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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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At least 109 records · Page 6
All sourcesNASA NTRSDOE OSTI
NASA NTRS1977

Evaluation of performance impairment by spacecraft contaminants

The environmental contaminants (isolated as off-gases in Skylab and Apollo missions) were evaluated. Specifically, six contaminants were evaluated for their effects on the behavior of juvenile baboons. The concentrations of contaminants were determined through preliminary range-finding studies with laboratory rats. The contaminants evaluated were acetone, methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK), trichloroethylene (TCE), heptane and Freon 21. When the studies of the individual gases were completed, the baboons were also exposed to a mixture of MEK and TCE. The data obtained revealed alterations in the behavior of baboons exposed to relatively low levels of the contaminants. These findings were presented at the First International Symposium on Voluntary Inhalation of Industrial Solvents in Mexico City, June 21-24, 1976. A preprint of the proceedings is included.

Geller, I.↗
NASA NTRS1977

Toxicological aspects of the Skylab program

A current state-of-the-art trace gas removal technology is demonstrated that provides for carbon monoxide removal through an outgassing screening program for nonmetallic materials of the Skylab cabin interior. Material selection included both outgassing data and LD sub 50 information, as well as chemical analyses on pyrolysis products to prevent toxic inhalation exposures of spacecrews.

Rippstein, W. J., Jr.↗
NASA NTRS1977

A review of available LC/50/ data

Several gaseous products of pyrolysis and combustion have been evaluated for LC/50/, defined as the concentration of toxic gas in the atmosphere being inhaled by test animals that will produce death in 50% of the animals within a given time period. The products tested included CO, HCl, HF, HCN, NO2, and SO2. It was found that HCN and NO2 were consistently the most toxic of the gases reviewed, and that mice were more susceptible than rats to HCl and HF, although less susceptible than rats to NO2. Extrapolation of LC/50/ data to humans indicates that metabolic rate may be a valid basis for extrapolation when the toxicity mechanism is interference with oxygen transport and utilization, or pulmonary edema, but not when it is irritation and damage to the upper respiratory tract.

Hilado, C. J.↗
NASA NTRS1974

Design specification for the whole-body algorithm

The necessary requirements and guidelines for the construction of a computer program of the whole-body algorithm are presented. The minimum subsystem models required to effectively simulate the total body response to stresses of interest are (1) cardiovascular (exercise/LBNP/tilt); (2) respiratory (Grodin's model); (3) thermoregulatory (Stolwijk's model); and (4) long-term circulatory fluid and electrolyte (Guyton's model). The whole-body algorithm must be capable of simulating response to stresses from CO2 inhalation, hypoxia, thermal environmental exercise (sitting and supine), LBNP, and tilt (changing body angles in gravity).

Fitzjerrell, D. G.↗
NASA NTRS1980

Relative toxicity testing of spacecraft materials. 2: Aircraft materials

The relative toxicity of thermodegradation (pyrolysis/combustion) products of aircraft materials was studied. Two approaches were taken to assess the biological activity of the pyrolysis/combustion products of these materials: (1) determine the acute lethality to rats from inhalation of these pyrolysates and (2) examine the tendency for sublethal exposure to the pyrolysates to disrupt behavioral (shock avoidance) performance of exposed rats. The ralative importance of lethality vs. behavioral effects in selection of a material may be dictated by whether or not individuals potentially exposed to such products, would have an opportunity to escape if they were behaviorally capable of doing so. If so, the second parameter would assume greater importance, but if not the first parameter may be of much greater importance in selecting materials.

Lawrence, W. H.↗
NASA NTRS1982

Toxicity of thermal degradation products of spacecraft materials

Three polymeric materials were evaluated for relative toxicity of their pyrolysis products to rats by inhalation: Y-7683 (LS 200), Y-7684 (Vonar 3 on Fiberglass), and Y-7685 (Vonar 3 on N W Polyester). Criteria employed for assessing relative toxicity were (1) lethality from in-chamber pyrolysis, (2) lethality from an outside-of-chamber pyrolysis MSTL Procedure, and (3) disruption of trained rats' shock-avoidance performance during sub-lethal exposures to in-chamber pyrolysis of the materials.

Lawrence, W. H.↗
NASA NTRS1991

Evaluation of aerosolized medications during parabolic flight maneuvers

The goal was to visually evaluate the effect gravity has on delivery of medications by the use of various aerosol devices. During parabolic flight the same four aerosols were retested as performed in studio ground tests. It appears that the Cetacaine spray and the Ventolin inhaler function without failure during all test. The pump spray (Nostril) appeared to function normally when the container was full, however it appeared to begin to fail to deliver a full mist with larger droplet size when the container was nearly empty. The simple hand spray bottle appeared to work when the container was full and performed progressively worse as the container was emptied. During Apollo flights, it was reported that standard spray bottles did not work well, however, they did not indicate why. It appears that we would also conclude that standard spray bottles do not function as well in zero gravity by failing to produce a normal mist spray. The standard spray bottle allowed the fluid to come out in a narrow fluid stream when held with the nozzle either level or slightly tilted upward.

