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Statistical Energy Analysis (SEA) is a very powerful tool in its ability to guide noise control package design in automobile, airplane and architectural systems. However transmission loss modeling in an SEA frame work has more to do with modeling of sound propagation through foam and fiber noise control materials than classical SEA power flow between groups of resonant modes. The transmission loss problem is reviewed in an SEA frame work with a focus on key paths and input parameter variations on predicted noise control package performance.

During the past year, considerable strides have been made toward fuel cell hardware and NASA’s Gemini and Apollo projects; work on the LEM or “bug” fuel cell is in the early stages. United States Government efforts directed at systems other than hydrogen-oxygen, primarily through the Dept. of Defense, are approaching the hardware stage via (1) reforming of hydrocarbons and their derivatives, and ammonia; (2) direct use of alcohol in low-temperature fuel cells; (3) direct use of hydrocarbons in intermediate-temperature fuel cells; (4) gasification of coal and use in high-temperature fuel cells. Commercial applications of fuel cells appear to be many years in the future, and areas of potential usefulness of fuel cells in the civilian economy are not clearly defined at present.