Ar and 37Ar atoms produced chiefly from K and Ca respectively. With fission spectrum neutrons, 39Ar recoil severely limits the applicability of the 40Ar/39Ar method to fine-grained materials such as clay minerals. Modeling of recoil effects using the SRIM ion transport code reveals significant benefits of D-D neutrons in reducing recoil effects. For example, in 1 micron diameter illite crystals, fission spectrum neutrons produce 39Ar with a mean recoil energy of 177 KeV, resulting in ˜17% loss of 39Ar by displacement from the crystals. In contrast, D-D neutrons produce 39Ar with a mean recoil energy of 30 KeV, resulting in only ˜3% loss. Thus, irradiation by D-D neutrons will significantly broaden the scope of problems uniquely addressable by 40Ar/39Ar methods.

Renne, P. R.; Knight, K. B.; Nomade, S.; Leung, K.; Lou, T.

2003-12-01

339

Excitation of giant monopole resonance in 208Pb and 116Sn using inelastic deuteron scattering  

NASA Astrophysics Data System (ADS)

The excitation of the isoscalar giant monopole resonance (ISGMR) in 208Pb and 116Sn has been investigated using small-angle (including 0°) inelastic scattering of 100 MeV/u deuteron and multipole-decomposition analysis (MDA). The extracted strength distributions agree well with those from inelastic scattering of 100 MeV/u ? particles. These measurements establish deuteron inelastic scattering at Ed˜100 MeV/u as a suitable probe for extraction of the ISGMR strength with MDA, making feasible the investigation of this resonance in radioactive isotopes in inverse kinematics.

Patel, D.; Garg, U.; Itoh, M.; Akimune, H.; Berg, G. P. A.; Fujiwara, M.; Harakeh, M. N.; Iwamoto, C.; Kawabata, T.; Kawase, K.; Matta, J. T.; Murakami, T.; Okamoto, A.; Sako, T.; Schlax, K. W.; Takahashi, F.; White, M.; Yosoi, M.

2014-07-01

340

Final-state interactions in inclusive deep-inelastic scattering from the deuteron  

E-print Network

We explore the role of final-state interactions (FSI) in inclusive deep-inelastic scattering from the deuteron. Relating the inclusive cross section to the deuteron forward virtual Compton scattering amplitude, a general formula for the FSI contribution is derived in the generalized eikonal approximation, utilizing the diffractive nature of the effective hadron-nucleon interaction. The calculation uses a factorized model with a basis of three resonances with mass $Wspace constraints. The off-shell rescattering contributes at $x \\gtrsim 0.8$ and is taken as an uncertainty on the on-shell result.

W. Cosyn; W. Melnitchouk; M. Sargsian

2013-11-14

341

Incoherent pion photoproduction on the deuteron with polarization observables I: Formal expressions  

E-print Network

Formal expressions are developed for the general five-fold differential cross section of incoherent $\\pi$-photoproduction on the deuteron including beam and target polarization. The polarization observables of the cross section are described by various beam, target and beam-target asymmetries for polarized photons and/or polarized deuterons. They are given as bilinear hermitean forms in the reaction matrix elements divided by the unpolarized cross section. In addition, the corresponding observables for the semi-exclusive reaction $\\vec d(\\vec \\gamma,\\pi)NN$ are also given.

H. Arenhoevel; A. Fix

2005-06-06

342

Measurement of the spin-dependent structure function g1(x) of the deuteron  

Microsoft Academic Search

We report on the first measurement of the spin-dependent structure function g1d of the deuteron in the deep inelastic scattering of polarised muons off polarised deuterons, in the kinematical range 0.006

B. Adeva; S. Ahmad; A. Arvidson; B. Badelek; M. K. Ballintijn; G. Bardin; G. Baum; P. Berglund; L. Betev; I. G. Bird; R. Birsa; P. Björkholm; B. E. Bonner; N R De Botton; M. Boutemeur; Franco Bradamante; A. Bressan; A. Brüll; J. Buchanan; S. Bültmann; E. Burtin; C. Cavata; J. P. Chen; J. Clement; M. Clocchiatti; M. D. Corcoran; D. Crabb; J. Cranshaw; T Çuhadar-Dönszelmann; S. dalla Torre; R. van Dantzig; D. Day; S K Dhawan; C M Dulya; A. Dyring; S. Eichblatt; Jean-Claude Faivre; D. Fasching; F. Feinstein; C. Fernandez; Bernard Frois; C. Garabatos; J. A. Garzon; L. Gatignon; T. Gaussiran; M A Giorgi; E. von Goeler; Igor A Goloutvin; A. Gomez; G. Gracia; M. Grosse Perdekamp; W. Grübler; D. von Harrach; T. Hasegawa; P. Hautle; N. Hayashi; C. A. Heusch; N. Horikawa; V. W. Hughes; G. Igo; S. Ishimoto; T. Iwata; M. de Jong; E M Kabuss; R. Kaiser; A G Karev; H. J. Kessler; T. J. Ketel; I. Kiryushin; A. Kishi; Yu. Kisselev; L. Klostermann; W. Knop; V G Krivokhizhin; V V Kukhtin; J. Kyynäräinen; M. Lamanna; U. Landgraf; K. Lau; T. Layda; F. Lehar; A. de Lesquen; J. Lichtenstadt; T. Lindqvist; M. Litmaath; S. Lopez-Ponte; M Loewe; A. Magnon; G. K. Mallot; F. Marie; A. Martin; J. Martino; B W Mayes; J. S. McCarthy; G. van Middelkoop; D. Miller; J. Mitchell; K. Mori; J H Moromisato; G. S. Mutchler; J P Nassalski; Lutz Naumann; B S Neganov; T. O. Niinikoski; J. E. J. Oberski; S. Okumi; Aldo L Penzo; G. Perez; F. Perrot-Kunne; D. Peshekhonov; R. Piegaia; L. Pinsky; S K Platchkov; M. Plo; D. Pose; H. Postma; T. Pussieux; J. Pyrlik; Jean Michel Rieubland; A. Rijllart; J. B. Roberts; M. Rodriguez; Ewa Rondio; Leszek Ropelewski; A. Rosado; I. Sabo; J. Saborido; G. Salvato; A. Sandacz; D. Sanders; I A Savin; P. Schiavon; P. Schüler; R E Segel; R. Seitz; S. Sergeev; F. Sever; P. Shanahan; G. Smirnov; A. Staude; A. Steinmetz; H B Stuhrmann; K. M. Teichert; F. Tessarotto; W. Thiel; S. Trentalange; Yu Tzamouranis; M. Velasco; J. Vogt; Rüdiger Voss; R. Weinstein; C. Whitten; R. Windmolders; W. Wislicki; A. Witzmann; A. Yañez; N. I. Zamiatin; A. M. Zanetti

1993-01-01

343

Measurement of (anti)deuteron and (anti)proton production in DIS at HERA  

E-print Network

The first observation of (anti)deuterons in deep inelastic scattering at HERA has been made with the ZEUS detector at a centre-of-mass energy of 300--318 GeV using an integrated luminosity of 120 pb-1. The measurement was performed in the central rapidity region for transverse momentum per unit of mass in the range 0.3rates have been extracted and interpreted in terms of the coalescence model. The (anti)deuteron production yield is smaller than the (anti)proton yield by approximately three orders of magnitude, consistent with the world measurements.

ZEUS Collaboration; S. Chekanov

2007-05-25

344

Study By Spin Tracking of A Storage Ring For Deuteron Electric Dipole Moment  

NASA Astrophysics Data System (ADS)

Spin tracking of polarized deuterons for a proposed experiment to measure a possible Electric Dipole Moment (EDM) of the deuteron was done by using the codes UAL and SPINK. In the experiment the direction of spin polarization will be frozen using crossed electric and magnetic fields. Systematics, in particular the effects of non-linearities of the lattice on a beam with finite emittance and energy spread, have been extensively simulated and the effect of sextuple corrections to increase the spin coherence time has been studied.

Lin, F.; Malitsky, N. D.; Luccio, A. U.; Morse, W. M.; Semertzidis, Y. K.; Onderwater, C. J. G.; Orlov, Y. F.

2009-08-01

345

Breakup of spiral waves caused by radial dynamics: Eckhaus and finite wavenumber instabilities  

NASA Astrophysics Data System (ADS)

In this paper, we link numerical observations of spiral breakup to a stability analysis of simple rotating spirals. We review the phenomenology of spiral breakup, important applications in pattern formation and the state of the art in numerical stability analysis of spirals. A strategy for the latter procedure is suggested. Phenomenologically, spiral breakup can occur near the centre of rotation ('core breakup') or far away from it ('far-field breakup'). It may be accompanied by instabilities of the spiral core in particular spiral meandering that affect also the stability of waves in the far-field, because an unstable core acts as a moving source and introduces a (nonlinear) Doppler effect. In general, breakup of non-meandering spirals is related to an absolute instability of the planar wavetrain with the same wave number. To simplify the stability problem, we consider a one-dimensional cut ('1D spiral') with a fixed core position in simulations and compare the results with a stability analysis of planar wavetrains. These 1D spirals approximate the radial dynamics of non-meandering 2D spirals. To fully account for instabilities of 1D spirals, it is not sufficient to compute the direction of propagation of the unstable modes of the wavetrains, one also needs to compute the so-called absolute spectrum of these wavetrains. This allows us to decide whether the instability is of convective or absolute nature. Only the latter case implies an instability of spirals in finite domains. We carry out this programme for the case of core breakup in an excitable reaction diffusion system, the modified Barkley model. Our analysis yields that core breakup can result from the absolute variant of a novel finite wavenumber instability of the radial dynamics where the critical perturbations are transported towards the core. From these results, we can confirm that a simple spiral breaks up if the wavetrain in the far-field is absolutely unstable. The central new result is the discovery of respective convective and absolute instabilities of wavetrains connected with modes of finite wavenumber that propagate in the direction opposite to the wavetrain. Hence, in spirals, perturbations are moving inward and core breakup becomes possible even in the absence of meandering. EHPRG Award Lecture.

Bär, Markus; Brusch, Lutz

2004-01-01

346

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

NASA Astrophysics Data System (ADS)

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.

Bai, Fuqiang; Diao, Hai; Zhang, Mengzheng; Chang, Qing; Wang, Endong; Du, Qing

2014-10-01

347

Exclusive Measurements of Breakup Reactions in the {sup 7}Li+{sup 144}Sm System  

SciTech Connect

Breakup reactions induced by a 30 MeV {sup 7}Li beam on a {sup 144}Sm target were measured through the coincident detection of the light particles emitted in the reaction plane. The emphasis of the measurements and data analysis was placed in the complete characterization of the reaction by means of the identification of the breakup products and the experimental extraction of the physically relevant magnitudes. The coincident yield of the emitted light particles was compared with the results of kinematical calculations that were done assuming different distributions for these magnitudes and taking into account the geometric response of the detection system. The results of this comparison indicate in all cases a clear dominance of a process compatible with the breakup of {sup 6}Li through the 3{sup +} resonant state at 2.186 MeV following one-neutron transfer from the projectile to the target, over the breakup of the projectile itself. Relative cross sections as a function of the emission angle of the {sup 6}Li and the in-plane anisotropy of the subsequent emission of breakup products were extracted from the data.

