Ultrasound Pulse-echo Technique Research Articles

Ultrasound pulse-echo measurements in a large-volume press at the High-Pressure Collaborative Access Team (HPCAT)

The large-volume press at beamline 16-BM-B, at the High-Pressure Collaborative Access Team (HPCAT) facility at the Advanced Photon Source (APS), Argonne National Laboratory, offers a comprehensive platform for in-situ characterization of materials' atomic structure and bulk properties under high pressure and/or high-temperature (HP-T) conditions. The beamline is equipped with a Paris-Edinburgh type press with in-situ X-ray, electrical, optical, and ultrasound probes. The ultrasound pulse-echo technique, in conjunction with other techniques, such as energy-dispersive X-ray diffraction, X-ray radiography, and thermal/electric measurements, provides relevant data on material properties, including elastic constants, equation of state, and phase transitions, at HP-T conditions. The beamline is currently undergoing a major redesign to coincide with the APS upgrade. Among other developments, the ultrasound measurements at the upgraded beamline will be optimized with the addition of rotational X-ray tomography, as well as new capabilities for online data analysis. These advancements, together with the improved beamline optics, will improve accuracy and significantly reduce the time needed for data collection, allowing for faster experiments and higher throughput. The presentation will provide an overview of beamline 16-BM-B with a specific focus on acoustic measurements using the ultrasound pulse-echo technique and relevant applications. The beamline's expanded capabilities and scientific examples will be presented.

SonicPy: a suite of programs for ultrasound pulse-echo data acquisition and analysis

ABSTRACT Sound speed and elastic constants measurements in solids and liquids are commonly performed using the ultrasound pulse-echo technique. Recent advances have expanded the use of this technique at numerous high pressure synchrotron beamlines and offline laboratories. However, the increased experimental throughput has revealed many limitations in existing software for handling the rapid measurement and the subsequent data-reduction. We report the development of a collection of computer programs for sound speed measurements using the ultrasound pulse-echo technique, compatible with stepped multi-frequency, as well as broadband-pulse, couplant-corrected methods. The programs provide a highly interactive graphical interface, enable efficient measurement, exploration and near real-time analysis of the ultrasound data, and contain features useful for working with samples under high pressure and/or high temperature. The included analysis programs can alleviate the time required for data reduction from hours to less than a minute, allowing users to make timely and informed decisions regarding the appropriate experimental parameters.

High-frequency ultrasound-based thickness measurement of highly attenuating materials

This paper investigates an effective method for measuring the thickness of highly attenuating materials using the acoustic radiation-induced quasi-static component (QSC) of a primary longitudinal wave (PLW) at high frequency. The generated QSC features lower attenuation than the high-frequency PLW, so the generated QSC pulse with zero carrier frequency can propagate a longer distance at the same group velocity, even in highly attenuating materials. In addition, the method based on the QSC of a high-frequency PLW has better directivity than the low-frequency PLW-based method, making it more suitable for highly attenuated material local thickness measurement. The thickness of highly attenuating materials can be accurately measured by measuring the pulse-echo time-of-flight of the generated QSC pulse using an ultrasound pulse-echo technique. The experimental examinations conducted for highly attenuating silicone rubber blocks with different thicknesses demonstrate that their thicknesses can be accurately measured with the QSC-based method. This paper provides an effective method for thickness measurements of highly attenuating materials.

Ultrasound-Based Smart Corrosion Monitoring System for Offshore Wind Turbines

The ultrasound technique is a well-known non-destructive and efficient testing method for on-line corrosion monitoring. Wall thickness loss rate is the major parameter that defines the corrosion process in this approach. This paper presents a smart corrosion monitoring system for offshore wind turbines based on the ultrasound pulse-echo technique. The solution is first developed as an ultrasound testbed with the aim of upgrading it into a low-cost and low-power miniaturized system to be deployed inside offshore wind turbines. This paper discusses different important stages of the presented monitoring system as design methodology, the precision of the measurements, and system performance verification. The obtained results during the testing of a variety of samples show meaningful information about the thickness loss due to corrosion. Furthermore, the developed system allows us to measure the Time-of-Flight (ToF) with high precision on steel samples of different thicknesses and on coated steel samples using the offshore standard coating NORSOK 7A.

