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Sample records for dual element transducers

  1. Nanomaterial-based biosensors using dual transducing elements for solution phase detection.

    Science.gov (United States)

    Li, Ning; Su, Xiaodi; Lu, Yi

    2015-05-07

    Biosensors incorporating nanomaterials have demonstrated superior performance compared to their conventional counterparts. Most reported sensors use nanomaterials as a single transducer of signals, while biosensor designs using dual transducing elements have emerged as new approaches to further improve overall sensing performance. This review focuses on recent developments in nanomaterial-based biosensors using dual transducing elements for solution phase detection. The review begins with a brief introduction of the commonly used nanomaterial transducers suitable for designing dual element sensors, including quantum dots, metal nanoparticles, upconversion nanoparticles, graphene, graphene oxide, carbon nanotubes, and carbon nanodots. This is followed by the presentation of the four basic design principles, namely Förster Resonance Energy Transfer (FRET), Amplified Fluorescence Polarization (AFP), Bio-barcode Assay (BCA) and Chemiluminescence (CL), involving either two kinds of nanomaterials, or one nanomaterial and an organic luminescent agent (e.g. organic dyes, luminescent polymers) as dual transducers. Biomolecular and chemical analytes or biological interactions are detected by their control of the assembly and disassembly of the two transducing elements that change the distance between them, the size of the fluorophore-containing composite, or the catalytic properties of the nanomaterial transducers, among other property changes. Comparative discussions on their respective design rules and overall performances are presented afterwards. Compared with the single transducer biosensor design, such a dual-transducer configuration exhibits much enhanced flexibility and design versatility, allowing biosensors to be more specifically devised for various purposes. The review ends by highlighting some of the further development opportunities in this field.

  2. Acoustic characterization of multi-element, dual-frequency transducers for high-intensity contact ultrasound therapy

    Science.gov (United States)

    Burtnyk, M.; N'Djin, W. A.; Persaud, L.; Bronskill, M.; Chopra, R.

    2012-10-01

    High-intensity contact ultrasound therapy can generate precise volumes of thermal damage in deep-seated tissue using interstitial or intracavitary devices. Multi-element, dual-frequency transducers offer increased spatial control of the heating pattern by enabling modulation of ultrasound power and frequency along the device. The performance and acoustic coupling between elements of simple, multi-element, dual-frequency transducers was measured. Transducer arrays were fabricated by cutting halfway through a rectangular plate of PZT, creating individual 4 × 5 mm segments with fundamental frequency (4.1 MHz) and third harmonic (13.3 MHz). Coupling between elements was investigated using a scanning laser vibrometer to measure transducer surface displacements at each frequency and different acoustic powers (0, 10, 20 W/cm2). The measured acoustic power was proportional to the input electrical power with no hysteresis and efficiencies >50% at both frequencies. Maximum transducer surface displacements were observed near element centers, reducing to ˜1/3-maximum near edges. The power and frequency of neighboring transducer segments had little impact on an element's output. In the worst case, an element operating at 4.1 MHz and 20 W/cm2 coupled only 1.5 W/cm2 to its immediate neighboring element. Multi-element, dual-frequency transducers were successfully constructed using a simple dicing method. Coupling between elements was minor, therefore the power and frequency of each transducer element could be considered independent.

  3. Dual-Element Transducer with Phase-Inversion for Wide Depth of Field in High-Frequency Ultrasound Imaging

    Directory of Open Access Journals (Sweden)

    Jong Seob Jeong

    2014-08-01

    Full Text Available In high frequency ultrasound imaging (HFUI, the quality of focusing is deeply related to the length of the depth of field (DOF. In this paper, a phase-inversion technique implemented by a dual-element transducer is proposed to enlarge the DOF. The performance of the proposed method was numerically demonstrated by using the ultrasound simulation program called Field-II. A simulated dual-element transducer was composed of a disc- and an annular-type elements, and its aperture was concavely shaped to have a confocal point at 6 mm. The area of each element was identical in order to provide same intensity at the focal point. The outer diameters of the inner and the outer elements were 2.1 mm and 3 mm, respectively. The center frequency of each element was 40 MHz and the f-number (focal depth/aperture size was two. When two input signals with 0° and 180° phases were applied to inner and outer elements simultaneously, a multi-focal zone was generated in the axial direction. The total −6 dB DOF, i.e., sum of two −6 dB DOFs in the near and far field lobes, was 40% longer than that of the conventional single element transducer. The signal to noise ratio (SNR was increased by about two times, especially in the far field. The point and cyst phantom simulation were conducted and their results were identical to that of the beam pattern simulation. Thus, the proposed scheme may be a potential method to improve the DOF and SNR in HFUI.

  4. A dual-piston ring-driven X-spring transducer

    Science.gov (United States)

    Butler, Alexander L.; Butler, John L.; Pendleton, Robert L.; Ead, Richard M.

    2004-05-01

    Tonpilz transducers generally consist of a stack of piezoelectric material sandwiched between a single piston and an inertial tail mass or between two pistons. The result is a transducer with a large length-to-diameter ratio. The X-spring transducer design, based on U.S. Patent 4845688, allows a means for a shorter transducer length through an orthogonal piezoelectric drive system coupled to the pistons by lever arms. We present here a low-frequency, dual-piston piezoelectric ceramic ring driven version with a length of only 10 in. and a diameter of 19 in. Both single-element and two-element array results are presented. The measured response is shown to be in agreement with the finite-element model with a smooth, wideband 300- to 550-Hz response for this dual-piston, ring-driven X-spring transducer. [Work supported by a Phase II SBIR, through NUWC, Newport, RI 02841.

  5. Dual-frequency transducer for nonlinear contrast agent imaging.

    Science.gov (United States)

    Guiroy, Axel; Novell, Anthony; Ringgaard, Erling; Lou-Moeller, Rasmus; Grégoire, Jean-Marc; Abellard, André-Pierre; Zawada, Tomasz; Bouakaz, Ayache; Levassort, Franck

    2013-12-01

    Detection of high-order nonlinear components issued from microbubbles has emerged as a sensitive method for contrast agent imaging. Nevertheless, the detection of these high-frequency components, including the third, fourth, and fifth harmonics, remains challenging because of the lack of transducer sensitivity and bandwidth. In this context, we propose a new design of imaging transducer based on a simple fabrication process for high-frequency nonlinear imaging. The transducer is composed of two elements: the outer low-frequency (LF) element was centered at 4 MHz and used in transmit mode, whereas the inner high-frequency (HF) element centered at 14 MHz was used in receive mode. The center element was pad-printed using a lead zirconate titanate (PZT) paste. The outer element was molded using a commercial PZT, and curved porous unpoled PZT was used as backing. Each piezoelectric element was characterized to determine the electromechanical performance with thickness coupling factor around 45%. After the assembly of the two transducer elements, hydrophone measurements (electroacoustic responses and radiation patterns) were carried out and demonstrated a large bandwidth (70% at -3 dB) of the HF transducer. Finally, the transducer was evaluated for contrast agent imaging using contrast agent microbubbles. The results showed that harmonic components (up to the sixth harmonic) of the microbubbles were successfully detected. Moreover, images from a flow phantom were acquired and demonstrated the potential of the transducer for high-frequency nonlinear contrast imaging.

  6. Dual-frequency super harmonic imaging piezoelectric transducers for transrectal ultrasound

    Science.gov (United States)

    Kim, Jinwook; Li, Sibo; Kasoji, Sandeep; Dayton, Paul A.; Jiang, Xiaoning

    2015-03-01

    In this paper, a 2/14 MHz dual-frequency single-element transducer and a 2/22 MHz sub-array (16/48-elements linear array) transducer were developed for contrast enhanced super-harmonic ultrasound imaging of prostate cancer with the low frequency ultrasound transducer as a transmitter for contrast agent (microbubble) excitation and the high frequency transducer as a receiver for detection of nonlinear responses from microbubbles. The 1-3 piezoelectric composite was used as active materials of the single-element transducers due to its low acoustic impedance and high coupling factor. A high dielectric constant PZT ceramic was used for the sub-array transducer due to its high dielectric property induced relatively low electrical impedance. The possible resonance modes of the active elements were estimated using finite element analysis (FEA). The pulse-echo response, peak-negative pressure and bubble response were tested, followed by in vitro contrast imaging tests using a graphite-gelatin tissue-mimicking phantom. The single-element dual frequency transducer (8 × 4 × 2 mm3) showed a -6 dB fractional bandwidth of 56.5% for the transmitter, and 41.8% for the receiver. A 2 MHz-transmitter (730 μm pitch and 6.5 mm elevation aperture) and a 22 MHz-receiver (240 μm pitch and 1.5 mm aperture) of the sub-array transducer exhibited -6 dB fractional bandwidth of 51.0% and 40.2%, respectively. The peak negative pressure at the far field was about -1.3 MPa with 200 Vpp, 1-cycle 2 MHz burst, which is high enough to excite microbubbles for nonlinear responses. The 7th harmonic responses from micro bubbles were successfully detected in the phantom imaging test showing a contrast-to-tissue ratio (CTR) of 16 dB.

  7. 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.

  8. DUAL-FOCUS THERAPEUTIC ULTRASOUND TRANSDUCER FOR PRODUCTION OF BROAD TISSUE LESIONS

    Science.gov (United States)

    Jeong, Jong Seob; Cannata, Jonathan M.; Shung, K. Kirk

    2011-01-01

    In noninvasive high-intensity focused ultrasound (HIFU) treatment, formation of a large tissue lesion per sonication is desirable for reducing the overall treatment time. The goal of this study is to show the feasibility of enlarging tissue lesion size with a dual-focus therapeutic ultrasound transducer (DFTUT) by increasing the depth-of-focus (DOF). The proposed transducer consists of a disc- and an annular-type element of different radii of curvatures to produce two focal zones. To increase focal depth and to maintain uniform beamwidth of the elongated DOF, each element transmits ultrasound of a different center frequency: the inner element at a higher frequency for near field focusing and the outer element at a lower frequency for far field focusing. By activating two elements at the same time with a single transmitter capable of generating a dual-frequency mixed signal, the overall DOF of the proposed transducer may be extended considerably. A prototype transducer composed of a 4.1 MHz inner element and a 2.7 MHz outer element was fabricated to obtain preliminary experimental results. The feasibility the proposed technique was demonstrated through sound field, temperature and thermal dose simulations. The performance of the prototype transducer was verified by hydrophone measurements and tissue ablation experiments on a beef liver specimen. When several factors affecting the length and the uniformity of elongated DOF of the DFTUT are optimized, the proposed therapeutic ultrasound transducer design may increase the size of ablated tissues in the axial direction and, thus, decreasing the treatment time for a large volume of malignant tissues especially deep-seated targets. PMID:20870346

  9. 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

  10. 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

  11. 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.

  12. 7.5 MHz dual-layer transducer array for 3-D rectilinear imaging.

    Science.gov (United States)

    Chen, Yuling; Nguyen, Man; Yen, Jesse T

    2011-07-01

    The difficulties associated with fabrication and interconnection have limited the development of 2-D ultrasound transducer arrays with a large number ofelements (>5000). In previous work, we described a 5 MHz center frequency PZT-P[VDF-TrFE] dual-layer transducer that used two perpendicular 1-D arrays for 3-D rectilinear imaging. This design substantially reduces the channel count as well as fabrication complexity, which makes 3-D imaging more realizable. Higher frequencies (>5 MHz) are more commonly used in clinical applications or imaging targets near transducers, such as the breast, carotid and musculoskeletal tissue. In this paper, we present a 7.5 MHz dual-layer transducer array for 3-D rectilinear imaging. A modified acoustic stack model was designed and fabricated. PZT elements were sub-diced to eliminate lateral coupling. This sub-dicing process made the PZT into a 2-2 composite material, which could help improve transducer sensitivity and bandwidth. Full synthetic-aperture 3-D data sets were acquired by interfacing the transducer with a Verasonics data-acquisition system (VDAS). Offline 3-D beamforming was then performed to obtain volumes of a multiwire phantom and a cyst phantom. The generalized coherence factor (GCF) was applied to improve the contrast of cyst images. The measured -6 dB fractional bandwidth of the transducer was 71% with a center frequency of 7.5 MHz. The measured lateral beamwidths were 0.521 mm and 0.482 mm in azimuth and elevation, respectively, compared with a simulated beamwidth of 0.43 mm.

  13. 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.

  14. 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

  15. A dual-layer transducer array for 3-D rectilinear imaging.

    Science.gov (United States)

    Yen, Jesse T; Seo, Chi Hyung; Awad, Samer I; Jeong, Jong S

    2009-01-01

    Very large element counts (16,000-65,000) are required for 2-D arrays for 3-D rectilinear imaging. The difficulties in fabricating and interconnecting 2-D arrays with a large number of elements (>5,000) have limited the development of suitable transducers for 3-D rectilinear imaging. In this paper, we propose an alternative solution to this problem by using a dual-layer transducer array design. This design consists of 2 perpendicular 1-D arrays for clinical 3-D imaging of targets near the transducer. These targets include the breast, carotid artery, and musculoskeletal system. This transducer design reduces the fabrication complexity and the channel count, making 3-D rectilinear imaging more realizable. With this design, an effective N x N 2-D array can be developed using only N transmitters and N receivers. This benefit becomes very significant when N becomes greater than 128, for example. To demonstrate feasibility, we constructed a 4 x 4 cm prototype dual-layer array. The transmit array uses diced PZT-5H elements, and the receive array is a single sheet of undiced P[VDF-TrFE] copolymer. The receive elements are defined by the copper traces on the flexible interconnect circuit. The measured -6 dB fractional bandwidth was 80% with a center frequency of 4.8 MHz. At 5 MHz, the nearest neighbor crosstalk of the PZT array and PVDF array was -30.4 +/- 3.1 dB and -28.8 +/- 3.7 dB, respectively. This dual-layer transducer was interfaced with an Ultrasonix Sonix RP system, and a synthetic aperture 3-D data set was acquired. We then performed offline 3-D beamforming to obtain volumes of nylon wire targets. The theoretical lateral beamwidth was 0.52 mm compared with measured beamwidths of 0.65 mm and 0.67 mm in azimuth and elevation, respectively. Then, 3-D images of an 8 mm diameter anechoic cyst phantom were also acquired.

  16. A new three-dimensional electromechanical impedance model for an embedded dual-PZT transducer

    Science.gov (United States)

    Wang, Dansheng; Li, Zhi; Zhu, Hongping

    2016-07-01

    In the past twenty years, the electromechanical (EM) impedance technique has been investigated extensively in the mechanical, aviation and civil engineering fields. Many different EM impedance models have been proposed to characterize the interaction between the surface-bonded PZT transducer and the host structure. This paper formulates a new three-dimensional EM impedance model characterizing the interaction between an embedded circle dual-PZT transducer and the host structure based on the effective impedance concept. The proposed model is validated by experimental results from a group of smart cement cubes, in which three circle dual-PZT transducers are embedded respectively. In addition, a new EM impedance measuring method for the dual-PZT transducer is also introduced. In the measuring method, only a common signal generator and an oscilloscope are needed, by which the exciting and receiving voltage signals are obtained respectively. Combined with fast Fourier transform the EM impedance signatures of the dual-PZT transducers are obtained.

  17. The prediction of transducer element performance from in air measurements

    Science.gov (United States)

    Schafer, M. E.

    1982-01-01

    A technique has been developed which accurately predicts the performance of underwater acoustic arrays prior to array construction. The technique is based upon the measurement of lumped-parameter equivalent circuit values for each element in the array, and is accurate in predicting the array transmit, receive and beam pattern response. The measurement procedure determines the shunt electrical and motional circuit elements from electrical imittance measurements. The electromechanical transformation ratio is derived from in-air measurements of the radiating face velocity and the input current to the transducer at resonance. The equivalent circuit values of a group of Tonpilz-type transducers were measured, and the self and mutual interaction acoustic loadings for a specific array geometry were calculated. The response of the elements was then predicted for water-loaded array conditions. Based on the predictions, a selection scheme was developed which minimized the effects of inter-element variability on array performance. The measured transmitting, receiving and beam pattern characteristics of a test array, built using the selected elements, were compared to predictions made before the array was built. The results indicated that the technique is accurate over a wide frequency range.

  18. 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.

  19. Single-transducer dual-frequency ultrasound generation to enhance acoustic cavitation.

    Science.gov (United States)

    Liu, Hao-Li; Hsieh, Chao-Ming

    2009-03-01

    Dual- or multiple-frequency ultrasound stimulation is capable of effectively enhancing the acoustic cavitation effect over single-frequency ultrasound. Potential application of this sonoreactor design has been widely proposed such as on sonoluminescence, sonochemistry enhancement, and transdermal drug release enhancement. All currently available sonoreactor designs employed multiple piezoelectric transducers for generating single-frequency ultrasonic waves separately and then these waves were mixed and interfered in solutions. The purpose of this research is to propose a novel design of generating dual-frequency ultrasonic waves with single piezoelectric elements, thereby enhancing acoustic cavitation. Macroscopic bubbles were detected optically, and they were quantified at either a single-frequency or for different frequency combinations for determining their efficiency for enhancing acoustic cavitation. Visible bubbles were optically detected and hydrogen peroxide was measured to quantify acoustic cavitation. Test water samples with different gas concentrations and different power levels were used to determine the efficacy of enhancing acoustic cavitation of this design. The spectrum obtained from the backscattered signals was also recorded and examined to confirm the occurrence of stable cavitation. The results confirmed that single-element dual-frequency ultrasound stimulation can enhance acoustic cavitation. Under certain testing conditions, the generation of bubbles can be enhanced up to a level of five times higher than the generation of bubbles in single-frequency stimulation, and can increase the hydrogen peroxide production up to an increase of one fold. This design may serve as a useful alternative for future sonoreactor design owing to its simplicity to produce dual- or multiple-frequency ultrasound.

  20. 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...

  1. Design factors of intravascular dual frequency transducers for super-harmonic contrast imaging and acoustic angiography

    Science.gov (United States)

    Ma, Jianguo; Martin, K. Heath; Li, Yang; Dayton, Paul A.; Shung, K. Kirk; Zhou, Qifa; Jiang, Xiaoning

    2015-01-01

    Imaging of coronary vasa vasorum may lead to assessment of the vulnerable plaque development in diagnosis of atherosclerosis diseases. Dual frequency transducers capable of detection of microbubble super-harmonics have shown promise as a new contrast-enhanced intravascular ultrasound (CE-IVUS) platform with the capability of vasa vasorum imaging. Contrast-to-tissue ratio (CTR) in CE-IVUS imaging can be closely associated with the low frequency transmitter performance. In this paper, transducer designs encompassing different transducer layouts, transmitting frequencies, and transducer materials are compared for optimization of imaging performance. In the layout selection, the stacked configuration showed superior super-harmonic imaging compared with the interleaved configuration. In the transmitter frequency selection, a decrease in frequency from 6.5 MHz to 5 MHz resulted in an increase of CTR from 15 dB to 22 dB when receiving frequency was kept constant at 30 MHz. In the material selection, the dual frequency transducer with the lead magnesium niobate-lead titanate (PMN-PT) 1-3 composite transmitter yielded higher axial resolution compared to single crystal transmitters (70 μm compared to 150 μm pulse length). These comparisons provide guidelines for design of intravascular acoustic angiography transducers. PMID:25856384

  2. Thermal Control of a Dual Mode Parametric Sapphire Transducer

    CERN Document Server

    Belfi, Jacopo; De Michele, Andrea; Gabbriellini, Gianluca; Mango, Francesco; Passaquieti, Roberto

    2010-01-01

    We propose a method to control the thermal stability of a sapphire dielectric transducer made with two dielectric disks separated by a thin gap and resonating in the whispering gallery (WG) modes of the electromagnetic field. The simultaneous measurement of the frequencies of both a WGH mode and a WGE mode allows one to discriminate the frequency shifts due to gap variations from those due to temperature instability. A simple model, valid in quasi equilibrium conditions, describes the frequency shift of the two modes in terms of four tuning parameters. A procedure for the direct measurement of them is presented.

  3. Dual-frequency transducer with a wideband PVDF receiver for contrast-enhanced, adjustable harmonic imaging

    Science.gov (United States)

    Kim, Jinwook; Lindsey, Brooks D.; Li, Sibo; Dayton, Paul A.; Jiang, Xiaoning

    2017-04-01

    Acoustic angiography is a contrast-enhanced, superharmonic microvascular imaging method. It has shown the capability of high-resolution and high-contrast-to-tissue-ratio (CTR) imaging for vascular structure near tumor. Dual-frequency ultrasound transducers and arrays are usually used for this new imaging technique. Stacked-type dual-frequency transducers have been developed for this vascular imaging method by exciting injected microbubble contrast agent (MCA) in the vessels with low-frequency (1-5 MHz), moderate power ultrasound burst waves and receiving the superharmonic responses from MCA by a high-frequency receiver (>10 MHz). The main challenge of the conventional dual-frequency transducers is a limited penetration depth (harmonic signal detection. A receiver with a high receiving sensitivity spanning a wide superharmonic frequency range (3rd to 6th) enables selectable bubble harmonic detection considering the required penetration depth. Here, we develop a new dual-frequency transducer composed of a 2 MHz 1-3 composite transmitter and a polyvinylidene fluoride (PVDF) receiver with a receiving frequency range of 4-12 MHz for adjustable harmonic imaging. The developed transducer was tested for harmonic responses from a microbubble-injected vessel-mimicking tube positioned 45 mm away. Despite the long imaging distance (45 mm), the prototype transducer detected clear harmonic response with the contrast-to-noise ratio of 6-20 dB and the -6 dB axial resolution of 200-350 μm for imaging a 200 um-diameter cellulose tube filled with microbubbles.

