Simulation and Analysis of Noise Control Scheme for Hangzhou Cigarette Factory New Packing Workshop

2014 ◽  
Vol 675-677 ◽  
pp. 217-224
Author(s):  
Yan Ping Wang ◽  
Xin Zhong Li ◽  
Yue Chao Wu ◽  
Jun Hao
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Noise Control ◽  
Pressure Level ◽  
Working Environment ◽  
Analysis Method ◽  
Control Scheme ◽  
Packaging Machine ◽  
Noise Test ◽  
Machine Station

Based on the noise test data of existing workshop, the noise of new packing workshop was studied. The effection of several noise control scheme was predicted by simulation and analysis method, and the control scheme five was chose finally ,by which average noise reduction was about 4.5dB,and 8h equivalent continuous A-weighted sound pressure level of the pick-up coil station and packaging machine station was 84.9dB and 83.2dB respectively, the working environment of the new workshop was effectively improved, and the investment was estimated.

scholarly journals The exposure of working environment noise in the agricultural service workplaces

2009 ◽  
Vol 55 (No. 2) ◽  
pp. 69-75 ◽  
Author(s):  
M. Šístková ◽  
A. Peterka
Keyword(s):  
Human Health ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Pressure Level ◽  
Working Environment ◽  
Service Workers ◽  
Permissible Exposure Limit ◽  
Noise Characteristics ◽  
Exposure Limit ◽  
Environment Noise

The noise belongs to the leading harmful factors which pollute the environment and negatively influences human health. An overview measurement concerning the noise characteristics has been done in agricultural service workplaces. The sound pressure level has been measured and the length of the workers exposition has been elicited in each workplace. The obtained data has proved that some agricultural service workers have been exposed to a noise above the permissible exposure limit.

Active noise control system in a fire helmet – a proposal of the solution

2018 ◽  
Vol 558 (3) ◽  
pp. 11-15
Author(s):  
Leszek Morzyński ◽  
Grzegorz Szczepański
Keyword(s):  
Control System ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Noise Control ◽  
Active Noise Control ◽  
Warning Signal ◽  
Verbal Communication ◽  
Pressure Level ◽  
Emergency Vehicle ◽  
Active Noise

An auditory warning signal emitted by a moving emergency vehicle is intended to inform other road users about an approaching emergency vehicle and the need to give way to it. Emission of a warning signal with the highest possible sound pressure level is the main method of ensuring the audibility and recognition of the warning signal by traffic participants at unknown and varying traffic noise, acoustic insulation of vehicles and noise in the interior of the vehicle. The A-weighted sound pressure level of the auditory warning signal reaching the interior of an emergency vehicle may exceed 90 dB, which can be harmful to the hearing, can adversely affect psychophysical fitness of the crew members and can significantly hinder verbal communication in the vehicle. This article presents the concept and results of numerical simulations of an active noise control system in fire helmets, which will reduce the exposure of the crew to the warning signal and improve the quality of verbal communication in an emergency vehicle. This system is integrated with the signal generation system. The Notch algorithm and the NLMS adaptation algorithm were used in the system's control algorithm. The construction of the controller was based on a microcontroller from the STM32F4 family.

Jackhammer Chisel Noise Control

2015 ◽  
Author(s):  
Henry A. Scarton ◽  
Kyle R. Wilt
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Noise Control ◽  
Pressure Level ◽  
Longitudinal Impact ◽  
Geometric Properties ◽  
Longitudinal Modes ◽  
Transverse Bending ◽  
Severe Reduction

A robust chisel damper for quieting a jackhammer is presented. The noise produced from a jackhammer chisel is dominated by the ringing of the chisel moil resulting from impacts of the internal hammer against the end of the chisel producing airborne radiation of the transverse bending and longitudinal modes. A model steel chisel moil point was constructed with geometric properties similar to a jackhammer chisel and designed so as to not fail during severe acceleration impacts from the reciprocating hammer. Anechoic tests of the maximum overall unweighted sound pressure level for the undamped chisel due to a longitudinal impact was 86.8 dB linear (re. to 20 μ Pa) at 1 meter with the strongest ring tone at 1.37 kHz and harmonics; the overall sound pressure level for the damped chisel with identical axial impacts was reduced by 16.5 dB to 70.3 dB with severe reduction of 40 dB of the dominant chisel ring tone, and the harmonics.

