Target-charge dependence of the breakup coupling effects in the elastic scattering of {sup 8}B
Energy Technology Data Exchange (ETDEWEB)
Kucuk, Y. [University of Padova, Department of Physics and Astronomy ' ' G. Galilei' ' (Italy); Akdeniz University, Department of Physics, Antalya (Turkey); INFN, Padova (Italy); Aciksoz, E. [Technische Universitaet Darmstadt, Institut fuer Kernphysik, Darmstadt (Germany); Akdeniz University, Department of Physics, Antalya (Turkey)
2016-04-15
We perform continuum discretized coupled-channels calculations for the elastic scattering of {sup 8}B on different targets to trace where the Coulomb-nuclear breakup coupling effects start to be dominant in the interaction of the proton halo nuclei. We observe a qualitative difference in angular distributions when the charge of the target increases as seen in the case of neutron halos, but the Coulomb-nuclear interference peak begins to disappear clearly at a relatively smaller value of Z{sub T} for the proton halos. (orig.)
Breakup of Spiral Waves in Coupled Hindmarsh-Rose Neurons
Institute of Scientific and Technical Information of China (English)
MA Jun; JIA Ya; TANG Jun; YANG Li-Jian
2008-01-01
@@ Breakup of spiral wave in the Hindmarsh-Rose neurons with nearest-neighbour couplings is reported.Appropriate initial values and parameter regions are selected to develop a stable spiral wave and then the Gauesian coloured noise with different intensities and correlation times is imposed on all neurons to study the breakup of spiral wave, respectively.Based on the mean field theory, the statistical factor of synchronization is defined to analyse the evolution of spiral wave.It is found that the stable rotating spiral wave encounters breakup with increasing intensity of Gaussian coloured noise or decreasing correlation time to certain threshold.
Status of breakup reaction theory
International Nuclear Information System (INIS)
Recent studies on breakup reactions with the continuum-discretized coupled-channels method are reviewed. The topics covered are: four-body breakup processes for 6He induced reaction, dynamical relativistic effects on Coulomb breakup, microscopic description of projectile breakup processes, description of ternary processes (new triple-α reaction rate) and new approach to inclusive breakup processes.
Coulomb and nuclear effects in breakup and reaction cross sections
Descouvemont, Pierre; Hussein, Mahir S
2016-01-01
We use a three-body Continuum Discretized Coupled Channel (CDCC) model to investigate Coulomb and nuclear effects in breakup and reaction cross sections. The breakup of the projectile is simulated by a finite number of square integrable wave functions. First we show that the scattering matrices can be split in a nuclear term, and in a Coulomb term. This decomposition is based on the Lippmann-Schwinger equation, and requires the scattering wave functions. We present two different methods to separate both effects. Then, we apply this separation to breakup and reaction cross sections of 7Li + 208Pb. For breakup, we investigate various aspects, such as the role of the alpha + t continuum, the angular-momentum distribution, and the balance between Coulomb and nuclear effects. We show that there is a large ambiguity in defining the 'Coulomb' and 'nuclear' breakup cross sections, since both techniques, although providing the same total breakup cross sections, strongly differ for the individual components. We suggest...
Dynamical Relativistic Effects in Breakup Processes of Halo Nuclei
Ogata, Kazuyuki
2009-01-01
The continuum-discretized coupled-channels (CDCC) method is used to study the breakup of weakly-bound nuclei at intermediate energies collisions. For large impact parameters, the Eikonal CDCC (E-CDCC) method was applied. The effects of Lorentz contraction on the nuclear and Coulomb potentials have been investigated in details. Such effects tend to increase cross sections appreciably. We also show that, for loosely-bound nuclei, the contribution of the so-called close field is small and can be neglected.
New treatment of breakup continuum in the method of continuum discretized coupled channels
Matsumoto, T; Ogata, K; Iseri, Y; Hiyama, E; Kamimura, M; Yahiro, M
2003-01-01
In the method of continuum discretized coupled channels (CDCC) for treating three-body processes in projectile breakup reactions, the discretization of continuous breakup channels is essential. We propose a practical method of the discretization. The validity of the method is numerically tested and confirmed for two realistic examples, $d+^{58}$Ni scattering at 80 MeV and $^{6}Li+^{40}$Ca scattering at 156 MeV. Calculated elastic and breakup S-matrix elements based on the new method converge as the number of discretized breakup channels is increased. The converged S-matrix element agrees with the exact one which is derived with average (Av) discretization established as an accurate method. The new discretization requires a smaller number of breakup channels than the Av method. The feasibility of the new method for more complicated reactions is also discussed.
Influence of melt superheat on breakup process of close-coupled gas atomization
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
In close-coupled gas atomization(CCGA), the influences of melt superheat on breakup process are fundamental to obtain desired or finer powder. Based on a series of Cu atomization experiment under different superheating conditions, the influences of melt superheat on breakup process were studied. Experimental results indicate that as the melt superheat is increased to 150, 200, 250 and 300 K, the mean particle size (D50) decreases consequently to 34.9, 32.3, 30.9 and 19.7 μm. Theoretical analysis reveals that the primary breakup and secondary breakup processes are close coupled, and the melt superheat radically influences the melt properties,and plays a crucial role on governing the filming process of primary breakup and the atomization modes of secondary breakup. There exists a strong nonlinear decrease of contact angle of melt to nozzle orifice wall when the superheat is increased from 250 K to 300 K,leading to a marked fall of the film thickness formed in primary breakup, and D50 of copper powders is therefore sharply reduced.However, the log-normal distribution feature of particle size has not been substantially improved.
Matsumoto, T; Ogata, K; Iseri, Y; Kamimura, M; Chiba, S; Yahiro, M
2004-01-01
We propose a fully quantum-mechanical method of treating four-body nuclear breakup processes in scattering of a projectile consisting of three constituents, by extending the continuum-discretized coupled-channels method. The three-body continuum states of the projectile are discretized by diagonalizing the internal Hamiltonian of the projectile with the Gaussian basis functions. For $^6$He+$^{12}$C scattering at 18 and 229.8 MeV, the validity of the method is tested by convergence of the elastic and breakup cross sections with respect to increasing the number of the basis functions. Effects of the four-body breakup and the Borromean structure of $^6$He on the elastic and total reaction cross sections are discussed.
Finite Range Effects on Fusion and/or Breakup of 6He+238U and 11Li+208Pb Systems
Institute of Scientific and Technical Information of China (English)
Sukhvinder S. Duhan; Manjeet Singh; Rajesh Kharab; H.C. Sharma
2011-01-01
We have studied the effects of the finite range of the interaction between the fragments of the projectile on the fusion and/or breakup of 6He+238U and 11 Li+208 Pb systems at near barrier energies within the framework of dynamic polarization potential approach.It has been found that at near barrier energies the maximum flux is lost to the breakup channel and at energies well above the Coulomb barrier the fusion coupled with the breakup channel opens up, initially with sharp rise and later becoming saturated at energy nearly twice of the Coulomb barrier.Further, it is found that the breakup cross section increases with the increasing range of the interaction between the fragments of the projectile while the fusion coupled with the breakup channel cross section decreases with the increasing range.
Coupled simulations of nozzle flow, primary fuel jet breakup, and spray formation
Berg, Eberhard von; Edelbauer, Wilfried; Alajbegović, Aleš; Tatschl, Reinhard; Volmajer, Martin; Kegl, Breda; Ganippa, Lionel C.
2012-01-01
Presented are two approaches for coupled simulations of the injector flow withspray formation. In the first approach the two-fluid model is used within the injector for the cavitating flow. A primary breakup model is then applied at the nozzle orifice where it is coupled with the standard discrete droplet model. In the second approach the Eulerian multi-fluid model is applied for both the nozzle and spray regions. The developed primary breakup model, used in both approaches, is based on local...
Description of Four-Body Breakup Reaction with the Method of Continuum-Discretized Coupled-Channels
Egami, Tomoaki; Ogata, Kazuyuki; Yahiro, Masanobu
2008-01-01
We present a method for smoothing discrete breakup $S$-matrix elements calculated by the method of continuum-discretized coupled-channels (CDCC). This smoothing method makes it possible to apply CDCC to four-body breakup reactions. The reliability of the smoothing method is confirmed for two cases, $^{58}$Ni($d$, $p n$) at 80 MeV and the $E1$ transition of $^6$He. We apply CDCC with the smoothing method to $^6$He breakup reaction at 22.5 MeV. Multi-step breakup processes are found to be important.
Breakup and finite-range effects on the 8B(d,n)9C reaction
Fukui, Tokuro; Yahiro, Masanobu
2014-01-01
The astrophysical factor of 8B(p,{\\gamma})9C at zero energy, S18(0), is determined by a three-body coupled-channels analysis of the transfer reaction 8B(d,n)9C at 14.4 MeV/nucleon. Effects of the breakup channels of deuteron are investigated with the continuum-discretized coupled-channels method (CDCC). It is found that the transfer process through the deuteron breakup states, its interference with that through the deuteron ground state in particular, gives a large increase in the transfer cross section. The finite-range effects with respect to the proton- neutron relative coordinate are found to be less than 5%. As a result of the present analysis, S18(0) = 33 +/- 10 eVb is obtained that is smaller than the result of the previous DWBA analysis by about 26%.
Continuum-discretized coupled-channels method for four-body breakup reactions
Kamimura, M; Hiyama, E; Ogata, K; Iseri, Y; Yahiro, M
2005-01-01
Development of the method of CDCC (Continuum-Discretized Coupled-Channels) from the level of three-body CDCC to that of four-body CDCC is reviewed. Introduction of the pseudo-state method based on the Gaussian expansion method for discretizing the continuum states of two-body and three-body projectiles plays an essential role in the development. Furthermore, introduction of the complex-range Gaussian basis functions is important to improve the CDCC for nuclear breakup so as to accomplish that for Coulomb and nuclear breakup. A successful application of the four-body CDCC to $^6$He+$^{12}$C scattering at 18 and 229.8 MeV is reported.
Projectile deformation effects in the breakup of $^{37}$Mg
Shubhchintak,; Shyam, R
2015-01-01
We study the breakup of $^{37}$Mg on Pb at 244MeV/u with the recently developed extended theory of Coulomb breakup within the post-form finite range distorted wave Born approximation that includes deformation of the projectile. Comparing our calculated cross section with the available Coulomb breakup data we determine the possible ground state configuration of $^{37}$Mg.
Ogata, Kazuyuki
2016-01-01
We re-examine the deuteron elastic breakup cross sections on 12C and 10Be at low incident energies, for which a serious discrepancy between the continuum-discretized coupled-channels method (CDCC) and the Faddeev-Alt-Grassberger-Sandhas theory (FAGS) was pointed out. We show the closed-channels neglected in the preceding study affect significantly the breakup cross section calculated with CDCC, resulting in good agreement with the result of FAGS.
Matsumoto, Takuma; Ogata, Kazuyuki; Yahiro, Masanobu
2009-01-01
We present a practical way of smoothing discrete breakup S-matrix elements calculated by the continuum-discretized coupled-channel method (CDCC). This method makes the smoothing procedure much easier. The reliability of the smoothing method is confirmed for the three-body breakup reactions, 58Ni(d,pn) at 80 MeV and 12C(6He,4He2n) at 229.8 MeV.
Breakup Effects on University Students' Perceived Academic Performance
Field, Tiffany; Diego, Miguel; Pelaez, Martha; Deeds, Osvelia; Delgado, Jeannette
2012-01-01
The Problem: Problems that might be expected to affect perceived academic performance were studied in a sample of 283 university students. Results: Breakup Distress Scale scores, less time since the breakup and no new relationship contributed to 16% of the variance on perceived academic performance. Variables that were related to academic…
Nuclear Interference effects in 8B sub-Coulomb breakup
Nunes, F. M.; Thompson, I.J.
1998-01-01
The breakup of $^8$B on $^{58}$Ni below the Coulomb barrier was measured recently with the aim of determining the Coulomb breakup components. We reexamine this reaction, and perform one step quantum-mechanical calculations that include E1, E2 and nuclear contributions. We show that the nuclear contribution is by no means negligible at the intermediate angular range where data was taken. Our results indicate that, for an accurate description of this reaction, Coulomb E1, E2 and nuclear process...
Effects of thermal quenching on the breakup of pyroclasts
Patel, A.; Manga, M.; Carey, R. J.; Degruyter, W.; Dufek, J.
2012-12-01
wet density increased 0 to 2.5 %, as measured after 5 minutes immersion in water. Overall we see modest differences between quenched pumice and regular pumice in breakup, abrasion, mass, and effective wet density. Experimental results suggest that quenching may damage small parts of a clast but tends not to cause cracks that propagate easily through the clast. XRT and SEM imaging confirms that quenching only damages small external parts. This is in stark contrast to non-vesicular glass that develops large cracks on quenching.
Mukeru, B.; Lekala, M. L.
2016-08-01
In this paper we analyze the effects of the projectile resonances on the total, Coulomb, and nuclear breakup cross sections as well as on the Coulomb-nuclear interferences at different arbitrary incident energies. It is found that these resonances have non-negligible effects on the total, Coulomb, and nuclear breakup cross sections. Qualitatively, they have no effects on the constructiveness or destructiveness of the Coulomb-nuclear interferences. Quantitatively, we obtained that these resonances increase by 7.38%, 7.58%, and 20.30% the integrated total, Coulomb, and nuclear breakup cross sections, respectively at Elab=35 MeV . This shows that the nuclear breakup cross sections are more affected by the effects of the projectile resonances than their total and Coulomb breakup counterparts. We also obtain that the effects of the resonances on the total, Coulomb, and nuclear breakup cross sections decrease as the incident energy increases.
Ogata, K; Iseri, Y; Kamimura, M; Yahiro, M
2006-01-01
The astrophysical factor for 7Be(p,\\gamma)8B at zero energy, S17(0), is determined from 208Pb(8B, p+7Be)208Pb at 52 MeV/nucleon. We use the method of continuum-discretized coupled-channels (CDCC) to accurately calculate the 8B breakup cross section, taking account of nuclear breakup, Coulomb dipole and quadrupole transitions and higher-order processes. The asymptotic normalization coefficient (ANC) method is used to extract S17(0) from the calculated breakup-cross-section. The main result of the present paper is S17(0)=21.4 +2.0/-1.9 eV b. This result has +4.5%/-2.6% theoretical error, which comes from ambiguity of the p-7Be scattering length, and 8.4% systematic experimental error. CDCC calculation with one-step Coulomb dipole transitions results in a smaller value of S17(0), 20.2 eV b, which is almost consistent with the extracted value with the first-order perturbation theory: 18.9 eV b. Inclusion of Coulomb quadrupole transitions in one-step CDCC calculation is found to give further reduction of S17(0), i...
Effects of the geometric orientations of the nozzle exit on the breakup of free liquid jet
Energy Technology Data Exchange (ETDEWEB)
Lad, V. N.; Murthy, Z. V. P. [Sardar Vallabhbhai National Institute of Technology, Gujarat (India)
2016-04-15
Free liquid jets are produced through various geometric orientations of the nozzle exit. The breakup lengths of liquid jets under various geometric orientations of the nozzle exit were studied. Images of jets were captured using a high-speed camera with a maximum frame rate of 1000 frames per second and were analyzed to determine the dynamics between jets and breakup lengths. The breakup length of jets changes with the cut angle of the nozzle exit. In addition, adding polymer reduces the effect of the cut angle of the nozzle exit on the breakup length for an entire range of velocities. The effect of the cut angle on breakup length is predominant for aqueous solutions with surfactants. This work provides motivation for further computational research to study jet dynamics in a partially covered nozzle exit, such as the case in which the boundary conditions near the nozzle opening is more complex with the cut angle and its vertex position, which directly reflects liquid jet dynamics.
Spatial versus temporal deterministic wave breakup of nonlinearly coupled light waves.
Salerno, D; Minardi, S; Trull, J; Varanavicius, A; Tamosauskas, G; Valiulis, G; Dubietis, A; Caironi, D; Trillo, S; Piskarskas, A; Di Trapani, P
2003-10-01
We investigate experimentally the competition between spatial and temporal breakup due to modulational instability in chi((2)) nonlinear mixing. The modulation of the wave packets caused by the energy exchange between fundamental and second-harmonic components is found to be the prevailing trigger mechanism which, according to the relative weight of diffraction and dispersion, leads to the appearance of a multisoliton pattern in the low-dimensional spatial or temporal domain.
Breakup Effect of Weakly Bound Projectile on the Barrier Distribution Around Coulomb Barrier
Institute of Scientific and Technical Information of China (English)
贾会明; 林承键; 张焕乔; 刘祖华; 喻宁; 杨峰; 徐新星; 贾飞; 吴振东; 张世涛
2012-01-01
The excitation function of quasi-elastic （QEL） scattering at a backward angle has been measured for 9^Be＋208^Pb. The barrier distribution was extracted by means of the first derivative of the measured excitation function and calculated with the coupled-channel model. The present work shows that the experimental barrier distribution extracted from QEL scattering is shifted to the low energy side by 1.5 MeV as compared with the theoretical one. This energy discrepancy indicates that breakup is important in the colliding processes of the weakly bound nucleus system.
Effects of nuclear breakup channel on fusion of 6Li+64Zn system around barrier energies
International Nuclear Information System (INIS)
We have studied the effects of breakup, occurring due to the nuclear interaction between weakly bound 6Li and tightly bound 64Zn isotopes, on the fusion reaction at near barrier energies within the framework of dynamic polarization potential (DPP) approach. When the nuclear induced dynamic polarization potential is taken into account sub barrier enhancement and above barrier suppression have been found which improves the matching between the fusion excitation function data and predictions for 6Li+64Zn system significantly. (author)
Gupta, Anupam
2015-01-01
The effects of viscoelasticity on the dynamics and break-up of fluid threads in microfluidic T-junctions are investigated using numerical simulations of dilute polymer solutions at changing the Capillary number ($\\mbox {Ca}$), i.e. at changing the balance between the viscous forces and the surface tension at the interface, up to $\\mbox{Ca} \\approx 3 \\times 10^{-2}$. A Navier-Stokes (NS) description of the solvent based on the lattice Boltzmann models (LBM) is here coupled to constitutive equations for finite extensible non-linear elastic dumbbells with the closure proposed by Peterlin (FENE-P model). We present the results of three-dimensional simulations in a range of $\\mbox{Ca}$ which is broad enough to characterize all the three characteristic mechanisms of breakup in the confined T-junction, i.e. ${\\it squeezing}$, ${\\it dripping}$ and ${\\it jetting}$ regimes. The various model parameters of the FENE-P constitutive equations, including the polymer relaxation time $\\tau_P$ and the finite extensibility para...
Kistryn, S; Bodek, K; Ciepal, I; Deltuva, A; Fonseca, A; Kalantar-Nayestanaki, N; Kis, M; Klos, B; Kozela, A; Mahjour-Shafiei, M; Micherdzinska, A; Sauer, P U; Stephan, E; Sworst, R; Zejma, J; Zipper, W; Kistryn, St.
2006-01-01
High precision cross-section data of the deuteron-proton breakup reaction at 130 MeV deuteron energy are compared with the theoretical predictions obtained with a coupled-channel extension of the CD Bonn potential with virtual Delta-isobar excitation, without and with inclusion of the long-range Coulomb force. The Coulomb effect is studied on the basis of the cross-section data set, extended in this work to about 1500 data points by including breakup geometries characterized by small polar angles of the two protons. The experimental data clearly prefer predictions obtained with the Coulomb interaction included. The strongest effects are observed in regions in which the relative energy of the two protons is the smallest.
Cook, K. J.; Simpson, E. C.; Luong, D. H.; Kalkal, Sunil; Dasgupta, M.; Hinde, D. J.
2016-06-01
Background: Complete fusion cross sections in collisions of light weakly bound nuclei and high-Z targets show suppression of complete fusion at above-barrier energies. This has been interpreted as resulting from the breakup of the weakly bound nucleus prior to reaching the fusion barrier, reducing the probability of complete charge capture. Below-barrier studies of reactions of 9Be have found that the breakup of 8Be formed by neutron stripping dominates over direct breakup and that transfer-triggered breakup may account for the observed suppression of complete fusion. Purpose: This paper investigates how the above conclusions are affected by lifetimes of the resonant states that are populated prior to breakup. If the mean life of a populated resonance (above the breakup threshold) is much longer than the fusion time scale, then its breakup (decay) cannot suppress complete fusion. For short-lived resonances, the situation is more complex. This work explicitly includes the mean life of the short-lived 2+ resonance in 8Be in classical dynamical model calculations to determine its effect on energy and angular correlations of the breakup fragments and on model predictions of suppression of cross sections for complete fusion at above-barrier energies. Method: Previously performed coincidence measurements of breakup fragments produced in reactions of 9Be with 144Sm, 168Er, 186W, 196Pt, 208Pb, and 209Bi at energies below the barrier have been reanalyzed using an improved efficiency determination of the BALiN detector array. Predictions of breakup observables and of complete and incomplete fusion at energies above the fusion barrier are then made using the classical dynamical simulation code platypus, modified to include the effect of lifetimes of resonant states. Results: The agreement of the breakup observables is much improved when lifetime effects are included explicitly. Sensitivity to subzeptosecond lifetime is observed. The predicted suppression of complete fusion
Tymms, V. J.; Kusznir, N. J.
2004-12-01
The effect of temperature dependent rheology has been examined for a model of continental lithosphere thinning by an upwelling divergent flow field within continental lithosphere and asthenosphere leading to continental breakup and rifted continental margin formation. The model uses a coupled FE fluid flow and thermal solution and is kinematically driven using a half divergence rate Vx and upwelling velocity Vz. Viscosity structure is modified by the evolving temperature field of the model through the temperature dependent Newtonian rheology. Continental lithosphere and asthenosphere material are advected by the fluid-flow field in order to predict crustal and mantle lithosphere thinning leading to rifted continental margin formation. The results of the temperature dependent rheology model are compared with those of a simple isoviscous model. The temperature dependent rheology model predicts continental lithosphere thinning and depth dependent stretching, similar to that predicted by the uniform viscosity model. However compared with the uniform viscosity model the temperature dependent rheology predicts greater amounts of thinning of the continental crust and lithospheric mantle than the isoviscous solutions. An important parameter within the kinematic model of continental lithosphere breakup and rifted continental margin development is the velocity ratio Vz/Vx. For non-volcanic margins, Vz/Vx is thought to be around unity. Applying a velocity ratio Vz/Vx of unity gives a diffuse ocean-continent transition and exhumation of continental lithospheric mantle. For volcanic margins, Vz/Vx is of order 10, falling to unity with a half-life of order 10 Ma, leading to a more sharply defined ocean-continent transition. While Vx during continental breakup may be estimated, Vz can only be inferred. FE fluid flow solutions, in which Vz is not imposed and without an initial buoyancy driven flow component, predict a velocity ratio Vz/Vx of around unity for both temperature
Lum, Lydia
2011-01-01
This article reports on the breakup between Texas Southmost College (TSC) and the upper-division University of Texas at Brownsville (UTB). The split marks the official end of an unusual 20-year partnership between TSC and the University of Texas System that, for the first time, ushered four-year university education into overwhelmingly Latino…
The Effect of Corporate Break-ups on Information Asymmetry: A Market Microstructure Analysis
Bardong, Florian; Bartram, Söhnke M.; Yadav, Pradeep K.
2006-01-01
This paper investigates the information environment during and after a corporate break-up utilizing direct measures of information asymmetry developed in the market microstructure literature. The analysis is based on all corporate break-ups in the United States in the period 1995-2005. The results document that information asymmetry declines significantly as a result of a break-up. However, this reduction takes place not at the time of its announcement or its completion, but after it has been...
Cook, K J; Luong, D H; Kalkal, Sunil; Dasgupta, M; Hinde, D J
2016-01-01
Complete fusion cross sections in collisions of light, weakly bound nuclei and high Z targets show above-barrier suppression of complete fusion. This has been interpreted as resulting from breakup of the weakly bound nucleus prior to reaching the fusion barrier, reducing the probability of complete fusion. This paper investigates how these conclusions are affected by lifetimes of the resonant states that are populated prior to breakup. If the mean life of a populated resonance is much longer than the fusion timescale, then its breakup cannot suppress complete fusion. For short-lived resonances, the situation is more complex. This work includes the mean life of the short-lived 2+ resonance in 8Be in classical dynamical model calculations to determine its effect on energy and angular correlations of the breakup fragments and on predictions of fusion suppression. Coincidence measurements of breakup fragments produced in reactions of 9Be with 144Sm, 168Er, 186W, 196Pt, 208Pb and 209Bi at energies below the barrie...
Role of projectile breakup effects and intrinsic degrees of freedom on fusion dynamics
Singh Gautam, Manjeet
2016-05-01
This article analyzes the fusion dynamics of loosely bound and stable projectiles with Zr-target isotopes within the context of the coupled channel approach and the energy-dependent Woods-Saxon potential model (EDWSP model). In the case of the 28Si + 90Zr reaction, the coupling to the inelastic surface excitations results in an adequate description of the observed fusion dynamics while in case of the 28Si + 94Zr reaction, the coupling to collective surface vibrational states as well as the neutron (multi-neutron) transfer channel is necessary in the coupled channel calculations to reproduce the below-barrier fusion data. However, the EDWSP model calculation provides an accurate explanation of the fusion data of 28Si + 90,94Zr reactions in the domain of the Coulomb barrier. In the fusion of the 6Li + 90Zr reaction, the inclusion of the nuclear structure degrees of freedom recovers the observed sub-barrier fusion enhancement but results in suppression of the above barrier fusion data by 34% with respect to the coupled channel calculations. Using EDWSP model calculations, this suppression factor is reduced by 14% and consequently, the above-barrier fusion data of 6Li + 90Zr reaction is suppressed by 20% with reference to the EDWSP model calculations. Such fusion suppression at above-barrier energies can be correlated with the breakup of the projectile (6Li) before reaching the fusion barrier, as a consequence of low binding energy. Supported by Dr. D. S. Kothari Post-Doctoral Fellowship Scheme sponsored by University Grants Commission (UGC), New Delhi, India
Experimental study of relativistic effects in the dp breakup reaction using the WASA detector
Directory of Open Access Journals (Sweden)
Kłos B.
2014-03-01
Full Text Available An experiment to investigate the 1H(d→$\\overrightarrow d $, ppn breakup reaction at 340 MeV, 360 MeV and 400 MeV deuteron beam energy has been performed at the Cooler Synchrotron COSY-Jülich with the WASA detector. The main goal was to study of various aspects of few-nucleon dynamics in the medium energy region, with a particular emphasis on relativistic effects and their interplay with three nucelon forces. The almost 4π geometry of the WASA detector gives an unique possibility to study the different aspects of nucleon-nucleon dynamics in the three nucleon system. The preliminary analysis of the collected data is presented.
Effect of Air Entrainment on Breakup of Plunging Liquid Jet into Water Pool
International Nuclear Information System (INIS)
The steam explosion intensity is largely dependent upon the degree of volumetric fractions of melt droplets and steam in the fuel-coolant mixture. The rate of melt jet breakup and droplet sizes are, therefore, the key physical parameters in the analysis of FCIs. In a recent OECD/NEA international program SERENA, the areas where research may be needed to reduce the level of uncertainties in the code predictions have been identified. The predicted void fractions in the mixture were generally much higher than experimental data and a deficiency in melt jet breakup modeling would be one of the primary causes. In this paper, an extended study of non-boiling liquid jet breakup from the previous jet breakup experiment is reported with an emphasis on the role of air entrainment by plunging liquid jet into water pool. An improved jet breakup model is also presented with comparison to the experimental data. Non-boiling liquid jet breakup experiment was conducted and the debris size was analyzed with a new jet breakup model with an emphasis on the role of air entrainment. The predicted debris size with consideration of entrained air showed good agreement with the experimental data
Effect of Air Entrainment on Breakup of Plunging Liquid Jet into Water Pool
Energy Technology Data Exchange (ETDEWEB)
Kim, Hyoungtak; Bang, Kwanghyun [Korea Maritime Univ., Busan (Korea, Republic of)
2013-05-15
The steam explosion intensity is largely dependent upon the degree of volumetric fractions of melt droplets and steam in the fuel-coolant mixture. The rate of melt jet breakup and droplet sizes are, therefore, the key physical parameters in the analysis of FCIs. In a recent OECD/NEA international program SERENA, the areas where research may be needed to reduce the level of uncertainties in the code predictions have been identified. The predicted void fractions in the mixture were generally much higher than experimental data and a deficiency in melt jet breakup modeling would be one of the primary causes. In this paper, an extended study of non-boiling liquid jet breakup from the previous jet breakup experiment is reported with an emphasis on the role of air entrainment by plunging liquid jet into water pool. An improved jet breakup model is also presented with comparison to the experimental data. Non-boiling liquid jet breakup experiment was conducted and the debris size was analyzed with a new jet breakup model with an emphasis on the role of air entrainment. The predicted debris size with consideration of entrained air showed good agreement with the experimental data.
Numerical simulation of mechanical breakup of river ice-cover
Institute of Scientific and Technical Information of China (English)
WANG Jun; HE Liang; CHEN Pang-pang; SUI Jueyi
2013-01-01
Ice jams and ice dams in rivers will cause significant rises of water levels.Under extreme conditions,the ice flooding during winter or early spring may occur.In this paper,by considering the fluid-solid coupling effect caused by the water and the ice cover,the mechanisms of the mechanical breakup of the river ice cover are studied.A formula is obtained for determining whether or not the mechanical breakup process would happen under the hydraulic pressure of the flow.Combined with the hydraulic model under the ice covered flow,a numerical model is built and the interaction between the discharge,the hydraulic pressure under the ice cover and the date for the mechanical breakup of the river ice cover is simulated.The simulated results of the dates for the mechanical breakup of the river ice cover agree very well with the field observations of the breakups of the river ice cover in the Hequ Reach of the Yellow River.Therefore,the numerical model might serve as a good preliminary step in studying the breakup of the river ice-cover,evidencing many important parameters that affect the ice-cover process.
Institute of Scientific and Technical Information of China (English)
X.H.Wang
2004-01-01
Floc breakup dynamics are studied by a sediment transport numerical model in an idealized tidal estuary that has a constant water depth and rapid flocculation of cohesive sediments. The focus is placed on the effects of boundary layer stratification induced by a bottom nepheloid layer on floc breakup and size distribution in the water column. In a neutrally stratified estuary, the floc size distribution follows a parabolic function with maximum values at the surface and bottom. The sediment-induced stratification in the bottom boundary layer increases the median floc sizes. Furthermore, sediment-voided convection caused by the settling lutocline generates significant turbulent kinetic energy dissipation and reduces floc size at the depth where the convective mixing happens. Below that depth, a weak local maxima in the floc size is predicted due to presence of the lutocline. The effect of sediment-stratified bottom boundary layer on the floc breakup can be consistently approximated by a linear regression between the maximal floc size and flux Richardson number.
Matsumoto, T; Iseri, Y; Kamimura, M; Ogata, K; Yahiro, M
2006-01-01
We accurately analyze the $^6$He+$^{209}$Bi scattering at 19 and 22.5 MeV near the Coulomb barrier energy, using the continuum-discretized coupled-channels method (CDCC) based on the $n$+$n$+$^4$He+$^{209}$Bi four-body model. The three-body breakup continuum of $^6$He is discretized by diagonalizing the internal Hamiltonian of $^6$He in a space spanned by the Gaussian basis functions. The calculated elastic and total reaction cross sections are in good agreement with the experimental data, while the CDCC calculation based on the di-neutron model of $^6$He, i.e., the $^2n$+$^{4}$He+$^{209}$Bi three-body model, does not reproduce the data.
Satellite Breakup Risk Mitigation
Leleux, Darrin P.; Smith, Jason T.
2006-01-01
Many satellite breakups occur as a result of an explosion of stored energy on-board spacecraft or rocket-bodies. These breakups generate a cloud of tens or possibly hundreds of thousands of debris fragments which may pose a transient elevated threat to spaceflight crews and vehicles. Satellite breakups pose a unique threat because the majority of the debris fragments are too small to be tracked from the ground. The United States Human Spaceflight Program is currently implementing a risk mitigation strategy that includes modeling breakup events, establishing action thresholds, and prescribing corresponding mitigation actions in response to satellite breakups.
The effects of turbulence on droplet drag and secondary droplet breakup
Song, Y.-H.; Coy, E.; Greenfield, S.; Ondas, M.; Prevish, T.; Spegar, T.; Santavicca, D.
1994-01-01
The objective of this research is to obtain an improved understanding of the behavior of droplets in vaporizing sprays, particularly under conditions typical of those in high pressure rocket sprays. Experiments are conducted in a variety of high pressure, high temperature, optically-accessible flow systems, including one which is capable of operation at pressures up to 70 atm, temperatures up to 600 K, gas velocities up to 30 m/sec and turbulence intensities up to 40 percent. Single droplets, 50 to 500 micron in diameter, are produced by an aerodynamic droplet generator and transversely injected into the flow. Measurements are made of the droplet position, size, velocity and temperature and of the droplet's vapor wake from which droplet drag, dispersion, heating, vaporization and breakup are characterized.
Gaussian expansion approach to Coulomb breakup
Egami, T; Matsumoto, T; Iseri, Y; Kamimura, M; Yahiro, M
2004-01-01
An accurate treatment of Coulomb breakup reactions is presented by using both the Gaussian expansion method and the method of continuum discretized coupled channels. As $L^2$-type basis functions for describing Coulomb breakup processes, we take complex-range Gaussian functions, which form in good approximation a complete set in a large configuration space being important for the processes. Accuracy of the method is tested quantitatively for $^{8}{\\rm B}+^{58}$Ni scattering at 25.8 MeV.
Regehr, E.V.; Lunn, N.J.; Amstrup, Steven C.; Stirling, I.
2007-01-01
Some of the most pronounced ecological responses to climatic warming are expected to occur in polar marine regions, where temperature increases have been the greatest and sea ice provides a sensitive mechanism by which climatic conditions affect sympagic (i.e., with ice) species. Population-level effects of climatic change, however, remain difficult to quantify. We used a flexible extension of Cormack-Jolly-Seber capture-recapture models to estimate population size and survival for polar bears (Ursus maritimus), one of the most ice-dependent of Arctic marine mammals. We analyzed data for polar bears captured from 1984 to 2004 along the western coast of Hudson Bay and in the community of Churchill, Manitoba, Canada. The Western Hudson Bay polar bear population declined from 1,194 (95% CI = 1,020-1,368) in 1987 to 935 (95% CI = 794-1,076) in 2004. Total apparent survival of prime-adult polar bears (5-19 yr) was stable for females (0.93; 95% CI = 0.91-0.94) and males (0.90; 95% CI = 0.88-0.91). Survival of juvenile, subadult, and senescent-adult polar bears was correlated with spring sea ice breakup date, which was variable among years and occurred approximately 3 weeks earlier in 2004 than in 1984. We propose that this correlation provides evidence for a causal association between earlier sea ice breakup (due to climatic warming) and decreased polar bear survival. It may also explain why Churchill, like other communities along the western coast of Hudson Bay, has experienced an increase in human-polar bear interactions in recent years. Earlier sea ice breakup may have resulted in a larger number of nutritionally stressed polar bears, which are encroaching on human habitations in search of supplemental food. Because western Hudson Bay is near the southern limit of the species' range, our findings may foreshadow the demographic responses and management challenges that more northerly polar bear populations will experience if climatic warming in the Arctic continues as
Zhang Liang; He Zhixia; Wang Qian; Guo Genmiao
2015-01-01
To research an effective measure of reducing the Soot and NOx in engine at the same time, different nozzle hole diameters coupled with exhaust gas recirculation (EGR) were adopted in this study based on KH-ACT spray breakup model, which takes the aerodynamic-induced ,cavitation-induced and turbulence-induced breakup into account. The SAGE detailed chemistry combustion and the new atomization model used in the simulation have been verified with the experimen...
Visualization of Atomization Gas Flow and Melt Break-up Effects in Response to Nozzle Design
Energy Technology Data Exchange (ETDEWEB)
Anderson, Iver; Rieken, Joel; Meyer, John; Byrd, David; Heidloff, Andy
2011-04-01
Both powder particle size control and efficient use of gas flow energy are highly prized goals for gas atomization of metal and alloy powder to minimize off-size powder inventory (or 'reverb') and excessive gas consumption. Recent progress in the design of close-coupled gas atomization nozzles and the water model simulation of melt feed tubes were coupled with previous results from several types of gas flow characterization methods, e.g., aspiration measurements and gas flow visualization, to make progress toward these goals. Size distribution analysis and high speed video recordings of gas atomization reaction synthesis (GARS) experiments on special ferritic stainless steel alloy powders with an Ar+O{sub 2} gas mixture were performed to investigate the operating mechanisms and possible advantages of several melt flow tube modifications with one specific gas atomization nozzle. In this study, close-coupled gas atomization under closed wake gas flow conditions was demonstrated to produce large yields of ultrafine (dia.<20 {mu}m) powders (up to 32%) with moderate standard deviations (1.62 to 1.99). The increased yield of fine powders is consistent with the dual atomization mechanisms of closed wake gas flow patterns in the near-field of the melt orifice. Enhanced size control by stabilized pre-filming of the melt with a slotted trumpet bell pour tube was not clearly demonstrated in the current experiments, perhaps confounded by the influence of the melt oxidation reaction that occurred simultaneously with the atomization process. For this GARS variation of close-coupled gas atomization, it may be best to utilize the straight cylindrical pour tube and closed wake operation of an atomization nozzle with higher gas mass flow to promote the maximum yields of ultrafine powders that are preferred for the oxide dispersion strengthened alloys made from these powders.
The Effect of Marital Breakup on the Income Distribution of Women with Children
Ananat, Elizabeth O.; Michaels, Guy
2008-01-01
Having a female first-born child significantly increases the probability that a woman's first marriage breaks up. Using this exogenous variation, recent work finds that divorce has little effect on women's mean household income. We further investigate the effect of divorce using Quantile Treatment Effect methodology and find that it increases…
Papageorgiou, Demetrios T.
1996-01-01
In this article we review recent results on the breakup of cylindrical jets of a Newtonian fluid. Capillary forces provide the main driving mechanism and our interest is in the description of the flow as the jet pinches to form drops. The approach is to describe such topological singularities by constructing local (in time and space) similarity solutions from the governing equations. This is described for breakup according to the Euler, Stokes or Navier-Stokes equations. It is found that slender jet theories can be applied when viscosity is present, but for inviscid jets the local shape of the jet at breakup is most likely of a non-slender geometry. Systems of one-dimensional models of the governing equations are solved numerically in order to illustrate these differences.
Study on the breakup length of circular impinging jet
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
Circular impinging jet, which is widely used in accelerated control cooling (ACC) equipment to accelerate the cooling of hot rolled plates, is subject to breakup, and may result in undesirable cooling effect. Therefore, the jet breakup should be avoided as possible in industrial production. The objective of this study is to find the relation of the processing parameters of the ACC equipment versus the breakup length of jet with weaker turbulence. To obtain quantitative findings, not only relative experimental study but also numerical simulation was carried out. For a weaker turbulent water jet, the breakup length increases with the increase of jet diameter, as well as with the jet velocity; jet diameter has a significant effect on the breakup length for a certain flow rate when compared with jet velocity; finally a suggested correlation of the jet breakup length versus jet Weber number is presented in this study.
Magmatism during Gondwana breakup
DEFF Research Database (Denmark)
van der Meer, Quinten; Scott, J.M.; Waight, Tod Earle;
2013-01-01
Newly determined mid-late Cretaceous 40Ar/39Ar ages on megacrystic kaersutite from lamprophyre dikes in central and north Westland (New Zealand) are presented. These ages (88 Ma, 86 Ma and 68 Ma) indicate that the intrusion of mafic dikes was not necessarily restricted to the previously establish...... did not only precede Tasman Sea initiation (starting at ~83 Ma, lasting to ~53 Ma) but may have sporadically continued for up to 15 Myr after continental breakup....
Exact Bremsstrahlung and effective couplings
Mitev, Vladimir; Pomoni, Elli
2016-06-01
We calculate supersymmetric Wilson loops on the ellipsoid for a large class of mathcal{N} = 2 SCFT using the localization formula of Hama and Hosomichi. From them we extract the radiation emitted by an accelerating heavy probe quark as well as the entanglement entropy following the recent works of Lewkowycz-Maldacena and Fiol-Gerchkovitz-Komargodski. Comparing our results with the mathcal{N} = 4 SYM ones, we obtain interpolating functions f ( g 2) such that a given mathcal{N} = 2 SCFT observable is obtained by replacing in the corresponding mathcal{N} = 4 SYM result the coupling constant by f ( g 2). These "exact effective couplings" encode the finite, relative renormalization between the mathcal{N} = 2 and the mathcal{N} = 4 gluon propagator and they interpolate between the weak and the strong coupling. We discuss the range of their applicability.
Exact Bremsstrahlung and effective couplings
Energy Technology Data Exchange (ETDEWEB)
Mitev, Vladimir [Mainz Univ. (Germany). Inst. fuer Physik, WA THEP; Humboldt-Univ. Berlin (Germany). Inst. fuer Mathematik und Inst. fuer Physik; Pomoni, Elli [DESY Hamburg (Germany). Theory Group; National Technical Univ., Athens (Greece). Physics Div.
2015-11-15
We calculate supersymmetric Wilson loops on the ellipsoid for a large class of N=2 SCFT using the localization formula of Hama and Hosomichi. From them we extract the radiation emitted by an accelerating heavy probe quark as well as the entanglement entropy following the recent works of Lewkowycz-Maldacena and Fiol-Gerchkovitz-Komargodski. Comparing our results with the N=4 SYM ones, we obtain interpolating functions f(g{sup 2}) such that a given N=2 SCFT observable is obtained by replacing in the corresponding N=4 SYM result the coupling constant by f(g{sup 2}). These ''exact effective couplings'' encode the finite, relative renormalization between the N = 2 and the N = 4 gluon propagator, they interpolate between the weak and the strong coupling. We discuss the range of their applicability.
Exact Bremsstrahlung and effective couplings
International Nuclear Information System (INIS)
We calculate supersymmetric Wilson loops on the ellipsoid for a large class of N=2 SCFT using the localization formula of Hama and Hosomichi. From them we extract the radiation emitted by an accelerating heavy probe quark as well as the entanglement entropy following the recent works of Lewkowycz-Maldacena and Fiol-Gerchkovitz-Komargodski. Comparing our results with the N=4 SYM ones, we obtain interpolating functions f(g2) such that a given N=2 SCFT observable is obtained by replacing in the corresponding N=4 SYM result the coupling constant by f(g2). These ''exact effective couplings'' encode the finite, relative renormalization between the N = 2 and the N = 4 gluon propagator, they interpolate between the weak and the strong coupling. We discuss the range of their applicability.
Exact Bremsstrahlung and Effective Couplings
Mitev, Vladimir
2015-01-01
We calculate supersymmetric Wilson loops on the ellipsoid for a large class of $\\mathcal{N}=2$ SCFT using the localization formula of Hama and Hosomichi. From them we extract the radiation emitted by an accelerating heavy probe quark as well as the entanglement entropy following the recent works of Lewkowycz-Maldacena and Fiol-Gerchkovitz-Komargodski. Comparing our results with the $\\mathcal{N}=4$ SYM ones, we obtain interpolating functions $f(g^2)$ such that a given $\\mathcal{N}=2$ SCFT observable is obtained by replacing in the corresponding $\\mathcal{N}=4$ SYM result the coupling constant by $f(g^2)$. These ``exact effective couplings'' encode the finite, relative renormalization between the $\\mathcal{N}=2$ and the $\\mathcal{N}=4$ gluon propagator, they interpolate between the weak and the strong coupling. We discuss the range of their applicability.
Properties of nuclear and Coulomb breakup of 8B
Ogata, K; Iseri, Y; Yahiro, M
2008-01-01
Dependence of breakup cross sections of 8B at 65 MeV/nucleon on target mass number A_T is investigated by means of the continuum-discretized coupled-channels method (CDCC) with more reliable distorting potentials than in preceding study. The scaling law of the nuclear breakup cross section as A_T^(1/3) is found to be satisfied only in the middle A_T region of 40 < A_T < 150. Interference between nuclear and Coulomb breakup amplitudes turns out to vanish at very forward angles with respect to the center-of-mass of 8B, independent of target nucleus. Truncation of the relative energy between the p and 7Be fragments slightly reduces contribution from nuclear breakup at very forward angles, while the angular region in which the first-order perturbation theory works well does not change essentially.
Elastic Coulomb breakup of $^{34}$Na
Singh, G; Chatterjee, R
2016-01-01
Purpose : The aim of this paper is to study the elastic Coulomb breakup of $^{34}$Na on $^{208}$Pb to give us a core of $^{33}$Na with a neutron and in the process we try and investigate the one neutron separation energy and the ground state configuration of $^{34}$Na. Method : A fully quantum mechanical Coulomb breakup theory within the architecture of post-form finite range distorted wave Born approximation extended to include the effects of deformation is used to research the elastic Coulomb breakup of $^{34}$Na on $^{208}$Pb at 100 MeV/u. The triple differential cross-section calculated for the breakup is integrated over the desired components to find the total cross-section, momentum and angular distributions as well as the average momenta, along with the energy-angular distributions. Results : The total one neutron removal cross-section is calculated to test the possible ground state configurations of $^{34}$Na. The average momentum results along with energy-angular calculations indicate $^{34}$Na to ha...
International Nuclear Information System (INIS)
A Feed-and-bleed (F and B) operation is a process to cool the reactor by the primary side directly. If adequate residual heat removal through the secondary side is not available, the heat can be removed from the RCS by F and B operation. A total loss of feedwater (TLOFW) accident is used to represent an accident involving the failure of cooling by the secondary cooling system. Even if the secondary cooling system fails, the RCS can be cooled by F and B transients when a loss of coolant accident (LOCA) with a TLOFW accident occurs. During an F and B transient, the RCS has a residual heat removal mechanism. If the break size is large, an F and B transient continuously occurs if the SIS is available. If the break size is small to sufficiently decrease the RCS pressure, the SIS cannot inject the coolant, causing the F and B transient to terminate. After the termination of the F and B transient, the residual heat cannot be removed, and the necessity of an F and B operation increases. The operators may hesitate to initiate F and B operation if a clear cue is not provided, since its initiation implies the radioactive coolant releases into the containment. Therefore, the necessity of F and B operation is needed to be identified. The factors affected the necessity of F and B operation are the availability of the safety injection system and safety depressurization system, water inventory in the primary and secondary cooling systems, break size in a loss-of-coolant accident, and time of accident occurrence. The necessity of F and B operation can be changed according to different timing of break-up despite same break size. Moreover, different timing of break-up makes the operators more complicated. To identify effect of timing of break-up, a thermohydraulic analysis was performed using the MARS code. This study is expected to provide a useful guideline to identify the necessity of an F and B operation under combined accident
Numerical analysis of jet breakup behavior using particle method
International Nuclear Information System (INIS)
A continuous jet changes to droplets where jet breakup occurs. In this study, two-dimensional numerical analysis of jet breakup is performed using the MPS method (Moving Particle Semi-implicit Method) which is a particle method for incompressible flows. The continuous fluid surrounding the jet is neglected. Dependencies of the jet breakup length on the Weber number and the Froude number agree with the experiment. The size distribution of droplets is in agreement with the Nukiyama-Tanasawa distribution which has been widely used as an experimental correlation. Effects of the Weber number and the Froude number on the size distribution are also obtained. (author)
Numerical analysis of jet breakup behavior using particle method
International Nuclear Information System (INIS)
A continuous jet changes to droplets where jet breakup occurs. In this study, two-dimensional numerical analysis of jet breakup is performed using the MPS method (Moving Particle Semi-implicit Method) which is a particle method for incompressible flows. The continuous fluid surrounding the jet is neglected. Dependencies of the jet breakup length on the Waber number and the Froude number agree with the experiment. The size distribution of droplets is in agreement with the Nukiyama-Tanasawa distribution which has been widely used as an experimental correlation. Effects of the Weber number and the Froude number on the size distribution are also obtained. (author)
Numerical analysis of jet breakup behavior using particle method
International Nuclear Information System (INIS)
A continuous jet changes to droplets where jet breakup occurs. In this study, two-dimensional numerical analysis of jet breakup is performed using the MPS method (Moving Particle Semi-implicit Method) which is a particle method for incompressible flows. The continuous fluid surrounding the jet is neglected. Dependencies of the jet breakup length on the Weber number and the Froude number agree with the experiment. The size distribution of droplets is in agreement with the Nukiyama-Tanasawa distribution that has been widely used as an experimental correlation. Effects of the Weber number and the Froude number on the size distribution are also obtained. (author)
Dissociation of relativistic projectiles with the continuum-discretized coupled-channels method
Ogata, K
2008-01-01
Relativistic effects in the breakup of weakly-bound nuclei at intermediate energies are studied and compared with non-relativistic calculations. We show that relativistic corrections lead to larger breakup cross sections. Since many of these reactions can only be treated correctly if one accounts for the coupling between states in the continuum, we show that continuum-discretized coupled-channels calculations are also be strongly influenced by relativistic effects.
Breakup of spiral wave under different boundary conditions
Institute of Scientific and Technical Information of China (English)
Zhao Ying-Kui; Wang Guang-Rui; Chen Shi-Gang
2007-01-01
In this paper, we investigate the breakup of spiral wave under no-flux, periodic and Dirichlet boundary conditions respectively. When the parameter ε is close to a critical value for Doppler-induced wave breakup, the instability of the system caused by the boundary effect occurs in the last two cases, resulting in the breakup of spiral wave near the boundary. With our defined average order measure of spiral wave (AOMSW), we quantify the degree of order of the system when the boundary-induced breakup of spiral wave happens. By analysing the AOMSW and outer diameter R of the spiral tip orbit, it is easy to find that this boundary effect is correlated with large values of R, especially under the Dirichlet boundary condition. This correlation is nonlinear, so the AOMSW sometimes oscillates with the variation of ε.
11Li structural information from inclusive break-up measurements
Directory of Open Access Journals (Sweden)
Fernández-García J. P.
2015-01-01
Full Text Available Structure information of 11Li halo nucleus has been obtained from the inclusive break-up measurements of the 11Li+208Pb reactions at energies around the Coulomb barrier (Elab = 24.3 and 29.8 MeV. The effective break-up energy and the slope of B(E1 distribution close to the threshold have been extracted from the experimental data.
Study on breakup mechanism of unstable nuclei with CDCC
Matsumoto, T
2015-01-01
The continuum-discretized coupled-channels method (CDCC) has been successful in describing breakup reactions involving unstable nuclei. Moreover, CDCC is a useful method for evaluation of nuclear data, which are important for nuclear engineering. In this article, we present the theoretical foundation of CDCC and some results of CDCC analyses.
Progress in all-order breakup reaction theories
Indian Academy of Sciences (India)
R Chatterjee
2010-07-01
Progress in breakup reaction theories, like the distorted wave Born approximation, the continuum discretized coupled channels method and the dynamical eikonal approximation, is brought into focus. The need to calculate exclusive reaction observables and the utility of benchmark tests as arbitrators of theoretical models are discussed.
Beck, C; Keeley, N.; Diaz-Torres, A.
2007-01-01
The influence on fusion of coupling to the breakup process is investigated for reactions where at least one of the colliding nuclei has a sufficiently low binding energy for breakup to become an important process. Elastic scattering, excitation functions for sub-and near-barrier fusion cross sections, and breakup yields are analyzed for $^{6,7}$Li+$^{59}$Co. Continuum-Discretized Coupled-Channels (CDCC) calculations describe well the data at and above the barrier. Elastic scattering with $^{6...
Breakup of molten aluminum drops
International Nuclear Information System (INIS)
To clarify the entrapment of water and the breakup mechanism in molten Al drops, a series of experiments was carried out by pouring molten Al of 10 to 20 g (up to 1,000degC) into a highly subcooled-water pool (room temperature) through the air. A single large-scale water jet, which is capable of penetrating a molten Al drop, was found to appear above the molten Al drop immediately after an air column which the molten drop is dragging from the water surface, is detached. It was observed with a high frequency that a molten Al drop begins swelling first, and is then broken up during falling through the water pool or after hitting the basement. It was also found that the breakup always occurs in the course of solid crust formation, and the molten drop solidified without breakup forms a large cavity inside. Based on the experimental observations, it is concluded that the swelling and the breakup of a molten Al drop should be caused by the water entrapped inside and the hydrogen remaining super-saturated. It is reasonable to consider that an intensive breakup should be caused when some quantity of water is injected into a molten Al drop with a capability that a high-pressure vapor is generated due to a rapid release of latent heat just after brittle cracks occur during swelling. (author)
New technique for high-speed microjet breakup analysis
Energy Technology Data Exchange (ETDEWEB)
Vago, N. [Department of Atomic Physics, Budapest University of Technology and Economics, Budafoki ut 8, 1111, Budapest (Hungary); Synova SA, Ch. Dent d' Oche, 1024 Ecublens (Switzerland); Spiegel, A. [Department of Atomic Physics, Budapest University of Technology and Economics, Budafoki ut 8, 1111, Budapest (Hungary); Couty, P. [Institute of Imaging and Applied Optics, Swiss Federal Institute of Technology, Lausanne, BM, 1015, Lausanne (Switzerland); Wagner, F.R.; Richerzhagen, B. [Synova SA, Ch. Dent d' Oche, 1024 Ecublens (Switzerland)
2003-10-01
In this paper we introduce a new technique for visualizing the breakup of thin high-speed liquid jets. Focused light of a He-Ne laser is coupled into a water jet, which behaves as a cylindrical waveguide until the point where the amplitude of surface waves is large enough to scatter out the light from the jet. Observing the jet from a direction perpendicular to its axis, the light that appears indicates the location of breakup. Real-time examination and also statistical analysis of the jet disruption is possible with this method. A ray tracing method was developed to demonstrate the light scattering process. (orig.)
The Beam Break-Up Numerical Simulator
International Nuclear Information System (INIS)
Beam Break-Up (BBU) is a severe constraint in accelerator design, limiting beam current and quality. The control of BBU has become the focus of much research in the design of the next generation collider, recirculating and linear induction accelerators and advanced accelerators. Determining the effect on BBU of modifications to cavities, the focusing elements or the beam is frequently beyond the ability of current analytic models. A computer code was written to address this problem. The Beam Break-Up Numerical Simulator (BBUNS) was designed to numerically solve for beam break-up (BBU) due to an arbitrary transverse wakefield. BBUNS was developed to be as user friendly as possible on the Cray computer series. The user is able to control all aspects of input and output by using a single command file. In addition, the wakefield is specified by the user and read in as a table. The program can model energy variations along and within the beam, focusing magnetic field profiles can be specified, and the graphical output can be tailored. In this note we discuss BBUNS, its structure and application. Included are detailed instructions, examples and a sample session of BBUNS. This program is available for distribution. 50 refs., 18 figs., 5 tabs
The Beam Break-Up Numerical Simulator
Energy Technology Data Exchange (ETDEWEB)
Travish, G.A.
1989-11-01
Beam Break-Up (BBU) is a severe constraint in accelerator design, limiting beam current and quality. The control of BBU has become the focus of much research in the design of the next generation collider, recirculating and linear induction accelerators and advanced accelerators. Determining the effect on BBU of modifications to cavities, the focusing elements or the beam is frequently beyond the ability of current analytic models. A computer code was written to address this problem. The Beam Break-Up Numerical Simulator (BBUNS) was designed to numerically solve for beam break-up (BBU) due to an arbitrary transverse wakefield. BBUNS was developed to be as user friendly as possible on the Cray computer series. The user is able to control all aspects of input and output by using a single command file. In addition, the wakefield is specified by the user and read in as a table. The program can model energy variations along and within the beam, focusing magnetic field profiles can be specified, and the graphical output can be tailored. In this note we discuss BBUNS, its structure and application. Included are detailed instructions, examples and a sample session of BBUNS. This program is available for distribution. 50 refs., 18 figs., 5 tabs.
Inclusive breakup of Borromean nuclei
Hussein, Mahir S; Frederico, Tobias
2016-01-01
We derive the inclusive breakup cross section of a three-fragment projectile nuclei, $a = b +x_1 + x_2$, in the spectator model. The resulting four-body cross section for observing $b$, is composed of the elastic breakup cross section which contains information about the correlation between the two participant fragments, and the inclusive non-elastic breakup cross section. This latter cross section is found to be a non-trivial four-body generalization of the Austern formula \\cite{Austern1987}, which is proportional to a matrix element of the form, $\\langle\\hat{\\rho}_{{x_1},{x_2}}\\left|\\left[W_{{x_1}} + W_{{x_2}} + W_{3B}\\right]\\right|\\hat{\\rho}_{{x_1}, {x_2}}\\rangle$. The new feature here is the three-body absorption, represented by the imaginary potential, $W_{3B}$. We analyze this type of absorption and supply ideas of how to calculate its contribution.
