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1

Breakup of deuterons on tritons  

NASA Astrophysics Data System (ADS)

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 4H* and 4He* 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 4H* 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.; 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.

2012-12-01

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

Deuteron-proton breakup at medium energies  

NASA Astrophysics Data System (ADS)

Recently, the database for the breakup of a deuteron in collision with a proton has been significantly enriched in the domain of medium energies. High precision experimental data for the cross section, vector (proton)-analyzing power and vector- and tensor (deuteron)-analyzing powers were collected with detection systems covering a large part of the phase space of the 1H(vec d, pp)n and 2H(vec p, pp)n reactions. A series of experiments were carried out with deuteron beams with energies of 100, 130 and 160 MeV and proton beams with energies of 135 and 190 MeV, each of them providing a few hundred data points per observable, obtained on systematic grids of kinematical variables within the studied angular ranges. Usage of the multidetector systems with significant solid angle coverage provides not only very rich data sets but also a good opportunity for controlling the consistency of the results. The ways of exploiting all these advantages in high precision measurements are discussed. The experimental results are compared with the theoretical predictions, in which the full dynamics of the three-nucleon (3N) system is obtained in different ways: realistic nucleon-nucleon (NN) potentials are combined with model 3N forces (3NF) or with an effective 3N interaction resulting from the explicit treatment of the ?-isobar excitation. On top of the NN and 3N nuclear forces Coulomb interaction can be also included into the calculational framework. Relativistic calculations can be performed with realistic NN potentials alone. 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, while at the next order without taking into account the corresponding 3NF contributions. Comparing the calculated observables with the experimental data shows the sensitivity of the cross sections to 3NFs and to Coulomb force effects, while there is no sensitivity of the deuteron vector analyzing powers to any additional dynamics beyond the NN forces. The behavior of the tensor analyzing powers and of the proton analyzing powers at higher energy is rather complicated, showing discrepancies between the calculations and the experimental data which must be considered as indications of deficiencies in the spin part of the assumed models of the 3N system dynamics. The richness of the database calls for a systematic survey of the results, therefore kinematical coordinates convenient for that purpose and certain methods of comparison to the theoretical calculations are discussed, together with signposts to future developments in the field of 3N system studies.

Kistryn, St.; Stephan, E.

2013-06-01

4

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

5

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

6

Hard breakup of the deuteron into two {Delta} isobars  

SciTech Connect

We study high-energy photodisintegration of the deuteron into two {Delta} 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{yields}{Delta}{Delta} 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{yields}{Delta}{Delta} scattering. We predict that the cross section of the deuteron breakup to {Delta}{sup ++}{Delta}{sup -} is 4-5 times larger than that of the breakup to the {Delta}{sup +}{Delta}{sup 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 {Delta} isobars are the result of the disintegration of the preexisting {Delta}{Delta} components of the deuteron wave function. In this case, one expects the angular distributions and cross sections of the breakup in both {Delta}{sup ++}{Delta}{sup -} and {Delta}{sup +}{Delta}{sup 0} channels to be similar.

Granados, Carlos G.; Sargsian, Misak M. [Florida International University, Miami, Florida 33199 (United States)

2011-05-15

7

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

8

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.

2014-01-01

9

Quark-exchange effects in a deuteron breakup at intermediate energy.  

National Technical Information Service (NTIS)

Microscopical approach to a deuteron breakup at high and intermediate energies is proposed. We show that the quark exchange effects, resulting from the full asymmetry of the 6q-deuteron wave function with respect to the pair permutations of quark variable...

A. P. Kobushkin A. I. Syamtomov L. Glozman

1995-01-01

10

Vector and tensor analyzing powers in deuteron-proton breakup  

NASA Astrophysics Data System (ADS)

Vector and tensor analyzing powers of the breakup reaction at 130 and 100 MeV deuteron beam energies have been measured at KVI Groningen with the use of the detection systems covering large fractions of the phase space. The high precision data are compared to the theoretical predictions based on various approaches to describe the three nucleon (3N) system dynamics. Theoretical predictions describe very well the vector analyzing power data, with no need to include any three-nucleon force effects for these observables. The tensor analyzing powers can be also very well reproduced by calculations in most of the studied region, but locally certain discrepancies are observed. At 130 MeV for Axy such discrepancies usually appear, or are enhanced, when model 3N forces (3NFs), TM99 or Urbana IX, are included. Problems of all theoretical approaches with describing Axx and Ayy are limited to very small regions of the phase space, usually characterized with the lowest relative energies of the two protons. Predicted effects of 3NFs are much lower at 100 MeV, therefore at this energy equally good consistency between the data and the calculations is obtained with or without 3NFs.

Stephan, E.; Kistryn, St.; Kalantar-Nayestanaki, N.

2011-05-01

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

Scattering length measurements from radiative pion capture and neutron-deuteron breakup  

SciTech Connect

The neutron-neutron and neutron-proton {sup 1}S{sub 0} scattering lengths a{sub nn} and a{sub np}, respectively, were determined simultaneously from the neutron-deuteron breakup reaction. Their comparison with the recommended values obtained from two body reactions gives a measure of the importance of three-nucleon force effects in the three-nucleon continuum. In order to check on the result obtained for a{sub nn} from the two-body {pi}{sup {minus}}-d capture reaction, a new measurement was performed at LANL. Preliminary results of the three experiments are given.

Gibson, B.F. [Los Alamos National Lab., NM (United States); Tornow, W. [Duke Univ., Durham, NC (United States). Dept. of Physics]|[Triangle Universities Nuclear Lab., Durham, NC (United States); Carman, T.S. [Lawrence Livermore National Lab., CA (United States)] [and others

1997-07-01

13

Cross-section measurements of neutron-deuteron breakup at 13.0 MeV  

SciTech Connect

Cross-section measurements of seven exit-channel configurations in the neutron-deuteron breakup at 13.0 MeV are reported and compared to rigorous calculations. Our data are consistent with those of previous measurements in four of six configurations. The present data for five configurations are in good agreement with theoretical predictions. The cross-section data for the space-star and another out-of-plane configuration are larger than the theoretical predictions by more than three standard deviations. The previously observed 20% discrepancy between theory and data for the space-star configuration is confirmed in the present work. The inclusion of the Tucson-Melbourne 2{pi}-exchange three-nucleon force changes the predicted cross section by only 2% and in the wrong direction needed to bring theory into agreement with data.

Setze, H.R.; Howell, C.R.; Tornow, W.; Braun, R.T.; Gonzalez Trotter, D.E.; Hussein, A.H.; Pedroni, R.S.; Roper, C.D.; Salinas, F.; Slaus, I.; Vlahovic, B.; Walter, R.L.; Mertens, G.; Lambert, J.M.; Witala, H.; Gloeckle, W. [Duke University and Triangle Universities Nuclear Laboratory, Durham, North Carolina 27708 (United States); Institute of Physics, University of Tuebingen, D-72074 Tuebingen (Germany); Department of Physics, Georgetown University, Washington, District of Columbia 20057 (United States); Institute of Physics, Jagellonian University, Reymonta 4, PL-30059 Cracow (Poland); Institut fuer Theoretishe Physik II, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)

2005-03-01

14

Increase in |SL| induced by channel coupling: The case of deuteron breakup  

NASA Astrophysics Data System (ADS)

For deuteron scattering from 58Ni at laboratory energies of 56, 79, and 120 MeV, we study the dynamic polarization potentials (DPPs) induced by S-wave and D-wave breakup (BU), separately and together, in order to gain insight into the nature of the DPP as well as a counterintuitive property: the existence of L values for which the BU coupling increases |SL|, a ‘wrong-way’ effect. The effect is associated with the existence of emissive regions in the imaginary DPP, suggesting a connection with the nonlocal nature of the DPP. The same relationship was previously found for 6Li scattering, indicating a generic effect bearing on the dynamics of nuclear reactions.

Mackintosh, R. S.; Pang, D. Y.

2012-10-01

15

Faddeev calculation for breakup neutron-deuteron scattering at 14.1 MeV lab energy  

NASA Astrophysics Data System (ADS)

A new computational method for solving nucleon-deuteron breakup scattering problem has been applied to study inelastic neutron-deuteron scattering in the framework of configuration-space Faddeev-Noyes-Noble-Merkuriev equations. This method is based on the spline-decomposition in angular variable and on a generalization of the Numerov method for hyperradius. The Merkuriev-Gignoux-Laverne approach has been generalized for arbitrary nucleon-nucleon potentials and arbitrary number of partial waves. Neutron-deuteron observables at the incident nucleon energy 14.1 MeV have been calculated using the charge-independent Argonne AV14 nucleon-nucleon potential. Results have been compared with those of other authors and with experimental nucleon-deuteron scattering data.

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

2013-04-01

16

New data on {ital T}{sub 20} in inclusive deuteron breakup at 9 GeV/c on protons and correlation between polarization observables  

SciTech Connect

Experiments probing the deuteron structure at short distances with smooth transition to the intermediate and large distances provide a basis for crucial tests of the modern QCD-motivated theory of strong interactions. Such data are particularly important when the internal momentum is too large to allow separate identities for the nucleons in the deuteron. The very notion of the wave function is not defined in this region at all. Progress has been achieved{sup 1,2} especially in the measurement of cross section data and polarization observables for the inclusive deuteron breakup {ital A}({ital d},{ital p}){ital X} for beam momenta up to 9 {ital GeV}/{ital c} (Fig. 1). The main results are as follows: (1) the empirical momentum density (EMD) of the nucleon in the deuteron is almost independent of the deuteron energy, of the target and of the type of the inclusive breakup reaction (see Fig. 1b and refs.{sup 1,2}). (2) Polarization observables are also largely independent of the target and initial energy up to 9 {ital GeV}/{ital c}, as follows from comparison of our new data with data of ref.{sup 2} (Fig. 1a,c,d). (3) Impulse Approximation (IA) predictions are in agreement with all data sets only for {ital k}{le}150 {ital MeV}/{ital c}; a drastic disagreement is seen beyond this region. More complicated models, taking into account various additional contributions to the reaction mechanism, or ``relativization effects,`` result in a partial success for a given observable, but not for the whole set of observables (Fig. 1,2 and ref.{sup 3}; see also references therein). {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

Azhgirey, L.S.; Afanasyev, S.V.; Chernykh, E.V. [JINR, 141980, Dubna, Moscow Region (Russian Federation); Kobushkin, A.P. [JINR, 141980, Dubna, Moscow Region (Russian Federation)]|[ITP, 252130, Metrologicheskaya 14, Kiev (Ukraine); Ladygin, V.P.; Nedev, S. [JINR, 141980, Dubna, Moscow Region (Russian Federation); Penchev, L. [JINR, 141980, Dubna, Moscow Region (Russian Federation)]|[INRNP, 1184, bul. Lenin 72, Sofia (Bulgaria); Perdrisat, C.F. [JINR, 141980, Dubna, Moscow Region (Russian Federation)]|[The College of William and Mary, Williamsburg, Virginia 23185 (United States); Piskunov, N.M. [JINR, 141980, Dubna, Moscow Region (Russian Federation); Punjabi, V. [JINR, 141980, Dubna, Moscow Region (Russian Federation)]|[Norfolk State University, Norfolk, Virginia 23504 (United States); Sitnik, I.M.; Stoletov, G.D.; Strokovsky, E.A. [JINR, 141980, Dubna, Moscow Region (Russian Federation); Syamtomov, A.I. [JINR, 141980, Dubna, Moscow Region (Russian Federation)]|[ITP, 252130, Metrologicheskaya 14, Kiev (Ukraine); Zaporozhets, S.A. [JINR, 141980, Dubna, Moscow Region (Russian Federation)

1995-05-10

17

Deuteron breakup pd?{pp}sn with forward emission of a fast 1S0 diproton  

NASA Astrophysics Data System (ADS)

The deuteron breakup reaction pd?{pp}sn, where {pp}s is a fast proton pair emitted in forward direction with small excitation energy Epp<3 MeV, has been studied at proton beam energies of 0.5-2.0 GeV using the ANKE spectrometer at COSY-Jülich. The differential c.m. cross sections are measured in complete kinematics and provide angular distributions of the neutron emission angle in the range ?n=168°-180°, the dependence on beam energy at ?n=180°, angular distributions of the direction of the proton in the pp rest frame, and distributions of the excitation energy Epp of the proton pair. The obtained data are analyzed on the basis of theoretical models previously developed for the pd?dp process in a similar kinematics and properly modified for the diproton channel in pd?{pp}sn. It is shown that the measured observables are highly sensitive to the short-range part of the nucleon-nucleon interaction.

Dymov, S.; Komarov, V.; Macharashvili, G.; Uzikov, Yu.; Azarian, T.; Imambekov, O.; Kulikov, A.; Kurbatov, V.; Merzliakov, S.; Zalikhanov, B.; Zhuravlev, N.; Büscher, M.; Hartmann, M.; Hejny, V.; Kacharava, A.; Nekipelov, M.; Ohm, H.; Rathmann, F.; Seyfarth, H.; Stein, H. J.; Ströher, H.; Khoukaz, A.; Mersmann, T.; Rausmann, T.; Barsov, S.; Mikirtychiants, S.; Kämpfer, B.; Kulessa, P.; Nioradze, M.; Trusov, S.; Yaschenko, S.

2010-04-01

18

Measurement of the Reaction {sup 2}H(e,e{sup '}) at 180 deg. Close to the Deuteron Breakup Threshold  

SciTech Connect

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

Ryezayeva, N.; Burda, O.; Byelikov, A.; Chernykh, M.; Enders, J.; Kalmykov, Y.; Neumann-Cosel, P. von; Poltoratska, I.; Pysmenetska, I.; Rathi, S.; Richter, A.; Schrieder, G.; Shevchenko, A.; Yevetska, O. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, D-64289 Darmstadt (Germany); Arenhoevel, H. [Institut fuer Kernphysik, Universitaet Mainz, D-55099 Mainz (Germany); Griesshammer, H. W. [Center for Nuclear Studies, Department of Physics, George Washington University, Washington, D.C. 20052 (United States); Oezel, B. [Institut fuer Kernphysik, Technische Universitaet Darmstadt, D-64289 Darmstadt (Germany); Science and Art Faculty, Cukurova University, 01330 Adana (Turkey); Rangacharyulu, C. [Department of Physics, University of Saskatchewan, Saskatoon, S7N 5E2 (Canada)

2008-05-02

19

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.

2014-05-01

20

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

21

Deuteron breakup at 2. 1 and 1. 25 GeV  

SciTech Connect

Inclusive differential cross section and analyzing power T/sub 20/ in A(d,p)X at 2.1 GeV and for protons at 0/sup 0/ are presented for the targets /sup 1/H, /sup 4/He, /sup 12/C, Ti, and Sn. In addition, data for /sup 1/H at 1.25 GeV are also shown. For all targets the cross-section data show a similarity in shape when plotted as a function of q, the proton momentum in the deuteron frame, each target exhibiting a shoulder near q = 0.30--0.35 GeV/c. Likewise, T/sub 20/ values are largely independent of the target's A value. When compared with higher-energy data for /sup 12/C(d,p)X, the new results establish the universality of the shoulder over the energy range 1.25--7.4 GeV, as well as the energy independence of T/sub 20/. The /sup 1/H(d,p)X data are compared with the results of a nonrelativistic calculation of the six lowest-order graphs of the process using elastic, on-shell NN amplitudes and the Paris NN potential deuteron wave function. The calculated cross sections have no shoulder at either of the two energies of this experiment; the observed behavior of T/sub 20/ is reproduced qualitatively only. Comparisons with /sup 2/H(p,2p) and /sup 2/H(e,e'p) data are made and various possible origins for the anomalous shoulder discussed, including ..pi.. rescattering, ..delta.. excitation, and a six quark component in the deuteron.

Punjabi, V.; Perdrisat, C.F.; Ulmer, P.; Lyndon, C.; Yonnet, J.; Beurtey, R.; Boivin, M.; Plouin, F.; Didelez, J.P.; Frascaria, R.; and others

1989-02-01

22

Vector and tensor analyzing powers in deuteron-proton breakup at 130 MeV  

NASA Astrophysics Data System (ADS)

High-precision data for vector and tensor analyzing powers for the H1(d?,pp)n reaction at a 130-MeV deuteron beam energy have been measured over a large part of the phase space. Theoretical predictions based on various approaches to describe the three nucleon (3N) system reproduce very well the vector analyzing power data and no three-nucleon force effect is observed for these observables. Tensor analyzing powers are also very well reproduced by calculations in almost the whole studied region, but locally certain discrepancies are observed. For Axy such discrepancies usually appear, or are enhanced, when model 3N forces, TM99 or Urbana, are included. Problems of all theoretical approaches with describing Axx and Ayy are limited to very small kinematical regions, usually characterized by the lowest energy of the relative motion of the two protons.

Stephan, E.; Kistryn, St.; Sworst, R.; Biegun, A.; Bodek, K.; Ciepa?, I.; Deltuva, A.; Epelbaum, E.; Fonseca, A. C.; Golak, J.; Kalantar-Nayestanaki, N.; Kamada, H.; Kiš, M.; K?os, B.; Kozela, A.; Mahjour-Shafiei, M.; Micherdzi?ska, A.; Nogga, A.; Skibi?ski, R.; Wita?a, H.; Wro?ska, A.; Zejma, J.; Zipper, W.

2010-07-01

23

The Proton-Deuteron Break-Up Process in a Three-Dimensional Approach  

NASA Astrophysics Data System (ADS)

The pd break-up amplitude in the Faddeev scheme is calculated by employing a three-dimensional method without partial wave decomposition (PWD). In the first step and in view of higher energies only the leading term is evaluated and this for the process d(p,n)pp. A comparison with the results based on PWD reveals discrepancies in the cross section around 200 MeV. This indicates the onset of a limitation of the partial wave scheme. Also around 200 MeV relativistic effects are clearly visible and the use of relativistic kinematics shifts the cross section peak to where the experimental peak is located. The theoretical peak height, however, is wrong and calls first of all for the inclusion of rescattering terms, which are shown to be important in a nonrelativistic full Faddeev calculation in PWD.

Fachruddin, Imam; Elster, Charlotte; Glöckle, Walter

24

Coulomb breakup mechanism of neutron drip-line nuclei  

SciTech Connect

The mechanism of the Coulomb breakup reaction of the projectile nuclei with neutron halo structure is investigated by the time-dependent Schroedinger equation in three-dimensional space. The time evolution of the internal wave function between the core nucleus and the halo neutron is calculated in the target Coulomb field treated as the time-dependent external field. Calculations are done for the [sup 11]Be+[sup 208]Pb system for which an experiment has been done recently. The calculated results support the picture of free-particle breakup mechanism: Only the core nucleus is affected by the target Coulomb field, while the halo neutron moves independently. As a result, we obtain large transverse and small longitudinal difference in the relative velocity between the core and the neutron after the breakup. The origin of the longitudinal velocity difference observed experimentally is left unresolved in our approach.

Kido, T. (Graduate School of Science and Technology, Niigata University, Niigata 950-21 (Japan)); Yabana, K.; Suzuki, Y. (Department of Physics, Niigata University, Niigata 950-21 (Japan))

1994-09-01

25

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

26

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

27

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

NASA Astrophysics Data System (ADS)

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

Luong, D. H.; Dasgupta, M.; Hinde, D. J.; du Rietz, R.; Rafiei, R.; Evers, M.; Lin, C. J.; Wakhle, A.; Ramachandran, K.; Carter, I. P.; Diaz-Torres, A.

2013-12-01

28

Deuteron breakup pd->(pp){sub s}n with forward emission of a fast {sup 1}S{sub 0} diproton  

SciTech Connect

The deuteron breakup reaction pd->(pp){sub s}n, where (pp){sub s} is a fast proton pair emitted in forward direction with small excitation energy E{sub pp}<3 MeV, has been studied at proton beam energies of 0.5-2.0 GeV using the ANKE spectrometer at COSY-Juelich. The differential c.m. cross sections are measured in complete kinematics and provide angular distributions of the neutron emission angle in the range theta{sub n}=168 deg. - 180 deg., the dependence on beam energy at theta{sub n}=180 deg., angular distributions of the direction of the proton in the pp rest frame, and distributions of the excitation energy E{sub pp} of the proton pair. The obtained data are analyzed on the basis of theoretical models previously developed for the pd->dp process in a similar kinematics and properly modified for the diproton channel in pd->(pp){sub s}n. It is shown that the measured observables are highly sensitive to the short-range part of the nucleon-nucleon interaction.

Dymov, S.; Yaschenko, S. [Physikalisches Institut, Universitaet Erlangen-Nuernberg, D-91058 Erlangen (Germany); Laboratory of Nuclear Problems, JINR, RU-141980 Dubna (Russian Federation); Komarov, V.; Macharashvili, G.; Uzikov, Yu.; Azarian, T.; Kulikov, A.; Kurbatov, V.; Merzliakov, S.; Zalikhanov, B.; Zhuravlev, N. [Laboratory of Nuclear Problems, JINR, RU-141980 Dubna (Russian Federation); Imambekov, O. [Laboratory of Nuclear Problems, JINR, RU-141980 Dubna (Russian Federation); Kazakh National University, KZ-050038, Almaty (Kazakhstan); Buescher, M.; Hartmann, M.; Hejny, V.; Kacharava, A.; Nekipelov, M.; Ohm, H.; Rathmann, F.; Seyfarth, H. [Institut fuer Kernphysik and Juelich Centre for Hadron Physics, Forschungszentrum Juelich, D-52425 Juelich (Germany)

2010-04-15

29

Physical Mechanism of Substorm Breakup Arcs and Onset  

NASA Astrophysics Data System (ADS)

Observations show that Pi 2 waves are excited prior to the appearance of breakup auroral arcs that break up after substorm expansion onset. The Pi2 waves and the breakup arcs are modeled by the Kinetic Ballooning Instability (KBI), which is destabilized by plasma pressure gradient and magnetic field curvature in the high beta magnetic well region in the near-Earth plasma sheet. Our model is based on the theoretical analysis and numerical solutions of the gyrokinetic mode equations for late growth phase 3D magnetospheric equilibria. The results show that the KBI has a real frequency associated with the ion magnetic drift frequency, which is in the Pi2 frequency range, and the most unstable KBI has an azimuthal mode number on the order of 200- 300. The theoretical KBI features are consistent with observational features in both the aurora breakup arcs and the near-Earth plasma sheet. Comparison between our KBI model and substorm breakup arc observations by FORMOSAT-2's ISUAL and THEMIS All Sky Imagers will be presented.

Peng, A.; Cheng, C.; Zaharia, S.; Gorelenkov, N.; Chang, T.

2008-12-01

30

3D thermo-mechanical models of continental breakup and transition from rifting to continental break-up and spreading  

NASA Astrophysics Data System (ADS)

We conducted high-resolution 3D thermo-mechanical numerical modeling experiments to explore evolution and styles of plume-activated rifting in presence of preexisting far-field tectonic stress/strain field and tectonic heritage (in form of cratonic blocks embedded in «normal lithosphere»). The experiments demonstrate strong dependence of rifting style on preexisting far-field tectonic stress/strain field and initial thermo-rheological profile, as well as on the tectonic heritage. The models with homogeneous lithosphere demonstrate strongly non-linear impact of far-field extension rates on timing of break-up processes. Experiments with relatively fast far-field extension (6 mm/y) show intensive normal fault localization in crust and uppermost mantle above the zones of plume-head emplacement some 15-20 Myrs after the onset of the experiment. When plume head material reaches the bottom of the continental crust (at ~25 Myrs), the latter is rapidly ruptured (<1 Myrs) and several steady oceanic floor spreading centers develop. Slower (3 mm/y) far-field velocities result in disproportionally longer break-up time (from 60 to 70 Myrs depending on initial isoterm at the crust bottom). Although in all experiments with homogeneous lithosphere spreading centers have similar orientation perpendicular to the direction of far-field extension, their number and spatial location are different for different extension rates and thermo-rheological structures of the lithosphere. On the contrary, in case of normal lithosphere containing embedded cratonic block, spreading zones develop symmetrically, embracing cratonic micro-plate along its long sides. Presence of cratonic blocks leads to splitting of the plume head onto initially nearly symmetrical parts, each of which flows towards beneath the craton borders. This craton-controlled distribution of plume material causes the crustal strain localization and uprise of plume material along the craton boundaries. Though there is a net tendency, in all models, of more rapid transition to spreading in case of more intensive far-field forcing, the presence of «cratonic» blocks seemingly leads to certain «acceleration» of break-up processes. Thus, lithospheric heterogeneities play important role in spatial distribution of plume-induced spreading centers and in the timing of break-up processes.

Koptev, Alexander; Burov, Evgueni; Gerya, Taras

2014-05-01

31

Momentum Distributions of Deuterons from Quasi-Elastic DD Scattering at High Energies.  

National Technical Information Service (NTIS)

The expressions for the momentum spectra of relativistic deuterons experiencing quasi-elastic (with target deuteron breakup) scattering on deuterons are obtained in the framework of the multiple nucleon-nucleon scattering model. The results of calculation...

L. S. Azhgirey S. V. Razin A. V. Tarasov V. V. Uzhinsky

1979-01-01

32

Mechanism of flow-induced biomolecular and colloidal aggregate breakup  

NASA Astrophysics Data System (ADS)

The drift-diffusion equation is first solved analytically for the dissociation rate and lifetime of a biomolecular or colloidal dimer bonded by realistic intermolecular potentials, under shear flow. Then we show using rigidity percolation concepts that the lifetime of a generic cluster formed under shear is controlled by the typical lifetime of a single bond in its interior. The latter, however, is also affected by collective stress transmission from other bonds in the aggregate, which we account for by introducing a semiempirical, analytical stress transmission efficiency 0???1 calibrated on several simulation data sets. We show that aggregate breakup is a thermally activated process in which the activation energy is controlled by the interplay between intermolecular forces and the shear drift. The collective contribution to the overall shear drift term is dominant for large enough fractal aggregates, while surface erosion prevails for small and compact aggregates. The crossover between the two regimes occurs when ?N?2, where both the number of particles in the cluster N and the stress transmission efficiency ? depend on the aggregate structure through the fractal dimension df. The analytical framework for the aggregate breakup rate is in quantitative agreement with experiments and can be used in future studies in the population balance modeling of colloidal and protein aggregation.

Conchúir, Breanndán Ó.; Zaccone, Alessio

2013-03-01

33

Neutron-deuteron breakup experiment at E{sub n}=13 MeV: Determination of the {sup 1}S{sub 0} neutron-neutron scattering length a{sub nn}  

SciTech Connect

We report on results of a kinematically complete neutron-deuteron breakup experiment performed at Triangle Universities Nuclear Laboratory using an E{sub n}=13 MeV incident neutron beam. The {sup 1}S{sub 0} neutron-neutron scattering length a{sub nn} has been determined for four production angles of the neutron-neutron final-state interaction configuration. The absolute cross-section data were analyzed with rigorous three-nucleon calculations. Our average value of a{sub nn}=-18.7{+-}0.7 fm is in excellent agreement with a{sub nn}=-18.6{+-}0.4 fm obtained from capture experiments of negative pions on deuterons. We also performed a shape analysis of the final-state interaction cross-section enhancements by allowing the normalization of the data to float. From these relative data, we obtained an average value of a{sub nn}=-18.8{+-}0.5 fm, in agreement with the result obtained from the absolute cross-section measurements. Our result deviates from the world average of a{sub nn}=-16.7{+-}0.5 fm determined from previous kinematically complete neutron-deuteron breakup experiments, including the most recent one carried out at Bonn. However, this low value for a{sub nn} is at variance with theoretical expectation and other experimental information about the sign of charge-symmetry breaking of the nucleon-nucleon interaction. In agreement with theoretical predictions, no evidence was found of significant three-nucleon force effects on the neutron-neutron final-state interaction cross sections.

Gonzalez Trotter, D.E.; Meneses, F. Salinas; Tornow, W.; Howell, C.R.; Chen, Q.; Crowell, A.S.; Roper, C.D.; Walter, R.L.; Schmidt, D.; Witala, H.; Gloeckle, W.; Tang, H.; Zhou, Z.; Slaus, I. [Department of Physics, Duke University and Triangle Universities Nuclear Laboratory, Durham, NC 27708 (United States); Physikalisch-Technische Bundesanstalt, D-38116, Braunschweig (Germany); Institute of Physics, Jagiellonian University, PL-30059 Cracow (Poland); Institut fuer Theoretische Physik 2, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany); Chinese Institute of Atomic Energy, Beijing (China); Rudjer Boskovic Institute, Zagreb (Croatia)

2006-03-15

34

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

35

Coulomb breakup mechanism of neutron-halo nuclei in a time-dependent method  

SciTech Connect

The mechanism of the Coulomb breakup reactions of the nuclei with neutron-halo structure is investigated in detail. A time-dependent Schr{umlt o}dinger equation for the halo neutron is numerically solved by treating the Coulomb field of a target as an external field. The momentum distribution and the post-acceleration effect of the final fragments are discussed in a fully quantum mechanical way to clarify the limitation of the intuitive picture based on the classical mechanics. The theory is applied to the Coulomb breakup reaction of {sup 11}Be+{sup 208}Pb. The breakup mechanism is found to be different between the channels of {ital j}{sup {pi}}=1/2{sup {minus}} and 3/2{sup {minus}}, reflecting the underlying structure of {sup 11}Be. The calculated result reproduces the energy spectrum of the breakup fragments reasonably well, but explains only about a half of the observed longitudinal momentum difference. {copyright} {ital 1996 The American Physical Society.}

Kido, T.; Yabana, K.; Suzuki, Y. [Graduate School of Science and Technology, Niigata University, Niigata 950-21 (Japan)] [Graduate School of Science and Technology, Niigata University, Niigata 950-21 (Japan); [Department of Physics, Niigata University, Niigata 950-21 (Japan)

1996-05-01

36

Low energy deuteron-induced reactions on Fe isotopes  

NASA Astrophysics Data System (ADS)

The activation cross sections for production of Cr51, Mn52,54,56, Fe59, and Co55,56,57,58 radioisotopes in deuteron-induced reactions on natural Fe were measured at deuteron energies up to 20 MeV. Then, within an extended analysis of deuteron interactions with natFe, all processes from elastic scattering until the evaporation from fully equilibrated compound system have been taken into account. Following the available elastic-scattering data analysis that supports the deuteron optical potential for reaction cross sections calculations, increased attention is paid especially to the breakup (BU) mechanism and direct reactions (DR). The deuteron activation cross-section analysis is completed by consideration of the preequilibrium and compound-nucleus contributions, corrected for decrease of the total reaction cross section due to the leakage of the initial deuteron flux towards BU and DR processes. The overall agreement of the measured data and model calculations validates the description of nuclear mechanisms taken into account, particularly the strong effects of direct interactions that have still not been appropriately considered within previous deuteron activation evaluations.

Avrigeanu, M.; Avrigeanu, V.; Bém, P.; Fischer, U.; Honusek, M.; Katovsky, K.; M?n?ilescu, C.; Mrázek, J.; Šime?ková, E.; Závorka, L.

2014-04-01

37

The effect of mechanical vibration on the break-up of a cylindrical water jet in air  

Microsoft Academic Search

An account of experimental investigation into the effects of high amplitude high frequency mechanical vibration on the break-up characteristics of a liquid jet in air is given. The main phenomenon of imposed periodicity of drop spacing and uniformity of drop size is described, along with several other interesting phenomena. Graphical relationships between parameters such as vibration frequency, amplitude and break-up

L. Crane; S. Birch; P. D. McCormack

1964-01-01

38

Interplay Between Valence and Core Excitation Mechanisms in the Breakup of Halo Nuclei  

NASA Astrophysics Data System (ADS)

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 Be11 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 , 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.

Moro, A. M.; Lay, J. A.

2012-12-01

39

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

NASA Astrophysics Data System (ADS)

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

Kumar, Ravinder; Bonaccorso, Angela

2014-03-01

40

Role of channel coupling and deuteron-exchange mechanisms in anomalous alpha-particle scattering on {sup 6}Li  

SciTech Connect

A unified description of existing experimental data on alpha-particle scattering by {sup 6}Li over the broad energy range from 18 to 166 MeV was obtained with allowance for channel-coupling effects and mechanisms involving the exchange of a deuteron cluster. Angular distributions were analyzed on the basis of the optical model and the coupled reaction channels method. It was shown that the inclusion of channel coupling and the contributions from one- and two-step exchangemechanismsmakes it possible to describe special features of the behavior of differential cross sections for both elastic and inelastic scattering in a full energy range. Optimum values found for the parameters of optical potentials agree with the parameters of the global potential proposed previously for nuclei in the mass region A > 12.

Sakuta, S. B., E-mail: sakuta@dni.polyn.kiae.s [Russian Research Centre Kurchatov Institute (Russian Federation); Artemov, S.V. [Uzbek Academy of Sciences, Institute of Nuclear Physics (Uzbekistan); Burtebaev, N.; Kerimkulov, Zh. [National Nuclear Center of the Republic of Kazakhstan, Institute of Nuclear Physics (Kazakhstan); Novatsky, B. G.; Stepanov, D.N. [Russian Research Centre Kurchatov Institute (Russian Federation); Yarmukhamedov, R. [Uzbek Academy of Sciences, Institute of Nuclear Physics (Uzbekistan)

2009-12-15

41

Low and medium energy deuteron-induced reactions on {sup 63,65}Cu nuclei  

SciTech Connect

The activation cross sections of (d,p), (d,2n), (d,3n), and (d,2p) reactions on {sup 63,65}Cu were measured in the energy range from 4 to 20 MeV using the stacked-foil technique. Then, following the available elastic-scattering data analysis that provided the optical potential for reaction cross-section calculations, an increased effort was devoted to the breakup mechanism, direct reaction stripping, and pre-equilibrium and compound-nucleus cross-section calculations, corrected for the breakup and stripping decrease of the total reaction cross section. The overall agreement between the measured and calculated deuteron activation cross sections proves the correctness of the nuclear mechanism account, next to the simultaneous analysis of the elastic-scattering and reaction data.

Simeckova, E.; Bem, P.; Honusek, M.; Stefanik, M.; Fischer, U.; Simakov, S. P.; Forrest, R. A.; Koning, A. J.; Sublet, J.-C.; Avrigeanu, M.; Roman, F. L.; Avrigeanu, V. [Euratom/IPP.CR Fusion Association, Nuclear Physics Institute (NPI), 25068 Rez (Czech Republic); Euratom/FZK Fusion Association, Karlsruhe Institute of Technology (KIT), Hermann-von-Helmholtz-Platz, 1, 76344 Eggenstein-Leopoldshafen (Germany); Nuclear Data Section, International Atomic Energy Agency, A-1400 Vienna (Austria); Nuclear Research and Consultancy Group, P.O. Box 25, NL-1755 ZG Petten (Netherlands); Euratom/UKAEA Fusion Association, Culham Centre for Fusion Energy, Abingdon OX14 3DB (United Kingdom); ''Horia Hulubei'' National Institute for Physics and Nuclear Engineering, P.O. Box MG-6, RO-077125 Bucharest-Magurele (Romania)

2011-07-15

42

Description of Jet Breakup  

NASA Technical Reports Server (NTRS)

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

Papageorgiou, Demetrios T.

1996-01-01

43

The Breakup  

ERIC Educational Resources Information Center

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

Lum, Lydia

2011-01-01

44

New tectonic data constrain the mechanisms of breakup along the Gulf of California  

NASA Astrophysics Data System (ADS)

The Gulf of California is resulting from an oblique-rift system due to the separation of the Pacific and the North American plates in the ~N110E to ~N125E trend. The age, nature and orientation of strain which ended with continental break-up and incipient oceanization at ~3.6 Ma, is largely misunderstood. It is generally proposed that early stages of extension began at around 12 Ma with strain partitioning into two components: a pure ENE directed extension in the Gulf Extensional Province (which includes Sonora and the eastern Baja California Peninsula in Mexico) and a dextral strike-slip displacement west of the Baja California Peninsula along the San Benito and Tosco-Abreojos faults. This evolution would have lasted ~5-6 Ma when a new transtensional strain regime took place. This regime, with extension trending ~N110E +/-10° , led to the final break-up and the subsequent individualization of a transform-fault system and subordoned short oceanic ridges. This two-steps interpretation has recently been challenged by authors suggesting a continuous transtensional extension from 12Ma in the trend of the PAC-NAM plates Kinematic. We question both of those models in term of timing and mode of accommodation basing ourselves on field investigations in Baja California Sur (Mexico). The volcano-sedimentary formations of the Comondù group dated 25 to 20 Ma exhibit clear examples of syn-sedimentary and syn-magmatic extensive deformations. This extension, oriented N65° E+/-15° , is proposed to initiate during the Magdalena Plate subduction. It would be related to the GOC initialization. In addition to this finding, we present tectonic and dating evidences of complex detachment-faulting tectonics varying in trend and kinematics with time and space for the development to the south of Baja California Sur. The extension associated with the early detachment-fault system trended ~N110E. From ~17 Ma to, probably, ~7-8 Ma, this extension controlled the early development of the San Jose del Cabo and the coeval footwall exhumation of large Cretaceous basement blocks (such as the Sierra Laguna). This detachment tectonics is overprinted by a more recent detachment-type tectonic evolution, localized alongshore the GOC, with coeval development of Pliocene basins. At this stage, extension was trending N75E +/-10° , i.e. close to GOC-normal. We discuss the geodynamical interpretation of all those new results in terms of forces driving the obliquity of rifts.

Bot, Anna; Geoffroy, Laurent; Authemayou, Christine; Graindorge, David

2014-05-01

45

Satellite formation and merging in liquid jet breakup  

Microsoft Academic Search

An experimental investigation of the breakup of a liquid jet using high-speed motion pictures has revealed many different breakup mechanims. The influence of disturbance amplitude and frequency on the breakup mechanism for a Weber number range of 25 to 160 is considered. The jet breakup is grouped into several distinct regions, depending on the disturbance wavelength (lambda), and the undisturbed

P. Vassallo; N. Ashgriz

1991-01-01

46

2 dimensional finite stochastic breakup model of biomass particle breakup.  

PubMed

Due to the high content of cellulose, hemicellulose and lignin, the anisotropy of biomass particle in spatial structure induces the difference of mechanical properties in different directions. In this paper, based on the finite stochastic breakup model and anisotropy of biomass particles, 2-dimensional finite stochastic breakup model (2D-FSBM) of biomass particle was proposed, and the breakup process of biomass particle was investigated. In this model, the strength difference in different directions and the minimum mass ratio of a sub-particle to the parent particle were both considered. The simulation results agreed well with the experimental results in particle shapes, which indicated that 2D-FSBM could predict the breakup process of biomass particles. PMID:23232219

Guo, Qiang; Liu, Haifeng; Chen, Xueli

2013-02-01

47

Special features of the alpha induced d and polarized d breakup  

SciTech Connect

The alpha induced deuteron breakup reactions have been of interest since the three-nucleon, nucleon induced deuteron breakup, problem was addressed with tractable and predictive codes based on the Faddeev formalism and with appropriate nucleon-nucleon forces. In this paper we discuss a few special features of the alpha induced deuteron breakup reactions. Specifically, we point out the importance of the n-p tensor force in the predictions of the three-body model that fit the tensor analyzing powers better and the concommittent deterioration of the fit to the vector analyzing power caused by the inclusion of the tensor force. We suggest that there exists evidence for the /sup 1/S/sub 0/ n-p interaction, which is isospin forbidden, in both the cross section and spin observables data. Finally, we discuss certain characteristics of the p-..cap alpha.. quasifree-scattering and n-..cap alpha.. final-state-interaction processes.

Lambert, J.M.; Treado, P.A.; Koike, Y.; Slaus, I.; Correll, F.D.; Brown, R.E.; Hardekopf, R.A.; Jarmie, N.

1982-01-01

48

Satellite Breakup Risk Mitigation  

NASA Technical Reports Server (NTRS)

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

Leleux, Darrin P.; Smith, Jason T.

2006-01-01

49

Reconstructing breakup at sub-barrier energies  

NASA Astrophysics Data System (ADS)

Using a position sensitive detector array, back-angle coincidence measurements of breakup fragments at sub-barrier energies has enabled the complete characterisation of the breakup processes in the reactions of 6,7Liw ith 208PbB. reakup processes and their time-scales are identified through the reaction Q-values and the relative energy of the captured breakup fragments. The majority of breakup processes fast enough (~10-22s) to affect fusion are triggered by transfer of a neutron from 6Li, and of a proton to 7Li. These breakup mechanisms should therefore have a major contribution to the ~30% suppression of complete fusion observed at above-barrier energies.

