Effects of Sand Bed Anti-Vibration Mount on Transmitted Noise from Portable On-Site Electricity Generator

2020 ◽  
Vol 15 (2) ◽  
pp. 8-12
Author(s):  
A.S. Aremu ◽  
T.K. Amao ◽  
O.A. Mokuolu
Keyword(s):  
Particle Size ◽  
Noise Reduction ◽  
Fine Sand ◽  
Sound Level ◽  
Sand Particle ◽  
Particle Sizes ◽  
Noise Levels ◽  
Noise Measurements ◽  
Level Meter ◽  
Vibration Noise

This study investigated the effect of different particle sizes of sand bed anti-vibration mount on transmitted noise from a portable on-site electricity generator. Ten sand bed anti-vibration mounts, 650mm x 650mm in cross section and 75mm thickness were prepared with particle sizes ranging from 0.09 to 2.30mm. Noise measurements were taken in the four cardinal directions using Extech HD600 digital sound level meter. The results of the study showed that the ability of the sand particles to dampen vibration noise from the portable electricity generator reduces with increase in particle size. The sand bed anti-vibration mounts reduced noise levels by 0.11 to 2.78 dB(A). However, fine sand bed of particle size 0.09mm and 0.15mm exhibited superiority in noise reduction over all other sand beds. In order to achieve appreciable noise reduction, the use of ISO 14688-1:2002 fine sand category is recommended as anti-vibration mount in combination with other damping methods. Keywords: Electricity generator, noise, sand, particle size and attenuation

Effect of distance from road intersection on developed traffic noise levels

2004 ◽  
Vol 31 (4) ◽  
pp. 533-538 ◽  
Author(s):  
Saad Abo-Qudais ◽  
Arwa Alhiary
Keyword(s):  
Noise Level ◽  
Traffic Noise ◽  
Sound Level ◽  
Signalized Intersections ◽  
Environment Pollution ◽  
Noise Levels ◽  
The Road ◽  
Traffic Intersection ◽  
Noise Measurements ◽  
Level Meter

The main objective of this study was to evaluate the variation in traffic equivalent noise levels as distance from the road intersection increases. To achieve this objective, traffic volume and equivalent noise level were monitored at 40 signalized intersections in Amman, the capital of Jordan. An integrated sound level meter (ISLM) was used to measure 1 min equivalent noise level along all approaches of the evaluated intersections. A total of 3326 noise measurements were performed. The collected data were analyzed to evaluate the variation of noise levels as distance from the intersection increases. The results indicated that equivalent noise levels were significantly affected by distance from the signal stop line. The equivalent noise levels at distances 50 and 100 m from the intersection were found to be 1.5 to 2.0 dB less than those at 0 m. While at 200, 250, and 300 m from the intersection, the monitored equivalent noise levels were found to be 3.8 to 4 dB higher than that at 0 m. At distances farther than 250 m, the measured equivalent noise levels tend to keep constant value of equivalent noise level as distance increased.Key words: noise, traffic, intersection, environment, pollution.

scholarly journals Case Study in a Working Environment Highlighting the Divergence between Sound Level and Workers’ Perception towards Noise

2020 ◽  
Vol 17 (17) ◽  
pp. 6122
Author(s):  
Chun-Yip Hon ◽  
Illia Tchernikov ◽  
Craig Fairclough ◽  
Alberto Behar
Keyword(s):  
Noise Exposure ◽  
Health And Safety ◽  
Sound Level ◽  
Working Environment ◽  
Noise Levels ◽  
Hearing Conservation ◽  
Attitudes And Perceptions ◽  
Noise Measurements ◽  
Survey Responses ◽  
Excessive Noise

Excessive noise levels are a prevalent issue in food processing operations and, although there have been numerous studies on occupational noise, no single study has used a concurrent mixed-methods approach. Employing this study design allows for an understanding of the level of convergence (similarity) between measured noise levels and workers’ attitudes and perceptions towards noise. This, in turn, allows for the identification of potential challenges with respect to the implementation of hearing conservation efforts. In this study, spot noise measurements were collected using a sound level meter. One-on-one interviews were conducted with workers to determine attitudes and perceptions towards noise in their workplaces. Subsequently, the results of the noise measurements (quantitative data) were integrated with the survey responses (qualitative data) to identify convergence. The majority of the noise measurements were found to exceed 85 dBA—the criterion mandated by the local occupational health and safety legislation. Although all study participants felt that it was noisy in the workplace, a large proportion of respondents indicated that the noise was not bothersome. With workers’ perception being contradictory to the measured noise levels, it is a challenge to implement hearing conservation measures unless changes are made to raise the awareness of the risks associated with excessive noise exposure.

