276 research outputs found
Experiments on inductive and capacitive radiofrequency heating of a hydrogen plasma in a magnetic field
Inductive and capacitive radio frequency heating of hydrogen plasma in magnetic fiel
Spark Ignition of Flowing Gases. 2: Effect of Electrode Parameters on Energy Required to Ignite a Propane-Air Mixture
Research was conducted to determine the effect of the electrode parameters of spacing, configuration, and material' on the energy required for ignition of a flowing propane-air mixture. In addition, the data were used to indicate the energy distribution along the spark length and to confirm previous observations concerning the effect of spark duration on ignition energy requirements. The data were obtained with a mixture at a fuel-air ratio of 0.0835 (by weight), a pressure of 3 inches of mercury absolute, a temperature of 80 F, and a mixture velocity of 5 feet per second. Results showed that the energy required for ignition decreased as the electrode spacing was increased; a minimum energy occurred at. a spacing of 0.65 inch for large electrodes. For small electrodes, the spacing for minimum energy was not sharply defined. Small-diameter electrodes required less energy than large-diameter electrodes if the spacing was less than the optimum distance of 0.65 inch; at a spacing equal to the optimum distance, no difference was noted. Significant effects of electrode material on ignition energy were ascribed to differences in the type of spark discharges produced; glow discharges required higher energy than the arc-glow discharges. With pure glow discharges, the ignition energy was substantially constant for lead, cadmium, brass, aluminum, and tungsten electrodes. A method is described for determining the energy distribution along a glow discharge. It was found that one-third to one-half of the energy in the spark was concentrated in a small region near the cathode electrode, and the remainder was uniformly distributed across the spark gap. It was impossible to ascertain the dependence of ignition on. this distribution. It was also observed that long-duration (600 microsec) sparks required much less energy for ignition than did short-duration (1 microsec) sparks
Enhancement of ion cyclotron waves in hydrogen helium mixtures
Metastable helium atom addition to hydrogen plasma for ion cyclotron mode enhancemen
Spark ignition of flowing gases VI : theory of ignition in nonturbulent and turbulent flow using long-duration discharges
Spark ignition of flowing gases I : energies to ignite propane-air mixtures in pressure range of 2 to 4 inches mercury absolute
Ignition studies of flowing gases were made to obtain information applicable to ignition problems in gas-turbine and ram-jet aircraft propulsion systems operating at altitude conditions.Spark energies required for ignition of a flowing propane-air mixture were determined for pressure of 2 to 4 inches mercury absolute, gas velocities of 5.0 to 54.2 feet per second, fuel-air ratios of 0.0607 to 0.1245, and spark durations of 1.5 to 24,400 microseconds. The results showed that at a pressure of 3 inches mercury absolute the minimum energy required for ignition occurred at fuel-air ratios of 0.08 to 0.095. The energy required for ignition increased almost linearly with increasing gas velocity. Shortening the spark duration from approximately 25,000 to 125 microseconds decreased the amount of energy required for ignition. A spark produced by the discharge of a condenser directly into the spark gap and having a duration of 1.5 microseconds required ignition energies larger than most of the long-duration sparks
Spark ignition of flowing gases V : application of fuel-air-ratio and initial-temperature data to ignition theory
Spark ignition of flowing gases III : effect of turbulence promoter on energy required to ignite a propane-air mixture
Plasmonic nanogap enhanced phase change devices with dual electrical-optical functionality
Modern-day computers use electrical signaling for processing and storing data
which is bandwidth limited and power-hungry. These limitations are bypassed in
the field of communications, where optical signaling is the norm. To exploit
optical signaling in computing, however, new on-chip devices that work
seamlessly in both electrical and optical domains are needed. Phase change
devices can in principle provide such functionality, but doing so in a single
device has proved elusive due to conflicting requirements of size-limited
electrical switching and diffraction-limited photonic devices. Here, we combine
plasmonics, photonics and electronics to deliver a novel integrated
phase-change memory and computing cell that can be electrically or optically
switched between binary or multilevel states, and read-out in either mode, thus
merging computing and communications technologies
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