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Sample records for 45-mhz needle transducer

  1. Angled-focused 45 MHz PMN-PT single element transducer for intravascular ultrasound imaging.

    PubMed

    Yoon, Sangpil; Williams, Jay; Kang, Bong Jin; Yoon, Changhan; Cabrera-Munoz, Nestor; Jeong, Jong Seob; Lee, Sang Goo; Shung, K Kirk; Kim, Hyung Ham

    2015-06-01

    A transducer with an angled and focused aperture for intravascular ultrasound imaging has been developed. The acoustic stack for the angled-focused transducer was made of PMN-PT single crystal with one matching layer, one protective coating layer, and a highly damped backing layer. It was then press-focused to a desired focal length and inserted into a thin needle housing with an angled tip. A transducer with an angled and unfocused aperture was also made, following the same fabrication procedure, to compare the performance of the two transducers. The focused and unfocused transducers were tested to measure their center frequencies, bandwidths, and spatial resolutions. Lateral resolution of the angled-focused transducer (AFT) improved more than two times compared to that of the angled-unfocused transducer (AUT). A tissue-mimicking phantom in water and a rabbit aorta tissue sample in rabbit blood were scanned using AFT and AUT. Imaging with AFT offered improved contrast, over imaging with AUT, of the tissue-mimicking phantom and the rabbit aorta tissue sample by 23 dB and 8 dB, respectively. The results show that AFT has strong potential to provide morphological and pathological information of coronary arteries with high resolution and high contrast.

  2. Angled-focused 45 MHz PMN-PT single element transducer for intravascular ultrasound imaging

    PubMed Central

    Yoon, Sangpil; Williams, Jay; Kang, Bong Jin; Yoon, Changhan; Cabrera-Munoz, Nestor; Jeong, Jong Seob; Lee, Sang Goo; Shung, K. Kirk; Kim, Hyung Ham

    2015-01-01

    A transducer with an angled and focused aperture for intravascular ultrasound imaging has been developed. The acoustic stack for the angled-focused transducer was made of PMN-PT single crystal with one matching layer, one protective coating layer, and a highly damped backing layer. It was then press-focused to a desired focal length and inserted into a thin needle housing with an angled tip. A transducer with an angled and unfocused aperture was also made, following the same fabrication procedure, to compare the performance of the two transducers. The focused and unfocused transducers were tested to measure their center frequencies, bandwidths, and spatial resolutions. Lateral resolution of the angled-focused transducer (AFT) improved more than two times compared to that of the angled-unfocused transducer (AUT). A tissue-mimicking phantom in water and a rabbit aorta tissue sample in rabbit blood were scanned using AFT and AUT. Imaging with AFT offered improved contrast, over imaging with AUT, of the tissue-mimicking phantom and the rabbit aorta tissue sample by 23 dB and 8 dB, respectively. The results show that AFT has strong potential to provide morphological and pathological information of coronary arteries with high resolution and high contrast. PMID:25914443

  3. Focused high frequency needle transducer for ultrasonic imaging and trapping

    NASA Astrophysics Data System (ADS)

    Hsu, Hsiu-Sheng; Zheng, Fan; Li, Ying; Lee, Changyang; Zhou, Qifa; Kirk Shung, K.

    2012-07-01

    A miniature focused needle transducer (<1 mm) was fabricated using the press-focusing technique. The measured pulse-echo waveform showed the transducer had center frequency of 57.5 MHz with 54% bandwidth and 14 dB insertion loss. To evaluate the performance of this type of transducer, invitro ultrasonic biomicroscopy imaging on the rabbit eye was obtained. Moreover, a single beam acoustic trapping experiment was performed using this transducer. Trapping of targeted particle size smaller than the ultrasonic wavelength was observed. Potential applications of these devices include minimally invasive measurements of retinal blood flow and single beam acoustic trapping of microparticles.

  4. Dual-element needle transducer for intravascular ultrasound imaging

    PubMed Central

    Yoon, Sangpil; Kim, Min Gon; Williams, Jay A.; Yoon, Changhan; Kang, Bong Jin; Cabrera-Munoz, Nestor; Shung, K. Kirk; Kim, Hyung Ham

    2015-01-01

    Abstract. A dual-element needle transducer for intravascular ultrasound imaging has been developed. A low-frequency element and a high-frequency element were integrated into one device to obtain images which conveyed both low- and high-frequency information from a single scan. The low-frequency element with a center frequency of 48 MHz was fabricated from the single crystal form of lead magnesium niobate-lead titanate solid solution with two matching layers (MLs) and the high frequency element with a center frequency of 152 MHz was fabricated from lithium niobate with one ML. The measured axial and lateral resolutions were 27 and 122  μm, respectively, for the low-frequency element, and 14 and 40  μm, respectively, for the high-frequency element. The performance of the dual-element needle transducer was validated by imaging a tissue-mimicking phantom with lesion-mimicking area, and ex vivo rabbit aortas in water and rabbit whole blood. The results suggest that a low-frequency element effectively provides depth resolved images of the whole vessel and its adjacent tissue, and a high-frequency element visualizes detailed structure near the surface of the lumen wall in the presence of blood within the lumen. The advantages of a dual-element approach for intravascular imaging are also discussed. PMID:26158118

  5. Photoacoustic imaging of clinical metal needle by a LED light source integrated transducer

    NASA Astrophysics Data System (ADS)

    Agano, Toshitaka; Sato, Naoto; Nakatsuka, Hitoshi; Kitagawa, Kazuo; Hanaoka, Takamitsu; Morisono, Koji; Shigeta, Yusuke; Tanaka, Chizuyo

    2016-03-01

    We have achieved penetration depth of 30mm by photoacoustic imaging system using LED light source integrated transducer to image a clinical metal needle inserted into a tissue mimicking phantom. We developed the transducer that integrated near-infrared LED array light source, which was connected to a photoacoustic imaging system which drove LED array light source and controlled photoacoustic data acquisition process. Conventionally solid-state laser has been used as the light source for photoacoustic imaging system. Because LED is diffused light source, laser safety glasses is not necessary, also inflexible fibers are not used to guide light close to a transducer, and we integrated LED light source inside the transducer, which became compact and practical size for conventional ultrasound equipment users. We made LED light source unit as detachable to the transducer easily, so wave-length of light can be selectable by changing the LED light source unit.

  6. A 45-MHz continuum survey of the northern hemisphere

    NASA Astrophysics Data System (ADS)

    Maeda, K.; Alvarez, H.; Aparici, J.; May, J.; Reich, P.

    We present a 45-MHz continuum survey in the declination range of +5 to +65 degrees in sets of maps in galactic and equatorial coordinates (epoch 1950). The observations were made at 46.5 MHz with a circular filled array of the Japanese Middle and Upper Atmosphere Radar (MU Radar) located at Shigaraki, Japan. The radar array consists of 475 crossed 3-element Yagis arranged within a circle of 103 m diameter, with a the half-power beam width of 3.6 degrees. In order to calibrate the data from the MU radar we used the Chilean 45-MHz survey which was made with an array of size comparable with that of the MU radar. The data processing was performed at the Maipu Radio Observatory, University of Chile, and this process brought the data to 45 MHz. The final maps were obtained at the Max-Plank-Institut fur Radioastronomie, Germany, using of the NOD2 program package.

  7. PMN-PT single crystal, high-frequency ultrasonic needle transducers for pulsed-wave Doppler application.

    PubMed

    Zhou, Qifa; Xu, Xiaochen; Gottlieb, Emanuel J; Sun, Lei; Cannata, Jonathan M; Ameri, Hossein; Humayun, Mark S; Han, Pengdi; Shung, K Kirk

    2007-03-01

    High-frequency needle ultrasound transducers with an aperture size of 0.4 mm were fabricated using lead magnesium niobate-lead titanate (PMN-33% PT) as the active piezoelectric material. The active element was bonded to a conductive silver particle matching layer and a conductive epoxy backing through direct contact curing. An outer matching layer of parylene was formed by vapor deposition. The active element was housed within a polyimide tube and a 20-gauge needle housing. The magnitude and phase of the electrical impedance of the transducer were 47 omega and -38 degrees, respectively. The measured center frequency and -6 dB fractional bandwidth of the PMN-PT needle transducer were 44 MHz and 45%, respectively. The two-way insertion loss was approximately 15 dB. In vivo high-frequency, pulsed-wave Doppler patterns of blood flow in the posterior portion and in vitro ultrasonic backscatter microscope (UBM) images of the rabbit eye were obtained with the 44-MHz needle transducer.

  8. Measurements of attenuation coefficient for evaluating the hardness of a cataract lens by a high-frequency ultrasonic needle transducer

    NASA Astrophysics Data System (ADS)

    Huang, Chih-Chung; Chen, Ruimin; Tsui, Po-Hsiang; Zhou, Qifa; Humayun, Mark S.; Shung, K. Kirk

    2009-10-01

    A cataract is a clouding of the lens in the eye that affects vision. Phacoemulsification is the mostly common surgical method for treating cataracts, and determining that the optimal phacoemulsification energy is dependent on measuring the hardness of the lens. This study explored the use of an ultrasound needle transducer for invasive measurements of ultrasound attenuation coefficient to evaluate the hardness of the cataract lens. A 47 MHz high-frequency needle transducer with a diameter of 0.9 mm was fabricated by a polarized PMN-33%PT single crystal in the present study. The attenuation coefficients at different stages of an artificial porcine cataract lens were measured using the spectral shift approach. The hardness of the cataract lens was also evaluated by mechanical measurement of its elastic properties. The results demonstrated that the ultrasonic attenuation coefficient was increased from 0.048 ± 0.02 to 0.520 ± 0.06 dB mm-1 MHz-1 corresponding to an increase in Young's modulus from 6 ± 0.4 to 96 ± 6.2 kPa as the cataract further developed. In order to evaluate the feasibility of combining needle transducer and phacoemulsification probe for real-time measurement during cataract surgery, the needle transducer was mounted on the phacoemulsification probe for a vibration test. The results indicated that there was no apparent damage to the tip of the needle transducer and the pulse-echo test showed that a good performance in sensitivity was maintained after the vibration test.

  9. 3D Ultrasonic Needle Tracking with a 1.5D Transducer Array for Guidance of Fetal Interventions

    PubMed Central

    West, Simeon J.; Mari, Jean-Martial; Ourselin, Sebastien; David, Anna L.; Desjardins, Adrien E.

    2016-01-01

    Ultrasound image guidance is widely used in minimally invasive procedures, including fetal surgery. In this context, maintaining visibility of medical devices is a significant challenge. Needles and catheters can readily deviate from the ultrasound imaging plane as they are inserted. When the medical device tips are not visible, they can damage critical structures, with potentially profound consequences including loss of pregnancy. In this study, we performed 3D ultrasonic tracking of a needle using a novel probe with a 1.5D array of transducer elements that was driven by a commercial ultrasound system. A fiber-optic hydrophone integrated into the needle received transmissions from the probe, and data from this sensor was processed to estimate the position of the hydrophone tip in the coordinate space of the probe. Golay coding was used to increase the signal-to-noise (SNR). The relative tracking accuracy was better than 0.4 mm in all dimensions, as evaluated using a water phantom. To obtain a preliminary indication of the clinical potential of 3D ultrasonic needle tracking, an intravascular needle insertion was performed in an in vivo pregnant sheep model. The SNR values ranged from 12 to 16 at depths of 20 to 31 mm and at an insertion angle of 49° relative to the probe surface normal. The results of this study demonstrate that 3D ultrasonic needle tracking with a fiber-optic hydrophone sensor and a 1.5D array is feasible in clinically realistic environments. PMID:28111644

  10. Statistical characterization of the dynamic human body communication channel at 45 MHz.

    PubMed

    Nie, Zedong; Ma, Jingjing; Chen, Hong; Wang, Lei

    2013-01-01

    The dynamic human body communication (HBC) propagation channel at 45 MHz was statistical characterized in this paper. A large amount of measurement data has been gathered in practical environment with real activities -treadmill running at different speeds in a lab room. The received power between two lower legs was acquired from three volunteers, with more than 60,000 snap shot of data in total. The statistical analyses confirmed that the HBC propagation channel at 45 MHz followed the Gamma and Lognormal distributions at the slower (2 km/h and 4 km/h) and faster (6 km/h and 8 km/h) running activities, respectively. The channel is insensitive to body motion with the maximum average fade duration is 0.0413 s and the most averaging bad channel duration time being less than 60 ms with the percentage of the bad channel duration time being less than 4.35%.

  11. In vivo Sonothrombolysis of Ear Marginal Vein of Rabbits Monitored with High-frequency Ultrasound Needle Transducer

    PubMed Central

    Chen, Ruimin; Paeng, Dong-Guk; Lam, Kwok Ho; Zhou, Qifa; Shung, K. Kirk; Matsuoka, Naoki; Humayun, Mark S.

    2013-01-01

    Ultrasound (US) is known to enhance thrombolysis when thrombolytic agents and/or microbubbles are injected into the targeted vessels. In this research, high-intensity US (1 MHz, 7 W/cm2, 30 % duty cycle) was applied in vivo to the ear marginal vein of three rabbits which was occluded by either laser photothrombosis or thrombin, right after the injection of 0.3~0.6 cc of microbubbles (13 × 108 bubbles/ml of concentration) through the other ear vein without using any thrombolytic agent. To determine the effect of the sonothrombolysis, the blood flow velocity near the occlusion site in the vein was measured by a custom-made 40-MHz US needle transducer and its corresponding Doppler US system. The Doppler spectra show that the blood flow velocity recovered from total occlusion after three 10-minute high-intensity US treatments. Fluorescein angiography was employed to confirm the opening of the vessel occlusion. A control study of three rabbits with only the microbubble injection showed no recovery on the occlusion in 3 hours. The results show that the sonothrombolysis in the rabbit ear marginal vein can be achieved with microbubbles only. The results of cavitation measurements indicate that the mechanism of sonothrombolysis is probably due to the cavitation induced by the microbubbles. Without the need of applying any thrombolytic agent, high-intensity US has high potential for therapies targeting on small blood vessels. PMID:25356073

  12. Imaging of implant needles for real-time HDR-brachytherapy prostate treatment using biplane ultrasound transducers.

    PubMed

    Siebert, Frank-André; Hirt, Markus; Niehoff, Peter; Kovács, György

    2009-08-01

    Ultrasound imaging is becoming increasingly important in prostate brachytherapy. In high-dose-rate (HDR) real-time planning procedures the definition of the implant needles is often performed by transrectal ultrasound. This article describes absolute measurements of the visibility and accuracy of manual detection of implant needle tips and compares measurement results of different biplane ultrasound systems in transversal and longitudinal (i.e., sagittal) ultrasound modes. To obtain a fixed coordinate system and stable conditions the measurements were carried out in a water tank using a dedicated marker system. Needles were manually placed in the phantom until the observer decided by the real-time ultrasound image that the zero position was reached. A comparison of three different ultrasound systems yielded an offset between 0.8 and 3.1 mm for manual detection of the needle tip in ultrasound images by one observer. The direction of the offset was discovered to be in the proximal direction, i.e., the actual needle position was located more distally compared to the ultrasound-based definition. In the second part of the study, the ultrasound anisotropy of trocar implant needles is reported. It was shown that the integrated optical density in a region of interest around the needle tip changes with needle rotation. Three peaks were observed with a phase angle of 120 degrees. Peaks appear not only in transversal but also in longitudinal ultrasound images, with a phase shift of 60 degrees. The third section of this study shows results of observer dependent influences on needle tip detection in sagittal ultrasound images considering needle rotation. These experiments were carried out using the marker system in a water tank. The needle tip was placed exactly at the position z=0 mm. It was found that different users tend to differently interpret the same ultrasound images. The needle tip was manually detected five times in the ultrasound images by three experienced observers

  13. Analysis of Bromination of Ethylbenzene Using a 45 MHz NMR Spectrometer: An Undergraduate Organic Chemistry Laboratory Experiment

    ERIC Educational Resources Information Center

    Isaac-Lam, Meden F.

    2014-01-01

    A 45 MHz benchtop NMR spectrometer is used to identify the structures and determine the amount of 1-bromoethylbenzene and 1,1-dibromoethylbenzene produced from free-radical bromination of ethylbenzene. The experiment is designed for nonchemistry majors, specifically B.S. Biology students, in a predominantly undergraduate institution with…

  14. Real-time 3-d intracranial ultrasound with an endoscopic matrix array transducer.

    PubMed

    Light, Edward D; Mukundan, Srinivasan; Wolf, Patrick D; Smith, Stephen W

    2007-08-01

    A transducer originally designed for transesophageal echocardiography (TEE) was adapted for real-time volumetric endoscopic imaging of the brain. The transducer consists of a 36 x 36 array with an interelement spacing of 0.18 mm. There are 504 transmitting and 252 receive channels placed in a regular pattern in the array. The operating frequency is 4.5 MHz with a -6 dB bandwidth of 30%. The transducer is fabricated on a 10-layer flexible circuit from Microconnex (Snoqualmie, WA, USA). The purpose of this study is to evaluate the clinical feasibility of real-time 3-D intracranial ultrasound with this device. The Volumetrics Medical Imaging (Durham, NC, USA) 3-D scanner was used to obtain images in a canine model. A transcalvarial acoustic window was created under general anesthesia in the animal laboratory by placing a 10-mm burr hole in the high parietal calvarium of a 50-kg canine subject. The burr-hole was placed in a left parasagittal location to avoid the sagittal sinus, and the transducer was placed against the intact dura mater for ultrasound imaging. Images of the lateral ventricles were produced, including real-time 3-D guidance of a needle puncture of one ventricle. In a second canine subject, contrast-enhanced 3-D Doppler color flow images were made of the cerebral vessels including the complete Circle of Willis. Clinical applications may include real-time 3-D guidance of cerebrospinal fluid extraction from the lateral ventricles and bedside evaluation of critically ill patients where computed tomography and magnetic resonance imaging techniques are unavailable.

  15. Transducer characterization

    SciTech Connect

    Cross, B. T.; Eoff, J. M.; Schuetz, L. J.; Cunningham, K. R.

    1980-07-02

    This report has been prepared specifically for ultrasonic transducer users within the Nondestructive Testing Evaluation (NDE) community of the weapons complex. The purpose of the report is to establish an initial set of uniform procedures for measuring and recording transducer performance data, and to establish a common foundation on which more comprehensive transducer performance evaluations may be added as future transducer performance criteria expands. Transducer parameters and the problems with measuring them are discussed and procedures for measuring transducer performance are recommended with special precautionary notes regarding critical aspects of each measurement. An important consideration regarding the recommended procedures is the cost of implementation. There are two distinct needs for transducer performance characterization in the complex. Production oriented users need a quick, reliable means to check a transducer to ascertain its suitability for continued service. Development groups and the Transducer Center need a comprehensive characterization means to collect adequate data to evaluate theoretical concepts or to build exact replacement transducers. The instrumentation, equipment, and procedures recommended for monitoring production transducers are utilitarian and provide only that information needed to determine transducer condition.

  16. Piezoelectric transducer

    NASA Technical Reports Server (NTRS)

    Conragan, J.; Muller, R. S.

    1970-01-01

    Transducer consists of a hybrid thin film and a piezoelectric transistor that acts as a stress-sensitive device with built-in gain. It provides a stress/strain transducer that incorporates a signal amplification stage and sensor in a single package.

  17. Microinterferometer transducer

    DOEpatents

    Corey, III, Harry S.

    1979-01-01

    An air-bearing microinterferometer transducer is provided for increased accuracy, range and linearity over conventional displacement transducers. A microinterferometer system is housed within a small compartment of an air-bearing displacement transducer housing. A movable cube corner reflector of the interferometer is mounted to move with the displacement gauging probe of the transducer. The probe is disposed for axial displacement by means of an air-bearing. Light from a single frequency laser is directed into an interferometer system within the transducer housing by means of a self-focusing fiber optic cable to maintain light coherency. Separate fringe patterns are monitored by a pair of fiber optic cables which transmit the patterns to a detecting system. The detecting system includes a bidirectional counter which counts the light pattern fringes according to the direction of movement of the probe during a displacement gauging operation.

  18. Acoustic transducer

    DOEpatents

    Drumheller, Douglas S.

    2000-01-01

    An active acoustic transducer tool for use down-hole applications. The tool includes a single cylindrical mandrel including a shoulder defining the boundary of a narrowed portion over which is placed a sandwich-style piezoelectric tranducer assembly. The piezoelectric transducer assembly is prestressed by being placed in a thermal interference fit between the shoulder of the mandrel and the base of an anvil which is likewise positioned over the narrower portion of the mandrel. In the preferred embodiment, assembly of the tool is accomplished using a hydraulic jack to stretch the mandrel prior to emplacement of the cylindrical sandwich-style piezoelectric transducer assembly and anvil. After those elements are positioned and secured, the stretched mandrel is allowed to return substantially to its original (pre-stretch) dimensions with the result that the piezoelectric transducer elements are compressed between the anvil and the shoulder of the mandrel.

  19. Acoustic transducer

    DOEpatents

    Drumheller, D.S.

    1997-12-30

    An acoustic transducer is described comprising a one-piece hollow mandrel into the outer surface of which is formed a recess with sides perpendicular to the central axis of the mandrel and separated by a first distance and with a bottom parallel to the central axis and within which recess are a plurality of washer-shaped discs of a piezoelectric material and at least one disc of a temperature-compensating material with the discs being captured between the sides of the recess in a pre-stressed interference fit, typically at 2,000 psi of compressive stress. The transducer also includes a power supply and means to connect to a measurement device. The transducer is intended to be used for telemetry between a measurement device located downhole in an oil or gas well and the surface. The transducer is of an construction that is stronger with fewer joints that could leak fluids into the recess holding the piezoelectric elements than is found in previous acoustic transducers. 4 figs.

  20. Acoustic transducer

    DOEpatents

    Drumheller, Douglas S.

    1997-01-01

    An acoustic transducer comprising a one-piece hollow mandrel into the outer surface of which is formed a recess with sides perpendicular to the central axis of the mandrel and separated by a first distance and with a bottom parallel to the central axis and within which recess are a plurality of washer-shaped discs of a piezoelectric material and at least one disc of a temperature-compensating material with the discs being captured between the sides of the recess in a pre-stressed interference fit, typically at 2000 psi of compressive stress. The transducer also includes a power supply and means to connect to a measurement device. The transducer is intended to be used for telemetry between a measurement device located downhole in an oil or gas well and the surface. The transducer is of an construction that is stronger with fewer joints that could leak fluids into the recess holding the piezoelectric elements than is found in previous acoustic transducers.

  1. Ultrasonic transducer

    DOEpatents

    Taylor, Steven C.; Kraft, Nancy C.

    2007-03-13

    An ultrasonic transducer having an effective center frequency of about 42 MHz; a bandwidth of greater than 85% at 6 dB; a spherical focus of at least 0.5 inches in water; an F4 lens; a resolution sufficient to be able to detect and separate a 0.005 inch flat-bottomed hole at 0.005 inches below surface; and a beam size of approximately 0.006–0.008 inches measured off a 11/2 mm ball in water at the transducer's focal point.

  2. Ultrasound guided spine needle insertion

    NASA Astrophysics Data System (ADS)

    Chen, Elvis C. S.; Mousavi, Parvin; Gill, Sean; Fichtinger, Gabor; Abolmaesumi, Purang

    2010-02-01

    An ultrasound (US) guided, CT augmented, spine needle insertion navigational system is introduced. The system consists of an electromagnetic (EM) sensor, an US machine, and a preoperative CT volume of the patient anatomy. Three-dimensional (3D) US volume is reconstructed intraoperatively from a set of two-dimensional (2D) freehand US slices, and is coregistered with the preoperative CT. This allows the preoperative CT volume to be used in the intraoperative clinical coordinate. The spatial relationship between the patient anatomy, surgical tools, and the US transducer are tracked using the EM sensor, and are displayed with respect to the CT volume. The pose of the US transducer is used to interpolate the CT volume, providing the physician with a 2D "x-ray vision" to guide the needle insertion. Many of the system software components are GPU-accelerated, allowing real-time performance of the guidance system in a clinical setting.

  3. PRESSURE TRANSDUCER

    DOEpatents

    Sander, H.H.

    1959-10-01

    A pressure or mechanical force transducer particularly adaptable to miniature telemetering systems is described. Basically the device consists of a transistor located within a magnetic field adapted to change in response to mechanical force. The conduction characteristics of the transistor in turn vary proportionally with changes in the magnetic flux across the transistor such that the output (either frequency of amplitude) of the transistor circuit is proportional to mechanical force or pressure.

  4. Pressure transducer

    DOEpatents

    Anderson, Thomas T.; Roop, Conard J.; Schmidt, Kenneth J.; Gunchin, Elmer R.

    1989-01-01

    A pressure transducer suitable for use in high temperature environments includes two pairs of induction coils, each pair being bifilarly wound together, and each pair of coils connected as opposite arms of a four arm circuit; an electrically conductive target moveably positioned between the coil pairs and connected to a diaphragm such that deflection of the diaphragm causes axial movement of the target and an unbalance in the bridge output.

  5. Pressure transducer

    DOEpatents

    Anderson, T.T.; Roop, C.J.; Schmidt, K.J.; Gunchin, E.R.

    1987-02-13

    A pressure transducer suitable for use in high temperature environments includes two pairs of induction coils, each pair being bifilarly wound together, and each pair of coils connected as opposite arms of a four arm circuit; an electrically conductive target moveably positioned between the coil pairs and connected to a diaphragm such that deflection of the diaphragm causes axial movement of the target and an unbalance in the bridge output. 7 figs.

  6. Ferrofluid Transducer.

    DTIC Science & Technology

    The patent discloses magnetic fluid transducer for producing a low-frequency sound field in a fluid medium. The device comprises a non-magnetic...cylindrical housing with end windows. The housing is surrounded by a magnetic-field-generator means and contains a magnetic fluid within the housing. The...magnetic field penetrates the housing and interacts with the magnetic fluid . A body force is developed within the fluid which produces an internal

  7. Multifunctional transducer

    NASA Technical Reports Server (NTRS)

    Feldstein, C.; Lewis, G. W.; Culler, V. H.; Merrbaum, S. (Inventor)

    1981-01-01

    Several parameters of a small region of a muscle tissue or other object, can be simultaneously measured using with minimal traumatizing or damage of the object, a trifunctional transducer which can determine the force applied by a muscle fiber, the displacement of the fiber, and the change in thickness of the fiber. The transducer has three legs with inner ends joined together and outer ends formed to piece the tissue and remain within it. Two of the legs are relatively stiff, to measure force applied by the tissue, and a third leg is relatively flexible to measure displacement of the tissue relative to one or both stiff legs, and with the three legs lying in a common plane so that the force and displacement measurements all relate to the same direction of muscle movements. A flexible loop is attached to one of the stiff legs to measure changes in muscle thickness, with the upper end of the loop fixed to the leg and the lower end of the loop bearing against the surface of the tissue and being free to slide on the leg.

  8. Acoustic impedance matching of piezoelectric transducers to the air.

    PubMed

    Gómez Alvarez-Arenas, Tomás E

    2004-05-01

    The purpose of this work is threefold: to investigate material requirements to produce impedance matching layers for air-coupled piezoelectric transducers, to identify materials that meet these requirements, and to propose the best solution to produce air-coupled piezoelectric transducers for the low megahertz frequency range. Toward this end, design criteria for the matching layers and possible configurations are reviewed. Among the several factors that affect the efficiency of the matching layer, the importance of attenuation is pointed out. A standard characterization procedure is applied to a wide collection of candidate materials to produce matching layers. In particular, some types of filtration membranes are studied. From these results, the best materials are identified, and the better matching configuration is proposed. Four pairs of air-coupled piezoelectric transducers also are produced to illustrate the performance of the proposed solution. The lowest two-way insertion loss figure is -24 dB obtained at 0.45 MHz. This increases for higher frequency transducers up to -42 dB at 1.8 MHz and -50 at 2.25 MHz. Typical bandwidth is about 15-20%.

  9. Effects of vibration excitation methodology and configuration of an acoustic needle on its tip vibration.

    PubMed

    Li, Ning; Hu, Junhui

    2013-04-01

    One of design purposes of an acoustic needle is to obtain a big vibration displacement at its tip. In this paper, vibration characteristics of the tip of the acoustic needle driven by a sandwich type ultrasonic transducer, is investigated to obtain the guidelines for increasing the tip vibration. It is found that the tip vibration can be increased by employing acoustic needles with proper vibration excitation structure and configuration. The effective measures include using a sandwich type piezoelectric transducer with flexurally vibrating end plates and an acoustic needle with conical tip section, decreasing the length of vibration excitation section at the needle root, bonding the needle root at a proper location of the transducer end plate, and tuning the length ratio of the conical tip section to the whole needle.

  10. Steerable real-time sonographically guided needle biopsy.

    PubMed

    Buonocore, E; Skipper, G J

    1981-02-01

    A method for dynamic real-time ultrasonic guidance for percutaneous needle biopsy has been successful in obtaining cytologic and histologic specimens from abdominal masses. The system depends on a real-time ultrasonic transducer that has been rigidly attached to a laterally placed steerable needle holder. Using simple trigonometric functions, a chart has been derived that gives the exact angulation and needle length to produce quick, reliable, guided needle placements. Examples of successful renal, hepatobiliary, and retroperitoneal biopsies are presented. Advantages of this technique include speed, accuracy, low cost, three-dimensional format, and the omission of contrast media and radiation.

  11. Measurement of the total acoustic output power of HITU transducers

    NASA Astrophysics Data System (ADS)

    Jenderka, Klaus-V.; Beissner, Klaus

    2010-03-01

    The majority of High Intensity Therapeutic Ultrasound (HITU) applications use strongly focused ultrasound fields generating very high local intensities in the focal region. The metrology of these high-power ultrasound fields is a challenge for the established measurement procedures and devices. This paper describes the results of measurements by means of the radiation force for a total acoustic output power up to 400 W at 1.5 MHz and up to 200 W at 2.45 MHz. For this purpose, a radiation force balance set-up was adapted for the determination of large acoustic output powers. For two types of HITU transducers, the relationship between the total acoustic output power and the applied net electrical power was determined at close transducer-target distance. Further, dependence of the measured electro-acoustic radiation conductance on the transducer-target distance was investigated at reduced power levels, considering the appearance of focal anomalies. Concluding, a list of the main uncertainty contributions, and an estimate of the uncertainty for the used radiation force balance set-up is given for measurements at high power levels.

  12. A flexible piezoelectric transducer design for efficient generation and reception of ultrasonic Lamb waves.

    PubMed

    Gachagan, Anthony; Hayward, Gordon; Banks, Robert

    2005-07-01

    This paper describes the development of a flexible piezoelectric transducer for the generation and detection of ultrasonic symmetrical Lamb waves in plate-like structures. This piezoplatelet transducer structure comprises an array of miniature piezoceramic plates embedded within a soft setting polymer filler material, combining the efficiency of the active piezoceramic phase with a degree of flexibility, which is a function of the platelet/polymer dimensions. For many condition-monitoring applications, the generation of ultrasonic Lamb waves is often appropriate, and this was achieved by incorporating interdigital design techniques via the transducer electrode pattern. The performance of the piezoplatelet transducer structure was evaluated using a combination of linear systems and finite-element modeling, substantiated by experimental results. Importantly, the transducer is shown to operate as an ensemble of platelets, each operating in the thickness mode and well decoupled from neighboring piezoelectric elements. Using this transducer configuration, an unimodal s1 Lamb wave, at 1.45 MHz, has been generated and detected in a 3-mm thick steel plate. Furthermore, a propagation distance of almost 1 m was recorded for s0 Lamb wave generation/detection in a fiber-reinforced composite plate.

  13. Modeling, Production, and Testing of an Echogenic Needle for Ultrasound-Guided Nerve Blocks.

    PubMed

    Bigeleisen, Paul E; Hess, Aaron; Zhu, Richard; Krediet, Annelot

    2016-06-01

    We have designed, produced, and tested an echogenic needle based on a sawtooth pattern where the height of the tooth was 1.25 times the wavelength of the ultrasound transducer. A numeric solution to the time-independent wave equation (Helmholtz equation) was used to create a model of backscattering from a needle. A 21-gauge stainless steel prototype was manufactured and tested in a water bath. Backscattering from the needle was compared to theoretical predications from our model. Based on these results, an 18-gauge prototype needle was fabricated from stainless steel and tested in a pig cadaver. This needle was compared to a commercial 18-gauge echogenic needle (Pajunk Medical Systems, Tucker, GA) by measuring the brightness of the needle relative to the background of sonograms of a needle in a pig cadaver. The backscattering from the 21-gauge prototype needle reproduced the qualitative predictions of our model. At 30° and 45° of insonation, our prototype performed equivalently to the Pajunk needle. At 60°, our prototype was significantly brighter than the Pajunk needle (P = .017). In conclusion, we chose a model for the design of an echogenic needle and modeled it on the basis of a solution to the Helmholtz equation. A prototype needle was tested in a water bath and compared to the model prediction. After verification of our model, we designed an 18-gauge needle, which performed better than an existing echogenic needle (Pajunk) at 60° of insonation. Our needle will require further testing in human trials.

  14. Emergency physician's needle holder.

    PubMed

    Abidin, M R; Towler, M A; Lombardi, S A; Becker, D G; Thacker, J G; McGregor, W; Edlich, R F

    1989-01-01

    A new needle holder is described that has jaws metallurgically bonded with tungsten carbide particles that enhance needle holding security without causing sutural damage during instrument ties. Scissors have also been incorporated into the needle holder to cut sutures. One ringlet on a handle has been offset to facilitate retrieval of the needle holder from a flat surface.

  15. Transducer characterization for Vibrothermography

    NASA Astrophysics Data System (ADS)

    Vaddi, Jyani Somayajulu

    Vibrothermography, also known as Sonic IR and Thermosonics, is an NDE technique for finding cracks and flaws based on vibration-induced frictional rubbing of unbonded surfaces. The vibration is usually generated by a piezoelectric stack transducer which transduces electrical energy into large amplitude mechanical vibrations. The purpose of this study is to develop an understanding of the excitation process for vibrothermography so that optimal parameters and transducers for the testing can be selected. The amplitude and impedance transfer characteristics of the transducer system control the vibration of the sample. Within a linear contact (no tip chatter) model, the interaction between the transducer system and the specimen can be characterized using the theory of linear time-invariant (LTI) systems and electro-mechanical Norton equivalence. This work presents quantitative measurements of the performance of piezoelectric stack transducers in a vibrothermography excitation system and the effect of transducer performance and specimen characteristics on the induced vibration in the specimen. We show that with compliant coupling, the specimen vibration is directly proportional to the transducer open circuit velocity and that the system resonances generated because of metal-metal contact of specimen and transducer are disconnected by adding a couplant between specimen and transducer. We then give suggestions for transducer and couplant selection for vibrothermography and suggest methods to flatten the velocity spectrum of the transducer. We extend our analysis to high amplitude transducer behavior and elaborate on the effect of power amplifier saturation on the transducer behavior. The saturation effect negates the effect of adding an external inductance to flatten the transducer velocity spectrum. Finally, preliminary results are reported on the effect of transducer degradation phenomenon.

  16. PRESSURE TRANSDUCER RESEARCH.

    DTIC Science & Technology

    PIEZOELECTRIC TRANSDUCERS, PRESSURE), UNDERGROUND EXPLOSIONS, ELECTRICAL RESISTANCE, SEEBECK EFFECT , PRESSURE GAGES, SHOCK WAVES, STRESSES, COMPUTER PROGRAMMING, NUCLEAR EXPLOSIONS, NUCLEAR RADIATION.

  17. Transducer applications, a compilation

    NASA Technical Reports Server (NTRS)

    1972-01-01

    The characteristics and applications of transducers are discussed. Subjects presented are: (1) thermal measurements, (2) liquid level and fluid flow measurements, (3) pressure transducers, (4) stress-strain measurements, (5) acceleration and velocity measurements, (6) displacement and angular rotation, and (7) transducer test and calibration methods.

  18. Megahertz tonpilz transducer

    NASA Astrophysics Data System (ADS)

    Van Tol, Dave; Hughes, W. Jack

    1999-06-01

    The tonpilz configuration is applied to a transducer operating in the megahertz frequency range. The KLM model is used to design the transducer using readily available components. The construction techniques used are the same as those applied to standard high frequency transducers. Modeled and measured pulse-echo results display a high level of agreement, but impedance and sensitivity comparisons are less promising.

  19. Integrated transducer systems

    NASA Astrophysics Data System (ADS)

    Syrzycki, Marek; Parameswaran, M.; Chapman, Glenn H.

    1995-06-01

    In the paper we discuss possible solutions to problems pertaining the implementation of integrated transducer systems, based on examples of WSI image transducers, magnetic field sensors and tactile sensors arrays, as well as arrays of chemical sensors. We also present the issues common to large area transducer arrays, such as building-in redundancy into WSI transducer arrays, and frequency domain circuits for the future communication pathway in integrated transducer systems. Advantages of standard CMOS technology, enhanced with various post-fabrication processes such as silicon micromachining and laser linking, are also stressed.

  20. Trielectrode capacitive pressure transducer

    NASA Technical Reports Server (NTRS)

    Coon, G. W. (Inventor)

    1976-01-01

    A capacitive transducer and circuit especially suited for making measurements in a high-temperature environment are described. The transducer includes two capacitive electrodes and a shield electrode. As the temperature of the transducer rises, the resistance of the insulation between the capacitive electrode decreases and a resistive current attempts to interfere with the capacitive current between the capacitive electrodes. The shield electrode and the circuit coupled there reduce the resistive current in the transducer. A bridge-type circuit coupled to the transducer ignores the resistive current and measures only the capacitive current flowing between the capacitive electrodes.

  1. Crossflow force transducer. [LMFBR

    SciTech Connect

    Mulcahy, T M

    1982-05-01

    A force transducer for measuring lift and drag coefficients for a circular cylinder in turbulent water flow is presented. In addition to describing the actual design and construction of the strain-gauged force- ring based transducer, requirements for obtained valid fluid force test data are discussed, and pertinent flow test experience is related.

  2. Experiments with Ultrasonic Transducers.

    ERIC Educational Resources Information Center

    Greenslade, Thomas R., Jr.

    1994-01-01

    Discusses the use of 40 kHz ultrasonic transducers to study wave phenomena. Determines that the resulting wavelength of 9 mm allows acoustic experiments to be performed on a tabletop. Includes transducer characteristics and activities on speed of sound, reflection, double- and single-slit diffraction, standing waves, acoustical zone plate, and…

  3. Triple-resonant transducers.

    PubMed

    Butler, Stephen C

    2012-06-01

    A detailed analysis is presented of two novel multiple-resonant transducers which produce a wider transmit response than that of a conventional Tonpilz-type transducer. These multi-resonant transducers are Tonpilz-type longitudinal vibrators that produce three coupled resonances and are referred to as triple-resonant transducers (TRTs). One of these designs is a mechanical series arrangement of a tail mass, piezoelectric ceramic stack, central mass, compliant spring, second central mass, second compliant spring, and a piston-radiating head mass. The other TRT design is a mechanical series arrangement of a tail mass, piezoelectric ceramic stack, central mass, compliant spring, and head mass with a quarter-wave matching layer of poly(methyl methacrylate) on the head mass. Several prototype transducer element designs were fabricated that demonstrated proof-of-concept.

  4. Compact Transducers and Arrays

    DTIC Science & Technology

    2005-05-01

    Soc. Am., 104, pp.64-71 44 25.Decarpigny, J.N., J.C. Debus, B. Tocquet & D. Boucher. 1985. "In-Air Analysis Of Piezoelectric Tonpilz Transducers In A... Transducers and Arrays Final Report May 2005 Contacts: Dr. Robert E. Newnham The Pennsylvania State University, 251 MRL, University Park, PA 16802 phone...814) 865-1612 fax: (814) 865-2326 email: ....c xx.....i.i.....ht.. .u a.p.u..c.e.du. Dr. Richard J. Meyer, Jr. Systems Engineering ( Transducers ), ARL

  5. Digital magnetic temperature transducer.

    NASA Technical Reports Server (NTRS)

    Tchernev, D. I.; Collier, T. E.

    1971-01-01

    A new digital magnetic temperature transducer is reported. The device utilizes the discontinuous behavior of the initial permeability with temperature at the Curie temperature of some magnetic materials. Since the Curie temperature is determined by the chemical and crystallographic composition of the particular material only, the transducer requires no calibration and has extremely high stability and reproducibility with time. The output of the transducer is inherently digital and, therefore, is directly compatible with the digital information processing and control without A/D conversion. The temperature-sensing portion of the transducer consists only of magnetic cores and wire and, therefore, has extremely high reliability, is shock and radiation insensitive, small, and virtually indestructible.

  6. Improved myocardium transducer

    NASA Technical Reports Server (NTRS)

    Culler, V. H.; Feldstein, C.; Lewis, G. W.

    1979-01-01

    Method of implanting myocardium transducer uses special indented pins that are caught and securely held by epicardial fibers. Pins are small enough to cause minimum of trauma to myocardium during implantation or removal.

  7. Multilayer ionic polymer transducer

    NASA Astrophysics Data System (ADS)

    Akle, Barbar J.; Leo, Donald J.

    2003-07-01

    A transducer consisting of multiple layers of ionic polymer material is developed for applications in sensing, actuation, and control. The transducer consists of two to four individual layers each approximately 200 microns thick. The transducers are connected in parallel to minimize the electric field requirements for actuation. The tradeoff in deflection and force can be controlled by controlling the mechanical constraint at the interface. Packaging the transducer in an outer coating produces a hard constraint between layers and reduces the deflection with a force that increases linearly with the number of layers. This configuration also increases the bandwidth of the transducer. Removing the outer packaging produces an actuator that maintains the deflection of a single layer but has an increased force output. This is obtained by allowing the layers to slide relative to one another during bending. Experiments on transducers with one to three layers are performed and the results are compared to Newbury"s equivalent circuit model, which was modified to accommodate the multilayer polymers. The modification was performed on four different boundary conditions, two electrical the series and the parallel connection, and two mechanical the zero interfacial friction and the zero slip on the interface. Results demonstrate that the largest obstacle to obtaining good performance is water transport between the individual layers. Water crossover produces a near short circuit electrical condition and produces feedthrough between actuation layers and sensing layers. Electrical feedthrough due to water crossover eliminates the ability to produce a transducer that has combined sensing and actuation properties. Eliminating water crossover through good insulation enables the development of a small (5 mm x 30 mm) transducer that has sensing and actuation bandwidth on the order of 100 Hz.

  8. Precessing Ferromagnetic Needle Magnetometer.

    PubMed

    Jackson Kimball, Derek F; Sushkov, Alexander O; Budker, Dmitry

    2016-05-13

    A ferromagnetic needle is predicted to precess about the magnetic field axis at a Larmor frequency Ω under conditions where its intrinsic spin dominates over its rotational angular momentum, Nℏ≫IΩ (I is the moment of inertia of the needle about the precession axis and N is the number of polarized spins in the needle). In this regime the needle behaves as a gyroscope with spin Nℏ maintained along the easy axis of the needle by the crystalline and shape anisotropy. A precessing ferromagnetic needle is a correlated system of N spins which can be used to measure magnetic fields for long times. In principle, by taking advantage of rapid averaging of quantum uncertainty, the sensitivity of a precessing needle magnetometer can far surpass that of magnetometers based on spin precession of atoms in the gas phase. Under conditions where noise from coupling to the environment is subdominant, the scaling with measurement time t of the quantum- and detection-limited magnetometric sensitivity is t^{-3/2}. The phenomenon of ferromagnetic needle precession may be of particular interest for precision measurements testing fundamental physics.

  9. Mass-spring matching layers for high-frequency ultrasound transducers: a new technique using vacuum deposition.

    PubMed

    Brown, Jeremy; Sharma, Srikanta; Leadbetter, Jeff; Cochran, Sandy; Adamson, Rob

    2014-11-01

    We have developed a technique of applying multiple matching layers to high-frequency (>30 MHz) imaging transducers, by using carefully controlled vacuum deposition alone. This technique uses a thin mass-spring matching layer approach that was previously described in a low-frequency (1 to 10 MHz) transducer design with epoxied layers. This mass- spring approach is more suitable to vacuum deposition in highfrequency transducers over the conventional quarter-wavelength resonant cavity approach, because thinner layers and more versatile material selection can be used, the difficulty in precisely lapping quarter-wavelength matching layers is avoided, the layers are less attenuating, and the layers can be applied to a curved surface. Two different 3-mm-diameter 45-MHz planar lithium niobate transducers and one geometrically curved 3-mm lithium niobate transducer were designed and fabricated using this matching layer approach with copper as the mass layer and parylene as the spring layer. The first planar lithium niobate transducer used a single mass-spring matching network, and the second planar lithium niobate transducer used a single mass-spring network to approximate the first layer in a dual quarter-wavelength matching layer system in addition to a conventional quarter-wavelength layer as the second matching layer. The curved lithium niobate transducer was press focused and used a similar mass-spring plus quarter-wavelength matching layer network. These transducers were then compared with identical transducers with no matching layers and the performance improvement was quantified. The bandwidth of the lithium niobate transducer with the single mass-spring layer was measured to be 46% and the insertion loss was measured to be -21.9 dB. The bandwidth and insertion loss of the lithium niobate transducer with the mass-spring network plus quarter-wavelength matching were measured to be 59% and -18.2 dB, respectively. These values were compared with the unmatched

  10. Needle breakage: incidence and prevention.

    PubMed

    Malamed, Stanley F; Reed, Kenneth; Poorsattar, Susan

    2010-10-01

    Since the introduction of nonreusable, stainless steel dental local anesthetic needles, needle breakage has become an extremely rare complication of dental local anesthetic injections. But although rare, dental needle breakage can, and does, occur. Review of the literature and personal experience brings into focus several commonalities which, when avoided, can minimize the risk of needle breakage with the fragment being retained from occurring.

  11. Glass-windowed ultrasound transducers.

    PubMed

    Yddal, Tostein; Gilja, Odd Helge; Cochran, Sandy; Postema, Michiel; Kotopoulis, Spiros

    2016-05-01

    In research and industrial processes, it is increasingly common practice to combine multiple measurement modalities. Nevertheless, experimental tools that allow the co-linear combination of optical and ultrasonic transmission have rarely been reported. The aim of this study was to develop and characterise a water-matched ultrasound transducer architecture using standard components, with a central optical window larger than 10 mm in diameter allowing for optical transmission. The window can be used to place illumination or imaging apparatus such as light guides, miniature cameras, or microscope objectives, simplifying experimental setups. Four design variations of a basic architecture were fabricated and characterised with the objective to assess whether the variations influence the acoustic output. The basic architecture consisted of a piezoelectric ring and a glass disc, with an aluminium casing. The designs differed in piezoelectric element dimensions: inner diameter, ID=10 mm, outer diameter, OD=25 mm, thickness, TH=4 mm or ID=20 mm, OD=40 mm, TH=5 mm; glass disc dimensions OD=20-50 mm, TH=2-4 mm; and details of assembly. The transducers' frequency responses were characterised using electrical impedance spectroscopy and pulse-echo measurements, the acoustic propagation pattern using acoustic pressure field scans, the acoustic power output using radiation force balance measurements, and the acoustic pressure using a needle hydrophone. Depending on the design and piezoelectric element dimensions, the resonance frequency was in the range 350-630 kHz, the -6 dB bandwidth was in the range 87-97%, acoustic output power exceeded 1 W, and acoustic pressure exceeded 1 MPa peak-to-peak. 3D stress simulations were performed to predict the isostatic pressure required to induce material failure and 4D acoustic simulations. The pressure simulations indicated that specific design variations could sustain isostatic pressures up to 4.8 MPa.The acoustic simulations were able to

  12. Buffon's needle problem

    NASA Astrophysics Data System (ADS)

    Schröer, H.

    We accidentally let a needle fall with the length L on a table. On the table are drawn parallel lines with distance D. We assume L is smaller than D. We introduce the rotation probability. Then we generalize the Buffon's needle problem. We view a general convex set. We have to solve a two-dimensional integral. There is an english and a german edition.

  13. Catheter transducer and circuit

    NASA Technical Reports Server (NTRS)

    Harrison, D. R.; Kerwin, W. J.

    1971-01-01

    Simple integrated circuit located at transducer, enables use of single coaxial cable for both input and output connections. Circuit is sensitive to changes in RC time constant, has much improved sensitivity characteristics, and is unaffected by changes in cable capacitance effects.

  14. Broadband Ultrasonic Transducers

    NASA Technical Reports Server (NTRS)

    Heyser, R. C.

    1986-01-01

    New geometry spreads out resonance region of piezoelectric crystal. In new transducer, crystal surfaces made nonparallel. One surface planar; other, concave. Geometry designed to produce nearly uniform response over a predetermined band of frequencies and to attenuate strongly frequencies outside band. Greater bandwidth improves accuracy of sonar and ultrasonic imaging equipment.

  15. Modeling of phased array transducers.

    PubMed

    Ahmad, Rais; Kundu, Tribikram; Placko, Dominique

    2005-04-01

    Phased array transducers are multi-element transducers, where different elements are activated with different time delays. The advantage of these transducers is that no mechanical movement of the transducer is needed to scan an object. Focusing and beam steering is obtained simply by adjusting the time delay. In this paper the DPSM (distributed point source method) is used to model the ultrasonic field generated by a phased array transducer and to study the interaction effect when two phased array transducers are placed in a homogeneous fluid. Earlier investigations modeled the acoustic field for conventional transducers where all transducer points are excited simultaneously. In this research, combining the concepts of delayed firing and the DPSM, the phased array transducers are modeled semi-analytically. In addition to the single transducer modeling the ultrasonic fields from two phased array transducers placed face to face in a fluid medium is also modeled to study the interaction effect. The importance of considering the interaction effect in multiple transducer modeling is discussed, pointing out that neighboring transducers not only act as ultrasonic wave generators but also as scatterers.

  16. Curved PVDF airborne transducer.

    PubMed

    Wang, H; Toda, M

    1999-01-01

    In the application of airborne ultrasonic ranging measurement, a partially cylindrical (curved) PVDF transducer can effectively couple ultrasound into the air and generate strong sound pressure. Because of its geometrical features, the ultrasound beam angles of a curved PVDF transducer can be unsymmetrical (i.e., broad horizontally and narrow vertically). This feature is desired in some applications. In this work, a curved PVDF air transducer is investigated both theoretically and experimentally. Two resonances were observed in this transducer. They are length extensional mode and flexural bending mode. Surface vibration profiles of these two modes were measured by a laser vibrometer. It was found from the experiment that the surface vibration was not uniform along the curvature direction for both vibration modes. Theoretical calculations based on a model developed in this work confirmed the experimental results. Two displacement peaks were found in the piezoelectric active direction of PVDF film for the length extensional mode; three peaks were found for the flexural bending mode. The observed peak positions were in good agreement with the calculation results. Transient surface displacement measurements revealed that vibration peaks were in phase for the length extensional mode and out of phase for the flexural bending mode. Therefore, the length extensional mode can generate a stronger ultrasound wave than the flexural bending mode. The resonance frequencies and vibration amplitudes of the two modes strongly depend on the structure parameters as well as the material properties. For the transducer design, the theoretical model developed in this work can be used to optimize the ultrasound performance.

  17. Future needs for biomedical transducers

    NASA Technical Reports Server (NTRS)

    Wooten, F. T.

    1971-01-01

    In summary there are three major classes of transducer improvements required: improvements in existing transducers, needs for unexploited physical science phenomena in transducer design, and needs for unutilized physiological phenomena in transducer design. During the next decade, increasing emphasis will be placed on noninvasive measurement in all of these areas. Patient safety, patient comfort, and the need for efficient utilization of the time of both patient and physician requires that noninvasive methods of monitoring be developed.

  18. Ionic electroactive hybrid transducers

    NASA Astrophysics Data System (ADS)

    Akle, Barbar J.; Bennett, Matthew D.; Leo, Donald J.

    2005-05-01

    Ionic electroactive actuators have received considerable attention in the past ten years. Ionic electroactive polymers, sometimes referred to as artificial muscles, have the ability to generate large bending strain and moderate stress at low applied voltages. Typical types of ionic electroactive polymer transducers include ionic polymers, conducting polymers, and carbon nanotubes. Preliminary research combining multiple types of materials proved to enhance certain transduction properties such as speed of response, maximum strain, or quasi-static actuation. Recently it was demonstrated that ionomer-ionic liquid transducers can operate in air for long periods of time (>250,000 cycles) and showed potential to reduce or eliminate the back-relaxation issue associated with ionomeric polymers. In addition, ionic liquids have higher electrical stability window than those operated with water as the solvent thereby increasing the maximum strain that the actuator can produce. In this work, a new technique developed for plating metal particulates on the surface of ionomeric materials is applied to the development of hybrid transducers that incorporate carbon nanotubes and conducting polymers as electrode materials. The new plating technique, named the direct assembly process, consists of mixing a conducting powder with an ionomer solution. This technique has demonstrated improved response time and strain output as compared to previous methods. Furthermore, the direct assembly process is less costly to implement than traditional impregnation-reduction methods due to less dependence on reducing agents, it requires less time, and is easier to implement than other processes. Electrodes applied using this new technique of mixing RuO2 (surface area 45~65m2/g) particles and Nafion dispersion provided 5x the displacement and 10x the force compared to a transducer made with conventional methods. Furthermore, the study illustrated that the response speed of the transducer is optimized

  19. Nano-optomechanical transducer

    DOEpatents

    Rakich, Peter T; El-Kady, Ihab F; Olsson, Roy H; Su, Mehmet Fatih; Reinke, Charles; Camacho, Ryan; Wang, Zheng; Davids, Paul

    2013-12-03

    A nano-optomechanical transducer provides ultrabroadband coherent optomechanical transduction based on Mach-wave emission that uses enhanced photon-phonon coupling efficiencies by low impedance effective phononic medium, both electrostriction and radiation pressure to boost and tailor optomechanical forces, and highly dispersive electromagnetic modes that amplify both electrostriction and radiation pressure. The optomechanical transducer provides a large operating bandwidth and high efficiency while simultaneously having a small size and minimal power consumption, enabling a host of transformative phonon and signal processing capabilities. These capabilities include optomechanical transduction via pulsed phonon emission and up-conversion, broadband stimulated phonon emission and amplification, picosecond pulsed phonon lasers, broadband phononic modulators, and ultrahigh bandwidth true time delay and signal processing technologies.

