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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.

    Science.gov (United States)

    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. A 45-MHz continuum survey of the northern hemisphere

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Huang, C.-C. [Department of Electronic Engineering, Fu Jen Catholic University, Taipei 24205, Taiwan (China); Chen Ruimin; Zhou Qifa; Shung, K Kirk [NIH Resource on Medical Ultrasonic Transducer Technology, Department of Biomedical Engineering, University of Southern California, Los Angeles, CA 90089 (United States); Tsui, P.-H. [Division of Mechanics, Research Center for Applied Sciences, Academia Sinica, Taipei 11529, Taiwan (China); Humayun, Mark S [Doheny Retina Institute, Doheny Eye Institute, Department of Ophthalmology, Keck School of Medicine, University of Southern California, Los Angeles, CA 90033 (United States)], E-mail: j648816n@ms23.hinet.net

    2009-10-07

    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{sup -1} MHz{sup -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.

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

    Science.gov (United States)

    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%.

  6. Implementation of a Rotational Ultrasound Biomicroscopy System Equipped with a High-Frequency Angled Needle Transducer — Ex Vivo Ultrasound Imaging of Porcine Ocular Posterior Tissues

    Directory of Open Access Journals (Sweden)

    Tae-Hoon Bok

    2014-09-01

    Full Text Available The mechanical scanning of a single element transducer has been mostly utilized for high-frequency ultrasound imaging. However, it requires space for the mechanical motion of the transducer. In this paper, a rotational scanning ultrasound biomicroscopy (UBM system equipped with a high-frequency angled needle transducer is designed and implemented in order to minimize the space required. It was applied to ex vivo ultrasound imaging of porcine posterior ocular tissues through a minimal incision hole of 1 mm in diameter. The retina and sclera for the one eye were visualized in the relative rotating angle range of 270° ~ 330° and at a distance range of 6 ~ 7 mm, whereas the tissues of the other eye were observed in relative angle range of 160° ~ 220° and at a distance range of 7.5 ~ 9 mm. The layer between retina and sclera seemed to be bent because the distance between the transducer tip and the layer was varied while the transducer was rotated. Certin features of the rotation system such as the optimal scanning angle, step angle and data length need to be improved for ensure higher accuracy and precision. Moreover, the focal length should be considered for the image quality. This implementation represents the first report of a rotational scanning UBM system.

  7. A partial 45 MHz sky temperature map obtained from the observations of five ST radars

    Directory of Open Access Journals (Sweden)

    B. Campistron

    Full Text Available A sky temperature map at 45 MHz covering declination between + 30° and + 60°  is presented. The sampling in right ascension is 20 min (~5° and 2°  in declination in most of the map. The originality of the work was to use cosmic emission measurements from five VHF Stratosphere-Troposphere (ST radars collected during long periods of routine meteorological surveys. This map, which has an accuracy in temperature of about 600 K, is intended first for radar reflectivity calibration and system performance monitoring. The presence of two strong radio sources, Cassiopeia A and Cygnus A, can also serve as the verification of the beam diagram, beam width, and beam pointing direction of the antenna. Finally, this work is an attempt to show the potentiality of ST radar for astronomical purposes.

    Key words. Meteorology and atmospheric dynamics (instruments and techniques – Radio science (radio astronomy

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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%.

  10. Driving electrostatic transducers

    DEFF Research Database (Denmark)

    Nielsen, Dennis; Knott, Arnold; Andersen, Michael A. E.

    2013-01-01

    Electrostatic transducers represent a very interesting alternative to the traditional inefficient electrodynamic transducers. In order to establish the full potential of these transducers, power amplifiers which fulfill the strict requirements imposed by such loads (high impedance, frequency depe...

  11. Steerable real-time sonographically guided needle biopsy.

    Science.gov (United States)

    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.

  12. Needle autopsy

    Directory of Open Access Journals (Sweden)

    Philip Davis Marsden

    1997-04-01

    Full Text Available Often in tropical practice there is not time or conditions to do a proper autopsy on a patient who has died. A needle biopsy technique is described for limited closed autopsy examination to clariffy organ histology. In this way the clinician may resolve puzzling fatal disease.Muitas vezes, em clínicas de países tropicais, não há tempo nem condições para se realizar uma necropsia adequada em um paciente que foi a óbito. Um técnica de biópsia por punção é descrita para fins de exame em necropsia limitadamente fechada, para esclarecimento da histologia do órgão. Dessa maneira, o clínico pode resolver enigmas de doenças fatais.

  13. Megahertz tonpilz transducer

    Science.gov (United States)

    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.

  14. Macro tree transducers

    NARCIS (Netherlands)

    Engelfriet, Joost; Vogler, Heiko

    1985-01-01

    Macro tree transducers are a combination of top-down tree transducers and macro grammars. They serve as a model for syntax-directed semantics in which context information can be handled. In this paper the formal model of macro tree transducers is studied by investigating typical automata theoretical

  15. Handbook of force transducers

    CERN Document Server

    Stefanescu, Dan Mihai

    2011-01-01

    Part I introduces the basic ""Principles and Methods of Force Measurement"" acording to a classification into a dozen of force transducers types: resistive, inductive, capacitive, piezoelectric, electromagnetic, electrodynamic, magnetoelastic, galvanomagnetic (Hall-effect), vibrating wires, (micro)resonators, acoustic and gyroscopic. Two special chapters refer to force balance techniques and to combined methods in force measurement. Part II discusses the ""(Strain Gauge) Force Transducers Components"", evolving from the classical force transducer to the digital / intelligent one, with the inco

  16. Gas speed flow transducer

    Directory of Open Access Journals (Sweden)

    Godovaniouk V. N.

    2011-08-01

    Full Text Available The design of a gas speed flow transducer using the coupling of gas speed and heat streams within the transducer itself is proposed. To maintain the heat balance between two thermoresistors under gas stream at different temperatures, it provides energy consumption monitoring. The detailed combined planar technology for the transducer production is presented. The worked-out measurement procedure allows to make measurements in the temperature range. Information enough to organize production of cheap, reliable and precise gas speed flow transducers is given.

  17. Modeling of ultrasound transducers

    DEFF Research Database (Denmark)

    Bæk, David

    This Ph.D. dissertation addresses ultrasound transducer modeling for medical ultrasound imaging and combines the modeling with the ultrasound simulation program Field II. The project firstly presents two new models for spatial impulse responses (SIR)s to a rectangular elevation focused transducer...

  18. Programming macro tree transducers

    DEFF Research Database (Denmark)

    Bahr, Patrick; Day, Laurence E.

    2013-01-01

    A tree transducer is a set of mutually recursive functions transforming an input tree into an output tree. Macro tree transducers extend this recursion scheme by allowing each function to be defined in terms of an arbitrary number of accumulation parameters. In this paper, we show how macro tree...... transducers can be concisely represented in Haskell, and demonstrate the benefits of utilising such an approach with a number of examples. In particular, tree transducers afford a modular programming style as they can be easily composed and manipulated. Our Haskell representation generalises the original...... definition of (macro) tree transducers, abolishing a restriction on finite state spaces. However, as we demonstrate, this generalisation does not affect compositionality....

  19. Triple-resonant transducers.

    Science.gov (United States)

    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.

  20. Improved transvenous liver biopsy needle

    DEFF Research Database (Denmark)

    Henriksen, Jens Henrik Sahl; Matzen, P; Christoffersen, P;

    1979-01-01

    A modified type of the standard transvenous cholangiography biopsy needle is described. The modified tranvenous liver biopsy needle caused only minimal artefactual changes of the liver biopsy specimens. The new type of biopsy needle is a modified Menghini needle. The conventional Menghini needle...... should be avoided for transvenous catheter biopsies because of risk of leaving catheter fragments in the liver....

  1. Compact Transducers and Arrays

    Science.gov (United States)

    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

  2. Pressure Transducer Locations

    Data.gov (United States)

    National Aeronautics and Space Administration — Files are located here, defining the locations of the pressure transducers on the HIRENASD model. These locations also correspond to the locations that analysts...

  3. Needle biopsy of histoplasmosis

    Energy Technology Data Exchange (ETDEWEB)

    Sinner, W.N.

    1980-12-01

    A case of histoplasmosis, simulating a bronchogenic carcinoma, was needle biopsied. Histoplasma capsulatum organisms were found in great numbers. Needle biopsy established an accurate diagnosis making an exploratory thoracotomy unnecessary and preventing the patient from an already planned lobectomy. Specific treatment with Amphotericin B healed the lesion.

  4. Precessing Ferromagnetic Needle Magnetometer.

    Science.gov (United States)

    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.

  5. Needle breakage: incidence and prevention.

    Science.gov (United States)

    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.

  6. Konstruktion af transducer

    DEFF Research Database (Denmark)

    Henriksen, Lars; Nielsen, Martin Pram

    Formålet med dette midtvejsprojekt er at udarbejde en transducer til måling af pressers stivhed. Dette er gjort på baggrund af en gennemgang af både presse- og stativ-typer samtidig med at udbøjningssituationen beskrives. Der introduceres en ide, der udgør grundkonceptet for opmålingsproceduren o...... færdige transducer – Load cellen. Strain gauge sørger for dataopsamlingen fra load cellen. Disse kalibreres således at transduceren er klar til de videre målinger der ligger i forlængelse af dette projekt....

  7. Glass-windowed ultrasound transducers.

    Science.gov (United States)

    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

  8. Modeling of phased array transducers.

    Science.gov (United States)

    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.

  9. Curved PVDF airborne transducer.

    Science.gov (United States)

    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.

  10. Future needs for biomedical transducers

    Science.gov (United States)

    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.

  11. Nano-optomechanical transducer

    Science.gov (United States)

    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.

  12. Three dimensional transducer

    Energy Technology Data Exchange (ETDEWEB)

    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.

  13. Frequency steerable acoustic transducers

    Science.gov (United States)

    Senesi, Matteo

    Structural health monitoring (SHM) is an active research area devoted to the assessment of the structural integrity of critical components of aerospace, civil and mechanical systems. Guided wave methods have been proposed for SHM of plate-like structures using permanently attached piezoelectric transducers, which generate and sense waves to evaluate the presence of damage. Effective interrogation of structural health is often facilitated by sensors and actuators with the ability to perform electronic, i.e. phased array, scanning. The objective of this research is to design an innovative directional piezoelectric transducer to be employed for the localization of broadband acoustic events, or for the generation of Lamb waves for active interrogation of structural health. The proposed Frequency Steerable Acoustic Transducers (FSATs) are characterized by a spatial arrangement of active material which leads to directional characteristics varying with frequency. Thus FSATs can be employed both for directional sensing and generation of guided waves without relying on phasing and control of a large number of channels. The analytical expression of the shape of the FSATs is obtained through a theoretical formulation for continuously distributed active material as part of a shaped piezoelectric device. The FSAT configurations analyzed in this work are a quadrilateral array and a geometry which corresponds to a spiral in the wavenumber domain. The quadrilateral array is experimentally validated, confirming the concept of frequency-dependent directionality. Its limited directivity is improved by the Wavenumber Spiral FSAT (WS-FSAT), which, instead, is characterized by a continuous frequency dependent directionality. Preliminary validations of the WS-FSAT, using a laser doppler vibrometer, are followed by the implementation of the WS-FSAT as a properly shaped piezo transducer. The prototype is first used for localization of acoustic broadband sources. Signal processing

  14. Stress wave focusing transducers

    Energy Technology Data Exchange (ETDEWEB)

    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.

  15. Numerical transducer modelling

    DEFF Research Database (Denmark)

    Cutanda, Vicente

    1999-01-01

    Numerical modelling is of importance for the design, improvement and study of acoustic transducers such as microphones and accelerometers. Techniques like the boundary element method and the finite element method are the most common supplement to the traditional empirical and analytical approaches...... errors and instabilities in the computations of numerical solutions. An investigation to deal with this narrow-gap problem has been carried out....

  16. Steerable Doppler transducer probes

    Energy Technology Data Exchange (ETDEWEB)

    Fidel, H.F.; Greenwood, D.L.

    1986-07-22

    An ultrasonic diagnostic probe is described which is capable of performing ultrasonic imaging and Doppler measurement consisting of: a hollow case having an acoustic window which passes ultrasonic energy and including chamber means for containing fluid located within the hollow case and adjacent to a portion of the acoustic window; imaging transducer means, located in the hollow case and outside the fluid chamber means, and oriented to direct ultrasonic energy through the acoustic window toward an area which is to be imaged; Doppler transducer means, located in the hollow case within the fluid chamber means, and movably oriented to direct Doppler signals through the acoustic window toward the imaged area; means located within the fluid chamber means and externally controlled for controllably moving the Doppler transducer means to select one of a plurality of axes in the imaged area along which the Doppler signals are to be directed; and means, located external to the fluid chamber means and responsive to the means for moving, for providing an indication signal for identifying the selected axis.

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

    Science.gov (United States)

    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.

  18. Myocardial wall-thickness transducer

    Science.gov (United States)

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

    1976-01-01

    Device consists of highly compliant circular beam attached to piezoresistive strain gage and barbed needle. Radial deflection of myocardium is measured with minimal disturbance of normal heart functions.

  19. Transducers for ultrasonic limb plethysmography

    Science.gov (United States)

    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.

  20. Piezoelectric transducer array microspeaker

    KAUST Repository

    Carreno, Armando Arpys Arevalo

    2016-12-19

    In this paper we present the fabrication and characterization of a piezoelectric micro-speaker. The speaker is an array of micro-machined piezoelectric membranes, fabricated on silicon wafer using advanced micro-machining techniques. Each array contains 2n piezoelectric transducer membranes, where “n” is the bit number. Every element of the array has a circular shape structure. The membrane is made out four layers: 300nm of platinum for the bottom electrode, 250nm or lead zirconate titanate (PZT), a top electrode of 300nm and a structural layer of 50

  1. Transducer of linear displacements

    Science.gov (United States)

    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. The Terry Biopsy Needle

    Science.gov (United States)

    Bond, Alan F.; Murphy, Fergus A.; Nanson, Eric M.

    1963-01-01

    Six illustrative cases are reported to demonstrate the versatility of the Terry biopsy needle as a useful instrument for obtaining satisfactory biopsy specimens from the liver and from other tissues as well. The apparatus and method of use are described and illustrated. ImagesFig. 1Fig. 2Fig. 3Fig. 4Fig. 5Fig. 6aFig. 6bFig. 7Fig. 8Fig. 9Fig. 10Fig. 11 PMID:13968726

  3. Numerical Transducer Modeling

    DEFF Research Database (Denmark)

    Henriquez, Vicente Cutanda

    This thesis describes the development of a numerical model of the propagation of sound waves in fluids with viscous and thermal losses, with application to the simulation of acoustic transducers, in particular condenser microphones for measurement. The theoretical basis is presented, numerical...... tools and implementation techniques are described and performance tests are carried out. The equations that govern the motion of fluids with losses and the corresponding boundary conditions are reduced to a form that is tractable for the Boundary Element Method (BEM) by adopting some hypotheses...... that are allowable in this case: linear variations, absence of flow, harmonic time variation, thermodynamical equilibrium and physical dimensions much larger than the molecular mean free path. A formulation of the BEM is also developed with an improvement designed to cope with the numerical difficulty associated...

  4. Optically transduced MEMS magnetometer

    Science.gov (United States)

    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.

  5. Calibration of Underwater Sound Transducers

    Directory of Open Access Journals (Sweden)

    H.R.S. Sastry

    1983-07-01

    Full Text Available The techniques of calibration of underwater sound transducers for farfield, near-field and closed environment conditions are reviewed in this paper .The design of acoustic calibration tank is mentioned. The facilities available at Naval Physical & Oceanographic Laboratory, Cochin for calibration of transducers are also listed.

  6. Circuit for Driving Piezoelectric Transducers

    Science.gov (United States)

    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

  7. A Direct Driver for Electrostatic Transducers

    DEFF Research Database (Denmark)

    Nielsen, Dennis; Knott, Arnold; Andersen, Michael A. E.

    2014-01-01

    Electrostatic transducers represent a very interesting alternative to the traditional inefficient electrodynamic transducers. In order to establish the full potential of these transducers, power amplifiers which fulfill the strict requirements imposed by such loads (high impedance, frequency depe...

  8. Passive wireless ultrasonic transducer systems

    Science.gov (United States)

    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.

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

    OpenAIRE

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

    2014-01-01

    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 ...

  10. Smart needles for percutaneous interventions

    NARCIS (Netherlands)

    Henken, K.R.

    2014-01-01

    The development of advanced needles for diagnostic and therapeutic purposes such as ablation and brachytherapy in the liver has offered minimally invasive therapies to patients that were previously untreatable. This thesis focuses on accurate placement of such needles guided by magnetic resonance im

  11. Frequency Steered Acoustic Transducer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research Phase I project is to develop, fabricate, and characterize a novel frequency steered acoustic transducer (FSAT) for the...

  12. Laboratories practice to transducers study

    Directory of Open Access Journals (Sweden)

    Kleber Romero Felizardo

    2004-01-01

    Full Text Available The objective of this work was to gather a collection of practical laboratory experiences , to discover the physical principles of different types of electrical transducers , and to compare them with theoretical models.

  13. Frequency Steered Acoustic Transducer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — This Small Business Innovation Research Phase II project is to fabricate, characterize, and verify performance of a new type of frequency steered acoustic transducer...

  14. Transducer Field Imaging Using Acoustography

    Directory of Open Access Journals (Sweden)

    Jaswinder S. Sandhu

    2012-01-01

    Full Text Available 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.

  15. Characterization of Dielectric Electroactive Polymer transducers

    DEFF Research Database (Denmark)

    Nielsen, Dennis; Møller, Martin B.; Sarban, Rahimullah;

    2014-01-01

    This paper analysis the small-signal model of the Dielectric Electro Active Polymer (DEAP) transducer. 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...

  16. Ultrasonic Transducer Irradiation Test Results

    Energy Technology Data Exchange (ETDEWEB)

    Daw, Joshua [Idaho National Lab. (INL), Idaho Falls, ID (United States); Palmer, Joe [Idaho National Lab. (INL), Idaho Falls, ID (United States); Ramuhalli, Pradeep [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Keller, Paul [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Montgomery, Robert [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Chien, Hual-Te [Argonne National Lab. (ANL), Argonne, IL (United States); Kohse, Gordon [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States); Tittmann, Bernhard [Pennsylvania State Univ., University Park, PA (United States); Reinhardt, Brian [Pennsylvania State Univ., University Park, PA (United States); Rempe, Joy [Rempe and Associates, Idaho Falls, ID (United States)

    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

  17. Changing the needle for lumbar punctures

    DEFF Research Database (Denmark)

    Engedal, Thorbjørn Søndergaard; Ording, H.; Vilholm, O. J.

    2015-01-01

    describes the process of changing the needle in an outpatient clinic of a Danish neurology department. Methods: Prospective interventional trial. Phase 1: 22 G cutting needle. Phase 2: 25 G non-cutting needle. Practical usability of each needle was recorded during the procedure, while the rate of PDPH...

  18. 21 CFR 880.5580 - Acupuncture needle.

    Science.gov (United States)

    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....

  19. Missing needle during episiotomy repair

    Directory of Open Access Journals (Sweden)

    Joydeb Roychowdhury

    2008-01-01

    Full Text Available Breakage and missing of the episiotomy needle is not uncommon occurrence at the hands of the junior doctors. Retrieving it from deeper tissue planes following its migration can be a challenging task.

  20. Ultrasound transducer assembly and method for manufacturing an ultrasound transducer assembly

    NARCIS (Netherlands)

    Dekker, R.; Henneken, V.A.; Louwerse, M.C.; Raganato, M.F.

    2015-01-01

    The present invention relates to an ultrasound transducer assembly (10), in particular for intravascular ultrasound systems. The ultrasound transducer assembly comprises at least one silicon substrate element (30) including an ultrasound transducer element (14) for emitting and receiving ultrasound

  1. Mechanical performance of disposable surgical needle holders.

    Science.gov (United States)

    Francis, E H; Towler, M A; Moody, F P; McGregor, W; Himel, H N; Rodeheaver, G T; Edlich, R F

    1992-01-01

    The mechanical performance of disposable Webster surgical needle holders supplied by three different surgical instrument companies was determined by recording the forces (clamping moment) applied by the different needle holder jaws to curved surgical needles. This investigation demonstrated that there was a large variability in the mechanical performance of the disposable needle holders supplied by each surgical instrument company. In addition, the mechanical performance of the disposable needle holder of each surgical instrument company was distinctly different.

  2. Calculations for Piezoelectric Ultrasonic Transducers

    DEFF Research Database (Denmark)

    Jensen, Henrik

    1986-01-01

    Analysis of piezoelectric ultrasonic transducers implies a solution of a boundary value problem, for a boay which consists of different materials, including a piezoelectric part. The problem is dynamic at frequencies, where a typical wavelength is somewhat less than the size of the body. Radiation...... and in particular the finite element method are considered. The finite element method is utilized for analysis of axisymmetric transducers. An explicit, fully piezoelectric, triangular ring element, with linear variations in displacememnt and electric potential is given. The influence of a fluid half-space is also...

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

    Energy Technology Data Exchange (ETDEWEB)

    Peng, J.; Lau, S.T.; Chao, C.; Dai, J.Y.; Chan, H.L.W. [The Hong Kong Polytechnic University, Department of Applied Physics and Materials Research Center, Hong Kong (China); Luo, H.S. [Chinese Academy of Sciences, The State Key Laboratory of High Performance Ceramics and Superfine Microstructure, Shanghai Institute of Ceramics, Shanghai (China); Zhu, B.P.; Zhou, Q.F.; Shung, K.K. [University of Southern California, Department of Biomedical Engineering and NIH Transducer Resource Center, Los Angeles, CA (United States)

    2010-01-15

    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{sub t}) and high piezoelectric constant (d{sub 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. (orig.)

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

    Science.gov (United States)

    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.

  5. Endoscopic ultrasound guided fine needle aspiration biopsy in the diagnosis of pancreatic masses.

    Science.gov (United States)

    Jinga, Mariana; Gheorghe, Cristian; Dumitrescu, Marius; Gheorghe, Liana; Nicolaie, Tudor

    2004-03-01

    Endoscopic ultrasound (EUS) represents a highly sensitive method for the detection of pancreatic masses. When available, EUS-guided fine needle aspiration (FNA) is the best technique for the diagnosis and staging of pancreatic cancer due to its ability to obtain tissue for diagnosis. The standardized indications for pancreatic EUS-FNA comprise the definite diagnosis of malignancy and histopathological confirmation of adenocarcinoma before surgical resection, chemo/radiotherapy, or celiac plexus neurolysis. The technique of performing EUS-FNA is described in detail, from the vizualization of the target lesion and adequate placement of the transducer to allow optimal needle access, to needle penetration and sampling of the targeted lesion. We report a series of 9 patients who underwent EUS-FNA and shortly review the indications, technique, results and impact of EUS-FNA on the management of these patients.

  6. Irradiation Testing of Ultrasonic Transducers

    Energy Technology Data Exchange (ETDEWEB)

    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.

  7. Transducers and Arrays for Underwater Sound

    CERN Document Server

    Sherman, Charles H

    2007-01-01

    This book is concerned with the theory, development and design of electroacoustic transducers for underwater applications, and is more comprehensive than any existing book in this field. It includes the basics of the six major types of electroacoustic transducers, with emphasis on the piezoelectric ceramic transducers that are currently most widely used. It presents the basic acoustics, as well as specific acoustic data, needed in transducer design and includes analysis of nonlinear effects in transducers. A large number of specific transducer designs, including both projectors and hydrophones, are described in detail as well as methods of modeling, evaluation and measurement. Analysis of transducer arrays, including the effects of mutual radiation impedance, as well as numerical models for transducers and arrays are also covered. The book contains an extensive Appendix of useful current information, including data on the latest transduction materials, and numerous diagrams that will facilitate its use by stu...

  8. Digital electrostatic acoustic transducer array

    KAUST Repository

    Carreno, Armando Arpys Arevalo

    2016-12-19

    In this paper we present the fabrication and characterization of an array of electrostatic acoustic transducers. The array is micromachined on a silicon wafer using standard micro-machining techniques. Each array contains 2n electrostatic transducer membranes, where “n” is the bit number. Every element of the array has a hexagonal membrane shape structure, which is separated from the substrate by 3µm air gap. The membrane is made out 5µm thick polyimide layer that has a bottom gold electrode on the substrate and a gold top electrode on top of the membrane (250nm). The wafer layout design was diced in nine chips with different array configurations, with variation of the membrane dimensions. The device was tested with 90 V giving and sound output level as high as 35dB, while actuating all the elements at the same time.

  9. Power Generation Using Piezoelectric Transducer

    Directory of Open Access Journals (Sweden)

    Tanu Chouhan

    2016-05-01

    Full Text Available The most basic need of today’s world is energy which is non-renewable source of energy available on earth. The need is increasing day by day, to overcome this there is requirement of energy harvesting. This paper attempts to show how man has been utilizing and optimizing kinetic energy. Current work also illustrates the working principle of piezoelectric crystal and various sources of vibration for the crystal. “The idea of energy harvesting is applicable to sensors as well as transducers that are placed and operated on some entities for a long time to replace the sensor module batteries. Such sensors are commonly called self-powered sensors.” Embarked piezoelectric transducer, which is an electromechanical converter, undergoes mechanical vibrations therefore produce electricity. This power source has many applications as in agriculture, home application and street lighting and as energy source for sensors in remote locations.

  10. Covert Channel Synthesis for Transducers

    OpenAIRE

    Benattar, Gilles; Bérard, Béatrice; Lime, Didier; Mullins, John; Roux, Olivier Henri; Sassolas, Mathieu

    2010-01-01

    Research report; Covert channels are a security threat for information systems, since they permit illegal flows, and sometimes leaks, of classified data. Although numerous descriptions have been given at a concrete level, relatively little work has been carried out at a more abstract level, outside probabilistic models. In this paper, we propose a definition of covert channels based on encoding and decoding binary messages with transducers, in a finite transition system. We first compare this...

  11. Dry needling — peripheral and central considerations

    OpenAIRE

    Dommerholt, Jan

    2011-01-01

    Dry needling is a common treatment technique in orthopedic manual physical therapy. Although various dry needling approaches exist, the more common and best supported approach targets myofascial trigger points. This article aims to place trigger point dry needling within the context of pain sciences. From a pain science perspective, trigger points are constant sources of peripheral nociceptive input leading to peripheral and central sensitization. Dry needling cannot only reverse some aspects...

  12. Needle-free influenza vaccination

    NARCIS (Netherlands)

    Amorij, Jean-Pierre; Hinrichs, Wouter L.J.; Frijlink, Henderik W.; Wilschut, Jan C.; Huckriede, Anke

    2010-01-01

    Vaccination is the cornerstone of influenza control in epidemic and pandemic situations. Influenza vaccines are typically given by intramuscular injection. However, needle-free vaccinations could offer several distinct advantages over intramuscular injections: they are pain-free, easier to distribut

  13. Transducers

    Digital Repository Service at National Institute of Oceanography (India)

    Chakraborty, B.

    stream_size 27 stream_content_type text/plain stream_name Encycl_Microcomputers_18_335.pdf.txt stream_source_info Encycl_Microcomputers_18_335.pdf.txt Content-Encoding ISO-8859-1 Content-Type text/plain; charset=ISO-8859-1 ...

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

    Energy Technology Data Exchange (ETDEWEB)

    Xia, Wenfeng, E-mail: wenfeng.xia@ucl.ac.uk; Desjardins, Adrien E. [Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London WC1E 6BT (United Kingdom); Mari, Jean Martial [Department of Medical Physics and Biomedical Engineering, University College London, Gower Street, London WC1E 6BT, United Kingdom and GePaSud, University of French Polynesia, Faa’a 98702, French Polynesia (France); West, Simeon J. [Department of Anaesthesia, University College Hospital, Main Theatres, Maple Bridge Link Corridor, Podium 3, 235 Euston Road, London NW1 2BU (United Kingdom); Ginsberg, Yuval; David, Anna L. [Institute for Women’s Health, University College London, 86-96 Chenies Mews, London WC1E 6HX (United Kingdom); Ourselin, Sebastien [Center for Medical Imaging Computing, University College London, Gower Street, London WC1E 6BT (United Kingdom)

    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

  15. Compensating for Torsion Windup in Steerable Needles

    Science.gov (United States)

    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

  16. Analog circuit for controlling acoustic transducer arrays

    Energy Technology Data Exchange (ETDEWEB)

    Drumheller, Douglas S. (Cedar Crest, NM)

    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.

  17. Mechanical and electrical characteristics of cymbal transducer

    Institute of Scientific and Technical Information of China (English)

    WANG Guangcan; ZHANG Jin; TIAN Wenjie; LIN Guoguang; LIAN Guandong; ZHANG Fuxue

    2005-01-01

    The electromechanical of Cymbal transducer has been researched. Under simple supporting condition, the mechanical and electrical characteristics have been analyzed by using Piezoelectric-elastic theory, Kirchhoff's thin shell vibration theory, Rayleigh-Ritz's theory and equivalent circuit method. The approximate solution and series resonance frequency equation have been given. Under no load, equivalent circuit, correlation parameters of cymbal transducer and the relations between the ratio of cavity depth to radius of Cymbal transducer with resonance frequency, electromechanical coupling coefficient of cymbal transducer have been researched. The best electromechanical coupling coefficient of cymbal transducer has been gained from the results of numerical analysis. It offers a valid theoretical foundation for optimum design of cymbal transducer.

  18. Transducers and arrays for underwater sound

    CERN Document Server

    Butler, John L

    2016-01-01

    This improved and updated second edition covers the theory, development, and design of electro-acoustic transducers for underwater applications. This highly regarded text discusses the basics of piezoelectric and magnetostrictive transducers that are currently being used as well as promising new designs. It presents the basic acoustics as well as the specific acoustics data needed in transducer design and evaluation. A broad range of designs of projectors and hydrophones are described in detail along with methods of modeling, evaluation, and measurement. Analysis of projector and hydrophone transducer arrays, including the effects of mutual radiation impedance and numerical models for elements and arrays, are also covered. The book includes new advances in transducer design and transducer materials and has been completely reorganized to be suitable for use as a textbook, as well as a reference or handbook. The new edition contains updates to the first edition, end-of-chapter exercises, and solutions to select...

  19. Introduction to Piezoelectric Actuators and Transducers

    Science.gov (United States)

    2007-11-02

    1 Introduction to Piezoelectric Actuators and Transducers Kenji Uchino, International Center for Actuators and Transducers, Penn State University...REPORT DATE 00 JUN 2003 2. REPORT TYPE N/A 3. DATES COVERED - 4. TITLE AND SUBTITLE Introduction to Piezoelectric Actuators and Transducers...now used in various fields. The sound source is made from piezoelectric ceramics as well as magnetostrictive materials. Piezoceramics are generally

  20. Finite Element Modeling for Ultrasonic Transducers (Preprint)

    Science.gov (United States)

    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

  1. Be on Pins and Needles

    Institute of Scientific and Technical Information of China (English)

    周立

    2003-01-01

    英语对话:A:It seems you’re on pins and needles today.Anything troubling you?B:Yeah.I don’t know why bad things keep happening to me .You see,mycar was stolen and the warehouse had been broken into.I can’t keep myfinger on the causes of this damned thing.A:There must be someone who had planned that.Do you have a partieularperson in mind?

  2. Estimation of Model Parameters for Steerable Needles

    Science.gov (United States)

    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

  3. Estimation of Model Parameters for Steerable Needles.

    Science.gov (United States)

    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%.

  4. Dry needling - peripheral and central considerations.

    Science.gov (United States)

    Dommerholt, Jan

    2011-11-01

    Dry needling is a common treatment technique in orthopedic manual physical therapy. Although various dry needling approaches exist, the more common and best supported approach targets myofascial trigger points. This article aims to place trigger point dry needling within the context of pain sciences. From a pain science perspective, trigger points are constant sources of peripheral nociceptive input leading to peripheral and central sensitization. Dry needling cannot only reverse some aspects of central sensitization, it reduces local and referred pain, improves range of motion and muscle activation pattern, and alters the chemical environment of trigger points. Trigger point dry needling should be based on a thorough understanding of the scientific background of trigger points, the differences and similarities between active and latent trigger points, motor adaptation, and central sensitize application. Several outcome studies are included, as well as comments on dry needling and acupuncture.

  5. Dimensions of stabident intraosseous perforators and needles.

    Science.gov (United States)

    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.

  6. Pushdown machines for the macro tree transducer

    NARCIS (Netherlands)

    Engelfriet, Joost; Vogler, Heiko

    1986-01-01

    The macro tree transducer can be considered as a system of recursive function procedures with parameters, where the recursion is on a tree (e.g., the syntax tree of a program). We investigate characterizations of the class of tree (tree-to-string) translations which is induced by macro tree transduc

  7. 21 CFR 870.2880 - Ultrasonic transducer.

    Science.gov (United States)

    2010-04-01

    ... structures. This device includes phased arrays and two-dimensional scanning transducers. (b) Classification... 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...

  8. Linearization of resistance thermometers and other transducers

    DEFF Research Database (Denmark)

    Diamond, Joseph M.

    1970-01-01

    Given a resistive transducer which responds directly or indirectly to a physical quantity x, it is shown that the relationship may be linearized by linear methods if and only if both the resistance and conductance of the transducer are concave upward as functions of x. This result applies to eith...

  9. Sliding Mode Control of Steerable Needles

    OpenAIRE

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

    2013-01-01

    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...

  10. Extraordinary Vessels Needling for Vascular Dementia

    Institute of Scientific and Technical Information of China (English)

    YU Jin; LAI Xin-sheng; HUANG Qiu-tang; XIAO Yuan-chun

    2003-01-01

    Purpose To observe the clinical efficacy of extraordinary vessels needling in treating vascular dementia. Method 39 cases vascular dementia were treated by acupoints selected from the eight extraordinary meridians and the time needling techniques such as eight methods of spiritual turtle, in accordance with time period and pattern identifition. Results 2 cases were cured, 30 cases improved and 7 cases failed; the total effective rate was 82.1%. Conclusion Extraordinary vessels needling has positive effects in treating vascular dementia.

  11. Micromachined Ultrasonic Transducers for 3-D Imaging

    DEFF Research Database (Denmark)

    Christiansen, Thomas Lehrmann

    Real-time ultrasound imaging is a widely used technique in medical diagnostics. Recently, ultrasound systems offering real-time imaging in 3-D has emerged. However, the high complexity of the transducer probes and the considerable increase in data to be processed compared to conventional 2-D...... ultrasound imaging results in expensive systems, which limits the more wide-spread use and clinical development of volumetric ultrasound. The main goal of this thesis is to demonstrate new transducer technologies that can achieve real-time volumetric ultrasound imaging without the complexity and cost...... of state-of-the-art 3-D ultrasound systems. The focus is on row-column addressed transducer arrays. This previously sparsely investigated addressing scheme offers a highly reduced number of transducer elements, resulting in reduced transducer manufacturing costs and data processing. To produce...

  12. Freehand biopsy guided by electromagnetic needle tracking

    DEFF Research Database (Denmark)

    Ewertsen, C; Nielsen, Marie Kristina Rue; Nielsen, M Bachmann

    2011-01-01

    To evaluate the overall accuracy and time spent on biopsy guided by electromagnetic needle tracking in a phantom compared with the standard technique of US-guided biopsy with an attached steering device. Furthermore, to evaluate off-plane biopsy guided by needle tracking.......To evaluate the overall accuracy and time spent on biopsy guided by electromagnetic needle tracking in a phantom compared with the standard technique of US-guided biopsy with an attached steering device. Furthermore, to evaluate off-plane biopsy guided by needle tracking....

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

    OpenAIRE

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

    2008-01-01

    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 include...

  14. A subcutaneous Raman needle probe.

    Science.gov (United States)

    Day, John C C; Stone, Nicholas

    2013-03-01

    Raman spectroscopy is a powerful tool for studying the biochemical composition of tissues and cells in the human body. We describe the initial results of a feasibility study to design and build a miniature, fiber optic probe incorporated into a standard hypodermic needle. This probe is intended for use in optical biopsies of solid tissues to provide valuable information of disease type, such as in the lymphatic system, breast, or prostate, or of such tissue types as muscle, fat, or spinal, when identifying a critical injection site. The optical design and fabrication of this probe is described, and example spectra of various ex vivo samples are shown.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    ... News Physician Resources Professions Site Index A-Z Ultrasound-Guided Fine Needle Aspiration Biopsy of the Thyroid ... Needle Aspiration Biopsy of the Thyroid? What is Ultrasound-Guided Fine Needle Aspiration Biopsy of the Thyroid? ...

  17. Modeling of functionally graded piezoelectric ultrasonic transducers.

    Science.gov (United States)

    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.

  18. Electrical modeling of dielectric elastomer stack transducers

    Science.gov (United States)

    Haus, Henry; Matysek, Marc; Moessinger, Holger; Flittner, Klaus; Schlaak, Helmut F.

    2013-04-01

    Performance of dielectric elastomer transducers (DEST) depends on mechanical and electrical parameters. For designing DEST it is therefore necessary to know the influences of these parameters on the overall performance. We show an electrical equivalent circuit valid for a transducer consisting of multiple layers and derive the electrical parameters of the circuit depending on transducers geometry and surface resistivity of the electrodes. This allows describing the DESTs dynamic behavior as a function of fabrication (layout, sheet and interconnection resistance), material (breakdown strength, permittivity) and driving (voltage) parameters. Using this electrical model transfer function and cut-off frequency are calculated, describing the influence of transducer capacitance, resistance and driving frequency on the achievable actuation deflection. Furthermore non ideal boundary effects influencing the capacitance value of the transducer are investigated by an electrostatic simulation and limits for presuming a simple plate capacitor model for calculating the transducer capacitance are derived. Results provide the plate capacitor model is a valid assumption for typical transducer configurations but for certain aspect ratios of electrode dimensions to dielectric thickness -- arising e.g. in the application of tactile interfaces -- the influence of boundary effects is to be considered.

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

    Science.gov (United States)

    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.

  20. Seismic transducer modeling using ABAQUS

    Energy Technology Data Exchange (ETDEWEB)

    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.

  1. Investigating the Effects of Three Needling Parameters (Manipulation, Retention Time, and Insertion Site on Needling Sensation and Pain Profiles: A Study of Eight Deep Needling Interventions

    Directory of Open Access Journals (Sweden)

    Bertrand Y. K. Loyeung

    2013-01-01

    Full Text Available Introduction. In traditional Chinese acupuncture, needle sensation (deqi is purported to contribute to a therapeutic outcome. While researchers have attempted to define deqi qualitatively, few have examined the effects of needling parameters on its intensity. Methods. 24 healthy subjects completed eight interventions scheduled at least one week apart, which involved manual acupuncture to LI4 or a designated nonacupoint (NAP on the hand, with real or simulated manipulation each three minutes and needle retentions of one or 21 minutes. Intensities of needling sensation and pain were reported every three minutes and sensation qualities were reported post-intervention. Results. Immediately after needle insertion, similar levels of mean needle sensation and of pain were reported independent of intervention. At subsequent measurement times, only two interventions (one at LI4 and one at NAP maintained statistically significantly elevated needle sensation and pain scores and reported higher numbers of needle sensation descriptors. For both, the needle was retained for 21 minutes and manipulated every three minutes. Neither intervention differed significantly in terms of levels of pain, and needle sensation or numbers and qualities of needle sensation described. Conclusion. In this group of healthy subjects, the initial needling for all eight interventions elicited similar levels of needle sensation and pain. These levels were only maintained if there was ongoing of needle manipulation and retention of the needle. By contrast, the strength of needle sensation or pain experienced was independent of insertion site.

  2. Freehand biopsy guided by electromagnetic needle tracking

    DEFF Research Database (Denmark)

    Ewertsen, C; Nielsen, Marie Kristina Rue; Nielsen, M Bachmann

    2011-01-01

    To evaluate the overall accuracy and time spent on biopsy guided by electromagnetic needle tracking in a phantom compared with the standard technique of US-guided biopsy with an attached steering device. Furthermore, to evaluate off-plane biopsy guided by needle tracking....

  3. Needle exchange programs in prisons in Spain.

    Science.gov (United States)

    Menoyo, C; Zulaica, D; Parras, F

    2000-01-01

    On 11 July 2000, at the XIII International AIDS Conference in Durban, yet another country--Spain--presented evidence that needle exchange programs in prisons work. We reproduce here the text of the presentation entitled "Needle Exchange Program at the Bilbao Prison, Spain: Two Years of Experience (1997-1999)."

  4. HOW TO REDUCE NEEDLE INSERTION INDUCED PAIN

    Institute of Scientific and Technical Information of China (English)

    王斌; 董莉

    2001-01-01

    Acupuncture needle insertion always results in pain in the local area due to stimulating the free nerve endings—algesireceptors of the skin. In spite of mildness, this pain may induce many patients' fright, and thus, hinders more extensive application of acupuncture. In the present paper, the author introduces some methods for reducing needle insertion induced pain.

  5. Fine needle aspiration cytology of rectal masses.

    Science.gov (United States)

    Kochhar, R; Rajwanshi, A; Wig, J D; Gupta, N M; Kesiezie, V; Bhasin, D K; Malik, A K; Gupta, S K; Mehta, S K

    1990-01-01

    This paper describes the results of transproctoscopic fine needle aspiration cytology in the diagnosis of rectal lesions. Fifty one consecutive patients referred with a presumptive diagnosis of rectal mass were subjected to proctoscopic examination when fine needle aspiration cytology, brush cytology and biopsy samples were taken. Of the 30 patients of malignancy of rectum in whom all the three sampling techniques were applied, the biopsy was positive in 27 (90%), brush cytology in 25 (83.3%) and fine needle aspiration cytology in 29 (96.6%). A combination of fine needle aspiration cytology with brush cytology gave a positive yield in 96.6% while that fine needle aspiration cytology with brush cytology gave a yield of 100%. Fine needle aspiration cytology was most helpful in infiltrative tumours. All 10 patients with secondaries in the pouch of Douglas or rectovesical pouch, and the single patient with submucosal rectal carcinoma were correctly diagnosed at fine needle aspiration cytology. There were no false positive results with fine needle aspiration cytology and no complications were encountered with the procedure. Images Figure 1 Figure 2 Figure 3 PMID:2323600

  6. An Elementary Account of Needle Insertion

    Institute of Scientific and Technical Information of China (English)

    张文兵; 霍则军

    2004-01-01

    @@ Based on the authors' clinical and personal experiences, several pain-inducing factors easily to be ignored by the operators when quick needle insertion is applied, and the authors' first invented slow painless needle insertion method are introduced in the article.

  7. Hybrid piezoelectric energy harvesting transducer system

    Science.gov (United States)

    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.

  8. Compact Orthomode Transducers Using Digital Polarization Synthesis

    CERN Document Server

    Morgan, Matthew A; Boyd, Tod A

    2010-01-01

    In this paper we present a novel class of compact orthomode transducers which use digital calibration to synthesize the desired polarization vectors while maintaining high isolation and minimizing mass and volume. These digital orthomode transducers consist of an arbitrary number of planar probes in a circular waveguide, each of which is connected to an independent receiver chain designed for stability of complex gain. The outputs of each receiver chain are then digitized and combined numerically with calibrated, complex coefficients. Measurements on two prototype digital orthomode transducers, one with three probes and one with four, show better than 50 dB polarization isolation over a 10 C temperature range with a single calibration.

  9. Performance of Honeywell silicon pressure transducers

    Digital Repository Service at National Institute of Oceanography (India)

    VijayKumar, K.; Joseph, A.; Desai, R.G.P.; Nagvekar, S.; Prabhudesai, S.; Damodaran, V.

    time, via respective pressure channeling tubes, thereby allowing all the transducers to be stabilized simultaneously after a step change in the input pressure. 4. Performance Evaluation The parameters considered in the present work to assess...

  10. Micromachined Integrated Transducers for Ultrasound Imaging

    DEFF Research Database (Denmark)

    la Cour, Mette Funding

    project and collaboration with a lot of partners to improve medical ultrasound imaging. The focus in this part of the project is to design, fabricate and characterize 1D CMUT arrays. Two versions of 1D transducers are made, one at Stanford University and one at DTU. Electrical and acoustical......, but two possible solutions are suggested. Two devices are assembled into probe handles and initial acoustical characterizations are promising. Even though the sensitivity is currently low, images are produced with recognizable features both on phantoms and volunteers. It can be mentioned that a -6 d......The purpose of this project is to develop capacitive micromachined ultrasonic transducers (CMUTs) for medical imaging. Medical ultrasound transducers used today are fabricated using piezoelectric materials and bulk processing. To fabricate transducers capable of delivering a higher imaging...

  11. Portable high precision pressure transducer system

    Science.gov (United States)

    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.

  12. Design considerations for piezoelectric polymer ultrasound transducers.

    Science.gov (United States)

    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.

  13. Conductometric transducers for enzyme-based biosensors.

    Science.gov (United States)

    Mikkelsen, S R; Rechnitz, G A

    1989-08-01

    The use of alternating current conductometric transducers in biosensing devices has been investigated for urea and D-amino acid sensors using the enzyme systems urease and D-amino acid oxidase/catalase. Transducers with copper and platinum electrodes were constructed and characterized, and two enzyme immobilization methods were tested. Detection limits of 1 x 10(-6)M and linear ranges of 2 orders of magnitude were routinely achieved for these model sensors with enzymes covalently immobilized on collagen films.

  14. Comparison of piezoresistive and capacitive ultrasonic transducers

    Science.gov (United States)

    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.

