Advanced Dispenser Cathodes
Controlled porosity reservoir cathodes offer significantly improved performance over conventional impregnated cathodes. Optimized performance requires additional design to achieve reduced barium deposition on adjacent surfaces, increased lifetime, and high current density emission. This paper describes the achievable performance and the associated design requirements.
The mechanism of sintering of copper
Abstract A study of the sintering of copper has been made using specimens prepared by winding 0.0128 or 0.00526 cm dia. copper wires around copper spools. Changes in the size and shape of the voids between wires were observed as a function of sintering time and temperature. By these means it was possible to investigate both bonding and shrinkage in all stages of sintering. It is concluded that shrinkage in all stages is primarily due to the volume diffusion of atoms from grain boundary sources to the voids. During the initial stages of sintering bonding occurs by the above mechanism and also by volume diffusion between differently curved free surfaces of the voids. These conclusions are consistent with the following results: 1. (1) shrinkage stops when the grain boundaries disappear. 2. (2) shrinkage rates calculated on the basis of the volume diffusion mechanism agree reasonably well with observed rates. 3. (3) the temperature dependence agrees with the volume diffusion mechanism. 4. (4) the sintering scaling law for volume diffusion is found to hold for the wires of different sizes.
Thermal properties of the Florida Current as related to Ocean Thermal Energy Conversion (OTEC)
The thermal properties of the Florida Current are presented and analyzed for the available ocean thermal energy. For a cold water intake depth equal to or greater than 600 m, potential sites for Ocean Thermal Energy Conversion (OTEC) power plants appear to exist in the Straits of Florida and, to a lesser extent, off the coasts of Georgia and South Carolina. The maximum thermal differences occur on the continental shelf because of the geostrophic motion of the Gulf Stream. An estimate of the total available ocean thermal energy from the Florida Current, delivered in the form of electricity, is 3.5 × 1012 kWh yr−1. For a cold water suction depth of 600 m or more, seasonal variability in the ocean thermal resource is approx. ±35 per cent of average annual output.