2,973 Matching Results

Search Results

Advanced search parameters have been applied.


Description: "Momentarium" is a collection of poems that examines the instability of moments. By engaging with photography, the poems examine the strengths and flaws in representation. Qualified accuracy, in other words representations that exact no absolute authenticity, are paradoxically, most accurate. The original poems attempt to express both empathy an end to empathy, "I mean to give you what you cannot keep: a blue twice as true" and "I mean to give you what I cannot." The competing forces animate a contingent moment, before it becomes the past.
Access: This item is restricted to UNT Community Members. Login required if off-campus.
Date: August 2017
Creator: Zuehlke, Karl
Partner: UNT Libraries

Calibration of Instruments for Measuring Wind Velocity and Direction

Description: Signal Corps wind equipment AN/GMQ-1 consisting of a 3-cup anemometer and wind vane was calibrated for wind velocities from 1 to 200 miles per hour. Cup-shaft failure prevented calibration at higher wind velocities. The action of the wind vane was checked and found to have very poor directional accuracy below a velocity of 8 miles per hour. After shaft failure was reported to the Signal Corps, the cup rotors were redesigned by strengthening the shafts for better operation at high velocities. The anemometer with the redesigned cup rotors was recalibrated, but cup-shaft failure occurred again at a wind velocity of approximately 220 miles per hour. In the course of this calibration two standard generators were checked for signal output variation, and a wind-speed meter was calibrated for use with each of the redesigned cup rotors. The variation of pressure coefficient with air-flow direction at four orifices on a disk-shaped pitot head was obtained for wind velocities of 37.79 53.6, and 98.9 miles per hour. A pitot-static tube mounted in the nose of a vane was calibrated up to a dynamic pressure of 155 pounds per square foot, or approximately 256 miles per hour,.
Date: January 1, 1950
Creator: Vogler, Raymond D. & Pilny, Miroslav J.
Partner: UNT Libraries Government Documents Department

Development and Construction of an Interferometer for Optical Measurements of Density Fields

Description: A method of interference is described in the present report which promises profitable application in aeronautical research. The physical foundation of the method and a simple method of adjustment are briefly discussed. The special technical construction of the instrument is described which guarantees its use also in the case of vibrations of the surrounding space and permits the investigation of unsteady phenomena. It is found that the interference method will make the small differences in density in the flow field around the body even at low speeds. (40 m/sec) optically measurable.
Date: September 1, 1947
Creator: Zobel, Th.
Partner: UNT Libraries Government Documents Department

A New Apparatus for Measuring the Temperature at Machine Parts Rotating at High Speeds

Description: After a brief survey of the available methods for measuring the temperatures of machine parts at high speed, in particular turbine blades and rotors, an apparatus is described which is constructed on the principle of induction. Transmission of the measuring current by sliding contacts therefore is avoided. Up-to-date experiments show that it is possible to give the apparatus a high degree of sensitivity and accuracy. In comparison with sliding contact types, the present apparatus shows the important advantage that it operates for any length of time without wear, and that the contact difficulties, particularly occurring at high sliding speeds,are avoided.
Date: April 1, 1945
Creator: Gnam, E.
Partner: UNT Libraries Government Documents Department

Calibration Tests of a Japanese Log Rodmeter

Description: A Japanese log rodmeter of the rotating-vane impeller type, with a commutator on the impeller shaft, was calibrated in Langley tank no. 1. The rotational speed of two impellers was determined for forward speeds up to 24 knots at angles of yaw up to ?10 0 . In general, the rotational speeds of two apparently identical impellers tested in the rodmeter decreased with increasing yaw angle, right yaw causing a greater decrease than left yaw. The difference in calibration between the two impellers was approximately the same as that produced by a change in yaw angle from 50 left to 50 right. Evidence of cavitation within the impeller fairing appeared at speeds above 24 knots.
Date: March 14, 1949
Creator: Mottard, Elmo J.
Partner: UNT Libraries Government Documents Department

The NACA high-speed motion-picture camera optical compensation at 40,000 photographs per second

Description: The principle of operation of the NACA high-speed camera is completely explained. This camera, operating at the rate of 40,000 photographs per second, took the photographs presented in numerous NACA reports concerning combustion, preignition, and knock in the spark-ignition engine. Many design details are presented and discussed, details of an entirely conventional nature are omitted. The inherent aberrations of the camera are discussed and partly evaluated. The focal-plane-shutter effect of the camera is explained. Photographs of the camera are presented. Some high-speed motion pictures of familiar objects -- photoflash bulb, firecrackers, camera shutter -- are reproduced as an illustration of the quality of the photographs taken by the camera.
Date: January 1, 1946
Creator: Miller, Cearcy D
Partner: UNT Libraries Government Documents Department

