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At least 1,531 records · Page 85

Redshifts of low-X-ray luminosity clusters of galaxies

Measurements of redshifts and velocity dispersions are presented for Abell clusters A539, A1185, and A1228, and the southern clusters S1840-623, S1904-618, S1908-566, and S2000-561. All these clusters have reported X-ray luminosities or upper limits. Finding charts for the clusters are presented, and the measured heliocentric redshifts are given along with redshifts obtained by other investigators. Comments are made about each cluster. The technique used to derive the redshifts is summarized.

Kowalski, M. P.↗

Tropical-extratropical geopotential height teleconnections during the Northern Hemisphere winter

Simultaneous and lagged correlation patterns between height anomalies in the Northern Hemisphere (NH) or in the Southern Hemisphere (SH) and height anomalies at tropical stations in two major tropical precipitation zones (the Indochina maritime continent and Africa) were examined. The height anomalies among the tropical stations in these zones and its nearby Pacific Ocean, South America, and Africa are strongly correlated; they are also correlated with stations in Australia and the North PLacific Ocean. The correlations between height anomalies at any of these stations and NH height anomalies show a well-defined global pattern with major features concentrated in the United States and adjacent oceans. Depending upon the location of the stations, the pattern is either a Pacific North American (PNA), a Tropical NH (TNH), or a mixed pattern having both elements. During the El Nino/Southern Oscillation (ENSO) years both TNH and PNA patterns appear in simultaneous and lagged maps, but in non-ENSO years the TNH is weak in simultaneous charts.

Mo, Kingtse C.↗

A two-dimensional air-to-air combat game - Toward an air-combat advisory system

Air-to-air combat is modeled as a discrete differential game, and by constraining the game to searching for the best guidance laws from the sets of those considered for each opponent, feedback and outcome charts are obtained which can be used to turn one of the automatic opponents into an intelligent opponent against a human pilot. A one-on-one two-dimensional fully automatic, or manned versus automatic, air-to-air combat game has been designed which includes both attack and evasion alternatives for both aircraft. Guidance law selection occurs by flooding the initial-condition space with four simulated fights for each initial condition, depicting the various attack/evasion strategies for the two opponents, and recording the outcomes. For each initial condition, the minimax method from differential games is employed to determine the best choice from the available strategies.

Neuman, Frank↗

Dynamical factors affecting ozone mixing ratios in the Antarctic lower stratosphere

An account is given of the climatology and interannual variability of dynamical quantities and ozone mixing ratios during the Southern Hemisphere spring for 1979-1984. The seasonal variation in temperature in the lower stratosphere is repeatable; a steep decrease in zonal mean ozone mixing ratios is observed around 60 deg S toward the South Pole in September which, with time, becomes shallower in association with minor warmings and a final warming. Climatological synoptic charts in the lower stratosphere show the circumpolar circulation in the geopotential height field and the prominence of planetary wave 1 in the temperature and ozone fields. When wave activity is strong, there are weaker westeries, higher temperatures, and higher ozone mixing ratios at high latitudes.

Shiotani, Masato↗

Computer Interface For A Spectroreflectometer

FORTRAN program controls stepping motors and signal-processing electronics via S-100 computer bus. Group of spectroreflectometers modified to provide computer-controlled operation and data collection. Analog and digital signal-processing circuits enable use of computerized automatic data collection and analysis. Previously, spectroreflectometer data recorded on strip charts.

Hurd, William A.↗

Sizing Dye-Penetrant Indications Of Defects

Sizes of cracks and holes viewed through borescope measured. Reference chart makes it possible to estimate sizes of borescope-observed defects on inner walls of tubes or otherwise hidden. Used both for round defects like pits or pores and for elongated ones like cracks.

Molina, Orlando G.↗

Communication satellite technology trends

A chronology of space-Earth interconnectivity is presented. The Advanced Communications Technology Satellite (ACTS) system, Land Mobile Satellite, space-Earth antennas, impact of antenna size on coverage, intersatellite links are outlined. This presentation is represented by graphs and charts only.

Cuccia, Louis↗

Space Assembly, Maintenance, and Servicing Study (SAMSS)

The goal is to define and establish Space Assembly, Maintenance, and Servicing (SAMS) capabilities to meet requirements for improved space systems. Consolidated requirements, hardware/tool concepts, systems analysis, related studies interaction, and schedule/milestones are outlined. This presentation is represented by charts and figures only.

Wong, Joseph↗

Telerobotics

This presentation summarizes NASA's future plans and current technology programs for telerobotics and is represented by charts.

