Damping effect of HID lamp acoustic resonance by power input wave

A Frisbee with a mass of 0.21 kg, diameter of 0.27 m and moment of inertia (MOI) of 0.002 kg·m2 was instrumented with a triaxial gyroscope. The Frisbee was thrown at low angular velocities as the measurement limit of a single gyroscope was at 6.065 rps. The angular velocities of the triaxial gyroscope were analysed to study the attitude of a Frisbee before and after release. The angular velocities measured were post-processed and the following data were obtained: spin rate at release—3.9–6.14 rps; user-induced peak torque—0.483–0.9 Nm, and peak angular acceleration—204–358 rad/s2; and power input 7.53–19.56 W. The Frisbee wobbled at release which decreased during the flight due to a damping effect. This affected the spin decay, the reduction of wobble lead to a reduced drag force and thus to a smaller spin decay, which was initially 1.12–0.31 rev/s2 and then asymptoted to 0.11–0.01 rev/s2.

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Study of Damping Effect of Grass Like Crops

Volume 12: Micro and Nano Systems, Parts A and B ◽

10.1115/imece2009-13127 ◽

2009 ◽

Author(s):

Sushil Doranga ◽

Jiang Zhou ◽

Yubing Yang

Keyword(s):

Forced Vibration ◽

Life Support ◽

Vibration Suppression ◽

New Technology ◽

Power Input ◽

Structural Vibration ◽

Vibration Effect ◽

Damping Effect ◽

Resonant Effect ◽

The Difference

The objective of this study was to quantify the dynamic response of the living grass-like crops structure under free and forced vibration. The living grass-like crops may become the key component in a new technology which extract and make use of unwanted energy associated with structural vibration. The proposed procedure is firstly illustrated with a simulated example of the simple pendulum configuration with the tray holding the grass. Output of the vibrating grass is measured through frequency analyzer (FFT Analyzer). The relative decay of the amplitude of vibration is used to measure the damping effect of grass. Secondly, forced vibration effect is studied by designing the slider crank mechanism over a frequency range from 0.7 to 1.7Hz. Resonant effect is studied. The difference in the acceleration, velocity, and displacement between the vibration tray loaded with the crop and the tray without the crop for the same power input will measure the vibration suppression capabilities of grass-like crops. The result of the experiments quantifies this damping effect and extrapolates the data to estimate the effects of a crop-based life support system on a spacecraft.

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Assessment of Tongue Position and Laryngeal Height in Two Professional Voice Populations

Journal of Speech Language and Hearing Research ◽

10.1044/2019_jslhr-19-00164 ◽

2020 ◽

Vol 63 (1) ◽

pp. 109-124

Author(s):

Carly Jo Hosbach-Cannon ◽

Soren Y. Lowell ◽

Raymond H. Colton ◽

Richard T. Kelley ◽

Xue Bao

Keyword(s):

Vocal Fold ◽

Vocal Tract ◽

Current Knowledge ◽

Acoustic Resonance ◽

Contact Dynamics ◽

Voice Disorder ◽

Music Program ◽

Tongue Position ◽

Singer Groups ◽

Professional Voice

Purpose To advance our current knowledge of singer physiology by using ultrasonography in combination with acoustic measures to compare physiological differences between musical theater (MT) and opera (OP) singers under controlled phonation conditions. Primary objectives addressed in this study were (a) to determine if differences in hyolaryngeal and vocal fold contact dynamics occur between two professional voice populations (MT and OP) during singing tasks and (b) to determine if differences occur between MT and OP singers in oral configuration and associated acoustic resonance during singing tasks. Method Twenty-one singers (10 MT and 11 OP) were included. All participants were currently enrolled in a music program. Experimental procedures consisted of sustained phonation on the vowels /i/ and /ɑ/ during both a low-pitch task and a high-pitch task. Measures of hyolaryngeal elevation, tongue height, and tongue advancement were assessed using ultrasonography. Vocal fold contact dynamics were measured using electroglottography. Simultaneous acoustic recordings were obtained during all ultrasonography procedures for analysis of the first two formant frequencies. Results Significant oral configuration differences, reflected by measures of tongue height and tongue advancement, were seen between groups. Measures of acoustic resonance also showed significant differences between groups during specific tasks. Both singer groups significantly raised their hyoid position when singing high-pitched vowels, but hyoid elevation was not statistically different between groups. Likewise, vocal fold contact dynamics did not significantly differentiate the two singer groups. Conclusions These findings suggest that, under controlled phonation conditions, MT singers alter their oral configuration and achieve differing resultant formants as compared with OP singers. Because singers are at a high risk of developing a voice disorder, understanding how these two groups of singers adjust their vocal tract configuration during their specific singing genre may help to identify risky vocal behavior and provide a basis for prevention of voice disorders.

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ACOUSTIC RESONANCE PHENOMENA IN BYPASS CHANNELS FOR AIR IN AVIATION ENGINES

Прикладная механика и техническая физика ◽

10.15372/pmtf20160602 ◽

2016 ◽

Keyword(s):

Acoustic Resonance ◽

Resonance Phenomena ◽

Aviation Engines

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Prediction of acoustic resonance in tandem cascades

10.2514/6.1998-2252 ◽

1998 ◽

Cited By ~ 1

Author(s):

B. Woodley ◽

N. Peake

Keyword(s):

Acoustic Resonance ◽

Tandem Cascades

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A review of high-power magnetoplasmodynamic electric propulsion designs and studies of RSC Energia

Space engineering and technology ◽

10.33950/spacetech-2308-7625-2020-4-112-133 ◽

2020 ◽

pp. 112-133

Author(s):

Victor V. SINYAVSKIY

Keyword(s):

Service Life ◽

Electric Power ◽

High Power ◽

Electric Propulsion ◽

Nuclear Power ◽

Materials Science ◽

Low Voltage ◽

Power Input ◽

Design Bureau ◽

Rocket Propulsion

At the initiative of S.P.Korolev, in 1959, Special Design Bureau No.1 (now RSC Energia) established the High-temperature Power Engineering and Electric Propulsion Center which was tasked with development of nuclear electric propulsion for heavy interplanetary vehicles. Selected as the source of electric power was a nuclear power unit based on a thermionic converter reactor, and selected as the engine was a stationary low-voltage magnetoplasmodynamic (MPD) high-power (0.5–1.0 MW) thruster which had thousands of hours of service life. The paper presents the results of extensive efforts in research, development, design, materials science experiments, and tests on the MPD-thruster, including the results of development and 500-hours life tests of an MPD-thruster with a 500-600 kW electric power input that used lithium propellant. The world’s first lithium 17 kW MPD-thruster was built and successfully tested in space. The paper points out that to this day nobody has surpassed the then achievements of RSC Energia neither in thruster output during long steady-state operation, nor in performance and service life. Key words: Martian expeditionary vehicle, nuclear electric rocket propulsion system, electric rocket thruster, magnetoplasmodynamic thruster, lithium, cathode, anode, barium, electric propulsion tests in space.

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