25,449 research outputs found

    The third-order law for increments in magnetohydrodynamic turbulence with constant shear

    Get PDF
    We extend the theory for third-order structure functions in homogeneous incompressible magnetohydrodynamic (MHD) turbulence to the case in which a constant velocity shear is present. A generalization is found of the usual relation [Politano and Pouquet, Phys. Rev. E, 57 21 (1998)] between third-order structure functions and the dissipation rate in steady inertial range turbulence, in which the shear plays a crucial role. In particular, the presence of shear leads to a third-order law which is not simply proportional to the relative separation. Possible implications for laboratory and space plasmas are discussed

    Caging phenomena in reactions: Femtosecond observation of coherent, collisional confinement

    Get PDF
    We report striking observations of coherent caging of iodine, above the B state dissociation threshold, by single collisions with rare gas atoms at room-temperature. Despite the random nature of the solute–solvent interaction, the caged population retains coherence of the initially prepared unbound wave packet. We discuss some new concepts regarding dynamical coherent caging and the one-atom cage effect

    Generation of non-Gaussian statistics and coherent structures in ideal magnetohydrodynamics

    Get PDF
    Spectral method simulations of ideal magnetohydrodynamics are used to investigate production of coherent small scale structures, a feature of fluid models that is usually associated with inertial range signatures of nonuniform dissipation, and the associated emergence of non-Gaussian statistics. The near-identical growth of non-Gaussianity in ideal and nonideal cases suggests that generation of coherent structures and breaking of self-similarity are essentially ideal processes. This has important implications for understanding the origin of intermittency in turbulence

    Mechanical and rheological properties of selected varieties of peppers.

    Get PDF
    Stress-relaxation rates for eight varieties of peppers were measured. The specimens were loaded at 454,907 and 1361 grams and allowed to relax for time periods of 3.8 and 30 minutes. Stress levels used were 914, 1828 and 2741 gm/cm2. Floral Gem and Jalapeno varieties of peppers received the most attention

    Possible origin of the 0.5 plateau in the ballistic conductance of quantum point contacts

    Full text link
    A non-equilibrium Green function formalism (NEGF) is used to study the conductance of a side-gated quantum point contact (QPC) in the presence of lateral spin-orbit coupling (LSOC). A small difference of bias voltage between the two side gates (SGs) leads to an inversion asymmetry in the LSOC between the opposite edges of the channel. In single electron modeling of transport, this triggers a spontaneous but insignificant spin polarization in the QPC. However, the spin polarization of the QPC is enhanced substantially when the effect of electron-electron interaction is included. The spin polarization is strong enough to result in the occurrence of a conductance plateau at 0.5G0 (G0 = 2e2/h) in the absence of any external magnetic field. In our simulations of a model QPC device, the 0.5 plateau is found to be quite robust and survives up to a temperature of 40K. The spontaneous spin polarization and the resulting magnetization of the QPC can be reversed by flipping the polarity of the source to drain bias or the potential difference between the two SGs. These numerical simulations are in good agreement with recent experimental results for side-gated QPCs made from the low band gap semiconductor InAs

    Ellipsometric measurements of the refractive indices of linear alkylbenzene and EJ-301 scintillators from 210 to 1000 nm

    Full text link
    We report on ellipsometric measurements of the refractive indices of LAB-PPO, Nd-doped LAB-PPO and EJ-301 scintillators to the nearest +/-0.005, in the wavelength range 210-1000 nm.Comment: 7 pages, 4 figure

    Incorporation of Pleurotus sajor-caju powder in cinnamon biscuit: study on nutritional, physical, colour and sensorial properties

    Get PDF
    Discovery of novel dietary fibre (DF)-rich food ingredient is of great interest to meet the rising consumer demand for healthy food. Intake of DF-enriched food has been positively associated with a decreased risk of chronic diseases. Pleurotus sajor-caju (PSC), one of the prominent edible mushrooms widely cultivated in Malaysia, is useful for its culinary and medicinal purpose. This study aimed to determine the nutritional, physical, colour and sensorial properties of cinnamon biscuit formulated with PSC powder as partial replacement (0, 4, 8 and 12%) for wheat flour. Results indicated that elevated incorporation levels of PSC powder significantly (P<0.05) increased nutritional values of cinnamon biscuits; with 12% PSC cinnamon biscuit recorded the highest DF (9.84%), protein (7.85%) and ash (1.00%) content. In texture profile analyses, slight increment in firmness and reduction in crispiness of the cinnamon biscuits were detected with increasing levels of PSC powder. PSC-enriched cinnamon biscuits were reported to have lower L* value (ranged from 65.49 to 69.25) compared to control cinnamon biscuit (70.84), indicating darker surface colour. In comparison to control cinnamon biscuit, incorporation of PSC powder up to 8% produced higher scores in term of aroma, colour and appearance. In summary, incorporation of 8% PSC powder could be an effective way to develop nutritious cinnamon biscuit without jeopardizing its desirable physical and sensorial properties

    Calculation of some properties of the vacuum

    Get PDF
    In this article, we calculate the dressed quark propagator with the flat bottom potential in the framework of the rain-bow Schwinger-Dyson equation, which is determined by mean field approximation of the global colour model lagrangian. The dressed quark propagator exhibits a dynamical symmetry breaking phenomenon and gives a constituent quark mass about 392 MeV, which is close to the value of commonly used constituent quark mass in the chiral quark model. Then based on the dressed quark propagator, we calculate some properties of the vacuum, such as quark condensate, mixed quark condensate gs<0qˉGμνσμνq0>g_{s}< 0|\bar{q}G_{\mu\nu}\sigma^{\mu\nu}q|0>, four quark condensate <0qˉΓqqˉΓq0><0|\bar{q} \Gamma q\bar{q} \Gamma q |0>, tensor, π\pi vacuum susceptibilities. The numerical results are compatible with the values of other theoretical approaches.Comment: 10 pages, 2 figures, 3 tables, some writing errors are correcte

    Phase Diagram Of The Biham-Middleton-Levine Traffic Model In Three Dimensions

    Get PDF
    We study numerically the behavior of the Biham-Middleton-Levine traffic model in three dimensions. Our extensive numerical simulations show that the phase diagram for this model in three dimensions is markedly different from that in one and two dimensions. In addition to the full speed moving as well as the completely jamming phases, whose respective average asymptotic car speeds equal one and zero, we observe an extensive region of car densities ρ\rho with a low but non-zero average asymptotic car speed. The transition from this extensive low average asymptotic car speed region to the completely jamming region is at least second order. We argue that this low speed region is a result of the formation of a spatially-limited-extended percolating cluster. Thus, this low speed phase is present in n>3n > 3 dimensional Biham-Middleton-Levine model as well.Comment: Minor clarifications, 1 figure adde
    corecore