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1

Deuteron breakup mechanism in the intermediate-energy region  

SciTech Connect

In an earlier investigation, we have explored the possibility of explaining the deuteron breakup mechanism in terms of the Udagawa and Tannura (UT) formalism of the breakup-fusion process. The experimental doubly differential data were very well reproduced for the test case studies. However, the application of UT formalism of the spirit of DWBA involves the use of optical-model parameters for different nuclei and at different energies. The optical model parameters are not always unique. In the present study we investigate the deuteron breakup mechanism in terms of the semiclassical models of Serber (for the nuclear interaction part) and Dancoff (for the electromagnetic dissociation). In the case of Serber model the modification due to the finite range of the deuteron and the Glauber correction for the diffractive disassociation are considered. The modified deuteron breakup cross section either for the (d,p) or the (d,n) process is proportional to the product of the target radius and the deuteron radius (R{sub target} {center dot} R{sub deuteron}). The predicted proton/neutron spectrum is centered around 1/2 E{sub d} and forward peaked. The Coulomb dissociation of deuteron is attributed to the deuteron dipole excitation in the presence of the nuclear Coulomb field. The neutron/proton spectrum, resulting from the Coulomb breakup of the deuteron, is highly forward peaked and also centered around 1/2 E{sub d}. The systematics of the deuteron breakup neutron/proton spectra are investigated for medium to heavy target nuclei at 50--200 MeV deuteron energies. 10 refs., 4 figs.

Divadeenam, M.; Ward, T.E.

1991-01-01

2

Deuteron-deuteron scattering above four-nucleon breakup threshold  

E-print Network

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

A. Deltuva; A. C. Fonseca

2015-02-06

3

Deuteron-deuteron scattering above four-nucleon breakup threshold  

E-print Network

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

Deltuva, A

2015-01-01

4

Deuteron-deuteron scattering above four-nucleon breakup threshold  

NASA Astrophysics Data System (ADS)

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

Deltuva, A.; Fonseca, A. C.

2015-03-01

5

Neutron-deuteron breakup and quasielastic scattering  

E-print Network

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

Ohlson, Alice Elisabeth

2009-01-01

6

Investigation of the intermediate-energy deuteron breakup reaction  

SciTech Connect

The Udagawa-Tamura formalism is employed to calculate the proton singles both in the bound and unbound regions. Both the Elastic-Breakup (EB) and the Breakup-Fusion (BF) processes are considered to calculate the doubly-differential cross section for light and intermediate mass nuclei. The calculated spectra for 25 and 56 MeV deuterons reproduce the experimental spectra very well except for the spectra at large angle and at low energies, of the outgoing particle. Contributions due to precompound and evaporation processes are estimated to supplement the spectral results based on the Elastic-Breakup and Breakup-Fusion mechanisms. An extension of the model calculations to higher deuteron energies is being made to test the (EB + BF) model limitations. 5 refs., 1 fig.

Divadeenam, M.; Ward, T.E.; Mustafa, M.G.; Udagawa, T.; Tamura, T.

1989-01-01

7

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

8

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

E-print Network

We successfully identified a few final states in deuteron-deuteron scattering at 65 MeV/nucleon at KVI using a unique and advanced detection system called BINA. This facility enabled us to perform cross sections and polarization measurements with an excellent statistical and systematical precision. The analysis procedure and part of the results of the three-body break-up channel in deuteron-deuteron scattering at 65 MeV/nucleon are presented in this paper.

A. Ramazani-Moghaddam-Arani; H. R. Amir-Ahmadi; A. D. Bacher; C. D. Bailey; A. Biegun; M. Eslami-Kalantari; I. Gašpari?; L. Joulaeizadeh; N. Kalantar-Nayestanaki; St. Kistryn; A. Kozela; H. Mardanpour; J. G. Messchendorp; A. M. Micherdzinska; H. Moeini; S. V. Shende; E. Stephan; E. J. Stephenson; R. Sworst

2010-01-09

9

Neutrino Emissivities from Deuteron Breakup and Formation in Supernovae  

NASA Astrophysics Data System (ADS)

Neutrino emissions from electron/positron capture on the deuteron and the nucleon-nucleon fusion processes in a supernova core are studied. These weak processes are evaluated in an approach which consists of one-nucleon and two-nucleon meson-exchange currents and nuclear wave functions generated by a high precision nucleon-nucleon potential. In addition to the cross sections for these processes involving the deuteron, we present neutrino emissivities due to these processes calculated for typical profiles of core-collapsed supernovae. These novel neutrino emissivities are compared with the standard neutrino-emission mechanisms. We find that the electron-type neutrino emissivity due to electron capture on the deuteron is comparable to that on the proton in the deuteron abundant region. The electron-type antineutrino emissivity due to positron capture on the deuteron is much smaller than that on the neutron. The neutrino emissivity through deuteron formation is smaller than the conventional processes, but may be important in a situation where the nucleon-nucleon bremsstrahlung is important. The implications of the new channels involving deuterons for the supernova mechanism are discussed.

Nasu, S.; Nakamura, S. X.; Sumiyoshi, K.; Sato, T.; Myhrer, F.; Kubodera, K.

2015-03-01

10

Neutrino Emissivities from Deuteron-Breakup and Formation in Supernovae  

NASA Astrophysics Data System (ADS)

Recently it was pointed out that there are abundant light clusters, such as deuteron, triton and helium, in supernova environment. An interesting question is how much neutrino emissions from these light clusters affect supernova explosion mechanism. To address this question through a supernova simulation, neutrino emissivities from these light clusters are necessary input. The deuteron is the simplest cluster, and occupy a substantial portion of the light cluster abundance. Thus in this work, we study neutrino emissions from electron/positron capture on the deuteron and the nucleon-nucleon fusion processes in the surface region of a supernova core. We evaluate these weak processes using one-nucleon impulse current supplemented by two-nucleon exchange-currents, and nuclear wave functions generated by a high precision nucleon-nucleon potential. We present the neutrino emissivities from the deuteron calculated for typical profiles of core-collapsed supernovae. These novel neutrino emissivities are compared with the standard neutrino emission mechanisms.

Nakamura, Satoshi X.

2014-12-01

11

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

E-print Network

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

M. Beyer; G. Röpke; A. Sedrakian

1996-01-25

12

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

E-print Network

In an experiment with a 65 MeV/nucleon polarized deuteron beam on a liquid-deuterium target at KVI, several multi-body final states in deuteron-deuteron scattering were identified. For these measurements, a unique and advanced detection system, called BINA, 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.

A. Ramazani-Moghaddam-Arani; H. R. Amir-Ahmadi; A. D. Bacher; C. D. Bailey; A. Biegun; M. Eslami-Kalantari; I. Gašpari?; L. Joulaeizadeh; N. Kalantar-Nayestanaki; St. Kistryn; A. Kozela; H. Mardanpour; J. G. Messchendorp; A. M. Micherdzinska; H. Moeini; S. V. Shende; E. Stephan; E. J. Stephenson; R. Sworst

2010-12-20

13

Probing Vector Mesons in Deuteron Break-up Reactions  

E-print Network

We study vector meson photoproduction from the deuteron at high momentum transfer, accompanied by break-up of the deuteron into a proton and neutron. The large $-t$ involved allows one of the nucleons to be identified as struck, and the other as a spectator to the $\\gamma N\\rightarrow VN$ subprocess. Corrections to the plane wave impulse approximation involve final state interactions (FSIs) between the struck nucleon or the vector meson, either of which is energetic, with the slow spectator nucleon. In this regime, the eikonal approximation is valid, so is employed to calculate the cross-section for the reaction. Due to the high-energy nature of the FSIs, the maxima of the rescatterings are located at nearly transverse directions of the fast hadrons. This results in two peaks in the angular distribution of the spectator nucleon, each corresponding to either the $V$-$N$ or the $p$-$n$ rescattering. The $V$-$N$ peak provides a new means of probing the $V$-$N$ interaction. This is checked for near-threshold $\\phi$ and $J/\\Psi$ photoproduction reactions which demonstrate that the $V$-$N$ peak can be used to extract the largely unknown amplitudes of $\\phi$-$N$ and $J/\\Psi$-$N$ interactions. Two additional phenomena are observed when extending the calculation of $J/\\Psi$ photoproduction to the sub-threshold and high-energy domains. In the first case we observe overall suppression of FSI effects due to a restricted phase space for sub-threshold production in the rescattering amplitude. In the second, we observe cancellation of the $V$-$N$ rescattering amplitudes for vector mesons produced off of different nucleons in the deuteron.

Adam J. Freese; Misak M. Sargsian

2013-07-06

14

Treatment of the proton-proton Coulomb force in proton-deuteron breakup Faddeev calculations  

E-print Network

We extend our approach to incorporate the proton-proton (pp) Coulomb force into the three-nucleon (3N) Faddeev calculations from elastic proton-deuteron (pd) scattering to the breakup process. The main new ingredient is a 3-dimensional screened pp Coulomb t-matrix obtained by a numerical solution of the 3-dimensional Lippmann-Schwinger equation. We demonstrate numerically that the proton-deuteron breakup observables can be determined from the resulting on-shell 3N amplitudes increasing the screening radius. However, contrary to the pd elastic scattering, the screening limit exists only after renormalisation of the pp t-matrices.

H. Witala; R. Skibinski; J. Golak; W. Glockle

2009-06-17

15

Vector and Tensor Polarization Measurements for Deuteron-Proton and Deuteron-Neutron Quasifree Scattering Using the Polarized Deuteron + Deuteron Going to Deuteron + Proton + Neutron Breakup Reaction at 12 Mev  

NASA Astrophysics Data System (ADS)

Measurements of vector and tensor analyzing powers A_{y}, A_ {yy} and A_{zz} for dp and dn quasifree scattering (QFS) have been made using the vec d+dto d+p+n breakup reaction at the Triangle Universities Nuclear Laboratory. The experiment was conducted with a 12-MeV tensor-polarized deuteron beam incident on a gas cell filled with one bar deuterium. The momenta of two (deuteron-neutron, deuteron -proton or proton-neutron) of the three outgoing particles were measured simultaneously, thereby completely defining the reaction kinematics. Deuteron-proton coincidence data were taken at five laboratory angle pairs: (theta _{d},theta_{p}) = (+/-10.0^circ, mp10.0^circ), (+/-10.0, mp41.2 ^circ), (+/-17.0 ^circ,mp17.0 ^circ), (+/-17.0 ^circ,mp34.5 ^circ) and (+/-19.4 ^circ,mp19.4 ^circ). Deuteron-neutron and proton -neutron coincidence data were taken at three laboratory angle pairs: (theta_{d}, theta_{n}) = (theta _{n},theta_{n}) = (+/-17.0^ circ,mp17.0^circ ), (+/-17.0^ circ,mp34.5^circ ) and (+/-19.4^ circ,mp28.9^circ ). The angle pairs (theta_ {d},theta_{n}), (theta_{p},theta_ {n}) and (theta_ {d},theta_{p}) were chosen such that the reaction would be well-suited for observing dn and dp QFS. Deuteron-proton coincidence data were sorted into two-dimensional (2D) spectra of deuteron energy versus proton energy, while proton-neutron and deuteron -neutron data were sorted into 2D spectra of neutron time -of-flight versus proton energy and deuteron energy, respectively. Each 2D spectrum was projected onto the kinematically allowed locus. Analyzing powers were computed as a function of arc length S along the locus for A_{y }, A_{yy} and A_{zz}. Since four-nucleon calculations involving polarization observables for the vec d+dto d+p+n breakup reaction are not yet available, the data are compared to Impulse-Approximation (IA) calculations. The IA calculations included off-the-energy-shell deuteron -nucleon (dN) amplitudes as well as on-the-energy-shell dN amplitudes and also included the coherent addition of scattering amplitudes for both target breakup and projectile breakup. The IA calculations fail to reproduce many of the details in the measured data, indicating that the vec d+dto d+p+n breakup process is inherently more complicated at 12 MeV than the single scattering assumption which forms the basis for the IA. The possibility of using the vec d+dto d+p+n breakup reaction to examine charge symmetry breaking in the nucleon-nucleon interaction is also explored. Some differences in the analyzing powers for charge symmetric processes were observed. Detailed examination of the breakup process suggests that while some of the differences can be attributed to electromagnetic effects, other differences cannot. These unexplained differences could be a signature of charge-symmetry breaking. The development of a computer code to conduct four-nucleon calculations using a realistic microscopic approach for the vec d+dto d+p+n reaction has recently been initiated by A. C. Fonseca of Lisbon. The forthcoming calculations will form the basis for interpreting the present data and stimulating further studies of nucleon-nucleon interactions through this breakup process.

Felsher, Paul Daniel

1991-02-01

16

On reaction mechanisms involved in the deuteron-induced surrogate reactions  

NASA Astrophysics Data System (ADS)

An extended analysis of the nuclear reaction mechanisms involved within deuteron interaction with nuclei, namely the breakup, stripping, pick-up, pre-equilibrium emission, and evaporation from fully equilibrated compound nucleus, is presented in order to highlight the importance of the direct mechanisms still neglected in the analysis of deuteron-induced surrogate reactions. Particularly, the dominance of the breakup mechanism at low energies around the Coulomb barrier should be considered in the case of (d,x) surrogate reactions on actinide target nuclei.

Avrigeanu, M.; Avrigeanu, V.; M?n?ilescu, C.

2015-02-01

17

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

18

Neutron-deuteron breakup reaction as a tool for studying neutron-neutron interactions  

SciTech Connect

An analysis of the most recent data on the reaction nd {yields} pnn revealed a serious discrepancy between theoretical predictions and cross sections measured for this reaction in various configurations where the role of neutron-neutron interactions is important. In view of this, it seems necessary both to develop theoretical approaches and to obtain new experimental data. For this purpose, a setup for studying the neutron-deuteron breakup reaction was created at the Institute for Nuclear Research on the basis of the neutron beam in the RADEX channel and deuterium targets. This facility makes it possible to perform experiments over a broad region of primary-neutron energies (10-60 MeV) and in various (final-state interaction, quasifree scattering, and spatial-star) configurations. Preliminary results of the respective experiment were obtained for configurations of final-state neutron-neutron interaction and quasifree neutron-neutron scattering.

Konobeevski, E. S., E-mail: konobeev@inr.ru; Zuyev, S. V.; Mordovskoy, M. V.; Potashev, S. I.; Sharapov, I. M. [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation)] [Russian Academy of Sciences, Institute for Nuclear Research (Russian Federation)

2013-11-15

19

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

20

Investigation of the Three-Nucleon System Dynamics in the Deuteron-Proton Breakup Reaction  

NASA Astrophysics Data System (ADS)

Precise and large sets of cross section, vector A x , A y and tensor A xx , A xy , A yy analyzing power data for the 1 H( d, pp) n breakup reactions were measured at 100 and 130 MeV deuteron beam energies with the SALAD and BINA detectors at KVI and the Germanium Wall setup at FZ-Jülich. Results are compared with various theoretical approaches which model the three-nucleon system dynamics. The cross section data reveal a sizable three-nucleon force (3NF) and Coulomb force influence. In case of the analyzing powers very low sensitivity to these effects was found and the data are well describe by 2N models only. For A xy at 130 MeV, serious disagreements were observed when 3NF models are included in the calculations.

Ciepa?, I.; K?os, B.; Kistryn, St.; Stephan, E.; Biegun, A.; Bodek, K.; Deltuva, A.; Epelbaum, E.; Eslami-Kalantari, M.; Fonseca, A. C.; Golak, J.; Jha, V.; Kalantar-Nayestanaki, N.; Kamada, H.; Khatri, G.; Kirillov, Da.; Kirillov, Di.; Kliczewski, St.; Kozela, A.; Kravcikova, M.; Machner, H.; Magiera, A.; Martinska, G.; Messchendorp, J.; Nogga, A.; Parol, W.; Ramazani-Moghaddam-Arani, A.; Roy, B. J.; Sakai, H.; Sekiguchi, K.; Sitnik, I.; Siudak, R.; Skibi?ski, R.; Sworst, R.; Urban, J.; Wita?a, H.; Zejma, J.

2014-08-01

21

Analyzing power measurements in pion-deuteron breakup at intermediate energies  

NASA Astrophysics Data System (ADS)

As part of an experimental study of the ?NN system, the pion-deuteron breakup reaction ?+d-->-->pn?+ was investigated at intermediate energies. Distributions of the vector analyzing power iT11 versus outgoing proton momentum Pp are presented for 36 ?p angle pairs in the range of scattering angles 20°<=?p<=51°, 62°<=??<=124° at 228 and 134 MeV. These include 7 previously unmeasured angle pairs at 228 MeV and 20 new pairs at 134 MeV. In all regions of overlap with previous measurements, there is excellent agreement. There is generally excellent agreement with relativistic Faddeev predictions, except in the np final-state interaction region at 228 MeV. This is in contrast to the cross-section measurements, which are not well described by the theory.

Yeomans, D. M.; Mathie, E. L.; Huber, G. M.; Lolos, G. J.; Naqvi, S. I.; Pafilis, V.; Jones, G.; Sevior, M.; Trelle, R. P.; Weber, P.; Tacik, R.; Healey, D.; Ottewell, D. F.; Smith, G. R.; Wait, G.; Garcilazo, H.; Humphrey, D. L.

1995-11-01

22

Studies of the Three-Nucleon System Dynamics in the Deuteron-Proton Breakup Reaction  

NASA Astrophysics Data System (ADS)

One of the most important goals of modern nuclear physics is to contruct nuclear force model which properly describes the experimental data. To develop and test predictions of current models the breakup 1H(overrightarrow d, pp)n reaction was investigated experimentally at 100 and 130 MeV deuteron beam energies. Rich set of data for cross section, vector and tensor analyzing powers was obtained with the use of the SALAD and BINA detectors at KVI and Germanium Wall setup at FZ-Jülich. Results are compared with various theoretical approaches which describe the three-nucleon (3N) system dynamics. For correct description of the cross section data both, three-nucleon force (3NF) and Coulomb force, have to be included into calculations and influence of those ingredients is seizable at specific parts of the phase space. In case of the vector analyzing powers very low sensitivity to any effects beyond nucleon-nucleon interaction was found. At 130 MeV, the Axy data are not correctly described when 3NF models are included into calculations.

Ciepa?, I.; K?os, B.; Stephan, E.; Kistryn, St.; Biegun, A.; Bodek, K.; Deltuva, A.; Epelbaum, E.; Eslami-Kalantari, M.; Fonseca, A. C.; Golak, J.; Jha, V.; Kalantar-Nayestanaki, N.; Kamada, H.; Khatri, G.; Kirillov, Da.; Kirillov, Di.; Kliczewski, St.; Kozela, A.; Kravcikova, M.; Machner, H.; Magiera, A.; Martinska, G.; Messchendorp, J.; Nogga, A.; Parol, W.; Ramazani-Moghaddam-Arani, A.; Roy, B. J.; Sakai, H.; Sekiguchi, K.; Sitnik, I.; Siudak, R.; Skibi?ski, R.; Sworst, R.; Urban, J.; Wita?a, H.; Zejma, J.

2014-03-01

23

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

PubMed

Inclusive inelastic electron scattering off the deuteron under 180 degrees has been studied at the S-DALINAC close to the breakup threshold at momentum transfers q=0.27 fm;{-1} and 0.74 fm;{-1} with good energy resolution sufficient to map in detail the spin flip M1 response, which governs the starting reaction pn-->dgamma of big-bang nucleosynthesis over most of the relevant temperature region. Results from potential model calculations and (for q=0.27 fm;{-1}) from pionless nuclear effective field theory are in excellent agreement with the data. PMID:18518283

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

2008-05-01

24

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

25

Electromagnetic deuteron form factors in point form relativistic quantum mechanics  

E-print Network

A study of electromagnetic structure of the deuteron in the framework of relativistic quantum mechanics is presented. The deuteron form factors dependencies on the transferred 4-momentum Q are calculated. We compare results obtained with different realistic deuteron wave functions stemming from Nijmegen-I, Nijmegen-II, JISP16, CD-Bonn, Paris and Moscow (with forbidden states) potentials. A nucleon form factor parametrization consistent with modern experimental analysis was used as an input data.

N. A. Khokhlov

2015-03-10

26

Electromagnetic deuteron form factors in point form relativistic quantum mechanics  

E-print Network

A study of electromagnetic structure of the deuteron in the framework of relativistic quantum mechanics is presented. The deuteron form factors dependencies on the transferred 4-momentum Q are calculated. We compare results obtained with different realistic deuteron wave functions stemming from Nijmegen-I, Nijmegen-II, JISP16, CD-Bonn, Paris and Moscow (with forbidden states) potentials. A nucleon form factor parametrization consistent with modern experimental analysis was used as an input data.

Khokhlov, N A

2015-01-01

27

Analysis of experimental data on doublet neutron-deuteron scattering at energies below the deuteron-breakup threshold on the basis of the pole approximation of the effective-range function  

SciTech Connect

On the basis of the Bargmann representation of the S matrix, the pole approximation is obtained for the effective-range function k cot {delta}. This approximation is optimal for describing the neutron-deuteron system in the doublet spin state. The values of r{sub 0} = 412.469 fm and v{sub 2} = -35 495.62 fm{sup 3} for the doublet low-energy parameters of neutron-deuteron scattering and the value of D = 172.678 fm{sup 2} for the respective pole parameter are deduced by using experimental results for the triton binding energy E{sub T}, the doublet neutron-deuteron scattering length a{sub 2}, and van Oers-Seagrave phase shifts at energies below the deuteron-breakup threshold. With these parameters, the pole approximation of the effective-range function provides a highly precise description (the relative error does not exceed 1%) of the doublet phase shift for neutron-deuteron scattering at energies below the deuteron-breakup threshold. Physical properties of the triton in the ground (T) and virtual (v) states are calculated. The results are B{sub v} = 0.608 MeV for the virtuallevel position and C{sub T}{sup 2} = 2.866 and C{sub v}{sup 2} = 0.0586 for the dimensionless asymptotic normalization constants. It is shown that, in the Whiting-Fuda approximation, the values of physical quantities characterizing the triton virtual state are determined to a high precision by one parameter, the doublet neutron-deuteron scattering length a{sub 2}. The effective triton radii in the ground ({rho}{sub T} = 1.711 fm) and virtual ({rho}{sub v} = 74.184 fm) states are calculated for the first time.

Babenko, V. A.; Petrov, N. M., E-mail: pet@online.com.ua [National Academy of Sciences of Ukraine, Bogolyubov Institute for Theoretical Physics (Ukraine)

2008-01-15

28

Analysis of experimental data on doublet neutron-deuteron scattering at energies below the deuteron-breakup threshold on the basis of the pole approximation of the effective-range function  

NASA Astrophysics Data System (ADS)

On the basis of the Bargmann representation of the S matrix, the pole approximation is obtained for the effective-range function k cot ?. This approximation is optimal for describing the neutron-deuteron system in the doublet spin state. The values of r 0 = 412.469 fm and v 2 = -35 495.62 fm3 for the doublet low-energy parameters of neutron-deuteron scattering and the value of D = 172.678 fm2 for the respective pole parameter are deduced by using experimental results for the triton binding energy E T , the doublet neutron-deuteron scattering length a 2, and van Oers-Seagrave phase shifts at energies below the deuteron-breakup threshold. With these parameters, the pole approximation of the effective-range function provides a highly precise description (the relative error does not exceed 1%) of the doublet phase shift for neutron-deuteron scattering at energies below the deuteron-breakup threshold. Physical properties of the triton in the ground ( T) and virtual ( v) states are calculated. The results are B v = 0.608 MeV for the virtuallevel position and C {/T 2} = 2.866 and C {/v 2} = 0.0586 for the dimensionless asymptotic normalization constants. It is shown that, in the Whiting-Fuda approximation, the values of physical quantities characterizing the triton virtual state are determined to a high precision by one parameter, the doublet neutron-deuteron scattering length a 2. The effective triton radii in the ground ( ? T = 1.711 fm) and virtual ( ? v = 74.184 fm) states are calculated for the first time.

Babenko, V. A.; Petrov, N. M.

2008-01-01

29

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

30

Complete Sets of Polarization Observables in Electromagnetic Deuteron Break-up  

E-print Network

For deuteron photo- and electrodisintegration the selection of complete sets of polarization observables is discussed in detail by applying a recently developed new criterion for the check of completeness of a chosen set of observables. The question of ambiguities and their resolution by considering additional observables is discussed for a numerical example, for which the role of experimental uncertainties is also investigated. Furthermore, by inversion of the expressions of the observables as hermitean forms in the $t$-matrix elements a bilinear term of the form $t_{j'}^*t_j$ can be given as a complex linear form in the observables from which an explicit solution for $t_j$ in terms of observables can be obtained. These can also be used to select sets of observables for the explicit representation of the $t$-matrix.

Hartmuth Arenhoevel; Winfried Leidemann; Edward L. Tomusiak

1999-05-14

31

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

SciTech Connect

High-precision data for vector and tensor analyzing powers for the {sup 1}H(d-vector,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 A{sub xy} such discrepancies usually appear, or are enhanced, when model 3N forces, TM99 or Urbana, are included. Problems of all theoretical approaches with describing A{sub xx} and A{sub yy} are limited to very small kinematical regions, usually characterized by the lowest energy of the relative motion of the two protons.

Stephan, E.; Biegun, A.; Klos, B.; Micherdzinska, A.; Zipper, W. [Institute of Physics, University of Silesia, PL-40007 Katowice (Poland); Kistryn, St.; Sworst, R.; Bodek, K.; Ciepal, I.; Golak, J.; Skibinski, R.; Witala, H.; Wronska, A.; Zejma, J. [Institute of Physics, Jagiellonian University, PL-30059 Krakow (Poland); Deltuva, A. [Centro de Fisica Nuclear da Universidade de Lisboa, P-1649-003 Lisboa (Portugal); Epelbaum, E. [Institute fuer Theoretische Physik II, Ruhr-Universitaet Bochum, D-44780 Bochum (Germany); Fonseca, A. C. [Centro de Fisica Nuclear, Universidade de Lisboa, P-1649-003 Lisboa (Portugal); Kalantar-Nayestanaki, N.; Kis, M.; Mahjour-Shafiei, M. [Kernfysisch Versneller Instituut, University of Groningen, NL-9747 AA Groningen (Netherlands)

2010-07-15

32

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

E-print Network

The pd break-up amplitude in the Faddeev scheme is calculated by employing a three-dimensional method without partial wave decomposition (PWD). In a 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.

I. Fachruddin; Ch. Elster; W. Gloeckle

2002-11-22

33

Non-nucleon degrees of freedom in the deuteron from the d(\\vec e,e'\\vec p,)n break-up  

E-print Network

We analyzed contribution of quark degrees of freedom in the deuteron to the longitudinal, P_z', and transverse, P_x', polarizations of the proton in the d(\\vec e,e'\\vec p)n break-up. It is demonstrated that such effects work in correct direction to explain experimental data. We predict that the polarizations should change qualitatively behavior at p_m >200 MeV/c, (i) the polarizations become strongly dependent on the out-of-plain angle and (ii) there appears a structure in the both polarizations at p_m ~200 MeV/c.

Alexander Kobushkin; Yurij Kutafin

2009-03-13

34

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

35

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

36

Formation of droplets and bubbles in a microfluidic T-junction--scaling and mechanism of break-up{  

E-print Network

Formation of droplets and bubbles in a microfluidic T-junction--scaling and mechanism of break-up in microfluidic T-junction geometries. At low capillary numbers break-up is not dominated by shear stresses: experimental results support the assertion that the dominant contribution to the dynamics of break-up arises

Prentiss, Mara

37

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

38

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

39

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 T cnica 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 micrometers, and airfoil velocities of 70 and 90 meters/second.

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

2012-01-01

40

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

41

Mechanism of ternary breakup in the reaction Au197+Au197 at 15A MeV  

NASA Astrophysics Data System (ADS)

The mechanism of the ternary breakup of the very heavy system Au197+Au197 at an energy of 15A MeV has been studied by using the improved quantum molecular dynamics model. The calculation results reproduce the characteristic features in ternary breakup events explored in a series of experiments; i.e., the masses of three fragments are comparable in size and the very fast, nearly collinear breakup of the colliding system is dominant in the ternary breakup events. Further, the evolution of the time scales of different ternary reaction modes and the behavior of mass distributions of three fragments with impact parameters are studied. The time evolution of the configurations of the composite reaction systems is also studied. We find that for most of the ternary breakup events with the features found in the experiments, the configuration of the composite system has two-preformed-neck shape. The study shows that those ternary breakup events having the characteristic features found in the experiments happen at relatively small impact parameter reactions, but not at peripheral reactions. The ternary breakup reaction at peripheral reactions belongs to binary breakup with a neck emission.

Tian, Junlong; Wu, Xizhen; Li, Zhuxia; Zhao, Kai; Zhang, Yingxun; Li, Xian; Yan, Shiwei

2010-11-01

42

Break-up mechanisms in heavy ion collisions at low energies  

E-print Network

We investigate reaction mechanisms occurring in heavy ion collisions at low energy (around 20 MeV/u). In particular, we focus on the competition between fusion and break-up processes (Deep-Inelastic and fragmentation) in semi-peripheral collisions, where the formation of excited systems in various conditions of shape and angular momentum is observed. Adopting a Langevin treatment for the dynamical evolution of the system configuration, described in terms of shape observables such as quadrupole and octupole moments, we derive fusion/fission probabilities, from which one can finally evaluate the corresponding fusion and break-up cross sections. The dependence of the results on shape, angular momentum and excitation energy is discussed.

L. Shvedov; M. Colonna; M. Di Toro

2010-03-10

43

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

44

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

NASA Astrophysics Data System (ADS)

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

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

2011-09-01

45

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

NASA Astrophysics Data System (ADS)

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

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

2011-05-01

46

Catastrophic ice-shelf break-up by an ice-shelf-fragment-capsize mechanism  

NASA Astrophysics Data System (ADS)

Two disintegration events leading to the loss of Larsen A and B ice shelves, Antarctic Peninsula, in 1995 and 2002, respectively,proceeded with extreme rapidity (order of several days) and reduced an extensive, seemingly integrated ice shelf to a jumble of small fragments. These events strongly correlate with warming regional climate and accumulation of surface meltwater, supporting a hypothesis that meltwater-induced propagation of pre-existing surface crevasses may have initiated ice-shelf fragmentation.Weaddress here an additional, subsequent mechanism that may sustain and accelerate the ice-shelf break-up once it begins.The proposed mechanism involves the coherent capsize of narrow (less than thickness) ice-shelf fragments by rolling 90° in a direction toward, or away from, the ice front. Fragment capsize liberates gravitational potential energy, forces open ice-shelf rifts and contributes to further fragmentation of the surrounding ice shelf.

Macayeal, Douglas R.; Scambos, Ted A.; Hulbe, Christina L.; Fahnestock, Mark A.

47

Tectonic Transformation and Dynamic Mechanism of Break-up Unconformity in the Pearl River Mouth Basin  

NASA Astrophysics Data System (ADS)

Research on break-up unconformity (B.U.) is significant for the basins evolution and deep dynamics of northern continental margin of South China Sea (SCS). Based on the integrated analysis of seismic-drilling-logging data, by giving insight to the synsedimentary tectonics and their controls on sedimentation, this study aims to reveal the tectonic transformation and dynamic mechanism of B.U. in the Pearl River Mouth Basin (PRMB). Most faults oriented NEE-EW and controlled a series of small separate rifted sub-basins below the B.U., fluvial or lacustrine environment predominated. A new set of faults with NWW-NW direction were developed above the B.U., surrounding the Baiyun sag and mostly dipping towards the sag center. The Baiyun sag instead of a number of separate sub-basins became the major depocenter and filled marine-continental transitional facies. According to the faults geometries, we suggest that nearly SSE extensional stress field strongly controlled the development of the small separate rifted sub-basins underlying the B.U., and SSW extensional stress field resulted in the formation of new faults set over the B.U. The evidence of regional and biostratigraphical correlation indicated that the B.U. age is 30Ma in the PRMB, which is consistent with the time of initial spreading of the SCS. Therefore this B.U. should be influenced by the continental breakup and SCS's open. On this basis, dynamic mechanisms associated with tectonic transformation at 30Ma may be put forward: (1) Before 30Ma (pre-breakup stage), due to the spreading directions parallel to the general trend of the northern SCS margin, the PRMB was controlled by SSE stretching; (2) When seafloor spreading began, the PRMB on the northern margin entered the transitional stage from rift to drift, suffering lithosphere thinning and mantle upwelling. In this context, the Baiyun sag occur abnormal subsidence, what is more, high-deposition-rate sediment derived from the continental slope accumulated here, eventually the Baiyun sag deformed strongly driven by gravitational potential, and developed plenty of faults surrounding and dipping toward the sag center.

