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Pressure of air on coming to rest from various speeds

Description: The text gives theoretical formulas from which is computed a table for the pressure of air on coming to rest from various speeds, such as those of aircraft and propeller blades. Pressure graphs are given for speeds from 1 cm. Sec. up to those of swift projectiles.
Date: January 1, 1927
Creator: Zahm, A F
Partner: UNT Libraries Government Documents Department

Analytical and experimental investigation of 90 degrees supersonic turning passages suitable for supersonic compressors or turbines

Description: From Summary: "Four 90 degree two-dimensional turning passages designed by the method of characteristics were tested at an inlet Mach number of 1.71. The measured losses varied from 5 to 15 percent of the inlet stagnation pressure. The smallest loss was obtained for a passage in which separation on the convex surface was minimized through the introduction of a favorable pressure gradient."
Date: September 12, 1949
Creator: Liccini, Luke L.
Partner: UNT Libraries Government Documents Department

Orientation of orifices on bodies of revolution for determination of stream static pressure at supersonic speeds

Description: Report presenting experimental data obtained in the 4- by 4-foot supersonic tunnel for a parabolic body of revolution of large fineness ratio at mach number 1.59, which are analyzed in order to locate positions at which static-pressure orifices will indicate a constant static pressure independent of the pitch-yaw attitude of the body.
Date: January 1952
Creator: Cooper, Morton & Hamilton, Clyde V.
Partner: UNT Libraries Government Documents Department

The Changeable Interaction between Soils and Pressure Cells: Tests and Reviews at the Waterways Experiment Station

Description: Partial abstract: "The principal subjects of the report are the often neglected changes in the interaction of soil and pressure cells with consequent changes in relative errors in cell registrations. The report contains (a) a brief account of the development and use of soil pressure cells; (b) a review of proposed theories for soil-cell interaction; (c) a delayed account of tests with Waterways Experiment Station pressure cells placed in a large triaxial device; and (d) tentative conclusions plus suggestions for calibration, installation, and measuring procedures."
Date: June 1976
Creator: Hvorslev, Mikael Juul
Partner: UNT Libraries Government Documents Department

Measurement of static pressure on aircraft

Description: From Summary: "Existing data on the errors involved in the measurement of static pressure by means of static-pressure tubes and fuselage vents are presented. The errors associated with the various design features of static-pressure tubes are discussed for the condition of zero angle of attack and for the case where the tube is included to the flow. Errors due to variations in the configuration of static-pressure vents are also presented."
Date: April 1, 1957
Creator: Gracey, William
Partner: UNT Libraries Government Documents Department

Cuff-less Blood Pressure Measurement Using a Smart Phone

Description: Blood pressure is vital sign information that physicians often need as preliminary data for immediate intervention during emergency situations or for regular monitoring of people with cardiovascular diseases. Despite the availability of portable blood pressure meters in the market, they are not regularly carried by people, creating a need for an ultra-portable measurement platform or device that can be easily carried and used at all times. One such device is the smartphone which, according to comScore survey is used by 26.2% of the US adult population. the mass production of these phones with built-in sensors and high computation power has created numerous possibilities for application development in different domains including biomedical. Motivated by this capability and their extensive usage, this thesis focuses on developing a blood pressure measurement platform on smartphones. Specifically, I developed a blood pressure measurement system on a smart phone using the built-in camera and a customized external microphone. the system consists of first obtaining heart beats using the microphone and finger pulse with the camera, and finally calculating the blood pressure using the recorded data. I developed techniques for finding the best location for obtaining the data, making the system usable by all categories of people. the proposed system resulted in accuracies between 90-100%, when compared to traditional blood pressure meters. the second part of this thesis presents a new system for remote heart beat monitoring using the smart phone. with the proposed system, heart beats can be transferred live by patients and monitored by physicians remotely for diagnosis. the proposed blood pressure measurement and remote monitoring systems will be able to facilitate information acquisition and decision making by the 9-1-1 operators.
Date: May 2012
Creator: Jonnada, Srikanth
Partner: UNT Libraries

The Vapor Pressure of Arsenic Trioxide

Description: Technical paper issued by the Bureau of Mines over investigations of vapor pressure. The methods and equipment used for the investigations are presented. The results are discussed. This paper includes tables, illustrations, and photographs.
Date: March 1915
Creator: Welch, H. V. & Duschak, L. H.
Partner: UNT Libraries Government Documents Department

