Low-noise Thin Surface Course – Evaluation of the Effectiveness of Noise Reduction

2021 ◽

Vol 263 (4) ◽

pp. 2930-2939

Author(s):

Byungchae Kim ◽

Hyunjin Kim ◽

Wonuk Kang

Keyword(s):

Noise Reduction ◽

Noise Level ◽

Measurement Method ◽

Road Traffic ◽

Low Noise ◽

Management Standards ◽

Close Proximity ◽

Porous Pavement ◽

Reduction Effect ◽

Measurement Location

In Korea, road noise is assessed as a measurement method of exterior noise emitted by road vehicle for management standards by the National Institute of Environmental Sciences. In this method, the noise felt at the actual pickup point is measured as LAeq (the roadside equivalent noise level). Recently, to clarify the standard for measuring noise on low-noise pavements, the CPX (ISO11819-2; Close-proximity method) was first introduced in the Porous Pavement Guidelines of the Ministry of Land, Infrastructure and Transport. According to ISO, the CPX adopts the side microphone as a mandatory measurement location, and the rear optional. The side location has been a mandatory due to its high correlation with SPB (ISO 11819-1, Statistical Pass-by method). However, according to our previous study on the correlation evaluation between L and CPX rear microphone noise level, both noise reduction effect was about 9-12 dB(A) showed a high correlation in Korea where heavy road traffic is common. The following study aims to show the consistent correlation between the L and CPX rear noise level. Furthermore, it is intended to be helpful in selecting the location of the CPX microphone that can most effectively represent the actual noise on the low-noise pavement in Korea.

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A design of ultra-low noise LDO using noise reduction network techniques

2017 International SoC Design Conference (ISOCC) ◽

10.1109/isocc.2017.8368850 ◽

2017 ◽

Author(s):

Hamed Abbasizadeh ◽

Behnam Samadpoor Rikan ◽

Truong Thi Kim Nga ◽

Kwan-Tae Kim ◽

SungJin Kim ◽

...

Keyword(s):

Noise Reduction ◽

Low Noise ◽

Ultra Low Noise

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Additional noise reduction with diffracting elements on barriers: experimental testing

INTER-NOISE and NOISE-CON Congress and Conference Proceedings ◽

10.3397/in-2021-2194 ◽

2021 ◽

Vol 263 (4) ◽

pp. 2654-2664

Author(s):

Wout Schwanen ◽

Mark Mertens ◽

Ysbrand Wijnant ◽

Willem Jan van Vliet

Keyword(s):

Noise Reduction ◽

Experimental Testing ◽

Low Noise ◽

Motor Vehicles ◽

Additional Element ◽

High Noise ◽

Quarter Wavelength ◽

Noise Barrier ◽

Sound Reduction ◽

Development And Validation

The noise reduction of a (low) noise barrier can be enhanced by using an additional element with quarter-wavelength resonators with varying depths. The so-called WHISwall or WHIStop deflects sound upwards for specific frequencies creating an additional sound reduction. Different experiments on the WHISwall and WHIStop are performed as input for model validation. The development and validation of the model are described in a separate paper. In this paper the measurement campaign and its results are presented. We performed measurements on two setups. The first setup consists of a 1.1 meter high WHISwall, a 1.1m high noise barrier and a reference section (without noise measure). Measurements have been conducted with both an artificial sound source and pass by measurements with light and heavy motor vehicles. In a second test setup, the WHIStop was placed on top of a 4 meter high noise barrier and the diffraction was determined according the European standard EN 1793-4.

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Development and Application of a Multi-Disciplinary Multi-Regime Design Methodology of a Low-Noise Contra-Rotating Open-Rotor

Volume 2C: Turbomachinery ◽

10.1115/gt2015-43432 ◽

2015 ◽

Cited By ~ 1

Author(s):

Michaël Leborgne ◽

Timothée Lonfils ◽

Ingrid Lepot

Keyword(s):

Noise Reduction ◽

High Speed ◽

Design Methodology ◽

Design Procedure ◽

Low Noise ◽

Design Parameters ◽

Mechanical Constraints ◽

Open Rotor ◽

Mechanical Optimization ◽

Lifting Line

This paper focuses on the development and exploitation of a multi-disciplinary, optimization-assisted, design methodology for contra-rotating open-rotors. The design procedure relies on a two-step approach. An aero-mechanical optimization is first performed to generate a geometry with good performances over several high-speed points representative of a mission. This geometry is subsequently used as the baseline of an aero-mechanical-acoustic optimization focusing on interaction noise reduction at Cutback and Sideline low-speed points. In terms of design parameters, both rotors are modified for the first phase but only the upper part of the front rotor is altered for the noise minimization. A fully-automatic high-fidelity aero-mechanical-acoustic computational chain with fluid-structure coupling is exploited in combination with evolutionary algorithms assisted by surrogate models for the constrained-optimization process. The acoustic footprint is estimated by a simplified but fast and relevant formulation combining an unsteady lifting-line and an acoustic propagation method. The best geometry of the first design gains 1.2pt in weighted efficiency while respecting all the aero-mechanical constraints. The acoustic optimization shows that noise reduction at Sideline and Cutback points is strongly antagonistic. However, significant Sideline noise reduction from 3.5 to 5.5dB depending on the harmonics is achieved while maintaining Cutback noise and without major degradation of high-speed efficiency.