Heimann, D. Martinez; Pacheco, A. J.; Arazi, A.; Figueira, J. M.; Negri, A. [Departamento de Fisica-TANDAR, Comision Nacional de Energia Atomica, Av. Gral. Paz 1499, BKNA1650 San Martin (Argentina); CONICET, Av. Rivadavia 1917, C1033AAJ Buenos Aires (Argentina); Capurro, O. A.; Carnelli, P.; Fimiani, L.; Grinberg, P.; Marti, G. V.; Testoni, J. E. [Departamento de Fisica-TANDAR, Comision Nacional de Energia Atomica, Av. Gral. Paz 1499, BKNA1650 San Martin (Argentina); Monteiro, D. S. [Instituto de Fisica, Universidade Federal Fluminense, Av. Litoranea s/n, Gragoata, Niteroi, R.J., 24210-340 (Brazil); Niello, J. O. Fernandez [Departamento de Fisica-TANDAR, Comision Nacional de Energia Atomica, Av. Gral. Paz 1499, BKNA1650 San Martin (Argentina); CONICET, Av. Rivadavia 1917, C1033AAJ Buenos Aires (Argentina); Universidad Nacional de General San Martin, Ayacucho 2197, 1650 San Martin (Argentina); Marta, H. D. [Instituto de Fisica, Facultad de Ingenieria, CC 30 Montevideo (Uruguay)

2009-03-04

348

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

E-print Network

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.

Liu, Quan-Xing

2007-01-01

349

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

NASA Technical Reports Server (NTRS)

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.

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

2010-01-01

350

Estimation of the nuclear distortion in the Coulomb breakup of 6Li into ? + d in the field of 208Pb ion  

NASA Astrophysics Data System (ADS)

In this article the results of the evaluation of the contribution of nuclear disintegration, based on the basis of diffraction theory in the 208Pb(6Li, ?d)208Pb Coulomb breakup at an energy of 156 MeV is presented. Comparison of the results of the calculation with the experimental data of Kiener et al. [Phys. Rev. C 44, 2195 (1991)] gives evidence for the dominance of the Coulomb dissociation mechanism and contribution of nuclear distortion, but essentially smaller than the value reported byHammache et al. [Phys. Rev. C 82, 065803 (2010)] and Sümmerer [Prog. Part. Nucl. Phys. 66, 298 (2011)].

Irgaziev, B. F.

2014-04-01

351

Local spring warming drives earlier river-ice breakup in a large Arctic delta  

NASA Astrophysics Data System (ADS)

rivers strongly affect the Arctic Ocean and their vast lake-rich deltas. Their discharges may be increasing because of an intensifying hydrological cycle driven by warming climate. We show that a previously unexplained trend toward earlier ice breakup in the Mackenzie River Delta is little affected by winter warming during the period of river-ice growth and is unaffected by river discharge, but unexpectedly is strongly related to local spring warming during the period of river-ice melt. These results are statistically linked to declining winter snowfall that was not expected because of an intensifying Arctic hydrological cycle. Earlier ice breakup is expected to cause declining water level peaks that will reduce off-channel flows through the lake-rich delta before river waters enter the ocean. Thus, local spring warming with unexpected snowfall declines, rather than warmer winters, can drive earlier ice breakup in large Arctic rivers and biogeochemical changes in their river-ocean interface.

Lesack, Lance F. W.; Marsh, Philip; Hicks, Faye E.; Forbes, Donald L.

2014-03-01

352

Formation of Long Tails during Breakup of Oil Droplets Mixed with Dispersants in Locally Isotropic Turbulence  

NASA Astrophysics Data System (ADS)

This study investigates experimentally, the effects of adding dispersants on the breakup of crude oil droplets in turbulent flows during oceanic spills. The current measurements are performed in a nearly homogeneous and isotropic turbulence facility, the central portion of which is characterized using 2-D PIV. Sample crude oil from Alaska National Slope is mixed with dispersant COREXIT 9527 and injected into the central portion of the turbulent facility. High speed, in-line digital holographic cinematography is utilized to visualize the breakup of droplets at high spatial and temporal resolution. We observe that, in some cases, after the droplet breaks up, the elongated portion of the droplet does not recoil, leaving an elongated tail, probably due to the low local surface tension. At high dispersant to oil ratios, extremely thin tails extend from the droplet, and are stretched by the flow. Breakup of these thin threads produces very small oil droplets, a desired effect during cleanup of oil spill.

Gopalan, Balaji; Katz, Joseph

2008-11-01

353

Imaging and photometry of comet C/1999 S4 (LINEAR) before perihelion and after breakup.  

PubMed

We analyzed photometric measurements and images of comet C/LINEAR before perihelion and after its breakup. Results from our photometry data include a lower limit of 0.44 kilometer for the radius of the nucleus before breakup, and a determination that it was depleted in carbon-chain molecules relative to most other comets. Our imaging and modeling results, which include a constraint on the rotational state of the nucleus, indicate that the disintegration likely started on 18 or 19 July 2000. The total mass detectable in the dust tail after the breakup was 3 x 10(8) kilograms, comparable to one of the fragments in the Hubble Space Telescope images; we therefore infer that most of the comet's original mass is hidden in remnants between 1 millimeter and 50 meters in diameter. PMID:11359005

Farnham, T L; Schleicher, D G; Woodney, L M; Birch, P V; Eberhardy, C A; Levy, L

2001-05-18

354

Effects of thermal quenching on the breakup of pyroclasts  

NASA Astrophysics Data System (ADS)

It is often assumed that magma fragments when it contacts water. Obsidian chips and glass spheres crack when quenched. Vesicular pyroclasts are made of similar glass, so thermal quenching may cause them to break more easily. We performed a set of experiments on air fall pumice from Medicine Lake, California. Density and texture of similar samples are described in Manga et al., Bull Volc 2010. We made "quenched" samples by heating natural pyroclasts to 600 °C, quenching them in water at 21 °C, drying them at 105 °C, and then cooling them to room temperature. We compare these samples with untreated air fall pumice from the same deposit, hereafter referred to as "regular" pumice. We tested whether quenched pumice would 1) shatter more easily in collisions and 2) abrade faster. Our collision experiment methods are described in Dufek et al., Nature Geoscience 2012. Our abrasion experiment methods are described in Manga et al., Bull Volc 2010. We also tested whether individual clasts lose mass upon quenching and whether they increase in effective wet density. Effective wet density is defined as underwater density of a clast when water occupies part of the pore space. Effective wet density, measured as a function of time after immersion, indicates the volume fraction of the pore space that becomes occupied by water. We compare effective wet density of individual clasts pre-quenching with effective wet density after having been quenched, thoroughly dried and then cooled to room temperature. An increase in effective wet density would suggest that bubble walls had been damaged during quenching, allowing water to occupy the pore space faster. We also compare pre-quenching and post-quenching textures using X-Ray Tomography (XRT) and SEM images. Results from collision experiments show no obvious difference between quenched pumice and regular pumice. Quenched pumice abraded more quickly than regular pumice. We find that 1 to 2 % of mass was lost during quenching. Effective 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.

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

2012-12-01

355

Two-body photodisintegration of the deuteron above 1 GeV  

Microsoft Academic Search

One of the central issues in nuclear physics is the identification of clear signatures for quarks in nuclei. A guiding principle in this search is to perform experiments with high energy electromagnetic probes of the simplest nucleus, the deuteron, a system which is particularly amenable to theoretical interpretation. It has long been known that the quark counting rules seem to

R. J. Holt; S. J. Freedman; D. F. Geesaman; R. Gilman; M. C. Green; H. E. Jackson; R. Kowalczyk; C. Marchand; J. Napolitano; J. Nelson

1988-01-01

356

Setup and performance of RHIC for the 2008 run with deuteron-gold collisions.  

SciTech Connect

This year (2008) deuterons and gold ions were collided in the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory (BNL) for the first time since 2003. The setup and performance of the collider for the 2008 run is reviewed with a focus on improvements that have led to an order of magnitude increase in luminosity over that achieved in the 2003 run.

Gardner,C.; Abreu, N.P.; Ahren, L.; Alessi, J.; Bai, M.; et al.

2008-06-23

357

Time Reversal Invariance Violating and Parity Conserving effects in Neutron Deuteron Scattering  

E-print Network

Time reversal invariance violating parity conserving effects for low energy elastic neutron deuteron scattering are calculated for meson exchange and EFT-type of potentials in a Distorted Wave Born Approximation, using realistic hadronic wave functions, obtained by solving three-body Faddeev equations in configuration space.

Young-Ho Song; Rimantas Lazauskas; Vladimir Gudkov

2011-05-06

358

Time reversal invariance violating and parity conserving effects in neutron-deuteron scattering  

Microsoft Academic Search

Time reversal invariance violating and parity conserving effects for low-energy elastic neutron-deuteron scattering are calculated for meson exchange and effective field theory type potentials in a distorted wave-born approximation using realistic hadronic wave functions, obtained by solving three-body Faddeev equations in configuration space.

Young-Ho Song; Rimantas Lazauskas; Vladimir Gudkov

2011-01-01

359

Nucleon Polarizabilities from Deuteron Compton Scattering within a Green's-Function Hybrid Approach  

E-print Network

We examine elastic Compton scattering from the deuteron for photon energies ranging from zero to 100 MeV, using state-of-the-art deuteron wave functions and NN-potentials. Nucleon-nucleon rescattering between emission and absorption of the two photons is treated by Green's functions in order to ensure gauge invariance and the correct Thomson limit. With this Green's-function hybrid approach, we fulfill the low-energy theorem of deuteron Compton scattering and there is no significant dependence on the deuteron wave function used. Concerning the nucleon structure, we use Chiral Effective Field Theory with explicit \\Delta(1232) degrees of freedom within the Small Scale Expansion up to leading-one-loop order. Agreement with available data is good at all energies. Our 2-parameter fit to all elastic $\\gamma d$ data leads to values for the static isoscalar dipole polarizabilities which are in excellent agreement with the isoscalar Baldin sum rule. Taking this value as additional input, we find \\alpha_E^s= (11.3+-0.7(stat)+-0.6(Baldin)) x 10^{-4} fm^3 and \\beta_M^s = (3.2-+0.7(stat)+-0.6(Baldin)) x 10^{-4} fm^3 and conclude by comparison to the proton numbers that neutron and proton polarizabilities are essentially the same.

Robert P. Hildebrandt; Harald W. Griesshammer; Thomas R. Hemmert

2005-12-16

360

Time reversal invariance violating and parity conserving effects in neutron-deuteron scattering  

NASA Astrophysics Data System (ADS)

Time reversal invariance violating and parity conserving effects for low-energy elastic neutron-deuteron scattering are calculated for meson exchange and effective field theory type potentials in a distorted wave-born approximation using realistic hadronic wave functions, obtained by solving three-body Faddeev equations in configuration space.

Song, Young-Ho; Lazauskas, Rimantas; Gudkov, Vladimir

2011-08-01

361

Time Reversal Invariance Violating and Parity Conserving effects in Neutron Deuteron Scattering  

E-print Network

Time reversal invariance violating parity conserving effects for low energy elastic neutron deuteron scattering are calculated for meson exchange and EFT-type of potentials in a Distorted Wave Born Approximation, using realistic hadronic wave functions, obtained by solving three-body Faddeev equations in configuration space.

Song, Young-Ho; Gudkov, Vladimir

2011-01-01

362

Nucleon polarizabilities from deuteron Compton scattering within a Green's function hybrid approach  

NASA Astrophysics Data System (ADS)

We examine elastic Compton scattering from the deuteron for photon energies ranging from zero to 100MeV, using state-of-the-art deuteron wave functions and NN potentials. Nucleon-nucleon rescattering between emission and absorption of the two photons is treated by Green’s functions in order to ensure gauge invariance and the correct Thomson limit. With this Green’s function hybrid approach, we fulfill the low-energy theorem of deuteron Compton scattering and there is no significant dependence on the deuteron wave function used. Concerning the nucleon structure, we use the chiral effective field theory with explicit ?(1232) degrees of freedom within the small-scale expansion up to leading-one-loop order. Agreement with available data is good at all energies. Our 2-parameter fit to all elastic ? d data leads to values for the static isoscalar dipole polarizabilities which are in excellent agreement with the isoscalar Baldin sum rule. Taking this value as additional input, we find ?Es = (11.3±0.7( stat)±0.6( Baldin)±1( theory)).10-4 fm^3 and ?Ms = (3.2±0.7( stat)±0.6( Baldin)±1( theory)).10-4 fm^3 and conclude by comparison to the proton numbers that neutron and proton polarizabilities are the same within rather small errors.

