Abstrac t This paper presents a procedure for wind speed measurement using ultrasonic transducers based on short-time Fourier transform (STFT). The measurement of wind speed was performed by estimating the ultrasonic transit-time (ToF). For this purpose the estimated ToF was used the technique of digital signal processing, based on the STFT. The ultrasonic signal detection was performed by sett...

In ultrasonic nondestructive evaluation (NDE) of materials, pulse echo measurements are masked by the characteristics of the measuring instruments, the propagation paths taken by the ultrasonic pulses, and are corrupted by additive noise. Deconvolution operation seeks to undo these masking effects and extract the defect impulse response which is essential for identification. In this contributio...

In this study a novel servo speed control system for travelling-wave ultrasonic motor (TWUSM) has been presented. A drive system has been built based on two-phase high-frequency inverter using mechanical resonant frequency of the ultrasonic motor. The TMS320F243 digital signal processor (DSP) is adapted to ultrasonic motor drive system. The speed control of ultrasonic motor has been implemented...

The measurement principle of the transit time difference method of the ultrasonic flowmeter is presented. The hardware structure and realization method are introduced. The software function and work mode are overviewed. In order to enhancing flowmeter's precision and stability a Xilinx CoolRunner CPLD and a Texas Instruments microcontroller from MSP430 family are applied in high precision timin...

Ultrasonic measurement techniques can be used to determine some characteristics of turbulent flows. In this work measurements of the difference in propagation times of ultrasonic waves along two paths are combined with the Kolmogorov (j )-power law to study characteristics of grid-generated turbulence. The paper focuses on ultrasonic measurements of turbulent flow using the travel-time techniqu...

The ultrasonic absorption of sickle cells was compared with the morphological changes in these cells are produced by varying oxygen tensions and pH. A decrease in oxygen tension caused increased sickling and an increase in the ultrasonic absorption of the blood. An increase in pH reduced the ultrasonic absorption and decreased sickling. These findings indicate that ultrasonic absorption can det...

PURPOSE To compare the performance of sonic phacoemulsification with that of ultrasonic phacoemulsification in regard to 1-day postoperative visual acuity, corneal edema, and procedure efficiency. SETTING Oregon Eye Institute, Eugene, Oregon, USA. METHODS This prospective nonrandomized study comprised 86 eyes with mild to moderate nuclear sclerotic cataract. Forty-three eyes had sonic and 4...

PURPOSE The purpose of this case-control study was to determine whether long-term ultrasonic noise exposure via the dental office environment is related to dental hygienists' hearing status. METHODS Registered dental hygienists (N = 698) who live in the Hampton Roads areas of Virginia were mailed a Dental Hygiene Work History Questionnaire to determine who would meet the inclusion criteria an...

This paper describes the investigation for the feasibility of inspection of steel-rocasin rubber specimen used in rocket motor for detection of debond by using air-coupled ultrasonic. A pair of high performance air-coupled transducers was used to generate and receive the high intensity ultrasonic pulses. Probes were placed at the opposite side of the specimen during inspection. It was shown tha...