3,342 research outputs found
Hybrid stars within the framework of the Sigma-Omega-Rho model combined with the MIT and NJL models
In this paper, we investigate the structure of hybrid stars consisting of
hadrons (neutrons, protons, sigmas, lambdas), leptons (electrons, muons), and
quarks (up, down, strange). We use a relativistic mean-field (RMF) model namely
the Sigma-omega-rho model for the hadronic phase and the MIT bag model as well
as the NJL model for the quark phase. In addition, Maxwell and Gibbs conditions
are employed to investigate the hadron-Quark phase transition. Finally, by
obtaining the mass-radius relation, is predicted
for such hybrid stars.Comment: 23 pages, 10 figure
LOCV calculations for polarized liquid with the spin-dependent correlation
We have used the lowest order constrained variational (LOCV) method to
calculate some ground state properties of polarized liquid at zero
temperature with the spin-dependent correlation function employing the
Lennard-Jones and Aziz pair potentials. We have seen that the total energy of
polarized liquid increases by increasing polarization. For all
polarizations, it is shown that the total energy in the spin-dependent case is
lower than the spin-independent case. We have seen that the difference between
the energies of spin-dependent and spin-independent cases decreases by
increasing polarization. We have shown that the main contribution of the
potential energy comes from the spin-triplet state.Comment: 14 pages, 5 figures. Int. J. Mod. Phys. B (2008) in pres
Quantifying Spatiotemporal Chaos in Rayleigh-B\'enard Convection
Using large-scale parallel numerical simulations we explore spatiotemporal
chaos in Rayleigh-B\'enard convection in a cylindrical domain with
experimentally relevant boundary conditions. We use the variation of the
spectrum of Lyapunov exponents and the leading order Lyapunov vector with
system parameters to quantify states of high-dimensional chaos in fluid
convection. We explore the relationship between the time dynamics of the
spectrum of Lyapunov exponents and the pattern dynamics. For chaotic dynamics
we find that all of the Lyapunov exponents are positively correlated with the
leading order Lyapunov exponent and we quantify the details of their response
to the dynamics of defects. The leading order Lyapunov vector is used to
identify topological features of the fluid patterns that contribute
significantly to the chaotic dynamics. Our results show a transition from
boundary dominated dynamics to bulk dominated dynamics as the system size is
increased. The spectrum of Lyapunov exponents is used to compute the variation
of the fractal dimension with system parameters to quantify how the underlying
high-dimensional strange attractor accommodates a range of different chaotic
dynamics
Prediction of Water Activity Coefficient in TEG-Water System Using Diffusion Neural Network (DNN)
Accurate determination of activity coefficients of water in a binary triethylene glycol (TEG)-water system, is of prime concern in designing the natural gas dehydration process. In this work, a hybrid model (a combination of information diffusion theory and neural network) and a so-called diffusion neural network (DNN) have been developed for the prediction of activity coefficients of a binary TEG-water system. Owing to the insufficient experimental data available in the literature for binary mixtures, and in particular
for infinite dilution, we have employed the information diffusion technique as a tool in extrapolating data points from the original data. By means of this technique, a new dataset has been trained and optimized for the DNN model with more nodes in the input
and the output layers. The result of this study reveals that DNN model is superior to the conventional neural nets in predicting the activity coefficient of water in the range of temperature (293–387.6 K) and mole fractions with mean absolute error of 0.31 %
(MAE = 0.31 %), and high correlation coefficient of 0.999 (r = 0.999). Furthermore, the results of this work using DNN have also been compared with Parrish’s correlation. The findings of this work demonstrate that the DNN model exhibits better results over Parrish’s correlation in predicting the activity coefficients of water in a binary triethylene glycol-water system with a mean absolute error of 5.03 percent (MAE = 5.03 %)
Spin-to-Orbital Angular Momentum Conversion and Spin-Polarization Filtering in Electron Beams
We propose the design of a space-variant Wien filter for electron beams that
induces a spin half-turn and converts the corresponding spin angular momentum
