Using Ceramic Balls to Reduce Noise in a Linear Guideway Type Recirculating Linear Ball Bearing

2003 ◽  
Vol 125 (3) ◽  
pp. 480-486 ◽  
Author(s):  
Hiroyuki Ohta ◽  
Takumi Nakagawa
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Ball Bearing ◽  
Pressure Level ◽  
Linear Velocity ◽  
Sound Frequency ◽  
Experimental Results ◽  
New Method ◽  
Sound Pressure Levels ◽  
Steel Balls

A new method of reducing the noise of the linear guideway type recirculating linear ball bearing (linear bearing) was studied. In the experiments, the overall sound pressure levels of linear bearings with steel balls or ceramic Si3N4 balls were measured, and sound frequency analyses were carried out. Moreover, based on the assumption that the main cause of the noise may be the collision between the ball and the carriage, the overall sound pressure levels of the linear bearings were analyzed combining the Hertzian theory and the results of previous studies on collision sound. From the results of experiments and analyses, the conclusions were obtained as follows: (1) The overall sound pressure level of the linear bearing with steel balls can be reduced by about 4.5 dB by using Si3N4 balls having the same diameter; (2) The overall sound pressure levels of linear bearings with steel balls or ceramic Si3N4 balls were both increased by about 9.8 dB as the linear velocity increased an octave; and (3) The analytical results, based on the assumption that the main cause of the noise emitted from the linear bearings is the collision between the ball and the carriage, match the experimental results well.

Sound of Linear Guideway Type Recirculating Linear Ball Bearings

1999 ◽  
Vol 121 (4) ◽  
pp. 678-685 ◽  
Author(s):  
Hiroyuki Ohta
Keyword(s):  
Sound Pressure Level ◽  
Sound Source ◽  
Sound Pressure ◽  
Natural Vibration ◽  
Ball Bearing ◽  
Pressure Level ◽  
Linear Velocity ◽  
Ball Bearings ◽  
Rate Of Increase ◽  
Measurement Results

The sound characteristics of linear guideway type (LGT) recirculating linear ball bearing driven at a constant linear velocity was studied. The measurement results of the sound characteristics showed that the LGT recirculating linear ball bearing has a sound property between line sound source and point sound source, and the measured overall sound pressure level increases with increasing the linear velocity of the carriage. The rate of increase of the overall sound pressure level to the linear velocity was analyzed combining the deduction of Yamada et al. and the results of previous studies on the collision sound. The results of this analysis match roughly the rate of increase of the measured overall sound pressure level to the linear velocity. We also observed the main peaks in the sound spectra of the LGT recirculating linear ball bearing itself. As a result, it was made clear that the main peaks are caused by the lower rolling natural vibration of the carriage, the pitching natural vibration of the carriage, and the vertical natural vibration of the carriage. In addition, the frequencies of the main peaks can be estimated by using presented expressions fRL, fP, and fv.

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

Thickness-resonance waves in underlays of floating screed

2021 ◽  
Vol 263 (3) ◽  
pp. 2973-2983
Author(s):  
Charlotte Crispin ◽  
Debby Wuyts ◽  
Dijckmans Arne
Keyword(s):  
Finite Element ◽  
Transfer Matrix ◽  
Sound Pressure Level ◽  
Transfer Matrix Method ◽  
Matrix Method ◽  
Sound Pressure ◽  
Pressure Level ◽  
Experimental Results ◽  
Simplified Model ◽  
Negative Effects

The prediction of the reduction of impact sound pressure level ΔL according to annex C of the standard ISO 12354-2 gives an acceptable estimation of the floating floor's performance for thin resilient layers. However, the performance is often largely overestimated for thick resilient layers or for resilient layers combined with thermal layers. One reason for this is that the simplified model doesn't account for the thickness resonances in the underlays which can greatly affect ΔL. This is confirmed by comparing finite element and transfer matrix method simulations with experimental results. This paper establishes the mechanisms leading to the development of these resonance waves and provides some guidelines to estimate their negative effects on the ΔL.

