Software Maintenance Criteria for Small Microprocessor-Based Systems

Criteria is provided for designing and implementing small microprocessor-based programs with the objective of enhancing their maintainability properties. Since microprocessor-based programs typically have relatively short schedules and low budgets. it is necessary to adapt maintainability enhancing practices for these projects in such a manner that their impact in these critical areas is not excessive. Since many of the practices which can be used to enhance maintainability actually coincide with those which improve productivity during software development, application of those practices should incur little or no added cost or duration to a microprocessor-based program. This paper suggests practical steps which can be applied to the software design and implementation activities, to the software documentation, and to the development environment which will enhance the maintainability of the resultant computer programs.     

Analysis of gravity-wave induced instabilities and turbulence viscosity parameters from optical emissions

The effects of gravity waves on OH and 5577 0I emissions have been used to investigate (1) the possible production of “secondary” waves or “ripples” by a “primary” wave; (2) the possible application of such observed optical emissions for computing atmospheric parameters such as turbulence viscosity in the mesospheric regions.     

Correlation of oscillations of flow and temperature in floating zone under microgravity

The correlation between oscillations of flow and temperature of the Marangoni convection in a cylindric floating zone are studied. Photographs of the oscillating flow patterns are taken by triggering with a thermocouple signal of the temperature oscillation to reveal the frequency and phase correlations. Whilst both frequencies coincide, phase shift between temperature and flow oscillations exists.     

A model of the rapid burster

A new burst mode of MXB 1730 - 335, the rapid burster, as discovered by Hakucho in August 1979, is characterized by a train of long X-ray bursts whose behaviour is dictated by the accretion rate. In this mode the burst luminosity reaches the Eddington limit, so that the X-ray pressure controls the accretion from a reservoir in the magnetopause and accretion columns in the polar regions explain general features of the rapid burster observed in August 1979.     

Diamagnetic aspects of the coronal transient phenomenon

If a magnetic structure emerges into the solar atmosphere containing a preexisting magnetic field, the preexisting field must be moved aside to allow space for the emerging flux. Under these conditions, provided the ambient field strength decreases outward with radial distance, the ambient field may tend to pinch off the emerging field through magnetic reconnection and expell it outward. Here, a model is developed to demonstrate this effect and to evaluate its relevance to the coronal transient phenomenon. In particular, we argue that, if magnetic reconnection can be initiated in such a configuration, the upward force produced by the ambient field is enhanced and, depending upon the internal conditions of the configuration, a coronal transient could be initiated in this manner.     

The waves observed in the ARAKS-East experiment

Experimental results of the Wave measurements over frequency range 0.1–5.0 MHz during the second launch of the ARAKS Experiment (15.02.75) are reported. The differences between the results of the first and the second launches are discussed.     

Submicron lunar ejecta in the magnetosphere associated with meteor showers

Recent studies of the lunar ejecta from lunar impacts of interplanetary dust particles indicate that during favorable lunar phases, over 80% of the submicron ejecta enters the earth's magnetosphere. This “pulse” of lunar ejecta produced by the sporadic meteor background will follow the random variations of the sporadic flux. An additional enhancement of this flux can be related to major meteor showers. Since the annual periods of these showers occur during varying lunar phase angles, magnetosphere ejecta flux associated with major showers will vary depending on the coincidence of shower periods and favorable lunar phase angles. The results of an analysis of the “pulse” of ejecta flux in the magnetosphere during the Quadrantids, Geminids, Leonids, and Perseids meteor showers are presented. These results are compared to the satellite measurements of 1959 Eta and HEOS II.     

Scientific results from the pioneer Saturn infrared radiometer

The Pioneer 11 Infrared Radiometer instrument made observations of Saturn and its rings in broadband channels centered at 20 and 45 μm and obtained whole-disk information on Titan. A planetary average effective temperature of 96.5±2.5 K implies a total emission 2.8 times the absorbed sunlight. Correlation with radio science results implies that the molar fraction of H₂ is 90±3% (assuming the rest is He). Temperatures at the 1 bar level are 137 to 140 K; regions appearing cooler may be overlain by a cloud acting as a 124 K blackbody surface. A minimum temperature averaging 87 K is reached near 0.06 bars. Ring boundaries and optical depths are consistent with those at optical wavelengths. Ring temperatures are 64–86 K on the south (illuminated) side, ～54 K on the north (unilluminated) side, and at least 67 K in Saturn's shadow. There is evidence for a south to north drop in ring temperatures. Titan's 45 μm brightness temperature is 75±5 K.     

Effects of increased shielding on gamma-radiation levels within spacecraft.

The Shuttle Activation Monitor (SAM) experiment was flown on the Space Shuttle Columbia (STS-28) from 8-13 August, 1989 in a 57 degrees, 300 km orbit. One objective of the SAM experiment was to determine the relative effect of different amounts of shielding on the gamma-ray backgrounds measured with similarly configured sodium iodide (NaI) and bismuth germante (BGO) detectors. To achieve this objective twenty-four hours of data were taken with each detector in the middeck of the Shuttle on the ceiling of the airlock (a high-shielding location) as well as on the sleep station wall (a low-shielding location). For the cosmic-ray induced background the results indicate an increased overall count rate in the 0.2 to 10 MeV energy range at the more highly shielded location, while in regions of trapped radiation the low shielding configuration gives higher rates at the low energy end of the spectrum.