Zhang, Cuimei; Sun, Zhen; Pang, Xiong; Yan, Chengzhi; Zhao, Zhongxian; Li, Pengchun; Zhang, Yunfan

2013-04-01

48

Tectonic transformation and dynamic mechanism of break-up unconformity in the Pearl River Mouth Basin  

NASA Astrophysics Data System (ADS)

Research on break-up unconformity (B.U.) is significant for the basins evolution and deep dynamics of northern continental margin of South China Sea (SCS). Based on the integrated analysis of seismic-drilling-logging data, by giving insight to the synsedimentary tectonics and their controls on sedimentation, this study aims to reveal the tectonic transformation and dynamic mechanism of B.U. in the Pearl River Mouth Basin (PRMB). Most faults oriented NEE-EW and controlled a series of small separate rifted sub-basins below the B.U., fluvial or lacustrine environment predominated. A new set of faults with NWW-NW direction were developed above the B.U., surrounding the Baiyun sag and mostly dipping towards the sag center. The Baiyun sag instead of a number of separate sub-basins became the major depocenter and filled marine-continental transitional facies. According to the faults geometries, we suggest that nearly SSE extensional stress field strongly controlled the development of the small separate rifted sub-basins underlying the B.U., and SSW extensional stress field resulted in the formation of new faults set over the B.U. The evidence of regional and biostratigraphical correlation indicated that the B.U. age is 30Ma in the PRMB, which is consistent with the time of initial spreading of the SCS. Therefore this B.U. should be influenced by the continental breakup and SCS's open. On this basis, dynamic mechanisms associated with tectonic transformation at 30Ma may be put forward: (1) Before 30Ma (pre-breakup stage), due to the spreading directions parallel to the general trend of the northern SCS margin, the PRMB was controlled by SSE stretching; (2) When seafloor spreading began, the PRMB on the northern margin entered the transitional stage from rift to drift, suffering lithosphere thinning and mantle upwelling. In this context, the Baiyun sag occur abnormal subsidence, what is more, high-deposition-rate sediment derived from the continental slope accumulated here, eventually the Baiyun sag deformed strongly driven by gravitational potential, and developed plenty of faults surrounding and dipping toward the sag center.

Zhang, C.; Sun, Z.; Pang, X.; Yan, C.; Zhao, Z.; Li, P.; Zhang, Y.

2011-12-01

49

Deutron Break-Up: Theoretical Description of Polarization Observables in Stapp formalism  

E-print Network

The vector and tensor analyzing powers as well as the polarization of the outgoing proton are calculated for the exclusive deuteron break-up reaction $\\vec{d}p \\to \\vec{p}pn$ at a deuteron beam energy of 2 GeV. Two component covariant formalism of Stapp has been used to have the completely Lorentz invariant model. In addition to the Impulse Approximation the nucleon-nucleon double-scattering and delta-excitation mechanism have been added coherently. Good agreement with the precise data obtained at Saclay is achieved.

O. G. Grebenyuk

2005-11-28

50

Fracture Mechanical Analysis of Frost Wedging in Ice Shelves as Break-Up Mechanism  

NASA Astrophysics Data System (ADS)

Disintegration events in ice shelves have been the subject of extensive investigations in the past years, however comprehensive explanations applicable to a majority of events are still missing. A popular assumption made by Scambos et al. (2000) [1] links disintegration events to a general thinning of the ice shelf in conjunction with growing melt-water ponds leading to hydro fractures. This explanation seems reasonable for break-up events that happened in Antarctic summers. Large parts of the Wilkins Ice Shelf, however broke-up in fall and winter periods. Therefore, the aim of the present study is to analyse the possibility of frost wedging of water filled surface crevasses in an ice shelf as a source of break-up events. Configurational forces are used to assess crack criticality. The simulations are performed on a 2-dimensional single crack with a mode-I type load, body forces and additional crack-face pressure due to freezing of the water. Depth-dependent density profiles are considered. The relevant parameters, Young's modulus, Poisson's ratio and external loading are obtained from literature, remote sensing data analysis and modelling of the ice dynamics. The investigation is performed using the finite element software COMSOL. The simulations show that in comparison to water filled crevasses without ice, thin layers of frozen water may lead to a decreasing criticality at the crack tip as long as the ice 'bridge' is allowed to take tensile loads. An increasing crack criticality can be seen for thicker layers of ice. The results are compared to findings from previous finite element analyses of dry and water filled cracks as presented in Plate et al. (2012) [2]. [1] Scambos, T., Hulbe, C., Fahnestock, M., & Bohlander, J. (2000). The link between climate warming and break-up of ice shelves in the Antarctic Peninsula. Journal of Glaciology, 46(154), 516-530. [2] Plate, C., Müller, R., Humbert, A., & Gross, D. (2012). Evaluation of the criticality of cracks in ice shelves using finite element simulations. The Cryosphere, 6(5), 973-984.

Plate, Carolin; Humbert, Angelika; Gross, Dietmar; Müller, Ralf

2013-04-01

51

Electrodisintegration of polarized deuterons  

SciTech Connect

Dependences of the azimuthal and target asymmetries in the breakup of polarized deuterons by unpolarized electrons on the choice of the deuteron electromagnetic (EM) current model and final-state interaction (FSI) effects are investigated. Possibilities for separation of the structure functions which determine these observables are discussed. Results of the calculations are compared with available data. It has been shown that FSI plays an important role in formation of the asymmetries. In the quasifree region some of them depend considerably on the neutron electric form factor and on the spin-orbit EM interaction with nucleon. The tensor target asymmetries [ital T][sub 20] and [ital T][sub 22] calculated for [sup 2][rvec H]([ital e],[ital pn])[ital e][prime] under kinematic conditions of the experiment with the electron storage ring VEPP-3 in Novosibirsk have been found to be very sensitive to the meson exchange current contributions.

Mel'nik, Y.P.; Shebeko, A.V. (Kharkov Institute of Physics and Technology, 310108 Kharkov (Ukraine))

1993-09-01

52

Explosive break-up of Larsen Ice Shelf, Antarctica, by a meltwater-triggered iceberg capsize mechanism  

NASA Astrophysics Data System (ADS)

Two disintegration events leading to the loss of Larsen A and B ice shelves in 1995 and 2002, respectively, proceeded with extreme rapidity (order several days) and reduced integrated ice shelf to a jumble of small iceberg fragments. These events strongly correlate with warming regional climate and accumulation of surface melt water, supporting the hypothesis that meltwater induced propagation of pre-existing surface crevasses may have started ice-shelf fragmentation. What we address in this study is not the crevasse propagation process that triggers disintegration, but rather a mechanism that may sustain the ice-shelf break-up once it begins. The proposed mechanism involves the coherent capsize of narrow (less than thickness) ice-shelf fragments by rolling 90° in a direction toward the ice front. We envision such fragments as being pieces of ice shelf liberated when two surface or basal crevasses oriented across the pre break-up flow direction suddenly cleave the entire ice thickness, e.g., as a result of meltwater crevasse wedging. Fragment capsize liberates gravitational potential energy and creates forces that wedge open ice-shelf rifts (void space containing the fragment). We speculate that the wedging forces so created may stimulate further fragmentation of the ice shelf and thereby contribute to its sudden disintegration. The process we propose is analagous to the overflow of a champagne bottle that has been opened after having been vigorously shaken. In the analogy, bubbles play the role of ice-shelf voids (rifts) that contain floating ice fragments that can capsize, and CO2 gas within the bubbles plays the role of capsizing ice fragments that create wedging forces tending to widen the rifts that contain them. Observational support for our proposed mechanism is provided by post-break-up MODIS (visible) satellite imagery that reveals formerly englacial debris exposed at the surface and small, blue-colored sub-pixel-sized icebergs that have rolled onto their sides.

Macayeal, D. R.; Hulbe, C. L.; Scambos, T. A.; Fahnestock, M. A.

2002-12-01

53

Asymmetry Energy Effects on Reaction Break-up Mechanisms Near the Fermi Energy  

NASA Astrophysics Data System (ADS)

Heavy Ion Collisions play an important role in probing the density dependence of the asymmetry energy by providing a unique tool to probe nuclear interactions away from saturation. Lower energy reactions (~10-15A MeV) provide a means of probing around and below normal nuclear density. In particular, these collisions can provide a sensitive means of probing the interaction and possibly the asymmetry terms of the nuclear Equation of State. Simulations of 124Sn+64Ni using Constrained Molecular Dynamics and Stochastic Mean Field calculations, at different asymmetry energies, have been used to study the asymmetry energy dependence of projectile-like fragment break-up channels as well as the mass correlations of the heaviest fragments. The results of these simulations present the possibility of developing an experimental probe for measuring the density dependence of the asymmetry energy using picosecond time resolution time of flight spectroscopy in a multi-detector array.

Cammarata, Paul J.; McIntosh, Alan B.; Colonna, Maria; May, Larry W.; Heilborn, Lauren; Mabiala, Justin; Raphelt, Andrew; Zarrella, Andrew; Yennello, Sherry J.

2013-03-01

54

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

55

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

56

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

57

Low and medium energy deuteron-ind ced reactions on $^{63,65}$Cu nuclei  

E-print Network

The activation cross sections of (d,p), (d,2n), (d,3n), and (d,2p) reactions on 63,65Cu were measured in the energy range from 4 to 20 MeV using the stacked-foils technique. Then, following the available elastic-scattering data analysis that provided the optical potential for reaction cross sections calculations, an increased effort has been devoted to the breakup mechanism, the direct reaction stripping, and the 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 mechanisms account, next to the simultaneous analysis of the elastic-scattering and reaction data.

Simeckova, E; Honusek, M; Stefánik, M; Fischer, U; Simakov, S P; Forrest, R A; Koning, A J; Sublet, J -C; Avrigeanu, M; Roman, F L; Avrigeanu, V

2011-01-01

58

Low and medium energy deuteron-ind ced reactions on $^{63,65}$Cu nuclei  

E-print Network

The activation cross sections of (d,p), (d,2n), (d,3n), and (d,2p) reactions on 63,65Cu were measured in the energy range from 4 to 20 MeV using the stacked-foils technique. Then, following the available elastic-scattering data analysis that provided the optical potential for reaction cross sections calculations, an increased effort has been devoted to the breakup mechanism, the direct reaction stripping, and the 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 mechanisms account, next to the simultaneous analysis of the elastic-scattering and reaction data.

E. Simeckova; P. Bém; M. Honusek; M. Stefánik; U. Fischer; S. P. Simakov; R. A. Forrest; A. J. Koning; J. -C. Sublet; M. Avrigeanu; F. L. Roman; V. Avrigeanu

2011-06-24

59

Low and medium energy deuteron-induced reactions on Cu63,65 nuclei  

NASA Astrophysics Data System (ADS)

The activation cross sections of (d,p), (d,2n), (d,3n), and (d,2p) reactions on Cu63,65 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.

Šime?ková, E.; Bém, P.; Honusek, M.; Štefánik, M.; Fischer, U.; Simakov, S. P.; Forrest, R. A.; Koning, A. J.; Sublet, J.-C.; Avrigeanu, M.; Roman, F. L.; Avrigeanu, V.

2011-07-01

60

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

61

Role of virtual break-up of projectile in astrophysical fusion reactions  

E-print Network

We study the effect of virtual Coulomb break-up, commonly known as the dipole polarizability, of the deuteron projectile on the astrophysical fusion reaction 3He(d,p)4He. We use the adiabatic approximation to estimate the potential shift due to the E1 transition to the continuum states in the deuteron, and compute the barrier penetrability in the WKB approximation. We find that the enhancement of the penetrability due to the deuteron break-up is too small to resolve the longstanding puzzle observed in laboratory measurements that the electron screening effect is surprisingly larger than theoretical prediction based on an atomic physics model. The effect of the 3He break-up in the 3He(d,p)4He reaction, as well as the 7Li break-up in the 7Li(p,alpha)4He reaction is also discussed.

K. Hagino; M. S. Hussein; A. B. Balantekin

2003-07-09

62

Low-energy deuteron-induced reactions on 93Nb  

NASA Astrophysics Data System (ADS)

The activation cross sections of (d,p), (d,2n), (d,2np+nd+t), (d,2n?), and (d,p?) reactions on 93Nb were measured in the energy range from 1 to 20 MeV using the stacked-foil technique. Then, within a simultaneous analysis of elastic scattering and reaction data, the available elastic-scattering data analysis was carried out in order to obtain the optical potential for reaction cross-section calculations. Particular attention was paid to the description of the breakup mechanism and direct reaction stripping and pick-up, followed by pre-equilibrium and compound-nucleus calculations. The measured cross sections as well as all available deuteron activation data of 93Nb were compared with results of local model calculations carried out using the codes fresco and stapre-h and both default and particular predictions of the code talys-1.4 and tendl-2012-evaluated data.

Avrigeanu, M.; Avrigeanu, V.; Bém, P.; Fischer, U.; Honusek, M.; Koning, A. J.; Mrázek, J.; Šime?ková, E.; Štefánik, M.; Závorka, L.

2013-07-01

63

Surviving Atmospheric Spacecraft Breakup  

NASA Technical Reports Server (NTRS)

In essence, to survival a spacecraft breakup an animal must not experience a lethal event. Much as with surviving aircraft breakup, dissipation of lethal forces via breakup of the craft around the organism is likely to greatly increase the odds of survival. As spacecraft can travel higher and faster than aircraft, it is often assumed that spacecraft breakup is not a survivable event. Similarly, the belief that aircraft breakup or crashes are not survivable events is still prevalent in the general population. As those of us involved in search and rescue know, it is possible to survive both aircraft breakup and crashes. Here we make the first report of an animal, C. elegans, surviving atmospheric breakup of the spacecraft supporting it and discuss both the lethal events these animals had to escape and the implications implied for search and rescue following spacecraft breakup.

Szewczyk, Nathaniel J.; Conley, Catharine A.

2003-01-01

64

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

65

Note on Breakup Densities in Fragmentation  

E-print Network

This note elaborates the procedures involved in the derivation of breakup densities in nuclear fragmentation. It is stressed that the formalism employed in the analysis served only as a spectral fitting function and does not imply any specific reaction mechanism.

V. E. Viola

2007-05-02

66

Surviving atmospheric spacecraft breakup  

NASA Technical Reports Server (NTRS)

Spacecraft travel higher and faster than aircraft, making breakup potentially less survivable. As with aircraft breakup, the dissipation of lethal forces via spacecraft breakup around an organism is likely to greatly increase the odds of survival. By employing a knowledge of space and aviation physiology, comparative physiology, and search-and-rescue techniques, we were able to correctly predict and execute the recovery of live animals following the breakup of the space shuttle Columbia. In this study, we make what is, to our knowledge, the first report of an animal, Caenorhabditis elegans, surviving the atmospheric breakup of the spacecraft that was supporting it and discuss both the lethal events these animals had to escape and the implications for search and rescue following spacecraft breakup.

Szewczyk, Nathaniel J.; McLamb, William

2005-01-01

67

Muon Capture on the Proton and Deuteron  

E-print Network

By measuring the lifetime of the negative muon in pure protium (hydrogen-1), the MuCap experiment determines the rate of muon capture on the proton, from which the proton's pseudoscalar coupling g_p may be inferred. A precision of 15% for g_p has been published; this is a step along the way to a goal of 7%. This coupling can be calculated precisely from heavy baryon chiral perturbation theory and therefore permits a test of QCD's chiral symmetry. Meanwhile, the MuSun experiment is in its final design stage; it will measure the rate of muon capture on the deuteron using a similar technique. This process can be related through pionless effective field theory and chiral perturbation theory to other two-nucleon reactions of astrophysical interest, including proton-proton fusion and deuteron breakup.

Frederick Gray

2008-08-11

68

Experimental Investigation of the Few-Nucleon Dynamics in Deuteron-Deuteron Collision at 160 MeV  

NASA Astrophysics Data System (ADS)

An experiment, with unpolarized deuteron beam of 160 MeV impinging on liquid deuterium target, was carried out using BINA detector at KVI, in Groningen, the Netherlands. Data were collected for the purpose of obtaining high precision differential cross-section for the deuteron break-up reaction. The elastic scattering data were also collected alongside for the purpose of cross-section normalization. We present here a sample of the un-normalised cross-section for the three-body final state (dd?dpn) reaction.

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

2014-11-01

69

Low and medium energy deuteron-induced reactions on Al27  

NASA Astrophysics Data System (ADS)

The activation cross sections of (d,p), (d,2p), and (d,p?) reactions on Al27 were measured in the energy range from 4 to 20 MeV using the stacked-foils technique. Following a previous extended analysis of elastic scattering, breakup, and direct reaction of deuterons on Al27, for energies from 3 to 60 MeV, the preequilibrium and statistical emissions are considered in the same energy range. Finally, all deuteron-induced reactions on Al27 including the present data measured up to 20 MeV deuteron energy are properly described due to a simultaneous analysis of the elastic scattering and reaction data.

Bém, P.; Šime?ková, E.; Honusek, M.; Fischer, U.; Simakov, S. P.; Forrest, R. A.; Avrigeanu, M.; Obreja, A. C.; Roman, F. L.; Avrigeanu, V.

2009-04-01

70

Electron induced [ital pd] and [ital ppn] breakup of [sup 3]He with full inclusion of final-state interactions  

SciTech Connect

Exclusive electron scattering on [sup 3]He leading to the [ital pd] and [ital ppn] breakup is studied under full treatment of the final-state interaction (FSI). Realistic [ital NN] forces are used. The importance of FSI is demonstrated in several examples, among them deuteron knock-out data which are well described.

Golak, J.; Kamada, H.; Witala, H.; Gloeckle, W.; Ishikawa, S. (Institut fuer Theoretische Physik II, Ruhr-Universitaet Bochum, D44780 Bochum (Germany) Institute of Physics, Jagellonian University, PL-30059 Cracow (Poland) Department of Physics, Tohoku University, Sendai 980 (Japan))

1995-04-01

71

Configuration-space Faddeev calculation for proton-deuteron observables at energy E{sub lab} = 3 MeV  

SciTech Connect

A new computational method for solving the nucleon-deuteron breakup scattering problem has been applied to study the elastic neutron- and proton-deuteron scattering on the basis of the configuration-space Faddeev-Noyes-Noble-Merkuriev equations. This method is based on the spline-decomposition in the angular variable and on a generalization of the Numerov method for the hyperradius. The Merkuriev-Gignoux-Laverne approach has been generalized for arbitrary nucleon-nucleon potentials and with an arbitrary number of partial waves taken into account. The nucleon-deuteron observables at the incident nucleon energy 3 MeV have been calculated using the charge-independent AV14 nucleon-nucleon potential including the Coulomb force for the proton-deuteron scattering. Results have been compared with those of other authors and with experimental proton-deuteron scattering data.

Suslov, V. M.; Filikhin, I.; Vlahovic, B.; Slaus, I. [Department of Physics, North Carolina Central University, 1801 Fayetteville Street, Durham, NC 27707,USA (United States); Braun, M. A. [Department of Physics, North Carolina Central University, 1801 Fayetteville Street, Durham, NC 27707,USA (United States); Department of High Energy Physics and Elementary Particles,Saint-Petersburg State University, 198504, Petrodvorets, St. Petersburg (Russian Federation)

2011-10-24

72

Probing neutron correlations through nuclear break-up  

E-print Network

The effect of initial correlations between nucleons on the nuclear break-up mechanism is studied. A quantum transport theory which extends standard mean-field approach is developed to incorporate short range pairing correlation as well as direct nucleon-nucleon collisions. A time evolution of the nuclear break-up from a correlated system leading to the emission of two particles to the continuum is performed. We show that initial correlations have strong influence on relative angles between particles emitted in coincidence. The present qualitative study indicates that nuclear break-up might be a tool to infer the residual interaction between nucleons in the nuclear medium.

Marlene Assie; Denis Lacroix

2009-07-01

73

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

74

JET BREAK-UP IN ELECTROHYDRODYNAMIC ATOMIZATION IN THE CONE-JET MODE  

Microsoft Academic Search

The jet break-up mechanism has been investigated with a high-resolution camera . A model is presented, which is able to predict the droplet size, the velocity at jet break-u p, and the wavelength at jet break-up. A new theoretical derivation of the droplet size scaling will be given. It was found that the jet break-up mechanism depends on the ratio

R. P. A. Hartman; D. J. Brunner; D. M. A. Camelot; J. C. M. Marijnissen; B. Scarlett

2000-01-01

75

ADVANCES IN ATMOSPHERIC SCIENCES, VOL. 26, NO. 4, 2009, 701706 Variability of Northeast China River Break-up Date  

E-print Network

River Break-up Date WANG Huijun1,2 ( ¡) and SUN Jianqi1,2 (ê ) 1 Institute of Atmospheric Physics investigates the variability of the break-up dates of the rivers in Northeast China from their icebound states for the period of 1957­2005 and explores some potential explanatory mechanisms. Results show that the break-up

76

Variability of Northeast China river break-up date  

Microsoft Academic Search

This paper investigates the variability of the break-up dates of the rivers in Northeast China from their icebound states\\u000a for the period of 1957–2005 and explores some potential explanatory mechanisms. Results show that the break-up of the two\\u000a major rivers (the Heilongjiang River and Songhuajiang River) was about four days earlier, and their freeze-up was about 4–7\\u000a days delayed, during

Huijun Wang; Jianqi Sun

2009-01-01

77

Coastal landfast sea ice decay and breakup in northern Alaska: Key processes and seasonal prediction  

NASA Astrophysics Data System (ADS)

Seasonal breakup of landfast sea ice consists of movement and irreversible ice detachment in response to winds or oceanic forces in the late stages of ice decay. The breakup process of landfast sea ice in the Chukchi Sea at Barrow, Alaska, was analyzed for the years 2000 through 2010 on the basis of local observations of snow and ice conditions, weather records, image sequences obtained from cameras, coastal X band marine radar, and satellite imagery. We investigated the relation of breakup to winds, tides, and nearshore current measurements from a moored acoustic Doppler current profiler. Two breakup modes are distinguished at Barrow on the basis of the degree of ice decay. Mechanical breakup due to wind and oceanic forces follows ablation and weakening of the ice. Thermal breakup is the result of ice disintegration under melt ponds, requiring little force to induce dispersion. Grounded pressure ridges are pivotal in determining the breakup mode. The timing of thermal breakup of the nearshore ice cover was found to correlate with the measured downwelling solar radiation in June and July. This linkage allows for the development of an operational forecast of landfast ice breakup. Results from forecasts during 2 years demonstrate that thermal breakup can be predicted to within a couple of days 2 weeks in advance. The cumulative shortwave energy absorbed by the ice cover provides for a measure of the state of ice decay and potential for disintegration. Discriminating between the two modes of breakup bears the potential to greatly increase forecasting skill.

Petrich, Chris; Eicken, Hajo; Zhang, Jing; Krieger, Jeremy; Fukamachi, Yasushi; Ohshima, Kay I.

2012-02-01

78

Droplet Breakup of the Nematic Liquid Crystal MBBA  

E-print Network

Droplet breakup is a well studied phenomena in Newtonian fluids. One property of this behavior is that, independent of initial conditions, the minimum radius exhibits power law scaling with the time left to breakup tau. Because they have additional structure and shear dependent viscosity, liquid crystals pose an interesting complication to such studies. Here, we investigate the breakup of a synthetic nematic liquid crystal known as MBBA. We determine the phase of the solution by using a cross polarizer setup in situ with the liquid bridge breakup apparatus. Consistent with previous studies of scaling behavior in viscous-inertial fluid breakup, when MBBA is in the isotropic phase, the minimum radius decreases as tau^{1.03 \\pm 0.04}. In the nematic phase however, we observe very different thinning behavior. Our measurements of the thinning profile are consistent with two interpretations. In the first interpretation, the breakup is universal and consists of two different regimes. The first regime is characterized by a symmetric profile with a single minimum whose radius decreases as tau^{1.51 \\pm 0.06}. The second and final regime is characterized by two minima whose radii decrease as tau^{0.52 \\pm 0.11}. These results are in excellent agreement with previous measurements of breakup in the nematic phase of liquid crystal 8CB and 5CB. Interestingly, we find that the entire thinning behavior can also be fit with an exponential decay such that R_{min} \\sim exp((1.2\\times 10^2 Hz) tau). This dependence is more reminiscent of breakup in polymers where entropic stretching slows the thinning process. An analogous mechanism for slowing in liquid crystals could arise from the role played by topological constraints governing defect dynamics. Consistent with this interpretation, crossed polarizer images indicate that significant alignment of the liquid crystal domains occurs during breakup.

Benjamin Nachman; Itai Cohen

2012-12-24

79

Measurements of scattering observables for the $pd$ break-up reaction  

E-print Network

High-precision measurements of the scattering observables such as cross sections and analyzing powers for the proton-deuteron elastic and break-up reactions have been performed at KVI in the last two decades and elsewhere to investigate various aspects of the three-nucleon force (3NF) effects simultaneously. In 2006 an experiment was performed to study these effects in $\\vec{p}+d$ break-up reaction at 135 MeV with the detection system, Big Instrument for Nuclear polarization Analysis, BINA. BINA covers almost the entire kinematical phase space of the break-up reaction. The results are interpreted with the help of state-of-the-art Faddeev calculations and are partly presented in this contribution.

M. Eslami-Kalantari; H. R. Amir-Ahmadi; A. Biegun; I. Gašparic; L. Joulaeizadeh; N. Kalantar-Nayestanaki; St. Kistryn; A. Kozela; H. Mardanpour; J. G. Messchendorp; H. Moeini; A. Ramazani-Moghaddam-Arani; S. V. Shende; E. Stephan; R. Sworst

2010-01-10

80

Deuteron distribution in nuclear matter  

NASA Astrophysics Data System (ADS)

We analyze the properties of deuteron-like structures in infinite, correlated nuclear matter, described by a realistic hamiltonian containing the Urbana v14 two-nucleon and the Urbana TNI many-body potentials. The distribution of neutron-proton pairs, carrying the deuteron quantum numbers, is obtained as a function of the total momentum by computing the overlap between the nuclear matter in its ground state and the deuteron wave functions in correlated basis functions theory. We study the differences between the S- and D-wave components of the deuteron and those of the deuteron-like pair in the nuclear medium. The total number of deuteron type pairs is computed and compared with the predictions of Levinger's quasideuteron model. The resulting Levinger's factor in nuclear matter at equilibrium density is 11.63. We use the local density approximation to estimate the Levinger's factor for heavy nuclei, obtaining results which are consistent with the available experimental data from photoreactions.

Benhar, O.; Fabrocini, A.; Fantoni, S.; Illarionov, A. Yu.; Lykasov, G. I.

2002-05-01

81

Low and medium energy deuteron-induced reactions on {sup 27}Al  

SciTech Connect

The activation cross sections of (d,p), (d,2p), and (d,p{alpha}) reactions on {sup 27}Al were measured in the energy range from 4 to 20 MeV using the stacked-foils technique. Following a previous extended analysis of elastic scattering, breakup, and direct reaction of deuterons on {sup 27}Al, for energies from 3 to 60 MeV, the preequilibrium and statistical emissions are considered in the same energy range. Finally, all deuteron-induced reactions on {sup 27}Al including the present data measured up to 20 MeV deuteron energy are properly described due to a simultaneous analysis of the elastic scattering and reaction data.

Bem, P.; Simeckova, E.; Honusek, M.; Fischer, U.; Simakov, S. P.; Forrest, R. A.; Avrigeanu, M.; Obreja, A. C.; Roman, F. L.; Avrigeanu, V. [Euratom/IPP.CR Fusion Association, Nuclear Physics Institute, 25068 Rez (Czech Republic); Euratom/FZK Fusion Association, Forschungszentrum Karlsruhe, Hermann-von-Helmholtz-Platz, 1, 76344 Eggenstein-Leopoldshafen (Germany); Euratom/UKAEA Fusion Association, Culham Science Centre, Abingdon OX14 3DB (United Kingdom); 'Horia Hulubei' National Institute for Physics and Nuclear Engineering, P. O. Box MG-6, Bucharest-Magurele (Romania)

2009-04-15

82

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

83

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

84

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

85

Measurements of the breakup and neutron removal cross sections for {sup 16}C  

SciTech Connect

Measurements of the breakup and the neutron removal reactions of {sup 16}C have been made at 46 MeV/A and the decay cross sections measured. A correlation between the cluster breakup channels and the reaction Q value suggests that the reaction mechanism is strongly linked to quasielastic processes. No enhancement of the two-body cluster breakup cross section is seen for {sup 16}C. This result would indicate that {sup 16}C does not have a well developed cluster structure in the ground state, in agreement with recent calculations.

Ashwood, N. I.; Freer, M.; Clarke, N.M.; Curtis, N.; Soic, N.; Ziman, V.A. [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom); Angelique, J.C.; Lecouey, J.L.; Marques, F.M.; Normand, G.; Orr, N.A.; Timis, C. [Laboratoire de Physique Corpusculaire, ISMRA and Universite de Caen, IN2P3-CNRS, 14050 Caen Cedex (France); Bouchat, V.; Hanappe, F.; Kerckx, Y.; Materna, T. [Universite Libre de Bruxelles, CP 226, B-1050 Brussels(Belgium); Catford, W.N. [School of Electronics and Physical Sciences, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); Laboratoire de Physique Corpusculaire, ISMRA and Universite de Caen, IN2P3-CNRS, 14050 Caen Cedex (France); Dorvaux, O.; Stuttge, L. [Institut de Recherches Subatomique, IN2P3-CNRS/Universite Louis Pasteur, Boite Postale 28, 67037 Strasbourg Cedex (France); Labiche, M. [Department of Electronic Engineering and Physics, University of Paisley, Paisley PA1 2BE (United Kingdom)] [and others

2004-12-01

86

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

87

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

88

Universal nature and finite-range corrections in elastic atom-dimer scattering below the dimer breakup threshold  

E-print Network

We investigate universal behavior in elastic atom-dimer scattering below the dimer breakup threshold calculating the atom-dimer effective-range function $ak\\cot\\delta$. Using the He-He system as a reference, we solve the Schr\\"odinger equation for a family of potentials having different values of the two-body scattering length $a$ and we compare our results to the universal zero-range form deduced by Efimov, $ak\\cot\\delta=c_1(ka)+c_2(ka)\\cot[s_0\\ln(\\kappa_*a)+\\phi(ka)]$, for selected values of the three-body parameter $\\kappa_*$. Using the parametrization of the universal functions $c_1,c_2,\\phi$ given in the literature, a good agreement with the universal formula is obtained after introducing a particular type of finite-range corrections. Furthermore, we show that the same parametrization describes a very different system: nucleon-deuteron scattering below the deuteron breakup threshold. Our analysis confirms the universal character of the process, and relates the pole energy in the effective-range function of nucleon-deuteron scattering to the three-body parameter $\\kappa_*$.

A. Kievsky; M. Gattobigio

2013-06-07

89

High Energy Break-Up of Few-Nucleon Systems  

E-print Network

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

Misak M. Sargsian

2008-01-14

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

Antimisting fuel breakup and flammability  

NASA Technical Reports Server (NTRS)

The breakup behavior and flammability of antimisting turbine fuels subjected to aerodynamic shear are investigated. Fuels tested were Jet A containing 0.3% FM-9 polymer at various levels of degradation ranging from virgin AMK to neat Jet A. The misting behavior of the fuels was quantified by droplet size distribution measurements. A technique based on high resolution laser photography and digital image processing of photographic records for rapid determination of droplet size distribution was developed. The flammability of flowing droplet-air mixtures was quantified by direct measurements of temperature rise in a flame established in the wake of a continuous ignition source. The temperature rise measurements were correlated with droplet size measurements. The flame anchoring phenomenon associated with the breakup of a liquid fuel in the wake of bluff body was shown to be important in the context of a survivable crash scenario. A pass/fail criterion for flammability testing of antimisting fuels, based on this flame-anchoring phenomenon, was proposed. The role of various ignition sources and their intensity in ignition and post-ignition behavior of antimisting fuels was also investigated.

Parikh, P.; Fleeter, R.; Sarohia, V.

1983-01-01

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

Electron-deuteron tensor polarization and the short range behavior of the deuteron wave function  

Microsoft Academic Search

We investigate to what extent measurements of the polarization of recoil deuterons in electron-deuteron scattering would allow us to determine the short-range behavior of the deuteron wave function. We find that even if such measurements were performed out to q=10 fm-1 with an error of +\\/-10% and in some cases even within +\\/-1%, a considerable variation in the deuteron wave

L. J. Allen; H. Fiedeldey

1979-01-01

94

Exclusive Scattering from Unpolarized and Polarized Deuteron  

SciTech Connect

We present results for exclusive electron scattering from polarized and unpolarized deuteron. We employ the Gross equation to describe the deuteron ground state, and we use the SAID parametrization of the full NN scattering amplitude to describe the final state interactions (FSIs). %We include both on-shell and positive-energy off-shell contributions %in our FSI calculation. We discuss properties of various asymmetries accessible with a polarized deuteron target and/or a polarized beam.

Sabine Jeschonnek, Jay Van Orden

2011-03-01

95

Quenching of the Deuteron in Flight  

E-print Network

We investigate the Lorentz contraction of a deuteron in flight. Our starting point is the Blankenbecler-Sugar projection of the Bethe-Salpeter equation to a 3-dimensional quasi potential equation, wqhich we apply for the deuteron bound in an harmonic oscillator potential (for an analytical result) and by the Bonn NN potential for a more realistic estimate. We find substantial quenching with increasing external momenta and a significant modification of the high momentum spectrum of the deuteron.

M. Dillig; C. Rothleitner

2006-04-24

96

The naming of the deuteron  

NASA Astrophysics Data System (ADS)

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

Stuewer, Roger H.