  15. The Biological Safety of Stainless Steel Needles Used in Warm-Needling

    Directory of Open Access Journals (Sweden)

    Sabina Lim

    2010-01-01

    Full Text Available 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.

  16. [Inductance transducers for borderline localization of metallic foreign bodies].

    Science.gov (United States)

    Pudov, V I; Reutov, Iu Ia; Korotkikh, S A

    1996-01-01

    The paper outlines the advantages and disadvantages of a ferroprobe inductance transducer used in the borderline localization of a foreign ferromagnetic body. To eliminate the ferroprobe transducer-inherent disadvantages, a whirl-current inductance transducer has been developed. The transducer localizes a foreign nonferromagnetic and ferromagnetic body in its borderline localization in the eye and in the whole body.

  17. Needle muscle biopsy and its application

    Directory of Open Access Journals (Sweden)

    Meng-long CHEN

    2015-07-01

    Full Text Available Needle muscle biopsy is a straightforward and reliable minimally-invasive technique. During the past century, the needle biopsy can provide adequate samples and the technique has gradually gained wider acceptance. Compared with open biopsy, needle biopsy is less traumatic, with low rate of complications, and is suitable for the identifications and evaluations of muscular dystrophy, inflammatory myopathies and systemic diseases involving muscles, specially for infants and young children. Domestic insiders should be encouraged to apply this technique. DOI: 10.3969/j.issn.1672-6731.2015.06.003 

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kuang Yuanwen [South China Botanical Garden, Chinese Academy of Sciences, 510650 Guangzhou (China)]. E-mail: kuangyw@scbg.ac.cn; Wen Dazhi [South China Botanical Garden, Chinese Academy of Sciences, 510650 Guangzhou (China)]. E-mail: dzwen@scbg.ac.cn; Zhou Guoyi [South China Botanical Garden, Chinese Academy of Sciences, 510650 Guangzhou (China)]. E-mail: gyzhou@scbg.ac.cn; Liu Shizhong [South China Botanical Garden, Chinese Academy of Sciences, 510650 Guangzhou (China)]. E-mail: lsz@scbg.ac.cn

    2007-02-15

    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. - Pine needle sections as bioindicator for heavy metals and nutrient deficiency particularly needle sheath for particle pollutants.

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

    Energy Technology Data Exchange (ETDEWEB)

    Kuang Yuanwen [Institute of Ecology, South China Botanical Garden, Chinese Academy of Sciences, 510650 Guangzhou (China)]. E-mail: kuangyw@scbg.ac.cn; Wen Dazhi [Institute of Ecology, South China Botanical Garden, Chinese Academy of Sciences, 510650 Guangzhou (China)]. E-mail: dzwen@scbg.ac.cn; Zhou Guoyi [Institute of Ecology, South China Botanical Garden, Chinese Academy of Sciences, 510650 Guangzhou (China)]. E-mail: gyzhou@scbg.ac.cn; Liu Shizhong [Institute of Ecology, South China Botanical Garden, Chinese Academy of Sciences, 510650 Guangzhou (China)]. E-mail: lsz@scbg.ac.cn

    2007-01-15

    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. - Pine needle sections as bioindicator for heavy metals and nutrient deficiency particularly needle sheath for particle pollutants.

  4. Pine needle abortion biomarker detected in bovine fetal fluids

    Science.gov (United States)

    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...

  5. Some Strip Contributions to Transducer Design and Analysis

    Science.gov (United States)

    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

  6. Sliding Mode Control of Steerable Needles

    Science.gov (United States)

    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

  7. Biopsy needle detection in transrectal ultrasound.

    Science.gov (United States)

    Ayvaci, Alper; Yan, Pingkun; Xu, Sheng; Soatto, Stefano; Kruecker, Jochen

    2011-01-01

    Using the fusion of pre-operative MRI and real time intra-procedural transrectal ultrasound (TRUS) to guide prostate biopsy has been shown as a very promising approach to yield better clinical outcome than the routinely performed TRUS only guided biopsy. In several situations of the MRI/TRUS fusion guided biopsy, it is important to know the exact location of the deployed biopsy needle, which is imaged in the TRUS video. In this paper, we present a method to automatically detect and segment the biopsy needle in TRUS. To achieve this goal, we propose to combine information from multiple resources, including ultrasound probe stability, TRUS video background model, and the prior knowledge of needle orientation and position. The proposed algorithm was tested on TRUS video sequences which have in total more than 25,000 frames. The needle deployments were successfully detected and segmented in the sequences with high accuracy and low false-positive detection rate.

  8. A Multi-Layered Needle Injection Simulator.

    Science.gov (United States)

    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.

  9. Sliding Mode Control of Steerable Needles.

    Science.gov (United States)

    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.

  10. Inverse Kinematics of Concentric Tube Steerable Needles

    Science.gov (United States)

    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

  11. Missing Broken Needle During Caesarean Section

    Directory of Open Access Journals (Sweden)

    Chandana Das

    2009-09-01

    Full Text Available Breakage of the needle and missing while repairing the uterine wound during cesarean section is an uncommon event. Subsequently it was removed under fluoroscopic guidance on the 7th postoperative day

  12. High temperature, high power piezoelectric composite transducers.

    Science.gov (United States)

    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.

  13. Finite element model of needle electrode sensitivity

    Science.gov (United States)

    Høyum, P.; Kalvøy, H.; Martinsen, Ø. G.; Grimnes, S.

    2010-04-01

    We used the Finite Element (FE) Method to estimate the sensitivity of a needle electrode for bioimpedance measurement. This current conducting needle with insulated shaft was inserted in a saline solution and current was measured at the neutral electrode. FE model resistance and reactance were calculated and successfully compared with measurements on a laboratory model. The sensitivity field was described graphically based on these FE simulations.

  14. Dry needling versus acupuncture: the ongoing debate.

    Science.gov (United States)

    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.

  15. The simulation model of planar electrochemical transducer

    Science.gov (United States)

    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. Needle-in-Needle Technique for Percutaneous Retrieval of a Fractured Biopsy Needle during CT-Guided Biopsy of the Thoracic Spine.

    Science.gov (United States)

    Shaikh, Hamza; Thawani, Jayesh; Pukenas, Bryan

    2014-10-31

    Common complications related to CT-guided percutaneous thoracic bone biopsy procedures include pneumothorax and muscular hematoma. Serious, but rare complications include paralysis, nerve injury, CSF leak, and aortic injury. Device failure has not been well documented in the literature. We discuss our experience with biopsy needle breakage during retrieval of a core specimen and the technique used to help retrieve an embedded needle using a CT fluoroscopic-guided, needle-in-needle approach. A 43 year-old man with Stage IIIa NSCLC was found to have a T11 vertebral body lesion as seen on PET, CT, and MR imaging. The patient underwent a CT-guided biopsy in the prone position. The T11 vertebral body was localized and cannulated using the percutaneous Bonopty(®) (Apriomed, Upsala, Sweden) needle device. After fine needle aspiration samples were obtained, a core needle biopsy was attempted with a 16-gauge device. The needle fractured 4 cm deep to the skin during removal of a sclerotic lesion, leaving a retained portion within the pedicle and vertebral body. Using CT-guided fluoroscopy, a large diameter Murphy M2 needle was advanced over the distal portion of the fractured Bonopty needle. The Murphy M2 needle was advanced distal to the tip of the Bonopty needle and removed, capturing the broken Bonopty penetration needle along with a core specimen. Larger-bore biopsy needle systems and/or a coaxial system should be used to perform core biopsies in sclerotic lesions to prevent device fracture. If there is device fracture, a larger-bore needle may be used to help capture the fractured needle and prevent open surgery.

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

    Science.gov (United States)

    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

  18. Methods for segmenting curved needles in ultrasound images.

    Science.gov (United States)

    Okazawa, Stephen H; Ebrahimi, Richelle; Chuang, Jason; Rohling, Robert N; Salcudean, Septimiu E

    2006-06-01

    Ultrasound-guided percutaneous needle insertions are widely used techniques in current clinical practice. Some of these procedures have a high degree of difficulty because of poor observability of the needle in the ultrasound image. There have been recent efforts to improve guidance by computer assisted needle detection. These software techniques are often limited by not representing needle curvature. We present two methods to detect the needle in 2D ultrasound that specifically address needle curvature. Firstly, we demonstrate a real-time needle segmentation algorithm based on the Hough transform which detects the needle and represents its curved shape. Secondly, we demonstrate how a new coordinate transformation can transform detection of a curved needle to a linear fit. These methods are demonstrated on ultrasound and photographic images.

  19. Needle deflection estimation using fusion of electromagnetic trackers.

    Science.gov (United States)

    Sadjadi, H; Hashtrudi-Zaad, K; Fichtinger, G

    2012-01-01

    We present a needle deflection estimation method to compensate for needle bending during insertion into deformable tissue. We combine a kinematic needle deflection estimation model, electromagnetic (EM) trackers, and a Kalman filter (KF). We reduce the impact of error from the needle deflection estimation model by using the fusion of two EM trackers to report the approximate needle tip position in real-time. One reliable EM tracker is installed on the needle base, and estimates the needle tip position using the kinematic needle deflection model. A smaller but much less reliable EM tracker is installed on the needle tip, and estimates the needle tip position through direct noisy measurements. Using a KF, the sensory information from both EM trackers is fused to provide a reliable estimate of the needle tip position with much reduced variance in the estimation error. We then implement this method to compensate for needle deflection during simulated prostate cancer brachytherapy needle insertion. At a typical maximum insertion depth of 15 cm, needle tip mean estimation error was reduced from 2.39 mm to 0.31 mm, which demonstrates the effectiveness of our method, offering a clinically practical solution.

  20. Transducer-based evaluation of tremor.

    Science.gov (United States)

    Haubenberger, Dietrich; Abbruzzese, Giovanni; Bain, Peter G; Bajaj, Nin; Benito-León, Julián; Bhatia, Kailash P; Deuschl, Günther; Forjaz, Maria João; Hallett, Mark; Louis, Elan D; Lyons, Kelly E; Mestre, Tiago A; Raethjen, Jan; Stamelou, Maria; Tan, Eng-King; Testa, Claudia M; Elble, Rodger J

    2016-09-01

    The International Parkinson and Movement Disorder Society established a task force on tremor that reviewed the use of transducer-based measures in the quantification and characterization of tremor. Studies of accelerometry, electromyography, activity monitoring, gyroscopy, digitizing tablet-based measures, vocal acoustic analysis, and several other transducer-based methods were identified by searching PubMed.gov. The availability, use, acceptability, reliability, validity, and responsiveness were reviewed for each measure using the following criteria: (1) used in the assessment of tremor; (2) used in published studies by people other than the developers; and (3) adequate clinimetric testing. Accelerometry, gyroscopy, electromyography, and digitizing tablet-based measures fulfilled all three criteria. Compared to rating scales, transducers are far more sensitive to changes in tremor amplitude and frequency, but they do not appear to be more capable of detecting a change that exceeds random variability in tremor amplitude (minimum detectable change). The use of transducer-based measures requires careful attention to their limitations and validity in a particular clinical or research setting. © 2016 International Parkinson and Movement Disorder Society.

  1. Pressure compensated transducer system with constrained diaphragm

    Science.gov (United States)

    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.

  2. Broadband, High-Temperature Ultrasonic Transducer

    Science.gov (United States)

    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.

  3. Analysis of multifrequency langevin composite ultrasonic transducers.

    Science.gov (United States)

    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.

  4. Medically relevant ElectroNeedle technology development.

    Energy Technology Data Exchange (ETDEWEB)

    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.

  5. Optical Coherence Tomography in a Needle Format

    Science.gov (United States)

    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.

  6. A wideband combined transducer for measuring system in sound tube

    Institute of Scientific and Technical Information of China (English)

    PAN Yaozong; MO Xiping; LIU Yongping; CUI Zheng; ZHANG Tonggen

    2012-01-01

    A wideband transducer for sound tube system is presented, which combines longitudinal transducer and Class IV flextensional transducer to improve the performance at low frequency and broaden the working band. The equivalent circuit is obtained and used to analyze the coupling mechanism between longitudinal transducer and flextensional transducer. A prototype of the transducer is developed after optimizing the electro-acoustic performances by Finite Element Method. The standing wave in the sound tube stimulated by this transducer has been studied and the sound absorbing coefficients of two acoustic materials samples are measured using this sound tube, which shows that the transducer can meet the requirements of acoustic material measurement with the working band ranging from 1.4 kHz to 23 kHz.

  7. Perception and Action in Teleoperated Needle Insertion.

    Science.gov (United States)

    Nisky, I; Pressman, A; Pugh, C M; Mussa-Ivaldi, F A; Karniel, A

    2011-01-01

    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 a 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.

  8. Needle-free insulin drug delivery

    Directory of Open Access Journals (Sweden)

    Patni Preeti

    2006-01-01

    Full Text Available For most patients with type 1 diabetes, the worst part of the disease is to tolerate needle after needle, both for glucose measurement and to deliver insulin. In the last two decades, concept of insulin therapy by multiple-dose injection has undergone a miraculous change. Needle-free insulin delivery appeared to be a wonderful approach, and its allure rested in being comfortable and safe. In today′s era, insulin delivery by alternative route is a topic of current interest in the design of drug delivery system. Major global pharmaceutical companies are showing encouraging progress in their attempts to develop alternative insulin delivery technologies. Many such drug delivery systems have been developed for oral, buccal and nasal route. This review article discusses, in brief, the novel and emerging technologies that are in pipeline, including insulin inhalers, insulin spray, insulin pill, insulin analogues, insulin complement, islet cell transplant, implantable insulin pumps and guardian continuous glucose monitoring system.

  9. TREATMENT OF EPIGASTRIC PAIN WITH SUBCUTANEOUS NEEDLING

    Institute of Scientific and Technical Information of China (English)

    GUO Jia-tu

    2006-01-01

    @@ Subcutaneous needling is a new therapeutic method which is based on the features of the meridian-collateral theory of cutaneous regions in traditional Chinese medicine and the neurohumeral theory and skin anatomy of modern medicine and is of the features of "fixed meridian but not fixed acupoints", "micro stimulation", and "subcutaneous needling with filiform needles" to achieve the goal of treating diseases. This method is indicated clinically to the analgesia and relaxation of spasm especially the pain caused by the disorders of the internal organs and marked therapeutic effect has been obtained. With method, 150 cases of epigastric pain were treated by our department and the total effective rate was over 90%. It is presented herein below.

  10. Photoacoustic tomography of monkey brain using virtual point ultrasonic transducers

    OpenAIRE

    Nie, Liming; Guo, Zijian; Wang, Lihong V.

    2011-01-01

    A photoacoustic tomography system (PAT) using virtual point ultrasonic transducers was developed and applied to image a monkey brain. The custom-built transducers provide a 10-fold greater field-of-view (FOV) than finite-aperture unfocused transducers as well as an improved signal-to-noise ratio (SNR) and reduced artifacts rather than negative-lens transducers. Their tangential resolution, radial resolution, and (SNR) improvements were quantified using tissue phantoms. Our PAT system can achi...

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

    Science.gov (United States)

    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

  12. An ultrasonic--EMG transducer for biodynamic research.

    Science.gov (United States)

    Watkin, K L; Minifie, F D; Kennedy, J G

    1978-03-01

    This note describes a newly developed single-element muscle action potential/motion transducer. The transcuer was specially designed for speech research. Techniques for use of the transducer are described. Sample data are presented illustrating the capability of the transducer, and applications of the device are discussed.

  13. Analysis of the NovoTwist pen needle in comparison with conventional screw-thread needles.

    Science.gov (United States)

    Aye, Tandy

    2011-11-01

    Administration of insulin via a pen device may be advantageous over a vial and syringe system. Hofman and colleagues introduce a new insulin pen needle, the NovoTwist, to simplify injections to a small group of children and adolescents. Their overall preferences and evaluation of the handling of the needle are reported in the study. This new needle has the potential to ease administration of insulin via a pen device that may increase both the use of a pen device and adherence to insulin therapy.

  14. Winging of the scapula: An unusual complication of needle thoracocentesis.

    Science.gov (United States)

    Faruqi, S; Raychaudhuri, C; Thirumaran, M; Blaxill, P

    2008-07-01

    Needle thoracocentesis is a common interventional procedure and is generally considered to be safe. Major complications associated with this procedure are uncommon. Here we describe a rare instance of winging of the scapula following needle thoracocentesis.

  15. The Needling Technique and Clinical Application of Point Zhibian

    Institute of Scientific and Technical Information of China (English)

    张远东

    2004-01-01

    @@ The Needling Technique The patient is asked to lie in a lateral or prone position. A No. 28 filiform needle of 3 cun is inserted perpendicularly into the point Zhibian (BL 54), with the direction of the needle tip varying according to the different conditions of the diseases. The needle can be directed in three directions, the first along the sciatic nerve; the second pointing to the genitals; and the third pointing to the anus. The reinforcing,reducing, or even needling manipulation can be used,and the needling depth can be deep or superficial.The needling can also be applied in combination with the warm-needle, cupping, and point-injection.

  16. Preparation of (non-)aqueous dispersins of colloidal boehmite needles

    NARCIS (Netherlands)

    Buining, P.A.; Pathmamanoharan, C.; Philipse, A.P.; Lekkerkerker, H.N.W.

    1993-01-01

    A novel hydrothermal alkoxide method is presented for the preparation of stable, aqueousdispersions of fairly monodisperse, charged colloidal boehmite needles. A polymer coating procedure for the needles is described which leads to sterically stabilized dispersions in organic solvents.

  17. Self-Aligned Interdigitated Transducers for Acoustofluidics

    Directory of Open Access Journals (Sweden)

    Zhichao Ma

    2016-11-01

    Full Text Available The surface acoustic wave (SAW is effective for the manipulation of fluids and particles at microscale. The current approach of integrating interdigitated transducers (IDTs for SAW generation into microfluidic channels involves complex and laborious microfabrication steps. These steps often require full access to clean room facilities and hours to align the transducers to the precise location. This work presents an affordable and innovative method for fabricating SAW-based microfluidic devices without the need for clean room facilities and alignment. The IDTs and microfluidic channels are fabricated using the same process and thus are precisely self-aligned in accordance with the device design. With the use of the developed fabrication approach, a few types of different SAW-based microfluidic devices have been fabricated and demonstrated for particle separation and active droplet generation.

  18. New piezoelectric transducers for therapeutic ultrasound.

    Science.gov (United States)

    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.

  19. Orbital angular momentum-entanglement frequency transducer

    CERN Document Server

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

    2016-01-01

    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 photons 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 nm to 525 nm for OAM qubits, OAMpolarization 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 betwe...

  20. Electromechanical transducer for acoustic telemetry system

    Energy Technology Data Exchange (ETDEWEB)

    Drumheller, Douglas S. (Cedar Crest, NM)

    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.

  1. Electromechanical transducer for acoustic telemetry system

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. Optomechanical transducers for quantum information processing

    CERN Document Server

    Stannigel, K; Sørensen, A S; Lukin, M D; Zoller, P

    2011-01-01

    We discuss the implementation of optical quantum networks where the interface between stationary and photonic qubits is realized by optomechanical transducers [K. Stannigel et al., PRL 105, 220501 (2010)]. This approach does not rely on the optical properties of the qubit and thereby enables optical quantum communication applications for a wide range of solid-state spin- and charge-based systems. We present an effective description of such networks for many qubits and give a derivation of a state transfer protocol for long-distance quantum communication. We also describe how to mediate local on-chip interactions by means of the optomechanical transducers that can be used for entangling gates. We finally discuss experimental systems for the realization of our proposal.

  3. Needle Path Planning for Autonomous Robotic Surgical Suturing.

    Science.gov (United States)

    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.

  4. Characterization of transducer cavities to oscillatory inputs

    Energy Technology Data Exchange (ETDEWEB)

    Rogers, J.D.; Hollingshead, J.R.

    1993-12-31

    The design and use of measurement systems must ensure that the data are not computed by the measurement system. A wide variety of sources can be responsible for compromising the integrity of test data. Among the sources of error are transducer calibration errors, signal conditioning problems, recording problems, and characteristics of the mechanical system which introduce errors. In this paper, the characteristics of an acoustic cavity are discussed as they apply to a pressure measurement problem.

  5. Transducer Analysis and ATILA++ Model Development

    Science.gov (United States)

    2016-10-10

    the ATILA finite element software package. This will greatly enhance the state-of-the-art in transducer performance prediction and provide a tool...The free dielectric constants for soft crystals show significant change with preload which affects device impedance and amplifier considerations...under Static Preload An apparatus and software control system have been fabricated and developed for evaluating the behavior of materials under high

  6. Updated Results of Ultrasonic Transducer Irradiation Test

    Energy Technology Data Exchange (ETDEWEB)

    Daw, Joshua; Palmer, Joe [Idaho National Laboratory, P.O. Box 1625, MS 4112, Idaho Falls, ID, 38415-3840 (United States); Ramuhalli, Pradeep; Keller, Paul; Montgomery, Robert [Pacific Northwest National Laboratory, 902 Battelle Blvd. Richland, WA, 99354 (United States); Chien, Hual-Te [Argonne National Laboratory, 9700 S. Cass Avenue Argonne, IL, 60439 (United States); Tittmann, Bernhard; Reinhardt, Brian [Pennsylvania State University, 212 Earth and Engr. Sciences Building, University Park, PA, 16802 (United States); Kohse, Gordon [Massachusetts Institute of Technology, 77 Massachusetts Ave. Cambridge, MA 02139 (United States); Rempe, Joy [Rempe and Associates, LLC, 360 Stillwater, Idaho Falls, ID 83404 (United States); Villard, J.F. [Commissariat a l' energie atomique et aux energies alternatives, Centre d' etudes de Cadarache, 13108 Saint-Paul-lez-Durance (France)

    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)

  7. Stress Sensors and Signal Transducers in Cyanobacteria

    Directory of Open Access Journals (Sweden)

    Sergey Kryazhov

    2010-03-01

    Full Text Available In living cells, the perception of environmental stress and the subsequent transduction of stress signals are primary events in the acclimation to changes in the environment. Some molecular sensors and transducers of environmental stress cannot be identified by traditional and conventional methods. Based on genomic information, a systematic approach has been applied to the solution of this problem in cyanobacteria, involving mutagenesis of potential sensors and signal transducers in combination with DNA microarray analyses for the genome-wide expression of genes. Forty-five genes for the histidine kinases (Hiks, 12 genes for serine-threonine protein kinases (Spks, 42 genes for response regulators (Rres, seven genes for RNA polymerase sigma factors, and nearly 70 genes for transcription factors have been successfully inactivated by targeted mutagenesis in the unicellular cyanobacterium Synechocystis sp. PCC 6803. Screening of mutant libraries by genome-wide DNA microarray analysis under various stress and non-stress conditions has allowed identification of proteins that perceive and transduce signals of environmental stress. Here we summarize recent progress in the identification of sensory and regulatory systems, including Hiks, Rres, Spks, sigma factors, transcription factors, and the role of genomic DNA supercoiling in the regulation of the responses of cyanobacterial cells to various types of stress.

  8. Enhanced C-band Coaxial Orthomode Transducer

    Directory of Open Access Journals (Sweden)

    S. I. Piltyay

    2014-09-01

    Full Text Available Introduction. In this paper a novel configuration of wideband coherent coaxial OMT is presented. General Design of an Orthomode Transducer. The OMT consists of elements of 3 main types: a turnstile junction between coaxial quad-ridged waveguide and 4 coaxial transmission lines; 4 coaxial transmission lines of LMR400 type; 2 antiphase power combiners/dividers. A Turnstile Junction Optimization. The optimization of a turnstile junction has been performed. Its minimized reflection coefficient is less than −28 dB in the operation frequency band 3.4–5.4 GHz. A Wideband Antiphase Power Combiner/Divider. The optimization of an antiphase power combiner/divider has been performed. Its minimized reflection coefficient is less than −38 dB. Characteristics of Coaxial Orthomode Transducer Developed. The simulation of OMT characteristics has been performed using CST Design Studio software. Conclusions. A wideband coherent coaxial orthomode transducer has been developed for the operation frequency band 3.4–5.4 GHz. In this frequency band the reflection coefficient of OMT is less than −24 dB and its crosspolar isolation exceeds 38 dB. The wideband coaxial OMT developed can be used in dual-polarized multiband antennas for satellite telecommunications and for radioastronomy.

  9. Comparative Study of Wear Resistance of Sewing Needles

    Institute of Scientific and Technical Information of China (English)

    FEI Dong-ye; ZHU Shi-gen

    2002-01-01

    Poor wearability is the most serious problem of domestic sewing needle, which is the main reason for their short service lives. The influences of needle materials,microstructures and manufacturing technologies on the wear resistance are analyzed in comparison with foreign sewing needles. A series of suitable measures are proposed to improve the wear resistance.

  10. Robotic needle steering: design, modeling, planning, and image guidance

    NARCIS (Netherlands)

    Cowan, Noah J.; Goldberg, Ken; Chirikjian, Gregory S.; Fichtinger, Gabor; Alterovitz, Ron; Reed, Kyle B.; Kallem, Vinutha; Park, Wooram; Misra, Sarthak; Okamura, Allison M.; Rosen, Jacob; Hannaford, Blake; Satava, Richard M.

    2010-01-01

    This chapter describes how advances in needle design, modeling, planning, and image guidance make it possible to steer flexible needles from outside the body to reach specified anatomical targets not accessible using traditional needle insertion methods. Steering can be achieved using a variety of m

  11. Mechanics of Flexible Needles Robotically Steered through Soft Tissue

    NARCIS (Netherlands)

    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

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

    Science.gov (United States)

    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.

  13. A Neoprene with Optimized Bondability for Sonar Transducer Applications

    Science.gov (United States)

    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

  14. Bubble Growth and Detachment from a Needle

    Science.gov (United States)

    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.

  15. Buffon Needle Problem Application to Space Exploration

    CERN Document Server

    Sedelnikov, A V

    2010-01-01

    In this article the possibility of application of classical Buffon needle problem to the investigation of orientation engine firing problem has been investigated. Such an approach makes it possible to get a reliable EP of this undesired event without using a more complicated analysis.

  16. Relationship between needle phobia and dental anxiety

    NARCIS (Netherlands)

    Majstorovic, M.; Veerkamp, J.S.J.

    2004-01-01

    Purpose: This cross-sectional study aimed to explain the nature of needle phobia and its relationship in dental phobic children with evidence on age-related differences. Methods: The study used 2,865 patients (52% boys, 48% girls), 4 to 11 years old (mean=7.18 years). The patient sample included ran

  17. Biocompatible 3D printed magnetic micro needles

    KAUST Repository

    Kavaldzhiev, Mincho

    2017-01-30

    Biocompatible functional materials play a significant role in drug delivery, tissue engineering and single cell analysis. We utilized 3D printing to produce high aspect ratio polymer resist microneedles on a silicon substrate and functionalized them by iron coating. Two-photon polymerization lithography has been used for printing cylindrical, pyramidal, and conical needles from a drop cast IP-DIP resist. Experiments with cells were conducted with cylindrical microneedles with 630 ± 15 nm in diameter with an aspect ratio of 1:10 and pitch of 12 μm. The needles have been arranged in square shaped arrays with various dimensions. The iron coating of the needles was 120 ± 15 nm thick and has isotropic magnetic behavior. The chemical composition and oxidation state were determined using energy electron loss spectroscopy, revealing a mixture of iron and Fe3O4 clusters. A biocompatibility assessment was performed through fluorescence microscopy using calcein/EthD-1 live/dead assay. The results show a very high biocompatibility of the iron coated needle arrays. This study provides a strategy to obtain electromagnetically functional microneedles that benefit from the flexibility in terms of geometry and shape of 3D printing. Potential applications are in areas like tissue engineering, single cell analysis or drug delivery.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  20. Silver doped 0.9PMN-PT-0.1PZT composite films for very high frequency ultrasonic transducer applications

    Energy Technology Data Exchange (ETDEWEB)

    Hsu, Hsiu-Sheng [University of Southern California, Department of Biomedical Engineering and NIH Transducer Resource Center, Los Angeles, CA (United States); University of Southern California, Mork Family Department of Chemical Engineering and Materials Science, Los Angeles, CA (United States); Benjauthrit, Vatcharee; Zhou, Qifa; Shung, K.K. [University of Southern California, Department of Biomedical Engineering and NIH Transducer Resource Center, Los Angeles, CA (United States); Wei, Qiang; Huang, Yuhong [Chemat Technology Inc., Northridge, CA (United States)

    2013-05-15

    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 {mu}C/cm{sup 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. (orig.)

  1. NUTRIENTS CONCENTRATION AND RETRANSLOCATION IN THE Pinus taeda L. NEEDLES

    Directory of Open Access Journals (Sweden)

    Márcio Viera

    2010-03-01

    Full Text Available Aiming at evaluating nutrients concentration and retranslocation in the Pinus taeda L. needles, this study was developed in two stands, in native grass area and in second rotation area, with same species and same age (7.5 years old in Cambará do Sul, RS. The needles were collected in plants in four orthogonal points (South, North, East and West, sampled new needles, mature needles and old needles. The material was dried in a stove, milled and chemically analyzed (macro and micronutrients. The concentrations of N, P, K, B, Cu and Zn had decreased, of Ca, Fe and Mn increased, and the Mg and S have remained constant with the age of the needles. The retranslocation rate (old-new needles was more than 50% for most nutrients, except for Mn and Fe, showed that cumulative effect and the Ca reference element.

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

    Science.gov (United States)

    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.

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

    Directory of Open Access Journals (Sweden)

    Jaung-Geng Lin

    2013-01-01

    Full Text Available 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.

  4. Safety Issues for HIFU Transducer Design

    Science.gov (United States)

    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

  5. Dynamics of receptor and protein transducer homodimerisation

    Directory of Open Access Journals (Sweden)

    Kolch Walter

    2008-10-01

    Full Text Available Abstract Background Signalling pathways are complex systems in which not only simple monomeric molecules interact, but also more complex structures that include constitutive or induced protein assemblies. In particular, the hetero-and homo-dimerisation of proteins is a commonly encountered motif in signalling pathways. Several authors have suggested in recent times that dimerisation relates to a series of physical and biological outcomes used by the cell in the regulation of signal transduction. Results In this paper we investigate the role of homodimerisation in receptor-protein transducer interactions. Towards this end, mathematical modelling is used to analyse the features of such kind of interactions and to predict the behaviour of the system under different experimental conditions. A kinetic model in which the interaction between homodimers provokes a dual mechanism of activation (single and double protein transducer activation at the same time is proposed. In addition, we analyse under which conditions the use of a power-law representation for the system is useful. Furthermore, we investigate the dynamical consequences of this dual mechanism and compare the performance of the system in different simulated experimental conditions. Conclusion The analysis of our mathematical model suggests that in receptor-protein interacting systems with dual mechanism there may be a shift between double and single activation in a way that intense double protein transducer activation could initiate and dominate the signal in the short term (getting a fast intense signal, while single protein activation could control the system in the medium and long term (when input signal is weaker and decreases slowly. Our investigation suggests that homodimerisation and oligomerisation are mechanisms used to enhance and regulate the dynamic properties of the initial steps in signalling pathways.

  6. Transducer Arrays Suitable for Acoustic Imaging

    Science.gov (United States)

    1978-06-01

    effects of complex acoustic load and backing impedance on the overall response at the transducer can easily be taken tnto 16 account with this model. In...flat value of 3.56. t The cerasic msd epoxy plates were cleaaed in organic solvento , heated for sevfral hours to remove any absorbed solvents, and asse...and (3-49) we find that Z’fG dS+-if qy dS (3-51) 1 2 Z.i" Now the complex power flow i region I is P ’Q) ds’ 2 1 (3-52) C - 75- * From the continuity of

  7. A Hail Size Distribution Impact Transducer

    CERN Document Server

    Lane, John E; Haskell, William D; Cox, Robert B

    2014-01-01

    An active impact transducer has been designed and tested for the purpose of monitoring hail fall in the vicinity of the Space Shuttle launch pads. An important outcome of this design is the opportunity to utilize frequency analysis to discriminate between the audio signal generated from raindrop impacts and that of hailstone impacts. The sound of hail impacting a metal plate is sub-tly but distinctly different than the sound of rain impacts. This useful characteristic permits application of signal processing algorithms that are inherently more robust than techniques relying on amplitude processing alone in the implementation of a hail disdrometer.

  8. Paraesthesia during the needle-through-needle and the double segment technique for combined spinal epidural anaesthesia.

    Science.gov (United States)

    Ahn, H J; Choi, D H; Kim, C S

    2006-07-01

    Paraesthesia during regional anaesthesia is an unpleasant sensation for patients and, more importantly, in some cases it is related to neurological injury. Relatively few studies have been conducted on the frequency of paraesthesia during combined spinal epidural anaesthesia. We compared two combined spinal epidural anaesthesia techniques: the needle-through-needle technique and the double segment technique in this respect. We randomly allocated 116 parturients undergoing elective Caesarean section to receive anaesthesia using one of these techniques. Both techniques were performed using a 27G pencil point needle, an 18G Tuohy needle, and a 20G multiport epidural catheter from the same manufacturer. The overall frequency of paraesthesia was higher in the needle-through-needle technique group (56.9% vs. 31.6%, p = 0.011). The frequency of paraesthesia at spinal needle insertion was 20.7% in the needle-through-needle technique group and 8.8% in the double segment technique group; whereas the frequency of paraesthesia at epidural catheter insertion was 46.6% in the needle-through-needle technique group and 24.6% in the double segment technique group.

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

    Science.gov (United States)

    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.

  10. Percutaneous transhepatic cholangiography using special needle

    Energy Technology Data Exchange (ETDEWEB)

    Auh, Yong Ho [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1974-10-15

    Using the special needle (22 Gauze, 17 cm long, flexible needle) percutaneous transhepatic cholangiography were performed in 23 cases at Seoul National University Hospital during the period from July 1973 to August 1974. The results were as follows:1. Successful cholangiograms are obtained in 20 cases among the total of 23 cases. The 3 cases of the unsuccessful are two cases of sclerosing cholangitis and one case of hepatoma. 2. Average attempts of puncture in successful care are 3. It was not necessary to puncture more than 6 times to visualize biliary tree in dilated biliary tree. 3. Lateral approach (midaxillary line and 8th or 9th intercostal space) was used. The advantage of this method was briefly discussed. 4. Over all complication are occurred in 6 cases. 3 cases: transient fever 1 case: bile leakage without peritonitis 1 case: local peritonitis probably due to bile leakage 1 case: septicemia (the organism can not be detected even after blood culture)

  11. A retractable barb needle for drug darts

    Directory of Open Access Journals (Sweden)

    G.L. van Rooyen

    1973-07-01

    Full Text Available The mechanism and action of a new retractable barbneedle for drug darts are described. This dart needle is particularly successful in obviating unnecessary flight reactions andtrauma in darted animals, and facilitates the complete injection of the drug dose before the barb is retracted and the dart is dislogded from the animal. The whole process is completed within a few seconds and the expended dart can usually be retrieved in the immediate vicinity where the animal was darted.

  12. Extinction by the long dielectric needles

    CERN Document Server

    Cherkas, Nadejda L

    2016-01-01

    Electromagnetic wave extinction by the very long but finite dielectric needle is compared with that by the infinite dielectric cylinder for an oblique incidence of the electromagnetic wave. It is shown that the renormalized Hankel functions without the logarithmic terms should be used for the calculation of the extinction per unit length of the infinite dielectric cylinder to apply it for extinction calculations by the finite dielectric cylinder.

  13. Exploration of New Electroacupuncture Needle Material

    Directory of Open Access Journals (Sweden)

    Sanghun Lee

    2012-01-01

    Full Text Available Background. Electro Acupuncture (EA uses the acupuncture needle as an electrode to apply low-frequency stimulation. For its safe operation, it is essential to prevent any corrosion of the acupuncture needle. Objective. The aim of this study is to find an available material and determine the possibility of producing a standard EA needle that is biocompatible. Methods. Biocompatibility was tested by an MTT assay and cytotoxicity testing. Corrosion was observed with a scanning electron microscope (SEM after 0.5 mA, 60 min stimulation. The straightness was measured using a gap length of 100 mm, and tensile testing was performed by imposing a maximum tensile load. Results. Phosphor bronze, Ni coated SS304, were deemed inappropriate materials because of mild-to-moderate cytotoxicity and corrosion. Ti-6Al-4V and SS316 showed no cytotoxicity or corrosion. Ti-6Al-4V has a 70 times higher cost and 2.5 times lower conductivity than SS316. The results of both straightness and tensile testing confirmed that SS316 can be manufactured as a standard product. Conclusion. As a result, we confirmed that SS316 can be used a new EA electrode material. We hope that a further study of the maximum capacity of low-frequency stimulation using an SS316 for safe operation.

  14. Pulsed photoelectric field emission from needle cathodes

    CERN Document Server

    Hernandez-Garcia, C

    2002-01-01

    Experiments have been carried out to measure the current emitted by tungsten needles with 1-mu m tip radius operated up to 50 kV. This corresponds to electric fields in the order of 10 sup 9 to 10 sup 1 sup 0 V/m. The needles were illuminated with 10-ns laser pulses at 532, 355 and 266 nm. The laser intensity was varied from 10 sup 1 sup 0 to 10 sup 1 sup 2 W/m sup 2 , limited by damage to the needle tip. The observed quantum efficiency depends on the wavelength and the electric field, approaching unity at the highest electric fields when illuminated at 266 nm. Peak currents up to 100 mA were observed in nanosecond pulses, corresponding to an estimated brightness of 10 sup 1 sup 6 A/m sup 2 sr. Since the current is controlled by the laser intensity, with only a weak voltage dependence, these cathodes can be used for infrared and ultraviolet tabletop free-electron lasers and other applications that demand short electron-beam pulses with high brightness.

  15. Instantaneous crack detection using dual PZT transducers

    Science.gov (United States)

    Kim, Seung Bum; Sohn, Hoon

    2008-03-01

    A new guided wave based nondestructive testing (NDT) technique is developed to detect crack damage in metallic plates commonly used in aircraft without using prior baseline data or a predetermined decision boundary. In conventional guided wave based techniques, damage is often identified by comparing the "current" data obtained from a potentially damaged condition of a structure with the "past" baseline data collected at the pristine condition of the structure. However, it has been reported that this type of pattern comparison with the baseline data can lead to increased false alarms due to its susceptibility to varying operational and environmental conditions of the structure. In order to tackle this issue, a reference-free damage detection technique is previously developed using two pairs of collocated lead zirconate titanate transducers (PZTs) placed on both sides of a plate. In this study, this reference-free technique is further advanced so that the PZT transducers can be placed only on one side of the specimen. Crack formation creates Lamb wave mode conversion due to a sudden change in the thickness of the structure. Then, the proposed technique instantly detects the appearance of the crack by extracting this mode conversion from the measured Lamb waves. This study suggests a reference-free statistical approach that enables damage classification using only the current data set. Numerical and experimental results are presented to demonstrate the applicability of the proposed technique to instantaneous crack detection.

  16. Orbital Angular Momentum-Entanglement Frequency Transducer

    Science.gov (United States)

    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.

  17. Enhanced C-band Coaxial Orthomode Transducer

    Directory of Open Access Journals (Sweden)

    S. I. Piltyay

    2014-06-01

    Full Text Available Introduction. In this paper a novel configuration of wideband coherent coaxial OMT is presented. General Design of an Orthomode Transducer. The OMT consists of elements of 3 main types: a turnstile junction between coaxial quad-ridged waveguide and 4 coaxial transmission lines; 4 right-angle coaxial junctions for each polarization; 2 antiphase power combiners/dividers. A Turnstile Junction Optimization. The optimization of a turnstile junction has been performed. Its minimized reflection coefficient is less than −28 dB in the operation frequency band 3.4–5.4 GHz. An Optimized Right-Angle Coaxial Junction. A right-angle coaxial junction has been optimized to provide reflection coefficient, which is less than −42 dB in the operation frequency band 3.4–5.4 GHz. An Antiphase Power Combiner/Divider. The optimization of an antiphase power com-biner/divider has been performed. Its minimized reflection coefficient is less than −38 dB. Conclusions. A wideband coaxial orthomode transducer has been developed for the operation frequency band 3.4–5.4 GHz. In this frequency band the reflection coefficient is less than −27 dB.

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

    Science.gov (United States)

    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.

  19. Low-cost ultrasonic lamb-wave transducer

    Science.gov (United States)

    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.

  20. Piezoelectric single crystals for ultrasonic transducers in biomedical applications

    OpenAIRE

    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 LiNbO...

  1. Piezoelectric films for high frequency ultrasonic transducers in biomedical applications

    OpenAIRE

    Zhou, Qifa; Lau, Sienting; WU, DAWEI; Shung, K. Kirk

    2011-01-01

    Piezoelectric films have recently attracted considerable attention in the development of various sensor and actuator devices such as nonvolatile memories, tunable microwave circuits and ultrasound transducers. In this paper, an overview of the state of art in piezoelectric films for high frequency transducer applications is presented. Firstly, the basic principles of piezoelectric materials and design considerations for ultrasound transducers will be introduced. Following the review, the curr...

  2. Broadband tonpilz underwater acoustic transducers based on multimode optimization

    OpenAIRE

    Yao, Qingshan; Jensen, Leif Bjørnø

    1997-01-01

    Head flapping has often been considered to be deleterious for obtaining a tonpilz transducer with broadband, high power performance. In the present work, broadband, high power tonpilz transducers have been designed using the finite element (FE) method. Optimized vibrational modes including the flapping mode of the head are effectively used to achieve the broadband performance. The behavior of the transducer in its longitudinal piston mode and in its flapping mode is analysed for in-air and in...

  3. An Algorithm for Selecting Transducer Element Array Positions

    Science.gov (United States)

    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

  4. The effects of needle deformation during lumbar puncture

    Directory of Open Access Journals (Sweden)

    Hasan Hüseyin Özdemir

    2015-01-01

    Full Text Available Objective: The aim of this study is to assess deformation of the tip and deflection from the axis of 22-gauge Quincke needles when they are used for diagnostic lumbar puncture (LP. Thus, it can be determined whether constructional alterations of needles are important for predicting clinical problems after diagnostic LP. Materials and Methods: The 22-gauge Quincke needles used for diagnostic LP were evaluated. A specially designed protractor was used for measurement and evaluation. Waist circumference was measured in each patient. Patients were questioned about headaches occurring after LP. Results: A total of 115 Quincke-type spinal needles used in 113 patients were evaluated. No deflection was detected in 38 (33.1% of the needles. Deflection between 0.1° and 5° occurred in 43 (37.3% of the needles and deflection ≥ 5.1° occurred in 34 patients (29.6%. Forty-seven (41.5% patients experienced post lumbar puncture headache (PLPH and 13 (11.5% patients experienced intracranial hypotension (IH. No statistically significant correlation between the degree of deflection and headache was found (P > 0.05. Epidural blood patch was performed for three patients. Deformity in the form of bending like a hook occurred in seven needles and IH occurred in six patients using these needles. Two of the needles used in three patients requiring blood patch were found to be bent. Conclusion: Deformation of needles may increase complications after LP. Needle deformation may lead to IH. In case of deterioration in the structure of the needle, termination of the puncture procedure and the use of a new needle could reduce undesirable clinical consequences, especially IH.

  5. The effects of needle deformation during lumbar puncture

    Science.gov (United States)

    Özdemir, Hasan Hüseyin; Demir, Caner F.; Varol, Sefer; Arslan, Demet; Yıldız, Mustafa; Akil, Eşref

    2015-01-01

    Objective: The aim of this study is to assess deformation of the tip and deflection from the axis of 22-gauge Quincke needles when they are used for diagnostic lumbar puncture (LP). Thus, it can be determined whether constructional alterations of needles are important for predicting clinical problems after diagnostic LP. Materials and Methods: The 22-gauge Quincke needles used for diagnostic LP were evaluated. A specially designed protractor was used for measurement and evaluation. Waist circumference was measured in each patient. Patients were questioned about headaches occurring after LP. Results: A total of 115 Quincke-type spinal needles used in 113 patients were evaluated. No deflection was detected in 38 (33.1%) of the needles. Deflection between 0.1° and 5° occurred in 43 (37.3%) of the needles and deflection ≥ 5.1° occurred in 34 patients (29.6%). Forty-seven (41.5%) patients experienced post lumbar puncture headache (PLPH) and 13 (11.5%) patients experienced intracranial hypotension (IH). No statistically significant correlation between the degree of deflection and headache was found (P > 0.05). Epidural blood patch was performed for three patients. Deformity in the form of bending like a hook occurred in seven needles and IH occurred in six patients using these needles. Two of the needles used in three patients requiring blood patch were found to be bent. Conclusion: Deformation of needles may increase complications after LP. Needle deformation may lead to IH. In case of deterioration in the structure of the needle, termination of the puncture procedure and the use of a new needle could reduce undesirable clinical consequences, especially IH. PMID:25883480

  6. Monitoring Method for the Electrical Properties of Piezoelectric Transducer

    Institute of Scientific and Technical Information of China (English)

    李文; 朱泽琪

    2012-01-01

    The monitoring of cutting force in a vibration cutting process has a great significance in the popularization of ultrasonic vibration cutting technology. A new monitoring method of which the cutting force of ultrasonic elliptic vibration cutting is monitored using the electrical properties of transducer was proposed by studying on the relationship of cutting force, transducer electric impedance and load. A measurement system was designed for the electrical properties of transducer. The feasibility of cutting force monitoring method based on the electrical properties of piezoelectric transducer was proved by the cutting experiments.

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  9. 21 CFR 892.1570 - Diagnostic ultrasonic transducer.

