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Quantitative microprobe analysis of segregated particles in aluminum MIG /Metal Inert Gas/ and TIG /Tungsten Inert Gas/ welds indicated that there were about ten different kinds of particles, corresponding to ten different intermetallic compounds. Differences between MIG and TIG welds related to the individual cooling rates of these welds.
The research describes the sleep disturbing effects of jet aircraft flyover noise as it occurs at different times during the night. The results indicate that individuals respond statistically more, in terms of greater cortical desynchronization, during the first and last thirds of the night. During the middle third, while there is still a significant amount of cortical desynchronization in response to the jet aircraft noise, this is always less than that which occurs earlier or later in the night. The implications of this data are that it might be possible to reduce the disruptive effects of at least certain extrinsic sonic stimulation by appropriate scheduling.
A multichannel scanning device may fail to observe objects because of obstructions blocking the view, or different categories of objects may make up a resolution element giving rise to a single observation. Ground truth will be required on any such categories of objects in order to estimate their expected proportions associated with various classes represented in the remote sensing data. Considering the classes to be distributed as multivariate normal with different mean vectors and common covariance, maximum likelihood estimates are given for the expected proportions of objects associated with different classes, using the Bayes procedure for classification of individuals obtained from these classes. An approximate solution for simultaneous confidence intervals on these proportions is given, and thereby a sample-size needed to achieve a desired amount of accuracy for the estimates is determined.
The methods of powder and monocrystal X-ray diffraction served in identifying the mineral composition of gross samples of regolith from different levels of the drill core and about 80 individual regolith particles returned by the Luna 16 station. It was established that the Sea of Fertility regolith includes pyroxenes of the augite-pigeonite series, anorthites, ilmenite, olivines, spinels, alpha cristobalite, iron particles, glass, and several as yet unidentified particles. Crystallographic and roentgenometric data are given for all the lunar minerals found.
Characteristics of lunar soil are examined. The paper includes topics such as lunar soil genesis, particle types, grain size distribution, grain shape distribution, specific gravity, minimum and maximum density, and relative density. Lunar soil, consisting of complex mixtures of mineral fragments, miscellaneous glasses, agglutinates, and lithic fragments, is produced primarily by meteorite impacts. The grain size distributions for soils exposed to meteorite reworking for 100 million yr or more are classified as well-graded silty sands and sandy silts. The specific gravity of submillimeter lunar soil samples varies from 2.9 to 3.24 and individual particles range from 1.0 to greater than 3.32. Differences in specific gravity, intragranular porosity, particle shape, surface texture, and grain arrangements result in wide ranges in minimum and maximum densities. Meteorite impacts cause in situ lunar soil to have a low relative density at the surface which increases rapidly to a very high relative density at depths greater than 10 cm to 20 cm.
Spectral diagrams, illustrating the spectral characteristics of different water types, were constructed by means of simple statistical analysis of the various reflectance properties of water areas in Southern Scandinavia as registered by LANDSAT-1. There were indications that water whose spectral reproduction is dominated by chlorophyllous matter (phytoplankton) can be distinguished from water dominated by nonchlorophyllous matter. Differences between lakes, as well as the patchiness of individual lakes, concerning secchi disc transparency could be visualized after classification and reproduction in black and white and in color by means of line printer, calcomp plotter (CRT), and ink jet plotter respectively.
A large number of electrochemical concentration cell (EDD) ozonesondes were calibrated relative to ultraviolet photometric absorption (254 nm) to determine their precision and accuracy. The average agreement with UV photometry was found to be good, but with considerable variation from one ECC ozonesonde to another. Applying individual calibrations to vertical ozone profiles reduced the systematic differences between ECC ozonesonde total ozone values and Dobson spectrophotometric determinations of the same quantity, but did not improve random differences.
Direct photography of gaseous nebulae using interference filters to isolate individual emission lines is capable both of discriminating between different ions and of enhancing the visibility of nebulae by suppressing stellar images and the quasi-continuous sky background in favor of the chosen band pass. The instrumentation used in an examination of the ionization structure of emission nebulae and of the galactic plane in general, is described, as well as the characteristics of the prints obtained. Reasonable exposure times were obtained with the use of an image intensifier and five interference filters isolated the band passes chosen for the survey. A rough map of each field is presented with a print from the Becvar Skalnate Pleso covering the same area. The structural differences which the authors hoped to record can be seen in many of the fields included in this volume. For purposes of illustration, they are strikingly shown in the fields centered about the following "new" galactic coordinates, where l is longitude and b is latitude: I = 138 °, b = 0°; l = 293 °, b = 0°; and l = 263 °, b = 0 °. In addition to investigating the structure of known emission nebulae, the authors also hoped to find some new objects. By far the most striking of such discoveries is the new supernova remnant in the field l= 65.5 °, b = +5 °.
Far-infrared (lambda/bar/ = 37 to 108 microns) observations of 13 planetary nebulae are presented. Their far-infrared spectral energy distributions are in general similar to that of NGC 7027, the only planetary heretofore observed at these wavelengths. Characteristic dust temperatures are near 100 K. The one planetary with a far-infrared spectral energy distribution significantly different from that of NGC 7027 is IC 418. Relative dust masses have been computed for the nebulae, and, within the very large errors, no signifcant differences are found between the masses of dust in individual nebulae. The one exception is, again, IC 418, which may have a significantly lower dust mass than the other nebulae. Emission optical depths are computed and appear to be roughly correlated with the nebular electron density.
