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Manometer for Recording Air Speed

Description: If it is desired to record the pressure difference given a gauge, the manometer must answer the following conditions: 1) It must respond quickly so that all speed variations will be correctly recorded; 2) It must not be affected by rectilinear or curvelinear accelerations. Hence, movable parts must be counterbalanced. An instrument which met these criteria is discussed as well as details of construction.
Date: February 1922
Creator: Wieselsberger, C.
Partner: UNT Libraries Government Documents Department

A Miniature Electrical Pressure Gage Utilizing a Stretched Flat Diagram

Description: "A variable-air-gap, inductance-type, electrical pressure gage is described that is basically 7/16 inch in diameter and 1/4 inch in thickness. The gage was designed to measure accurately pressures fluctuating at high frequencies and has proved to be a value as a general-purpose electrical gage for aeronautical work where small size and minimum response to acceleration forces are important factors. Design equations and curves are presented which can be used to predict the deflections and fundamental natural frequencies of stretched flat diaphragms" (p. 1).
Date: April 1952
Creator: Patterson, John L.
Partner: UNT Libraries Government Documents Department

Response of a recessed pressure transducer with a millisecond pressure step input

Description: All too often, dynamic pressure measurements are made with the sensitive part of the transducer, the diaphragm, recessed and away from the pressure source. If the transducer has been recessed far enough from the pressure source, an invalid pressure measurement will result. To explore the effect of recessing, the Reynolds pneumatic accelerator was used to produce a pressure step with a rise time from 0.5 to 2 ms. Results are presented. (auth)
Date: November 30, 1973
Creator: Shay, W. M. & Kuhlman, J.
Partner: UNT Libraries Government Documents Department

Bureau of Mines Multiple-Diaphragm Recording Subsurface-Pressure Gage

Description: Report issued by the U.S. Bureau of Mines on the measuring of temperature and pressure in oil and gas wells. Descriptions of the instrumentation developed and used for these measurements are presented. This report includes tables, graphs, and illustrations.
Date: November 1935
Creator: Berwald, W. B.; Buss, H. A. & Reistle, C. E., Jr.
Partner: UNT Libraries Government Documents Department

Response of Pressure Gauges to Dust-Laden Shock Waves

Description: "A series of shock tube studies demonstrate that two types of pressure gauges respond to dust carried with shock waves by indicating an increase in dynamic pressure. This contribution to the dynamic pressure is approximately the product of the dust density and the square of the dust velocity under the experimental conditions. Besides this information studies give insight into the interaction of a square shock wave with dust when that dust is placed in a plane before and parallel to the shock front. It is found that the shape of the pressure wave is little changed except for a rounding of the front. The dust, after accelerating, is carried as a pulse with the mass flow velocity of the air."
Date: 1954-05-21?
Creator: Banister, John Robert & Broyles, C. D.
Partner: UNT Libraries Government Documents Department

Reduction of Data for Piston Gage Pressure Measurements

Description: Report issued by the U.S. National Bureau of Standards discussing piston gage pressure and reducing errors of measurement. Sources of error are described and evaluated in order to "reduce the magnitude of overall error of measurement" (p. 1). This report includes tables, and illustrations.
Date: June 17, 1963
Creator: Cross, J. L.
Partner: UNT Libraries Government Documents Department

A New Analytical Solution for Diaphragm Deflection and its Application to a Surface-Micromachined Pressure Sensor

Description: An analytical solution for large deflections of a clamped circular diaphragm with built-in stress is presented. The solution is directly applicable to micromachined pressure sensors. The solution is compared to finite element analysis results and experimental data from a surface-micromachined pressure sensor.
Date: March 9, 1999
Creator: Bitsie, F.; Eaton, W.P.; Plummer, D.W. & Smith, J.H.
Partner: UNT Libraries Government Documents Department

Micromachined pressure sensors: Review and recent developments

Description: Since the discovery of piezoresistivity in silicon in the mid 1950s, silicon-based pressure sensors have been widely produced. Micromachining technology has greatly benefited from the success of the integrated circuits industry, burrowing materials, processes, and toolsets. Because of this, microelectromechanical systems (MEMS) are now poised to capture large segments of existing sensor markets and to catalyze the development of new markets. Given the emerging importance of MEMS, it is instructive to review the history of micromachined pressure sensors, and to examine new developments in the field. Pressure sensors will be the focus of this paper, starting from metal diaphragm sensors with bonded silicon strain gauges, and moving to present developments of surface-micromachined, optical, resonant, and smart pressure sensors. Considerations for diaphragm design will be discussed in detail, as well as additional considerations for capacitive and piezoresistive devices.
Date: March 1, 1997
Creator: Eaton, W.P. & Smith, J.H.
Partner: UNT Libraries Government Documents Department

Comparison of bulk- and surface-micromachined pressure sensors

Description: Two piezoresistive micromachined pressure sensors were compared: a commercially available bulk-micromachined (BM) pressure sensor and an experimental surface-micromachined (SM) pressure sensor. While the SM parts had significantly smaller die sizes, they were outperformed in most areas by the BM parts. This was due primarily to the smaller piezoresistive gauge factor in the polysilicon piezoresistors in the SM parts compared to the single crystal strain gauge used in the BM parts.
Date: August 1, 1998
Creator: Eaton, W.P.; Smith, J.H.; Monk, D.J.; O`Brien, G. & Miller, T.F.
Partner: UNT Libraries Government Documents Department

Micromachined sensor and actuator research at the Microelectronics Development Laboratory

Description: An overview of the major sensor and actuator projects using the micromachining capabilities of the Microelectronics Development Laboratory at Sandia National Laboratories is presented. Development efforts are underway for a variety of micromechanical devices and control electronics for those devices. Surface micromachining is the predominant technology under development. Pressure sensors based on silicon nitride diaphragms have been developed. Hot polysilicon filaments for calorimetric gas sensing have been developed. Accelerometers based upon high-aspect ratio surface micromachining are under development. Actuation mechanisms employing either electrostatic or steam power are being combined with a three-level active (plus an additional passive level) polysilicon surface micromachining process to couple these actuators to external devices. Results of efforts toward integration of micromechanics with the driving electronics for actuators or the amplification/signal processing electronics for sensors is also described. This effort includes a tungsten metallization process to allow the CMOS electronics to withstand high-temperature micromechanical processing.
Date: December 1994
Creator: Smith, J. H.; Barron, C. C.; Fleming, J. G.; Montague, S.; Rodriguez, J. L.; Smith, B. K. et al.
Partner: UNT Libraries Government Documents Department

Calibration of manganin pressure gauges at 250 C

Description: During the past several decades manganin gauges have been used extensively for making in-situ high pressure measurements in materials under dynamic loading conditions. Prior to their use manganin gauges were calibrated but only under normal ambient temperatures. Recent interest in the behavior of both reactive and inert materials, when they were subjected to dynamic loading while being at high initial temperature, required a re-visit of the calibration procedure and reconfirmation of the gauges' proper behavior in such an extreme thermal environment. The paper describes the procedure of making such new calibrations of the existing manganin gauges and reports on the new findings. The Hugoniot for 6061-T6 aluminum at 250*C is also given.
Date: June 1, 1999
Creator: Forbes, J. W.; Garcia, F.; Tarver, C. M. & Uttiew, P. A.
Partner: UNT Libraries Government Documents Department