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At least 721 records · Page 40

Apollo 16 geochemical X-ray fluorescence experiment: Preliminary report

The lunar surface was mapped with respect to Mg, Al, and Si, as Al/Si and Mg/Si ratios along the projected ground tracks swept out by the orbiting Apollo 16 spacecraft. The results confirm the observations made during the Apollo 15 flight and provide data for a number of features not covered before. The data are consistent with the idea that the moon has a widespread differentiated crust (the highlands). The Al/Si and Mg/Si chemical ratios correspond to that for anorthositic gabbro through gabbroic anorthosites or feldspathic basalts. The X-ray results suggest the occurrence of this premare crust or material similar to it as the Descartes landing site.

Adler, I.↗

Apollo 16 geochemical X-ray fluorescene experiment: Preliminary report

The lunar surface was mapped with respect to Mg, Al and Si as Al/Si and Mg/Si ratios along the projected ground tracks swept out by the orbiting Apollo 16 spacecraft. The results confirm the observations made during the Apollo 15 flight and provide data for a number of features not covered before. The data are consistent with the idea that the moon has a widespread differentiated crust (the highlands). The Al/Si and Mg/Si chemical ratios correspond to those for anorthositic gabbro through gabbroic anorthosites or feldspathic basalts. The X-ray results suggest the occurrence of this premare crust, or material similar to it, at the Descartes landing site.

Adler, I.↗

Observations of proton spectra (1.0 less than or equal to proton energy less than or equal to 300 keV) and pitch angle distributions at the plasmapause

Detailed proton spectral and pitch angle distribution observations were obtained from two proton detectors and a fluxgate magnetometer flown on Small Scientific Satellite A (Explorer 45). The data of interest are from orbit 99 in-bound occurring on 17 December 1971, some 8 hours prior to the sudden commencement of a magnetic storm. The data are consistent with the initiation of ion cyclotron instability when certain requirements are met. These criteria are met initially at the altitude at which the sudden intensity decrease occurs. However, after the initiation of the instability, the linear theory is unable to explain the further evolution of intensities, pitch angle distributions, and energy spectra of the ring current particles.

Williams, D. J.↗

Hydrogen-enhanced fatigue crack growth in Ti-6Al-4V ELI weldments.

The effects of a hydrogen environment on the fatigue crack growth rates in Ti-6Al-4V ELI (STA) and weld material were determined in the temperature range of ambient to -200 F. The hydrogen environment resulted in an acceleration of the crack growth rate and a change in the fracture mode for both materials in the temperature range of ambient to -100 F. At -200 F, there was no significant difference between the crack growth rates obtained in helium and hydrogen gas. The degree of hydrogen-enhanced crack growth was found to be dependent on the crack tip stress-intensity range, temperature, and microstructure of the material. The data are consistent with an embrittlement mechanism involving hydrogen diffusing ahead of the crack front.

Pittinato, G. F.↗

Rocket-based vector magnetic measurements of Sq ionospheric currents near sporadic E.

A rocket-borne vector magnetometer has been used to infer the current magnitude, direction, and distribution of midlatitude ionospheric currents near sporadic E. Complete vector information returned throughout the flight indicates that a southward equivalent surface current (vertically integrated current) of 0.15 amp/m was encountered between the altitudes of 104 and 118 km in both ascending and descending portions of the flight. Vertical distribution of the current within the layer was approximately uniform, and the layer was found to be horizontal within the accuracy of the experiment. The data are consistent with the assumption that a sporadic-E layer observed by Wallops Island ionosondes significantly altered the usual Sq current flow pattern by concentrating the current into a narrow altitude range, and by horizontally focusing the current flow into the sporadic-E region with attendant reduction of current density outside the region.

Cloutier, P. A.↗

Thermodynamic properties of liquid metals /A review/.

Summary of the current state of knowledge about the thermodynamic properties of liquid metals, including heats of fusion and heat capacities. A table is presented of consistent thermodynamic data for liquid metals, including estimates for the many high-melting transition metals which have not yet been studied, based on new levitation data and on periodic table correlations.

Margrave, J. L.↗

Material injection alleviation and plasma diagnostic measurements during the RAM C-III flight.

