Applications of noise barriers with a slanted flat-tip jagged cantilever for noise attenuation on a construction site

2017 ◽  
Vol 24 (22) ◽  
pp. 5225-5232 ◽  
Author(s):  
Wang Zhaomeng ◽  
Lim Kian Meng ◽  
Prachee Priyadarshinee ◽  
Lee Heow Pueh
Keyword(s):  
Noise Pollution ◽  
Comfort Level ◽  
Destructive Interference ◽  
Noise Attenuation ◽  
Construction Site ◽  
Cross Sectional ◽  
Sound Fields ◽  
Noise Barrier ◽  
Sectional Profile ◽  
Level Of Living

Construction noise is one of the main sources of noise pollution in many cities, and degrades the comfort level of living spaces. It was previously reported that a noise barrier with a wide “cross-sectional profile” (e.g., T- or Y-shaped) could enhance the noise attenuation performance, and the jagged edge “longitudinal profile” on the top edge of the noise barrier could generate destructive interference sound fields behind the noise barrier, which could further reduce the noise levels. The present paper attempts to study the noise attenuation performances of jagged edge profiles applied on the edge of a cantilever, which was mounted at the top of a commercial passive noise barrier. In addition to the numerical simulations, the full-sized prototypes were also experimentally tested on a construction site with noise generated by a boring machine. Both numerical simulation and experimental results showed that this barrier with slanted flat-tip jagged cantilever would perform better than the traditional barrier having a Straight edge cantilever of same height, with a maximum additional attenuation of 5.0 dBA obtained experimentally. The barrier with a slanted flat-tip jagged cantilever could also extend the shadow zone behind the barrier to higher levels.

scholarly journals Noise Reduction Using Concrete Barriers: A Case Study

2021 ◽  
Vol 1197 (1) ◽  
pp. 012010
Author(s):  
A. K. Dasarathy ◽  
M. Tamil selvi
Keyword(s):  
Noise Reduction ◽  
Noise Pollution ◽  
Noise Attenuation ◽  
Noise Barriers ◽  
Innovative Design ◽  
Attenuation Effect ◽  
Traffic Conditions ◽  
Sound Barriers ◽  
Noise Barrier

Abstract Noise pollution is becoming more and more acute, and hence many researchers are studying the noise attenuation effect and prevention of noise. In this study an attempt has been made to find the reduction in noise levels at National Highway 45 near peerkankaranai in Chennai. Two sensitive places were selected along NH 45 by examining attenuation of noise by providing noise barriers in the form of concrete structures. The primary goal of this project was to identify innovative design of noise barrier that has the potential to be implemented in NH 45, Chennai. Based on the research and evaluation conducted for this study, it was recommended that two innovative barrier designs be implemented in Chennai. First, a noise prediction is made at the specified location on the highway under certain traffic conditions in order to determine the noise level by measurement and decide on the barrier requirement. The installation of sound barriers is feasible enough to cause a significant decrease in noise pollution at the roads. Considerable noise attenuation is achieved by providing concrete noise barrier. The paper provides Leq at the time of traffic data recorded was 105.1 dBA at NH45 and 91.108 dBA at NH5 during the time of observation at installation of barrier the values are 70.09 dBA 79.11 dBA, respectively. Noise reduction is possible and noise reduction is predominantly reduced by providing barrier.

X-Ray Replication of Submicrometer Linewidth Patterns

1977 ◽  
Vol 35 ◽  
pp. 136-137
Author(s):  
Henry I. Smith ◽  
D.C. Flanders
Keyword(s):  
Electron Beam Lithography ◽  
Cross Sectional ◽  
X Ray ◽  
Electron Backscattering ◽  
Spatial Frequencies ◽  
Cross Sectional Profile ◽  
Carbon Foils ◽  
Sectional Profile ◽  
And Control ◽  
Soft Radiation

Scanning electron beam lithography has been used for a number of years to write submicrometer linewidth patterns in radiation sensitive films (resist films) on substrates. On semi-infinite substrates, electron backscattering severely limits the exposure latitude and control of cross-sectional profile for patterns having fundamental spatial frequencies below about 4000 Å(l),Recently, STEM'S have been used to write patterns with linewidths below 100 Å. To avoid the detrimental effects of electron backscattering however, the substrates had to be carbon foils about 100 Å thick (2,3). X-ray lithography using the very soft radiation in the range 10 - 50 Å avoids the problem of backscattering and thus permits one to replicate on semi-infinite substrates patterns with linewidths of the order of 1000 Å and less, and in addition provides means for controlling cross-sectional profiles. X-radiation in the range 4-10 Å on the other hand is appropriate for replicating patterns in the linewidth range above about 3000 Å, and thus is most appropriate for microelectronic applications (4 - 6).

