Research of Different Noise Barriers Efficiency at Different Temperature

2017 ◽  
Author(s):  
Tomas Vilniškis ◽  
Tomas Januševicius
Keyword(s):  
Air Temperature ◽  
Noise Level ◽  
Structural Changes ◽  
Field Measurements ◽  
Sound Waves ◽  
Noise Barriers ◽  
Different Temperatures ◽  
Noise Measurements ◽  
Noise Barrier ◽  
Key Aspects

In this article was analyzed acoustic efficiency of two different construction noise barriers. Field measurements of noise tests were carried out before and behind a wooden barrier, which height was 2.9 meters and a wooden wall with equipped roof, which height was 3.2 m. As is known the length of the wall, height, surface roughness, shape and material of the wall – key aspects of determining the effectiveness of noise barrier. Different materials, depending on their characteristics of the hard or soft, porous or dense, interact differently with the sound of waves. Article contains research results of noise measurements at positive and negative air temperature. There analyzing wooden noise barrier acoustic efficiency at different temperatures and the effects of temperature to the diffraction of sound waves through the peak of the barrier. Test results show, that noise barrier without structural changes reduced noise level to 14–22 dB, noise barrier with structural changes reduced noise level to 20–23,1 dB, when air temperature was positive. When air temperature was negative, noise barrier without structural changes reduced noise level to 15,5–21,4 dB, noise level with structural changes to 19–26,6 dB.

scholarly journals Operational Noise Assessment in an Open Cycle Power Plant: Study on the Existing Acoustical Performance.

2018 ◽  
Vol 7 (4.35) ◽  
pp. 11 ◽  
Author(s):  
Helmi A Halim ◽  
Gasim Hayder
Keyword(s):  
Power Plant ◽  
Noise Level ◽  
Performance Study ◽  
Noise Barriers ◽  
Noise Assessment ◽  
Noise Barrier ◽  
Open Cycle ◽  
Gas Turbine Power Plant ◽  
The Impact

This research is an acoustical performance study in an open cycle peaking gas turbine power plant located at the southern coast of Peninsula Malaysia. Referring to its location at the middle of residence and tourism area, throughout its operation years, several complains from public has been lodged about the excessive operational noise at the perimeter of the plant and statistically from the last decade, twenty-four (24) noise related public complains were recorded. This issue has initiated a study to determine the current operational noise level as well as the effectiveness of the existing noise barriers. Based on EIA approval, the boundary noise for the operation should be limited to 55 dB(A) at any time. The field measurement of noise level at two (2) different locations are assessed in-situ and continuously noise monitoring covering all the plant’s operational regime and at different plant operational pattern. These results are compared with the initial noise report during its early year of operation in 1999. Finally the hypotheses then compared with the referenced legislations. Results from all the methodologies show the current operational noise level of the plant are within the permissible limit, however the overall operational noise of the plant is increasing compared with 1999 report due to the increasing of surrounding activities as well as deteriorating of current engineering and natural noise barrier arrangement. Mitigation plans has been recommended to the management to minimize the impact of the excessive noise to surrounding residence and to the plant workers. On top of that, the theoretical and commercial implication of the research is also discussed.

scholarly journals The study for installing noise barrier on highway route no.9

2018 ◽  
Vol 169 ◽  
pp. 01012
Author(s):  
Chaddanai Jiradecha ◽  
Pruethipong Singhatiraj
Keyword(s):  
Traffic Congestion ◽  
Noise Level ◽  
Noise Pollution ◽  
Mathematic Model ◽  
Rapid Expansion ◽  
Noise Barriers ◽  
Sensitive Areas ◽  
The People ◽  
Noise Barrier ◽  
A New Technique

Highway Route No. 9 is a Bangkok bypass motorway that aims to alleviate traffic congestion in greater Bangkok areas. Presently, it is found a rapid expansion of new communities residing along both side of Highway No. 9. To lessen the noise level, Department of Highways installed the noise barrier on the sensitive locations. However, people from communities living on both sides of highway still demand some additional noise pollution improvement. To improve the efficiency of using noise barriers and to promote environmental and social quality for the people on the sensitive communities along the highway route, the Department of Highways, therefore, designs a new technique for installing noise barrier on the sensitive areas, i.e. education institutions, temple, residential area. In addition, the mathematic model is applied to 12 selected locations of sensitive areas for monitoring the effectiveness of the new installation technique. The mathematic model is used for predict the future noise level after installation of noise barrier in year 2037. The results confirm that the appropriate height and width of noise barrier can improve the comfortable of the people on the sensitive area.

