OCDs Reliability Screening Using Normalization Variance of Noise Spectrum

2011 ◽  
Vol 130-134 ◽  
pp. 72-75
Author(s):  
Qiu Zhan Zhou ◽  
Jian Gao ◽  
Na Lei ◽  
Dan’e Wu
Keyword(s):  
Screening Method ◽  
Low Frequency ◽  
Noise Spectrum ◽  
Previous Method ◽  
New Method ◽  
Excess Noise ◽  
Frequency Noise ◽  
Related Characteristic ◽  
The Relationship ◽  
Large Frequency

Considering the inflexibility and limitations of the traditional frequency-domain OCDs reliability screening method using noise parameters at fixed frequency-points, we put forward a new method using the normalization variance of a large frequency-band noise spectrum in this paper. The possible sources of excess noise in OCDs and the relationship between low-frequency noise and reliability are studied at first, and then we describe the detailed process of the method for reliability screening, including the normalization method of noise spectrum, the calculations of variance and related characteristic quantities. At last, compare the screening results obtained by both of the previous method and this new method, and it demonstrated that this method is much more accurate and reliable.

NEW ETIOLOGICAL FACTORS OF OCCUPATIONAL HEARING LOSS

2021 ◽  
Author(s):  
V.B. Pankova ◽  
◽  
М.F. Vilk ◽  
◽  
◽  
...  
Keyword(s):  
Hearing Loss ◽  
Low Frequency ◽  
Evidence Base ◽  
Frequency Noise ◽  
Labor Intensity ◽  
Etiological Factors ◽  
Hearing Organ ◽  
The Relationship ◽  
Vascular Stria ◽  
Occupational Hearing Loss

Annotation. On the example of railway and air transport, a number of new issues of occupational hearing loss are shown, requiring study and subsequent implementation in practical health care, as new etiological factors in the development of hearing loss. This concerns the factor of labor intensity, which has a potentiating, pathogenetic significance, along with noise, in the development of hearing loss due to the formation of chronic stress, leading to additional ischemia of the vascular stria and damage to the neuroepithelium of the inner ear. There is a need, along with the development of a methodology for assessing the factor of labor intensity for SOUT of workplaces, to determine the criteria for its negative action when used for the examination of the connection between the disease of the organ of hearing and the profession. In the «List of occupational diseases» in clause 2.4.2. indicated diseases associated with exposure to infrasound (IZ), among the manifestations of which, called sensorineural hearing loss bilateral. However, IZ, as well as low-frequency noise (LFN), were not previously considered as significant adverse factors in relation to the hearing organ in mass clinical trials, therefore, there are no expert criteria for the relationship between hearing loss and their impact, which could be applied in practice, which requires accumulation of evidence base for the subsequent substantiation of an independent nosological form of a disease of the organ of hearing, associated with mechanoacoustic exposure.

scholarly journals The Relationship between Vibratory Sensation and Body Surface Vibration Induced by Low-Frequency Noise

2002 ◽  
Vol 21 (2) ◽  
pp. 87-100 ◽  
Author(s):  
Yukio Takahashi ◽  
Kazuo Kanada ◽  
Yoshiharu Yonekawa
Keyword(s):  
Body Surface ◽  
Mechanical Vibration ◽  
Low Frequency ◽  
The Body ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Vibration Acceleration ◽  
Surface Vibration ◽  
Human Body Surface ◽  
The Relationship

Human body surface vibration induced by low-frequency noise was measured at the forehead, the chest and the abdomen. At the same time, subjects rated their vibratory sensation at each of these locations. The relationship between the measured vibration on the body surface and the rated vibratory sensation was examined, revealing that the vibratory sensations perceived in the chest and abdomen correlated closely with the vibration acceleration levels of the body surface vibration. This suggested that a person exposed to low-frequency noise perceives vibration at the chest or abdomen by sensing the mechanical vibration that the noise induces in the body. At the head, on the other hand, it was found that the vibratory sensation correlated comparably with the vibration acceleration level of the body surface vibration and the sound pressure level of the noise stimulus. This finding suggested that the mechanism of perception of vibration in the head is different from that of the perception of vibratory sensation in the chest and the abdomen.

A new method with an explant culture of the utricle for assessing the influence of exposure to low-frequency noise on the vestibule

2020 ◽  
Vol 83 (5) ◽  
pp. 215-218
Author(s):  
Nobutaka Ohgami ◽  
Tingchao He ◽  
Reina Oshino-Negishi ◽  
Yishuo Gu ◽  
Xiang Li ◽  
...  
Keyword(s):  
Low Frequency ◽  
Explant Culture ◽  
New Method ◽  
Frequency Noise ◽  
Low Frequency Noise

scholarly journals Development of an on-site system for measuring the low-frequency noise and complainant’s responses

2018 ◽  
Vol 37 (2) ◽  
pp. 373-384
Author(s):  
Hiroshi Sato ◽  
Jongkwan Ryu ◽  
Kenji Kurakata
Keyword(s):  
Time Trends ◽  
Sound Pressure ◽  
Low Frequency ◽  
Dominant Frequency ◽  
Pressure Level ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Measurement Results ◽  
Frequency Components ◽  
The Relationship

An on-site system for measuring low-frequency noise and complainant's responses to the low-frequency noise was developed to confirm whether the complainant suffer from the environmental noise with low-frequency components. The system suggests several methods to find the dominant frequency and major sound pressure level spectrum of the noise causing annoyance. This method can also yield a quantified relationship (correlation coefficient and percentage of response to the noise) between physical noise properties and the complainant’s responses. The advantage of this system is that it can easily find the relationship between the complainant’s response to the acoustic event of the houses and the physical characteristics of the low-frequency noise, such as the time trends and frequency characteristics. This paper describes the developed system and provides an example of the measurement results.