Variation in vibro-acoustic noise due to the defects in an automotive drum brake

2021 ◽  
Vol 263 (4) ◽  
pp. 2646-2653
Author(s):  
Ananthapadmanabhan Ramesh ◽  
Sundar Sriram
Keyword(s):  
Analytical Model ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Transfer Functions ◽  
Acoustic Noise ◽  
Pressure Level ◽  
Acoustic Model ◽  
Drum Brake ◽  
Non Linear ◽  
Sound Pressure Levels

Drum brakes are significant contributors to noise and vibration in automobiles causing discomfort to the passengers. The vibration and hence the resulting noise increase due to various inherent defects in the drum brake, such as asymmetry. This work aims to quantify the variation in the vibro-acoustic noise due to several common defects in the drum brake using an integrated non-linear vibration analytical model and a numerical acoustic model. The sources of vibro-acoustic noise sources such as contact and reaction forces are predicted using a four-degree-of-freedom non-linear contact mechanics based analytical model. A finite element based acoustic model of the drum brake is utilized to predict the force to the sound pressure transfer function in the drum brake. Product of the transfer functions and the forces gives the corresponding sound pressure level from which the overall sound pressure levels are estimated. The variation in the overall sound pressure levels due to different drum brake defects is evaluated by introducing defects to the analytical model. The results show that the overall sound pressure level is a strong function of the defects. It is envisioned that the current work will help in the development of effective health monitoring systems.

Gyro Rock Crusher and Asphalt Plant Sound Power Levels

2012 ◽  
Author(s):  
Henry A. Scarton ◽  
Kyle R. Wilt
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Low Frequency ◽  
Pressure Level ◽  
Sound Power ◽  
Far Field ◽  
Atmospheric Attenuation ◽  
Frequency Sound ◽  
Sound Pressure Levels ◽  
Rock Crusher

Sound power levels including the distribution into octaves from a large 149 kW (200 horsepower) gyro rock crusher and separate asphalt plant are presented. These NIST-traceable data are needed for estimating sound pressure levels at large distances (such as occurs on adjoining property to a quarry) where atmospheric attenuation may be significant for the higher frequencies. Included are examples of the computed A-weighted sound pressure levels at a distance from the source, including atmospheric attenuation. Substantial low-frequency sound power levels are noted which are greatly reduced in the far-field A-weighted sound pressure level calculations.

The effect of acoustic field on the particle concentration profiles in fluidized bed

2012 ◽  
Vol 10 (1) ◽  
Author(s):  
Chongdian Si ◽  
Jing Zhou ◽  
Qingjie Guo ◽  
Guangjun Liu
Keyword(s):  
Fluidized Bed ◽  
Acoustic Field ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Particle Concentration ◽  
Sine Wave ◽  
Pressure Level ◽  
Sound Frequency ◽  
Concentration Profiles ◽  
Wave Forms

Abstract The particle concentration profiles were investigated using an optical fiber probe in a fluidized bed with acoustic assistance. The effects of sound frequency, sound pressure level, and sound wave forms on the particle concentration profiles were researched. Experimental results indicated that the application of an acoustic field could remarkably influence the particle concentration profiles in a fluidized bed. The particle concentration increased with increasing sound pressure level. However, the particle concentration was highest at sound frequency of 150 Hz, and decreased towards both low and high frequency. Compared with Square wave, both Sine wave and Triangle wave can enhance particle concentration in radial and axial profiles.

scholarly journals Noise Emissions in Milking Parlours with Various Construction Solutions

2016 ◽  
Vol 19 (2) ◽  
pp. 49-51
Author(s):  
Marie Šístková ◽  
Martin Pšenka ◽  
Ivo Celjak ◽  
Petr Bartoš ◽  
Štefan Mihina ◽  
...  
Keyword(s):  
Dairy Cows ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Noise Exposure ◽  
Pressure Level ◽  
Different Types ◽  
Sound Pressure Levels ◽  
Mechanical Devices