Performance of Noise Barriers with Absorptive Edge Treatments

2003 ◽  
Vol 1859 (1) ◽  
pp. 53-64
Author(s):  
Sanghoon Suh ◽  
Vincent J. Badagnani ◽  
Luc Mongeau ◽  
J. Stuart Bolton
Keyword(s):  
Traffic Noise ◽  
Field Measurements ◽  
Sound Level ◽  
Noise Model ◽  
Scale Model ◽  
Vertical Edge ◽  
Laboratory Measurements ◽  
Shadow Zone ◽  
Noise Barriers ◽  
Noise Barrier

The installation of sound-absorptive materials near the edge of a noise barrier is known to increase its insertion loss. First, scale-model experiments were performed to compare the performance of barriers that have absorptive edge linings with that of linearly extended, rigid uniform barriers and T-shaped barriers. The issue of effective positioning of the sound-absorptive material was also addressed. It was found that in terms of material use, an absorptive treatment was the most effective treatment for reducing the sound level in the shadow zone for a given barrier height. It was concluded that absorptive edge treatments may offer the opportunity to design effective treatments that could be retrofitted to existing barrier installations to improve their effectiveness. Preliminary field measurements were performed near South Bend, Indiana. The performance of an existing barrier was evaluated. Predictions of its performance made using the FHWA Traffic Noise Model were verified. An acoustical treatment was added to one vertical edge of the highway noise barrier. The results for the performance of the acoustical treatment measured in the field confirmed the trends of the scale-model laboratory measurements.

THE RESEARCH ON THE EFFECTIVENESS OF THE INCLINED TOP TYPE OF A NOISE BARRIER / TRIUKŠMO SLOPINIMO SIENELĖS VIRŠUTINĖS DALIES POLINKIO EFEKTYVUMO TYRIMAI

2012 ◽  
Vol 20 (2) ◽  
pp. 155-162 ◽  
Author(s):  
Žilvinas Venckus ◽  
Raimondas Grubliauskas ◽  
Albertas Venslovas
Keyword(s):  
Noise Suppression ◽  
Slope Angle ◽  
Low Frequency ◽  
Sound Waves ◽  
Noise Barriers ◽  
Frequency Sound ◽  
Effective Form ◽  
Noise Barrier ◽  
The Impact

Now, it is normally agreed that noise barriers – shields with appropriate devices on the top edge – limit the diffraction of sound waves more effectively than the usual shields of the equal or in some cases even greater height. These barriers are referred to as “edge-modified” noise shields. The article describes acoustic field researches that estimate the impact of the slope of the upper edge of the noise barrier on the effectiveness of shielding from environmental noise. The article was drafted on the basis of methodical recommendations presented in the standard ISO 11821: 1997 “Acoustics – Measurement of the in situ sound attenuation of a removable screen”. While altering the slope angle, respectively to 90°, 120°, 150°, 180°, different noise barriers were formed: “L90” (slope angle 90°), “J120”, “J150” (slope angles 120° and 150°), and the usual “straight type” (slope angle 180°). The impact made by the form of the noise barrier on the spread of noise in the noise suppression area was observed at the areas of low (100–315 Hz) and high (2000–5000 Hz) frequency. The most effective form of a barrier in reducing the diffraction of low frequency sound waves was “J120”, whereas high frequency sound waves were most effectively reduced using a usual straight noise barrier. Santrauka Paprastai pripažįstama, kad triukšmo slopinimo sienelės-ekranai su atitinkamais įtaisais ant jų viršutinio krašto efektyviau riboja garso bangų difrakciją, palyginti su įprastiniais tokio pat aukščio, o kai kuriais atvejais ir aukštesniais, ekranais. Ekranai su įtaisais vadinami „modifikuotosios briaunos“ triukšmo slopinimo ekranais. Atliekant akustinius natūrinius tyrimus vertinta triukšmo slopinimo sienelės viršutinės dalies polinkio įtaka aplinkoje sklindančio garso bangų ekranavimo efektui. Tyrimų metodika parengta pagal EN ISO 11821:1997 „Akustika. Natūrinis kilnojamo ekrano garso silpninimo matavimas“ standarte pateikiamas metodines rekomendacijas. Polinkio kampą keičiant atitinkamai 90°, 120°, 150°, 180°, formuota „L90“ (polinkio kampas 90°), „J120“, „J150“ (polinkio kampas 120° ir 150°) ir įprastinio „tiesiojo tipo“ (polinkio kampas 180°) triukšmo slopinimo sienelės. Triukšmo slopinimo sienelės formos įtaka triukšmo sklaidai stebima žemojo (100–315 Hz) ir aukštojo dažnio (2000–5000 Hz) srityse. Žemojo dažnio garso bangų difrakciją efektyviausiai sumažina „J120“ formos ekranas, aukštojo dažnio srityje didžiausias ekranavimo efektas pasiektas taikant įprastinę „tiesiojo tipo“ triukšmo slopinimo sienelę.

