scholarly journals The assessment of the sawmill noise

2013 ◽  
Vol 44 (2s) ◽  
Author(s):  
P. D’Antonio ◽  
C. D’Antonio ◽  
C. Evangelista ◽  
V. Doddato
Keyword(s):  
Data Processing ◽  
Sound Pressure Level ◽  
Noise Level ◽  
Sound Pressure ◽  
Sound Level ◽  
Pressure Level ◽  
Published Data ◽  
Noise Levels ◽  
Different Types ◽  
Level Meter

Noise is a serious and widespread problem in many workplaces like in sawmill. The published data for the year 2010 about the total number of pathologies from work in Italia due to the noise, showed 5222 cases divided by sex, in fact for females there are instances in number of 221 while the male has a number of cases is equal to 4961. The aim of this work was to detect the sound level caused by the use of the machineries in a sawmill. The measurements were carried out through an instrument known as noise level meter, equipped with a microphone and connected to a computer for data processing and analysis of variance to a factor in excel, and able to assess noise levels at any particular point in the mill. The machines were subjected in relief and with several different types of wood materials. Obviously, in our case a fundamental role takes the moisture of wood. The drying operation is intended to obtain that degree of humidity of the wood, generally it must be between 7 and 16%, compatible with the type of glue used and, above all, appropriate to the target structures. The machines that have the highest sound pressure levels were trimmer and profiler, with values ranging between 85 dB(A) and 110 dB(A). Finally, it’s possible conclude that the sound pressure level increases when the aspiration equipment is turned on, the noise of machinery decreases during the processing of wood and that, increasing the thickness, decreased the noise emitted by the machine.

Research on the Vibration Measurement Approach to the On-Line Noise Evaluation for Vehicle Transmissions

2012 ◽  
Vol 562-564 ◽  
pp. 1163-1167
Author(s):  
Feng Qiang Zhao ◽  
Guang Qiang Li ◽  
Hong Ying Hu ◽  
Jia Lu Du ◽  
Chen Guo
Keyword(s):  
Sound Pressure Level ◽  
Production Line ◽  
Background Noise ◽  
Sound Pressure ◽  
Sound Level ◽  
Pressure Level ◽  
Vibration Measurement ◽  
Vehicle Transmissions ◽  
Quality Of Transmission ◽  
Level Meter

At present, the common method of testing noise generated by vehicle transmission before delivery is to measure the noise sound pressure level by means of sound level meter. Since the measurement result is susceptible to background noise, the method can only be operated in anechoic chamber. In this paper, in order to measure sound pressure level directly on production-line, a new vibration measurement method and its relevant formula are presented. The proposed method can effectively avoid being affected by background noise and obtain the sound pressure level of transmission noise on production-line by testing the vibration acceleration signals of transmission box. It’s proved that the new method makes the delivery test of transmission noise more convenient and effective. Moreover, it can improve the delivery quality of transmission as well as the performance of whole vehicle.

scholarly journals Analysis of Noise Level Generated by Stone Cutter Machine

2018 ◽  
Vol 3 (1) ◽  
pp. 53 ◽  
Author(s):  
Lindawati Lindawati ◽  
Nuzuli Fitriadi ◽  
Afdhal Afdhal
Keyword(s):  
Sound Pressure Level ◽  
Noise Level ◽  
Background Noise ◽  
Large Scale ◽  
Sound Pressure ◽  
Sound Level ◽  
Pressure Level ◽  
Production Unit ◽  
Cutting Machine ◽  
Background Noise Level

Marble, one of natural stone, has been widely produced since the last decade. In South Aceh, Marble stone is fabricated at Marble Production Unit that is located around Polytechnic of Aceh Selatan. The using of large-scale stone-cutting machines in Marble Production process tends to be a major noise source in Polytechnic of Aceh Selatan environment. The aim of this study is to analyze the noise level generated by Marble Cutting Machine in Marble Production Unit. The noise levels were analyzed by measuring Background Noise Level (BNL) and Sound Pressure Level (SPL). Sound Level Meter Type SL-814 was employed in the measurement. The results show that Background Noise Level measured is 53.03 dB on average. The highest Sound Pressure Level measured when the marble cutting machine was operated without workpiece is 94dB. In addition, the highest sound pressure level measured when marble cutting machine was operated with the workpiece is 96 dB. The values have generally exceeded the Threshold Noise Level allowed for education area, 55 dB. The noisy condition in campus environment would have an impact on teaching and learning processes within the Polytechnic of South Aceh.