Hildebrandt, R. P.; Grießhammer, H. W.; Hemmert, T. R.

2010-10-01

363

Deuteron-induced reactions generated by intense lasers for PET isotope production  

NASA Astrophysics Data System (ADS)

We investigate the feasibility of using laser accelerated protons/deuterons for positron emission tomography (PET) isotope production by means of the nuclear reactions 11B(p, n) 11C and 10B(d, n) 11C. The second reaction has a positive Q-value and no energy threshold. One can, therefore, make use of the lower energy part of the laser-generated deuterons, which includes the majority of the accelerated deuterons. By assuming that the deuteron spectra are similar to the proton spectra, the 11C produced from the reaction 10B(d, n) 11C is estimated to be 7.4×10 9 per laser-shot at the Titan laser at Lawrence Livermore National Laboratory. Meanwhile a high-repetition table-top laser irradiation is estimated to generate 3.5×10 711C per shot from the same reaction. In terms of the 11C activity, it is about 2×10 4 Bq per shot. If this laser delivers kHz, the activity is integrated to 1 GBq after 3 min. The number is sufficient for the practical application in medical imaging for PET.

Kimura, Sachie; Bonasera, Aldo

2011-05-01

364

Extracting hadron-neutron scattering amplitudes from hadron-proton and hadron-deuteron measurements  

NASA Technical Reports Server (NTRS)

A method is presented for extracting hadron-neutron scattering amplitudes from hadron-proton and hadron-deuteron measurements within the framework of the Glauber approximation. This method, which involves the solution of a linear integral equation, is applied to pn collisions between 15 and 275 GeV/c. Effects arising from inelastic intermediate states are estimated.

Franco, V.

1977-01-01

365

Rescattering effects and two-step process in kaon photoproduction on the deuteron  

E-print Network

Kaon photoproduction on the deuteron is investigated by considering YN and KN rescattering and the two-step process gamma d --> pi NN --> KYN. A strong enhancement in the total cross section is found from the two-step process. YN rescattering has remarkable effects in the inclusive and exclusive cross section, while the effect of KN rescattering is much less important.

A. Salam; K. Miyagawa; H. Arenhoevel; T. Mart; C. Bennhold; W. Gloeckle

2004-11-10

366

Rescattering effects and two-step process in kaon photoproduction on the deuteron  

Microsoft Academic Search

Kaon photoproduction on the deuteron is investigated by considering YN and KN rescattering and the two-step process gamma d --> pi NN --> KYN. A strong enhancement in the total cross section is found from the two-step process. YN rescattering has remarkable effects in the inclusive and exclusive cross section, while the effect of KN rescattering is much less important.

A. Salam; K. Miyagawa; H. Arenhoevel; T. Mart; C. Bennhold; W. Gloeckle

2004-01-01

367

Measurement of tensor analyzing powers in elastic electron deuteron scattering with BLAST  

E-print Network

This work reports a precision measurement of deuteron tensor analyzing powers T20 and T21 at the MIT-Bates Linear Accelerator Center. Data were collected simultaneously over a momentum transfer range of 2:15 to 4:5 fm¡1 ...

Zhang, Chi, Ph. D. Massachusetts Institute of Technology

2006-01-01

368

Reply to comment by Alley et al. on ``Catastrophic ice shelf breakup as the source of Heinrich event icebergs''  

E-print Network

event icebergs'' Christina L. Hulbe Department of Geology, Portland State University, Portland, Oregon breakup as the source of Heinrich event icebergs,'' Paleoceanography, 20, PA1011, doi:10.1029/2004PA001118 breakup as the source of Heinrich event icebergs'' by C. L. Hulbe et al., Paleoceanogra- phy, PA1009 doi

Boyce, C. Kevin

369

Expressions for the threshold current of multipass beam breakup in recirculating linacs from single cavity models  

SciTech Connect

We investigate multipass beam breakup (BBU) in a recirculating linear accelerator in the framework of a single cavity model. We present expressions for the beam breakup threshold current for various situations derived from a perturbative solution of BBU equations. These formulae should serve as a guide to understand the BBU phenomenon for a particular system and also as a tool to estimate the BBU threshold current quickly. Many of the results presented are more general than previous considerations because they include the effects of coupling between the two transverse polarizations in each dipole higher order mode.

Byung C. Yunn

2005-10-01

370

Calculation of Multichannel Reactions in the Four-Nucleon System above Breakup Threshold  

NASA Astrophysics Data System (ADS)

The exact four-body equations of Alt, Grassberger, and Sandhas are solved for neutron-He3 and proton-H3 scattering in the energy regime above the four-nucleon breakup threshold. Cross sections and spin observables for elastic, transfer, charge-exchange, and breakup reactions are calculated using realistic nucleon-nucleon interaction models, including the one with effective many-nucleon forces due to explicit ?-isobar excitation. The experimental data are described reasonably well with only few exceptions such as vector analyzing powers.

Deltuva, A.; Fonseca, A. C.

2014-09-01

371

Breakup of Air Bubbles in Water: Memory and Breakdown of Cylindrical Symmetry  

E-print Network

Using high-speed video, we have studied air bubbles detaching from an underwater nozzle. As a bubble distorts, it forms a thin neck which develops a singular shape as it pinches off. As in other singularities, the minimum neck radius scales with the time until breakup. However, because the air-water interfacial tension does not drive breakup, even small initial cylindrical asymmetries are preserved throughout the collapse. This novel, non-universal singularity retains a memory of the nozzle shape, size and tilt angle. In the last stages, the air appears to tear instead of pinch.

Nathan C. Keim; Peder Moller; Wendy W. Zhang; Sidney R. Nagel

2006-05-26

372

On the breakup of air bubbles in Hele-Shaw cell  

E-print Network

We study the problem of breakup of an air bubble in a Hele-Shaw cell. In particular, we propose some sufficient conditions of breakup of the bubble, and ways to find the contraction points of its parts. We also study regulated contraction of a pair of bubbles (in which the rates of air extraction from the bubbles is controlled), and study various asymptotic questions (such as the asymptotics of contraction of a bubble to a degenerate critical point, and asymptotics of contraction of a small bubble in presence of a big bubble).

Vladimir Entov; Pavel Etingof

2008-04-30

373

Breakup threshold anomaly in the elastic scattering of {sup 6}Li on {sup 27}Al  

SciTech Connect

Elastic scattering of the weakly bound {sup 6}Li on {sup 27}Al was measured at near-barrier energies. The data analysis was performed using a Woods-Saxon shape optical potential and also using the double-folding Sao Paulo potential. The results show the presence of the breakup threshold anomaly (BTA), an anomalous behavior when compared with the scattering of tightly bound nuclei. This behavior is attributed to a repulsive polarization potential produced by the coupling to the continuum breakup states.

Figueira, J. M. [Laboratorio TANDAR, Comision Nacional de Energia Atomica, Av. General Paz 1499, 1650 San Martin, Buenos Aires (Argentina); Departamento de Fisica, FCEyN, Universidad de Buenos Aires, Ciudad Universitaria, Pabellon 1, 1428 Buenos Aires (Argentina); Niello, J. O. Fernandez; Abriola, D.; Arazi, A.; Capurro, O. A.; Barbara, E. de; Marti, G. V.; Heimann, D. Martinez; Negri, A. E.; Pacheco, A. J. [Laboratorio TANDAR, Comision Nacional de Energia Atomica, Av. General Paz 1499, 1650 San Martin, Buenos Aires (Argentina); Padron, I.; Gomes, P. R. S.; Lubian, J.; Correa, T.; Paes, B. [Instituto de Fisica, Universidade Federal Fluminense, Av. Litoranea s/n, Gragoata, Niteroi, R.J., 24210-340 (Brazil)

2007-01-15

374

Breakup magmatism on the North Atlantic Igneous Province: what could we learn about the extension/breakup processes from the Norwegian Margin?  

NASA Astrophysics Data System (ADS)

The early continental breakup and initial seafloor spreading in the northeast Atlantic area was accompanied by widespread intrusive and extrusive volcanism. New and reprocessed seismic reflection allow for detailed seismic volcanostratigraphy interpretation of the breakup complex and sub-basalt sequences. Several distinct volcanic seismic facies units have been identified: (1) Landward Flows, (2) Lava Delta, (3) Inner Flows, (4) Inner Seaward Dipping Reflectors (Inner SDR), (5) Outer High, (6) Outer SDR. Such facies succession represents a typical volcanic rifted margin and defines the extent of the breakup extrusive complex landward of the first magnetic seafloor spreading anomaly. We present an updated map of the volcanic seismic facies units in the northeast Atlantic area based on high-quality geophysical data combined with the newest published and unpublished data. The Norwegian margin shows an along-strike segmentation that seems to be in relation with the margin inheritance. We notice that this segmentation affect also melt production in the area and LCB (lower Crustal Bodies) extent. The lateral variation of LCB thickness could be interpreted as a variation of melt supply during the extension/breakup process which is also controlled by the crustal inheritance. The updated imaging of the sub-basalt facies and the deep crustal mapping provides important constrain on the pre-volcanic basin configuration, margin subsidence history, and the volume of igneous rocks. These constraints lead to a better understanding of the melt supply from the upper mantle and the relationship between tectonic setting and volcanism. The result gives key boundary conditions for understanding the processes forming volcanic margins and constraints on the thermal evolution of associated prospective volcanic basins.

Mansour Abdelmalak, Mohamed; Planke, Sverre; Faleide, Jan Inge; Myklebust, Reidun; Gernigon, Laurent; Horni, Jim; Wong, Po-Wan

2013-04-01

375

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

NASA Astrophysics Data System (ADS)

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 11Li+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.

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

2011-04-01

376

Production of cumulative deuterons and tritons with momenta 0. 6--1. 83 GeV/c  

SciTech Connect

Invariant cross sections were measured at 119/sup 0/ for cumulative production of deuterons and tritons on Be, Al, Cu, Ta nuclei bombarded by protons with energy 10.14 GeV in the previously unstudied range 0.6--1.83 GeV/c of secondary particle momenta. It is shown that invariant cross sections for production of deuterons and tritons from heavy nuclei are well described by the coalescence model. For cross sections for production of deuterons with momenta less than 0.6 GeVxc/sup -1/xnucleon/sup -1/ from Be nuclei, a contribution from some other mechansim (possibly pickup) was observed.

Boyarinov, S.V.; Gerzon, S.A.; Kisele-italic-dieresisv, Y.T.; Leksin, G.A.; Martem'yanov, A.N.; Novikov, V.L.; Seme-dieresisnov, S.V.; Terekhov, Y.V.; Sheinkman, V.A.

1988-04-01

377

Instabilities on a free falling jet under an internal flow breakup mode regime  

Microsoft Academic Search

Instabilities leading to the breakup of low velocity liquid jets are investigated experimentally. Pulsed shadowgraphy was used to measure local quantities on the wavy shape of the jets with an anamorphic imaging setup. Statistical recording is employed to determine the mean characteristics of the instabilities and time-resolved recording is used to follow individual waves along the jet axis. Particular attention

J. B. Blaisot; S. Adeline

2003-01-01

378

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

ERIC Educational Resources Information Center

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…

Gilbert, Steven P.; Sifers, Sarah K.

