Experimental studies of sound pressure levels at the workplaces of operators of small-scale mechanization equipment when grinding rails

2021 ◽  
pp. 109-115
Author(s):  
A. A. Nazaretov ◽  
Keyword(s):  
Sound Pressure ◽  
Experimental Studies ◽  
Railway Track ◽  
Small Scale ◽  
Mechanical Processing ◽  
Rail Grinding ◽  
Noise Impact ◽  
Sound Pressure Levels ◽  
Grinding Machines ◽  
Grinding Machine

Intensive wear of rails in curves significantly reduces their service life, reduces the efficiency of operational work. A promising direction in solving this problem is the technology of rail grinding, which allows mechanical processing of the rail head without dismantling them in the conditions of a railway track. The article presents the results of studies of the noise impact on track workers when grinding rails by means of small mechanization-a rail-grinding machine SH-1, a grinding machine 2152D and a manual machine for grinding rails MRSH3. The analysis of various layouts of rail grinding machines, their features, technical characteristics and octave levels of sound pressure when these machines are running at idle and under load was carried out. According to the results of experimental studies, graphical dependences of the sound pressure levels of rail grinding machines are constructed, the excess of the noise level over the permissible sanitary standards in the area of rail grinding by means of small mechanization is revealed.

EXPERIMENTAL STUDIES ON THE NOISE AND VIBRATION OF A SPECIAL BORING MACHINE DUE TO FORMATION OF THE OPERATOR´S WORKPLACE SOUND FIELD

Akustika ◽  
2019 ◽  
Vol 34 ◽  
pp. 100-103
Author(s):  
Alexander Shashurin ◽  
Marat Goguadze ◽  
Anna Lubianchenko
Keyword(s):  
Theoretical Analysis ◽  
Sound Pressure ◽  
Experimental Studies ◽  
Sound Radiation ◽  
Sound Field ◽  
Noise Levels ◽  
Noise And Vibration ◽  
Measurement Results ◽  
Sound Pressure Levels ◽  
Excessive Noise

The purpose of this study is to measure the octave sound pressure levels and vibrations of a boring machine. A theoretical analysis of the sound pressure levels near the boring machine is performed. The measurement results are given. It was found that the workplace sound pressure levels exceed the sanitary standards, which suggests that the excessive noise levels are due to the exposure to the cutter sound radiation and the axis being machined.

Experimental Studies on the Effects of Nozzle Structures on Characteristics of Submerged Gas Jet Noise

2012 ◽  
Vol 204-208 ◽  
pp. 4620-4623 ◽  
Author(s):  
Zong Rui Hao ◽  
Zhong Hai Zhou
Keyword(s):  
Cross Sections ◽  
Sound Pressure ◽  
Experimental Studies ◽  
Flow Characteristics ◽  
Jet Noise ◽  
Gas Jet ◽  
Frequency Bands ◽  
Sound Levels ◽  
Sound Pressure Levels ◽  
Liquid Flows

The structures of nozzle outlet have great effects on jet noise generated by submerged gas jet. Five nozzles with different cross-sections were designed to study the influences of nozzle structures on sound levels by experimental methods. The flow characteristics and sound pressure levels were measured and the gas-liquid flows formed by submerged gas jets under different Weber numbers were also observed. The results show that the gas-liquid flows transformed from bubbling regime to jetting regime with the increase of Weber numbers. With respect to bubbling flow, no significant differences in sound levels for different nozzles were found. However, a remarkable increase of acoustic emission was caused by the transformation of flow patterns over the frequency bands of 0.6-4 kHz for all nozzles. In addition, sound pressure levels for elliptical nozzle were much lower than those of other nozzles over the frequency bands of 0.6-4 kHz. Therefore, it would be a reasonable strategy to adopt several elliptical orifices instead of round nozzle to reduce the gas jet noise in the design of underwater exhaust muffler.

DETERMINATION OF THE NOISE POWER GENERATED BY THE POWDER SUPERSONIC JETS (SSJ)

Akustika ◽  
2020 ◽  
Vol 36 (36) ◽  
pp. 17-21
Author(s):  
Anatoly Kochergin ◽  
Valeeva Ksenia
Keyword(s):  
Solid Fuel ◽  
Sound Pressure ◽  
Experimental Studies ◽  
Supersonic Jet ◽  
Acoustic Power ◽  
Small Scale ◽  
Noise Power ◽  
Rocket Engines ◽  
Pressure Pulsations

The paper analyzes the results of experimental studies of the parameters of acoustic fields generated by the jets of small-scale solid fuel rocket engines (SFRE). The field of isobars of sound pressure created by a supersonic jet (SSJ) is considered. To identify the most correct approach to determining the acoustic power of the SSJ, a numerical integration of the power of pressure pulsations along the length of the jet was performed.

