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laser doppler vibrometer

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https://www.readbyqxmd.com/read/28666703/a-comparative-study-of-med-el-fmt-attachment-to-the-long-process-of-the-incus-in-intact-middle-ears-and-its-attachment-to-disarticulated-stapes-head
#1
Tao Chen, Liu-Jie Ren, Dong-Ming Yin, Jia Li, Lin Yang, Pei-Dong Dai, Tian-Yu Zhang
The Vibrant Soundbridge(©) (VSB) active middle-ear implant provides an effective treatment for mild-to-severe sensorineural hearing loss in the case of normal middle ear anatomy and mixed hearing loss in middle ear malformation. The VSB floating mass transducer (FMT), with proper couplers, can be installed on various structures of the ossicular chain, e.g., the short and long process of the incus, the stapes head, and the stapes footplate. A long process (LP) coupler is most commonly used for FMT attachment to the long process of the incus with intact ossicular chain, while CliP and Bell couplers are two standardized and reliable methods for FMT attachment to the stapes head with missing incus and malleus...
June 23, 2017: Hearing Research
https://www.readbyqxmd.com/read/28657955/the-hannover-coupler-controlled-static-prestress-in-round-window-stimulation-with-the-floating-mass-transducer
#2
Mathias Müller, Rolf Salcher, Thomas Lenarz, Hannes Maier
INTRODUCTION: Stimulation of the cochlear round window (RW) with the floating mass transducer (FMT) still suffers from large variation in clinical outcomes. Beside the geometric mismatch between RW and FMT diameter that is a known limiting factor in achieving optimal coupling between actuator and RW membrane, the applied static force between FMT and RW is usually undefined. In this study, the feasibility and efficacy of a specially designed FMT coupler permitting application of static preloads to the RW membrane to optimize FMT-RW coupling was investigated...
June 27, 2017: Otology & Neurotology
https://www.readbyqxmd.com/read/28601531/sheep-as-a-large-animal-ear-model-middle-ear-ossicular-velocities-and-intracochlear-sound-pressure
#3
Dominik Péus, Ivo Dobrev, Lukas Prochazka, Konrad Thoele, Adrian Dalbert, Andreas Boss, Nicolas Newcomb, Rudolf Probst, Christof Röösli, Jae Hoon Sim, Alexander Huber, Flurin Pfiffner
Animals are frequently used for the development and testing of new hearing devices. Dimensions of the middle ear and cochlea differ significantly between humans and commonly used animals, such as rodents or cats. The sheep cochlea is anatomically more like the human cochlea in size and number of turns. This study investigated the middle-ear ossicular velocities and intracochlear sound pressure (ICSP) in sheep temporal bones, with the aim of characterizing the sheep as an experimental model for implantable hearing devices...
August 2017: Hearing Research
https://www.readbyqxmd.com/read/28515236/resonance-frequencies-of-honeybee-apis-mellifera-wings
#4
Christopher J Clark, Andrew M Mountcastle, Emily Mistick, Damian O Elias
During flight, insect wings bend and twist under the influence of aerodynamic and inertial forces. We tested whether wing resonance of honeybees (Apis mellifera) matches the wingbeat frequency, against the 'stiff element' hypothesis that the wing's first longitudinal mode exceeds the wingbeat frequency. Six bees were immobilized with their right wing pair outspread, and stimulated with a shaker while the normal modes were recorded with a Scanning Doppler Laser Vibrometer. The lowest normal mode of the wings was the first longitudinal bending mode, and at 602±145 Hz, greater than the wingbeat frequency of 234 Hz±13...
May 17, 2017: Journal of Experimental Biology
https://www.readbyqxmd.com/read/28481267/inkjet-printed-membrane-for-a-capacitive-acoustic-sensor-development-and-characterization-using-laser-vibrometer
#5
Rubaiyet Iftekharul Haque, Erick Ogam, Patrick Benaben, Xavier Boddaert
This paper describes the fabrication process and the method to determine the membrane tension and defects of an inkjet-printed circular diaphragm. The membrane tension is an important parameter to design and fabricate an acoustic sensor and resonator with the highest sensitivity and selectivity over a determined range of frequency. During this work, the diaphragms are fabricated by inkjet printing of conductive silver ink on pre-strained Mylar thin films, and the membrane tension is determined using the resonant frequency obtained from its measured surface velocity response to an acoustic excitation...