  4. Handheld probe integrating laser diode and ultrasound transducer array for ultrasound/photoacoustic dual modality imaging.

    Science.gov (United States)

    Daoudi, K; van den Berg, P J; Rabot, O; Kohl, A; Tisserand, S; Brands, P; Steenbergen, W

    2014-10-20

    Ultrasound and photoacoustics can be utilized as complementary imaging techniques to improve clinical diagnoses. Photoacoustics provides optical contrast and functional information while ultrasound provides structural and anatomical information. As of yet, photoacoustic imaging uses large and expensive systems, which limits their clinical application and makes the combination costly and impracticable. In this work we present and evaluate a compact and ergonomically designed handheld probe, connected to a portable ultrasound system for inexpensive, real-time dual-modality ultrasound/photoacoustic imaging. The probe integrates an ultrasound transducer array and a highly efficient diode stack laser emitting 130 ns pulses at 805 nm wavelength and a pulse energy of 0.56 mJ, with a high pulse repetition frequency of up to 10 kHz. The diodes are driven by a customized laser driver, which can be triggered externally with a high temporal stability necessary to synchronize the ultrasound detection and laser pulsing. The emitted beam is collimated with cylindrical micro-lenses and shaped using a diffractive optical element, delivering a homogenized rectangular light intensity distribution. The system performance was tested in vitro and in vivo by imaging a human finger joint.

  5. Fas transduces dual apoptotic and trophic signals in hematopoietic progenitors.

    Science.gov (United States)

    Pearl-Yafe, Michal; Stein, Jerry; Yolcu, Esma S; Farkas, Daniel L; Shirwan, Haval; Yaniv, Isaac; Askenasy, Nadir

    2007-12-01

    Stem cells and progenitors are often required to realize their differentiation potential in hostile microenvironments. The Fas/Fas ligand (FasL) interaction is a major effector pathway of apoptosis, which negatively regulates the expansion of differentiated hematopoietic cells. The involvement of this molecular interaction in the function of hematopoietic stem and progenitor cells is not well understood. In the murine syngeneic transplant setting, both Fas and FasL are acutely upregulated in bone marrow-homed donor cells; however, the Fas(+) cells are largely insensitive to FasL-induced apoptosis. In heterogeneous populations of lineage-negative (lin(-)) bone marrow cells and progenitors isolated by counterflow centrifugal elutriation, trimerization of the Fas receptor enhanced the clonogenic activity. Inhibition of caspases 3 and 8 did not affect the trophic signals mediated by Fas, yet it efficiently blocked the apoptotic pathways. Fas-mediated tropism appears to be of physiological significance, as pre-exposure of donor cells to FasL improved the radioprotective qualities of hematopoietic progenitors, resulting in superior survival of myeloablated hosts. Under these conditions, the activity of long-term reconstituting cells was not affected, as determined in sequential secondary and tertiary transplants. Dual caspase-independent tropic and caspase-dependent apoptotic signaling place the Fas receptor at an important junction of activation and death. This regulatory mechanism of hematopoietic homeostasis activates progenitors to promote the recovery from aplasia and converts into a negative regulator in distal stages of cell differentiation. Disclosure of potential conflicts of interest is found at the end of this article.

  6. Dual-radial cell thermionic fuel element

    Science.gov (United States)

    Terrell, Charles W.

    A dual-radial cell thermionic fuel element (TFE) has been proposed and partially evaluated. The cell has the capacity to produce considerably more power per gram of fuel than does a single-cell TFE, with a total electrical power in a fast reactor system of several hundred kWs, conservatively operated.

  7. Synthetic Aperture Focusing for a Single Element Transducer undergoing Helix Motion

    DEFF Research Database (Denmark)

    Andresen, Henrik; Nikolov, Svetoslav Ivanov; Jensen, Jørgen Arendt

    2011-01-01

    This paper describes the application of 3D synthetic aperture focusing (SAF) to a single element trans-rectal ultrasound transducer. The transducer samples a 3D volume by simultaneous rotation and translation giving a helix motion. Two different 3D SAF methods are investigated, a direct and a two...

  8. Development of dual PZT transducers for reference-free crack detection in thin plate structures.

    Science.gov (United States)

    Sohn, Hoon; Kim, Seuno Bum

    2010-01-01

    A new Lamb-wave-based nondestructive testing (NDT) technique, which does not rely on previously stored baseline data, is developed for crack monitoring in plate structures. Commonly, the presence of damage is identified by comparing "current data" measured from a potentially damaged stage of a structure with "baseline data" previously obtained at the intact condition of the structure. In practice, structural defects typically take place long after collection of the baseline data, and the baseline data can be also affected by external loading, temperature variations, and changing boundary conditions. To eliminate the dependence on the baseline data comparison, the authors previously developed a reference-free NDT technique using 2 pairs of collocated lead zirconate titanate (PZT) transducers placed on both sides of a plate. This reference-free technique is further advanced in the present study by the necessity of attaching transducers only on a single surface of a structure for certain applications such as aircraft. To achieve this goal, a new design of PZT transducers called dual PZT transducers is proposed. Crack formation creates Lamb wave mode conversion due to a sudden thickness change of the structure. This crack appearance is instantly detected from the measured Lamb wave signals using the dual PZT transducers. This study also suggests a reference-free statistical approach that enables damage classification using only the currently measured data set. Numerical simulations and experiments were conducted using an aluminum plate with uniform thickness and fundamental Lamb waves modes to demonstrate the applicability of the proposed technique to reference-free crack detection.

  9. Design of an optical-fiber refractometric transducer with hemispherical detection element

    OpenAIRE

    2006-01-01

    We analyzed the performance of the opticalfiber refractometric transducer with hemispherical optical detection element. Specifically, we examined the effect of the light intensity distribution in the optical fibers on the transducer response to the refractive index of the surrounding media. In addition, we accounted for small local imperfections of the optical detection element surface. Accounting for these effects results in a significant accuracy improvement in the modeling of the described...

  10. Analysis of acoustic impedance matching in dual-band ultrasound transducers.

    Science.gov (United States)

    Myhre, Ola Finneng; Johansen, Tonni Franke; Johan Angelsen, Bjørn Atle

    2017-02-01

    Dual-frequency band probes are needed for ultrasound (US) reverberation suppression and are useful for image-guided US therapy. A challenge is to design transducer stacks that achieve high bandwidth and efficiency at both operating frequencies when the frequencies are widely separated with a frequency ratio ∼6:1-20:1. This paper studies the loading and backing conditions of transducers in such stacks. Three stack configurations are presented and analyzed using one-dimensional models. It is shown that a configuration with three layers of material separating the transducers is favorable, as it reduces high frequency ringing by ∼20 dB compared to other designs, and matches the low frequency (LF) transducer to the load at a lower frequency. In some cases, the LF load matching is governed by a simple mass-spring interaction in spite of having a complicated matching structure. The proposed design should yield improved performance of reverberation suppression algorithms. Its suitability for reduction of probe heating, also in single-band probes, should be investigated.

  11. 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.

  12. Surface acoustic wave nebulization device with dual interdigitated transducers improves SAWN-MS performance.

    Science.gov (United States)

    Huang, Yue; Heron, Scott R; Clark, Alicia M; Edgar, J Scott; Yoon, Sung Hwan; Kilgour, David P A; Turecek, Frantisek; Aliseda, Alberto; Goodlett, David R

    2016-06-01

    We compared mass spectrometric (MS) performance of surface acoustic wave nebulization (SAWN) generated by a single interdigitated transducer (IDT) designed to produce a progressive wave (PW) to one with a dual IDT that can in theory generate standing waves (SW). Given that devices using dual IDTs had been shown to produce fewer large size droplets on average, we hypothesized they would improve MS performance by improving the efficiency of desolvation. Indeed, the SW-SAWN chip provided an improved limit of detection of 1 femtomole of peptide placed on chip making it 100× more sensitive than the PW design. However, as measured by high-speed image recording and phase Doppler particle analyzer measurements, there was only a 26% increase in the small diameter (1-10 µm) droplets produced from the new device, precluding a conclusion that the decrease in droplet size was solely responsible for the improvement in MS signal/noise. Given that the dual IDT design produced a more instantaneous plume than the PW design, the more likely contributor to improved MS signal/noise was concluded to be a higher ion flux entering the mass spectrometer for the dual IDT designs. Notably, the dual IDT device allowed production of much higher quality protein mass spectra up to about 20 kDa, compared with the single IDT device. Copyright © 2016 John Wiley & Sons, Ltd.

  13. Analysis of piezoelectric ultrasonic transducers attached to waveguides using waveguide finite elements.

    Science.gov (United States)

    Loveday, Philip W

    2007-10-01

    A finite-element modeling procedure for computing the frequency response of piezoelectric transducers attached to infinite constant cross-section waveguides, as encountered in guided wave ultrasonic inspection, is presented. Two-dimensional waveguide finite elements are used to model the waveguide. Conventional three-dimensional finite elements are used to model the piezoelectric transducer. The harmonic forced response of the waveguide is used to obtain a dynamic stiffness matrix (complex and frequency dependent), which represents the waveguide in the transducer model. The electrical and mechanical frequency response of the transducer, attached to the waveguide, can then be computed. The forces applied to the waveguide are calculated and are used to determine the amplitude of each mode excited in the waveguide. The method is highly efficient compared to time integration of a conventional finite-element model of a length of waveguide. In addition, the method provides information about each mode that is excited in the waveguide. The method is demonstrated by modeling a sandwich piezoelectric transducer exciting a waveguide of rectangular cross section, although it could be applied to more complex situations. It is expected that the modeling method will be useful during the optimization of piezoelectric transducers for exciting specific wave propagation modes in waveguides.

  14. Finite element simulation of single ultrasonic transducer with segmented electrodes to adjust the directional characteristic

    Science.gov (United States)

    Unverzagt, Carsten; Henning, Bernd

    2012-05-01

    For many applications like level measurement and industry robotics it is of advantage if the directional characteristic of an ultrasonic transducer is changeable or adaptable for the improvement of spatial resolution. Often this goal is reached with the use of ultrasonic transducer arrays, which elements are driven with phase shifted excitation signals. One disadvantage of these solutions is the great effort for building such an array and the multi-channel sensor electronics. In this contribution the directional characteristic of a single air transducer with segmented electrodes is analyzed. Therefore a variable script based finite element model is used to discover the influence of different electrode configurations on the directional characteristic of a single piezoceramic transducer. Especially the influence on the angle of beam and the near field length are evaluated. The used variable model permits an optimization of the configuration with regards to the mentioned criteria. The findings will be used for the development of a level measurement system for bulk solids.

  15. User manual for ATILA, a finite-element code for modeling piezoelectric transducers

    Science.gov (United States)

    Decarpigny, Jean-Noel; Debus, Jean-Claude

    1987-09-01

    This manual for the user of the finite-element code ATILA provides instruction for entering information and running the code on a VAX computer. The manual does not include the code. The finite element code ATILA has been specifically developed to aid the design of piezoelectric devices, mainly for sonar applications. Thus, it is able to perform the model analyses of both axisymmetrical and fully three-dimensional piezoelectric transducers. It can also provide their harmonic response under radiating conditions: nearfield and farfield pressure, transmitting voltage response, directivity pattern, electrical impedance, as well as displacement field, nodal plane positions, stress field and various stress criteria...Its accuracy and its ability to describe the physical behavior of various transducers (Tonpilz transducers, double headmass symmetrical length expanders, free flooded rings, flextensional transducers, bender bars, cylindrical and trilaminar hydrophones...) have been checked by modelling more than twenty different structures and comparing numerical and experimental results.

  16. Analysis and design of piezocomposite ultrasonic transducers using finite element technique and surface displacement profiles

    CERN Document Server

    Reynolds, P

    2000-01-01

    Ultrasonic transducers have found extensive applications in the fields of non-destructive testing, biomedicine, and SONAR. Piezocomposite ultrasonic transducers can offer significant advantages over their pure ceramic counterparts, but at the expense of increased manufacturing complexity and the introduction of additional resonant modes that may reduce transducer efficiency if the device is not carefully designed. Extensive work has been carried out over the last twenty years to characterise the behaviour of piezocomposite devices, resulting in many design guidelines, some of which are only applicable in a limited range of device structures. This Thesis presents a new theory of the generation of inter-pillar modes that is based upon the generation of Lamb waves in the piezocomposite plate. Through the use of finite element analysis and a scanning laser interferometer, the resonant mode displacement shapes of piezocomposite transducers are studied and analysed. Excellent correlation between modelled and experi...

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

    Science.gov (United States)

    2005-08-15

    and Mass Transfer, Addison-Wesley, Reading MA, 1988. 12. G. Arfken , Mathematical Methods for Physicists, Academic Press, 1985. 13. "FLUX2D...Electromagnetic and Thermal Analysis 2-D Finite Element Program," Magsoft Corporation, Troy, NY. 14. G. B. Arfken , D. F. Griffing, D. C. Kelly, and J. Priest

  18. A Dual Ridge Broadband Orthomode Transducer for the 7-mm Band

    Science.gov (United States)

    Reyes, Nicolas; Zorzi, Pablo; Pizarro, Jose; Finger, Ricardo; Mena, F. Patricio; Bronfman, Leonardo

    2012-12-01

    In this work we present a Q-band waveguide orthomode transducer (OMT) based on a dual ridge structure. It was designed to be used in astronomical projects were an excellent broad-band performance is mandatory. Of particular interest is the case of ALMA Band 1 (originally set at 31-45 GHz) project which will need several OMTs with outstanding performance and demonstrated manufacturability. By using a symmetrical structure, low cross-polar level and good input matching are achieved over a broad bandwidth (37 %). The proposed design incorporates an octagonal mode converter which allows the unit to be directly mated with the horn avoiding cross-polar issues at the interface. The OMT was designed to have a compact configuration and easiness of fabrication, both crucial features in projects where several units (up to 70) have to be constructed.

  19. Radiation and scattering analysis of piezoelectric transducers using finite and infinite wave envelope elements

    Science.gov (United States)

    Kim, Jaehwan; Jung, Eunmi; Choi, Seung-Bok

    2002-07-01

    This paper presents a numerical modeling technique of piezoelectric transducers by taking into account wave radiation and scattering. It is based on the finite element modeling. Coupling problems between piezoelectric and elastic materials as well as fluid and structure systems associated with the modeling of piezoelectric underwater acoustic sensors are formulated. In the finite element modeling of unbounded acoustic fluid, IWEE (Infinite Wave Envelop Element) is adopted to take into account the infinite domain. The IWEE code is added to an in-house finite element program, and commercial pre and post-processor are used for mesh generation and to see the output. The validation of the numerical modeling is proved through an example, and scattering and radiation analysis of Tonpilz transducer is performed. The scattered wave on the sensor is calculated, and the sensor response, so called RVS (Receiving Voltage Sensitivity) is predicted.

  20. Dual Career Marriages: Elements for Potential Success.

    Science.gov (United States)

    Maples, Mary F.

    1981-01-01

    Examines the family and work relationships of dual career couples and discusses the advantages and disadvantages of these relationships. Various ingredients including personality traits that contribute to the success of the two-career partnership are listed. (RC)

  1. Single-element focused ultrasound transducer method for harmonic motion imaging.

    Science.gov (United States)

    Maleke, Caroline; Pernot, Mathieu; Konofagou, Elisa E

    2006-07-01

    The harmonic motion imaging (HMI) technique for simultaneous monitoring and generation of ultrasound therapy using two separate focused ultrasound transducer elements was previously demonstrated. In this study, a new HMI technique is described that images tissue displacement induced by a harmonic radiation force using a single focused-ultrasound element. A wave propagation simulation model first indicated that, unlike in the two-beam configuration, the amplitude-modulated beam produced a stable focal zone for the applied harmonic radiation force. The AM beam thus offered the unique advantage of sustaining the application of the spatially-invariant radiation force. Experiments were performed on gelatin phantoms and ex vivo tissues. The radiation force was generated by a 4.68 MHz focused ultrasound (FUS) transducer using a 50 Hz amplitude-modulated wave. A 7.5 MHz pulse-echo transducer was used to acquire rf echoes during the application of the harmonic radiation force. Consecutive rf echoes were acquired with a pulse repetition frequency (PRF) of 6.5 kHz and 1D cross-correlation was performed to estimate the resulting axial tissue displacement. The HMI technique was shown capable of estimating stiffness-dependent displacement amplitudes. Finally, taking advantage of the real-time capability of the HMI technique, temperature-dependent measurements enabled monitoring ofHIFU sonication in ex vivo tissues. The new HMI method may thus enable a highly-localized force and stiffness-dependent measurements as well as real-time and low-cost HIFU monitoring.

  2. An NLRA Transducer for Dual Use Bone Conduction Audio and Haptic Communication. Summary Report

    Science.gov (United States)

    2016-12-30

    component. Initially developed to enable the most precise haptic communication components, NLRA technology has the potential to create a combined...transducer core capable of both precise haptic communication and high fidelity bone conduction audio. The transducer design leverages Micro-Multilayer...Its ideal use is as a component of a head-mounted communication system for CBRNE and Special Operations Forces exposed to many simultaneous sensory

  3. An Airborne Ultrasonic Imaging System Based on 16 Elements: 150 kHz Piezopolymer Transducer Arrays—Preliminary Simulated and Experimental Results for Cylindrical Targets Detection

    Science.gov (United States)

    Capineri, L.; Bulletti, A.; Calzolai, M.; Giannelli, P.

    2016-12-01

    This paper describes the design and fabrication of a 16-element transducer array for airborne ultrasonic imaging operating at 150 kHz, that can operate both at close range (50 mm) in the near field of a synthetic aperture, and up to 250 mm. The proposed imaging technique is based on a modified version of the delay and sum algorithm implemented with a synthetic aperture where each pixel amplitude is determined by the integration of the signal obtained by the coherent summation of the acquired signals over a delayed window with fixed length. The image reconstruction methods using raw data provides the possibility to detect targets with smaller feature size on the order of one wavelength because the coherent signals summation over the selected window length while the image reconstruction methods using the summation of enveloped signals increases the amplitude response at the expenses of a lower spatial resolution. For the implementation of this system it is important to design compact airborne transducers with large field of view and this can be obtained with a new design of hemi-cylindrical polyvinylidene fluoride film transducers directly mounted on a printed circuit board. This new method is low cost and has repeatable transducer characteristics. The complete system is compact, with a modular architecture, in which eight boards with dual ultrasonic channels are mounted on a mother board. Each daughter board hosts a microcontroller unit and can operate with transducers in the bandwidth 40-200 kHz with on-board data acquisition, pre-processing and transfer on a dedicated bus.

  4. Dual Formulations of Mixed Finite Element Methods with Applications.

    Science.gov (United States)

    Gillette, Andrew; Bajaj, Chandrajit

    2011-10-01

    Mixed finite element methods solve a PDE using two or more variables. The theory of Discrete Exterior Calculus explains why the degrees of freedom associated to the different variables should be stored on both primal and dual domain meshes with a discrete Hodge star used to transfer information between the meshes. We show through analysis and examples that the choice of discrete Hodge star is essential to the numerical stability of the method. Additionally, we define interpolation functions and discrete Hodge stars on dual meshes which can be used to create previously unconsidered mixed methods. Examples from magnetostatics and Darcy flow are examined in detail.

  5. Development of Optical Voltage Transducer Based on Dual-Mode Highly Elliptical-Core Polarization Maintenance Fiber

    Institute of Scientific and Technical Information of China (English)

    Wei-Hong Bi; Feng Liu; Xuan Guo

    2008-01-01

    This paper describes an optical voltage transducer (OVT) for the 35 kV electric power system based on modular interference in dual-mode highly elliptical-core polarization maintenance fiber (E-Core PMIF). The temperature and environmental perturb-bation can be compensated automatically. In the scheme, a quartz crystal cylinder wrapped with highly elliptical-core fiber plays the role of voltage sensor head. The two interference output lobes' intensity from the E-core PMF is modulated with the converse piezoelectric effect of quartz crystal. A PZT wrapped with E-core PMF at ground potential serves as the static modular phase difference control and temperature compensation unit. The experiment results indicate that the OVT designed in this paper has satisfying performance and could successfully rejects the temperature perturbation.

  6. Scattering by single physically large and weak scatterers in the beam of a single-element transducer.

    Science.gov (United States)

    Kemmerer, Jeremy P; Oelze, Michael L; Gyöngy, Miklós

    2015-03-01

    Quantitative ultrasound techniques are generally applied to characterize media whose scattering sites are considered to be small compared to a wavelength. In this study, the backscattered response of single weakly scattering spheres and cylinders with diameters comparable to the beam width of a 2.25 MHz single-element transducer were simulated and measured in the transducer focal plane to investigate the impact of physically large scatterers. The responses from large single spherical scatterers at the focus were found to closely match the plane-wave response. The responses from large cylindrical scatterers at the focus were found to differ from the plane-wave response by a factor of f(-1). Normalized spectra from simulations and measurements were in close agreement: the fall-off of the responses as a function of lateral position agreed to within 2 dB for spherical scatterers and to within 3.5 dB for cylindrical scatterers. In both measurement and simulation, single scatterer diameter estimates were biased by less than 3% for a more highly focused transducer compared to estimates for a more weakly focused transducer. The results suggest that quantitative ultrasound techniques may produce physically meaningful size estimates for media whose response is dominated by scatterers comparable in size to the transducer beam.

