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At least 325 records · Page 18
All sourcesNASA NTRSDOE OSTI
NASA NTRS1972

Preliminary examination of lunar samples

The morphology, mineralogy, petrology, and chemistry of the samples returned from the Apollo 15 landing site are discussed. A selenological description of the area from which the samples were taken is given. The diversity of the samples and the variety of sample environments found at the Apollo 15 site have resulted in several hypotheses that relate individual samples to local situations after even a preliminary examination of the samples. Several somewhat speculative hypotheses that relate individual samples to a geological framework are discussed in the hope that the hypotheses will provide guidelines for more detailed studies of the samples to arrive at an integrated understanding of the selenology of the Apollo 15 site.

Source record↗
NASA NTRS1972

Preliminary examination of Surveyor 3 components for impact phenomena

Two pieces of the Surveyor 3 spacecraft recovered during the Apollo 12 mission were examined for secondary lunar ejecta and micrometeorite impacts. One piece was section E of the aluminum strut; the other was the nickel-coated beryllium television camera mirror.

Hallgren, D. S.↗
NASA NTRS1972

Results of examination of the returned Surveyor 3 samples for particulate impacts

The television housing and a section of the strut of the radar altimeter and Doppler velocity sensor were examined optically and with a scanning electron microscope for particulate impacts. The white surface of the camera was discolored during the months the Surveyor 3 was on the moon; however, most of the craters must have occurred as a result of lunar dust sandblasted by the LM exhaust. The polished section of the strut exhibits contamination which appears brown and seems to be partially composed of crystals. Electron microscopic analysis of the strut section indicated no craters of hypervelocity impact origin, confirmed pitting density results of the optical scans, and indicated that material in the craters is of lunar origin. No meteorite impacts larger than 25 microns were detected on the tubing section.

Cour-Palais, B. G.↗
NASA NTRS1972

Examination of returned Surveyor 3 camera visor for alpha radioactivity

The TV camera visor was placed in a vacuum chamber and examined for alpha radioactivity using an alpha-scattering instrument, and plates covered with the same paint and made at the same time as the visor were used as a control. The spectra of visor and plates are very similar, and it is concluded that the gross activity on the visor is due entirely to the activity of the paint. The data were used to obtain the amount of Po-210 activity on the lunar surface. It is felt that the lack of detected alpha radioactivity does not indicate a lack of activity on the moon, since dust layers were knocked off the visor.

Economou, T. E.↗
NASA NTRS1972

An electron microscopy examination of primary recrystallization in TD-nickel.

Primary recrystallization in TD-nickel 1 in. bar has previously been regarded as the process by which the initial fine grain structure is converted to a coarse grain size (increases in grain size by 500 times) under suitable deformation and annealing conditions. This process is dependent on deformation mode. While it occurs readily after rolling transverse to the bar axis and annealing (800 C), it is completely inhibited by longitudinal rolling and swaging deformations, even for very high (1320 C) annealing temperatures. A transmission electron microscopy examination of deformation and annealing substructures indicates that primary recrystallization in TD-nickel 1 in. bar actually occurs on the sub-light optical level, to produce a grain structure similar in size to the initial fine grained state.

Petrovic, J. J.↗
NASA NTRS1972

A critical examination of the validity of simplified models for radiant heat transfer analysis.

Examination of the directional effects of the simplified models by comparing the experimental data with the predictions based on simple and more detailed models for the radiation characteristics of surfaces. Analytical results indicate that the constant property diffuse and specular models do not yield the upper and lower bounds on local radiant heat flux. In general, the constant property specular analysis yields higher values of irradiation than the constant property diffuse analysis. A diffuse surface in the enclosure appears to destroy the effect of specularity of the other surfaces. Semigray and gray analyses predict the irradiation reasonably well provided that the directional properties and the specularity of the surfaces are taken into account. The uniform and nonuniform radiosity diffuse models are in satisfactory agreement with each other.

