Power dissipation and o↵-chip bandwidth restrictions are critical challenges that limit microprocessor performance. Ternary content addressable memories (TCAM) hold the potential to address both problems in the context of a wide range of data-intensive workloads that benefit from associative search capability. Power dissipation is reduced by eliminating instruction processing and data movement overheads present in a purely RAM based system. Bandwidth demand is lowered by processing data directly on the TCAM chip, thereby decreasing o↵-chip tra c. Unfortunately, CMOSbased TCAM implementations are severely power-and arealimited, which restricts the capacity of commercial products to a few megabytes, and confines their use to niche networking applications.This paper explores a novel resistive TCAM cell and array architecture that has the potential to scale TCAM capacity from megabytes to gigabytes. High-density resistive TCAM chips are organized into a DDR3-compatible DIMM, and are accessed through a software library with zero modifications to the processor or the motherboard. On applications that do not benefit from associative search, the TCAM DIMM is configured to provide ordinary RAM functionality. By tightly integrating TCAM with conventional virtual memory, and by allowing a large fraction of the physical address space to be made content-addressable on demand, the proposed memory system improves average performance by 4⇥ and average energy consumption by 10⇥ on a set of evaluated data-intensive applications.
Gas stirring plays a significant role in steelmaking process. The stirring effect is often assessed by the mixing time. In the past, the effects of many factors such as the number and position and relative angle of porous plugs in a ladle, as well as gas flowrate on the mixing time have been studied and some beneficial results used in industrial practice. However, for a ladle with dual plugs, the researches on gas flowrate basically focused on the blowing mode with the same gas flowrates for every plug (Mode-S), while the mode with different flowrates (Mode-D) has not yet been reported. In the present work, a water model for a 120 t ladle is carried out to mainly compare the effect of the two gas blowing modes on mixing. Two porous plugs are located at 0.55-0.70R (R is the radius of ladle bottom), with different relative angles (45-180°) and total flowrates (6.92-18.45 NL/min). The results show that Mode-D can significantly change the mixing time. Compared with Mode-S, the mixing time is respectively decreased by 50 seconds at 6.92 NL/min and 30 seconds at 18.45 NL/min when the plug positions are located at 0.64R. The results of mathematical simulation explain the phenomena. In the Mode-D, the strong gas plume forms a larger circulation flow to stir the ladle and the weak plume forms a smaller one. Under this case, the interference and collision from two plumes are weakened and the dissipation of stirring energy is decreased, thus the mixing time is shortened.
Flow structures were investigated in a dissipative ladle shroud (DLS) and a tundish using Large Eddy Simulation. The numerical results were validated inside the DLS and the tundish with PIV experiments. Velocity distribution, vorticity islands and strain rate were analyzed in the DLS respectively, compared with that of a bell-shaped ladle shroud (BLS). The results showed that the three chambers of the DLS gave rise to velocity differences, fluctuating strain rates and vortices, and promoted an increase on turbulence dissipation rate; and the average velocity of outflow ranged from 0.25 to 0.5 m/s when the inlet velocity was 0.708 m/s. In the BLS, the stream flowed straightforward with relatively consistent velocity; apparent vortices were only formed in the bell end; and the outflow went down with high speed and turbulent kinetic energy. The dissipative effect of the DLS was also validated by the flow structure in the tundish. When the stream left the outlet of the DLS, it swung, got twisted and was mixed with more surrounding fluid in the tundish which decreased the mean skin friction coefficient of tundish wall and the velocity of free surface, and finally contributed to a better tundish performance.KEY WORDS: large eddy simulation; dissipative ladle shroud; bell-shaped ladle shroud; flow structure.
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