1986-03-01

97

Deuteron photodisintegration with polarized lasers  

E-print Network

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

G. Ramachandran; S. P. Shilpashree

2011-04-07

98

Elastic breakup cross sections of well-bound nucleons  

E-print Network

The 9Be(28Mg,27Na) one-proton removal reaction with a large proton separation energy of Sp(28Mg)=16.79 MeV is studied at intermediate beam energy. Coincidences of the bound 27Na residues with protons and other light charged particles are measured. These data are analyzed to determine the percentage contributions to the proton removal cross section from the elastic and inelastic nucleon removal mechanisms. These deduced contributions are compared with the eikonal reaction model predictions and with the previously measured data for reactions involving the re- moval of more weakly-bound protons from lighter nuclei. The role of transitions of the proton between different bound single-particle configurations upon the elastic breakup cross section is also quantified in this well-bound case. The measured and calculated elastic breakup fractions are found to be in good agreement.

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

2014-12-07

99

Nonlocality in deuteron stripping reactions.  

PubMed

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

Timofeyuk, N K; Johnson, R C

2013-03-15

100

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

101

Intrusive Thoughts: A Primary Variable in Breakup Distress  

ERIC Educational Resources Information Center

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

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

2013-01-01

102

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

E-print Network

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

PHENIX Collaboration; A. Adare

2007-11-25

103

On the breakup of viscous liquid threads  

NASA Technical Reports Server (NTRS)

A one-dimensional model evolution equation is used to describe the nonlinear dynamics that can lead to the breakup of a cylindrical thread of Newtonian fluid when capillary forces drive the motion. The model is derived from the Stokes equations by use of rational asymptotic expansions and under a slender jet approximation. The equations are solved numerically and the jet radius is found to vanish after a finite time yielding breakup. The slender jet approximation is valid throughout the evolution leading to pinching. The model admits self-similar pinching solutions which yield symmetric shapes at breakup. These solutions are shown to be the ones selected by the initial boundary value problem, for general initial conditions. Further more, the terminal state of the model equation is shown to be identical to that predicted by a theory which looks for singular pinching solutions directly from the Stokes equations without invoking the slender jet approximation throughout the evolution. It is shown quantitatively, therefore, that the one-dimensional model gives a consistent terminal state with the jet shape being locally symmetric at breakup. The asymptotic expansion scheme is also extended to include unsteady and inerticial forces in the momentum equations to derive an evolution system modelling the breakup of Navier-Stokes jets. The model is employed in extensive simulations to compute breakup times for different initial conditions; satellite drop formation is also supported by the model and the dependence of satellite drop volumes on initial conditions is studied.

Papageorgiou, Demetrios T.

1995-01-01

104

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

E-print Network

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

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

2013-03-19

105

Dynamics and Time-scales in Breakup and Fusion  

NASA Astrophysics Data System (ADS)

Nuclear reaction dynamics at energies near the fusion barrier is known to be dominated by quantum effects, such as tunneling, and quantum superpositions that gives rise to channel couplings. The understanding of near-barrier reaction dynamics continues to evolve as improved experimental techniques reveal new facets of interaction dynamics. Recent coincidence measurements using weakly bound stable nuclei have not only provided a complete picture of the physical mechanisms triggering breakup, but have also shown how information on reaction dynamics occurring on time-scales of ~zepto-seconds can be obtained experimentally. These new experimental findings demand major developments in quantum models of low energy nuclear reactions.

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

2013-03-01

106

Elastic scattering of deuterons by carbon  

NASA Technical Reports Server (NTRS)

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

Varma, G. K.; Franco, V.

1977-01-01

107

Hard Break-Up of Two-Nucleons from the 3He Nucleus  

E-print Network

We investigate a large angle photodisintegration of two nucleons from the $^3$He nucleus within the framework of the hard rescattering model (HRM). In the HRM a quark of one nucleon knocked out by an incoming photon rescatters with a quark of the other nucleon leading to the production of two nucleons with large relative momentum. Assuming the dominance of the quark-interchange mechanism in a hard NN scattering, the HRM allows to express the amplitude of a two-nucleon break-up reaction through the convolution of photon-quark scattering, $NN$ hard scattering amplitude and nuclear spectral function. The photon-quark scattering amplitude can be explicitly calculated in the high energy regime, whereas for $NN$ scattering one uses the fit of the available experimental data. The HRM predicts several specific features for the hard breakup reaction. First, the cross section will approximately scale as $s^{-11}$. Secondly, the $s^{11}$ weighted cross section will have the shape of energy dependence similar to that of $s^{10}$ weighted $NN$ elastic scattering cross section. Also one predicts an enhancement of the $pp$ breakup relative to the $pn$ breakup cross section as compared to the results from low energy kinematics. Another result is the prediction of different spectator momentum dependencies of $pp$ and $pn$ breakup cross sections. This is due to the fact that same-helicity $pp$-component is strongly suppressed in the ground state wave function of $^3$He. Because of this suppression the HRM predicts significantly different asymmetries for the cross section of polarization transfer $NN$ breakup reactions for circularly polarized photons. For the $pp$ breakup this asymmetry is predicted to be zero while for the $pn$ it is close to ${2\\over 3}$.

Misak M Sargsian; Carlos Granados

2009-08-21

108

Towards High Precision Deuteron Polarimetry  

SciTech Connect

A finite electric dipole moment (EDM) in any fundamental system would constitute a signal for new physics. The deuteron presents itself as an optimal candidate both experimentally and theoretically. A new storage ring technique is being developed for which a small change in the vertical polarization would be a signal of a non-zero EDM. A novel polarimeter concept is under investigation. Besides being highly efficient, this polarimeter should continuously monitor the beam polarization, guaranteeing optimal sensitivity. Detailed studies on systematic error control, in addition to the measurement of cross sections and analyzing powers, were carried out at KVI-Groningen in The Netherlands. Measurements were conducted at COSY-Juelich in Germany yielding high efficiencies. The (statistics limited) ability to track changes in polarization at the level of a few hundred parts-per-million has been demonstrated. Further studies and developments to meet the final goal of sub-part-per-million sensitivity are in progress.

Silva e Silva, M. da [KVI, University of Groningen, Groningen (Netherlands)

2009-08-04

109

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

110

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

E-print Network

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

M. Fallot; J. A. Scarpaci; D. Lacroix; Ph. Chomaz; J. Margueron

2001-11-06

111

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

PubMed Central

A simplified three-dimensional (3-D) zero-thickness shell model was developed to recover the non-spherical response of thick-shelled encapsulated microbubbles subjected to ultrasound excitation. The model was validated by comparison with previously developed models and was then used to study the mechanism of bubble break-up during non-spherical deformations resulting from the presence of a nearby rigid boundary. The effects of the shell thickness and the bubble standoff distance from the solid wall on the bubble break-up were studied parametrically for a fixed insonification frequency and amplitude. A diagram of bubble shapes versus the normalized shell thickness and wall standoff was derived, and the potential bubble shapes at break-up from reentrant jets were categorized resulting in four distinct zones. PMID:23556560

Hsiao, Chao-Tsung; Chahine, Georges L.

2013-01-01

112

Critical role of pinning defects in scroll-wave breakup in active media  

NASA Astrophysics Data System (ADS)

The breakup of rotating scroll waves in three-dimensional excitable media has been linked to important biological processes. The known mechanisms for this transition almost exclusively involve the dynamics of the scroll filament, i.e., the line connecting the phase singularities. In this paper, we describe a novel defect-induced route to breakup of a scroll wave pinned by an inexcitable obstacle partially extending through the bulk of the medium. The wave is helically wound around the defect inducing sudden changes in velocity components of the wavefront at the obstacle boundary. This results in breakup far from the filament, eventually giving rise to spatiotemporal chaos. Our results suggest a potentially critical role of pinning obstacles in the onset of life-threatening disturbances of cardiac activity.

Sridhar, S.; Ghosh, Antina; Sinha, Sitabhra

2013-09-01

113

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

Microsoft Academic Search

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

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

2006-01-01

114

Breakup phenomena study in 7Li+208Pb reaction using 8PLP  

NASA Astrophysics Data System (ADS)

Inclusive ? particle spectra for 7Li+208Pb reaction has been studied. There are different reaction mechanism such as pickup/transfer including breakup influence the observed ? particle spectra . Presence of different bands of triton indicates the origin is different which needs more study.

Rath, P. K.; Vardaci, E.

2015-01-01

115

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

116

Age of Seychelles India break-up  

Microsoft Academic Search

Many continental flood basalt provinces are spatially and temporally linked with continental break-up. Establishing the relative timing of the two events is a key step in determining their causal relationship. Here we investigate the example of the Deccan Traps and the separation of India and the Seychelles. Whilst there has been a growing consensus as to the age of the

J. S. Collier; V. Sansom; O. Ishizuka; R. N. Taylor; T. A. Minshull; R. B. Whitmarsh

2008-01-01

117

Ice breakup on the Skunk River  

USGS Multimedia Gallery

This image and associated video captures the breakup of ice cover on the Skunk River at Augusta, Iowa, on February 17, 2011, at approximately 3:00 p.m. local time. The river stage at the time was 14.50 feet (elevation 1,179.41 feet NGVD29). A preliminary estimate of the discharge at the time of the ...

118

Role of pion exchange in ? meson photoproduction on the deuteron  

NASA Astrophysics Data System (ADS)

Incoherent ? photoproduction on the deuteron is studied, with the main emphasis on the role of final-state interactions. In addition to the previously studied mechanisms of N N and ? N rescatterings, the role of an intermediate pion exchange is considered in detail, where first a pion is photoproduced on one nucleon and then rescatters into an ? meson on the other, the spectator nucleon. It is found that the role of this pion-mediated contribution is comparable in size to that of ? N rescattering. Results for total and semi-inclusive differential cross sections and associated polarization observables are presented. In particular, polarization observables show significant sensitivity to final-state interactions.

Fix, A.; Arenhövel, H.; Levchuk, M.; Tammam, M.

2015-01-01

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

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

NASA Astrophysics Data System (ADS)

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

Christlmeier, Stefan; Grießhammer, Harald W.

2008-06-01

121

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

122

High-Energy Nucleus-Nucleus Collisions. I. General Theory and Applications to Deuteron-Deuteron Scattering  

Microsoft Academic Search

A theoretical analysis of the collisions of high-energy nuclei with nuclei is carried out by means of a simple extension of the Glauber approximation. Effects of multiple collisions are taken into account. The general formalism is applied to deuteron-deuteron collisions. Expressions are derived for single-, double-, triple-, and quadruple-scattering amplitude operators for deuteron-deuteron collisions in terms of nucleon-nucleon scattering amplitude

Victor Franco

1968-01-01

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

Nuclear break-up of 11Be  

E-print Network

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

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

2007-09-25

125

Coupled map lattice model of jet breakup  

SciTech Connect

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

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

2001-01-25

126

Rift Geometry and Evolution Associated with the Break-up of Pangea  

Microsoft Academic Search

Diabase dikes related to the rifting of Pangea have been used to elucidate mechanisms by which the super-continent broke-up since the early 1970s. Subsequently, these dikes were related to each other and the massive sills and lava flows that make up the Central Atlantic Magmatic Province (CAMP). Our research focuses on the dikes and mechanisms of continental break-up in the

C. Debnam; E. K. Beutel

2004-01-01

127

A mesonic analog of the deuteron  

NASA Astrophysics Data System (ADS)

Using the LAMP model for nuclear quark structure, we calculate the binding energy and quark structure of a B meson merging with a D meson. Our variational calculation shows that a molecular, deuteron-like state structure changes rather abruptly, as the separation between the two mesons decreases, and at a separation of about 0.14 fm, the hadronic system transforms into a four-quark bound state, although one maintaining an internal structure rather than that of a four-quark "bag." Unlike the deuteron, pion exchange does not provide any contribution to the ? 150 MeV binding.

Silbar, Richard R.; Goldman, T.

2014-12-01

128

Intense deuteron beam investigation by activation yield-ratio technique  

NASA Astrophysics Data System (ADS)

In this work, the intense deuteron beam from a plasma focus device is investigated by the activation yield-ratio technique. It is shown that boron-carbide (B 4C) and boron-nitride (BN) are complimentary targets for high energy deuteron beam studies. For deuteron spectra of the form dN/dE?E, when deuteron spectra decrease relatively gradually ( n<6) BN is a better choice, while for the case of very rapidly decreasing deuteron spectra ( n>6), B 4C is more suitable.

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

2009-10-01

129

Accelerated deuterons in cluster-fusion experiments  

SciTech Connect

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

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

1991-12-01

130

Deuteron forward photodisintegration: Meson currents and relativity  

Microsoft Academic Search

The few nucleon problem in nuclear physics and the few electron problem in atomic physics are shown to possess similarities. Relativistic aspects of the latter are reviewed. The radiative decay of the (3) P1 excited state of helium-like ions to the (1)So ground state is shown to be a theoretical analoque of low energy deuteron forward photodisintegration. Both have large

J. L. Friar

1983-01-01

131

Dealing With Romantic Break-Up and Rejection: Understanding the Nature of Relationships and Romantic Break-Up  

Microsoft Academic Search

The study sought to better understand the psychological variables affecting romantic break-up and romantic rejection. Individuals who reported higher self-esteem, less rejection sensitivity, and lower levels of attachment anxiety reported less adverse effects to break-up. Contrary to predictions, who initiated the break-up did not result in significant differences in adverse symptoms. Moreover, no gender differences were found for response to

Boyan Robak; Paul Griffin

2012-01-01

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

Polar lake circulation during ice break-up  

NASA Astrophysics Data System (ADS)

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

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

2014-05-01

135

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

136

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

137

Breakup of double emulsions in constrictions Haosheng Chen,ab  

E-print Network

Breakup of double emulsions in constrictions Haosheng Chen,ab Jiang Li,cd Ho Cheung Shum,a Howard A We report the controlled breakup of double emulsion droplets as they flow through an orifice. Double emulsions, which were originally referred to as emulsion liquid membranes, were conceived

138

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

139

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

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

2011-01-01

141

Numerical simulation of turbulent jet primary breakup in Diesel engines  

E-print Network

Numerical simulation of turbulent jet primary breakup in Diesel engines Peng Zeng1 Marcus Herrmann and Aerospace Engineering Arizona State University "Micro-Macro Modelling and Simulation of Liquid-Vapour Flows" IRMA Strasbourg, 23.Jan.2008 #12;Introduction DNS of Primary Breakup in Diesel Injection Phase

Helluy, Philippe

142

Long term orbital debris environment sensitivity to spacecraft breakup parameters  

Microsoft Academic Search

The long term prediction of the orbital debris environment depends fundamentally on the dynamics of spacecraft breakups. These processes provide the numbers, initial velocities, positions, and ballistic coefficients for newly formed debris fragments. Efforts are ongoing to model satellite breakup phenomenon using a variety of models with varying degrees of complexity. This paper provides a comparison of four of the

Al Reinhardt; William Borer; Kenneth Yates

1993-01-01

143

Photoproduction and Photodisintigration Processes of the Deuteron  

NASA Astrophysics Data System (ADS)

In 2002 the (SLAC) Crystal Ball multiphoton spectrometer was moved from Brookhaven National Laboratory to Mainz to take advantage of the excellent facilities at MAMI. The combination of TAPS and the Crystal Ball forms a truly 4? detection system for protons and neutrons. A photon beam with energies between 400 and 855 MeV has been used with a liquid deuterium target to investigate several photoproduction and photodisintigration processes. Among these are coherent ?^0 production on the deuteron, ?^0 production off the individual quasi-free nucleons, and the photodisintigration of the deuteron into a proton and a neutron. While each of these processes has physics interest, the latter can also be used to calibrate the detection efficiency of the Crystal Ball and TAPS for neutrons. We will report on the preliminary physics and the calibration results from the first measurements made with the deuterium target.

Briscoe, William; Downie, Evie

2005-04-01

144

Exclusive nuclear reactions: Can you count on the deuteron  

SciTech Connect

Three of the simplest nuclear reactions -- (1) electron-deuteron elastic scattering, (2) electro-disintegration of the deuteron near threshold and at high momentum transfer, and (3) photodisintegration of the deuteron at high energy -- were believed to have unique signatures for OCD effects in nuclei. The progress in the past few years with regard to these reactions will be traced and the results will be compared with recent theoretical predictions. 36 refs., 12 figs., 1 tab.

Holt, R.J.

1991-01-01

145

The Photoelectric Effect of the Deuteron  

Microsoft Academic Search

Theoretical cross sections for the dissociation of the deuteron by absorption of gamma-rays, the Chadwick-Goldhaber effect, have been calculated, by using a square well law of potential, both of the ordinary type and of the Majorana type. The curves of cross section as a function of energy for various assumed widths are given. For widths less than 2 × 10-13

G. Breit; E. U. Condon

1936-01-01

146

Proton and deuteron radiative capture to A = 13 nuclei  

NASA Astrophysics Data System (ADS)

Differential capture 12C(p, ?) 13N and 11B(d, ?) 13C cross sections have been measured in the excitation energy region between 20 and 45 MeV in 13N and 25 and 42 MeV in 13C. Angular distributions are given for the p? channel at each energy, while the d? excitation function has been measured at 60°. The p? 0 data show, besides a direct capture term, the excitation of giant dipole resonances based on excited states of the compound nucleus. The main feature of the deuteron capture cross section can be understood in terms of a mechanism in which the proton-neutron pair is captured in the same single particle configuration by the 11B core.

Corvisiero, P.; Anghinolfi, M.; Ricco, G.; Sanzone, M.; Taiuti, M.; Zucchiatti, A.

1991-04-01

147

Proton-Deuteron Elastic Scattering at Very Low Energy.  

NASA Astrophysics Data System (ADS)

Contemporary nuclear theory is unable to furnish an adequate quantitative description of the three-nucleon system. The non-relativistic, nucleons-only dynamical theory--whether utilizing dispersion-theoretic, meson field -theoretic, or phenomenologically derived nuclear potentials --fails to replicate the trinucleon binding energies without the inclusion of three-body forces characterized by ad hoc parameters. Attempts to replicate three-nucleon continuum observables below the deuteron breakup threshold have been fairly successful in the case of the n-d system, but significant failures have attended these attempts for the p-d scattering system. The most serious such failure is a discrepancy between the theoretical and phenomenological values of the p-d S-wave scattering lengths. Besides suggesting the existence of subtle interactions between the nuclear and electrostatic forces in the three-body system, this discrepancy has challenged a long-held, though as yet incompletely understood, assumption that approximately linear correlations exist between the trinucleon binding energy and various parameters characterizing the three-nucleon system. A consensus has emerged among theorists that these discrepancies are the result of a singularity in the doublet S-wave effective range function near the two-body threshold that hinders the ability to infer the scattering length on the basis of measurements made at excessively high scattering energies. Since the doublet and quartet S-wave eigenphaseshifts are coupled in the cross section, errors in inferring the former are reflected in erroneous determinations of the latter. Relative differential cross sections for the ^2H(p,p)^2H reaction have been measured at a number of (center-of-mass) angles between 36.9^circ and 140.5 ^circ at a proton laboratory energy of 315 keV. These data are part of a larger set that also includes measurements of the relative cross section at 240 keV. The data are compared with theoretical calculations of the cross sections that explore the influence of various partial wave eigenphaseshifts and spin mixing parameters, preparatory to a global phase shift analysis being undertaken by the author and his collaborators.

Black, Timothy Charles

1995-11-01

148

The Nd Break-Up Process in Leading Order in a Three-Dimensional Approach  

E-print Network

A three-dimensional approach based on momentum vectors as variables for solving the three nucleon Faddeev equation in first order is presented. The nucleon-deuteron break-up amplitude is evaluated in leading order in the NN T-matrix, which is also generated directly in three dimensions avoiding a summation of partial wave contributions. A comparison of semi-exclusive observables in the $d(p,n)pp$ reaction calculated in this scheme with those generated by a traditional partial wave expansion shows perfect agreement at lower energies. At about 200 MeV nucleon laboratory energies deviations in the peak of the cross section appear, which may indicate that special care is required in a partial wave approach for energies at and higher than 200 MeV. The role of higher order rescattering processes beyond the leading order in the NN T-matrix is investigated with the result, that at 200 MeV rescattering still provides important contributions to the cross section and certain spin observables. The influence of a relativistic treatment of the kinematics is investigated. It is found that relativistic effects become important at projectile energies higher than 200 MeV.

I. Fachuddin; Ch. Elster; W. Gloeckle

2003-07-02

149

Thermonuclear breakup reactions of light nuclei. I - Processes and effects. [in astrophysic plasmas  

NASA Technical Reports Server (NTRS)

Temperature and density conditions are considered for the occurrence of breakup reactions of light nuclei in astrophysical plasmas. The proton-induced endothermic process is shown to be the principal mechanism for nuclear breakdown in a plasma. The phenomenon occurs at a temperature of about 1 MeV, which is a fraction of the typical binding energy per nucleon in nuclei. The temperature for breakup of He-4 is about twice as large, because of the higher binding energy. Depending on the temperature attained in the plasma, the initial concentration of elements heavier than hydrogen can be depleted. However, if it attains a temperature of about 1 MeV, breaking up the metals (C, N, O, Ne, Mg) but not He-4, an increase in the He-4 abundance by as much as 10 percent can result, since these elements essentially break down to alpha particles.

Guessoum, Nidhal; Gould, Robert J.

1989-01-01

150

Impacts, tillites, and the breakup of Gondwanaland  

NASA Technical Reports Server (NTRS)

Mathematical analysis demonstrates that substantial impact crater deposits should have been produced during the last 2 Gy of Earth's history. Textures of impact deposits are shown to resemble textures of tillites and diamictites of Precambrian and younger ages. The calculated thickness distribution for impact crater deposits produced during 2 Gy is similar to that of tillites and diamictites of 2 Ga or younger. We suggest, therefore, that some tillites/diamictites could be of impact origin. Extensive tillite/diamictite deposits predated continental flood basalts on the interior of Gondwanaland. Significantly, other investigators have already associated impact cratering with flood basalt volcanism and continental rifting. Thus, it is proposed that the breakup of Gondwanaland could have been initiated by crustal fracturing from impacts.

Oberbeck, Verne R.; Marshall, John R.; Aggarwal, Hans

1993-01-01

151

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

SciTech Connect

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

Christlmeier, Stefan [Institut fuer Theoretische Physik (T39), Physik-Department, Technische Universitaet Muenchen, D-85747 Garching (Germany); Griesshammer, Harald W. [Institut fuer Theoretische Physik (T39), Physik-Department, Technische Universitaet Muenchen, D-85747 Garching (Germany); Center for Nuclear Studies, Department of Physics, The George Washington University, Washington DC 20052 (United States)

2008-06-15

152

Study on the cylindrical liquid nanojet break-up phenomenon  

NASA Astrophysics Data System (ADS)

In this paper the liquid argon nanojet break-up phenomenon was studied using the molecular dynamics method. The effects of temperature, nozzle diameter and body force on the nanojet break-up length and time were simulated. Meanwhile, the particle size, wave length and the frequency of the disturbance were compared with the results of linear stability analysis. The results showed that even though the fluid becomes discontinuous, the traditional linear stability analysis can be used to make a rough calculation of the nanojet break-up.

Zhao, Jianbo

2015-04-01

153

.Chekanov:(anti)deuteronproductionatHERA Deuteron and antideuteron production inDeuteron and antideuteron production in  

E-print Network

during "freeze-out" stage of fireball via coalescence: - if B2 is the same for particles multiquark particle with one proton and one neutron p + n d due to overlap of wave functions in the final to be understood (anti)Deuterons in elementary particle collisions Pp n #12;.Chekanov

154

Adult Attachment and the Break-Up of Romantic Relationships  

Microsoft Academic Search

The study of the break-up of romantic relationships was integrated into research on adults' attachment representations. Eighty-three female subjects, currently married mothers of one child, were given the Adult Attachment Interview (AAI; George, Kaplan, & Main, 1985), supplemented with questions about the break-up of relationships with former husbands or boyfriends. Subjects who were classified as Unresolved with respect to loss

Marian J. Bakermans-Kranenburg; Marinus H. van IJzendoora

1997-01-01

155

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

156

Breakup and coalescence characteristics of a hollow cone swirling spray  

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

157

Measurement of the Tensor Structure Function b1 of the Deuteron  

NASA Astrophysics Data System (ADS)

The Hermes experiment has investigated the tensor spin structure of the deuteron using the 27.6GeV/c positron beam of DESY HERA. The use of a tensor-polarized deuteron gas target with only a negligible residual vector polarization enabled the first measurement of the tensor asymmetry Azzd and the tensor structure function b1d for average values of the Bjorken variable 0.01mechanism that leads to nuclear shadowing in unpolarized scattering.

Airapetian, A.; Akopov, N.; Akopov, Z.; Amarian, M.; Ammosov, V. V.; Andrus, A.; Aschenauer, E. C.; Augustyniak, W.; Avakian, R.; Avetissian, A.; Avetissian, E.; Bailey, P.; Balin, D.; Baturin, V.; Beckmann, M.; Belostotski, S.; Bernreuther, S.; Bianchi, N.; Blok, H. P.; Böttcher, H.; Borissov, A.; Borysenko, A.; Bouwhuis, M.; Brack, J.; Brüll, A.; Bryzgalov, V.; Capitani, G. P.; Chen, T.; Chiang, H. C.; Ciullo, G.; Contalbrigo, M.; Dalpiaz, P. F.; Leo, R. De; Demey, M.; Nardo, L. De; Sanctis, E. De; Devitsin, E.; Nezza, P. Di; Dreschler, J.; Düren, M.; Ehrenfried, M.; Elalaoui-Moulay, A.; Elbakian, G.; Ellinghaus, F.; Elschenbroich, U.; Fabbri, R.; Fantoni, A.; Fechtchenko, A.; Felawka, L.; Fox, B.; Frullani, S.; Gapienko, G.; Gapienko, V.; Garibaldi, F.; Garrow, K.; Garutti, E.; Gaskell, D.; Gavrilov, G.; Gharibyan, V.; Graw, G.; Grebeniouk, O.; Greeniaus, L. G.; Gregor, I. M.; Hafidi, K.; Hartig, M.; Hasch, D.; Heesbeen, D.; Henoch, M.; Hertenberger, R.; Hesselink, W. H. A.; Hillenbrand, A.; Hoek, M.; Holler, Y.; Hommez, B.; Iarygin, G.; Ivanilov, A.; Izotov, A.; Jackson, H. E.; Jgoun, A.; Kaiser, R.; Kinney, E.; Kisselev, A.; Kopytin, M.; Korotkov, V.; Kozlov, V.; Krauss, B.; Krivokhijine, V. G.; Lagamba, L.; Lapikás, L.; Laziev, A.; Lenisa, P.; Liebing, P.; Linden-Levy, L. A.; Lipka, K.; Lorenzon, W.; Lu, H.; Lu, J.; Lu, S.; Ma, B.-Q.; Maiheu, B.; Makins, N. C. R.; Mao, Y.; Marianski, B.; Marukyan, H.; Masoli, F.; Mexner, V.; Meyners, N.; Mikloukho, O.; Miller, C. A.; Miyachi, Y.; Muccifora, V.; Nagaitsev, A.; Nappi, E.; Naryshkin, Y.; Nass, A.; Negodaev, M.; Nowak, W.-D.; Oganessyan, K.; Ohsuga, H.; Pickert, N.; Potashov, S.; Potterveld, D. H.; Raithel, M.; Reggiani, D.; Reimer, P. E.; Reischl, A.; Reolon, A. R.; Riedl, C.; Rith, K.; Rosner, G.; Rostomyan, A.; Rubacek, L.; Rubin, J.; Ryckbosch, D.; Salomatin, Y.; Sanjiev, I.; Savin, I.; Schäfer, A.; Schill, C.; Schnell, G.; Schüler, K. P.; Seele, J.; Seidl, R.; Seitz, B.; Shanidze, R.; Shearer, C.; Shibata, T.-A.; Shutov, V.; Simani, M. C.; Sinram, K.; Stancari, M.; Statera, M.; Steffens, E.; Steijger, J. J. M.; Stenzel, H.; Stewart, J.; Stinzing, F.; Stösslein, U.; Tait, P.; Tanaka, H.; Taroian, S.; Tchuiko, B.; Terkulov, A.; Tkabladze, A.; Trzcinski, A.; Tytgat, M.; Vandenbroucke, A.; van der Nat, P. B.; van der Steenhoven, G.; Vetterli, M. C.; Vikhrov, V.; Vincter, M. G.; Vogel, C.; Vogt, M.; Volmer, J.; Weiskopf, C.; Wendland, J.; Wilbert, J.; Ye, Y.; Ye, Z.; Yen, S.; Zihlmann, B.; Zupranski, P.

2005-12-01

158

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

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

159

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

PubMed

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

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

2010-02-01

160

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

161

Photoproduction and Photodisintigration Processes of the Deuteron  

NASA Astrophysics Data System (ADS)

The Mainz Mictrotron (MAMI) is a continuous wave electron accelerator located at the Institut fuer Kernphysik in Mainz, Germany. It is the best tagged photon facility below 855 MeV and has extremely high energy resolution. TAPS, or Two Arm Photon Spectrometer, is a high resolution photon detection system that has been used at MAMI for the past fifteen years. In 2002 the (SLAC) Crystal Ball multiphoton spectrometer was moved from Brookhaven National Laboratory to Mainz due to the excellent facilities at MAMI. The combination of TAPS and the Crystal Ball form a truly 4p detection system for protons and neutrons. A photon beam with energies between 400 and 855 MeV has been used with a liquid deuterium target to investigate several photoproduction and photodisintigration processes. Among these are coherent p0 production on the deuteron itself, p0 production off the individual quasi-free nucleons, and the photodisintigration of the deuteron into a proton and a neutron. While each of these processes have physics interest, the latter can also be used to calibrate the detection efficiency of the Crystal Ball and TAPS for neutrons. We plan to report on the preliminary physics and calibration results from the first measurements made with the deuterium target.

Gohs, Jessica; Briscoe, William; Hornidge, Dave; Moores, Korwin; McDermit, Kevin; Bulmer, Kris; Patterson, Steven; Starotsin, Sasha; Rost, Mattias; Downie, Eve

2004-10-01

162

On the Eddy Break-Up coefficient  

SciTech Connect

Advanced combustion models for turbulent reactive flow are still not at a stage where they are useful for engineering calculations of practical systems such as gas turbine combustors. State-of-the-art methods still use the Eddy Break-Up (EBU) model to give the fast chemistry limit to the reaction rate with a global kinetics formula being used to estimate the kinetically limited rates. While there must continue to be basic reservations about the general correctness of the EBU approach, it has recently been shown that the EBU limit does have a basis in theory for the nonpremixed case. The theoretical result of Bilger for the mixing-limited reaction rate shows that it is proportional to the probability density of the mixture being at stoichiometric. The EBU model, however, takes it as being proportional to the mass fraction of the deficient reactant, but this is in turn a property of the mixture fraction pdf (probability density function) under fast chemistry conditions. The theoretical result can be used to evaluate the correct value of the EBU coefficient, which is usually taken as a constant but with quite widely varying values. In this paper the authors evaluate this theoretical value for the EBU coefficient using two commonly adopted forms of the pdf. Recommendations are made with regard to the best values to use in practice.

Brizuela, E.A. [DSTO Aeronautical and Maritime Research Lab., Fishermens Bend, Victoria (Australia)] [DSTO Aeronautical and Maritime Research Lab., Fishermens Bend, Victoria (Australia); Bilger, R.W. [Univ. of Sydney, New South Wales (Australia). Dept. of Mechanical and Mechatronic Engineering] [Univ. of Sydney, New South Wales (Australia). Dept. of Mechanical and Mechatronic Engineering

1996-01-01

163

Indirect Determination of the GDH Integrand on the Deuteron near Photodisintegration Threshold  

NASA Astrophysics Data System (ADS)

Data obtained from measurements recently performed at the High Intensity ?-ray Source (HI?S) are being analyzed to extract the Gerasimov-Drell-Hearn (GDH) integrand on the deuteron at ?-ray energies of 3.5, 4.0, 6.0, and 10.0 MeV. Linearly polarized ?-rays were used to extract the shape of the polarized differential cross section for the d(?,n)p reaction near breakup threshold using the 88 neutron detectors of the BLOWFISH array. The coefficients of a Legendre polynomial expansion of the data were extracted and written in terms of the amplitudes and phases of the transition matrix elements. A grid search was performed to determine the amplitudes of the T-matrix elements, using the phase shifts obtained from n-p scattering data to fix the relative phases. The amplitudes are used in a low-energy expansion of the GDH integrand to determine the integrand values at each energy. This talk will provide a brief overview of the experiment, describe how the amplitudes were extracted, and compare the results obtained for the GDH integrand to theory. B. Sawatzky, Ph.D. thesis, Univ. of Virginia, 2005. SAID Analysis, http://gwdac.phys.gwu.edu/. H. Arenh"ovel et al. Nucl. Phys., A631(1998) 612c.

Blackston, M. A.; Ahmed, M. A.; Norum, B. E.; Sawatzky, B.; Weller, H. R.

2006-04-01

164

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

E-print Network

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

Kazuki Yoshida; Tokuro Fukui; Kosho Minomo; Kazuyuki Ogata

2014-07-25

165

${}^3$H production via neutron-neutron-deuteron recombination  

E-print Network

We study the recombination of two neutrons and deuteron into neutron and ${}^3$H 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 ${}^3$H via the neutron-neutron-deuteron recombination is much slower as compared to the radiative neutron-deuteron capture. We also calculate neutron-${}^3$H elastic and total cross sections.

