An apparatus and method for injecting a substance, such as a radiopharmaceutical, into the bloodstream of a subject is described. The apparatus comprises an injection means, such as a servo controlled syringe, a means for measuring the concentration of that substance in the subject's bloodstream, and means for controlling the injection in response to the measurement so that the concentration of the substance follows a predetermined function of time. The apparatus of the subject invention functions to inject a substance into a subject's bloodstream at a rate controlled by an error signal proportional to the difference between the concentration of the substance in the subject's bloodstream and the predetermined function.

Super-smooth rounded or formed articles made of thermoplastic materials including various poly(methyl methacrylate) or acrylonitrile-butadiene-styrene copolymers are produced by immersing the articles into a bath, the composition of which is slowly changed with time. The starting composition of the bath is made up of at least one solvent for the polymer and a diluent made up of at least one nonsolvent for the polymer and optional materials which are soluble in the bath. The resulting extremely smooth articles are useful as mandrels for laser fusion and should be useful for a wide variety of other purposes, for example lenses.

A multiple growth run with three 10 cm cartridges was carried out with the best throughput rates and time percentage of simultaneous three-ribbon growth achieved to date in this system. Growth speeds were between 3.2 and 3.6 cm/minute on all three cartridges and simultaneous full-width growth of three ribbons was achieved 47% of the time over the eight-hour duration of the experiment. Improvements in instrumentation and in the main zone temperature uniformity have been two factors that have led to more reproducible growth conditions in the multiple ribbon furnace. Factors influencing ribbon quality are being investigated through the study of the effect of ambient gas species and concentrations on material properties. Growth of ribbon with the cold shoes characteristic of the high-speed systems has shown that the properties of this ribbon respond to ambient changes in much the same way as when no cold shoes are present. The best cell efficiencies attained for 10 cm wide ribbon grown with cold shoes are still below those obtained without cold shoes (10 to 11% versus 12 to 13%, respectively). It has also been shown in these experiments that meniscus CO/sub 2/ and quartz introduced in the melt (contained in graphite crucibles) are …

Magnetic switching offers an alternative to overcoming the rep-rate and life limitations of the spark gaps in the ETA/ATA induction accelerators. The principle has been applied for many years to radar modulators but at much lower power levels and longer pulse lengths. Comparatively recent developments in magnetic materials together with some optimal circuits have made it possible to go well beyond the state of the art. A magnetic modulator has been built which steps up and compresses a 25 kV, 5 ..mu..s pulse into a 250 kV, 50 ns pulse. A second magnetic modulator has been built and installed to replace four Blumleins and spark gaps in order to provide triggers for the complete ETA injector and accelerator. The paper outlines some practical and theoretical considerations affecting the design of the magnetic pulse generator.

The long term residual heat removal for the Clinch River Breeder Reactor Plant (CRBRP) is accomplished through the use of three protected air-cooled condensers (PACC's) each rated at 15M/sub t/ following a normal or emergency shutdown of the reactor. Steam is condensed by forcing air over the finned and coiled condenser tubes located above the steam drums. The steam flow is by natural convection. It is drawn to the PACC tube bundle for the steam drum by the lower pressure region in the tube bundle created from the condensing action. The concept of the tube bundle employs a unique patented configuration which has been commercially available through CONSECO Inc. of Medfore, Wisconsin. The concept provides semi-parallel flow that minimizes subcooling and reduces steam/condensate flow instabilities that have been observed on other similar heat transfer equipment such as moisture separator reheaters (MSRS). The improved flow stability will reduce temperature cycling and associated mechanical fatigue. The PACC is being designed to operate during and following the design basis earthquake, depressurization from the design basis tornado and is housed in protective building enclosure which is also designed to withstand the above mentioned events.