7,908 research outputs found
Flight investigation of insect contamination and its alleviation
An investigation of leading edge contamination by insects was conducted with a JetStar airplane instrumented to detect transition on the outboard leading edge flap and equipped with a system to spray the leading edge in flight. The results of airline type flights with the JetStar indicated that insects can contaminate the leading edge during takeoff and climbout. The results also showed that the insects collected on the leading edges at 180 knots did not erode at cruise conditions for a laminar flow control airplane and caused premature transition of the laminar boundary layer. None of the superslick and hydrophobic surfaces tested showed any significant advantages in alleviating the insect contamination problem. While there may be other solutions to the insect contamination problem, the results of these tests with a spray system showed that a continouous water spray while encountering the insects is effective in preventing insect contamination of the leading edges
History of the numerical aerodynamic simulation program
The Numerical Aerodynamic Simulation (NAS) program has reached a milestone with the completion of the initial operating configuration of the NAS Processing System Network. This achievement is the first major milestone in the continuing effort to provide a state-of-the-art supercomputer facility for the national aerospace community and to serve as a pathfinder for the development and use of future supercomputer systems. The underlying factors that motivated the initiation of the program are first identified and then discussed. These include the emergence and evolution of computational aerodynamics as a powerful new capability in aerodynamics research and development, the computer power required for advances in the discipline, the complementary nature of computation and wind tunnel testing, and the need for the government to play a pathfinding role in the development and use of large-scale scientific computing systems. Finally, the history of the NAS program is traced from its inception in 1975 to the present time
Considerations regarding the evaluation and reduction of supersonic skin friction
Experimental and predicted data on turbulent boundary-layer skin friction of supersonic transport configuratio
A proto-campfire initiative in Mahenye Ward, Chipinge District: development of a wildlife utilization programme in response to community needs
A CASS Occasional paper on the management of Zimbabwe's wildlife and natural resources for the benefit of rural communities.Mahenye ward lies in the lowveld at the southeastern edge of Zimbabwe/ adjacent to Gonarezhou National Park which forms the wildlife resource base of the area. Beginning in 1982, Mahenye ward's wildlife utilization project preceded other similar projects in the country, demonstrating the possibility for communal area management of indigenous resources before Campfire became government policy. Mahenye's wildlife utilization project is unusual in the extent to which it developed without external support or technical assistance. It was essentially a local response to local needs based on local possibilities. It has attracted little attention compared with larger externally assisted and subsidized projects in Nyaminyami and Guruve Districts. The Mahenye story is much more fascinating in detail than this brief account can reflect. The author hopes he will be forgiven for the mistakes of over simplification and omission.
Primarily a one ward project, the Mahenye project remains relatively informally organized and operated. It is a pre- Campfire success in a district which has only recently developed a Campfire programme and which can be followed by other wards and districts. Mahenye has influenced an interest in Campfire in adjacent wards and districts, and proven that community support for wildlife can be strong and long lasting in-spite of lack of consistent support at the district level. The major problem experienced by the Mahenye wildlife utilization programme was first gaining and now maintaining the support of the district council. Mahenye is a success story which deserves careful attention because it raises the question of whether there is room in Campfire for ward-level success stories.The Ford Foundation & IDRC
IMPACT OF EXPORTS ON THE U.S. BEEF INDUSTRY
Policy and programmatic decisions dealing with beef exports require good information as to the impact of exports on the domestic beef industry. This paper utilizes a partial equilibrium model of the world beef market to assess the impacts on the U.S. beef sector of increases in real income in major beef importing countries, the impacts of changes in the prices of pork and poultry products, and the impacts of changes in the price of feedgrains. A one percent increase in real GDP in Canada, Japan, Mexico, and South Korea yielded a 1.6 percent increase in U.S. exports of high-quality beef. This increase in exports leads to approximately a 29.2 million pound increase U.S. beef production on a retail weight basis. The increase in export demand also yields an increase in beef prices of approximately 120 box of beef and 70 fed steer. One percent increases in the prices of pork and poultry products yield a smaller 0.8 percent increase in U.S. beef exports, but also lead to a 1.5 percent increase in U.S. imports of low-quality beef. This is due to U.S. consumers viewing low-quality beef as a substitute for pork and poultry. Finally, a one percent increase in the price of feedgrains reduces U.S. beef exports by 0.4 percent. This is due to a reduction in U.S. beef production from the increased feeding costs.International Relations/Trade, Livestock Production/Industries,
Investigation of the Properties of the Iterations of a Homeomorphism on a Metric Space
Considerable study has been made concerning the properties of the iterations of a homeomorphism on a metric space. Much of this material is scattered throughout the literature and understood solely by a specialist. The main object of this paper is to put into readable form proofs of theorems found in G.T. Whyburn\u27s Analytic Topology pertaining to this topic in topology. Properties of the decomposition space of point-orbits induced by the iterations of a homeomorphism will compose a major part of the study. Some theorems will be established through series of lemmas required to fill in much of the detail lacking in proofs found the book.
Although an elementary knowledge of topology is assumed throughout the paper, references are given for basic definitions and theorems used in developing some of the proofs.
The following symbols and notation will be used throughout the paper. X will denote a metric space with metric p, S a topological space, I the set of positive integers, A, B, C... sets of points or elements. Small letters, such as a, b, c, x, y, z... will designate elements or points of sets. U and V will denote open sets Sr(x) a spherical neighborhood of x with radius r. A\u27 denotes the set of limit points of A. A- the set of closure points of A/ U, N, C will denote union, intersection, and set inclusion respectively. The symbol E will mean is an element of . 0 denotes the empty set. S - A is the set of points in S which are not in A
Numerical Aerodynamic Simulation (NAS)
The history of the Numerical Aerodynamic Simulation Program, which is designed to provide a leading-edge capability to computational aerodynamicists, is traced back to its origin in 1975. Factors motivating its development and examples of solutions to successively refined forms of the governing equations are presented. The NAS Processing System Network and each of its eight subsystems are described in terms of function and initial performance goals. A proposed usage allocation policy is discussed and some initial problems being readied for solution on the NAS system are identified
Epilogue: Whales and Elephants as Cultural Symbols
... In his commentary, Dr. Peterson focuses on two of the papers presented in this volume, those by Ris and Kalland, who analyze the evolving symbolic significance of whales and how this has affected coastal whaling communities in northern Norway. As a discussant of the whaling papers at the Common Property Conference, Dr. Peterson was impressed by the commonality of the problems facing sustainable management of whales and elephants and of the need for environmental scientists to be aware of the symbolic, ethical and philosophical issues involved in managing natural resources such as marine mammals and African large mammal species, which have so excited the imagination of publics and politicians in distant places. ..
CRIMINAL LAW-EVIDENCE-SILENCE TO ACCUSATION WHILE UNDER ARREST AS ADMISSION OF GUILT
Defendant was convicted of murder. Before the victim died, defendant, handcuffed and in custody of police, had been taken to the hospital room where the victim lay. Eight witnesses were present at the time, and each testified that the victim pointed out the defendant as her assailant. At the trial the witnesses were permitted to testify that when accused of the crime, defendant stood by silently, saying and doing nothing, although it also appeared that he had been told by the police chief to \u27\u27keep your mouth shut. The prosecution capitalized upon defendant\u27s silence as an admission of guilt. On appeal, held, reversed. Defendant, while under arrest, had no duty to speak or to deny the accusation, and his silence could not be construed as an admission. People v. Mleczko, 298 N.Y. 153, 81 N.E. (2d) 65 (1948)
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