Attenuation of Continuous Vibration Transmission in the Hand and Arm Using Composite-Based Tool Designs

Exposure to high noise levels may be the most common occupational hazard. Recent estimates suggest that as many as 30 million Americans are exposed to noise levels greater than the current safe limits for workplaces. At current durations of exposure, it is expected that 25% of these workers will develop permanent, noise-induced hearing loss. In many of these industrial environments, high levels of vibration also exist that can lead to several injuries and ailments. To address the adverse effects associated with the use of high noise emission impact tools, a study was initiated to develop and evaluate alternate tool designs that reduce the potential for hearing loss and vibration-related injuries. Recent work has focused on integrating advanced engineering polymers (composites) into tool designs for the purpose of eliminating direct metal-to-metal impact. This approach has several significant performance advantages including reduced operator discomfort due to hand-arm mechanical shock, reduced noise, and less danger from flying metal fragments. To quantify sound emission characteristics of these new designs, continuous sound pressure, maximum sound pressure, and maximum sound pressure level were measured using an array of five precision microphones each located 1 meter from the tool. Data was sampled at 40 kHz while test subjects operate both pneumatic tools and hand-struck tools. Frequency spectra of the sound pressure signals were examined for all tool treatments, and indicate that the addition of a polymer insert between metal impact components significantly reduces noise emission, especially at higher frequencies. Sound pressure levels were reduced by as much as 4 dBA compared to conventional tool designs. Similar reductions were observed in vibration transmission in the hand and arm. As a result, tools that integrate polymer-based components may be operated for longer daily exposure times without inducing hearing loss or vibration-related injuries. Data from this study may also help auditory and ergonomic specialists in understanding impulse noise characteristics and exposure.

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Polymer Composite-Based Vibration and Noise Emission Controls for Hand-Struck Impact Tools

Volume 4: ASME/IEEE International Conference on Mechatronic and Embedded Systems and Applications and the 19th Reliability, Stress Analysis, and Failure Prevention Conference ◽

10.1115/detc2007-35699 ◽

2007 ◽

Author(s):

Matthew Griffith ◽

Daniel Brisach ◽

Janelle Konchar ◽

Stephen Petfield ◽

Peter Popper ◽

...

Keyword(s):

Hearing Loss ◽

Sound Pressure ◽

Mechanical Shock ◽

Noise Levels ◽

Noise Emission ◽

Frequency Spectra ◽

High Noise ◽

Noise Characteristics ◽

Engineering Polymers ◽

Metal Impact

Exposure to high noise levels may be the most common occupational hazard. Recent estimates suggest that as many as 30 million Americans are exposed to noise levels greater than the current safe limits for workplaces. At current durations of exposure, it is expected that 25% of these workers will develop permanent, noise-induced hearing loss. In many of these industrial environments, high levels of vibration also exist that can lead to several injuries and ailments. To address the adverse effects associated with the use of high noise emission impact tools, a study was initiated to develop and evaluate alternate tool designs that reduce the potential for hearing loss and vibration-related injuries. Recent work has focused on integrating advanced engineering polymers (composites) into tool designs for the purpose of eliminating direct metal-to-metal impact. This approach has several significant performance advantages including reduced operator discomfort due to hand-arm mechanical shock, reduced noise, and less danger from flying metal fragments. To quantify sound emission characteristics of these new designs, continuous sound pressure, maximum sound pressure, and maximum sound pressure level were measured using an array of five precision microphones each located 1 meter from the tool. Data was sampled at 40 kHz while test subjects operate both pneumatic tools and hand-struck tools. Frequency spectra of the sound pressure signals were examined for all tool treatments, and indicate that the addition of a polymer insert between metal impact components significantly reduces noise emission, especially at higher frequencies. Similar reductions were observed in vibration transmission in the hand and arm. As a result, tools that integrate polymer-based components may be operated for longer daily exposure times without inducing hearing loss or vibration-related injuries. Data from this study may also help auditory and ergonomic specialists in understanding impulse noise characteristics and exposure.