scholarly journals Acoustic and Flow Aspects of Novel Synthetic Jet Actuator

Actuators ◽  
2020 ◽  
Vol 9 (4) ◽  
pp. 100 ◽  
Author(s):  
Emil Smyk ◽  
Paweł Gil ◽  
Rafał Gałek ◽  
Łukasz Przeszłowski
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Optimal Solution ◽  
Sound Level ◽  
Pressure Level ◽  
Synthetic Jet ◽  
Acoustic Properties ◽  
Synthetic Jet Actuator ◽  
Flow Parameters ◽  
Level Meter

The acoustic and flow aspects of the novel synthetic jet actuator (SJA) with fins inside the cavity were experimentally investigated for three types of enclosure design and two models of loudspeaker. The aim of the study is to find the parameter which connects the flow and acoustic properties of the SJA and allows us to choose the optimal solution in those regards. The hot wire anemometry was used for the velocity measurements and the sound pressure level was measured with a sound level meter. The model of the loudspeaker turned out to have a significantly stronger impact on the flow parameters and noise level than the shape of the fins in the cavity. The parameter that showed a dependence on the shape of the fins was the actuator’s efficiency. A ratio of the root-mean-square velocity at the orifice axis to the sound pressure level (U0.c/SPL) was used to connect the acoustic and flow properties of the tested actuators. This parameter was subsequently applied to determine the best configuration among the tested actuators.

scholarly journals Noise Pollution on an Acute Surgical Ward

2008 ◽  
Vol 90 (2) ◽  
pp. 136-139 ◽  
Author(s):  
Emma McLaren ◽  
Charles Maxwell-Armstrong
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Sound Level ◽  
Pressure Level ◽  
World Health ◽  
High Dependency Unit ◽  
Who Guidelines ◽  
Noise Levels ◽  
Coffee Shop ◽  
High Dependency

INTRODUCTION This study was undertaken to measure and analyse noise levels over a 24-h period on five general surgical wards. PATIENTS AND METHODS Noise levels were measured on three wards with four bays of six beds each (wards A, B and C), one ward of side-rooms only (ward D) and a surgical high dependency unit (ward E) of eight beds. Noise levels were measured for 15 min at 4-hourly intervals over a period of 24 h midweek. The maximum sound pressure level, baseline sound pressure level and the equivalent continuous level (LEq) were recorded. Peak levels and LEq were compared with World Health Organization (WHO) guidelines for community noise. Control measurements were taken elsewhere in the hospital and at a variety of public places for comparison. RESULTS The highest peak noise level recorded was 95.6 dB on ward E, a level comparable to a heavy truck. This exceeded all control peak readings except that recorded at the bus stop. Peak readings frequently exceeded 80 dB during the day on all wards. Each ward had at least one measurement which exceeded the peak sound level of 82.5 dB recorded in the supermarket. The highest peak measurements on wards A, B, C and E also exceeded peak readings at the hospital main entrance (83.4 dB) and coffee shop (83.4 dB). Ward E had the highest mean peak reading during the day and at night – 83.45 dB and 81.0 dB, respectively. Ward D, the ward of side-rooms, had the lowest day-time mean LEq (55.9 dB). Analysis of the LEq results showed that readings on ward E were significantly higher than readings on wards A, B and C as a group (P = 0.001). LEq readings on ward E were also significantly higher than readings on ward D (P < 0.001). Day and night levels differ significantly, but least so on the high dependency unit. CONCLUSIONS The WHO guidelines state that noise levels on wards should not exceed 30 dB LEq (day and night) and that peak noise levels at night should not exceed 40 dB. Our results exceed these guidelines at all times. It is likely that these findings will translate to other hospitals. Urgent measures are needed to rectify this.