The results of a material injection RF blackout alleviation experiment and of plasma diagnostic measurements using electrostatic probes and an S-band reflectometer in a 25,000 ft/sec reentry flight are presented. Significant alleviation of RF blackout is observed at altitudes of from 270,000 feet to 120,000 feet due to injection of water and Freon E-3 on VHF, S-band, C-band, and X-band frequencies. Electrostatic probe data, attenuation data, and S-band diagnostic data show consistent plasma results. The relative effectiveness of water and Freon E-3 is discussed.

Schroeder, L. C.↗

Apollo 16 geochemical X-ray fluorescence experiment - Preliminary report.

Mapping of the lunar surface with respect to magnesium, aluminum, and silicon as aluminum/silicon and magnesium/silicon intensity ratios along the projected ground tracks swept out by the orbiting Apollo 16 spacecraft. The results confirm the observations made during the Apollo 15 flight and provide new data for a number of features not covered before. The data are consistent with the idea that the moon has a widespread differentiated crust (the highlands). The aluminum/silicon and magnesium/silicon concentration ratios correspond to those for anorthositic gabbros through gabbroic anorthosites or feldspathic basalts. The X-ray results suggest the occurrence of this premare crust or material similar to it at the Descartes landing site.

Adler, I.↗

Cosmic gamma-rays from pion decay

The production of gamma rays from the decay of neutral pions produced in interstellar cosmic ray interactions was studied, limited to the total gamma ray intensity. Using the upper-limit gamma ray production, an upper-limit is obtained consistent with that obtained by Kraushaar. It is shown that whatever the shape of the gamma ray spectrum, the normalization has to be consistent with data of the total cross sections.

Stecker, F. W.↗

Task 10: an ERTS Experiment for Mapping Iron Compounds, 1383

The author has identified the following significant results. Preliminary results of a spectral ratioing technique are shown for a region at the southern end of the Wind River Range, Wyoming. Digital ratio graymaps and analog ratio images have been produced for the test site, but ground truth is not yet available for thorough interpretation of these products. ERTS-1 analog ratio images were found generally better than either ERTS-1 single channel images or high altitude aerial photos for the discrimination of vegetation from non-vegetation in the test site region. Some linear geological features smaller than the ERTS-1 spatial resolution are seen as well in ERTS-1 ratio and single channel images as in high altitude aerial photography. Geochemical information appears to be extractable from ERTS-1 data. Good preliminary quantitative agreement between ERTS-1 derived ratios and laboratory derived reflectance ratios of rocks and minerals encourage plans to use lab data as training sets for a simple ratio gating logic approach to automatic recognition maps. Empirical atmospheric corrections indicate that atmospheric corrections are needed to make the ratio method, and possibly other types of data processing, consistent over large geographical and temporal displacements.

Vincent, R. K.↗

Results on the energy dependence of cosmic ray charge composition

Measurements using a balloon-borne ionization spectrometer on the differential energy spectra of the heavy nuclei of the galactic cosmic radiation are reported. The spectra of individual elements up to oxygen and groups of nuclei up through iron were measured up to almost 100 GeV/nucleon. The energy spectrum of the secondary nuclei, B+N, is steeper than that of the primary nuclei, C+O, by gamma = 0.21 + or - .09 in agreement with other authors. The spectral shapes found are reasonably well represented by single power laws between 2 and 60 GeV/nucleon. Data are consistent with the decrease in the secondary to primary ratio found by others above 20 GeV/nucleon, but it shows no evidence for any sudden change in this ratio within counting statistics. The most dramatic finding is that the spectrum of the iron nuclei is flatter than that of the carbon and oxygen nuclei by 0.57 + or - 0.14 of a power. The experimental techniques for charge and energy determination are presented and corrections due to nuclear disintegration and losses of energy out the bottom of the spectrometer are discussed.

Balasubrahmanyan, V. K.↗

Observations of noise bands associated with the upper hybrid resonance by the Imp 6 radio astronomy experiment.

The intense noise bands occurring near the upper hybrid resonance frequency have been observed with the Imp 6 GSFC radio astronomy experiment in the plasmasphere. The identification of the upper hybrid resonance provides an accurate measure of the local electron density and allows the observed noise data to be fit to the scale of characteristic frequencies in the plasma. The data are consistent with earlier theoretical interpretations in which noise is generated between the upper hybrid and plasma frequencies and propagates to region 4 of the CMA diagram, where it is reflected at the L = 0 plasma cutoff.

