Measurement Of Acoustic Properties Research Articles

Review of the Low-Temperature Acoustic Properties of Water, Aqueous Solutions, Lipids, and Soft Biological Tissues.

Existing data on the acoustic properties of low-temperature biological materials is limited and widely dispersed across fields. This makes it difficult to employ this information in the development of ultrasound applications in the medical field, such as cryosurgery and rewarming of cryopreserved tissues. In this review, the low-temperature acoustic properties of biological materials, and the measurement methods used to acquire them were collected from a range of scientific fields. The measurements were reviewed from the acoustic setup to thermal methodologies for samples preparation, temperature monitoring, and system insulation. The collected data contain the longitudinal and shear velocity, and attenuation coefficient of biological soft tissues and biologically relevant substances-water, aqueous solutions, and lipids-in the temperature range down to -50 °C and in the frequency range from 108 kHz to 25 MHz. The multiple reflection method (MRM) was found to be the preferred method for low-temperature samples, with a buffer rod inserted between the transducer and sample to avoid direct contact. Longitudinal velocity changes are observed through the phase transition zone, which is sharp in pure water, and occurs more slowly and at lower temperatures with added solutes. Lipids show longer transition zones with smaller sound velocity changes; with the longitudinal velocity changes observed during phase transition in tissues lying between these two extremes. More general conclusions on the shear velocity and attenuation coefficient at low-temperatures are restricted by the limited data. This review enhance knowledge guiding for further development of ultrasound applications in low-temperature biomedical fields, and may help to increase the precision and standardization of low-temperature acoustic property measurements.

Least-squares approach for improving the accuracy of bulk acoustic property measurements using an impedance tube

The bulk acoustic property (characteristic impedance, propagation wave number, or propagation constant) of porous acoustic material with an impedance tube is generally calculated by the two-cavity method, which is calculated from the specific acoustic impedance obtained by the two-microphone transfer function method (ASTM E1050, ISO 10534-2) or from the transfer matrix measured by the four-microphone transfer matrix method (ASTM E2611). These methods can obtain the bulk acoustic property from the results of up to two measurements with different termination conditions. However, the bulk acoustic property may not be obtained correctly due to calculation singularities caused by the test specimen and/or measurement conditions, and calculation errors caused by setting errors regarding the dimensions or environmental conditions of the tube nd/or test specimen. As a result, to reduce the errors in the bulk acoustic property, workarounds such as measuring the specific acoustic impedance or transfer matrix under multiple termination conditions (n conditions) and averaging the bulk acoustic properties obtained for all combinations of two termination conditions have sometimes been used. Therefore, to improve the error in the bulk acoustic properties, a new calculation method based on the least squares method using all the data measured under multiple termination conditions is proposed.

Sound speed and attenuation of human pancreas and pancreatic tumors and their influence on focused ultrasound thermal and mechanical therapies.

There is increasing interest in using ultrasound for thermal ablation, histotripsy, and thermal or cavitational enhancement of drug delivery for the treatment of pancreatic cancer. Ultrasonic and thermal modelling conducted as part of the treatment planning process requires acoustic property values for all constituent tissues, but the literature contains no data for the human pancreas. This study presents the first acoustic property measurements of human pancreatic samples and provides examples of how these properties impact a broad range of ultrasound therapies. Data were collected on human pancreatic tissue samples at physiological temperature from 23 consented patients in cooperation with a hospital pathology laboratory. Propagation of ultrasound over the 2.1-4.5MHz frequency range through samples of various thicknesses and pathologies was measured using a set of custom-built ultrasonic calipers, with the data processed to estimate sound speed and attenuation. The results were used in acoustic and thermal simulations to illustrate the impacts on extracorporeal ultrasound therapies for mild hyperthermia, thermal ablation, and histotripsy implemented with a CE-marked clinical system operating at 0.96MHz. The mean sound speed and attenuation coefficient values for human samples were well below the range of values in the literature for non-human pancreata, while the human attenuation power law exponents were substantially higher. The simulated impacts on ultrasound mediated therapies for the pancreas indicated that when using the human data instead of the literature average, there was a 30% reduction in median temperature elevation in the treatment volume for mild hyperthermia and 43% smaller volume within a 60°C contour for thermal ablation, all driven by attenuation. By comparison, impacts on boiling and intrinsic threshold histotripsy were minor, with peak pressures changing by less than 15% (positive) and 1% (negative) as a consequence of the counteracting effects of attenuation and sound speed. This study provides the most complete set of speed of sound and attenuation data available for the human pancreas, and it reiterates the importance of acoustic material properties in the planning and conduct of ultrasound-mediated procedures, particularly thermal therapies.

