8,940 research outputs found
An investigation in the correlation between Ayurvedic body-constitution and food-taste preference
Preliminary Report on Free Flight Tests
Results are presented for a series of tests made by the Advisory Committee's staff at Langley Field during the summer of 1919 with the objectives of determining the characteristics of airplanes in flight and the extent to which the actual characteristics differ from those predicted from tests on models in the wind tunnel, and of studying the balance of the machines and the forces which must be applied to the controls in order to maintain longitudinal equilibrium
Accelerometer design
In connection with the development of an accelerometer for measuring the loads on airplanes in free flight a study of the theory of such instruments has been made, and the results of this study are summarized in this report. A portion of the analysis deals particularly with the sources of error and with the limitations placed on the location of the instrument in the airplane. The discussion of the dynamics of the accelerometer includes a study of its theoretical motions and of the way in which they are affected by the natural period of vibration and by the damping, together with a report of some experiments on the effect of forced vibrations on the record
Angles of Attack and Air Speeds During Maneuvers
In seeking further information as to the nature of maneuvers and as to the maneuverability characteristics of airplanes, continuous measurements of the angles of attack and air speeds at several points along the wings have been made during spins and loops. Very striking results have been obtained with reference to the rolling velocity and the distribution of load in spins and the variation of the angle of attack in loops, a surprisingly large range of angle being experienced during slow loops. The flight tests and results are fully described in this report
Design of Wind Tunnels and Wind Tunnel Propellers II
This report is a continuation of National Advisory Committee for Aeronautics report no. 73. The variations in velocity and direction of the wind stream were studied by means of a recording air speed meter and a recording yawmeter. The work was carried on both in a 1-foot diameter model tunnel and in a 5-foot full-size tunnel, and wherever possible comparison was made between them. It was found that placing radial vanes directly before the propeller in the exit cone increased the efficiency of the tunnel to a considerable extent and also gave a steadier flow
Wind Tunnel Balances
Report embodies a description of the balance designed and constructed for the use of the National Advisory Committee for Aeronautics at Langley Field, and also deals with the theory of sensitivity of balances and with the errors to which wind tunnel balances of various types are subject
United States benefits of improved worldwide wheat crop information from a LANDSAT system
The value of worldwide information improvements on wheat crops, promised by LANDSAT, is measured in the context of world wheat markets. These benefits are based on current LANDSAT technical goals and assume that information is made available to all (United States and other countries) at the same time. A detailed empirical sample demonstration of the effect of improved information is given; the history of wheat commodity prices for 1971-72 is reconstructed and the price changes from improved vs. historical information are compared. The improved crop forecasting from a LANDSAT system assumed include wheat crop estimates of 90 percent accuracy for each major wheat producing region. Accurate, objective worldwide wheat crop information using space systems may have a very stabilizing influence on world commodity markets, in part making possible the establishment of long-term, stable trade relationships
Iron-Line Emission as a Probe of Bardeen-Petterson Accretion Disks
In this work we show that Bardeen-Petterson accretion disks can exhibit
unique, detectable features in relativistically broadened emission line
profiles. Some of the unique characteristics include inverted line profiles
with sharper red horns and softer blue horns and even profiles with more than 2
horns from a single rest-frame line. We demonstrate these points by
constructing a series of synthetic line profiles using simple two-component
disk models. We find that the resultant profiles are very sensitive to the two
key parameters one would like to constrain, namely the Bardeen-Petterson
transition radius r_{BP} and the relative tilt \beta between the two disk
components over a range of likely values [10 < r_{BP}/(GM/c^2) < 40 ; 15deg <
\beta < 45deg]. We use our findings to show that some of the ``extra'' line
features observed in the spectrum of the Seyfert-I galaxy MCG--6-30-15 may be
attributable to a Bardeen-Petterson disk structure. Similarly, we apply our
findings to two likely Bardeen-Petterson candidate Galactic black holes - GRO
J1655-40 and XTE J1550-564. We provide synthetic line profiles of these systems
using observationally constrained sets of parameters. Although we do not
formally fit the data for any of these systems, we confirm that our synthetic
spectra are consistent with current observations.Comment: 13 pages, 11 figures, submitted to Ap
CC Sculptoris: A superhumping intermediate polar
We present high speed optical, spectroscopic and Swift X-ray observations
made during the dwarf nova superoutburst of CC Scl in November 2011. An orbital
period of 1.383 h and superhump period of 1.443 h were measured, but the
principal new finding is that CC Scl is a previously unrecognised intermediate
polar, with a white dwarf spin period of 389.49 s which is seen in both optical
and Swift X-ray light curves only during the outburst. In this it closely
resembles the old nova GK Per, but unlike the latter has one of the shortest
orbital periods among intermediate polars.Comment: Accepted for publication in MNRAS; 11 pages, 19 figure
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