    Science.gov (United States)

    2010-04-01

    ... that converts electrical signals into acoustic signals and acoustic signals into electrical signals and... include transmission media for acoustically coupling the transducer to the body surface, such as...

  10. Method and results of studying conduction measuring transducers

    Energy Technology Data Exchange (ETDEWEB)

    Dunaevskii, I.G.; Korotkov, B.N.; Povkh, I.L.; Cheplyukov, V.G.

    1977-01-01

    The method and results are given for determining the sensitivity of conduction measuring transducers with a local magnetic field. The results were obtained by frequency-dependent gradation on a model pulsation velocity gauge--a thermoanemometer. The effect of measuring a transducer's diameter, inter-electrode distance and nose line forms on its spatial resolution capacity was estimated. Adjustment functions were obtained for these transducers. A concept was formulated for measuring transducers belonging to the same class. 5 references, 5 figures.

  11. EFFICACY OF IMMUNOHISTOCHEMISTRY IN PROSTATE NEEDLE BIOPSIES

    Directory of Open Access Journals (Sweden)

    Tameem Afroz

    2016-10-01

    Full Text Available BACKGROUND Prostate needle biopsies can pose a major diagnostic challenge when it comes to differentiating adenocarcinoma and its variants from its benign mimics. In needle biopsies, when the suspicious focus is small, morphological features may not suffice to differentiate it from its morphologic mimics like atrophy, basal cell hyperplasia, reactive inflammatory changes, seminal vesicles and adenosis. Immunohistochemical marker for basal cells, p63 and prostate cancer specific marker, Alpha-Methylacyl-CoA Racemase (AMACR help in overcoming such diagnostic dilemmas. MATERIALS AND METHODS We analysed 157 prostate core needle biopsies over a period of 2 years. Routine Hematoxylin and Eosin (H and E sections and immunohistochemical markers for basal cells (p63 and prostate cancer specific marker (AMACR were used. Prospective study was done on prostate needle core biopsies. Biopsy was done under ultrasound guidance with an 18-gauge needle. Biopsy was done in patients with raised serum PSA levels for exclusion of prostate carcinoma. RESULTS Over a period of two years, 157 prostate core needle biopsies were studied. 83 were benign lesions comprising 69 benign prostatic hyperplasias, five basal cell hyperplasias, four granulomatous lesions and three showed atrophic changes. Two biopsies morphologically resembled seminal vesicles. Prostate cancer specific marker, AMACR was negative in all, but two lesions. In these two lesions, it showed weak nonspecific staining. Basal cell marker p63 showed a continuous staining pattern highlighting the basal cells in all the 69 cases of benign prostatic hyperplasia, 5 cases of basal hyperplasia showed positivity in all the hyperplastic basal cells. In the two cases of seminal vesicles, it showed intense basal cell positivity. It showed a discontinuous pattern in two of the four granulomatous lesions and showed a weak, but a continuous staining pattern in the atrophic lesions. 74 were adenocarcinomas; the predominant

  12. The Cavitation With Plate Transducer And Non Cavitation With Knob Transducer By Manihot Utilissima Fermentation The Potential Hydrogen Ph Method

    Directory of Open Access Journals (Sweden)

    Syamsul Arifin

    2015-08-01

    Full Text Available Abstract Manihot M. utilissima fermentation is popular foods and drinks for Indonesia people but it fermented foods 24 hours per day will breed fungi and anaerobic bacteriae so it will make it into acidic foods and alcoholic beverages. Ultrasonic 48 kHz 5 Vpp 1 VDC with functional generator and of the two models of transducers will have two different phenomena on M. utilissima fermentation. Methods Model-1. Radiation ultrasonic transducer plate or Flat of piezoelectric speakers2 were applied with transducers M. utilissima dipped in a test tube. Model-2. Knob or small ball ultrasonic transducer 12 balls were applied with transducers of tin knob which was connected to the copper wire2 and piezoelectricspeakers were dipped into the media M. utilissima in a test tube. After ultrasonic radiation fluid liquid from two models of transducers measured total acid in M. utilissima fermentation liquid by paper indicators of potential Hydrogen pH. The conclusion of this study can predict different phenomena namely the transducer plate of the initial pH value-acid fermentation M. utilissima can change increases the pH-value end of the base which means that the transducer plate has a cavitation phenomenon and media M. utilissima lead to the delicious food but on transducer knob that the initial pH value-acid fermentation M. utilissima will decrease more acid value so that have no phenomenon of cavitation and the media will lead M. utilissima to be alcoholic foods.

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

    OpenAIRE

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

    2016-01-01

    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 th...

  14. Linear ultrasonic motor using quadrate plate transducer

    Institute of Scientific and Technical Information of China (English)

    Jiamei JIN; Chunsheng ZHAO

    2009-01-01

    A linear ultrasonic motor using a quadrate plate transducer was developed for precision positioning. This motor consists of two pairs of Pb(Zr, Ti)O3 piezo-electric ceramic elements, which are piezoelectrically excited into the second-bending mode of the motor stator's neutral surface in two orthogonal directions, on which the tops of four projections move along an elliptical trajectory, which in turn drives a contacted slider into linear motion via frictional forces. The coincident frequency of the stator is easily obtained for its coincident characteristic dimen-sion in two orthogonal directions. The performance characteristics achieved by the motor are: 1) a maximum linear speed of more than 60 mm/s; 2) a stroke of more than 150 mm; 3) a driving force of more than 5.0 N; and 4) a response time of about 2 ms.

  15. Serrated needle design facilitates precise round window membrane perforation.

    Science.gov (United States)

    Stevens, James P; Watanabe, Hirobumi; Kysar, Jeffrey W; Lalwani, Anil K

    2016-07-01

    The round window membrane (RWM) has become the preferred route, over cochleostomy, for the introduction of cochlear implant electrodes as it minimizes inner ear trauma. However, in the absence of a tool designed for creating precise perforation, current practices lead to tearing of the RWM and significant intracochlear pressure fluctuations. On the basis of RWM mechanical properties, we have designed a multi-serrated needle to create consistent holes without membrane tearing or damaging inner ear structures. Four and eight-serrated needles were designed and produced with wire electrical discharge machining (EDM). The needle's ability to create RWM perforations was tested in deidentified, commercially acquired temporal bones with the assistance of a micromanipulator. Subsequently, specimens were imaged under light and scanning electron microscopy (SEM). The needles created consistent, appropriately sized holes in the membrane with minimal tearing. While a four-serrated crown needle made rectangular/trapezoid perforations, the octagonal crown formed smooth oval holes within the membrane. Though designed for single use, the needle tolerated repeated use without significant damage. The serrated needles formed precise perforations in the RWM while minimizing damage during cochlear implantation. The octagonal needle design created the preferred oval perforation better than the quad needle. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 104A: 1633-1637, 2016.

  16. Lab in a needle for epidural space identification

    Science.gov (United States)

    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.

  17. Transverse Oscillation Vector Velocity Estimation using a Phased Array Transducer

    DEFF Research Database (Denmark)

    Marcher, Jønne; Pihl, Michael Johannes; Seerup, Gert

    2012-01-01

    The Transverse Oscillation method has shown its commercial feasibility, providing the user with 2D velocity information. Todays implementation on commercial ultrasound platforms only support linear array transducers and are limited in depth. Extending the implementation to a phased array transducer...

  18. Metal cap flexural transducers for air-coupled ultrasonics

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  20. A Force Transducer from a Junk Electronic Balance

    Science.gov (United States)

    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…

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

    Science.gov (United States)

    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,…

  2. Resonant acoustic transducer system for a well drilling string

    Science.gov (United States)

    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.

  3. Energy Conversion Efficiency of Rainbow Shape Piezoelectric Transducer

    Institute of Scientific and Technical Information of China (English)

    LIU Xiangjian; CHEN Renwen; ZHU Liya

    2012-01-01

    With the aim to enhance the energy conversion efficiency of the rainbow shape piezoelectric transducer,an analysis model of energy conversion efficiency is established based on the elastic mechanics theory and piezoelectricity theory.It can be found that the energy conversion efficiency of the rainbow shape piezoelectric transducer mainly depends on its shape parameters and material properties from the analysis model.Simulation results show that there is an optimal length ratio to generate maximum energy conversion efficiency and the optimal length ratios and energy conversion efficiencies of beryllium bronze substrate transducer and steel substrate transducer are (0.65,2.21%) and (0.65,1.64%) respectively.The optimal thickness ratios and energy conversion efficiencies of beryllium bronze substrate transducer and steel substrate transducer are (1.16,2.56%) and (1.49,1.57%) respectively.With the increase of width ratio and initial curvature radius,both the energy conversion efficiencies decrease.Moreover,beryllium bronze flexible substrate transducer is superior to the steel flexible substrate transducer.

  4. Micro-stereolithography as a transducer design method.

    Science.gov (United States)

    Ho, K S; Bradley, R J; Billson, D R; Hutchins, D A

    2008-03-01

    This paper investigates the use of micro-stereolithography, a rapid prototyping technique, in the manufacture of transducers. It is illustrated for the production of electromagnetic acoustic transducer (EMATs) coils in both meander-line and spiral configurations. A synthetic aperture focussing technique (SAFT) has been applied to the ultrasonic signals from these devices to reconstruct images in metallic objects.

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

    Directory of Open Access Journals (Sweden)

    Mohammad Saleh Salmanpour

    2016-12-01

    Full Text Available 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.

  6. Calibration of Field II using a Convex Ultrasound Transducer

    DEFF Research Database (Denmark)

    Bæk, David; Jensen, Jørgen Arendt; Willatzen, Morten

    2010-01-01

    Field II is an ultrasound simulation program capable of simulating the pressure scattering from inhomogeneous tissue. The simulations are based on a convolution between spatial impulse responses from the field in front of the transducer and the volt-to-surface acceleration impulse response...... of the transducer. For such simulations to reflect actual measured intensities and pressure levels, the transducer impulse response is to be known. This work presents the results of combining a modified form of a 1D linear transducer model originally suggested by Willatzen with the Field II program to calibrate...... BK-Medical (Herlev, Denmark). As input waveform for the Field model we measured the output voltage of the research amplifier, which peak voltage was limited to 31 V to avoid too high non linear effects. We measured the hydrophone output from three transducer front elements by averaging 40 shoot...

  7. Transducers for Sound and Vibration - FEM Based Design

    DEFF Research Database (Denmark)

    Liu, Bin

    2001-01-01

    Design of transducers for measurement of vibration (piezoelectric accelerometers) and sound (condenser microphones) is a very labour intensive work. The design work is mostly based on experience and on simple analogies to electrical circuit design. Often a time consuming itterative loop is used......: Specification of the transducer, production of a physical prototype, measurements on the prototype, changed specification of the transducer etc. Furthermore are many transducers made based on customer requirements which also increases the amount of required design work. For these reasons there is a need...... for methods that can reduce the design time consumption and the number of itterations. The present work proposes to use finite element based programs for simulating the behaviour of a transducer with a given set of specifications. A simulation program for accelerometers was developed and has been tested...

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

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

    Science.gov (United States)

    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

  11. Dynamics of electromagnetically-transduced microresonators

    Science.gov (United States)

    Sabater, Andrew B.

    Electromagnetic transduction is a means of actuating and sensing microelectromechanical systems (MEMS) through the interaction of electric and magnetic fields. Electromagnetically-transduced devices are Lorentz force actuated and sensed via an induced electromotive force (EMF). As such, transduction requires that the vibrations of one of these devices take place within a magnetic field. Provided one can leverage relatively recent advances with rare-earth magnets or complementary metal-oxide-semiconductor (CMOS) fabrication for magnetic field generation, electromagnetic transduction offers many distinct advantages over other methods of actuating and sensing MEMS. These advantages include the ability to generate large forces and moments that are linearly related to the supplied current, comparatively low power consumption metrics obtained with comparatively-low excitation voltages, and comparatively-simple device geometries that do not interfere with transduction. This type of transduction also facilitates operation in fluidic or harsh environments. In addition, an electromagnetically-transduced microresonator (ETM) could be used in the future for numerous applications which utilize a microresonator, such as electrical signal processing and resonant-based mass sensing, as well as self-sustaining oscillators. Other potential applications that are relatively unique to ETMs are a product of electromagnetic transduction, like magnetic field sensing. Arrays of electromagnetically-transduced devices could also be used to improve a sensor's throughput, or the total amount of sensed information, as it is comparatively-easy to electrically-couple multiple devices together. The efforts associated with the design, fabrication and characterization in both low-pressure and atmospheric conditions of one such array that has multiple, easily-tailored resonances with single-input, single-output (SISO) characteristics are documented in this dissertation. This type of electromagnetic

  12. Needle Steering in 3-D Via Rapid Replanning

    Science.gov (United States)

    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

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

    NARCIS (Netherlands)

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

    2017-01-01

    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 s

  14. Path planning for steerable needles using duty-cycled spinning

    Directory of Open Access Journals (Sweden)

    Borges G.A.

    2011-12-01

    Full Text Available This paper presents an adaptive approach for 2D path planning of steerable needles. It combines dutycycled rotation of the needle with the classic RapidlyExploring Random Tree (RRT algorithm and it is used intraoperatively to compensate for system uncertainties and perturbations. Simulation results demonstrate the performance of the proposed motion planner on a workspace based in ultrasound images.

  15. Observations on rotating needle insertions using a brachytherapy robot

    Energy Technology Data Exchange (ETDEWEB)

    Meltsner, M A [Department of Medical Physics, University of Wisconsin, Madison, WI 53706 (United States); Ferrier, N J [Department of Mechanical Engineering, University of Wisconsin, Madison, WI 53706 (United States); Thomadsen, B R [Department of Medical Physics, University of Wisconsin, Madison, WI 53706 (United States)

    2007-09-21

    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.

  16. Synthesis of nano-crystalline multifibrous zirconia needle

    Energy Technology Data Exchange (ETDEWEB)

    Biswas, Mridula; Bandyopadhyay, Siddhartha, E-mail: sbando@cgcri.res.in

    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.

  17. Needle Steering in 3-D Via Rapid Replanning.

    Science.gov (United States)

    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.

  18. TRANSDUCER GENERATED ARRAYS OF ROBOTIC NANO-ARMS.

    Science.gov (United States)

    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.

  19. Design of advanced ultrasonic transducers for welding devices.

    Science.gov (United States)

    Parrini, L

    2001-11-01

    A new high frequency ultrasonic transducer has been conceived, designed, prototyped, and tested. In the design phase, an advanced approach was used and established. The method is based on an initial design estimate obtained with finite element method (FEM) simulations. The simulated ultrasonic transducers and resonators are then built and characterized experimentally through laser interferometry and electrical resonance spectra. The comparison of simulation results with experimental data allows the parameters of FEM models to be adjusted and optimized. The achieved FEM simulations exhibit a remarkably high predictive potential and allow full control of the vibration behavior of the transducer. The new transducer is mounted on a wire bonder with a flange whose special geometry was calculated by means of FEM simulations. This flange allows the transducer to be attached on the wire bonder, not only in longitudinal nodes, but also in radial nodes of the ultrasonic field excited in the horn. This leads to a total decoupling of the transducer to the wire bonder, which has not been achieved so far. The new approach to mount ultrasonic transducers on a welding device is of major importance, not only for wire bonding, but also for all high power ultrasound applications and has been patented.

  20. Design of an Optically Controlled MR-Compatible Active Needle

    Science.gov (United States)

    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

  1. Removal of an embedded crochet needle in the mouth.

    Science.gov (United States)

    Klovenski, Victoria; Juergens, Andrew; Lappo, Kyla; Marshall, Kyle

    2016-01-01

    A 3-year-old child presented to the emergency department with a crochet needle lodged in her posterior oral cavity. To localize the needle and significant surrounding anatomic structures, bedside transcavitary ultrasound was employed. After careful localization, the needle was removed using a modified needle cover technique. A review of barbed foreign object removal techniques, including advance-and-cut, retrograde, string-yank, and needle cover techniques, is presented. Important considerations while planning any procedure include risk, benefit, availability of staff, and availability of equipment. Proper anesthesia is paramount to the success of these procedures, and sedation in pediatric patients may prove necessary. Postprocedure wound care and follow-up must also be arranged. This case demonstrates the importance of adaptation of well-documented techniques to remain flexible for any situation that may present to the emergency department.

  2. A novel accurate minioptical tracking system for percutaneous needle placement.

    Science.gov (United States)

    von Jako, Christopher R; Zuk, Yuval; Zur, Oded; Gilboa, Pini

    2013-08-01

    The novel optical tracking system employs a miniature video camera, mounted on the hub of an interventional needle, to determine the location and orientation of the needle relative to a skin-attached sticker with color reference markers. A computed tomography (CT) scan is used to register the same reference markers to the anatomy in the CT images, and thus, register the needle to the anatomy and to a user-selected target. A computer displays a simulation of the interventional needle on the CT images, providing guidance information to assist a user in directing the needle to the target. Bench testing was performed on a custom phantom to determine the accuracy of this minioptical tracking system. The resulting accuracy data demonstrate a good correlation with phantom coordinates and the CT images.

  3. Effect of physical disturbance on the structure of needle coke

    Science.gov (United States)

    Zhao, Shi-Gui; Wang, Bao-Cheng; Sun, Quan

    2010-10-01

    Through different preparation technology, this paper reports that the needle coke is prepared with coal-tar pitch under the effect of magnetic field and ultrasonic cavitation. It studies the effect of physical disturbance on the structure of needle coke. The structure of needle coke is characterized by scanning electron microscope and x-ray diffractometer, and the influence mechanism is analysed. Results showed that the structure and property of needle coke could be effectively improved by magnetic field and ultrasonic cavitations, such as degree of order, degree of graphitization and crystallization. Comparatively speaking, the effect of magnetic field was greater. The graphitization degree of needle coke prepared under the effect of magnetic field is up to 45.35%.

  4. Bonding and impedance matching of acoustic transducers using silver epoxy.

    Science.gov (United States)

    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.

  5. Design, analysis, and modeling of giant magnetostrictive transducers

    Science.gov (United States)

    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

  6. Dynamic mechanism and its modelling of micromachined electrostatic ultrasonic transducers

    Institute of Scientific and Technical Information of China (English)

    葛立峰

    1999-01-01

    A tensile-plate-on-air-spring model (or called TDK model for short) for micromachined electrostatic ultrasonic transducers has been developed based on a thorough investigation of their dynamic mechanism. The mechanical stiffness effects caused by the compressibility of air gaps, bending stiffness of the diaphragm and in-plane tension applied to the diaphragm, together with an electrostatic negative stiffness effect are included completely in the model. Desired particular fundamental frequency and bandwidth can be obtained by only properly tailoring the geometry, dimensions and materials of transducers according to the model, which provides thereby a reliable theoretical basis for the understanding and optimised design of such transducers.

  7. Inter Digital Transducer Modelling through Mason Equivalent Circuit Model

    DEFF Research Database (Denmark)

    Mishra, Dipti; Singh, Abhishek; Hussain, Dil muhammed Akbar

    2016-01-01

    The frequency reliance of inter-digital transducer is analyzed with the help of MASON’s Equivalent circuit which is based on Smith’s Equivalent circuit which is further based on Foster’sNetwork. An inter-digital transducer has been demonstratedas a RLC network. The circuit is simulated...... by Simulation program with Integrated Circuit Emphasis (HSPICE), a well-liked electronic path simulator. The acoustic wave devices are not suitable to simulation through circuit simulator.In this paper, an electrical model of Mason’s Equivalent electricalcircuit for an inter-digital transducer (IDT...

  8. Inter digital transducer modelling through Mason equivalent circuit model

    DEFF Research Database (Denmark)

    Mishra, Dipti; Singh, Abhishek; Hussain, Dil muhammed Akbar

    2016-01-01

    The frequency reliance of inter-digital transducer is analyzed with the help of MASON's Equivalent circuit which is based on Smith's Equivalent circuit which is further based on Foster's Network. An inter-digital transducer has been demonstrated as a RLC network. The circuit is simulated...... by Simulation program with Integrated Circuit Emphasis (HSPICE), a well-liked electronic path simulator. The acoustic wave devices are not suitable to simulation through circuit simulator. In this paper, an electrical model of Mason's Equivalent electrical circuit for an inter-digital transducer (IDT...

  9. Ultrasonic Transducer Peak-to-Peak Optical Measurement

    Directory of Open Access Journals (Sweden)

    Pavel Skarvada

    2012-01-01

    Full Text Available Possible optical setups for measurement of the peak-to-peak value of an ultrasonic transducer are described in this work. The Michelson interferometer with the calibrated nanopositioner in reference path and laser Doppler vibrometer were used for the basic measurement of vibration displacement. Langevin type of ultrasonic transducer is used for the purposes of Electro-Ultrasonic Nonlinear Spectroscopy (EUNS. Parameters of produced mechanical vibration have to been well known for EUNS. Moreover, a monitoring of mechanical vibration frequency shift with a mass load and sample-transducer coupling is important for EUNS measurement.

  10. Broadband electrical impedance matching for piezoelectric ultrasound transducers.

    Science.gov (United States)

    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.

  11. USE OF PELTIER COOLERS AS SOIL HEAT FLUX TRANSDUCERS.

    Science.gov (United States)

    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.

  12. A thermal insulation method for a piezoelectric transducer

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    This study deals with the sources of signal distortion of a piezoelectric transducer heated by measured gas flow. These signal distortions originate from both unloading of preload on a piezocrystal because of expansion of a diaphragm in the test apparatus and the pyroelectric effect of a heated piezoelectric crystal. A plastic film on the diaphragm of the transducer can effectively insulate the diaphragm and the piezocrystal within transducer from heating by gas flow, eliminating the sources of distortion. A method for evaluating the thickness of the film is proposed.

  13. Broadband tonpilz underwater acoustic transducers based on multimode optimization

    DEFF Research Database (Denmark)

    Yao, Qingshan; Jensen, Leif Bjørnø

    1997-01-01

    Head flapping has often been considered to be deleterious for obtaining a tonpilz transducer with broadband, high power performance. In the present work, broadband, high power tonpilz transducers have been designed using the finite element (FE) method. Optimized vibrational modes including...... the flapping mode of the head are effectively used to achieve the broadband performance. The behavior of the transducer in its longitudinal piston mode and in its flapping mode is analysed for in-air and in-water situations. For the 37.8% bandwidth of the center frequency from 28.5 to 41.8 kHz, the amplitude...

  14. Design and fabrication of a low frequency giant magnetostrictive transducer

    Energy Technology Data Exchange (ETDEWEB)

    Dhilsha, K.R. [Nat. Inst. of Ocean Technol, Madras (India); Markandeyulu, G.; Subrahmanyeswara Rao, B.V.P.; Rama Rao, K.V.S. [Magnetism and Magnetic Materials Laboratory, Department of Physics, Indian Institute of Technology, Madras 600 036 (India)

    1997-08-01

    A Tonpilz-type single ended transducer employing two rods of giant magnetostrictive materials has been fabricated and its underwater acoustic characteristics have been studied. The transducer resonated at a frequency of 3.1 kHz in air and at 2.65 kHz in water with a Q factor of 6. The TCR and RS at resonance in water have been measured to be 172.1 dB re 1 {mu}Pa/A at 1 m and -196.7 dB re 1 V/{mu}Pa respectively. The dimensions of the transducer are 60 mm in diameter and 110 mm long. (orig.)

  15. Optimization of ultrasonic transducers for selective guided wave actuation

    Science.gov (United States)

    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.

  16. [Acupuncture therapy for regaining consciousness in terms of acupoint location, needle insertion and needle manipulation].

    Science.gov (United States)

    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.

  17. [Design of acupoint electric characteristic sensing needle].

    Science.gov (United States)

    Liu, Tang-yi; Yang, Hua-yuan; Kuai, Le; Gao, Ming

    2007-09-01

    The electric characteristics of acupoints have been confirmed by researchers at home and abroad. Because the traditional detection methods are various (mainly are different positions of the reference electrode), and they are influenced by many affective factors, with unstable results and bad repeatability, so the studies of the electric characteristics of acupoints are limited. The acupoint electric characteristic sensing needle is introduced in detail from its design, detection methods and so on, which can detects changes of the acupoint electric characteristics of channels and acupoints in different healthy states real-timely, dynamically and continuously. It not only can avoid those affective factors, and also the detective results are relatively stable and the repeatability is also better.

  18. Fine-needle aspiration cytology in fibromatoses.

    Science.gov (United States)

    Zaharopoulos, P; Wong, J Y

    1992-01-01

    Fine-needle aspiration (FNA) cytology was performed in seven cases of fibromatosis of variable types with tumorous clinical presentation. These included: four cases of musculoaponeurotic fibromatosis, two in posterior neck muscles, one in anterior neck muscles and one in intercostal muscles; one case of fibromatosis of the breast; and two cases of fibromatosis colli in neonates. In all cases the specimens contained connective tissue with many fibroblast-like cells, lacking features which could indicate a malignant lesion. The findings in these cases indicate that, although by FNA cytology in fibromatoses a specific diagnosis for each pathologic entity may not be easily reached, in the proper clinical setting the cytologic findings can be of sufficient relevance to offset the need for an open tissue biopsy, where there are valid reasons against a surgical intervention.

  19. Emergency percutaneous needle decompression for tension pneumoperitoneum

    Directory of Open Access Journals (Sweden)

    Körner Markus

    2011-05-01

    Full Text Available Abstract Background Tension pneumoperitoneum as a complication of iatrogenic bowel perforation during endoscopy is a dramatic condition in which intraperitoneal air under pressure causes hemodynamic and ventilatory compromise. Like tension pneumothorax, urgent intervention is required. Immediate surgical decompression though is not always possible due to the limitations of the preclinical management and sometimes to capacity constraints of medical staff and equipment in the clinic. Methods This is a retrospective analysis of cases of pneumoperitoneum and tension pneumoperitoneum due to iatrogenic bowel perforation. All patients admitted to our surgical department between January 2005 and October 2010 were included. Tension pneumoperitoneum was diagnosed in those patients presenting signs of hemodynamic and ventilatory compromise in addition to abdominal distension. Results Between January 2005 and October 2010 eleven patients with iatrogenic bowel perforation were admitted to our surgical department. The mean time between perforation and admission was 36 ± 14 hrs (range 30 min - 130 hrs, between ER admission and begin of the operation 3 hrs and 15 min ± 47 min (range 60 min - 9 hrs. Three out of eleven patients had clinical signs of tension pneumoperitoneum. In those patients emergency percutaneous needle decompression was performed with a 16G venous catheter. This improved significantly the patients' condition (stabilization of vital signs, reducing jugular vein congestion, bridging the time to the start of the operation. Conclusions Hemodynamical and respiratory compromise in addition to abdominal distension shortly after endoscopy are strongly suggestive of tension pneumoperitoneum due to iatrogenic bowel perforation. This is a rare but life threatening condition and it can be managed in a preclinical and clinical setting with emergency percutaneous needle decompression like tension pneumothorax. Emergency percutaneous decompression is no

  20. Remote Electromagnetic Vibration of Steerable Needles for Imaging in Power Doppler Ultrasound.

    Science.gov (United States)

    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.

  1. Skin Blood Perfusion and Cellular Response to Insertion of Insulin Pen Needles With Different Diameters

    DEFF Research Database (Denmark)

    Præstmark, Kezia Ann; Stallknecht, Bente Merete; Bo Jensen, Casper;

    2014-01-01

    Today most research on pen needle design revolves around pain perception statements through clinical trials, but these are both costly, timely, and require high sample sizes. The purpose of this study was to test if tissue damage, caused by different types of needles, can be assessed by evaluating...... skin blood perfusion response around needle insertion sites. Three common sized pen needles of 28G, 30G, and 32G as well as hooked 32G needles, were inserted into the neck skin of pigs and then removed. Laser Speckle Contrast Analysis was used to measure skin blood perfusion for 20 minutes after......, but there was a trend of an increased response with increasing needle diameter. Skin blood perfusion response to pen needle insertions rank according to needle diameter, and the tissue response caused by hooked 32G needles corresponds to that of 28G needles. The relation between needle diameter and trauma when...

  2. Electromechanically active polymer transducers: research in Europe

    Science.gov (United States)

    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

  3. Needle steering for robot-assisted insertion into soft tissue: A survey

    Science.gov (United States)

    Gao, Dedong; Lei, Yong; Zheng, Haojun

    2012-07-01

    Needle insertion is a common surgical procedure used in diagnosis and treatment. The needle steering technologies make continuous developments in theoretical and practical aspects along with the in-depth research on needle insertion. It is necessary to summarize and analyze the existing results to promote the future development of theories and applications of needle insertion. Thus, a survey of the state of the art of research is presented on algorithms of needle steering techniques, the surgical robots and devices. Based on the analysis of the needle insertion procedure, the concept of needle steering is defined as a kinematics problem, which is to place the needle at the target and avoid the obstacles. The needle steering techniques, including the artificial potential field method and the nonholonomic model, are introduced to control the needles for improving the accuracy. Based on the quasi-static thinking, the virtual spring model and the cantilever-beam model are developed to calculate the amount of needle deflection and generate the needle path. The phantoms instead of the real tissue are used to verify the models mentioned in most of the experimentations. For the desired needle trajectories, the image-guided robotic devices and some novel needles are presented to achieve the needle steering. Finally, the challenges are provided involving the controllability of the long flexible needle and the properties of soft tissue. The results and investigations can be used for further study on the precision and accuracy of needle insertion.

  4. Integration of Capacitive Micromachined Ultrasound Transducers to Microfluidic Devices

    KAUST Repository

    Viržonis, Darius

    2013-10-22

    The design and manufacturing flexibility of capacitive micromachined ultrasound transducers (CMUT) makes them attractive option for integration with microfluidic devices both for sensing and fluid manipulation. CMUT concept is introduced here by presentin

  5. Lithium niobate ultrasonic transducer design for Enhanced Oil Recovery.

    Science.gov (United States)

    Wang, Zhenjun; Xu, Yuanming; Gu, Yuting

    2015-11-01

    Due to the strong piezoelectric effect possessed by lithium niobate, a new idea that uses lithium niobate to design high-power ultrasonic transducer for Enhanced Oil Recovery technology is proposed. The purpose of this paper is to lay the foundation for the further research and development of high-power ultrasonic oil production technique. The main contents of this paper are as follows: firstly, structure design technique and application of a new high-power ultrasonic transducer are introduced; secondly, the experiment for reducing the viscosity of super heavy oil by this transducer is done, the optimum ultrasonic parameters for reducing the viscosity of super heavy oil are given. Experimental results show that heavy large molecules in super heavy oil can be cracked into light hydrocarbon substances under strong cavitation effect caused by high-intensity ultrasonic wave. Experiment proves that it is indeed feasible to design high-power ultrasonic transducer for ultrasonic oil production technology using lithium niobate.

  6. Performance Evaluation of Pressure Transducers for Water Impacts

    Science.gov (United States)

    Vassilakos, Gregory J.; Stegall, David E.; Treadway, Sean

    2012-01-01

    The Orion Multi-Purpose Crew Vehicle is being designed for water landings. In order to benchmark the ability of engineering tools to predict water landing loads, test programs are underway for scale model and full-scale water impacts. These test programs are predicated on the reliable measurement of impact pressure histories. Tests have been performed with a variety of pressure transducers from various manufacturers. Both piezoelectric and piezoresistive devices have been tested. Effects such as thermal shock, pinching of the transducer head, and flushness of the transducer mounting have been studied. Data acquisition issues such as sampling rate and anti-aliasing filtering also have been studied. The response of pressure transducers have been compared side-by-side on an impulse test rig and on a 20-inch diameter hemisphere dropped into a pool of water. The results have identified a range of viable configurations for pressure measurement dependent on the objectives of the test program.

  7. Transducer for Tension Force Measuring of Strip Materials

    Directory of Open Access Journals (Sweden)

    Emad S. Addasi

    2005-01-01

    Full Text Available In winding-up motor drive systems, such as that used in textile industry, it is very important to get a constant tension force for the winding strip material (thread and to reduce its oscillations. This study recommends a transducer with a special design to be used in the mentioned motor drive systems. By using a piston damper, spring, levers, slider and other simple components the suggested sensor (transducer can be used to control the motor speed for getting the required thread tension force. Also the suggested transducer avoids the disadvantage of other used conventional transducer: the parasitic (detrimental oscillations of the thread tension force, which affect the quality of the produced strip material.

  8. Photoacoustic tomography of monkey brain using virtual point ultrasonic transducers.

    Science.gov (United States)

    Nie, Liming; Guo, Zijian; Wang, Lihong V

    2011-07-01

    A photoacoustic tomography system (PAT) using virtual point ultrasonic transducers was developed and applied to image a monkey brain. The custom-built transducers provide a 10-fold greater field-of-view (FOV) than finite-aperture unfocused transducers as well as an improved signal-to-noise ratio (SNR) and reduced artifacts rather than negative-lens transducers. Their tangential resolution, radial resolution, and (SNR) improvements were quantified using tissue phantoms. Our PAT system can achieve high uniformity in both resolution (8) within a large FOV of 6 cm in diameter, even when the imaging objects are enclosed by a monkey skull. The cerebral cortex of a monkey brain was accurately mapped transcranially, through a skull ranging from 2 to 4 mm in thickness. This study demonstrates that PAT can overcome the optical and ultrasound attenuation of a relatively thick skull and can potentially be applied to human neonatal brain imaging.

  9. Traceable dynamic calibration of force transducers by primary means

    Science.gov (United States)

    Vlajic, Nicholas; Chijioke, Ako

    2016-08-01

    We describe an apparatus for traceable, dynamic calibration of force transducers using harmonic excitation, and report calibration measurements of force transducers using this apparatus. In this system, the force applied to the transducer is produced by the acceleration of an attached mass, and is determined according to Newton’s second law, F  =  ma. The acceleration is measured by primary means, using laser interferometry. The capabilities of this system are demonstrated by performing dynamic calibrations of two shear-web-type force transducers up to a frequency of 2 kHz, with an expanded uncertainty below 1.2%. We give an account of all significant sources of uncertainty, including a detailed consideration of the effects of dynamic tilting (rocking), which is a leading source of uncertainty in such harmonic force calibration systems.

  10. Finite element analysis for acoustic characteristics of a magnetostrictive transducer

    Science.gov (United States)

    Kim, Jaehwan; Jung, Eunmi

    2005-12-01

    This paper presents a finite element analysis for a magnetostrictive transducer by taking into account the nonlinear behavior of the magnetostrictive material and fluid interaction. A finite element formulation is derived for the coupling of magnetostrictive and elastic materials based upon a separated magnetic and displacement field calculation and a curve fitting technique of material properties. The fluid and structure coupled problem is taken into account based upon pressure and velocity potential fields formulation. Infinite wave envelope elements are introduced at an artificial boundary to deal with the infinite fluid domain. A finite element code for the analysis of a magnetostrictive transducer is developed. A magnetostrictive tonpilz transducer is taken as an example and verification for the developed program is made by comparing with a commercial code. The acoustic characteristics of the magnetostrictive tonpilz transducer are calculated in terms of radiation pattern and transmitted current response.

  11. Spatial impulse response of a rectangular double curved transducer

    DEFF Research Database (Denmark)

    Bæk, David; Jensen, Jørgen Arendt; Willatzen, Morten

    2012-01-01

    Calculation of the pressure field from transducers having both a convex and a concave surface geometry is a complicated assignment that often is accomplished by subdividing the transducer surface into smaller flat elements of which the spatial impulse response is known. This method is often seen...... applied to curved transducers because an analytical solution is un-known. In this work a semi-analytical algorithm for the exact solution to a first order in diffraction effect of the spatial impulse response of rectangular shaped double curved transducers is presented. The algorithm and an approximation...... approximations ranging from 0.03 % to 0.8 % relative to a numerical solution for the spatial impulse response. It is shown that the presented algorithm gives consistent results with Field II for a linear flat, a linear focused, and a convex non-focused element. Best solution was found to be 0.01 % with a three...

  12. Wideband Single Crystal Transducer for Bone Characterization Project

    Data.gov (United States)

    National Aeronautics and Space Administration — TRS proposes to develop a simple-to-use, launch capable, ultrasound transducer that is capable of producing the necessary bandwidth to accurately determine in vivo...

  13. Comparison of a needle-free high-pressure injection system with needle-tipped injection of intracavernosal alprostadil for erectile dysfunction.

    Science.gov (United States)

    Harding, L M; Adeniyi, A; Everson, R; Barker, S; Ralph, D J; Baranowski, A P

    2002-12-01

    Patients identified from hospital records as using alprostadil injections for erectile dysfunction were invited to take part in this open crossover study. On alternate weeks eight patients were given intracavernosal needle injections and transdermal needle-free injection of alprostadil in a randomized order. Efficacy of injection and associated pain were assessed and compared for the two methods. Pain produced during injection was significantly greater with the needle-free system than with the needle-tipped injection whilst efficacy was significantly less. Bruising was reported in all except one patient following needle-free injection only. Patient ratings of the needle-free injector were significantly lower than ratings for needle-tipped alprostadil delivery and when asked to express a preference, every patient chose the needle-tipped injection over the needle-free device.

  14. Development of plasma needle to be used for biomedical applications

    Science.gov (United States)

    Bora, B.; Jain, J.; Inestrosa-Izurieta, M. J.; Avaria, G.; Moreno, J.; Pavez, C.; Marcelain, K.; Armisen, R.; Soto, L.

    2016-05-01

    Plasma needle is a novel design of a plasma source at atmospheric pressure to achieve a non-thermal plasma jet. The advantage of the plasma needle is that it can be operated in open air, outside a vessel. The plasma that is generated with the plasma needle is small (about one millimetre) and non-thermal, the temperature of the neutral particles and ions is in about room temperature and suitably can interact with living biological cell without damaging the cell. In this work, we report the development of a plasma needle, which is operated by a dc power source and produced a stable plasma jet on water surface. Argon gas is used to operate the plasma needle. The preliminary electrical diagnostics of the plasma needle shows that the discharge is filamentary in nature. For diagnostic of the plasma jet produced by the developed plasma needle, the produced plasma jet is directed to water surface and characterization are carried out by means of electrical discharge characteristics and optical emission spectroscopy. In this work, preliminary results of the diagnostic will be presented.

  15. Image Guidance of Flexible Tip-Steerable Needles

    Science.gov (United States)

    Kallem, Vinutha; Cowan, Noah J

    2010-01-01

    Image guidance promises to improve targeting accuracy and broaden the scope of medical procedures performed with needles. This paper takes a step toward automating the guidance of a flexible tip-steerable needle as it is inserted into human tissue. We build upon a previously proposed nonholonomic model of needles that derive steering from asymmetric bevel forces at the tip. The bevel-tip needle is inserted and rotated at its base in order to steer it in six degrees of freedom. As a first step for control, we show that the needle tip can be automatically guided to a planar slice of tissue as it is inserted. Our approach keeps the physician in the loop to control insertion speed. The distance of the needle tip position from the plane of interest is used to drive an observer-based feedback controller which we prove is locally asymptotically stable. Numerical simulations demonstrate a large domain of attraction and robustness of the controller in the face of parametric uncertainty and measurement noise. Physical experiments with tip-steerable Nitinol needles inserted into a transparent plastisol tissue phantom under stereo image guidance validate the effectiveness of our approach. PMID:20431694

  16. In vivo Monitoring of Serotonin by Nanomaterial Functionalized Acupuncture Needle

    Science.gov (United States)

    Li, Yu-Tao; Tang, Li-Na; Ning, Yong; Shu, Qing; Liang, Feng-Xia; Wang, Hua; Zhang, Guo-Jun

    2016-06-01

    Acupuncture treatment is amazing but controversial. Up to now, the mechanism of treating diseases by acupuncture and moxibustion is still unclear, especially the occurrence of the molecular events in local acupoints. Herein, we report an extremely stable microsensor by modifying carbon nanotube (CNT) to the tip surface of acupuncture needle and applying this CNT-modified acupuncture needle for real time monitoring of serotonin (5-HT) in vivo. To stabilize CNT modification on the needle tip surface, poly(3,4-ethylenedioxythiophene)(PEDOT) was employed as glue water to stick CNT on the needle. The detection limit of the CNT-modified needle was found to be approximately 50 nM and 78 nM in the PBS and the cell medium, respectively. In addition, the needle showed good selectivity to some inflammatory mediators and some electroactive molecules. For the first time, the CNT-modified needle could be directly probed into rat body for real time monitoring of 5-HT in vivo, showing a great potential for better understanding the mechanism of acupuncture treatment.

  17. Ionic solvents used in ionic polymer transducers, sensors and actuators

    OpenAIRE

    2004-01-01

    Ionic liquids are incorporated into transducers, actuators or sensors which employ the ionic polymer membranes. The ionic liquids have superior electrochemical stability, low viscosity and low vapor pressure. The transducers, actuators and sensors which utilize ionic polymer membranes solvated with ionic liquids have long term air stability. Superior results are achieved when a conductive powder and ionomer mixture is applied to the ionic polymer membrane to form the electrodes during or afte...

  18. Capacitive Ultrasonic Transducer Development for Acoustic Anemometry on Mars

    Science.gov (United States)

    Leonard-Pugh, Eurion; Wilson, C.; Calcutt, S.; Davis, L.

    2012-10-01

    Previous Mars missions have used either mechanical or thermal anemometry techniques. The moving parts of mechanical anemometers are prone to damage during launch and landing and their inertia makes them unsuited for turbulence studies. Thermal anemometers have been used successfully on Mars but are difficult to calibrate and susceptible to varying ambient temperatures. In ultrasonic anemometry, wind speed and sound speed are calculated from two-way time-of-flight measurements between pairs of transducers; three pairs of transducers are used to return a 3-D wind vector. These high-frequency measurements are highly reliable and immune from drift. Piezo-electric ultrasonic anemometers are widely used on Earth due to their full-range accuracy and high measurement frequency. However these transducers have high acoustic impedances and would not work on Mars. We are developing low-mass capacitive ultrasonic transducers for Mars missions which have significantly lower acoustic impedances and would therefore have a much stronger coupling to the Martian atmosphere. These transducers consist of a metallised polymer film pulled taught against a machined metal backplane. The film is drawn towards the backplane by a DC bias voltage. A varying signal is used on top of the DC bias to oscillate the film; generating acoustic waves. This poster will look at the operation of such sensors and the developments necessary to operate the devices under Martian conditions. Transducer performance is determined primarily by two elements; the front film and the backplane. The sensitivity of the transducer is affected by the thickness of the front film; as well as the diameter, curvature and roughness of the metal backplane. We present data on the performance of the sensors and instrument design considerations including signal shapes and transducer arrangements.

  19. A Novel Drive Option for Piezoelectric Ultrasonic Transducers

    OpenAIRE

    Diana Engelke; Bernd Oehme; Jens Strackeljan

    2011-01-01

    This paper concentrates on ultrasonic transducers, which are driven by piezoelectric ceramic rings that are arranged in a stack. A novel drive option, where the stack contains a new type of divided piezoelectric rings, is analyzed using the finite element method, prototyped, and tested. To gain a better sense of the vibration behavior, the studies focus initially on one ring and subsequently on the different possibilities to assemble the transducer. The investigations point out that natural b...

  20. Lead-Free Piezoelectric Transducers for Microelectronic Wirebonding Applications

    OpenAIRE

    Kwok, K.W.; T. Lee; Choy, S. H.; Chan, H.L.W.

    2010-01-01

    Lead-free KNLNTS and BNKLBT piezoelectric ceramic rings have been successfully prepared and used as the driving elements for fabricating ultrasonic wirebonding transducers. In order to improve the energy transfer between different parts of the transducer, titanium alloy has been used to fabricate the front and back plates. The dimensions of the ceramic rings and the titanium alloy plates have been optimized to give an operation frequency of 65 kHz. Because of the better matching of the acoust...

  1. Finite-State Complexity and the Size of Transducers

    Directory of Open Access Journals (Sweden)

    Cristian Calude

    2010-08-01

    Full Text Available Finite-state complexity is a variant of algorithmic information theory obtained by replacing Turing machines with finite transducers. We consider the state-size of transducers needed for minimal descriptions of arbitrary strings and, as our main result, we show that the state-size hierarchy with respect to a standard encoding is infinite. We consider also hierarchies yielded by more general computable encodings.