2011-01-01

379

JET BREAKUP and SPRAY FORMATION in a DIESEL ENGINE James Glimm  

E-print Network

details of the injection system design, including the driving pressure in the nozzle, the nozzle shape, Argonne, IL 60493, USA Abstract The breakup of injected fuel into spray is of key interest to the design of diesel fuel injection spray with the front tracking code FronTier. Our simulation design is set to match

New York at Stoney Brook, State University of

380

Real-Time Characterization of Formation and Breakup of Iridium Clusters in Highly Dealuminated Zeolite Y  

SciTech Connect

The chemistry of formation of iridium clusters from mononuclear iridium diethylene complexes anchored in dealuminated Y zeolite, and their subsequent breakup -- all including changes in the metal-metal, metal-support, and metal-ligand interactions -- is demonstrated by time-resolved EXAFS, XANES, and IR spectroscopy.

Uzun, Alper; Gates, Bruce C. (UCD)

2009-01-15

381

Acatlán Complex, southern Mexico: Record spanning the assembly and breakup of Pangea  

Microsoft Academic Search

New structural, geochronological, and geochemical data from the Acatlán Complex of southern Mexico show that it preserves a complete history of Pangea, from assembly to breakup. Previously interpreted to be a vestige of the Iapetus suture, the Acatlán Complex records a history that can be sequentially linked to the Rheic Ocean, the paleo-Pacific, and the Gulf of Mexico. This record

R. Damian Nance; Brent V. Miller; J. Duncan Keppie; J. Brendan Murphy; Jaroslav Dostal

2006-01-01

382

Breakup of Temperature Inversions in Deep Mountain Valleys: Part I. Observations  

Microsoft Academic Search

The breakup of temperature inversions in the deep mountain valleys of western Colorado has been studied by means of tethered balloon observations of wind and temperature structure on clear weather days in different seasons. Vertical potential temperature structure profiles evolve following one of three patterns. Two of the patterns are special cases of the third pattern, in which inversions are

C. David Whiteman

1982-01-01

383

Breakup of temperature inversions in deep mountain valleys. Part I. Observations  

Microsoft Academic Search

The breakup of temperature inversions in the deep mountain valleys of western Colorado has been studied by means of tethered balloon observations of wind and temperature structure on clear weather days in different seasons. Vertical potential temperature structure profiles evolve following one of three patterns. Two of the patterns are special cases of the third pattern, in which inversions are

C. David Whiteman

1982-01-01

384

Triassic alkaline magmatism of the Hawasina Nappes: post-breakup melting of the Oman lithospheric mantle  

E-print Network

Triassic alkaline magmatism of the Hawasina Nappes: post-breakup melting of the Oman lithospheric within three tectonostratigraphic groups of the Hawasina Nappes in the Oman Mountains the Oman lithospheric mantle, the original DMM-HIMU signature of which was overprinted during its pervasive

Paris-Sud XI, Université de

385

Drop breakup in the flow through fixed beds via stochastic simulation in model Gaussian fields  

Microsoft Academic Search

Shaqfeh and Koch have shown that the flow through a dilute disordered fixed bed of fibers produces large polymer conformation change beyond a certain critical flow rate [J. Fluid Mech. 244, 17 (1992)]. We now examine the effect of this flow on the shape and breakup of viscous drops. Because the flow through a dilute fixed bed is equivalent to

Alisa B. Mosler; Eric S. G. Shaqfeh

1997-01-01

386

democrite-00023172,version1-3Nov2004 How does breakup influence near-barrier fusion  

E-print Network

channel [4]. The recent avail- ability of light-mass radioactive ion beams such as 6 He [5, 6, 7], 11democrite-00023172,version1-3Nov2004 How does breakup influence near-barrier fusion of weakly bound light nuclei ? C. Beck, N. Rowley, M. Rousseau, F. Haas, P. Bednarczyk, S. Courtin, N. Kintz, F

Paris-Sud XI, Université de

387

Beam Dynamics Simulation Platform and Studies of Beam Breakup in Dielectric Wakefield Structures  

NASA Astrophysics Data System (ADS)

A particle-Green's function beam dynamics code (BBU-3000) to study beam breakup effects is incorporated into a parallel computing framework based on the Boinc software environment, and supports both task farming on a heterogeneous cluster and local grid computing. User access to the platform is through a web browser.

Schoessow, P.; Kanareykin, A.; Jing, C.; Kustov, A.; Altmark, A.; Gai, W.

2010-11-01

388

Beam Dynamics Simulation Platform and Studies of Beam Breakup in Dielectric Wakefield Structures  

Microsoft Academic Search

A particle-Green's function beam dynamics code (BBU-3000) to study beam breakup effects is incorporated into a parallel computing framework based on the Boinc software environment, and supports both task farming on a heterogeneous cluster and local grid computing. User access to the platform is through a web browser.

P. Schoessow; A. Kanareykin; C. Jing; A. Kustov; A. Altmark; W. Gai

2010-01-01

389

Fusion, reaction, and breakup cross sections of {sup 9}Be on a light mass target  

SciTech Connect

The total fusion cross section for the {sup 9}Be+{sup 27}Al system has been measured at energies close and above the Coulomb barrier. Reaction cross sections for this system were derived from elastic scattering data, and the breakup-plus-transfer-channel cross sections were estimated from the difference between these data and measured cross-section fusion.

Marti, G.V.; Capurro, O.A.; Pacheco, A.J.; Testoni, J.E.; Ramirez, M.; Arazi, A. [Laboratorio Tandar, Departamento de Fisica, Comision Nacional de Energia Atomica, Av. del Libertador 8250 (1419), Buenos Aires (Argentina); Gomes, P.R.S.; Padron, I.; Anjos, R.M.; Lubian, J. [Instituto de Fisica, Universidade Federal Fluminense, Av. Litoranea, s/n, Gragota, Niteroi, R.J., 24210-340 (Brazil); Rodriguez, M.D.; Niello, J.O. Fernandez [Laboratorio Tandar, Departamento de Fisica, Comision Nacional de Energia Atomica, Av. del Libertador 8250 (1419), Buenos Aires (Argentina); Escuela de Ciencia y Tecnologia, Universidad de Gral, San Martin (Argentina); Crema, E. [Departamento de Fisica Nuclear, Universidade de Sao Paulo, Caixa Postal 66318, 05315-970, Sao Paulo, S.P. (Brazil)

2005-02-01

390

ICESat profiles of tabular iceberg margins and iceberg breakup at low Ted Scambos,1  

E-print Network

ICESat profiles of tabular iceberg margins and iceberg breakup at low latitudes Ted Scambos,1 Olga of tabular iceberg margins and the Ronne Ice Shelf edge reveal shapes indicative of two types of bending forces. Icebergs and shelf fronts in sea-ice-covered areas have broad ($1000 m wide), rounded, $0.6 m

Boyce, C. Kevin

391

Catastrophic ice shelf breakup as the source of Heinrich event icebergs  

E-print Network

Catastrophic ice shelf breakup as the source of Heinrich event icebergs Christina L. Hulbe,1 of the glacial North Atlantic record abrupt widespread iceberg rafting of detrital carbonate and other lithic (climate) forcings have been proposed. Here we suggest an explanation for the iceberg release

Boyce, C. Kevin

392

Effect of interior surface finish on the break-up of commercial shaped charge liners  

SciTech Connect

A series of experiments aimed at understanding the influence of the liner interior surface finish on the break-up of shaped charge jets has been completed. The experiments used a standard 81-mm shaped charge design, loaded with LX-14 high explosive; incorporating high-precision copper shaped charged liners. The results indicate that a significant reduction of jet break-up time occurs between a surface finish of 99.30 microinches and 375.65 microinches. Surface finishes of 4.78, 44.54 and 99.30 microinches produced significantly better ductility and associated break-up times than the 375.65-microinch finish. The baseline production process high-precision liners were measured to have an average surface finish of 44.54 microinches. The results show that for the shaped charge warhead geometry and explosive combination investigated, some care must be taken in respect to surface finish, but that very fine surface finishes do not significantly improve the jet ductility and associated break-up times.

Baker, E L; Schwartz, A J

1999-08-11

393

PHYSICS OF FLUIDS 25, 072102 (2013) Simulations of the breakup of liquid filaments on a partially  

E-print Network

the contact line shifts accordingly. These waves modulate the mean curvature of the liquid surface of infinite liquid filaments via growing capillary waves and that of finite liquid filaments with dropsPHYSICS OF FLUIDS 25, 072102 (2013) Simulations of the breakup of liquid filaments on a partially

Feng, James J.

394

Breakup of a liquid drop suddenly exposed to a high-speed airstream  

Microsoft Academic Search

The breakup of viscous and viscoelastic drops in the high speed airstream behind a shock wave in a shock tube was photographed with a rotating drum camera giving one photograph every 5 ?s. From these photographs we created movies of the fragmentation history of viscous drops of widely varying viscosity, and viscoelastic drops, at very high Weber and Reynolds numbers.

Daniel D. Joseph; J. Belanger; G. S. Beavers

1999-01-01

395

Marriage Break-Up Rates Similar for Gay, Straight Couples: Study  

MedlinePLUS

... enable JavaScript. Marriage Break-Up Rates Similar for Gay, Straight Couples: Study Research tracked U.S. national data ... Monday, October 6, 2014 Related MedlinePlus Pages Divorce Gay, Lesbian, Bisexual and Transgender Health MONDAY, Oct. 6, ...

396

Post-breakup basaltic magmatism along the East Greenland Tertiary rifted margin  

Microsoft Academic Search

Mafic and ultramafic intrusions in East Greenland adjacent to the offshore Greenland–Iceland ridge were emplaced 5–9 My after continental breakup at 55 Ma [1]. Rare earth element (REE) concentrations determined by secondary ion mass spectrometry are reported for cumulus clinopyroxene from these intrusions, and the data are used to estimate REE abundance in equilibrium melts using available partitioning data. Estimated

Stefan Bernstein; Peter B. Kelemen; Christian Tegner; Mark D Kurz; Jurek Blusztajn; C. Kent Brooks

1998-01-01

397

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

Microsoft Academic Search

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

Chee-Loon Ng

2006-01-01

398

Breakup of bubbles and drops in steadily sheared foams and concentrated emulsions.  

