keyword
MENU ▼
Read by QxMD icon Read
search

Laser doppler vibrometry

keyword
https://www.readbyqxmd.com/read/27857289/use-of-photoacoustic-excitation-and-laser-vibrometry-to-remotely-detect-trace-explosives
#1
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/27802716/approaching-attometer-laser-vibrometry
#2
C Rembe, L Kadner, M Giesen
The heterodyne two-beam interferometer has been proven to be the optimal solution for laser-Doppler vibrometry (LDV) regarding accuracy and signal robustness. The theoretical resolution limit for a two-beam interferometer of laser class 3R (up to 5 mW visible measurement-light) is in the regime of a few femtometer per square-root Hertz and well suited to study vibrations in microstructures. However, some new applications of radio-frequency microelectromechanical (RF-MEM) resonators, nanostructures, and surface-nano-defect detection require resolutions beyond that limit...
October 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27802700/response-measurement-by-laser-doppler-vibrometry-in-vibration-qualification-tests-with-non-gaussian-random-excitation
#3
M Troncossi, R Di Sante, A Rivola
In the field of vibration qualification testing, random excitations are typically imposed on the tested system in terms of a power spectral density (PSD) profile. This is the one of the most popular ways to control the shaker or slip table for durability tests. However, these excitations (and the corresponding system responses) exhibit a Gaussian probability distribution, whereas not all real-life excitations are Gaussian, causing the response to be also non-Gaussian. In order to introduce non-Gaussian peaks, a further parameter, i...
October 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27802696/features-of-the-non-contact-carotid-pressure-waveform-cardiac-and-vascular-dynamics-during-rebreathing
#4
S Casaccia, E J Sirevaag, E J Richter, J A O'Sullivan, L Scalise, J W Rohrbaugh
This report amplifies and extends prior descriptions of the use of laser Doppler vibrometry (LDV) as a method for assessing cardiovascular activity, on a non-contact basis. A rebreathing task (n = 35 healthy individuals) was used to elicit multiple effects associated with changes in autonomic drive as well as blood gases including hypercapnia. The LDV pulse was obtained from two sites overlying the carotid artery, separated by 40 mm. A robust pulse signal was obtained from both sites, in accord with the well-described changes in carotid diameter over the blood pressure cycle...
October 2016: Review of Scientific Instruments
https://www.readbyqxmd.com/read/27749749/a-new-intraoperative-real-time-monitoring-system-for-reconstructive-middle-ear-surgery-an-experimental-and-clinical-feasibility-study
#5
Thomas Zahnert, Marie-Luise Metasch, Hannes Seidler, Matthias Bornitz, Nicoloz Lasurashvili, Marcus Neudert
HYPOTHESIS: Electromagnetical excitation of ossicular vibration is suitable for middle ear transmission measurements in the experimental and clinical setting. Thereby, it can be used as a real-time monitoring system for quality control in ossiculoplasty. BACKGROUND: Positioning and coupling of middle ear prosthesis are a precondition for good postoperative hearing results, but at the same time completely dependent upon the surgeon's subjective judgment during surgery...
December 2016: Otology & Neurotology
https://www.readbyqxmd.com/read/27683000/auditory-mechanics-in-a-bush-cricket-direct-evidence-of-dual-sound-inputs-in-the-pressure-difference-receiver
#6
Thorin Jonsson, Fernando Montealegre-Z, Carl D Soulsbury, Kate A Robson Brown, Daniel Robert
The ear of the bush-cricket, Copiphora gorgonensis, consists of a system of paired eardrums (tympana) on each foreleg. In these insects, the ear is backed by an air-filled tube, the acoustic trachea (AT), which transfers sound from the prothoracic acoustic spiracle to the internal side of the eardrums. Both surfaces of the eardrums of this auditory system are exposed to sound, making it a directionally sensitive pressure difference receiver. A key feature of the AT is its capacity to reduce the velocity of sound propagation and alter the acoustic driving forces at the tympanum...
