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1.
Goodarz Ahmadi 《International Journal of Engineering Science》1985,23(1):1-25
A continuum theory for multiphase particulate suspensions in a fluid media is formulated. The generalized fundamental balance laws for the particulate phases as well as for the continuous suspending fluid phase are presented. The thermodynamics of a multiphase system is studied and the method of Lagrangian multipliers is employed to include the constraints of incompressibility of materials of the constituents and the criterion for fully saturated media. Constitutive equations are developed which include microrotational and microdilatational effects. The basic equations of motion of different phases are derived and discussed. Special considerations are given to the case of incompressible constituents. Examples of applications of the present theory to dilute suspension flows and multiphase sedimentations are also discussed. 相似文献
2.
The Journal of Supercomputing - 相似文献
3.
Hajipour Abdol R. Khorsandi Zahra Ahmadi Mehnoosh Jouypazadeh Hamidreza Mohammadi Bahareh Farrokhpour Hossein 《Catalysis Letters》2021,151(10):2842-2850
Catalysis Letters - Several highly efficient and magnetically recyclable cobalt catalytic systems were prepared using magnetic chitosan and some safe and available organic compounds... 相似文献
4.
The relationship between chemical structure and reactivity for thermal hydroprocessing was studied for five gas oils derived from Alberta bitumens. Chemical structure was characterized by combining data from 1 H and 13 C nuclear magnetic resonance spectroscopy, class fractionation, and elemental analysis to calculate structural parameters. Thermal hydrotreating was performed in a continuous-flow stirred reactor at 420 and 440°C, 13.9 MPa hydrogen pressure, and 1.5 h1 LHSV. Conversion of the 343–525°C boiling fraction of the gas oils was correlated with the concentration of naphthenic methylene groups in the feed. Formation of methane and ethane was dependent on the degree of condensation of the aromatic rings in the feed oils. Thermal desulfurization was highly correlated with the amount of saturates in the feed, and the aromaticity of the resin fraction. Hydrogen consumption increased with the aromaticity of the gas oil… 相似文献
5.
Hamed Ahmadi Saman Zad Tootaghaj Mahmoud Reza Hashemi Shervin Shirmohammadi 《Multimedia Systems》2014,20(5):485-501
The widespread availability of broadband internet access and the growth in server-based processing have provided an opportunity to run games away from the player into the cloud and offer a new promising service known as cloud gaming. The concept of cloud gaming is to render a game in the cloud and stream the resulting game scenes to the player as a video sequence over a broadband connection. To meet the stringent network bandwidth requirements of cloud gaming and support more players, efficient bit rate reduction techniques are needed. In this paper, we introduce the concept of game attention model (GAM), which is basically a game context-based visual attention model, as a means for reducing the bit rate of the streaming video more efficiently. GAM estimates the importance of each macro-block in a game frame from the player’s perspective and allows encoding the less important macro-blocks with lower bit rate. We have evaluated nine game video sequences, covering a wide range of game genre and a spectrum of scene content in terms of details, motion and brightness. Our subjective assessment shows that by integrating this model into the cloud gaming framework, it is possible to decrease the required bit rate by nearly 25 % on average, while maintaining a relatively high user quality of experience. This clearly enables players with limited communication resources to benefit from cloud gaming with acceptable quality. 相似文献
6.
The effect of electrostatic and capillary forces on bumpy particle adhesion and removal in turbulent flows is studied. We use the JKR theory and account for the increase of adhesion by capillary force. The effects of electrostatic forces and nonlinear hydrodynamic drag are included in the analyses. The criteria for incipient rolling and sliding detachments and electrostatic lifting removal are evaluated. A turbulence burst model is used for evaluating the peak air velocity near the substrate. The critical shear velocities for detaching particles of different sizes under different conditions are evaluated. The electric field strength needed for electrostatic removal of particles with different charges is also estimated. The results are compared with those obtained in the absence of the capillary force. Comparisons of the model predictions with the available experimental data are also presented. 相似文献
7.
Electropolymerization of pyrrole on lead substrate electrode was studied. Due to electrochemical activity of Pb in acidic media, this process is only possible at basic pHs. For this purpose, electropolymerization process was performed in an aqueous solution of Na2SO4 with pH 12. Potentiodynamic cycling shows the Pb oxidation at the first cycles. In subsequent cycles, polypyrrole film grows on the oxidized lead substrate. Of course, as the passive film is highly porous, a composite of polypyrrole/PbSO4 is formed in the first layers. However, subsequent cycling leads to the formation of pure polypyrrole film. According to this structure and strong connection of the polymer film to the substrate surface via this composite layer, the polypyrrole film deposited on the lead surface has enhanced mechanical stability. AFM measurements showed peculiar smoothness of both composite and lateral polypyrrole films. This synthesis approach is of particular interest for the preparation of highly stable polymer films and fabrication of supercapacitors with a polymer/PbSO4 conductive structure. 相似文献
8.
Multimedia Tools and Applications - Image retargeting is the task of making images capable of being displayed on screens with different sizes. This work should be done so that high-level visual... 相似文献
9.
10.
Fine sediment represents an important diffuse source pollutant in surface waters, due to its role in governing the transfer and fate of many substances, including nutrients, heavy metals, pesticides and other organic contaminants, and its influence on aquatic ecology. Therefore, catchment management strategies frequently need to include provision for the control of sediment mobilization and delivery. The sediment tracing concept provides a valuable framework for assisting the management and control of diffuse source sediment pollution by identifying the key sources and demonstrating the importance of intermediate storages and the likely impact of upstream mitigation strategies on downstream sediment and sediment associated contaminant fluxes. In this research, fine sediment sources were identified using tracing method. By field works, sediments were sampled from dam reservoir, different sources were also sampled. Fifteen tracers were first selected for tracing which are: The amounts of N, P, C, Cr, Co, Mg, K, Na, smectite, chlorite, illite, kaolinite, and two magnetic properties consisting of LOW Frequency Magnetic Susceptibility (X(LF)) and Frequency Dependent Magnetic Susceptibility (X(FD)). The samples were analyzed in the laboratory for these parameters and different statistical methods were applied to the data including Non-parametric Kruskal-Wallis Test and Stepwise Discriminant function analysis. The results provide important information on the relative importance of fine sediment sources to the reservoir sediments, which can be used to support model validation and the targeting of management and control strategies. 相似文献