A. Deltuva; A. C. Fonseca

2013-01-09

166

Relativistic deuteron structure function at large Q^2  

E-print Network

The deuteron deep inelastic unpolarized structure function F_2^D is calculated using the Wilson operator product expansion method. The long distance behaviour, related to the deuteron bound state properties, is evaluated using the Bethe-Salpeter equation with one particle on mass shell. The calculation of the ratio F_2^D/F_2^N is compared with other convolution models showing important deviations in the region of large x. The implications in the evaluation of the neutron structure function from combined data on deuterons and protons are discussed.

J. Paulo Pinto; A. Amorim; F. D. Santos

1997-11-21

167

The nn quasi-free nd breakup cross section: discrepancies to theory and implications on the 1S0 nn force  

E-print Network

Large discrepancies between quasi-free neutron-neutron (nn) cross section data from neutron-deuteron (nd) breakup and theoretical predictions based on standard nucleon-nucleon (NN) and three-nucleon (3N) forces are pointed out. The nn 1S0 interaction is shown to be dominant in that configuration and has to be increase to bring theory and data into agreement. Using the next-to-leading order (NLO) 1S0 interaction of chiral perturbation theory (chiPT) we demonstrate that the nn QFS cross section only slightly depends on changes of the nn scattering length but is very sensitive to variations of the effective range parameter. In order to account for the reported discrepancies one must decrease the nn effective range parameter by about 12 % from its value implied by 19charge symmetry and charge independence of nuclear forces.

H. Witala; W. Gloeckle

2010-11-22

168

Deuteron Acceleration and Fusion Neutron Production in Z-pinch plasmas  

SciTech Connect

Fusion neutron measurements were carried out on the S-300 generator (Kurchatov Institute, Moscow). We tried deuterated fibers, various types of wire arrays imploding onto a deuterated fiber, and deuterium gas puffs as Z-pinch loads. On the current level of 2 MA, the peak neutron yield of 10{sup 10} was achieved with a deuterium gas-puff. The neutron and deuteron energy spectra were quite similar in various types of Z-pinch configurations. The broad width of radial neutron spectra implied a high radial component of deuteron velocity. On the basis of neutron measurements, we concluded that neutron production mechanism is connected with the study of plasma voltage. It means that the acceleration of fast deuterons is not a secondary process but it reflects the global dynamics of Z-pinch plasmas. For this reason it is useful to add deuterium as a 'tracer' in Z-pinch loads more often. For instance, it seems attractive to prepare wire-arrays from deuterated metal wires such as Pd.

Klir, D.; Kravarik, J.; Kubes, P.; Rezac, K. [Czech Technical University, Faculty of Electrical Engineering, Department of Physics, Technicka 2, 166 27 Prague 6 (Czech Republic); Ananeev, S. S.; Bakshaev, Yu. L.; Blinov, P. I.; Chernenko, A. S.; Kazakov, E. D.; Korolev, V. D.; Ustroev, G. I. [Russian Research Center Kurchatov Institute, 1 Kurchatov Sq., 123182 Moscow (Russian Federation)

2009-01-21

169

Current reduction in a pseudo-breakup event: THEMIS observations  

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

170

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

SciTech Connect

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

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

2006-04-15

171

Deuterons and flow: At intermediate AGS energies  

SciTech Connect

A quantitative model, based on hadronic physics and Monte Carlo cascading is applied to heavy ion collisions at BNL-AGS and BEVALAC energies. The model was found to be in excellent agreement with particle spectra where data previously existed, for Si beams, and was able to successfully predict the spectra where data was initially absent, for Au beams. For Si + Au collisions baryon densities of three or four times the normal nuclear matter density ({rho}{sub 0}) are seen in the theory, while for Au + Au collisions, matter at densities up to 10 {rho}{sub 0} is anticipated. The possibility that unusual states of matter may be created in the Au beams and potential signatures for its observation, in particular deuterons and collective flow, are considered.

Kahana, D.E. [State Univ. of New York, Stony Brook, NY (United States); Pang, Y. [Brookhaven National Lab., Upton, NY (United States)]|[Columbia Univ., New York, NY (United States); Kahana, S.H. [Brookhaven National Lab., Upton, NY (United States)

1996-06-01

172

Novel Physics with Tensor Polarized Deuteron Targets  

SciTech Connect

Development of solid spin-1 polarized targets will open the study of tensor structure functions to precise measurement, and holds the promise to enable a new generation of polarized scattering experiments. In this talk we will discuss a measurement of the leading twist tensor structure function b1, along with prospects for future experiments with a solid tensor polarized target. The recently approved JLab experiment E12-13-011 will measure the lead- ing twist tensor structure function b1, which provides a unique tool to study partonic effects, while also being sensitive to coherent nuclear properties in the simplest nuclear system. At low x, shadowing effects are expected to dominate b1, while at larger values, b1 provides a clean probe of exotic QCD effects, such as hidden color due to 6-quark configuration. Since the deuteron wave function is relatively well known, any non-standard effects are expected to be readily observable. All available models predict a small or vanishing value of b1 at moderate x. However, the first pioneer measurement of b1 at HERMES revealed a crossover to an anomalously large negative value in the region 0.2 < x < 0.5, albeit with relatively large experimental uncertainty. E12-13-011 will perform an inclusive measurement of the deuteron tensor asymmetry in the region 0.16 < x < 0.49, for 0.8 < Q2 < 5.0 GeV2. The UVa solid polarized ND3 target will be used, along with the Hall C spectrometers, and an unpolarized 115 nA beam. This measurement will provide access to the tensor quark polarization, and allow a test of the Close-Kumano sum rule, which vanishes in the absence of tensor polarization in the quark sea. Until now, tensor structure has been largely unexplored, so the study of these quantities holds the potential of initiating a new field of spin physics at Jefferson Lab.

Slifer, Karl J. [UNH; Long, Elena A. [UNH

2013-09-01

173

Surface-integral formalism of deuteron stripping  

NASA Astrophysics Data System (ADS)

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

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

2014-09-01

174

Surface-integral formalism of deuteron stripping  

E-print Network

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

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

2014-08-24

175

Deuteron production and elliptic flow in relativistic heavy ion collisions  

E-print Network

in the hadronic matter. This new hadronic transport model is used to study the transverse momentum spectrum and elliptic flow of deuterons in relativistic heavy ion collisions, with the initial hadron distributions after hadronization of the produced quark...

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

2009-01-01

176

Deuteron-nucleus collisions in a multiphase transport model  

E-print Network

Using a multiphase transport model, we study pseudorapidity distributions and transverse momentum spectra in deuteron-gold collisions at RHIC. We find that final-state partonic and hadronic interactions affect the transverse momentum spectrum...

Lin, ZW; Ko, Che Ming.

2003-01-01

177

Bethe-Salpeter amplitudes and static properties of the deuteron  

SciTech Connect

Extended calculations of the deuteron{close_quote}s static properties, based on the numerical solution of the Bethe-Salpeter equation, are presented. A formalism is developed, which provides a comparative analysis of the covariant amplitudes in various representations and nonrelativistic wave functions. The magnetic and quadrupole moments of the deuteron are calculated in the Bethe-Salpeter formalism and the role of relativistic corrections is discussed. {copyright} {ital 1996 The American Physical Society.}

Kaptari, L.P.; Umnikov, A.Y.; Bondarenko, S.G.; Kazakov, K.Y.; Khanna, F.C.; Kaempfer, B. [Research Center Rossendorf, Institute for Nuclear and Hadron Physics, PF 510119, 01314 Dresden (Germany)] [Research Center Rossendorf, Institute for Nuclear and Hadron Physics, PF 510119, 01314 Dresden (Germany); [Bogoliubov Laboratory of Theoretical Physics, JINR, 141980 Dubna, Moscow Region (Russia); [INFN Section Perugia, via A. Pascoli, I-06100 Perugia (Italy); [Far Eastern State University, Vladivostok, 690000 (Russia); [University of Alberta, Edmonton, Alberta T6G 2J1 (Canada); [TRIUMF, 4004 Wesbrook Mall, Vancouver, British Columbia, Canada, V6T 2A3 (CANADA); [Institute for Theoretical Physics, Technical University, 01062 Dresden (Germany)

1996-09-01

178

The Breakup Reactions of 90MEV BERYLLIUM-9.  

NASA Astrophysics Data System (ADS)

Available from UMI in association with The British Library. Requires signed TDF. The breakup of 90MeV ^9Be has been studied for the reactions ^9Be+ ^{12}C and ^9 Be+^{120}Sn. Kinematically complete alpha + alpha + n triple coincidence data have been obtained for both of these reactions. To enable the collection of data at high statistical quality, a new type of ^8Be-detector has been developed which has a very large effective solid angle. The sequential breakup process ^ {12}C,^{120} Sn(^9Be,^9 Be*_{2.43} to ^5He_ {rm gs} + alpha to alpha + alpha + n) has been identified. Strong evidence for the direct breakup of ^9Be in the ^{120}Sn( ^9Be,^8Be _{rm gs} + n)^ {120}Sn_{rm gs} reaction has also been obtained. A Coulomb excitation calculation for this reaction is presented.

MacDonald, Euan Walter

179

Break-up stage restoration in multifragmentation reactions  

E-print Network

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

Ad. R. Raduta; E. Bonnet; B. Borderie; N. Le Neindre; S. Piantelli; M. F. Rivet

2007-02-05

180

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

SciTech Connect

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

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

2004-05-17

181

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

182

Transfer and breakup of light weakly-bound nuclei  

SciTech Connect

We investigate the origin of the effects observed in the fusion cross section of light weakly bound nuclei, through a review of the most recent experimental and theoretical works. In particular we focus on the well-documented fusion suppression at energies just above the potential barrier. We show that, besides the couplings to the breakup process, effects due to the couplings to transfer need be taken into account. The magnitude of the cross section for the direct process, breakup or transfer, is not a reliable indicator of the size of the effects induced on the elastic scattering and fusion.

Raabe, R. [GANIL, Bd Henri Becquerel, BP 55027, 14076 CAEN Cedex 05 (France)

2009-03-04

183

Precambrian Research 110 (2001) 18 Assembly and break-up of Rodinia: introduction to the  

E-print Network

Precambrian Research 110 (2001) 1­8 Editorial Assembly and break-up of Rodinia: introduction of the Rodinia supercontinent concept is described in detail by Dalziel (1997), and the assembly and break-up assembly and subsequent break-up, and Cadomian­ Baikalian­Pan African events in Eurasia and Gondwanaland

Meert, Joseph

2001-01-01

184

RESEARCH PAPER Particle Aerosolisation and Break-up in Dry Powder  

E-print Network

RESEARCH PAPER Particle Aerosolisation and Break-up in Dry Powder Inhalers 1: Evaluation to investigate the influence of turbulence on the break-up and aerosol performance of a model inhalation indicated a critical impact velocity was required to initiate agglomerate break-up (0.4 m.s-1 ). Conclusion

Frey, Pascal

185

Constituent Particle Break-up during Hot Rolling of AA 5182 Nicolas Moulin(1)  

E-print Network

Constituent Particle Break-up during Hot Rolling of AA 5182 Nicolas Moulin(1) , Estelle Parra for the final sheet forming and stamping operations. In the present work intermetallic particle break-up during tomography observations. The relation between particle break-up and particle morphology was then analysed

Paris-Sud XI, Université de

186

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

E-print Network

Modeling suggests that oblique extension facilitates rifting and continental break-up Sascha Brune; accepted 5 June 2012; published 2 August 2012. [1] 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

Kaus, Boris

187

GENTLE IONISATION AND VIOLENT BREAK-UP OF MOLECULES USING SOFT X-RAYS  

E-print Network

GENTLE IONISATION AND VIOLENT BREAK-UP OF MOLECULES USING SOFT X-RAYS Bhas Bapat PRL, Ahmedabad RRCAT Indore, June 2012 BHAS BAPAT (PRL, AHMEDABAD) BREAK-UP OF MOLECULES USING SOFT X-RAYS RRCAT INDORE INVESTIGATED RECENT RESULTS BHAS BAPAT (PRL, AHMEDABAD) BREAK-UP OF MOLECULES USING SOFT X-RAYS RRCAT INDORE

Bapat, Bhas

188

Propagation of continental break-up in the southwestern South China Sea  

E-print Network

Propagation of continental break-up in the southwestern South China Sea R HUCHONt'2, T. N. H on the southwestern tip of the South China Sea oceanic basin, where propagation of continental break-up occurred of break-up propagation. Thus, strain localization occurs at the tip of the propagating oceanic crust just

Nicolas, Chamot-Rooke

189

Late Cretaceous IndiaMadagascar fit and timing of break-up related magmatism  

E-print Network

Late Cretaceous India±Madagascar fit and timing of break-up related magmatism T. H. Torsvik1 *, R et al., 1995; Torsvik et al., 1998). During this Late Cretaceous break-up event, the western margin reconstruction, south-west India runs roughly subparallel with the first known break-up related magnetic anomaly

Torsvik, Trond Helge

190

A Model for the Breakup of Comet Linear (C/1999 S4)  

NASA Technical Reports Server (NTRS)

We propose a mechanism based on the rubble-pile hypothesis of the cometary nucleus (Weissman 1986) to explain the catastrophic breakup of comet LINEAR (C/1999 S4) observed during July-August 2000. We suggest that a solid nucleus made up of 10-100 m "cometesimals" (Weidenschilling 1997) contains a network of inter-connected voids in the inter-cometesimal regions. The production of super-volatile (i.e., species more volatile than water) gases into these voids occurs due to the thermal wave propagating through the nucleus and associated phase transitions of water ice. The network of voids provides an efficient pathway for rapid propagation of these gases within the nucleus resulting in gas pressure caused stresses over a wide regime of the nucleus. This provides a mechanism for catastrophic breakups of small cometary nuclei such as comet LINEAR (C/1999 S4) as well as for some observed cometary outbursts including those that occur at large heliocentric distances (e.g., West et al. 1991). We emphasize the importance of techniques such as radar reflection tomography and radiowave transmission tomography (e.g., Kofman et al. 1998) aboard cometary missions to determine the three dimensional structure of the nucleus in particular the extent of large scale voids.

Samarasinha, Nalin H.

2001-01-01

191

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

E-print Network

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

Misak M. Sargsian

2008-08-27

192

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

E-print Network

-induced deuteron production. Most experimental measurements with protons have used a deuterium target, and most theoreti- cal analyses have been limited to elastic pd scat- tering. The failure of the one-nucleon-exchange mechanism to fit the backward peak.... For neutrons on deuterium, the mea- sured 0 QF cross section is about equal to the sum of the corresponding free nucleon cross sec- tions, or about 6 mb/sr. " The free nd-dn elastic cross section at 0 is 0.29 mb /sr. " The QF and QE cross section data...

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

1978-01-01

193

The reaction proton deuteron yields triton pion at 470 and 590 MeV  

NASA Technical Reports Server (NTRS)

The preliminary results from a study of the deuteron (proton, positive pion)triton reaction are reported. The differential cross section for this reaction was measured for a number of center of mass angles from 37 deg to 160 deg at incident proton energies of 470 and 590 MeV. The cross sections measured at 590 MeV agree with predictions made considering a two-nucleon process. The 470 MeV data shows a peak in the backward direction which is not predicted by this mechanism.

Dollhopf, W.; Lunke, C.; Perdrisat, C. F.; Roberts, W. K.; Kitching, P.; Olsen, W. C.; Priest, J. R.

1973-01-01

194

The Soviet Breakup and U.S. Foreign Policy.  

ERIC Educational Resources Information Center

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

Lynch, Allen

1991-01-01

195

Experimental study on the breakup of charged liquid droplets  

Microsoft Academic Search

Charged droplets of water were formed at the tip of a capillary tube raised to high potential and subjected to external electric fields. The nozzle characteristics were tested to identify the different ejection modes. Under some conditions of electric field at the nozzle tip, breakup of the ejected droplets resulted. These droplets were collected on water-sensitive paper and then examined

H. M. A. Elghazaly; G. S. P. Castle

1989-01-01

196

Mantle processes during Gondwana break-up and dispersal  

Microsoft Academic Search

This paper reviews the Mesozoic continental flood basalts (CFBs) associated with the break-up and dispersal of Gondwana from 185-60 Ma, the conditions for melt generation in mantle plumes and within the continental mantle lithosphere, and possible causes for lithospheric extension. The number of CFB provinces within Gondwana is much less than the number of mantle plumes that are likely to

Chris Hawkesworth; Simon Kelley; Simon Turner; Anton Le Roex; Bryan Storey

1999-01-01

197

Age of Seychelles–India break-up  

Microsoft Academic Search

Many continental flood basalt provinces are spatially and temporally linked with continental break-up. Establishing the relative timing of the two events is a key step in determining their causal relationship. Here we investigate the example of the Deccan Traps and the separation of India and the Seychelles. Whilst there has been a growing consensus as to the age of the

J. S. Collier; V. Sansom; O. Ishizuka; R. N. Taylor; T. A. Minshull; R. B. Whitmarsh

2008-01-01

198

Break-up and droplet formation of slurry jets  

Microsoft Academic Search

Although the desirability of using slurry fuels for aerospace applications has long been recognized, the problems of slurry combustion have yet to be adequately resolved. It is pointed out that slurry fuels will not be fully utilized until the break-up, atomization, and mixing of slurries into combustion air are understood and controlled. The potential of boron containing solid fuels is

J. C. Ogg; J. A. Schetz

1983-01-01

199

Investigating primary breakup with OpenFoam: Performance and Validation  

E-print Network

Investigating primary breakup with OpenFoam: Performance and Validation A. L. Dord (Birbaud), G. M parallel simulations at GE-GRC (CHTAL) ­ application to R&D for gasification business ·The OpenFoam flow+ CSF) OpenFoam, De Villiers et al., 2004 [8] #12;6 / GE ORNL visit / 10/29/2010 Outline ·Massively

200

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

201

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

202

On causal links between flood basalts and continental breakup  

Microsoft Academic Search

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

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

1999-01-01

203

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

204

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

E-print Network

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

Alexis Diaz-Torres

2011-01-18

205

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

E-print Network

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

Diaz-Torres, Alexis

2007-01-01

206

Uncorrelated scattering approximation for the scattering and break-up of weakly bound nuclei on heavy targets  

E-print Network

The scattering of a weakly bound (halo) projectile nucleus by a heavy target nucleus is investigated. A new approach, called the Uncorrelated Scattering Approximation, is proposed. The main approximation involved is to neglect the correlation between the fragments of the projectile in the region where the interaction with the target is important. The formalism makes use of hyper-spherical harmonics, Raynal-Revay coefficients and momentum-localized wave functions to expand projectile channel wave functions in terms of products of the channel wave function of the individual fragments. Within this approach, the kinetic energy and angular momentum of each fragment is conserved during the scattering process. The elastic, inelastic and break-up S-matrices are obtained as an analytic combination involving the bound wave function of the projectile and the product of the S-matrices of the fragments. The approach is applied to describe the scattering of deuteron on $^{58}$Ni at several energies. The results are compared with experimental data and continuum-discretized coupled-channels calculations.

A. M. Moro; J. A. Caballero; J. Gómez-Camacho

2001-05-07

207

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

208

High Energy Two-Body Deuteron Photodisintegration  

SciTech Connect

The differential cross section for two­body deuteron photodisintegration was measured at photon energies between 0.8 and 4.0 GeV and center­of­mass angles theta_cm =37deg, 53deg, 70deg, and 90deg as part of CEBAF experiment E89­012. Constituent counting rules predict a scaling of this cross section at asymptotic energies. In previous experiments this scaling has surprisingly been observed at energies between 1.4 and 2.8 GeV at 90deg. The results from this experiment are in reasonable agreement with previous measurements at lower energies. The data at 70deg and 90deg show a constituent counting rule behavior up to 4.0 GeV photon energy. The 37deg and 53deg data do not agree with the constituent counting rule prediction. The new data are compared with a variety of theoretical models inspired by quantum chromodynamics (QCD) and traditional hadronic nuclear physics.

Terburg, Bart

1999-07-31

209

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

210

Deuteron injector for Peking University Neutron Imaging Facility projecta)  

NASA Astrophysics Data System (ADS)

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

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

2012-02-01

211

Timing of Depth-dependent Lithosphere Stretching on the Lofoten Continental Margin: Pre-breakup or post-breakup?  

NASA Astrophysics Data System (ADS)

Depth-dependent stretching has been observed at both non-volcanic and volcanic rifted continental margins (Driscoll and Karner 1998, Davis and Kusznir 2003). Stretching estimates, independently determined from upper crustal faulting, whole crustal thinning and post-rift lithosphere thermal subsidence, show that extension increases with depth within ˜100 km of the COB such that whole-crustal and whole-lithosphere extension is significantly greater than upper-crustal extension. A key question is whether depth-dependent stretching occurs during pre-breakup rifting or during early sea-floor spreading. Flexural backstripping and forward structural-and-stratigraphic modelling show that depth-dependent lithosphere stretching occurs on the outer part of the Norwegian volcanic rifted margin. The Lofoten segment of the margin shows very large thinning of continental lithosphere within 100 km of the COB at continental breakup time (at ˜54 Ma), while the upper crust shows no significant faulting and extension at breakup, or in the Palaeocene preceding breakup. For the southern Lofoten Margin, beta stretching-factors approaching infinity are required for the 54 Ma rift event west of the Utrøst Ridge to restore Top Basalt and the Top Tåre (˜54 Ma) to presumed sub-aerial depositional environments in the area of the marginal high. In contrast Palaeocene upper crustal beta stretching-factors are no greater than 1.1. For the mid-Lofoten margin, post-breakup subsidence with a beta stretching-factor of infinity is insufficient to generate observed margin subsidence, implying that an additional Eocene crustal thinning event younger than 54 Ma is required. The absence of significant Palaeocene extension on the Lofoten margin prior to continental breakup, and the additional Eocene subsidence supports the hypothesis that depth-dependent stretching of continental rifted margin lithosphere occurs during early sea-floor spreading rather than during pre-breakup rifting. Fluid-flow models of ocean ridge processes using analytical or finite-element solutions show divergent motion of upwelling mantle beneath the ocean ridge, which when viewed in the reference frame of the young continental margin, predict oceanward flow of lower continental crust and lithospheric mantle of the young rifted margin, so giving depth dependent stretching.

Kusznir, N. J.; Hunsdale, R.; Roberts, A. M.

2003-04-01

212

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

213

Breakup characteristics of a liquid jet in subsonic crossflow  

NASA Astrophysics Data System (ADS)

This thesis describes an experimental investigation of the breakup processes involved in the formation of a spray created by a liquid jet injected into a gaseous crossflow. This work is motivated by the utilization of this method to inject fuel in combustors and afterburners of airplane engines. This study aims to develop a better understanding of the spray breakup processes and to provide better experimental inputs to improve the fidelity of numerical models. A review of the literature in this field identified the fundamental physical processes involved in the breakup of the spray and the dependence of spray properties on operating conditions. The time taken for the liquid column to break up into ligaments and droplets, the primary breakup time and the effect of injector geometry on the spray formation processes and spray properties as the key research areas in which research done so far has been inadequate. Determination of the location where the liquid column broke up was made difficult by the presence of a large number of droplets surrounding it. This study utilizes the liquid jet light guiding technique that enables accurate measurements of this location for a wide range of operating conditions. Prior to this study, the primary breakup time was thought to be a function the density ratio of the liquid and the gas, the diameter of the orifice and the air velocity. This study found that the time to breakup of the liquid column depends on the Reynolds number of the liquid jet. This suggests that the breakup of a turbulent liquid jet is influenced by both the aerodynamic breakup processes and the turbulent breakup processes. Observations of the phenomenon of the liquid jet splitting up into two or more jets were made at some operating conditions with the aid of the new visualization technique. Finally, this thesis investigates the effect of injector geometry on spray characteristics. One injector was a round edged orifice with a length to diameter ratio of 1 and a discharge coefficient of 0.95 at the operating conditions of interest. The other injector was a sharp edged orifice with a length to diameter ratio of 10 and a discharge coefficient of 0.74 at the operating conditions of interest. It was shown that the sharp edged orifice was likely to develop cavitation bubbles beyond a flow Reynolds number of 8,000. It was found that a sharp transition in the injector can lead to the liquid column disintegrating sooner. The classical Rayleigh Taylor instabilities that are usually seen with a smooth transition in the injector were not seen in the presence of a sharp transition. The droplets produced with such an injector are larger in size and the spray penetrated deeper into the crossflow.

Gopala, Yogish

214

Quasielastic electron-deuteron scattering in the weak binding approximation  

SciTech Connect

We perform a global analysis of all available electron-deuteron quasielastic scattering data using Q^2-dependent smearing functions that describe inclusive inelastic e-d 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 section, which show particular sensitivity at x >> 1. The excellent overall agreement with data over a large range of Q^2 and x suggest a limited need for effects beyond the impulse approximation, with the exception of the very high-x or very low-Q^2 regions, where short-distance effects in the deuteron become more relevant.

Ethier, Jacob J. [William and Mary College, JLAB; Doshi, Nidhi P. [Carnegie Mellon University; Malace, Simona P. [JLAB; Melnitchouk, Wally [JLAB

2014-06-01

215

Large Q{sup 2} electrodisintegration of the deuteron  

SciTech Connect

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

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

2011-10-24

216

Inclusive and Exclusive Scatterings from Tensor Polarized Deuteron  

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

217

Evidence of Ni break-up from total production cross sections in p+Ni collisions  

E-print Network

The total production cross sections of light charged particles (LCPs), intermediate mass fragments (IMFs) and heavy reaction products of p+Ni collisions available in the literature have been compared with predictions of a two-step model in the proton beam energy range from reaction threshold up to approximately 3 GeV. Model cross sections were calculated assuming, that the reaction proceeds via an intranuclear cascade of nucleon-nucleon collisions followed by evaporation of particles from an equilibrated, heavy target residuum. The shape of the excitation functions was well described by model calculations for all reaction products. The magnitude of the cross sections was reasonably well reproduced for heavy reaction products, i.e. for nuclei heavier than Al, but the cross sections for lighter products were systematically underestimated. This fact was used as an argument in favor of a significant break-up contribution to the reaction mechanism. The present conclusions are supported by recently published results of investigations of differential cross sections in p+Ni collisions, which showed that hypothesis of the break-up of target nucleus is indispensable for a good reproduction of d2 sigma/dOmega dE for LCPs and IMFs.

A. Budzanowski; M. Fidelus; D. Filges; F. Goldenbaum; H. Hodde; L. Jarczyk; B. Kamys; M. Kistryn; St. Kistryn; St. Kliczewski; A. Kowalczyk; E. Kozik; P. Kulessa; H. Machner; A. Magiera; B. Piskor-Ignatowicz; K. Pysz; Z. Rudy; R. Siudak; M. Wojciechowski

2009-10-09

218

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

PubMed

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. PMID:21505441

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

219

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. PMID:21505441

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

220

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

221

Deuteron as a Skyrmion with a generalized mass term  

SciTech Connect

We calculate the energies of the B=1 and B=2 Skyrmions with a generalized mass term proposed in [V. B. Kopeliovich, B. Piette, and W. J. Zakrzewski, Phys. Rev. D 73, 014006 (2006).], allowing for (iso-)rotational deformations within the axially-symmetric ansatz. We show that this modification of the chiral symmetry breaking term is not sufficient to accommodate for the experimental value of the binding energy of the deuteron. Also, a computation of the different vibrational modes and energies reveals how the deuteron rigidity is affected as a function of the mass parameter D.

Bonenfant, Eric; Marleau, Luc [Departement de Physique, de Genie Physique et d'Optique, Universite Laval, Quebec, Quebec, G1K 7P4 (Canada)

2009-12-01

222

The deuteron structure function F2 with CLAS  

E-print Network

The inclusive, inelastic eD scattering cross section has been measured with the CLAS detector in Hall B of the Thomas Jefferson National Accelerator Facility (TJNAF). Combining these data and previously measured world data we have extracted Nachtmann moments of the deuteron structure function F2 in the region 0.4 < Q2 < 100 GeV2/c2. These results are published in hep-ex/0506004. The purpose of the present CLAS-Note is to tabulate the CLAS deuteron F2 data. A description of the data analysis is reported in hep-ex/0506004.

M. Osipenko; G. Ricco; S. Simula; M. Battaglieri; M. Ripani; the CLAS Collaboration

2005-09-28

223

A P + DEUTERON PROTON POLARIMETER AT 200 MEV.  

SciTech Connect

There has been concern about the analyzing power of the p-Carbon polarimeter at the end of 200 MeV LINAC of BNL. A new polarimeter based on proton-deuteron scattering was installed and we have repeated the calibration of proton-Carbon scattering at 12 degrees and 200 MeV against proton-deuteron scattering. The result is consistent with the value of A=0.62 now used to measure the beam polarization at the end of the LINAC.

HUANG,H.; ROSER,T.; ZELENSKI,A.; KURITA,K.; STEPHENSON,E.; TOOLE,R.

2002-06-02

224

Spontaneous Breakup of Extended Monodisperse Polymer Melts  

NASA Astrophysics Data System (ADS)

We apply continuum mechanical based, numerical modeling to study the dynamics of extended monodisperse polymer melts during the relaxation. The computations are within the ideas of the microstructural “interchain pressure” theory. The computations show a delayed necking resulting in a rupture, as a result of small initial sample imperfections. These ruptures agree with experimental observations.

Rasmussen, Henrik Koblitz; Yu, Kaijia

2011-09-01

225

Turning off drop breakup: surface-tension driven traveling waves  

NASA Astrophysics Data System (ADS)

With surface tension, a stretched liquid drop will breakup into several pieces to minimize its surface area. In order for a drop to break, it must create a flow whose strength necessarily depends on the drop shape. The nonlinear interaction between the velocity field and the evolving shape can result in surprising outcomes. Here we show that surface tension-driven breakup of a low-viscosity drop in a more viscous exterior can give rise to a traveling wave dynamics[1] in which a conical portion of the drop moves at a constant velocity, leaving behind a cylinder of fluid with can not break in a finite amount of time. A continuous spectrum of wave speeds are possible. Which, if any, of the traveling wave dynamics is realized in practice is an open question. [1] First noted by Zhang & Lister, unpublished results.

Zhang, Wendy; Siegel, Michael

2004-03-01

226

Liquid surface breakup of nonturbulent and turbulent liquids  

Microsoft Academic Search

An experimental study of the primary breakup in the near-injector region of large diameter (3.6-9.5 mm) liquid jets in still gases is described. The experiments involve the injection of different test liquids at a variety of velocities into various gas environments, with slug flow and fully-developed turbulent pipe flow at the jet exit. Measurements included flash photography, pulsed shadowgraphy, and

Pei-Kuan Wu

1992-01-01

227

Compound orbits break-up in constituents: an algorithm  

E-print Network

In this paper decomposition of periodic orbits in bifurcation diagrams are derived in unidimensional dynamics system $x_{n+1}=f(x_{n};r)$, being $f$ an unimodal function. We proof a theorem which states the necessary and sufficient conditions for the break-up of compound orbits in their simpler constituents. A corollary to this theorem provides an algorithm for the computation of those orbits. This process closes the theoretical framework initiated in (Physica D, 239:1135--1146, 2010).

Jesús San Martín; A. González Gómez; Ma José Moscoso; Daniel Rodríguez-Pérez

2014-02-24

228

Beam-breakup calculations for the DARHT accelerator  

Microsoft Academic Search

An induction line that will accelerate a 4-MeV, 3-kA beam of electrons to 16- to 20-MeV in 64 gaps is modeled. To suppress beam-breakup (BBU) instabilities induced by excitation of RF deflecting modes, the growth factor ? must be kept sufficiently small (e.g. <3). On prototype DARHT cavities, RF measurements have shown that the normally degenerate TM modes are split

Paul Allison; M. J. Burns; George J. Caporaso; A. G. Cole

1991-01-01

229

Semiclassical calculations of observable cross sections in breakup reactions  

SciTech Connect

We develop a semiclassical procedure to calculate breakup reaction products' angular and energy distributions in the laboratory frame of reference. The effects of the Coulomb and nuclear interaction potentials on the classical trajectories, as well as bound-bound, bound-continuum, and continuum-continuum couplings, are included. As an example we consider the {sup 8}B+{sup 58}Ni system at E{sub lab}=26 MeV and find very good agreement with the available experimental data.

Marta, H. D. [Instituto de Fisica, Facultad de Ingenieria, C.C. 30, C.P. 11000, Montevideo (Uruguay); Canto, L. F. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, C.P. 68528, 21941-972 Rio de Janeiro (Brazil); Donangelo, R. [Instituto de Fisica, Facultad de Ingenieria, C.C. 30, C.P. 11000, Montevideo (Uruguay); Instituto de Fisica, Universidade Federal do Rio de Janeiro, C.P. 68528, 21941-972 Rio de Janeiro (Brazil)

2008-09-15

230

Laser-induced break-up of water jet waveguide  

Microsoft Academic Search

In this article, an optical method to control the break-up of high-speed liquid jets is proposed. The method consists of focusing the light of a pulsed laser source into the jet behaving as a waveguide. Experiments were performed with the help of a Q-switched frequency doubled Nd:Yag laser ( ?=532 nm). The jet diameter was 48 µm and jet velocities from 100

P. Couty; Á. Spiegel; N. Vágó; B. I. Ugurtas; P. Hoffmann

2004-01-01

231

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

232

Radial electron-beam-breakup transit-time oscillator  

SciTech Connect

A new radially-driven electron-beam-breakup transit-time oscillator has been investigated analytically and through computer simulation as a compact low-impedance high-power microwave generator. In a 1MV, 50kA device 35cm in radius and 15cm long, with no external magnetic field, 5GW of extracted power and a growth rate of 0.26/ns have been observed. Theoretical maximum efficiencies are several times higher.