PubMed

This experimental study is focused on the process of bubble breakup in steadily sheared foams, at constant shear rate or constant shear stress. Two different types of surfactants were used and glycerol was added to the aqueous phase, to check how the bubble breakup depends on the surface modulus and on bulk viscosity of the foaming solutions. The experiments show that bubble breakup in foams occurs above a well defined critical dimensionless stress, tau[over]CR identical with(tauCRR/sigma) approximately 0.40, which is independent of surfactant used, solution viscosity, and bubble volume fraction (varied between 92 and 98%). Here tauCR is the dimensional shear stress, above which a bubble with radius R and surface tension sigma would break in sheared foam. The value of the critical stress experimentally found by us tau[over]CR approximately 0.40, is about two orders of magnitude lower than the critical stress for breakup of single bubbles in sheared Newtonian liquids, tau[over]CR approximately 25. This large difference in the critical stress is explained by the strong interaction between neighboring bubbles in densely populated foams, which facilitates bubble subdivision into smaller bubbles. A strong effect of bubble polydispersity on the kinetics of bubble breakup (at similar mean bubble size) was observed and explained. Experiments were also performed with hexadecane-in-water emulsions of drop volume fraction 83%breakup in concentrated emulsions. Qualitatively similar behavior was observed to that of foams, with the critical dimensionless stress for drop breakup being lower, tau[over]CR approximately 0.15, and practically independent of the drop volume fraction and viscosity ratio (varied between 0.01 and 1). This critical stress is by several times lower than the critical stress for breakage of single drops in sheared Newtonian fluids at comparable viscosity ratio, which evidences for facilitated drop subdivision in concentrated emulsions. To explain the measured low values of the critical stress, a different type of capillary instability of the breaking bubbles and drops in concentrated foams and emulsions is proposed and discussed. PMID:19113128

Golemanov, K; Tcholakova, S; Denkov, N D; Ananthapadmanabhan, K P; Lips, A

2008-11-01

399

Transient Droplet Behavior and Droplet Breakup during Bulk and Confined Shear Flow in Blends with One Viscoelastic Component: Experiments, Modelling and Simulations  

SciTech Connect

The transient droplet deformation and droplet orientation after inception of shear, the shape relaxation after cessation of shear and droplet breakup during shear, are microscopically studied, both under bulk and confined conditions. The studied blends contain one viscoelastic Boger fluid phase. A counter rotating setup, based on a Paar Physica MCR300, is used for the droplet visualisation. For bulk shear flow, it is shown that the droplet deformation during startup of shear flow and the shape relaxation after cessation of shear flow are hardly influenced by droplet viscoelasticity, even at moderate to high capillary and Deborah numbers. The effects of droplet viscoelasticity only become visible close to the critical conditions and a novel break-up mechanism is observed. Matrix viscoelasticity has a more pronounced effect, causing overshoots in the deformation and significantly inhibiting relaxation. However, different applied capillary numbers prior to cessation of shear flow, with the Deborah number fixed, still result in a single master curve for shape retraction, as in fully Newtonian systems. The long tail in the droplet relaxation can be qualitatively described with a phenomenological model for droplet deformation, when using a 5-mode Giesekus model for the fluid rheology. It is found that the shear flow history significantly affects the droplet shape evolution and the breakup process in blends with one viscoelastic component. Confining a droplet between two plates accelerates the droplet deformation kinetics, similar to fully Newtonian systems. However, the increased droplet deformation, due to wall effects, causes the steady state to be reached at a later instant in time. Droplet relaxation is less sensitive to confinement, leading to slower relaxation kinetics only for highly confined droplets. For the blend with a viscoelastic droplet, a non-monotonous trend is found for the critical capillary number as a function of the confinement ratio. Finally, experimental data are compared with 3D simulations, performed with a volume-of-fluid algorithm.

Cardinaels, Ruth; Verhulst, Kristof; Moldenaers, Paula [Katholieke Universiteit Leuven, Department of Chemical Engineering, W. de Croylaan 46, B-3001 Leuven (Belgium); Renardy, Yuriko [Polytechnic lnstitute and State University, Department of Mathematics and ICAM, 460 McBryde Hall, Blackburg VA 24061-0123 (United States)

2008-07-07

400

Transient Droplet Behavior and Droplet Breakup during Bulk and Confined Shear Flow in Blends with One Viscoelastic Component: Experiments, Modelling and Simulations  

NASA Astrophysics Data System (ADS)

The transient droplet deformation and droplet orientation after inception of shear, the shape relaxation after cessation of shear and droplet breakup during shear, are microscopically studied, both under bulk and confined conditions. The studied blends contain one viscoelastic Boger fluid phase. A counter rotating setup, based on a Paar Physica MCR300, is used for the droplet visualisation. For bulk shear flow, it is shown that the droplet deformation during startup of shear flow and the shape relaxation after cessation of shear flow are hardly influenced by droplet viscoelasticity, even at moderate to high capillary and Deborah numbers. The effects of droplet viscoelasticity only become visible close to the critical conditions and a novel break-up mechanism is observed. Matrix viscoelasticity has a more pronounced effect, causing overshoots in the deformation and significantly inhibiting relaxation. However, different applied capillary numbers prior to cessation of shear flow, with the Deborah number fixed, still result in a single master curve for shape retraction, as in fully Newtonian systems. The long tail in the droplet relaxation can be qualitatively described with a phenomenological model for droplet deformation, when using a 5-mode Giesekus model for the fluid rheology. It is found that the shear flow history significantly affects the droplet shape evolution and the breakup process in blends with one viscoelastic component. Confining a droplet between two plates accelerates the droplet deformation kinetics, similar to fully Newtonian systems. However, the increased droplet deformation, due to wall effects, causes the steady state to be reached at a later instant in time. Droplet relaxation is less sensitive to confinement, leading to slower relaxation kinetics only for highly confined droplets. For the blend with a viscoelastic droplet, a non-monotonous trend is found for the critical capillary number as a function of the confinement ratio. Finally, experimental data are compared with 3D simulations, performed with a volume-of-fluid algorithm.

Cardinaels, Ruth; Verhulst, Kristof; Renardy, Yuriko; Moldenaers, Paula

2008-07-01

401

Two-nucleon systems in a finite volume. II. S13-D13 coupled channels and the deuteron  

SciTech Connect

The energy spectra of two nucleons in a cubic volume provide access to the two phase shifts and one mixing angle that define the S matrix in the S13-D13 coupled channels containing the deuteron. With the aid of recently derived energy quantization conditions for such systems, and the known scattering parameters, these spectra are predicted for a range of volumes. It is found that extractions of the infinite-volume deuteron binding energy and leading scattering parameters, including the S-D mixing angle at the deuteron pole, are possible from lattice QCD calculations of two-nucleon systems with boosts of |P|?2?/L{radical}3 in volumes with 10??fm?L?14??fm. The viability of extracting the asymptotic D/S ratio of the deuteron wave function from lattice QCD calculations is discussed.

Briceno, Raul [JLAB; Davoudi, Zohreh [Washington U.; Luu, Thomas C. [Forschungszentrum Jülich; Savage, Martin J. [Washington U.

2013-12-01

402

Monitoring ice break-up on the Mackenzie River, Canada, from MODIS Aqua and Terra observations  

NASA Astrophysics Data System (ADS)

Monitoring the response of river ice phenology to variability and changes in high-latitude climate conditions is critical for improving our understanding of northern hydrology and related impacts on geochemical and biological processes. Shorter ice cover duration, thinner ice, and earlier break-up also influence the winter road season, thereby influencing industrial development and the delivery of goods to northern communities. Increased upstream temperatures over the Mackenzie River Basin have caused shorter ice cover seasons, consequently changing the timing and severity of river ice flow in this high-latitude region. This study involves the analysis of Moderate Resolution Imaging Spectroradiometer (MODIS) Level 3 500-m snow products (Aqua and Terra), complemented with 250-m Level 1b data, to monitor ice cover during the break-up period on the Mackenzie River over the 2001-2013 period. Results from the analysis of 10 ice seasons (2003-2012) show that first day ice-off was observed between day of year (DY) 115-125 and ended between DY 145-155, resulting in average melt durations of about 30-40 days. Additional ice-on and ice-off days observed during 2003-2012 resulted from northern flowing entrained river ice that extended the break-up season until DY 155-163. Floating ice flowing northbound could therefore generate multiple periods of ice-cover and ice-free days at the same geographic location. During the ice break-up seasons from 2003-2012, ice melt was initiated by in situ melt over drainage basin (thermodynamic), especially between 61-62o N. However, ice break-up above the 62o N was more dynamically driven. In addition, ice jams were found to be largely controlled by river morphology.

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

2013-12-01

403

Post-breakup Basin Evolution along the South-Atlantic Margins  

NASA Astrophysics Data System (ADS)

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, (c) variations in the type, quantity and distribution of margin sediment, and (d) sea-level changes.

Strozyk, Frank; Back, Stefan; Kukla, Peter

2014-05-01

404

High-fidelity modeling and impact footprint prediction for vehicle breakup analysis  

NASA Astrophysics Data System (ADS)

For decades, vehicle breakup analysis had been performed for space missions that used nuclear heater or power units in order to assess aerospace nuclear safety for potential launch failures leading to inadvertent atmospheric reentry. Such pre-launch risk analysis is imperative to assess possible environmental impacts, obtain launch approval, and for launch contingency planning. In order to accurately perform a vehicle breakup analysis, the analysis tool should include a trajectory propagation algorithm coupled with thermal and structural analyses and influences. Since such a software tool was not available commercially or in the public domain, a basic analysis tool was developed by Dr. Angus McRonald prior to this study. This legacy software consisted of low-fidelity modeling and had the capability to predict vehicle breakup, but did not predict the surface impact point of the nuclear component. Thus the main thrust of this study was to develop and verify the additional dynamics modeling and capabilities for the analysis tool with the objectives to (1) have the capability to predict impact point and footprint, (2) increase the fidelity in the prediction of vehicle breakup, and (3) reduce the effort and time required to complete an analysis. The new functions developed for predicting the impact point and footprint included 3-degrees-of-freedom trajectory propagation, the generation of non-arbitrary entry conditions, sensitivity analysis, and the calculation of impact footprint. The functions to increase the fidelity in the prediction of vehicle breakup included a panel code to calculate the hypersonic aerodynamic coefficients for an arbitrary-shaped body and the modeling of local winds. The function to reduce the effort and time required to complete an analysis included the calculation of node failure criteria. The derivation and development of these new functions are presented in this dissertation, and examples are given to demonstrate the new capabilities and the improvements made, with comparisons between the results obtained from the upgraded analysis tool and the legacy software wherever applicable.

Ling, Lisa

405

Estimating quadrupole couplings of amide deuterons in proteins from direct measurements of 2H spin relaxation rates  

Microsoft Academic Search

The measurements of longitudinal and transverse 2H spin relaxation rates of backbone amide deuterons (DN) in the [U–13C,15N]-labeled protein ubiquitin show that the utility of amide deuterons as probes of backbone order in proteins is compromised by substantial variability of DN quadrupolar coupling constants (QCC) from one amide site to another. However, using the dynamics parameters of 15N–2H bond vectors

Devon Sheppard; Vitali Tugarinov

2010-01-01

406

Attachment Styles and Personal Growth following Romantic Breakups: The Mediating Roles of Distress, Rumination, and Tendency to Rebound  

PubMed Central

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. PMID:24066169

Marshall, Tara C.; Bejanyan, Kathrine; Ferenczi, Nelli

2013-01-01

407

Rift Geometry and Evolution Associated with the Break-up of Pangea  

NASA Astrophysics Data System (ADS)

Diabase dikes related to the rifting of Pangea have been used to elucidate mechanisms by which the super-continent broke-up since the early 1970s. Subsequently, these dikes were related to each other and the massive sills and lava flows that make up the Central Atlantic Magmatic Province (CAMP). Our research focuses on the dikes and mechanisms of continental break-up in the southeastern United States. While, past studies indicate that the majority of Mesozoic diabase dikes within the Carolinas dominantly trend to the northwest, recent work in west-central South Carolina and the Piedmont of North Carolina has revealed numerous previously unmapped dikes with N and NE trends. These dikes have been related to the N and NE trending dikes located in the Northeastern United States via geochemical analyses. Cross-cutting relationships between dikes of different orientation has revealed an apparent pattern whereby the dikes were emplaced in the following order NW, N, and then NE-trending. Recent Ar39/Ar 40 dates suggest that these dikes were all intruded within a 2 million year window, indicating that the least compressive stress field (which would be perpendicular to dike orientation) rotated from NE-SW through E-W to NW-SE within this time period. Based on these observations, which are contrary to previous studies that attribute the northwest trending dikes in the Carolinas to a deep mantle plume, we constructed several finite element models to determine the source of the stress field change. These models were constructed to test the influence of geometry, rifting sequences, and location of force application on the orientation and evolution of stress fields in the Carolinas. Model results suggest that the direction from which rifting progressed has a strong effect on the stress field within the Carolinas and that it is unlikely that rifting began at the Blake Plateau as proposed by the plume hypothesis. Further, it is apparent that the geometry of the rifts themselves has a strong effect on the stress field within the continent, which suggests the need for further mapping of the final rifting events along the southeastern margin of the United States.

Debnam, C.; Beutel, E. K.

