Read by QxMD icon Read


Moez Ben Boubaker, Donald Picard, Carl Duchesne, Jayson Tessier, Houshang Alamdari, Mario Fafard
This paper reports on the application of an acousto-ultrasonic (AU) scheme for the inspection of industrial-size carbon anode blocks used in the production of primary aluminium by the Hall-Héroult process. A frequency-modulated wave is used to excite the anode blocks at multiple points. The collected attenuated AU signals are decomposed using the Discrete Wavelet Transform (DTW) after which vectors of features are calculated. Principal Component Analysis (PCA) is utilized to cluster the AU responses of the anodes...
May 17, 2018: Ultrasonics
Shuzeng Zhang, Xiongbing Li, Hyunjo Jeong, Hongwei Hu
Angle beam wedge transducers are widely used in nonlinear Rayleigh wave experiments as they can generate Rayleigh wave easily and produce high intensity nonlinear waves for detection. When such a transducer is used, the spurious harmonics (source nonlinearity) and wave diffraction may occur and will affect the measurement results, so it is essential to fully understand its acoustic nature. This paper experimentally investigates the nonlinear Rayleigh wave beam fields generated and received by angle beam wedge transducers, in which the theoretical predictions are based on the acoustic model developed previously for angle beam wedge transducers [S...
May 12, 2018: Ultrasonics
Julia Mariglia, Shadab Momin, Imogen R Coe, Raffi Karshafian
Ultrasonically-stimulated microbubbles enhance the therapeutic effects of various chemotherapy drugs. However, the application of ultrasound and microbubbles (USMB) for enhancing the therapeutic effect of nucleoside analogs, which are used as front-line treatments in a range of cancers, and its underlying mechanism is not well understood. This study investigated the effect of gemcitabine, a nucleoside analog drug, in combination with USMB in increasing cell cytotoxicity relative to either treatment alone in BxPC3 pancreatic cancer cells...
May 5, 2018: Ultrasonics
See Yenn Chong, Michael D Todd
Numerous Lamb wave dispersion curve estimation methods have been developed to support damage detection and localization strategies in non-destructive evaluation/structural health monitoring (NDE/SHM) applications. In this paper, the covariance matrix is used to extract features from an ultrasonic wavefield imaging (UWI) scan in order to estimate the phase and group velocities of S0 and A0 modes. A laser ultrasonic interrogation method based on a Q-switched laser scanning system was used to interrogate full-field ultrasonic signals in a 2-mm aluminum plate at five different frequencies...
May 1, 2018: Ultrasonics
Kazuyuki Dei, Brett Byram
Previously, we introduced a model-based beamforming algorithm to suppress ultrasound imaging artifacts caused by clutter sources, such as reverberation and off-axis scattering. We refer to this method as aperture domain model image reconstruction (ADMIRE). In this study, we evaluated the algorithm's limitations and ability to suppress off-axis energy using Field II-based simulations, experimental phantoms and in vivo data acquired by a Verasonics ultrasound system with a curvilinear transducer (C5-2). We compared image quality derived from a standard delay-and-sum (DAS) beamformer, DAS with coherence factor (CF) weighting, ADMIRE and ADMIRE plus CF weighting...
April 25, 2018: Ultrasonics
Ho-Wuk Kim, Fuh-Gwo Yuan
Waveforms received by sensors resulting from multiple wavepaths overlap and are hard to interpret. Because of this difficulty, they are usually intentionally ignored, thereby only the first arrival of wave mode being used for damage localization. This article proposes an imaging algorithm for damage localization by incorporating multiple wavepaths using piezoelectric wafers affixed on a metallic plate. Matching pursuit (MP) algorithm to enhance image quality is adopted for separating each wave packet individually...
April 24, 2018: Ultrasonics
Tao Liu, Jun Lin, Yanjin Guan, Zhendong Xie, Lihua Zhu, Jiqiang Zhai
The technology of ultrasonic vibration assisted plastic forming possesses a great many merits, such as reducing the deformation resistance and friction, as well as improving the surface quality of parts. In this study, the ultrasonic vibration assisted compression tests were carried out on pure titanium in order to improve its formability. The results indicating that the ultrasonic vibration had no effort on elastic deformation, and the temperature of material only increased by 6 °C after compression with applying the ultrasonic vibration...