Abstract Mechanical devices in parlours are a source of noise, and this noise has an effect not only on the operators of the parlour but also on dairy cows. They have more sensitive hearing than humans. The aim of this article was to analyse the sound pressure level and determine the noise exposure of dairy cows at different technological solutions of milking parlours, during their day routine. In the experiment, tandem, herringbone and rotary milking parlours were used. Noise exposure was measured during the milking process. After evaluation of noise pressure levels of different types of milking parlours, it can be concluded that in this experiment, the equivalent noise pressure level was lowest in the tandem milking parlour. Equivalent sound pressure levels in the rotary and herringbone milking parlour were almost about the same values. These values are higher than values in the tandem milking parlour, about 10 decibels. The differences within mean LAFeq values between the herringbone milking parlour and tandem milking parlour were highly statistically significant (P <0.001***).

scholarly journals “Horário do Soninho”: uma estratégia para reduzir os níveis de pressão sonora em uma unidade de terapia intensiva neonatal

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Adriana Duarte Rocha ◽  
Patricia Miranda Sá ◽  
Danielle Bonotto Cabral Reis ◽  
Ana Carolina Carioca Costa
Keyword(s):  
Intensive Care ◽  
Sound Pressure Level ◽  
Sound Pressure ◽  
Pressure Level ◽  
Quiet Time ◽  
Cross Sectional ◽  
Significant Difference ◽  
Sound Pressure Levels ◽  
Terapia Intensiva ◽  
Tiempo De Silencio

ResumoIntrodução: Estudos mostram que o ambiente muito estimulante, com altos níveis sonoros, interfere negativamente no desenvolvimento e crescimento de recém-nascidos. Objetivo: verificar se o "horário do soninho" é capaz de reduzir os níveis de pressão sonora em uma unidade de cuidados neonatais. Método: Trata-se de uma pesquisa transversal. A medida do nível de pressão sonora foi realizada durante 15 dias não consecutivos, com tempo de avaliação de 30 minutos antes, 1 hora durante e 30 minutos após o "horário do soninho" Resultado: Observamos uma redução dos níveis de pressão sonora durante o "horário do soninho" (p = 0,00). Essa redução permaneceu no período dos 30 minutos subsequentes, com diferença estatisticamente significante quando comparada ao período antes do "horário do soninho" (p = 0,00). Conclusão: O "horário do soninho" é uma ferramenta capaz de reduzir o nível de pressão sonora em uma unidade de terapia intensiva neonatalPalavras-Chave: ruído; Terapia Intensiva neonatal; Recém-nascido AbstractBackground: Studies show that super stimulating environment, with high sound levels, that negatively interfere in the development and growthof newborns. Aim:  Verify if the "quiet time" is able to reduce the sound pressure levels in a neonatal care unit. Method: It is a cross-sectional research. The measurement of the sound pressure level was performed during 15 non-consecutive days with an evaluation time of 30 minutes before, 1 hour during and 30 minutes after the "quiet time" Result: We observed a reduction of the sound pressure levels during the hours of quiet time (p = 0.00). This reduction remained in the period of the subsequent 30 minutes, with a statistically significant difference when compared to the period before sleep time (p = 0.00). Conclusion: The “quiet time is a tool capable of reducing sound pressure level in a neonatal intensive care unitKey Words: noise; Intensive Care, neonatal; Infant, newborn Resumen"Tiempo de silencio": una herramienta para reducir los niveles de presión acústica en una unidad de cuidados intensivos neonatalesAntecedentes: los estudios muestran que el entorno súper estimulante, con altos niveles de sonido, interfiere negativamente en el desarrollo y crecimiento de los recién nacidos. Objetivo: Verificar si el "tiempo de silencio" puede reducir los niveles de presión acústica en una unidad de cuidados neonatales. Método: es una investigación transversal. La medición del nivel de presión sonora se realizó durante 15 días no consecutivos con un tiempo de evaluación de 30 minutos antes, 1 hora durante y 30 minutos después del "tiempo de silencio" Resultado: Observamos una reducción de los niveles de presión sonora durante las horas de tiempo de silencio (p = 0.00). Esta reducción se mantuvo en el período de los siguientes 30 minutos, con una diferencia estadísticamente significativa en comparación con el período anterior al tiempo de sueño (p = 0,00). Conclusión: el “tiempo de silencio es una herramienta capaz de reducir el nivel de presión acústica en una unidad de cuidados intensivos neonatales Palabras clave: ruido; Cuidados Intensivos, neonatales; Infante, recién nacido