Study of intermolecular interactions present in ternary mixtures containing sugar alcohol and choline chloride at different temperatures

Artificial sweeteners also called non-calorific sweeteners are gaining popularity due to their sweet taste and metabolically inert nature. A lot of chemically designed artificial sweeteners are available in food industry. A type of artificial sweeteners is sugar alcohol, which have been used various food items and hence occupying a large place in food sector as well as in pharmaceutical industries. Erythritol, a sugar alcohol has been used in the present study as one of the component of ternary mixture. Other important constituent of the study is choline chloride. Choline is a primary metabolite that provides methyl groups required for the process of metabolism. Choline is key component that is utilized in the synthesis of two vital cell membrane phospholipids: phosphatidylcholine and sphingomyelin. Being a neurotransmitter, it also play an important role in balancing mood, memory and intelligence. To study the solvation behavior and collecting information regarding chemoreception, measurement of volumetric and acoustic properties of erythritol with choline chloride have been reported in this paper. By using the raw data of density and ultrasonic velocity measured by DSA 5000 of sound, different apparent molar properties of an non calorific sweetener (erythritol) have been computed for binary mixtures of different concentrations with water and ternary mixtures with choline chloride at different temperatures. Furthermore, other useful parameters for solvation have also been calculated like limiting apparent molar expansion, Eϕ0, specific volume, vϕ, hydration numbers etc. The obtained results have been discussed for interactional behavior related to structure changes in the studied systems.

Unraveling the link between sediment acoustics and organic carbon

The top meter of marine sediments is estimated to store a total of 2322 Pg of carbon [Atwood et al., 2020. Front. Mar. Sci., vol. 7 p.165], which is twice that of terrestrial soils. Physical disturbance and remineralization of these carbon stocks could further accelerate climate change. Rapid and accurate quantification of sediment carbon stocks can (1) better inform carbon budgets and management of human activities in the ocean to minimize carbon remineralization and (2) monitor changes in sediment carbon stocks due to anthropogenic and natural disturbances. Sediment acoustics, which have been linked with sediment total organic carbon/content in mud banks, seagrass beds, and estuarine environments, can be measured in situ and offer a scalable solution toward rapid estimation of carbon stocks. However, before this modality can be applied broadly, a fundamental understanding between sediment acoustic properties and sediment organic/inorganic constituents must be realized. Here, direct ex situ measurements of sediment acoustic properties, sediment organic carbon, and grain size distribution will be compiled and compared across a variety of sediment types and locations from our own measurements and from published datasets. The development of a non-site-specific constitutive-based relationship will be discussed. [Work supported in part by ONR.]

High-frequency quantitative ultrasound for the assessment of the acoustic properties of engineered tissues in vitro.