2004-12-01

408

Effect of confinement on breakup of planar liquid sheets sandwiched between two gas streams and resulting spray characteristics  

NASA Astrophysics Data System (ADS)

Breakup of a planar liquid sheet in the presence of confining walls has been investigated using nonlinear stability analysis. The gas streams and the liquid sheet sandwiched between them are considered to be moving. Temporal stability analysis has been done for both sinuous and varicose modes of disturbance. The results show the clear influence of the proximity of confining walls on the stability and breakup of liquid sheets, particularly for the varicose mode where satellite drops are predicted for certain ranges of parameters. The presence of wall leads to shorter breakup lengths but larger drop sizes.

Nath, Sujit; Mukhopadhyay, Achintya; Datta, Amitava; Sarkar, Soumalya; Sen, Swarnendu

2014-02-01

409

Resonant formation of {Lambda}(1405) by stopped-K{sup -} absorption in the deuteron  

SciTech Connect

To solve the current debate on the position of the quasibound K{sup -}p state, namely, ''{Lambda}(1405) or {Lambda}*(1420),'' we propose to measure the T{sub 21}=T{sub {Sigma}{pi}<-K}-bar{sub N} {Sigma}{pi} invariant-mass spectrum in stopped-K{sup -} absorption in the deuteron, since the spectrum, reflecting the soft and hard deuteron momentum distribution, is expected to have a narrow quasifree component with an upper edge of M=1430 MeV/c{sup 2}, followed by a significant 'high-momentum' tail toward the lower mass region, where a resonant formation of {Lambda}(1405) of any mass and width in a wide range will be clearly revealed. We introduce a 'deviation' spectrum as defined by DEV = OBS (observed or calculated) / QF (nonresonant quasifree), in which the resonant component can be seen as an isolated peak free from the QF shape.

Esmaili, Jafar [RIKEN, Nishina Center, Wako, Saitama 351-0198 (Japan); Department of Physics, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Akaishi, Yoshinori [RIKEN, Nishina Center, Wako, Saitama 351-0198 (Japan); College of Science and Technology, Nihon University, Funabashi, Chiba 274-8501 (Japan); Yamazaki, Toshimitsu [RIKEN, Nishina Center, Wako, Saitama 351-0198 (Japan); Department of Physics, University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan)

2011-05-15

410

New Precision Measurements of Deuteron Structure Function A(Q) at Low Momentum Transfer  

SciTech Connect

Differences between previous measurements of low momentum transfer electron-deuteron elastic scattering prevent a clean determination of even the sign of the leading low momentum transfer relativistic corrections, or of the convergence of chiral perturbation theory. We have attempted to resolve this issue with a new high-precision measurement in Jefferson Lab Hall A. Elastic electron scattering was measured on targets of tantalum, carbon, hydrogen, and deuterium at beam energy of 685 MeV. The four-momentum transfer covered the range of 0.15 - 0.7 GeV. The experiment included a new beam calorimeter, to better calibrate the low beam currents used in the experiment, and new collimators to better define the spectrometer solid angles. We obtained cross sections of deuteron as ratios to hydrogen cross sections. A fit function of B(Q) world data is newly made and subtracted from cross sections to find values of A(Q).

Byungwuek Lee

2009-08-01

411

Final-state interactions in inclusive deep-inelastic scattering from the deuteron  

We explore the role of final-state interactions (FSI) in inclusive deep-inelastic scattering from the deuteron. Relating the inclusive cross section to the deuteron forward virtual Compton scattering amplitude, a general formula for the FSI contribution is derived in the generalized eikonal approximation, utilizing the diffractive nature of the effective hadron-nucleon interaction. The calculation uses a factorized model with a basis of three resonances with mass W~ 0.6 and Q2 2 increasing in magnitude for lower Q2, but vanishing in the high-Q2 limit due to phase space constraints. The off-shell rescattering contributes at x ~> 0.8 and is taken as an uncertainty on the on-shell result.

Cosyn, Wim [FL Intl U.; Melnitchouk, Wally [JLAB; Sargsian, Misak M. [JLAB

2014-01-01

412

Cross-section studies of important neutron and relativistic deuteron reactions  

NASA Astrophysics Data System (ADS)

The cross-sections of relativistic deuteron reactions on natural copper were studied by the means of activation method. The deuteron beams produced by JINR Nuclotron (Russia) with energies from 1 GeV up to 8 GeV were used. Lack of such cross-sections prevents the usage of copper foils for beam integral monitoring. The copper monitors will help us to improve the beam integral determination during ADS studies. The yttrium samples are very suitable activation detectors for monitoring of neutron fields not only in the ADS studies. But experimental cross-section data for higher energy threshold neutron reactions are still missing. This situation is the reason why we have started to study neutron reactions on yttrium by the means of quasi mono-energetic neutron source based on NPI ?ež cyclotron (Czech Republic).

Wagner, V.; Suchopár, M.; Vrzalová, J.; Chudoba, P.; Herman, T.; Svoboda, O.; Geier, B.; Krása, A.; Majerle, M.; Kugler, A.; Adam, J.; Baldin, A.; Furman, W.; Kadykov, M.; Khushvaktov, J.; Solnyshkin, A.; Tsoupko-Sitnikov, V.; Tyutyunikov, S.; Zavorka, L.; Vladimirova, N.; Bielewicz, M.; Kilim, S.; Szuta, M.; Strugalska-Gola, E.

2014-09-01

413

The deuteron injector progress of the Peking University Neutron Imaging Facility project.  

PubMed

A deuteron radio frequency quadrupoles injector h has been developed at Peking University. A permanent magnetic electron cyclotron resonance (ECR) ion source is used in the injector system. A 50 keV 100 mA proton beam has been extracted from the ECR ion source and the measured normalized rms emittance is 0.11-0.14pi mm mrad. A deuteron beam has also been extracted at 50 kV with 83 mA total current and its emittance is less than 0.18pi mm mrad. The proton beam transmission has been investigated on a low energy beam transport test bench, and up to 93% transmission can be reached. The new injector with two solenoids has been designed and is being constructed. All the development results will be presented in this paper. PMID:20192454

Ren, H T; Peng, S X; Zhang, M; Zhou, Q F; Song, Z Z; Yuan, Z X; Lu, P N; Xu, R; Zhao, J; Yu, J X; Lu, Y R; Guo, Z Y; Chen, J E

2010-02-01

414

Measurement of 230Pa and 186Re Production Cross Sections Induced by Deuterons at Arronax Facility  

NASA Astrophysics Data System (ADS)

A dedicated program has been launched on production of innovative radionuclides for PET imaging and for ?- and ? targeted radiotherapy using proton or ? particles at the ARRONAX cyclotron. Since the accelerator is also able to deliver deuteron beams up to 35 MeV, we have reconsidered the possibility of using them to produce medical isotopes. Two isotopes dedicated to targeted therapy have been considered: 226Th, a decay product of 230Pa, and 186Re. The production cross sections of 230Pa and 186Re, as well as those of the contaminants created during the irradiation, have been determined by the stacked-foil technique using deuteron beams. Experimental values have been quantified using a referenced cross section. The measured cross sections have been used to determine expected production yields and compared with the calculated values obtained using the Talys code with default parameters.

Duchemin, Charlotte; Guertin, Arnaud; Metivier, Vincent; Haddad, Ferid; Michel, Nathalie

2014-02-01

415

Probing the High Momentum Component of the Deuteron at High Q{sup 2}  

SciTech Connect

The {sup 2}H(e,e{sup '}p)n cross section at a momentum transfer of 3.5 (GeV/c){sup 2} was measured over a kinematical range that made it possible to study this reaction for a set of fixed missing momenta as a function of the neutron recoil angle {theta}{sub nq} and to extract missing momentum distributions for fixed values of {theta}{sub nq} up to 0.55 GeV/c. In the region of 35 deg. {<=}{theta}{sub nq}{<=}45 deg. recent calculations, which predict that final-state interactions are small, agree reasonably well with the experimental data. Therefore, these experimental reduced cross sections provide direct access to the high momentum component of the deuteron momentum distribution in exclusive deuteron electrodisintegration.

Boeglin, W. U.; Coman, L.; Ambrozewicz, P.; Kramer, L.; Markowitz, P.; Moteabbed, M.; Nasseripour, R.; Raue, B.; Reinhold, J. [Florida International University, University Park, Florida 33199 (United States); Aniol, K.; Epstein, M.; Margaziotis, D. J. [California State University, Los Angeles, Los Angeles, California 90032 (United States); Arrington, J.; Solvignon, P. [Argonne National Laboratory, Argonne, Illinois 60439 (United States); Batigne, G.; Furget, C.; Kox, S.; Moussiegt, P.; Quemener, G.; Real, J. S. [LPSC, Universite Joseph Fourier, CNRS/IN2P3, INPG, Grenoble (France)

2011-12-23

416

Probing the high momentum component of the deuteron at high Q^2.  

SciTech Connect

The {sup 2}H(e,e'p) cross section at a momentum transfer of 3.5 (GeV/c){sup 2} was measured over a kinematical range that made it possible to study this reaction for a set of fixed missing momenta as a function of the neutron recoil angle {theta}{sub nq} and to extract missing momentum distributions for fixed values of {theta}{sub nq} up to 0.55 GeV/c. In the region of 35{sup o} {le} {theta}{sub nq} {le} 45{sup o} recent calculations, which predict that final state interactions are small, agree reasonably well with the experimental data. Therefore these experimental reduced cross sections provide direct access to the high momentum component of the deuteron momentum distribution in exclusive deuteron electro-disintegration.

Boeglin, Werner; Ambrozewicz, Pawel; Aniol, Konrad; Arrington, John; Batigne, Guillaume; Bosted, Peter; Camsonne, Alexandre; Chang, C; Chen, Jian-Ping; Choi, Seonho; Deur, Alexandre; Epstein, Martin; Finn, John; Frullani, Salvatore; Furget, Christophe; Garibaldi, Franco; Gayou, Olivier; Gilman, Ronald; Hansen, Jens-Ole; Hayes, David; Higinbotham, Douglas; Hinton, Wendy; Hyde, Charles; Ibrahim, Hassan; De Jager, Cornelis; Jiang, Xiaodong; Jones, Mark; Kaufman, Lisa; Klein, Andreas; Kox, Serge; Kramer, Laird; Kumbartzki, Gerfried; Laget, Jean; LeRose, John; Lindgren, Richard; Margaziotiz, Demetrius; Markowitz, Pete; McCormick, Kathy; Meziani, Zein-Eddine; Michaels, Robert; Milbrath, Brian; Mitchell, Joseph; Monaghan, Peter; Moteabbed, Maryam; Moussiegt, Pierre; Nasseripour, Rakhsha; Paschke, Kent; Perdrisat, Charles; Piasetzky, Eliazer; Punjabi, Vina; Qattan, Issam; Quemener, Gilles; Ransome, Ronald; Raue, Brian; Real, Jean-Sebastien; Reinhold, Joerg; Reitz, Bodo; Roche, Rikki; Roedelbronn, Michael; Saha, Arunava; Slifer, Karl; Solvignon-Slifer, Patricia; Sulkosky, Vincent; Ulmer, Paul; Voutier, Eric; Weinstein, Lawrence; Wojtsekhowski, Bogdan

2011-12-01

417

Pionic and Hidden-Color, Six-Quark Contributions to the Deuteron b1 Structure Function  

E-print Network

The b1 structure function is an observable feature of a spin-1 system sensitive to non-nucleonic components of the target nuclear wave function. The contributions of exchanged pions in the deuteron are estimated and found to be of measurable size for small values of x. A simple model for a hidden-color, six-quark configurations (with~ 0.15% probability to exist in the deuteron) is proposed and found to give substantial contributions for values of x>0.2. Good agreement with Hermes data is obtained. Predictions are made for an upcoming JLab experiment. The Close & Kumano sum rule is investigated and found to be a useful guide to understanding various possible effects that may contribute.