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

1995-01-01

233

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

234

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

NASA Technical Reports Server (NTRS)

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

Salama, Ahmed; Ling, Lisa

2005-01-01

235

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

236

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

237

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

238

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

239

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

240

A model of plate kinematics in Gondwana breakup  

NASA Astrophysics Data System (ADS)

An accurate model of relative plate motions in Gondwana breakup is based on visual fitting of seafloor isochrons and fracture zones (FZ) from the Riiser-Larsen Sea and Mozambique Basin. Used predictively, the model precisely locates kinematic markers in the West Somali Basin, which allows the conclusion that the spreading centres in the West Somali and Mozambique basins and the Riiser-Larsen Sea formed parts of the boundary between the same two plates. The locations of FZ and less well-defined isochrons from neighbouring regions are also consistent with their formation on other lengths of this same boundary and with its relocation from the West Somali Basin and northern Natal Valley to the West Enderby Basin and Lazarev Sea during chron M10n. Small independently moving plates thus played no role in the breakup of this core part of Gondwana. In an inversion procedure, the data from these areas yield more precise finite rotations that describe the history of the two plates' separation. Breakup is most simply interpreted to have occurred in coincidence with Karoo volcanism, and a reconstruction based on the rotations shows the Lebombo and Mateke-Sabi monoclines and the Mozambique and Astrid ridges as two sets of conjugate volcanic margins. Madagascar's pre-drift position can be used as a constraint to reassess the positions of India and Sri Lanka in the supercontinent.

Eagles, Graeme; König, Matthias

2008-05-01

241

Elliptic flow of deuterons in relativistic heavy-ion collisions  

E-print Network

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

Oh, Yongseok; Ko, Che Ming.

2007-01-01

242

HIGH-INTENSITY POLARIZED H-(PROTON), DEUTERON AND 3  

E-print Network

for the future deuteron Electron Dipole Moment (EDM) experiment, and the 3 He++ ion beam is a part of the experimental program for the future eRHIC (Relativistic Electron-Heavy Ion) collider. INTRODUCTION Polarized.8 ~ 3.0 keV energy, which is converted to electron-spin polarized H atoms by electron pick

243

Time reversal invariance violation in neutron-deuteron scattering  

SciTech Connect

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

Song, Young-Ho; Gudkov, Vladimir [Department of Physics and Astronomy, University of South Carolina, Columbia, South Carolina 29208 (United States); Lazauskas, Rimantas [IPHC, IN2P3-CNRS/Universite Louis Pasteur BP 28, F-67037 Strasbourg Cedex 2 (France)

2011-06-15

244

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

245

Time Reversal Invariance Violation in Neutron Deuteron Scattering  

E-print Network

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

Young-Ho Song; Rimantas Lazauskas; Vladimir Gudkov

2011-04-15

246

Incoherent pion production in neutrino-deuteron interactions  

NASA Astrophysics Data System (ADS)

Within the multiple scattering formulation, the incoherent pion production in neutrino-deuteron reactions at energies near the ? (1232 ) resonance is investigated. The calculations include an impulse term and one-loop contributions from nucleon-nucleon (N N ) and pion-nucleon (? N ) final-state interactions. The input amplitudes of ? N scattering and electroweak pion-production reaction on the nucleon are generated from a dynamical model, which describes very extensive data of ? N scattering and both the electromagnetic and the weak pion-production reactions on the nucleon. The N N scattering amplitudes are generated from the Bonn potential. The validity of the calculational procedures is established by giving a reasonably good description of the data of pion photoproduction on the deuteron. The constructed model is then applied to predict the cross sections of ? +d ??-+?++n +p and ? +d ??-+?0+p +p reactions. The importance of including the N N final-state interactions to understand the experimental data of these neutrino-deuteron reactions is demonstrated. Our results strongly suggest that the spectator approximation used in the previous analyses to extract the pion-production cross sections on the nucleon from the data on the deuteron is not valid for the ? +d ??-+?++n +p , but is a good approximation for ? +d ??-+?0+p +p .

Wu, Jia-Jun; Sato, T.; Lee, T.-S. H.

2015-03-01

247

Analysis of video imagery of the reentry and breakup of the STS-31 external tank  

NASA Technical Reports Server (NTRS)

Some of the major questions concerning the reentry and breakup of the STS-31 external tank (ET), which had a deactivated tumble valve, are addressed. The time of breakup, the altitude, and the geographic location of the ET at breakup were determined. The tumble rate was estimated to be between 8.59 deg and 8.84 deg/s. The ET broke up into at least 50 pieces 7 s after initial rupture.

Snyder, Michael W.; Pitts, David E.

1992-01-01

248

Extraction of photocapture cross sections from direct Coulomb break-up reactions  

Microsoft Academic Search

The cross section for a direct Coulomb break-up reaction may be related, within the restriction of first-order processes, to the cross section for the inverse photocapture reaction. This relationship has a possible application in determining astrophysical interesting photocapture cross sections from break-up data. By specific analysis for a particular break-up reaction, 7Li to alpha +t at 70 MeV, it is

A. C. Shotter; M. A. Nagarajan

1988-01-01

249

Coalescence and Breakup of Oppositely Charged Droplets  

PubMed Central

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

Wang, Junfeng; Wang, Bin; Qiu, Huihe

2014-01-01

250

Commissioning and operation of the deuteron injector for PKUNIFTY project  

NASA Astrophysics Data System (ADS)

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

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

2014-02-01

251

Commissioning and operation of the deuteron injector for PKUNIFTY project.  

PubMed

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

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

2014-02-01

252

Breakup time scale studied in the 8 GeV/c pi- + 197Au reaction  

E-print Network

Experimental data from the reaction of an 8.0 GeV/c pi- beam incident on a 197Au target have been analyzed in order to investigate the integrated breakup time scale for hot residues. Alpha-particle energy spectra and particle angular distributions supported by a momentum tensor analysis suggest that at large excitation energy, above 3-5 MeV/nucleon, light-charged particles are emitted prior to or at the same time as the emission of the heavy fragments. Comparison with the SMM and GEMINI models is presented. A binary fission-like mechanism fits the experimental data at low excitation energies, but seems unable to reproduce the data at excitation energies above 3-5 MeV/nucleon.

L. Pienkowski; K. Kwiatkowski; T. Lefort; W. -c. Hsi; L. Beaulieu; A. Botvina; B. Back; H. Breuer; S. Gushue; R. G. Korteling; R. Laforest; E. Martin; E. Ramakrishnan; L. P. Remsberg; D. Rowland; A. Ruangma; V. E. Viola; E. Winchester; S. J. Yennello

2000-09-16

253

About influence of the deuteron electric and magnetic plarizabities on measurement of the deuteron EDM in a storage ring  

E-print Network

In the present paper influence of tensor electric and magnetic polarizabilities on spin evolution in the resonance deuteron EDM experiment is considered in details. It is shown that besides EDM the electric and magnetic polarizabilities also contribute to the vertical spin component P_3. Moreover, the electric polarizability contributes to the P_3 component even when the deuteron EDM is supposed to be zero and thereby the electric polarizability can imitate the EDM contribution. It is shown that unlike the vertical component of the spin P_3 the component P_{33} of polarization tensor does not contain contribution from the electric polarizability, whereas contribution from the magnetic polarizability reveals only when the deuteron EDM differs from zero. Moreover, it is also shown that when the angle $\\vartheta$ between the spin direction and the vertical axis meets the condition $\\sin \\vartheta=\\sqrt{{2/3}}$ ($\\cos \\vartheta=\\sqrt{{1/3}}$), the initial value of $P_{33}$ appears $P_{33}(0)=0$. As a result, EDM contribution to the measured signal linearly growth in time starting from zero that is important for measurements. Therefore, measurement of the P_{33} component of deuteron tensor polarization seems to be of particular interest, especially because the nonzero component P_{33} appearance on its own indicates the EDM presence (in contrast to the P_3 component, which appearance can be aroused by the tensor electric polarizability, rather than EDM).

V. G. Baryshevsky

2005-10-12

254

The visibility of color breakup and a means to reduce it.  

PubMed

Color breakup is an artifact seen on displays that present colors sequentially. When the eye tracks a moving object on such a display, different colors land on different places on the retina, and this gives rise to visible color fringes at the object's leading and trailing edges. Interestingly, color breakup is also observed when the eye is stationary and an object moves by. Using a novel psychophysical procedure, we measured breakup both when viewers tracked and did not track a moving object. Breakup was somewhat more visible in the tracking than in the non-tracking condition. The video frames contained three subframes, one each for red, green, and blue. We spatially offset the green and blue stimuli in the second and third subframes, respectively, to find the values that minimized breakup. In the tracking and non-tracking conditions, spatial offsets of ?x/3 in the second subframe (where ?x is the displacement of the object in one frame) and 2?x/3 in the third eliminated breakup. Thus, this method offers a way to minimize or even eliminate breakup whether the viewer is tracking or not. We suggest ways to implement the method with real video content. We also developed a color-breakup model based on spatiotemporal filtering in color-opponent pathways in early vision. We found close agreement between the model's predictions and the experimental results. The model can be used to predict breakup for a wide variety of conditions. PMID:25527148

Johnson, Paul V; Kim, Joohwan; Banks, Martin S

2014-01-01

255

Meteoroid Streams from Sunskirter Comet Breakup  

NASA Astrophysics Data System (ADS)

In its first year of operations, the CAMS project (Cameras for Allsky Meteor Surveillance) has measured 47,000 meteoroid orbits at Earth, including some that pass the Sun as close as 0.008 AU. The population density increases significantly above perihelion distance q = 0.037 AU. Meteoroid streams are known with q about 0.1 AU. The Sun has a profound effect on comets that pass at 0.04-0.16 AU distance, called the sunskirter comets. SOHO and STEREO see families of small comets called the Marsden and Kracht groups. Sunlight is efficiently scattered by small 10-m sized fragments, making those fragments visible even when far from Earth. These comet groups are associated with meteor showers on Earth, in particular the Daytime Arietids and Delta Aquariids. All are related to 96P/Machholz, a highly inclined short-period (5.2 year) Jupiter family comet that comes to within 0.12 AU from the Sun, the smallest perihelion distance known among numbered comets. The proximity of the Sun speeds up the disintegration process, providing us a unique window on this important decay mechanism of Jupiter family comets and creating meteoroid streams. These are not the only sunskirting comets, however. In this presentation, we will present CAMS observations of the complete low-q meteoroid population at Earth and review their association with known parent bodies.

Jenniskens, P. M.

2012-12-01

256

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.

257

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

258

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

NASA Astrophysics Data System (ADS)

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

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

2012-04-01

259

Beam breakup simulation study for a high energy ERL  

NASA Astrophysics Data System (ADS)

The maximum beam current that can be accelerated in an energy recovery linac (ERL) can be severely limited by the transverse multi-pass beam breakup instability (BBU), especially in future ERL light sources with multi-GeV high energy beam energy and more than 100 mA average current. In this paper, the multi-pass BBU of such a high energy ERL is studied based on the simulation of a 3-GeV ERL light source that is proposed by KEK. This work is expected to provide a reference for future high energy ERL projects.

Chen, Si; Shimada, M.; Nakamura, N.; Huang, Sen-Lin; Liu, Ke-Xin; Chen, Jia-Er

2015-01-01

260

Radial electron-beam-breakup transit-time oscillator  

DOEpatents

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

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

1998-01-01

261

Experimental Measurements of Rayleigh Mode Liquid Jet Breakup at Microgravity  

NASA Astrophysics Data System (ADS)

Rayleigh mode breakup of a silicone oil jet in the absence of gravity was studied experimentally at the NASA Lewis Research Center's 2.2 second drop tower. The experiment consists of an apparatus to create, measure and photograph a liquid jet in the confined space of a standard drop frame (91 x 40 x 81 cm). Reynolds and Weber numbers of around 50 were achieved. Measurements of growth rates at normal gravity and microgravity were made from photographs and the growth rates are compared to the theory of Lin and Chen.

Hudman, Michael; Lin, S. P.; Connery, Brian

1998-11-01

262

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

263

Neutron structure effects in the deuteron and one neutron halos  

E-print Network

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, $F_1^{(n)} (q^2)$ and $F_2^{(n)} (q^2)$, lead to an electromagnetic potential of the neutron. Using this fact, we calculate the electromagnetic corrections to the binding energy, $B_d$, of the deuteron and a one neutron halo nucleus (11Be), by evaluating the neutron-proton and the neutron-charged core (10Be) potential, respectively. The correction to $B_d$ (~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, 11Be, the correction is close to about 2 keV.

M. Nowakowski; N. G. Kelkar; T. Mart

2006-08-29

264

Deuteron production and elliptic flow in relativistic heavy ion collisions  

SciTech Connect

The hadronic transport model ART is extended to include the production and annihilation of deuterons via the reactions BB{r_reversible}dM, where B and M stand for baryons and mesons, respectively, as well as their elastic scattering with mesons and baryons in the hadronic matter. This new hadronic transport model is used to study the transverse momentum spectrum and elliptic flow of deuterons in relativistic heavy ion collisions, with the initial hadron distributions after hadronization of the produced quark-gluon plasma taken from a blast wave model. The results are compared with those measured by the PHENIX and STAR Collaborations for Au+Au collisions at {radical}(s{sub NN})=200 GeV and also with those obtained from the coalescence model based on freeze-out nucleons in the transport model.

Oh, Yongseok [Cyclotron Institute and Physics Department, Texas A and M University, College Station, Texas 77843 (United States); Korea Institute of Science and Technology Information, Daejeon 305-806 (Korea, Republic of); Lin Ziwei [Department of Physics, East Carolina University, Greenville, North Carolina 27858 (United States); Ko, Che Ming [Cyclotron Institute and Physics Department, Texas A and M University, College Station, Texas 77843 (United States)

2009-12-15

265

GDH sum rule and double polarization experiments on the deuteron  

NASA Astrophysics Data System (ADS)

An extensive experimental program was carried out jointly at MAMI (Mainz) and ELSA (Bonn) to measure for the first time pion photo-production reactions on the nucleon in double polarization and to investigate the Gerasimov-Drell-Hearn Sum Rule. We obtained results for the proton in the energy range from about 200 MeV to 3000 MeV and for the neutron, using a deuteron target, from about 200 MeV to 1900 MeV. Most of the results on the proton have been already published. This talk is focused on the latest results on the polarized deuteron, used as a neutron target. Preliminary results on the total photo-absorption cross section, as well as on the partial reaction channels will be presented.

Braghieri, A.

266

High deuteron polarization in trityl radical doped deuterated polystyrene  

NASA Astrophysics Data System (ADS)

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

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

2013-11-01

267

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

Microsoft Academic Search

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

STANLEY M. HIRST

1984-01-01

268

Early break-up of the Norwegian Channel Ice Stream during the Last Glacial Maximum  

E-print Network

Early break-up of the Norwegian Channel Ice Stream during the Last Glacial Maximum John Inge (Sejrup et al., 2003, 2009). The time frame for the last break-up of the NCIS so far has been established erratics on the island Utsira, located in the path of the NCIS about 400 km up-flow from the LGM ice front

Briner, Jason P.

269

Break-up of a row of equally spaced immersed threads A.Y. GUNAWAN  

E-print Network

Break-up of a row of equally spaced immersed threads A.Y. GUNAWAN Jurusan Matematika, Institut-standing problem of the break-up of a cylindrical inter- face due to surface tension can be generalized-called growth rates of distur- bances. It turns out that the threads break up in specific phase patterns

Eindhoven, Technische Universiteit

270

Current status and remaining problems on the early Gondwana break-up: A geophysical perspective  

Microsoft Academic Search

The opening of the Atlantic and Indian ocean sector of teh southern ocean is in general sufficiently documented. The general geometry of the Gondwana super continent before the break-up is well constrained. Looking into details into the models, there are large gaps in our knowledge on the timing of the break-up and its relationship to the onshore volcanism. New aeromagnetic

W. Jokat

2003-01-01

271

Breakup of Copper shaped-charge jets: Experiment, numerical simulations, and analytical modeling  

E-print Network

Breakup of Copper shaped-charge jets: Experiment, numerical simulations, and analytical modeling December 2005 Experimental data on the fragmentation of copper shaped-charge jets are presented to describe shaped-charge jet breakup. The method overcomes drawbacks from exclusively numerical or analytical

Paris-Sud XI, Université de

272

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

Microsoft Academic Search

Beam instabilities due to High Order Modes (HOMs) are a concern to superconducting (SC) linacs such as the Spallation Neutron Source (SNS) linac. The effects of pulsed mode operation on transverse and longitudinal beam breakup instability are studied for H? beam in a consistent manner for the first time. Numerical simulation indicates that cumulative transverse beam breakup instabilities are not

Dong-o Jeon; L. Merminga; G. Krafft; B. Yunn; Ronald Sundelin; Jean Delayen; S. Kim; M. Doleans

2002-01-01

273

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

E-print Network

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

Muradoglu, Metin

274

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

E-print Network

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

A. Nogga; C. Hanhart

2005-11-02

275

Deuteron-equivalent and phase-equivalent interactions within light nuclei  

E-print Network

We propose a particular case of phase-equivalent transformation (PET), a deuteron-equivalent transformation (DET-PET) which leaves unchanged not only scattering phase shifts and deuteron binding energy but also the deuteron wave function. We apply DET-PET to the $NN$ interaction JISP16 and discuss modifications of the scattering wave functions. We study the manifestation of DET-PET in the binding energies of $^3$H and $^4$He nuclei and their correlation (Tjon line).

Shirokov, A M; Mazur, A I; Vary, J P; Maris, P

2012-01-01

276

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

277

Exclusive rho^0 muoproduction on transversely polarised protons and deuterons  

Microsoft Academic Search

The transverse target spin azimuthal asymmetry A_UT in hard exclusive production of rho^0 mesons was measured at COMPASS by scattering 160 GeV\\/c muons off transversely polarised protons and deuterons. The measured asymmetry is sensitive to the nucleon helicity-flip generalised parton distributions E^q, which are related to the orbital angular momentum of quarks in the nucleon. The Q^2, x_B and p_t^2

C. Adolph; M. G. Alekseev; V. Yu. Alexakhin; Yu. Alexandrov; G. D. Alexeev; A. Amoroso; A. A. Antonov; A. Austregesilo; B. Badelek; F. Balestra; J. Barth; G. Baum; Y. Bedfer; J. Bernhard; R. Bertini; M. Bettinelli; K. Bicker; J. Bieling; R. Birsa; J. Bisplinghoff; P. Bordalo; F. Bradamante; C. Braun; A. Bravar; A. Bressan; M. Buechele; E. Burtin; L. Capozza; M. Chiosso; S. U. Chung; A. Cicuttin; M. L. Crespo; S. Dalla Torre; S. Das; S. S. Dasgupta; O. Yu. Denisov; L. Dhara; S. V. Donskov; N. Doshita; V. Duic; W. Duennweber; M. Dziewiecki; A. Efremov; C. Elia; P. D. Eversheim; W. Eyrich; M. Faessler; A. Ferrero; A. Filin; M. Finger; H. Fischer; C. Franco; N. duFresnevonHohenesche; J. M. Friedrich; V. Frolov; R. Garfagnini; F. Gautheron; O. P. Gavrichtchouk; S. Gerassimov; R. Geyer; M. Giorgi; I. Gnesi; B. Gobbo; S. Goertz; S. Grabmueller; A. Grasso; B. Grube; R. Gushterski; A. Guskov; T. Guthoerl; F. Haas; D. von Harrach; F. H. Heinsius; F. Herrmann; C. Hess; F. Hinterberger; N. Horikawa; Ch. Hoeppner; N. d'Hose; S. Ishimoto; O. Ivanov; Yu. Ivanshin; T. Iwata; R. Jahn; V. Jary; P. Jasinski; R. Joosten; E. Kabuss; D. Kang; B. Ketzer; G. V. Khaustov; Yu. A. Khokhlov; Yu. Kisselev; F. Klein; K. Klimaszewski; S. Koblitz; J. H. Koivuniemi; V. N. Kolosov; K. Kondo; K. Koenigsmann; I. Konorov; V. F. Konstantinov; A. Korzenev; A. M. Kotzinian; O. Kouznetsov; M. Kraemer; Z. V. Kroumchtein; F. Kunne; K. Kurek; L. Lauser; A. A. Lednev; A. Lehmann; S. Levorato; J. Lichtenstadt; T. Liska; A. Maggiora; A. Magnon; N. Makke; G. K. Mallot; A. Mann; C. Marchand; A. Martin; J. Marzec; T. Matsuda; G. Meshcheryakov; W. Meyer; T. Michigami; Yu. V. Mikhailov; M. A. Moinester; A. Morreale; A. Mutter; A. Nagaytsev; T. Nagel; T. Negrini; F. Nerling; S. Neubert; D. Neyret; V. I. Nikolaenko; W.-D. Nowak; A. S. Nunes; A. G. Olshevsky; M. Ostrick; A. Padee; R. Panknin; D. Panzieri; B. Parsamyan; S. Paul; E. Perevalova; G. Pesaro; D. V. Peshekhonov; G. Piragino; S. Platchkov; J. Pochodzalla; J. Polak; V. A. Polyakov; J. Pretz; M. Quaresma; C. Quintans; J.-F. Rajotte; S. Ramos; V. Rapatsky; G. Reicherz; A. Richter; E. Rocco; E. Rondio; N. S. Rossiyskaya; D. I. Ryabchikov; V. D. Samoylenko; A. Sandacz; M. G. Sapozhnikov; S. Sarkar; I. A. Savin; G. Sbrizzai; P. Schiavon; C. Schill; T. Schlueter; K. Schmidt; L. Schmitt; K. Schoenning; S. Schopferer; M. Schott; W. Schroeder; O. Yu. Shevchenko; L. Silva; L. Sinha; A. N. Sissakian; M. Slunecka; G. I. Smirnov; S. Sosio; F. Sozzi; A. Srnka; L. Steiger; M. Stolarski; M. Sulc; R. Sulej; H. Suzuki; P. Sznajder; S. Takekawa; J. TerWolbeek; S. Tessaro; F. Tessarotto; L. G. Tkatchev; S. Uhl; I. Uman; M. Vandenbroucke; M. Virius; N. V. Vlassov; L. Wang; M. Wilfert; R. Windmolders; W. Wislicki; H. Wollny; K. Zaremba; M. Zavertyaev; E. Zemlyanichkina; M. Ziembicki; N. Zhuravlev; A. Zvyagin

2012-01-01

278

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

279

Measurement of inclusive spin structure functions of the deuteron  

Microsoft Academic Search

We report the results of a new measurement of spin structure functions of the deuteron in the region of moderate momentum transfer [Q2=0.27 1.3 (GeV\\/c)2] and final hadronic state mass in the nucleon resonance region (W=1.08 2.0 GeV). We scattered a 2.5 GeV polarized continuous electron beam at Jefferson Lab off a dynamically polarized cryogenic solid state target (15ND3) and

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

2003-01-01

280

Timing of depth-dependent lithosphere stretching on the S. Lofoten rifted margin offshore mid-Norway: pre-breakup or post-breakup?  

Microsoft Academic Search

Depth-dependent stretching, in which whole- crustal and whole-lithosphere extension is signi¢cantly greater than upper-crustal extension, has been observed at both non-volcanic and volcanic rifted continental margins. A key question is whether depth-dependent stretching occurs during pre-breakup rifting or during sea- £oor spreading initiation and early sea- £oor spreading. Analysis of post-breakup thermal subsidence and upper-crustal faulting show that depth-dependent lithosphere

N. J. Kusznir; R. Hunsdale; A. M. Roberts

2004-01-01

281

Break-up of New Orleans Households after Hurricane Katrina  

PubMed Central

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

Rendall, Michael S.

2011-01-01

282

Break-up channels in muon capture on 3He  

E-print Network

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

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

2014-06-26

283

Break-up channels in muon capture on He3  

NASA Astrophysics Data System (ADS)

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

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

2014-08-01

284

Deformation and breakup of viscoelastic droplets in confined shear flow  

NASA Astrophysics Data System (ADS)

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

Gupta, A.; Sbragaglia, M.

2014-08-01

285

Plethora of transitions during breakup of liquid filaments.  

PubMed

Thinning and breakup of liquid filaments are central to dripping of leaky faucets, inkjet drop formation, and raindrop fragmentation. As the filament radius decreases, curvature and capillary pressure, both inversely proportional to radius, increase and fluid is expelled with increasing velocity from the neck. As the neck radius vanishes, the governing equations become singular and the filament breaks. In slightly viscous liquids, thinning initially occurs in an inertial regime where inertial and capillary forces balance. By contrast, in highly viscous liquids, initial thinning occurs in a viscous regime where viscous and capillary forces balance. As the filament thins, viscous forces in the former case and inertial forces in the latter become important, and theory shows that the filament approaches breakup in the final inertial-viscous regime where all three forces balance. However, previous simulations and experiments reveal that transition from an initial to the final regime either occurs at a value of filament radius well below that predicted by theory or is not observed. Here, we perform new simulations and experiments, and show that a thinning filament unexpectedly passes through a number of intermediate transient regimes, thereby delaying onset of the inertial-viscous regime. The new findings have practical implications regarding formation of undesirable satellite droplets and also raise the question as to whether similar dynamical transitions arise in other free-surface flows such as coalescence that also exhibit singularities. PMID:25825761

Castrejón-Pita, José Rafael; Castrejón-Pita, Alfonso Arturo; Thete, Sumeet Suresh; Sambath, Krishnaraj; Hutchings, Ian M; Hinch, John; Lister, John R; Basaran, Osman A

2015-04-14

286

Break-up dynamics of fluctuating liquid threads  

PubMed Central

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

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

2012-01-01

287

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

288

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

289

Post-breakup solutions of Navier-Stokes and Stokes threads  

NASA Astrophysics Data System (ADS)

We consider the breakup of a fluid thread, neglecting the effect of the outside fluid (or air). After breakup, the solution of the fluid equations consists of two threads, receding rapidly from the point of breakup. We show that the bulk of each thread is described by a similarity solution of slender geometry (which we call the thread solution), but which breaks down near the tip. Near the tip of the thread the thread solution can be matched to a solution of Stokes' equation, which consists of a finger of constant spatial radius, rounded at the end. Very close to breakup, the thread solution balances inertia, viscosity, and surface tension (Navier-Stokes case). If however the fluid viscosity is large (as measured by the dimensionless Ohnesorge number), some time after breakup the thread solution consists of a balance of surface tension and viscosity only (Stokes case), and the thread profile can be described analytically.

Eggers, J.

2014-07-01

290

Molecular motions in supercooled and glassy Ibuprofen: deuteron magnetic resonance and high-resolution rheology study.  

PubMed

Using deuteron nuclear magnetic resonance, the molecular motions of specifically isotope-labeled ibuprofen were probed at the carboxylic group and at the methin group next to it. Spin relaxometry revealed slight differences between the molecular motions of the two isotopomers that are rationalized with reference to the hydrogen bonding of the COOH moiety. In the glassy state, a small-angle jump process among about four sites, related to the so-called ?-process, was identified using stimulated-echo spectroscopy. Indications for a Debye-like process, previously found to leave a weak signature in the dielectric loss, could not unambiguously be detected in magnetic resonance or shear mechanical experiments carried out for supercooled liquid ibuprofen. PMID:25785657

Bauer, S; Storek, M; Gainaru, C; Zimmermann, H; Böhmer, R

2015-04-16

291

A precise measurement of the deuteron elastic structure function A(Q^2)  

E-print Network

The A(Q^2) structure function in elastic electron-deuteron scattering was measured at six momentum transfers Q^2 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 degrees. These new precise measurements resolve discrepancies between older sets of data. They put significant constraints on existing models of the deuteron electromagnetic structure, and on the strength of isoscalar meson exchange currents.

The JLAB t20 collaboration; D. Abbott

1998-10-30

292

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

SciTech Connect

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){sup 2}. The experiment was performed at the Jefferson Laboratory in Hall C using the electron HMS Spectrometer, a specially designed deuteron magnetic channel and the recoil deuteron polarimeter POLDER. The new data determine to much larger Q{sup 2} the deuteron charge form factors G{sub C} and G{sub Q}. They are in good agreement with relativistic calculations and disagree with pQCD predictions.

David Abbott; Abdellah Ahmidouch; Heinz Anklin; Francois Arvieux; Jacques Ball; S. Beedoe; Elizabeth Beise; Louis Bimbot; Werner Boeglin; Herbert Breuer; Roger Carlini; Nicholas Chant; Samuel Danagoulian; K. Dow; Jean-Eric Ducret; James Dunne; Lars Ewell; Laurent Eyraud; Christophe Furget; Michel Garcon; Ronald Gilman; Charles Glashausser; Paul Gueye; Kenneth Gustafsson; Kawtar Hafidi; Adrian Honegger; Juerg Jourdan; Serge Kox; Gerfried Kumbartzki; L. Lu; Allison Lung; David Mack; Pete Markowitz; Justin McIntyre; David Meekins; Fernand Merchez; Joseph Mitchell; R. Mohring; Sekazi Mtingwa; Hamlet Mkrtchyan; David Pitz; Liming Qin; Ronald Ransome; Jean-Sebastien Real; Philip Roos; Paul Rutt; Reyad Sawafta; Samuel Stepanyan; Raphael Tieulent; Egle Tomasi-Gustafsson; William Turchinetz; Kelley Vansyoc; Jochen Volmer; Eric Voutier; William Vulcan; Claude Williamson; Stephen Wood; Chen Yan; Jie Zhao; Wenxia Zhao

2000-05-01

293

Determination of the threshold of the break-up of invariant tori in a class of three frequency Hamiltonian systems  

E-print Network

Determination of the threshold of the break-up of invariant tori in a class of three frequency of this paper is to determine the threshold of the break-up of an invariant torus with a speci#12;c frequency analysis for the break-up of the invariant torus. Furthermore, we obtain by these methods numerical values

Roma Tor Vergata, Università di

294

BREAK-UP DATES OF ALPINE LAKES AS PROXY DATA FOR LOCAL AND REGIONAL MEAN SURFACE AIR TEMPERATURES  

E-print Network

BREAK-UP DATES OF ALPINE LAKES AS PROXY DATA FOR LOCAL AND REGIONAL MEAN SURFACE AIR TEMPERATURES. The calendar date of ice break-up on Lej da San Murezzan, a high-altitude (1768 m a.s.l.) lake in the Swiss records from two neighbouring lakes, the potential use of the timing of spring break-up as a proxy

Livingstone, David M.

295

Break-up dynamics of fluctuating liquid threads Julien Petit, David Rivire, Hamid Kellay, and Jean-Pierre Delville  

E-print Network

1 Break-up dynamics of fluctuating liquid threads Julien Petit, David Rivière, Hamid Kellay;2 Abstract: The thinning dynamics of a liquid neck before break-up, as may happen when a drop detaches from to the thermally excited interfacial fluctuations, as for nano-jet break-up or the fragmentation of thermally

Paris-Sud XI, Université de

296

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

297

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

298

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

299

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

300

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

301

Effect of rf structure on cumulative beam breakup  

SciTech Connect

We treat the effect of rf structure of a linac beam on cumulative beam breakup in the presence of external focusing. Starting with the difference equations of Helm and Loew, we derive two forms of an exact analytic solution for coasting beams: as a sum of products of Gegenbauer polynomials involving external focusing and rf structure, and as an integral involving these same parameters. The continuous-beam limit of Neil, Hall, and Cooper is obtained as the bunch separation goes to zero. An explicit solution is presented for the steady state, including modulation of the incoming displacement, showing both stable and unstable behavior with distance. Asymptotic amplitude expressions are derived for the transient solution, which can lead to even larger beam displacements. Approximate solutions also are obtained for accelerated and decelerated beams. Comparison with numerical simulations are presented.

Gluckstern, R.L.; Cooper, R.K.; Channell, P.J.

1983-01-01

302

Break-up fragment topology in statistical multifragmentation models  

E-print Network

Break-up fragmentation patterns together with kinetic and configurational energy fluctuations are investigated in the framework of a microcanonical model with fragment degrees of freedom over a broad excitation energy range. As far as fragment partitioning is approximately preserved, energy fluctuations are found to be rather insensitive to both the way in which the freeze-out volume is constrained and the trajectory followed by the system in the excitation energy - freeze-out volume space. Due to hard-core repulsion, the freeze-out volume is found to be populated un-uniformly, its highly depleted core giving the source a bubble-like structure. The most probable localization of the largest fragments in the freeze-out volume may be inferred experimentally from their kinematic properties, largely dictated by Coulomb repulsion.

