scholarly journals Helicopter Inside Cabin Acoustic Evaluation: A Case Study—IAR PUMA 330

2021 ◽  
Vol 18 (18) ◽  
pp. 9716
Author(s):  
Marius Deaconu ◽  
Grigore Cican ◽  
Adina-Cristina Toma ◽  
Luminița Ioana Drăgășanu
Keyword(s):  
Noise Exposure ◽  
Flight Test ◽  
Noise Levels ◽  
Noise Sources ◽  
High Noise ◽  
Measurement Campaign ◽  
Measurement Results ◽  
Noise Assessment ◽  
Acoustic Evaluation

This paper presents an inside-cabin acoustic evaluation of the IAR PUMA 330 helicopter, manufactured by IAR S.A. Brasov. In this study, based on the acoustic assessment inside the helicopter, areas with high noise levels are identified. In this regard, several tests were carried out in accordance with the ISO 5129 standard. In the first stage of the assessment, a measurement campaign was performed to identify the acoustic leaks from the outside noise sources propagating inside the cabin (in the door area) and the acoustic attenuation of the helicopter structure. These tests were performed on the factory runway, with the helicopter in parked position (ground tests). During the ground tests, the helicopter engines were turned off. The tests consisted of placing two loudspeakers directed towards the helicopter door and generating pink noise. Inside the helicopter, the entire door frame opening was scanned with an intensity probe to identify acoustic leaks areas. The second assessment stage was to determine the areas of the cabin with the highest levels of noise. Within the measurement campaign, 16 microphones were placed inside the cabin, at the level of the passengers’ heads, arranged in seven zones. The tests were carried out with the helicopter engines started, staying at fixed point above the ground (hovering), and then a flight test, in which all the maneuvers necessary for the use of the helicopter were performed (in-flight tests). Based on the measurement results, it was possible to highlight the noise spectral components in each of the seven areas. The noise assessment revealed high noise levels inside the cabin, having as main noise sources the transmission gear and the door area, leading to the need for reducing the noise exposure for passengers and crew, thus the need to reduce noise levels inside the helicopter.

S254 – Bone Conduction Noise Exposure via Ventilators in the NICU

2008 ◽  
Vol 139 (2_suppl) ◽  
pp. P160-P160
Author(s):  
Angela P Black ◽  
James D Sidman
Keyword(s):  
Ambient Noise ◽  
Noise Exposure ◽  
Bone Conduction ◽  
Sound Level ◽  
Noise Levels ◽  
High Noise ◽  
Endotracheal Tubes ◽  
Level Meter ◽  
Hearing Damage ◽  
Air Conduction

Objectives To demonstrate that neonatal ventilators produce high noise levels through bone conduction (BC) via endotracheal tubes, as well as air conduction (AC) from ambient noise. Methods A sound level meter was used to measure the noise levels 4 feet from the ventilator and in direct contact at the end of a balloon attached to the ETT to simulate the noise presented to the infant. 3 commonly used neonatal ventilators (Sensormedics 3100A, VIP Bird and Bunnell Jet) were examined. Results Noise levels were significantly higher (6 – 14 dB) at the end of the ETT than 4 ft from the ventilator for all ventilators studied. Conclusions Previous studies have shown high ambient noise levels in NICUs, but have failed to address the actual noise presented to the infant. ETT transmission of noise as a direct bone stimulus through the skull has been overlooked. This study has shown that high noise intensities are being presented not only as AC, but as BC to the infants though the ETT. This study demonstrates, therefore, that ear protection alone will not save these at-risk infants from hearing damage. More must be done to decrease noise exposure and develop quieter machines.

scholarly journals Noise Descriptors For Kota Metropolis, Rajasthan (India)

2021 ◽  
Vol 16 (1) ◽  
pp. 176-189
Author(s):  
Kuldeep Kuldeep ◽  
Sohil Sisodiya ◽  
Dr. Anil K. Mathur
Keyword(s):  
Noise Level ◽  
Noise Exposure ◽  
Noise Pollution ◽  
Pollution Level ◽  
Exposure Index ◽  
Noise Levels ◽  
Rapid Urbanization ◽  
High Noise ◽  
Sampling Locations ◽  
The City