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Discrete Frequency Noise From Lifting Fans

Journal of Engineering for Power ◽

10.1115/1.3445603 ◽

1971 ◽

Vol 93 (4) ◽

pp. 431-440

Author(s):

A. N. Abdelhamid

Keyword(s):

Sound Pressure ◽

Frequency Noise ◽

Noise Emission ◽

Aerodynamic Forces ◽

Fan Noise ◽

Unsteady Forces ◽

Discrete Frequency ◽

Unsteady Aerodynamic ◽

Noise Characteristics ◽

Good Agreement

Discrete frequency noise characteristics of a research lifting fan is investigated analytically. Based on steady aerodynamic data of the fan, unsteady aerodynamic forces acting on the rotor and stator blades were calculated using the results of previous investigators and an analysis which determines the effect of fluctuating velocity disturbance parallel to blade chord on the unsteady lift of cambered thin airfoils. The calculated unsteady forces were then used to determine the characteristics of discrete frequency noise emission from the fan. For the fan under consideration it is shown that the rotor interaction noise dominates the fan noise. Comparison between the predicted sound pressure levels and experimental observations shows good agreement. Based on the calculated detailed contributions of the different force harmonics acting on the blades to the fan noise, possible means of reducing lifting fan noise are discussed.

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3 Elaboración del mapa de ruido de las calles de la ciudad de Cuenca, a de partir de características viales y densidad de tráfico.

UNIVERSIDAD VERDAD ◽

10.33324/uv.v1i73.36 ◽

2017 ◽

pp. 39-49

Author(s):

Christian Tacuri Ortega ◽

Felipe Calderón Peralvo ◽

Julia Martínez Gavilanes ◽

Chester Sellers Walden ◽

Omar Delgado Inga

Keyword(s):

Sound Pressure ◽

Vehicular Traffic ◽

Noise Levels ◽

High Noise ◽

The Road ◽

Palabras Clave ◽

Car Park ◽

Progressive Growth ◽

Road Characteristics ◽

The City

Debido al progresivo crecimiento del parque automotor en la ciudad de Cuenca-Ecuador, se evidencian congestiones por la sobresaturación del tráfico en las vías de la ciudad, las cuales colapsan en horas pico, ocasionando, como consecuencia, elevados niveles de ruido. Por esta razón, el presente artículo tiene como objeto modelar el ruido generado por el tráfico vehicular en las principales calles de la ciudad. Para ello se utilizará el modelo de predicción de ruido NMPB-Routes-96 en el software especializado en ruido “Datakustik CadnaA”; para el efecto se ha realizado un levantamiento de los datos requeridos por el software, además de validar, depurar y sistematizar la información de la geodatabase proporcionada por la Dirección Municipal de Tránsito y Transporte (DMT) del GAD municipal de Cuenca, en la cual hay información sobre las características viales y del parque auto motor de la ciudad. Palabras clave: Ruido, mapa, CadnaA, nivel de presión sonora. AbstractDue to the progressive growth of the car park in the city of Cuenca-Ecuador, there is evidence of congestion due to the over-saturation of traffic on the city’s roads, which collapse in peak hours, resulting in high noise levels, resulting in high noise levels. For this reason, this article aims to model the noise generated by vehicular traffic in the main streets of the city, using the noise prediction model NMPB-Routes-96 in the specialized noise software “Datakustik CadnaA”, for this purpose a survey of the data required by the software has been carried out, besides validating, debugging and systematizing of the geodatabase information provided by the Municipal Transit and Transport Department (DMT) of the municipal GAD of Cuenca , in which there is information about the road characteristics and of the automotive park of the city. keywords: Noise, map, CadnaA, sound pressure level.

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Modeling of Woodworkers’ Exposure to Occupational Noises by Integrating Frequency Spectra Generated by Power Tools: A Pilot Study

Applied Sciences ◽

10.3390/app10186453 ◽

2020 ◽

Vol 10 (18) ◽

pp. 6453

Author(s):

Yu-Ping Zheng ◽

Yow-Jer Juang ◽

Lih-Ming Yiin

Keyword(s):

Pilot Study ◽

Tool Use ◽

Noise Exposure ◽

Noise Levels ◽

Frequency Spectra ◽

Occupational Noise Exposure ◽

Circular Saw ◽

Noise Characteristics ◽

Power Tools ◽

Convenient Dose

Woodwork is one of the occupations with high levels of noises. This pilot study attempted to simulate woodworkers’ occupational noise exposure by integrating frequency spectra measured from individual power tools with the respective time of tool use. Five volunteering woodworkers participated in the study, and each wore a noise dosimeter with 1/1 octave-band analysis during the work for exposure assessment. The information of use of tools and time of tool use was recorded by an on-site technician. Frequency spectra of common power tools, including circular saw, electric curve saw, orbit sander, router trimmer, drill machine, pillar drill machine, nail gun, and air compressor, were also individually measured by the dosimeter. Monte Carlo simulation was used to simulate the distances between tools and workers, which were used to determine noise levels in the modeling. The personal measurements of noise exposure were around 80 dBA with peaks locating between 1 and 4 kHz and were fairly matched by the simulated results. This pilot modeling is seemingly feasible and promising, and noise exposure could be assessed by multiple times of tool use with known noise characteristics of the tools. The convenient dose estimates could be useful for the hearing protection of woodworkers.