Kistryn, S; Bodek, K; Deltuva, A; Epelbaum, E; Ermisch, K; Glöckle, W; Golak, J; Kalantar-Nayestanaki, N; Kamada, H; Kis, M; Klos, B; Kozela, A; Kuros-Zolnierczuk, J; Mahjour-Shafiei, M; Meißner, Ulf G; Micherdzinska, A; Nogga, A; Sauer, P U; Skibinski, R; Stephan, E; Sworst, R; Witala, H; Zejma, J; Zipper, W
2005-01-01
High precision cross-section data of the deuteron-proton breakup reaction at 130 MeV are presented for 72 kinematically complete configurations. The data cover a large region of the available phase space, divided into a systematic grid of kinematical variables. They are compared with theoretical predictions, in which the full dynamics of the three-nucleon (3N) system is obtained in three different ways: realistic nucleon-nucleon (NN) potentials are combined with model 3N forces (3NF's) or with an effective 3NF resulting from explicit treatment of the Delta-isobar excitation. Alternatively, the chiral perturbation theory approach is used at the next-to-next-to-leading order with all relevant NN and 3N contributions taken into account. The generated dynamics is then applied to calculate cross-section values by rigorous solution of the 3N Faddeev equations. The comparison of the calculated cross sections with the experimental data shows a clear prefernce for the predictions in which the 3NF's are included. The m...
Interplay of projectile breakup and target excitation in reactions induced by weakly-bound nuclei
Gomez-Ramos, M
2016-01-01
In this work, we reexamine the extension of the CDCC formalism to include target excitation and apply it to a variety of reactions to study the effect of breakup on inelastic cross sections. We use a transformed oscillator basis to discretize the continuum of the projectiles in the different reactions and use the extended CDCC method developed in this work to solve the resulting coupled differential equations. A new code has been developed to perform the calculations. Reactions 58Ni(d, d) 58Ni*, 24Mg(d, d) 24Mg* , 144Sm( 6Li, 6Li) 144Sm* and 9Be( 6Li, 6Li) 9Be* are studied. Satisfactory agreement is found between experimental data and extended CDCC calculations. The studied CDCC method is proved to be an accurate tool to describe target excitation in reactions with weakly-bound nuclei. Moderate effects of breakup on inelastic observables are found for the reactions studied. Cross section magnitudes are not modified much, but angular distributions present smoothing when opposed to calculations without breakup.
Comparison of axial and radial electron beam-breakup transit-time oscillators
Energy Technology Data Exchange (ETDEWEB)
Kwan, T.J.T. [Los Alamos National Lab., NM (United States); Mostrom, M.A. [Mission Research Corporation, Albuquerque, NM (United States)
1995-08-01
Comparison of two configurations of a novel high-power microwave generator is presented in this article. Coupling the beam-breakup instability with the transit-time effect of the electron beam in the cavity, rapid energy exchange between the electrons and cavity modes can occur. The dominant cavity modes in the axial and radial configurations are different but their growth rates are comparable. We found that the radial configuration can have a beam impedance less than 10 {Omega} and therefore more suitable for low-voltage and high power operation. Good agreements have been obtained between linear theory and simulation for both configurations.
The nonclassical effects in coupled optomechanical array
Zhou, Wenjun; Cheng, Jiong; Zhang, Wenzhao; Yousif, Taha; Zhou, Ling
2015-07-01
We investigate a coupled array of ? identical cavity optomechanical systems. By adiabatically eliminating the cavity fields, we derive an effective Hamiltonian of the ? phonon modes coupled via XX form. We show further that the coupled mechanical oscillators can be used to transmit state and the single mode of the oscillator and the two-mode of neighbor oscillators can exhibit squeezing simultaneously. Under the suitable regime of parameters, the phonon blockade is exhibited.
Break-up effects of 19F projectile at ≈ 4-6 MeV/A
International Nuclear Information System (INIS)
In the present work analysis of excitation functions (EFs) has been used to deduce the energy dependence of ICF strength function and to study the effect of Qα-values and that of mass asymmetry. To explore the influence of ICF on CF in 19F + 159Tb reactions in the energy range ≈ 80-110 MeV, an off-line γ-ray spectroscopy technique has been employed. The present results have been compared with the existing data of 12,13C + 159Tb, and 16O + 159Tb systems
Investigation on Electrostatical Breakup of Bio-Oil Droplets
Directory of Open Access Journals (Sweden)
John Z. Wen
2012-10-01
Full Text Available In electrostatic atomization, the input electrical energy causes breaking up of the droplet surface by utilizing a mutual repulsion of net charges accumulating on that surface. In this work a number of key parameters controlling the bio-oil droplet breakup process are identified and these correlations among the droplet size distribution, specific charges of droplets and externally applied electrical voltages are quantified. Theoretical considerations of the bag or strip breakup mechanism of biodiesel droplets experiencing electrostatic potential are compared to experimental outcomes. The theoretical analysis suggests the droplet breakup process is governed by the Rayleigh instability condition, which reveals the effects of droplets size, specific charge, surface tension force, and droplet velocities. Experiments confirm that the average droplet diameters decrease with increasing specific charges and this decreasing tendency is non-monotonic due to the motion of satellite drops in the non-uniform electrical field. The measured specific charges are found to be smaller than the theoretical values. And the energy transformation from the electrical energy to surface energy, in addition to the energy loss, Taylor instability breakup, non-excess polarization and some system errors, accounts for this discrepancy. The electrostatic force is the dominant factor controlling the mechanism of biodiesel breakup in electrostatic atomization.
Elastic and break-up of the 1n-halo 11Be nucleus
Di Pietro, A.; Moro, A. M.; Acosta, L.; Amorini, F.; Borge, M. J. G.; Figuera, P.; Fisichella, M.; Fraile, L. M.; Gomez-Camacho, J.; Jeppesen, H.; Lattuada, M.; Martel, I.; Milin, M.; Musumarra, A.; Papa, M.; Pellegriti, M. G.; Perez-Bernal, F.; Raabe, R.; Randisi, G.; Rizzo, F.; Scuderi, V.; Tengblad, O.; Torresi, D.; Vidal, A. Maira; Voulot, D.; Wenander, F.; Zadro, M.
2014-03-01
The elastic and break-up angular distributions of the 10,11Be+64Zn reactions measured at Ec.m.≈1.4 VC have been analysed within the CCDC and O.M. frameworks. The suppression of the Coulomb-nuclear interference, observed in the 11Be scattering case with respect to the 10Be, has been interpreted as due to a long range absorption owing to the coupling with the break-up (Coulomb and nuclear) channels. The presence of 10Be events on the 11Be experiment data have been explained as due mainly to break-up processes.
Elastic and break-up of the 1n-halo 11Be nucleus
Directory of Open Access Journals (Sweden)
Di Pietro A.
2014-03-01
Full Text Available The elastic and break-up angular distributions of the 10,11Be+64Zn reactions measured at Ec.m.≈1.4 VC have been analysed within the CCDC and O.M. frameworks. The suppression of the Coulomb-nuclear interference, observed in the 11Be scattering case with respect to the 10Be, has been interpreted as due to a long range absorption owing to the coupling with the break-up (Coulomb and nuclear channels. The presence of 10Be events on the 11Be experiment data have been explained as due mainly to break-up processes.
Lei, Jin
2015-01-01
The problem of the calculation of inclusive breakup cross sections in nuclear reactions is reexamined. For that purpose, the post-form theory proposed by Ichimura, Austern and Vincent [Phys. Rev. C32, 431 (1985) is revisited, and an alternative derivation of the non-elastic breakup part of the inclusive breakup is presented, making use of the coupled-channels optical theorem. Using the DWBA version of this model, several applications to deuteron and $^6$Li reactions are presented and compared with available data. The validity of the zero-range approximation of the DWBA formula is also investigated by comparing zero-range with full finite-range calculations.
Semiclassical treatment of fusion and breakup processes of ^{6,8}He halo nuclei
Majeed, Fouad A.; Abdul-Hussien, Yousif A.
2016-06-01
A semiclassical approach has been used to study the effect of channel coupling on the calculations of the total fusion reaction cross section σ _{fus}, and the fusion barrier distribution D_{fus} for the systems 6He +^{238}U and 8He +^{197}Au. Since these systems invloves light exotic nuclei, breakup states channel play an important role that should be considered in the calculations. In semiclassical treatment, the relative motion between the projectile and target nuclei is approximated by a classical trajectory while the intrinsic dynamics is handled by time-dependent quantum mechanics. The calculations of the total fusion cross section σ _{fus}, and the fusion barrier distribution D_{fus} are compared with the full quantum mechanical calculations using the coupled-channels calculations with all order coupling using the computer code and with the available experimental data.
Elastic Coulomb breakup of 34Na
Singh, G.; Shubhchintak, Chatterjee, R.
2016-08-01
Background: 34Na is conjectured to play an important role in the production of seed nuclei in the alternate r -process paths involving light neutron rich nuclei very near the β -stability line, and as such, it is important to know its ground state properties and structure to calculate rates of the reactions it might be involved in, in the stellar plasma. Found in the region of `island of inversion', its ground state might not be in agreement with normal shell model predictions. Purpose: The aim of this paper is to study the elastic Coulomb breakup of 34Na on 208Pb to give us a core of 33Na with a neutron and in the process we try and investigate the one neutron separation energy and the ground state configuration of 34Na. Method: A fully quantum mechanical Coulomb breakup theory within the architecture of post-form finite range distorted wave Born approximation extended to include the effects of deformation is used to research the elastic Coulomb breakup of 34Na on 208Pb at 100 MeV/u. The triple differential cross section calculated for the breakup is integrated over the desired components to find the total cross-section, momentum, and angular distributions as well as the average momenta, along with the energy-angular distributions. Results: The total one neutron removal cross section is calculated to test the possible ground state configurations of 34Na. The average momentum results along with energy-angular calculations indicate 34Na to have a halo structure. The parallel momentum distributions with narrow full widths at half-maxima signify the same. Conclusion: We have attempted to analyze the possible ground state configurations of 34Na and in congruity with the patterns in the `island of inversion' conclude that even without deformation, 34Na should be a neutron halo with a predominant contribution to its ground state most probably coming from 33Na(3 /2+)⊗ 2 p3 /2ν configuration. We also surmise that it would certainly be useful and rewarding to test our
Laser-induced break-up of water jet waveguide
Energy Technology Data Exchange (ETDEWEB)
Couty, P.; Hoffmann, P. [EPFL/STI/IOA/Advanced Photonics Laboratory, Lausanne BM, 1015, Lausanne (Switzerland); Spiegel, A.; Vago, N. [Department of Atomic Physics, Budapest University of Technology and Economics, Budafoki ut 8, 1111, Budapest (Hungary); Ugurtas, B.I. [EPFL/STI/IMHEF/Laboratory Fluid Mechanics, Lausanne, 1015, Lausanne (Switzerland)
2004-06-01
In this article, an optical method to control the break-up of high-speed liquid jets is proposed. The method consists of focusing the light of a pulsed laser source into the jet behaving as a waveguide. Experiments were performed with the help of a Q-switched frequency doubled Nd:Yag laser ({lambda}=532 nm). The jet diameter was 48 {mu}m and jet velocities from 100 to 200 m/s. To study the laser-induced water jet break-up, observations of the jet coupled with the high power laser were performed for variable coupling and jet velocity conditions. Experimentally determined wavelength and growth rate of the laser-generated disturbance were also compared with the ones predicted by linear stability theory of free jets. (orig.)
Deuteron–deuteron scattering above four-nucleon breakup threshold
Directory of Open Access Journals (Sweden)
A. Deltuva
2015-03-01
Full Text Available Deuteron–deuteron elastic scattering and transfer reactions in the energy regime above four-nucleon breakup threshold are described by solving exact four-particle equations for transition operators. Several realistic nuclear interaction models are used, including the one with effective many-nucleon forces generated by the explicit Δ-isobar excitation; the Coulomb force between protons is taken into account as well. Differential cross sections, deuteron analyzing powers, outgoing nucleon polarization, and deuteron-to-neutron polarization transfer coefficients are calculated at 10 MeV deuteron energy. Overall good agreement with the experimental data is found. The importance of breakup channels is demonstrated.
Effective Multi-Higgs Couplings to Gluons
Spira, Michael
2016-01-01
Standard-Model Higgs bosons are dominantly produced via the gluon-fusion mechanism $gg \\to H$ at the LHC, i.e. in a loop-mediated process with top loops providing the dominant contribution. For the measured Higgs boson mass of $\\sim 125$ GeV the limit of heavy top quarks provides a reliable approximation as long as the relative QCD corrections are scaled with the full mass-dependent LO cross section. In this limit the Higgs coupling to gluons can be described by an effective Lagrangian. The same approach can also be applied to the coupling of more than one Higgs boson to gluons. We will derive the effective Lagrangian for multi-Higgs couplings to gluons up to N$^4$LO thus extending previous results for more than one Higgs boson. Moreover we discuss gluonic Higgs couplings up to NNLO, if several heavy quarks contribute.
Tensor coupling effect on relativistic symmetries
Chen, ShouWan; Li, DongPeng; Guo, JianYou
2016-08-01
The similarity renormalization group is used to transform the Dirac Hamiltonian with tensor coupling into a diagonal form. The upper (lower) diagonal element becomes a Schr¨odinger-like operator with the tensor component separated from the original Hamiltonian. Based on the operator, the tensor effect of the relativistic symmetries is explored with a focus on the single-particle energy contributed by the tensor coupling. The results show that the tensor coupling destroying (improving) the spin (pseudospin) symmetry is mainly attributed to the coupling of the spin-orbit and the tensor term, which plays an opposite role in the single-particle energy for the (pseudo-) spin-aligned and spin-unaligned states and has an important influence on the shell structure and its evolution.
Coupling effects in multiphase free shear flows
International Nuclear Information System (INIS)
The primary goal of this research program is to examine the effects of two-way multiphase coupling on the development of organized vortex structures in free shear flows and the resultant multiphase dispersion. Previous research studies have determined that one-way coupled particle dispersion in free shear flows is strongly dependent on the vortex structures present in these flows and their interactions as well as the ratio of the particle aerodynamic response time to the time scale of the dominant vortex structures. Current research efforts are directed towards exploring the effects that two-way momentum, mass and energy coupling have on the multiphase dispersion processes previously uncovered. These efforts involve analytical, numerical and experimental investigations. Recent analytical and numerical results indicate that momentum coupling effects can significantly alter the global stability and potentially the large scale features of the multiphase flow field. These multiphase coupling effects may have significant importance with regard to predicting the performance of many energy conversion systems
The breakup of levitating water drops observed with a high speed camera
Directory of Open Access Journals (Sweden)
C. Emersic
2011-10-01
Full Text Available Collision-induced water drop breakup in a vertical wind tunnel was observed using a high speed camera for interactions between larger drop sizes (up to 7 mm diameter than have previously been experimentally observed. Three distinct collisional breakup types were observed and the drop size distributions from each were analysed for comparison with predictions of fragment distributions from larger drops by two sets of established breakup parameterisations. The observations showed some similarities with both parameterisations but also some marked differences for the breakup types that could be compared, particularly for fragments 1 mm and smaller. Modifications to the parameterisations are suggested and examined. Presented is also currently the largest dataset of bag breakup distributions observed. Differences between this and other experimental research studies and modelling parameterisations, and the associated implications for interpreting results are discussed. Additionally, the stochastic coalescence and breakup equation was solved computationally using a breakup parameterisation, and the evolving drop-size distribution for a range of initial conditions was examined. Initial cloud liquid water content was found to have the greatest influence on the resulting distribution, whereas initial drop number was found to have relatively little influence. This may have implications when considering the effect of aerosol on cloud evolution, raindrop formation and resulting drop size distributions. Calculations presented show that, using an ideal initial cloud drop-size distribution, ~1–3% of the total fragments are contributed from collisional breakup between drops of 4 and 6 mm.
Experimental research on breakup of 2D power law liquid film☆
Institute of Scientific and Technical Information of China (English)
Lixing Xu; Zhenyan Xia; Mengzheng Zhang; Qing Du; Fuqiang Bai
2015-01-01
On account of limited knowledge of the breakup of power law liquid film, the process of its disintegration and atomization was studied by using a planar liquid film. A linear stability analysis was adopted to predict the breakup characteristics of the power law film. The predicting formulas of stripping breakup length and diameter of ligament were put forward presently. Through high-speed photography and laser light sheet illumination, different breakup characteristics of flat power law film under different conditions were derived. The characteristic dimension of breakup regimes were defined and extracted. The effects of several parameters (injection pressure, ambient pressure, nozzle structure and fluid property) on the stripping breakup length and spray angle were investigated. The results revealed that increasing both the velocity of liquid film and the ambient pressure facilitated the breakup of film, reduced the stripping breakup length and enlarged the spray angle in different extents. The comparison between theoretical and experimental results was conducted to validate the feasibility of the linear stability theory.
Instability and breakup of cavitation bubbles within diesel drops
Institute of Scientific and Technical Information of China (English)
Ming Lü; Zhi Ning; Kai Yan; Juan Fu; Chunhua Sun
2015-01-01
A modified mathematical model is used to study the effects of various forces on the stability of cavitation bubbles within a diesel droplet. The principal finding of the work is that viscous forces of fluids stabilize the cavitation bubble, while inertial force destabilizes the cavitation bubble. The droplet viscosity plays a dominant role on the stability of cavitation bubbles compared with that of air and bubble. Bubble–droplet radius ratio is a key factor to control the bubble stability, especially in the high radius ratio range. Internal hydrodynamic and surface tension forces are found to stabilize the cavitation bubble, while bubble stability has little relationship with the external hydrodynamic force. Inertia makes bubble breakup easily, however, the breakup time is only slightly changed when bubble growth speed reaches a certain value (50 m·s−1). In contrast, viscous force makes bubble hard to break. With the increasing initial bubble–droplet radius ratio, the bubble growth rate increases, the bubble breakup radius decreases, and the bubble breakup time becomes shorter.
Structural Stability of the Coalescence/Breakup Equation.
Brown, Philip S., Jr.
1995-11-01
An analysis of the structural stability of the coalescence/breakup equation is performed to determine the degree to which changes in the equation's formulation can affect the solution. The work was motivated by speculation in various quarters that the currently used coalescence/breakup formulation should be adjusted to achieve better agreement between solutions and field observations. Both analytical procedures and numerical experiments, in which hypothetical changes in the rate coefficients are assumed, show the coalescence/breakup equation in its current formulation to be structurally stable. Not only do small changes in the rate coefficients produce negligible change in the solutions, but even large changes in the rate coefficients fail to destroy the fundamental behavior of the system in that all solutions continue to approach a unique equilibrium. Moderate-sized perturbations of the coefficients are found to have only minor influence on the solutions unless the coalescence and breakup efficiencies, constituents of the rate coefficients, are perturbed in an opposite sense to reinforce the individual effects. Only with such changes in the formulation is the equilibrium solution found to be altered to a significant degree.
Directory of Open Access Journals (Sweden)
S. Jafarmadar
2014-01-01
Full Text Available This paper proposes a new unified single model that considers droplet break-up and air entrainment impact on three flow regimes (namely, Stokes, Allen, and Newton in the initial stage of fuel spray penetration. Homotopy perturbation method was used to obtain semianalytical solutions of unified single model on diesel fuel’s spray penetration when the influence of air entrainment is small (up to 0.1-0.2 ms after the start of injection. It is demonstrated that the applied analytical method is very straightforward in comparison with existing techniques. Furthermore, it is decidedly effectual in terms of accuracy and rapid convergence. The formulation of the problem is presented in the text as well as the analytical and numerical procedures.
Cooperative Effects of Noise and Coupling on Stochastic Dynamics of a Membrane-Bulk Coupling Model
Institute of Scientific and Technical Information of China (English)
TANG Jun; JIA Ya; YI Ming
2009-01-01
Based on a membrane-bulk coupling cell model proposed by Gomez-Marin et al. [ Phys. Rev. Lett. 98 (2007) 168303], the cooperative effects of noise and coupling on the stochastic dynamical behavior are investigated, For parameters in a certain region, the oscillation can be induced by the cooperative effect of noise and coupling. Whether considering the coupling or not, corresponding coherence resonance phenomena are observed. Furthermore, the effects of two coupling parameters, cell size L and coupling intensity k, on the noise-induced oscillation of membranes are studied. Contrary effects of noise are found in and out of the deterministic oscillatory regions.
Considerations and calculations on the breakup of jets and drops of melt related to premixing
Energy Technology Data Exchange (ETDEWEB)
Buerger, M.; Berg, E. von; Buck, M. [Inst. fuer Kernenergetik und Energiesysteme (IKE), Univ. of Stuttgart, Pfaffenwaldring 31, 70569 Stuttgart (Germany)
1998-01-01
Various descriptions of jet and drop breakup are applied in premixing codes, presently. The main task is to check these descriptions over a wide range of conditions in order to assure extrapolation capabilities for the codes. Jet breakup under non-boiling conditions is relatively well described by IKEJET, based on Conte/Miles (CM) instability description and a relatively detailed stripping model, in contrast to using Kelvin/Helmholtz (KH) theory. Remaining open questions are elaborated. Especially, thick jet behavior with dominance of stripping even at small relative velocities must be distinguished from thin jets with coarse breakup. The application of IKEJET to cases with jet breakup under strong film boiling yielded significantly too little fragmentation. As a possible explanation line, multiphase effects on the wave growth and stripping are considered, due to entrainment of melt and water. Parametric checking calculations are performed with a strongly simplified approach for PREMIX and FARO experiments in order to reveal main effects and the possible physical explanation features as a basis for extended modelling. The results indicate that jet breakup may be essentially sufficient to explain the experimental behavior. Rather coalescence than further drop breakup may be expected. This is also indicated by calculations with IKE drop breakup models. (author)
Transfer to the continuum and Breakup reactions
Moro, A M
2006-01-01
A standard approach for the calculation of breakup reactions of exotic nuclei into two fragments is to consider inelastic excitations into the single particle continuum of the projectile. Alternatively one can also consider the transfer to the continuum of a system composed of the light fragment and the target. In this work we make a comparative study of the two approaches, underline the different inputs, and identify the advantages and disadvantages of each approach. Our test cases consist of the breakup of $^{11}$Be on a proton target at intermediate energies, and the breakup of $^8$B on $^{58}$Ni at energies around the Coulomb barrier.
COUPLED ATOMIZATION AND SPRAY MODELLING IN THE SPRAY FORMING PROCESS USING OPENFOAM
DEFF Research Database (Denmark)
Gjesing, Rasmus; Hattel, Jesper Henri; Fritsching, Udo
2009-01-01
The paper presents a numerical model capable of simulating the atomization, break-up and in-flight spray phenomena in the spray forming process. The model is developed and implemented in the freeware code openFOAM. The focus is on studying the coupling effect of the melt break-up phenomena with the...... model for droplet cooling and solidification. The model is tested and validated against results from literature and experiments. Subsequently, the model is used to simulate the complex flow fields in the spray forming process and the results are discussed. The presented model of the spray forming...... process is able to predict the droplet size distribution of the spray from the process conditions, by introducing submodels for the melt fragmentation and successive secondary break-up processes as part of the spray model. Furthermore, the competition of drop break-up and solidification is derived by...
Negative Emotions and Behaviors are Markers of Breakup Distress
Field, Tiffany; Diego, Miguel; Pelaez, Martha; Deeds, Osvelia; Delgado, Jeanette
2013-01-01
Method: University students who experienced a recent romantic breakup were given several self-report measures and were then divided into high versus low breakup distress groups. Results: The high breakup distress versus the low breakup distress groups had higher scores on negative emotions scales including depression, anxiety and anger and…
Intrusive Thoughts: A Primary Variable in Breakup Distress
Field, Tiffany; Diego, Miguel; Pelaez, Martha; Deeds, Osvelia; Delgado, Jeannette
2013-01-01
University students who were high versus low on breakup distress scores were given self-report measures to assess their intrusive thoughts about the romantic breakup and their somatic symptoms that followed the breakup as well as their extracurricular activities and social support that might alleviate their breakup distress. In a regression…
Breakup of spherical vesicles caused by spontaneous curvature change
Institute of Scientific and Technical Information of China (English)
Ping Liu; Ju Li; Yong-Wei Zhang
2012-01-01
We present our theoretical analysis and coarsegrained molecular dynamics (CGMD) simulation results to describe the mechanics of breakup of spherical vesicles driven by changes in spontaneous curvature.Systematic CGMD simulations reveal the phase diagrams for the breakup and show richness in breakup morphologies.A theoretical model based on Griffith fracture mechanics is developed and used to predict the breakup condition.
Experimental and simulated d p breakup reaction data at 300, 400 and 500 MeV
Directory of Open Access Journals (Sweden)
Janek M.
2014-01-01
Full Text Available d p breakup reaction occupies large phase space. Two and three nucleon forces and relativistic effects can be investigated under various detector configuration. The results of simulation of d p breakup reaction in energy region from 300 to 500 MeV are presented. Preliminary results obtained at 300, 400 and 500 MeV of deuteron energy at some detector configurations at Nuclotron as well as future plans in investigation of relativistic effects are discussed.
Fermi breakup and the statistical multifragmentation model
Energy Technology Data Exchange (ETDEWEB)
Carlson, B.V., E-mail: brett@ita.br [Departamento de Fisica, Instituto Tecnologico de Aeronautica - CTA, 12228-900 Sao Jose dos Campos (Brazil); Donangelo, R. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Cidade Universitaria, CP 68528, 21941-972, Rio de Janeiro (Brazil); Instituto de Fisica, Facultad de Ingenieria, Universidad de la Republica, Julio Herrera y Reissig 565, 11.300 Montevideo (Uruguay); Souza, S.R. [Instituto de Fisica, Universidade Federal do Rio de Janeiro, Cidade Universitaria, CP 68528, 21941-972, Rio de Janeiro (Brazil); Instituto de Fisica, Universidade Federal do Rio Grande do Sul, Av. Bento Goncalves 9500, CP 15051, 91501-970, Porto Alegre (Brazil); Lynch, W.G.; Steiner, A.W.; Tsang, M.B. [Joint Institute for Nuclear Astrophysics, National Superconducting Cyclotron Laboratory and the Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824 (United States)
2012-02-15
We demonstrate the equivalence of a generalized Fermi breakup model, in which densities of excited states are taken into account, to the microcanonical statistical multifragmentation model used to describe the disintegration of highly excited fragments of nuclear reactions. We argue that such a model better fulfills the hypothesis of statistical equilibrium than the Fermi breakup model generally used to describe statistical disintegration of light mass nuclei.
Breakup characteristics of a liquid jet in subsonic crossflow
Gopala, Yogish
This thesis describes an experimental investigation of the breakup processes involved in the formation of a spray created by a liquid jet injected into a gaseous crossflow. This work is motivated by the utilization of this method to inject fuel in combustors and afterburners of airplane engines. This study aims to develop a better understanding of the spray breakup processes and to provide better experimental inputs to improve the fidelity of numerical models. A review of the literature in this field identified the fundamental physical processes involved in the breakup of the spray and the dependence of spray properties on operating conditions. The time taken for the liquid column to break up into ligaments and droplets, the primary breakup time and the effect of injector geometry on the spray formation processes and spray properties as the key research areas in which research done so far has been inadequate. Determination of the location where the liquid column broke up was made difficult by the presence of a large number of droplets surrounding it. This study utilizes the liquid jet light guiding technique that enables accurate measurements of this location for a wide range of operating conditions. Prior to this study, the primary breakup time was thought to be a function the density ratio of the liquid and the gas, the diameter of the orifice and the air velocity. This study found that the time to breakup of the liquid column depends on the Reynolds number of the liquid jet. This suggests that the breakup of a turbulent liquid jet is influenced by both the aerodynamic breakup processes and the turbulent breakup processes. Observations of the phenomenon of the liquid jet splitting up into two or more jets were made at some operating conditions with the aid of the new visualization technique. Finally, this thesis investigates the effect of injector geometry on spray characteristics. One injector was a round edged orifice with a length to diameter ratio of 1 and a
Edge Effects and Coupling Effects in Atomic Force Microscope Images
Institute of Scientific and Technical Information of China (English)
ZHANGXiang-jun; MENGYong-gang; WENShi-zhu
2004-01-01
The AFM images were obtained by an atomic force microscope (AFM) and transformed from the deformation of AFM micro cantilever probe. However, due to the surface topography and surface forces applied on the AFM tip of sample, the deformation of AFM probe results in obvious edge effects and coupling effects in the AFM images. The deformation of AFM probe was analyzed,the mechanism of the edge effects and the coupling effects was investigated, and their results in the AFM images were studied. It is demanstrated by the theoretical analysis and AFM experiments that the edge effects make lateral force images more clear than the topography images, also make extraction of frictional force force from lateral force images mare complex and difficult. While the coupling effects make the comparison between topography images and lateral force images mare advantage to acquire precise topography information by AFM.
Coupling Effect of Ion Channel Clusters on Calcium Signalling
International Nuclear Information System (INIS)
Based on a modified intracellular Ca2+ model involving diffusive coupling of two calcium ion channel clusters, the effects of coupling on calcium signalling are numerically investigated. The simulation results indicate that the diffusive coupling of clusters together with internal noise determine the calcium dynamics of single cluster, and for either homogeneous or heterogeneous coupled clusters, the synchronization of clusters, which is important to calcium signalling, is enhanced by the coupling effect
Coupling Effect of Ion Channel Clusters on Calcium Signalling
Institute of Scientific and Technical Information of China (English)
TANG Jun; JIA Ya; YI Ming; MA Jun; YU Guang
2008-01-01
@@ Based on a modified intracellular Ca2+ model involving diffusive coupling of two calcium ion channel clusters,the effects of coupling on calcium signalling are numerically investigated.The simulation results indicate that the diffusive coupling of clusters together with internal noise determine the calcium dynamics of single cluster,and for either homogeneous or heterogeneous coupled clusters,the synchronization of clusters,which is important to calcium signalling,is enhanced by the coupling effect.
Strong coupling effective theory with heavy fermions
Fromm, Michael; Lottini, Stefano; Philipsen, Owe
2011-01-01
We extend the recently developed strong coupling, dimensionally reduced Polyakov-loop effective theory from finite-temperature pure Yang-Mills to include heavy fermions and nonzero chemical potential by means of a hopping parameter expansion. Numerical simulation is employed to investigate the weakening of the deconfinement transition as a function of the quark mass. The tractability of the sign problem in this model is exploited to locate the critical surface in the (M/T, mu/T, T) space over the whole range of chemical potentials from zero up to infinity.
Longitudinal coupling effect in microfiber Bragg gratings
Zhao, Ping; Zhang, Jihua; Wang, Guanghui; Jiang, Meng; Ping Shum, Perry; Zhang, Xinliang
2012-10-01
We theoretically present longitudinal coupling effect (LCE) in air-cladding microfiber Bragg gratings (MFBGs). Distinct from conventional weakly-guiding optical fibers, large longitudinal electric field (Ez) exists in wavelength-scale microfibers. Due to LCE, MFBG reflectivity can be reduced by more than 30% within the band-gap and the full width at half maximum (FWHM) is obviously narrowed. This theoretical analytical work is instructive to precisely design and fabricate MFBGs that are promising in the areas of optical sensing and nanophotonics.
Inverted Break-up Behaviour in Continuous Inkjet (CIJ) Printing
McIlroy, Claire; Harlen, Oliver; Morrison, Neil
2014-11-01
Although droplet creation during continuous jetting of Newtonian fluids has been widely studied, unsolved problems surrounding the break-up dynamics remain. Jetting through a nozzle creates a stream of liquid that is rendered unstable by surface tension. This instability creates a succession of main drops connected by thin filaments, with drop separation determined by the fastest growing wavelength. In order to control break-up and increase printing speeds, continuous inkjet (CIJ) printing exploits the effects of finite amplitude modulations in the jet velocity profile giving conditions where jet stability deviates from the usual Rayleigh behaviour. To explore these non-linear effects, we have developed a one-dimensional jetting model. In particular, we identify a modulation range for which pinching occurs upstream of the connecting filament, rather than downstream - a phenomenon we call ``inverted'' break-up. Furthermore, this behaviour can be controlled by the addition of harmonics to the initial driving signal. Our results are compared to full axisymmetric simulations in order to incorporate the effects of nozzle geometry. EPSRC Innovation in Industrial Technology.
Dynamic nonlinear thermal optical effects in coupled ring resonators
Directory of Open Access Journals (Sweden)
Chenguang Huang
2012-09-01
Full Text Available We investigate the dynamic nonlinear thermal optical effects in a photonic system of two coupled ring resonators. A bus waveguide is used to couple light in and out of one of the coupled resonators. Based on the coupling from the bus to the resonator, the coupling between the resonators and the intrinsic loss of each individual resonator, the system transmission spectrum can be classified by three different categories: coupled-resonator-induced absorption, coupled-resonator-induced transparency and over coupled resonance splitting. Dynamic thermal optical effects due to linear absorption have been analyzed for each category as a function of the input power. The heat power in each resonator determines the thermal dynamics in this coupled resonator system. Multiple “shark fins” and power competition between resonators can be foreseen. Also, the nonlinear absorption induced thermal effects have been discussed.
Dynamical diagnosis of the breakup of the stratospheric polar vortex in the Northern Hemisphere
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
The research on climate change in polar regions, especially on the role of polar in the global climate system, has gain unprecedented level of interest. It has been the key scientific issue of the International Polar Year program (IPY, 2007―2008). In this paper, we dealt with the debate upon the breakup time of the stratospheric polar vortex in boreal spring. An observational study of the relation between stratospheric polar vortex breakup and the extra-tropical circulation was performed. The mean breakup date―when the winter westerly at the core of polar jet turns to summer easterly―is about April 10. The breakup time has large interannual variation with a time span of about 2 months. It also has a long-term trend with the 1990s and 2000s witnessing more and more late breakups of polar vortex. Composite of wind speed at the core of polar jet for the extremely early and late breakup years shows that late years have two periods of westerly weakening while early breakup years have only one. The first weakening in the late years happens in middle January with wind speed dropping sharply from more than 40 m s-1 to about 15 m s-1. This is accompanied with anomalous activities of planetary waves in both stratosphere and troposphere; while the second weakening in the late breaking years is mainly the results of diabatic heating with very weak wave activities. In early breakup years, the transition from westerly to easterly is rapid with wind speed dropping from more than 30 m s-1 to less than -10 m s-1 within a month. This evolution is associated with a strong bidirectional dynamical coupling of the stratosphere and troposphere. The circulation anomalies at low troposphere are also analyzed in the extremely early and late breakup years. It shows that there are significant differences between the two kinds of extreme years in the geopotential height and temperature composite analysis, indicating the dynamical coupling of stratosphere and troposphere with the
Some features of spray breakup in effervescent atomizers
Energy Technology Data Exchange (ETDEWEB)
Gadgil, Hrishikesh P.; Raghunandan, B.N. [Indian Institute of Science, Department of Aerospace Engineering, Bangalore (India)
2011-02-15
The near orifice spray breakup at low GLR (gas to liquid ratio by mass) values in an effervescent atomizer is studied experimentally using water as a simulant and air as atomizing gas. From the visualizations, the near orifice spray structures are classified into three modes: discrete bubble explosions, continuous bubble explosions and annular conical spray. The breakup of the spray is quantified in terms of the mean bubble bursting distance from the orifice. The parametric study indicates that the mean bubble bursting distance mainly depends on airflow rate, jet diameter and mixture velocity. It is also observed that the jet diameter has a dominant effect on the bubble bursting distance when compared to mixture velocity at a given airflow rate. The mean bubble bursting distance is shown to be governed by a nondimensional two-phase flow number consisting of all the aforementioned parameters. The location of bubble bursting is found to be highly unsteady spatially, which is influenced by flow dynamics inside the injector. It is proposed that this unsteadiness in jet breakup length is a consequence of varying degree of bubble expansion caused due to the intermittent occurrence of single phase and two-phase flow inside the orifice. (orig.)
Nonlinear dynamics and breakup of free-surface flows
International Nuclear Information System (INIS)
Surface-tension-driven flows and, in particular, their tendency to decay spontaneously into drops have long fascinated naturalists, the earliest systematic experiments dating back to the beginning of the 19th century. Linear stability theory governs the onset of breakup and was developed by Rayleigh, Plateau, and Maxwell. However, only recently has attention turned to the nonlinear behavior in the vicinity of the singular point where a drop separates. The increased attention is due to a number of recent and increasingly refined experiments, as well as to a host of technological applications, ranging from printing to mixing and fiber spinning. The description of drop separation becomes possible because jet motion turns out to be effectively governed by one-dimensional equations, which still contain most of the richness of the original dynamics. In addition, an attraction for physicists lies in the fact that the separation singularity is governed by universal scaling laws, which constitute an asymptotic solution of the Navier-Stokes equation before and after breakup. The Navier-Stokes equation is thus continued uniquely through the singularity. At high viscosities, a series of noise-driven instabilities has been observed, which are a nested superposition of singularities of the same universal form. At low viscosities, there is rich scaling behavior in addition to aesthetically pleasing breakup patterns driven by capillary waves. The author reviews the theoretical development of this field alongside recent experimental work, and outlines unsolved problems. copyright 1997 The American Physical Society
Quark and pion effective couplings from polarization effects
Energy Technology Data Exchange (ETDEWEB)
Braghin, Fabio L. [Federal University of Goias, Instituto de Fisica, Goiania, GO (Brazil)
2016-05-15
A flavor SU(2) effective model for pions and quarks is derived by considering polarization effects departing from the usual quark-quark effective interaction induced by dressed gluon exchange, i.e. a global color model for QCD. For that, the quark field is decomposed into a component that yields light mesons and the quark-antiquark condensate, being integrated out by means of the auxiliary field method, and another component which yields constituent quarks, which is basically a background quark field. Within a long-wavelength and weak quark field expansion (or large quark effective mass expansion) of a quark determinant, the leading terms are found up to the second order in a zero-order derivative expansion, by neglecting vector mesons that are considerably heavier than the pion. Pions are considered in the structureless limit and, besides the chiral invariant terms that reproduce previously derived expressions, symmetry breaking terms are also presented. The leading chiral quark-quark effective couplings are also found corresponding to a NJL and a vector-NJL couplings. All the resulting effective coupling constants and parameters are expressed in terms of the current and constituent quark masses and of the coupling g. (orig.)
QCD Effective Coupling in the Infrared Region
Ganbold, Gurjav
2010-01-01
We estimate the QCD effective charge $\\alpha_s$ in the low-energy region by exploiting the conventional meson spectrum within a relativistic quantum-field model based on analytic confinement. The ladder Bethe-Salpeter equation is solved for the masses of two-quark bound states. We found a new, independent and specific infrared-finite behavior of QCD coupling below energy scale 1 GeV. Particularly, an infrared-fixed point is extracted at $\\alpha_s(0)\\simeq 0.757$ for confinement scale $\\Lambda=345$ MeV. As an application, we estimate masses of some intermediate and heavy mesons and obtain results in reasonable agreement with recent experimental data.
Directory of Open Access Journals (Sweden)
Aguilar AJ
2014-11-01
Full Text Available Alejandro J Aguilar, Maria I Marquez, Paula A Albera, Jorge L Tredicce, Alejandro Berra Universidad de Buenos Aires, Buenos Aires, Argentina Purpose: To evaluate the ability of Systane® Balance (SYSB administered four times per day for 4 weeks to increase noninvasive tear film break-up time (NITFBUT over baseline compared with a saline (SAL control in patients with lipid-deficient dry eye (DE.Patients and methods: Patients aged ≥18 years with DE and evidence of meibomian gland dysfunction (ie, abnormal gland expression and missing meibomian glands were included in this randomized, parallel-group, controlled, investigator-masked comparison study. Patients were randomized to SYSB or SAL four times daily for 4 weeks. The primary efficacy variable was mean change in NITFBUT from baseline at week 4. Ocular surface staining, goblet cell density, and meibomian gland expression were also assessed. Safety assessments included adverse events (AEs, best-corrected visual acuity, and ocular signs.Results: A total of 49 patients received study treatments (SYSB, n=25; SAL, n=24. Most patients were women (67.4% and Caucasian (63.3%; mean ± standard deviation (SD age was 44±19 years. DE characteristics at baseline were similar between groups. After 4 weeks of treatment, the mean ± SD NITFBUT increase from baseline was significantly greater with SYSB (2.83±0.74 seconds compared with SAL (0.66±0.55 seconds; P<0.001, t-test. Improvements in conjunctival and corneal staining, percentage of patients with increased goblet cell density, and meibomian gland expression were also observed with 4 weeks of SYSB over SAL. No AEs were reported for either treatment group; best-corrected visual acuity and ocular signs remained stable or improved compared with baseline.Conclusion: SYSB restored tear film stability, improved ocular surface healing, and improved meibomian gland functionality after 4 weeks of use in patients with lipid-deficient DE. No AEs were reported
The Davie Ridge: a Marginal Transform Ridge not Formed During Continental Breakup
Phethean, J. J. J.; Van Hunen, J.; McCaffrey, K. J. W.; Davies, R. J.
2014-12-01
The breakup of Gondwana translated Madagascar southwards relative to Africa along the Davie Fracture Zone (DFZ). This fracture zone now forms the Transform Passive Continental Margin (TPCM) from Kenya to Mozambique. The Davie Ridge (DR), a transform marginal ridge, has formed along the DFZ between 5 and 2°S and 22 and 11°S, but with little expression in-between. It has been proposed that this marginal ridge was formed by the thermal effects of a passing Mid Ocean Ridge (MOR) during the separation of Gondwana. Plate kinematic reconstructions, however, constrained by ocean magnetic anomalies, show that the MOR only passed between the north and south expressions of the DR. Therefore the positive linear gravity anomalies of the DR cannot be attributed to the effects of a passing MOR, and some other mechanism must be found to explain their formation. Interpretation of seismic reflection profiles along the DR shows that the gravity highs occur adjacent to large basin structures. In the north this correlates with a basin-bounding basement high of ~Albian age, and in the south with the rift flank uplifts of the currently active Quirimbas graben. This suggests that the northern and southern DR segments are instead shoulder uplifts resulting from two separate extensional episodes during different stress regimes. These are the Cretaceous NE-SW extension during the breakup of the south Atlantic, and the E-W extension of the Neogene-recent Afar-East Africa rift system, respectfully. The lack of deformation and DR formation along the region of the TPCM passed by the MOR suggests it has been coupled by thermal effects and/or the injection of magma.
Ng, Chee-Loon
Scope and method of study. An experimental and computational research is performed to study the deformation and breakup of round nonturbulent liquid jets in uniform gaseous crossflow. Pulsed photography and shadow graphy in conjunction with high-speed imaging were used to study the wave phenomena and the droplets properties/transport dynamics of a nonturbulent liquid jet injected into a uniform crossflow within the bag breakup regime. The computational study extended the previous two-dimensional study by adding the third dimension, allowing the wave properties to be modeled. The computational simulation employed the Volume of Fluid (VOF) formulation of FLUENT, and was run on a 3-processors parallel Linux cluster and P4 desktops. The validated, time-accurate, CFD simulation analyzes the surface properties of the liquid jets within the column, bag, and shear breakup regimes by considering the effects of surface tension, liquid viscosity, and crossflow Weber number at large liquid/gas density ratios (>500) and small Ohnesorge numbers (liquid jet are attributed to Rayleigh-Taylor instabilities and the nodes layout per bag affected the breakup mechanisms of the bags. Three distinctive sizes of droplets were produced in the bag breakup regime. The size of bag-droplets normalized by the nozzle exit diameter was constant. The different trajectories for bag- and node-droplets suggested that separation of bag- and node-droplets is possible. The computational results included jet deformations, jet cross-sectional area, jet velocity, wake velocity defect, wake width, and wavelengths of column and surface waves. Present computational results yielded a similarity solution for the inner wake region. In bag breakup, the lower pressure along the sides of the jet pulled the liquid away from both the upwind and downwind surfaces of the liquid cross-section. In shear breakup, the flattened upwind surface pushed the liquid towards the two sides of the jet. In bag breakup, the flow
Effects of spin-orbit coupling on quantum transport
Bardarson, Jens Hjorleifur
2008-01-01
The effect of spin-orbit coupling on various quantum transport phenomena is considered. The main topics discussed are: * How spin-orbit coupling can induce shot noise through trajectory splitting. * How spin-orbit coupling can degrade electron-hole entanglement (created by a tunnel barrier) by mo
Breakup branches of Borromean beryllium-9
Energy Technology Data Exchange (ETDEWEB)
Smith, R., E-mail: r.smith.3@pgr.bham.ac.uk; Freer, M.; Wheldon, C.; Curtis, N.; Ashwood, N. I.; Barr, M.; Kokalova, Tz.; Malcolm, J. D.; Ziman, V. A. [School of Physics and Astronomy, University of Birmingham, Edgbaston, Birmingham, B15 2TT (United Kingdom); Almaraz-Calderon, S.; Aprahamian, A.; Bucher, B.; Couder, M.; Fang, X.; Jung, F.; Lu, W.; Roberts, A.; Tan, W. P. [Institute for Structure and Nuclear Astrophysics, Department of Physics, University of Notre Dame, Notre Dame, IN 46556 (United States); Copp, P.; Lesher, S. R. [Department of Physics, University of Wisconsin - La Crosse, La Crosse, WI 54601 (United States); and others
2015-10-15
The breakup reaction {sup 9}Be({sup 4}He, 3α)n was measured using an array of four double-sided silicon strip detectors at beam energies of 22 and 26 MeV. Excited states in {sup 9}Be up to 12 MeV were populated and reconstructed through the measurement of the charged reaction products. It is proposed that limits on the spins and parities of the states can be derived from the way that they decay. Various breakup paths for excited states in {sup 9}Be have been explored including the {sup 8}Be{sub g.s.} + n, {sup 8}Be{sub 2{sup +}} + n and {sup 5}He{sub g.s.} + {sup 4}He channels. By imposing the condition that the breakup proceeded via the {sup 8}Be ground state, clean excitation spectra for {sup 9}Be were reconstructed. The remaining two breakup channels were found to possess strongly-overlapping kinematic signatures and more sophisticated methods (referenced) are required to completely disentangle these other possibilities. Emphasis is placed on the development of the experimental analysis and the usefulness of Monte-Carlo simulations for this purpose.
Experimental determination of the effective strong coupling constant
Energy Technology Data Exchange (ETDEWEB)
Alexandre Deur; Volker Burkert; Jian-Ping Chen; Wolfgang Korsch
2005-09-15
We extract an effective strong coupling constant from low Q2 data on the Bjorken sum. Using sum rules, we establish its Q2-behavior over the complete Q2-range. The result is compared to effective coupling constants extracted from different processes and to calculations based on Schwinger-Dyson equations, hadron spectroscopy or lattice QCD. Although the connection between the experimentally extracted effective coupling constant and the calculations is not clear, the results agree surprisingly well.
Quantum dissipative effect of one dimension coupled anharmonic oscillator
Energy Technology Data Exchange (ETDEWEB)
Sulaiman, A. [Badan Pengkajian dan Penerapan Teknologi, BPPT Bld. II (19thfloor), Jl. M.H. Thamrin 8, Jakarta 10340 (Indonesia); Indonesia Center for Theoretical and Mathematical Physics (ICTMP), Jl. Ganesha 10, Bandung 40132 (Indonesia); Zen, Freddy P. [Theoretical Physics Laboratory (THEPI), Department of Physics, Institut Teknologi Bandung, Jl. Ganesha 10, Bandung 40132 (Indonesia); Indonesia Center for Theoretical and Mathematical Physics (ICTMP), Jl. Ganesha 10, Bandung 40132 (Indonesia)
2015-04-16
Quantum dissipative effect of one dimension coupled anharmonic oscillator is investigated. The systems are two coupled harmonic oscillator with the different masses. The dissipative effect is studied based on the quantum state diffusion formalism. The result show that the anharmonic effect increase the amplitude but the lifetime of the oscillation depend on the damping coefficient and do not depend on the temperature.
Investigation of the Deuteron Breakup on Proton Target in the Forward Angular Region at 130 MeV
International Nuclear Information System (INIS)
A set of differential cross-section data of the 1H(d, pp)n breakup reaction at 130 MeV deuteron beam energy has been measured in the domain of very forward polar angles with the use of the Germanium Wall detector at the Forschungszentrum Jülich. The data obtained for over 1000 kinematical points (112 geometries) are compared with the theoretical predictions based on various models of the three-nucleon (3N) dynamics. They comprise: the realistic nucleon-nucleon potentials alone or combined with the three-nucleon force (3NF), the coupled-channel calculations with the explicit treatment of the Δ-isobar excitation and finally, the potentials derived from chiral perturbation theory. In the part of the phase space studied, the Coulomb interaction between protons has a strong impact on the differential cross section of the breakup reaction. The strongest Coulomb effects are found in regions where the relative energy of the two protons is the smallest. In these regions the data are well reproduced exclusively by calculations which include the electromagnetic repulsion between protons. In spite of the dominance of the Coulomb force in the phase space studied, the contribution of 3NF effects is also observed. (author)
Breakup characteristics of power-law liquid sheets formed by two impinging jets
Energy Technology Data Exchange (ETDEWEB)
Bai, Fuqiang; Diao, Hai; Chang, Qing; Wang, Endong; Du, Qing [State Key Laboratory of Engines, Tianjin University, Tianjin, 300072, People’s Republic of China (China); Zhang, Mengzheng, E-mail: duqing@tju.edu.cn [Xi’an Aerospace Propulsion Institute, Xi’an, 710100, People’s Republic of China (China)
2014-10-01
The breakup characteristics of the shear-thinning power-law liquid sheets formed by two impinging jets have been investigated with the shadowgraph technique. This paper focuses on the effects of spray parameters (jet velocity), physical parameters (viscosity) and geometry parameters (impinging angle and nozzle cross-sectional shape) on the breakup behaviors of liquid sheets. The breakup mode, sheet length and expansion angle of the sheet are extracted from the spray images obtained by a high speed camera. Impinging angle and Weber number play the similar roles in promoting the breakup of liquid sheets. With the increase of jet velocity, five different breakup modes are observed and the expansion angle increases consistently after the closed-rim mode while the sheet length first increases and then decreases. But there exists a concave consisting of a fierce drop and a second rising process on the sheet length curve for the fluid with smaller viscosity. Different nozzle cross-sectional shapes emphasize significant effects on the sheet length and expansion angle of liquid sheets. At a fixed Weber number, the liquid sheet with greater viscosity has a greater sheet length and a smaller expansion angle due to the damping effect of viscosity. (papers)
Fluctuation effects on QCD phase diagram at strong coupling
Ichihara, Terukazu
2015-01-01
We study the QCD phase diagram away from the strong coupling limit (SCL) with fluctuation effects in the auxiliary field Monte-Carlo (AFMC) method. First, we give an effective action which contains next-to-leading order (NLO) finite coupling effects of the strong coupling expansion as well as fluctuation effects. Second, we examine NLO effects of the strong coupling expansion in AFMC at zero quark density. We find that the chiral condensate is reduced by both NLO terms from temporal plaquettes and fluctuation effects, and almost no dependence on NLO terms from spatial plaquettes in the current analysis. These behaviors can be understood from the modification of the mass and the wave function renormalization factor by auxiliary fields as in the mean field analysis and the fluctuation effects in the strong coupling limit.
Effects of spin-orbit coupling on quantum transport
Bardarson, Jens Hjorleifur
2008-01-01
The effect of spin-orbit coupling on various quantum transport phenomena is considered. The main topics discussed are: * How spin-orbit coupling can induce shot noise through trajectory splitting. * How spin-orbit coupling can degrade electron-hole entanglement (created by a tunnel barrier) by mode mixing. * Mesoscopic Spin Hall effect: longitudinal charge current leads to transverse spin currents in a chaotic electron cavity which has universal fluctuations around a zero mean. * How smooth d...
Quark and pion effective couplings from polarization effects
Braghin, Fabio L
2016-01-01
A flavor SU(2) effective model for pions and quarks is derived by considering polarization effects departing from the usual quark-quark effective interaction induced by dressed gluon exchange, i.e. a global color model for QCD. For that, the quark field is decomposed into a component that yields light mesons and the quark-antiquark condensate, being integrated out by means of the auxiliary field method, and another component which yields constituent quarks. Within a longwavelength and weak quark field expansion (or large quark effective mass expansion) of a quark determinant, the leading terms are found up to the second order in a zero order derivative expansion, by neglecting vector mesons that are considerably heavier than the pion. Pions are considered in the structureless limit and, besides the chiral invariant pion self interaction terms that reproduce previously derived expressions, symmetry breaking terms are also presented. The leading chiral quark-quark effective couplings are also found correspondin...
Lima, V; Lacroix, D; Blumenfeld, Y; Bourgeois, C; Chabot, M; Chomaz, Ph; Désesquelles, P; Duflot, V; Duprat, J; Fallot, M; Frascaria, N; Grévy, S; Guillemaud-Müller, D; Roussel-Chomaz, P; Savajols, H; Sorlin, O
2007-01-01
The break-up of 11Be was studied at 41AMeV using a secondary beam of 11Be from the GANIL facility on a 48Ti target by measuring correlations between the 10Be core, the emitted neutrons and gamma rays. The nuclear break-up leading to the emission of a neutron at large angle in the laboratory frame is identified with the towing mode through its characteristic n-fragment correlation. The experimental spectra are compared with a model where the time dependent Schrodinger equation (TDSE) is solved for the neutron initially in the 11 Be. A good agreement is found between experiment and theory for the shapes of neutron experimental energies and angular distributions. The spectroscopic factor of the 2s orbital is tentatively extracted to be 0.46+-0.15. The neutron emission from the 1p and 1d orbitals is also studied.
Directory of Open Access Journals (Sweden)
Zhang Liang
2015-01-01
Full Text Available To research an effective measure of reducing the Soot and NOx in engine at the same time, different nozzle hole diameters coupled with exhaust gas recirculation (EGR were adopted in this study based on KH-ACT spray breakup model, which takes the aerodynamic-induced ,cavitation-induced and turbulence-induced breakup into account. The SAGE detailed chemistry combustion and the new atomization model used in the simulation have been verified with the experiment data from a YN4100QBZL engine. Different diesel nozzles was adopted in the study combined with different EGR rates ranging from 0% to 40%. The simulation results show that the NOx emission could be reduced effectively for both small(0.1mm and large(0.15mm diesel nozzle when increasing EGR ratio. The soot emission increases for the small nozzle hole size as the EGR increasing. However, when it comes to the large diesel nozzle, the emission increases slightly first and decrease quickly when the EGR rate above 20%.
Breakup of Pack Ice, Antarctic Ice Shelf
1991-01-01
Breakup of Pack Ice along the periphery of the Antarctic Ice Shelf (53.5S, 3.0E) produced this mosaic of ice floes off the Antarctic Ice Shelf. Strong offshore winds, probably associated with strong katabatic downdrafts from the interior of the continent, are seen peeling off the edges of the ice shelf into long filamets of sea ice, icebergs, bergy bits and growlers to flow northward into the South Atlantic Ocean. 53.5S, 3.0E
Fractal aggregation and breakup of fine particles
Directory of Open Access Journals (Sweden)
Li Bingru
2016-01-01
Full Text Available Breakup may exert a controlling influence on particle size distributions and particles either are fractured or are eroded particle-by-particle through shear. The shear-induced breakage of fine particles in turbulent conditions is investigated using Taylor-expansion moment method. Their equations have been derived in continuous form in terms of the number density function with particle volume. It suitable for future implementation in computational fluid dynamics modeling.
Inter-dot coupling effects on transport through correlated parallel coupled quantum dots
Indian Academy of Sciences (India)
Shyam Chand; G Rajput; K C Sharma; P K Ahluwalia
2009-05-01
Transport through symmetric parallel coupled quantum dot system has been studied, using non-equilibrium Green function formalism. The inter-dot tunnelling with on-dot and inter-dot Coulomb repulsion is included. The transmission coefficient and Landaur–Buttiker like current formula are shown in terms of internal states of quantum dots. The effect of inter-dot tunnelling on transport properties has been explored. Results, in intermediate inter-dot coupling regime show signatures of merger of two dots to form a single composite dot and in strong coupling regime the behaviour of the system resembles the two decoupled dots.
Recent developments in the eikonal description of the breakup of exotic nuclei
Capel, P; Esbensen, H; Fukui, T; Johnson, R C; Nunes, F M; Ogata, K
2015-01-01
The study of exotic nuclear structures, such as halo nuclei, is usually performed through nuclear reactions. An accurate reaction model coupled to a realistic description of the projectile is needed to correctly interpret experimental data. In this contribution, we briefly summarise the assumptions made within the modelling of reactions involving halo nuclei. We describe briefly the Continuum-Discretised Coupled Channel method (CDCC) and the Dynamical Eikonal Approximation (DEA) in particular and present a comparison between them for the breakup of 15C on Pb at 68AMeV. We show the problem faced by the models based on the eikonal approximation at low energy and detail a correction that enables their extension down to lower beam energies. A new reaction observable is also presented. It consists of the ratio between angular distributions for two different processes, such as elastic scattering and breakup. This ratio is completely independent of the reaction mechanism and hence is more sensitive to the projectile...