  20. Three dimensional transducer

    DOEpatents

    Warren, Oden Lee; Asif, Syed Amanulla Syed; Oh, Yunje; Feng, Yuxin; Cyrankowski, Edward; Major, Ryan

    2014-09-30

    A testing instrument for mechanical testing at nano or micron scale includes a transducer body, and a coupling shaft coupled with a probe tip. A transducer body houses a capacitor. The capacitor includes first and second counter electrodes and a center electrode assembly interposed therebetween. The center electrode assembly is movable with the coupling shaft relative to the first and second counter electrodes, for instance in one or more of dimensions including laterally and normally. The center electrode assembly includes a center plate coupled with the coupling shaft and one or more springs extending from the center plate. Upper and lower plates are coupled with the center plate and cover the center plate and the one or more springs. A shaft support assembly includes one or more support elements coupled along the coupling shaft. The shaft support assembly provides lateral support to the coupling shaft.

  1. Needle Federated Search Engine

    SciTech Connect

    2009-12-01

    The Idaho National Laboratory (INL) has combined a number of technologies, tools, and resources to accomplish a new means of federating search results. The resulting product is a search engine called Needle, an open-source-based tool that the INL uses internally for researching across a wide variety of information repositories. Needle has a flexible search interface that allows end users to point at any available data source. A user can select multiple sources such as commercial databases (Web of Science, Engineering Index), external resources (WorldCat, Google Scholar), and internal corporate resources (email, document management system, library collections) in a single interface with one search query. In the future, INL hopes to offer this open-source engine to the public. This session will outline the development processes for making Needle™s search interface and simplifying the federation of internal and external data sources.

  2. Trigger Point Dry Needling.

    PubMed

    2017-03-01

    Increasingly, physical therapists in the United States and throughout the world are using dry needling to treat musculoskeletal pain, even though this treatment has been a controversial addition to practice. To better generalize to physical therapy practice the findings about dry needling thus far, the authors of a study published in the March 2017 issue of JOSPT identified the need for a systematic review examining the effectiveness of dry needling performed by physical therapists on people with musculoskeletal pain. Their review offers a meta-analysis of data from several included studies and assesses the evidence for risks of bias. J Orthop Sports Phys Ther 2017;47(3):150. doi:10.2519/jospt.2017.0502.

  3. Fluid force transducer

    DOEpatents

    Jendrzejczyk, Joseph A.

    1982-01-01

    An electrical fluid force transducer for measuring the magnitude and direction of fluid forces caused by lateral fluid flow, includes a movable sleeve which is deflectable in response to the movement of fluid, and a rod fixed to the sleeve to translate forces applied to the sleeve to strain gauges attached to the rod, the strain gauges being connected in a bridge circuit arrangement enabling generation of a signal output indicative of the magnitude and direction of the force applied to the sleeve.

  4. Training Tree Transducers

    DTIC Science & Technology

    2004-01-01

    trees (similar to the role played by the finite- state acceptor FSA for strings). We describe the version (equivalent to TSG ( Schabes , 1990)) where...strictly contained in tree sets of tree adjoining gram- mars (Joshi and Schabes , 1997). 4 Extended-LHS Tree Transducers (xR) Section 1 informally described...changes without modifying the training procedure, as long as we stick to tree automata. 10 Related Work Tree substitution grammars or TSG ( Schabes , 1990

  5. Polymer film composite transducer

    DOEpatents

    Owen, Thomas E.

    2005-09-20

    A composite piezoelectric transducer, whose piezoeletric element is a "ribbon wound" film of piezolectric material. As the film is excited, it expands and contracts, which results in expansion and contraction of the diameter of the entire ribbon winding. This is accompanied by expansion and contraction of the thickness of the ribbon winding, such that the sound radiating plate may be placed on the side of the winding.

  6. Stress wave focusing transducers

    SciTech Connect

    Visuri, S.R., LLNL

    1998-05-15

    Conversion of laser radiation to mechanical energy is the fundamental process behind many medical laser procedures, particularly those involving tissue destruction and removal. Stress waves can be generated with laser radiation in several ways: creation of a plasma and subsequent launch of a shock wave, thermoelastic expansion of the target tissue, vapor bubble collapse, and ablation recoil. Thermoelastic generation of stress waves generally requires short laser pulse durations and high energy density. Thermoelastic stress waves can be formed when the laser pulse duration is shorter than the acoustic transit time of the material: {tau}{sub c} = d/c{sub s} where d = absorption depth or spot diameter, whichever is smaller, and c{sub s} = sound speed in the material. The stress wave due to thermoelastic expansion travels at the sound speed (approximately 1500 m/s in tissue) and leaves the site of irradiation well before subsequent thermal events can be initiated. These stress waves, often evolving into shock waves, can be used to disrupt tissue. Shock waves are used in ophthalmology to perform intraocular microsurgery and photodisruptive procedures as well as in lithotripsy to fragment stones. We have explored a variety of transducers that can efficiently convert optical to mechanical energy. One such class of transducers allows a shock wave to be focused within a material such that the stress magnitude can be greatly increased compared to conventional geometries. Some transducer tips could be made to operate regardless of the absorption properties of the ambient media. The size and nature of the devices enable easy delivery, potentially minimally-invasive procedures, and precise tissue- targeting while limiting thermal loading. The transducer tips may have applications in lithotripsy, ophthalmology, drug delivery, and cardiology.

  7. Evaluation of nonholonomic needle steering using a robotic needle driver

    NASA Astrophysics Data System (ADS)

    Wilson, Emmanuel; Ding, Jeinan; Carignan, Craig; Krishnan, Karthik; Avila, Rick; Turner, Wes; Stoianovici, Dan; Yankelevitz, David; Banovac, Filip; Cleary, Kevin

    2010-02-01

    Accurate needle placement is a common need in the medical environment. While the use of small diameter needles for clinical applications such as biopsy, anesthesia and cholangiography is preferred over the use of larger diameter needles, precision placement can often be challenging, particularly for needles with a bevel tip. This is due to deflection of the needle shaft caused by asymmetry of the needle tip. Factors such as the needle shaft material, bevel design, and properties of the tissue penetrated determine the nature and extent to which a needle bends. In recent years, several models have been developed to characterize the bending of the needle, which provides a method of determining the trajectory of the needle through tissue. This paper explores the use of a nonholonomic model to characterize needle bending while providing added capabilities of path planning, obstacle avoidance, and path correction for lung biopsy procedures. We used a ballistic gel media phantom and a robotic needle placement device to experimentally assess the accuracy of simulated needle paths based on the nonholonomic model. Two sets of experiments were conducted, one for a single bend profile of the needle and the second set of tests for double bending of the needle. The tests provided an average error between the simulated path and the actual path of 0.8 mm for the single bend profile and 0.9 mm for the double bend profile tests over a 110 mm long insertion distance. The maximum error was 7.4 mm and 6.9 mm for the single and double bend profile tests respectively. The nonholonomic model is therefore shown to provide a reasonable prediction of needle bending.

  8. Thin film strain transducer

    NASA Astrophysics Data System (ADS)

    Rand, J. L.

    1981-01-01

    Previous attempts to develop an appropriate sensor for measuring the stress or strain of high altitude balloons during flight are reviewed as well as the various conditions that must be met by such a device. The design, development and calibration of a transducer which promises to satisfy the necessary design constraints are described. The thin film strain transducer has a low effective modulus so as not to interfere with the strain that would naturally occur in the balloon. In addition, the transducer has a high sensitivity to longitudinal strain (7.216 mV/V/unit strain) which is constant for all temperature from room temperature to -80 C and all strains from 5 percent compression to 10 percent tensile strain. At the same time, the sensor is relatively insensitive (0.27 percent) to transverse forces. The device has a standard 350 ohm impedance which is compatible with available bridge balance, amplification and telemetry instrumentation now available for balloon flight. Recommendations are included for improved coatings to provide passive thermal control as well as model, tethered and full scale flight testing.

  9. Improved performance of the optically scanned transducer

    NASA Astrophysics Data System (ADS)

    Turner, C. W.; Bolorforosh, M. S.

    1992-11-01

    The rapid increase in the use of ultrasound in both clinical and industrial applications requires more advanced and reliable imaging systems for calibrating and characterizing high performance ultrasonic transducers. The optically scanned hydrophone (OSH) is an alternative imaging system capable of quasi-real time imaging of broadband acoustic fields. The main application of the OSH is in the imaging and characterization of acoustic fields such as those emitted from clinical and therapeutic transducers. In this paper, the recent development of the OSH and its application to real time imaging of broadband acoustic fields are reported. Using improved fabrication techniques the optical sampling efficiency of the OSH has been considerably improved. This is achieved by adopting new assembly techniques and incorporating a novel differential electrode configuration. The improved optical sampling efficiency has provided a more competitive, versatile, and faster imaging system. The performance of the modified OSH is compared against the other types of hydrophone such as the spot poled and the needle types.

  10. Benchmarking of state-of-the-art needle detection algorithms in 3D ultrasound data volumes

    NASA Astrophysics Data System (ADS)

    Pourtaherian, Arash; Zinger, Svitlana; de With, Peter H. N.; Korsten, Hendrikus H. M.; Mihajlovic, Nenad

    2015-03-01

    Ultrasound-guided needle interventions are widely practiced in medical diagnostics and therapy, i.e. for biopsy guidance, regional anesthesia or for brachytherapy. Needle guidance using 2D ultrasound can be very challenging due to the poor needle visibility and the limited field of view. Since 3D ultrasound transducers are becoming more widely used, needle guidance can be improved and simplified with appropriate computer-aided analyses. In this paper, we compare two state-of-the-art 3D needle detection techniques: a technique based on line filtering from literature and a system employing Gabor transformation. Both algorithms utilize supervised classification to pre-select candidate needle voxels in the volume and then fit a model of the needle on the selected voxels. The major differences between the two approaches are in extracting the feature vectors for classification and selecting the criterion for fitting. We evaluate the performance of the two techniques using manually-annotated ground truth in several ex-vivo situations of different complexities, containing three different needle types with various insertion angles. This extensive evaluation provides better understanding on the limitations and advantages of each technique under different acquisition conditions, which is leading to the development of improved techniques for more reliable and accurate localization. Benchmarking results that the Gabor features are better capable of distinguishing the needle voxels in all datasets. Moreover, it is shown that the complete processing chain of the Gabor-based method outperforms the line filtering in accuracy and stability of the detection results.

  11. A "Needling" Complication.

    PubMed

    Banerji, John S; Govier, Fred E

    2016-11-01

    Intracavernosal injection therapy with vasoactive agents for treatment of erectile dysfunction has been around for more than 3 decades since its advent in the early 1980s. Common complications include ecchymosis and hematoma at the site of injection, priapism, and fibrosis. We describe a rare but potentially dangerous complication of breakage of needle during administering of injections, and discuss its successful retrieval.

  12. NEEDLE TRADES, MATHEMATICS - I.

    ERIC Educational Resources Information Center

    COLICCHIO, ANTOINETTE J.

    THE NEEDLE TRADES INDUSTRY CONSISTS OF THREE TYPES OF ESTABLISHMENTS -- THE REGULAR MANUFACTURERS, THE APPAREL JOBBERS, AND THE CONTRACTORS. THE FUNCTIONS INCLUDED COVER A WIDE SCOPE FROM BUYING OF RAW MATERIAL TO SELLING OF THE FINISHED APPAREL. THE PURPOSE OF THIS STUDY GUIDE IS TO FURNISH BASIC KNOWLEDGE IN MATHEMATICS AND DEVELOP SKILL IN…

  13. Transducers for ultrasonic limb plethysmography

    NASA Technical Reports Server (NTRS)

    Nickell, W. T.; Wu, V. C.; Bhagat, P. K.

    1983-01-01

    The design, construction, and performance characteristics of ultasonic transducers suitable for limb plethysmography are presented. Both 3-mm-diameter flat-plate and 12-mm-diameter hemispheric ceramic transducers operating at 2 MHz were fitted in 1-mm thick epoxy-resin lens/acoustic-coupling structures and mounted in exercie-EKG electrode housings for placement on the calf using adhesive collars. The effects of transducer directional characteristics on performance under off-axis rotation and the electrical impedances of the transducers were measured: The flat transducer was found to be sensitive to rotation and have an impedance of 800 ohms; the hemispheric transducer, to be unaffected by rotation and have an impedance of 80 ohms. The use of hemispheric transducers as both transmitter and receiver, or of a flat transducer as transmitter and a hemispheric transducer as receiver, was found to produce adequate dimensional measurements, with minimum care in transducer placement, in short-term physiological experiments and long-term (up to 7-day) attachment tests.

  14. Thin film strain transducer

    NASA Technical Reports Server (NTRS)

    Rand, J. L. (Inventor)

    1984-01-01

    A strain transducer system and process for making the same is disclosed. A beryllium copper ring having four strain gages is electrically connected in Wheatstone bridge fashion to the output instrumentation. Tabs are bonded to a balloon or like surface with strain on the surface causing bending of a ring which provides an electrical signal through the gages proportional to the surface strain. A photographic pattern of a one half ring segment as placed on a sheet of beryllium copper for chem-mill etch formation is illustrated.

  15. Lithium tetraborate transducer cuts

    NASA Astrophysics Data System (ADS)

    Kosinski, John; Ballato, Arthur; Lukaszek, Theodore

    1990-03-01

    Lithium tetraborate is a tetragonal material of considerable promise for frequency control and signal processing applications. It exhibits piezoelectric coupling values that fall between those of lithium niobate and quartz, but possesses orientations for which the temperature coefficient of frequency and delay time is zero for bulk and surface acoustic waves. In this report, we discuss the properties of two doubly rotated bulk wave resonator orientations having both first- and second-order temperature coefficients equal to zero. These are suitable for shear and compressional wave transducers in applications where very low temperature sensitivity is required simultaneously with moderately strong piezocoupling coefficients.

  16. Lithium tetraborate transducers

    NASA Astrophysics Data System (ADS)

    Ballato, Arthur; Kosinski, John A.; Lukaszek, Ted J.

    1991-01-01

    Lithium tetraborate is a tetragonal material of considerable promise for frequency control and signal processing applications. It exhibits piezoelectric coupling values that fall between those of lithium niobate and quartz, but possesses orientations for which the temperature coefficient of frequency and delay time is zero for bulk and surface acoustic waves. The properties of two doubly rotated bulk wave resonator orientations having first- and second-order temperature coefficients equal to zero are discussed. These are suitable for shear and compressional wave transducers in applications where very low temperature sensitivity is required simultaneously with moderately strong piezocoupling coefficients.

  17. An electromechanical displacement transducer

    NASA Astrophysics Data System (ADS)

    Villiers, Marius; Mahboob, Imran; Nishiguchi, Katsuhiko; Hatanaka, Daiki; Fujiwara, Akira; Yamaguchi, Hiroshi

    2016-08-01

    Two modes of an electromechanical resonator are coupled through the strain inside the structure with a cooperativity as high as 107, a state-of-the-art value for purely mechanical systems, which enables the observation of normal-mode splitting. This coupling is exploited to transduce the resonator’s fundamental mode into the bandwidth of the second flexural mode, which is 1.4 MHz higher in frequency. Thus, an all-mechanical heterodyne detection scheme is implemented that can be developed into a high-precision displacement sensor.

  18. Wellbore pressure transducer

    DOEpatents

    Shuck, Lowell Z.

    1979-01-01

    Subterranean earth formations containing energy values are subjected to hydraulic fracturing procedures to enhance the recovery of the energy values. These fractures are induced in the earth formation by pumping liquid into the wellbore penetrating the earth formation until the pressure of the liquid is sufficient to fracture the earth formation adjacent to the wellbore. The present invention is directed to a transducer which is positionable within the wellbore to generate a signal indicative of the fracture initiation useful for providing a timing signal to equipment for seismic mapping of the fracture as it occurs and for providing a measurement of the pressure at which the fracture is initiated.

  19. RADIO-ACTIVE TRANSDUCER

    DOEpatents

    Wanetick, S.

    1962-03-01

    ABS>ure the change in velocity of a moving object. The transducer includes a radioactive source having a collimated beam of radioactive particles, a shield which can block the passage of the radioactive beam, and a scintillation detector to measure the number of radioactive particles in the beam which are not blocked by the shield. The shield is operatively placed across the radioactive beam so that any motion normal to the beam will cause the shield to move in the opposite direction thereby allowing more radioactive particles to reach the detector. The number of particles detected indicates the acceleration. (AEC)

  20. Robot-Assisted Needle Steering

    PubMed Central

    Reed, Kyle B.; Majewicz, Ann; Kallem, Vinutha; Alterovitz, Ron; Goldberg, Ken; Cowan, Noah J.; Okamura, Allison M.

    2012-01-01

    Needle insertion is a critical aspect of many medical treatments, diagnostic methods, and scientific studies, and is considered to be one of the simplest and most minimally invasive medical procedures. Robot-assisted needle steering has the potential to improve the effectiveness of existing medical procedures and enable new ones by allowing increased accuracy through more dexterous control of the needle tip path and acquisition of targets not accessible by straight-line trajectories. In this article, we describe a robot-assisted needle steering system that uses three integrated controllers: a motion planner concerned with guiding the needle around obstacles to a target in a desired plane, a planar controller that maintains the needle in the desired plane, and a torsion compensator that controls the needle tip orientation about the axis of the needle shaft. Experimental results from steering an asymmetric-tip needle in artificial tissue demonstrate the effectiveness of the system and its sensitivity to various environmental and control parameters. In addition, we show an example of needle steering in ex vivo biological tissue to accomplish a clinically relevant task, and highlight challenges of practical needle steering implementation. PMID:23028210

  1. Transducer of linear displacements

    NASA Astrophysics Data System (ADS)

    Malamed, Y. R.

    1984-02-01

    The basic PLP transducer is designed for a UIM-29 microscope and a 2-coordinate measuring instrument with electronic digital readout. Its optical system consists of an AL-107B light-emitting diode as light source, two condenser lenses, a special wedge carrying two pairs of joined receiver lenses, a prism-mirror, a photoreceiver, a wedge-shape transparent replica of a twin diffraction grating which prevents light reflected by the air-glass interface from focusing on the receiver photodiodes, and a reflective replica of a diffraction grating on a movable carriage. The already available three models of this transducer are PLP1-0.2, PLP1-0.5, and PLP1-1.0 with respectively 625, 250, 125 lines/mm on the transparent replica and respectively 312.5, 125, 62.5 lines/mm on the reflective replica. The scale of moire-interference fringes characterizing the shift between both diffraction gratings per grating period (9.16 mm in each model) is respectively 0.8, 2.0, 4.0 microns and the angle between the two arrays of grating lines on the transparent replica is respectively 36 + or - 4 deg, 90 + or - 10 deg, 190 + or - 20 deg.

  2. Improved Piezoelectric Loudspeakers And Transducers

    NASA Technical Reports Server (NTRS)

    Regan, Curtis Randall; Jalink, Antony; Hellbaum, Richard F.; Rohrbach, Wayne W.

    1995-01-01

    Loudspeakers and related acoustic transducers of improved type feature both light weight and energy efficiency of piezoelectric transducers and mechanical coupling efficiency. Active component of transducer made from wafer of "rainbow" piezoelectric material, ceramic piezoelectric material chemically reduced on one face. Chemical treatment forms wafer into dishlike shallow section of sphere. Both faces then coated with electrically conductive surface layers serving as electrodes. Applications include high-fidelity loudspeakers, and underwater echo ranging devices.

  3. Ultrasonic Transducers for Fourier Analysis.

    ERIC Educational Resources Information Center

    Greenslade, Thomas B., Jr.

    1995-01-01

    Describes an experiment that uses the ultrasonic transducer for demonstrating the Fourier components of waveshapes such as the square and triangular waves produced by laboratory function generators. (JRH)

  4. [Transducer hygiene -- an underrated topic?].

    PubMed

    Merz, E

    2005-02-01

    Transducers are medical products that are categorized as uncritical, semicritical and critical, depending on their applications and perceived risks. Uncritical medical products are transducers that solely come in contact with the intact skin, such as transducers used for sonography of the abdomen or breast. Semicritical medical products are transducers that come in contact with mucosal membranes or diseased skin, comprising transducers used for transesophageal, transvesical, transvaginal, transrectal and perineal sonography. Critical medical products are transducers that come in contact with blood, internal tissues or organs, such as transducers used for intraoperative sonography. Under the most unfavorable circumstances, sonographic transducers can become contaminated with pathogenic agents (e. g., MRSA, HBV, HCV, HIV, Herpes viruses) and turn into a not to be underrated source of infection. For this reason, correct handling as well as cleaning and disinfection of the transducers are indispensable. Depending on the application, the recommended handling of the transducers differs. Transducers counted to the uncritical medical products are adequately cleaned by removal of the applied ultrasound gel with subsequent wipe disinfection (e. g., foam spray). Transducers counted to the semicritical medical products, such as transvaginal or perineal transducers , should be exclusively used after a suitable cover has been applied. A Latex(R) allergy must be excluded before the examination. The cover is to be disposed after completion of the examination and the transducer itself cleaned and disinfected. The disinfecting agent must be antiviral but also compatible with the material (caution: damage to the transducer membrane when using an unsuited alcoholic disinfecting agent). In case of rupture of the protecting cover during the examination, the transducer is considered contaminated with secretion or even blood and must be thoroughly cleaned with subsequent disinfection

  5. Biopsy needle tips with markers--MR compatible needles for high-precision needle tip positioning.

    PubMed

    Müller-Bierl, Bernd M; Martirosian, Petros; Graf, Hansjörg; Boss, Andreas; König, Claudius; Pereira, Philippe L; Schick, Fritz

    2008-06-01

    Needle tip visualization is of high importance in magnetic resonance imaging (MRI) guided interventional procedures, for example for taking biopsies from suspicious lesions in the liver or kidney. The exact position of the needle tip is often obscured by image artifacts arising from the magnetic properties of the needle. The authors investigated two special biopsy needle tip designs using diamagnetic coatings. For common interventional MR sequences, the needle tip can be identified in the MR image by several equidistant dark spots arranged along a straight line. A dotted instead of a solid line allows for an improved control of the movement of the needle, not only if the needle is tilted toward the imaging plane, but also if the needle leaves an empty canal with signal extinction, which cannot be distinguished from the needle material itself. With the proposed design the position of the needle tip can be estimated with a precision of approximately 1 mm using conventional FLASH, FISP, and TSE sequences, as used for interventional MR. Furthermore, the size of the biopsy probe can be estimated from the artifact. In using needles with a properly designed tip coating, taking biopsies under MR control is beginning to be greatly simplified. The approach to design artifacts using diamagnetic material in combination with paramagnetic material paves the way toward new instruments and implants, suitably tailored to the needs of the interventional radiologist.

  6. An opening electromagnetic transducer

    NASA Astrophysics Data System (ADS)

    Sun, Yanhua; Kang, Yihua

    2013-12-01

    Tubular solenoids have been widely used without any change since an electrical wire was discovered to create magnetic fields by Hans Christian Oersted in 1820 and thereby the wire was first coiled as a helix into a solenoid coil by William Sturgeon in 1823 and was improved by Joseph Henry in 1829 [see http://www.myetymology.com/encyclopedia/History_of_the_electricity.html; J. M. D. Coey, Magnetism and Magnetic Materials (Cambridge University Press, New York, 2010); and F. Winterberg, Plasma Phys. 8, 541553 (1996)]. A magnetic control method of C-shaped carrying-current wire is proposed, and thereby a new opening electromagnetic transducer evidently differing from the traditional tubular solenoid is created, capable of directly encircling and centering the acted objects in it, bringing about convenient and innovative electromagnetic energy conversion for electromagnetic heating, electromagnetic excitation, physical information capture, and electro-mechanical motion used in science research, industry, and even biomedical activities.

  7. Electromagnetic acoustic transducer

    DOEpatents

    Alers, George A.; Burns, Jr., Leigh R.; MacLauchlan, Daniel T.

    1988-01-01

    A noncontact ultrasonic transducer for studying the acoustic properties of a metal workpiece includes a generally planar magnetizing coil positioned above the surface of the workpiece, and a generally planar eddy current coil between the magnetizing coil and the workpiece. When a large current is passed through the magnetizing coil, a large magnetic field is applied to the near-surface regions of the workpiece. The eddy current coil can then be operated as a transmitter by passing an alternating current therethrough to excite ultrasonic waves in the surface of the workpiece, or operated as a passive receiver to sense ultrasonic waves in the surface by measuring the output signal. The geometries of the two coils can be varied widely to be effective for different types of ultrasonic waves. The coils are preferably packaged in a housing which does not interfere with their operation, but protects them from a variety of adverse environmental conditions.

  8. Optically transduced MEMS magnetometer

    DOEpatents

    Nielson, Gregory N; Langlois, Eric

    2014-03-18

    MEMS magnetometers with optically transduced resonator displacement are described herein. Improved sensitivity, crosstalk reduction, and extended dynamic range may be achieved with devices including a deflectable resonator suspended from the support, a first grating extending from the support and disposed over the resonator, a pair of drive electrodes to drive an alternating current through the resonator, and a second grating in the resonator overlapping the first grating to form a multi-layer grating having apertures that vary dimensionally in response to deflection occurring as the resonator mechanically resonates in a plane parallel to the first grating in the presence of a magnetic field as a function of the Lorentz force resulting from the alternating current. A plurality of such multi-layer gratings may be disposed across a length of the resonator to provide greater dynamic range and/or accommodate fabrication tolerances.

  9. Underwater Multimode Directional Transducer Evaluation

    DTIC Science & Technology

    2003-12-01

    The work described in the present thesis is intended to establish a procedure for analyzing directional transducers for future underwater wireless...networks, as well as to carry out the performance evaluation of a multimode transducer prototype with respect to its main operational requirements

  10. Needle bar for warp knitting machines

    DOEpatents

    Hagel, Adolf; Thumling, Manfred

    1979-01-01

    Needle bar for warp knitting machines with a number of needles individually set into slits of the bar and having shafts cranked to such an extent that the head section of each needle is in alignment with the shaft section accommodated by the slit. Slackening of the needles will thus not influence the needle spacing.

  11. Circuit for Driving Piezoelectric Transducers

    NASA Technical Reports Server (NTRS)

    Randall, David P.; Chapsky, Jacob

    2009-01-01

    The figure schematically depicts an oscillator circuit for driving a piezoelectric transducer to excite vibrations in a mechanical structure. The circuit was designed and built to satisfy application-specific requirements to drive a selected one of 16 such transducers at a regulated amplitude and frequency chosen to optimize the amount of work performed by the transducer and to compensate for both (1) temporal variations of the resonance frequency and damping time of each transducer and (2) initially unknown differences among the resonance frequencies and damping times of different transducers. In other words, the circuit is designed to adjust itself to optimize the performance of whichever transducer is selected at any given time. The basic design concept may be adaptable to other applications that involve the use of piezoelectric transducers in ultrasonic cleaners and other apparatuses in which high-frequency mechanical drives are utilized. This circuit includes three resistor-capacitor networks that, together with the selected piezoelectric transducer, constitute a band-pass filter having a peak response at a frequency of about 2 kHz, which is approximately the resonance frequency of the piezoelectric transducers. Gain for generating oscillations is provided by a power hybrid operational amplifier (U1). A junction field-effect transistor (Q1) in combination with a resistor (R4) is used as a voltage-variable resistor to control the magnitude of the oscillation. The voltage-variable resistor is part of a feedback control loop: Part of the output of the oscillator is rectified and filtered for use as a slow negative feedback to the gate of Q1 to keep the output amplitude constant. The response of this control loop is much slower than 2 kHz and, therefore, does not introduce significant distortion of the oscillator output, which is a fairly clean sine wave. The positive AC feedback needed to sustain oscillations is derived from sampling the current through the

  12. Fine needle aspiration cytology.

    PubMed Central

    Lever, J V; Trott, P A; Webb, A J

    1985-01-01

    Fine needle aspiration cytology is an inexpensive, atraumatic technique for the diagnosis of disease sites. This paper describes the technique and illustrates how it may be applied to the management of tumours throughout the body. The limitations of the method, the dangers of false positive reports, and the inevitability of false negative diagnoses are emphasised. In a clinical context the method has much to offer by saving patients from inappropriate operations and investigations and allowing surgeons to plan quickly and more rationally. It is an economically valuable technique and deserves greater recognition. Images PMID:2578481

  13. Needling the early universe

    NASA Technical Reports Server (NTRS)

    Hawkins, Isabel; Wright, Edward L.

    1988-01-01

    The possibility that the whole microwave background can be produced by a bright population of pregalactic stars at a redshift of a few hundred is explored. The radiation is thermalized by a combination of amorphous silicate, amorphous carbon, graphite, and needle-shaped conducting grains which give rise to the opacity needed at wavelengths greater than 3 cm. The occurrence of distortion in a primordial microwave background spectrum due to its interaction with Population III stars and dust is investigated. The possibility of producing deviations small enough to be consistent with the best available observations, but still detectable by COBE, is considered.

  14. Ban on needle swaps.

    PubMed

    1999-10-01

    A District of Columbia appropriations bill banning spending for needle-exchange programs will be going to President Clinton for signature. The House voted to approve the bill, and the Senate voted to accept it. Politicians from both parties are lobbying the President about the bill. Clinton's budget director, Jacob J. Lew, and D.C. Del. Eleanor Holmes Norton, argue against signing the bill. Rep. Thomas M. Davis warns a veto would scuttle legislation that funds education reforms and cleanup of the Anacostia River.

  15. Micromachined silicon seismic transducers

    SciTech Connect

    Barron, C.C.; Fleming, J.G.; Sniegowski, J.J.; Armour, D.L.; Fleming, R.P.

    1995-08-01

    Batch-fabricated silicon seismic transducers could revolutionize the discipline of CTBT monitoring by providing inexpensive, easily depolyable sensor arrays. Although our goal is to fabricate seismic sensors that provide the same performance level as the current state-of-the-art ``macro`` systems, if necessary one could deploy a larger number of these small sensors at closer proximity to the location being monitored in order to compensate for lower performance. We have chosen a modified pendulum design and are manufacturing prototypes in two different silicon micromachining fabrication technologies. The first set of prototypes, fabricated in our advanced surface- micromachining technology, are currently being packaged for testing in servo circuits -- we anticipate that these devices, which have masses in the 1--10 {mu}g range, will resolve sub-mG signals. Concurrently, we are developing a novel ``mold`` micromachining technology that promises to make proof masses in the 1--10 mg range possible -- our calculations indicate that devices made in this new technology will resolve down to at least sub-{mu}G signals, and may even approach to 10{sup {minus}10} G/{radical}Hz acceleration levels found in the low-earth-noise model.

  16. Kinetic energy transducing system

    SciTech Connect

    Danihel, M.

    1986-07-08

    A device is described for converting wave energy to mechanical motion comprising: a frame, at least one wave energy transducer each of which has a float to ride upon the undulating surface of a body of water, a rocker shaft rotatably mounted in the frame and connected to the float by a rocker arm to turn in response to movement of the float upon the undulating water surface, a pair of unidirectional clutch mechanisms coupled to the rocker shaft, a drive shaft rotatably mounted on the frame and connected to the clutch mechanisms to turn in a single direction of rotation responsive to alternative engagement of the clutch mechanisms therewith and turning movement of the rocker shaft in both directions of rotation, and a hydrofoil system for each float including a vertical shaft extending downwardly from the bottom of each float, a transverse rod which is rotatably coupled to the vertical shaft, a pair of hydrofoil wings secured to the transverse rod on opposite sides of the vertical shaft, and means for centering the hydrofoil wings acting between the vertical shaft and the transverse rod to urge the hydrofoil wings toward horizontal orientation.

  17. Passive wireless ultrasonic transducer systems

    NASA Astrophysics Data System (ADS)

    Zhong, C. H.; Croxford, A. J.; Wilcox, P. D.

    2014-02-01

    Inductive coupling and capacitive coupling both offer simple solutions to wirelessly probe ultrasonic transducers. This paper investigates the theory and feasibility of such system in the context of non-destructive evaluation (NDE) applications. Firstly, the physical principles and construction of an inductively coupled transducer system (ICTS) and a capacitively coupled transducer system (CCTS) are introduced. Then the development of a transmission line model with the measured impedance of a bonded piezoelectric ceramic disc representing a sensor attached to an arbitrary solid substrate for both systems is described. The models are validated experimentally. Several applications of CCTS are presented, such CCTS for the underwater and through-composite testing.

  18. Feasibility of Rotational Scan Ultrasound Imaging by an Angled High Frequency Transducer for the Posterior Segment of the Eye

    PubMed Central

    Paeng, Dong-Guk; Chang, Jin Ho; Chen, Ruimin; Humayun, Mark S.; Shung, K. Kirk

    2009-01-01

    High frequency ultrasound over 40 MHz has been used to image the anterior segment of the eye, but it is not suitable for the posterior segment due to the frequency-dependent attenuation of ultrasound and thus the limitation of penetration depth. This paper proposes a novel scan method to image the posterior segment of the eye with an angled high frequency (beyond 40 MHz) ultrasound needle transducer. In this method, the needle transducer is inserted into the eye through a small incision hole (∼1 mm in diameter) and rotated around the axial direction to form a cone-shaped imaging plane, allowing the spatial information of retinal vessels and diagnosis of their occlusion to be displayed. The feasibility of this novel technique was tested with images of a wire phantom, a polyimide tube, and an excised pig eye obtained by manually rotating a 40-MHz PMN-PT needle transducer with a beveled tip of 45°. From the results, we believe that rotational scan imaging will help expand the minimally invasive applications of high frequency ultrasound to other areas due to the capability of increased closeness of an angled needle transducer to structures of interest buried in other tissues. PMID:19411226

  19. Feasibility of rotational scan ultrasound imaging by an angled high frequency transducer for the posterior segment of the eye.

    PubMed

    Paeng, Dong-Guk; Chang, Jin Ho; Chen, Ruimin; Humayun, Mark S; Shung, K Kirk

    2009-03-01

    High frequency ultrasound over 40 MHz has been used to image the anterior segment of the eye, but it is not suitable for the posterior segment due to the frequency dependent attenuation of ultrasound and thus the limitation of penetration depth. This paper proposes a novel scan method to image the posterior segment of the eye with an angled high frequency (beyond 40 MHz) ultrasound needle transducer. In this method, the needle transducer is inserted into the eye through a small incision hole (approximately 1 mm in diameter) and rotated around the axial direction to form a cone-shaped imaging plane, allowing the spatial information of retinal vessels and diagnosis of their occlusion to be displayed. The feasibility of this novel technique was tested with images of a wire phantom, a polyimide tube, and an excised pig eye obtained by manually rotating a 40-MHz PMN-PT needle transducer with a beveled tip of 45 degrees . From the results, we believe that rotational scan imaging will help expand the minimally invasive applications of high frequency ultrasound to other areas due to the capability of increased closeness of an angled needle transducer to structures of interest buried in other tissues.

  20. Fixture for holding testing transducer

    DOEpatents

    Wagner, T.A.; Engel, H.P.

    A fixture for mounting an ultrasonic transducer against the end of a threaded bolt or stud to test the same for flaws. A base means threadedly secured to the side of the bolt has a rotating ring thereon. A post rising up from the ring (parallel to the axis of the workpiece) pivotally mounts a variable length cross arm, on the inner end of which is mounted the transducer. A spring means acts between the cross arm and the base to apply the testing transducer against the workpiece at a constant pressure. The device maintains constant for successive tests the radial and circumferential positions of the testing transducer and its contact pressure against the end of the workpiece.

  1. Fixture for holding testing transducer

    DOEpatents

    Wagner, Thomas A.; Engel, Herbert P.

    1984-01-01

    A fixture for mounting an ultrasonic transducer against the end of a threaded bolt or stud to test the same for flaws. A base means threadedly secured to the side of the bolt has a rotating ring thereon. A post rising up from the ring (parallel to the axis of the workpiece) pivotally mounts a variable length cross arm, on the inner end of which is mounted the transducer. A spring means acts between the cross arm and the base to apply the testing transducer against the workpiece at a constant pressure. The device maintains constant for successive tests the radial and circumferential positions of the testing transducer and its contact pressure against the end of the workpiece.

  2. TRANSDUCER FIELD IMAGING USING ACOUSTOGRAPHY

    PubMed Central

    Sandhu, Jaswinder S.; Schoonover, Robert W.; Weber, Joshua I.; Tawiah, J.; Kunin, Vitaliy; Anastasio, Mark A.

    2013-01-01

    A common current practice for transducer field mapping is to scan, point-by-point, a hydrophone element in a 2D raster at various distances from the transducer radiating surface. This approach is tedious, requiring hours of scanning time to generate full cross-sectional and/or axial field distributions. Moreover, the lateral resolution of the field distribution image is dependent on the indexing steps between data points. Acoustography is an imaging process in which an acousto-optical (AO) area sensor is employed to record the intensity of an ultrasound wavefield on a two-dimensional plane. This paper reports on the application of acoustography as a simple but practical method for assessing transducer field characteristics. A case study performed on a commercial transducer is reported, where the radiated fields are imaged using acoustography and compared to the corresponding quantities that are predicted numerically. PMID:23967016

  3. An enzyme logic bioprotonic transducer

    SciTech Connect

    Miyake, Takeo; Keene, Scott; Deng, Yingxin; Rolandi, Marco; Josberger, Erik E.

    2015-01-01

    Translating ionic currents into measureable electronic signals is essential for the integration of bioelectronic devices with biological systems. We demonstrate the use of a Pd/PdH{sub x} electrode as a bioprotonic transducer that connects H{sup +} currents in solution into an electronic signal. This transducer exploits the reversible formation of PdH{sub x} in solution according to PdH↔Pd + H{sup +} + e{sup −}, and the dependence of this formation on solution pH and applied potential. We integrate the protonic transducer with glucose dehydrogenase as an enzymatic AND gate for glucose and NAD{sup +}. PdH{sub x} formation and associated electronic current monitors the output drop in pH, thus transducing a biological function into a measurable electronic output.

  4. An enzyme logic bioprotonic transducer

    NASA Astrophysics Data System (ADS)

    Miyake, Takeo; Josberger, Erik E.; Keene, Scott; Deng, Yingxin; Rolandi, Marco

    2015-01-01

    Translating ionic currents into measureable electronic signals is essential for the integration of bioelectronic devices with biological systems. We demonstrate the use of a Pd/PdHx electrode as a bioprotonic transducer that connects H+ currents in solution into an electronic signal. This transducer exploits the reversible formation of PdHx in solution according to PdH↔Pd + H+ + e-, and the dependence of this formation on solution pH and applied potential. We integrate the protonic transducer with glucose dehydrogenase as an enzymatic and gate for glucose and NAD+. PdHx formation and associated electronic current monitors the output drop in pH, thus transducing a biological function into a measurable electronic output.

  5. Acoustic transducer with damping means

    DOEpatents

    Smith, Richard W.; Adamson, Gerald E.

    1976-11-02

    An ultrasonic transducer specifically suited to high temperature sodium applications is described. A piezoelectric active element is joined to the transducer faceplate by coating the faceplate and juxtaposed active element face with wetting agents specifically compatible with the bonding procedure employed to achieve the joint. The opposite face of the active element is fitted with a backing member designed to assure continued electrical continuity during adverse operating conditions which can result in the fracturing of the active element. The fit is achieved employing a spring-loaded electrode operably arranged to electrically couple the internal transducer components, enclosed in a hermetically sealed housing, to accessory components normally employed in transducer applications. Two alternative backing members are taught for assuring electrical continuity. The first employs a resilient, discrete multipoint contact electrode in electrical communication with the active element face. The second employs a resilient, elastomeric, electrically conductive, damped member in electrical communication with the active element face in a manner to effect ring-down of the transducer. Each embodiment provides continued electrical continuity within the transducer in the event the active element fractures, while the second provides the added benefit of damping.

  6. Thermal Wick Cooling for Vibroacoustic Transducers

    DTIC Science & Technology

    2009-09-25

    affecting vibrational characteristics of the transducer . (2) Description of the Prior Art [0004] Vibroacoustic transducers , such as piezoceramic tonpilz ...Distribution is unlimited 20091013084 Attorney Docket No. 84708 THERMAL WICK COOLING FOR VIBROACOUSTIC TRANSDUCERS STATEMENT OF GOVERNMENT INTEREST...INVENTION (1) Field of the Invention [0003] The present invention provides a device for cooling a vibroacoustic transducer without adversely

  7. Ultrasonic Transducer Irradiation Test Results

    SciTech Connect

    Daw, Joshua; Palmer, Joe; Ramuhalli, Pradeep; Keller, Paul; Montgomery, Robert; Chien, Hual-Te; Kohse, Gordon; Tittmann, Bernhard; Reinhardt, Brian; Rempe, Joy

    2015-02-01

    Ultrasonic technologies offer the potential for high-accuracy and -resolution in-pile measurement of a range of parameters, including geometry changes, temperature, crack initiation and growth, gas pressure and composition, and microstructural changes. Many Department of Energy-Office of Nuclear Energy (DOE-NE) programs are exploring the use of ultrasonic technologies to provide enhanced sensors for in-pile instrumentation during irradiation testing. For example, the ability of small diameter ultrasonic thermometers (UTs) to provide a temperature profile in candidate metallic and oxide fuel would provide much needed data for validating new fuel performance models. Other ongoing efforts include an ultrasonic technique to detect morphology changes (such as crack initiation and growth) and acoustic techniques to evaluate fission gas composition and pressure. These efforts are limited by the lack of identified ultrasonic transducer materials capable of long term performance under irradiation test conditions. For this reason, the Pennsylvania State University (PSU) was awarded an ATR NSUF project to evaluate the performance of promising magnetostrictive and piezoelectric transducers in the Massachusetts Institute of Technology Research Reactor (MITR) up to a fast fluence of at least 1021 n/cm2. The goal of this research is to characterize and demonstrate magnetostrictive and piezoelectric transducer operation during irradiation, enabling the development of novel radiation-tolerant ultrasonic sensors for use in Material Testing Reactors (MTRs). As such, this test is an instrumented lead test and real-time transducer performance data is collected along with temperature and neutron and gamma flux data. The current work bridges the gap between proven out-of-pile ultrasonic techniques and in-pile deployment of ultrasonic sensors by acquiring the data necessary to demonstrate the performance of ultrasonic transducers. To date, one piezoelectric

  8. Auto-positioning ultrasonic transducer system

    NASA Technical Reports Server (NTRS)

    Buchanan, Randy K. (Inventor)

    2010-01-01

    An ultrasonic transducer apparatus and process for determining the optimal transducer position for flow measurement along a conduit outer surface. The apparatus includes a transmitting transducer for transmitting an ultrasonic signal, said transducer affixed to a conduit outer surface; a guide rail attached to a receiving transducer for guiding movement of a receiving transducer along the conduit outer surface, wherein the receiving transducer receives an ultrasonic signal from the transmitting transducer and sends a signal to a data acquisition system; and a motor for moving the receiving transducer along the guide rail, wherein the motor is controlled by a controller. The method includes affixing a transmitting transducer to an outer surface of a conduit; moving a receiving transducer on the conduit outer surface, wherein the receiving transducer is moved along a guide rail by a motor; transmitting an ultrasonic signal from the transmitting transducer that is received by the receiving transducer; communicating the signal received by the receiving transducer to a data acquisition and control system; and repeating the moving, transmitting, and communicating along a length of the conduit.

  9. Radially sandwiched cylindrical piezoelectric transducer

    NASA Astrophysics Data System (ADS)

    Lin, Shuyu; Fu, Zhiqiang; Zhang, Xiaoli; Wang, Yong; Hu, Jing

    2013-01-01

    A new type of radially sandwiched piezoelectric short cylindrical transducer is developed and its radial vibration is studied. The transducer is composed of a solid metal disk, a radially polarized piezoelectric ceramic short tube and a metal tube. The radial vibrations of the solid metal disk, the radially polarized piezoelectric tube and the metal tube are analyzed and their electromechanical equivalent circuits are introduced. Based on the mechanical boundary conditions among the metal disk, the piezoelectric tube and the metal tube, a three-port electromechanical equivalent circuit for the radially sandwiched transducer is obtained and the frequency equation is given. The theoretical relationship of the resonance and anti-resonance frequencies and the effective electromechanical coupling coefficient with the geometrical dimensions is analyzed. The radial vibration of the sandwiched transducer is simulated by using two different numerical methods. It is shown that the analytical resonance and anti-resonance frequencies are in good agreement with the numerically simulated results. The transducer is expected to be used in piezoelectric resonators, actuators and ultrasonic radiators in ultrasonic and underwater sound applications.

  10. 21 CFR 880.5580 - Acupuncture needle.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Acupuncture needle. 880.5580 Section 880.5580 Food... § 880.5580 Acupuncture needle. (a) Identification. An acupuncture needle is a device intended to pierce the skin in the practice of acupuncture. The device consists of a solid, stainless steel needle....

  11. 21 CFR 880.5580 - Acupuncture needle.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Acupuncture needle. 880.5580 Section 880.5580 Food... § 880.5580 Acupuncture needle. (a) Identification. An acupuncture needle is a device intended to pierce the skin in the practice of acupuncture. The device consists of a solid, stainless steel needle....

  12. 21 CFR 880.5580 - Acupuncture needle.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Acupuncture needle. 880.5580 Section 880.5580 Food... § 880.5580 Acupuncture needle. (a) Identification. An acupuncture needle is a device intended to pierce the skin in the practice of acupuncture. The device consists of a solid, stainless steel needle....

  13. 21 CFR 880.5580 - Acupuncture needle.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Acupuncture needle. 880.5580 Section 880.5580 Food... § 880.5580 Acupuncture needle. (a) Identification. An acupuncture needle is a device intended to pierce the skin in the practice of acupuncture. The device consists of a solid, stainless steel needle....

  14. 21 CFR 880.5580 - Acupuncture needle.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Acupuncture needle. 880.5580 Section 880.5580 Food... § 880.5580 Acupuncture needle. (a) Identification. An acupuncture needle is a device intended to pierce the skin in the practice of acupuncture. The device consists of a solid, stainless steel needle....

  15. Iron needles in supernova remnants?

    NASA Astrophysics Data System (ADS)

    Gomez (née Morgan), Haley L.; Dunne, Loretta; Eales, Stephen A.; Gomez, Edward L.; Edmunds, Michael G.

    2005-08-01

    It has been suggested by Dwek that iron needles could explain the submillimetre emission from the Cas A supernova remnant (SNR) with only a very small total mass. We investigate whether a similar model holds for the Kepler SNR, and find that its emission could indeed be explained by a dust mass of less than 10-2Msolar, dependent on the axial ratio l/a of the needles - which we constrain to be less than 700. But the implied needle model for Kepler is inconsistent with that suggested for Cas A since either the needles would have to have a resistivity one or two orders of magnitude greater than those in Cas A or the electron density in Kepler's shocked plasma must be 40 times greater than suggested by X-ray observations. An additional problem with the needle model is that the implied thickness of the needles seems to be implausibly small, if the emission properties are calculated under the usual approximations.

  16. Fabrication of tungsten wire needles

    SciTech Connect

    Roder, A.

    1983-02-01

    Fine point needles for field emissoin are conventionally produced by electrolytically or chemically etching tungsten wire. Points formed in this manner have a typical tip radius of about 0.5 microns and a cone angle of some 30 degrees. The construction of needle matrix detector chambers has created a need for tungsten needles whose specifications are: 20 mil tungsten wire, 1.5 inch total length, 3 mm-long taper (resulting in a cone angle of about 5 degrees), and 25 micron-radius point (similar to that found on sewing needles). In the process described here for producing such needles, tungsten wire, immersed in a NaOH solution and in the presence of an electrode, is connected first to an ac voltage and then to a dc supply, to form a taper and a point on the end of the wire immersed in the solution. The process parameters described here are for needles that will meet the above specifications. Possible variations will be discussed under each approprite heading.

  17. Model of a Piezoelectric Transducer

    NASA Technical Reports Server (NTRS)

    Goodenow, Debra

    2004-01-01

    It's difficult to control liquid and gas in propellant tanks in zero gravity. A possible a design would utilize acoustic liquid manipulation (ALM) technology which uses ultrasonic beams conducted through a liquid and solid media, to push gas bubbles in the liquid to desirable locations. We can propel and control the bubble with acoustic radiation pressure by aiming the acoustic waves on the bubble s surface. This allows us to design a so called smart tank in which the ALM devices transfer the gas to the outer wall of the tank and isolating the liquid in the center. Because the heat transfer rate of a gas is lower of that of the liquid it would substantially decrease boil off and provide of for a longer storage life. The ALM beam is composed of little wavelets which are individual waves that constructively interfere with each other to produce a single, combined acoustic wave front. This is accomplished by using a set of synchronized ultrasound transducers arranged in an array. A slight phase offset of these elements allows us to focus and steer the beam. The device that we are using to produce the acoustic beam is called the piezoelectric transducer. This device converts electrical energy to mechanical energy, which appears in the form of acoustic energy. Therefore the behavior of the device is dependent on both the mechanical characteristics, such as its density, cross-sectional area, and its electrical characteristics, such as, electric flux permittivity and coupling factor. These devices can also be set up in a number of modes which are determined by the way the piezoelectric device is arranged, and the shape of the transducer. For this application we are using the longitudinal or thickness mode for our operation. The transducer also vibrates in the lateral mode, and one of the goals of my project is to decrease the amount of energy lost to the lateral mode. To model the behavior of the transducers I will be using Pspice, electric circuit modeling tool, to

  18. Environmental control system transducer development study

    NASA Technical Reports Server (NTRS)

    Brudnicki, M. J.

    1973-01-01

    A failure evaluation of the transducers used in the environmental control systems of the Apollo command service module, lunar module, and portable life support system is presented in matrix form for several generic categories of transducers to enable identification of chronic failure modes. Transducer vendors were contacted and asked to supply detailed information. The evaluation data generated for each category of transducer were compiled and published in failure design evaluation reports. The evaluation reports also present a review of the failure and design data for the transducers and suggest both design criteria to improve reliability of the transducers and, where necessary, design concepts for required redesign of the transducers. Remedial designs were implemented on a family of pressure transducers and on the oxygen flow transducer. The design concepts were subjected to analysis, breadboard fabrication, and verification testing.

  19. Multi sensor transducer and weight factor

    NASA Technical Reports Server (NTRS)

    Immer, Christopher D. (Inventor); Lane, John (Inventor); Eckhoff, Anthony J. (Inventor); Perotti, Jose M. (Inventor)

    2004-01-01

    A multi-sensor transducer and processing method allow insitu monitoring of the senor accuracy and transducer `health`. In one embodiment, the transducer has multiple sensors to provide corresponding output signals in response to a stimulus, such as pressure. A processor applies individual weight factors to reach of the output signals and provide a single transducer output that reduces the contribution from inaccurate sensors. The weight factors can be updated and stored. The processor can use the weight factors to provide a `health` of the transducer based upon the number of accurate versus in-accurate sensors in the transducer.

  20. Pressure-Coupled Acoustic-Transducer Assembly

    NASA Technical Reports Server (NTRS)

    Parker, F. Raymond

    1993-01-01

    Improved acoustic-transducer assembly easy to assemble, relocatable, and used at high temperatures. In assembly, piezoelectric acoustic transducer pressure-coupled to delay line or fixture through soft metal like aluminum, copper or gold. Transducer subassembly includes layered structure of coupling material, transducer, thin disk of coupling material acting as cushion for transducer, electrode disk with coaxial cable lead attached, insulation/damping material, and pressure plate. Pressure coupling precludes problem of matching coefficients of thermal expansion of transducer, coupling material, and delay line.

  1. Non-bonded ultrasonic transducer

    DOEpatents

    Eoff, J.M.

    1984-07-06

    A mechanically assembled non-bonded ultrasonic transducer includes a substrate, a piezoelectric film, a wetting agent, a thin metal electrode, and a lens held in intimate contact by a mechanical clamp. No epoxy or glue is used in the assembly of this device.

  2. Acoustic transducer for acoustic microscopy

    DOEpatents

    Khuri-Yakub, Butrus T.; Chou, Ching H.

    1990-01-01

    A shear acoustic transducer-lens system in which a shear polarized piezoelectric material excites shear polarized waves at one end of a buffer rod having a lens at the other end which excites longitudinal waves in a coupling medium by mode conversion at selected locations on the lens.

  3. Acoustic transducer for acoustic microscopy

    DOEpatents

    Khuri-Yakub, B.T.; Chou, C.H.

    1990-03-20

    A shear acoustic transducer-lens system is described in which a shear polarized piezoelectric material excites shear polarized waves at one end of a buffer rod having a lens at the other end which excites longitudinal waves in a coupling medium by mode conversion at selected locations on the lens. 9 figs.

