Supernova 1987A: Rotation and a Binary Companion

In this paper we provide a possible link between the structure of the bipolar nebula surrounding SN1987A and the properties of its progenitor star. A Wind Blwon Bubble (WBB) scenario is emplyed, in which a fast, tenuous wind from a Blue Supergiant expands into a slow, dense wind, expelled during an earlier Red Supergiant phase. The bipolar shapre develops due to a pole-to-equator density contrast in the slow wind (ie, the slow wind forms a slow torus). We use the Wind Compressed Disk (WCD) model of Bjorkman & Cassinelli (1992) to determine the shape of the slow torus. In the WCD scenario, the shape of the torus is determined by the rotation of the progenitor star. We then use a self-similar semi-analytical method for wind blown bubble evolution to determine the shape of the resulting bipolar nebula. We find that the union of the wind-compressed-disk and bipolar-wind-blown- bubble models allows us to recover the salient properties of SN1987A's circumstellar nebula. In particular, the size, speed and density of SN1987A's inner ring are easily reproduced in our calculations. An exploration of parameter space shows the the red supergiant progenitor must be been rotating at > 0.3 of its breakup speed. We conclude that the progenitor was most likely spun up by a merger with a binary companion. Using a simple model for the binary merger we find that the companion is likely to have had a mass > 0.5 M_sun.Comment: 30 pages, 4 figure

Investigation of self-help oil-spill response techniques and equipment

The US Coast Guard commissioned Pacific Northwest Laboratory (PNL) to conduct this study of 45 self-help oil-spill response techniques and equipment for oceangoing tankers and inland tank barges to assess the potential effectiveness of the proposed countermeasure categories. This study considers the hypothetical outflow of oil in the case of side damage and bottom damage to single-hull designs. The results will be considered by the Coast Guard in drafting regulations pertaining to the requirement for tanker vessels to carry oil pollution response equipment (i.e., in response to the oil Pollution Act of 1990). PNL's approach to this investigation included: assessing time-dependent oil outflow in the cases of collision and grounding of both tankers and barges; identifying environmental constraints on self-help countermeasure operation; identifying human factor issues, such as crew performance, safety, and training requirements for the self-help countermeasures considered; and assessing each self-help countermeasure with respect to its potential for minimizing oil loss to the environment. Results from the time-dependent oil outflow, environmental limitations, and human factors requirements were input into a simulation model

Automation impact study of Army training management 2: Extension of sampling and collection of installation resource data

This automation impact study of Army training management (TM) was performed for the Army Development and Employment Agency (ADEA) and the Combined Arms Training Activity (CATA) by the Battelle Human Affairs Research Centers and the Pacific Northwest Laboratory. The primary objective of the study was to provide the Army with information concerning the potential costs and savings associated with automating the TM process. This study expands the sample of units surveyed in Phase I of the automation impact effort (Sanquist et al., 1988), and presents data concerning installation resource management in relation to TM. The structured interview employed in Phase I was adapted to a self-administered survey. The data collected were compatible with that of Phase I, and both were combined for analysis. Three US sites, one reserve division, one National Guard division, and one unit in the active component outside the continental US (OCONUS) (referred to in this report as forward deployed) were surveyed. The total sample size was 459, of which 337 respondents contributed the most detailed data. 20 figs., 62 tabs

Automation impact study of Army Training Management

The main objectives of this impact study were to identify the potential cost savings associated with automated Army Training Management (TM), and to perform a cost-benefit analysis for an Army-wide automated TM system. A subsidiary goal was to establish baseline data for an independent evaluation of a prototype Integrated Training Management System (ITMS), to be tested in the fall of 1988. A structured analysis of TM doctrine was performed for comparison with empirical data gathered in a job analysis survey of selected units of the 9ID (MTZ) at Ft. Lewis, Washington. These observations will be extended to other units in subsequent surveys. The survey data concerning staffing levels and amount of labor expended on eight distinct TM tasks were analyzed in a cost effectiveness model. The main results of the surveys and cost effectiveness modelling are summarized. 18 figs., 47 tabs