Research of Possibilities of Using the Recycled Materials Based on Rubber and Textiles Combined with Vermiculite Material in the Area of ​​Noise Reduction

2014 ◽  
Vol 1001 ◽  
pp. 171-176 ◽  
Author(s):  
Pavol Liptai ◽  
Marek Moravec ◽  
Miroslav Badida
Keyword(s):  
Absorption Coefficient ◽  
Standing Wave ◽  
Sound Pressure Level ◽  
Sound Absorption ◽  
Sound Pressure ◽  
Sound Level ◽  
Pressure Level ◽  
Sound Absorption Coefficient ◽  
Physical Parameters ◽  
Materials Research

This paper describes possibilities in the use of recycled rubber granules and textile materials combined with vermiculite panel. The aim of the research is the application of materials that will be absorbing or reflecting sound energy. This objective is based on fundamental physical principles of materials research and acoustics. Method of measurement of sound absorption coefficient is based on the principle of standing wave in the impedance tube. With a sound level meter is measured maximum and minimum sound pressure level of standing wave. From the maximum and minimum sound pressure level of standing wave is calculated sound absorption coefficient αn, which can take values from 0 to 1. Determination of the sound absorption coefficient has been set in 1/3 octave band and in the frequency range from 50 Hz to 2000 Hz. In conclusion are proposed possibilities of application of these materials in terms of their mechanical and physical parameters.

scholarly journals Status of noise pollution in urban area of Dharan Sub- Metropolitan City and Inaruwa Municipality of Sunsari District, Nepal

2017 ◽  
Vol 7 (1) ◽  
pp. 35-40
Author(s):  
Ranij Shrestha ◽  
Alankar Kafle ◽  
Kul Prasad Limbu
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Pollution Assessment ◽  
Noise Pollution ◽  
Pressure Level ◽  
Noise Levels ◽  
Night Time ◽  
Level Measurement ◽  
Standard Value ◽  
Autumn And Winter

The environmental noise level measurement in Dharan and Inaruwa cities of eastern Nepal were conducted and compared with the ambient noise standards provided by Government of Nepal. The noise pollution assessment was performed in autumn and winter seasons by the indicator average day time sound pressure level (Ld, during 7.00 to 22.00 hrs) and average night time sound pressure level (Ln, during 22.00 to 7.00 hrs). The Ld and Ln values at the commercial, silence and residential zones of Dharan were 78 to 82 and 72 to 73, 65 to 73 and 60 to 70, 65 to 76 and 62 to 64 dB(A) in autumn and 78 to 79 and 72 to 76, 64 to 71 and 58 to 68, 63 to 74 and 60 to 62 dB(A) in winter, respectively whereas for Inaruwa, measurement were 75 to 77 and 73 to 75, 59 and 57, 67 and 60 dB(A) in autumn and 66 to 70 and 63 to 68, 55 and 53, 65 and 58 dB(A) in winter, respectively. The results showed that noise levels exceeded the standard value at most of the sites.

scholarly journals Investigation of Noise Pollution Distribution in Different Parts of Yazd Textile Factories

2021 ◽  
Author(s):  
Mohammad Javad Zare Sakhvidi ◽  
Hamideh Bidel ◽  
Ahmad Ali Kheirandish
Keyword(s):  
Occupational Exposure ◽  
Sound Pressure Level ◽  
Textile Industry ◽  
Sound Pressure ◽  
Noise Pollution ◽  
Sound Level ◽  
Pressure Level ◽  
Cross Sectional ◽  
Sound Pressure Levels ◽  
Different Parts