  2. Comparison of a new aspiration needle device and the Quick-Core biopsy needle for transjugular liver biopsy

    Institute of Scientific and Technical Information of China (English)

    Toru Ishikawa; Tomoteru Kamimura; Hiroteru Kamimura; Atsunori Tsuchiya; Tadayuki Togashi; Kouji Watanabe; Kei-ichi Seki; Hironobu Ohta; Toshiaki Yoshida; Noriko Ishihara

    2006-01-01

    AIM: To evaluate sample adequacy, safety, and needle passes of a new biopsy needle device compared to the Quick-Core biopsy needle for transjugular liver biopsy in patients affected by liver disease.METHODS: Thirty consecutive liver-disease patients who had major coagulation abnormalities and/or relevant ascites underwent transjugular liver biopsy using either a new needle device (18 patients) or the Quick-Core biopsy needle (12 patients). The length of the specimens was measured before fixation. A pathologist reviewed the histological slides for sample adequacy and pathologic diagnoses. The two methods' specimen adequacy and complication rates were assessed.RESULTS: Liver biopsies were technically successful in all 30 (100%) patients, with diagnostic histological core specimens obtained in 30 of 30 (100%) patients, for an overall success rate of 100%. With the new device,18 specimens were obtained, with an average of 1.1passes per patient. Using the Quick-Core biopsy needle,12 specimens were obtained, with an average of 1.8passes per patient. Specimen length was significantly longer with the new needle device than with the QuickCore biopsy needle (P < 0.05). The biopsy tissue was not fragmented in any of the specimens with the new aspiration needle device, but tissue was fragmented in 3 of 12 (25.0%) specimens obtained using the Quick-Core biopsy needle. Complications included cardiac arrhythmia in 3 (10.0%) patients, and transient abdominal pain in 4 (13.3%) patients. There were no cases of subcapsular hematoma, hemoperitoneum, or sepsis, and there was no death secondary to the procedure. In particular, no early or delayed major procedure-related complications were observed in any patient.CONCLUSION: Transjugular liver biopsy is a safe and effective procedure, and there was significant difference in the adequacy of the specimens obtained using the new needle device compared to the QuickCore biopsy needle. Using the new biopsy needle device,the specimens showed

  3. Characteristics of Children Who Undergo Intraosseous Needle Placement.

    Science.gov (United States)

    Reuter-Rice, Karin; Patrick, Dana; Kantor, Elizabeth; Nolin, Cathy; Foley, Jennifer

    2015-01-01

    Intraosseous (IO) access is a standard of care for pediatric emergencies in the absence of conventional intravenous access. Intraosseous needles provide access for resuscitation fluids and medications and are often placed in the emergency department. However, there are no studies to date that describe the characteristics of pediatric IO needle recipients or their dispositions and outcomes. This study examined the characteristics and disposition of children following IO needle placement by prehospital and emergency room teams before being transported to a children's hospital. We conducted a retrospective descriptive analysis of pediatric patients who had an IO needle placed as a part of their transport care. Data was extracted from a Level 1 trauma tertiary care children's hospital transport database from 1993 to 2009. We measured diagnosis, insertion reason, insertion time (day vs. night shift), complications, and disposition of patients after IO needle placement. There were 143 eligible patients in the study; 65% were males. Mean patient's age was 1.2 years (range: 0.01-13 years). Intraosseous needles were placed most often for patients with cardiopulmonary compromise. Of the 143 patients transported, 53% (n = 76) were placed for no intravenous access and 34% (n = 49) were placed for nonperfusing rhythm. The majority of the IO needles were placed during the daytime (0700-1900 hr), and most patients experienced no complications (n = 67; 47%). However, of those who experienced a complication, 27% were due to infiltration of the IO needle. Of those admitted to hospital, 58% (n = 83) were ultimately discharged home. Intraosseous access provides a safe and reliable method for rapidly achieving a route for administration of medications, fluids and blood products. It is a lifesaving measure with most IO needles successfully placed by referring facilities prior to transport, with few reported complications.

  4. A novel curvature-controllable steerable needle for percutaneous intervention.

    Science.gov (United States)

    Bui, Van Khuyen; Park, Sukho; Park, Jong-Oh; Ko, Seong Young

    2016-08-01

    Over the last few decades, flexible steerable robotic needles for percutaneous intervention have been the subject of significant interest. However, there still remain issues related to (a) steering the needle's direction with less damage to surrounding tissues and (b) increasing the needle's maximum curvature for better controllability. One widely used approach is to control the fixed-angled bevel-tip needle using a "duty-cycle" algorithm. While this algorithm has shown its applicability, it can potentially damage surrounding tissue, which has prevented the widespread adoption of this technology. This situation has motivated the development of a new steerable flexible needle that can change its curvature without axial rotation, while at the same time producing a larger curvature. In this article, we propose a novel curvature-controllable steerable needle. The proposed robotic needle consists of two parts: a cannula and a stylet with a bevel-tip. The curvature of the needle's path is controlled by a control offset, defined by the offset between the bevel-tip and the cannula. As a result, the necessity of rotating the whole needle's body is decreased. The duty-cycle algorithm is utilized to a limited degree to obtain a larger radius of curvature, which is similar to a straight path. The first prototype of 0.46 mm (outer diameter) was fabricated and tested with both in vitro gelatin phantom and ex vivo cow liver tissue. The maximum curvatures measured 0.008 mm(-1) in 6 wt% gelatin phantom, 0.0139 mm(-1) in 10 wt% gelatin phantom, and 0.0038 mm(-1) in cow liver. The experimental results show a linear relationship between the curvature and the control offset, which can be utilized for future implementation of this control algorithm.

  5. Home Automation System Based on Intelligent Transducer Enablers

    Directory of Open Access Journals (Sweden)

    Manuel Suárez-Albela

    2016-09-01

    Full Text Available This paper presents a novel home automation system named HASITE (Home Automation System based on Intelligent Transducer Enablers, which has been specifically designed to identify and configure transducers easily and quickly. These features are especially useful in situations where many transducers are deployed, since their setup becomes a cumbersome task that consumes a significant amount of time and human resources. HASITE simplifies the deployment of a home automation system by using wireless networks and both self-configuration and self-registration protocols. Thanks to the application of these three elements, HASITE is able to add new transducers by just powering them up. According to the tests performed in different realistic scenarios, a transducer is ready to be used in less than 13 s. Moreover, all HASITE functionalities can be accessed through an API, which also allows for the integration of third-party systems. As an example, an Android application based on the API is presented. Remote users can use it to interact with transducers by just using a regular smartphone or a tablet.

  6. Home Automation System Based on Intelligent Transducer Enablers

    Science.gov (United States)

    Suárez-Albela, Manuel; Fraga-Lamas, Paula; Fernández-Caramés, Tiago M.; Dapena, Adriana; González-López, Miguel

    2016-01-01

    This paper presents a novel home automation system named HASITE (Home Automation System based on Intelligent Transducer Enablers), which has been specifically designed to identify and configure transducers easily and quickly. These features are especially useful in situations where many transducers are deployed, since their setup becomes a cumbersome task that consumes a significant amount of time and human resources. HASITE simplifies the deployment of a home automation system by using wireless networks and both self-configuration and self-registration protocols. Thanks to the application of these three elements, HASITE is able to add new transducers by just powering them up. According to the tests performed in different realistic scenarios, a transducer is ready to be used in less than 13 s. Moreover, all HASITE functionalities can be accessed through an API, which also allows for the integration of third-party systems. As an example, an Android application based on the API is presented. Remote users can use it to interact with transducers by just using a regular smartphone or a tablet. PMID:27690031

  7. Analytical calibration of linear transducer arrays for photoacoustic tomography

    Science.gov (United States)

    Oeri, Milan; Bost, Wolfgang; Fournelle, Marc

    2015-07-01

    Tomographic photoacoustic imaging (PAT) allows to overcome the anisotropic image resolution of conventional reflection mode imaging. In order to achieve high-resolution, tomographic images, precise information on the position of each detector element is required. PAT systems that acquire signals from rotating linear transducer arrays come with inevitable transducer misalignments. Up to now, transducer orientation (x/y-tilt) and radial distance uncertainty were measured experimentally or have not been considered. Uncalibrated, these systems suffer from characteristic artifacts yielding misinterpretations of anatomic structures. Herein, we derive the artifact mathematically and investigate an analytical calibration method that enables the calculation and compensation of important transducer positioning parameters: the rotational radius and in-plane tilt. We studied the approach theoretically and evaluated the performance of the developed algorithm both on numerical and experimental data. A PAT system based on a 5-MHz linear transducer array, a multichannel electronics platform with channel data access, a NIR-emitting laser system and a rotating samples is used to demonstrate the benefit of the transducer calibration method providing isotropic resolution of 160 μm.

  8. Software for Correcting the Dynamic Error of Force Transducers

    Directory of Open Access Journals (Sweden)

    Naoki Miyashita

    2014-07-01

    Full Text Available Software which corrects the dynamic error of force transducers in impact force measurements using their own output signal has been developed. The software corrects the output waveform of the transducers using the output waveform itself, estimates its uncertainty and displays the results. In the experiment, the dynamic error of three transducers of the same model are evaluated using the Levitation Mass Method (LMM, in which the impact forces applied to the transducers are accurately determined as the inertial force of the moving part of the aerostatic linear bearing. The parameters for correcting the dynamic error are determined from the results of one set of impact measurements of one transducer. Then, the validity of the obtained parameters is evaluated using the results of the other sets of measurements of all the three transducers. The uncertainties in the uncorrected force and those in the corrected force are also estimated. If manufacturers determine the correction parameters for each model using the proposed method, and provide the software with the parameters corresponding to each model, then users can obtain the waveform corrected against dynamic error and its uncertainty. The present status and the future prospects of the developed software are discussed in this paper.

  9. Focusing of ferroelectret air-coupled ultrasound transducers

    Science.gov (United States)

    Gaal, Mate; Bartusch, Jürgen; Dohse, Elmar; Schadow, Florian; Köppe, Enrico

    2016-02-01

    Air-coupled ultrasound has been applied increasingly as a non-destructive testing method for lightweight construction in recent years. It is particularly appropriate for composite materials being used in automotive and aviation industry. Air-coupled ultrasound transducers mostly consist of piezoelectric materials and matching layers. However, their fabrication is challenging and their signal-to-noise ratio often not sufficient for many testing requirements. To enhance the efficiency, air-coupled ultrasound transducers made of cellular polypropylene have been developed. Because of its small density and sound velocity, this piezoelectric ferroelectret matches the small acoustic impedance of air much better than matching layers applied in conventional transducers. In our contribution, we present two different methods of spherical focusing of ferroelectret transducers for the further enhancement of their performance in NDT applications. Measurements on carbon-fiber-reinforced polymer (CFRP) samples and on metal adhesive joints performed with commercially available focused air-coupled ultrasound transducers are compared to measurements executed with self-developed focused ferroelectret transducers.

  10. Characterization of noncontact piezoelectric transducer with conically shaped piezoelement

    Science.gov (United States)

    Williams, James H., Jr.; Ochi, Simeon C. U.

    1988-01-01

    The characterization of a dynamic surface displacement transducer (IQI Model 501) by a noncontact method is presented. The transducer is designed for ultrasonic as well as acoustic emission measurements and, according to the manufacturer, its characteristic features include a flat frequency response range which is from 50 to 1000 kHz and a quality factor Q of less than unity. The characterization is based on the behavior of the transducer as a receiver and involves exciting the transducer directly by transient pulse input stress signals of quasi-electrostatic origin and observing its response in a digital storage oscilloscope. Theoretical models for studying the response of the transducer to pulse input stress signals and for generating pulse stress signals are presented. The characteristic features of the transducer which include the central frequency f sub o, quality factor Q, and flat frequency response range are obtained by this noncontact characterization technique and they compare favorably with those obtained by a tone burst method which are also presented.

  11. Experimental Evaluation of Three Designs of Electrodynamic Flexural Transducers

    Science.gov (United States)

    Eriksson, Tobias J. R.; Laws, Michael; Kang, Lei; Fan, Yichao; Ramadas, Sivaram N.; Dixon, Steve

    2016-01-01

    Three designs for electrodynamic flexural transducers (EDFT) for air-coupled ultrasonics are presented and compared. An all-metal housing was used for robustness, which makes the designs more suitable for industrial applications. The housing is designed such that there is a thin metal plate at the front, with a fundamental flexural vibration mode at ∼50 kHz. By using a flexural resonance mode, good coupling to the load medium was achieved without the use of matching layers. The front radiating plate is actuated electrodynamically by a spiral coil inside the transducer, which produces an induced magnetic field when an AC current is applied to it. The transducers operate without the use of piezoelectric materials, which can simplify manufacturing and prolong the lifetime of the transducers, as well as open up possibilities for high-temperature applications. The results show that different designs perform best for the generation and reception of ultrasound. All three designs produced large acoustic pressure outputs, with a recorded sound pressure level (SPL) above 120 dB at a 40 cm distance from the highest output transducer. The sensitivity of the transducers was low, however, with single shot signal-to-noise ratio (SNR)≃15 dB in transmit–receive mode, with transmitter and receiver 40 cm apart. PMID:27571075

  12. Piezoelectric films for high frequency ultrasonic transducers in biomedical applications.

    Science.gov (United States)

    Zhou, Qifa; Lau, Sienting; Wu, Dawei; Shung, K Kirk

    2011-02-01

    Piezoelectric films have recently attracted considerable attention in the development of various sensor and actuator devices such as nonvolatile memories, tunable microwave circuits and ultrasound transducers. In this paper, an overview of the state of art in piezoelectric films for high frequency transducer applications is presented. Firstly, the basic principles of piezoelectric materials and design considerations for ultrasound transducers will be introduced. Following the review, the current status of the piezoelectric films and recent progress in the development of high frequency ultrasonic transducers will be discussed. Then details for preparation and structure of the materials derived from piezoelectric thick film technologies will be described. Both chemical and physical methods are included in the discussion, namely, the sol-gel approach, aerosol technology and hydrothermal method. The electric and piezoelectric properties of the piezoelectric films, which are very important for transducer applications, such as permittivity and electromechanical coupling factor, are also addressed. Finally, the recent developments in the high frequency transducers and arrays with piezoelectric ZnO and PZT thick film using MEMS technology are presented. In addition, current problems and further direction of the piezoelectric films for very high frequency ultrasound application (up to GHz) are also discussed.

  13. Home Automation System Based on Intelligent Transducer Enablers.

    Science.gov (United States)

    Suárez-Albela, Manuel; Fraga-Lamas, Paula; Fernández-Caramés, Tiago M; Dapena, Adriana; González-López, Miguel

    2016-09-28

    This paper presents a novel home automation system named HASITE (Home Automation System based on Intelligent Transducer Enablers), which has been specifically designed to identify and configure transducers easily and quickly. These features are especially useful in situations where many transducers are deployed, since their setup becomes a cumbersome task that consumes a significant amount of time and human resources. HASITE simplifies the deployment of a home automation system by using wireless networks and both self-configuration and self-registration protocols. Thanks to the application of these three elements, HASITE is able to add new transducers by just powering them up. According to the tests performed in different realistic scenarios, a transducer is ready to be used in less than 13 s. Moreover, all HASITE functionalities can be accessed through an API, which also allows for the integration of third-party systems. As an example, an Android application based on the API is presented. Remote users can use it to interact with transducers by just using a regular smartphone or a tablet.

  14. Microelectronics mounted on a piezoelectric transducer: method, simulations, and measurements.

    Science.gov (United States)

    Johansson, Jonny; Delsing, Jerker

    2006-01-01

    This paper describes the design of a highly integrated ultrasound sensor where the piezoelectric ceramic transducer is used as the carrier for the driver electronics. Intended as one part in a complete portable, battery operated ultrasound sensor system, focus has been to achieve small size and low power consumption. An optimized ASIC driver stage is mounted directly on the piezoelectric transducer and connected using wire bond technology. The absence of wiring between driver and transducer provides excellent pulse control possibilities and eliminates the need for broad band matching networks. Estimates of the sensor power consumption are made based on the capacitive behavior of the piezoelectric transducer. System behavior and power consumption are simulated using SPICE models of the ultrasound transducer together with transistor level modelling of the driver stage. Measurements and simulations are presented of system power consumption and echo energy in a pulse echo setup. It is shown that the power consumption varies with the excitation pulse width, which also affects the received ultrasound energy in a pulse echo setup. The measured power consumption for a 16 mm diameter 4.4 MHz piezoelectric transducer varies between 95 microW and 130 microW at a repetition frequency of 1 kHz. As a lower repetition frequency gives a linearly lower power consumption, very long battery operating times can be achieved. The measured results come very close to simulations as well as estimated ideal minimum power consumption.

  15. Exact series model of Langevin transducers with internal losses.

    Science.gov (United States)

    Nishamol, P A; Ebenezer, D D

    2014-03-01

    An exact series method is presented to analyze classical Langevin transducers with arbitrary boundary conditions. The transducers consist of an axially polarized piezoelectric solid cylinder sandwiched between two elastic solid cylinders. All three cylinders are of the same diameter. The length to diameter ratio is arbitrary. Complex piezoelectric and elastic coefficients are used to model internal losses. Solutions to the exact linearized governing equations for each cylinder include four series. Each term in each series is an exact solution to the governing equations. Bessel and trigonometric functions that form complete and orthogonal sets in the radial and axial directions, respectively, are used in the series. Asymmetric transducers and boundary conditions are modeled by using axially symmetric and anti-symmetric sets of functions. All interface and boundary conditions are satisfied in a weighted-average sense. The computed input electrical admittance, displacement, and stress in transducers are presented in tables and figures, and are in very good agreement with those obtained using atila-a finite element package for the analysis of sonar transducers. For all the transducers considered in the analysis, the maximum difference between the first three resonance frequencies calculated using the present method and atila is less than 0.03%.

  16. An analytical model of a longitudinal-torsional ultrasonic transducer

    Science.gov (United States)

    Al-Budairi, Hassan; Lucas, Margaret

    2012-08-01

    The combination of longitudinal and torsional (LT) vibrations at high frequencies finds many applications such as ultrasonic drilling, ultrasonic welding, and ultrasonic motors. The LT mode can be obtained by modifications to the design of a standard bolted Langevin ultrasonic transducer driven by an axially poled piezoceramic stack, by a technique that degenerates the longitudinal mode to an LT motion by a geometrical alteration of the wave path. The transducer design is developed and optimised through numerical modelling which can represent the geometry and mechanical properties of the transducer and its vibration response to an electrical input applied across the piezoceramic stack. However, although these models can allow accurate descriptions of the mechanical behaviour, they do not generally provide adequate insights into the electrical characteristics of the transducer. In this work, an analytical model is developed to present the LT transducer based on the equivalent circuit method. This model can represent both the mechanical and electrical aspects and is used to extract many of the design parameters, such as resonance and anti-resonance frequencies, the impedance spectra and the coupling coefficient of the transducer. The validity of the analytical model is demonstrated by close agreement with experimental results.

  17. A New Flavonoid in Pine Needles of Cedrus deodara

    Institute of Scientific and Technical Information of China (English)

    LIU Dong-yan; SHI Xiao-feng; WANG Dong-dong; MA Qu-huan; ZHANG Jun-min; LI Chong

    2011-01-01

    Objective To study the chemical constituents of flavonoids in pine needles of Cedrus deodara.Methods Flavonoids were isolated and purified from ethyl acetate extract of pine needles by chromatography on silica gel and Sephadex LH-20.Their structures were identified on the basis of spectroscopic analysis and chemical evidence.Results Five flavonoids were isolated and purified.Their structures were identified as cedrusone A(1),myricetin(2),2R,3R-dihydromyricetin(3),quercctin(4),and 2R,3R-dihydroquercetin(5).Conclusion Compound 1 is a new compound.Compounds 2-5 are isolated from pine needles of this genus for the first time.

  18. Diagenesis of conifer needles in a coastal marine environment

    Science.gov (United States)

    Hedges, John I.; Weliky, K.

    1989-10-01

    Physically intact fir, hemlock and cedar needles were isolated from different horizons of a sediment core from a coastal marine bay (Dabob Bay, Washington State, U.S.A.) and from nearby trees and forest litter. Green fir, hemlock and cedar needles were all characterized by glucose-rich aldose mixtures (~30% of tissue carbon), the production of vanillyl and cinnamyl CuO-derived phenols (~8% of tissue carbon) and the presence of both pinitol and myo-inositol (1-2% of tissue carbon). Needles from forest litter were enriched in lignin phenols and non-glucose aldoses and depleted in glucose and cyclitols. The sediment core contained an average of 10 mg/1 of physically intact fir, hemlock and cedar needles, which occurred in similar relative abundances and accounted for less than 1% of the total nonwoody gymnosperm tissue. Compared to the green and litter counterparts, all sedimentary needles were greatly depleted in cyclitols, glucose and p-coumaric acid and enriched in vanillyl phenol precursors. The degree of elevation of vanillyl phenol yield from the degraded needles was used to estimate minimal carbon losses from the samples, which ranged from near 40% for needle litter to almost 70% for the deepest (~100 years old) sedimentary fir/hemlock samples. Although downcore increases in carbon loss and refractory organic components indicated in situ diagenesis, the bulk of overall degradation occurred either on land or during the first 10-20 years after deposition. Atomic C/N ratios of degraded needles were lower than for green counterparts, but nitrogen was lost overall. These relative changes indicate the following stability series: vanillyl phenols > N > ferulic acid, p-hydroxy phenols, most aldoses and bulk tissue > glucose and p-coumaric acid > cyclitols (near 100% loss). Vanillic acid to vanillin ratios, (Ad/Al)v, of the green fir and hemlock needles were unusually high (0.36-0.38) and decreased downcore. Diagenesis also decreased the cinnamyl/vanillyl phenol ratio

  19. Ultrasonic Transducers for Air and Underwater Communication.

    Science.gov (United States)

    Koosha, Abdolrahim

    Available from UMI in association with The British Library. The performance of a novel radiator capable of producing ultrasonic waves in air and liquids has been investigated. For commercial transducers when operating in air or liquids, impedance matching is the necessary condition for maximum transfer of energy to the medium (thus no standing waves are involved). However, for this radiator the formation of the mechanical standing waves on it is the key condition for directional radiation of energy into the surrounding environment. Under this condition the radiator exhibits a practical conversion of electrical energy into ultrasound. To further improve the performance of the radiator the wavelength coincidence condition must be satisfied. This condition implies that the wavelength of the bending vibration developed on the blade to be the same as that in the medium to which it is coupled. Consequently, an end-fire radiation pattern is obtained. The theory of this when applied to water and also for a double blade configuration are presented. The main component of the radiator consists of a cantilever blade on which a pair of piezoelectric (PZT) ceramic bars are fixed. These the so called excitation gauges, are fixed on both sides of a thin rectangular metal blade near the clamped end. When wavelength coincidence condition is fulfilled, the radiator transmits ultrasonic wave in a highly directional pattern. The direction of propagation of ultrasound is solely steered by frequency of the applied signal. System imperfections such as inter modal coupling when used underwater are considered. An analytical approach is developed to investigate the performance of the radiator for transmission of digital signals in air as well as in water. This method is used to evaluate the efficiency of the device as a suitable means for communication between divers or a diver and an underwater stationary station. Amplitude modulation of speech signals demonstrated the capabilities of a new

  20. Ultrasound guided fine-needle aspiration cytology of breast lesions

    OpenAIRE

    C. Pagani; Coscia, D. R.; Dellabianca, C.; Bonardi, M.; Alessi, S.; Calliada, F.

    2011-01-01

    Breast biopsy consists in the collection of cells or tissue fragments from a breast lesion and their analysis by a pathologist. There are several types of breast biopsy defined on the basis of the type of needle used: fine-needle aspiration and biopsy performed with a spring-based needle. This article focuses on fine-needle aspiration performed under sonographic guidance.

  1. A High-Voltage Class D Audio Amplifier for Dielectric Elastomer Transducers

    DEFF Research Database (Denmark)

    Nielsen, Dennis; Knott, Arnold; Andersen, Michael A. E.

    2014-01-01

    Dielectric Elastomer (DE) transducers have emerged as a very interesting alternative to the traditional electrodynamic transducer. Lightweight, small size and high maneuverability are some of the key features of the DE transducer. An amplifier for the DE transducer suitable for audio applications...

  2. Concurrent fine needle aspirations and core needle biopsies: a comparative study of substrates for next-generation sequencing in solid organ malignancies.

    Science.gov (United States)

    Roy-Chowdhuri, Sinchita; Chen, Hui; Singh, Rajesh R; Krishnamurthy, Savitri; Patel, Keyur P; Routbort, Mark J; Manekia, Jawad; Barkoh, Bedia A; Yao, Hui; Sabir, Sharjeel; Broaddus, Russell R; Medeiros, L Jeffrey; Staerkel, Gregg; Stewart, John; Luthra, Rajyalakshmi

    2017-01-13

    Minimally invasive procedures, such as fine needle aspiration and core needle biopsy, are commonly used for the diagnosis in solid organ malignancies. In the era of targeted therapy, it is crucial for molecular testing to be performed on these limited volume specimens. Although several recent studies have demonstrated the utility of small biopsy specimens for molecular testing, there remains debate as to whether core needle biopsy specimens are more reliable than fine needle aspiration for molecular studies. In this study, we reviewed concurrently acquired fine needle aspiration and core needle biopsy samples (n=24), and compared overall cellularity, tumor fraction, and the results of next-generation sequencing. All somatic mutations detected in core needle biopsy samples were also detected in fine needle aspiration samples. The estimated tumor fraction was significantly higher in fine needle aspiration smears than core needle biopsy samples (P=0.003), whereas the overall DNA yield from smears was significantly lower than that obtained from the core needle biopsy specimens (P=0.01). The normalized average amplicon coverage for the genes analyzed was significantly higher in cytology smears than paired core needle biopsy samples, with lower numbers of failed amplicons and higher overall mutation allelic frequencies seen in the former. We further evaluated 100 malignant fine needle aspiration and core needle biopsy samples, acquired concurrently, for overall cellularity and tumor fraction. Overall cellularity and tumor fraction of fine needle aspiration samples was significantly higher than concurrently acquired core needle biopsy samples (Pcore needle biopsy samples. Cytologic specimens, therefore, should be better integrated into routine molecular diagnostics workflow to maximize limited tissues for clinically relevant genomic testing.Modern Pathology advance online publication, 13 January 2017; doi:10.1038/modpathol.2016.228.

  3. TREATMENT OF 18 CASES OF TRIGEMINAL NEURALGIA WITH ELONGATED NEEDLE

    Institute of Scientific and Technical Information of China (English)

    李建兰; 阎巍; 岳仍丽

    2004-01-01

    In this paper, a total of 18 cases of primary trigeminal neuralgia were treated with elongated needle. Of the 18 cases, 5 were male and 15 female, ranging in age from 27 to 58 years and in disease duration from 3 days to 8 years. Main acupoints used were Taiyang (EX-HN 5) to Xiaguan (ST 7, for penetration needling), Xiajiache, Fengchi (GB 20), Yanglingquan (GB 34) and Taichong (LR 3). The treatment was given once daily, with 12 sessions being a therapeutic course. After 2 courses of treatment, of the 18 cases, 10 cases were cured, 7 experienced improvement in pain and one failed in the treatment, with an effective rate of 94.4%. The key point for treating trigeminal neuralgia is applying penetrative needling from EX-HN 5 to ST 7 to achieve ideal needling sensations.

  4. Warm-Needling Technique for Peripheral Facial Paralysis

    Institute of Scientific and Technical Information of China (English)

    WANG Chuan-nian; ZHOU Jing; SHAO Ming-hai

    2007-01-01

    Objective: To observe the therapeutic effects of warm-needling technique on peripheral facial paralysis. Methods: Warm-needling technique and electroacupuncture were employed to treat 30 cases of facial paralysis, respectively. The same acupoints, Cuanzhu(BL 2)towards Yuyao(Ex-HN 4), Yingxiang(LI 20) towards Xiaguan(ST 7), Taiyang(Ex-HN 5)towards Xuanlu(GB 5), Dicang(ST 4) towards Jiache(ST 6), and Chengjiang(CV 24) towards Daying(ST 5), were used. Results: After 33 treatments, the warm-needling technique has an effective rate of 83.3%, while the electroacupuncture 67.7%. Conclusion: The therapeutic effect of warm-needling technique was better than that of electroacupuncture method.

  5. [Quintessence of academician SHI Xue-min's acupoint needling method].

    Science.gov (United States)

    Yang, Ming-Xing

    2008-10-01

    Under guidance of the traditional theories of acupuncture and modern knowledge of anatomy and in combination with his long-term clinical practice and clinical researches, academician SHI Xue-min formulates scien tific and strict acupuncture methods and corresponding quantitative requirement for the acupoints for treatment of stroke and relative diseases and symptoms, including patient's posture, doctor's posture, angle of needle insertion, manipulation, amount of arrival of qi, etc. Correct grasping these needling methods of acupoints is a key to learn and understand SHI Xue-min's Acupuncture Science and "Xingnao Kaiqiao" needling method and quantitative acu puncture manipulation theory. In this paper, SHI Xue-min's partial experiences on needling acupoints are introduced.

  6. Percutaneous transhepatic biliary drainage using large needle: Complications and usefulness

    Energy Technology Data Exchange (ETDEWEB)

    Park, Noh Kyoung; Lim, Hyun Yang; Lee, Ji Yeon; Lee, Kil Jun; Tae, Seok; Shin, Kyoung Ja; Lee, Sang Chun [Seoul Red Cross Hospital, Seoul (Korea, Republic of)

    1994-06-15

    To analyse complications and to review usefulness of large needle(18G) in percutaneous transhepatic biliary drainage(PTBD). 46 patients underwent PTBD in 52 occasions using large needle. 44 of 46 patients had either definite or suspicious malignant biliary obstruction, and most patients were poor in general condition. Complications were classified as acute type if developed within 30 days and as delayed type if developed after 30 days. Acute type was subdivided into severe and mild forms. Severe forms of complications were death(5.8%), septicemia(3.8%), and bile peritonitis(1.9%). There were not different from the rate of complication in PTBD using fine needle but the procedure was much more simple. We PTBD using large needle is a simple and safe procedure for prompt bile decompression.

  7. Guidelines for processing and reporting of prostatic needle biopsies

    NARCIS (Netherlands)

    Th.H. van der Kwast (Theo); C. Lopes; C. Santonja; C.G. Pihl; I. Neetens; P. Martikainen (Pekka); S. di Lollo; L. Bubendorf; R.F. Hoedemaeker

    2003-01-01

    textabstractThe reported detection rate of prostate cancer, lesions suspicious for cancer, and prostatic intraepithelial neoplasia (PIN) in needle biopsies is highly variable. In part, technical factors, including the quality of the biopsies, the tissue processing, and histopatholo

  8. [Doctor HUANG Shi-ping's acupuncture with golden needles].

    Science.gov (United States)

    Chen, Teng-Fei; Ma, Zeng-Bin; Xin, Si-Yuan; Zhu, Jiang

    2013-08-01

    Taking Doctor HUANG Shi-ping as the representative, the school of Huang's golden needle is based on Chinese martial art. Golden needles are adopted as main tool. Attaching great importance on the combination of acupuncture and moxibustioin, it is also characterized with penetrating needling with long needles. Through the development of three generations, it once outshone other schools in the field of acupuncture, and became famous all over the world. It made great contribution to the development of the course of acupuncture. However, with the development of the history, the form of acupuncture education as well as apparatus were all undergone an unified reform. Therefore, Doctor HUANG Shi-ping's acupuncture school be lost gradually.

  9. A pilot/introducer needle for central vein cannulation.

    Science.gov (United States)

    Suzuki, T; Kanazawa, M; Kinefuchi, Y; Fukuyama, H; Takiguchi, M; Yamamoto, M; Abe, K; Okuda, Y

    1995-12-01

    A kit for safe and easy insertion of a central vein cannula was devised. A small gauge (22 gauge) metal pilot needle was equipped with a Y-shaped hub which had a side-port to accept a small gauge (0.46 mm) Seldinger guide wire. Once the needle reached the vein, guidewire was threaded in through the side-port. There was no need to remove the pilot needle and no need to repeat vein puncture with a larger-bore needle. Three puncture methods were used with the kit: (1) the central approach via the internal jugular vein, (2) the supraclavicular approach via the junction of the internal jugular vein and subclavian vein, and (3) the infraclavicular approach via the subclavian vein. Each method was used on 20 patients, for total of 60 patients, with a high success rate. Less than 3 minutes were required from puncture to catheter insertion. No serious complications were encountered.

  10. THEORETICAL ANALYSIS ON THE DEPTH OF NEEDLE-INSERTION

    Institute of Scientific and Technical Information of China (English)

    LIN Wen-jian

    2005-01-01

    In the present paper, the author sums up and analyzes descriptions about needle-insertion depth in Chinese classical medical book Huang Di Nei Jing (The Yellow Emperor's Internal Classic). In many chapters of Nei Jing, the needle-insertion depth is stressed to be various according to 1) the deficiency or excess of syndromes, 2) the patients' constitution, 3) the severity of disease, 4) the duration of disease, 5) the location of disease, 6) the patient's age, 7) the location of the needled acupoint, 8) the season, 9) the patient's temperament, 10) the pulse condition, 11) the state of "Deqi", and 12) the location of the running course of meridians. In addition, different kinds of diseases and different stages of diseases also need different depths of needle insertion, different manipulating skills and different stimulating quantity.

  11. NEEDLE ANATOMY CHANGES WITH INCREASING TREE AGE IN DOUGLAS FIR

    Science.gov (United States)

    Morphological differences between old growth and sapling (Pseudotsuga menziesii, (Mirb.) Franco) Douglas fir trees may extend to differences in needle anatomy. We used microscopy with image analysis to compare and quantify anatomical parameters in cross-sections of previous year...

  12. Ralph L. Huber, DMD: forgotten inventor of the "Tuohy" needle.

    Science.gov (United States)

    Lubisich, Josef W

    2004-07-01

    The hypodermic needle popularized by Edward Tuohy, MD for use in his method of continuous spinal anesthesia has been incorrectly called the "Tuohy needle" since he first popularized it in 1945. It was recently determined that Ralph L. Huber, a Seattle dentist, was the inventor of this widely used needle. However, very little is known about Huber. There is no mention of him in the medical literature, and until recently, he was forgotten. Through the location of various primary sources, including the original needle point invented by Dr. Huber, this essay introduces the fascinating life of Dr. Huber, and also his personal notes about his inventions. Not only was he a prominent Seattle dentist, but also a prolific inventor.

  13. Ultrasonic flowmeters: temperature gradients and transducer geometry effects.

    Science.gov (United States)

    Willatzen, M

    2003-03-01

    Ultrasonic flowmeter performance is addressed for the case of cylindrically shaped flowmeters employing two reciprocal ultrasonic transducers A and B so as to measure time-of-flight differences between signals transmitted from transducer A towards B followed by an equivalent signal transmitted from transducer B towards A. In the case where a liquid flows through the flowmeter's measuring section ("spoolpiece"), the arrival times of the two signals differ by an amount related to the flow passing between the two transducers. Firstly, a detailed study of flow measurement errors with mean flow in the laminar flow regime is carried out as a function of the mode index and the transducer diameter/cylinder diameter ratio in the case where no temperature gradients are present in the flowmeter sensor. It is shown that all modes except the fundamental mode overestimate the mean flow by a factor of 33.33% while excitation of the fundamental mode solely give error-free measurements. The immediate consequences are that the flowmeter error decreases as the transducer diameter/cylinder diameter ratio approaches 1 from 0 reflecting the fact that the excitation level of the fundamental mode increases from almost 0 to 1 as this ratio approaches 1 from 0. Secondly, the effect on flowmeter performance due to flow-induced temperature gradients is examined. It is shown that the presence of temperature gradients leads to flowmeter errors at the higher-flow values even in the case where the fundamental mode is the only mode excited. It is also deduced that flowmeter errors in general depend on the distance between transducers A and B whether temperature gradients exist or not. This conclusion is not reflected in the usual definition of flowmeter errors given by the so-called mode-dependent deviation of measurement introduced in earlier works.

  14. Enterobacter aerogenes Needle Stick Leads to Improved Biological Management System

    Energy Technology Data Exchange (ETDEWEB)

    Johanson, Richard E.

    2004-08-01

    A laboratory worker who received a needle stick from a contaminated needle while working with a culture containing Enterobactor aerogenes developed a laboratory acquired infection. Although this organism has been shown to cause community and nosocomial infections, there have been no documented cases of a laboratory acquired infections. Lessons learned from the event led to corrective actions which included modification of lab procedures, development of a biological inventory tracking and risk identification system and the establishment of an effective biological safety program.

  15. Ultrasound guided needle biopsy of skeletal muscle in neuromuscular disease

    DEFF Research Database (Denmark)

    Lindequist, S; Schrøder, H D; Larsen, C

    1990-01-01

    Guided by ultrasonography percutaneous needle biopsy of skeletal muscle was performed in 24 patients, using the one hand held Biopty system and a 2 mm Tru-Cut needle. The specimens were graded with regard to diagnostic quality and utility and almost all specimens (96%) were of highest quality....... The use of ultrasonography was helpful in selecting a suitable area for the biopsy and vascular structures could be avoided. The procedure was well tolerated and easy to perform, and no complications were recorded....

  16. Clinical Application of Movement-needling Technique: Stiff Neck

    Institute of Scientific and Technical Information of China (English)

    LIU Yan

    2005-01-01

    @@ Movement-needling Technique, a new acupuncture therapy, is based on traditional acupuncture therapy and anatomical principle, combining acupuncture and movement. Combining disease and syndrome differentiation, and integrating TCM and Western medical diagnosis, this technique is used to treat different diseases mainly with acupuncture,combining some movement in needling. These movements not only boost therapeutic effects of acupuncture, but also add new contents to traditional acupuncture.

  17. Analysis on enzymatic browning in pine needles

    Energy Technology Data Exchange (ETDEWEB)

    Kong, K.H.; Park, H.J.; Choi, S.S.; Cho, S.H. [Chung-Ang University, Seoul (Korea); Kim, Y.T. [Aoyama Gakuin University, Tokyo (Japan)

    1999-06-01

    Tyrosinases are related to the enzymatic browning of plants and attract the major scientific interest for the prevention of it. Three tyrosinase isozymes (P{sub 1}, P{sub 2} and P{sub 3}) from pine needles were purified to homogeneity and characterized the factors that affect their activities. The L-ascorbic acid and {beta}-mercaptoethanol notably inhibited the enzymatic activities of the three isozymes. The sodium diethyldithiocarbamate was a competitive inhibitor of isozymes with the K{sub i} values of P{sub 1}(0.30 mM), P{sub 2}(0.015 mM) and P{sub 3}(0.019 mM), respectively. Their enzyme activities were however, increased by the addition of most metal ions. The optimum pH for the three isozymes was 9.0{approx}9.5 and the optimum temperatures ranged from 55 to 60{sup o} C using L-DOPA as substrate. 15 refs., 3 figs., 2 tabs.

  18. Fine needle aspiration cytology of dermal cylindroma

    Directory of Open Access Journals (Sweden)

    Parikshaa Gupta

    2014-01-01

    Full Text Available In this paper, we have described fine needle aspiration cytology (FNAC of a rare case of dermal cylindroma. A 40-year-old female presented with a lateral mid-cervical swelling fixed to the skin. FNAC smears showed multiple clusters of small, round to oval cells with hyperchromatic nuclei, inconspicuous nucleoli and scant cytoplasm. In addition, the background showed deposits of basement membrane type material. This was dark magenta colored pinkish globular material. The globules were occasionally surrounded by the basal type of cells. Occasional cells with elongated nuclei were also noted. Cytological diagnosis of skin adnexal tumor possibly cylindroma was offered. Subsequent histopathology of the swelling showed sheets and clusters of cells in a jigsaw puzzle-like fashion. Deposition of abundant basement membrane-like material was noted in between the tumor cells. A diagnosis of cylindorma was offered. FNAC along with the subcutaneous location of the tumor and absence of primary salivary gland tumor may help to diagnose such rare case.

  19. Percutaneous transhepatic cholangiography using fine needle

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Kyoo Byung; Kim, Yun Hwan; Lee, Nam Joon; Suh, Won Hyuck [College of Medicine, Korea University, Seoul (Korea, Republic of)

    1980-12-15

    In recent years, percutaneous transhepatic cholangiography (PTC) using fine needle has become widely employed as the procedure of choice for direct opacification of the biliary trees because of its high success rate, easy performance and relative low complication rate. Authors present the clinical and PTC findings of experienced cases during last four years, from May 1976 to June 1980, at the Department of Radiology, Korea University Hospital. We tried to study of PTC in 44 cases, 32 males and 12 females, and succeeded in visualization of bile ducts in 41 cases, but the other three cases were failed to visualize the bile ducts. Final confirmative diagnosis was achieved in 29 cases by operation, laparoscopy and other clinical methods. The PTC diagnosis was correct in 24 of 29 cases, and the others were incorrect. The 29 final diagnosis was including 13 cases of biliary stones, 6 cases of biliary cancer, 3 cases of pancreatic cancer, 3 cases of clonorchiasis, one case of CBD ascariasis and 3 cases of others. Incorrect PTC diagnosis was made in five cases. They were one case of nonvisualized intrahepatic stones, one case of hepatoma PTC diagnosed as cholangiocarcinoma, one case of pancreatic cancer diagnosed as cholangiocarcinoma, one case of clonorchiasis diagnosed as biliary stones and one case of normal CBD which was diagnosed as distal CBD cancer. And we experienced one case of bile peritonitis as complication, who was 35 year-old female patient with multiple CBD stones, and aspirated about 500ml of bile stained ascites during operation.

  20. Fine needle aspiration cytology in leprosy

    Directory of Open Access Journals (Sweden)

    Prasad PVS

    2008-01-01

    Full Text Available Background: Laboratory diagnosis of leprosy by slit skin smear and skin biopsy is simple but both techniques have their own limitations. Slit skin smear is negative in paucibacillary cases whereas skin biopsy is an invasive technique. Fine needle aspiration cytology (FNAC from skin lesions in leprosy with subsequent staining with May-Grunwald-Giemsa (MGG stain has been found useful. Aim: To evaluate the possible role of cytology in classifying leprosy patients. Methods: Seventy-five untreated cases of leprosy attending the outpatient department were evaluated. Smears were taken from their skin lesions and stained using the MGG technique. Skin biopsy was also done from the lesions, which was compared with cytology smears. Results: A correlation of clinical features with FNAC was noticed in 87.5% of TT, 92.1% of BT, 81% of BL, and 66% of LL cases. Correlation of clinical with histopathological diagnoses revealed 12.5% specificity in TT leprosy, 55.3% in BT, 52.4% in BL and 50% in LL, and 100% in neuritic and histoid leprosy cases. Both correlations were found to be statistically significant by paired t test analysis. Thus, it was possible to distinguish the tuberculoid types by the presence of epithelioid cells and the lepromatous types by the presence of lymphocytes and foamy macrophages. Conclusion: FNAC may be used to categorize the patients into paucibacillary and multibacillary types, but is not a very sensitive tool to classify the patients across the Ridley-Jopling spectrum.

  1. Needle core biopsy for breast lesions: An audit of 467 needle core biopsies

    Directory of Open Access Journals (Sweden)

    Selvi Radhakrishna

    2013-01-01

    Full Text Available Background: Breast cancer is the commonest cancer among women in urban India. Triple assessment includes clinical, radiological and cytological assessment of breast lesions. Guided core needle biopsy has replaced fine needle aspiration cytology in most of the western countries. In resource poor countries FNAC is still a very valuable and cost effective method to diagnose breast lesions. Pitfalls include increased rates of non diagnostic smears, and inadequate smears. Further procedures may be required and this increases the cost, anxiety and delay in diagnosis. Aims: The aim of this study is to analyze the concordance of radiological and histopathology findings in BI-RADS category 3,4,5 lesions following a core biopsy. Materials and Methods: Data was retrospectively collected from consecutive symptomatic and opportunistic screen detected patients with abnormalities who underwent ultrasound guided interventional procedures from Jan 2010 to Aug 2011. Symptomatic patients underwent clinical examination, mammogram and breast ultrasound. Women under 35 years of age had only breast ultrasound. Core biopsy was performed under ultrasound guidance or clinically by a breast surgeon/ radiologist for BI-RADS category 3,4,5 lesions. Statistical Methods: Chi square test was done to show the strength of association of imaging findings and histopathology results of core biopsy. Results: 437 patients were symptomatic and 30 patients had screen detected abnormalities. The positive predictive value for BI-RADS 5 lesions for malignancy is 93.25% and the negative predictive value of BI-RADS category 3 lesions for cancer is 98.4%. False negative diagnosis on core biopsy was 0.85%. We were able to defer surgery in 60% of the patients with a clear radiological and pathological benign diagnosis. Conclusion: The PPV and NPV for cancer is high with needle core biopsy in BI-RADS 3,4,5 lesions. Where there is no discordance between clinical, radiology and pathology findings

  2. Neuromuscular Damage and Repair after Dry Needling in Mice

    Directory of Open Access Journals (Sweden)

    Ares Domingo

    2013-01-01

    Full Text Available Objective. Some dry needling treatments involve repetitive and rapid needle insertions into myofascial trigger points. This type of treatment causes muscle injury and can also damage nerve fibers. The aim of this study is to determine the injury caused by 15 repetitive punctures in the muscle and the intramuscular nerves in healthy mouse muscle and its ulterior regeneration. Methods. We repeatedly needled the levator auris longus muscle of mice, and then the muscles were processed with immunohistochemistry, methylene blue, and electron microscopy techniques. Results. Three hours after the dry needling procedure, the muscle fibers showed some signs of an inflammatory response, which progressed to greater intensity 24 hours after the procedure. Some inflammatory cells could still be seen when the muscle regeneration was almost complete seven days after the treatment. One day after the treatment, some changes in the distribution of receptors could be observed in the denervated postsynaptic component. Reinnervation was complete by the third day after the dry needling procedure. We also saw very fine axonal branches reinnervating all the postsynaptic components and some residual sprouts the same day. Conclusion. Repeated dry needling punctures in muscle do not perturb the different stages of muscle regeneration and reinnervation.

  3. Mechanics of dynamic needle insertion into a biological material.

    Science.gov (United States)

    Mahvash, Mohsen; Dupont, Pierre E

    2010-04-01

    During needle-based procedures, transitions between tissue layers often lead to rupture events that involve large forces and tissue deformations and produce uncontrollable crack extensions. In this paper, the mechanics of these rupture events is described, and the effect of insertion velocity on needle force, tissue deformation, and needle work is analyzed. Using the J integral method from fracture mechanics, rupture events are modeled as sudden crack extensions that occur when the release rate J of strain energy concentrated at the tip of the crack exceeds the fracture toughness of the material. It is shown that increasing the velocity of needle insertion will reduce the force of the rupture event when it increases the energy release rate. A nonlinear viscoelastic Kelvin model is then used to predict the relationship between the deformation of tissue and the rupture force at different velocities. The model predicts that rupture deformation and work asymptotically approach minimum values as needle velocity increases. Consequently, most of the benefit of using a higher needle velocity can be achieved using a finite velocity that is inversely proportional to the relaxation time of the tissue. Experiments confirm the analytical predictions with multilayered porcine cardiac tissue.

