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Results for “Ecological Systems, Closed”

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At least 19 recordsLinked to original sources
PubMedDate not supplied

[Model of an ecological system closed as regards gas metabolism and with a periodically working autotrophic component. I. Conditions for stability of the atmospheric system].

The paper describes a semi-closed ecological system consisting of a man and a photosynthetic autotrophic component. The conditions required to maintain the stability of the atmosphere in the system are described as applied to two alternating modes of the function of the autotrophic component. These conditions express equal quantities of oxygen and carbon dioxide consumed and produced by the components of the system during any time period the length of which is the duration of the cycle of the system. On this basis equations have been derived which help to identify the photosynthetic cultures that can be used as an autotrophic component in a closed man-sustaining life support system.

Ecological Systems, Closed↗
PubMed1975

Microbiological sampling of the spacecraft atmosphere during a simulated skylab mission.

A skylab Air Sampler (SAS) has been developed for the use during Skylab missions. The SAS was used in the Skylab Medical Experiments Altitude Test (SMEAT) to gather baseline data which could be directly compared to data obtained during actual Skylab missions. The results obtained in the SMEAT gave no evidence of consistent change in either concentration or types of microorganisms in the SMEAT atmosphere over the 56-d test. Microorganisms found included some potential pathogens but were largely normal human microflora. Few typical soil microorganisms were found. These findings are related to commonly anticipated effects of long-term spaceflights on environmental microflora and to other closed environment studies.

Aerospace Medicine↗
PubMedDate not supplied

[Model of an ecosystem closed as regards gas metabolism and with a periodically working autotrophic component. II. Stability of the periodic cycles].

The literature data concerning the effect of the atmosphere composition on the photosynthetic productivity of an intensive microalgal culture were used to build a mathematical model of a semiclosed ecological system working in the light-dark alternating cycles. The type of the relationship between time cycles and composition of the stationary atmosphere of the ecological system has been established. The conditions of the existence and stability of the stationary atmosphere have been determined.

Ecological Systems, Closed↗
PubMedDate not supplied

[Composition of the trace contaminants in the atmosphere of the Soiuz-22 space ship].

The Soyuz-22 space cabin atmosphere was studied for volatile organic trace contaminants. By gas chromatography the following constituents were identified: methane, ethane, heptane, methanol, ethanol, n-propanol, acetaldehyde, acetone, ethyl benzene. Except for acetone, concentrations of the above compounds were close to the values determined in the mock-up experiments.

Air Pollutants↗
PubMed1975

The effects of cosmic particle radiation on pocket mice aboard Apollo XVII: IV. engineering aspects of the experiment and results of animal tests.

A closed passive system independent of support from the spacecraft or its crew was developed to house five pocket mice for their flight on Apollo XVII. The reaction of potassium superoxide with carbon dioxide and water vapor to produce oxygen provided a habitable atmosphere within the experiment package. The performance of the system and the ability of the mice to survive the key preflight tests gave reasonable assurance that to mice would also withstand the Apollo flight.

Animals↗
PubMedDate not supplied

[Variants of the control over a gas-exchange closed ecosystem with a periodically operating autotrophic component].

The paper discusses the problem of how to control a gas exchange closed ecosystem that consists of autotrophic and heterotrophic components and operates periodically in the light or in the dark. The purpose of the control is to maintain the steady state of an ecosystem with a man-oriented atmosphere. This problem of control has different solutions each of which is characterized by a set of six dimensionless variables associated with three equations--steady-state conditions. The physical characteristics of the variables and conditions of similarity of ecosystems are described. The resultant methods of control are evaluated from the point of view of economic operation of the ecosystem and the level of stability of its amosphere. The class of ecosystems for which the results obtained are valid in the event of accidental perturbations is presented.

Air↗
PubMed1978

Mycological profile of crew during 56-day simulated orbital flight.

Mycological analyses were made on specimens obtained from the skin, oral rinse, urine, and feces of three subjects participating in a 56 day Skylab simulation test. Samples were taken over a 175 day period divided into three phases consisting of a prechamber, intrachamber, and postchamber period. A total of 69 species of filamentous fungi and 22 species of yeast and yeast-like fungi were recovered and identified. There was a marked decrease in the isolation incidence of both the filamentous and yeast and yeast-like fungi during the intrachamber period. This, taken with the fact that 71% of the filamentous species and 55% of the yeast and yeast-like species were isolated no more than twice, reflects the transitory nature of the relationship between the human body and most fungi. However, there was a relative increase in the potential pathogens Candida albicans and Candida parapsilosis during the intrachamber period. Over 50% of all fungi recovered were isolated from the nasal and oral cavities. There was no evidence of intercrew transfer of a particular species during the intrachamber period nor was there any evidence of microbial shock during the postchamber period.

Adult↗
PubMed1978

Update '77.

Explore the source record for details and available documents.

Animals↗
PubMed1978

Prevalence of fungi during Skylab missions.

Samples for mycological analysis were collected from surfaces in the Skylab spacecraft before launch and during flight for each manned mission. Fungal contamination levels were low during the first two flights; however, the species recovered were different for each mission. On the third mission, widespread contamination of the Skylab spacecraft with Aspergillus and Pencillium spp. was detected. This contamination was traced to several contaminated space suit undergarments.

Aspergillus↗
PubMed1977

The effect of Skylab on the chemical composition of saliva.

The levels of specific proteins and electrolytes in stimulated whole saliva were monitored in Skylab crew members before and after each mission. With few exceptions, mission-associated compositional changes in saliva were relatively minimal. There were no changes in(formula see text), Cl-, albumin, or IgG concentrations. There were slight decreases in total protein coinciding with moderate saliva flow rate increases immediately before and after each flight. Other changes included diminutions in Na+ and lysozyme, and elevations in Mg++ and IgA. The IgA increase was the most pronounced mission-associated change observed.

Adult↗