Realismo Magico Digital: An Exploration of Self-Identity

Description: The internal necessity to rediscover myself constantly drives me back to the country where I spent most of my life, Mexico. I was born and raised in the heart of the world's largest metropolis, Mexico City and through the years I have photographed in locations with important significance for Mexican culture as well as for my personal history. I reorganize and reinvent these places, and by staging models there, I construct my personal interpretation of the Mexican way of life involving the world of “manana” (tomorrow) with its “dictadura perfecta” (perfect dictatorship), where opposite and contradictory situations exist side by side. I am particularly interested in the relationship between people and their environ-ment and I use this theme as a means to explore my own identity as a Mexican. One strategy involves juxtaposing cultural signifiers of Mexican culture. My images are an examination and a projection of my ideals, fears, and dreams about my country and myself.
Date: May 2001
Creator: Mateos, Cesar Augusto
Partner: UNT Libraries

The Calculated and Measured Performance Characteristics of a Heated-Wire Liquid-Water-Content Meter for Measuring Icing Severity

Description: Ground tests have been made of an instrument which, when assembled in a more compact form for flight installation, could be used to obtain statistical flight data on the liquid-water content of icing clouds and to provide an indication of icing severity. The sensing element of the instrument consists of an electrically heated wire which is mounted in the air stream. The degree of cooling of the wire resulting from evaporation of the impinging water droplets is a measure. of the liquid-water content of the cloud. Determination of the value of the liquid-water content from the wire temperature at any instant requires a knowledge of the airspeed, altitude, and air temperature. An analysis was made of the temperature response of a heated wire exposed to an air stream containing water drops. Comparisons were made of the liquid-water content as measured with several heated wires and absorbent cylinders in an artificially produced cloud. For one of the wires, comparative tests were made with a rotating-disk icing-rate meter in an icing wind tunnel. From the test results, it was shown that an instrument for measuring the concentration of liquid water in an air stream can be built using an electrically heated wire of known temperatureresistance characteristics, and that the performance of such a device can be predicted using appropriate theory. Although an instrument in a form suitable for gathering statistical data in flight was not built, the practicability of constructing such an instrument was illustrated. The ground-test results indicated that a flight heated-wire instrument would be simple and durable, would respond rapidly to variations in liquid-water content, and could be used for the measurement of water content in clouds which are above freezing temperature, as well as in icing clouds.
Date: January 1, 1952
Creator: Neel, Carr B. & Steinmetz, Charles P.
Partner: UNT Libraries Government Documents Department

Flight Instrument for Measurement of Liquid-Water Content in Clouds at Temperatures Above and Below Freezing

Description: A principle formerly used in an instrument for cloud detection was further investigated to provide a simple and rapid means for measuring the liquid-water content of clouds at temperatures above and below freezing. The instrument consists of a small cylindrical element so operated at high surface temperatures that the impingement of cloud droplets creates a significant drop in the surface temperature. ? The instrument is sensitive to a wide range of liquid-water content and was calibrated at one set of fixed conditions against rotating multicylinder measurements. The limited conditions of the calibration Included an air temperature of 20 F, an air velocity of 175 miles per hour, and a surface temperature in clear air of 475 F. The results obtained from experiments conducted with the instrument indicate that the principle can be used for measurements in clouds at temperatures above and below freezing. Calibrations for ranges of airspeed, air temperature, and air density will be necessary to adapt the Instrument for general flight use.
Date: March 5, 1951
Creator: Perkins, Porter J.
Partner: UNT Libraries Government Documents Department

An Instrument Employing a Coronal Discharge for the Determination of Droplet-Size Distribution in Clouds