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Noise of small-scale contra rotating rotors

Journal of Physics Conference Series ◽

10.1088/1742-6596/2061/1/012019 ◽

2021 ◽

Vol 2061 (1) ◽

pp. 012019

Author(s):

I P Boychuk ◽

A V Grinek

Keyword(s):

Experimental Study ◽

Rotor Blade ◽

Filling Factor ◽

Broadband Noise ◽

Small Scale ◽

Noise Levels ◽

Noise Emission ◽

Aerodynamic Loads ◽

Noise Characteristics ◽

Soundproof Chamber

Abstract This article presents the results of an experimental study of the noise characteristics of small-scale coaxial counter-rotating rotors. The tests were carried out in an anechoic soundproof chamber for F7/A7 counter-rotating rotors with 11 and 9 blades on the front and rear rotors, respectively. The intensity of noise emission by rotors was compared with the constancy of the thrust of the power units. Acoustic studies have shown the presence of tonal and broadband noise components at low rotation speeds. In addition to the usual noise components, tonal components were also observed for the rotor blade running combinations. The observed noise levels at these frequencies are equal, and in some directions are significantly higher than the noise levels at the frequencies of the blades of the first and second rows. In experiments, it was found that, while maintaining the equality of the rods, with an increase in the diameter, the noise levels at the rotors decrease due to a decrease in peripheral speeds. A decrease in the noise levels of rotors with an increase in the number of blades was established due to a decrease in aerodynamic loads on the blades and peripheral speeds. An important parameter here is the filling factor of the space swept by the blades. With an increase in this coefficient, the rotation noise decreases, but the vortex noise increases significantly.

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The physical environment

10.1093/oso/9780198827238.003.0003 ◽

2018 ◽

Author(s):

Philip James

Keyword(s):

Physical Environment ◽

Urban Climate ◽

Urban Environments ◽

Artificial Light ◽

Noise Levels ◽

Light At Night ◽

High Noise ◽

P Elements ◽

Micro Organisms ◽

Diversity Of Life

Elements of the physical aspects of urban environments determine which micro-organisms, plants, and animals live in urban environments. In this chapter, climate, air, water, soil, noise, and light are discussed. Urban environments are affected by the climate of the region in which they are located, and in turn and create their own, distinctive urban climate. Air, water, and soil are all affected by urbanization. Pollution of these elements is common. High noise levels and artificial light at night (ALAN—a new phenomenon) are both strongly associated with urban environments. Details of both are discussed. The discussion in this chapter provides a foundation for further exploration of the diversity of life in urban environments and for later exploration of how organisms adapt to urban living, which will be discussed in Parts II and III.

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Improved Vancouver Raman Algorithm Based on Empirical Mode Decomposition for Denoising Biological Samples

Applied Spectroscopy ◽

10.1177/0003702819860121 ◽

2019 ◽

Vol 73 (12) ◽

pp. 1436-1450 ◽

Cited By ~ 1

Author(s):

Fabiola León-Bejarano ◽

Martin O. Méndez ◽

Miguel G. Ramírez-Elías ◽

Alfonso Alba

Keyword(s):

Empirical Mode Decomposition ◽

Raman Spectra ◽

Biological Samples ◽

Biological Material ◽

Noise Levels ◽

Synthetic Material ◽

High Noise ◽

Mode Decomposition ◽

Mean Filter ◽

The Mean

A novel method based on the Vancouver Raman algorithm (VRA) and empirical mode decomposition (EMD) for denoising Raman spectra of biological samples is presented. The VRA is one of the most used methods for denoising Raman spectroscopy and is composed of two main steps: signal filtering and polynomial fitting. However, the signal filtering step consists in a simple mean filter that could eliminate spectrum peaks with small intensities or merge relatively close spectrum peaks into one single peak. Thus, the result is often sensitive to the order of the mean filter, so the user must choose it carefully to obtain the expected result; this introduces subjectivity in the process. To overcome these disadvantages, we propose a new algorithm, namely the modified-VRA (mVRA) with the following improvements: (1) to replace the mean filter step by EMD as an adaptive parameter-free signal processing method; and (2) to automate the selection of polynomial degree. The denoising capabilities of VRA, EMD, and mVRA were compared in Raman spectra of artificial data based on Teflon material, synthetic material obtained from vitamin E and paracetamol, and biological material of human nails and mouse brain. The correlation coefficient (ρ) was used to compare the performance of the methods. For the artificial Raman spectra, the denoised signal obtained by mVRA ([Formula: see text]) outperforms VRA ([Formula: see text]) for moderate to high noise levels whereas mVRA outperformed EMD ([Formula: see text]) for high noise levels. On the other hand, when it comes to modeling the underlying fluorescence signal of the samples (i.e., the baseline trend), the proposed method mVRA showed consistent results ([Formula: see text]. For Raman spectra of synthetic material, good performance of the three methods ([Formula: see text] for VRA, [Formula: see text] for EMD, and [Formula: see text] for mVRA) was obtained. Finally, in the biological material, mVRA and VRA showed similar results ([Formula: see text] for VRA, [Formula: see text] for EMD, and [Formula: see text] for mVRA); however, mVRA retains valuable information corresponding to relevant Raman peaks with small amplitude. Thus, the application of EMD as a filter in the VRA method provides a good alternative for denoising biological Raman spectra, since the information of the Raman peaks is conserved and parameter tuning is not required. Simultaneously, EMD allows the baseline correction to be automated.