Pengaruh bising lalu lintas terhadap penurunan fungsi pendengaran pada juru parkir di kota Denpasar

2013 ◽  
Vol 40 (2) ◽  
Author(s):  
Ni Ketut Susilawati ◽  
Wayan Sudana ◽  
Eka Putra Setiawan
Keyword(s):  
Hearing Impairment ◽  
Noise Exposure ◽  
Traffic Noise ◽  
Hearing Threshold ◽  
Noise Pollution ◽  
Simple Random Sampling ◽  
Cross Sectional Study ◽  
Control Group ◽  
Cross Sectional ◽  
Hearing Function

Background: Noise pollution or noise is an unwanted sound which is disturbing to human beings.However small or soft the sound, if it is undesirable it is considered as noise. Noise induced hearingloss is a sensorineural hearing loss that is commonly encountered second to presbycusis. Purpose: Toknow the effect of traffic noise exposure on hearing impairment to the employees of the Parking DistrictCompany of the Denpasar city and to improve diagnostic detection on hearing impairment caused bynoise. Method: A cross sectional study was conducted at the Parking District Company office. Thepopulations of this study were the employees of the Parking District Company. Samples of this study were the employees who were exposed to traffic noise and control samples were an employee who was unexposed. Samples were selected by simple random sampling. Results: From 40 parking attendants,27 persons (67.5%) aged above 35 years old. The parking attendants who had been working for ten to fifteen years were 36 persons (90%) and no history using ear protection when working. Seven persons(17.5%) had referred DPOAE upon examination with increase hearing threshold on audiogram result.In this study the parking attendants who had hearing deficit induced by noise were 7 persons (17.5%)and only one person (2.5%) in control group. There was a statistically significant effect of traffic noiseto hearing function deficit (p<0.05). Conclusion: Traffic noise has effect in hearing function deficit onthe parking attendants.ORLI Vol. 40 No. 2 Tahun 2010Key words: NIHL, parking attendant, audiometry, DPOAE.

scholarly journals Bonding widths of Deposited Polymer Strands in Additive Manufacturing

Materials ◽  
2021 ◽  
Vol 14 (4) ◽  
pp. 871
Author(s):  
Cheng Luo ◽  
Manjarik Mrinal ◽  
Xiang Wang ◽  
Ye Hong
Keyword(s):  
Polymer Melt ◽  
Acrylonitrile Butadiene Styrene ◽  
High Viscosity ◽  
Numerical Results ◽  
Fused Filament Fabrication ◽  
Cross Sectional ◽  
Nozzle Height ◽  
Special Cases ◽  
Cross Sectional Profile ◽  
Sectional Profile

In this study, we explore the deformation of a polymer extrudate upon the deposition on a build platform, to determine the bonding widths between stacked strands in fused-filament fabrication. The considered polymer melt has an extremely high viscosity, which dominates in its deformation. Mainly considering the viscous effect, we derive analytical expressions of the flat width, compressed depth, bonding width and cross-sectional profile of the filament in four special cases, which have different combinations of extrusion speed, print speed and nozzle height. We further validate the derived relations, using our experimental results on acrylonitrile butadiene styrene (ABS), as well as existing experimental and numerical results on ABS and polylactic acid (PLA). Compared with existing theoretical and numerical results, our derived analytic relations are simple, which need less calculations. They can be used to quickly predict the geometries of the deposited strands, including the bonding widths.

Measurement of cross-sectional profile for sub-15nm hp LS patterns in nanoimprint templates using small-angle x-ray scattering

2020 ◽  
Author(s):  
Kazuki Hagihara ◽  
Eiji Yamanaka ◽  
Yoshiyasu Ito ◽  
Kiyoshi Ogata ◽  
Kazuhiko Omote ◽  
...  
Keyword(s):  
Small Angle ◽  
Cross Sectional ◽  
X Ray ◽  
X Ray Scattering ◽  
Cross Sectional Profile ◽  
Sectional Profile ◽  
Ray Scattering

Torsional Stiffness of a Thin-Walled Beam Braced by Pinned or Rigidly Fixed Transverse Diaphragms

1973 ◽  
Vol 15 (5) ◽  
pp. 351-356
Author(s):  
T. Harrison ◽  
J. M. Siddall
Keyword(s):  
Experimental Evidence ◽  
Theoretical Work ◽  
Torsional Stiffness ◽  
Cross Sectional ◽  
Cross Sectional Profile ◽  
Thin Walled ◽  
Sectional Profile ◽  
Good Agreement

The torsional stiffness of a thin-walled beam of open cross-sectional profile braced by evenly spaced transverse diaphragms is studied. Diaphragms rigidly fixed or attached by frictionless pins are treated and it is seen that, in either case, the only effect is to modify the St Venant torsional constant for the thin-walled beam. The theoretical work is supported by experimental evidence from two braced perspex channels which simulate the two assumed methods of attaching the diaphragms. Good agreement is demonstrated.

scholarly journals Influence of environmental factors and its associated health risks of noise pollution in Owerri Metropolis, Imo State, Nigeria

2021 ◽  
Vol 8 (1) ◽  
pp. 001-010
Author(s):  
Mbaegbu Nnamdi O ◽  
Oparaocha Evangeline T ◽  
Ede Alison O ◽  
Zubair Abdulkarim I ◽  
Odupute Colman N ◽  
...  
Keyword(s):  
Environmental Factors ◽  
Health Risks ◽  
Noise Level ◽  
Sampling Technique ◽  
Noise Pollution ◽  
Cluster Sampling ◽  
Noise Generation ◽  
Residential Areas ◽  
Cross Sectional ◽  
Descriptive Research