The most common environmental concern in metropolitan cities worldwide is noise pollution. Kota metropolis (India) is also suffering from the problem of the increased noise level in the urban environment. Kota metropolis has been selected for the assessment of noise pollution. The main reasons behind the increasing level of noise in the city are increased population, rapid urbanization and industrialization, increased transportation facilities, urban development, construction and demolition works etc. The noise levels were recorded for day-time (6 am to 10 pm) as per Indian standard time for 96 days. Sixteen sampling points are made within the city depending upon the category of area/zone such as industrial, residential, silence and commercial. Six days were prescribed for each sampling location for noise level measurement. Noise descriptors such as Lmax, Lmin, L10, L50, L90, NC (noise climate), Lnp (noise pollution level), Leq (equivalent noise level), and NEI (noise exposure index) were computed with the observed data. Noise descriptors are very useful to indicate the physiological and psychological effects of noise pollution associated with noise levels. It makes regulating agency to take necessary actions in high noise areas for noise vulnerable groups such as Childs, old persons etc. Noise levels were recorded with the digital sound level meter " HTC SL-1350". Obtained equivalent noise levels were in between 65 dB(A) to 85 dB(A). The results were then compared with the WHO standards of community noise levels, and Indian noise pollution standards. It is noticed that the noise levels in all monitoring stations were well above the limits of the standards prescribed by the WHO and CPCB. Small variations in noise levels were observed for all sampling locations i.e. noise levels were almost similar at sampling locations. Noise levels were distinct in magnitude for morning and evenings hours. Noise Exposure Index (NEI) was greater than 1 which shows significant high noise levels in all the sampling locations. Kota metropolis desperately needs new strategies to reduces the high noise level in the city. Regulating agencies should take necessary action before things get out of control. Some immediate actions are suggested in the study.

scholarly journals Field Study of the Noise Exposure Inside Running Metro Unit

2021 ◽  
Vol 7 (3) ◽  
pp. 560-574
Author(s):  
Mohamed N. Younes ◽  
Ali Z. Heikal ◽  
Akram S. Kotb ◽  
Haytham N. Zohny
Keyword(s):  
Noise Exposure ◽  
Sound Level ◽  
Noise Levels ◽  
Severe Damage ◽  
Acoustic Environment ◽  
Factors Affecting ◽  
Greater Cairo ◽  
Train Speed ◽  
Level Meter

The noise levels inside metro units are considered a significant problem that makes passengers suffer from severe damage, especially for those who use the metro periodically. This research evaluates the acoustic environment inside the metro car and studies factors affecting the noise levels inside metro units and developing models for estimate noise in the metro unit while moving between stations. Greater Cairo Metro (GCM) Line 1 has been selected as a case study. A sound level meter was used to measure the equivalent sound level in dBA and evaluate the noise inside metro units. The results indicate that the noise levels are unacceptable compared with the international noise exposure standards. The highest measured noise level inside metro units is 91.2 dBA. These unacceptable noise levels led to more investigation of factors that may affect noise levels inside metro units. Other data have been collected, such as the speed of the train and the track alignment details. The results showed that the noise increases with the increase of the train speed until the speed reaches a specific value, then it decreases depending on the maintenance status and the train type. In addition, the noise levels through curved underground tracks are higher than the levels along straight surface tracks by 18 dB(A). Doi: 10.28991/cej-2021-03091674 Full Text: PDF

scholarly journals Development of Airport Noise Mapping using Matlab Software (Case Study: Adi Soemarmo Airport – Boyolali, Indonesia)

2018 ◽  
Vol 31 ◽  
pp. 12007
Author(s):  
Pertiwi Andarani ◽  
Haryono Setiyo Huboyo ◽  
Diny Setyanti ◽  
Wiwik Budiawan
Keyword(s):  
Noise Level ◽  
Noise Exposure ◽  
Model Simulation ◽  
Develop Model ◽  
Noise Power ◽  
Noise Levels ◽  
Noise Mapping ◽  
Matlab Software ◽  
International Airport

Noise is considered as one of the main environmental impact of Adi Soemarmo International Airport (ASIA), the second largest airport in Central Java Province, Indonesia. In order to manage the noise of airport, airport noise mapping is necessary. However, a model that requires simple input but still reliable was not available in ASIA. Therefore, the objective of this study are to develop model using Matlab software, to verify its reliability by measuring actual noise exposure, and to analyze the area of noise levels‥ The model was developed based on interpolation or extrapolation of identified Noise-Power-Distance (NPD) data. In accordance with Indonesian Government Ordinance No.40/2012, the noise metric used is WECPNL (Weighted Equivalent Continuous Perceived Noise Level). Based on this model simulation, there are residence area in the region of noise level II (1.912 km2) and III (1.16 km2) and 18 school buildings in the area of noise levels I, II, and III. These land-uses are actually prohibited unless noise insulation is equipped. The model using Matlab in the case of Adi Soemarmo International Airport is valid based on comparison of the field measurement (6 sampling points). However, it is important to validate the model again once the case study (the airport) is changed.