Lloyd, Charles W.↗
NASA NTRS1992

Human exposure limits to hypergolic fuels

Over the past four decades, many studies have been conducted on the toxicities of the rocket propellants hydrazine (HZ) and monomethylhydrazine (MH). Numerous technical challenges have made it difficult to unambiguously interpret the results of these studies, and there is considerable divergence between results obtained by different investigators on the inhalation concentrations (MAC's) for each toxic effect inducible by exposure to hypergolic fuels in spacecraft atmospheres, NASA undertook a critical review of published and unpublished investigations on the toxicities of these compounds. The current state of the art practices for similar studies. While many questions remain unanswered, MAC's were determined using the best available data for a variety of toxic endpoints for potential continuous exposure durations ranging from 1 hour to 180 days. Spacecraft MAC's (SMAC's) were set for each compound based on the most sensitive toxic endpoint at each exposure duration.

Garcia, H. D.↗
NASA NTRS1991

Development of lower body negative pressure as a countermeasure for orthostatic intolerance

Exposure to prolonged (1-4 hr) lower body negative pressure (LBNP) is a countermeasure against postflight orthostatic intolerance which is used in the Soviet space program and planned for use in the American space program. LBNP in combination with fluid-loading is believed to act by promoting a transient positive fluid balance resulting in an increase in vascular, as well as extravascular fluid. Inflight LBNP also may provide beneficial orthostatic effects by restoring baroreceptor reflex functions and/or lower body venous compliance. Current research efforts at the Johnson Space Center are directed toward increasing the effectiveness and efficiency of the LBNP and saline countermeasure. A promising avenue may involve combining pharmacologic agents, such as inhaled anti-diuretic hormone, or mineralocorticoids, with mechanical stimuli such as LBNP.

Fortney, Suzanne M.↗
NASA NTRS1992

Rett syndrome - Stimulation of endogenous biogenic amines

Transient hypercapnic hyperoxemia was induced in two Rett syndrome children by the administration of a gaseous mixture of 80 percent O2 and 20 percent CO2. Time course studies of neurotransmitters and their metabolites showed an immediate and marked increase in central biogenic amine turnover following inhalation of the gas mixture. The increased turnover of biogenic amines was associated with improved clinical changes. This suggests a coupled relationship and provides further support for an etiological role of neurotransmitter dysfunction in Rett syndrome. In a complementary study, elevation of pulmonary CO2 by application of a simple rebreathing device resulted in improvement of abnormal blood gases and elimination of the Cheyne-Stokes-like respiratory pattern of the Rett syndrome. Near normalization of the EEG occurred when a normal respiratory pattern was imposed by means of a respirator. Taken together, these results lead to the preliminary conclusion that cerebral hypoxemia secondary to abnormal respiratory function may contribute to diminished production of biogenic amines in Rett syndrome.

Pelligra, R.↗
NASA NTRS1920

Tests of artificial flight at high altitudes

If we wish to form an accurate idea of the extraordinary progress achieved in aeronautics, a comparison must be made of the latest altitude records and the figures regarded as highest attainable limit some ten years ago. It is desirable, for two reasons, that we should be able to define the limit of the altitudes that can be reached without artificial aid. First, to know to what extent the human body can endure the inhalation of rarified air. Second, the mental capacity of the aviator must be tested at high altitudes and the limit known below which he is able to make reliable observations without being artificially supplied with oxygen. A pneumatic chamber was used for the most accurate observations.

Gradenwitz, Arthur↗
NASA NTRS1993

Respiratory Protection Program medical clearance for respirator use

Background on occupational exposure to various inhalents is discussed including on-site hazard control measures, procedures, physiological effects, and interpretation of results for the medical clearance of employee for use of personal respiratory protection devices. The purpose of the Respiratory Protection Program at LeRC is outlined, and the specifics of the Medical Surveillance Program for Respiratory Protection at LeRC are discussed.

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NASA NTRS1994

Gravity, the third dimension of life support in space

The ascent of the human into high altitudes required a 2-D life support system that supplied: oxygen, and heat. At lower altitudes, increased oxygen concentration in the inhaled gases was useful, but at higher altitudes for longer durations, this 'clever' life support approach was no longer adequate--physiologic requirements had to provide a natural pressure-based environment. In space, the life support system requires a third dimension, gravity. Although substituting for gravity has been successful on a limited number of physiologic functions for short-duration stays in space, long durations will require the effects of the real thing for critical physiologic functions. It has been known for over a hundred years that the forces of acceleration (G) and gravity are equivalent. Therefore, gravitational stimulation in space can be achieved with centrifugation. However, for this stimulation to be effective, the dosage of G required to maintain normal physiologic function must be determined. An approximation of this dosage of G for the human can be determined with 3-day bed-rest studies including periodic centrifuge exposure. Recent research on this topic is reviewed.