The Analysis on the Effect of Ground Reflection in the Noise Test of Aircraft Engine

2013 ◽  
Vol 860-863 ◽  
pp. 2256-2260
Author(s):  
Guo Hua Yan ◽  
Shuai Chang ◽  
Yong Lei Zhang
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Free Field ◽  
Aircraft Engine ◽  
Pressure Level ◽  
Engine Noise ◽  
Certification Procedure ◽  
Noise Test ◽  
The Impact ◽  
Field Sound

The data processing of static engine noise test, especially the elimination of ground reflection to access the free-field sound pressure level, has been defined as one of the basic steps in aircraft noise prediction on the noise certification procedure by ICAO[1,. Based on the importance of the method, this paper will study the impact of the ground reflection effects on the aircraft engine noise experimental, especially made a detailed overview for the calculation method of reflective index.This paper also gives the method of fixing this effect to get the free field sound pressure level, while making experiments to verify the feasibility of this method, so that make the noise analysis and prediction according to the noise certification procedures.

scholarly journals First investigation on the applicability of an active noise control system on a tracked tractor without cab

2013 ◽  
Vol 44 (2s) ◽  
Author(s):  
Daniele Pochi ◽  
Roberto Fanigliulo ◽  
Lindoro Del Duca ◽  
Pietro Nataletti ◽  
Gennaro Vassalini ◽  
...  
Keyword(s):  
Sound Pressure Level ◽  
Digital Signal Processor ◽  
Sound Pressure ◽  
Engine Speed ◽  
Noise Control ◽  
Active Noise Control ◽  
Control Unit ◽  
Pressure Level ◽  
Maximum Speed ◽  
Active Noise

In last years, several research teams pointed their attention on the application of active noise control systems (ANC) inside the cabs of agricultural tractor, with the purpose of reducing the driver exposition to noise, that is only partially controlled by the frame of the cab. This paper reports the results of a first experience that aimed at verifying the applicability of an ANC on a medium-high power, tracked tractor without cab. The tested tractor was a Fiat Allis 150 A, equipped with rear power take off, used in the execution of deep primary tillage in compact soils. It is a tracked tractor without cab, with maximum power of 108.8 kW at 1840 min–1 of the engine. The ANC consists of a control unit box based on a digital signal processor (DPS), two microphones, two speakers and a power amplifier. The instrumentation used in noise data collecting and processing consisted of a multichannel signal analyzer (Sinus - Soundbook), a ½” microphone capsule and an acoustic calibrator, both Bruel & Kjaer. The study aimed at evaluating the behaviour of the ANC by means of tests carried out under repeatable conditions, characterized by pre-defined engine speed values. Three replications have been made for each engine speed. The sampling time was 30 s. Two series of tests were performed in order to compare the results observed with the ANC on and off. The engine speed adopted in the study ranged from 600 min– 1, up to 2000 min–1 (maximum speed) with steps of 100 min–1. The ANC proved to be effective in the interval of speed between 1400 and 1700 min–1, where the samplings have been intensified, adopting steps of 50 min–1. In such an interval, the attenuation observed with the ANC system on appeared evident both as weighed A sound pressure level (from 1.29 up to 2.46 dB(A)) and linear (from 4.54 up to 8.53 dB). The best performance has been observed at the engine speed of 1550 min–1, with attenuations, respectively of 2.46 dB(A) and 7.67 dB. Outside of the engine speed interval 1400 - 1700 min–1, the attenuations always resulted lower than 1 dB(A) for the weighed A sound pressure level and between 0.66 and 7.72 dB.

Optimization of the Location of Secondary Sources for the Active Engine Vibration Acoustic Noise Control in the Generator Room

2015 ◽  
Vol 766-767 ◽  
pp. 968-973
Author(s):  
T. Ramachandran ◽  
M.C. Lenin Babu
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Noise Control ◽  
Acoustic Noise ◽  
Active Noise Control ◽  
Pressure Level ◽  
Secondary Source ◽  
Secondary Sources ◽  
Quadratic Minimization ◽  
Room Model

The noise acoustic control in the interior of a diesel engine generator room model is studied and optimized. The finite element modelling and discretization of the engine room is carried out and the noise control is achieved using global active control of sound. The Genetic algorithm (GA) is used to find the optimized location of secondary sources to minimize the sound pressure level at receiver’s location. The secondary sources strengths for the active noise control system are computed using quadratic minimization acoustic potential energy. It is found that the sound pressure level at receiver’s location has been significantly reduced with changing the secondary source positions from arbitrarily to optimal location.

