Underground Imaging Method Using Magnified Cross-Correlation Analysis

Self Cite

We propose a method for the reconstruction of internal cracks using time of flight (TOF) of longitudinal waves. Since the longitudinal wave is the fastest elastic wave, it is possible to reconstruct cracks using a matrix method with apparent sound velocities calculated from the TOF. This method can neglect mode transformation and other waves because the first wave received is always the longitudinal wave. In addition, this method has the potential to be free from a blind sector and to detect the cracks precisely, because it is a transmission method and uses time domain analysis. We simulate crack detection using the transmission-line matrix (TLM) method. This proposed method detects cracks regardless of their location, direction, and number. It was also possible to detect the cracks when their length was smaller than the wavelength or when the billet had some error in its shape. This technique is expected to be useful for ultrasonic testing.

Section: Measurement Using Tof Of the Longitudinal Wavesmentioning

confidence: 99%

Detection of Internal Cracks in Square Billets Using Time of Flight of Longitudinal Waves

Mitsui¹,

Mizutani²,

Wakatsuki³

2009

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“…[126][127][128][129]132,133,[191][192][193][194][195][196][197][198] In addition, buried objects and the distribution of soil properties have been visualized as examples of underground measurements. 143,185,[199][200][201][202][203][204][205][206][207] …”

Section: Transmittermentioning

confidence: 99%

Introduction of measurement techniques in ultrasonic electronics: Basic principles and recent trends

Mizutani¹,

Wakatsuki²,

Ebihara³

2016

Self Cite

Measurementthe act of measuring physical properties that we performhas the potential to contribute to the successful advancement of sciences and society. To open doors in physics and other sciences, various measurement methods and related applications have been developed, and ultrasound has remained a useful probe, power source, and interesting measurement object for the past two centuries. In this paper, we first summarize the basic principles of ultrasound from the viewpoint of measurement techniques for readers who just have started studying or are interested in the field of ultrasonic electronics. Moreover, we also introduce recent studiesultrasonic properties of materials, measurement techniques, piezoelectric devices, nonlinear acoustics, biomedical ultrasound, and ocean acousticsand their trends related to measurement techniques in ultrasonic electronics to provide some ideas for related applications.

“…The proposed method of estimating DOA has high tolerance to the effect of reverberation and can be applied to the measurement of the difference in the time of flights. [20][21][22][23][24][25][26][27][28][29][30] This paper consists of five sections. In x2, we describe the algorithmic procedure of the proposed signal processing.…”

Section: Introductionmentioning

confidence: 99%

Direction of Arrival Estimation Based on Delayed-Sum Method in Reverberation Environment

Zempo¹,

Ebihara

Mizutani

2012

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High resolution far ultraviolet (12W2000,4) spectra of 17 cool giant and supergiant stars have been obtained using the IUE satellite of ESA, NASA and UK. We have measured the line intensities, wavelengths and widths of approximately 200 EUV emission lines in these spectra, using a least squares gaussian fitting technique. Line identification has been obtained in about one third of the cases. The measured values are organized in a database in order to facilitate updating and investigation of interrelations with stellar atmospheric parameters.The observations include lines from C I. C 11, C IV, S I, 0 I, 0 IV, Si 11, Si IV, N V, A1 111. Fe I1 and Mg 11. These lines are mostly formed by radiative processes in the extremely rarefied plasma in the outer stellar atmospheres, and occasionally involve highly excited energy levels of the atoms and ions. The temperature of formation ranges from about 5 x lo' to IO5 K, corresponding to different depth levels in the atmosphere, and the lines serve as a valuable tool for probing the physical conditions in these regions. We may also get new information on atomic processes that take place under conditions that are never duplicated in the laboratory. The present data may therefore give important contributions both to astrophysics and to atomic physics.