نتایج جستجو برای: vibration technique

تعداد نتایج: 658072  

Journal: :Journal of biomechanics 2011
S J P M van Engelen A J van der Veen A de Boer M H M Ellenbroek T H Smit B J van Royen J H van Dieën

Structural vibration testing might be a promising method to study the mechanical properties of spinal motion segments as an alternative to imaging and spinal manipulation techniques. Structural vibration testing is a non-destructive measurement technique that measures the response of a system to an applied vibration as a function of frequency, and allows determination of modal parameters such a...

2017
Minghao Pan Yongmin Yang Fengjiao Guan Haifeng Hu Hailong Xu

The accurate monitoring of blade vibration under operating conditions is essential in turbo-machinery testing. Blade tip timing (BTT) is a promising non-contact technique for the measurement of blade vibrations. However, the BTT sampling data are inherently under-sampled and contaminated with several measurement uncertainties. How to recover frequency spectra of blade vibrations though processi...

2007
Vincent Rouillard

Gaussian elements. The hypothesis that random non-stationary vehicle vibrations are essentially composed of a sequence of zero-mean random Gaussian processes of varying standard deviations is tested and the paper reveals that the variations in the magnitude of the vibrations are the cause of the leptokurtic, non-Gaussian nature of the process. It is shown how non-stationary vibration signals ca...

2013
Ming Zhao Jing Lin Xiaoqiang Xu Yaguo Lei

Vibration analysis is an effective tool for the condition monitoring and fault diagnosis of rolling element bearings. Conventional diagnostic methods are based on the stationary assumption, thus they are not applicable to the diagnosis of bearings working under varying speed. This constraint limits the bearing diagnosis to the industrial application significantly. In order to extend the convent...

2010
Zhen Wang Brigitte M Baumann Karen Slutsky Karen N Gruber Smith Jean

BACKGROUND Although congestive heart failure (CHF) patients typically present with abnormal auscultatory findings on lung examination, respiratory sounds are not normally subjected to additional analysis. The aim of this pilot study was to examine respiratory sound patterns of CHF patients using acoustic-based imaging technology. Lung vibration energy was examined during acute exacerbation and ...

Journal: :British journal of industrial medicine 1988
N Olsen O U Petring

The fingers of seven women with primary Raynaud's phenomenon (PRP), 10 female controls, seven men with vibration induced white finger (VWF), and eight male controls were exposed to vibration and the relative change in finger capillary blood flow was measured by an atraumatic 133xenon washout technique without and during proximal nervous blockade. All four groups showed a vasoconstriction to vib...

2014
Yongzhi Qu David He Jae Yoon Brandon Van Hecke Eric Bechhoefer Junda Zhu

In recent years, acoustic emission (AE) sensors and AE-based techniques have been developed and tested for gearbox fault diagnosis. In general, AE-based techniques require much higher sampling rates than vibration analysis-based techniques for gearbox fault diagnosis. Therefore, it is questionable whether an AE-based technique would give a better or at least the same performance as the vibratio...

Analytical solutions are attractive for parametric studies and consideration of the problems physics. In addition, analytical solutions can be employed as a reference framewo...

2005
Ji-Qin Ni Albert J. Heber Teng T. Lim Claude A. Diehl

When measuring emissions of gases, particulate, and odor from animal buildings, the ventilation data are equally important as the concentration data, because emission rate of a pollutant is the product of its concentration and the ventilation rate. However, effectively measuring and monitoring building ventilation remains a technical challenge, especially in barns with numerous fans. Although s...

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