May 6, 2017: Sensors
https://www.readbyqxmd.com/read/28372141/optical-imaging-of-propagating-mach-cones-in-water-using-refracto-vibrometry
#6
Nathan R Huber, Thomas M Huber, Matthew T Huber
Refracto-vibrometry was used to optically image propagating Mach cones in water. These Mach cones were produced by ultrasonic longitudinal and shear waves traveling through submerged 12.7 mm diameter metal cylinders. Full-field videos of the propagating wave fronts were obtained using refracto-vibrometry. A laser Doppler vibrometer, directed at a retroreflective surface, sampled time-varying water density at numerous scan points. Wave speeds were determined from the Mach cone apex angles; the measured longitudinal and shear wave speeds in steel (6060 ± 170 m/s and 3310 ± 110 m/s, respectively) and beryllium (12 400 ± 700 m/s and 8100 ± 500 m/s) agreed with published values...
March 2017: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/28320655/a-study-on-the-effects-of-release-area-on-the-quality-factor-of-contour-mode-resonators-by-laser-doppler-vibrometry
#7
Brian Gibson, Kamala Qalandar, Cristian Cassella, Gianluca Piazza, Kimberly L Foster
Through the use of a laser Doppler vibrometer, it is shown that a 31% variation in quality factor can occur due to the effect of undercutting of the device layers outside of the anchors of a 220-MHz aluminum nitride contour-mode resonator. This undercutting is a result of the isotropic etch process used to release the device from the substrate. This paper shows that the variation in Q is a function of the release distance, L , between the active region of the resonator and the edge of this released region. This paper also determined a design modification that eliminated this issue and achieved a Q of 3048, which is independent of L ...
May 2017: IEEE Transactions on Ultrasonics, Ferroelectrics, and Frequency Control
https://www.readbyqxmd.com/read/28253676/time-reversal-focusing-of-elastic-waves-in-plates-for-an-educational-demonstration
#8
Christopher Heaton, Brian E Anderson, Sarah M Young
The purpose of this research is to develop a visual demonstration of time reversal focusing of vibrations in a thin plate. Various plate materials are tested to provide optimal conditions for time reversal focusing. Specifically, the reverberation time in each plate and the vibration coupling efficiency from a shaker to the plate are quantified to illustrate why a given plate provides the best spatially confined focus as well as the highest focal amplitude possible. A single vibration speaker and a scanning laser Doppler vibrometer (SLDV) are used to provide the time reversal focusing...
February 2017: Journal of the Acoustical Society of America
https://www.readbyqxmd.com/read/28231638/comparison-of-the-shock-absorption-capacities-of-different-mouthguards
#9
Melina Simonetta Bochnig, Min-Jung Oh, Theresa Nagel, Fred Ziegler, Paul-Georg Jost-Brinkmann
BACKGROUND/AIMS: In this in vitro study, the protective qualities of different mouthguard types were examined during small hard object collisions. The aim was to investigate inconclusive aspects of hard inserts, nylon nets, and air spaces as reinforcements in the anterior region and the protection qualities of ethylene vinyl acetate (EVA). MATERIALS AND METHODS: Five different mouthguards with a labial thickness between 2 mm and 11 mm made of materials of varying stiffness were investigated...
February 23, 2017: Dental Traumatology: Official Publication of International Association for Dental Traumatology
https://www.readbyqxmd.com/read/28079680/middle-ear-sound-transmission-under-normal-damaged-repaired-and-reconstructed-conditions
#10
Wei Dong, Ying Tian, Xin Gao, Timothy T K Jung
HYPOTHESIS: We hypothesize that current clinical treatment strategies for the disarticulated or eroded incus have the effect of combining the incus and stapes of the human middle ear (ME) into one rigid structure, which, while capable of adequately transmitting lower-frequency sounds, fails for higher frequencies. BACKGROUND: ME damage causes conductive hearing loss (CHL) and while great progress has been made in repairing or reconstructing damaged MEs, the outcomes are often far from ideal...
