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Ultrasonic Guided Waves

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ISBN: 9783039282982 9783039282999 Year: Pages: 376 DOI: 10.3390/books978-3-03928-299-9 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Technology (General) --- General and Civil Engineering
Added to DOAB on : 2020-04-07 23:07:09
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The propagation of ultrasonic guided waves in solids is an important area of scientific inquiry, primarily due to their practical applications for nondestructive characterization of materials, such as nondestructive inspection, quality assurance testing, structural health monitoring, and providing a material state awareness. This Special Issue of Applied Sciences covers all aspects of ultrasonic guided waves (e.g., phased array transducers, meta-materials to control wave propagation characteristics, scattering, attenuation, and signal processing techniques) from the perspective of modeling, simulation, laboratory experiments, or field testing. In order to fully utilize ultrasonic guided waves for these applications, it is necessary to have a firm grasp of their requisite characteristics, which include that they are multimodal, dispersive, and are comprised of unique displacement profiles through the thickness of the waveguide.

Keywords

electromagnetic wave --- group velocity --- time-frequency domain reflectometry --- dispersive medium --- ultrasonic guided wave --- nondestructive testing --- square steel bar --- non-detection zone --- surface flaw --- Rayleigh wave --- scattering --- modified BEM --- reconstruction --- adhesive joint --- single lap joint --- non-destructive testing --- damage identification --- Lamb waves --- scanning laser vibrometry --- signal processing --- ultrasonic guided waves --- axial transmission --- ultrasonic guided waves --- fiber optics --- fiber Bragg grating --- nondestructive testing --- structural health monitoring --- pipe inspection --- partial wave method --- slowness curves --- lamb wave --- stoneley wave --- mode sorting --- acoustic leakage --- rayleigh wave --- surface waves --- elastodynamics --- guided waves --- lamb wave --- dispersion curves --- phase velocity --- group velocity --- signal processing --- SH0 mode --- circumferential scanning --- synthetic aperture focusing --- exploding reflector model --- Lamb wave --- local wavenumber --- air-coupled transducer --- wavenumber domain filtering --- hybrid and non-contact system --- signal processing --- SNR --- split-spectrum processing --- ultrasonic guided waves --- signal processing --- defect detection --- spatial domain --- array analysis --- pipeline inspection --- ultrasonic guided waves (UGWs) --- metamaterial --- resonator --- low-frequency --- lamb wave --- adaptive filtering --- leaky normalized mean square --- ultrasonic guided waves --- pipeline inspection --- SNR enhancement --- signal processing --- guided wave --- multi-wire cable --- wave structure --- contact acoustic nonlinearity --- energy transfer --- rail --- ultrasonic guided wave --- semi-analytical finite element --- single mode extraction algorithm --- defect location --- signal processing --- defect detection --- torsional wave --- power spectrum --- sliding window --- pipeline inspection --- ultrasonic guided-waves (UGWs) --- magnetostrictive patch transducer --- shear mode --- soft magnetic patch --- dynamic magnetic field optimization --- signal strength enhancement --- acoustic emission --- nondestructive testing --- leakage location --- fault diagnosis --- n/a --- lamb waves --- composite --- ultrasonic testing --- numerical modelling --- pressure vessels

Optical MEMS

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ISBN: 9783039213030 9783039213047 Year: Pages: 172 DOI: 10.3390/books978-3-03921-304-7 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Technology (General) --- General and Civil Engineering
Added to DOAB on : 2019-12-09 11:49:15
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Optical microelectromechanical systems (MEMS), microoptoelectromechanical systems (MOEMS), or optical microsystems are devices or systems that interact with light through actuation or sensing at a micro- or millimeter scale. Optical MEMS have had enormous commercial success in projectors, displays, and fiberoptic communications. The best-known example is Texas Instruments’ digital micromirror devices (DMDs). The development of optical MEMS was impeded seriously by the Telecom Bubble in 2000. Fortunately, DMDs grew their market size even in that economy downturn. Meanwhile, in the last one and half decade, the optical MEMS market has been slowly but steadily recovering. During this time, the major technological change was the shift of thin-film polysilicon microstructures to single-crystal–silicon microsructures. Especially in the last few years, cloud data centers are demanding large-port optical cross connects (OXCs) and autonomous driving looks for miniature LiDAR, and virtual reality/augmented reality (VR/AR) demands tiny optical scanners. This is a new wave of opportunities for optical MEMS. Furthermore, several research institutes around the world have been developing MOEMS devices for extreme applications (very fine tailoring of light beam in terms of phase, intensity, or wavelength) and/or extreme environments (vacuum, cryogenic temperatures) for many years. Accordingly, this Special Issue seeks to showcase research papers, short communications, and review articles that focus on (1) novel design, fabrication, control, and modeling of optical MEMS devices based on all kinds of actuation/sensing mechanisms; and (2) new developments of applying optical MEMS devices of any kind in consumer electronics, optical communications, industry, biology, medicine, agriculture, physics, astronomy, space, or defense.