Contributions of Voice and Nonverbal Communication to Perceived Masculinity–Femininity for Cisgender and Transgender Communicators

2020 ◽  
Vol 63 (4) ◽  
pp. 931-947
Author(s):  
Teresa L. D. Hardy ◽  
Carol A. Boliek ◽  
Daniel Aalto ◽  
Justin Lewicke ◽  
Kristopher Wells ◽  
...  
Keyword(s):  
Fundamental Frequency ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Vocal Tract ◽  
Presentation Mode ◽  
Pressure Level ◽  
Presentation Modes ◽  
Audiovisual Stimuli ◽  
Vocal Tract Resonance ◽  
Point Light

Purpose The purpose of this study was twofold: (a) to identify a set of communication-based predictors (including both acoustic and gestural variables) of masculinity–femininity ratings and (b) to explore differences in ratings between audio and audiovisual presentation modes for transgender and cisgender communicators. Method The voices and gestures of a group of cisgender men and women ( n = 10 of each) and transgender women ( n = 20) communicators were recorded while they recounted the story of a cartoon using acoustic and motion capture recording systems. A total of 17 acoustic and gestural variables were measured from these recordings. A group of observers ( n = 20) rated each communicator's masculinity–femininity based on 30- to 45-s samples of the cartoon description presented in three modes: audio, visual, and audio visual. Visual and audiovisual stimuli contained point light displays standardized for size. Ratings were made using a direct magnitude estimation scale without modulus. Communication-based predictors of masculinity–femininity ratings were identified using multiple regression, and analysis of variance was used to determine the effect of presentation mode on perceptual ratings. Results Fundamental frequency, average vowel formant, and sound pressure level were identified as significant predictors of masculinity–femininity ratings for these communicators. Communicators were rated significantly more feminine in the audio than the audiovisual mode and unreliably in the visual-only mode. Conclusions Both study purposes were met. Results support continued emphasis on fundamental frequency and vocal tract resonance in voice and communication modification training with transgender individuals and provide evidence for the potential benefit of modifying sound pressure level, especially when a masculine presentation is desired.

Case study: Theoretical calculation model and variable condition analysis research on the water-splashing noise for natural draft wet cooling towers

2020 ◽  
Vol 68 (2) ◽  
pp. 137-145
Author(s):  
Yang Zhouo ◽  
Ming Gao ◽  
Suoying He ◽  
Yuetao Shi ◽  
Fengzhong Sun
Keyword(s):  
Theoretical Model ◽  
Sound Pressure Level ◽  
Water Droplet ◽  
Water Distribution ◽  
Sound Pressure ◽  
Cooling Tower ◽  
Distribution Patterns ◽  
Calculation Model ◽  
Pressure Level ◽  
Cooling Towers

Based on the basic theory of water droplets impact noise, the generation mechanism and calculation model of the water-splashing noise for natural draft wet cooling towers were established in this study, and then by means of the custom software, the water-splashing noise was studied under different water droplet diameters and water-spraying densities as well as partition water distribution patterns conditions. Comparedwith the water-splashing noise of the field test, the average difference of the theoretical and the measured value is 0.82 dB, which validates the accuracy of the established theoretical model. The results based on theoretical model showed that, when the water droplet diameters are smaller in cooling tower, the attenuation of total sound pressure level of the water-splashing noise is greater. From 0 m to 8 m away from the cooling tower, the sound pressure level of the watersplashing noise of 3 mm and 6 mm water droplets decreases by 8.20 dB and 4.36 dB, respectively. Additionally, when the water-spraying density becomes twice of the designed value, the sound pressure level of water-splashing noise all increases by 3.01 dB for the cooling towers of 300 MW, 600 MW and 1000 MW units. Finally, under the partition water distribution patterns, the change of the sound pressure level is small. For the R s/2 and Rs/3 partition radius (Rs is the radius of water-spraying area), when the water-spraying density ratio between the outer and inner zone increases from 1 to 3, the sound pressure level of water-splashing noise increases by 0.7 dB and 0.3 dB, respectively.

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