Study of measured indoor low-frequency noise levels resulting from outdoor noise sources, using a simplified physical model as well as empirical and FEM calculations

Low-frequency noise of the structures with Ge-nanoclusters of rather high surface density grown on the oxidized silicon surface is investigated for the first time. It was revealed that the 1/f γ noise, where γ is close to unity, is the typical noise component. Nevertheless, the 1/f γ noise sources were found to be distributed nonuniformly upon the oxidized silicon structure with Ge-nanoclusters. The noise features revealed were analyzed in the framework of widely used noise models. However, the models used appeared to be unsuitable to explain the noise behavior of the structures studied. The physical processes that should be allowed for to develop the appropriate noise model are discussed.

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Recurrence Plot Analysis of HRV for Exposure to Low-Frequency Noise

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.1044-1045.1251 ◽

2014 ◽

Vol 1044-1045 ◽

pp. 1251-1257 ◽

Cited By ~ 3

Author(s):

Shih Tsung Chen ◽

Chia Yi Chou ◽

Li Ho Tseng

Keyword(s):

Low Frequency ◽

Cardiovascular Responses ◽

Recurrence Plot ◽

Frequency Noise ◽

Cardiovascular Activity ◽

Low Frequency Noise ◽

Noise Levels ◽

Noise Condition ◽

Plot Analysis ◽

Recurrence Plot Analysis

Previous studies have indicated that the chronic effects of exposure to low-frequency noise causes annoyance. However, during the past two decades, most studies have employed questionnaires to characterize the effects of noise on psychosomatic responses. This study investigated cardiovascular activity changes in exposure to low-frequency noise for various noise intensities by using recurrence plot analysis of heart rate variability (HRV) estimation. The authors hypothesized that distinct noise intensities affect cardiovascular activity, which would be reflected in the HRV and recurrence quantification analysis (RQA) parameters. The test intensities of noises were no noise, 70-dBC, 80-dBC, and 90-dBC. Each noise level was sustained for 5 min, and the electrocardiogram (ECG) was recorded simultaneously. The cardiovascular responses were evaluated using RQA of the beat-to-beat (RR) intervals obtained from ECG signals. The results showed that the mean RR interval variability and mean blood pressure did not substantially change relative to the noise levels. However, the length of the longest diagonal line (Lmax) of the RQA of the background noise (no noise) condition was significantly lower than the 70-dBC, 80-dBC, and 90-dBC noise levels. The laminarity showed significant changes in the noise levels of various intensities. In conclusion, the RQA-based measures appear to be an effective tool for exposure to low-frequency noise, even in short-term HRV time series.

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LES Predictions of Jet Noise for a Pylon-Mounted Dual Stream Nozzle and Jet Surface Interactions

Volume 2A: Turbomachinery ◽

10.1115/gt2016-58175 ◽

2016 ◽

Cited By ~ 2

Author(s):

P. Vogel ◽

J. Bin ◽

N. Sinha

Keyword(s):

Supersonic Jet ◽

Low Frequency ◽

Frequency Noise ◽

Low Frequency Noise ◽

Acoustic Source ◽

Noise Sources ◽

Surface Time ◽

Acoustic Source Localization ◽

Jet Nozzle ◽

Field Noise

An end-to-end LES/FW-H noise prediction model has been demonstrated and validated with acoustic and flowfield data from a dual stream nozzle with pylon experiment conducted at NASA GRC using their Jet Engine Simulator (JES) geometry. Results show a large region of high turbulent kinetic energy (TKE) in the wake of the pylon. Acoustic Source Localization (ASL) studies using our numerical phased array methodology show this wake region to be the principle location of low frequency noise sources while higher frequency sources occur nearer to the nozzle lips. Numerical simulations have also been conducted on Jet-Surface Interaction (JSI) effects of a supersonic jet exhausting parallel to a finite surface. Time-averaged LES data and far-field noise predictions have been obtained for multiple surface locations as well as for an isolated jet nozzle. For upstream observers located below the surface, results show an increase in low-frequency noise over what was predicted for the isolated nozzle due to JSI effects and decrease in high-frequency noise due to shielding. This was significantly more pronounced for an over-expanded jet than for an under-expanded jet, an effect that was primarily attributed to the shorter core length of the over-expanded jet.

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Low Frequency Noise Analysis in Advanced CMOS Devices

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.324.441 ◽

2011 ◽

Vol 324 ◽

pp. 441-444 ◽

Cited By ~ 6

Author(s):

Jalal Jomaah ◽

Majida Fadlallah ◽

Gerard Ghibaudo

Keyword(s):

Experimental Data ◽

Noise Analysis ◽

Low Frequency ◽

Deep Submicron ◽

Electrical Noise ◽

Frequency Noise ◽

Low Frequency Noise ◽

Noise Sources ◽

The Impact ◽

Mobility Fluctuations

A review of recent results concerning the low frequency noise in modern CMOS devices is given. The approaches such as the carrier number and the Hooge mobility fluctuations used for the analysis of the noise sources are illustrated through experimental data obtained on advanced CMOS generations. Furthermore, the impact on the electrical noise of the shrinking of CMOS devices in the deep submicron range is also shown.

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Proposed Criteria for Low Frequency Industrial Noise in Residential Communities

Journal of Low Frequency Noise Vibration and Active Control ◽

10.1260/0263092054530957 ◽

2005 ◽

Vol 24 (2) ◽

pp. 97-105 ◽

Cited By ~ 2

Author(s):

George F. Hessler

Keyword(s):

United States ◽

Low Frequency ◽

The United States ◽

Frequency Noise ◽

Low Frequency Noise ◽

Residential Areas ◽

Noise Sources ◽

Residential Communities ◽

Open Cycle ◽

Industrial Sources

There is a need in the United States for some Federal or prominent standards organization to publish limits in residential areas for low frequency noise attributable to industrial sources. This paper proposes maximum limits based on experience in investigating and solving low frequency noise problems, principally from open cycle combustion turbine installations The author believes the recommended C-weighted limits in this paper are applicable to most common steady low-frequency noise sources in addition to combustion turbines due to the combined tonal and broadband character of the sound. It is hoped standardizing bodies can add this reference to the larger body of literature to arrive at a workable sorely-needed standard.

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