Static force tests of a sharp leading edge delta-wing model at ambient and cryogenic temperatures with a description of the apparatus employed

A sharp leading edge delta-wing model was tested through an angle-of-attack range at Mach numbers of 0.75, 0.80, and 0.85 at both ambient and cryogenic temperatures in the Langley 1/3-meter transonic cryogenic tunnel. Total pressure was varied with total temperature in order to hold test Reynolds number constant at a given Mach number. Agreement between the aerodynamic data obtained at ambient and cryogenic temperatures indicates that flows with leading-edge vortex effects are duplicated properly at cryogenic temperatures. The test results demonstrate that accurate aerodynamic data can be obtained by using conventional force-testing techniques if suitable measures are taken to minimize temperature gradients across the balance and to keep the balance at ambient (warm) temperatures during cryogenic operation of the tunnel

Exploratory study of public school administrators' perceptions regarding public school education advanced by homeschool parents

Scope and Method of Study: Qualitative Research using 15 Public School Administrators representing three public school systems in Oklahoma County. The administrators will divide into 3 Focus Group sessions and discuss 13 open-ended discussion questions about the allegations made against public schools by homeschool parents.Findings and Conclusions: Public School Administrators must talk more about the positive things that are happening in public schools-things that seldom are mentioned by the media. It is all but impossible to raise children in a world completely surrounded by only homeschoolers and homeschool enthusiasts. The public is all around us and cannot be completely avoided

Guerrilla Radio: Has the Time Come for a Full Performance Right in Sound Recordings?

Musicians and songwriters occupy a unique place in society as purveyors of composition and expression that impart an intangible benefit to society. Understanding the value of Science and useful Arts, the Founders provided Constitutional protection for individuals spending time, money, and energy pursuing creative endeavors. Music defines generations and pivotal moments in history, and has rightfully taken its place at the forefront of human expression. When music began reaching the masses in the early twentieth century, both record labels and radio, even in its infancy, helped propel artists to the national spotlight. Johnny Cash, Ray Charles, and Pearl Jam all owe their success to the efforts and collaborations of radio and label executives--and of course their own talents. The relationship between artists, labels, and radio has not always been symbiotic, especially on the issue of compensation, and the advent of the Internet has helped matters little. The fight over profit allocation between these key players in the music industry is once again on display. The re-introduction in Congress of the Performance Rights Act raises issues about the appropriate extent of protection for a performance right to copyright owners of sound recordings. Artists and labels want radio to compensate them for their talents and time; radio says traditional broadcasting does not threaten record sales and serves as free advertising. Though numerous pushes against broadcasters for this performance right have failed, it is a recurring issue unlikely to disappear in the future. This Note examines the history of copyright protection for sound recordings and other musical works in the United States. It begins by examining the statutory development of copyright protection for musical compositions and sound recordings, and the nature of those compensation schemes. The Note then introduces the Performance Rights Act, and analyzes the potential reasons for and effects of the Acton radio, record labels, and artists, as well as the changing scope of copyright protection in both traditional, terrestrial radio and digital transmissions. Finally, this Note suggests Congress should pass the Performance Rights Act, but should consider ways to minimize negative financial implications for radio, and align the bill with the goals of American copyright law

Application of Computer Axial Tomography (CAT) to measuring crop canopy geometry

The feasibility of using the principles of computer axial topography (CAT) to quantify the structure of crop canopies was investigated because six variables are needed to describe the position-orientation with time of a small piece of canopy foliage. Several cross sections were cut through the foliage of healthy, green corn and soybean canopies in the dent and full pod development stages, respectively. A photograph of each cross section representing the intersection of a plane with the foliage was enlarged and the air-foliage boundaries delineated by the plane were digitized. A computer program was written and used to reconstruct the cross section of the canopy. The approach used in applying optical computer axial tomography to measuring crop canopy geometry shows promise of being able to provide needed geometric information for input data to canopy reflectance models. The difficulty of using the CAT scanner to measure large canopies of crops like corn is discussed and a solution is proposed involving the measurement of plants one at a time

Simulation of flight test conditions in the Langley pilot transonic cryogenic tunnel

The theory and advantages of the cryogenic tunnel concept are briefly reviewed. The unique ability to vary temperature independently of pressure and Mach number allows, in addition to large reductions in model loads and tunnel power, the independent determination of Reynolds number, Mach number, and aeroelastic effects on the aerodynamic characteristics of the model. Various combinations of Reynolds number and dynamic pressure are established to represent accurately flight variations of aeroelastic deformation with altitude changes. The consequences of the thermal and caloric imperfections of the test gas under cryogenic conditions were examined and found to be insignificant for operating pressures up to 5 atm. The characteristics of the Langley pilot transonic cryogenic tunnel are described and the results of initial tunnel operation are presented. Tests of a two-dimensional airfoil at a Mach number of 0.85 show identical pressure distributions for a chord Reynolds number of 8,600,000 obtained first at a stagnation pressure of 4.91 atm at a stagnation temperature of 322.0 K and then at a stagnation pressure of 1.19 atm at a stagnation temperature of 116.5 K