  7. Acoustic transducer

    Science.gov (United States)

    Drumheller, Douglas S.

    2000-01-01

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

  8. 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.

  9. A Dual Super-Element Domain Decomposition Approach for Parallel Nonlinear Finite Element Analysis

    Science.gov (United States)

    Jokhio, G. A.; Izzuddin, B. A.

    2015-05-01

    This article presents a new domain decomposition method for nonlinear finite element analysis introducing the concept of dual partition super-elements. The method extends ideas from the displacement frame method and is ideally suited for parallel nonlinear static/dynamic analysis of structural systems. In the new method, domain decomposition is realized by replacing one or more subdomains in a "parent system," each with a placeholder super-element, where the subdomains are processed separately as "child partitions," each wrapped by a dual super-element along the partition boundary. The analysis of the overall system, including the satisfaction of equilibrium and compatibility at all partition boundaries, is realized through direct communication between all pairs of placeholder and dual super-elements. The proposed method has particular advantages for matrix solution methods based on the frontal scheme, and can be readily implemented for existing finite element analysis programs to achieve parallelization on distributed memory systems with minimal intervention, thus overcoming memory bottlenecks typically faced in the analysis of large-scale problems. Several examples are presented in this article which demonstrate the computational benefits of the proposed parallel domain decomposition approach and its applicability to the nonlinear structural analysis of realistic structural systems.

  10. Design, simulation and testing of capacitive micromachined ultrasound transducer-based phospholipidic biosensor elements

    Science.gov (United States)

    Sapeliauskas, E.; Vanagas, G.; Barauskas, D.; Mikolajunas, M.; Pakenas, E.; Pelenis, D.; Sergalis, G.; Jukna, T.; Virzonis, D.

    2015-07-01

    In this study we present theoretical proof of the principle of using interdigital capacitive micromachined ultrasound transducers (CMUT IDTs) for the detection of phospholipid membrane elasticity. Proof of principle was needed to find out whether the new type of microelectromechanical sensors of the toxins incorporated with the lipid membranes was feasible. CMUT IDTs for 10 MHz operation in water, with 146 µm spaced double fingers were designed and fabricated using the surface micromachining technique. Fabricated CMUTs were tested for their resonance in air and for Scholte-type wave transmission in deionized water and isopropanol solutions containing 0%, 10% and 20% water. The amplitude and phase velocity of the excited and received Scholte waves were measured in a 200 µm height microchannel, capped with a thick layer of soft polymer, which suppressed the production of non-informative guided waves. It was determined that the average sensitivity of Scholte wave phase velocity within the given range of solution concentrations is 2.9 m s-1 per one percent. Experimental data were also used to verify the adequacy of the finite element model, which was found to be suitable for reliable prediction of the phospholipid membrane elasticity impact on the Scholte wave phase velocity or the resonance frequency in the present IDT structure. It was determined that for the analyzed conditions (the elasticity of simulated phospholipid membrane changed from 1 to 5 GPa) the sensitivity of the measurement channel is expected to be no worse than 2 kHz GPa-1 in terms of the Scholte wave and CMUT IDT resonance frequency. This leads to a positive conclusion on the feasibility of the new sensor type.

  11. Dual-side backward coupler waveguide orthomode transducer for the 3 mm band

    Science.gov (United States)

    Navarrini, Alessandro; Nesti, Renzo

    2008-07-01

    We describe the design, construction, and characterization results of a waveguide Orthomode Transducer (OMT) for the 3 mm band (84-116 GHz.) The OMT is based on a symmetric backward coupling structure and has a square waveguide input port (2.54 mm × 2.54 mm) and two single-mode waveguide outputs: a standard WR10 rectangular waveguide (2.54 mm × 1.27 mm,) and an oval waveguide with full-radius corners. The reverse coupling structure is located in the common square waveguide arm and splits one polarization signal in two opposite rectangular waveguide sidearms using broadband -3 dB E-plane branch-line hybrid couplers. The device was optimized using a commercial 3D electromagnetic simulator. The OMT consists of two mechanical blocks fabricated in split-block configuration using conventional CNC milling machine. From 84 to 116 GHz the measured input reflection coefficient was less than -17 dB, the isolation between the outputs was less than -50 dB, the cross polarization was less than -30 dB, and the transmission was larger than -0.35 dB at room temperature for both polarization channels. The device is suitable for scaling to higher frequency.

  12. Discontinuous dual-primal mixed finite elements for elliptic problems

    Science.gov (United States)

    Bottasso, Carlo L.; Micheletti, Stefano; Sacco, Riccardo

    2000-01-01

    We propose a novel discontinuous mixed finite element formulation for the solution of second-order elliptic problems. Fully discontinuous piecewise polynomial finite element spaces are used for the trial and test functions. The discontinuous nature of the test functions at the element interfaces allows to introduce new boundary unknowns that, on the one hand enforce the weak continuity of the trial functions, and on the other avoid the need to define a priori algorithmic fluxes as in standard discontinuous Galerkin methods. Static condensation is performed at the element level, leading to a solution procedure based on the sole interface unknowns. The resulting family of discontinuous dual-primal mixed finite element methods is presented in the one and two-dimensional cases. In the one-dimensional case, we show the equivalence of the method with implicit Runge-Kutta schemes of the collocation type exhibiting optimal behavior. Numerical experiments in one and two dimensions demonstrate the order accuracy of the new method, confirming the results of the analysis.

  13. Dual Ion Beam Deposition Of Diamond Films On Optical Elements

    Science.gov (United States)

    Deutchman, Arnold H.; Partyka, Robert J.; Lewis, J. C.

    1990-01-01

    Diamond film deposition processes are of great interest because of their potential use for the formation of both protective as well as anti-reflective coatings on the surfaces of optical elements. Conventional plasma-assisted chemical vapor deposition diamond coating processes are not ideal for use on optical components because of the high processing temperatures required, and difficulties faced in nucleating films on most optical substrate materials. A unique dual ion beam deposition technique has been developed which now makes possible deposition of diamond films on a wide variety of optical elements. The new DIOND process operates at temperatures below 150 aegrees Farenheit, and has been used to nucleate and grow both diamondlike carbon and diamond films on a wide variety of optical :taterials including borosilicate glass, quartz glass, plastic, ZnS, ZnSe, Si, and Ge.

  14. The Prediction of Transducer Element Performance from In-Air Measurements.

    Science.gov (United States)

    1982-01-19

    33 13. Predicted and Measured Transducer Impedance . . . 35 14. Principle of Operation of Fotonic Sensor . . . . 40 15. Experimental Set-up for...TARGET D ISPLACEMENT Figure 14. Principle of operation of Fotonic sensor 41 operation of the light fiber probe. As a test surface moves away from the

  15. An Ikaros Promoter Element with Dual Epigenetic and Transcriptional Activities.

    Science.gov (United States)

    Perotti, Elizabeth A; Georgopoulos, Katia; Yoshida, Toshimi

    2015-01-01

    Ikaros DNA binding factor plays critical roles in lymphocyte development. Changes in Ikaros expression levels during lymphopoiesis are controlled by redundant but also unique regulatory elements of its locus that are critical for this developmental process. We have recently shown that Ikaros binds its own locus in thymocytes in vivo. Here, we evaluated the role of an Ikaros binding site within its major lympho-myeloid promoter. We identified an Ikaros/Ets binding site within a promoter sub-region that was highly conserved in mouse and human. Deletion of this binding site increased the percentage of the reporter-expressing mouse lines, indicating that its loss provided a more permissive chromatin environment. However, once transcription was established, the lack of this site decreased transcriptional activity. These findings implicate a dual role for Ikaros/Ets1 binding on Ikzf1 expression that is exerted at least through its promoter.

  16. An Ikaros Promoter Element with Dual Epigenetic and Transcriptional Activities.

    Directory of Open Access Journals (Sweden)

    Elizabeth A Perotti

    Full Text Available Ikaros DNA binding factor plays critical roles in lymphocyte development. Changes in Ikaros expression levels during lymphopoiesis are controlled by redundant but also unique regulatory elements of its locus that are critical for this developmental process. We have recently shown that Ikaros binds its own locus in thymocytes in vivo. Here, we evaluated the role of an Ikaros binding site within its major lympho-myeloid promoter. We identified an Ikaros/Ets binding site within a promoter sub-region that was highly conserved in mouse and human. Deletion of this binding site increased the percentage of the reporter-expressing mouse lines, indicating that its loss provided a more permissive chromatin environment. However, once transcription was established, the lack of this site decreased transcriptional activity. These findings implicate a dual role for Ikaros/Ets1 binding on Ikzf1 expression that is exerted at least through its promoter.

  17. Dual-Use Transducer for Use with a Boundary-Stiffened Panel and Method of Using the Same

    Science.gov (United States)

    Schiller, Noah H. (Inventor); Cabell, Randolph H. (Inventor)

    2011-01-01

    A transducer for use with a boundary-stiffened panel has an inter-digitated electrode (IDE) and a piezoelectric wafer portion positioned therebetween. The IDE and/or the wafer portion are triangular, with one edge or side aligned with a boundary edge of the panel. The transducer generates and transmits an output force to the panel in response to an input voltage signal from a sensor, which can be another transducer as described above or an accelerometer. A controller can generate an output force signal in response to the input voltage signal to help cancel the input voltage signal. A method of using the transducer minimizes vibration in the panel by connecting multiple transducers around a perimeter thereof. Motion is measured at different portions of the panel, and a voltage signal determined from the motion is transmitted to the transducers to generate an output force at least partially cancelling or damping the motion.

  18. 20/30 GHz dual-band circularly polarized reflectarray antenna based on the concentric dual split-loop element

    DEFF Research Database (Denmark)

    Smith, Thomas Gunst; Vesterdal Larsen, Niels; Vesterager Gothelf, Ulrich

    2012-01-01

    A concentric dual split-loop element is designed and investigated for reflectarray antenna design in the emerging 20 GHz and 30 GHz Ka-band satellite communication spectrum. The element is capable of providing adjustment of the phase of reflection coefficients for circular plane waves in two...

  19. Growth stimulation of Bacillus cereus and Pseudomonas putida using nanostructured ZnO thin film as transducer element

    Energy Technology Data Exchange (ETDEWEB)

    Loukanov, Alexandre, E-mail: loukanov@mail.saitama-u.ac.jp [Saitama University, Department of Chemistry, Faculty of Science (Japan); Filipov, Chavdar [University of Forestry, Department of Infectious pathology, hygiene, technology and control of food stuffs of animal origin, Faculty of Veterinary Medicine (Bulgaria); Valcheva, Violeta [Bulgarian Academy of Science, Department of Infectious Diseases, Institute of microbiology (Bulgaria); Lecheva, Marta [University of Mining and Geology “St. Ivan Rilski”, Laboratory of Engineering NanoBiotechnology, Department of Engineering Geoecology (Bulgaria); Emin, Saim [University of Nova Gorica, Materials Research Laboratory (Slovenia)

    2015-04-15

    The semiconductor zinc oxide nanomaterial (ZnO or ZnO:H) is widely used in advanced biosensor technology for the design of highly-sensitive detector elements for various applications. In the attempt to evaluate its effect on common microorganisms, two types of nanostructured transducer films have been used (average diameter 600–1000 nm). They have been prepared by using both wet sol–gel method and magnetron sputtering. Their polycrystalline structure and specific surface features have been analyzed by X-ray diffraction (XRD), scanning electron microscope, and atomic force microscope. The assessment of growth stimulation of bacteria was determined using epifluorescent microscope by cell staining with Live/Dead BacLight kit. In our experiments, the growth stimulation of Gram-positive and Gram-negative bacteria on nanostructured ZnO film is demonstrated by Bacillus cereus and Pseudomonas putida. These two bacterial species have been selected, because they are well known and studied in biosensor technologies, with structural difference of their cell walls. These pathogens are easy for with common source in the liquid food or some commercial products. Our data has revealed that the method of transducer film preparation influences strongly bacterial inhibition and division. These results present the transforming signal precisely, when ZnO is used in biosensor applications.

  20. First IDA Submittal for Transducer Element Design for Loosely Packed Planar Array Common Problem 1.1

    Science.gov (United States)

    1966-05-11

    FIRST IDA SUBMITTAL FOR TRANSDUCER ELEMENT DESIGN FOR LOOSELY PACKED PLANAR ARRAY CID COMMON PROBLEM 1. 1 Submitted to Conformal/Planar Array Project...R4JEN2’ TRACOR, INC. MID BAND 6..I ~JUUliL-UnLU i C.P. 1 5 INCH CIRCULRR HERD MIO BRINO LPz.3777 QP=E +iD L1oooo -i00 F -WFC 4q(TI’ ERT R-EC c-AE O ALPPE...8217 LcO [a x I. Cr l Z2) D zS x) q." L)I I Iu T~ xj Co4 C3= 1-L Z (nw x V O vV 5% C3 CD .* * -3x U l 1C .) uw wU -A CID .4 i I--I- U- 49 (1’)W uri J m LAJ 0

  1. APPLICATION OF THE DUAL RECIPROCITY BOUNDARY ELEMENT METHOD TO SOLUTION OF NONLINEAR DIFFERENTIAL EQUATION

    Institute of Scientific and Technical Information of China (English)

    Long Shuyao; Zhang Qin

    2000-01-01

    In this paper the dual reciprocity boundary element method is employed to solve nonlinear differential equation 2 u + u + εu3 = b. Results obtained in an example have a good agreement with those by FEM and show the applicability and simplicity of dual reciprocity method(DRM) in solving nonlinear dif ferential equations.

  2. User Manual for ATILA, a Finite-Element Code for Modeling Piezoelectric Transducers.

    Science.gov (United States)

    1987-09-01

    STUPFEL, A. LAVIE, J.N. DECARPIGNY, "Implantation dlans le code ATILA du coupiage elements flnls et equations integrales ", G.E.R.D.S.M., Convention C...In a large part , automatically obtained, as explained In chapter 6. A detailed check of the data file can be processed by running a specific progam...page displays a simple flow chart of an ATILA finite element modelling. A large part of this flow chart will be reproduced In a more detailed and

  3. Synthetic Aperture Focusing Applied to Imaging Using a Rotating Single Element Transducer

    DEFF Research Database (Denmark)

    Kortbek, Jacob; Jensen, Jørgen Arendt; Gammelmark, Kim Løkke

    2007-01-01

    This paper applies the concept of virtual sources and mono-static synthetic aperture focusing (SAF) to 2-dimensional imaging with a single rotating mechanically focused concave element with the objective of improving lateral resolution and signal-to-noise ratio (SNR). The geometrical focal point ...

  4. Application of the dual reciprocity boundary element method for numerical modelling of solidification process

    Directory of Open Access Journals (Sweden)

    E. Majchrzak

    2008-12-01

    Full Text Available The dual reciprocity boundary element method is applied for numerical modelling of solidification process. This variant of the BEM is connected with the transformation of the domain integral to the boundary integrals. In the paper the details of the dual reciprocity boundary element method are presented and the usefulness of this approach to solidification process modelling is demonstrated. In the final part of the paper the examples of computations are shown.

  5. 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

  6. 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

  7. Elements of dual scaling an introduction to practical data analysis

    CERN Document Server

    Nishisato, Shizuhiko

    2014-01-01

    Quantification methodology of categorical data is a popular topic in many branches of science. Most books, however, are either too advanced for those who need it, or too elementary to gain insight into its potential. This book fills the gap between these extremes, and provides specialists with an easy and comprehensive reference, and others with a complete treatment of dual scaling methodology -- starting with motivating examples, followed by an introductory discussion of necessary quantitative skills, and ending with different perpsectives on dual scaling with examples, advanced topics, and f

  8. Sensitive elements of pressure transducers made of layered intercalated InSe, GaSe, and Bi2Te3 crystals

    Science.gov (United States)

    Kudrynskyi, Z. R.; Kovalyuk, Z. D.

    2013-12-01

    It is shown that layered InSe, GaSe, and Bi2Te3 semiconductors are promising for sensitive elements of pressure transducers. Two ways for measuring pressure with layered crystals are suggested: from the pressure dependence of the intercalation parameter (current) and from the pressure dependence of the intercalate electromotive force.

  9. Piezoelectric Composite Micromachined Multifrequency Transducers for High-Resolution, High-Contrast Ultrasound Imaging for Improved Prostate Cancer Assessment

    Science.gov (United States)

    2016-10-01

    MHz) transducer was developed for demonstrating the feasibility of transrectal acoustic angiography. This was the first dual mode 3/15 MHz array... acoustic angiography imaging in intracavity applications. A single element dual-frequency IVUS transducer was developed for concept validation, which...the backside of the transmitter is close to the free boundary, which cannot absorb backward travelling waves, the low acoustic impedance (19.8 MRayl

  10. Optimal Design of a 1-3 Piezocomposite Tonpilz Transducer by Means of the Finite Element Method

    Science.gov (United States)

    Pei, Da Lie; Roh, Yongrae

    Underwater Tonpilz transducer is designed with 1-3 piezocomposite materials to overcome the problems with conventional piezoceramic transducers. With the FEM, the variation of the resonance frequency, bandwidth and sound pressure of the transducer are analyzed in relation to the structural variables of the transducer. Through statistical multiple regression analysis of the results, functional forms of the transducer performance are derived in terms of design variables. By applying the constrained optimization technique, SQP-PD, to the derived functions, the optimal structure of the transducer is determined that can provide the highest sound pressure level at a given resonant frequency over a pre-determined frequency range. The validity of the optimized results is confirmed through comparison of the optimal performance with that of the FEA.

  11. Modeling of ultrasound transducers

    DEFF Research Database (Denmark)

    Bæk, David

    deviation of 5.5 % to 11.0 %. Finite element modeling of piezoceramics in combination with Field II is addressed and reveals the influence of restricting the modeling of transducers to the one-dimensional case. An investigation on modeling capacitive micromachined ultrasonic transducers (CMUT)s with Field......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...... II is addressed. It is shown how a single circular CMUT cell can be well approximated with a simple square transducer encapsulating the cell, and how this influence the modeling of full array elements. An optimal cell discretization with Field II’s mathematical elements is addressed as well...

  12. Circuit-field coupled finite element analysis method for an electromagnetic acoustic transducer under pulsed voltage excitation

    Institute of Scientific and Technical Information of China (English)

    Hao Kuan-Sheng; Huang Song-Ling; Zhao Wei; Wang Shen

    2011-01-01

    This paper presents an analytical method for electromagnetic acoustic transducers (EMATs) under voltage excitation and considers the non-uniform distribution of the biased magnetic field. A complete model of EMATs including the non-uniform biased magnetic field, a pulsed eddy current field and the acoustic field is built up. The pulsed voltage excitation is transformed to the frequency domain by fast Fourier transformation (FFT). In terms of the time harmonic field equations of the EMAT system, the impedances of the coils under different frequencies are calculated according to the circuit-field coupling method and Poynting's theorem. Then the currents under different frequencies are calculated according to Ohm's law and the pulsed current excitation is obtained by inverse fast Fourier transformation (IFFT).Lastly, the sequentially coupled finite element method (FEM) is used to calculate the Lorentz force in the EMATs under the current excitation. An actual EMAT with a two-layer two-bundle printed circuit board (PCB) coil, a rectangular permanent magnet and an aluminium specimen is analysed. The coil impedances and the pulsed current are calculated and compared with the experimental results. Their agreement verified the validity of the proposed method. Furthermore, the influences of lift-off distances and the non-uniform static nagnetic field on the Lorentz force under pulsed voltage excitation are studied.

  13. A Dual Orthogonality Procedure for Nonlinear Finite Element Equations

    DEFF Research Database (Denmark)

    Krenk, S.; Hededal, O.

    In the orthogonal residual procedure for solution of nonlinear finite element equations the load is adjusted in each equilibrium iteration to satisfy an orthogonality condition to the current displacement increment. It is here shown that the quasi-newton formulation of the orthogonal residual...

  14. Studies of the source complex behaviour and of the ultrasound radiation of contact flexible multi-element transducers; Etudes du comportement complexe de source et du rayonnement ultrasonore des traducteurs multi-elements flexibles au contact

    Energy Technology Data Exchange (ETDEWEB)

    Amory, V

    2007-12-15

    This work deals with the ultrasonic nondestructive testing of parts with complex geometries using soft multi-element sensors. The different types of contact control configurations are presented first. Then, the difficulties encountered with conventional contact transducers are explained and the multi-element piezoelectric transducers technology, developed to meet these difficulties, is presented. The second chapter presents the results of finite-element calculations showing the complexity of a transducer in a condition of testing utilization. In a same configuration, the radiated far field calculated by finite-elements is compared to the measurement in order to validate the way the source behaviour is calculated. However, despite the efficiency of the finite-elements simulation, this tool is numerically too costly and cannot be used to optimize a full multi-element transducer. Therefore, a realistic source model is built and implemented in a radiation code based on high-frequency asymptotic approximations where only L and T volume waves are calculated. The incapacity of this model to reproduce the behaviour of T waves in some directions of propagation has led to give a particular attention to the fore-waves, neglected in the radiation calculation. Chapter 3 treats of the building of an exact radiation model taking into consideration the fore-waves contribution emitted by a contact transducer exerting a random space-time distribution constraint at the surface of the considered medium. A radiation model, based on the calculation of exact Green functions of the Lamb problem is proposed. The exact model is particularly interesting in the case of sensor geometries with a long length with respect to other dimensions (2D case). Field calculation results are shown for an element of the matrix network (3D case) and for a linear element (2D case). A study of different existing approached models is carried out as well. The last chapter presents some results of the field

  15. 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.

