Optimized T-Shape and Y-Shape Inclined Sound Barriers for Railway Noise Mitigation

Noise Notes ◽  
2014 ◽  
Vol 13 (3) ◽  
pp. 159-172
Author(s):  
Mostafa Karimi ◽  
Davood Younesian
Keyword(s):  
Noise Mitigation ◽  
Railway Noise ◽  
Sound Barriers

Study and Design Comprehensive Denoise System for Railway

2013 ◽  
Vol 448-453 ◽  
pp. 306-312
Author(s):  
Ying Zhou ◽  
Wen Jing Gu ◽  
Dan Wei Huang ◽  
Xi Zhong Wang ◽  
Zi Chi Liu ◽  
...  
Keyword(s):  
National Standard ◽  
Functional Area ◽  
Night Time ◽  
Acoustic Environment ◽  
Railway Line ◽  
Railway Noise ◽  
Sound Barriers ◽  
Modeling Theory ◽  
First Time ◽  
Better Than

The modeling theory to railway noise is applied and made a noise reduction system for the first time in this paper. Through test and analysis, the sound barriers and train skirts with better performance were selected to form a comprehensive denoise system. The performance of T-type sound barriers works better than straight-type; with the comprehensive denoise system, the railway noise in the simulative boundary alongside railway line and acoustic environment functional area II decrease by 9.24 dB(A) and 8.40 dB(A), respectively. In terms of energy, sound energy decline to 11.8% and 14.4%, separately; after installing the comprehensive denoise system, the day-time noise of all the points in acoustic environment functional area II reach the limits; as to the night-time noise, 75% points reach the national standard limits.

Pavement noise investigation on North Carolina highways: an on-board sound intensity approach

2012 ◽  
Vol 39 (8) ◽  
pp. 878-886 ◽  
Author(s):  
George Wang ◽  
Gregory Smith ◽  
Richard Shores
Keyword(s):  
North Carolina ◽  
Traffic Noise ◽  
Sound Intensity ◽  
Surface Friction ◽  
Future Research ◽  
Noise Levels ◽  
Noise Mitigation ◽  
Different Types ◽  
Sound Barriers ◽  
Pavement Noise

This paper presents the findings on tire–pavement noise on various types of pavements by using an on-board sound intensity (OBSI) method. Mitigation of traffic noise has become an increasingly important consideration for highway agencies when constructing new highways or improving the existing systems. As a competitive alternative for noise mitigation, quieter pavement may provide advantages that noise barriers do not have, or to where sound barriers are not suited. The first step in developing quieter pavement is identifying the noise levels of different types of highway pavements. To reach the ultimate goals of quieter pavement development, this research has focused on the most imperative task, i.e., to measure the noise levels of different types of pavements in North Carolina (NC). Pavement noise levels of 61 highway sites including 153 test sections around 30 counties for nine types of pavements across North Carolina have been investigated. A thorough literature review was conducted and OBSI testing equipment with sound intensity measuring process was established during this study. The results of OBSI data indicate that the tire–pavement noise levels of the six dense graded surface courses in NC are in a lower range, from 98.2 to 99.6 dBA, comparing with other dense graded surface friction courses in other states. The overall findings indicate that relatively quieter pavements have been used in North Carolina. The OBSI data collected will provide valuable information in future research for quieter pavement development and traffic noise management.

Case study: Prediction and field tests of railway noise and effects of a low-height noise barrier

2020 ◽  
Vol 68 (4) ◽  
pp. 303-314
Author(s):  
Yuna Park ◽  
Hyo-In Koh ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
University of Science and Technology, Transpo ◽  
...  
Keyword(s):  
High Speed ◽  
Field Tests ◽  
Residential Areas ◽  
Railway Systems ◽  
Railway Noise ◽  
Sound Levels ◽  
Noise Barrier ◽  
The Difference ◽  
Reduction Effect ◽  
The Impact