April 24, 2018: Ultrasonics
Hongchen Miao, Qiang Huan, Faxin Li, Guozheng Kang
Focusing the incident wave beam along a given direction is very useful in guided wave based structural health monitoring (SHM), as it will not only save input power but also simplify the interpretation of signals. Although the fundamental shear horizontal (SH0 ) wave is of practical importance in SHM due to its non-dispersive characteristics so far there have been very limited transducers which can control the radiation patterns of SH0 wave. In this work, a variable-frequency bidirectional SH0 wave piezoelectric transducer (BSH-PT) is proposed, which consists of two rectangular face-shear (d24 ) PZT wafers...
April 24, 2018: Ultrasonics
Zichuan Fan, Wentao Jiang, William M D Wright
This paper describes a completely non-contact ultrasonic method of gas flow metering using air-coupled leaky Lamb waves. To show proof of principle, a simplified representation of gas flow in a duct, comprising two separated thin isotropic plates with a gas flowing between them, has been modelled and investigated experimentally. An airborne compression wave emitted from an air-coupled capacitive ultrasonic transducer excited a leaky Lamb wave in the first plate in a non-contact manner. The leakage of this Lamb wave crossed the gas flow at an angle between the two plates as a compression wave, and excited a leaky Lamb wave in the second plate...
April 23, 2018: Ultrasonics
Hideyuki Nomura, Hideo Adachi, Tomoo Kamakura
When using high-frequency (HF) ultrasound in sonography, attenuation due to the viscosity of the medium limits the available imaging depth, and strong reflection and scattering from hard tissue, such as bone, render biological diagnosis very difficult. In order to resolve these problems, the feasibility of low-frequency (LF) parametric ultrasound imaging with high directivity was explored in the present study. A pulse compression technique was applied to chirp-modulated parametric ultrasound waves in the frequency band of 100-500 kHz generated from modulated primary ultrasound waves with a center frequency of 2...
April 23, 2018: Ultrasonics
Aashit Kumar Jaiswal, Pramod Kumar Yadawa, R R Yadav
The elastic and ultrasonic properties of the hexagonal intermetallic CeCuGe ternary compound have been evaluated along unique axis at room temperature. Higher order elastic constants have been calculated for CeCuGe compound using Lennard-Jones interaction potential model. The ultrasonic velocity, Debye average velocity, thermal relaxation time and acoustic coupling constant are evaluated along unique axis of the crystal and the temperature dependent ultrasonic velocities are evaluated along different angles with unique axis of the crystal...
April 23, 2018: Ultrasonics
Jianjun Wu, Zhifeng Tang, Fuzai Lü, Keji Yang
As essential components of a high-speed railway system, switch rails can be easily damaged by sophisticated operating conditions. Therefore, precise online detection for switch rails is necessary. Methods based on ultrasonic guided waves are ideal candidates for structural integrity of the switch rails, which are natural waveguides with irregular cross-sections. However, energy decentralization in the wave propagation severely restricts detectability. Phased array systems have been developed and implemented to steer and focus acoustic energy in waveguides of ordinary cross-sections such as pipes and plates...
April 11, 2018: Ultrasonics
Aziz Asadollahi, Lev Khazanovich
The emergence of ultrasonic dry point contact (DPC) transducers that emit horizontal shear waves has enabled efficient collection of high-quality data in the context of a nondestructive evaluation of concrete structures. This offers an opportunity to improve the quality of evaluation by adapting advanced imaging techniques. Reverse time migration (RTM) is a simulation-based reconstruction technique that offers advantages over conventional methods, such as the synthetic aperture focusing technique. RTM is capable of imaging boundaries and interfaces with steep slopes and the bottom boundaries of inclusions and defects...
April 11, 2018: Ultrasonics
Cuixiang Pei, Siqi Zhao, Tianhao Liu, Zhenmao Chen
In this work, a new non-contact and coupling-free ultrasound method with measuring Rayleigh wave polarization (RWP) by electromagnetic acoustic transducers (EMATs) is applied for plastic strain measurement, which can provide a very promising alternative and reference-free ultrasonic testing technique with high spatial resolution. Two specially designed EMAT receivers are developed to measure the polarization of Rayleigh wave generated by an enhanced meander-line-coil EMAT. The change in RWP due to the plastic strain has been successfully measured...