Monitoring early age behavior of mortar by ultrasound technique for environmental issues: Effects of sand grading and salinity of mixing water

This paper aims to study the effects of different sand grading and salinity of mixing water on setting and hardening of cement mortar. For this purpose, a newly developed measurement method based on ultrasound pulse echo technique was used. Using this method, the attenuation coefficient and the modulus of reflection coefficient are measured to characterize the early age behavior of tested mortars. Ultrasound P-waves were generated using a 1 MHz central frequency immersion transducer and mortar samples were prepared with Portland composite cement CPJ 45. Mortar samples were classified into two series: first series considered mortar mixes prepared using fresh water and different sand grading form 56μm to 400μm. These laboratory tests (series 1) aimed to obtain the optimum grain size of respective mortar mixes in terms of optimum workability and rheology. Continually, the optimum grain size (from series 1) is used in the second series of experiments (series 2) mortar mixes prepared using artificial sea water with different concentrations of sea salt, i.e., 0 g/l, 10 g/l, 20 g/l, 37 g/l and 50 g/l. The results show that the increase of sand size grading in mortar allows faster setting and hardening and earlier occurrence of aluminate hydrates phase transition AFt – AFm, precipitates the solid percolation and achieves denser microstructure. Also, the stepwise increase of Sea Salt dosage in mixing water from 0 g/l to 37 g/l resulted in a later achieve of final set and later occurrence of AFt – AFm transition.

Acoustic and mechanical characterization of gelatin methacryloyl scaffolds for tissue engineering applications

Gelatin methacryloyl (GelMA) is a highly biocompatible, biodegradable material and a 3-D printable option for constructing tissue engineering scaffolds. Improved material characterization of GelMA is necessary to optimize preparation techniques, evaluate tissue similarities, and validate tissue engineering potential. Conventional testing methods are through destructive, one-time measurements, yet nondestructive tests are desired for evaluating long-term changes. In the present study, ultrasound techniques were utilized to measure mechanical properties of GelMA tissue scaffolds. Varying concentrations of GelMA and ultraviolet light curing time produced scaffolds with a range of material properties. Ultrasound pulse-echo techniques were used for a non-destructive acoustic characterization procedure, and parameters including speed of sound, acoustic impedance, and attenuation coefficient were measured. To further evaluate the material properties of the scaffolds, compression testing was performed. Physical parameters of GelMA were found to be similar to those of native tissues, demonstrating that GelMA scaffolds are biomimetic. The impact of GelMA concentration and curing time will be discussed to inform the selection of preparation parameters for specific tissues. Acoustic characterization proves to be a promising technique for evaluating the structure and function of the scaffolds and could serve as an indicator of tissue scaffold health while providing real-time monitoring in vivo.

Resonant ultrasound spectroscopy of cylindrically shaped sample of made of Ni-containing metallic glass alloy

Among different methods for determining elastic constants of a material, a special place belongs to the resonant ultrasound spectroscopy (RUS), as to a fast and non-destructive technique. We use a home-made RUS spectrometer to investigate the elastic properties of Ni71.5Cr5.6Nb3.4P16.5B3, a bulk metallic glass alloy (Ni-BMG). The sample was made by a counter-gravity suction casting technique and has shape of a cylinder. Modeling the measured spectrum of acoustic resonances for the sample in its cylindrical geometry was done with finite element analysis (FEA). FEA gives a longitudinal modulus (C11) of 300 GPa, and a Young's modulus (C44) of 50 GPa +/−5%. The determined values we verify by ultrasound pulse-echo technique, and compare them with the literature data for other Ni-bearing bulk metallic glass alloys. [This work was partially supported by NSF DMR award number 1709282. National High Magnetic Field Laboratory is supported by NSF/DMR-1644779 and the State of Florida.]