September 2016: Journal of the Royal Society, Interface
https://www.readbyqxmd.com/read/27610377/differential-intracochlear-sound-pressure-measurements-in-human-temporal-bones-with-an-off-the-shelf-sensor
#7
Martin Grossöhmichen, Rolf Salcher, Klaus Püschel, Thomas Lenarz, Hannes Maier
The standard method to determine the output level of acoustic and mechanical stimulation to the inner ear is measurement of vibration response of the stapes in human cadaveric temporal bones (TBs) by laser Doppler vibrometry. However, this method is reliable only if the intact ossicular chain is stimulated. For other stimulation modes an alternative method is needed. The differential intracochlear sound pressure between scala vestibuli (SV) and scala tympani (ST) is assumed to correlate with excitation. Using a custom-made pressure sensor it has been successfully measured and used to determine the output level of acoustic and mechanical stimulation...
2016: BioMed Research International
https://www.readbyqxmd.com/read/27579835/a-preliminary-investigation-of-the-air-bone-gap-changes-in-intracochlear-sound-pressure-with-air-and-bone-conducted-stimuli-after-cochlear-implantation
#8
Renee M Banakis Hartl, Jameson K Mattingly, Nathaniel T Greene, Herman A Jenkins, Stephen P Cass, Daniel J Tollin
HYPOTHESIS: A cochlear implant electrode within the cochlea contributes to the air-bone gap (ABG) component of postoperative changes in residual hearing after electrode insertion. BACKGROUND: Preservation of residual hearing after cochlear implantation has gained importance as simultaneous electric-acoustic stimulation allows for improved speech outcomes. Postoperative loss of residual hearing has previously been attributed to sensorineural changes; however, presence of increased postoperative ABG remains unexplained and could result in part from altered cochlear mechanics...
October 2016: Otology & Neurotology
https://www.readbyqxmd.com/read/27546727/development-of-a-novel-completely-in-the-canal-direct-drive-hearing-device
#9
Hamid R Djalilian, Hossein Mahboubi, Yarah M Haidar, Peyton Paulick, Mark W Merlo, Mark Bachman
OBJECTIVES/HYPOTHESIS: To develop a novel completely-in-the-canal device capable of directly driving the tympanic membrane (TM) and ossicular chain from the ear canal. STUDY DESIGN: Development and feasibility study. METHODS: A voice coil actuator design was developed to drive the TM. Bench testing of the device using laser Doppler vibrometry (LDV) and sound recording was performed. Temporal bone studies using LDV were performed using different designs of the contact tip-TM interface to find the most efficient method of sound transmission...
August 22, 2016: Laryngoscope
https://www.readbyqxmd.com/read/27500399/direct-acoustic-stimulation-at-the-lateral-canal-an-alternative-route-to-the-inner-ear
#10
Nicolas Verhaert, Joris Walraevens, Christian Desloovere, Jan Wouters, Jean-Marc Gérard
Severe to profound mixed hearing loss is associated with hearing rehabilitation difficulties. Recently, promising results for speech understanding were obtained with a direct acoustic cochlear implant (DACI). The surgical implantation of a DACI with standard coupling through a stapedotomy can however be regarded as challenging. Therefore, in this experimental study, the feasibility of direct acoustic stimulation was investigated at an anatomically and surgically more accessible inner ear site. DACI stimulation of the intact, blue-lined and opened lateral semicircular canal (LC) was investigated and compared with standard oval window (OW) coupling...
2016: PloS One
https://www.readbyqxmd.com/read/27496538/controlled-exploration-of-the-effects-of-conductive-hearing-loss-on-wideband-acoustic-immittance-in-human-cadaveric-preparations
#11
Gabrielle R Merchant, Saumil N Merchant, John J Rosowski, Hideko Heidi Nakajima
Current clinical practice cannot distinguish, with any degree of certainty, the multiple pathologies that produce conductive hearing loss in patients with an intact tympanic membrane and a well-aerated middle ear without exploratory surgery. The lack of an effective non-surgical diagnostic procedure leads to unnecessary surgery and limits the accuracy of information available during pre-surgical consultations with the patient. A non-invasive measurement to determine the pathology responsible for a conductive hearing loss prior to surgery would be of great value...