Acoustic properties of biomaterials and engineered tissues reflect their structure and cellularity. High-frequency ultrasound (US) can non-invasively characterize and monitor these properties with sub-millimetre resolution. We present an approach to estimate the speed of sound, acoustic impedance, and acoustic attenuation of cell-laden hydrogels that accounts for frequency-dependent effects of attenuation in coupling media, hydrogel thickness, and interfacial transmission/reflection coefficients of US waves, all of which can bias attenuation estimates. Cell-seeded fibrin hydrogel disks were raster-scanned using a 40 MHz US transducer. Thickness, speed of sound, acoustic impedance, and acoustic attenuation coefficients were determined from the difference in the time-of-flight and ratios of the magnitudes of US signals, interfacial transmission/reflection coefficients, and acoustic properties of the coupling media. With this approach, hydrogel thickness was accurately measured by US, with agreement to confocal microscopy (r2 = 0.97). Accurate thickness measurement enabled acoustic property measurements that were independent of hydrogel thickness, despite up to 60% reduction in thickness due to cell-mediated contraction. Notably, acoustic attenuation coefficients increased with increasing cell concentration (p<0.001), reflecting hydrogel cellularity independent of contracted hydrogel thickness. This approach enables accurate measurement of the intrinsic acoustic properties of biomaterials and engineered tissues to provide new insights into their structure and cellularity. STATEMENT OF SIGNIFICANCE: High-frequency ultrasound can measure the acoustic properties of engineered tissues non-invasively and non-destructively with µm-scale resolution. Acoustic properties, including acoustic attenuation, are related to intrinsic material properties, such as scatterer density. We developed an analytical approach to estimate the acoustic properties of cell-laden hydrogels that accounts for the frequency-dependent effects of attenuation in coupling media, the reflection/transmission of ultrasound waves at the coupling interfaces, and the dependency of measurements on hydrogel thickness. Despite up to 60% reduction in hydrogel thickness due to cell-mediated contraction, our approach enabled measurements of acoustic properties that were substantially independent of thickness. Acoustic attenuation increased significantly with increasing cell concentration (p<0.001), demonstrating the ability of acoustic attenuation to reflect intrinsic physical properties of engineered tissues.

Multiphysics Experimental Approaches for Insight into the Hydrogen Bonded Structures of Ethylene Glycol and Glycerol Mixtures toward Green Solvent Technology

Alcohols and their mixtures are credited most important polar solvents for advances in pharmaceutical, chemical,biological, thermal, and material technologies. A rigorous study for the characterization of hydrogen bonded heterogeneousintermolecular structures that formed in a mixed solvent based on alcohols containing two and three hydroxyl groupsmolecules is crucial to specific technological and industrial applications. Hence, in this work, the multiphysics experimentalapproaches including the measurements of dielectric, electrical, viscous, acoustic, thermal, and optical properties are appliedand analyzed to confirm the behaviour of hydrogen bonded molecular structures of ethylene glycol (EG; dihydric alcohol)with glycerol (Gl; trihydric alcohol) over the entire concentration range of EG+Gl mixtures at 298.15 K. The static dielectricpermittivity, direct current electrical conductivity, low frequency relaxation time, and refractive index values of the EG+Glmixtures are reported. Additionally, dynamic viscosity, density, ultrasound velocity, adiabatic compressibility,intermolecular free length, acoustic impedance, free volume, Rao’s constant, Wada constant, and viscoacoustic relaxationtime of the EG+Gl mixtures are determined, and also explored their significance to these alcohols molecular interactions.Ultraviolet-visible range absorbance behaviour of the alcohol mixtures is characterized in detail and confirmed theelectronic transitions at higher energy ultraviolet radiations. The detailed analysis of all the experimental results along withthe consideration of excess properties evidenced the formation of heterogeneous intermolecular hydrogen bonded structuresin these Newtonian-type alcohols mixtures. A small to adequate variation in the thermodynamical and other investigatedproperties with the concentration variation showed that the EG+Gl mixture can be optimized as a green solvent according tothe prerequisite properties for huge advances in soft condensed matter technologies.

Acoustic-Wave Radiations of Mono- and Dual-Sources in Poorly Bonded Cased Boreholes: Modeling and Field Applications

Measurement of formation acoustic properties from cased-hole acoustic logging is often problematic when the casing is poorly bonded with formation. A dual-source technology has been used to measure formation acoustic properties through casing, and the development of this dual-source technology requires an understanding of the effects of acoustic-wave radiation. Here, I have derived the theoretical formulations for the acoustic-wave radiation in well and poorly bonded cased boreholes, and simulated the acoustic-wave radiation excited by dual-source and monopole sources under various casing-cement bonding conditions. The analytical modeling results showed that the formation signal excited by acoustic dual-source can be significantly enhanced, indicating the advantages of this dual-source design in cased borehole. The modeling results were applied to interpret acoustic data acquired in cased boreholes, where theoretical predictions and measurements were in good agreement.

