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Showing 1 to 20 of 60 for “"ultrasonic waves"”.
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New Developments on Quantitative Imaging Using Ultrasonic Waves
… ways of processing the radiofrequency ultrasonic data. Two notable approaches are acoustic tomography and backscatter coefficient analysis. However, these techniques suffer from limitations that keep them from becoming widely used clinical tools. This dissertation presents several …
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Ultrasonic waves in solids radiated from an elliptically loaded source
Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2000.
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Finite element modeling of transient ultrasonic waves in linear viscoelastic media
… based finite element method for modeling pulsed ultrasonic waves in linear, homogeneous viscoelastic media is developed that does not require storage of the complete time history of displacement at every node. This is accomplished by modeling the stress relaxation moduli as discrete or continuous …
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The observation of phase state and temperature using noninvasive ultrasonic waves.
… investigates the hypothesis that the use of ultrasonic signals and the resulting time of flight and intensity of the high-frequency sound wave may be used to identify a material undergoing a phase change within a confined vessel. A wax melting experiment within a confined chamber has been …
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Monitoring Corrosion of Rebar Embedded in Mortar Using Guided Ultrasonic Waves
… in reinforced concrete, and guided mechanical waves have also been presented.
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Characterization and deterioration detection of portland cement concrete using ultrasonic waves
… and to detect chloride presence in PCC using ultrasonic waves. The experimental program was initiated to investigate the effect of water to cement (w/c) ratio, aggregate type, and air entrainn1ent on measured ultrasonic wave velocity and signal energy. Three w/c ratios (0.35, 0.45, and 0.55) …
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A One-Dimensional Approximation for the Attenuation of Ultrasonic Waves in A Solid
Made available in DSpace on 2014-12-10T17:25:40Z (GMT). No. of bitstreams: 1 6808022.pdf: 1181038 bytes, checksum: 00394be5ff002d69f21f2aff313d30ea (MD5) Previous issue date: 1967
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Investigation of Planar Channeling Radiation on Diamond and Quartz Crystals at Electron Energies between 14 and 34 MeV and Probing the Influence of Ultrasonic Waves on Channeling Radiation
The first measurements of CR at the Radiation source ELBE of the Forschungszentrum Dresden-Rossendorf have been performed in the fall of 2003, where the most important attempt for an application of CR in radiobiological research was the optimization of its yield and spectral line width as well. …
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Phenomena in the propagation of ultrasonic vibrations in nickel wire
… the signal, was used to study the propagation of ultrasonic waves in nickel wire. In particular, the origin of often observed anomalous waves in nickel wire was investigated. A possible explanation of an aspect of the phenomenon was devised. During continuing investigation of the phenomenon of …
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Ultrasonic nondestructive evaluation and imaging of defects in reinforced cementitious materials
… of structures. Among many other NDE techniques, ultrasonic methods play a prominent role in the both quantitative and qualitative assessment of discontinuities in reinforced cementitious materials. Due to the heterogeneous nature of concrete, ultrasonic waves are highly scattered and attenuated, …
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Radiative transfer of ultrasound
… used to model the multiple scattering of diffuse ultrasonic waves in two types of random media. The first type is an isotropic, homogeneous medium containing randomly oriented, randomly located scatterers. The scatterers are assumed to be uncorrelated. This assumption allows an equation of …
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Nondestructive evaluation of composite rods using ultrasonic wave propagation
… of different materials) using theoretical ultrasonic NDE. In anticipation of the high elastic moduli of the rods (relative to many metals) along their longitudinal axes, a one-dimensional wave propagation analysis will be conducted. By analyzing the propagation of ultrasonic waves in …
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The classification of slurries and other suspensions using ultrasonic techniques
The attenuation of ultrasonic waves travelling through a liquid containing a suspension of solids is highly dependent on frequency. At low frequencies, where the wavelength is long compared to the particle size, the particles move with the wave with some phase lag which gives rise to a loss …
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Theory of ultrasonic diffraction by damage developed in thin laminated composites
… provides a general theory of the diffraction of ultrasonic waves. The theory is then used to find the apparent attenuation which would result if certain damage states (transverse cracks and delaminations) are introduced into a graphite/epoxy laminate through which the ultrasonic wave passes. and …
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Pulsed-Laser Ultrasound Generation in Fiber-Reinforced Composite Material
A laser-based ultrasonic technique using a pulsed laser for stimulating ultrasonic waves in fiber-reinforced composite materials is the subject of investigation. For convenience, the material is chosen to be homogeneous transversely isotropic. The study is strictly limited to the laser power …
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Lattice modeling of ultrasonic nondestructive evaluation of attenuating materials
… nondestructive evaluation. When subjected to ultrasonic waves, nanocomposites often exhibit attenuation that is an order of magnitude higher than that of carbon fiber reinforced polymeric composites. Thus, an accurate model of ultrasonic wave propagation in nanocomposites as well as several …
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Random Actuation Pattern Optimization by Genetic Algorithm for Ultrasonic Structural Health Monitoring of Plates
… monitoring. The point excitations generate ultrasonic waves in both isotropic and anisotropic materials that can be effective in diagnosing structural defects. The formed ultrasonic waves can constructively interfere and send out an intense wave beam to a predetermined target. The …
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Ultrasonically Assisted Single Screw Extrusion, Film Blowing and Film Casting of LLDPE/Clay and PA6/Clay Nanocomposites
… of this study was to investigate the effect of ultrasonic treatment on the dispersion of modified clay particles in LLDPE and PA6 matrices and the final properties of nanocomposites. LLDPE and PA6 are two polymers that are widely used in packaging industry. Blown and cast films were manufactured …
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