7,793 research outputs found
Causes of the 1980s Slump in Europe
macroeconomics, slump, unemployment, Europe, EEC, macroeconomic theory
Effects of planform geometry on hover performance of a 2-meter-diameter model of a four-bladed rotor
Hover tests were conducted on three small scale rotors to evaluate the effects of blade planform taper on rotor hover performance. Tests were conducted on a rectangular swept-tip configuration, on a configuration with a 3 to 1 taper over the outboard 20 percent of the span, and on a configuration with a 5 to 1 taper over the outboard 20 percent of the blade span. The investigation covered a range of thrust coefficients from 0 to 0.0075 and a range of tip speeds from 300 to 600 ft/sec. The tests showed that both tapered configurations had better hover performance than the swept-tip rectangular configuration and that the 3 to 1 taper configuration was better than the 5 to 1 taper configuration. The test results were compared with predictions made with a prescribed wake analysis, a momentum analysis, and a simplified free wake analysis
Description of the US Army small-scale 2-meter rotor test system
A small-scale powered rotor model was designed for use as a research tool in the exploratory testing of rotors and helicopter models. The model, which consists of a 29 hp rotor drive system, a four-blade fully articulated rotor, and a fuselage, was designed to be simple to operate and maintain in wind tunnels of moderate size and complexity. Two six-component strain-gauge balances are used to provide independent measurement of the rotor and fuselage aerodynamic loads. Commercially available standardized hardware and equipment were used to the maximum extent possible, and specialized parts were designed so that they could be fabricated by normal methods without using highly specialized tooling. The model was used in a hover test of three rotors having different planforms and in a forward flight investigation of a 21-percent-scale model of a U.S. Army scout helicopter equipped with a mast-mounted sight
Love\u27s Mystery : Waltzes
https://digitalcommons.library.umaine.edu/mmb-ps/2097/thumbnail.jp
A Study of the Perception of Verbal Aggression in Black and White Females
The purpose of this study was to compare black and white females\u27 perceptions of verbal aggression. Eighty black and 80 white female participants read a short dialogue of two female college roommates engaged in a verbal interaction. One of these women was arbitrarily selected as the identified aggressor; the other, the target. Pilot studies had established that participants similar to those used in this study thought that the dialogue contained verbal aggression and that each of the persons was equally verbally aggressive. As the participants read the dialogue, they had access to drawings of the two women. The experimental conditions were manipulated to produce a 2 x 2 x 2 design: race of participant (black or white), race of aggressor (black or white), and race of target (black or white). The dependent measures of aggressiveness were three scales of the Interpersonal Behavior Survey (1980) and a combination of two scales from the Adjective Check List (1952). There was a main effect for race of participant, such that ratings of aggression made by white females were significantly higher than those made by black females. There were no main effects for either race of aggressor or race of target; and there were no interactions. Implications related to the socialization process of black and white females and suggestions for future research are discussed
Upper-surface-blowing flow-turning performance
Jet exhaust flow-turning characteristics were determined for systematic variations in upper-surface blowing exhaust nozzles and trailing-edge flap configuration variables from experimental wind-off (static) flow studies. For conditions with parallel flow exhausting from the nozzle, jet height (as indicated by nozzle exit height) and flap radius were found to be the most important parameters relating to flow turning. Nonparallel flow from the nozzle, as obtained from an internal roof angle and/or side spread angle, had a large favorable effect on flow turning. Comparisons made between static turning results and wind tunnel aerodynamic studies of identical configurations indicated that static flow-turning results can be indicative of wind-on powered lift performance for both good and poor nozzle-flap combinations but, for marginal designs, can lead to overly optimistic assessment of powered lift potential
Growth-Quality Evaluation of Black Walnut Wood. Part III-An Anatomical Study of Color Characteristics of Black Walnut Veneer
Because wood color is an important quality characteristic in black walnut (Juglans nigra L.), a study was devised to examine some cellular features of heartwood coloration using microspectrophotometric techniques. Five commercially prepared veneer samples exhibiting low macro-luminance (darker) and five exhibiting high macro-luminance (lighter) were chosen for microscopic color analysis. Statistically significant differences were found between the high and low macro-luminance sample groups in the micro-luminance color value in some cellular features (axial parenchyma walls, ray parenchyma walls, fiber walls, and ray parenchyma inclusions). Also observed were large differences in the dominant wavelength of ray parenchyma inclusions between the sample groups. These results suggest that quality of these coloration pigments (phenolics) is more important than quantity for overall color variations
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