Direct measurements of acoustic and physical properties in mud and comparison to sediment acoustics models

Sediment acoustics models relate seabed physical properties to acoustic wave speed and attenuation, and direct measurements of sediment acoustic and physical properties provide a means to test such models. We examine direct measurements from two field experiment sites with muddy sediments that contain different ratios of clay, silt, sand, and organic components, comparing the acoustic data with sediment acoustic model predictions using parameters obtained from cores as model inputs. In the New England Mud Patch, sediment sound speed profiles up to several meters below the seabed surface were measured using in situ acoustic probes mounted to a gravity corer. At a second site near Mobile Bay, in situ probe measurements of sound speed, attenuation, and shear speed were obtained in the upper 20 cm of sediment, and diver cores were collected and scanned with an acoustic core logger. Sediments from both sites were analyzed for porosity and grain size distribution. The applicability of various models to the mud found at each site will be discussed, as well as effects of infauna and organic matter, which were also measured, but are not explicitly included in the models. [Work sponsored by ONR.]

Toward predicting Arctic Ocean acoustic travel times using an Earth system model

The hydroacoustic environment of a rapidly warming Arctic Ocean will be impacted by changing thermohaline structure, increased marine traffic, changes in sea ice coverage, and likely increases in microseism/storm noise. This will lead to obsolescence for today’s Arctic Ocean acoustic models just as the need for understanding and monitoring the Arctic acoustic environment becomes more critical. To make sophisticated predictions for coming conditions, we need fully-coupled Earth system models. Los Alamos National Laboratory is contributing to developing the Department of Energy’s Energy Exascale Earth System Model (E3SM), which can potentially predict the ocean and sea ice conditions necessary to drive an acoustics model in a rapidly-evolving Arctic Ocean. We present a preliminary analysis of a comparison of acoustic travel times in the Canada Basin calculated from E3SM simulations with measured travel times from the 2016–2017 Canada Basin Acoustic Propagation Experiment (CANAPE) and travel times computed from ice-tethered-profiler measurements of acoustic properties in the water column. The goals of this effort are to provide boundary ocean conditions to an acoustic model, to quantify the ocean acoustic implications of climate change, as well as to create a climate-aware atlas of global acoustic noise that could be applied, for example, in signal detection.

Analysis and Research on the Use of Bulk Recycled Materials for Sound Insulation Applications

The application of recycled materials from the automotive industry in the field of the construction industry is a suitable alternative application for these materials and the use of their acoustic and thermal insulation properties. The output of recycling is granular, or chopped materials that can be used as a substitute for conventional materials. One of the important features of building materials is their acoustic properties. The measurement and evaluation of acoustic properties is carried out using an impedance tube as equipment. Measuring compact materials is quite simple and requires the preparation of a sample. Measuring the acoustic properties of granular bulk materials is more complicated and requires the development and production of a special test cartridge. Recycled bulk materials from the automotive industry such as rubber granules and chopped textiles can be applied as fillings for dividing structures. The aim of this paper was to assess the acoustic properties of different fractions of recycled rubber granules and textile chopped material and to compare acoustic properties with compact rubber and textile panels. To evaluate and compare sound absorption coefficient (α) and sound transmission loss (R) parameters, we used basic statistical methods and hypothesis testing methods. The production of compact panels is quite expensive since it is necessary to use special synthetic binders in production, and the content of these substances can also have negative effects on the environment. Based on the results of measuring the acoustic properties of bulk recycled materials and comparing them with compact materials, we can conclude that bulk recycled rubber and textile materials have very good values for their acoustic properties, which enables them to be used in several areas of industry.

3Pb1-3 Measurement of Acoustic Properties for Liquid Metal Couplers with Low Melting Point and High Acoustic Impedance

3Pb1-3 Measurement of Acoustic Properties for Liquid Metal Couplers with Low Melting Point and High Acoustic Impedance

Nonlinear control of boundary impedance in an acoustic waveguide.

Wavetubes are employed for measurements of acoustic properties in various fluids. The ability to manipulate and control the frequency-dependent boundary impedance of the tube improves the estimation accuracy. Passive solutions, which use composite materials to change the boundary impedance, enable one to realize a finite combination of boundary impedances. In this paper, the tube boundary impedance is tuned at will by using two loudspeakers. The suggested method operates in the presence of dispersion by estimating, in real-time, a parametric reduced-order model using a multichannel least mean square algorithm. The identified model is fed to a nonlinear, adaptive control algorithm to realize modal traveling wave ratio (TWR) control. It has been noted that the TWR is smooth and parabolic across closed regions in the parameter space, thus assuring the convergence of the nonlinear control. Several methods to estimate the TWR gradient are considered and compared based on an analytical model of a rigid impedance tube. An experimental case study utilizing an air-filled impedance tube with two loudspeakers is presented. The results demonstrate the ability to control the dynamics of the principal acoustic mode at will, thus enabling one to set the desired tube's boundary impedance.

