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991.
S. Ali 《Frontiers of Physics》2016,11(3):115201
The electrostatic potential caused by a test-charge particle in a positive dust-electron plasma is studied, accounting for the dust-charge fluctuations associated with ultraviolet photoelectron and thermionic emissions. For this purpose, the set of Vlasov–Poisson equations coupled with the dust charging equation is solved by using the space–time Fourier transform technique. As a consequence, a modified dielectric response function is obtained for dust-acoustic waves in a positive dust-electron plasma. By imposing certain conditions on the velocity of the test charge, the electrostatic potential is decomposed into the Debye–Hückel (DH), wake-field (WF), and far-field (FF) potentials that are significantly modified in the limit of a large dust-charge relaxation rate both analytically and numerically. The results can be helpful for understanding dust crystallization/coagulation in twocomponent plasmas, where positively charged dust grains are present. 相似文献
992.
Nikita S. Gibanov Mikhail A. Sheremet Muneer A. Ismael Ali J. Chamkha 《Transport in Porous Media》2017,116(1):1-18
Accurate prediction of the macroscopic flow parameters needed to describe flow in porous media relies on a good knowledge of flow field distribution at a much smaller scale—in the pore spaces. The extent of the inertial effect in the pore spaces cannot be underestimated yet is often ignored in large-scale simulations of fluid flow. We present a multiscale method for solving Oseen’s approximation of incompressible flow in the pore spaces amid non-periodic grain patterns. The method is based on the multiscale finite element method [MsFEM Hou and Wu in J Comput Phys 134:169–189, 1997)] and is built in the vein of Crouzeix and Raviart elements (Crouzeix and Raviart in Math Model Numer Anal 7:33–75, 1973). Simulations of inertial flow in highly non-periodic settings are conducted and presented. Convergence studies in terms of numerical errors relative to the reference solution are given to demonstrate the accuracy of our method. The weakly enforced continuity across coarse element edges is shown to maintain accurate solutions in the vicinity of the grains without the need for any oversampling methods. The penalisation method is employed to allow a complicated grain pattern to be modelled using a simple Cartesian mesh. This work is a stepping stone towards solving the more complicated Navier–Stokes equations with a nonlinear inertial term. 相似文献
993.
El-Mahdy M. Ameen Hesham A. Ali Mofreh M. Salem Mahmoud Badawy 《International Journal of Theoretical Physics》2017,56(8):2376-2412
This paper investigates a novel architecture to the problem of quantum computer programming. A generalized architecture for a high-level quantum programming language has been proposed. Therefore, the programming evolution from the complicated quantum-based programming to the high-level quantum independent programming will be achieved. The proposed architecture receives the high-level source code and, automatically transforms it into the equivalent quantum representation. This architecture involves two layers which are the programmer layer and the compilation layer. These layers have been implemented in the state of the art of three main stages; pre-classification, classification, and post-classification stages respectively. The basic building block of each stage has been divided into subsequent phases. Each phase has been implemented to perform the required transformations from one representation to another. A verification process was exposed using a case study to investigate the ability of the compiler to perform all transformation processes. Experimental results showed that the efficacy of the proposed compiler achieves a correspondence correlation coefficient about R ≈ 1 between outputs and the targets. Also, an obvious achievement has been utilized with respect to the consumed time in the optimization process compared to other techniques. In the online optimization process, the consumed time has increased exponentially against the amount of accuracy needed. However, in the proposed offline optimization process has increased gradually. 相似文献
994.
In the present paper we explore the Hawking radiation as a quantum tunneling effect from a rotating 5 dimensional Myers-Perry black hole (5D-MPBH) with two independent angular momentum components. First, we investigate the Hawking temperature by considering the tunneling of massive scalar particles and spin-1 vector particles from the 5D-MPBH in the Painlevé coordinates and then in the corotating frames. More specifically, we solve the Klein-Gordon and Proca equations by applying the WKB method and Hamilton-Jacobi equation in both cases. Finally, we recover the Hawking temperature and show that coordinates systems do not affect the Hawking temperature. 相似文献
995.