Description: A flight instrument that uses electric means for measuring the droplet-size distribution in above-freezing clouds has been devised and given preliminary evaluation in flight. An electric charge is placed on the droplets and they are separated aerodynamically according to their mass. Because the charge placed on the droplets is a. function of the droplet size, the size spectrum can 'be determined by measurement of the charge deposited on cylinders of several different sizes placed to intercept the charged droplets. An expression for the rate of charge acquisition by a water droplet in a field of coronal discharge is derived. The results obtained in flight with an instrument based on the method described indicate that continuous records of droplet-size spectrum variations in clouds can be obtained. The experimental instrument was used to evaluate the method and was not refined to the extent necessary for obtaining conclusive meteorological data. The desirable features of an instrument based on the method described are (i) The instrument can be used in clouds with temperatures above freezing; (2) the size and the shape of the cylinders do not change during the exposure time; (3) the readings are instantaneous and continuous; (4) the available sensitivity permits the study of variations in cloud structures of less than 200 feet in extent.
Date: September 1951
Creator: Brun, Rinaldo J.; Levine, Joseph & Kleinknecht, Kenneth S.
Partner: UNT Libraries Government Documents Department

Adaptation of a Cascade Impactor to Flight Measurement of Droplet Size in Clouds

Description: A cascade impactor, an instrument for obtaining: the size distribution of droplets borne in a low-velocity air stream, was adapted for flight cloud droplet-size studies. The air containing the droplets was slowed down from flight speed by a diffuser to the inlet-air velocity of the impactor. The droplets that enter the impactor impinge on four slides coated with magnesium oxide. Each slide catches a different size range. The relation between the size of droplet impressions and the droplet size was evaluated so that the droplet-size distributions may be found from these slides. The magnesium oxide coating provides a permanent record. of the droplet impression that is not affected by droplet evaporation after the. droplets have impinged.
Date: September 18, 1951
Creator: Levine, Joseph & Kleinknecht, Kenneth S.
Partner: UNT Libraries Government Documents Department

Comparison of Three Multicylinder Icing Meters and Critique of Multicylinder Method

Description: Three multicylinder cloud meters, fundamentally similar but differing in important details, were compared in use at the Mount Washington Observatory. Determinations of liquid water content were found to agree within the limits of the probable error, but the two instruments designed by the National Advisory Committee for Aeronautics indicated larger drop sizes than did the Observatory's instrument, apparently because of spurious ice catch on the rather rough surface of the larger cylinders. Comparisons of drop-size distribution were largely indeterminate., In a critique of the method, the probable error of determination of liquid water content was found to be +/-8 percent; of drop size, +/-6 percent; and of drop-size distribution, about +/-0.7 unit of the modulus of distribution. Of the systematic errors, run-off of unfrozen water is most important, blow-off and erosion seldom being hampering. Revision of collection-efficiency computations for cylinders in clouds with distributed drop sizes was found necessary and also revision of one of the correction-factor graphs heretofore used. The assumption of constant ice density in deriving cylinder size was found to be permissible for cylinders 1 inch or more in diameter.
Date: June 1, 1952
Creator: Howell, Wallace E.
Partner: UNT Libraries Government Documents Department

An Oil-Stream Photomicrographic Aeroscope for Obtaining Cloud Liquid-Water Content and Droplet Size Distributions in Flight

Description: An airborne cloud aeroscope by which droplet size, size distribution, and liquid-water content of clouds can be determined has been developed and tested in flight and in wind tunnels with water sprays. In this aeroscope the cloud droplets are continuously captured in a stream of oil, which Is then photographed by a photomicrographic camera. The droplet size and size distribution can be determined directly from the photographs. With the droplet size distribution known, the liquid-water content of the cloud can be computed from the geometry of the aeroscope, the airspeed, and the oil-flow rate. The aeroscope has the following features: Data are obtained semi-automatically, and permanent data are taken in the form of photographs. A single picture usually contains a sufficient number of droplets to establish the droplet size distribution. Cloud droplets are continuously captured in the stream of oil, but pictures are taken at Intervals. The aeroscope can be operated in icing and non-icing conditions. Because of mixing of oil in the instrument, the droplet-distribution patterns and liquid-water content values from a single picture are exponentially weighted average values over a path length of about 3/4 mile at 150 miles per hour. The liquid-water contents, volume-median diameters, and distribution patterns obtained on test flights and in the Lewis icing tunnel are similar to previously published data.
Date: January 1, 1956
Creator: Hacker, Paul T.
Partner: UNT Libraries Government Documents Department

Counterfactual Image of Don and Marge 1946

Description: This photograph depicts a couple standing on the sidewalk next to a street. There are buildings in the background and snow along the ground. The couple appears in black and white and the surroundings appear in color. The photographer placed the black and white photograph of the couple taken in 1946 and put it on top of a photograph of the same location taken over 50 years later.
Date: unknown
Creator: O'Connor, Brian Clark
Partner: UNT College of Information