Effect of Rotation on Mechanical Waves Propagation in a Dry Long Bone

The aim of this paper is to present results of an experimental analysis focused on the mechanical waves passing through fine-grained materials, prepared from the CEM I 52.5 R Portland cement and the water coefficient w/c = 0.40, during the setting and hardening phase. In the experiment differences in the wave propagation in cement pastes and mortars were investigated. After mixing, both materials were poured into a cylindrical mould with the diameter of 75.0 ± 0.3 mm. These test specimens were then used to observe, in particular, the development of the amplitude of mechanical waves using a measuring setup which was composed for this purpose from the equipment of the Brno University of Technology. The results show that the time of „critical changes" in the internal structure of the material can be determined. These changes are related to the quality of the bonds of the particles in the internal structure which are reflected in the propagation of the mechanical waves within the material. It is also expected that the experimental analysis will help extend the knowledge of mechanical waves propagation in cement-based composite materials during setting.

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Clutter filter wave imaging: A new way to visualize and detect mechanical waves propagation

2017 IEEE International Ultrasonics Symposium (IUS) ◽

10.1109/ultsym.2017.8092882 ◽

2017 ◽

Author(s):

Sebastien Salles ◽

Lasse Lovstakken ◽

Hans Torp ◽

Svein Arne Aase ◽

Tore Gruner Bjastad

Keyword(s):

Mechanical Waves ◽

Wave Imaging ◽

Waves Propagation

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Analysis of Piezoelectric Sensors in Adulteration of Bovine Milk Using the Chromatic Technique

Proceedings ◽

10.3390/ecsa-5-05728 ◽

2018 ◽

Vol 4 (1) ◽

pp. 38 ◽

Cited By ~ 1

Author(s):

Marcos Messias dos Santos Junior ◽

José Alfredo Covolan Ulson ◽

Bruno Albuquerque de Castro ◽

Jorge Alfredo Ardila-Rey ◽

Fernando de Souza Campos ◽

...

Keyword(s):

Quality Control ◽

Sodium Hydroxide ◽

Food Industry ◽

Low Cost ◽

Bovine Milk ◽

Response Signal ◽

Mechanical Waves ◽

Milk Adulteration ◽

Waves Propagation ◽

Energy Average

Sensors applied in the food industry are important tools for quality control. Current analyses checking adulteration in milk are expensive and time consuming, because the samples need to be evaluated in a laboratory environment. Thus, is important to develop methodologies and sensors to monitor milk production. A common type of fraud is performed adding substances such as sodium hydroxide in order to increase the shelf life of milk. In this study, we propose to use low-cost piezoelectric diaphragms transducers to implement a methodology that identifies milk adulteration using the mechanical waves propagation method (vibration and acoustic emission). Two piezoelectric diaphragms were used, the first was excited by a chirp signal with 1 V of amplitude and a frequency band since 0 to 65 kHz with 2 Hz of step, and concomitantly acquired the response signal of the second sensor installed in the opposite side of the actuator with a rate of 250 kHz. After acquiring the data, these were processed using the chromatic technique, which extracts three features: energy, average band and equivalent bandwidth, in order to classify the raw and the contaminated milk through clustering. The experimental results indicated that the methodology can differentiate between raw and contaminated milk with 1% of sodium hydroxide. Therefore, the results reported in this study indicate that low-cost piezoelectric diaphragms are promising for liquids quality control.

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