Noise Test and Countermeasures Research of Locomotive Cab

2011 ◽  
Vol 317-319 ◽  
pp. 1197-1200
Author(s):  
Yan Liu ◽  
Wen Liu ◽  
Bing Yang ◽  
Xiao Pai Zhang ◽  
Ping Zhang ◽  
...  
Keyword(s):  
Low Frequency ◽  
Good Health ◽  
Electrical Equipment ◽  
Intermediate Frequency ◽  
Noise Spectrum ◽  
Channel Noise ◽  
Frequency Noise ◽  
Frequency Range ◽  
Noise Test ◽  
Analysis System

The locomotive cab noise has became an important factor in good health of the drivers through analyzing noise hazards of the locomotive cab, and the noise also can reduce working efficiency, easy to produce hidden trouble on security. Use Multi-channel Noise Test and Analysis System, measure the locomotive cab noise and analyze the results of the noise test, then get the conclusions from the noise spectrum: Locomotive cab noise occurs mainly in the low frequency range and intermediate frequency range; Wheel-rail noise and cooling room noise mainly are low frequency noise; Electrical equipment of the first locomotive cab contribute a major noise. Results of this study provide the basis for the vibration and noise reduction design of the locomotive cab.

Efficiency of an ANC system in the tractor cabin under controlled engine workload

2020 ◽  
Vol 68 (5) ◽  
pp. 339-357
Author(s):  
Roberto Fanigliulo ◽  
Lindoro Del Duca ◽  
Laura Fornaciari ◽  
Renato Grilli ◽  
Roberto Tomasome ◽  
...  
Keyword(s):  
Sound Pressure ◽  
Noise Control ◽  
Active Noise Control ◽  
Low Frequency ◽  
Engine Performance ◽  
Noise Spectrum ◽  
Broadband Noise ◽  
Frequency Noise ◽  
Residual Noise ◽  
Agricultural Tractor

The noise at the driver seat of an agricultural tractor is produced mostly by the engine. Its characteristic broadband noise spectrum varies considerably with engine workload. The passive noise control techniques adopted in tractor cabins, based on the application of sound-absorbing and sound-proofing materials, are effective against medium-high frequencies noise components. The residual noise in sound-proof cabins is characterized by tonal emissions with low frequency components (< 500 Hz) but regarded as responsible for various disorders and diseases following long-term exposure. In addition to the "A" weighting filter adopted to evaluate occupational exposure to noise, other approaches are reported in the scientific literature considered more appropriate to evaluate low frequency noise (LFN), as well as studies testifying the effectiveness of active noise control (ANC) technologies in the low frequency range. In this article, the performance of an ANC system is evaluated in its ability to reduce noise levels inside the soundproof cabin of an agricultural tractor. To test this system, spectro-phonometric measurements of the equivalent linear sound pressure level were conducted under controlled and repeatable engine workloads, obtained by connecting the tractor to a dynamometric brake, while simultaneously acquiring the related engine performance curves. Altogether, three different couples of loudspeakers were tested. Frequency analysis in one-third octave band showed that the ANC system was mainly effective against LFN components (below 120 Hz) with peaks of reduction up to 20 dB. Then, on the basis of indications from previous studies, the data of linear sound pressure levels were processed applying the "A", "B", and "C" weighting filters, to show the different emphasis given to the effects of the system. Eventually, a point-by-point composition of the equivalent levels of sound pressure was drawn over the whole range of the engine, to highlight the conditions in which the ANC system was more effective.

scholarly journals Effects of low-frequency noise from wind turbines on heart rate variability in healthy individuals

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Chun-Hsiang Chiu ◽  
Shih-Chun Candice Lung ◽  
Nathan Chen ◽  
Jing-Shiang Hwang ◽  
Ming-Chien Mark Tsou
Keyword(s):  
Heart Rate ◽  
Heart Rate Variability ◽  
Wind Turbines ◽  
Mixed Model ◽  
Low Frequency ◽  
Frequency Noise ◽  
Low Frequency Noise ◽  
Residential Communities ◽  
Field Campaigns ◽  
The Relationship

AbstractWind turbines generate low-frequency noise (LFN, 20–200 Hz), which poses health risks to nearby residents. This study aimed to assess heart rate variability (HRV) responses to LFN exposure and to evaluate the LFN exposure (dB, LAeq) inside households located near wind turbines. Thirty subjects living within a 500 m radius of wind turbines were recruited. The field campaigns for LFN (LAeq) and HRV monitoring were carried out in July and December 2018. A generalized additive mixed model was employed to evaluate the relationship between HRV changes and LFN. The results suggested that the standard deviations of all the normal to normal R–R intervals were reduced significantly, by 3.39%, with a 95% CI = (0.15%, 6.52%) per 7.86 dB (LAeq) of LFN in the exposure range of 38.2–57.1 dB (LAeq). The indoor LFN exposure (LAeq) ranged between 30.7 and 43.4 dB (LAeq) at a distance of 124–330 m from wind turbines. Moreover, households built with concrete and equipped with airtight windows showed the highest LFN difference of 13.7 dB between indoors and outdoors. In view of the adverse health impacts of LFN exposure, there should be regulations on the requisite distances of wind turbines from residential communities for health protection.

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