Experimental investigation of parametric array for low frequency measurement system

To evaluate the performance of an equipment or object in underwater acoustics, the acoustic properties of acoustic materials should be accurately predicted and measured. The measurement of acoustic properties via panel testing in water tank require a narrow beam due to unwanted signals such as reflection from walls and diffraction signal. However, in the case of low frequency sound source, it generally has broad beam, and in order to have narrow beam, it is difficult to operation and physical limitation. These limitations and problems can be overcome by using a small size of parametric array capable of generating high-directional low-frequency signals. In order to use the parametric array as a sound source for an acoustic measurement system, it is necessary to understand the characteristics of the parametric array in near field. So this study was performed an experimental investigation on parametric arrays and study to construct an optimal system. Numerous factors such as the effect of pseudo sounds and the optimal distance between the source and receiver were considered to construct the system, and the results of experimental investigations, such as an efficient method to remove the effects of pseudo sounds and effective length, were confirmed.

Acoustic Properties of Steel Bridge Base Metals

ABSTRACT Ultrasonic testing (UT) is typically conducted to locate and classify (or rate) defects in welds during bridge fabrication. Variations in acoustic properties such as attenuation and velocity can have an impact on the UT results. Defects in welds may be missed, incorrectly rated, or incorrectly located, and false calls may occur that require unnecessary repairs. The objective of the research was to assess the impact of variations in acoustic properties on the ultrasonic testing of bridge steel. This paper describes the results of acoustic property measurements of 14 different material heats representing various grades of steel plate used in bridges. The attenuation of various bridge base materials was evaluated using 2.25 MHz and 5 MHz transducers. Shear wave velocities and acoustic anisotropy ratios were also determined for some of these steels using normal incidence shear wave and electromagnetic acoustic (EMAT) transducers. The experimental results as well as CIVA-UT simulation software were used to develop recommended changes to the AWS D1.5 Bridge Welding Code in order to limit the amplitude and location measurement errors for weld flaws.

Method for controlling boundary condition effects on the measurement of acoustic properties of small samples in tubes.

As standard ASTM E2611 reveals, the normal incidence sound transmission loss measured on a small sample in an acoustic tube is not only a property of the material but also strongly dependent on boundary conditions (generally unknown) and on the way the material is mounted. This article proposes an experimental method to control the effects of the lateral boundary conditions in an acoustic tube. The main objective is to deduce the properties of a "client element" (material sample) from the measured global acoustic properties of a patchwork composed by the "client material" and a known "host support." Three patchwork configurations have to be distinguished: patchworks with and without an impervious and rigid interface between the elements and patchworks composed by elements that cannot be identified as equivalent fluids. For each of these configurations, the use of a specific method based on the Mixing Rule Method (MRM) or on the Parallel Transfer Matrix Methods (P-TMM or dP-TMM) used in reverse way is proposed. Numerical and experimental validations are proposed in acoustic tubes on a convenient configuration: a material sample surrounded by an air ring. This configuration allows reducing the material elastic-frame behavior to leave a limp-frame behavior. The proposed methods allow removing the effect of the lateral air ring host surrounding the material. For homogeneous materials, the two methods based on MRM and dP-TMM give similar good results. For non-homogeneous materials or for materials that cannot be modeled as equivalent fluids, only the method based on dP-TMM gives good results.

Explainable machine learning determines effects on the sound absorption coefficient measured in the impedance tube.