Gerald A. Miller

2013-11-18

418

Beta-delayed deuteron emission from (11)Li: decay of the halo.  

PubMed

The deuteron-emission channel in the beta decay of the halo nucleus (11)Li was measured at the Isotope Separator and Accelerator facility at TRIUMF by implanting postaccelerated (11)Li ions into a segmented silicon detector. The events of interest were identified by correlating the decays of (11)Li with those of the daughter nuclei. This method allowed the energy spectrum of the emitted deuterons to be extracted, free from contributions from other channels, and a precise value for the branching ratio B(d)=1.30(13)x10(-4) to be deduced for E(c.m.)>200 keV. The results provide the first unambiguous experimental evidence that the decay takes place essentially in the halo of (11)Li and that it proceeds mainly to the (9)Li+d continuum, opening up a new means to study the halo wave function of (11)Li. PMID:19113404

Raabe, R; Andreyev, A; Borge, M J G; Buchmann, L; Capel, P; Fynbo, H O U; Huyse, M; Kanungo, R; Kirchner, T; Mattoon, C; Morton, A C; Mukha, I; Pearson, J; Ponsaers, J; Ressler, J J; Riisager, K; Ruiz, C; Ruprecht, G; Sarazin, F; Tengblad, O; Van Duppen, P; Walden, P

2008-11-21

419

Molecular Reorientation in Liquids. Deuteron Quadrupole Relaxation in Liquid Deuterium Oxide and Perdeuterobenzene  

Microsoft Academic Search

Temperature-dependence measurements have been made on the deuteron spin—lattice relaxation times for liquid deuterium oxide and perdeuterobenzene. The quadrupole spin—lattice relaxation is expressed in terms of motional models previously developed for magnetic dipole—dipole relaxation. The deuterium oxide data are discussed in terms of microwave, dielectric relaxation, and hydrogen-bonding phenomena. The T1 values follow rather closely a proportionality to absolute temperature

D. E. Woessner

1964-01-01

420

Structure of 152Sm via Deuteron Inelastic Scattering to Probe the Tetrahedral Symmetry  

NASA Astrophysics Data System (ADS)

The structure of 152Sm is investigated in search of the tetrahedral symmetry, which would represent a new quantum effect in the nucleus. The information for the existence of such exotic symmetry may reside in the transition matrix elements of the excited 152Sm nucleus, which are probed through a deuteron inelastic scattering experiment. The tetrahedral band candidates (low-lying negative-parity bands) are observed to be strongly populated, and preliminary coupled-channel calculations have been performed.

Chagnon-Lessard, S.; Garrett, P. E.; Bangay, J. C.; Bianco, L.; Leach, K. G.; Phillips, A. A.; Rand, E. T.; Svensson, C. E.; Ball, G.; Faestermann, T.; Krücken, R.; Hertenberger, R.; Wirth, H. F.; Hertenberger, R.; Wirth, H. F.

2013-03-01

421

The deuteron spin-dependent structure function g 1 d and its first moment  

Microsoft Academic Search

We present a measurement of the deuteron spin-dependent structure function g1d based on the data collected by the COMPASS experiment at CERN during the years 2002–2004. The data provide an accurate evaluation for ?1d, the first moment of g1d(x), and for the matrix element of the singlet axial current, a0. The results of QCD fits in the next to leading

V. Yu. Alexakhin; G. D. Alexeev; M. Alexeev; A. Amoroso; B. Bade?ek; F. Balestra; J. Ball; J. Barth; G. Baum; M. Becker; Y. Bedfer; C. Bernet; R. Bertini; M. Bettinelli; R. Birsa; J. Bisplinghoff; P. Bordalo; F. Bradamante; A. Bressan; G. Brona; E. Burtin; M. P. Bussa; V. N. Bytchkov; A. Chapiro; A. Cicuttin; M. Colantoni; A. A. Colavita; S. Costa; M. L. Crespo; N. d'Hose; S. Dalla Torre; S. S. Dasgupta; R. De Masi; N. Dedek; D. Demchenko; O. Yu. Denisov; L. Dhara; V. Diaz; A. M. Dinkelbach; S. V. Donskov; V. A. Dorofeev; N. Doshita; V. Duic; W. Dünnweber; A. Efremov; P. D. Eversheim; W. Eyrich; M. Faessler; P. Fauland; A. Ferrero; L. Ferrero; M. Finger; H. Fischer; J. Franz; J. M. Friedrich; V. Frolov; R. Garfagnini; F. Gautheron; O. P. Gavrichtchouk; S. Gerassimov; R. Geyer; M. Giorgi; B. Gobbo; S. Goertz; A. M. Gorin; O. A. Grajek; B. Grube; A. Guskov; F. Haas; J. Hannappel; D. von Harrach; T. Hasegawa; S. Hedicke; F. H. Heinsius; R. Hermann; C. Heß; F. Hinterberger; M. von Hodenberg; N. Horikawa; S. Horikawa; I. Horn; C. Ilgner; A. I. Ioukaev; I. Ivanchin; O. Ivanov; T. Iwata; R. Jahn; A. Janata; R. Joosten; N. I. Jouravlev; E. Kabuß; D. Kang; B. Ketzer; G. V. Khaustov; Yu. A. Khokhlov; Yu. Kisselev; F. Klein; K. Klimaszewski; S. Koblitz; J. H. Koivuniemi; V. N. Kolosov; E. V. Komissarov; K. Kondo; K. Königsmann; I. Konorov; V. F. Konstantinov; A. S. Korentchenko; A. Korzenev; A. M. Kotzinian; N. A. Koutchinski; O. Kouznetsov; K. Kowalik; D. Kramer; N. P. Kravchuk; G. V. Krivokhizhin; Z. V. Kroumchtein; J. Kubart; R. Kuhn; V. Kukhtin; F. Kunne; K. Kurek; M. E. Ladygin; M. Lamanna; J. M. Le Goff; A. A. Lednev; J. Lichtenstadt; T. Liska; I. Ludwig; A. Maggiora; M. Maggiora; A. Magnon; G. K. Mallot; C. Marchand; J. Marroncle; A. Martin; J. Marzec; L. Masek; F. Massmann; T. Matsuda; D. Matthiä; A. N. Maximov; W. Meyer; A. Mielech; Yu. V. Mikhailov; M. A. Moinester; T. Nagel; O. Nähle; J. Nassalski; S. Neliba; D. P. Neyret; V. I. Nikolaenko; K. Nikolaev; A. A. Nozdrin; V. F. Obraztsov; A. G. Olshevsky; M. Ostrick; A. Padee; P. Pagano; S. Panebianco; D. Panzieri; S. Paul; D. V. Peshekhonov; V. D. Peshekhonov; G. Piragino; S. Platchkov; J. Pochodzalla; V. A. Polyakov; G. Pontecorvo; A. A. Popov; J. Pretz; S. Procureur; C. Quintans; S. Ramos; G. Reicherz; E. Rondio; A. M. Rozhdestvensky; D. Ryabchikov; V. D. Samoylenko; A. Sandacz; H. Santos; M. G. Sapozhnikov; I. A. Savin; P. Schiavon; C. Schill; L. Schmitt; W. Schroeder; D. Seeharsch; M. Seimetz; D. Setter; O. Yu. Shevchenko; H.-W. Siebert; L. Silva; A. N. Sissakian; M. Slunecka; G. I. Smirnov; F. Sozzi; A. Srnka; F. Stinzing; M. Stolarski; V. P. Sugonyaev; M. Sulc; R. Sulej; V. V. Tchalishev; S. Tessaro; F. Tessarotto; A. Teufel; L. G. Tkatchev; S. Trippel; G. Venugopal; M. Virius; N. V. Vlassov; R. Webb; E. Weise; Q. Weitzel; R. Windmolders; W. Wi?licki; K. Zaremba; M. Zavertyaev; E. Zemlyanichkina; J. Zhao; R. Ziegler; A. Zvyagin

2007-01-01

422

Dissecting deuteron Compton scattering I: The observables with polarised initial states  

NASA Astrophysics Data System (ADS)

A complete set of linearly independent observables in Compton scattering with arbitrarily polarised real photons off an arbitrarily polarised spin-1 target is introduced, for the case that the final-state polarisations are not measured. Adopted from the one widely used, e.g., in deuteron photo-dissociation, it consists of 18 terms: the unpolarised cross section, the beam asymmetry, 4 target asymmetries and 12 asymmetries in which both beam and target are polarised. They are expressed by the helicity amplitudes and —where available— related to observables discussed by other authors. As application to deuteron Compton scattering, their dependence on the (isoscalar) scalar and spin dipole polarisabilities of the nucleon is explored in Chiral Effective Field Theory with dynamical ?(1232) degrees of freedom at order e 2 ? 3. Some asymmetries are sensitive to only one or two dipole polarisabilities, making them particularly attractive for experimental studies. At a photon energy of 100 MeV, a set of 5 observables is identified from which one may be able to extract the spin polarisabilities of the nucleon. These are experimentally realistic but challenging and mostly involve tensor-polarised deuterons. Relative to Compton scattering from a nucleon, sensitivity to the "mixed" spin polarisabilities ? E1 M2 and ? M1 E2 is increased because of the interference with the D wave component of the deuteron and with its pion-exchange current. An interactive Mathematica 9.0 notebook with results for all observables at photon energies up to 120 MeV is available from hgrie@gwu.edu.

Grießhammer, Harald W.

2013-08-01

423

Low-beam-loss design of a compact, high-current deuteron radio frequency quadrupole accelerator  

Microsoft Academic Search

A 201.5MHz, 50mA, 2.0MeV deuteron radio frequency quadrupole accelerator is proposed as the neutron generator for the neutron experiment facility project at Peking University, China. Based on better understanding of beam losses, some new optimization procedures concerning both longitudinal and transverse dynamics are adopted. Accordingly, the beam transmission efficiency is improved from 91.2% to 98.3% and the electrode length is

C. Zhang; Z. Y. Guo; A. Schempp; R. A. Jameson; J. E. Chen; J. X. Fang

2004-01-01

424

On the solar neutrino problem in the relativistic field theory model of the deuteron  

E-print Network

The relativistic field theory model of the deuteron suggested by us previously is applied to the calculation of the reaction rate of the low-energy two-proton fusion p + p -> D + e+ + nu. The theoretical prediction of the reaction rate obtained is 2.9 times larger than given by the potential approach. This leads to a strong suppression of the high energy solar neutrino fluxes.

H. Oberhummer; A. N. Ivanov; N. I. Troitskaya; M. Faber

1997-05-16

425

The development of high resolution coordinate detectors for the DEUTERON facility  

NASA Astrophysics Data System (ADS)

The DEUTERON internal target facility at the VEPP-3 storage ring at BINP is intended for the experiments on interaction of electrons and positrons with proton and deuteron. These experiments require high resolution tracking detectors which can provide the energy and angles of scattered electron. The prototype detector with a sensitive area of 160 × 40 mm2 was built and proved to be operational. It consists of three cascades of gaseous electron multiplier (GEM), the readout structure and detector electronics. Readout structure has 640 strips which are uniformly distributed in two layers skewed by 30 degrees. Electronics of the detector includes APC128 ASICs, Altera Cyclone III FPGA, 100 MBit ethernet. In the APC128 ASIC each channel has a separate analog pipeline consisting of 32 cells which are cyclically switched by a global clock synchronized to the bunch crossing rate ( ~ 4 MHz). For the needs of DEUTERON facility the expected resolution of less than 100 ?m and thickness of ~ 0.15% of radiation length are considered to be quite satisfactory. The latest results obtained at the test beam facility at the VEPP-4M collider show that detector is fully operational with maximum detection efficiency reached 98%.