Noise pollution contributes to environmental degradation and poses a threat to human and terrestrial lives. Noise pollution can be regarded as environmental noise and the propagation of noise may develop a harmful impact on the activity of human or animal life. This study was conducted to determine the influence of environmental factors and its associated health risks of noise pollution in Owerri Metropolis, Nigeria. The study employed a cross sectional descriptive research design. Measurement of noise levels was carried out at 24 different locations. The sampling technique used in this study was a cluster sampling technique. The average reading for each location and each ward were calculated. Also, 900 respondents comprising adults who live and/or operate in the areas were interviewed on the health risks associated with noise, using structured and standardized questionnaire. The results obtained showed that the computed average noise level at the 24 different locations ranged from 79.4 – 95.8dB, and all of which were significantly (P<0.05) above the acceptable standard ranges of <80dB, thereby rating the noise level not acceptable because they can be capable of causing discomfort and pains in man. Influence of environmental factors on noise pollution; 29(3.2%) reported heavy vehicular traffic plying residential areas contributed to noise generation, 33(3.7%) said indiscriminate blowing of siren. Perceived health risks were reported as 47(5.2%) disturbs sleep, 24(2.7%) causes annoyance, 41(4.61%) causes headache and 21(2.3%) interference with conversation. In conclusion, environmental factors, poor education and lack of enforcement of the laws influence noise generation and there is need to check the level of noise pollution in Owerri Metropolis.

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 Study of general health among older adult in ardakan city and its relation with traffic noise pollution at the residence Summary

2021 ◽  
Author(s):  
Ehsan Janati ◽  
Mohammad Ali Morowati Sharifabad ◽  
Reza Jafari Noudushan ◽  
Mohamad Javad Zare Sakhvidi ◽  
Sara Jambarsang
Keyword(s):  
Sleep Disorders ◽  
Significant Relationship ◽  
General Health ◽  
Traffic Noise ◽  
General Health Questionnaire ◽  
Noise Pollution ◽  
The Elderly ◽  
The Body ◽  
Cross Sectional ◽  
Pollution Levels

Introduction: The body's response to noise pollution is very similar to the way the body responds to stress, which can lead to poor health over time. In this regard, this study was conducted to determine the general health of the elderly and its relationship with traffic noise pollution in Ardakan. Methods: This descriptive cross-sectional study was conducted in 1399. Participants were 200 elderly people in Ardakan and were included in the study by random sampling. Data were collected through sound measurement with SVANTEK device, General Health Questionnaire 28 (GHQ-28). After completing the questionnaires and measurements, the collected data were entered into SPSS-19 software and descriptive statistics as well as analytical statistics including: Chi-square, regression and analysis of variance were used to analyze it. Results: The overall average sound level equivalent in decibels at all measuring stations was within the standard range. There was a significant relationship between noise annoyance and the dimensions of "anxiety symptoms and sleep disorders" and "depressive symptoms" of general health (p <0.001). Conclusion: People with more voice annoyance have more anxiety, sleep disorders and depression. Existence of noise pollution levels in the allowable or standard level can lead to the observation of no significant relationship between traffic noise pollution levels and general health. Reducing anxiety, depression and sleep disorders in the elderly is possible with interventions to reduce voice irritation in them.  

scholarly journals Influence of Geometric Parameters on Aerodynamic and Acoustic Performances of Bladeless Fans

2019 ◽  
Author(s):  
Ang Li ◽  
Jun Chen ◽  
Yangfan Liu ◽  
Stuart Bolton ◽  
Patricia Davies
Keyword(s):  
Cross Section ◽  
Fluid Dynamic ◽  
Geometric Parameters ◽  
Design Stage ◽  
Air Velocity ◽  
Cross Sectional ◽  
Future Design ◽  
Cross Sectional Profile ◽  
The Cross ◽  
Sectional Profile

Abstract In recent years, the bladeless fan that does not have visible impellers have been widely applied in household appliances. Since the customers are particularly sensitive to noise and the strength of wind generated by the fan, the aerodynamic and acoustic performances of the fan need to be accurately characterized in the design stage. In this study, computational fluid dynamic (CFD) and computational aeroacoustics (CAA) are applied to investigate the performances of different designs of a bladeless fan model. The influence of four parameters, namely the airfoil selection for cross-section of the wind channel, the slit width, the height of cross-section and the location of the slit, is investigated. The results indicate the streamwise air velocity increases significantly by narrowing the outlet, but the noise level increases simultaneously. In addition, the generated noise increases while the height of fan cross-section increases, and a 4mm height of the cross section is optimal for aerodynamic performance. When the slit is closer to the location of maximum thickness, the performances of the bladeless fan increases. Moreover, the performance is not changed significantly by changing the cross-sectional profile. Finally, the optimal geometric parameters are identified to guide the future design of the bladeless fan.

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