Measurements of acoustic properties of sound absorbing materials in impedance tubes show poor reproducibility, which was demonstrated in round robin tests. The impedance tube measurements are standardized but lack precise definitions of the actual measurement setup, specimen preparation, and other factors that introduce uncertainty in practice. In this paper, machine learning models identify those factors that mostly affect the sound absorption coefficient from a large data set of more than 3000 absorption spectra measured in one impedance tube. The specimens are manufactured from one polyurethane foam, and different cutting technologies, different operators, different specimen diameters, different specimen thicknesses, and two different approaches to mount the specimens in the impedance tube are considered. Explainable machine learning techniques allow the identification and quantification of the most influential factors and, furthermore, the frequency ranges that are the most affected by the choice of these setup factors. The results indicate that besides the specimen thickness, also the operator affects the absorption coefficient by a directional and non-random relationship. Hence, it needs to be controlled carefully. The method proves to be a promising pathway for knowledge discovery from acoustic measurement data using explainability approaches for machine learning models.

ANALYSING ACOUSTIC PROPERTIES OF A SUBWAY TRACK

This paper describes laboratory measurement of acoustic properties of subway track samples, with the main focus on the change of the basic material of selected components of a rail fastening system. They were identical in shape, the only difference was in the material used. A suitable methodology based on measuring the acoustic response to mechanical shock was developed for laboratory measurements. The measured data was assessed with an appropriate mathematical apparatus based on signal analysis methods in the time and frequency domain. Based on the tests performed, the acoustic properties of the structures examined were deter

Evaluation of material degradation using phased array ultrasonic technique with full matrix capture

This paper presents a new approach based on phased array ultrasonic technique (PAUT) with full matrix capture (FMC) to effectively measure acoustic properties such as ultrasonic wave velocity and attenuation coefficient and to evaluate material degradation. This paper also proposes the use of PAUT with FMC, to simultaneously generate and detect ultrasonic waves such as longitudinal, shear, and Rayleigh waves in the material. A theoretical model is developed to derive the analytical solution of ultrasonic waves induced in the material by an ultrasonic phased array probe. Based on the theoretical prediction, experiments are carried out on AISI 316L stainless steel specimen of 3 mm thickness, and a 2D finite element model is built to verify the generation and detection of these waves. Furthermore, measurements of acoustic properties are carried out on the specimen using the proposed approach as well as the conventional ultrasonic testing (CUT) technique and their sensitivities are compared. The measurements of time-of-flight and back-wall echo amplitude are more accurate with the proposed approach than the CUT technique, which makes the former technique better than the latter for the evaluation of material degradation. Finally, experiments are performed on AISI 316L specimen degraded with different levels of tensile stress to verify the capability of PAUT with FMC. The results show that the velocities and attenuation coefficient increase with an increase in tensile stress until material fracture. This phenomenon is interpreted as resulting from microstructural changes such as dislocations during material degradation. From the experimental results, it is proposed that PAUT with FMC can potentially be used to evaluate early-stage materials degradation.

Pulse-echo acoustic properties evaluation method using high-frequency transducer

The quantitative measurement of acoustic properties is indispensable for many applications. The realization of devices for the evaluation of acoustic properties with higher accuracy and lower error is of great importance. Moreover, the ability to obtain the high-frequency acoustic characteristics of materials is also highly desirable. In this research, the pulse echo method is applied to measure a material’s acoustic parameters, using a miniature transducer with a center frequency of 42.9 MHz. For this method, only one transducer is needed, and the measurement system is simple. Acoustic parameter calculation methods for three types of materials are studied, and the corresponding experiments are conducted. The experimental results show that the sound velocity of water is 1508.8 m s−1, and its attenuation coefficient is 0.981 dB mm−1; the results for liquid paraffin give results of 1386.8 m s−1 and 2.35 dB mm−1, respectively. With reference to polymer materials, thermoplastic polyurethane (TPU) thin film has a sound velocity of 1987.2 m s−1 and an attenuation of 37.1 dB mm−1, and polyimide thin film has a sound velocity of 2142.3 m s−1 and an attenuation of 25 dB mm−1. In terms of ceramics, the sound velocity of PZT-5H 3203HD is 4804.2 m s−1, and its attenuation is 1.71 dB mm−1; 96% alumina ceramic has a sound velocity of 9924.9 m s−1 and its attenuation 1.18 dB mm−1. All results pertaining to sound velocity agree well with those reported in previous works. The measured attenuation coefficients at high frequency are also in good agreement with the experimental data. All experimental results validate the feasibility, effectiveness, convenience, and accuracy of this method.