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Results for “Non-programmatic”

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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27 records · Page 2

Asteroidal water within fluid inclusion-bearing halite in an H5 chondrite, Monahans (1998)

Crystals of halite and sylvite within the Monahans (1998) H5 chondrite contain aqueous fluid inclusions. The fluids are dominantly sodium chloride-potassium chloride brines, but they also contain divalent cations such as iron, magnesium, or calcium. Two possible origins for the brines are indigenous fluids flowing within the asteroid and exogenous fluids delivered into the asteroid surface from a salt-containing icy object.

Non-programmatic↗

The role of biomineralization in microbiologically influenced corrosion

Synthetic iron oxides (goethite, alpha-FeO.OH; hematite, Fe2O3; and ferrihydrite, Fe(OH)3) were used as model compounds to simulate the mineralogy of surface films on carbon steel. Dissolution of these oxides exposed to pure cultures of the metal-reducing bacterium, Shewanella putrefaciens, was followed by direct atomic absorption spectroscopy measurement of ferrous iron coupled with microscopic analyses using confocal laser scanning and environmental scanning electron microscopies. During an 8-day exposure the organism colonized mineral surfaces and reduced solid ferric oxides to soluble ferrous ions. Elemental composition, as monitored by energy dispersive x-ray spectroscopy, indicated mineral replacement reactions with both ferrihydrite and goethite as iron reduction occurred. When carbon steel electrodes were exposed to S. putrefaciens, microbiologically influenced corrosion was demonstrated electrochemically and microscopically.

Non-programmatic↗

Cardiovascular effects of microgravity: evolution of understanding

The understanding of cardiovascular effects of spaceflight has evolved throughout the course of the American manned spaceflight program. Originally descriptive in nature, the present understanding is based on empiric measurements of vascular volume, cardiac output, vascular reflexes, and peripheral and central autonomic control. More detailed understanding of cardiovascular effects has allowed us to separate those symptoms from symptoms caused by musculoskeletal or neurovestibular abnormalities.

Non-programmatic↗

Detection of abundant ethane and methane, along with carbon monoxide and water, in comet C/1996 B2 Hyakutake: evidence for interstellar origin

The saturated hydrocarbons ethane (C2H6) and methane (CH4) along with carbon monoxide (CO) and water (H2O) were detected in comet C/1996 B2 Hyakutake with the use of high-resolution infrared spectroscopy at the NASA Infrared Telescope Facility on Mauna Kea, Hawaii. The inferred production rates of molecular gases from the icy, cometary nucleus (in molecules per second) are 6.4 X 10(26) for C2H6, 1.2 X 10(27) for CH4, 9.8 X 10(27) for CO, and 1.7 X 10(29) for H2O. An abundance of C2H6 comparable to that of CH4 implies that ices in C/1996 B2 Hyakutake did not originate in a thermochemically equilibrated region of the solar nebula. The abundances are consistent with a kinetically controlled production process, but production of C2H6 by gas-phase ion molecule reactions in the natal cloud core is energetically forbidden. The high C2H6/CH4 ratio is consistent with production of C2H6 in icy grain mantles in the natal cloud, either by photolysis of CH4-rich ice or by hydrogen-addition reactions to acetylene condensed from the gas phase.

Non-programmatic↗

Managing fatigue in operational settings 2: An integrated approach

The six domains that must be addressed in managing fatigue in operational settings are identified, and examples of how the aviation industry is dealing with the problems in each domain are given. Challenges facing healthcare providers in managing fatigue are also discussed.

Non-programmatic↗

Managing fatigue in operational settings. 1: Physiological considerations and countermeasures

The authors consider three aspects of managing fatigue in the workplace. They provide a brief overview of important scientific findings related to sleep and circadian physiology that establish the psychobiological foundation of fatigue. Their major focus is on the relevance of these findings to operational settings. In addition, they provide examples to describe practical fatigue countermeasures that can be used in operational settings.

Review, Tutorial↗

Extravehicular mobility unit training and astronaut injuries

BACKGROUND: Astronaut spacewalk training can result in a variety of symptom complaints and possible injuries. This study quantified and characterized signs, symptoms, and injuries resulting from extravehicular activity spacesuit training at NASA's Neutral Buoyancy Laboratory, Johnson Space Center, Houston, TX, immersion facility. METHODS: We identified the frequency and incidence of symptoms by location, mechanisms of injury, and effective countermeasures. Recommendations were made to improve injury prevention, astronaut training, test preparation, and training hardware. At the end of each test, a questionnaire was completed documenting signs and symptoms, mechanisms of injury, and countermeasures. RESULTS: Of the 770 tests, there were 190 in which suit symptoms were reported (24.6%). There were a total of 352 reported suit symptom comments. Of those symptoms, 166 were in the hands (47.16%), 73 were in the shoulders (20.7%), and 40 were in the feet (11.4%). Others ranged from 6.0% to 0.28%, respectively, from the legs, arms, neck, trunk, groin, and head. Causal mechanisms for the hands included moisture and hard glove contacts resulting in fingernail injuries; in the shoulders, hard contact with suit components and strain mechanisms; and in the feet, hard boot contact. The severity of symptoms was highest in the shoulders, hands, and feet. CONCLUSIONS: Most signs and symptoms were mild, self-limited, of brief duration, and were well controlled by available countermeasures. Some represented the potential for significant injury with consequences affecting astronaut health and performance. Correction of extravehicular activity training-related injuries requires a multidisciplinary approach to improve prevention, medical intervention, astronaut training, test planning, and suit engineering.

Non-programmatic↗

Real-time visualization of cross-sectional data in three dimensions

This paper describes a technique for viewing and interacting with 2-D medical data in three dimensions. The approach requires little pre-processing, runs on personal computers, and has a wide range of application. Implementation details are discussed, examples are presented, and results are summarized.

Non-programmatic↗