  4. Nursing and safety of silver needle diathermy treating ankylosing spondylitis.

    Science.gov (United States)

    Ning, Huaxiu; Wang, Yun; Yuan, Yiwen; Ning, Huaying

    2015-03-01

    This paper aims to discuss the nursing and safety of silver needle diathermy in the treatment for ankylosing spondylitis. We nursed 46 patients with ankylosing spondylitis treated with silver needle diathermy. Specific nursing was focused on physical condition evaluation and mental nursing before treatment, observation during and after treatment, diet nursing, needle eye nursing, functional training and propaganda and education when discharged. The result suggested that all the patients received mental nursing, diet guide, skin care, health education, functional training and follow-up visit from the nurse and all of them could endure silver needle diathermy as discomfort or drug allergy was barely found, so were slight scald and skin infection nearby the needle eye caused by fainting during acupuncture, accidental puncture or overheat. Follow-up visit showed that no patient suffered obvious untoward effect and the pain, joint range of motion and living condition were distinctly improved a week after discharging. In conclusion, during the treatment for ankylosing spondylitis applying silver needle diathermy, the nursing before, during and after the treatment can obviously reduce the complication, accelerate the recovery, which is highly safe.

  5. Antioxidant, antimutagenic, and antitumor effects of pine needles (Pinus densiflora).

    Science.gov (United States)

    Kwak, Chung Shil; Moon, Sung Chae; Lee, Mee Sook

    2006-01-01

    Pine needles (Pinus densiflora Siebold et Zuccarini) have long been used as a traditional health-promoting medicinal food in Korea. To investigate their potential anticancer effects, antioxidant, antimutagenic, and antitumor activities were assessed in vitro and/or in vivo. Pine needle ethanol extract (PNE) significantly inhibited Fe(2+)-induced lipid peroxidation and scavenged 1,1-diphenyl- 2-picrylhydrazyl radical in vitro. PNE markedly inhibited mutagenicity of 2-anthramine, 2-nitrofluorene, or sodium azide in Salmonella typhimurium TA98 or TA100 in Ames tests. PNE exposure effectively inhibited the growth of cancer cells (MCF-7, SNU-638, and HL-60) compared with normal cell (HDF) in 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. In in vivo antitumor studies, freeze-dried pine needle powder supplemented (5%, wt/wt) diet was fed to mice inoculated with Sarcoma-180 cells or rats treated with mammary carcinogen, 7,12-dimethylbenz[a]anthracene (DMBA, 50 mg/kg body weight). Tumorigenesis was suppressed by pine needle supplementation in the two model systems. Moreover, blood urea nitrogen and aspartate aminotransferase levels were significantly lower in pine needle-supplemented rats in the DMBA-induced mammary tumor model. These results demonstrate that pine needles exhibit strong antioxidant, antimutagenic, and antiproliferative effects on cancer cells and also antitumor effects in vivo and point to their potential usefulness in cancer prevention.

  6. SILICON NEEDLE ARRAY ON FLEXIBLE SUBSTRATE FOR FLUID TRANSFER

    Institute of Scientific and Technical Information of China (English)

    MA Bin; GAN Zhiyin; LIU Sheng

    2006-01-01

    Transdermal delivery is an attractive alternative, but it is limited by the extremely low permeability of skin. To solve this problem, a novel means-micro needle array based on micro electro-mechanical system (MEMS) technology, is provided to increase permeability of human skin with efficiency, safety and painless delivery. The fabrication method consists of a sequence of deep-reactive ion etching (DRIE), anisotropic wet etching and conformal thin film deposition. The novel technology can enable the realization of micro fabricated micro needle array on a flexible silicon substrate. The micro needle array can be mounted on non-planar surface or even on flexible objects such as a human fingers and arms. The fabricated hollow wall straight micro needles are 200 μm in length, 30 μm inner diameter, and 50 μm outer diameter with 250 μm center-to-center spacing.Flow rate test proves that the polymeric base construction is important to function of micro needles array in package. Glucose solvent tests show that surface tension is the dominant force to affect the characters of flow in micro needles channel.

  7. Initial experience with new dedicated needles for laparoscopic ultrasound-guided fine-needle aspiration and histological biopsies

    DEFF Research Database (Denmark)

    Mortensen, M B; Durup, J; Pless, T;

    2001-01-01

    BACKGROUND AND STUDY AIMS: Laparoscopic ultrasonography (LUS) is an important imaging modality during laparoscopic staging of intra-abdominal malignancies, but LUS-assisted biopsy is often difficult or impossible. We report a newly developed inbuilt biopsy system for direct LUS-guided fine......-needle aspiration (FNA) and Tru-cut biopsies. PATIENTS AND METHODS: LUS-guided biopsy was performed in 20 patients with upper gastrointestinal tract tumors. The biopsied lesions had either not been previously detected by other imaging modalities or had been inaccessible, or the biopsy sample had been inadequate....... Primary diagnosis, duration of biopsy procedure, needle monitoring (visibility, penetration, and deviation), complications, technical failures, and pathological findings were prospectively recorded. RESULTS: 44 biopsies were performed with 25 needles (19, 20, and 22-G). Needle monitoring and penetration...

  8. A highly sensitive fiber Bragg grating diaphragm pressure transducer

    Science.gov (United States)

    Allwood, Gary; Wild, Graham; Lubansky, Alex; Hinckley, Steven

    2015-10-01

    In this work, a novel diaphragm based pressure transducer with high sensitivity is described, including the physical design structure, in-depth analysis of optical response to changes in pressure, and a discussion of practical implementation and limitations. A flat circular rubber membrane bonded to a cylinder forms the body of the transducer. A fiber Bragg grating bonded to the center of the diaphragm structure enables the fractional change in pressure to be determined by analyzing the change in Bragg wavelength of the reflected spectra. Extensive evaluation of the physical properties and optical characteristics of the transducer has been performed through experimentation, and modeling using small deformation theory. The results show the transducer has a sensitivity of 0.116 nm/kPa, across a range of 15 kPa. Ultra-low cost interrogation of the optical signal was achieved through the use of an optically mismatched Bragg grating acting as an edge filter to convert the spectral change into an intensity change. A numerical model of the intensity based interrogation was implemented in order to validate the experimental results. Utilizing this interrogation technique and housing both the sensing and reference Bragg gratings within the main body of the transducer means it is effectively temperature insensitive and easily connected to electronic systems.

  9. Delimitation of the lung region with distributed ultrasound transducers

    Science.gov (United States)

    Cardona Cárdenas, Diego Armando; Furuie, Sérgio Shiguemi

    2016-04-01

    One technique used to infer and monitor patient's respiratory conditions is the electrical impedance tomography (EIT). This provides images with information about lung function. The EIT image contrast is dependent on the variation of electrical impedance, therefore, this image does not provide anatomical details in border regions of several organs. To contribute to a clinical solution, we propose a new method to delimit regions of interest such as the pulmonary region and to improve the reconstruction quality of the EIT. Using a Matlab Toolbox k-wave, the ultrasound propagation phenomenon in homogeneous medium without patient (Reference) and with thoracic models were simulated, separately via a set of several ultrasound transducers distributed around the chest. After pulse emission by a transducer (TR), all received signals were compared considering the two sets of signals. If the energy relation between parts of the signals does not exceed an empirical threshold (30% in this study), a partial mask is generated between the transmitter and the receptor. This process was repeated until all 128 transducers are considered as TR-emitters. The 128 transducers (150kHz) are uniformly distributed. The evaluation was made by visually comparing the resulting images with the respective simulated object. A simple approach was presented to delimit high contrast organs with ultrasound transducers distributed around the patient. This approach allows other lower contrast objects to become invisible by varying the threshold limit. The investigation, based on numerical simulations of ultrasonic propagation, has shown promising results in the delimitation of the pulmonary region.

  10. A cylindrical standing wave ultrasonic motor using bending vibration transducer.

    Science.gov (United States)

    Liu, Yingxiang; Chen, Weishan; Liu, Junkao; Shi, Shengjun

    2011-07-01

    A cylindrical standing wave ultrasonic motor using bending vibration transducer was proposed in this paper. The proposed stator contains a cylinder and a bending vibration transducer. The two combining sites between the cylinder and the transducer locate at the adjacent wave loops of bending vibration of the transducer and have a distance that equal to the half wave length of bending standing wave excited in the cylinder. Thus, the bending mode of the cylinder can be excited by the bending vibration of the transducer. Two circular cone type rotors are pressed in contact to the end rims of the teeth, and the preload between the rotors and stator is accomplished by a spring and nut system. The working principle of the proposed motor was analyzed. The motion trajectories of teeth were deduced. The stator was designed and analyzed with FEM. A prototype motor was fabricated and measured. Typical output of the prototype is no-load speed of 165rpm and maximum torque of 0.45Nm at an exciting voltage of 200V(rms).

  11. Wideband Tonpilz Transducer with a Cavity Inside a Head Mass

    Science.gov (United States)

    Saosometh Chhith,; Yongrae Roh,

    2010-07-01

    A multimode Tonpilz transducer is well-known for providing a wider bandwidth than a single-mode transducer. In this paper, a new structure for the head mass of a multimode Tonpilz transducer was designed to further widen the bandwidth. The mechanical quality factor of a Tonpilz transducer is proportional to the weight of its head mass. In that sense, making the cavity inside the head mass will surely lead to a much lighter head mass, which can lead to a lower mechanical quality factor, thus a wider bandwidth. Through finite element analyses, the effects of the void head mass structure on the transducer performance were analyzed, and the dimension of the cavity to achieve the widest bandwidth was determined within given structural variation ranges. The variation ranges were selected as those in which the coefficient of determination in regression analyses was larger than 0.95 over all the ranges. The structure of a tail mass was also designed using the same method to match the new head mass.

  12. 1-3 Piezocomposite transducers for AUV applications

    Science.gov (United States)

    Pazol, Brian; Lannaman, Ken; Doust, Barry

    2001-05-01

    Sonar systems on board AUVs present interesting challenges to the transducer designer because of their small size, low weight requirements, and limited available power. 1-3 piezocomposite transducers offer many performance characteristics which make them ideal for deployment in AUVs. Piezocomposite transducers are light weight, have broad bandwidth, have high efficiency, and can be conformed to fit the curvature of the vehicle. The broad bandwidths and low sidelobes made possible by piezocomposites result in sharper images with less distortion. The piezocomposite material is mechanically robust and can survive the rigors of normal operations as well as AUV deployment and retrieval. In addition, the conformal configuration substantially reduces hydrodynamic drag. As a conformal array, there is nothing to get knocked off during deployment and retrieval operations, or entangled with natural or man-made objects suspended in the water column. This contributes directly to improving the operational endurance of the AUV system, thereby enhancing overall system utility. MSI has produced and tested a variety of piezocomposite transducers for use in obstacle avoidance, mine hunting, and acoustic communications. An overview of piezocomposites and recent results of piezocomposite transducers will be presented.

  13. Behavior of tip-steerable needles in ex vivo and in vivo tissue.

    Science.gov (United States)

    Majewicz, Ann; Marra, Steven P; van Vledder, Mark G; Lin, MingDe; Choti, Michael A; Song, Danny Y; Okamura, Allison M

    2012-10-01

    Robotic needle steering is a promising technique to improve the effectiveness of needle-based clinical procedures, such as biopsies and ablation, by computer-controlled, curved insertions of needles within solid organs. In this paper, we explore the capabilities, challenges, and clinical relevance of asymmetric-tip needle steering through experiments in ex vivo and in vivo tissue. We evaluate the repeatability of needle insertion in inhomogeneous biological tissue and compare ex vivo and in vivo needle curvature and insertion forces. Steerable needles curved more in kidney than in liver and prostate, likely due to differences in tissue properties. Pre-bent needles produced higher insertion forces in liver and more curvature in vivo than ex vivo. When compared to straight stainless steel needles, steerable needles did not cause a measurable increase in tissue damage and did not exert more force during insertion. The minimum radius of curvature achieved by prebent needles was 5.23 cm in ex vivo tissue, and 10.4 cm in in vivo tissue. The curvatures achieved by bevel tip needles were negligible for in vivo tissue. The minimum radius of curvature for bevel tip needles in ex vivo tissue was 16.4 cm; however, about half of the bevel tip needles had negligible curvatures. We also demonstrate a potential clinical application of needle steering by targeting and ablating overlapping regions of cadaveric canine liver.

  14. Comparison of two different size needles in endoscopic ultrasound-guided fine-needle aspiration for diagnosing solid pancreatic lesions

    Science.gov (United States)

    Xu, Mei-Mei; Jia, Hong-Yu; Yan, Li-Li; Li, Shan-Shan; Zheng, Yue

    2017-01-01

    Abstract Background: This meta-analysis aimed to provide a pooled analysis of prospective controlled trials comparing the diagnostic accuracy of 22-G and 25-G needles on endoscopic ultrasonography (EUS-FNA) of the solid pancreatic mass. Methods: We established a rigorous study protocol according to Cochrane Collaboration recommendations. We systematically searched the PubMed and Embase databases to identify articles to include in the meta-analysis. Sensitivity, specificity, and corresponding 95% confidence intervals were calculated for 22-G and 25-G needles of individual studies from the contingency tables. Results: Eleven prospective controlled trials included a total of 837 patients (412 with 22-G vs 425 with 25-G). Our outcomes revealed that 25-G needles (92% [95% CI, 89%–95%]) have higher sensitivity than 22-G needles (88% [95% CI, 84%–91%]) on solid pancreatic mass EUS-FNA (P = 0.046). However, there were no significant differences between the 2 groups in overall diagnostic specificity (P = 0.842). The pooled positive and negative likelihood ratio of the 22-G needle were 12.61 (95% CI, 5.65–28.14) and 0.16 (95% CI, 0.12–0.21), respectively. The pooled positive likelihood ratio was 12.61 (95% CI, 5.65–28.14), and the negative likelihood ratio was 0.16 (95% CI, 0.12–0.21) for the 22-G needle. The pooled positive likelihood ratio was 8.44 (95% CI, 3.87–18.42), and the negative likelihood ratio was 0.13 (95% CI, 0.09–0.18) for the 25-G needle. The area under the summary receiver operating characteristic curve was 0.97 for the 22-G needle and 0.96 for the 25-G needle. Conclusion: Compared to the study of 22-G EUS-FNA needles, our study showed that 25-G needles have superior sensitivity in the evaluation of solid pancreatic lesions by EUS–FNA. PMID:28151856

  15. Impact of Needle Diameter on Long-Term Dry Needling Treatment of Chronic Lumbar Myofascial Pain Syndrome

    Science.gov (United States)

    Wang, Gang; Gao, Qian; Li, Jun; Tian, Yuling; Hou, Jingshan

    2016-01-01

    ABSTRACT Objective To investigate the impact of diameter of needles on the effect of dry needling treatment of chronic lumbar myofascial pain syndrome. Design Forty-eight patients with chronic lumbar myofascial pain syndrome were randomly allocated to 3 groups. They received dry needling with needles of diameter 0.25 (group A), 0.5 (group B), and 0.9 mm (group C). Visual analog scale evaluation and health survey were conducted at baseline and 3 months after the treatment. Results Visual analog scale scores were significantly different in all groups from baseline to 3 months. Visual analog scale scores at 3 months showed differences between group C and the other 2 groups. When baseline and 3 months after treatment (0 day and 3 months) in each of the 3 groups was compared, there was a difference between group C and group B. The Short Form (36) Health Survey scores from baseline to 3 months were different within the treatment groups. Conclusions Visual analog scale score evaluations at 3 months showed efficacy in all groups. Results of 3 months showed that efficacy of treatment with larger needles (0.9-mm diameter) was better than that of smaller ones (0.5-mm diameter). The Short Form (36) Health Survey scores at 3 months indicated that treatments with needles of varying diameters were all effective, and when the results of 3 months were compared, there was no difference between the 3 groups. PMID:27333534

  16. 300 CASES OF HYPERPLASIA OF MAMMARY GLANDS TREATED WITH RED-HOT NEEDLE PLUS FILIFORM NEEDLE

    Institute of Scientific and Technical Information of China (English)

    蔡志红; 吴英; 付波; 贺普仁

    2003-01-01

    Clinical observations on 300 cases of hyperplasia of mammary glands (group A) treated by red-hot needle plus filiform needle are reported in the present study. "Ashi" points were used as the main acupoints. For comparison, other 300 cases (group B) were treated with routine acupuncture method, and Rugen (ST 18) was used as the main acupoint. In addition, other auxiliary acupoints were supplemented in the light of the concrete syndromes in these two groups. The treatment was given once daily, with 10 sessions being a therapeutic course. Of the 300 cases in group A, 240 were clinically cured, amounting to 80%; 58 were effective, amounting to 19.3%; 2 were failed, with a total effective rate of 99.3%. Of the 300 cases in group B, 113 were clinically cured, 165 effective, 22 were failed, with a total effective rate of 92.7%. The therapeutic effect of group A is significantly superior to that of group B (P<0.05).

  17. Reducing the Effect of Transducer Mount Induced Noise on Aeroacoustic Wind Tunnel Testing Data with a New Transducer Mount Design

    Science.gov (United States)

    Herron, A. J.; Reed, D. K.; Nance, D. K.

    2015-01-01

    Characterization of launch vehicle unsteady aerodynamics is a field best studied through experimentation, which is often carried out in the form of large scale wind tunnel testing. Measurement of the fluctuating pressures induced by the boundary layer noise is customarily made with miniature pressure transducers installed into a model of the vehicle of interest. Literature shows that noise level increases between two to five decibels (dB referenced to 20 micropascal) can be induced when the transducer surface is not mounted perfectly flush with the model outer surface. To reduce this artificially induced noise, special transducer holders have been used for aeroacoustic wind tunnel testing by NASA. This holder is a sleeve into which the transducer fits, with a cap that allows it to be mounted in a recessed hole in the model. A single hole in the holder allows the transport of the tunnel medium so the transducer can discriminate the fluctuating pressure due to the turbulent boundary layer noise. The holder is first dry fitted into the model and any difference in height between the holder and the model surface can be sanded flush. The holder is then removed from the model, the transducer glued inside the holder, and the holder replaced in the model, secured also with glue, thus eliminating the problem of noise level increases due to lack of flushness. In order to work with this holder design, special transducers have been ordered with their standard screen removed and the diaphragm moved as close to the top of the casing as possible to minimize any cavity volume. Although this greatly reduces induced noise due to the transducers being out of flush, the holders can also induce a cavity resonance that is usually at a very high frequency. This noise is termed transducer mount induced noise (XMIN). The peak of the mode can vary with the cavity depth, boundary layer noise that can excite the mode, tunnel flow medium, and the build of the transducers. Because the boundary

  18. Design, production and testing of PMN-PT electrostrictive transducers.

    Science.gov (United States)

    Coutte, J; Dubus, B; Debus, J C; Granger, C; Jones, D

    2002-05-01

    Lead magnesium niobate ceramics (PMN) are promising materials for application in the field of high power transducers. The advantage of PMN materials are the large strains generated under moderate electric field and the low hysteresis. The electrostrictive effect is non-linear, the corresponding physical constants depend on temperature and frequency and a DC electrical bias is required. These difficulties must be considered at the design stage. A finite element model has been developed and validated in the ATILA code for non-linear static and time-domain analyses. These numerical modelings are used to design and test two Langevin-type electrostrictive transducers. The first transducer is made of PMN-PT-La (90-10-1%) ceramics (TRS Ceramics), the second one of ESCI ceramics (Morgan Matroc). For given static mechanical prestresses, resonance frequencies and effective coupling coefficients are measured at different DC electric fields and temperatures.

  19. Energy harvesting with a slotted-cymbal transducer

    Institute of Scientific and Technical Information of China (English)

    Jiang-bo YUAN; Xiao-biao SHAN; Tao XIE; Wei-shan CHEN

    2009-01-01

    A cymbal transducer is made up of a piezoceramic disk sandwiched between two dome-shaped metal endcaps. High circumferential stresses caused by flexural motion of the metal endcaps can induce the loss of mechanical input energy. Finite element analysis shows that the radial slots fabricated in metal endcaps can release the circumferential stresses, and reduce the loss of mechanical input energy that could be converted into electrical energy. In this letter, the performance of a slotted-cymbal transducer in energy harvesting was tested. The results show that the output voltage and power of the cymbal are improved. A maximum output power of around 16 mW could be harvested from a cymbal with 18 cone radial slots across a 500kΩ resistive load, which is approximately 0.6 times more than that of the original cymbal transducer.

  20. Phased annular array transducers for ultrasonic guided wave applications

    Science.gov (United States)

    Yan, Fei; Borigo, Cody; Liang, Yue; Koduru, Jaya P.; Rose, Joseph L.

    2011-04-01

    Mode and frequency control always plays an important role in ultrasonic guided wave applications. In this paper, theoretical understanding of guided wave excitations of axisymmetric sources on plate structures is established. It is shown that a wave number spectrum can be used to investigate the guided wave excitations of an axisymmetric source. The wave number spectrum is calculated from a Hankel transform of the axial source loading profile. On the basis of the theoretical understanding, phased annular array transducers are developed as a powerful tool for guided wave mode and frequency control. By applying appropriate time delays to phase the multiple elements of an annular array transducer, guided wave mode and frequency tuning can be achieved fully electronically. The phased annular array transducers have been successfully used for various applications. Example applications presented in this paper include phased annular arrays for guided wave beamforming and a novel ultrasonic vibration modal analysis technique for damage detection.

  1. A novel serrated columnar phased array ultrasonic transducer

    Science.gov (United States)

    Zou, Cheng; Sun, Zhenguo; Cai, Dong; Song, Hongwei; Chen, Qiang

    2016-02-01

    Traditionally, wedges are required to generate transverse waves in a solid specimen and mechanical rotation device is needed for interrogation of a specimen with a hollow bore, such as high speed railway locomotive axles, turbine rotors, etc. In order to eliminate the mechanical rotation process, a novel array pattern of phased array ultrasonic transducers named as serrated columnar phased array ultrasonic transducer (SCPAUT) is designed. The elementary transducers are planar rectangular, located on the outside surface of a cylinder. This layout is aimed to generate electrically rotating transverse waveforms so as to inspect the longitudinal cracks on the outside surface of a specimen which has a hollow bore at the center, such as the high speed railway locomotive axles. The general geometry of the SCPAUT and the inspection system are illustrated. A FEM model and mockup experiment has been carried out. The experiment results are in good agreement with the FEM simulation results.

  2. Some design considerations for small piezo-electrical ceramic transducers

    Science.gov (United States)

    Rijnja, H. A. J.

    1989-07-01

    The design parameters and the characteristics of small omnidirectional transducers, to be applied under water as projectors in the frequency range of about 1 kHz to 100 kHz and as hydrophones from very low frequencies up to again 100kHz are described. The transducers are constructed with piezoelectrical ceramic materials in the shape of hollow spheres, end capped tubes or piston (Tonpilz) elements. The highest source levels are obtained with spherical transducers as single omnidirectional sound sources. If larger arrays of sources are applied the array should be composed of single ended Tonpilz elements. The most sensitive receivers (hydrophones) are obtained with tangentially polarized end-capped tubes.

  3. Finite element analysis of piezoelectric underwater transducers for acoustic characteristics

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jae Hwan [Inha University, Incheon (Korea, Republic of); Kim, Heung Soo [Catholic University, Daegu (Korea, Republic of)

    2009-02-15

    This paper presents a simulation technique for analyzing acoustic characteristics of piezoelectric underwater transducers. A finite element method is adopted for modeling piezoelectric coupled problems including material damping and fluid-structure interaction problems by taking system matrices in complex form. For the finite element modeling of unbounded acoustic fluid, infinite wave envelope element (IWEE) is adopted to take into account the infinite domain. An in-house finite element program is developed and technical issues for implementing the program are explained. Using the simulation program, acoustic characteristics of tonpilz transducer are analyzed in terms of modal analysis, radiated pressure distribution, pressure spectrum, transmitting-voltage response and impedance analysis along with experimental comparison. The developed simulation technique can be used for designing ultrasonic transducers in the areas of nondestructive evaluation, underwater acoustics and bioengineering

  4. Actuators, transducers and motors based on giant magnetostrictive materials

    Energy Technology Data Exchange (ETDEWEB)

    Claeyssen, F.; Lhermet, N.; Le Letty, R. [Cedrat Recherche, Meylan (France); Bouchilloux, P. [Magsoft Corporation, 1223 People`s Avenue, New York 12180 (United States)

    1997-08-01

    Rare earth-iron magnetostrictive alloys, especially Terfenol-D, feature ``giant`` magnetostrains: static strains of 1000-2000 ppm and dynamic strains of 3500 ppm are reported. These strains permit building various actuating devices (actuators, transducers, motors) both at macro and micro scale. The object of the paper is to recall adapted design methods, especially finite element methods such as ATILA, and to review these different kinds of devices studied at Cedrat Recherche, providing both up-dated experimental and numerical results. The presented devices will include several large displacement longitudinal and shear actuators biased using permanent magnets and used either as characterisation devices or as electromechanical actuators (for active damping, for sonar transducers..), a 1 kHz 4 kW Tonpilz-type sonar transducer called the tripode, a 2 N m torque rotating multi-mode motor, a torsion based drift free micro actuator and a wireless linear micromotor. (orig.)

  5. INFLUENCE OF PIEZOELECTRIC TRANSDUCER TO GLASS FIBER REINFORCED COMPOSITE STIFFNESS

    Directory of Open Access Journals (Sweden)

    Witold Rządkowski

    2015-08-01

    Full Text Available The main goal was to determine if transducers based on piezoelectric materials are suitable for strain calculations in thin GFRP specimens. Numerous experimental studies, both physical and numerical, performed by the authors, have shown that there is a huge influence of bonded piezoelectric transducer on the overall stiffness of the measured object. The paper presents tensile test performed on strength machine with Digital Image Correlation strain and deflection observations. Test were compared with FEM models for detailed investigation. The main conclusion is piezoelectric transducers has huge influence on local stiffness of measured object. That is critical especially when they are used as strain sensors, when presence of sensor is influencing to measured results.

  6. Fine needle aspiration biopsy of fibromatoses.

    Science.gov (United States)

    Raab, S S; Silverman, J F; McLeod, D L; Benning, T L; Geisinger, K R

    1993-01-01

    Fibromatoses form a spectrum of clinicopathologic entities characterized by the infiltrative proliferation of fibroblasts that lack malignant cytologic features. Fibromatoses present as nodular soft tissue masses almost anywhere in the body and thus are often amenable to fine needle aspiration (FNA). This report describes the FNA cytologic findings of fibromatosis in six patients ranging in age from 7 1/2 weeks to 36 years. Two of the lesions arose in the abdominal wall (musculoaponeurotic fibromatosis or extra-abdominal desmoid), and one each involved the plantar surface (Ledderhose's disease), the shoulder and the sternocleidomastoid muscle (Fibromatosis coli). The FNA of the shoulder was initially interpreted as nodular fasciitis due to the clinical presentation of a rapidly growing mass; an aspirate from the deep musculoaponeurotic region was believed to reveal a low grade sarcoma. The FNA diagnosis of musculoaponeurotic fibromatosis in a patient with familial polyposis coli suggested the diagnosis of Gardner's syndrome. Cytologically the aspirates consisted of groups of loosely cohesive, bland-appearing, spindle-shaped cells having oval to elongated nuclei and cytoplasmic tags. Individual spindle cells and rare inflammatory cells were also present. The aspirate of fibromatosis coli also contained degenerating skeletal muscle cells. Tissue confirmation was obtained in four cases. We believe that FNA is a useful procedure for the initial and recurrent diagnosis of fibromatoses and in the separation of fibromatoses from other benign and malignant soft tissue lesions. A discussion of other entities that enter into the cytologic differential diagnosis, such as mesenchymal repair, fasciitis and spindle cell types of sarcoma, is presented. From our experience we believe that the clinicopathologic features can suggest the diagnosis of fibromatosis, but histologic confirmation is recommended.

  7. High intensity ultrasound transducer used in gene transfection

    Science.gov (United States)

    Morrison, Kyle P.; Keilman, George W.; Noble, Misty L.; Brayman, Andrew A.; Miao, Carol H.

    2012-11-01

    This paper describes a novel therapeutic high intensity non-focused ultrasound (HIU) transducer designed with uniform pressure distribution to aid in accelerated gene transfer in large animal liver tissues in vivo. The underlying HIU transducer was used to initiate homogeneous cavitation throughout the tissue while delivering up to 2.7 MPa at 1.1 MHz across its radiating surface. The HIU transducer was built into a 6 cm diameter x 1.3 cm tall housing ergonomically designed to avoid collateral damage to the surrounding anatomy during dynamic motion. The ultrasound (US) radiation was applied in a 'paintbrush-like' manner to the surface of the liver. The layers and geometry of the transducer were carefully selected to maximize the active diameter (5.74 cm), maximize the electrical to acoustic conversion efficiency (85%) to achieve 2.7 MPa of peak negative pressure, maximize the frequency operating band at the fundamental resonance to within a power transfer delta of 1 dB, and reduce the pressure delta to within 2 dB across the radiating surface. For maximum peak voltage into the transducer, a high performance piezoceramic was chosen and a DC bias circuit was built integral to the system. An apodized two element annular pattern was made from a single piezoceramic element, resulting in significant pressure uniformity enhancement. In addition to using apodization for pressure uniformity, a proprietary multi-layered structure was used to improve efficiency while sustaining an operating band from 900 kHz to 1.3 MHz. The resultant operating band allowed for dithering techniques using frequency modulation. The underlying HIU transducer for use in large animals enhances gene expression up to 6300-fold.

  8. Sensory TRP channels: the key transducers of nociception and pain.

    Science.gov (United States)

    Mickle, Aaron D; Shepherd, Andrew J; Mohapatra, Durga P

    2015-01-01

    Peripheral detection of nociceptive and painful stimuli by sensory neurons involves a complex repertoire of molecular detectors and/or transducers on distinct subsets of nerve fibers. The majority of such molecular detectors/transducers belong to the transient receptor potential (TRP) family of cation channels, which comprise both specific receptors for distinct nociceptive stimuli, as well as for multiple stimuli. This chapter discusses the classification, distribution, and functional properties of individual TRP channel types that have been implicated in various nociceptive and/or painful conditions.

  9. The planar silicon-based microelectronic technology for electrochemical transducers

    Science.gov (United States)

    Novikov, A. V.; Egorchikov, A. E.; Dolgov, A. N.; Gornev, E. S.; Popov, V. G.; Egorov, I. V.; Krishtop, V. G.

    2016-12-01

    We have developed the new technology for production of sensitive modules for electrochemical sensors of pressure and acceleration. The technology is applicable for mass production and scalable for high-volume production. In this work we demonstrate the new sensing module for electrochemical motion sensors, and its possibility of applying in geophones. We fabricated prototypes of electrochemical planar transducer chips, produced a laboratory prototype of a geophone based on our planar transducer chip, and tested them. This paper presents the preliminary results of the tests.

  10. Simulating Capacitive Micromachined Ultrasonic Transducers (CMUTs) using Field II

    DEFF Research Database (Denmark)

    Bæk, David; Oralkan, Omer; Kupnik, Mario;

    2010-01-01

    Field II has been a recognized simulation tool for piezoceramic medical transducer arrays for more than a decade. The program has its strength in doing fast computations of the spatial impulse response (SIR) from array elements by dividing the elements into smaller mathematical elements (ME)s from...... which it calculates the SIR responses. The program features predefined models for classical transducer geometries, but currently none for the fast advancing CMUTs. This work addresses the assumptions required for modeling CMUTs with Field II. It is shown that rectangular array elements, populated...

  11. General Situation on Clinical Application of Dragon-Tiger Fighting Needling Technique in the Recent Years

    Institute of Scientific and Technical Information of China (English)

    何龙; 袁宜勤; 钟耀东; 何贤发; 黄国琪

    2008-01-01

    @@ Depending upon the descriptions of the ancient literature, such as Jin Zhen Fu (Odes to Golden Needles, ), the dragon-tiger fighting needling technique has the effects to dredge the meridians, circulate qi, activate blood, stop and remove pain. "Dragon" implies to twist the needle leftward for reinforcing, and "tiger" means to twist the needle rightward for reducing. To twist the needle leftward and rightward alternately is termed "fighting". After the arrival of the needling sensation by inserting the needle to the proper depth, the needle is first twisted leftward with the thumb forward in a method of nine yang numbers, and then twisted backward and rightward with the thumb backward in a method of six yin numbers, in alternation of reinforcing and reducing repeatedly. Therefore, the general information on clinical application of dragon-tiger fighting needling technique in the recent sixteen years is given in the following.

  12. Fusion of electromagnetic trackers to improve needle deflection estimation: simulation study.

    Science.gov (United States)

    Sadjadi, Hossein; Hashtrudi-Zaad, Keyvan; Fichtinger, Gabor

    2013-10-01

    We present a needle deflection estimation method to anticipate needle bending during insertion into deformable tissue. Using limited additional sensory information, our approach reduces the estimation error caused by uncertainties inherent in the conventional needle deflection estimation methods. We use Kalman filters to combine a kinematic needle deflection model with the position measurements of the base and the tip of the needle taken by electromagnetic (EM) trackers. One EM tracker is installed on the needle base and estimates the needle tip position indirectly using the kinematic needle deflection model. Another EM tracker is installed on the needle tip and estimates the needle tip position through direct, but noisy measurements. Kalman filters are then employed to fuse these two estimates in real time and provide a reliable estimate of the needle tip position, with reduced variance in the estimation error. We implemented this method to compensate for needle deflection during simulated needle insertions and performed sensitivity analysis for various conditions. At an insertion depth of 150 mm, we observed needle tip estimation error reductions in the range of 28% (from 1.8 to 1.3 mm) to 74% (from 4.8 to 1.2 mm), which demonstrates the effectiveness of our method, offering a clinically practical solution.

  13. Needle localization of small pediatric tumors for surgical biopsy

    Energy Technology Data Exchange (ETDEWEB)

    Hardaway, B.W.; Hoffer, F.A. [Dept. of Diagnostic Imaging, St. Jude Children' s Research Hospital, Memphis, TN (United States); Rao, B.N. [Dept. of Surgery, St. Jude Children' s Research Hospital, Memphis Tennessee (United States)

    2000-05-01

    Background. Small pediatric tumors may be difficult to biopsy or resect. Objective. To examine the benefits of needle localization of a variety of small pediatric tumors before surgical biopsy or excision. Materials and methods. Seven patients aged 1-19 years underwent 12 procedures for needle localization of suspected tumor. Two patients had undergone previous biopsies without needle localization with negative results. Computed tomography (four patients) or ultrasonography (three patients) guided needle placement. Each patient had suspected tumor(s) in 1-3 anatomical sites, including thigh (7), lung (2), parasacral region (2), and iliac bone (1). Results. All 12 lesions (9 less than 1 cm{sup 3} in volume) were successfully localized for excision or biopsy. Three small (<1 cm{sup 3}) soft-tissue lesions (two ganglioneuroblastomas and one ganglioneuroma) were excised from one patient, a 0.65-cm{sup 3} residual soft-tissue sarcoma from another; and recurrent bilateral teratomas from a third. Two peripheral primitive neuroectodermal tumors were excised with positive margins from a fourth patient. Two lesions contained only fibrosis, as determined by histopathology. Two other patients underwent thoracoscopic removal of lung metastases that were less than 0.1 cm{sup 3}. Conclusion. Needle localization allows effective and less invasive excision or biopsy of a variety of small pediatric soft-tissue lesions. (orig.)

  14. Biopsy Needle Localization and Tracking Using ROI-RK Method

    Directory of Open Access Journals (Sweden)

    Yue Zhao

    2014-01-01

    Full Text Available ROI-RK method is a biopsy needle localization and tracking method. Previous research work has proved that it has a robust performance on different series of simulated 3D US volumes. Unfortunately, in real situations, because of the strong speckle noise of the ultrasound image and the different echogenic properties of the tissues, the real 3D US volumes have more complex background than the simulated images used previously. In this paper, to adapt the ROI-RK method in real 3D US volumes, a line-filter enhancement calculation only in the ROI is added to increase the contrast between the needle and background tissue, decreasing the phenomenon of expansion of the biopsy needle due to reverberation of ultrasound in the needle. To make the ROI-RK method more stable, a self-correction system is also implemented. Real data have been acquired on an ex vivo heart of lamb. The result of the ROI-RK method shows that it is capable to localize and track the biopsy needle in real situations, and it satisfies the demand of real-time application.

  15. Development of Needle Insertion Manipulator for Central Venous Catheterization

    Science.gov (United States)

    Kobayashi, Yo; Hong, Jaesung; Hamano, Ryutaro; Hashizume, Makoto; Okada, Kaoru; Fujie, Masakatsu G.

    Central venous catheterization is a procedure, which a doctor insert a catheter into the patient’s vein for transfusion. Since there are risks of bleeding from arterial puncture or pneumothorax from pleural puncture. Physicians are strictly required to make needle reach up into the vein and to stop the needle in the middle of vein. We proposed a robot system for assisting the venous puncture, which can relieve the difficulties in conventional procedure, and the risks of complication. This paper reports the design structuring and experimental results of needle insertion manipulator. First, we investigated the relationship between insertion force and angle into the vein. The results indicated that the judgment of perforation using the reaction force is possible in case where the needling angle is from 10 to 20 degree. The experiment to evaluate accuracy of the robot also revealed that it has beyond 0.5 mm accuracy. We also evaluated the positioning accuracy in the ultrasound images. The results displays that the accuracy is beyond 1.0 mm and it has enough for venous puncture. We also carried out the venous puncture experiment to the phantom and confirm our manipulator realized to make needle reach up into the vein.

  16. An allelopathic substance in red pine needles (Pinus densiflora).

    Science.gov (United States)

    Kato-Noguchi, Hisashi; Fushimi, Yoshiko; Shigemori, Hideyuki

    2009-03-01

    Aqueous methanol extracts of red pine (Pinus densiflora) needles inhibited the growth of roots and shoots of cress (Lepidium sativum), lettuce (Lactuca sativa), alfalfa (Medicago sativa), ryegrass (Lolium multiflorum), timothy (Pheleum pratense), Digitaria sanguinalis and Echinochloa crus-galli. Increasing the extract concentration increased inhibition, suggesting that the pine needles may have growth inhibitory substances and possess allelopathic potential. The aqueous methanol extract of the pine needles was purified, and a main inhibitory substance was isolated and determined by spectral data as 9alpha,13beta-epidioxyabeit-8(14)en-18-oic acid. This substance inhibited root and shoot growth of cress and Echinochloa crus-galli seedlings at concentrations greater than 0.1 mM. The endogenous concentration of the substance was 0.13 mmol/kg pine needle. These results suggest that 9alpha,13beta-epidioxyabeit-8(14)en-18-oic acid may contribute to the growth inhibitory effect of the pine needles and may play an important role in the allelopathy of red pine.

  17. Laryngeal chondrosarcoma diagnosed by core-needle biopsy.

    Science.gov (United States)

    Miyamaru, Satoru; Haba, Koichi

    2014-01-01

    We report a case of chondrosarcoma of the larynx, diagnosed by a percutaneous core-needle biopsy (CNB). Cartilaginous tumors of the larynx are usually diagnosed by biopsy with direct laryngomicroscopy under general anesthesia. However, patients find it difficult to undergo a biopsy under general anesthesia, for physical, economic, and social reasons. Instead, we can readily detect and sample tumors of the larynx using ultrasound under local anesthesia with reduced stress. Concerning needle-puncture biopsies, including fine-needle aspiration cytology (FNAC) and CNB, some studies have reported needle track dissemination, a possible complication in patients with malignant tumors. Thus, in the head and neck region, we generally use FNAC for biopsies, not CNB. However, it can be difficult to diagnose bone tumors by cytology alone. Regarding primary bone tumors, only one study has reported needle track dissemination by CNB, in osteosarcoma of the femur. Additionally, this complication has not been reported before with chondrosarcoma anywhere in the body. To our knowledge, this is the first report concerning chondrosarcoma of the larynx diagnosed by percutaneous CNB. We recommend CNB as a useful and safe diagnostic technique for primary bone tumors in the head and neck region.

  18. Single Crystal Diamond Needle as Point Electron Source

    Science.gov (United States)

    Kleshch, Victor I.; Purcell, Stephen T.; Obraztsov, Alexander N.

    2016-10-01

    Diamond has been considered to be one of the most attractive materials for cold-cathode applications during past two decades. However, its real application is hampered by the necessity to provide appropriate amount and transport of electrons to emitter surface which is usually achieved by using nanometer size or highly defective crystallites having much lower physical characteristics than the ideal diamond. Here, for the first time the use of single crystal diamond emitter with high aspect ratio as a point electron source is reported. Single crystal diamond needles were obtained by selective oxidation of polycrystalline diamond films produced by plasma enhanced chemical vapor deposition. Field emission currents and total electron energy distributions were measured for individual diamond needles as functions of extraction voltage and temperature. The needles demonstrate current saturation phenomenon and sensitivity of emission to temperature. The analysis of the voltage drops measured via electron energy analyzer shows that the conduction is provided by the surface of the diamond needles and is governed by Poole-Frenkel transport mechanism with characteristic trap energy of 0.2-0.3 eV. The temperature-sensitive FE characteristics of the diamond needles are of great interest for production of the point electron beam sources and sensors for vacuum electronics.

  19. Analysis of eigenfrequencies in piezoelectric transducers using the finite element method

    DEFF Research Database (Denmark)

    Jensen, Henrik

    1988-01-01

    It is noted that the finite-element method is a valuable supplement to the traditional methods for design of novel transducer types because it can determine the vibrational pattern of piezoelectric transducers and is applicable to any geometry. Computer programs for analysis of axisymmetric...... transducers, which include the complete set of piezoelectric equations, have been included. They can find eigenfrequencies for undamped transducers and perform forced-response analysis for transducers with internal and radiation damping. The superelement technique is used to model the transducer backing...

  20. NPIP: A skew line needle configuration optimization system for HDR brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Siauw, Timmy; Cunha, Adam; Berenson, Dmitry; Atamtuerk, Alper; Hsu, I-Chow; Goldberg, Ken; Pouliot, Jean [Department of Civil and Environmental Engineering, University of California, Berkeley, 760 Davis Hall, Berkeley, California 94720-1710 (United States); Department of Radiation Oncology, University of California, San Francisco, Comprehensive Cancer Center, 1600 Divisadero Street, Suite H1031, San Francisco, California 94143-1708 (United States); Department of Electrical Engineering and Computer Science, University of California, Berkeley, 4th Floor Sutardja Dai Hall, Berkeley, California 94720-1764 (United States); Department of Industrial Engineering and Operations, University of California, Berkeley, 4141 Etcheverry Hall, Berkeley, California 94720-1777 (United States); Department of Radiation Oncology, University of California, San Francisco, Comprehensive Cancer Center, 1600 Divisadero Street, Suite H1031, San Francisco, California 94143-1708 (United States); Department of Industrial Engineering and Operations Research and Department of Electrical Engineering and Computer Science, University of California, Berkeley, 4141 Etcheverry Hall, Berkeley, California 94720-1777 (United States); Department of Radiation Oncology, University of California, San Francisco, Comprehensive Cancer Center, 1600 Divisadero Street, Suite H1031, San Francisco, California 94143-1708 (United States)

    2012-07-15

    Purpose: In this study, the authors introduce skew line needle configurations for high dose rate (HDR) brachytherapy and needle planning by integer program (NPIP), a computational method for generating these configurations. NPIP generates needle configurations that are specific to the anatomy of the patient, avoid critical structures near the penile bulb and other healthy structures, and avoid needle collisions inside the body. Methods: NPIP consisted of three major components: a method for generating a set of candidate needles, a needle selection component that chose a candidate needle subset to be inserted, and a dose planner for verifying that the final needle configuration could meet dose objectives. NPIP was used to compute needle configurations for prostate cancer data sets from patients previously treated at our clinic. NPIP took two user-parameters: a number of candidate needles, and needle coverage radius, {delta}. The candidate needle set consisted of 5000 needles, and a range of {delta} values was used to compute different needle configurations for each patient. Dose plans were computed for each needle configuration. The number of needles generated and dosimetry were analyzed and compared to the physician implant. Results: NPIP computed at least one needle configuration for every patient that met dose objectives, avoided healthy structures and needle collisions, and used as many or fewer needles than standard practice. These needle configurations corresponded to a narrow range of {delta} values, which could be used as default values if this system is used in practice. The average end-to-end runtime for this implementation of NPIP was 286 s, but there was a wide variation from case to case. Conclusions: The authors have shown that NPIP can automatically generate skew line needle configurations with the aforementioned properties, and that given the correct input parameters, NPIP can generate needle configurations which meet dose objectives and use as many

  1. Acupuncture needles and the Seebeck effect: do temperature gradients produce electrostimulation?

    Science.gov (United States)

    Cohen, M; Kwok, G; Cosic, I

    1997-01-01

    Acupuncture may act through modifying bioelectric events and this may occur through different mechanisms including the application of external currents. According to the Seebeck effect which produces a potential difference when a temperature gradient is placed across a conductor, the physical properties of acupuncture needles may produce internal currents due to the temperature gradient across the needle when placed insitu. Such currents were detected when needles were differentially heated and these currents were found to be in the range capable of producing biological effects. The traditional design of acupuncture needles and traditional needle manipulations seem to maintain a temperature gradient across the needle and thus enhance the Seebeck effect.