S254 – Bone Conduction Noise Exposure via Ventilators in the NICU

2008 ◽  
Vol 139 (2_suppl) ◽  
pp. P160-P160
Author(s):  
Angela P Black ◽  
James D Sidman
Keyword(s):  
Ambient Noise ◽  
Noise Exposure ◽  
Bone Conduction ◽  
Sound Level ◽  
Noise Levels ◽  
High Noise ◽  
Endotracheal Tubes ◽  
Level Meter ◽  
Hearing Damage ◽  
Air Conduction

Objectives To demonstrate that neonatal ventilators produce high noise levels through bone conduction (BC) via endotracheal tubes, as well as air conduction (AC) from ambient noise. Methods A sound level meter was used to measure the noise levels 4 feet from the ventilator and in direct contact at the end of a balloon attached to the ETT to simulate the noise presented to the infant. 3 commonly used neonatal ventilators (Sensormedics 3100A, VIP Bird and Bunnell Jet) were examined. Results Noise levels were significantly higher (6 – 14 dB) at the end of the ETT than 4 ft from the ventilator for all ventilators studied. Conclusions Previous studies have shown high ambient noise levels in NICUs, but have failed to address the actual noise presented to the infant. ETT transmission of noise as a direct bone stimulus through the skull has been overlooked. This study has shown that high noise intensities are being presented not only as AC, but as BC to the infants though the ETT. This study demonstrates, therefore, that ear protection alone will not save these at-risk infants from hearing damage. More must be done to decrease noise exposure and develop quieter machines.

Experimental and CFD Investigations to Evaluate the Effects of Fluid Viscosity and Particle Size on Erosion Damage in Oil and Gas Production Equipment

2010 ◽  
Author(s):  
Risa Okita ◽  
Yongli Zhang ◽  
Brenton S. McLaury ◽  
Siamack A. Shirazi ◽  
Edmund F. Rybicki
Keyword(s):  
Particle Size ◽  
Oil And Gas ◽  
Production Equipment ◽  
Gas Production ◽  
Inconel 625 ◽  
Sand Particle ◽  
Fluid Viscosity ◽  
Particle Sizes ◽  
Erosion Rates ◽  
Particle Speed

Zhang et al (2006) utilized CFD to examine the validity of erosion models that have been implemented into CFD codes to predict solid particle erosion in air and water for Inconel 625. This work is an extension of Zhang’s work and is presented as a step toward obtaining a better understanding of the effects of fluid viscosity and sand particle size on measured and calculated erosion rates. The erosion rates of Aluminum 6061-T6 were measured for direct impingement conditions of a submerged jet. Fluid viscosities of 1, 10, 25, and 50 cP and sand particle sizes of 20, 150, and 300 μm were tested. The average fluid speed of the jet was maintained at 10 m/s. Erosion data show that erosion rates for the 20 and 150 μm particles are reduced as the viscosity is increased, while surprisingly the erosion rates for the 300 μm particles do not seem to change much for the higher viscosities. For all viscosities considered, larger particles produced higher erosion rates, for the same mass of sand, than smaller particles. Concurrently, an erosion equation has been generated based on erosion testing of the same material in air. The new erosion model has been compared to available models and has been implemented into a commercially available CFD code to predict erosion rates for a variety of flow conditions, flow geometries, and particle sizes. Since particle speed and impact angle greatly influence erosion rates of the material, calculated particle speeds were compared with measurements. Comparisons reveal that, as the particles penetrate the near wall shear layer, particles in the higher viscosity liquids tend to slow down more rapidly than particles in the lower viscosity liquids. In addition, CFD predictions and particle speed measurements are used to explain why the erosion data for larger particles is less sensitive to the increased viscosities.