Kudryavtsev, V. N.; Shekhtman, L. I.; Bobrovnikov, V. S.; Maltsev, T. V.; Nikolenko, D. N.; Rachek, I. A.

2014-09-01

426

Neutron-Deuteron Elastic Scattering at 100-300 MeV  

NASA Astrophysics Data System (ADS)

The differential cross section for neutron-deuteron elastic scattering was measured at six angles over the center-of-mass angular range 65^circ - 130^circ and incident neutron energies 100-300 MeV at the LANSCE/WNR facility of the Los Alamos National Laboratory. Witala et al.(H. Witala et al.), Phys. Rev. Lett. 81, 1183 (1998) have suggested that the differential cross section for nucleon-deuteron scattering at large angles may be sensitive to the presence of a three-nucleon force. In the present experiment, a liquid deuterium target was exposed to the pulsed neutron beam, with incident neutron energy determined by time of flight. The scattered neutrons, detected by a horizontal array of plastic scintillator bars, and the recoil deuterons, detected by ? E-E (plastic scintillator -- CsI) telescopes, were observed in coincidence. The resulting angular distributions for several incident neutron energies are compared with theoretical predictions and previous measurements in both nd and pd systems.

Chtangeev, M.; Akdogan, T.; Franklin, W. A.; Matthews, J. L.; Safkan, Y.; Wender, S. A.; Kovash, M.; Ojha, M.; Brady, P.; De Young, R.; Kroening, D.; Tuminaro, S.; Yuly, M.

2002-04-01

427

Deuteron beam interaction with Li jet for a neutron source test facility  

SciTech Connect

Testing and evaluating candidate fusion reactor materials in a high-flux, high-energy neutron environment are critical to the success and economic feasibility of a fusion device. The current understanding of materials behavior in fission-like environments and existing fusion facilities is insufficient to ensure the necessary performance of future fusion reactor components. An accelerator-based deuterium-lithium system to generate the required high neutron flux for material testing is considered to be the most promising approach in the near future. In this system, a high-energy (30-40 MeV) deuteron beam impinges on a high-speed (10-20 m/s) lithium jet to produce the high-energy (>14 MeV) neutrons required to simulate a fusion environment via the Li (d,n) nuclear stripping reaction. Interaction of the high-energy deuteron beam and the subsequent response of the high-speed lithium jet are evaluated in detail. Deposition of the deuteron beam, jet-thermal hydraulic response, lithium-surface vaporization rate, and dynamic stability of the jet are modeled. It is found that lower beam kinetic energies produce higher surface temperature and consequently higher Li vaporization rates. Larger beam sizes significantly reduce both bulk and surface temperatures. Thermal expansion and dynamic velocities (normal to jet direction) due to beam energy deposition and momentum transfer are much lower than jet flow velocity and decrease substantially at lower beam current densities.

Hassanein, A.

1995-09-01

428

Measurement of the Electric and Magnetic Elastic Structure Functions of the Deuteron at Large Momentum Transfers  

SciTech Connect

The deuteron elastic structure functions, A(Q{sup 2}) and B(Q{sup 2}), have been extracted from cross section measurements of elastic electron-deuteron scattering in coincidence using the Continuous Electron Beam Accelerator and Hall A Facilities of Jefferson Laboratory. Incident electrons were scattered off a high-power cryogenic deuterium target. Scattered electrons and recoil deuterons were detected in the two High Resolution Spectrometers of Hall A. A(Q{sup 2}) was extracted from forward angle cross section measurements in the squared four-momentum transfer range 0.684 ? Q{sup 2} ? 5.90 (GeV/c){sup 2}. B(Q{sup 2}) was determined by means of a Rosenbluth separation in the range 0.684 ? Q{sup 2} ? 1.325 (GeV/c){sup 2}. The data are compared to theoretical models based on the impulse approximation with the inclusion of meson-exchange currents and to predictions of quark dimensional scaling and perturbative quantum chromodynamics. The results are expected to provide insights into the transition from meson-nucleon to quark-gluon descriptions of the nuclear two-body system.

Riad Suleiman

1999-10-01

429

Final-state interactions in deep-inelastic scattering from a tensor polarized deuteron target  

NASA Astrophysics Data System (ADS)

Deep-inelastic scattering (DIS) from a tensor polarized deuteron is sensitive to possible non-nucleonic components of the deuteron wave function. To accurately estimate the size of the nucleonic contribution, final-state interactions (FSIs) need to be accounted for in calculations. We outline a model that, based on the diffractive nature of the effective hadron-nucleon interaction, uses the generalized eikonal approximation to model the FSIs in the resonance region, taking into account the proton-neutron component of the deuteron. The calculation uses a factorized model with a basis of three resonances with mass W < 2 GeV as the relevant set of effective hadron states entering the final-state interaction amplitude for inclusive DIS. We present results for the tensor asymmetry observable Azz for kinematics accessible in experiments at Jefferson Lab and Hermes. For inclusive DIS, sizeable effects are found when including FSIs for Bjorken x > 0.2, but the overall size of Azz remains small. For tagged spectator DIS, FSIs effects are largest at spectator momenta around 300 MeV and for forward spectator angles.

Cosyn, W.; Sargsian, M.

2014-10-01

430

Calculations of Proton Emission Cross Sections in Deuteron Induced Reactions of Some Fusion Structural Materials  

NASA Astrophysics Data System (ADS)

The growing demands for energy consumption have led to the increase of the research and development activities on new energy sources. Fusion energy has the highest potential to become a very safe, clean and abundant energy source for the future. To get energy from fusion are needed for development of fusion reactor technology. Particularly, the design and development of international facilities as International Thermonuclear Experimental Reactor and International Fusion Material Irradiation Facility requires for the cross-section data of deuteron induced reactions. Moreover, the selection of fusion structural materials are an indispensable component for this technology. Therefore, the cross-section data of deuteron induced reactions on fusion structural materials are of great importance for development of fusion reactor technology. In this study, reaction model calculations of the cross sections of deuteron induced reactions on structural fusion materials such as 27Al, 59Co, 55Mn, 50Cr, 54Cr, 64Ni, 109Ag, 184W and 186W have been carried out for incident energies up to 50 MeV. In these calculations, the pre-equilibrium and equilibrium effects for ( d, p) stripping reactions have been investigated. The pre-equilibrium calculations involve the new evaluated the geometry dependent hybrid model and hybrid model. Equilibrium effects are calculated according to the Weisskopf-Ewing model. In the calculations the program code ALICE/ASH was used. The calculated results are discussed and compared with the experimental data taken from the literature.

Yi?it, M.; Tel, E.; Tan?r, G.

2013-06-01

431

Nuclear fusion of deuterons with light nuclei driven by Coulomb explosion of nanodroplets  

NASA Astrophysics Data System (ADS)

Theoretical-computational studies of table-top laser-driven nuclear fusion of high energy (up to 15 MeV) deuterons with 7Li, 6Li, T, and D demonstrate the attainment of high fusion yields. The reaction design constitutes a source of Coulomb exploding deuterium nanodroplets driven by an ultraintense, near-infrared, femtosecond Gaussian laser pulse (peak intensity 2 × 1018-5 × 1019 W cm-2) and a solid, hollow cylindrical target containing the second reagent. The exploding nanodroplets source is characterized by the deuteron kinetic energies, their number, and the laser energy absorbed by a nanodroplet. These were computed by scaled electron and ion dynamics simulations, which account for intra-nanodroplet laser intensity attenuation and relativistic effects. The fusion yields Y are determined by the number of the source deuterons and by the reaction probability. When laser intensity attenuation is weak within a single nanodroplet and throughout the nanodroplets assembly, Y exhibits a power law increase with increasing the nanodroplet size. Y is maximized for the nanodroplet size and laser intensity corresponding to the "transition" between the weak and the strong intensity attenuation domains. The dependence of Y on the laser pulse energy W scales as W2 for weak assembly intensity attenuation, and as W for strong assembly intensity attenuation. This reaction design attains the highest table-top fusion efficiencies (up to 4 × 109 J-1 per laser pulse) obtained up to date.

Ron, Shlomo; Last, Isidore; Jortner, Joshua

2012-11-01

432

ESTIMATE OF THE DEPTH OF ICE COVER OF BAIKAL LAKE ON THE BASIS OF SPECTRA OF NOISE OF ICE BREAKUPS  

Microsoft Academic Search

In the report, we present the results of the spectral processing of acoustic noise, generated during breakups of ice cover of Baikal Lake. Frequencies associated with the mean depth of ice cover are identifies. The \\

V. P. Mamyshev; S. L. Odintsov; SB RAS

2008-01-01

433

Nuclear Structure of {sup 12}C from Break-up Studies in Complete Kinematics  

SciTech Connect

A complete kinematics study of the {sup 10}B({sup 3}He,palphaalphaalpha) and {sup 11}B({sup 3}He,dalphaalphaalpha) reactions has been performed to study the multi-particle break-up of {sup 12}C resonances above the triple-alpha threshold. Four-particle coincidence detection gives us complete information on the direction and energy of the individual alpha particles from the decay of {sup 12}C, allowing us to extract new information on the structure of {sup 12}C which we shall present in this contribution. We have observed gamma de-excitation of the T = 1 15.11 MeV resonance using charged particle detectors, and have constructed Dalitz plots of the individual resonances in {sup 12}C using the complete kinematics information of the alpha particles which come from their break-up.

Alcorta, M.; Borge, M. J. G.; Cubero, M.; Dominguez-Reyes, R.; Fraile, L.; Galaviz, D.; Madurga, M.; Maira, A.; Obradors, D.; Perea, A.; Tengblad, O.; Turrion, M. [Instituto de Estructura de la Materia, CSIC, Serrano 113 bis, Madrid E-28006 (Spain); Fulton, B.; Fynbo, H. O. U.; Hyldegaard, S.; Jeppesen, H.; Kirsebom, O.; Riisager, K. [Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus C (Denmark); Jonson, B.; Nilsson, T. [Fundamental Physics, Chalmers Univ. of Technology, S-41296 Goeteborg (Sweden)

2009-08-26

434

Timing of hot spot--related volcanism and the breakup of madagascar and India.  

PubMed

Widespread basalts and rhyolites were erupted in Madagascar during the Late Cretaceous. These are considered to be related to the Marion hot spot and the breakup of Madagascar and Greater India. Seventeen argon-40/argon-39 age determinations reveal that volcanic rocks and dikes from the 1500-kilometer-long rifted eastern margin of Madagascar were emplaced rapidly (mean age = 87.6 +/- 0.6 million years ago) and that the entire duration of Cretaceous volcanism on the island was no more than 6 million years. The evidence suggests that the thick lava pile at Volcan de l'Androy in the south of the island marks the focal point of the Marion hot spot at approximately 88 million years ago and that this mantle plume was instrumental in causing continental breakup. PMID:17813912

Storey, M; Mahoney, J J; Saunders, A D; Duncan, R A; Kelley, S P; Coffin, M F

1995-02-10

435

Analysis of Coulomb breakup experiments of 8B with a dynamical eikonal approximation  

E-print Network

Various measurements of the Coulomb breakup of 8B are analyzed within the dynamical eikonal approximation using a single description of 8B. We obtain a good agreement with experiment for different observables measured between 40 and 80 MeV per nucleon. A simple 7Be-p potential model description of 8B seems sufficient to describe all observables. In particular, the asymmetry in parallel-momentum distributions due to E1-E2 interferences is well reproduced without any scaling. The projectile-target nuclear interactions seem negligible if data are selected at forward angles. On the contrary, like in previous analyzes we observe a significant influence of higher-order effects. The accuracy of astrophysical S factors for the 7Be(p,gamma)8B reaction at stellar energies extracted from breakup measurements therefore seems difficult to evaluate.

Goldstein, G; Baye, D

2007-01-01