Numerical simulation of liquid jet breakup using smoothed particle hydrodynamics (SPH)
Pourabdian, Majid; Morad, Mohammad Reza
2016-01-01
In this paper, breakup of liquid jet is simulated using smoothed particle hydrodynamics (SPH) which is a meshless Lagrangian numerical method. For this aim, flow governing equations are discretized based on SPH method. In this paper, SPHysics open source code has been utilized for numerical solutions. Therefore, the mentioned code has been developed by adding the surface tension effects. The proposed method is then validated using dam break with obstacle problem. Finally, simulation of twodimensional liquid jet flow is carried out and its breakup behavior considering one-phase flow is investigated. Length of liquid breakup in Rayleigh regime is calculated for various flow conditions such as different Reynolds and Weber numbers and the results are validated by an experimental correlation. The whole numerical solutions are accomplished for both Wendland and cubic spline kernel functions and Wendland kernel function gave more accurate results. The results are compared to MPS method for inviscid liquid as well. T...
Coulomb versus nuclear break-up of 11Be halo nucleus in a non perturbative framework
Fallot, M; Lacroix, D; Chomaz, P; Margueron, J; Chomaz, Ph.
2002-01-01
The 11Be break-up is calculated using a non perturbative time-dependent quantum calculation. The evolution of the neutron halo wave function shows an emission of neutron at large angles for grazing impact parameters and at forward angles for large impact parameters. The neutron angular distribution is deduced for the different targets and compared to experimental data. We emphasize the diversity of diffraction mechanisms, in particular we discuss the interplay of the nuclear effects such as the towing mode and the Coulomb break-up. A good agreement is found with experimental data.
Velocity perturbation distributions in the breakup of artificial satellites
Badhwar, Gautam D.; Tan, Arjun; Reynolds, Robert C.
1990-01-01
A method is presented for calculating the three orthogonal components of the velocity perturbations of satellite fragments, with a view to ascertaining the nature and intensity of the satellite breakup. The method employs three simultaneous equations furnished by changes in fragment specific energy, specific angular momentum, and plane orientation. Velocity perturbations are thereby calculated for fragments from 20 major satellite breakup events; these results, in conjunction with a technique for determining fragment masses, yield a description of the breakup process.
DEFF Research Database (Denmark)
Kriegbaum, Margit; Christensen, Ulla; Andersen, Per Kragh;
2013-01-01
Marriage is associated with lower risk of coronary heart disease, but it is unknown if the association depends on time since break-up with a partner. In this study we included both married and unmarried couples to study if the association between broken partnership (BP) and first time incident...
Energy Technology Data Exchange (ETDEWEB)
Fernández-García, J. P., E-mail: fernandez@lns.infn.it; Di Pietro, A.; Figuera, P.; Fisichella, M. [INFN, Laboratori Nazionali del Sud, via S. Sofia 62, 1-95123 Catania (Italy); Lattuada, M.; Musumarra, A.; Pellegriti, M. G.; Scuderi, V.; Torresi, D. [INFN, Laboratori Nazionali del Sud, via S. Sofia 62, 1-95123 Catania (Italy); Dipartamento di Fisica e Astronomia, via S. Sofia 64, I-95123 Catania (Italy); Moro, A. M. [Departamento de FAMN, Universidad de Sevilla, Apartado 1065, E-41080 Seville (Spain); Zadro, M. [Ruder Bošković Institute, Bijenička cesta 54, HR-10000 Zagreb (Croatia)
2015-10-15
The experimental elastic scattering angular distributions for the weakly bound nuclei {sup 6,7}Li and for the halo nucleus {sup 6}He on the same {sup 64}Zn target at several energies around the Coulomb barrier were measured at the Laboratori Nazionali del Sud (LNS, Italy) and at the Cyclotron Research Center, Louvain La Neuve (Belgium), respectively. The measured elastic scattering angular distributions of these three systems at the same center of mass energy have been compared. The experimental data of the {sup 6,7}Li+ {sup 64}Zn systems have been analyzed within the CDCC method, while the {sup 6}He+{sup 64}Zn data have been compared with both both CDCC and CRC calculations.
Coupled channels effects in heavy ion elastic scattering
Energy Technology Data Exchange (ETDEWEB)
Bond, P.D.
1977-01-01
The effects of inelastic excitation on the elastic scattering of heavy ions are considered within a coupled channels framework. Both Coulomb and nuclear excitation results are applied to /sup 18/O + /sup 184/W and other heavy ion reactions. (SDF)
Larson, Matthew; Sweeten, Gary; Piquero, Alex R
2016-01-01
The decline and delay of marriage has prolonged adolescence and the transition to adulthood, and consequently fostered greater romantic relationship fluidity during a stage of the life course that is pivotal for both development and offending. Yet, despite a growing literature of the consequences of romantic relationships breakup, little is known about its connection with crime, especially among youth enmeshed in the criminal justice system. This article addresses this gap by examining the effects of relationship breakup on crime among justice-involved youth-a key policy-relevant group. We refer to data from the Pathways to Desistance Study, a longitudinal study of 1354 (14% female) adjudicated youth from the juvenile and adult court systems in Phoenix and Philadelphia, to assess the nature and complexity of this association. In general, our results support prior evidence of breakup's criminogenic influence. Specifically, they suggest that relationship breakup's effect on crime is particularly acute among this at-risk sample, contingent upon post-breakup relationship transitions, and more pronounced for relationships that involve cohabitation. Our results also extend prior work by demonstrating that breakup is attenuated by changes in psychosocial characteristics and peer associations/exposure. We close with a discussion of our findings, their policy implications, and what they mean for research on relationships and crime among serious adolescent offenders moving forward. PMID:26092231
Coriolis cross-coupling effects: disorienting and nauseogenic or not?
Guedry, F E; Benson, A J
1978-01-01
Nausea and disorientation are sometimes produced by head movements during turning maneuvers in aircraft. These responses are usually attributed to Coriolis cross-coupling stimulation of the vestibular system, although it has been indicated recently that many turning maneuvers of aircraft have insufficient angular velocity to generate such effects. The purpose of the present study was to further distinguish conditions in which Coriolis cross-coupling effects are disorienting and nauseogenic from conditions in which they are neither.
Percolation picture of nucleus break-up
International Nuclear Information System (INIS)
The production of nuclear fragments in multifragmentation and spallation reactions is viewed as a percolation phenomenon. A model of nuclear percolation is proposed. The criteria for linkage of nucleons to a cluster are defined in real and momentum spaces. In addition, ''compactness'' conditions are imposed to the clusters in both spaces. This model behaves in many respects as a two-dimensional site percolation model, exhibiting a rather well defined percolation threshold at psub(c) approximately 0.6. The concentration p is related to the number of fast particles leaving the nuclear volume. We discuss possible experimental signatures of this new break-up mechanism
Gordillo, J.M.; Gekle, Stephan
2010-01-01
The capillary breakup of the high-speed Worthington jets ejected after a cavity collapse in water occurs due to the high-Reynolds-number version of the capillary end-pinching mechanism first described, in the creeping flow limit, by Stone & Leal (J. Fluid Mech., vol. 198, 1989, p. 399). Using potent
Effect of interfacial coupling on rectification in organic spin rectifiers
Hu, Gui-Chao; Zuo, Meng-Ying; Li, Ying; Zhang, Zhao; Ren, Jun-Feng; Wang, Chuan-Kui
2015-07-01
The effect of interfacial coupling on rectification in an organic co-oligomer spin diode is investigated theoretically by considering spin-independent and spin-resolved couplings respectively. In the case of spin-independent coupling, an optimal interfacial coupling strength with a significant enhanced rectification ratio is found, whose value depends on the structural asymmetry of the molecule. In the case of spin-resolved coupling, we found that only the variation of the interfacial coupling with specific spin is effective to modulate the rectification, which is due to the spin-filtering property of the central asymmetric magnetic molecule. A transition of the spin-current rectification between parallel spin-current rectification and antiparallel spin-current rectification may be observed with the variation of the spin-resolved interfacial coupling. The interfacial effect on rectification is further analyzed from the spin-dependent transmission spectrum at different biases. Project supported by the National Natural Science Foundation of China (Grant No. 1374195), the Natural Science Foundation of Shandong Province, China (Grant No. ZR2014AM017), and the Excellent Young Scholars Research Fund of Shandong Normal University, China.
Type of Writing Task and College Students' Meaning Making Following a Romantic Breakup
Primeau, Joanna E.; Servaty-Seib, Heather L.; Enersen, Donna
2013-01-01
In this study, the authors examined the potential effects of type of writing task (loss/gain vs. general prompt) on the narrative content offered by college students (N = 41) who experienced romantic breakup. Qualitative analyses indicated differences based on type of writing task. Students who received the loss/gain prompt exhibited more…
Interchannel coupling effects in the valence photoionization of SF6
Jose, Jobin; Lucchese, Robert; Rescigno, Tom
2014-05-01
The complex Kohn and polyatomic Schwinger variational techniques have been employed to illustrate the interchannel coupling correlation effects in the valence photoionization dynamics of SF6. Partial photoionization cross sections and asymmetry parameters of six valence subshells (1t1 g, 5t1 u, 1t2 u, 3eg, 1t2 g, 4t1 u) are discussed in the framework of several theoretical and experimental studies. The complex Kohn results are in rather good agreement with experimental results, indicative of the fact that the interchannel coupling effects alter the photoionization dynamics significantly. We find that the dominant effect of interchannel coupling is to reduce the magnitude of shape resonant cross sections near threshold and to induce resonant features in other channels to which resonances are coupled.
Breakup Behavior of Molten Wood's Metal Jet in Subcooled Water
Energy Technology Data Exchange (ETDEWEB)
Heo, Hyo; Park, Seong Dae; Bang, In Cheol [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of); Jerng, Dong Wook [Chung-Ang Univ., Seoul (Korea, Republic of)
2014-10-15
There are safety characteristics of the metal fueled sodium fast-cooled reactor (SFR), by identifying the possibility of early termination of severe accidents. If the molten fuel is ejected from the cladding, the ejected molten fuel can interact with the coolant in the reactor vessel. This phenomenon is called as fuel-coolant interaction (FCI). The FCI occurs at the initial phase leading to severe accidents like core disruptive accident (CDA) in the SFR. A part of the corium energy is intensively transferred to the coolant in a very short time during the FCI. The coolant vaporizes at high pressure and expands so results in steam explosion that can threat to the integrity of nuclear reactor. The intensity of steam explosion is determined by jet breakup and the fragmentation behavior. Therefore, it is necessary to understand the jet breakup between the molten fuel jet and the coolant in order to evaluate whether the steam explosion occurs or not. The liquid jet breakup has been studied in various areas, such as aerosols, spray and combustion. In early studies, small diameter jets of low density liquids were studied. The jet breakup for large density liquids has been studied in nuclear reactor field with respect to safety. The existence of vapor film layer between the melt and liquid fluid is only in case of large density breakup. This paper deals with the jet breakup experiment in non-boiling conditions in order to analyze hydraulic effect on the jet behavior. In the present study, the wood's metal was used as the jet material. It has similar properties to the metal fuel. The physical properties of molten materials and coolants are listed in Table I, respectively. It is easy to conduct the experiment due to low melting point of the wood's metal. In order to clarify the dominant factors determining jet breakup and size distribution of the debris, the experiment that the molten wood's metal was injected into the subcooled condition was conducted. The
Breakup Behavior of Molten Wood's Metal Jet in Subcooled Water
International Nuclear Information System (INIS)
There are safety characteristics of the metal fueled sodium fast-cooled reactor (SFR), by identifying the possibility of early termination of severe accidents. If the molten fuel is ejected from the cladding, the ejected molten fuel can interact with the coolant in the reactor vessel. This phenomenon is called as fuel-coolant interaction (FCI). The FCI occurs at the initial phase leading to severe accidents like core disruptive accident (CDA) in the SFR. A part of the corium energy is intensively transferred to the coolant in a very short time during the FCI. The coolant vaporizes at high pressure and expands so results in steam explosion that can threat to the integrity of nuclear reactor. The intensity of steam explosion is determined by jet breakup and the fragmentation behavior. Therefore, it is necessary to understand the jet breakup between the molten fuel jet and the coolant in order to evaluate whether the steam explosion occurs or not. The liquid jet breakup has been studied in various areas, such as aerosols, spray and combustion. In early studies, small diameter jets of low density liquids were studied. The jet breakup for large density liquids has been studied in nuclear reactor field with respect to safety. The existence of vapor film layer between the melt and liquid fluid is only in case of large density breakup. This paper deals with the jet breakup experiment in non-boiling conditions in order to analyze hydraulic effect on the jet behavior. In the present study, the wood's metal was used as the jet material. It has similar properties to the metal fuel. The physical properties of molten materials and coolants are listed in Table I, respectively. It is easy to conduct the experiment due to low melting point of the wood's metal. In order to clarify the dominant factors determining jet breakup and size distribution of the debris, the experiment that the molten wood's metal was injected into the subcooled condition was conducted. The
Cost effective optical coupling for polymer optical fiber communication
Chandrappan, Jayakrishnan; Zhang, Jing; Mohan, Ramkumar V.; Gomez, Philbert Oliver; Aung, Than Aye; Xiao, Yongfei; Ramana, Pamidighantam V.; Lau, John Hon Shing; Kwong, Dim Lee
2008-02-01
Polymer Optical Fiber (POF) optical modules are gaining momentum due to their applications in short distance communications. POFs offer more flexibility for plug and play applications and provide cost advantages. They also offer significant weight advantage in automotive and avionic networks. One of the most interesting field of application is home networking. Low cost optical components are required, since cost is a major concern in local and home networks. In this publication, a fast and easy to install, low cost solution for efficient light coupling in and out of Step Index- POF is explored. The efficient coupling of light from a large core POF to a small area detector is the major challenge faced. We simulated direct coupling, lens coupling and bend losses for step index POF using ZEMAX R optical simulation software. Simulations show that a lensed fiber tip particularly at the receiver side improves the coupling efficiency. The design is optimized for 85% coupling efficiency and explored the low cost fabrication method to implement it in the system level. The two methods followed for lens fabrication is described here in detail. The fabricated fiber lenses are characterized using a beam analyzer. The fabrication process was reiterated to optimize the lens performance. It is observed that, the fabricated lenses converge the POF output spot size by one fourth, there by enabling a higher coupling efficiency. This low cost method proves to be highly efficient and effective optical coupling scheme in POF communications.
International Nuclear Information System (INIS)
A hybrid atomization and breakup model was developed for the simulation of the fuel injection processes of multi-hole injectors for direct injection spark ignition (DISI) gasoline engines. In modeling primary breakup, a competition between the Huh–Gosman and Kelvin–Helmholtz (KH) breakup mechanisms was adopted. In addition to the two breakup mechanisms above, the Rayleigh–Taylor (RT) model was selected as a third competing mechanism in simulating secondary breakup. The hybrid model was implemented in the Star-CD software to simulate the effect of the background and injection pressures on the breakup processes of gasoline jets in a constant volume vessel, and on the mixture stratification of a wall-guided DISI gasoline engine with a newly-designed cavity in the piston. Results indicate that a higher background pressure intensifies the aerodynamically induced breakup along the tip of spray although it tends to reduce the overall breakup of spray. The spray atomization enhanced by increasing injection pressures is more pronounced at elevated background pressures. With the retard of fuel injection timing, the inhomogeneity of mixture increases in the DISI gasoline engine. Double injection with elevated second injection pressure can reduce the overall inhomogeneity of the mixture and effectively direct the mixture towards the spark plug. - Highlights: •A hybrid breakup model was developed to simulate injection process in a DISI engine. •Higher fuel injection pressure enhances breakup and evaporation at the spray tip. •Single fuel injection leads to a narrow spark timing range. •Two-stage fuel injection improves the homogeneity of the mixture. •The second injection with higher fuel pressure decreases over-rich mixture
University Students' Experiences of Nonmarital Breakups: A Grounded Theory
Hebert, Sarah; Popadiuk, Natalee
2008-01-01
Prior nonmarital breakup research has been focused on negative outcomes, rarely examining the personal growth aspects of this experience. In this study, we used a qualitative grounded theory methodology to explore the changes that university students reported experiencing as a result of a heterosexual nonmarital breakup and how those changes…
24 CFR 982.315 - Family break-up.
2010-04-01
... 24 Housing and Urban Development 4 2010-04-01 2010-04-01 false Family break-up. 982.315 Section... SECTION 8 TENANT BASED ASSISTANCE: HOUSING CHOICE VOUCHER PROGRAM Leasing a Unit § 982.315 Family break-up... assistance in the program if the family breaks up. The PHA administrative plan must state PHA policies on...
Theoretical study of the elastic breakup of weakly bound nuclei at near barrier energies
Otomar, D R; Lubian, J; Canto, L F; Hussein, M S
2015-01-01
We have performed CDCC calculations for collisions of $^{7}$Li projectiles on $^{59}$Co, $^{144}$Sm and $^{208}$Pb targets at near-barrier energies, to assess the importance of the Coulomb and the nuclear couplings in the breakup of $^{7}$Li, as well as the Coulomb-nuclear interference. We have also investigated scaling laws, expressing the dependence of the cross sections on the charge and the mass of the target. This work is complementary to the one previously reported by us on the breakup of $^{6}$Li. Here we explore the similarities and differences between the results for the two Lithium isotopes. The relevance of the Coulomb dipole strength at low energy for the two-cluster projectile is investigated in details.
Determination of 8B(p,gamma)9C reaction rate from 9C breakup
Fukui, Tokuro; Minomo, Kosho; Yahiro, Masanobu
2012-01-01
The astrophysical factor of the 8B(p,gamma)9C at zero energy, S18(0), is determined from three-body model analysis of 9C breakup processes. The elastic breakup 208Pb(9C,p8B)208Pb at 65 MeV/nucleon and the one-proton removal reaction of 9C at 285 MeV/nucleon on C and Al targets are calculated with the continuum-discretized coupled-channels method (CDCC) and the eikonal reaction theory (ERT), respectively. The asymptotic normalization coefficient (ANC) of 9C in the p-8B configuration extracted from the two reactions show good consistency, in contrast to in the previous studies. As a result of the present analysis, S18(0) = 66 \\pm 10 eVb is obtained.
Limits on Higgs boson couplings in Effective field theory
Belyaev, N.; Reid, T.
2016-02-01
We review the Effective Field Theory (EFT) to make projections on physics beyond the Standard Model in the Higgs sector. We provide relations between the non-Standard Model couplings of the Strongly-Interacting Light Higgs (SILH) effective Lagrangian implemented in the eHDecay package and the corresponding terms of the spin-0 Higgs Characterisation model's effective Lagrangian used with the aMC@NLO Monte Carlo generator. Constraints on BSM couplings are determined on the basis of existing experimental limits on Higgs boson width and branching ratios.
Zinc isotope discrimination effect in inductively coupled plasma mass spectrometer
International Nuclear Information System (INIS)
Inductively coupled plasma mass spectrometry (ICPMS) has recently been used for isotope ratio analysis. The isotope discrimination effect in the mass spectrometer is a primary factor contributing to loss of precision and accuracy in isotope ratio analysis. The discrimination effect of zinc isotopes was investigated by comparing the results obtained using a quadrupole type ICPMS with those obtained using a thermal ionization mass spectrometer
Elastic nucleon-deuteron scattering and breakup with chiral forces
Directory of Open Access Journals (Sweden)
Witała Henryk
2016-01-01
Full Text Available Results on three-nucleon (3N elastic scattering and breakup below the pion production threshold are discussed. The large discrepancies found between a theory based on numerical solutions of 3N Faddeev equations with standard nucleon-nucleon (NN potentials only and data point to the need for three-nucleon forces (3NF’s. This notion is supported by the fact that another possible reason for the discrepancies in elastic nucleon-deuteron (Nd scattering, relativistic effects, turned out to be small. Results for a new generation of chiral NN forces (up to N4LO together with theoretical truncation errors are shown. They support conclusions obtained with standard NN potentials
Effect of Coriolis coupling in chemical reaction dynamics.
Chu, Tian-Shu; Han, Ke-Li
2008-05-14
It is essential to evaluate the role of Coriolis coupling effect in molecular reaction dynamics. Here we consider Coriolis coupling effect in quantum reactive scattering calculations in the context of both adiabaticity and nonadiabaticity, with particular emphasis on examining the role of Coriolis coupling effect in reaction dynamics of triatomic molecular systems. We present the results of our own calculations by the time-dependent quantum wave packet approach for H + D2 and F(2P3/2,2P1/2) + H2 as well as for the ion-molecule collisions of He + H2 +, D(-) + H2, H(-) + D2, and D+ + H2, after reviewing in detail other related research efforts on this issue.
Comment on breakup densities of hot nuclei
International Nuclear Information System (INIS)
In [V.E. Viola et al., Phys. Rev. Lett. 93 (2004) 132701, D.S. Bracken et al., Phys. Rev. C 69 (2004) 034612] the observed decrease in spectral peak energies of IMFs emitted from hot nuclei was interpreted in terms of a breakup density that decreased with increasing excitation energy. Subsequently, Raduta et al. [Ad. Raduta et al., Phys. Lett. B 623 (2005) 43] performed MMM simulations that showed decreasing spectral peaks could be obtained at constant density. In this Letter we point out that this apparent inconsistency is due to a selective comparison of theory and data that overlooks the evolution of the fragment multiplicities as a function of excitation energy
Direct coupled amplifiers using field effect transistors
International Nuclear Information System (INIS)
The concept of the uni-polar field effect transistor (P.E.T.) was known before the invention of the bi-polar transistor but it is only recently that they have been made commercially. Being produced as yet only in small quantities, their price imposes a restriction on use to circuits where their peculiar properties can be exploited to the full. One such application is described here where the combination of low voltage drift and relatively low input leakage current are necessarily used together. One of the instruments used to control nuclear reactors has a logarithmic response to the mean output current from a polarised ionisation chamber. The logarithmic signal is then differentiated electrically, the result being displayed on a meter calibrated to show the reactor divergence or doubling time. If displayed in doubling time the scale is calibrated reciprocally. Because of the wide range obtained in the logarithmic section and the limited supply voltage, an output of 1 volt per decade change in ionisation current is used. Differentiating this gives a current of 1.5 x 10-8 A for p.s.D. (20 sec. doubling time) in the differentiating amplifier. To overcome some of the problems of noise due to statistical variations in input current, the circuit design necessitates a resistive path to ground at the amplifier input of 20 M.ohms. A schematic diagram is shown. 1. It is evident that a zero drift of 1% can be caused by a leakage current of 1.5 x 10-10 A or an offset voltage of 3 mV at the amplifier input. Although the presently used electrometer valve is satisfactory from the point of view of grid current, there have been sudden changes in grid to grid voltage (the valve is a double triode) of up to 10 m.V. It has been found that a pair of F.E.T's. can be used to replace the electrometer valve so long as care is taken in correct balance of the two devices. An investigation has been made into the characteristics of some fourteen devices to see whether those with very different
Breakup fusion theory of nuclear reactions
International Nuclear Information System (INIS)
Continuum spectra of particles emitted in incomplete fusion reactions are one of the major interests in current nuclear reaction studies. Based on an idea of the so-called breakup fusion (BF) reaction, several authors derived closed formulas for the singles cross section of the particles that are emitted. There have been presented, however, two conflicting cross section formulas for the same BF reaction. For convenience, we shall call one of them the IAV (Ichimura, Austern and Vincent) and the other UT (Udagawa and Tamura) cross section formulas. In this work, the formulation of the UT cross section formula (prior-form) is presented, and the post-form version of the IAV cross section formula is evaluted for a few α- and d-induced reactions based on the exact finite range method. It is shown that the values thus calculated are larger by an order of magnitude as compared with the experimental cross sections for the α-induced reactions, while they are comparable with the experimental cross sections for the d-induced reactions. A possible origin of why such a large cross section is resulted in the case of α-induced reactions is also discussed. Polarization of the residual compound nucleus produced in breakup fusion reactions are calculated and compared with experiments. It is shown that the polarization is rather sensitive to the deflection angles of the strongly absortive partial waves and to obtain a good fit with the experimental data a l-dependent potential in the incident channel is needed in order to stress the lower partial waves
Simulating Topological Effects with Photons in Coupled QED Cavity Arrays
Noh, Changsuk; Angelakis, Dimitris G.
2014-01-01
We provide a pedagogical account of an early proposal realizing fractional quantum Hall effect (FQHE) using coupled quantum electrodynamics (QED) cavity arrays (CQCAs). We start with a brief introduction on the basics of quantum Hall effects and then review the early proposals in the simulation of spin-models and fractional quantum Hall (FQH) physics with photons in coupled atom-cavity arrays. We calculate the energy gap and the overlap between the ground state of the system and the corresponding Laughlin wavefunction to analyze the FQH physics arising in the system and discuss possibilities to reach the ground state using adiabatic methods used in Cavity QED.
Trumbull, Robert B.
2014-05-01
after breakup. Unexpected are the implied short time and spatial scales of topographic variations, which challenge conventional wisdom on how passive margins evolve. These variations in surface topography are critical observables for testing models of shallow vs. deep-mantle buoyancy effects. Studies of sedimentary basins offshore complement the denudation studies and are linked with 3D lithospheric models of the margins. A group of projects examines structures, sedimentary sequences and thermal/subsidence histories of selected conjugate basins, and finds major asymmetries. Allied studies of hydrocarbon systems in the basins involve mapping present and paleo gas escape/sequestration features (mud volcanoes, pockmarks, gas chimneys) combined with 3D petroleum systems models. Relating the offshore sedimentary record to lithospheric dynamics requires understanding effects of paleo-oceanography. Major changes in Atlantic circulation due to tectonic events and the geometry of the ocean basin are recorded in erosive and depositional features of offshore sediments. SAMPLE projects use high-resolution seismic data to map and date these features, and in a further step, to study the influence of paleo-ocean circulation on global climate using coupled atmosphere-ocean models.
Effect of interlayer exchange coupling on magnetic chiral structures
Energy Technology Data Exchange (ETDEWEB)
Kang, S. P.; Kwon, H. Y.; Kim, H. S.; Shim, J. H.; Won, C. [Department of Physics, Kyung Hee University, Seoul 130-701 (Korea, Republic of)
2015-07-28
We numerically investigated the effect of interlayer exchange coupling on magnetic chiral structures, such as a helical/cycloidal spin structure and magnetic skyrmion crystal (SkX), which are produced in a magnetic system involving the Dzyaloshinskii-Moriya interaction (DMI). We report the existence of a phase transition where the length scale of magnetic structure discontinuously changes, and that there can be a novel magnetic structure around the phase boundary that exhibits double-ordering lengths of magnetic structure. Therefore, the system has multiple ground phases determined by the ratio of interlayer exchange coupling strength and DMI strength. Furthermore, we investigated the critical condition of the external perpendicular field required for the SkX. The critical field is significantly reduced under the effect of interlayer exchange coupling, which can stabilize the SkX without the external field.
International Nuclear Information System (INIS)
Inclusive alpha particle and deuteron spectra from collisions of 156 MeV 6Li-ions with 12C and 208Pb were measured at extreme forward emission angles including zero degree. The measurements were performed with the Karlsruhe magnetic spectrograph 'Little John' and required an efficient reduction of the background from small-angle scattering. The observed double differential cross sections and angular distributions have been analysed on the basis of Serber's spectator break-up model. When going to angles smaller than grazing, where Coulomb effects are expected to the dominating, transitional features may appear. Corresponding effects probably associated with Coulomb break-up are observed with the 208Pb-target and require a slight extension of the Serber approach. In the case of the 12C-target the break-up cross sections in forward direction seem to reflect the shape of the internal momentum distribution of the alpha particle and deuteron cluster in the 6Li-projectile and are in agreement with a 2S-type wave function. However, at larger angles the shape appears to be distorted, possibly by final state interactions. (orig.)
Trilinear Neutral Gauge Boson Couplings in Effective Theories
Larios, F; Tavares-Velasco, G; Toscano, J J
2001-01-01
We list all the lowest dimension effective operators inducing off-shell trilinear neutral gauge boson couplings Z-Z-Photon, Z-Photon-Photon, and ZZZ within the effective Lagrangian approach, both in the linear and nonlinear realizations of the SU(2)_{L} X U(1)_Y gauge symmetry. In the linear scenario we find that these couplings can be generated only by dimension eight operators necessarily including the Higgs boson field, whereas in the nonlinear case they are induced by dimension six operators. We consider the impact of these couplings on some precision measurements such as the magnetic and electric dipole moments of fermions, as well as the Z boson rare decay Z -> neutrino+antineutrino+ photon. If the underlying new physics is of a decoupling nature, it is not expected that trilinear neutral gauge boson couplings may affect considerably any of these observables. On the contrary, it is just in the nonlinear scenario where these couplings have the more promising prospects of being perceptible through high pr...
Trilinear neutral gauge boson couplings in effective theories
Larios, F.; Pérez, M. A.; Tavares-Velasco, G.; Toscano, J. J.
2001-06-01
We list all the lowest dimension effective operators inducing off-shell trilinear neutral gauge boson couplings ZZγ, Zγγ, and ZZZ within the effective Lagrangian approach, both in the linear and nonlinear realizations of SU(2)L × U(1)Y gauge symmetry. In the linear scenario we find that these couplings can be generated only by dimension-8 operators necessarily including the Higgs boson field, whereas in the nonlinear case they are induced by dimension-6 operators. We consider the impact of these couplings on some precision measurements such as the magnetic and electric dipole moments of fermions, as well as the Z boson rare decay Z-->νν¯γ. If the underlying new physics is of a decoupling nature, it is not expected that trilinear neutral gauge boson couplings may affect considerably any of these observables. On the contrary, it is just in the nonlinear scenario where these couplings have the more promising prospects of being perceptible through high precision experiments.
The TAB method for numerical calculation of spray droplet breakup
Orourke, P. J.; Amsden, A. A.
A short history is given of the major milestones in the development of the stochastic particle method for calculating liquid fuel sprays. The most recent advance has been the discovery of the importance of drop breakup in engine sprays. A new method, called TAB, for calculating drop breakup is presented. Some theoretical properties of the method are derived; its numerical implementation in the computer program KIVA is described; and comparisons are presented between TAB-method calculations and experiments and calculations using another breakup model.
Synchronization of coupled stochastic oscillators: The effect of topology
Indian Academy of Sciences (India)
Amitabha Nandi; Ram Ramaswamy
2008-06-01
We study sets of genetic networks having stochastic oscillatory dynamics. Depending on the coupling topology we find regimes of phase synchronization of the dynamical variables. We consider the effect of time-delay in the interaction and show that for suitable choices of delay parameter, either in-phase or anti-phase synchronization can occur.
Interfacial effects in electromagnetic coupling within piezoelectric phononic crystals
Institute of Scientific and Technical Information of China (English)
F. J. Sabina; A. B. Movchan
2009-01-01
In this paper, we discuss waves in piezoelectric periodic composite, with the emphasis on the connection between the electromechanical coupling and the effects of dispersion of Bloch-Floquet waves. A particular attention is given to structures containing interfaces between dissimi-lar media and localization of the electrical fields near such interfaces.
Effective Hamiltonian for non-minimally coupled scalar fields
Mese, Emine; Pirinccioglu, Nurettin; Acikgoz, Irfan; Binbay, Figen
2006-01-01
Performing a relativistic approximation as the generalization to a curved spacetime of the flat space Klein-Gordon equation, an effective Hamiltonian which includes non-minimial coupling between gravity and scalar field and also quartic self-interaction of scalar field term is obtained.
The Effect of Job Displacement on Couples? Fertility Decisions
Huttunen, Kristiina; Kellokumpu, Jenni
2012-01-01
This paper analyzes the effects of job displacement on fertility using Finnish longitudinal employer-employee data (FLEED) matched to birth records. We distinguish between male and female job losses. We focus on couples where one spouse has lost his/her job due to a plant closure or mass layoff and follow them for several years both before and following the job loss. As a comparison group we use similar couples that were not affected by job displacement. In order to examine the possible chann...
Cotunneling Drag Effect in Coulomb-Coupled Quantum Dots
Keller, A. J.; Lim, J. S.; Sánchez, David; López, Rosa; Amasha, S.; Katine, J. A.; Shtrikman, Hadas; Goldhaber-Gordon, D.
2016-08-01
In Coulomb drag, a current flowing in one conductor can induce a voltage across an adjacent conductor via the Coulomb interaction. The mechanisms yielding drag effects are not always understood, even though drag effects are sufficiently general to be seen in many low-dimensional systems. In this Letter, we observe Coulomb drag in a Coulomb-coupled double quantum dot and, through both experimental and theoretical arguments, identify cotunneling as essential to obtaining a correct qualitative understanding of the drag behavior.
Rodríguez Rodríguez, Javier; Martínez Bazán, Carlos; Montañés García, José Luis
2003-01-01
A new method has been developed to measure experimentally the break-up properties of bubbles. The technique is based on the application of a particle tracking velocimetry algorithm to high-speed video images not only to measure the velocity of the bubbles, but also to detect the break-up events. Thus the algorithm is able to associate every broken bubble with the daughter bubbles formed upon their corresponding break-up. Moreover, the lifetime, as well as the number and size of fragments resu...
Study on the breakup lengths of free round liquid jets
Institute of Scientific and Technical Information of China (English)
ZHU Ying; WAN Yun-xia; HUANG Yong; PENG Xin-ke
2007-01-01
An experiment was conducted to measure the breakup lengths of water jets with a high-speed video camera for Weber numbers from 0 to about 1.1 × 103. The initial jet diameters are changed from 0.3mm to 1.0mm. The results indicate that at low jet velocity the breakup lengths of the jets are increased linearly from 0 to a maximum value. At the Weber number about 20 the breakup length of the jet reaches its maximum value for different initial jet diameter. A computation based on the dispersion equation is conducted to study the relationship between the growth rate of the jet surface wave and the maximum breakup length. The computations show that the maximum growth rate for the axisymmetric surface wave has a turning point at Weber number about 20, and that agrees well with the experiments.
Capillary Breakup of a Liquid Bridge: Identifying Regimes and Transitions
Li, Yuan
2016-01-01
Computations of the breakup of a liquid bridge are used to establish the limits of applicability of similarity solutions derived for different breakup regimes. These regimes are based on particular viscous-inertial balances, that is different limits of the Ohnesorge number $Oh$. To accurately establish the transitions between regimes, the minimum bridge radius is resolved through four orders of magnitude using a purpose-built multiscale finite element method. This allows us to construct a quantitative phase diagram for the breakup phenomenon which includes the appearance of a recently discovered low-$Oh$ viscous regime. The method used to quantify the accuracy of the similarity solutions allows us to identify a number of previously unobserved features of the breakup, most notably an oscillatory convergence towards the viscous-inertial similarity solution. Finally, we discuss how the new findings open up a number of challenges for both theoretical and experimental analysis.
Effect of temperature coupling on ozone depletion prediction
Chandra, S.; Butler, D. M.; Stolarski, R. S.
1978-01-01
The effects of chlorine perturbations on both the temperature and the ozone distribution in the stratosphere have been studied using a simplified radiative-photochemical model. The model solves the hydrostatic equation for total density in a self-consistent manner as the temperature is changed. Radiative coupling is found to have a significant effect on both the thermal structure and the ozone distribution, particularly in the 35-50-km region. By increasing the ClX mixing ratio by 5.0 ppbv, the temperature in this region is decreased by 5 to 10 K with a slight increase below 30 km. The local ozone depletion around 40 km due to added ClX is smaller compared with the estimate made by keeping the temperature fixed to the ambient condition. However, the integrated effect of radiative coupling is to increase the calculated column ozone depletion by 15% to 25% in this model.
Breakup and coalescence characteristics of a hollow cone swirling spray
Saha, Abhishek; Lee, Joshua D.; Basu, Saptarshi; Kumar, Ranganathan
2012-12-01
This paper deals with an experimental study of the breakup characteristics of water emanating from hollow cone hydraulic injector nozzles induced by pressure-swirling. The experiments were conducted using two nozzles with different orifice diameters 0.3 mm and 0.5 mm and injection pressures (0.3-4 MPa) which correspond to Rep = 7000-26 000. Two types of laser diagnostic techniques were utilized: shadowgraph and phase Doppler particle anemometry for a complete study of the atomization process. Measurements that were made in the spray in both axial and radial directions indicate that both velocity and average droplet diameter profiles are highly dependent on the nozzle characteristics, Weber number and Reynolds number. The spatial variation of diameter and velocity arises principally due to primary breakup of liquid films and subsequent secondary breakup of large droplets due to aerodynamic shear. Downstream of the nozzle, coalescence of droplets due to collision was also found to be significant. Different types of liquid film breakup were considered and found to match well with the theory. Secondary breakup due to shear was also studied theoretically and compared to the experimental data. Coalescence probability at different axial and radial locations was computed to explain the experimental results. The spray is subdivided into three zones: near the nozzle, a zone consisting of film and ligament regime, where primary breakup and some secondary breakup take place; a second zone where the secondary breakup process continues, but weakens, and the centrifugal dispersion becomes dominant; and a third zone away from the spray where coalescence is dominant. Each regime has been analyzed in detail, characterized by timescale and Weber number and validated using experimental data.
Vibrating Breakup of Jet for Uniform Metal Droplets
Institute of Scientific and Technical Information of China (English)
Shengdong GAO; Yingxue YAO; Chengsong CUI
2007-01-01
Uniform droplet formation from capillary stream breakup provides promising opportunities for many applications such as solder balls manufacturing, circuit board printing and rapid prototype manufacturing. In this study an apparatus capable of making monosize metal spheres by vibrating breakup has been developed. The droplets were electrically charged to avoid collision and merging with one another during flight. As a result, uniformly sized tin powders (180μm in diameter) were obtained after cooling and solidification.
Directory of Open Access Journals (Sweden)
Ali Akbar Soleimani
2015-07-01
Full Text Available Background: The purpose of this investigation is to determine the efficacy of emotionally focused couples therapy (EFT-C on enhancement of marital adjustment in infertile couples. Materials and Methods: This was a semi-experimental study with a pre- and post-test design. We selected 30 infertile couples (60 subjects by purposive sampling. Couples were randomly assigned to two groups, sample and control. Each group consisted of 15 couples who had marital maladjustment and low sexual satisfaction. Couples answered the marital adjustment and sexual satisfaction questionnaires at baseline after which the sample group received 10 sessions of EFT-C. Results: Results of pre-test and post-test showed that EFT-C significantly impacted marital adjustment and sexual satisfaction. Conclusion: EFT-C had a significant effect on enhancement of satisfaction, cohesion and affectional expression. This approach impacted physical and emotional sexual satisfaction of infertile couples.
Closed system of coupling effects in generalized thermo-elastoplasticity
Śloderbach, Z.
2016-05-01
In this paper, the field equations of the generalized coupled thermoplasticity theory are derived using the postulates of classical thermodynamics of irreversible processses. Using the Legendre transformations two new thermodynamics potentials P and S depending upon internal thermodynamic forces Π are introduced. The most general form for all the thermodynamics potentials are assumed instead of the usually used additive form. Due to this assumption, it is possible to describe all the effects of thermomechanical couples and also the elastic-plastic coupling effects observed in such materials as rocks, soils, concretes and in some metalic materials. In this paper not only the usual postulate of existence of a dissipation qupotential (the Gyarmati postulate) is used to derive the velocity equation. The plastic flow constitutive equations have the character of non-associated flow laws even when the Gyarmati postulate is assumed. In general formulation, the plastic strain rate tensor is normal to the surface of the generalized function of plastic flow defined in the the space of internal thermodynamic forces Π but is not normal to the yield surface. However, in general formulation and after the use the Gyarmati postulate, the direction of the sum of the plastic strain rate tensor and the coupled elastic strain rate tensor is normal to the yield surface.
Reactive Coupling Effects on Amplitude Death of Coupled Limit-Cycle Systems
Institute of Scientific and Technical Information of China (English)
WANG Jin-Hua; LI Xiao-Wen
2009-01-01
Amplitude death in coupled limit-cycle systems induced by the reactive coupling is studied. The presence of reactive coupling parameter changes the amplitude death process of the system,and increases the critical coupling strength for the emergence of amplitude death.When the systems are in the state of complete or partial amplitude death,increasing the reactive coupling will increase the number of partial synchronization groups,implying the increase of disorder of the system.Increasing the reactive coupling makes the elimination of the amplitude death of the systems harder.
Effective field theory of quantum gravity coupled to scalar electrodynamics
Ibiapina Bevilaqua, L.; Lehum, A. C.; da Silva, A. J.
2016-05-01
In this work, we use the framework of effective field theory to couple Einstein’s gravity to scalar electrodynamics and determine the renormalization of the model through the study of physical processes below Planck scale, a realm where quantum mechanics and general relativity are perfectly compatible. We consider the effective field theory up to dimension six operators, corresponding to processes involving one-graviton exchange. Studying the renormalization group functions, we see that the beta function of the electric charge is positive and possesses no contribution coming from gravitational interaction. Our result indicates that gravitational corrections do not alter the running behavior of the gauge coupling constants, even if massive particles are present.
Magnetoelectric coupling effects in multiferroic complex oxide composite structures.
Vaz, Carlos A F; Hoffman, Jason; Ahn, Charles H; Ramesh, Ramamoorthy
2010-07-20
The study of magnetoelectric materials has recently received renewed interest, in large part stimulated by breakthroughs in the controlled growth of complex materials and by the search for novel materials with functionalities suitable for next generation electronic devices. In this Progress Report, we present an overview of recent developments in the field, with emphasis on magnetoelectric coupling effects in complex oxide multiferroic composite materials. PMID:20414887
Effective Supergravity from the Weakly Coupled HeteroticString
Energy Technology Data Exchange (ETDEWEB)
Gaillard, Mary K.
2005-05-01
The motivation for Calabi-Yau-like compactifications of the weakly coupled E{sub 8} {circle_times} E{sub 8} heterotic string theory, its particle spectrum and the issue of dilaton stabilization are briefly reviewed. Modular invariant models for hidden sector condensation and supersymmetry breaking are described at the quantum level of the effective field theory. Their phenomenological and cosmological implications, including a possible origin for R-parity, are discussed.
Effect of reactive feedback on the transverse mode coupling instability
International Nuclear Information System (INIS)
An important and realistic test to examine the effect of reactive feedback on the transverse mode coupling instability could be performed at PEP using the existing feedback system with some minor modifications. This test would of necessity take place at low energy and low synchrotron tune. Such an experiment is of great importance for the design of the LEP reactive feedback system and for the ultimate evaluation of LEP performance
Extracting electric dipole breakup cross section of one-neutron halo nuclei from breakup observables
Yoshida, Kazuki; Minomo, Kosho; Ogata, Kazuyuki
2014-01-01
How to extract an electric dipole (E1) breakup cross section \\sigma(E1) from one- neutron removal cross sections measured by using 12C and 208Pb targets, \\sigma_(-1n)^C and \\sigma_(-1n)^Pb, respectively, is discussed. It is shown that within about 5% error, \\sigma(E1) can be obtained by subtracting \\Gamma \\sigma_(-1n)^C from \\sigma_(- 1n)^Pb, as assumed in preceding studies. However, for the reaction of weakly-bound projectiles, the scaling factor \\Gamma is found to be two times as large as that usually adopted. As a result, we obtain 13-20% smaller \\sigma(E1) of 31Ne at 250 MeV/nucleon than extracted in a previous analysis of experimental data. By compiling the values of \\Gamma obtained for several projectiles, \\Gamma=(2.30 +/- 0.41)\\exp(- S_n)+(2.43 +/- 0.21) is obtained, where S_n is the neutron separation energy. The target mass number dependence of the nuclear parts of the one-neutron removal cross section and the elastic breakup cross section is also investigated.
Coulomb dissociation and momentum distributions for 11Li → 9Li + n + n breakup reactions
International Nuclear Information System (INIS)
Momentum distributions for the 11Li → 9Li+n+n breakup reaction, generated by Coulomb dipole excitations, axe calculated in a 3-body model for 11Li. The relative momentum distribution of the two neutrons is in good agreement with recent 3-body coincidence measurements but the momentum distribution for the 9Li recoil and the decay energy spectrum are much narrower than observed. These discrepancies may be due to higher order dynamical effects which have been ignored
HSIAO, Chao-Tsung; Chahine, Georges L.
2013-01-01
A simplified three-dimensional (3-D) zero-thickness shell model was developed to recover the non-spherical response of thick-shelled encapsulated microbubbles subjected to ultrasound excitation. The model was validated by comparison with previously developed models and was then used to study the mechanism of bubble break-up during non-spherical deformations resulting from the presence of a nearby rigid boundary. The effects of the shell thickness and the bubble standoff distanc...
On the Effects of Coupled Scalar Fields on Structure Formation
Li, Baojiu
2010-01-01
A coupling between a scalar field (representing the dark energy) and dark matter could produce rich phenomena in cosmology. It affects cosmic structure formation mainly through the fifth force, a velocity-dependent force that acts parallel to particle's direction of motion and proportional to its speed, an effective rescaling of the particle masses, and a modified background expansion rate. In many cases these effects entangle and it is difficult to see which is the dominant one. Here we perform N-body simulations to study their qualitative behaviour and relative importance in affecting the key structure formation observables, for a model with exponential scalar field coupling. We find that the fifth force, a prominent example of the scalar-coupling effects, is far less important than the rescaling of particle mass or the modified expansion rate. In particular, the rescaling of particle masses is shown to be the key factor leading to less concentration of particles in halos than in LCDM, a pattern which is al...
Coulomb versus nuclear break-up of sup 1 sup 1 Be halo nucleus in a nonperturbative framework
Fallot, M; Lacroix, D; Chomaz, P; Margueron, J
2002-01-01
The sup 1 sup 1 Be break-up is calculated at 41 MeV per nucleon incident energy on different targets using a nonperturbative time-dependent quantum calculation. The evolution of the neutron halo wave function shows an emission of neutron at large angles for grazing impact parameters and at forward angles for large impact parameters. The neutron angular distribution is deduced for the different targets and compared to experimental data. We emphasize the diversity of diffraction mechanisms, in particular we discuss the interplay of the nuclear effects such as the towing mode and the Coulomb break-up. A good agreement is found with experimental data.
International Nuclear Information System (INIS)
The studies on the breakup effects of weakly bound nuclei, both stable and radioactive, on fusion cross section is a subject of contemporary interest. These weakly bound nuclei have low breakup threshold (binding energy) that makes the fusion induced by these nuclei fundamentally different from that induced by tightly bound nuclei. Among these nuclei, the nucleus 9Be is very interesting because it has low break up threshold of 1.67 MeV and has a possible three body n+α+α Borromean structure. So far, numbers of experiments have been carried out to study the fusion reactions induced by 9Be on various targets at near barrier energies
Equivalence of post and prior sum rules for inclusive breakup reactions
International Nuclear Information System (INIS)
A critical examination of sum rules derived previously by Austern and Vincent (post form) and by Udagawa and Tamura (prior form) demonstrates that agreement between the two approaches is obtained if certain approximations implicit in the Udagawa-Tamura prior-form derivation are avoided. We examine the relation of the two approaches to singularities of the post-form distorted wave Born approximation matrix element and to the procedures for reduction of a many-body theory by use of effective operators in a model space. The two-step heuristic model is seen to be invalid for prior-form inelastic breakup; it is necessary to take account of nuclear excitations during projectile breakup. Careful treatment of the non-Hermiticity of kinetic energy operators with respect to continuum wave functions is required
Unsteady coupling effects of wet steam in steam turbines flows
International Nuclear Information System (INIS)
In addition to conventional turbomachinery problems, both the behavior and performances of steam turbines are highly dependent on the vapour thermodynamic state and the presence of a liquid phase. EDF, the main French electricity producer, is interested in further developing its' modelling capabilities and expertise in this area to allow for operational studies and long-term planning. This PhD thesis explores the modelling of wetness formation and growth in a steam turbine and an analysis of the coupling between the liquid phase and the main flow unsteadiness. To this end, the work in this thesis took the following approach. Wetness was accounted for using a homogeneous model coupled with transport equations to take into account the effects of non-equilibrium phenomena, such as the growth of the liquid phase and nucleation. The real gas attributes of the problem demanded adapted numerical methods. Before their implementation in the 3D elsA solver, the accuracy of the chosen models was tested using a developed one-dimensional nozzle code. In this manner, various condensation models were considered, including both poly-dispersed and monodispersed behaviours of the steam. Finally, unsteady coupling effects were observed from several perspectives (1D, 1D - 3D, 3D), demonstrating the ability of the method of moments to sustain unsteady phenomena which were not apparent in a simple monodispersed model. (author)
Coupling effect of quantum wells on band structure
International Nuclear Information System (INIS)
The coupling effects of quantum wells on band structure are numerically investigated by using the Matlab programming language. In a one dimensional finite quantum well with the potential barrier V0, the calculation is performed by increasing the number of inserted barriers with the same height Vb, and by, respectively, varying the thickness ratio of separated wells to inserted barriers and the height ratio of Vb to V0. Our calculations show that coupling is strongly influenced by the above parameters of the inserted barriers and wells. When these variables change, the width of the energy bands and gaps can be tuned. Our investigation shows that it is possible for quantum wells to achieve the desired width of the bands and gaps. (paper)
Middle-High Latitude N2O Distributions Related to the Arctic Vortex Breakup
Institute of Scientific and Technical Information of China (English)
无
2006-01-01
The relationship of N2O distributions with the Arctic vortex breakup is first analyzed with a probability distribution function (PDF) analysis. The N2O concentration shows different distributions between the early and late vortex breakup years. In the early breakup years, the N2O concentration shows low values and large dispersions after the vortex breakup, which is related to the inhomogeneity in the vertical advection in the middle and high latitude lower stratosphere. The horizontal diffusion coefficient (Kyy)shows a larger value accordingly. In the late breakup years, the N2O concentration shows high values and more uniform distributions than in the early years after the vortex breakup, with a smaller vertical advection and Kyy after the vortex breakup. It is found that the N2O distributions are largely affected by the Arctic vortex breakup time but the dynamically defined vortex breakup time is not the only factor.
Microscopic effective reaction theory for direct nuclear reactions
Directory of Open Access Journals (Sweden)
Ogata Kazuyuki
2016-01-01
Full Text Available Some recent activities with the microscopic effective reaction theory (MERT on elastic, inelastic, breakup, transfer, and knockout processes are reviewed briefly. As a possible alternative to MERT, a description of elastic and inelastic scattering with the continuum particle-vibration coupling (cPVC method is also discussed.
Dynamics of bubble breakup at a T junction
Lu, Yutao; Fu, Taotao; Zhu, Chunying; Ma, Youguang; Li, Huai Z.
2016-02-01
The gas-liquid interfacial dynamics of bubble breakup in a T junction was investigated. Four regimes were observed for a bubble passing through the T junction. It was identified by the stop flow that a critical width of the bubble neck existed: if the minimum width of the bubble neck was less than the critical value, the breakup was irreversible and fast; while if the minimum width of the bubble neck was larger than the critical value, the breakup was reversible and slow. The fast breakup was driven by the surface tension and liquid inertia and is independent of the operating conditions. The minimum width of the bubble neck could be scaled with the remaining time as a power law with an exponent of 0.22 in the beginning and of 0.5 approaching the final fast pinch-off. The slow breakup was driven by the continuous phase and the gas-liquid interface was in the equilibrium stage. Before the appearance of the tunnel, the width of the depression region could be scaled with the time as a power law with an exponent of 0.75; while after that, the width of the depression was a logarithmic function with the time.
Persistent and Coupling Current Effects in the LHC Superconducting Dipoles
Amet, S; Granata, V; Le Naour, S; Mishra, R K; Oberli, L R; Richter, D; Sanfilippo, S; Verweij, A P; Walckiers, L; Wolf, R
2003-01-01
One of the main issues for the operation of the LHC accelerator at CERN is the field errors generated by persistent and coupling currents in the main dipoles at injection conditions, i.e., 0.54Â T dipole field. For this reason we are conducting systematic magnetic field measurements to quantify the above effects and compare them to the expected values from measurement on strands and cables. We discuss the results in terms of DC effects from persistent current magnetization, AC effects with short time constant from strand and cable coupling currents, and long-term decay during constant current excitation. Average and spread of the measured field errors over the population of magnets tested are as expected or smaller. Field decay at injection, and subsequent snap-back, show for the moment the largest variation from magnet to magnet, with weak correlation to parameters that can be controlled during production. For this reason these effects are likely to result in the largest spread of field errors over the who...
Effective method for calculation of the analytic QCD coupling constant
Alekseev, A Yu
2002-01-01
The analytic running coupling of strong interaction alpha sub a sub n for initial standard perturbative approximations up to three-loop order is studied. The nonperturbative contributions to alpha sub a sub n are obtained in an explicit form. They are shown to be represented in the form of the expansion in the inverse powers of Euclidean momentum squared. It is shown that two-loop and three-loop-order corrections result in partial compensation of one-loop-order leading in the ultraviolet region nonperturbative contribution of the form 1/q sup 2. On basis of the stated expansion the effective method for calculation of the analytic running coupling is developed for all q > LAMBDA. The comparative analysis of the perturbative and nonperturbative contributions is carried out in the momentum dependence of alpha sub a sub n and its perturbative component for one - three-loop cases leads to a conclusion on higher loop stability of the analytic running coupling and its low dependence on the n sub f -threshold matchin...
Lithosphere erosion and breakup due to the interaction between extension and plume upwelling
Lavecchia, Alessio; Thieulot, Cedric; Beekman, Fred; Cloetingh, Sierd; Clark, Stuart
2016-04-01
We have built up 2D numerical models of coupled crust - lithospheric mantle - upper mantle systems. The reconstructed sections are subjected to external velocity fields and mantle plume impingement beneath the lithosphere, both acting simultaneously. The models are designed to simulate the interaction between plumes and lithosphere in an extensional setting with the main purpose to contribute to address the following questions: 1) Are plumes capable of weakening certain lithospheric regions? Where and when are the main effects observed? 2a) Can a plume really cause a plate break-off and drifting with no external contribution; 2b) if yes, are there any particularly favorable conditions required? In our models a novel aspect is melt generation due to plume, upper mantle and lithospheric mantle partial melting. Produced melts are capable to ascend across the reconstructed sections due to buoyancy. Furthermore, heat transport related to melt movement is taken into account and leads to a significant heating of host rocks at the melt neutral buoyancy depth. In absence of external stress or velocity fields, the effects of plume impingement beneath the lithosphere are negligible at surface. Here the main observed feature is the production of doming at various length scales, depending on the adopted rheology for the crust. At depth, the main effect is a thermo-mechanical erosion of the lithospheric mantle with production of melts and subsequent underplating of the crust. The heat flux due to plume impingement and crust underplating determines a weakening of crust and lithosphere. However, the strength drop is not followed by an appreciable deformation. When external stress or velocity fields are applied, the coupled effects with plume presence and melt production lead to great modifications of the lithospheric structure. Topography profiles are characterized by the presence of a horst and graben structure, and extensive erosion of the lithosphere always occurs. The presence
Rapid three-dimensional passive rotation micromixer using the breakup process
Park, Sung-Jin; Kim, Jung Kyung; Park, Junha; Chung, Seok; Chung, Chanil; Chang, Jun Keun
2004-01-01
Stretching and folding, diffusion, and breakup are three basic processes that occur while mixing fluids. Although stretching and folding the interface of two fluids by rotation enables the mixing at microscale level in both low and high Reynolds number flows, rotation is not as effective at a low Reynolds number as at a high Reynolds number. Therefore, developing a rapid micromixer for microfluidic systems that can be used at a low Reynolds number is a challenging task, because it can demonstrate the full potential of microfluidic systems in commercial markets. Here, to enhance the mixing efficiency of a micromixer based on passive rotation, we present a breakup method. The breakup method not only generates interface actively but also enhances the diffusion process at the interface. With our novel design, over 70% mixing can be achieved only after passing through a 4 mm long microchannel. In this work, the mixer was easily fabricated with polydimethylsiloxane by soft lithography and a self-aligned bonding method with methanol. We analyzed the flow in the micromixer using the computational fluid dynamics method. Also, we conducted quantitative analyses using a confocal scanning microscope and image processing.
Quantum Effects of Mesoscopic Inductance and Capacity Coupling Circuits
Institute of Scientific and Technical Information of China (English)
LIU Jian-Xin; AN Zhan-Yuan; SONG Yong-Hua
2006-01-01
Using the quantum theory for a mesoscopic circuit based on the discretenes of electric charges, the finitedifference Schrodinger equation of the non-dissipative mesoscopic inductance and capacity coupling circuit is achieved.The Coulomb blockade effect, which is caused by the discreteness of electric charges, is studied. Appropriately choose the components in the circuits, the finite-difference Schrodinger equation can be divided into two Mathieu equations in p representation. With the WKBJ method, the currents quantum fluctuations in the ground states of the two circuits are calculated. The results show that the currents quantum zero-point fluctuations of the two circuits are exist and correlated.