scholarly journals Assessment of traffic noise due to transverse rumble strips at residential areas

2018 ◽  
Vol 250 ◽  
pp. 02006
Author(s):  
Zaiton Haron ◽  
Darus Nadirah ◽  
Supandi Mohamad Afif ◽  
Yahya Khairulzan ◽  
Nordiana Mashros ◽  
...  
Keyword(s):  
Noise Level ◽  
Traffic Noise ◽  
Middle Layer ◽  
Sound Level ◽  
Skid Resistance ◽  
Residential Areas ◽  
Noise Levels ◽  
Traffic Characteristics ◽  
Level Meter ◽  
Road Characteristics

Transverse rumble strips (TRS) are commonly being installed to alert the drivers through sound and vibration effects. The sound produced affects the existing traffic noise level which caused noise annoyance to the nearby residents. This study aims to assess the traffic noise due to TRS at residential areas by determining the roadside noise levels, traffic and road characteristics and evaluating the relationship between these parameters. Middle overlapped (MO), middle layer overlapped (MLO) and raised rumbler (RR) TRS profiles with same thickness were selected. The measurements of roadside noise levels and skid resistance were conducted using sound level meter (SLM) and British pendulum tester (BPT) respectively. Traffic characteristics were evaluated using previous data measured using automatic traffic counter (ATC). In overall, MLO produced highest roadside noise levels with increase of 20.5dBA from baseline. Generally, the increase of roadside noise level due to TRS is strong with speed, weak to medium with skid resistance of TRS and no relationship with traffic volume. Based on three TRS profile types, MLO is not suitable to be installed on the roadways adjacent to the residential areas as the increase of roadside noise level is significant which is more than 5dBA compared to MO and RR.

How Well Mobile Phone App DecibelX Measures Noise and the Usability Study

2019 ◽  
Author(s):  
Ravinder Thaper ◽  
Murray Gibson ◽  
Mathew Reed ◽  
Wallace Morris ◽  
Aravind Reddy Putta
Keyword(s):  
Pure Tone ◽  
Narrow Band ◽  
Sound Level ◽  
Smartphone App ◽  
Usability Study ◽  
Sound Level Meter ◽  
Noise Levels ◽  
Traditional Use ◽  
Band Noise ◽  
Level Meter

This study aims to assess using a smartphone app (DecibelX), as a noise measuring alternative to the more costly traditional use of measuring noise levels with a Sound Level Meter (SLM). The study compares the accuracy of the app to readings taken with a SLM and dosimeter, and also evaluates the app’s performance for pure tone and narrow band noise. And a usability study identifies strengths and weaknesses related to usability of the app.

scholarly journals Computer Simulation of Volume Shrinkage after Mixing Container Media Components

1993 ◽  
Vol 118 (6) ◽  
pp. 757-761 ◽  
Author(s):  
Silvia Burés ◽  
Franklin A. Pokorny ◽  
David P. Landau ◽  
Alan M. Ferrenberg
Keyword(s):  
Experimental Data ◽  
Computer Simulation ◽  
Particle Size ◽  
Monte Carlo ◽  
Particle Size Distribution ◽  
Experimental System ◽  
Fine Sand ◽  
Spherical Particles ◽  
Particle Sizes ◽  
Coarse Particles

A FORTRAN computer program was developed to simulate packing of spherical particles via a Monte Carlo procedure. Shrinkage in volume upon mixing different particle sizes was studied and simulated results were compared with experimental data. Maximum experimental shrinkage was obtained when the proportion of coarse particles of pine bark and sand mixtures ranged from 50% to 70% of the volume. Experimental shrinkage of a mixture of coarse and fine sand was closely reproduced by means of simulation. Particle size distribution appears to be the most important factor in relation to shrinkage and also in the establishment of relationships between the simulated and the experimental system.

scholarly journals Mineralogy (XRD)

2021 ◽  
pp. 95-119
Author(s):  
Ali Al-Dousari ◽  
Muntha Bahbahani
Keyword(s):  
Particle Size ◽  
Clay Minerals ◽  
Fine Sand ◽  
Sand Particle ◽  
List Type ◽  
Mineralogical Analysis ◽  
Mineral Concentration ◽  
Average Percentage ◽  
Mineral Concentrations ◽  
Mineral Constituents