  4. Calibration apparatus for recess mounted pressure transducers

    NASA Astrophysics Data System (ADS)

    Marcolini, Michael A.; Miller, William T., Jr.; Baals, Robert A.; Martin, Ruth M.

    1992-04-01

    Measurement of surface pressure fluctuations is important in aerodynamic studies and is conventionally accomplished via thin surface mounted transducers. These transducers contaminate the airflow, leading to the use of transducers located beneath the surface and communicating thereto via a pipette. This solution creates its own problem of transducer calibration due to the structure of the pipette. A calibration apparatus and method for calibrating a pressure transducer are provided. The pressure transducer is located within a test structure having a pipette leading from an outer structure surface to the pressure transducer. The calibration apparatus defines an acoustic cavity. A first end of the acoustic cavity is adapted to fluidly communicate with the pipette leading to the pressure transducer, wherein a channel is formed from the acoustic cavity to the transducer. An acoustic driver is provided for acoustically exciting fluid in the acoustic cavity to generate pressure waves which propagate to the pressure transducer. A pressure sensing microphone is provided for sensing the pressure fluctuations in the cavity near the cavity end, whereby this sensed pressure is compared with a simultaneously pressure sensed by the pressure transducer to permit calibration of the pressure transducer sensings. Novel aspects of the present invention include its use of a calibration apparatus to permit in-situ calibration of recess mounted pressure transducers.

  5. PMN-PT single crystal thick films on silicon substrate for high-frequency micromachined ultrasonic transducers.

    PubMed

    Peng, J; Lau, S T; Chao, C; Dai, J Y; Chan, H L W; Luo, H S; Zhu, B P; Zhou, Q F; Shung, K K

    2008-11-02

    In this work, a novel high-frequency ultrasonic transducer structure is realized by using PMNPT-on-silicon technology and silicon micromachining. To prepare the single crystalline PMNPT-on-silicon wafers, a hybrid processing method involving wafer bonding, mechanical lapping and wet chemical thinning is successfully developed. In the transducer structure, the active element is fixed within the stainless steel needle housing. The measured center frequency and -6 dB bandwidth of the transducer are 35 MHz and 34%, respectively. Owing to the superior electromechanical coupling coefficient (k(t)) and high piezoelectric constant (d(33)) of PMNPT film, the transducer shows a good energy conversion performance with a very low insertion loss down to 8.3 dB at the center frequency.

  6. Interactive simulation of needle insertion models.

    PubMed

    DiMaio, Simon P; Salcudean, Septimiu E

    2005-07-01

    A novel interactive virtual needle insertion simulation is presented. The simulation models are based on measured planar tissue deformations and needle insertion forces. Since the force-displacement relationship is only of interest along the needle shaft, a condensation technique is shown to reduce the computational complexity of linear simulation models significantly. As the needle penetrates or is withdrawn from the tissue model, the boundary conditions that determine the tissue and needle motion change. Boundary condition and local material coordinate changes are facilitated by fast low-rank matrix updates. A large-strain elastic needle model is coupled to the tissue models to account for needle deflection and bending during simulated insertion. A haptic environment, based on these novel interactive simulation techniques, allows users to manipulate a three-degree-of-freedom virtual needle as it penetrates virtual tissue models, while experiencing steering torques and lateral needle forces through a planar haptic interface.

  7. Irradiation Testing of Ultrasonic Transducers

    SciTech Connect

    Daw, Joshua; Tittmann, Bernhard; Reinhardt, Brian; Kohse, Gordon E.; Ramuhalli, Pradeep; Montgomery, Robert O.; Chien, Hual-Te; Villard, Jean-Francois; Palmer, Joe; Rempe, Joy

    2014-07-30

    Ultrasonic technologies offer the potential for high accuracy and resolution in-pile measurement of a range of parameters, including geometry changes, temperature, crack initiation and growth, gas pressure and composition, and microstructural changes. Many Department of Energy-Office of Nuclear Energy (DOE-NE) programs are exploring the use of ultrasonic technologies to provide enhanced sensors for in-pile instrumentation during irradiation testing. For example, the ability of single, small diameter ultrasonic thermometers (UTs) to provide a temperature profile in candidate metallic and oxide fuel would provide much needed data for validating new fuel performance models. Other efforts include an ultrasonic technique to detect morphology changes (such as crack initiation and growth) and acoustic techniques to evaluate fission gas composition and pressure. These efforts are limited by the lack of existing knowledge of ultrasonic transducer material survivability under irradiation conditions. For this reason, the Pennsylvania State University (PSU) was awarded an Advanced Test Reactor National Scientific User Facility (ATR NSUF) project to evaluate promising magnetostrictive and piezoelectric transducer performance in the Massachusetts Institute of Technology Research Reactor (MITR) up to a fast fluence of at least 1021 n/cm2 (E> 0.1 MeV). The goal of this research is to characterize magnetostrictive and piezoelectric transducer survivability during irradiation, enabling the development of novel radiation tolerant ultrasonic sensors for use in Material and Test Reactors (MTRs). As such, this test will be an instrumented lead test and real-time transducer performance data will be collected along with temperature and neutron and gamma flux data. The current work bridges the gap between proven out-of-pile ultrasonic techniques and in-pile deployment of ultrasonic sensors by acquiring the data necessary to demonstrate the performance of ultrasonic transducers.

  8. Irradiation Testing of Ultrasonic Transducers

    SciTech Connect

    Daw, Joshua; Tittmann, Bernhard; Reinhardt, Brian; Kohse, Gordon E.; Ramuhalli, Pradeep; Montgomery, Robert O.; Chien, Hual-Te; Villard, Jean-Francois; Palmer, Joe; Rempe, Joy

    2013-12-01

    Ultrasonic technologies offer the potential for high accuracy and resolution in-pile measurement of a range of parameters, including geometry changes, temperature, crack initiation and growth, gas pressure and composition, and microstructural changes. Many Department of Energy-Office of Nuclear Energy (DOE-NE) programs are exploring the use of ultrasonic technologies to provide enhanced sensors for in-pile instrumentation during irradiation testing. For example, the ability of single, small diameter ultrasonic thermometers (UTs) to provide a temperature profile in candidate metallic and oxide fuel would provide much needed data for validating new fuel performance models. Other efforts include an ultrasonic technique to detect morphology changes (such as crack initiation and growth) and acoustic techniques to evaluate fission gas composition and pressure. These efforts are limited by the lack of existing knowledge of ultrasonic transducer material survivability under irradiation conditions. For this reason, the Pennsylvania State University (PSU) was awarded an Advanced Test Reactor National Scientific User Facility (ATR NSUF) project to evaluate promising magnetostrictive and piezoelectric transducer performance in the Massachusetts Institute of Technology Research Reactor (MITR) up to a fast fluence of at least 1021 n/cm2 (E> 0.1 MeV). The goal of this research is to characterize magnetostrictive and piezoelectric transducer survivability during irradiation, enabling the development of novel radiation tolerant ultrasonic sensors for use in Material and Test Reactors (MTRs). As such, this test will be an instrumented lead test and real-time transducer performance data will be collected along with temperature and neutron and gamma flux data. The current work bridges the gap between proven out-of-pile ultrasonic techniques and in-pile deployment of ultrasonic sensors by acquiring the data necessary to demonstrate the performance of ultrasonic transducers.

  9. Pressure transducer for measuring acoustic radiation force based on a magnetic sensor

    NASA Astrophysics Data System (ADS)

    Kamimura, H. A. S.; Pavan, T. Z.; Almeida, T. W. J.; Pádua, M. L. A.; Baggio, A. L.; Fatemi, M.; Carneiro, A. A. O.

    2011-01-01

    This work presents a pressure transducer based on a magnetic sensor to measure acoustic radiation force (ARF) and small displacements. The methodology presented in this paper allowed this transducer to be calibrated for use as an acoustic pressure and intensity meter. It can control the acoustic intensity emitted by ultrasound used, for example, in ARF impulse imaging, vibro-acoustography and high-intensity focused ultrasound techniques. The device comprises a magnet, a membrane, a magnetoresistive sensor and a coil to cancel the external magnetic field. When ARF is applied to the membrane, the magnetic field on the sensor changes due to the magnetic target displacement. The variation of the output signal from the magnetic transducer is proportional to the acoustic pressure applied to the membrane. A focused ultrasound transducer with a central frequency of 3 MHz was used to apply a continuous ARF. The sensitivities of the magnetic transducer as an acoustic pressure and intensity meter, evaluated in water, were respectively 0.597 µV MPa-1 and 0.073 µV (W cm-2)-1/2, while those of the needle hydrophone (Onda model HNP-0400) used in the magnetic transducer calibration were respectively, 0.5024 mV MPa-1 and 6.153 mV (W cm-2)-1/2. The transducer resolution to displacement is 5 nm and 6 dB of signal attenuation occurs for 7° of misalignment. The transducer responded well to acoustic pressure in water above 200 kPa.

  10. Wideband Single Crystal Transducer for Bone Characterization

    NASA Technical Reports Server (NTRS)

    Sahul, Raffi

    2015-01-01

    Phase II objectives: Optimize the Phase I transducer for sensitivity; Test different transmit signals for optimum performance; Demonstrate compatibility with electronics; Confirm additional transducer capabilities over conventional systems by calibrating with other methods.

  11. Cooling Acoustic Transducer with Heat Pipes

    DTIC Science & Technology

    2009-07-29

    0013] Most transducer packages involve a stack of active ceramic. A Tonpilz transducer 10 in the prior art, as depicted in FIG. 1, consists...or corresponding parts throughout the several views and wherein: [0023] FIG. 1 is a prior art depiction of a Tonpilz transducer design; [0024...Distribution is unlimited Attorney Docket No. 97001 COOLING ACOUSTIC TRANSDUCER WITH HEAT PIPES STATEMENT OF GOVERNMENT INTEREST [0001] The

  12. Acoustic Emission Transducers: Calibration Activities and Transducer Development.

    DTIC Science & Technology

    2014-09-26

    transducer calibration and development activities -j at NBS is summiarized. DO Fo"� roiion or olv as is OBSOLETE DOS/N 0 102. LP.60 4. 6601...developed. This development was partially supported by the Electric Power Research Institute and the Office of Naval Research. The calibration subjects the...and tangential components of motion must be measured tb describe the dynamic displacement at a point on a surface. We previously have developed the NBS

  13. 21 CFR 882.1950 - Tremor transducer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Tremor transducer. 882.1950 Section 882.1950 Food... DEVICES NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1950 Tremor transducer. (a) Identification. A tremor transducer is a device used to measure the degree of tremor caused by certain...

  14. 21 CFR 882.1950 - Tremor transducer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Tremor transducer. 882.1950 Section 882.1950 Food... DEVICES NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1950 Tremor transducer. (a) Identification. A tremor transducer is a device used to measure the degree of tremor caused by certain...

  15. 21 CFR 882.1950 - Tremor transducer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Tremor transducer. 882.1950 Section 882.1950 Food... DEVICES NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1950 Tremor transducer. (a) Identification. A tremor transducer is a device used to measure the degree of tremor caused by certain...

  16. 21 CFR 882.1950 - Tremor transducer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Tremor transducer. 882.1950 Section 882.1950 Food... DEVICES NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1950 Tremor transducer. (a) Identification. A tremor transducer is a device used to measure the degree of tremor caused by certain...

  17. 21 CFR 882.1950 - Tremor transducer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Tremor transducer. 882.1950 Section 882.1950 Food... DEVICES NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1950 Tremor transducer. (a) Identification. A tremor transducer is a device used to measure the degree of tremor caused by certain...

  18. 21 CFR 870.2880 - Ultrasonic transducer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Ultrasonic transducer. 870.2880 Section 870.2880...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2880 Ultrasonic transducer. (a) Identification. An ultrasonic transducer is a device applied to the skin to transmit and...

  19. 21 CFR 870.2880 - Ultrasonic transducer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ultrasonic transducer. 870.2880 Section 870.2880...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2880 Ultrasonic transducer. (a) Identification. An ultrasonic transducer is a device applied to the skin to transmit and...

  20. Does Needle Rotation Improve Lesion Targeting?

    PubMed Central

    Badaan, Shadi; Petrisor, Doru; Kim, Chunwoo; Mozer, Pierre; Mazilu, Dumitru; Gruionu, Lucian; Patriciu, Alex; Cleary, Kevin; Stoianovici, Dan

    2011-01-01

    Background Image-guided robots are manipulators that operate based on medical images. Perhaps the most common class of image-guided robots are robots for needle interventions. Typically, these robots actively position and/or orient a needle guide, but needle insertion is still done by the physician. While this arrangement may have safety advantages and keep the physician in control of needle insertion, actuated needle drivers can incorporate other useful features. Methods We first present a new needle driver that can actively insert and rotate a needle. With this device we investigate the use of needle rotation in controlled in-vitro experiments performed with a specially developed revolving needle driver. Results These experiments show that needle rotation can improve targeting and may reduce errors by as much as 70%. Conclusion The new needle driver provides a unique kinematic architecture that enables insertion with a compact mechanism. Perhaps the most interesting conclusion of the study is that lesions of soft tissue organs may not be perfectly targeted with a needle without using special techniques, either manually or with a robotic device. The results of this study show that needle rotation may be an effective method of reducing targeting errors. PMID:21360796

  1. Superficial versus deep dry needling.

    PubMed

    Baldry, Peter

    2002-08-01

    Ninety percent of my patients with myofascial trigger point (MTrP) pain have this alone and are treated with superficial dry needling. Approximately 10% have concomitant MTrP pain and nerve root compression pain. These are treated with deep dry needling. SUPERFICIAL DRY NEEDLING (SDN): The activated and sensitised nociceptors of a MTrP cause it to be so exquisitely tender that firm pressure applied to it gives rise to a flexion withdrawal reflex (jump sign) and in some cases the utterance of an expletive (shout sign). The optimum strength of SDN at a MTrP site is the minimum necessary to abolish these two reactions. With respect to this patients are divided into strong, average and weak responders. The responsiveness of each individual is determined by trial and error. It is my practice to insert a needle (0.3mm x 30mm) into the tissues immediately overlying the MTrP to a depth of 5-10 mm and to leave it in situ long enough for the two reactions to be abolished. For an average reactor this is about 30secs. For a weak reactor it is several minutes. And for a strong reactor the insertion of the needle and its immediate withdrawal is all that is required. Following treatment muscle stretching exercises should be carried out, and any steps taken to eliminate factors that might lead to the reactivation of the MTrPs. DEEP DRY NEEDLING (DDN): This in my practice is only used either when primary MTrP activity causes shortening of muscle sufficient enough to bring about compression of nerve roots. Or when there is nerve compression pain usually from spondylosis or disc prolapse and the secondary development of MTrP activity. Unlike SDN, DDN is a painful procedure and one which gives rise to much post-treatment soreness.

  2. Magnetic needles and superparamagnetic cells

    PubMed Central

    Bryant, H C; Sergatskov, D A; Lovato, Debbie; Adolphi, Natalie L; Larson, Richard S; Flynn, Edward R

    2007-01-01

    Superparamagnetic nanoparticles can be attached in great numbers to pathogenic cells using specific antibodies so that the magnetically-labeled cells themselves become superparamagnets. The cells can then be manipulated and drawn out of biological fluids, as in a biopsy, very selectively using a magnetic needle. We examine the origins and uncertainties in the forces exerted on magnetic nanoparticles by static magnetic fields, leading to a model for trajectories and collection times of dilute superparamagnetic cells in biological fluids. We discuss the design and application of such magnetic needles and the theory of collection times. We compare the mathematical model to measurements in a variety of media including blood. PMID:17664592

  3. Self-Calibrating Pressure Transducer

    NASA Technical Reports Server (NTRS)

    Lueck, Dale E. (Inventor)

    2006-01-01

    A self-calibrating pressure transducer is disclosed. The device uses an embedded zirconia membrane which pumps a determined quantity of oxygen into the device. The associated pressure can be determined, and thus, the transducer pressure readings can be calibrated. The zirconia membrane obtains oxygen .from the surrounding environment when possible. Otherwise, an oxygen reservoir or other source is utilized. In another embodiment, a reversible fuel cell assembly is used to pump oxygen and hydrogen into the system. Since a known amount of gas is pumped across the cell, the pressure produced can be determined, and thus, the device can be calibrated. An isolation valve system is used to allow the device to be calibrated in situ. Calibration is optionally automated so that calibration can be continuously monitored. The device is preferably a fully integrated MEMS device. Since the device can be calibrated without removing it from the process, reductions in costs and down time are realized.

  4. A silicon electrostatic ultrasonic transducer

    NASA Astrophysics Data System (ADS)

    Suzuki, Kenichiro; Higuchi, Kohei; Tanigawa, Hiroshi

    1989-11-01

    An electric ultrasonic transducer is developed by using a silicon IC process. Design considerations are first presented to obtain high sensitivity and the desired frequency responses in air. The measured transmitter sensitivity is 19.1 dB (0 dB = 1 microbar/V) at a point 50 cm away from the devices, when the devices are operated at 150 kHz. The receiving sensitivity is 0.47 mV/Pa in the 10-130-kHz range, with bias voltages as low as 30 V. An electronic sector scanning operation is also achieved by time-sequentially driving seven elements arranged in a linear array on the same chip. The results should be helpful in the design of phased-array transducers integrated with electronic scanning circuits.

  5. Advanced Geothermal Optical Transducer (AGOT)

    SciTech Connect

    2004-09-01

    Today's geothermal pressure-temperature measuring tools are short endurance, high value instruments, used sparingly because their loss is a major expense. In this project LEL offered to build and test a rugged, affordable, downhole sensor capable ofretuming an uninterrupted data stream at pressures and of 10,000 psi and temperatures up to 250 C, thus permitting continuous deep-well logging. It was proposed to meet the need by specializing LEL's patented 'Twin Column Transducer' technology to satisfy the demands of geothermal pressure/temperature measurements. TCT transducers have very few parts, none of which are moving parts, and all of which can be fabricated from high-temperature super alloys or from ceramics; the result is an extremely rugged device, essentially impervious to chemical attack and readily modified to operate at high pressure and temperature. To measure pressure and temperature they capitalize on the relative expansion of optical elements subjected to thermal or mechanical stresses; if one element is maintained at a reference pressure while the other is opened to ambient, the differential displacement then serves as a measure of pressure. A transducer responding to temperature rather than pressure is neatly created by 'inverting' the pressure-measuring design so that both deflecting structures see identical temperatures and temperature gradients, but whose thermal expansion coefficients are deliberately mismatched to give differential expansion. The starting point for development of a PT Tool was the company's model DPT feedback-stabilized 5,000 psi sensor (U.S. Patent 5,311,014, 'Optical Transducer for Measuring Downhole Pressure', claiming a pressure transducer capable of measuring static, dynamic, and true bi-directional differential pressure at high temperatures), shown in the upper portion of Figure 1. The DPT occupies a 1 x 2 x 4-inch volume, weighs 14 ounces, and is accurate to 1 percent of full scale. Employing a pair of identical, low

  6. Coded excitation ultrasonic needle tracking: An in vivo study

    PubMed Central

    Xia, Wenfeng; Ginsberg, Yuval; West, Simeon J.; Nikitichev, Daniil I.; Ourselin, Sebastien; David, Anna L.; Desjardins, Adrien E.

    2016-01-01

    Purpose Accurate and efficient guidance of medical devices to procedural targets lies at the heart of interventional procedures. Ultrasound imaging is commonly used for device guidance, but determining the location of the device tip can be challenging. Various methods have been proposed to track medical devices during ultrasound-guided procedures, but widespread clinical adoption has remained elusive. With ultrasonic tracking, the location of a medical device is determined by ultrasonic communication between the ultrasound imaging probe and a transducer integrated into the medical device. The signal-to-noise ratio (SNR) of the transducer data is an important determinant of the depth in tissue at which tracking can be performed. In this paper, the authors present a new generation of ultrasonic tracking in which coded excitation is used to improve the SNR without spatial averaging. Methods A fiber optic hydrophone was integrated into the cannula of a 20 gauge insertion needle. This transducer received transmissions from the ultrasound imaging probe, and the data were processed to obtain a tracking image of the needle tip. Excitation using Barker or Golay codes was performed to improve the SNR, and conventional bipolar excitation was performed for comparison. The performance of the coded excitation ultrasonic tracking system was evaluated in an in vivo ovine model with insertions to the brachial plexus and the uterine cavity. Results Coded excitation significantly increased the SNRs of the tracking images, as compared with bipolar excitation. During an insertion to the brachial plexus, the SNR was increased by factors of 3.5 for Barker coding and 7.1 for Golay coding. During insertions into the uterine cavity, these factors ranged from 2.9 to 4.2 for Barker coding and 5.4 to 8.5 for Golay coding. The maximum SNR was 670, which was obtained with Golay coding during needle withdrawal from the brachial plexus. Range sidelobe artifacts were observed in tracking images

  7. Torquemeter With Variable Reluctance Transducer

    NASA Astrophysics Data System (ADS)

    Gonzalez, Julio

    1987-01-01

    A new variable reluctance transducer is described. Two static coils constitute two branches of a Wheastone bridge. The magnetic circuit of each one of the windings is closed through two gear wheels attached to the shaft. These are related to each other in such a way as to leave two air gaps, each of these in front of one of the coils in the stator assambly. These gaps change with the torque.

  8. Toward effective needle steering in brain tissue.

    PubMed

    Engh, J A; Podnar, G; Kondziolka, D; Riviere, C N

    2006-01-01

    Recent research has exploited the inherent bending of a bevel-tipped needle during insertion, accomplishing steering of the needle by rotating the needle shaft. Combining this technique with the observation that a straight trajectory can be accomplished by spinning the needle at a constant rate during insertion, this paper presents a novel technique for proportional control of the curvature of the trajectory via duty-cycled spinning of the needle. In order to accommodate this technique to very soft tissues such as the brain, several custom needle prototypes have also been designed in order to increase the steering versatility of the system by maximizing the attainable curvature. The paper describes the needle-steering system and the needle prototypes, and presents preliminary results from tests in an artificial brain tissue substitute.

  9. Acoustic transducer for nuclear reactor monitoring

    DOEpatents

    Ahlgren, Frederic F.; Scott, Paul F.

    1977-01-01

    A transducer to monitor a parameter and produce an acoustic signal from which the monitored parameter can be recovered. The transducer comprises a modified Galton whistle which emits a narrow band acoustic signal having a frequency dependent upon the parameter being monitored, such as the temperature of the cooling media of a nuclear reactor. Multiple locations within a reactor are monitored simultaneously by a remote acoustic receiver by providing a plurality of transducers each designed so that the acoustic signal it emits has a frequency distinct from the frequencies of signals emitted by the other transducers, whereby each signal can be unambiguously related to a particular transducer.

  10. Thermal model for piezoelectric transducers (L).

    PubMed

    Butler, John L; Butler, Alexander L; Butler, Stephen C

    2012-10-01

    A lumped parameter equivalent circuit basis for calculating and allocating heat power sources in a transducer is presented along with experimental results. The simple model allows heat power calculations at resonance based on readily attainable parameters for transducers with uniform fields. Measured and finite element analysis of steady state thermal results are compared for the monopole mode of the single crystal driven modal transducer projector. The model serves as a physical and computational aid in the evaluation of piezoelectric transducer heating and may be used for evaluating highly coupled single crystal as well as ceramic piezoelectric transducers.

  11. Ultrasonic Transducer-Guided Electrochemical Impedance Spectroscopy to Assess Lipid-Laden Plaques.

    PubMed

    Ma, Jianguo; Luo, Yuan; Sevag Packard, René R; Ma, Teng; Ding, Yichen; Abiri, Parinaz; Tai, Yu-Chong; Zhou, Qifa; Shung, Kirk K; Li, Rongsong; Hsiai, Tzung

    2016-11-01

    Plaque rupture causes acute coronary syndromes and stroke. Intraplaque oxidized low density lipoprotein (oxLDL) is metabolically unstable and prone to induce rupture. We designed an intravascular ultrasound (IVUS)-guided electrochemical impedance spectroscopy (EIS) sensor to enhance the detection reproducibility of oxLDL-laden plaques. The flexible 2-point micro-electrode array for EIS was affixed to an inflatable balloon anchored onto a co-axial double layer catheter (outer diameter = 2 mm). The mechanically scanning-driven IVUS transducer (45 MHz) was deployed through the inner catheter (diameter = 1.3 mm) to the acoustic impedance matched-imaging window. Water filled the inner catheter to match acoustic impedance and air was pumped between the inner and outer catheters to inflate the balloon. The integrated EIS and IVUS sensor was deployed into the ex vivo aortas dissected from the fat-fed New Zealand White (NZW) rabbits (n=3 for fat-fed, n= 5 normal diet). IVUS imaging was able to guide the 2-point electrode to align with the plaque for EIS measurement upon balloon inflation. IVUS-guided EIS signal demonstrated reduced variability and increased reproducibility (p < 0.0001 for magnitude, p < 0.05 for phase at < 15 kHz) as compared to EIS sensor alone (p < 0.07 for impedance, p < 0.4 for phase at < 15 kHz). Thus, we enhanced topographic and EIS detection of oxLDL-laden plaques via a catheter-based integrated sensor design to enhance clinical assessment for unstable plaque.

  12. Characterizing tissue stiffness at the tip of a rigid needle using an opto-mechanical force sensor (Conference Presentation)

    NASA Astrophysics Data System (ADS)

    Beekmans, Steven V.; Iannuzzi, Davide; van den Dobbelsteen, John J.

    2016-03-01

    Each year, in the Netherlands alone, more than 50.000 percutaneous procedures are performed for treatment or for removal of tissue from possibly diseased organs, of which 30% return non-diagnostic due to erroneous needle targeting, often as a result of non-homogeneity of the penetrated tissue. In this study, we aim to facilitate needle targeting by assessing the tissue in front of the needle based on its mechanical properties. A probe that can identify tissues via real-time measurements of their mechanical properties is placed at the tip of the needle. The probe, actuated by a remote system at the distal part of the needle, employs the bending of a micro-machined cantilever fabricated on top of an optical fiber. The displacement of the cantilever, imposed by pressing a micro-bead (r = 75 µm) glued at the tip of the cantilever against the tissue, is interrogated by Fabry-Pérot interferometry and converted to force acted on the tissue in real-time. The force transducer is able to perform in harsh environments due to its monolithic design and all-optical working principle. Using our setup, load-indentation curves were obtained during needle insertion in several gelatin-based specimens. We demonstrate the ability of our device to detect and quantify layers of varying stiffness and to successfully locate tissue boundaries in animal tissue embedded in gelatin. Furthermore, a diagnostic measurement can be made by quantifying intra-organ tissue stiffness at the needle target location.

  13. Endoscopic Therapeutic Device Using Focused Ultrasonic Small Transducer

    NASA Astrophysics Data System (ADS)

    Yasui, Akihiro; Haga, Yoichi; Chen, Jiun-Jie; Iseki, Hiroshi; Esashi, Masayoshi; Wada, Hiroshi

    In this research, an ultrasonic probe (5.5 mm in diameter), which has a concave PZT transducer at its tip, was fabricated for ultrasonic treatments such as sonoporation and sonodynamic therapy in the human body using a catheter and/or endoscope. Ultrasound has the potential to enhance cytotoxicity of drugs such as porphyrins, a process referred to as sonodynamic therapy, and also to deliver macromolecules such as plasmid DNA, a process referred to as sonoporation. The fabricated probe was then experimentally characterized by measuring the acoustic intensity distribution around the focal point, using a PVDF needle-type ultrasonic hydrophone. When the PZT transducer was driven by a 120 Volts peak-to-peak AC signal at 1.83 MHz, the ultrasound output was successfully focused at the focal point, with a peak intensity of 24.9 W/cm2 (0.87 MPa). Using the fabricated probe, cultured Chinese Hamster Ovary (CHO) cells were exposed to ultrasound (1.83 MHz, continuous wave, peak acoustic pressure of 0.5 MPa) for 2 s in the presence of microbubbles MB-3 and Green Fluorescent Protein (GFP) plasmid DNA. As a result of sonication, the expression of GFP was observed in CHO cells.

  14. Biomechanics of a new atraumatic surgical needle holder.

    PubMed

    Towler, M A; Chen, N C; Moody, F P; McGregor, W; Thacker, J G; Rodeheaver, G T; Edlich, R F

    1991-01-01

    It is the purpose of this report to design, develop, and evaluate a needle holder whose jaws improve needle-holding security without altering the geometry of the curved surgical needle. The configuration of the jaws of this new needle holder is curved, conforming to the curvature of the surgical needle. A biomechanical study of this curved surgical needle holder demonstrates that it holds the curved needle securely without needle deformation.

  15. Characterization of dielectric electroactive polymer transducers

    NASA Astrophysics Data System (ADS)

    Nielsen, Dennis; Møller, Martin B.; Sarban, Rahimullah; Lassen, Benny; Knott, Arnold; Andersen, Michael A. E.

    2014-03-01

    Throughout this paper, a small-signal model of the Dielectric Electro Active Polymer (DEAP) transducer is analyzed. The DEAP transducer have been proposed as an alternative to the electrodynamic transducer in sound reproduction systems. In order to understand how the DEAP transducer works, and provide guidelines for design optimization, accurate characterization of the transducer must be established. A small signal model of the DEAP transducer is derived and its validity is investigated using impedance measurements. Impedance measurements are shown for a push-pull DEAP based loudspeaker, and the dependency of the biasing voltage is explained. A measuring setup is proposed, which allows the impedance to be measured, while the DEAP transducer is connected to its biasing source.

  16. A comparison of needle tip localization accuracy using 2D and 3D trans-rectal ultrasound for high-dose-rate prostate cancer brachytherapy treatment planning

    NASA Astrophysics Data System (ADS)

    Hrinivich, W. Thomas; Hoover, Douglas A.; Surry, Kathleen; Edirisinghe, Chandima; Montreuil, Jacques; D'Souza, David; Fenster, Aaron; Wong, Eugene

    2016-03-01

    Background: High-dose-rate brachytherapy (HDR-BT) is a prostate cancer treatment option involving the insertion of hollow needles into the gland through the perineum to deliver a radioactive source. Conventional needle imaging involves indexing a trans-rectal ultrasound (TRUS) probe in the superior/inferior (S/I) direction, using the axial transducer to produce an image set for organ segmentation. These images have limited resolution in the needle insertion direction (S/I), so the sagittal transducer is used to identify needle tips, requiring a manual registration with the axial view. This registration introduces a source of uncertainty in the final segmentations and subsequent treatment plan. Our lab has developed a device enabling 3D-TRUS guided insertions with high S/I spatial resolution, eliminating the need to align axial and sagittal views. Purpose: To compare HDR-BT needle tip localization accuracy between 2D and 3D-TRUS. Methods: 5 prostate cancer patients underwent conventional 2D TRUS guided HDR-BT, during which 3D images were also acquired for post-operative registration and segmentation. Needle end-length measurements were taken, providing a gold standard for insertion depths. Results: 73 needles were analyzed from all 5 patients. Needle tip position differences between imaging techniques was found to be largest in the S/I direction with mean+/-SD of -2.5+/-4.0 mm. End-length measurements indicated that 3D TRUS provided statistically significantly lower mean+/-SD insertion depth error of -0.2+/-3.4 mm versus 2.3+/-3.7 mm with 2D guidance (p < .001). Conclusions: 3D TRUS may provide more accurate HDR-BT needle localization than conventional 2D TRUS guidance for the majority of HDR-BT needles.

  17. In-plane ultrasonic needle tracking using a fiber-optic hydrophone

    SciTech Connect

    Xia, Wenfeng Desjardins, Adrien E.; Mari, Jean Martial; West, Simeon J.; Ginsberg, Yuval; David, Anna L.; Ourselin, Sebastien

    2015-10-15

    Purpose: Accurate and efficient guidance of needles to procedural targets is critically important during percutaneous interventional procedures. Ultrasound imaging is widely used for real-time image guidance in a variety of clinical contexts, but with this modality, uncertainties about the location of the needle tip within the image plane lead to significant complications. Whilst several methods have been proposed to improve the visibility of the needle, achieving accuracy and compatibility with current clinical practice is an ongoing challenge. In this paper, the authors present a method for directly visualizing the needle tip using an integrated fiber-optic ultrasound receiver in conjunction with the imaging probe used to acquire B-mode ultrasound images. Methods: Needle visualization and ultrasound imaging were performed with a clinical ultrasound imaging system. A miniature fiber-optic ultrasound hydrophone was integrated into a 20 gauge injection needle tip to receive transmissions from individual transducer elements of the ultrasound imaging probe. The received signals were reconstructed to create an image of the needle tip. Ultrasound B-mode imaging was interleaved with needle tip imaging. A first set of measurements was acquired in water and tissue ex vivo with a wide range of insertion angles (15°–68°) to study the accuracy and sensitivity of the tracking method. A second set was acquired in an in vivo swine model, with needle insertions to the brachial plexus. A third set was acquired in an in vivo ovine model for fetal interventions, with insertions to different locations within the uterine cavity. Two linear ultrasound imaging probes were used: a 14–5 MHz probe for the first and second sets, and a 9–4 MHz probe for the third. Results: During insertions in tissue ex vivo and in vivo, the imaged needle tip had submillimeter axial and lateral dimensions. The signal-to-noise (SNR) of the needle tip was found to depend on the insertion angle. With

  18. Electromechanical transduction in multilayer ionic transducers

    NASA Astrophysics Data System (ADS)

    Akle, Barbar; Leo, Donald J.

    2004-10-01

    A transducer consisting of multiple layers of ionic polymer material is developed for applications in sensing, actuation and control. A multilayer transducer is fabricated by layering individual transducers on top of one another. Each multilayer transducer consists of two to four individual layers each approximately 200 µm thick. The electrical characteristics of the transducers can be varied by connecting the layers in either a parallel arrangement or a series arrangement. The tradeoff in deflection and force is obtained by controlling the mechanical constraint at the interface. Packaging the transducer in an outer coating produces a hard constraint between layers and reduces the deflection with a force that increases linearly with the number of layers. This configuration also increases the bandwidth of the transducer. Removing the outer packaging produces an actuator that maintains the deflection of a single layer with an increased force output. This is obtained by allowing the layers to slide relative to one another during bending. Experiments on transducers with one to three layers are performed and the results are compared to an equivalent circuit model which was modified to accommodate multilayer transducers. The modification is performed on four different boundary conditions: two electrical, the series and the parallel connection, and two mechanical, the zero interfacial friction and the zero slip on the interface. Expressions for blocked force, free deflection, and electrical impedance of the transducer are developed in terms of fundamental material parameters, transducer geometry, and the number of individual layers. The trends in the transducer response are validated using experiments on transducers with multiple polymer layers.

  19. Shear wave transducer for boreholes

    DOEpatents

    Mao, N.H.

    1984-08-23

    A technique and apparatus is provided for estimating in situ stresses by measuring stress-induced velocity anisotropy around a borehole. Two sets each of radially and tangentially polarized transducers are placed inside the hole with displacement directions either parallel or perpendicular to the principal stress directions. With this configuration, relative travel times are measured by both a pulsed phase-locked loop technique and a cross correlation of digitized waveforms. The biaxial velocity data are used to back-calculate the applied stress.

  20. Solar cell angular position transducer

    NASA Technical Reports Server (NTRS)

    Sandford, M. C.; Gray, D. L. (Inventor)

    1980-01-01

    An angular position transducer utilizing photocells and a light source is disclosed. The device uses a fully rotatable baffle which is connected via an actuator shaft to the body whose rotational displacement is to be measured. The baffle blocks the light path between the light source and the photocells so that a constant semicircular beam of light reaches the photocells. The current produced by the photocells is fed through a resistor, a differential amplifier measures the voltage drop across the resistor which indicates the angular position of the actuator shaft and hence of the object.

  1. Compensating for Torsion Windup in Steerable Needles

    PubMed Central

    Reed, Kyle B.

    2010-01-01

    Long, flexible, bevel-tip needles curve during insertion into tissue, and rotations of the needle base reorient the tip to steer subsequent insertions. Friction between the tissue and the needle shaft, however, can cause a severe discrepancy between the needle base and tip angles. In this paper, I demonstrate an algorithm to properly align the entire length of the needle using torque measured at the base. My algorithm uses several intermediate base rotations to align the orientation of points along the shaft with the desired angle, with minimal remaining torque exerted by the base. I performed an experimental validation with four angle sensors attached to the needle throughout the tissue. My compensation algorithm decreased the lag throughout the needle by up to 88%. PMID:20640198

  2. Analog circuit for controlling acoustic transducer arrays

    DOEpatents

    Drumheller, Douglas S.

    1991-01-01

    A simplified ananlog circuit is presented for controlling electromechanical transducer pairs in an acoustic telemetry system. The analog circuit of this invention comprises a single electrical resistor which replaces all of the digital components in a known digital circuit. In accordance with this invention, a first transducer in a transducer pair of array is driven in series with the resistor. The voltage drop across this resistor is then amplified and used to drive the second transducer. The voltage drop across the resistor is proportional and in phase with the current to the transducer. This current is approximately 90 degrees out of phase with the driving voltage to the transducer. This phase shift replaces the digital delay required by the digital control circuit of the prior art.

  3. ERROR COMPENSATOR FOR A POSITION TRANSDUCER

    DOEpatents

    Fowler, A.H.

    1962-06-12

    A device is designed for eliminating the effect of leadscrew errors in positioning machines in which linear motion of a slide is effected from rotary motion of a leadscrew. This is accomplished by providing a corrector cam mounted on the slide, a cam follower, and a transducer housing rotatable by the follower to compensate for all the reproducible errors in the transducer signal which can be related to the slide position. The transducer has an inner part which is movable with respect to the transducer housing. The transducer inner part is coupled to the means for rotating the leadscrew such that relative movement between this part and its housing will provide an output signal proportional to the position of the slide. The corrector cam and its follower perform the compensation by changing the angular position of the transducer housing by an amount that is a function of the slide position and the error at that position. (AEC)

  4. Two-Element Transducer for Ultrasound

    NASA Technical Reports Server (NTRS)

    Lecroissette, D. H.; Heyser, R. C.

    1986-01-01

    Separation of transmitting and receiving units improves probing of deep tissue. Ultrasonic transducer has dual elements to increase depth at which sonic images are made of biological tissue. Transducer uses separate transmitting and receiving elements, and frequency response of receiving element independently designed to accommodate attenuation of higher frequencies by tissue. New transducer intended for pulse-echo ultrasonic systems in which reflected sound pulses reveal features in tissue.

  5. Method for Transducer Transient Suppression. I. Theory

    DTIC Science & Technology

    1992-09-01

    Vol. 92, No. 3, September 1992 Method for transducer transient suppression. I: Theory Jean C. Piquette Naval Research Laboratory. Underwater Sound...TITLE AND SUBTITLE 5. FUNDING NUMBERS Method for transducer transient suppression. I: Theo:y PE - 61153N TA - RROII-08-42 WU - DN220-161 6. AUTHOR(S) Jean...STATEMENT 12b. DISTRIBUTION CODE Approved for public release; distribution unlimited. 13. ABSTRACT (Maximum 200 words) The problem of driving a transducer in

  6. Finite Element Modeling for Ultrasonic Transducers (Preprint)

    DTIC Science & Technology

    1998-02-27

    virtual prototyping of transducers . Fig. 18 shows a 3D model of a Tonpilz device for low frequency sensing in air. This classical design is usually used...coupled Tonpilz transducer . A thick, flexible matching layer is bonded to the face of the conical head-mass. 7. CONCLUSIONS This paper was intended as a...This is a preprint of a paper published in Proc. SPIE Int. Symp. Medical Imaging 1998, San Diego, Feb 21-27, 1998 Ultrasonic Transducer Engineering

  7. Measurement methods of ultrasonic transducer sensitivity.

    PubMed

    Xiao, Dingguo; Fan, Qiong; Xu, Chunguang; Zhang, Xiuhua

    2016-05-01

    Sensitivity is an important parameter to describe the electro-acoustic energy conversion efficiency of ultrasonic transducer. In this paper, the definition of sensitivity and reciprocity of ultrasonic transducer is studied. The frequency response function of a transducer is the spectrum of its sensitivity, which reflects the response sensitivity of the transducer for input signals at different frequencies. Four common methods which are used to measure the disc-vibrator transducer sensitivity are discussed in current investigation. The reciprocity method and the pulse-echo method are based on the reciprocity of the transducer. In the laser vibrometer method measurement, the normal velocity on the transducer radiating surface is directly measured by a laser vibrometer. In the measurement process of the hydrophone method, a calibrated hydrophone is used to measure the transmitted field. The validity of these methods is checked by experimental test. All of the four methods described are sufficiently accurate for transducer sensitivity measurement, while each method has its advantages and limitations. In practical applications, the appropriate method to measure transducer sensitivity should be selected based on actual conditions.

  8. Estimation of Model Parameters for Steerable Needles

    PubMed Central

    Park, Wooram; Reed, Kyle B.; Okamura, Allison M.; Chirikjian, Gregory S.

    2010-01-01

    Flexible needles with bevel tips are being developed as useful tools for minimally invasive surgery and percutaneous therapy. When such a needle is inserted into soft tissue, it bends due to the asymmetric geometry of the bevel tip. This insertion with bending is not completely repeatable. We characterize the deviations in needle tip pose (position and orientation) by performing repeated needle insertions into artificial tissue. The base of the needle is pushed at a constant speed without rotating, and the covariance of the distribution of the needle tip pose is computed from experimental data. We develop the closed-form equations to describe how the covariance varies with different model parameters. We estimate the model parameters by matching the closed-form covariance and the experimentally obtained covariance. In this work, we use a needle model modified from a previously developed model with two noise parameters. The modified needle model uses three noise parameters to better capture the stochastic behavior of the needle insertion. The modified needle model provides an improvement of the covariance error from 26.1% to 6.55%. PMID:21643451

  9. Standards for dielectric elastomer transducers

    NASA Astrophysics Data System (ADS)

    Carpi, Federico; Anderson, Iain; Bauer, Siegfried; Frediani, Gabriele; Gallone, Giuseppe; Gei, Massimiliano; Graaf, Christian; Jean-Mistral, Claire; Kaal, William; Kofod, Guggi; Kollosche, Matthias; Kornbluh, Roy; Lassen, Benny; Matysek, Marc; Michel, Silvain; Nowak, Stephan; O'Brien, Benjamin; Pei, Qibing; Pelrine, Ron; Rechenbach, Björn; Rosset, Samuel; Shea, Herbert

    2015-10-01

    Dielectric elastomer transducers consist of thin electrically insulating elastomeric membranes coated on both sides with compliant electrodes. They are a promising electromechanically active polymer technology that may be used for actuators, strain sensors, and electrical generators that harvest mechanical energy. The rapid development of this field calls for the first standards, collecting guidelines on how to assess and compare the performance of materials and devices. This paper addresses this need, presenting standardized methods for material characterisation, device testing and performance measurement. These proposed standards are intended to have a general scope and a broad applicability to different material types and device configurations. Nevertheless, they also intentionally exclude some aspects where knowledge and/or consensus in the literature were deemed to be insufficient. This is a sign of a young and vital field, whose research development is expected to benefit from this effort towards standardisation.

  10. Dimensions of stabident intraosseous perforators and needles.

    PubMed

    Ramlee, R A; Whitworth, J

    2001-09-01

    Problems can be encountered inserting intraosseous injection needles through perforation sites. This in vitro study examined the variability and size compatibility of Stabident intraosseous injection components. The diameters of 40 needles and perforators from a single Stabident kit were measured in triplicate with a toolmakers microscope. One-way ANOVA revealed that mean needle diameter (0.411 mm) was significantly narrower than mean perforator diameter (0.427 mm) (p < 0.001). A frequency distribution plot revealed that needle diameter followed a normal distribution, indicating tight quality control during manufacture. The diameter of perforators was haphazardly distributed, with a clustering of 15% at the lower limit of the size range. However on no occasion was the diameter of a perforator smaller than that of an injection needle. We conclude that components of the Stabident intraosseous anaesthetic system are size-compatible, but there is greater and more haphazard variability in the diameter of perforators than injection needles.

  11. 21 CFR 870.2880 - Ultrasonic transducer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... structures. This device includes phased arrays and two-dimensional scanning transducers. (b) Classification... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Ultrasonic transducer. 870.2880 Section 870.2880...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2880 Ultrasonic...

  12. 21 CFR 870.2880 - Ultrasonic transducer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... structures. This device includes phased arrays and two-dimensional scanning transducers. (b) Classification... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Ultrasonic transducer. 870.2880 Section 870.2880...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2880 Ultrasonic...

  13. 21 CFR 870.2880 - Ultrasonic transducer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... structures. This device includes phased arrays and two-dimensional scanning transducers. (b) Classification... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Ultrasonic transducer. 870.2880 Section 870.2880...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2880 Ultrasonic...

  14. Opto-acoustic transducer for medical applications

    DOEpatents

    Benett, William; Celliers, Peter; Da Silva, Luiz; Glinsky, Michael; London, Richard; Maitland, Duncan; Matthews, Dennis; Krulevich, Peter; Lee, Abraham

    2002-01-01

    This invention is an optically activated transducer for generating acoustic vibrations in a biological medium. The transducer is located at the end of a fiber optic which may be located within a catheter. Energy for operating the transducer is provided optically by laser light transmitted through the fiber optic to the transducer. Pulsed laser light is absorbed in the working fluid of the transducer to generate a thermal pressure and consequent adiabatic expansion of the transducer head such that it does work against the ambient medium. The transducer returns to its original state by a process of thermal cooling. The motion of the transducer within the ambient medium couples acoustic energy into the medium. By pulsing the laser at a high repetition rate (which may vary from CW to 100 kHz) an ultrasonic radiation field can be established locally in the medium. This method of producing ultrasonic vibrations can be used in vivo for the treatment of stroke-related conditions in humans, particularly for dissolving thrombus. The catheter may also incorporate anti-thrombolytic drug treatments as an adjunct therapy and it may be operated in conjunction with ultrasonic detection equipment for imaging and feedback control.

  15. Opto-acoustic transducer for medical applications

    DOEpatents

    Benett, W.; Celliers, P.; Da Silva, L.; Glinsky, M.; London, R.; Maitland, D.; Matthews, D.; Krulevich, P.; Lee, A.

    1999-08-31

    This invention is an optically activated transducer for generating acoustic vibrations in a biological medium. The transducer is located at the end of a fiber optic which may be located within a catheter. Energy for operating the transducer is provided optically by laser light transmitted through the fiber optic to the transducer. Pulsed laser light is absorbed in the working fluid of the transducer to generate a thermal pressure and consequent adiabatic expansion of the transducer head such that it does work against the ambient medium. The transducer returns to its original state by a process of thermal cooling. The motion of the transducer within the ambient medium couples acoustic energy into the medium. By pulsing the laser at a high repetition rate (which may vary from CW to 100 kHz) an ultrasonic radiation field can be established locally in the medium. This method of producing ultrasonic vibrations can be used in vivo for the treatment of stroke-related conditions in humans, particularly for dissolving thrombus. The catheter may also incorporate anti-thrombolytic drug treatments as an adjunct therapy and it may be operated in conjunction with ultrasonic detection equipment for imaging and feedback control. 7 figs.

  16. Opto-acoustic transducer for medical applications

    DOEpatents

    Benett, William; Celliers, Peter; Da Silva, Luiz; Glinsky, Michael; London, Richard; Maitland, Duncan; Matthews, Dennis; Krulevich, Peter; Lee, Abraham

    1999-01-01

    This invention is an optically activated transducer for generating acoustic vibrations in a biological medium. The transducer is located at the end of a fiber optic which may be located within a catheter. Energy for operating the transducer is provided optically by laser light transmitted through the fiber optic to the transducer. Pulsed laser light is absorbed in the working fluid of the transducer to generate a thermal pressure and consequent adiabatic expansion of the transducer head such that it does work against the ambient medium. The transducer returns to its original state by a process of thermal cooling. The motion of the transducer within the ambient medium couples acoustic energy into the medium. By pulsing the laser at a high repetition rate (which may vary from CW to 100 kHz) an ultrasonic radiation field can be established locally in the medium. This method of producing ultrasonic vibrations can be used in vivo for the treatment of stroke-related conditions in humans, particularly for dissolving thrombus. The catheter may also incorporate anti-thrombolytic drug treatments as an adjunct therapy and it may be operated in conjunction with ultrasonic detection equipment for imaging and feedback control.

  17. Piezoelectric materials used in underwater acoustic transducers

    SciTech Connect

    Li, Huidong; Deng, Zhiqun; Carlson, Thomas J.

    2012-07-07

    Piezoelectric materials have been used in underwater acoustic transducers for nearly a century. In this paper, we reviewed four different types of piezoelectric materials: piezoelectric ceramics, single crystals, composites, and polymers, which are widely used in underwater acoustic transducers nowadays. Piezoelectric ceramics are the most dominant material type and are used as a single-phase material or one of the end members in composites. Piezoelectric single crystals offer outstanding electromechanical response but are limited by their manufacturing cost. Piezoelectric polymers provide excellent acoustic impedance matching and transducer fabrication flexibility although their piezoelectric properties are not as good as ceramics and single crystals. Composites combined the merits of ceramics and polymers and are receiving increased attention. The typical structure and electromechanical properties of each type of materials are introduced and discussed with respect to underwater acoustic transducer applications. Their advantages and disadvantages are summarized. Some of the critical design considerations when developing underwater acoustic transducers with these materials are also touched upon.

  18. Thermodynamic Pressure/Temperature Transducer Health Check

    NASA Technical Reports Server (NTRS)

    Immer, Christopher D. (Inventor); Eckhoff, Anthony (Inventor); Medelius, Pedro J. (Inventor); Deyoe, Richard T. (Inventor); Starr, Stanley O. (Inventor)

    2004-01-01

    A device and procedure for checking the health of a pressure transducer in situ is provided. The procedure includes measuring a fixed change in pressure above ambient pressure and a fixed change in pressure below ambient pressure. This is done by first sealing an enclosed volume around the transducer with a valve. A piston inside the sealed volume is increasing the pressure. A fixed pressure below ambient pressure is obtained by opening the valve, driving the piston The output of the pressure transducer is recorded for both the overpressuring and the underpressuring. By comparing this data with data taken during a preoperative calibration, the health of the transducer is determined from the linearity, the hysteresis, and the repeatability of its output. The further addition of a thermometer allows constant offset error in the transducer output to be determined.

  19. Observations of Needle-Tissue Interactions

    PubMed Central

    Misra, Sarthak; Reed, Kyle B.; Ramesh, K. T.; Okamura, Allison M.

    2010-01-01

    Needles with asymmetric bevel tips naturally bend when they are inserted into soft tissue. In this study, we present an analytical model for the loads developed at the bevel tip during needle-tissue interaction. The model calculates the loads based on the geometry of the bevel edge and gel material properties. The modeled transverse force developed at the tip is compared to forces measured experimentally. The analytical model explains the trends observed in the experiments. In addition to macroscopic studies, we also present microscopic observations of needle-tissue interactions. These results contribute to a mechanics-based model of robotic needle steering, extending previous work on kinematic models. PMID:19963709

  20. Metallurgically bonded needle holder jaws. A technique to enhance needle holding security without sutural damage.

    PubMed

    Abidin, M R; Dunlapp, J A; Towler, M A; Becker, D G; Thacker, J G; McGregor, W; Edlich, R F

    1990-10-01

    A new needle holder jaw face has been specifically designed and developed to increase needle holding security without sutural damage. Tungsten carbide particles have been metallurgically bonded into the stainless steel jaw to create a fine granular surface. This bonded jaw enhances needle holding security by limiting either twisting or rotation of the clamped needle. In addition, compression of the monofilament synthetic sutures by the bonded jaws does not reduce suture breaking strength.

  1. Using Portable Transducers to Measure Tremor Severity

    PubMed Central

    Elble, Rodger J.; McNames, James

    2016-01-01

    Background Portable motion transducers, suitable for measuring tremor, are now available at a reasonable cost. The use of these transducers requires knowledge of their limitations and data analysis. The purpose of this review is to provide a practical overview and example software for using portable motion transducers in the quantification of tremor. Methods Medline was searched via PubMed.gov in December 2015 using the Boolean expression “tremor AND (accelerometer OR accelerometry OR gyroscope OR inertial measurement unit OR digitizing tablet OR transducer).” Abstracts of 419 papers dating back to 1964 were reviewed for relevant portable transducers and methods of tremor analysis, and 105 papers written in English were reviewed in detail. Results Accelerometers, gyroscopes, and digitizing tablets are used most commonly, but few are sold for the purpose of measuring tremor. Consequently, most software for tremor analysis is developed by the user. Wearable transducers are capable of recording tremor continuously, in the absence of a clinician. Tremor amplitude, frequency, and occurrence (percentage of time with tremor) can be computed. Tremor amplitude and occurrence correlate strongly with clinical ratings of tremor severity. Discussion Transducers provide measurements of tremor amplitude that are objective, precise, and valid, but the precision and accuracy of transducers are mitigated by natural variability in tremor amplitude. This variability is so great that the minimum detectable change in amplitude, exceeding random variability, is comparable for scales and transducers. Research is needed to determine the feasibility of detecting smaller change using averaged data from continuous long-term recordings with wearable transducers. PMID:27257514

  2. [Pulmonary needle biopsy in children].

    PubMed

    Gerbeaux, J

    1975-01-01

    Pulmonary biopsy done with a needle of circular bore, can be performed on very young children. A sample of tissue, big enough to establish a precise diagnosis in 2/3 of cases, can be obtained. The main complication is pneumothorax occuring about once in five. Hemoptysia or hemorrhage has never been observed. A proposed indication of premortem biopsy accelerated the death of a child with congenital pulmonary fibrosis. The search of a diagnosis in diffuse pulmonary diseases is the major indication for pulmonary biopsy in the child.

