The NASA Lewis large wind turbine program

The program is directed toward development of the technology for safe, reliable, environmentally acceptable large wind turbines that have the potential to generate a significant amount of electricity at costs competitive with conventional electric generation systems. In addition, these large wind turbines must be fully compatible with electric utility operations and interface requirements. Advances are made by gaining a better understanding of the system design drivers, improvements in the analytical design tools, verification of design methods with operating field data, and the incorporation of new technology and innovative designs. An overview of the program activities is presented and includes results from the first and second generation field machines (Mod-OA, -1, and -2), the design phase of the third generation wind turbine (Mod-5) and the advanced technology projects. Also included is the status of the Department of Interior WTS-4 machine

Diffraction-limited CCD imaging with faint reference stars

By selecting short exposure images taken using a CCD with negligible readout noise we obtained essentially diffraction-limited 810 nm images of faint objects using nearby reference stars brighter than I=16 at a 2.56 m telescope. The FWHM of the isoplanatic patch for the technique is found to be 50 arcseconds, providing ~20% sky coverage around suitable reference stars.Comment: 4 page letter accepted for publication in Astronomy and Astrophysic

The development and interchange of navigational information and technology between the maritime communities of Iberia, North-Western Europe and Asia, 1500-1620

This thesis examines the development of navigational technology and its subsequent transmission through various means to the emergent maritime powers of Northwestern Europe. Since the fifteenth century the Portuguese, and to a lesser extent the Castillians had sought to impose a bureaucratic system of commercial security to prevent the exploitation by foreigners of the technical and cartographic knowledge available within their hydrographical agencies, navigation schools, and official trading monopolies. Some controversies over this are reviewed, but it is concluded that the most important feature of this technology was its international nature, even though until the 1540's this was disguised by Iberian security. This meant Portuguese sailors could share in a productive series of technical interchanges with Asian mariners after 1500.Possibly by the late sixteenth century they had come to rely too heavily on Asian information, Luso-Asian cartographers, and Asian pilots. This meant that once Northern Europe; powers had obtained translations of Iberian navigation manuals, and taken Iberian experts into their service, they could quickly attain such proficiency as to sail directly into Asian or Pacific waters and themselves participate in similar interchanges. This proved significant technically and politically because the Iberians were unable to place an effective security blanket on the interchange of navigational information in Asia. Asian waters had been typified by some long -standing traditions of relatively free interchange of such technology between seamen of different civilisations. Just as this mutually enriched Asian traditions, so it was also exploited by the Iberians and later European rivals. These interchanges are examined in chapters on the Arab, Indian, Indonesia, Pacific, Chinese, and Japanese interchanges. They hastened the development of a world economy, and the decline of the sixteenth century Portuguese Empire and monopoly of Asia's oceanic trade

Large wind turbines: A utility option for the generation of electricity

The wind resource is such that wind energy generation has the potential to save 6-7 quads of energy nationally. Thus, the Federal Government is sponsoring and encouraging the development of cost effective and reliable wind turbines. One element of the Federal Wind Energy Programs, Large Horizontal Axis Wind Turbine Development, is managed by the NASA Lewis Research Center for the Department of Energy. There are several ongoing wind system development projects oriented primarily toward utility application within this program element. In addition, a comprehensive technology program supporting the wind turbine development projects is being conducted. An overview is presented of the NASA activities with emphasis on application of large wind turbines for generation of electricity by utility systems

Large wind turbines: A utility option for the generation of electricity

The economic and technical potential of wind energy in the United States is discussed. Particular attention is given to the status of wind turbine operational experience as well as the environmental posture of the technology

On-board timeline validation and repair : a feasibility study

We report on the progress and outcome of a recent ESAfunded project (MMOPS) designed to explore the feasibility of on-board reasoning about payload timelines. The project sought to examine the role of on-board timeline reasoning and the operational context into which it would fit. We framed a specification for an on-board service that fits with existing practices and represents a plausible advance within sensible constraints on the progress of operations planning. We have implemented a prototype to demonstrate the feasibility of such a system and have used it to show how science gathering operations might be improved by its deployment

Suppression of combustion oscillations with mechanical devices Interim report

Static rocket thrust chamber simulator for cylindrical cold flow-type apparatus desig

Functional design for operational earth resources ground data processing

The author has identified the following significant results. Study emphasis was on developing a unified concept for the required ground system, capable of handling data from all viable acquisition platforms and sensor groupings envisaged as supporting operational earth survey programs. The platforms considered include both manned and unmanned spacecraft in near earth orbit, and continued use of low and high altitude aircraft. The sensor systems include both imaging and nonimaging devices, operated both passively and actively, from the ultraviolet to the microwave regions of the electromagnetic spectrum

Symbolic computation of exact solutions expressible in hyperbolic and elliptic functions for nonlinear PDEs

Algorithms are presented for the tanh- and sech-methods, which lead to closed-form solutions of nonlinear ordinary and partial differential equations (ODEs and PDEs). New algorithms are given to find exact polynomial solutions of ODEs and PDEs in terms of Jacobi's elliptic functions. For systems with parameters, the algorithms determine the conditions on the parameters so that the differential equations admit polynomial solutions in tanh, sech, combinations thereof, Jacobi's sn or cn functions. Examples illustrate key steps of the algorithms. The new algorithms are implemented in Mathematica. The package DDESpecialSolutions.m can be used to automatically compute new special solutions of nonlinear PDEs. Use of the package, implementation issues, scope, limitations, and future extensions of the software are addressed. A survey is given of related algorithms and symbolic software to compute exact solutions of nonlinear differential equations.Comment: 39 pages. Software available from Willy Hereman's home page at http://www.mines.edu/fs_home/whereman