 Background: Chronic occupational exposure to noise is an unavoidable reality in the country's textile industry and even other countries. The aim of this study was to compare the sound pressure level in different parts of the textile industry in Yazd and in different parts of the textile industry. Methods: This cross-sectional study was performed on 930 textile workers in Yazd. A questionnaire was used to obtain demographic information and how to use protective equipment. Then, to obtain the sound pressure level of each unit and device and to use the measurement principles, a calibrated sound level meter was used. Then the results were analyzed using SPSS Ver.29 software. Results: The participants in this study were 714 males and 216 females with a mean age of 35.27 and 33.63 years, respectively. Seven hundred fifty-six participants (81.29%) were exposed to sound pressure levels higher than 85 dB. Among the participants, only 18.39% of the people used a protective phone permanently. Except for factory E, with an average sound pressure level of 77.78 dB, the rest of the factories had an average sound pressure level higher than the occupational exposure limit. The sound measurement results of different devices show that the sound pressure levels above 90 dB are related to the parts of Dolatab, Ring, Kinetting (knitting), Chanel, Autoconer, Dolakni, Open End, MultiLakni, Tabandegi, Texture, and Poy. Conclusion: Based on the results of the present study, noise above 90 dB is considered as one of the main risk factors in most parts of the textile industry (spinning and weaving), which in the absence of engineering, managerial or individual controls on it causes hearing loss in becoming employees of this industry

scholarly journals Supersonic Windtunnel Noise Attenuation

2021 ◽  
Author(s):  
William Wai Lim Wong
Keyword(s):  
Wind Tunnel ◽  
Sound Pressure Level ◽  
Noise Level ◽  
Sound Pressure ◽  
Power Level ◽  
Mesh Size ◽  
Acoustic Power ◽  
Pressure Level ◽  
Supersonic Wind Tunnel ◽  
Acoustic Treatment

The aerodynamic generated noise in the supersonic wind tunnel during operation at Ryerson University has exceeded the threshold of hearing damage. An acoustic silencer was to be designed and added to the wind tunnel to reduce the noise level. The main sources of noise generated from the wind tunnel with the silencer were identified to be located at the convergent divergent nozzle and the turbulent region downstream of the shock wave at the diffuser with the maximum acoustic power level of the entire wind tunnel at 161.09 dB. The designed silencer provided an overall sound pressure level reduction of 21.41 db which was considered as acceptable. Refinement to the mesh size and changes to the geometry of the mixing chamber was suggested for a more accurate result in noise output as well as flow conditions would match up to the physical flow. Additional acoustic treatment should be applied to the wind tunnel to further reduce sound pressure level since the noise level still exceeded the threshold of hearing loss.

scholarly journals Assessment of traffic noise due to transverse rumble strips at residential areas

2018 ◽  
Vol 250 ◽  
pp. 02006
Author(s):  
Zaiton Haron ◽  
Darus Nadirah ◽  
Supandi Mohamad Afif ◽  
Yahya Khairulzan ◽  
Nordiana Mashros ◽  
...  
Keyword(s):  
Noise Level ◽  
Traffic Noise ◽  
Middle Layer ◽  
Sound Level ◽  
Skid Resistance ◽  
Residential Areas ◽  
Noise Levels ◽  
Traffic Characteristics ◽  
Level Meter ◽  
Road Characteristics

Transverse rumble strips (TRS) are commonly being installed to alert the drivers through sound and vibration effects. The sound produced affects the existing traffic noise level which caused noise annoyance to the nearby residents. This study aims to assess the traffic noise due to TRS at residential areas by determining the roadside noise levels, traffic and road characteristics and evaluating the relationship between these parameters. Middle overlapped (MO), middle layer overlapped (MLO) and raised rumbler (RR) TRS profiles with same thickness were selected. The measurements of roadside noise levels and skid resistance were conducted using sound level meter (SLM) and British pendulum tester (BPT) respectively. Traffic characteristics were evaluated using previous data measured using automatic traffic counter (ATC). In overall, MLO produced highest roadside noise levels with increase of 20.5dBA from baseline. Generally, the increase of roadside noise level due to TRS is strong with speed, weak to medium with skid resistance of TRS and no relationship with traffic volume. Based on three TRS profile types, MLO is not suitable to be installed on the roadways adjacent to the residential areas as the increase of roadside noise level is significant which is more than 5dBA compared to MO and RR.

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