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991.
Much has been written about the development of a general systems theory for application to civil problems, but very little documentation exists in the sense of case studies of large-scale programs implemented using the systems approach. The Model Urban Neighborhood Demonstration Program, operating in an inner-city poverty neighborhood in Baltimore, offers some lessons in this regard. With the present state of the art, the techniques of systems analysis are most effective at the subsystem level, and the necessary funding and development time should be afforded to extend their usefulness in the civil order. Existing aerospace companies provide an operating institutional base, with extenasive resources, that can be beneficially translated to solving problems in the public order. 相似文献
992.
S. Bowyer G.M. Zeitlin J. Tarter M. Lampton W.J. Welch 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1983,3(9):105
Parasitic programs for the Search for Extraterrestrial Intelligence (SETI), carried out concurrently with conventional radio astronomical observing programs, can be an attractive and cost-effective means of exploring the large multidimensional search space intrinsic to this effort. We describe a microprocessor-based automated SETI acquisition system which searches for and records spectra of narrowband signals in the IF band of an observatory receiver. Data taken with this system over 35 days at the Hat Creek Radio Observatory at 1612 MHz are discussed. Out of approximately 105 spectra processed during this period, 4000 were identified by the system as containing narrowband signals and were recorded. Subsequent analysis indicates that over 3900 of these are due to local RF contamination. The remainder are undergoing further investigation. 相似文献
993.
D.J. Hofmann J.M. Rosen N.T. Kjome G.L. Olson D.W. Martell 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1985,5(1):31-34
Over 500 small scientific balloons have been launched by the University of Wyoming's Atmospheric physics Group from 26 locations over the globe in a study of stratospheric aerosol physics and chemistry which began in 1971. These flights have led to a basic understanding of the evolution of sulfurous gases, injected into the stratosphere by major volcanic eruptions, into sulfuric acid aerosol droplets. The recent use of new, thin film balloon technology, to reduce cost and simplify launch techniques, has been a major advantage to the program. 相似文献
994.
In 1983 the NSIA sponsored the first Integrated Diagnostics National Conference. The major finding from this Conference was the lack of integration of those technologies which are part of the diagnostic process. Since that time, much has been done to implement the concept of integrated diagnostics. The NSIA has produced a baseline report on the implementation of the concept. This was followed by a series of Service programs aimed at implementation. The Office of the Secretary of Defense considers solutions to the diagnostic problem to be one of its major R&D goals. This paper discusses the progress made during the last three years on the implementation of integrated diagnostics. The paper also discusses the author's ideas on where the program is going. 相似文献
995.
F. Frontera D. Dal Fiume W. Dusi E. Morelli G. Spada G. Ventura 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1984,3(10-12)
The transient X-ray pulsar A0535+26 was observed on October 4, 1980 during a high level intensity outburst with a balloon borne hard X-ray detector. High statistical quality source spectra were determined up to 100 keV. Both blackbody and Wien laws fit well the data. Pulse phase spectroscopy shows variation of temperature index between 7.5 and 8.5 keV in the off source spectra and between 7.4 and 10.5 keV in the off pulse spectra. The time averaged luminosity above 30 keV is 8×1036 erg/s. 相似文献
996.
The body rate dynamics of a spin-stabilized satellite are perturbed by white noise. We consider the optimal control of body rates and fuel consumption. The corresponding deterministic problem is solved using calculus of variation. The stochastic problem is then solved to obtain a suboptimal controller in closed form. 相似文献
997.
Cole D.W. Mott W.E. Sagan L.A. 《IEEE transactions on aerospace and electronic systems》1969,(2):134-141
Radioisotope power supplies for heart assist devices and total replacements are being developed. In a radioisotopically powered artificial heart, heat from the decay of radioisotopes would be converted to fluid power to operate a blood pump. Radioisotope power sources offer the advantages of being completely implantable and having a relatively long life. Initial efforts have been directed toward developing conceptual designs of radioisotope heat engines, evaluating candidate radioisotopes fuel forms, and studying the radiation doses to be expected from the various fuel forms. Conceptual design studies indicate that a power supply capable of meeting the specifications of a circulatory support system can be developed. The most promising fuel is plutonium-238. Radiation does not appear to be a problem. 相似文献
998.
A.N. Parmar J.L. Culhane C.G. Rapley K.J.H. Phillips C.J. Wolfson L.W. Acton B.R. Dennis 《Advances in Space Research (includes Cospar's Information Bulletin, Space Research Today)》1982,2(11):151-154
The Bent Crystal Spectrometer on the NASA Solar Maximum Mission satellite provides high spectral and temporal resolution observations of the Fe Kα lines. We have analysed spectra from almost 50 solar flares that occurred during 1980. These data strongly support fluorescent excitation of photospheric iron by photons of E > 7.11 keV emitted by the hot coronal plasma produced during the flare. After comparison of the data with a model, we discuss the observed Kα line widths, estimates of the size of the emitting region, the height of the coronal source and the photospheric iron abundance. 相似文献
999.
R.K. Crouch A.L. Fripp W.J. Debnam I.O. Clark P.G. Barber F.M. Carlson 《Acta Astronautica》1985,12(11):923-929
Lead-tin-telluride has been grown in a thermally stable mode (solutally unstable) and in a solutally stable (thermally unstable) mode in a Bridgman configuration. Significant differences in the crystal morphology and the compositional homogeneity have been found between the two configurations. In addition, for the solutally stable configuration, evidence has been found that the flow characteristics in the melt change drastically during the course of the run. 相似文献
1000.
Many satellites, especially those equipped with solar panels, are of concave shape. The calculation of the aerodynamic forces on concave bodies exposed to a free molecular flow is complicated due to shielding effects of one surface by another and due to the multiple molecular collisions between these surfaces. In this paper the flow into concave corners is treated. It is shown that shielding has an influence on the surface forces, only for certain corner angles and flow incidence angles. 相似文献