Heat Treatment Influence on the Corrosion Resistance of a Cu-Al-Fe-Mn Bronze

2018 ◽  
Vol 69 (5) ◽  
pp. 1055-1059 ◽  
Author(s):  
Mariana Ciurdas ◽  
Ioana Arina Gherghescu ◽  
Sorin Ciuca ◽  
Alina Daniela Necsulescu ◽  
Cosmin Cotrut ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Corrosion Resistance ◽  
Structural Changes ◽  
Heating Temperature ◽  
Galvanic Corrosion ◽  
Cooling Water ◽  
Open Circuit ◽  
Water Quenching ◽  
Heat Treated ◽  
Different Temperatures

Aluminium bronzes are exhibiting good corrosion resistance in saline environments combined with high mechanical properties. Their corrosion resistance is obviously confered by the alloy chemical composition, but it can also be improved by heat treatment structural changes. In the present paper, five Cu-Al-Fe-Mn bronze samples were subjected to annealing heat treatments with furnace cooling, water quenching and water quenching followed by tempering at three different temperatures: 200, 400 and 550�C. The heating temperature on annealing and quenching was 900�C. The structure of the heat treated samples was studied by optical and scanning electron microscopy. Subsequently, the five samples were submitted to corrosion tests. The best resistance to galvanic corrosion was showed by the quenched sample, but it can be said that all samples are characterized by close values of open-circuit potentials and corrosion potentials. Concerning the susceptibility to other types of corrosion (selective leaching, pitting, crevice corrosion), the best corrosion resistant structure consists of a solid solution, g2 and k compounds, corresponding to the quenched and 550�C tempered sample.

scholarly journals The optimum orientation of an absorbing barrier

2005 ◽  
Vol 461 (2060) ◽  
pp. 2369-2383 ◽  
Author(s):  
A.D Rawlins
Keyword(s):  
Noise Level ◽  
Noise Source ◽  
Shadow Region ◽  
Source Position ◽  
Absorbent Material ◽  
Noise Barrier ◽  
Receiver Point

In the following work, we solve the problem of the best orientation of a rigid noise barrier, which has one face lined with absorbent material, between a noise source and a receiver point in the shadow region of the barrier. By the ‘best orientation’, we mean that positioning of the barrier which yields the least noise level at the receiving point for a given barrier and source position.

