A New Ultrasound Pulser Technique for Wide Range Measurements

IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 2000

The ongoing expansion of the frequency range used for ultrasonic imaging requires increasing attention to the acoustic attenuation of biomaterials. This work presents a novel method for measuring the attenuation of tissue and liquids in vitro on the basis of single transmission measurements. Ultrasound was generated by short laser pulses directed onto a silicon wafer. In addition, unfocused piezoelectric transducers with a center frequency of 50 MHz were used to detect and emit ultrasound. The laser ultrasound method produces signals with a peak frequency of 30 MHz. In comparison to piezoelectric generation, pulse laser excitation provides approximately 4 times higher amplitudes and 20% larger bandwidth. By using two excitation methods in succession, the attenuation parameters of porcine fat samples with thicknesses in the range of 1.5 to 20 mm could be determined quantitatively within a total frequency range of 5 to 45 MHz. The setup for liquid measurements was tested on samples of human blood and olive oil. Our results are in good agreement with reports in literature.

Food Research International, 2004

The food industry can benefit from a highly sensitive, non-invasive, self-calibrating, on-line sensor for characterizing liquid or slurry in process vessels during mixing, settling, stationary, or flowing conditions by measuring the reflections at the fluid-sensor interface, sound speed, and attenuation of ultrasound to determine the fluid density and solids concentration. The sensor system was developed by staff at Pacific Northwest National Laboratory. The sensor transducers are mounted directly on the stainless steel wall and the pipeline wall becomes part of the measurement system. Multiple reflections within the stainless steel wall are used to determine the acoustic impedance of the liquid, where the acoustic impedance is defined as the product of the density and the speed of sound. The probe becomes self-calibrating because variations in the pulser voltage do not affect the measurements. By basing the measurement upon multiple reflections, the sensitivity of the measurement is significantly increased.

Nonintrusive Inspection, Structures Monitoring, and Smart Systems for Homeland Security, 2006

Government agencies and homeland security related organizations have identified the need to develop and establish a wide range of unprecedented capabilities for providing scientific and technical forensic services to investigations involving hazardous chemical, biological, and radiological materials, including extremely dangerous chemical and biological warfare agents. Pacific Northwest National Laboratory (PNNL) has developed a prototype portable, handheld, hazardous materials acoustic inspection prototype that provides noninvasive container interrogation and material identification capabilities using nondestructive ultrasonic velocity and attenuation measurements. Due to the wide variety of fluids as well as container sizes and materials encountered in various law enforcement inspection activities, the need for high measurement sensitivity and advanced ultrasonic measurement techniques were identified. The prototype was developed using a versatile electronics platform, advanced ultrasonic wave propagation methods, and advanced signal processing techniques. This paper primarily focuses on the ultrasonic measurement methods and signal processing techniques incorporated into the prototype. High bandwidth ultrasonic transducers combined with an advanced pulse compression technique allowed researchers to 1) obtain high signal-to-noise ratios and 2) obtain accurate and consistent time-of-flight (TOF) measurements through a variety of highly attenuative containers and fluid media. Results of work conducted in the laboratory have demonstrated that the prototype experimental measurement technique also provided information regarding container properties, which will be utilized in future container-independent measurements of hidden liquids.

The Journal of the Acoustical Society of America, 1995

This paper presents two methods to measure the density of liquids based on the measurement of the reflection coefficient and propagation velocity, using a novel double-element transducer. The measurements can be made in liquids, stationary or in motion. The main factors that affect the precision of the measurements are analyzed. The effect of acoustic diffraction is eliminated by using the double-element transducer, where the receiver is somewhat larger in diameter than the emitter. The effect of short-and long-term stability of the electronics and piezoelectric ceramics employed in the system is also eliminated. A system was implemented and measurements of several liquids, stationary and in motion, were conducted.

