14,354 research outputs found
Fragmentation of Positronium (Ps) in collision with Li ion
Fragmentation of ground state ortho Positronium (Ps) in collision with Li ion
(Li+) is studied in the framework of post collisional Coulomb distorted eikonal
approximation (CDEA) for the target elastic case . The present model takes
account of the two center effect on the ejected e which is crucial for a proper
description of the projectile ionization involving an ionic target. Both the
fully differential (TDCS) and the doubly differential (DDCS) cross sections
(energy spectra) are investigated at intermediate and high incident energies. A
broad distinct Electron loss peak (ELP) centered around v_e ~ v_p is noted in
the e energy spectrum in contrast to the sharp ELP for a heavy projectile. Two
salient features are noted in the present study: i) the shift of the e DDCS
peak (summed over e+ angles) towards higher ejection energy with respect to
half the residual energy of the system, ii) comparison of the e& e+ energy
spectra reflect a strong e - e+ asymmetry with respect to the ratio v_e/v_p =1
>. Both these features could be attributed to the post collisional two center
effect on the e due to its parent nucleus (e+) and the screened target ion .
Two different wave functions of the Li ion are chosen in order to test the
sensitivity of the present results with respect to the choice of the wave
function.Comment: 19 pages, 7 figure
Fully-coupled analysis of jet mixing problems. Three-dimensional PNS model, SCIP3D
Numerical procedures formulated for the analysis of 3D jet mixing problems, as incorporated in the computer model, SCIP3D, are described. The overall methodology closely parallels that developed in the earlier 2D axisymmetric jet mixing model, SCIPVIS. SCIP3D integrates the 3D parabolized Navier-Stokes (PNS) jet mixing equations, cast in mapped cartesian or cylindrical coordinates, employing the explicit MacCormack Algorithm. A pressure split variant of this algorithm is employed in subsonic regions with a sublayer approximation utilized for treating the streamwise pressure component. SCIP3D contains both the ks and kW turbulence models, and employs a two component mixture approach to treat jet exhausts of arbitrary composition. Specialized grid procedures are used to adjust the grid growth in accordance with the growth of the jet, including a hybrid cartesian/cylindrical grid procedure for rectangular jets which moves the hybrid coordinate origin towards the flow origin as the jet transitions from a rectangular to circular shape. Numerous calculations are presented for rectangular mixing problems, as well as for a variety of basic unit problems exhibiting overall capabilities of SCIP3D
Response to sub-threshold stimulus is enhanced by spatially heterogeneous activity
Sub-threshold stimuli cannot initiate excitations in active media, but
surprisingly as we show in this paper, they can alter the time-evolution of
spatially heterogeneous activity by modifying the recovery dynamics. This
results in significant reduction of waveback velocity which may lead to spatial
coherence, terminating all activity in the medium including spatiotemporal
chaos. We analytically derive model-independent conditions for which such
behavior can be observed.Comment: 5 pages, 5 figure
Effect of mindfulness on online impulse buying: Moderated mediation model of problematic internet use and emotional intelligence
Introduction: Online impulse buying behavior is an unplanned urge to buy a product or service in an online setting and it has several negative consequences for customers, such as guilt and financial distress, and e-commerce firms, such as higher returns and customer complaints. Evidently, it is important to examine the various psychological processes which may assist in a better understanding, therefore addressing the high prevalence of online impulse buying. This study builds upon self-regulation theory to explore how mindfulness influences online impulse buying, and examines problematic internet use as a mediator in the relationship between mindfulness and online impulse buying. Further, this study investigates how emotional intelligence as a moderator plays the role of a suppressant on the adverse impact of problematic Internet use which fuels online impulse buying.
Method: A total of 598 individuals working with various servicebased industries responded to the questionnaire. Multiple regression and moderated mediation analysis was used using SPSS and AMOS for analyzing the data.
Result: Problematic internet use mediates the relationship between mindfulness and online impulse buying behavior. Emotional intelligence negatively moderates the relationship between problematic internet use and online impulse buying behavior.
Discussion: This study findings outlined the inverse relationship of mindfulness & online impulse buying, along with the mediating effect of problematic internet use between mindfulness and online impulse buying. Further, this study showed how emotional intelligence played an important role as a moderator by suppressing the adverse impact of problematic Internet use and preventing online impulse buying. The study offers implications to online marketers in regulating the unplanned purchase process—while minimizing uninhibited buying behavior that leads to regret, and the subsequent intention to return products. Further, social and theoretical implications are discussed
Core-tube morphology of multiwall carbon nanotubes
The present paper investigates the cross-sectional morphology of Multiwalled
Carbon Nanotubes (MWNTs) restrained radially and circumferentially by an
infinite surrounding elastic medium, subjected to uniform external hydrostatic
pressure. In this study, a two-dimensional plane strain model is developed,
assuming no variation of load and deformation along the tube axis. We find some
characteristic cross-sectional shapes from the elastic buckling analysis. The
effect of the surrounded elastic medium on the cross-sectional shape which
occurs due to pressure buckling is focused on by the comparison with the shape
for no elastic medium case in our discussion. It is suggested that in no
embedded elastic medium cases, the cross-sectional shapes of inner tubes
maintain circle or oval; on the other hand, an embedded medium may cause inner
tube corrugation modes especially when the number of shells for MWNTs is small.Comment: 7 figures, 2 figure
Collective behavior of stock price movements in an emerging market
To investigate the universality of the structure of interactions in different
markets, we analyze the cross-correlation matrix C of stock price fluctuations
in the National Stock Exchange (NSE) of India. We find that this emerging
market exhibits strong correlations in the movement of stock prices compared to
developed markets, such as the New York Stock Exchange (NYSE). This is shown to
be due to the dominant influence of a common market mode on the stock prices.
By comparison, interactions between related stocks, e.g., those belonging to
the same business sector, are much weaker. This lack of distinct sector
identity in emerging markets is explicitly shown by reconstructing the network
of mutually interacting stocks. Spectral analysis of C for NSE reveals that,
the few largest eigenvalues deviate from the bulk of the spectrum predicted by
random matrix theory, but they are far fewer in number compared to, e.g., NYSE.
We show this to be due to the relative weakness of intra-sector interactions
between stocks, compared to the market mode, by modeling stock price dynamics
with a two-factor model. Our results suggest that the emergence of an internal
structure comprising multiple groups of strongly coupled components is a
signature of market development.Comment: 10 pages, 10 figure
Modular networks emerge from multiconstraint optimization
Modular structure is ubiquitous among complex networks. We note that most
such systems are subject to multiple structural and functional constraints,
e.g., minimizing the average path length and the total number of links, while
maximizing robustness against perturbations in node activity. We show that the
optimal networks satisfying these three constraints are characterized by the
existence of multiple subnetworks (modules) sparsely connected to each other.
In addition, these modules have distinct hubs, resulting in an overall
heterogeneous degree distribution.Comment: 5 pages, 4 figures; Published versio
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