M.M. Rahman R.K. Agarwal T. Siikonen 《International Journal of Computational Fluid Dynamics》2016,30(2):89-106
A simplified consistency formulation for Pk/ε (production to dissipation ratio) is devised to obtain a non-singular Cμ (coefficient of eddy-viscosity) in the explicit algebraic Reynolds stress model of Gatski and Speziale. The coefficient Cμ depends non-linearly on both rotational/irrotational strains and is used in the framework of an improved RAS (Rahman–Agarwal–Siikonen) one-equation turbulence model to calculate a few well-documented turbulent flows, yielding predictions in good agreement with the direct numerical simulation and experimental data. The strain-dependent Cμ assists the RAS model in constructing the coefficients and functions such as to benefit complex flows with non-equilibrium turbulence. Comparisons with the Spalart–Allmaras one-equation model and the shear stress transport k-ω model demonstrate that Cμ improves the response of RAS model to non-equilibrium effects. 相似文献
996.
997.
Famiza Latif Madzlan Aziz Ab Malik Marwan Ali Muhd Zu Azhan Yahya 《Macromolecular Symposia》2009,277(1):62-68
In this research, thin, soft and flexible free standing films can be obtained from poly (methyl methacrylate) (PMMA)/50% epoxidised natural rubber (ENR 50)/lithium triflate (LiCF3SO3) blends. However, phase separation is observed on the surface of the films which indicates that the blending is not homogeneous. The blend became more homogeneous when ethylene carbonate (EC) plasticizer is introduced into the blend system. However, the anti-plasticization effect of EC on ENR 50 occurs at lower concentration of EC at which the rubber became coagulated due to immiscibility of the rubber with EC plasticizer during solution casting. These ENR 50 coagulates can be observed as large solid structures in the Field Emission Scanning Electron Microscope (FESEM) micrographs of the EC-plasticized rubber-based electrolytes. The presence of these coagulates, hinder the migration of lithium ions in the system and also trap the lithium ions within the coil. This in turn reduced the number of free lithium ions that contribute to the ionic conduction. As a result, the conductivity of the un-plasticized PMMA/ENR 50/LiCF3SO3 film dropped drastically by two orders of magnitude. 相似文献
998.
Sheikhahmadi Haidar Mohammadi Abolhassan Aghamohammadi Ali Harko Tiberiu Herrera Ramón Corda Christian Abebe Amare Saaidi Khaled 《The European Physical Journal C - Particles and Fields》2019,79(12):1-10
The European Physical Journal C - We study the Yukawa model with one scalar and one axial scalar fields, coupled to N copies of Dirac fermions, in curved spacetime background. The theory possesses... 相似文献
999.
Bingcheng Lin Qunxing Huang Mujahid Ali Fei Wang Yong Chi Jianhua Yan 《Proceedings of the Combustion Institute》2019,37(3):3101-3108
Continuous catalytic pyrolysis of oily sludge was carried out in a special U-shape reactor for producing saturates-enriched light oil. The sludge underwent thermal pyrolysis first and then catalytic pyrolysis. During the thermal pyrolysis, chain hydrocarbons were first cracked and further polymerized into aromatics. The effect of temperatures (400–800 °C) on the products was investigated and the maximum liquid yield (67.7%) was obtained at 500 °C. High temperature promoted polymerization, thus the distribution of aromatics in the liquid product was increased and was more concentrated in polyaromatics at 800 °C. In the catalytic upgrading stage, dolomite was used as catalyst and aromatics were adsorbed on it, either aggregated or decomposed. As a result, a light oil product with 57.0% saturates was obtained at the residence time of 8.9?s due to the conversion of aromatics and heavy hydrocarbons into light aliphatic hydrocarbons such as straight chain hydrocarbons. Compared with the oil phase in the raw sludge sample, the content of saturates was increased by 45.0% and that of the asphaltenes was reduced by 88.5%. Meanwhile, the inherent moisture in the oily sludge could participate in the steam reforming reaction, promoting the decomposition of aromatics and leading to an increase in the H2 generation. Moreover, the release of H2S was reduced from 0.132 to 0.005?mol per kg sludge and the sulfur content of the oil product was also decreased in the presence of dolomite. The deactivation of dolomite can be attributed to the carbonization of CaO and deposition of polyaromatic coke on the catalyst surface. 相似文献
1000.
The surface tensions of ternary and quaternary systems of Sn-based Pb-free solder alloys have been calculated using geometric models, such as Muggianu, Kohler, Chou’s general solution model (GSM), Toop, Guggenheim, ideal Butler and Butler models. It is observed from the calculation carried out in the present work that Sb and Bi contents decrease the surface tension of the solder alloys Sn-Zn-Sb-Bi. It is inferred from the statistical analysis that the best agreement between the experimental results and the corresponding calculated values of the surface tensions is generally observed in GSM and Muggianu models among the geometric models. Whereas Muggianu model is the most appropriate. Relatively good agreements have been observed between models considered in this study and experimental data. 相似文献