variation into orbital angular momentum of the beam itself by exploiting a
geometrical phase arising in the spin manipulation. When applied to a spatially
coherent input spin-polarized electron beam, such a device can generate an
electron vortex beam, carrying orbital angular momentum. When applied to an
unpolarized input beam, the proposed device, in combination with a suitable
diffraction element, can act as a very effective spin-polarization filter. The
same approach can also be applied to neutron or atom beams.Comment: 9 pages, 5 figure
Evaluation of the Behavior of Native Iranian Pistachio Species as Rootstocks
Abstract The aim of this research was evaluate the seedling behavior of among Pistacia species can be used as rootstock in pistachio. Differences in stem diameter were observed among the species. The thickest stems were developed by P. atlantica (5.67 mm), P. vera cv. 'Qazvini' (25.47mm) and 'Badami-e-Riz-e-Zarand' (5.13 mm) whereas the thinnest stems were measured in P. atlantica subsp. kurdica (3.48 mm), P. atlantica subsp. mutica (3.52 mm) and P. atlantica subsp. cabulica (3.84 mm). P. atlantica produced more leaf number per seedling than the other species and cabulica had the most SPAD index. The correlation between various morphological traits showed that a few growth characters were significantly correlated with echophysiological. However, leaf dry weight was in significant correlation with RWC for P. vera cv. 'Badami-e-Riz-e-Zarand' and 'Sarakhs', fresh weight of leaf for P. khinjuk and P. atlantica subsp. kurdica, shoot dry weight was in correlation with stomata resistance for P. atlantica subsp. mutica and cabulica and leaf fresh weight and dry weight negatively correlated with SPAD for P. atalntica
Hydrodynamic instabilities in gaseous detonations: comparison of Euler, Navier–Stokes, and large-eddy simulation
A large-eddy simulation is conducted to investigate the transient structure of an unstable detonation wave in two dimensions and the evolution of intrinsic hydrodynamic instabilities. The dependency of the detonation structure on the grid resolution is investigated, and the structures obtained by large-eddy simulation are compared with the predictions from solving the Euler and Navier–Stokes equations directly. The results indicate that to predict irregular detonation structures in agreement with experimental observations the vorticity generation and dissipation in small scale structures should be taken into account. Thus, large-eddy simulation with high grid resolution is required. In a low grid resolution scenario, in which numerical diffusion dominates, the structures obtained by solving the Euler or Navier–Stokes equations and large-eddy simulation are qualitatively similar. When high grid resolution is employed, the detonation structures obtained by solving the Euler or Navier–Stokes equations directly are roughly similar yet equally in disagreement with the experimental results. For high grid resolution, only the large-eddy simulation predicts detonation substructures correctly, a fact that is attributed to the increased dissipation provided by the subgrid scale model. Specific to the investigated configuration, major differences are observed in the occurrence of unreacted gas pockets in the high-resolution Euler and Navier–Stokes computations, which appear to be fully combusted when large-eddy simulation is employed
A Comparison between Recombinant Activated Factor VII (Aryoseven) and Novoseven in Patients with Congenital Factor VII Deficiency
In order to establish the efficacy and biosimilar nature of AryoSeven to NovoSeven in the treatment of congenital factor VII (FVII) deficiency, patients received either agent at 30 1/4g/kg, intravenously per week for 4 weeks, in a randomized fashion. The primary aim was to compare FVII:coagulation activity (FVII:C), 20 minutes after recombinant activated FVII (rFVIIa) injection, in the 2 groups. A secondary measure was self-reported bleeding. The median interquartile baseline range of the plasma level of activated FVII (FVIIa) activity in the 2 groups was 1.6 (1.1-14.0) IU/dL and 5.0 (1.1-25.5) IU/dL. All patients achieved levels of FVIIa (FVII:C) >30 IU/dL, 20 minutes after the injection of rFVIIa. Bleeding was similar between the 2 groups, with a comparable decrease in severity and frequency compared to the last month prior to treatment. AryoSeven is similar to NovoSeven in increasing postinjection FVIIa activity as well as in clinical safety and efficacy. © The Author(s) 2014
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