Parameterization of the Voice Source by Combining Spectral Decay and Amplitude Features of the Glottal Flow

1998 ◽  
Vol 41 (5) ◽  
pp. 990-1002 ◽  
Author(s):  
Paavo Alku ◽  
Erkki Vilkman ◽  
Anne-Maria Laukkanen
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Pressure Level ◽  
New Method ◽  
Inverse Filtering ◽  
Voice Production ◽  
Voice Source ◽  
Volume Velocity ◽  
Glottal Flow ◽  
The Voice

A new method is presented for the parameterization of glottal volume velocity waveforms that have been estimated by inverse filtering acoustic speech pressure signals. The new technique, Parameter for Spectral and Amplitude Features of the Glottal Flow (PSA), combines two features of voice production, the AC value and the spectral decay of the glottal flow, both of which contribute to changes in vocal loudness. PSA yields a single parameter that characterizes the glottal flow in different loudness conditions. By analyzing voices of 8 speakers it was shown that the new parameter correlates strongly with the sound pressure level of speech.

The Role of Static Pressure and Temperature in Building Acoustics

2003 ◽  
Vol 10 (2) ◽  
pp. 159-176 ◽  
Author(s):  
Volker Wittstock ◽  
Christian Bethke
Keyword(s):  
Sound Pressure Level ◽  
Sound Pressure ◽  
Static Pressure ◽  
Meteorological Conditions ◽  
Pressure Level ◽  
Shell Structures ◽  
Noise Levels ◽  
Sound Pressure Levels ◽  
Sound Reduction ◽  
Reduction Index

The influence of static pressure and temperature on sound reduction indices, impact sound pressure levels, improvements of impact sound pressure levels and sound reduction indices, and relative installation noise levels is investigated. Theory revealed a systematic influence on sound reduction index and normalized impact sound pressure level. Firstly, the sound power radiated by a vibrating structure is directly proportional to the sound impedance in air and therefore to static pressure and temperature to the power of −0.5. Secondly, the sound pressure produced in a room by a sound source also depends on sound impedance, i.e. on static pressure and temperature. Since the excitation of a test specimen is not influenced by static pressure or temperature, the two effects are not compensated by any other mechanism, thus temperature and static pressure also influence sound reduction index and normalized impact sound pressure level. Experimental verification involved measurement of sound reduction index in a small test suite at static pressures between 307 and 970 hPa. Measurement results for single-shell structures showed the expected behaviour, whereas results for double-shell structures revealed a considerable scatter with a tendency towards even larger temperature and static pressure influences. For comparison of the acoustic properties of building elements, it is therefore advisable to introduce a normalized sound reduction index and a normalized impact sound pressure level, with both referred to reference conditions of static pressure and temperature. Improvements in impact sound pressure levels and sound reduction index, and relative installation noise levels are determined from changes in sound level differences. Since each difference is influenced in the same manner by meteorological conditions, the resulting improvement is independent of static pressure and temperature, as long as the differences were determined under the same meteorological conditions.

Sign in / Sign up

Export Citation Format

Share Document