Field Experiment of a Sonic Crystal Window

2018 ◽  
Vol 17 (04) ◽  
pp. 1850032 ◽  
Author(s):  
Hsiao Mun Lee ◽  
Long Bin Tan ◽  
Kian Meng Lim ◽  
Jinlong Xie ◽  
Heow Pueh Lee
Keyword(s):  
Field Experiment ◽  
White Noise ◽  
Sound Quality ◽  
Sitting Position ◽  
Frequency Range ◽  
National University ◽  
Sonic Crystal ◽  
Narrow Frequency Range ◽  
Recorded Data

In the present study, white, pink, construction and environmental noises were evaluated in a student hostel at National University of Singapore (NUS) with a newly designed sonic crystal (SC) window using sound quality head and torso simulator. The sound head was placed at the bed and the chair in the student hostel. All recorded data were analyzed into full (100–7000[Formula: see text]Hz) and narrow (700–1400[Formula: see text]Hz) frequency ranges. For lying position and for white noise, the SC window was able to attenuate extra 6.7 and 9.5[Formula: see text]dBA of noise compared to the existing glass louver window for full and narrow frequency ranges, respectively. For full frequency range, the overall amounts of pink, construction and environmental noises attenuated by the SC window were about 4.8, 5.0 and 3.4[Formula: see text]dBA, respectively. For narrow frequency range, the overall amounts of these three type of noises attenuated by the SC window were about 2–3.9[Formula: see text]dBA higher than that of full frequency range. The overall amounts of attenuated white noise at sitting position were about 2.6 and 6.1[Formula: see text]dBA, respectively, for full and narrow frequency ranges. For full frequency range, the attenuated pink and construction noises at sitting position were about 3.8 and 4.8[Formula: see text]dBA, respectively, which were slightly lower than that at lying position. However, for narrow frequency range, the attenuated noises obtained at lying position were 2.7 and 2.5[Formula: see text]dBA higher than that at sitting position for pink and construction noises, respectively.

Environmental Noise Mitigation by Plenum Window with Sonic Crystals and Jagged Flap

2019 ◽  
Vol 18 (01) ◽  
pp. 1950001 ◽  
Author(s):  
Hsiao Mun Lee ◽  
Andi Haris ◽  
Kian Meng Lim ◽  
Jinlong Xie ◽  
Heow Pueh Lee
Keyword(s):  
White Noise ◽  
Experimental Studies ◽  
Environmental Noise ◽  
Noise Attenuation ◽  
Frequency Range ◽  
Noise Mitigation ◽  
Numerical Studies ◽  
Narrow Frequency Range ◽  
Sonic Crystals

A plenum window with incorporation of rectangular sonic crystals (SCs) in between two glass panes was tested in a reverberation room. Before the start of the experiment, numerical studies were performed on the whole structure in order to prove the effectiveness of the SCs in enhancing the noise attenuation performance of the plenum window. The effects of flat and jagged flaps on reducing strength of diffracted sound were also investigated in the experimental studies. White, traffic and construction noises were examined during each measurement. When the frequencies were ranging from 100[Formula: see text]Hz to 5000[Formula: see text]Hz, the plenum window with SCs without flap was able to attenuate 9.5, 8.5 and 8.6[Formula: see text]dBA of white, traffic and construction noises, respectively, compared with the case of without window. The effects of flat flaps on noise attenuation performance of the plenum window were negligible while the jagged flap was able to attenuate additional 1.7[Formula: see text]dBA of white noise and 1.6[Formula: see text]dBA of traffic and construction noises compared with the case of without flap. In the narrow frequency range of 900–1300[Formula: see text]Hz, the plenum window with SCs without flap was able to reduce additional 2.7, 2.3 and 2.5[Formula: see text]dBA of white, traffic and construction noises, respectively, compared with the case of without SCs.