  16. Study of an athermal infrared dual band optical system design containing harmonic diffractive element

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A harmonic diffractive element (HDE) is first successfully introduced to the athermal system of infrared dual band in this paper. In this system, there are only three lens and two materials, silicon and germanium. When the temperature ranges from -70℃ to 100℃ in the dual band, it can simultaneously accomplish the rectification of the longitudinal aberration in the big field of view, as well as the wave front aberration less than 1/4 wavelength. Modulation transfer function of dual band approaches or attains the diffraction limit. The calculation results show that the spectral properties of the HDE are between refractive and diffractive elements, so we can design a simple dual-band and athermal optical system by selecting the thickness and central wavelength of the HDE exactly. Compared with a conventional refractive optical system, this system not only reduces the demand for high technical levels, but also has a compact structure, few elements, a high transmittance better aberrations performances and athermal character. At the same time, the use of the HDE also offers a new element for the infrared optics design.

  17. 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.

  18. Imaging and elemental mapping of biological specimens with a dual-EDS dedicated scanning transmission electron microscope

    Science.gov (United States)

    Wu, J.S.; Kim, A. M.; Bleher, R.; Myers, B.D.; Marvin, R. G.; Inada, H.; Nakamura, K.; Zhang, X.F.; Roth, E.; Li, S.Y.; Woodruff, T. K.; O'Halloran, T. V.; Dravid, Vinayak P.

    2013-01-01

    A dedicated analytical scanning transmission electron microscope (STEM) with dual energy dispersive spectroscopy (EDS) detectors has been designed for complementary high performance imaging as well as high sensitivity elemental analysis and mapping of biological structures. The performance of this new design, based on a Hitachi HD-2300A model, was evaluated using a variety of biological specimens. With three imaging detectors, both the surface and internal structure of cells can be examined simultaneously. The whole-cell elemental mapping, especially of heavier metal species that have low cross-section for electron energy loss spectroscopy (EELS), can be faithfully obtained. Optimization of STEM imaging conditions is applied to thick sections as well as thin sections of biological cells under low-dose conditions at room- and cryogenic temperatures. Such multimodal capabilities applied to soft/biological structures usher a new era for analytical studies in biological systems. PMID:23500508

  19. DUAL RECIPROCITY BOUNDARY ELEMENT METHOD FOR FLEXURAL WAVES IN THIN PLATE WITH CUTOUT

    Institute of Scientific and Technical Information of China (English)

    GAO Suo-wen; WANG Yue-sheng; ZHANG Zi-mao; MA Xing-rui

    2005-01-01

    The theoretical analysis and numerical calculation of scattering of elastic waves and dynamic stress concentrations in the thin plate with the cutout was studied using dual reciprocity boundary element method (DRM). Based on the work equivalent law, the dual reciprocity boundary integral equations for flexural waves in the thin plate were established using static fundamental solution. As illustration, numerical results for the dynamic stress concentration factors in the thin plate with a circular hole are given.The results obtained demonstrate good agreement with other reported results and show high accuracy.

  20. Dual doped monolayer and bilayer graphene: The case of 4p and 2p elements

    Science.gov (United States)

    Denis, Pablo A.; Iribarne, Federico

    2016-08-01

    4p/2p dual-doped monolayer and bilayer graphene were studied via first principle calculations. Generally, dopants prefer to be agglomerated. A second dopant significantly reduces formation energies. Thus, partially reduced graphene oxide would favor substitutional doping by facilitating the introduction of the 4p dopants. Dual-doping can tune the band gap from 0.1 to 0.8 eV. For bilayer graphene, large atomic radii elements (Gallium and Germanium) form interlayer bonds with the undoped sheet. For some dual-doped graphenes, interlayer GaC and GeC bonds were formed, increasing the chemical reactivity of the undoped layer and affecting its electronic structure, with metallic or semiconducting characters observed.

  1. An IVUS Transducer for Microbubble Therapies

    Science.gov (United States)

    Kilroy, Joseph P.; Patil, Abhay V.; Rychak, Joshua J.; Hossack, John A.

    2014-01-01

    There is interest in examining the potential of modified intravascular ultrasound (IVUS) catheters to facilitate dual diagnostic and therapeutic roles using ultrasound plus microbubbles for localized drug delivery to the vessel wall. The goal of this study was to design, prototype, and validate an IVUS transducer for microbubble-based drug delivery. A 1-D acoustic radiation force model and finite element analysis guided the design of a 1.5-MHz IVUS transducer. Using the IVUS transducer, biotinylated microbubbles were displaced in water and bovine whole blood to the streptavidin-coated wall of a flow phantom by a 1.5-MHz center frequency, peak negative pressure = 70 kPa pulse with varying pulse repetition frequency (PRF) while monitoring microbubble adhesion with ultrasound. A fit was applied to the RF data to extract a time constant (τ). As PRF was increased in water, the time constant decreased (τ = 32.6 s, 1 kHz vs. τ = 8.2 s, 6 kHz), whereas in bovine whole blood an adhesion–no adhesion transition was found for PRFs ≥ 8 kHz. Finally, a fluorophore was delivered to an ex vivo swine artery using microbubbles and the IVUS transducer, resulting in a 6.6-fold increase in fluorescence. These results indicate the importance of PRF (or duty factor) for IVUS acoustic radiation force microbubble displacement and the potential for IVUS and microbubbles to provide localized drug delivery. PMID:24569249

  2. Microinterferometer transducer

    Science.gov (United States)

    Corey, III, Harry S.

    1979-01-01

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

  3. Quantification of colloidal and aqueous element transfer in soils: The dual-phase mass balance model

    Science.gov (United States)

    Bern, Carleton R.; Thompson, Aaron; Chadwick, Oliver A.

    2015-01-01

    Mass balance models have become standard tools for characterizing element gains and losses and volumetric change during weathering and soil development. However, they rely on the assumption of complete immobility for an index element such as Ti or Zr. Here we describe a dual-phase mass balance model that eliminates the need for an assumption of immobility and in the process quantifies the contribution of aqueous versus colloidal element transfer. In the model, the high field strength elements Ti and Zr are assumed to be mobile only as suspended solids (colloids) and can therefore be used to distinguish elemental redistribution via colloids from redistribution via dissolved aqueous solutes. Calculations are based upon element concentrations in soil, parent material, and colloids dispersed from soil in the laboratory. We illustrate the utility of this model using a catena in South Africa. Traditional mass balance models systematically distort elemental gains and losses and changes in soil volume in this catena due to significant redistribution of Zr-bearing colloids. Applying the dual-phase model accounts for this colloidal redistribution and we find that the process accounts for a substantial portion of the major element (e.g., Al, Fe and Si) loss from eluvial soil. In addition, we find that in illuvial soils along this catena, gains of colloidal material significantly offset aqueous elemental loss. In other settings, processes such as accumulation of exogenous dust can mimic the geochemical effects of colloid redistribution and we suggest strategies for distinguishing between the two. The movement of clays and colloidal material is a major process in weathering and pedogenesis; the mass balance model presented here is a tool for quantifying effects of that process over time scales of soil development.

  4. Real-time monitoring of focused ultrasound blood-brain barrier opening via subharmonic acoustic emission detection: implementation of confocal dual-frequency piezoelectric transducers

    Science.gov (United States)

    Tsai, Chih-Hung; Zhang, Jia-Wei; Liao, Yi-Yi; Liu, Hao-Li

    2016-04-01

    Burst-tone focused ultrasound exposure in the presence of microbubbles has been demonstrated to be effective at inducing temporal and local opening of the blood-brain barrier (BBB), which promises significant clinical potential to deliver therapeutic molecules into the central nervous system (CNS). Traditional contrast-enhanced imaging confirmation after focused ultrasound (FUS) exposure serves as a post-operative indicator of the effectiveness of FUS-BBB opening, however, an indicator that can concurrently report the BBB status and BBB-opening effectiveness is required to provide effective feedback to implement this treatment clinically. In this study, we demonstrate the use of subharmonic acoustic emission detection with implementation on a confocal dual-frequency piezoelectric ceramic structure to perform real-time monitoring of FUS-BBB opening. A confocal dual-frequency (0.55 MHz/1.1 MHz) focused ultrasound transducer was designed. The 1.1 MHz spherically-curved ceramic was employed to deliver FUS exposure to induce BBB-opening, whereas the outer-ring 0.55 MHz ceramic was employed to detect the subharmonic acoustic emissions originating from the target position. In stage-1 experiments, we employed spectral analysis and performed an energy spectrum density (ESD) calculation. An optimized 0.55 MHz ESD level change was shown to effectively discriminate the occurrence of BBB-opening. Wideband acoustic emissions received from 0.55 MHz ceramics were also analyzed to evaluate its correlations with erythrocyte extravasations. In stage-2 real-time monitoring experiments, we applied the predetermined ESD change as a detection threshold in PC-controlled algorithm to predict the FUS exposure intra-operatively. In stage-1 experiment, we showed that subharmonic ESD presents distinguishable dynamics between intact BBB and opened BBB, and therefore a threshold ESD change level (5.5 dB) can be identified for BBB-opening prediction. Using this ESD change threshold detection as a

  5. Real-time monitoring of focused ultrasound blood-brain barrier opening via subharmonic acoustic emission detection: implementation of confocal dual-frequency piezoelectric transducers.

    Science.gov (United States)

    Tsai, Chih-Hung; Zhang, Jia-Wei; Liao, Yi-Yi; Liu, Hao-Li

    2016-04-07

    Burst-tone focused ultrasound exposure in the presence of microbubbles has been demonstrated to be effective at inducing temporal and local opening of the blood-brain barrier (BBB), which promises significant clinical potential to deliver therapeutic molecules into the central nervous system (CNS). Traditional contrast-enhanced imaging confirmation after focused ultrasound (FUS) exposure serves as a post-operative indicator of the effectiveness of FUS-BBB opening, however, an indicator that can concurrently report the BBB status and BBB-opening effectiveness is required to provide effective feedback to implement this treatment clinically. In this study, we demonstrate the use of subharmonic acoustic emission detection with implementation on a confocal dual-frequency piezoelectric ceramic structure to perform real-time monitoring of FUS-BBB opening. A confocal dual-frequency (0.55 MHz/1.1 MHz) focused ultrasound transducer was designed. The 1.1 MHz spherically-curved ceramic was employed to deliver FUS exposure to induce BBB-opening, whereas the outer-ring 0.55 MHz ceramic was employed to detect the subharmonic acoustic emissions originating from the target position. In stage-1 experiments, we employed spectral analysis and performed an energy spectrum density (ESD) calculation. An optimized 0.55 MHz ESD level change was shown to effectively discriminate the occurrence of BBB-opening. Wideband acoustic emissions received from 0.55 MHz ceramics were also analyzed to evaluate its correlations with erythrocyte extravasations. In stage-2 real-time monitoring experiments, we applied the predetermined ESD change as a detection threshold in PC-controlled algorithm to predict the FUS exposure intra-operatively. In stage-1 experiment, we showed that subharmonic ESD presents distinguishable dynamics between intact BBB and opened BBB, and therefore a threshold ESD change level (5.5 dB) can be identified for BBB-opening prediction. Using this ESD change threshold detection as a

  6. 稀土Tonpilz换能器的有限元设计法%The finite element method for designing rare earth Tonpilz transducer

    Institute of Scientific and Technical Information of China (English)

    贺西平; 李斌; 孙进才

    2001-01-01

    When large difference in the cross sectional areas occur between components of Tonpilz transducer, the stress or the strain will not be continuous at the junctions.The assumption of continuous boundary conditions will not hold in situations, like the designing by the use of the four terminal networks be continuously as well. In this paper,a rare earth giant magnetostrictive Tonpilz transducer is designed and manufactured by means of the finite element method. It is shown through experimental measurement that the design precision of the finite element method is better than that of the four-terminal networks design method.%当Tonpilz换能器组件中横截面面积之间相差较大时,应力、应变会有一定的突变,边界条件将不很连续,用四端网络方法设计会带来较大的误差.本文用有限元方法,设计并研制了一稀土Tonpilz型换能器.实验测试表明,与四端网络设计法相比,有限元方法具有更好的设计精度.

  7. 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....

  8. MINOS: a nodal method; approximation by mixed dual finite elements in the Cronos code; La methode nodale de Cronos: MINOS, approximation par des elements mixtes duaux

    Energy Technology Data Exchange (ETDEWEB)

    Lautard, J.J.

    1994-05-01

    This paper presents new extension for the mixed dual finite element approximation of the diffusion equation in rectangular geometry. The mixed dual formulation has been extended in order to take into account discontinuity conditions. The iterative method is based on an alternating direction method which uses the current as unknown. This method is fully ``parallelizable`` and has very quick convergence properties. Some results for a 3D calculation on the CRAY computer are presented. (author). 6 refs., 8 figs., 4 tabs.

  9. Ultrasonic transducer

    Science.gov (United States)

    Taylor, Steven C.; Kraft, Nancy C.

    2007-03-13

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

  10. Dual Band Parasitic Element Patch Antenna for LTE/WLAN Applications

    Directory of Open Access Journals (Sweden)

    BAG Biplab

    2017-05-01

    Full Text Available In this paper, a single layer coaxial fed dual band slotted microstrip antenna is proposed. The proposed antenna consists of two direct couple parasitic elements and L-shape slots on the main resonating element. Two resonant modes are excited and it covers 4G LTE and WLAN middle band. The -10dB impedance bandwidth for resonant frequency of 2.35GHz and 5.28GHz are 140MHz (2.25-2.39GHz and 570MHz (5.18-5.75GHz, respectively. The measured VSWR at 2.35GHz is 1.27 and at 5.28GHz is 1.41. The proposed antenna is simple in design and compact in size. The simulated and measured results are in good agreement.

  11. Acoustic transducer with damping means

    Science.gov (United States)

    Smith, Richard W.; Adamson, Gerald E.

    1976-11-02

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

  12. Focused ultrasound transducer for thermal treatment.

    Science.gov (United States)

    Umemura, Shin-ichiro

    2015-03-01

    Air-backed transducers have been employed for thermal ultrasonic treatment including both ablation and hyperthermia because the power efficiency rather than the bandwidth is a main concern, unlike a typical imaging transducer working in a pulse mode. The characteristic of an air-backed piezoelectric transducer with a matching layer is analysed, and the role and choice of the matching layer is discussed. An element size of a focused array transducer, appropriate for such thermal treatment, is then estimated, and the characteristic of a piezoceramic transducer element of such a size was numerically analysed using a finite element code. The characteristic of a piezocomposite transducer element is also numerically analysed and its suitability to such a therapeutic array transducer is discussed.

  13. Rare earth elements recycling from waste phosphor by dual hydrochloric acid dissolution.

    Science.gov (United States)

    Liu, Hu; Zhang, Shengen; Pan, Dean; Tian, Jianjun; Yang, Min; Wu, Maolin; Volinsky, Alex A

    2014-05-15

    This paper is a comparative study of recycling rare earth elements from waste phosphor, which focuses on the leaching rate and the technical principle. The traditional and dual dissolution by hydrochloric acid (DHA) methods were compared. The method of dual dissolution by hydrochloric acid has been developed. The Red rare earth phosphor (Y0.95Eu0.05)2O3 in waste phosphor is dissolved during the first step of acid leaching, while the Green phosphor (Ce0.67Tb0.33MgAl11O19) and the Blue phosphor (Ba0.9Eu0.1MgAl10O17) mixed with caustic soda are obtained by alkali sintering. The excess caustic soda and NaAlO2 are removed by washing. The insoluble matter is leached by the hydrochloric acid, followed by solvent extraction and precipitation (the DHA method). In comparison, the total leaching rate of the rare earth elements was 94.6% by DHA, which is much higher than 42.08% achieved by the traditional method. The leaching rate of Y, Eu, Ce and Tb reached 94.6%, 99.05%, 71.45%, and 76.22%, respectively. DHA can decrease the consumption of chemicals and energy. The suggested DHA method is feasible for industrial applications.

  14. 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.

  15. Miniature multimode monolithic flextensional transducers.

    Science.gov (United States)

    Hladky-Hennion, Anne-Christine; Uzgur, A Erman; Markley, Douglas C; Safari, Ahmad; Cochran, Joe K; Newnham, Robert E

    2007-10-01

    Traditional flextensional transducers classified in seven groups based on their designs have been used extensively in 1-100 kHz range for mine hunting, fish finding, oil explorations, and biomedical applications. In this study, a new family of small, low cost underwater, and biomedical transducers has been developed. After the fabrication of transducers, finite-elements analysis (FEA) was used extensively in order to optimize these miniature versions of high-power, low-frequency flextensional transducer designs to achieve broad bandwidth for both transmitting and receiving, engineered vibration modes, and optimized acoustic directivity patterns. Transducer topologies with various shapes, cross sections, and symmetries can be fabricated through high-volume, low-cost ceramic and metal extrusion processes. Miniaturized transducers posses resonance frequencies in the range of above 1 MHz to below 10 kHz. Symmetry and design of the transducer, polling patterns, driving and receiving electrode geometries, and driving conditions have a strong effect on the vibration modes, resonance frequencies, and radiation patterns. This paper is devoted to small, multimode flextensional transducers with active shells, which combine the advantages of small size and low-cost manufacturing with control of the shape of the acoustic radiation/receive pattern. The performance of the transducers is emphasized.

  16. Pressure transducer

    Science.gov (United States)

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

    1989-01-01

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

  17. A Compact Dual Band Implantable Antenna Based on Split-Ring Resonators with Meander Line Elements

    Directory of Open Access Journals (Sweden)

    Yunus Emre Yamac

    2016-12-01

    Full Text Available In this paper, a dual band implantable split-ring microstrip antenna which operates at MICS (Medical Implant Services and ISM (Industrial, Scientific, and Medical bands is proposed for biotelemetry applications. A miniaturized size of 9.5 mm × 9.5 mm × 1.27 mm was accomplished by using three split-ring resonators and meander lines elements on these resonators. A shorting pin appropriately placed between the patch and ground plane was used for the antenna miniaturization. In addition, three useful metallic paths between the rings provided fine frequency tuning. The proposed split-ring implantable antenna presents 23.5% and 9.3% bandwidth, -48 dB and -24 dB maximum gains, 407 W/kg and 403 W/kg maximum 1-g averaged SAR values at the respective bands. Return loss performance, radiation patterns and SAR values of the antenna design are presented in the paper.

  18. Element Specific Observation of Ferromagnetic Interlayer Exchange Coupled Dual Vortex Core Nano Systems

    Science.gov (United States)

    Pulecio, Javier; Arena, Dario; Warnicke, Peter; Im, Mi-Young; Pollard, Shawn; Fischer, Peter; Zhu, Yimei

    2013-03-01

    We report on the magnetic evolution of magnetic vortices in nanoscale and multilayer disk structures. The tri-layer structure consists of Co and Permalloy (Py) layers, coupled across a thin (1nm) Cu spacer that provides strong coupling between the Co and Py layers. Element-resolved full-field XMCD microscopy is combined with ultra-high resolution Lorentz transmission electron microscopy, permitting measurement of both layer-resolved domain patterns and the vortex structure averaged across the tri-layer. We examine the evolution of the vortex structure while the nanostructure is cycled through the M-H hysteresis loop. In particular we will discuss the effects of strong interlayer exchanged coupling on a dual vortex core system, including analysis of the layer-resolved coercivity, and the evolution, deformation, annihilation, and nucleation of the vortices.

  19. Polymer film composite transducer

    Science.gov (United States)

    Owen, Thomas E.

    2005-09-20

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

  20. Linearized primal-dual methods for linear inverse problems with total variation regularization and finite element discretization

    Science.gov (United States)

    Tian, Wenyi; Yuan, Xiaoming

    2016-11-01

    Linear inverse problems with total variation regularization can be reformulated as saddle-point problems; the primal and dual variables of such a saddle-point reformulation can be discretized in piecewise affine and constant finite element spaces, respectively. Thus, the well-developed primal-dual approach (a.k.a. the inexact Uzawa method) is conceptually applicable to such a regularized and discretized model. When the primal-dual approach is applied, the resulting subproblems may be highly nontrivial and it is necessary to discuss how to tackle them and thus make the primal-dual approach implementable. In this paper, we suggest linearizing the data-fidelity quadratic term of the hard subproblems so as to obtain easier ones. A linearized primal-dual method is thus proposed. Inspired by the fact that the linearized primal-dual method can be explained as an application of the proximal point algorithm, a relaxed version of the linearized primal-dual method, which can often accelerate the convergence numerically with the same order of computation, is also proposed. The global convergence and worst-case convergence rate measured by the iteration complexity are established for the new algorithms. Their efficiency is verified by some numerical results.

  1. Numerical solutions of multi-dimensional solidification/melting problems by the dual reciprocity boundary element method

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Jong Chull; Shin, Won Ky [Korea Institute of Nuclear Safety, Taejon (Korea, Republic of)

    1997-12-31

    This paper presents an effective and simple procedure for the simulation of the motion of the solid-liquid interfacial boundary and the transient temperature field during phase change process. To accomplish this purpose, an iterative implicit solution algorithm has been developed by employing the dual reciprocity boundary element method. The dual reciprocity boundary element approach provided in this paper is much simpler than the usual boundary element method applying a reciprocity principle and an available technique for dealing with domain integral of boundary element formulation simultaneously. The effectiveness of the present analysis method have been illustrated through comparisons of the calculation results of an example with its semi-analytical or other numerical solutions where available. 22 refs., 3 figs. (Author)

  2. Shear bond strength of three dual-cured resin cements to dentin analyzed by finite element analysis

    NARCIS (Netherlands)

    Jongsma, L.A.; de Jager, N.; Kleverlaan, C.J.; Pallav, P.; Feilzer, A.J.

