Adaptive Latency Insensitive Protocols andElastic Circuits with Early Evaluation: A Comparative Analysis

AbstractLatency Insensitive Protocols (LIP) and Elastic Circuits (EC) solve the same problem of rendering a design tolerant to additional latencies caused by wires or computational elements. They are performance-limited by a firing semantics that enforces coherency through a lazy evaluation rule: Computation is enabled if all inputs to a block are simultaneously available. Adaptive LIP's (ALIP) and EC with early evaluation (ECEE) increase the performance by relaxing the evaluation rule: Computation is enabled as soon as the subset of inputs needed at a given time is available. Their difference in terms of implementation and behavior in selected cases justifies the need for the comparative analysis reported in this paper. Results have been obtained through simple examples, a single representative case-study already used in the context of both LIP's and EC and through extensive simulations over a suite of benchmarks

Field Testing of Different Chemical Combinations as Odour Baits for Trapping Wild Mosquitoes in The Gambia

Odour baited traps have potential use in population surveillance of insect vectors of disease, and in some cases for vector population reduction. Established attractants for human host-seeking mosquitoes include a combination of CO2 with L-lactic acid and ammonia, on top of which additional candidate compounds are being tested. In this field study in rural Gambia, using Latin square experiments with thorough randomization and replication, we tested nine different leading candidate combinations of chemical odorants for attractiveness to wild mosquitoes including anthropophilic malaria vectors, using modified Mosquito Magnet-X (MM-X) counterflow traps outside experimental huts containing male human sleepers. Highest catches of female mosquitoes, particularly of An. gambiae s.l. and Mansonia species, were obtained by incorporation of tetradecanoic acid. As additional carboxylic acids did not increase the trap catches further, this ‘reference blend’ (tetradecanoic acid with L-lactic acid, ammonia and CO2) was used in subsequent experiments. MM-X traps with this blend caught similar numbers of An. gambiae s.l. and slightly more Mansonia and Culex mosquitoes than a standard CDC light trap, and these numbers were not significantly affected by the presence or absence of human sleepers in the huts. Experiments with CO2 produced from overnight yeast cultures showed that this organic source was effective in enabling trap attractiveness for all mosquito species, although at a slightly lower efficiency than obtained with use of CO2 gas cylinders. Although further studies are needed to discover additional chemicals that increase attractiveness, as well as to optimise trap design and CO2 source for broader practical use, the odour-baited traps described here are safe and effective for sampling host-seeking mosquitoes outdoors and can be incorporated into studies of malaria vector ecology

INVESTMENT BEHAVIOR AND ENERGY CONSERVATION

Binary logit and bivariate probit models were used to investigate the investment behavior of farmers relative to two energy-conserving assets, heat-recovery systems and precoolers. The bivariate probit procedure was useful in correcting for self-selectivity bias. Holdout samples and cross-validation procedures were used to develop true model statistics. Farm size, educational level of the operator, and the type of milking system in use were the important factors influencing investment behavior.Farm Management,

Field testing of different chemical combinations as odour baits for trapping wild mosquitoes in The Gambia.

Odour baited traps have potential use in population surveillance of insect vectors of disease, and in some cases for vector population reduction. Established attractants for human host-seeking mosquitoes include a combination of CO(2) with L-lactic acid and ammonia, on top of which additional candidate compounds are being tested. In this field study in rural Gambia, using Latin square experiments with thorough randomization and replication, we tested nine different leading candidate combinations of chemical odorants for attractiveness to wild mosquitoes including anthropophilic malaria vectors, using modified Mosquito Magnet-X (MM-X) counterflow traps outside experimental huts containing male human sleepers. Highest catches of female mosquitoes, particularly of An. gambiae s.l. and Mansonia species, were obtained by incorporation of tetradecanoic acid. As additional carboxylic acids did not increase the trap catches further, this 'reference blend' (tetradecanoic acid with L-lactic acid, ammonia and CO(2)) was used in subsequent experiments. MM-X traps with this blend caught similar numbers of An. gambiae s.l. and slightly more Mansonia and Culex mosquitoes than a standard CDC light trap, and these numbers were not significantly affected by the presence or absence of human sleepers in the huts. Experiments with CO(2) produced from overnight yeast cultures showed that this organic source was effective in enabling trap attractiveness for all mosquito species, although at a slightly lower efficiency than obtained with use of CO(2) gas cylinders. Although further studies are needed to discover additional chemicals that increase attractiveness, as well as to optimise trap design and CO(2) source for broader practical use, the odour-baited traps described here are safe and effective for sampling host-seeking mosquitoes outdoors and can be incorporated into studies of malaria vector ecology

The mechanics of submerged multiport diffusers for bouyant discharges in shallow water

