19948642
Interfacial behavior of complex hydrocarbon fluids at elevated pressures and temperatures
Unlike all the physical properties of the bulk fluid phases, interfacial tension (IFT) is unique in the sense that it relates to the interface between the two immiscible fluid phases. Hence, interfacial tension between the fluid phases can be used to infer a great deal of information about solubility, miscibility and mass transfer interactions between the two bulk fluid phases in contact.In this paper, we examine the utility of interfacial tension to characterize miscibility and mass transfer mechanisms using complex hydrocarbon fluids at elevated pressures and temperatures.For CO2/n-decane system at 37.8 /spl deg/C the minimum miscibility pressure (MMP) determined using the VIT technique (7.9 MPa) matched well with the reported MMPs by slim-tube (8.2-8.6 MPa) and rising-bubble techniques (8.8 MPa). For CO2M-C1+ n-C4+ n-CW techniques system at 71.1 /spl deg/C the VIT technique resulted in an MMP value of 12.2 MPa, which is in good agreement with the published values of slim-tube and phase diagram measurements (11.7 MPa) and analytical model predictions (11.7 MPa). This paper discusses the multiple roles of interfacial tension with supporting experimental data obtained at elevated pressures and temperatures and emphasizes the need to recognize interfacial tension as a good phase behavior indicator in fluid-fluid phase equilibria for more efficient use of this fundamental property in several other applications.
206821455
Compositional dependence of wetting and contact angles in solid-liquid-liquid systems under realistic environments
The wetting and contact angles in porous media are important for the characterization of multi-phase flow behavior. The polar components such as asphaltenes in the oil-phase, which have been widely believed to be a major source of oil-wetting characteristics. The effect of light gaseous ends in crude oil on wetting is studied by depleting the pressure at regular intervals. The variation of contact angles observed with the pressure during the pressure depletion clearly showed the influence of light ends on wetting. The water-advancing contact angle of live crude oil gradually increased from 55/spl deg/ at bubble point pressure to 154/spl deg/ at ambient pressure. The de-asphaltened and the deresined crude oils showed strong oil-wet characteristics as stocktank crude oil. The light gaseous ends in oil phase appear to peptize the asphaltene molecules by surrounding them, thereby preventing their agglomeration and migration to the interface. The differences observed in the behavior of dynamic interfacial tensions between live and stocktank crude oils further substantiates the influence of light gaseous ends on the activity of polar components in live oil. The influence of solid surface roughness, mineralogy of rock substrates as well as the brine composition on wetting and contact angles have also been investigated. For highly smooth substrates, carbonate and silica showed relatively similar high water-advancing contact angles, while for rough substrates, the advancing contact angles on silica were much lower compared to the carbonates.
30164221
Limited feedback design for MIMO broadcast channels with ARQ mechanism
We investigate the design of a limited feedback mechanism for multiple-input-multiple-output (MIMO) broadcast systems that are equipped with automatic repeat request (ARQ) capabilities. Given multiple antennas at the base-station (BS) and single antenna subscribers, we focus on maximizing the ergodic system sum capacity and propose an adaptive feedback bit allocation scheme under the constraint of total feedback bandwidth. Furthermore, we develop two efficient feedback allocation schemes based on asymptotic analysis. We present simulation results that verify the effectiveness of the proposed adaptive allocation schemes.
17935039
Data manipulation techniques to reduce phase change memory write energy
Due to its great scalability potential, phase change memory has become a topic of great current interest. However, high write energy consumption appears to be one of the biggest challenges to be tackled before phase change memory can be adopted as a mainstream memory technology. This paper presents architecture level technique to reduce phase change memory write energy consumption through data manipulations. Motivated by the fact that phase change memory read incurs much less energy than write and write of different value to a phase change memory cell incurs largely different energy, we present two memory write data manipulation techniques that can effectively reduce the overall memory write energy consumption. Their effectiveness has been demonstrated based on mathematical analysis and computer system simulation using phase change memory as the main memory in the computer memory hierarchy. Significant energy savings with up to more than 60% have been shown over a wide range of computer system benchmarks.
38063423
A series of explicit and exact travelling wave solutions of the B(m, n) equations
Abstract In this paper, explicit and exact travelling wave solutions of B ( m ,  n ) equations are investigated by using a generalized algebraic method. A series of explicit exact solutions, such as solitary wave, triangular periodic, rational, Jacobi and Weierstrass elliptic function periodic solutions are obtained. Many new results are presented.
43547034
Thirteen limit cycles for a class of cubic Hamiltonian system with higher-order perturbed terms
Abstract The number and distribution of limit cycles of a cubic Hamiltonian system under higher-order perturbed terms is investigated. By using the bifurcation theory and the method of detection function, we obtain that there exist at least 13 limit cycles with the distribution C 7 1 ⊃ 2 [ C 3 2 ⊃ 2 C 1 2 ] in the Hamiltonian system under the perturbed term of degree 5. Additionally, various distributions of limit cycles are given by numerical exploration.
26522967
Maximum entropy model-based baseball highlight detection and classification
In this paper, we propose a novel system that is able to automatically detect and classify baseball highlights by seamlessly integrating image, audio, and speech clues using a unique framework based on maximum entropy model (MEM). What distinguishes our system is that we emphasize on the integration of multimedia features and the acquisition of domain knowledge through automatic machine learning processes. Our MEM-based framework provides a simple platform capable of integrating multimedia features as well as their contextual information in a uniform fashion. Unlike the Hidden Markov Model and the Bayes Network-based approaches, this framework does not need to explicitly segment and classify the input video into states during its data modeling process, and hence remarkably simplifies the training data creation and the highlight detection/classification tasks. Experimental evaluations demonstrate the superiority of our proposed baseball highlight detection system in its capability of detecting more major baseball highlights, and in its overall accuracy of detecting these major highlights.