A Purdue University committee reviewing issues concerning the "bubble fusion" research by one of its professors said yesterday that it has completed its work, but it will not make public the investigation recommendations, including any possible disciplinary action. "The committee has submitted a report, and I will take appropriate action after studying the recommendations," said Charles O. Rutledge, vice president for research, in a written statement. "Any further action in this matter will be conducted as an internal matter under appropriate university procedures." Rutledge appointed the committee in March after the British research journal Nature reported on its Web site that some researchers had raised questions about the research of Rusi Taleyarkhan, a Purdue professor of nuclear engineering, into bubble fusion, or the use of sound waves to create nuclear fusion reactions. (See "Purdue Investigates 'Bubble Fusion' Claims") Since joining the Purdue faculty in 2004 and previously at the Oak Ridge National Laboratory, Taleyarkhan published research findings in several refereed journals showing evidence that "sonofusion" generates nuclear reactions by creating tiny bubbles that implode with tremendous force. Experimental nuclear fusion reactors have historically required large, multibillion-dollar machines, but sonofusion devices might be built for a fraction of the cost and theoretically could be an unlimited source of clean energy. In addition to its potential as a "green" energy source, Taleyarkhan and other researchers said they believe sonofusion could be used in a wide range of applications from homeland security to the study of neutron stars and black holes. Taleyarkhan's findings have been controversial from the start, and Nature reported that attempts to independently confirm his results failed. Also, several researchers told Nature last spring that Taleyarkhan declined to share the raw data he claimed to have gathered in successful experiments, opposed the publication of his colleagues' negative results and, in May 2004, took the communal equipment they were using to try to replicate his work and put it in his off-campus lab. According to Nature, an analysis by Brian Naranjo of the University of California, Los Angeles, of the spectrum reported in Taleyarkhan's latest paper as proof of nuclear fusion came instead from the radioactive decay of standard lab material -- by a factor of more than 100 million. And the US Department of Energy abandoned plans to patent the process after the patent office said it would throw it out last year. Critics of the investigation are now suggesting that Purdue limited the scope of its inquiry to Taleyarkhan's alleged inappropriate research behavior and did not investigate the controversy over his research methods and results, according to a story yesterday by ScienceNOW, the online news service of Science, the research journal which first reported Taleyarkhan's bubble fusion effect observations in March 2002. ScienceNOW quotes several sonofusion experts -- whom it said are both critics and coauthors of Taleyarkhan -- as saying they were never contacted by the investigating committee. "I don't think they contacted anyone (outside Purdue) and are looking at it as a personnel matter," Ken Suslick, a sonofusion expert at the University of Illinois, Urbana-Champaign, told ScienceNOW. "God forbid they talk to anyone who knows anything," Richard Lahey Jr., a longtime collaborator of Taleyarkhan's at Rennselaer Polytechnic Institute in Troy, N.Y., told ScienceNOW. In a statement issued in March, Purdue Provost Sally Mason said, "Purdue is well aware that there are legitimate differences of scientific opinion about the theories behind Dr. Taleyarkhan's work. Those differences are the reason scientists share their findings. The research claims are very significant, and the allegations are very serious. As in any scientific endeavor, Purdue's ultimate goals are truth and integrity." "Specific recommendations of the examination committee and any subsequent steps by the university will be treated as confidential internal matters," Rutledge said in yesterday's statement. For more information, visit: www.purdue.edu