  3. Ultrasound-guided three-dimensional needle steering in biological tissue with curved surfaces.

    PubMed

    Abayazid, Momen; Moreira, Pedro; Shahriari, Navid; Patil, Sachin; Alterovitz, Ron; Misra, Sarthak

    2015-01-01

    In this paper, we present a system capable of automatically steering a bevel-tipped flexible needle under ultrasound guidance toward a physical target while avoiding a physical obstacle embedded in gelatin phantoms and biological tissue with curved surfaces. An ultrasound pre-operative scan is performed for three-dimensional (3D) target localization and shape reconstruction. A controller based on implicit force control is developed to align the transducer with curved surfaces to assure the maximum contact area, and thus obtain an image of sufficient quality. We experimentally investigate the effect of needle insertion system parameters such as insertion speed, needle diameter and bevel angle on target motion to adjust the parameters that minimize the target motion during insertion. A fast sampling-based path planner is used to compute and periodically update a feasible path to the target that avoids obstacles. We present experimental results for target reconstruction and needle insertion procedures in gelatin-based phantoms and biological tissue. Mean targeting errors of 1.46±0.37 mm, 1.29±0.29 mm and 1.82±0.58 mm are obtained for phantoms with inclined, curved and combined (inclined and curved) surfaces, respectively, for insertion distance of 86-103 mm. The achieved targeting errors suggest that our approach is sufficient for targeting lesions of 3mm radius that can be detected using clinical ultrasound imaging systems.

  4. Ultrasound-guided three-dimensional needle steering in biological tissue with curved surfaces

    PubMed Central

    Abayazid, Momen; Moreira, Pedro; Shahriari, Navid; Patil, Sachin; Alterovitz, Ron; Misra, Sarthak

    2015-01-01

    In this paper, we present a system capable of automatically steering a bevel-tipped flexible needle under ultrasound guidance toward a physical target while avoiding a physical obstacle embedded in gelatin phantoms and biological tissue with curved surfaces. An ultrasound pre-operative scan is performed for three-dimensional (3D) target localization and shape reconstruction. A controller based on implicit force control is developed to align the transducer with curved surfaces to assure the maximum contact area, and thus obtain an image of sufficient quality. We experimentally investigate the effect of needle insertion system parameters such as insertion speed, needle diameter and bevel angle on target motion to adjust the parameters that minimize the target motion during insertion. A fast sampling-based path planner is used to compute and periodically update a feasible path to the target that avoids obstacles. We present experimental results for target reconstruction and needle insertion procedures in gelatin-based phantoms and biological tissue. Mean targeting errors of 1.46 ± 0.37 mm, 1.29 ± 0.29 mm and 1.82 ± 0.58 mm are obtained for phantoms with inclined, curved and combined (inclined and curved) surfaces, respectively, for insertion distance of 86–103 mm. The achieved targeting errors suggest that our approach is sufficient for targeting lesions of 3 mm radius that can be detected using clinical ultrasound imaging systems. PMID:25455165

  5. Geographical and climatic limits of needle types of one- and two-needled pinyon pines

    PubMed Central

    Cole, Kenneth L; Fisher, Jessica; Arundel, Samantha T; Cannella, John; Swift, Sandra

    2008-01-01

    Aim The geographical extent and climatic tolerances of one- and two-needled pinyon pines (Pinus subsect. Cembroides) are the focus of questions in taxonomy, palaeoclimatology and modelling of future distributions. The identification of these pines, traditionally classified by one- versus two-needled fascicles, is complicated by populations with both one- and two-needled fascicles on the same tree, and the description of two more recently described one-needled varieties: the fallax-type and californiarum-type. Because previous studies have suggested correlations between needle anatomy and climate, including anatomical plasticity reflecting annual precipitation, we approached this study at the level of the anatomy of individual pine needles rather than species. Location Western North America. Methods We synthesized available and new data from field and herbarium collections of needles to compile maps of their current distributions across western North America. Annual frequencies of needle types were compared with local precipitation histories for some stands. Historical North American climates were modelled on a c. 1-km grid using monthly temperature and precipitation values. A geospatial model (ClimLim), which analyses the effect of climate-modulated physiological and ecosystem processes, was used to rank the importance of seasonal climate variables in limiting the distributions of anatomical needle types. Results The pinyon needles were classified into four distinct types based upon the number of needles per fascicle, needle thickness and the number of stomatal rows and resin canals. The individual needles fit well into four categories of needle types, whereas some trees exhibit a mixture of two needle types. Trees from central Arizona containing a mixture of Pinus edulis and fallax-type needles increased their percentage of fallax-type needles following dry years. All four needle types occupy broader geographical regions with distinctive precipitation regimes

  6. Geographical and climatic limits of needle types of one- and two-needled pinyon pines.

    PubMed

    Cole, Kenneth L; Fisher, Jessica; Arundel, Samantha T; Cannella, John; Swift, Sandra

    2008-02-01

    AIM: The geographical extent and climatic tolerances of one- and two-needled pinyon pines (Pinus subsect. Cembroides) are the focus of questions in taxonomy, palaeoclimatology and modelling of future distributions. The identification of these pines, traditionally classified by one- versus two-needled fascicles, is complicated by populations with both one- and two-needled fascicles on the same tree, and the description of two more recently described one-needled varieties: the fallax-type and californiarum-type. Because previous studies have suggested correlations between needle anatomy and climate, including anatomical plasticity reflecting annual precipitation, we approached this study at the level of the anatomy of individual pine needles rather than species. LOCATION: Western North America. METHODS: We synthesized available and new data from field and herbarium collections of needles to compile maps of their current distributions across western North America. Annual frequencies of needle types were compared with local precipitation histories for some stands. Historical North American climates were modelled on a c. 1-km grid using monthly temperature and precipitation values. A geospatial model (ClimLim), which analyses the effect of climate-modulated physiological and ecosystem processes, was used to rank the importance of seasonal climate variables in limiting the distributions of anatomical needle types. RESULTS: The pinyon needles were classified into four distinct types based upon the number of needles per fascicle, needle thickness and the number of stomatal rows and resin canals. The individual needles fit well into four categories of needle types, whereas some trees exhibit a mixture of two needle types. Trees from central Arizona containing a mixture of Pinus edulis and fallax-type needles increased their percentage of fallax-type needles following dry years. All four needle types occupy broader geographical regions with distinctive precipitation regimes

  7. Geographical and climatic limits of needle types of one- and two-needled pinyon pines

    USGS Publications Warehouse

    Cole, K.L.; Fisher, J.; Arundel, S.T.; Cannella, J.; Swift, S.

    2008-01-01

    Aim: The geographical extent and climatic tolerances of one- and two-needled pinyon pines (Pinus subsect. Cembroides) are the focus of questions in taxonomy, palaeoclimatology and modelling of future distributions. The identification of these pines, traditionally classified by one- versus two-needled fascicles, is complicated by populations with both one- and two-needled fascicles on the same tree, and the description of two more recently described one-needled varieties: the fallax-type and californiarum-type. Because previous studies have suggested correlations between needle anatomy and climate, including anatomical plasticity reflecting annual precipitation, we approached this study at the level of the anatomy of individual pine needles rather than species. Location: Western North America. Methods: We synthesized available and new data from field and herbarium collections of needles to compile maps of their current distributions across western North America. Annual frequencies of needle types were compared with local precipitation histories for some stands. Historical North American climates were modelled on a c. 1-km grid using monthly temperature and precipitation values. A geospatial model (ClimLim), which analyses the effect of climate-modulated physiological and ecosystem processes, was used to rank the importance of seasonal climate variables in limiting the distributions of anatomical needle types. Results: The pinyon needles were classified into four distinct types based upon the number of needles per fascicle, needle thickness and the number of stomatal rows and resin canals. The individual needles fit well into four categories of needle types, whereas some trees exhibit a mixture of two needle types. Trees from central Arizona containing a mixture of Pinus edulis and fallax-type needles increased their percentage of fallax-type needles following dry years. All four needle types occupy broader geographical regions with distinctive precipitation regimes

  8. Characterization of needle-assisted jet injections.

    PubMed

    Li, Xinxin; Ruddy, Bryan; Taberner, Andrew

    2016-12-10

    Hypodermic injections have been the standard for transcutaneous drug delivery for many years. However, needle phobia, pain, and risks of needle-stick injuries have manifested in poor patient compliance. Needle-free jet injections (NFJI) have been developed to address these drawbacks but the reliability of dose and depth of delivery have been limited by a lack of control over jet parameters, and by variability in the skin's mechanical properties among individuals. Moreover, the device size and cost have been restrained by the high pressure (>20MPa) required to penetrate the skin. Needle-assisted jet injections have been proposed to improve delivery reliability of conventional jet injectors by penetrating the skin with a short needle (<5mm) and thereby allowing jet delivery to a desired injection depth at a reduced pressure. This study characterized needle-assisted jet injections performed after first penetrating the skin with a 1.5mm needle, examining the effect of needle size on jet parameters, and evaluating injection performance in porcine skin. A voice-coil actuated jet injector was modified to incorporate needles of 30G, 31G and 32G. A series of pulse tests was performed to compare jet velocity and injection volume across the needle sizes, where it was found that the jet velocity and injection volume achieved with 32G needles were 13% and 16% lower, respectively, than with 30G. In contrast, there was no significant difference in jet velocity and injection volume between 30G and 31G needles, suggesting that a reduction of 10μm in the mean inner diameter of the 31G needle has minimal impact on jet velocity and injection volume. Injection studies performed in porcine skin revealed that injections driven by fluid pressures ranging between 0.8MPa and 1.4MPa were able to achieve substantial injectate penetration (~10mm) and delivery (~100μL) into subcutaneous fat regardless of needle size, in a period of 40ms. The required pressures are an order of magnitude lower

  9. Ultrasound-Guided Fine Needle Aspiration Biopsy of the Thyroid

    MedlinePlus

    ... Index A-Z Ultrasound-Guided Fine Needle Aspiration Biopsy of the Thyroid An ultrasound-guided thyroid biopsy ... Thyroid? What is Ultrasound-Guided Fine Needle Aspiration Biopsy of the Thyroid? During a fine needle aspiration ...

  10. The trapped fluid transducer: modeling and optimization.

    PubMed

    Cheng, Lei; Grosh, Karl

    2008-06-01

    Exact and approximate formulas for calculating the sensitivity and bandwidth of an electroacoustic transducer with an enclosed or trapped fluid volume are developed. The transducer is composed of a fluid-filled rectangular duct with a tapered-width plate on one wall emulating the biological basilar membrane in the cochlea. A three-dimensional coupled fluid-structure model is developed to calculate the transducer sensitivity by using a boundary integral method. The model is used as the basis of an optimization methodology seeking to enhance the transducer performance. Simplified formulas are derived from the model to estimate the transducer sensitivity and the fundamental resonant frequency with good accuracy and much less computational cost. By using the simplified formulas, one can easily design the geometry of the transducer to achieve the optimal performance. As an example design, the transducer achieves a sensitivity of around -200 dB (1 VmuPa) at 10 kHz frequency range with piezoelectric sensing. In analogy to the cochlea, a tapered-width plate design is considered and shown to have a more uniform frequency response than a similar plate with no taper.

  11. Modeling of functionally graded piezoelectric ultrasonic transducers.

    PubMed

    Rubio, Wilfredo Montealegre; Buiochi, Flávio; Adamowski, Julio Cezar; Silva, Emílio Carlos Nelli

    2009-05-01

    The application of functionally graded material (FGM) concept to piezoelectric transducers allows the design of composite transducers without interfaces, due to the continuous change of property values. Thus, large improvements can be achieved, as reduction of stress concentration, increasing of bonding strength, and bandwidth. This work proposes to design and to model FGM piezoelectric transducers and to compare their performance with non-FGM ones. Analytical and finite element (FE) modeling of FGM piezoelectric transducers radiating a plane pressure wave in fluid medium are developed and their results are compared. The ANSYS software is used for the FE modeling. The analytical model is based on FGM-equivalent acoustic transmission-line model, which is implemented using MATLAB software. Two cases are considered: (i) the transducer emits a pressure wave in water and it is composed of a graded piezoceramic disk, and backing and matching layers made of homogeneous materials; (ii) the transducer has no backing and matching layer; in this case, no external load is simulated. Time and frequency pressure responses are obtained through a transient analysis. The material properties are graded along thickness direction. Linear and exponential gradation functions are implemented to illustrate the influence of gradation on the transducer pressure response, electrical impedance, and resonance frequencies.

  12. Estimating needle-tissue interaction forces for hollow needles using fiber Bragg grating sensors

    NASA Astrophysics Data System (ADS)

    Kumar, Saurabh; Shrikanth, V.; Bharadwaj, Amrutur; Asokan, Sundarrajan; Bobji, M. S.

    2016-03-01

    Brachytherapy and neurological procedures can benefit from real-time estimation of needle-tissue interaction forces, specifically for robotic or robot-assisted procedures. Fiber Bragg Grating Sensors provide advantages of very small size and electromagnetic immunity for use in measurement of the forces directly at the needle tip. This has advantages compared to measurements at the needle shaft which require extensive models of the friction between needle and tissues with varying depth. This paper presents the measurement of tip forces for a hollow needle and compensation for bending when encountering regions of varying stiffness in phantoms with multiple layers prepared using Polydimethylsiloxane.

  13. Seismic transducer modeling using ABAQUS

    SciTech Connect

    Stephen R. Novascone

    2004-05-01

    A seismic transducer, known as an orbital vibrator, consists of a rotating imbalance driven by an electric motor. When suspended in a liquid-filled wellbore, vibrations of the device are coupled to the surrounding geologic media. In this mode, an orbital vibrator can be used as an efficient rotating dipole source for seismic imaging. Alternately, the motion of an orbital vibrator is affected by the physical properties of the surrounding media. From this point of view, an orbital vibrator can be used as a stand-alone sensor. The reaction to the surroundings can be sensed and recorded by geophones inside the orbital vibrator. These reactions are a function of the media’s physical properties such as modulus, damping, and density, thereby identifying the rock type. This presentation shows how the orbital vibrator and surroundings were modeled with an ABAQUS acoustic FEM. The FEM is found to compare favorably with theoretical predictions. A 2D FEM and analytical model are compared to an experimental data set. Each model compares favorably with the data set.

  14. [Academic origin of round magnetic needle and standardization operation].

    PubMed

    Cheng, Yan-Ting; Zhang, Tian-Sheng; Meng, Li-Qiang; Shi, Rui-Qi; Ji, Lai-Xi

    2014-07-01

    The origin and development of round magnetic needle was explored, and the structure of round magnetic needle was introduced in detail, including the handle, the body and the tip of the needle. The clinical opera tion of round magnetic needle were standardized from the aspects of the methods of holding needle, manipulation skill, tapping position, strength of manipulation, application scope and matters needing attention, which laid foundation for the popularization and application of round magnetic needle.

  15. 21 CFR 882.1350 - Needle electrode.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Needle electrode. 882.1350 Section 882.1350 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1350 Needle electrode....

  16. 21 CFR 882.1350 - Needle electrode.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Needle electrode. 882.1350 Section 882.1350 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1350 Needle electrode....

  17. 21 CFR 882.1350 - Needle electrode.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Needle electrode. 882.1350 Section 882.1350 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1350 Needle electrode....

  18. 21 CFR 882.1350 - Needle electrode.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Needle electrode. 882.1350 Section 882.1350 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1350 Needle electrode....

  19. 21 CFR 882.1350 - Needle electrode.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Needle electrode. 882.1350 Section 882.1350 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES NEUROLOGICAL DEVICES Neurological Diagnostic Devices § 882.1350 Needle electrode....

  20. Needle Exchange Programs and Drug Injection Behavior

    ERIC Educational Resources Information Center

    DeSimone, Jeff

    2005-01-01

    This study examines how drug injection and needle sharing propensities respond when a needle exchange program (NEP) is introduced into a city. I analyze 1989-1995 Drug Use Forecasting data on adult male arrestees from 24 large U.S. cities, in nine of which NEPs opened during the sample period. After controlling for cocaine and heroin prices, AIDS…

  1. A Miniaturized Class IV Flextensional Ultrasonic Transducer

    NASA Astrophysics Data System (ADS)

    Feeney, Andrew; Tweedie, Andrew; Mathieson, Andrew; Lucas, Margaret

    The class V transducer has found popularity in a diverse range of applications such as surgical and underwater projection systems, where high vibration amplitude for relatively low piezoceramic volume is generated. The class IV transducer offers the potential to attain even higher performance per volume than the class V. In this research, a miniaturized class IV power ultrasonic flextensional transducer is proposed. Simulations were performed using PZFlex finite element analysis, and electrical impedance analysis and experimental modal analysis were conducted for validation, where a high correlation between simulation and experiment has been demonstrated.

  2. Hybrid piezoelectric energy harvesting transducer system

    NASA Technical Reports Server (NTRS)

    Xu, Tian-Bing (Inventor); Jiang, Xiaoning (Inventor); Su, Ji (Inventor); Rehrig, Paul W. (Inventor); Hackenberger, Wesley S. (Inventor)

    2008-01-01

    A hybrid piezoelectric energy harvesting transducer system includes: (a) first and second symmetric, pre-curved piezoelectric elements mounted separately on a frame so that their concave major surfaces are positioned opposite to each other; and (b) a linear piezoelectric element mounted separately on the frame and positioned between the pre-curved piezoelectric elements. The pre-curved piezoelectric elements and the linear piezoelectric element are spaced from one another and communicate with energy harvesting circuitry having contact points on the frame. The hybrid piezoelectric energy harvesting transducer system has a higher electromechanical energy conversion efficiency than any known piezoelectric transducer.

  3. Fiber-Optic Fabry-Pérot Interferometers for Axial Force Sensing on the Tip of a Needle

    PubMed Central

    Beekmans, Steven; Lembrechts, Thomas; van den Dobbelsteen, John; van Gerwen, Dennis

    2016-01-01

    A range of complex percutaneous procedures, such as biopsy or regional anesthesia, rely heavily on accurate needle insertion. Small variations in the mechanical properties of the pierced tissue can however cause deviations from the projected needle path and can thus result in inaccurate placement of the needle. Navigation of a rigid needle towards the target tissue is traditionally based on the surgeons capacity to interpret small variations in the needle insertion force. A more accurate measurement of these small force variations enables improvement in needle targeting, can potentially aid in enhancing force feedback in robotic needle placement and can provide valuable information on tissue-tool interaction. In this study we investigated several concepts for the design of a force sensor based on a fiber-optic Fabry-Pérot interferometer to measure needle-tissue interaction forces on the tip of a 18 G needle, where special attention was given to concepts for a sensor with (1), an intrinsic low cross-sensitivity to temperature and (2), elementary design and fabrication. Three concepts, using either a quartz capillary, an Invar capillary or a thin polyimide film as the force sensitive element were prototyped and subjected to both static and dynamic testing. The force transducer based on a quartz capillary presented the lowest cross-sensitivity to temperature (12 mN/∘C) and good accuracy (maximum measurement error of 65 mN/10 N) in a measurement of static forces. However, limited strength of the sensor is expected to prevent usage of the quartz capillary in small diameter needles. The concepts for a sensor based on an Invar capillary or a thin polyimide film proved a higher cross-sensitivity to temperature (50 mN/∘C and 220 mN/∘C, respectively) and higher maximum measurement error (350 mN/10 N, 800 mN/10 N), comparable to those of FBG-based sensors reported in literature, but are likely to be more suitable for integration in very small biopsy needles. PMID

  4. Fiber-Optic Fabry-Pérot Interferometers for Axial Force Sensing on the Tip of a Needle.

    PubMed

    Beekmans, Steven; Lembrechts, Thomas; van den Dobbelsteen, John; van Gerwen, Dennis

    2016-12-26

    A range of complex percutaneous procedures, such as biopsy or regional anesthesia, rely heavily on accurate needle insertion. Small variations in the mechanical properties of the pierced tissue can however cause deviations from the projected needle path and can thus result in inaccurate placement of the needle. Navigation of a rigid needle towards the target tissue is traditionally based on the surgeons capacity to interpret small variations in the needle insertion force. A more accurate measurement of these small force variations enables improvement in needle targeting, can potentially aid in enhancing force feedback in robotic needle placement and can provide valuable information on tissue-tool interaction. In this study we investigated several concepts for the design of a force sensor based on a fiber-optic Fabry-Pérot interferometer to measure needle-tissue interaction forces on the tip of a 18 G needle, where special attention was given to concepts for a sensor with (1), an intrinsic low cross-sensitivity to temperature and (2), elementary design and fabrication. Three concepts, using either a quartz capillary, an Invar capillary or a thin polyimide film as the force sensitive element were prototyped and subjected to both static and dynamic testing. The force transducer based on a quartz capillary presented the lowest cross-sensitivity to temperature ( 12 m N / ∘ C) and good accuracy (maximum measurement error of 65 m N /10 N ) in a measurement of static forces. However, limited strength of the sensor is expected to prevent usage of the quartz capillary in small diameter needles. The concepts for a sensor based on an Invar capillary or a thin polyimide film proved a higher cross-sensitivity to temperature ( 50 m N / ∘ C and 220 m N / ∘ C, respectively) and higher maximum measurement error (350 m N /10 N , 800 m N /10 N ), comparable to those of FBG-based sensors reported in literature, but are likely to be more suitable for integration in very small

  5. Fundamentals of heat measurement. [heat flux transducers

    NASA Technical Reports Server (NTRS)

    Gerashchenko, O. A.

    1979-01-01

    Various methods and devices for obtaining experimental data on heat flux density over wide ranges of temperature and pressure are examined. Laboratory tests and device fabrication details are supplemented by theoretical analyses of heat-conduction and thermoelectric effects, providing design guidelines and information relevant to further research and development. A theory defining the measure of correspondence between transducer signal and the measured heat flux is established for individual (isolated) heat flux transducers subject to space and time-dependent loading. An analysis of the properties of stacked (series-connected) transducers of various types (sandwich-type, plane, and spiral) is used to derive a similarity theory providing general governing relationships. The transducers examined are used in 36 types of derivative devices involving direct heat loss measurements, heat conduction studies, radiation pyrometry, calorimetry in medicine and industry and nuclear reactor dosimetry.

  6. Micromachined Tunneling Displacement Transducers for Physical Sensors

    NASA Technical Reports Server (NTRS)

    Kenny, T. W.; Kaiser, W. J.; Podosek, J. A.; Rockstad, H. K.; Reynolds, J. K.; Vote, E. C.

    1993-01-01

    We have designed and constructed a series of tunneling sensors which take advantage of the extreme position sensitivity of electron tunneling. In these sensors, a tunneling displacement transducer, based on scanning tunneling microscopy principles, is used to detect the signal-induced motion of a sensor element. Through the use of high-resonant frequency mechanical elements for the transducer, sensors may be constructed which offer wide bandwidth, and are robust and easily operated. Silicon micromachining may be used to fabricate the transducer elements, allowing integration of sensor and control electronics. Examples of tunneling accelerometers and infrared detectors will be discussed. In each case, the use of the tunneling transducer allows miniaturization of the sensor as well as enhancement of the sensor performance.

  7. Guided wave applications of piezocomposite transducers

    SciTech Connect

    Meyer, P.A.; Rose, J.L.

    1996-12-31

    The majority of ultrasonic nondestructive testing applications in use today utilize longitudinal wave techniques. These are very effective for flaw detection and thickness measurement in scanning applications. In sheet and tube type materials, however, a more rapid technique has been developed utilizing Guided Wave Inspection. This method is capable of interrogating large areas of the material without extensive transducer scanning. An important requirement in this method is the ability to utilize relatively broad bandwidth transducers in the test. This paper presents the concepts on which Guided Wave Inspection is based as well as piezocomposite transducer incorporate a combination of piezoelectric ceramics and polymers to enhance the ultrasonic performance of the device. Additionally, the transducer can be designed to match to non-planar surfaces increasing its versatility when a difficult shape is involved.

  8. Portable high precision pressure transducer system

    DOEpatents

    Piper, T.C.; Morgan, J.P.; Marchant, N.J.; Bolton, S.M.

    1994-04-26

    A high precision pressure transducer system is described for checking the reliability of a second pressure transducer system used to monitor the level of a fluid confined in a holding tank. Since the response of the pressure transducer is temperature sensitive, it is continually housed in an battery powered oven which is configured to provide a temperature stable environment at specified temperature for an extended period of time. Further, a high precision temperature stabilized oscillator and counter are coupled to a single board computer to accurately determine the pressure transducer oscillation frequency and convert it to an applied pressure. All of the components are powered by the batteries which during periods of availability of line power are charged by an on board battery charger. The pressure readings outputs are transmitted to a line printer and a vacuum fluorescent display. 2 figures.

  9. AUTOMATIC CALIBRATING SYSTEM FOR PRESSURE TRANSDUCERS

    DOEpatents

    Amonette, E.L.; Rodgers, G.W.

    1958-01-01

    An automatic system for calibrating a number of pressure transducers is described. The disclosed embodiment of the invention uses a mercurial manometer to measure the air pressure applied to the transducer. A servo system follows the top of the mercury column as the pressure is changed and operates an analog- to-digital converter This converter furnishes electrical pulses, each representing an increment of pressure change, to a reversible counterThe transducer furnishes a signal at each calibration point, causing an electric typewriter and a card-punch machine to record the pressure at the instant as indicated by the counter. Another counter keeps track of the calibration points so that a number identifying each point is recorded with the corresponding pressure. A special relay control system controls the pressure trend and programs the sequential calibration of several transducers.

  10. Portable high precision pressure transducer system

    DOEpatents

    Piper, Thomas C.; Morgan, John P.; Marchant, Norman J.; Bolton, Steven M.

    1994-01-01

    A high precision pressure transducer system for checking the reliability of a second pressure transducer system used to monitor the level of a fluid confined in a holding tank. Since the response of the pressure transducer is temperature sensitive, it is continually housed in an battery powered oven which is configured to provide a temperature stable environment at specified temperature for an extended period of time. Further, a high precision temperature stabilized oscillator and counter are coupled to a single board computer to accurately determine the pressure transducer oscillation frequency and convert it to an applied pressure. All of the components are powered by the batteries which during periods of availability of line power are charged by an on board battery charger. The pressure readings outputs are transmitted to a line printer and a vacuum florescent display.

  11. Development of an inherently digital transducer

    NASA Technical Reports Server (NTRS)

    Richard, R. R.

    1972-01-01

    The term digital transducer normally implies the combination of conventional analog sensors with encoders or analog-to-digital converters. Because of the objectionable characteristics of most digital transducers, a program was instituted to investigate the possibility of producing a transducer that is inherently digital, instead of a transducer that is digital in the usual sense. Such a device would have improved accuracy and reliability and would have reduced power and bulk requirements because two processes, sensing and conditioning, would be combined into one processes. A Curie-point-temperature sensor is described that represents realization of the stated goal. Also, a metal-insulator semiconductor is described that does not conform precisely to the program goals but that appears to have applications as a new and interesting transduction device.

  12. Portable high precision pressure transducer system

    NASA Astrophysics Data System (ADS)

    Piper, T. C.; Morgan, J. P.; Marchant, N. J.; Bolton, S. M.

    A high precision pressure transducer system for checking the reliability of a second pressure transducer system used to monitor the level of a fluid confined in a holding tank is presented. Since the response of the pressure transducer is temperature sensitive, it is continually housed in a battery powered oven which is configured to provide a temperature stable environment at specified temperature for an extended period of time. Further, a high precision temperature stabilized oscillator and counter are coupled to a single board computer to accurately determine the pressure transducer oscillation frequency and convert it to an applied pressure. All of the components are powered by the batteries which during periods of availability of line power are charged by an on-board battery charger. The pressure readings outputs are transmitted to a line printer and a vacuum fluorescent display.

  13. Design considerations for piezoelectric polymer ultrasound transducers.

    PubMed

    Brown, L F

    2000-01-01

    Much work has been published on the design of ultrasound transducers using piezoelectric ceramics, but a great deal of this work does not apply when using the piezoelectric polymers because of their unique electrical and mechanical properties. The purpose of this paper is to review and present new insight into seven important considerations for the design of active piezoelectric polymer ultrasound transducers: piezoelectric polymer materials selection, transducer construction and packaging requirements, materials characterization and modeling, film thickness and active area design, electroding selection, backing material design, and front protection/matching layer design. Besides reviewing these design considerations, this paper also presents new insight into the design of active piezoelectric polymer ultrasonic transducers. The design and fabrication of an immersible ultrasonic transducer, which has no adhesive layer between the active element and backing layer, is included. The transducer features direct deposition of poly(vinylidene fluoride-trifluoroethylene) [P(VDF-TrFE)] copolymer onto an insulated aluminum backing substrate. Pulse-echo tests indicated a minimum insertion loss of 37 dB and -6 dB bandwidth of 9.8 to 22 MHz (71%). The use of polymer wear-protection/quarter-wave matching layers is also discussed. Test results on a P(VDF-TrFE) transducer showed that a Mylar/sup TM/ front layer provided a slight increase in pulse-echo amplitude of 15% (or 1.2 dB) and an increase in -6 dB pulse-echo fractional bandwidth from 86 to 95%. Theoretical derivations are reported for optimizing the active area of the piezoelectric polymer element for maximum power transfer at resonance. These derivations are extended to the special case for a low profile (i.e., thin) shielded transducer. A method for modeling the non-linear loading effects of a commercial pulser-receiver is also included.

  14. Ultrasonic transducer for extreme temperature environments

    DOEpatents

    Light, Glenn M.; Cervantes, Richard A.; Alcazar, David G.

    1993-03-23

    An ultrasonic piezoelectric transducer that is operable in very high and very low temperatures. The transducer has a dual housing structure that isolates the expansion and contraction of the piezoelectric element from the expansion and contraction of the housing. Also, the internal components are made from materials having similar coefficients of expansion so that they do not interfere with the motion of the piezoelectric element.

  15. Resonant capacitive MEMS acoustic emission transducers

    NASA Astrophysics Data System (ADS)

    Ozevin, D.; Greve, D. W.; Oppenheim, I. J.; Pessiki, S. P.

    2006-12-01

    We describe resonant capacitive MEMS transducers developed for use as acoustic emission (AE) detectors, fabricated in the commercial three-layer polysilicon surface micromachining process (MUMPs). The 1 cm square device contains six independent transducers in the frequency range between 100 and 500 kHz, and a seventh transducer at 1 MHz. Each transducer is a parallel plate capacitor with one plate free to vibrate, thereby causing a capacitance change which creates an output signal in the form of a current under a dc bias voltage. With the geometric proportions we employed, each transducer responds with two distinct resonant frequencies. In our design the etch hole spacing was chosen to limit squeeze film damping and thereby produce an underdamped vibration when operated at atmospheric pressure. Characterization experiments obtained by capacitance and admittance measurements are presented, and transducer responses to physically simulated AE source are discussed. Finally, we report our use of the device to detect acoustic emissions associated with crack initiation and growth in weld metal.

  16. High energy, low frequency, ultrasonic transducer

    DOEpatents

    Brown, Albert E.

    2000-01-01

    A wide bandwidth, ultrasonic transducer to generate nondispersive, extensional, pulsed acoustic pressure waves into concrete reinforced rods and tendons. The wave propagation distance is limited to double the length of the rod. The transducer acoustic impedance is matched to the rod impedance for maximum transfer of acoustic energy. The efficiency of the transducer is approximately 60 percent, depending upon the type of active elements used in the transducer. The transducer input energy is, for example, approximately 1 mJ. Ultrasonic reflections will occur at points along the rod where there are changes of one percent of a wavelength in the rod diameter. A reduction in the rod diameter will reflect a phase reversed echo, as compared with the reflection from an incremental increase in diameter. Echo signal processing of the stored waveform permits a reconstruction of those echoes into an image of the rod. The ultrasonic transducer has use in the acoustic inspection of long (40+foot) architectural reinforcements and structural supporting members, such as in bridges and dams.

  17. Comparison of piezoresistive and capacitive ultrasonic transducers

    NASA Astrophysics Data System (ADS)

    Neumann, John J.; Greve, David W.; Oppenheim, Irving J.

    2004-07-01

    MEMS ultrasonic transducers for flaw detection have heretofore been built as capacitive diaphragm-type devices. A diaphragm forms a moveable electrode, placed at a short gap from a stationary electrode, and diaphragm movement has been detected by capacitance change. Although several research teams have successfully demonstrated that technology, the detection of capacitance change is adversely affected by stray and parasitic capacitances, limiting the sensitivity of such transducers and typically requiring relatively large diaphragm areas. We describe the design and fabrication of what to our knowledge is the first CMOS-MEMS ultrasonic phased array transducer using piezoresistive strain sensing. Piezoresistors have been patterned within the diaphragms, and diaphragm movement creates bending strain which is detected by a bridge circuit, for which conductor losses will be less significant. The prospective advantage of such piezoresistive transducers is that sufficient sensitivity may be achieved with very small diaphragms. We compare transducer response under fluid-coupled ultrasonic excitation and report the experimental gauge factor for the piezoresistors. We also discuss the phased array performance of the transducer in sensing the direction of an incoming wave.

  18. [Comparative investigation of the discharge characteristics of a single needle jet and needle-plate jet].

    PubMed

    Li, Xue-Chen; Chang, Yuan-Yuan; Jia, Peng-Ying; Zhao, Huan-Huan; Liu, Run-Fu; Di, Cong

    2013-04-01

    In the present paper, discharge characteristics were studied in atmospheric pressure argon by a single needle jet and needle-plate jet through combination of optical measurement and electrical one. Results show that the length and cross-sectional area of the plasmas generated in the two jets increase with increasing the peak value of the applied voltage. The cross-sectional area generated by needle-plate jet is bigger than that of the single needle jet at the same voltage. A lower inception voltage is needed for the needle-plate jet compared with the single needle jet at the same U(p). Through the spectra emitted from the two jets, electron temperature and vibration temperature wee compared for the plasmas generated by the single needle jet and needle-plate jet, respectively. It can be found that the electron temperature and the vibrational temperature of the two jets increase with increasing U(p). The needle-plate jet has higher values of electron temperature and vibrational temperature than the single needle jet at the same U(p). These results have significant values for the industrial application of the atmospheric pressure plasma jet.

  19. The Biological Safety of Stainless Steel Needles Used in Warm-needling.

    PubMed

    Lim, Sabina; Lee, Seunghun; Yi, Seung-Ho; Son, Yang-Sun; Choi, Sung-Min; Kim, Young-Kon

    2010-06-01

    Warm-needling (also called thermo-acupuncture) is a combination of acupuncture and moxibustion. Due to the intense heat involved, there have been concerns over the biological safety of the acuneedles used in the treatment. This paper reports two phases of a safety test. For a preliminary test, we compared the temperature change patterns of stainless steel (SS304) needles and traditional gold alloy needles, which have been increasingly replaced by the former. To verify the effects of the presence of coating materials, the main test involved three different kinds of SS304: silicone-coated, salicylic acid-coated and non-coated needles. Each group of needles was tested for pH level, heavy metals and UV absorbance spectrum along with biological tests on the cytotoxicity and hemolysis of the needle. All the tests on the extractants from the needles were negative. In the biological tests, each test result showed a significant difference from the positive control samples, while no significant difference was observed compared with the negative control samples. In the hemolysis tests, all samples satisfied the Korean Government Standards. All the results suggest that SS304 needles are biologically safe to be used in warm-needling, though they can be improved to perform as well as the gold alloy needles in terms of temperature fluctuations.

  20. 21 CFR 870.2860 - Heart sound transducer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Heart sound transducer. 870.2860 Section 870.2860...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2860 Heart sound transducer. (a) Identification. A heart sound transducer is an external transducer that exhibits a change...

  1. 21 CFR 870.2860 - Heart sound transducer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Heart sound transducer. 870.2860 Section 870.2860...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2860 Heart sound transducer. (a) Identification. A heart sound transducer is an external transducer that exhibits a change...

  2. 21 CFR 870.2860 - Heart sound transducer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Heart sound transducer. 870.2860 Section 870.2860...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2860 Heart sound transducer. (a) Identification. A heart sound transducer is an external transducer that exhibits a change...

  3. 21 CFR 870.2860 - Heart sound transducer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Heart sound transducer. 870.2860 Section 870.2860...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2860 Heart sound transducer. (a) Identification. A heart sound transducer is an external transducer that exhibits a change...

  4. 21 CFR 870.2860 - Heart sound transducer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Heart sound transducer. 870.2860 Section 870.2860...) MEDICAL DEVICES CARDIOVASCULAR DEVICES Cardiovascular Monitoring Devices § 870.2860 Heart sound transducer. (a) Identification. A heart sound transducer is an external transducer that exhibits a change...

  5. 21 CFR 870.2890 - Vessel occlusion transducer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ..., sound, and ultrasonic transducers. (b) Classification. Class II (performance standards). ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Vessel occlusion transducer. 870.2890 Section 870... transducer. (a) Identification. A vessel occlusion transducer is a device used to provide an...

  6. 21 CFR 870.2890 - Vessel occlusion transducer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ..., sound, and ultrasonic transducers. (b) Classification. Class II (performance standards). ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Vessel occlusion transducer. 870.2890 Section 870... transducer. (a) Identification. A vessel occlusion transducer is a device used to provide an...

  7. Micromachined PIN-PMN-PT crystal composite transducer for high-frequency intravascular ultrasound (IVUS) imaging.

    PubMed

    Li, Xiang; Ma, Teng; Tian, Jian; Han, Pengdi; Zhou, Qifa; Shung, K Kirk

    2014-07-01

    In this paper, we report the use of micromachined PbIn1/2Nb1/2O3-PbMg1/3Nb2/3O3-PbTiO 3 (PIN-PMNPT) single crystal 1-3 composite material for intravascular ultrasound (IVUS) imaging application. The effective electromechanical coupling coefficient kt(eff) of the composite was measured to be 0.75 to 0.78. Acoustic impedance was estimated to be 20 MRayl. Based on the composite, needle-type and flexible-type IVUS transducers were fabricated. The composite transducer achieved an 86% bandwidth at the center frequency of 41 MHz, which resulted in a 43 μm axial resolution. Ex vivo IVUS imaging was conducted to demonstrate the improvement of axial resolution. The composite transducer was capable of identifying the three layers of a cadaver coronary artery specimen with high resolution. The PIN-PMN-PT-based composite has superior piezoelectric properties comparable to PMN-PT-based composite and its thermal stability is higher than PMN-PT. PIN-PMN-PT crystal can be an alternative approach for fabricating high-frequency composite, instead of using PMN-PT.

  8. Micromachined PIN-PMN-PT Crystal Composite Transducer for High-Frequency Intravascular Ultrasound (IVUS) Imaging

    PubMed Central

    Li, Xiang; Ma, Teng; Tian, Jian; Han, Pengdi; Zhou, Qifa; Shung, K. Kirk

    2015-01-01

    In this paper, we report the use of micromachined PbIn1/2Nb1/2O3–PbMg1/3Nb2/3O3–PbTiO3 (PIN-PMN-PT) single crystal 1–3 composite material for intravascular ultrasound (IVUS) imaging application. The effective electromechanical coupling coefficient kt(eff) of the composite was measured to be 0.75 to 0.78. Acoustic impedance was estimated to be 20 MRayl. Based on the composite, needle-type and flexible-type IVUS transducers were fabricated. The composite transducer achieved an 86% bandwidth at the center frequency of 41 MHz, which resulted in a 43 μm axial resolution. Ex vivo IVUS imaging was conducted to demonstrate the improvement of axial resolution. The composite transducer was capable of identifying the three layers of a cadaver coronary artery specimen with high resolution. The PIN-PMN-PT-based composite has superior piezoelectric properties comparable to PMN-PT-based composite and its thermal stability is higher than PMN-PT. PIN-PMN-PT crystal can be an alternative approach for fabricating high-frequency composite, instead of using PMN-PT. PMID:24960706

  9. [Approach to teaching methods of the needling skill of filiform needle].

    PubMed

    Wang, Cai-Hong; Xu, Jian-Min; Wang, Yin-Ping; Li, Yi

    2008-08-01

    The present paper is armed at approach to a set of teaching method about the needling skill of filiform needle, so as to increase teaching quality. After review and analysis on present situation of teaching methods about the needling skill of filiform needle, it is raised that traditional teaching methods are unable to objectively and comprehensively reflect characteristics and requirement of manipulation, so try to adopt acupuncture manipulation detection instrument, on the basis of traditional teaching methods about the needling skill of filiform needle. And the parameters and figures of manipulation examine of real-time collection in 131 students and information of 120 copies of questionnaire are analyzed and summarized. It is indicated that combined teaching method of traditional model and the manipulation instrument is more reasonable, and basic manipulation training most he strengthened in manipulation skill training, particularly, pay attention to training of twirling manipulation.

  10. Needle-Tissue Interaction Forces for Bevel-Tip Steerable Needles

    PubMed Central

    Misra, Sarthak; Reed, Kyle B.; Douglas, Andrew S.; Ramesh, K. T.; Okamura, Allison M.

    2010-01-01

    The asymmetry of a bevel-tip needle results in the needle naturally bending when it is inserted into soft tissue. As a first step toward modeling the mechanics of deflection of the needle, we determine the forces at the bevel tip. In order to find the forces acting at the needle tip, we measure rupture toughness and nonlinear material elasticity parameters of several soft tissue simulant gels and chicken tissue. We incorporate these physical parameters into a finite element model that includes both contact and cohesive zone models to simulate tissue cleavage. We investigate the sensitivity of the tip forces to tissue rupture toughness, linear and nonlinear tissue elasticity, and needle tip bevel angle. The model shows that the tip forces are sensitive to the rupture toughness. The results from these studies contribute to a mechanics-based model of bevel-tip needle steering, extending previous work on kinematic models. PMID:22020139

  11. Needle-Tissue Interaction Forces for Bevel-Tip Steerable Needles.

    PubMed

    Misra, Sarthak; Reed, Kyle B; Douglas, Andrew S; Ramesh, K T; Okamura, Allison M

    2008-10-19

    The asymmetry of a bevel-tip needle results in the needle naturally bending when it is inserted into soft tissue. As a first step toward modeling the mechanics of deflection of the needle, we determine the forces at the bevel tip. In order to find the forces acting at the needle tip, we measure rupture toughness and nonlinear material elasticity parameters of several soft tissue simulant gels and chicken tissue. We incorporate these physical parameters into a finite element model that includes both contact and cohesive zone models to simulate tissue cleavage. We investigate the sensitivity of the tip forces to tissue rupture toughness, linear and nonlinear tissue elasticity, and needle tip bevel angle. The model shows that the tip forces are sensitive to the rupture toughness. The results from these studies contribute to a mechanics-based model of bevel-tip needle steering, extending previous work on kinematic models.

  12. [Discussion on needling sensation, arrival of qi and needling response (Deqi)].

    PubMed

    Zhang, Fang; Wang, Hong-Du

    2012-12-01

    The current appointed teaching material of Science of Acupuncture and Moxibustion holds that there is no difference among the needling sensation, arrival of qi and needling response. However, the author has a different understanding. Therefore, Neijing (Internal Classic), its annotation, exposition and understandings of ancient and modern famous experts are cited to analyze their meanings. And the result indicates that the needling sensation is subjective feelings and perceived responses of doctors and patients. Arrival of qi is the healing process of the organ through activating the anti-pathogenic qi to expel the pathogens. The needling response is the final aim of acupuncture therapy. Thus, the meaning of needling sensation, arrival of qi, and needling response are different. And an accurate understanding can better guide acupuncture treatment.

  13. Pine needle abortion biomarker detected in bovine fetal fluids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Pine needle abortion is a naturally occurring condition in free-range cattle caused by the consumption of pine needles from select species of cypress, juniper, pine, and spruce trees. Confirmatory diagnosis of pine needle abortion has previously relied on a combined case history of pine needle cons...

  14. Some Strip Contributions to Transducer Design and Analysis

    DTIC Science & Technology

    1989-04-28

    19951116 110 14. SUBJECT TERMS Sonar transducers , Tonpilz transducers , ku-mode transducers , 15. NUMBER OF PAGES Piezoelectric ceramic, Ceramic stack...PRACTICAL ILLUSTRATIONS OF THE SGM ANALYSIS ................. 149 B.1 THE IN-WATER SGM RESULTS OF THE STR-330A TONPILZ TRANSDUCER M O D E L...150 B.2 THE IN-WATER SGM RESULTS OF THE STR-330A TONPILZ TRANSDUCER MODEL: VARIABLE mH, FIXED mTAND com

  15. Science off the Sphere: Knitting Needles

    NASA Video Gallery

    International Space Station Expedition 30 astronaut Don Pettit uses knitting needles and water droplets to demonstrate physics in space for 'Science off the Sphere.' Through a partnership between N...

  16. Sliding Mode Control of Steerable Needles

    PubMed Central

    Rucker, D. Caleb; Das, Jadav; Gilbert, Hunter B.; Swaney, Philip J.; Miga, Michael I.; Sarkar, Nilanjan; Webster, Robert J.

    2014-01-01

    Steerable needles can potentially increase the accuracy of needle-based diagnosis and therapy delivery, provided they can be adequately controlled based on medical image information. We propose a novel sliding mode control law that can be used to deliver the tip of a flexible asymmetric-tipped needle to a desired point, or to track a desired trajectory within tissue. The proposed control strategy requires no a priori knowledge of model parameters, has bounded input speeds, and requires little computational resources. We show that if the standard nonholonomic model for tip-steered needles holds, then the control law will converge to desired targets in a reachable workspace, within a tolerance that can be defined by the control parameters. Experimental results validate the control law for target points and trajectory following in phantom tissue and ex vivo liver. Experiments with targets that move during insertion illustrate robustness to disturbances caused by tissue deformation. PMID:25400527

  17. Sliding Mode Control of Steerable Needles.

    PubMed

    Rucker, D Caleb; Das, Jadav; Gilbert, Hunter B; Swaney, Philip J; Miga, Michael I; Sarkar, Nilanjan; Webster, Robert J

    2013-10-01

    Steerable needles can potentially increase the accuracy of needle-based diagnosis and therapy delivery, provided they can be adequately controlled based on medical image information. We propose a novel sliding mode control law that can be used to deliver the tip of a flexible asymmetric-tipped needle to a desired point, or to track a desired trajectory within tissue. The proposed control strategy requires no a priori knowledge of model parameters, has bounded input speeds, and requires little computational resources. We show that if the standard nonholonomic model for tip-steered needles holds, then the control law will converge to desired targets in a reachable workspace, within a tolerance that can be defined by the control parameters. Experimental results validate the control law for target points and trajectory following in phantom tissue and ex vivo liver. Experiments with targets that move during insertion illustrate robustness to disturbances caused by tissue deformation.

  18. Inverse Kinematics of Concentric Tube Steerable Needles

    PubMed Central

    Sears, Patrick; Dupont, Pierre E.

    2013-01-01

    Prior papers have introduced steerable needles composed of precurved concentric tubes. The curvature and extent of these needles can be controlled by the relative rotation and translation of the individual tubes. Under certain assumptions on the geometry and design of these needles, the forward kinematics problem can be solved in closed form by means of algebraic equations. The inverse kinematics problem, however, is not as straightforward owing to the nonlinear map between relative tube displacements and needle tip configuration as well as to the multiplicity of solutions as the number of tubes increases. This paper presents a general approach to solving the inverse kinematics problem using a pseudoinverse solution together with gradients of nullspace potential functions to enforce geometric and mechanical constraints. PMID:23685532

  19. An illuminated flute needle for vitreoretinal surgery.

    PubMed

    Davison, C N; Rosen, P H

    1994-06-01

    We have developed a simple self-illuminated flute needle for internal drainage of subretinal fluid during three-port vitrectomy. This instrument facilitates visualization and drainage through peripheral retinal breaks.

  20. A Multi-Layered Needle Injection Simulator.

    PubMed

    Laufer, Shlomi; Kempton, Steve J; Maciolek, Kimberly; Terry, Aliyya; Ray, Rebeca D; Pugh, Carla M; Afifi, Ahmed M

    2016-01-01

    Insuring correct needle location is crucial in many medical procedures. This can be even more challenging for physicians injecting in a new location for the first time. Since they do not necessarily know how the tissue is supposed to feel, finding the correct location and correct depth can be difficult. In this study we designed a simulator for training needle injection. The simulator was fabricated to give a realistic feeling of injecting Botox® in the temporalis and the semispinalis muscles as part of migraine treatment. In addition the simulator provided real-time feedback of correct needle location. Nine residents and medical students evaluated the simulator. They made several errors that were corrected real time using the real time feedback provided. They found the simulator to be very useful and that the training significantly improved their confidence. The methods described in this study can easily be implemented for developing needle injection simulators for other anatomical locations.

  1. Amorphous force transducers in ac applications

    NASA Astrophysics Data System (ADS)

    Meydan, T.; Overshott, K. J.

    1982-11-01

    The high stress sensitivity and high yield stress properties of amorphous ribbon materials make them suitable for magnetic sensors and tranducer applications. Recently the authors have shown that ac systems eliminate the offset voltage and drift problems of the previously published dc systems. Further investigations proved that these transducers could be operated with a linear characteristic up to 1000 g in multiwrap toroidal configurations. The cause of the transducing behavior of the materials was proved to be variation of permeability with stress. It was previously suggested that the optimum operating frequency of the ac transducers is dependent on the physical configuration of the core. Further investigations have shown that the optimum operating frequency is linearly dependent on the amplitude of the input signal to the transducer. Double-core systems have been previously described in the literature where one core acts as a dummy core and the force is applied to the active core. The disadvantage of the double-core system is that aging of the active core changes the performance of the transducer by as much as 10%. A new system will be presented which uses an accurate analog memory to reduce the ageing effect to a fraction of one percent.

  2. High temperature, high power piezoelectric composite transducers.

    PubMed

    Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, Stewart

    2014-08-08

    Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined.

  3. High Temperature, High Power Piezoelectric Composite Transducers

    PubMed Central

    Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, StewarT.

    2014-01-01

    Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined. PMID:25111242

  4. Ultrasound-Guided Needle Technique Accuracy

    PubMed Central

    Johnson, Angela N.; Peiffer, Jeffery S.; Halmann, Nahi; Delaney, Luke; Owen, Cindy A.; Hersh, Jeff

    2017-01-01

    Background and Objectives Ultrasound-guided regional anesthesia facilitates an approach to sensitive targets such as nerve clusters without contact or inadvertent puncture. We compared accuracy of needle placement with a novel passive magnetic ultrasound needle guidance technology (NGT) versus conventional ultrasound (CU) with echogenic needles. Methods Sixteen anesthesiologists and 19 residents performed a series of 16 needle insertion tasks each, 8 using NGT (n = 280) and 8 using CU (n = 280), in high-fidelity porcine phantoms. Tasks were stratified based on aiming to contact (target-contact) or place in close proximity with (target-proximity) targets, needle gauge (no. 18/no. 22), and in-plane (IP) or out-of-plane (OOP) approach. Distance to the target, task completion by aim, number of passes, and number of tasks completed on the first pass were reported. Results Needle guidance technology significantly improved distance, task completion, number of passes, and completion on the first pass compared with CU for both IP and OOP approaches (P ≤ 0.001). Average NGT distance to target was lower by 57.1% overall (n = 560, 1.5 ± 2.4 vs 3.5 ± 3.7 mm), 38.5% IP (n = 140, 1.6 ± 2.6 vs 2.6 ± 2.8 mm), and 68.2% OOP (n = 140, 1.4 ± 2.2 vs 4.4 ± 4.3 mm) (all P ≤ 0.01). Subgroup analyses revealed accuracy gains were largest among target-proximity tasks performed by residents and for OOP approaches. Needle guidance technology improved first-pass completion from 214 (76.4%) per 280 to 249 (88.9%) per 280, a significant improvement of 16.4% (P = 0.001). Conclusions Passive magnetic NGT can improve accuracy of needle procedures, particularly among OOP procedures requiring close approach to sensitive targets, such as nerve blocks in anesthesiology practice. PMID:28079754

  5. The improvement on the falling needle viscometer

    NASA Astrophysics Data System (ADS)

    Sha, Zhen-Shun

    1997-04-01

    To overcome the shortcomings of the conventional falling needle viscometer, many improvements have been made, e.g., adopting new design of needle structure, collector, and launcher. Furthermore, Hall magnetic sensors and single-board computer are used in the system, which makes the measurement automatic and intelligent. It is proved in the experiment that the instrument is accurate enough and has excellent performance. The technique can also be applied in falling ball viscometers.

  6. Dry needling versus acupuncture: the ongoing debate.

    PubMed

    Zhou, Kehua; Ma, Yan; Brogan, Michael S

    2015-12-01

    Although Western medical acupuncture (WMA) is commonly practised in the UK, a particular approach called dry needling (DN) is becoming increasingly popular in other countries. The legitimacy of the use of DN by conventional non-physician healthcare professionals is questioned by acupuncturists. This article describes the ongoing debate over the practice of DN between physical therapists and acupuncturists, with a particular emphasis on the USA. DN and acupuncture share many similarities but may differ in certain aspects. Currently, little information is available from the literature regarding the relationship between the two needling techniques. Through reviewing their origins, theory, and practice, we found that DN and acupuncture overlap in terms of needling technique with solid filiform needles as well as some fundamental theories. Both WMA and DN are based on modern biomedical understandings of the human body, although DN arguably represents only one subcategory of WMA. The increasing volume of research into needling therapy explains its growing popularity in the musculoskeletal field including sports medicine. To resolve the debate over DN practice, we call for the establishment of a regulatory body to accredit DN courses and a formal, comprehensive educational component and training for healthcare professionals who are not physicians or acupuncturists. Because of the close relationship between DN and acupuncture, collaboration rather than dispute between acupuncturists and other healthcare professionals should be encouraged with respect to education, research, and practice for the benefit of patients with musculoskeletal conditions who require needling therapy.

