JUDA, WALTER (1916– ), U.S. inventor. Born in Berlin, Juda settled in the U.S. in 1939. He did research and development at the Harvard Chemistry Department from 1939 to 1948, including production of novel fungicides and fire-retardants for the war effort (1940–45) and a brackish water desalination prototype plant tested at the Weizmann Institute in the winter of 1947–48. He joined the division of industrial cooperation at the Massachussets Institute of Technology and co-founded Ionics Inc. In 1948 he became its executive vice president and technical director, until 1960, pioneering water desalting by electrodialysis; he also was a consultant to the Oak Ridge National Laboratory in 1951–54. Juda founded and ran the Prototech Company from 1960 to 1992, developing and producing gas electrodes (for electrolysis applications and fuel cells) and air pollution control catalysts. Prototech sold its electrochemistry business in 1990 and its catalyst businesses in 1992. From 1992, his third company, Hy9 Corporation (formerly Walter Juda Associates, Inc.), developed new hydrogen generation technology.