DRAG REDUCTION EFFECT OF COUPLING FLEXIBLE TUBES WITH TURBULENT FLOW
Institute of Scientific and Technical Information of China (English)
CAI Shu-peng; JIN Guo-yu; LI Da-mei; Yang Lin
2008-01-01
To analyze the mechanism of drag reducing effect by coupling flexible tubes with turbulent flow, based on experimental examination of more obvious turbulent drag reduction effect in flexible tubes than in rigid tubes, experimental investigation was performed on the effect of turbulent drag reduction, fluctuating vibration characteristics of flexible tube and the correlations by using a double-tube system and laser displacement sensor. The results are as follows: with the decrease of the thickness of the flexible tubes, the root mean square of fluctuating amplitude of the outer wall of the tubes increases, and the non-dimensional burst period increases, resulting in the increase of the reduction rate of drag coefficient by coupling flexible tubes with turbulent flow. At applied pressure-balanced air on the outer wall and the Reynolds number of about 1.75 104, the non-dimensional burst periods of the flexible tubes with the thickness of 2 mm, 3 mm, 4 mm are 141, 126, 105, respectively.
Breakup of Droplets in Micro and Nanofluidic T-Junctions
Directory of Open Access Journals (Sweden)
A. bedram
2013-01-01
Full Text Available We employ numerical simulations to investigate the breakup of droplets in micro- and nanoscale T junctions, which are used to produce small droplets from a large droplet. For this purpose a Volume f Fluid (VOF based method is used and for verifying the reliability of the numerical outcomes, the results are compared with the available experimental and analytical results. Our results reveal that breakup time and breakup length of the droplets play important roles in handling these systems optimally. Our results also indicate that for nanoscale Tjunctions by increasing the capillary number the performance increases while for the micro-scale systems there is a specific capillary number for which the system is in its optimum condition.
Coulomb and Nuclear Breakup at Low Energies: Scaling Laws
Directory of Open Access Journals (Sweden)
Hussein M. S.
2013-12-01
Full Text Available We report on a recent work on the low-energy behavior of the breakup cross section in so far as it has important role in the fusion of weakly bound and halo nuclei at near-barrier energies. We assess the way the nuclear component of this cross section scales with the target mass. In complete accord with previous finding at higher energies we verify that the low energy behavior of the breakup cross section for a given projectile and relative center of mass energy with respect to the Coulomb barrier height scales as the cubic root of the mass number of the target. Surprisingly we find that the Coulomb component of the breakup cross section at these low energies also obeys scaling, but with a linear dependence on the target charge. Our findings are important when planning for experiments involving these exotic nuclei.
Break-up stage restoration in multifragmentation reactions
Energy Technology Data Exchange (ETDEWEB)
Raduta, Ad.R. [Institut de Physique Nucleaire, IN2P3-CNRS, F-91406 Orsay cedex (France)]|[NIPNE, Bucharest-Magurele, POB-MG 6 (Romania); Bonnet, E.; Borderie, B.; Le Neindre, N.; Rivet, M.F. [Institut de Physique Nucleaire, IN2P3-CNRS, F-91406 Orsay cedex (France); Piantelli, S. [Dip. di Fisica e Sezione INFN, Universita di Firenze, I-50019 Sesto Fiorentino, Fi (Italy)
2007-02-15
In the case of Xe+Sn at 32 MeV/nucleon multifragmentation reaction break-up fragments are built-up from the experimentally detected ones using evaluations of light particle evaporation multiplicities which thus settle fragment internal excitation. Freeze-out characteristics are extracted from experimental kinetic energy spectra under the assumption of full decoupling between fragment formation and energy dissipated in different degrees of freedom. Thermal kinetic energy is determined uniquely while for freeze-out volume - collective energy a multiple solution is obtained. Coherence between the solutions of the break-up restoration algorithm and the predictions of a multifragmentation model with identical definition of primary fragments is regarded as a way to select the true value. The broad kinetic energy spectrum of {sup 3}He is consistent with break-up genesis of this isotope. (authors)
Significance Of Deuteron Breakup In A Halo Transfer Reaction
Yilmaz, M; Yilmaz, Mustafa; Gonul, Bulent
2000-01-01
We discuss the quasi-adiabatic approximations to the three-body wavefunction in breakup processes, clarifying the assumptions underlying the model. This suggests alternative approximation schemes. Using different theoretical three-body models, calculated differential cross section angular distributions for the Be-11(p,d) reaction,for which new preliminary data have been reported at 35 MeV, are presented. We show that calculations are sensitive to the inclusion of deuteron breakup and to the breakup model used, particularly if used to deduce absolute spectroscopic information on the 0{+} and 2{+} Be-10 core state parentages. There is also considerable sensitivity to the model used in calculations of the relative cross sections to the two states.
Scaling laws for near barrier Coulomb and Nuclear Breakup
Hussein, M S; Lubian, J; Otomar, D R; Canto, L F
2013-01-01
We investigate the nuclear and the Coulomb contributions to the breakup cross sections of $^6$Li in collisions with targets in different mass ranges. Comparing cross sections for different targets at collision energies corresponding to the same $E/V_{\\mathrm{\\scriptscriptstyle B}}$, we obtain interesting scaling laws. First, we derive an approximate linear expression for the nuclear breakup cross section as a function of $A_{\\mathrm{% \\scriptscriptstyle T}}^{1/3}$. We then confirm the validity of this expression performing CDCC calculations. Scaling laws for the Coulomb breakup cross section are also investigated. In this case, our CDCC calculations indicate that this cross section has a linear dependence on the atomic number of the target. This behavior is explained by qualitative arguments. Our findings, which are consistent with previously obtained results for higher energies, are important when planning for experiments involving exotic weakly bound nuclei.
Mechanisms of Li-projectile breakup-up
International Nuclear Information System (INIS)
Various experimental and theoretical features observed in recent studies of break-up of 6Li and 7Li projectiles in the field of atomic nuclei are discussed, in particular for the transitional energy regime of 10-30 MeV/amu. The discussion is organized as three independent lectures presented at the International School on Nuclear Physics, Kiev (UkSSR), 28 May - 8 June, 1990. After a survey on the main experimental facts and on the basic reaction mechanisms, current theoretical approaches are illustrated by an application to the analysis of elastic break-up of 156 MeV 6Li projectiles. Finally Coulomb break-up is discussed as a novel tool of laboratory nuclear astrophysics. (orig.)
Experimental Investigation on Breakup of Ice Floe on Waves
Institute of Scientific and Technical Information of China (English)
WANG Yongxue; LI Chunhua; LI Guangwei; SHEN Zhaowei
2000-01-01
Experimental investigation of ice floe breakup on waves by use of non-refrigerated breakable materials has been carried out. The incident wave heights for breakup of ice floe with different lengths, and the influence of rigidity on reflection and transmission coefficients are discussed. The experimental results show that the ratio of the ice floe length, Li, to the wavelength, L, is one of the significant factor affecting the minimum wave height to cause fracture of ice floe, and another key factor is the ratio of the ice floethickness, hi and Li.
On the breakup of tectonic plates by polar wandering
Liu, H.-S.
1974-01-01
The equations for the stresses in a homogeneous shell of uniform thickness caused by a shift of the axis of rotation are derived. The magnitude of these stresses reaches a maximum value of the order of 10 to the 9th power dyn/sq cm, which is sufficient for explaining a tectonic breakup. In order to deduce the fracture pattern according to which the breakup of tectonic plates can be expected the theory of plastic deformation of shells is applied. The analysis of this pattern gives an explanation of the existing boundary systems of the major tectonic plates as described by Morgan (1968), LePichon (1968) and Isacks et al. (1968).
Jeanniot, L.; Kusznir, N. J.; Mohn, G.; Manatschal, G.
2014-12-01
How the lithosphere and asthenosphere deforms during continental rifting leading to breakup and sea-floor spreading initiation is poorly understood. Observations at present-day and fossil analogue rifted margins show a complex OCT architecture which cannot be explained by a single simplistic lithosphere deformation modes. This OCT complexity includes hyper-extended continental crust and lithosphere, detachments faults, exhumed mantle, continental slivers and scattered embryonic oceanic crust. We use a coupled kinematic-dynamic model of lithosphere and asthenosphere deformation to determine the sequence of lithosphere deformation modes leading to continental breakup for Iberia-Newfoundland conjugate margin profiles. We quantitatively calibrate the models using observed present-day water loaded subsidence and crustal thickness, together with subsidence history and the age of melt generation. Flow fields, representing a sequence of lithosphere deformation modes, are generated by a 2D finite element viscous flow model (FE-Margin), and used to advect lithosphere and asthenosphere temperature and material. FE-Margin is kinematically driven by divergent deformation in the upper 15-20 km of the lithosphere inducing passive upwelling below. Buoyancy enhanced upwelling (Braun et al. 2000) is also kinematically included. Melt generation by decompressional melting is predicted using the methodology of Katz et al., 2003. The extension magnitudes used in the lithosphere deformation models are taken from Sutra et al (2013). The best fit calibrated models of lithosphere deformation evolution for the Iberia-Newfoundland conjugate margins require (i) an initial broad region of lithosphere deformation and passive upwelling, (ii) lateral migration of deformation, (iii) an increase in extension rate with time, (iv) focussing of deformation and (v) buoyancy induced upwelling. The preferred calibrated models predict faster extension rates and earlier continental crustal rupture and
On plasma coupling and turbulence effects in low velocity stopping
Energy Technology Data Exchange (ETDEWEB)
Kurilenkov, Yu K [Unified Institute for High Temperatures of Russian Academy of Sciences, 13/19 Izhorskaya Str., 125412 Moscow (Russian Federation); Maynard, G [Laboratoire de Physique des Gaz et des Plasmas, UMR-8578, Bat. 210, Universite Paris XI, F-91405 Orsay (France); Barriga-Carrasco, M D [Laboratoire de Physique des Gaz et des Plasmas, UMR-8578, Bat. 210, Universite Paris XI, F-91405 Orsay (France); Valuev, A A [Unified Institute for High Temperatures of Russian Academy of Sciences, 13/19 Izhorskaya Str., 125412 Moscow (Russian Federation)
2006-04-28
The problem of stopping power (SP) for projectile ions is analysed in terms of the dielectric function and effective collision frequency for moderately dense and strongly coupled plasmas (SCP). We consider several issues regarding the calculation of stopping power for correlated ensembles of particles and oscillators. In particular, effects of group (few particle) modes, transition from positive to negative dispersion and excitation of collective modes up to suprathermal level at plasma targets are addressed. Linear SP of dense suprathermal (nonlinear) plasma targets at different levels of target plasma turbulence is estimated. The force of suprathermal plasma oscillations on the projectile ions is mostly in the nature of increased frictional drag. The results obtained show the possibility of increasing low velocity stopping (up to 'turbulent' values) in comparison with losses in equilibrium dense plasma targets. Experimental conditions to create specific turbulent targets as well as some connection between stopping phenomena and SCP transport properties are discussed briefly.
Coupled Simulations of RF Effects on Tearing Modes
International Nuclear Information System (INIS)
Full text: We present integrated feedback simulations of neoclassical tearing modes in tokamak plasmas. The implementation relies on the NIMROD and GENRAY codes, along with new codes for calculating a local quasilinear operator, and for performing the code coupling. The mathematical formulation relies on the formulation of a third-order electron drift-kinetic equation that captures the bootstrap current effects and is consistent with ECCD-driven kinetic distortion effects such as the Fisch-Boozer and Ohkawa current drives. Numerically solving the drift-kinetic equation relies on a new high-order continuum discretization scheme suitable for solving the equation in the presence of a macroscopic three-dimensional magnetic field. Implementing these new kinetic closures implicitly, along with the drift-kinetic terms, provides many numerical challenges and requires careful verification. (author)
Understanding Soliton Spectral Tunneling as a Spectral Coupling Effect
DEFF Research Database (Denmark)
Guo, Hairun; Wang, Shaofei; Zeng, Xianglong;
2013-01-01
Soliton eigenstate is found corresponding to a dispersive phase profile under which the soliton phase changes induced by the dispersion and nonlinearity are instantaneously counterbalanced. Much like a waveguide coupler relying on a spatial refractive index profile that supports mode coupling bet...... exactly implies phase as well as group-velocity matching between the input soliton and tunneled soliton, namely a soliton phase matching condition. Examples in realistic photonic crystal fibers are also presented.......Soliton eigenstate is found corresponding to a dispersive phase profile under which the soliton phase changes induced by the dispersion and nonlinearity are instantaneously counterbalanced. Much like a waveguide coupler relying on a spatial refractive index profile that supports mode coupling...... between channels, here we suggest that the soliton spectral tunneling effect can be understood supported by a spectral phase coupler. The dispersive wave number in the spectral domain must have a coupler-like symmetric profile for soliton spectral tunneling to occur. We show that such a spectral coupler...
Elastic and inelastic breakup of deuterons with energy below 100 MeV
Carlson, B V; Sin, M
2015-01-01
We present calculations of deuteron elastic and inelastic breakup cross sections and angular distributions at deuteron energies below 100 MeV obtained using the post-form DWBA approximation. The elastic breakup cross section was extensively studied in the past. Very few calculations of inelastic breakup have been performed, however. We also analyze the angular momentum - energy distributions of the cross section for formation of the compound nucleus after inelastic breakup.
Asymptotic and near-target direct breakup of 6Li and 7Li
Kalkal, Sunil; Simpson, E. C.; Luong, D. H.; Cook, K. J.; Dasgupta, M.; Hinde, D. J.; Carter, I. P.; Jeung, D. Y.; Mohanto, G.; Palshetkar, C. S.; Prasad, E.; Rafferty, D. C.; Simenel, C.; Vo-Phuoc, K.; Williams, E.; Gasques, L. R.; Gomes, P. R. S.; Linares, R.
2016-04-01
Background: Li,76 and 9Be are weakly bound against breakup into their cluster constituents. Breakup location is important for determining the role of breakup in above-barrier complete fusion suppression. Recent works have pointed out that experimental observables can be used to separate near-target and asymptotic breakup. Purpose: Our purpose is to distinguish near-target and asymptotic direct breakup of Li,76 in reactions with nuclei in different mass regions. Method: Charged particle coincidence measurements are carried out with pulsed Li,76 beams on 58Ni and 64Zn targets at sub-barrier energies and compared with previous measurements using 208Pb and 209Bi targets. A detector array providing a large angular coverage is used, along with time-of-flight information to give definitive particle identification of the direct breakup fragments. Results: In interactions of 6Li with 58Ni and 64Zn, direct breakup occurs only asymptotically far away from the target. However, in interactions with 208Pb and 209Bi, near-target breakup occurs in addition to asymptotic breakup. Direct breakup of 7Li into α -t is not observed in interactions with 58Ni and 64Zn. However, near-target dominated direct breakup was observed in measurements with 208Pb and 209Bi. A modified version of the Monte Carlo classical trajectory model code platypus, which explicitly takes into account lifetimes associated with unbound states, is used to simulate sub-barrier breakup reactions. Conclusions: Near-target breakup in interactions with Li,76 is an important mechanism only for the heavy targets 208Pb and 209Bi. There is insignificant near-target direct breakup of 6Li and no direct breakup of 7Li in reactions with 58Ni and 64Zn. Therefore, direct breakup is unlikely to suppress the above-barrier fusion cross section in reactions of Li,76 with 58Ni and 64Zn nuclei.
Matrix effects in inductively coupled plasma mass spectrometry
Energy Technology Data Exchange (ETDEWEB)
Chen, Xiaoshan
1995-07-07
The inductively coupled plasma is an electrodeless discharge in a gas (usually Ar) at atmospheric pressure. Radio frequency energy generated by a RF power source is inductively coupled to the plasma gas through a water cooled load coil. In ICP-MS the {open_quotes}Fassel{close_quotes} TAX quartz torch commonly used in emission is mounted horizontally. The sample aerosol is introduced into the central flow, where the gas kinetic temperature is about 5000 K. The aerosol is vaporized, atomized, excited and ionized in the plasma, and the ions are subsequently extracted through two metal apertures (sampler and skimmer) into the mass spectrometer. In ICP-MS, the matrix effects, or non-spectroscopic interferences, can be defined as the type of interferences caused by dissolved concomitant salt ions in the solution. Matrix effects can be divided into two categories: (1) signal drift due to the deposition of solids on the sampling apertures; and/or (2) signal suppression or enhancement by the presence of the dissolved salts. The first category is now reasonably understood. The dissolved salts, especially refractory oxides, tend to deposit on the cool tip of the sampling cone. The clogging of the orifices reduces the ion flow into the ICP-MS, lowers the pressure in the first stage of ICP-MS, and enhances the level of metal oxide ions. Because the extent of the clogging increases with the time, the signal drifts down. Even at the very early stage of the development of ICP-MS, matrix effects had been observed. Houk et al. found out that the ICP-MS was not tolerant to solutions containing significant amounts of dissolved solids.
Breakup of New Orleans Households after Hurricane Katrina
Rendall, Michael S.
2011-01-01
Theory and evidence on disaster-induced population displacement have focused on individual and population-subgroup characteristics. Less is known about impacts on households. I estimate excess incidence of household breakup resulting from Hurricane Katrina by comparing a probability sample of pre-Katrina New Orleans resident adult household heads…
Approximations in fusion and breakup reactions induced by radioactive beams
Energy Technology Data Exchange (ETDEWEB)
Cardenas, W.H.Z.; Carlin Filho, N.; Hussein, M.S. [Sao Paulo Univ., SP (Brazil). Inst. de Fisica; Canto, L.F.; Donangelo, R. [Universidade Federal, Rio de Janeiro, RJ (Brazil). Inst. de Fisica; Lubian, J. [Universidade Federal Fluminense, Niteroi, RJ (Brazil). Inst. de Fisica; Centro de Aplicaciones Tecnologicas y Desarrollo Nuclear (CEADEN), Havana (Cuba); Romanelli, A. [Facultad de Ingenieria, Montevideo (Uruguay). Inst. de Fisica
2000-07-01
Some commonly used approximations for complete fusion and breakup transmission coefficients in collisions of weakly bound projectiles at near barrier energies are assessed. We show that they strongly depend on the adopted classical trajectory and can be significantly improved with proper treatment of the incident and emergent currents in the WKB approximation. (author)
Coupled effects of local movement and global interaction on contagion
Zhong, Li-Xin; Chen, Rong-Da; Qiu, Tian; Zhong, Chen-Yang
2014-01-01
By incorporating segregated spatial domain and individual-based linkage into the SIS (susceptible-infected-susceptible) model, we investigate the coupled effects of random walk and intragroup interaction on contagion. Compared with the situation where only local movement or individual-based linkage exists, the coexistence of them leads to a wider spread of infectious disease. The roles of narrowing segregated spatial domain and reducing mobility in epidemic control are checked, these two measures are found to be conducive to curbing the spread of infectious disease. Considering heterogeneous time scales between local movement and global interaction, a log-log relation between the change in the number of infected individuals and the timescale $\\tau$ is found. A theoretical analysis indicates that the evolutionary dynamics in the present model is related to the encounter probability and the encounter time. A functional relation between the epidemic threshold and the ratio of shortcuts, and a functional relation...
Quantum Plasmonics: Nonlocal effects in coupled nanowire dimer
Teperik, T V; Aizpurua, J; Borisov, A G
2013-01-01
The optical response of a coupled nanowire dimer is studied using a fully quantum mechanical approach. The translational invariance of the system allows to apply the time--dependent density functional theory for the plasmonic dimer with the largest size considered so far in quantum calculations. Detailed comparisons with results from classical electromagnetic calculations based on local and non local hydrodynamic response, as well as with results of the recently developed quantum corrected model is performed. We show that electron tunneling and dynamical screening are the major nonlocal quantum effects determining the plasmonic modes and field enhancement in the system. Account for the electron tunneling at small junction sizes allows semi-quantitative description of quantum results within classical framework. We also discuss the shortcomings of classical treatments using non-local dielectric permittivities based on hydrodynamic models. Finally, the implications of the actual position of the screening charge ...
Effective gravitational couplings for cosmological perturbations in generalized Proca theories
De Felice, Antonio; Kase, Ryotaro; Mukohyama, Shinji; Tsujikawa, Shinji; Zhang, Ying-li
2016-01-01
We consider the finite interactions of the generalized Proca theory including the sixth-order Lagrangian and derive the full linear perturbation equations of motion on the flat Friedmann-Lema\\^{i}tre-Robertson-Walker background in the presence of a matter perfect fluid. By construction, the propagating degrees of freedom (besides the matter perfect fluid) are two transverse vector perturbations, one longitudinal scalar, and two tensor polarizations. The Lagrangians associated with intrinsic vector modes neither affect the background equations of motion nor the second-order action of tensor perturbations, but they do give rise to non-trivial modifications to the no-ghost condition of vector perturbations and to the propagation speeds of vector and scalar perturbations. We derive the effective gravitational coupling $G_{\\rm eff}$ with matter density perturbations under a quasi-static approximation on scales deep inside the sound horizon. We find that the existence of intrinsic vector modes allows a possibility ...
Effects of nicardipine on ventriculo-arterial coupling in humans.
Tanaka, K; Oshita, S; Kitahata, H; Kimura, H; Kawahito, S; Park, Y C; Sakabe, T
1998-08-01
The ratio of effective arterial elastance (Ea) to left ventricular elastance (Ees) is an indicator of the coupling between ventricular properties and arterial load properties. Another criterion for the coupling between an energy source and its load is the principle of economical fuel consumption, or mechanical efficiency, which is defined as the ratio of stroke work (SW) to myocardial oxygen consumption per beat (MVO2). It has been revealed that SW of ventricular contraction is maximized when Ea/Ees = 1, while mechanical efficiency is maximized when Ea/Ees = 0.5. The purpose of the present study was to investigate the ventriculo-arterial coupling during hypertension, and the effects of nicardipine on this relationship in surgical patients using Ea/Ees and SW/MVO2 as indicators. Anaesthesia was maintained with isoflurane, nitrous oxide, and fentanyl. Radial artery pressure was displayed on a polygraph, and left ventricular end-systolic and end-diastolic volumes were determined by use of transoesophageal echocardiography. Ees was calculated as MAP/(ESVI-4), where MAP is mean arterial pressure and ESVI is end-systolic volume index. Ea was calculated as the ratio of MAP to stroke volume index (SVI). Stroke work index (SWI) was calculated as the product of MAP and SVI. MVO2 was assessed by estimating the ventricular pressure-volume area index (PVAI), which is expressed as the sum of SWI and the end-systolic potential energy index. Before (baseline), and 3, 10, 20, and 30 min after i.v. nicardipine (30 micrograms kg-1), Ea/Ees and SWI/PVAI were determined in 14 surgical patients with intraoperative hypertension. Before nicardipine (during hypertension), Ea was almost equal to Ees, whereas Ea/Ees was significantly reduced to about 0.5-0.6 at 3, 10, and 20 min after nicardipine. SWI/PVAI was maximized and significantly greater than the baseline value at 3 min after nicardipine. These results suggest that, during hypertension, ventricular and arterial properties were so
Robustness and breakup of the spiral wave in a two-dimensional lattice network of neurons
Institute of Scientific and Technical Information of China (English)
无
2010-01-01
The robustness and breakup of spiral wave in a two-dimensional lattice networks of neurons are investigated. The effect of small- world type connection is often simplified with local regular connection and the long-range connection with certain probability. The network effect on the development of spiral wave can be better described by local regular connection and changeable long-range connection probability than fixed long-range connection probability because the long-range probability could be changeable in realistic biological system. The effect from the changeable probability for long-range connection is simplified by multiplicative noise. At first, a stable rotating spiral wave is developed by using appropriate initial values, parameters and no-flux boundary conditions, and then the effect of networks is investigated. Extensive numerical studies show that spiral wave keeps its alive and robust when the intensity of multiplicative noise is below a certain threshold, otherwise, the breakup of spiral wave occurs. A statistical factor of synchronization in two-dimensional array is defined to study the phase transition of spiral wave by checking the membrane potentials of all neurons corresponding to the critical parameters(the intensity of noise or forcing current)in the curve for factor of synchronization. The Hindmarsh-Rose model is investigated, the Hodgkin-Huxley neuron model in the presence of the channel noise is also studied to check the model independence of our conclusions. And it is found that breakup of spiral wave is easier to be induced by the multiplicative noise in presence of channel noise.
Effect of mutual inductance coupling on superconducting flux qubit decoherence
Institute of Scientific and Technical Information of China (English)
Yanyan Jiang; Hualan Xu; Yinghua Ji
2009-01-01
In the Born-Markov approximation and two-level approximation, and using the Bloch-Redfield equation, the decoherence property of superconducting quantum circuit with a flux qubit is investigated. The influence on decoherence of the mutual inductance coupling between the circuit components is complicated. The mutual inductance coupling between different loops will decrease the decoherence time. However, the mutual inductance coupling of the same loop, in a certain interval, will increase the decoherence time. Therefore, we can control the decoherence time by changing the mutual inductance parameters such as the strength and direction of coupling.
International Nuclear Information System (INIS)
We have studied the single proton breakup from weakly bound exotic nuclei due to several reaction mechanisms separately and their total and the interference effects, in order to clarify quantitatively which mechanism would dominate the measured observables. We have considered: first, the recoil effect of the core-target Coulomb potential which we distinguish from the direct proton-target Coulomb potential, and secondly the nuclear breakup, which consists of stripping and diffraction. Thus, we have calculated the absolute values of breakup cross sections and parallel momentum distributions (LMD) for 8B and 17F projectiles on a light and a heavy target in a range of intermediate incident energies (40 A-80 A MeV) for each reaction mechanism. Furthermore the interference among the two Coulomb effects and nuclear diffraction has been studied in detail. The calculation of the direct and recoil Coulomb effects separately and of their interference is the new and most relevant aspect of this work. (authors)
Development and validation of models for bubble coalescence and breakup
International Nuclear Information System (INIS)
A generalized model for bubble coalescence and breakup has been developed, which is based on a comprehensive survey of existing theories and models. One important feature of the model is that all important mechanisms leading to bubble coalescence and breakup in a turbulent gas-liquid flow are considered. The new model is tested extensively in a 1D Test Solver and a 3D CFD code ANSYS CFX for the case of vertical gas-liquid pipe flow under adiabatic conditions, respectively. Two kinds of extensions of the standard multi-fluid model, i.e. the discrete population model and the inhomogeneous MUSIG (multiple-size group) model, are available in the two solvers, respectively. These extensions with suitable closure models such as those for coalescence and breakup are able to predict the evolution of bubble size distribution in dispersed flows and to overcome the mono-dispersed flow limitation of the standard multi-fluid model. For the validation of the model the high quality database of the TOPFLOW L12 experiments for air-water flow in a vertical pipe was employed. A wide range of test points, which cover the bubbly flow, turbulent-churn flow as well as the transition regime, is involved in the simulations. The comparison between the simulated results such as bubble size distribution, gas velocity and volume fraction and the measured ones indicates a generally good agreement for all selected test points. As the superficial gas velocity increases, bubble size distribution evolves via coalescence dominant regimes first, then breakup-dominant regimes and finally turns into a bimodal distribution. The tendency of the evolution is well reproduced by the model. However, the tendency is almost always overestimated, i.e. too much coalescence in the coalescence dominant case while too much breakup in breakup dominant ones. The reason of this problem is discussed by studying the contribution of each coalescence and breakup mechanism at different test points. The redistribution of the
Out-of-Equilibrium Chiral Magnetic Effect at Strong Coupling
Lin, Shu
2013-01-01
We study the charge transports originating from triangle anomaly in out-of-equilibrium conditions in the framework of AdS/CFT correspondence at strong coupling, to gain useful insights on possible charge separation effects that may happen in the very early stages of heavy-ion collisions. We first construct a gravity background of a homogeneous mass shell with a finite (axial) charge density gravitationally collapsing to a charged blackhole, which serves as a dual model for out-of-equilibrium charged plasma undergoing thermalization. We find that a finite charge density in the plasma slows down the thermalization. We then study the out-of-equilibrium properties of Chiral Magnetic Effect and Chiral Magnetic Wave in this background. As the medium thermalizes, the magnitude of chiral magnetic conductivity and the response time delay grow. We find a dynamical peak in the spectral function of retarded current correlator, which we identify as an out-of-equilibrium chiral magnetic wave. The group velocity of the out-...
International Nuclear Information System (INIS)
Nuclear break-up has been studied both from an experimental and a theoretical point of view and has shown to be a powerful tool to probe nucleon correlations in nuclei. A theory beyond mean-field, called TDDM, (Time Dependant Density Matrix) taking into account two-body correlations has been developed. The dynamical evolution of a correlated nuclei can be described and especially nuclear break-up. This study shows that the distributions of relative angle between the two neutrons strongly differ when varying initial correlations: two nucleons close together in the nuclei will lead to small relative angle after emission whereas two nucleons far from each other gives large relative angles. From an experimental point of view, correlations between the two neutrons in the halo of the Borromean nucleus He6 have been investigated. Its ground state is predicted to have two dominant configurations: the di-neutron configuration where the two neutrons are very close to each other and the cigar configuration, where the two neutrons are on opposite side with respect to the core. Nuclear break-up of He6 on a lead target has been studied at GANIL with a SPIRAL beam. The alpha particles coming out of the break-up where detected by a stripped Silicon detector coupled to a Silicon-Lithium detector and the neutrons by EDEN and the Neutron Wall, in order to get a large angular coverage. Angular correlation functions extracted from data show both strong correlation at small relative angles and at large relative angle corresponding respectively to the contribution of the di-neutron configuration and of the cigar like configuration. So He6 ground state seems to be a superposition of these two configurations. (author)
Joint venture breakup and the exploration-exploitation trade-off
LONG, Ngo van; Soubeyran, Antoine; Soubeyran, Raphael
2009-01-01
This paper explores the effect of a potential joint-venture breakup on the level of technology transfer in a set-up with exploration-exploitation trade-offs in the presence of time compression costs. We consider a joint-venture relationship between a technologically advanced multinational firm and a local firm operating in a developing economy where the ability to enforce contracts is weak, and the local firm can quit without penalties. The multinational firm has to consider the advantages an...
The study on the relationship between breakup modes and gas-liquid interfaces
Institute of Scientific and Technical Information of China (English)
DU Qing; LIU Ning; YIN Jun
2008-01-01
Based on the linear instability analysis, the study on the relationship between breakup modes and gas-liquid interfaces of a viscous annular liquid jet moving in two swirling gas streams has been car-ried out. From the numerical results of the dispersion equation, the relevancy of the breakup mode between an annular liquid jet and two liquid jets of limiting cases, namely the cylindrical liquid jet and hollow gas jet, as well as the effects of injecting factors on the instability of an annular liquid jet, is studied in detail. Considering the effects of inner and outer interface radii on the instability of the jet, it is proved that the para-sinuous mode mainly relates to the inner interface, whereas the para-varicose mode mainly relates to the outer interface. The results also indicate that all the forces produced by liquid jet have similar impacts on either the instability of para-sinuous mode or para-varicose mode due to the fact that they can affect both inner and outer gas-liquid interfaces. On the other hand, all the forces exerting only on the inner interface have more powerful effects on the instability of para-sinuous mode, and all the forces exerting only on the outer interface have more powerful effects on the insta-bility of para-varicose mode. That is to say, the effects of forces are weakened greatly when penetrating the liquid jet.
International Nuclear Information System (INIS)
In the ITER ion cyclotron system reference design, plasma loading is modelled by a 'transmission line' estimate of the diagonal term Zii of the coupling impedance matrix. The basic element of the ITER array, called ITER-like structure (ILS) is itself a poloidal array of 2 short-circuited current straps, each in series with a tuning capacitive reactance, and connected in parallel to the output of a RF power source, via a step-up impedance transformer. In this paper the effects of plasma coupling and other asymmetries are analysed for a generic ILS. It has been shown that any reasonable level of coupling and other electrical asymmetries do not affect load resilience in array of ILS, provided that conjugate symmetry between half sections currents is maintained in each array element by a suitable control system
Breakup of small aggregates driven by turbulent hydrodynamic stress
Babler, Matthaus U; Lanotte, Alessandra S
2012-01-01
Breakup of small solid aggregates in homogeneous and isotropic turbulence is studied theoretically and by using Direct Numerical Simulations at high Reynolds number, Re_{\\lambda} \\simeq 400. We show that turbulent fluctuations of the hydrodynamic stress along the aggregate trajectory play a key role in determining the aggregate mass distribution function. Differences between turbulent and laminar flows are discussed. A novel definition of the fragmentation rate is proposed in terms of the typical frequency at which the hydrodynamic stress becomes sufficiently high to cause breakup along each Lagrangian path. We also define an Eulerian proxy of the real fragmentation rate, based on the joint statistics of the stress and its time derivative, which should be easier to measure in any experimental set-up. Both our Eulerian and Lagrangian formulations define a clear procedure for the computation of the mass distribution function due to fragmentation. Contrary, previous estimates based only on single point statistic...
Numerical modeling of dimethyl ether (DME) bubble growth and breakup
Institute of Scientific and Technical Information of China (English)
ZHANG Peng; ZHANG YuSheng
2009-01-01
A numerical program is written to simulate the process of vapor bubble growth with spherical symmetry from the thermodynamic critical radius in an initially uniformly superheated liquid. The program is validated by the experimental data of superheated water. The calculated results agree with those of experiments well. The program takes into account the variations of properties with temperature precisely to simulate the DME bubble growth under flash boiling conditions. Considering the influences of pressure, surface tension and viscous stress, the linear stability analysis method is adopted to deduce the dispersion equation to represent the disturbance development during the bubble growth, and a new criterion for bubble breakup is established. The results show the bubble becomes more unstable with the increase of bubble Weber number and void fraction, and that with the increase of bubble growth rate or the decrease of initial radius ration of droplet to bubble, the breakup time of bubble becomes shorter.
Improvement of Jet Breakup Model in Fuel Coolant Interactions
Energy Technology Data Exchange (ETDEWEB)
Bang, Kwang Hyun; Kim, Kyung Kyu; Nam, Yang Ho [Korea Maritime Univ., Jinhae (Korea, Republic of)
2007-02-15
The objective of this work is to improve TRACER-II code in conjunction with the OECD SERENA project for validation of vapor explosion analysis codes. FCI breakup model is to be improved by building four-fluid multiphase flow model and existing models and experimental data are examined for the validation of the model. Four-fluid multiphase flow model has been built in TRACER-II code and jet breakup model has been included. Kelvin-Helmholtz instability is modelled for the jet side and boundary layer stripping is modelled for the jet leading edge. This work can contributes to the reduction of uncertainty in the FCI models for reactor safety analysis.
Microscopic Description of Diffractive Deuteron Breakup by He-3 Nuclei
Kovalchuk, Valery
2016-01-01
A microscopic formalism for describing observed cross sections for deuteron breakup by three-nucleon nuclei was developed on the basis of the diffraction nuclear model. A general formula that describes the amplitude for the reaction d+3He->3He+p+n and which involves only one adjustable parameter was obtained by using expansions of the integrands involved in terms of a Gaussian basis. This formula was used to analyze experimental data on the exclusive cross sections for deuteron breakup by He-3 nuclei at the projectile energy of 89.4 MeV. The importance of employing, in calculations, a deuteron wave function that has a correct asymptotic behavior at large nucleon-nucleon distances was demonstrated.
Magnetocaloric effect at the exchange–inversion with magnetoelastic coupling
Energy Technology Data Exchange (ETDEWEB)
Piazzi, Marco, E-mail: m.piazzi@inrim.it; Basso, Vittorio
2015-09-15
We develop a thermodynamic model to describe antiferro- (AFM) to ferromagnetic (FM) phase transitions through magnetoelastic coupling in the framework of Kittel's exchange–inversion mechanism. By including both magnetic and structural contributions to the free energy, we derive the conditions to have a direct AFM–FM transition. These are represented either by the presence of a non-zero intra-sublattice coupling constant or by a sufficiently high value of the magnetoelastic coupling parameter. In the paper we establish these conditions by analytical means and we discuss the physical meaning of the model in relation to possible applications to magnetocaloric materials with AFM–FM transitions.
Magnetocaloric effect at the exchange-inversion with magnetoelastic coupling
Piazzi, Marco; Basso, Vittorio
2015-09-01
We develop a thermodynamic model to describe antiferro- (AFM) to ferromagnetic (FM) phase transitions through magnetoelastic coupling in the framework of Kittel's exchange-inversion mechanism. By including both magnetic and structural contributions to the free energy, we derive the conditions to have a direct AFM-FM transition. These are represented either by the presence of a non-zero intra-sublattice coupling constant or by a sufficiently high value of the magnetoelastic coupling parameter. In the paper we establish these conditions by analytical means and we discuss the physical meaning of the model in relation to possible applications to magnetocaloric materials with AFM-FM transitions.
Study on breakup behavior of molten material JET in coolant
International Nuclear Information System (INIS)
It is important to estimate the jet breakup behavior of the molten core material jet in coolant during a core distractive accident (CDA) of a fast breeder reactor (FBR). In the present study, the molten jet of U-alloy 78 simulating the core material is injected into the water simulating the coolant. The visual data of the molten jet breakup behavior is observed by using the high-speed video camera. The front velocity of the molten jet is estimated by using the image processing technique from the visual data. It shows that the front velocity of the molten jet can be divided into three regions in time. In first region, the front velocity of the molten jet increases. In second region, the front velocity of the molten jet suddenly decreases. In third region, the front velocity of the molten jet keeps at low and steady. In first region, the column diameter of the molten jet decreases with the passage of time. At the location between first region and second region, the column of the molten jet breaks up and disappears. It is experimentally observed that the molten material column in the molten material jet from breaks up and disappears as the border time between the first and the second regions. In the present study, the jet breakup length is defined as the distance from the water surface to the location between the first and the second regions, since the main body of the molten material jet column is fragmented at the time and location. From the present experimental results, it is clarified that the jet breakup behavior depends on the injection nozzle diameter but independs on the penetration velocity of the molten material jet. The present experimental results are different from qualitative tendency of the formula by Saito at al. but are qualitatively similar by Epstein et al.. (author)
Break-up of a non-Newtonian jet injected downwards in a Newtonian liquid
Indian Academy of Sciences (India)
Absar M Lakdawala; Rochish Thaokar; Atul Sharma
2015-05-01
The present work on downward injection of non-Newtonian jet is an extension of our recent work (Lakdawala et al, Int. J. Multiphase Flow. 59: 206–220, 2014) on upward injection of Newtonian jet. The non-Newtonian rheology of the jet is described by a Carreau type generalized Newtonian fluid (GNF) model, which is a phenomenological constitutive equation that accounts for both rate-thinning and rate-thickening. Level set method based numerical study is done for Newtonian as well as various types of shear thinning and thickening jet fluid. Effect of average injection velocity ($V_{av,i}$) is studied at a constant Reynolds number Re = 14.15, Weber number W e = 1, Froude number F r = 0.25, density ratio $\\chi$ = 0.001 and viscosity ratio $\\eta$ = 0.01. CFD analysis of the temporal variation of interface and jet length ($L_{j}$) is done to propose different types of jet breakup regimes. At smaller, intermediate and larger values of $V_{av,i}$, the regimes found are periodic uniform drop (P-UD), quasi-periodic non-uniform drop (QP-NUD) and no breakup (NB) regimes for a shear thinning jet; and periodic along with Satellite Drop (P+S), jetting (J) and no breakup (NB) regimes for a shear thickening jet, respectively. This is presented as a drop-formation regime map. Shear thickening (thinning) is shown to produce long (short) jet length. Diameter of the primary drop increases and its frequency of release decreases, due to increase in stability of the jet for shear thickening as compared to thinning fluid.
Neutron-neutron quasifree scattering in nd breakup at 10 MeV
Malone, R. C.; Crowe, B.; Crowell, A. S.; Cumberbatch, L. C.; Esterline, J. H.; Fallin, B. A.; Friesen, F. Q. L.; Han, Z.; Howell, C. R.; Markoff, D.; Ticehurst, D.; Tornow, W.; Witała, H.
2016-03-01
The neutron-deuteron (nd) breakup reaction provides a rich environment for testing theoretical models of the neutron-neutron (nn) interaction. Current theoretical predictions based on rigorous ab-initio calculations agree well with most experimental data for this system, but there remain a few notable discrepancies. The cross section for nn quasifree (QFS) scattering is one such anomaly. Two recent experiments reported cross sections for this particular nd breakup configuration that exceed theoretical calculations by almost 20% at incident neutron energies of 26 and 25 MeV [1, 2]. The theoretical values can be brought into agreement with these results by increasing the strength of the 1S0 nn potential matrix element by roughly 10%. However, this modification of the nn effective range parameter and/or the 1S0 scattering length causes substantial charge-symmetry breaking in the nucleon-nucleon force and suggests the possibility of a weakly bound di-neutron state [3]. We are conducting new measurements of the cross section for nn QFS in nd breakup. The measurements are performed at incident neutron beam energies below 20 MeV. The neutron beam is produced via the 2H(d, n)3He reaction. The target is a deuterated plastic cylinder. Our measurements utilize time-of-flight techniques with a pulsed neutron beam and detection of the two emitted neutrons in coincidence. A description of our initial measurements at 10 MeV for a single scattering angle will be presented along with preliminary results. Also, plans for measurements at other energies with broad angular coverage will be discussed.
Solving the three-body Coulomb breakup problem using exterior complex scaling
Energy Technology Data Exchange (ETDEWEB)
McCurdy, C.W.; Baertschy, M.; Rescigno, T.N.
2004-05-17
Electron-impact ionization of the hydrogen atom is the prototypical three-body Coulomb breakup problem in quantum mechanics. The combination of subtle correlation effects and the difficult boundary conditions required to describe two electrons in the continuum have made this one of the outstanding challenges of atomic physics. A complete solution of this problem in the form of a ''reduction to computation'' of all aspects of the physics is given by the application of exterior complex scaling, a modern variant of the mathematical tool of analytic continuation of the electronic coordinates into the complex plane that was used historically to establish the formal analytic properties of the scattering matrix. This review first discusses the essential difficulties of the three-body Coulomb breakup problem in quantum mechanics. It then describes the formal basis of exterior complex scaling of electronic coordinates as well as the details of its numerical implementation using a variety of methods including finite difference, finite elements, discrete variable representations, and B-splines. Given these numerical implementations of exterior complex scaling, the scattering wave function can be generated with arbitrary accuracy on any finite volume in the space of electronic coordinates, but there remains the fundamental problem of extracting the breakup amplitudes from it. Methods are described for evaluating these amplitudes. The question of the volume-dependent overall phase that appears in the formal theory of ionization is resolved. A summary is presented of accurate results that have been obtained for the case of electron-impact ionization of hydrogen as well as a discussion of applications to the double photoionization of helium.
Investigation of correlations in the breakup of He8
International Nuclear Information System (INIS)
Correlations in light neutron-rich nuclei are of considerable importance in understanding their structure. In this context the breakup of He8 into He6 + 2n has been investigated at 15 MeV/nucleon. The measurements were undertaken using a setup composed of two detector arrays: CHARISSA to detect the charged fragments and DEMON to detect the neutrons. The interpretation of the results was facilitated using a Monte Carlo simulation which was developed to take into account the correlations, the reaction and the experimental setup. Two techniques were used to study the correlations in the breakup of He8. The first, intensity interferometry, provides, via the construction of the neutron-neutron correlation function, for a first estimate of the source size and thus the average separation between the neutrons. The second, using Dalitz plots, allows both the neutron-neutron and core-neutron correlations to be probed. Here, sequential decay via the ground state resonance of He7 and has been found to dominate the dissociation of He8. The spatial and temporal characteristics of the breakup of He8 have thus been deduced and a root-mean-square separation between the two valence neutrons in the continuum states was estimated to be (7.3 ± 0.6) fm with a time delay between their emission of (1000 ± 300) fm/c. (author)
Breakup length of harmonically stimulated capillary jets - theory and experiments
Garcia Garcia, Francisco Javier; Gonzalez Garcia, Heliodoro; Castrejon-Pita, Jose Rafael; Castrejon-Pita, Alfonso Arturo
2014-11-01
A stream of liquid breaks up into several drops by the action of surface tension. Capillary breakup forms the basis of some modern digital technologies, especially inkjet printing (including 3D manufacturing). Therefore, the control and prediction of the breakup length of harmonically modulated capillary jets is of great importance, in particular in Continuous InkJet systems (CIJ). However, a theoretical model that rigorously takes into account the physical characteristics of the system, and that properly describes this phenomenon did not exist until now. In this work we present a simple transfer function, derived from first principles, that accurately predicts the experimentally obtained breakup lengths of pressure-modulated capillary jets. No fitting parameters are necessary. A detailed description of the theoretical model and experimental setup will be presented. Spanish government (FIS2011-25161), Junta de Andalucia (P09-FQM-4584 and P11-FQM-7919), EPSRC-UK (EP/H018913/1), Royal Society and John Fell Fund (OUP).
Effect of the isovector coupling channel on the macroscopic part of the nuclear binding energy
Indian Academy of Sciences (India)
S Haddad
2013-05-01
The effect of isovector coupling channel on the macroscopic part of the nuclear binding energy is studied using the relativistic density-dependent Thomas–Fermi approach. The dependency of this effect on the number of neutrons and protons is also studied. The isovector coupling channel leads to increased nuclear binding energy, and this effect increases with the increasing neutron number in the nucleus.
Salama, Ahmed; Ling, Lisa
2005-01-01
Vehicle breakup analysis has been performed for missions that may carry nuclear fuel for heating or power purposes to assess nuclear safety in case of launch failure leading to atmospheric reentry. Also, failure scenarios exist which could lead to breakup during Entry / Descent / Landing (EDL) at Mars due to off-nominal entries, with implications for planetary protection requirements. Since the Mars Science Laboratory (MSL) spacecraft may include a Multi-Mission Radioisotope Thermoelectric Generator (MMRTG), an analysis of breakup in case of launch failure is required. Also, breakup during Mars EDL due to off-nominal entries could release the RTG heat source that has implications for planetary protection requirements. This paper presents a methodology of MSL breakup analysis for launch failure with application to Mars off-nominal entry.
Flow visualization of Taylor-mode breakup of a viscous liquid jet
Tsai, Shirley C.; Luu, Patrick; Tam, Patrick; Roski, Gerald; Tsai, Chen S.
1999-06-01
We recently reported a new spray technique called ultrasound-modulated two-fluid (UMTF) atomization and the pertinent "resonant liquid capillary wave (RLCW) theory" based on linear models of Taylor-mode breakup of capillary waves. In this article, flow visualizations of liquid jets near the nozzle tip are presented to verify the central assumption of the RLCW theory that the resonant liquid capillary wave in UMTF atomization is initiated by the ultrasound at the nozzle tip. Specifically, a bright band beneath the nozzle tip was seen in ultrasonic and UMTF atomization separately, but not in two-fluid atomization. The bright band can be attributed to scattering of laser light sheet by the capillary waves generated by the ultrasound on the intact liquid jet. As the capillary wave travels downstream in the direction of airflow, it is amplified by the air blowing around it and eventually collapsed into drops. Therefore, the jet breakup time can be determined by dividing the measured band length with the capillary wave velocity. The breakup times thus determined for water and glycerol/water jets are twice the values predicted by the modified Taylor's model with a sheltering parameter, and are one order of magnitude shorter than those in conventional two-fluid atomization. Furthermore, the images of the spray in the proximity of the nozzle tip obtained by 30 ns laser pulses are consistent with the drop sizes obtained 2.3-6 cm downstream from the nozzle tip by 13 s time average of continuous laser light. Also reported in this article is the good agreement between the measured viscosity effects on the drop-size and size distribution in UMTF atomization and those on the relative amplitude growth rates of capillary waves at different wavelengths predicted by Taylor's model as a result of its inclusion of higher order terms other than the first in viscosity. These new findings have led to the conclusion that UMTF atomization occurs via Taylor-mode breakup of capillary waves
An Attempt to Observe Debris from the Breakup of a Titan 3C-4 Transtage
Barker, E. S.; Matney, M. J.; Yanagisawa, T.; Liou, J.-C.; Abercromby, K. J.; Rodriquez, H. M.; Horstman, M. F.; Seitzer, P.
2007-01-01
In February 2007 dedicated observations were made of the orbital space predicted to contain debris from the breakup of the Titan 3C-4 transtage back on February 21, 1992. These observations were carried out on the Michigan Orbital DEbris Survey Telescope (MODEST) in Chile with its 1.3deg field of view. The search region or orbital space (inclination and right ascension of the ascending node (RAAN) was predicted using NASA#s LEGEND (LEO-to-GEO Environment Debris) code to generate a Titan debris cloud. Breakup fragments are created based on the NASA Standard Breakup Model (including fragment size, area-to-mass (A/M), and delta-V distributions). Once fragments are created, they are propagated forward in time with a subroutine GEOPROP. Perturbations included in GEOPROP are those due to solar/lunar gravity, radiation pressure, and major geopotential terms. Barker, et. al, (AMOS Conference Proceedings, 2006, pp. 596-604) used similar LEGEND predictions to correlate survey observations made by MODEST (February 2002) and found several possible night-to-night correlations in the limited survey dataset. One conc lusion of the survey search was to dedicate a MODEST run to observing a GEO region predicted to contain debris fragments and actual Titan debris objects (SSN 25000, 25001 and 30000). Such a dedicated run was undertaken with MODEST between February 17 and 23, 2007 (UT dates). MODEST#s limiting magnitude of 18.0 (S\\N approx.10) corresponds to a size of 22cm assuming a diffuse Lambertian albedo of 0.2. However, based on observed break-up data, we expect most debris fragments to be smaller than 22cm which implies a need to increase the effective sensitivity of MODEST for smaller objects. MODEST#s limiting size can be lowered by increasing the exposure time (20 instead of 5 seconds) and applying special image processing. The special processing combines individual CCD images to detect faint objects that are invisible on a single CCD image. Sub-images are cropped from six
Effective gravitational couplings for cosmological perturbations in generalized Proca theories
De Felice, Antonio; Heisenberg, Lavinia; Kase, Ryotaro; Mukohyama, Shinji; Tsujikawa, Shinji; Zhang, Ying-li
2016-08-01
We consider the finite interactions of the generalized Proca theory including the sixth-order Lagrangian and derive the full linear perturbation equations of motion on the flat Friedmann-Lemaître-Robertson-Walker background in the presence of a matter perfect fluid. By construction, the propagating degrees of freedom (besides the matter perfect fluid) are two transverse vector perturbations, one longitudinal scalar, and two tensor polarizations. The Lagrangians associated with intrinsic vector modes neither affect the background equations of motion nor the second-order action of tensor perturbations, but they do give rise to nontrivial modifications to the no-ghost condition of vector perturbations and to the propagation speeds of vector and scalar perturbations. We derive the effective gravitational coupling Geff with matter density perturbations under a quasistatic approximation on scales deep inside the sound horizon. We find that the existence of intrinsic vector modes allows a possibility for reducing Geff. In fact, within the parameter space, Geff can be even smaller than the Newton gravitational constant G at the late cosmological epoch, with a peculiar phantom dark energy equation of state (without ghosts). The modifications to the slip parameter η and the evolution of the growth rate f σ8 are discussed as well. Thus, dark energy models in the framework of generalized Proca theories can be observationally distinguished from the Λ CDM model according to both cosmic growth and expansion history. Furthermore, we study the evolution of vector perturbations and show that outside the vector sound horizon the perturbations are nearly frozen and start to decay with oscillations after the horizon entry.
The continuum discretized coupled-channels method and its applications
Yahiro, Masanobu; Matsumoto, Takuma; Minomo, Kosho
2012-01-01
This is a review on recent developments of the continuum discretized coupled-channels method (CDCC) and its applications to nuclear physics, cosmology and astrophysics, and nuclear engineering. The theoretical foundation of CDCC is shown, and a microscopic reaction theory for nucleus-nucleus scattering is constructed as an underlying theory of CDCC. CDCC is then extended to treat Coulomb breakup and four-body breakup. We also propose a new theory that makes CDCC applicable to inclusive reactions
Specific Heat of Hollow Nanosphere Coupled to Substrate: Quantum Size Effects
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
With the help of the elastic wave theory, in the perturbed approximation the density-of-states for vibrational modes and the specific heat axe studied for different hollow Si nanospheres, coupled with a semi-infinite substrate. We find that the modes of such coupled hollow spheres are significantly broadened and shifted toward low frequencies. The specific heat of the coupled hollow nanosphere is bigger than an isolated one due to the coupling interaction and quantum size effects. The predicted coupling and size enhancements on specific heat are probed in thermal experiments.
Psychological distress of marital and cohabitation breakups.
Tavares, Lara Patrício; Aassve, Arnstein
2013-11-01
Using data from a large survey, the British Household Panel Survey (BHPS), this paper explores the extent to which marital and cohabiting unions differ with respect to the short-term effects of union dissolution on mental health. We compare married individuals who divorced or separated with cohabitors whose first union ended and test the hypothesis that married individuals experience larger negative effects. Results show that initial differences are not statistically significant once the presence of children is controlled for, suggesting that the presence of children is a particularly significant source of increased psychological distress in union dissolutions. However, parenthood does not explain serious psychological distress, which appears to be associated with enduring traits (the personality trait neuroticism).
Psychological distress of marital and cohabitation breakups.
Tavares, Lara Patrício; Aassve, Arnstein
2013-11-01
Using data from a large survey, the British Household Panel Survey (BHPS), this paper explores the extent to which marital and cohabiting unions differ with respect to the short-term effects of union dissolution on mental health. We compare married individuals who divorced or separated with cohabitors whose first union ended and test the hypothesis that married individuals experience larger negative effects. Results show that initial differences are not statistically significant once the presence of children is controlled for, suggesting that the presence of children is a particularly significant source of increased psychological distress in union dissolutions. However, parenthood does not explain serious psychological distress, which appears to be associated with enduring traits (the personality trait neuroticism). PMID:24090854
Classical simulations of heavy-ion fusion reactions and weakly-bound projectile breakup reactions
Indian Academy of Sciences (India)
S S Godre
2014-05-01
Heavy-ion collision simulations in various classical models are discussed. Heavy-ion reactions with spherical and deformed nuclei are simulated in a classical rigid-body dynamics (CRBD) model which takes into account the reorientation of the deformed projectile. It is found that the barrier parameters depend not only on the initial orientations of the deformed nucleus, but also on the collision energy and the moment of inertia of the deformed nucleus. Maximum reorientation effect occurs at near- and below-barrier energies for light deformed nuclei. Calculated fusion crosssections for 24Mg + 208Pb reaction are compared with a static-barrier-penetration model (SBPM) calculation to see the effect of reorientation. Heavy-ion reactions are also simulated in a 3-stage classical molecular dynamics (3S-CMD) model in which the rigid-body constraints are relaxed when the two nuclei are close to the barrier thus, taking into account all the rotational and vibrational degrees of freedom in the same calculation. This model is extended to simulate heavy-ion reactions such as 6Li + 209Bi involving the weakly-bound projectile considered as a weakly-bound cluster of deuteron and 4He nuclei, thus, simulating a 3-body system in 3S-CMD model. All the essential features of breakup reactions, such as complete fusion, incomplete fusion, no-capture breakup and scattering are demonstrated.
Assessment of breakup severity on operational satellites
Letizia, Francesca; Colombo, Camilla; Lewis, Hugh G.; Krag, Holger
2016-10-01
In the past years, several methods have been proposed to rank spacecraft and space debris objects depending on their effect on the space environment. The interest in this kind of indices is primarily motivated by the need of prioritising potential candidates of active debris removal missions and to decide on the required reliability for disposal actions during the design phase. The index proposed in this work measures the effect of the catastrophic fragmentation of the analysed spacecraft in terms of the resulting collision probability for operational spacecraft. The propagation of the debris cloud generated by the fragmentation and the estimation of the collision probability are obtained by applying an analytical approach based on the study of the density of the fragment cloud. The dependence of the proposed severity index on the mass of the spacecraft and on its semi-major axis and inclination is investigated. The index was computed for the objects in the DISCOS database and its results were compared to other formulations proposed in literature. A discussion on the results and on the comparison is presented.