Luong, D. H.; Hinde, D. J.; Dasgupta, M.; Evers, M.; Rafiei, R.; du Rietz, R.

2012-10-01

50

Deuteron electric polarizability  

SciTech Connect

The deuteron electric polarizability is calculated and the various contributions are analyzed theoretically. Upper limits are constructed from zero-range approximations. These analytic approximations explicate the smallness of the deviation of the exact numerical results from the zero-range approximation using no odd-parity forces and no deuteron D state.

Friar, J.L.; Fallieros, S.

1984-01-01

51

Theory of Bose-Einstein condensation mechanism for deuteron-induced nuclear reactions in micro/nano-scale metal grains and particles.  

PubMed

Recently, there have been many reports of experimental results which indicate occurrences of anomalous deuteron-induced nuclear reactions in metals at low energies. A consistent conventional theoretical description is presented for anomalous low-energy deuteron-induced nuclear reactions in metal. The theory is based on the Bose-Einstein condensate (BEC) state occupied by deuterons trapped in a micro/nano-scale metal grain or particle. The theory is capable of explaining most of the experimentally observed results and also provides theoretical predictions, which can be tested experimentally. Scalabilities of the observed effects are discussed based on theoretical predictions. PMID:19440686

Kim, Yeong E

2009-07-01

52

Compact LINAC for deuterons  

SciTech Connect

We are developing a compact deuteron-beam accelerator up to the deuteron energy of a few MeV based on room-temperature inter-digital H-mode (IH) accelerating structures with the transverse beam focusing using permanent-magnet quadrupoles (PMQ). Combining electromagnetic 3-D modeling with beam dynamics simulations and thermal-stress analysis, we show that IHPMQ structures provide very efficient and practical accelerators for light-ion beams of considerable currents at the beam velocities around a few percent of the speed of light. IH-structures with PMQ focusing following a short RFQ can also be beneficial in the front end of ion linacs.

Kurennoy, S S [Los Alamos National Laboratory; O' Hara, J F [Los Alamos National Laboratory; Rybarcyk, L J [Los Alamos National Laboratory

2008-01-01

53

Crossover between Rayleigh-Taylor instability and turbulent cascading atomization mechanism in the bag-breakup regime.  

PubMed

The question of whether liquid atomization depends on instability dynamics (through refinements of Rayleigh-Plateau, Rayleigh-Taylor, or Kelvin-Helmholtz mechanisms) or on turbulent cascades, as suggested by Richardson and Kolmogorov, is still open. In this paper, experimental results reveal that both mechanisms are needed to explain the probability density functions (PDFs) of the droplets in a spray obtained from an industrial fan spray nozzle. Instability of Rayleigh-Taylor type controls the size of the largest droplets while the smallest droplets follow a PDF given by a turbulent cascading mechanism characterized by a log-Lévy stable law that has a stability parameter equal to 1.70. This value is very close to the inverse value of the Flory exponent and can be related to a recent model developed by N. Rimbert for intermittency modeling stemming from self-avoiding random vortex stretching. PMID:21867315

Rimbert, Nicolas; Castanet, Guillaume

2011-07-01

54

Systematic analysis of deuteron induced reactions within the CDCC framework  

SciTech Connect

We present an analysis of deuteron induced reactions on spherical and near-spherical targets with incident energies from 3 MeV to 200 MeV. This analysis has been performed within the Continuum Discretized Coupled Channels formalism using two parameterizations for the nucleon-target optical potentials, namely CH89 and Koning-Delaroche. The calculated differential cross sections and reaction ones have been compared with experimental data. A satisfactory agreement is observed and calculations show that for the heaviest targets the Coulomb breakup can not be neglected at low incident energies.

Chau Huu-Tai, P. [CEA/DAM/DIF/DPTA/SPN/LMED BP12-F-91680 Bruyeres-le-Chatel (France)

2006-08-14

55

Modeling of drop breakup in the bag breakup regime  

NASA Astrophysics Data System (ADS)

Several analytic models for predicting the drop deformation and breakup have been developed over the last three decades, but modeling drop breakup in the bag-type regime is less reported. In this Letter, a breakup model has been proposed to predict the drop deformation length and breakup time in the bag-type breakup regime in a more accurate manner. In the present model, the drop deformation which is approximately as the displacement of the centre of mass (c. m.) along the axis located at the centre of the drop, and the movement of c. m. is obtained by solving the pressure balance equation. The effects of the drop deformation on the drop external aerodynamic force are considered in this model. Drop breakup occurs when the deformation length reaches the maximum value and the maximum deformation length is a function of Weber number. The performance and applicability of the proposed breakup model are tested against the published experimental data.

Wang, C.; Chang, S.; Wu, H.; Xu, J.

2014-04-01

56

A Mesonic Deuteron Analog  

NASA Astrophysics Data System (ADS)

Using the Los Alamos Model Potential first applied to nuclear quark structure, we calculate the binding energy and quark structure of a B-meson and a D-meson. Aside from the spin differences, the larger than nucleon masses and complete absence of quark Pauli repulsive effects leads to a much smaller, but otherwise deuteron-like state, wherein pion exchange is present but not the dominant contribution to the binding of the state.

Goldman, Terrence; Silbar, Richard

2013-04-01

57

Cross-section measurements of the space-star configuration in N-D breakup at 13.0 MeV  

SciTech Connect

In this paper we present results for kinematically complete cross-section measurements of the space-star configuration in neutron-deuteron breakup for an incident neutron energy of 13.0 MeV. These data are a subset of the results obtained in a recent experiment in which cross sections for 46 configurations were measured simultaneously. The experimental techniques are described. These new data are in good agreement with previous n-d data but differ significantly from both rigorous n-d calculations and proton-deuteron breakup data. {copyright} {ital 1995} {ital American} {ital Institute} {ital of} {ital Physics}.

Setze, H.R.; Howell, C.R.; Braun, R.T.; Gonzalez Trotter, D.E.; Hussein, A.H.; Roper, C.D.; Salinas, F.; Slaus, I.; Tornow, W.; Vlahovic, B.; Walter, R.L. [Department of Physics, Duke University, Triangle Universities Nuclear Laboratory, Box 90308, Durham, North Carolina 27708 (United States); Mertens, G. [University of Tuebingen, Tuebingen (Germany); Lambert, J.M. [Department of Physics, Georgetown University, Washington, D.C. 20057 (United States); Witala, H. [Institute of Physics, Jagellonian University, Reymonta 4, PL-30059 Cracow (Poland)

1995-05-10

58

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

59

Investigations of the Capture of Protons and Deuterons by Deuterons  

Microsoft Academic Search

The capture of protons and deuterons by deuterons has been studied up to energies of 1.5 Mev. An upper limit of Å10-31 cm2 has been found for the D(dgamma) reaction near 1 Mev. The gamma-radiation from D(pgamma) has been found to have an angular distribution obeying a 2theta law. The cross section of the reaction is given empirically from 0.5

W. A. Fowler; C. C. Lauritsen; A. V. Tollestrup

1949-01-01

60

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

61

Momentum-space calculation of proton-deuteron scattering including Coulomb and irreducible three-nucleon forces  

NASA Astrophysics Data System (ADS)

Three-nucleon scattering equations with irreducible three-nucleon force are solved in momentum-space. The Coulomb interaction between the two protons is included using the method of screening and renormalization. The need for the renormalization of the scattering amplitudes is demonstrated numerically. The Coulomb and Urbana IX three-nucleon force effects on the observables of elastic proton-deuteron scattering and breakup are studied.

Deltuva, A.

2009-12-01

62

Drop breakup in the flow through fixed fiber beds: An experimental and computational investigation  

NASA Astrophysics Data System (ADS)

Dilute fixed fiber beds provide a model system for studying drop dynamics in disordered flows. Fluctuations about the mean uniform velocity are generated by fiber elements within the media, and the disturbance velocities far from any single fiber (at distances on the order of the pore size) have been predicted to be strong in terms of drop deformation and breakup by Mosler and Shaqfeh [Phys. Fluids 9, 5 (1997)]. In this work, we focus on the importance of near-field interactions, or the flow close to individual fibers. We present experimental observations of drop deformation and breakup during flow through a dilute bed of randomly placed fibers. We found breakup to result from only close interactions with fibers and describe two near-field breakup mechanisms which we term ``graze'' and ``hairpin'' processes. In addition, we present the breakup probability through the experimental fiber bed as a function of the appropriate Capillary number Ca. To better understand the near-field interactions, we used the boundary integral method to determine drop shape evolution in the flow around an infinite fiber within a porous medium, and our simulations capture the breakup mechanisms observed during experiments. To compare with experimental breakup probabilities, we have defined a critical offset for breakup during flow past a fiber and assuming straight center-of-mass trajectories, calculated breakup probabilities based on this simple model. These predictions compare well with the experimental measurements for Ca>=2.

Patel, Prateek D.; Shaqfeh, Eric S. G.; Butler, Jason E.; Cristini, Vittorio; B?awzdziewicz, Jerzy; Loewenberg, Michael

2003-05-01

63

Measurement of the yield of spectator protons at zero emission angle in deuteron stripping in carbon at 8. 9 GeV/c  

SciTech Connect

The invariant cross section for stripping of the deuteron in a carbon target has been measured at a deuteron momentum of 8.9 GeV/c. The cross section for zero-angle emission of the stripping proton has been found to be (E/p/sup 2/)(d/sup 2/sigma/dpd..cap omega..)(theta = 0, p = (1/2) p/sub d/) = 281 +- 9 bx c/sup 3//GeV/sup 2/x sr, in agreement with the value calculated from the Bertocci-Treleani model for deuteron fragmentation. The cross section calculated by the same method, but with the Nissen-Meyer orthogonalization method used for the wave functions of the initial deuteron and the np system produced in its breakup, is 1.4 times the measured cross section.

Ableev, V.G.; Vorob'ev, G.G.; Zaporozhets, S.A.; Nomofilov, A.A.; Nikitin, D.; Piskunov, N.M.; Sitnik, I.M.; Strokovskii, E.A.; Strunov, L.N.; Filipkowski, A.

1983-01-01

64

Point-form analysis of elastic deuteron form factors  

NASA Astrophysics Data System (ADS)

The point form of relativistic quantum mechanics is applied to the analysis of elastic electron-deuteron scattering and the calculation of deuteron form factors. Of the three forms of relativistic dynamics described by Dirac in 1949 (in Reviews of Modern Physics, volume 21, pages 392-399), the point form has not yet been investigated or used as frequently as the front and instant forms. Previous work in the point form has succeeded in describing the pion form factor; this work will now address in addition a somewhat more complicated two-body problem, the description of the deuteron's electromagnetic structure. A point-form spectator approximation (PFSA) is defined and applied (using two well-tested nucleon-nucleon interactions, the Argonne v 18 and the Reid '93, and two frequently used nucleon form factor parameterizations, those of Gari- Krümpelmann and Mergell-Meissner-Drechsel) to describe the electromagnetic form factors and elastic scattering observables of the deuteron. Comparisons show that the results are nearly identical for both nucleon- nucleon interactions, but differ significantly depending on the nucleon form factor parameterization chosen, particularly on the neutron electric form factor. The PFSA, like impulse approximations, relativistic or not, provides an accurate description of elastic deuteron observables up to momentum transfers of 0.5 GeV2. In the range of intermediate momentum transfer, the PFSA falls only slightly short of describing the deuteron scattering observables A(Q2) and T 20(Q2), but predicts a zero in B(Q2) roughly half a GeV2 before experiment would suggest. These results, however, are typical of many (but not all) impulse-like approximations in other forms. That, the point-form spectator approximation can describe the deuteron as well as other forms do suggests that two- body currents, straightforwardly handled in the point form, may in future work be added to accurately describe the deuteron's structure at high momentum transfers. It has the advantage that it easily extends to arbitrary spins. This work confirms that point-form quantum mechanics is a consistent, Lorentz-covariant treatment well-suited to addressing few-body problems in physics.

Allen, Thomas Wayne

2000-12-01

65

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

66

An experimental study of the effects of liquid properties on the breakup of a two-dimensional liquid sheet  

NASA Astrophysics Data System (ADS)

The breakup of a liquid sheet is of fundamental interest in the atomization of liquid fuels. The present study explores the breakup of a two-dimensional liquid sheet in the presence of co-flow air with emphasis on the extent to which liquid properties affect breakup. Three liquids, selected with varying values of viscosity and surface tension, are introduced through a twin-fluid, two-dimensional nozzle. A pulsed laser imaging system is used to determine the sheet structure at breakup, the distance and time to breakup, and the character of the ligaments and droplets formed. Experiments are conducted at two liquid flow rates with five flow rates of co-flowing air. Liquid properties affect the residence time required to initiate sheet breakup, and alter the time and length scales in the breakup mechanism.

Stapper, B. E.; Sowa, W. A.; Samuelsen, G. S.

1990-06-01

67

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

68

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

69

Fusion and Breakup of Weakly Bound Nuclei  

SciTech Connect

We discuss the influence of the breakup process of weakly bound nuclei on the fusion cross section. The complete fusion for heavy targets is found to be suppressed due to the incomplete fusion following the breakup, whereas this effect is negligible for light targets. The total fusion cross sections for stable projectiles are not affected by the breakup process, whereas it is suppressed for halo projectiles. The non capture breakup is the dominant process at sub-barrier energies.

Gomes, P. R. S.; Lubian, J. [Instituto de Fisica, Universidade Federal Fluminense, Niteroi, R.J., 24210-340 (Brazil); Padron, I. [Instituto de Fisica, Universidade Federal Fluminense, Niteroi, R.J., 24210-340 (Brazil); CEADEN, P.O. Box 6122, Havana (Cuba); Crema, E.; Chamon, L. C.; Hussein, M. S. [Instituto de Fisica, Universidade de Sao Paulo, 05315-970, Sao Paulo, S.P. (Brazil); Canto, L. F. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Rio de Janeiro, R.J., 21941-972 (Brazil)

2006-08-14

70

Neutron-Neutron Scattering Length Determinations Using nd Breakup in Different Nucleon Detection Geometries  

NASA Astrophysics Data System (ADS)

Significant differences in the value for the ^1S0 neutron-neutron (nn) scattering length(ann) have been obtained with neutron-deuteron (nd) breakup measurements made using different detection geometries [1,2]. We report the results of a new determination of ann made using the nd breakup reaction in recoil proton geometry. The measurements were made at the Triangle Universities Nuclear Laboratory (TUNL) with a neutron beam energy of 19.0 MeV. The momenta of the recoil proton and one of the outgoing neutrons were measured at mean angles of ?p= 45.0^o and ?n= 52.1^o, respectively. Details of the experiment and analysis will be presented, and results will be discussed. [4pt] [1] D.E. Gonález Trotter et al., Phys. Rev. C 73, 034001 (2006).[0pt] [2] V. Huhn et al., Phys. Rev. Lett. 85, 1190 (2000).

Howell, C. R.; Crowell, A. S.; Deng, J.; Esterline, J. H.; Kiser, M. R.; Macri, R. A.; Tajima, S.; Tornow, W.; Crowe, B. J., III; Pedroni, R. S.; von Witsch, W.; Wita?a, H.

2009-10-01

71

Axial observables in d-->p--> breakup and the three-nucleon force.  

PubMed

We have measured three axial polarization observables in d-->p--> breakup with a polarized 270 MeV deuteron beam on a polarized proton target. Axial observables are zero by parity conservation in elastic scattering but can be easily observed in the breakup channel at the present energy. Based on a symmetry argument, the sensitivity of these observables to the three-nucleon force might be enhanced. Calculations without three-nucleon force are in fair agreement with our measurement, indicating that the expected sensitivity of axial observables to the three-nucleon force is not confirmed. Including a three-nucleon force in the calculation does not improve the agreement with the data. PMID:15447333

Meyer, H O; Whitaker, T J; Pollock, R E; Von Przewoski, B; Rinckel, T; Doskow, J; Kuro?-Zo?nierczuk, J; Thörngren-Engblom, P; Pancella, P V; Wise, T; Lorentz, B; Rathmann, F

2004-09-10

72

Incoherent ?-electroproduction off the deuteron  

NASA Astrophysics Data System (ADS)

Incoherent eta meson electroproduction off the deuteron is studied in the impulse approximation (IA) or spectator model in which the eta production takes place on a single nucleon inside the deuteron while the other nucleon acts as a spectator only, i.e., neglecting eta rescattering on the spectator nucleon and nucleon two-body effects. The elementary operator for eta electroproduction off a nucleon is taken from the MAID analysis. The semi-exclusive structure functions, determining the differential cross section of the outgoing eta meson without detection of the final nucleons, are calculated and their dependence on the squared four momentum transfer K and the lab energy transfer k0lab are studied.

Tammam, Mahmoud

2009-10-01

73

Solar Wind-Magnetosphere Coupling Influences on Pseudo-Breakup Activity  

NASA Technical Reports Server (NTRS)

Pseudo-breakups are brief, localized aurora[ arc brightening, which do not lead to a global expansion, are historically observed during the growth phase of substorms. Previous studies have demonstrated that phenomenologically there is very little difference between substorm onsets and pseudo-breakups except for the degree of localization and the absence of a global expansion phase. A key open question is what physical mechanism prevents a pseudo-breakup form expanding globally. Using Polar Ultraviolet Imager (UVI) images, we identify periods of pseudo-breakup activity. Foe the data analyzed we find that most pseudo-breakups occur near local midnight, between magnetic local times of 21 and 03, at magnetic latitudes near 70 degrees, through this value may change by several degrees. While often discussed in the context of substorm growth phase events, pseudo-breakups are also shown to occur during prolonged relatively inactive periods. These quiet time pseudo-breakups can occur over a period of several hours without the development of a significant substorm for at least an hour after pseudo-breakup activity stops. In an attempt to understand the cause of quiet time pseudo-breakups, we compute the epsilon parameter as a measure of the efficiency of solar wind-magnetosphere coupling. It is noted that quiet time pseudo-breakups occur typically when epsilon is low; less than about 50 GW. We suggest that quiet time pseudo-breakups are driven by relatively small amounts of energy transferred to the magnetosphere by the solar wind insufficient to initiate a substorm expansion onset.

Fillingim, M. O.; Brittnacher, M.; Parks, G. K.; Germany, G. A.; Spann, J. F.

1998-01-01

74

Nonlocality in Deuteron Stripping Reactions  

NASA Astrophysics Data System (ADS)

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 ˜40MeV from the “Ed/2” value frequently used in the analysis of experimental data, where Ed is the incident deuteron energy. The “Ed/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.

Timofeyuk, N. K.; Johnson, R. C.

2013-03-01

75

Drop Breakup in Fixed Bed Flows as Model Stochastic Flow Fields  

NASA Technical Reports Server (NTRS)

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

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

1999-01-01

76

Deuteron and Anti-deuteron Production in $e^{+}e^{-}$ Collisions at the Z resonance  

Microsoft Academic Search

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^-6 per hadronic Z decay in the anti-deuteron momentum range from 0.62 to 1.03 GeV\\/c. The coalescence parameter B_2, which characterizes the likelihood of anti-deuteron production, is measured to be 0.0033+-0.0013 GeV^2 in Z

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

2004-01-01

77

Bubble breakup phenomena in a venturi tube  

NASA Astrophysics Data System (ADS)

Microbubble has distinguished characteristics of large surface area to unit volume and small buoyancy, and it has advantages in many engineering fields. Recently microbubble generators with low energy and high performance are required to wide applications. In the present study, we propose one new effective technique to generate tiny bubbles with less than 200 ?m diameter utilizing venturi tube under high void fraction condition. The objective of the present study is to elucidate the mechanism of bubble breakup phenomena in the venturi tube and to clarify the effects of parameters which are necessary to realize an optimum system experimentally. Experiment was conducted with void fraction of 4% and variation of liquid velocity from 9 to 26 m/s at the throat. Under low velocity condition, bubbles which were observed with a high speed camera parted gradually in a wide region. On the contrary under high velocity condition, bubbles expanded after passing through the throat and shrank rapidly. Since the speed of sound in gas-liquid system is extremely lower than that of single-phase flow, the bubble breakup phenomenon in the venturi tube is explained as the supersonic flow in a Laval nozzle. By rapid pressure recovery in diverging area, expanding bubbles collapse violently. The tiny bubbles are generated due to the surface instability of shrinking bubbles.

Fujiwara, Akiko

2005-11-01

78

Stopping power for deuterons in partially ionized Al plasmas  

NASA Astrophysics Data System (ADS)

The stopping power of deuterons with the energies from 1keV/u to 10Mev/u in partially ionized Al plasmas is calculated based on average atom model with all the main mechanisms considered carefully. The total stopping power is found suppressed due to the inverse inelastic processes included at high temperature and the different velocity distribution for free electrons in the plasmas.

He, Bin; Wang, Jianguo

2014-04-01

79

Investigation of coalescence and breakup of bubble in packed-bed  

Microsoft Academic Search

Model of bubble interactions of breakup and coalescence in a two-dimensional packed-bed reactor has been developed for dispersed two-phase flow conditions. Image processing techniques are used to study dominant bubble mechanisms at pore level under the bubbly flow regime. Bubble breakup and coalescence are identified as dominant mechanisms from analysis using a large number of image samples. Two types of

Daeseong Jo

2010-01-01

80

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

81

3D Thermo-mechanical modelling of a stretched continental lithosphere containing localized low-viscosity anomalies (the soft-point theory of plate break-up)  

NASA Astrophysics Data System (ADS)

We present numerical models of extensional visco-elasto-plastic 3D continental lithosphere containing weaker areas within its mantle section. We aim at understanding the 3D crustal structure of volcanic passive margins that is characterized by both across-strike and along-strike finite strain gradients, with maxima around central igneous complex or their feeding magma reservoirs. It is suggested that localized hot melting zones within the lithosphere act as mechanical soft points and result in the local focusing of extension. To test this hypothesis 3D thermo-mechanical models of extensional continental lithosphere containing thermally induced soft points are implemented. Results show that crustal extension initiates and is focused over soft points in the mantle, reproducing the tectonic segmentation and zig-zag pattern of VPMs (volcanic passive margins).

Gac, Sébastien; Geoffroy, Laurent

2009-04-01

82

Fusion suppression and sub-barrier breakup of weakly bound nuclei.  

PubMed

The mechanism for the large suppression of complete fusion in the 9Be+208Pb reaction has been investigated through measurement of sub-barrier breakup of 9Be. Excluding breakup through the 8Be ground state, whose lifetime is too long, a prompt breakup component remains, having sufficient probability to explain the observed suppression of complete fusion. This appears to be associated with interactions at the nuclear surface. The fusion suppression is predicted to be almost proportional to the charge of the target nucleus, making it most significant in reactions with heavy nuclei. PMID:12513200

Hinde, D J; Dasgupta, M; Fulton, B R; Morton, C R; Wooliscroft, R J; Berriman, A C; Hagino, K

2002-12-30

83

Electromagnetic and nuclear breakup of {sup 6}He  

SciTech Connect

The dissociation of 63 MeV/nucleon beams of {sup 6}He has been measured by observing the breakup {alpha} particles at four angles between 0{degrees} and 5{degrees} in the S320 magnetic spectrometer at MSU. Targets with a range in A from 12 to 197 were used. For each breakup event the presence or absence of one or more {gamma} rays from the target was recorded by an array of BaF{sub 2} detectors which surrounded the target. The events in coincidence with {gamma} rays are necessarily nuclear in origin, and a substantial fraction of the observed {alpha} particles do have M{gamma}>0. The data permit a quantitative study of the contribution of different breakup mechanisms by assuming that the A-dependence of breakup in the nuclear field of the target is independent of target excitation. The measurements permit determination of both the longitudinal and transverse momenta of the {alpha} particles. These are quite different depending on whether or not target {gamma} rays are observed. Fits to the momentum spectra, which are qualitatively different for light and heavy targets, will be presented.

Bush, J.E.; Balamuth, D.P.; Pohl, K.R. [and others

1995-10-01

84

Electrohydrodynamic (EHD) stimulation of jet breakup  

NASA Technical Reports Server (NTRS)

Electrohydrodynamic (EHD) excitation of liquid jets offers an alternative to piezoelectric excitation without the complex frequency response caused by piezoelectric and mechanical resonances. In an EHD exciter, an electrode near the nozzle applies an alternating Coulomb force to the jet surface, generating a disturbance which grows until a drop breaks off downstream. This interaction is modelled quite well by a linear, long wave model of the jet together with a cylindrical electric field. The breakup length, measured on a 33 micrometer jet, agrees quite well with that predicted by the theory, and increases with the square of the applied voltage, as expected. In addition, the frequency response is very smooth, with pronounced nulls occurring only at frequencies related to the time which the jet spends inside the exciter.

Crowley, J. M.

1982-01-01

85

Deuteron beam polarimetry at the nuclotron  

NASA Astrophysics Data System (ADS)

The scheme of the deuteron beam polarization measurements at Nuclotron are presented. A deuteron beam polarimeter based on the spin-asymmetry measurements in the dp-elastic scattering at large angles in center-of-mass system has been constructed at the internal target station at the Nuclotron of JINR. This polarimeter is planned to use for the measurements of the vector and tensor components of deuteron beam polarizations at the energies 270-2000 MeV simultaneously. Details on the low energy polarimeters are also discussed.

Kurilkin, P. K.; Ladygin, V. P.

2014-01-01

86

Beam breakup in a microtron  

SciTech Connect

In a microtron, the path length change from pass to pass is a fixed multiple of the RF wavelength, and the accelerating system can be reasonably well approximated as a single cavity. Under such circumstances it is possible to derive an analytical formula for the multipass beam breakup threshold current. The threshold current determined by numerical simulations agrees very well with the formula for a machine with a small number of passes. The analytic formula can serve as a useful guide in examining optics designs to improve the BBU threshold.

Yung, B.C.; Merminga, L. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

1997-06-01

87

Deuteron structure from ( p ,2 p ) and ( d , p ) breakup data at medium energies  

SciTech Connect

The results of a nonrelativistic calculation of the exclusive {sup 2}H({ital p},2{ital p}){ital n} cross section and inclusive {sup 1}H({ital {rvec d}},{ital p}){ital X} cross section and tensor analyzing power {ital T}{sub 20}, based on an expansion of the scattering {tau} matrix up to double scattering, are presented. Five different wave functions, including Reid with soft core, Paris, Bonn, Amsterdam, and Moscow, as well as two {ital NN} phase-shift amplitude sets, VPI and Saclay-Geneva, are used. Detailed comparison with the data available indicates that double scattering is indeed important for both reaction channels. For ({ital p},2{ital p}) the complete calculation removes a discrepancy of a factor of 2 to 8 present if comparison is made with the impulse approximation only; the Paris wave function gives the best results. For ({ital {rvec d}},{ital p}) the complete calculation results agree fairly well with both cross section and {ital T}{sub 20} data up to {ital q}=200 MeV/{ital c}. However, neither an enhancement in {ital d}{sup 2}{sigma}, nor an abrupt turn toward less negative {ital T}{sub 20} values, both occurring for {ital q}{gt}250 MeV/{ital c}, can be explained by the present calculation. Neither the wave functions nor the {ital NN} amplitudes used are Lorentz invariant, but the kinematics is treated relativistically. Possible causes for the discrepancy are briefly discussed.

Perdrisat, C.F. (The College of William and Mary, Williamsburg, VA (USA)); Punjabi, V. (Norfolk State University, Norfolk, VA (USA))

1990-11-01

88

Deuteron-proton breakup reaction at E/sub d/ = 7. 4 MeV  

SciTech Connect

The reaction d+p..-->..p+p+n is investigated at E/sub lab//sup d/ = 7.4 MeV. Calculations of the cross section are compared with recent kinematically complete measurements. The Coulomb potential is taken fully into account in the calculations based on the strong approximation of Moller wave operator approach.

Kroeger, H.; Nachabe, A.M.; Slobodrian, R.J.

1986-04-01

89

Breakup of Liquid Streams at High Pressures.  

National Technical Information Service (NTIS)

A theoretical and computational study of the break-up of injected liquid streams at high pressure by stress-induced cavitation is the research subject. The breakup criteria by stresses differs greatly from the traditional criterion in which a fluid cavita...

D. D. Joseph W. A. Sirignano

2006-01-01

90

Exclusive breakup measurements for {sup 9}Be  

SciTech Connect

The first exclusive breakup measurements for the nucleus {sup 9}Be are presented. Breakup via several discrete states is observed following scattering off {sup 12}C and {sup 208}Pb. The results support the prediction of a recent microscopic cluster calculation for a strong n+{sup 8}Be(2{sup +}) state component in the second excited state.

Fulton, B.R.; Cowin, R.L.; Woolliscroft, R.J.; Clarke, N.M.; Donadille, L.; Freer, M.; Leask, P.J.; Singer, S.M.; Nicoli, M.P.; Benoit, B.; Hanappe, F.; Ninane, A.; Orr, N.A.; Tillier, J.; Stuttge, L. [Department of Physics, University of York, York, Y010 5DD (United Kingdom); School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom); Universite Libre de Bruxelles, PNTPM, CP 226, B-1050 Brussels (Belgium); Institute de Physique Nucleaire, UCL, Louvain-la-Neuve (Belgium); Laboratoire de Physique Corpusclaire, ISMRA et Universite de Caen, IN2P3-CNRS, F-14050 Caen Cedex (France); Instituit de Reserches Subatomique, IN2P3-CNRS, Universite Louis Pasteur, F-67037 Strasbourg Cedex (France)

2004-10-01

91

Spring Breakup of the Delta River, Alaska.  

National Technical Information Service (NTIS)

Spring 'breakup' of snow and ice on the Delta River, Alaska, was monitored in 1967. Breakup on this braided river was a relatively calm event, with gradual development of open-water channels from headwaters to mouth. Air temperature data at Big Delta, nea...

C. W. Slaughter H. R. Samide

1971-01-01

92

Observations of auroral fading before breakup  

NASA Technical Reports Server (NTRS)

The onset of auroral breakup was studied by using a variety of instruments with time resolution of some tens of second. Rapid sequences of all-sky photographs, and fast meridian scans by photometers, show that breakup is usually preceded by moderate brightening, followed by fading of the auroral brightness lasting one or two minutes, before the actual breakup itself. This optical activity is closely correlated with the development of auroral radar echoes. Data from a magnetometer network provide some indication of a correlated response by the local auroral and ionospheric currents. Riometer recordings show a slow decrease in ionspheric radio wave absorption over a period of about ten minutes prior to breakup, with the largest decrease essentially to quiet-time values in the region of auroral fading and subsequent breakup.

Pellinen, R. J.; Heikkila, W. J.

1978-01-01

93

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

94

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

95

Negative Emotions and Behaviors are Markers of Breakup Distress  

ERIC Educational Resources Information Center

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

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

2013-01-01

96

Relativistic Description of Polarized-Deuteron Fragmentation Accompanied by the Emission of High-Transverse-Momentum Protons  

SciTech Connect

Available experimental data on the tensor analyzing power for nuclear relativistic-deuteron fragmentation accompanied by the emission of high-transverse-momentum protons are analyzed within light-front quantum mechanics. It is shown that, in contrast to calculations with standard wave functions, calculations employing the relativistic deuteron wave function obtained by V.A. Karmanov and his coauthors on the basis of light-front dynamics can explain the entire body of data without resort to additional degrees of freedom.

Azhgirey, L.S. [Joint Institute for Nuclear Research, Dubna, Moscow oblast, 141980 (Russian Federation); Yudin, N.P. [Moscow State University, Vorob'evy gory, Moscow, 119899 (Russian Federation)

2005-01-01

97

Deuteron production in p-Be interactions at 450 GeV/c and the coalescing model NA56 collaboration  

NASA Astrophysics Data System (ADS)

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 k is determined as (0.79±0.05±0.13) × 10-2. Our results disfavour the hypothesis that coalescence be the dominant mechanism for deuteron production in p + Be interactions at low pT.

Bonesini, M.

2008-05-01

98

Nanojets: Electrification, Energetics, Dynamics, Stability and Breakup.  

National Technical Information Service (NTIS)

The research during this 6 month grant was devoted to finalizing our work on the effect of electric fields on dielectric nanodroplets, as may be found during the breakup of electrified nanojets and colloidal thrusters. In our extensive molecular dynamics ...

U. Landman

2007-01-01

99

Interplay of nuclear and Coulomb effects in proton breakup from exotic nuclei  

NASA Astrophysics Data System (ADS)

This paper gives new insight to the study of dynamical effects in proton breakup as compared to neutron breakup from a weakly bound state in an exotic nucleus. To clarify and assess quantitatively which mechanism would dominate the measured observables, we study here several reaction mechanisms separately but also their total effect, including interference. These mechanisms are (i) the recoil effect of the core-target Coulomb potential which we distinguish from the direct proton-target Coulomb potential, and (ii) nuclear breakup, which consists of stripping and diffraction. Direct Coulomb breakup typically gives cross sections about an order of magnitude larger than the recoil term, and the amount of nuclear diffraction vs Coulomb depends on the target. Thus for each mechanism the absolute values of breakup cross sections and parallel momentum distributions for 8B and 17F projectiles calculated on a light and a heavy target in a range of intermediate incident energies (40A-80A MeV) are presented. Furthermore we study in detail the interference among the two Coulomb effects and nuclear diffraction. The calculation of the direct and recoil Coulomb effects separately and of their interference is the new and most relevant aspect of this paper.

Kumar, Ravinder; Bonaccorso, Angela

2012-12-01

100

Analysis of neutral rho meson decays from ultra-peripheral collisions in deuteron-gold interactions  

NASA Astrophysics Data System (ADS)

This work will investigate the production of the neutral rho meson in relativistic ultra-peripheral collisions (UPCs) of deuteron-gold (dAu) nuclei. A UPC occurs when the impact parameter for the collision of two charged particles is greater than the sum of their radii. The resulting interaction is electromagnetic in nature. These nuclei collide in the Solenoidal Tracker at RHIC (STAR), a particle detector at the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory. I will compare the kinematic distributions of variables of the produced rho mesons to Monte Carlo simulations. The Monte Carlo simulations will be used to determine the geometric acceptance and reconstruction efficiency of the SAR detector, and to help differentiate between coherent and incoherent production of rho mesons. Cross sections are presented for both exclusive photoproduction of rho mesons and photoproduction accompanied by nuclear break-up.

Hansen, Stephen

101

PROSPECTS FOR ACCELERATION OF DEUTERONS AND HELIONS.  

SciTech Connect

In order to study the spin structure of the neutron at high energy, a beam rich in polarized neutrons needs to be developed. The neutron has no charge and cannot be accelerated, so either deuterons or helions must be considered. When it comes to spin manipulation and stability of the polarization in a circular accelerator, it is the anomalous part of the magnetic moment which is important. If the anomaly is too small, then manipulation becomes difficult as in the case of deuterons--spin rotators and Siberian snakes become ineffective. {sup 3}He nuclei appear to be the easiest choice for a polarized neutron beam. In this paper I discuss the prospects for both helions and deuterons as polarized beams in RHIC or in an electron-ion collider.

MACKAY,W.W.

2007-09-10

102

Photoproduction of charged pions from the deuteron  

NASA Astrophysics Data System (ADS)

The photoproduction of the charged pions from the deuteron has been studied with the Neutral Kaon Spectrometer (NKS) and the Neutral Kaon Spectrometer 2 (NKS2) at the Research Center for Electron Photon Science, Tohoku University (ELPH) which was previously known as the Laboratory of Nuclear Science (LNS-Tohoku) using the GeV-region tagged photon beam. The total cross section for the quasi-free (QF) ?+?- photoproduction from the deuteron was measured with NKS in the energy region from 0.8 to 1.1 GeV. The cross section for the double ? excitation in the intermediate state was derived in the analysis of the non-quasi-free (NQF) process, in which two nucleons of the deuteron share the energy of the incident photon. The prospect of the measurements of double pion photoproduction with NKS2 and upgraded NKS2 is discussed.

Kanda, Hiroki

2012-02-01

103

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

SciTech Connect

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

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

2012-10-20

104

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

105

DTs-1 Deuteron Cyclotron Accelerating System.  

National Technical Information Service (NTIS)

Calculation of the main parameters of the accelerating system of the DTs-1 deuteron cyclotron for designed energy 1 MeV/turn is performed. The accelerating system is a half-wave delta-resonator with TEM-wave with vertical resonance lines. The lost power a...

A. A. Glazov E. N. Zaplatin

1986-01-01

106

Deuteron transfer in N=Z nuclei.  

PubMed

Predictions are obtained for T=0 and T=1 deuteron-transfer intensities between self-conjugate N=Z nuclei on the basis of a simplified interacting boson model which considers bosons without orbital angular momentum but with full spin-isospin structure. These transfer predictions can be correlated with nuclear binding energies in specific regions of the mass table. PMID:15904218

Van Isacker, P; Warner, D D; Frank, A

2005-04-29

107

Small Angle Elastic Electron-Deuteron Scattering.  

National Technical Information Service (NTIS)

The results of preliminary measurements of elastic electron-deuteron scattering in transverse momentum region of 0,45-1,2 fm exp -2 of the 4.5 GeV internal electron beam of the Yerevan Synchrotron are presented. A thin (CD sub 2 )sub(n) target has been us...

Y. K. Akimov K. Andert A. N. Arvanov

1974-01-01

108

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

PubMed

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

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

2011-09-01

109

Predicting Color Breakup on Field-Sequential Displays: Part 2.  

National Technical Information Service (NTIS)

We measured color-breakup thresholds for a simple field-sequential color stimulus while varying its luminance, contrast, and retinal velocity. Data analysis yielded an equation that predicts whether color breakup will be visible for specified viewing cond...

D. L. Post A. L. Nagy P. Monnier C. S. Calhoun

1998-01-01

110

Fluvial thermal erosion during the ice break-up of the Lena river (Siberia)  

NASA Astrophysics Data System (ADS)

The Lena River is one of the largest Arctic rivers; its periglacial environment implies an excessive fluvial regime and a spectacular flood occurring at the end of the winter. From the beginning of November to May, a continuous ice cover can be observed as thick as 2 m on the Lena River in Central Siberia. The break up starts around May 15 at the latitude of Yakutsk, corresponding to a flood wave coming from the South and to an increase of the water stream temperature up to 18°C. In spite of a relatively good understanding of the initial stage of the breakup period of these periglacial rivers [Beltaos and Burrell, 2002; Shen, 2003; Billfalk, 1982], only a few studies report on the role of mechanical and thermal erosion during the breakup Observations and measurements of erosion of the island heads during the first days of the ice breakup were made during breakup periods over a 4-year period (2008-2011). Here, we reassess the efficiency of the fluvial thermal erosion using both high resolution records from field measurements and modeling. We analyze the impact of the breakup on the erosional process on the head of several fluvial islands. Only a few days are enough to produce erosion rate as high as 30 m. The protective effect of the ice cover at the very beginning of the break up has been studied in more detailed during 3 field trips. These values are relatively high but are in good agreement with our modeling.

Costard, F.; Gautier, E.; Fedorov, A.; Konstantinov, P.; Dupeyrat, L.

2012-04-01

111

Coupled Map Lattice Model of Jet Breakup.  

National Technical Information Service (NTIS)

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 ana...

R. W. Minich A. J. Schwartz E. L. Baker

2001-01-01

112

1974 Ice Breakup on the Chena River.  

National Technical Information Service (NTIS)

The Corps of Engineers, Alaska District, requested USA CRREL to observe and document the ice breakup of the Chena River in the spring of 1974. The purpose was to determine the potential for ice and debris damage to the outlet structure of the proposed Che...

T. McFadden M. Stallion

1975-01-01

113

BNS damping of beam breakup instability.  

National Technical Information Service (NTIS)

The author studies BNS damping of the beam breakup instability in a simple model assuming a constant beam energy, flat bunch distribution, and a smooth transverse focusing. The model allows an analytic solution for a constant and linear wake functions. Sc...

G. V. Stupakov

1997-01-01

114

Kaon photoproduction on the deuteron at Sendai  

NASA Astrophysics Data System (ADS)

The photoproduction of K0 and ? on the deuteron was measured in order to investigate the ?n ? K0? reaction process near the threshold (E? = 0.8-1.1 GeV). K0 and ? events were clearly seen in the ?+?- and the p?- invariant mass spectra, respectively. The momentum spectra of the ?d ? K0X and the ?d ? ?X reactions were derived. Additionally, the energy dependence of the integral cross section for the ? production was also obtained. The K0 momentum spectra were in agreement with the previous results within statistical errors. The angular distribution of the ?n ? K0? reaction in the center of mass system was extracted and it had the backward distribution. The total cross section of the ?n ? K0? reaction, which was estimated by subtracting the contribution of K+? process from the ? production on the deuteron, was almost the same as that of the ?p ? K+?.