Several low Ni-iron meteorites previously classified with group IAB are reclassified with group IIICD because of lower Ge, Ga, W, and Ir concentrations and higher As concentrations. The low Ni extreme of IIICD is now 62 mg/g, and that of IAB is 64 mg/g. It is proposed that the meteorites of both groups formed as individual shock melts on a chondritic parent body. The differences in log element-log Ni slopes of the daughter irons demonstrate that there were detailed differences in the composition and size of phases in the parental material (e.g., more Ni in the sulfides or metal of IAB, or more Ge and Ir in the oxides of IIICD).
Three computer quantitative techniques for determining urban land cover patterns are evaluated. The techniques examined deal with the selection of training samples by an automated process, the overlaying of two scenes from different seasons of the year, and the use of individual pixels as training points. Evaluation is based on the number and type of land cover classes generated and the marks obtained from an accuracy test. New Orleans, Louisiana and its environs form the study area.
A simple topographic slope correction using a linearized thermal model and assuming slopes less than about 20 degrees is presented. The correction can be used to analyzed individual thermal images or composite products such as temperature difference or thermal inertia. Simple curves are provided for latitudes of 30 and 50 degrees. The form is easily adapted for analysis of HCMM images using the DMA digital terrain data.
In an effort to constrain the tectonic history and mechanical properties of the lithosphere in the Elysium province, the stress fields predicted by different models are compared to the observed tectonic features of the region. The models are all products of volcanic loading of the Martian lithosphere, but at three different scales: global (Tharsis), regional (Elysium Planitia), and local (individual shields). Conclusions: The concentric graben surrounding Elysium Mons can be ascribed to the flexural response of an approximately 50-km-thick elastic lithosphere to loading by the volcano. No tectonic evidence for the support of larger-scale Elysium Planitia volcanic units by lithospheric flexure. The quasi-global loading of the Tharsis rise appears to have produced identifiable tectonic effects in the Elysium region.
Measurements of the neutral wind in the polar F region from Dynamics Explorer-2 (DE-2) were used to illustrate asymmetries in the neutral circulation that are dependent on the sign of the B sub y component of the interplanetary magnetic field (IMF). Individual DE-2 orbits and averaged data sets from different Universal times are presented. The data are categorized according to the sign of the hourly averaged IMF B sub y component measured by ISEE-3 for the hour preceding the DE-2 measurement. The major features observed are: (1) an asymmetry in the polar cap neutral flow velocity with the region of most rapid antisunward flow shifting from the dawn side to the dusk side of the polar cap as B sub y changes from positive to negative; (2) a shift in magnetic local time of the region of entry of neutral gas into the polar cap from a location on the dawn side of the noon-midnight meridian for B sub y positive to one more biased towards the dusk side for B sub y negative; (3) an enhancement in the velocities associated with the dawn, anti-clockwise neutral vortex B suby y negative relative to those observed for B sub y positive. The B sub y neutral wind asymmetries can be explained by similar asymmetries, previously observed, in the polar ion convection pattern. They imply a direct causal relationship between solar wind/magnetosphere coupling and neutral thermospheric dynamics.
Methods for studying star formation are reviewed. Stellar clusters and associations, as well as field stars, provide a fossil record of the star formation process. Regions of current star formation provide a series of snapshots of different epochs of star formation. A simplified picture of individual star formation as it was envisioned in the late 1970s is contrasted with the results of recent observations, in particular the outflow phenomenon.
The theoretical model of Lee and Wang (1986) for the instability of an annular jet, in which the jet's liquid layer is treated as a thin liquid sheet, is examined. It is suggested that the model should be altered so that when the envelope is closing its bottleneck during collapse, the new envelope experiences a sharp pressure pulse from its gaseous core, reversing the normal velocity of the sheet enough to maintain continuous constant gas flow. Using this improved version of the model, it is shown that if the liquid velocity is high enough and the gas velocity is greater than the liquid velocity, the bubble-formation frequency varies linearly with the difference between the two velocities, but not with their individual values.
A process for development of clean silicon carbide fiber with a small diameter and high reliability is presented. An experimental evaluation of operating conditions for SiC fibers of good mechanical properties and devising an efficient technique which will prevent welding together of individual filaments are discussed. The thermodynamic analysis of a different precursor system was analyzed vigorously. Thermodynamically optimum conditions for stoichiometric SiC deposit were obtained.
System-level ASPEN models were developed for the CO2 partial reduction subsystem and a bioregenerative life support subsystem (BRLSS). The individual component and subsystem models were integrated into three different system-level atmospheric revitalization subsystem (ARS) models: baseline physico-chemical, BRLSS, and partial reduction of Martian CO2. The Aspen models were based on FORTRAN interfaces necessary for integration with another program, G189A, to perform quasi-transient modeling. Detailed reactor models were prepared for the two CO2 reduction reactors (Bosch and Advanced Carbon Formation), and the low-temperature trace contaminant oxidation reactor.