During the last three years the Swedish Institute for Metals Research (SIMR) has done extensive work on applications of laser generated ultrasound (LUS). This paper reports results from several experiments mainly aimed at industrial on-line applications. LUS has been used to determine grain sizes in commercial low-carbon (LC) and stainless steels. The analysis method employs a scattering theory...

We present here a new ultrasonic diagnosis technique in natural, porous rocks. This method, based on the ultrasonic velocity changes, allows us to measure the transient spacial distribution of two liquids (water and oil) in a sandstone.

Time-Delay-Estimation (TDE) has been a topic of interest in many applications in the past few decades. The emphasis of this work is on the application of model-based estimation (MBE) for TDE of ultrasonic signals used in ultrasonic thickness gaging. Ultrasonic thickness gaging is based on precise measurement of the time difference between successive echoes which reflect back from the back wall ...

HIFU power measurement At ultrasonic laboratory of INRIM (Istituto Nazionale di Ricerca Metrologica) it is possible to measure the ultrasonic power emitted by HIFU (High Intesity Focused Ultrasound) transducers. Two different measuring systems for the determination of ultrasonic power have been developed. Both systems are based on the radiation force balance method. The first system is based on...

Ultrasonic distance measurement using the pulse-echo method is based on the determination of the time of flight of ultrasonic waves. The pulse-compression technique, in which the cross-correlation function of a detected ultrasonic wave and a transmitted ultrasonic wave is obtained, is the conventional method used for improving the resolution of distance measurement. However, the calculation of ...

Specific volume and ultrasonic velocity measurements have been carried out on the liquid crystal N-(p-n-hexyloxybenzylidene)-p-n-butylaniline in the isotropic, nematic, smectic A, smectic B and smectic G phases. The variation of the specific volume with temperature shows that the corresponding transitions are of first order. Thermal expansion coefficients have been calculated for all the mesoph...

This paper proposes a new detection system for monitoring gas concentration and flow rate. Velocity difference of ultrasonic wave in bi-directional propagation in measured gas is recorded and utilized for computing the online gas concentration and flow rate. Meanwhile, the temperature compensation, return signal processing and error analysis algorithms are applied to improve the accuracy. The e...

The nondestructive determination of the maturity of durian is an important process for quality control. Since durian has specific properties, such as the thickness of peel, non-uniformity of shape, roughness of prickle skin, largeness of size etc., the nondestructive determination of the maturity is hard to perform. This paper proposes two approaches for determining maturity of durian by using ...

The problems of the development of high-temperature radiation resistant ultrasonic sensors operating in a liquid lead-bismuth alloy are analysed. Experimental diffusion bonded bismuth titanate sensors for operation up to 450 °C were developed. For acoustical coupling with a liquid metal the sensor protector is polished or coated by a diamond like carbon layer. The developed sensors survived hig...