Futatsukawa, K.; Beckford, B.; Bydžzovsky, P.; Fujibayashi, T.; Fujii, Y.; Hashimoto, O.; Han, Y. C.; Hirose, K.; Hosomi, K.; Iguchi, A.; Ishikawa, T.; Kanda, H.; Kaneta, M.; Kawama, D.; Kawasaki, T.; Kiyokawa, S.; Koike, T.; Konno, O.; Maeda, K.; Maruyama, N.; Miwa, K.; Miyagi, Y.; Nakamura, S. N.; Sasaki, A.; Shirotori, K.; Sotona, M.; Suzuki, K.; Tamae, T.; Tamura, H.; Terada, N.; Tsukada, K.; Yamazaki, H.

2012-02-01

115

Deuteron threshold electrodisintegration at high momentum transfer  

NASA Astrophysics Data System (ADS)

Absolute differential cross sections for the threshold electrodisintegration of the deuteron with good resolution were measured at a laboratory scattering angle of 160° for five values of Q2 ranging from 8.66 to 42.4 fm-2. Comparisons of the data averaged over Enp from 0 to 3 MeV and from 0 to10 MeV are made with nonrelativistic meson exchange calculations. These calculations are sensitive to the nucleon electromagnetic form factors, nucleon-nucleon potential, and relativistic effects. The data are also compared with a hybrid quark-hadron model calculation that describes the deuteron as a six-quark cluster for the short range part of the interaction. Some of these calculations can describe the data reasonably well over certain ranges of Q2; however, none of these calculations can accurately describe the data over the entire measured Q2 range.

Schmitt, W. M.; Turchinetz, W.; Williamson, C. F.; Yates, T. C.; Zumbro, J. D.; Lee, K. S.; Baghaei, H.; Churchwell, S.; Hicks, R. S.; Miskimen, R.; Peterson, G. A.; Wang, K.; Bosted, P. E.; Spengos, M.; Frois, B.; Martino, J.; Platchkov, S.; Hotta, A.

1997-10-01

116

Parity-violating electron-deuteron scattering  

NASA Astrophysics Data System (ADS)

The longitudinal asymmetry due to Z0 exchange is calculated in quasielastic electron-deuteron scattering at momentum transfers \\|Q2\\|~=0.1 GeV2 relevant for the SAMPLE experiment. The deuteron and pn-scattering-state wave functions are obtained from solutions of a Schrödinger equation with the Argonne v18 potential. Electromagnetic and weak neutral one- and two-nucleon currents are included in the calculation. The two-nucleon currents of pion range are shown to be identical to those derived in chiral perturbation theory. The results indicate that two-body contributions to the asymmetry are small (~=0.2%) around the quasielastic peak, but become relatively more significant (~=3%) in the high-energy wing of the quasielastic peak.

Diaconescu, L.; Schiavilla, R.; van Kolck, U.

2001-04-01

117

The stopping of deuterons in lithium  

NASA Technical Reports Server (NTRS)

The interaction of 52 MeV deuterons with lithium was investigated, in view of the optimization of a lithium target for an intense neutron source based on the d-Li stripping reaction. The experimental results are compared with theoretical calculations obtained from an updated version of the Bragg code. This code describes in detail the interaction of charged particles with matter. Within the experimental uncertainties the theoretical results are well reproduced by the experiments.

Dierckx, R.; Kley, W.; Verga, A.; Benton, E. V.; Buschmann, J.

1985-01-01

118

Tritium Production from Lithium by Deuteron Bombardment  

Microsoft Academic Search

The tritium production cross section has been measured for Li6 bombarded by deuterons from 0.4 Mev to 4.0 Mev. The cross section rises fairly rapidly to 190 millibarns near 1 Mev, then more slowly to 290 millibarns near 4 Mev. The cross section for Li7 rises steeply from the 1.27 Mev threshold to 95 millibarns at 2.4 Mev; then more

R. L. Macklin; H. E. Banta

1955-01-01

119

[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

120

Breakup of dense colloidal aggregates under hydrodynamic stresses.  

PubMed

Flow-induced aggregation of colloidal particles leads to aggregates with fairly high fractal dimension (df approximately 2.4-3.0) which are directly responsible for the observed rheological properties of sheared dispersions. We address the problem of the decrease in aggregate size with increasing hydrodynamic stress, as a consequence of breakup, by means of a fracture-mechanics model complemented by experiments in a multipass extensional (laminar) flow device. Evidence is shown that as long as the inner density decay with linear size within the aggregate (due to fractality) is not negligible (as for df approximately 2.4-2.8), this imposes a substantial limitation to the hydrodynamic fragmentation process as compared with nonfractal aggregates (where the critical stress is practically size independent). This is due to the fact that breaking up a fractal object leads to denser fractals which better withstand stress. In turbulent flows, accounting for intermittency introduces just a small deviation with respect to the laminar case, while the model predictions are equally in good agreement with experiments from the literature. Our findings are summarized in a diagram for the breakup exponent (governing the size versus stress scaling) as a function of fractal dimension. PMID:19658503

Zaccone, Alessio; Soos, Miroslav; Lattuada, Marco; Wu, Hua; Bäbler, Matthäus U; Morbidelli, Massimo

2009-06-01

121

Shear stabilization of the capillary breakup of a cylindrical interface  

NASA Technical Reports Server (NTRS)

A cylindrical interface containing a viscous liquid set into axial motion is subject to a capillary and to a surface-wave instability. Clues from previous studies suggest that, even though both mechanisms separately are destabilizing, under certain circumstances their mutual interaction can lead to a stable interface; shear can stabilize capillary breakup. Here, an axial flow through an annular cross section bounded on the inside by a rigid rod and on the outside by a deformable interface is considered. The competition between the two mechanisms is studied through the temporal growth of infinitesimal axisymmetric and nonaxisymmetric disturbances. This examination of temporal stability shows that, indeed, for geometries corresponding to thin annular layers both instabilities can be completely suppressed (disturbances of all wavelengths decay).

Russo, Mathew J.; Steen, Paul H.

1989-01-01

122

An Examination of the Breakup of Marine Stratus: a Three-Dimensional Numerical Investigation.  

NASA Astrophysics Data System (ADS)

Cloud top entrainment instability, as a mechanism for the breakup of marine stratus, is examined with a three-dimensional, planetary boundary layer (PBL) model. Specifically, we examine the criterion developed by Randall and Deardorff; this criterion states that stratus will break up if the equivalent potential temperature gradient at cloud top becomes less than a critical value. To examine this hypothesis, we simulate a horizontally uniform stratus layer which is excited from above by small random temperature perturbations. The buoyancy instability ratio (BIR), defined as e(e)crit and computed at cloud top, is calculated locally across the domain and also averaged to define a mean value. Six cases, involving different wind speeds and above-cloud soundings, produce different initial BIRs and different breakup sequences. In general, we find that a mean BIR greater that one is a necessary condition for stratus breakup; however, we also find that the timing of breakup following achievement of the critical ratio is different from run to run. The low wind speed cases, initially most stable at cloud top, are the first to break up, while the higher wind speed (most unstable) cases require longer time to break up. We conclude that an additional mechanism is necessary to stimulate vertical motion in order to take advantage of the cloud-top entrainment instability. In our simulations, that additional stimulation comes from vertical motions generated by Rayleigh-type instability in the PBL.

Tag, Paul M.; Payne, Steven W.

1987-01-01

123

Breakup of a pendant magnetic drop.  

PubMed

We report experiments on a millimeter-sized pendant drop of ferrofluid in a horizontal magnetic field. The initial drop size is chosen just below the breakup threshold under gravity. As the magnetic field is increased, the drop tilts in order to align with the direction of the total volume force that is exerted on it: weight plus magnetic force. The breakup is controlled by a generalized Bond number based on this total force and on the radius of the neck of the drop. The evolution of drop shape turns out to be a complex process governed by many parameters such as the angle between the total force and the needle, the drop size relative to the needle radius, and the wettability of the liquid on the needle material. This suggests a certain universality, that a single value of the critical Bond number is found regardless of magnetic fluid properties and whether the force is inclined or not. PMID:23944556

Havard, N; Risso, F; Tordjeman, Ph

2013-07-01

124

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

125

Transverse quasielastic electron scattering from the deuteron  

SciTech Connect

Transverse quasielastic electron scattering cross sections have been measured for the deuteron at 180/sup 0/ for incident electron energies of 220, 270, and 320 MeV. At the quasielastic peak the four-momentum transfers squared varied from 3.4 to 6.3 fm/sup -2/. The measured spectra include the region from the elastic peak through the entire quasielastic peak. Results are compared with recent calculations incorporating meson-exchange currents and isobar configurations. At large neutron-proton separation energies, the data support the need for the inclusion of large isobar configuration components in the cross section.

Parker, B.; Hicks, R.S.; Hotta, A.; Huffman, R.L.; Peterson, G.A.; Plum, M.A.; Ryan, P.J.; Singhal, R.P.

1986-12-01

126

Fractofusion Mechanism  

Microsoft Academic Search

With respect to cold fusion, a fractofusion mechanism is investigated. Deuterons are accelerated by the electric field generated between crack surfaces in a crystal. By assuming the possible magnitude of the potential difference, we calculate the fusion rate and energy multiplication factor. The results are consistent with those of the cold fusion experiments, and the fractofusion mechanism can explain the

Tatsuoki Takeda; Tomonori Takizuka

1989-01-01

127

Source of polarised deuterons. (JINR accelerator complex)  

NASA Astrophysics Data System (ADS)

The proposed project assumes the development of a universal high-intensity source of polarized deuterons (protons) using a charge-exchange plasma ionizer. The design output current of the source will be up to 10mA for ? D+(? H+) and polarization will be up to 90% of the maximal vector (±1) and tensor (+1,-2) polarization. The project is based on the equipment which was supplied within the framework of an agreement between JINR and IUCF (Bloomington, USA). The project will be realized in close cooperation with INR (Moscow, Russia). The source will be installed in the linac hall (LU-20) and polarization of beams will be measured at the output of LU-20. The main purpose of the project is to increase the intensity of the accelerated polarized beams at the JINR Accelerator Complex up to 1010 d/pulse. Calculations and first accelerator runs have shown that the depolarization resonances are absent for the deuteron beam in the entire energy range of the NUCLOTRON. The source could be transformed into a source of polarized negative ions if necessary. The period of reliable operation without participation of the personnel should be within 1000 hours. The project should be implemented within two to two and a half years from the start of funding.

Fimushkin, V. V.; Belov, A. S.; Kovalenko, A. D.; Kutuzova, L. V.; Prokofichev, Yu. V.; Shimanskiy, S. S.; Vadeev, V. P.

2008-08-01

128

Measuring Muon Capture on the Deuteron  

NASA Astrophysics Data System (ADS)

The MuSun experiment will measure the rate of nuclear muon capture on the deuteron with a precision of 1.5%. This rate will be used to fix the low-energy constant that describes the two-nucleon weak axial current in effective field theory models. It will therefore calibrate evaluations of proton-proton fusion and neutrino-deuteron scattering. The experiment uses many of the techniques and much of the apparatus that were developed for the successful MuCap measurement of the rate of muon capture on the proton. However, to optimize the molecular kinetics, the deuterium gas is cooled to 30 K in a cryogenic time project chamber (TPC). In preparation for an upcoming high-statistics production run, a new in-vacuum cryo-preamplifier has been developed to improve the energy resolution of the TPC, and x-ray detectors to monitor the elemental purity of the target gas have been tested. These upgrades will be described, as will the significant progress that has been made in the analysis of data from the initial fall 2011 production run.

Gray, Frederick

2013-04-01

129

Two- and three-body correlations: breakup of halo nuclei  

NASA Astrophysics Data System (ADS)

Nuclear knockout reactions at relativistic energies provide a sensitive tool to determine the ground state properties of nuclei close to the drip line. Studies with kinematically complete measurements reveal the initial correlations in the reacting systems and yield spectroscopic information on the continuum states populated in the decay channel. The coincident data of charged fragments and neutrons as well allows to unveil the possible influence of the reaction mechanism to the interpretation of the measurements. Two- and three-body correlations can be observed and allow to determine the internal momentum distributions of halo nuclei as well as the assignment of spins and parities to the populated states in the intermediate systems in the breakup process.

Simon, H.; Aumann, T.; Borge, M. J. G.; Chulkov, L. V.; Elze, Th. W.; Emling, H.; For´n, C.; Geissel, H.; Hellstro¨m, M.; Jonson, B.; Kratz, J. V.; Kulessa, R.; Leifels, Y.; Markenroth, K.; Meister, M.; Mu¨nzenberg, G.; Nickel, F.; Nilsson, T.; Nyman, G.; Pribora, V.; Richter, A.; Riisager, K.; Scheidenberger, C.; Schrieder, G.; Tengblad, O.; Zhukov, M. V.

2004-04-01

130

Unstable breakup of a linearly-accelerated, dense plasma  

NASA Astrophysics Data System (ADS)

A dense plasma, accelerated by magnetic pressure, is used in an electromagnetic launcher to propel small masses. Such plasmas have been observed to disperse or fragment, and this has been related to a loss of projectile acceleration. The paper is concerned with the potential mechanisms of plasma breakup and associated limitations on projectile velocity. An unsteady, one-dimensional model of the plasma is described, which incorporates a simple correction for the effect of wall ablation. Two limiting cases are examined, one where ablation is small, and another where it is large. For the first case, it is shown that a reduction in magnetic pressure will induce a decelerating body force at the tail of the plasma. For the second case, it is shown that a high level of ablation results in the formation of a parasitic current sheet at the tail of the plasma.

Davidson, P. A.

1991-02-01

131

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

NASA Astrophysics Data System (ADS)

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.; Delferrière, O.; Girardot, P.; Jannin, J. L.; Langlois, S.; Loiseau, D.; Pottin, B.; Rousse, J.-Y.; Senée, F.

2010-02-01

132

Modeling mud flocculation using variable collision and breakup efficiencies  

NASA Astrophysics Data System (ADS)

Solution of the Winterwerp (1998) floc growth and breakup equation yields time dependent median floc size as an outcome of collision driven floc growth and shear induced floc breakage. The formulation is quite nice in that it is an ODE that yields fast solution for median floc size and can be incorporated into sediment transport models. The Winterwerp (1998) floc size equation was used to model floc growth and breakup data from laboratory experiments conducted under both constant and variable turbulent shear rate (Keyvani 2013). The data showed that floc growth rate starts out very high and then reduces with size to asymptotically approach an equilibrium size. In modeling the data, the Winterwerp (1998) model and the Son and Hsu (2008) variant were found to be able to capture the initial fast growth phase and the equilibrium state, but were not able to well capture the slow growing phase. This resulted in flocs reaching the equilibrium state in the models much faster than the experimental data. The objective of this work was to improve the ability of the general Winterwerp (1998) formulation to better capture the slow growth phase and more accurately predict the time to equilibrium. To do this, a full parameter sensitivity analysis was conducted using the Winterwerp (1998) model. Several modifications were tested, including the variable fractal dimension and yield strength extensions of Son and Hsu (2008, 2009). The best match with the in-house data, and data from the literature, was achieved using floc collision and breakup efficiency coefficients that decrease with floc size. The net result of the decrease in both of these coefficients is that floc growth slows without modification to the equilibrium size. Inclusion of these new functions allows for substantial improvement in modeling the growth phase of flocs in both steady and variable turbulence conditions. The improvement is particularly noticeable when modeling continual growth in a decaying turbulence field similar to what might be experienced in a river mouth jet. Inclusion of the functions does, however, result in problems with capturing rapid floc breakage due to a stepwise increase in turbulent shear. References Keyvani, A. (2013). Flocculation processes in river mouth fluvial to marine transitions. Ph.D. dissertation, University of Houston. Son, M. & Hsu, T.J. (2008). Flocculation model of cohesive sediment using variable fractal dimension. Environmental Fluid Mechanics, 8(1), 55-71. Son, M. & Hsu, T.J. (2009). The effect of variable yield strength and variable fractal dimension on flocculation of cohesive sediment. Water Research, 43(14), 3582 - 3592. Winterwerp, J. C. (1998). A simple model for turbulence induced flocculation of cohesive sediment. Journal of Hydraulic Research, 36(3), 309-326.

Strom, K.; Keyvani, A.

2013-12-01

133

Pangea formation and break-up  

NASA Astrophysics Data System (ADS)

The Palaeozoic was dominated by the great continent Gondwana. Other continents included Laurentia and Baltica that fused (together with Avalonia), forming Laurussia after the closure of the Iapetus Ocean, making the second largest continental entity in the Silurian. By the Carboniferous at around 320 Ma, Gondwana and Laurussia amalgamated, forming Pangea that was surrounded by the Panthalassa and Paleotethys Oceans. Pangea did not include all continental crust. For example, the South and North China Blocks were not part of Pangea at any given time and also during the Early Permian phase of Pangea assembly, the Neotethys opened, and Cimmerian terranes drifted away from the NE Gondwana margin while the Paleotethys was being subducted beneath Eurasia. An additional, unresolved question is whether Siberia was fully joined to Pangea before the eruption of the Siberian Traps (251 Ma). Practically all Permian Pangea reconstructions using palaeomagnetic data result in considerable overlap between Laurussia and Gondwana, as both are straddling the equator, and thus Gondwana must be moved sideways to avoid this overlap, and at a younger time displaced dextrally to achieve the well established starting point for Pangea break-up in the Jurassic. Octupole contributions can eliminate this overlap, but just by changing the internal fits within Laurussia and correcting all detrital sedimentary poles for inclination shallowing using a use a benchmark flattening (f) value of 0.6 (unless previously corrected using either the inclination-elongation method or anisotropy of magnetic susceptibility information) lead to an almost perfect Pangea-A type fit. Pangea break-up profoundly changed our planet, and the most important phase of break-up started when the Central Atlantic Ocean opened (ca. 195 Ma). Perhaps not coincidentally, the region where the Atlantic spreading started was preceded by the emplacement of the Central Atlantic Magmatic Province, one of the largest large igneous provinces (LIPs). Also the Early Permian opening of the Neotethys was preceded by a LIP, the Panjal Traps at around 285 Ma. Pangea was centred above the African large low shear velocity province (LLSVP) at the core-mantle boundary. The African LLSVP has been stable for at least 300 Myrs. Its edges, the plume generation zones, are favourable sites for the initiation of large plumes rising through the mantle and causing extensive upper mantle melting and eruption of LIPs that contributed to the break-up of Pangea.

Torsvik, Trond

2013-04-01

134

Deuteron stopping cross sections in transition metal hydrides  

NASA Astrophysics Data System (ADS)

The stopping cross sections of deuterons incident on deutende and tritide films of eight transition metals (Sc, Ti, Y, Zr, Gd, Er, Hf and Ta) have been determined at deuteron energies between 40 and 200 keV. The stopping cross sections were extracted from measurements of the yields of the D(d, p)T and T(d, ?)n reactions as functions of the incident deuteron energy for thick deutende and tritide films of each metal. Corrections due to elastic scattering effects and surface oxides are incorporated in the analysis. Deviations from Bragg's rule are found in these materials and these deviations are discussed.

Malbrough, D. J.; Brice, D. K.; Cowgill, D. F.; Borders, J. A.; Shope, L. A.; Harris, J. M.

1987-11-01

135

3H production via neutron-neutron-deuteron recombination  

NASA Astrophysics Data System (ADS)

We study the recombination of two neutrons and deuteron into neutron and 3H using realistic nucleon-nucleon potential models. Exact Alt, Grassberger, and Sandhas equations for the four-nucleon transition operators are solved in the momentum-space framework using the complex-energy method with special integration weights. We find that at astrophysical or laboratory neutron densities the production of 3H via the neutron-neutron-deuteron recombination is much slower as compared to the radiative neutron-deuteron capture. We also calculate neutron-3H elastic and total cross sections.

Deltuva, A.; Fonseca, A. C.

2013-01-01

136

Cross section and T/sub 20/ in 0/sup 0/ deuteron breakup at 2. 1 GeV  

SciTech Connect

Cross sections and T/sub 20/ analyzing powers for dA..-->..pX are presented. A shoulder in the cross section previously reported at higher energies and for carbon is observed for H, C, and Ti at the same d-c.m.-frame proton momentum q = 0.35 GeV/c. At q<0.2 GeV/c both cross-section and T/sub 20/ data depend only weakly upon the target atomic number A. Calculations in the plane-wave impulse approximation with several NN wave functions, and with either a ..delta delta.. or a six-quark component added, are discussed.

Perdrisat, C.F.; Punjabi, V.; Lyndon, C.; Yonnet, J.; Beurtey, R.; Boivin, M.; Boudard, A.; Didelez, J.P.; Frascaria, R.; Reposeur, T.; and others

1987-12-21

137

University Students' Experiences of Nonmarital Breakups: A Grounded Theory  

ERIC Educational Resources Information Center

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

Hebert, Sarah; Popadiuk, Natalee

2008-01-01

138

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

139

Pangea's complex breakup: A new rapidly changing stress field model  

Microsoft Academic Search

Over the years numerous proposals have been presented describing the relationship between the Central Atlantic Magmatic Province (CAMP) and the break-up of Pangea. Recent proposals have focused on refuting the original proposal of a mantle plume origin for the large igneous province and attendant dikes, and instead propose an upper mantle or passive cause for the break-up and CAMP. In

E. K. Beutel; S. Nomade; A. K. Fronabarger; P. R. Renne

2005-01-01

140

Some features of spray breakup in effervescent atomizers  

Microsoft Academic Search

The near orifice spray breakup at low GLR (gas to liquid ratio by mass) values in an effervescent atomizer is studied experimentally using water as a simulant and air as atomizing gas. From the visualizations, the near orifice spray structures are classified into three modes: discrete bubble explosions, continuous bubble explosions and annular conical spray. The breakup of the spray

Hrishikesh P. Gadgil; B. N. Raghunandan

2010-01-01

141

Some features of spray breakup in effervescent atomizers  

Microsoft Academic Search

The near orifice spray breakup at low GLR (gas to liquid ratio by mass) values in an effervescent atomizer is studied experimentally using water as a simulant and air as atomizing gas. From the visualizations, the near orifice spray structures are classified into three modes: discrete bubble explosions, continuous bubble explosions and annular conical spray. The breakup of the spray

Hrishikesh P. Gadgil; B. N. Raghunandan

2011-01-01

142

Breakup Effects on University Students' Perceived Academic Performance  

ERIC Educational Resources Information Center

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

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

2012-01-01

143

Examining of the Collision Breakup Model between Geostationary Orbit Objects  

Microsoft Academic Search

This paper will examine the applicability of the hypervelocity collision model included in the NASA standard breakup model 2000 revision to low-velocity collisions possible in space, especially in the geosynchronous regime. The analytic method used in the standard breakup model will be applied to experimental data accumulated through low-velocity impact experiments performed at Kyushu Institute of Technology at a velocity

Hidehiro Hata; Toshiya Hanada; Yasuhiro Akahoshi; Tetsuo Yasaka; Shoji Harada

2005-01-01

144

Development of the Explosion Breakup Model for Space Debris  

Microsoft Academic Search

This paper will examine the applicability of the National Aeronautics and Space Administration (NASA) standard breakup model 2000 revision to explosion breakup in space. The cylinder specimens of stainless steel with smooth were explosively expanded to fragmentation. The driver was a column of the high explosive PETN inserted into the central bore and initiated by exploding a bundle of fine

Hidehiro Hata; Tetsuyuki Hiroe; Kazuhito Fujiwara

2009-01-01

145

Deuteron-induced fusion in various environments  

SciTech Connect

The theory of deuteron-induced fusion will be discussed, first in free space, then in muonic molecules where the Coulomb repulsion is highly screened. It will be shown how a consistent description of the d + t reactions can be obtained in these environments using R-matrix theory. We compare fusion rates obtained from the time-dependent scattering theory with those implied by the partial widths of the resonance associated with muon-catalyzed d-t fusion. Finally, some speculative comments are made about how the d + d reactions might proceed in other media, such as metallic lattices. The unusual properties of states associated with ``shadow`` poles might account for some of the strange results seen in cold fusion experiments. We emphasize that the same methods can, and should, be used to describe this situation as well as the other two well-established phenomena.

Hale, G.M.; Talley, T.L.

1994-04-01

146

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

147

New Candidates for Recent Asteroid Breakups  

NASA Astrophysics Data System (ADS)

Asteroids in our solar system formed in a dynamically quiescent disk, but their orbits became gravitationally stirred enough by Jupiter to lead to high-speed collisions. As a result, several dozen large asteroids have been disrupted by impacts over the past several gigayears and have produced groups of fragments called asteroid families. Here we report three new candidates for asteroid families that were formed by collisions occurring in the last 1 Myr. According to our modeling of the past orbital histories of known cluster members, we estimate that the Emilkowalski, 1992 YC2, and Lucascavin clusters are 220+/-30, 50-250, and 300-800 kyr old, respectively. Together with the previously identified Datura cluster, estimated to be 450+/-50 kyr old, they are the most recent asteroid breakups ever discovered in the main belt. Astronomical observations of identified family members can be used to better understand impact physics, asteroid composition, and surface-aging processes. Discovered breakups may also be important sources of interplanetary dust.

Nesvorný, D.; Vokrouhlický, D.

2006-11-01

148

Polymeric filament thinning and breakup in microchannels  

NASA Astrophysics Data System (ADS)

The effects of elasticity on filament thinning and breakup are investigated in microchannel cross flow. When a viscous solution is stretched by an external immiscible fluid, a low 100ppm polymer concentration strongly affects the breakup process, compared to the Newtonian case. Qualitatively, polymeric filaments show much slower evolution, and their morphology features multiple connected drops. Measurements of filament thickness show two main temporal regimes: flow- and capillary-driven. At early times both polymeric and Newtonian fluids are flow-driven, and filament thinning is exponential. At later times, Newtonian filament thinning crosses over to a capillary-driven regime, in which the decay is algebraic. By contrast, the polymeric fluid first crosses over to a second type of flow-driven behavior, in which viscoelastic stresses inside the filament become important and the decay is again exponential. Finally, the polymeric filament becomes capillary-driven at late times with algebraic decay. We show that the exponential flow thinning behavior allows a measurement of the extensional viscosities of both Newtonian and polymeric fluids.

Arratia, P. E.; Gollub, J. P.; Durian, D. J.

2008-03-01

149

Polymeric filament thinning and breakup in microchannels.  

PubMed

The effects of elasticity on filament thinning and breakup are investigated in microchannel cross flow. When a viscous solution is stretched by an external immiscible fluid, a low 100 ppm polymer concentration strongly affects the breakup process, compared to the Newtonian case. Qualitatively, polymeric filaments show much slower evolution, and their morphology features multiple connected drops. Measurements of filament thickness show two main temporal regimes: flow- and capillary-driven. At early times both polymeric and Newtonian fluids are flow-driven, and filament thinning is exponential. At later times, Newtonian filament thinning crosses over to a capillary-driven regime, in which the decay is algebraic. By contrast, the polymeric fluid first crosses over to a second type of flow-driven behavior, in which viscoelastic stresses inside the filament become important and the decay is again exponential. Finally, the polymeric filament becomes capillary-driven at late times with algebraic decay. We show that the exponential flow thinning behavior allows a measurement of the extensional viscosities of both Newtonian and polymeric fluids. PMID:18517513

Arratia, P E; Gollub, J P; Durian, D J

2008-03-01

150

Breakup of H2+ by photon impact  

NASA Astrophysics Data System (ADS)

Total and partial cross sections for breakup of the ground rovibronic state of H2+ by photon impact are calculated using the exact nonadiabatic nonrelativistic Hamiltonian without approximation. The converged results span six orders of magnitude. The breakup cross section is divided into dissociative excitation and dissociative ionization. The dissociative excitation channels are divided into contributions from principal quantum numbers 1-4. For dissociative ionization, the fully differential cross section is calculated using a formally exact expression. These results are compared with approximate expressions. The Born-Oppenheimer expression for the dissociative ionization amplitude is shown to be deficient near onset. A Born-Oppenheimer approximation to the final state is shown to give accurate results for the sharing of kinetic energy between the electronic and the internuclear degrees of freedom—the doubly differential cross section. To accurately calculate the triply differential cross section, including the angular behavior, it is shown that nonadiabatic wave functions for both initial and final states are required at low electron energies.

Haxton, Daniel J.

2013-07-01

151

Study of the Breakup Reaction 8B> 7Be + p: Absorption Effects and E2 Strength  

Microsoft Academic Search

Distributions of parallel and transverse momenta for 7Be fragments formed in the breakup of 8B have been measured at 41A MeV. The p|| distributions are narrow ( 81+\\/-4 and 62+\\/-3 MeV\\/c FWHM for Be and Au targets, respectively), comparable to those of neutron halo nuclei. Reaction mechanisms influence the 7Be momentum distributions, so they do not directly reflect the valence

J. H. Kelley; Sam M. Austin; A. Azhari; D. Bazin; J. A. Brown; H. Esbensen; M. Fauerbach; M. Hellström; S. E. Hirzebruch; R. A. Kryger; D. J. Morrissey; R. Pfaff; C. F. Powell; E. Ramakrishnan; B. M. Sherrill; M. Steiner; T. Suomijärvi; M. Thoennessen

1996-01-01

152

A vector and tensor polarimeter for high-energy deuterons  

NASA Astrophysics Data System (ADS)

The characteristics of a polarimeter to measure the tensor polarization of deuterons with energy of a few GeV have been studied by Monte Carlo simulations. The analyzing reaction is forward elastic dp scattering. The results of the simulation have been verified with a prototype hydrogen cell and a recoil proton detector using drift tubes inserted in the polarimeter POMME. The test used a vector and tensor polarized deuteron beam of 1.6 GeV kinetic energy at the accelerator Saturne. The feasability of a vector and tensor deuteron high-energy polarimeter based on deuteron-proton elastic scattering reaction has been studied. We present here the prediction of a Monte Carlo simulation and the first results of a test made with a prototype, at the Saturne National Laboratory.

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

1999-01-01

153

Polarization Observables in Deuteron Photo- and Electro-Disintegration.  

National Technical Information Service (NTIS)

A comprehensive relativistic treatment of polarization observables in deuteron photo- and electro-disintegration is presented from a unified standpoint. A discussion of necessary and sufficient measurements needed for a complete determination of all trans...

V. Dmitrasinovic F. Gross

1989-01-01

154

Relativistic deuteron structure function at large Q2  

NASA Astrophysics Data System (ADS)

The deuteron deep inelastic unpolarized structure function F2D is described using the Wilson operator product expansion method. In the leading twist approximation the convolution model is restored and an explicit formula for the nucleon distribution function in the deuteron is presented, accounting for binding effects in a covariant way. The long distance behavior, related to the deuteron bound state properties, is evaluated using the Bethe-Salpeter equation with one nucleon on-mass-shell. The calculation of the ratio FD2/2FN2 is compared with other convolution models showing important deviations in the region of large x. In part, this deviation can be attributed to deuteron model dependencies.

Pinto, J. P.; Amorim, A.; Santos, F. D.

1999-09-01

155

Magnetic spectrometry of deuteron spectra in NX2 plasma focus  

Microsoft Academic Search

Summary form only given. Magnetic spectrometry using polymer nuclear track detectors is used for high-resolution measurement of the energy spectrum of deuterons (> 250 keV) emitted from the pinch-column of the NX2 plasma focus (PF). The spectrum is measured for single PF shots. A 25 mum pinhole images the deuteron source on the spectrometer. This pinhole enables differential vacuum to

M. V. Roshan; A. R. Talebitaher; R. S. Rawat; P. Lee; S. V. Springham

2009-01-01

156

Gamma-Deuteron Compton Scattering in Effective Field Theory  

SciTech Connect

The differential cross section for {gamma}-deuteron Compton scattering is computed to next-to-leading order (NLO) in an effective field theory that describes nucleon-nucleon interactions below the pion production threshold. Contributions at NLO include the nucleon isoscalar electric polarizability from its 1/m{sub {pi}} behavior in the chiral limit. The parameter free prediction of the {gamma}-deuteron differential cross section at NLO is in good agreement with data.

Jiunn-Wei Chen; Harald W. Griesshammer; Martin J. Savage; Roxanne P. Springer

1998-12-01

157

Effect of the tensile strength on the stability against rotational breakup of icy bodies  

NASA Astrophysics Data System (ADS)

Focusing on primitive icy minor bodies in the solar system like cometary nuclei, centaurs, transneptunian objects (TNOs), and main-belt comets (MBCs) we investigate the stability of these objects against rotational breakup by comparing their location in (radius - rotational period) space with respect to separation lines of the stable and breakup zones in this plane. We estimate the bulk tensile strength according to new structural and elasto-mechanical models of grain-aggregates, using these tensile strengths to compute separation lines. We note that the process of grain coagulation and growth is highly uncertain in the field of solar system formation and we simply don't know how to grow interstellar grains to aggregates larger than about 1 mm but we apply in our calculations the recently available elasto-mechanical models of grain-aggregates. Accorging to this study most of the observed comets, centaurs, TNOs, and MBCs are stable against rotational breakup, with a few notable exceptions. E.g., we suggest that the rotational fission is a likely scenario for the Haumea-family in the Kuiper belt.

Toth, Imre; Lisse, Carey M.

158

The TAB method for numerical calculation of spray droplet breakup  

SciTech Connect

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

O'Rourke, P.J.; Amsden, A.A.

1987-01-01

159

Predicting color breakup on field-sequential displays  

NASA Astrophysics Data System (ADS)

The quest for color head- and helmet-mounted displays has led some designers to consider the use of field-sequential color (FSC) because it offers higher resolution than conventional color displays in a compact package. Unfortunately, FSC displays exhibit color breakup sometimes, and the viewing conditions under which this occurs have not been established very well. We performed an experiment to determine color-breakup thresholds for a simple FSC stimulus as a function of stimulus luminance, contrast, and retinal velocity. We developed equations that describe the results and can be used to predict whether color breakup will be visible for specified viewing conditions.

Post, David L.; Monnier, Patrick; Calhoun, Christopher S.

1997-06-01

160

New description of four-body break-up reaction  

SciTech Connect

We present a new method of smoothing discrete breakup cross sections calculated by the method of continuum-discretized coupled-channels. In the four-body breakup reaction of {sup 12}C({sup 6}He, nn{sup 4}He) at E{sub in} = 229.8 MeV, the continuous breakup cross section is evaluated as a function of the excitation energy of {sup 6}He. Convergence of the cross section with respect to extending the modelspace is also confirmed.

Matsumoto, T. [Meme Media Laboratory, Hokkaido University, Sapporo 060-8628 (Japan); Kato, K. [Division of Physics, Graduate School of Science, Hokkaido University, Sapporo 060-0810 (Japan); Yahiro, M. [Department of Physics, Kyushu University, Fukuoka 812-8581 (Japan)

2011-06-28

161

The TAB method for numerical calculation of spray droplet breakup  

NASA Astrophysics Data System (ADS)

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

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

162

A Requirement for Radiationless Deuteron Fusion  

NASA Astrophysics Data System (ADS)

Referring to the Fleischmann-Pons effect in the deuterium-palladium system, McKubre says: "The evidence in my view for the appearance of an anomalous unaccounted excess heat in the deuterium-palladium system is essentially overwhelming. There is something there. It's larger by more than 1 order of magnitude, in some cases by more than 2 orders of magnitude, than the sum total of all possible chemical reactions."(M. McKubre, "Anomalous Heat Production from Hydrogen Saturated Palladium", Presentation at American Chemical Society Western Regional Meeting, Ontario, CA, 8 October 1999.) The 2-electron wave function for the helium atom ground state can be written ? = ? (r) g(r_12), where ? (r) is a radial symmetric function and g(r_12) has a cusp at r_12 = 0. A requirement for radiationless fusion, consistent with non-separable nuclear/electromagnetic interactions (S.R. and T.A.Chubb, talk presented this session.), is that the 2-deuteron wave function is of the form ? = ? (r) g(r_12), where ?(r) and g(r_12) are Bloch functions, and g(r_12), on length-scales associated with atomic processes, has N_cell cusps, with N_cell > ~ 10^4.

Chubb, Talbot; Chubb, Scott

2000-03-01

163

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

PubMed

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

De Fazio, Dario

2014-05-21

164

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...

165

Coincident UVI and Wind Observations of Pseudo-Breakups  

NASA Technical Reports Server (NTRS)

Using images taken by the Ultraviolet Imager (UVI) onboard the Polar spacecraft, we identify periods of pseudo-breakup activity coincident with perigee passes of the WIND spacecraft through the magnetotail. Previous studies have shown that from both observations on the ground and in the magnetotail there is very little difference phenomenologically between substorm onset and pseudo-breakups except for the degree of localization and the absence of global expansion. This raises the question of what prevents a pseudo-breakup from expanding globally. For the time intervals studied, we find a high correlation between pseudo-breakups and short-lived particle flux enhancements in the magnetotail. The velocity distribution of the plasma during some of these flux enhancements are indicative of bursty bulk flows.

Fillingim, M. O.; Brittnacher, M.; Parks, G. K.; Germany, G. A.; Spann, J. F.; Lin, R. P.

1998-01-01

166

New description of the four-body breakup reaction  

SciTech Connect

We present a novel method of smoothing discrete breakup cross sections calculated by the method of continuum-discretized coupled channels. The smoothing method based on the complex scaling method is tested with success for a {sup 58}Ni(d,pn) reaction at 80 MeV as an example of three-body breakup reactions and applied to a {sup 12}C({sup 6}He,nn {sup 4}He) reaction at 229.8 MeV as an example of four-body breakup reactions. Fast convergence of the breakup cross section with respect to extending the model space is confirmed. The method is also applied to {sup 12}C({sup 6}He,nn {sup 4}He) and {sup 208}Pb({sup 6}He,nn {sup 4}He) reactions at 240 MeV/A and compared with the experimental data.

Matsumoto, Takuma [Meme Media Laboratory, Hokkaido University, Sapporo 060-8628 (Japan); Kato, Kiyoshi [Division of Physics, Graduate School of Science, Hokkaido University, Sapporo 060-0810 (Japan); Yahiro, Masanobu [Department of Physics, Kyushu University, Fukuoka 812-8581 (Japan)

2010-11-15

167

Breakup of double emulsions in wedge-shaped microfluidic channels  

NASA Astrophysics Data System (ADS)

Double emulsion droplets can serve as drug delivery vehicles and individual compartments for chemical reactions, and such materials are relevant to new kinds of microfluidic applications. We study experimentally the dynamics and breakup of double emulsion droplets flowing through poly(dimethylsiloxane) (PDMS) channels. As water-in-oil-in-water (W/O/W) double emulsion droplets flow through such wedge-shaped channels, the breakup of the droplets is controlled by the capillary number and the droplet-to-orifice size ratio. We obtain a phase diagram of droplet breakup morphology from the experimental results, and explain the results via a combination of the capillary instability and thin film dynamics. The phase diagram is useful for predicting and controlling the breakup of the droplet. Finally, differences between results obtained in PDMS channels and capillary channels are discussed.

Li, Jiang; Chen, Haosheng; Stone, Howard A.

2010-11-01

168

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

169

Ultra-intense laser neutron generation through efficient deuteron acceleration  

NASA Astrophysics Data System (ADS)

Experiments at the HERCULES laser facility, originally reported by C. Zulick, et al in Applied Physics Letters (2013), have produced neutron beams with energies up to 16:8(+/-0:3) MeV using 7 3Li(d,n)8 4Be reactions. These efficient deuteron reactions required the selective acceleration of deuterons through the introduction of a deuterated plastic or cryogenically frozen D2O layer on the surface of a thin film target. It was shown that a optimized frozen D2O layer, formed in situ, yielded the highest efficiency deuteron acceleration with deuterons constituting over 99% of the accelerated light ions. The deuteron signal was optimized with respect to the delay between the heavy water deposition and laser pulse arrival, as well as the temperature of the target. A total conversion efficiency of laser energy to neutron energy of 1(+/-0:5) × 10-5 was obtained. The simulated neutron signal was found to be in reasonable agreement with the experimental spectra. The scattering of neutrons through shielding and target materials was investigated with MCNPX and determined to have a small effect on the observed neutron energies.

Zulick, C.; Dollar, F.; Chvykov, V.; Davis, J.; Kalinchenko, G.; Maksimchuk, A.; Petrov, G. M.; Raymond, A.; Thomas, A. G. R.; Willingale, L.; Yanovsky, V.; Krushelnick, K.