  7. Dominant hand operating probe vs needle: a comparison study of ultrasound-guided needle placement in phantom models.

    PubMed

    Johnston, D F; Stafford, M

    2015-08-01

    We conducted a replicated crossover design study to assess if using one's dominant hand for operating a probe vs directing a needle would affect the time taken, the number of needle passes and the accuracy of an ultrasound-guided procedure in phantom models. Twenty ultrasound-novice participants completed the task 10 times for each hand arrangement (alternating between attempts). The time taken and number of needle passes required for both dominant hand-probe and hand-needle decreased over time (p = 0.001). Dominant hand-needle had a lower mean time used (p = 0.001) and fewer needle passes (p = 0.02) compared with hand-probe. Sixty-five per cent of participants preferred using their dominant hand to direct the needle. When learning ultrasound-guided needle procedures on phantom models, use of the dominant hand to operate the needle is associated with a shorter procedure time and fewer needle passes.

  8. Acoustooptic pulse-echo transducer system

    NASA Technical Reports Server (NTRS)

    Claus, R. O.; Wade, J. C.

    1983-01-01

    A pulse-echo transducer system which uses an ultrasonic generating element and an optical detection technique is described. The transmitting transducer consists of a concentric ring electrode pattern deposited on a circular, X-cut quartz substrate with a circular hole in the center. The rings are independently pulsed with a sequence high voltage signals phased in such a way that the ultrasonic waves generated by the separate rings superimpose to produce a composite field which is focused at a controllable distance below the surface of the specimen. The amplitude of the field reflected from this focus position is determined by the local reflection coefficient of the medium at the effective focal point. By processing the signals received for a range of ultrasonic transducer array focal lengths, the system can be used to locate and size anomalies within solids and liquids. Applications in both nondestructive evaluation and biomedical scanning are suggested.

  9. Torque transducer based on fiber Bragg grating

    NASA Astrophysics Data System (ADS)

    Li, Tao; Jiang, Shu; Li, Jiang; Lin, Jiejun; Qi, Hongli

    2016-11-01

    In order to obtain the accurate torque measurements in harsh condition, such as marine environment, a torque transducer based on fiber Bragg grating is proposed in this paper. According to its optimized elastomer design and fiber Bragg grati ng patching tactics, the new proposed torque transducer realizes automatic compensations of temperature and bending moment which avoids influences from environment. The accuracy and stability of the torquetransducer, as well as its under water performance are tested by loading tests both in air and in underwater environment, which indicate the designed tor que transducer is not only able to realize highaccurate and robust measurements, but also can be applied in torque sensing in harsh environment. We believe the proposed design detailed illustrated in this paper provides important reference for studies and applications on torque measurements in marine environment.

  10. Protein family classification using sparse Markov transducers.

    PubMed

    Eskin, E; Grundy, W N; Singer, Y

    2000-01-01

    In this paper we present a method for classifying proteins into families using sparse Markov transducers (SMTs). Sparse Markov transducers, similar to probabilistic suffix trees, estimate a probability distribution conditioned on an input sequence. SMTs generalize probabilistic suffix trees by allowing for wild-cards in the conditioning sequences. Because substitutions of amino acids are common in protein families, incorporating wildcards into the model significantly improves classification performance. We present two models for building protein family classifiers using SMTs. We also present efficient data structures to improve the memory usage of the models. We evaluate SMTs by building protein family classifiers using the Pfam database and compare our results to previously published results.

  11. Sonar Transducer Reliability Improvement Program FY 80

    DTIC Science & Technology

    1980-10-01

    Polyphenylene Sulfide 15,320 23,000 Nylon 6/10 14,070 26,000 High-Strength Nylon (ZYTEL) 11,270 24,000 Amorphous Nylon 14,139 25,000 PBT Polyester...transducer receiving sensitivity Goal -- less than ±1 dB variation from the specified value over operational frequency band . Threshold - less than ±2 dB...variation from the specified value over operational feequency band . rhe Sonar Transducer Reliability Impruvemen: Program (STRIP) is a part of Program

  12. Pressure transducer and system for cryogenic environments

    NASA Technical Reports Server (NTRS)

    Chapman, John J. (Inventor)

    1992-01-01

    A silicon pressure die is bonded to a borosilicate substrate above the pneumatic port. A Wheatstone bridge circuit is formed on the silicon pressure die and has bridge elements of silicon doped with boron to a deposit density level of approximately 1 x 10(exp 19)-10(exp 21) boron/cc. A current source is provided to excite the Wheatstone bridge circuit. In addition, a temperature sensor is provided to provide temperature readings. An array may be formed of the resulting pressure transducers. This unique solution of materials permits operation of a pressure transducer in cryogenic environments.

  13. Ultrasonic transducer with laminated coupling wedge

    DOEpatents

    Karplus, Henry H. B.

    1976-08-03

    An ultrasonic transducer capable of use in a high-temperature environment incorporates a laminated metal coupling wedge including a reflecting edge shaped as a double sloping roof and a transducer crystal backed by a laminated metal sound absorber disposed so as to direct sound waves through the coupling wedge and into a work piece, reflections from the interface between the coupling wedge and the work piece passing to the reflecting edge. Preferably the angle of inclination of the two halves of the reflecting edge are different.

  14. Mechano-electric optoisolator transducer with hysteresis

    NASA Astrophysics Data System (ADS)

    Ciuruş, I. M.; Dimian, M.; Graur, A.

    2011-01-01

    This article presents a theoretical and experimental study of designing a mechano-electric optoisolator transducer with hysteresis. Our research is centred upon designing transducers on the basis of optical sensors, as photoelectric conversions eliminate the influence of electromagnetic disturbances. Conversion of the rotation/translation motions into electric signals is performed with the help of a LED-photoresistor Polaroid optocoupler. The driver of the optocoupler's transmitter module is an independent current source. The signal conditioning circuit is a Schmitt trigger circuit. The device is designed to be applied in the field of automation and mechatronics.

  15. The simulation model of planar electrochemical transducer

    NASA Astrophysics Data System (ADS)

    Zhevnenko, D. A.; Vergeles, S. S.; Krishtop, T. V.; Tereshonok, D. V.; Gornev, E. S.; Krishtop, V. G.

    2016-12-01

    Planar electrochemical systems are very perspective to build modern motion and pressure sensors. Planar microelectronic technology is successfully used for electrochemical transducer of motion parameters. These systems are characterized by an exceptionally high sensitivity towards mechanic exposure due to high rate of conversion of the mechanic signal to electric current. In this work, we have developed a mathematical model of this planar electrochemical system, which detects the mechanical signals. We simulate the processes of mass and charge transfer in planar electrochemical transducer and calculated its transfer function with different geometrical parameters of the system.

  16. The Calibrations of Space Shuttle Main Engines High Pressure Transducers

    NASA Technical Reports Server (NTRS)

    Steward, Christopher S.

    1995-01-01

    Previously, high pressure transducers that were used on the Space Shuttles Main Engine (SSME) exhibited a severe drift after being tested on the SSME. The Experimental Testing Technology Division (ETTD) designed some new transducers that would not exhibit a severe drift over a short period of time. These transducers were calibrated at the Test Bed at Marshall Space Flight Center (MSFC). After the high pressure transducers were calibrated, the transducers were placed on the SSME and fired. The transducers were then sent to the NASA LaRC to be recalibrated. The main objectives of the recalibrations was to make sure that the transducers possessed the same qualities as they did before they were fired on the SSME. Other objectives of the project were to determine the stability of the transducers and to determine whether the transducers exhibited a severe drift.

  17. Comparison of Spinal Needle Deflection in a Ballistic Gel Model

    PubMed Central

    Rand, Ethan; Christolias, George; Visco, Christopher; R. Singh, Jaspal

    2016-01-01

    Background Percutaneous diagnostic and therapeutic procedures are commonly used in the treatment of spinal pain. The success of these procedures depends on the accuracy of needle placement, which is influenced by needle size and shape. Objectives The purpose of this study is to examine and quantify the deviation of commonly used spinal needles based on needle tip design and gauge, using a ballistic gel tissue simulant. Materials and Methods Six needles commonly used in spinal procedures (Quincke, Short Bevel, Chiba, Tuohy, Hustead, Whitacre) were selected for use in this study. Ballistic gel samples were made in molds of two depths, 40mm and 80 mm. Each needle was mounted in a drill press to ensure an accurate needle trajectory. Distance of deflection was recorded for each needle. Results In comparing the mean deflection of 22 gauge needles of all types at 80 mm of depth, deflection was greatest among beveled needles [Short Bevel (9.96 ± 0.77 mm), Quincke (8.89 ± 0.17 mm), Chiba (7.71 ± 1.16 mm)], moderate among epidural needles [Tuohy (7.64 ± 0.16 mm) and least among the pencil-point needles [Whitacre (0.73 ± 0.34 mm)]. Increased gauge (25 g) led to a significant increase in deflection among beveled needles. The direction of deflection was away from the bevel with Quincke, Chiba and Short Beveled needles and toward the bevel of the Tuohy and Hustead needles. Deflection of the Whitacre pencil-point needle was minimal. Conclusions There is clinical utility in knowing the relative deflection of various needle tips. When a procedure requires a needle to be steered around obstacles, or along non-collinear targets, the predictable and large amount of deflection obtained through use of a beveled spinal needle may prove beneficial. PMID:27847693

  18. Transbronchial needle aspiration with a new electromagnetically-tracked TBNA needle

    NASA Astrophysics Data System (ADS)

    Choi, Jae; Popa, Teo; Gruionu, Lucian

    2009-02-01

    Transbronchial needle aspiration (TBNA) is a common method used to collect tissue for diagnosis of different chest diseases and for staging lung cancer, but the procedure has technical limitations. These limitations are mostly related to the difficulty of accurately placing the biopsy needles into the target mass. Currently, pulmonologists plan TBNA by examining a number of Computed Tomography (CT) scan slices before the operation. Then, they manipulate the bronchoscope down the respiratory track and blindly direct the biopsy. Thus, the biopsy success rate is low. The diagnostic yield of TBNA is approximately 70 percent. To enhance the accuracy of TBNA, we developed a TBNA needle with a tip position that can be electromagnetically tracked. The needle was used to estimate the bronchoscope's tip position and enable the creation of corresponding virtual bronchoscopic images from a preoperative CT scan. The TBNA needle was made with a flexible catheter embedding Wang Transbronchial Histology Needle and a sensor tracked by electromagnetic field generator. We used Aurora system for electromagnetic tracking. We also constructed an image-guided research prototype system incorporating the needle and providing a user-friendly interface to assist the pulmonologist in targeting lesions. To test the feasibility of the accuracy of the newly developed electromagnetically-tracked needle, a phantom study was conducted in the interventional suite at Georgetown University Hospital. Five TBNA simulations with a custom-made phantom with a bronchial tree were performed. The experimental results show that our device has potential to enhance the accuracy of TBNA.

  19. Consideration of Design Parameters of Ultrasonic Transducer for Fruit

    NASA Astrophysics Data System (ADS)

    Kim, K. B.; Kim, M. S.; Lee, S. D.; Choi, M. Y.

    2005-04-01

    This study was conducted to develop the ultrasonic transducers for non-destructive contact measurement of fruits. The design parameters for ultrasonic transducer such as acoustical impedance of fruits, kinds of piezoelectric materials, ultrasonic wave frequency, and transducer diameter were investigated. In order to match the impedance between piezoelectric material and fruit, various materials were evaluated. And to control the bandwidth of ultrasonic wave of the transducer, various backing materials were fabricated and evaluated. Especially, the wear plate of the transducer was designed and fabricated considering curvature of fruit. Finally, the ultrasonic transducer having 100 kHz of central frequency were fabricated and tested.

  20. Applications of the Method for Transducer Transient Suppression to Various Transducer Types

    DTIC Science & Technology

    1993-08-01

    previously. These types are (i) flexural disk, (ii) Helmholtz resonator, (iii) moving coil, (iv) inductor-tuned Tonpilz , and (v)a dual transducer array of...previously. These types are (i) flexural disk. (ii) Helmholtz resonator, (iii) moving coil, (iv) inductor-tuned Tonpilz , and (v) a dual transducer array of...cycle case, we findV(O -- t-- +i, R (t;>r. even number of half-cycles), (3) FIG. 2. Equivalent circuit for an inductor-tuned Tonpilz transducer . The

  1. Modeling of Needle-Tissue Interaction Forces During Surgical Suturing

    PubMed Central

    Jackson, Russell C.; Çavuşoğlu, M. Cenk

    2013-01-01

    This paper presents a model of needle tissue interaction forces that a rigid suture needle experiences during surgical suturing. The needle-tissue interaction forces are modeled as the sum of lumped parameters. The model has three main components; friction, tissue compression, and cutting forces. The tissue compression force uses the area that the needle sweeps out during a suture to estimate both the force magnitude and force direction. The area that the needle sweeps out is a direct result of driving the needle in a way that does not follow the natural curve of the needle. The friction force is approximated as a static friction force along the shaft of the needle. The cutting force acts only on the needle tip. The resulting force and torque model is experimentally validated using a tissue phantom. These results indicate that the proposed lumped parameter model is capable of accurately modeling the forces experienced during a suture. PMID:24683499

  2. Characterization of Pre-Curved Needles for Steering in Tissue

    PubMed Central

    Wedlick, Thomas R.; Okamura, Allison M.

    2010-01-01

    Needles with tip asymmetry deflect upon insertion into soft tissue, an effect that can be used to steer needles within the body. This paper presents a phenomenological characterization of the steering behavior of pre-curved needles, which have tip asymmetry due to curvature of the needle near the tip. We describe needle construction methods and a needle shaft triangulation algorithm to compute the shape of the needle based on images. Experimental results show that pre-curved needles possess greater dexterity than bevel-tipped needles and achieve radii of curvature similar to pre-bent needles. For long pre-curve arc lengths, the radius of curvature of the needle was found to approach the radius of curvature of the pre-curve. Pre-curved needles were found to display behaviors not seen with bevel-tipped needles, such as the insertion velocity influencing the path of the tip within the tissue and the ability to plastically deform the needle during steering. PMID:19963994

  3. Transducer Joint for Kidney-Stone Ultrasonics

    NASA Technical Reports Server (NTRS)

    Angulo, E. D.

    1983-01-01

    Ultrasonic therapy for kidney stones improved by new way of connecting wire-probe ultrasonic waveguide to transducer. Improved mounting allows joint to last long enough for effective treatment. Sheath and rubber dampers constrain lateral vibration of wire waveguide. Combination of V-shaped mounting groove, sheath, and rubber dampers increases life expectancy of wire 15 times or more.

  4. Broadband, High-Temperature Ultrasonic Transducer

    NASA Technical Reports Server (NTRS)

    Parker, F. Raymond; Winfree, William P.; Barrows, Danny A.

    1995-01-01

    Materials chosen for endurance at high temperatures and acoustic coupling and damping. Acoustic transducer designed to exhibit broad frequency response and to survive temperatures close to melting points of brazing alloys. Attached directly and continuously to hot object monitored ultrasonically: for example, it can be attached to relatively cool spot on workpiece during brazing for taking ultrasonic quality-control measurements.

  5. Improved convergence of electromechanical transducer element

    NASA Astrophysics Data System (ADS)

    Sattler, Robert; Wachutka, Gerhard

    2002-04-01

    Electrostatic attraction is a favored principle of actuation in MEMS (e.g. mirrors, relays, membrane devices). In this work we use an electrostatically actuated membrane as demonstrator. Physically based device models require the coupling of the electrostatic and the two domains. One way to reduce this expense consists in reduced order modeling by introducing a local approximation of the electric field using the Differential-Plate-Capacitor-Approximation (DPCA). This semi-analytical approximation can be directly (matrix coupled transducer element) or sequentially (load vector coupling) coupled with the mechanical solver. Both approaches yield results which agree well with those of coupled 3D-field solvers. It turns out that the transducer element converges much faster than the sequentially coupled relaxation scheme, as ong as the voltage is not close to the pull-in voltage. If this is the case then the transducer element has problems to find the equilibrium state at all. To avoid this difficulty we propose the use of a homotopy method to give the transducer element the same accuracy and robustness in the stable and the unstable regions of the operating area. The electrostatic charge and the electrostatic force turn out to be proper homotopy parameters for the given example.

  6. Non-bonded piezoelectric ultrasonic transducer

    DOEpatents

    Eoff, James M.

    1985-01-01

    A mechanically assembled non-bonded ultrasonic transducer includes a substrate, a piezoelectric film, a wetting agent, a thin metal electrode, and a lens held in intimate contact by a mechanical clamp. No epoxy or glue is used in the assembly of this device.

  7. Pressure compensated transducer system with constrained diaphragm

    NASA Astrophysics Data System (ADS)

    Percy, Joseph L.

    1992-08-01

    An acoustic source apparatus has an acoustic transducer that is enclosed in a substantially rigid and watertight enclosure to resist the pressure of water on the transducer and to seal the transducer from the water. The enclosure has an opening through which acoustic signals pass and over which is placed a resilient, expandable and substantially water-impermeable diaphragm. A net stiffens and strengthens the diaphragm as well as constrains the diaphragm from overexpansion or from migrating due to buoyancy forces. Pressurized gas, regulated at slightly above ambient pressure, is supplied to the enclosure and the diaphragm to compensate for underwater ambient pressures. Gas pressure regulated at above ambient pressure is used to selectively tune the pressure levels within the enclosure and diaphragm so that diaphragm resonance can be achieved. Controls are used to selectively fill, as well as vent the enclosure and diaphragm during system descent and ascent, respectively. A signal link is used to activate these controls and to provide the driving force for the acoustic transducer.

  8. Myocardium wall thickness transducer and measuring method

    NASA Technical Reports Server (NTRS)

    Feldstein, C.; Lewis, G. W.; Silver, R. H.; Culler, V. H. (Inventor)

    1976-01-01

    A miniature transducer for measuring changes of thickness of the myocardium is described. The device is easily implantable without traumatizing the subject, without affecting the normal muscle behavior, and is removable and implantable at a different muscle location. Operating features of the device are described.

  9. Unified Technical Concepts. Module 10: Transducers.

    ERIC Educational Resources Information Center

    Technical Education Research Center, Waco, TX.

    This concept module on transducers is one of thirteen modules that provide a flexible, laboratory-based physics instructional package designed to meet the specialized needs of students in two-year, postsecondary technical schools. Each of the thirteen concept modules discusses a single physics concept and how it is applied to each energy system.…

  10. Electropneumatic transducer automatically limits motor current

    NASA Technical Reports Server (NTRS)

    Lovitt, T. F.

    1966-01-01

    Pneumatic controller regulates the load on a centrifugal freon compressor in a water cooling system, thus limiting the current input to an electric motor driving it. An electromechanical transducer monitoring the motor input current sends out air signals which indicate changes in the current to the pneumatic controller.

  11. Instrument For Simulation Of Piezoelectric Transducers

    NASA Technical Reports Server (NTRS)

    Mcnichol, Randal S.

    1996-01-01

    Electronic instrument designed to simulate dynamic output of integrated-circuit piezoelectric acceleration or pressure transducer. Operates in conjunction with external signal-conditioning circuit, generating square-wave signal of known amplitude for use in calibrating signal-conditioning circuit. Instrument also useful as special-purpose square-wave generator in other applications.

  12. Piezoelectric and electrostrictive materials for transducer applications

    NASA Astrophysics Data System (ADS)

    Cross, L. E.; Newnham, R. E.; Barsch, G. R.; Biggers, J. V.

    1985-05-01

    This report covers work accomplished on the second year of contract No. N00014-82-K0339 for the study of Piezoelectric and Electrostrictive Materials for Transducer Applications. The work accomplished covers a rather wide range of topics and for convenience, it is divided into four major sub-topics: (1) composite materials, (2) electrostriction, (3) conventional piezoelectrics, and (4) preparative studies.

  13. Analysis of multifrequency langevin composite ultrasonic transducers.

    PubMed

    Lin, Shuyu

    2009-09-01

    The multimode coupled vibration of Langevin composite ultrasonic transducers with conical metal mass of large cross-section is analyzed. The coupled resonance and anti-resonance frequency equations are derived and the effective electromechanical coupling coefficient is analyzed. The effect of the geometrical dimensions on the resonance frequency, the anti-resonance frequency, and the effective electromechanical coupling coefficient is studied. It is illustrated that when the radial dimension is large compared with the longitudinal dimension, the vibration of the Langevin transducer becomes a multifrequency multimode coupled vibration. Numerical methods are used to simulate the coupled vibration; the simulated results are in good agreement with those from the analytical results. Some Langevin transducers of large cross-section are designed and manufactured and their resonance frequencies are measured. It can be seen that the resonance frequencies obtained from the coupled resonance frequency equations are in good agreement with the measured results. It is expected that by properly choosing the dimensions, multifrequency Langevin transducers can be designed and used in ultrasonic cleaning, ultrasonic sonochemistry, and other applications.

  14. Thermoacoustic power conversion using a piezoelectric transducer.

    PubMed

    Jensen, Carl; Raspet, Richard

    2010-07-01

    The predicted efficiency of a simple thermoacoustic waste heat power conversion device has been investigated as part of a collaborative effort combining a thermoacoustic engine with a piezoelectric transducer. Symko et al. [Microelectron. J. 35, 185-191 (2004)] at the University of Utah built high frequency demonstration engines for this application, and Lynn [ASMDC report, accession number ADA491030 (2008)] at the University of Washington designed and built a high efficiency piezoelectric unimorph transducer for electroacoustic conversion. The design presented in this paper is put forward to investigate the potential of a simple high frequency, air filled, standing wave thermoacoustic device to be competitive with other small generator technologies such as thermoelectric devices. The thermoacoustic generator is simulated using a low-amplitude approximation for thermoacoustics and the acoustic impedance of the transducer is modeled using an equivalent circuit model calculated from the transducer's mechanical and electrical properties. The calculations demonstrate that a device performance of around 10% of Carnot efficiency could be expected from the design which is competitive with currently available thermoelectric generators.

  15. Cosmic Needles versus Cosmic Microwave Background Radiation

    NASA Astrophysics Data System (ADS)

    Li, Aigen

    2003-02-01

    It has been suggested by a number of authors that the 2.7 K cosmic microwave background (CMB) radiation might have arisen from the radiation of ``Population III'' objects thermalized by conducting cosmic graphite/iron needle-shaped dust. Due to a lack of an accurate solution to the absorption properties of exceedingly elongated grains, in existing literature which studies the CMB thermalizing process they are generally modeled as (1) needle-like spheroids in terms of the Rayleigh approximation, (2) infinite cylinders, and (3) antennae. We show here that the Rayleigh approximation is not valid since the Rayleigh criterion is not satisfied for highly conducting needles. We also show that the available intergalactic iron dust, if modeled as infinite cylinders, is not sufficient to supply the required opacity at long wavelengths to obtain the observed isotropy and Planckian nature of the CMB. If appealing to the antenna theory, conducting iron needles with exceedingly large elongations ( >104) appear able to provide sufficient opacity to thermalize the CMB within the iron density limit. But the applicability of the antenna theory to exceedingly thin needles of nanometer/micrometer thickness has not yet been verified.

  16. Medically relevant ElectroNeedle technology development.

    SciTech Connect

    Schmidt, Carrie Frances; Thomas, Michael Loren; McClain, Jaime L.; Harper, Jason C.; Achyuthan, Komandoor E.; Ten Eyck, Gregory A.

    2008-11-01

    ElectroNeedles technology was developed as part of an earlier Grand Challenge effort on Bio-Micro Fuel Cell project. During this earlier work, the fabrication of the ElectroNeedles was accomplished along with proof-of-concept work on several electrochemically active analytes such as glucose, quinone and ferricyanide. Additionally, earlier work demonstrated technology potential in the field of immunosensors by specifically detecting Troponin, a cardiac biomarker. The current work focused upon fabrication process reproducibility of the ElectroNeedles and then using the devices to sensitively detect p-cresol, a biomarker for kidney failure or nephrotoxicity. Valuable lessons were learned regarding fabrication assurance and quality. The detection of p-cresol was accomplished by electrochemistry as well as using fluorescence to benchmark ElectroNeedles performance. Results from these studies will serve as a guide for the future fabrication processes involving ElectroNeedles as well as provide the groundwork necessary to expand technology applications. One paper has been accepted for publication acknowledging LDRD funding (K. E. Achyuthan et al, Comb. Chem. & HTS, 2008). We are exploring the scope for a second paper describing the applications potential of this technology.

  17. Optical Coherence Tomography in a Needle Format

    NASA Astrophysics Data System (ADS)

    Lorenser, Dirk; McLaughlin, Robert A.; Sampson, David D.

    In this chapter, we review the technology and applications of needle probes for optical coherence tomography (OCT). Needle probes are miniaturized fiber-optic probes that can be mounted inside hypodermic needles, allowing them to be inserted deep into the body during OCT imaging. This overcomes the very limited imaging depth of OCT of only 2-3 mm in biological tissue, enabling access to deep-tissue locations that are beyond the reach of free-space optical scan heads or catheters. This chapter provides an in-depth review of the current state-of-the art in needle probe technology, including optical design and fabrication, scan mechanisms (including three-dimensional scanning), and integration into OCT systems. It also provides an overview of emerging applications of this fascinating new imaging tool in areas such as cancer diagnosis, pulmonary imaging, imaging of the eye and imaging of the brain. Finally, two case studies are presented, illustrating needle-based OCT imaging in breast cancer and lungs.

  18. Evolvable Cryogenics (ECRYO) Pressure Transducer Calibration Test

    NASA Technical Reports Server (NTRS)

    Diaz, Carlos E., Jr.

    2015-01-01

    This paper provides a summary of the findings of recent activities conducted by Marshall Space Flight Center's (MSFC) In-Space Propulsion Branch and MSFC's Metrology and Calibration Lab to assess the performance of current "state of the art" pressure transducers for use in long duration storage and transfer of cryogenic propellants. A brief historical narrative in this paper describes the Evolvable Cryogenics program and the relevance of these activities to the program. This paper also provides a review of three separate test activities performed throughout this effort, including: (1) the calibration of several pressure transducer designs in a liquid nitrogen cryogenic environmental chamber, (2) the calibration of a pressure transducer in a liquid helium Dewar, and (3) the calibration of several pressure transducers at temperatures ranging from 20 to 70 degrees Kelvin (K) using a "cryostat" environmental chamber. These three separate test activities allowed for study of the sensors along a temperature range from 4 to 300 K. The combined data shows that both the slope and intercept of the sensor's calibration curve vary as a function of temperature. This homogeneous function is contrary to the linearly decreasing relationship assumed at the start of this investigation. Consequently, the data demonstrates the need for lookup tables to change the slope and intercept used by any data acquisition system. This ultimately would allow for more accurate pressure measurements at the desired temperature range. This paper concludes with a review of a request for information (RFI) survey conducted amongst different suppliers to determine the availability of current "state of the art" flight-qualified pressure transducers. The survey identifies requirements that are most difficult for the suppliers to meet, most notably the capability to validate the sensor's performance at temperatures below 70 K.

  19. Biasing of Capacitive Micromachined Ultrasonic Transducers.

    PubMed

    Caliano, Giosue; Matrone, Giulia; Savoia, Alessandro Stuart

    2017-02-01

    Capacitive micromachined ultrasonic transducers (CMUTs) represent an effective alternative to piezoelectric transducers for medical ultrasound imaging applications. They are microelectromechanical devices fabricated using silicon micromachining techniques, developed in the last two decades in many laboratories. The interest for this novel transducer technology relies on its full compatibility with standard integrated circuit technology that makes it possible to integrate on the same chip the transducers and the electronics, thus enabling the realization of extremely low-cost and high-performance devices, including both 1-D or 2-D arrays. Being capacitive transducers, CMUTs require a high bias voltage to be properly operated in pulse-echo imaging applications. The typical bias supply residual ripple of high-quality high-voltage (HV) generators is in the millivolt range, which is comparable with the amplitude of the received echo signals, and it is particularly difficult to minimize. The aim of this paper is to analyze the classical CMUT biasing circuits, highlighting the features of each one, and to propose two novel HV generator architectures optimized for CMUT biasing applications. The first circuit proposed is an ultralow-residual ripple (<5 [Formula: see text]) HV generator that uses an extremely stable sinusoidal power oscillator topology. The second circuit employs a commercially available integrated step-up converter characterized by a particularly efficient switching topology. The circuit is used to bias the CMUT by charging a buffer capacitor synchronously with the pulsing sequence, thus reducing the impact of the switching noise on the received echo signals. The small area of the circuit (about 1.5 cm(2)) makes it possible to generate the bias voltage inside the probe, very close to the CMUT, making the proposed solution attractive for portable applications. Measurements and experiments are shown to demonstrate the effectiveness of the new approaches

  20. Transducer technology transfer to bio-engineering applications. [aerospace stress transducer for heart function analysis

    NASA Technical Reports Server (NTRS)

    Duran, E. N.; Lewis, G. W.; Feldstein, C.; Corday, E.; Meerbaum, S.; Lang, T.

    1973-01-01

    The results of a technology transfer of a miniature unidirectional stress transducer, developed for experimental stress analysis in the aerospace field, to applications in bioengineering are reported. By modification of the basic design and innovations in attachment techniques, the transducer was successfully used in vivo on the myocardium of large dogs to record the change in contractile force due to coronary occlusion, reperfusion, and intervention.

  1. A high sensitivity sapphire transducer for vibration measurements

    SciTech Connect

    Peng, H.; Blair, D.G.; Ivanov, E.

    1994-12-31

    In this report we describe an interferometric Sapphire Dielectric Resonator (SDR) transducer which avoids the need for an ultra low noise oscillator. An initial performance of the transducer is presented.

  2. Perception and Action in Teleoperated Needle Insertion

    PubMed Central

    Nisky, Ilana; Pressman, Assaf; Pugh, Carla M.; Mussa-Ivaldi, Ferdinando A.; Karniel, Amir

    2015-01-01

    We studied the effect of delay on perception and action in contact with a force field that emulates elastic soft tissue with a rigid nonlinear boundary. Such field is similar to forces exerted on a needle during teleoperated needle insertion. We found that delay causes motor underestimation of the stiffness of this nonlinear soft tissue, without perceptual change. These experimental results are supported by simulation of a simplified mechanical model of the arm and neural controller, and a model for perception of stiffness, which is based on regression in the force-position space. In addition, we show that changing the gain of the teleoperation channel cancels the motor effect of delay without adding perceptual distortion. We conclude that it is possible to achieve perceptual and motor transparency in virtual one-dimensional remote needle insertion task. PMID:26379813

  3. Mechanics of Flexible Needles Robotically Steered through Soft Tissue

    PubMed Central

    Misra, S.; Reed, K. B.; Schafer, B. W.; Ramesh, K. T.; Okamura, A. M.

    2010-01-01

    The tip asymmetry of a bevel-tip needle results in the needle naturally bending when it is inserted into soft tissue. This enables robotic needle steering, which can be used in medical procedures to reach subsurface targets inaccessible by straight-line trajectories. However, accurate path planning and control of needle steering requires models of needle-tissue interaction. Previous kinematic models required empirical observations of each needle and tissue combination in order to fit model parameters. This study describes a mechanics-based model of robotic needle steering, which can be used to predict needle behavior and optimize system design based on fundamental mechanical and geometrical properties of the needle and tissue. We first present an analytical model for the loads developed at the tip, based on the geometry of the bevel edge and material properties of soft-tissue simulants (gels). We then present a mechanics-based model that calculates the deflection of a bevel-tipped needle inserted through a soft elastic medium. The model design is guided by microscopic observations of needle-gel interactions. The energy-based formulation incorporates tissue-specific parameters, and the geometry and material properties of the needle. Simulation results follow similar trends (deflection and radius of curvature) to those observed in experimental studies of robotic needle insertion. PMID:21170164

  4. Needle free injection technology: A complete insight

    PubMed Central

    Ravi, Ansh Dev; Sadhna, D; Nagpaal, D; Chawla, L

    2015-01-01

    Needle free injection technology (NFIT)is an extremely broad concept which include a wide range of drug delivery systems that drive drugs through the skin using any of the forces as Lorentz, Shock waves, pressure by gas or electrophoresis which propels the drug through the skin, virtually nullifying the use of hypodermic needle. This technology is not only touted to be beneficial for the pharma industry but developing world too find it highly useful in mass immunization programmes, bypassing the chances of needle stick injuries and avoiding other complications including those arising due to multiple use of single needle. The NFIT devices can be classified based on their working, type of load, mechanism of drug delivery and site of delivery. To administer a stable, safe and an effective dose through NFIT, the sterility, shelf life and viscosity of drug are the main components which should be taken care of. Technically superior needle-free injection systems are able to administer highly viscous drug products which cannot be administered by traditional needle and syringe systems, further adding to the usefulness of the technology. NFIT devices can be manufactured in a variety of ways; however the widely employed procedure to manufacture it is by injection molding technique. There are many variants of this technology which are being marketed, such as Bioject® ZetaJetTM, Vitajet 3, Tev-Tropin® and so on. Larger investment has been made in developing this technology with several devices already being available in the market post FDA clearance and a great market worldwide. PMID:26682189

  5. New needle-crystalline CR detector

    NASA Astrophysics Data System (ADS)

    Leblans, Paul J. R.; Struye, Luc; Willems, Peter

    2001-06-01

    The storage phosphor RbBr:Tl+ can be grown in needles via vacuum deposition. Thanks to reduced lateral light diffusion thick needle screens still offer acceptable resolution. Due to its low intrinsic X-ray absorption, however, a RbBr:Tl+ needle screen does not lead to a better absorption/resolution compromise than a BaFBr1-xIx:Eu2+ powder screen. CsBr:Eu2+ does combine high specific X-ray absorption and the possibility of needle growth. Its blue emission, peaking at 440 nm and near IR stimulation band, with maximum at 685 nm, make it well suited for use in CR systems. Sensitivity and sharpness of a 500 (mu) thick CsBr:Eu2+ needle screen were measured in a flying-spot scanner. The number of photostimulated light quanta per absorbed X-ray quantum is higher than for BaFBr1-xIx:Eu2+. At 70 kVp and 0.5 mm Cu filtration, equal sharpness is obtained for 85% vs. 46% X-ray absorption in BaFBr1-xIx:Eu2+ screens. DQE was measured at 2.5 (mu) Gy, 70 kVp, and 0.5 mm Cu filtration for a CsBr:Eu2+ needle screen in a flying-spot scanner. Up to 3 lp/mm, DQE was 2 times higher than for state-of-the-art CR systems and equal to the DQE claimed for flat panel DR systems, based on a-Si photodiodes combined with a CsI:Tl scintillator layer.

  6. Length mode piezoelectric ultrasonic transducer for inspection of solid objects

    NASA Technical Reports Server (NTRS)

    Thompson, R. B. (Inventor)

    1978-01-01

    The transducer is constructed from individual transducer elements arranged in an array and configured to exhibit a predominant, longitudinal mode transversely to the array. The elements are interconnected through thin flexible sheets. Each element is individually damped, and the transducer as a whole is electrically damped through resonance with the clamped capacitance and dissipation. Electrical control permits inphase operation of all transducer elements or control with preselected phase differences.

  7. A Thermal Analysis of High-Drive Ring Transducer Elements

    DTIC Science & Technology

    2005-08-15

    transducers . The principles developed in this report may be extended to other sonar-type transducers , such as Tonpilz and flextensional. The analytical results...August 2001, pp. 1469-1479. Rouquerol, E. V., "Calculation of the Heating of a Tonpilz -Type Transducer Due to the Dissipation from the Ceramic and the...NUWC-NPT Technical Report 11,467 15 August 2005 A Thermal Analysis of High-Drive Ring Transducer Elements Stephen C. Butler John B. Blottman III

  8. Syringe and Needle Size, Syringe Type, Vacuum Generation, and Needle Control in Aspiration Procedures

    SciTech Connect

    Haseler, Luke J.; Sibbitt, Randy R.; Sibbitt, Wilmer L.; Michael, Adrian A.; Gasparovic, Charles M.; Bankhurst, Arthur D.

    2011-06-15

    Purpose: Syringes are used for diagnostic fluid aspiration and fine-needle aspiration biopsy in interventional procedures. We determined the benefits, disadvantages, and patient safety implications of syringe and needle size on vacuum generation, hand force requirements, biopsy/fluid yield, and needle control during aspiration procedures. Materials and Methods: Different sizes (1, 3, 5, 10, and 20 ml) of the conventional syringe and aspirating mechanical safety syringe, the reciprocating procedure device, were studied. Twenty operators performed aspiration procedures with the following outcomes measured: (1) vacuum (torr), (2) time to vacuum (s), (3) hand force to generate vacuum (torr-cm{sup 2}), (4) operator difficulty during aspiration, (5) biopsy yield (mg), and (6) operator control of the needle tip position (mm). Results: Vacuum increased tissue biopsy yield at all needle diameters (P < 0.002). Twenty-milliliter syringes achieved a vacuum of -517 torr but required far more strength to aspirate, and resulted in significant loss of needle control (P < 0.002). The 10-ml syringe generated only 15% less vacuum (-435 torr) than the 20-ml device and required much less hand strength. The mechanical syringe generated identical vacuum at all syringe sizes with less hand force (P < 0.002) and provided significantly enhanced needle control (P < 0.002). Conclusions: To optimize patient safety and control of the needle, and to maximize fluid and tissue yield during aspiration procedures, a two-handed technique and the smallest syringe size adequate for the procedure should be used. If precise needle control or one-handed operation is required, a mechanical safety syringe should be considered.

  9. Signal processing schemes for optical voltage transducer

    NASA Astrophysics Data System (ADS)

    Chen, Jinling; Xie, Delin; Chen, Hongbin; Xie, Latang; Song, Jianhe; Luo, Xiaoni

    2006-02-01

    This paper describes an optical voltage transducer(OVT) for a 35kV system based on Pockels effect in a BGO(Bi 4Ge 3O 12) crystal. OVT used to measure the voltage of power are superior to conventional electromagnet-induced voltage transducer in many aspects, thus it has great potential to applications. It has some advantages. These advantages are: 1)Optics provides total galvanic separation between the measuring point at high voltage (HV) potential and the measuring equipment at ground potential. 2)Transmission of measuring signals in optical fibers is immune to induced electromagnetic noise even in EMI-environment of switchyards and other high voltage installations. 3)Optics and especially optical fibers make the insulation costs independent of voltage levels thus giving an economical advantage at voltage levels above 100kV. 4)The use of optics is expected to reduce the weight of the transducers. 5)Optical transducers are expected to have a large bandwidth than conventional transducers. 6)The output-signals from an optical transducer are easily interfaced with computers and electronically operated equipment such as digital relays. New techniques developed in electronics and optical field including fiber optic technology bring new contributions to the measurement of voltage and electric field. A Pockels voltage sensor has been widely introduced to electrical power transmission and distribution systems and some advantage of the optical voltage measuring techniques are reported. In this paper, a brief summary of electro-optic effects and the principle of OVT is proposed. The signal processing schemes of different optical path and features are analyzed. The basic principle of OVT is to modulate the irradiance of the light-directed to OVT by an optical fiber-according to the potential difference between the HV-line and the ground potential. The modulation of the light is accomplished by placing a material-that has an optical property (the birefringence), which is

  10. 21 CFR 868.2900 - Gas pressure transducer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Gas pressure transducer. 868.2900 Section 868.2900...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2900 Gas pressure transducer. (a) Identification. A gas pressure transducer is a device intended for medical purposes that is used to convert...

  11. 21 CFR 868.2885 - Gas flow transducer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Gas flow transducer. 868.2885 Section 868.2885...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2885 Gas flow transducer. (a) Identification. A gas flow transducer is a device intended for medical purposes that is used to convert gas...

  12. 21 CFR 868.2885 - Gas flow transducer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Gas flow transducer. 868.2885 Section 868.2885...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2885 Gas flow transducer. (a) Identification. A gas flow transducer is a device intended for medical purposes that is used to convert gas...

  13. 21 CFR 870.2060 - Transducer signal amplifier and conditioner.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Transducer signal amplifier and conditioner. 870.2060 Section 870.2060 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... Transducer signal amplifier and conditioner. (a) Identification. A transducer signal amplifier...

  14. 21 CFR 870.2060 - Transducer signal amplifier and conditioner.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Transducer signal amplifier and conditioner. 870.2060 Section 870.2060 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... Transducer signal amplifier and conditioner. (a) Identification. A transducer signal amplifier...

  15. 21 CFR 870.2060 - Transducer signal amplifier and conditioner.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Transducer signal amplifier and conditioner. 870.2060 Section 870.2060 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... Transducer signal amplifier and conditioner. (a) Identification. A transducer signal amplifier...

  16. 21 CFR 870.2060 - Transducer signal amplifier and conditioner.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Transducer signal amplifier and conditioner. 870.2060 Section 870.2060 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... Transducer signal amplifier and conditioner. (a) Identification. A transducer signal amplifier...

  17. 21 CFR 870.2060 - Transducer signal amplifier and conditioner.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Transducer signal amplifier and conditioner. 870.2060 Section 870.2060 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN... Transducer signal amplifier and conditioner. (a) Identification. A transducer signal amplifier...

  18. 21 CFR 870.2850 - Extravascular blood pressure transducer.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Extravascular blood pressure transducer. 870.2850... blood pressure transducer. (a) Identification. An extravascular blood pressure transducer is a device used to measure blood pressure by changes in the mechanical or electrical properties of the device....

  19. 21 CFR 870.2850 - Extravascular blood pressure transducer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Extravascular blood pressure transducer. 870.2850... blood pressure transducer. (a) Identification. An extravascular blood pressure transducer is a device used to measure blood pressure by changes in the mechanical or electrical properties of the device....

  20. 21 CFR 870.2870 - Catheter tip pressure transducer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Catheter tip pressure transducer. 870.2870 Section... pressure transducer. (a) Identification. A catheter tip pressure transducer is a device incorporated into... change in relation to changes in blood pressure. These changes are transmitted to accessory equipment...

  1. 21 CFR 868.2875 - Differential pressure transducer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Differential pressure transducer. 868.2875 Section... (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2875 Differential pressure transducer. (a) Identification. A differential pressure transducer is a two-chambered device intended...

  2. 21 CFR 890.1615 - Miniature pressure transducer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Miniature pressure transducer. 890.1615 Section... Miniature pressure transducer. (a) Identification. A miniature pressure transducer is a device intended for medical purposes to measure the pressure between a device and soft tissue by converting mechanical...

  3. 21 CFR 868.2900 - Gas pressure transducer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Gas pressure transducer. 868.2900 Section 868.2900...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2900 Gas pressure transducer. (a) Identification. A gas pressure transducer is a device intended for medical purposes that is used to convert...

  4. 21 CFR 870.2850 - Extravascular blood pressure transducer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Extravascular blood pressure transducer. 870.2850... blood pressure transducer. (a) Identification. An extravascular blood pressure transducer is a device used to measure blood pressure by changes in the mechanical or electrical properties of the device....

  5. 21 CFR 868.2900 - Gas pressure transducer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Gas pressure transducer. 868.2900 Section 868.2900...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2900 Gas pressure transducer. (a) Identification. A gas pressure transducer is a device intended for medical purposes that is used to convert...

  6. 21 CFR 870.2870 - Catheter tip pressure transducer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Catheter tip pressure transducer. 870.2870 Section... pressure transducer. (a) Identification. A catheter tip pressure transducer is a device incorporated into... change in relation to changes in blood pressure. These changes are transmitted to accessory equipment...

  7. 21 CFR 890.1615 - Miniature pressure transducer.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Miniature pressure transducer. 890.1615 Section... Miniature pressure transducer. (a) Identification. A miniature pressure transducer is a device intended for medical purposes to measure the pressure between a device and soft tissue by converting mechanical...

  8. 21 CFR 870.2870 - Catheter tip pressure transducer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Catheter tip pressure transducer. 870.2870 Section... pressure transducer. (a) Identification. A catheter tip pressure transducer is a device incorporated into... change in relation to changes in blood pressure. These changes are transmitted to accessory equipment...

  9. 21 CFR 868.2900 - Gas pressure transducer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Gas pressure transducer. 868.2900 Section 868.2900...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2900 Gas pressure transducer. (a) Identification. A gas pressure transducer is a device intended for medical purposes that is used to convert...

  10. 21 CFR 870.2850 - Extravascular blood pressure transducer.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Extravascular blood pressure transducer. 870.2850... blood pressure transducer. (a) Identification. An extravascular blood pressure transducer is a device used to measure blood pressure by changes in the mechanical or electrical properties of the device....

  11. 21 CFR 868.2900 - Gas pressure transducer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Gas pressure transducer. 868.2900 Section 868.2900...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2900 Gas pressure transducer. (a) Identification. A gas pressure transducer is a device intended for medical purposes that is used to convert...

  12. 21 CFR 870.2850 - Extravascular blood pressure transducer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Extravascular blood pressure transducer. 870.2850... blood pressure transducer. (a) Identification. An extravascular blood pressure transducer is a device used to measure blood pressure by changes in the mechanical or electrical properties of the device....

  13. 21 CFR 868.2885 - Gas flow transducer.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Gas flow transducer. 868.2885 Section 868.2885...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2885 Gas flow transducer. (a) Identification. A gas flow transducer is a device intended for medical purposes that is used to convert gas...

  14. New developments in ultrasonic transducers and transducer systems; Proceedings of the Meeting, San Diego, CA, July 21, 22, 1992

    NASA Astrophysics Data System (ADS)

    Lizzi, Frederic L.

    Attention is given to advances in materials and modeling transducer performance, the means to control ultrasonic beams and to measure their properties, the variety of array configurations, and novel transducer configurations and design considerations. Emphasis is placed on new developments in piezoelectric polymer ultrasound transducers and transducer systems; micromachined acoustic matching layers; a dual frequency piezoelectric transducer for medical applications; modeling refraction and attenuation effects in invasive ultrasound probes; design and evaluation of ultrasonic arrays using 1-3 connectivity composites; artifact reduction through the use of concave linear arrays; real-time 3D ultrasound imaging with a 1D fan-beam transducer array; some conceptual approaches to innovative medical ultrasound transducers; and enhanced bandwidth ultrasound transducers with multiple piezoelectric polymer layers. (No individual items are abstracted in this volume)

  15. Simple and sensitive strain gauge displacement transducer

    NASA Astrophysics Data System (ADS)

    Ramana, Y. V.; Sarma, L. P.

    1981-09-01

    We describe a simple and sensitive strain gauge displacement transducer. It is based on the linear movement of a shaft (with two cantilevers and four strain gauges) in a tapered chamber, resulting in a change in resistance proportional to the cantilever deformation. The transducer with its Wheatstone full bridge configuration is calibrated against a mechanical dial indicator of 0.002 mm accuracy for both ac and dc voltage excitations. Its output is linear for measurements of full range displacement up to 25 mm. It has a sensitivity of ±0.0082 mm for ac excitation with a strain indicator whose resolution is ±1 μɛ. It has a dc full range sensitivity of 1.5 mV/V for excitation levels up to 5 V. It can have varied field and laboratory applications wherever displacements are precisely read, recorded, or monitored.

  16. Electromechanical transducer for acoustic telemetry system

    DOEpatents

    Drumheller, D.S.

    1993-06-22

    An improved electromechanical transducer is provided for use in an acoustic telemetry system. The transducer of this invention comprises a stack of ferroelectric ceramic disks interleaved with a plurality of spaced electrodes which are used to electrically pole the ceramic disks. The ceramic stack is housed in a metal tubular drill collar segment. The electrodes are preferably alternatively connected to ground potential and driving potential. This alternating connection of electrodes to ground and driving potential subjects each disk to an equal electric field; and the direction of the field alternates to match the alternating direction of polarization of the ceramic disks. Preferably, a thin metal foil is sandwiched between electrodes to facilitate the electrical connection. Alternatively, a thicker metal spacer plate is selectively used in place of the metal foil in order to promote thermal cooling of the ceramic stack.

  17. New piezoelectric transducers for therapeutic ultrasound.

    PubMed

    Chapelon, J Y; Cathignol, D; Cain, C; Ebbini, E; Kluiwstra, J U; Sapozhnikov, O A; Fleury, G; Berriet, R; Chupin, L; Guey, J L

    2000-01-01

    Therapeutic ultrasound (US) has been of increasing interest during the past few years. However, the development of this technique depends on the availability of high-performance transducers. These transducers have to be optimised for focusing and steering high-power ultrasonic energy within the target volume. Recently developed high-power 1-3 piezocomposite materials bring to therapeutic US the exceptional electroacoustical properties of piezocomposite technology: these are high efficiency, large bandwidth, predictable beam pattern, more flexibility in terms of shaping and definition of sampling in annular arrays, linear arrays or matrix arrays. The construction and evaluation of several prototypes illustrates the benefit of this new approach that opens the way to further progress in therapeutic US.

  18. Piezoelectric radiofrequency transducers as passive buried sensors

    NASA Astrophysics Data System (ADS)

    Rétornaz, T.; Friedt, J.-M.; Alzuaga, S.; Baron, T.; Lebrasseur, É.; Martin, G.; Laroche, T.; Ballandras, S.; Griselin, M.; Simonnet, J.-P.

    2012-09-01

    We demonstrate that single-piezoelectric substrate-based acoustic transducers act as ideal sensors for probing with various RADAR strategies. Because these sensors are intrinsically passive devices working in the radiofrequency range, they exhibit improved interrogation range and robustness with respect to silicon-based radio frequency identification tags. Both wideband (acoustic delay lines) and narrowband (acoustic resonators) transducers are shown to be compatible with pulse-mode and frequency-modulated continuous-wave RADAR strategies, respectively. We particularly focus on the ground-penetrating RADAR (GPR) application in which the lack of local energy source makes these sensors suitable candidates for buried applications in roads, building or civil engineering monitoring. A novel acoustic sensor concept - high-overtone bulk acoustic resonator - is especially suited as sensor interrogated by a wide range of antenna set, as demonstrated with GPR units working in the 100 and 200 MHz range.

  19. Electromechanical transducer for acoustic telemetry system

    DOEpatents

    Drumheller, Douglas S.

    1993-01-01

    An improved electromechanical transducer is provided for use in an acoustic telemetry system. The transducer of this invention comprises a stack of ferroelectric ceramic disks interleaved with a plurality of spaced electrodes which are used to electrically pole the ceramic disks. The ceramic stack is housed in a metal tubular drill collar segment. The electrodes are preferably alternatively connected to ground potential and driving potential. This alternating connection of electrodes to ground and driving potential subjects each disk to an equal electric field; and the direction of the field alternates to match the alternating direction of polarization of the ceramic disks. Preferably, a thin metal foil is sandwiched between electrodes to facilitate the electrical connection. Alternatively, a thicker metal spacer plate is selectively used in place of the metal foil in order to promote thermal cooling of the ceramic stack.

  20. Bonded ultrasonic transducer and method for making

    DOEpatents

    Dixon, Raymond D.; Roe, Lawrence H.; Migliori, Albert

    1995-01-01

    An ultrasonic transducer is formed as a diffusion bonded assembly of piezoelectric crystal, backing material, and, optionally, a ceramic wear surface. The mating surfaces of each component are silver films that are diffusion bonded together under the application of pressure and heat. Each mating surface may also be coated with a reactive metal, such as hafnium, to increase the adhesion of the silver films to the component surfaces. Only thin silver films are deposited, e.g., a thickness of about 0.00635 mm, to form a substantially non-compliant bond between surfaces. The resulting transducer assembly is substantially free of self-resonances over normal operating ranges for taking resonant ultrasound measurements.

  1. Bonded ultrasonic transducer and method for making

    DOEpatents

    Dixon, R.D.; Roe, L.H.; Migliori, A.

    1995-11-14

    An ultrasonic transducer is formed as a diffusion bonded assembly of piezoelectric crystal, backing material, and, optionally, a ceramic wear surface. The mating surfaces of each component are silver films that are diffusion bonded together under the application of pressure and heat. Each mating surface may also be coated with a reactive metal, such as hafnium, to increase the adhesion of the silver films to the component surfaces. Only thin silver films are deposited, e.g., a thickness of about 0.00635 mm, to form a substantially non-compliant bond between surfaces. The resulting transducer assembly is substantially free of self-resonances over normal operating ranges for taking resonant ultrasound measurements. 12 figs.

  2. Acoustic transducer apparatus with reduced thermal conduction

    NASA Technical Reports Server (NTRS)

    Lierke, Ernst G. (Inventor); Leung, Emily W. (Inventor); Bhat, Balakrishna T. (Inventor)

    1990-01-01

    A horn is described for transmitting sound from a transducer to a heated chamber containing an object which is levitated by acoustic energy while it is heated to a molten state, which minimizes heat transfer to thereby minimize heating of the transducer, minimize temperature variation in the chamber, and minimize loss of heat from the chamber. The forward portion of the horn, which is the portion closest to the chamber, has holes that reduce its cross-sectional area to minimize the conduction of heat along the length of the horn, with the entire front portion of the horn being rigid and having an even front face to efficiently transfer high frequency acoustic energy to fluid in the chamber. In one arrangement, the horn has numerous rows of holes extending perpendicular to the length of horn, with alternate rows extending perpendicular to one another to form a sinuous path for the conduction of heat along the length of the horn.

  3. Gel-Filled Holders For Ultrasonic Transducers

    NASA Technical Reports Server (NTRS)

    Companion, John A.