Ad. R. Raduta

2009-06-07

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

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

305

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

NASA Astrophysics Data System (ADS)

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

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

2014-03-01

306

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

SciTech Connect

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

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

2011-10-15

307

Deuteron Elastic-Scattering at 110 and 120 Mev  

E-print Network

PHYSICAL REVIEW C VOLUME 48, NUMBER 4 OCTOBER 1993 Deuteron elastic scattering at 110 and 120 MeV A. C. Betker, C. A. Gagliardi, D. R. Semon, R. E. Tribble, H. M. Xu, and A. F. Zaruba Cyclotron Institute, Texas ASM University, College Station.... 2088 BRIEF REPORTS 48 [1] Nguyen Van Sen et al. , Phys. Lett. 156B, 185 (1985). [2] A. C. Betker, C. A. Gagliardi, H. M. Xu, and A. F. Zaruba (in preparation); A. C. Betker and C. A. Gagliardi, Nucl. Instrum. Methods A283, 67 (1989). [3] W. W...

Betker, A. C.; Gagliardi, Carl A.; Semon, D. R.; Tribble, Robert E.; Xu, HM; Zaruba, A. F.

1993-01-01

308

Precise Determination of the Magnetic Moment of the Deuteron  

Microsoft Academic Search

A precision measurement of the ratio of the magnetic moment of the proton to that of the deuteron has been carried out by the magnetic resonance method. The measurements were made using mixtures of H2O and D2O and also mixtures of H2 and D2 gas. The result for the H2O:D2O mixture is while for the H2:D2 mixture muHmuD=3.2571999+\\/-0.0000012,muHmuD=3.2571990+\\/-0.0000010.

Bernard Smaller

1951-01-01

309

Parity violation in low-energy neutron-deuteron scattering  

SciTech Connect

Parity-violating effects for low-energy elastic neutron deuteron scattering are calculated for Desplanques, Donoghue, and Holstein (DDH) and effective field theory types of weak potentials in a distorted-wave Born approximation, using realistic hadronic strong interaction wave functions, obtained by solving three-body Faddeev equations in configuration space. The resulting relation between physical observables and low-energy constants can be used to fix low-energy constants from experiments. Potential model dependencies of parity-violating effects are discussed.

Song, Young-Ho; Gudkov, Vladimir [Department of Physics and Astronomy, University of South Carolina, Columbia, South Carolina 29208 (United States); Lazauskas, Rimantas [IPHC, IN2P3-CNRS/Universite Louis Pasteur, BP 28, F-67037 Strasbourg Cedex 2 (France)

2011-01-15

310

Muon Capture on the Deuteron -- The MuSun Experiment  

E-print Network

We propose to measure the rate \\Rd\\ for muon capture on the deuteron to better than 1.5% precision. This process is the simplest weak interaction process on a nucleus that can both be calculated and measured to a high degree of precision. The measurement will provide a benchmark result, far more precise than any current experimental information on weak interaction processes in the two-nucleon system. Moreover, it can impact our understanding of fundamental reactions of astrophysical interest, like solar pp fusion and the $\

V. A. Andreev; R. M. Carey; V. A. Ganzha; A. Gardestig; T. Gorringe; F. E. Gray; D. W. Hertzog; M. Hildebrandt; P. Kammel; B. Kiburg; S. Knaack; P. A. Kravtsov; A. G. Krivshich; K. Kubodera; B. Lauss; K. R. Lynch; E. M. Maev; O. E. Maev; F. Mulhauser; F. Myhrer; C. Petitjean; G. E. Petrov; R. Prieels; G. N. Schapkin; G. G. Semenchuk; M. A. Soroka; V. Tishchenko; A. A. Vasilyev; A. A. Vorobyov; M. E. Vznuzdaev; P. Winter

2010-04-11

311

The Deuteron Polarized Tensor Structure Function b1  

NASA Astrophysics Data System (ADS)

We describe Jefferson Lab E12-13-011, an inclusive deep inelastic scattering experiment to measure the leading twist deuteron tensor structure function b1 in the region 0.16 < x < 0.49 for 0.8 < Q2 < 5.0 GeV2. The experiment has been conditionally approved, contingent on target performance, with A? physics rating to run with 30 days of 11 GeV incident beam on a tensor polarized solid target in Jefferson Lab's Hall C.

Slifer, K.

2014-10-01

312

Effective Theory for Neutron-Deuteron Scattering and the Triton  

E-print Network

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

H. -W. Hammer

1999-05-18

313

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

NASA Astrophysics Data System (ADS)

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

Tsigklifis, Kostas; Pelekasis, Nikos A.

2013-03-01

314

Relativistic effects in proton-induced deuteron break-up at intermediate energies with forward emission of a fast proton pair  

E-print Network

Recent data on the reaction pD -> (pp) n with a fast forward pp pair with very small excitation energy is analyzed within a covariant approach based on the Bethe-Salpeter formalism. It is demonstrated that the minimum non-relativistic amplitude is completely masked by relativistic effects, such as Lorentz boost and the negative-energy P components in the 1S_0 Bethe-Salpeter amplitude of the pp pair.

L. P. Kaptari; B. Kampfer; S. S. Semikh; S. M. Dorkin

2002-12-16

315

Connections Between the Spring Breakup of the Southern Hemisphere Polar Vortex, Stationary Waves, and Air-sea Roughness  

NASA Technical Reports Server (NTRS)

A robust connection between the drag on surface-layer winds and the stratospheric circulation is demonstrated in NASA's Goddard Earth Observing System Chemistry-Climate Model (GEOSCCM). Specifically, an updated parameterization of roughness at the air-sea interface, in which surface roughness is increased for moderate wind speeds (4ms to 20ms), leads to a decrease in model biases in Southern Hemispheric ozone, polar cap temperature, stationary wave heat flux, and springtime vortex breakup. A dynamical mechanism is proposed whereby increased surface roughness leads to improved stationary waves. Increased surface roughness leads to anomalous eddy momentum flux convergence primarily in the Indian Ocean sector (where eddies are strongest climatologically) in September and October. The localization of the eddy momentum flux convergence anomaly in the Indian Ocean sector leads to a zonally asymmetric reduction in zonal wind and, by geostrophy, to a wavenumber-1 stationary wave pattern. This tropospheric stationary wave pattern leads to enhanced upwards wave activity entering the stratosphere. The net effect is an improved Southern Hemisphere vortex: the vortex breaks up earlier in spring (i.e., the spring late-breakup bias is partially ameliorated) yet is no weaker in mid-winter. More than half of the stratospheric biases appear to be related to the surface wind speed biases. As many other chemistry climate models use a similar scheme for their surface layer momentum exchange and have similar biases in the stratosphere, we expect that results from GEOSCCM may be relevant for other climate models.

Garfinkel, Chaim I.; Oman, Luke David; Barnes, Elizabeth A.; Waugh, Darryn W.; Hurwitz, Margaret H.; Molod, Andrea M.

2013-01-01

316

ISS Update: ATV-3 ReEntry Breakup Recorder - Duration: 11:00.  

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...

317

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

E-print Network

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

Verani, Matthieu, 1977-

2004-01-01

318

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

319

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

Microsoft Academic Search

A series of experiments aimed at understanding the influence of the liner interior surface finish on the break-up of shaped charge jets has been completed. The experiments used a standard 81-mm shaped charge design, loaded with LX-14 high explosive; incorporating high-precision copper shaped charged liners. The results indicate that a significant reduction of jet break-up time occurs between a surface

E L Baker; A J Schwartz

1999-01-01

320

Photodisintegration of the Deuteron at 20 MeV  

NASA Astrophysics Data System (ADS)

This dissertation describes the measurements of the differential cross section for the d( g? , n)p reaction performed using 20 MeV circularly polarized photons from the High Intensity gamma-ray Source (HIGS) located at the Duke Free Electron Laser Laboratory. The circularly polarized photons were incident on D2 O targets of differing lengths and the ejected neutrons were detected using the Blowfish neutron detector array. As the photodisintegration process breaks up the deuteron into only two particles, one neutron and one proton, and no other reaction channels have been conclusively demonstrated to exist below pion threshold, the measurement of the emitted neutron yields a direct measurement of the deuteron disintegration cross section. The differential cross section was expanded in terms of associated Legendre polynomial functions. Each term was simulated and fitted to the experimental data. The results were compared to the predictions of Arenhovel et al. Several systematic checks were also made on the data to help us understand the beam, target, and detector characteristics in preparation for planned experiments to test the Gerasimov-Drell-Hearn (GDH) sum rule using a dynamically polarized target to measure the spin-polarized d?(g? , n)p total cross sections. The GDH measurement is a high priority measurement for the HIGS collaboration.

Kucuker, Serpil

321

Forecasting Coastal Ice Decay and Break-up in Northern Alaska  

NASA Astrophysics Data System (ADS)

An operational forecast was developed for the break-up of coastal landfast sea ice in the Chukchi Sea off of Barrow, Alaska. The break-up process was systematically analyzed from 2000 to 2009 based on local observations of snow and ice conditions, climate records, image sequences obtained from web cameras, coastal X-band marine RADAR, and satellite imagery (mostly MODIS). Two fundamentally different break-up modes are distinguished. With the exception of 2003, 2004, and 2007, break-up of landfast sea ice was a two-step process. First, the near-shore ice cover disintegrated with ice fragments moving along shore, sheltered by grounded pressure ridges. Then, these confining ridges, typically around 1 km off-shore, broke out or melted in place. The timing of break-up of the near-shore ice cover is correlated with the downwelling solar radiation in June and July as measured at the Atmospheric Radiation Measurement (ARM) Program’s site over the nearby tundra. Break-up in 2009 was correctly predicted two weeks in advance based on the net shortwave radiation output of a 16-day regional forecast model (Weather Research and Forecasting (WRF) Model). The WRF output was converted to equivalent ARM observations based on the ground albedo assumed by the WRF model, the albedo measured at the ARM site, and the expected clear sky radiation. The downwelling shortwave radiation was also estimated from local cloud cover observations (NOAA aviation routine weather report (METAR)).

Petrich, C.; Eicken, H.; Zhang, J.; Krieger, J.

2009-12-01

322

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

323

Automated determination of auroral breakup during the substorm expansion phase using all-sky imager data  

NASA Astrophysics Data System (ADS)

This paper describes a novel method for quantitatively and routinely identifying auroral breakup following substorm onset using the Time History of Events and Macroscale Interactions during Substorms all-sky imagers. Substorm onset is characterized by a brightening of the aurora that is followed by auroral poleward expansion and auroral breakup. This breakup can be identified by a sharp increase in the auroral intensity i(t) and the time derivative of auroral intensity i(t). Utilizing both i(t) and i'(t), we have developed an algorithm for identifying the time interval and spatial location of auroral breakup during the substorm expansion phase based solely on quantifiable characteristics of the optical auroral emissions. We compare the time interval determined by the algorithm to independently identified auroral onset times from three previously published studies. In each case the time interval determined by the algorithm is within error of the onset independently identified by the prior studies. We further show the utility of the algorithm by comparing the breakup intervals determined using the automated algorithm to an independent list of substorm onset times. We demonstrate that 50% of the breakup intervals characterized by the algorithm are within the uncertainty of the times identified in the list. The quantitative description and routine identification of an interval of auroral brightening during the substorm expansion phase provides a foundation for unbiased statistical analysis of the aurora and to probe the physics of the auroral substorm and identify the processes leading to auroral substorm onset.

Murphy, Kyle R.; Miles, David M.; Watt, Clare E. J.; Rae, I. Jonathan; Mann, Ian R.; Frey, Harald U.

2014-02-01

324

Mechanical behavior of tungsten shaped charge liner materials  

SciTech Connect

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

Lassila, D.H.

1993-08-01

325

Volcanic rifted margin asymmetry and pre-breakup sag-sequences: North Atlantic examples  

NASA Astrophysics Data System (ADS)

Magma-poor margins typically show pre-breakup sag basins up to 250 km width and with a paucity of faulting. These pre-breakup sag basins are often present on only one conjugate margin leading to pronounced conjugate margin asymmetry. We address the question as to whether volcanic margins also show asymmetry and pre-breakup sag sequences. The conjugate Norwegian and East Greenland rifted continental margins, formed by North Atlantic break-up at ~ 55 Ma, display a large asymmetry. We use seismic cross-sections from the Vøring segment of the Norwegian rifted margin and its East Greenland conjugate in order to better understand the form and origin of this asymmetry. Conjugate margin asymmetry is evident in the differences in the width of the thinned continental crust, sediment thickness, and the distribution of lower crustal magmatic bodies (LCB). Conjugate margin profiles have been analysed to determine continental lithosphere thinning using flexural backstripping and reverse thermal subsidence modelling, and upper crustal stretching from fault analysis. The Vøring segment of the Norwegian rifted margin shows breakup depth-dependent lithosphere stretching and thinning where whole lithosphere stretching and thinning greatly exceeds that of the upper crust. Analysis of pre-breakup Cretaceous stratigraphy within the Vøring segment of the Norwegian margin requires subsidence greatly in excess of that indicated by upper crustal faulting and predicted from syn- and post-rift subsidence. We interpret the lack of sufficient faulting to explain Cretaceous subsidence on the Norwegian margin to indicate the presence of a pre-breakup sag basin analogous to those seen at magma-poor margins. The paucity of faulting compared with observed Cretaceous subsidence implies depth-dependent stretching and thinning of the pre-breakup continental lithosphere. Pre-breakup lithosphere subsidence on the Norwegian and Greenland continental margins has previously been attributed entirely to Jurassic and Cretaceous depth-uniform lithosphere stretching. Subsidence analysis suggests that the proposed sag basin development may initiate as early as Albian-Aptian. Lithosphere depth-dependent stretching, where lithosphere thinning greatly exceeds that of the upper crust, has been reported for continental breakup on the Norwegian margin at ~ 55 Ma. Some recent studies have proposed the presence of a failed breakup attempt during the Albian-Aptian period (110 - 100Ma). Whether depth-dependent lithosphere stretching and thinning continued through from Albian-Aptian time to breakup at ~ 55 Ma remains an important question. The breakup rupture on the west side of a broad region of depth-dependent thinned continental lithosphere may explain the asymmetry of the mid-Norwegian Greenland conjugate margins. An understand of the origins of margin asymmetry and the partitioning of breakup and pre-breakup stretching and thinning of the continental margin lithosphere is important for the prediction of subsidence and heat flow histories.

Watson, J. G.; Kusznir, N. J.; Faleide, J. I.; Tsikalas, F.; Roberts, A.

2009-04-01

326

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

327

Competition of breakup and dissipative processes in peripheral collisions at Fermi energies  

E-print Network

Heavy ion collisions in the Fermi energy regime may simultaneously show features of direct and dissipative processes. To investigate this behavior in detail, we study isotope and velocity distributions of projectile-like fragments in the reactions $^{18}$O (35 $A\\cdot$MeV) + $^9$Be($^{181}$Ta) at forward angles. We decompose the experimental velocity distributions empirically into two contributions: a direct, `breakup' component centered at beam velocity and a dissipative component at lower velocities leading to a tail of the velocity distributions. The direct component is interpreted in the Goldhaber model, and the widths of the velocity distributions are extracted. The dissipative component is then successfully described by transport calculations. The ratio of the yields of the direct and the dissipative contributions can be understood from the behavior of the deflection functions. The isotope distributions of the dissipative component agree qualitatively with the data, but the modification due to secondary de-excitation needs to be considered. We conclude, that such reactions are of interest to study the equilibration mechanism in heavy ion collisions.

T. I. Mikhailova; A. G. Artyukh; M. Colonna; M. Di Toro; B. Erdemchimeg; G. Kaminski; I. N. Mikhailov; Yu. M. Sereda; H. H. Wolter

2008-11-20

328

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

329

Break-up of a falling drop containing dispersed particles  

NASA Astrophysics Data System (ADS)

The general purpose of this paper is to investigate some consequences of the randomness of the velocities of interacting rigid particles falling under gravity through viscous fluid at small Reynolds number. Random velocities often imply diffusive transport of the particles, but particle diffusion of the conventional kind exists only when the length characteristic of the diffusion process is small compared with the distance over which the particle concentration is effectively uniform. When this condition is not satisfied, some alternative analytical description of the dispersion process is needed. Here we suppose that a dilute dispersion of sedimenting particles is bounded externally by pure fluid and enquire about the rate at which particles make outward random crossings of the (imaginary) boundary. If the particles are initially distributed with uniform concentration within a spherical boundary, we gain the convenience of approximately steady conditions with a velocity distribution like that in a falling spherical drop of pure liquid. However, randomness of the particle velocities causes some particles to make an outward crossing of the spherical boundary and to be carried round the boundary and thence downstream in a vertical ‘tail’. This is the nature of break-up of a falling cloud of particles.

Nitsche, J. M.; Batchelor, G. K.

1997-06-01

330

Panjal Paleomagnetism: Implications for Early Permian Gondwana break-up  

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

331

Break-up and Coalescence in Liquid/Liquid Flows  

NASA Astrophysics Data System (ADS)

Break-up and coalescence transitions in mixtures of oil- and water-based fluids are investigated experimentally with the goal of understanding the underlying dynamics and of eventually developing accurate numerical models for practical applications such as transport, mixing, and separation of petroleum, chemical, and waste streams. Several geometries are examined: natural and periodically forced jets flowing into and breaking up in an ambient, drops impacting and eventually coalescing at a quiescent interface, and coalescing drop pairs. Refractive index matching and laser induced fluorescence are employed to obtain clear images of the interfaces and interior volumes within each flow. Real-time flow sequences of planar fields are acquired using a high-frequency laser and camera system, and the resulting images are analyzed to determine interfacial behavior as well as two- and three-component velocity fields. In the jet flow, the effects of fluid viscosity ratio, Reynolds number, Strouhal number, and Ohnesorge number on the flow dynamics will be discussed. In the coalescing flows, the effects of viscosity ratio, impact Weber number and offset distance will be discussed. Finally, some of the experimental results will be compared with the results of numerical simulations incorporating transition models and adaptive grids.

Longmire, Ellen K.

2004-11-01

332

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

333

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

PubMed

The purpose of the present study was to investigate the relationship between using the social networking site known as Facebook and negative interpersonal relationship outcomes. A survey of 205 Facebook users aged 18-82 was conducted using a 16-question online survey to examine whether high levels of Facebook use predicted negative relationship outcomes (breakup/divorce, emotional cheating, and physical cheating). It was hypothesized that those with higher levels of Facebook use would demonstrate more negative relationship outcomes than those with lower use. The study then examined whether these relationships were mediated by Facebook-related conflict. Furthermore, the researchers examined length of relationship as a moderator variable in the aforementioned model. The results indicate that a high level of Facebook usage is associated with negative relationship outcomes, and that these relationships are indeed mediated by Facebook-related conflict. This series of relationships only holds for those who are, or have been, in relatively newer relationships of 3 years or less. The current study adds to the growing body of literature investigating Internet use and relationship outcomes, and may be a precursor to further research investigating whether Facebook use attributes to the divorce rate, emotional cheating, and physical cheating. PMID:23745615

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

2013-10-01

334

Droplet collisions after liquid jet breakup in microgravity conditions  

NASA Astrophysics Data System (ADS)

The droplet dynamics and collisions after a liquid jet breakup have been experimentally studied in low gravity conditions. An experimental setup was designed in order to be used at the I.N.T.A. Drop Tower, which allows for 2.1 seconds of microgravity. The dynamics of distilled water jets injected into a rectangular tank was recorded by means of a high-speed video camera. Observations of the droplet trajectories showed a conical shape of the liquid jet caused by droplet collisions just after detachment from the liquid jet. The detached droplets initially follow straight paths at constant velocity in the direction of injection. Deviation of these trajectories is a consequence of the collision between two droplets with an impact parameter slightly different from zero. The collision between two droplets can give rise to coalescence or bouncing between droplets depending on the droplet velocity difference and impact parameter. At low values of the relative velocity, the collision leads to coalescence between droplets, while at higher values the collision results in bouncing between droplets.

Suñol, F.; González-Cinca, R.

2011-12-01

335

Electric field induced sheeting and breakup of dielectric liquid jets  

NASA Astrophysics Data System (ADS)

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

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

2014-01-01

336

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

SciTech Connect

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

Lechman, Jeremy B.

2010-10-01

337

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

338

Polarization observables in lepton-deuteron elastic scattering including the lepton mass  

NASA Astrophysics Data System (ADS)

Expressions for the unpolarized differential cross section and for various polarization observables in the lepton-deuteron elastic scattering, ? +D ?? +D ,? =e ,? ,? , have been obtained in the one-photon-exchange approximation, taking into account the lepton mass. Polarization effects have been investigated for the case of a polarized lepton beam and polarized deuteron target which can have vector or tensor polarization. Numerical estimations of the lepton mass effects have been done for the unpolarized differential cross section and for some polarization observables and applied to the case of low-energy muon deuteron elastic scattering.

Gakh, G. I.; Gakh, A. G.; Tomasi-Gustafsson, E.

2014-12-01

339

Determination of the Azimuthal Asymmetry of Deuteron Photodisintegration in the Energy Region E{sub {gamma}} = 1.1 - 2.3 GeV  

SciTech Connect

Deuteron photodisintegration is a benchmark process for the investigation of the role of quarks and gluons in nuclei. Existing theoretical models of this process describe the available cross sections with the same degree of success. Therefore, spin-dependent observables are crucial for a better understanding of the underlying dynamical mechanisms. However, data on the induced polarization (P{sub y}), along with the polarization transfers (C{sub x'} and C{sub z'} ), have been shown to be insensitive to differences between theoretical models. On the other hand, the beam-spin asymmetry {Sigma} is predicted to have a large sensitivity and is expected to help in identifying the energy at which the transition from the hadronic to the quark-gluon picture of the deuteron takes place. Here, the work done to determine the experimental values of the beam-spin asymmetry in deuteron photodisintegration for photon energies between 1.1 ? 2.3 GeV is presented. The data were taken with the CLAS at the Thomas Jefferson National Accelerator Facility during the g13 experiment. Photons with linear polarization of ~80% were produced using the coherent bremsstrahlung facility in Hall B. The work done by the author to calibrate a specific detector system, select deuteron photodisintegration events, study the degree of photon polarization, and finally determine the azimuthal asymmetry and any systematic uncertainties associate with it, is comprehensively explained. This work shows that the collected data provide the kinematic coverage and statistics to test the available QCD-based models. The results of this study show that the available theoretical models in their current state do not adequately predict the azimuthal asymmetry in the energy region 1.1 ? 2.3 GeV.

Nicholas Zachariou

2012-05-20

340

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

Microsoft Academic Search

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

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

341

Implicit negative evaluations about ex-partner predicts break-up adjustment: The brighter side of dark cognitions  

Microsoft Academic Search

Using a subliminal priming lexical decision task, the present research investigated whether individuals who show negative implicit evaluations of an ex-partner immediately after a break-up show superior post-break-up emotional adjustment. As expected, individuals whose reaction times indicated negative implicit evaluations of their ex-partner showed reduced depressive affect immediately after the break-up. Individuals who did not initiate their break-up demonstrated less

Christopher P. Fagundes

2011-01-01

342

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

343

Covariant Spectator Theory of np scattering: Deuteron Quadrupole Moment  

DOE PAGESBeta

The deuteron quadrupole moment is calculated using two CST model wave functions obtained from the 2007 high precision fits to $np$ scattering data. Included in the calculation are a new class of isoscalar $np$ interaction currents automatically generated by the nuclear force model used in these fits. The prediction for model WJC-1, with larger relativistic P-state components, is $2.5\\%$ smaller that the experiential result, in common with the inability of models prior to 2014 to predict this important quantity. However, model WJC-2, with very small P-state components, gives agreement to better than 1\\%, similar to the results obtained recently from $\\chi$EFT predictions to order N$^3$LO.

Gross, Franz

2015-01-01

344

Deuteron distribution in nuclei and the Levinger's factor  

NASA Astrophysics Data System (ADS)

We compute the distribution of quasideuterons in doubly closed shell nuclei. The ground states of 16O and 40Ca are described in ls coupling using a realistic Hamiltonian including the Argonne v'8 and the Urbana IX models of two- and three-nucleon potentials, respectively. The nuclear wave function contains central and tensor correlations, and correlated basis functions theory is used to evaluate the distribution of neutron-proton pairs, having the deuteron quantum numbers, as a function of their total momentum. By computing the number of deuteronlike pairs we are able to extract Levinger’s factor and compare to both the available experimental data and the predictions of the local density approximation, based on nuclear matter estimates. The agreement with the experiments is excellent, whereas the local density approximation is shown to sizably overestimate Levinger’s factor in the region of the medium nuclei.

Benhar, O.; Fabrocini, A.; Fantoni, S.; Illarionov, A. Yu.; Lykasov, G. I.

2003-01-01

345

P and T odd effects in deuteron in the Reid potential  

E-print Network

The $P$ and $T$ odd deuteron multipoles are calculated in the Reid nucleon-nucleon potential in the chiral limit $m_{\\pi}\\to 0$. The contact current generated by the $\\pi$-meson exchange does not contribute to the anapole moment. The contact current generated by the vector meson exchange is negligible in comparison with other contributions of vector mesons. The result for the deuteron electric dipole moment is of great interest because of the experiment on its measurement discussed in Brookhaven. The deuteron photodisintegration cross section asymmetry at the threshold is also calculated. It is shown that its value strongly depends on the tensor forces and d-wave contribution to the deuteron wave function.

R. V. Korkin

2005-04-27

346

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

347

Continental breakup and its effect on MORB chemistry  

NASA Astrophysics Data System (ADS)

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

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

2012-12-01

348

The oil body formation and breakup in the compound vortex  

NASA Astrophysics Data System (ADS)

The flows in the Ocean and Atmosphere combine different types of motion: streams, jets, wakes, vortices and waves. When flows transport solid bodies or immiscible admixtures picturesque flow patterns are revealed and indicated the type of flow. Different spiral patterns visualize vortex flow structure. In experiments is studied the transport of finite volumes of immiscible admixture introduced on the free surface of water drawn into the vortex motion in the vertical cylindrical container. The basic medium was tap water, preliminary degasified to make the visualization less difficult. The fixed volume of immiscible admixture (castor or sunflower oil) is introduced on the quiescent free surface of water inside the cylindrical container. The generation of compound vortex in the cylindrical container started after all the disturbances caused by deposition of the oil volume are damped. In compound vortex the flow oil patch with smooth boundary placed onto free surface is transformed into a set of spiral arms and separate drops contacting with the central oil volume. The droplets are separated from the central spot and slowly travel towards the container sidewall. With time, the spot is transformed into pronounced spiral arms. The most part of oil under the influence of vortex flow is gathered into the central volume contacting with the free surface. This volume is called "the oil body". On the lower frequencies of disk rotation and respectively slow flow gyration the oil body has smooth boundaries with water and air. The growth of disk rotation frequency leads to more pronounced deformation of the contact surface between liquid and air, the boundary of the oil body and water then is covered by small pimples. At the further increase of disk rotation frequency the oil body comes to the breakup, the water-oil boundary become irregular and on the lowest part of the oil body the analog of foam appears (the water-oil emulsion). The work is supported by Ministry of Education and Science RF (Goscontract No. 16.518.11.7059).

Chaplina, T. O.; Stepanova, E. V.

2012-04-01

349

Measurements of the Deuteron Elastic Structure Function A(Q²) for 0.7  

Microsoft Academic Search

The deuteron elastic structure function A(Q²) has been extracted in the range 0.7 < or = Q² < or = 6.0 (GeV\\/c)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

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. dHose; 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; 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

1999-01-01

350

Angular distributions of deuterons from 6Li(12C, d)16O  

Microsoft Academic Search

The angular distributions of deuterons from the reaction 6Li(12C, d)16O* leading to the ground state and the first eight excited states of 16O have been measured at a c.m. energy of 7 MeV. The angular distributions of deuterons leading to the 3rd, 4th and 5th excited states have also been measured at 8 MeV, and excitation functions for these levels

H. M. Loebenstein; D. W. Mingay; H. Winkler; C. S. Zaidins

1967-01-01

351

Development of high intensity deuteron ion source for the fusion intense neutron source  

Microsoft Academic Search

A high intensity deuteron ion source has been developed in order to increase the neutron flax from the D-T neutron source for Fusion Neutronics Source at JAERI. It is possible to extract more than 50 mA of deuteron beam at the beam energy of 50 keV. The lifetime of the tungsten filaments utilized in the ion source has been achieved

M. Kinsho; M. Sugimoto; M. Seki; H. Oguri; Y. Okumura

2000-01-01

352

Nuclear activation measurements of High energy deuterons from a small plasma focus  

NASA Astrophysics Data System (ADS)

High-energy deuterons from a small (1.7 kJ) plasma focus device were studied by nuclear activation of a boron-carbide target. The ratio of 10B( d,n) 11C and 12C( d,n) 13N yields indicates a deuteron spectrum decreasing rapidly between 400 keV and 1 MeV. This spectrum could take the form of dN/dE?E with n?9.

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

2009-02-01

353

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

NASA Technical Reports Server (NTRS)

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

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

2010-01-01

354

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

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

355

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

PubMed

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

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

2001-05-18

356

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

357

Effect of breakup in the fusion of {sup 7}Li with {sup 165}Ho  

SciTech Connect

The effect of {sup 7}Li breakup on the fusion of the {sup 7}Li+{sup 165}Ho system has been investigated using the continuum-discretized coupled channels (CDCC) calculations. Coupling of the breakup channel leads to a large enhancement in the total fusion cross sections at energies below the Coulomb barrier, while it leads to a small reduction of the fusion cross sections at above barrier energies. A large contribution to this enhancement is found because of dipole couplings arising from the L=0 continuum excitation of {sup 7}Li to its ground state. The dynamic polarization potential generated by the {sup 7}Li breakup couplings is found to have an attractive real part at below barrier energies, due to the dominance of dipole (E1) couplings. Inelastic couplings due to the target deformation are found to have negligible effects on the fusion cross section.

Jha, V.; Kailas, S. [Nuclear Physics Division, Bhabha Atomic Research Centre, Mumbai 400 085 (India)

2009-09-15

358

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

NASA Astrophysics Data System (ADS)

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

Kulkarni, V.; Sojka, P. E.

2014-07-01

359

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

SciTech Connect

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

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

2014-07-15

360

Geometry and tunneling dynamics of CHD2 groups in aspirin: A single-crystal deuteron nuclear magnetic resonance study  

NASA Astrophysics Data System (ADS)

CHD2 groups in aspirin are studied by single-crystal deuteron NMR at temperatures between 7 and 290 K. They perform stochastic reorientations which are governed by a rotational potential possessing three wells, two of which are almost equally deep whereas the third is significantly higher. The three minima of the rotational potential are separated by angles substantially different from 120°. Still, at least in the two lower wells, the geometry of the CHD2 groups is close to that of a symmetric rotor. By selective magnetization transfer experiments, the incoherent tunneling rate between the two lower potential wells is determined. At temperatures below 15 K, Raman processes are the dominating rotor-phonon coupling mechanism, while at higher temperatures, thermally activated processes with activation energies close to the total potential height prevail.

Detken, A.; Zimmermann, H.

1998-10-01

361

A Paleo-Mesoproterozoic supercontinent: assembly, growth and breakup  

NASA Astrophysics Data System (ADS)

Geological and paleomagnetic data support the hypothesis that a Paleo-Mesoproterozoic supercontinent, referred to as Columbia, existed before the formation of Rodinia. This pre-Rodinia supercontinent was assembled along global-scale 2.1-1.8 Ga collisional orogens and contained almost all of Earth's continental blocks. Following its final assembly at ˜1.8 Ga, the supercontinent Columbia underwent long-lived (1.8-1.3 Ga), subduction-related growth via accretion at key continental margins, forming a 1.8-1.3 Ga large magmatic accretionary belt along the present-day southern margin of North America, Greenland and Baltica. It includes the 1.8-1.7 Ga Yavapai, Central Plains and Makkovikian Belts, 1.7-1.6 Ga Mazatzal and Labradorian Belts, 1.5-1.3 Ga St. Francois and Spavinaw Belts and 1.3-1.2 Ga Elzevirian Belt in North America; the 1.8-1.7 Ga Ketilidian Belt in Greenland; and the 1.8-1.7-Transscandinavian Igneous Belt, 1.7-1.6 Ga Kongsberggian-Gothian Belt, and 1.5-1.3 Ga Southwest Sweden Granitoid Belt in Baltica. Other cratonic blocks also underwent marginal outgrowth at about the same time. In South America, a 1.8-1.3 Ga accretionary zone occurs along the western margin of the Amazonia Craton, represented by the Rio Negro, Juruena and Rondonian Belts. In Australia, 1.8-1.5 Ga accretionary magmatic belts, including the Arunta, Mt. Isa, Georgetown, Coen and Broken Hill Belts, occur surrounding the southern and eastern margins of the North Australia Craton and the eastern margin of the Gawler Craton. In China, a 1.8-1.4 Ga accretionary magmatic zone, called the Xiong'er belt (Group), extends along the southern margin of the North China Craton. Fragmentation of this supercontinent began about 1.6 Ga ago, associated with continental rifting along the western margin of Laurentia (Belt-Purcell Supergroup), southern margin of Baltica (Telemark Supergroup), southeastern margin of Siberia (Riphean aulacogens), northwestern margin of South Africa (Kalahari Copper Belt), and northern margin of North China (Zhaertai-Bayan Obo Belt). The fragmentation corresponded with widespread anorogenic magmatic activity, forming anorthosite-mangerite-charnockite-granite (AMCG) suites in North America, Baltica, Amazonia and North China, and continued until the final breakup of the supercontinent at about 1.3-1.2 Ga, marked by the emplacement of the 1.27 Ga MacKenzie and 1.24 Ga Sudbury mafic dike swarms in North America.