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Noise Pollution in Onitsha Metropolis: Challenges and Solution

Open Access Research Journal of Engineering and Technology ◽

10.53022/oarjet.2021.1.2.0110 ◽

2021 ◽

Vol 1 (2) ◽

pp. 032-040

Author(s):

Chris Onyeka Ekweozor ◽

Johnbosco Emeka Umunnakwe ◽

Leo O Osuji ◽

Vincent C Weli

Keyword(s):

State Government ◽

Noise Level ◽

Control Point ◽

Noise Pollution ◽

Health Impact ◽

Dry Season ◽

Noise Levels ◽

Wet Season ◽

High Noise ◽

Anambra State

This study evaluated noise pollution in Onitsha metropolis, Anambra State, Nigeria in 2019. Noise levels were measured at forty sampling stations in the morning, afternoon and night within the study area for dry and wet seasons using modern noise level instruments. A control point was established at ldeani/Nnobi Junction with coordinates N 06o 05’.282’’ E 006o 55’.891’’ which was used as a reference point and for comparison with the sound levels recorded in designated locations. The results showed that the maximum noise level in the study area exceeded the Federal Ministry of Environment (FMEnv) limit by 7.8% in the dry season and by 13.11% in the wet season. Noise LAeq exceeded the NESREA LAeq limit by 29.89% in the dry season and by 33.44% in the wet season. The study indicated that the mean noise levels in the dry and wet seasons were within FMEnv limit of 90dB .It also showed that high noise levels were recorded around major junctions and market places within Onitsha, which are harmful to public health. The study further showed that transportation activities and trading activities at the market places are the main sources of high noise levels in the study area. Health impact assessment should be conducted in Onitsha metropolis for residents. State government should enforce compliance laws and regulate the activities of industries in the areas.

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The sound of potency: An observation study of nurses’ approach to sound in a pediatric intensive care unit

Clinical Nursing Studies ◽

10.5430/cns.v5n2p46 ◽

2017 ◽

Vol 5 (2) ◽

pp. 46

Author(s):

Emma Mellgren ◽

Janet Mattsson

Keyword(s):

Intensive Care Unit ◽

Intensive Care ◽

Pediatric Intensive Care Unit ◽

Pediatric Intensive Care ◽

Well Being ◽

High Tech ◽

Noise Levels ◽

Observation Study ◽

Care Environment ◽

High Noise

Objective: The objective of this study was to investigate the nurses’ approach to three sources of sound that contribute to high noise levels; alarms, doors that open and conversation.Methods: Methods used derived from a theoretical perspective based on interpretive phenomenology and caring culture. In the pediatric intensive care, the caregivers of the children work in a high-tech environment as they are surrounded by sound from several sources. How caregivers understand and acknowledge how these sounds negatively affect a child’s well-being depends on their individual knowledge and awareness of how children are affected by sound. In most cases, coming into an intensive care unit is a new experience for a child. This causes greater stress, both from the environment itself as well as from sound levels. The method was built on a phenomenological perspective and an interpretive non-participation, semi-structured observations were conducted in a pediatric intensive care unit (PICU) of one of Sweden’s metropolitan regions in the winter of 2014-2015.Results: The results show that noise is an overlooked phenomenon in the pediatric intensive care environment as it has given way to other priorities in the nurse’s work. It is also apparent that this depends on the department’s caring culture as it prioritizes other things, resulting in normalizing high levels of noise as a part of the pediatric intensive care environment.Conclusions: Noise levels are not a priority in the department’s caring culture. High noise levels are permitted unreflectedly and appears to be a token of potency and an accepted part of the health care environment.

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