2013-05-01

170

Study of deuteron generalized parton distribution functions and its tensor structure function  

NASA Astrophysics Data System (ADS)

The generalized parton distribution functions of deuteron are studied based on a phenomenological effective Lagrangian approach. The electric, magnetic and quadrupole form factors are estimated. Moreover, the tensor structure function of the deuteron is discussed.

Dong, Yubing; Liang, Cuiying

2014-04-01

171

Spiral breakup in a new model of discrete excitable media  

NASA Astrophysics Data System (ADS)

The transition from the dangerous cardiac arrhythmia, ventricular tachycardia, to the fatal cardiac arrhythmia, ventricular fibrillation, is believed to be associated with the breakup of spiral waves of excitation into multiple reentrant waves. A new computational method for wave propagation in discrete excitable media employing coupled maps with continuous time is used to derive analytical criteria for parameter ranges in which spiral waves show a stationary rotation, wandering, and breakup into multiple spirals.

Ito, Hiroyuki; Glass, Leon

1991-02-01

172

Some features of spray breakup in effervescent atomizers  

Microsoft Academic Search

The near orifice spray breakup at low GLR (gas to liquid ratio by mass) values in an effervescent atomizer is studied experimentally\\u000a using water as a simulant and air as atomizing gas. From the visualizations, the near orifice spray structures are classified\\u000a into three modes: discrete bubble explosions, continuous bubble explosions and annular conical spray. The breakup of the spray

Hrishikesh P. GadgilB; B. N. Raghunandan

2011-01-01

173

Time-resolved simulations and experiments of liquid jet break-up  

NASA Astrophysics Data System (ADS)

High-speed, high-resolution experimental visualization of the break-up of a liquid jet by a gaseous cross-flow has recently become possible due to advances in video camera technology. These visualizations can now be contrasted to high fidelity CFD simulations which are also just becoming possible due to continuing growth of computational capabilities. Such a contrast is expected to go beyond traditional comparisons of time-averaged quantities and focuses on dynamics. For example, comparisons of the characteristic break-up frequency and of the spatial instantaneous features of the jet may serve as validation of the computational model and to yield insight into the physics of the dynamic interplay between the disturbances induced by the injection device and Kelvin-Helmholtz / Rayleigh-Taylor instabilities at the interface. A state-of-the-art second-order coupled Level Set and Volume Of Fluid method (CLSVOF) that can capture liquid-gas interface dynamics is used for the study. High-speed videos of non-turbulent liquid injection in laminar crossflow are used to validate the time- and grid-converged capability of the code to capture upwind wave structures caused by the centrifugal acceleration of the deflected liquid. The extension to increasing air crossflow is also discussed with focus on the column break-up mechanism.

Arienti, Marco; Soteriou, Marios; Sussman, Mark

2008-11-01

174

Liquid jet breakup characterization with application to melt-water mixing  

SciTech Connect

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

Ginsberg, T.

1986-01-01

175

Flow-induced aggregation and breakup of particle clusters controlled by surface nanoroughness.  

PubMed

Interactions between colloidal particles are strongly affected by the particle surface chemistry and composition of the liquid phase. Further complexity is introduced when particles are exposed to shear flow, often leading to broad variation of the final properties of formed clusters. Here we discover a new dynamical effect arising in shear-induced aggregation where repeated aggregation and breakup events cause the particle surface roughness to irreversibly increase with time, thus decreasing the bond adhesive energy and the resistance of the aggregates to breakup. This leads to a pronounced overshoot in the time evolution of the aggregate size, which can only be explained with the proposed mechanism. This is demonstrated by good agreement between time evolution of measured light-scattering data and those calculated with a population-balance model taking into account the increase in the primary particle nanoroughness caused by repeated breakup events resulting in the decrease of bond adhesive energy as a function of time. Thus, the proposed model is able to reproduce the overshoot phenomenon by taking into account the physicochemical parameters, such as pH, till now not considered in the literature. Overall, this new effect could be exploited in the future to achieve better control over the flow-induced assembly of nanoparticles. PMID:24156516

Moussa, Amgad S; Lattuada, Marco; Conchúir, Breanndán Ó; Zaccone, Alessio; Morbidelli, Massimo; Soos, Miroslav

2013-11-26

176

Determination of Deuteron Energy Distribution From Neutron Diagnostics in a Plasma-Focus Device  

Microsoft Academic Search

Fast neutrons from deuteron-deuteron fusion reactions were used for a study of fast deuterons in the PF-1000 plasma-focus device. The energy spectrum of neutrons was determined by the time-of-flight method using ten scintillation detectors positioned downstream, upstream, and side-on the experimental facility. Neutron energy-distribution functions enabled the determination of axial and radial components of energy of deuterons producing the fusion

Pavel Kubes; Jozef Kravarik; Daniel Klir; Karel Rezac; Martin Bohata; Marek Scholz; Marian Paduch; Krzysztof Tomaszewski; Irena Ivanova-Stanik; Leslaw Karpinski; Marek Jan Sadowski

2009-01-01

177

Three-nucleon force effects in the analyzing powers of the d(pol.) p breakup at 130-MeV  

SciTech Connect

A measurement of the analyzing powers for the 1H(\\vec {d},pp)n breakup reaction at 130 MeV polarized deuteron beam energy was carried out at KVI Groningen. The experimental setup covered a large fraction of the phase space. Obtained tensor analyzing powers T22 for selected kinematical configurations have been compared to theoretical predictions based on various approaches: the rigorous Faddeev calculations using the realistic nucleon--nucleon potentials with and without three nucleon force (3NF) models, predictions of the chiral perturbation theory, and coupled channel calculations with the explicit \\Delta degrees of freedom. In the presented configurations the results of all predictions are very close to one another and there are no significant 3NF influences. Not all of the data can be satisfactory reproduced by the theoretical calculations.

Avagyan, Harutyun; Stephan, E.; Kistryn, St.; Bodek, K.; Ciepal, I.; Deltuva, A.; Epelbaum, Evgeny; Gloeckle, Walter; Golak, J.; Kalantar-Nayestanaki, Nasser; Kamada, H.; Kis, M.; Klos, B.; Kozela, A.; Kuros-Zolnierczuk, J.; Mahjour-Shafiei, M.; Meissner, Ulf-G.; Micherdzinska, Anna; Nogga, Andreas; Sauer, Peter; Skibinski, R.; Sworst, R.; Witala, Henryk; Zejma, J.; Zipper, W.

2008-01-01

178

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

179

Elastic scattering of electrons by deuterons in the framework of the source theory by J. Schwinger  

Microsoft Academic Search

Cross sections of the elastic scattering of electrons from the deuterons are calculated with the concept of primitive interaction, disregarding the form factors of the deuteron. Formulas are derived for the various possibilities of the electron and deuteron polarization. Numerical results are given for 175 MeV scattering in the rest frame.

G. H. Goeritz; K. H. Passler; G. Sauer; P.-G. Zint

1973-01-01

180

Using Tensor Momentum Dependent Deuteron Potential to Extract the Asymptotic D/S Ratio  

SciTech Connect

A new value for the deuteron asymptotic D/S ratio {eta} = 0.02640{+-}0.00024 is extracted from an empirical linear {eta}-Q relation found for a class of deuteron momentum dependent potentials with tensor momentum dependent part. These potentials fit a recently published phase shift analysis and the binding energy of the deuteron.

Emad El-Deen, A. Sultan; Mustafa, Mustafa M. [Physics department, Faculty of Science, Sohag University (Egypt); Zahran, Elbadry S. [Physics department, Faculty of Science, Assiut University (Egypt)

2010-09-30

181

Effect of gas mass flux on cryogenic liquid jet breakup  

NASA Technical Reports Server (NTRS)

A scattered-light scanning instrument developed at NASA Lewis Research Center was used to measure the characteristic drop size of clouds of liquid nitrogen droplets. The instrument was calibrated with suspensions of monosized polystyrene spheres. In this investigation of the mechanism of liquid nitrogen jet disintegration in a high-velocity gas flow, the Sauter mean diameter, D32, was found to vary inversely with the nitrogen gas mass flux raised to the power 1.33. Values of D32 varied from 5 to 25 microns and the mass flux exponent of 1.33 agrees well with theory for liquid jet breakup in high-velocity gas flows. The loss of very small droplets due to the high vaporization rate of liquid nitrogen was avoided by sampling the spray very close to the atomizer, i.e., 1.3 cm downstream of the nozzle orifice. The presence of high velocity and thermal gradients in the gas phase also made sampling of the particles difficult. As a result, it was necessary to correct the measurements for background noise produced by both highly turbulent gas flows and thermally induced density gradients in the gas phase.

Ingebo, R. D.

1992-01-01

182

Analytical description of the breakup of liquid jets in air  

NASA Technical Reports Server (NTRS)

A viscous or inviscid cylindrical jet with surface tension in a vacuum tends to pinch due to the mechanism of capillary instability. Similarity solutions are constructed which describe this phenomenon as a critical time is encountered, for two physically distinct cases: inviscid jets governed by the Euler equations and highly viscous jets governed by the Stokes equations. In both cases the only assumption imposed is that at the time of pinching the jet shape has a radial length scale which is smaller than the axial length scale. For the inviscid case, we show that our solution corresponds exactly to one member of the one-parameter family of solutions obtained from slender jet theories and the shape of the jet is locally concave at breakup. For highly viscous jets our theory predicts local shapes which are monotonic increasing or decreasing indicating the formation of a mother drop connected to the jet by a thin fluid tube. This qualitative behavior is in complete agreement with both direct numerical simulations and experimental observations.

Papageorgiou, Demetrios T.

1993-01-01

183

Parity-violating effects in elastic electron deuteron scattering  

NASA Astrophysics Data System (ADS)

The general expressions for parity violation observables in elastic scattering of polarized and/or unpolarized electrons from unpolarized deuterons are given and are numerically evaluated for the kinematics of SAMPLE, PVA4 and G0 experiments. The dominant contribution from the interference of ? and Z exchange as well as the smaller contributions from strangeness ( s bar{{s}} components of the nucleon, parity odd admixtures in the deuteron wave function, anapole moments and radiative corrections are included and discussed in the context of parity-violating electron scattering experiments of present interest.

Ahmad, S.; Singh, S. K.; Arenhövel, H.

2009-05-01

184

Middle-high latitude N2O distributions related to the arctic vortex breakup  

NASA Astrophysics Data System (ADS)

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

Zhou, L. B.; Zou, H.; Gao, Y. Q.

2006-03-01

185

Phenomenological insight into the space-like proton elastic form factor using the deuteron impulse approximation  

NASA Astrophysics Data System (ADS)

The analysis of the JLab proton polarization data on the ratio ?pGEp(t)/GMp(t) in the framework of the unitary and analytic model of nucleon electromagnetic structure implicates surprising nondipole behavior of the proton electric form factor GEp(t) in the space-like region with the zero around the momentum transfer squared value t=-Q2=-13GeV2. This result differs from the unpolarized cross-section measurements giving the dipole behavior of GEp(t) by means of the Rosenbluth technique. Recent investigations demonstrate that inclusion of a two-photon mechanism could solve the problem, which plays an important role for the unpolarized cross section, but it is negligible for the polarization ratio. Here, investigating a size of a difference in a prediction of the deuteron elastic structure functions A(t),B(t) by both, the nondipole and the old dipole, behaviors of GEp(t) in space-like region through the nonrelativistic impulse approximation, we have come to the conclusion that the two-photon mechanism plays much less of a role for the unpolarized electron-deuteron elastic scattering than for the unpolarized electron-proton elastic scattering.

Adamuš?ín, C.; Bimbot, L.; Dubni?ka, S.; Dubni?ková, A. Z.; Tomasi-Gustafsson, E.

2008-08-01

186

The Deformation Mode of Continental Lithosphere Thinning Leading to Continental Breakup  

NASA Astrophysics Data System (ADS)

Continental breakup and sea-floor spreading initiation is necessarily preceded by thinning of the continental lithosphere. The mode of lithosphere deformation responsible for thinning and stretching the continental lithosphere leading to rupture of continental crust and the initiation of sea-floor spreading remains a key question in understanding continental breakup and rifted continental margin formation. We use a generalised kinematic model of continental lithosphere stretching and thinning to investigate lithosphere response to 4 deformation modes: depth-uniform pure-shear, two-layer decoupled pure-shear, upwelling divergent flow, and buoyancy induced upwelling. The deformation model advects lithosphere and asthenosphere material and temperature in response to these deformation modes, and the isostatic response to crustal thinning and thermal perturbations are used to predict the resulting margin geometry and bathymetry. Horizontal tensile plate forces provide the driving force for lithosphere extension. We apply this generalised lithosphere deformation model to the formation of magma poor margins. The dominant deformation mechanism of the topmost cool brittle 10-15 km of the lithosphere is assumed to be by normal faulting, at all times, as observed not only in intra-continental rifting but also at slow spreading ocean ridges. Beneath the cool brittle upper lithosphere, deformation may occur by pure-shear, upwelling divergent flow driven by a horizontal plate boundary forces (c.f. ocean ridge), or upwelling (small scale convection) arising from thermal and melt buoyancy initiated by pure-shear lithosphere stretching. We compare the predictions of different modes of lithosphere deformation, and their combinations, with observations. Mantle exhumation and apparent observations at continental margins of lithosphere and crustal thinning which exceed that predicted from observed upper crustal faulting, assuming depth-uniform (pure-shear) lithosphere stretching, both imply depth-dependent lithosphere stretching and thinning. Beneath the 10-15 km thick cool brittle topmost lithosphere, depth-dependent lithosphere thinning can be achieved by a combination of decoupled pure-shear, buoyancy induced upwelling, or upwelling divergent flow. Lithosphere thinning leading to continental breakup, sea-floor spreading initiation and rifted margin formation is most likely achieved by a simultaneous combination of pure-shear and one or more of these other deformation modes. Localised rupture of the strong topmost mantle lid immediately beneath the Moho may play an important role in localising lithosphere breakup rupture and generating depth-dependent lithosphere thinning. Final rupture of continental crust at breakup may be controlled by very large normal faults, with tens of km of heave within the cool 10-15 km thick topmost lithosphere, giving rise to broad regions of sub-horizontal exhumed footwall of crust or mantle.

Kusznir, N. J.; Manatschal, G.

2009-12-01

187

Two parallel breakup arcs around substorm expansion phase onset  

NASA Astrophysics Data System (ADS)

Substorms are the fundamental process of solar wind energy storage and explosive release in Earth's magnetotail. Recent observations have shown that the mid-tail reconnection is closely associated with auroral breakup and substorm onset. Based on the Time History of Events and Macroscale Interactions during Substorms (THEMIS) two-point measurements in the near-Earth tail with the concurrent observations of ground all-sky-camera, we showed that two parallel breakup arcs occurred around substorm expansion phase onset: one slowly propagated equatorward, another propagated poleward. The equatorward breakup arc died away soon, which may be associated with the earthward dipolarization. The poleward breakup arc continued to intensify and propagate westward during the poleward expansion, which corresponded to the tailward motion of dipolarization. It was noted that there were two corresponding substorm current wedges at different space regions when two parallel breakup arcs were observed around the substorm onset. These suggest that the dipolarization propagated earthward and tailward at the initial dipolarization onset location during the auroral expansion. These results are important for understanding substorm onset, which can provide a constraint for substorm expansion onset model.

Tang, C.

2012-12-01

188

Transparent nuclei and deuteron-gold collisions at relativistic energies  

Microsoft Academic Search

The current normalization of the cross section of inclusive high- pT particle production in deuteron-gold collisions measured at RHIC relies on Glauber model calculations for the inelastic d -Au cross section. These calculations should be corrected for diffraction. Moreover, they miss Gribov's inelastic shadowing which makes nuclei more transparent (color transparency) and reduces the inelastic cross section. The magnitude of

B. Z. Kopeliovich

2003-01-01

189

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

190

Pinning Forces in Deuteron-Irradiated A15-Superconductors.  

National Technical Information Service (NTIS)

It is shown that in monofilament samples of varying Nb sub 3 Sn-layer thickness and different reaction temperatures irradiated by 50-MeV deuterons at low temperatures the observed changes in critical current density, j(c), may be separated as caused by de...

P. Maier

1979-01-01

191

Proton-Deuteron Elastic Scattering at High Momentum Transfers.  

National Technical Information Service (NTIS)

An experimental and theoretical investigation of proton-deuteron elastic scattering at high momentum transfers is presented. The differential cross sections for backward elastic scattering at incident proton kinetic energies of 1.0, 1.3, and 1.5 GeV were ...

E. Coleman

1966-01-01

192

Photodissociation of the Deuteron from 150 to 450 Mev  

Microsoft Academic Search

The photodissociation of the deuteron has been investigated for laboratory photon energies of 150, 200, 250, 300, 350, 400, and 450 Mev at laboratory angles of 39, 56, 74, 93, 115, and 138 degrees. The process was identified by detecting the recoil protons in a range-ionization telescope. The total cross section has a relative minimum at 150 Mev followed by

J. C. Keck; A. V. Tollestrup

1956-01-01

193

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

194

TOPICAL REVIEW: Solving the three-body Coulomb breakup problem using exterior complex scaling  

NASA Astrophysics Data System (ADS)

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

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

2004-09-01

195

On the breakup of tectonic plates by polar wandering  

NASA Technical Reports Server (NTRS)

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

Liu, H.-S.

1974-01-01

196

Modeling suggests that oblique extension facilitates rifting and continental break-up  

NASA Astrophysics Data System (ADS)

In many cases the initial stage of continental break-up was and is associated with oblique rifting. That includes break-up in the Southern and Equatorial Atlantic, separation from eastern and western Gondwana as well as many recent rift systems, like Gulf of California, Ethiopia Rift and Dead Sea fault. Using a simple analytic mechanical model and advanced numerical, thermomechanical modeling techniques we investigate the influence of oblique extension on the required tectonic force in a three-dimensional setting. While magmatic processes have been already suggested to affect rift evolution, we show that additional mechanisms emerge due to the three-dimensionality of an extensional system. Focusing on non-magmatic rift settings, we find that oblique extension significantly facilitates the rift process. This is due to the fact that oblique deformation requires less force in order to reach the plastic yield limit than rift-perpendicular extension. The model shows that in the case of two competing non-magmatic rifts, with one perpendicular and one oblique to the direction of extension but otherwise having identical properties, the oblique rift zone is mechanically preferred and thus attracts more strain.

Brune, Sascha; Popov, Anton A.; Sobolev, Stephan V.

197

Scaling for deuteron structure functions in a relativistic light-front model  

NASA Astrophysics Data System (ADS)

Scaling limits of the structure functions [B.D. Keister,

Phys. Rev. C 37, 1765 (1988)
], W1 and W2, are studied in a relativistic model of the two-nucleon system. The relativistic model is defined by a unitary representation, U(?,a), of the Poincaré group which acts on the Hilbert space of two spinless nucleons. The representation is in Dirac's [P.A.M. Dirac,
Rev. Mod. Phys. 21, 392 (1949)
] light-front formulation of relativistic quantum mechanics and is designed to give the experimental deuteron mass and n-p scattering length. A model hadronic current operator that is conserved and covariant with respect to this representation is used to define the structure tensor. This work is the first step in a relativistic extension of the results of Hueber, Glöckle, and Boemelburg [D. Hueber et al.
Phys. Rev. C 42, 2342 (1990)
]. The nonrelativistic limit of the model is shown to be consistent with the nonrelativistic model of Hueber, Glöckle, and Boemelburg. The relativistic and nonrelativistic scaling limits, for both Bjorken and y scaling are compared. The interpretation of y scaling in the relativistic model is studied critically. The standard interpretation of y scaling requires a soft wave function which is not realized in this model. The scaling limits in both the relativistic and nonrelativistic case are related to probability distributions associated with the target deuteron.

Polyzou, W. N.; Glöckle, W.

1996-06-01

198

New capabilities for Monte Carlo simulation of deuteron transport and secondary products generation  

NASA Astrophysics Data System (ADS)

Several important research programs are dedicated to the development of facilities based on deuteron accelerators. In designing these facilities, the definition of a validated computational approach able to simulate deuteron transport and evaluate deuteron interactions and production of secondary particles with acceptable precision is a very important issue. Current Monte Carlo codes, such as MCNPX or PHITS, when applied for deuteron transport calculations use built-in semi-analytical models to describe deuteron interactions. These models are found unreliable in predicting neutron and photon generated by low energy deuterons, typically present in those facilities. We present a new computational tool, resulting from an extension of the MCNPX code, which improve significantly the treatment of problems where any secondary product (neutrons, photons, tritons, etc.) generated by low energy deuterons reactions could play a major role. Firstly, it handles deuteron evaluated data libraries, which allow describing better low deuteron energy interactions. Secondly, it includes a reduction variance technique for production of secondary particles by charged particle-induced nuclear interactions, which allow reducing drastically the computing time needed in transport and nuclear response calculations. Verification of the computational tool is successfully achieved. This tool can be very helpful in addressing design issues such as selection of the dedicated neutron production target and accelerator radioprotection analysis. It can be also helpful to test the deuteron cross-sections under development in the frame of different international nuclear data programs.

Sauvan, P.; Sanz, J.; Ogando, F.

2010-03-01

199

Breakup of an oxygen nucleus to light fragments of mass number in the range A Less-Than-Or-Slanted-Equal-To 4 in {sup 16}Op interactions at a momentum of 3.25 GeV/c per nucleon  

SciTech Connect

New experimental data on the correlations of the yields of {sup 4}He and {sup 2}H nuclei in semi-inclusive reactions involving by the production of {sup 3}He and {sup 3}H mirror nuclei in {sup 16}Op collisions at a momentum of 3.25 GeV/c per nucleon are presented. The mean multiplicities of protons and neutrons appearing as fragments are found to be independent of the number of associated deuterons, this indicating that a considerable part of these fragments originate from the breakup of the alpha-particle clusters forming the oxygen nucleus.

Olimov, K., E-mail: olimov@uzsci.net [Uzbek Academy of Sciences, Institute for Physics and Technology, Fizika-Solntse Research and Production Association (Uzbekistan); Glagolev, V. V. [Joint Institute for Nuclear Research (Russian Federation); Gulamov, K. G.; Kurbanov, A.; Lutpullaev, S. L.; Olimov, A. K.; Petrov, V. I.; Yuldashev, A. A. [Uzbek Academy of Sciences, Institute for Physics and Technology, Fizika-Solntse Research and Production Association (Uzbekistan)

2012-04-15

200

Deuteron scattering on {sup 6}Li at an energy of 25 MeV  

SciTech Connect

At an energy of 25 MeV and in the angular range 7{sup o}-175{sup o} in the laboratory frame, angular distributions were measured for elastic deuteron scattering on {sup 6}Li nuclei and for the respective inelastic-scattering processes accompanied by the transitions to the ground state (1+) of the {sup 6}Li nucleus and to its excited state at E{sub x} = 2.186 MeV (J{sup {pi}} = 3{sup +}). The resulting data were analyzed on the basis of the optical model of the nucleus and the coupled-reaction-channel method with allowance for the mechanism of alpha-particle-cluster exchange. It is shown that only upon including, in the analysis, channel coupling and the exchange mechanism can the experimental cross sections for elastic and inelastic scattering be reproduced over the entire range of angles.

Burtebayev, N. [National Nuclear Center of the Republic of Kazakhstan, Institute of Nuclear Physics (Kazakhstan); Artemov, S. V. [Uzbek Academy of Sciences, Institute of Nuclear Physics (Uzbekistan); Duisebayev, B. A.; Kerimkulov, Zh. K. [National Nuclear Center of the Republic of Kazakhstan, Institute of Nuclear Physics (Kazakhstan); Kuranov, S. B. [Uzbek Academy of Sciences, Institute of Nuclear Physics (Uzbekistan); Sakuta, S. B., E-mail: sakuta@dni.polyn.kiae.s [Russian Research Center Kurchatov Institute (Russian Federation)

2010-05-15

201

On the correlation between the deuteron quadrupole moment, the deuteron asymptotic D/S ratio, and the S-wave normalization constant  

SciTech Connect

The correlation between the deuteron quadrupole moment Q, the deuteron asymptotic D/S ratio {eta}, and the deuteron asymptotic normalization constant AS is studied. For local nucleon-nucleon potentials, it was found that the quantities Q/{eta} and A{sub S}{sup 2} are related by a linear equation. Owing to this, the deuteron quadrupole moment Q can be determined from known values of AS and {eta} with an absolute precision of about 0.0003 fm{sup 2}. The inclusion of the correction for meson-exchange currents and the use of the experimental neutron-proton phase shifts from the GWU partial-wave analysis made it possible to estimate the deuteron quadrupole moment at Q = 0.2852 fm{sup 2}, which is in good agreement with experimental data.

Babenko, V. A., E-mail: pet2@ukr.net; Petrov, N. M. [National Academy of Sciences of Ukraine, Bogolyubov Institute for Theoretical Physics (Ukraine)

2011-03-15

202

Beam-breakup instability theory for energy recovery linacs  

Microsoft Academic Search

Here we will derive the general theory of the beam-breakup instability in recirculating linear accelerators, in which the bunches do not have to be at the same rf phase during each recirculation turn. This is important for the description of energy recovery linacs where bunches are recirculated at a decelerating phase of the rf wave and for other recirculator arrangements

Georg H. Hoffstaetter; Ivan V. Bazarov

2004-01-01

203

Modeling droplet breakup processes under micro-explosion conditions  

Microsoft Academic Search

This paper presents a numerical model of micro-explosion for multicomponent droplets. The first part of the model addresses the mass and temperature distribution inside the droplet and the bubble growth within the droplet. The bubble generation is described by a homogeneous nucleation theory, and the subsequent bubble growth leads to the final explosion (i.e., breakup). The second part of the

Yangbing Zeng; Chia-fon F. Lee

2007-01-01

204

Hot spot activity and the break-up of Pangea  

Microsoft Academic Search

The Mesozoic and Cenozoic positions of the continents that formed Pangea in the Triassic–Jurassic were derived from paleomagnetic and intraplate volcanic data, paleoclimatic observations, such as reef and fossil flora distribution, and geological observations. Major hot spots helped to determine the longitudinal position of Pangea and to construct a model of plate motion during the Pangean break-up. The position of

Jan Golonka; Natalia Yurevna Bocharova

2000-01-01

205

Breakup of New Orleans Households after Hurricane Katrina  

ERIC Educational Resources Information Center

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

Rendall, Michael S.

2011-01-01

206

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

207

The cometary breakup hypothesis re-examined - A reply  

NASA Astrophysics Data System (ADS)

It is shown that the giant comet breakup hypothesis has a clear basis in astronomical fact and, contrary to LaViolette's claims, is consistent with the available geochemical evidence. The importance of further trace element studies in polar ice for testing this hypothesis is, however, emphasized.

Clube, S. V. M.; Napier, W. M.

1987-04-01

208

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

209

Precise Measurement of Deuteron Tensor Analyzing Powers with BLAST  

SciTech Connect

We report a precision measurement of the deuteron tensor analyzing powers T{sub 20} and T{sub 21} at the MIT-Bates Linear Accelerator Center. Data were collected simultaneously over a momentum transfer range Q=2.15-4.50 fm{sup -1} with the Bates Large Acceptance Spectrometer Toroid using a highly polarized deuterium internal gas target. The data are in excellent agreement with calculations in a framework of effective field theory. The deuteron charge monopole and quadrupole form factors G{sub C} and G{sub Q} were separated with improved precision, and the location of the first node of G{sub C} was confirmed at Q=4.19{+-}0.05 fm{sup -1}. The new data provide a strong constraint on theoretical models in a momentum transfer range covering the minimum of T{sub 20} and the first node of G{sub C}.

Zhang, C.; Akdogan, T.; Bertozzi, W.; Botto, T.; Clasie, B.; DeGrush, A.; Dow, K.; Farkhondeh, M.; Franklin, W.; Gilad, S.; Hasell, D.; Kolster, H.; Maschinot, A.; Matthews, J.; Meitanis, N.; Milner, R.; Redwine, R.; Seely, J.; Shinozaki, A.; Tschalaer, C. [Laboratory for Nuclear Science and Bates Linear Accelerator Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

2011-12-16

210

Neutron structure effects in the deuteron and one neutron halos  

SciTech Connect

Although the neutron (n) does not carry a total electric charge, its charge and magnetization distributions represented in momentum space by the electromagnetic form factors, F{sub 1}{sup (n)}(q{sup 2}) and F{sub 2}{sup (n)}(q{sup 2}), lead to an electromagnetic potential of the neutron. Using this fact, we calculate the electromagnetic corrections to the binding energy, B{sub d}, of the deuteron and a one-neutron halo nucleus ({sup 11}Be) by evaluating the neutron-proton and the neutron-charged core ({sup 10}Be) potential, respectively. The correction to B{sub d} ({approx}9 keV) is comparable to that arising due to the inclusion of the {delta}-isobar component in the deuteron wave function. In the case of the more loosely bound halo nucleus, {sup 11}Be, the correction is close to about 2 keV.

Nowakowski, M.; Kelkar, N. G. [Departamento de Fisica, Universidad de los Andes, Cra.1 No.18A-10, Santafe de Bogota (Colombia); Mart, T. [Departemen Fisika, FMIPA, Universitas Indonesia, Depok 16424 (Indonesia)

2006-08-15

211

Deuteron NMR in Formic and Acetic Acid Single Crystals  

Microsoft Academic Search

The deuteron quadrupole coupling constants and asymmetry factors in single crystals of DCOOH and HCOOD are found to be 161± 2 kHz, &eegr;=0.040± 0.025 and 165.1± 2.7 kHz, &eegr;=0.125± 0.030, respectively. These are compared with free molecule and single crystal results of others on the formate group. In addition, attention is called to influence of the X-fragment electronegativity upon the

Guy J. Adriaenssens; John L. Bjorkstam

1972-01-01

212

Transparent Nuclei and Deuteron-Gold Collisions at RHIC  

Microsoft Academic Search

The current normalization of the cross section of inclusive high-pT particle\\u000aproduction in deuteron-gold collisions measured RHIC relies on Glauber\\u000acalculations for the inelastic d-Au cross section. These calculations should be\\u000acorrected for diffraction. Moreover, they miss the Gribov's inelastic shadowing\\u000awhich makes nuclei more transparent (color transparency). The magnitude of this\\u000aeffect rises with energy and it may dramatically

B. Z. Kopeliovich

2003-01-01

213

Inelastic Electron-Deuteron Scattering Cross Sections at High Energies  

Microsoft Academic Search

The effects on the cross sections for the inelastic electron-deuteron scattering process e+d-->e+n+p of interactions between the outgoing nucleons are examined in detail. The cross sections are calculated in the first Born approximation with respect to the electromagnetic interaction using nucleon wave functions modified by the final state interactions. Crude estimates indicate that the peak value of the cross section

Loyal Durand

1959-01-01

214

STUDY OF 83NEUTRON NUCLEI BY DEUTERON STRIPPING REACTIONS  

Microsoft Academic Search

A study of the 83-neutron nuclei Ba¹³⁸, La¹³⁹, and Pr\\/sup ; 141\\/ was made by the (d,p) stripping reaction with 11-Mev deuterons. The ; outgoing protons were analyzed with a magnetic Spectrometer, and angular ; distributions were measured for the well-resolved states, Excited levels, with ; spins and parities indicated in parentheses, were found at 0 (7\\/2-), in Ba\\/sup ;

F. W. Bingham; M. B. Sampson

1962-01-01

215

Study of 83Neutron Nuclei by Deuteron Stripping Reactions  

Microsoft Academic Search

A study of the 83-neutron nuclei Ba138, La139, and Pr141 was made by the (d, p) stripping reaction with 11-MeV deuterons. The outgoing protons were analyzed with a magnetic spectrometer, and angular distributions were measured for the well-resolved states. Excited levels, with spins and parities indicated in parentheses, were found at 0 (72-), 0.59 (32-), 1.07, 1.39, 1.67 (52-), 1.20

F. W. Bingham; M. B. Sampson

1962-01-01

216

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

217

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

218

Deuteron Magnetic Resonance of Ferroelectric Potassium Ferrocyanide Trihydrate  

Microsoft Academic Search

The quadrupolar splittings and linewidths of the deuteron magnetic resonance of single crystals of ferroelectric K4Fe(CN)6·3D2O(KFCT) have been measured from ?100° to 58°C. At low temperatures eight pairs of resonance lines are observed corresponding to four types of water molecules A, B, C, D, and their ac plane enantiomorphs A+, B+, C+, D+. The molecules are undergoing a fast 180°

Tung Tsang; D. E. O'Reilly

1965-01-01

219

Theoretical study of incoherent ? photoproduction on a deuteron target  

NASA Astrophysics Data System (ADS)

We study the photoproduction of ? mesons in deuteron, paying attention to the modification of the cross-section from bound protons to the free ones. For this purpose we take into account Fermi motion in single scattering and rescattering of ? to account for ? absorption on a second nucleon as well as the rescattering of the proton on the neutron. We find that the contribution of the double scattering for ? is much smaller than the typical cross-section of ? p ? ? p in free space, which implies a very small screening of the ? production in deuteron. The contribution from the proton rescattering, on the other hand, is found to be not negligible compared to the cross-section of ? p ? ? p in free space, and leads to a moderate reduction of the ? photoproduction cross-section on a deuteron at forward angles if the LEPS set-up is taken into account. The Fermi motion allows contribution of the single scattering in regions forbidden by phase-space in the free case. In particular, we find that for momentum transfer squared close to the maximum value, the Fermi motion changes drastically the shape of d?/d t, to the point that the ratio of this cross-section to the free one becomes very sensitive to the precise value of t chosen, or the size of the bin used in an experimental analysis. Hence, this particular region of t does not seem to be the most indicated to find effects of a possible ? absorption in the deuteron. This reaction is studied theoretically as a function of t and the results are contrasted with recent experiments at LEPS and Jefferson Lab. The effect of the experimental angular cuts at LEPS is also discussed, providing guidelines for future experimental analyses of the reaction.

Sekihara, T.; Martínez Torres, A.; Jido, D.; Oset, E.

2012-01-01

220

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

221

Covariant spectator theory of np scattering: Deuteron magnetic moment  

NASA Astrophysics Data System (ADS)

The deuteron magnetic moment is calculated using two model wave functions obtained from 2007 high-precision fits to np scattering data. Included in the calculation are a new class of isoscalar np interaction currents, which are automatically generated by the nuclear force model used in these fits. After normalizing the wave functions, nearly identical predictions are obtained: model WJC-1, with larger relativistic P-state components, gives 0.863(2), while model WJC-2 with very small P-state components gives 0.864(2). These are about 1% larger than the measured value of the moment, 0.857 n.m., giving a new CST prediction for the size of the ??? exchange, and other purely transverse interaction currents that are largely unconstrained by the nuclear dynamics. The physical significance of these results is discussed, and general formulas for the deuteron form factors, expressed in terms of deuteron wave functions and a new class of interaction current wave functions, are given.

Gross, Franz

2014-06-01

222

Measurement of Tensor Polarization in Elastic Electron-Deuteron Scattering at Large Momentum Transfer  

Microsoft Academic Search

Tensor polarization observables ( t20, t21, and t22) have been measured in elastic electron-deuteron scattering for six values of momentum transfer between 0.66 and 1.7 \\\\(GeV\\/c\\\\)2. The experiment was performed at the Jefferson Laboratory in Hall C using the electron High Momentum Spectrometer, a specially designed deuteron magnetic channel and the recoil deuteron polarimeter POLDER. The new data determine to

David Abbott; Abdellah Ahmidouch; Heinz Anklin; J. Arvieux; Jacques Ball; S. Beedoe; Elizabeth Beise; Louis Bimbot; Werner Boeglin; Herbert Breuer; P. Brindza; R. Carlini; N. S. Chant; S. Danagoulian; K. Dow; J.-E. Ducret; J. Dunne; L. Ewell; L. Eyraud; C. Furget; M. Garçon; R. Gilman; C. Glashausser; P. Gueye; K. Gustafsson; K. Hafidi; A. Honegger; J. Jourdan; S. Kox; G. Kumbartzki; L. Lu; A. Lung; D. Mack; P. Markowitz; J. McIntyre; D. Meekins; F. Merchez; J. Mitchell; R. Mohring; S. Mtingwa; H. Mrktchyan; D. Pitz; L. Qin; R. D. Ransome; J.-S. Réal; P. G. Roos; P. Rutt; R. Sawafta; S. Stepanyan; R. Tieulent; E. Tomasi-Gustafsson; W. Turchinetz; K. Vansyoc; J. Volmer; E. Voutier; W. Vulcan; C. Williamson; S. A. Wood; C. Yan; J. Zhao; W. Zhao

2000-01-01

223

Precise Measurement of the Deuteron Elastic Structure Function A\\\\(Q2\\\\)  

Microsoft Academic Search

The A\\\\(Q2\\\\) structure function in elastic electron-deuteron scattering was measured at six momentum transfers Q2 between 0.66 and 1.80 \\\\(GeV\\/c\\\\)2 in Hall C at Jefferson Laboratory. The scattered electrons and recoil deuterons were detected in coincidence, at a fixed deuteron angle of 60.5°. These new precise measurements resolve discrepancies between older sets of data. They put significant constraints on existing

D. Abbott; A. Ahmidouch; H. Anklin; J. Arvieux; J. Ball; S. Beedoe; E. J. Beise; L. Bimbot; W. Boeglin; H. Breuer; R. Carlini; N. S. Chant; S. Danagoulian; K. Dow; J.-E. Ducret; J. Dunne; R. Ent; L. Ewell; L. Eyraud; C. Furget; M. Garçon; R. Gilman; C. Glashausser; P. Gueye; K. Gustafsson; K. Hafidi; A. Honegger; J. Jourdan; S. Kox; G. Kumbartzki; L. Lu; A. Lung; D. Mack; P. Markowitz; J. McIntyre; D. Meekins; F. Merchez; J. Mitchell; R. Mohring; S. Mtingwa; H. Mrktchyan; D. Pitz; L. Qin; R. Ransome; J.-S. Réal; P. G. Roos; P. Rutt; R. Sawafta; S. Stepanyan; R. Tieulent; E. Tomasi-Gustafsson; W. Turchinetz; K. Vansyoc; J. Volmer; E. Voutier; W. Vulcan; C. Williamson; S. A. Wood; C. Yan; J. Zhao; W. Zhao; J. Ball

1999-01-01

224

Tensor Polarization Measurement in Elastic Electron--Deuteron Scattering at Large Momentum Transfer  

Microsoft Academic Search

The three tensor polarization components (t20, t21 and t22) of the recoil deuteron in elastic electron-deuteron scattering have been measured in the range of 4-momentum transfer Q = 4.1-6.8 fm-1. The experiment was performed with the multi-GeV, high intensity electron beam available at the Jefferson Laboratory and using the tensor deuteron polarimeter POLDER. These new data are used to separate

C. Furget; D. Abbott; A. Ahmidouch; H. Anklin; J. Arvieux; J. Ball; S. Beedoe; E. J. Beise; L. Bimbot; W. Boeglin; H. Breuer; R. Carlini; N. S. Chant; S. Danagoulian; K. Dow; J. E. Ducret; J. Dunne; L. Ewell; L. Eyraud; M. Garcon; R. Gilman; C. Glashausser; P. Gueye; K. Gustafsson; K. Hafidi; A. Honneger; J. Jourdan; S. Kox; G. Kumbarski; L. Lu; A. Lung; D. Mack; P. Markowitz; J. McIntyre; D. Meekins; F. Merchez; J. Mitchell; S. Mtingwa; H. Mrktchyan; D. Pitz; L. Qin; R. Ransome; J. S. Real; P. G. Roos; P. Rutt; W. Schmidt; R. Sawafta; S. Stepanyan; E. J. Stephenson; R. Tieulent; E. Tomasi-Gustafsson; W. Turchinetz; K. Vansyoc; J. Volmer; E. Voutier; W. Vulcan; C. Williamson; S. A. Wood; C. Yan; J. Zhao; W. Zhao

1998-01-01

225

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

Microsoft Academic Search

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.

Sachie Kimura; Aldo Bonasera

2011-01-01

226

Role of the K 1 Meson in K 0 Photoproduction off the Deuteron  

NASA Astrophysics Data System (ADS)

Neutral kaon photoproduction off the nucleon and deuteron has been reinvestigated by utilizing the new experimental data on both targets. An isobar model for elementary operator and impulse approximation for the reaction on the deuteron have been used. The available free parameters in the elementary model have been extracted from both elementary and deuteron data. In contrast to the elementary reaction, fitting the deuteron data requires an inclusion of weighting factor. The result indicates that the angular distribution of the elementary {K^0?} process does not show backward peaking behavior.