  2. Interdigitated interdigital transducer for surface elastometry of soft damping tissue.

    Science.gov (United States)

    Danicki, Eugene; Nowicki, Andrzej; Tasinkevych, Yuriy

    2013-06-01

    Measurement of the shear elastic constant of soft and highly damping tissue of high Poisson ratio is quite a challenging task. It is proposed to evaluate shear wave velocity and damping of tissue by measuring the shear skimming bulk waves using one interdigitated interdigital transducer on a piezoelectric layer, such as polyvinylidene fluoride, applied to the surface of the small tissue sample.

  3. Cantilever deflection measurement and actuation by an nterdigitated transducer

    NARCIS (Netherlands)

    Strambini, E.; Piazza, V.; Pingue, P.; Biasiol, G.; Sorba, L.; Beltram, F.

    2010-01-01

    A scheme that allows all-electrical high-bandwidth readout of a cantilever deflection by means of an integrated interdigitated transducer is presented. The present approach takes advantage of the piezoelectricity of the chosen cantilever substrate material to generate and detect surface-acoustic-wav

  4. Cooling method prolongs life of hot-wire transducer

    Science.gov (United States)

    Baldwin, L. V.; Sandborn, V. A.

    1964-01-01

    To cool a hot-wire transducer, the two ends of the wire are supported on thermally and electrically conductive rods, surrounded by a fluid cooling medium. By keeping the supporting rods at a substantially constant temperature, the probe is prevented from overheating.

  5. Two methods for absolute calibration of dynamic pressure transducers

    Science.gov (United States)

    Swift, G. W.; Migliori, A.; Garrett, S. L.; Wheatley, J. C.

    1982-12-01

    Two techniques are described for absolute calibration of a dynamic pressure transducer from 0 to 400 Hz in 1-MPa helium gas. One technique is based on a comparison to a mercury manometer; the other is based on the principle of reciprocity. The two techniques agree within the instrumental uncertainties of 1%.

  6. Nonlinear Dynamic Modeling of Langevin-Type Piezoelectric Transducers

    Directory of Open Access Journals (Sweden)

    Nicolás Peréz Alvarez

    2015-11-01

    Full Text Available Langevin transducers are employed in several applications, such as power ultrasound systems, naval hydrophones, and high-displacement actuators. Nonlinear effects can influence their performance, especially at high vibration amplitude levels. These nonlinear effects produce variations in the resonant frequency, harmonics of the excitation frequency, in addition to loss of symmetry in the frequency response and “frequency domain hysteresis”. In this context, this paper presents a simplified nonlinear dynamic model of power ultrasound transducers requiring only two parameters for simulating the most relevant nonlinear effects. One parameter reproduces the changes in the resonance frequency and the other introduces the dependence of the frequency response on the history of the system. The piezoelectric constitutive equations are extended by a linear dependence of the elastic constant on the mechanical displacement amplitude. For introducing the frequency hysteresis, the elastic constant is computed by combining the current value of the mechanical amplitude with the previous state amplitude. The model developed in this work is applied for predicting the dynamic responses of a 26 kHz ultrasonic transducer. The comparison of theoretical and experimental responses, obtained at several input voltages around the tuned frequency, shows a good agreement, indicating that the model can accurately describe the transducer nonlinear behavior.

  7. A distributed transducer system for functional electrical stimulation

    DEFF Research Database (Denmark)

    Gudnason, Gunnar; Nielsen, Jannik Hammel; Bruun, Erik

    2001-01-01

    Implanted transducers for functional electrical stimulation (FES) powered by inductive links are subject to conflicting requirements arising from low link efficiency, a low power budget and the need for protection of the weak signals against strong RF electromagnetic fields. We propose a solution...

  8. Multilevel inverter based class D audio amplifier for capacitive transducers

    DEFF Research Database (Denmark)

    Nielsen, Dennis; Knott, Arnold; Andersen, Michael A. E.

    2014-01-01

    The reduced semiconductor voltage stress makes the multilevel inverters especially interesting, when driving capacitive transducers for audio applications. A ± 300 V flying capacitor class D audio amplifier driving a 100 nF load in the midrange region of 0.1-3.5 kHz with Total Harmonic Distortion...

  9. Physical and chemical sensing using monolithic semiconductor optical transducers

    Science.gov (United States)

    Zappe, Hans P.; Hofstetter, Daniel; Maisenhoelder, Bernd; Moser, Michael; Riel, Peter; Kunz, Rino E.

    1997-09-01

    We present two monolithically integrated optical sensor systems based on semiconductor photonic integrated circuits. These compact, robust and highly functional transducers perform all necessary optical and electro-optical functions on-chip; extension to multi-sensor arrays is easily envisaged. A monolithic Michelson interferometer for high-resolution displacement measurement and a monolithic Mach-Zehnder interferometer for refractometry are discussed.

  10. Class D audio amplifiers for high voltage capacitive transducers

    DEFF Research Database (Denmark)

    Nielsen, Dennis

    with a large volume of the loudspeaker enclosure. Piezoelectric loudspeakers suffers from the poor power handling capability of the piezoelectric ceramic. However a niche is found in the market of hydrophones, because of the excellent impedance matching between the piezoelectric transducer and water...

  11. Enhancing endosomal escape of transduced proteins by photochemical internalisation.

    Directory of Open Access Journals (Sweden)

    Kevin Mellert

    Full Text Available Induced internalisation of functional proteins into cultured cells has become an important aspect in a rising number of in vitro and in vivo assays. The endo-lysosomal entrapment of the transduced proteins remains the major problem in all transduction protocols. In this study we compared the efficiency, cytotoxicity and protein targeting of different commercially available transduction reagents by transducing a well-studied fluorescently labelled protein (Atto488-bovine serum albumin into cultured human sarcoma cells. The amount of internalised protein and toxicity differed between the different reagents, but the percentage of transduced cells was consistently high. Furthermore, in all protocols the signals of the transduced Atto488-BSA were predominantly punctual consistent with an endosomal localisation. To overcome the endosomal entrapment, the transduction protocols were combined with a photochemical internalisation (PCI treatment. Using this combination revealed that an endosomal disruption is highly effective in cell penetrating peptide (CPP mediated transduction, whereas lipid-mediated transductions lead to a lower signal spreading throughout the cytosol. No change in the signal distribution could be achieved in treatments using non-lipid polymers as a transduction reagent. Therefore, the combination of protein transduction protocols based on CPPs with the endosomolytic treatment PCI can facilitate protein transduction experiments in vitro.

  12. A Novel Rotary Piezoelectric Motor Using First Bending Hybrid Transducers

    Directory of Open Access Journals (Sweden)

    Yingxiang Liu

    2015-08-01

    Full Text Available We report a novel rotary piezoelectric motor using bending transducers in this work. Three transducers are used to drive a disk-shaped rotor together by the elliptical movements of their driving tips; these motions are produced by the hybrid of two first bending vibration modes. The proposed piezoelectric transducer has a simple structure as it only contains an aluminum alloy beam and four pieces of PZT plates. Symmetrical structure is the only necessary condition in the design process as it will ensure the resonance frequencies of the two orthogonal first bending modes are equal. Transducers with first bending resonance frequency of about 53 kHz were fabricated and assembled into a rotary motor. The proposed motor exhibits good performance on speed and torque control. Under a working frequency of 53.2 kHz, the maximum no-load speed and the maximum torque of the prototype are tested to be 53.3 rpm and of 27 mN·m.

  13. Multilayer piezoelectric transducer models combined with Field II

    DEFF Research Database (Denmark)

    Bæk, David; Willatzen, Morten; Jensen, Jørgen Arendt

    2012-01-01

    One-dimensional and three-dimensional axisymmetric transducer model have been compared to determine their feasibility to predict the volt-to-surface impulse response of a circular Pz27 piezoceramic disc. The ceramic is assumed mounted with silver electrodes, bounded at the outer circular boundary...

  14. Investigation of capacitively coupled ultrasonic transducer system for nondestructive evaluation.

    Science.gov (United States)

    Zhong, Cheng Huan; Wilcox, Paul D; Croxford, Anthony J

    2013-12-01

    Capacitive coupling offers a simple solution to wirelessly probe ultrasonic transducers. This paper investigates the theory, feasibility, and optimization of such a capacitively coupled transducer system (CCTS) in the context of nondestructive evaluation (NDE) applications. The noncontact interface relies on an electric field formed between four metal plates-two plates are physically connected to the electrodes of a transducer, the other two are in a separate probing unit connected to the transmit/receive channel of the instrumentation. The complete system is modeled as an electric network with the measured impedance of a bonded piezoelectric ceramic disc representing a transducer attached to an arbitrary solid substrate. A transmission line model is developed which is a function of the physical parameters of the capacitively coupled system, such as the permittivity of the material between the plates, the size of the metal plates, and their relative positions. This model provides immediate prediction of electric input impedance, pulse-echo response, and the effect of plate misalignment. The model has been validated experimentally and has enabled optimization of the various parameters. It is shown that placing a tuning inductor and series resistor on the transmitting side of the circuit can significantly improve the system performance in terms of the signal-to-crosstalk ratio. Practically, bulk-wave CCTSs have been built and demonstrated for underwater and through-composite testing. It has been found that electrical conduction in the media between the plates limits their applications.

  15. Inductively coupled transducer system for damage detection in composites

    Science.gov (United States)

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

    2012-04-01

    The laminated construction of composite offers the possibility of permanently embedding sensors into structure, for example, ultrasonic transducers which can be used for NDE applications. An attractive and simple solution for probing embedded sensors wirelessly is via inductive coupling. However, before this can be achieved it is necessary to have a full understanding and proper design strategy for the inductively coupled system. This paper presents the developments of both system design procedure and a computer program for one dimensional inductively coupled transducer system mounted on a solid substrate. The design strategy in this paper mainly focuses on issues of localization of transducers, and optimizing the signal to noise level. Starting from a three coil equivalent circuit, this paper also explains how the measured impedance of a bonded piezoelectric disc is implemented into the system model representing a transducer bonded to an arbitrary solid substrate. The computer programme using this model provides immediate predictions of electrical input impedance, acoustic response and pulse-echo response. A series of experiments and calculations have been performed in order to validate the model. This has enabled the degree of accuracy required for various parameters within the model, such as mutual inductance between the coils and self-inductance of coils, to be assessed. Once validated, the model can be used as a tool to predict the effect of physical parameters, such as distance, lateral misalignment between the coils, and the coil geometry on the performance of an inductively coupled system.

  16. High Temperature Ultrasonic Transducers : Material Selection and Testing

    Science.gov (United States)

    Bar-Cohen, Yoseph; Bruno, Alessandro

    2012-01-01

    The task of my two-months internship was to test different materials to be used to build an high temperature transducer, to develop some prototypes and to test their performance, to assess the reliability of commercial product rated for such a temperature, as well as to collaborate in developing the signal processing code to measure the condensed water levels.

  17. Characterization of HIFU transducers designed for sonochemistry application: Acoustic streaming.

    Science.gov (United States)

    Hallez, L; Touyeras, F; Hihn, J-Y; Bailly, Y

    2016-03-01

    Cavitation distribution in a High Intensity Focused Ultrasound sonoreactors (HIFU) has been extensively described in the recent literature, including quantification by an optical method (Sonochemiluminescence SCL). The present paper provides complementary measurements through the study of acoustic streaming generated by the same kind of HIFU transducers. To this end, results of mass transfer measurements (electrodiffusional method) were compared to optical method ones (Particle Image Velocimetry). This last one was used in various configurations: with or without an electrode in the acoustic field in order to have the same perturbation of the wave propagation. Results show that the maximum velocity is not located at the focal but shifted near the transducer, and that this shift is greater for high powers. The two cavitation modes (stationary and moving bubbles) are greatly affect the hydrodynamic behavior of our sonoreactors: acoustic streaming and the fluid generated by bubble motion. The results obtained by electrochemical measurements show the same low hydrodynamic activity in the transducer vicinity, the same shift of the active focal toward the transducer, and the same absence of activity in the post-focal axial zone. The comparison with theoretical Eckart's velocities (acoustic streaming in non-cavitating media) confirms a very high activity at the "sonochemical focal", accounted for by wave distortion, which induced greater absorption coefficients. Moreover, the equivalent liquid velocities are one order of magnitude larger than the ones measured by PIV, confirming the enhancement of mass transfer by bubbles oscillation and collapse close to the surface, rather than from a pure streaming effect.

  18. Trajectory generation for robotic needle insertion in soft tissue.

    Science.gov (United States)

    Abolhassani, Niki; Patel, Rajni; Moallem, Mehrdad

    2004-01-01

    Accurate needle insertion in soft, inhomogeneous tissue has been a major concern in several recent studies involving robot-assisted percutaneous therapies. In procedures that involve multiple needle insertions such as transrectal ultrasound guided prostate brachytherapy, it is important to reduce tissue deformation before puncture and during insertion. In order to reduce this deformation, we have studied the effect of different trajectories for a 2-DOF robot performing needle insertion in soft tissue. We have compared tissue deformation and infinitesimal force per tissue displacement for different trajectories. According to the results of our experiments, infinitesimal force per displacement is a useful parameter for online trajectory update. Our proposed position/force controller is shown to provide considerable improvement in performance with regard to tissue deformation before puncture.

  19. Chondromalacia Patellae Treated by Warming Needle and Rehabilitation Training

    Institute of Scientific and Technical Information of China (English)

    QIU Ling; ZHANG Min; ZHANG Ji; GAO Le-nv; CHEN Da-wei; LIU Jun; SHE Jia-yi; WANG Ling; YU Jin-yan; HUANG Le-ping; BAI Yang

    2009-01-01

    Objective:To observe the effect of wanning needle combined with rehabilitation training on chondromalacia patellae in a randomized controlled trial. Methods: The 92 cases were randomly divided into a treatment group treated by warming needle plus rehabilitation training (47 cases) and a control group treated by medication plus rehabilitation training (45 cases), and the therapeutic effect was compared after 20 sessions.Results: The pain was relieved more obviously in the treatment group than in the control group (P<0.05),and the total effective rate was 91.8% and 71.1% respectively (P<0.01). Conclusion: Warming needle plus rehabilitation training was superior in the therapeutic effect and duration of producing relief of pain to medication plus rehabilitation training in treating chondromalacia patellae.

  20. SU-D-210-07: The Dependence On Acoustic Velocity of Medium On the Needle Template and Electronic Grid Alignment in Ultrasound QA for Prostate Brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    Kapoor, P; Kapoor, R; Curran, B [Virginia Commonwealth University, Richmond, VA (United States); HH McGuire VA Hospital, Richmond, VA (United States)

    2015-06-15

    Purpose: To analyze the impact on acoustic velocity (AV) of two different media (water and milk) using the needle template/electronic grid alignment test. Water, easily available, makes a good material to test the alignment of the template and grid although water’s AV (1498 m/s at 25°C) is significantly different from tissue (1540 m/s). Milk, with an AV much closer (1548 m/s) to prostate tissue, may be a good substitute for water in ultrasound quality assurance testing. Methods: Tests were performed using a Hitachi ultrasound unit with a mechanical arrangement designed to position needles parallel to the transducer. In this work, two materials – distilled water and homogenized whole milk (AVs of 1498 and 1548 m/s at 25°C) were used in a phantom to test ultrasound needle/grid alignment. The images were obtained with both materials and analyzed for their placement accuracy. Results: The needle template/electronic grid alignment tests showed displacement errors between measured and calculated values. The measurements showed displacements of 2.3mm (water) and 0.4mm (milk), and 1.6mm (water) and 0.3mm (milk) at depths of 7cm and 5cm respectively from true needle positions. The calculated results showed a displacement of 2.36 mm (water); 0.435mm (milk), and 1.66mm (water) and 0.31mm (milk) at a depth of 7cm and 5cm respectively. The displacements in the X and Y directions were also calculated. At depths of 7cm and 5cm, the (ΔX,ΔY) displacements in water were (0.829mm, 2.21mm) and (0.273mm, 1.634mm) and for milk were (0.15mm, 0.44mm) and (0.05mm, 0.302mm) respectively. Conclusion: The measured and calculated values were in good agreement for all tests. They show that milk provides superior results when performing needle template and electronic grid alignment tests for ultrasound units used in prostate brachytherapy.

  1. A novel CMOS transducer for giant magnetoresistance sensors

    Science.gov (United States)

    Luong, Van Su; Lu, Chih-Cheng; Yang, Jing-Wen; Jeng, Jen-Tzong

    2017-02-01

    In this work, an ASIC (application specific integrated circuits) transducer circuit for field modulated giant magnetoresistance (GMR) sensors was designed and fabricated using a 0.18-μ m CMOS process. The transducer circuits consist of a frequency divider, a digital phase shifter, an instrument amplifier, and an analog mixer. These comprise a mix of analog and digital circuit techniques. The compact chip size of 1.5 mm × 1.5 mm for both analog and digital parts was achieved using the TSMC18 1P6M (1-polysilicon 6-metal) process design kit, and the characteristics of the system were simulated using an HSpice simulator. The output of the transducer circuit is the result of the first harmonic detection, which resolves the modulated field using a phase sensitive detection (PSD) technique and is proportional to the measured magnetic field. When the dual-bridge GMR sensor is driven by the transducer circuit with a current of 10 mA at 10 kHz, the observed sensitivity of the field sensor is 10.2 mV/V/Oe and the nonlinearity error was 3% in the linear range of ±1 Oe. The performance of the system was also verified by rotating the sensor system horizontally in earth's magnetic field and recording the sinusoidal output with respect to the azimuth angle, which exhibits an error of less than ±0.04 Oe. These results prove that the ASIC transducer is suitable for driving the AC field modulated GMR sensors applied to geomagnetic measurement.

  2. Investigation of inductively coupled ultrasonic transducer system for NDE.

    Science.gov (United States)

    Zhong, Cheng Huan; Croxford, Anthony J; Wilcox, Paul D

    2013-06-01

    Inductive coupling offers a simple solution to wirelessly probe ultrasonic transducers. This paper investigates the theory and feasibility of such an inductively coupled transducer system in the context of nondestructive evaluation (NDE) applications. The noncontact interface is based on electromagnetic coupling between three coils; one of the coils is physically connected to the transducer, the other two are in a separate probing unit, where they are connected to the transmit and receive channels of the instrumentation. The complete system is modeled as a three-port network with the measured impedance of a bonded piezoelectric ceramic disc representing a sensor attached to an arbitrary solid substrate. The developed transmission line model is a function of the physical parameters of the electromagnetic system, such as the number of turns and diameter of each coil, and their separation. This model provides immediate predictions of electrical input impedance and pulse-echo response. The model has been validated experimentally and a sensitivity analysis of the input parameters performed. This has enabled optimization of the various parameters. Inductively coupled transducer systems have been built for both bulk and guided wave examples. By using chirped excitation and baseline subtraction, inspection distance of up to 700 mm is achieved in single-shot, guided-wave pulse-echo mode measurements with a 5 mm separation between the probing coils and transducer coil on an aluminum plate structure. In the bulk wave example, a delamination in an 8.9-mm-thick carbon fiber composite specimen is successfully identified from the changes in the arrival time of a reflected pulse.

  3. A model to predict deflection of bevel-tipped active needle advancing in soft tissue.

    Science.gov (United States)

    Datla, Naresh V; Konh, Bardia; Honarvar, Mohammad; Podder, Tarun K; Dicker, Adam P; Yu, Yan; Hutapea, Parsaoran

    2014-03-01

    Active needles are recently being developed to improve steerability and placement accuracy for various medical applications. These active needles can bend during insertion by actuators attached to their bodies. The bending of active needles enables them to be steered away from the critical organs on the way to target and accurately reach target locations previously unachievable with conventional rigid needles. These active needles combined with an asymmetric bevel-tip can further improve their steerability. To optimize the design and to develop accurate path planning and control algorithms, there is a need to develop a tissue-needle interaction model. This work presents an energy-based model that predicts needle deflection of active bevel-tipped needles when inserted into the tissue. This current model was based on an existing energy-based model for bevel-tipped needles, to which work of actuation was included in calculating the system energy. The developed model was validated with needle insertion experiments with a phantom material. The model predicts needle deflection reasonably for higher diameter needles (11.6% error), whereas largest error was observed for the smallest needle diameter (24.7% error).

  4. The hydraulic conductivity of the xylem in conifer needles (Picea abies and Pinus mugo).

    Science.gov (United States)

    Charra-Vaskou, Katline; Mayr, Stefan

    2011-08-01

    Main resistances of the plant water transport system are situated in leaves. In contrast to angiosperm leaves, knowledge of conifer needle hydraulics and of the partitioning of resistances within needles is poor. A new technique was developed which enabled flow-meter measurements through needles embedded in paraffin and thus quantification of the specific hydraulic conductivity (K(s)) of the needle xylem. In Picea abies, xylem K(s) of needle and axes as well as in needles of different age were compared. In Pinus mugo, resistance partitioning within needles was estimated by measurements of xylem K(s) and leaf conductance (K(leaf), measured via 'rehydration kinetics'). Mean K(s) in P. abies needles was 3.5×10(-4) m(2) s(-1) MPa(-1) with a decrease in older needles, and over all similar to K(s) of corresponding axes xylem. In needles of P. mugo, K(s) was 0.9×10(-4) m(2) s(-1) MPa(-1), and 24% of total needle resistance was situated in the xylem. The results indicate species-specific differences in the hydraulic efficiency of conifer needle xylem. The vascular section of the water transport system is a minor but relevant resistance in needles.

  5. Endophyte communities vary in the needles of Norway spruce clones.

    Science.gov (United States)

    Rajala, Tiina; Velmala, Sannakajsa M; Tuomivirta, Tero; Haapanen, Matti; Müller, Michael; Pennanen, Taina

    2013-03-01

    Endophytic fungi show no symptoms of their presence but can influence the performance and vitality of host trees. The potential use of endophytes to indicate vitality has been previously realized, but a standard protocol has yet to be developed due to an incomplete understanding of the factors that regulate endophyte communities. Using a culture-free molecular approach, we examined the extent to which host genotype influences the abundance, species richness, and community composition of endophytic fungi in Norway spruce needles. Briefly, total DNA was extracted from the surface-sterilized needles of 30 clones grown in a nursery field and the copy number of the fungal internal transcribed spacer (ITS) region of ribosomal DNA was estimated by quantitative PCR. Fungal species richness and community composition were determined by denaturing gradient gel electrophoresis and DNA sequencing. We found that community structure and ITS copy number varied among spruce clones, whereas species richness did not. Host traits interacting with endophyte communities included needle surface area and the location of cuttings in the experimental area. Although Lophodermium piceae is considered the dominant needle endophyte of Norway spruce, we detected this species in only 33% of samples. The most frequently observed fungus (66%) was the potentially pathogenic Phoma herbarum. Interestingly, ITS copy number of endophytic fungi correlated negatively with the richness of ectomycorrhizal fungi and thus potential interactions between fungal communities and their influence on the host tree are discussed. Our results suggest that in addition to environmental factors, endophyte communities of spruce needles are determined by host tree identity and needle surface area.

  6. Needle tract seeding following percutaneous biopsy of renal cell carcinoma.

    Science.gov (United States)

    Chang, Dwayne T S; Sur, Hariom; Lozinskiy, Mikhail; Wallace, David M A

    2015-09-01

    A 66-year-old man underwent computed tomography-guided needle biopsy of a suspicious renal mass. Two months later he underwent partial nephrectomy. Histology revealed a 30-mm clear cell renal cell carcinoma, up to Fuhrman grade 3. An area of the capsule was interrupted, which corresponded to a hemorrhagic area on the cortical surface. Under microscopy, this area showed a tongue of tumor tissue protruding through the renal capsule. A tumor deposit was found in the perinephric fat. These features suggest that tumor seeding may have occurred during the needle biopsy.

  7. The Gothic arch (needle point) tracing and condylar inclination.

    Science.gov (United States)

    el-Gheriani, A S; Winstanley, R B

    1987-11-01

    The records of 11 patients referred for treatment of TMJ disorders were used to compare condylar inclination found by drawing a tangent and by using a mathematic technique. Needle point tracing angles were also measured for the same patients and were compared with the condylar inclination. It can be concluded that (1) the mathematic technique outlined records a more accurate condylar angulation, and (2) there is a great variation in condylar inclination values between patients and between left and right sides of the same patient, and (3) there is no direct relationship between condylar inclination and the needle point tracing angle.

  8. Immediate effect of Fu's subcutaneous needling for low back pain

    Institute of Scientific and Technical Information of China (English)

    FU Zhong-hua; CHEN Xin-yuan; LU Li-juan; LIN Jian; XU Jian-guo

    2006-01-01

    @@ The traditional Chinese acupuncture has been reported to alleviate pain and is widely accepted as a complement therapy for pain relief in the world.1In 1996, a novel acupuncture strategy, Fu's subcutaneous needling (FSN), was developed from the traditional Chinese acupuncture, but quite different from it.2 In FSN, needles are penetrated and swayed in the subcutaneous layer, but not the muscular layer. The choosing of its insertion points doesn't obey the principles of traditional Chinese medicine. To date, FSN has been widely used by clinicians in China for its good job in pain management though the systemic and rigorous studies are still lack.

  9. EUS-Guided Needle-Based Confocal Laser Endomicroscopy

    DEFF Research Database (Denmark)

    Bhutani, Manoop S; Koduru, Pramoda; Joshi, Virendra;

    2015-01-01

    the gut, providing further diagnostic and staging information. Confocal laser endomicroscopy (CLE) is a novel endoscopic method that enables imaging at a subcellular level of resolution during endoscopy, allowing up to 1000-fold magnification of tissue and providing an optical biopsy. A new procedure...... that has been developed in the past few years is needle-based confocal laser endomicroscopy (nCLE), which involves a mini-CLE probe that can be passed through a 1 9-gauge needle during EUS-FNA. This enables the real-time visualization of tissue at a microscopic level, with the potential to further improve...

  10. Laparoscopic removal of a needle from the pancreas

    Directory of Open Access Journals (Sweden)

    Amit Jain

    2013-01-01

    Full Text Available Foreign bodies inside the pancreas are rare and usually occur after the ingestion of sharp objects like fish bone, sewing needle and toothpick. Most of the ingested foreign bodies pass spontaneously through the anus without being noticed but about 1% of them can perforate through the wall of stomach or duodenum to reach solid organs like pancreas or liver. Once inside the pancreas they can produce complications like abscess, pseudoaneurysm or pancreatits. Foreign bodies of pancreas should be removed by endoscopic or surgical methods. We hereby report our experience of successful removal one a sewing needle from pancreas.

  11. The measurement of tremor using a velocity transducer: comparison to simultaneous recordings using transducers of displacement, acceleration and muscle activity.

    Science.gov (United States)

    Norman, K E; Edwards, R; Beuter, A

    1999-10-15

    Precise kinematic measurements of tremor have historically been obtained using accelerometers. However, current technology permits precise measurements in velocity and displacement. The primary advantage of velocity recording is that only one step of integration or differentiation is required for either displacement or acceleration. A method is presented of measuring finger tremor using a laser system that transduces velocity precisely. Measurements of postural finger tremor thus obtained were compared to those simultaneously obtained from a laser system that transduces displacement, from an accelerometer and from surface electromyography (EMG) of the extensor digitorum communis. A range of amplitude and frequency content was obtained by testing control subjects and subjects with Parkinson's disease. The velocity transducer showed excellent correspondence of amplitude and frequency measurement with the displacement transducer. Measures of absolute and relative amplitude correlated well (r > or = 0.96 in amplitude measures in displacement, velocity and acceleration), and high coherence was found throughout the frequency range of interest. Measurements by the accelerometer generally showed poorer correspondence with those of the other instruments. EMG measurements showed good correspondence in some trials but poorer correspondence in others, attributed to the low level of muscle activity required in the task. Precise kinematic measurements appear to be highly sensitive to neuromotor impairment.

  12. PMN-PT single crystal focusing transducer fabricated using a mechanical dimpling technique.

    Science.gov (United States)

    Lam, K H; Chen, Y; Cheung, K F; Dai, J Y

    2012-01-01

    A ∼5MHz focusing PMN-PT single crystal ultrasound transducer has been fabricated utilizing a mechanical dimpling technique, where the dimpled crystal wafer was used as an active element of the focusing transducer. For the dimpled focusing transducer, the effective electromechanical coupling coefficient was enhanced significantly from 0.42 to 0.56. The dimpled transducer also yields a -6dB bandwidth of 63.5% which is almost double the bandwidth of the plane transducer. An insertion loss of the dimpled transducer (-18.1dB) is much lower than that of the plane transducer. Finite element simulation also reveals specific focused beam from concave crystal surface. These promising results show that the dimpling technique can be used to develop high-resolution focusing single crystal transducers.

  13. Six-Axis Force-Torque Transducer for Mars 2018 Mission Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A transducer element that is hearty enough for a Mars lander mission needs to be developed so that a six-axis force and torque transducer is possible. The technical...

  14. Wideband Single-Crystal Transducer for Bone Characterization

    Science.gov (United States)

    Liang, Yu; Snook, Kevin

    2012-01-01

    The microgravity conditions of space travel result in unique physiological demands on the human body. In particular, the absence of the continual mechanical stresses on the skeletal system that are present on Earth cause the bones to decalcify. Trabecular structure decreases in thickness and increases in spacing, resulting in decreased bone strength and increased risk of injury. Thus, monitoring bone health is a high priority for long-term space travel. A single probe covering all frequency bands of interest would be ideal for such measurements, and this would also minimize storage space and eliminate the complexity of integrating multiple probes. This invention is an ultrasound transducer for the structural characterization of bone. Such characterization measures features of reflected and transmitted ultrasound signals, and correlates these signals with bone structure metrics such as bone mineral density, trabecular spacing, and thickness, etc. The techniques used to determine these various metrics require measurements over a broad range of ultrasound frequencies, and therefore, complete characterization requires the use of several narrowband transducers. This is a single transducer capable of making these measurements in all the required frequency bands. The device achieves this capability through a unique combination of a broadband piezoelectric material; a design incorporating multiple resonator sizes with distinct, overlapping frequency spectra; and a micromachining process for producing the multiple-resonator pattern with common electrode surfaces between the resonators. This device consists of a pattern of resonator bars with common electrodes that is wrapped around a central mandrel such that the radiating faces of the resonators are coplanar and can be simultaneously applied to the sample to be measured. The device operates as both a source and receiver of acoustic energy. It is operated by connection to an electronic system capable of both providing an

  15. Dissimilar trend of nonlinearity in ultrasound transducers and systems at resonance and non-resonance frequencies

    DEFF Research Database (Denmark)

    Ghasemi, Negareh; Zare, Firuz; Davari, Pooya;

    2017-01-01

    Several factors can affect performance of an ultrasound system such as quality of excitation signal and ultrasound transducer behaviour. Nonlinearity of piezoelectric ultrasound transducers is a key determinant in designing a proper driving power supply. Although, the nonlinearity of piezoelectric...... transducer impedance has been discussed in different literatures, the trend of the nonlinearity at different frequencies with respect to excitation voltage variations has not been clearly investigated in practice. In this paper, to demonstrate how the nonlinearity behaves, a sandwich piezoceramic transducer...

  16. Eddy Current Transducer Dedicated for Sigma Phase Evaluation in Duplex Stainless Steel

    Directory of Open Access Journals (Sweden)

    Grzegorz Psuj

    2012-01-01

    Full Text Available The paper describes a new transducer dedicated for evaluation of a duplex stainless steel (DSS. Different phases which exist in DSS have influence on mechanical as well as on electrical properties. Therefore, an eddy current transducer was utilized. In order to achieve high sensitivity, a differential type of the transducer was selected. The performance of the transducer was verified by utilizing the samples which had a different amount of sigma phase.

  17. Modeling the radiation of ultrasonic phased-array transducers with Gaussian beams.

    Science.gov (United States)

    Huang, Ruiju; Schmerr, Lester W; Sedov, Alexander

    2008-12-01

    A new transducer beam model, called a multi-Gaussian array beam model, is developed to simulate the wave fields radiated by ultrasonic phased-array transducers. This new model overcomes the restrictions on using ordinary multi-Gaussian beam models developed for large single-element transducers in phased-array applications. It is demonstrated that this new beam model can effectively model the steered and focused beams of a linear phased-array transducer.

  18. One-dimensional analysis of piezoelectric transducers based on Thevenin theorem

    OpenAIRE

    Arnold, FJ

    2009-01-01

    In this work, a method of analysis of piezoelectric transducers is shown. This method is based on the simplification of Mason's equivalent electric circuit. An adaptation of Thevenin theorem has been employed to study the behavior of piezoelectric transducers used as transmitters (electric into mechanic energy conversion). This study was restricted to transducers with a typical configuration employed in high power applications. The transducers were one-dimensionally modeled, considering only ...

  19. Consideration of different heating lengths of needles with induction heating and resistance system: A novel design of needle module for thermal ablation.

    Science.gov (United States)

    Bui, Huy-Tien; Hwang, Sheng-Jye; Lee, Huei-Huang; Huang, Durn-Yuan

    2017-04-01

    Thermal ablation using alternating electromagnetic fields is a promising method to treat tissues including tumors. With this approach, an electromagnetic field is generated around an induction coil, which is supplied with high frequency current from a power source. Any electrically conducting object, which is placed in the electromagnetic field, is then heated due to eddy currents. Basic principles underlying this novel thermotherapy needle system are internal induction and resistance heating. This presents a new design of a standard gauge 18 percutaneous trans-hepatic cholangiography needle module combined with a compact power source. Three needle modules containing coils of different lengths were used to locally heat up different volumes of tissues in in vitro experiments on pig livers. Temperature on the inside surface of the needle was controlled and monitored through a K-type thermocouple. By using this needle module system, no two-section or ferromagnetic nanoparticle-coated needles were required; the system worked well with the SUS-304 stainless-steel needle. Successful results were demonstrated in the in vitro experiments on pig livers with different heating lengths of 10, 20, and 30 mm needles. With low power sources, needles could be heated up to a high temperature. The novel design of the needle module incorporated with a high frequency power source was thus shown to be a promising technology for tissue ablation. Bioelectromagnetics.38:220-226, 2017. © 2016 Wiley Periodicals, Inc.

  20. Forced and free displacement characterization of ionic polymer transducers

    Science.gov (United States)

    Akle, Barbar J.; Duncan, Andrew; Akle, Etienne; Wallmersperger, Thomas; Leo, Donald J.

    2009-03-01

    Ionic polymer transducers (IPT), sometimes referred to as artificial muscles, are known to generate a large bending strain and a moderate stress at low applied voltages (transducers. In this study, extensional IPTs are characterized under forced and free displacement boundary condition as a function of transducer architecture. The electrode thickness is varied from 10 μm up to 40 μm while three extensional actuators with Lithium, Cesium, and tetraethylammonium (TEA) mobile cations are characterized. Three fixtures are built in order to characterize the extensional actuation response. The first fixture measures the free displacement of an IPT sample sandwiched between two aluminum plates glued using the electrically conductive silver paste. In the second fixture a spring is compressed against the test sample with variable amounts to generate different levels of pre-stress and prevents the bending of the IPT. In the third fixture dead weights are placed on top of the sample in order to prevent bending. In the spring loaded fixture a thermocouple is placed in the proximity of the actuator and temperature is measured. The different transducers are characterized using a step voltage input and an alternating current (AC) sine wave input. The step input resulted in a logarithmic rise like displacement curve, while the low frequency (wave displacement response with a strong first harmonic. The high frequency AC excitation generated a response similar to that of the step input. Comparing the measured temperature for step and AC response demonstrated that the sample is heating up when exited with a high frequency signal; which is leading to the expansion of the sample. Initial experimental results demonstrate a strong correlation between electrode architecture and the peak strain response. Strains on the order of 2% are observed with air stable ionic liquid based transducers. A correlation between the strain and charge buildup in the polymer is also characterized. Cesium

  1. Progress towards developing neutron tolerant magnetostrictive and piezoelectric transducers

    Energy Technology Data Exchange (ETDEWEB)

    Reinhardt, Brian; Tittmann, Bernhard [The Pennsylvania State University (United States); Rempe, Joy; Daw, Joshua [Idaho National Laboratory (United States); Kohse, Gordon; Carpenter, David; Ames, Michael; Ostrovsky, Yakov [Massachusetts Institute of Technology (United States); Ramuhalli, Pradeep; Montgomery, Robert [Pacific Northwest National Laboratory (United States); Chien, Hualte [Argonne National Laboratory (United States); Wernsman, Bernard [Bechtel Marine Propulsion Corp (United States)

    2015-03-31

    Current generation light water reactors (LWRs), sodium cooled fast reactors (SFRs), small modular reactors (SMRs), and next generation nuclear plants (NGNPs) produce harsh environments in and near the reactor core that can severely tax material performance and limit component operational life. To address this issue, several Department of Energy Office of Nuclear Energy (DOE-NE) research programs are evaluating the long duration irradiation performance of fuel and structural materials used in existing and new reactors. In order to maximize the amount of information obtained from Material Testing Reactor (MTR) irradiations, DOE is also funding development of enhanced instrumentation that will be able to obtain in-situ, real-time data on key material characteristics and properties, with unprecedented accuracy and resolution. Such data are required to validate new multi-scale, multi-physics modeling tools under development as part of a science-based, engineering driven approach to reactor development. It is not feasible to obtain high resolution/microscale data with the current state of instrumentation technology. However, ultrasound-based sensors offer the ability to obtain such data if it is demonstrated that these sensors and their associated transducers are resistant to high neutron flux, high gamma radiation, and high temperature. To address this need, the Advanced Test Reactor National Scientific User Facility (ATR-NSUF) is funding an irradiation, led by PSU, at the Massachusetts Institute of Technology Research Reactor to test the survivability of ultrasound transducers. As part of this effort, PSU and collaborators have designed, fabricated, and provided piezoelectric and magnetostrictive transducers that are optimized to perform in harsh, high flux, environments. Four piezoelectric transducers were fabricated with either aluminum nitride, zinc oxide, or bismuth titanate as the active element that were coupled to either Kovar or aluminum waveguides and two

  2. Progress towards developing neutron tolerant magnetostrictive and piezoelectric transducers

    Science.gov (United States)

    Reinhardt, Brian; Tittmann, Bernhard; Rempe, Joy; Daw, Joshua; Kohse, Gordon; Carpenter, David; Ames, Michael; Ostrovsky, Yakov; Ramuhalli, Pradeep; Montgomery, Robert; Chien, Hualte; Wernsman, Bernard

    2015-03-01

    Current generation light water reactors (LWRs), sodium cooled fast reactors (SFRs), small modular reactors (SMRs), and next generation nuclear plants (NGNPs) produce harsh environments in and near the reactor core that can severely tax material performance and limit component operational life. To address this issue, several Department of Energy Office of Nuclear Energy (DOE-NE) research programs are evaluating the long duration irradiation performance of fuel and structural materials used in existing and new reactors. In order to maximize the amount of information obtained from Material Testing Reactor (MTR) irradiations, DOE is also funding development of enhanced instrumentation that will be able to obtain in-situ, real-time data on key material characteristics and properties, with unprecedented accuracy and resolution. Such data are required to validate new multi-scale, multi-physics modeling tools under development as part of a science-based, engineering driven approach to reactor development. It is not feasible to obtain high resolution/microscale data with the current state of instrumentation technology. However, ultrasound-based sensors offer the ability to obtain such data if it is demonstrated that these sensors and their associated transducers are resistant to high neutron flux, high gamma radiation, and high temperature. To address this need, the Advanced Test Reactor National Scientific User Facility (ATR-NSUF) is funding an irradiation, led by PSU, at the Massachusetts Institute of Technology Research Reactor to test the survivability of ultrasound transducers. As part of this effort, PSU and collaborators have designed, fabricated, and provided piezoelectric and magnetostrictive transducers that are optimized to perform in harsh, high flux, environments. Four piezoelectric transducers were fabricated with either aluminum nitride, zinc oxide, or bismuth titanate as the active element that were coupled to either Kovar or aluminum waveguides and two

  3. CLINICAL OBSERVATION ON TREATMENT OF 120CASES OF PERIPHERY FACIAL PARALYSIS WITH PENETRATION NEEDLING

    Institute of Scientific and Technical Information of China (English)

    王芳妮

    2000-01-01

    In the present study,the therapeutic effect of penetration needling was observed in 120cases facial paralysis patients and compared with that of the routine needling in another105cases.Re-sults showed that though no significant difference was found between these two groups in the therapeu-tic effect,the acupoints used were fewer in penetration needling group and its effect on tear and poste-rior-auricular pain was superior to that of routine needling.

  4. Transducer models in the ultrasound simulation program FIELD II and their accuracy

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt; Bæk, David

    2010-01-01

    companies for investigation novel transducer geometries and advanced linear imaging schemes. The program models transducer geometries using a division of the transducer elements into either rectangles, triangles, or bounding lines. The precision of the simulation and the simulation time is intimately linked...

  5. Effects of insertion speed and trocar stiffness on the accuracy of needle position for brachytherapy

    Energy Technology Data Exchange (ETDEWEB)

    McGill, Carl S.; Schwartz, Jonathon A.; Moore, Jason Z.; McLaughlin, Patrick W.; Shih, Albert J. [Biomedical Engineering Department, University of Michigan, Ann Arbor, Michigan 48109 (United States); Department of Mechanical and Nuclear Engineering, The Pennsylvania State University, State College, Pennsylvania 16802 (United States); Department of Radiation Oncology, University of Michigan, Ann Arbor, Michigan 48109 (United States); Biomedical Engineering Department, University of Michigan, Ann Arbor, Michigan 48109 and Mechanical Engineering Department, University of Michigan, Ann Arbor, Michigan 48109 (United States)

    2012-04-15

    Purpose: In prostate brachytherapy, accurate positioning of the needle tip to place radioactive seeds at its target site is critical for successful radiation treatment. During the procedure, needle deflection leads to seed misplacement and suboptimal radiation dose to cancerous cells. In practice, radiation oncologists commonly use high-speed hand needle insertion to minimize displacement of the prostate as well as the needle deflection. Effects of speed during needle insertion and stiffness of trocar (a solid rod inside the hollow cannula) on needle deflection are studied. Methods: Needle insertion experiments into phantom were performed using a 2{sup 2} factorial design (2 parameters at 2 levels), with each condition having replicates. Analysis of the deflection data included calculating the average, standard deviation, and analysis of variance (ANOVA) to find significant single and two-way interaction factors. Results: The stiffer tungsten carbide trocar is effective in reducing the average and standard deviation of needle deflection. The fast insertion speed together with the stiffer trocar generated the smallest average and standard deviation for needle deflection for almost all cases. Conclusions: The combination of stiff tungsten carbide trocar and fast needle insertion speed are important to decreasing needle deflection. The knowledge gained from this study can be used to improve the accuracy of needle insertion during brachytherapy procedures.

  6. Computational design optimization of an SMA-based active steerable needle

    Science.gov (United States)

    Konh, Bardia; Hutapea, Parsaoran

    2015-04-01

    Shape memory alloy (SMA) actuated needle is currently being developed to assist surgeons/physicians in their percutaneous interventional procedures. The proposed active surgical needle can potentially compensate the possible misplacements of the needle tip in the tissue benefiting from the improved navigation provided by the attached SMA actuators. In this study finite element tools have been utilized in order to maintain an optimum design of the active needle configuration. There are several parameters involved in the design affecting the active needle's applicability and maneuverability; among them are the length, diameter and the maximum residual strain of the SMA wires, the stiffness and diameters of the surgical needle and the offset distance between the needle and the actuator. For analyzing the response of the active needle structure a parametric model was developed in ANSYS. This model was linked to the automated optimization tools for an improved design of the active needle. The most sensitive parameters affecting the active needle's steerability were found to be the offset distance and the length of the needle. Considering the results and the clinical limitations, an improved design of the active needle was presented.

  7. Mechanics-Based Model for Predicting In-Plane Needle Deflection with Multiple Bends

    NARCIS (Netherlands)

    Roesthuis, R.J.; Abayazid, M.; Misra, S.

    2012-01-01

    Bevel-tipped flexible needles naturally bend when inserted into soft tissue. Steering such needles along curved paths allows one to avoid anatomical obstacles and reach locations inside the human body which are unreachable with rigid needles. In this study, a mechanics-based model is presented which

  8. COMMENTS ON CLINICAL APPLICATION OF LOCAL MULTI-NEEDLE PUNCTURING

    Institute of Scientific and Technical Information of China (English)

    MENG Xiangwen

    2002-01-01

    In the present paper, combining a few of typical cases, the author introduces his clinical experiences about the application of multiple acupuncture needles inserted into a certain local region for treatment of facial spasm,Iumbago, hyperplasis of the mammay glands and herpes zoster and gives some brief comments.

  9. Structural peculiarities of single crystal diamond needles of nanometer thickness

    Science.gov (United States)

    Orekhov, Andrey S.; Tuyakova, Feruza T.; Obraztsova, Ekaterina A.; Loginov, Artem B.; Chuvilin, Andrey L.; Obraztsov, Alexander N.

    2016-11-01

    Diamond is attractive for various applications due to its unique mechanical and optical properties. In particular, single crystal diamond needles with high aspect ratios and sharp apexes of nanometer size are demanded for different types of optical sensors including optically sensing tip probes for scanning microscopy. This paper reports on electron microscopy and Raman spectroscopy characterization of the diamond needles having geometrically perfect pyramidal shapes with rectangular atomically flat bases with (001) crystallography orientation, 2-200 nm sharp apexes, and with lengths from about 10-160 μm. The needles were produced by selective oxidation of (001) textured polycrystalline diamond films grown by chemical vapor deposition. Here we study the types and distribution of defects inside and on the surface of the single crystal diamond needles. We show that sp3 type point defects are incorporated into the volume of the diamond crystal during growth, while the surface of the lateral facets is enriched by multiple extended defects. Nitrogen addition to the reaction mixture results in increase of the growth rate on {001} facets correlated with the rise in the concentration of sp3 type defects.