April 2017: Otology & Neurotology
https://www.readbyqxmd.com/read/28024609/mesenchymal-stem-cell-laden-hybrid-scaffold-for-regenerating-subacute-tympanic-membrane-perforation
#11
Chul Ho Jang, SeungHyun Ahn, Jae Whi Lee, Byeong Ha Lee, Hyeongjin Lee, GeunHyung Kim
Tympanic membrane (TM) perforation is one of the most common otology complications. To date, there has not been reported TM regeneration using bioprinted scaffold. The purpose of this study was to evaluate the efficacy and feasibility of bioprinted polycaprolactone/collagen/alginate-mesenchymal stem cell (PCAMSC) scaffolds for the regeneration of subacute TM perforation. Sprague-Dawley rats were used in an animal model of subacute TM perforation. In the experimental group (n=7), bioprinted 3D PCAMSC scaffold was placed on the perforation...
March 1, 2017: Materials Science & Engineering. C, Materials for Biological Applications
https://www.readbyqxmd.com/read/27857289/use-of-photoacoustic-excitation-and-laser-vibrometry-to-remotely-detect-trace-explosives
#12
C M Wynn, R W Haupt, J H Doherty, R R Kunz, W Bai, G Diebold
In this paper, we examine a laser-based approach to remotely initiate, measure, and differentiate acoustic and vibrational emissions from trace quantities of explosive materials against their environment. Using a pulsed ultraviolet laser (266 nm), we induce a significant (>100  Pa) photoacoustic response from small quantities of military-grade explosives. The photoacoustic signal, with frequencies predominantly between 100 and 500 kHz, is detected remotely via a wideband laser Doppler vibrometer. This two-laser system can be used to rapidly detect and discriminate explosives from ordinary background materials, which have significantly weaker photoacoustic response...
November 10, 2016: Applied Optics
https://www.readbyqxmd.com/read/27631663/intracranial-pressure-and-promontory-vibration-with-soft-tissue-stimulation-in-cadaveric-human-whole-heads
#13
Christof Roosli, Ivo Dobrev, Jae Hoon Sim, Rahel Gerig, Flurin Pfiffner, Stefan Stenfelt, Alexander M Huber
HYPOTHESIS: Intracranial pressure and skull vibrations are correlated and depend on the stimulation position and frequency. BACKGROUND: A hearing sensation can be elicited by vibratory stimulation on the skin covered skull, or by stimulation on soft tissue such as the neck. It is not fully understood whether different stimulation sites induce the skull vibrations responsible for the perception or whether other transmission pathways are dominant. The aim of this study was to assess the correlation between intracranial pressure and skull vibration measured on the promontory for stimulation to different sites on the head...
October 2016: Otology & Neurotology
https://www.readbyqxmd.com/read/27594098/a-tri-coil-bellows-type-round-window-transducer-with-improved-frequency-characteristics-for-middle-ear-implants
#14
Dong Ho Shin, Ki Woong Seong, Sunil Puria, Kyu-Yup Lee, Jin-Ho Cho
A number of methods to drive the round window (RW) using a floating mass transducer (FMT) have been reported. This method has attracted attention because the FMT is relatively easy to implant in the RW niche. However, the use of an FMT to drive the RW has been proven to produce low outputs at frequencies below approximately 1 kHz. In this study, a new tri-coil bellows-type transducer (TCBT), which has excellent low frequency output and is easy to implant, is proposed. To design the frequency characteristics of the TCBT, mechanical and electrical simulations were performed, and then a comparative analysis was conducted between a floating mass type transducer (like the FMT) and a fixed type transducer (like the TCBT)...
