SEARCH · Search NASA
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.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Optically-clear shatter-resistant safety shield protects workers from implosion and explosion of vacuum and pressure windows. Plastic shield is inexpensive and may be added to vacuum chambers, pressure chambers, and gas-filling systems.
The use of time and motion study methods to evaluate force feedback in remote manipulation tasks are described. Several systems of time measurement derived for industrial workers were studied and adapted for manipulator use. A task board incorporating a set of basic motions was designed and built. Results obtained from two subjects in three manipulation situations for each are reported: a force-reflective manipulator, a unilateral manipulator, and the unaided human hand. The results indicate that: (1) a time-and-motion study techniques are applicable to manipulation; and that (2) force feedback facilitates some motions (notably fitting), but not others (such as positioning).
This publication contains the technical papers from the five task groups that took part in the 1977 Ames Summer Study on Space Settlements and Industrialization Using Nonterrestrial Materials. The study was sponsored by the following NASA Headquarters organizations: Office of Space Science, Office of Aeronautics and Space Technology, and Office of Space Transportation Systems. The NASA Ames Research Center hosted the study and provided administrative support through its Life Sciences Directorate. Expert assistance in the many aspects of the study came from NASA Headquarters, NASA centers, universities, industry, and from individual consultants. This summer study was the largest and most comprehensive investigation of space manufacturing and habitation to date; forty senior research workers and ten students participated. The six-week study was preceded by several months of planning and preparation, and was followed by extensive work on manuscript checking, review, and assembly. The study topics reflected the research areas requiring the most intensive attention as ofrnid-1977; they were: Group I: Regenerative life-support systems and controlled environment agriculture. Group II: Parametric studies of efficient habitats in space. Time and cost analysis of a space manufacturing program plan. Group III: Detection and analysis of special classes of asteroids suitable as material resources for space manufacturing; studies of retrieval missions. Group IV: Electromagnetic mass drivers for use as interorbital engines, as devices to launch lunar material into space, and as tugs for the retrieval of asteroidal material. Group V: Chemical processing of non terrestrial material in space; manufacture of metals and glass fibers, beneficiation, and design of processing plants. These five task groups each produced two or more technical papers, signed by the contributing members. The papers were subjected to independent peer review by scientists not connected with the study. During the course of the study, frequent formal and informal exchanges of information occurred between task groups, so that the entire effort evolved in a coherent fashion and was directed toward common goals. However, each group remained responsible for the choice of its topics and for its conclusions. A listing of all the participants is given on pages vii-x. It would be inappropriate for me to single out particular people or groups for special mention, since all involved applied their skills with dedication and enthusiasm. Instead, I thank everyone for their contributions to the success of the study, and also for making it a united and warmly cooperative personal experience.
Robotic vision, involving the use of a vision system to control a process, is discussed. Design and selection of active sensors employing radiation of radio waves, sound waves, and laser light, respectively, to light up unobservable features in the scene are considered, as are design and selection of passive sensors, which rely on external sources of illumination. The segmentation technique by which an image is separated into different collections of contiguous picture elements having such common characteristics as color, brightness, or texture is examined, with emphasis on the edge detection technique. The IMFEX (image feature extractor) system performing edge detection and thresholding at 30 frames/sec television frame rates is described. The template matching and discrimination approach to recognize objects are noted. Applications of robotic vision in industry for tasks too monotonous or too dangerous for the workers are mentioned.
IRIS, a telescope consisting of a large-area precision Cerenkov detector, scintillators, spark chambers, and a passive stack of Lexan polycarbonate track detectors, was exposed to the primary cosmic radiation for 6.6 sq m sr hr in a balloon flight in 1976. This measurement has yielded the isotopic composition of the iron-group elements Cr, Mn, Fe, and Ni with an average mass resolution of 0.65 amu for the energies 320-500 MeV per amu at the detector. This experiment places the most severe constraints to date on deviation from solar-system composition of the source of the cosmic radiation. Upper limits of 10 percent are placed on the ratios Fe-54/Fe-56 and Fe-58/Fe-56, which are inconsistent with large departures from solar system source composition reported by other workers. The isotopic measurements of Fe and Ni preclude the possibility that these cosmic rays were produced in a single e-process zone. The mean mass of Mn is less than 55, indicating the presence of electron-capture species produced by spallation.
Detailed petrographic examination of 22 thin sections from the impregnated portion of the Apollo 16 double drive tube supports the findings of previous workers. A well-gardened unit exists at the top of 60010, indicated petrographically by an increase in agglutinates near the lunar surface. There is a coarse-grained anorthositic layer near the bottom of 60009. Few, if any, of the modal variations are stratigraphically correlatable with the deep drill core 60002-7, which was recovered 50 m southwest of drive tube 60009/60010.
An electron microprobe study was conducted on glass fragments taken from the fusion crust and an internal glass-lined vein in the H-5 chondrite Collescipoli. Microprobe analyses of the glasses revealed an unusual fusion crust composition, and analyses of glass from inside the meteorite showed compositions expected for a melt of an H-group chondrite. Studies of fusion crusts by previous workers, e.g., Krinov and Ramdohr, showed that fusion crusts contain large amounts of magnetite and other oxidized minerals. The Collescipoli fusion crusts do contain these minerals, but they also contain relatively large amounts of reduced metal, sulphide, and a sodium-rich glass. This study seems to indicate that Collescipoli preserved an early type of fusion crust. Oxidation was incomplete in the fusion crust melt that drained into a crack. From this study it is concluded that fusion crust formation does not invariably result in complete oxidation of metal and sulphide phases.