    1992-01-01

    In new technique, ultrasonic transducer embedded in rubbery, castable, low-loss gel to enable transducer to "look" into surface of test object or human body at any desired angle. Composed of solution of water and ethylene glycol in collagen matrix. Provides total contact of water bath, also used on bodies or objects too large for water baths, even if moving. Also provides look angles of poly(methyl methacrylate) angle block with potential of reduced acoustic impedance and refraction. Custom-tailored to task at hand, and gel sufficiently inexpensive to be discarded upon completion. Easy to couple ultrasound in and out of gel, minimizing losses and artifacts of other types of standoffs employed in ultrasonic testing.

  4. Improvements to the Processing and Characterization of Needled Composite Laminates

    DTIC Science & Technology

    2014-01-01

    that mode I fracture toughness improves up to 270% compared to non- needled baseline material. In-plane compressive strength of needled material... fracture toughness improves up to 270% compared to non-needled baseline material. In-plane compressive strength of needled material improves by up to 475...shear (DLS) tests are performed to assess improvements in mode-I fracture toughness and shear strength. Tension and compression tests are

  5. Needle Path Planning for Autonomous Robotic Surgical Suturing

    PubMed Central

    Jackson, Russell C.; Çavuşoğlu, M. Cenk

    2013-01-01

    This paper develops a path plan for suture needles used with solid tissue volumes in endoscopic surgery. The path trajectory is based on the best practices that are used by surgeons. The path attempts to minimize the interaction forces between the tissue and the needle. Using surgical guides as a basis, two different techniques for driving a suture needle are developed. The two techniques are compared in hardware experiments by robotically driving the suture needle using both of the motion plans. PMID:24683500

  6. Needle Path Planning for Autonomous Robotic Surgical Suturing.

    PubMed

    Jackson, Russell C; Cavuşoğlu, M Cenk

    2013-12-31

    This paper develops a path plan for suture needles used with solid tissue volumes in endoscopic surgery. The path trajectory is based on the best practices that are used by surgeons. The path attempts to minimize the interaction forces between the tissue and the needle. Using surgical guides as a basis, two different techniques for driving a suture needle are developed. The two techniques are compared in hardware experiments by robotically driving the suture needle using both of the motion plans.

  7. Sonar Transducer Reliability Improvement Program (STRIP)

    DTIC Science & Technology

    1981-01-01

    and wet all of the surfaces of the transducer. This greatly conplicates bonding the components together. Polyalkylene glycol (PAG) ha:; the...ether of polypropylene oxide ; molecular weight, 600 g/mole with small amounts of the anticxidant dodecyl succinic anhydride REMARKS: ADVANTAGES - Cheap...STABILITY: OXIDATION - Good HYDROLYSIS - Very Good "[63] OTHERS: TOXICITY - .ontoxtc, no e/e or skin irritetion- *[631 EASE OF CLEAJP - Have re.dily

  8. Flutter spectral measurements using stationary pressure transducers

    NASA Technical Reports Server (NTRS)

    Kurkov, A. P.

    1980-01-01

    Engine-order sampling was used to eliminate the integral harmonics from the flutter spectra corresponding to a case-mounted static pressure transducer. Using the optical displacement data, it was demonstrated that the blade-order sampling of pressure data may yield erroneous results due to the interference caused by blade vibration. Two methods are presented which effectively eliminate this interference yielding the blade-pressure-difference spectra. The phase difference between the differential-pressure and the displacement spectra was evaluated.

  9. Low Voltage Piezoelectric Composite for Transducer Applications

    DTIC Science & Technology

    2005-02-25

    Pillars 10 are supported in 10 panel 20 by insulating material 18. Insulating material 18 can 11 be a dielectric polymer matrix or an elastomeric ...Additionally, the field. 22 impressed on the surface doesn’t couple completely to the 23 internal volume of the active material . 9 1 In view of the above...The active layer of the transducer is either lead 16 zirconium-titanate or lead magnesium-niobate. This material is 17 incorporated in a polymer

  10. Sonar Transducer Reliability Improvement Program (STRIP).

    DTIC Science & Technology

    1981-04-01

    surfaces of PZT ceramic. The ceramic surface tends to be the weakest part of the insulation system of a sonar transducer. The highest typical electrical...comparable value obtained with uncoated ceramic. Also, the breakdown voltage on the surface ( flashover ) was increased only a small amount, typically less...coating/ surface interface, and some were combinations. A coating material often touted as exceptionally 3ood is Parylene, which is vacuum deposited

  11. Robust Acoustic Transducers for Bubble Chambers

    NASA Astrophysics Data System (ADS)

    Wells, Jonathan

    2015-04-01

    The PICO collaboration utilizes bubble chambers filled with various superheated liquids as targets for dark matter. Acoustic sensors have proved able to distinguish nuclear recoils from radioactive background on an event-by-event basis. We have recently produced a more robust transducer which should be able to operate for years, rather than months, in the challenging environment of a heated high pressure hydraulic fluid outside these chambers. Indiana University South Bend.

  12. Sonar Transducer Reliability Improvement Program FY80.

    DTIC Science & Technology

    1980-01-01

    band Threshold - less than ±2 dB variation from the specified value over operational frequency band The Sonar Transducer Reliability Improvement...were Qetiker preformed clamps, Band -It preformed clamps, and Band -It Scru-Loct retrofittable clamps. *TASK 5: Manufacture Instrumented Connectors Under...cycle 6 PRE-kORM 10 PU-U Cable bond failure, Remove from test after DSS-3 under gap in clamp cycle 5 OETIKER 11 N-G " ring leakage was Removed from

  13. Wheel Force Transducer Research and Development

    DTIC Science & Technology

    2012-03-02

    develop, validate and calibrate cost effective field test equipment for measuring tire characteristics on vehicles whilst driving off-road. The proposed... field test equipment for measuring tire characteristics on vehicles whilst driving off-road. The proposed wheel force transducer is an important...of simulating off-road terrain under laboratory conditions, field test equipment, that can determine tire characteristics on vehicles whilst driving

  14. Updated Results of Ultrasonic Transducer Irradiation Test

    SciTech Connect

    Daw, Joshua; Palmer, Joe; Ramuhalli, Pradeep; Keller, Paul; Montgomery, Robert; Chien, Hual-Te; Tittmann, Bernhard; Reinhardt, Brian; Kohse, Gordon; Rempe, Joy; Villard, J.F.

    2015-07-01

    Ultrasonic technologies offer the potential for high accuracy and resolution in-pile measurement of a range of parameters, including geometry changes, temperature, crack initiation and growth, gas pressure and composition, and microstructural changes. Many Department of Energy-Office of Nuclear Energy (DOE-NE) programs are exploring the use of ultrasonic technologies to provide enhanced sensors for in-pile instrumentation during irradiation testing. For example, the ability of small diameter ultrasonic thermometers (UTs) to provide a temperature profile in candidate metallic and oxide fuel would provide much needed data for validating new fuel performance models. These efforts are limited by the lack of identified ultrasonic transducer materials capable of long term performance under irradiation test conditions. To address this need, the Pennsylvania State University (PSU) was awarded an Advanced Test Reactor National Scientific User Facility (ATR NSUF) project to evaluate the performance of promising magnetostrictive and piezoelectric transducers in the Massachusetts Institute of Technology Research Reactor (MITR) up to a fast fluence of at least 10{sup 21} n/cm{sup 2}. A multi-National Laboratory collaboration funded by the Nuclear Energy Enabling Technologies Advanced Sensors and Instrumentation (NEET-ASI) program also provided initial support for this effort. This irradiation, which started in February 2014, is an instrumented lead test and real-time transducer performance data are collected along with temperature and neutron and gamma flux data. The irradiation is ongoing and will continue to approximately mid-2015. To date, very encouraging results have been attained as several transducers continue to operate under irradiation. (authors)

  15. Ultrasonic transducer with Gaussian radial pressure distribution

    NASA Technical Reports Server (NTRS)

    Claus, R. O.; Zerwekh, P. S. (Inventor)

    1984-01-01

    An ultrasonic transducer that produces an output that is a symmetrical function comprises a piezoelectric crystal with several concentric ring electrodes on one side of the crystal. A resistor network applies different amplitudes of an ac source to each of the several electrodes. A plot of the different amplitudes from the outermost electrode to the innermost electrode is the first half of a Gaussian function. Consequently, the output of the crystal from the side opposite the electrodes has a Gaussian profile.

  16. Piezoelectric and Electrostrictive Materials for Transducer Applications.

    DTIC Science & Technology

    1985-05-01

    University Park, PA 16802 USA (Received December 15, 1984) A phenomenological theory., based on the Landau -Ginsburg-Devonshire formalism is developed to...transducers was difficult. The electrical loading effects were corrected by using back-to- back zener diodes, inserted between the amplifier and the...product. The highest pulse-echo amplitude (2.25 V) with the 4 U back-to-back zener diode termination came from the composite sample with 20% PZT rods of

  17. "Zero-Mass" Noninvasive Pressure Transducers

    NASA Technical Reports Server (NTRS)

    Hartley, Frank T.

    2009-01-01

    Extremely lightweight, compact, noninvasive, rugged, relatively inexpensive strain-gauge transducers have been developed for use in measuring pressures of fluids in tubes. These gauges were originally intended for measuring pressures of spacecraft-propulsion fluids, but they are also attractive for use in numerous terrestrial applications especially those involving fluids that are extremely chemically reactive, fluids that must be isolated for hygienic purposes, fluids that must be allowed to flow without obstruction, and fluid-containing tubes exposed to severe environments. A basic pressure transducer of this type comprises one or more pair(s) of thin-film strain gauges integral with a tube that contains the fluid of interest. Following established strain-gauge practice, the gauges in each pair are connected into opposite arms of a Wheatstone bridge (see figure). Typically, each pressure transducer includes one pair (the active pair) of strain gauges for measuring the hoop stress proportional to the pressure of the fluid in the tube and another pair (the dummy pair) of strain gauges that are nominally unstrained: The dummy gauges are mounted on a substrate that is made of the same material as that of the tube. The substrate is welded to the tube at only one spot so that stresses and strains are not coupled from the tube into the substrate. The dummy strain gauges measure neutral strains (basically, strains associated with thermal expansion), so that the neutral-strain contribution can be subtracted out of the final gauge reading.

  18. Cross-fiber Bragg grating transducer

    NASA Technical Reports Server (NTRS)

    Albin, Sacharia (Inventor); Zheng, Jianli (Inventor); Lavarias, Arnel (Inventor)

    2000-01-01

    A transducer has been invented that uses specially-oriented gratings in waveguide a manner that allows the simultaneous measurement of physical phenomena (such as shear force, strain and temperature) in a single sensing element. The invention has a highly sensitive, linear response and also has directional sensitivity with regard to strain. The transducer has a waveguide with a longitudinal axis as well as two Bragg gratings. The transducer has a first Bragg grating associated with the waveguide that has an angular orientation .theta..sub.a relative to a perpendicular to the longitudinal axis such that 0.degree.<.theta..sub.a <.theta..sub.max. The second Bragg grating is associated with the waveguide in such a way that the angular orientation .theta..sub.b of the grating relative to a perpendicular to the longitudinal axis is (360.degree.-.theta..sub.max)<.theta..sub.b <360.degree.. The first Bragg grating can have a periodicity .LAMBDA..sub.a and the second Bragg grating can have a periodicity .LAMBDA..sub.b such that the periodicity .LAMBDA..sub.a of the first Bragg grating does not equal the periodicity .LAMBDA..sub.b of the second Bragg grating. The angle of the gratings can be such that .theta..sub.a =360.degree.-.theta..sub.b. The waveguide can assume a variety of configurations, including an optical fiber, a rectangular waveguide and a planar waveguide. The waveguide can be fabricated of a variety of materials, including silica and polymer material.

  19. Simultaneous muscle force and displacement transducer

    NASA Technical Reports Server (NTRS)

    Feldstein, C.; Lewis, G. W.; Culler, V. H. (Inventor)

    1980-01-01

    A myocardial transducer for simultaneously measuring force and displacement within a very small area of myocardium is disclosed. The transducer comprised of an elongated body forked at one end to form an inverted Y shaped beam with each branch of the beam constituting a low compliant tine for penetrating the myocardium to a predetermined depth. Bonded to one of the low compliance tines is a small piezoresistive element for converting a force acting on the beam into an electrical signal. A third high compliant tine of the transducer, which measures displacement of the myocardium in a direction in line with the two low compliant tines, is of a length that just pierces the surface membrane. A small piezoresistive element is bonded to the third tine at its upper end where its bending is greatest. Displacement of the myocardium causes a deformation in curvature of the third tine, and the second small piezoresistive element bonded to the surface of its curved end converts its deformation into an electrical signal.

  20. Evaluation of Robotic Needle Steering in ex vivo Tissue

    PubMed Central

    Majewicz, Ann; Wedlick, Thomas R.; Reed, Kyle B.; Okamura, Allison M.

    2010-01-01

    Insertion velocity, tip asymmetry, and shaft diameter may influence steerable needle insertion paths in soft tissue. In this paper we examine the effects of these variables on needle paths in ex vivo goat liver, and demonstrate practical applications of robotic needle steering for ablation, biopsy, and brachytherapy. All experiments were performed using a new portable needle steering robot that steers asymmetric-tip needles under fluoroscopic imaging. For bevel-tip needles, we found that larger diameter needles resulted in less curvature, i.e. less steerability, confirming previous experiments in artificial tissue. The needles steered with radii of curvature ranging from 3:4 cm (for the most steerable pre-bent needle) to 2:97m (for the least steerable bevel needle). Pre-bend angle significantly affected needle curvature, but bevel angle did not. We hypothesize that biological tissue characteristics such as inhomogeneity and viscoelasticity significantly increase path variability. These results underscore the need for closed-loop image guidance for needle steering in biological tissues with complex internal structure. PMID:21339851

  1. Modeling and Control of Needles with Torsional Friction

    PubMed Central

    Reed, Kyle B.; Okamura, Allison M.; Cowan, Noah J.

    2010-01-01

    A flexible needle can be accurately steered by robotically controlling the bevel tip orientation as the needle is inserted into tissue. Friction between the long, flexible needle shaft and the tissue can cause a significant discrepancy between the orientation of the needle tip and the orientation of the base where the needle angle is controlled. Our experiments show that several common phantom tissues used in needle steering experiments impart substantial friction forces to the needle shaft, resulting in a lag of over 45° for a 10 cm insertion depth in some phantoms; clinical studies report torques large enough to cause similar errors during needle insertions. Such angle discrepancies will result in poor performance or failure of path planners and image-guided controllers, since the needles used in percutaneous procedures are too small for state-of-the-art imaging to accurately measure the tip angle. To compensate for the angle discrepancy, we develop an estimator using a mechanics-based model of the rotational dynamics of a needle being inserted into tissue. Compared to controllers that assume a rigid needle in a frictionless environment, our estimator-based controller improves the tip angle convergence time by nearly 50% and reduces the path deviation of the needle by 70%. PMID:19695979

  2. The Double-Needle Felling Machine. Module 17.

    ERIC Educational Resources Information Center

    South Carolina State Dept. of Education, Columbia. Office of Vocational Education.

    This module on the double-needle felling machine, one in a series dealing with industrial sewing machines, their attachments, and operation, covers two topics: performing special operations on the double-needle felling machine (straight seams) and performing special operations on the double-needle felling machine (curved flat-felled seams). For…

  3. 21 CFR 868.5150 - Anesthesia conduction needle.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Anesthesia conduction needle. 868.5150 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5150 Anesthesia conduction needle. (a) Identification. An anesthesia conduction needle is a device used to inject local anesthetics into a patient...

  4. 21 CFR 868.5150 - Anesthesia conduction needle.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Anesthesia conduction needle. 868.5150 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5150 Anesthesia conduction needle. (a) Identification. An anesthesia conduction needle is a device used to inject local anesthetics into a patient...

  5. 21 CFR 884.6100 - Assisted reproduction needles.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Assisted reproduction needles. 884.6100 Section... (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Assisted Reproduction Devices § 884.6100 Assisted reproduction needles. (a) Identification. Assisted reproduction needles are devices used in...

  6. 21 CFR 884.6100 - Assisted reproduction needles.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Assisted reproduction needles. 884.6100 Section... (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Assisted Reproduction Devices § 884.6100 Assisted reproduction needles. (a) Identification. Assisted reproduction needles are devices used in...

  7. 21 CFR 884.6100 - Assisted reproduction needles.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Assisted reproduction needles. 884.6100 Section... (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Assisted Reproduction Devices § 884.6100 Assisted reproduction needles. (a) Identification. Assisted reproduction needles are devices used in...

  8. 21 CFR 884.6100 - Assisted reproduction needles.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Assisted reproduction needles. 884.6100 Section... (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Assisted Reproduction Devices § 884.6100 Assisted reproduction needles. (a) Identification. Assisted reproduction needles are devices used in...

  9. 21 CFR 884.6100 - Assisted reproduction needles.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Assisted reproduction needles. 884.6100 Section... (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Assisted Reproduction Devices § 884.6100 Assisted reproduction needles. (a) Identification. Assisted reproduction needles are devices used in...

  10. 21 CFR 868.5150 - Anesthesia conduction needle.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Anesthesia conduction needle. 868.5150 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5150 Anesthesia conduction needle. (a) Identification. An anesthesia conduction needle is a device used to inject local anesthetics into a patient...

  11. 21 CFR 868.5150 - Anesthesia conduction needle.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Anesthesia conduction needle. 868.5150 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5150 Anesthesia conduction needle. (a) Identification. An anesthesia conduction needle is a device used to inject local anesthetics into a patient...

  12. 21 CFR 868.5150 - Anesthesia conduction needle.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Anesthesia conduction needle. 868.5150 Section 868...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Therapeutic Devices § 868.5150 Anesthesia conduction needle. (a) Identification. An anesthesia conduction needle is a device used to inject local anesthetics into a patient...

  13. Language of Transducer Manipulation: Codifying Terms for Effective Teaching.

    PubMed

    Bahner, David P; Blickendorf, J Matthew; Bockbrader, Marcia; Adkins, Eric; Vira, Amar; Boulger, Creagh; Panchal, Ashish R

    2016-01-01

    There is a need for consistent, repetitive, and reliable terminology to describe the basic manipulations of the ultrasound transducer. Previously, 5 basic transducer motions have been defined and used in education. However, even with this effort, there is still a lack of consistency and clarity in describing transducer manipulation and motion. In this technical innovation, we describe an expanded definition of transducer motions, which include movements to change the transducer's angle of insonation to the target as well as the location on the body to optimize the ultrasound image. This new terminology may allow for consistent teaching and improved communication in the process of image acquisition.

  14. A Neoprene with Optimized Bondability for Sonar Transducer Applications

    DTIC Science & Technology

    1987-06-05

    TR-317R TRANSDUCER The TR-317R is a tonpilz transducer mounted in a large spherical array on the front of U.S. Navy submarines of several classes... TRANSDUCER APPLICATIONS TASK NO. 59-0593-0 [SQ-ns«A-n WORK UNIT ACCESSION NO. )N880-326 12. PERSONAL AUTHOR(S) "^ ^Zl!l ^’ ’^’^°"’P"°" ^"i... Transducer Applications tX: C. M. Thompson Materials Section Transducer Branch Underwater Sound Reference Detachment Naval Research Laboratory P.O

  15. Transthoracic needle aspiration in solitary pulmonary nodule

    PubMed Central

    Yang, Wen; Jiang, Hongli; Khan, Ali Nawaz; Allen, Carolyn; Bertolaccini, Luca

    2017-01-01

    With improved awareness of public health and the recent advances in various imaging technologies, the detection rate of solitary pulmonary nodules (SPN) is continuously increasing. Transthoracic needle aspiration (TTNA) has represented a major approach for the diagnosis and differential diagnosis of pulmonary masses, owing to its simplicity and minimal invasiveness. This paper demonstrates the role of TTNA in SPN. PMID:28331827

  16. A Modification to Maxwell's Needle Apparatus

    ERIC Educational Resources Information Center

    Soorya, Tribhuvan N.

    2015-01-01

    Maxwell's needle apparatus is used to determine the shear modulus (?) of the material of a wire of uniform cylindrical cross section. Conventionally, a single observation is taken for each observable, and the value of ? is calculated in a single shot. A modification to the above apparatus is made by varying one of the observables, namely the mass…

  17. The Single Needle Lockstitch Machine. Module 1.

    ERIC Educational Resources Information Center

    South Carolina State Dept. of Education, Columbia. Office of Vocational Education.

    This module on parts of the machine, one in a series on the single needle lockstitch sewing machine for student self-study, contains eight sections. Each section contains the following parts: an introduction, directions, an objective, learning activities, student information, student self-check, check-out activities, and an instructor's final…

  18. Transthoracic needle biopsy. What size syringe?

    PubMed

    Yankelevitz, D F; Hayt, D; Henschke, C I

    1995-01-01

    Using a vacuum gauge we demonstrated that with less effort, the identical vacuum can be obtained using a 10-cc syringe as opposed to a 50-cc syringe. We recommend using a 20 cc syringe during transthoracic needle aspiration since the syringe is easier to handle and still allows sufficient vacuum to be developed, even if a small amount of air enters the syringe.

  19. Bubble Growth and Detachment from a Needle

    NASA Astrophysics Data System (ADS)

    Shusser, Michael; Rambod, Edmond; Gharib, Morteza

    1999-11-01

    The release of bubbles from an underwater nozzle or orifice occurs in large number of applications, such as perforated plate columns, blood oxygenators and various methods of water treatment. It is also a widely used method in laboratory research on multiphase flow and acoustics for generating small bubbles in a controlled fashion. We studied experimentally the growth and pinch-off of air bubbles released from a submerged needle into a quiescent liquid or a liquid flowing parallel to the needle. Micron-sized bubbles were generated by an air-liquid dispenser. High-speed imaging was performed to study the formation and detachment of bubbles from the tip of the needle. The impact of the needle diameter was investigated and the size and number of produced bubbles were assessed for different flow rates of air and for different velocities of the imposed upward liquid flow. The results were compared with available theoretical models and numerical computations. The existence of a critical gas flow rate and two regimes of bubble growth were verified.

  20. Distribution of elements in needles of Pinus massoniana (Lamb.) was uneven and affected by needle age.

    PubMed

    Kuang, Yuan Wen; Wen, Da Zhi; Zhou, Guoyi; Liu, Shi Zhong

    2007-02-01

    Macronutrients (P, S, K, Na, Mg, Ca), heavy metals (Fe, Zn, Mn, Cu, Pb, Cr, Ni, Cd,) and Al concentrations as well as values of Ca/Al in the tip, middle and base sections, and sheaths of current year and previous year needles of Pinus massoniana from Xiqiao Mountain were analyzed and the distribution patterns of those elements were compared. The results indicated that many elements were unevenly distributed among the different components of needles. Possible deficiency of P, K, Ca, Mn and Al toxicity occurred in needles under air pollution. Heavy metals may threaten the health of Masson pine. Needle sheaths were good places to look for particulate pollutants, in this case including Fe, Cu, Zn, Pb, Cr, Cd and Al.

  1. Distribution of elements in needles of Pinus massoniana (Lamb.) was uneven and affected by needle age.

    PubMed

    Kuang, Yuan Wen; Wen, Da Zhi; Zhou, Guo Yi; Liu, Shi Zhong

    2007-01-01

    Macronutrients (P, S, K, Na, Mg, Ca), heavy metals (Fe, Zn, Mn, Cu, Pb, Cr, Ni, Cd) and Al concentrations as well as values of Ca/Al in the tip, middle, base sections and sheaths of current year and previous year needles of Pinus massoniana from Xiqiao Mountain were analyzed and the distribution patterns of those elements were compared. The results indicated that many elements were unevenly distributed among the different components of needles. Possible deficiency of P, K, Ca, Mn and Al toxicity occurred in needles under air pollution. Heavy metals may threaten the health of Masson pine. Needle sheaths were good places to look for particulate pollutants, in this case including Fe, Cu, Zn, Pb, Cr, Cd and Al.

  2. Silver Doped 0.9PMN-PT-0.1PZT Composite Films for very High Frequency Ultrasonic Transducer Applications.

    PubMed

    Hsu, Hsiu-Sheng; Benjauthrit, Vatcharee; Wei, Qiang; Huang, Yuhong; Zhou, Qifa; Shung, K Kirk

    2013-05-01

    A series of silver doping concentration into the 0.9PMN-PT-0.1PZT (PMN-PT-PZT) films via the composite sol-gel technique were prepared. The crystallographic properties and microstructures of PMN-PT-PZT films with the silver dopant were investigated. Additionally, the effect of silver doping on dielectric and ferroelectric properties was examined. The results show that in general, the dielectric permittivity and remnant polarization increase as the silver doping concentration is increased. The PMN-PT-PZT+ 2.5 mol% Ag film exhibits a dielectric constant of 3,610 at 1 kHz and a remnant polarization of 57.6 µC/cm(2) at room temperature. From this silver doped film, very high frequency ultrasonic needle transducers were fabricated and evaluated. The representative transducer had the center frequency of 225 MHz with a -6 dB bandwidth of 29% (65 MHz) and 62 dB insertion loss. The performance of this transducer is comparable to other composite sol-gel films transducer. The results suggest that this silver-doped PMN-PT-PZT film is a promising candidate as an alternative piezoelectric film for very high frequency transducer applications.

  3. Linear Array Ultrasonic Transducers: Sensitivity and Resolution Study

    SciTech Connect

    Kramb, V.A.

    2005-04-09

    The University of Dayton Research Institute (UDRI) under contract by the US Air Force has designed and integrated a fully automated inspection system for the inspection of turbine engines that incorporates linear phased array ultrasonic transducers. Phased array transducers have been successfully implemented into weld and turbine blade root inspections where the defect types are well known and characterized. Embedded defects in aerospace turbine engine components are less well defined, however. In order to determine the applicability of linear arrays to aerospace inspections the sensitivity of array transducers to embedded defects in engine materials must be characterized. In addition, the implementation of array transducers into legacy inspection procedures must take into account any differences in sensitivity between the array transducer and that of the single element transducer currently used. This paper discusses preliminary results in a study that compares the sensitivity of linear array and conventional single element transducers to synthetic hard alpha defects in a titanium alloy.

  4. Environmental control system transducer development study. [for space shuttles

    NASA Technical Reports Server (NTRS)

    Brudnicki, M. J.

    1974-01-01

    A development test program of transducers for aerospace projects is described. Stability and performance of existing transducers, and improvements compatible with shuttle ECS requirements are investigated. These requirements incorporate design and development features into the transducers, and include the following: (1) improvement of overall transducer ruggedness and reliability; (2) common transducers for all ECS fluids that will be unaffected by long quiescent periods in the space environment, that will require no maintenance or refurbishing for at least 100 launches; and (3) appropriate self-check features that simplify checkout and maintenance. Models of three different transducers, a three-way valve for pressure transducers from closed liquid loops, surface-type platinum-wire resistance temperature sensors, and a nuclenics gaging system are evaluated. Tests and development improvements are described.

  5. New Methods and Transducer Designs for Ultrasonic Diagnostics and Therapy

    NASA Astrophysics Data System (ADS)

    Rybyanets, A. N.; Naumenko, A. A.; Sapozhnikov, O. A.; Khokhlova, V. A.

    Recent advances in the field of physical acoustics, imaging technologies, piezoelectric materials, and ultrasonic transducer design have led to emerging of novel methods and apparatus for ultrasonic diagnostics, therapy and body aesthetics. The paper presents the results on development and experimental study of different high intensity focused ultrasound (HIFU) transducers. Technological peculiarities of the HIFU transducer design as well as theoretical and numerical models of such transducers and the corresponding HIFU fields are discussed. Several HIFU transducers of different design have been fabricated using different advanced piezoelectric materials. Acoustic field measurements for those transducers have been performed using a calibrated fiber optic hydrophone and an ultrasonic measurement system (UMS). The results of ex vivo experiments with different tissues as well as in vivo experiments with blood vessels are presented that prove the efficacy, safety and selectivity of the developed HIFU transducers and methods.

  6. Linear Array Ultrasonic Transducers: Sensitivity and Resolution Study

    NASA Astrophysics Data System (ADS)

    Kramb, V. A.

    2005-04-01

    The University of Dayton Research Institute (UDRI) under contract by the US Air Force has designed and integrated a fully automated inspection system for the inspection of turbine engines that incorporates linear phased array ultrasonic transducers. Phased array transducers have been successfully implemented into weld and turbine blade root inspections where the defect types are well known and characterized. Embedded defects in aerospace turbine engine components are less well defined, however. In order to determine the applicability of linear arrays to aerospace inspections the sensitivity of array transducers to embedded defects in engine materials must be characterized. In addition, the implementation of array transducers into legacy inspection procedures must take into account any differences in sensitivity between the array transducer and that of the single element transducer currently used. This paper discusses preliminary results in a study that compares the sensitivity of linear array and conventional single element transducers to synthetic hard alpha defects in a titanium alloy.

  7. An accuracy statement for a facility used to calibrate static pressure transducers and differential pressure transducers at high base pressure

    NASA Astrophysics Data System (ADS)

    Sindt, C. F.; Labrecque, J. F.

    1982-06-01

    A facility was developed to calibrate pressure transducers that are used in a gas mass flow facility. Both static and differential pressure transducers can be calibrated. An air dead weight tester is the standard for static transducers in the range from 3.8 to 4.5 MPa. An air dead weight tester is also the standard for the differential pressure transducers in the range of 2.5 kPa to 50 MPa; a cistern manometer. This, plus the uncertainties in the high pressure corrections to the cistern manometer and measurement of the mercury temperature, contributes plus or minus 690 ppm to the uncertainty of the differential pressure transducer calibrations.

  8. Performance of Transducers with Segmented Piezoelectric Stacks using Materials with High Electromechanical Coupling Coefficient

    DTIC Science & Technology

    2012-12-03

    transducers , particularly tonpilz transducer elements. Included is discussion of transducer designs using single crystal piezoelectric material with... tonpilz transducer elements. Included is discussion of transducer designs using single crystal piezoelectric material with high coupling coefficient...Conclusions 14 References 16 Appendix 18 v This page intentionally left blank. vi List of Figures Figure 1 The tonpilz transducer element used in this

  9. Dual mode fuel injector with one piece needle valve member

    DOEpatents

    Lawrence, Keith E.; Hinrichsen, Michael H.; Buckman, Colby

    2005-01-18

    A fuel injector includes a homogenous charge nozzle outlet set and a conventional nozzle outlet set controlled respectively by inner and outer needle value members. The homogenous charged nozzle outlet set is defined by an outer needle value member that is moveably positioned in an injector body, which defines the conventional nozzle outlet set. The inner needle valve member is positioned in the outer needle valve member. The outer needle valve member is a piece component that includes at least one external guide surface, an external value surface and an internal valve seat.

  10. The research of knitting needle status monitoring setup

    NASA Astrophysics Data System (ADS)

    Liu, Lu; Liao, Xiao-qing; Zhu, Yong-kang; Yang, Wei; Zhang, Pei; Zhao, Yong-kai; Huang, Hui-jie

    2013-09-01

    In textile production, quality control and testing is the key to ensure the process and improve the efficiency. Defect of the knitting needles is the main factor affecting the quality of the appearance of textiles. Defect detection method based on machine vision and image processing technology is universal. This approach does not effectively identify the defect generated by damaged knitting needles and raise the alarm. We developed a knitting needle status monitoring setup using optical imaging, photoelectric detection and weak signal processing technology to achieve real-time monitoring of weaving needles' position. Depending on the shape of the knitting needle, we designed a kind of Glass Optical Fiber (GOF) light guides with a rectangular port used for transmission of the signal light. To be able to capture the signal of knitting needles accurately, we adopt a optical 4F system which has better imaging quality and simple structure and there is a rectangle image on the focal plane after the system. When a knitting needle passes through position of the rectangle image, the reflected light from needle surface will back to the GOF light guides along the same optical system. According to the intensity of signals, the computer control unit distinguish that the knitting needle is broken or curving. The experimental results show that this system can accurately detect the broken needles and the curving needles on the knitting machine in operating condition.

  11. Needle insertion with duty-cycled rotation into multiple media.

    PubMed

    Lehocky, Craig A; Riviere, Cameron N

    2012-01-01

    Thin, flexible needles can be steered along nonlinear paths to reach deep anatomical structures within the human body. This study builds upon previous work involving steering of bevel-tipped needles by inserting while rotating in a duty-cycled fashion. Here we investigate how needle material and radius, duty cycle, and tissue stiffness affect needle curvature. Needles were inserted into media while rotated at a specified duty cycle and the curvature was measured. A linear relationship between duty cycle and curvature was observed across all needle materials and radii, and tissue stiffnesses. Following these observations, we developed a model that encapsulates needle and tissue parameters in order to predict the duty cycle needed to achieve a desired curvature.

  12. Tip-holed spinal needle: a new design concept.

    PubMed

    Jahangir, S M

    2000-01-01

    Dura-arachnoid puncture for spinal anesthesia is associated with several complications. Postdural puncture headache (PDPH) and needle bending are significant among these. The incidence of PDPH has been reduced significantly with the advent of pencil-point needles. However, these needles also have their limitations, such as obstruction of the delivery port by tissues affecting both cerebrospinal fluid flash back and drug delivery. Increasing the size of the lateral hole has led to mechanical complications, such as tip bending. A new spreading beveled spinal needle tip has been designed to overcome the disadvantages of all the currently used spinal needles. To assess the feasibility, a 26-gauge Quincke spinal needle (B. Braun, Melsungen, Germany) has been modified manually. The new tip-holed design seems to be sound both from theoretical and practical point of view. Searching Medline Plus through their Internet Web site (www.nlm.nih.com) did not reveal the existence of any such spinal needle.

  13. Mixed mode fuel injector with individually moveable needle valve members

    DOEpatents

    Stewart, Chris; Chockley, Scott A.; Ibrahim, Daniel R.; Lawrence, Keith; Tomaseki, Jay; Azam, Junru H.; Tian, Steven Ye; Shafer, Scott F.

    2004-08-03

    A fuel injector includes a homogenous charge nozzle outlet set and a conventional nozzle outlet set controlled respectively, by first and second needle valve members. One of the needle valve members moves to an open position while the other needle valve member remains stationary for a homogeneous charge injection event. The former needle valve member stays stationary while the other needle valve member moves to an open position for a conventional injection event. One of the needle valve members is at least partially positioned in the other needle valve member. Thus, the injector can perform homogeneous charge injection events, conventional injection events, or even a mixed mode having both types of injection events in a single engine cycle.

  14. Torsional dynamics of steerable needles: modeling and fluoroscopic guidance.

    PubMed

    Swensen, John P; Lin, MingDe; Okamura, Allison M; Cowan, Noah J

    2014-11-01

    Needle insertions underlie a diversity of medical interventions. Steerable needles provide a means by which to enhance existing needle-based interventions and facilitate new ones. Tip-steerable needles follow a curved path and can be steered by twisting the needle base during insertion, but this twisting excites torsional dynamics that introduce a discrepancy between the base and tip twist angles. Here, we model the torsional dynamics of a flexible rod-such as a tip-steerable needle-during subsurface insertion and develop a new controller based on the model. The torsional model incorporates time-varying mode shapes to capture the changing boundary conditions inherent during insertion. Numerical simulations and physical experiments using two distinct setups-stereo camera feedback in semitransparent artificial tissue and feedback control with real-time X-ray imaging in optically opaque artificial tissue-demonstrate the need to account for torsional dynamics in control of the needle tip.

  15. MR-compatible biopsy needle with enhanced tip force sensing.

    PubMed

    Elayaperumal, Santhi; Bae, Jung Hwa; Christensen, David; Cutkosky, Mark R; Daniel, Bruce L; Costa, Joannes M; Black, Richard J; Faridian, Fereydoun; Moslehi, Behzad

    2013-04-01

    We describe an instrumented biopsy needle that provides physicians the capability to sense interaction forces directly at the tip of the needle's inner stylet. The sensors consist of optical fiber Bragg gratings (FBGs), and are unaffected by electromagnetic fields; hence the needle is suitable for MR-guided procedures. In comparison to previous instrumented needles that measure bending strains, the new design has additional sensors and a series of micro-machined holes at the tip. The holes increase strain sensitivity, especially to axial forces, without significantly reducing the stiffness or strength. A comparison of the dynamic forces measured with the new needle and those obtained using a force/torque sensor at the needle base shows that the enhanced tip sensitivity is particularly noticeable when there is significant friction along the needle sleeve.

  16. Needle Insertion with Duty-Cycled Rotation into Multiple Media

    PubMed Central

    Lehocky, Craig A.; Riviere, Cameron N.

    2012-01-01

    Thin, flexible needles can be steered along nonlinear paths to reach deep anatomical structures within the human body. This study builds upon previous work involving steering of bevel-tipped needles by inserting while rotating in a duty-cycled fashion. Here we investigate how needle material and radius, duty cycle, and tissue stiffness affect needle curvature. Needles were inserted into media while rotated at a specified duty cycle and the curvature was measured. A linear relationship between duty cycle and curvature was observed across all needle materials and radii, and tissue stiffnesses. Following these observations, we developed a model that encapsulates needle and tissue parameters in order to predict the duty cycle needed to achieve a desired curvature. PMID:23366042

  17. Basic technique in endoscopic ultrasound-guided fine needle aspiration for solid lesions: What needle is the best?

    PubMed Central

    Lachter, Jesse

    2014-01-01

    Basic technique for endoscopic ultrasound (EUS) of solid lesions has developed during 30 years of EUS, as endoscopes and accessory equipment, particularly needles, have been developed. Systematic high-quality examinations require understanding and planning. Needles used for EUS-guided fine needle aspiration (FNA) have gone through many improvements; some 18 characteristics of any needle are presented and these come under consideration whenever choosing the best needle for each procedure. The bright future of EUS and FNA for solid lesions currently still leaves much room for continued developments. PMID:24949410

  18. An Exploration of the Needling Depth in Acupuncture: The Safe Needling Depth and the Needling Depth of Clinical Efficacy

    PubMed Central

    Lin, Jaung-Geng; Chou, Pei-Chi; Chu, Heng-Yi

    2013-01-01

    Objective. To explore the existing scientific information regarding safe needling depth of acupuncture points and the needling depth of clinical efficacy. Methods. We searched the PubMed, EMBASE, Cochrane, Allied and Complementary Medicine (AMED), The National Center for Complementary and Alternative Medicine (NCCAM), and China National Knowledge Infrastructure (CNKI) databases to identify relevant monographs and related references from 1991 to 2013. Chinese journals and theses/dissertations were hand searched. Results. 47 studies were recruited and divided into 6 groups by measuring tools, that is, MRI, in vivo evaluation, CT, ultrasound, dissected specimen of cadavers, and another group with clinical efficacy. Each research was analyzed for study design, definition of safe depth, and factors that would affect the measured depths. Depths of clinical efficacy were discussed from the perspective of de-qi and other clinical observations. Conclusions. Great inconsistency in depth of each point measured from different subject groups and tools exists. The definition of safe depth should be established through standardization. There is also lack of researches to compare the clinical efficacy. A well-designed clinical trial selecting proper measuring tools to decide the actual and advisable needling depth for each point, to avoid adverse effects or complications and promote optimal clinical efficacy, is a top priority. PMID:23935678

  19. [Needling technique of Professor Li Yan-Fang].

    PubMed

    Li, Li-Jun

    2014-01-01

    Experiences of needling techniques of Professor LI Ya- fang is introduced in this article. Gentle and superficial insertion is adopted by Professor LI in clinic. Emphases are put on the qi regulation function, needling sensation to the affected region and insertion with both hands, especially the function of the left hand as pressing hand. The gentle and superficial insertion should be done as the follows: hold the needle with the right hand, press gently along the running course of meridians with the left hand to promote qi circulation, hard pressing should be applied at acupoints to disperse the local qi and blood, insert the needle gently and quickly into the subcutaneous region with the right hand, and stop the insertion when patient has the needling sensation. While the fast needling is characterized with shallow insertion and swift manipulation: the left hand of the manipulator should press first along the running course of the meridian, and fix the local skin, hold the needle with the right hand and insert the needle quickly into the acupoint. Withdrawal of the needle should be done immediately after the reinforcing and reducing manipulations. Professor LI is accomplished in qi regulation. It is held by him that regulating qi circulation is essence of acupuncture, letting the patient get the needling sensation is the most important task of needling. Lifting, thrusting and rotation manipulations should be applied to do reinforcing or reducing. The tissue around the tip of the needle should not be too contracted or too relaxed, and the resistance should not be too strong or too weak. The feeling of the insertion hand of the practitioner should not be too smooth or too hesitant. Needle should be inserted into the skin quickly at the moment of hard pressing by the left hand. And then, slow rotation and gentle lifting and thrusting can be applied to promote the needling sensation like electric current pass through and to reach the affected region along the

  20. Safety Issues for HIFU Transducer Design

    NASA Astrophysics Data System (ADS)

    Fleury, Gérard; Berriet, Rémi; Chapelon, Jean Yves; ter Haar, Gail; Lafon, Cyril; Le Baron, Olivier; Chupin, Laurent; Pichonnat, Fabrice; Lenormand, Jérôme

    2005-03-01

    In contrast with most ultrasound modalities for medical applications, (especially ultrasound imaging), High Intensity Focused Ultrasound (HIFU) involves technologies and procedures which may present risk to the patient. These risks, resulting from the high power levels required for effective therapy, should be taken into account at the earliest stages in the design of a system dedicated to HIFU treatment. An understanding of these risks must thus be shared amongst the many players in the field of therapy using high power ultrasound. Moreover, since the number of applications of HIFU has increased appreciably over recent years and the technology is ready to move from the research to the industrial level, it is worth now considering solutions that should be put in place to guarantee the safety of the patient during HIFU treatment. This paper reports thoughts on this, identifies some risks to the patient that must be taken into consideration in the design of HIFU transducers, and proposes some solutions that could prevent the deleterious consequences of transducer misuse or failure. For the main risks identified, such as exceeding the desired acoustic power or poor control of tissue targeting, a description of transducer performance that could potentially result in problems is systematically sought. This allows proposals for precautions to be taken during operation to be made. Parameters which should be monitored to ensure safe use are also suggested. This type of approach, which should be undertaken for the different components of a therapeutic system, highlights the challenges that must be faced in the immediate future for the development and safe exploitation of HIFU systems. The necessity for standard definitions of the parameters to be checked or monitored during HIFU treatments is crucial in this approach, as is the availability of reliable dedicated measurement devices. Co-ordinated action on these topics in the HIFU community would contribute to the

  1. Electromagnetic acoustic transducers (EMATs) for erosion monitoring

    SciTech Connect

    Reimann, K.J.

    1984-05-01

    Early detection, measurement, and monitoring of erosive wear rates can alleviate problems of unpredictable shutdowns, costly downtimes, and improper process operation. The first generation of a nondestructive, noninvasive acoustic-based system was tested on pressure boundaries of fossil energy conversion plants, yielding the desired information. Multiple transducers and wave guides are needed for such a system in order to determine wear profiles in large components. The same information could, however, be obtained with a single, scanning electromagnetic transducer (EMAT). Advantages of such EMAT-based systems motivated this investigation in order to establish criteria and requirements needed for erosion monitoring at elevated (operating) temperatures. The effort concentrated on three areas: (a) development of EMAT design parameters, (b) material-EMAT interaction, and (c) signal processing. Prototype horizontal shearwave EMATs, based on design parameters selected from computer calculations of the static field, were evaluated, and their performance was compared to the performance of piezoelectric transducers. Input power requirements for a larger than 10-dB signal-to-noise (S/N) ratio were established for various structural and hardfacing materials. Effects of surface roughness and temperature were determined for different test conditions. The results indicate that accurate wall thickness measurement can be performed at elevated temperature on rough surfaces as encountered, for instance, in a cyclone. Modern data processing such as signal averaging on correlation improves the S/N ratio from 12 dB to 26 dB and enables wall thickness measurements with an accuracy of +-0.25% of total wall thickness. Additional efforts are needed to determine requirements of EMATs in scanning mode and pulsed static field operation.

  2. Piezoelectric and Electrostrictive Materials for Transducer Applications.

    DTIC Science & Technology

    1984-05-01

    8217IIALMYH iEjn 4R2i 33 E I2/3N 1.0 I. I 1.85 PIZOLKCTRIC AND ELECTIOSTRICrIVE NATRIALS FOR TRANSDUCER APPLICATIONS Annual Report to OFFICE OF NAVAL...So UNCL.ASSIFIED SECURITY CLASSI FICATION OF THIS PAGE 1Wan Do#* ffnt.,.d) REPORT DOCUMENTATION...PAGE BEFRECMLEIN ORM 1REPORT NUMBER 2. oV ACCESSION NO 1. RECIPIENT*$ CATAL.OG NUMBER 4. TITY6 EHI Subtite.) S. TYPE OF REPORT a PERIOD COVERED

  3. Piezoelectric and electrostrictive materials for transducer applications

    NASA Astrophysics Data System (ADS)

    Cross, L. E.; Newnham, R. E.; Barsch, G. R.; Biggers, J. V.

    1984-05-01

    A wide range of materials and devices were covered, including composite materials for transducer applications, electrostriction, and conventional piezoelectrics. In piezoelectric composites, progress was made in 3:1 and 3:2 perforated PZT polymer composites, and in transverse reinforced composites. Finite element calculations of stress distributions in 1:3 PZT polymer composites were carried out. Fresnoite glass ceramics have exhibited extreme stability to hydrostatic pressure, and high sensitivity. A new water quenching technique was used to develop PbTiO3, and a detailed analysis of resonant modes of 1:3 PZT epoxy composites was carried out.

  4. A high-temperature wideband pressure transducer

    NASA Technical Reports Server (NTRS)

    Zuckerwar, A. J.

    1975-01-01

    Progress in the development of a pressure transducer for measurement of the pressure fluctuations in the high temperature environment of a jet exhaust is reported. A condenser microphone carrier system was adapted to meet the specifications. A theoretical analysis is presented which describes the operation of the condenser microphone in terms of geometry, materials, and other physical properties. The analysis was used as the basis for design of a prototype high temperature microphone. The feasibility of connecting the microphone to a converter over a high temperature cable operating as a half-wavelength transmission line was also examined.

  5. Detecting stages of needle penetration into tissues through force estimation at needle tip using fiber Bragg grating sensors

    NASA Astrophysics Data System (ADS)

    Kumar, Saurabh; Shrikanth, Venkoba; Amrutur, Bharadwaj; Asokan, Sundarrajan; Bobji, Musuvathi S.

    2016-12-01

    Several medical procedures involve the use of needles. The advent of robotic and robot assisted procedures requires dynamic estimation of the needle tip location during insertion for use in both assistive systems as well as for automatic control. Most prior studies have focused on the maneuvering of solid flexible needles using external force measurements at the base of the needle holder. However, hollow needles are used in several procedures and measurements of forces in proximity of such needles can eliminate the need for estimating frictional forces that have high variations. These measurements are also significant for endoscopic procedures in which measurement of forces at the needle holder base is difficult. Fiber Bragg grating sensors, due to their small size, inert nature, and multiplexing capability, provide a good option for this purpose. Force measurements have been undertaken during needle insertion into tissue mimicking phantoms made of polydimethylsiloxane as well as chicken tissue using an 18-G needle instrumented with FBG sensors. The results obtained show that it is possible to estimate the different stages of needle penetration including partial rupture, which is significant for procedures in which precise estimation of needle tip position inside the organ or tissue is required.

  6. Photoacoustic-guided focused ultrasound for accurate visualization of brachytherapy seeds with the photoacoustic needle

    NASA Astrophysics Data System (ADS)

    Singh, Mithun Kuniyil Ajith; Parameshwarappa, Vinay; Hendriksen, Ellen; Steenbergen, Wiendelt; Manohar, Srirang

    2016-12-01

    An important problem in minimally invasive photoacoustic (PA) imaging of brachytherapy seeds is reflection artifacts caused by the high signal from the optical fiber/needle tip reflecting off the seed. The presence of these artifacts confounds interpretation of images. In this letter, we demonstrate a recently developed concept called photoacoustic-guided focused ultrasound (PAFUSion) for the first time in the context of interstitial illumination PA imaging to identify and remove reflection artifacts. In this method, ultrasound (US) from the transducer is focused on the region of the optical fiber/needle tip identified in a first step using PA imaging. The image developed from the US diverging from the focus zone at the tip region visualizes only the reflections from seeds and other acoustic inhomogeneities, allowing identification of the reflection artifacts of the first step. These artifacts can then be removed from the PA image. Using PAFUSion, we demonstrate reduction of reflection artifacts and thereby improved interstitial PA visualization of brachytherapy seeds in phantom and ex vivo measurements on porcine tissue.

  7. Towards synergistic control of hands-on needle insertion with automated needle steering for MRI-guided prostate interventions.

    PubMed

    Wartenberg, Marek; Patel, Niravkumar; Gang Li; Fischer, Gregory S

    2016-08-01

    A significant hurdle of accurate needle tip placement in percutaneous needle-based prostate interventions is unmodeled needle deflection and tissue deformation during insertion. This paper introduces a robotic platform for developing synergistic, cooperatively controlled needle insertion algorithms decoupled from closed-loop image-guided needle steering. Shared control of the surgical workspace through human-robot synergy creates a balance between the accuracy of robotic autonomy while still providing ultimate control of the procedure to the physician. Validation tests were performed using camera-based image-guided feedback control of needle steering with cooperative hands-on needle insertion. Locations were targeted inside a transparent gelatin phantom with an average total error of 2.68 ± 0.34mm and in-plane error of 2.59 ± 0.30mm.

  8. Maxillofacial Changes in Melnick-Needles Syndrome

    PubMed Central

    Albuquerque do Nascimento, Leilane Larissa; Salgueiro, Monica da Consolação Canuto; Quintela, Mariana; Mota, Ana Carolina Costa

    2016-01-01

    Background. Melnick-Needles Syndrome is rare congenital hereditary skeletal dysplasia caused by mutations in the FLNA gene, which codifies the protein filamin A. This condition leads to serious skeletal abnormalities, including the stomatognathic region. Case Presentation. This paper describes the case of a 13-year-old girl diagnosed with Melnick-Needles Syndrome presenting with different forms of skeletal dysplasia, such as cranial hyperostosis, short upper limbs, bowed long bones, metaphyseal thickening, genu valgum (knock-knee), shortened distal phalanges, narrow pelvis and shoulders, rib tapering and irregularities, elongation of the vertebrae, kyphoscoliosis, micrognathia, hypoplastic coronoid processes of the mandible, left stylohyoid ligament suggesting ossification, and dental development anomalies. Conclusion. Knowledge of this rare syndrome on the part of dentists is important due to the fact that this condition involves severe abnormalities of the stomatognathic system that cause an impact on the development of the entire face as well as functional and esthetic impairments. PMID:27478655

  9. Intraoperative Optical Coherence Tomography Guided Bleb Needling.

    PubMed

    Dada, Tanuj; Angmo, Dewang; Midha, Neha; Sidhu, Talvir

    2016-01-01

    Two patients with history of trabeculectomy presented with uncontrolled intraocular pressure (IOP) postoperatively. The first patient had a flat and vasularized bleb 10 weeks after the surgery, and the second subject developed encapsulated bleb 3 months postoperatively. Both patients were taken to the operating room and intraoperative optical coherence tomography (OCT) guided bleb needling was performed to restore aqueous egress into the subconjunctival space. Postoperatively, IOP of the operated eyes ranged 14-18 mmHg at week 6 and month 3. None of the eyes had any intraoperative or postoperative complications. This novel application of the intraoperative OCT for bleb needling facilitates precision surgery under direct visualization and reduces the risk of complications.

  10. Intraoperative Optical Coherence Tomography Guided Bleb Needling

    PubMed Central

    Dada, Tanuj; Angmo, Dewang; Midha, Neha; Sidhu, Talvir

    2016-01-01

    Two patients with history of trabeculectomy presented with uncontrolled intraocular pressure (IOP) postoperatively. The first patient had a flat and vasularized bleb 10 weeks after the surgery, and the second subject developed encapsulated bleb 3 months postoperatively. Both patients were taken to the operating room and intraoperative optical coherence tomography (OCT) guided bleb needling was performed to restore aqueous egress into the subconjunctival space. Postoperatively, IOP of the operated eyes ranged 14-18 mmHg at week 6 and month 3. None of the eyes had any intraoperative or postoperative complications. This novel application of the intraoperative OCT for bleb needling facilitates precision surgery under direct visualization and reduces the risk of complications. PMID:27994819

  11. Melnick- needles osteodysplasty presenting with quadriparesis.

    PubMed

    Bandyopadhyay, S K; Ghosal, J; Chakrabarti, Nandini; Dutta, Anita

    2006-03-01

    Melnick-Needles syndrome or osteodysplasty, a monogenic heritable bone dysplasia, is characterized by a typical facies and characteristic radiological findings. Less than 70 well-documented cases have been reported in literature; most of them were sporadic. We report the first case from Eastern India in an adolescent male, who had cranio-vertebral junction anomalies and presented with spastic quadriparesis at the age of 13 years.

  12. Electrical needle therapy of uremic pruritus.

    PubMed

    Duo, L J

    1987-01-01

    Six patients with intractable uremic pruritus were treated with a modified acupuncture technique, the electrical needle stimulation (ENS). Results were followed with a pruritic score scale based on severity, frequency and distribution of itching, together with sleeping hours and waking up at night. The results were encouraging: pruritus was drastically improved during or after ENS in several patients. A control treatment with superficial electrical stimulation was ineffective.

