The relation between low-latitude neutral density variations near 400 km and magnetic activity indices
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Anderson, A. D.↗
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On the use of Godhavn H-component as an indicator of the interplanetary sector polarity
An objective method of inferring the polarity of the interplanetary magnetic field using the H-component at Godhavn is presented. The objectively inferred polarities are compared with a subjective index inferred earlier. It is concluded that no significant difference exists between the two methods. The inferred polarities derived from Godhavn H is biased by the (slp) sub q signature in the sense that during summer prolonged intervals of geomagnetic calm will result in inferred Away polarity regardless of the actual sector polarity. This bias does not significantly alter the large scale structure of the inferred sector structure.
Svalgaard, L.↗
Morphological and cytochemical indices of the stress reaction in the blood system under the influence of G-forces
G-forces cause morphological and cytochemical changes characteristic of the stress reaction. The cytochemical changes in RNA content on lymphocytes, glycogen, and activity of oxidative enzymes in granulocytes are phasal in nature.
Yurina, N. A.↗
Biological indicators for monitoring water quality of MTF canals system
Biological models, diversity indexes, were developed to predict environmental effects of NASA's Mississippi test facility (MTF) chemical operations on canal systems in the area. To predict the effects on local streams, a physical model of unpolluted streams was established. The model is fed by artesian well water free of background levels of pollutants. The species diversity and biota composition of unpolluted MTF stream was determined; resulting information will be used to form baseline data for future comparisons. Biological modeling was accomplished by adding controlled quantities or kinds of chemical pollutants and evaluating the effects of these chemicals on the biological life of the stream.
Sethi, S. L.↗
The oxidation state of europium as an indicator of oxygen fugacity
Empirical oxygen barometers based on Eu(2+)/Eu(3+) ratios in plagioclase feldspar and magmatic liquid were developed using Philpott's (1970) approach and the experimental data of Drake (1972). Oxygen fugacities calculated on the basis of Eu(2+)/Eu(3+) ratios for terrestrial basalts cluster tightly around 10 to the negative seventh power. Oxygen fugacities for Apollo 11 and 12 lunar ferrobasalts cluster tightly around 10 to the negative 12.7 power. Calculated oxygen fugacities for achondritic meteorites are lower than for lunar samples by several orders of magnitude.
Drake, M. J.↗
Thresholds for the perception of angular acceleration as indicated by the oculogyral illusion
A motorized chair (with precise servo controls) accelerated the observer in a clockwise (CW) or counterclockwise (CCW) direction at rates that ranged in logarithmic progression from 0.02 to 6.00 deg/sq sec. The target, a narrow collimated line of light, was contained within a goggle device worn by the observer and therefore fixed in relative position to him. The illusion, appearing as rightward or leftward movement of the visual target in the direction of acceleration, was determined by a double staircase procedure among 300 normal and 4 labyrinthine-defective observers. None of the latter perceived the illusion. The majority of normal observers revealed no substantial directional difference (CW vs. CCW threshold). Threshold frequency distributions ranged in rate (deg/sq sec) from 0.020 to 0.950; the threshold of response in more than half the normal observers was less than 0.10, in over three-fourths was less than 0.20, in over 90% less than 0.30, and 100% less than 1.00.
Miller, E. F., II↗
Digital adaptive flight control design using single stage model following indices
Simple mechanical linkages are often unable to cope with many control problems associated with high-performance aircraft. This has led to the development of digital fly-by-wire control systems and in particular digital adaptive controllers that can be efficiently adjusted during system operation. To this effect, a control law has been derived based upon the minimization of a single-stage weighted combination of control energy and the squared error between the states of a linear plant and model. This control logic is interfaced with an on-line weighted least-squares estimator and a Kalman state filter. The utility of the resultant control system is illustrated by its application to the linearized dynamics of a typical fighter aircraft.
Alag, G.↗
On the use of Godhavn H component as an indicator of the interplanetary sector polarity
An objective method of inferring the polarity of the interplanetary magnetic field using the H component at Godhavn is presented. The objectively inferred polarities are compared with a subjective index inferred earlier (Svalgaard, 1972b). It is concluded that no significant difference exists between the two methods. The inferred polarities derived from Godhavn H are biased by the Sq-p signature in the sense that during summer, prolonged intervals of geomagnetic calm will result in inferred away polarity regardless of the actual sector polarity. This bias does not significantly alter the large-scale structure of the inferred sector structure.