Perception of Traffic Noise Barrier Effectiveness: Public Opinion Survey of Residents Living near I-71

1997 ◽  
Vol 1601 (1) ◽  
pp. 49-54 ◽  
Author(s):  
Lloyd A. Herman ◽  
Michael A. Finney ◽  
Craig M. Clum ◽  
E.W. Pinckney
Keyword(s):  
Public Opinion ◽  
Traffic Noise ◽  
Department Of Transportation ◽  
Opinion Survey ◽  
Noise Barriers ◽  
Noise Abatement ◽  
Public Controversy ◽  
Public Opinion Survey ◽  
Project Area ◽  
Noise Barrier

The completion of the largest Ohio Department of Transportation traffic noise abatement project in 1995 was met with public controversy over the effectiveness of the noise barriers. A public opinion survey was designed to obtain the perceptions of the residents in the project area. In a departure from most surveys of traffic noise barrier effectiveness, the coverage was not limited to the first or second row of houses, but was extended to 800 m on each side of the roadway. It was found that the larger survey area was needed to avoid misleading conclusions. Overall perceptions of noise barrier effectiveness were found to vary with distance from the roadway and with noise barrier configuration.

Effects of Railway Noise on Residents’ in A Residential Area

2021 ◽  
Vol 3 (01) ◽  
pp. 17-28
Author(s):  
Ria Anggreani Syahputri ◽  
Budi Damianto
Keyword(s):  
Noise Level ◽  
Sleep Disturbances ◽  
Sampling Technique ◽  
Residential Area ◽  
Comfort Level ◽  
Simple Method ◽  
Urban Village ◽  
Noise Measurements ◽  
Influence Of Noise

Population growth in Depok City is large and not in accordance with development land causes many residents’ to build houses with conditions <5 meters from the line of Electric Rail Train or Kereta Rel Listrik (KRL); this causes changes in the quality of the environment, including noise. The objective of this study is to determine the noise level, and the results will be compared with the standard noise level of the residential area; also, to find the influence of noise on residents’. This research was conducted in the area of ​​Rawa Geni Raya Street, 1st Neighborhood, Ratu Jaya Urban Village, Depok City. Noise measurements were carried out at 5-points using a simple method with a noise level measuring instrument (SLM). At one time, the measurement was taken for 10 minutes with a reading time of every 5 seconds. The questionnaire was measured using a Purposive Random Sampling technique, and the number of samples was calculated using the Slovin formula. The results of this study indicate that the 5-point noise level exceeds the recommended threshold according to KEPMEN LH 48 of 1996 and PERMENKES 718/1987 at  55 dB(A). The largest value for the 24-hour noise level (LSM) is at point 1, which is 5 m from the KRL line. The noise level on the weekday is 75.32 dB(A) and 74.24 dB(A) on weekends. According to PERMENKES No 718/1987, the location of point 1 should be included in Area D as an industrial zone, plant, railway station, and bus terminal. The results of questionnaires by 34 respondents showed that the noise generated by KRL was noisy and the majority of respondents agreed the noise affected the comfort level; in terms of health, respondents agreed KRL noise caused sleep disturbances and hearing loss.

scholarly journals Spiral Sound Wave Transducer Based on the Longitudinal Vibration

Sensors ◽  
2018 ◽  
Vol 18 (11) ◽  
pp. 3674 ◽  
Author(s):  
Wei Lu ◽  
Yu Lan ◽  
Rongzhen Guo ◽  
Qicheng Zhang ◽  
Shichang Li ◽  
...  
Keyword(s):  
Sound Wave ◽  
Longitudinal Vibration ◽  
Three Dimensional ◽  
Low Frequency ◽  
Sound Field ◽  
Field Measurements ◽  
Sound Waves ◽  
Underwater Sound ◽  
Three Dimensional Finite Element ◽  
Wave Transducer

A spiral sound wave transducer comprised of longitudinal vibrating elements has been proposed. This transducer was made from eight uniform radial distributed longitudinal vibrating elements, which could effectively generate low frequency underwater acoustic spiral waves. We discuss the production theory of spiral sound waves, which could be synthesized by two orthogonal acoustic dipoles with a phase difference of 90 degrees. The excitation voltage distribution of the transducer for emitting a spiral sound wave and the measurement method for the transducer is given. Three-dimensional finite element modeling (FEM)of the transducer was established for simulating the vibration modes and the acoustic characteristics of the transducers. Further, we fabricated a spiral sound wave transducer based on our design and simulations. It was found that the resonance frequency of the transducer was 10.8 kHz and that the transmitting voltage resonance was 140.5 dB. The underwater sound field measurements demonstrate that our designed transducer based on the longitudinal elements could successfully generate spiral sound waves.

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