20,128 research outputs found
Mechanically limited, electrically operated hydraulic valve system for aircraft controls Patent
Development of aircraft control system with high performance electrically controlled and mechanically operated hydraulic valves for precise flight operatio
Laser vibration analyzer
Instrument system uses laser and optical heterodyne receiver to measure Doppler phase shifts produced on a laser beam by the deflection of the vibrating surface of a structure under test or in operation
Autonomous Guidance Algorithms for NASA Learn-to-Fly Technology Development
Learn-to-Fly (L2F) is an advanced technology development effort under the NASA Transformative Aeronautics Concepts Program (TACP) that is aimed at assessing the feasibility of self-learning flight vehicles. Specifically, research has been conducted to demonstrate the potential to merge two enabling technologies; real-time aerodynamic modeling and adaptive controls, to substantially reduce the typical ground and flight testing requirements for air vehicle design. The approach to this effort involved development of unique airframes and on-board algorithms to demonstrate key L2F technologies on a fully autonomous flight test vehicle. This research, that included an aggressive flight test program, was intended to rapidly advance these technologies and demonstrate capabilities of the L2F approach. Key components of the L2F architecture include real-time aerodynamic modeling, adaptive controls and control allocation, and guidance. This paper provides an overview of the guidance algorithm which primarily served as an executive function to coordinate control commands for range navigation and the desired test conditions, provide autonomous envelope limiting/expansion and enable automatic landing to touchdown with no intervention from a human operator. A discussion of the L2F concept-of-operations and unique flight testing considerations, which influenced the guidance functional requirements, is included and results of recent flight testing are presented
EFFECTS OF SPOILER-SLOT-DEFLECTOR CONTROL ON THE AERODYNAMIC CHARACTERISTICS AT A MACH NUMBER OF 2.01 OF A VARIABLE-WINGSWEEP CONFIGURATION WITH THE OUTER WING PANELS SWEPT BACK 75 DEG
Aerodynamic characteristics of variable-wing-sweep configuration with spoiler-slot-deflector control system & swept back outer wing panel
EFFECTS OF WING VERTICAL LOCATION ON THE STABILITY AND CONTROL CHARACTERISTICS AT A MACH NUMBER OF 2.01 OF A CANARD AIRPLANE CONFIGURATION WITH A TRAPEZOIDAL ASPECT-RATIO-3 WING
Effects of wing vertical location on stability and control of canard aircraft at supersonic speed
Extraction and utilization of space acquired physiographic data for water resources development
ERTS-1 satellite imagery was evaluated as a means of providing useful watershed physiography information. From these data physiographic parameters such as drainage basin area and shape, drainage density, stream length and sinuosity, and the percentage of a watershed occupied by major land use types were obtained in three study areas. The study areas were: (1) Southwestern Wisconsin; (2) Eastern Colorado, and (3) portions of the Middle Atlantic States. Using ERTS-1 imagery at 1:250,000 and 1:100,000 scales it was found that drainage basin area and shape and stream sinuosity were comparable (within 10%) in all study areas to physiographic measurements derived from conventional topographic maps at the same scales
ECONOMIC ANALYSIS OF PHOSPHORUS - REDUCING TECHNOLOGIES IN PORK PRODUCTION
Soil phosphorus levels have increased as pork production has become concentrated. Phosphorus-based manure management regulations for land application have been proposed by policy makers. The objective of this study is to determine benefits/costs of adopting two alternatives for reducing phosphorus: synthetic amino acids or phytase. An optimization model is constructed to determine optimal excreted nitrogen and phosphorus from alternative feed ingredients. Results are derived using different manure storage and application systems. While the two alternatives are not least-cost ingredients, they become profitable when producers are constrained by land. An important result is that the net cost of manure is negative.Livestock Production/Industries,
NUTRITION AND THE ECONOMICS OF SWINE MANAGEMENT
Current methods of formulating animal rations lead to excess nutrient excretion which can potentially lead to excess manure nutrients and an increase in economic costs. These methods do not recognize the impact of diminishing returns. The objective is to simultaneously optimize feed ration composition and replacement. The results, when compared against results from a survey of feed companies, indicate that using a profit maximization rather than live weight growth maximization criterion targets nutrients to an animal's actual needs and, hence, fewer nutrients are excreted and higher returns for producers are obtained.nonlinear growth modeling, pigs, replacement, swine, Livestock Production/Industries,
Rank and null space calculations using matrix decomposition without column interchanges
AbstractThe most widely used stable methods for numerical determination of the rank of a matrix A are the singular value decomposition and the QR algorithm with column interchanges. Here two algorithms are presented which determine rank and nullity in a numerically stable manner without using column interchanges. One algorithm makes use of the condition estimator of Cline, Moler, Stewart, and Wilkinson and relative to alternative stable algorithms is particularly efficient for sparse matrices. The second algorithm is important in the case that one wishes to test for rank and nullity while sequentially adding columns to a matrix
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