April 11, 2018: Ultrasonics
Vitaly B Voloshinov, Dmitriy L Porokhovnichenko, Evgeniy A Dyakonov
The paper proposes a design of acousto-optic cell applying backward collinear interaction and acoustic mode transformation in a KRS-5 crystal. This cell may serve as an acousto-optic tunable filter for far-infrared spectral range and is able to operate both with collimated optical beams and with divergent beams forming images. The problem of acoustic mode transformation by wave reflection from the crystal facet away from symmetry planes has been solved. Polarization properties of the backward collinear interaction in optically isotropic media are discussed...
April 10, 2018: Ultrasonics
Rungroj Jintamethasawat, Won-Mean Lee, Paul L Carson, Fong Ming Hooi, J Brian Fowlkes, Mitchell M Goodsitt, Richard Sampson, Thomas F Wenisch, Siyuan Wei, Jian Zhou, Chaitali Chakrabarti, Oliver D Kripfgans
We have investigated limited angle transmission tomography to estimate speed of sound (SOS) distributions for breast cancer detection. That requires both accurate delineations of major tissues, in this case by segmentation of prior B-mode images, and calibration of the relative positions of the opposed transducers. Experimental sensitivity evaluation of the reconstructions with respect to segmentation and calibration errors is difficult with our current system. Therefore, parametric studies of SOS errors in our bent-ray reconstructions were simulated...
April 7, 2018: Ultrasonics
Shuai Yang, Ying Liu
Liquid crystal nematic elastomers are one kind of smart anisotropic and viscoelastic solids simultaneously combing the properties of rubber and liquid crystals, which is thermal sensitivity. In this paper, the wave dispersion in a liquid crystal nematic elastomer porous phononic crystal subjected to an external thermal stimulus is theoretically investigated. Firstly, an energy function is proposed to determine thermo-induced deformation in NE periodic structures. Based on this function, thermo-induced band variation in liquid crystal nematic elastomer porous phononic crystals is investigated in detail...
April 5, 2018: Ultrasonics
Yanlong Wei, Gao Wang, Yubin Gao, Zhengguang Liu, Lin Xu, Miao Tian, Dongfang Yuan, Haiping Ren, Hanchang Zhou, Lu Yang, Xueshun Shi, Zhaoqian Xiao
Iridium-rhodium is generally applied as a thermocouple material, with max operating temperature about 2150 °C. In this study, a ultrasonic temperature measurement system was designed by using Iridium-rhodium (60%Ir-40%Rh) alloy as an acoustic waveguide sensor material, and the system was preliminarily tested in a high-temperature oxidation environment. The result of ultrasonic temperature measurement shows that this system can indeed work stably in high-temperature oxidation environments. The relationship between temperature and delay time of ultrasonic thermometry up to 2200 °C was illustrated...
April 3, 2018: Ultrasonics
Qiaozhen Zhang, Jiaqi Guo, Peng Qin, Gongbin Tang, Benfeng Zhang, Ken-Ya Hashimoto, Tao Han, Ping Li, Yumei Wen
This paper proposes a general finite element method (FEM)-based wavenumber domain analysis (WDA) to calculate scattering characteristics of surface acoustic wave (SAW) on arbitrary piezoelectric substrates. We add a damping loss mechanism (DLM) to the SAW injection port to avoid interferences from the incident and backscattered modes. After checking the validity of the proposed method, we calculate and study Sezawa mode scattering using a small number of electrodes on the ScAlN/3CSiC structure for demonstration...
March 31, 2018: Ultrasonics
Natalya F Naumenko
Multilayered substrates, including thin plates of LiTaO3 (LT) bonded to silicon (Si) or glass wafers either directly or via intermediate layers, were numerically investigated as potential materials for surface acoustic wave (SAW) resonators with high quality (Q)-factor required for the next generation of mobile communication systems. The propagation velocities and electromechanical coupling coefficients of shear horizontally (SH) polarized acoustic waves were estimated as functions of LT orientation and thicknesses of all layers in LT/Si, LT/SiO2 /Si, LT/glass, LT/AlN/glass and structures with several pairs of SiO2 /AlN layers between LT and the glass wafer...
March 31, 2018: Ultrasonics
Fetch more papers »
Fetching more papers... Fetching...
Read by QxMD. Sign in or create an account to discover new knowledge that matter to you.
Remove bar
Read by QxMD icon Read

Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"