tion of Liquid-Metal Jets as the Conductor in a ated, Exploding-Fuse Opening Switc
A repetitive, high-power opening switch technique for use in pulsed power applications using inductive energy storage is presented, along with data which demonstrate performance characteristics. This technique uses jets of a liquid conductor to replace the solid metal fuses in exploding-fuse opening-switch designs. High-power switching characteristics such as interrupt current, holdoff voltage, and resistance change are presented, along with information on how these characteristics change as jet length and circuit parameters are varied. A simulated load is used to demonstrate that exploding liquid-metal jets are feasible replacements for solid-fuse conductors in realistic applications. Likewise, the switching facility has been rep-rated in a two-pulse scenario to show its primary advantage over solid-fuse switches. The use of a highspeed camera to monitor the expansion of the mercury column upon vaporization is also described. Radial expansion velocities have been extracted from the images and are correlated with the electrical data.
The Voltage across a Fuse during the Current Interruption Process
Results of experiments with fusing wires are discussed and explained theoretically. Multiple arcing is observed; it is explained in a thermodynamic model. Also, the possible absence of multiple arcing at high currents is explained. There, evaporation of superheated fuse material causes the fast increase of the fuse resistance. This evaporation explains the experimentally observed behavior of the fuse resistance as a function of fuse diameter, whereas the concept of multiple arcing fails to do so. Results from experiments confirm energy balance equations, both for fuses in air and for fuses embedded in fine-grained sand. The energy balance equation for the latter case is shown to be equivalent to Mayr's equation.
Office of the Assistant Secretary for Planning and Evaluation: national long-term care channeling demonstration program; intent to initiate program.
The poverty thresholds are the original version of the federal poverty measure. They are updated each year by the Census Bureau. The thresholds are used mainly for statistical purposes — for instance, preparing estimates of the number of Americans in poverty each year. (In other words, all official poverty population figures are calculated using the poverty thresholds, not the guidelines.) Poverty thresholds since 1973 (and for selected earlier years) and weighted average poverty thresholds since 1959 are available on the Census Bureau’s Web site. For an example of how the Census Bureau applies the thresholds to a family’s income to determine its poverty status, see “How the Census Bureau Measures Poverty” on the Census Bureau’s web site.