A Study of Air-coupled Ultrasonic Flowmeter Using Beam Focusing

Air-coupled Ultrasonic Testing of Materials

NDE Applications of Air-Coupled Ultrasonic Transducers

Abslract In recent years, several new NDE applications of air-coupled, as opposed to liquid-coupled, ultrasonics have been seriously pursued. The applications range from throughtransmission testing of aerospace laminates and various honeycomb or foam filled materials, and solar cells, to pulseecho flaw detection in plastic electronic packaging materials and in-line inspection of large-diameter ...

Air-Coupled Nondestructive Evaluation Using Micromachined Ultrasonic Transducers

Nondestructive evaluation techniques Amlrurn , which use conventional piezoelectric transducers tvDicallv reauire liquid coupling fluids to improve " _ . the impedance mismatch between piezoelectric materials and air. Air-coupled ultrasonic systems can eliminate this requirement if the dynamic range of the system is large enough such that the losses a t the air-solid interfaces are tolerable. C...

The Development of CPLD-Based Ultrasonic Flowmeter

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 doppler flowmeter-guided occipital nerve block

BACKGROUND Greater occipital nerve block is used in the treatment of headaches and neuralgia in the occipital area. We evaluated the efficacy of ultrasonic doppler flowmeter-guided occipital nerve block in patients experiencing headache in the occipital region in a randomized, prospective, placebo-controlled study. METHODS Twenty-six patients, aged 18 to 70, with headache in the occipital reg...