Pressure lag in tubing used in flight research

Description: From Introduction: "Tests described in this report were undertaken to obtain a quantitative measure of the pressure lag in typical pressure-tubing systems used by the Ames Aeronautical Laboratory in flight research investigations. Lag measurements were made with both single-direction and oscillating pressure changes. Single-direction pressure changes were investigated to determine if the lag in orifice-pressure lines and in the research airspeed and altitude measuring systems of pursuit-type airplane undergoing flight tests was sufficient to cause an appreciable error in the record of a sudden pressure change. Oscillating pressure changes were investigated with particular reference to the accuracy of pressure peaks in pressure-distribution measurements during the time of buffeting conditions as found in stalls."
Date: July 1945
Creator: Turner, Howard L. & Rathert, George A., Jr.
Partner: UNT Libraries Government Documents Department

Pressure measurements on a sharply converging fuselage afterbody with jet on and off at Mach numbers from 0.8 to 1.6

Description: Report presenting testing of a rocket-powered model of a fin-stabilized parabolic body of revolution with fineness ratio 8.91 and maximum diameter at 80 percent of body station at a range of Mach numbers to determine the static pressures at two orifices on the rearward side of the stabilizing fins. Results regarding measured pressures, comparison of theory and experiment, and drag are provided.
Date: August 10, 1950
Creator: Stoney, William E., Jr. & Katz, Ellis
Partner: UNT Libraries Government Documents Department

Wing-flow study of pressure-drag reduction at transonic speed by projecting a jet of air from the nose of a prolate spheroid of fineness ratio 6

Description: Report presenting a study of the pressure-drag reduction obtained by projecting a high-energy jet of air from the nose of a prolate spheroid at transonic speeds. Results regarding the pressure distribution on the body, pressure drag, shadowgraphs, and some notes regarding the slope of the body and level of shear at the jet exit are provided.
Date: October 26, 1951
Creator: Lopatoff, Mitchell
Partner: UNT Libraries Government Documents Department

Transonic wind-tunnel investigation of static-pressure fluctuations in duct of a scale inlet model of a supersonic fighter-bomber airplane

Description: Report presenting a transonic investigation of the static-pressure fluctuations in the left duct of a scale inlet model of a supersonic fighter-bomber airplane. The amplitude and frequency of pressure fluctuations were measured using an electrical pressure gage mounted on the diffuser wall at several Mach numbers and mass-flow ratios. Results regarding amplitude characteristics of pressure fluctuations, power-spectral analyses, and flow distortions at compressor face are provided.
Date: August 6, 1957
Creator: Brooks, Joseph D.
Partner: UNT Libraries Government Documents Department

Wind-tunnel investigation at Mach 1.9 of multijet-missile base pressures

Description: From Summary: "An experimental wind-tunnel investigation was conducted at Mach 1.9 to determine the pressures acting on the base of a multijet missile using unheated air and carbon dioxide as jet fluids. The variation of base pressure with jet static-pressure ratio was compared with results estimated for an axisymmetric single-jet model and some correlation was observed."
Date: March 3, 1955
Creator: Baughman, L. Eugene
Partner: UNT Libraries Government Documents Department

High Temperature Work in Igneous Fusion and Ebullition, Chiefly in Relation to Pressure

Description: Preface: In the following bulletin I have brought together the more important results of experiments in high temperatures, made since the publication of my bulletin on the thermoelectric measurement of high temperatures.' Chapter I, in addition to pointing out certain inherent relations between metallic vapor tensions, has a direct bearing on pyrometry. Chapters 11 and ii are of geological importance, and the work was done for Mr. Clarence King. Chapter ii shows that in case of the igneous fusion of basic magma, the passage from liquid to solid is one of contraction, and measures the difference of specific volumes at the solidifying temperature. Chapter iii contains a full account of the thermal capacity of the same rock under the same conditions, and by aid of Chapter it leads to a numerical value for the relation of melting point to pressure, for silicates.
Date: 1893
Creator: Barus, Carl
Partner: UNT Libraries Government Documents Department

Effect of the Acceleration of Elongated Bodies of Revolution Upon the Resistance in a Compressible Flow

Description: The problem of the motion of an elongated body of revolution in an incompressible fluid may, as is known, be solved approximately with the aid of the distribution of sources along the axis of the body. In determining the velocity field, the question of whether the body moves uniformly or with an acceleration is no factor in the problem. The presence of acceleration must be taken into account in determining the pressures acting on the body. The resistance of the body arising from the accelerated motion may be computed either directly on the basis of these pressures or with the aid of the so-called associated masses (inertia coefficients). A different condition holds in the case of the motion of bodies in a compressible gas. In this case the finite velocity of sound must be taken into account.
Date: May 1949
Creator: Frankl, F. I.
Partner: UNT Libraries Government Documents Department

Experimental Pressure Distribution on Fuselage Nose and Pilot Canopy of Supersonic Airplane at Mach Number 1.90