50 years real-time electronic sector scanning

In the early sixties many pioneers investigated the possibilities of ultrasound pulse-echo techniques for diagnostic purposes. The main areas were neurology, gynaecology & obstetrics, radiology and ophtalmology. The Institute of Medical Physics where I was employed had close connections with some neurologists pioneering in ultrasound for brain diagnostics. The experts often were relatively successful as far as it concerned A-scan. In contrast to this, attempts to obtain useful results with B-scan were very disappointing. I was convinced that the relative success of A-scan, in spite of its one-dimensional character, was due to the fact that A-scan is a true real-time system. That makes searching for the best picture possible by moving the probe slightly while observing the result simultaneously. The trials with all kinds of mechanical B-scan systems, in order to obtain two-dimensional pictures, suffered from the fact that one sees the result only after the scan is completed. The results were extremely disappointing for brain imaging, mainly due to irregularly shaped skull bone and its high absorption. I was absolutely convinced that two-dimensional scanning at a high repetition rate and with an essentially stationary probe would provide superior results. Observing moving objects, like the heart, would probably become possible. Both for brain and heart a probe with a small “footprint” is essential, as was the case already with A-scan equipment. In 1964 we decided to explore if such a new system is feasible. We would then have a fast B-scan system comparable with A-scan but with the vital difference that it is two-dimensional and real-time. We started to develop such a system of which the first prototype, the Electroscan, became operational in the beginning of 1969. It was able to produce real time ultrasound images in the form of a sector of 90 degrees, divided in 32 different directions, and with a scanning rate of 30 frames per second. This system was published at the 1st World Congress of the WFUMB in Vienna, 1969. This obviously explains the title of this lecture. We can say now that the success of electronic sector scanning has been enormous. It is applied in numerous medical areas. In echo-cardiography, for instance, the use of “phased array” has become almost exclusive. The Electroscan was developed in a period in which the computer and chip technology were relatively at a poor level. The fact that nowadays even 3-dimensional real-time scanners exist shows clearly how much ‘good ideas’ are dependant on technical developments.

Acoustic and mechanical characterization of 3D-printed scaffolds for tissue engineering applications

The acoustic and mechanical properties of 3D-printed porous poly-(ethylene glycol)-diacrylate (PEGDA) hydrogel scaffolds were investigated using an ultrasound pulse echo technique on different scaffold microstructures (solid, hexagonal and square pores). Acoustic parameters such as speed of sound, acoustic impedance and attenuation coefficient as well as physical parameters such as the pore structure, effective density and elastic moduli were determined. The results show that microstructure (porosity and pore geometry) plays a crucial role in defining properties of 3D-printed scaffolds, achieving the highest attenuation for the scaffold with hexagonal pores and showing a decrease in sound speed and elastic moduli with increasing porosity. The properties were also found to be similar to those of soft tissues, making PEGDA scaffolds a suitable candidate for tissue engineering applications. To evaluate their cellular performance, adhesion and proliferation of human mesenchymal stem cells (hMSCs) in these scaffolds were investigated. The porous scaffolds performed better than the solid one, recording the highest cell attachment and growth for the scaffold with the square pores.

Ultrasound Pulse-Echo Coupled with a Tracking Technique for Simultaneous Measurement of Multiple Bubbles.

Bubbly flows are commonly used in various applications and their measurement is an important research topic. The ultrasound pulse-echo technique allows for the detection of each bubble and the measurement of the position of its surface. However, so far it has been used only to measure single bubbles. This paper investigates whether the pulse-echo technique can be applied for measuring multiple bubbles concurrently. The ultrasonic transducer wavelength and diameter were selected based on expected bubble diameters so that each bubble produced a strong reflection. The pulse-echo was implemented to obtain good accuracy without sacrificing the signal processing speed. A tracking technique was developed for the purpose of connecting detected reflections to trajectories. The technique was tested experimentally by measuring the horizontal position of rising air bubbles in a water tank. The results show that the pulse-echo technique can detect multiple bubbles concurrently. The pulse-echo technique detected almost the same number of bubbles as a high-speed video. For average void fractions up to around (and instantaneous void fraction reaching ), the rate of bubbles missed by the pulse-echo and the rate of noise trajectories both stayed less than 5%. The error rate increased with the void fraction, limiting the technique’s application range.

