نتایج جستجو برای: vibration and noise

تعداد نتایج: 16868234  

2014
Kang Seok Seo Sun Kim

In this study, the vibration and noise for the cushion frame that directly contacts the driver of the car are investigated. The friction noise from the seat track generating the largest noise is measured and analyzed. Also, vibration measurement and analysis are performed in parallel to locate the position from where the noise is generated. In the next stage, the RPM of motor and the current ch...

2017
Cory Nelson

In the radio communications industry, one major problem is the vibration induced on to a frequency standard. The most commonly used frequency standard is the crystal oscillator; as the crystal oscillator gets vibrated with varying force and frequencies of vibration the phase noise of the signal changes. As the phase noise increases, the signal to noise ratio decreases causing the likelihood of ...

Journal: :Journal of Zhejiang University 2021

2017
Jihyun Kim Wanhyung Lee Jong-Uk Won Jin-Ha Yoon Hongdeok Seok Yeong-Kwang Kim Seunghyun Lee Jaehoon Roh

INTRODUCTION The individual and combined effect of occupational noise and vibration exposures, on workers' health has not been thoroughly investigated. In order to find better ways to prevent and manage workers' headache, this study aimed to investigate the effects of occupational noise and vibration exposure on headache/eyestrain. METHODS We used data from the fourth Korean Working Condition...

Journal: :health scope 0
sahand ghafori department of occupational health, faculty of medical sciences, tarbiat modares university, tehran, ir iran ali khavanin department of occupational health, faculty of medical sciences, tarbiat modares university, tehran, ir iran; department of occupational health, faculty of medical sciences, tarbiat modares university, tehran, ir iran. tel: +98-2182883564 hassan assilean department of occupational health, faculty of medical sciences, tarbiat modares university, tehran, ir iran ardalan solimanian department of occupational health, faculty of medical sciences, tarbiat modares university, tehran, ir iran

conclusions use of flexible joint in the exhaust system leads to conversion of linear vibration to non-linear one, resulting in significant reduction of noise levels. results by using this new exhaust at speed levels of 1000, 2000, 3000, 4000, and 5000 rpm, we had respectively 3.9, 6.8, 7.4, 5.6, and 5 dba decreases in total sound level pressure. objectives this study aimed to reduce motorcycle...

Journal: :iranian journal of fuzzy systems 2012
s. r. mousavi-aghdam m. b. b. sharifian m. r. banaei

this paper presents a new control structure to reduce torque ripple in switched reluctance motor. although srm possesses many advantages in motor structure, it suers from large torque ripple that causes some problems such as vibration and acoustic noise. in this paper another control loop is added and torque ripple is de ned as an objective function. by using fuzzy sliding mode strategy, the dc...

2017
S. Abdi D. X. Llano E. Abdi R. A. McMahon

In this work, a large-scale Brushless Doubly Fed Machine (BDFM) built in frame size D400 is tested at different operating conditions in order to examine its noise and vibration levels. A series of measurements were conducted on the machine to establish the main modes of excitation of vibration and noise developed by the machine. The harmonic spectrums of the vibration amplitudes are presented a...

Journal: :advances in railway engineering,an international journal 2015
morteza esmaeili seyed ali mosayebi farhad kooban

the evaluation and control of the trains induced vibrations needs even more attention in the case of underground tracks which passes near to monuments and historical sites. the rail corrugations which occur due to the wheels’ impulse loads during the operation period of underground railway tracks, usually amplify the ground borne noise and vibration. in the current study, the mentioned phenomen...

2009
Mats Åkerblom

This paper is a survey of the literature on gear noise and vibration. It is divided into three parts, “Transmission error”, “Dynamic models” and “Noise and vibration measurement”. Transmission error (TE) is considered to be an important excitation mechanism for gear noise and vibration. The definition of transmission error is “The difference between the actual position of the output gear and th...

2011
Zbigniew Koziel Eulalia Peris James Woodcock Gennaro Sica Andrew T. Moorhouse David C. Waddington

The DEFRA funded project “Human Response to Vibration in Residential Environments” investigates relationships between human response in residential areas, primarily in terms of annoyance, and combined effects from exposure to vibration and noise. This paper focuses on the results from the analysis of noise exposure in this study, in particular from construction work and railway traffic. The exp...

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