Low Ultrasonic Attenuation Research Articles

Ice matrix composites for Cryo-ultrasonic testing

Cryo-ultrasonic testing utilizes polycrystalline ice coupling to enable the inspection of metallic components with complex shape. The relatively high velocity of compressional waves in ice (approximately 4000 m s−1) and its ability to support the propagation of shear waves, significantly strengthen the ultrasonic transmission through curved interfaces over conventional water coupling. This paper explores the possibility of further enhancing the ultrasonic properties of ice by dispersing solid particles in water before it is frozen. Complex physicochemical phenomena occur when aqueous dispersions freeze which can lead to a solid material with microstructural characteristics that may be unfavorable to the propagation of ultrasonic waves. Here, these effects are controlled to produce a composite material consisting of alumina nanoparticles in an ice matrix. The composite exhibits compressional and shear wave velocities of approximately 4800 m s−1 and 2700 m s−1 , respectively. Importantly, the mass density of the material is more than twice as large as the density of water. Finally, it is shown that a phenomenon similar to a glass transition occurs during freezing which results in low ultrasonic attenuation when the temperature approaches – 100 °C.

Numerical and experimental investigations on quasistatic pulse generation of ultrasonic guided waves in fiber reinforced composite pipes

The quasistatic pulse (QSP) generation of ultrasonic guided waves in composite pipes can exhibit many features that are useful for early-stage material characterization and structural health monitoring. The intrinsic relationship between the QSP generation and the weak elastic nonlinearity of solids is complex. It has yet promised for developing the nonlinear ultrasonic guided wave technique that combines its advantages of high sensitivity to microdamage and low ultrasonic attenuation in composite materials. This study presents a systematic investigation of the QSP generation in fiber reinforced composite pipes. Using a three-dimensional finite element simulation with a nonlinear material model, the temporal waveform, mode conversion effect, cumulative effect, generation efficiency, and duration effect of QSP generation are revealed. The nonlinear QSP signals in laminated composite pipes are confirmed as the fastest wave mode that only has axial displacement. The shape of QSP depends on the group velocity difference between the QSP and the primary wave. The magnitude of QSP is related to the excitation level, frequency, and tone-burst duration of the primary wave. Experiments are conducted using carbon fiber reinforced composite pipes and the signals are measured using a laser vibrometer scanning system for verifying the QSP generation. The experimental results are consistent with the numerical findings. A relative nonlinear acoustic parameter based on the QSP generation is proposed and used to evaluate the early-stage thermal fatigue damage in the pipes. The measured nonlinear acoustic parameter demonstrates high sensitivity to the damage, indicating considerable potential for industrial applications.

Characterization of the mechanical properties of high-moisture meat analogues using low-intensity ultrasound: Linking mechanical properties to textural and nutritional quality attributes

Plant-based meat analogues offer possible alternatives to meat consumption. However, many challenges remain to produce a palatable meat analogue as well as to understand the roles of different processing steps and ingredients on both the texture and nutritional properties of the final product. The goal of this paper is to help with addressing these challenges by using a low-intensity ultrasonic transmission technique, both online and 24 h after production, to investigate high-moisture meat analogues made from a blend of soy and wheat proteins. To understand the ultrasonic data in the context of traditional characterization methods, physical properties (meat analogue thickness, density, peak cutting force) and protein nutritional quality attributes of the meat analogues were also characterized separately. The ultrasonic velocity was found to decrease with the feed moisture content and to be strongly correlated (r = 0.97) with peak cutting force. This strong correlation extends over a wide range of moisture contents from 58% to 70%, with the velocity decreasing from about 1730 m/s to 1660 m/s over this range. The protein quality was high for all moistures, with the highest amino acid score and in vitro protein digestibility being observed for the highest moisture content treatment. The accuracy of the ultrasonic measurements was enhanced by the development of an innovative non-contact method, suitable for materials exhibiting low ultrasonic attenuation, to measure the meat analogue thickness ultrasonically and in a sanitary fashion – an advance that is potentially useful for online monitoring of production problems (e.g., extruder barrel-fill and cooling-die temperature issues). This study demonstrates, for the first time, the feasibility of using ultrasonic transmission techniques to measure both velocity and sample thickness simultaneously and provide information in real time during production that is well correlated with some textural and nutritional attributes of meat analogues.

Mechanical, Elastic and Thermal Properties of Hexagonal BC<sub>2</sub>N Superhard Material

The ultrasonic properties of the hexagonal BC2N superhard material were studied at temperature-dependent following the interaction potential model. Higher-order elastic constants are used for the determination of other ultrasonic parameters. The temperature variation of the ultrasonic velocities is evaluated along with different angles with z-axis (unique axis) of the crystal using the second-order elastic constants temperature variation of the thermal relaxation time, and Debye average velocities are also calculated along with the same orientation. The temperature dependency of the acoustic properties is discussed in correlation with elastic, thermal, and mechanical properties. It has been found that thermal conductivity and thermal energy density are the main contributors to the behavior of ultrasonic attenuation as a function of temperature. The responsible cause of attenuation is phonon-phonon interaction. Mechanical properties of BC2N superhard material at temperature 400K are better than at other temperatures because, at this temperature, it has low ultrasonic attenuation. Superhard material BC2N has many industrial and engineering applications.