Noise exposure and its impact on psychological health of agricultural tractor operators

2021 ◽  
Vol 69 (6) ◽  
pp. 500-506
Author(s):  
Muhammad Yamin ◽  
Zohaib Yousaf ◽  
Khalid Mahmood Bhatt ◽  
Muhammad Ibrahim
Keyword(s):  
Psychological Health ◽  
Noise Exposure ◽  
Noise Pollution ◽  
Psychological Problems ◽  
Noise Levels ◽  
High Noise ◽  
Adverse Health Effects ◽  
Negative Effect ◽  
Positive Correlations ◽  
Agricultural Tractor

Constant exposure of noise to the auditory system of the agricultural tractor opera- tor can cause physical and psychological problems. A field study was conducted in the Faisalabad and Narowal districts of Pakistan to examine the spread of tractor noise and its psychological effects on the safety of tractor operators driving tractors without cabins and other noise reduction measures. Four of the most common imple- ments used in Pakistan, including land scraper, cultivator, disk harrow and seed drill, were used to detect the changes in tractor noise at two speeds of 5.3 km/h and 10.6 km/h in all four directions. Lowest noise was produced during the field operation of the seed drill at a mean noise value of 81.9 dB(A) among all four implements. Disk harrow and cultivator were found to be the most noisy implement, and during oper- ation, the tractor operator was directly exposed to high noise levels of 86.9 dB(A) and 84.9 dB(A), respectively. This noise pollution caused psychological problems in agri- cultural tractor operators, as demonstrated by the highly positive correlations of de- pression, aggression, anxiety and stress. This trend had a negative effect on their social interactions relative to the comparable population of office employees. In or- der to mitigate the adverse health effects, tractor operators must be equipped with sound proof cabins or at least ear plugs because of direct exposure to high noise levels. Furthermore, a safe distance of 48 m or at least a warning distance of 26 m from the tractor must be maintained by farm workers.

Noise assessment of taxibotted versus conventional taxiing operations using a phased microphone array

2021 ◽  
Vol 263 (5) ◽  
pp. 1152-1163
Author(s):  
Bieke von den Hoff ◽  
Mirjam Snellen ◽  
Dick G. Simons
Keyword(s):  
Noise Source ◽  
Microphone Array ◽  
Noise Levels ◽  
Noise Sources ◽  
Operational Testing ◽  
Electric Aircraft ◽  
Noise Source Identification ◽  
Noise Measurements ◽  
Noise Assessment ◽  
Lower Noise

In sustainable aviation the focus is mostly applied to the greenhouse gas emissions during flight. However airports have an increasing interest in reducing emissions during ground operations such as taxiing for example to improve the local air quality. Amsterdam Airport Schiphol started a pilot for sustainable taxiing with a pilot-controlled hybrid-electric aircraft towing vehicle called TaxiBot in 2020. The COVID-19 pandemic created an opportunity for extensive operational testing on a near-empty airport. Due to the low background noise levels in this situation, also a noise assessment of taxiing with the TaxiBot versus conventional two-engine taxiing was performed. This assessment can be used to evaluate the noise levels to which ground workers or neighbouring communities are exposed due to TaxiBot operations. For the noise measurements a phased microphone array was used, which allowed not only for a noise level and directionality assessment, but also for noise source identification. This paper compares the noise emissions and noise sources between a taxibotted and conventional taxiing operation. The results show that a taxibotted taxiing operation produces significantly lower noise levels. Additionally, acoustic imaging shows that the TaxiBot engine is the main noise source for a taxibotted pass-by manoeuvre.

scholarly journals Acoustic Environment and Noise Exposure in Fitness Halls

2020 ◽  
Vol 10 (18) ◽  
pp. 6349
Author(s):  
Omaimah Ali Al-Arja
Keyword(s):  
Noise Level ◽  
Noise Exposure ◽  
Subjective Rating ◽  
Reverberation Time ◽  
Noise Levels ◽  
Acoustic Environment ◽  
Exposure Limit ◽  
Raising Awareness ◽  
Measurement Results ◽  
T Values