Manipulating effective spin orbit coupling based on proximity effect in magnetic bilayers
Energy Technology Data Exchange (ETDEWEB)
Zhang, Y. Q.; Sun, N. Y.; Che, W. R.; Zhang, J. W.; Shan, R., E-mail: shan.rong@hotmail.com [School of Physics Science and Engineering, Tongji University, Shanghai 200092 (China); Li, X. L. [Shanghai Synchrotron Radiation Facility (SSRF), Shanghai 201204 (China); Zhu, Z. G., E-mail: zgzhu@ucas.ac.cn; Su, G., E-mail: gsu@ucas.ac.cn [School of Electronic, Electrical and Communication Engineering, University of Chinese Academy of Sciences, Beijing 100049 (China); Theoretical Condensed Matter Physics and Computational Materials Physics Laboratory, College of Physical Sciences, University of Chinese Academy of Sciences, Beijing 100049 (China)
2015-08-24
A proximity effect of spin orbit coupling (SOC) is proposed in nonmagnetic metal/ferromagnet (NM/FM) bilayers by extending the Crépieux-Bruno (CB) theory. We demonstrate that over 1000% enhancement of the SOC strength can be realized based on this effect (Pt/FM bilayers) and it brings greatly enhanced anomalous Hall effect and anomalous Nernst effect. This work could help maximize the performance of magnetic transport property for the spintronics device using NM/FM as the key structure.
Comparison of the cable coupling effects under two kinds of HEMP environment
Sun Bei Yun; Xie Yan Zhao
2002-01-01
There are various kinds of HEMP environment definitions. The coupling effects of electronic system are more different under different HEMP environment. The responds of cable of different length are investigated under 1976 HEMP and 1996 HEMP environment. The results indicate that the cable coupling effects under 1976 HEMP environment are more serious than those under 1996 HEMP environment
Breakup mechanisms for 7Li + 197Au, 204Pb systems at sub-barrier energies
Directory of Open Access Journals (Sweden)
Luong D.H.
2013-12-01
Full Text Available Coincidence measurements of breakup fragments were carried out for the 7Li + 197Au and 204Pb systems at sub-barrier energies. The mechanisms triggering breakup, and time-scales of each process, were identified through the reaction Q-values and the relative energy of the breakup fragments. Binary breakup of 7Li were found to be predominantly triggered by nucleon transfer, with p-pickup leading to 8Be → α + α decay being the preferred breakup mode. From the time-scales of each process, the coincidence yields were separated into prompt and delayed components, allowing the identification of breakup process important in the suppression of complete fusion of 7Li at above-barrier energies.
Higgs-Z-photon coupling from effect of composite resonances
International Nuclear Information System (INIS)
We explore the Higgs-Z-photon coupling in the Minimal Composite Higgs Model with vector and axial resonances. The electroweak precision measurement, i.e. S and T, is estimated for this model. We calculate the signal strength for Higgs decay into Z-photon and notable enhancement is found in certain EWPT allowed parameter region
FRUSTRATION EFFECT ON SYNCHRONIZATION AND CHAOS IN COUPLED OSCILLATORS
Institute of Scientific and Technical Information of China (English)
ZHENG ZHI-GANG
2001-01-01
Synchronization dynamics in an array of coupled periodic oscillators with quenched natural frequencies are discussed in the presence of homogeneous phase shifts (frustrations). Frustration-induced desynchronization and chaos are found. The torus-doubling route to chaos, toroidal chaos and torus crisis are investigated.
MAFIA analysis of the effects of coupling slots in linacs
Adams, F. P.; Ungrin, J.; de Jong, M. S.
1991-05-01
We have used the MAFIA codes to analyze on-axis slot-coupled {π}/{2}- mode standing-wave linac structures. Quadrupolar fields in the structure are found to produce an elliptical accelerated beam. A modification to the design, yielding reduced beam ellipticity, is proposed.
Complete kinematical study of the 3α breakup of the 16.11 MeV state in 12C
Laursen, K. L.; Fynbo, H. O. U.; Kirsebom, O. S.; Madsbøll, K. S.; Riisager, K.
2016-09-01
The reaction 11 B + p has been used to populate the (J^{π},T) = (2+,1) state at an excitation energy of 16.11 MeV in 12C, and the breakup of the state into three α-particles has been studied in complete kinematics. A two-step breakup model which includes interference effects is found to provide the most accurate description of the experimental data. The branching ratio to the ground state of 8Be is determined to be 5.1(5)% in agreement with previous findings, but more precise by a factor of two, while the decay to the first excited state in 8Be is found to be dominated by d-wave emission.
Complete kinematical study of the 3$\\alpha$ breakup of the 16.11 MeV state in $^{12}$C
Laursen, K L; Kirsebom, O S; Madsbøl, K O; Riisager, K
2016-01-01
The reaction $^{11}B+p$ has been used to populate the $(J^{\\pi},T)=(2^+,1)$ state at an excitation energy of 16.11 MeV in $^{12}$C, and the breakup of the state into three $\\alpha$ particles has been studied in complete kinematics. A two-step breakup model which includes interference effects is found to provide the most accurate description of the experimental data. The branching ratio to the ground state of $^8$Be is determined to be 5.1(5)% in agreement with previous findings, but more precise by a factor of two, while the decay to the first-excited state in $^8$Be is found to be dominated by $d$-wave emission.
Institute of Scientific and Technical Information of China (English)
无
2007-01-01
An effective method is introduced to compensate the effects of mutual coupling for the Estimation of Signal Parameter via Rotational Invariance Techniques (ESPRIT) direction finding algorithm in application of signal snapshot array processing. Changing the covariance matrix into a Teoplitz matrix can achieve high resolution in the Direction Of Arrive (DOA) estimation. How the mutual coupling affects the array antennas has been discussed and a new definition of mutual impedance has been used to characterize the mutual coupling effects between the array elements. Based on the new mutual impedance matrix, a practical method is presented to eliminate the effects of mutual coupling for ESPRIT in the single snapshot data processing. The simulation results show that,this new method not only properly reduces the effects of mutual coupling, but also maintains its steady performance even for weak signals.
MODEL OF SEA ICE BREAKUP ON SHALLOW BEACH DUE TO TIDAL FLUCTUATION
Institute of Scientific and Technical Information of China (English)
无
2000-01-01
There are many factors that may lead to the breakup of shore fast ice, such as wind, wave, tide and so on.This paper mainly analyzed the ice breakup on the shallow beach due to tidal fluctuation.The theoretical model was set up and the fitting range was given.The calculated result shows that the slope angle α, the ice thickness h, and the ice length l are key factors in determining the ice breakup length lp.
Medium modifications of the nucleon--deuteron break--up cross section in the Faddeev approach
M. Beyer; G. Röpke; Sedrakian, A.
1996-01-01
The three--nucleon scattering problem in a nuclear medium is considered within the Faddeev technique. In particular the deuteron break--up cross section that governs the formation and the break--up reactions of deuterons (NNN Nd) in a nuclear environment is calculated at finite temperatures and densities. A significant enhancement of the in--medium break--up cross section with increasing density has been found.
Effects of quantum coupling on the performance of metal-oxide-semiconductor field transistors
Indian Academy of Sciences (India)
Ling-Feng Mao
2009-02-01
Based on the analysis of the three-dimensional Schrödinger equation, the effects of quantum coupling between the transverse and the longitudinal components of channel electron motion on the performance of ballistic MOSFETs have been theoretically investigated by self-consistently solving the coupled Schrödinger–Poisson equations with the finite-difference method. The results show that the quantum coupling between the transverse and the longitudinal components of the electron motion can largely affect device performance. It suggests that the quantum coupling effect should be considered for the performance of a ballistic MOSFET due to the high injection velocity of the channel electron.
Effects of Different Time-Dependent Couplings on Two-Atom Entanglement
Institute of Scientific and Technical Information of China (English)
ZHOU Ling; GAO Wen-Bin; YANG Guo-Hui; SONG He-Shan
2007-01-01
The effects of different time-independent and time-dependent couplings on two-atom entanglement are studied. The results show that the effects depend on the initial state. For the initial state |ee0>, it is found that different time-independent couplings make the case without entanglement exhibit entanglement, and time-dependent couplings turn the irregular entanglement regions into regular one. Under the case of decay, for the initial state |eg0>, the different time-dependent couplings have disbenefit.
Extrinsic spin Hall effect from anisotropic Rashba spin-orbit coupling in graphene
Yang, H.-Y.; Huang, Chunli; Ochoa, H.; Cazalilla, M. A.
2016-02-01
We study the effect of anisotropy of the Rashba coupling on the extrinsic spin Hall effect due to spin-orbit active adatoms on graphene. In addition to the intrinsic spin-orbit coupling, a generalized anisotropic Rashba coupling arising from the breakdown of both mirror and hexagonal symmetries of pristine graphene is considered. We find that Rashba anisotropy can strongly modify the dependence of the spin Hall angle on carrier concentration. Our model provides a simple and general description of the skew scattering mechanism due to the spin-orbit coupling that is induced by proximity to large adatom clusters.
Cumulative beam break-up study of the spallation neutron source superconducting linac
Jeon, D; Krafft, G A; Yunn, B; Sundelin, R; Delayen, J; Kim, S; Doleans, M
2002-01-01
Beam instabilities due to High Order Modes (HOMs) are a concern to superconducting (SC) linacs such as the Spallation Neutron Source (SNS) linac. The effects of pulsed mode operation on transverse and longitudinal beam breakup instability are studied for H sup - beam in a consistent manner for the first time. Numerical simulation indicates that cumulative transverse beam breakup instabilities are not a concern in the SNS SC linac, primarily due to the heavy mass of H sup - beam and the HOM frequency spread resulting from manufacturing tolerances. As little as +-0.1 MHz HOM frequency spread stabilizes all the instabilities from both transverse HOMs, and also acts to stabilize the longitudinal HOMs. Such an assumed frequency spread of +-0.1 MHz HOM is small, and hence conservative compared with measured values of sigma=0.00109(f sub H sub O sub M -f sub 0)/f sub 0 obtained from Cornell and the Jefferson Lab Free Electron Laser cavities. However, a few cavities may hit resonance lines and generate a high heat lo...
The use of the nonlinear optical loop mirror for investigations of pulse breakup in optical fibers
Kuzin, Evgeny A.; Pottiez, Olivier; Ibarra-Escamilla, Baldemar
2011-03-01
Pulse breakup and the formation of a bunch of solitons are the principal processes at the initial stage of the supercontinuum generation using long pulses for pumping. Most investigations use the measurement of the output spectrum to characterize the development of the supercontinuum. The extraction of an individual soliton or a group of solitons with similar parameters from the bunch can reveal details that are usually hidden when only the output spectrum is measured. Earlier we have studied the NOLM including a twisted fiber and a quarter wave retarder (QWR) in the loop. Its operation is based on the nonlinear polarization rotation effect. We showed that this NOLM is stable to changes of environmental conditions, and allows simple and predictable changes of its characteristics. In previous works we demonstrated its application for mode-locked lasers, pedestal suppression, or retrieval of a pulse shape. In this work we demonstrate that the NOLM is a viable device for the investigation of pulse breakup process and soliton formation. The operation principle is based on the fact that the NOLM has a maximum transmission for the solitons with specific durations while solitons with shorter and longer durations are strongly rejected. The duration associated with high transmission depends on the NOLM length and can also be changed by amplification of the solitons before entering the NOLM. By an appropriate choice of the NOLM parameters and the amplification of the bunch of solitons, the extraction of the solitons with selected parameters is possible.
The break-up dynamics of liquid threads revealed by laser radiation pressure and optocapillarity
Petit, Julien; Robert de Saint Vincent, Matthieu; Rivière, David; Kellay, Hamid; Delville, Jean-Pierre
2014-09-01
We show how optocapillary stresses and optical radiation pressure effects in two-phase liquids open the way for investigating the difficult problem of liquid thread breakup at small scales when surfactants are present at the interface or when the roughness of the interface becomes significant. Using thermocapillary stresses driven by light to pinch a surfactant-laden microjet, we observe deviations from the expected visco-capillary law governed by a balance between viscosity and interfacial tension. We suggest that these deviations are due to time varying interfacial tension resulting from the surfactant depletion at the neck pinching location, and we experimentally confirm this mechanism. The second case is representative of the physics of nanojets. Considering a near critical liquid-liquid interface, where the roughness of the interfaces may be tuned, we use the radiation pressure of a laser wave to produce stable fluctuating liquid columns and study their breakup. We show how pinching crosses over from the visco-capillary to a fluctuation dominated regime and describe this new regime. These experiments exemplify how optofluidics can reveal new physics of fluids.
Bag-breakup control of surface drag in hurricanes
Troitskaya, Yuliya; Zilitinkevich, Sergej; Kandaurov, Alexander; Ermakova, Olga; Kozlov, Dmitry; Sergeev, Daniil
2016-04-01
Air-sea interaction at extreme winds is of special interest now in connection with the problem of the sea surface drag reduction at the wind speed exceeding 30-35 m/s. This phenomenon predicted by Emanuel (1995) and confirmed by a number of field (e.g., Powell, et al, 2003) and laboratory (Donelan et al, 2004) experiments still waits its physical explanation. Several papers attributed the drag reduction to spume droplets - spray turning off the crests of breaking waves (e.g., Kudryavtsev, Makin, 2011, Bao, et al, 2011). The fluxes associated with the spray are determined by the rate of droplet production at the surface quantified by the sea spray generation function (SSGF), defined as the number of spray particles of radius r produced from the unit area of water surface in unit time. However, the mechanism of spume droplets' formation is unknown and empirical estimates of SSGF varied over six orders of magnitude; therefore, the production rate of large sea spray droplets is not adequately described and there are significant uncertainties in estimations of exchange processes in hurricanes. Herewith, it is unknown what is air-sea interface and how water is fragmented to spray at hurricane wind. Using high-speed video, we observed mechanisms of production of spume droplets at strong winds by high-speed video filming, investigated statistics and compared their efficiency. Experiments showed, that the generation of the spume droplets near the wave crest is caused by the following events: bursting of submerged bubbles, generation and breakup of "projections" and "bag breakup". Statistical analysis of results of these experiments showed that the main mechanism of spray-generation is attributed to "bag-breakup mechanism", namely, inflating and consequent blowing of short-lived, sail-like pieces of the water-surface film. Using high-speed video, we show that at hurricane winds the main mechanism of spray production is attributed to "bag-breakup", namely, inflating and
Experimental study on breakup characteristics of molten jet falling in gas plenum and water pool
Energy Technology Data Exchange (ETDEWEB)
Akinaga, Makoto; Kurita, Tomohisa; Yokobori, Seiichi [Toshiba Corp., Kawasaki, Kanagawa (Japan)
2001-07-01
The breakup characteristics of liquid jet issuing to air plenum and flowing into liquid pool were experimentally clarified. The jet breakup behavior around air was classified varying liquid substance. The bismuth and stannum molten jet was found to maintain its original shape. Moreover, breakup behavior of this molten jet during falling into the water pool was visualized. From the lump sedimented to the bottom, break-up behavior was found to be affected by the water subcooling which determining the balance between boiling and solidifying. (author)
Experimental study on breakup characteristics of molten jet falling in gas plenum and water pool
International Nuclear Information System (INIS)
The breakup characteristics of liquid jet issuing to air plenum and flowing into liquid pool were experimentally clarified. The jet breakup behavior around air was classified varying liquid substance. The bismuth and stannum molten jet was found to maintain its original shape. Moreover, breakup behavior of this molten jet during falling into the water pool was visualized. From the lump sedimented to the bottom, break-up behavior was found to be affected by the water subcooling which determining the balance between boiling and solidifying. (author)
Application of Multiphase Particle Methods in Atomization and Breakup Regimes of Liquid Jets
Farrokhpanah, Amirsaman
2016-01-01
Multiphase Smoothed Particle Hydrodynamics (SPH) method has been used to study the jet breakup phenomena. It has been shown that this method is well capable of capturing different jet breakup characteristics. The value obtained for critical Weber number here in transition from dripping to jetting is a very good match to available values in literature. Jet breakup lengths are also agreeing well with several empirical correlations. Successful usage of SPH, as a comparably fast CFD solver, in jet breakup analysis helps in speeding up the numerical study of this phenomenon.
Hall-effect thruster--Cathode coupling: The effect of cathode position and magnetic field topology
Sommerville, Jason D.
2009-12-01
Hall-effect thruster (HET) cathodes are responsible for the generation of the free electrons necessary to initiate and sustain the main plasma discharge and to neutralize the ion beam. The position of the cathode relative to the thruster strongly affects the efficiency of thrust generation. However, the mechanisms by which the position affects the efficiency are not well understood. This dissertation explores the effect of cathode position on HET efficiency. Magnetic field topology is shown to play an important role in the coupling between the cathode plasma and the main discharge plasma. The position of the cathode within the magnetic field affects the ion beam and the plasma properties of the near-field plume, which explains the changes in efficiency of the thruster. Several experiments were conducted which explored the changes of efficiency arising from changes in cathode coupling. In each experiment, the thrust, discharge current, and cathode coupling voltage were monitored while changes in the independent variables of cathode position, cathode mass flow and magnetic field topology were made. From the telemetry data, the efficiency of the HET thrust generation was calculated. Furthermore, several ion beam and plasma properties were measured including ion energy distribution, beam current density profile, near-field plasma potential, electron temperature, and electron density. The ion beam data show how the independent variables affected the quality of ion beam and therefore the efficiency of thrust generation. The measurements of near-field plasma properties partially explain how the changes in ion beam quality arise. The results of the experiments show that cathode position, mass flow, and field topology affect several aspects of the HET operation, especially beam divergence and voltage utilization efficiencies. Furthermore, the experiments show that magnetic field topology is important in the cathode coupling process. In particular, the magnetic field
Breakup conditions of projectile spectators from dynamical observables
Energy Technology Data Exchange (ETDEWEB)
Begemann-Blaich, M.; Lindenstruth, V.; Pochodzalla, J. [and others
1998-03-01
Momenta and masses of heavy projectile fragments (Z {>=} 8), produced in collisions of {sup 197}Au with C, Al, Cu and Pb targets at E/A=600 MeV, were determined with the ALADIN magnetic spectrometer at SIS. Using these informations, an analysis of kinematic correlations between the two and three heaviest projectile fragments in their rest frame was performed. The sensitivity of these correlations to the conditions at breakup was verified within the schematic SOS-model. For a quantitative investigation, the data were compared to calculations with statistical multifragmentation models and to classical three-body calculations. With classical trajectory calculations, where the charges and masses of the fragments are taken from a Monte Carlo sampling of the experimental events, the dynamical observables can be reproduced. The deduced breakup parameters, however, differ considerably from those assumed in the statistical multifragmentation models which describe the charge correlations. If, on the other hand, the analysis of kinematic and charge correlations is performed for events with two and three heavy fragments produced by statistical multifragmentation codes, a good agreement with the data is found with the exception that the fluctuation widths of the intrinsic fragment energies are significantly underestimated. A new version of the multifragmentation code MCFRAG was therefore used to investigate the potential role of angular momentum at the breakup stage. If a mean angular momentum of 0.75 {Dirac_h}/nucleon is added to the system, the energy fluctuations can be reproduced, but at the same time the charge partitions are modified and deviate from the data. (orig.)
Breakup conditions of projectile spectators from dynamical observables
International Nuclear Information System (INIS)
Momenta and masses of heavy projectile fragments (Z ≥ 8), produced in collisions of 197Au with C, Al, Cu and Pb targets at E/A=600 MeV, were determined with the ALADIN magnetic spectrometer at SIS. Using these informations, an analysis of kinematic correlations between the two and three heaviest projectile fragments in their rest frame was performed. The sensitivity of these correlations to the conditions at breakup was verified within the schematic SOS-model. For a quantitative investigation, the data were compared to calculations with statistical multifragmentation models and to classical three-body calculations. With classical trajectory calculations, where the charges and masses of the fragments are taken from a Monte Carlo sampling of the experimental events, the dynamical observables can be reproduced. The deduced breakup parameters, however, differ considerably from those assumed in the statistical multifragmentation models which describe the charge correlations. If, on the other hand, the analysis of kinematic and charge correlations is performed for events with two and three heavy fragments produced by statistical multifragmentation codes, a good agreement with the data is found with the exception that the fluctuation widths of the intrinsic fragment energies are significantly underestimated. A new version of the multifragmentation code MCFRAG was therefore used to investigate the potential role of angular momentum at the breakup stage. If a mean angular momentum of 0.75 ℎ/nucleon is added to the system, the energy fluctuations can be reproduced, but at the same time the charge partitions are modified and deviate from the data. (orig.)
Investigations of nuclear projectile break-up reactions
International Nuclear Information System (INIS)
The cross sections for radiative capture of α-particles, deuterons and protons by light nuclei at very low relative energies are of particular importance for the understanding of the nucleosynthesis of chemical elements and for determining the relative elemental abundances in stellar burning processes at various astrophysical sites. As example we quote the reactions α+d → 6Li+γ, α+3He → 7Be+γ, or α+12C → 16O+γ. As an alternative to the direct experimental study of these processes we consider the inverse process, the photodisintegration, by means of the virtual photons provided by a nuclear Coulomb field: Z+a → Z+b+c. The radiative capture process b+c → a+γ is related to the inverse process, the photodisintegration γ+a → b+c by the detailed balance theorem. Except for the extreme case very close to the threshold the phase space favours the photodisintegration cross section as compared to the radiative capture. The Coulomb dissociation cross section proves to be enhanced due to the large virtual photon number, seen by the passing projectile, and the kinematics of the process leads to particular advantages for studies of the interaction of the two break-up fragments at small relative energies Ebc. The conditions of dedicated experimental investigations are discussed and demonstrated by recent experimental and theoretical studies of the break-up of 156 MeV 6Li projectiles. In addition, a brief review about general features of break-up processes of light ions in the field of atomic nuclei is given. (orig.)
The Coupling Effect of Spatial Reticulated Shell Structure with Cables
Institute of Scientific and Technical Information of China (English)
MA Jun; ZHOU Dai; FU Xu-chen
2005-01-01
The spatial reticulated shell structure with cables (RSC) is a kind of coupling working system, which consists of flexible cables, reticulated shell structure (RS) and tower columns. The dynamic analysis of RSC based on the coupling model was carried out. Three kinds of elements such as the spatial bar element, cable element and beam element were introduced to analyze the reticulated shell, cable and tower column respectively. Furthermore,such parameter influences as structural boundary conditions, grid configuration, the span-to-depth ratio and the arrangement of cable system upon structural dynamics were analyzed. The structural vibration modes can be divided into four groups based on some numerical examples. And the frequencies in the same group are very close while the frequencies in different groups are different from each other obviously. It is clear that the sequence of the appearance of the each mode group heavily depends on the comparative stiffness of the tower column system, RS and cables.
Fano effect through parallel-coupled double Coulomb islands
International Nuclear Information System (INIS)
By means of the nonequilibrium Green function and equation of motion method, the electronic transport is theoretically studied through a parallel-coupled double quantum dot (DQD) in the presence of on-dot Coulomb interaction U. With focus on the quantum interference in the U-dominant parallel-coupled DQD, we find two types of Fano interferences in the conductance spectra. If the one-particle DQD bonding and antibonding bands are well separated from their Coulomb blockade counterparts, the main features of Fano interference in usual DQD systems are recovered with minor revisions. The most interesting is the hybridization between the antibonding state and the Coulomb counterpart of the bonding state, which gives rises to two new channels for Fano resonance. The Fano interference in the Coulomb hybridized systems can be controlled by the electrostatic and magnetic approaches, and exhibits properties quite different from what are reported in the noninteracting Fano-Anderson model
Modification of the Doppler effect due to the helicity-rotation coupling
Energy Technology Data Exchange (ETDEWEB)
Mashhoon, Bahram
2002-12-30
The helicity-rotation coupling and its current empirical basis are examined. The modification of the Doppler effect due to the coupling of photon spin with the rotation of the observer is considered in detail in connection with its applications in the Doppler tracking of spacecraft. Further implications of this coupling and the possibility of searching for it in the intensity response of a rotating detector are briefly discussed.
Effectiveness of psychiatric and counseling interventions On fertility rate in infertile couples
Ramezanzadeh F; Noorbala AA.; Malak Afzali H.; Abedinia N.; Rahimi A; Shariet M.; Rashidi B.; Tehraninajad A.; Sohravand F.; Bagheri M
2007-01-01
Background: Considering the psycho-social model of diseases, the aim of this study was to evaluate the effect of psychiatric intervention on the pregnancy rate of infertile couples.Methods: In a randomized clinical trial, 638 infertile patients referred to a university infertility clinic were evaluated. Among them, 140 couples with different levels of depression in at least one of the spouses were included in this substudy. These couples were divided randomly into two groups. The patients in ...
The Breakup of Temperature Inversions In Steep Valleys
Colette, A.; Street, R.
The purpose of this research is to model and provide a better understanding of tem- perature inversions breakup in steep valleys. The Advanced Regional Prediction Sys- tem (ARPS), a three-dimensional, compressible, and non-hydrostatic modeling tool developed by the Center for Analysis and Prediction of Storms at the University of Oklahoma was used. Many field studies indicate that the evolution of the convective and inversion layers are strongly dependant on the surrounding topography. In relatively open valleys, the convective boundary layer usually grows from the bottom of the valley while in steeper cases, the upslope morning winds affects the dynamic of the mixing layer resulting in the destruction of the inversion from its bottom and its top (see Whiteman 1980). ARPS allows one to perform accurate simulation of such situations. First, written in terrain following coordinates, it handles steep topographies; then its extensive radi- ation and surface flux packages provide a good treatment of land related processes. Moreover, ARPS accounts for the incidence angle of sunrays, differencing the ex- posed and non-exposed mountain slopes. However, it neglects the topographic shade which can delay the sunrise of a hour or more in steep valleys. A new subroutine described by Colette etal. 2002 is thus used to compute the projected shade on the surrounding topography. Simulations of temperature inversion breakup for various two-dimensional valleys are presented. The time scale of evolution of the mixing layer is in good agreement with field studies and, as expected, the convective boundary layer shows an asymmetry between east and west facing slopes. The different patterns of inversion breakup doc- umented by Whiteman are also reproduced. These simulations of idealized cases give a better understanding of inversion breakup in steep valleys. Our code is now being applied to a real case: the study of a peculiar wind, la Ora del Garda, caused by the interaction between a
Bubble breakup in two-dimensional Stokes flow
International Nuclear Information System (INIS)
A new class of exact solutions is reported for an evolving bubble in a two-dimensional slow viscous flow. It is observed that for an expanding bubble the interface grows smoother with time, whereas the contracting-bubble solutions display a tendency to form sharp corners (''near cusps'') for small values of surface tension. In the latter case, we also obtain analytic solutions that describe bubble breakup: For a large class of initial shapes, the interface will eventually develop a thin ''neck'' whose width goes to zero before the bubble is completely removed from the liquid
Chaotic behaviour as a signal of nuclear breakup
International Nuclear Information System (INIS)
The nuclear breakup process is studied under the assumption that the energy transfer between the target and the projectile nucleus in the peripheral collisions can induce a chaotic behaviour of the nuclear Fermi systems, provided by the matching between the Woods - Saxon wall frequency and the uni - nucleonic frequency oscillation. Such a behaviour could be emphasized by uni-nucleonic phase - space maps, Poincare maps, power spectra, autocorrelation function and Lyapunov exponents ranging the nuclear interaction time scale: 10-22 s - 10-23 s. It is also shown that this method could be applied for various different fields and problems regarding nuclear dynamics. (authors)
Couplings in multiphasic geo-materials: temperature and chemistry effects
International Nuclear Information System (INIS)
Transport of chemical components in soil through water is the major cause of pollution of the soil. This transport takes place around landfills and nuclear waste storage areas, tailings and mine wastes, and so on. A great number of these sites are unsaturated of water and in some cases heat can change the fate of chemical species, that lead us to a coupled problem. In this dissertation, numerical simulation with an existent thermo-hydro-mechanical model and theoretical modeling and numerical simulation of transport and interactions of one chemical species in multiphase media are presented. Integrated THM model in the Code-Aster is presented. Excavation, engineering barrier and thermal load of waste nuclear storage well are modeled. Verification of model is presented with these simulations. A thermo-hydro-mechanical behaviour coupled with chemical phenomena is presented with a fully coupled method that water, gas, chemical species and soil skeleton were considered as constituents and corresponding unknowns are temperature, water pressure, gas pressure, chemical concentration and displacements. For each constituent, mass balance equation and linear momentum equation are written and solved simultaneously to find related unknowns. The results of this model have been compared with the theoretical and experimental results existing in the literature. Furthermore, results of some applications of this model are included. Some areas where further work is required are identified. In particular, there is a need to perform experiments to obtain necessary soil parameters to permit accurate modelling of the heat and contaminant transport in unsaturated soils. (author)
Effects of system-bath coupling on Photosynthetic heat engine: A polaron master equation approach
Qin, M; Zhao, X L; Yi, X X
2016-01-01
In this paper, we apply the polaron master equation, which offers the possibilities to interpolate between weak and strong system-bath coupling, to study how system-bath couplings affect charge transfer processes in Photosystem II reaction center (PSII RC) inspired quantum heat engine (QHE) model in a wide parameter range. The effects of bath correlation and temperature, together with the combined effects of these factors are also discussed in details. The results show a variety of dynamical behaviours. We interpret these results in terms of noise-assisted transport effect and dynamical localization which correspond to two mechanisms underpinning the transfer process in photosynthetic complexes: One is resonance energy transfer and the other is dynamical localization effect captured by the polaron master equation. The effects of system-bath coupling and bath correlation are incorporated in the effective system-bath coupling strength determining whether noise-assisted transport effect or dynamical localization...
Wave packet analysis and break-up length calculations for an accelerating planar liquid jet
International Nuclear Information System (INIS)
This paper examines the process of transition to turbulence within an accelerating planar liquid jet. By calculating the propagation and spatial evolution of disturbance wave packets generated at a nozzle where the jet emerges, we are able to estimate break-up lengths and break-up times for different magnitudes of acceleration and different liquid to air density ratios. This study uses a basic jet velocity profile that has shear layers in both air and the liquid either side of the fluid interface. The shear layers are constructed as functions of velocity which behave in line with our CFD simulations of injecting diesel jets. The non-dimensional velocity of the jet along the jet centre-line axis is assumed to take the form V (t) = tanh(at), where the parameter a determines the magnitude of the acceleration. We compare the fully unsteady results obtained by solving the unsteady Rayleigh equation to those of a quasi-steady jet to determine when the unsteady effects are significant and whether the jet can be regarded as quasi-steady in typical operating conditions for diesel engines. For a heavy fluid injecting into a lighter fluid (density ratio ρair/ρjet = q < 1), it is found that unsteady effects are mainly significant at early injection times where the jet velocity profile is changing fastest. When the shear layers in the jet thin with time, the unsteady effects cause the growth rate of the wave packet to be smaller than the corresponding quasi-steady jet, whereas for thickening shear layers the unsteady growth rate is larger than that of the quasi-steady jet. For large accelerations (large a), the unsteady effect remains at later times but its effect on the growth rate of the wave packet decreases as the time after injection increases. As the rate of acceleration is reduced, the range of velocity values for which the jet can be considered as quasi-steady increases until eventually the whole jet can be considered quasi-steady. For a homogeneous jet (q = 1), the
MULTIPHASE DROPLET/SLUG BREAK-UP MECHANISM IN MICROFLUIDIC T-JUNCTIONS AT VARIOUS WEBER NUMBERS
Directory of Open Access Journals (Sweden)
Wan Leng (Dawn Leow
2011-10-01
Full Text Available Normal 0 false false false EN-MY X-NONE X-NONE The formation of immiscible liquid droplets, or slugs, in microchannels features the advantages of volume control and mixing enhancement over single-phase microflows. Although the applications of droplet-based microfluidics have been widely demonstrated, the fundamental physics governing droplet break-up remains an area of active research. This study defines an effective Weber (Weeff number that characterizes the interplay of interfacial tension, shear stress and channel pressure drop in driving slug formation in T-junction microchannel for a relative range of low, intermediate and high flow rates. The immiscible fluid system in this study consists of Tetradecane slug formation in Acetonitrile. The progressive deformation of slug interfaces during break-up events is observed. Experimental results indicate that, at a relatively low Weeff, clean slug break-up occurs at the intersection of the side and main channels. At intermediate Weeff, the connecting neck of the dispersed phase is stretched to a short and thin trail of laminar flow prior to breaking up a short distance downstream of the T-junction. At a relatively high Weeff, the connecting neck develops into a longer and thicker trail of laminar flow that breaks up further downstream of the main channel.
Effects of titanium-dental restorative alloy galvanic couples on cultured cells.
Bumgardner, J D; Johansson, B I
1998-01-01
The potential exists for titanium and amalgams to become galvanically coupled in the oral cavity. While low galvanic corrosion rates have been measured in vivo for titanium-amalgam or mercury-free alloy couples, concerns exist over released corrosion products and adverse tissue responses. It was hypothesized in this study that coupling titanium to amalgams or gallium alloys increased the release of metallic corrosion products and decreased cellular activity and function. The effects of titanium coupled and uncoupled to a conventional amalgam, palladium-enriched spherical high copper amalgam, a dispersed type high copper amalgam, and a mercury-free gallium alloy were evaluated in 24-h cell culture tests. Viability, proliferation, and collagen synthesis were evaluated by the uptake of neutral red, 3H-thymidine, and immunoassay of procollagen, respectively, and compared to cells not exposed to any test material. The gallium alloy-titanium couple resulted in significant decreases in cellular viability, proliferation, and collagen synthesis as compared to the other coupled and uncoupled samples. Few differences in the cellular responses of the other coupled and uncoupled samples were observed. Atomic absorption analyses indicated increased release of metal ions from the amalgam and gallium alloy samples coupled to titanium as compared to their uncoupled condition, although the differences were not always significant. Galvanic corrosion of amalgam-titanium couples in the long term may become significant, and further research is needed. Coupling the gallium alloy to titanium may result in increased galvanic corrosion and cytotoxic responses.
Analytical and numerical study on grating depth effects in grating coupled waveguide sensors
DEFF Research Database (Denmark)
Horvath, R.; Wilcox, L.C.; Pedersen, H.C.;
2005-01-01
. Analytical expressions are derived both for the position and width of the in-coupling peaks to illustrate the effects of grating depth on the guided mode resonances in grating coupled waveguide sensors. Numerical computations verify the model for shallow gratings both in terms of peak shape and position......The in-coupling process for grating-coupled planar optical waveguide sensors is investigated in the case of TE waves. A simple analytical model based on the Rayleigh-Fourier-Kiselev method is applied to take into account the depth of the grating coupler, which is usually neglected in the modeling...
Phase Synchronization of Coupled Rossler Oscillators: Amplitude Effect
Institute of Scientific and Technical Information of China (English)
LI Xiao-Wen; ZHENG Zhi-Gang
2007-01-01
Phase synchronization of two linearly coupled Rossler oscillators with parameter misfits is explored.It is found that depending on parameter mismatches,the synchronization of phases exhibits different manners.The synchronization regime can be divided into three regimes.For small mismatches,the amplitude-insensitive regime gives the phase-dominant synchronization; When the parameter misfit increases,the amplitudes and phases of oscillators are correlated,and the amplitudes will dominate the synchronous dynamics for very large mismatches.The lag time among phases exhibits a power law when phase synchronization is achieved.
Vawter, G. Allen
2008-02-26
A self-electrooptic effect device ("SEED") is integrated with waveguide interconnects through the use of vertical directional couplers. Light initially propagating in the interconnect waveguide is vertically coupled to the active waveguide layer of the SEED and, if the SEED is in the transparent state, the light is coupled back to the interconnect waveguide.
Break-up dynamics of fluctuating liquid threads.
Petit, Julien; Rivière, David; Kellay, Hamid; Delville, Jean-Pierre
2012-11-01
The thinning dynamics of a liquid neck before break-up, as may happen when a drop detaches from a faucet or a capillary, follows different rules and dynamic scaling laws depending on the importance of inertia, viscous stresses, or capillary forces. If now the thinning neck reaches dimensions comparable to the thermally excited interfacial fluctuations, as for nanojet break-up or the fragmentation of thermally annealed nanowires, these fluctuations should play a dominant role according to recent theory and observations. Using near-critical interfaces, we here fully characterize the universal dynamics of this thermal fluctuation-dominated regime and demonstrate that the cross-over from the classical two-fluid pinch-off scenario of a liquid thread to the fluctuation-dominated regime occurs at a well-defined neck radius proportional to the thermal length scale. Investigating satellite drop formation, we also show that at the level of the cross-over between these two regimes it is more probable to produce monodisperse droplets because fluctuation-dominated pinch-off may allow the unique situation where satellite drop formation can be inhibited. Nonetheless, the interplay between the evolution of the neck profiles from the classical to the fluctuation-dominated regime and the satellites' production remains to be clarified. PMID:23090994
Institute of Scientific and Technical Information of China (English)
刘涛; 徐祖雄; 赵钟涛; 马如璋; 胡天斗; 谢亚宁; 郭应焕
1997-01-01
The role of magnetoelastic coupling effects in nanocrystalline ferromagnets is investigated by means of high-field magnetization and Doppler-broadening spectrum measurements. For the nanocrystalline Fe73.5 Cu1Nb3-Si13 5B9 alloy, the results show that the pinning effects resulting from the quasidislocation dipole intensely influence the movement of domain wall; by coupling with the magnetostriction the defects-induced stress fields determine the magnetic properties at the early stage of crystallization. In view of the effective anisotropy and magnetoelastic coupling energy the optimal annealing conditions of alloys are discussed.
Propulsive effects of vortex coupling between parallel pulsed jets
Athanassiadis, Athanasios; Hart, Douglas
2015-11-01
For vehicles that use pulsed jet propulsion, nature provides inspiration for different ways to improve propulsive performance. Communities of marine invertebrates called salps improve the efficiency of cruising locomotion by aggregating into large multi-animal chains. In this process, the cylindrical animals physically connect to each other side-by-side to form an array of individual pulsed jets whose synchronous pulsing propels the entire chain forward. Some benefits of this chaining behavior can be described using existing models of pulsed jet propulsion for steady, cruising conditions. However, during unsteady conditions such as impulsive maneuvering at low speeds, it remains unclear how interactions between neighboring jets will affect the chain's propulsive performance. Using bench-top experiments, we investigate the unsteady interactions between two parallel pulsed jets. Under some conditions, the pulsed jets form vortex rings that coalesce before vortex formation is complete, coupling the hydrodynamics of the independent jets. We measure how different degrees of vortex coupling alter the energy and momentum transfer in the two-jet system. Finally, we explore the energy and momentum scalings that would guide the design of a vehicle using multi-jet maneuvering techniques. This work was supported by the Office of Naval Research.
Waveguide-coupled cavities for energy recovery linacs
Kurennoy, S. S.; Nguyen, D. C.; Young, L. M.
2004-08-01
A novel scheme for energy recovery linacs used as FEL drivers is proposed. It consists of two parallel beam lines, one for electron beam acceleration and the other for the used beam that is bent after passing through a wiggler. The used beam is decelerated by the structure and feeds the cavity fields. The main feature of the scheme is that RF cavities are coupled with waveguides between these two linacs. The waveguide cut through the two beam pipes provides an efficient mechanism for energy transfer. The superconducting RF cavities in the two accelerators can be shaped differently, with an operating mode at the same frequency. This provides HOM detuning and therefore reduces the beam break-up effects. Another advantage of the proposed two-beam scheme is easy tuning of the cavity coupling by changing the waveguide length.
Continuum-Discretized Coupled-Channels calculations with core excitation
de Diego, R; Lay, J A; Moro, A M
2013-01-01
The effect of core excitation in the elastic scattering and breakup of a two-body halo nucleus on a stable target nucleus is studied. The structure of the weakly-bound projectile is described in the weak-coupling limit, assuming a particle-rotor model. The eigenfunctions and the associated eigenvalues are obtained by diagonalizing this Hamiltonian in a square-integrable basis (pseudo- states). For the radial coordinate between the particle and the core, a transformed harmonic oscil- lator (THO) basis is used. For the reaction dynamics, an extension of the Continuum-Discretized Coupled-Channels (CDCC) method, which takes into account dynamic core excitation and deexci- tation due to the presence of non-central parts in the core-target interaction, is adapted to be used along with a pseudo-states (PS) basis.
Effects on the two-point correlation function from the coupling of quintessence to dark matter
Lee, Seokcheon; Ng, Kin-wang
2009-01-01
We investigate the effects of the nonminimal coupling between the scalar field dark energy (quintessence) and the dark matter on the two- point correlation function. It is well known that this coupling shifts the turnover scale as well as suppresses the amplitude of the matter power spectrum. However, these effects are too small to be observed when we limit the coupling strength to be consistent with observations. Since the coupling of quintessence to baryons is strongly constrained, species dependent coupling may arise. This results in a baryon bias that is dif- ferent from unity. Thus, we look over the correlation function in this coupled model. We find that even the non-coupled quintessence model gives the better fit to the correlation function compared to the cosmo- logical constant model. We are also able to observe the enhancement of the baryon acoustic oscillation (BAO) peak due to the increasing bias factor of baryon from this species dependent coupling. In order to avoid the damping effect of the BAO...
Directory of Open Access Journals (Sweden)
Randall Nicola P
2012-10-01
Full Text Available Abstract Background Agriculture has intensified over the last 50 years resulting in increased usage of fertilizers and agrochemicals, changes in cropping practices, land drainage and increased stocking rates. In Europe, this has resulted in declines in the quality of soils and waters due to increased run off and water pollution. Fifty percent of nitrates in European rivers are derived from agricultural sources in the UK this value is as high as 70%, where agriculture also contributes to approximately 28% of phosphates and 76% of sediments recorded in rivers. Catchments dominated by agricultural land use have increased levels of pesticides and bacterial pathogens. European member states have a policy commitment to tackle water pollution through the Water Framework Directive. An analysis of the effectiveness of water pollution mitigation measures should enable decision makers and delivery agencies to better facilitate catchment planning. The aim of this systematic review is to assess the effectiveness of slurry storage, cover/catch crops, woodland creation, controlled trafficking/break-up of compacted layers and buffer strips, as on farm mitigation measures, for delivering an improved water environment. Methods The systematic review will consist of a searchable systematic map database for all the named interventions. Where possible, quantitative analysis will be used to assess the effectiveness of interventions. Electronic databases, the internet, and organisational websites will be searched, and stakeholders will be contacted for studies that investigate the impact of the on-farm mitigation measures on water quality. All studies found will be assessed for suitability for inclusion in the next stage. Inclusion criteria will be based on subject, intervention, comparator and outcome. The details of included studies will be incorporated into the systematic map database, and studies scored for effectiveness of intervention and study design. Where
Effectively Blocked Mechanism in Quantum Tunnelling of n-Coupled Single-Molecular Magnets
Institute of Scientific and Technical Information of China (English)
CHEN Zhi-De
2005-01-01
@@ We present theoretical study on quantum tunnelling in n-coupled single-molecule magnets (SMMs) by spincoherent-state path integral. It is found that, due to weak coupling between SMMs, the tunnelling process involving more than one-spin-flip is effectively blocked and the main contribution to the relaxation of the magnetization comes from the tunnelling processes involving just one-spin-flip. Starting from the negative saturated magnetization, the effect of the antiferromagnetic on tunnelling coupling is found to be qualitatively different from the ferromagnetic coupling. A criterion is developed to determine both the nature and the strength of the exchange coupling from the position of the first resonance of a spherical sample with homogeneous magnetization.
Coupling effects in bilayer thick metal films perforated with rectangular nanohole arrays
Directory of Open Access Journals (Sweden)
Li Yuan
2013-09-01
Full Text Available The coupling effects in bilayer thick metal (silver films perforated with rectangular nanohole arrays are investigated using the finite-difference time-domain technique. Many interesting light phenomena are observed as the distance between the metal rectangular nanohole arrays varies. Coupling effects are found to play very important roles on the optical and electronic properties of bilayer metal rectangular nanohole arrays: antisymmetric coupling between surface plasmon polaritons near the top and bottom film plane, and antisymmetric coupling between localized surface plasmon resonances near the two long sides of the rectangular hole, are probably excited in each layer of bilayer metal rectangular nanohole arrays; antisymmetric and symmetric magnetic coupling probably occur between the metal rectangular nanohole arrays.
Analytical tool development for coarse break-up of a molten jet in a deep water pool
Energy Technology Data Exchange (ETDEWEB)
Moriyama, Kiyofumi [Thermohydraulic Safety Research Group, Japan Atomic Energy Agency (JAEA), 2-4 Shirakata-shirane, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan)]. E-mail: moriyama.kiyofumi@jaea.go.jp; Nakamura, Hideo [Thermohydraulic Safety Research Group, Japan Atomic Energy Agency (JAEA), 2-4 Shirakata-shirane, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan); Maruyama, Yu [Thermohydraulic Safety Research Group, Japan Atomic Energy Agency (JAEA), 2-4 Shirakata-shirane, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan)
2006-10-15
A computer code JASMINE-pre was developed for the prediction of premixing conditions of fuel-coolant interactions and debris bed formation behavior relevant to severe accidents of light water reactors. In JASMINE-pre code, a melt model which consists of three components of sub-models for melt jet, melt particles and melt pool, is coupled with a two-phase flow model derived from ACE-3D code developed at JAERI. The melt jet and melt pool models are one-dimensional representations of a molten core stream falling into a water pool and a continuous melt body agglomerated on the bottom, respectively. The melt particles generated by the melt jet break-up are modeled based on a Lagrangian grouped particle concept. Additionally, a simplified model pmjet was developed which considers only steady state break-up of the melt jet, cooling and settlement of particles in a stationary water pool. The FARO corium quenching experiments with a saturation temperature water pool and a subcooled water pool were simulated with JASMINE-pre and pmjet. JASMINE-pre reproduced the pressurization and fragmentation behavior observed in the experiments with a reasonable accuracy. Also, the influences of model parameters on the pressurization and fragmentation were examined. The calculation results showed a quasi-steady state phase of melt jet break-up during which the amount of molten mass contained in the premixture was kept almost constant, and the steady state molten premixed masses evaluated by JASMINE-pre and pmjet agreed well.
Aleksandrova, A. G.; Galushina, T. Yu.
2015-12-01
The paper describes the software package developed for the numerical simulation of the breakups of natural and artificial objects and algorithms on which it is based. A new software "Numerical model of breakups" includes models of collapse of the spacecraft (SC) as a result of the explosion and collision as well as two models of the explosion of an asteroid.
Restructuring and Break-Up of Two-Dimensional Aggregates in Shear Flow
Vassileva, Nikolina D.; Ende, van den Dirk; Mugele, Frieder; Mellema, Jorrit
2006-01-01
We consider single two-dimensional aggregates, containing glass particles, placed at a water/air interface. We have investigated the critical shear rate for break-up of aggregates with different sizes in a simple shear flow. All aggregates break-up nearly at the same shear rate (1.8 ± 0.2 s-1) indep
Light-particle multiplicity accompanying projectile breakup at 20 MeV/A
International Nuclear Information System (INIS)
A large-solid-angle array has been used to determine the multiplicity of Z = 1 and Z = 2 particles accompanying projectile breakup into two fragments each with 5 ≤ Z ≤ 8. The charge balance obtained shows that projectile breakup is not associated with an unusual charge transfer to the target. 13 refs., 1 fig
Sub-picosecond pulse break-up in an InGaAsP optical amplifier
DEFF Research Database (Denmark)
Romstad, Francis Pascal
1999-01-01
broadening and eventual break-up for input pulse energies on the order of picoJoules. This break-up is present in the gain region (6-14 dB), while for absorption (-6 dB) and transparency, pulse narrowing by a factor of two is evidenced. We observe that not only the amplitude is modulated, but also the linear...
Neutrino-Electron Scattering: Charge Radius and Effective Couplings
International Nuclear Information System (INIS)
In this work the neutral-current scattering cross-section for neutrinos on electrons is calculated assuming that a massive Dirac neutrino is characterized by a phenomenological parameters, a charge radius (r2) and the right-handed currents are present in the framework of a Left-Right symmetric model (LR). Using the CHARM II result for the charge radius of the muon-neutrino |(r2)| < 6.0 × 10−33 cm2, we place a bound on −7.9 × 10−33 cm2 ≤ (r2)LR ≤ 7.9 × 10−33 cm2. We discuss the relationship between the electron neutral couplings gveV and gveA and the LR model parameters
Strong-coupling effects in a plasma of confining gluons
Florkowski, Wojciech; Su, Nan; Tywoniuk, Konrad
2015-01-01
The plasma consisting of confining gluons resulting from the Gribov quantization of the SU(3) Yang-Mills theory is studied using non-equilibrium fluid dynamical framework. Exploiting the Bjorken symmetry and using linear response theory a general analytic expressions for the bulk and shear viscosity coefficients are derived. It is found that the considered system exhibits a number of properties similar to the strongly-coupled theories, where the conformality is explicitly broken. In particular, it is shown that, in the large temperature limit, bulk to shear viscosity ratio, scales linearly with the difference $1/3 - c_s^2$, where $c_s$ is the speed of sound. Results obtained from the analysis are in line with the interpretation of the quark-gluon plasma as an almost perfect fluid.
Drop Breakup in Fixed Bed Flows as Model Stochastic Flow Fields
Shaqfeh, Eric S. G.; Mosler, Alisa B.; Patel, Prateek
1999-01-01
We examine drop breakup in a class of stochastic flow fields as a model for the flow through fixed fiber beds and to elucidate the general mechanisms whereby drops breakup in disordered, Lagrangian unsteady flows. Our study consists of two parallel streams of investigation. First, large scale numerical simulations of drop breakup in a class of anisotropic Gaussian fields will be presented. These fields are generated spectrally and have been shown in a previous publication to be exact representations of the flow in a dilute disordered bed of fibers if close interactions between the fibers and the drops are dynamically unimportant. In these simulations the drop shape is represented by second and third order small deformation theories which have been shown to be excellent for the prediction of drop breakup in steady strong flows. We show via these simulations that the mechanisms of drop breakup in these flows are quite different than in steady flows. The predominant mechanism of breakup appears to be very short lived twist breakups. Moreover, the occurrence of breakup events is poorly predicted by either the strength of the local flow in which the drop finds itself at breakup, or the degree of deformation that the drop achieves prior to breakup. It is suggested that a correlation function of both is necessary to be predictive of breakup events. In the second part of our research experiments are presented where the drop deformation and breakup in PDMS/polyisobutylene emulsions is considered. We consider very dilute emulsions such that coalescence is unimportant. The flows considered are simple shear and the flow through fixed fiber beds. Turbidity, small angle light scattering, dichroism and microscopy are used to interrogate the drop deformation process in both flows. It is demonstrated that breakup at very low capillary numbers occurs in both flows but larger drop deformation occurs in the fixed bed flow. Moreover, it is witnessed that breakup in the bed occurs
National Aeronautics and Space Administration — The objective of the research proposed herein is to define the coupled (combined) effect of critical environments on the structural performance of composite...
Numerical simulation of jet breakup behavior by the lattice Boltzmann method
International Nuclear Information System (INIS)
In order to understand the jet breakup behavior of the molten core material into coolant during a core disruptive accident (CDA) for a sodium-cooled fast reactor (SFR), we simulated the jet breakup due to the hydrodynamic interaction using the lattice Boltzmann method (LBM). The applicability of the LBM to the jet breakup simulation was validated by comparison with our experimental data. In addition, the influence of several dimensionless numbers such as Weber number and Froude number was examined using the LBM. As a result, we validated applicability of the LBM to the jet breakup simulation, and found that the jet breakup length is independent of Froude number and in good agreement with the Epstein's correlation when the jet interface becomes unstable. (author)
Mutual Coupling Effects Analysis in a Cross-Rhombic Antenna Array
Directory of Open Access Journals (Sweden)
Jorge Sosa-Pedroza
2012-01-01
Full Text Available We present an analysis of mutual coupling effects on radiation pattern and individual coupling in a conformal array of cross rhombic antennas. Analysis is made using both full-wave simulation and numerical approaches implemented in Matlab. The array consists of a truncated hexagonal pyramid, with a cross rhombic antenna in each pyramidal face, including the one on the top, having a 7-antennas-array. Results of radiation pattern and S11 parameters are presented, showing mutual coupling effects among the elements.
Asymptotics of QCD traveling waves with fluctuations and running coupling effects
Energy Technology Data Exchange (ETDEWEB)
Beuf, Guillaume [Institut de Physique Theorique, CEA, IPhT, F-91191 Gif-sur-Yvette, CNRS, URA 2306 (France)], E-mail: guillaume.beuf@cea.fr
2008-09-15
Extending the Balitsky-Kovchegov (BK) equation independently to running coupling or to fluctuation effects due to pomeron loops is known to lead in both cases to qualitative changes of the traveling-wave asymptotic solutions. In this paper we study the extension of the forward BK equation, including both running coupling and fluctuations effects, extending the method developed for the fixed coupling case [E. Brunet, B. Derrida, A.H. Mueller, S. Munier, Phys. Rev. E 73 (2006) 056126, (cond-mat/0512021)]. We derive the exact asymptotic behavior in rapidity of the probabilistic distribution of the saturation scale.
Control Methods Using Cross-Coupling Effects for Suppression of Rotor/Stator Rubbing System
Shang Zhiyong; Zhang Haiying; Shaymurat Talgar
2015-01-01
This paper investigated the influence of cross-coupling effects on the rubbing-related dynamics of rotor/stator systems, The stability analysis on the synchronous full annular rub solution of a rotor/stator system, which includes both the dynamics of the stator and the deformation on the contact surface as well as the cross-coupling terms in velocities and displacements, is carried out. It is found that some cross-coupling effects will benefit the synchronous full annular rubs and some will n...
EFFECT OF UPER-STORY LINTEL BEAM HEIGHT ON THE BEHAVIOUR OF COUPLED SHEAR WALL
Directory of Open Access Journals (Sweden)
Hasan KAPLAN
1995-01-01
Full Text Available In multi-story buildings, shear walls are used against the horizontal loads because their stiffness are greater than those of columns. The lateral deflections of tall building structures due to earthquake or wind is important role on the damage of buildings during the earthquake. The effectiveness of coupled shear walls in resisting horizontal loading depends on strongly on the rigidty of the coupling beams. In this study, In this study, using by finite element the shear walls with coupled lintel beams are investigated. The effects of uperstory lintel beam rigidity on strength and deformation were determined.
Effects of Herzberg--Teller vibronic coupling on coherent excitation energy transfer
Zhang, Hou-Dao; Xu, Rui-Xue; Yan, YiJing
2016-01-01
In this work, we study the effects of non-Condon vibronic coupling on the quantum coherence of excitation energy transfer, via the exact dissipaton-equation-of-motion (DEOM) evaluations on excitonic model systems. Field-triggered excitation energy transfer dynamics and two dimensional coherent spectroscopy are simulated for both Condon and non-Condon vibronic couplings. Our results clearly demonstrate that the non-Condon vibronic coupling intensifies the dynamical electronic-vibrational energy transfer and enhances the total system-and-bath quantum coherence. Moreover, the hybrid bath dynamics for non-Condon effects enriches the theoretical calculation, and further sheds light on the interpretation of the experimental nonlinear spectroscopy.
Selecting the pre-detection characteristics for effective fiber coupling of entangled photon sources
Anwar, Ali; P, Chithrabhanu; Reddy, Salla Gangi; Lal, Nijil; Singh, R P
2016-01-01
Photon modes have an important role in characterizing the quantum sources of light. Proper coupling of various photon modes obtained in spontaneous parametric down conversion (SPDC) process in optical fibers is essential to generate an effective source of entangled photons. The two main pre-detection factors affecting the biphoton mode coupling in SPDC are the pump beam focusing parameter and the crystal thickness. We present the numerical and experimental results on the effect of pump focusi...
Galvanic corrosion and cytotoxic effects of amalgam and gallium alloys coupled to titanium.
Bumgardner, J D; Johansson, B I
1996-06-01
The aim of this study was to examine and compare the galvanic corrosion of a conventional, a dispersed high-copper, and a palladium-enriched spherical high-copper amalgam and a gallium alloy coupled to titanium in saline and cell culture solutions, and to evaluate the effects of the couples on cultured cells. The potentials and charge transfers between amalgams and titanium were measured by electrochemical corrosion methods. Cytotoxicity of the couples, as indicated by the uptake of neutral red vital stain, was determined in 24-h direct contact human gingival fibroblast cell cultures. Results of this study indicated that before connecting the high-copper amalgams to titanium, the amalgams exhibited more positive potentials which resulted in initial negative charge transfers, i.e. corrosion of titanium. However, this initial corrosion appeared to cause titanium to passivate, and a shift in galvanic currents to positive charge transfers, i.e. corrosion of the amalgam samples. Lower galvanic currents were measured for the amalgam-titanium couples as compared to the gallium alloy-titanium couple. Coupling the conventional or the palladium-enriched high-copper amalgams to titanium did not significantly affect the uptake of neutral red as compared to cells not exposed to any test alloy. However, significant cytotoxic effects were observed when the dispersed-type high-copper amalgam and the gallium alloy were coupled to titanium. Even though the corrosion currents measured for these couples were less than gold alloys coupled to amalgam, these results suggest there is the potential for released galvanic corrosion products to become cytotoxic. These data warrant further investigations into the effects of coupling amalgam and gallium alloys to titanium in the oral environment.
