Fuel cells incorporating ion exchange membranes - current state of development.
Ion exchange single and double membrane fuel cell performance limits including product water removal and power density considerations
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Ion exchange single and double membrane fuel cell performance limits including product water removal and power density considerations
Joint maximum likelihood estimates for signal amplitude and noise power density in coherent pulse code modulation channel with white Gaussian noise and correlation receiver
Joint maximum likelihood estimator for signal amplitude and noise power density in coherent PCM CHANNEL with white Gaussian noise
Photovoltaic conversion - multikilowatt solar arrays with specific power densities approaching 40 lb/kW
Feasibility of using Fourier transforms in expressions of cross spectral density and power spectral density in spectral human response analyses
Cylindrical geometry thermionic converter with vapor deposited W emitter, noting power density performance characteristics, work function and long term stability
Rhenium Nb cylindrical thermionic converter, measuring efficiency and power density in emitter temperature range 1600-2050 K and collector temperature range 873-1173 K
Cylindrical thermionic converter with vapor deposited rhenium emitter and niobium collector, measuring efficiency and power density
RF high pressure plasma discharges contained within radial inflow vortex, measuring radiation efficiencies, power densities and radiation fluxes
Electron-beam generator produces high quality welds without vaporization by relying on the mobility and hydrodynamic properties of the material in its liquid phase. The power density of the beam is relative to the speed of the workpiece, producing an inclined weld-front.
Particle beam power density detection and measurement apparatus
Mo/Mo cylindrical thermionic converter steady state performance, measuring efficiency and power density at various low emitter and collector temperatures
Harmful biological effects caused by exposure to microwave radiation including radio frequency power density in vicinity of space station antennas
Development of a high temperature, high power density, isothermal, rapid transient, infrared thermal module is described. The investigation of various alternative approaches is discussed, as well as the rationale leading to the choice of a carbon cloth concept. Evolution of module design configurations and a summary of the development test results are included, along with a detailed description of the final design, which incorporated a black plate emitter radiantly heated by the carbon cloth. The final module configuration met design criteria during a 200-hour thermal vacuum performance test at 1000 F operating temperature without contaminating a solar cell array.
Outputs are presented for some cesium diodes having primarily emitters of highly oriented polycrystalline or single-crystal 110 tungsten or .0001 rhenium. Power densities at 10 A/sq cm or 0.5 V appear as functions of emitter temperatures and electrode spacings.
The nonlinear evolution of unstable sound waves in a uranium plasma has been calculated using a multiple time-scale asymptotic expansion scheme. The fluid equations used include the fission power density, radiation diffusion, and the effects of the changing degree of ionization of the uranium atoms. The nonlinear growth of unstable waves is shown to be limited by mode coupling to shorter wavelength waves which are damped by radiation diffusion. This mechanism limits the wave pressure fluctuations to values of order delta P/P approximates 0.00001 in the plasma of a typical gas-core nuclear rocket engine. The instability is thus not expected to present a control problem for this engine.
Fuel samples, 90UC - 10 ZrC, and chemically vapor deposited tungsten fuel cups were fabricated for the study of the long term dimensional stability and compatibility of the carbide-tungsten fuel-cladding systems under irradiation. These fuel samples and fuel cups were assembled into the fuel pins of two capsules, designated as V-2E and V-2F, for irradiation in NASA Plum Brook Reactor Facility at a fission power density of 172 watts/c.c. and a miximum cladding temperature of 1823 K. Fabrication methods and characteristics of the fuel samples and fuel cups prepared are described.
The nonlinear evolution of unstable sound waves in a uranium plasma has been calculated using a multiple time-scale asymptotic expansion scheme. The fluid equations used include the fission power density, radiation diffusion, and the effects of the changing degree of ionization of the uranium atoms. The nonlinear growth of unstable waves is shown to be limited by mode coupling to shorter wavelength waves which are damped by radiation diffusion. This mechanism limits the wave pressure fluctuations to values of order delta P/P equal to about .00001 in the plasma of a typical gas-core nuclear rocket engine. The instability is thus not expected to present a control problem for this engine.