Label-free imaging of lipid-rich biological tissues by mid-infrared photoacoustic microscopy.

.Significance: Mid-infrared (IR) imaging based on the vibrational transition of biomolecules provides good chemical-specific contrast in label-free imaging of biology tissues, making it a popular tool in both biomedical studies and clinical applications. However, the current technology typically requires thin and dried or extremely flat samples, whose complicated processing limits this technology’s broader translation.Aim: To address this issue, we report mid-IR photoacoustic microscopy (PAM), which can readily work with fresh and thick tissue samples, even when they have rough surfaces.Approach: We developed a transmission-mode mid-IR PAM system employing an optical parametric oscillation laser operating in the wavelength range from 2.5 to . Due to its high sensitivity to optical absorption and the low ultrasonic attenuation of tissue, our PAM achieved greater probing depth than Fourier transform IR spectroscopy, thus enabling imaging fresh and thick tissue samples with rough surfaces.Results: In our spectroscopy study, the symmetric stretching at (3508 nm) was found to be an excellent source of endogenous contrast for lipids. At this wavenumber, we demonstrated label-free imaging of the lipid composition in fresh, manually cut, and unprocessed tissue sections of up to 3-mm thickness.Conclusions: Our technology requires no time-consuming sample preparation procedure and has great potential in both fast clinical histological analysis and fundamental biological studies.

A traveling-wave ultrasonic motor utilizing a ring-shaped alumina/PZT vibrator

Considering that high Young’s moduli and low ultrasonic attenuation of fine ceramics may enhance driving force and reduce energy dissipation, in this study, we exploit the usage of fine ceramics as vibrating bodies of ultrasonic motors. Several alumina vibrating bodies were fabricated and bonded to annular lead-zirconate-titanate (PZT) disks to form ring-shaped vibrators, where traveling waves with the 3rd bending modes were excited to frictionally drive the rotor. First, we explored the fundamental vibration properties. As predicted, the alumina/PZT vibrators provided relatively high force factors, high electromechanical coupling factors, and low damping compared to the stainless-steel/PZT one with similar structure. Subsequently, through experimental assessment on load characteristics, we found that the rotation speed of the alumina/PZT motor at 20 V was larger than that of the stainless-steel/PZT motor at 250 V, and meanwhile, it exhibited superior maximal-torque-to-voltage and maximal-output-power-to-voltage ratios; these results imply that satisfactory performance is achievable with our motor. Besides, alumina’s chemical resistance and electrical resistance make our motor potentially applicable to the acid/alkaline atmosphere and the intensively alternating-current magnetic field.

Non-destructive characterization of superionic conductor: lithium nitride

Abstract Higher order elastic constants have been calculated in hexagonally structured superionic conductor Li3N at room temperature using the interaction potential model. The temperature variation of the ultrasonic velocities was evaluated along different angles with z axis (unique axis) of the crystal, using the second order elastic constants. The ultrasonic velocity decreased with the temperature along a particular orientation of the unique axis. Temperature variation of the thermal relaxation time and Debye average velocities was also calculated along the same orientation. The temperature dependency of ultrasonic properties was discussed in correlation with elastic, thermal and electrical properties. It has been found that the thermal conductivity is the main contributor to the behavior of ultrasonic attenuation as a function of temperature and the cause responsible for attenuation is phonon-phonon interaction. The mechanical properties of Li3N at low temperature are better than at high temperature because at low temperature it has low ultrasonic attenuation. Superionic conductor lithium nitride has many industrial applications, such as those used in portable electronic devices.

ELASTIC AND ACOUSTIC PROPERTIES OF HEXAGONALCr2NbCOMPOUND

The ultrasonic properties like ultrasonic sound velocity in the hexagonal structured Cr2Nb compound have been studied along unique axis at room temperature. The second- and third-order elastic constants (SOECs and TOECs) have been calculated for this compound using Lennard–Jones potential. The velocities VLand VS1have minima and maxima respectively with 45° with unique axis of the crystal, while VS2increases with the angle from unique axis. Debye average sound velocities of Cr2Nb have been found to be increasing with the angle and has maximum at 55° with unique axis at room temperature. Hence, when a sound wave travels at 55° with unique axis of this material, then the average sound velocity is found to be maximum. The inconsistent behavior of angle dependent velocities is associated to the action of SOECs. The ultrasonic properties are discussed in correlation with elastic, thermal and electrical properties. It has been found that the thermal conductivity is the main contributor to the behavior of ultrasonic attenuation and the cause of attenuation is phonon–phonon interaction. The mechanical properties of Cr2Nb are better than other chromium-based alloys ( Cr2Ta , Cr2Zr and Cr2Hf ) at room temperature, because it has high ultrasonic velocity and low ultrasonic attenuation.