Fully Automated and Robust Tracking of Transient Waves in Structured Anatomies Using Dynamic Programming

Tissue stiffness is often linked to underlying pathology and can be quantified by measuring the mechanical transient transverse wave speed (TWS) within the medium. Time-of-flight methods based on correlation of the transient signals or tracking of peaks have been used to quantify the TWS from displacement maps obtained with ultrasound pulse-echo techniques. However, it is challenging to apply these methods to in vivo data because of tissue inhomogeneity, noise and artifacts that produce outliers. In this study, we introduce a robust and fully automated method based on dynamic programming to estimate TWS in tissues with known geometries. The method is validated using ultrasound bladder vibrometry data from an in vivo study. We compared the results of our method with those of time-of-flight techniques. Our method performs better than time-of-flight techniques. In conclusion, we present a robust and accurate TWS detection method that overcomes the difficulties of time-of-flight methods.

Analysis of cooling effect by blood vessel on temperature rise due to ultrasound radiation in tissue phantom

Ultrasound diagnostic equipment using ultrasound pulse–echo techniques is considered minimally invasive and highly versatile. However, one of the causes of damage due to ultrasound radiation is temperature rise caused by the absorption of sound energy. Therefore, it is very important to estimate the temperature rise caused by the radiation of ultrasound. Sound intensity in a medium is analyzed by the finite-difference time-domain (FDTD) method, and the temperature distribution caused by sound is estimated by the heat conduction equation (HCE) method in this study. Because blood vessels keep the temperature constant in tissues, the cooling effect of blood flow has to be taken into account for the precise estimation of temperature rise in human tissues. In general, it is well known that capillary vessels are mainly responsible for the cooling effect in tissues and their effect can be estimated as a function of bloodstream ratio. In this paper, a preliminary study on the cooling effect by a large vessel is described for the precise estimation of temperature rise. Blood flow in blood vessels is analyzed using the Navier–Stokes equation. To confirm the precision of the numerical analysis, the results of the numerical analysis are compared with the experimental results using a soft tissue phantom.

Ultrasound bladder vibrometry method for measuring viscoelasticity of the bladder wall

Increase in bladder stiffness could be associated with various pathophysiologic conditions. Measuring bladder viscoelasticity could be an important step towards understanding various disease processes and improving patient care. Here, we introduce ultrasound bladder vibrometry (UBV), a novel method for rapid and noninvasive measurement of bladder wall viscoelasticity. UBV uses acoustic radiation force to excite mechanical waves in the bladder wall and track the motion using ultrasound pulse-echo techniques. Fourier domain analysis of the tissue motion versus time is used to calculate the phase velocity dispersion (change of phase velocity as a function of frequency). The measured phase velocity dispersion is fit with the antisymmetric Lamb wave model to estimate tissue elasticity and viscosity. We used finite element analysis of viscoelastic plate deformation to investigate the effect of curvature on Lamb wave dispersion and showed that the effects of curvature are negligible. The feasibility of the UBV technique was demonstrated in ex vivo and in vivo settings. Elasticity and viscosity of excised pig at various filling volumes (V) and pressures (p) were found to be µ1 = 9.6 kPa and µ2 = 0.2 Pa s (V = 187 ml and p = 8.6 mmHg), µ1 = 48.7 kPa and µ2 = 3.5 Pa s (V = 267 ml and p = 17.6 mmHg), and µ1 = 106.9 kPa and µ2 = 1.5 Pa s (V = 327 ml and p = 27.6 mmHg) respectively. Transabdominal measurements in an anesthetized pig found values of bladder elasticity µ1 = 26.1 kPa and viscosity µ2 = 0.9 Pa s and demonstrate the ability of UBV to perform in vivo measurements. The results presented in this paper introduce a novel technique for measuring mechanical properties of the bladder and lay the foundation for further investigation of the effects of pathology on bladder viscoelasticity.

