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At least 1,297 records · Page 72
All sourcesNASA NTRSDOE OSTI
NASA NTRS1974

Origin of inert gases in 'rusty rock' 66095

The amount of trapped inert gases present in rock 66095, as well as the elemental and isotopic composition of these gases can be explained by 'contamination' of this rock - on the lunar surface - with as little as 0.2% of fines. There is no compelling evidence that these gases come from the impact of a comet or a carbonaceous meteorite on the moon, or that they represent genuine primordial lunar gas. The Ne-21 radiation age of 66095 is 1.1 plus or minus 0.5 m.y., which strongly suggests that this rock was excavated by the South Ray Crater event.

Heymann, D.↗
NASA NTRS1974

Measurement of multiplet intensities and noble gas-broadened line widths in the nu 3 fundamental of methane

Presented integrated intensity data at 300 K for J multiplets between P(11) and R(11) in the nu-3 fundamental of C-12 methane are shown to be in good agreement with most previously published pertinent values. Also, line widths measured at 100 K, 130 K, 190 K, 250 K, and 300 K for R(0), R(1), and R(2) broadened by He, Ne, and Ar are presented, and the line-width temperature dependence is discussed for the three cases of broadening.

Varanasi, P.↗
NASA NTRS1974

Absorption of laser radiation in a H-He plasma. I - Theoretical calculation of the absorption coefficient

The theory for calculating the absorption of laser radiation by hydrogen is outlined for the temperatures and pressures of common laboratory plasmas. Nonhydrogenic corrections for determining the absorption by helium are also included. The coefficients for the absorption of He-Ne laser radiation at the wavelengths of 0.633, 1.15, and 3.39 microns in a H plasma is presented for temperatures in the range from 10,000 to 40,000 K and electron number densities in the range from 10 to the 15th power to 10 to the 18th power per cu cm. The total absorption of a H-He plasma calculated from this theory is compared with the measured absorption. The theoretical composition of the H-He absorption is analyzed with respect to the significant absorption processes, inverse bremsstrahlung, photoionization, resonance excitation, and photodetachment.

Stallcop, J. R.↗
NASA NTRS1974

Inert gases in Sea of Fertility regolith

The content and isotopic composition were studied of inert gases -- He, Ne, Ar, Kr, and Xe -- in samples of lunar regolith returned by the Luna 16 automatic station. The samples were taken from depths of about 12 and 30 cm. The high concentrations of inert gases exceed by several orders their concentrations observed in ordinary stony meteorites. The gases in lunar regolith were a complex mixture of gases of different origins: Solar, cosmogenic, radiogenic, and so on. Solar wind gases predominated, distributed in the thin surficial layer of the regolith grains. The concentrations of these gases in the surficial layer is several cubic centimeters per gram. The isotopic composition of the inert gases of solar origin approaches their composition measured in gas-rich meteorites.

Vinogradov, A. P.↗
NASA NTRS1974

A facsimile system using room-temperature injection-laser scanning

This paper reports the first use of CW room-temperature injection lasers in a scanning facsimile system. The document reader can resolve about 2000 spots in each horizontal line of its raster scan, which is close to the performance attained using an He-Ne gas laser. The results obtained thus suggest that these small, efficient lasers can replace gas lasers in many applications.

Goedertier, P. V.↗
NASA NTRS1974

Composition of heavy cosmic rays from 25 to 180 MeV per atomic mass unit

Relative abundances of elements from neon through zinc in the energy range from 25 to 180 MeV per amu have been determined from particle tracks in polycarbonate detectors exposed on the Apollo 16 mission. The ratios of elemental abundances of Ne + Si and 17 less than Z less than 25 to Fe + Co + Ni are found to be 5.8 plus or minus 1.9 and 2.1 plus or minus 0.7, respectively, in agreement with the results from cellulose triacetate detectors by O'Sullivan et al. (1973). These results imply that the heavy particles observed are predominantly galactic in origin. The availability to investigators of unetched plastic detectors exposed to solar-flare particles on the Apollo 16 mission is noted.