Mosier, S. R.↗

Dual-frequency bistatic-radar investigations of the moon with Apollos 14 and 15.

Simultaneous 13- and 116-cm wavelength radio transmissions from the Apollo 14 and 15 spacecraft were received on the earth after reflection from the lunar surface. The received data were processed to obtain complete polarization and power spectra of the echo signal; the ellipticity, orientation, and magnitude of the deterministically polarized part were obtained as a function of frequency. The polarized parts of the echo spectra were then reduced according to the theory of quasi-specular scattering from a gently undulating surface. The unpolarized portions of the echo spectra were associated with a diffuse scattering mechanism. Within Mare Serenitatis and Oceanus Procellarum, the 13-cm data follow a classical Fresnel reflection curve corresponding to relative dielectric constant epsilon = 3.1 plus or minus 0.1. Over most of these same areas, the 116-cm data are consistent with this value of relative dielectric constant. In some areas, however, notably between Reiner and Hevelius, there are marked deviations from the reflectivities predicted for epsilon = 3.1. These results cannot be explained on the basis of simple models employing contiguous, semiinfinite, dielectric interfaces.

Tyler, G. L.↗

Environmental application of remote sensing methods to coastal zone land use and marine resource management. Appendix F: User's guide for advection, convection prototype

A user's manual is provided for the environmental computer model proposed for the Richmond-Cape Henry Environmental Laboratory (RICHEL) application project for coastal zone land use investigations and marine resources management. The model was developed around the hydrologic cycle and includes two data bases consisting of climate and land use variables. The main program is described, along with control parameters to be set and pertinent subroutines.

Source record↗

Vibrational relaxation of carbon monoxide studied by two-wavelength infrared emission

Experimental results are presented for the vibrational relaxation of pure carbon monoxide behind incident shock waves over the temperature range 4000 to 6300 K. The data were obtained as infrared emission from the fundamental and overtone vibrational band systems (in some of the experiments the two-band systems were recorded simultaneously). The data are consistent with present theories for the vibrational relaxation of diatomic molecules and can be interpreted in terms of an initial Boltzmann vibrational distribution relaxing toward final equilibrium via a continuous sequence of intermediate Boltzmann distributions.

Chackerian, C., Jr.↗

Trapped solar and cosmogenic noble gas abundances in Apollo 15 and 16 deep drill samples

Abundances and isotopic compositions of all the stable noble gases (He, Ne, Ar, Kr, Xe) were measured at different depths of the Apollo 15 and Apollo 16 deep drill cores, and in several surface fines and breccias. All samples analyzed from both drill cores were found to contain large concentrations of solar wind implanted gases. This means that even the deepest layers of both cores have experienced a lunar surface history. The Apollo 15 core data are consistent with a combined accretion plus static time of a few hundred million years, and also indicate variable pre-accretion irradiation of core material. Depth profiles of cosmogenic gases in the Apollo 16 core show considerably larger concentrations of cosmic gases below 65 cm depth than above. This pattern may be interpreted either as an accretionary process, or by a more recent deposition of regolith to the upper 70 cm of the core.

Bogard, D. D.↗

Electric and magnetic fields measured during a sudden impulse

The electric field in the ionosphere and the magnetic field at the earth's surface in the mid-latitude region were both measured during a sudden impulse. Ionospheric conductivities deduced from this data were consistent with expectations, thus suggesting that the fluctuations in the magnetic field at the earth's surface were caused by overhead ionospheric currents that were driven by an electric field associated with the sudden impulse.

Schutz, S.↗

OSO-7 observations of a high-latitude X-ray source associated with Abell cluster A2052

An X-ray source with a flux of 1.6 times 10 to the -10th power ergs per sec/sq cm (2-10 keV) has been observed at high galactic latitude by the MIT X-ray detectors on the OSO-7 satellite. Designated GX 8+50, its position is 15 hr 14.2 min right ascension, 6 deg 51 min declination, with a 90 percent confidence error circle of area 0.5 sq deg. The data are consistent with a power-law spectrum with an exponent 1.2 (plus or minus 0.2) or a thermal-bremsstrahlung spectrum with kT = 4 plus or minus 1 keV. A likely identification is the Abell cluster A2052, whose center coincides with the radio source 3C 317.

Heinz, C. J.↗