Salam, A.; Mart, T.; Miyagawa, K.

2013-03-01

227

Spallation of 197Au with 4.4-GeV deuterons  

NASA Astrophysics Data System (ADS)

A comprehensive set of 110 radioactive nuclide cross sections with mass numbers 22 ? A ? 198 amu in the interaction of 4.4-GeV deuterons with 197Au have been measured for the first time. The results including charge distributions have been parameterized in term of a 3-parameter equation in order to reproduces the isobaric distributions. Using data from the charge distributions, the total mass-yield distribution was obtained. The new experimental data of the recoil properties of reaction products were also obtained. Kinematical characteristics of the reaction products obtained from measurements of the residuals emitted in the forward and backward directions exhibit different behavior depending on the mass region. The kinematical features of reaction products have been analyzed on the basis of the two-step model of high-energy nuclear reactions and discussed in terms of the different reaction mechanisms.

Karapetyan, G. S.; Balabekyan, A. R.; Demekhina, N. A.

2014-04-01

228

Breakup of liquid jets from non-circular orifices  

NASA Astrophysics Data System (ADS)

The purpose of this investigation is to study the effect of the orifice geometry on liquid breakup. In order to develop a better understanding of the liquid jet breakup, investigations were carried out in two steps—study of low-pressure liquid jet breakup and high-pressure fuel atomization. This paper presents the experimental investigations conducted to study the flow behavior of low-pressure water jets emanating from orifices with non-circular geometries, including rectangular, square, and triangular shapes and draws a comparison with the flow behavior of circular jets. The orifices had approximately same cross-sectional areas and were machined by electro-discharge machining process in stainless steel discs. The liquid jets were discharged in the vertical direction in atmospheric air at room temperature and pressure conditions. The analysis was carried out for gage pressures varying from 0 to 1,000 psi (absolute pressures from 0.10 to 6.99 MPa). The flow behavior was analyzed using high-speed visualization techniques. To draw a comparison between flow behavior from circular and non-circular orifices, jet breakup length and width were measured. The flow characteristics were analyzed from different directions, including looking at the flow from the straight edges of the orifices as well as their sharp corners. The non-circular geometric jets demonstrated enhanced instability as compared to the circular jets. This has been attributed to the axis-switching phenomenon exhibited by them. As a result, the non-circular jets yielded shorter breakup lengths as compared to the circular jets. In order to demonstrate the presence of axis-switching phenomenon in square and triangular jets, the jet widths were plotted along the axial direction. This technique clearly demonstrated the axis switching occurring in square and triangular jets, which was not clearly visible unlike the case of rectangular jets. To conclude, non-circular geometry induces greater instabilities in the liquid jets, thereby leading to faster disintegration. Thus, non-circular orifice geometries can provide a cheaper solution of improving liquid breakup and thus may enhance fuel atomization as compared to the precise manufacturing techniques of drilling smaller orifices or using costly elevated fuel injection pressure systems.

Sharma, Priyesh; Fang, Tiegang

2014-02-01

229

Study of particle atomization by breakup of water-drops using pulse combustion nozzle  

NASA Astrophysics Data System (ADS)

In this study, the pulse combustion is used to produce nanometer-size particle and the mechanism is clarified. The feature of jet generated by the pulse combustion chamber, whose pulse cycle is about 600 Hz, is visualized by the shadowgraph technique and is compared with that by the burner combustion. There exists very fine structure of vortices in the jet of pulse combustion. The water drop whose diameter is about 3mm is broken-up in this jet. This breakup does not occur in the jet of burner combustion. The droplets generated by the breakup are evaporated instantly and the nanometer-size particle is produced. Sound level in the jet is about 140 dB and sound power is not strong enough to promote the evaporation. Instead of sound, the very fine vortices, whose scale is of some mm, play an important role. These vortices give pressure fluctuation on the water droplet of 5000 Hz to 8000 Hz and they promote evaporation and deformation of the droplet.

Michiwaki, Akira; Tsutahara, Michihisa; Hiraishi, Masayuki; Mae, Kentaro; Kominami, Kiyokazu; Umeda, Yoshikuni; Kubotani, Atsunobu

2009-12-01

230

A 'snowball Earth' climate triggered by continental break-up through changes in runoff.  

PubMed

Geological and palaeomagnetic studies indicate that ice sheets may have reached the Equator at the end of the Proterozoic eon, 800 to 550 million years ago, leading to the suggestion of a fully ice-covered 'snowball Earth'. Climate model simulations indicate that such a snowball state for the Earth depends on anomalously low atmospheric carbon dioxide concentrations, in addition to the Sun being 6 per cent fainter than it is today. However, the mechanisms producing such low carbon dioxide concentrations remain controversial. Here we assess the effect of the palaeogeographic changes preceding the Sturtian glacial period, 750 million years ago, on the long-term evolution of atmospheric carbon dioxide levels using the coupled climate-geochemical model GEOCLIM. In our simulation, the continental break-up of Rodinia leads to an increase in runoff and hence consumption of carbon dioxide through continental weathering that decreases atmospheric carbon dioxide concentrations by 1,320 p.p.m. This indicates that tectonic changes could have triggered a progressive transition from a 'greenhouse' to an 'icehouse' climate during the Neoproterozoic era. When we combine these results with the concomitant weathering effect of the voluminous basaltic traps erupted throughout the break-up of Rodinia, our simulation results in a snowball glaciation. PMID:15029192

Donnadieu, Yannick; Goddéris, Yves; Ramstein, Gilles; Nédélec, Anne; Meert, Joseph

2004-03-18

231

D-Cluster Converter Foil for Laser-Accelerated Deuteron Beams: Towards Deuteron-Beam-Driven Fast Ignition  

SciTech Connect

Fast Ignition (FI) uses Petawatt laser generated particle beam pulse to ignite a small volume called a pre-compressed Inertial Confinement Fusion (ICF) target, and is the favored method to achieve the high energy gain per target burn needed for an attractive ICF power plant. Ion beams such as protons, deuterons or heavier carbon ions are especially appealing for FI as they have relative straight trajectory, and easier to focus on the fuel capsule. But current experiments have encountered problems with the 'converter-foil' which is irradiated by the Petawatt laser to produce the ion beams. The problems include depletion of the available ions in the convertor foils, and poor energy efficiency (ion beam energy/ input laser energy). We proposed to develop a volumetrically-loaded ultra-high-density deuteron deuterium cluster material as the basis for converter-foil for deuteron beam generation. The deuterons will fuse with the ICF DT while they slow down, providing an extra 'bonus' energy gain in addition to heating the hot spot. Also, due to the volumetric loading, the foil will provide sufficient energetic deuteron beam flux for 'hot spot' ignition, while avoiding the depletion problem encountered by current proton-driven FI foils. After extensive comparative studies, in Phase I, high purity PdO/Pd/PdO foils were selected for the high packing fraction D-Cluster converter foils. An optimized loading process has been developed to increase the cluster packing fraction in this type of foil. As a result, the packing fraction has been increased from 0.1% to 10% - meeting the original Phase I goal and representing a significant progress towards the beam intensities needed for both FI and pulsed neutron applications. Fast Ignition provides a promising approach to achieve high energy gain target performance needed for commercial Inertial Confinement Fusion (ICF). This is now a realistic goal for near term in view of the anticipated ICF target burn at the National Ignition Facility (NIF) in CA within a year. This will usher in the technology development Phase of ICF after years of research aimed at achieving breakeven experiment. Methods to achieve the high energy gain needed for a competitive power plant will then be a key developmental issue, and our D-cluster target for Fast Ignition (FI) is expected to meet that need.

Miley, George H.

2012-10-24

232

Mapping the evolving strain field during continental breakup from crustal anisotropy in the Afar Depression  

PubMed Central

Rifting of the continents leading to plate rupture occurs by a combination of mechanical deformation and magma intrusion, yet the spatial and temporal scales over which these alternate mechanisms localize extensional strain remain controversial. Here we quantify anisotropy of the upper crust across the volcanically active Afar Triple Junction using shear-wave splitting from local earthquakes to evaluate the distribution and orientation of strain in a region of continental breakup. The pattern of S-wave splitting in Afar is best explained by anisotropy from deformation-related structures, with the dramatic change in splitting parameters into the rift axis from the increased density of dyke-induced faulting combined with a contribution from oriented melt pockets near volcanic centres. The lack of rift-perpendicular anisotropy in the lithosphere, and corroborating geoscientific evidence of extension dominated by dyking, provide strong evidence that magma intrusion achieves the majority of plate opening in this zone of incipient plate rupture.

Keir, Derek; Belachew, M.; Ebinger, C.J.; Kendall, J.-M.; Hammond, J.O.S.; Stuart, G.W.; Ayele, A.; Rowland, J.V.

2011-01-01

233

Influence of the Deviation from the Equilibrium Deuteron Distribution on the Neutron Spectra in Linear Pinch Geometries.  

National Technical Information Service (NTIS)

In order to analyse the influence of the deviation from the equilibrium distribution of the fast deuterons on the neutron spectrum, the limiting case, corresponding to a two-dimensional mono-energetic deuteron distribution, was studied. An essential diffe...

R. Deutsch H. Herold H. J. Kaeppeler H. Schmidt

1982-01-01

234

Halo formation and breakup: lessons and open questions  

NASA Astrophysics Data System (ADS)

A quarter of a century's concerted international work in halo physics has resulted in an extended nuclear paradigm encompassing the limits of existence of cold nuclei and also structures beyond—continuum structures of open (nuclear) quantum systems. Realistic working models, based on cluster constituents, have sprung out of the very nature of halo phenomena, in particular from the three-body Borromean property of two-neutron halos, the lack of low-lying binary breakup channels. This has provided transparency and possibility for insight into new quantum behaviour, also in continua beyond driplines—a focus of this status assessment. Breakup spectra and progressively exclusive correlation cross sections can be computed and show, where relevant data exist, not only that general agreement is encouraging but also that some exclusive observables exhibit significant disagreement that has to be clarified. Progress in studies of two-proton emitters has provided another pathway beyond driplines, where again few-body theory appears promising.

Ershov, S. N.; Grigorenko, L. V.; Vaagen, J. S.; Zhukov, M. V.

2010-06-01

235

Systematic Measurement of pd Breakup Cross Section Around Space Star  

NASA Astrophysics Data System (ADS)

Space Star (SS) anomaly in nd breakup cross section was first reported in 1989 at E n = 13 MeV (Strate et al. in Nucl Phys A 501:51, 1989), but its origin has not been found yet. In order to obtain suggestions for its origin, we made systematic measurements of pd breakup cross section around SS. In SS configuration, three outgoing nucleons form an equilateral triangle and the triangle is perpendicular to the beam axis. Necessity of the equilateral and perpendicular conditions of SS anomaly was investigated by systematic experiments. Also energy dependence of SS anomaly is being studied at energies from E p = 7.5 to 13 MeV.

Ohnaka, K.; Sagara, K.; Maeda, Y.; Ishibashi, K.; Kimura, S.; Tanaka, S.; Fukunaga, T.; Yasuda, J.; Yabe, T.; Yashima, K.; Eguchi, Y.; Shimoda, H.; Sueta, T.; Kuroita, S.

2014-04-01

236

Influence of antimisting polymer on aviation fuel breakup  

NASA Technical Reports Server (NTRS)

Experiments have been performed to determine the influence of a moving airstream on jet and drop breakup of fuel containing small concentrations of antimisting polymers. This study was motivated by the needs to inhibit the ignition of fuel during a survivable aircraft crash landing. High speed motion pictures of initial deformation rates and instant pictures of initial deformation rates and instant pictures of the drop breakup suggest that the enormous resistance to the sudden deformation of fuel containing antimisting polymer is related to the development of high tensile viscosity, even though the shear viscosity is not markedly affected. Study of a pendant drop fiber was undertaken to determine this tensile viscosity of antimisting fuel as a function of temperature and of polymer concentration.

Sarohia, V.; Landel, R. F.

1980-01-01

237

Polarized deuteron radiative capture studies of the giant dipole resonance of /sup 16/O  

SciTech Connect

The nature of the intermediate structure observed in the giant dipole resonance of /sup 16/O is investigated through measurement of the radiative capture of polarized deuterons. The angular distributions of the cross section and the four analyzing powers, iT/sub 11/, T/sub 20/, T/sub 21/, and T/sub 22/ for the /sup 14/N(d vector, ..gamma../sub 0/)/sup 16/O reaction are measured for incident deuteron energies in the range 1.7 to 5.5 MeV, corresponding to excitation energies in /sup 16/O of 21.8 to 25.4 MeV. At the peak of the predominant structure in the reaction, a model-independent extraction of the transition matrix elements confirms that the radiation is primarily (approx.85%) isospin forbidden El. The expansion coefficients extracted from the expansion of the angular distributions in terms of Legendre polynomials and associated Legendre functions exhibit strongly fluctuating energy dependence. The energy location and width of this structure is found to be correlated with the structure observed in the nucleon photoabsorption cross section. However, previous interpretations of the intermediate structure in the giant dipole resonance of /sup 16/O as seen in the /sup 15/N(p,..gamma../sub 0/)/sup 16/O and /sup 16/O(..gamma..,n/sub 0/)/sup 15/O reactions are inadequate to explain the energy dependence of the radiative deuteron capture observables. The structure observed in the /sup 14/N(d vector, ..gamma../sub 0/)/sup 16/O reaction is examined in the context of the doorway-state model of Feshback, Kerman and Lemmer. In addition, the experimental results from studies of /sup 16/O with the (p vector, ..gamma../sub 0/), (..cap alpha.., ..gamma../sub 0/), and (/sup 3/He, ..gamma../sub 0/) reactions are combined with the (d vector, ..gamma../sub 0/) measurements in order to obtain a self-consistent description of the reaction mechanism responsible for the intermediate structure in /sup 16/O.

Gossett, C.A.

1983-01-01

238

Spiral breakup in a modified FitzHugh-Nagumo model  

Microsoft Academic Search

In a modified FitzHugh-Nagumo model for excitable tissue a spiral wave is found to break up into an irregular spatial pattern. The main difference between our equations and the standard FitzHugh-Nagumo model is that we use two different time constants: one for the relative refractory period and another for the absolute refractory period. Breakup occurs when the relative refractory period

Alexandre Panfilov; Pauline Hogeweg

1993-01-01

239

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

240

Tidal Breakup of Asteroids by the Earth and Moon  

NASA Technical Reports Server (NTRS)

We report on preliminary results from simulations of the tidal breakup of 'rubble pile' asteroids by the Earth and Moon. We find that both bodies can disrupt 2 g/cm(exp -3) asteroids and the outcome depends on various adjustable factors, including the encounter distance and velocity. The results of the completed study will have implications for the origins of such geological features as crater chains.

Richardson, Derek C.; Bottke, William F., Jr.

1996-01-01

241

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

242

Beam breakup calculations for the second axis of DARHT  

SciTech Connect

The accelerator for the second axis of the Dual Axis Radiographic Hydrodynamic Test (DARHT) facility will produce a 4-kA, 20-MeV, 2-{micro}s output electron beam with a design goal of less than 1000 {pi} mm-mrad normalized transverse emittance and less than 0.5-mm beam centroid motion. In order to meet this goal, the beam transport must have excellent optics and the beam breakup instability (BBU) must be limited in growth. Using a number of simulation codes such as AMOS and BREAKUP, we have modeled the transverse impedances of the DARHT-II accelerator cells and the electron beam response to different transverse excitations such as injector RF noise, magnetic dipole fields arising from the 90-degree bend between the cathode stalk and insulator column, and downstream solenoid alignment errors. The very low Q ({approx}2) predicted for the most important TM dipole modes has prompted us to extend the BREAKUP code to be able to use the dipole wakefields calculated by AMOS in addition to the most usual discrete frequency BBU mode model. We present results for the predicted BBU growth and the empirical sensitivity to various machine parameters.

Fawley, William M.; Chen, Y.-J.; Houck, T.L.

1999-08-20

243

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

244

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

245

Some features of spray breakup in effervescent atomizers  

NASA Astrophysics Data System (ADS)

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

Gadgil, Hrishikesh P.; Raghunandan, B. N.

2011-02-01

246

NAVSPASUR orbital processing for satellite break-up events  

NASA Technical Reports Server (NTRS)

Satellite breakups via explosion or collision can instantly increase the trackable orbiting population by up to several hundred objects, temporarily perturbing the routine space surveillance operations at U.S. Space Command (USSPACWCOM) and the Naval Space Surveillance Center (NAVSPASUR). This paper is a survey of some of the procedures and techniques used by NAVSPASUR to respond to such events. First, the overall data flow at NAVSPASUR is described highlighting the places at which human analysts may intervene with special processing. So-called manual intervention is required in a variety of non-nominal situations, including breakups. Second, a description is given of some of the orbital analysis and other software tools available to NAVSPASUR analysts. These tools were developed in-house over the past thirty years and can be employed in a highly flexible manner. The basic design philosophy for these tools was to implement simple concepts as efficiently as possible and to allow the analyst maximum use of his personal expertise. Finally, several historical breakup scenarios are discussed briefly. These scenarios provide examples of the types of questions that are fairly easy to answer in the present operational environment, as well as examples of questions that are very difficult to answer.

Schumacher, Paul W., Jr.

1991-01-01

247

Examining of the Collision Breakup Model between Geostationary Orbit Objects  

NASA Astrophysics Data System (ADS)

This paper will examine the applicability of the hypervelocity collision model included in the NASA standard breakup model 2000 revision to low-velocity collisions possible in space, especially in the geosynchronous regime. The analytic method used in the standard breakup model will be applied to experimental data accumulated through low-velocity impact experiments performed at Kyushu Institute of Technology at a velocity about 300m/s and 800m/s. The projectiles and target specimens used were aluminum solid balls and aluminum honeycomb sandwich panels with face sheets of carbon fiber reinforced plastic, respectively. Then, we have found that a kind of lower boundary exists on fragment area-to-mass distribution at a smaller characteristic length range. This paper will describe the theoretical derivation of lower boundary and propose another modification on fragment area-to-mass distribution and it will conclude that the hypervelocity collision model in the standard breakup model can be applied to low-velocity collisions possible with some modifications.

Hata, Hidehiro; Hanada, Toshiya; Akahoshi, Yasuhiro; Yasaka, Tetsuo; Harada, Shoji

248

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

NASA Astrophysics Data System (ADS)

We proposed to utilize a new ``Deuterium Cluster'' type structure for the laser interaction foil to generate an energetic deuteron beam as the fast igniter to ignite inertial confinement fusion fuel capsule. The benefit of deuteron beam driven fast ignition is that its deposition in the target fuel will not only provide heating but also fuse with fuel as they slow down in the target. The preliminary results from recent laser-deuteron acceleration experiment at LANL were encouraging. Also, in most recent calculations, we found that a 12.73% extra energy gain from deuteron beam-target fusion could be achieved when quasi-Maxwellian deuteron beam was assumed, and when a ?rb = 4.5 g/cm2 was considered, where ? is the fuel density, and rb is the ion beam focusing radius on the target. These results provide some insight into the contribution of the extra heat produced by deuteron beam-target fusion to the hot spot ignition process. If the physics works as anticipated, this novel type of interaction foil can efficiently generate energetic deuterons during intense laser pulses. The massive yield of deuterons should turn out to be the most efficient way of igniting the DT fuel, making the dream of near-term commercialization of FI fusion more achievable.

Yang, Xiaoling; Miley, George; Flippo, Kirk; Hora, Heinrich; Gaillard, Sandrine; Offermann, Dustin

2012-10-01

249

Recent results with polarized deuterons and polarimetry at Nuclotron-NICA  

NASA Astrophysics Data System (ADS)

Recent results on the deuteron analyzing powers obtained in collisions of polarized deuterons with protons and light nuclei at intermediate and high energies are reported. The obtained results are sensitive to the spin structure of the short range correlations. The prospects of the spin program for hadronic reactions at Nuclotron-NICA facility is discussed. The polarimetry developments are also presented.

Ladygin, V. P.; Uesaka, T.; Glagolev, V. V.; Gurchin, Yu V.; Isupov, A. Yu; Itoh, K.; Janek, M.; Karachuk, J.-T.; Kawabata, T.; Khrenov, A. N.; Kiselev, A. S.; Kizka, V. A.; Kurepin, A. B.; Kurilkin, A. K.; Kurilkin, P. K.; Krasnov, V. A.; Ladygina, N. B.; Lipchinski, D.; Livanov, A. N.; Maeda, Y.; Malakhov, A. I.; Martinska, G.; Nedev, S.; Piyadin, S. M.; Plekhanov, E. B.; Popovichi, J.; Rangelov, S.; Reznikov, S. G.; Rukoyatkin, P. A.; Sakaguchi, S.; Sakai, H.; Sekiguchi, K.; Shikhalev, M. A.; Suda, K.; Terekhin, A. A.; Urban, J.; Vasiliev, T. A.; Vnukov, I. E.; Witala, H.

2011-05-01

250

Long time experience of polarized deuteron source polaris at the JINR synchrophasotron  

SciTech Connect

Since 1981 the JINR 4.5 GeV/nucleon synchrophasotron accelerates a polarized deuteron beam. A cryogenic source of a polarized deuterons POLARIS and some experimental equipment used for this purpose are briefly described. {copyright} {ital 1995 American Institute of Physics.}

Ershov, V.P.; Fimushkin, V.V.; Kulikov, M.V.; Pilipenko, Y.K.; Shutov, V.B.; Valevich, A.I. [Joint Institute for Nuclear Research, Dubna, Moscow Region, RU-141980 (Russia)

1995-09-01

251

One-Step Acceleration of Deuterons and alpha -Particles at the JINR Synchrophasotron.  

National Technical Information Service (NTIS)

The problems are considered which are related to one-step acceleration mode of deuterons and alpha -particles at the JINR synchrophasotron. The one-step mode of acceleration of deuteron and alpha -particles has been realized by widening the driving oscill...

A. I. Mikhailov G. P. Puchkov K. V. Chekhlov

1976-01-01

252

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

253

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

254

Propagation of trans-equatorial deuteron whistlers in the low latitude topside ionosphere  

NASA Technical Reports Server (NTRS)

The high latitude limit of transequatorial deuteron whistlers is found to occur at latitudes where B(m) = B/2, in which B is the local magnetic field at the satellite and B(m) is the minimum magnetic field on the field line through the satellite. The high latitude limit of transequatorial proton whistlers, often extends to the latitude where B(m) = B/4 in the autumn and winter. Transequatorial deuteron whistlers have a constant time interval for an echo train. The damping rate of the cyclotron resonant interaction with rare deuteron is large enough to generate deuteron whistlers. Ray tracing results for nonducted propagation of transequatorial deuteron whistlers show that rays are guided by the geomagnetic field within one degree in invariant latitude for several bounces between the two hemispheres.

Watanabe, S.; Ondoh, T.

1980-01-01

255

Scaling for deuteron structure functions in a relativistic light-front model  

SciTech Connect

Scaling limits of the structure functions [B.D. Keister, Phys. Rev. C {bold 37}, 1765 (1988)], {ital W}{sub 1} and {ital W}{sub 2}, are studied in a relativistic model of the two-nucleon system. The relativistic model is defined by a unitary representation, {ital U}({Lambda},{ital a}), of the Poincar{acute e} group which acts on the Hilbert space of two spinless nucleons. The representation is in Dirac{close_quote}s [P.A.M. Dirac, Rev. Mod. Phys. {bold 21}, 392 (1949)] light-front formulation of relativistic quantum mechanics and is designed to give the experimental deuteron mass and {ital n}-{ital p} scattering length. A model hadronic current operator that is conserved and covariant with respect to this representation is used to define the structure tensor. This work is the first step in a relativistic extension of the results of Hueber, Gl{umlt o}ckle, and Boemelburg. The nonrelativistic limit of the model is shown to be consistent with the nonrelativistic model of Hueber, Gl{umlt o}ckle, and Boemelburg. [D. Hueber {ital et} {ital al}. Phys. Rev. C {bold 42}, 2342 (1990)]. The relativistic and nonrelativistic scaling limits, for both Bjorken and {ital y} scaling are compared. The interpretation of {ital y} scaling in the relativistic model is studied critically. The standard interpretation of {ital y} scaling requires a soft wave function which is not realized in this model. The scaling limits in both the relativistic and nonrelativistic case are related to probability distributions associated with the target deuteron. {copyright} {ital 1996 The American Physical Society.}

Polyzou, W.N. [Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52246 (United States)] [Department of Physics and Astronomy, University of Iowa, Iowa City, Iowa 52246 (United States); Gloeckle, W. [Institut fuer Theoretische Physik II, Ruhr-Universitaet, D-4630 Bochum (Germany)] [Institut fuer Theoretische Physik II, Ruhr-Universitaet, D-4630 Bochum (Germany)

1996-06-01

256

Forward antiproton-deuteron elastic scattering and total spin-dependent antiproton-deuteron cross sections at intermediate energies  

Microsoft Academic Search

Spin-dependent total pbar-d cross sections are considered using the optical\\u000atheorem. For this aim the full spin dependence of the forward pbar-d elastic\\u000ascattering amplitude is considered in a model independent way. The\\u000asingle-scattering approximation is used to relate this amplitude to the\\u000aelementary amplitudes of pbar-p and pbar-n scattering and the deuteron form\\u000afactor. A formalism allowing to take

Yu. N. Uzikov; J. Haidenbauer

2008-01-01

257

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

258

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

259

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

260

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

261

Continental break-up in Ethiopia: results from the EAGLE experiment  

NASA Astrophysics Data System (ADS)

The rifting of continents and eventual formation of ocean basins is a fundamental component of plate tectonics, yet the mechanism for break-up has, until recently, been poorly understood. The East Africa Rift system (EARS) is an ideal place to study this process since it captures the initiation of a rift in the south through to incipient oceanic spreading in northern Ethiopia. Here we present the results of EAGLE (Ethiopia, Afar, Geoscientific, Lithospheric Experiment), a multi-disciplinary project that aimed to study the anatomy of a rift immediately prior to break-up. Also presented here are the results of a new P wave tomographic inversion for Ethiopia that utilizes broadband seismological data from both the EAGLE and Penn State University Ethiopia networks. With up to 100 stations, a network aperture of ~1000km, and more than three years of continuous seismic data, we are able to present the most detailed picture to date of the upper mantle velocity structure beneath a region of incipient lithospheric rupture. Mantle and crustal tomography studies, magnetotelluric, gravity, and seismic anisotropy studies all indicate localized zones of magma intrusion beneath the rift, with the shallowest levels of intrusion beneath the seismically and volcanically active tectono-magmatic segments in the rift valley. The intimate relationship between faulting and magmatism in the northern MER is strikingly similar to that of slow-spreading mid-ocean ridges, but without the hard linkage zones of transform faults. Seismological, gravity, magnetotelluric, geochemical and structural observations all point to fundamental modification of crust and upper mantle by magma intrusion during the syn-rift stage. These observations support models of magma assisted rifting, rather than those of simple mechanical stretching.

Bastow, I. D.; Ebinger, C. J.; Maguire, P. K.; Stuart, G. W.; Keller, G. R.; Kendall, J. M.; Klemperer, S. L.; Whaler, K. A.; Asfaw, L. M.; Nyblade, A. A.; Benoit, M. H.; Group, E. W.

2006-05-01

262

Assessing river ice breakup date, coastal tundra vegetation and climate divisions in the context of Alaska climate variability  

NASA Astrophysics Data System (ADS)

In Alaska, there exists a substantial knowledge gap of key climate drivers and filling these gaps is vital since life and the economy are inexorably linked with climate in the state. This thesis identifies and investigates three topics that advance the understanding of Alaska climate variability: the role of large-scale climate in Interior river ice breakup, the link between climate and arctic tundra vegetation, and climate divisions based on objective methods. River ice breakup in the Yukon-Kuskoswim watershed is occurring earlier by 1.3 days decade-1 1948-2008 and displays large year-to-year variability. April-May Interior Alaska air temperatures are the best predictor of river ice breakup and were linked to El Niño Southern Oscillation (ENSO). During the warm phase of ENSO, fewer storms track into the Gulf of Alaska during Boreal Spring, resulting in reduced April-May cloudiness over Alaska, increased solar insolation at the land surface, warmer air temperatures and consequently earlier breakup. Northern Alaska tundra vegetation productivity has increased 1982-2011, based on the Normalized Difference Vegetation Index (NDVI), a satellite measure of vegetation correlated with above ground biomass. Vegetation productivity was linked to the Beaufort High circulation as well as snowfall, in addition to land surface temperatures and coastal sea ice extent. NDVI has decreased from 1982-2011 over the coastal tundra along the Bering Sea and was correlated with delayed springtime warming due to enhanced coastal sea ice and a delayed snowmelt. Cluster analysis was applied to 2-meter air temperature data 1977-2010 at meteorological stations to construct climate divisions for Alaska. Stations were grouped together objectively based on similar homogeneous seasonal and annual climate variability and were refined using local expert knowledge to ultimately identify 13 divisions. Correlation analysis using gridded downscaled temperature and precipitation data validated the final division lines and documented that each division has similar a similar annual cycle in temperature and precipitation. Overall, this work documented substantial links and identified mechanisms joining the large-scale climate to that of Alaska. A better understanding of the role of large-scale climate variability in river ice breakup or tundra greening holds promise for developing seasonal and longer-term forecasts.

Bieniek, Peter A.

263

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

264

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

PubMed

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 et al., Soft Matter 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. PMID:22680486

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

2012-04-01

265

North Atlantic Margins: Case studies of Magmatic Continental Breakup  

NASA Astrophysics Data System (ADS)

Continental breakup between Europe and Greenland was accompanied by the rapid eruption of the > 1 million cubic kilometres of extruded basalts forming North Atlantic Igneous Province. With episodes of extension in the region dating back to the Devonian, rifting finally proceeded to full breakup and oceanic spreading in the Paleocene. Flood basalt units flowed up to 150 km over pre-existing sedimentary basins, discrete volcanic centres formed and intrusion into the thinned continental crust occurred. Marine seismic investigations utilising industry-leading seismic reflection imaging technologies and large deployments of ocean bottom seismometers across the Faroes and Hatton Bank margins have been used to better resolve margin structure and composition, improving our understanding of breakup processes. Seismic reflection imaging reveals sub-aerial and submarine seaward-dipping reflector sequences tracking the interplay of uplift (transient and permanent), crustal loading through extrusion and ongoing extension. Lower crustal reflectors, cross-cutting the continental fabric and interpreted as intrusions, are observed within the narrow continent-ocean transition. P-wave tomography of wide-angle reflections and refractions, recorded to offsets of up to ~200 km, reveals unusually thick oceanic crust with lower crustal velocities in excess of those expected for MORB compositions. High P-wave velocities are attributed to magnesium-rich compositions which, combined with the large oceanic crustal thickness, would be consistent with an elevated mantle temperature (~150°C higher than 'normal') at the time of breakup. Vp/Vs ratios derived from tomography of converted shear wave phases also support high magnesium melt composition. P-wave velocities and Vp/Vs ratios across the continent-ocean transition show a mixing trend between magnesium-rich gabbroic compositions (100% for oceanic crust) and compositions consistent with the Lewisian gneiss basement or Early Proterozoic metamorphic basement of the Faroes and Hatton Bank areas respectively. Sedimentary units forming a low velocity zone beneath the flood basalts across the Faroe Ridge and into the Faroe-Shetland Trough are hypothesised to represent Paleocene sedimentary rock emplaced as transient thermal uplift across the nascent rift zone led to increased weathering and clastic sediment transport from Greenland.

Eccles, J. D.; White, R. S.; Christie, P. A. F.

2012-04-01

266

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.

267

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

268

Void deformation and breakup in shearing silica glass.  

PubMed

We study shear deformation and breakup of voids in silica glass using molecular dynamics simulations. With an increase in the shear strain, two kinds of defects--threefold-coordinated silicon and nonbridging oxygen atoms--appear as spherical voids deform elastically into ellipsoidal shapes. For shear strains epsilon>15%, nanocracks appear on void surfaces and voids deform plastically into a threadlike structure. Nanocracks are nucleated by the migration of threefold-coordinated Si and nonbridging O on -Si-O-Si-O- rings. For epsilon>40%, the threadlike structures break up into several fragments. PMID:19659293

Chen, Yi-Chun; Nomura, Ken-ichi; Kalia, Rajiv K; Nakano, Aiichiro; Vashishta, Priya

2009-07-17

269

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

270

Complete set of deuteron analyzing powers for dp elastic scattering at intermediate energies  

NASA Astrophysics Data System (ADS)

With the aim of clarifying roles of the 3NFs in nuclei experimental programs with polarized deuterons beams at intermediate energies are in progress at RIKEN RI Beam Factory. As the first step, we have measured a complete set of deuteron analyzing powers ( iT 11, T 20, T 21, T 22) in deuteron-proton elastic scattering at 250 and 294 MeV/nucleon. The obtained data are compared with the Faddeev calculations based on the modern nucleon-nucleon forces together with the Tucson-Melbourne'99, and UrbanaIX three nucleon forces.

Sekiguchi, K.; Okamura, H.; Wada, Y.; Miyazaki, J.; Taguchi, T.; Gebauer, U.; Dozono, M.; Kawase, S.; Kubota, Y.; Lee, C. S.; Maeda, Y.; Mashiko, T.; Miki, K.; Sakaguchi, S.; Sakai, H.; Sakamoto, N.; Sasano, M.; Shimizu, Y.; Takahashi, K.; Tang, R.; Uesaka, T.; Wakasa, T.; Yako, K.

2014-01-01

271

Spin structure of the deuteron from the [ital [rvec d][rvec p  

SciTech Connect

The polarization observables in the elastic scattering of polarized deuterons on a polarized hydrogen target, with measurement of the recoil proton polarization, are considered. The observables are calculated in the one-nucleon exchange approximation, for the special case of backward scattering ([theta][sub c.m.]=180[degree]). Several new relations between polarization observables of the reaction are derived within the framework of this approximation. These relations can be used for detailed study of the deuteron structure and/or deuteron interaction at intermediate energy.

Kobushkin, A.P.; Syamtomov, A.I. (N. N. Bogulyubov Institute for Theoretical Physics, 252143 Kiev (Ukraine)); Perdrisat, C.F. (College of William and Mary, Williamsburg, Virginia 23185 (United States)); Punjabi, V. (Norfolk State University, Norfolk, Virginia 23504 (United States))

1994-11-01

272

Measurement of inelastic cross sections in relativistic deuteron-on-lead reactions  

SciTech Connect

The inelastic cross section of deuterons hitting a lead target has been determined by the beam attenuation technique. A spallation neutron source based on a lead target was irradiated with 1.6- and 2.5-GeV deuterons. Solid-state nuclear track detectors as well as the activation method were used to obtain the neutron and proton distribution along the surface of the source. The attenuation coefficient was estimated by fitting the experimental data and taking into account the buildup effect and the beam attenuation. Using the attenuation coefficient, the interaction length and then the inelastic cross section of deuterons on lead reaction were determined.

Zamani, M.; Stoulos, S.; Fragopoulou, M. [Aristotle University of Thessaloniki, School of Physics, GR-54 124 Thessaloniki (Greece); Krivopustov, M. [Joint Institute for Nuclear Research, Dubna 141980 (Russian Federation)

2010-10-15

273

An investigation of soft launch and instability breakup with a two-stage light gas gun  

Microsoft Academic Search

Exploratory research has been performed in the use of a two-stage light gas gun facility to investigate the soft acceleration and breakup physics of rapidly launched thin plates. A flash radiograph system was joined with the gun facility to provide the principal diagnostic. In the study, radiographs of thin-plate acceleration and breakup were obtained.

D. E. Grady; R. L. Moody

1988-01-01

274

The effects of nozzle geometry on waterjet breakup at high Reynolds numbers  

Microsoft Academic Search

Waterjet breakup is traditionally considered to follow the Ohnesorge classification. In this classification, high Reynolds number waterjets are considered to atomize quickly after discharge. By generating a constricted waterjet where the water flow stays detached all the way through the nozzle, we have observed the first wind-induced breakup mode at high Reynolds numbers. Such a peculiar behavior, however, was not

H. Vahedi Tafreshi; B. Pourdeyhimi

2003-01-01

275

Numerical simulation of primary break-up and atomization: DNS and modelling study  

Microsoft Academic Search

This work deals with numerical simulations of atomization with high Weber and Reynolds values. A special attention has been devoted to the modelling of primary break-up. Due to progress of direct numerical simulations (DNS) of two phase flows it is now possible to simulate the primary break-up of a Diesel spray [Menard, T., Tanguy, S., Berlemont, A., 2007. Coupling level

R. Lebas; T. Menard; P. A. Beau; A. Berlemont; F. X. Demoulin

2009-01-01

276

Theoretical and empirical analysis of the average cross-sectional areas of breakup fragments  

Microsoft Academic Search

This paper compares two different approaches to calculate the average cross-sectional area of breakup fragments. The first one is described in the NASA standard breakup model 1998 revision. This approach visually classifies fragments into several shapes, and then applies formulae developed for each shape to calculate the average cross-sectional area. The second approach was developed jointly by the Kyushu University

T. Hanada; J.-C. Liou

2011-01-01

277

Examining Applicability of the NASA Standard Breakup Model to Low-Velocity Collisions  

Microsoft Academic Search

The data from a series of low-velocity collision experiments performed at Kyushu University will be re-analyzed based on the method used in the National Aeronautics and Space Administration (NASA) standard breakup model 2000 revision to be compared with the hypervelocity collision model adopted in the NASA standard breakup model. The results will indicate that the NASA hypervelocity collision model can

Hidehiro Hata; Yasuo Kurakazu; Toshiya Hanada; Yasuhiro Akahoshi; Tetsuo Yasaka; Shoji Harada

2004-01-01

278

Precision Measurement of the Deuteron Spin Structure Function gd1  

NASA Astrophysics Data System (ADS)

We report on a high-statistics measurement of the deuteron spin structure function gd1 at a beam energy of 29 GeV in the kinematic range 0.029

Abe, K.; Akagi, T.; Anthony, P. L.; Antonov, R.; Arnold, R. G.; Averett, T.; Band, H. R.; Bauer, J. M.; Borel, H.; Bosted, P. E.; Breton, V.; Button-Shafer, J.; Chen, J. P.; Chupp, T. E.; Clendenin, J.; Comptour, C.; Coulter, K. P.; Court, G.; Crabb, D.; Daoudi, M.; Day, D.; Dietrich, F. S.; Dunne, J.; Dutz, H.; Erbacher, R.; Fellbaum, J.; Feltham, A.; Fonvieille, H.; Frlez, E.; Garvey, D.; Gearhart, R.; Gomez, J.; Grenier, P.; Griffioen, K. A.; Hoibraten, S.; Hughes, E. W.; Hyde-Wright, C.; Johnson, J. R.; Kawall, D.; Klein, A.; Kuhn, S. E.; Kuriki, M.; Lindgren, R.; Liu, T.; Lombard-Nelsen, R. M.; Marroncle, J.; Maruyama, T.; Maruyama, X. K.; McCarthy, J.; Meyer, W.; Meziani, Z.-E.; Minehart, R.; Mitchell, J.; Morgenstern, J.; Petratos, G. G.; Pitthan, R.; Pocanic, D.; Prescott, C.; Prepost, R.; Raines, P.; Raue, B.; Reyna, D.; Rijllart, A.; Roblin, Y.; Rochester, L. S.; Rock, S. E.; Rondon, O. A.; Sick, I.; Smith, L. C.; Smith, T. B.; Spengos, M.; Staley, F.; Steiner, P.; St. Lorant, S.; Stuart, L. M.; Suekane, F.; Szalata, Z. M.; Tang, H.; Terrien, Y.; Usher, T.; Walz, D.; White, J. L.; Witte, K.; Young, C. C.; Youngman, B.; Yuta, H.; Zapalac, G.; Zihlmann, B.; Zimmermann, D.

1995-07-01

279

Quasimonoenergetic Deuteron Bursts Produced by Ultraintense Laser Pulses  

SciTech Connect

We report on the generation and laser acceleration of bunches of energetic deuterons with a small energy spread at about 2 MeV. This quasimonoenergetic peak within the ion energy spectrum was observed when heavy-water microdroplets were irradiated with ultrashort laser pulses of about 40 fs duration and high (10{sup -8}) temporal contrast, at an intensity of 10{sup 19} W/cm{sup 2}. The results can be explained by a simple physical model related to spatial separation of two ion species within a finite-volume target. The production of quasimonoenergetic ions is a long-standing goal in laser-particle acceleration; it could have diverse applications such as in medicine or in the development of future compact ion accelerators.