Fleischer, R. L.↗
NASA NTRS1974

The fine structure of the solar atmosphere in the far ultraviolet

The paper describes qualitatively the spatial distribution of UV emission obtained from high resolution spectroheliograms in the UV emission lines He I, He II, O IV, O V, and Ne VII photographed during a sounding rocket flight. Broad band filtergrams of the far UV solar corona were also obtained. The results confirmed that spicules are the location of UV emission. Most of the UV emission in the temperature range from 100,000 to 200,000 K is concentrated in and around the spicules and this concentration decreases with increasing temperatures. Four different areas of UV emission are discussed. The He I and He II spectroheliogram observations showed He to be suppressed in the coronal holes, polar caps, and sunspots.

Brueckner, G. E.↗
NASA NTRS1974

Primordial noble gases in separated meteoritic minerals. II

A stepwise heating technique was used to analyze eight silicate samples from the Orgueil carbonaceous chondrite for He, Ne, Ar, and Xe. Six samples, of which two were etched with NaOH, were density fractions. The other two samples were grain-size fractions separated according to their ability to form a colloid at pH 11.5. Results showed the LiCl separation procedure to be gentler than the NaOH procedure. All fractions were found to be deficient in cosmogenic neon. Above 950 C the fractions gave low 20Ne/22Ne ratios particularly in the low-density and noncolloidal fraction. Compared to the other fractions the fraction from 2.35 to 2.45 g/cu cm contained less Xe and released it more rapidly at low temperatures.

Herzog, G. F.↗
NASA NTRS1975

Brillouin-scattering measurements of the acoustic absorption coefficient in liquid CS2

High-resolution Brillouin spectra were recorded for light scattered at small angles from liquid CS2. The use of a single-mode He-Ne laser, locked in frequency to a Fabry-Perot interferometer, permitted measurements of line widths of the order of 10 MHz for frequencies in the range 300-1000 MHz. These measurements extend previous Brillouin line-width measurements at higher frequencies into the region where relaxation effects are dominant and connect the optical measurements with lower-frequency acoustical data.

Coakley, R. W.↗
NASA NTRS1975

Oxygen-to-neon abundance ratio in the solar corona

The oxygen-to-neon abundance ratio in the solar corona is determined to be 4.7 + or - 1.5 on the basis of a relatively model-independent analysis utilizing 25 separate measurements of the O VIII to Ne IX resonance line ratio. The stated uncertainty includes random and possible systematic experimental error in the data but does not include possible error in the calculated flux ratios which have been fitted to the observations. This abundance ratio is smaller than most published results based upon EUV or X-ray observations but is in good agreement with direct measurements of flare cosmic rays.

Acton, L. W.↗
NASA NTRS1975

Infrared forbidden lines in H II regions and planetary nebulae

Emissivity coefficients are calculated as functions of electron density and temperature for the IR forbidden lines between 2 and 300 microns of the elements and ionization stages most abundant in H II regions and planetary nebulae. The effect of self-absorption is investigated, and a method is presented for estimating when self-absorption may be important. The IR line spectrum of the Orion Nebula is predicted using the emissivity coefficients, and ionic abundances are derived for the Ar III, S IV, and Ne II forbidden lines in a number of planetary nebulae. The sulfur abundance and sulfur/oxygen ratio are discussed for H II regions and planetary nebulae. The average sulfur/oxygen ratio is found to be about 0.05 for gaseous nebulae.