High-resolution ultrasound displacement measurement using coded excitations

Resolution of displacement measurements based on ultrasound pulse-echo techniques is limited by the center frequency of the transmitted wave, echo sampling rate, quantization errors, and electronic noises in the measurement system. We developed a new method utilizing the clutter signal in coded excitations to determine the displacement of an object or a desired region of an object with much improved resolution. The method includes transmitting a pair of Golay complementary sequences, receiving echoes from the object or a region of the object, compressing the pulse, eliminating the main lobe, and determining the object displacement between the two transmissions from the residual clutter signal around the main lobe of the compressed pulse. Results of computer simulations showed that the new method improved the resolution by several orders of magnitude and was more robust to noise than traditional pulse-echo methods. The new method was also evaluated using an experimental ultrasound system (10 MHz center frequency, 100 MHz sampling rate, and 8-bit sampling precision). A high precision in the displacement measurement was achieved with a measurement error of ¿5.76 nm ±36.27 nm (mean ± standard deviation). The method has the potential to be applied in biomedical and industrial measurements of distance, displacement, and thickness.

Role of Injection in Hybrid Rockets Regression Rate Behaviour

A series of firing tests was carried out to investigate the influence of the oxidizer injection on the solid fuel regression rate behavior in a hybrid rocket engine. For this purpose, a conical subsonic nozzle as the injector of the gaseous oxidizer was selected to generate nonuniform conditions at the entrance of the fuel port. Gaseous oxygen and polyethylene fuel cylindrical grains were used. When the oxygen was fed by this kind of injector, the fuel regression in the region of the oxygen impingement on the grain’s surface was increased several times, which led to irregular fuel consumption with the characteristic afterburn port shape typical of solid fuel ramjets having a rearward-facing step at the air inlet. The local instantaneous regression rates, measured by means of the ultrasound pulse-echo technique, showed regression rate-time profiles strongly dependent on the geometric configuration and helped to explain the complex regression phenomenon deriving from the impingement zone displacement during the time. Empirical correlations for the prediction of the average regression rate were developed taking into account the influence of mass flux, pressure, and port diameter. Finally, a nondimensional semi-empirical correlation involving the effect of the blowing number yielded improved accuracy.

Ultrasonic studies of unblemished and artificially demineralized enamel in extracted human teeth: a new method for detecting early caries

Ultrasonic imaging of unblemished and artificially demineralized enamel in extracted human teeth was investigated using ultrasound of 18 MHz centre frequency. Double-blind experiments were performed on extracted permanent teeth which had two small ‘window’ areas on their labial enamel surfaces demineralized in 6 per cent hydroxyethylcellulose gel for 1, 3 or 7 days, to produce lesions analogous to early dental caries. The degree of demineralization was determined from densitometry of contact microradiographs of sections of the cervical half of each specimen. The incisal halves were separately scanned by the ultrasound pulse-echo technique to obtain blind and independent acoustic information on the degree of demineralization. Artificial enamel lesions with less than 57 per cent mineral content (where intact enamel = 100 per cent on microradiographs) in the body of the lesion can be differentiated acoustically from intact enamel on the basis of relative amplitude changes of the enamel surface echo and the amelodentinal junction (ADJ) echo. An apparent correlation exists between the mineral content of the body of the lesion and the relative echo amplitude changes, and is explained by changes in specific acoustic impedance. It is hypothesized that the profile of the carious lesion may be deduced from time-of-flight graphs of the enamel surface echo and the ADJ echo.