Alerting and Message Components in Songs of Rufous-Sided Towhees

Behaviour ◽  
1981 ◽  
Vol 76 (3-4) ◽  
pp. 223-249 ◽  
Author(s):  
Douglas G. Richards
Keyword(s):  
Signal Detection Theory ◽  
Field Experiments ◽  
Species Recognition ◽  
Defense Responses ◽  
Time Of Arrival ◽  
Sufficient Information ◽  
Passerine Birds ◽  
Frequency Range ◽  
Narrow Frequency Range ◽  
Species Specific

AbstractIn numerous species of passerine birds the initial few notes of the song have a narrow frequency range and wide temporal spacing when compared with the rest of the song. This structure is well adapted for high detectability when the song is acoustically degraded during passage through the environment. The song of the rufous-sided towhee (Pipilo eythrophtalmus) consists of relatively tonal introductory syllables followed by a complex rapid trill. The trill is capable of carrying more information than the introduction, but is inherently less detectable at a distance owing to degradation by reverberation, amplitude fluctuation, and frequency-dependent attenuation. Signal detection theory predicts that the detectability of the trill will be increased when it is preceded by the introductory syllables, owing to the removal of uncertainty concerning the time of arrival of the signal. This is alerted detection. I performed field experiments using playback of recorded song to towhees to test the hypothesis that these introductory syllables facilitate detection of conspecific song at a distance. Tape recordings of normal and artificially degraded full songs, introduction, and trills were played to territorial male towhees. Normal songs, degraded songs, and normal trills elicited strong territorial defense responses, indicating recognition as adequate species-specific song, and confirming that sufficient information is contained in the trill for species recognition. Degraded trills alone elicited little response. Both normal and degraded introductions also elicited little response, demonstrating that the increased response to a degraded full song over that to a degraded trill is not due to any species-specific characteristics of the introduction, but rather to its function as an alerting stimulus.

scholarly journals Solving Noise Pollution Issue Using Plenum Window with Perforated Thin Box

Crystals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 614
Author(s):  
Hsiao Mun Lee ◽  
Andi Haris ◽  
Kian Meng Lim ◽  
Jinlong Xie ◽  
Heow Pueh Lee
Keyword(s):  
White Noise ◽  
Traffic Noise ◽  
Noise Pollution ◽  
Experimental Results ◽  
Frequency Range ◽  
Noise Mitigation ◽  
Noise Sources ◽  
Acoustic Performance ◽  
Common Noise ◽  
The Common

In the present study, a conventional plenum window was incorporated with perforated thin box in order to enhance its performance at frequency range which centralized at 1000 Hz as most of the common noise sources at city nowadays are centralizing around this frequency. The entire studies were conducted in a reverberation room. The effectiveness of jagged flap on mitigating diffracted sound was also studied. Three types of noises were examined in the current study—white noise, traffic noise and construction noises. The experimental results showed that the plenum window with perforated thin box could reduce 8.4 dBA, 8.7 dBA and 6.9 dBA of white, traffic and construction noises, respectively. The jagged flaps did not have significant effect on the plenum window’s noise mitigation performance. When frequencies were ranging from 800 Hz to 1250 Hz, when compared with the case of without perforated thin box, it was found that the perforated thin box had good acoustic performance where it was able to reduce additional 1.6 dBA, 1.6 dBA and 1.2 dBA of white, construction and traffic noises, respectively.

scholarly journals Multi-Frequency Synthesis

1991 ◽  
Vol 131 ◽  
pp. 171-179
Author(s):  
J. E. Conway
Keyword(s):  
Frequency Synthesis ◽  
Frequency Range ◽  
Image Fidelity ◽  
Narrow Frequency Range ◽  
Multiple Frequencies

AbstractA method of improving image fidelity by using observations at multiple frequencies is described. We discuss the power and possible limitations of the technique. Results of narrow frequency range observations with MERLIN and global VLBI are presented. We conclude with a consideration of the possible future impact of this technique.

Design of Discretely Tunable Resonant Actuators Using Additive Inertial Units

2019 ◽  
Vol 142 (3) ◽  
Author(s):  
Thomas W. Secord ◽  
Troy R. Louwagie ◽  
Robert J. Kopas
Keyword(s):  
General Framework ◽  
Voice Coil Motor ◽  
Energy Requirements ◽  
Frequency Range ◽  
Optimization Scheme ◽  
General Utility ◽  
Theoretical Design ◽  
Narrow Frequency Range ◽  
Resonant Actuators ◽  
Good Agreement

Abstract Resonance is known to reduce the input energy requirements of various actuator systems. The favorable effects of resonance, however, are limited to a narrow frequency range. To overcome this limitation, we describe a general framework for using discrete units of inertia that can be activated in a binary sense to move a resonant frequency across a desired frequency range. We also enumerate the generalized physical cases in which actuators can energetically benefit from resonance. We develop closed-form optimal results for the idealized case of two binary additive inertial units and extend this to a general optimization scheme for higher numbers of units that introduce parasitic friction and added stiffness. We illustrate the concept of binary tuning with a representative linear translational system powered by a voice coil motor (VCM). The experimental results show good agreement with the intended theoretical design and show the general utility of the binary additive inertia approach.

