Results 251 to 260 of about 109,970 (304)
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The Journal of the Acoustical Society of America, 1963
A lightweight impedance tube has been developed primarily as an instrument for practical research. It can be used also for precision measurements of acoustical-impedance and sound-absorption coefficients in both laboratory and field installations, over the frequency range 400 to 900 cps.
Raymond D. Berendt, Henry A. Schmidt
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A lightweight impedance tube has been developed primarily as an instrument for practical research. It can be used also for precision measurements of acoustical-impedance and sound-absorption coefficients in both laboratory and field installations, over the frequency range 400 to 900 cps.
Raymond D. Berendt, Henry A. Schmidt
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Simple Impedance Test for Eustachian Tube Function
Archives of Otolaryngology - Head and Neck Surgery, 1981A simple impedance method to evaluate Eustachian tube function has been reported. The principle of the test consists of recording the impedance of the eardrum during Valsalva's maneuver and during swallowing. By this procedure, the inflow and outflow of air through the tube is recorded as a simple pattern of impedance change that is classified into the
I, Honjo, T, Kumazawa, K, Honda
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A high-impedance, cold-cathode triger tube
IRE Transactions on Electron Devices, 1956The tube to be described is a cold-cathode, gas-filled tetrode which triggers on extremely low signals. It was developed by the Raytheon Manufacturing Company in cooperation with the Diamond Ordnance Fuze Laboratories. Under pre-firing conditions, the tube passes a very small Townsend current of about 10-9amp. On application of a firing signal, current
M.J. Reddan, P. Stutsman, N. Spencer
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Acoustic Impedance of Rectangular Tubes
The Journal of the Acoustical Society of America, 1953An expression for the acoustic impedance of a section of infinite parallel planes is derived. Measured values of the impedance of long narrow rectangular tubes show good agreement with this theory when an appropriate end correction is used. The theory compares favorably with impedance measurements on short rectangular tubes or slits even when the ...
John K. Wood, George B. Thurston
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Impedance Measurements of Inertance Tubes for Pulse Tube Cryocoolers
Advanced Materials Research, 2013The impedance of the inertance tubes which include the mass flows, pressure amplitudes and phase shifts between them at the inlet of the inertance tubes were measured by correcting the mass flows at the surface of the compressor piston. The experimental results are compared with the theoretical values based on simplified turbulent-flow thermoacoustic ...
S.S. Li, Y.N. Wu
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Impedance Measurements of Inertance Tubes
AIP Conference Proceedings, 2006The flow impedance of an inertance tube of 5.74 mm inside diameter and 2.36 m long coupled to various reservoir volumes was measured and compared with that predicted by a model based on a transmission line analogy. Though data at other average pressures and temperatures were obtained, this paper focuses on data taken with an average pressure of 2.5 MPa
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Coupling Impedance of Cylindrical Tubes
IEEE Transactions on Electromagnetic Compatibility, 1972The concept of a coupling (transfer) impedance as developed by Schelkunoff for cylindrical tubes is applied in the determination of the mutual coupling to a grounded coaxial cable. Formulas are developed utilizing the coupling impedance concept when the exciting, or interfering, circuit is either a single-wire line or another coaxial cable over a ...
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Traveling-Wave Tube Helix Impedance
Proceedings of the IRE, 1953The impedance parameter of a circular helix, from which the gain of a helix-type traveling wave amplifier is computed, is investigated for a "Tape-Helix" model. Results obtained in this paper indicate that the impedance has a smaller value than for the "Sheath-Helix" model, and is considerably reduced at larger values of ka, the ratio of the helix ...
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Development of an Indigenous Impedance Tube
Applied Mechanics and Materials, 2015Fabrication of an impedance tube for measuring sound absorption coefficient is presented in this paper. Transfer-function method is chosen for the sound absorption analysis. The impedance tube is designed and fabricated in accordance with ISO 10534-2. The tube is made from brass with diameter of 114.3 mm and length of 1.42 m.
Wei Hong Tan +4 more
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Comments on impedance tube measurements
The Journal of the Acoustical Society of America, 1981The application of a new impedance measuring method to water-filled tubes is discussed. It is shown that source reflections do not invalidate the method, and that valid results can be obtained at frequencies several times higher than that of the first cross mode of the tube.
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