Inexpensive, readily assembled pointer aims X-ray machine for welded assembly radiographs. Plumb bob used for vertical alinement and yardstick used to visualize X-ray paths were inconvenient and inaccurate. Pointer cuts alinement time by one-half and eliminates necessity of retakes. For 3,000 weld radiographs, pointer will save 300 worker-hours and significant materials costs.
Device for measuring depth or thickness reads distance of penetration by small-diameter probe. It was developed specifically to measure thickness of wet (uncured) insulation applied to Space Shuttle structures; thin probes penetrate wet insulation to substrate, and reference surface on gage is then positioned against outer surface of insulation to measure its thickness. Gage is easy to use, even by workers wearing gloves or other protective clothing, and allows remote reading and recording of production data.
Wedge joint links structural members in manual, remote, or automated assemblies. Joint is simple enough to be assembled by undersea divers, workers in nuclear reactors, and other wearing gloves or bulky clothing. Combination of wedging angles on parts overcomes structural misalinements and forces assembly into true position as locking sleeve moves into place. Joint transmits tension, compression, bending moments and torsion and is inherently insensitive to thermal excursions, vibration, and machining tolerance buildup.
An introduction to the theory of corona discharge and electrostatic phenomena is presented. The theory is mainly qualitative so that workers in the field should not have to go outside this manual for an understanding of the relevant phenomena. Some of the problems that may occur with the space shuttle in regard to electrical discharge are discussed.
The U-238/U-235 ratios for nine bulk chondritic meteorites and a terrestrial basalt were measured. The total range in U-238/U-235 determined for both total meteorites and for acid leaches was from 137.2 terrestrial U. The typical errors in a single determination are plus or minus 6 per thousand (2 sigma m) for a 2 ng U sample from a chondrite. Taking the extreme values of delta U-235 for each measurement the maximum amount of excess U-235 that can be allowed to be present ranges from 200 million to 2 billion atoms per gram of bulk meteorite. These results do not support the claims of variations in U-238/U-235 at the percentage levels or number of excess U-235 atoms in some of the same meteorites as reported by several other previous workers.
The galaxy density, spiral content, and richness of the 23 poor clusters of galaxies cataloged by Morgan and co-workers are determined and compared with those of Abell clusters. It is found that Morgan's clusters generally represent a smooth continuation of the galaxy clustering spectrum from the rich Abell clusters. This continuity in optical properties implies a corresponding continuity in X-ray properties. The extended X-ray emission recently detected from several of Morgan's clusters is consistent with the amount of thermal bremsstrahlung emission expected on the basis of the present optical observations and previous correlations of X-ray-optical cluster properties. The fraction of cluster galaxies that are spirals is a sensitive function of the galaxy surface density, N(-)0.
Energy spectra of cosmic-ray nuclei boron to iron have been measured from 2 GeV per nucleon to beyond 100 GeV per nucleon. The data were obtained using an ionization calorimeter flown on a balloon from Palestine, Texas. The 3450 kg payload floated at 7 g/sq cm for almost 24 hours. The results are in excellent agreement with those of other workers where overlaps exist. The spectra are not consistent with single power laws, and demonstrate the power of using a single technique sensitive over a large dynamic range. The data are consistent with the leaky box model of cosmic-ray propagation. The boron data indicate that the cosmic-ray escape length decreases with increasing energy as E to the -(0.4 + or - 0.1) up to 100 GeV per nucleon. Secondary nuclei from iron are also consistent with this dependence. Predicted changes in the energy dependence of the ratios of primary nuclei O/C and (Fe + Ni)/(C + O) are also observed.
Damaged butyl rubber products are renewed by spray technique originally developed for protective suits worn by NASA workers. A commercial two-part adhesive is mixed with Freon-113 (or equivalent) trichlorotrifluoroethane to obtain optimum viscosity for spraying. Mix is applied with an external-air-mix spray gun.
The individual exposure integral noise load on workers before the beginning of hearing impairment was determined for a group of 20 male miners who had worked with drilling equipment and harvesters for 8 to 20 years before the onset of the disability. Results show that the total exposure energy load of about 4 kw x h sq m, obtained by miners in the examined group, resulted in occupational injury to the auditory organ (cochlear neuritis) in 75% of the cases. The equivalent energy level of noise computed according to the date of total energy load is roughly 99 db A, which significantly exceeds the permissible amount of 85 db A. There is a correlation (r = 0.77) between the integral exposure energy noise on the aural analyzer in the degree of increase in the total threshold for the mean speech range.
Livability aboard the space shuttle orbiter makes it possible for men and women scientists and technicians in reasonably good health to join superbly healthy astronauts as space travelers and workers. Features of the flight deck, the mid-deck living quarters, and the subfloor life support and house-keeping equipment are illustrated as well as the provisions for food preparation, eating, sleeping, exercising, and medical care. Operation of the personal hygiene equipment and of the air revitalization system for maintaining sea level atmosphere in space is described. Capabilities of Spacelab, the purpose and use of the remote manipulator arm, and the design of a permanent space operations center assembled on-orbit by shuttle personnel are also depicted.
A number of techniques can be used to reduce noise in poultry processing plants. In general, covering the ceiling with a noise-absorbing medium is a practical first step. Once the reflected noise levels are abated, treatment of specific identifiable noise courses can take place. The development, flammability, and mechanical properties of acoustic panels to be vertically suspended from the ceiling are discussed as well as the covers need to comply with USDA cleanability requirements. The isolation of drive motors and pumps from large expansive areas, the muffling of pneumatic devices, and the insulation of ice chutes are methods of source quieting. Proper maintenance of machinery and vibration monitoring are also needed to reduce hearing damage risk and to improve worker productivity and employee/supervisor relations.