Abstract: A process for reducing the concentration of selenium ions in the Se(VI) oxidation state in an aqueous solution. The aqueous solution is admixed with a quantity of metallic iron. The iron reduces the selenium ions from the Se(VI) oxidation state to a lower oxidation state and then dissolves in the aqueous solution. If the pH level of the aqueous solution is above about 2.3, the selenium ions are reduced to at least the Se(IV) oxidation state and the dissolved metallic iron hydrolyses to form an iron hydroxide that precipitates. The precipitated material is separated from the aqueous solution to provide a solution having a lower concentration of selenium ions. If the pH level of the aqueous solution is below about 2.3, no iron hydrolysis is observed to occur. At least a portion of the selenium in the Se(VI) oxidation state is believed to be reduced to the elemental state. The elemental selenium then is separated from the aqueous solution to provide a solution having a lower concentration of selenium ions.

Abstract: The present invention contemplates an improved method and control apparatus for indicating the leakage resistance in an electrical system wherein the electrical system generally includes an alternating current power source connected to a load via a conductor assembly, and wherein the control apparatus generally includes: a direct current power source connected to the electrical system for impressing a direct current control signal on the electrical system, and a portion providing an output indication of the leakage resistance in the electrical system.

Abstract: An improved method and apparatus for providing an indication of the radiation activity of the radioactive decay products of radium in an environment wherein the alpha particle activity and the beta particle activity at a test site are detected and the detected alpha particle and the beta particle activities provide the indication of the radiation activity of radon and the decay products of radon at the test site. The background radiation activity at the test site is detected, and the detected alpha particle and the beta particle activities less the detected background radiation activity provide the indication of the radiation activity of radon and the decay products of radon.