People seek health and leisure in gyms and fitness halls. In this study, interior acoustics including reverberation time (T) and activity noise levels were studied in 20 indoor sports and gymnasium (IS & G) halls in Amman, Jordan. Interviews and questionnaires were also applied to assess the subjective comfort levels of the acoustic environment in these IS & G halls. The measured values were correlated with the subjective evaluations. The range of measured T values was 1.09–5.38 s. The activity noise level, which was measured with LA,eq over 50 min of activity, ranged between 80.0 and 110.0 dB(A). The average personal noise exposure for instructors was 92.6 dB(A), ranging from 81.0 to 108.0 dB(A), whereas 90% of the measurement results were above the occupational exposure limit (OEL) of 85.0 dB(A), and 40% of instructors were potentially exposed to excessive noise levels. The subjective rating of listening conditions correlated significantly with the reverberation time rather than noise level (p < 0.01). In conclusion, the results from this study show that noise levels generated in the studied IS & G halls present a possible workplace noise hazard. Raising awareness of the risk of hearing problems among instructors working in IS & G halls is highly recommended.

scholarly journals Case study: A survey of perceived noise in Canadian multi-unit residential buildings to study long-term implications for widespread teleworking

2021 ◽  
pp. 1351010X2199374 ◽  
Author(s):  
Maedot S. Andargie ◽  
Marianne Touchie ◽  
William O’Brien
Keyword(s):  
Large Scale ◽  
Noise Exposure ◽  
Residential Buildings ◽  
Well Being ◽  
Ability To Work ◽  
Noise Sources ◽  
Work From Home ◽  
Research Opportunity

Trends of urbanization, densification, and telework all point to increasing exposure to ambient noise for workers. With the lockdown policies implemented in response to COVID-19, a research opportunity to study perceived noise exposure for teleworking arose. This paper presents the results of a survey on noise issues in multi-unit residential buildings (MURBs) and the consequent effects on occupants' well-being and productivity during the lockdown. Responses were collected from 471 MURB occupants across Canada. The results show that, despite the decrease in environmental noise, many are annoyed by outdoor noise, particularly from traffic and construction activities, and indicated that it affects their ability to work. Effects on ability to work from home were more frequently reported for indoor noise sources particularly airborne and impact noises coming from neighboring suites. Our findings, however, show that noise coming from occupants in the same suite (i.e. roommates and family) present the biggest issue. The findings indicate that existing noise conditions in MURBs might not be suitable for a permanent large-scale implementation of teleworking.

scholarly journals How Loud are Noise Levels of Baseball Stadium? Assessment of Noise Levels and Attitude toward the Stadium Noise in Korea

2019 ◽  
Author(s):  
Donguk Lee ◽  
Woojae Han
Keyword(s):  
Noise Exposure ◽  
Sound Level ◽  
Noise Levels ◽  
Low Frequencies ◽  
High Noise ◽  
Survey Sample ◽  
Level Meter ◽  
Hearing Damage ◽  
Baseball Fans ◽  
Question Survey

This study measures the noise levels in a baseball stadium and analyzes baseball fans&rsquo; attitude of effect of recreational noise exposure on their hearing. In the baseball stadium, noise levels were measured in four seating sections using a sound level meter during the games. The LAeq average of the 16 measures produced 91.7 dBA, showing a significantly high noise level in the red and navy sections. As a function of frequency by LZeq analysis, the noise levels were significantly higher in low frequencies than other frequencies. For the survey sample, 688 randomly selected participants completed a 16-question survey on their noise exposure during the game and on the potential risk of hearing loss. Despite the very high noise levels, 70% of the respondents preferred sitting in either the red or the navy section to be closer to the cheerleaders and to obtain a good view. Most respondents reported that they did not consider wearing earplugs, and one-third experienced hearing muffled speech after the game. We conclude that the noise levels in baseball stadiums are high enough to cause hearing damage and/or tinnitus later, but expect these results to improve public education regarding safe noise exposure during popular sports activities.

scholarly journals Design of Prototype Aircraft Noise Monitoring System Using Microcontroller

2021 ◽  
Vol 2 (2) ◽  
pp. 87-92
Author(s):  
Ahmad Ridwan ◽  
Triyanto Pangaribowo
Keyword(s):  
Monitoring System ◽  
Power Unit ◽  
Internet Protocol ◽  
Aircraft Noise ◽  
Noise Levels ◽  
Noise Sources ◽  
Ip Address ◽  
Auxiliary Power Unit ◽  
Auxiliary Power ◽  
Measurement Results

This paper was presented a design of aircraft noise monitoring system using microcontroller. This system is for monitoring noise levels to make it easier to analyze and measure noise that can be accessed remotely. The measurement results are accessed through a browser with IP address access (Internet Protocol) from the local server esp32 and also OLED 0.96 inc. Taking the noise value for 10 seconds with data samples every 1 second with aircraft noise sources consisting of APU (Auxiliary Power Unit), dual pack on and engine motoring. With each noise value of 61.5 dB, 75.6 dB and 82.5 dB.

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