News Briefs

1995 Journal of Research of the National Institute of Standards and Technology  
MD 20899-0001; telephone: 301/975-3572 . NEW WEB SITE SERVES AS GUIDE TO NII The Clinton Administration's Information Infrastructure Task Force recently launched an online resource to help people better understand benefits of the National Information Infrastructure, sometimes referred to as the "information superhighway." The NII Virtual Library home page provides any user with explanations of the NII and how it works and provides system developers with information on NII applications. The new
more » ... orld Wide Web site, co-sponsored by the IITF and the Council on Competitiveness, features links to information sites developed by universities, museums, large corporations, small businesses, government agencies, non-profit groups and other organizations with an interest in using the NII. It was developed by the IITF Committee on Applications and Technology with the support of the Office of Enterprise Integration at NIST. The site can be reached at http://nii.nist.gov by anyone with a properly equipped computer running World Wide Web browsing software, such as Mosaic or Netscape. For technical assistance when accessing the home page, contact Rick Kuhn at (301) 975-4601 or e-mail: rkuhn@nist.gov (via Internet). PHOTOVOLTAIC HOT WATER SYSTEM EXCEEDS EXPECTATIONS A full-scale prototype of a novel solar water heating system-the first to use photovoltaic cells in combination with computer technology to capture the sun's energy-has performed better than expected during testing at NIST's headquarters in Gaithersburg, MD. PV cells are semiconductor devices that convert the News Briefs energy in sunlight into electricity. These cells allow the NIST system to directly heat water in its tank, a distinct advantage over traditional devices that pump water to a rooftop solar collector and then return the heated liquid to storage. The NIST tests used a computer-based data acquisition method to withdraw hot water from the system as if used by a typical family of four. During a recent 3 month monitoring period, the NIST solar water heater provided 67 % of the total energy required versus a projected 50 % contribution. As a result, NIST engineers currently are reducing the size of the PV array by 25 % and making other modifications to yield a less expensive system. Monitoring of the revised water heater began in June. Industry partners on this project are welcomed. Contact Hunter Fanney, B320 Building Research Building, NIST, Gaithersburg, MD 20899-0001, (301) 975-5864, e-mail: hunter@micf.nist.gov (via Internet). STRESS MEASUREMENTS ASSESS RAILROAD WHEEL SAFETY Railroad wheel failure is commonly caused by cracks that propagate from the rim toward the hub. Wheels are manufactured to put the rim under residual compressive stress, which tends to close these cracks and prevent wheel failure. However, heavy braking can heat the wheel enough to make the rim stress become tensile, promoting the propagation of cracks. Detecting this reversed stress condition traditionally has been done by visual inspection of discolorations. NIST has collaborated with the Association of American Railways and two Polish research groups to develop ultrasonic methods for detecting stress in wheels. The results of this work are promising and are reported in two papers (numbers 13-95a and 13-95b) available from Sarabeth Harris, Div. 104, NIST, Boulder, (303)
doi:10.6028/jres.100.038 fatcat:ezzama7esraxrhjd2pgiujid4a