Toor, J. S.↗
NASA NTRS1972

Examination of UC-ZrC after long term irradiation at thermionic temperature

Two fluoride tungsten clad UC-ZrC fueled capsules, designated as V-2C and V-2D, were examined a hot cell after irradiation in NASA Plum Brook Reactor at a maximum cladding temperature of 1930 K for 11,089 and 12,031 hours to burnups of 3.0 x 10 to the 20th power and 2.1 x 10 to the 20th power fission/c.c. respectively. Percentage of fission gas release from the fuel material was measured by radiochemical means. Cladding deformation, fuel-cladding interaction and microstructures of fuel, cladding, and fuel-cladding interface were studied metallographically. Compositions of dispersions in fuel, fuel matrix and fuel-cladding interaction layer were analyzed by electron microprobe techniques. Axial and radial distributions of burnup were determined by gamma-scan, autoradiography and isotopic burnup analysis. The results are presented and discussed in conjunction with the requirements of thermionic fuel elements for space power application.

Yang, L.↗
NASA NTRS1973

The examination of urine samples for pathogenic microbes by the luciferase assay for ATP. 1: The effect of the presence of fungi, fungal like bacteria and kidney cells in urine samples

A method for accurately determining urinary tract infections in man is introduced. The method is based on adenosine triphosphate (ATP) concentration in urine samples after removing nonbacterial ATP. Adenosine triphosphate concentration is measured from the bioluminescent reaction of luciferase when mixed with ATP. An examination was also made of the effectiveness of rupturing agents on monkey kidney cells Candia albicans, a Rhodotorula species, and a Streptomyces species in determining whether these cells could contribute ATP to the bacterial ATP value of a urine sample.

Bush, V. N.↗
NASA NTRS1973

Results of Uranium Dioxide-Tungsten Irradiation Test and Post-Test Examination

A uranium dioxide (UO2) fueled capsule was fabricated and irradiated in the NASA Plum Brook Reactor Facility. The capsule consisted of two bulk UO2 specimens clad with chemically vapor deposited tungsten (CVD W) 0.762 and 0.1016 cm (0.030-and 0.040-in.) thick, respectively. The second specimen with 0.1016-cm (0.040-in.) thick cladding was irradiated at temperature for 2607 hours, corresponding to an average burnup of 1.516 x 10 to the 20th power fissions/cu cm. Postirradiation examination showed distortion in the bottom end cap, failure of the weld joint, and fracture of the central vent tube. Diametral growth was 1.3 percent. No evidence of gross interaction between CVD tungsten or arc-cast tungsten cladding and the UO2 fuel was observed. Some of the fission gases passed from the fuel cavity to the gas surrounding the fuel specimen via the vent tube and possibly the end-cap weld failure. Whether the UO2 loss rates through the vent tube were within acceptable limits could not be determined in view of the end-cap weld failure.

Collins, J. F.↗
NASA NTRS1973

Postoperational examination of an externally configured thermionic converter

An externally configured thermionic converter was operated for 200 h. The converter was disassembled and examined to determine internal changes as a result of operation. The metal/ceramic seals and all joints were unaffected by operation. Converter output voltage and operational time were sufficient to produce electrolysis of stabilized zirconia spacers used in the converter. Surface analysis of the electrode surfaces indicated the presence on the tungsten emitter of only oxygen, carbon, and silicon. The niobium collector was, however, 25 to 40% covered with other elements. This coverage represented all elements present within the converter as construction materials other than silicon and tungsten, which were not detected on the collector, and carbon, which was detected only in small amounts.

Phillips, W. M.↗
NASA NTRS1973

Visual examination apparatus

An automated visual examination apparatus for measuring visual sensitivity and mapping blind spot location is described. The apparatus includes a projection system for displaying to a patient a series of visual stimuli, a response switch enabling him to indicate his reaction to the stimuli, and a recording system responsive to both the visual stimuli per se and the patient's response. The recording system provides a correlated permanent record of both stimuli and response from which a substantive and readily apparent visual evaluation can be made.

Haines, R. F.↗
NASA NTRS1972

Meteoroid activity on the lunar surface from the Surveyor 3 sample examination.

