The mass-radius relation for cold spheres of low mass
Mass and radius relations for zero temperature spheres of chemical elements, using equation of state and numerical integration
Salpeter, E. E.↗
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Results for “chemical elements”
Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.
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Neutron activation analysis of milligram quantities of Apollo 11 lunar rocks and soil
Apollo 11 lunar rocks and soil chemical elements analysis by neutron activation scheme
Kharkar, D. P.↗
Chemical composition of Apollo 14 soils 14163 and 14259
Apollo 14 lunar soils chemical element concentrations by atomic absorption spectrophotometry and isotope dilution
Nava, D. F.↗
Comparison of the analytical results from the Surveyor, Apollo, and Luna missions
Chemical element composition and mineralogy of powdered lunar surface material, comparing Surveyor, Apollo and Lunik missions data
Turkevich, A. L.↗
Average chemical composition of the lunar surface
The available data on the chemical composition of the lunar surface at eleven sites (3 Surveyor, 5 Apollo and 3 Luna) are used to estimate the amounts of principal chemical elements (those present in more than about 0.5% by atom) in average lunar surface material. The terrae of the moon differ from the maria in having much less iron and titanium and appreciably more aluminum and calcium.
Turkevich, A. L.↗
Instrument to measure energy and charge of low energy interplanetary particles
An experiment to measure the charge composition and energy spectra of ultra low energy charged particles in interplanetary space has been developed and launched on the IMP 8 (Explorer 50) satellite on Oct. 26, 1973. The instrument consists of two separate sensors sharing common electronics. One of these sensors uses a thin window gas proportional counter to measure the rate of energy loss and a totally depleted silicon surface barrier detector to measure total energy of incoming particles. The energy range for two dimensional analysis extends from 300 KeV to 2.5 MeV for protons and 60 KeV/nucleon to 25 MeV/nucleon for iron with excellent resolution of individual chemical elements. The other sensor combines electrostatic deflection with total energy measurements in silicon surface barrier detectors to give the ionic charge and kinetic energy of the particle.
Tums, E.↗
Effect of a progressive sound wave on the profiles of spectral lines. 2: Asymmetry of faint Fraunhofer lines
The absorption coefficient profile was calculated for lines of different chemical elements in a medium with progressive sound waves. Calculations show that (1) the degree and direction of asymmetry depend on the atomic ionization potential and the potential of lower level excitation of the individual line; (2) the degree of asymmetry of a line decreases from the center toward the limb of the solar disc; and (3) turbulent motions 'suppress' the asymmetry.
Kostyk, R. I.↗
Atmospheric aerosols: A literature summary of their physical characteristics and chemical composition
This report contains a summary of 199 recent references on the characterization of atmospheric aerosols with respect to their composition, sources, size distribution, and time changes, and with particular reference to the chemical elements measured by modern techniques, especially activation analysis.
Harris, F. S., Jr.↗
Quinoxaline polymers and copolymers derived from 1,4-bis(1'-naphthalenyloxalyl)benzene and their graphite composites
Experimental studies were performed with new polyquinoxalines and their graphite composites. Four polymers were synthesized, and then were characterized with respect to their inherent viscosity, elemental chemical analysis, mechanical, and thermodynamic properties. Structural formulas of the polymers and their precursors are given; methods of synthesis are described; and specifically examined was the preparation of polymers from 3,3' diamino-benzidine from 1,4- and 1,3- bis ((1'-napthalenyl) oxalyl) benzene respectively. Also considered was the preparation of polyquinoxalines from poly (p-benzil), and 1,2- aryldiamines.
Port, W. S.↗
Some wear studies on aircraft brake systems
An initial investigation of worn surfaces in friction pads and steel rotors used in current aircraft brakes was carried out using electron microprobe and X-ray diffraction analysis. It consists of the topographical study and the analysis of chemical element distribution. Based upon this initial examination, two approaches, microscopic and macroscopic have been conducted to interpret and formulate the wear mechanism of the aircraft brake materials. Microscopically, the wear particles were examined. The initiation and growth of surface cracks and the oxidation were emphasized in this investigation. Macroscopically, it has been found that, for the current copper based brake material sliding against 17-22 AS steel in a caliper brake, the surface temperature raised due to frictional heat is nonlinearly proportional to the load applied and slide time with speed at 1750 rpm. The wear of brake materials is then proportional to this temperature and is also a function of the melting temperature for copper.
Ho, T. L.↗
The Apollo 15 and 16 X-ray fluorescence experiment
An X-ray fluorescence spectrometer was flown aboard the Apollo 15 and 16 spacecrafts orbiting the moon. The X-ray instrument was used to produce a chemical map of that portion of the moon covered by the projected ground tracks and illuminated by the sun during the period of flight. The instrument includes three thin windowed proportional counters, two of which have selected X-ray filters. The field of view of the surface is determined by a collimator, while a detector on the opposite side of the spacecraft provides a continuous monitoring of the solar X-ray output. While the number of chemical elements determined was limited to Mg, Al, and Si, these proved to be very important diagnostic elements.