  10. Macroscopic and microscopic observations of needle insertion into gels

    NARCIS (Netherlands)

    Veen, van Youri R.J.; Jahya, Alex; Misra, Sarthak

    2012-01-01

    Needle insertion into soft tissue is one of the most common medical interventions. This study provides macroscopic and microscopic observations of needle–gel interactions. A gelatin mixture is used as a soft-tissue simulant. For the macroscopic studies, system parameters, such as insertion velocity,

  11. Thin-needle aspiration biopsy of the prostate.

    Science.gov (United States)

    Koss, L G; Woyke, S; Schreiber, K; Kohlberg, W; Freed, S Z

    1984-05-01

    The authors summarize the current status of thin-needle aspiration biopsy of the prostate and evaluate the accomplishments and limitations of this method of diagnosis. Historical developments, indications, technique, contraindications, complications, cytology of aspirates, diagnostic efficacy of aspirates, and grading of prostatic carcinomas are discussed.

  12. Main flavonoids in needles of Larix decidu A

    NARCIS (Netherlands)

    Niemann, Gerard J.

    1975-01-01

    Present work. Freeze-dried needles were extracted with acetone-water. Ether and butanol fractions were separated by repeated banding on paper. Nine major flavonoids were isolated (in solution) and identified by chromatographic and UV spectral data of both the original and alkaline and/or acid hydrol

  13. Failed needle decompression of bilateral spontaneous tension pneumothorax.

    Science.gov (United States)

    Bach, P T; Sølling, C

    2015-07-01

    This case report presents a young male admitted with primary bilateral spontaneous tension pneumothorax and severe respiratory distress. This is an extremely rare condition. The patient was on the verge of hypoxic cardiac arrest and the attempted needle thoracocentesis was unsuccessful. Needle thoracocentesis in the midclavicular line of the second intercostal space is widely used and recommended as first-line treatment of tension pneumothorax. Reviewing the literature, the procedure is not based on solid evidence. It has high failure rates and potentially serious complications. Alternatives to this approach are perhaps more appropriate. Correctly done, needle thoracocentesis has its place in the presence of a diagnosed or suspected tension pneumothorax when no other options are available. If needle thoracocentesis is chosen, then insertion in the mid-anterior axillary line of the 3rd-5th intercostal space is an appropriate alternative site. Otherwise, lateral thoracostomy, with or without chest tube insertion, is a safe procedure with a high success rate. It should be considered as the first-line treatment of tension pneumothorax, particularly in the unstable patient.

  14. Superficial Needling Therapy for Tennis Elbow in 40 Cases

    Institute of Scientific and Technical Information of China (English)

    GE Heng-bi; XIAO Yuan-chun

    2003-01-01

    Superficial needling therapy was employed to treat 40 cases of tennis elbow. For the cases of qi and blood stagnation, cupping therapy was added. Thirty-eight cases were cured after one treatment and 2 cases were cured after two treatments.

  15. Emerging Needle Blight Diseases in Atlantic Pinus Ecosystems of Spain

    Directory of Open Access Journals (Sweden)

    Esther Ortíz de Urbina

    2016-12-01

    Full Text Available Red band needle blight caused by Dothistroma septosporum and D. pini, and brown spot needle blight caused by Lecanosticta acicola provoke severe and premature defoliation in Pinus, and subsequent reduction of photosynthetic surfaces, vitality, and growth in young and adult trees. The recurrent damage results in branch and tree death. Until recently, pine needle blight diseases have had only minor impacts on native and exotic forest trees in the North of Spain, but in the past five years, these pathogen species have spread widely and caused severe defoliation and mortality in exotic and native plantations of Pinus in locations where they were not detected before. In an attempt to understand the main causes of this outbreak and to define the effectiveness of owners’ management strategies, four research actions were implemented: a survey of the management activities implemented by the owners to reduce disease impact, the evaluation of specific symptoms and damage associated with infection, and the identification of the causative pathogenic species and their reproductive capacity. Morphological characteristics of the fungus and molecular identification were consistent with those of Lecanosticta acicola and Dothistroma spp., D. septosporum, D. Pini, and both mating types were present for the three identified pathogens. The local silvicultural management performed, mainly pruning and thinning, was not resulting in the expected improvement. The results of this study can be applied to establish guidelines for monitoring and controlling the spread of needle blight pathogens.

  16. Measuring static and dynamic contact angles using a liquid needle

    Science.gov (United States)

    Sanedrin, Raymond; Jin, Ming; Frese, Daniel; Scheithauer, Carsten; Willers, Thomas

    2016-11-01

    The optical determination of static and advancing contact angle is made on drops applied or extended, respectively, onto a substrate through the use of thin solid needles. Although this method has been used extensively, this method of dosing can be time consuming, cumbersome and if not meticulously performed can lead to erroneous contact angle results. Herein, we present an alternative way of applying drops onto substrates using a small liquid jet, which is produced by a liquid pressure dosing system acting as a "liquid needle." A comparative static contact angle study on 14 different surfaces with two different liquids were performed utilizing two different ways of dosing: the conventional solid and a novel liquid needle based technique. We found, for all but one sample, that the obtained results were highly comparable. Observed differences can be explained by the characteristics of either way of dosing. In addition, we used the liquid pressure based dosing system for optical advancing contact angle measurement on two different samples. The liquid needle based method facilitates the expansion of a drop from 0.1 to 22 μL within less than 1.2 seconds, which provided constant contact angle versus drop base diameter curves. The obtained results were highly comparable with dynamic Wilhelmy contact angle measurements.

  17. Core needle biopsy guidance based on EMOCT imaging (Conference Presentation)

    Science.gov (United States)

    Iftimia, Nicusor V.; Park, Jesung; Maguluri, Gopi

    2016-03-01

    We present a novel method, based on encoder mapping OCT imaging, for real-time guidance of core biopsy procedures. This method provides real-time feedback to the interventional radiologist, such that he/she can reorient the needle during the biopsy and sample the most representative area of the suspicious mass that is being investigated. This aspect is very important for tailoring therapy to the specific cancer based on biomarker analysis, which will become one of the next big advances in our search for the optimal cancer therapy. To enable individualized treatment, the genetic constitution and the DNA repair status in the affected areas is needed for each patient. Thus, representative sampling of the tumor is needed for analyzing various biomarkers, which are used as a tool to personalize cancer therapy. The encoder-based OCT enables samping of large size masses and provides full control on the imaging probe, which is passed through the bore of the biopsy guidance needle. The OCT image is built gradually, based on the feedback of an optical encoder which senses the incremental movement of the needle with a few microns resolution. Tissue mapping is independent of the needle speed, while it is advanced through the tissue. The OCT frame is analyzed in real-time and tissue cellularity is reported in a very simple manner (pie chart). Our preliminary study on a rabbit model of cancer has demonstrated the capability of this technology for accurately differentiating between viable cancer and heterogeneous or necrotic tissue.

  18. Needle electromyographic findings in 98 patients with myositis.

    NARCIS (Netherlands)

    Blijham, P.J.; Hengstman, G.J.D.; Hama-Amin, A.D.; Engelen, B.G.M. van; Zwarts, M.J.

    2006-01-01

    BACKGROUND/AIMS: Little is known about the distribution of electromyographic (EMG) abnormalities in myositis even though this is relevant in daily practice. METHODS: A retrospective semiquantitative analysis of needle EMG findings was performed in a group of 98 patients with myositis. The frequency,

  19. Sensorimotor Learning of Acupuncture Needle Manipulation Using Visual Feedback.

    Directory of Open Access Journals (Sweden)

    Won-Mo Jung

    Full Text Available Humans can acquire a wide variety of motor skills using sensory feedback pertaining to discrepancies between intended and actual movements. Acupuncture needle manipulation involves sophisticated hand movements and represents a fundamental skill for acupuncturists. We investigated whether untrained students could improve their motor performance during acupuncture needle manipulation using visual feedback (VF.Twenty-one untrained medical students were included, randomly divided into concurrent (n = 10 and post-trial (n = 11 VF groups. Both groups were trained in simple lift/thrusting techniques during session 1, and in complicated lift/thrusting techniques in session 2 (eight training trials per session. We compared the motion patterns and error magnitudes of pre- and post-training tests.During motion pattern analysis, both the concurrent and post-trial VF groups exhibited greater improvements in motion patterns during the complicated lifting/thrusting session. In the magnitude error analysis, both groups also exhibited reduced error magnitudes during the simple lifting/thrusting session. For the training period, the concurrent VF group exhibited reduced error magnitudes across all training trials, whereas the post-trial VF group was characterized by greater error magnitudes during initial trials, which gradually reduced during later trials.Our findings suggest that novices can improve the sophisticated hand movements required for acupuncture needle manipulation using sensorimotor learning with VF. Use of two types of VF can be beneficial for untrained students in terms of learning how to manipulate acupuncture needles, using either automatic or cognitive processes.

  20. 21 CFR 884.6100 - Assisted reproduction needles.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Assisted reproduction needles. 884.6100 Section 884.6100 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES OBSTETRICAL AND GYNECOLOGICAL DEVICES Assisted Reproduction Devices §...

  1. Robotic systems for percutaneous needle-guided interventions.

    Science.gov (United States)

    Kettenbach, Joachim; Kronreif, Gernot

    2015-02-01

    Several groups have developed robotic systems for invasive medical procedures. In this article we will focus on selected robotic systems for percutaneous needle-guided interventions using CT or MR imaging. We present six interventional robotic systems designed to work with imaging modalities such as CT, Cone-beam CT and MRI. The details of each system are given along with any phantom, animal, or human trials performed with each particular robot. Although each of these systems has specific features, they are all of great clinical value since they provide very stable needle guidance -- even for angulated approaches, they may allow access to lesions when the width of the CT- or MR- gantry would limit the access for a biopsy needle or other interventional tools such as thermal ablation probes. Then, such a robot may be able to guide the needle into the most promising region of the lesion without the need for a second contrast injection. Thus, more efficacious characterization and treatment, particularly for lesions that are difficult to target, can be anticipated. Although more research and clinical trials are certainly needed, it is, however, our belief that robotic systems will be an important part of future interventions.

  2. New technique for needle-less implantation of eukaryotic cells

    NARCIS (Netherlands)

    Silva, L.F. Arenas da; Schober, L.; Sloff, M.; Traube, A.; Hart, M.L.; Feitz, W.F.J.; Stenzl, A.

    2015-01-01

    BACKGROUND AIMS: On review of the use of stem cells in the literature, promissory outcomes for functional organ recovery in many subspecialties in medicine underscore its therapeutic potential. The application of stem cells through the use of a needle can result in additional scar formation, which i

  3. Effects of percutaneous needle liver biopsy on dairy cow behaviour

    DEFF Research Database (Denmark)

    Mølgaard, Lene; Damgaard, Birthe Marie; Bjerre-Harpøth, Vibeke;

    2012-01-01

    behavioural changes for up to 19 h – and particularly for behaviour previously associated with pain. Even though the exact welfare impact of percutaneous needle liver biopsies in cows is not known, and the magnitude of the behavioural changes was limited, pain always has negative effects on animal welfare...

  4. FOULING DETECTION IN FOOD VESSELS USING INTERDIGITAL LAMB WAVE TRANSDUCER

    Institute of Scientific and Technical Information of China (English)

    JIAO Jingpin; GE Haiyan; WU Bin; HE Cunfu

    2007-01-01

    Lamb waves are used to detect fouling in food vessels. The propagation of the Lamb waves in plates exhibits many modes and dispersion characteristics, which have great influence on fouling detection. The relative distribution of the in-plane and out-of-plane displacement of the mode across the thickness of the plate will determine the sensitivity of the mode to a particular loading condition. By considering the dispersion and multi-mode characteristics of guided waves, an interdigital polyvinylidene fluoride (PVDF) transducer is designed to realize the mode selection of guided waves, and a single α0 mode is used for guided wave detection. Fouling detection experiments are conducted in the laboratory using epoxy adhesive on a thin plate. Using the interdigital PVDF transducer, three fouled areas are detected. Using one of the time-frequency analysis methods, the waveforms are further processed. This also demonstrates the validity of this method of fouling detection.

  5. The copying power of one-state tree transducers

    DEFF Research Database (Denmark)

    Engelfriet, Joost; Skyum, Sven

    1982-01-01

    One-state deterministic top-down tree transducers (or, tree homomorphisms) cannot handle “prime copying,” i.e., their class of output (string) languages is not closed under the operation L → {$(w$)f(n) short parallel w ε L, f(n) greater-or-equal, slanted 1}, where f is any integer function whose...... range contains numbers with arbitrarily large prime factors (such as a polynomial). The exact amount of nonclosure under these copying operations is established for several classes of input (tree) languages. These results are relevant to the extended definable (or, restricted parallel level) languages......, to the syntax-directed translation of context-free languages, and to the tree transducer hierarchy....

  6. Modeling of nonlinear responses for reciprocal transducers involving polarization switching

    DEFF Research Database (Denmark)

    Willatzen, Morten; Wang, Linxiang

    2007-01-01

    intrinsically. The time-dependent Ginzburg-Landau theory is used in the parameter identification involving hysteresis effects. We use the Chebyshev collocation method in the numerical simulations. The elastic field is assumed to be coupled linearly with other fields, and the nonlinearity is in the E-D coupling....... We present numerical results for the reciprocal-transducer system and identify the influence of nonlinearities on the system dynamics at high and low frequency as well as electrical impedance effects due to tuning by a series inductance. It is found that nonlinear effects are not important at high......Nonlinearities and hysteresis effects in a reciprocal PZT transducer are examined by use of a dynamical mathematical model on the basis of phase-transition theory. In particular, we consider the perovskite piezoelectric ceramic in which the polarization process in the material can be modeled...

  7. An Energy-Based Hysteresis Model for Magnetostrictive Transducers

    Science.gov (United States)

    Calkins, F. T.; Smith, R. C.; Flatau, A. B.

    1997-01-01

    This paper addresses the modeling of hysteresis in magnetostrictive transducers. This is considered in the context of control applications which require an accurate characterization of the relation between input currents and strains output by the transducer. This relation typically exhibits significant nonlinearities and hysteresis due to inherent properties of magnetostrictive materials. The characterization considered here is based upon the Jiles-Atherton mean field model for ferromagnetic hysteresis in combination with a quadratic moment rotation model for magnetostriction. As demonstrated through comparison with experimental data, the magnetization model very adequately quantifies both major and minor loops under various operating conditions. The combined model can then be used to accurately characterize output strains at moderate drive levels. The advantages to this model lie in the small number (six) of required parameters and the flexibility it exhibits in a variety of operating conditions.

  8. A novel design of micromachined capacitive Lamb wave transducers

    Science.gov (United States)

    Ge, Lifeng

    2006-11-01

    A new design for micromachined capacitive Lamb wave transducers (mCLWT) has been developed. The design is based on a theoretical TDK model previously developed for groove ultrasonic transducers. By the investigation of the dynamic behavior of a rectangular high aspect ratio diaphragm of the mCLWTs, the second order bending mode of the diaphragm is exploited to excite and detect Lamb wave. The new exiting mechanism can minimize the energy of the acoustic radiation at the normal direction of the diaphragm so as to provide more energy coupled into the Lamb wave in the silicon substrate. Also, the natural frequencies and mode shapes of such a mCLWT can be determined accurately from its geometry and materials used, so the TDK model provides guidance for the optimal design of mCLWTs.

  9. CMOS biosensors for in vitro diagnosis - transducing mechanisms and applications.

    Science.gov (United States)

    Lei, Ka-Meng; Mak, Pui-In; Law, Man-Kay; Martins, Rui P

    2016-09-21

    Complementary metal oxide semiconductor (CMOS) technology enables low-cost and large-scale integration of transistors and physical sensing materials on tiny chips (e.g., key functions of biosensors: transducing and signal processing. Recent CMOS biosensors unified different transducing mechanisms (impedance, fluorescence, and nuclear spin) and readout electronics have demonstrated competitive sensitivity for in vitro diagnosis, such as detection of DNA (down to 10 aM), protein (down to 10 fM), or bacteria/cells (single cell). Herein, we detail the recent advances in CMOS biosensors, centering on their key principles, requisites, and applications. Together, these may contribute to the advancement of our healthcare system, which should be decentralized by broadly utilizing point-of-care diagnostic tools.

  10. Broadband electrostatic acoustic transducer for ultrasonic measurements in liquids.

    Science.gov (United States)

    Cantrell, J H; Heyman, J S; Yost, W T; Torbett, M A; Breazeale, M A

    1979-01-01

    A broadband capacitive electrostatic acoustic transducer (ESAT) has been developed for use in a liquid environment at megahertz frequencies. The ESAT basically consists of a thin conductive membrane stretched over a metallic housing. The membrane functions as the ground plate of a parallel plate capacitor, the other plate being a dc biased electrode recessed approximately 10 mum from the electrically grounded membrane. An ultrasonic wave incident on the membrane varies the membrane-electrode gap spacing and generates an electrical signal proportional to the wave amplitude. The entire assembly is sealed for immersion in a liquid environment. Calibration of the ESAT with incident ultrasonic waves of constant displacement amplitude from 1 to 15 MHz reveals a decrease in signal response with increasing frequency independent of membrane tension. The use of the ESAT as a broadband ultrasonic transducer in liquids with a predictable frequency response is promising.

  11. Force transducers based on the stress dependence of coercive force

    Science.gov (United States)

    Garshelis, I. J.

    1993-05-01

    An alternative measurement regime for magnetoelastic force transducers, based on variations in coercive field, is described. Hc is shown to be more directly related to the primary magnetic influence of stress, namely, the orientation of effective anisotropy, than conventionally used magnetization related parameters. The stress dependence of Hc is shown to generally reflect opposing factors associated with rotational and wall displacement magnetization reversal processes. In materials wherein Hc≪K/Ms wall motion dominates and if the product of λs/K and yield stress is high enough, large monotonic reductions of Hc with positive (tensile) stress are shown to be possible. A more complex variation of Hc with increasing compression is similarly expected. Experimental results from a transducer having an 18% Ni maraging steel core support these expectations.

  12. An evaluation of conflation accuracy using finite-state transducers

    OpenAIRE

    Galvez, Carmen; De-Moya-Anegón, Félix

    2006-01-01

    Purpose – To evaluate the accuracy of conflation methods based on Finite-State Transducers (FSTs). Design/methodology/approach – Incorrectly lemmatized and stemmed forms may lead to the retrieval of inappropriate documents. Experimental studies to date have focused on retrieval performance, but very few on conflation performance. The process of normalization we used involved a linguistic toolbox that allowed us to construct, through graphic interfaces, electronic dictionaries represented i...

  13. Engine Oil Condition Monitoring Using High Temperature Integrated Ultrasonic Transducers

    OpenAIRE

    Jeff Bird; Cheng-Kuei Jen; Zhigang Sun; Pierre Sammut; Brian Galeote; Makiko Kobayashi; Kuo-Ting Wu; Nezih Mrad

    2011-01-01

    The present work contains two parts. In the first part, high temperature integrated ultrasonic transducers (IUTs) made of thick piezoelectric composite films, were coated directly onto lubricant oil supply and sump lines of a modified CF700 turbojet engine. These piezoelectric films were fabricated using a sol-gel spray technology. By operating these IUTs in transmission mode, the amplitude and velocity of transmitted ultrasonic waves across the flow channel of the lubricant oil in supply and...

  14. Acoustic Radiation from Transducer in Semi-infinite Fluid Medium

    Science.gov (United States)

    2016-06-07

    IIIII v 841087 121CilN ACOUSTIC RADIATION F~ TRANSDUCER IN SFMI-INFINITE FLUID MEDIUM Date: June 19, 1984 Prepared by: Jay ant S. Patel...1. REPORT DATE 19 JUN 1984 2. REPORT TYPE Technical Memo 3. DATES COVERED 19-06-1984 to 19-06-1984 4. TITLE AND SUBTITLE Acoustic Radiation ...Technical Menorandum TM No. 841087 ACOUSTIC RADIATION FROM TRANSOOCER IN SEMI-INFINITE FliJID MEDIUM Date: June 19, 1984 Prepared by: Jayant s. Patel

  15. Analytical and Experimental Issues in Ni-Mn-Ga Transducers

    Science.gov (United States)

    2003-01-01

    tests seen in Figure 10 can cause test repeatability problems due to heat issues in the sample, transducer, and amplifiers. However, with adequate...layered martensitic phase,” Appl. Phys. Let. 80, pp. 1746–1749, March 2002. 5. V. Pecharsky and J. K.A. Gshneidner, “Giant magnetocaloric effect in...giant magnetocaloric effect for magnetic refrigeration from 20 to 290 k,” Applied Physics Letters 70, pp. 3299–3301, June 1997. 7. A. Malla, M

  16. Tonpilz Underwater Acoustic Transducer Integrating Lead-free Piezoelectric Material

    Science.gov (United States)

    Rouffaud, Rémi; Granger, Christian; Hladky-Hennion, Anne-Christine; Thi, Mai Pham; Levassort, Franck

    A Tonpilz transducer based on lead-free piezoelectric material was fabricated, modeled and characterized. The stack is composed of two rings of doped BaTiO3. This composition was initially chosen due to good electromechanical performance (kt at 40%) and high mechanical quality factor (Qm over 500). Comparison of the displacement at the center of the head mass was performed with a PZT-based Tonpilz with the same design for a center frequency at 22 kHz.

  17. Finite element analysis of hysteresis effects in piezoelectric transducers

    Science.gov (United States)

    Simkovics, Reinhard; Landes, Hermann; Kaltenbacher, Manfred; Hoffelner, Johann; Lerch, Reinhard

    2000-06-01

    The design of ultrasonic transducers for high power applications, e.g. in medical therapy or production engineering, asks for effective computer aided design tools to analyze the occurring nonlinear effects. In this paper the finite-element-boundary-element package CAPA is presented that allows to model different types of electromechanical sensors and actuators. These transducers are based on various physical coupling effects, such as piezoelectricity or magneto- mechanical interactions. Their computer modeling requires the numerical solution of a multifield problem, such as coupled electric-mechanical fields or magnetic-mechanical fields as well as coupled mechanical-acoustic fields. With the reported software environment we are able to compute the dynamic behavior of electromechanical sensors and actuators by taking into account geometric nonlinearities, nonlinear wave propagation and ferroelectric as well as magnetic material nonlinearities. After a short introduction to the basic theory of the numerical calculation schemes, two practical examples will demonstrate the applicability of the numerical simulation tool. As a first example an ultrasonic thickness mode transducer consisting of a piezoceramic material used for high power ultrasound production is examined. Due to ferroelectric hysteresis, higher order harmonics can be detected in the actuators input current. Also in case of electrical and mechanical prestressing a resonance frequency shift occurs, caused by ferroelectric hysteresis and nonlinear dependencies of the material coefficients on electric field and mechanical stresses. As a second example, a power ultrasound transducer used in HIFU-therapy (high intensity focused ultrasound) is presented. Due to the compressibility and losses in the propagating fluid a nonlinear shock wave generation can be observed. For both examples a good agreement between numerical simulation and experimental data has been achieved.

  18. Progress towards developing neutron tolerant magnetostrictive and piezoelectric transducers

    Energy Technology Data Exchange (ETDEWEB)

    Reinhardt, Brian [Pennsylvania State Univ., University Park, PA (United States). Dept. of Engineering Science and Mechanics; Tittmann, Bernhard [Pennsylvania State Univ., University Park, PA (United States). Dept. of Engineering Science and Mechanics; Rempe, Joy [Idaho National Lab. (INL), Idaho Falls, ID (United States); Daw, Joshua [Idaho National Lab. (INL), Idaho Falls, ID (United States); Kohse, Gordon [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States). MIT Nuclear Reactor Lab.; Carpenter, David [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States). MIT Nuclear Reactor Lab.; Ames, Micheal [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States). MIT Nuclear Reactor Lab.; Ostrovsky, Yakov [MIT (Massachusetts Inst. of Technology), Cambridge, MA (United States). MIT Nuclear Reactor Lab.; Ramuhalli, Pradeep [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Montgomery, Robert [Pacific Northwest National Lab. (PNNL), Richland, WA (United States); Chien, Hualte [Argonne National Lab. (ANL), Argonne, IL (United States); Wernsman, Bernard [Bettis Atomic Power Lab. (BAPL), West Mifflin, PA (United States). Bechtel Marine Propulsion Corp.

    2014-07-01

    Current generation light water reactors (LWRs), sodium cooled fast reactors (SFRs), small modular reactors (SMRs), and next generation nuclear plants (NGNPs) provide harsh environments in and near the core that can severely test material performance and limit their operational life. To address this issue, several Department of Energy Office of Nuclear Energy (DOE-NE) research programs are evaluating the long duration radiation performance of fuels and materials. In To reduce the amount of Material and Test Reactor (MTR) irradiations required, DOE is also funding development of enhanced instrumentation that will be able to obtain data, with unprecedented accuracy and resolution, that are required to validate new multi-scale multiphysics modeling tools . It is not feasible to obtain such data with the current state of instrumentation technology. To address this need, PSU and collaborators have started an experiment to test the potential for utilizing ultrasonic instruments in-pile. Ultrasonic sensors must be resistant to high neutron flux, high gamma radiation, and high temperature. PSU and collaborators have designed, fabricated, and started to irradiate piezoelectric and magnetostrictive transducers designed to perform in such harsh environments. Three piezoelectric transducers were fabricated with aluminum nitride, zinc oxide, and bismuth titanate as the active element. The transducers are coupled kovar and aluminum waveguides of which pulse-echo ultrasonic measurements are made in-situ. Two magnetostrictive transducers were fabricated with Remendur and Arnokrome as the active elements. These devices will be pulsed and monitored in-situ. (1) Selection of candidate sensor materials as well as optimization of test assembly parameters (2) High temperature benchmark testing and (3) initial data from the irradiation will be reported.

  19. Epidemiology of Needle-Stick Injuries in Mangalore

    Directory of Open Access Journals (Sweden)

    Prakash

    2012-08-01

    Full Text Available ABSTRACT: BACKGROUND: Health care workers (HCWs are always at greater r isk of infection by needle- stick injuries (NSIs owing to their greater handli ng of sharps in various situations. OBJECTIVE: The main objective was to review the epidemiology of NSIs among HCWs, and describe the circumstances under which these injuries occurred. METHODS: A questionnaire based, cross sectional study was done during the month of Januar y 2008 at 3 Kasturba Medical College (KMC institutions, Mangalore. The data was computed and analyzed using SPSS statistical package. RESULTS: During the study period 272 HCWs were self administ ered questionnaire/interviewed and 102 HCWs reported (37. 5% incidents of injuries with needles during the past 12 months. Doctors were the most fre quent victims (64.7%, followed by waste disposal staff (25.5% and Nurses (7.8%. More than 50% of the victims had more than 3 pricks in the last 12 months. Hospital wards and operation t heatre were the major locations of needle- stick incidents (31.4% each. Most commonly, injuri es occurred during suturing (41.1% and when using solid bore or suturing needle (47.1%. M ajority of them neither reported the injury (60.8% nor received post-exposure prophylaxis (70.6% . Patient tested sero-negative was the major reason for not reporting the injury. Governme nt hospital staff and waste disposal staff had significantly higher chance of NSI when compared to their counterparts. Conclusions: The study re-emphasized the importance of continued educ ational and prevention programmes for HCWs in the prevention of needle-stick injuries.

  20. New real time needle segmentation technique using grayscale Hough transformation

    Science.gov (United States)

    Qiu, Wu; Zhou, Hua; Ding, Mingyue; Zhang, Songgeng

    2007-12-01

    Real-time needle segmentation and tracking is very important in image-guided surgery, biopsy, and therapy. In this paper, we described an automated technique to provide real-time needle segmentation from a sequence of 2-D ultrasound images for the use of guidance of a needle to the target in soft tissues. The Hough transform is used to find straight lines or analytic curves in binary image. Hough transform is applied usually to binary images. Hence one needs to convert, initially, the gray level image to a binary one (through thresholding, edge detection, or thinning) in order to apply the HT. While in the process of binarization, some information about line segments in the image may be lost when an inappropriate threshold is used. Gray-Scale Hough Transform can detect the line without binarization. Unfortunately, its high computational cost often prevents it from being applied in real-time applications without the help of specially designed hardware. In this paper, we proposed a needle segmentation technique based on a real-time gray-scale Hough transform. It is composed of an improved Gray Hough Transformation and a coarse-fine search strategy. Furthermore, the RTGHT (Real-Time Gray-Scale Hough Transform) technique is evaluated by patient breast biopsy images. Experiments with patient breast biopsy ultrasound (US) image sequences showed that our approach can segment the biopsy needle in real time (i.e., less than 60 ms) with the angular rms error of about 1° and the position rms error of about 0.5 mm an affordable PC computer without the help of specially designed hardware.

  1. Focused intravascular ultrasonic probe using dimpled transducer elements.

    Science.gov (United States)

    Chen, Y; Qiu, W B; Lam, K H; Liu, B Q; Jiang, X P; Zheng, H R; Luo, H S; Chan, H L W; Dai, J Y

    2015-02-01

    High-frequency focused intravascular ultrasonic probes were fabricated in this study using dimple technique based on PMN-PT single crystal and lead-free KNN-KBT-Mn ceramic. The center frequency, bandwidth, and insertion loss of the PMN-PT transducer were 34 MHz, 75%, and 22.9 dB, respectively. For the lead-free probe, the center frequency, bandwidth, and insertion loss were found to be 40 MHz, 72%, and 28.8 dB, respectively. The ultrasonic images of wire phantom and vessels with good resolution were obtained to evaluate the transducer performance. The -6 dB axial and lateral resolutions of the PMN-PT probe were determined to be 58 μm and 131 μm, respectively. For the lead-free probe, the axial and lateral resolutions were found to be 44 μm and 125 μm, respectively. These results suggest that the mechanical dimpling technique has good potential in preparing focused transducers for intravascular ultrasound applications.

  2. Measurement of trocar insertion force using a piezoelectric transducer.

    Science.gov (United States)

    Ng, Pui Shan; Sahota, Daljit Singh; Yuen, Pong Mo

    2003-11-01

    We attempted to establish a model to measure the force required for trocar insertion at laparoscopy. A 3-cm, circular transducer was constructed from piezoresistive material that changes its impedance as force is exerted on its surface. The transducer is connected by an interface box to a personal computer to record surface contact pressure digitally (pressure = force/area) profile continuously during trocar insertion. Each subject had three trocars inserted: a 10-mm trocar at the umbilicus after creation of pneumoperitoneum, and 5-mm trocars at corresponding sites on the left and right sides of the lower abdomen. All insertions were performed by the same operator using reusable trocar with a conical tip. Each subject acted as her own control. Recordings were successfully obtained from eight women. There was no instance of transducer failure. The mean (SE) peak contact surface pressure for the 10-mm and 5-mm left and right trocars were 5.3 (0.32), 6.4 (0.51), and 6.81 (0.27) pounds/square inch, respectively. Placement of the 10-mm trocar required less insertion force than placement of the 5-mm trocars. There was a strong negative correlation (r = -0.97, p trocar.

  3. An Analysis of Transducer Mass Loading Effect Inshaker Testing

    Directory of Open Access Journals (Sweden)

    A. D. Karle

    2014-06-01

    Full Text Available Modal Analysis has been a developing science in the experimental evaluation of the dynamic properties of the structures. Frequency Response Function (FRF is one of the major steps in modal analysis. Measured frequency response functions (FRFs are used to extract modal parameters. It is also known that the accuracy and the reliability of various analyses using the measured FRFs depend strongly on the quality of measured data. It is well known that the quality of measured frequency response functions (FRFs is adversely affected by many factors, most significant sources being noise and systematic errors like mass loading effects of transducers. A transducer mounted on a vibrating system changes the dynamics of the structure due to the addition of extra mass and introduces errors into measured FRFs. One problem with this is the production of unrealistic results, which cause the measured resonant frequencies to be less than the correct values. These errors also lead to incorrect prediction of modal parameters. In many situations, the mass loading effect is ignored in the analytical and experimental process, based on a usual assumption that the transducer mass is negligible compared to that of the structure under test. However, when light-weighted structures are investigated, this effect can be significant.

  4. Dual-Frequency Piezoelectric Transducers for Contrast Enhanced Ultrasound Imaging

    Directory of Open Access Journals (Sweden)

    K. Heath Martin

    2014-11-01

    Full Text Available For many years, ultrasound has provided clinicians with an affordable and effective imaging tool for applications ranging from cardiology to obstetrics. Development of microbubble contrast agents over the past several decades has enabled ultrasound to distinguish between blood flow and surrounding tissue. Current clinical practices using microbubble contrast agents rely heavily on user training to evaluate degree of localized perfusion. Advances in separating the signals produced from contrast agents versus surrounding tissue backscatter provide unique opportunities for specialized sensors designed to image microbubbles with higher signal to noise and resolution than previously possible. In this review article, we describe the background principles and recent developments of ultrasound transducer technology for receiving signals produced by contrast agents while rejecting signals arising from soft tissue. This approach relies on transmitting at a low-frequency and receiving microbubble harmonic signals at frequencies many times higher than the transmitted frequency. Design and fabrication of dual-frequency transducers and the extension of recent developments in transducer technology for dual-frequency harmonic imaging are discussed.

  5. Efficient Driving of Piezoelectric Transducers Using a Biaxial Driving Technique.

    Directory of Open Access Journals (Sweden)

    Samuel Pichardo

    Full Text Available Efficient driving of piezoelectric materials is desirable when operating transducers for biomedical applications such as high intensity focused ultrasound (HIFU or ultrasound imaging. More efficient operation reduces the electric power required to produce the desired bioeffect or contrast. Our preliminary work [Cole et al. Journal of Physics: Condensed Matter. 2014;26(13:135901.] suggested that driving transducers by applying orthogonal electric fields can significantly reduce the coercivity that opposes ferroelectric switching. We present here the experimental validation of this biaxial driving technique using piezoelectric ceramics typically used in HIFU. A set of narrow-band transducers was fabricated with two sets of electrodes placed in an orthogonal configuration (following the propagation and the lateral mode. The geometry of the ceramic was chosen to have a resonance frequency similar for the propagation and the lateral mode. The average (± s.d. resonance frequency of the samples was 465.1 (± 1.5 kHz. Experiments were conducted in which each pair of electrodes was driven independently and measurements of effective acoustic power were obtained using the radiation force method. The efficiency (acoustic/electric power of the biaxial driving method was compared to the results obtained when driving the ceramic using electrodes placed only in the pole direction. Our results indicate that the biaxial method increases efficiency from 50% to 125% relative to the using a single electric field.

  6. Performance analysis of ultrasono-therapy transducer with contact detection.

    Science.gov (United States)

    Moreno, Eduardo; González, Gilberto; Leija, Lorenzo; Rodríguez, Orlando; Castillo, Martha; Fuentes, Martín

    2003-06-01

    The performance of ultrasono-therapy transducer with contact detection by using the impedance phase change is described. Usually a therapy transducer is designed with a lambda/2 frontal plate glued to a PZT-4 piezoceramic. This plate ensures a good mechanical protection of the piezoceramic with a corresponding high-transmission energy. Normally this transducer is operated at the minimum at the frequency of the impedance module of its input electric impedance, but this operation point is affected by the shift caused by the expected temperature increase. This shift could be higher than the narrow bandwidth presented. As a result we obtain a decrease in the power level for medical treatment. Usually it is designed electronic drivers with automatic control that follow the frequency change, but the relatively narrow bandwidth introduces difficulty in the design. Another frequency operation point is presented here and analyzed using the criteria of the maximum of the impedance phase with a wider bandwidth than in the previous case. Simulation with mechanical losses are presented with experimental results that show the convenience of this criteria for practical application.

  7. Deconvolution based photoacoustic reconstruction for directional transducer with sparsity regularization

    Science.gov (United States)

    Moradi, Hamid; Tang, Shuo; Salcudean, Septimiu E.

    2016-03-01

    We define a deconvolution based photoacoustic reconstruction with sparsity regularization (DPARS) algorithm for image restoration from projections. The proposed method is capable of visualizing tissue in the presence of constraints such as the specific directivity of sensors and limited-view Photoacoustic Tomography (PAT). The directivity effect means that our algorithm treats the optically-generated ultrasonic waves based on which direction they arrive at the transducer. Most PA image reconstruction methods assume that sensors have omni-directional response; however, in practice, the sensors show higher sensitivity to the ultrasonic waves coming from one specific direction. In DPARS, the sensitivity of the transducer to incoming waves from different directions are considered. Thus, the DPARS algorithm takes into account the relative location of the absorbers with respect to the transducers, and generates a linear system of equations to solve for the distribution of absorbers. The numerical conditioning and computing times are improved by the use of a sparse Discrete Fourier Transform (DCT) representation of the distribution of absorption coefficients. Our simulation results show that DPARS outperforms the conventional Delay-and-Sum reconstruction method in terms of CNR and RMS errors. Experimental results confirm that DPARS provides images with higher resolution than DAS.

  8. Energy harvesting potential of tuned inertial mass electromagnetic transducers

    Science.gov (United States)

    Asai, Takehiko; Araki, Yoshikazu; Ikago, Kohju

    2017-02-01

    The demand for developing renewable energy technologies has been growing in today's society. As one of promising renewable energy sources, large-scale energy harvesting from structural vibrations employing electromagnetic transducers has recently been proposed and considerable effort has been devoted to increase the power generation capability. In this paper, we introduce the mechanism of a tuned inertial mass electromagnetic transducer (TIMET), which can absorb vibratory energy more efficiently by tuning the parameters to adjust the system. Then we propose a new vibratory energy harvester with the TIMET and determine the parameter values for the device with a simple static admittance (SA) control law to maximize the energy harvested from a stationary stochastic disturbance. To investigate the energy harvesting potential of the TIMET further, the performance-guaranteed (PG) control and the LQG control proposed in the literature are applied as well. Then the numerical simulation studies are carried out and the effectiveness of the proposed energy harvester is examined by comparing the traditional electromagnetic transducers.

  9. A proposed magnetic digital temperature transducer, volume 1

    Science.gov (United States)

    Collier, T. E.; Tchernev, D. I.; Hartwig, W. H.

    1972-01-01

    A study has been made of the feasibility of using the discontinuous permeability versus temperature characteristics of some magnetic materials for a digital temperature transducer and a thermally controlled ON-OFF switch. Simple logic converts the number of output pulse to a digital word recognizable by the system. Efforts have been concentrated on materials with Curie temperatures between 0 and 100 C. One compound has the composition Mn(5-x)Fe(x)Ge3 where the amount of iron determines the transition temperature. The other compound is Ni-Zn ferrite and has the compositon Ni(1-x)Zn(x)Fe(1.95)O4 where the nickel: zinc ratio determines the transition temperature. A detailed report of materials prepared is presented. Toroidal inductors of the material have been constructed and the change in inductance with temperature measured. In view of these initial measurements, it is felt that a transducer utilizing the permeability versus temperature characteristics of these materials has promise as a reliable and sensitive solid state digital temperature transducer.

  10. Tunable-angle wedge transducer for improved acoustophoretic control in a microfluidic chip

    DEFF Research Database (Denmark)

    Iranmanesh, I.; Barnkob, Rune; Bruus, Henrik;

    2013-01-01

    coupling angle, and transducer actuation method (single-frequency actuation or frequency-modulation actuation). The energy-density analysis is based on measuring the transmitted light intensity through a microfluidic channel filled with a suspension of 5 µm diameter beads and the results with the tunable...... uniform particle patterns with average acoustic energy densities comparable to those obtained using single-frequency actuation.......We present a tunable-angle wedge ultrasound transducer for improved control of microparticle acoustophoresis in a microfluidic chip. The transducer is investigated by analyzing the pattern of aligned particles and induced acoustic energy density while varying the transducer geometry, transducer...

  11. Test-Driven Development of IEEE 1451 Transducer Services and Application

    Directory of Open Access Journals (Sweden)

    S. Ranđić

    2012-06-01

    Full Text Available IEEE 1451 standard defines the methods of integrating smart transducers into communicating networks. Interface between a user application and a field of transducers, known as Transducer Services API is defined by standrad IEEE 1451.0. This paper presents the use of Test- Driven Design (TDD in developing methods for accessing transducer services using Transducer Services API and developing web applications which access this services over the network. The characteristics of TDD and its benefits are presented and the way of realization for one method is shown using Java and JUnit framework to run tests.

  12. The Clinical study on the change of pain after needle acupuncture and needle acupuncture combined herbal acupuncture therapy in the musculoskeletal disorder

    OpenAIRE

    2005-01-01

    Objective : This study was performed to compare needle acupuncture combined herbal acupuncture therapy with only needle acupuncture therapy in VAS and pain threshold. Methods : We used pressure algometer to evaluate the change of pain threshold before and after treatment. The numberical value of pressure algometer is obtained twice and averaged by identical acupuncturist. Visual analogue scale(VAS) was used to estimate the efficacy of needle acupuncture combined herbal acupuncture therapy....

  13. Effects of irrigation, fertilization and drought on the occurrence of Lophodermium piceae in Picea abies needles

    Energy Technology Data Exchange (ETDEWEB)

    Lehtijaervi, Asko; Barklund, Pia [Swedish Univ. of Agricultural Sciences, Uppsala (Sweden). Dept. of Forest Mycology and Pathology

    1999-08-01

    Effects of irrigation, drought and fertilization on the frequency of the fungal endophyte Lophodermium piceae in green needles was assessed in a 30-year-old experimental stand of Picea abies in southern Sweden. Frequencies of needles with L. piceae were lower in irrigation and ammonium sulphate fertilization treatments than in the control. Drought treatment frequencies were similar to the control. Needles were susceptible to colonization for at least 3 years; colonization increased with needle age. The results indicate that the increased availability of water to the root system as well as ammonium sulphate fertilization indirectly delays colonization of needles by L. piceae 21 refs, 3 figs, 2 tabs

  14. Variability in needle traits of Pinus mugo Turra in the Ukrainian Carpathians

    Directory of Open Access Journals (Sweden)

    Krystyna Boratyńska

    2014-01-01

    Full Text Available Two-year-old needles were collected from 131 trees in 4 localities in the Eastern Carpathians in Ukraine. The needles were analysed in respect to 15 morphological and anatomical traits. The most stable appear to be needle width and thickness, and the ratio of needle thickness to width, while the distance between vascular bundles, Marcet's coefficient and number of resin canals were the most variable. Some of the analysed populations differ significantly from each other in the thickness of epidermal cells, number of resin canals and numbers of stomata on adaxial and abaxial surfaces of the needle.

  15. Needle Migration to the Heart: An Unusual Association of Hemodialysis and Cardiovascular Morbidity.

    Science.gov (United States)

    Honikman, Rafael; Chikwe, Joanna; Tokita, Joji Erik; Mittnacht, Alexander J C

    2015-10-15

    In this report, we present a unique complication of hemodialysis: the hemodialysis access needle was lost into an arteriovenous fistula. The event went unnoticed for several months. The needle eventually migrated into the right ventricle, requiring an operative retrieval. Loss of the needle was likely unrecognized because of the use of a retracting safety cannula that conceals the needle within a sheath after removal. This case highlights a rare and potentially serious complication of hemodialysis access, demonstrates a possible hazard of retracting safety needles, and reviews the management of foreign bodies that have migrated into the heart.

  16. Numerical Modelling of Mutual Effect among Nearby Needles in a Multi-Needle Configuration of an Atmospheric Air Dielectric Barrier Discharge

    Directory of Open Access Journals (Sweden)

    Xiaoxing Zhang

    2012-05-01

    Full Text Available A numerical study has been conducted to understand the mutual effect among nearby needles in a multi-needle electrode dielectric barrier discharge. In the present paper, a fluid-hydrodynamic model is adopted. In this model, the mutual effect among nearby needles in a multi-needle configuration of an atmospheric air dielectric barrier discharge are investigated using a fluid-hydrodynamic model including the continuity equations for electrons and positive and negative ions coupled with Poisson’s equation. The electric fields at the streamer head of the middle needle (MN and the side needles (SNs in a three-needle model decreased under the influence of the mutual effects of nearby needles compared with that in the single-needle model. In addition, from the same comparison, the average propagation velocities of the streamers from MN and SNs, the electron average energy profile of MN and SNs (including those in the streamer channel, at the streamer head, and in the unbridged gap, and the electron densities at the streamer head of the MN and SNs also decreased. The results obtained in the current paper agreed well with the experimental and simulation results in the literature.

  17. Development of an omni-directional shear-horizontal wave magnetostrictive patch transducer for plates.

    Science.gov (United States)

    Seung, Hong Min; Kim, Hoe Woong; Kim, Yoon Young

    2013-09-01

    As an effective tool to inspect large plates, omni-directional guided wave transducers have become more widely used to form phased-array inspection systems. While omni-directional Lamb wave transducers have been successfully utilized in the systems, omni-directional Shear-Horizontal (SH) wave transducers have not been investigated. In this paper, we propose an omni-directional SH magnetostrictive patch transducer that consists of an annular magnetostrictive patch, a toroidal coil and a permanent magnet. After presenting the unique configuration of the proposed transducer and its working principle, the omni-directivity of the developed transducer is verified through simulations and experiments conducted in an aluminum plate. The frequency characteristics of the proposed transducer depending on the patch size are also investigated as the underlying reference data for future construction of an SH phased-array system.

