Thrust reverser for a long duct fan engine

A bypass duct outer cowl includes a fixed cascade disposed between axially spaced fixed cowl portions and a translatable cowl sleeve and blocker doors movably disposed on the respective radially outer and inner sides of the cascade. Actuation and linkage structure located entirely within the outer cowl provides for selectively moving the cowl sleeve rearwardly and rotating the blocker doors to a position across the bypass duct to cause the fan airflow to pass through the cascade in a thrust reversing manner

Signal processor architecture for backscatter radars

Real time signal processing for backscatter radars which requires computational throughput and I/O rates is discussed. The operations that are usually performed in real time are highly repetitive simple accumulations of samples or of products of samples. The control logic does not depend on the values of the data and general purpose computers are not required for the initial high speed processing. The implications of these facts on the architectures of preprocessors for backscatter radars are explored and applied to the design of the Radar Signal Compender

Feasibility of conventional control techniques for large highly coupled elastic boost vehicles Final report

Control techniques for large highly-coupled elastic boost vehicles with elastic and fuel slosh mode frequencies close to desired control frequencies - motion equation

Data management study, volume 5. Appendix B - Contractor data package Planetary Quarantine /PQ/ Final report

Contractor data management package for Voyager spacecraft sterilization projec

The neutral gas in the environs of the Geminga gamma-ray pulsar

We present a high-resolution (24 arcsec) study of the HI interstellar gas distribution around the radio-quiet neutron star Geminga. Based on Very Large Array (VLA) and MPIfR Effelsberg telescope data, we analyzed a 40' x 40' field around Geminga. These observations have revealed the presence of a neutral gas shell, 0.4 pc in radius, with an associated HI mass of 0.8 Msun, which surrounds Geminga at a radial velocity compatible with the kinematical distance of the neutron star. In addition, morphological agreement is observed between the internal face of the HI shell and the brightest structure of Geminga's tail observed in X-rays.We explore the possibility that this morphological agreement is the result of a physical association.Comment: One tarfile including a Latex file (7 pages) and two figures. Paper accepted for publication in Advances in Space Research; typos corrected; changes in section Results and Discussion after referee's suggestions. S. Johnston's affilation correcte

Autonomous RPRV Navigation, Guidance and Control

Dryden Flight Research Center has the responsibility for flight testing of advanced remotely piloted research vehicles (RPRV) to explore highly maneuverable aircraft technology, and to test advanced structural concepts, and related aeronautical technologies which can yield important research results with significant cost benefits. The primary purpose is to provide the preliminary design of an upgraded automatic approach and landing control system and flight director display to improve landing performance and reduce pilot workload. A secondary purpose is to determine the feasibility of an onboard autonomous navigation, orbit, and landing capability for safe vehicle recovery in the event of loss of telemetry uplink communication with the vehicles. The current RPRV approach and landing method, the proposed automatic and manual approach and autoland system, and an autonomous navigation, orbit, and landing system concept which is based on existing operational technology are described

Wheat for Profit

Wheat ranks as one of the important agricultural products of South Dakota. The soil and climatic conditions are favorable for the production of high quality wheats. Other factors are the choice of varieties, good cultural methods, crop rotation and the control of diseases

Is there an Income Gradient in Child Health? It depends whom you ask

A large literature uses parental evaluations of child health status to provide evidence on the socioeconomic determinants of health. If how parents perceive health questions differs by income or education level, then estimates of the socioeconomic gradient are likely to be biased and potentially misleading. In this paper we examine this issue. We directly compare child mental health evaluations from parents, teachers, children and psychiatrists for mental health problems, test whether these differences are systematically related to observable child and parent characteristics, and examine the implications of the different reports for the estimated income gradient. We find that respondents frequently evaluate children differently and while the sign of the income gradient is in the same direction across respondents, systematic differences in evaluations mean that the estimated magnitude and significance of the health-income gradient is highly dependent upon the choice of respondent and the measure of child health.Child Health, Income, Reporting Bias