Prepared by the Ralph M. Parsons Laboratory for Water Resources and Hydrodynamics in association with the Energy LaboratoryA submerged multiport diffuser is an effective device for disposal of water containing heat or other degradable wastes into a natural body of water. A high degree of dilution can be obtained and the environmental impact of concentrated waste can be constrained to a small area. An analytical and experimental investigation is conducted for the purpose of developing predictive methods for buoyant discharges from submerged multiport diffusers. The following physical situation is considered: A multiport diffuser with given length, nozzle spacing and vertical angle of nozzles is located on the bottom of a large body of water of uniform depth. The ambient water is unstratified and may be stagnant or have a uniform current which runs at an arbitrary angle to the axis of the diffuser. The general case of a diffuser in arbitrary depth of water and arbitrary buoyancy is treated. However, emphasis is put on the diffuser in shallow receiving water with low buoyancy, the type used for discharge of condenser cooling water from thermal power plants. A multiport diffuser will produce a general three-dimensional flow field. Yet the predominantly two-dimensional flow which is postulated to exist in the center portion of the three-dimensional diffuser cart be analyzed as a two-dimensional "channel model", that is a diffuser section bounded by walls of finite length and openings at both ends into a large reservoir. Matching of the solutions for the four distinct flow regions which can be discerned in the channel model, namely, a buoyant jet region, a surface impingement region, an internal hydraulic jump region and a stratified counterflow region, yields these results: The near-field zone is stable only for a limited range of jet densimetric Froude numbers and relative depths. The stability is also dependent on the jet discharge angle. It is only in this limited range that previous buoyant jet models assuming an unbounded receiving water are applicable to predict dilutions. Outside of the parameter range which yields stable near-field conditions, the diffuser-induced dilutions are essentially determined by the interplay of two factors: frictional effects in the far-field and the horizontal momentum input of the jet discharge. Three far-field flow configurations are possible, a counter flow system, a stagnant wedge system and a vertically fully mixed flow, which is the extreme case of surface and bottom interaction. A three-dimensional model for the diffuser-induced flow field is developed. Based on equivalency of far-field effects, the predictions of the two-dimensional channel model can be linked to the three-dimensional diffuser characteristics. Diffusers with an unstable near-field produce three-dimensional circulations which lead to recirculation at the diffuser line: effective control of these circulations is possible through horizontal nozzle orientation. The diffuser in an ambient cross-current is studied experimentally. Different extreme regimes of diffuser behaviour can be described. Performance is dependent on the arrangement of the diffuser axis with respect to the crossflow direction. Experiments are performed in two set-ups, investigating both two- dimensional slots and three-dimensional diffusers. Good agreement between theoretical predictions and experimental results is found. The results of this study are presented in form of dilution graphs which can be used for three-dimensional diffuser design or preliminary design if proper schematization of the ambient geometry is possible. Design considerations are discussed and examples are given. For more complicated ambient conditions, hydraulic scale models are necessary. The results of this study indicate that only undistorted scale models simulate the correct areal extent of the temperature field and the interaction with currents, but are always somewhat conservative in dilution prediction. The degree of conservatism can be estimated. Distorted models are less conservative in predicting near-field dilutions, but exaggerate the extent of the near-field mixing zone.Stone and Webster Engineering Corp., Boston, Mass., Long Island Lighting Co., Hicksville, New York, and the National Science Foundation, Engineering Energetics Program. GK-3247

Applications of thermal energy storage in the cement industry

In the manufacture of cement, literally trillions of Btu's are rejected to the environment each year. The purpose of this feasibility study program was to determine whether thermal energy storage could be used to conserve or allow alternative uses of this rejected energy. This study identifies and quantifies the sources of rejected energy in the cement manufacturing process, established use of this energy, investigates various storage system concepts, and selects energy conservation systems for further study. Thermal performance and economic analyses are performed on candidate storage systems for four typical cement plants representing various methods of manufacturing cement. Through the use of thermal energy storage in conjunction with waste heat electric power generation units, an estimated 2.4 x 10 to the 13th power Btu/year, or an equivalent on investment of the proposed systems are an incentive for further development

Explicit Energy-Minimal Short-Term Path Planning for Collision Avoidance in Crowd Simulation

In traditional crowd simulation methods, global path planning (GPP) and local collision avoidance (LCA) were mostly used to advance pedestrians toward their own goals without colliding. However, we found that using those methods in bidirectional flows can force a pedestrian to get stuck among the incoming people, walk through the congestion, or even unintentionally occupy in a dense area, although more comfortable passageway exists. These odd behaviors are usually produced and simply noticeable in bidirectional case. This paper aims at reducing these artifacts to achieve more behavioral fidelity, by adding the explicit metabolic-energy-minimal short-term path planning (MEM) in between GPP and LCA. For energy analysis, the optimal control theory with the objective energy function from the study of biomechanics was employed, which finally leads to the useful optimal walking characteristics for the pedestrians. The simulation results show that the pedestrians with MEM can adapt their moving to avoid the congestion, resulting in more promising lane changing and overtaking behaviors. Even though MEM was mainly developed to deal with the artifacts in bidirectional flows, it can be extended with a little modification and can produce significant behavioral improvement for multi-directional case as shown in the last part of the paper

Numerical Simulation on Methane Coal Dust Composite Explosion in Restricted Space by Ultrafine Water Mist Suppression

The purpose of this experimental investigation was to examine the effects of ultrafine water mist on explosions caused by methane and coal dust hybrids that occurred inside of a closed vessel. In this study, we built a small-scale semi-closed visualization experimental platform and ran simulations to study the effects of four factors on the explosion of methane coal mixtures: the amount of ultra-fine water mist sprayed, the volume fraction of methane, the position of the methane inlet, and the amount of time it took to premix. This allowed us to gain a deeper understanding of the repressive effect of this water mist on methane explosion. The findings demonstrate that ultrafine water mist is capable of suppressing methane explosions, with a notable inhibitory effect on 10% methane. This inhibitory effect becomes stronger with increasing amounts of sprayed ultrafine water mist. The effect of methane volume fraction on the maximum explosion overpressure