Exploring the factors that influence attitudes and achievement when students take computerized tests

Currently, a problem exists in K-12 education related to the use of technology for the assessment of student learning. Specifically, due to the lack of access to and infrequent use of computers for middle school students, the rise in the use of high stakes computer-based tests may negatively impact student test scores in poor, urban schools. The conceptual framework of this study was informed by Albert Bandura\u27s theory of self-efficacy, the work of The National Center for Fair and Open Testing regarding ending the misuses and flaws of standardized testing, and James Popham\u27s research on quality assessment. The central research question explored the influence of socioeconomic status, computer access/use, attitudes towards computers, and student achievement levels on computerized tests. This research study was a case study involving 2 charter schools in Michigan. The researcher assumed the role of a non-participant observer and was the primary source for data collection and analysis. The participants for this study were students in Grades 6, 7, and 8 at one suburban and one urban charter school. Multiple sources of evidence were collected, including observations, surveys, and documents. Data analysis was conducted at two levels: category construction was used to examine data for each single case, and a cross-case analysis was used to examine the data for patterns and themes, using the research questions as a guide. A key finding was that home computer access coupled with sole use had a positive influence on student achievement, a positive influence on self-perceptions of computer ability, and significantly influenced the amount of computer usage. Implications for positive social change in education were that practitioners would become aware of the negative effects of computerized testing and implement strategies to mitigate the negative effects

Analysis of validation tests of the Langley pilot transonic cryogenic tunnel

A pilot transonic cryogenic pressure tunnel has recently been developed and proof tested at the NASA Langley Research Center. In addition to providing an attractive method for obtaining high Reynolds number results at moderate aerodynamic loadings and tunnel power, this unique tunnel allows the independent determination of the effects of Reynolds number, Mach number, and dynamic pressure (aeroelasticity) on the aerodynamic characteristics of the model under test. The proof of concept experimental and theoretical studies are briefly reviewed. Experimental results obtained on both two- and three-dimensional models have substantiated that cryogenic test conditions can be set accurately and that cryogenic gaseous nitrogen is a valid test medium

The cryogenic wind tunnel concept for high Reynolds number testing

Theoretical considerations indicate that cooling the wind-tunnel test gas to cryogenic temperatures will provide a large increase in Reynolds number with no increase in dynamic pressure while reducing the tunnel drive-power requirements. Studies were made to determine the expected variations of Reynolds number and other parameters over wide ranges of Mach number, pressure, and temperature, with due regard to avoiding liquefaction. Practical operational procedures were developed in a low-speed cryogenic tunnel. Aerodynamic experiments in the facility demonstrated the theoretically predicted variations in Reynolds number and drive power. The continuous-flow-fan-driven tunnel is shown to be particularly well suited to take full advantage of operating at cryogenic temperatures

Aerodynamic damping and oscillatory stability of a model of a proposed HL-10 vehicle in pitch at Mach numbers from 0.20 to 2.86 and in YAW at Mach numbers from 0.20 to 1.20

Wind tunnel tests of a proposed HL-10 lifting body vehicle were conducted to determine the subsonic and transonic aerodynamic characteristics. The conditions under which the tests were conducted are described. The tests indicate that the configuration has slightly positive damping in pitch except at higher angles of attack at Mach numbers of 0.8, 0.9, and 1.0. At supersonic speeds, the configuration has positive damping in pitch for all test conditions. At subsonic and transonic speed, the configuration has positive damping and positive stability in yaw for all test conditions

Dynamic-stability tests on an aircraft escape module at Mach numbers from 0.40 to 2.16

Wind-tunnel measurements of the aerodynamic damping and oscillatory stability of a model of a proposed escape module for a military aircraft have been made using a small-amplitude forced-oscillation technique in pitch and yaw at Mach numbers from 0.40 to 2.16 and in roll at Mach numbers from 0.40 to 1.20. The results in pitch indicate regions in the angle-of-attack range where the model exhibits large and rapid changes in both damping and stability with angle of attack, probably caused by vortex flow over the fins. There was no pronounced effect of change in angle of attack on damping in yaw. Except for the highest Mach number, negative damping in roll was produced at high negative angles of attack