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Optimized Asphalt Mixtures for Noise Reduction in Lithuanian Roads

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.614.618 ◽

2014 ◽

Vol 614 ◽

pp. 618-621

Author(s):

Audrius Vaitkus ◽

Tadas Andriejauskas ◽

Laura Čygaitė ◽

Jurgita Židanavičiūtė

Keyword(s):

Noise Reduction ◽

Noise Pollution ◽

Low Noise ◽

Asphalt Pavements ◽

Noise Levels ◽

Road Noise ◽

Negative Effects ◽

Development Experience ◽

Growing Economy ◽

Generation Mechanisms

In the world of growing economy and population, the need of transportation is rapidly increasing also raising problems of noise pollution. Environmental noise levels are increasing in parallel with increasing traffic flows resulting negative effects for society, wildlife and economy. The article gives an overview about the main transport noise source tyre/road noise, its generation mechanisms and influencing factors. One of the most effective and promising tyre/road noise solutions is low noise pavements, which has different noise reduction approaches. Low noise asphalt pavements and theoretical noise reduction principles are analysed in the paper as well as the development experience of particular low noise asphalt pavements for Lithuanian conditions.

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Noise Reduction Technique for Digital Image Based Full Field Strain Measurement

Volume 2: 32nd Computers and Information in Engineering Conference, Parts A and B ◽

10.1115/detc2012-70704 ◽

2012 ◽

Cited By ~ 2

Author(s):

Yoshitaka Wada ◽

Tomonari Furukawa

Keyword(s):

Noise Reduction ◽

Digital Image ◽

Strain Measurement ◽

Low Noise ◽

Reduction Technique ◽

Distortion Correction ◽

Image Correlation ◽

Full Field ◽

Deformation Problem ◽

Noise Reduction Technique

In recent years several techniques of full-field measurement have been studied by digital image correlation method, moiré interference method and holographic interferometry method and so on. Image based method can be easily applied to large deformation problem and moving specimen at slow speed. Because digital camera capabilities, which are high resolution, low noise and faster data transfer speed, have been improved, very small strain measurement can be achieved by those improvements. The improvement will widen those applications, for example, moving object at high speed and less 0.1% strain measurement which is almost the same accuracy with a precise strain gauge. In order to apply the advanced application, noise reduction for a digital image and lens distortion correction for an optical system should be developed. In this paper we propose noise reduction technique using statistical camera model to be applied to any kinds of digital cameras.

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Design, Dynamics and Active Control of Micro Interferometers for Low Noise Parallel Operation

Volume 13: Nano-Manufacturing Technology; and Micro and Nano Systems, Parts A and B ◽

10.1115/imece2008-69238 ◽

2008 ◽

Author(s):

Omkar Karhade ◽

Levent Degertekin ◽

Thomas Kurfess

Keyword(s):

Noise Reduction ◽

Range Of Motion ◽

Active Control ◽

Control Algorithm ◽

Cutoff Frequency ◽

Low Noise ◽

Experimental Results ◽

Ambient Vibration ◽

Limited Range Of Motion ◽

Tunable Gratings

Micromachined Scanning Grating Interferometer (μSGI) array offers a viable solution to the high resolution, large bandwidth, non-contact and high throughput metrology. Parallel active control of μSGIs is necessary to reduce the effect of positioning errors and ambient vibration noise. To achieve individual control of the μSGIs, the gratings in the μSGI are micromachined on Silicon membranes, which can be electrostatically actuated. These tunable gratings are designed to have sufficient range of motion (∼400nm) and sufficient bandwidth (∼50kHz) for effective noise reduction. The tunable gratings are fabricated successfully using Silicon on Insulator wafers with a two mask process. A novel recurrent calibration based control algorithm is designed to actively control the tunable gratings. The novel algorithm is implemented digitally using FPGA on an array of μSGIs simultaneously. The algorithm compensates for the non-linearities of the actuator and problem due to limited range of motion. A system model is built to design and analyze the control algorithm and is verified by experimental results. Experimental results show 100 times noise reduction at low frequencies and 6.5kHz noise reduction cutoff frequency. A resolution of 1×10−4 nmrms/√Hz is achieved by implementation of this algorithm on μSGI.

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Low Noise EEG Amplifier Board for Low Cost Wearable BCI Devices

International Journal of Biomedical and Clinical Engineering ◽

10.4018/ijbce.2016070102 ◽

2016 ◽

Vol 5 (2) ◽

pp. 17-28

Author(s):

Ravim ◽

Suma K. V.

Keyword(s):

Noise Reduction ◽

Digital Signal Processor ◽

Low Cost ◽

Processing System ◽

Digital Signal ◽

Low Noise ◽

Digital Data ◽

Signal Processing System ◽

Analog To Digital ◽

Reduction Techniques

Designing a real-time BCI device requires an Electroencephalogram (EEG) acquisition system and a signal processing system to process that acquired data. EEG acquisition boards available in market are expensive and they are required to be connected to computer for any processing work. Various low cost Digital Signal Processor (DSP) boards available in market come with internal Analog to Digital converters and peripheral interfaces. The idea is to design a low cost EEG amplifier board that can be used with these commercially available DSP boards. The analog data from EEG amplifier can be converted to digital data by DSP board and sent to computer via an interface for algorithm development and further control operations. EEG amplifiers are highly affected by noise from environment. Proper noise reduction techniques are implemented and simulated in circuit design. Each filter stage and noise reduction circuit is evaluated for a low noise design.

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