    2012-01-01

    Objectives To determine the shear bond strength to bovine dentin of dual-cured resin cements cured in different circumstances, the contraction stress and volumetric shrinkage in both polymerization modes, and to review the failure stress distribution at the cement-tooth interface with finite element

  3. 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....... However, there are several difficulties to be addressed that are derived from the size, internal structure and precision requirements that are characteristic of these devices. One of them, the presence of very close surfaces (e.g. the microphone diaphragm and back-electrode), leads to machine precision...

  4. 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...

  5. 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.

  6. Three dimensional transducer

    Science.gov (United States)

    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.

  7. 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.

  8. Operational experience and evaluation of a dual-element stretched-membrane heliostat

    Science.gov (United States)

    Strachan, J. W.; Vander, Geest, J.

    1994-01-01

    A dual-element, stretched-membrane central receiver heliostat was designed and manufactured in 1989 by a private US company engaged in the development of commercial central receiver solar technology. The two-module collector, with a collection area of 97.5 sq m, extends stretched-membrane mirror technology on several fronts with face-down stow capability and a digital controller that integrates tracking and focusing control on a single programmable control board. The solar collector was installed at Sandia's National Solar Thermal Test Facility in Albuquerque, NM, and it was evaluated over a three-and-a-half year period which ended in Sep. 1993. The measured performance and the operational and maintenance characteristics of this commercial prototype are the subject of this report. The results of beam quality measurements, tracking repeatability tests, measurements of beam movement in elevated winds, performance tests of the focusing system, and all-day beam quality and tracking tests are presented, and the authors offer a detailed discussion of the knowledge gained through operation and maintenance and of the improvements made or suggested to the heliostat's design.

  9. Modeling the Interaction Between Hydraulic and Natural Fractures Using Dual-Lattice Discrete Element Method

    Energy Technology Data Exchange (ETDEWEB)

    Zhou, Jing [Universiyt of Utah; Huang, Hai [Idaho National Lab. (INL), Idaho Falls, ID (United States); Deo, Milind

    2015-10-01

    The interaction between hydraulic fractures (HF) and natural fractures (NF) will lead to complex fracture networks due to the branching and merging of natural and hydraulic fractures in unconventional reservoirs. In this paper, a newly developed hydraulic fracturing simulator based on discrete element method is used to predict the generation of complex fracture network in the presence of pre-existing natural fractures. By coupling geomechanics and reservoir flow within a dual lattice system, this simulator can effectively capture the poro-elastic effects and fluid leakoff into the formation. When HFs are intercepting single or multiple NFs, complex mechanisms such as direct crossing, arresting, dilating and branching can be simulated. Based on the model, the effects of injected fluid rate and viscosity, the orientation and permeability of NFs and stress anisotropy on the HF-NF interaction process are investigated. Combined impacts from multiple parameters are also examined in the paper. The numerical results show that large values of stress anisotropy, intercepting angle, injection rate and viscosity will impede the opening of NFs.

  10. Operational experience and evaluation of a dual-element stretched-membrane heliostat

    Energy Technology Data Exchange (ETDEWEB)

    Strachan, J.W.; Van Der Geest, J.

    1994-01-01

    A dual-element, stretched-membrane central receiver heliostat was designed and manufactured in 1989, by a private US company engaged in the development of commercial central receiver solar technology. The two-module collector, with a collection area of 97.5 m{sup 2}, extends stretched-membrane mirror technology on several fronts with face-down stow capability and a digital controller that integrates tracking and focusing control on a single programmable control board. The solar collector was installed at Sandia`s National Solar Thermal Test Facility in Albuquerque, New Mexico and evaluated over a three-and-a-half year period which ended in September 1993. The measured performance and the operational and maintenance characteristics of this commercial prototype are the subject of this report. The results of beam quality measurements, tracking repeatability tests, measurements of beam movement in elevated winds, performance tests of the focusing system, and all-day beam quality and tracking tests are presented, and the authors offer a detailed discussion of the knowledge gained through operation and maintenance and of the improvements made or suggested to the heliostat`s design.

  11. 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

  12. 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.

  13. Micromachined Ultrasonic Transducers for 3-D Imaging

    DEFF Research Database (Denmark)

    Christiansen, Thomas Lehrmann

    such transducer arrays, capacitive micromachined ultrasonic transducer (CMUT) technology is chosen for this project. Properties such as high bandwidth and high design flexibility makes this an attractive transducer technology, which is under continuous development in the research community. A theoretical...... 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......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...

  14. 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

  15. Strategies for redundancy resolution of dual-arm systems with passive elements for tank waste removal

    Energy Technology Data Exchange (ETDEWEB)

    Dubey, R. [Univ. of Tennessee, Knoxville, TN (United States). Dept. of Mechanical Engineering; Love, L.J. [Oak Ridge Inst. for Science and Education, TN (United States)

    1997-03-01

    The work described in this paper focuses on the coordination and control of two manipulators coupled by passive elements operating in a confined space. An example of one such system is the hardware used for the environmental response treatability study funded by the Department of Energy at Oak Ridge National Laboratory (ORNL). The motivation for this project is to establish the methodology necessary to extract large volumes of hazardous waste from underground storage facilities. The hardware used at ORNL consists of two long-reach manipulators. The first robot, the Modified Light Duty Utility Arm (MLDUA), is an 8-degree-of-freedom long-reach manipulator. The second arm, the Hose Management Arm (HMA), has two active degrees-of-freedom and provides hardware to break up and extract materials from the tank. Current strategies call for the MLDUA to grasp a combined sluicing end-effector attached, by a long flexible hose, to the HMA. The MLDUA will then move the combined system through the waste, extracting material. This paper describes many of the issues related to redundancy resolution and the coordinated control of these two robots. First, the authors provide a brief outline of the project and the existing hardware. This is followed by a description of existing redundancy resolution techniques and the impact redundancy has on the success of the project. Finally, preliminary simulation results show the effect cooperative control has on the level of forces generated between the dual-arm systems when coupled by an elastic exhaust hose. These results show a significant reduction in forces when both arms are active and have a combined manipulation strategy.

  16. Dual-mixed finite elements for the three-field Stokes model as a finite volume method on staggered grids

    KAUST Repository

    Kou, Jisheng

    2017-06-09

    In this paper, a new three-field weak formulation for Stokes problems is developed, and from this, a dual-mixed finite element method is proposed on a rectangular mesh. In the proposed mixed methods, the components of stress tensor are approximated by piecewise constant functions or Q1 functions, while the velocity and pressure are discretized by the lowest-order Raviart-Thomas element and the piecewise constant functions, respectively. Using quadrature rules, we demonstrate that this scheme can be reduced into a finite volume method on staggered grid, which is extensively used in computational fluid mechanics and engineering.

  17. 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...

  18. Simulation of thin slot spirals and dual circular patch antennas using the finite element method with mixed elements

    Science.gov (United States)

    Gong, Jian; Volakis, John L.; Nurnberger, Michael W.

    1995-01-01

    This semi-annual report describes progress up to mid-January 1995. The report contains five sections all dealing with the modeling of spiral and patch antennas recessed in metallic platforms. Of significance is the development of decomposition schemes which separate the different regions of the antenna volume. Substantial effort was devoted to improving the feed model in the context of the finite element method (FEM). Finally, an innovative scheme for truncating finite element meshes is presented.

  19. Ultrasonic transducer chip assembly, ultrasound probe, ultrasonic imaging system and ultrasound assembly and probe manufacturing methods

    NARCIS (Netherlands)

    Weekamp, J.W.; Henneken, V.A.; Groenland, A.W.; Louwerse, M.C.

    2015-01-01

    Disclosed is an ultrasonic transducer assembly comprising an ultrasonic transducer chip (100) having a main surface comprising a plurality of ultrasound transducer elements (112) and a plurality of first contacts (120) for connecting to said ultrasound transducer elements; a contact chip (400) havin

  20. Application of dual reciprocity boundary element method to predict acoustic attenuation characteristics of marine engine exhaust silencers

    Institute of Scientific and Technical Information of China (English)

    JI Zhen-lin; WANG Xue-ren

    2008-01-01

    In marine engine exhaust silencing systems,the presence of exhaust gas flow influences the sound propagation inside the systems and the acoustic attenuation performance of silencers.In order to investigate the effects of three-dimensional gas flow and acoustic damping on the acoustic attenuation characteristics of marine engine exhaust silencers,a dual reciprocity boundary element method (DRBEM)was developed.The acoustic governing equation in three-dimensional potential flow was derived first,and then the DRBEM numerical procedure is given.Compared to the conventional boundary elementmethod (CBEM),the DRBEM considers the second order terms of flow Mach number in the acoustic governing equation,so it is suitable for the cases with higher Mach number subsonic flow.For complex exhaust silencers,it is difficult to apply the single-domain boundary element method,so a substructure approach based on the dual reciprocity boundary element method is presented.The experiments for measuring transmission loss of silencers are conducted,and the experimental setup and measurements are explained.The transmission loss of a single expansion chamber silencer with extended inlet and outlet were predicted by DRBEM and compared with the measurements.The good agreements between predictions and measurements are observed,which demonstrated that the derived acoustic governing equation and the DRBEM numerical procedure in the present study are correct.

  1. A mixed finite element method for nearly incompressible elasticity and Stokes equations using primal and dual meshes with quadrilateral and hexahedral grids

    OpenAIRE

    Bishnu P. Lamichhane

    2013-01-01

    We consider a mixed finite element method for approximating the solution of nearly incompressible elasticity and Stokes equations. The finite element method is based on quadrilateral and hexahedral triangulation using primal and dual meshes. We use the standard bilinear and trilinear finite element space enriched with element-wise defined bubble functions with respect to the primal mesh for the displacement or velocity, whereas the pressure space is discretised by using a piecewise constant f...

  2. 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.

  3. Histotripsy Lesion Formation Using an Ultrasound Imaging Probe Enabled by a Low-Frequency Pump Transducer.

    Science.gov (United States)

    Lin, Kuang-Wei; Hall, Timothy L; Xu, Zhen; Cain, Charles A

    2015-08-01

    When histotripsy pulses shorter than 2 cycles are applied, the formation of a dense bubble cloud relies only on the applied peak negative pressure (p-) exceeding the "intrinsic threshold" of the medium (absolute value of 26-30 MPa in most soft tissues). It has been found that a sub-threshold high-frequency probe pulse (3 MHz) can be enabled by a sub-threshold low-frequency pump pulse (500 kHz) where the sum exceeds the intrinsic threshold, thus generating lesion-producing dense bubble clouds ("dual-beam histotripsy"). Here, the feasibility of using an imaging transducer to provide the high-frequency probe pulse in the dual-beam histotripsy approach is investigated. More specifically, an ATL L7-4 imaging transducer (Philips Healthcare, Andover, MA, USA), pulsed by a V-1 Data Acquisition System (Verasonics, Redmond, WA, USA), was used to generate the high-frequency probe pulses. The low-frequency pump pulses were generated by a 20-element 345-kHz array transducer, driven by a custom high-voltage pulser. These dual-beam histotripsy pulses were applied to red blood cell tissue-mimicking phantoms at a pulse repetition frequency of 1 Hz, and optical imaging was used to visualize bubble clouds and lesions generated in the red blood cell phantoms. The results indicated that dense bubble clouds (and resulting lesions) were generated when the p- of the sub-threshold pump and probe pulses combined constructively to exceed the intrinsic threshold. The average size of the smallest reproducible lesions using the imaging probe pulse enabled by the sub-threshold pump pulse was 0.7 × 1.7 mm, whereas that using the supra-threshold pump pulse alone was 1.4 × 3.7 mm. When the imaging transducer was steered laterally, bubble clouds and lesions were steered correspondingly until the combined p- no longer exceeded the intrinsic threshold. These results were also validated with ex vivo porcine liver experiments. Using an imaging transducer for dual-beam histotripsy can have two

  4. 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...

  5. 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

  6. 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.

  7. 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

  8. Micromachined Integrated Transducers for Ultrasound Imaging

    DEFF Research Database (Denmark)

    la Cour, Mette Funding

    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...... 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...... resolution it is however necessary to develop new fabrication methods that allows fabrication of transducer elements with smaller dimensions. By using microfabrication technology it is possible to push the dimensions down and provide higher design flexibility. This project is part of a large ultrasound...

  9. 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.

  10. Elongation Transducer For Tensile Tests

    Science.gov (United States)

    Roberts, Paul W.; Stokes, Thomas R.

    1994-01-01

    Extensometer transducer measures elongation of tensile-test specimen with negligible distortion of test results. Used in stress-versus-strain tests of small specimens of composite materials. Clamping stress distributed more evenly. Specimen clamped gently between jaw and facing surface of housing. Friction force of load points on conical tips onto specimen depends on compression of spring, adjusted by turning cover on housing. Limp, light nylon-insulated electrical leads impose minimal extraneous loads on measuring elements.

  11. Finite element analysis of non-isothermal warm deep drawing of dual phase steel

    Directory of Open Access Journals (Sweden)

    Pepelnjak T.

    2016-01-01

    Full Text Available Improving the formability of the material is an important issue in the deep drawing process. Heating the material above its recrystallization temperature drastically increases formability but in the case of dual phase (DP steels it results in the loss of their mechanical properties. To improve the drawing ratio, only the heating of the flange region in the warm temperature range up to 300°C was studied on DP600 sheet steel by numerical simulation. Thermo-elastic-plastic FEM analysis of deep drawing at several drawing ratios was performed and compared with experimental results.

  12. Iterative reconstruction of the transducer surface velocity.

    Science.gov (United States)

    Alles, Erwin; van Dongen, Koen

    2013-05-01

    Ultrasound arrays used for medical imaging consist of many elements placed closely together. Ideally, each element vibrates independently. However, because of mechanical coupling, crosstalk between neighboring elements may occur. To quantify the amount of crosstalk, the transducer velocity distribution should be measured. In this work, a method is presented to reconstruct the velocity distribution from far-field pressure field measurements acquired over an arbitrary surface. The distribution is retrieved from the measurements by solving an integral equation, derived from the Rayleigh integral of the first kind, using a conjugate gradient inversion scheme. This approach has the advantages that it allows for arbitrary transducer and pressure field measurement geometries, as well as the application of regularization techniques. Numerical experiments show that measuring the pressure field along a hemisphere enclosing the transducer yields significantly more accurate reconstructions than measuring along a parallel plane. In addition, it is shown that an increase in accuracy is achieved when the assumption is made that all points on the transducer surface vibrate in phase. Finally, the method has been tested on an actual transducer with an active element of 700 × 200 μm which operates at a center frequency of 12.2 MHz. For this transducer, the velocity distribution has been reconstructed accurately to within 50 μm precision from pressure measurements at a distance of 1.98 mm (=16λ0) using a 200-μm-diameter needle hydrophone.

  13. Model of a Piezoelectric Transducer

    Science.gov (United States)

    Goodenow, Debra

    2004-01-01

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

  14. 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.

  15. Versatile photonic microwave waveforms generation using a dual-parallel Mach-Zehnder modulator without other dispersive elements

    Science.gov (United States)

    Bai, Guang-Fu; Hu, Lin; Jiang, Yang; Tian, Jing; Zi, Yue-Jiao; Wu, Ting-Wei; Huang, Feng-Qin

    2017-08-01

    In this paper, a photonic microwave waveform generator based on a dual-parallel Mach-Zehnder modulator is proposed and experimentally demonstrated. In this reported scheme, only one radio frequency signal is used to drive the dual-parallel Mach-Zehnder modulator. Meanwhile, dispersive elements or filters are not required in the proposed scheme, which make the scheme simpler and more stable. In this way, six variables can be adjusted. Through the different combinations of these variables, basic waveforms with full duty and small duty cycle can be generated. Tunability of the generator can be achieved by adjusting the frequency of the RF signal and the optical carrier. The corresponding theoretical analysis and simulation have been conducted. With guidance of theory and simulation, proof-of-concept experiments are carried out. The basic waveforms, including Gaussian, saw-up, and saw-down waveforms, with full duty and small duty cycle are generated at the repetition rate of 2 GHz. The theoretical and simulation results agree with the experimental results very well.

  16. 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

  17. 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.

  18. 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...... depended, nonlinear and high bias voltage for linearization) must be developed. This paper analyzes power stages and bias configurations suitable for driving an electrostatic transducer. Measurement results of a 300 V prototype amplifier are shown. Measuring THD across a high impedance source is discussed......, and a high voltage attenuation interface for an audio analyzer is presented. THD below 0:1% is reported....

  19. Development of a MEMS dual-axis differential capacitance floating element shear stress sensor

    Energy Technology Data Exchange (ETDEWEB)

    Barnard, Casey [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States); Griffin, Benjamin [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-09-01

    A single-axis MEMS wall shear stress sensor with differential capacitive transduction method is produced. Using a synchronous modulation and demodulation interface circuit, the system is capable of making real time measurements of both mean and fluctuating wall shear stress. A sensitivity of 3.44 mV/Pa is achieved, with linearity in response demonstrated up to testing limit of 2 Pa. Minimum detectable signals of 340 μPa at 100 Hz and 120 μPa at 1 kHz are indicated, with a resonance of 3.5 kHz. Multiple full scale wind tunnel tests are performed, producing spectral measurements of turbulent boundary layers in wind speeds ranging up to 0.5 Ma (18 Pa of mean wall shear stress). The compact packaging allows for minimally invasive installation, and has proven relatively robust over multiple testing events. Temperature sensitivity, likely due to poor CTE matching of packaged materials, is an ongoing concern being addressed. These successes are being directly leveraged into a development plan for a dual-axis wall shear stress sensor, capable of producing true vector estimates at the wall.

  20. Finite element analyses of a dual actuated prototype of a smart needle

    Science.gov (United States)

    Konh, Bardia; Podder, Tarun K.

    2017-04-01

    Brachytherapy is one of the most effective modalities for treating early stage prostate cancer. In this procedure, radioactive seeds are being placed in the prostate to kill the tumorous cells. Inaccurate placement of seeds can underdose the tumor and dangerously overdose the critical structures (urethra, rectum, bladder) and adjacent healthy tissues. It is very difficult, if not impossible, for the surgeons to compensate the needle misplacement errors while using the conventional passive straight needles. The smart needles actuated by shape memory alloy (SMA) wires are being developed to provide more actuation and control for the surgeons to achieve more geometric conformity. In our recent work, a prototype of a smart needle was developed where not only the actuation of SMA wires were incorporated, but also shape memory polymers (SMPs) were included in the design introducing a soft joint element to further assist the flexibility of the active surgical needles. The additional actuation of shape memory polymers provided the capability of reaching much high flexibility that was not achievable before. However, there are some disadvantages using this active SMP component compared to a passive Nylon joint component that are discussed in this work. The utilization of a heated SMP as a soft joint showed about 20% improvement in the final needle tip deflection. This work presents the finite element studies of the developed prototype. A finite element model that could accurately predict the behavior of the smart needle could be very valuable in analyzing and optimizing the future novel designs.

  1. Advanced design methodology for single and dual voltage wound core power transformers based on a particular finite element model

    Energy Technology Data Exchange (ETDEWEB)

    Tsili, Marina A.; Kladas, Antonios G. [Faculty of Electrical & amp; Computer Engineering, National Technical University of Athens, GR-15780, Athens (Greece); Georgilakis, Pavlos S. [Department of Production Engineering and Management, Technical University of Crete, GR-73100, Chania (Greece); Souflaris, Athanasios T.; Paparigas, Dimitris G. [Schneider Electric AE, Elvim Plant, GR-32011, Inofyta, Viotia (Greece)

    2006-06-15

    The paper presents an accurate and cost effective three-dimensional finite element model for the analysis and design of wound core, shell type, power transformers, focusing on the short-circuit impedance evaluation. The model efficiency lies on the detailed representation of the transformer geometry along with the adoption of a particular reduced scalar potential formulation enabling three-dimensional magnetostatic problem solution without prior source field calculation. Its accuracy is validated through local field measurements and through comparison of the calculated short-circuit impedance value with the measured one for several commercial wound core, shell type transformers. In such transformers, involving extensive winding parts out of the core window, the detailed representation of the transformer geometry, including the winding cooling ducts, provides accurate results for low densities of the three-dimensional finite element mesh, resulting to reduction of the required calculation time. The model is used in the development of a computational tool, which enables the automated and accurate transformer characteristics prediction, adopted to the manufacturing process. This tool has also been applied in the impedance calculation for different winding connections of dual voltage transformers, thus providing the information needed for the achievement of an accurate design and the enhancement of the manufacturer's ability to reduce design margins. The methodology presented in this paper has been incorporated in the design process of a transformer manufacturing industry. (author)

  2. An Inexpensive Position Transducer.

    Science.gov (United States)

    Fox, J.; And Others

    1989-01-01

    Described is a position transducer used to convert the position of an object into a voltage read by a computer with use of an interface board. The arrangement of the apparatus, electronic circuit, and typical graph displays are presented. Discussed is the instructional use of the transducer. (YP)

  3. 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.

  4. 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....

  5. 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....