Adler, I.↗
New horizons for study of the cardiopulmonary and circulatory systems
The paper discusses the development of computer-controlled three-dimensional reconstruction techniques designed to determine the dynamic changes in the true shape and dimensions of the epi- and endocardial surfaces of the heart, along with variable time base (stop-action to real-time) displays of the transmural distribution of the coronary microcirculation and the three-dimensional anatomy of the macrovasculature in all regions of the body throughout individual cardiac and/or respiratory cycles. A technique for reconstructing a cross section of the heart from multiplanar videoroentgenograms is outlined. The capability of high spatial and high temporal resolution scanning videodensitometry makes possible measurement of the appearance, mean transit and clearance of roentgen opaque substances in three-dimensional space through the myocardium with a degree of simultaneous anatomic and temporal resolution not obtainable by current isotope techniques. The distribution of a variety of selected chemical elements or biologic materials within a body portion can also be determined.
Wood, E. H.↗
Mineral and nitrogen metabolic studies on Skylab flights and comparison with effects of earth long-term recumbency
A metabolic study of the effects of space flight on various chemical elements, particularly those with special relevance to the musculo-skeletal system, was carried out on the nine astronauts who participated in the three Skylab flights of 28, 59 and 84 days in 1973-1974. The study required of the cooperating crewmen constant dietary intake, continuous 24-hour urine collections and total fecal collections for 21-31 days before each flight, throughout each flight and for 17-18 days post-flight. Increases in urinary calcium and negative calcium balances during space flight were generally similar to those found in previous immobilization and bedrest studies. The persistence of these alterations in calcium metabolism throughout the flights suggested that calcium losses would continue in weightlessness for a very long time. Significant losses of nitrogen and phosphorus occurred, associated with observed reduction in muscle tissue. Both mineral and muscle losses occurred despite rigorous exercise regimens in flight. It was concluded that unless protective measures can be developed, capable musculo-skeletal function is likely to be impaired in space flights, ultimately to be conducted to Mars, of 1-1/2 to 3 years duration.
Whedon, G. D.↗
Differentiation of the matter of the moon
The following facts were uncovered in comparing the basaltic surface rocks of the moon with terrestrial tholeiitic basalts and ordinary chondrites: (1) there is an excess of the so-called refractory chemical elements, including the group of truly refractory elements, the rare earths, U, and Th, in comparison with their content in primitive terrestrial basalts and chondrites; (2) the so-called siderophilic elements have lower contents in the lunar surface rocks than in terrestrial rocks; (3) the low alkali content (Na, K, Rb) in lunar rocks is established; (4) there is a low content of H2O and the ordinary gases CO2, halides, etc.; (5) the low content of metals with high vapor pressure, (In, Tl, etc.) has been established. It is proposed that U and Th were carried from the internal areas to the peripheral rocks of the moon during magmatic activity, i.e., up to 3 billion years ago. This redistribution of U and Th lead to their concentration in surface layers of the moon, and the heat which they generated was lost into surrounding space. The conclusion is then reached that in order to understand processes on the moon, the chondritic model cannot be used.
Vinogradov, A. P.↗
Wear studies on aircraft brake materials
An investigation of both worn surfaces of friction pads and steel rotors which are being applied in current aircraft brakes has been carried out by employing an X-ray diffraction technique. It consists of the analysis of chemical element distribution in the surface layers. The wear particles were also examined by using the scanning electron microscope. The initiation and growth of surface cracks and the oxidation were emphasized in this investigation. A wear model was proposed for the current aircraft brake materials. Essentially this model proposed that cracks are formed in the surface layer of the brake material due to the normal and frictional stresses. It is primarily surface temperature dependent.
Ho, T. L.↗
Extraterrestrial materials processing and construction
Applications of available terrestrial skills to the gathering of lunar materials and the processing of raw lunar materials into industrial feed stock were investigated. The literature on lunar soils and rocks was reviewed and the chemical processes by which major oxides and chemical elements can be extracted were identified. The gathering of lunar soil by means of excavation equipment was studied in terms of terrestrial experience with strip mining operations on earth. The application of electrostatic benefication techniques was examined for use on the moon to minimize the quantity of materials requiring surface transport and to optimize the stream of raw materials to be transported off the moon for subsequent industrial use.
Criswell, D. R.↗
Lunar building materials: Some considerations on the use of inorganic polymers
The use of inorganic polymer systems synthesized from the available lunar chemical elements, viz., silicon, aluminum, and oxygen to make adhesives, binders, and sealants needed in the fabrication of lunar building materials and the assembly of structures is considered. Inorganic polymer systems, their background, status, and shortcomings, and the use of network polymers as a possible approach to synthesis are examined as well as glassy metals for unusual structural strength, and the use of cold-mold materials as well as foam-sintered lunar silicates for lightweight shielding and structural building materials.
Lee, S. M.↗
Glasses in the Luna 24 core and petrogenesis of ferrobasalts
Modal abundance and major- and minor-element chemical analysis of homogeneous, non-agglutinitic mare and non-mare glasses from the Luna 24 drill core show that most glasses can be related to known rock types. Mare glasses include: brown glass identical in composition to the fine-grained low-Mg VLT basalt; green glass which might be related to a coarser-grained ferrogabbro; a high-K green glass; and a high-Ti orange glass. Highland glass compositions include Highland basalt, gabbroic anorthosite, and pure anorthosite (i.e. plagioclase); minor Fra Mauro-type glass may also be present. It is apparent that fractional crystallization of some primitive basaltic magma occurred at Mare Crisium producing a chemically evolved ferrobasalt and related glasses. An early, high-Mg basin fill, as represented by the olivine vitrophyres, may be the parent magma. Subsequent near-surface fractionation produced a multiply-saturated liquid that finally erupted as the ferrobasalt flows sampled by Luna 24.
Norman, M.↗