THEORETICAL STUDY OF NOISE GENERATION DURING DRILLING OF WOOD WORKPIECES WITH REGARD TO THE DRILL FEED RATE

Akustika ◽  
2021 ◽  
pp. 183-185
Author(s):  
Dmitry Ruslyakov
Keyword(s):  
Feed Rate ◽  
Metal Cutting ◽  
Sound Pressure ◽  
Theoretical Study ◽  
Experimental Studies ◽  
Drilling Process ◽  
Noise Generation ◽  
Circular Saw ◽  
Sound Pressure Levels ◽  
Milling Machines

In contrast to metal-cutting machines, woodworking machines are characterized not only by sound pressure levels at the operators’ workplaces that exceed the sanitary standards, but also by dust concentrations that also exceed the standards. At present, a set of theoretical and experimental studies has been carried out and engineering solutions have been proposed to bring vibroacoustic characteristics and dustiness to the sanitary standards for woodworking thickness-jointing machines, band and circular saw machines, model and contour-milling machines. Studies of this kind in relation to woodworking drilling machines have not been done. It should be noted that not only the layout of woodworking drilling machines, but also the dynamics of the drilling process has significant differences from the above mentioned machines.

Real Ear Sound Pressure Levels Developed by Three Portable Stereo System Earphones

1992 ◽  
Vol 1 (4) ◽  
pp. 52-55 ◽  
Author(s):  
Gail L. MacLean ◽  
Andrew Stuart ◽  
Robert Stenstrom
Keyword(s):  
High Frequency ◽  
Sound Pressure ◽  
Low Frequency ◽  
Test System ◽  
Output Frequency ◽  
Frequency Effects ◽  
Adult Men ◽  
Frequency Responses ◽  
Significant Difference ◽  
Sound Pressure Levels

Differences in real ear sound pressure levels (SPLs) with three portable stereo system (PSS) earphones (supraaural [Sony Model MDR-44], semiaural [Sony Model MDR-A15L], and insert [Sony Model MDR-E225]) were investigated. Twelve adult men served as subjects. Frequency response, high frequency average (HFA) output, peak output, peak output frequency, and overall RMS output for each PSS earphone were obtained with a probe tube microphone system (Fonix 6500 Hearing Aid Test System). Results indicated a significant difference in mean RMS outputs with nonsignificant differences in mean HFA outputs, peak outputs, and peak output frequencies among PSS earphones. Differences in mean overall RMS outputs were attributed to differences in low-frequency effects that were observed among the frequency responses of the three PSS earphones. It is suggested that one cannot assume equivalent real ear SPLs, with equivalent inputs, among different styles of PSS earphones.

Personal Audio System: Hearing Symptoms, Habits, and Sound Pressure Levels Measured in Real Ear and a Manikin

2020 ◽  
Vol 63 (6) ◽  
pp. 2016-2026
Author(s):  
Tamara R. Almeida ◽  
Clayton H. Rocha ◽  
Camila M. Rabelo ◽  
Raquel F. Gomes ◽  
Ivone F. Neves-Lobo ◽  
...  
Keyword(s):  
Sound Pressure ◽  
Daily Basis ◽  
Cross Sectional Study ◽  
Normal Hearing ◽  
Chi Square ◽  
Cross Sectional ◽  
The Real ◽  
Significant Difference ◽  
Sound Pressure Levels ◽  
Audio System

Purpose The aims of this study were to characterize hearing symptoms, habits, and sound pressure levels (SPLs) of personal audio system (PAS) used by young adults; estimate the risk of developing hearing loss and assess whether instructions given to users led to behavioral changes; and propose recommendations for PAS users. Method A cross-sectional study was performed in 50 subjects with normal hearing. Procedures included questionnaire and measurement of PAS SPLs (real ear and manikin) through the users' own headphones and devices while they listened to four songs. After 1 year, 30 subjects answered questions about their usage habits. For the statistical analysis, one-way analysis of variance, Tukey's post hoc test, Lin and Spearman coefficients, the chi-square test, and logistic regression were used. Results Most subjects listened to music every day, usually in noisy environments. Sixty percent of the subjects reported hearing symptoms after using a PAS. Substantial variability in the equivalent music listening level (Leq) was noted ( M = 84.7 dBA; min = 65.1 dBA, max = 97.5 dBA). A significant difference was found only in the 4-kHz band when comparing the real-ear and manikin techniques. Based on the Leq, 38% of the individuals exceeded the maximum daily time allowance. Comparison of the subjects according to the maximum allowed daily exposure time revealed a higher number of hearing complaints from people with greater exposure. After 1 year, 43% of the subjects reduced their usage time, and 70% reduced the volume. A volume not exceeding 80% was recommended, and at this volume, the maximum usage time should be 160 min. Conclusions The habit of listening to music at high intensities on a daily basis seems to cause hearing symptoms, even in individuals with normal hearing. The real-ear and manikin techniques produced similar results. Providing instructions on this topic combined with measuring PAS SPLs may be an appropriate strategy for raising the awareness of people who are at risk. Supplemental Material https://doi.org/10.23641/asha.12431435

First description of a glass sponge reef soundscape reveals fish calls and elevated sound pressure levels

2018 ◽  
Vol 595 ◽  
pp. 245-252 ◽  
Author(s):  
SK Archer ◽  
WD Halliday ◽  
A Riera ◽  
X Mouy ◽  
MK Pine ◽  
...  
Keyword(s):  
Sound Pressure ◽  
Glass Sponge ◽  
Sound Pressure Levels ◽  
Sponge Reef
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