November 2016: Hearing Research
https://www.readbyqxmd.com/read/27557194/photo-vibrational-spectroscopy-of-solid-and-liquid-chemicals-using-laser-doppler-vibrometer
#15
Qi Hu, Jacob Song Kiat Lim, Huan Liu, Yu Fu
Photoacoustic/photothermal spectroscopy is an established technique for trace detection of chemicals and explosives. However, prior sample preparation is required and the analysis is conducted in a sealed space with a high-sensitivity microphone or a piezo sensor coupled with a lock-in amplifier, limiting the technique to applications in a laboratory environment. Due to the aforementioned requirements, traditionally this technique may not be suitable for defense and security applications where the detection of explosives or hazardous chemicals is required in an open environment at a safe standoff distance...
August 22, 2016: Optics Express
https://www.readbyqxmd.com/read/27475551/development-of-an-fpga-based-multipoint-laser-pyroshock-measurement-system-for-explosive-bolts
#16
Syed Haider Abbas, Jae-Kyeong Jang, Jung-Ryul Lee, Zaeill Kim
Pyroshock can cause failure to the objective of an aerospace structure by damaging its sensitive electronic equipment, which is responsible for performing decisive operations. A pyroshock is the high intensity shock wave that is generated when a pyrotechnic device is explosively triggered to separate, release, or activate structural subsystems of an aerospace architecture. Pyroshock measurement plays an important role in experimental simulations to understand the characteristics of pyroshock on the host structure...
July 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27473506/acoustic-input-impedance-of-the-avian-inner-ear-measured-in-ostrich-struthio-camelus
#17
Pieter G G Muyshondt, Peter Aerts, Joris J J Dirckx
In both mammals and birds, the mechanical behavior of the middle ear structures is affected by the mechanical impedance of the inner ear. In this study, the aim was to quantify the acoustic impedance of the avian inner ear in the ostrich, which allows us to determine the effect on columellar vibrations and middle ear power flow in future studies. To determine the inner ear impedance, vibrations of the columella were measured for both the quasi-static and acoustic stimulus frequencies. In the frequency range of 0...
September 2016: Hearing Research
https://www.readbyqxmd.com/read/27461115/vibration-transmission-through-sheet-webs-of-hobo-spiders-eratigena-agrestis-and-tangle-webs-of-western-black-widow-spiders-latrodectus-hesperus
#18
Samantha Vibert, Catherine Scott, Gerhard Gries
Web-building spiders construct their own vibratory signaling environments. Web architecture should affect signal design, and vice versa, such that vibratory signals are transmitted with a minimum of attenuation and degradation. However, the web is the medium through which a spider senses both vibratory signals from courting males and cues produced by captured prey. Moreover, webs function not only in vibration transmission, but also in defense from predators and the elements. These multiple functions may impose conflicting selection pressures on web design...
November 2016: Journal of Comparative Physiology. A, Neuroethology, Sensory, Neural, and Behavioral Physiology
https://www.readbyqxmd.com/read/27428980/nanomechanical-pyrolytic-carbon-resonators-novel-fabrication-method-and-characterization-of-mechanical-properties
#19
Maksymilian Kurek, Frederik K Larsen, Peter E Larsen, Silvan Schmid, Anja Boisen, Stephan S Keller
Micro- and nanomechanical string resonators, which essentially are highly stressed bridges, are of particular interest for micro- and nanomechanical sensing because they exhibit resonant behavior with exceptionally high quality factors. Here, we fabricated and characterized nanomechanical pyrolytic carbon resonators (strings and cantilevers) obtained through pyrolysis of photoresist precursors. The developed fabrication process consists of only three processing steps: photolithography, dry etching and pyrolysis...
2016: Sensors
https://www.readbyqxmd.com/read/27403641/wave-mode-extraction-from-multimodal-wave-signals-in-an-orthotropic-composite-plate
#20
M Ratassepp, Z Fan, K Lasn
In this paper the post-processing procedure based on the mode orthogonality is applied to extract individual waveforms at a composite plate edge from multimodal signals. To obtain the amplitudes of individual modes, numerically predicted modal through-thickness stress and displacement field values are used in the orthogonality relation. The performance of the mode extraction technique is evaluated by processing signals obtained from Finite Element (FE) modeling and experimental measurements. The propagation of the overlapping wave packets of Lamb modes S0 and A0 is considered along the fiber direction and perpendicular to that direction...
September 2016: Ultrasonics
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