An ultimate shutdown system is provided for termination of neutronic activity in a nuclear reactor. The shutdown system includes bead chains comprising spherical containers suspended on a flexible cable. The containers are comprised of mating hemispherical shells which provide a ruggedized enclosure for reactor poison material. The bead chains, normally suspended above the reactor core on storage spools, are released for downward travel upon command from an external reactor monitor. The chains are capable of horizontal movement, so as to flow around obstructions in the reactor during their downward motion.

This invention provides an antenna arrangement for accurately measuring the magnetic permeability of earth formations. It provides a high-resolution coil array of a transmitting coil and six receiving coils to enable self-consistency checks for evaluating tight gas and oil-bearing strata. (DLC)

The invention is an improvement to an intruder-detection system of the kind where intruder-induced signals are transmitted through a medium whose conductance varies with certain climatic conditions. The improved system includes means coupled to the medium for converting the intruder-induced signals received therefrom to a first electrical signal. Means also are provided for generating a reference signal proportional to the climate-induced changes in the signal-conductance of the medium. Means are provided for generating, from the first electrical signal and the reference signal, an electrical output signal which is unaffected by the changes in signal-conductance. Means are provided to give warning when the output signal exceeds a selected value. In another aspect, the invention is a method for operating an intruder-detection system of the kind wherein an intrusion-generated signal transmitted through a detection medium is converted to a first electrical signal. The first electrical signal contains variations resulting from climate-induced changes in the medium. The method of the invention comprises generating an electrical reference signal proportional to the climate-induced changes in the medium; conditioning the first signal with the reference signal to produce an electrical output signal which is unaffected by the climate-induced changes in the medium; and impressing the resulting …

Novel substituted coumarin compounds and an improved method for their synthesis are disclosed. The preferred class of compounds are substituted at the 7-position. The method of synthesis comprises reacting a polyhydroxy benzene or a substituted phenol, with a ..beta..-alkoxy acrylic acid or nitrile, in the presence of a Lewis acid catalyst. By the inclusion of the catalyst in the reaction mixture, the reaction can be carried out under much milder experimental conditions and in increased yields. The method is also applicable to the preparation of substituted amino phenols.