The Surveyor 3 television camera shroud and polished aluminum tube, retrieved as a result of the Apollo 12 mission after 2.5 years on the lunar surface, were examined for evidence of meteoroid impact. Resulting estimates of the meteoroid flux in the lunar vicinity are shown to be in good agreement with the Lunar Orbiter penetration rates. In addition, the relationship between a derived lunar-surface meteoroid cumulative-flux model and the comparable near-earth model is discussed in the light of theoretical predictions. It is shown that the effect of the gravitational field of the earth on the near-earth environment was greater than previously predicted.

Cour-Palais, B. G.↗
NASA NTRS1972

Study of excess Fe metal in the lunar fines by magnetic separation, Moessbauer spectroscopy, and microscopic examination.

A simple and convenient method of making quantitative magnetic separations has been applied to the lunar fines. The fractions obtained form groups containing distinctively different particle types; thus, it appears that magnetic separation in itself many be a useful way of characterizing lunar fines. Moessbauer studies of fines 10084 show that the metal cannot contain more than about 1.5% Ni, implying that by far the bulk of the metal results from reduction rather than from direct meteoritic addition. Microscopic examination of magnetic separates from 15101 fines suggests that reduction of Fe accompanies every major impact event on the moon.

Housley, R. M.↗
NASA NTRS1973

Examination of T-111 clad uranium nitride fuel pins irradiated up to 13,000 hours at a clad temperature of 990 C

The examination of 27 fuel pins irradiated for up to 13,000 hours at 990 C is described. The fuel pin clad was a tantalum alloy with uranium nitride as the nuclear fuel. Two nominal fuel pin diameters were tested with a maximum burnup of 2.34 atom percent. Twenty-two fuel pins were tested for fission gas leaks; thirteen pins leaked. Clad ductility tests indicated clad embrittlement. The embrittlement is attributed to hydrogen from an n,p reaction in the fuel. Fuel swelling was burnup dependent, and the amount of fission gas release was low, generally less than 0.5 percent. No incompatibilities between fuel, liner, and clad were in evidence.

Slaby, J. G.↗
NASA NTRS1973

Further examination of pilot instrument scanning data and development of a new link value estimator

Pilot instrument scanning data collected during simulated transport instrument landing approaches is examined. Deterministic features of random pilot instrument scanning behavior are confirmed to be: transitions in point of eye fixation which originate and terminate on the same instrument are rare; and transitions in point of eye fixation which originate on one secondary instrument and terminate on another secondary instrument are rare. Link value estimators are developed using statistics and these experimental facts. The result has a special significance when there is but a single primary instrument, a flight director. The result is used to simplify the iterative computational procedure of STI's display theory to a non-iterative procedure for the flight director case.

Hofmann, L. G.↗
NASA NTRS1974

Examination of the influence of coatings on thin superalloy sections. Volume 1: Description and analysis

The effects of an aluminide coating and of section thickness were investigated on two cast nickel-base superalloys. Cast section thickness ranged from 0.038 cm to 0.15 cm. Simulated engine exposures in a jet fuel burner rig with cyclic air cooling were studied. The effects of surface machining before coating and re-machining and re-coating after exposures were examined. The properties evaluated included tensile strength, stress rupture, high-cycle mechanical fatigue, and thermal fatigue. A metallurgical analysis was made of the microstructures of the coated and uncoated alloy.

Kaufman, M.↗
NASA NTRS1975

Results of eye examination

Five pocket mice (Perognathus longimembris) were flown on Apollo XVII, and four survived. All the eyes, except one eye from the dead flight mouse, were examined histologically. In the four surviving mice, a total of five cosmic-ray particles which had registered in the subscalp particle detectors had trajectories that intersected the eyes. Four of them (Z = 6.9 for three of the particles and Z greater than or equal to 10 for the fourth) most likely went through the head before reaching the particle detector, while the thindown direction of the fifth (Z greater than or equal to 10) was not determinable. The retinas of the flight animals were found free from histological alterations such as might have been expected from encounters with cosmic-ray particles.

Philpott, D. E.↗