Zhao, Guochun; Sun, Min; Wilde, Simon A.; Li, Sanzhong

2004-09-01

362

Post-breakup tectonics in southeast Brazil from thermochronological data and combined inverse-forward thermal history modeling  

E-print Network

with Andean tectonics and those in NE Brazil leads us to assume a plate-wide compressional stressPost-breakup tectonics in southeast Brazil from thermochronological data and combined inverse. Riccomini, and C. Gautheron (2012), Post-breakup tectonics in southeast Brazil from thermochronological data

Paris-Sud XI, Université de

363

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

364

Break-up phenomena of liquid metal thin film induced by high electric current  

E-print Network

The room temperature liquid metal related electronics has been found important in a wide variety of emerging areas over the past few years. However, its failure features under high electrical current densities are not clear until now. Here we show that a liquid metal thin film would break-up as the applied current increases to a critical magnitude. The break-up phenomenon is attributed to be caused by the so-called electromigration effect. This problem could be one of the major hurdles that must be tackled with caution in the research and application of future liquid metal film electronics.

Rongchao Ma; Cangran Guo; Yixin Zhou; Jing Liu

2013-09-03

365

Approximate renormalization for the break-up of invariant tori with three frequencies  

E-print Network

We construct an approximate renormalization transformation for Hamiltonian systems with three degrees of freedom in order to study the break-up of invariant tori with three incommensurate frequencies which belong to the cubic field $Q(\\tau)$, where $\\tau^3+\\tau^2-2\\tau-1=0$. This renormalization has two fixed points~: a stable one and a hyperbolic one with a codimension one stable manifold. We compute the associated critical exponents that characterize the universality class for the break-up of the invariant tori we consider.

C. Chandre; R. S. MacKay

2000-01-17

366

Kinetic energy spectra for fragments and break-up density in multifragmentation  

E-print Network

We investigate the possibility, in nuclear fragmentation, to extract information on nuclear density at break-up from fragment kinetic energy spectra using a simultaneous scenario for fragment emission. The conclusions we derive are different from the recently published results of Viola et al. [Phys. Rev. Lett. 93, (2004), 132701] assuming a sequential fragment emission and claiming that the experimentally observed decrease of peak centroids for kinetic energy spectra of fragments with increasing bombarding energy is due to a monotonic decrease of the break-up density.

Ad. R. Raduta; B. Borderie; E. Bonnet; N. Le Neindre; S. Piantelli; M. F. Rivet

2005-07-13

367

Dye Tracers for Characterizing Breakup in Arctic Rivers: An Old School Solution for a Modern Conundrum  

NASA Astrophysics Data System (ADS)

Discharge in arctic rivers is often near its annual maximum during spring breakup. However, the presence swiftly moving ice at this time of year leads to unsafe boating conditions, thus complicating the collection of discharge information through modern methods such as acoustic Doppler current profiling (ADCP). In this paper, we report the results of a study designed to evaluate the breakup discharge of Alaska's Itkillik River using Rhodamine WT, a fluorescent dye. Notable advantages of the method included the ability to inject and collect the dye without entering the water. A disadvantage of the method was the confounding effects of turbidity and/or suspended solids.

Schnabel, W.; Stephan, N.; Toniolo, H. A.; Kane, D. L.

2011-12-01

368

Ground-state configuration of neutron-rich Aluminum isotopes through Coulomb Breakup  

NASA Astrophysics Data System (ADS)

Neutron-rich 34,35Al isotopes have been studied through Coulomb excitation using LAND-FRS setup at GSI, Darmstadt. The method of invariant mass analysis has been used to reconstruct the excitation energy of the nucleus prior to decay. Comparison of experimental CD cross-section with direct breakup model calculation with neutron in p3/2 orbital favours 34Al(g.s)??p3/2 as ground state configuration of 35Al. But ground state configuration of 34Al is complicated as evident from ?-ray spectra of 33Al after Coulomb breakup of 34Al.

Chakraborty, S.; Datta Pramanik, U.; Aumann, T.; Beceiro, S.; Boretzky, K.; Caesar, C.; Carlson, B. V.; Catford, W. N.; Chatterjee, S.; Chartier, M.; Cortina-Gil, D.; De Angelis, G.; Gonzalez-Diaz, D.; Emling, H.; Diaz Fernandez, P.; Fraile, L. M.; Ershova, O.; Geissel, H.; Heil, M.; Jonson, B.; Kelic, A.; Johansson, H.; Kruecken, R.; Kroll, T.; Kurcewicz, J.; Langer, C.; Le Bleis, T.; Leifels, Y.; Munzenberg, G.; Marganiec, J.; Nociforo, C.; Najafi, A.; Panin, V.; Paschalis, S.; Pietri, S.; Plag, R.; Rahaman, A.; Reifarth, R.; Ricciardi, V.; Rossi, D.; Ray, J.; Simon, H.; Scheidenberger, C.; Typel, S.; Taylor, J.; Togano, Y.; Volkov, V.; Weick, H.; Wagner, A.; Wamers, F.; Weigand, M.; Winfield, J. S.; Yakorev, D.; Zoric, M.

2014-03-01

369

Experimental deuteron momentum distributions with reduced final state interactions  

NASA Astrophysics Data System (ADS)

This dissertation presents a study of the D( e, e'p)n reaction carried out at the Thomas Jefferson National Accelerator Facility (Jefferson Lab) for a set of fixed values of four-momentum transfer Q 2 = 2.1 and 0.8 (GeV/c)2 and for missing momenta pm ranging from pm = 0.03 to pm = 0.65 GeV/c. The analysis resulted in the determination of absolute D(e,e' p)n cross sections as a function of the recoiling neutron momentum and it's scattering angle with respect to the momentum transfer [vector] q. The angular distribution was compared to various modern theoretical predictions that also included final state interactions. The data confirmed the theoretical prediction of a strong anisotropy of final state interaction contributions at Q2 of 2.1 (GeV/c)2 while at the lower Q2 value, the anisotropy was much less pronounced. At Q2 of 0.8 (GeV/c)2, theories show a large disagreement with the experimental results. The experimental momentum distribution of the bound proton inside the deuteron has been determined for the first time at a set of fixed neutron recoil angles. The momentum distribution is directly related to the ground state wave function of the deuteron in momentum space. The high momentum part of this wave function plays a crucial role in understanding the short-range part of the nucleon-nucleon force. At Q2 = 2.1 (GeV/c)2, the momentum distribution determined at small neutron recoil angles is much less affected by FSI compared to a recoil angle of 75°. In contrast, at Q2 = 0.8 (GeV/c)2 there seems to be no region with reduced FSI for larger missing momenta. Besides the statistical errors, systematic errors of about 5--6 % were included in the final results in order to account for normalization uncertainties and uncertainties in the determi- nation of kinematic veriables. The measurements were carried out using an electron beam energy of 2.8 and 4.7 GeV with beam currents between 10 to 100 ? A. The scattered electrons and the ejected protons originated from a 15cm long liquid deuterium target, and were detected in conicidence with the two high resolution spectrometers of Hall A at Jefferson Lab.

Khanal, Hari P.

370

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

NASA Astrophysics Data System (ADS)

Numerical 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

371

Continental break-up history of a deep magma-poor margin based on seismic reflection data (north-eastern Gulf of Aden margin, offshore Oman)  

E-print Network

1 Continental break-up history of a deep magma-poor margin based on seismic reflection data (north.autin@gmail.com Abbreviated title: Continental break-up history of the north-eastern Gulf of Aden SUMMARY Rifting between, where the continental break-up finally occurred. Initial seafloor spreading was followed by post

Paris-Sud XI, Université de

372

Asymptotic normalization coefficients and spectroscopic factors from deuteron stripping reactions  

NASA Astrophysics Data System (ADS)

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

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

2014-10-01

373

Final state interaction in lepton scattering off deuterons  

E-print Network

The role of the final state interactions (FSI) in inclusive electro disintegration of the deuteron, D(e,e')X, is being investigated within different approaches. A detailed comparison between an improved Glauber method and the standard Schroedinger approach is presented. It is shown that both methods become inadequate at large values of Q^2, where the virtuality of the hit nucleon after photon absorbtion is very high. The concept of finite formation time (FFT) required by the hit hadron to reach its asymptotic form is introduced by a Feynman diagram approach and by explicitly taking into account the dependence of the ejected nucleon on its virtuality. The approach has been applied both at x_{Bj} ~= 1, as well as in the so called cumulative region i.e. at x_{Bj} > 1. Numerical calculations show that the effects of the FFT almost completely cancel the contribution from rescattering processes. In the cumulative region the color transparency or finite formation time effects become fairly visible.

Kaptari, L P

2002-01-01

374

Muon induced deuteron disintegration in three-dimensions  

NASA Astrophysics Data System (ADS)

We present a three-dimensional (3D) description of muon induced deuteron disintegration. This reaction is treated as the decay of the muonic atom with the muon initially on the lowest K shell. Our aim is to calculate the total and differential decay rates. We work in momentum space and use 3D momentum eigenstates directly. This approach allowed us to calculate the appropriate nuclear matrix elements, necessary building blocks for the differential decay rate, in a single step. For contrast - in classical calculations many partial-waves have to be taken into account. We achieved a very good agreement between the 3D and partial-wave methods for calculations that involve single-nucleon currents. Our result for the total decay rate is also in agreement with experimental values, though these are not very precise. This success motivates us to also include two-nucleon current contributions that include the meson exchange currents. Additionally, our formalism can also be applied to other, so far poorly described, processes like: ? +3 He? ? + n + d or ? +3 He ? ? + n + n + p.

Topolnicki, Kacper; Golak, Jacek; Skibi?ski, Roman; Marcucci, Laura Elisa; Wita?a, Henryk; Eldeen Elmeshneb, Alaa

2014-11-01

375

Compton Scattering from the Deuteron and Extracted Neutron Polarizabilities  

E-print Network

Differential cross sections for Compton scattering from the deuteron were measured at MAX-lab for incident photon energies of 55 MeV and 66 MeV at nominal laboratory angles of $45^\\circ$, $125^\\circ$, and $135^\\circ$. Tagged photons were scattered from liquid deuterium and detected in three NaI spectrometers. By comparing the data with theoretical calculations in the framework of a one-boson-exchange potential model, the sum and difference of the isospin-averaged nucleon polarizabilities, $\\alpha_N + \\beta_N = 17.4 \\pm 3.7$ and $\\alpha_N - \\beta_N = 6.4 \\pm 2.4$ (in units of $10^{-4}$ fm$^3$), have been determined. By combining the latter with the global-averaged value for $\\alpha_p - \\beta_p$ and using the predictions of the Baldin sum rule for the sum of the nucleon polarizabilities, we have obtained values for the neutron electric and magnetic polarizabilities of $\\alpha_n= 8.8 \\pm 2.4$(total) $\\pm 3.0$(model) and $\\beta_n = 6.5 \\mp 2.4$(total) $\\mp 3.0$(model), respectively.

M. Lundin; J. -O. Adler; M. Boland; K. Fissum; T. Glebe; K. Hansen; L. Isaksson; O. Kaltschmidt; M. Karlsson; K. Kossert; M. I. Levchuk; P. Lilja; B. Lindner; A. I. L'vov; B. Nilsson; D. E. Oner; C. Poech; S. Proff; A. Sandell; B. Schröder; M. Schumacher; D. A. Sims

2003-06-13

376

Compton Scattering from the Deuteron below Pion-Production Threshold  

E-print Network

Differential cross sections for elastic scattering of photons from the deuteron have recently been measured at the Tagged-Photon Facility at the MAX IV Laboratory in Lund, Sweden. These first new measurements in more than a decade further constrain the isoscalar electromagnetic polarizabilities of the nucleon and provide the first-ever results above 100 MeV, where the sensitivity to the polarizabilities is increased. We add 23 points between 70 and 112 MeV, at angles 60deg, 120deg and 150deg. Analysis of these data using a Chiral Effective Field Theory indicates that the cross sections are both self-consistent and consistent with previous measurements. Extracted values of \\alpha_s = [12.1 +/- 0.8(stat) +/- 0.2(BSR) +/- 0.8(th)] X 10^{-4} fm^3 and \\beta_s = [2.4 +/- 0.8(stat) +/- 0.2(BSR) +/- 0.8(th)] X 10^{-4} fm^3 are obtained from a fit to these 23 new data points. This paper presents in detail the experimental conditions and the data analysis used to extract the cross sections.

Luke Myers; John Annand; Jason Brudvik; Gerald Feldman; Kevin Fissum; Harald Grießhammer; Kurt Hansen; Seth Henshaw; Lennart Isaksson; Ramsey Jebali; Michael Kovash; Magnus Lundin; Duncan Middleton; Alan Nathan; Bent Schröder; Sean Stave

2015-03-27

377

Compton Scattering from the Deuteron below Pion-Production Threshold  

E-print Network

Differential cross sections for elastic scattering of photons from the deuteron have recently been measured at the Tagged-Photon Facility at the MAX IV Laboratory in Lund, Sweden. These first new measurements in more than a decade further constrain the isoscalar electromagnetic polarizabilities of the nucleon and provide the first-ever results above 100 MeV, where the sensitivity to the polarizabilities is increased. We add 23 points between 70 and 112 MeV, at angles 60deg, 120deg and 150deg. Analysis of these data using a Chiral Effective Field Theory indicates that the cross sections are both self-consistent and consistent with previous measurements. Extracted values of \\alpha_s = [12.1 +/- 0.8(stat) +/- 0.2(BSR) +/- 0.8(th)] X 10^{-4} fm^3 and \\beta_s = [2.4 +/- 0.8(stat) +/- 0.2(BSR) +/- 0.8(th)] X 10^{-4} fm^3 are obtained from a fit to these 23 new data points. This paper presents in detail the experimental conditions and the data analysis used to extract the cross sections.

Myers, Luke; Brudvik, Jason; Feldman, Gerald; Fissum, Kevin; Grießhammer, Harald; Hansen, Kurt; Henshaw, Seth; Isaksson, Lennart; Jebali, Ramsey; Kovash, Michael; Lundin, Magnus; Middleton, Duncan; Nathan, Alan; Schröder, Bent; Stave, Sean

2015-01-01

378

The proton–deuteron system in pionless EFT revisited  

NASA Astrophysics Data System (ADS)

We provide a detailed discussion of the low-energy proton–deuteron system in pionless effective field theory, considering both the spin-quartet and doublet S-wave channels. Extending and amending our previous work on the subject, we calculate the 3He–3H binding energy difference both perturbatively (using properly normalized trinucleon wave functions) and non-perturbatively by resumming all O(? ) Coulomb diagrams in the doublet channel. Our nonperturbative result agrees well with a calculation that involves the full off-shell Coulomb T-matrix. Carefully examining the cutoff-dependence in the doublet channel, we present numerical evidence for a new three-nucleon counterterm being necessary at next-to-leading order if Coulomb effects are included. Indeed, such a term has recently been identified analytically. We furthermore make a case for a simplified Coulomb power counting that is consistent throughout the bound-state and scattering regimes. Finally, using a ‘partially screened’ full off-shell Coulomb T-matrix, we investigate the importance of higher-order Coulomb corrections in low-energy quartet-channel scattering.

König, Sebastian; Grießhammer, Harald W.; Hammer, H.-W.

2015-04-01

379

Glassy Dynamics of Protein Methyl Groups Revealed by Deuteron NMR  

PubMed Central

We investigated site-specific dynamics of key methyl groups in the hydrophobic core of chicken villin headpiece subdomain (HP36) over the temperature range between 298 and 140K using deuteron solid-state NMR longitudinal relaxation measurements. The relaxation of the longitudinal magnetization is weakly non-exponential (glassy) at high temperatures and exhibits a stronger degree of non-exponentiality below about 175K. In addition, the characteristic relaxation times deviate from the simple Arrhenius law. We interpret this behavior via the existence of distribution of activation energy barriers for the three-site methyl jumps, which originates from somewhat different methyl environments within the local energy landscape. The width of the distribution of the activation barriers for methyl jumps is rather significant, about 1.4 kJ/mol. Our experimental results and modeling allow for the description of the apparent change at about 175K without invoking a specific transition temperature. For most residues in the core, the relaxation behavior at high temperatures points to the existence of conformational exchange between the sub-states of the landscape, and our model takes into account the kinetics of this process. The observed dynamics are the same for dry and hydrated protein. We also looked at the effect of F58L mutation inside the hydrophobic core on the dynamics of one of the residues and observed a significant increase in its conformational exchange rate constant at high temperatures. PMID:23301823

Vugmeyster, Liliya; Ostrovsky, Dmitry; Penland, Kirsten; Hoatson, Gina L.; Vold, Robert L.

2013-01-01

380

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

381

The role of melting in continental breakup and ocean formation  

NASA Astrophysics Data System (ADS)

Active or passive continental rifting is associated with thinning of the lithosphere, ascent of the asthenosphere, and decompressional melting. This melt may percolate within the partially molten source region, accumulate and be extracted. Two-dimensional numerical models of extension of the continental lithosphere-asthenosphere system are carried out using an Eulerian visco-plastic formulation. The equations of conservation of mass, momentum and energy are solved for a multi-component (crust - mantle) and two-phase (solid - melt) system. Temperature-, pressure-, and stress-dependent rheologies based on laboratory data for granite, pyroxenite and olivine are used for the upper and lower crust, and mantle, respectively. Rifting is modelled by externally prescribing a constant rate of widening. A typical extension experiment is characterized by 3 phases: 1) distributed extension, with superimposed pinch and swell instability, 2) lithospheric necking, 3) continental break up, followed by oceanization. The timing of the transition from stage 1) to 2) depends on the presence and magnitude of a localized perturbation, and occurs typically after 100 - 150 km of total extension for the lithospheric system studied here. This necking phase is associated with a pronounced negative topography ("rift valley") and a few 100 m of rift flanks. The dynamic part of this topography amounts to 1 - 2 km positive topography. This means, if rifting stops (e.g. due to a drop of external forces), immediate additional subsidence by this amount is predicted. Melt solidification of ascended melt beneath rift flanks leads to basaltic enrichment and underplating beneath the flanks, often observed at volcanic margins. After continental breakup, a second time-dependent upwelling event off the rift axis beneath the continental margins is found, producing further volcanic volumes. Melting has almost no or only a small accelerating effect on the local extension value (beta-value) for a constant external extension rate. Melting has an extremely strong effect on the upwelling velocity within asthenospheric wedge beneath the new rift. The melt induced sublithospheric convection cell is characterized by downwelling flow beneath rift flanks. Melting increases the topography of the flanks by 100 - 200m due to depletion buoyancy. Another effect of melting is a significant amplification of the central subsidence due to an increase in localized extension/subsidence. Modelled magma amounts are smaller than observed for East African Rift System (EARS). Increasing the mantle temperature, as would be the case active rifting due to a large scale plume head, better fits the observed magma volumes. Interestingly, if the localized perturbation at the central axis is removed, and only a long-wavelength elevated plume head-like temperature anomaly is assumed, a double rift develops. This seems to be a consequence of off-plume axis stress concentrations associated with non-Newtonian rheology. New models including lithospheric weakening due to melt extraction from the asthenosphere and emplacement within the stiff mantle lithosphere will be shown

Schmeling, H.; Wallner, H.

2009-04-01

382

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

NASA Astrophysics Data System (ADS)

To elucidate deformation and breakup processes of a liquid jet across an airstream, tomograms of the liquid jet were taken by means of the laser light sheet method. In this method, fluorescent dye, Eosine-Y, was contained in the injected water, and the liquid jet was illuminated by the Nd:YAG laser light sheet. There are two types of atomization mechanisms. In the first mechanism, a horizontal section of the liquid column is distorted into a bow shape, and there exists a cavity without drops behind the liquid column. Small drops are produced at both tips of the bow. The continuous length and the width of the liquid column were measured from the tomograms. In the second mechanism, in which velocities of both the airstream and the injecting liquid are low, the liquid column is distorted in a snakelike shape and drops are produced near the tip of the liquid column.

Oda, Tetsuya; Hiroyasu, Hiroyuki; Nishida, Keiya

1993-04-01

383

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

SciTech Connect

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

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

2008-07-07

384

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

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

385

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

NASA Astrophysics Data System (ADS)

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

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

2011-03-01

386

Simulation of liquid drop breakup behavior in a flow field using discrete element techniques  

NASA Astrophysics Data System (ADS)

In this study, a discrete element technique was used to simulate drop breakup in two dimensions. A series of simulations in which the drop breakup occurred in the presence of a flow field was performed. The density ratio of the flow field to the drop in the simulations was comparable to many of the isothermal liquid/liquid drop breakup experiments performed to investigate hydrodynamic breakup during Fuel Coolant Interactions (FCI's). The randomly directed internal kinetic energy of the drop increased rapidly at the beginning of the interaction between the drop and the flow field due to momentum transfer from the flow field to the drop. After the initial increase in internal energy of the drop, the momentum transferred from the flow field to the drop in the form of translational kinetic energy of the center of mass of the drop. It was also observed that the drops simulated in the presence of a flow field required higher internal kinetic energies to fragment than did the drops observed in the simulations performed in the absence of a flow field.

Harper, F. T.; Gorham, E. D.; El-Genk, M. S.

387

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

Microsoft Academic Search

In February 2007 dedicated observations were made of the orbital space predicted to contain debris from the breakup of the Titan 3C-4 transtage back on February 21, 1992. These observations were carried out on the Michigan Orbital Debris Survey Telescope (MODEST) in Chile with its 1.3? field of view. The search region or orbital space (inclination and right ascension of

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

2007-01-01

388

Relative Timing of CAMP, Rifting, Continental Breakup, and Basin Inversion: Tectonic Significance  

E-print Network

1 Relative Timing of CAMP, Rifting, Continental Breakup, and Basin Inversion: Tectonic Significance in eastern North America provides a temporal benchmark for assessing the relative timing of rifting, drift, and geochronological data favor a diachronous rift-drift transition (seafloor spreading began earlier in the south

Olsen, Paul E.

389

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

390

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

NASA Technical Reports Server (NTRS)

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

Matney, M. J.; Hamilton, J.; Horstman, M.; Papanyan, V.

2013-01-01

391

ROLE OF CATION DEMIXING AND QUASICRYSTAL FORMATION AND BREAKUP ON THE STABILITY OF SMECTITIC COLLOIDS  

Technology Transfer Automated Retrieval System (TEKTRAN)

The Derjaguin-Landau-Verwey-Overbeek (DLVO) theory has been extensively used to explain colloid stability. This study investigated the effect of demixing of monovalent and divalent cations and crystalline swelling on the breakup and formation of smectite quasicrystals (QCs) and how these processes a...

392

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

Microsoft Academic Search

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

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

1999-01-01

393

The tectonic evolution of the Arctic since Pangea breakup: Integrating constraints from surface geology and geophysics  

E-print Network

and associated deformation. This complexity is expressed in the uncertainty of plate tectonic models models to generate a digital set of tectonic blocks and plates as well as topologically closed plateThe tectonic evolution of the Arctic since Pangea breakup: Integrating constraints from surface

Müller, Dietmar

394

Break-up spots: Could the Pacific open as a consequence of plate kinematics?  

E-print Network

Break-up spots: Could the Pacific open as a consequence of plate kinematics? Valérie Clouard a plate due to intraplate stresses. Present-day intraplate volcanism would define break up spots to break up the lithosphere. This hypothesis was revisited by Sheth Available online at www

Clouard, Valerie

395

Capillary Break-up Rheometry of Low-Viscosity Elastic Fluids  

Microsoft Academic Search

We investigate the dynamics of the capillary thinning and break-up process for low viscosity elastic fluids such as dilute polymer solutions. Standard measurements of the evolution of the midpoint diameter of the necking fluid filament are augmented by high speed digital video images of the break up dynamics. We show that the successful operation of a capillary thinning device is

Lucy E. Rodd; Timothy P. Scott; Justin J. Cooper-White; Gareth H. McKinley

396

Assembly, configuration, and break-up history of Rodinia: A synthesis  

Microsoft Academic Search

This paper presents a brief synthesis of the current state of knowledge on the formation and break-up of the early-Neoproterozoic supercontinent Rodinia, and the subsequent assembly of Gondwanaland. Our discussions are based on both palaeomagnetic constraints and on geological correlations of basement provinces, orogenic histories, sedimentary provenance, the development of continental rifts and passive margins, and the record of mantle

Z. X. Li; S. V. Bogdanova; A. S. Collins; A. Davidson; B. De Waele; R. E. Ernst; I. C. W. Fitzsimons; R. A. Fuck; D. P. Gladkochub; J. Jacobs; K. E. Karlstrom; S. Lu; L. M. Natapov; V. Pease; S. A. Pisarevsky; K. Thrane; V. Vernikovsky

2008-01-01

397

The role of three-dimensional shapes in the break-up of charged drops  

Microsoft Academic Search

The nonlinear dynamics of nonaxisymmetric inviscid charged conducting drops near the Rayleigh charge limit (R = 4) is investigated analytically. It is shown that only axisymmetric spheroid drops bifurcate from the sphere family when the charge is increased, that oblate spheroids at R greater than 4 are unstable to nonaxisymmetric disturbances governing drop breakup, and that prolate spheroids at R

R. Natarajan; R. A. Brown

1987-01-01

398

Large Igneous Provinces, Mantle Plumes, and Continental Break-up: An Overview  

Microsoft Academic Search

Although mantle plumes are widely implicated in models for the generation of large igneous provinces (LIPs) and the break-up of supercontinents such as Gondwana, the exact role of the mantle plume in these processes, and even the very existence of mantle plumes, is controversial and hotly debated. The large volumes of magma produced within a LIP (> 10^6 km^3) in

D. W. Peate

2003-01-01

399

Spatial and temporal perspectives on spring break-up flooding in the Slave River Delta, NWT  

Microsoft Academic Search

Spatial and temporal patterns of spring break-up flooding in the Slave River Delta (SRD), Northwest Territories, are characterized during three years (2003-2005) using water isotope tracers and total inorganic suspended sediment (TSS) concentrations measured from lakewater samples collected shortly after the spring melt. Strongly contrasting spring melt periods led to a moderate flood in 2003, no flooding in 2004 and

B. E. Brock; B. B. Wolfe; T. W. D. Edwards

2008-01-01

400

Molecular dynamics simulation of thread break-up and formation of droplets in nanoejection system  

Microsoft Academic Search

This study investigated nanojet processes by a non-equilibrium molecular dynamics simulation. The phenomena of liquid thread break-up and droplet formation were simulated by compressing liquid propane molecules with various compressing velocities. Properties' distributions show that, at the nanoscale, density and pressure were neither uniform nor continuous during the ejection process. Shear heating phenomena were found in the contact area of

Chi-Fu Dai; Rong-Yeu Chang

2009-01-01

401

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

SciTech Connect

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

Baker, E L; Schwartz, A J

1999-08-11

402

Drop formation and breakup of low viscosity elastic fluids: Effects of molecular weight and concentration  

E-print Network

Drop formation and breakup of low viscosity elastic fluids: Effects of molecular weight of varying concentrations and molecular weights obtained from high speed imaging of the rate of change measurements. The effective relaxation times exhibit the expected scaling with molecular weight

403

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

ERIC Educational Resources Information Center

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

Gilbert, Steven P.; Sifers, Sarah K.

2011-01-01

404

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

E-print Network

Satellites in the inviscid breakup of bubbles J.M. Gordillo Departamento de Ingenier the gas to liquid density ratio = g/l is different from zero, tiny satellite bubbles may be formed with a closed expression for the characteristic satellite diameter, which decreases when decreasing and which

Fontelos, Marco

405

Progress in breakup reaction theory with three charged particles in the final state  

NASA Astrophysics Data System (ADS)

We present a formalism for the elastic Coulomb breakup of a two-body projectile into a three-body final state where all the three entities could be charged, within the framework of the post form distorted wave Born approximation.

Shubhchintak, Chatterjee, R.

2013-04-01

406

JET BREAKUP and SPRAY FORMATION in a DIESEL ENGINE James Glimm  

E-print Network

JET BREAKUP and SPRAY FORMATION in a DIESEL ENGINE James Glimm Department of Applied Mathematics of a fuel eÆcient, nonpollut- ing diesel engine. We report preliminary progress on the numerical simulation Introduction The design of a fuel eÆcient, nonpolluting diesel engine is the subject of intensive international

New York at Stoney Brook, State University of

407

Breakup and conditions for stability of the northern Larsen Ice Shelf, Antarctica  

Microsoft Academic Search

The breakup of ice shelves has been widely regarded as an indicator of climate change, with observations around the Antarctic Peninsula having shown a pattern of gradual retreat, associated with regional atmospheric warming and increased summer melt and fracturing processes. The rapid collapse of the northernmost section of the Larsen Ice Shelf (Larsen A), over a few days in January

C. S. M. Doake; H. F. J. Corr; H. Rott; P. Skvarca; N. W. Young

1998-01-01

408

Beam-breakup instability theory for energy recovery linacs Georg H. Hoffstaetter and Ivan V. Bazarov  

E-print Network

Beam-breakup instability theory for energy recovery linacs Georg H. Hoffstaetter and Ivan V during each recirculation turn. This is important for the description of energy recovery linacs where.054401 PACS numbers: 29.27.Bd I. INTRODUCTION Synchrotron light sources based on energy recovery linacs (ERLs

Hoffstaetter, Georg

409

CAPITALIZATION OF THE BREAK-UP OF LAUSD INTO 11 SUB-DISTRICTS  

Microsoft Academic Search

ABSTRACT This study investigates the ,effects of the breakup ,of the ,Los Angeles Unified School District (LAUSD) on housing prices. Under increasing pressureof falling test scores and high drop out rates, the School Board of the LAUSD unanimously voted to break up the district into 11 mini-districts in April 2000. Theoretically, this should increase school choice and school quality, which

Garima Bhalla

2006-01-01

410

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

E-print Network

.............................................................. The recent breakup of an asteroid ............................................................................................................................................................................. The present population of asteroids in the main belt is largely the result of many past collisions1,2 . Ideally, the asteroid fragments resulting from each impact event could help us understand the large

Nesvorny, David

411

Application of the complex scaling method for few-body scattering problems including the breakup  

NASA Astrophysics Data System (ADS)

A formalism based on the complex-scaling method is used to solve a few-particle scattering problem in configuration space. This method allows to use trivial boundary conditions and is compatible with most of the bound state techniques. In this contribution calculations of neutron scattering on triton is presented using realistic nuclear Hamiltonians for neutron energies above four-nucleon breakup threshold.

Lazauskas, Rimantas

2014-12-01

412

Deformation and breakup of Newtonian and non-Newtonian conducting drops in an electric field  

Microsoft Academic Search

In this article, we considered experimentally the deformation and breakup of Newtonian and non-Newtonian conducting drops in surrounding fluid subjected to a uniform electric field. First, we examined three distinctive cases of Newtonian-fluid pairs with different relative conductivities, namely highly conducting drops, conducting drops and slightly conducting drops. The results on the Newtonian fluids demonstrated that when the conductivity of

Jong-Wook Ha; Seung-Man Yang

2000-01-01

413

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

NASA Astrophysics Data System (ADS)

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

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

2013-12-01

414

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

NASA Technical Reports Server (NTRS)

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

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

2012-01-01

415

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

PubMed

The purpose of this research was to examine the associations of attachment anxiety and avoidance with personal growth following relationship dissolution, and to test breakup distress, rumination, and tendency to rebound with new partners as mediators of these associations. Study 1 (N = 411) and Study 2 (N = 465) measured attachment style, breakup distress, and personal growth; Study 2 additionally measured ruminative reflection, brooding, and proclivity to rebound with new partners. Structural equation modelling revealed in both studies that anxiety was indirectly associated with greater personal growth through heightened breakup distress, whereas avoidance was indirectly associated with lower personal growth through inhibited breakup distress. Study 2 further showed that the positive association of breakup distress with personal growth was accounted for by enhanced reflection and brooding, and that anxious individuals' greater personal growth was also explained by their proclivity to rebound. These findings suggest that anxious individuals' hyperactivated breakup distress may act as a catalyst for personal growth by promoting the cognitive processing of breakup-related thoughts and emotions, whereas avoidant individuals' deactivated distress may inhibit personal growth by suppressing this cognitive work. PMID:24066169

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

2013-01-01

416

Attachment Styles and Personal Growth following Romantic Breakups: The Mediating Roles of Distress, Rumination, and Tendency to Rebound  

PubMed Central

The purpose of this research was to examine the associations of attachment anxiety and avoidance with personal growth following relationship dissolution, and to test breakup distress, rumination, and tendency to rebound with new partners as mediators of these associations. Study 1 (N?=?411) and Study 2 (N?=?465) measured attachment style, breakup distress, and personal growth; Study 2 additionally measured ruminative reflection, brooding, and proclivity to rebound with new partners. Structural equation modelling revealed in both studies that anxiety was indirectly associated with greater personal growth through heightened breakup distress, whereas avoidance was indirectly associated with lower personal growth through inhibited breakup distress. Study 2 further showed that the positive association of breakup distress with personal growth was accounted for by enhanced reflection and brooding, and that anxious individuals’ greater personal growth was also explained by their proclivity to rebound. These findings suggest that anxious individuals’ hyperactivated breakup distress may act as a catalyst for personal growth by promoting the cognitive processing of breakup-related thoughts and emotions, whereas avoidant individuals’ deactivated distress may inhibit personal growth by suppressing this cognitive work. PMID:24066169

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

2013-01-01

417

Status of the investigation of the spin structure of d, {sup 3}H, and {sup 3}He at VBLHE using polarized and unpolarized deuteron beam  

SciTech Connect

The investigation of the spin structure of d, {sup 3}H, and {sup 3}He has been performed at the RIKEN acceleration research facility and VBLHE. Vector A{sub y} and tensor A{sub yy}, A{sub xx}, A{sub xz} analyzing powers for d-bar-vector d {yields} {sup 3}Hen and d-bar-vector d {yields} {sup 3}Hp are presented at 270 MeV. The mirror channels ({sup 3}Hen and {sup 3}Hp) are compared to each other in order to find possible manifestation of charge-symmetry breaking. The preliminary results on the polarization observables for d-bar-vector d {yields} {sup 3}Hp at 200MeV are also presented. The obtained data are compared with one-nucleon-exchange calculations. As a byproduct, d-bar-vector d {yields} pX and d-bar-vector {yields} {sup 12}C {yields} pX breakup reactions are investigated at 140, 200, and 270MeV. The experimental data on d-bar-vector p elastic scattering were obtained at 270, 880, and 2000 MeV at the Nuclotron. The polarization of the deuteron beam was measured at 270 MeV at the internal target station. The preliminary data on the vector A{sub y} and tensor A{sub yy}, A{sub xx} analyzing powers for the d-bar-vector p elastic scattering at 880 MeV are presented. The calculations on A{sub y}, A{sub yy}, and A{sub xx} analyzing powers for the d-bar-vector p elastic scattering at 880 MeV were performed in the framework of the multiple-scattering model.