Ter-Avetisyan, S.; Schnuerer, M.; Nickles, P.V.; Kalashnikov, M.; Risse, E.; Sokollik, T.; Sandner, W. [Max-Born-Institut, Berlin, Max-Born-Strasse 2a, D-12489, Berlin (Germany); Andreev, A. [Vavilov State Optical Institute, 12, Birzhevaya Line, St. Petersburg 199034 (Russian Federation); Tikhonchuk, V. [Centre Lasers Intenses et Applications, UMR 5107, Universite Bordeaux 1- CNRS-CEA, 33405 Talence (France)

2006-04-14

280

Polarization observables in exclusive kaon photoproduction on the deuteron  

SciTech Connect

Single and double polarization observables for kaon photoproduction on the deuteron are studied theoretically with modern hyperon-nucleon forces. The kinematical region of the kaon scattered forward with large momentum is thoroughly investigated where either the quasifree scattering leading to the kaon and hyperon or the final-state interaction between hyperon and nucleon are expected. The quasifree scatterings show characteristic peaks in the inclusive cross sections. The final-state interaction effects are significant, especially around the {lambda}N and {sigma}N thresholds. The double polarization C{sub z} is found to be sensitive to the final-state interaction effects. Precise data would help to clarify the property of the {lambda}N-{sigma}N interaction and also help to extract the information on the elementary amplitude from the quasifree scattering region.

Miyagawa, K.; Mart, T.; Bennhold, C.; Gloeckle, W. [Department of Applied Physics, Okayama University of Science, 1-1 Ridai-cho, Okayama 700 (Japan); Departemen Fisika, FMIPA, Universitas Indonesia, Depok 16424 (Indonesia); Center for Nuclear Studies, Department of Physics, George Washington University, Washington, D.C. 20052 (United States); Institut fuer Theoretische Physik II, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany)

2006-09-15

281

Distribution of living Cupressaceae reflects the breakup of Pangea  

PubMed Central

Most extant genus-level radiations in gymnosperms are of Oligocene age or younger, reflecting widespread extinction during climate cooling at the Oligocene/Miocene boundary [?23 million years ago (Ma)]. Recent biogeographic studies have revealed many instances of long-distance dispersal in gymnosperms as well as in angiosperms. Acting together, extinction and long-distance dispersal are likely to erase historical biogeographic signals. Notwithstanding this problem, we show that phylogenetic relationships in the gymnosperm family Cupressaceae (162 species, 32 genera) exhibit patterns expected from the Jurassic/Cretaceous breakup of Pangea. A phylogeny was generated for 122 representatives covering all genera, using up to 10,000 nucleotides of plastid, mitochondrial, and nuclear sequence per species. Relying on 16 fossil calibration points and three molecular dating methods, we show that Cupressaceae originated during the Triassic, when Pangea was intact. Vicariance between the two subfamilies, the Laurasian Cupressoideae and the Gondwanan Callitroideae, occurred around 153 Ma (124–183 Ma), when Gondwana and Laurasia were separating. Three further intercontinental disjunctions involving the Northern and Southern Hemisphere are coincidental with or immediately followed the breakup of Pangea.

Mao, Kangshan; Milne, Richard I.; Zhang, Libing; Peng, Yanling; Liu, Jianquan; Thomas, Philip; Mill, Robert R.; S. Renner, Susanne

2012-01-01

282

Distribution of living Cupressaceae reflects the breakup of Pangea.  

PubMed

Most extant genus-level radiations in gymnosperms are of Oligocene age or younger, reflecting widespread extinction during climate cooling at the Oligocene/Miocene boundary [?23 million years ago (Ma)]. Recent biogeographic studies have revealed many instances of long-distance dispersal in gymnosperms as well as in angiosperms. Acting together, extinction and long-distance dispersal are likely to erase historical biogeographic signals. Notwithstanding this problem, we show that phylogenetic relationships in the gymnosperm family Cupressaceae (162 species, 32 genera) exhibit patterns expected from the Jurassic/Cretaceous breakup of Pangea. A phylogeny was generated for 122 representatives covering all genera, using up to 10,000 nucleotides of plastid, mitochondrial, and nuclear sequence per species. Relying on 16 fossil calibration points and three molecular dating methods, we show that Cupressaceae originated during the Triassic, when Pangea was intact. Vicariance between the two subfamilies, the Laurasian Cupressoideae and the Gondwanan Callitroideae, occurred around 153 Ma (124-183 Ma), when Gondwana and Laurasia were separating. Three further intercontinental disjunctions involving the Northern and Southern Hemisphere are coincidental with or immediately followed the breakup of Pangea. PMID:22550176

Mao, Kangshan; Milne, Richard I; Zhang, Libing; Peng, Yanling; Liu, Jianquan; Thomas, Philip; Mill, Robert R; Renner, Susanne S

2012-05-15

283

Study of the Breakup Reaction ⁸Bâ{sup {bold 7}}Be{bold +}{ital p}: Absorption Effects and {ital E{bold 2}} Strength  

Microsoft Academic Search

Distributions of parallel and transverse momenta for ⁷Be fragments formed in the breakup of ⁸B have been measured at 41A MeV. The {ital p}{sub â¥} distributions are narrow (81±4 and 62±3MeV\\/{ital c} FWHM for Be and Au targets, respectively), comparable to those of neutron halo nuclei. Reaction mechanisms influence the ⁷Be momentum distributions, so they do not directly reflect the

J. H. Kelley; S. M. Austin; A. Azhari; D. Bazin; J. A. Brown; H. Esbensen; M. Fauerbach; M. Hellstroem; S. E. Hirzebruch; R. A. Kryger; D. J. Morrissey; R. Pfaff; C. F. Powell; E. Ramakrishnan; B. M. Sherrill; M. Steiner; T. Suomijaervi; M. Thoennessen

1996-01-01

284

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

285

Azimuthal structure of substorm breakup arcs prior to expansive phase onset using ISUAL/FORMOSAT-2  

NASA Astrophysics Data System (ADS)

Substorm breakup arcs are investigated for substorm onset that occurs at the location of "Harang discontinuity" at pre-midnight. The auroral breakup arc images are obtained by the Imager of Sprites and Upper Atmospheric Lightning (ISUAL) onboard FORMOSAT-2 satellite. We identify that the auroral breakup arc brightening occurs at the same time as the associated negative H-Bay and Pi 2 pulsations. It begins with a brightening on the arc and evolves into clear bead-like structure with approximate equally spaced separation along the arc direction. The enhanced auroral arcs finally break up into several parts. The azimuthal mode number of auroral breakup arcs prior to expansive phase onset ranges from ~200 to ~300. Based on the observations, we suggest that the substorm initial breakup arcs are consistent with kinetic ballooning instability, which is localized at the center of cross tail current sheet at about -(8-10) RE for strong substorms.

Chang, T.; Cheng, C.; Chiang, C.; Tam, S. W.; Chen, A. B.; Hsu, R.; Su, H.

2008-12-01

286

Near Term Effects from Satellite Break-Ups on Manned Space Activities  

NASA Technical Reports Server (NTRS)

Since 1961, almost 160 satellite break-ups have occurred on-orbit, and have been the major contributor to the growth of the orbital debris population. When a satellite breaks up, the debris exists in a relatively concentrated form, orbiting in a loose cloud with the parent body until orbital perturbations disperse the cloud into the average background. Manned space activities, which usually take place in low Earth orbit at altitudes less than 500 km, have been continuous for the past I I years while Mir was inhabited and promise to be again continuous when the International Space Station becomes permanently manned. This paper surveys historical breakups over the last I I years to determine the number that affect altitudes lower than 500 km. Selected breakup are analyzed using NASA's Satellite Breakup Risk Assessment Model (SBRAM) to determine the specific short term risk from those breakups to manned missions.

Theall, J. R.; Matney, M. J.

2000-01-01

287

Development of a droplet breakup model considering aerodynamic and droplet collision effects  

NASA Technical Reports Server (NTRS)

A model is currently under development to predict the occurrence and outcome of spray droplet breakup induced by aerodynamic forces and droplet collisions. It is speculated that these phenomena may be significant in determining the droplet size distribution in a spray subjected to acoustic velocity fluctuations. The goal is to integrate this breakup model into a larger spray model in order to examine the effects of combustion instabilities on liquid rocket motor fuel sprays. The model is composed of three fundamental components: a dynamic equation governing the deformation of the droplet, a criterion for breakage based on the amount of deformation energy stored in the droplet and an energy balance based equation to predict the Sauter mean diameter of the fragments resulting from breakup. Comparison with published data for aerodynamic breakup indicates good agreement in terms of predicting the occurrence of breakup. However, the model significantly over predicts the size of the resulting fragments. This portion of the model is still under development.

Wert, K. L.; Jacobs, H. R.

1993-01-01

288

Determination of the ^1S0 Neutron-Neutron Scattering Length Using nd Breakup in Recoil Geometry at 19 MeV  

NASA Astrophysics Data System (ADS)

There is a significant discrepancy between the recent measurements of the ^1S0 neutron-neutron (nn) scattering length (ann). González Trotter et al. [1] reported a value of ann= -18.7 ±0.6 fm from their nn coincidence cross-section measurements at a neutron beam energy of 13 MeV, while Huhn et al. [2] obtained ann= -16.3 ±0.4 fm from their nn final-state interaction (FSI) cross-section measurements made at 25 MeV using proton recoil geometry. We report the preliminary results of a new determination of ann at 19 MeV at TUNL made using the neutron-deuteron breakup reaction in recoil proton geometry. The recoil proton and one of the outgoing neutrons were detected in coincidence and their energies were measured using time-of-flight techniques. Details of the experiment, analysis, and preliminary results will be presented. [1] D.E. González Trotter et al., Phys. Rev. C 73, 034001 (2006). [2] V.H. Huhn et al., Phys. Rev. Lett. 85, 1190 (2000).

Tajima, S.; Crowell, A. S.; Deng, J.; Esterline, J.; Howell, C. R.; Kiser, M. R.; Macri, R. A.; Tornow, W.; Crowe, B. J., III; Pedroni, R. S.; von Witsch, W.; Wita?a, H.

2009-11-01

289

Radiative corrections to polarization observables in elastic electron-deuteron scattering in leptonic variables  

SciTech Connect

The model-independent QED radiative corrections to polarization observables in elastic scattering of unpolarized and longitudinally polarized electron beams by a deuteron target are calculated in leptonic variables. The experimental setup when the deuteron target is arbitrarily polarized is considered and the procedure for applying the derived results to the vector or tensor polarization of the recoil deuteron is discussed. The calculation is based on taking all essential Feynman diagrams into account, which results in the form of the Drell-Yan representation for the cross section, and the use of the covariant parameterization of the deuteron polarization state. Numerical estimates of the radiative corrections are given in the case where event selection allows undetected particles (photons and electron-positron pairs) and the restriction on the lost invariant mass is used.

Gakh, G. I.; Konchatnij, M. I., E-mail: konchatnij@kipt.kharkov.ua; Merenkov, N. P., E-mail: merenkov@kipt.kharkov.ua [Kharkov Institute of Physics and Technology (Ukraine)

2012-08-15

290

Electrodisintegration of the deuteron near threshold with allowance for meson exchange currents. Retardation effects.  

National Technical Information Service (NTIS)

The electrodisintegration of the deuteron near threshold with allowance for retardation effects in meson exchange currents (MEC) has been investigated depending on vertex form factors and cut-off parameters. It is shown that the retardation effects should...

V. V. Burov S. Sus'kov A. A. Goj

1992-01-01

291

Deuteron NMR and a model for phase transitions in monoclinic RbD2PO4  

NASA Astrophysics Data System (ADS)

The quadrupole-perturbed deuteron NMR spectra and spin-lattice relaxation times of monoclinic RbD2PO4 have been measured and the electric-field-gradient tensors at the deuteron sites have been determined in phase I at 110 °C, phase III at 80 °C, and phase III at 40 °C. The results are incompatible with a location of the D(2) and D(3) deuterons in the center of the corresponding H bonds. They show that these deuterons are disordered between two off-center sites in phases I and II, whereas they are ordered in phases III and IV. A four-sublattice model accounting for all four phase transitions in monoclinic RbD2PO4 is proposed.

Jarh, O.; Dolinšek, J.; Topi?, B.; Žekš, B.; Blinc, R.; Schmidt, V. H.; Shuvalov, L. A.; Baranov, A.

1989-02-01

292

Microscopic study of deuteron-nucleus total reaction cross section at medium energies  

NASA Astrophysics Data System (ADS)

Total reaction cross sections for 38, 67 and 97 MeV deuteron for several nuclei have been analyzed within the theoretical framework of the Glauber model. The Glauber elastic S-matrix element to the deuteron-nucleus system is evaluated in the rigid projectile model which takes as the input N-d elastic scattering amplitude evaluated in terms of the nucleon-nucleon amplitude and ground state density of the deuteron. The analysis takes into consideration the Coulomb modification of the projectile trajectory, downward energy shift of the projectile nucleon due to the Coulomb field and the modification on nucleon-nucleon total cross section. The contribution to the total reaction cross section from the photo-disintegration of the deuteron is also considered. Using the semi-phenomenological proton and neutron densities for the target, we find that in general, the theoretical predictions are in fairly good agreement with the experimental data.

Madani, Jamal H.; Ahmad, I.; Alvi, M. A.

2010-08-01

293

Measurement of the Tensor Analyzing Power for Relativistic-Deuteron Fragmentation as a Means for Studying the Deuteron Structure within Light-Front Dynamics  

SciTech Connect

New data on the vector (A{sub y}) and tensor (A{sub yy}) analyzing powers for the reaction {sup 9}Be (d, p)X at a primary deuteron momentum of 5 GeV/c for a proton emission angle of 178 mrad are obtained by using the synchrophasotron of the Joint Institute for Nuclear Research (JINR, Dubna). The experimental data on A{sub yy} are analyzed within the approach based on light-front dynamics, the relativistic wave function obtained by Karmanov and his colleagues being used for the deuteron. It is shown that, in contrast to what one has from calculations with standard nonrelativistic deuteron wave functions, all relevant data can be explained in this approximation without resort to additional degrees of freedom.

Azhgirey, L.S.; Afanasiev, S.V.; Zhmyrov, V.N.; Zolin, L.S.; Ivanov, V.I.; Isupov, A.Yu.; Ladygin, V.P.; Litvinenko, A.G.; Peresedov, V.F.; Khrenov, A.N. [Joint Institute for Nuclear Research, Dubna, Moscow oblast, 141980 (Russian Federation); Yudin, N.P. [Institute of Nuclear Physics, Moscow State University, Vorob'evy gory, Moscow, 119899 (Russian Federation)

2005-12-01

294

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

295

Neutron distributions from the deuteron bombardment of a thick beryllium target  

Microsoft Academic Search

The energy spectrum of neutrons emitted when deuterons impinge on a thick beryllium target has been measured using an NE213 scintillation detector and the time-of-flight technique. Spectra have been measured at angles of 0, 30, 45, 60, 90, 120 and 150 degrees and deuteron energies of 1.4, 1.8, 2.3 and 2.8 MeV. Results presented are angular yields and angle-integrated energy

S. Whittlestone

1977-01-01

296

Neutron spectra from deuteron and proton bombardment of thick lithium targets: potential for neutron therapy  

Microsoft Academic Search

Neutron energy spectra and yields produced by the bombardment of thick lithium targets by deuterons and protons have been measured using the time-of-flight method. Measurements were made at angles up to 45 degrees for deuteron energies of 8, 12 and 15 MeV and a proton energy of 15 MeV. The average neutron energy of the (d,n) reactions is shown to

C E Nelson; F O Purser; P Von Behren; H W Newson

1978-01-01

297

Tensor polarization of forward-scattered deuterons in the reactions (p, pd) and (p,. pi. d)  

SciTech Connect

Quadrupole polarization of deuterons from backward pd scattering and from the reaction pp..-->..d..pi../sup +/ at theta/sub c.m./ = 180 /sup 0/ is considered by means of the Craige-Wilkin triangle graph. A reasonable agreement with the experimental data is obtained for pd..-->..pd scattering. A small value of the tensor polarization is predicted for the forward deuterons from the A(p,xd)B nuclear reactions.

Vegh, L.; Kopeliovich, B.Z.; Lapidus, L.I.

1981-02-01

298

Acceleration of polarized deuterons at the synchrophasotron from the source polaris  

SciTech Connect

According to the program of research in the field of relativistic nuclear physics, a cryogenic source of polarized deuterons POLARIS has been tested at the Dubna synchrophasotron. The aim of the tests is to match the source with linac and to accelerate a beam of deuterons. The set-up is described, and results of its operation along with the accelerator are presented. 3 references, 4 figures.

Anishchenko, N.G.; Baldin, A.M.; Beznogikh, Yu.D.; Ershow, V.P.; Fimushkin, V.V.; Monchinsky, V.A.; Pilipenko, Yu.K.; Romanov, Yu.I.; Semenyushkin, I.N.; Shutov, V.B.

1983-01-01

299

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

300

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

301

The S reflector west of Galicia (Spain): Evidence from prestack depth migration for detachment faulting during continental breakup  

NASA Astrophysics Data System (ADS)

The mechanism of continental extension and breakup, and the role of detachment faults in these processes, are currently the subject of intense debate. One possible detachment fault is the S reflector, imaged as an undulating (in time), locally discontinuous reflection on existing seismic profiles west of Iberia. Here we present new images in depth of the four margin-normal profiles across the west Galicia rifted margin, where the S reflector was originally defined and is best imaged. It is shown that faults bounding wedge-shaped units of late synrift sediments, which hence were active during rifting immediately prior to breakup, appear to detach at shallow levels onto the S reflector. S itself appears as a continuous, locally domal feature and does not generally appear offset. The waveform of S is compatible with a reflection from a single interface such as a sharp tectonic boundary. The depth sections show that S was active at 1-3 km below the seafloor during final rifting; S is interpreted as a brittle detachment fault which controlled the final breakup of the continent west of Galicia. Furthermore, the data provide constraints on the sense of shear of S: analogy with detachment terranes, the present, synrift and structural dips of S, and the identification of a breakaway to S imply that S accommodated top-to-the-west shear. Toward the east of the profiles, S becomes more complex, possibly because of different phases of detachment faulting and the development of both incisement and excisement structures. From the geometry of wedge-shaped sedimentary units deposited during faulting above S it also appears that S was active at an angle of 20° or less and hence may be considered a genuine low-angle normal fault.

Reston, T. J.; Krawczyk, C. M.; Klaeschen, D.

1996-04-01

302

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

303

Droplet breakup in accelerating gas flows. Part 2: Secondary atomization  

NASA Technical Reports Server (NTRS)

An experimental investigation to determine the effects of an accelerating gas flow on the atomization characteristics of liquid sprays was conducted. The sprays were produced by impinging two liquid jets. The liquid was molten wax and the gas was nitrogen. The use of molten wax allowed for a quantitative measure of the resulting dropsize distribution. The results of this study, indicate that a significant amount of droplet breakup will occur as a result of the action of the gas on the liquid droplets. Empirical correlations are presented in terms of parameters that were found to affect the mass median dropsize most significantly, the orifice diameter, the liquid injection velocity, and the maximum gas velocity. An empirical correlation for the normalized dropsize distribution is also presented. These correlations are in a form that may be incorporated readily into existing combustion model computer codes for the purpose of calculating rocket engine combustion performance.

Zajac, L. J.

1973-01-01

304

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

305

Gondwanan break-up: legacies of a lost world?  

PubMed

Fierce debate surrounds the history of organisms in the southern hemisphere; did Gondwanan break-up produce ocean barriers that imposed distribution patterns on phylogenies (vicariance)? Or have organisms modified their distributions through trans-oceanic dispersal? Recent advances in biogeographical theory suggest that the current focus on vicariance versus dispersal is too narrow because it ignores 'geodispersal' (i.e. expansion of species into areas when geographical barriers disappear), extinction and sampling errors. Geodispersal produces multiple, conflicting vicariance patterns, and extinction and sampling errors destroy vicariance patterns. This perspective suggests that it is more difficult to detect vicariance than trans-oceanic dispersal and that specialized methods must be applied if an unbiased understanding of southern hemisphere biogeography is to be achieved. PMID:18276035

Upchurch, Paul

2008-04-01

306

Inversion Breakup in Small Rocky Mountain and Alpine Basins  

SciTech Connect

Comparisons are made between the post-sunrise breakup of temperature inversions in two similar closed basins in quite different climate settings, one in the eastern Alps and one in the Rocky Mountains. The small, high-altitude, limestone sinkholes have both experienced extreme temperature minima below -50°C. On undisturbed clear nights, temperature inversions reach to 120 m heights in both sinkholes, but are much stronger in the drier Rocky Mountain basin (24K versus 13K). Inversion destruction takes place 2.6 to 3 hours after sunrise and is accomplished primarily by subsidence warming associated with the removal of air from the base of the inversion by the upslope flows that develop over the sidewalls. Differences in inversion strengths and post-sunrise heating rates are caused by differences in the surface energy budget, with drier soil and a higher sensible heat flux in the Rocky Mountain sinkhole.

Whiteman, Charles D.; Pospichal, Bernhard; Eisenbach, Stefan; Weihs, P.; Clements, Craig B.; Steinacker, Reinhold; Mursch-Radlgruber, Erich; Dorninger, Manfred

2004-08-01

307

X-ray images of an auroral break-up  

NASA Astrophysics Data System (ADS)

Preliminary pictures of electron precipitation regions which produce X rays during an auroral break-up initiation interval are discussed. The X ray pin-hole camera was balloon-borne and recorded the presence of a 20 km spot-like precipitation characterized by a steep energy spectrum. An intense acceleration succeeded the spot event, indicating intensification of the harder component, and displaying behavior similar to that of particle distributions observed on the equator during dispersionless injection events. The parent distributions were detected at geosynchronous altitudes during substorm initiation. Further observations were made of small scale structures, with typical plasma-scale lengths, e.g., a 15 km circle of 10 keV protons.

Mauk, B.; Parks, G. K.

308

Intracratonic basin subsidence: a legacy of continental break-up?  

NASA Astrophysics Data System (ADS)

Intracratonic basins are enigmatic, large, and very long-lived sedimentary basins that exits across all the continental landmasses. After formation the subsidence history continues for hundreds of millions of years, providing a potential archive of change in climate and mantle dynamics. Subsidence within these basins initiates during periods of break-up and dispersal of super-continental assemblies. The long-lived subsidence history then contains episodic periods of uplift and subsidence at intervals of 20 to 50 Myr. We propose that intracontinental basins are formed by extension of the lithosphere, related to continental break-up. The subsequent episodic subsidence is driven by the lateral density contrast at the transition from oceanic to continental lithosphere at the passive margin. Continental lithosphere is melt depleted, buoyant and thick. It will resist convective breakdown into the asthenosphere below, but will be prone to lateral flow due to horizontal density contrasts. Changes in lithosphere thickness at the transition between continent and ocean will nucleate convection cells. Using a numerical model of viscous upper mantle flow we show that stability or instability of the continental lithosphere at a passive margin is a function of the lithospheric rheology and composition. In model simulations, a continental lithosphere thought typical of the Phanerozoic continental platform experiences a topographic fluctuations due to an evolving array of convection cells in the mantle. The timing and magnitude of predicted changes in topography are similar to those observed at the eastern North American margin and the Congo Basin in Africa. The open question is if these small-scale instabilities will eventually lead to the onset of subduction and the destruction of the margin.

Armitage, John; Lucazeau, Francis; Jaupart, Claude

2013-04-01

309

Deuteron energy of 15 MK in ultra-dense deuterium without plasma formation: Temperature of the interior of the Sun  

Microsoft Academic Search

Deuterons are released with kinetic energy up to 630 eV from ultra-dense deuterium as shown previously, by Coulomb explosions initiated by ns laser pulses at ?1011 Wcm?2. With higher laser intensity at 1014 Wcm?2, the initial kinetic energy now observed by TOF-MS with variable acceleration energy is up to 1100 eV per deuteron. This indicates ejection of one deuteron by

Patrik U. Andersson; Leif Holmlid

2010-01-01

310

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

311

Break-Up of Three-Frequency KAM Tori: Determination of the Critical Parameters  

NASA Astrophysics Data System (ADS)

With a four-dimensional symplectic map we study numerically the break-up of three-frequency Kolmogorov-Arnold-Moser (KAM) tori. The locations and stabilities of a sequence of periodic orbits, whose winding numbers approach the irrational winding number of the KAM torus, are examined. The break-up of quadratic frequency tori is characterized as the exponential growth of the residue means of the convergent periodic orbits. Critical parameters of the break-up of tori with different winding numbers are calculated, which show that the spiral mean torus is the most robust one in our model.

Zhou, Ji-Lin; Bam-Bi, HU; Sun, Yi-Sui

2001-06-01

312

Neutron Halo Structure at the Limit of Stability Probed by Breakup Reactions  

NASA Astrophysics Data System (ADS)

Atomic nuclei along the neutron drip line are investigated experimentally by breakup reactions of the rare isotope beams. Such exotic nuclei often show the neutron halo structure, which is the main focus of this paper. Characteristic features of the Coulomb and nuclear breakup at intermediate to high incident energies are described. Then, recent experimental results on halo nuclei, mainly on 31Ne, obtained at the new-generation RI-beam facility, RIBF (RI Beam factory) at RIKEN, are presented. Perspectives for the breakup experiments using the new facility SAMURAI at RIBF ara also discussed.

Nakamura, Takashi

2013-08-01

313

The mode of lithosphere deformation leading to continental breakup and sea-floor spreading initiation  

NASA Astrophysics Data System (ADS)

We investigate two contrasting modes of continental lithosphere thinning leading to continental breakup and sea-floor spreading initiation; lithosphere thinning by pure-shear and by buoyancy assisted upwelling divergent flow. Mantle exhumation at rifted continental margins requires that rupture of continental crust and the unroofing of mantle occur before the start of significant melt production. The relative timing of the onset of ocean ridge melt production is sensitive not only to extension rate, mantle temperature and mantle depletion but also the deformation mode of continental lithosphere thinning leading to continental breakup. Two end-member modes of continental lithosphere thinning deformation have been examined: depth-uniform (pure-shear) lithosphere stretching and thinning, and lithosphere thinning by upwelling divergent flow. Horizontal tensile plate forces provide the driving force for the pure-shear deformation. Upwelling divergent flow is assumed to be driven by a combination of horizontal plate boundary forces and thermal and melt buoyancy initiated by pure-shear lithosphere stretching, and predicts a simple transition from pre-breakup lithosphere thinning to sea-floor spreading. For the N. Iberian - N. Newfoundland margins, pure-shear breakup lithosphere thinning model predicts that the onset of melt generation occurs prior to breakup rupture of the continental crust for normal mantle temperature and chemical composition. In contrast the upwelling divergent flow model predicts the onset of melt generation after continental crust rupture leading to ~ 100 km mantle exhumation on each margin. We propose that continental lithosphere thinning leading to continental breakup and sea-floor spreading initiation is achieved by a simultaneous combination of pure-shear and buoyancy driven upwelling divergent flow within continental lithosphere and asthenosphere. The relative importance of these deformation modes is dependent on depth, pre-breakup extension rates and mantle temperature. Beneath 10-15 km depth the dominant mode of continental lithosphere thinning leading to breakup is upwelling divergent flow driven by thermal and melt buoyancy, while for depths shallower than 10-15 km (corresponding to the cooler upper lithosphere) the dominant thinning mode is pure-shear in the form of brittle faulting. While horizontal tensile plate forces provide the driving force for the pure-shear deformation, the buoyancy induced upwelling divergence flow provides the main contribution to continental lithosphere thinning. Pre-breakup continental lithosphere thinning by combined pure shear and buoyancy driven upwelling divergent flow also predicts depth-dependent stretching of continental margin lithosphere, the development of pre-breakup sag basins with a paucity of pre-breakup brittle deformation and a simple transition from pre-breakup lithosphere thinning to sea-floor spreading.

Kusznir, N. J.; Fletcher, R. J.; Manatschal, G.

2009-04-01

314

Relativistic nuclear corrections to the spin structure function of the deuteron in the light-cone variables  

SciTech Connect

The relativistic deuteron has been considered in the light-cone formalism as a system of two strongly interacting nucleons (two-nucleon approximation). The technique for the calculation of the average helicity of the proton in the deuteron has been considered in the light-cone variables. A receipt has been pro-posed for the consistent calculation of relativistic nuclear corrections to the average helicity of the proton in the deuteron and to the spin structure function of the deuteron g{sub 1}{sup D}. Relativistic-correction-induced change in the Bjorken sum rule has been discussed.

Pavlov, F. F., E-mail: f.pavlov@tuexph.stu.neva.ru [St. Petersburg State Polytechnic University (Russian Federation)

2012-06-15

315

The Precorneal Tear Film: Breakup Time and Location in Normal Subjects.  

National Technical Information Service (NTIS)

Tear film breakup time (BUT) and location were determined in 100 young men. BUT ranged from 10 seconds to over 60 seconds. The desiccated locations were randomly distributed over the entire corneal surface and appeared most often temporally or inferiorly ...

R. H. Rengstorff

1974-01-01

316

Break-up of droplets in a concentrated emulsion flowing through a narrow constriction.  

PubMed

This paper describes the break-up of droplets in a concentrated emulsion during its flow as a 2D monolayer in a microchannel consisting of a narrow constriction. Analysis of the behavior of a large number of drops (N > 4000) shows that the number of break-ups increases with increasing flow rate, entrance angle to the constriction, and size of the drops relative to the width of the constriction. As single drops do not break at the highest flow rate used in the system, break-ups arise primarily from droplet-droplet interactions. Analysis of droplet properties at a high temporal resolution of 10 microseconds makes it possible to relate droplet deformation with droplet break-up probability. Similar to previous studies on single drops, no break-up is observed below a set of critical flow rates and droplet deformations. Unlike previous studies, however, not all drops undergo break-up above the critical values. Instead, the probability of droplet break-up increases with flow rate and the deformation of the drops. The probabilistic nature of the break-up process arises from the stochastic variations in the packing configuration of the drops as they enter the constriction. Local break-up dynamics involves two primary drops. A close look at the interactions between the pair of drops reveals that the competing time scales of droplet rearrangement relative to the relaxation of the opposing drop govern whether break-up occurs or not. Practically, these results can be used to calculate the maximum throughput of the serial interrogation process often employed in droplet microfluidics. For 40 pL-drops, the highest throughput with less than 1% droplet break-up was measured to be approximately 7000 drops per second. In addition, the results presented are useful for understanding the behavior of concentrated emulsions in applications such as mobility control in enhanced oil recovery, and for extrapolating critical parameters such as injection rates to ensure the stability of the fluids going through small pore throats. PMID:24651830

Rosenfeld, Liat; Fan, Lin; Chen, Yunhan; Swoboda, Ryan; Tang, Sindy K Y

2014-01-21

317

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

NASA Technical Reports Server (NTRS)

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

Salama, Ahmed; Ling, Lisa; McRonald, Angus

2005-01-01

318

A generalization of the Numerov method for solution of Nd breakup problem in configuration space  

Microsoft Academic Search

A new computational method for solving the configuration space Faddeev equations for three nucleon system has been developed. This method is based on the spline-decomposition in the angular variable and a generalization of the Numerov method for the hyperradius. The s-wave calculations of the inelasticity and phase-shift, as well as breakup amplitudes for n-d and p-d breakup scattering for lab

Vladimir Suslov; Branislav Vlahovic

2004-01-01

319

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

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

320

Breakup channels for {sup 12}C triple-{alpha} continuum states  

SciTech Connect

The triple-{alpha}-particle breakup of states in the triple-{alpha} continuum of {sup 12}C has been investigated by way of coincident detection of all three {alpha} particles of the breakup. The states have been fed in the {beta} decay of {sup 12}N and {sup 12}B, and the {alpha} particles measured using a setup that covers all of the triple-{alpha} phase space. Contributions from the breakup through the {sup 8}Be(0{sup +}) ground state as well as other channels--interpreted as breakup through excited energies in {sup 8}Be--have been identified. Spins and parities of {sup 12}C triple-{alpha} continuum states are deduced from the measured phase-space distributions for breakup through {sup 8}Be above the ground state by comparison to a fully symmetrized sequential R-matrix description of the breakup. At around 10 MeV in {sup 12}C, the breakup is found to be dominated by 0{sup +} strength breaking up through the ghost of the {sup 8}Be(0{sup +}) ground state with L=0 angular momentum between the first emitted {alpha} particle and the intermediate {sup 8}Be nucleus. For {sup 12}C energies above the 12.7 MeV 1{sup +} state, however, L=2 breakup of a {sup 12}C 2{sup +} state through the {sup 8}Be(2{sup +}) excited state dominates. Furthermore, the possibility of a 2{sup +} excited state in the 9-12 MeV region of {sup 12}C is investigated.

Diget, C. A. [Department of Physics, University of York, York, YO10 5DD (United Kingdom); Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus (Denmark); Barker, F. C. [Department of Theoretical Physics, Research School of Physical Sciences and Engineering, Australian National University, Canberra ACT 0200 (Australia); Borge, M. J. G.; Boutami, R.; Tengblad, O. [Instituto Estructura de la Materia, CSIC, E-28006 Madrid (Spain); Dendooven, P. [Kernfysisch Versneller Institut, University of Groningen, Zernikelaan 25, 9747 AA Groningen (Netherlands); Eronen, T.; Jokinen, A.; Kankainen, A.; Moore, I.; Nieminen, A.; Penttilae, H.; Rinta-Antila, S.; Wang, Y.; Aeystoe, J. [Department of Physics, University of Jyvaeskylae, FIN-40014 Jyvaeskylae (Finland); Fox, S. P.; Fulton, B. R. [Department of Physics, University of York, York, YO10 5DD (United Kingdom); Fynbo, H. O. U.; Hyldegaard, S.; Jeppesen, H. B. [Department of Physics and Astronomy, University of Aarhus, DK-8000 Aarhus (Denmark)] (and others)

2009-09-15

321

Theoretical and Empirical Analysis of the Average Cross-sectional Areas of Breakup Fragments  

Microsoft Academic Search

This paper will compare two different approaches to calculate the average cross-sectional ar-eas of breakup fragments. The first one is described in the NASA standard breakup model 1998 revision. This approach visually classifies fragments into several shapes, and then applies formulae developed for each shape to calculate the average cross-sectional area. The second ap-proach was developed jointly by the Kyushu

Toshiya Hanada; Jer-Chyi Liou

2010-01-01

322

A CFD comparative study of bubble break-up models in a turbulent multiphase jet  

Microsoft Academic Search

In this paper several bubble break-up models are compared. They have been implemented in the CFX-4.4 fluid dynamic commercial code, which uses the population balance equations for describing liquid\\/gas multi-phase flows. The models have been assessed against published experimental data, obtained for air bubble break-up within a turbulent water jet. The model of Martínez-Bazán, based on purely kinematics arguments, has

J. M. Martín-Valdepeñas; M. A. Jiménez; R. Barbero; F. Martín-Fuertes

2007-01-01

323

Light ion source for proton/deuteron production at CEA Saclay for the Spiral2 project  

NASA Astrophysics Data System (ADS)

The production of rare radioactive ion beam (RIB) far from the valley of stability is one of the final purposes of the Spiral2 facility in Caen. The RIB will be produced by impinging a deuteron beam onto a carbon sample to produce a high neutron flux, which will interact with a uranium target. The primary deuteron beam is produced by an ion source based on ECR plasma generation. The deuteron source and the low energy beam transport (LEBT) has been assembled and tested at CEA Saclay. Diagnostics from other laboratories were implemented on the LEBT in order to characterize the deuteron beam produced and compare it to the initial simulations. The ion source has been based on a SILHI-type source, which has demonstrated good performances in pulsed and continuous mode, and also a very good reliability on long term operation. The 5 mA of deuteron beam required at the RFQ entrance is extracted from the plasma source at the energy of 40 kV. After a brief description of the experimental set-up, this article reports on the first beam characterization experiments.

Tuske, O.; Adroit, G.; Delferrière, O.; Denis, J.-F.; Gauthier, Y.; Girardot, P.; Gobin, R.; Harrault, F.; Graehling, P.; Guiho, P.; Hosselet, J.; Maazouzi, C.; Sauce, Y.; Uriot, D.; Vacher, T.; Van Hille, C.

2012-02-01

324

Deuteron formation in expanding nuclear matter from a strong coupling BCS approach  

SciTech Connect

The process of deuteron formation in intermediate heavy ion reactions is approached within the strong coupling BCS theory assuming that the final stage of the reaction can be described as an adiabatic expansion of a piece of nuclear matter. Since the gap equation in the {sup 3}{ital S}{sub 1}-{sup 3}{ital D}{sub 1} channel goes over into the deuteron Schroedinger equation in the low density limit, a smooth transition from the superfluid Cooper pair phase to a Bose deuteron gas is found. For a fixed entropy ranging from 0.5 to 2 units per particle the deuteron fraction, the chemical potential and temperature are reported as a function of density. For densities down to {rho}=0.1 fm{sup {minus}3} and lower, the deuteron-to-nucleon ratio rapidly increases from a density threshold strongly depending on the entropy. Decreasing further the density this ratio tends logarithmically to one. The possible relevance of these results for heavy ion collisions and the shortcomings of the present approach are briefly discussed.

Baldo, M.; Lombardo, U.; Schuck, P. [INFN, Sezione di Catania, 57 Corso Italia, I-95129 Catania (Italy)] [INFN, Sezione di Catania, 57 Corso Italia, I-95129 Catania (Italy); [Dipartimento di Fisica and INFN, 57 Corso Italia, I-95129 Catania (Italy); [CNRS-IN2P3 Universite Joseph Fourier, Institute des Sciences Nucleaires, 53 Av. des Martyrs, F38026 Grenoble Cedex (France)

1995-08-01

325

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

326

Curious Fluid Flows: From Complex Fluid Breakup to Helium Wetting  

NASA Astrophysics Data System (ADS)

This work encompasses three projects; pinch-off dynamics in non-Newtonian fluids; helium wetting on alkali metals; and the investigation of quartz tuning forks as cryogenic pressure transducers. Chapter 1 discusses the breakup of a non-Newtonian yield stress fluid bridge. We measured the minimum neck radius, hmin, as a function of time and fit it to a power law with exponent n 1. We then compare n1 to exponent n2, obtained from a rotational rheometer using a Herschel-Bulkley model. We confirm n1=n2 for the widest variety of non-Newtonian fluids to date. When these fluids are diluted with a Newtonian fluid n1 does not equal n2. No current models predict that behavior, identifying a new class of fluid breakup. Chapter 2 presents the first chemical potential-temperature phase diagram of helium on lithium, sodium and gold, using a novel pressure measurement system. The growth and superfluid transition of a helium film on these substrates is measured via an oscillator for isotherms (fixed temperature, varying amount of helium gas), and quenches (fixed amount of helium gas, varying temperature). The chemical potential-temperature plot is similar for gold, lithium and sodium despite the large difference in the substrate binding energies. No signs of a 2-D liquid-vapor transition were seen. Chapter 3 discusses the creation of a 32.768 kHz quartz tuning fork in situ pressure transducer. Tuning forks are used to measure pressure at room temperature, but no work addresses their potential as cryogenic pressure transducers. We mapped out the behavior of a tuning fork as a function of pressure at 298, 7.0, 2.5, 1.6, 1.0 and 0.7 K by measuring the quality factor. The fork is sensitive to pressures above 0.1 mTorr, limiting its use as a pressure gauge at 0.6 K and below. The experimental curves were compared to a theoretical Q(P, T) function that was refined using the 298 K data. At cryogenic temperatures the formula breaks down in the viscous region and becomes inaccurate. The qualitative shape of the theory, but not its quantitative values, matches the data. The discrepancy between the experimental and theoretical Q values appears to be due to unaccounted for dissipation.

Huisman, Fawn Mitsu

327

The importance of momentum transfer in collision-induced breakups in low Earth orbit  

NASA Technical Reports Server (NTRS)

Although there is adequate information on larger objects in low Earth orbit, specifically those objects larger than about 10 cm in diameter, there is little direct information on objects from this size down to 1 mm. Yet, this is the sized regime where objects acting as projectiles represent the ability to seriously damage or destroy a functioning spacecraft if they collide with it. The observed consequences of known collisional breakups in orbit indicates no significant momentum transfer in the resulting debris cloud. The position taken in this paper is that this is an observational selection effect: what is seen in these events is an explosion-like breakup of the target structure arising from shock waves introduced into the structure by the collision, but one that occurs significantly after the collision processes are completed; the collision cloud, in which there is momentum transfer, consists of small, unobserved fragments. Preliminary computations of the contribution of one known collisional breakup, Solwind at 500 km in 1985, and Cosmos 1275 in 1981, assume no momentum transfer on breakup and indicate that these two events are the dominant contributors to the current millimeter and centimeter population. A different story would emerge if momentum transfer was taken into account. The topics covered include: (1) observation of on-orbit collisional breakups; (2) a model for momentum transfer; and (3) velocity space representation of breakup clouds.