MAPAN, 2020

Ultrasonic velocity is an important property for various physicochemical investigations in the liquids. The continuous wave ultrasonic interferometers are widely used as a cost-effective instrument for the estimation of ultrasonic propagation velocity. One of the critical aspects of this instrument is the level of radio frequency excitation supplied to piezoelectric transducer, which can cause heating of the sample. The error in the ultrasonic velocity measurement due to heating by the ultrasonic interferometer is described. In this article, the distilled water was used as experimental liquid to study the heating effect. Firstly, the ultrasonic transducer has been used to generate ultrasound in the sample and was calibrated for its radiation conductance by using primary radiation force balance facility of the laboratory. Primary calibration of the ultrasonic transducer in a commercially available system used in the liquid cell showed 68 mW power for excitation level. In a laboratory interferometer designed for low-power operation in the same test cell, the measured power was only 85 lW. In order to study the heating effect, the ultrasonic velocity was measured with both the systems without controlling the temperature of liquid cell. The measurements by commercial system showed significant deviation (5.6 ms-1) in ultrasonic velocity as compared to that measured under low power excitation, which remains almost undeviated. The Marczak equation was used to calculate the deviation in velocity due to ultrasound heating.

Proceedings of the 20th IEEE Instrumentation Technology Conference (Cat. No.03CH37412), 2003

Rapid, on-line determination of particle size and concentration is required for the efficient process measurement and control of many processes in government and industrial applications such as waste remediation for the Department of Energy sites and process control for chemical and pharmaceutical manufacturing. However, existing methods based on ultrasonic attenuation can become inaccurate for highly concentrated suspensions due to careful transducer alignment and the complicated mathematics required to describe multiple scattering, which controls the attenuation. Two measurements that help to overcome these difficulties are the ultrasonic backscattering and diffuse field. Backscattering is attractive because the single scattering theories typically used to describe backscattering are mathematically simpler than attenuation theories and lend themselves to more stable inversion processes. Also, the measurements of backscattering and diffuse fields do not require long travel distances and can be made with a single transducer thus eliminating alignment problems. We will present ultrasonic measurements on solid liquid suspensions designed to elucidate the particle size and concentration at high concentrations.

Ultrasonics, 1991

Experimental measurements have been made of the ultrasonic velocity and attenuation in some simple suspensions of, mainly, silicon carbide in water and in ethylene glycol. These are compared with theoretical predictions based on a novel hydrodynamic model. Predicted ultrasonic velocities are in excellent agreement with the measured values. Predicted and measured ultrasonic attenuations do not agree as well. However, the suspensions give rise to excess attenuations rising to a few hundred nepers per metre and special experimental techniques were needed to measure ultrasonic properties. To predict attenuations to within, say, 20% for mixtures such as these is a major achievement.

In oil industry, sand content in crude oils is commonly used as a parameter to determine the well deterioration level and to assess horizontal wells collapse risk. The sand content measurement is usually performed by a sand content meter device, which is based on a sieves system. This device requires a human operator to collect and analyze the crude oil samples. In order to allow a real time sand content monitoring in crude oil, this work presents a new ultrasonic technique to determine solid particle concentration in liquids. This technique consists in emitting an ultrasonic wave by an ultrasonic transducer and measuring the backscattered ultrasonic signals produced by sand particles. Therefore, the objective of this work is to develop a measurement cell based on the ultrasonic waves scattering to estimate the sand particles concentration in crude oil. The experimental observations were made with a measuring cell built for laboratory batch testing and continuous solid particles flow. Ultrasound transducers with central frequencies ranging from 5 and 10 M Hz in pulse-echo mode were used. Laboratory batch tests using sand particles ranging in size from 100 to 500 µm in diameter shown that there is a linear relationship between the volumetric fraction of particle and ultrasonic backscattered energy. The backscattered energy is proportional to the squared voltage measured from the receiving transducer. The echo signal mean energy at a given time window corresponds to the instantaneous flowing sand content through the cell. A micro-controlled feeder device was developed to perform tests on continuous solid particles flow. An analytical balance was used to calibrate the feeder to operate in the range from 2 to 20 mg/s, producing a water mixture ranging from 200 to 2000 ppm. Tests with continuous flow are in agreement with the expected results from the adopted methodology. A backscattered energy computational model based on a transducer impulse response and a plane piston model was developed to understand the experimental results. This model predicts the linear relationship between the backscattered energy and the particle concentration observed experimentally. The results demonstrate the technical feasibility of continuous flow measurements of sand in oil.