  13. Yield of new versus reused endobronchial ultrasound-guided transbronchial needle aspiration needles: A retrospective analysis of 500 patients

    PubMed Central

    Dhooria, Sahajal; Sehgal, Inderpaul Singh; Gupta, Nalini; Ram, Babu; Aggarwal, Ashutosh Nath; Behera, Digambar; Agarwal, Ritesh

    2016-01-01

    Background: Endobronchial ultrasound (EBUS)-guided transbronchial needle aspiration (TBNA) requires a dedicated needle for aspiration of mediastinal lesions. There is no data on reuse of these needles. Methods: This is a retrospective study of patients who underwent EBUS-TBNA with either new or reused EBUS-TBNA needles. The needles were reused after thorough cleaning with filtered water and organic cleaning solution, disinfection with 2.4% glutaraldehyde solution followed by ethylene oxide sterilization. The yield of EBUS-TBNA was compared between the two groups. Results: A total of 500 EBUS-TBNA procedures (351 new, 149 reused needles) were performed. The baseline characteristics were different in the two groups with suspected granulomatous disorders (sarcoidosis or tuberculosis) being significantly more common in the new compared to the reused needle group. Similarly, the median, interquartile range number of lymph node stations sampled, and the total number of passes were significantly higher in the new versus the reused needle group. The diagnostic yield was significantly higher with new needle as compared to reused needle (65.2% vs. 53.7%, P = 0.02). On multivariate logistic regression analysis, clinical suspicion of granulomatous disorders (odds ratio 1.86 [95% confidence interval, 1.20-2.87], P = 0.005) was the only predictor of diagnostic yield, after adjusting for the type of needle (new or reused), total number of passes and the number of lymph node stations sampled. No case of mediastinitis was encountered in either group. Conclusions: The yield of EBUS-TBNA might be similar with single reuse of needles as compared to new needles. However, reuse of needle should be performed only when absolutely necessary. PMID:27578927

  14. Randomized Trial of Conventional Transseptal Needle Versus Radiofrequency Energy Needle Puncture for Left Atrial Access (the TRAVERSE‐LA Study)

    PubMed Central

    Hsu, Jonathan C.; Badhwar, Nitish; Gerstenfeld, Edward P.; Lee, Randall J.; Mandyam, Mala C.; Dewland, Thomas A.; Imburgia, Kourtney E.; Hoffmayer, Kurt S.; Vedantham, Vasanth; Lee, Byron K.; Tseng, Zian H.; Scheinman, Melvin M.; Olgin, Jeffrey E.; Marcus, Gregory M.

    2013-01-01

    Background Transseptal puncture is a critical step in achieving left atrial (LA) access for a variety of cardiac procedures. Although the mechanical Brockenbrough needle has historically been used for this procedure, a needle employing radiofrequency (RF) energy has more recently been approved for clinical use. We sought to investigate the comparative effectiveness of an RF versus conventional needle for transseptal LA access. Methods and Results In this prospective, single‐blinded, controlled trial, 72 patients were randomized in a 1:1 fashion to an RF versus conventional (BRK‐1) transseptal needle. In an intention‐to‐treat analysis, the primary outcome was time required for transseptal LA access. Secondary outcomes included failure of the assigned needle, visible plastic dilator shavings from needle introduction, and any procedural complication. The median transseptal puncture time was 68% shorter using the RF needle compared with the conventional needle (2.3 minutes [interquartile range {IQR}, 1.7 to 3.8 minutes] versus 7.3 minutes [IQR, 2.7 to 14.1 minutes], P=0.005). Failure to achieve transseptal LA access with the assigned needle was less common using the RF versus conventional needle (0/36 [0%] versus 10/36 [27.8%], P<0.001). Plastic shavings were grossly visible after needle advancement through the dilator and sheath in 0 (0%) RF needle cases and 12 (33.3%) conventional needle cases (P<0.001). There were no differences in procedural complications (1/36 [2.8%] versus 1/36 [2.8%]). Conclusions Use of an RF needle resulted in shorter time to transseptal LA access, less failure in achieving transseptal LA access, and fewer visible plastic shavings. Clinical Trial Registration URL: http://www.clinicaltrials.gov. Unique identifier: NCT01209260. PMID:24045120

  15. Floating Ultrasonic Transducer Inspection System and Method for Nondestructive Evaluation

    NASA Technical Reports Server (NTRS)

    Zalameda, Joseph N. (Inventor); Johnston, Patrick H. (Inventor)

    2016-01-01

    A method for inspecting a structural sample using ultrasonic energy includes positioning an ultrasonic transducer adjacent to a surface of the sample, and then transmitting ultrasonic energy into the sample. Force pulses are applied to the transducer concurrently with transmission of the ultrasonic energy. A host machine processes ultrasonic return pulses from an ultrasonic pulser/receiver to quantify attenuation of the ultrasonic energy within the sample. The host machine detects a defect in the sample using the quantified level of attenuation. The method may include positioning a dry couplant between an ultrasonic transducer and the surface. A system includes an actuator, an ultrasonic transducer, a dry couplant between the transducer the sample, a scanning device that moves the actuator and transducer, and a measurement system having a pulsed actuator power supply, an ultrasonic pulser/receiver, and a host machine that executes the above method.

  16. Using FOCUS to determine the radiation impedance for square transducers

    NASA Astrophysics Data System (ADS)

    Jennings, Matthew R.; McGough, Robert J.

    2012-10-01

    The power radiated by an ultrasound transducer is calculated with the radiation resistance, which is the real part of the radiation impedance. For circular transducers, an analytical solution for the radiation impedance is known, but an analytical expression for the radiation impedance is not available for rectangular or square transducers. To determine the radiation resistance in FOCUS, the pressure on the surface of a square transducer is computed with the fast nearfield method, and then the force on the transducer face is computed by integrating the pressure. Results using this approach are numerically evaluated for a range of ka values from 0.1 to 16. The pressure on the transducer face is also computed with the Rayleigh-Sommerfeld integral, and the results are compared. The numerical value of the radiation resistance computed with FOCUS and with the Rayleigh-Sommerfeld integral converge to the same value, although FOCUS calculates the same result in about one-quarter of the time.

  17. Protein family classification using sparse markov transducers.

    PubMed

    Eskin, Eleazar; Noble, William Stafford; Singer, Yoram

    2003-01-01

    We present a method for classifying proteins into families based on short subsequences of amino acids using a new probabilistic model called sparse Markov transducers (SMT). We classify a protein by estimating probability distributions over subsequences of amino acids from the protein. Sparse Markov transducers, similar to probabilistic suffix trees, estimate a probability distribution conditioned on an input sequence. SMTs generalize probabilistic suffix trees by allowing for wild-cards in the conditioning sequences. Since substitutions of amino acids are common in protein families, incorporating wild-cards into the model significantly improves classification performance. We present two models for building protein family classifiers using SMTs. As protein databases become larger, data driven learning algorithms for probabilistic models such as SMTs will require vast amounts of memory. We therefore describe and use efficient data structures to improve the memory usage of SMTs. We evaluate SMTs by building protein family classifiers using the Pfam and SCOP databases and compare our results to previously published results and state-of-the-art protein homology detection methods. SMTs outperform previous probabilistic suffix tree methods and under certain conditions perform comparably to state-of-the-art protein homology methods.

  18. Orbital Angular Momentum-Entanglement Frequency Transducer

    NASA Astrophysics Data System (ADS)

    Zhou, Zhi-Yuan; Liu, Shi-Long; Li, Yan; Ding, Dong-Sheng; Zhang, Wei; Shi, Shuai; Dong, Ming-Xin; Shi, Bao-Sen; Guo, Guang-Can

    2016-09-01

    Entanglement is a vital resource for realizing many tasks such as teleportation, secure key distribution, metrology, and quantum computations. To effectively build entanglement between different quantum systems and share information between them, a frequency transducer to convert between quantum states of different wavelengths while retaining its quantum features is indispensable. Information encoded in the photon's orbital angular momentum (OAM) degrees of freedom is preferred in harnessing the information-carrying capacity of a single photon because of its unlimited dimensions. A quantum transducer, which operates at wavelengths from 1558.3 to 525 nm for OAM qubits, OAM-polarization hybrid-entangled states, and OAM-entangled states, is reported for the first time. Nonclassical properties and entanglements are demonstrated following the conversion process by performing quantum tomography, interference, and Bell inequality measurements. Our results demonstrate the capability to create an entanglement link between different quantum systems operating in a photon's OAM degrees of freedom, which will be of great importance in building a high-capacity OAM quantum network.

  19. Acoustic lens for capacitive micromachined ultrasonic transducers

    NASA Astrophysics Data System (ADS)

    Chang, Chienliu; Firouzi, Kamyar; Park, Kwan Kyu; Sarioglu, Ali Fatih; Nikoozadeh, Amin; Yoon, Hyo-Seon; Vaithilingam, Srikant; Carver, Thomas; Khuri-Yakub, Butrus T.

    2014-08-01

    Capacitive micromachined ultrasonic transducers (CMUTs) have great potential to compete with traditional piezoelectric transducers in therapeutic ultrasound applications. In this paper we have designed, fabricated and developed an acoustic lens formed on the CMUT to mechanically focus ultrasound. The acoustic lens was designed based on the paraxial theory and made of silicone rubber for acoustic impedance matching and encapsulation. The CMUT was fabricated based on the local oxidation of silicon (LOCOS) and fusion-bonding. The fabricated CMUT was verified to behave like an electromechanical resonator in air and exhibited wideband response with a center frequency of 2.2 MHz in immersion. The fabrication for the acoustic lens contained two consecutive mold castings and directly formed on the surface of the CMUT. Applied with ac burst input voltages at the center frequency, the CMUT with the acoustic lens generated an output pressure of 1.89 MPa (peak-to-peak) at the focal point with an effective focal gain of 3.43 in immersion. Compared to the same CMUT without a lens, the CMUT with the acoustic lens demonstrated the ability to successfully focus ultrasound and provided a viable solution to the miniaturization of the multi-modality forward-looking endoscopes without electrical focusing.

  20. Optical piezoelectric transducer for nano-ultrasonics.

    PubMed

    Lin, Kung-Hsuan; Chern, Gia-Wei; Yu, Cheng-Ta; Liu, Tzu-Ming; Pan, Chang-Chi; Chen, Guan-Ting; Chyi, Jen-Inn; Huang, Sheng-Wen; Li, Pai-Chi; Sun, Chi-Kuang

    2005-08-01

    Piezoelectric semiconductor strained layers can be treated as piezoelectric transducers to generate nanometer-wavelength and THz-frequency acoustic waves. The mechanism of nano-acoustic wave (NAW) generation in strained piezoelectric layers, induced by femtosecond optical pulses, can be modeled by a macroscopic elastic continuum theory. The optical absorption change of the strained layers modulated by NAW through quantum-confined Franz-Keldysh (QCFK) effects allows optical detection of the propagating NAW. Based on these piezoelectric-based optical principles, we have designed an optical piezoelectric transducer (OPT) to generate NAW. The optically generated NAW is then applied to one-dimensional (1-D) ultrasonic scan for thickness measurement, which is the first step toward multidimensional nano-ultrasonic imaging. By launching a NAW pulse and resolving the returned acoustic echo signal with femtosecond optical pulses, the thickness of the studied layer can be measured with <1 nm resolution. This nano-structured OPT technique will provide the key toward the realization of nano-ultrasonics, which is analogous to the typical ultrasonic techniques but in a nanometer scale.

  1. Current transducers used in power line measurements

    NASA Astrophysics Data System (ADS)

    Milcarz, Sz.; Gołebiowski, J.

    2014-08-01

    There are many solutions used for current measurements in power lines. The study shows a transducer consisting of a ferromagnetic core, a beam placed in an air-gap and a sensor for optical readout. The beam is made of silicon with a thin 50%Ni50%Fe film. The material of the core is permalloy. A distribution of magnetic field depends on current supplying the power line. The beam is deflected due to magnetic field in the air-gap. A deflection of the beam is measured by the optical fibre sensor. Its advantage is simple design, high precision of processing, non-electric transmission, low costs and ability of a non-contact measurement. Comsol Multiphysics 4.4 and Magnetic Fields Module (mef) were used for modeling. An influence of magnetic circuit's materials and dimensions of the ferromagnetic core and the air-gap were tested in order to determine the most sufficient distribution of magnetic field in the air-gap. The study shows results of the modeling of the transducer compared to practical results for a similar construction scaled down to lower current values.

  2. [Design and application of silver needle-knife].

    PubMed

    Sun, Guodong; Shi, Bin; Zhang, Benwu; Xu, Haidong

    2015-04-01

    A silver needle-knife which has the dual function of silver needle and needle-knife is designed. The main components of this silver needle-knife are approximately 50% silver and approximately 50% nichrome. The silver needle-knife is composed of five parts, including needle-knife tail, spiral handle; steering handle, needle-knife body and needle-knife edge. It converges the advantages of needle-knife and silver needle, which can cut loose of diseased tissue and peel adhesion of lesions, but also be heated with moxa cone and thermal therapeutic instrument, and connect with electroacupuncture apparatus. It has the function of warming channel and removing coldness, dispelling wind and eliminating dampness, resolving spasm and relieving pain, dredging the channel and so on. Due to the spiral handle and the steering handle, the operation is easier, which reduces the blindness of cutting and increase the safety. It is mainly used for soft tissue injury, rheumatism and rheumatoid arthritis, as well as degenerative diseases of spine and joint, and it has obvious efficacy on some internal medical diseases.

  3. Manually controlled steerable needle for MRI-guided percutaneous interventions.

    PubMed

    Henken, Kirsten R; Seevinck, Peter R; Dankelman, Jenny; van den Dobbelsteen, John J

    2017-02-01

    This study aims to develop and evaluate a manually controlled steerable needle that is compatible with and visible on MRI to facilitate full intra-procedural control and accurate navigation in percutaneous interventions. The steerable needle has a working channel that provides a lumen to a cutting stylet or a therapeutic instrument. A steering mechanism based on cable-operated compliant elements is integrated in the working channel. The needle can be steered by adjusting the orientation of the needle tip through manipulation of the handle. The steering mechanism is evaluated by recording needle deflection at constant steering angles. A steering angle of 20.3° results in a deflection of 9.1-13.3 mm in gelatin and 4.6-18.9 mm in porcine liver tissue at an insertion depth of 60 mm. Additionally, the possibility to control the needle path under MRI guidance is evaluated in a gelatin phantom. The needle can be steered to targets at different locations while starting from the same initial position and orientation under MRI guidance with generally available sequences. The steerable needle offers flexibility to the physician in control and choice of the needle path when navigating the needle toward the target position, which allows for optimization of individual treatment and may increase target accuracy.

  4. Electrotactile display using microfabricated micro-needle array

    NASA Astrophysics Data System (ADS)

    Kitamura, N.; Chim, J.; Miki, N.

    2015-02-01

    This paper describes an electrotactile display with micro-needle electrodes. The electrotactile display can produce tactile sensations by stimulating tactile receptors using an electric current. Micro-needle electrodes can drastically decrease the threshold voltage required to stimulate tactile receptors by penetrating the stratum corneum, which has a higher impedance than the dermis. In addition, the optimized length of the needle allows us to stimulate tactile receptors painlessly. In the present study, we developed a process for fabricating a micro-needle array in which the length and tip radius can be controlled using electrochemical etching. A micro-needle array was successfully fabricated to form an electrotactile display. In addition, we experimentally determined the suitable shape of the micro-needle electrodes for electrotactile display applications. When the tip radius of the needle is too small, the impedance between the finger and micro-needles becomes large due to the small contact area. On the other hand, when the tip radius is too large, the needle cannot penetrate the skin surface and the impedance is not sufficiently small. The experiments verified the superiority of needle electrode devices to flat electrode devices with respect to the threshold voltage at each frequency.

  5. Low-cost ultrasonic lamb-wave transducer

    NASA Technical Reports Server (NTRS)

    Kammerer, C. C.

    1978-01-01

    Transducer propagates Lamb wave through thin aluminum sheet material. Model includes two elements that measure effects of damping and loading which, in turn, are indirectly equated to bond integrity. Transducer has been used to evaluate bond integrity of aluminum facing adhesively bonded to aluminum facing. Because of versatility, it is now possible to inspect many objects of different configurations that could not be reached with earlier transducers.

  6. Electret Acoustic Transducer Array For Computerized Ultrasound Risk Evaluation System

    DOEpatents

    Moore, Thomas L.; Fisher, Karl A.

    2005-08-09

    An electret-based acoustic transducer array is provided and may be used in a system for examining tissue. The acoustic transducer array is formed with a substrate that has a multiple distinct cells formed therein. Within each of the distinct cells is positioned an acoustic transducing element formed of an electret material. A conductive membrane is formed over the distinct cells and may be flexible.

  7. Highly reproducible Bragg grating acousto-ultrasonic contact transducers

    NASA Astrophysics Data System (ADS)

    Saxena, Indu Fiesler; Guzman, Narciso; Lieberman, Robert A.

    2014-09-01

    Fiber optic acousto-ultrasonic transducers offer numerous applications as embedded sensors for impact and damage detection in industrial and aerospace applications as well as non-destructive evaluation. Superficial contact transducers with a sheet of fiber optic Bragg gratings has been demonstrated for guided wave ultrasound based measurements. It is reported here that this method of measurement provides highly reproducible guided ultrasound data of the test composite component, despite the optical fiber transducers not being permanently embedded in it.

  8. An Algorithm for Selecting Transducer Element Array Positions

    DTIC Science & Technology

    1988-06-01

    response. A lumped-parameter equivalent circuit of a tonpilz transducer is used to predict element amplitude and phase tolerances for different radiation...lumped-parameter equivalent circuit of a tonpilz transducer is used to predict element amplitude and phase tolerances for different radiation loadings...FIGURES p Figure Page : 2.1 A Tonpilz Type Transducer . . .............. . 6 % 2.2 The Equivalent Circuit .......... .................... 7 2.3 The

  9. Turbulent flow evaluation of the venous needle during hemodialysis.

    PubMed

    Unnikrishnan, Sunil; Huynh, Thanh N; Brott, B C; Ito, Y; Cheng, C H; Shih, A M; Allon, M; Anayiotos, Andreas S

    2005-12-01

    Arteriovenous (AV) grafts and fistulas used for hemodialysis frequently develop intimal hyperplasia (IH) at the venous anastomosis of the graft, leading to flow-limiting stenosis, and ultimately to graft failure due to thrombosis. Although the high AV access blood flow has been implicated in the pathogenesis of graft stenosis, the potential role of needle turbulence during hemodialysis is relatively unexplored. High turbulent stresses from the needle jet that reach the venous anastomosis may contribute to endothelial denudation and vessel wall injury. This may trigger the molecular and cellular cascade involving platelet activation and IH, leading to eventual graft failure. In an in-vitro graft/needle model dye injection flow visualization was used for qualitative study of flow patterns, whereas laser Doppler velocimetry was used to compare the levels of turbulence at the venous anastomosis in the presence and absence of a venous needle jet. Considerably higher turbulence was observed downstream of the venous needle, in comparison to graft flow alone without the needle. While turbulent RMS remained around 0.1 m/s for the graft flow alone, turbulent RMS fluctuations downstream of the needle soared to 0.4-0.7 m/s at 2 cm from the tip of the needle and maintained values higher than 0.1 m/s up to 7-8 cm downstream. Turbulent intensities were 5-6 times greater in the presence of the needle, in comparison with graft flow alone. Since hemodialysis patients are exposed to needle turbulence for four hours three times a week, the role of post-venous needle turbulence may be important in the pathogenesis of AV graft complications. A better understanding of the role of needle turbulence in the mechanisms of AV graft failure may lead to improved design of AV grafts and venous needles associated with reduced turbulence, and to pharmacological interventions that attenuate IH and graft failure resulting from turbulence.

  10. A cost-effective, non-invasive system for pressure monitoring during epidural needle insertion: Design, development and bench tests.

    PubMed

    Tesei, M; Saccomandi, P; Massaroni, C; Quarta, R; Carassiti, M; Schena, E; Setola, R

    2016-08-01

    Epidural blockade procedures have gained large acceptance during last decades. However, the insertion of the needle during epidural blockade procedures is challenging, and there is an increasing alarming risk in accidental dural puncture. One of the most popular approaches to minimize the mentioned risk is to detect the epidural space on the base of the loss of resistance (LOR) during the epidural needle insertion. The aim of this paper is to illustrate an innovative and non-invasive system able to monitor the pressure exerted during the epidural blockade procedure in order to detect the LOR. The system is based on a Force Sensing Resistor (FSR) sensor arranged on the top of the syringe's plunger. Such a sensor is able to register the resistance opposed to the needle by the different tissues transducing the pressure exerted on the plunger into a change of an electrical resistance. Hence, on the base of a peculiar algorithm, the system automatically detects LOR providing visual and acoustic feedbacks to the operator improving the safety of the procedure. Experiments have been performed to characterize the measurement device and to validate the whole system. Notice that the proposed solution is able to perform an effective detection of the LOR.

  11. MEMS acoustic emission transducers designed with high aspect ratio geometry

    NASA Astrophysics Data System (ADS)

    Saboonchi, H.; Ozevin, D.

    2013-09-01

    In this paper, micro-electro-mechanic systems (MEMS) acoustic emission (AE) transducers are manufactured using an electroplating technique. The transducers use a capacitance change as their transduction principle, and are tuned to the range 50-200 kHz. Through the electroplating technique, a thick metal layer (20 μm nickel + 0.5 μm gold) is used to form a freely moving microstructure layer. The presence of the gold layer reduces the potential corrosion of the nickel layer. A dielectric layer is deposited between the two electrodes, thus preventing the stiction phenomenon. The transducers have a measured quality factor in the range 15-30 at atmospheric pressure and are functional without vacuum packaging. The transducers are characterized using electrical and mechanical tests to identify the capacitance, resonance frequency and damping. Ultrasonic wave generation using a Q-switched laser shows the directivity of the transducer sensitivity. The comparison of the MEMS transducers with similar frequency piezoelectric transducers shows that the MEMS AE transducers have better response characteristics and sensitivity at the resonance frequency and well-defined waveform signatures (rise time and decay time) due to pure resonance behavior in the out-of-plane direction. The transducers are sensitive to a unique wave direction, which can be utilized to increase the accuracy of source localization by selecting the correct wave velocity at the structures.

  12. High Temperature Ultrasonic Transducer for Real-time Inspection

    NASA Astrophysics Data System (ADS)

    Amini, Mohammad Hossein; Sinclair, Anthony N.; Coyle, Thomas W.

    A broadband ultrasonic transducer with a novel porous ceramic backing layer is introduced to operate at 700 °C. 36° Y-cut lithium niobate (LiNbO3) single crystal was selected for the piezoelectric element. By appropriate choice of constituent materials, porosity and pore size, the acoustic impedance and attenuation of a zirconia-based backing layer were optimized. An active brazing alloy with high temperature and chemical stability was selected to bond the transducer layers together. Prototype transducers have been tested at temperatures up to 700 °C. The experiments confirmed that transducer integrity was maintained.

  13. Radiation endurance of piezoelectric ultrasonic transducers--a review.

    PubMed

    Sinclair, A N; Chertov, A M

    2015-03-01

    A literature survey is presented on the radiation endurance of piezoelectric ultrasonic transducer components and complete transducer assemblies, as functions of cumulative gamma dose and neutron fluence. The most extensive data on this topic has been acquired in CANDU electrical generating stations, which use piezoelectric ultrasonic transducers manufactured commercially with minor accommodation for high radiation fields. They have been found to be reliable for cumulative gamma doses of up to approximately 2 MegaGrays; a brief summary is made of the associated accommodations required to the transducer design, and the ultimate expected failure modes. Outside of the CANDU experience, endurance data have been acquired under a diverse spectrum of operating conditions; this can impede a direct comparison of the information from different sources. Much of this data is associated with transducers immersed in liquid metal coolants associated with advanced reactor designs. Significant modifications to conventional designs have led to the availability of custom transducers that can endure well over 100 MegaGrays of cumulative gamma dose. Published data on transducer endurance against neutron fluence are reviewed, but are either insufficient, or were reported with inadequate description of test conditions, to make general conclusions on transducer endurance with high confidence. Several test projects are planned or are already underway by major laboratories and research consortia to augment the store of transducer endurance data with respect to both gamma and neutron radiation.

  14. Ultrasound probe and needle-guide calibration for robotic ultrasound scanning and needle targeting.

    PubMed

    Kim, Chunwoo; Chang, Doyoung; Petrisor, Doru; Chirikjian, Gregory; Han, Misop; Stoianovici, Dan

    2013-06-01

    Image-to-robot registration is a typical step for robotic image-guided interventions. If the imaging device uses a portable imaging probe that is held by a robot, this registration is constant and has been commonly named probe calibration. The same applies to probes tracked by a position measurement device. We report a calibration method for 2-D ultrasound probes using robotic manipulation and a planar calibration rig. Moreover, a needle guide that is attached to the probe is also calibrated for ultrasound-guided needle targeting. The method is applied to a transrectal ultrasound (TRUS) probe for robot-assisted prostate biopsy. Validation experiments include TRUS-guided needle targeting accuracy tests. This paper outlines the entire process from the calibration to image-guided targeting. Freehand TRUS-guided prostate biopsy is the primary method of diagnosing prostate cancer, with over 1.2 million procedures performed annually in the U.S. alone. However, freehand biopsy is a highly challenging procedure with subjective quality control. As such, biopsy devices are emerging to assist the physician. Here, we present a method that uses robotic TRUS manipulation. A 2-D TRUS probe is supported by a 4-degree-of-freedom robot. The robot performs ultrasound scanning, enabling 3-D reconstructions. Based on the images, the robot orients a needle guide on target for biopsy. The biopsy is acquired manually through the guide. In vitro tests showed that the 3-D images were geometrically accurate, and an image-based needle targeting accuracy was 1.55 mm. These validate the probe calibration presented and the overall robotic system for needle targeting. Targeting accuracy is sufficient for targeting small, clinically significant prostatic cancer lesions, but actual in vivo targeting will include additional error components that will have to be determined.

  15. Highly reliable multisensor array (MSA) smart transducers

    NASA Astrophysics Data System (ADS)

    Perotti, José; Lucena, Angel; Mackey, Paul; Mata, Carlos; Immer, Christopher

    2006-05-01

    Many developments in the field of multisensor array (MSA) transducers have taken place in the last few years. Advancements in fabrication technology, such as Micro-Electro-Mechanical Systems (MEMS) and nanotechnology, have made implementation of MSA devices a reality. NASA Kennedy Space Center (KSC) has been developing this type of technology because of the increases in safety, reliability, and performance and the reduction in operational and maintenance costs that can be achieved with these devices. To demonstrate the MSA technology benefits, KSC quantified the relationship between the number of sensors (N) and the associated improvement in sensor life and reliability. A software algorithm was developed to monitor and assess the health of each element and the overall MSA. Furthermore, the software algorithm implemented criteria on how these elements would contribute to the MSA-calculated output to ensure required performance. The hypothesis was that a greater number of statistically independent sensor elements would provide a measurable increase in measurement reliability. A computer simulation was created to answer this question. An array of N sensors underwent random failures in the simulation and a life extension factor (LEF equals the percentage of the life of a single sensor) was calculated by the program. When LEF was plotted as a function of N, a quasiexponential behavior was detected with marginal improvement above N = 30. The hypothesis and follow-on simulation results were then corroborated experimentally. An array composed of eight independent pressure sensors was fabricated. To accelerate sensor life cycle and failure and to simulate degradation over time, the MSA was exposed to an environmental tem-perature of 125°C. Every 24 hours, the experiment's environmental temperature was returned to ambient temperature (27°C), and the outputs of all the MSA sensor elements were measured. Once per week, the MSA calibration was verified at five different

  16. Drug injectors and the cleaning of needles and syringes.

    PubMed

    Hughes, R A

    2000-03-01

    When people share needles and syringes they risk transmitting human immunodeficiency virus (HIV) and other infections including hepatitis B virus (HBV) and hepatitis C virus (HCV). Cleaning needles and syringes can help to reduce, although not eliminate, these risks. This article begins by engaging with some of the literature on the cleaning of needles and syringes. Drawing on qualitative research conducted with drug injectors in England, the article then goes on to explore drug injectors' perceptions and experiences of cleaning needles and syringes inside and outside prison. The article concludes by highlighting the implications for future research and policy making. Ultimately there should be a stronger policy response to reduce the risks associated with sharing needles and syringes inside prison, which should include the piloting of prison needle and syringe exchange schemes.

  17. MR-compatible biopsy needle with enhanced tip force sensing

    PubMed Central

    Elayaperumal, Santhi; Bae, Jung Hwa; Christensen, David; Cutkosky, Mark R.; Daniel, Bruce L.; Costa, Joannes M.; Black, Richard J.; Faridian, Fereydoun; Moslehi, Behzad

    2015-01-01

    We describe an instrumented biopsy needle that provides physicians the capability to sense interaction forces directly at the tip of the needle’s inner stylet. The sensors consist of optical fiber Bragg gratings (FBGs), and are unaffected by electromagnetic fields; hence the needle is suitable for MR-guided procedures. In comparison to previous instrumented needles that measure bending strains, the new design has additional sensors and a series of micro-machined holes at the tip. The holes increase strain sensitivity, especially to axial forces, without significantly reducing the stiffness or strength. A comparison of the dynamic forces measured with the new needle and those obtained using a force/torque sensor at the needle base shows that the enhanced tip sensitivity is particularly noticeable when there is significant friction along the needle sleeve. PMID:26509189

  18. Evaluating the advances and use of hypodermic needles in dentistry.

    PubMed

    Boynes, Sean G

    2014-10-01

    Different injection techniques and patient management methodologies have been proposed to decrease the fear patients may have concerning dental needles. Dental providers should have an understanding of the technological advances, changes in techniques, and patient perceptions associated with the hypodermic needle. This article provides an overview of the pain perception process associated with dental injections. It reviews the two main sensory nerve fibers associated with injection pain and discusses needle properties as well as complications and adverse occurrences.

  19. [Pneumothorax following dry needling treatment: legal and ethical aspects].

    PubMed

    Ronconi, Gianpaolo; De Giorgio, Fabio; Ricci, Eleonora; Maggi, Loredana; Spagnolo, Antonio G; Ferrara, Paola Emilia

    2016-01-01

    Trigger point "dry needling" is a technique used to treat myofascial pain. It involves using filiform needles which are inserted into muscles to give local pain relief. Few cases of serious adverse events following this treatment have been reported in the literature. In this paper we describe the case of a professional swimmer who developed pneumothorax after dry needling treatment and discuss the medicolegal and ethical aspects related to competencies and responsibilities of medical doctors and physiotherapists performing the procedure.

  20. Chest Wall Dissemination of Nocardiosis after Percutaneous Transthoracic Needle Biopsy

    SciTech Connect

    Shimamoto, Hiroshi Inaba, Yoshitaka; Yamaura, Hidekazu; Sato, Yozo; Kamiya, Mika; Miyazaki, Masaya; Arai, Yasuaki; Horio, Yoshitsugu

    2007-07-15

    We described a case of chest wall dissemination after percutaneous transthoracic needle biopsy. A 65-year-old man had a lung nodule which was suspected to be lung carcinoma. He underwent percutaneous transthoracic needle biopsy using an 18G semiautomated biopsy needle and pathologic diagnosis showed organizing pneumonia. Two months after the biopsy, chest wall dissemination occurred. Implantation of carcinoma along the biopsy route was suspected, but the mass was actually due to pulmonary nocardiosis.

  1. Vertical positioning surveillance by magnetostrictive transducer

    NASA Astrophysics Data System (ADS)

    Carvalho, A. S.; Lopes, C.; Pinto, O. O.; Nunes, C. D.; Borges, M. F.; Strohaecker, T. R.

    2015-10-01

    This work purpose is to create a positioning automated system of a tailstock to perform impact resistance tests on silicone mammary implants. This system is capable to measure and oversight the positioning through interrelation between three main components: programmable logic controller, human-machine interface and magnetostrictive transducer. Together, these components form an operational closed loop that ensures an appropriate positioning for the impact device. The paper describes how the closed loop works and also the algorithm implemented in the programmable logic controller which surveys the positioning. As a last topic, the paper presents the operator work on the machine's operation in conjunction with human-machine interface. The results were satisfactory and in accordance with the limits determined on ABNT NBR ISO 14607 for this method of tests.

  2. Catheter tip force transducer for cardiovascular research

    NASA Technical Reports Server (NTRS)

    Feldstein, C.; Lewis, G. W.; Silver, R. H.; Culler, V. H. (Inventor)

    1976-01-01

    A force transducer for measuring dynamic force activity within the heart of a subject essentially consists of a U-shaped beam of low elastic compliance material. Two lines extend from the beams's legs and a long coil spring is attached to the beam. A strain gauge is coupled to one of the beam's legs to sense deflections thereof. The beam with the tines and most of the spring are surrounded by a flexible tube, defining a catheter, which is insertable into a subject's heart through an appropriate artery. The tines are extractable from the catheter for implantation into the myocardium by pushing on the end of the spring which extends beyond the external end of the catheter.

  3. Optically selective, acoustically resonant gas detecting transducer

    NASA Technical Reports Server (NTRS)

    Dimeff, J. (Inventor)

    1977-01-01

    A gas analyzer is disclosed which responds to the resonant absorption or emission spectrum of a specific gas by producing an acoustic resonance in a chamber containing a sample of that gas, and which measures the amount of that emission or absorption by measuring the strength of that acoustic resonance, e.g., the maximum periodic pressure, velocity or density achieved. In the preferred embodiment, a light beam is modulated periodically at the acoustical resonance frequency of a closed chamber which contains an optically dense sample of the gas of interest. Periodic heating of the absorbing gas by the light beam causes a cyclic expansion, movement, and pressure within the gas. An amplitude is reached where the increased losses were the cyclic radiation energy received. A transducing system is inclined for converting the pressure variations of the resonant gas into electronic readout signals.

  4. Acoustic transducer based on dielectric elastomers

    NASA Astrophysics Data System (ADS)

    Graf, Christian; Maas, Jügen

    2012-04-01

    Dielectric electroactive polymers are thin films based on elastomeric material coated with compliant and conductive electrodes. By applying an electrical field, the polymer performs large deformations, which can be utilized to generate sound waves. When using such kind of electrostatic loudspeakers, no additional resonating sound boxes are required and the vibrating mass is very lightweight, resulting in an excellent impulse and wide-band frequency response. For the loudspeaker's operation both an electrical bias voltage and a mechanical bias stress have to be applied. In this contribution different possibilities are presented to generate the mechanical bias stress. The design of an appropriate power electronics for the acoustic transducer, which is build of standard components, is also described. Finally, the loudspeaker concepts are evaluated by experiments in an anechoic room.

  5. Torsional ultrasonic transducer computational design optimization.

    PubMed

    Melchor, J; Rus, G

    2014-09-01

    A torsional piezoelectric ultrasonic sensor design is proposed in this paper and computationally tested and optimized to measure shear stiffness properties of soft tissue. These are correlated with a number of pathologies like tumors, hepatic lesions and others. The reason is that, whereas compressibility is predominantly governed by the fluid phase of the tissue, the shear stiffness is dependent on the stroma micro-architecture, which is directly affected by those pathologies. However, diagnostic tools to quantify them are currently not well developed. The first contribution is a new typology of design adapted to quasifluids. A second contribution is the procedure for design optimization, for which an analytical estimate of the Robust Probability Of Detection, called RPOD, is presented for use as optimality criteria. The RPOD is formulated probabilistically to maximize the probability of detecting the least possible pathology while minimizing the effect of noise. The resulting optimal transducer has a resonance frequency of 28 kHz.

  6. The biopolitics of needle exchange in the United States

    PubMed Central

    McLean, Katherine

    2012-01-01

    Needle exchange began in the United States as a fragmented and illegal practice initiated by actors at the grassroots level; since the late 1980s, needle exchange has achieved increasing yet variable levels of institutional support across the country, receiving official sanction and funding from state and municipal governments. In turn, the practice(s) and discourse(s) of needle exchange have shifted significantly in many locales, becoming the purview of professional administration that advocates needle exchange as a necessary public health measure. This article is interested in the ways in which needle exchange has become implicated in and appropriated by networks of power seeking to discipline and regulate injection drug use. Drawing theoretically on Michel Foucault’s writings concerning biopower and governmentality, it will examine the proliferation of discourses, knowledges, and rules surrounding needle exchange in the United States. At the same time, this article will avoid a characterization of needle exchange that envisions the unilateral control of drug users by governmental power, illuminating instead both its negative and productive effects for drug users. Namely, it will explore how needle exchange creates both subjects of interest and subjects of resistance among drug users – that is to say, the governmentalization of needle exchange and its ‘clients’. PMID:22389572

  7. Lab in a needle for epidural space identification

    NASA Astrophysics Data System (ADS)

    Carotenuto, B.; Micco, A.; Ricciardi, A.; Amorizzo, E.; Mercieri, M.; Cutolo, A.; Cusano, A.

    2016-05-01

    This work relies on the development of a sensorized medical needle with an all-optical guidance (Lab in a Needle) system for epidural space identification. The device is based on the judicious integration of a Fiber Bragg grating sensor inside the lumen of an epidural needle to discriminate between different types of tissue and thus providing continuous and real time measurements of the pressure experienced by the needle tip during its advancement. Experiments carried out on an epidural training phantom demonstrate the validity of our approach for the correct and effective identification of the epidural space.

  8. Thermal dispersion method for an ultrasonic phased-array transducer

    NASA Astrophysics Data System (ADS)

    Choi, Euna; Lee, Wonseok; Roh, Yongrae

    2016-07-01

    When the driving voltage of an ultrasonic transducer is increased to improve the quality of ultrasound images, heat is generated inside the transducer, which can burn the patient’s skin and degrade transducer performance. In this study, the method to disperse the heat inside an ultrasonic phased-array transducer has been examined. The mechanism of temperature rise due to heat generation inside the transducer was investigated by numerical analysis and the effects of the thermal properties of the components of the transducer such as specific heat and thermal conductivity on the temperature rise were analyzed. On the basis of the results, a heat-dispersive structure was devised to reduce the temperature at the surface of the acoustic lens of the transducer. Prototype transducers were fabricated to check the efficacy of the heat-dispersive structure. By experiments, we have confirmed that the new heat-dispersive structure can reduce the internal temperature by as much as 50% in comparison with the conventional structure, which confirms the validity of the thermal dispersion mechanism developed in this work.

  9. 40 CFR 1066.240 - Torque transducer verification and calibration.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Torque transducer verification and...) AIR POLLUTION CONTROLS VEHICLE-TESTING PROCEDURES Dynamometer Specifications § 1066.240 Torque transducer verification and calibration. Calibrate torque-measurement systems as described in 40 CFR 1065.310....

  10. 40 CFR 1066.240 - Torque transducer verification.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Torque transducer verification. 1066... POLLUTION CONTROLS VEHICLE-TESTING PROCEDURES Dynamometer Specifications § 1066.240 Torque transducer verification. Verify torque-measurement systems by performing the verifications described in §§ 1066.270...

  11. 40 CFR 1066.240 - Torque transducer verification and calibration.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Torque transducer verification and...) AIR POLLUTION CONTROLS VEHICLE-TESTING PROCEDURES Dynamometer Specifications § 1066.240 Torque transducer verification and calibration. Calibrate torque-measurement systems as described in 40 CFR 1065.310....

  12. A dynamic calibration method for the pressure transducer

    NASA Astrophysics Data System (ADS)

    Wang, Zhongyu; Wang, Zhuoran; Li, Qiang

    2016-01-01

    Pressure transducer is widely used in the field of industry. A calibrated pressure transducer can increase the performance of precision instruments in the closed mechanical relationship. Calibration is the key to ensure the pressure transducer with a high precision and dynamic characteristic. Unfortunately, the current calibration method can usually be used in the laboratory with a good condition and only one pressure transducer can be calibrated at each time. Therefore the calibration efficiency is hard to meet the requirement of modern industry with high efficiency. A dynamic and fast calibration technology with a calibration device and a corresponding data processing method is proposed in this paper. Firstly, the pressure transducer to be calibrated is placed in the small cavity chamber. The calibration process only contains a single loop. The outputs of each calibrated transducer are recorded automatically by the control terminal. Secondly, LabView programming is used for the information acquisition and data processing. The performance of the repeatability and nonlinear indicators can be figured out directly. At last the pressure transducers are calibrated simultaneously in the experiment to verify the suggested calibration technology. The experimental result shows this method can be used to calibrate the pressure transducer in the practical engineering measurement.

  13. 21 CFR 868.2885 - Gas flow transducer.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Gas flow transducer. 868.2885 Section 868.2885 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2885 Gas flow transducer....

  14. How to design and construct multielement ultrasonic transducers

    NASA Astrophysics Data System (ADS)

    Burrier, R. A.; Claus, R. O.

    The practical 'how to' design and construction of multielement ultrasonic transducers are described. First, design procedures based on direct calculations of the desired acoustic field are reviewed. Second, techniques for implementing these designs using piezoelectric active elements are discussed. Finally, optical and acoustic test methods for transducer calibration are indicated.

  15. Metal cap flexural transducers for air-coupled ultrasonics

    NASA Astrophysics Data System (ADS)

    Eriksson, T. J. R.; Dixon, S.; Ramadas, S. N.

    2015-03-01

    Ultrasonic generation and detection in fluids is inefficient due to the large difference in acoustic impedance between the piezoelectric element and the propagation medium, leading to large internal reflections and energy loss. One way of addressing the problem is to use a flexural transducer, which uses the bending modes in a thin plate or membrane. As the plate bends, it displaces the medium in front of it, hence producing sound waves. A piezoelectric flexural transducer can generate large amplitude displacements in fluid media for relatively low excitation voltages. Commercially available flexural transducers for air applications operate at 40 kHz, but there exists ultrasound applications that require significantly higher frequencies, e.g. flow measurements. Relatively little work has been done to date to understand the underlying physics of the flexural transducer, and hence how to design it to have specific properties suitable for particular applications. This paper investigates the potential of the flexural transducer and its operating principles. Two types of actuation methods are considerd: piezoelectric and electrodynamic. The piezoelectrically actuated transducer is more energy efficient and intrinsically safe, but the electrodynamic transducer has the advantage of being less sensitive to high temperature environments. The theory of vibrating plates is used to predict transducer frequency in addition to front face amplitude, which shows good correlation with experimental results.

  16. Respiratory Belt Transducer Constructed Using a Singing Greeting Card Beeper

    ERIC Educational Resources Information Center

    Bhaskar, Anand; Subramani, Selvam; Ojha, Rajdeep

    2013-01-01

    An article by Belusic and Zupancic described the construction of a finger pulse sensor using a singing greeting card beeper. These authors felt that this beeper made of piezoelectric material could be easily modified to function as a respiratory belt transducer to monitor respiratory movements. Commercially available respiratory belt transducers,…

  17. Resonant acoustic transducer system for a well drilling string

    DOEpatents

    Kent, William H.; Mitchell, Peter G.

    1981-01-01

    For use in transmitting acoustic waves propagated along a well drilling string, a piezoelectric transducer is provided operating in the relatively low loss acoustic propagation range of the well drilling string. The efficiently coupled transmitting transducer incorporates a mass-spring-piezoelectric transmitter combination permitting resonant operation in the desired low frequency range.

  18. Resonant acoustic transducer system for a well drilling string

    DOEpatents

    Nardi, Anthony P.

    1981-01-01

    For use in transmitting acoustic waves propated along a well drilling string, a piezoelectric transducer is provided operating in the relatively low loss acoustic propagation range of the well drilling string. The efficiently coupled transmitting transducer incorporates a mass-spring-piezoelectric transmitter combination permitting a resonant operation in the desired low frequency range.

  19. A Force Transducer from a Junk Electronic Balance

    ERIC Educational Resources Information Center

    Aguilar, Horacio Munguia; Aguilar, Francisco Armenta

    2009-01-01

    It is shown how the load cell from a junk electronic balance can be used as a force transducer for physics experiments. Recovering this device is not only an inexpensive way of getting a valuable laboratory tool but also very useful didactic work on electronic instrumentation. Some experiments on mechanics with this transducer are possible after a…

  20. Dynamics Characterisation of Cymbal Transducers for Power Ultrasonics Applications

    NASA Astrophysics Data System (ADS)

    Feeney, Andrew; Bejarano, Fernando; Lucas, Margaret

    A class V cymbal flextensional transducer is composed of a piezoceramic disc sandwiched between two cymbal-shaped shell end-caps. Depending on the type of piezoceramic, there exists a maximum voltage that can be reached without depolarisation, but also, at higher voltage levels, amplitude saturation can occur. In addition, there is a restriction imposed by the mechanical strength of the bonding agent. The effects of input voltage level on the vibration response of two cymbal transducers are studied. The first cymbal transducer has a standard configuration of end-caps bonded to a piezoceramic disc, whereas the second cymbal transducer is a modified design which includes a metal ring to improve the mechanical coupling with the end-caps, to enable the transducer to operate at higher voltages, thereby generating higher displacement amplitudes. This would allow the transducer to be suitable for power ultrasonics applications. Furthermore, the input voltages to each transducer are increased incrementally to determine the linearity in the dynamic responses. Through a combination of numerical modelling and experiments, it is shown how the improved mechanical coupling in the modified cymbal transducer allows higher vibration amplitudes to be reached.

  1. How to design and construct multielement ultrasonic transducers

    NASA Technical Reports Server (NTRS)

    Burrier, R. A.; Claus, R. O.

    1984-01-01

    The practical 'how to' design and construction of multielement ultrasonic transducers are described. First, design procedures based on direct calculations of the desired acoustic field are reviewed. Second, techniques for implementing these designs using piezoelectric active elements are discussed. Finally, optical and acoustic test methods for transducer calibration are indicated.

  2. Thinking ethically about needle and syringe programs.

    PubMed

    Kleinig, John

    2006-01-01

    Accepting-for the sake of argument-our current legal policies concerning heroin use and its users, what ethical questions are raised for needle and syringe program (NSPs)? Do they weaken drug laws, send the wrong message or obscure the right message, do little to eliminate the harm of drugs, detract from alternatives, and/or constitute a counsel of despair? I suggest that in the absence of established better alternatives, NSPs constitute a morally acceptable and in some cases even desirable option despite the continued criminalization of injecting drug use. Yet they must be conceived and administered in ways that do not reinforce prevailing social prejudices.

  3. Airborne Transducer Integrity under Operational Environment for Structural Health Monitoring.

    PubMed

    Salmanpour, Mohammad Saleh; Sharif Khodaei, Zahra; Aliabadi, Mohammad Hossein

    2016-12-12

    This paper investigates the robustness of permanently mounted transducers used in airborne structural health monitoring systems, when exposed to the operational environment. Typical airliners operate in a range of conditions, hence, structural health monitoring (SHM) transducer robustness and integrity must be demonstrated for these environments. A set of extreme temperature, altitude and vibration environment test profiles are developed using the existing Radio Technical Commission for Aeronautics (RTCA)/DO-160 test methods. Commercially available transducers and manufactured versions bonded to carbon fibre reinforced polymer (CFRP) composite materials are tested. It was found that the DuraAct transducer is robust to environmental conditions tested, while the other transducer types degrade under the same conditions.

  4. Ultrasonic phased array transducers for nondestructive evaluation of steel structures

    NASA Astrophysics Data System (ADS)

    Song, Sung-Jin; Shin, Hyeon Jae; Jang, You Hyun

    2000-05-01

    An ultrasonic phased array transducer has been developed and demonstrated for the nondestructive evaluation of steel structures. The number of array elements is 64 and the center frequency is about 5 MHz. This phased array transducer is designed to use with the phased array system that does steering, transmission focusing and dynamic receive focusing. Each of the array elements is individually excited according to the focal laws and steering angles. Measurements of ultrasonic beam profiles for the array transducer in a reference steel block are presented and compared with theoretical predictions. Some of the phased array transducer design concepts for the application in steel structures are discussed. The two-dimensional ultrasonic images of the sample steel block including flat bottom holes and side drilled holes are presented. Experimental and theoretical results demonstrate excellent feasibility of the utility of the phased array transducer in imaging and detection of defects in steel structures.

  5. Piezoelectric single crystals for ultrasonic transducers in biomedical applications

    PubMed Central

    Zhou, Qifa; Lam, Kwok Ho; Zheng, Hairong; Qiu, Weibao; Shung, K. Kirk

    2014-01-01

    Piezoelectric single crystals, which have excellent piezoelectric properties, have extensively been employed for various sensors and actuators applications. In this paper, the state–of–art in piezoelectric single crystals for ultrasonic transducer applications is reviewed. Firstly, the basic principles and design considerations of piezoelectric ultrasonic transducers will be addressed. Then, the popular piezoelectric single crystals used for ultrasonic transducer applications, including LiNbO3 (LN), PMN–PT and PIN–PMN–PT, will be introduced. After describing the preparation and performance of the single crystals, the recent development of both the single–element and array transducers fabricated using the single crystals will be presented. Finally, various biomedical applications including eye imaging, intravascular imaging, blood flow measurement, photoacoustic imaging, and microbeam applications of the single crystal transducers will be discussed. PMID:25386032

  6. Frequency response calibration of recess-mounted pressure transducers

    NASA Astrophysics Data System (ADS)

    Marcolini, M. A.; Lorber, P. F.; Miller, W. T., Jr.; Covino, A. F., Jr.

    1991-03-01

    A technique is described for measuring the frequency response of pressure transducers mounted inside a model, where a narrow pipette leads to an orifice at the surface. An acoustic driver is mounted to a small chamber which has an opening at the opposite end with an O-ring seal to place over the orifice. A 3.18 mm (1/8 inch) reference microphone is mounted to one side of the chamber. The acoustic driver receives an input of white noise, and the transducer and reference microphone outputs are compared to obtain the frequency response of the pressure transducer. Selected results are presented in the form of power spectra for both the transducer and the reference, as well as the amplitude variation and phase shift between the two signals as a function of frequency. The effect of pipette length and the use of this technique for identifying both blocked orifices and faulty transducers are described.

  7. Frequency response calibration of recess-mounted pressure transducers

    NASA Technical Reports Server (NTRS)

    Marcolini, M. A.; Lorber, P. F.; Miller, W. T., Jr.; Covino, A. F., Jr.

    1991-01-01

    A technique is described for measuring the frequency response of pressure transducers mounted inside a model, where a narrow pipette leads to an orifice at the surface. An acoustic driver is mounted to a small chamber which has an opening at the opposite end with an O-ring seal to place over the orifice. A 3.18 mm (1/8 inch) reference microphone is mounted to one side of the chamber. The acoustic driver receives an input of white noise, and the transducer and reference microphone outputs are compared to obtain the frequency response of the pressure transducer. Selected results are presented in the form of power spectra for both the transducer and the reference, as well as the amplitude variation and phase shift between the two signals as a function of frequency. The effect of pipette length and the use of this technique for identifying both blocked orifices and faulty transducers are described.

  8. Embedded Ultrasonic Transducers for Active and Passive Concrete Monitoring

    PubMed Central

    Niederleithinger, Ernst; Wolf, Julia; Mielentz, Frank; Wiggenhauser, Herbert; Pirskawetz, Stephan

    2015-01-01

    Recently developed new transducers for ultrasonic transmission, which can be embedded right into concrete, are now used for non-destructive permanent monitoring of concrete. They can be installed during construction or thereafter. Large volumes of concrete can be monitored for changes of material properties by a limited number of transducers. The transducer design, the main properties as well as installation procedures are presented. It is shown that compressional waves with a central frequency of 62 kHz are mainly generated around the transducer’s axis. The transducer can be used as a transmitter or receiver. Application examples demonstrate that the transducers can be used to monitor concrete conditions parameters (stress, temperature, …) as well as damages in an early state or the detection of acoustic events (e.g., crack opening). Besides application in civil engineering our setups can also be used for model studies in geosciences. PMID:25923928

  9. Durability investigation of a group of strain gage pressure transducers

    NASA Technical Reports Server (NTRS)

    Lederer, P. S.; Hilten, J. S.

    1972-01-01

    A durability investigation was conducted on a group of eighteen bonded-wire strain gage pressure transducers with ranges of 0 to 15 psig and 0 to 100 psig using an improved version of a previously developed technique. Some of the transducers were subjected to 40 million pressure cycles at a 5-Hz rate at laboratory ambient conditions, others were cycled at a temperature of 150 F (65.6 C). The largest change in sensitivity observed was 0.22% for a 100-psig transducer subjected to 40 million pressure cycles at 150 F. The largest change in zero pressure output observed was 0.91% FS for the same transducer. None of the transducers failed completely as a result of cycling at or below full scale pressure.

  10. Piezoelectric single crystals for ultrasonic transducers in biomedical applications.

    PubMed

    Zhou, Qifa; Lam, Kwok Ho; Zheng, Hairong; Qiu, Weibao; Shung, K Kirk

    2014-10-01

    Piezoelectric single crystals, which have excellent piezoelectric properties, have extensively been employed for various sensors and actuators applications. In this paper, the state-of-art in piezoelectric single crystals for ultrasonic transducer applications is reviewed. Firstly, the basic principles and design considerations of piezoelectric ultrasonic transducers will be addressed. Then, the popular piezoelectric single crystals used for ultrasonic transducer applications, including LiNbO3 (LN), PMN-PT and PIN-PMN-PT, will be introduced. After describing the preparation and performance of the single crystals, the recent development of both the single-element and array transducers fabricated using the single crystals will be presented. Finally, various biomedical applications including eye imaging, intravascular imaging, blood flow measurement, photoacoustic imaging, and microbeam applications of the single crystal transducers will be discussed.