Reynolds, Robert C.; Lillie, Brian J.

1991-01-01

328

Deuteron NMR investigations of glass and phase transitions in (KI)1-x(ND4I)x mixed crystals  

Microsoft Academic Search

Powdered potassium ammonium iodide mixed crystals with ammonium concentrations of 20% and 70% have been studied using deuteron NMR techniques. For the less doped sample the deuteron line starts to broaden and the spin-lattice relaxation time T1 becomes nonexponential below about 20 K. These observations indicate the breakdown of ergodicity and the onset of orientational glass freezing. At the lowest

M. Winterlich; A. Titze; G. Hinze; R. Böhmer

1998-01-01

329

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

330

Deuteron cross section evaluation for safety and radioprotection calculations of IFMIF/EVEDA accelerator prototype  

NASA Astrophysics Data System (ADS)

In the frame of IFMIF/EVEDA activities, a prototype accelerator delivering a high power deuteron beam is under construction in Japan. Interaction of these deuterons with matter will generate high levels of neutrons and induced activation, whose predicted yields depend strongly on the models used to calculate the different cross sections. A benchmark test was performed to validate these data for deuteron energies up to 20 MeV and to define a reasonable methodology for calculating the cross sections needed for EVEDA. Calculations were performed using the nuclear models included in MCNPX and PHITS, and the dedicated nuclear model code TALYS. Although the results obtained using TALYS (global parameters) or Monte Carlo codes disagree with experimental values, a solution is proposed to compute cross sections that are a good fit to experimental data. A consistent computational procedure is also suggested to improve both transport simulations/prompt dose and activation/residual dose calculations required for EVEDA.

Blideanu, Valentin; García, Mauricio; Joyer, Philippe; López, Daniel; Mayoral, Alicia; Ogando, Francisco; Ortíz, Félix; Sanz, Javier; Sauvan, Patrick

2011-10-01

331

Nuclear fission cross sections induced by deuterons of 4 GeV  

NASA Astrophysics Data System (ADS)

Nuclear fission cross sections induced by deuterons of 4 GeV were measured by the solid state nuclear track detectors technique. The experiments were carried out at the Nuclotron accelerator of the Joint Institute for Nuclear Research (JINR) (LHE), Dubna. Heavy targets such as 232Th, 235U, and 238U as well as 209Bi and 197Au were irradiated by 1011 deuterons. The cross sections for radioactive targets were estimated as ?f=1153 (±198), 1666 (±430), 1453 (±350) mb for 232Th, 235U, 238U, while for 209Bi and 197Au as ?f=206 (±46), 92 (±23), respectively. The comparison of these results with proton-induced fission systematics shows higher fission cross sections when deuterons are used as projectiles. The part of the reaction cross section that fission acquires is found to be much higher for actinide targets than for targets of lower atomic numbers.

Stoulos, S.; Westmeier, W.; Hashemi-Nezhad, R.; Fragopoulou, M.; Lagoyannis, A.; Zamani, M.

2012-02-01

332

Variability of the fluvial thermal process during ice breakups of the Lena river (Siberia)  

NASA Astrophysics Data System (ADS)

A 4-years observation program was initiated to quantify the variability of the fluvial thermal erosion during the ice breakups of the Lena River in Central Siberia. Parameters affecting fluvial thermal erosion have been collected in the middle valley near Yakutsk city where active fluvial thermal erosion on frozen islands has been recorded. The heads of islands undergo strong erosion with mean values of 12 m per year and maximal values reaching 40 m. The careful analysis of the annual data shows a high variability of the erosion rate, mostly due to the variability of the water stream temperature and to the duration and timing of the flood season. A laboratory simulation was proposed to quantify the potential impact of the recent global warming, by means of an increase of the water stream temperature. A hydraulic channel in a cold chamber simulate the ground thawing produced by heat transfer from the flow of water through the frozen ground; followed by mechanical transport of the thawed sediments. The measured increase up to 2°C of the water stream temperature could alone multiply the erosion rate by 16% and explains the acceleration of the mobility of fluvial islands on the Lena river.

Costard, Francois; Gautier, Emmanuele; Fedorov, Alexander; Konstantinov, Pacha; Dupeyrat, Laure

2013-04-01

333

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

334

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

335

Debris collision hazard from breakups in the geosynchronous ring  

NASA Astrophysics Data System (ADS)

This paper presents a study of the short-term collision risk posed to the resident Earth-orbiting population by fragments generated in hypothetical explosions in the geosynchronous ring. Debris clouds resulting from such explosions contain constrictions, which are regions of high fragment density caused by the Earth's central gravitational attraction. The highest density constriction, the pinch point, is almost fixed inertially and occurs at the breakup point. Hence most of the resident geosynchronous population flies near it. In this study, the computer programs IMPACT and DEBRIS were used to assess collision risk. Program IMPACT was used to model the explosions, and program DEBRIS was used to perform short-term debris cloud propagation and compute collision risk. The four cases considered are all based on the explosion of a generic liquid apogee kick stage which has never happened in the geosynchronous ring. The satellites for which collision risk was assessed were taken from an August 1995 update of the USSPACECOM Satellite Catalog. It was found that short-term collision risk was low, even though the entire geosynchronous population flies near the pinch point. This occurs because the fragments are spread over very large volumes in geosynchronous orbit. However, approximate extrapolation of these results indicates an increased collision risk in the intermediate time frame of several months to a year. Due to the lack of a cleansing perturbation in the geostationary region, collisions are statistically likely to occur.

Kamprath, Michael F.; Jenkin, Alan B.

1998-11-01

336

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

337

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

338

Deuteron energy of 15 MK in ultra-dense deuterium without plasma formation: Temperature of the interior of the Sun  

NASA Astrophysics Data System (ADS)

Deuterons are released with kinetic energy up to 630 eV from ultra-dense deuterium as shown previously, by Coulomb explosions initiated by ns laser pulses at ?10 W cm. With higher laser intensity at <10 W cm, the initial kinetic energy now observed by TOF-MS with variable acceleration energy is up to 1100 eV per deuteron. This indicates ejection of one deuteron by Coulomb repulsion from two stationary charges in the material. It proves a full kinetic energy release of 1260 eV or a deuteron temperature of 15 MK, similar to the temperature in the interior of the Sun. Plasma processes are excluded by the sharp TOF peaks observed and by the slow signal variation with laser intensity. Deuterons with even higher energy from multiple charge repulsion are probably detected. D + D fusion processes are expected to exist in the ultra-dense phase without plasma formation.

Andersson, Patrik U.; Holmlid, Leif

2010-06-01

339

Predominance of transfer in triggering breakup in sub-barrier reactions of 6,7Li with 144Sm, 207,208Pb, and 209Bi  

NASA Astrophysics Data System (ADS)

Coincidence measurements of breakup fragments were carried out for the 7Li+144Sm and 6,7Li+207,208Pb,209Bi reactions at sub-barrier energies. Breakup modes in reactions of 6,7Li were identified through the reaction Q values, and the time-scales of each process inferred through the relative energy of the breakup fragments. Breakup was found to be predominantly triggered by nucleon transfer, with p pickup leading to ?+? coincidences being the preferred breakup mode for 7Li, and n stripping leading to ?+p for 6Li. Breakup triggered by 2n stripping was also found to be prominent in the 7Li+144Sm reaction. The breakup yields were separated into prompt and delayed components based on the relative energies of the breakup fragments. This enables the identification of breakup process important in the suppression of complete fusion of 6,7Li at above-barrier energies.

Luong, D. H.; Dasgupta, M.; Hinde, D. J.; du Rietz, R.; Rafiei, R.; Lin, C. J.; Evers, M.; Diaz-Torres, A.

2013-09-01

340

Coherent {pi}{sup 0}-photoproduction on the deuteron including polarization observables  

SciTech Connect

Coherent {pi}{sup 0}-photoproduction on the deuteron including polarization effects in the energy region from {pi}-threshold up to 1 GeV is studied using an enhanced elementary pion photo-production operator on the free nucleon and a realistic NN potential model for the deuteron wave function. Results for double polarization observables are predicted for which the sensitivity to various models for the elementary pion photoproduction amplitude is investigated. We find considerable dependence of the results on the elementary amplitude. In addition, results for differential cross section are predicted and compared with the experimental data from TAPS and a satisfactory agreement was found.

Darwish, E. M. [Applied Physics Department, Faculty of Applied Science, Taibah University (Saudi Arabia); Physics Department, Faculty of Science, Sohag University, Sohag 82524 (Egypt); Akopov, N. [Yerevan Physics Institute, Br. Alikhanian 2, 0036 Yerevan (Armenia); El-Zohry, M. [Yerevan State University, A. Manoogian 1, 0025 Yerevan (Armenia)

2011-10-27

341

Prospect for observation of polarization in electron-deuteron elastic scattering at high momentum transfer  

SciTech Connect

A measurement of the charge and quadrupole form factors of the deuteron would address the most fundamental questions in nuclear physics: validity of perturbative QCD at relatively low momentum transfer, effect of isoscalar meson-exchange currents, and the deuteron structure at short range. Polarization methods will be required in order to provide the separation of these form factors. We propose that the high current of electrons in a storage ring be employed in order to scatter electrons from a gaseous, tensor-polarized, deuterium target.

Holt, R.J.; Green, M.C.; Young, L.; Kowalczyk, R.S.; Geesaman, D.F.; Zeidman, B.; Goodman, L.S.; Napolitano, J.

1985-01-01

342

Measurement of all Deuteron Analyzing Powers for Elastic Scattering at 294 MeV/Nucleon  

NASA Astrophysics Data System (ADS)

We have measured all deuteron analyzing powers for deuteron-proton elastic scattering at 294 MeV/nucleon in order to study the properties of three nucleon forces (3 NFs). Measurement was made at in an angular range of . Obtained data were compared with Faddeev calculations with and without the 3 NFs. At all the data have general agreement with the calculations, while the measured data at are not explained by any theoretical calculations. These results were consistent with those at 250 MeV/nucleon.

Wada, Y.; Sekiguchi, K.; Miyazaki, J.; Taguchi, T.; Dozono, M.; Gebauer, U.; Kawase, S.; Kubota, Y.; Lee, C. S.; Maeda, Y.; Mashiko, T.; Miki, K.; Sakaguchi, S.; Sakai, H.; Sakamoto, N.; Sasano, M.; Shimizu, Y.; Takahashi, K.; Tang, R.; Uesaka, T.; Wakasa, T.; Yako, K.

2013-08-01

343

Measurements of the Deuteron Elastic Structure Function A(Q{sup 2}) for 0.7  

SciTech Connect

The deuteron elastic structure function A(Q{sup 2}) has been extracted in the range 0.7 < or = Q{sup 2} < or = 6.0 (GeV/c){sup 2} from cross section measurements of elastic electron-deuteron scattering in coincidence using the Hall A Facility of Jefferson Laboratory. 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.

L. C. Alexa; B. D. Anderson; K. A. Aniol; K. Arundell; L. Auerbach; F. T. Baker; J. Berthot; P. Y. Bertin; W. Bertozzi; L. Bimbot; W. U. Boeglin; E. J. Brash; V. Breton; H. Breuer; E. Burtin; J. R. Calarco; L. S. Cardman; C. Cavata; C.-C. Chang; J.-P. Chen; E. Chudakov; E. Cisbani; D. S. Dale; N. Degrande; R. De Leo; A. Deur; N. d'Hose; B. Diederich; J. J. Domingo; M. B. Epstein; L. A. Ewell; J. M. Finn; K. G. Fissum; H. Fonvieille; B. Frois; S. Frullani; H. Gao; J. Gao; F. Garibaldi; A. Gasparian,; S. Gilad; R. Gilman; A. Glamazdin; C. Glashausser; J. Gomez; V. Gorbenko; J.-O. Hansen; R. Holmes; M. Holtrop; C. Howell; G. M. Huber; C. Hyde-Wright; M. Iodice; C. W. de Jager; S. Jaminion; J. Jardillier; M. K. Jones; C. Jutier,; W. Kahl; S. Kato; A. T. Katramatou; J. J. Kelly; S. Kerhoas; A. Ketikyan; M. Khayat; K. Kino; L. H. Kramer; K. S. Kumar; G. Kumbartzki; M. Kuss; G. Lavessiere; A. Leone; J. J. LeRose; M. Liang; R. A. Lindgren; N. Liyanage; G. J. Lolos; R. W. Lourie; R. Madey,; K. Maeda; S. Malov; D. M. Manley; D. J. Margaziotis; P. Markowitz; J. Marroncle; J. Martino; C. J. Martoff; K. McCormick; J. McIntyre; R. L. J. van der Meer; S. Mehrabyan; Z.-E. Meziani; R. Michaels; G. W. Miller; J. Y. Mougey; S. K. Nanda; D. Neyret; E. A. J. M. Offermann; Z. Papandreou; C. F. Perdrisat; R. Perrino; G. G. Petratos; S. Platchkov; R. Pomatsalyuk; D. L. Prout; V. A. Punjabi; T. Pussieux; G. Quemener; R. D. Ransome; O. Ravel; Y. Roblin; D. Rowntree; G. Rutledge; P. M. Rutt; A. Saha; T. Saito; A. J. Sarty; A. Serdarevic,; T. Smith; K. Soldi; P. Sorokin; P. A. Souder; R. Suleiman; J. A. Templon; T. Terasawa; L. Todor; H. Tsubota; H. Ueno; P. E. Ulmer; G. M. Urciuoli; L. Van Hoorebeke; P. Vernin; B. Vlahovic; H. Voskanyan; J. W. Watson; L. B. Weinstein; K. Wijesooriya; R. Wilson; B. B. Wojtsekhowski; D. G. Zainea; W-M. Zhang; J. Zhao; Z.-L. Zhou

1999-02-15

344

A hydrocarbon fluid-based deuteron ion source for neutron generators  

NASA Astrophysics Data System (ADS)

A deuteron ion source based on a spark discharge between electrodes coated with a deuterated hydrocarbon fluid is investigated. In the prototypic example studied here ion currents extracted from the source were on the order of 0.5 A with a pulse duration of approximately 10 ?s. Operation in a laboratory neutron generator provided a neutron yield of ˜105 neutrons/pulse with the deuterium-deuterium fusion reaction at a deuteron ion energy of 65 keV. This approach to ion sources for neutron generators has the potential to provide a compact, long-lived, high-output neutron generator for homeland security applications.

Schwoebel, P. R.

2012-10-01

345

Deuteron magnetic resonance and hydrogen bond network of ammonium trihydrogen selenite  

NASA Astrophysics Data System (ADS)

The DMR spectra of single-crystal ND 4D 3(SeO 3) 2 have been studied. The principal values and the direction cosines of the field-gradient tensor of deuterons located on three nonequivalent O · · · O hydrogen bonds have been determined. The lengths of hydrogen bonds have been calculated from {eQq}/{h} values; the deuterons have been located on hydrogen bonds. The comparison with the DMR data of isomorphous compound RbD 3(SeO 3) 2 was made; the influence of N?H · · · O hydrogen bonds on the structural parameters O · · · O hydrogen bonds is discussed.

Vinogradova, I. S.

1981-07-01

346

Kaon photoproduction from the deuteron in a Regge-plus-resonance approach  

NASA Astrophysics Data System (ADS)

We present a Regge-inspired effective-Lagrangian framework for kaon photoproduction from the deuteron. Quasi-free kaon production is investigated using the Regge-plus-resonance (RPR) elementary operator within the relativistic plane-wave impulse approximation. The RPR model was developed to describe photoinduced and electroinduced charged-kaon production off protons. We show how this elementary operator can be transformed in order to account for the production of neutral kaons from both protons and neutrons. The model results for kaon photoproduction from the deuteron compare favourably to the H2(?,K)YN data published to date.

Vancraeyveld, P.; De Cruz, L.; Ryckebusch, J.; Vrancx, T.

2013-01-01

347

Parallel momentum distribution of ¹°Be fragments from the break-up of ¹¹Be  

Microsoft Academic Search

The momentum distribution of ¹°Be fragments following direct break-up, ¹¹Beâ ¹°Be + n, is expected to reflect the momentum distribution of the valence neutron, and via the uncertainty principle, its density distribution in ¹¹Be. The one neutron break-up of ¹¹Be is a two body problem and is less complicated than the three body break-up of ¹¹Li where the neutrons may

J. H. Kelley; S. M. Autsin; R. A. Kryger

1993-01-01

348

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

NASA Astrophysics Data System (ADS)

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, ?˜CR?(?CRR/?)?0.40 , which is independent of surfactant used, solution viscosity, and bubble volume fraction (varied between 92 and 98 %). Here ?CR is the dimensional shear stress, above which a bubble with radius R and surface tension ? would break in sheared foam. The value of the critical stress experimentally found by us ?˜CR?0.40 , is about two orders of magnitude lower than the critical stress for breakup of single bubbles in sheared Newtonian liquids, ?˜CR?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% ???95% to study drop breakup in concentrated emulsions. Qualitatively similar behavior was observed to that of foams, with the critical dimensionless stress for drop breakup being lower, ?˜CR?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.

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

2008-11-01

349

Dependence of Mantle Exhumation at Rifted Continental Margins on the Deformation Mode of Breakup Lithosphere Thinning  

NASA Astrophysics Data System (ADS)

Mantle exhumation at rifted continental margins requires that rupture of continental crust and the unroofing of mantle occurs before the start of significant melt production. The relative timing of the onset of ocean ridge melt production is sensitive not only to extension rate, mantle temperature and mantle depletion but also the deformation mode of continental lithosphere thinning leading to continental breakup. Two end-member modes of continental lithosphere thinning deformation have been examined: depth-uniform (pure-shear) lithosphere stretching and thinning, and lithosphere thinning by upwelling divergent flow. Horizontal tensile plate forces provide the driving force for the pure-shear deformation. Upwelling divergent flow is assumed to be driven by a combination of horizontal plate boundary forces and thermal and melt buoyancy initiated by pure-shear lithosphere stretching, and predicts a simple transition from pre-breakup lithosphere thinning to sea-floor spreading. For the N. Iberian - N. Newfoundland margins, pure-shear breakup lithosphere thinning model predicts that the onset of melt generation occurs prior to breakup rupture of the continental crust for normal mantle temperature and chemical composition. In contrast the upwelling divergent flow model predicts the onset of melt generation after continental crust rupture leading to ~ 100 km mantle exhumation on each margin. Continental lithosphere thinning leading to continental breakup and sea-floor spreading initiation is most likely achieved by a simultaneous combination of pure-shear and upwelling divergent flow within continental lithosphere and asthenosphere. The relative importance of these deformation modes is dependent on depth, pre-breakup extension rates and mantle temperature. We proposes that beneath 10-15 km depth the dominant mode of continental lithosphere thinning leading to breakup is upwelling divergent flow, while for depths shallower than 10-15 km (corresponding to the cooler upper lithosphere) the dominant thinning mode is pure-shear in the form of brittle faulting.

Kusznir, N. J.; Fletcher, R. J.; Manatschal, G.

2008-12-01

350

Barrier distribution from {sup 9}Be+{sup 208}Pb quasielastic scattering: Breakup effects in the interaction processes  

SciTech Connect

Excitation function of the quasielastic (QEL) scattering at a backward angle was measured for the weakly bound projectile {sup 9}Be, which bombarded a {sup 208}Pb target at near-barrier energies. Barrier distribution was extracted by means of the first derivative of the experimental cross sections with respect to the effective energies. Theoretical fusion barrier distribution has been calculated with the coupled-channels model and compared with the experimental barrier distribution. By this comparison, it is shown that the experimental barrier distribution extracted from QEL scattering is shifted to low energy by 1.5 MeV as compared with the theoretical one. This energy discrepancy between the theoretical prediction and the experimental data indicates the breakup is an important reaction mechanism in the colliding processes of the weakly bound projectile {sup 9}Be on a spherical target {sup 208}Pb.

Jia, H. M.; Lin, C. J.; Zhang, H. Q.; Liu, Z. H.; Yu, N.; Yang, F.; Jia, F.; Xu, X. X.; Wu, Z. D.; Zhang, S. T.; Bai, C. L. [China Institute of Atomic Energy, P. O. Box 275(10), Beijing 102413 (China)

2010-08-15

351

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

352

Semi-inclusive charged-pion electroproduction off protons and deuterons: Cross sections, ratios, and access to the quark-parton model at low energies  

NASA Astrophysics Data System (ADS)

A large set of cross sections for semi-inclusive electroproduction of charged pions (?±) from both proton and deuteron targets was measured. The data are in the deep-inelastic scattering region with invariant mass squared W2>4 GeV2 (up to ?7 GeV2) and range in four-momentum transfer squared 2mechanisms. The x, z, and Pt2 dependences of several ratios (the ratios of favored-unfavored fragmentation functions, charged pion ratios, deuteron-hydrogen and aluminum-deuteron ratios for ?+ and ?-) have been studied. The ratios are found to be in good agreement with expectations based upon a high-energy quark-parton model description. We find the azimuthal dependences to be small, as compared to exclusive pion electroproduction, and consistent with theoretical expectations based on tree-level factorization in terms of transverse-momentum-dependent parton distribution and fragmentation functions. In the context of a simple model, the initial transverse momenta of d quarks are found to be slightly smaller than for u quarks, while the transverse momentum width of the favored fragmentation function is about the same as for the unfavored one, and both fragmentation widths are larger than the quark widths.

Asaturyan, R.; Ent, R.; Mkrtchyan, H.; Navasardyan, T.; Tadevosyan, V.; Adams, G. S.; Ahmidouch, A.; Angelescu, T.; Arrington, J.; Asaturyan, A.; Baker, O. K.; Benmouna, N.; Bertoncini, C.; Blok, H. P.; Boeglin, W. U.; Bosted, P. E.; Breuer, H.; Christy, M. E.; Connell, S. H.; Cui, Y.; Dalton, M. M.; Danagoulian, S.; Day, D.; Dunne, J. A.; Dutta, D.; El Khayari, N.; Fenker, H. C.; Frolov, V. V.; Gan, L.; Gaskell, D.; Hafidi, K.; Hinton, W.; Holt, R. J.; Horn, T.; Huber, G. M.; Hungerford, E.; Jiang, X.; Jones, M.; Joo, K.; Kalantarians, N.; Kelly, J. J.; Keppel, C. E.; Kubarovsky, V.; Li, Y.; Liang, Y.; Mack, D.; Malace, S. P.; Markowitz, P.; McGrath, E.; McKee, P.; Meekins, D. G.; Mkrtchyan, A.; Moziak, B.; Niculescu, G.; Niculescu, I.; Opper, A. K.; Ostapenko, T.; Reimer, P. E.; Reinhold, J.; Roche, J.; Rock, S. E.; Schulte, E.; Segbefia, E.; Smith, C.; Smith, G. R.; Stoler, P.; Tang, L.; Ungaro, M.; Uzzle, A.; Vidakovic, S.; Villano, A.; Vulcan, W. F.; Wang, M.; Warren, G.; Wesselmann, F. R.; Wojtsekhowski, B.; Wood, S. A.; Xu, C.; Yuan, L.; Zheng, X.

2012-01-01

353

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

354

Western Canadian Arctic ringed seal organic contaminant trends in relation to sea ice break-up.  

PubMed

The association between changing sea ice conditions and contaminant exposure to Arctic animals interests Inuvialuit harvesters, communities, and researchers. We examined organochlorine contaminant (OC) concentrations in the blubber of 90 male adult ringed seals (Phoca hispida) sampled from the subsistence harvest in Ulukhaktok (formerly Holman), NT, Canada, just prior to break-up of the sea ice (1993-2008). OC blubber concentrations were assessed with respect to year and sea ice break-up date. HCB and age- and blubber-adjusted concentrations of p,p'-DDT and ?CHB (chlorobornane) significantly decreased over the study period. With respect to the timing of the spring break-up, highly lipophlic OCs, such as p,p'-DDE and PCB 153, were higher during years of early ice clearing (at least 12 days earlier than the mean annual break-up date), whereas no trends were observed for ?, ?, and ? isomers of HCH, trans- and cis-chlordane, oxychlordane, or ?CHB. The higher contaminant concentrations found in earlier break-up years is likely due to earlier and/or increased foraging opportunities. This situation also has potential for enhancing bioaccumulation and biomagnification of contaminants over the long-term if projected changes continue to result in lighter and earlier ice conditions. PMID:22428683

Gaden, A; Ferguson, Steve H; Harwood, L; Melling, H; Alikamik, J; Stern, G A

2012-04-17

355

Production of Source Neutrons by Low Voltage Accelerated Deuterons on Titanium - Tritium Targets  

Microsoft Academic Search

The detailed information on neutron source characteristics is important to meet the demand of research and applications on neutron activation and transport phenomena. Fast monoenergetic neutrons can be produced by two body reactions induced by accelerated particles. In a number of laboratories much progress has been made in producing intense neutron sources based on the Deuteron - Tritium reaction to

Alberto Milocco; Andrej Trkov

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

The A(Q{sup 2}) Deuteron Structure Function from the Jefferson Lab t20 Experiment  

SciTech Connect

Differential cross-sections for electron deuteron elastic scattering were measured in a 4-momentum transfer range between 0.66 and 1.80 (GeV/c)2. This experiment was performed in the Hall C of the Jefferson Laboratory in 1997. The 80 muA electron beam was incident upon a 4.5 cm liquid deuterium target. The scattered electrons were measured in the high momentum spectrometer HMS, in coincidence with recoil deuterons. A specifically designed magnetic spectrometer and the upstream part of the POLDER polarimeter were used to detect the deuterons. A special collimator in HMS ensured a precise knowledge of the solid angle and a complete match between the two spectrometers. From these data, the A(Q) structure function was extracted with typical uncertainties of +- 5 percent. These new data resolve discrepancies between older experiments (in particular between Saclay and SLAC) [ARN75,BOS90,PLA90] and allow a precise comparison with theoretical models of the deuteron electromagnetic structure.

David Pitz

1998-12-01

358

Neutron and high energy deuteron anisotropy investigations in plasma focus device  

NASA Astrophysics Data System (ADS)

The anisotropies of neutron and high energy deuteron emissions from the NX2 plasma focus device [M. V. Roshan et al., Phys. Lett. A 373, 851 (2009)] are studied. The nuclear activation of graphite targets is used to measure the fluences of high energy deuterons in the axial and radial directions. Two bismuth germanate scintillation detectors connected to multichannel analyzer systems are used for the detection of 511 keV gamma rays resulting from positron annihilation in the two targets. In addition, fast neutron activation detectors are employed to measure the axial and radial fluences of fusion neutrons. These detection systems are calibrated using the simulation code MCNPX [L. S. Waters et al., AIP Conf. Proc. 896, 81 (2007)]. Two distinct regimes of neutron and deuteron anisotropies are observed for the NX2 device. For deuterium gas pressures below 10 mbar, the neutron anisotropy increases with increasing pressure, while the overall neutron yield remains low. For gas pressures of 10-14 mbar, the neutron anisotropy is essentially constant, while, with increasing pressure, the neutron yield rises rapidly and the deuteron anisotropy falls.

Roshan, M. V.; Rawat, R. S.; Talebitaher, A.; Lee, P.; Springham, S. V.

2009-05-01

359

Activation Measurements of High Energy Deuterons in the Plasma Focus Device.  

National Technical Information Service (NTIS)

Nuclear activation techniques were used to measure the fluence of high energy deuterons in a plasma focus device having a stored energy of 75 kilojoules at 18 kV. The exp 12 C(d,n) exp 13 N (330 keV threshold) and exp 27 Al(d,p) exp 28 Al reactions were u...

R. L. Gullickson H. L. Sahlin

1975-01-01

360

Neutron and high energy deuteron anisotropy investigations in plasma focus device  

SciTech Connect

The anisotropies of neutron and high energy deuteron emissions from the NX2 plasma focus device [M. V. Roshan et al., Phys. Lett. A 373, 851 (2009)] are studied. The nuclear activation of graphite targets is used to measure the fluences of high energy deuterons in the axial and radial directions. Two bismuth germanate scintillation detectors connected to multichannel analyzer systems are used for the detection of 511 keV gamma rays resulting from positron annihilation in the two targets. In addition, fast neutron activation detectors are employed to measure the axial and radial fluences of fusion neutrons. These detection systems are calibrated using the simulation code MCNPX[L. S. Waters et al., AIP Conf. Proc. 896, 81 (2007)]. Two distinct regimes of neutron and deuteron anisotropies are observed for the NX2 device. For deuterium gas pressures below 10 mbar, the neutron anisotropy increases with increasing pressure, while the overall neutron yield remains low. For gas pressures of 10-14 mbar, the neutron anisotropy is essentially constant, while, with increasing pressure, the neutron yield rises rapidly and the deuteron anisotropy falls.

Roshan, M. V.; Rawat, R. S.; Talebitaher, A.; Lee, P.; Springham, S. V. [National Institute of Education, Nanyang Technological University, 637616 Singapore (Singapore)

2009-05-15

361

T(sub 20) problem and spin observables in pion-deuteron scattering.  

National Technical Information Service (NTIS)

The purpose of the work is the study of various spin observables in the elastic pion-deuteron scattering predicted by the coupled (pi) NN - NN model in comparison with experimental data. The apparent failure in reproducing the tensor polarization T(sub 20...

T. Mizutani B. Saghai C. Fayard G. H. Lamot

1989-01-01

362

Some Convergence Tests on Medium Energy Pion-Deuteron Elastic Scattering Amplitudes.  

National Technical Information Service (NTIS)

With the exact solution of a covariant multiple scattering model for elastic pion deuteron scattering as a standard, the convergence of the multiple scattering series and the sufficiency of the first order and on-shell second order scattering amplitudes a...

A. S. Rinat Y. Starkand

1979-01-01

363

Exchange-current contribution to the pion-deuteron scattering length  

NASA Astrophysics Data System (ADS)

Chiral symmetry, implemented by means of effective lagrangians, is used to evaluate the exchange-current contribution to the pion-deuteron scattering length. It is shown that this approximate ssymmetry is responsible for partial cancellations, yielding an overall contribution of about 10% of the total scattering length. Work supported in part by the Conselho Nacional de Desenvolvimento Cientifico e Tecnológico, Brazil.

Robilotta, M. R.

1980-05-01

364

Spin Resonances for Stored Deuteron Beams in COSY. Vector Polarization. Tracking with Spink.  

National Technical Information Service (NTIS)

Results of measurements of vector and tensor polarization of a deuteron beam in the storage ring COSY have been published by the SPIN(at)COSY collaboration. In this experiment a RF Dipole was used that produced spin flip. The strength of the RFD-induced d...

A. Lehrach A. Luccio

2008-01-01

365

Search for the H dibaryon by {Xi}{sup {minus}} capture on the deuteron  

SciTech Connect

The present status of the H-dibaryon search experiment at Brookhaven (E813) using the formation reaction through {Xi}{sup {minus}} atomic operation on the deuteron, ({Xi}{sup {minus}}, d){sub atom} {yields} H n, is reported with emphasis placed on the analysis of the data collected with the 1992 slow extracted proton beam run.

Iijima, Toru [Kyoto Univ. (Japan). Dept. of Physics; E813 Collaboration

1993-12-31

366

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

367

Momentum distribution of nucleons in the deuteron on the basis of the Moscow potential  

SciTech Connect

Themomentum distribution of nucleons in the deuteron is calculated for the Moscow and Paris nucleon-nucleon potentials. It is shown that the Moscow potential provides a better description of the distribution deduced from data on the reaction d(e, e Prime p)n in the region close to the kinematical region of quasielastic proton knockout.

Neudatchin, V. G. [Moscow State University, Institute of Nuclear Physics (Russian Federation); Khokhlov, N. A. [Komsomolsk-on-Amur State Technical University (Russian Federation)

2013-06-15

368

Study of the Breakup Reaction {sup 8}B{r_arrow}{sup {bold 7}}Be{bold +}{ital p}: Absorption Effects and {ital E{bold 2}} Strength  

SciTech Connect

Distributions of parallel and transverse momenta for {sup 7}Be fragments formed in the breakup of {sup 8}B have been measured at 41A MeV. The {ital p}{sub {parallel}} distributions are narrow (81{plus_minus}4 and 62{plus_minus}3MeV/{ital c} FWHM for Be and Au targets, respectively), comparable to those of neutron halo nuclei. Reaction mechanisms influence the {sup 7}Be momentum distributions, so they do not directly reflect the valence proton momentum wave function. We present reaction models that reproduce the distributions. {copyright} {ital 1996 The American Physical Society.}

Kelley, J.H.; Austin, S.M.; Azhari, A.; Bazin, D.; Brown, J.A.; Esbensen, H.; Fauerbach, M.; Hellstroem, M.; Hirzebruch, S.E.; Kryger, R.A.; Morrissey, D.J.; Pfaff, R.; Powell, C.F.; Ramakrishnan, E.; Sherrill, B.M.; Steiner, M.; Suomijaervi, T.; Thoennessen, M. [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States)] [National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, Michigan 48824 (United States); [Department of Physics and Astronomy, Michigan State University, East Lansing, Michigan 48824 (United States); [Department of Chemistry, Michigan State University, East Lansing, Michigan 48824 (United States); [Physics Division, Argonne National Laboratory, Argonne, Illinois 60439 (United States)

1996-12-01

369

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

370

Effects of earlier sea ice breakup on survival and population size of polar bears in western Hudson Bay  

USGS Publications Warehouse

Some of the most pronounced ecological responses to climatic warming are expected to occur in polar marine regions, where temperature increases have been the greatest and sea ice provides a sensitive mechanism by which climatic conditions affect sympagic (i.e., with ice) species. Population-level effects of climatic change, however, remain difficult to quantify. We used a flexible extension of Cormack-Jolly-Seber capture-recapture models to estimate population size and survival for polar bears (Ursus maritimus), one of the most ice-dependent of Arctic marine mammals. We analyzed data for polar bears captured from 1984 to 2004 along the western coast of Hudson Bay and in the community of Churchill, Manitoba, Canada. The Western Hudson Bay polar bear population declined from 1,194 (95% CI = 1,020-1,368) in 1987 to 935 (95% CI = 794-1,076) in 2004. Total apparent survival of prime-adult polar bears (5-19 yr) was stable for females (0.93; 95% CI = 0.91-0.94) and males (0.90; 95% CI = 0.88-0.91). Survival of juvenile, subadult, and senescent-adult polar bears was correlated with spring sea ice breakup date, which was variable among years and occurred approximately 3 weeks earlier in 2004 than in 1984. We propose that this correlation provides evidence for a causal association between earlier sea ice breakup (due to climatic warming) and decreased polar bear survival. It may also explain why Churchill, like other communities along the western coast of Hudson Bay, has experienced an increase in human-polar bear interactions in recent years. Earlier sea ice breakup may have resulted in a larger number of nutritionally stressed polar bears, which are encroaching on human habitations in search of supplemental food. Because western Hudson Bay is near the southern limit of the species' range, our findings may foreshadow the demographic responses and management challenges that more northerly polar bear populations will experience if climatic warming in the Arctic continues as projected.

Regehr, E. V.; Lunn, N. J.; Amstrup, S. C.; Stirling, I.

2007-01-01

371

{sup 8}B proton halo via reaction and breakup cross section measurements  

SciTech Connect

The reaction cross section for {sup 8}B and {sup 7}Be and the breakup cross section for {sup 8}B on silicon have been measured for incident energies between 10 and 40 MeV/nucleon with a stack of silicon detectors. Secondary {sup 8}B and {sup 7}Be beams were obtained by use of the LISE spectrometer at GANIL. The stack of silicon detectors had the multiple purpose of slowing down the incident secondary beams, identifying the reaction products, and measuring their energy. The separate contributions of diffraction dissociation and absorption to the breakup have been determined. The parallel momentum distribution of {sup 7}Be resulting from the breakup of {sup 8}B has also been determined. The data are compared to theoretical calculations. {copyright} {ital 1996 The American Physical Society.}

Negoita, F.; Borcea, C.; Carstoiu, F. [IAP, P.O. Box MG-6, 76900 Bucharest-Magurele (Romania)] [IAP, P.O. Box MG-6, 76900 Bucharest-Magurele (Romania); Lewitowicz, M.; Saint-Laurent, M.G.; Anne, R.; Bazin, D.; Corre, J.M.; Roussel-Chomaz, P. [GANIL (IN2P3/CNRS,DSM/CEA) Boite Postale 5027, 14021 Caen Cedex (France)] [GANIL (IN2P3/CNRS,DSM/CEA) Boite Postale 5027, 14021 Caen Cedex (France); Borrel, V.; Guillemaud-Mueller, D.; Keller, H.; Mueller, A.C.; Pougheon, F.; Sorlin, O. [IPN, CNRS-IN2P3, 91406 Orsay Cedex (France)] [IPN, CNRS-IN2P3, 91406 Orsay Cedex (France); Lukyanov, S.; Penionzhkevich, Y.; Fomichev, A.; Skobelev, N.; Tarasov, O. [FLNR, Joint Institute for Nuclear Research, 141980 Dubna, Moscow Region (Russia)] [FLNR, Joint Institute for Nuclear Research, 141980 Dubna, Moscow Region (Russia); Dlouhy, Z. [NPI, 250 68 Rez (Czech Republic)] [NPI, 250 68 Rez (Czech Republic); Kordyasz, A. [Institute of Experimental Physics, Warsaw University, Hoza 69, 00681 Warsaw (Poland)] [Institute of Experimental Physics, Warsaw University, Hoza 69, 00681 Warsaw (Poland)

1996-10-01

372

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

373

Contribution of electric quadrupole and dipole-quadrupole interference terms in Coulomb breakup of 15C  

NASA Astrophysics Data System (ADS)

The effects of electric quadrupole ( E2) and dipole-quadrupole interference ( E1- E2) terms in the Coulomb breakup of 15C have been investigated within the framework of eikonal approximation. The sensitivity of Coulomb breakup cross section, differential in relative energy and Longitudinal Momentum Distribution (LMD) of core fragments, towards these terms have been examined. A very small (1% of E1) contribution of E2 transition has been predicted in integrated Coulomb breakup cross section. Further it is also found that the inclusion of E2 and E1- E2 terms introduces a small asymmetry in the peak of relative energy spectrum and also increases the peak height of the spectrum. The contribution of dipole-quadrupole interference terms is clearly shown in LMD, as it introduces an asymmetry in the shape of LMD and enhances the matching between the data and predictions.

Singh, P.; Kharb, S.; Singh, M.

2014-02-01

374

Practical method to identify orbital anomaly as spacecraft breakup in the geostationary region  

NASA Astrophysics Data System (ADS)

Identifying spacecraft breakup events is an essential issue for better understanding of the current orbital debris environment. This paper proposes an observation planning approach to identify an orbital anomaly, which appears as a significant discontinuity in archived orbital history, as a spacecraft breakup. The proposed approach is applicable to orbital anomalies in the geostationary region. The proposed approach selects a spacecraft that experienced an orbital anomaly, and then predicts trajectories of possible fragments of the spacecraft at an observation epoch. This paper theoretically demonstrates that observation planning for the possible fragments can be conducted. To do this, long-term behaviors of the possible fragments are evaluated. It is concluded that intersections of their trajectories will converge into several corresponding regions in the celestial sphere even if the breakup epoch is not specified and it has uncertainty of the order of several weeks.

Uetsuhara, Masahiko; Hanada, Toshiya

2013-09-01

375

Three-body breakup in dissociative electron attachment to the water molecule  

SciTech Connect

We report the results of {\\em ab initio} calculations on dissociative electron attachment (DEA) to water that demonstrate the importance of including three-body breakup in the dissociation dynamics. While three-body breakup is ubiquitous in the analogous process of dissociative recombination, its importance in low-energy dissociative electron attachment to a polyatomic target has not previously been quantified. Our calculations, along with our earlier studies of DEA into two-body channels, indicate that three-body breakup is a major component of the observed O- cross section. The local complex potential model provides a generally accurate picture of the experimentallyobserved features in this system, reproducing some quantitatively, others qualitatively, and one not at all.

