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Allen, J.

Publications and source records attributed to Allen, J..

47 records · Page 3
All sourcesNASA NTRSDOE OSTI
NASA NTRS1991

Global Change Encyclopedia - A project for the international space year

'Global Change Encyclopedia' is a project for the International Space Year in 1992. The project will produce a comprehensive set of satellite and other global data with relevance to studies of global change and of the earth as a system. These data will be packaged on CD-ROMs, accompanied by appropriate software for access, display and manipulation. On behalf of the Canadian Space Agency, the project is being carried out by the Canada Centre for Remote Sensing, with the U.S. National Oceanic and Atmospheric Administration and the U.S. National Aeronautics and Space Administration as major contributors. This paper highlights the background leading to the project, the concept and principal characteristics of the Encyclopedia itself, and the current status and plans.

Cihlar, J.↗
NASA NTRS1982

Advanced ceramic coating development for industrial/utility gas turbine applications

The effects of ceramic coatings on the lifetimes of metal turbine components and on the performance of a utility turbine, as well as of the turbine operational cycle on the ceramic coatings were determined. When operating the turbine under conditions of constant cooling flow, the first row blades run 55K cooler, and as a result, have 10 times the creep rupture life, 10 times the low cycle fatigue life and twice the corrosion life with only slight decreases in both specific power and efficiency. When operating the turbine at constant metal temperature and reduced cooling flow, both specific power and efficiency increases, with no change in component lifetime. The most severe thermal transient of the turbine causes the coating bond stresses to approach 60% of the bond strengths. Ceramic coating failures was studied. Analytic models based on fracture mechanics theories, combined with measured properties quantitatively assessed both single and multiple thermal cycle failures which allowed the prediction of coating lifetime. Qualitative models for corrosion failures are also presented.

Andersson, C. A.↗
NASA NTRS1981

Comparison of two parallel/series flow turbofan propulsion concepts for supersonic V/STOL

The thrust, specific fuel consumption, and relative merits of the tandem fan and the dual reverse flow front fan propulsion systems for a supersonic V/STOL aircraft are discussed. Consideration is given to: fan pressure ratio, fan air burning, and variable core supercharging. The special propulsion system components required are described, namely: the reflecting front inlet/nozzle, the aft subsonic inlet, the reverse pitch fan, the variable core supercharger and the low pressure forward burner. The potential benefits for these unconventional systems are indicated.

Luidens, R. W.↗
NASA NTRS1981

Comparison of two parallel/series flow turbofan propulsion concepts for supersonic V/STOL

The thrust, specific fuel consumption, and relative merits of the tandem fan and the dual reverse flow front fan propulsion systems for a supersonic V/STOL aircraft are discussed. Consideration is given to: fan pressure ratio, fan air burning, and variable core supercharging. The special propulsion system components required are described, namely: the deflecting front inlet/nozzle, the aft subsonic inlet, the reverse pitch fan, the variable core supercharger and the low pressure forward burner. The potential benefits for these unconventional systems are indicated.

Luidens, R. W.↗
NASA NTRS1977

Living and working in space

The feasibility of space colonization depends partly on the answer to the practical question whether construction workers can exist and work in zero-g for the time necessary to build the colony framework to the point just prior to spinning it into its artificial-g mode. Based on definitive Skylab experience, there seems to be every reason to believe that workers in zero-g can perform their construction tasks with the same skill as under 1-g conditions. Attention is also given to basic reasons and motivations for the conduction of space flights and the establishment of space colonies.

Allen, J.↗