NASA scientific and technical information for the 1990s

Abstract

In this article, we outline our projections for NASA scientific and technical information (STI) in the 1990s. NASA STI for the 1990s will maintain a quality bibliographic and full-text database, emphasizing electronic input and products supplemented by networked access to a wide variety of sources, particularly numeric databases.STI for the 1990s will build on the accomplishments of the 1980s. Although budgetary realities are a constraint, there is much we can accomplish by applying new technology creatively. The changes now in process will provide a springboard for further change. CHANGING REQUIREMENTS FOR MANAGING NASA STINASA is by concept and by practice an advanced-technology agency. The thrust of the 1990s will be toward a more comprehensive, systematic use of computer and communications technology for all phases of NASA STI.Computers for STI use in the 1960s and 1970s and continuing into the 1980s were tools to assist and, where possible, replace manual operations.STI managers hoped that computerization would prove cost-effective; this was not always so. However, many new capabilities were realized. NASA will strive in the 1990s to use technology to meet new demands of users in a more cost-effective manner. The reconditioned Scientific and Technical InformationModular System (STIMS) and reconditioned RECON command and access structure are expected to be completely installed and operational at the NASA STI Facility by June 1990. This will position NASA to take advantage of state-of-the-art technology for several years into the 1990s, to handle the expected volume of electronic input and output, and to network effectively. CURRENT AND FUTURE TECHNOLOGYAs the 1980s closed, neither scientist, engineer, nor STI professional had to be convinced

Monte Carlo calculations of the dose backscatter factor for monoenergetic electrons

“…As shown in figure 10, data were fitted well by straight lines in a semi-log scale (correlation coefficients, R, generally better than 0.95), showing that the dose backscatter factor is proportional to log(Z+1). Our results clearly follow an empirical relationship, known as a log(Z + 1) dependence for electron backscattering (Seliger 1952, Rester and Dance 1967, Baily 1980, and our data confirm the validity of the log(Z + 1) relationship for the isotropic point source geometry as previously suggested by Nunes et al (1993a). Furthermore, this study shows that a log(Z + 1) dependence in such a geometry is valid up to electron energies of 3.0 MeV, for which data were lacking.…”