Dynamic transduction properties of in situ baroreceptors of rabbit aortic depressor nerve

1998 ◽  
Vol 274 (1) ◽  
pp. H358-H365 ◽  
Author(s):  
Takayuki Sato ◽  
Toru Kawada ◽  
Toshiaki Shishido ◽  
Hiroshi Miyano ◽  
Masashi Inagaki ◽  
...  
Keyword(s):  
Transfer Function ◽  
White Noise ◽  
Innominate Artery ◽  
Operating Pressure ◽  
Frequency Range ◽  
Aortic Depressor Nerve ◽  
The Right ◽  
Common Carotid Arteries ◽  
Made In

We developed a new method for isolating in situ baroreceptor regions of the rabbit aortic depressor nerve (ADN) and estimated the transfer function from pressure to afferent nerve activity in the frequency range of 0.01–5 Hz by a white noise technique. Complete isolation of the baroreceptor area of the right ADN was made in situ by ligation of the innominate artery and the right subclavian and common carotid arteries. We altered the pressure in the isolated baroreceptor area according to a binary quasi-white noise between 80 and 100 mmHg in 12 urethan-anesthetized rabbits. The gain increased two to three times as the frequency of pressure perturbation increased from 0.01 to 2 Hz and then decreased at higher frequencies. The phase slightly led below 0.2 Hz. The squared coherence value was >0.8 in the frequency range of 0.01–4 Hz. The step responses estimated from the transfer function were indistinguishable from those actually observed. We conclude that the baroreceptor transduction of the ADN is governed by linear dynamics under the physiological operating pressure range.

scholarly journals Optimal Design of a High Efficiency LLC Resonant Converter with a Narrow Frequency Range for Voltage Regulation

Energies ◽  
2018 ◽  
Vol 11 (5) ◽  
pp. 1124 ◽  
Author(s):  
Junhao Luo ◽  
Junhua Wang ◽  
Zhijian Fang ◽  
Jianwei Shao ◽  
Jiangui Li
Keyword(s):  
Optimal Design ◽  
High Efficiency ◽  
Voltage Regulation ◽  
Resonant Converter ◽  
Frequency Range ◽  
Llc Resonant Converter ◽  
Narrow Frequency Range

scholarly journals Overtone focusing in biphonic tuvan throat singing

eLife ◽  
2020 ◽  
Vol 9 ◽  
Author(s):  
Christopher Bergevin ◽  
Chandan Narayan ◽  
Joy Williams ◽  
Natasha Mhatre ◽  
Jennifer KE Steeves ◽  
...  
Keyword(s):  
Sound Production ◽  
Vocal Tract ◽  
Low Frequency ◽  
Resonance Imaging ◽  
Frequency Range ◽  
Vocal Cords ◽  
Singing Style ◽  
Narrow Frequency Range ◽  
The Republic ◽  
Throat Singing

Khoomei is a unique singing style originating from the republic of Tuva in central Asia. Singers produce two pitches simultaneously: a booming low-frequency rumble alongside a hovering high-pitched whistle-like tone. The biomechanics of this biphonation are not well-understood. Here, we use sound analysis, dynamic magnetic resonance imaging, and vocal tract modeling to demonstrate how biphonation is achieved by modulating vocal tract morphology. Tuvan singers show remarkable control in shaping their vocal tract to narrowly focus the harmonics (or overtones) emanating from their vocal cords. The biphonic sound is a combination of the fundamental pitch and a focused filter state, which is at the higher pitch (1–2 kHz) and formed by merging two formants, thereby greatly enhancing sound-production in a very narrow frequency range. Most importantly, we demonstrate that this biphonation is a phenomenon arising from linear filtering rather than from a nonlinear source.

The Colouring of White Noise

1974 ◽  
Vol 2 (5) ◽  
pp. 280-282 ◽  
Author(s):  
A. J. Kalnajs ◽  
B. A. Peterson
Keyword(s):  
White Noise ◽  
Tape Recorder ◽  
The Other ◽  
Frequency Range

The Mount Stromio optical pulsar detection equipment is built around a commercial two-track tape recorder: one track records timing pulses, and the other the pulses from a photomultiplier (Peterson 1974). Because of the modest frequency range of the recorder, it has been necessary to introduce a scaler between the recorder and photomultiplier in order to cope with bright sources.

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