Variable-cycle engines for supersonic cruise aircraft

Progress and the current status of the Variable Cycle Engine (VCE) study are reviewed with emphasis placed on the impact of technology advancements and design specifications. A large variety of VCE concepts are also examined

General aviation energy-conservation research programs at NASA-Lewis Research Center

The major thrust of NASA's nonturbine general aviation engine programs is directed toward (1) reduced specific fuel consumption, (2) improved fuel tolerance; and (3) emission reduction. Current and planned future programs in such areas as lean operation, improved fuel management, advanced cooling techniques and advanced engine concepts, are described. These are expected to lay the technology base, by the mid to latter 1980's, for engines whose total fuel costs are as much as 30% lower than today's conventional engines

Development potential of Intermittent Combustion (I.C.) aircraft engines for commuter transport applications

An update on general aviation (g/a) and commuter aircraft propulsion research effort is reviewed. The following topics are discussed: on several advanced intermittent combustion engines emphasizing lightweight diesels and rotary stratified charge engines. The current state-of-the-art is evaluated for lightweight, aircraft suitable versions of each engine. This information is used to project the engine characteristics that can be expected on near-term and long-term time horizons. The key enabling technology requirements are identified for each engine on the long-term time horizon

INSTITUTIONAL AFFILIATION OF AUTHORS IN THE AMERICAN JOURNAL OF AGRICULTURAL ECONOMICS, 1988-1992

Opaluch and Just reported the top 20 departments in pages per faculty of articles in the American Journal of Agricultural Economics for the five year period 1968-1972. To determine how much has changed and how much has not during the intervening two decades, the analysis was repeated for the five year period 1988-1992. Some things seem not to change. University of California, Berkeley, remains at the pinnacle twenty years later. And 13 of the top 20 departments two decades ago, remain there during the 1988-1992 period. But seven did change, and the most notable aspect is that the number of Northeast departments in the top 20 rose from two to five.Teaching/Communication/Extension/Profession,

GEOGRAPHIC INFORMATION SYSTEMS AND APPLIED ECONOMICS: AN INITIAL DISCUSSION OF POTENTIAL APPLICATIONS AND CONTRIBUTIONS

Geographic Information Systems (GIS) are becoming increasingly important to virtually all of the natural and social sciences. Applied economists will find that GIS can make valuable contributions to many of the problems with which they are concerned. Moreover, a great deal of the science behind GIS technology would benefit from the contributions of applied economists. This paper presents some initial suggestions for the ways in which GIS may be important to economics and the GIS related issues concerning which applied economists could provide useful insights.Research and Development/Tech Change/Emerging Technologies,

Computational experience with a three-dimensional rotary engine combustion model

A new computer code was developed to analyze the chemically reactive flow and spray combustion processes occurring inside a stratified-charge rotary engine. Mathematical and numerical details of the new code were recently described by the present authors. The results are presented of limited, initial computational trials as a first step in a long-term assessment/validation process. The engine configuration studied was chosen to approximate existing rotary engine flow visualization and hot firing test rigs. Typical results include: (1) pressure and temperature histories, (2) torque generated by the nonuniform pressure distribution within the chamber, (3) energy release rates, and (4) various flow-related phenomena. These are discussed and compared with other predictions reported in the literature. The adequacy or need for improvement in the spray/combustion models and the need for incorporating an appropriate turbulence model are also discussed