  18. Analytical modeling and experimental validation of a V-shape piezoelectric ultrasonic transducer

    Science.gov (United States)

    Li, Xiaoniu; Yao, Zhiyuan

    2016-07-01

    In this paper, an analytical model of a V-shape piezoelectric ultrasonic transducer is presented. The V-shape piezoelectric ultrasonic transducer has been widely applied to the piezoelectric actuator (ultrasonic motor), ultrasonic aided fabrication, sensor, and energy harvesting device. The V-shape piezoelectric ultrasonic transducer consists of two Langevin-type transducers connected together through a coupling point with a certain coupling angle. Considering the longitudinal and lateral movements of a single beam, the symmetrical and asymmetrical modals of the V-shape piezoelectric ultrasonic transducer are calculated. By using Hamilton-Lagrange equations, the electromechanical coupling model of the V-shape piezoelectric ultrasonic transducer is proposed. The influence of the coupling angle and cross-section on modal characteristics and electromechanical coupling coefficient are analyzed by the analytical model. A prototype of the V-shape piezoelectric ultrasonic transducer is fabricated, and the results of the experiments are in good agreement with the analytical model.

  19. Design of an Underwater Tonpilz Transducer with 1-3 Piezocomposite Materials

    Science.gov (United States)

    Pei, Da Lie; Roh, Yongrae

    2008-05-01

    An underwater Tonpilz transducer is designed with 1-3 piezocomposite materials to overcome the limitations of conventional piezoceramic transducers. With the finite element method (FEM), the variation of the resonance frequency, bandwidth and radiated sound pressure was analyzed in relation to the structural variables of the transducer. Through statistical multiple regression analysis of the finite element analysis (FEA) results, functional forms of the transducer performance are derived in terms of the design variables. Through the constrained minimization with the derived functions, the optimal structure of the transducer is determined to provide the highest sound pressure level at a given resonant frequency over a pre-determined frequency range. The validity of the optimization is confirmed by comparing the performance of the designed piezocomposite transducer with that of a conventional piezoceramic transducer.

  20. Enhanced needle localization in ultrasound using beam steering and learning-based segmentation.

    Science.gov (United States)

    Hatt, Charles R; Ng, Gary; Parthasarathy, Vijay

    2015-04-01

    Segmentation of needles in ultrasound images remains a challenging problem. In this paper, we introduce a machine learning-based method for needle segmentation in 2D beam-steered ultrasound images. We used a statistical boosting approach to train a pixel-wise classifier for needle segmentation. The Radon transform was then used to find the needle position and orientation from the segmented image. We validated our method with data from ex vivo specimens and clinical nerve block procedures, and compared the results to those obtained using previously reported needle segmentation methods. Results show improved localization success and accuracy using the proposed method. For the ex vivo datasets, assuming that the needle orientation was known a priori, the needle was successfully localized in 86.2% of the images, with a mean targeting error of 0.48mm. The robustness of the proposed method to a lack of a priori knowledge of needle orientation was also demonstrated. For the clinical datasets, assuming that the needle orientation was closely aligned with the beam steering angle selected by the physician, the needle was successfully localized in 99.8% of the images, with a mean targeting error 0.19mm. These results indicate that the learning-based segmentation method may allow for increased targeting accuracy and enhanced visualization during ultrasound-guided needle procedures.

  1. Practice and Evaluation: Management of Acupunc-ture Needle Disinfection and Sterilization

    Institute of Scientific and Technical Information of China (English)

    Hui Chen; Hao Huang

    2015-01-01

    Objective: To investigate the necessity and importance of enhancing the sterilization management of acupuncture needles. Methods: Traditionally, acupuncture needles were cleaned manually without thermal disinfec-tion, which often caused needle-stick injuries. To solve the problems, a special cleaning case for acupuncture needles was designed and built to help achieve optimization of the processing flow if the case is used correctly in the process of recycling, cleaning, and package checking. Results: Closed treatment of acupuncture needles reduced the percentage of needle-stick injuries to zero, and centralized management raised patients' satisfaction rate from 93% to 98%. Conclusions: Effective sterilization of acupuncture needles is a precondition for the safe treat-ment of patients. Optimization of the processing flow can ensure the safety of medical personnel and patients; safety is stipulated by relevant regulationsconcerning sterilization and disinfection standards.

  2. Silicon Needles Fabricated by Highly Selective Anisotropic Dry Etching and Their Field Emission Current Characteristics

    Science.gov (United States)

    Kanechika, Masakazu; Mitsushima, Yasuichi

    2000-12-01

    A new process to fabricate a silicon needle, whose tip radius is about 5 nm and aspect ratio is about 7, was developed. The silicon needles were fabricated by highly selective anisotropic dry etching. The etching mask was oxygen precipitation, which was formed by nitrogen ion implantation and the subsequent oxidation. The process is simple enough to be integrated with complementary metal-oxide-semiconductor (CMOS) circuits. The density of the silicon needle can be controlled by adjusting the dose for nitrogen ion implantation. The position of the silicon needle can be controlled by adjusting the position for nitrogen ion implantation, because silicon needles are formed only in the nitrogen ion implantation area. Furthermore, using these silicon needles as micro emitters, a field emission diode was fabricated. The Fowler-Nordheim plot shows that the field around the tip of the silicon needles was highly enhanced.

  3. [Research thoughts and methodology on efficacy specificity of needling and moxibustion methods based upon data mining].

    Science.gov (United States)

    Jia, Chun-sheng; Li, Xiao-feng; Wang, Jian-ling; Xu, Jing

    2011-02-01

    The method for needling and moxibustion is an indispensable component of acupuncturology. In clinical practice of acupuncture and moxibustion, efficacy specificity of different needling and moxibustion methods for different clinical conditions or different phases of a disease exists objectively, which is in a close relation with the results of clinical interventions. Starting with the correlation between the efficacy specificity of different needling and moxibustion methods and different clinical conditions or syndromes, the authors of the present paper put forward to collect abundant literature on needling and moxibustion methods, extract and analyze standard formats of information, establish literature database on needling and moxibustion methods and then design literature data application platform. On the basis of those mentioned above, a data mining model of needling and moxibustion methods will be established for revealing the potential knowledge and regularities about application of needling and moxibustion methods from the related abundant fuzzy and incomplete literature data according to data analysis and designed research program on efficacy specificity.

  4. Using rotation for steerable needle detection in 3D color-Doppler ultrasound images.

    Science.gov (United States)

    Mignon, Paul; Poignet, Philippe; Troccaz, Jocelyne

    2015-08-01

    This paper demonstrates a new way to detect needles in 3D color-Doppler volumes of biological tissues. It uses rotation to generate vibrations of a needle using an existing robotic brachytherapy system. The results of our detection for color-Doppler and B-Mode ultrasound are compared to a needle location reference given by robot odometry and robot ultrasound calibration. Average errors between detection and reference are 5.8 mm on needle tip for B-Mode images and 2.17 mm for color-Doppler images. These results show that color-Doppler imaging leads to more robust needle detection in noisy environment with poor needle visibility or when needle interacts with other objects.

  5. An effective algorithm for needle tip displacement compensation in robot-assisted percutaneous surgery

    Institute of Scientific and Technical Information of China (English)

    Sun Yinshan; Wu Dongmei; Du Zhijiang; Sun Lining

    2010-01-01

    This paper presents an automatic compensation algorithm for needle tip displacement in order to keep the needle tip always fixed at the skin entry point in the process of needle orientation in robot-assisted percutaneous surgery.The algorithm, based on a two-degree-of-freedom (2-DOF) robot wrist (not the mechanically constrained remote center of motion (RCM) mechanism) and a 3-DOF robot arm, firstly calculates the needle tip displacement caused by rotational motion of robot wrist in the arm coordinate frame using the robotic forward kinematics, and then inversely compensates for the needle tip displace-ment by real-time Cartesian motion of robot arm.The algorithm achieves the function of the RCM and eliminates many mechanical and virtual constraints caused by the RCM mechanism.Experimental result demonstrates that the needle tip displacement is within 1 mm in the process of needle orientation.

  6. Toward robotic needle steering in lung biopsy: a tendon-actuated approach

    Science.gov (United States)

    Kratchman, Louis B.; Rahman, Mohammed M.; Saunders, Justin R.; Swaney, Philip J.; Webster, Robert J., III

    2011-03-01

    Needle tip dexterity is advantageous for transthoracic lung biopsies, which are typically performed with rigid, straight biopsy needles. By providing intraoperative compensation for trajectory error and lesion motion, tendon-driven biopsy needles may reach smaller or deeper nodules in fewer attempts, thereby reducing trauma. An image-guided robotic system that uses these needles also has the potential to reduce radiation exposure to the patient and physician. In this paper, we discuss the design, workflow, kinematic modeling, and control of both the needle and a compact and inexpensive robotic prototype that can actuate the tendon-driven needle for transthoracic lung biopsy. The system is designed to insert and steer the needle under Computed Tomography (CT) guidance. In a free-space targeting experiment using a discrete proportional control law with digital camera feedback, we show a position error of less than 1 mm achieved using an average of 8.3 images (n=3).

  7. Interferon and the fear of needles: a case report.

    Science.gov (United States)

    López, Maria; Moreno, Laura; Dosal, Angelina; Pujol, Marta Maria; Vergara, Mercedes; Gil, Montserrat

    2011-01-01

    The treatment of viral hepatitis C infection uses a combination of pegylated interferon and ribavirin. Psychological preparation of the patient is vital to ensure adherence to the treatment. In our center, the nurse prepares this treatment according to an established educative protocol; however, some patients have special needs that require individualized attention. One such situation observed by the nurse is that the patients frequently admit to the fear of needle puncture (the peginterferon treatment is administered subcutaneously) and are unable to inject themselves. We describe a representative case and the care plan to manage the patient's fear so that the patient acquires confidence in his or her ability to self-inject. This facilitates autonomy and coresponsibility for the treatment, and the nurse can develop care approaches to combat the patient's fear of needles.

  8. Needles of Pinus halepensis as biomonitors of bioaerosol emissions.

    Science.gov (United States)

    Galès, Amandine; Latrille, Eric; Wéry, Nathalie; Steyer, Jean-Philippe; Godon, Jean-Jacques

    2014-01-01

    We propose using the surface of pine trees needles to biomonitor the bioaerosol emissions at a composting plant. Measurements were based on 16S rRNA gene copy numbers of Saccharopolyspora rectivirgula, a bioindicator of composting plant emissions. A sampling plan was established based on 29 samples around the emission source. The abundance of 16S rRNA gene copies of S. rectivirgula per gram of Pinus halepensis needles varied from 104 to 102 as a function of the distance. The signal reached the background level at distances around the composting plant ranging from 2 km to more than 5.4 km, depending on the local topography and average wind directions. From these values, the impacted area around the source of bioaerosols was mapped.

  9. Existence of needle crystals in local models of solidification

    Science.gov (United States)

    Langer, J. S.

    1986-01-01

    The way in which surface tension acts as a singular perturbation to destroy the continuous family of needle-crystal solutions of the steady-state growth equations is analyzed in detail for two local models of solidification. All calculations are performed in the limit of small surface tension or, equivalently, small velocity. The basic mathematical ideas are introduced in connection with a quasilinear, isotropic version of the geometrical model of Brower et al., in which case the continuous family of solutions dissappears completely. The formalism is then applied to a simplified boundary-layer model with an anisotropic kinetic attachment coefficient. In the latter case, the solvability condition for the existence of needle crystals can be satisfied whenever the coefficient of anisotropy is arbitrarily small but nonzero.

  10. Stimulated jitter with concentric needle in 42 myasthenia gravis patients

    Directory of Open Access Journals (Sweden)

    João Aris Kouyoumdjian

    2013-04-01

    Full Text Available Objective: To estimate jitter parameters in myasthenia gravis in stimulated frontalis and extensor digitorum muscles using the concentric needle electrode. Methods: Forty-two confirmed myasthenia gravis patients, being 22 males (aged 45.6±17.2 years-old were studied. Jitter was expressed as the mean consecutive difference (MCD. Results: MCD in extensor digitorum was 61.6 µs (abnormal in 85.7% and in frontalis 57.3 µs (abnormal in 88.1%. Outliers represented 90.5% for extensor digitorum and 88.1% for frontalis. At least one jitter parameter was abnormal in 90.5% of the combined studies. Acetylcholine receptor antibody was abnormal in 85.7% of the cases. Conclusions: Stimulated jitter recordings measured from muscles using concentric needle electrode can be used for myasthenia gravis diagnosis with high sensitivity. Extensive normative studies are still lacking and, therefore, borderline findings should be judged with great caution.

  11. Silica needle template fabrication of metal hollow microneedle arrays

    Science.gov (United States)

    Zhu, M. W.; Li, H. W.; Chen, X. L.; Tang, Y. F.; Lu, M. H.; Chen, Y. F.

    2009-11-01

    Drug delivery through hollow microneedle (HMN) arrays has now been recognized as one of the most promising techniques because it minimizes the shortcomings of the traditional drug delivery methods and has many exciting advantages—pain free and tunable release rates, for example. However, this drug delivery method has been hindered greatly from mass clinical application because of the high fabrication cost of HMN arrays. Hence, we developed a simple and cost-effective procedure using silica needles as templates to massively fabricate HMN arrays by using popular materials and industrially applicable processes of micro- imprint, hot embossing, electroplating and polishing. Metal HMN arrays with high quality are prepared with great flexibility with tunable parameters of area, length of needle, size of hollow and array dimension. This efficient and cost-effective fabrication method can also be applied to other applications after minor alterations, such as preparation of optic, acoustic and solar harvesting materials and devices.

  12. Needles of Pinus halepensis as biomonitors of bioaerosol emissions.

    Directory of Open Access Journals (Sweden)

    Amandine Galès

    Full Text Available We propose using the surface of pine trees needles to biomonitor the bioaerosol emissions at a composting plant. Measurements were based on 16S rRNA gene copy numbers of Saccharopolyspora rectivirgula, a bioindicator of composting plant emissions. A sampling plan was established based on 29 samples around the emission source. The abundance of 16S rRNA gene copies of S. rectivirgula per gram of Pinus halepensis needles varied from 104 to 102 as a function of the distance. The signal reached the background level at distances around the composting plant ranging from 2 km to more than 5.4 km, depending on the local topography and average wind directions. From these values, the impacted area around the source of bioaerosols was mapped.

  13. Ocular Needling for Treatment of Sudden Deafness in 40 Cases

    Institute of Scientific and Technical Information of China (English)

    石晶; 郑振

    2004-01-01

    @@ Sudden deafness is a commonly encountered otological disease. The etiology and pathogenesis are still unknown, and therefore no ideal treatment is available. In clinical, the disease is treated to recover the cellular functions by improving the microcirculation of the inner ear and nourishing the nerves. To seek a more effective method, we conducted a trial with ocular needling in 40 patients from May 1998 to April 2000. The therapeutic results were satisfactory as reported in the following.

  14. Treatment of Postherpetic Neuralgia by Surround Needling with Electric Stimulation

    Institute of Scientific and Technical Information of China (English)

    FAN Jin; YANG Qin-hua

    2005-01-01

    运用电针围刺法治疗带状疱疹后遗神经痛29例,获得较好疗效,总有效率为93.1%.%Twenty-nine cases of postherpetic neuralgia of herpes zoster were treated by the surround needling with electric stimulation, and the better therapeutic effect was obtained, the total effective rate was 93.1%.

  15. Fine-needle aspiration cytology in Hodgkin’s lymphoma

    Directory of Open Access Journals (Sweden)

    Nedeljkov-Jančić Ružica

    2005-01-01

    Full Text Available Background. Cell composition of tumor tissue in Hodgkin’s lymphoma is considered to be specific. According to some authors, precise cytomorphological analysis of the specimen obtained by fine needle enables the diagnosis of the histologically well-defined form of lymphoma in a high percentage of cases. However, other authors consider the precise diagnosis of HL based on cytological analysis of a lymph node puncture specimen extremely difficult. The aim of this study was to a assess the diagnostic accuracy of cytomorphological analysis, as well as the possibility of application of this method in establishing the preliminary or even final diagnosis of this form of lymphoma. Methods. Thirty four samples were analyzed, obtained by fine needle aspiration, in patients examined and treated at the Institute of Hematology, Clinical center of Serbia, Belgrade. Smears were stained by May-Grünvald-Giemsa and Papanicolau methods. Results. The finding of typical multinucleate Reed-Sternberg cells in the smears of lymph node puncture specimen was diagnostically significant, as well as the finding of mononuclear variances of the neoplastic cells of anunusual morphology (Hodgkin’s cells. The cell environment in the background of the above-mentioned tumor cells was heterogeneous. It was composed of small lymphocytes, plasma cells, eosinophils and reticular cells. These cell forms, found in cell preparations, resembled those seen in the tissue sections of the relevant extirpated lymph nodes. The comparison of the cytological findings in the fine needle specimen to the subsequently established histological diagnoses of HL revealed a high correlation of 85.2%. Conclusion. Cytological examination of fine needle lymph node specimens is still significant for the diagnosis of HL in spite of the development of more sophisticated methods used for verification of the diagnosis of this neoplasm.

  16. Treatment of 120 Cases of Acne by Scattered Needling Therapy

    Institute of Scientific and Technical Information of China (English)

    WEI Bo; JIANG Hong-cheng; ZHU Zhong-chun

    2004-01-01

    @@ We have treated 120 cases of acne with scattered needling therapy at affected part. Clinical Data All the 120 patients, coming from the training center of acupuncture and moxibustion, department of TCM of medical college, Ji'nan University, were students of Ji'nan university, 22 cases were male, 98 cases were female; The youngest was 19 years and the oldest 23years; The shortest duration of disease was 1 year and the longest 7 years.

  17. Fine Needle Aspiration Cytology of Pediatric Thyroid Nodules

    Directory of Open Access Journals (Sweden)

    Ayper KAÇAR

    2010-05-01

    Full Text Available Objective: The objectives were to evaluate fine needle aspiration cytology results of 39 pediatric patients, and the pathologies that cause childhood thyroid nodules, and to review the literature on the subject.Material and Method: Thyroid fine needle aspiration cytology results of 39 pediatric patients were retrospectively reviewed. Associated diseases, thyroid functions, anti-thyroid antibody levels, ultrasonographic findings and number of nodules were also evaluated.Results: The vast majority of patients with thyroid nodules were cytopathologically diagnosed as benign (97.3%. Of these patients, 64.8% (24 patients were diagnosed as nodular goiter and 35.2% (13 patients as lymphocytic thyroiditis. Thyroid malignancy was found in two patients; one was diagnosed as follicular neoplasm/ minimal invasive follicular carcinoma on surgical evaluation while the other was a secondary tumor (Burkitt's lymphoma. The majority of our subjects were females (66.6%: the female/male ratio was 2:1 for nodular goiter and 3.3:1 for thyroiditis. Surgical resection was performed in 5 patients (4 cases of nodular goiter, 1 suspicious for malignancy and cytological diagnoses were confirmed by histology.Conclusion: Our study confirmed the utility of fine needle aspiration cytology in childhood thyroid disorders along with a possible higher incidence of nodular thyroiditis in childhood. Nodular autoimmune thyroiditis, focal thyroiditis and thyroid cancer in children are discussed and attention is drawn to some special subtypes of thyroid cancer and some benign lesions that can cause difficulty in interpreting fine needle aspiration cytology and frozen sections at this age.

  18. Needle placement for piriformis injection using 3-D imaging.

    Science.gov (United States)

    Clendenen, Steven R; Candler, Shawn A; Osborne, Michael D; Palmer, Scott C; Duench, Stephanie; Glynn, Laura; Ghazi, Salim M

    2013-01-01

    Piriformis syndrome is a pain syndrome originating in the buttock and is attributed to 6% - 8% of patients referred for the treatment of back and leg pain. The treatment for piriformis syndrome using fluoroscopy, computed tomography (CT), electromyography (EMG), and ultrasound (US) has become standard practice. The treatment of Piriformis Syndrome has evolved to include fluoroscopy and EMG with CT guidance. We present a case study of 5 successful piriformis injections using 3-D computer-assisted electromagnet needle tracking coupled with ultrasound. A 6-degree of freedom electromagnetic position tracker was attached to the ultrasound probe that allowed the system to detect the position and orientation of the probe in the magnetic field. The tracked ultrasound probe was used to find the posterior superior iliac spine. Subsequently, 3 points were captured to register the ultrasound image with the CT or magnetic resonance image scan. Moreover, after the registration was obtained, the navigation system visualized the tracked needle relative to the CT scan in real-time using 2 orthogonal multi-planar reconstructions centered at the tracked needle tip. Conversely, a recent study revealed that fluoroscopically guided injections had 30% accuracy compared to ultrasound guided injections, which tripled the accuracy percentage. This novel technique exhibited an accurate needle guidance injection precision of 98% while advancing to the piriformis muscle and avoiding the sciatic nerve. The mean (± SD) procedure time was 19.08 (± 4.9) minutes. This technique allows for electromagnetic instrument tip tracking with real-time 3-D guidance to the selected target. As with any new technique, a learning curve is expected; however, this technique could offer an alternative, minimizing radiation exposure.

  19. Riedel thyroiditis: Fine needle aspiration findings of a rare entity.

    Science.gov (United States)

    Weidner, Anna-Sophie; Molina, David; DeSimone, Robert A; Cohen, Marc A; Giorgadze, Tamar; Scognamiglio, Theresa; Hoda, Rana S

    2015-09-01

    Riedel thyroiditis is a rare fibrosing disorder characterized by extension of the fibroinflammatory process beyond the thyroid capsule. Due to the nature of this lesion, fine-needle aspiration often yields scant material and may be interpreted as non-diagnostic. In this report, we describe cytologic features that allow the cytopathologist to favor a diagnosis of Riedel thyroiditis, thereby guiding appropriate further work-up and management.

  20. NEEDLE REVISION WITH MITOMYCIN-C IN ENCAPSULATED BLEBS

    Directory of Open Access Journals (Sweden)

    R Zarei

    2008-08-01

    Full Text Available "nThe most common cause of failure during the first trimester after trabeculectomy is encapsulated bleb and needling bleb revision is a less invasive method in the management of refractory cases. The purpose of this study is to determine the efficacy and safety of mitomycin-C (MMC augmented bleb revision of failed filtration surgery. This study is a before-after (paired observation. 33 patients with failed trabeculectomy because of bleb encapsulation, whose intraocular pressure (IOP was not reduced under 21 mmHg despite of medications and digital massage , underwent needling bleb revision and subconjunctival injection of 0.1 ml MMC (0.4 mg/ml.The mean follow-up time was 9.24 ± 5.27 months (1-20 months. Statistical analysis of the data included the paired two-tailed Student's t test for preoperative and postoperative IOP and number of medications. 36 needling procedures (mean, 1.09 ± 0.21 revisions per eye were performed on 33 eyes. Patients were between 10-80 years old (mean, 45.67 ± 22.41 years and mean follow-up was 9.24 ± 5.27 months. IOP decreased from 29.06 ± 5.03 mmHg to 18.21 ± 6.76 mmHg at last follow-up (P= 0.000. Antiglaucoma medications decreased from 2.18 ± 0.58 to 1.36 ± 0.29 at last follow-up (P= 0.000.Overall, 6 (18.2% of 33 cases achieved a complete success and 20 (60.6% of cases achieved a qualified success. The complications of this procedure were subconjunctival hemorrhage (17 cases, hyphema (5 cases and conjunctival button hole (2 cases. Needling bleb revision with mitomycin-C appears to be an effective and relatively safe way to revive failed filtration surgery.

  1. Deactivation of Escherichia coli by the plasma needle

    Energy Technology Data Exchange (ETDEWEB)

    Sladek, R E J; Stoffels, E [Department of Biomedical Engineering, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven (Netherlands)

    2005-06-07

    In this paper we present a parameter study on deactivation of Escherichia coli (E. coli) by means of a non-thermal plasma (plasma needle). The plasma needle is a small-sized (1 mm) atmospheric glow sustained by radio-frequency excitation. This plasma will be used to disinfect heat-sensitive objects; one of the intended applications is in vivo deactivation of dental bacteria: destruction of plaque and treatment of caries. We use E. coli films plated on agar dishes as a model system to optimize the conditions for bacterial destruction. Plasma power, treatment time and needle-to-sample distance are varied. Plasma treatment of E. coli films results in formation of a bacteria-free void with a size up to 12 mm. 10{sup 4}-10{sup 5} colony forming units are already destroyed after 10 s of treatment. Prolongation of treatment time and usage of high powers do not significantly improve the destruction efficiency: short exposure at low plasma power is sufficient. Furthermore, we study the effects of temperature increase on the survival of E. coli and compare it with thermal effects of the plasma. The population of E. coli heated in a warm water bath starts to decrease at temperatures above 40 deg. C. Sample temperature during plasma treatment has been monitored. The temperature can reach up to 60 deg. C at high plasma powers and short needle-to-sample distances. However, thermal effects cannot account for bacterial destruction at low power conditions. For safe and efficient in vivo disinfection, the sample temperature should be kept low. Thus, plasma power and treatment time should not exceed 150 mW and 60 s, respectively.

  2. Development and modeling of novel extensional ionic polymer transducers

    Science.gov (United States)

    Akle, Barbar; Wallmersperger, Thomas; Leo, Donald

    2007-04-01

    Ionic polymer transducers (IPT), sometimes referred to as artificial muscles, are known to generate a large bending strain and a moderate stress at low applied voltages. Bending actuators have limited engineering applications due to the low forcing capabilities and the need for complicated external devices to convert the bending action into rotating or linear motion desired in most devices. Recently Akle and Leo (2006) reported extensional actuation in ionic polymer transducers. Model prediction indicates that such actuators can produce strain up to 10% and a blocked stress up to 20MPa under a +/- 2V applied electric potential. Compared to other smart materials, IPT is a flexible membrane and it has a reliability of over one million cycles. In this work novel extensional IPT actuators are developed for the purpose of increasing the overall displacement of the actuator. The electromechanical coupling is measured and a correlation of the experimental data with the active areas model by Akle and Leo (2006) and the numerical electromechanical model by Wallmersperger and Leo (2004) are presented. The coupling between each test case with the model parameters enables further understanding of the physical actuation phenomena as the role of diffusion of ions and diluents and the electrostatic forces between the charged species. In this study the displacement of an extensional ionic polymer transducer is measured and compared to the bending of the same IPT actuator. The bending strain is measured to be approximately 2.5%, while the extensional strain for the same ionomer is in the order of 17.5%. Finally an interesting behavior, reported for the first time is the steady expansion of the IPT sample due to the application of a symmetrical sine wave. This indicates that charge accumulation is occurring at the electrode.

  3. Advanced piezoelectric single crystal based transducers for naval sonar applications

    Science.gov (United States)

    Snook, Kevin A.; Rehrig, Paul W.; Hackenberger, Wesley S.; Jiang, Xiaoning; Meyer, Richard J., Jr.; Markley, Douglas

    2006-03-01

    Transducers incorporating single crystal piezoelectric Pb(Mg 1/3Nb 2/3) x-1Ti xO 3 (PMN-PT) exhibit significant advantages over ceramic piezoelectrics such as PZT, including both high electromechanical coupling (k 33 > 90%) and piezoelectric coefficients (d 33 > 2000 pC/N). Conventional orientation gives inherently larger bandwidth and output power than PZT ceramics, however, the anisotropy of the crystal also allows for tailoring of the performance by orienting the crystal along different crystallographic axes. This attribute combined with composition refinements can be used to improve thermal or mechanical stability, which is important in high power, high duty cycle sonar applications. By utilizing the "31" resonance mode, the high power performance of PMN-PT can be improved over traditional "33" mode single crystal transducers, due to an improved aspect ratio. Utilizing novel geometries, effective piezoelectric constants of -600 pC/N to -1200 pC/N have been measured. The phase transition point induced by temperature, pre-stress or field is close to that in the "33" mode, and since the prestress is applied perpendicular to the poling direction in "31" mode elements, they exhibit lower loss and can therefore be driven harder. The high power characteristics of tonpilz transducers can also be affected by the composition of the PMN-PT crystal. TRS modified the composition of PMN-PT to improve the thermal stability of the material, while keeping the loss as low as possible. Three dimensional modeling shows that the useable bandwidth of these novel compositions nearly equals that of conventional PMN-PT. A decrease in the source level of up to 6 dB was calculated, which can be compensated for by the higher drive voltages possible.

  4. Vibration control via stiffness switching of magnetostrictive transducers

    Science.gov (United States)

    Scheidler, Justin J.; Asnani, Vivake M.; Dapino, Marcelo J.

    2016-04-01

    In this paper, a computational study is presented of structural vibration control that is realized by switching a magneto-strictive transducer between high and low stiffness states. Switching is accomplished by either changing the applied magnetic field with a voltage excitation or changing the shunt impedance on the transducer's coil (i.e., the magneto-strictive material's magnetic boundary condition). Switched-stiffness vibration control is simulated using a lumped mass supported by a damper and the magneto-strictive transducer (mount), which is represented by a nonlinear, electromechanical model. Free vibration of the mass is calculated while varying the mount's stiffness according to a reference switched-stiffness vibration control law. The results reveal that switching the magnetic field produces the desired change in stiffness, but also an undesired actuation force that can significantly degrade the vibration control. Hence, a modified switched-stiffness control law that accounts for the actuation force is proposed and implemented for voltage-controlled stiffness switching. The influence of the magneto-mechanical bias condition is also discussed. Voltage-controlled stiffness switching is found to introduce damping equivalent to a viscous damping factor up to about 0.13; this is shown to primarily result from active vibration reduction caused by the actuation force. The merit of magneto-strictive switched-stiffness vibration control is then quantified by comparing the results of voltage- and shunt-controlled stiffness switching to the performance of optimal magneto-strictive shunt damping. For the cases considered, optimal resistive shunt damping performed considerably better than both voltage- and shunt-controlled stiffness switching.

  5. Interrater reliability of the needle examination in lumbosacral radiculopathy.

    Science.gov (United States)

    Kendall, Richard; Werner, Robert A

    2006-08-01

    Low back pain and lumbar radiculopathy are among the most common painful disorders affecting the adult population. This study hypothesizes that there is good correlation between the diagnostic impression of an unblinded electromyographer, using clinical and electromyographic information, and an independent electromyographer, who uses the needle examination only to assess for lumbar radiculopathy. This is a prospective, single-blinded, observational pilot study. The needle examination was electronically recorded, reproduced, and shown to a second examiner, blinded to all clinical data. Diagnostic impressions from both examiners were recorded and evaluated for agreement. Six recorded cases were reviewed by 66 blinded examiners. Overall diagnostic agreement was 46.9% (60.5% faculty level, 28.5% resident level). Logistic regression shows a strong association between training level and agreement on diagnostic impression (odds ratio, 1.9; 95% confidence interval, 1.12-3.22; P = 0.019). This study shows that there is fair interrater reliability between faculty-level examiners and poor reliability among resident-level examiners when the needle examination is used to evaluate patients with lumbar radiculopathy.

  6. PERIPHERAL FACIAL PARALYSIS TREATED BY MULTI-DIRECTIONAL NEEDLING

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    Objective: To search for an effective therapy in treating peripheral facial paralysis. Methods:One hundred and eight patients were randomly divided into treatment group (n =68) and control group (n =40). The multi-directional needling technique was used by selecting Jiache (颊车 ST 6), Yangbai (阳白 GB14) and Dicang (地仓 ST 4) in the treatment group, and the traditional acupuncture technique with conventional needle selection was used in the control group. The treatment was given once daily with 10 treatments constituting a therapeutic course, and 2 courses of treatment were given in both the groups. Results: After the treatment, of the 68 and 40 cases in treatment and control groups, 56 (82.3%) and 28 (70.0%) were cured, 11 (16.2%) and 8 (20.0%) improved in clinical symptoms and signs, 1 (1.5%) and 4 (10.0%) failed, with the total effective rate being 98.5% and 90.0% respectively, and the therapeutic effect of treatment group was significantly superior to that of control group ( P< 0.05). Conclusion: The multi-directional needling is an effective therapy for treating peripheral facial paralysis.

  7. Efficacy of dry needling for treatment of myofascial pain syndrome.

    Science.gov (United States)

    Fogelman, Yacov; Kent, John

    2015-01-01

    Myofascial pain is a major cause of musculoskeletal regional pain. Myofascial pain, which is a high-prevalence but eminently treatable condition, is almost universally underdiagnosed by physicians and undertreated by physical therapy modalities. Large numbers of patients can be left suffering in chronic pain for years. Dry needling, also referred to as Intramuscular Stimulation, is a method in the arsenal of pain management which has been known for almost 200 years in Western medicine, yet has been almost completely ignored. With the increase in research in this field over the past two decades, there are many high-quality studies that demonstrate dry needling to be an effective and safe method for the treatment of myofascial pain when diagnosed and treated by adequately-trained physicians or physical therapists. This article provides an overview of recent literature regarding the treatment of myofascial pain syndrome, evidence for the efficacy of dry needling as a central component of its management, and a glimpse at developments in recent imaging methods to aid in the treatment of these problems.

  8. Probable Mechanisms of Needling Therapies for Myofascial Pain Control

    Directory of Open Access Journals (Sweden)

    Li-Wei Chou

    2012-01-01

    Full Text Available Myofascial pain syndrome (MPS has been defined as a regional pain syndrome characterized by muscle pain caused by myofascial trigger points (MTrPs clinically. MTrP is defined as the hyperirritable spot in a palpable taut band of skeletal muscle fibers. Appropriate treatment to MTrPs can effectively relieve the clinical pain of MPS. Needling therapies, such as MTrP injection, dry needling, or acupuncture (AcP can effectively eliminate pain immediately. AcP is probably the first reported technique in treating MPS patients with dry needling based on the Traditional Chinese Medicine (TCM theory. The possible mechanism of AcP analgesia were studied and published in recent decades. The analgesic effect of AcP is hypothesized to be related to immune, hormonal, and nervous systems. Compared to slow-acting hormonal system, nervous system acts in a faster manner. Given these complexities, AcP analgesia cannot be explained by any single mechanism. There are several principles for selection of acupoints based on the TCM principles: “Ah-Shi” point, proximal or remote acupoints on the meridian, and extra-meridian acupoints. Correlations between acupoints and MTrPs are discussed. Some clinical and animal studies of remote AcP for MTrPs and the possible mechanisms of remote effectiveness are reviewed and discussed.

  9. Comparison of Methods for Protein Extraction from Pine Needles

    Institute of Scientific and Technical Information of China (English)

    2005-01-01

    Extraction of proteins from pine needles for proteomic analysis has long been a challenge for scientists. We compared three different protein extraction methods including sucrose, Tris-HCl and trichloroacetic acid (TCA)/acetone (TCA method) to determine their efficiency in separating pine needle proteins by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and two-dimensional PAGE (2D-PAGE). Proteins were then separated by SDS-PAGE. Among three methods the method using sucrose extraction buffer showed the highest efficiency and highest quality in separating proteins. In addition, clearer and more stable strips were detected by SDS-PAGE using sucrose extraction buffer. When the proteins extracted using sucrose extraction buffer were separated by 2D-PAGE, more than 300 protein spots, with isoelectric points (PI) ranging from 4.0 to 7.0 and molecular weights (MW) from 6.5 to 97.4 kD, were observed. This confirmed that the method with sucrose extraction buffer was an efficient and reliable method for extracting proteins from pine needles.

  10. Capacitive micromachined ultrasonic transducer arrays as tunable acoustic metamaterials

    Energy Technology Data Exchange (ETDEWEB)

    Lani, Shane W., E-mail: shane.w.lani@gmail.com, E-mail: karim.sabra@me.gatech.edu, E-mail: levent.degertekin@me.gatech.edu; Sabra, Karim G. [George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 801Ferst Drive, Georgia 30332-0405 (United States); Wasequr Rashid, M.; Hasler, Jennifer [School of Electrical and Computer Engineering, Georgia Institute of Technology, Van Leer Electrical Engineering Building, 777 Atlantic Drive NW, Atlanta, Georgia 30332-0250 (United States); Levent Degertekin, F. [George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, 801Ferst Drive, Georgia 30332-0405 (United States); School of Electrical and Computer Engineering, Georgia Institute of Technology, Van Leer Electrical Engineering Building, 777 Atlantic Drive NW, Atlanta, Georgia 30332-0250 (United States)

    2014-02-03

    Capacitive Micromachined Ultrasonic Transducers (CMUTs) operating in immersion support dispersive evanescent waves due to the subwavelength periodic structure of electrostatically actuated membranes in the array. Evanescent wave characteristics also depend on the membrane resonance which is modified by the externally applied bias voltage, offering a mechanism to tune the CMUT array as an acoustic metamaterial. The dispersion and tunability characteristics are examined using a computationally efficient, mutual radiation impedance based approach to model a finite-size array and realistic parameters of variation. The simulations are verified, and tunability is demonstrated by experiments on a linear CMUT array operating in 2-12 MHz range.

  11. Fluids as transducers of gravity in biological systems

    CERN Document Server

    Lofthouse, J

    2004-01-01

    A qualitative model is presented, suggesting gravitational information is transduced into biological systems primarily by its effect on spatially organised membrane and cytoplasmic flows. Continuous low affinity interactions between membrane bound cytoskeletal proteins and phospholipid flows that are undergoing forced convective and shear driven flows are shown to convert this information into spatial protein patterns, and hence cell shape. As applied here to plant cells, the feedback mechanism is shown capable not only of establishing the strict nanometer scale parallelism that exists between proteins running on the inside and outside of the cell membrane, but also to predict its maintainance and the angle of fibre realignment observed during tropic responses.

  12. Simulating arbitrary-geometry ultrasound transducers using triangles

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt

    1996-01-01

    -echo field. The spatial impulse response has only been determined analytically for a few geometries and using apodization over the transducer surface generally makes it impossible to find the response analytically. A popular approach to find the general field is thus to split the aperture into small...... focused at different zones. The time-integrated spatial impulse response is used in the program to minimize the effect of the sharp edges of the spatial impulse response in a sampled signal. Since the integrated response from a triangular element cannot be analytically evaluated, a simple numerical...

  13. Laser-scanning photoacoustic microscopy with ultrasonic phased array transducer

    OpenAIRE

    Zheng, Fan; Zhang, Xiangyang; Chiu, Chi Tat; Zhou, Bill L.; Shung, K. Kirk; Zhang, Hao F.; Jiao, Shuliang

    2012-01-01

    In this paper, we report our latest progress on proving the concept that ultrasonic phased array can improve the detection sensitivity and field of view (FOV) in laser-scanning photoacoustic microscopy (LS-PAM). A LS-PAM system with a one-dimensional (1D) ultrasonic phased array was built for the experiments. The 1D phased array transducer consists of 64 active elements with an overall active dimension of 3.2 mm × 2 mm. The system was tested on imaging phantom and mouse ear in vivo. Experimen...

  14. Speech recognition algorithms based on weighted finite-state transducers

    CERN Document Server

    Hori, Takaaki

    2013-01-01

    This book introduces the theory, algorithms, and implementation techniques for efficient decoding in speech recognition mainly focusing on the Weighted Finite-State Transducer (WFST) approach. The decoding process for speech recognition is viewed as a search problem whose goal is to find a sequence of words that best matches an input speech signal. Since this process becomes computationally more expensive as the system vocabulary size increases, research has long been devoted to reducing the computational cost. Recently, the WFST approach has become an important state-of-the-art speech recogni

  15. Quantum acousto-optic transducer for superconducting qubits

    CERN Document Server

    Shumeiko, V S

    2015-01-01

    We propose theory for reversible quantum transducer connecting superconducting qubits and optical photons using acoustic waves in piezoelectrics. The proposed device consists of integrated acousto-optic resonator that utilizes stimulated Brillouin scattering for phonon-photon conversion, and piezoelectric e?ect for coupling of phonons to qubits. We evaluate the phonon-photon coupling rate, and show that the required power of optical pump as well as the other device parameters providing full and faithful quantum conversion are feasible for implementation with the state of the art integrated acousto-optics.

  16. Experimental Analysis of Bisbenzocyclobutene Bonded Capacitive Micromachined Ultrasonic Transducers

    OpenAIRE

    2016-01-01

    Experimental measurement results of a 1.75 mm × 1.75 mm footprint area Capacitive Micromachined Ultrasonic Transducer (CMUT) planar array fabricated using a bisbenzocyclobutene (BCB)-based adhesive wafer bonding technique has been presented. The array consists of 40 × 40 square diaphragm CMUT cells with a cavity thickness of 900 nm and supported by 10 µm wide dielectric spacers patterned on a thin layer of BCB. A 150 µm wide one µm thick gold strip has been used as the contact pad for gold wi...

  17. Minimizing RF Performance Spikes in a Cryogenic Orthomode Transducer (OMT)

    Science.gov (United States)

    Henke, Doug; Claude, Stephane

    2014-04-01

    The turnstile junction exhibits very low cross-polarization leakage and is suitable for low-noise millimeter-wave receivers. For use in a cryogenic receiver, it is best if the orthomode transducer (OMT) is implemented in waveguide, contains no additional assembly features, and may be directly machined. However, machined OMTs are prone to sharp signal drop-outs that are costly to overall performance since they show up directly as spikes in receiver noise. We explore the various factors contributing to this degradation and discuss how the current design mitigates each cause. Final performance is demonstrated at cryogenic temperatures.

  18. Patients’ Knowledge of and Practices Relating to the Disposal of Used Insulin Needles

    Directory of Open Access Journals (Sweden)

    Kerri T. Musselman, PharmD

    2010-01-01

    Full Text Available Objective: To determine (1 how patients currently dispose of used insulin needles, (2 whether patients were educated about disposal of their used insulin needles, and (3 who educated patients about the disposal of their used insulin needles.Methods: A self-administered questionnaire was designed for this study. The survey assessed patient knowledge about disposal of used insulin needles and the patient-reported source and location of education about disposal techniques. The questionnaire was administered to a convenience sample of patients from four locations in Richmond, Virginia. Any patient who used insulin, was at least 18 years old, and was willing to complete the survey was eligible for inclusion.Results: Fifty responses were received with 40% indicating that education had been received on the disposal of used needles. From that 40%, nurses were identified as the source of education 60% of the time and pharmacists 25% of the time. Approximately 50% of the respondents reported disposing of used needles directly in the trash when at home. While away from home, 22% reported placing used needles in the trash, and 38% took them home for disposal.Conclusion: Patients are not consistently educated regarding the proper disposal of used needles. Health care practitioners should play a larger role in educating patients about the potential risks of inappropriate needle disposal and appropriate disposal methods. Future research is still needed to understand fully the magnitude of the problems associated with inappropriate needle disposal by patients.

  19. Optimal needle arrangement for intraoperative planning in permanent I-125 prostate implants

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, S.A. [Department of Medical Physics, North Shore-Long Island Jewish Health System, Manhassett, NY (United States); Fung, A.Y.C.; Zaider, M. [Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY (United States)

    2002-08-21

    One limitation of intraoperative planning of permanent prostate implants is that needles must already be in the gland before planning images are acquired. Improperly placed needles often restrict the capability of generating optimal seed placement. We developed guiding principles for the proper layout of needles within the treatment volume. The Memorial Sloan-Kettering Cancer Center planning system employs a genetic algorithm to find the optimal seed implantation pattern consistent with pre-assigned constraints (needle geometry, uniformity, conformity and the avoidance of high doses to urethra and rectum). Ultrasound volumes for twelve patients with I-125 implants were used to generate six plans per patient (total 72 plans) with different needle arrangements. The plans were evaluated in terms of V100 (percentage prostate volume receiving at least the prescription dose), U135 (percentage urethra volume receiving at least 135% of prescription dose), and CI (conformity index, the ratio of treatment volume to prescription dose volume.) The method termed POSTCTR, in which needles were placed on the periphery of the largest ultrasound slice and posterior central needles were placed as needed, consistently gave superior results for all prostate sizes. Another arrangement, labelled POSTLAT, where the needles were placed peripherally with additional needles in the posterior lateral lobes, also gave satisfactory results. We advocate two needle arrangements, POSTCTR and POSTLAT, with the former giving better results. (author)

  20. NOTE: Optimal needle arrangement for intraoperative planning in permanent I-125 prostate implants

    Science.gov (United States)

    Thompson, S. A.; Fung, A. Y. C.; Zaider, M.

    2002-08-01

    One limitation of intraoperative planning of permanent prostate implants is that needles must already be in the gland before planning images are acquired. Improperly placed needles often restrict the capability of generating optimal seed placement. We developed guiding principles for the proper layout of needles within the treatment volume. The Memorial Sloan-Kettering Cancer Center planning system employs a genetic algorithm to find the optimal seed implantation pattern consistent with pre-assigned constraints (needle geometry, uniformity, conformity and the avoidance of high doses to urethra and rectum). Ultrasound volumes for twelve patients with I-125 implants were used to generate six plans per patient (total 72 plans) with different needle arrangements. The plans were evaluated in terms of V100 (percentage prostate volume receiving at least the prescription dose), U135 (percentage urethra volume receiving at least 135% of prescription dose), and CI (conformity index, the ratio of treatment volume to prescription dose volume.) The method termed POSTCTR, in which needles were placed on the periphery of the largest ultrasound slice and posterior central needles were placed as needed, consistently gave superior results for all prostate sizes. Another arrangement, labelled POSTLAT, where the needles were placed peripherally with additional needles in the posterior lateral lobes, also gave satisfactory results. We advocate two needle arrangements, POSTCTR and POSTLAT, with the former giving better results.