Analysis of laser generated ultrasonic wave frequency characteristics induced by a partially closed surface-breaking crack

2013 ◽  
Vol 52 (18) ◽  
pp. 4179 ◽  
Author(s):  
Jia Li ◽  
Hongchao Zhang ◽  
Chenyin Ni ◽  
Zhonghua Shen
Keyword(s):  
Ultrasonic Wave ◽  
Closed Surface ◽  
Frequency Characteristics ◽  
Wave Frequency ◽  
Surface Breaking Crack

scholarly journals Alpha-wave frequency characteristics in health and insomnia during sleep

2016 ◽  
Vol 25 (3) ◽  
pp. 278-286 ◽  
Author(s):  
Justus T. C. Schwabedal ◽  
Maik Riedl ◽  
Thomas Penzel ◽  
Niels Wessel
Keyword(s):  
Frequency Characteristics ◽  
Wave Frequency ◽  
Alpha Wave

Experimental Investigation for Characteristics of Localized Dissolution of Micro-Holes in Electrochemical Machining Aided by Ultrasonic Wave

2013 ◽  
Vol 567 ◽  
pp. 21-26 ◽  
Author(s):  
Zhi Yong Li ◽  
Zong Wei Niu ◽  
Li Li
Keyword(s):  
Experimental Investigation ◽  
Ultrasonic Wave ◽  
Electrochemical Machining ◽  
Wave Frequency ◽  
Micro Machining ◽  
Micro Holes ◽  
Micro Hole ◽  
Set Up

Electrochemical micro-machining (EMM) has become one of the main machining methods for production of miniaturized parts and components. Utilizing the developed EMM set-up, the effects of ultrasonic wave frequency on characteristics of localized dissolution and accuracy of micro-hole in EMM are investigated and evaluated. The experiment results demonstrate that the accuracy of micro-hole and characteristics of localized dissolution can become better with the increase of ultrasonic wave frequency. The accuracy of micro-hole machined by 26KHZ can improve about 30% than that by 16KHZ. Moreover, the ability of localized dissolution by 26KHZ can be increased about 27%-30%.

scholarly journals SINTESIS BIODISEL MELALUI ESTERIFIKASI DAN TRANSESTERIFIKASI MINYAK NYAMPLUNG TEROZONISASI DENGAN BANTUAN GELOMBANG ULTRASONIK

2017 ◽  
Vol 22 (1) ◽  
pp. 1
Author(s):  
Haryono ◽  
E. Evy Ernawati ◽  
Rukiah ◽  
Susi Suryani
Keyword(s):  
Iodine Number ◽  
Ultrasonic Wave ◽  
Acid Value ◽  
Ultrasonic Waves ◽  
Flash Point ◽  
Transesterification Reaction ◽  
Wave Frequency ◽  
Esterification Reaction ◽  
Frequency Variation ◽  
Biodiesel Synthesis

Tujuan penelitian ini adalah mensintesis biodiesel dari minyak nyamplung melalui proses esterifikasi dan transesterifikasi dengan bantuan ozonisasi dan gelombang ultrasonik. Ozonisasi dilakukan selama 30 menit, sedangkan reaksi transesterifikasi dibantu dengan gelombang ultrasonik pada variasi frekuensi 28 dan 35 kHz masing-masing selama 30 menit. Hasil penelitian menunjukkan bahwa penggunaan gelombang ultrasonik dengan frekuensi 35 kHz pada reaksi transesterifikasi terhadap minyak nyamplung terozonisasi dari reaksi esterifikasi dihasilkan biodiesel yang relatif sesuai dengan standar biodiesel Indonesia. Biodiesel yang dihasilkan pada kondisi tersebut memiliki bilangan asam 0,70 mgKOH/g biodiesel, bilangan iodium 50,34 g I2/100 g, titik nyala 122,4°C, bilangan cetana 102,5, densitas 0,9088 g/cm3, dan viskositas 9,5 cSt.(BIODIESEL SYNTHESIS THROUGH NYAMPLUNG OIL ESTERIFICATION AND TRANSESTERIFICATION USING ULTRASONIC WAVES ASSIST)This study was aimed at synthesizing biodiesel of nyamplung oil through esterification and transesterification process using ozonation and ultrasonic waves assist. The ozonation was done for 30 minutes, while the transesterification reaction was aided by ultrasonic wave frequency variation 28 and 35 kHz for 30 minutes. The results show that the use of ultrasonic waves in frequency of 35 kHz in the transesterification reaction to the ozonized nyamplung oil from esterification reaction produced biodiesel on the standards of Indonesian biodiesel. The biodiesel product in this study has 0.70 mgKOH/g biodiesel acid value, iodine number 50.34 g I2/100 g, the flash point of 122.4°C, cetana numbers of 102.5, density of 0.9088 g/cm3, and a viscosity of 9.5 cSt

scholarly journals Investigation of alpha-wave frequency characteristics in the patients with chronic tension headache and its modification during electromyographic-temperature training

2010 ◽  
Vol 9 (2) ◽  
pp. 42-46 ◽  
Author(s):  
O. S. Shubina ◽  
M. Ye. Melnikov ◽  
I. A. Veretelnikov
Keyword(s):  
Tension Headache ◽  
Frequency Characteristics ◽  
Wave Frequency ◽  
Wave Power ◽  
Alpha Wave ◽  
Temperature Training ◽  
Frequency Power

Chronic tension headache is the most commonly experienced headache. Low effectiveness of its treatment is connected with lack of understanding of this disorder pathogenensis. It was shown that electromyographic-temperature training provoked modification of alpha-wave power and frequency: power of alpha increased, frequency of maximal increased as well.

Characterization of Grains Size by Ultrasounds

2011 ◽  
Vol 482 ◽  
pp. 49-56 ◽  
Author(s):  
Ali Badidi Bouda ◽  
Mohammed S. Aljohani ◽  
Ahmed Mebtouche ◽  
Rafik Halimi ◽  
Wahiba Djerir
Keyword(s):  
Grain Size ◽  
Frequency Shift ◽  
Ultrasonic Wave ◽  
Heat Treatments ◽  
Ultrasonic Waves ◽  
Wave Frequency ◽  
Shift Measurement ◽  
Grain Sizes ◽  
Average Grain Size ◽  
Material Grain Size

A mechanical or thermal treatment of a material can change, among other things, the average grains size. It depends on temperature, holding time, cooling condition or rolling stress. The average grain size, as well as its influence on the propagation velocity and attenuation coefficient of ultrasonic waves, also affects the wave frequency propagating through the material. Grain size is an indicator of material fatigue. It can therefore be used in monitoring or fatigue damage prevention. In this paper, we study the effect of various heat treatments hence different steel average grain sizes on the ultrasonic wave frequency after crossing the material. We have performed the same experimental study on aluminum samples. The different grain sizes are obtained by rolling. The frequency shift measurement of longitudinal waves is achieved by immersion with two probes of different frequencies 2.25 and 5 MHz. The experimental results are shown as curves giving the frequencies depending on the grain size. Heat treatments on steel and aluminum rolling performed on the samples have yielded a grain sizes gradient. Our results are consistent with the theory because of the important path in the sample and in this case the down shift frequency is paramount. They show a direct relationship between the frequency shift and the average grain size. It is therefore possible to trace quantitatively to an average grains size from the frequency of an ultrasonic wave that has passed through this material and hence its thermal or mechanical fatigue state.

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