Keywords

scanning micromirror --- electromagnetic actuator --- angle sensor --- flame retardant 4 (FR4) --- variable optical attenuator (VOA) --- wavelength dependent loss (WDL) --- polarization dependent loss (PDL) --- micro-electro-mechanical systems (MEMS) --- tunable fiber laser --- echelle grating --- DMD chip --- MEMS scanning micromirror --- fringe projection --- laser stripe scanning --- quality map --- large reflection variations --- 3D measurement --- laser stripe width --- vibration noise --- MLSSP --- MEMS scanning mirror --- wavefront sensing --- digital micromirror device --- ocular aberrations --- dual-mode liquid-crystal (LC) device --- infrared Fabry–Perot (FP) filtering --- LC micro-lenses controlled electrically --- spectrometer --- infrared --- digital micromirror device (DMD) --- signal-to-noise ratio (SNR) --- stray light --- programmable spectral filter --- digital micromirror device --- optical switch --- microscanner --- input shaping --- open-loop control --- quasistatic actuation --- residual oscillation --- usable scan range --- higher-order modes --- resonant MEMS scanner --- electrostatic --- parametric resonance --- NIR fluorescence --- intraoperative microscope --- 2D Lissajous --- fluorescence confocal --- metasurface --- metalens --- field of view (FOV) --- achromatic --- Huygens’ metalens --- bio-optical imaging --- optical coherence tomography --- confocal --- two-photon --- spectrometer --- MEMS mirror --- electrothermal bimorph --- Cu/W bimorph --- electrothermal actuation --- reliability --- n/a

Ultrasound B-mode Imaging: Beamforming and Image Formation Techniques

Authors: --- ---
ISBN: 9783039211999 9783039212002 Year: Pages: 146 DOI: 10.3390/books978-3-03921-200-2 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Technology (General) --- General and Civil Engineering
Added to DOAB on : 2019-12-09 11:49:15
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Ultrasound medical imaging stands out among the other diagnostic imaging modalities for its patient-friendliness, high temporal resolution, low cost, and absence of ionizing radiation. On the other hand, it may still suffer from limited detail level, low signal-to-noise ratio, and narrow field-of-view. In the last decade, new beamforming and image reconstruction techniques have emerged which aim at improving resolution, contrast, and clutter suppression, especially in difficult-to-image patients. Nevertheless, achieving a higher image quality is of the utmost importance in diagnostic ultrasound medical imaging, and further developments are still indispensable. From this point of view, a crucial role can be played by novel beamforming techniques as well as by non-conventional image formation techniques (e.g., advanced transmission strategies, and compounding, coded, and harmonic imaging). This Special Issue includes novel contributions on both ultrasound beamforming and image formation techniques, particularly addressed at improving B-mode image quality and related diagnostic content. This indeed represents a hot topic in the ultrasound imaging community, and further active research in this field is expected, where many challenges still persist.

Optical Communications and Networking: Prospects in Industrial Applications

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ISBN: 9783039282586 9783039282593 Year: Pages: 132 DOI: 10.3390/books978-3-03928-259-3 Language: English
Publisher: MDPI - Multidisciplinary Digital Publishing Institute
Subject: Technology (General) --- General and Civil Engineering
Added to DOAB on : 2020-04-07 23:07:09
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In the past few decades, the optical communication industry has explored multiple degrees of freedom of the photon, such as time, wavelength, amplitude, phase, polarization, and space, to significantly reduce the cost/bit of data transmission by increasing the capacity per fiber through multiplexing technology and by reducing the size and power through electronic and photonic integration. This book aims to explore the latest advancements in this industry, including the technologies in devices, systems, and network levels with applications from short-reach chip-to-chip interconnections to long-haul backbone communications at the trans-oceanic distance.

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