Pivirotto, Donna L.↗

Space station assembly/servicing capabilities

The aim is to place a permanently manned space station on-orbit around the Earth, which is international in scope. The program is nearing the close of the system definition and preliminary design phase. The first shuttle launch for space station assembly on-orbit is estimated for January 1993. Topics perceived to be important to on-orbit assembly and servicing are discussed. This presentation is represented by charts.

Joyce, Joseph↗

Overview of crew member energy expenditure during Shuttle Flight 61-8 EASE/ACCESS task performance

The energy expenditure of the Shuttle Flight 61-B crewmembers during the extravehicular performance of Experimental Assembly of Structures in EVA (EASE) and Assembly Concept of Construction of Space Structures (ACCESS) construction system tasks are reported. These data consist of metabolic rate time profiles correlated with specific EASE and ACCESS tasks and crew comments. Average extravehicular activity metabolic rates are computed and compared with those reported from previous Apollo, Shylab, and Shuttle flights. These data reflect total energy expenditure and not that of individual muscle groups such as hand and forearm. When correlated with specific EVA tasks and subtasks, the metabolic profile data is expected to be useful in planning future EVA protocols. For example, after experiencing high work rates and apparent overheating during some Gemini EVAs, it was found useful to carefully monitor work rates in subsequent flights to assess the adequacy of cooling garments and as an aid to preplanning EVA procedures. This presentation is represented by graphs and charts.

Horrigan, D. J.↗

Pinhole occulter experiment

Viewgraphs and charts from a briefing summarize the accomplishments, results, conclusions, and recommendations of a feasibility study using the Pinhole Occulter Facility (POF). Accomplishments for 1986 include: (1) improved IPS Gimbal Model; (2) improved Crew Motion Disturbance Model; (3) use of existing shuttle on-orbit simulation to study the effects of orbiter attitude deadband size on POF performance; (4) increased understanding of maximum performance expected from current actuator/sensor set; (5) use of TREETOPS nonlinear time domain program to obtain system dynamics describing the complex multibody flexible structures; (6) use of HONEY-X design tool to design and evaluate multivariable compensator for stability, robustness, and performance; (7) application of state-of-the-art compensator design methodology Linear Quadratic Gaussian/Loop Transfer Recovery (LQG/LTR); and (8) examination of tolerance required on knowledge of the POF boom flexible mode frequencies to insure stability, using structure uncertainty analysis.

Ring, Jeff↗

Inerting and atmospheres

It is argued that fires are dependent primarily on the concentration of oxygen, whereas life is dependent on the partial pressure of oxygen. It follows that in an inhabited capsule it should be possible to exercise a certain amount of willful control over fire and still maintain habitability by proper selection of the composition of the atmosphere. This leads to two concepts in the control of fires in confined spaces by controlling atmospheric composition: the first, to lower the overall potential hazard by maintaining the percent of oxygen in the capsule below that of air, and second, to provide for the emergency extinguishment of a fire by sudden flooding with nitrogen. Several relevant charts and graphs are presented.

Carhart, Homer W.↗

Dobson-stations performance assessment using TOMS data

Examples of comparisons of monthly summaries (based on daily measurements) of some of the regularily operating Dobson stations, with the values deduced from the Total Ozone Mapping Spectrometer (TOMS) overpass are given. Shortcomings in certain Dobson stations are identified, such as: use of an incorrect value for the extraterrestrial constant (HOBART); sudden large volume changes (Brisbane); unusually low Dobson readings (Mauna Loa); and use of inaccurate cloud blue sky charts, causing fictitious differences with direct sun measurements (Toronto).

Bojkov, Rumen D.↗

Orbital transfer vehicle studies overview

An overview is given in viewgraph form of orbital transfer vehicle concept definition and systems analysis studies. Project development flow charts are shown for key milestones from 1985 until 1997. Diagrams of vehicles are given. Information is presented in outline form on technology requirements, cooling of propellant tanks, cryogenic fluid management, quick connect/disconnect fluid interfaces and propellant mass transfer.

Perkinson, Don↗

Zero-G thermodynamic vent system for shuttle/Centaur

Viewgraphs are presented showing drawings of Centaur configurations, the Thermodynamic Vent System (TVS), the mixer pump, and the hydrogen vent motor pump inverter. A cryogenic performance summary is given in chart form. The TVS liquid flow operation and vapor flow operation are diagrammed.

Niggemann, Richard E.↗

Space bioreactor: Design/process flow

The design of the space bioreactor stems from three considerations. First, and foremost, it must sustain cells in microgravity. Closely related is the ability to take advantage of the weightlessness and microgravity. Lastly, it should fit into a bioprocess. The design of the space bioreactor is described in view of these considerations. A flow chart of the bioreactor is presented and discussed.

Cross, John H.↗