August 3, 2016: Hearing Research
https://www.readbyqxmd.com/read/27490002/motion-of-tympanic-membrane-in-guinea-pig-otitis-media-model-measured-by-scanning-laser-doppler-vibrometry
#12
Xuelin Wang, Xiying Guan, Mario Pineda, Rong Z Gan
Otitis media (OM) is an inflammatory or infectious disease of the middle ear. Acute otitis media (AOM) and otitis media with effusion (OME) are the two major types of OM. However, the tympanic membrane (TM) motion differences induced by AOM and OME have not been quantified in animal models in the literature. In this study, the guinea pig AOM and OME models were created by transbullar injection of Streptococcus pneumoniae type 3 and lipopolysaccharide, respectively. To explore the effects of OM on the entire TM vibration, the measurements of full-field TM motions were performed in the AOM, OME and untreated control ears by using scanning laser Doppler vibrometry (SLDV)...
September 2016: Hearing Research
https://www.readbyqxmd.com/read/27312415/anatomical-basis-of-dynamic-modulation-of-tympanic-tension-in-the-water-monitor-lizard-varanus-salvator
#13
Dawei Han, Bruce A Young
Amphibious vertebrates, such as the water monitor (Varanus salvator), require anatomical and/or neural specializations to cope with pressure changes on the tympanic membrane when transiting between air and water. V. salvator has internally coupled ears which are distinguished by (patent) anatomical conduits through the skull linking the middle ear cavities on both sides of the head. We describe a small skeletal muscle in V. salvator which inserts onto the middle ear ossicle and the tympanic membrane. Laser doppler vibrometry demonstrates that contraction of this muscle both increases the vibrational velocity of the tympanic membrane and changes the waveform pattern of the tympanic displacement...
September 2016: Anatomical Record: Advances in Integrative Anatomy and Evolutionary Biology
https://www.readbyqxmd.com/read/27244585/a-non-contact-approach-for-pwv-detection-application-in-a-clinical-setting
#14
Adriaan Campo, Hilde Heuten, Inge Goovaerts, Guy Ennekens, Christiaan Vrints, Joris Dirckx
A need for screening methods for arteriosclerosis led to the development of several approaches to measure pulse wave velocity (PWV) being indicative of arterial stiffness. Carotid-femoral PWV (cfPWV) can be measured between common carotid artery (CCA) and femoral artery (FA) displaying the physiologically important stiffness of the conduit arteries. However, this measurement approach has several disadvantages, and a local PWV-measurement of CCA-stiffness has been proposed as an alternative in the past. In the presented pilot study, laser Doppler vibrometry (LDV) is used to measure PWV locally in the CCA (PWVLDV) in 48 patients aged between 48 and 70, with known atherosclerotic arterial disease: stabilized coronary artery disease (CAD), cerebro-vascular disease (CVD) or peripheral artery disease (PAD)...
July 2016: Physiological Measurement
https://www.readbyqxmd.com/read/27209198/low-frequency-eardrum-directionality-in-the-barn-owl-induced-by-sound-transmission-through-the-interaural-canal
#15
Lutz Kettler, Jakob Christensen-Dalsgaard, Ole Næsbye Larsen, Hermann Wagner
The middle ears of birds are typically connected by interaural cavities that form a cranial canal. Eardrums coupled in this manner may function as pressure difference receivers rather than pressure receivers. Hereby, the eardrum vibrations become inherently directional. The barn owl also has a large interaural canal, but its role in barn owl hearing and specifically in sound localization has been controversial so far. We discuss here existing data and the role of the interaural canal in this species and add a new dataset obtained by laser Doppler vibrometry in a free-field setting...