Haxton, Daniel J.; Rescigno, Thomas N.; McCurdy, C. William

2008-08-28

376

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

NASA Technical Reports Server (NTRS)

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

Vargas, Mario

2012-01-01

377

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

378

Influence of insoluble surfactant on the deformation and breakup of a bubble or thread in a viscous fluid  

Microsoft Academic Search

The influence of surfactant on the breakup of a prestretched bubble in a quiescent viscous surrounding is studied by a combination of direct numerical simulation and the solution of a long-wave asymptotic model. The direct numerical simulations describe the evolution toward breakup of an inviscid bubble, while the effects of small but non-zero interior viscosity are readily included in the

M. Hameed; M. Siegel; Y.-N. Young; J. Li; M. R. Booty; D. T. Papageorgiou

2008-01-01

379

Breakup and Elastic Scattering in the {sup 9}Be + {sup 144}Sm system at near barrier energies  

SciTech Connect

Breakup and elastic scattering in the Be + {sup 144}Sm system, at near barrier energies, are investigated. We calculate theoretically the non-capture breakup cross section by performing coupled reaction channel calculations. The energy dependence of the optical potential does not show the usual threshold anomaly found in tightly bound systems.

Paes, B.; Garcia, V. N.; Lubian, J.; Gomes, P. R. S. [Instituto de Fisica, Universidade Federal Fluminense, Niteroi, R.J., 24210-340 (Brazil); Padron, I. [CEADEN, P.O. Box 6122, Havana (Cuba)

2010-05-21

380

Studies of Spray Breakup and Mixture Stratification in a Gasoline Direct Injection Engine Using KIVA3V  

Microsoft Academic Search

The Low Pressure spray Breakup (LPB) model of Papageorgakis and Assanis (1996) has been implemented in the multi-dimensional code KIVA-3V as an alternative to the standard Taylor Analogy Breakup (TAB) model. Comparison of spray predictions with measurements shows that the LPB model, in conjunction with the standard k- ? turbulence model, has the potential for simulating the evolution of hollow

Dennis N. Assanis; Sang Jin Hong; Akihiro Nishimura; George Papageorgakis; Bruno Vanzieleghem

2000-01-01

381

Did the Cocos-Nazca Spreading Center Form at a Transform Fault During Farallon Plate Break-Up?  

NASA Astrophysics Data System (ADS)

The break-up of the Farallon plate was the most important event during the Early Miocene plate tectonic reorganization of the East Pacific. The opening of a new oceanic spreading center perpendicular to the existing Pacific spreading is unique and probably had far-reaching consequences for the active continental margins of Central- and South America. Most of the original fissure where the Farallon plate split into the Cocos plate and the Nazca plate has already been subducted beneath Central- and South America together with much of the oceanic crust that was formed during the early phase of Cocos-Nazca spreading. This makes a full reconstruction of plate kinematics in the area back to the time of the opening poorly constrained and leaves many questions open about the mechanisms involved and the subduction zones affected by this event. The remains of the fissure in the Cocos- and Nazca plates have been identified offshore Costa Rica and Peru, resp., where they have been investigated with geophysical methods in recent years. The 600 km long still existing segment of the fissure in the Nazca plate has recently been almost completely mapped with swath bathymetry. If the origin of the Farallon break-up was a transform fault then this structure must also be present on the Pacific plate in the area conjugate to the Farallon remains offshore Costa Rica and Ecuador. However, very few ship data were available from this area in the Central Pacific so far and at the scale of satellite altimetry no such structures were detectable. During a R/V Sonne cruise the area in question was investigated with magnetics, gravity, and swath bathymetry to fill a major gap in the framework of East Pacific plate tectonic development and to test the transform fault hypothesis. The magnetic measurements were carried out with a gradiometer and a three-component vectormagnetometer to identify the almost north-south striking seafloor spreading anomalies at low geomagnetic latitude.

Barckhausen, U.; Ranero, C. R.; Weinrebe, W.

2004-12-01

382

Sparking limits, cavity loading, and beam breakup instability associated with high-current rf linacs  

SciTech Connect

The limitations on high-current rf linacs due to gap sparking, cavity loading, and the beam breakup instability are studied. It appears possible to achieve cavity accelerating gradients as high as 35 MV/m without sparking. Furthermore, a linear analysis, as well as self-consistent particle simulations of a multipulsed 10 kA beam, indicated that only a negligible small fraction of energy is radiated into nonfundamental cavity modes. Finally, the beam breakup instability is analyzed and found to be able to magnify initial radial perturbations by a factor of no more than about 20 during the beam transit time through a 1 GeV accelerator.

Faehl, R.J.; Lemons, D.S.; Thode, L.E.

1982-01-01

383

{sup 9}Be breakup polarization potential at near-barrier energies  

SciTech Connect

We use an approximate method to derive the polarization potential associated with breakup couplings in {sup 9}Be+{sup 144}Sm collisions at near-barrier energies. This method is particularly useful for collisions of weakly bound projectiles which break up into more than two fragments. We find that this potential is repulsive at large distances and produces long-range absorption. Using this potential, we evaluate breakup and fusion cross section. In the case of fusion, for which there is available data, our results are shown to be in very good agreement with the experiment.

Garcia, V. N.; Lubian, J.; Gomes, P. R. S. [Instituto de Fisica, Universidade Federal Fluminense, Av. Litoranea S-N, 24210-340 Niteroi, RJ (Brazil); Gomez-Camacho, A. [Departamento del Acelerador, Instituto Nacional de Investigaciones Nucleares, Apartado Postal 18-1027, C. P. 11801, Mexico, D. F. (Mexico); Canto, L. F. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, C. P. 68528, 21941-972 Rio de Janeiro (Brazil)

2009-09-15

384

Investigation of collision-induced breakup of raindrops by numerical simulations: First results  

NASA Astrophysics Data System (ADS)

Collision-induced breakup resulting from binary collisions of large drops has been investigated in the past by very few laboratory experiments. This process is here investigated using a 3D-CFD program based on direct numerical simulation. Besides same drop pairs as considered in the measurements also a number of additional ones are taken into account in order to complete the parameter space. First results with respect to coalescence efficiencies and fragment size distributions show some similarities to the findings of the past laboratory experiments but also certain differences. Excentricity of the collision event is responsible for the various breakup modes.

Beheng, K. D.; Jellinghaus, K.; Sander, W.; Roth, N.; Weigand, B.

2006-05-01

385

A CFD comparative study of bubble break-up models in a turbulent multiphase jet  

Microsoft Academic Search

In this paper several bubble break-up models are compared. They have been implemented in the CFX-4.4 fluid dynamic commercial\\u000a code, which uses the population balance equations for describing liquid\\/gas multi-phase flows. The models have been assessed\\u000a against published experimental data, obtained for air bubble break-up within a turbulent water jet. The model of Martnez-Bazn,\\u000a based on purely kinematics arguments, has

J. M. Martín-Valdepeñas; M. A. Jiménez; R. Barbero; F. Martín-Fuertes

2007-01-01

386

Effects of various lithospheric yield stresses and different mantle-heating modes on the breakup of the Pangea supercontinent  

NASA Astrophysics Data System (ADS)

simulations of three-dimensional spherical mantle convection were performed to investigate the effects of various lithospheric yield stresses and two different mantle-heating modes (i.e., mixed heating from the bottom and interior and purely internal heating) on the breakup of the Pangea supercontinent and the subsequent continental drift for the past 200 Myr. Results show that the continental breakup and subsequent continental drift are accomplished in mantle convection models with two different heating modes. This implies that active upwelling plumes from the core-mantle boundary are not necessarily required for the breakup of Pangea. In addition, I found that the continental breakup is only realized when choosing a moderate value of the yield stress (~120 MPa). The bound on the yield stress derived in the present study will potentially enable the self-consistent reconstruction of continental breakup and drift as well as the accompanying pattern on mantle convection since 200 Ma.

Yoshida, Masaki

2014-05-01

387

The proton conducting electrolyte BaTi0.5In0.5O2.75: determination of the deuteron site and its local environment  

NASA Astrophysics Data System (ADS)

Deuterated BaTi0.5In0.5O2.75 has been studied with neutron total (Bragg plus diffuse) scattering data, using both the Rietveld refinement method and the reverse Monte Carlo (RMC) modelling technique, to investigate the preferred proton site and its local structural environment. The Rietveld analysis shows an excellent fit between experimental data and a long-range cubic description of the BaTi0.5In0.5O2.53(OD)0.44 perovskite structure containing a statistical distribution of Ti and In ions at the centre of regular (Ti/In)O6 octahedra. However, an RMC analysis of the data reveals substantial local structural features that reflect limitations of the Rietveld method for studies of this type. The Ti-O and In-O pair distribution functions given by the RMC analysis are markedly different from each other, with average Ti-O and In-O bond distances of 2.035 Å and 2.159 Å, respectively. The InO6 octahedra are regular in shape whereas the TiO6 octahedra are distorted. The average O-D bond distance is roughly 0.96 Å, and the preferred deuteron sites have a second nearest oxygen distance of 2.13 Å, which confirms localized tilting of the deuteron and indicates a substantial degree of hydrogen bonding. The impact of octahedral distortion and hydrogen bonding on the proton conduction mechanism is discussed.

Norberg, Stefan T.; Rahman, Seikh M. H.; Hull, Stephen; Knee, Christopher S.; Eriksson, Sten G.

2013-11-01

388

Surface breakup and air bubble formation by drop impact in the irregular entrainment region  

NASA Astrophysics Data System (ADS)

Drop impact on a water surface can be followed by underwater sounds originating not at the drop impact but when the entrained bubbles oscillate. Although the sound mechanism in the regular bubble entrainment region is well-known, there is less knowledge on the impact phenomena in the irregular bubble entrainment region where various situations can exist, such as many types of bubble formation or even no bubble generation under some conditions. In the present study, the aim is to clarify the dynamics of the water surface after the impact of a primary drop, mainly with diameter 5.2, 5.7 and 6.2mm, each of which is accompanied by a single satellite drop. Special attention was paid to the breakup behaviour of the water surface for Froude number Fr < 300. It was found that three underwater sounds were generated for a single drop impact, besides the sound due to impact itself. The first two were audible to the human ear, but the third one was almost inaudible. The first underwater sound resulted from the oscillation of a single air bubble formed as a result of the satellite drop impact on the bottom of the contracting cavity, and the second sound was due to the oscillation of air bubbles generated during the collapse of the water column. The formation of these air bubbles strongly depends on the Froude number, Weber number (or Bond number) and the aspect ratio of the drop at impact, although involving probability characteristics. Furthermore it is suggested that an air bubble entrapped in a water column plays an important role in increasing the probability of contact between the column surface and the curved free surface. A Japanese Suikinkutsu was introduced as an application of drop-impact-induced sounds. Using an open-type Suikinkutsu an additional experiment was carried out with larger drops with average diameters of 6.2, 7.2 and 7.8, mm.

Tomita, Y.; Saito, T.; Ganbara, S.

389

Case for Upper Miocene continental break-up in western Afar, southern Red Sea rift  

NASA Astrophysics Data System (ADS)

We describe the distribution, nature and timing of extension in the youthful Western Afar in order to infer mechanisms for continental break-up. New and existing remote sensing, fieldwork and structural analyses calibrated by geochronology were integrated to define rift stages and the distribution and nature of volcanic units and structures that accommodate extension. Oligo-Miocene continental rift basins of the Southern Red Sea rift, Ethiopia are typical steep-sided continental rift graben, but contain almost exclusively volcanic fill. Rift segmentation was defined by border faults that were the locus of strain, but strain migrated to magmatic centres within the basins in the Upper Miocene. Widespread basaltic volcanism in the Upper Miocene led to extension, burial, riftward rotation and seismic reactivation of Oligo-Miocene rift basins. These basalts were sourced from linear magmatic segments that are independent of the older border fault segmentation. Cycles of subsidence and volcanism gave the basalt successions a concave-down profile similar to seaward-dipping reflectors (SDRs) on buried volcanic margins. Mid-Miocene propagation of the Main Ethiopian rift (MER) arm into the Afar Depression led to overprinting of the early Red Sea rift structures. We suggest that the locus of strain in western Afar jumped from Upper Miocene Southern Red Sea magmatic segments to Plio-Quaternary MER magmatic segments. The distribution of strain across the western Afar margin, and age of SDR-like basalts and the intersecting Southern Red Sea and Main Ethiopian rifts suggests that the Southern Red Sea magmatic segments were abandoned in the Upper Miocene leaving SDRs stranded above Oligo-Miocene rift basins, possibly due to the northward propagation of the seismically and volcanically active MER.

Wolfenden, E.; Ebinger, C.; Yirgu, G.; Kelley, S.; Deino, A.; Renne, P.

2003-04-01

390

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

391

A low-background detector for the study of electron-antineutrino interactions on deuterons and protons  

SciTech Connect

The subject of this dissertation is a detector system capable of a high-precision measurement of the cross section for the disintegration of the deuteron via neutral and charged current interactions with reactor antineutrinos ([bar [nu

Riley, S.P.

1992-01-01

392

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

393

Deuteron and antideuteron production in Au+Au collisions at square root of s(NN)=200 GeV.  

PubMed

The production of deuterons and antideuterons in the transverse momentum range 1.1deuteron and antideuteron spectra with that of proton and antiproton, has been performed. The coalescence probability is equal for both deuterons and antideuterons and it increases as a function of p(T), which is consistent with an expanding collision zone. Comparing (anti)proton yields, p /p=0.73+/-0.01, with (anti)deuteron yields, d /d=0.47+/-0.03, we estimate that n /n=0.64+/-0.04. The nucleon phase space density is estimated from the coalescence measurement. PMID:15903909

Adler, S S; Afanasiev, S; Aidala, C; Ajitanand, N N; Akiba, Y; Alexander, J; Amirikas, R; Aphecetche, L; Aronson, S H; Averbeck, R; Awes, T C; Azmoun, R; Babintsev, V; Baldisseri, A; Barish, K N; Barnes, P D; Bassalleck, B; Bathe, S; Batsouli, S; Baublis, V; Bazilevsky, A; Belikov, S; Berdnikov, Y; Bhagavatula, S; Boissevain, J G; Borel, H; Borenstein, S; Brooks, M L; Brown, D S; Bruner, N; Bucher, D; Buesching, H; Bumazhnov, V; Bunce, G; Burward-Hoy, J M; Butsyk, S; Camard, X; Chai, J-S; Chand, P; Chang, W C; Chernichenko, S; Chi, C Y; Chiba, J; Chiu, M; Choi, I J; Choi, J; Choudhury, R K; Chujo, T; Cianciolo, V; Cobigo, Y; Cole, B A; Constantin, P; d'Enterria, D; David, G; Delagrange, H; Denisov, A; Deshpande, A; Desmond, E J; Devismes, A; Dietzsch, O; Drapier, O; Drees, A; du Rietz, R; Durum, A; Dutta, D; Efremenko, Y V; El Chenawi, K; Enokizono, A; En'yo, H; Esumi, S; Ewell, L; Fields, D E; Fleuret, F; Fokin, S L; Fox, B D; Fraenkel, Z; Frantz, J E; Franz, A; Frawley, A D; Fung, S-Y; Garpman, S; Ghosh, T K; Glenn, A; Gogiberidze, G; Gonin, M; Gosset, J; Goto, Y; Granier de Cassagnac, R; Grau, N; Greene, S V; Grosse Perdekamp, M; Guryn, W; Gustafsson, H-A; Hachiya, T; Haggerty, J S; Hamagaki, H; Hansen, A G; Hartouni, E P; Harvey, M; Hayano, R; Hayashi, N; He, X; Heffner, M; Hemmick, T K; Heuser, J M; Hibino, M; Hill, J C; Holzmann, W; Homma, K; Hong, B; Hoover, A; Ichihara, T; Ikonnikov, V V; Imai, K; Isenhower, D; Ishihara, M; Issah, M; Isupov, A; Jacak, B V; Jang, W Y; Jeong, Y; Jia, J; Jinnouchi, O; Johnson, B M; Johnson, S C; Joo, K S; Jouan, D; Kametani, S; Kamihara, N; Kang, J H; Kapoor, S S; Katou, K; Kelly, S; Khachaturov, B; Khanzadeev, A; Kikuchi, J; Kim, D H; Kim, D J; Kim, D W; Kim, E; Kim, G-B; Kim, H J; Kistenev, E; Kiyomichi, A; Kiyoyama, K; Klein-Boesing, C; Kobayashi, H; Kochenda, L; Kochetkov, V; Koehler, D; Kohama, T; Kopytine, M; Kotchetkov, D; Kozlov, A; Kroon, P J; Kuberg, C H; Kurita, K; Kuroki, Y; Kweon, M J; Kwon, Y; Kyle, G S; Lacey, R; Ladygin, V; Lajoie, J G; Lebedev, A; Leckey, S; Lee, D M; Lee, S; Leitch, M J; Li, X H; Lim, H; Litvinenko, A; Liu, M X; Liu, Y; Maguire, C F; Makdisi, Y I; Malakhov, A; Manko, V I; Mao, Y; Martinez, G; Marx, M D; Masui, H; Matathias, F; Matsumoto, T; McGaughey, P L; Melnikov, E; Messer, F; Miake, Y; Milan, J; Miller, T E; Milov, A; Mioduszewski, S; Mischke, R E; Mishra, G C; Mitchell, J T; Mohanty, A K; Morrison, D P; Moss, J M; Mühlbacher, F; Mukhopadhyay, D; Muniruzzaman, M; Murata, J; Nagamiya, S; Nagle, J L; Nakamura, T; Nandi, B K; Nara, M; Newby, J; Nilsson, P; Nyanin, A S; Nystrand, J; O'brien, E; Ogilvie, C A; Ohnishi, H; Ojha, I D; Okada, K; Ono, M; Onuchin, V; Oskarsson, A; Otterlund, I; Oyama, K; Ozawa, K; Pal, D; Palounek, A P T; Pantuev, V; Papavassiliou, V; Park, J; Parmar, A; Pate, S F; Peitzmann, T; Peng, J-C; Peresedov, V; Pinkenburg, C; Pisani, R P; Plasil, F; Purschke, M L; Purwar, A K; Rak, J; Ravinovich, I; Read, K F; Reuter, M; Reygers, K; Riabov, V; Riabov, Y; Roche, G; Romana, A; Rosati, M; Rosnet, P; Ryu, S S; Sadler, M E; Saito, N; Sakaguchi, T; Sakai, M; Sakai, S; Samsonov, V; Sanfratello, L; Santo, R; Sato, H D; Sato, S; Sawada, S; Schutz, Y; Semenov, V; Seto, R; Shaw, M R; Shea, T K; Shibata, T-A; Shigaki, K; Shiina, T; Silva, C L; Silvermyr, D; Sim, K S; Singh, C P; Singh, V; Sivertz, M; Soldatov, A; Soltz, R A; Sondheim, W E; Sorensen, S P; Sourikova, I V; Staley, F; Stankus, P W; Stenlund, E; Stepanov, M; Ster, A; Stoll, S P; Sugitate, T; Sullivan, J P; Takagui, E M; Taketani, A; Tamai, M; Tanaka, K H; Tanaka, Y; Tanida, K; Tannenbaum, M J; Tarján, P; Tepe, J D; Thomas, T L; Tojo, J; Torii, H; Towell, R S; Tserruya, I; Tsuruoka, H; Tuli, S K; Tydesjö, H; Tyurin, N; van Hecke, H W; Velkovska, J; Velkovsky, M; Veszprémi, V; Villatte, L; Vinogradov, A A; Volkov, M A; Vznuzdaev, E; Wang, X R; Watanabe, Y; White, S N; Wohn, F K; Woody, C L; Xie, W; Yang, Y; Yanovich, A; Yokkaichi, S; Young, G R; Yushmanov, I E; Zajc, W A; Zhang, C; Zhou, S; Zhou, S J; Zolin, L

2005-04-01

394

RADIOACTIVITIES PRODUCED IN COMMONLY USED MATERIALS BY PROTON AND DEUTERON BEAMS UP TO 10 MeV  

Microsoft Academic Search

Proton- and deuteron-induced nuclear reactions which produce radioactivities are surveyed. Reactions with up to 10-MeV protons or deuterons on carbon, aluminum (#6061), titanium-alloy, stainless steel (#304), and brass targets are identified. For each target material, the nuclear reaction, associated radioactivity, half-life, and decay products are tabulated. Measured cross sections from the published literature are used to determine reaction yields for

F. C. Young; D. V. Rose

1996-01-01

395

Neutron yields from thick 12C and 9Be targets irradiated by 50 and 65 MeV deuterons  

Microsoft Academic Search

Absolute intensities, angular distributions and energy spectra of neutrons emitted from thick 12C and 9Be targets irradiated with 50 and 65 MeV deuterons, respectively, have been measured. The neutron spectra were measured by time-of-flight (TOF) technique. The detectors provided continuous coverage from 0° to 60° where a significant angular dependence of emitted neutrons was found. The yield of 0.109(10) neutrons\\/deuteron

Z. Radivojevic; A. Honkanen; J. Äystö; V. Lyapin; V. Rubchenya; W. H. Trzaska; D. Vakhtin; G. Walter

2001-01-01

396

Preservation and control of the proton and deuteron polarizations in the proposed electron-ion collider at Jefferson Lab  

SciTech Connect

We propose a scheme of preserving the proton and deuteron beam polarizations during acceleration and storage in the proposed electron-ion collider at Jefferson Lab. This scheme allows one to provide both the longitudinal and transverse polarization orientations of the proton and deuteron beams at the interaction points of the figure-8 ion collider ring. We discuss questions of matching the polarization direction at all stages of the beam transport including the pre-booster, large booster and ion collider ring.

Kondratenko, Anatoliy [Scientific and Technical Laboratory Zaryad, Novosibirsk (Russian Federation); Derbenev, Yaroslav S. [JLAB, Newport News, VA (United States); Filatov, Yury [Moscow Institute of Physics and Technology, Dolgoprudny (Russian Federation); Lin, Fanglei [JLAB, Newport News, VA (United States); Morozov, Vasiliy [JLAB, Newport News, VA (United States); Kondratenko, M. A. [Scientific and Technical Laboratory Zaryad, Novosibirsk (Russian Federation); Zhang, Yuhong [JLAB, Newport News, VA (United States)

2014-01-01

397

Evidence for the production of d-d fusion neutrons during electrolytic infusion of deuterons into a palladium cylinder  

SciTech Connect

A lengthy experiment for the observation of deuteron-deuteron (d-d) fusion neutrons emanating from a massive palladium cylinder is described. The experimental results are discussed in the framework of a plasmalike model for fusion in condensed matter, resulting in fusion rates of {lambda}{sup pl}{sub d{minus}d} = (1.19 {plus minus} 0.15) {times} 10{sup {minus}44} s{sup {minus}1}.

Ohms, D.; Paffrath, E.; Rahner, D.; Schwierz, R.; Selliger, D.; Stiekl, P.; Wiesener, K.; Wustner, P.; Bittner, M.; Ludwig, G.; Meister, A.; Muller, J. (Dresden Univ. of Technology, Physics and Chemistry Dept., Mommsenstrasse 13, O-8027 Dresden (DE))

1991-07-01

398

Field and experimental constraints on the deformation and break-up up of injected magma (Invited)  

NASA Astrophysics Data System (ADS)

Understanding the mechanics that control mafic schlieren and enclave formation is a central issue in volcanology for interpreting the conditions of the unerupted material in a chamber. Field observations from the Tuolumne Intrusive Suite (TIS), USA, demonstrate that meter-scale migrating tubes, or “ladder dikes,” can be strongly deformed by shearing motions in the magma chamber. These delicate features offer preserved length scales of deformation that can be used to infer fundamental quantities controlling the rheology of silicic magma. Here we investigate what governs the dynamics of these tube-like structures in a shear flow using analog experiments, which are motivated by field observations from the TIS. Using variations in yield strength of the injected material, buoyancy, and ambient flow behavior, we aim to characterize the deformation of the tubes under a wide range of conditions. The experiments are conducted in an 8 cm high and 60 cm wide cylindrical tank. In all experiments the tank is filled to a depth of 7 cm with corn syrup (? = 1430 kg/m3, µ = 280 Pa s). A rigid rotating plate is driven from above by an external motor creating a simple shear flow in the corn syrup with rotation speeds varying between 0.08 - 12 rpm. The experiment involves a downward injection of a controlled volume of a particle-fluid mixture. The fluid is the same corn syrup used for the ambient fluid and the particles are glass powder (? = 2600 kg/m3, d = 1µm) and zirconium silicate spheres (? = 3600 kg/m3, d=0.4mm). Our results show that the particle-fluid tube may follow two end-member regimes depending on the shear stress/buoyancy force ratio (V*) and the viscous stress/yield stress ratio (R) imposed initially. At low R values (< 1) and low V* values (<100) as well as all R values for V* > 100, the injected tube becomes gravitationally unstable and breaks up into blobs separated by thin strands of interstitial tube material. At high R values (> 1) and low V* values (<100), the injected tube is too stiff and does not go unstable or breakup. Initial field observations of migrating tubes (Paterson 2009) in the TIS suggest that the break-up of these features can be linked to the yield strength of the magma during deformation. Here, we present a field investigation that includes detailed mapping of ~100 migrating tubes in the Cathedral Peak Granite (along with some tubes in the Half Dome granite). Preliminary results suggest that a few long tubes appear to have been broken up into regularly spaced sections. Interestingly, the majority of the mapped tubes (specifically where they occur in large clusters) are located near a contact with either host rock or another intrusive unit in the TIS and are oriented roughly perpendicular to that contact. The preserved length scales of deformation are compared to experimental regimes in which tubes break up into blobs.

Hodge, K. F.; Carazzo, G.; Jellinek, M.

2010-12-01

399

Estimating the Break-Up Diameter of an Impulsively Driven Initially Smooth Fluid Cylinder  

NASA Astrophysics Data System (ADS)

This analysis pursues the underlying physics governing breakup of a fluid, which is initially contained in a smooth thin walled steel vessel, after being impacted by a high velocity aluminum sphere. It has been observed experimentally that the impact generates a radially expanding cohesive thin shell of liquid which stays intact to at least a diameter 8 times that of the original cylinder diameter. The cohesive nature of the shell is aided by the fact that the shell is expanding in a vacuum. If it is assumed that the shell will break once the height scale of the fastest growing instability exceeds the shell thickness then a linear Richtmyer-Meshkov stability analysis under predicts the break-up diameter. The difficulty with such an approach is determining the proper initial disturbance length scale for an initially smooth geometry. In this analysis it is assumed that the fracture process of the thin walled steel vessel imposes an initial disturbance on the expanding liquid. By combining this with the geometry of the cylinder an initial disturbance length scale can be determined. A breakup model is constructed by combining an initial disturbance derived from the characteristic fragment size of the vessel with a nonlinear Richtmyer-Meshkov growth rate model for the instability growth rate. This model extends the breakup diameter of the expanding liquid shell beyond 8 diameters.

Borg, John P.

2004-07-01

400

Employment Security in the Aftermath of the Break-up of Rover Group  

Microsoft Academic Search

The scale and the speed with which Rover Group was broken up by BMW in March 2000 was unprecedented in the context of British industrial relations. This working paper covers the last eighteen months of BMW's ownership of Rover Group and details: the key phases leading to the break-up of the company; the subsequent collapse of the bid by Alchemy

Joy Batchelor

401

Tidal Breakup of the Nucleus of Comet Shoemaker-Levy 9  

NASA Technical Reports Server (NTRS)

The breakup of Comet Shoemaker-Levy 9 is discussed both in the context of splitting as a cometary phenomenon and comparing it with other split comets. The physical appearance of the comet is described, diagnostic features are identified, and implications are noted for modelling the event.

Sekanina, Z.

1995-01-01

402

Fracture zones in the equatorial Atlantic and the breakup of western Pangea  

Microsoft Academic Search

The early breakup of western Pangea has been investigated by mapping the pattern of fracture zones and distribution of seismic reflectors within the sedimentary cover of the Atlantic between the Cape Verde Islands and the equator. Two distinct sets of transverse oceanic lineaments are present, separated by the Guinea Fracture Zone near lat 10°N. Lineaments to the north are associated

E. J. W. Jones

1987-01-01

403

Reduction of Beam Breakup Growth by Cavity Cross-Couplings in Recirculating Accelerators.  

National Technical Information Service (NTIS)

It is shown that cross-coupling among cavities may reduce beam breakup (BBU) growth in a recirculating accelerator. The main reason for this growth reduction appears to be the sharing of the deflecting mode energy among coupled cavities. The result is bas...

D. Chernin D. Colombant Y. Y. Lau

1990-01-01

404

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

NASA Technical Reports Server (NTRS)

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

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

2013-01-01

405

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

ERIC Educational Resources Information Center

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

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

2013-01-01

406

Breakup Flooding and Nutrient Source of Colville River Delta during 1973.  

National Technical Information Service (NTIS)

During breakup, floodwater from the Colville River moves seaward as a wedge beneath the sea ice. The interface separating the advancing fresh water from the sea water beneath is narrow such that sharp contrasts occur in temperature and salinity within sho...

R. A. Hamilton C. L. Ho H. J. Walker

1974-01-01

407

An evaluation of perceived color break-up on field-sequential color displays  

Microsoft Academic Search

Field-Sequential Color (FSC) displays have been discussed for a long time. Its main concept is to remove a color filter so that we may increase the light transmittance of an LCD panel. However, FSC displays have a major problem: color break-up (CBU). Moreover, it is difficult to quantify the CBU in saccadic eye movements, because the phenomenon occurs as quickly

Masamitsu Kobayashi; Akiko Yoshida; Yasuhiro Yoshida

2011-01-01

408

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

409

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

410

Incoherent {phi} photo-production from deuteron in SPring-8/LEPS  

SciTech Connect

We present measurements of differential cross sections and decay asymmetries of incoherent {phi}-meson photo-production from the deuteron at forward angles using linearly polarized photons beam in energy range from the production threshold to E = 2.4 GeV. The experiment was performed at the SPring-8/LEPS facility. The differential cross section of incoherent production shows a large suppression compared with the free proton case. The reduction for the deuteron cannot be clearly explained in terms of simple isospin asymmetry. The decay asymmetry of incoherent {phi} photo-production shows that the eta exchange process is small. Since the exclusive K{sup +}K{sup -}p cross section shows the same reduction with incoherent, both the proton and neutron cross section reduce similarly. Consequently, the {pi}-{eta} interference effect is small too. The present results suggest that our understanding of {phi} photo-production within a nucleus should be rearranged.

Miyabe, M. [Research Center of Nuclear Physics Osaka Univ (Japan)

2011-10-21

411

Probing the High Momentum Component of the Deuteron at High Q2  

NASA Astrophysics Data System (ADS)

The H2(e,e'p)n cross section at a momentum transfer of 3.5(GeV/c)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 ?nq and to extract missing momentum distributions for fixed values of ?nq up to 0.55GeV/c. In the region of 35°??nq?45° 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.; Aniol, K.; Arrington, J.; Batigne, G.; Bosted, P.; Camsonne, A.; Chang, G.; Chen, J. P.; Choi, S.; Deur, A.; Epstein, M.; Finn, J. M.; Frullani, S.; Furget, C.; Garibaldi, F.; Gayou, O.; Gilman, R.; Hansen, O.; Hayes, D.; Higinbotham, D. W.; Hinton, W.; Hyde, C.; Ibrahim, H.; de Jager, C. W.; Jiang, X.; Jones, M. K.; Kaufman, L. J.; Klein, A.; Kox, S.; Kramer, L.; Kumbartzki, G.; Laget, J. M.; Lerose, J.; Lindgren, R.; Margaziotis, D. J.; Markowitz, P.; McCormick, K.; Meziani, Z.; Michaels, R.; Milbrath, B.; Mitchell, J.; Monaghan, P.; Moteabbed, M.; Moussiegt, P.; Nasseripour, R.; Paschke, K.; Perdrisat, C.; Piasetzky, E.; Punjabi, V.; Qattan, I. A.; Quéméner, G.; Ransome, R. D.; Raue, B.; Réal, J. S.; Reinhold, J.; Reitz, B.; Roché, R.; Roedelbronn, M.; Saha, A.; Slifer, K.; Solvignon, P.; Sulkosky, V.; Ulmer, P. E.; Voutier, E.; Weinstein, L. B.; Wojtsekhowski, B.; Zeier, M.

2011-12-01

412

Pionic and hidden-color, six-quark contributions to the deuteron b1 structure function  

NASA Astrophysics Data System (ADS)

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 values of x of about 0.1. A simple model for a hidden-color, six-quark configuration (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 and Kumano sum rule is investigated and found to be a useful guide to understanding various possible effects that may contribute.

Miller, Gerald A.

2014-04-01

413

Measurements of deuteron-induced activation cross-sections for IFMIF accelerator structural materials  

NASA Astrophysics Data System (ADS)

Activation cross-sections for deuteron-induced reactions in aluminum, iron, copper, tantalum and tungsten were measured by using the stacked-foil method. The stacked foils were irradiated with a deuteron beam at TIARA facility in JAERI. We obtained the activation cross-sections for 27Al(d,x) 22,24Na, natFe(d,x) 55,56Co, natCu(d,x) 61Cu, natCu(d,x) 62Zn, natTa(d,x) 178,180Ta and natW(d,x) 181,183Re in 20-40 MeV region. These cross-sections were compared with other experimental ones and the data in the ACSELAM library calculated by the ALICE-F code.

Nakao, M.; Hori, J.; Ochiai, K.; Kubota, N.; Sato, S.; Yamauchi, M.; Ishioka, N. S.; Nishitani, T.

2006-06-01

414

Probing the high momentum component of the deuteron at high Q2.  

PubMed

The (2)H(e,e'p)n cross section at a momentum transfer of 3.5 (GeV/c)(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 ?(nq) and to extract missing momentum distributions for fixed values of ?(nq) up to 0.55??GeV/c. In the region of 35°??(nq)?45° 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. PMID:22243152

Boeglin, W U; Coman, L; Ambrozewicz, P; Aniol, K; Arrington, J; Batigne, G; Bosted, P; Camsonne, A; Chang, G; Chen, J P; Choi, S; Deur, A; Epstein, M; Finn, J M; Frullani, S; Furget, C; Garibaldi, F; Gayou, O; Gilman, R; Hansen, O; Hayes, D; Higinbotham, D W; Hinton, W; Hyde, C; Ibrahim, H; de Jager, C W; Jiang, X; Jones, M K; Kaufman, L J; Klein, A; Kox, S; Kramer, L; Kumbartzki, G; Laget, J M; LeRose, J; Lindgren, R; Margaziotis, D J; Markowitz, P; McCormick, K; Meziani, Z; Michaels, R; Milbrath, B; Mitchell, J; Monaghan, P; Moteabbed, M; Moussiegt, P; Nasseripour, R; Paschke, K; Perdrisat, C; Piasetzky, E; Punjabi, V; Qattan, I A; Quéméner, G; Ransome, R D; Raue, B; Réal, J S; Reinhold, J; Reitz, B; Roché, R; Roedelbronn, M; Saha, A; Slifer, K; Solvignon, P; Sulkosky, V; Ulmer, P E; Voutier, E; Weinstein, L B; Wojtsekhowski, B; Zeier, M

2011-12-23

415

Deuteron whistler and trans-equatorial propagation of the ion cyclotron whistler  

NASA Technical Reports Server (NTRS)

The paper investigates two unusual types of ion cyclotron whistlers that were found in the low-latitude topside ionosphere by analyzing ISIS VLF electric-field data received at Kashima, Japan. One type is characterized by an asymptotic frequency equal to one half the local proton gyrofrequency; the asymptotic frequency of the other type corresponds to the minimum proton gyrofrequency along the geomagnetic field line passing through the satellite. The observations are compared with theoretical spectrograms of the ion cyclotron whistlers computed for appropriate model distributions of electrons and ions in the topside ionosphere. It is found that the whistlers with the asymptotic frequency of one half the local proton gyrofrequency are deuteron whistlers and that the other whistlers are due to the transequatorial propagation of proton or deuteron whistlers originating in the southern hemisphere.

Watanabe, S.; Ondoh, T.

1976-01-01

416

Quasielastic electron-deuteron scattering in the weak-binding approximation  

NASA Astrophysics Data System (ADS)

We perform a global analysis of all available electron-deuteron (ed) quasielastic scattering data using Q2-dependent smearing functions that describe inclusive inelastic ed scattering within the weak-binding approximation. We study the dependence of the cross sections on the deuteron wave function and the off-shell extrapolation of the elastic electron-nucleon cross sections, which show particular sensitivity at x ?1. The excellent overall agreement with data over a large range of Q2 and x suggests a limited need for effects beyond the impulse approximation, with the exception of the very high-x and very low-Q2 regions, where short-range meson exchange and final state interaction effects become more relevant.

Ethier, J. J.; Doshi, N.; Malace, S.; Melnitchouk, W.

2014-06-01

417

Using Synthetic Aperture Radar to Study River Ice Breakup on the Kuparuk River, Northern Alaska  

NASA Astrophysics Data System (ADS)

A combined use of remote sensing techniques and in-situ measurements is an effective approach to study Arctic hydrology, given the vastness, complexity, and logistical challenges posed by most Arctic watersheds. Remote sensing techniques can provide tools to assess the geospatial variations that form the integrated response of a river system and, therefore, provide important details to study one of the effects of climate change on the remote Arctic environment. This study investigates the breakup response of the Kuparuk River on the North Slope of Alaska using synthetic aperture radar (SAR). Imagery and runoff data collected during the spring and summer months between 2001 and 2010 from the Lower Kuparuk River are included in the analysis, which totals 65 SAR images. Image processing results have been calibrated with in-situ stream gauge data provided by USGS gauging station 15896000, on the Lower Kuparuk River, near the town of Deadhorse, Alaska. A time series was assembled to examine the breakup initiation in the subsets through statistical analysis. Images were stacked, geocoded using a Fast Fourier Transform, subset, masked, and divided into subsections. The statistics of each subsection were then compiled and analyzed. Arctic river breakup is a dynamic process. Therefore, we expected drastic change in river surface conditions to correspond to a large variance in backscatter between river subsections. However, before and after breakup we expected image subsections to have largely homogenous statistics. This was verified in nearly all of the image sets, although some variance still existed before and after the breakup event as a result of other conflicting variables. Changes in wind velocity, water depth, and size of point bars all contributed to these confounding variances. Combined with a comprehensive field campaign, SAR imagery interpretations have the potential to develop into a useful monitoring tool for monitoring Arctic rivers and developing resource management plans for neighboring communities.

Floyd, A.; Prakash, A.; Meyer, F. J.; Gens, R.; Liljedahl, A. K.

2012-12-01

418

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

419

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.

Marshall, Tara C.; Bejanyan, Kathrine; Ferenczi, Nelli

2013-01-01

420

Measurements of deuteron threshold electrodisintegration: A probe of short-range meson exchange  

SciTech Connect

The threshold electrodisintegration of the deuteron was measured with good energy resolution to a maximum four-momentum transfer squared of 42 fm{sup {minus}2}. The data are compared with meson exchange calculations that show sensitivity to the choice of exchange-current form factor, the nucleon electromagnetic form factors, and the nucleon-nucleon potential. While conventional theories can give a reasonable description of the data, comparison of the data with quark cluster calculations shows poor agreement.

Lee, K.S.; Schmitt, W.; Baghaei, H.; Beck, D.; Bosted, P.E.; Churchwell, S.; Frois, B.; Hicks, R.S.; Hotta, A.; Martino, J.; Miskimen, R.A.; Peterson, G.A.; Platchkov, S.; Spengos, M.; Turchinetz, W.; Wang, K.; Williamson, C.F.; Yates, T.; Zumbro, J.D. (University of Massachusetts, Amherst, Massachusetts (USA) Massachusetts Institute of Technology, Cambridge, Massachusetts (USA) The American University, Washington, D.C. (USA) Centre d'Etudes Nucleaires de Saclay, F-91191 Gif-sur-Yvette (France) University of Illinois, Champaign, Illinois (USA) Shizuoka University, Shizuoka 422 (Japan))

1991-11-04

421

Two-body photodisintegration of the deuteron in the region of small momentum transfers  

Microsoft Academic Search

We propose to measure the differential cross section for the deuteron photodisintegration at t=0+\\/-0.125 (GeV\\/cc)2 and over the energy range from 0.9 to 1.5 GeV, in order to check the prediction of the Regge phenomenology. The experiment can use the CEBAF Large Acceptance Spectrometer (CLAS) and run concurrently with PR-89-045, ``Studies of kaon photoproduction on deuterium.'' The time request for

E. de Sanctis

1992-01-01