  6. Dual Feed, Single Element Antenna for WiMAX MIMO Application

    Directory of Open Access Journals (Sweden)

    Frank M. Caimi

    2008-01-01

    Full Text Available A novel u-shaped single element antenna having two feed ports is compared with two equal length monopoles separated by a distance equivalent to the width. A discussion of relative performance metrics is provided for MIMO applications, and measured data is given for comparison. Good impedance match and isolation of greater than −10 dB are observed over the operating bandwidth from 2.3 to 2.39 GHz. The antenna patterns are highly uncorrelated, as illustrated by computation of the antenna pattern correlation coefficient for the two comparison monopoles.

  7. Advanced Geothermal Optical Transducer (AGOT)

    Energy Technology Data Exchange (ETDEWEB)

    None

    2004-09-01

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

  8. 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.

  9. 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

  10. Identification of the critical sequence elements in the cytoplasmic domain of leptin receptor isoforms required for Janus kinase/signal transducer and activator of transcription activation by receptor heterodimers.

    Science.gov (United States)

    Bahrenberg, Gregor; Behrmann, Iris; Barthel, Andreas; Hekerman, Paul; Heinrich, Peter Claus; Joost, Hans-Georg; Becker, Walter

    2002-04-01

    Two predominant splice variants of the leptin receptor (LEPR) are coexpressed in leptin-responsive tissues: the long form, LEPRb, characterized as the signal-transducing receptor, and the signaling-defective short form, LEPRa. It is unknown whether heterodimers of these isoforms are capable of signal transduction via the Janus kinase (JAK)/signal transducer and activator of transcription (STAT) pathway. To address this question, chimeric receptors were constructed consisting of the transmembrane and intracellular parts of LEPRb and LEPRa fused with the extracellular domains of either the alpha- or beta-subunit of the IL-5 receptor. This strategy allows the directed heterodimerization of different LEPR cytoplasmic tails and excludes homodimerization. In COS-7 and HEPG2 cells, chimeric receptor heterodimers of LEPRa and LEPRb failed to activate the JAK/STAT pathway, whereas receptor dimers of LEPRb gave rise to the expected ligand-dependent activation of JAK2, phosphorylation of STAT3, and STAT3-dependent promoter activity. Markedly lower amounts of JAK2 were found to be associated with immunoprecipitated LEPRa chimeras than with LEPRb chimeras. Analysis of a series of deletion constructs indicated that a segment of 15 amino acids in addition to the 29 amino acids common to LEPRa and LEPRb was required for partial restoration of JAK/STAT activation. Site-directed mutagenesis of the critical sequence indicated that two hydrophobic residues (Leu896, Phe897) not present in LEPRa were indispensable for receptor signaling. These findings show that LEPRa/LEPRb heterodimers cannot activate STAT3 and identify sequence elements within the LEPR that are critical for the activation of JAK2 and STAT3.

  11. The Curious Case of Elemental Abundance Differences in the Dual Hot Jupiter Hosts WASP-94AB

    CERN Document Server

    Teske, Johanna K; Ramírez, Ivan

    2016-01-01

    Binary stars provide an ideal laboratory for investigating the potential effects of planet formation on stellar composition. Assuming the stars formed in the same environment/from the same material, any compositional anomalies between binary components might indicate differences in how material was sequestered in planets, or accreted by the star in the process of planet formation. We present here a study of the elemental abundance differences between WASP-94AB, a pair of stars that each host a hot Jupiter exoplanet. The two stars are very similar in spectral type (F8 and F9), and their ~2700 AU separation suggests their protoplanetary disks were likely not influenced by stellar interactions, but WASP-94Ab's orbit -- misaligned with the host star spin axis and likely retrograde -- points towards a dynamically active formation mechanism, perhaps different than that of WASP-94Bb, which is not misaligned and has nearly circular orbit. Based on our high-quality spectra and strictly relative abundance analysis, we ...

  12. 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.

  13. 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...

  14. 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...

  15. 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...

  16. Design theory and experimental investigation of the low frequency and high power rare earth magnetostrictive flextensional transducer (I). Theoretical part

    Institute of Scientific and Technical Information of China (English)

    HE Xiping; SUN Jincai; LI Bin

    2001-01-01

    The energy relationships among all the elements, by which the magnetostrictive transducers are manufactured, in Finite Element Method (FEM) are analyzed, then the expressions of FEM dynamics equations and performances formulas for magnetostrictive transducers are derived. The vibrating modes of the class VII transducer and its shell vibration are calculated theoretically and the results point out that there is a breathing mode and if the transducer works at this mode, the transducer will vibrate with a greater volume speed and source level.

  17. Dual-mode chemical vapor generation for simultaneous determination of hydride-forming and non-hydride-forming elements by atomic fluorescence spectrometry.

    Science.gov (United States)

    Wang, Yu; Xu, Kailai; Jiang, Xiaoming; Hou, Xiandeng; Zheng, Chengbin

    2014-05-21

    A dual-mode chemical vapor generation integrating hydride generation and photochemical vapor generation was developed for simultaneous multi-element analysis of hydride-forming and non-hydride-forming elements by atomic fluorescence spectrometry. Four elements were selected as model elements of hydride-forming (As, Cd) and non-hydride-forming (Ni, Fe) elements to validate this proposed method. Standard or sample solutions were separately pumped to mix with tetrahydroborate, and concentrated formic acid and ammonia, and then directed to a hydride generator and a photochemical reactor to realize simultaneous hydride generation and photochemical vapor generation, respectively. Optimum conditions for dual-mode chemical vapor generation were carefully investigated. Under the optimized conditions, limits of detection of 0.05, 0.008, 0.8 and 0.1 μg L(-1) were obtained for As, Cd, Fe and Ni, respectively. The precisions were 5.0, 5.5, 4.3 and 4.5% (n = 6, RSDs) for 2 μg L(-1) of As, 1 μg L(-1) of Cd, 50 μg L(-1) of Fe and 10 μg L(-1) of Ni, respectively. This method was validated for accuracy with three certified reference water samples and applied to the simultaneous determination of these elements in a tap water sample with spike recoveries in the range of 95-99%.

  18. Dual Transformer Model based on Standard Circuit Elements for the Study of Low- and Mid-frequency Transients

    Science.gov (United States)

    Jazebi, Saeed

    This thesis is a step forward toward achieving the final objective of creating a fully dual model for transformers including eddy currents and nonlinearities of the iron core using the fundamental electrical components already available in the EMTP-type programs. The model is effective for the study of the performance of transformers during power system transients. This is very important for transformer designers, because the insulation of transformers is determined with the overvoltages caused by lightning or switching operations. There are also internally induced transients that occur when a switch is actuated. For example switching actions for reconfiguration of distribution systems that offers economic advantages, or protective actions to clear faults and large short-circuit currents. Many of the smart grid concepts currently under development by many utilities rely heavily on switching to optimize resources that produce transients in the system. On the other hand, inrush currents produce mechanical forces which deform transformer windings and cause malfunction of the differential protection. Also, transformer performance under ferroresonance and geomagnetic induced currents are necessary to study. In this thesis, a physically consistent dual model applicable to single-phase two-winding transformers is proposed. First, the topology of a dual electrical equivalent circuit is obtained from the direct application of the principle of duality. Then, the model parameters are computed considering the variations of the transformer electromagnetic behavior under various operating conditions. Current modeling techniques use different topological models to represent diverse transient situations. The reversible model proposed in this thesis unifies the terminal and topological equivalent circuits. The model remains invariable for all low-frequency transients including deep saturation conditions driven from any of the two windings. The very high saturation region of the

  19. 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....

  20. 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.

  1. 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.

  2. 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.

  3. Design optimization of embedded ultrasonic transducers for concrete structures assessment.

    Science.gov (United States)

    Dumoulin, Cédric; Deraemaeker, Arnaud

    2017-08-01

    In the last decades, the field of structural health monitoring and damage detection has been intensively explored. Active vibration techniques allow to excite structures at high frequency vibrations which are sensitive to small damage. Piezoelectric PZT transducers are perfect candidates for such testing due to their small size, low cost and large bandwidth. Current ultrasonic systems are based on external piezoelectric transducers which need to be placed on two faces of the concrete specimen. The limited accessibility of in-service structures makes such an arrangement often impractical. An alternative is to embed permanently low-cost transducers inside the structure. Such types of transducers have been applied successfully for the in-situ estimation of the P-wave velocity in fresh concrete, and for crack monitoring. Up to now, the design of such transducers was essentially based on trial and error, or in a few cases, on the limitation of the acoustic impedance mismatch between the PZT and concrete. In the present study, we explore the working principles of embedded piezoelectric transducers which are found to be significantly different from external transducers. One of the major challenges concerning embedded transducers is to produce very low cost transducers. We show that a practical way to achieve this imperative is to consider the radial mode of actuation of bulk PZT elements. This is done by developing a simple finite element model of a piezoelectric transducer embedded in an infinite medium. The model is coupled with a multi-objective genetic algorithm which is used to design specific ultrasonic embedded transducers both for hard and fresh concrete monitoring. The results show the efficiency of the approach and a few designs are proposed which are optimal for hard concrete, fresh concrete, or both, in a given frequency band of interest. Copyright © 2017 Elsevier B.V. All rights reserved.

  4. 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.

  5. 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.

  6. Ultrasound transducer positioning aid for fetal heart rate monitoring.

    Science.gov (United States)

    Hamelmann, Paul; Kolen, Alex; Schmitt, Lars; Vullings, Rik; van Assen, Hans; Mischi, Massimo; Demi, Libertario; van Laar, Judith; Bergmans, Jan

    2016-08-01

    Fetal heart rate (fHR) monitoring is usually performed by Doppler ultrasound (US) techniques. For reliable fHR measurements it is required that the fetal heart is located within the US beam. In clinical practice, clinicians palpate the maternal abdomen to identify the fetal presentation and then the US transducer is fixated on the maternal abdomen where the best fHR signal can be obtained. Finding the optimal transducer position is done by listening to the strength of the Doppler audio output and relying on a signal quality indicator of the cardiotocographic (CTG) measurement system. Due to displacement of the US transducer or displacement of the fetal heart out of the US beam, the fHR signal may be lost. Therefore, it is often necessary that the obstetrician repeats the tedious procedure of US transducer positioning to avoid long periods of fHR signal loss. An intuitive US transducer positioning aid would be highly desirable to increase the work flow for the clinical staff. In this paper, the possibility to determine the fetal heart location with respect to the transducer by exploiting the received signal power in the transducer elements is shown. A commercially available US transducer used for fHR monitoring is connected to an US open platform, which allows individual driving of the elements and raw US data acquisition. Based on the power of the received Doppler signals in the transducer elements, the fetal heart location can be estimated. A beating fetal heart setup was designed and realized for validation. The experimental results show the feasibility of estimating the fetal heart location with the proposed method. This can be used to support clinicians in finding the optimal transducer position for fHR monitoring more easily.

  7. DIRECTIVITY PATTERN INVESTIGATION OF DUAL FIBER OPTIC HYDROPHONE

    Directory of Open Access Journals (Sweden)

    M. E. Efimov

    2015-11-01

    Full Text Available Subject of Research. The paper provides comparison of theoretical and experimental research results of directivity pattern of dual fiber optic hydrophone at various acoustic frequencies. Application of multiple fiber optic transducers in fiber optic hydrophone design placed in sensitive arm of the interferometer gives the possibility for increasing the sensitivity of a fiber optic hydrophone without changing the fiber-optic transducers. In the simplest case, such fiber optic hydrophone can be built on the basis of two spatially separated acoustic transducers. However, this diversity inevitably leads to the directivity pattern unevenness of the fiber optic hydrophone at acoustic frequencies which wavelengths are commensurate with the size of the transducers system. Method. Mathematical model has been created and it became the base material for a theoretical study of two acoustic transducers system in Mathcad environment. Directivity pattern was described by a mathematical formula, depending on the frequency of the acoustic impact and the distance between sensors. To confirm the correctness of theoretical research of the directivity pattern, dual fiber optic hydrophone on Bragg gratings was produced and investigated experimentally. It consists of two consequently welded sensitive elements with a 9 cm distance between them. In trials carried out in open water conditions, fiber-optic hydrophone was placed on the rotator and rotated relative to the piezoceramic emitter for 360 degrees. During investigation, the signal from a fiber optic hydrophone has been recorded simultaneously with the rotation. Further, after the data processing in MATLAB, amplitude of the measured phase signal and the directivity pattern of the test sample were estimated. Amplitude estimation of the measured phase signal and directivity pattern creation of the sample was performed at frequencies equal to 1000, 3000 and 8000 Hz. Main Results. Sensitivity of the dual fiber optic

  8. 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.

  9. 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.

  10. 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

  11. Fluid force transducer

    Science.gov (United States)

    Jendrzejczyk, Joseph A.

    1982-01-01

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

  12. 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...

  13. 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.

  14. Certified dual-corrected radiation patterns of phased antenna arrays by offline–online order reduction of finite-element models

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, A., E-mail: a.sommer@lte.uni-saarland.de; Farle, O., E-mail: o.farle@lte.uni-saarland.de; Dyczij-Edlinger, R., E-mail: edlinger@lte.uni-saarland.de

    2015-10-15

    This paper presents a fast numerical method for computing certified far-field patterns of phased antenna arrays over broad frequency bands as well as wide ranges of steering and look angles. The proposed scheme combines finite-element analysis, dual-corrected model-order reduction, and empirical interpolation. To assure the reliability of the results, improved a posteriori error bounds for the radiated power and directive gain are derived. Both the reduced-order model and the error-bounds algorithm feature offline–online decomposition. A real-world example is provided to demonstrate the efficiency and accuracy of the suggested approach.

  15. 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...

  16. 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...

  17. 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.

  18. Piezoelectric single crystals for ultrasonic transducers in biomedical applications

    Science.gov (United States)

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

    2014-01-01

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

  19. Finite Element Analysis of Steel Thinning Defect Detection of Electromagnetic Acoustic Transducer Shear Wave%电磁超声横波检测钢板减薄缺陷的有限元分析

    Institute of Scientific and Technical Information of China (English)

    徐文峰; 赵建平

    2016-01-01

    The shear waves in measured specimen excitated by EMAT(electromagnetic acoustic transduc-er)can be applied to detect thickness and internal defect of specimen.Finite element analysis was applied to simulate the mechanism of electromagnetic ultrasonic excitation of shear wave.Through the es-tablishment of three-dimensional model of EMAT and electromagnetism coupling calculation,the distribu-tion of the surface magnetic field,eddy current and Lorenz force were obtained,the results show the mech-anism of EMAT wave excitation,which provides reference for the design of the electromagnetic ultrasonic transducer.With the coupling of electromagnetics and structural dynamics calculation,the propagation of shear waves in the specimen thickness direction was obtained,results show that the shear wave propagates in the specimen along the thickness direction,and the energy is attenuated trend.In addition,the structure dynamics analysis of the defective plate provides that the wave fluctuations occur obvious change and decay when they encounter the defect.It proves the wave excitation of EMAT can effectively detect the de-fects inside the specimen.According to the results of simulation and experiments,the method of quantitati-ving defect by shear wave detection was put forward.%电磁超声换能器(EMAT)在试件中激发的横波(剪切波)能够应用于试件厚度和内部缺陷检测,为了研究电磁超声激发横波的机理,采用有限元分析的方法,对其进行仿真分析。通过建立EMAT三维模型,进行电磁学耦合计算,获得被测试件表面磁场、涡流、洛伦兹力的分布规律,显示了EMAT激发横波的机理过程,为电磁超声换能器的设计提供参考;通过电磁学与动力学的耦合计算,获得横波在试件厚度方向的传播规律,结果表明,横波在试件中沿厚度方向传播,并且能量呈衰减趋势;对含缺陷钢板进行结构动力学分析,发现当波传播遇到缺

  20. 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

  1. Simple method for measuring vibration amplitude of high power airborne ultrasonic transducer: using thermo-couple.

    Science.gov (United States)

    Saffar, Saber; Abdullah, Amir

    2014-03-01

    Vibration amplitude of transducer's elements is the influential parameters in the performance of high power airborne ultrasonic transducers to control the optimum vibration without material yielding. The vibration amplitude of elements of provided high power airborne transducer was determined by measuring temperature of the provided high power airborne transducer transducer's elements. The results showed that simple thermocouples can be used both to measure the vibration amplitude of transducer's element and an indicator to power transmission to the air. To verify our approach, the power transmission to the air has been investigated by other common method experimentally. The experimental results displayed good agreement with presented approach. Copyright © 2013 Elsevier B.V. All rights reserved.

  2. Applying of the array transducers' technology for surface acoustic waves materials characterization in the transient regime; Application de la technologie multi-elements a la caracterisation des materiaux par ondes acoustiques de surface en regime impulsionnel

    Energy Technology Data Exchange (ETDEWEB)

    Frenet, D

    2000-07-01

    In this document we present a theoretical and experimental study which has been led to design a surface acoustic wave device for local characterisation (relatively to the wavelength) of isotropic or anisotropic materials. The device is based on a phased-array transducer of conical shape we have specifically designed for this purpose. It operates in the impulsive mode, in the frequency range of 1-5 MHz. In order to deduce mechanical properties of the material, it is possible to measure the surface wave characteristics (velocity, attenuation,...). Different methods for measuring the wave velocity have been developed taking advantage of from the phased-array technology. The originality of theses methods relies on the fact that the measures are performed without moving the transducer. Consequently, the device requires no additional mechanical system and it is quite compact. In addition, this shortens the characterisation process duration comparatively to the usually available methods (e. g. the V(z) technique). In the theoretical section of this study, a versatile model allowing to simulate in the time harmonic regime as well as in the transient regime, the transmitted field, the field reflected on isotropic or anisotropic planar samples and the output voltage for transducers of arbitrary shapes has been developed. The model has been applied to the phased-array conical transducer as well as to more classical transducers such as planar (rectangular) or focusing (spherically or cylindrically shaped) transducers. It predicts not only the geometrical contributions of the reflected field and signal but also the leaky contributions related to the surface acoustic waves. (author)

  3. 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.

  4. Mixed dual finite element methods for the numerical treatment of the diffusion equation in hexagonal geometry; Elements finis mixtes duaux pour la resolution numerique de l'equation de la diffusion neutronique en geometrie hexagonale

    Energy Technology Data Exchange (ETDEWEB)

    Schneider, D

    2001-07-01

    The nodal method Minos has been developed to offer a powerful method for the calculation of nuclear reactor cores in rectangular geometry. This method solves the mixed dual form of the diffusion equation and, also of the simplified P{sub N} approximation. The discretization is based on Raviart-Thomas' mixed dual finite elements and the iterative algorithm is an alternating direction method, which uses the current as unknown. The subject of this work is to adapt this method to hexagonal geometry. The guiding idea is to construct and test different methods based on the division of a hexagon into trapeze or rhombi with appropriate mapping of these quadrilaterals onto squares in order to take into advantage what is already available in the Minos solver. The document begins with a review of the neutron diffusion equation. Then we discuss its mixed dual variational formulation from a functional as well as from a numerical point of view. We study conformal and bilinear mappings for the two possible meshing of the hexagon. Thus, four different methods are proposed and are completely described in this work. Because of theoretical and numerical difficulties, a particular treatment has been necessary for methods based on the conformal mapping. Finally, numerical results are presented for a hexagonal benchmark to validate and compare the four methods with respect to pre-defined criteria. (authors)

  5. 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.

  6. Investigation of the dynamic characteristics of a dual rotor system and its start-up simulation based on finite element method

    Institute of Scientific and Technical Information of China (English)

    Zhong-xiu FEI; Shui-guang TONG; Chao WEI

    2013-01-01

    Recently,the finite element method (FEM) has been commonly applied in the engineering analysis of rotor dynamics.Gyroscopic moments,rotary inertia,transverse shear deformation and gravity can be included in computational models of rotor-bearing systems.In this paper,a finite element model and its solution method are presented for the calculation of the dynamics of dual rotor systems.A typical structure with two rotor shafts is discussed and the procedure for obtaining the coupling motion equations of the subsystems is illustrated.A computer program is developed to solve critical speeds and to simulate the transient motion.The influence of gyroscopic moments on co-rotation and counter-rotation is analyzed,and the effect of the speed ratio on critical speed is studied.The dynamic characteristics under different conditions of increasing speed during start-up are demonstrated by comparison with transient nodal displacements.The presented model provides a complete foundation for further investigation of the dynamics of dual rotor systems.

  7. 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...

  8. Parameter sensitivity study of a Field II multilayer transducer model on a convex transducer

    DEFF Research Database (Denmark)

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

    2009-01-01

    .ResultsPredictions using the ZR give a pressure pulse error (PPE) and an intensity error (IE) of 32 % and 23 %, respectively, relative to the measured. Altering the piezoelectric permittivity +12 % from ZR decreases the PPE to 30 % and the IE to 2 % relative to the measured. Changing the stiffness constant of the lens -4......A multilayer transducer model for predicting a transducer impulse response has in earlier works been developed and combined with the Field II software. This development was tested on current, voltage, and intensity measurements on piezoceramics discs (Bæk et al. IUS 2008) and a convex 128 element...... ultrasound imaging transducer (Bæk et al. ICU 2009). The model benefits from its 1D simplicity and hasshown to give an amplitude error around 1.7‐2 dB. However, any prediction of amplitude, phase, and attenuation of pulses relies on the accuracy of manufacturer supplied material characteristics, which may...

  9. Wellbore pressure transducer

    Science.gov (United States)

    Shuck, Lowell Z.

    1979-01-01

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

  10. RADIO-ACTIVE TRANSDUCER

    Science.gov (United States)

    Wanetick, S.

    1962-03-01

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

  11. 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.

  12. 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...

  13. 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.