  11. Airborne Transducer Integrity under Operational Environment for Structural Health Monitoring

    PubMed Central

    Salmanpour, Mohammad Saleh; Sharif Khodaei, Zahra; Aliabadi, Mohammad Hossein

    2016-01-01

    This paper investigates the robustness of permanently mounted transducers used in airborne structural health monitoring systems, when exposed to the operational environment. Typical airliners operate in a range of conditions, hence, structural health monitoring (SHM) transducer robustness and integrity must be demonstrated for these environments. A set of extreme temperature, altitude and vibration environment test profiles are developed using the existing Radio Technical Commission for Aeronautics (RTCA)/DO-160 test methods. Commercially available transducers and manufactured versions bonded to carbon fibre reinforced polymer (CFRP) composite materials are tested. It was found that the DuraAct transducer is robust to environmental conditions tested, while the other transducer types degrade under the same conditions. PMID:27973450

  12. Study on the broadband tonpilz transducer with a single hole.

    PubMed

    Xiping, He; Jing, Hu

    2009-05-01

    To get a wide-band transducer, the piezoelectric sandwiched transducer with a frustum hole in its head piece is presented in this paper. The equivalent circuit is derived, and the expressions of the equivalent mass and the equivalent impedance of the transducer are obtained by using one-dimensional (1D) design theory. Moreover, the expressions of the mechanical quality factor and the frequency bandwidth are obtained and the transmitting voltage response of the transducer is calculated by using finite element method. The theoretical results show that the frequency bandwidth of the transducer with a hole is wider than that without a hole when their resonant frequencies are almost equal. The tested results are in good agreement with the theoretical calculations.

  13. Three-dimensional needle-tip localization by electric field potential and camera hybridization for needle electromyography exam robotic simulator

    PubMed Central

    He, Siyu; Gomez-Tames, Jose; Yu, Wenwei

    2016-01-01

    As one of neurological tests, needle electromygraphy exam (NEE) plays an important role to evaluate the conditions of nerves and muscles. Neurology interns and novice medical staff need repetitive training to improve their skills in performing the exam. However, no training systems are able to reproduce multiple pathological conditions to simulate real needle electromyogram exam. For the development of a robotic simulator, three components need to be realized: physical modeling of upper limb morphological features, position-dependent electromyogram generation, and needle localization; the latter is the focus of this study. Our idea is to couple two types of sensing mechanism in order to acquire the needle-tip position with high accuracy. One is to segment the needle from camera images and calculate its insertion point on the skin surface by a top-hat transform algorithm. The other is voltage-based depth measurement, in which a conductive tissue-like phantom was used to realize both needle-tip localization and physical sense of needle insertion. For that, a pair of electrodes was designed to generate a near-linear voltage distribution along the depth direction of the tissue-like phantom. The accuracy of the needle-tip position was investigated by the electric field potential and camera hybridization. The results showed that the needle tip could be detected with an accuracy of 1.05±0.57 mm. PMID:27382339

  14. A new needle on the block: EchoTip ProCore endobronchial ultrasound needle

    PubMed Central

    Dincer, H Erhan; Andrade, Rafael; Zamora, Felix; Podgaetz, Eitan

    2016-01-01

    Endobronchial ultrasound has become the first choice standard of care procedure to diagnose benign or malignant lesions involving mediastinum and lung parenchyma adjacent to the airways owing to its characteristics of being real-time and minimally invasive. Although the incidence of lung cancer has been decreasing, it is and will be the leading cause of cancer-related mortality in the next few decades. When compared to other cancers, lung cancer kills more females than breast and colon cancers combined and more males than colon and prostate cancers combined. The type of lung cancer has changed in recent decades and adenocarcinoma has become the most frequent cell type. Prognosis of lung cancer depends upon the cell type and the staging at the time of diagnosis. The cell type and molecular characteristics of adenocarcinoma may allow individualized targeted treatment. Other malignant conditions in the mediastinum and lung (eg, metastatic lung cancers and lymphoma) can be biopsied using endobronchial ultrasound needles. Endobronchial ultrasound needle biopsies provides mostly cytology specimens due to its small sizes of needles (22 gauge or larger) which may not give enough tissue to make a definitive diagnosis in malignant (eg, lymphoma) or benign conditions (eg, sarcoidosis). EchoTip ProCore endobronchial needle released in early 2014 provides histologic biopsy material. Larger tissue biopsies may potentially provide a higher diagnostic yield and it eliminates mediastinoscopy or other surgical interventions. Here we aim to review bronchoscopic approach in the diagnosis of mediastinal lesions with emphasis of EchoTip ProCore needles. PMID:27099535

  15. Preschool Needle Pain Responding: Establishing 'Normal'.

    PubMed

    Waxman, Jordana A; DiLorenzo, Miranda G; Pillai Riddell, Rebecca R; Flora, David B; Greenberg, Saul; Garfield, Hartley

    2017-02-11

    The current study sets forth to provide both descriptive data for preschool vaccination pain responding and examine longitudinal relationships over early childhood. Growth mixture modeling (GMM) was first used to describe stable subgroups of preschoolers based on their pain response patterns over 2-minutes post-needle. Secondly, a parallel-process growth curve model was used to assess the stability of acute pain responding from 12-months of age to preschool age. Specifically, we examined whether preschool pain-related distress or regulation could be predicted from 12-month acute pain responding. Preschool participants were part of a Canadian longitudinal cohort (The OUCH Cohort; N = 302). GMM analyses discerned 3 distinct groups of preschoolers, with an important minority not regulating to low-no pain by 2 minutes post-needle. There were no significant associations between 12-month and preschool pain responding. These results highlight the steep trajectory of development between these different stages of early childhood and the variability of pain responding at the preschool vaccination.

  16. Cryosurgery and needle ablation of renal lesions.

    PubMed

    Johnson, D B; Nakada, S Y

    2001-05-01

    Laparoscopic renal cryoablation is a minimally invasive alternative for treating renal tumors utilizing narrow probes cooled with a compressed gas such as argon or carbon dioxide. At this time, cryotherapy has shown the most promise as an alternative to partial nephrectomy as a nephron-sparing treatment for renal tumors. Radiofrequency ablation employs needle electrodes placed percutaneously directly into renal lesions to deliver energy, creating high temperatures leading to cell death. High-intensity focused ultrasound is a noninvasive technique in which focused ultrasound energy is applied to cause cell death within the focal zone. Microwave thermotherapy uses small applicators to deliver microwave energy to tissues, resulting in the generation of heat. Although RF, HIFU, and microwave thermotherapy show promise as energy sources for tumor ablation, they are in the early stages of development. Little is known about their acute and chronic histologic effects and long-term efficacy as a treatment for malignant disease. Further work is needed to develop cryosurgery and needle ablation in order to delineate what role these techniques will ultimately play in the management of RCC.

  17. Sensorless Motion Planning for Medical Needle Insertion in Deformable Tissues

    PubMed Central

    Alterovitz, Ron; Goldberg, Kenneth Y.; Pouliot, Jean; Hsu, I-Chow

    2009-01-01

    Minimally invasive medical procedures such as biopsies, anesthesia drug injections, and brachytherapy cancer treatments require inserting a needle to a specific target inside soft tissues. This is difficult because needle insertion displaces and deforms the surrounding soft tissues causing the target to move during the procedure. To facilitate physician training and preoperative planning for these procedures, we develop a needle insertion motion planning system based on an interactive simulation of needle insertion in deformable tissues and numerical optimization to reduce placement error. We describe a 2-D physically based, dynamic simulation of needle insertion that uses a finite-element model of deformable soft tissues and models needle cutting and frictional forces along the needle shaft. The simulation offers guarantees on simulation stability for mesh modications and achieves interactive, real-time performance on a standard PC. Using texture mapping, the simulation provides visualization comparable to ultrasound images that the physician would see during the procedure. We use the simulation as a component of a sensorless planning algorithm that uses numerical optimization to compute needle insertion offsets that compensate for tissue deformations. We apply the method to radioactive seed implantation during permanent seed prostate brachytherapy to minimize seed placement error. PMID:19126473

  18. Synthesis of nano-crystalline multifibrous zirconia needle

    SciTech Connect

    Biswas, Mridula; Bandyopadhyay, Siddhartha

    2013-06-01

    Graphical abstract: - Highlights: • Zirconia needles have been successfully prepared by simple inorganic sol–gel route. • The shape of the needles was retained after firing with aspect ratio > 400. • Needles are composed of multiple fibres. • Fibres are composed of nano crystals. - Abstract: Zirconia needles have been successfully synthesized using a simple inorganic sol–gel process without using any template. The method employs mixture of zirconium oxychloride octahydrate and sulphuric acid in aqueous medium. This process requires heat treatment at 40 °C for 2 h in an oven for nucleus formation. Complete formation of needle occurs after 17 days. The green needle retained its original shape after calcination at 1200 °C. Fired needles were of 1–2 cm in length and 5–50 μm in diameter and possess monoclinic phase. Needles are composed of multiple fibres. Depending on the heat treatment temperature, crystallite size varies in the range of 8 to around 300 nm.

  19. Needle Steering in 3-D Via Rapid Replanning

    PubMed Central

    Patil, Sachin; Burgner, Jessica; Webster, Robert J.; Alterovitz, Ron

    2014-01-01

    Steerable needles have the potential to improve the effectiveness of needle-based clinical procedures such as biopsy and drug delivery by improving targeting accuracy and reaching previously inaccessible targets that are behind sensitive or impenetrable anatomical regions. We present a new needle steering system capable of automatically reaching targets in 3-D environments while avoiding obstacles and compensating for real-world uncertainties. Given a specification of anatomical obstacles and a clinical target (e.g., from preoperative medical images), our system plans and controls needle motion in a closed-loop fashion under sensory feedback to optimize a clinical metric. We unify planning and control using a new fast algorithm that continuously replans the needle motion. Our rapid replanning approach is enabled by an efficient sampling-based rapidly exploring random tree (RRT) planner that achieves orders-of-magnitude reduction in computation time compared with prior 3-D approaches by incorporating variable curvature kinematics and a novel distance metric for planning. Our system uses an electromagnetic tracking system to sense the state of the needle tip during the procedure. We experimentally evaluate our needle steering system using tissue phantoms and animal tissue ex vivo. We demonstrate that our rapid replanning strategy successfully guides the needle around obstacles to desired 3-D targets with an average error of less than 3 mm. PMID:25435829

  20. Needle and Syringe Cleaning Practices among Injection Drug Users.

    ERIC Educational Resources Information Center

    Fisher, Dennis G.; Harbke, Colin R.; Canty, John R.; Reynolds, Grace L.

    2002-01-01

    Evaluates the effect of needle exchange on the bleach-mediated disinfection (BMD) practices of 176 needle and syringe sharing injection drug users (IDUs). Results reveal that IDUs who traded sex for money or drugs were less likely to practice BMD, and IDUs who reported a reduced number of sex partners were more likely to practice BMD. (Contains 36…

  1. Design of a Slender Tuned Ultrasonic Needle for Bone Penetration

    NASA Astrophysics Data System (ADS)

    Cleary, Rebecca; Mathieson, Andrew; Wallace, Robert; Simpson, Hamish; Lucas, Margaret

    This paper reports on an ultrasonic bone biopsy needle, particularly focusing on design guidelines applicable for any slender tuned ultrasonic device component. Ultrasonic surgical devices are routinely used to cut a range of biological tissues, such as bone. However the realisation of an ultrasonic bone biopsy needle is particularly challenging. This is due to the requirement to generate sufficient vibrational amplitude capable of penetrating mineralised tissue, while avoiding flexural vibrational responses, which are known to reduce the performance and reliability of slender ultrasonic devices. This investigation uses finite element analysis (FEA) to predict the vibrational behaviour of a resonant needle which has dimensions that match closely to an 8Gx4inch bone marrow biopsy needle. Features of the needle, including changes in material and repeated changes in diameter, have been included and systematically altered to demonstrate that the location of and geometry of these features can significantly affect the resonant frequency of bending and torsional modes of vibration while having a limited effect on the frequency and shape of the tuned longitudinal mode. Experimental modal analysis was used to identify the modal parameters of the selected needle design, validating the FEA model predictions of the longitudinal mode and the close flexural modes. This verifies that modal coupling can be avoided by judicious small geometry modifications. Finally, the tuned needle assembly was driven under typical operational excitation conditions to demonstrate that an ultrasonic biopsy needle can be designed to operate in a purely longitudinal motion.

  2. Needle Steering in 3-D Via Rapid Replanning.

    PubMed

    Patil, Sachin; Burgner, Jessica; Webster, Robert J; Alterovitz, Ron

    2014-08-01

    Steerable needles have the potential to improve the effectiveness of needle-based clinical procedures such as biopsy and drug delivery by improving targeting accuracy and reaching previously inaccessible targets that are behind sensitive or impenetrable anatomical regions. We present a new needle steering system capable of automatically reaching targets in 3-D environments while avoiding obstacles and compensating for real-world uncertainties. Given a specification of anatomical obstacles and a clinical target (e.g., from preoperative medical images), our system plans and controls needle motion in a closed-loop fashion under sensory feedback to optimize a clinical metric. We unify planning and control using a new fast algorithm that continuously replans the needle motion. Our rapid replanning approach is enabled by an efficient sampling-based rapidly exploring random tree (RRT) planner that achieves orders-of-magnitude reduction in computation time compared with prior 3-D approaches by incorporating variable curvature kinematics and a novel distance metric for planning. Our system uses an electromagnetic tracking system to sense the state of the needle tip during the procedure. We experimentally evaluate our needle steering system using tissue phantoms and animal tissue ex vivo. We demonstrate that our rapid replanning strategy successfully guides the needle around obstacles to desired 3-D targets with an average error of less than 3 mm.

  3. Observations on rotating needle insertions using a brachytherapy robot

    NASA Astrophysics Data System (ADS)

    Meltsner, M. A.; Ferrier, N. J.; Thomadsen, B. R.

    2007-09-01

    A robot designed for prostate brachytherapy implantations has the potential to greatly improve treatment success. Much of the research in robotic surgery focuses on measuring accuracy. However, there exist many factors that must be optimized before an analysis of needle placement accuracy can be determined. Some of these parameters include choice of the needle type, insertion velocity, usefulness of the rotating needle and rotation speed. These parameters may affect the force at which the needle interacts with the tissue. A reduction in force has been shown to decrease the compression of the prostate and potentially increase the accuracy of seed position. Rotating the needle as it is inserted may reduce frictional forces while increasing accuracy. However, needle rotations are considered to increase tissue damage due to the drilling nature of the insertion. We explore many of the factors involved in optimizing a brachytherapy robot, and the potential effects each parameter may have on the procedure. We also investigate the interaction of rotating needles in gel and suggest the rotate-cannula-only method of conical needle insertion to minimize any tissue damage while still maintaining the benefits of reduced force and increased accuracy.

  4. Coaxial needle insertion assistant with enhanced force feedback.

    PubMed

    De Lorenzo, Danilo; Koseki, Yoshihiko; De Momi, Elena; Chinzei, Kiyoyuki; Okamura, Allison M

    2013-02-01

    Many medical procedures involving needle insertion into soft tissues, such as anesthesia, biopsy, brachytherapy, and placement of electrodes, are performed without image guidance. In such procedures, haptic detection of changing tissue properties at different depths during needle insertion is important for needle localization and detection of subsurface structures. However, changes in tissue mechanical properties deep inside the tissue are difficult for human operators to sense, because the relatively large friction force between the needle shaft and the surrounding tissue masks the smaller tip forces. A novel robotic coaxial needle insertion assistant, which enhances operator force perception, is presented. This one-degree-of-freedom cable-driven robot provides to the operator a scaled version of the force applied by the needle tip to the tissue, using a novel design and sensors that separate the needle tip force from the shaft friction force. The ability of human operators to use the robot to detect membranes embedded in artificial soft tissue was tested under the conditions of 1) tip force and shaft force feedback, and 2) tip force only feedback. The ratio of successful to unsuccessful membrane detections was significantly higher (up to 50%) when only the needle tip force was provided to the user.

  5. Sensorless motion planning for medical needle insertion in deformable tissues.

    PubMed

    Alterovitz, Ron; Goldberg, Kenneth Y; Pouliot, Jean; Hsu, I-Chow Joe

    2009-03-01

    Minimally invasive medical procedures such as biopsies, anesthesia drug injections, and brachytherapy cancer treatments require inserting a needle to a specific target inside soft tissues. This is difficult because needle insertion displaces and deforms the surrounding soft tissues causing the target to move during the procedure. To facilitate physician training and preoperative planning for these procedures, we develop a needle insertion motion planning system based on an interactive simulation of needle insertion in deformable tissues and numerical optimization to reduce placement error. We describe a 2-D physically based, dynamic simulation of needle insertion that uses a finite-element model of deformable soft tissues and models needle cutting and frictional forces along the needle shaft. The simulation offers guarantees on simulation stability for mesh modifications and achieves interactive, real-time performance on a standard PC. Using texture mapping, the simulation provides visualization comparable to ultrasound images that the physician would see during the procedure. We use the simulation as a component of a sensorless planning algorithm that uses numerical optimization to compute needle insertion offsets that compensate for tissue deformations. We apply the method to radioactive seed implantation during permanent seed prostate brachytherapy to minimize seed placement error.

  6. Spain: government orders distribution of clean needles in prisons.

    PubMed

    2002-03-01

    In a previous issue of the Review we published an article about the positive results of the evaluation of the first needle exchange programs in Spanish prisons. Recently it was reported that Spain's Ministry of the Interior has ordered that sterile needles be distributed in prisons.

  7. Balloon needle for the atraumatic transcortical ventricular approach: technical note.

    PubMed

    Madrazo, I; Franco-Bourland, R; Aguilera, M; Reyes, P; Guízar-Sahagún, G

    1990-03-01

    We have designed a double-lumen inflatable needle for the atraumatic dissection of brain substance. This balloon needle has been successfully used for the ventricular approach in brain grafting procedures to obtain a rounded corticotomy with a diameter of 1.5-2 cm in the treatment of Parkinson's disease.

  8. Long term performance of wearable transducer for motion energy harvesting

    NASA Astrophysics Data System (ADS)

    McGarry, Scott A.; Behrens, Sam

    2010-04-01

    Personal electronic devices such as cell phones, GPS and MP3 players have traditionally depended on battery energy storage technologies for operation. By harvesting energy from a person's motion, these devices may achieve greater run times without increasing the mass or volume of the electronic device. Through the use of a flexible piezoelectric transducer such as poly-vinylidene fluoride (PVDF), and integrating it into a person's clothing, it becomes a 'wearable transducer'. As the PVDF transducer is strained during the person's routine activities, it produces an electrical charge which can then be harvested to power personal electronic devices. Existing wearable transducers have shown great promise for personal motion energy harvesting applications. However, they are presently physically bulky and not ergonomic for the wearer. In addition, there is limited information on the energy harvesting performance for wearable transducers, especially under realistic conditions and for extended cyclic force operations - as would be experienced when worn. In this paper, we present experimental results for a wearable PVDF transducer using a person's measured walking force profile, which is then cycled for a prolonged period of time using an experimental apparatus. Experimental results indicate that after an initial drop in performance, the transducer energy harvesting performance does not substantially deteriorate over time, as less than 10% degradation was observed. Longevity testing is still continuing at CSIRO.

  9. TRANSDUCER GENERATED ARRAYS OF ROBOTIC NANO-ARMS.

    PubMed

    Dolzhenko, Egor; Jonoska, Nataša; Seeman, Nadrian C

    2010-06-01

    We consider sets of two-dimensional arrays, called here transducer generated languages, obtained by iterative applications of transducers (finite state automata with output). Each transducer generates a set of blocks of symbols such that the bottom row of a block is an input string accepted by the transducer and, by iterative application of the transducer, each row of the block is an output of the transducer on the preceding row. We show how these arrays can be implemented through molecular assembly of triple crossover DNA molecules. Such assembly could serve as a scaffold for arranging molecular robotic arms capable for simultaneous movements. We observe that transducer generated languages define a class of languages which is a proper subclass of recognizable picture languages, but it containing the class of all factorial local two-dimensional languages. By taking the average growth rate of the number of blocks in the language as a measure of its complexity, we further observe that arrays with high complexity patterns can be generated in this way.

  10. High-frequency transducers for medical ultrasonic imaging

    NASA Astrophysics Data System (ADS)

    Snook, Kevin A.; Zhao, Jian-Zhong; Alves, Carlos H. F.; Cannata, Jonathan M.; Chen, WoHsing; Meyer, Richard J., Jr.; Ritter, Timothy A.; Shung, K. Kirk

    2000-04-01

    A wide variety of fabrication techniques and materials produce ultrasound transducers with very different performance characteristics. High frequency (50 MHz), focused single element transducers using lead zirconate titanate (PZT) fiber composite, lead titanate (PbTiO3) ceramic, polyvinylidene fluoride (PVDF) polymer and lithium niobate (LiNbO3) single crystal are compared in design and performance. The transducers were all constructed with a 3 mm aperture and f- number of 2 - 3. Design considerations discussed include optimization of designs using different lens, backing and matching materials for acoustic matching and the use of several electrical tuning techniques to match the transducers to the 50(Omega) circuitry. Transducers were tested for insertion loss and -6dB bandwidth using a quartz flat- plate target. Insertion loss measurements between transducers were -20dB to -50dB with bandwidths in the range of 50 - 120%. Through the use of an ultrasound backscatter microscope (UBM), the transducer were compared using in vitro images of the human eye. Images of a wire phantom were also made for comparison of lateral and axial resolution of each device.

  11. Modeling Electric Fields of Peripheral Nerve Block Needles.

    NASA Astrophysics Data System (ADS)

    Davis, James Ch.; Ramirez, Jason G.

    2005-11-01

    Peripheral nerve blocks present an alternative to general anesthesia in certain surgical procedures and a means of acute pain relief through continuous blockades. They have been shown to decrease the incidence of postoperative nausea and vomiting, reduce oral narcotic side effects, and improve sleep quality. Injecting needles, which carry small stimulating currents, are often used to aid in locating the target nerve bundle. With this technique, muscle responses indicate needle proximity to the corresponding nerve bundle. Failure rates in first injection attempts prompted our study of electric field distributions. Finite difference methods were used to solve for the electric fields generated by two widely used needles. Differences in geometry between needles are seen to effect changes in electric field and current distributions. Further investigations may suggest needle modifications that result in a reduction of initial probing failures.

  12. Modeling Electric Fields of Peripheral Nerve Block Needles.

    NASA Astrophysics Data System (ADS)

    Davis, James Ch.; Anderson, Norman E.; Meisel, Mark W.; Ramirez, Jason G.; Kayser Enneking, F.

    2006-03-01

    Peripheral nerve blocks present an alternative to general anesthesia in certain surgical procedures and a means of acute pain relief through continuous blockades. They have been shown to decrease the incidence of postoperative nausea and vomiting, reduce oral narcotic side effects, and improve sleep quality. Injecting needles, which carry small stimulating currents, are often used to aid in locating the target nerve bundle. With this technique, muscle responses indicate needle proximity to the corresponding nerve bundle. Failure rates in first injection attempts prompted our study of electric field distributions. Finite difference methods were used to solve for the electric fields generated by two widely used needles. Geometric differences in the needles effect variations in their electric field and current distributions. Further investigations may suggest needle modifications that result in a reduction of initial probing failures.

  13. [Brief introduction of acupuncture needling and teaching keypoint].

    PubMed

    Hou, Shu-wei; Guo, Li; Kong, Su-ping

    2014-09-01

    We summarized our accumulated clinical and teaching experiences and explored the regularity of acupuncture needling and teaching. It is of great importance in pressing hand during inserting needle. Stroking and pressing are two crucial parts which deserve more attention, and seldom useage of pressing hand should be abolished. Operating hand needs practice before inserting needle, while it should fully relaxed during inserting. Blending "touching", "stretch" "gathering" "erupting" and "advancing" in single moment, applying appropriate dynamic mode of inserting needle such as "join 3 forces as one" "3 points in a line" expertly and naturally. In addition, enough attention should be paid on "altering direction" and "shifting point". Inserting deftly and powerfully, no/slight sensation, deqi when inserting needle are the highest reflection as an acupuncturist.

  14. Design of an Optically Controlled MR-Compatible Active Needle

    PubMed Central

    Ryu, Seok Chang; Quek, Zhan Fan; Koh, Je-Sung; Renaud, Pierre; Black, Richard J.; Moslehi, Behzad; Daniel, Bruce L.; Cho, Kyu-Jin; Cutkosky, Mark R.

    2015-01-01

    An active needle is proposed for the development of magnetic resonance imaging (MRI)-guided percutaneous procedures. The needle uses a low-transition-temperature shape memory alloy (LT SMA) wire actuator to produce bending in the distal section of the needle. Actuation is achieved with internal optical heating using laser light transported via optical fibers and side coupled to the LT SMA. A prototype, with a size equivalent to a standard 16-gauge biopsy needle, exhibits significant bending, with a tip deflection of more than 14° in air and 5° in hard tissue. A single-ended optical sensor with a gold-coated tip is developed to measure the curvature independently of temperature. The experimental results in tissue phantoms show that human tissue causes fast heat dissipation from the wire actuator; however, the active needle can compensate for typical targeting errors during prostate biopsy. PMID:26512231

  15. Cellular prion protein transduces neuroprotective signals

    PubMed Central

    Chiarini, Luciana B.; Freitas, Adriana R.O.; Zanata, Silvio M.; Brentani, Ricardo R.; Martins, Vilma R.; Linden, Rafael

    2002-01-01

    To test for a role for the cellular prion protein (PrPc) in cell death, we used a PrPc-binding peptide. Retinal explants from neonatal rats or mice were kept in vitro for 24 h, and anisomycin (ANI) was used to induce apoptosis. The peptide activated both cAMP/protein kinase A (PKA) and Erk pathways, and partially prevented cell death induced by ANI in explants from wild-type rodents, but not from PrPc-null mice. Neuroprotection was abolished by treatment with phosphatidylinositol-specific phospholipase C, with human peptide 106–126, with certain antibodies to PrPc or with a PKA inhibitor, but not with a MEK/Erk inhibitor. In contrast, antibodies to PrPc that increased cAMP also induced neuroprotection. Thus, engagement of PrPc transduces neuroprotective signals through a cAMP/PKA-dependent pathway. PrPc may function as a trophic receptor, the activation of which leads to a neuroprotective state. PMID:12093733

  16. FEM implementation of a magnetostrictive transducer

    NASA Astrophysics Data System (ADS)

    Benatar, J. G.; Flatau, A. B.

    2005-05-01

    Magnetostrictive transducers are used in a broad variety of applications that include linear pump drives mechanisms, active noise and vibration control systems and sonar systems. Optimization of their performance relies on accurate modeling of the static and dynamic behavior of the magnetostrictive material. The nonlinearity of some magnetostrictive material properties along with eddy current power losses occurring in both the magnetostrictive material and in the magnetic circuit of the system makes this task particularly difficult. This paper introduces a static and a dynamic three-dimensional multi-physics boundary value problem that includes magneto-mechanical coupling for modeling magnetostriction and electromagnetic coupling for modeling eddy-current power loss (dynamic case only). It also includes the effect of the magnetic stress tensor, also known as Maxwell stress tensor, introduced by Kannan. The dynamic formulation is inspired by the finite element formulation in the Galerkin form introduced by Perez-Aparicio and Sosa, but focuses on a weak form formulation of the problem suitable for implementation in the finite element commercial software FEMLAB 3.1. Finally, an example is presented and compared to experimental results to validate the static model.

  17. Piezoelectric transducer design for a miniaturized injectable acoustic transmitter

    SciTech Connect

    Li, Huidong; Jung, Ki Won; Deng, Zhiqun D.

    2015-10-07

    Acoustic telemetry has been an important tool in the last 20 years for studying fish survival and migration behaviors during and after dam passage. This technology uses implantable acoustic transmitters as tags to three-dimensionally track the movement of fish. However, the relatively large weights and sizes of commercially available transmitters limit the populations of fish that could be studied. The surgical implantation procedures required may also injure fish and also incur a significant amount of labor. Therefore, a smaller, lighter, and injectable tag was needed, and similar or better acoustic performance and service life over that provided by existing commercial tags was desired. To develop such a small transmitter, a number of technical challenges, including design optimization of the piezoelectric transducer, needed to be overcome. The goal of our efforts to optimize the transducer focused on improving the average source level in the 180° range in which the transmitter was facing the receiving hydrophone, so as to increase the transmitter’s detection probability. This paper reports the techniques that were explored and developed to achieve this goal. We found that a novel off-center tube transducer improved the average source level of the front half of the transducer by 1.5 dB. An acoustic reflector attached to the back of the transducer also improved the source level by 3 dB when the transducer was pointed toward the receiving hydrophone, although the source level on the sides of the transducer was reduced. We found that too small a gap between the transducer and the component placed behind it resulted in distortion of the beam pattern. To overcome that issue, we connected a tuning inductor in series with the transducer to help optimize the source level. Furthermore, the findings and techniques developed in this work contributed to the successful development and implementation of a new injectable transmitter.

  18. Bonding and impedance matching of acoustic transducers using silver epoxy.

    PubMed

    Son, Kyu Tak; Lee, Chin C

    2012-04-01

    Silver epoxy was selected to bond transducer plates on glass substrates. The properties and thickness of the bonding medium affect the electrical input impedance of the transducer. Thus, the thickness of the silver epoxy bonding layer was used as a design parameter to optimize the structure for the transducer input impedance to match the 50 Ω output impedance of most radio frequency (RF) generators. Simulation and experimental results show that nearly perfect matching is achieved without using any matching circuit. At the matching condition, the transducer operates at a frequency band a little bit below the half-wavelength resonant frequency of the piezoelectric plate. In experiments, lead titanate (PT) piezoelectric plates were employed. Both full-size, 11.5 mm × 2 mm × 0.4 mm, and half-size, 5.75 mm × 2 mm × 0.4 mm, can be well matched using optimal silver epoxy thickness. The transducer assemblies demonstrate high efficiency. The conversion loss from electrical power to acoustic power in soda-lime glass is 4.3 dB. This loss is low considering the fact that the transducers operate at off-resonance by 12%. With proper choice of silver epoxy thickness, the transducer can be matched at the fundamental, the 3rd and 5th harmonic frequencies. This leads to the possible realization of triple-band transducers. Reliability was assessed with thermal cycling test according to Telcordia GR-468-Core recommendation. Of the 30 transducer assemblies tested, none broke until 2900 cycles and 27 have sustained beyond 4050 cycles.

  19. Piezoelectric transducer design for a miniaturized injectable acoustic transmitter

    DOE PAGES

    Li, Huidong; Jung, Ki Won; Deng, Zhiqun D.

    2015-10-07

    Acoustic telemetry has been an important tool in the last 20 years for studying fish survival and migration behaviors during and after dam passage. This technology uses implantable acoustic transmitters as tags to three-dimensionally track the movement of fish. However, the relatively large weights and sizes of commercially available transmitters limit the populations of fish that could be studied. The surgical implantation procedures required may also injure fish and also incur a significant amount of labor. Therefore, a smaller, lighter, and injectable tag was needed, and similar or better acoustic performance and service life over that provided by existing commercialmore » tags was desired. To develop such a small transmitter, a number of technical challenges, including design optimization of the piezoelectric transducer, needed to be overcome. The goal of our efforts to optimize the transducer focused on improving the average source level in the 180° range in which the transmitter was facing the receiving hydrophone, so as to increase the transmitter’s detection probability. This paper reports the techniques that were explored and developed to achieve this goal. We found that a novel off-center tube transducer improved the average source level of the front half of the transducer by 1.5 dB. An acoustic reflector attached to the back of the transducer also improved the source level by 3 dB when the transducer was pointed toward the receiving hydrophone, although the source level on the sides of the transducer was reduced. We found that too small a gap between the transducer and the component placed behind it resulted in distortion of the beam pattern. To overcome that issue, we connected a tuning inductor in series with the transducer to help optimize the source level. Furthermore, the findings and techniques developed in this work contributed to the successful development and implementation of a new injectable transmitter.« less

  20. Design, analysis, and modeling of giant magnetostrictive transducers

    NASA Astrophysics Data System (ADS)

    Calkins, Frederick Theodore

    The increased use of giant magnetostrictive, Terfenol-D transducers in a wide variety of applications has led to a need for greater understanding of the materials performance. This dissertation attempts to add to the Terfenol-D transducer body of knowledge by providing an in-depth analysis and modeling of an experimental transducer. A description of the magnetostriction process related to Terfenol-D includes a discussion of material properties, production methods, and the effect of mechanical stress, magnetization, and temperature on the material performance. The understanding of the Terfenol-D material performance provides the basis for an analysis of the performance of a Terfenol-D transducer. Issues related to the design and utilization of the Terfenol-D material in the transducers are considered, including the magnetic circuit, application of mechanical prestress, and tuning of the mechanical resonance. Experimental results from two broadband, Tonpilz design transducers show the effects of operating conditions (prestress, magnetic bias, AC magnetization amplitude, and frequency) on performance. In an effort to understand and utlilize the rich performance space described by the experimental results a variety of models are considered. An overview of models applicable to Terfenol-D and Terfenol-D transducers is provided, including a discussion of modeling criteria. The Jiles-Atherton model of ferromagnetic hysteresis is employed to describe the quasi-static transducer performance. This model requires the estimation of only six physically-based parameters to accurately simulate performance. The model is shown to be robust with respect to model parameters over a range of mechanical prestress, magnetic biases, and AC magnetic field amplitudes, allowing predictive capability within these ranges. An additional model, based on electroacoustics theory, explains trends in the frequency domain and facilitates an analysis of efficiency based on impedance and admittance

  1. 21 CFR 870.2900 - Patient transducer and electrode cable (including connector).

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... transducer and electrode cable (including connector) is an electrical conductor used to transmit signals from, or power or excitation signals to, patient-connected electrodes or transducers. (b)...

  2. Optical Flow-Based Tracking of Needles and Needle-Tip Localization Using Circular Hough Transform in Ultrasound Images

    PubMed Central

    Ayvali, Elif; Desai, Jaydev P.

    2014-01-01

    Image-guided interventions have become the standard of care for needle-based procedures. The success of the image-guided procedures depends on the ability to precisely locate and track the needle. This work is primarily focused on 2D ultrasound-based tracking of a hollow needle (cannula) that is composed of straight segments connected by shape memory alloy actuators. An in-plane tracking algorithm based on optical flow was proposed to track the cannula configuration in real-time. Optical flow is a robust tracking algorithm that can easily run on a CPU. However, the algorithm does not perform well when it is applied to the ultrasound images directly due to the intensity variation in the images. The method presented in this work enables using the optical flow algorithm on ultrasound images to track features of the needle. By taking advantage of the bevel tip, Circular Hough transform was used to accurately locate the needle tip when the imaging is out-of-plane. Through experiments inside tissue phantom and ex-vivo experiments in bovine kidney, the success of the proposed tracking methods were demonstrated. Using the methods presented in this work, quantitative information about the needle configuration is obtained in real-time which is crucial for generating control inputs for the needle and automating the needle insertion. PMID:25503523

  3. Slip-ring-based multi-transducer photoacoustic tomography system.

    PubMed

    Deng, Zijian; Li, Wenzhao; Li, Changhui

    2016-06-15

    Although the transducer array-based photoacoustic tomography (PAT) system provides fast imaging speed, its high cost and system complexity hinder its implementations. In this Letter, for the first time, to the best of our knowledge, the electrical slip ring was used to develop a PAT system that compromises the cost and the imaging speed. This system enables using multiple transducers to image the target simultaneously and continuously. In addition, it is versatile to use different transducers. The performance of this PAT system has been demonstrated by both phantom and in vivo animal experiments.

  4. USE OF PELTIER COOLERS AS SOIL HEAT FLUX TRANSDUCERS.

    USGS Publications Warehouse

    Weaver, H.L.; Campbell, G.S.

    1985-01-01

    Peltier coolers were modified and calibrated to serve as soil heat flux transducers. The modification was to fill their interiors with epoxy. The average calibration constant on 21 units was 13. 6 plus or minus 0. 8 kW m** minus **2 V** minus **1 at 20 degree C. This sensitivity is about eight times that of the two thermopile transducers with which comparisons were made. The thermal conductivity of the Peltier cooler transducers was 0. 4 W m** minus **1 degree C** minus **1, which is comparable to that of dry soil.

  5. Use of submersible pressure transducers in water-resources investigations

    USGS Publications Warehouse

    Freeman, Lawrence A.; Carpenter, Michael C.; Rosenberry, Donald O.; Rousseau, Joseph P.; Unger, Randy; McLean, John S.

    2004-01-01

    Submersible pressure transducers, developed in the early 1960s, have made the collection of water-level and pressure data much more convenient than former methods. Submersible pressure transducers, when combined with electronic data recorders have made it possible to collect continuous or nearly continuous water-level or pressure data from wells, piezometers, soil-moisture tensiometers, and surface water gages. These more frequent measurements have led to an improved understanding of the hydraulic processes in streams, soils, and aquifers. This manual describes the operational theory behind submersible pressure transducers and provides information about their use in hydrologic investigations conducted by the U.S. Geological Survey.

  6. Broadband electrical impedance matching for piezoelectric ultrasound transducers.

    PubMed

    Huang, Haiying; Paramo, Daniel

    2011-12-01

    This paper presents a systematic method for designing broadband electrical impedance matching networks for piezoelectric ultrasound transducers. The design process involves three steps: 1) determine the equivalent circuit of the unmatched piezoelectric transducer based on its measured admittance; 2) design a set of impedance matching networks using a computerized Smith chart; and 3) establish the simulation model of the matched transducer to evaluate the gain and bandwidth of the impedance matching networks. The effectiveness of the presented approach is demonstrated through the design, implementation, and characterization of impedance matching networks for a broadband acoustic emission sensor. The impedance matching network improved the power of the acquired signal by 9 times.

  7. Structural integrity of composites with embedded piezoelectric ceramic transducers

    NASA Astrophysics Data System (ADS)

    Paget, Christophe A.; Levin, Klas

    1999-06-01

    The objective of this paper is to determine the strength reduction due to the embedment of a piezoelectric ceramic transducer in a composite. The composite was made from carbon/epoxy prepreg with a cross-ply lay-up. The transducer was embedded in the mid-plane of the composite material. The specimens were tested in tensile and compressive static loading. It was found that the embedded piezoelectric ceramic element with its interconnectors did not reduce the strength of the composite. In tensile and compressive static tests, the final failure did not coincide with the embedded piezoelectric ceramic transducer location in the composite.

  8. Analysis of Frequency Response Characteristics of Polymer Ultrasonic Transducers

    NASA Astrophysics Data System (ADS)

    Ohigashi, Hiroji; Itoh, Toru; Kimura, Kuniko; Nakanishi, Toshiharu; Suzuki, Miyo

    1988-03-01

    Piezoelectric polymers have large dielectric and mechanical internal losses. In this study, we introduced internal losses into Mason’s equivalent circuit, and analyzed the effects of these losses on the transducer response, mainly in the frequency domain. To prove the validity of the theoretical analysis, we fabricated polymer transducers of several backing load types which are effective for practical use, using vinylidene fluoride and trifluoroethylene copolymer films, and evaluated their frequency and impulse responses. The experimental results are in good agreement with the theoretical prediction. We conclude that a consideration of the internal losses is essential for the proper design and correct evaluation of polymer transducers.

  9. Optimization of ultrasonic transducers for selective guided wave actuation

    NASA Astrophysics Data System (ADS)

    Miszczynski, Mateusz; Packo, Pawel; Zbyrad, Paulina; Stepinski, Tadeusz; Uhl, Tadeusz; Lis, Jerzy; Wiatr, Kazimierz

    2016-04-01

    The application of guided waves using surface-bonded piezoceramic transducers for nondestructive testing (NDT) and Structural Health Monitoring (SHM) have shown great potential. However, due to difficulty in identification of individual wave modes resulting from their dispersive and multi-modal nature, selective mode excitement methods are highly desired. The presented work focuses on an optimization-based approach to design of a piezoelectric transducer for selective guided waves generation. The concept of the presented framework involves a Finite Element Method (FEM) model in the optimization process. The material of the transducer is optimized in topological sense with the aim of tuning piezoelectric properties for actuation of specific guided wave modes.

  10. Linear-array ultrasonic waveguide transducer for under sodium viewing.

    SciTech Connect

    Sheen, S. H.; Chien, H. T.; Wang, K.; Lawrence, W. P.; Engel, D.; Nuclear Engineering Division

    2010-09-01

    In this report, we first present the basic design of a low-noise waveguide and its performance followed by a review of the array transducer technology. The report then presents the concept and basic designs of arrayed waveguide transducers that can apply to under-sodium viewing for in-service inspection of fast reactors. Depending on applications, the basic waveguide arrays consist of designs for sideway and downward viewing. For each viewing application, two array geometries, linear and circular, are included in design analysis. Methods to scan a 2-D target using a linear array waveguide transducer are discussed. Future plan to develop a laboratory array waveguide prototype is also presented.

  11. [Acupuncture therapy for regaining consciousness in terms of acupoint location, needle insertion and needle manipulation].

    PubMed

    Meng, Xianggang; Gu, Wenlong; Ma, Fen; Du, Yuzheng; Zhao, Qi

    2015-03-01

    Acupuncture therapy for regaining consciousness activates soreness, numbness, distention, heaviness, radiating and moving, electric shock and ant climbing sensations at the specific acupoints in the stroke patients. Radiating and moving sensations are the summary of needling sensations such as soreness, numbness and twitching presenting during lifting and thrusting manipulation. These sensations are the essential factors of the therapeutic effect of regaining consciousness. Radiating sensation refers to the conduction along meridians and radiation of soreness and numbness. Moving sensation refers to the local muscular twitching at acupoints and the involuntary movement of limbs, joints and the distal. Acupuncture at the specific acupoints achieves radiating and moving sensations for promoting the circulation in meridians, regulating qi and mind and balancing yin and yang in stroke patients. This therapy was introduced in the paper in view of acupoint location, needle insertion and manipulation.

  12. Reducing the Effect of Transducer Mount Induced Noise on Aeroacoustic Wind Tunnel Testing Data with a New Transducer Mount Design

    NASA Technical Reports Server (NTRS)

    Herron, Andrew J.; Reed, Darren K.; Nance, Donald K.

    2015-01-01

    Flight vehicle aeroacoustic environments induced during transonic and supersonic flight are usually predicted by subscale wind tunnel testing utilizing high frequency miniature pressure transducers. In order to minimize noise induced by the measurement itself, transducer flush mounting with the model surface is very important. The National Aeronautics and Space Administration (NASA) has accomplished flushness in recent testing campaigns via use of a transducer holder that can be machined and sanded. A single hole in the holder allows the flow medium to interact with the transducer diaphragm. Noise is induced by the resulting cavity however, and is a challenge to remove in post-processing. A new holder design has been developed that minimizes the effects of this transducer mount induced noise (XMIN) by reducing the resonance amplitude or increasing its resonance frequency beyond the range of interest. This paper describes a test conducted at the NASA/George C. Marshall Space Flight Center Trisonic Wind Tunnel intended to verify the effectiveness of this design. The results from this test show that this new transducer holder design does significantly reduce the influence of XMIN on measured fluctuating pressure levels without degrading a transducer's ability to accurately measure the noise external to the model.

  13. Fine needle aspiration cytology in fibromatosis

    PubMed Central

    Tanwar, Pranay; Gupta, Nalini; Vasishta, Rakesh Kumar; Singh, Gurpreet

    2012-01-01

    Fibromatosis form a spectrum of clinicopathologic entities characterized by the infiltrative proliferation of fibroblasts that lack malignant cytologic features. The fibromatosis can be localized or infiltrative and multicentric and can involve internal tissues and organs as the mesentery, retroperitoneum, breast, and almost every organ and region of the body, including the bones, the meninges and the central nervous system. We report a case of 37-year-old male who presented with a right supraclavicular mass with superficial infiltrative type of fibromatosis and fine needle aspiration cytology (FNAC) was performed. We report this case because of limited literature of FNAC in fibromatosis and quick role of FNAC in the diagnosis of fibromatosis. PMID:22438623

  14. Multiple needle puncturing: balancing the varus knee.

    PubMed

    Bellemans, Johan

    2011-09-09

    The so-called "pie crusting" technique using multiple stab incisions is a well-established procedure for correcting tightness of the iliotibial band in the valgus knee. It is, however, not applicable for balancing the medial side in varus knees because of the risk for iatrogenic transsection of the medial collateral ligament (MCL). This article presents our experience with a safer alternative and minimally invasive technique for medial soft tissue balancing, where we make multiple punctures in the MCL using a 19-gauge needle to progressively stretch the MCL until a correct ligament balance is achieved. Our technique requires minimal to no additional soft tissue dissection and can even be performed percutaneously when necessary. This technique, therefore, does not impact the length of the skin or soft tissue incisions. We analyzed 61 cases with varus deformity that were intraoperatively treated using this technique. In 4 other cases, the technique was used as a percutaneous procedure to correct postoperative medial tightness that caused persistent pain on the medial side. The procedure was considered successful when a 2- to 4-mm mediolateral joint line opening was obtained in extension and 2 to 6 mm in flexion. In 62 cases (95%), a progressive correction of medial tightness was achieved according to the above-described criteria. Three cases were overreleased and required compensatory release of the lateral structures and use of a thicker insert. Based on these results, we consider needle puncturing an effective and safe technique for progressive correction of MCL tightness during minimally invasive total knee arthroplasty.

  15. Needle-based confocal laser endomicroscopy

    PubMed Central

    Giovannini, Marc

    2015-01-01

    New applications of confocal laser endomicroscopy were developed as pCLE in the bile duct and nCLE for pancreatic cystic tumors, pancreatic masses and lymph nodes. The aim of this paper would be to give you an update in this new technology and to try to define its place in the diagnosis of cystic and solid pancreatic masses. The material used was a 19G EUS-needle in which the stylet was replaced by the Confocal mini-probe. The mini-probe (0.632 mm of diameter) is pre-loaded and screwed by a locking device in the EUS-Needle and guided endosonographically in the target. Regarding pancreatic cystic lesion, the presence of epithelial villous structures based on nCLE was associated with pancreatic cystic neoplasm (IPMN) (P = 0.004) and provided a sensitivity of 59%, specificity of 100%, positive predictive value of 100%, and negative predictive value of 50%. A superficial vascular network pattern visualized on nCLE was identified in serous cystadenomas. It corresponded on pathological specimen to a dense and subepithelial capillary vascularization. The accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of this sign for the diagnosis of SCA were 87%, 69%, 100%, 100%, and 82%, respectively. In pancreatic adenocarcinomas, nCLE found vascular leakage with irregular vessels with leakage of fluorescein into the tumor, large dark clumps which correspond to humps of malignant cells. These criteria correlate with the histological structure of those tumors which are characterized by tumoral glands, surrounded by fibrosis in case of fibrous stroma tumor. Neuroendocrine tumors showed a dense network of small vessels on a dark background, which fits with the histological structure based on cord of cells surrounded by vessels and by fibrosis. nCLE is feasible during a EUS examination; these preliminary results are very encouraging and may be used in the future in case of inconclusive EUS-FNA. PMID:26643694

  16. Remote Electromagnetic Vibration of Steerable Needles for Imaging in Power Doppler Ultrasound

    PubMed Central

    Cabreros, Sarah S.; Jimenez, Nina M.; Greer, Joseph D.; Adebar, Troy K.; Okamura, Allison M.

    2015-01-01

    Robotic needle steering systems for minimally invasive medical procedures require complementary medical imaging systems to track the needles in real time. Ultrasound is a promising imaging modality because it offers relatively low-cost, real-time imaging of the needle. Previous methods applied vibration to the base of the needle using a voice coil actuator, in order to make the needle visible in power Doppler ultrasound. We propose a new method for needle tip vibration, using electromagnetic actuation of small permanent magnets placed inside the needle to improve needle tip visibility in power Doppler imaging. Robotic needle insertion experiments using artificial tissue and ex vivo porcine liver showed that the electromagnetic tip vibration method can generate a stronger Doppler response compared to the previous base vibration method, resulting in better imaging at greater needle depth in tissue. It also eliminates previous issues with vibration damping along the shaft of the needle. PMID:26413379

  17. Remote Electromagnetic Vibration of Steerable Needles for Imaging in Power Doppler Ultrasound.

    PubMed

    Cabreros, Sarah S; Jimenez, Nina M; Greer, Joseph D; Adebar, Troy K; Okamura, Allison M

    2015-05-01

    Robotic needle steering systems for minimally invasive medical procedures require complementary medical imaging systems to track the needles in real time. Ultrasound is a promising imaging modality because it offers relatively low-cost, real-time imaging of the needle. Previous methods applied vibration to the base of the needle using a voice coil actuator, in order to make the needle visible in power Doppler ultrasound. We propose a new method for needle tip vibration, using electromagnetic actuation of small permanent magnets placed inside the needle to improve needle tip visibility in power Doppler imaging. Robotic needle insertion experiments using artificial tissue and ex vivo porcine liver showed that the electromagnetic tip vibration method can generate a stronger Doppler response compared to the previous base vibration method, resulting in better imaging at greater needle depth in tissue. It also eliminates previous issues with vibration damping along the shaft of the needle.

  18. Electromechanically active polymer transducers: research in Europe

    NASA Astrophysics Data System (ADS)

    Carpi, Federico; Graz, Ingrid; Jager, Edwin; Ladegaard Skov, Anne; Vidal, Frédéric

    2013-10-01

    Smart materials and structures based on electromechanically active polymers (EAPs) represent a fast growing and stimulating field of research and development. EAPs are materials capable of changing dimensions and/or shape in response to suitable electrical stimuli. They are commonly classified in two major families: ionic EAPs (activated by an electrically induced transport of ions and/or solvent) and electronic EAPs (activated by electrostatic forces). These polymers show interesting properties, such as sizable active strains and/or stresses in response to electrical driving, high mechanical flexibility, low density, structural simplicity, ease of processing and scalability, no acoustic noise and, in most cases, low costs. Since many of these characteristics can also describe natural muscle tissues from an engineering standpoint, it is not surprising that EAP transducers are sometimes also referred to as 'muscle-like smart materials' or 'artificial muscles'. They are used not only to generate motion, but also to sense or harvest energy from it. In particular, EAP electromechanical transducers are studied for applications that can benefit from their 'biomimetic' characteristics, with possible usages from the micro- to the macro-scale, spanning several disciplines, such as mechatronics, robotics, automation, biotechnology and biomedical engineering, haptics, fluidics, optics and acoustics. Currently, the EAP field is just undergoing its initial transition from academic research into commercialization, with companies starting to invest in this technology and the first products appearing on the market. This focus issue is intentionally aimed at gathering contributions from the most influential European groups working in the EAP field. In fact, today Europe hosts the broadest EAP community worldwide. The rapid expansion of the EAP field in Europe, where it historically has strong roots, has stimulated the creation of the 'European Scientific Network for Artificial

  19. Manipulation of acoustic focusing with an active and configurable planar metasurface transducer

    PubMed Central

    Zhao, Jiajun; Ye, Huapeng; Huang, Kun; Chen, Zhi Ning; Li, Baowen; Qiu, Cheng-Wei

    2014-01-01

    It has a pivotal role in medical science and in industry to concentrate the acoustic energy created with piezoelectric transducers (PTs) into a specific area. However, previous researches seldom consider the focal resolution, whose focal size is much larger than one wavelength. Furthermore, there is to date no such design method of PTs that allows a large degree of freedom to achieve designed focal patterns. Here, an active and configurable planar metasurface PT prototype is proposed to manipulate the acoustic focal pattern and the focal resolution freely. By suitably optimized ring configurations of the active metasurface PT, we demonstrate the manipulation of focal patterns in acoustic far fields, such as the designed focal needle and multi foci. Our method is also able to manipulate and improve the cross-sectional focal resolution from subwavelength to the extreme case: the deep sub-diffraction-limit resolution. Via the acoustic Rayleigh-Sommerfeld diffraction integral (RSI) cum the binary particle swarm optimization (BPSO), the free manipulation of focusing properties is achieved in acoustics for the first time. Our approach may offer more initiatives where the strict control of acoustic high-energy areas is demanding. PMID:25174409

  20. Manipulation of acoustic focusing with an active and configurable planar metasurface transducer

    NASA Astrophysics Data System (ADS)

    Zhao, Jiajun; Ye, Huapeng; Huang, Kun; Chen, Zhi Ning; Li, Baowen; Qiu, Cheng-Wei

    2014-09-01

    It has a pivotal role in medical science and in industry to concentrate the acoustic energy created with piezoelectric transducers (PTs) into a specific area. However, previous researches seldom consider the focal resolution, whose focal size is much larger than one wavelength. Furthermore, there is to date no such design method of PTs that allows a large degree of freedom to achieve designed focal patterns. Here, an active and configurable planar metasurface PT prototype is proposed to manipulate the acoustic focal pattern and the focal resolution freely. By suitably optimized ring configurations of the active metasurface PT, we demonstrate the manipulation of focal patterns in acoustic far fields, such as the designed focal needle and multi foci. Our method is also able to manipulate and improve the cross-sectional focal resolution from subwavelength to the extreme case: the deep sub-diffraction-limit resolution. Via the acoustic Rayleigh-Sommerfeld diffraction integral (RSI) cum the binary particle swarm optimization (BPSO), the free manipulation of focusing properties is achieved in acoustics for the first time. Our approach may offer more initiatives where the strict control of acoustic high-energy areas is demanding.