638 research outputs found

    Sequential circuit design in quantum-dot cellular automata

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    In this work we present a novel probabilistic modeling scheme for sequential circuit design in quantum-dot cellular automata(QCA) technology. Clocked QCA circuits possess an inherent direction for flow of information which can be effectively modeled using Bayesian networks (BN). In sequential circuit design this presents a problem due to the presence of feedback cycles since BN are direct acyclic graphs (DAG). The model presented in this work can be constructed from a logic design layout in QCA and is shown to be a dynamic Bayesian Network (DBN). DBN are very powerful in modeling higher order spatial and temporal correlations that are present in most of the sequential circuits. The attractive feature of this graphical probabilistic model is that that it not only makes the dependency relationships amongst node explicit, but it also serves as a computational mechanism for probabilistic inference. We analyze our work by modeling clocked QCA circuits for SR F/F, JK F/F and RAM designs

    Liner environment effects study

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    The Liner Environment Effects Study Program is aimed at establishing a broad heat transfer data base under controlled experimental conditions by quantifying the effects of the combustion system conditions on the combustor liner thermal loading and on the flame radiation characteristics. Five liner concepts spanning the spectrum of liner design technology from the very simple to the most advanced concepts are investigated. These concepts comprise an uncooled liner, a conventional film cooled liner, an impingement/film cooled liner, a laser drilled liner approaching the concept of a porous wall, and a siliconized silicon carbide ceramic liner. Effect of fuel type is covered by using fuels containing 11.8, 12.8, and 14% hydrogen. Tests at 100, 200, and 300 psia provide a basis for evaluating the effect of pressure on the heat transfer. The effects of the atomization quality and spray characteristics are examined by varying the fuel spray Sauter mean diameter and the spray angle. Additional varied parameters include reference velocity, a wide range of equivalence ratio, cooling flow rate, coolant temperature and the velocity of the coolant stream on the backside of the liner

    Experimental study of the effect of cycle pressure on lean combustion emissions

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    Experiments were conducted in which a stream of premixed propane and air was burned under conditions representative of gas turbine operation. Emissions of NOx, CO, and unburned hydrocarbons (UHC) were measured over a range of combustor inlet temperature, pressure, and residence time at equivalence ratios from 0.7 down to the lean stability limit. At an inlet temperature of 600 K, observed NOx levels dropped markedly with decreasing pressure for pressures below 20 atm. The NOx levels are proportional to combustor residence time and formation rates were principally a function of adiabatic flame temperature. For adiabatic flame temperatures of 2050 K and higher, CO reached chemical equilibrium within 2 msec. Unburned hydrocarbon species dropped to a negligible level within 2 msec regardless of inlet temperature, pressure, or equivalence ratio. For a combustor residence time of 2.5 msec, combustion inefficiency became less than 0.01% at an adiabatic flame temperature of 2050 K. The maximum combustion inefficiency observed was on the order of 1% and corresponded to conditions near the lean stability limit. Using a perforated plate flameholder, this limit is well represented by the condition of 1800 K adiabatic flame temperature

    Experimental study of the effects of flameholder geometry on emissions and performance of lean premixed combustors

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    Emissions of NOx, CO, and unburned hydrocarbons (UHC) are reported for a lean premixed propane-air system at inlet conditions of 800K and 1MPa using twelve flameholder designs. The flameholders tested represent six design concepts with two values of blockage for each concept. Data were obtained at reference velocities of 35 m/s, 25 m/s and 20 m/s at combustor stations 10 cm and 30 cm downstream of the flameholders. Flameholder pressure drop was found to be a principal determinant of emissions performance. Designs producing larger pressure drops also produced less NOx, CO, and UHC emissions. The lean stability limit equivalence ratio was found to be approximately 0.35 for all designs. Flashback velocities (axial components in the flameholder passages) varied between 30 m/s and 40 m/s. A perforated plate flameholder was operated with a velocity as low as 23 m/s through the perforations at equivalence ratio 0.7 without producing flashback

    Health, Technical Efficiency And Agricultural Production In Indian Districts

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    In this study, we attempt to quantify the effect of improved population health on technical efficiency in agricultural production. Using data for over 260 districts in 15 Indian states, we employ the random-coefficients technique to estimate a Cobb-Douglas production function, computing overall and input specific technical efficiencies for each district. We then model health (the district infant mortality rate) as a determinant of (in) efficiency in a second stage, controlling for a range of other socioeconomic variables. We find that decreases in the infant mortality rate, as well as increases in the literacy rate and level of irrigation, are associated with significant increases in overall technical efficiency, and that a good portion of healths effect is probably due to improvements in the efficiency of labor use. While efficiency increases from improvements in irrigation and literacy are larger, the potential gains from health are still fairly substantial.technical efficiency, Random coefficients model, the frontier production function

    Shadows of the Captain of the Men of Death: Health Innovation, Human Capital Investment, and Institutions

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    We leverage introduction of the first antibiotic therapies in 1937 to examine impacts of pneumonia in infancy on adult education, employment, disability, income and income mobility, and identify large impacts on each. We then examine how racial segregation in the pre-Civil Rights Era moderated the long-run benefits of antibiotics among blacks. We find that blacks born in more segregated states reaped smaller and less pervasive long run benefits despite sharp drops in pneumonia exposure. Our findings demonstrate causal effects of early life health on economic mobility and the importance of an investment-rewarding institutional environment in realization of the full potential of a healthy star

    Traffic Performance Analysis of Manet Routing Protocol

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    The primary objective of this research work is to study and investigate the performance measures of Gossip Routing protocol and Energy Efficient and Reliable Adaptive Gossip routing protocols. We use TCP and CBR based traffic models to analyze the performance of above mentioned protocols based on the parameters of Packet Delivery Ratio, Average End-to-End Delay and Throughput. We will investigate the effect of change in the simulation time and Number of nodes for the MANET routing protocols. For Simulation, we have used ns-2 simulator.Comment: 12 pages,12 figure
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