  14. MGMT enrichment and second gene co-expression in hematopoietic progenitor cells using separate or dual-gene lentiviral vectors.

    Science.gov (United States)

    Roth, Justin C; Alberti, Michael O; Ismail, Mourad; Lingas, Karen T; Reese, Jane S; Gerson, Stanton L

    2015-01-22

    The DNA repair gene O(6)-methylguanine-DNA methyltransferase (MGMT) allows efficient in vivo enrichment of transduced hematopoietic stem cells (HSC). Thus, linking this selection strategy to therapeutic gene expression offers the potential to reconstitute diseased hematopoietic tissue with gene-corrected cells. However, different dual-gene expression vector strategies are limited by poor expression of one or both transgenes. To evaluate different co-expression strategies in the context of MGMT-mediated HSC enrichment, we compared selection and expression efficacies in cells cotransduced with separate single-gene MGMT and GFP lentivectors to those obtained with dual-gene vectors employing either encephalomyocarditis virus (EMCV) internal ribosome entry site (IRES) or foot and mouth disease virus (FMDV) 2A elements for co-expression strategies. Each strategy was evaluated in vitro and in vivo using equivalent multiplicities of infection (MOI) to transduce 5-fluorouracil (5-FU) or Lin(-)Sca-1(+)c-kit(+) (LSK)-enriched murine bone marrow cells (BMCs). The highest dual-gene expression (MGMT(+)GFP(+)) percentages were obtained with the FMDV-2A dual-gene vector, but half of the resulting gene products existed as fusion proteins. Following selection, dual-gene expression percentages in single-gene vector cotransduced and dual-gene vector transduced populations were similar. Equivalent MGMT expression levels were obtained with each strategy, but GFP expression levels derived from the IRES dual-gene vector were significantly lower. In mice, vector-insertion averages were similar among cells enriched after dual-gene vectors and those cotransduced with single-gene vectors. These data demonstrate the limitations and advantages of each strategy in the context of MGMT-mediated selection, and may provide insights into vector design with respect to a particular therapeutic gene or hematologic defect.

  15. 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...

  16. 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...

  17. Numerical comparison of patch and sandwich piezoelectric transducers for transmitting ultrasonic waves

    Science.gov (United States)

    Loveday, Philip W.

    2006-03-01

    Guided wave ultrasonic inspection is becoming an important method of non-destructive testing for long, slender structures such as pipes and rails. Often it is desirable to use transducers that can strongly excite a specific mode of wave propagation in the waveguide. Piezoelectric patch transducers are frequently employed, by researchers, for exciting waves in beam like structures. Sonar systems frequently make use of resonant transducers, such as sandwich transducers, for acoustic wave generation and this principle has been used to excite waves in a rail. This paper compares the two transduction approaches, for launching bending waves in rectangular waveguides, with numerical modeling. The numerical modeling combined a waveguide finite element model, of the waveguide, with conventional three-dimensional piezoelectric finite element models of the transducers. The waveguide finite elements were formulated using a complex exponential to describe the wave propagation along the structure and conventional finite element interpolation over the area of the element. Consequently, only a two-dimensional finite element mesh covering the cross-section of the waveguide is required. The harmonic forced response of the waveguide was used to compute a complex dynamic stiffness matrix which represented the waveguide in the transducer model. The effects of geometrical parameters of patch and sandwich transducers were considered before the comparison was made. It appears that piezoelectric patch transducers offer advantages at low frequencies while sandwich transducers are superior at high frequencies, where resonance can be exploited, at the cost of more complex design.

  18. 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.

  19. Superconducting Qubit Optical Transducer (SQOT)

    Science.gov (United States)

    2015-08-05

    SECURITY CLASSIFICATION OF: The SQOT (Superconducting Qubit Optical Transducer ) project proposes to build a novel electro-optic system which can...Apr-2015 Approved for Public Release; Distribution Unlimited Final Report: "Superconducting Qubit Optical Transducer " (SQOT) The views, opinions and...journals: Number of Papers published in non peer-reviewed journals: Final Report: "Superconducting Qubit Optical Transducer " (SQOT) Report Title The

  20. Ultrasonic measurements of surface defects on flexible circuits using high-frequency focused polymer transducers

    Science.gov (United States)

    Wagle, Sanat; Habib, Anowarul; Melandsø, Frank

    2017-07-01

    High-frequency transducers made from a layer-by-layer deposition method are investigated as transducers for ultrasonic imaging. Prototypes of adhesive-free transducers with four active elements were made on a high-performance poly(ether imide) substrate with precision milled spherical cavities used to produce focused ultrasonic beams. The transducer prototypes were characterized using a pulse-echo experimental setup in a water tank using a glass plate as a reflector. Then, transducer was used in a three-dimensional ultrasonic scanning tank, to produce high-resolution ultrasonic images of flexible electronic circuits with the aim to detect defects in the outermost cover layer.

  1. 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

  2. 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.

  3. Electromagnetic acoustic transducer

    Science.gov (United States)

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

    1988-01-01

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

  4. 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.

  5. On a New Optical Transducer

    Directory of Open Access Journals (Sweden)

    Cornel Bit

    2015-07-01

    Full Text Available This paper presents a new type of mechano – optical force transducer which to be used in different mechanical experimental investigations. This transducer has been integrated within a mechanical modulus, providing a useful tool for this kind of measurements. The use of optical methods for the elastic contact measurements has several important advantages.

  6. 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.

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

    DEFF Research Database (Denmark)

    Jensen, Jørgen Arendt; Bæk, David

    2010-01-01

    The FIELD II simulation program can be used for simulating any kind of linear ultrasound fields. The program is capable of describing multi-element transducers used with any kind of excitation, apodization, and focusing. The program has been widely used in both academia and by commercial ultrasound...... 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...

  8. Proposed low-energy absolute calibration of nuclear recoils in a dual-phase noble element TPC using D-D neutron scattering kinematics

    Science.gov (United States)

    Verbus, J. R.; Rhyne, C. A.; Malling, D. C.; Genecov, M.; Ghosh, S.; Moskowitz, A. G.; Chan, S.; Chapman, J. J.; de Viveiros, L.; Faham, C. H.; Fiorucci, S.; Huang, D. Q.; Pangilinan, M.; Taylor, W. C.; Gaitskell, R. J.

    2017-04-01

    We propose a new technique for the calibration of nuclear recoils in large noble element dual-phase time projection chambers used to search for WIMP dark matter in the local galactic halo. This technique provides an in situ measurement of the low-energy nuclear recoil response of the target media using the measured scattering angle between multiple neutron interactions within the detector volume. The low-energy reach and reduced systematics of this calibration have particular significance for the low-mass WIMP sensitivity of several leading dark matter experiments. Multiple strategies for improving this calibration technique are discussed, including the creation of a new type of quasi-monoenergetic neutron source with a minimum possible peak energy of 272 keV. We report results from a time-of-flight-based measurement of the neutron energy spectrum produced by an Adelphi Technology, Inc. DD108 neutron generator, confirming its suitability for the proposed nuclear recoil calibration.

  9. Proposed low-energy absolute calibration of nuclear recoils in a dual-phase noble element TPC using D-D neutron scattering kinematics

    CERN Document Server

    Verbus, J R; Malling, D C; Genecov, M; Ghosh, S; Moskowitz, A G; Chan, S; Chapman, J J; de Viveiros, L; Faham, C H; Fiorucci, S; Huang, D Q; Pangilinan, M; Taylor, W C; Gaitskell, R J

    2016-01-01

    We propose a new technique for the calibration of nuclear recoils in large noble element dual-phase time projection chambers used to search for WIMP dark matter in the local galactic halo. This technique provides an $\\textit{in situ}$ measurement of the low-energy nuclear recoil response of the target media using the measured scattering angle between multiple neutron interactions within the detector volume. The low-energy reach and reduced systematics of this calibration have particular significance for the low-mass WIMP sensitivity of several leading dark matter experiments. Multiple strategies for improving this calibration technique are discussed, including the creation of a new type of quasi-monoenergetic 272 keV neutron source. We report results from a time-of-flight based measurement of the neutron energy spectrum produced by an Adelphi Technology, Inc. DD108 neutron generator, confirming its suitability for the proposed nuclear recoil calibration.

  10. 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

  11. 汉魏六朝碑刻中的双形符字和双声符字%The Characters with Dual Pictographic Elements and Characters with Dual Phonetic Elements in the Inscription on Stele in Han Wei and Six Dynasties

    Institute of Scientific and Technical Information of China (English)

    吴继刚

    2014-01-01

    The characters with dual pictographic elements and characters with dual phonetic elements in the inscrip-tion on stele in Han Wei and Six Dynasties are the inevitable outcome in the course of development of Chinese char-acter , which include diachronic inherited characters and synchronic coined characters . The comparative study shows that the character with dual pictographic elements is an important type of Chinese pictophonetic character and it is in different historical levels , reflecting the priority of indicating a general category of meaning in Chinese pic-tographic character . The character with dual phonetic elements is the representation of chinese characters indica-ting sound and the outcome of character change . The study contributes to enriching the theory of Chinese character structure , discussing the structure reason of Chinese character form , textual research and explaining ancient char-acters . It has the theoritical significance and practical value to do the textual research and explain the ancient Chi-nese characters and variant form of a Chinese character.%汉魏六朝碑刻双形符字、双声符字既有历时传承字,又有共时新造字,是汉字意音文字发展过程中的必然产物。比较研究表明,双形符字是汉字形声字的一种重要类型,其双形符处于不同的历史层次,是形声字形义优先的反映;双声符字是汉字表音化的体现和文字讹变的结果。研究这两类文字现象对于丰富汉字结构理论,探讨汉字形体结构理据,考释古文字与隶变之后异体字具有重要理论意义和实践价值。

  12. High frequency PMN-PT single crystal focusing transducer fabricated by a mechanical dimpling technique.

    Science.gov (United States)

    Chen, Y; Lam, K H; Zhou, D; Cheng, W F; Dai, J Y; Luo, H S; Chan, H L W

    2013-02-01

    High frequency (∼30MHz and ∼80MHz) focusing ultrasound transducers were fabricated using a PMN-0.28PT single crystal by a mechanical dimpling technique. The dimpled single crystal was used as an active element for the focusing transducer. Compared with a plane transducer, the focusing transducer fabricated with a dimpled active element exhibits much broader bandwidth and higher sensitivity. Besides, a high quality image can be obtained by the 30MHz focusing transducer, in which the -6dB axial and lateral resolution is 27μm and 139μm, respectively. These results prove that the dimpling technique is capable to fabricate the high frequency focusing transducers with excellent performance for imaging applications.

  13. Micromachined capacitive transducer arrays for intravascular ultrasound

    Science.gov (United States)

    Degertekin, F. Levent; Guldiken, R. Oytun; Karaman, Mustafa

    2005-01-01

    Intravascular ultrasound (IVUS) imaging has become an essential imaging modality for the effective diagnosis and treatment of cardiovascular diseases during the past decade enabled by innovative applications of piezoelectric transducer technology. The limitations in the manufacture and performance of the same piezoelectric transducers have also impeded the improvement of IVUS for emerging clinically important applications such as forward viewing arrays for guiding interventions and high resolution imaging of arterial structure such as vulnerable plaque and fibrous cap, and also implementation of techniques such as harmonic imaging of the tissue and of the contrast agents. Capacitive micromachined ultrasonic transducer (CMUT) technology shows great potential for transforming IVUS not only to satisfy these clinical needs but also to open up possibilities for low-cost imaging devices integrated to therapeutic tools. We have developed manufacturing processes with a maximum process temperature of 250°C to build CMUTs on the same silicon chip with integrated electronics. Using these processes we fabricated CMUT arrays suitable for forward viewing IVUS in the 10-20MHz range. We characterized these array elements in terms of pulse-echo response, radiation pattern measurements and demonstrated its volumetric imaging capabilities on various imaging targets.

  14. Cross-fiber Bragg grating transducer

    Science.gov (United States)

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

    2000-01-01

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

  15. A Finite-Element Coarse-Grid Projection Method: A Dual Acceleration/Mesh Refinement Tool for Incompressible Flows

    CERN Document Server

    Kashefi, A

    2016-01-01

    Coarse grid projection (CGP) methodology is a novel multigrid method for systems involving decoupled nonlinear evolution equations and linear elliptic Poisson equations. The nonlinear equations are solved on a fine grid and the linear equations are solved on a corresponding coarsened grid. Mapping operators execute data transfer between the grids. The CGP framework is constructed upon spatial and temporal discretization schemes. This framework has been established for finite volume/difference discretizations as well as explicit time integration methods. In this article we present for the first time a version of CGP for finite element discretizations, which uses a semi-implicit time integration scheme. The mapping functions correspond to the finite-element shape functions. With the novel data structure introduced, the mapping computational cost becomes insignificant. We apply CGP to pressure-correction schemes used for the incompressible Navier-Stokes flow computations. This version is validated on standard te...

  16. Inclusion of a Direct and Inverse Energy-Consistent Hysteresis Model in Dual Magnetostatic Finite Element Formulations

    OpenAIRE

    Jacques, Kevin; Sabariego, Ruth,; Geuzaine, Christophe; GYSELINCK Johan

    2015-01-01

    This paper deals with the implementation of an energy-consistent ferromagnetic hysteresis model in 2D finite element computations. This vector hysteresis model relies on a strong thermodynamic foundation and ensures the closure of minor hysteresis loops. The model accuracy can be increased by controlling the number of intrinsic cell components while parameters can be easily fitted on common material measurements. Here, the native h-based material model is inverted using the Newton-Raphson met...

  17. 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.

  18. Local Interaction Simulation Approach for Fault Detection in Medical Ultrasonic Transducers

    Directory of Open Access Journals (Sweden)

    Z. Hashemiyan

    2015-01-01

    Full Text Available A new approach is proposed for modelling medical ultrasonic transducers operating in air. The method is based on finite elements and the local interaction simulation approach. The latter leads to significant reductions of computational costs. Transmission and reception properties of the transducer are analysed using in-air reverberation patterns. The proposed approach can help to provide earlier detection of transducer faults and their identification, reducing the risk of misdiagnosis due to poor image quality.

  19. Technology trends in high temperature pressure transducers: The impact of micromachining

    Science.gov (United States)

    Mallon, Joseph R., Jr.

    1992-01-01

    This paper discusses the implications of micromachining technology on the development of high temperature pressure transducers. The introduction puts forth the thesis that micromachining will be the technology of choice for the next generation of extended temperature range pressure transducers. The term micromachining is defined, the technology is discussed and examples are presented. Several technologies for high temperature pressure transducers are discussed, including silicon on insulator, capacitive, optical, and vibrating element. Specific conclusions are presented along with recommendations for development of the technology.

  20. 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...

  1. An enzyme logic bioprotonic transducer

    Science.gov (United States)

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

    2015-01-01

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

  2. 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.

  3. Fixture for holding testing transducer

    Science.gov (United States)

    Wagner, Thomas A.; Engel, Herbert P.

    1984-01-01

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

  4. 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...

  5. 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.

  6. Hinged Hydrostatic Transducers.

    Science.gov (United States)

    1984-01-01

    around the elements in such a way that it is void free. A flexible electrode must be applied that integrates the travzducers into a single electrical...conformable and had a moderate area of 100 cm2 . Evaluacion of che various one, L-ao or chree dimensionally connecced ?ZT necvorks has indicaced chat

  7. 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

  8. 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%.

  9. 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.

  10. 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.

  11. 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.

  12. THE CURIOUS CASE OF ELEMENTAL ABUNDANCE DIFFERENCES IN THE DUAL HOT JUPITER HOSTS WASP-94A AND B

    Energy Technology Data Exchange (ETDEWEB)

    Teske, Johanna K. [Carnegie Department of Terrestrial Magnetism, 5241 Broad Branch Road, NW, Washington, DC 20015 (United States); Khanal, Sandhya; Ramírez, Ivan, E-mail: jteske@carnegiescience.edu [McDonald Observatory and Department of Astronomy, University of Texas at Austin, 2515 Speedway, Stop C1402, Austin, TX 78712-1205 (United States)

    2016-03-01

    Binary stars provide an ideal laboratory for investigating the potential effects of planet formation on stellar composition. Assuming that the stars formed in the same environment/from the same material, any compositional anomalies between binary components might indicate differences in how material was sequestered in planets, or accreted by the star in the process of planet formation. We present here a study of the elemental abundance differences between WASP-94A and B, a pair of stars that each host a hot Jupiter exoplanet. The two stars are very similar in spectral type (F8 and F9), and their ∼2700 au separation suggests that their protoplanetary disks were likely not influenced by stellar interactions, but WASP-94Ab’s orbit—misaligned with the host star spin axis and likely retrograde—points toward a dynamically active formation mechanism, perhaps different from that of WASP-94Bb, which is not misaligned and has a nearly circular orbit. Based on our high-quality spectra and strictly relative abundance analysis, we detect a depletion of volatiles (∼−0.02 dex, on average) and enhancement of refractories (∼0.01 dex) in WASP-94A relative to B (standard errors are ∼0.005 dex). This is different from every other published case of binary host star abundances, in which either no significant abundance differences are reported or there is some degree of enhancement in all elements, including volatiles. Several scenarios that may explain the abundance trend are discussed, but none can be definitively accepted or rejected. Additional high-contrast imaging observations to search for companions that may be dynamically affecting the system, as well as a larger sample of binary host star studies, are needed to better understand the curious abundance trends we observe in WASP-94A and B.

  13. Multilayer Array Transducer for Nonlinear Ultrasound Imaging

    Science.gov (United States)

    Owen, Neil R.; Kaczkowski, Peter J.; Li, Tong; Gross, Dan; Postlewait, Steven M.; Curra, Francesco P.

    2011-09-01

    The properties of nonlinear acoustic wave propagation are known to be able to improve the resolution of ultrasound imaging, and could be used to dynamically estimate the physical properties of tissue. However, transducers capable of launching a wave that becomes nonlinear through propagation do not typically have the necessary bandwidth to detect the higher harmonics. Here we present the design and characterization of a novel multilayer transducer for high intensity transmit and broadband receive. The transmit layer was made from a narrow-band, high-power piezoceramic (PZT), with nominal frequency of 2.0 MHz, that was diced into an array of 32 elements. Each element was 0.300 mm wide and 6.3 mm in elevation, and with a pitch of 0.400 mm the overall aperture width was 12.7 mm. A quarter-wave matching layer was attached to the PZT substrate to improve transmit efficiency and bandwidth. The overlaid receive layer was made from polyvinylidene fluoride (PVDF) that had gold metalization on one side. A custom two-sided flex circuit routed electrical connections to the PZT elements and patterned the PVDF elements; the PZT and PVDF elements had identical apertures. A low viscosity and electrically nonconductive epoxy was used for all adhesion layers. Characterization of electrical parameters and acoustic output were performed per standard methods, where transmit and receive events were driven by a software-controlled ultrasound engine. Echo data, collected from ex vivo tissue and digitized at 45 MS/s, exhibited frequency content up to the 4th harmonic of the 2 MHz transmit frequency.

  14. 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.

  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. First measurements on a novel type of optical micro-machined ultrasound transducer (OMUT)

    NARCIS (Netherlands)

    Leinders, S.M.; Dongen, K.W.A. van; Jong, N. de; Verweij, M.D.; Westerveld, W.J.; Urbach, H.P.; Neer, P.L.M.J. van; Pozo Torres, J.M.

    2014-01-01

    Several types of ultrasound sensors have been developed and are used in the field of medical imaging. Conventional transducers are made of piezo-electric material and show good practical performance. However, when the piezo-electric elements need to be small (below 100 μm × 100 μm), these transducer

  17. First measurements on a novel type of optical micro-machined ultrasound transducer (OMUT)

    NARCIS (Netherlands)

    Leinders, S.M.; Dongen, K.W.A. van; Jong, N. de; Verweij, M.D.; Westerveld, W.J.; Urbach, H.P.; Neer, P.L.M.J. van; Pozo Torres, J.M.

    2014-01-01

    Several types of ultrasound sensors have been developed and are used in the field of medical imaging. Conventional transducers are made of piezo-electric material and show good practical performance. However, when the piezo-electric elements need to be small (below 100 μm × 100 μm), these transducer

  18. design and implementation of a microcontroller based dual axis ...

    African Journals Online (AJOL)

    user

    DESIGN AND IMPLEMENTATION OF A MICROCONTROLLER BASED. DUAL AXIS .... Output mechanical transducer (Servo Motor). 2.1 Power .... Fig 5: Servo Motor Algorithm. Figure 6: .... Optimization and Performance Evaluation of a Single.

  19. 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

  20. Auto-positioning ultrasonic transducer system

    Science.gov (United States)

    Buchanan, Randy K. (Inventor)

    2010-01-01

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

  1. Extension of the mixed dual finite element method to the solution of the SPN transport equation in 2D unstructured geometries composed by arbitrary quadrilaterals

    Energy Technology Data Exchange (ETDEWEB)

    Lautard, J.J.; Flumiani, T. [CEA Saclay, Direction de l' Energie Nucleaire (DEN/SERMA), Service d' Etude des Reacteurs et de Modelisations Avancees, 91 - Gif sur Yvette (France)

    2003-07-01

    The mixed dual finite element method is usually used for the resolution of the SPN transport equations (simplified PN equations) in 3D homogenized geometries (composed by homogenized rectangles or hexagons). This method produces fast results with little memory requirements. We have extended the previous method to the treatment of unstructured geometries composed by quadrilaterals (for the moment limited to 2D), allowing us to treat geometries where fuel pins are exactly represented. The iterative resolution of the resulting matrix system is a generalization of the one already developed for the cartesian and the hexagonal geometries. In order to illustrate and to show the efficiency of this method, results on the NEA-C5G7-MOX benchmark are given. The previous benchmark has been extended for the hexagonal geometry and we provide here some results. This method is a first step towards the treatment of pin by pin core calculations without homogenization. The present solver is a prototype. It shows the efficiency of the method and it has to be extended to 3D calculations as well as to exact transport calculations. We also intend to extend the method to the treatment of unstructured geometries composed by quadrilaterals with curved edges (sectors of a circle).The iterative algorithm has yet to be accelerated using multigrid techniques through a coupling with the present homogenized solver (MINOS). In the future, it will be included in the next generation neutronic toolbox DESCARTES currently under development.

