* Howard George has been appointed chief financial officer, vice president of finance and corporate secretary for Ceradyne Inc., a Costa Mesa manufacturer of technical ceramics. He succeeds James F. Gardner, who resigned earlier this month but will continue as a consultant for six months. George has more than 15 years' experience in manufacturing companies.
* Ron Holder has joined Prolux Corp., a San Juan Capistrano designer of projection systems, as chief operations officer. He will initially head implementation of the company's manufacturing division. Holder previously worked as an outside consultant for Prolux.
* Nick S. Marikian has been appointed vice president and banking officer of the sales and service division of Chino Valley Bank. He will work at the Fullerton office. He was formerly senior vice president and regional manager for California United Bank. Before that, Marikian was senior vice president and regional manager for Community Bank in Industry.
* Michael J. Clinton has joined the Commercial Equipment Finance division of Heller Financial Inc. as senior account executive and assistant vice president. He will be based out of Costa Mesa. Clinton was a marketing representative in Southern California for General Electric Capital Corp. for eight years.
* David Nagel has been named editor of ResponseTV, a publication of Advanstar Publishing in Santa Ana directed to the electronic merchandising industry. He has been managing editor since 1994.
* William O'Connell has been installed as chairman of the board of the Anaheim/Orange County Visitor & Convention Bureau. He is general manager of Best Western Stovall's Inn.