The Kondo and Fano Effects in Triple Quantum Dots Coupled to Noncollinear Ferromagnetic Leads
Institute of Scientific and Technical Information of China (English)
HUANG Rui; MING Shan-Wen; WANG Yong
2012-01-01
We use the equation-of-motion technique and non-equilibrium Green's function theory to study the Kondo effect and the Fano effect in triple quantum dots (QDs) coupled to symmetrically ferromagnetic leads whose magnetic moments are noncollinear. We address the question of how the noncollinear ferromagnetic leads influence the Kondo effect and how the side-coupled QDs present Fano interference. The results show that the spin splitting of the density of state (DOS) takes place in an intermediate direction between the magnetic moments in the two leads. When interdot coupling strength ti is nonzero, Fano interference begins to play a major role in complicating the DOS of QD0.%We use the equation-of-motion technique and non-equilibrium Green's function theory to study the Kondo effect and the Fano effect in triple quantum dots (QDs) coupled to symmetrically ferromagnetic leads whose magnetic moments are noncollinear.We address the question of how the noncollinear ferromagnetic leads influence the Kondo effect and how the side-coupled QDs present Fano interference.The results show that the spin splitting of the density of state (DOS) takes place in an intermediate direction between the magnetic moments in the two leads.When interdot coupling strength ti is nonzero,Fano interference begins to play a major role in complicating the DOS of QD0.
Rotating Rig Development for Droplet Deformation/Breakup and Impact Induced by Aerodynamic Surfaces
Feo, A.; Vargas, M.; Sor, A.
2012-01-01
This work presents the development of a Rotating Rig Facility by the Instituto Nacional de Tecnica Aeroespacial (INTA) in cooperation with the NASA Glenn Research Center. The facility is located at the INTA installations near Madrid, Spain. It has been designed to study the deformation, breakup and impact of large droplets induced by aerodynamic bodies. The importance of these physical phenomena is related to the effects of Supercooled Large Droplets in icing clouds on the impinging efficiency of the droplets on the body, that may change should these phenomena not be taken into account. The important variables and the similarity parameters that enter in this problem are presented. The facility's components are described and some possible set-ups are explained. Application examples from past experiments are presented in order to indicate the capabilities of the new facility.
Hindered magnetic dipole transitions between P-wave bottomonia and coupled-channel effects
Guo, Feng-Kun; Meißner, Ulf-G.; Yang, Zhi
2016-09-01
In the hindered magnetic dipole transitions of heavy quarkonia, the coupled-channel effects originating from the coupling of quarkonia to a pair of heavy and anti-heavy mesons can play a dominant role. Here, we study the hindered magnetic dipole transitions between two P-wave bottomonia, χb (nP) and hb (n‧ P), with n ≠n‧. In these processes the coupled-channel effects are expected to lead to partial widths much larger than the quark model predictions. We estimate these partial widths which, however, are very sensitive to unknown coupling constants related to the vertices χb0 (nP) B B bar . A measurement of the hindered M1 transitions can shed light on the coupled-channel dynamics in these transitions and hence on the size of the coupling constants. We also suggest to check the coupled-channel effects by comparing results from quenched and fully dynamical lattice QCD calculations.
The effects of dual-channel coupling on the transition from amplitude death to oscillation death
Chen, Jiangnan; Liu, Weiqing; Zhu, Yun; Xiao, Jinghua
2016-07-01
Oscillation quenching including amplitude death (AD) and oscillation death (OD) in addition to the transition processes between them have been hot topics in aspect of chaos control, physical and biological applications. The effects of dual-channel coupling on the AD and OD dynamics regimes, and their transition processes in coupled nonidentical oscillators are explored numerically and theoretically. Our results indicate that an additional repulsive coupling tends to shrink the AD domain while it enlarges the OD domain, however, an additional attractive coupling acts inversely. As a result, the transitions from AD to OD are replaced by transitions from oscillation state (OS) to AD or from OS to OD in the dual-channel coupled oscillators with different frequency mismatches. Our results are helpful to better understand the control of AD and OD and their transition processes.
Investigation on the effect of aperture sizes and receiver positions in coupled rooms.
Xiang, Ning; Escolano, Jose; Navarro, Juan M; Jing, Yun
2013-06-01
Some recent concert hall designs have incorporated coupled reverberation chambers to the main hall that have stimulated a range of research activities in architectural acoustics. The coupling apertures between two or more coupled-volume systems are of central importance for sound propagation and sound energy decays throughout the coupled-volume systems. In addition, positions of sound sources and receivers relative to the aperture also have a profound influence on the sound energy distributions and decays. This work investigates the effect of aperture size on the behavior of coupled-volume systems using both acoustic scale-models and diffusion equation models. In these physical and numerical models, the sound source and receiver positions relative to the aperture are also investigated. Through systematic comparisons between results achieved from both physical scale models and numerical models, this work reveals valid ranges and limitations of the diffusion equation model for room-acoustic modeling. PMID:23742351
Elastic scattering, fusion, and breakup of light exotic nuclei
Energy Technology Data Exchange (ETDEWEB)
Kolata, J.J. [University of Notre Dame, Physics Department, Notre Dame, IN (United States); Guimaraes, V. [Universidade de Sao Paulo, Instituto de Fisica, Sao Paulo, SP (Brazil); Aguilera, E.F. [Instituto Nacional de Investigaciones Nucleares, Departamento de Aceleradores, Mexico, Distrito Federal (Mexico)
2016-05-15
The present status of fusion reactions involving light (A< 20) radioactive projectiles at energies around the Coulomb barrier (E<10 MeV per nucleon) is reviewed, emphasizing measurements made within the last decade. Data on elastic scattering (providing total reaction cross section information) and breakup channels for the involved systems, demonstrating the relationship between these and the fusion channel, are also reviewed. Similarities and differences in the behavior of fusion and total reaction cross section data concerning halo nuclei, weakly-bound but less exotic projectiles, and strongly-bound systems are discussed. One difference in the behavior of fusion excitation functions near the Coulomb barrier seems to emerge between neutron-halo and proton-halo systems. The role of charge has been investigated by comparing the fusion excitation functions, properly scaled, for different neutron- and proton-rich systems. Possible physical explanations for the observed differences are also reviewed. (orig.)
Equation of state of hot nuclei before break-up
International Nuclear Information System (INIS)
Following the method developed by the authors, recently, the equation of state of hot nuclei (238U* in concrete) before break-up was investigated numerically. The isotherms are drawn in the plane of the general pressure P versus volume VRT. They are similar to those of Van der Waals gas. The critical temperature of phase transition should correspond to the isotherm with one truning point only. It turns out that the data of mas yield distribution can be reproduced by many pairs of parameters T and VRT (freeze-out temperature and freezeout volume) varying in certain range. For each isotherm (each T), the data are always best reproduced by the value of VRT located at the maximum general pressure within two phases coexistence region
Inadvertent Earth Reentry Breakup Analysis for the New Horizons Mission
Ling, Lisa M.; Salama, Ahmed; Ivanov, Mark; McRonald, Angus
2007-01-01
The New Horizons (NH) spacecraft was launched in January 2006 aboard an Atlas V launch vehicle, in a mission to explore Pluto, its moons, and other bodies in the Kuiper Belt. The NH spacecraft is powered by a Radioisotope Thermoelectric Generator (RTG) which encases multiple General Purpose Heat Source (GPHS) modules. Thus, a pre-launch vehicle breakup analysis for an inadvertent atmospheric reentry in the event of a launch failure was required to assess aerospace nuclear safety and for launch contingency planning. This paper addresses potential accidental Earth reentries analyzed at the Jet Propulsion Laboratory (JPL) which may arise during the ascent to parking orbit, resulting in a suborbital reentry, as well as a departure from parking orbit, resulting in an orbital reentry.
Effect of Propellant Feed System Coupling and Hydraulic Parameters on Analysis of Chugging
Wood, Don J.; Dorsch, Robert G.
1967-01-01
A digital distributed parameter model was used to study the effects of propellant-feed- system coupling and various hydraulic parameters on the analytical prediction of chugging instabilities. Coupling between the combustion chamber and feed system was controlled by varying the compliance of the injector-dome region. The coupling with the feed system above the pump was varied by changing the amount of cavitation compliance at the pump inlet. The stability limits and chugging frequencies proved to be strongly dependent on the degree of feed-system coupling. The maximum stability condition occurred with intermediate coupling. Under conditions of a high degree of feed-system-combustor coupling, the stability limits and chugging frequencies were primarily dependent on the feed-system characteristics; the responses were characterized by beating patterns. For the system analyzed, the pump suction line had little effect on the stability limits or chugging frequencies. Beating, present under the condition of near zero injector -dome compliance, was eliminated when the suction line was decoupled by employing a sufficiently high value of pump-inlet compliance. Under conditions of maximum feed-system coupling, the magnitude and distribution of line losses in the discharge line had a significant effect on the stability limits but had negligible effect on the chugging frequency and beating characteristics. Also, the length of the discharge line greatly affected the stability limits, chugging frequency, and beating characteristics. The length of the suction line, however, had little effect on the stability limits and chugging frequency but did influence the beating pattern. A resistive-shunt device attached to the pump discharge line to suppress chugging was investigated. The analysis showed that the device was effective under conditions of high feed-system coupling.
AKR breakup and auroral particle acceleration at substorm onset
Morioka, A.; Miyoshi, Y.; Tsuchiya, F.; Misawa, H.; Yumoto, K.; Parks, G. K.; Anderson, R. R.; Menietti, J. D.; Donovan, E. F.; Honary, F.; Spanswick, E.
2008-09-01
The dynamical behavior of auroral kilometric radiation (AKR) is investigated in connection with auroral particle acceleration at substorm onsets using high-time-resolution wave spectrograms provided by Polar/PWI electric field observations. AKR develops explosively at altitudes above a preexisting low-altitude AKR source at substorm onsets. This "AKR breakup" suggests an abrupt formation of a new field-aligned acceleration region above the preexisting acceleration region. The formation of the new acceleration region is completed in a very short time (amplitude increases 10,000 times in 30 seconds), suggesting that the explosive development is confined to a localized region. AKR breakups are usually preceded (1-3 minutes) by the appearance and/or gradual enhancement of the low-altitude AKR. This means that the explosive formation of the high-altitude electric field takes place in the course of the growing low-altitude acceleration. The development of the low-altitude acceleration region is thus a necessary condition for the ignition of the high-altitude bursty acceleration. The dH/dt component from a search-coil magnetometer at ground shows that a few minutes prior to substorm onsets, the quasi-DC component begins a negative excursion that is nearly synchronized with the start of the gradual enhancement of the low-altitude AKR, indicating a precursor-like behavior for the substorm. This negative variation of dH/dt suggests an exponentially increasing ionospheric current induced by the upward field-aligned current. At substorm onsets, the decrease in the quasi-DC variation of dH/dt further accelerates, indicating a sudden reinforcement of the field-aligned current.
Influence of Improved Melt Breakup Model in Steam Explosion Simulation
Energy Technology Data Exchange (ETDEWEB)
Moriyamaa, Kiyofumi; Pakr, Hyun Sun [Pohang University of Science and Technology, Pohang (Korea, Republic of)
2015-10-15
In the steam explosion study, the melt particle size during premixing was given as a constant and a parametric survey was included to cover the bounding (maximum) values for the load or to cover a reasonable range of the uncertainty. For the coolability study, however, an empirical particle size distribution model was introduced into the code since it has a direct impact on the melt cooling behavior. A model for non-local (beyond cell) radiation heat transfer, which can be significant with high temperature melt materials (-3000K) and in relatively long range of time, was also implemented for that purpose. In this work, we revisited the steam explosion analysis with the code with such additional models and examined the influence of those models in the steam explosion simulation. Experiments with alumina and corium (UO{sub 2}- ZrO{sub 2} 80:20wt% mixture) melt, namely KROTOS-44 and FARO-L33 (hereafter K44 and L33) both performed at JRC-Ispra, EU, were referred to. Those data were also used for the validation of the original JASMINE. The simulation of steam explosion experiments with alumina and corium melts was revisited with improved melt breakup model that were introduced for the necessity in relatively long term melt jet breakup and cooling simulation. The model improvement included an empirical melt particle size distribution model and a simplified non-local (beyond cell) radiation heat transfer model. The influence of such models on the steam explosion simulation was not the same for two experiments with different melt materials, and we could not find one consistent set of model parameters with application of the newly introduced models to get satisfactory results on the simulation of both alumina and corium steam explosions.
Song, Yu-Shou; Hu, Li-Yuan; Liu, Hui-Lan; Wu, Hong-Yi
2015-01-01
The two-body core+$2n$ cluster structure was implemented to describe the two-neutron halo nucleus $^{\\mathrm{14}}\\mathrm{Be}$, where the core$^{\\mathrm{12}}\\mathrm{Be}$ was assumed inert and at ground state and the dineutron was assumed at pure $2S_0$ state. Based on such a structure the three-body continuum-discretized coupled-channel (CDCC) calculation was successfully used to deal with the $^{\\mathrm{14}}\\mathrm{Be}$ breakup reactions of $^{\\mathrm{14}}\\mathrm{Be}+^{\\mathrm{12}}\\mathrm{C}$ at 68~MeV/nucleon and $^{\\mathrm{14}}\\mathrm{Be}+ $Pb at 35~MeV/nucleon.Consequently, we modeled the kinematically complete measurement experiment of $^{\\mathrm{14}}\\mathrm{Be}$ (35~MeV/nucleon) Coulomb breakup at a lead target with the help of Geant4. From the simulation data the relative energy spectrum was constructed by the invariant mass method and $B(E1)$ spectrum was extracted using virtual photon model. The influence of the target thickness and detector performance on the spectroscopy was investigated.
Dielectric permittivity and temperature effects on spin-spin couplings studied on acetonitrile.
Sahakyan, Aleksandr B; Shahkhatuni, Astghik A; Shahkhatuni, Aleksan G; Panosyan, Henry A
2008-01-01
Dielectric permittivity (epsilon) and temperature effects on indirect spin-spin coupling constants were studied using acetonitrile as a probe molecule. Experiments were accompanied by hybrid DFT (density functional theory) studies, where the solvent was modeled using the polarization continuum model. Owing to its numerous types of J-couplings, acetonitrile is a very convenient molecule against which various basis sets can be tested or the best basis set can be selected for a given study. The results show reasonable agreement between calculated and experimental values. According to our data, scalar spin-spin coupling constants undergo substantial shifts at lower values of the dielectric constant. Thus J-coupling values are not transferable between measurements made at differing epsilon-conditions, and the assumption of the epsilon-independence of the J-coupling can lead to crucial mistakes in experiments using low-epsilon media. Dielectric permittivity also causes small geometric fluctuations within the molecule, which themselves can affect J-coupling values. Examinations of the results computed with frozen and relaxed geometries show that geometry mediation mostly affects the spin-dipole term of the J-coupling; hence, for accurate evaluation of the latter, frozen geometries are not acceptable. Another interesting fact revealed is the connection between the solvent dielectric properties and the temperature-dependence slopes of J-couplings in corresponding media. PMID:18098231
Effects of coupled dark energy on the Milky Way and its satellites
Penzo, Camilla; Macciò, Andrea V.; Baldi, Marco; Casarini, Luciano; Oñorbe, Jose; Dutton, Aaron A.
2016-09-01
We present the first numerical simulations in coupled dark energy cosmologies with high enough resolution to investigate the effects of the coupling on galactic and subgalactic scales. We choose two constant couplings and a time-varying coupling function and we run simulations of three Milky Way-sized haloes (˜1012 M⊙), a lower mass halo (6 × 1011 M⊙) and a dwarf galaxy halo (5 × 109 M⊙). We resolve each halo with several million dark matter particles. On all scales, the coupling causes lower halo concentrations and a reduced number of substructures with respect to Λ cold dark matter (ΛCDM). We show that the reduced concentrations are not due to different formation times. We ascribe them to the extra terms that appear in the equations describing the gravitational dynamics. On the scale of the Milky Way satellites, we show that the lower concentrations can help in reconciling observed and simulated rotation curves, but the coupling values necessary to have a significant difference from ΛCDM are outside the current observational constraints. On the other hand, if other modifications to the standard model allowing a higher coupling (e.g. massive neutrinos) are considered, coupled dark energy can become an interesting scenario to alleviate the small-scale issues of the ΛCDM model.
Tensor Coupling Effects on Spin Symmetry in the Anti-Lambda Spectrum of Hypernuclei
Institute of Scientific and Technical Information of China (English)
SONG Chun-Yan; YAO Jiang-Ming; MENG Jie
2011-01-01
Effects of △w-tensor coupling on the spin symmetry of A spectra in A-nucleus systems are studied using relativis-tic mean-field theory. Taking 12C+A as an example, it is found that the tensor coupling enlarges the spin-orbit splittings of A by a factor of 5 but has a negligible effect on the wave functions of A. Similar conclusions are observed in other A-nuclei, including 16O+A, 40Ca+A and 20SPb+A. It is indicated that the spin symmetry in anti-lambda-nucleus systems is still a good approximation irrespective of the tensor coupling.%@@ Effects of(∧∧)ω-tensor coupling on the spin symmetry of(∧)spectra in(∧)-nucleus systems are studied using relativis-tic mean-field theory.Taking 12C+(∧)as an example,it is found that the tensor coupling enlarges the spin-orbit splittings of(∧)a factor of 5 but has a negligible effect on the wave functions of(∧).Similar conclusions are observed in other(∧)-nuclei,including 16O+(∧),40Ca+(∧)and 20gPb+(∧).It is indicated that the spin symmetry in anti-lambdarnucleus systems is still a good approximation irrespective of the tensor coupling.
Magnetic domain wall creep in the presence of an effective interlayer coupling field
Energy Technology Data Exchange (ETDEWEB)
Metaxas, P.J. [Laboratoire de Physique des Solides, University of Paris-Sud, CNRS, UMR 8502, F-91405 Orsay Cedex (France); School of Physics, M013, University of Western Australia, 35 Stirling Hwy, Crawley, WA 6009 (Australia)], E-mail: metaxas@physics.uwa.edu.au; Jamet, J.P.; Ferre, J. [Laboratoire de Physique des Solides, University of Paris-Sud, CNRS, UMR 8502, F-91405 Orsay Cedex (France); Rodmacq, B.; Dieny, B. [SPINTEC, URA CNRS/CEA 2512, CEA-Grenoble, 38054 Grenoble Cedex 9 (France); Stamps, R.L. [School of Physics, M013, University of Western Australia, 35 Stirling Hwy, Crawley, WA 6009 (Australia)
2008-11-15
We investigate thermally activated domain wall creep in a system consisting of two ultrathin Co layers with perpendicular anisotropy coupled antiferromagnetically through a 4 nm thick Pt spacer layer. The field driven dynamics of domain walls in the softer Co layer have been measured while keeping the harder Co layer negatively saturated. The effect of the interlayer interaction on the soft layer is interpreted in terms of an effective coupling field, H{sub J}, which results in an asymmetry between the domain wall speeds measured under positive and negative driving fields. We show that creep theory remains valid to describe the observed wall motion when the effective coupling field is included in the creep velocity law as a component of the total field acting on the wall. Using the resultant modified creep expression, we determine a value for the effective coupling field which is consistent with that measured from the shift of the soft layer's minor hysteresis loop. The net antiferromagnetic coupling is attributed to a combination of RKKY and orange-peel coupling.
Magnetic domain wall creep in the presence of an effective interlayer coupling field
Metaxas, P. J.; Jamet, J. P.; Ferré, J.; Rodmacq, B.; Dieny, B.; Stamps, R. L.
We investigate thermally activated domain wall creep in a system consisting of two ultrathin Co layers with perpendicular anisotropy coupled antiferromagnetically through a 4 nm thick Pt spacer layer. The field driven dynamics of domain walls in the softer Co layer have been measured while keeping the harder Co layer negatively saturated. The effect of the interlayer interaction on the soft layer is interpreted in terms of an effective coupling field, HJ, which results in an asymmetry between the domain wall speeds measured under positive and negative driving fields. We show that creep theory remains valid to describe the observed wall motion when the effective coupling field is included in the creep velocity law as a component of the total field acting on the wall. Using the resultant modified creep expression, we determine a value for the effective coupling field which is consistent with that measured from the shift of the soft layer's minor hysteresis loop. The net antiferromagnetic coupling is attributed to a combination of RKKY and orange-peel coupling.
Fano-Kondo effect in the T-shaped double quantum dots coupled to ferromagnetic leads
Institute of Scientific and Technical Information of China (English)
Hou Tao; Wu Shao-Quan; Bi Ai-Hua; Yang Fu-Bin; Chen Jia-Feng; Fan Meng
2009-01-01
Using an equation-of-motion technique, we theoretically study the Fano-Kondo effect in the T-shaped double quantum dots coupled to two ferromagnetic leads by the Anderson Hamiltonian. We calculate the density of states in this system with both parallel and antiparallel lead-polarization alignments, and our results reveal that the interdot coupling, the spin-polarized strength and the energy level of the sidc coupled quantum dot greatly influence the density of states of the central quantum dot. This system is a possible candidate for spin valve transistors and may have potential applications in the spintronics.
COMPENSATION FOR THE EFFECTS OF MUTUAL COUPLING ON THE PERFORMANCE OF ADAPTIVE ARRAYS
Institute of Scientific and Technical Information of China (English)
Gao Xue; Hu Hongfei; Fu Demin
2002-01-01
Using the Method of Moments(MoM) and the spectral method, the effect of mutual coupling on the performance of adaptive arrays is compensated. First, the MoM is used to compute the behavior of the array, where the accurate analytical model and odd nnmbers of piecewise sinusoids are applied. Then the covariance matrix with mutual coupling being taken into account is analyzed, and the expression for the weight of the Least Mean Square(LMS)algorithm with mutual coupling being compensated is given. Finally, the method given in this letter is tested on an example.
Modulation of interlayer exchange coupling strength in magnetic tunnel junctions via strain effect
Energy Technology Data Exchange (ETDEWEB)
Jiang, Xin, E-mail: jiangxinyj@gmail.com; Li, Zhipeng; Zheng, Yuankai; Kaiser, Christian; Diao, Zhitao; Fang, Jason; Leng, Qunwen, E-mail: Qunwen.Leng@wdc.com [Western Digital Corporation, 44100 Osgood Road, Fremont, California 94539 (United States)
2015-09-15
Interlayer exchange coupling of two ferromagnetic electrodes separated by a thin MgO tunnel barrier is investigated using magneto-optical Kerr effect. We find that the coupling field can be reduced by more than 40% as the thickness of a top Ta capping layer increases from 0.5 to 1.2 nm. In contrast, a similar film stack with an additional 3 nm Ru capping layer displays no such dependence on Ta thickness. Transmission electron microscopy study shows that the oxidation of the exposed Ta capping layer induces changes in the crystalline structures of the underlying films, giving rise to the observed reduction of the interlayer coupling field.
Investigation of the effective aperture area of sliding and hinged doors between coupled spaces.
Luizard, Paul; Katz, Brian F G
2014-08-01
Acoustical coupling between architectural spaces can be implemented by sliding or hinged doors. This study compares the effects of these variable coupling area designs on the sound field using temporal energy decay curve analysis. Varying the aperture size alters the multi-slope decay curve properties such as the decay rate of each slope and their point of intersection (time and level). A predictive model is proposed, based on a geometrical approach and statistical theory for coupled volumes. Differences between scale model measurements and analytical predictions are quantified by means of deviations of acoustical parameters; reasonable agreement is found. PMID:25096137
Control Methods Using Cross-Coupling Effects for Suppression of Rotor/Stator Rubbing System
Directory of Open Access Journals (Sweden)
Shang Zhiyong
2015-01-01
Full Text Available This paper investigated the influence of cross-coupling effects on the rubbing-related dynamics of rotor/stator systems, The stability analysis on the synchronous full annular rub solution of a rotor/stator system, which includes both the dynamics of the stator and the deformation on the contact surface as well as the cross-coupling terms in velocities and displacements, is carried out. It is found that some cross-coupling effects will benefit the synchronous full annular rubs and some will not. Based on the finding, a control method by generating cross-coupling damping on the stator through the active auxiliary bearing is then proposed in order to suppress the contact severity and avoid the rubbing instability. Numerical simulation shows the validity of the mehtod.
Effect of coupling transformer on the performance of microwave ion source: simulation and experiment
International Nuclear Information System (INIS)
A 2.45 GHz high current microwave ion source is currently operational at VECC. It is able to produce more than 12 mA of beam current with just 300 watts of microwave power. The extracted beam current from the ion source depends strongly on the microwave coupling transformer. In order to understand the effect of microwave coupling on the performance of ion source, we have designed three different types of coupling transformers using ANSYS HFSS code, namely WR-284 waveguide and two double ridged waveguides one with 24 mm ridge width and another with 48 mm ridge width. We have fabricated these transformers and studied experimentally their effect on the extracted current from the ion source. This paper presents simulation details and experimental results of different microwave coupling transformers on performance of the ion source. (author)
Effects of network structure on the synchronizability of nonlinearly coupled Hindmarsh–Rose neurons
Energy Technology Data Exchange (ETDEWEB)
Li, Chun-Hsien, E-mail: chli@nknucc.nknu.edu.tw [Department of Mathematics, National Kaohsiung Normal University, Yanchao District, Kaohsiung City 82444, Taiwan (China); Yang, Suh-Yuh, E-mail: syyang@math.ncu.edu.tw [Department of Mathematics, National Central University, Jhongli District, Taoyuan City 32001, Taiwan (China)
2015-10-23
This work is devoted to investigate the effects of network structure on the synchronizability of nonlinearly coupled dynamical network of Hindmarsh–Rose neurons with a sigmoidal coupling function. We mainly focus on the networks that exhibit the small-world character or scale-free property. By checking the first nonzero eigenvalue of the outer-coupling matrix, which is closely related to the synchronization threshold, the synchronizabilities of three specific network ensembles with prescribed network structures are compared. Interestingly, we find that networks with more connections will not necessarily result in better synchronizability. - Highlights: • We investigate the effects of network structure on the synchronizability of nonlinearly coupled Hindmarsh–Rose neurons. • We mainly consider the networks that exhibit the small-world character or scale-free property. • The synchronizability of three specific network ensembles with prescribed network structures are compared. • Networks with more connections will not necessarily result in better synchronizability.
International Nuclear Information System (INIS)
To the second order in metric and the first order in equations of motion in the local coordinates of an accelerated rotating observer, the inertial effects and gravitational effects are simply additive. To look into the coupled inertial and gravitational effects, we derive the third-order expansion of the metric and the second-order expansion of the equations of motion in local coordinates. Besides purely gravitational (purely curvature) effects, the equations of motion contain, in this order, the following coupled inertial and gravitational effects: redshift corrections to electric, magnetic, and double-magnetic type curvature forces; velocity-induced special relativistic corrections; and electric, magnetic, and double-magnetic type coupled inertial and gravitational forces. An example is provided with a static observer in the Schwarzchild spacetime
Energy Technology Data Exchange (ETDEWEB)
Li, W.; Ni, W.
1979-07-01
To the second order in metric and the first order in equations of motion in the local coordinates of an accelerated rotating observer, the inertial effects and gravitational effects are simply additive. To look into the coupled inertial and gravitational effects, we derive the third-order expansion of the metric and the second-order expansion of the equations of motion in local coordinates. Besides purely gravitational (purely curvature) effects, the equations of motion contain, in this order, the following coupled inertial and gravitational effects: redshift corrections to electric, magnetic, and double-magnetic type curvature forces; velocity-induced special relativistic corrections; and electric, magnetic, and double-magnetic type coupled inertial and gravitational forces. An example is provided with a static observer in the Schwarzchild spacetime.
Tunable thermal entanglement in an effective spin-star system using coupled microcavities
Institute of Scientific and Technical Information of China (English)
Yang Wan-Li; Wei Hua; Feng Mang; An Jun-Hong
2009-01-01
We theoretically explore the possibility of realizing controllable thermal entanglement of effective spins in a fourqubit anisotropic Heisenberg XXZ coupling spin-star system constructed by coupled microcavities. We analyse the dependence of thermal entanglement in this system on temperature,inhomogeneity of the magnetic field,and anisotropy,which can be readily tuned via the external laser fields. The peculiar characteristic and the full controllability of the thermal entanglement are demonstrated to be useful for quantum information processing.
Effective-mass theory for coupled quantum dots grown on (11N)-oriented substrates
Institute of Scientific and Technical Information of China (English)
Li Shu-Shen; Xia Jian-Bai
2007-01-01
The electronic structures of coupled quantum dots grown on (11N)-oriented substrates are studied in the framework of effective-mass envelope-function theory. The results show that the all-hole subbands have the smallest widths and the optical properties are best for the (113), (114), and (115) growth directions. Our theoretical results agree with the available experimental data. Our calculated results are useful for the application of coupled quantum dots in photoelectric devices.
Zhou, Peng
2015-01-01
In a natural system, coupling effects among different physical fields substantially reflect the conversion of energy from one form to another. According to the law of conservation of energy (LCE), the loss of energy in one field must equal to the gain of energy in another field. In this paper, this LCE is applied to analyze the reversible processes coupled between elastic and electromagnetic fields. Here, it is called the energy formulation. For simple physical processes such as mechanical mo...
The Kaon electromagnetic form factor and effects of running coupling constant
International Nuclear Information System (INIS)
The Borel transform and resumed expression for the kaon electromagnetic form factor Fk(Q2) are obtained in the context of QCD running coupling αS(Q2(1-x) (1-y)) approach. It is demonstrated that effects of running coupling (infrared renormalons) can be taken into account by scale-setting procedure αS(Q2) → αS(ef(Q2)Q2) in the leading order expression. (author). 7 refs, 2 figs
Anomalous $tqZ$ coupling effects in rare B- and K-meson decays
Li, Xin-Qiang; Yuan, Xing-Bo
2011-01-01
As a top-factory, the LHC is performing a direct study of top-quark anomalous FCNC couplings, which are, however, correlated closely with the rare B- and K-meson decays. In this paper, we study the effects of anomalous $tqZ$ (with $q=u,c$) couplings in the rare decays $B_{s,d}\\to \\mu^+\\mu^-$, $B\\to X_s \
Numerical simulation of the effect of coupling support of bolt-mesh-anchor in deep tunnel
Institute of Scientific and Technical Information of China (English)
SUN Xiao-ming; CAI Feng; YANG Jun; CAO Wu-fu
2009-01-01
The mechanical effects of bolt-mesh-anchor coupling support in deep tunnels were studied by using a numerical method, based on deep tunnel coupling supporting techniques and non-linear deformation mechanical theory of rock mass at great depths. It is shown that the potential of a rigid bolt support can be efficiently activated through the coupling effect between a bolt-net support and the surrounding rock. It is found that the accumulated plastic energy in the surrounding rock can be sufficiently transformed by the coupling effect of a bolt-mesh-tray support. The strength of the surrounding rock mass can be mobilized to control the deformation of the surrounding rock by a pre-stress and time-space effect of the anchor support. The high stress transformation effect can be realized by the mechanical coupling effect of the bolt-mesh-anchor support, whereby the force of the support and deformation of the surrounding rock tends to become uniform, leading to a sustained stability of the tunnel.
Disintegration locations in 7Li→8Be transfer-triggered breakup at near-barrier energies
Simpson, E. C.; Cook, K. J.; Luong, D. H.; Kalkal, Sunil; Carter, I. P.; Dasgupta, M.; Hinde, D. J.; Williams, E.
2016-02-01
Background: At above-barrier energies, complete fusion cross sections in collisions of light weakly bound nuclei with heavy target nuclei are suppressed when compared to well-bound nuclei. Breakup of the projectilelike nucleus was proposed to be the cause. In addition to direct breakup, breakup following transfer was shown to be substantial. Purpose: We investigate breakup in reactions with 7Li, triggered by sub-barrier proton pickup to unbound states in 8Be, which subsequently separate into two α particles. Method: Measurements of sub-barrier disintegration of 7Li on a 58Ni target were made using the Heavy Ion Accelerator Facility at the Australian National University. Combining the experimental results with classical simulations of post-breakup acceleration, we study the sensitivity of α -α energy and angle correlations to the proximity of disintegration to the target (proton donor) nucleus. Results: The simulations indicate that disintegration as the colliding nuclei approach each other leads to large angular separations θ12 of the α fragments. The detectors allow for a maximum opening angle of θ12=132∘ , such that the present experiment is largely insensitive to breakup occurring when the collision partners approach each other. The data are consistent with disintegration of (a) the 0+8Be ground state far from the targetlike nucleus, and (b) the 2+8Be resonance near the targetlike nucleus when the 8Be is receding from the targetlike nucleus. Conclusions: The present results shed light on the near-target component of transfer-induced breakup reactions. The distribution of events with respect to the opening angle of the α particles, and the orientation of their relative velocity with respect to the velocity of their center of mass, gives insights into their proximity to the target at the moment of breakup. Further measurements with larger angular coverage and more complete simulations are required to fully understand the influence of breakup on fusion.
Cooley, Sarah; Pavelsky, Tamlin
2016-04-01
The annual spring breakup of river ice has important consequences for northern ecosystems and significant economic implications for Arctic industry and transportation. River ice breakup research is restricted by the sparse distribution of hydrological stations in the Arctic, where limited available data suggests a trend towards earlier ice breakup. The specific climatic mechanisms driving this trend, however, are complex and can vary both regionally and within river systems. Consequently, understanding the response of river ice processes to a warming Arctic requires simultaneous examination of spatial and temporal patterns in breakup timing. Here we present an automated algorithm for river ice breakup detection using MODIS satellite imagery that enables identification of spatial and temporal breakup patterns at large scales. We examine breakup timing on the Mackenzie, Lena, Ob' and Yenisey rivers for the period 2000-2014. First, we split each river into 10 km segments. Next, for each day of the breakup season, we classify each river pixel as snow/ice, mixed ice/water or open water based on MODIS reflectance values and remove all cloud-covered segments using the MODIS cloud product. We then define the breakup date as the first day where the segment is 75% open water. Using this method, we are able to determine breakup dates with a mean uncertainty of +/-1.3 days. We find our remotely sensed breakup dates to be highly correlated to ground breakup dates and the timing of peak discharge. All statistically significant temporal trends in breakup timing are negative, indicating an overall shift towards earlier breakup. Considerable variability in the statistical significance and magnitude of trends along each river suggests that different climatic and physiographic drivers are impacting spatial patterns in breakup. Trends detected on the lower Mackenzie corroborate recent studies indicating weakening ice resistance and earlier breakup timing near the Mackenzie Delta. In
Plasma effect in silicon charge coupled devices (CCDs)
Energy Technology Data Exchange (ETDEWEB)
Estrada, J., E-mail: estrada@fnal.gov [Fermi National Accelerator Laboratory, Batavia, IL 60510 (United States); Molina, J., E-mail: jmolina@ing.una.py [Facultad de Ingenieria, Universidad Nacional de Asuncion, Laboratorio de Mecanica y Energia, Campus de la UNA, San Lorenzo 2160 (Paraguay); Blostein, J.J., E-mail: jeronimo@cab.cnea.gov.ar [CONICET (Argentina); Centro Atomico Bariloche, Comision Nacional de Energia Atomica, Bariloche (Argentina); Fernandez, G., E-mail: fmoroni.guillermo@gmail.com [Universidad Nacional del Sur, Bahia Blanca (Argentina)
2011-02-11
Plasma effect is observed in CCDs exposed to heavy ionizing {alpha}-particles with energies in the range 0.5-5.5 MeV. The results obtained for the size of the charge clusters reconstructed on the CCD pixels agree with previous measurements in the high energy region ({>=}3.5 MeV). The measurements were extended to lower energies using {alpha}-particles produced by (n,{alpha}) reactions of neutrons in a {sup 10}B target. The effective linear charge density for the plasma column is measured as a function of energy. The results demonstrate the potential for high position resolution in the reconstruction of {alpha} particles, which opens an interesting possibility for using these detectors in neutron imaging applications.
Plasma effect in Silicon Charge Couple Devices (CCDs)
Estrada, Juan; Blostein, J
2011-01-01
Plasma effect is observed in CCDs exposed to heavy ionizing alpha-particles with energies in the range 0.5 - 5.5 MeV. The results obtained for the size of the charge clusters reconstructed on the CCD pixels agrees with previous measurements in the high energy region (>3.5 MeV). The measurements were extended to lower energies using alpha-particles produced by (n,alpha) reactions of neutrons in a Boron-10 target. The effective linear charge density for the plasma column is measured as a function of energy. The results demonstrate the potential for high position resolution in the reconstruction of alpha particles, which opens an interesting possibility for using these detectors in neutron imaging applications.
Anisotropic Paramagnetic Meissner Effect by Spin-Orbit Coupling
Espedal, Camilla; Yokoyama, Takehito; Linder, Jacob
2016-03-01
Conventional s -wave superconductors repel an external magnetic field. However, a recent experiment [A. Di Bernardo et al., Phys. Rev. X 5, 041021 (2015)] has tailored the electromagnetic response of superconducting correlations via adjacent magnetic materials. We consider another route of altering the Meissner effect where spin-orbit interactions induce an anisotropic Meissner response that changes sign depending on the field orientation. The tunable electromagnetic response opens new paths in the utilization of hybrid systems comprising magnets and superconductors.
Effect of the discretization and neutronic thermal hydraulic coupling on LWR transients
International Nuclear Information System (INIS)
Coupled multiphysics problems solve different physical phenomena with time scales of varying orders of magnitude. These phenomena are coupled in a nonlinear way making it difficult to find an accurate and efficient solution. Many of the present generation of codes for LWR are based on 3-D neutronic nodal methods coupled with first order thermal hydraulic methods. Moreover, the spatial and temporal meshes used to solve each field are different reflecting the scales of each phenomenon. This paper discusses the effect of the spatial and temporal discretization as well as the effect of different coupling schemes, with different level of implicitness, between the neutronic and core thermal hydraulics in SIMULATE-3K (S3K). S3K is a best estimate code used by many utilities, regulatory authorities and research institutes for the analysis of LWR transients that require the coupling of neutronic, fuel pin, and core hydraulic models. Examples of S3K applications are BWR stability analysis, fast anticipated operational occurrences, with or without scram, and reactivity initiated transients. Three different applications will be discussed in this paper to illustrate the effect of the discretization and coupling methods in multiphysics problems, namely: the NEA PWR rod ejection, the Ringhals-1 BWR stability, and the Peach Bottom turbine trip benchmarks. (author)
Directory of Open Access Journals (Sweden)
SOLANGE B. CAVALCANTI
2001-06-01
Full Text Available The simultaneous propagation of two optical pulses through a doped nonlinear dispersive medium modelled by a resonant three-level system was investigated numerically, within the framework of a pair of coupled extended nonlinear Schrödinger equations. These included the contribution of the dopant resonances whose dynamics is governed by Bloch equations. In this work, we review the interesting possibilities on the manipulation of fields such as cloning, breakup and soliton interactions, that the combination of coherent population trapping with nonlinear dispersive media offers.Investiga-se numericamente a propagação simultânea de dois pulsos ópticos através de um meio dispersivo não linear dopado, modelado por um sistema ressonante de três níveis, usando-se uma abordagem de equações generalizadas não lineares de Schrödinger. Estas últimas incluem a contribuição das ressonâncias do dopante cuja dinâmica é regida pelas equações de Bloch. Neste trabalho, revemos as possibilidades interessantes que a combinação de efeitos dispersivos não lineares com o aprisionamento coerente da população oferecem, tais como: clonagem, quebra e interação entre solitons.
Coulomb breakup of neutron-rich $^{29,30}$Na isotopes near the island of inversion
Rahaman, A; Aumann, T; Beceiro-Novo, S; Boretzky, K; Caesar, C; Carlson, B V; Catford, W N; Chakraborty, S; Chartier, M; Cortina-Gil, D; Angelis, G De; Gonzalez-Diaz, D; Emling, H; Fernandez, P Diaz; Fraile, L M; Ershova, O; Geissel, H; Jonson, B; Johansson, H; Kalantar-Nayestanaki, N; Krücken, R; Kröll, T; Kurcewicz, J; Langer, C; Bleis, T Le; Leifels, Y; Münzenberg, G; Marganiec, J; Nilsson, T; Nociforo, C; Nowacki, F; Najafi, A; Panin, V; Paschalis, S; Plag, R; Poves, A; Ray, I; Reifarth, R; Rigollet, C; Ricciardi, V; Rossi, D; Scheit, H; Simon, H; Scheidenberger, C; Typel, S; Taylor, J; Togano, Y; Volkov, V; Weick, H; Wagner, A; Wamers, F; Weigand, M; Winfield, J S; Yakorev, D; Zoric, M
2016-01-01
First results are reported on the ground state configurations of the neutron-rich $^{29,30}$Na isotopes, obtained via Coulomb dissociation (CD) measurements as a method of the direct probe. The invariant mass spectra of those nuclei have been obtained through measurement of the four-momentum of all decay products after Coulomb excitation on a $^{208}Pb$ target at energies of 400-430 MeV/nucleon using FRS-ALADIN-LAND setup at GSI, Darmstadt. Integrated Coulomb-dissociation cross-sections (CD) of 89 $(7)$ mb and 167 $(13)$ mb up to excitation energy of 10 MeV for one neutron removal from $^{29}$Na and $^{30}$Na respectively, have been extracted. The major part of one neutron removal, CD cross-sections of those nuclei populate core, in its' ground state. A comparison with the direct breakup model, suggests the predominant occupation of the valence neutron in the ground state of $^{29}$Na${(3/2^+)}$ and $^{30}$Na${(2^+)}$ is the $d$ orbital with small contribution in the $s$-orbital which are coupled with ground ...
Prediction and suppression of beam breakup instability in multicell superconducting cavities
Volkov, V.
2009-01-01
Beam breakup instability in superconducting cavities is a serious problem. In this work, a four-cell LEP cavity installed in the KAERI linear accelerator is considered as an example. Dependence of the breakup instability threshold currents on the characteristics of a dipole mode was determined both analytically and numerically. An efficient technique to suppress breakup instability using rf beam focusing within a cavity is suggested. The technique involves applying TE-type monopole higher-order modes and is useful for multicell superconducting cavities with many trapped high-Q dipole modes.
No-capture breakup and incomplete fusion reactions induced by stable weakly bound nucleus 9Be
Seyyedi, S. A.
2016-06-01
The reactions including the stable weakly bound nucleus 9Be have been studied using the classical trajectory model accompanied with the experimental breakup function and the Aage-Winther interaction potential (AW95). In these calculations, the no-capture breakup and the incomplete fusion cross-sections as well as their competition at around the Coulomb barrier have been investigated. Our calculations showed that at a given far-Coulomb-barrier energy the incomplete fusion reaction in different distributions of angular momentum and energies can dominate the no-capture breakup reaction. This dominating process is reversed at the near-barrier energies.
Concrete Damage and Neutralization under Coupling Effect of Carbonation and Freeze-thaw Cyeles
Institute of Scientific and Technical Information of China (English)
NIU Ditao; XIAO Qianhui; ZHU Wenping
2012-01-01
Simulating the coupling effect brought by freeze-thaw and carbonation environment,we experimentally investigated concrete durability,the variation characteristics of both concrete dynamic elastic modulus,and its neutralization depth.The influences imposed by carbonation on the freeze-thaw damage of concrete was studied as well and vise versa so as to shed light on the influencing mechanism together with the mutual interaction between them.The experimental results show that the damage caused by the coupling effect of freeze-thaw and carbonation on concrete is severer than any single effect of them two could bring.This provides certain theoretical references and paves down foundations for the further study in concrete durability related by the coupling environmental effect.
Jahn-Teller and spin-orbit coupling effects in transition-metal trifluorides
International Nuclear Information System (INIS)
Graphical abstract: Vibronic spectra for 5E' state of MnF3 using a two-mode Jahn-Teller Hamiltonian including spin-orbit coupling. Display Omitted Highlights: → Jahn-Teller potential-energy surfaces of 5E' states of MnF3 and CoF3 calculated. → The JT coupling parameters have been determined up to sixth order. → Vibronic spectra computed with two-mode JT Hamiltonian including spin-orbit coupling. → First ab initio study of the dynamical JT effect in transition-metal trifluorides. - Abstract: The effects of linear and higher-order Jahn-Teller couplings as well as spin-orbit coupling in orbitally degenerate electronic states of the transition-metal trifluorides MnF3 and CoF3 have been systematically explored with multi-configuration ab initio methods. The adiabatic potential-energy surfaces of low-lying 5E' and 5E'' states have been calculated with the CASSCF method. The spin-orbit coupling is described by matrix elements of the Breit-Pauli operator with nonrelativistic CASSCF wave functions. The Jahn-Teller coupling parameters of the Jahn-Teller active in-plane bending and stretching modes have been determined up to sixth order and fourth order, respectively, in the normal-mode expansion. Vibronic spectra have been computed, employing a Jahn-Teller Hamiltonian up to sixth order in the degenerate bending mode and fourth order in the degenerate stretching mode. These results represent the first ab initio study of the dynamical Jahn-Teller effect in transition-metal trifluorides with inclusion of spin-orbit coupling.
The Gate-Oxide Breakdown Effect Coupled by Channel Hot-Carrier-Effect in SOI MOSFET's
Institute of Scientific and Technical Information of China (English)
HAO Yue; ZHU Jiangang; REN Hongxia; ZHANG Weidong
2001-01-01
Based on SIMOS SOI devices, the gate-oxide breakdown effect coupled by channel hot carriers is studied in this paper. It is found that,in n-channel devices, the gate-oxide breakdown is at tributed to the fixed defect in SiO2 crystal lattice structure induced by high-energy hole injection into gate oxide. And the trapping of electron negative charge in gate oxide also accelerates the breakdown.While in PMOS devices, both local electric field in oxide enhancement caused by trapped electrons ,and the electric field on interface increasing induced by trapped holes and the generation of permanent damage in crystal lattice, can lead to gate oxide breakdown directly. The studies also show that the behavior after oxide layer broken down in NMOS and PMOS is different.
Effect of fatty acids on energy coupling processes in mitochondria.
Wojtczak, L; Schönfeld, P
1993-11-01
Long-chain fatty acids are natural uncouplers of oxidative phosphorylation in mitochondria. The protonophoric mechanism of this action is due to transbilayer movement of undissociated fatty acid in one direction and the passage of its anion in the opposite direction. The transfer of the dissociated form of fatty acid can be, at least in some kinds of mitochondrion, facilitated by adenine nucleotide translocase. Apart from dissipating the electrochemical proton gradient, long-chain fatty acids decrease the activity of the respiratory chain by mechanism(s) not fully understood. In intact cells and tissues fatty acids operate mostly as excellent respiratory substrates, providing electrons to the respiratory chain. This function masks their potential uncoupling effect which becomes apparent only under special physiological or pathological conditions characterized by unusual fatty acid accumulation. Short- and medium-chain fatty acids do not have protonophoric properties. Nevertheless, they contribute to energy dissipation because of slow intramitochondrial hydrolysis of their activation products, acyl-AMP and acyl-CoA. Long-chain fatty acids increase permeability of mitochondrial membranes to alkali metal cations. This is due to their ionophoric mechanism of action. Regulatory function of fatty acids with respect to specific cation channels has been postulated for the plasma membrane of muscle cells, but not demonstrated in mitochondria. Under cold stress, cold acclimation and arousal from hibernation the uncoupling effect of fatty acids may contribute to increased thermogenesis, especially in the muscle tissue. In brown adipose tissue, the special thermogenic organ of mammals, long-chain fatty acids promote operation of the unique natural uncoupling protein, thermogenin. As anionic amphiphiles, long-chain fatty acids increase the negative surface charge of biomembranes, thus interfering in their enzymic and transporting functions. PMID:8399375
Measurement of the reaction 2H(e,e') at 180 degrees close to the deuteron breakup threshold.
Ryezayeva, N; Arenhövel, H; Burda, O; Byelikov, A; Chernykh, M; Enders, J; Griesshammer, H W; Kalmykov, Y; von Neumann-Cosel, P; Ozel, B; Poltoratska, I; Pysmenetska, I; Rangacharyulu, C; Rathi, S; Richter, A; Schrieder, G; Shevchenko, A; Yevetska, O
2008-05-01
Inclusive inelastic electron scattering off the deuteron under 180 degrees has been studied at the S-DALINAC close to the breakup threshold at momentum transfers q=0.27 fm;{-1} and 0.74 fm;{-1} with good energy resolution sufficient to map in detail the spin flip M1 response, which governs the starting reaction pn-->dgamma of big-bang nucleosynthesis over most of the relevant temperature region. Results from potential model calculations and (for q=0.27 fm;{-1}) from pionless nuclear effective field theory are in excellent agreement with the data.
COUPLING EFFECT OF SEEPAGE FLOW AND RIVER FLOW ON THE BANK FAILURE
Institute of Scientific and Technical Information of China (English)
NING Bo; WU Shi-qiang; TAN Ye-fei; XIE Xing-hua; YAN Jun; YAN Zhong-min; GENG Yan-qiong
2011-01-01
On the basis of the generalized physical model of the riverbank,the experiments were conducted to study the mechanisms of riverbank failure under the coupling effect of seepage flow and river flow.The experimental setup was specially designed,as well as test point location,parameters and procedures,and the main influencing factors were analyzed affecting riverbank failure based on the failure types,the variations of pore water pressure and soil displacement.The results indicated that the coupling effect has different influences on the bank failure in three aspects:the failure type,the process and the extent.In addition,the river flow played a more important role than the seepage flow in the coupling effect on the bank failure.
Effect of node-degree correlation on synchronization of identical pulse-coupled oscillators.
LaMar, M Drew; Smith, Gregory D
2010-04-01
We explore the effect of correlations between the in and out degrees of random directed networks on the synchronization of identical pulse-coupled oscillators. Numerical experiments demonstrate that the proportion of initial conditions resulting in a globally synchronous state (prior to a large but finite time) is an increasing function of node-degree correlation. For those networks observed to globally synchronize, both the mean and standard deviation of time to synchronization are decreasing functions of node-degree correlation. Pulse-coupled oscillator networks with negatively correlated node degree often exhibit multiple coherent attracting states, with trajectories performing fast transitions between them. These effects of node-degree correlation on dynamics of pulse-coupled oscillators are consistent with aspects of network topology (e.g., the effect of node-degree correlation on the eigenvalues of the Laplacian matrix) that have been shown to affect synchronization in other contexts.
SU(2) low energy quark effective couplings in weak external magnetic field
Braghin, Fabio L
2016-01-01
In this work corrections to the usual flavor SU(2) Nambu-Jona-Lasinio coupling due to a weak external magnetic field are calculated by considering polarization in a one (dressed) gluon exchange mechanism for quark interactions. The quark field is splitted into two components, one that condenses and another one is a background field for interacting quarks, being that the former is integrated out. The resulting determinant is expanded for relatively large quark mass and small magnetic field, $(eB_0/{M^*}^2)<1$ by resolving magnetic field dependent low energy quark effective interactions. Besides corrections to the NJL and vector NJL effective couplings, different $B_0-$dependent effective couplings that break isospin and chiral symmetry emerge.
The Kondo and Fano Effects in Triple Quantum Dots Coupled to Noncollinear Ferromagnetic Leads
International Nuclear Information System (INIS)
We use the equation-of-motion technique and non-equilibrium Green's function theory to study the Kondo effect and the Fano effect in triple quantum dots (QDs) coupled to symmetrically ferromagnetic leads whose magnetic moments are noncollinear. We address the question of how the noncollinear ferromagnetic leads influence the Kondo effect and how the side-coupled QDs present Fano interference. The results show that the spin splitting of the density of state (DOS) takes place in an intermediate direction between the magnetic moments in the two leads. When interdot coupling strength ti is nonzero, Fano interference begins to play a major role in complicating the DOS of QD0. (condensed matter: electronic structure, electrical, magnetic, and optical properties)
Energy Technology Data Exchange (ETDEWEB)
Belov, P. A., E-mail: pavelbelov@gmail.com; Yakovlev, S. L., E-mail: yakovlev@cph10.phys.spbu.ru [St. Petersburg State University, Department of Computational Physics (Russian Federation)
2013-02-15
The process of neutron-deuteron scattering at energies above the deuteron-breakup threshold is described within the three-body formalism of Faddeev equations. Use is made of the method of solving Faddeev equations in configuration space on the basis of expanding wave-function components in the asymptotic region in bases of eigenfunctions of specially chosen operators. Asymptotically, wave-function components are represented in the form of an expansion in an orthonormalized basis of functions depending on the hyperangle. This basis makes it possible to orthogonalize the contributions of elastic-scattering and breakup channels. The proposed method permits determining scattering and breakup parameters from the asymptotic representation of the wave function without reconstructing it over the entire configuration space. The scattering and breakup amplitudes for states of total spin S = 1/2 and 3/2 were obtained for the s-wave Faddeev equation.
Study of direct and sequential break-up reactions in 6Li+ 112Sn system
International Nuclear Information System (INIS)
The 6Li projectile while moving in the field of a target nucleus can not only dissociate into α+d but it can also first exchange a few nucleon with the target and then break up into two fragments. Identification of all these processes is important to understand the break-up mechanism of 6Li projectile and also to find the origin of the high yield of alpha particle production in such a reaction. In this paper, we present the exclusive measurement of breakup cross sections in 6Li+112Sn reaction exploring the above possibilities. Cross sections for both sequential as well as direct breakup are measured and compared with the theoretical calculations. The measured elastic scattering angular distributions were used as a constraint to the potential parameters that were used in the calculations to explain both elastic scattering and the breakup processes simultaneously
Generalized breakup and coalescence models for population balance modelling of liquid-liquid flows
Traczyk, Marcin; Thompson, Chris
2015-01-01
Population balance framework is a useful tool that can be used to describe size distribution of droplets in a liquid-liquid dispersion. Breakup and coalescence models provide closures for mathematical formulation of the population balance equation (PBE) and are crucial for accu- rate predictions of the mean droplet size in the flow. Number of closures for both breakup and coalescence can be identified in the literature and most of them need an estimation of model parameters that can differ even by several orders of magnitude on a case to case basis. In this paper we review the fundamental assumptions and derivation of breakup and coalescence ker- nels. Subsequently, we rigorously apply two-stage optimization over several independent sets of experiments in order to identify model parameters. Two-stage identification allows us to estab- lish new parametric dependencies valid for experiments that vary over large ranges of important non-dimensional groups. This be adopted for optimization of parameters in breakup...
Bandyopadhyay, P; Sen, A; Kaw, P K
2016-01-01
The dispersion properties of low frequency dust acoustic waves in the strong coupling regime are investigated experimentally in an argon plasma embedded with a mixture of kaolin and $MnO_2$ dust particles. The neutral pressure is varied over a wide range to change the collisional properties of the dusty plasma. In the low collisional regime the turnover of the dispersion curve at higher wave numbers and the resultant region of $\\partial\\omega/\\partial k < 0$ are identified as signatures of dust-dust correlations. In the high collisional regime dust neutral collisions produce a similar effect and prevent an unambiguous identification of strong coupling effects.
Energy Technology Data Exchange (ETDEWEB)
Bandyopadhyay, P. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)], E-mail: pintu@ipr.res.in; Prasad, G.; Sen, A.; Kaw, P.K. [Institute for Plasma Research, Bhat, Gandhinagar 382428 (India)
2007-09-03
The dispersion properties of low frequency dust acoustic waves in the strong coupling regime are investigated experimentally in an argon plasma embedded with a mixture of kaolin and MnO{sub 2} dust particles. The neutral pressure is varied over a wide range to change the collisional properties of the dusty plasma. In the low collisional regime the turnover of the dispersion curve at higher wave numbers and the resultant region of {partial_derivative}{omega}/{partial_derivative}k<0 are identified as signatures of dust-dust correlations. In the high collisional regime dust neutral collisions produce a similar effect and prevent an unambiguous identification of strong coupling effects.
International Nuclear Information System (INIS)
The dispersion properties of low frequency dust acoustic waves in the strong coupling regime are investigated experimentally in an argon plasma embedded with a mixture of kaolin and MnO2 dust particles. The neutral pressure is varied over a wide range to change the collisional properties of the dusty plasma. In the low collisional regime the turnover of the dispersion curve at higher wave numbers and the resultant region of ∂ω/∂k<0 are identified as signatures of dust-dust correlations. In the high collisional regime dust neutral collisions produce a similar effect and prevent an unambiguous identification of strong coupling effects
Effective mass of the ground state of the strong-coupling exciton in a quantum well
Institute of Scientific and Technical Information of China (English)
Eerdunchaolu; Xin Wei
2009-01-01
The properties of the effective mass of the ground state of the exciton, for which the electron (hole) is strongly coupled with interface-optical (IO) phonons but weakly coupled with bulk-longitudinal-optical (LO) phonons in a quantum well, are studied by means of Tokuda's improved linear combination operator and a modified second Lee-Low-Pines transformation method. The results indicate that the contributions of the interaction between the electron (hole) and the different phonon branches to the effective mass are greatly different, and change with the well width and the relative position between the electron and the hole.