Svalgaard, L.↗
Problems in the interpretation of lunar mare stratigraphy and relative ages indicated by ejecta from small impact craters
The numbers of large ejecta blocks in excess of several meters in diameter ('blockiness') around the rims of small craters in southeastern Mare Serenitatis exceed those around similar craters in southern Mare Imbrium (and some other regions) at all but the final stages of crater degradation. Terrestrial explosion crater analogs, studies of impact processes, and a layered mare model suggest that the nature of the layering in the subsurface, including lavas, ejecta and buried regolith horizons, could account for the variable blockiness of crater ejecta and, possibly, for some variation in crater size-frequency distributions. Such effects would limit the reliability and utility of counting postmare craters for the purpose of estimating the relative ages of mare surfaces. Similarly, comparisons of the effects of progressive degradation on small impact craters to determine relative or absolute ages of individual craters may be limited by the influence of stratigraphy on ejecta fragment size distributions, which would in turn affect micrometeorite erosion rates and regolith production models.
Young, R. A.↗
On the color indices of giants and subgiants in globular clusters
The globular-cluster metal-abundance parameter, which is the intrinsic color index at the intersection of the horizontal and subgiant branch in the color-magnitude diagram, is shown to be tightly correlated with the concentration ratio of Fe/H.
Butler, D.↗
Continuous HCl in air indicator
Steady stream of air is drawn into system and passes between light source and photocell. Incoming gases are sprayed with ammonia forming white cloud of NH4Cl if any HCl is present.
Bartera, R. E.↗
Indicated mean-effective pressure instrument
Device is capable of measuring and calculating IMEP of internal combustion engines in real time. Apparatus is used to provide mass flow measurements in engine cylinder and in measurement of release energy of nonlinear spring.
Rice, W. J.↗
Vector plotting as an indication of the approach to flutter
A binary flexure-torsion analysis was made to check theoretically a method for predicting flutter which depends on plotting vectorially the amplitudes of response relative to the exciting force and extracting the relevant damping rate. The results of this calculation are given in graphs both of the vector plots themselves and of the estimated damping rate against forward speed. The estimated damping rates are compared with calculated values. The method has the advantage that in a flight flutter test damping can be estimated from continuous excitation records: the method is an extension of the Kennedy and Pancu technique used in ground resonance testing.
Broadbent, E. G.↗
Cloud-top parameters - A hail indicator
Airborne photographic observations of four hail-producing storms are discussed. With the exception of one storm producing a tornadic event, the overshooting tops were nearly steady-state. The tops were consistently high and wide, reaching maximum heights within about 5 minutes of the initiation of hail. Measured updraft velocities in the turrets composing the overshooting top were 25 m/sec. The dimensions of the overshooting tops were sufficiently large to permit satellite observation.
Pearl, E. W.↗
Compatibility of meteorological rocketsonde data as indicated by international comparison tests
Results of two experiments involving intercomparisons of rocketsonde measurements of temperature and wind data in the 25 to 80 km altitude region in the CIMO (Commission for Instruments and Methods of Observations) program during September 1973 are reported. Rocketsonde systems used by France, the USSR, the UK, the U.S., and Japan in the two parts of the program (one series of tests at Wallops Island, Va., the other in French Guiana) are described. Wind data were derived from radar tracking of retardation devices and payloads in descent. Day and night temperature differences were examined. The intercomparisons revealed excellent compatibility of the rocketsonde data up to 60 km in wind observations. Some outstanding problems are pointed out.
Finger, F. G.↗
Lake eutrophication as indicated by ERTS satellite imagery
Light reflectance from water in the laboratory always correlates to the water quality parameter of turbidity. This turbidity is caused by suspended solids in the water and for a particular type of material there is a good correlation between the weight of these suspended solids and turbidity. However, this correlation is different for different types of material. When this suspended material is living green matter as in an eutrophic lake, the changes in reflectance can be detected as changes in brightness on a particular aerial image. Two test sites have shown that there is indeed a good correlation between the brightness on an ERTS image and lake eutrophication.
Scherz, J. P.↗
Logic-state-change indicator and frequency doubler
Low-power TTL circuit produces an output pulse whenever logic level at its input terminal changes. Circuit can also be used for doubling square-wave frequency.
Hudgins, J. I.↗
Angle-indicating digital servo
Device determines position of capacitive pickup relative to gravity-stabilized inductive element. Self nulling bridge with digital readout is faster and more accurate than electromechanical equivalent.
Parra, G. T.↗