Abstract The two main particle size components of the dust samples were subjected to mineralogical analysis to identify the mineral constituents and determine their frequency percentage in each textural class; the fine sand (particle size between 0.125 and 0.063 mm) and Mud (less than 0.063 mm). The average percentage of minerals was mapped out for each season i.e. March, June, September and December 2010 showing the high and low mineral concentration in areas in Kuwait covering the mineral concentrations of Calcite, Carbonate, clay minerals, dolomite, feldspars, and quartz.

scholarly journals Noise Pollution in Urban Residential Environments: Evidence from Students’ Hostels in Awka, Nigeria

2021 ◽  
Vol 12 (1) ◽  
pp. 51-62
Author(s):  
Nicholas OBI ◽  
◽  
Joy Sylvia OBI ◽  
Eziyi IBEM ◽  
Dickson NWALUSI ◽  
...  
Keyword(s):  
Urban Areas ◽  
Residential Buildings ◽  
Noise Pollution ◽  
Sound Level ◽  
Noise Levels ◽  
Noise Sources ◽  
Chi Square ◽  
Sound Barriers ◽  
Level Meter ◽  
Area Data

Noise pollution and its concomitant effects on humans and environment has reached dangerous levels in many urban areas across the world. However, very little is known about the sources and effects of noise pollution within students’ hostels in a developing country like Nigeria. This study investigated urban noise pollution in residential neighbourhoods, using the Nnamdi Azikiwe University students’ off-campus accommodation in Awka, southeast Nigeria as the study area. Data were obtained through measurements of noise levels using sound level meter and by conducting a survey to gather feedback from 260 students in the study area. Descriptive statistics and Chi-Square tests were used to analyse the data; the results revealed mean noise levels of 89.8 dB(A) and 46.9 dB(A) during noisy and quiet periods, respectively. The main sources of noise were portable electricity generators, vehicular traffic and loudspeakers used by students and business operators; they were found to have deleterious effects such as low tolerance, headache, anger, lack of concentration and low productivity on the students. The study concludes by noting that to effectively minimize the effects of noise pollution within urban residential neighbourhoods in the study area and beyond, architects and urban planners should engage in proper land use zoning and the application of sound absorbing materials on walls and locating balconies of residential buildings away from noise sources. In addition, vegetation belts and sound barriers of earth mounds or wood, metal or concrete could also be constructed between the sources of noise and residential buildings, especially in the case of roadside communities.

scholarly journals Field Study of the Noise Exposure Inside Running Metro Unit

2021 ◽  
Vol 7 (3) ◽  
pp. 560-574
Author(s):  
Mohamed N. Younes ◽  
Ali Z. Heikal ◽  
Akram S. Kotb ◽  
Haytham N. Zohny
Keyword(s):  
Noise Exposure ◽  
Sound Level ◽  
Noise Levels ◽  
Severe Damage ◽  
Acoustic Environment ◽  
Factors Affecting ◽  
Greater Cairo ◽  
Train Speed ◽  
Level Meter

The noise levels inside metro units are considered a significant problem that makes passengers suffer from severe damage, especially for those who use the metro periodically. This research evaluates the acoustic environment inside the metro car and studies factors affecting the noise levels inside metro units and developing models for estimate noise in the metro unit while moving between stations. Greater Cairo Metro (GCM) Line 1 has been selected as a case study. A sound level meter was used to measure the equivalent sound level in dBA and evaluate the noise inside metro units. The results indicate that the noise levels are unacceptable compared with the international noise exposure standards. The highest measured noise level inside metro units is 91.2 dBA. These unacceptable noise levels led to more investigation of factors that may affect noise levels inside metro units. Other data have been collected, such as the speed of the train and the track alignment details. The results showed that the noise increases with the increase of the train speed until the speed reaches a specific value, then it decreases depending on the maintenance status and the train type. In addition, the noise levels through curved underground tracks are higher than the levels along straight surface tracks by 18 dB(A). Doi: 10.28991/cej-2021-03091674 Full Text: PDF

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