Effect of Elastic Constants on the Ultrasonic Properties of Group VIB Transition Metal Diborides

The ultrasonic properties like ultrasonic attenuation, sound velocity in the group VIB transition metal diborides like CrB2 and MoB2 have been studied along unique axis at room temperature. The second- and third order elastic constants (SOEC & TOEC) have been calculated for these diborides using Lennard- Jones potential. The velocities VL and VS2 increases with the angle from the unique axis and VS1 have maximum at 45 0 with unique axis of the crystal. The inconsistent behaviour of angle dependent velocities is associated to the action of second order elastic constants. Debye average sound velocities of these compounds are increasing with the angle and has maximum at 55 0 with unique axis at room temperature. Hence when a sound wave travels at 55 0 with unique axis of these materials, then the average sound velocity is found to be maximum. The mechanical properties of CrB2 are better than MoB2, because CrB2 has low ultrasonic attenuation comparison t h a n MoB2. The comparison of calculated ultrasonic parameters with available theoretical/experimental physical parameters gives information about classification of these compounds.

Computations of Ultrasonic Parameters in Alloys

The ultrasonic properties like ultrasonic attenuation, sound velocity in the hexagonal alloys have been studied along unique axis at room temperature. The second- and third-order elastic constants (SOEC & TOEC) have been calculated for these alloys using Lennard-Jones potential. The velocities and have minima and maxima, respectively, at 45° with unique axis of the crystal, while increases with the angle from unique axis. The inconsistent behaviour of angle-dependent velocities is associated to the action of second-order elastic constants. Debye average sound velocities of these alloys are increasing with the angle and has maximum at 55° with unique axis at room temperature. Hence, when a sound wave travels at 55° with unique axis of these alloys, then the average sound velocity is found to be maximum. The mechanical and ultrasonic properties of these alloys will be better than pure Zr and Sn due to their high SOEC and ultrasonic velocity and low ultrasonic attenuation. The comparison of calculated ultrasonic parameters with available theoretical/experimental physical parameters gives information about classification of these alloys.

Acoustic Wave Propagation in Nanocrystalline RuCo Alloys

The ultrasonic properties like elastic constant, ultrasonic velocity in the hexagonal structured nanocrystalline RuCo alloys have been studied along unique axis at room temperature. The second and third order elastic constants (SOEC & TOEC) have been calculated for these alloys using Lennard-Jones potential. The orientation dependent ultrasonic velocity has been also evaluated to study the anisotropic behaviour of these alloys. The velocities VL and VS1 have minima and maxima, respectively at 45° with unique axis of the crystal, while VS2 increases with the angle from unique axis. The inconsistent behaviour of angle-dependent velocities is associated to the action of second order elastic constants. Debye average ultrasonic velocities of these alloys are increasing with the angle and has maximum at 55° with unique axis at room temperature. Hence, when a ultrasonic wave travels at 55° with unique axis of these alloys, then the average ultrasonic velocity is found to be maximum. Elastic constants and density are mainly the affecting factor for anomalous behaviour of ultrasonic velocity in these alloys. The mechanical and ultrasonic properties of Co0.75Ru0.25 alloy will be better than the other compounds due to their high SOEC, ultrasonic velocity and low ultrasonic attenuation. Co0.75Ru0.25 alloy is more suitable for industrial and other uses, as it has the highest elastic constants and lowest ultrasonic attenuation in comparison to other of these alloys. The results of this investigation are discussed in correlation with other known thermophysical properties.

エラストマー膜を介した電子パッケージの繰返しドライコンタクト超音波イメージング(J01-2 微細接続信頼性,J01 エレクトロニクス実装における熱制御および信頼性評価)

Dry-contact ultrasonic technique, which realizes the ultrasonic imaging without getting a sample wet, is a useful method for the inspection of electronic packages. In this study, we transmit high frequency ultrasound into the acrylic resin targets via four kinds of elastomer membranes with stability, and high durability, and select a membrane for cyclic ultrasonic imaging under a dry-contact condition. For recording high quality acoustic images, the membrane must satisfy the low ultrasonic attenuation and high acoustic coupling at the membrane/sample interface. Finally, we perform the cyclic ultrasonic imaging of an electronic package via the selected membrane, and repeatedly visualize the delamination in the package.

Temperature-stabilized wide-band ultrasonic delay line

The low ultrasonic attenuation of fused quartz in the very high frequency range makes it attractive for an ultrasonic delay line. However, the temperature instability restricts its application. A method of stabilizing the delay time based on the properties of a positive temperature coefficient resistor that is used simultaneously as a temperature sensor and a regulator is discussed. This new type of temperature regulator improves the temperature coefficient of the delay time from 85 ppm/°C to 8 ppm/°C. A temperature-stabilized wide-band delay line has been fabricated for high definition television. A wide-band frequency response is obtained by using LiNbO3 transducers and new type bonding adhesion which is stiffened by irradiation of ultraviolet rays. The design of the delay line, which has a midband frequency of 45 MHz, a band width of 50 MHz, and a delay time of 29.55 ms, is presented and experimental results are also presented.