8.45. Once he or she has developed the methods needed to solve a given problem, the nuclear engineer frequently needs such specialized infor­mation as neutron cross sections, physical constants, material properties, etc. To meet this need, a number of centers have been established to maintain special collections termed data bases. In many cases, the infor­mation is stored in a computerized retrieval system that can be searched on-line by the end user. Another approach has been to collect formulations for properties and other information so that they can be made available on a suitable computer tape. Only several of the major data centers will be mentioned here. Other information sources are indicated elsewhere in the text, as appropriate.

8.46. The National Technical Information Service (NTIS) in Spring­field, Virginia maintains a very large collection of reports and other ma­terials resulting from activities of the federal government. Data bases, such as the Energy Data Base, are available for on-line searching.

8.47. The Technical Information Center at Oak Ridge, Tennessee, op­erated for the U. S. Department of Energy, is responsible for a wide variety of services, including abstracting of reports and publication of technical progress reviews. It prepares the Energy Data Base available from NTIS.

8.48. The earliest center, originally devoted primarily to nuclear cross sections, is the Brookhaven National Nuclear Data Center at Upton, New York. Data evaluation remains a major responsibility. Results are available through publications and computer tapes.

8.49. The Center for Information and Numerical Data Analysis and Synthesis (CINDAS) at West Lafayette, Indiana is an example of a data center providing engineering information. Published data describing ther­mophysical and other properties of many materials are collected and eval­uated. A data base with on-line interactive capability is maintained.