Description: An investigation of the pressure distribution on the fuselage nose and the pilot canopy of a supersonic airplane model has been conducted at a Mach number of 1.90 over a wide range of angles of attack and yaw. Boundary layer separation apparently occurred from the upper surface at angles of attack above 24 degrees and from the lower surface at minus 15 degrees. No separation from the sides of the fuselage was evident at yaw angles up to 12 degrees.
Date: October 15, 1948
Creator: Wyatt, DeMarquis D.
Partner: UNT Libraries Government Documents Department

Exploratory investigation of a helicopter pressure-jet system on the Langley helicopter test tower

Description: Report presenting an investigation of a helicopter pressure-jet system. The effects of tip speed, fuel-air ratio, and pressure ratio on the propulsive characteristics of the pressure-jet system have been determined for a range of tip seeds, blade-root stagnation-pressure ratios, and fuel-air ratios. Results regarding tip-burner specific propulsive horsepower, propulsive horsepower per unit mean duct area, tip-burner specific fuel consumption, ratio of propulsive horsepower to equivalent air horsepower, effect of whirling on tip-unit thrust, effect of whirling on the tip-burner inlet pressure, effect of auxiliary fuel flow, power-off drag of tip units, and overall specific fuel consumption of pressure-jet system are provided.
Date: July 27, 1956
Creator: Makofski, Robert A. & Shivers, James P.
Partner: UNT Libraries Government Documents Department

Altitude Starting Tests of a 1000-Pound-Thrust Solid-Propellant Rocket

Description: Four solid-propellant rocket engines of nominal 1000-pound-thrust were tested for starting characteristics at pressure altitudes ranging from 112,500 to 123,000 feet and at a temperature of -75 F. All engines ignited and operated successfully. Average chamber pressures ranged from 1060 to ll90 pounds per square inch absolute with action times from 1.51 to 1.64 seconds and ignition delays from 0.070 t o approximately 0.088 second. The chamber pressures and action times were near the specifications, but the ignition delay was almost twice the specified value of 0.040 second.
Date: August 27, 1952
Creator: Sloop, John L.; Rollbuhler, R. James & Krawczonek, Eugene M.
Partner: UNT Libraries Government Documents Department

Investigation of a two-step nozzle in an 11-inch hypersonic tunnel

Description: Report discussing flow surveys made of several nozzles using two 2-dimensional steps at Mach number 6.98. Results regarding wall-pressure surveys, disturbance patterns in expansion, total-pressure survey, temperature recovery, and general nozzle characteristics are provided.
Date: October 25, 1949
Creator: McLellan, Charles H.; Williams, Thomas W. & Bertram, Mitchel H.
Partner: UNT Libraries Government Documents Department

Investigation of separated flows in supersonic and subsonic streams with emphasis on the effect of transition

Description: Report presents the results of experimental and theoretical research conducted on flow separation associated with steps, bases, compression corners, curved surfaces, shock-wave boundary-layer reflections, and configurations producing leading-edge separation. Results were obtained from pressure-distribution measurements, shadowgraph observations, high-speed motion pictures, and oil-film studies. The maximum scope of measurement encompassed Mach numbers between 0.4 and 3.6, and length Reynolds numbers between 4,000 and 5,000,000.
Date: November 29, 1956
Creator: Chapman, Dean R.; Kuehn, Donald M. & Larson, Howard K.
Partner: UNT Libraries Government Documents Department

Investigation of Pressure Distribution over an Extended Leading-Edge Flap on a 42 Degrees Sweptback Wing

Description: Pressure distribution over an extended leading-edge flap on a 42 degree swept-back wing was investigated. Results indicate that the flap normal-force coefficient increased almost linearly with the angle of attack to a maximum value of 3.25. The maximum section normal-force coefficient was located about 30 percent of the flap span outboard of the inboard end and had a value of 3.75. Peak negative pressures built up at the flap leading edge as the angle of attack was increased and caused the chordwise location of the flap center of pressure to be move forward.
Date: December 19, 1947
Creator: Conner, D. William & Foster, Gerald V.
Partner: UNT Libraries Government Documents Department

Performance of a blunt-lip side inlet with ramp bleed, bypass, and a long constant-area duct ahead of the engine : Mach number 0.66 and 1.5 to 2.1

Description: Unsteady shock-induced separation of the ramp boundary layer was reduced and stabilized more effectively by external perforations than by external or internal slots. At Mach 2.0 peak total-pressure recovery was increased from 0.802 to 0.89 and stable mass-flow range was increased 185 percent over that for the solid ramp. Peak pressure recovery occurred just before instability. The 7 and one-third-diameter duct ahead of the engine reduced large total-pressure distortions but was not as successful for small distortions as obtained with throat bleed. By removing boundary-layer air the bypass nearly recovered the total-pressure loss due to the long duct.
Date: December 28, 1956
Creator: Allen, John L.
Partner: UNT Libraries Government Documents Department