Simpson, J. P.↗
NASA NTRS1974

Inert gases in twelve particles and one 'dust' specimen from the Lunar-16 sample

Mass spectrography was used to measure inert gases in lunar breccia and basalt particles. The He-4/Ne-20 ratio (mean value of 49) in the breccia was systematically lower than in basalt (mean value of 78). Possibly, this may be due to fractionation of He and Ne during and after breccia formation. Pronounced differences observed in the He-4/Ne-3 ratio are attributed to the presence of variable quantities of cosmogenic He-3. This means that either the solar wind intensity varied in time, or that small-ratio particles were exposed to solar radiation rich in He-3 and/or H-3. The exposure ages of four particles are several hundred million years. The Ar-40/Ar-36 ratio is 0.65 for breccia and basalts.

Heymann, D.↗
NASA NTRS1975

Phenomenological treatments of cross-sections for proton and hydrogen impact below 1 keV on molecular nitrogen

An analytic independent-particle model is used to construct static potentials to describe the interaction of hydrogen-like ions with atoms and molecules. Parameters of the ion-atom potential are determined from ab initio total energy minimization procedure. The elastic scattering of He(+) from Ne and Ar is investigated as a test case and comparison is made with experiment. The model is then used in conjunction with low energy H(+)-N2 experimental data to construct differential and total cross-sections for the scattering of protons and hydrogen in the energy range of 10 eV to 1 keV from molecular nitrogen. Analytic forms are used to parametrize these cross-sections to facilitate their use in the calculation of energy deposition by protons and hydrogen atoms in atmospheric gases.

Porter, H. S.↗
NASA NTRS1975

Solar X-ray spectroscopy with spatial resolution

Preliminary results from a solar X-ray spectroscopic experiment are presented. The data emphasize the nonhomogeneous and multithermal nature of the corona. The oxygen-to-neon abundance ratio in the corona is found to be about 4.7, as derived from the O VIII-to-Ne IX resonance-line photon flux ratio.

Acton, L. W.↗
NASA NTRS1975

The nebulosity around 3C 48

Results are reported for spectrophotometric measurements of the nebulosity around the quasar 3C 48 which were made with an image-tube scanner on a 3-m telescope. The forbidden emission lines of O III (5007 and 4959 A), Ne III (3869 A), and O II (3727 A) are detected in the nebulosity north of the quasar nucleus and are found to be narrower than those present in the nucleus, but with larger equivalent widths and a slightly larger redshift. No emission lines are detected south of the nucleus, and the continuum on the north is shown to be dominated by scattered continuum radiation from the central quasar. It is suggested that the hot gas responsible for the emission lines may be either part of a shell or disk rotating about the quasar or gas ejected from it.

Wampler, E. J.↗
NASA NTRS1977

Second-generation PMR polyimides

Continuing research has resulted in development of polyimides with improved thermo-oxidative stability at 589 K. Polyimides are based on dimethyl ester of 4,4'-(hexafluoro-isopropylidene)-bis(phthalic acid) (HFDE) and p-phenylenediamine (PPDA) and NE.

Serafini, T. T.↗
NASA NTRS1977

Servo corrects interferometer-mirror tilt

Three detectors sense He-Ne laser beam; one senses reference phase while others, at right angles to first, sense phase offset for each axis. Analog output of axis detectors is multiplied separately by reference output to give X and Y error signals that are then fed to respective X and Y actuators.

Schindler, R. A.↗
NASA NTRS1975

Tectonic Structure of Alaska as Evidenced by ERTS Imagery and Ongoing Seismicity

The author has identified the following significant results. A mosaic was constructed from selected portions of eleven LANDSAT images at a scale of 1:1,000,000. Band 7 images were utilized because of their superior haze-cutting characteristics. The area is clearly dominated by two principal features; these are the Denali and Castle Mountain-Fairweather fault systems which traverse the mosaic from east to west near the northern and southern margins. An interesting feature is the apparent graben formed by the western flanks of the Talkeetna and Chugach Ranges, and the eastern flank of the Alaska Range. The most significant aspect to the mosaic is a dominant NE-SW striking structural grain of the Talkeetna Mountains-Alaska Range complex.

Gedney, L. D.↗