Effects of leakage inductances on magnetically-coupled impedance-source networks
DEFF Research Database (Denmark)
Siwakoti, Yam P.; Loh, Poh Chiang; Blaabjerg, Frede;
2014-01-01
Coupled inductors have lately been used with impedance-source networks for keeping their shoot-through times short, while providing higher voltage boosts. The parameter that is critical to the operation of such impedance network based converter with coupled inductors is the leakage inductances. H....... However, the role of leakage inductances and its effect on the converter performance is often overlooked. This paper analyzes the effects of leakage inductances and demonstrates experimentally how the presence of leakage inductances degrades the performance of the converter....
Isotope Effect on Electron-Phonon Coupling in Multiband Superconductor MgB2
Mou, Daixiang; Taufour, Valentin; Wu, Yun; Huang, Lunan; Bud'Ko, Serguei; Canfield, Paul; Kaminski, Adam
We systematically investigate the isotope effect of electron-phonon coupling in multi-band superconductor MgB2 by laser based Angle Resolved Photoemission Spectroscopy. The kink structure around 70 meV on two σ bands, which is caused by electron coupling to E2 g phonon mode, is shifted to higher binding energy in Mg10B2 than that in Mg11B2. The measured shifting energy of 3.5 meV is consistent with theoretical calculation based on harmonic phonon in MgB2. Our temperature dependent measurement also indicates the isotope effect of kink structure is not dependent on superconducting transition.
Measuring the area of tear film break-up by image analysis software
Pena-Verdeal, Hugo; García-Resúa, Carlos; Ramos, Lucía.; Mosquera, Antonio; Yebra-Pimentel, Eva; Giráldez, María. Jesús
2013-11-01
Tear film breakup time (BUT) test only examines the first break in the tear film, but subsequent tear film events are not monitored. We present a method of measuring the area of breakup after the appearance of the first breakup by using open source software. Furthermore, the speed of the rupture was determined. 84 subjects participated in the study. 2 μl volume of 2% sodium fluorescein was instilled using a micropipette. The subject was seated behind a slit-lamp using a cobalt blue filter together with a Wratten 12 yellow filter. Then, the tear film was recorded by a camera attached to the slit lamp. 4 frames of each video was extracted, the first rupture (BUT_0), breakup after 1 second (BUT_1), rupture after 2 seconds (BUT_2) and breakup before the last blink (BUT_F). Open source software of measurement based on Java (NIH ImageJ) was used to measure the number of pixels in areas of breakup. These areas were divided by the area of exposed cornea to obtain the percentage of ruptures. Instantaneous breakup speed was calculated for second 1 as the difference between BUT_1 - BUT_0, whereas instant speed for second 2 was BUT_2 - BUT_1. Mean area of breakup obtained was: BUT_0 = 0.26%, BUT_1 = 0.48%, BUT_2 = 0.79% and BUT_F = 1.61%. Break speed was 0.22 area/sec for second 1 and 0.31 area/sec for second 2, showing a statistical difference between them (p = 0.007). Post BUT analysis may be easily monitoring with the aid of this software.
A Genesis breakup and burnup analysis in off-nominal Earth return and atmospheric entry
Salama, Ahmed; Ling, Lisa; McRonald, Angus
2005-01-01
The Genesis project conducted a detailed breakup/burnup analysis before the Earth return to determine if any spacecraft component could survive and reach the ground intact in case of an off-nominal entry. In addition, an independent JPL team was chartered with the responsibility of analyzing several definitive breakup scenarios to verify the official project analysis. This paper presents the analysis and results of this independent team.
Drag-induced breakup mechanism for droplet generation in dripping within flow focusing microfluidics
Institute of Scientific and Technical Information of China (English)
Ping Wu; Zhaofeng Luo; Zhifeng Liu; Zida Li; Chi Chen; Lili Feng; Liqun He
2015-01-01
Based on viscous drag-induced breakup mechanism, a simple model was proposed to predict the dripping drop-let size as a function of controllable parameters in flow focusing micro devices. The size of thread before breakup was also investigated through laminar flow theory. Experiments and numerical simulations by VOF are carried out simultaneously to validate the theoretical analysis, showing that droplet size decreases rapidly with the in-crease of the flow rate ratio and capil ary number.
Sub-picosecond pulse break-up in an InGaAsP optical amplifier
DEFF Research Database (Denmark)
Romstad, Francis Pascal
broadening and eventual break-up for input pulse energies on the order of picoJoules. This break-up is present in the gain region (6-14 dB), while for absorption (-6 dB9 and transparency, pulse narrowing by a factor of two is evidenced. We observe that not only the amplitude is modulated, but also the linear...
Panjal Paleomagnetism: Implications for Early Permian Gondwana break-up
Stojanovic, D.; Aitchison, J.; Ali, J. R.; Ahmad, T.; Ahmad Dar, R.; Agarwal, A.; Roeder, T.
2013-12-01
The mid-Early Permian represents an important phase in Pangaea's development marking the time when the >13,000 km-long string of terranes that are collectively known as 'Cimmeria' separated from Gondwana's Tethyan margin (northern Africa-NE Arabia-northern India-NW and northern Australia). The ~289 Ma Panjal Traps of NW India (Kashmir) are one of a number of mafic suites (Abor, Sikkim etc.) that were erupted onto the Indian block possibly during the separation of the Lhasa/SE Qiangtang block. Herein, we report data from the first modern paleomagnetic study of the unit. Results from four quarry sections (15 individual cooling units) from a locality close to Srinagar together form a tectonically coherent sequence spanning 2-3 km of stratigraphy. The derived direction and paleopole yield key new information concerning (1) the Early Permian location of India, and by inference that of central Gondwana, and (2) inform debates related to Cimmeria's breakup from eastern Gondwana. Moreover, they provide a new independent control for assessing NW Greater India's extent prior to its collision with Asia and the amount of vertical-axis rotation this sector of the Himalayan range experienced in the mid to late Cenozoic.
Cheating, breakup, and divorce: is Facebook use to blame?
Clayton, Russell B; Nagurney, Alexander; Smith, Jessica R
2013-10-01
The purpose of the present study was to investigate the relationship between using the social networking site known as Facebook and negative interpersonal relationship outcomes. A survey of 205 Facebook users aged 18-82 was conducted using a 16-question online survey to examine whether high levels of Facebook use predicted negative relationship outcomes (breakup/divorce, emotional cheating, and physical cheating). It was hypothesized that those with higher levels of Facebook use would demonstrate more negative relationship outcomes than those with lower use. The study then examined whether these relationships were mediated by Facebook-related conflict. Furthermore, the researchers examined length of relationship as a moderator variable in the aforementioned model. The results indicate that a high level of Facebook usage is associated with negative relationship outcomes, and that these relationships are indeed mediated by Facebook-related conflict. This series of relationships only holds for those who are, or have been, in relatively newer relationships of 3 years or less. The current study adds to the growing body of literature investigating Internet use and relationship outcomes, and may be a precursor to further research investigating whether Facebook use attributes to the divorce rate, emotional cheating, and physical cheating.
Sequential three-body breakup of a CO 2 + beam
Rajput, Jyoti; Ablikim, U.; Zohrabi, M.; Jochim, Bethany; Berry, Ben; Carnes, K. D.; Esry, B. D.; Ben-Itzhak, I.
2016-05-01
The dissociative double ionization of a CO2+beam leading to the three-body fragmentation channel C+ + O+ + O+ can have its origin in either a sequential or concerted process. In case of the sequential mechanism, the first step is a two-body breakup into CO2+ + O+, followed by a second step wherein CO2+ further fragments into C+ + O+. The rotation of the CO2+ formed during the first step has been used to discriminate between the sequential and non-sequential mechanisms in experiments which employ multi-coincidence momentum imaging techniques for detecting recoil fragments. We propose a novel way to look at this discriminating feature in terms of the angle of rotation of the CO2+ intermediate. We will also discuss the implications on the measured momentum distribution of detecting indistinguishable fragments in a coincidence measurement. This work was supported by the Chemical Sciences, Geosciences, and Biosciences Division, Office of Basic Energy Sciences, Office of Science, U.S. Department of Energy. BJ was also supported by DOE-SCGF (DE-AC05-06OR23100).
Aerosol cluster impact and break-up : model and implementation.
Energy Technology Data Exchange (ETDEWEB)
Lechman, Jeremy B.
2010-10-01
In this report a model for simulating aerosol cluster impact with rigid walls is presented. The model is based on JKR adhesion theory and is implemented as an enhancement to the granular (DEM) package within the LAMMPS code. The theory behind the model is outlined and preliminary results are shown. Modeling the interactions of small particles is relevant to a number of applications (e.g., soils, powders, colloidal suspensions, etc.). Modeling the behavior of aerosol particles during agglomeration and cluster dynamics upon impact with a wall is of particular interest. In this report we describe preliminary efforts to develop and implement physical models for aerosol particle interactions. Future work will consist of deploying these models to simulate aerosol cluster behavior upon impact with a rigid wall for the purpose of developing relationships for impact speed and probability of stick/bounce/break-up as well as to assess the distribution of cluster sizes if break-up occurs. These relationships will be developed consistent with the need for inputs into system-level codes. Section 2 gives background and details on the physical model as well as implementations issues. Section 3 presents some preliminary results which lead to discussion in Section 4 of future plans.
Asteroid breakup linked to the Great Ordovician Biodiversification Event
Schmitz, Birger; Harper, David A. T.; Peucker-Ehrenbrink, Bernhard; Stouge, Svend; Alwmark, Carl; Cronholm, Anders; Bergström, Stig M.; Tassinari, Mario; Xiaofeng, Wang
2008-01-01
The rise and diversification of shelled invertebrate life in the early Phanerozoic eon occurred in two major stages. During the first stage (termed as the Cambrian explosion), a large number of new phyla appeared over a short time interval ~540Myrago. Biodiversity at the family, genus and species level, however, remained low until the second stage marked by the Great Ordovician Biodiversification Event in the Middle Ordovician period. Although this event represents the most intense phase of species radiation during the Palaeozoic era and led to irreversible changes in the biological make-up of Earth's seafloors, the causes of this event remain elusive. Here, we show that the onset of the major phase of biodiversification ~470Myrago coincides with the disruption in the asteroid belt of the L-chondrite parent body-the largest documented asteroid breakup event during the past few billion years. The precise coincidence between these two events is established by bed-by-bed records of extraterrestrial chromite, osmium isotopes and invertebrate fossils in Middle Ordovician strata in Baltoscandia and China. We argue that frequent impacts on Earth of kilometre-sized asteroids-supported by abundant Middle Ordovician fossil meteorites and impact craters-accelerated the biodiversification process.
Study of the effect of loop inductance on the RF transmission line to cavity coupling coefficient.
Lal, Shankar; Pant, K K
2016-08-01
Coupling of RF power is an important aspect in the design and development of RF accelerating structures. RF power coupling employing coupler loops has the advantage of tunability of β, the transmission line to cavity coupling coefficient. Analytical expressions available in literature for determination of size of the coupler loop using Faraday's law of induction show reasonably good agreement with experimentally measured values of β below critical coupling (β ≤ 1) but show large deviation with experimentally measured values and predictions by simulations for higher values of β. In actual accelerator application, many RF cavities need to be over-coupled with β > 1 for reasons of beam loading compensation, reduction of cavity filling time, etc. This paper discusses a modified analytical formulation by including the effect of loop inductance in the determination of loop size for any desired coupling coefficient. The analytical formulation shows good agreement with 3D simulations and with experimentally measured values. It has been successfully qualified by the design and development of power coupler loops for two 476 MHz pre-buncher RF cavities, which have successfully been conditioned at rated power levels using these coupler loops.
A dyadic analysis of relationships and health: does couple-level context condition partner effects?
Barr, Ashley B; Simons, Ronald L
2014-08-01
Adding to the growing literature explicating the links between romantic relationships and health, this study examined how both couple-level characteristics, particularly union type (e.g., dating, cohabiting, or marriage) and interracial pairing, and interpersonal characteristics (e.g., partner strain and support), predicted young adults' physical and mental health. Using dyadic data from a sample of 249 young, primarily Black couples, we hypothesized and found support for the importance of couple-level context, partner behavior, and their interaction in predicting health. Interracial couples (all Black/non-Black pairings) reported worse health than monoracial Black couples. Union type, however, did not directly predict health but was a significant moderator of partner strain. That is, the negative association between partner strain and self-reported health was stronger for cohabiting and married couples versus their dating counterparts, suggesting that coresidence, more so than marital status, may be important for understanding partner effects on physical health. For psychological distress, however, partner support proved equally beneficial across union types.
Study of the effect of loop inductance on the RF transmission line to cavity coupling coefficient
Lal, Shankar; Pant, K. K.
2016-08-01
Coupling of RF power is an important aspect in the design and development of RF accelerating structures. RF power coupling employing coupler loops has the advantage of tunability of β, the transmission line to cavity coupling coefficient. Analytical expressions available in literature for determination of size of the coupler loop using Faraday's law of induction show reasonably good agreement with experimentally measured values of β below critical coupling (β ≤ 1) but show large deviation with experimentally measured values and predictions by simulations for higher values of β. In actual accelerator application, many RF cavities need to be over-coupled with β > 1 for reasons of beam loading compensation, reduction of cavity filling time, etc. This paper discusses a modified analytical formulation by including the effect of loop inductance in the determination of loop size for any desired coupling coefficient. The analytical formulation shows good agreement with 3D simulations and with experimentally measured values. It has been successfully qualified by the design and development of power coupler loops for two 476 MHz pre-buncher RF cavities, which have successfully been conditioned at rated power levels using these coupler loops.
Directory of Open Access Journals (Sweden)
Riccardo Filadi
2016-06-01
Full Text Available Communication between organelles plays key roles in cell biology. In particular, physical and functional coupling of the endoplasmic reticulum (ER and mitochondria is crucial for regulation of various physiological and pathophysiological processes. Here, we demonstrate that Presenilin 2 (PS2, mutations in which underlie familial Alzheimer’s disease (FAD, promotes ER-mitochondria coupling only in the presence of mitofusin 2 (Mfn2. PS2 is not necessary for the antagonistic effect of Mfn2 on organelle coupling, although its abundance can tune it. The two proteins physically interact, whereas their homologues Mfn1 and PS1 are dispensable for this interplay. Moreover, PS2 mutants associated with FAD are more effective than the wild-type form in modulating ER-mitochondria tethering because their binding to Mfn2 in mitochondria-associated membranes is favored. We propose a revised model for ER-mitochondria interaction to account for these findings and discuss possible implications for FAD pathogenesis.
Tensor coupling effects on spin symmetry in anti-Lambda spectrum of hypernuclei
Song, Chunyan; Meng, Jie
2010-01-01
The effects of $\\bar\\Lambda\\bar\\Lambda\\omega$-tensor coupling on the spin symmetry of $\\bar{\\Lambda}$ spectra in $\\bar{\\Lambda}$-nucleus systems have been studied with the relativistic mean-field theory. Taking $^{12}$C+$\\bar{\\Lambda}$ as an example, it is found that the tensor coupling enlarges the spin-orbit splittings of $\\bar\\Lambda$ by an order of magnitude although its effects on the wave functions of $\\bar{\\Lambda}$ are negligible. Similar conclusions has been observed in $\\bar{\\Lambda}$-nucleus of different mass regions, including $^{16}$O+$\\bar{\\Lambda}$, $^{40}$Ca+$\\bar{\\Lambda}$ and $^{208}$Pb+$\\bar{\\Lambda}$. It indicates that the spin symmetry in anti-lambda-nucleus systems is still good irrespective of the tensor coupling.
The effect of psycho-educational strategies on marital conflict among dual-career couples
Directory of Open Access Journals (Sweden)
Mohammad Ghamari
2011-12-01
Full Text Available The aim of this study was to determine the effect of psycho--educational strategies on decreasing the components of marital conflict among dual-career couples. The method of research was experimental design. 11 couples were selected using random sampling and then were assigned into the groups of experimental and control. The experimental group participated in psycho-educational sessions. Data were collected using Barati and Sanai’s marital conflict questionnaire and analyzed using repeated measure test. Results showed that psycho-educational strategies are effective in decreasing all components of marital conflict among dual-career couples (p<0/01 except for two components of seeking child support and separating financial events.
[Coupling effects of water and chemical fertilizers on Hevea brasiliensis latex yield].
Hua, Yuan-Gang; Chen, Qiu-Bo; Lin, Zhao-Mu; Luo, Wei
2008-06-01
Water and nutrient are the two main factors limiting Hevea brasiliensis growth and its latex yield. With 17 year-old Clone SCATC 7-33-97 H. brasiliensis as test material, the coupling effects of water and chemical N, P and K fertilizers on latex yield were studied by general orthogonal rotation design of quadratic regression with four factors and five levels under field condition, and a regressive mathematical model was set up based on the latex yield by quadratic regression analysis. The results showed that all test coupling levels of water and chemical fertilizers had significant effects on the latex yield. The yield-increasing effect of test factors was in the order of N application rate > irrigation amount > P application rate > K application rate, while the coupling effect of water and chemical fertilizers was in the sequence of water and N > N and P > water and P > water and K. There was a negative coupling effect of K application rate and soil moisture content. For latex yield, the optimum application rates of chemical fertilizers were 476.39 kg x hm(-2) of urea, 187.70 kg x hm(-2) of superphosphate and 225.77 kg x hm(-2) of potassium chloride, and the optimum irrigation amount was to have 82.78% soil relative water content. PMID:18808010
The coupled effect of tides and stellar winds on the evolution of compact binaries
Repetto, Serena
2014-01-01
We follow the evolution of compact binaries under the coupled effect of tides and stellar winds until the onset of Roche-lobe overflow. These binaries contain a compact object (either a black-hole, a neutron-star, or a planet) and a stellar component. We integrate the full set of tidal equations, which are based on Hut's model for tidal evolution, and we couple them with the angular momentum loss in a stellar wind. Our aim is twofold. Firstly, we wish to highlight some interesting evolutionary outcomes of the coupling. When tides are coupled with a non-massive stellar wind, one interesting outcome is that in certain types of binaries, the stellar spin tends to reach a quasi-equilibrium state, where the effect of tides and wind are counteracting each other. When tides are coupled with a massive wind, we parametrize the evolution in terms of the decoupling radius, at which the wind decouples from the star. Even for small decoupling radii this \\emph{wind braking} can drive systems on the main sequence to Roche-l...
Selective effects of noise by stochastic multi-resonance in coupled cells system
Institute of Scientific and Technical Information of China (English)
2008-01-01
By investigating a stochastic model for intracellular calcium oscillations proposed by Hfer,we have analyzed the transmission behavior of calcium signaling in a one-dimensional two-way coupled hepatocytes system.It is shown that when the first cell is subjected to the external noise,the output signal-to-noise ratio(SNR) in the cell exhibits two maxima as a function of external noise intensity,indicating the occurrence of stochastic bi-resonance(SBR).It is more important that when cells are coupled together,the resonant behavior in the 1st cell propagates along the chain with different features through the coupling effect.The cells whose locations are comparatively close to or far from the 1st cell can show SBR,while the cells located in the middle position can display stochastic multi-resonance(SMR).Fur-thermore,the number of cells that can show SMR increases with coupling strength enhancing.These results indicate that the cells system may make an effective choice in response to external signaling induced by noise,through the mechanism of SMR by adjusting coupling strength.
Anomalous Triple Gauge Couplings in the Effective Field Theory Approach at the LHC
Falkowski, Adam; Greljo, Admir; Marzocca, David; Son, Minho
2016-01-01
We discuss how to perform consistent extractions of anomalous triple gauge couplings (aTGC) from electroweak boson pair production at the LHC in the Standard Model Effective Field Theory (SMEFT). After recasting recent ATLAS and CMS searches in $pp\\to WZ (WW) \\to \\ell' \
The Effect of the Family Training Program on Married Women's Couple-Burnout Levels
Sirin, Hatice Deveci; Deniz, M. Engin
2016-01-01
This study aims to investigate the effect of Modules 2 and 3 of the Family Communication Section of the Family Training Program as prepared by the Ministry of Family and Social Policies on married women's couple-burnout levels. The study group consists of 40 married women in total: 20 constituting the experimental group and the remaining 20…
Microscopic- versus Effective Coupling in N=2 Yang-Mills With Four Flavours
Sachs, I; Sachs, Ivo; Weir, Billy
2000-01-01
We determine the instanton corrections to the effective coupling in SU(2), N=2 Yang-Mills theory with four flavours to all orders. Our analysis uses the S(2,Z)-invariant curve and the two instanton contribution obtained earlier to fix the higher order contributions uniquely.
M.H. Knol; R. in 't Veld; H.C.M. Vorst; J.H. van Driel; G.J. Mellenbergh
2013-01-01
This experimental study concerned the effects of repeated students’ evaluations of teaching coupled with collaborative consultation on professors’ instructional skills. Twenty-five psychology professors from a Dutch university were randomly assigned to either a control group or an experimental group
Electromagnetically induced transparency and dynamic Stark effect in coupled quantum resonators
De Ponte, M A; Serra, R M; Moussa, M H Y
2004-01-01
In this work we reproduce the phenomenology of the electromagnetically induced transparency and dynamic Stark effect in a dissipative system composed by two coupled bosonic fields under linear and nonlinear amplification process. Such a system can be used as a quantum switch in networks of oscillators.
Effects of Unequal Couplings on Fidelity of a Quantum Controlled-Controlled-Not Gate
Institute of Scientific and Technical Information of China (English)
WU Yin-Zhong; SHI Cui-Hua; PAN Tao; LI Zhen-Ya
2009-01-01
By numerically solving the Schodinger equation of a three-nuclear-spin system, the effects of the non-uniform nearest-neighbor (NN) interaction on the fidelity of a quantum controlled-controlled-not (CCN) gate are investigated for a digital initial state and a superposition initial state respectively. It is found from our simulation that the ratio of the deviation of the NN coupling δJ to the NAT coupling J should be smaller than 0.0005 to ensure a high fidelity of the quantum CCN gate.
The effects of electronic delocalization in highly coupled mixed valence systems
Lear, Benjamin James
2007-01-01
The trinuclear ruthenium cluster RuO(OAc)₆L₃ (where L is an ancillary ligand) is used to make a variety of mixed valence compounds in which two or more clusters are joined together by an organic bridging ligand. The magnitude of electronic coupling in the mixed valance state of these compounds is quite large and the complexes reside on the Robin-Day class II/class III borderline. The large degree of coupling in these complexes gives rise to ultrafast electron transfer whose effects are observ...
MODEL OF CENTRIFUGAL EFFECT AND ATTITUDE MANEUVER STABILITY OF A COUPLED RIGID-FLEXIBLE SYSTEM
Institute of Scientific and Technical Information of China (English)
LI Zhi-bin; WANG Zhao-lin; WANG Tian-shu; LIU Ning
2005-01-01
The influences of nonlinear centrifugal force to large overall attitude motion of coupled rigid-flexible system was investigated. First the nonlinear model of the coupled rigidflexible system was deduced from the idea of "cenlrifugal potential field", and then the dynamic effects of the nonlinear centrifugal force to system attitude motion were analyzed by approximate calculation; At last, the Lyapunov function based on energy norm was selected,in the condition that only the measured values of attitude and attitude speed are available,and it is proved that the PD feedback control law can ensure the attitude stability during large angle maneuver.
Coupling effect of surface plasmon polaritons in single-negative lamellar heterostructure
Institute of Scientific and Technical Information of China (English)
Lin Zhou; Yongyuan Zhu
2008-01-01
Propagation characteristics of surface plasmon polaritons (SPPs) in the lamellar heterostructure, which is actually a SPP waveguide array, constructed by two kinds of single negative (SNG) material layers stacked alternatively are investigated. Based on the finite element method (FEM), the negative-refraction (NR) property is demonstrated when the electromagnetic wave penetrates through free space into such SNG lamellar structure. A clear view of the underlying physics of NR is presented qualitatively that is mainly related to the coupled SPPs. The strong coupling effect leads to the novel SPP dispersion curves and then the anomalous propagation characteristics.
Isovector channel of quark-meson-coupling model and its effect on symmetry energy
Energy Technology Data Exchange (ETDEWEB)
Wang, X.B. [School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Qi, C. [KTH (Royal Institute of Technology), Alba Nova University Center, SE-10691 Stockholm (Sweden); Xu, F.R., E-mail: frxu@pku.edu.cn [School of Physics and State Key Laboratory of Nuclear Physics and Technology, Peking University, Beijing 100871 (China); Center for Theoretical Nuclear Physics, National Laboratory for Heavy Ion Physics, Lanzhou 730000 (China)
2011-08-15
The non-relativistic approximation of the quark-meson-coupling model has been discussed and compared with the Skyrme-Hartree-Fock model which includes spin exchanges. Calculations show that the spin-exchange interaction has important effect on the descriptions of finite nuclei and nuclear matter through the Fock exchange. Also in the quark-meson-coupling model, it is the Fock exchange that leads to a nonlinear density-dependent isovector channel and changes the density-dependent behavior of the symmetry energy.
Effect of biquadratic coupling on current induced magnetization switching in Co/Cu/Ni-Fe nanopillar
Aravinthan, D.; Sabareesan, P.; Daniel, M.
2016-05-01
The effect of biquadratic coupling on spin current induced magnetization switching in a Co/Cu/Ni-Fe nanopillar device is investigated by solving the free layer magnetization switching dynamics governed by the Landau-Lifshitz-Gilbert-Slonczewski (LLGS) equation. The LLGS equation is numerically solved by using Runge-Kutta fourth order procedure for an applied current density of 5 × 1012 Am-2. Presence of biquadratic coupling in the ferromagnetic layers reduces the magnetization switching time of the nanopillar device from 61 ps to 49 ps.
Minomo, Kosho; Ogata, Kazuyuki
2015-01-01
We analyze $^{16}$O-$^{16}$O and $^{12}$C-$^{12}$C scattering with the microscopic coupled-channels method and investigate the coupled-channels and three-nucleon-force (3NF) effects on elastic and inelastic cross sections. In the microscopic coupled-channels calculation, the Melbourne g-matrix interaction modified according to the chiral 3NF effects is used. It is found that the coupled-channels and 3NF effects additively change both the elastic and inelastic cross sections. As a result, the coupled-channels calculation including the 3NF effects significantly improves the agreement between the theoretical results and the experimental data. The incident-energy dependence of the coupled-channels and 3NF effects is also discussed.
Directory of Open Access Journals (Sweden)
Elizabeth M. Carnicom
2014-10-01
Full Text Available Coupling reactions were performed to gauge the effect of the inclusion of a radical trap on the success of coupling reactions of monohalogenated polystyrene (PSX chains in atom transfer radical coupling (ATRC type reactions. The effect of both the specific radical trap chosen and the structure of the polymer chain end were evaluated by the extent of dimerization observed in a series of analogous coupling reactions. The commonly used radical trap 2-methyl-2-nitrosopropane (MNP showed the highest amounts of dimerization for PSX (X = Br, Cl compared to coupling reactions performed in its absence or with a different radical trap. A dinitroxide coupling agent was also studied with the extent of coupling nearly matching the effectiveness of MNP in RTA (Radical trap-assisted-ATRC reactions, while N-nitroso and electron rich nitroso coupling agents were the least effective. (2,2,6,6-Tetramethyl-piperin-l-yloxyl-capped PS (PS-TEMPO, prepared by NMP, was subjected to a coupling sequence conceptually similar to RTA-ATRC, but dimerization was not observed regardless of the choice of radical trap. Kinetic experiments were performed to observe rate changes on the coupling reaction of PSBr as a result of the inclusion of MNP, with substantial rate enhancements found in the RTA-ATRC coupling sequence compared to traditional ATRC.
Hartley, Sigan L; Papp, Lauren M; Blumenstock, Shari M; Floyd, Frank; Goetz, Greta L
2016-09-01
The vulnerability-stress-adaptation model guided this examination of the impact of daily fluctuations in the symptoms and co-occurring behavior problems of children with autism spectrum disorder (ASD) on parents' couple problem-solving interactions in natural settings and as these interactions spontaneously occur. A 14-day daily diary was completed by mothers and fathers in 176 families who had a child with ASD. On each day of the diary, parents separately reported on the child with ASD's daily level of symptoms and co-occurring behavior problems and the topic and level of negative affect in their most meaningful or important daily couple problem-solving interaction. Multilevel modeling was used to account for the within-person, within-couple nested structure of the data. Results indicated that many parents are resilient to experiencing a day with a high level of child ASD symptoms and co-occurring behavior problems and do not report more negative couple problem-solving interactions. However, household income, level of parental broader autism phenotype, and presence of multiple children with special care needs served as vulnerability factors in that they were related to a higher overall rating of negative affect in couple interactions and moderated the impact of reporting a day with a high level of child ASD symptoms and co-occurring behavior problems on next-day ratings of negative couple problem-solving interactions. The magnitude of these effects was small. Understanding mechanisms that support adaptive couple interactions in parents of children with ASD is critical for promoting best outcomes. (PsycINFO Database Record
Zhou, Peng
2015-01-01
In this paper, the law of conservation of energy is applied to analyze reversible and coupling processes between elastic and electromagnetic fields. This approach is here called the energy formulation. For simple physical processes such as mechanical movement, diffusion and electrodynamic process, it is shown their governing equations all satisfy the law of conservation of energy. Then, analysis is extended to coupling effects. First, it is found the constitutive equations of the linear direct and converse piezoelectric and piezomagnetic effects guarantee that energy is conserved during the conversion of energies. Second, analyses found that for the generalized Villari effects, the electromagnetic energy can be treated as an extra term in the generalized elastic energy. Third, both the laws of conservation of momentum and energy are used to analyze electrostriction and magnetostriction. It is argued that both of these strictive effects are induced by the Maxwell stress. In addition, their energy is purely ele...
Analysis of squeal noise and mode coupling instabilities including damping and gyroscopic effects
Hervé, Benjamin; Mahé, Hervé; Jezequel, Louis
2008-01-01
This paper deals with an audible disturbance known as automotive clutch squeal noise from the viewpoint of friction-induced mode coupling instability. Firstly, an auto-coupling model is presented showing a non-conservative circulatory effect originating from friction forces. Secondly, the stability of an equilibrium is investigated by determining the eigenvalues of the system linearized equations. The effects of the circulatory and gyroscopic actions are examined analytically and numerically to determine their influence on the stability region. Separate and combined effects are analysed with and without structural damping and important information is obtained on the role of each parameter and their interactions regarding overall stability. Not only is structural damping shown to be of primary importance, as reported in many previous works, this article also highlights a particular relationship with gyroscopic effects. A method of optimizing both the stability range and its robustness with respect to uncertain...
Simulating Chiral Magnetic and Separation Effects with Spin-Orbit Coupled Atomic Gases.
Huang, Xu-Guang
2016-01-01
The chiral magnetic and chiral separation effects-quantum-anomaly-induced electric current and chiral current along an external magnetic field in parity-odd quark-gluon plasma-have received intense studies in the community of heavy-ion collision physics. We show that analogous effects occur in rotating trapped Fermi gases with Weyl-Zeeman spin-orbit coupling where the rotation plays the role of an external magnetic field. These effects can induce a mass quadrupole in the atomic cloud along the rotation axis which may be tested in future experiments. Our results suggest that the spin-orbit coupled atomic gases are potential simulators of the chiral magnetic and separation effects. PMID:26868084
Onsager's Cross Coupling Effects in Gas Flows Confined to Micro-channels
Wang, Ruijie; Xu, Kun; Qian, Tiezheng
2016-01-01
In rarefied gases, mass and heat transport processes interfere with each other, leading to the mechano-caloric effect and thermo-osmotic effect, which are of interest to both theoretical study and practical applications. We employ the unified gas-kinetic scheme to investigate these cross coupling effects in gas flows in micro-channels. Our numerical simulations cover channels of planar surfaces and also channels of ratchet surfaces, with Onsager's reciprocal relation verified for both cases. For channels of planar surfaces, simulations are performed in a wide range of Knudsen number and our numerical results show good agreement with the literature results. For channels of ratchet surfaces, simulations are performed for both the slip and transition regimes and our numerical results not only confirm the theoretical prediction [Phys. Rev. Lett. 107, 164502 (2011)] for Knudsen number in the slip regime but also show that the off-diagonal kinetic coefficients for cross coupling effects are maximized at a Knudsen n...
Galvanic coupling and its effect on origin potential flotation system of sulfide minerals
Institute of Scientific and Technical Information of China (English)
顾帼华; 戴晶平; 王晖; 邱冠周
2004-01-01
The galvanic coupling formed in origin potential flotation systems of sulfide minerals can be divided into three types: sulfide mineral-sulfide mineral-water system; sulfide mineral-steel ball-water system; and sulfide mineral-sulfide mineral-collector system. In this paper, taking lead, zinc, iron sulfide mineral systems for examples,several models of galvanic coupling were proposed and the effects of galvanic coupling on flotation were discussed. A galvanic contact between galena (or sphalerite) and pyrite contributes to decreasing the content of zinc in lead concentrate, and enhances remarkably the absorption of collector on the galena surface. During grinding, due to galvanic interactions between minerals and steel medium, Fe(OH)3 formed covers on the cathodic mineral surface, affecting its floatability.
Study of turning takeoff maneuver in free-flying dragonflies: effect of dynamic coupling
Zeyghami, Samane
2015-01-01
Turning takeoff flights of several dragonflies were recorded during which a dragonfly takes off while changing the flight direction at the same time. Center of mass was elevated about 1-2 body lengths. Five of these maneuvers were selected for 3D body surface reconstruction and the body orientation measurement. In oppose to conventional banked turn model, which neglects interactions between the rotational motions, in this study we investigated the strength of the dynamic coupling by dividing pitch, roll and yaw angular accelerations into two contributions: one from aerodynamic torque and one from dynamic coupling effect. The latter term is referred to as Dynamic Coupling Acceleration (DCA). The DCA term can be measured directly from instantaneous rotational velocities of the insect. We found a strong correlation between pitch and yaw velocities at the end of each wingbeat and the time integral of the corresponding DCA term. Generation of pitch, roll and yaw torques requires different aerodynamic mechanisms an...
Using internal coupling activities to enhance the effectiveness of open innovation
DEFF Research Database (Denmark)
Burcharth, Ana Luiza de Araújo; Knudsen, Mette Præst; Søndergaard, Helle Alsted
This paper investigates the role of specific intra-organizational mechanisms in analyzing performance implications of openness by addressing two questions: does openness to innovation influence innovation performance? And if so, what organizational activities facilitate increased effectiveness...... of outbound open innovation is positively related to innovation profitability. Furthermore, the paper finds that the use of internal coupling activities mediates the relationship between openness and innovation profitability. The main result is that the benefits of open innovation are fully captured only when...... firms adopt a number of coupling activities that provide employees with time, autonomy and empowerment to conduct their work. The paper therefore contributes to the innovation management literature by developing the concept of internal coupling activities, testing these on a set of open innovation...
DOA Estimation under Unknown Mutual Coupling and Multipath with Improved Effective Array Aperture
Wang, Yuexian; Trinkle, Matthew; Ng, Brian W.-H.
2015-01-01
Subspace-based high-resolution direction of arrival (DOA) estimation significantly deteriorates under array manifold perturbation and rank deficiency of the covariance matrix due to mutual coupling and multipath propagation, respectively. In this correspondence, the unknown mutual coupling can be circumvented by the proposed method without any passive or active calibration process, and the DOA of the coherent signals can be accurately estimated accordingly. With a newly constructed matrix, the deficient rank can be restored, and the effective array aperture can be extended compared with conventional spatial smoothing. The proposed method achieves a good robustness and DOA estimation accuracy with unknown mutual coupling. The simulation results demonstrate the validity and efficiency of the proposed method. PMID:26670235
The effective U(1)-Higgs theory at strong coupling on optical lattices?
Bazavov, Alexei; Tsai, Shan-Wen; Meurice, Yannick
2014-01-01
We discuss the U(1)-Higgs model in two dimensions in the strongly coupled regime. If we neglect the plaquette interactions, we generate an effective theory where link variables are integrated out, producing 4-field operators. Plaquette interactions can be restored order by order as in recent calculations with staggered fermions. In the case of a SU(2) gauge theory with fermions, this strong coupling expansion can be related to the strong coupling expansion of Fermi-Hubbard models possibly implementable on optical lattice. We would like to provide a similar construction relating the U(1)-Higgs model to some Bose-Hubbard model. As a first step in this direction, we discuss a recent proposal to implement the O(2) model on optical lattices using a 87Rb and 41K Bose-Bose mixture of cold atoms.
Effects of Spin-Orbit Coupling on Jaynes-Cummings and Tavis-Cummings Models
Zhu, Chuanzhou; Pu, Han
2016-01-01
We consider ultracold atoms inside a ring optical cavity that supports a single plane-wave mode. The cavity field, together with an external coherent laser field, drives a two-photon Raman transition between two internal pseudo-spin states of the atom. This gives rise to an effective coupling between atom's pseudo-spin and external center-of-mass (COM) motion. For the case of a single atom inside the cavity, We show how the spin-orbit coupling modifies the static and dynamic properties of the Jaynes-Cummings (JC) model. In the case of many atoms in thermodynamic limit, we show that the spin-orbit coupling modifies the Dicke superradiance phase transition boundary and the non-superradiant normal phase may become reentrant in some regimes.
Structural-acoustic coupling effects on the non-vacuum packaging vibratory cylinder gyroscope.
Xi, Xiang; Wu, Xuezhong; Wu, Yulie; Zhang, Yongmeng; Tao, Yi; Zheng, Yu; Xiao, Dingbang
2013-01-01
The resonant shells of vibratory cylinder gyroscopes are commonly packaged in metallic caps. In order to lower the production cost, a portion of vibratory cylinder gyroscopes do not employ vacuum packaging. However, under non-vacuum packaging conditions there can be internal acoustic noise leading to considerable acoustic pressure which is exerted on the resonant shell. Based on the theory of the structural-acoustic coupling, the dynamical behavior of the resonant shell under acoustic pressure is presented in this paper. A finite element (FE) model is introduced to quantitatively analyze the effect of the structural-acoustic coupling. Several main factors, such as sealing cap sizes and degree of vacuum which directly affect the vibration of the resonant shell, are studied. The results indicate that the vibration amplitude and the operating frequency of the resonant shell will be changed when the effect of structural-acoustic coupling is taken into account. In addition, an experiment was set up to study the effect of structural-acoustic coupling on the sensitivity of the gyroscope. A 32.4 mV/°/s increase of the scale factor and a 6.2 Hz variation of the operating frequency were observed when the radial gap size between the resonant shell and the sealing cap was changed from 0.5 mm to 20 mm.
Effects of phonon-phonon coupling on properties of pygmy resonance in $^{124-132}$Sn
Arsenyev, N N; Voronov, V V; Van Giai, Nguyen
2012-01-01
Starting from an effective Skyrme interaction we study effects of phonon-phonon coupling on the low-energy electric dipole response in $^{124-132}$Sn. The QRPA calculations are performed within a finite rank separable approximation. The inclusion of two-phonon configurations gives a considerable contribution to low-lying strength. Comparison with available experimental data shows a reasonable agreement for the low-energy $E1$ strength distribution.
Tagani, M. Bagheri; Golsanamlou, Z.; Izadi, S; Soleimani, H. Rahimpour
2013-01-01
Thermoelectric properties of a C60 molecular transistor are studied using Green function formalism in linear response regime. A tight-binding model is used to investigate the effect of the dimerization and coupling geometry on the electrical conductance, thermopower, and figure of merit. Increase of the connection points between the molecule and electrodes results in decrease of the number of the peaks of the electrical conductance owing to the interference effects. In addition, oscillation o...
DEFF Research Database (Denmark)
Ingeman-Nielsen, Thomas
2006-01-01
The effect of electrode contact resistance and capacitive coupling on complex resistivity (CR) measurements is studied in this paper. An equivalent circuit model for the receiver is developed to describe the effects. The model shows that CR measurements are severely affected even at relatively lo...... the contact resistance artificially increased by resistors. The results emphasize the importance of keeping contact resistance low in CR measurements....
Field effects on the vortex states in spin-orbit coupled Bose-Einstein condensates
Xu, Liang-Liang; Liu, Yong-Kai; Feng, Shiping; Yang, Shi-Jie
2016-06-01
Multi-quantum vortices can be created in the ground state of rotating Bose-Einstein condensates with spin-orbit couplings. We investigate the effects of external fields, either a longitudinal field or a transverse field, on the vortex states. We reveal that both fields can effectively reduce the number of vortices. In the latter case we further find that the condensate density packets are pushed away in the horizontal direction and the vortices finally disappear to form a plane wave phase.
Influence of External Magnetic Field on Anomalous Skin Effects in Inductively Coupled Plasmas
Institute of Scientific and Technical Information of China (English)
MAO Ming; WANG You-Nian
2004-01-01
@@ Using a one-dimensional slab model, we study the influence of the external static magnetic field on the anomalous skin effects in the inductively coupled plasma. The rf electromagnetic field in the plasma is determined by solving the linearized Boltzmann equation incorporating with the Maxwell equations. The numerical results show that,due to the existence of the external magnetic field, the anomalous skin effects are greatly enhanced and the number of regions with negative absorption is decreased.
The Effects of In-Work Benefit Reform in Britain on Couples: Theory and Evidence
Francesconi, Marco; Rainer, Helmut; van der Klaauw, Wilbert
2007-01-01
This paper examines the effects of the Working Families' Tax Credit (WFTC) on couples in Britain. We develop a simple model of household decisions which explicitly accounts for the role played by the tax and benefit system. Its main implications are then tested using panel data from the British Household Panel Survey collected between 1991 and 2002. Overall, the financial incentives of the reform had negligible effects on a wide range of married mothers' decisions, such as eligible (working a...
Effects of phonon-phonon coupling on properties of pygmy resonance in 124-132Sn
Directory of Open Access Journals (Sweden)
Voronov V. V.
2012-12-01
Full Text Available Starting from an effective Skyrme interaction we study effects of phonon-phonon coupling on the low-energy electric dipole response in 124-132Sn. The QRPA calculations are performed within a finite rank separable approximation. The inclusion of two-phonon configurations gives a considerable contribution to low-lying strength. Comparison with available experimental data shows a reasonable agreement for the low-energy E1 strength distribution.
Thermal Impedance Model of High Power IGBT Modules Considering Heat Coupling Effects
Bahman, Amir Sajjad; Ma, Ke; Blaabjerg, Frede
2014-01-01
Thermal loading of Insulated Gate Bipolar Transistor (IGBT) modules is important for the reliability performance of power electronic systems, thus the thermal information of critical points inside module like junction temperature must be accurately modeled and predicted. Usually in the existing thermal models, only the self-heating effects of the chips are taken into account, while the thermal coupling effects among chips are less considered. This could result in inaccurate temperature estima...
Coupled transfers; Transferts couples
Energy Technology Data Exchange (ETDEWEB)
Nicolas, X.; Lauriat, G.; Jimenez-Rondan, J. [Universite de Marne-la-Vallee, Lab. d' Etudes des Transferts d' Energie et de Matiere (LETEM), 77 (France); Bouali, H.; Mezrhab, A. [Faculte des Sciences, Dept. de Physique, Lab. de Mecanique et Energetique, Oujda (Morocco); Abid, C. [Ecole Polytechnique Universitaire de Marseille, IUSTI UMR 6595, 13 Marseille (France); Stoian, M.; Rebay, M.; Lachi, M.; Padet, J. [Faculte des Sciences, Lab. de Thermomecanique, UTAP, 51 - Reims (France); Mladin, E.C. [Universitaire Polytechnique Bucarest, Faculte de Genie Mecanique, Bucarest (Romania); Mezrhab, A. [Faculte des Sciences, Lab. de Mecanique et Energetique, Dept. de Physique, Oujda (Morocco); Abid, C.; Papini, F. [Ecole Polytechnique, IUSTI, 13 - Marseille (France); Lorrette, C.; Goyheneche, J.M.; Boechat, C.; Pailler, R. [Laboratoire des Composites ThermoStructuraux, UMR 5801, 33 - Pessac (France); Ben Salah, M.; Askri, F.; Jemni, A.; Ben Nasrallah, S. [Ecole Nationale d' Ingenieurs de Monastir, Lab. d' Etudes des Systemes Thermiques et Energetiques (Tunisia); Grine, A.; Desmons, J.Y.; Harmand, S. [Laboratoire de Mecanique et d' Energetique, 59 - Valenciennes (France); Radenac, E.; Gressier, J.; Millan, P. [ONERA, 31 - Toulouse (France); Giovannini, A. [Institut de Mecanique des Fluides de Toulouse, 31 (France)
2005-07-01
This session about coupled transfers gathers 30 articles dealing with: numerical study of coupled heat transfers inside an alveolar wall; natural convection/radiant heat transfer coupling inside a plugged and ventilated chimney; finite-volume modeling of the convection-conduction coupling in non-stationary regime; numerical study of the natural convection/radiant heat transfer coupling inside a partitioned cavity; modeling of the thermal conductivity of textile reinforced composites: finite element homogenization on a full periodical pattern; application of the control volume method based on non-structured finite elements to the problems of axisymmetrical radiant heat transfers in any geometries; modeling of convective transfers in transient regime on a flat plate; a conservative method for the non-stationary coupling of aero-thermal engineering codes; measurement of coupled heat transfers (forced convection/radiant transfer) inside an horizontal duct; numerical simulation of the combustion of a water-oil emulsion droplet; numerical simulation study of heat and mass transfers inside a reactor for nano-powders synthesis; reduction of a combustion and heat transfer model of a direct injection diesel engine; modeling of heat transfers inside a knocking operated spark ignition engine; heat loss inside an internal combustion engine, thermodynamical and flamelet model, composition effects of CH{sub 4}H{sub 2} mixtures; experimental study and modeling of the evolution of a flame on a solid fuel; heat transfer for laminar subsonic jet of oxygen plasma impacting an obstacle; hydrogen transport through a A-Si:H layer submitted to an hydrogen plasma: temperature effects; thermal modeling of the CO{sub 2} laser welding of a magnesium alloy; radiant heat transfer inside a 3-D environment: application of the finite volume method in association with the CK model; optimization of the infrared baking of two types of powder paints; optimization of the emission power of an infrared
Garfinkel, Chaim I.; Oman, Luke David; Barnes, Elizabeth A.; Waugh, Darryn W.; Hurwitz, Margaret H.; Molod, Andrea M.
2013-01-01
A robust connection between the drag on surface-layer winds and the stratospheric circulation is demonstrated in NASA's Goddard Earth Observing System Chemistry-Climate Model (GEOSCCM). Specifically, an updated parameterization of roughness at the air-sea interface, in which surface roughness is increased for moderate wind speeds (4ms to 20ms), leads to a decrease in model biases in Southern Hemispheric ozone, polar cap temperature, stationary wave heat flux, and springtime vortex breakup. A dynamical mechanism is proposed whereby increased surface roughness leads to improved stationary waves. Increased surface roughness leads to anomalous eddy momentum flux convergence primarily in the Indian Ocean sector (where eddies are strongest climatologically) in September and October. The localization of the eddy momentum flux convergence anomaly in the Indian Ocean sector leads to a zonally asymmetric reduction in zonal wind and, by geostrophy, to a wavenumber-1 stationary wave pattern. This tropospheric stationary wave pattern leads to enhanced upwards wave activity entering the stratosphere. The net effect is an improved Southern Hemisphere vortex: the vortex breaks up earlier in spring (i.e., the spring late-breakup bias is partially ameliorated) yet is no weaker in mid-winter. More than half of the stratospheric biases appear to be related to the surface wind speed biases. As many other chemistry climate models use a similar scheme for their surface layer momentum exchange and have similar biases in the stratosphere, we expect that results from GEOSCCM may be relevant for other climate models.
Broadband Metallic Planar Microlenses in an Array: the Focusing Coupling Effect.
Yu, Yiting; Wang, Ping; Zhu, Yechuan; Diao, Jinshuai
2016-12-01
The microlens arrays (MLAs) are widely utilized for various applications. However, when the lens size and the spacing between two adjacent microlenses are of the length scale of the working wavelength, the diffraction effect plays a vital role in the final focusing performance. We suggest a kind of broadband metallic planar microlenses, based on which the ultra-compact microlens arrays are also constructed. The focusing coupling effect revealing for such devices is then investigated in detail by using the finite-difference time-domain (FDTD) method, with the emphasis on the changing spacing between adjacent microlenses, the working wavelength, the diameter of microlenses, and the array size. The results show that a larger spacing, a larger lens size, a shorter wavelength, or a smaller array scale can lead to a weaker focusing coupling effect. This research provides an important technological reference to design an array of metallic planar microlenses with the well-controlled focusing performance. PMID:26922796
Nuclear Density-Dependent Effective Coupling Constants in the Mean-Field Theory
Lee, J H; Lee, S J; Lee, Jae Hwang; Lee, Young Jae; Lee, Suk-Joon
1996-01-01
It is shown that the equation of state of nuclear matter can be determined within the mean-field theory of $\\sigma \\omega$ model provided only that the nucleon effective mass curve is given. We use a family of the possible nucleon effective mass curves that reproduce the empirical saturation point in the calculation of the nuclear binding energy curves in order to obtain density-dependent effective coupling constants. The resulting density-dependent coupling constants may be used to study a possible equation of state of nuclear system at high density or neutron matter. Within the constraints used in this paper to $M^*$ of nuclear matter at saturation point and zero density, neutron matter of large incompressibility is strongly bound at high density while soft neutron matter is weakly bound at low density. The study also exhibits the importance of surface vibration modes in the study of nuclear equation of state.
Investigation of the thermo-optic effect in doubly coupled photonic crystal split-beam nanocavities
Lin, Tong; Tao, Jifang; Chau, Fook Siong; Deng, Jie; Zhou, Guangya; Gu, Yuandong
2016-07-01
We design and experimentally demonstrate doubly coupled photonic crystal split-beam nanocavities. The thermal response of the coupled nanocavities is characterized by controlling the device temperature: the resonant wavelengths of the odd mode (1557.28 nm) and even mode (1567.18 nm) are both redshifted linearly from 17.4 °C to 46.5 °C. The tuning ratio of the two modes is measured to be 97.4%, implying that they respond almost the same to temperature changes. Therefore, changes of the wavelength difference between this pair of modes can be applied to effectively decouple the thermo-optic effect from the optomechanical effect without on-chip temperature self-referencing. Additionally, the topmost quality-factor approaches 28 300 throughout the thermal tuning. The proposed structure paves the way for studying purely optomechanical actuations.
Thermal Impedance Model of High Power IGBT Modules Considering Heat Coupling Effects
DEFF Research Database (Denmark)
Bahman, Amir Sajjad; Ma, Ke; Blaabjerg, Frede
2014-01-01
Thermal loading of Insulated Gate Bipolar Transistor (IGBT) modules is important for the reliability performance of power electronic systems, thus the thermal information of critical points inside module like junction temperature must be accurately modeled and predicted. Usually in the existing...... thermal models, only the self-heating effects of the chips are taken into account, while the thermal coupling effects among chips are less considered. This could result in inaccurate temperature estimation, especially in the high power IGBT modules where the chips are allocated closely to each other...... with large amount of heat generated. In this paper, both the self-heating and heat-coupling effects in the of IGBT module are investigated based on Finite Element Method (FEM) simulation, a new thermal impedance model is thereby proposed to better describe the temperature distribution inside IGBT modules...
An investigation of the role of spectroscopic factors in the breakup reaction of 11Be
Canbula, Bora; Canbula, Deniz; Babacan, Halil
2014-01-01
The experimental elastic cross section data of the projectile 11Be on target 12C at 49.3 MeV/nucleon energy is analysed. The calculations for the elastic scattering is performed by the phenomenological optical model. The different optical potentials to include breakup effects into the calculations, which are neutron+12C, neutron+10Be and 10Be+12C are described with the aid of the global potentials for neutron interactions and fitted to experimental data for the core and target interaction. Also, the first analysis of the optical model for 10Be on target 12C at 39.1 MeV is done for building the interaction potential of the core and the target for 11Be. For investigating the effects of the spectroscopic factor obtained from the direct capture process using the nuclear level density are compared with the previous cross section and spectroscopic factor results. Obtained results for the elastic cross section are reproduced the experimental data very well, and shows the requirement of including spectroscopic proper...
Dark matter coupling to electroweak gauge and Higgs bosons: An effective field theory approach
Chen, Jing-Yuan; Kolb, Edward W.; Wang, Lian-Tao
2013-12-01
If dark matter is a new species of particle produced in the early universe as a cold thermal relic (a weakly-interacting massive particle-WIMP), its present abundance, its scattering with matter in direct-detection experiments, its present-day annihilation signature in indirect-detection experiments, and its production and detection at colliders, depend crucially on the WIMP coupling to standard-model (SM) particles. It is usually assumed that the WIMP couples to the SM sector through its interactions with quarks and leptons. In this paper we explore the possibility that the WIMP coupling to the SM sector is via electroweak gauge and Higgs bosons. In the absence of an ultraviolet-complete particle-physics model, we employ effective field theory to describe the WIMP-SM coupling. We consider both scalars and Dirac fermions as possible dark-matter candidates. Starting with an exhaustive list of operators up to dimension 8, we present detailed calculation of dark-matter annihilations to all possible final states, including γγ, γZ, γh, ZZ, Zh, W+W-, hh, and ffbar, and demonstrate the correlations among them. We compute the mass scale of the effective field theory necessary to obtain the correct dark-matter mass density, and well as the resulting photon line signals.
Pan, Dan-Feng; Bi, Gui-Feng; Chen, Guang-Yi; Zhang, Hao; Liu, Jun-Ming; Wang, Guang-Hou; Wan, Jian-Guo
2016-03-08
Recently, ferroelectric perovskite oxides have drawn much attention due to potential applications in the field of solar energy conversion. However, the power conversion efficiency of ferroelectric photovoltaic effect currently reported is far below the expectable value. One of the crucial problems lies in the two back-to-back Schottky barriers, which are formed at the ferroelectric-electrode interfaces and blocking most of photo-generated carriers to reach the outside circuit. Herein, we develop a new approach to enhance the ferroelectric photovoltaic effect by introducing the polarization-dependent interfacial coupling effect. Through inserting a semiconductor ZnO layer with spontaneous polarization into the ferroelectric ITO/PZT/Au film, a p-n junction with strong polarization-dependent interfacial coupling effect is formed. The power conversion efficiency of the heterostructure is improved by nearly two orders of magnitude and the polarization modulation ratio is increased about four times. It is demonstrated that the polarization-dependent interfacial coupling effect can give rise to a great change in band structure of the heterostructure, not only producing an aligned internal electric field but also tuning both depletion layer width and potential barrier height at PZT-ZnO interface. This work provides an efficient way in developing highly efficient ferroelectric-based solar cells and novel optoelectronic memory devices.
Pan, Dan-Feng; Bi, Gui-Feng; Chen, Guang-Yi; Zhang, Hao; Liu, Jun-Ming; Wang, Guang-Hou; Wan, Jian-Guo
2016-01-01
Recently, ferroelectric perovskite oxides have drawn much attention due to potential applications in the field of solar energy conversion. However, the power conversion efficiency of ferroelectric photovoltaic effect currently reported is far below the expectable value. One of the crucial problems lies in the two back-to-back Schottky barriers, which are formed at the ferroelectric-electrode interfaces and blocking most of photo-generated carriers to reach the outside circuit. Herein, we develop a new approach to enhance the ferroelectric photovoltaic effect by introducing the polarization-dependent interfacial coupling effect. Through inserting a semiconductor ZnO layer with spontaneous polarization into the ferroelectric ITO/PZT/Au film, a p-n junction with strong polarization-dependent interfacial coupling effect is formed. The power conversion efficiency of the heterostructure is improved by nearly two orders of magnitude and the polarization modulation ratio is increased about four times. It is demonstrated that the polarization-dependent interfacial coupling effect can give rise to a great change in band structure of the heterostructure, not only producing an aligned internal electric field but also tuning both depletion layer width and potential barrier height at PZT-ZnO interface. This work provides an efficient way in developing highly efficient ferroelectric-based solar cells and novel optoelectronic memory devices. PMID:26954833
Pan, Dan-Feng; Bi, Gui-Feng; Chen, Guang-Yi; Zhang, Hao; Liu, Jun-Ming; Wang, Guang-Hou; Wan, Jian-Guo
2016-03-01
Recently, ferroelectric perovskite oxides have drawn much attention due to potential applications in the field of solar energy conversion. However, the power conversion efficiency of ferroelectric photovoltaic effect currently reported is far below the expectable value. One of the crucial problems lies in the two back-to-back Schottky barriers, which are formed at the ferroelectric-electrode interfaces and blocking most of photo-generated carriers to reach the outside circuit. Herein, we develop a new approach to enhance the ferroelectric photovoltaic effect by introducing the polarization-dependent interfacial coupling effect. Through inserting a semiconductor ZnO layer with spontaneous polarization into the ferroelectric ITO/PZT/Au film, a p-n junction with strong polarization-dependent interfacial coupling effect is formed. The power conversion efficiency of the heterostructure is improved by nearly two orders of magnitude and the polarization modulation ratio is increased about four times. It is demonstrated that the polarization-dependent interfacial coupling effect can give rise to a great change in band structure of the heterostructure, not only producing an aligned internal electric field but also tuning both depletion layer width and potential barrier height at PZT-ZnO interface. This work provides an efficient way in developing highly efficient ferroelectric-based solar cells and novel optoelectronic memory devices.