Railway noise is calculated to predict the impact of new or reconstructed railway tracks on nearby residential areas. The results are used to prepare adequate counter- measures, and the calculation results are directly related to the cost of the action plans. The calculated values were used to produce noise maps for each area of inter- est. The Schall 03 2012 is one of the most frequently used methods for the production of noise maps. The latest version was released in 2012 and uses various input para- meters associated with the latest rail vehicles and track systems in Germany. This version has not been sufficiently used in South Korea, and there is a lack of standard guidelines and a precise manual for Korean railway systems. Thus, it is not clear what input parameters will match specific local cases. This study investigates the modeling procedure for Korean railway systems and the differences between calcu- lated railway sound levels and measured values obtained using the Schall 03 2012 model. Depending on the location of sound receivers, the difference between the cal- culated and measured values was within approximately 4 dB for various train types. In the case of high-speed trains, the value was approximately 7 dB. A noise-reducing measure was also modeled. The noise reduction effect of a low-height noise barrier system was predicted and evaluated for operating railway sites within the frame- work of a national research project in Korea. The comparison of calculated and measured values showed differences within 2.5 dB.

scholarly journals Artificial Neural Network Assisted Error Correction for MLC NAND Flash Memory

Micromachines ◽  
2021 ◽  
Vol 12 (8) ◽  
pp. 879
Author(s):  
Ruiquan He ◽  
Haihua Hu ◽  
Chunru Xiong ◽  
Guojun Han
Keyword(s):  
Neural Network ◽  
Error Correction ◽  
Error Detection ◽  
Flash Memory ◽  
Nand Flash ◽  
Data Reliability ◽  
Nand Flash Memory ◽  
Process Technology ◽  
Noise Mitigation ◽  
Memory Channel

The multilevel per cell technology and continued scaling down process technology significantly improves the storage density of NAND flash memory but also brings about a challenge in that data reliability degrades due to the serious noise. To ensure the data reliability, many noise mitigation technologies have been proposed. However, they only mitigate one of the noises of the NAND flash memory channel. In this paper, we consider all the main noises and present a novel neural network-assisted error correction (ANNAEC) scheme to increase the reliability of multi-level cell (MLC) NAND flash memory. To avoid using retention time as an input parameter of the neural network, we propose a relative log-likelihood ratio (LLR) to estimate the actual LLR. Then, we transform the bit detection into a clustering problem and propose to employ a neural network to learn the error characteristics of the NAND flash memory channel. Therefore, the trained neural network has optimized performances of bit error detection. Simulation results show that our proposed scheme can significantly improve the performance of the bit error detection and increase the endurance of NAND flash memory.

scholarly journals Comparison of Annoyance from Railway Noise and Railway Vibration

2017 ◽  
Vol 14 (7) ◽  
pp. 805 ◽  
Author(s):  
Mikael Ögren ◽  
Anita Gidlöf-Gunnarsson ◽  
Michael Smith ◽  
Sara Gustavsson ◽  
Kerstin Persson Waye
Keyword(s):  
Railway Noise

Acoustic meta-silencer: Toward enabling ultrawide-band air-permeable noise barrier

2021 ◽  
pp. 107754632110011
Author(s):  
Mohammad Javad Khodaei ◽  
Amin Mehrvarz ◽  
Reza Ghaffarivardavagh ◽  
Nader Jalili
Keyword(s):  
Heat Transfer ◽  
Design Methodology ◽  
Heat Transfer Performance ◽  
Transmission Loss ◽  
Design Parameters ◽  
Transfer Performance ◽  
Noise Mitigation ◽  
Acoustic Cavity ◽  
Road Map ◽  
Noise Barrier

In this article, we have first presented a metasurface design methodology by coupling the acoustic cavity to the coiled channel. The geometrical design parameters in this structure are subsequently studied both analytically and numerically to identify a road map for silencer design. Next, upon tuning the design parameters, we have introduced an air-permeable noise barrier capable of sound silencing in the ultrawide band of the frequency. It is has been shown that the presented metasurface can achieve +10 dB sound transmission loss from 170 Hz to 1330 Hz (≈3 octaves). Furthermore, we have numerically studied the ventilation and heat transfer performance of the designed metasurface. Enabling noise mitigation by leveraging the proposed metasurface opens up new possibilities ranging from residential and office noise reduction to enabling ultralow noise fan, propellers, and machinery.

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