Burton, Russell R.↗
NASA NTRS1995

Development of an in-line filter to prevent intrusion of NO2 toxic vapors into A/C systems

The hypergolic propellant nitrogen tetroxide (N2O4 or NTO) is routinely used in spacecraft launched at Kennedy Space Center (KSC) and Cape Canaveral Air Station (CCAS). In the case of a catastrophic failure of the spacecraft, there would be a release of the unspent propellant in the form of a toxic cloud. Inhalation of this material at downwind concentrations which may be as high as 20 parts per million (ppm) for 30 minutes in duration, may produce irritation to the eyes, nose and respiratory tract. Studies at both KSC and CCAS have shown that the indoor concentrations of N2O4 during a toxic release may range from 1 to 15 ppm and depend on the air change rate (ACR) for a particular building and whether or not the air conditioning (A/C) system has been shut down or left in an operating mode. This project was initiated in order to assess how current A/C systems could be easily modified to prevent personnel from being exposed to toxic vapors. A sample system has been constructed to test the ability of several types of filter material to capture the N2O4 vapors prior to their infiltration into the A/C system. Test results will be presented which compare the efficiencies of standard A/C filters, water wash systems, and chemically impregnated filter material in taking toxic vapors out of the incoming air stream.

Meneghelli, Barry↗
NASA NTRS1997

A Summary of Ambient Air at John F. Kennedy Space Center with a Comparison to Data from the Florida Statewide Monitoring Network (1983-1992)

The EPA criteria air pollutants were monitored at Kennedy Space Center (KSC) since 1983 to comply the prevention of significant deterioration requirements under the Clean Air Act amendments passed by Congress in 1977 and 1990. Monitoring results show that monthly maximum 24-hour total suspended particulates decreased from 144.6 micograms/cu m in 1988 to 73.0 micrograms/cu m in 1991 and increased to 149.3 micrograms/cu m in 1992. Inhalable particulates increased from 56.1 gg/M3 in 1983 to 131.4 micrograms/cu m in 1988, and then decreased to 38.5 micrograms/cu m in 1992. Sulfur dioxide monthly maximum 24-hour average concentrations decreased each year from 135.2 micrograms/cu m in 1983 to 33.8 micrograms/cu m in 1992. Nitrogen dioxide concentrations increased from 5.1 micrograms/cu m in 1983 to 5.9 micrograms/cu m in 1988, then decreased to 4.5 micrograms/cu m in 1992. Carbon monoxide annual average concentrations decreased from 6.2 micrograms/cu m in 1983 to 1.1 micrograms/cu m in 1988, and increased to 1.2 micrograms/cu m in 1992. Ozone maximum 1-hour concentrations increased from 98 parts per billion (ppb) in 1983 to 134 ppb in 1989, and then decreased to 80 ppb in 1992. Total annual rainfall ranged from 37.47 inches to 57.47 inches and shows a 6.6 percent increase over this same ten year period.

Drese, John H.↗
NASA NTRS2001

COSMIC: Carbon Monoxide and Soot in Microgravity Inverse Combustion

Almost seventy percent of deaths in accidental fires are caused by inhalation of toxins such as carbon monoxide (CO) and smoke (soot) that form during underventilated burning. The COSMIC project examines the formation mechanisms of CO and soot during underventilated combustion, achieved presently using laminar, inverse diffusion flames (IDFs) formed between an air jet and surrounding fuel. A major hypothesis of the project is that the IDF mimics underventilated combustion because carbon-containing species that form on the fuel side of the flame (such as CO and soot) can escape without passing through an oxidizing flame tip. An IDF literature review was presented at the last microgravity workshop, and a few additional IDF papers have appeared since that meeting. The COSMIC project is entering the third year of its four-year funding cycle. The first two years have been devoted to designing and constructing a rig for use in the NASA 2.2-second drop tower. A few computations and laboratory experiments have been performed. The goals of this paper are to discuss the use of numerical simulation during burner design, to present computational and experimental results that support the hypothesis that IDFs are similar to underventilated flames, and to delineate future plans.

Blevins, L. G.↗
NASA NTRS1987

Particle Sizer

Microspheres are tiny plastic beads that represent the first commercial products manufactured in orbit. An example of how they are used is a new aerodynamic particle sizer designated APS 33B produced by TSI Incorporated. TSI purchased the microspheres from the National Bureau of Standards which certified their exact size and the company uses them in calibration of the APS 33B* instrument, latest in a line of TSI systems for generating counting and weighing minute particles of submicron size. Instruments are used for evaluating air pollution control devices, quantifying environments, meteorological research, testing filters, inhalation, toxicology and other areas where generation or analysis of small airborne particles is required. * The APS 33B is no longer being manufactured. An improved version, APS 3320, is now being manufactured. 2/28/97

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NASA NTRS1985

Lung Diagnosis

NASA research in aircraft sound production provided a theoretical basis for a mode of the production of human respiratory sounds. Respiratory changes that occur after inhaling cigarette smoke may be recorded and analyzed. The research team includes representatives from the Medical College of Virginia, RTI, Bruel and Kjaer Instruments. A commercial market as a diagnostic tool is anticipated.

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