Coupling and corona effects research plan for transmission lines. Final report
Energy Technology Data Exchange (ETDEWEB)
Bridges, J E; Formanek, V C
1976-06-01
Concern has arisen over the possible effects of electric and magnetic fields produced by EHV-UHV transmission lines. Past and ongoing research concerning the electric and magnetic field effects from EHV-UHV transmission lines was reviewed as it pertains to the following areas: (1) electromagnetic interference, (2) acoustic noise, (3) generation of gaseous effluents, and (4) safety considerations of induced voltages and currents. The intent of this review was to identify the short and long range research projects required to address these areas. The research plan identifies and gives priority to twenty programs in corona and coupling effects. In the case of the corona effects, a number of programs were recommended for acoustic noise and electromagnetic interference to delineate improved power line design criteria in terms of social, meteorological, geographical and cost constraints. Only one project is recommended in the case of ozone generation, because the results of comprehensive analyses, laboratory studies and field measurements have demonstrated that power lines do not contribute significant quantities of ozone. In the case of the coupling effects, a number of programs are recommended for HVAC transmission lines to improve the theoretically developed design guidelines by considering practical constraints. For HVDC transmission lines, programs are suggested to engender a better theoretical understanding and practical measurements capability for the coupling mechanisms of the dc electric and magnetic field with nearby objects. The interrelationship of the programs and their role in a long-term research plan is also discussed.
The Effect of Teaching Communicative Patterns of Pluralistic Family on Couples Happiness
Directory of Open Access Journals (Sweden)
H Molavi
2010-07-01
Full Text Available Introduction & Objective: One of the basic elements declared in positive psychology is the concept of happiness. Researches have shown that without concerning how achieved, happiness can enhance our health. People who are happy feel more secure, decide easier, and are more satisfied of the people who live with. The aim of the present study was to measure the efficiency of teaching communicative pattern of pluralistic family on the happiness of couples. Materials & Method:This experimental study was designed to have a pre-test and post test and also a control group. Subjects of this study were comprised of consultation centers clients in Shiraz and was based on random sampling. Forty couples were selected according to the revised version of family communication patterns of Koerner and Fitzpatrick. Two dimensions, namely laisseze fair and protective family patterns, were taken into account through the process of selection . Oxford Happiness Invintory was administered to 40 couples and they were randomly divided into a control and an experimental group. Ten training sessions, 90- minute each, were held for experimental group exposed to pluralistic communication patterns. Three Couples declined and finally 34 couples were analyzed.The test was run for both groups and data was analyzed with covariance analysis method using SPSSI5. Results:The results of the present study revealed that with regard to happiness, there is a meaningful difference in both groups (p<0.005. The difference also existed between the pretest and post test scores of happiness test in both groups (p<0.0001. However, communication patterns and interaction between both groups did not reach a meaningful level. Conclusion: Based on the finding, it can be concluded that listening to and speaking with each other play a key role in happiness, therefore pluralistic communication methods based on high levels of listing speaking interactions can be effective happiness of couples.
Numerical and experimental study of liquid breakup process in solid rocket motor nozzle
Yen, Yi-Hsin
Rocket propulsion is an important travel method for space exploration and national defense, rockets needs to be able to withstand wide range of operation environment and also stable and precise enough to carry sophisticated payload into orbit, those engineering requirement makes rocket becomes one of the state of the art industry. The rocket family have been classified into two major group of liquid and solid rocket based on the fuel phase of liquid or solid state. The solid rocket has the advantages of simple working mechanism, less maintenance and preparing procedure and higher storage safety, those characters of solid rocket make it becomes popular in aerospace industry. Aluminum based propellant is widely used in solid rocket motor (SRM) industry due to its avalibility, combusion performance and economical fuel option, however after aluminum react with oxidant of amonimum perchrate (AP), it will generate liquid phase alumina (Al2O3) as product in high temperature (2,700˜3,000 K) combustion chamber enviornment. The liquid phase alumina particles aggromorate inside combustion chamber into larger particle which becomes major erosion calprit on inner nozzle wall while alumina aggromorates impinge on the nozzle wall surface. The erosion mechanism result nozzle throat material removal, increase the performance optimized throat diameter and reduce nozzle exit to throat area ratio which leads to the reduction of exhaust gas velocity, Mach number and lower the propulsion thrust force. The approach to avoid particle erosion phenomenon taking place in SRM's nozzle is to reduce the alumina particle size inside combustion chamber which could be done by further breakup of the alumina droplet size in SRM's combustion chamber. The study of liquid breakup mechanism is an important means to smaller combustion chamber alumina droplet size and mitigate the erosion tack place on rocket nozzle region. In this study, a straight two phase air-water flow channel experiment is set up
Energy Technology Data Exchange (ETDEWEB)
Soudackov, Alexander V.; Hammes-Schiffer, Sharon [Department of Chemistry, University of Illinois at Urbana-Champaign, 600 South Mathews Ave., Urbana, Illinois 61801 (United States)
2015-11-21
Rate constant expressions for vibronically nonadiabatic proton transfer and proton-coupled electron transfer reactions are presented and analyzed. The regimes covered include electronically adiabatic and nonadiabatic reactions, as well as high-frequency and low-frequency proton donor-acceptor vibrational modes. These rate constants differ from previous rate constants derived with the cumulant expansion approach in that the logarithmic expansion of the vibronic coupling in terms of the proton donor-acceptor distance includes a quadratic as well as a linear term. The analysis illustrates that inclusion of this quadratic term in the framework of the cumulant expansion framework may significantly impact the rate constants at high temperatures for proton transfer interfaces with soft proton donor-acceptor modes that are associated with small force constants and weak hydrogen bonds. The effects of the quadratic term may also become significant in these regimes when using the vibronic coupling expansion in conjunction with a thermal averaging procedure for calculating the rate constant. In this case, however, the expansion of the coupling can be avoided entirely by calculating the couplings explicitly for the range of proton donor-acceptor distances sampled. The effects of the quadratic term for weak hydrogen-bonding systems are less significant for more physically realistic models that prevent the sampling of unphysical short proton donor-acceptor distances. Additionally, the rigorous relation between the cumulant expansion and thermal averaging approaches is clarified. In particular, the cumulant expansion rate constant includes effects from dynamical interference between the proton donor-acceptor and solvent motions and becomes equivalent to the thermally averaged rate constant when these dynamical effects are neglected. This analysis identifies the regimes in which each rate constant expression is valid and thus will be important for future applications to proton
International Nuclear Information System (INIS)
The current doctoral research is focused on the development and validation of a coupled computational tool, to combine the advantages of computational fluid dynamics (CFD) in analyzing complex flow fields and of state-of-the-art system codes employed for nuclear power plant (NPP) simulations. Such a tool can considerably enhance the analysis of NPP transient behavior, e.g. in the case of pressurized water reactor (PWR) accident scenarios such as Main Steam Line Break (MSLB) and boron dilution, in which strong coolant flow asymmetries and multi-dimensional mixing effects strongly influence the reactivity of the reactor core, as described in Chap. 1. To start with, a literature review on code coupling is presented in Chap. 2, together with the corresponding ongoing projects in the international community. Special reference is made to the framework in which this research has been carried out, i.e. the Paul Scherrer Institute's (PSI) project STARS (Steady-state and Transient Analysis Research for the Swiss reactors). In particular, the codes chosen for the coupling, i.e. the CFD code ANSYS CFX V11.0 and the system code US-NRC TRACE V5.0, are part of the STARS codes system. Their main features are also described in Chap. 2. The development of the coupled tool, named CFX/TRACE from the names of the two constitutive codes, has proven to be a complex and broad-based task, and therefore constraints had to be put on the target requirements, while keeping in mind a certain modularity to allow future extensions to be made with minimal efforts. After careful consideration, the coupling was defined to be on-line, parallel and with non-overlapping domains connected by an interface, which was developed through the Parallel Virtual Machines (PVM) software, as described in Chap. 3. Moreover, two numerical coupling schemes were implemented and tested: a sequential explicit scheme and a sequential semi-implicit scheme. Finally, it was decided that the coupling would be single
Far-field breakup of spiral waves in the plankton ecological systems
Liu, Quan-Xing
2007-01-01
For oscillatory conditions, breakup of the spiral waves far away from the spiral core (as so-called "far-field breakup") was reported in a simple activator-inhibitor model by Markus B\\"{a}r, Michal Or-Guil and Lutz Brusch [Phys. Rev. Lett. \\textbf{82}, 1160 (1999) and New J. Phys. \\textbf{6}, 5 (2004)], which is in the chemical reaction-diffusion system. In present letter, the scenario in the plankton ecological system is reported. The spatial plankton model is studied numerically by computer and we find that the far-field breakup also exists in the oceanic ecological systems over a range of diffusion coefficients of phytoplankton and zooplankton. The far-field breakup leading to the spatial chaos patterns can be verified in field observation and is useful to understand the population dynamics of oceanic ecological systems. It also indicates that the far-field breakup may be a common phenomenon in the world. Finally, we give some illumination from the ecological meaning.
Nuclear-breakup mechanisms in the interaction of relativistic projectiles with heavy targets
International Nuclear Information System (INIS)
The breakup of a Au nucleus under bombardment with relativistic p, α, and 20Ne has been investigated in an extensive, multi-detector study. The present discussion addresses some of the many aspects of the experimental results. A broad distribution of coincident fragment masses is observed, with the total fragment kinetic energy being higher than expected for a fission mechanism for total fragment mass less than or equal to 120. The formation of light fragments is shown to be inconsistent with a binary breakup mechanism, and a multi-fragment target breakup is suggested. In general, the results indicate a broad spectrum of violence in the collisions, from gentle, leading to the production of heavy spallation products and fission, to essentially explosive, leading to multi-fragment breakup into light mas products. These aspects of the reactions represent a late-stage breakup of the target residues and are positively correlated with the violence of the initial fast stage of the collision as measured by the charged particle multiplicity
Three-cluster breakup in deuteron-deuteron collisions: single-scattering approximation
Deltuva, A
2016-01-01
We present results for the three-cluster breakup in deuteron-deuteron collisions at 130 and 270 MeV deuteron beam energy. The breakup amplitude is calculated using the first term in the Neumann series expansion of the corresponding exact four-nucleon equations. In analogy with nucleon-deuteron breakup where an equivalent approximation is compared with exact calculations, we expect this single-scattering approximation to provide a rough estimation of three-body breakup observables in quasifree configurations. We predict the nucleon-deuteron and deuteron-deuteron three-cluster breakup cross sections to be of a comparable size and thereby question the reliability of the recent experimental data [A. Ramazani-Moghaddam-Arani, Ph.D. thesis, University of Groningen, 2009; A. Ramazani-Moghaddam-Arani et al., EPJ Web of Conferences 3, 04012 (2010)] that is smaller by about three orders of magnitude. We also show that an equivalent single-scattering approximation provides a reasonable description of deuteron-deuteron e...
Neutron Induced D Breakup in Inertial Confinement Fusion at the Omega Laser Facility
Forrest, C. J.; Glebov, V. Yu.; Knauer, J. P.; Radha, P. B.; Regan, S. P.; Sangster, T. C.; Stoeckl, C.; Schroder, W. U.; Frenje, J. A.; Gatu Johnson, M.
2015-11-01
High-resolution neutron spectroscopy is used to study the deuteron breakup reaction D(n,n ') np in the thermonuclear environment created in inertial confinement fusion experiments at the Omega Laser Facility. Neutrons with an energy of 14.1 MeV generated in the primary D-T fusion reactions scatter elastically and inelastically off the dense (cryogenic) D-T fuel assembly surrounding the central hot spot at peak fuel compression. These neutrons also induce a breakup of the fuel deuterons. The corresponding breakup cross section is measured relative to elastic n -D and n -T scattering, i.e., simultaneously in the same environment. Apart from astrophysical and technological interest, the neutron-induced deuteron breakup reaction is of interest to the physics of nucleon -nucleon forces. For example, theoretical calculations predict a noticeable influence of nucleonic three-body forces on the magnitude of the breakup cross section. Preliminary results from measurements of the neutron contribution in the 2- to 6-MeV range show reasonable agreement with the published ENDL 2008.2 semi-empirical cross-section. This material is based upon work supported by the Department of Energy National Nuclear Security Administration under Award Number DE-NA0001944.
Mechanism of Water Droplet Breakup Near the Leading Edge of an Airfoil
Vargas, Mario; Sor, Suthyvann; Magarino, Adelaida, Garcia
2012-01-01
This work presents results of an experimental study on droplet deformation and breakup near the leading edge of an airfoil. The experiment was conducted in the rotating rig test cell at the Instituto Nacional de Tecnica Aeroespacial (INTA) in Madrid, Spain. The airfoil model was placed at the end of the rotating arm and a monosize droplet generator produced droplets that fell from above, perpendicular to the path of the airfoil. The interaction between the droplets and the airfoil was captured with high speed imaging and allowed observation of droplet deformation and breakup as the droplet approached the airfoil near the stagnation line. Image processing software was used to measure the position of the droplet centroid, equivalent diameter, perimeter, area, and the major and minor axes of an ellipse superimposed over the deforming droplet. The horizontal and vertical displacement of each droplet against time was also measured, and the velocity, acceleration, Weber number, Bond number, Reynolds number, and the drag coefficients were calculated along the path of the droplet to the beginning of breakup. Droplet deformation is defined and studied against main parameters. The high speed imaging allowed observation of the actual mechanism of breakup and identification of the sequence of configurations from the initiation of the breakup to the disintegration of the droplet. Results and comparisons are presented for droplets of diameters in the range of 500 to 1800 microns, and airfoil velocities of 70 and 90 m/sec.
Assessment of the Breakup of the Antarctic Polar Vortex in Two New Chemistry-Climate Models
Hurwitz, M. M.; Newman, P. A.; Oman, L. D.; Li, F.; Morgenstern, O.; Braesicke, P.; Pyle, J. A.
2010-01-01
Successful simulation of the breakup of the Antarctic polar vortex depends on the representation of tropospheric stationary waves at Southern Hemisphere middle latitudes. This paper assesses the vortex breakup in two new chemistry-climate models (CCMs). The stratospheric version of the UK Chemistry and Aerosols model is able to reproduce the observed timing of the vortex breakup. Version 2 of the Goddard Earth Observing System (GEOS V2) model is typical of CCMs in that the Antarctic polar vortex breaks up too late; at 10 hPa, the mean transition to easterlies at 60 S is delayed by 12-13 days as compared with the ERA-40 and National Centers for Environmental Prediction reanalyses. The two models' skill in simulating planetary wave driving during the October-November period accounts for differences in their simulation of the vortex breakup, with GEOS V2 unable to simulate the magnitude and tilt of geopotential height anomalies in the troposphere and thus underestimating the wave driving. In the GEOS V2 CCM the delayed breakup of the Antarctic vortex biases polar temperatures and trace gas distributions in the upper stratosphere in November and December.
Development of the VESUVIUS module. Molten jet breakup modeling and model verification
Energy Technology Data Exchange (ETDEWEB)
Vierow, K. [Nuclear Power Engineering Corp., Tokyo (Japan); Nagano, Katsuhiro; Araki, Kazuhiro
1998-01-01
With the in-vessel vapor explosion issue ({alpha}-mode failure) now considered to pose an acceptably small risk to the safety of a light water reactor, ex-vessel vapor explosions are being given considerable attention. Attempts are being made to analytically model breakup of continuous-phase jets, however uncertainty exists regarding the basic phenomena. In addition, the conditions upon reactor vessel failure, which determine the starting point of the ex-vessel vapor explosion process, are difficult to quantify. Herein, molten jet ejection from the reactor pressure vessel is characterized. Next, the expected mode of jet breakup is determined and the current state of analytical modeling is reviewed. A jet breakup model for ex-vessel scenarios, with the primary breakup mechanism being the Kelvin-Helmholtz instability, is described. The model has been incorporated into the VESUVIUS module and comparisons of VESUVIUS calculations against FARO L-06 experimental data show differences, particularly in the pressure curve and amount of jet breakup. The need for additional development to resolve these differences is discussed. (author)
Capillary thinning and breakup of saliva threads and rheological aging of mucin solutions
Wagner, Caroline; Bourouiba, Lydia; McKinley, Gareth
2014-11-01
The elasticity of saliva, which is essential for many of its primary functions such as lubrication, arises largely as a result of the presence of MUC5B mucins. These are large glycoproteins composed of numerous repeated polymeric subunits forming a weakly crosslinked network. It has been noted for nearly a century that once removed from the mouth, saliva quickly loses its elasticity, which can be quantified by a decrease in its capillary breakup time. We model saliva as a dilute finitely extensible nonlinear elastic (FENE-P) fluid with polymer chains composed of dispersed Hookean dumbbells of maximum extensibility b related to the number of MUC5B subunits. We show that under conditions of simple elongational flow, an analytic prediction of the time evolution of the radius and the filament breakup time can be derived. Furthermore, our model shows that decreasing the maximum extensibility b leads to a decrease in the breakup time, which suggests that the aging process of saliva outside the mouth involves a shortening of the MUC5B mucin chains into smaller groupings. Finally, we compare the analytic breakup times from the model with experimental results obtained using a capillary breakup extensional rheometer and human whole saliva.
Three-cluster breakup in deuteron-deuteron collisions: Single-scattering approximation
Deltuva, A.; Fonseca, A. C.
2016-04-01
We present results for the three-cluster breakup in deuteron-deuteron collisions at 130 and 270 MeV deuteron beam energy. The breakup amplitude is calculated using the first term in the Neumann series expansion of the corresponding exact four-nucleon equations. In analogy with nucleon-deuteron breakup where an equivalent approximation is compared with exact calculations, we expect this single-scattering approximation to provide a rough estimation of three-body breakup observables in quasifree configurations. We predict the nucleon-deuteron and deuteron-deuteron three-cluster breakup cross sections to be of a comparable size and thereby question the reliability of the recent experimental data [A. Ramazani-Moghaddam-Arani, Ph.D. thesis, University of Groningen, 2009; A. Ramazani-Moghaddam-Arani et al., EPJ Web Conf. 3, 04012 (2010), 10.1051/epjconf/20100304012], which are smaller by about three orders of magnitude. We also show that an equivalent single-scattering approximation provides a reasonable description of deuteron-deuteron elastic scattering at forward-scattering angles.
To investigate the coupled effects of solution chemistry and vadose zone processes on the mobility of quantum dot (QD) nanoparticles, laboratory scale transport experiments were performed. The complex coupled effects of ionic strength, size of QD aggregates, surface tension, contact angle, infiltrat...
Gauge Coupling Field, Currents, Anomalies and N=1 Super-Yang-Mills Effective Actions
Ambrosetti, Nicola; Derendinger, Jean-Pierre; Hartog, Jelle
2016-01-01
Working with a gauge coupling field in a linear superfield, we construct effective Lagrangians for N=1 super-Yang-Mills theory fully compatible with the expected all-order behaviour or physical quantities. Using the one-loop dependence on its ultraviolet cutoff and anomaly matching or cancellation of R and dilatation anomalies, we obtain the Wilsonian effective Lagrangian. With similar anomaly matching or cancellation methods, we derive the effective action for gaugino condensates, as a function of the real coupling field. Both effective actions lead to a derivation of the NSVZ beta function from algebraic arguments only. The extension of results to N=2 theories or to matter systems is briefly considered. The main tool for the discussion of anomalies is a generic supercurrent structure with 16_B+16_F operators (the S multiplet), which we derive using superspace identities and field equations for a fully general gauge theory Lagrangian with the linear gauge coupling superfield, and with various U(1)_R currents...
Rashba spin–orbit coupling effects on a current-induced domain wall motion
International Nuclear Information System (INIS)
A current-induced domain wall motion in magnetic nanowires with a strong structural inversion asymmetry [I.M. Miron, T. Moore, H. Szambolics, L.D. Buda-Prejbeanu, S. Auffret, B. Rodmacq, S. Pizzini, J. Vogel, M. Bonfim, A. Schuhl, G. Gaudin, Nat. Mat. 10 (2011) 419] seems to have novel features such as the domain wall motion along the current direction or the delay of the onset of the Walker breakdown. In such a highly asymmetric system, the Rashba spin–orbit coupling (RSOC) may affect a domain wall motion. We studied theoretically the RSOC effects on a domain wall motion and found that the RSOC, indeed, can induce the domain wall motion along the current direction in certain situations. It also delays the Walker breakdown and for a strong RSOC, the Walker breakdown does not occur at all. The RSOC effects are sensitive to the magnetic anisotropy of nanowires and also to the ratio between the Gilbert damping parameter α and the non-adiabaticity parameter β. - Highlights: ► Effects of Rashba spin–orbit coupling on a domain wall motion is calculated. ► The effects depend highly on the anisotropy of a magnetic system. ► It modifies the wall velocity for the system with a perpendicular magnetic anisotropy. ► The modified velocity can be along the current direction in certain situations. ► Rashba spin–orbit coupling also hinders the onset of the Walker breakdown.
The effective lifetime and temperature coefficient in a coupled fast-thermal reactor
International Nuclear Information System (INIS)
The theory of coupled systems was extensively developed by Avery and co-workers at the Argonne National Laboratory. One of the main points of interest in a coupled system is the larger effective lifetime of neutrons. The effect of the thermal component acts as a sort of neutron-delayer. As in the theory of delayed neutrons the delaying effect disappears if the reactivity worth is high enough to make the fast component critical by itself. In the study a coupled reactor is considered where the fast component suffers a sudden reactivity step α0. Because of the increasing power-level the temperature rises and two temperature coefficients start to work: the temperature coefficient of the fast component and the temperature coefficient of the thermal component. The problem is considered with one group of delayed neutrons (in the ordinary meaning). A formalism is given to express the effective lifetime and temperature coefficient during the different stages of the excursion. Excursions for different α0 are given so that the limit of fast-reactor kinetics is reached. (author)
Physics-Based Modeling of Meteor Entry and Breakup
Prabhu, Dinesh K.; Agrawal, Parul; Allen, Gary A., Jr.; Bauschlicher, Charles W., Jr.; Brandis, Aaron M.; Chen, Yih-Kang; Jaffe, Richard L.; Palmer, Grant E.; Saunders, David A.; Stern, Eric C.; Tauber, Michael E.; Venkatapathy, Ethiraj
2015-01-01
A new research effort at NASA Ames Research Center has been initiated in Planetary Defense, which integrates the disciplines of planetary science, atmospheric entry physics, and physics-based risk assessment. This paper describes work within the new program and is focused on meteor entry and breakup.Over the last six decades significant effort was expended in the US and in Europe to understand meteor entry including ablation, fragmentation and airburst (if any) for various types of meteors ranging from stony to iron spectral types. These efforts have produced primarily empirical mathematical models based on observations. Weaknesses of these models, apart from their empiricism, are reliance on idealized shapes (spheres, cylinders, etc.) and simplified models for thermal response of meteoritic materials to aerodynamic and radiative heating. Furthermore, the fragmentation and energy release of meteors (airburst) is poorly understood.On the other hand, flight of human-made atmospheric entry capsules is well understood. The capsules and their requisite heatshields are designed and margined to survive entry. However, the highest speed Earth entry for capsules is 13 kms (Stardust). Furthermore, Earth entry capsules have never exceeded diameters of 5 m, nor have their peak aerothermal environments exceeded 0.3 atm and 1 kW/sq cm. The aims of the current work are: (i) to define the aerothermal environments for objects with entry velocities from 13 to 20 kms; (ii) to explore various hypotheses of fragmentation and airburst of stony meteors in the near term; (iii) to explore the possibility of performing relevant ground-based tests to verify candidate hypotheses; and (iv) to quantify the energy released in airbursts. The results of the new simulations will be used to anchor said risk assessment analyses. With these aims in mind, state-of-the-art entry capsule design tools are being extended for meteor entries. We describe: (i) applications of current simulation tools to
Effects of Explicit Convection on Global Land-atmosphere Coupling in the Superparameterized CAM
Sun, J.; Pritchard, M. S.
2015-12-01
Many global climate models are prone to producing land-atmosphere coupling dynamics that are too strong and simplistic. Cumulus and convection parameterizations are natural culprits but the effect of bypassing them with explicitly resolved convection on global land-atmosphere coupling dynamics has not been explored systematically. We apply a suite of modern land-atmosphere coupling diagnostics to isolate the effect of cloud superparameterization (SP) in the Community Atmosphere Model v3.5, focusing on both the land segment (i.e., soil moisture and evapotranspiration relationship) and atmospheric segment (i.e., evapotranspiration and precipitation relationship) in the water pathway of the land-atmosphere feedback loop. Comparing SPCAM3.5 and conventional CAM3.5 in daily timescale, our results show that the Super-Parameterized model reduces the coupling strength in the Central Great Plain in American, and reverses the terrestrial segment coupling sign (from negative to positive) over India. Which are consistent with previous studies and are favorable improvements on the known issues reported in literatures. Analysis of the triggering feedback strength (TFS) and amount feedback strength (AFS) shows that SPCAM3.5 favorably reproduces the patterns of these indices over North America, with probability of afternoon precipitation enhanced by high evaporative fraction along the eastern United States and Mexico, while conventional CAM3.5 does not capture this signal. The links in the soil moisture-precipitation feedback loop are further explored through applying the mixing diagram approach to the diurnal cycles of the land surface and planetary boundary layer variables.
Thermoelectric effect in the Kondo dot side-coupled to a Majorana mode
Khim, Heunghwan; López, Rosa; Lim, Jong Soo; Lee, Minchul
2015-06-01
We investigate the linear thermoelectric response of an interacting quantum dot side-coupled by one of two Majorana modes hosted by a topological superconducting wire. We employ the numerical renormalization group technique to obtain the thermoelectrical conductance L in the Kondo regime while the background temperature T, the Majorana-dot coupling Γm, and the overlap ɛm between the two Majorana modes are tuned. We distinguish two transport regimes in which L displays different features: the weak- (ΓmTK) regimes, where TK is the Kondo temperature. For an infinitely long nanowire where the Majorana modes do not overlap (ɛm = 0), the thermoelectrical conductance in the weak-coupling regime exhibits a peak at T ~ ΓmFano resonance between the asymmetric Kondo resonance and the zero-energy Majorana bound state. In the strong-coupling regime, on the other hand, the Kondo-induced peak in L is affected by the induced Zeeman splitting in the dot. For finite but small overlap (0 interference between the two Majorana modes restores the Kondo effect in a smaller energy scale Γ'm and gives rise to an additional peak in Γ ~ Γ'm, whose sign is opposite to that at T ~ Γm. In the strong-coupling regime this additional peak can cause a non-monotonic behavior of L with respect to the dot gate. Finally, in order to identify the fingerprint of Majorana physics, we compare the Majorana case with its counterpart in which the Majorana bound states are replaced by a (spin-polarized) ordinary bound state and find that the thermoelectric features for finite ɛm are the genuine effect of the Majorana physics.
Simulating Chiral Magnetic and Separation Effects with Spin-Orbit Coupled Atomic Gases
Xu-Guang Huang
2016-01-01
The chiral magnetic and chiral separation effects---quantum-anomaly-induced electric current and chiral current along an external magnetic field in parity-odd quark-gluon plasma---have received intense studies in the community of heavy-ion collision physics. We show that analogous effects occur in rotating trapped Fermi gases with Weyl-Zeeman spin-orbit coupling where the rotation plays the role of an external magnetic field. These effects can induce a mass quadrupole in the atomic cloud alon...
Operating conditions effect over the coupling strength for urban aerial ropeways
Directory of Open Access Journals (Sweden)
Ronald M. MARTINOD
2014-09-01
Full Text Available The present work is aimed to assess the operating conditions effect for urban aerial ropeways with a commercial usage, based on measurements obtained from an arrangement of sensors that record the coupling assembly behavior between the detachable gondola pod and the track rope. The work pays particular attention to the effect caused by external conditions due to the wind loads joined up with other parasite external effects, through the measurement of the engage strains. The cableway gondola continuous cycle has mono-cable of simple ring type.
Anomalous coupling, top-mass and parton-shower effects in W + W - production
Bellm, J.; Gieseke, S.; Greiner, N.; Heinrich, G.; Plätzer, S.; Reuschle, C.; von Soden-Fraunhofen, J. F.
2016-05-01
We calculate the process ppto {W}+{W}-to {e}+{ν}_e{μ}-{overline{ν}}_{μ } at NLO QCD, including also effective field theory (EFT) operators mediating the ggW + W - interaction, which first occur at dimension eight. We further combine the NLO and EFT matrix elements produced by G oS am with the H erwig7/M atchbox framework, which offers the possibility to study the impact of a parton shower. We assess the effects of the anomalous couplings by comparing them to top-mass effects as well as uncertainties related to variations of the renormalisation, factorisation and hard shower scales.
Core Polarization and Tensor Coupling Effects on Magnetic Moments of Hypernuclei
Institute of Scientific and Technical Information of China (English)
YAO Jiang-Ming; L(U) Hong-Feng; Hillhouse Greg; MENG Jie
2008-01-01
Effects of core polarization and tensor coupling on the magnetic moments in 13Λ C,17Λ O,and 41Λ Ca Λ-hypernuclei are studied by employing the Dirac equation with scalar,vector and tensor potentials.It is found that the effect of core polarization on the magnetic moments is suppressed by Λ tensor coupling.The Λ tensor potential reduces the spin-orbit splitting of PΛ states considerably.However,almost the same magnetic moments are obtained using the hyperon wavefunction obtained via the Dirac equation either with or without the Λ tensor potential in the electromagnetic current vertex.The deviations of magnetic moments for pΛ states from the Schmidt values are found to increase with nuclear mass number.
Mode-coupling and nonlinear Landau damping effects in auroral Farley-Buneman turbulence
Hamza, Abdelaziz M
2015-01-01
The fundamental problem of Farley-Buneman turbulence in the auroral $E$-region has been discussed and debated extensively in the past two decades. In the present paper we intend to clarify the different steps that the auroral $E$-region plasma has to undergo before reaching a steady state. The mode-coupling calculation, for Farley-Buneman turbulence, is developed in order to place it in perspective and to estimate its magnitude relative to the anomalous effects which arise through the nonlinear wave-particle interaction. This nonlinear effect, known as nonlinear ``Landau damping'' is due to the coupling of waves which produces other waves which in turn lose energy to the bulk of the particles by Landau damping. This leads to a decay of the wave energy and consequently a heating of the plasma. An equation governing the evolution of the field spectrum is derived and a physical interpration for each of its terms is provided.
Quantum well effect based on hybridization bandgap in deep subwavelength coupled meta-atoms
Energy Technology Data Exchange (ETDEWEB)
Chen, Yongqiang; Li, Yunhui, E-mail: liyunhui@tongji.edu.cn; Wu, Qian; Jiang, Haitao; Zhang, Yewen; Chen, Hong
2015-09-01
In this paper, quantum well (QW) effect in a hybridization bandgap (HBG) structure via hiring deep subwavelength coupled meta-atoms is investigated. Subwavelength zero-index-metamaterial-based resonators acting as meta-atoms are side-coupled to a microstrip, forming the HBG structure. Both numerical and microwave experimental results confirm that, through properly hiring another set of meta-atoms, band mismatch between two HBGs can be introduced resulting in the HBG QW effect. Compared with the conventional QW structure based on Bragg interferences in photonic crystal, the device length of the proposed HBG QW structure can be reduced to only 1/4, demonstrating well the deep subwavelength property. Therefore, the above features make our design of HBG QW structures suitable to be utilized as multi-channel filters or multiplexers in microwave and optical communication system.
Effectiveness of Positive Couple Therapy on Life Satisfaction of Mothers of
Directory of Open Access Journals (Sweden)
Mustafa Bolghanabadi
2014-05-01
Full Text Available Background: Satisfaction with life has a vital role in human’s well being and health. The aim of this study was investigate to effectiveness of the positive couple therapy on improving satisfaction with life of mothers of children with special needs. Materials and methods: The research method was semi-experimental with pretest/posttest/follow-up design with control group. Among mothers with special needs children of Mashhad were recruited 20 subjects through purposely method and were assigned in experimental and control groups randomly (10 subjects in each group. For gathering data, satisfaction with life questionnaire was used. Results: Findings showed that life satisfaction of mothers with special needs children who received intervention had increased. Conclusion: Couple therapy with positive approach has been effective on increasing the life satisfaction of mothers with special needs children of Mashhad.
Spin-Orbit Coupling Effects in AumPtn Clusters (m + n = 4).
Moreno, Norberto; Ferraro, Franklin; Flórez, Elizabeth; Hadad, C Z; Restrepo, Albeiro
2016-03-17
A study of AumPtn(m + n = 4) clusters with and without spin-orbit (SO) coupling using scalar relativistic (SR) and two component methods with the ZORA Hamiltonian was carried out. We employed the PW91 functional in conjunction with the all-electron TZ2P basis set. This paper offers a detailed analysis of the SO effects on the cluster geometries, on the LUMO-HOMO gap, on the charge distribution, and on the relative energies for each relativistic method. In general, SO coupling led to an energetic rearrangement of the species, to changes in geometries and structural preferences, to changes in the structural identity of the global minimum for the Au3Pt, AuPt3 and Pt4 cases, and to a reduction of relative energies among the clusters, an effect that appears stronger as the amount of Pt increases.
Institute of Scientific and Technical Information of China (English)
张志荣; 冉景煜
2012-01-01
应用湍流模型和流体体积模型方法对液滴在低温低速烟气中的破碎特性进行数值研究,重点分析液滴韦伯数和雷诺数对液滴破碎方式的影响,以及烟气密度、流速、液滴速度和粒径等对液滴破碎时间的影响。计算结果表明：对于文中研究的低温低速气体环境及液滴,主要存在液滴发生袋式破碎及没有发生破碎两种形式,临界韦伯数为10.6。韦伯数是液滴破碎的尺度,雷诺数在液滴破碎中不是关键因素。对于文中的气体环境和液滴,综合影响下液滴无量纲破碎时间为常数1,独立于液滴粒径。在文中低温低速气体环境中,将液滴粒径控制在0.3~0.4 mm有助于缩短液滴的完全蒸发时间,提高液滴群蒸发效率。%In this paper,the volume of fluid（VOF）method and a turbulent model were employed to study the character of the drop breakup in the low temperature and low velocity flue gas numerically.The effects of We and Re number on breakup mode were analyzed.The effects of flue gas density and velocity,droplet velocity and diameter on breakup time were also analyzed.The results show that there are two kinds of breakup manner,that are the big breakup process and no breakup process with regard to the gas and droplet studied.The critical Weber number equals to 10.6.In the atmosphere considered,the Weber number is a rule of the droplet breakup,and the Re number is not a critical factor in the process of the liquid drop breakup.Considering the integrated factors,the normalized breakup time of droplet is independent of the droplet diameter,revealing constant 1,within the range of the gas and the droplet studied.In the low temperature and low velocity gas considered,it can conduce to the shorter life time of drop during the evaporation that controls the drop diameter within the range of 0.3~0.4 mm,therefore improving the evaporation efficiency of the drop group.
Sensitivity of N/Z ratio in projectile break-up of isobaric systems
Directory of Open Access Journals (Sweden)
De Filippo E.
2016-01-01
Full Text Available The binary break-up of projectile-like fragments in non central heavy-ion collisions follows different decay patterns, from equilibrated emission towards dynamical (prompt fission. Recently, comparing two systems with different N/Z in the entrance channel, it has been shown that the dynamical emission cross-section is enhanced for the most neutron rich system while the statistical emission cross-section is independent from the isotopic composition. In order to understand this dependence and disentangle it from the initial size of the nuclei, we have studied the two isobaric systems 124Xe+64 Zn and 124Xe+64 Ni at 35 A MeV (InKiIsSy experiment, in comparison with the previous studied reactions (124Sn +64 Ni and 112Sn +58 Ni at the same bombarding energy. We present the first results evidencing a striking similar effect in the dynamical decay as a function of the N/Z of the target for equal size systems.
A magnetotelluric study of continental lithosphere in the final stages of break-up. Afar, Ethiopia
International Nuclear Information System (INIS)
Complete text of publication follows. As part of a major programme of research into the processes and controls involved in the break-up of continents and the generation of new oceanic crust, we have collected broadband magnetotelluric data along two ∼50km long profiles in the Afar region of Ethiopia, with transient electromagnetic data for static shift control. The first is across a currently active magmatic segment that has experienced volcanic eruptions, seismic tremor and dyke injection over the last 3 years, and the other across a currently inactive segment. This presentation will concentrate on the results of the profile across the active segment. The data are broadly consistent with a two-dimensional interpretation, with geoelectrical strike along the segment's axis of rifting. Three-dimensional effects are seen primarily at sites beneath the rift axis and at longer periods. After static shift correction and rotation into TE and TM modes, we have inverted the data using the REBOCC algorithm. We find high conductivity at various depths beneath the segment axis: in a narrow zone close to the surface and in a much broader zone at depths straddling the crust-mantle interface. We interpret the deeper conductor to represent a magma chamber feeding the recent rifting episodes which has been inferred, but not previously observed directly, from a mis-match between the possible magma supply from deflation of the active volcanoes in the area and the volume of material intruded into the dykes.
Breakup structure of two-phase jets with various momentum flux from a porous injector
Lee, Inchul; Kim, Dohun; Koo, Jaye
2014-02-01
Spray structure and atomization characteristics were investigated through a comparison of a porous and a shear coaxial injector. The porous injector shows better atomization performance than the shear coaxial injector. To increase atomization performance and mixing efficiency of two-phase jets, a coaxial porous injector which can be applicable to liquid rocket combustors was designed and tested. The characteristics of atomization and spray from a porous and a shear coaxial injector were characterized by the momentum flux ratio. The breakup mechanism of the porous injector is governed by Taylor-Culick flow and axial shear forces. Momentum of injected gas flow through a porous material which is composed of sintered metal is radically transferred to the center of the liquid column, and then liquid column is effectively broken up. Although the shapes of spray from porous and shear coaxial jets were similar for various momentum ratio, spray structures such as spray angle and droplet sizes were different. As increasing the momentum flux ratio, SMD from the porous injector showed smaller value than the shear coaxial injector
Splash wave and crown breakup after disc impact on a liquid surface
Peters, Ivo R; Gordillo, J M
2012-01-01
In this paper we analyze the impact of a circular disc on a free surface using experiments, potential flow numerical simulations and theory. We focus our attention both on the study of the generation and possible breakup of the splash wave created after the impact and on the calculation of the force on the disc. We have experimentally found that drops are only ejected from the rim located at the top part of the splash --giving rise to what is known as the crown splash-- if the impact Weber number exceeds a threshold value $\\Weber_{crit}\\simeq 140$. We explain this threshold by defining a local Bond number $Bo_{tip}$ based on the rim deceleration and its radius of curvature, with which we show using both numerical simulations and experiments that a crown splash only occurs when $Bo_{tip}\\gtrsim 1$, revealing that the rim disrupts due to a Rayleigh-Taylor instability. Neglecting the effect of air, we show that the flow in the region close to the disc edge possesses a Weber-number-dependent self-similar structur...
Dark matter coupling to electroweak gauge and Higgs bosons: an effective field theory approach
Chen, Jing-Yuan; Wang, Lian-Tao
2013-01-01
If dark matter is a new species of particle produced in the early universe as a cold thermal relic (a weakly-interacting massive particle-WIMP), its present abundance, its scattering with matter in direct-detection experiments, its present-day annihilation signature in indirect-detection experiments, and its production and detection at colliders, depend crucially on the WIMP coupling to standard-model (SM) particles. It is usually assumed that the WIMP couples to the SM sector through its interactions with quarks and leptons. In this paper we explore the possibility that the WIMP coupling to the SM sector is via electroweak gauge and Higgs bosons. In the absence of an ultraviolet-complete particle-physics model, we employ effective field theory to describe the WIMP--SM coupling. We consider both scalars and Dirac fermions as possible dark-matter candidates. Starting with an exhaustive list of operators up to dimension 8, we present detailed calculation of dark-matter annihilations to all possible final states...
Fano-Kondo Effect in a Triple Quantum Dots Coupled to Ferromagnetic Leads
Institute of Scientific and Technical Information of China (English)
BI Ai-Hua; WU Shao-Quan; HOU Tao; SUN Wei-Li
2008-01-01
@@ Using the Keldysh nonequilibrium Green function and equation-of-motion technique, we have qualitatively studied the spin-dependent transport of a triple-QD system in the Kondo regime. It is shown that the Kondo resonance and Fano interference coexist, and in this system the Fano-Kondo effect shows dip behaviours richer than that in the T-shaped QDs. The interdot coupling, the energy level of the side coupled QDs and the spin polarization strength greatly influence the DOS of the central quantum dot QDo. Either the increase of the coupling strength between the two QDs or that of the energy levels of the side coupled QDs enhances the Kondo resonance. Especially, the Kondo resonance is strengthened greatly when the side dot energy is fixed at the Fermi energy. Meanwhile, the Kondo resonance splits for the spin-up and spin-down configurations due to the polarization: the down-spin resonance is enhanced, and the up-spin resonance is suppressed.
Fano–Kondo Effect in a Triple Quantum Dots Coupled to Ferromagnetic Leads
International Nuclear Information System (INIS)
Using the Keldysh nonequilibrium Green function and equation-of-motion technique, we have qualitatively studied the spin-dependent transport of a triple-QD system in the Kondo regime. It is shown that the Kondo resonance and Fano interference coexist, and in this system the Fano–Kondo effect shows dip behaviours richer than that in the T-shaped QDs. The interdot coupling, the energy level of the side coupled QDs and the spin polarization strength greatly influence the DOS of the central quantum dot QD0. Either the increase of the coupling strength between the two QDs or that of the energy levels of the side coupled QDs enhances the Kondo resonance. Especially, the Kondo resonance is strengthened greatly when the side dot energy is fixed at the Fermi energy. Meanwhile, the Kondo resonance splits for the spin-up and spin-down configurations due to the polarization: the down-spin resonance is enhanced, and the up-spin resonance is suppressed. (condensed matter: electronic structure, electrical, magnetic, and optical properties)
Shuang-Qing, W; Shuang-Qing, Wu; Mu-Lin, Yan
2003-01-01
The Hawking radiation of Weyl neutrinos in an arbitrarily accelerating Kinnersley black hole is investigated by using a method of the generalized tortoise coordinate transformation. Both the location and temperature of the event horizon depend on the time and on the angles. They coincide with previous results, but the thermal radiation spectrum of massless spinor particles displays a kind of spin-acceleration coupling effect.
Schüngel, E; Zhang, Q-Z; Iwashita, S; J. Schulze(Universität Bochum I. Institut für Experimentalphysik, Germany); Hou, L-J; Wang, Y-N; Czarnetzki, U
2011-01-01
Abstract By using a combined experimental, numerical and analytical approach, we investigate the control of plasma properties via the Electrical Asymmetry Effect (EAE) in a capacitively coupled oxygen discharge. In particular, we present the first experimental investigation of the EAE in electronegative discharges. A dual-frequency voltage source of 13.56 MHz and 27.12 MHz is applied to the powered electrode and the discharge symmetry is controlled by adjusting the phase angle ? between th...
Mixed Convection Flow of Couple Stress Fluid in a Vertical Channel with Radiation and Soret Effects
Directory of Open Access Journals (Sweden)
Kaladhar Kolla
2016-01-01
Full Text Available The radiation and thermal diffusion effects on mixed convection flow of couple stress fluid through a channel are investigated. The governing non-linear partial differential equations are transformed into a system of ordinary differential equations using similarity transformations. The resulting equations are then solved using the Spectral Quasi-linearization Method (QLM. The results, which are discussed with the aid of the dimensionless parameters entering the problem, are seen to depend sensitively on the parameters.
Effect of the Electron-LO-Phonon Coupling on an Exciton Quantum Dot
Institute of Scientific and Technical Information of China (English)
XIE Wen-Fang; ZHU Wu
2002-01-01
The influence of the electron-LO-phonon coupling on energy spectrum of the low-lying states ofan exciton inparabolic quantum dots is investigated as a function of dot size. Calculations are made by using the method of few-bodyphysics within the effective-mass approximation. A considerable decrease of the energy in the stronger confinement rangeis found for the low-lying states of an exciton in quantum dots, which results from the confinement of electron-phononcoupling.
The effects of marriage on couples' allocation of time between market and non-market hours
El Lahga, AbdelRahmen; Moreau, Nicolas
2007-01-01
We evaluate the effects of the transition from cohabitation to marriage on household domestic and market work hours using a sample of working couples. For this purpose we use the 21 first waves of the German Socio-Economic Panel (GSEOP). We adapt to system GMM estimation the estimator presented in Semykina and Wooldridge (2005) to account for selection bias in the presence of endogenous regressors. Our results indicate that marriage increases women's specialization in home-based activities an...
Institute of Scientific and Technical Information of China (English)
吴双清; 闫沐霖
2003-01-01
The Hawking radiation of Weyl neutrinos in an arbitrarily accelerating Kinnersley black hole is investigated using a method of the generalized tortoise coordinate transformation.Both the location and temperature of the event horizon depend on the time and on the angles.They are in agreement with the previous results,but thethermal radiation spectrum of massless spinor particles displays a type of spin-acceleration coupling effect.
Effects of chiral restoration on the behaviour of the Polyakov loop at strong coupling
Fukushima, Kenji
2002-01-01
We discuss the relation between the Polyakov loop and the chiral order parameter at finite temperature. For that purpose we analyse an effective model proposed by Gocksch and Ogilvie, which is constructed by the double expansion of strong coupling and large dimensionality. We make improvements in dealing with the model and then obtain plausible results for the behaviours of both the Polyakov loop and the chiral scalar condensate. The pseudo-critical temperature read from the Polyakov loop tur...
Q-factor and waveguide-sphere separation effects in waveguide-coupled microsphere resonators
Panitchob, Y.; Murugan, G.S.; M. N. Zervas; J. S. Wilkinson
2007-01-01
Quality-factors of waveguide coupled microsphere resonators of 30 ?m diameter are measured. A Teflon buffer layer is deposited on the waveguide to separate the microsphere from the waveguide and the effect of this separation on the measured quality-factor is discussed. The whispering-gallery mode propagation along the cavity of the microsphere as well as the optical path lengths of the modes are determined; the experimental and theoretical data are compared and discussed. A five-fold increase...
Understanding the effect of channel coupling on fusion of 6Li+64Ni
Moin Shaikh, Md.; Roy, Subinit
2016-07-01
The effect of inelastic excitation and single particle transfer reactions on fusion have been investigated for the system 6Li+64Ni at near barrier energies. The calculations show that a simultaneous coupling to the inelastic excitation of projectile and target along with positive Q-value 1n- and 1p-stripping channels, describes the experimental CF cross sections reasonably well in the below barrier region.
Effect of Diffraction-Coupled Apertures on the Monopole Antenna Performance
Igor Ivanchenko; Nina Popenko; Maksym Khruslov
2012-01-01
For the first time the concept of diffractioncoupled apertures is applied to the analysis of characteristics of the cylindrical monopole antennas. The information about the spatial distribution of electromagnetic fields in the radiating region of antennas is used for studying the influence of diffraction effects on the antenna performance. The optimal radius of the round hole in the ground plane center for coupling with the coaxial feeding line is determined for all the antennas under test. B...
Institute of Scientific and Technical Information of China (English)
GONG YuBing; XU Bo; MA XiaoGuang; HAN JiQu
2008-01-01
Toxins, such as tetraethylammonium (TEA) and tetrodotoxin (TTX), can make potassium or sodium ion channels poisoned, respectively, and hence reduce the number of working ion channels and lead to the diminishment of conductance. In this paper, we have studied by numerical simulations the effects of sodium and potassium ion channel poisoning on the collective spiking activity of an array of coupled stochastic Hodgkin-Huxley (HH) neurons. It is found for a given number of neurons sodium or potas-sium ion channel block can either enhance or reduce the collective spiking regularity, depending on the membrane patch size. For a given smaller or larger patch size, potassium and sodium ion channel block can reduce or enhance the collective spiking regularity, but they have different patch size ranges for the transformation. This result shows that sodium or potassium ion channel block might have dif-ferent effects on the collective spiking activity in coupled HH neurons from the effects for a single neuron, which represents the interplay among the diminishment of maximal conductance and the in-crease of channel noise strength due to the channel blocks, as well as the bi-directional coupling be-tween the neurons.
Institute of Scientific and Technical Information of China (English)
2008-01-01
Toxins, such as tetraethylammonium (TEA) and tetrodotoxin (TTX), can make potassium or sodium ion channels poisoned, respectively, and hence reduce the number of working ion channels and lead to the diminishment of conductance. In this paper, we have studied by numerical simulations the effects of sodium and potassium ion channel poisoning on the collective spiking activity of an array of coupled stochastic Hodgkin-Huxley (HH) neurons. It is found for a given number of neurons sodium or potas- sium ion channel block can either enhance or reduce the collective spiking regularity, depending on the membrane patch size. For a given smaller or larger patch size, potassium and sodium ion channel block can reduce or enhance the collective spiking regularity, but they have different patch size ranges for the transformation. This result shows that sodium or potassium ion channel block might have dif- ferent effects on the collective spiking activity in coupled HH neurons from the effects for a single neuron, which represents the interplay among the diminishment of maximal conductance and the in- crease of channel noise strength due to the channel blocks, as well as the bi-directional coupling be- tween the neurons.
Reaction mechanism for the symmetric breakup of 24Mg following an interaction with 12C
International Nuclear Information System (INIS)
Data on the yield of the symmetric breakup of 24Mg as a function of beam energy are presented and compared with detailed calculations of the energy dependence. The 24Mg states seen in symmetric breakup agree with previously observed breakup states having spin and parities Jπ=4+,(6+),8+. The data allow the variations of yield for indivual states to be judged, as the beam energy is varied. The variation in the yield of the 4+ states is compared in detail with calculations assuming several possible compound nuclear or direct reaction mechanisms. It is concluded that a massive (12C) transfer or a simple statistical compound process are unlikely mechanisms, but that each of several other mechanisms is consistent with the data. ((orig.))
International Nuclear Information System (INIS)
Motivated to understand molten corium jet falling in a water pool and fragmenting into droplets in the coolant during a hypothetical severe accident in a light water reactor (LWR), this paper presents insights on the dynamics of a coherent molten material jet and its breakup as a function of molten jet initial conditions (jet initial velocity, diameter, etc.) and material thermo-physical properties, with several corium simulant materials from low-melting temperature metallic melt (woods metal) to medium-melting temperature binary oxide melts (e.g., WO3-Bi2O3, WO3-ZrO2). A visualization system of Simultaneous High-speed Acquisition of Radiography and Photography (SHARP) is employed to quantify the characteristics of the melt jet breakup in a water pool. The experiment features well-controlled conditions and small-scale jets which can be visualized by X-ray, and therefore enables a better scrutiny of the jet breakup. (author)
Drop deformation and breakup in a partially filled horizontal rotating cylinder
White, Andrew; Pereira, Caroline; Hyacinthe, Hyaquino; Ward, Thomas
2014-11-01
Drop deformation and breakup due to shear flow has been studied extensively in Couette devices as well as in gravity-driven flows. In these cases shear is generated either by the moving wall or the drop's motion. For such flows the drop shape remains unperturbed at low capillary number (Ca), deforms at moderate Ca , and can experience breakup as Ca --> 1 and larger. Here single drops of NaOH(aq) will be placed in a horizontal cylindrical rotating tank partially filled with vegetable oil resulting in 10-2 saponification, can yield lower minimum surface tensions and faster adsorption than non-reactive surfactant systems. Oil films between the wall and drop as well as drop shape will be observed as rotation rates and NaOH(aq) concentration are varied. Results will be presented in the context of previous work on bubble and drop shapes and breakup. NSF CBET #1262718.
Research on the Rebound and Breakup of the Droplet after Impacting on the Superhydrophobic Wall
Liu, D. W.; Ning, Z.; Lü, M.; Yan, K.; Sun, C. H.
The surface hydrophilicity affects the movement of the droplet intensively when the droplet impacting on a wall, In this paper, the motion of the droplet after impacting on the superhydrophobic wall were researched by using the combined Level Set-VOF method for gas-liquid interface tracking. The results show that, the droplet would rebound after impacting on the superhydrophobic wall when the velocity is small: the droplet would breakup after when the velocity is larger; the droplet would breakup during spreading when the initial diameter is larger and less surface tension: impact angle affect the movement of the chop-let intensively after impacting on the wall. At the same time, this paper obtains critical conditions of rebound an breakup after droplet impacts on the superliydrophbic wall by vertical or inclined angle through numerical simulation in a certain range of condition.
Casal, J; Arias, J M; Gómez-Camacho, J
2016-01-01
A relationship between the Coulomb inclusive break-up probability and the radiative capture reaction rate for weakly-bound three-body systems is established. This direct link provides a robust procedure to estimate the reaction rate for nuclei of astrophysical interest by measuring inclusive break-up processes at different energies and angles. This might be an advantageous alternative to the determination of reaction rates from the measurement of $B(E1)$ distributions through exclusive Coulomb break-up experiments. In addition, it provides a reference to assess the validity of different theoretical approaches that have been used to calculate reaction rates. The procedure is applied to $^{11}$Li ($^{9}$Li+n+n) and $^6$He ($^{4}$He+n+n) three-body systems for which some data exist.
Droplet Deformation Prediction With the Droplet Deformation and Breakup Model (DDB)
Vargas, Mario
2012-01-01
The Droplet Deformation and Breakup Model was used to predict deformation of droplets approaching the leading edge stagnation line of an airfoil. The quasi-steady model was solved for each position along the droplet path. A program was developed to solve the non-linear, second order, ordinary differential equation that governs the model. A fourth order Runge-Kutta method was used to solve the equation. Experimental slip velocities from droplet breakup studies were used as input to the model which required slip velocity along the particle path. The center of mass displacement predictions were compared to the experimental measurements from the droplet breakup studies for droplets with radii in the range of 200 to 700 mm approaching the airfoil at 50 and 90 m/sec. The model predictions were good for the displacement of the center of mass for small and medium sized droplets. For larger droplets the model predictions did not agree with the experimental results.
Casal, J.; Rodríguez-Gallardo, M.; Arias, J. M.; Gómez-Camacho, J.
2016-04-01
A relationship between the Coulomb inclusive break-up probability and the radiative capture reaction rate for weakly bound three-body systems is established. This direct link provides a robust procedure to estimate the reaction rate for nuclei of astrophysical interest by measuring inclusive break-up processes at different energies and angles. This might be an advantageous alternative to the determination of reaction rates from the measurement of B (E 1 ) distributions through exclusive Coulomb break-up experiments. In addition, it provides a reference to assess the validity of different theoretical approaches that have been used to calculate reaction rates. The procedure is applied to 11Li (9Li+n +n ) and 6He (4He+n +n ) three-body systems for which some data exist.
Energy Technology Data Exchange (ETDEWEB)
Lin, Po-Yu; Gandhi, Ashish Chhaganlal; Wu, Sheng Yun, E-mail: sywu@mail.ndhu.edu.tw [Department of Physics, National Dong Hwa University, Hualien 97401, Taiwan (China)
2015-05-07
We report the influence of the nanosized effect on the superconducting properties of bimetallic In{sub 2}Bi nanoparticles. In this study, the temperature- and applied magnetic field-dependence of the magnetization were utilized to investigate the electron-phonon coupling effect while controlling particle sizes 〈d〉 from 21(2) to 42(5) nm. As the particle size decreases, the electron-phonon constant λ{sub EP} decreases rapidly, signaling the short-range electron-phonon coupling effect which acts to confine the electrons within a smaller volume, thereby giving rise to a higher superconducting transition temperature T{sub C}. An enhanced superconducting transition was observed from the temperature dependence of magnetization, revealing a main diamagnetic Meissner state below T{sub C} ∼ 5.72(5) K for 〈d〉 = 31(1) nm In{sub 2}Bi nanoparticles. The variation of the T{sub C} is very sensitive to the particle size, which might be due to crystallinity and size uniformity of the samples. The electron-phonon coupling to low lying phonons is found to be the leading mechanism for the observed strong-coupling superconductivity in the In{sub 2}Bi system.