May 21, 2016: Biological Cybernetics
https://www.readbyqxmd.com/read/27176393/experimental-study-of-three-wave-interactions-among-capillary-gravity-surface-waves
#16
Florence Haudin, Annette Cazaubiel, Luc Deike, Timothée Jamin, Eric Falcon, Michael Berhanu
In propagating wave systems, three- or four-wave resonant interactions constitute a classical nonlinear mechanism exchanging energy between the different scales. Here we investigate three-wave interactions for gravity-capillary surface waves in a closed laboratory tank. We generate two crossing wave trains and we study their interaction. Using two optical methods, a local one (laser doppler vibrometry) and a spatiotemporal one (diffusive light photography), a third wave of smaller amplitude is detected, verifying the three-wave resonance conditions in frequency and in wave number...
April 2016: Physical Review. E
https://www.readbyqxmd.com/read/27139310/influence-of-stimulation-position-on-the-sensitivity-for-bone-conduction-hearing-aids-without-skin-penetration
#17
Ivo Dobrev, Stefan Stenfelt, Christof Röösli, Lucy Bolt, Flurin Pfiffner, Rahel Gerig, Alexander Huber, Jae Hoon Sim
OBJECTIVE: This study explores the influence of stimulation position on bone conduction (BC) hearing sensitivity with a BC transducer attached using a headband. DESIGN: (1) The cochlear promontory motion was measured in cadaver heads using laser Doppler vibrometry while seven different positions around the pinna were stimulated using a bone anchored hearing aid transducer attached using a headband. (2) The BC hearing thresholds were measured in human subjects, with the bone vibrator Radioear B71 attached to the same seven stimulation positions...
August 2016: International Journal of Audiology
https://www.readbyqxmd.com/read/27103102/laser-doppler-vibrometry-as-a-noncontact-method-to-detect-various-degrees-of-atrioventricular-block-a-feasibility-study
#18
Armin Luik, Laura Mignanelli, Kristian Kroschel, Claus Schmitt, Christian Rembe, Lorenzo Scalise
BACKGROUND: The vibrocardiography (VBCG) is a laser-based technique to monitor the heart rhythm without any contact to the body. The aim of this study was to evaluate whether the VBCG is able to detect the vibration patterns of the atria. METHODS: Simultaneous recordings of the ECG and VBCG in two cohorts were evaluated. RESULTS: The VBCG delivered a robust vibration pattern of the atrial contraction. A reliable determination of the interval and the different stages of an atrioventricular block was possible...
May 2016: Future Cardiology
https://www.readbyqxmd.com/read/27093023/loads-and-coupling-modalities-influence-the-performance-of-the-floating-mass-transducer-as-a-round-window-driver
#19
Antoniu Oreste Gostian, David Pazen, Magdalene Ortmann, Andreas Anagiotos, David Schwarz, Karl Bernd Hüttenbrink, Dirk Beutner
HYPOTHESIS: High loads forcing the floating mass transducer (FMT) of a single active middle ear implant toward the round window membrane (RWM) affect the backward stimulation of the cochlea. BACKGROUND: Various factors influence the backward stimulation of the cochlea. We investigated the effects of various loads applied to the FMT together with different coupling techniques at the fully exposed RWM on the vibration transmission. METHODS: Experimental study on temporal bones with the FMT linked to a load cell mounted on a translation stage moving it against the fully exposed RWM with increasing loads up to 200 mN by itself, with interposed perichondrium, cartilage or connected to the round window coupler...
June 2016: Otology & Neurotology
https://www.readbyqxmd.com/read/27090282/methodology-for-intraoperative-laser-doppler-vibrometry-measurements-of-ossicular-chain-reconstruction
#20
Jacek Sokołowski, Magdalena Lachowska, Robert Bartoszewicz, Kazimierz Niemczyk
OBJECTIVES: Despite the increasing number of research concerning the applications of the Laser Doppler Vibrometry (LDV) in medicine, its usefulness is still under discussion. The aim of this study is to present a methodology developed in our Department for the LDV intraoperative assessment of ossicular chain reconstruction. METHODS: Ten patients who underwent "second look" tympanoplasty were involved in the study. The measurements of the acoustic conductivity of the middle ear were performed using the LDV system...
June 2016: Clinical and Experimental Otorhinolaryngology
keyword
keyword
95664
1
2
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"