8,280 research outputs found
Transpirationally cooled heat ablation system Patent
Transpirationally cooled heat ablation system for interplanetary spacecraft reentry shieldin
Conducting a Self-Assessment of a Long-Term Archive for Interdisciplinary Scientific Data as a Trustworthy Digital Repository
4th International Conference on Open RepositoriesThis presentation was part of the session : Conference PresentationsDate: 2009-05-19 03:00 PM – 04:30 PMLong-term preservation and stewardship of scientific data and research-related information is paramount to the future of science and scholarship. Disciplinary and interdisciplinary scientific data archives can offer capabilities for managing and preserving data for research, education, and decision-making activities of future communities representing various scientific and scholarly disciplines. However, meeting the requirements for a trusted digital repository presents challenges to ensure that archived collections will be discoverable, accessible, and usable in the future. Assessing whether scientific data archives meet the requirements for trustworthy repositories will help to ensure that todayâ s collections of scientific data will be available in the future. A continuing self-assessment of a long-term archive for interdisciplinary scientific data is being conducted to identify improvements needed to become a trustworthy repository for managing and providing access to interdisciplinary scientific data by future communities of users. Recommendations are offered for archives of scientific data to meet the requirements of a trustworthy repository.NAS
Space Transportation System/Cargo Mass Properties Calculation Using an Interactive System
The methodology used to perform STS cargo mass properties calculations using an interactive computer system is described
Planetary radar
The radar astronomy activities supported by the Deep Space Network are reported. The high power S- and X-band radar transmitters at the Goldstone 64 meter station were used for a radar probe of Mars during January, February, and March 1980, which was designed to provide range and Doppler data derived from signals reflected from the Martian surface, taking advantage of the planet's nearness during opposition
Research study for gel precursors as glass and ceramic starting materials for space processing applications research
The development of techniques for the preparation of glass and ceramic starting materials that will result in homogeneous glasses or ceramic products when melted and cooled in a containerless environment is described. Metal-organic starting materials were used to make compounds or mixtures which were then decomposed by hydrolysis reactions to the corresponding oxides. The sodium tungstate system was chosen as a model for a glass with a relatively low melting temperature. The alkoxide tungstates also have interesting optical properties. For all the compositions studied, comparison samples were prepared from inorganic starting materials and submitted to the same analyses
Glass shell manufacturing in space
Residual gases always found in glass shells are CO2, O2 and N2. In those cases where high water vapor pressure is maintained in the furnace, water is also found in the shells. Other evidence for the existence of water in shells is the presence of water-induced surface weathering of the interior shell surface. Water and CO2 are the predominant volatiles generated by the pyrolysis of both inorganic and hydrolyzed metal-organic gels. The pyrolysates of unhydrolyzed metal-organic gels also contain, in addition to water and CO2, significant levels of organic volatiles, such as ethanol and some hydrocarbons; on complete oxidation, these produce CO2 and water as well. Water is most likely the initial blowing agent, it is produced copiously during the initial stages of heating. In the later stages, CO2 becomes the dominant gas as H2O is lost at increasing rates. Water in the shell arises mainly from gel dehydration, CO2 by sodium bicarbonate/carbonate decomposition and carbon oxidation, and O2 and N2 by permeation of the ambient furnace air through the molten shell wall
Using permeable membranes to produce hydrogen and oxygen from water
Concept may make it profitable to obtain hydrogen fuel from water. Laboratory tests have demonstrated that method enables decomposition of water several orders of magnitude beyond equilibrium state where only small amounts of free hydrogen are present
Indigenous vegetation types of Hamilton Ecological District
The following descriptions of indigenous vegetation types and lists of the most characteristic species have been compiled for the major landform units of the Hamilton Ecological District, which lies within the Waikato Ecological Region (McEwen 1987). The boundaries of the Hamilton Ecological District correspond approximately to those of the Hamilton basin, with the addition of parts of hills and foothills at the margins of the basin. The vegetation descriptions and species lists are based on knowledge of the flora of vegetation remnants in the ecological district, historical records (e.g., Gudex 1954), and extrapolation of data from other North Island sites with similar environmental profiles
Glass shell manufacturing in space
Highly-uniform, hollow glass spheres (shells), which are used for inertial confinement fusion targets, were formed from metal-organic gel powder feedstock in a vertical furnace. As a result of the rapid pyrolysis caused by the furnace, the gel is transformed to a shell in five distinct stages: (a) surface closure of the porous gel; (b) generation of a closed-cell foam structure in the gel; (c) spheridization of the gel and further expansion of the foam; (d) coalescence of the closed-cell foam to a single-void shell; and (e) fining of the glass shell. The heat transfer from the furnace to the falling gel particle was modeled to determine the effective heating rate of the gel. The model predicts the temperature history for a particle as a function of mass, dimensions, specific heat, and absorptance as well as furnace temperature profile and thermal conductivity of the furnace gas. A model was developed that predicts the gravity-induced degradation of shell concentricity in falling molten shells as a function of shell characteristics and time
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