2004

Rapid, on-line determination of particle size and concentration is required for the efficient process measurement and control of many processes in government and industrial applications such as waste remediation for the Department of Energy sites and process control for chemical and pharmaceutical manufacturing. However, existing methods based on ultrasonic attenuation can become inaccurate for highly concentrated suspensions due to careful transducer alignment and the complicated mathematics required to describe multiple scattering, which controls the attenuation. Two measurements that help to overcome these difficulties are the ultrasonic backscattering and diffuse field. Backscattering is attractive because the single scattering theories typically used to describe backscattering are mathematically simpler than attenuation theories and lend themselves to more stable inversion processes. Also, the measurements of backscattering and diffuse fields do not require long travel distances and can be made with a single transducer thus eliminating alignment problems. We will present ultrasonic measurements on solid liquid suspensions designed to elucidate the particle size and concentration at high concentrations.

Water Science & Technology, 2009

In the frame of a technological research and innovation network in water and environment technologies (RITEAU, Réseau de Recherche et d'Innovation Technologique Eau et Environnement), our research group, in collaboration with industrial partners and other research institutions, has been in charge of the development of a suitable flowmeter: an ultrasonic device measuring simultaneously the water flow and the concentration of size classes of suspended particles. Working on the pulsed ultrasound principle, our multi-frequency device (1 to 14 MHz) allows flow velocity and water height measurement and estimation of suspended solids concentration. Velocity measurements rely on the coherent Doppler principle. A self developed frequency estimator, so called Spectral Identification method, was used and compared to the classical Pulse-Pair method. Several measurements campaigns on one wastewater collector of the French city of Strasbourg gave very satisfactory results and showed smaller s...

Proceedings of Spie the International Society For Optical Engineering, 2006

Government agencies and homeland security related organizations have identified the need to develop and establish a wide range of unprecedented capabilities for providing scientific and technical forensic services to investigations involving hazardous chemical, biological, and radiological materials, including extremely dangerous chemical and biological warfare agents. Pacific Northwest National Laboratory (PNNL) has developed a prototype portable, handheld, hazardous materials acoustic inspection prototype that provides noninvasive container interrogation and material identification capabilities using nondestructive ultrasonic velocity and attenuation measurements. Due to the wide variety of fluids as well as container sizes and materials encountered in various law enforcement inspection activities, the need for high measurement sensitivity and advanced ultrasonic measurement techniques were identified. The prototype was developed using a versatile electronics platform, advanced ultrasonic wave propagation methods, and advanced signal processing techniques. This paper primarily focuses on the ultrasonic measurement methods and signal processing techniques incorporated into the prototype. High bandwidth ultrasonic transducers combined with an advanced pulse compression technique allowed researchers to 1) obtain high signal-to-noise ratios and 2) obtain accurate and consistent time-of-flight (TOF) measurements through a variety of highly attenuative containers and fluid media. Results of work conducted in the laboratory have demonstrated that the prototype experimental measurement technique also provided information regarding container properties, which will be utilized in future container-independent measurements of hidden liquids.

The Journal of Chemical Physics, 1946

The Chemical Engineering Journal and the Biochemical Engineering Journal, 1995

An ultrasomc technique was developed to measure the concentration of sohds m a three-phase slurry reactor Prehrnmary measurements were taken on slumes conslstmg of water, glass beads, and nitrogen bubbles The data show that the speed and attenuation of the sound are well defined functions of the solid and gas concentrahons m the slumes A simple model IS proposed to correlate the concentration of solids with the measured charactenstlcs of the ultrasonic signals

Journal of Food Engineering, 1988

The basic ideas underlying the use of ultrasound in non-destructive testing are reviewed with a special emphasis on their relevance to food engineering. Sound velocity is a valuable engineering tool because of its relative ease of measurement, ease of interpretation of the consequent data and its greater accuracy than attenuation measurements. It is a non-destructive, non-invasive, non-intrusive technique. Low-intensity applications are reviewed and their potential in the measurement of physical properties is emphasised. Such measurements include the determination of adiabatic compressibility, rigidity and, in two-phase systems, particle size and dispersed-_vhase volume fraction. Experimental techniques which the authors have found useful for measurements in food systems are described and the accuracy of available techniques is compared.

J Food Process Technol, 2011