Janek, M., E-mail: janek@sunhe.jinr.ru; Ladygin, V. P., E-mail: ladygin@sunhe.jinr.ru; Azhgirey, L. S. [Joint Institute for Nuclear Research (Russian Federation); Uesaka, T. [University of Tokyo, Center for Nuclear Study (Japan); Gurchin, Yu. V. [Joint Institute for Nuclear Research (Russian Federation); Hatano, M. [University of Tokyo, Department of Physics (Japan); Itoh, K. [Saitama University, Department of Physics (Japan); Isupov, A. Yu.; Karachuk, J.-T. [Joint Institute for Nuclear Research (Russian Federation); Kato, H. [University of Tokyo, Department of Physics (Japan); Kawabata, T. [University of Tokyo, Center for Nuclear Study (Japan); Krasnov, V. A.; Khrenov, A. N.; Kiselev, A. S.; Kizka, V. A.; Kliman, J.; Kurilkin, A. K.; Kurilkin, P. K.; Ladygina, N. B.; Livanov, A. N. [Joint Institute for Nuclear Research (Russian Federation)

2008-09-15

418

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

SciTech Connect

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

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

2013-05-13

419

Precursor Experiments to Search for Permanent Electric Dipole Moments (EDMs) of Protons and Deuterons at COSY  

E-print Network

In this presentation we discuss a number of experiments on the search for proton or deuteron EDMs, which could be carried out at COSY-Juelich. Most promising is the use of an radio-frequency radial electric field flipper that would lead to the accumulation of a CP violating in-plane beam polarization by tiny spin rotations. Most crucial for storage ring searches for EDMs is the spin-coherence time, and we report on analytic evaluations which point at a much larger spin-coherence time for deuterons by about a factor of 200 compared to the one for protons, and at COSY, the spin coherence time for deuterons could amount to about 10 000 s.

Andreas Lehrach; Bernd Lorentz; William Morse; Nikolai Nikolaev; Frank Rathmann

2012-01-27

420

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

NASA Astrophysics Data System (ADS)

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

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

2013-05-01

421

Empirical fit to inelastic electron-deuteron and electron-neutron resonance region transverse cross sections  

SciTech Connect

An empirical fit is described to measurements of inclusive inelastic electron-deuteron cross sections in the kinematic range of four-momentum transfer 0{<=}Q{sup 2}<10 GeV{sup 2} and final state invariant mass 1.1deuteron fit relies on a fit of the ratio R{sub p} of longitudinal to transverse cross sections for the proton, and the assumption R{sub p}=R{sub n}. The underlying fit parameters describe the average cross section for a free proton and a free neutron, with a plane-wave impulse approximation used to fit to the deuteron data. Additional fit parameters are used to fill in the dip between the quasi-elastic peak and the {delta}(1232) resonance. The mean deviation of data from the fit is 3%, with less than 4% of the data points deviating from the fit by more than 10%.

Bosted, P. E. [Jefferson Laboratory, Newport News, Virginia 23606 (United States); Christy, M. E. [Hampton University, Hampton, Virginia 23668 (United States)

2008-06-15

422

New fits to inclusive electron scattering from proton, neutron, and deuteron at low Q$^2$  

SciTech Connect

An empirical fit is described to measurements of inclusive inelastic electron-proton and electron-deuteron cross sections in the kinematic range $0 \\le Q^2<8$ GeV$^2$ and $1.1deuteron fit relies on a fit of the ratio $R_p=\\sigma_L/\\sigma_T$ for the proton, and the assumption $R_p=R_n$. The underlying fit parameters describe the average cross section for a free proton and a free neutron, with a plane-wave impulse approximation used to fit to the deuteron data. The mean deviation of data from the fits is 3\\%, with less than 4\\% of the data points deviating from the fit by more than 10\\%. As an example of the usefulness of the fit, the extended Baldin sum is evaluated to $Q^2=0.3$ GeV$^2$.

Bosted, Peter; Christy, Michael

2008-07-01

423

Empirical Fit to Inelastic Electron-Deuteron and Electron-Neutron Resonance Region Transverse Cross Sections  

SciTech Connect

An empirical fit is described to measurements of inclusive inelastic electron-deuteron cross sections in the kinematic range of four-momentum transfer $0 \\le Q^2<10$ GeV$^2$ and final state invariant mass $1.2<3$ GeV. The deuteron fit relies on a fit of the ratio $R_p$ of longitudinal to transverse cross sections for the proton, and the assumption $R_p=R_n$. The underlying fit parameters describe the average cross section for proton and neutron, with a plane-wave impulse approximation (PWIA) used to fit to the deuteron data. Pseudo-data from MAID 2007 were used to constrain the average nucleon cross sections for $W<1.2$ GeV. The mean deviation of data from the fit is 3\\%, with less than 5\\% of the data points deviating from the fit by more than 10\\%.

Peter Bosted; M. E. Christy

2007-11-08

424

Observation of neutron spectrum produced by fast deuterons via ultraintense laser plasma interactions.  

PubMed

We report the first precise spectral measurement of fast neutrons produced in a deuterated plastic target irradiated by an ultraintense sub-picosecond laser pulse. The 500-fs, 50-J, 1054-nm laser pulse was focused on the deuterated polystyrene target with an intensity of 2 x 10(19) W/cm(2). The neutron spectra were observed at 55 degrees and 90 degrees to the rear target normal. The neutron emission was 7 x 10(4) per steradian for each detector. The observed neutron spectra prove the acceleration of deuterons and neutron production by d(d,n)3He reactions in the target. The neutron spectra were compared with Monte Carlo simulation results and the deuteron's directional anisotropy and energy spectrum were studied. We conclude that 2% of the laser energy was converted to deuterons, which has an energy range of 30 keV up to 3 MeV. PMID:11909268

Izumi, N; Sentoku, Y; Habara, H; Takahashi, K; Ohtani, F; Sonomoto, T; Kodama, R; Norimatsu, T; Fujita, H; Kitagawa, Y; Mima, K; Tanaka, K A; Yamanaka, T

2002-03-01

425

Study of the Two-pion Photoproduction on the Deuteron  

SciTech Connect

Understanding the structure of baryons in terms of the fundamental interaction of the constituent quarks and gluons is one of the primary challenges in strong interaction physics. This interaction is governed by Quantum Chromodynamics (QCD), which is a theory for understanding the dynamics of strong. QCD displays the asymptotic freedom of hadrons at very short distances and also the confinement of quarks and gluons inside hadrons. However, solutions of this QCD theory in the non-perturbative domain of the interaction are extremely difficult to achieve, mainly because confinement happens on the hadronic scale on which the coupling constant is large and prevents any perturbative approach. Thus leaving us with strategies such as lattice QCD or formulating QCD sum rules to get around this problem. In exclusive hadron production the yN interaction is recognized for being a powerful method for investigating hadrons and the mysteries that still exist within the strong interaction. From reactions with the nucleon, the strong interaction can be investigated through the transition amplitudes to the N and Delta resonances. More specifically, if an electromagnetic interaction is well known then the intermediate resonance states may be evaluated through meson photoproduction. To gain more detailed insight into this interaction, we look to probe the baryon structure of the nucleon and the photo-excited resonance decays through photon scattering off a deuteron producing two pions in the final state. This photoproduction process off the deuteron will be used to investigate known baryon resonances in the two pion channel. The two pion final state will be investigated for unraveling new information into the photo-coupling strengths. We want to explore final state interactions, search for properties of known resonances, and to explore the possibility of seeing missing states that are predicted by quark models but have not yet been found experimentally. Using the CEBAF Large Acceptance Spectrometer (CLAS), the hadronic products are detected in coincidence with the incident scattered photon on a deuterium target. This makes it possible to measure the single differential cross sections and the decay angular distributions for the production of two pion final states. The measured cross sections will contribute significantly to a better understanding of the coupling strengths that govern the baryonic and mesonic resonances which will push the knowledge of the strong interaction to a next level. We use CLAS to study the two pion channel from the eg3 data set, for resonance production, specifically investigating the exclusive reaction of yd --> p pi^+pi^?n, and comparing the relevant cross sections to already existing data sets. The eg3 data set provided an excellent data set for investigating photo-induced baryonic and mesonic resonances. It contains a large photon tagging range from 1.1 to 5.5 GeV in the study of photo-coupling strengths, as well as an available two pion reaction channel for resonant decay study. These measurements provide unique and coherent results from tagged photons over a broad range of energy, and represent the only two pion production data above 5 GeV at this present time. We found that the data produced good comparable single-differentials cross sections to other existing CLAS (gll dataset) two pion differential cross sections, and an excellent comparable total cross section to published (ELSA and ABBHHM) two pion total cross sections.

Graham, Lewis P. [South Carolina U.

2012-12-01

426

Elastic Nd scattering at intermediate energies as a tool for probing the short-range deuteron structure  

SciTech Connect

A calculation of the deuteron polarization observables A{sub y}{sup d}, A{sub yy}, A{sub xx}, A{sub xz} and the differential cross section for elastic nucleon-deuteron scattering at incident deuteron energies 270 and 880 MeV in lab is presented. A comparison of the calculations with two different deuteron wave functions derived from the Bonn-CD NN-potential model and the dressed-quark-bag model is carried out. A model-independent approach, based on an optical-potential framework, is used in which a nucleon-nucleon T matrix is assumed to be local and taken on the energy shell, but still depends on the internal nucleon momentum in a deuteron.

Shikhalev, M. A., E-mail: shikhalev@jinr.r [Joint Institute for Nuclear Research (Russian Federation)

2009-04-15

427

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

428

Deuteron Magnetic Resonance in Amorphous Silicon and Germanium.  

NASA Astrophysics Data System (ADS)

Plasma-deposited thin films of a -Si(H,D) and a-Ge(H,D) have been characterized by deuteron magnetic resonance. Measurements of spin-lattice relaxation times and line shapes were made between 2 and 320 K to determine the structural role played by hydrogen and deuterium in these samples. Deuterium in Si-D and Ge-D bonded configurations exhibited Pake doublets with temperature independent splittings of 66 kHz and 60 kHz respectively. A broad central component with a temperature independent 34 kHz line width was identified as arising from matrix isolated D_2 and HD molecules. Multiple spin echoes from the HD molecules in these configurations were observed and their widths, amplitudes and time of occurrence were found to be related to their intramolecular dipole and quadrupole coupling strengths. Existence of the multiple echoes down to 4 K indicated significant admixtures of higher rotational J states into the J = 0 ground state caused by large crystalline field gradients arising from the silicon environment. A narrow central component whose line width varied from 300 Hz at 300 K to 5 kHz at 2 K was also observed. This component arose from D_2 and HD molecules contained in sample voids and the change in line width was due to the motional averaging of electric field gradients seen by the molecules. Spin-lattice relaxation was dominated by restricted spin diffusion of net magnetization to p -D_2 and HD relaxation centers. Below 40 K a 76 kHz doublet appeared from frozen out p -D_2 molecules whose transition rates amongst m_{rm J} sublevels was less than their intramolecular coupling frequency.

Volz, Martin Paul

429

Comparative analysis of properties of channels of deuteron and tritium production in {sup 16}Op collisions at a projectile momentum of 3.25 GeV/c per nucleon  

SciTech Connect

The results of a comparative analysis of channels involving the inclusive production of deuterons and tritons in {sup 16}Op collisions at a projectile momentum of 3.25 GeV/c per nucleon are presented. The mechanisms governing proton, deuteron, and triton production in the fragmentation of oxygen nuclei are found to be independent. It is shown that the observed proton-multiplicity correlations are associated predominantly with the character of the primary event of a proton-nucleon collision in {sup 16}Op interactions. It is found that, in reactions involving triton production, the contributions of processes leading to an increase in the mean proton multiplicity (n ? p + ?{sup ?} and np ? pn) and processes leading to its decrease (p ? n + ?{sup +}) compensate each other.

Olimov, K., E-mail: olimov@uzsci.net [Uzbek Academy of Sciences, Physical Technical Institute, Scientific Production Association Physics-Sun (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, Physical Technical Institute, Scientific Production Association Physics-Sun (Uzbekistan)

2014-12-15

430

Comparative analysis of properties of channels of deuteron and tritium production in 16O p collisions at a projectile momentum of 3.25 GeV/ c per nucleon  

NASA Astrophysics Data System (ADS)

The results of a comparative analysis of channels involving the inclusive production of deuterons and tritons in 16O p collisions at a projectile momentum of 3.25 GeV/ c per nucleon are presented. The mechanisms governing proton, deuteron, and triton production in the fragmentation of oxygen nuclei are found to be independent. It is shown that the observed proton-multiplicity correlations are associated predominantly with the character of the primary event of a proton-nucleon collision in 16O p interactions. It is found that, in reactions involving triton production, the contributions of processes leading to an increase in the mean proton multiplicity ( n ? p + ? - and np ? pn) and processes leading to its decrease ( p ? n + ? +) compensate each other.

Olimov, K.; Glagolev, V. V.; Gulamov, K. G.; Kurbanov, A.; Lutpullaev, S. L.; Olimov, A. K.; Petrov, V. I.; Yuldashev, A. A.

2014-12-01

431

Polarization observables in elastic electron deuteron scattering including parity and time reversal violating contributions  

E-print Network

The general formalism for polarization observables in elastic electron deuteron scattering is extended to incorporate parity and time reversal violating contributions. Parity violating effects arise from the interference of $\\gamma$ and $Z$ exchange as well as from the hadronic sector via a small parity violating component in the deuteron. In addition we have allowed for time reversal invariance violating contributions in the hadronic sector. Formal expressions for the additional structure functions are derived, and their decomposition into the various multipole contributions are given explicitly.

Hartmuth Arenhoevel; Shri K. Singh

2000-12-19

432

The proton and deuteron F_2 structure function at low Q^2  

E-print Network

Measurements of the proton and deuteron $F_2$ structure functions are presented. The data, taken at Jefferson Lab Hall C, span the four-momentum transfer range $0.06 structure function is in good agreement with a parameterization of $F_2$ based on data that have been taken at much higher values of $Q^2$ or much lower values of $x$, and which is constrained by data at the photon point. The ratio of the deuteron and proton structure functions at low $x$ remains well described by a logarithmic dependence on $Q^2$ at low $Q^2$.

V. Tvaskis; J. Arrington; R. Asaturyan; O. K. Baker; H. P. Blok; P. Bosted; M. Boswell; A. Bruell; M. E. Christy; A. Cochran; R. Ent; B. W. Filippone; A. Gasparian; C. E. Keppel; E. Kinney; L. Lapikás; W. Lorenzon; D. J. Mack; J. Mammei; J. W. Martin; H. Mkrtchyan; I. Niculescu; R. B. Piercey; D. H. Potterveld; G. Smith; K. Spurlock; G. van der Steenhoven; S. Stepanyan; V. Tadevosian; S. A. Wood

2010-02-08

433

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

SciTech Connect

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

Lin, F.; Malitsky, N. D.; Luccio, A. U.; Morse, W. M.; Semertzidis, Y. K. [Brookhaven National Laboratory, Upton, NY (United States); Onderwater, C. J. G. [University of Groningen, NL-9747AA Groningen (Netherlands); Orlov, Y. F. [Cornell University, Ithaca, NY (United States)

2009-08-04

434

Gerasimov-Drell-Hearn and Burkhardt-Cottingham Sum Rules for Proton, Neutron and Deuteron  

E-print Network

A description of the generalized Gerasimov-Drell-Hearn sum rules for proton, neutron and deuteron is suggested. The proton consideration confirms the earlier conjecture, that the structure function $g_T$ features a smooth $Q^2-$dependence, while the structure function $g_2$ is changing rapidly, due to the elastic contribution to the Burkhardt-Cottingham sum rule. The neutron case features the close connection to the Bjorken sum rule. The deuteron case reveals the crucial role of photodesintegration channel, resulting in the strong nuclear correction at very low $Q^2$. The new approximate sum rules for this channel reflecting the delicate interplay between nucleon and nuclear structure are suggested.

O. V. Teryaev

2003-03-05

435

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

NASA Astrophysics Data System (ADS)

The first observation of (anti)deuterons in deep inelastic scattering at HERA has been made with the ZEUS detector at a centre-of-mass energy of 300-318 GeV using an integrated luminosity of 120 pb -1. The measurement was performed in the central rapidity region for transverse momentum per unit of mass in the range 0.3

deuteron production yield is smaller than the (anti)proton yield by approximately three orders of magnitude, consistent with the world measurements.

Chekanov, S.; Derrick, M.; Magill, S.; Musgrave, B.; Nicholass, D.; Repond, J.; Yoshida, R.; Mattingly, M. C. K.; Jechow, M.; Pavel, N.; Yagües Molina, A. G.; Antonelli, S.; Antonioli, P.; Bari, G.; Basile, M.; Bellagamba, L.; Bindi, M.; Boscherini, D.; Bruni, A.; Bruni, G.; Cifarelli, L.; Cindolo, F.; Contin, A.; Corradi, M.; De Pasquale, S.; Iacobucci, G.; Margotti, A.; Nania, R.; Polini, A.; Sartorelli, G.; Zichichi, A.; Bartsch, D.; Brock, I.; Goers, S.; Hartmann, H.; Hilger, E.; Jakob, H.-P.; Jüngst, M.; Kind, O. M.; Nuncio-Quiroz, A. E.; Paul, E.; Renner, R.; Samson, U.; Schönberg, V.; Shehzadi, R.; Wlasenko, M.; Brook, N. H.; Heath, G. P.; Morris, J. D.; Namsoo, T.; Capua, M.; Fazio, S.; Mastroberardino, A.; Schioppa, M.; Susinno, G.; Tassi, E.; Kim, J. Y.; Ma, K. J.; Ibrahim, Z. A.; Kamaluddin, B.; Wan Abdullah, W. A. T.; Ning, Y.; Ren, Z.; Sciulli, F.; Chwastowski, J.; Eskreys, A.; Figiel, J.; Galas, A.; Gil, M.; Olkiewicz, K.; Stopa, P.; Zawiejski, L.; Adamczyk, L.; Bo?d, T.; Grabowska-Bo?d, I.; Kisielewska, D.; ?ukasik, J.; Przybycie?, M.; Suszycki, L.; Kota?ski, A.; S?omi?ski, W.; Adler, V.; Behrens, U.; Bloch, I.; Blohm, C.; Bonato, A.; Borras, K.; Ciesielski, R.; Coppola, N.; Dossanov, A.; Drugakov, V.; Fourletova, J.; Geiser, A.; Gladkov, D.; Göttlicher, P.; Grebenyuk, J.; Gregor, I.; Haas, T.; Hain, W.; Horn, C.; Hüttmann, A.; Kahle, B.; Katkov, I. I.; Klein, U.; Kötz, U.; Kowalski, H.; Lobodzinska, E.; Löhr, B.; Mankel, R.; Melzer-Pellmann, I.-A.; Miglioranzi, S.; Montanari, A.; Notz, D.; Rinaldi, L.; Roloff, P.; Rubinsky, I.; Santamarta, R.; Schneekloth, U.; Spiridonov, A.; Stadie, H.; Szuba, D.; Szuba, J.; Theedt, T.; Wolf, G.; Wrona, K.; Youngman, C.; Zeuner, W.; Lohmann, W.; Schlenstedt, S.; Barbagli, G.; Gallo, E.; Pelfer, P. G.; Bamberger, A.; Dobur, D.; Karstens, F.; Vlasov, N. N.; Bussey, P. J.; Doyle, A. T.; Dunne, W.; Ferrando, J.; Forrest, M.; Saxon, D. H.; Skillicorn, I. O.; Gialas, I.; Papageorgiu, K.; Gosau, T.; Holm, U.; Klanner, R.; Lohrmann, E.; Salehi, H.; Schleper, P.; Schörner-Sadenius, T.; Sztuk, J.; Wichmann, K.; Wick, K.; Foudas, C.; Fry, C.; Long, K. R.; Tapper, A. D.; Kataoka, M.; Matsumoto, T.; Nagano, K.; Tokushuku, K.; Yamada, S.; Yamazaki, Y.; Barakbaev, A. N.; Boos, E. G.; Pokrovskiy, N. S.; Zhautykov, B. O.; Aushev, V.; Son, D.; de Favereau, J.; Piotrzkowski, K.; Barreiro, F.; Glasman, C.; Jimenez, M.; Labarga, L.; del Peso, J.; Ron, E.; Soares, M.; Terrón, J.; Zambrana, M.; Corriveau, F.; Liu, C.; Walsh, R.; Zhou, C.; Tsurugai, T.; Antonov, A.; Dolgoshein, B. A.; Sosnovtsev, V.; Stifutkin, A.; Suchkov, S.; Dementiev, R. K.; Ermolov, P. F.; Gladilin, L. K.; Khein, L. A.; Korzhavina, I. A.; Kuzmin, V. A.; Levchenko, B. B.; Lukina, O. Yu.; Proskuryakov, A. S.; Shcheglova, L. M.; Zotkin, D. S.; Zotkin, S. A.; Abt, I.; Büttner, C.; Caldwell, A.; Kollar, D.; Schmidke, W. B.; Sutiak, J.; Grigorescu, G.; Keramidas, A.; Koffeman, E.; Kooijman, P.; Pellegrino, A.; Tiecke, H.; Vázquez, M.; Wiggers, L.; Brümmer, N.; Bylsma, B.; Durkin, L. S.; Lee, A.; Ling, T. Y.; Allfrey, P. D.; Bell, M. A.; Cooper-Sarkar, A. M.; Cottrell, A.; Devenish, R. C. E.; Foster, B.; Korcsak-Gorzo, K.; Patel, S.; Roberfroid, V.; Robertson, A.; Straub, P. B.; Uribe-Estrada, C.; Walczak, R.; Bellan, P.; Bertolin, A.; Brugnera, R.; Carlin, R.; Dal Corso, F.; Dusini, S.; Garfagnini, A.; Limentani, S.; Longhin, A.; Stanco, L.; Turcato, M.; Oh, B. Y.; Raval, A.; Ukleja, J.; Whitmore, J. J.; Iga, Y.; D'Agostini, G.; Marini, G.; Nigro, A.; Cole, J. E.; Hart, J. C.; Abramowicz, H.; Gabareen, A.; Ingbir, R.; Kananov, S.; Levy, A.; Kuze, M.; Maeda, J.; Hori, R.; Kagawa, S.; Okazaki, N.; Shimizu, S.; Tawara, T.; Hamatsu, R.; Kaji, H.; Kitamura, S.; Ota, O.; Ri, Y. D.; Ferrero, M. I.; Monaco, V.; Sacchi, R.; Solano, A.; Arneodo, M.; Ruspa, M.; Fourletov, S.; Martin, J. F.; Boutle, S. K.; Butterworth, J. M.; Gwenlan, C.; Jones, T. W.; Loizides, J. H.; Sutton, M. R.; Wing, M.; Brzozowska, B.; Ciborowski, J.; Grzelak, G.; Kulinski, P.; ?u?niak, P.; Malka, J.; Nowak, R. J.; Pawlak, J. M.; Tymieniecka, T.; Ukleja, A.; ?arnecki, A. F.; Adamus, M.; Plucinski, P.; Eisenberg, Y.; Giller, I.; Hochman, D.; Karshon, U.; Rosin, M.; Brownson, E.; Danielson, T.; Everett, A.; Kçira, D.; Reeder, D. D.; Ryan, P.; Savin, A. A.; Smith, W. H.; Wolfe, H.; Bhadra, S.; Catterall, C. D.; Cui, Y.; Hartner, G.; Menary, S.; Noor, U.; Standage, J.; Whyte, J.; ZEUS Collaboration

2007-12-01

436

Excitation of Giant Monopole Resonance in $^{208}$Pb and $^{116}$Sn Using Inelastic Deuteron Scattering  

E-print Network

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

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

2014-06-26

437

Importance of the Doppler Effect to the Determination of the Deuteron Binding Energy  

E-print Network

The deuteron binding energy extracted from the reaction ${}^1H(n,\\gamma){}^2H$ is reviewed with the exact relativistic formula, where the initial kinetic energy and the Doppler effect are taken into account. We find that the negligible initial kinetic energy of the neutron could cause a significant uncertainty which is beyond the errors available up to now. Therefore, we suggest an experiment which should include the detailed informations about the initial kinetic energy and the detection angle. It could reduce discrepancies among the recently reported values about the deuteron binding energy and pin down the uncertainty due to the Doppler broadening of $\\gamma$ ray.

Yongkyu Ko; Myung Ki Cheoun; Il-Tong Cheon

1999-04-01

438

Effect of the break-up on the fusion and elastic scattering of weakly bound projectiles on $^{64}$Zn  

E-print Network

We study the behavior of the fusion, break-up, reaction and elastic scattering of different projectiles on $^{64}$Zn, at near and above barrier energies. We present fusion and elastic scattering data with the tightly bound $^{16}$O and the stable weakly bound $^{6}$Li, $^{7}$Li and $^{9}$Be projectiles. The data were analyzed by coupled channel calculations. The total fusion cross sections for these systems are not affected by the break-up process at energies above the barrier. The elastic (non-capture) break-up cross section is important at energies close and above the Coulomb barrier and increases the reaction cross sections. In addition we also show that the break-up process at near and sub-barrier energies is responsible for the vanishing of the usual threshold anomaly of the optical potential and give rise to a new type of anomaly.

P. R. S. Gomes; M. D. Rodriguez; C. V. Marti; I. Padron; L. C. Chamon; J. O. Fernandez Niello; O. A. Capurro; A. J. Pacheco; J. E. Testoni; A. Arazi; M. Ramirez; R. M. Anjos; J. Lubian; R. Viega; R. Liguori Neto; E. Crema; N. Added; C. Tenreiro; M. S. Hussein

2005-02-01

439

High Throughput Synthesis of Uniform Biocompatible Polymer Beads with High Quantum Dot Loading Using Microfluidic Jet-Mode Breakup  

E-print Network

Uniform polymer microbeads with highly loaded quantum dots (QDs) are produced using high-throughput coherent jet breakup of a biocompatible poly(ethylene glycol) diacrylate (PEGDA) prepolymer resin, followed by in-line ...

Lee, Seung-Kon

440

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

NASA Astrophysics Data System (ADS)

Coulomb breakup of unstable neutron rich nuclei 29,30Na around the `island of inversion' has been studied at energy around 434 MeV/nucleon and 409 MeV/nucleon respectively. Four momentum vectors of fragments, decay neutron from excited projectile and ?-rays emitted from excited fragments after Coulomb breakup are measured in coincidence. For these nuclei, the low-lying dipole strength above one neutron threshold can be explained by direct breakup model. The analysis for Coulomb breakup of 29,30Na shows that large amount of the cross section yields the 28Na, 29Na core in ground state. The predominant ground-state configuration of 29,30Na is found to be 28Na(g.s)??s1/2 and 29Na(g.s)??s1/2,respectively.

Rahaman, A.; Datta Pramanik, U.; Aumann, T.; Beceiro, S.; Boretzky, K.; Caesar, C.; Carlson, B. V.; Catford, W. N.; Chakraborty, S.; Chatterjee, S.; Chartier, M.; De Angelis, G.; Cortina-Gil, D.; Gonzalez-Diaz, D.; Emling, H.; Diaz Fernandez, P.; Fraile, L. M.; Ershova, O.; Geissel, H.; Heil, M.; Jonson, B.; Kelic, A.; Johansson, H.; Kruecken, R.; Kroll, T.; Kurcewicz, J.; Langer, C.; Bleis, T. Le; Leifels, Y.; Munzenberg, G.; Marganiec, J.; Nociforo, C.; Najafi, A.; Panin, V.; Paschalis, S.; Pietri, S.; Plag, R.; Reifarth, R.; Ricciardi, V.; Rossi, D.; Ray, J.; Simon, H.; Scheidenberge, C.; Typel, S.; Taylor, J.; Togano, Y.; Volkov, V.; Weick, H.; Wagner, A.; Wamers, F.; Weigand, M.; Winfield, J. S.; Yakorev, D.; Zoric, M.

2014-03-01

441

Near-threshold deuteron photodisintegration: An indirect determination of the Gerasimov-Drell-Hearn sum rule and forward spin polarizability (?0) for the deuteron at low energies  

NASA Astrophysics Data System (ADS)

It is shown that a measurement of the analyzing power obtained with linearly polarized ?-rays and an unpolarized target can provide an indirect determination of two physical quantities. These are the Gerasimov-Drell-Hearn (GDH) sum rule integrand for the deuteron and the sum rule integrand for the forward spin polarizability (?0) near photodisintegration threshold. An analysis of data for the d(??,n)p reaction and other experiments is presented. A fit to the world data analyzed in this manner gives a GDH integral value of -603±43?b between the photodisintegration threshold and 6 MeV. This result is the first confirmation of the large contribution of the 1S0(M1) transition predicted for the deuteron near photodisintegration threshold. In addition, a sum rule value of 3.75±0.18 fm4 for ?0 is obtained between photodisintegration threshold and 6 MeV. This is a first indirect confirmation of the leading-order effective field theory prediction for the forward spin-polarizability of the deuteron.

Ahmed, M. W.; Blackston, M. A.; Perdue, B. A.; Tornow, W.; Weller, H. R.; Norum, B.; Sawatzky, B.; Prior, R. M.; Spraker, M. C.

2008-04-01

442

Drift and breakup of spiral waves in reaction-diffusion-mechanics systems. A.V. Panfilov  

E-print Network

a variety of important phenomena, such as cardiac arrhythmias, morphogenesis processes and spatial patterns examples of spiral waves include: spiral waves during morphogenesis of the Dic- tyostelium discoideum during Dictyostelium discoideum morphogenesis are relayed by chemotactically moving cells [4]; and chemi

Utrecht, Universiteit

443

Catastrophic ice-shelf break-up by an ice-shelf-fragment-capsize mechanism  

Microsoft Academic Search

Two disintegration events leading to the loss of Larsen A and B ice shelves, Antarctic Peninsula, in 1995 and 2002, respectively,proceeded with extreme rapidity (order of several days) and reduced an extensive, seemingly integrated ice shelf to a jumble of small fragments. These events strongly correlate with warming regional climate and accumulation of surface meltwater, supporting a hypothesis that meltwater-induced

Douglas R. Macayeal; Ted A. Scambos; Christina L. Hulbe; Mark A. Fahnestock

2003-01-01

444

Recent Retreat of Wilkins Ice Shelf Reveals New Insights in Ice Shelf Breakup Mechanisms  

Microsoft Academic Search

The disintegration of various ice shelves on the Antarctic Peninsula has demonstrated their vulnerability and impacts on tributary glaciers. A satellite image of Wilkins Ice Shelf (WIS) from July of 2007 reveals the formation of a large new double fracture, accompanied by numerous small fractures. We show that bending stresses induced by buoyancy forces were responsible for fracture formation. On

Matthias Braun; Angelika Humbert

2009-01-01

445

Probing the Nucleus with Deuteron+Gold Collisions at RHIC  

NASA Astrophysics Data System (ADS)

The Relativistic Heavy Ion Collider (RHIC) was built to produce and study Quark Gluon Plasma (QGP), the phase of matter thought to exist under conditions sufficiently hot and dense to create a medium in which the degrees of freedom are quarks and gluons rather than color neutral hadrons. Already in its early years of running, the data from RHIC provided tantalizing evide