  2. Performance of transducers with segmented piezoelectric stacks using materials with high electromechanical coupling coefficient

    CERN Document Server

    Thompson, Stephen C; Markley, Douglas C

    2013-01-01

    Underwater acoustic transducers often include a stack of thickness polarized piezoelectric material pieces of alternating polarity interspersed with electrodes, bonded together and electrically connected in parallel. The stack is normally much shorter than a quarter wavelength at the fundamental resonance frequency, so that the mechanical behavior of the transducer is not affected by the segmentation. When the transducer bandwidth is less than a half octave, as has conventionally been the case, stack segmentation has no significant effect on the mechanical behavior of the device. However, when a high coupling coefficient material such as PMN-PT is used to achieve a wider bandwidth, the difference between a segmented stack and a similar piezoelectric section with electrodes only at the two ends can be significant. This paper investigates the effects of stack segmentation on the performance of wideband underwater acoustic transducers, particularly tonpilz transducer elements. Included is discussion of transduce...

  3. Advantage analysis of PMN-PT material for free-flooded ring transducers

    Institute of Scientific and Technical Information of China (English)

    He Zheng-Yao; Ma Yuan-Liang

    2011-01-01

    The acoustic radiation characteristics of free-flooded ring transducers made of PZT4 and PMN-PT materials are calculated and compared.First,the theoretical formulae for free-flooded ring transducers are studied.The resonant frequencies of a transducer made of PZT4 and PMN-PT materials are calculated. Then,the transmitting voltage responses of the free-flooded ring transducers are calculated using the finite element method.Finally,the acoustic radiation characteristics of the free-flooded ring transducers are calculated using the boundary element method.The calculated results show that the resonant frequencies of the free-flooded ring transducer made of PMN-PT are greatly reduced compared with those made of PZT4 with the same size.The transmitting voltage response of the transducer made of PMN-PT is much higher than that of the transducer made of PZT4.The calculated 3-dB beamwidth of the acoustic radiated far-field directivity of the free-flooded ring transducer made of PZT4 at the resonant frequency 1900 Hz is 63.6° and that of the transducer made of PMN-PT at the resonant frequency 1000 Hz is 64.6°.The comparison results show that the free-flooded ring transducer made of PMN-PT material has many advantages over that made of PZT4.The PMN-PT is a promising material for improving the performance of free-flooded ring transducers.

  4. Human placenta as a 'dual' biomarker for monitoring fetal and maternal environment with special reference to potentially toxic trace elements. Part 1: physiology, function and sampling of placenta for elemental characterisation.

    Science.gov (United States)

    Iyengar, G V; Rapp, A

    2001-12-03

    Choice of specimen from human subjects for monitoring pollutants proven to be detrimental to human health depends on the criteria chosen, namely real-time monitoring (RTM) or long-term monitoring (LTM). Specimens such as whole blood, urine, saliva and breast milk are commonly used from living subjects for RTM of toxic metals. However, sampling blood requires an invasive procedure. On the other hand, hair (with some limitations), bone (especially for the assessment of bone seeking elements), adipose tissue (mainly for organic pollutants) and liver (for both organic and inorganic toxicants) are used as specimens for LTM. With the exception of hair, generally these specimens are obtained at post-mortem. In context of health-related biomonitoring, placenta as a specimen has not received as much attention as it deserves. It is a unique sample requiring no invasive procedure, and offers possibilities for RTM, in particular as a dual purpose specimen for evaluating the pollutant burden exerted on the mother as well as on the fetus. Obtaining representative samples of placenta for elemental composition studies is a difficult task, because of heterogeneous mix of placental cells and decidual matter tainted with maternal and fetal blood. Therefore, the present sampling practices for placental tissue, and guidelines to safeguard the validity of the sampled material have been reviewed in part 1 with the following conclusions: medico-legal and ethical matters should be properly addressed before collecting the placenta; it is advisable to collect the entire placenta even if it includes the umbilical cord; further preparatory work is to be carried out in a clean laboratory and depends upon the purpose of the investigation; homogenising the entire sample may prove to be technically challenging but this step is crucial to obtain representative samples, handling the entire sample may be unavoidable; and an alternative method of procuring representative samples would require random

  5. 多阵元超声换能器阵列涡轮机全覆盖故障检测研究%Research on Comprehensive Fault Detection of Turbine Engine Based on Ultrasonic Transducer with Multi Array Elements

    Institute of Scientific and Technical Information of China (English)

    高之圣; 王海燕; 张日刚

    2013-01-01

    提出了一种基于多阵元超声换能器阵列的航空涡轮发动机的超声波相控阵故障检测方法,采用面阵列分布设计了36个多阵元的超声换能器阵列,通过多次多方向的检测方法降低虚警概率,一次检测就可全覆盖整个叶片,不用多次检测,提高了检测速度。检测过程中由于有多个超声阵元可以接收到声波,所以检测的增益、信噪比也得到了提高。仿真实验表明,采用新方法检测的对象既可以是整块的平面,又可以覆盖到涡轮叶片中的整个散热管道,检测概率比传统超声故障检测提高了20%以上。%An ultrasonic phased array fault detection method of aviation turbine engine array ultrasound transducer array based, more than 36 ultrasonic transducer array design using area array distribution, detection method by multi direction to reduce the false alarm probability, a test can fully cover the entire leaf, without repeated testing to improve the detec-tion speed. The detection process as a plurality of ultrasound array can receive sound wave, so the gain, signal to noise ratio is improved detection. Simulation results show that, by using object detection method can be the whole plane, and can cover of the turbine blade is the heat pipe, the probability of detection than traditional ultrasonic fault detection in-creased more than 20%.

  6. Application of PMN-32PT Piezoelectric Crystals for Novel Air-coupled Ultrasonic Transducers

    Science.gov (United States)

    Kazys, Rymantas Jonas; Sliteris, Reimondas; Sestoke, Justina

    Due to very high piezoelectric properties of PMN-PT crystals they may significantly improve performance of air-coupled ultrasonic transducers. For these purpose vibrations of PMN-PT rectangular plates and strips were investigated. An air-coupled ultrasonic transducer and array consisting of 8 single piezoelectric strips were designed. Operation of the transducer was simulated by the finite element method using ANSYS Mechanical APDL Product Launcher software. Spatial distributions of displacements inside piezoelectric elements and matching strip were obtained. Experimental investigations were carried out by the laser Doppler vibrometer Polytec OFV-5000 and the Bruel&Kjaer microphone 4138 with the measurement amplifier NEXUS WH 3219. It was found that performance of the ultrasonic transducer with PMN-32PT crystals was a few times better than of a PZT based ultrasonic transducer.

  7. Optimization Design Method for the CMOS-Type Capacitive Micro-Machined Ultrasonic Transducer

    National Research Council Canada - National Science Library

    D Y Chiou; S B Luo; H H Chen

    2011-01-01

    ...) capacitive micro-arrayed ultrasonic transducer (pCMOS-CMUT) is presented. Electromechanical finite element simulations are performed to investigate its operational characteristics, such as the collapse voltage and the resonant frequency...

  8. 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.

  9. The Use of Phononic Crystals to Design Piezoelectric Power Transducers

    Directory of Open Access Journals (Sweden)

    Silvia Ronda

    2017-03-01

    Full Text Available It was recently proposed that the lateral resonances around the working resonance band of ultrasonic piezoelectric sandwich transducers can be stopped by a periodic array of circular holes drilled along the main propagation direction (a phononic crystal. In this work, the performance of different transducer designs made with this procedure is tested using laser vibrometry, electric impedance tests and finite element models (FEM. It is shown that in terms of mechanical vibration amplitude and acoustic efficiency, the best design for physiotherapy applications is when both, the piezoceramic and an aluminum capsule are phononic structures. The procedure described here can be applied to the design of power ultrasonic devices, physiotherapy transducers and other external medical power ultrasound applications where piston-like vibration in a narrow band is required.

  10. 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.

  11. 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.

  12. 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.)

  13. 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.

  14. 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.

  15. Non-bonded ultrasonic transducer

    Science.gov (United States)

    Eoff, J.M.

    1984-07-06

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

  16. Acoustic transducer for acoustic microscopy

    Science.gov (United States)

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

    1990-01-01

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

  17. Vacuum mounting for piezoelectric transducers

    Science.gov (United States)

    Tiede, D. A.

    1977-01-01

    Special housing couples piezoelectric transducers to nonporous surfaces for ultrasonic or acoustic-emission testing. Device, while providing sound isolation on flat or nonflat surfaces, can be attached and detached quickly. Vacuum sealing mechanism eliminates need for permanent or semipermanent bonds, viscous coupling liquids, weights, magnets, tape, or springs ordinarily used.

  18. 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.

  19. Phased annular array transducers for omnidirectional guided wave mode control in isotropic plate like structures

    Science.gov (United States)

    Koduru, Jaya P.; Momeni, Sepandarmaz; Rose, Joseph L.

    2013-12-01

    Ultrasonic guided waves are fast emerging as a reliable tool for continuous structural health monitoring. Their multi-modal nature along with their long range propagation characteristics offer several possibilities for interrogating structures. Transducers commonly used to generate guided waves in structures excite multiple modes at any frequency; their complex scattering and reflection from defects and boundaries often complicates the extraction of useful information. Often it is desirable to control the guided wave modes propagating in a structure to take advantage of their unique properties for different applications. Earlier attempts at guided wave mode control involved developing fixed wavelength linear and annular array transducers. Their only disadvantage is that the transducer is limited to a particular wavelength and a change in wavelength necessitates a change in the transducer. In this paper, we propose the development of an annular array transducer that can generate mode controlled omnidirectional guided waves by independently controlling the amplitude and phase of the array elements. A simplified actuator model that approximates the transducer loading on the structure to a constant pressure load under the array elements is assumed and an optimization problem is set up to compute the excitation voltage and phase of the elements. A five element annular array transducer is designed utilizing 1-3 type piezocomposite materials. The theoretical computations are experimentally verified on an aluminum plate like structure by exciting A0 and S0 guided wave modes.

  20. Reductive dechlorination of TCE by chemical model systems in comparison to dehalogenating bacteria: insights from dual element isotope analysis (13C/12C, 37Cl/35Cl).

    Science.gov (United States)

    Cretnik, Stefan; Thoreson, Kristen A; Bernstein, Anat; Ebert, Karin; Buchner, Daniel; Laskov, Christine; Haderlein, Stefan; Shouakar-Stash, Orfan; Kliegman, Sarah; McNeill, Kristopher; Elsner, Martin

    2013-07-02

    Chloroethenes like trichloroethene (TCE) are prevalent environmental contaminants, which may be degraded through reductive dechlorination. Chemical models such as cobalamine (vitamin B12) and its simplified analogue cobaloxime have served to mimic microbial reductive dechlorination. To test whether in vitro and in vivo mechanisms agree, we combined carbon and chlorine isotope measurements of TCE. Degradation-associated enrichment factors ε(carbon) and ε(chlorine) (i.e., molecular-average isotope effects) were -12.2‰ ± 0.5‰ and -3.6‰ ± 0.1‰ with Geobacter lovleyi strain SZ; -9.1‰ ± 0.6‰ and -2.7‰ ± 0.6‰ with Desulfitobacterium hafniense Y51; -16.1‰ ± 0.9‰ and -4.0‰ ± 0.2‰ with the enzymatic cofactor cobalamin; -21.3‰ ± 0.5‰ and -3.5‰ ± 0.1‰ with cobaloxime. Dual element isotope slopes m = Δδ(13)C/ Δδ(37)Cl ≈ ε(carbon)/ε(chlorine) of TCE showed strong agreement between biotransformations (3.4 to 3.8) and cobalamin (3.9), but differed markedly for cobaloxime (6.1). These results (i) suggest a similar biodegradation mechanism despite different microbial strains, (ii) indicate that transformation with isolated cobalamin resembles in vivo transformation and (iii) suggest a different mechanism with cobaloxime. This model reactant should therefore be used with caution. Our results demonstrate the power of two-dimensional isotope analyses to characterize and distinguish between reaction mechanisms in whole cell experiments and in vitro model systems.

  1. 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.

  2. Concentrations of Radionuclides and Trace Elements in Environmantal Media arond te Dual-Axis Radiographic Hydrodynamic Test Facilit at Los Alamos National Laboratory during 2005

    Energy Technology Data Exchange (ETDEWEB)

    G.J.Gonzales; P.R. Fresquez; C.D.Hathcock; D.C. Keller

    2006-05-15

    The Mitigation Action Plan (MAP) for the Dual-Axis Radiographic Hydrodynamic Test (DARHT) facility at Los Alamos National Laboratory requires that samples of biotic and abiotic media be collected after operations began to determine if there are any human health or environmental impacts. The DARHT facility is the Laboratory's principal explosive test facility. To this end, samples of soil and sediment, vegetation, bees, and birds were collected around the facility in 2005 and analyzed for concentrations of {sup 3}H, {sup 137}Cs, {sup 90}Sr, {sup 238}Pu, {sup 239,240}Pu, {sup 241}Am, {sup 234}U, {sup 235}U, {sup 238}U, Ag, As, Ba, Be, Cd, Cr, Cu, Hg, Ni, Pb, Sb, Se, and Tl. Bird populations have also been monitored. Contaminant results, which represent up to six sample years since the start of operations, were compared with (1) baseline statistical reference levels (BSRLs) established over a four-year preoperational period before DARHT facility operations, (2) screening levels (SLs), and (3) regulatory standards. Most radionuclides and trace elements were below BSRLs and those few samples that contained radionuclides and trace elements above BSRLs were below SLs. Concentrations of radionuclides and nonradionuclides in biotic and abiotic media around the DARHT facility do not pose a significant human health hazard. The total number of birds captured and number of species represented were similar in 2003 and 2004, but both of these parameters increased substantially in 2005. Periodic interruption of the scope and schedule identified in the MAP generally should have no impact on meeting the intent of the MAP. The risk of not sampling one of the five media in any given year is that if a significant impact to contaminant levels were to occur there would exist a less complete understanding of the extent of the change to the baseline for these media and to the ecosystem as a whole. Since the MAP is a requirement that was established under the regulatory framework of

  3. Wideband Single Crystal Transducer for Bone Characterization

    Science.gov (United States)

    Sahul, Raffi

    2015-01-01

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

  4. 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...

  5. Input impedance matching of acoustic transducers operating at off-resonant frequencies.

    Science.gov (United States)

    Son, Kyu Tak; Lee, Chin C

    2010-12-01

    The input impedance matching technique of acoustic transducers at off-resonant frequencies is reported. It uses an inherent impedance property of transducers and thus does not need an external electric matching circuit or extra acoustic matching section. The input electrical equivalent circuit includes a radiation component and a dielectric capacitor. The radiation component consists of a radiation resistance and a radiation reactance. The total reactance is the sum of the radiation reactance and the dielectric capacitive reactance. This reactance becomes zero at two frequencies where the impedance is real. The transducer size can be properly chosen so that the impedance at one of the zero-crossing frequencies is close to 50 Ω, the output impedance of signal generators. At this off-resonant operating frequency, the reflection coefficient of the transducer is minimized without using any matching circuit. Other than the size, the impedance can also be fine tuned by adjusting the thickness of material that bonds the transducer plate to the substrates. The acoustic impedance of the substrate and that of the bonding material can also be used as design elements in the transducer structure to achieve better transducer matching. Lead titanate piezoelectric plates were bonded on Lucite, liquid crystal polymer (LCP), and bismuth (Bi) substrates to produce various transducer structures. Their input impedance was simulated using a transducer model and compared with measured values to illustrate the matching principle.

  6. 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.

  7. 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.

  8. 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...... depended, nonlinear and high bias voltage for linearization) must be developed. This paper analyzes a power stage suitable for driving an electrostatic transducer under biasing. Measurement results of a ±400 V prototype amplifier are shown. THD below 1% is reported....

  9. Transducer for harmonic intravascular ultrasound imaging

    NARCIS (Netherlands)

    Vos, Hendrik J.; Frijlink, Martijn E.; Droog, E.J.; Goertz, David E.; Blacquiere, Gerrit; Gisolf, Anton; de Jong, N.; van der Steen, Antonius F.W.

    2005-01-01

    A recent study has shown the feasibility of tissue harmonic imaging (THI) using an intravascular ultrasound (IVUS) transducer. This correspondence describes the design, fabrication, and characterization of a THI-optimized piezoelectric transducer with oval aperture of 0.75 mm by 1 mm. The transducer

  10. 21 CFR 882.1950 - Tremor transducer.

    Science.gov (United States)

    2010-04-01

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

  11. Design and fabrication of liner-arroy ultrasonic transducer using KLM and FEM simulation for non-destructive testing

    Energy Technology Data Exchange (ETDEWEB)

    Park, Chan Yuk; Sung, Jin Ho; Jeong, Jong Seob [Dept. of Medical Biotechnology, Dongguk University Biomedi Campus, Goyang (Korea, Republic of)

    2015-04-15

    In this paper, a linear-array transducer capable of overcoming the faults of a single element and phased array transducers with convex shape for non-destructive ultrasonic testing was designed and fabricated. A 5.5 MHz linear-array transducer was designed using the PiezoCAD program based on the KLM analysis and the PZFlex program based on the FEM analysis. A 2-2 composite structure was employed to achieve broad-band characteristics. A 128 element linear-array transducer was fabricated and its performance was compared with the simulation results. The center frequency of the fabricated transducer was 5.5 Mhzand the -6 dB frequency bandwidth was 70 %. Thus, we expect that the designed transducer can provide an effective inner image of the test material during non-destructive ultrasonic testing.

  12. Time delay controlled annular array transducers for omnidirectional guided wave mode control in plate like structures

    Science.gov (United States)

    Koduru, Jaya P.; Rose, Joseph L.

    2014-10-01

    Guided waves in plate like structures offer several modes with unique characteristics that can be taken advantage for nondestructive inspection applications. Conditions relating to the structure under inspection like the surrounding media, liquid loading, coatings etc require the use of special modes for successful inspection. Therefore, transducers that can excite mode controlled guided waves are essential for defect detection and discrimination in structures. Array transducers with annular elements can generate omnidirectional guided waves in plate like structures. However, the wave modes excited are limited to a particular wavelength governed by the element spacing. This limitation on the annular array transducers can be overcome by controlling the phase at each element relative to one another. In this work, annular array transducer construction techniques are theoretically examined and the optimum phase delays between the annular elements to excite a desired guided wave mode are calculated. A five element comb type annular array transducer is fabricated utilizing 1-3 type piezocomposite material. The mode control capability of the transducer is experimentally verified by selectively exciting the A0 and S0 guided wave modes in an aluminum plate like structure.

  13. Self-Calibrating Pressure Transducer

    Science.gov (United States)

    Lueck, Dale E. (Inventor)

    2006-01-01

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

  14. 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...

  15. Metrological analysis of a virtual flowmeter-based transducer for cryogenic helium

    Energy Technology Data Exchange (ETDEWEB)

    Arpaia, P., E-mail: pasquale.arpaia@unina.it [Department of Electrical Engineering and Information Technology, University of Napoli Federico II, Naples (Italy); Technology Department, European Organization for Nuclear Research (CERN), Geneva (Switzerland); Girone, M., E-mail: mario.girone@cern.ch [Technology Department, European Organization for Nuclear Research (CERN), Geneva (Switzerland); Department of Engineering, University of Sannio, Benevento (Italy); Liccardo, A., E-mail: annalisa.liccardo@unina.it [Department of Electrical Engineering and Information Technology, University of Napoli Federico II, Naples (Italy); Pezzetti, M., E-mail: marco.pezzetti@cern.ch [Technology Department, European Organization for Nuclear Research (CERN), Geneva (Switzerland); Piccinelli, F., E-mail: fabio.piccinelli@cern.ch [Department of Mechanical Engineering, University of Brescia, Brescia (Italy)

    2015-12-15

    The metrological performance of a virtual flowmeter-based transducer for monitoring helium under cryogenic conditions is assessed. At this aim, an uncertainty model of the transducer, mainly based on a valve model, exploiting finite-element approach, and a virtual flowmeter model, based on the Sereg-Schlumberger method, are presented. The models are validated experimentally on a case study for helium monitoring in cryogenic systems at the European Organization for Nuclear Research (CERN). The impact of uncertainty sources on the transducer metrological performance is assessed by a sensitivity analysis, based on statistical experiment design and analysis of variance. In this way, the uncertainty sources most influencing metrological performance of the transducer are singled out over the input range as a whole, at varying operating and setting conditions. This analysis turns out to be important for CERN cryogenics operation because the metrological design of the transducer is validated, and its components and working conditions with critical specifications for future improvements are identified.

  16. Modeling transducer impulse responses for predicting calibrated pressure pulses with the ultrasound simulation program Field II

    DEFF Research Database (Denmark)

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

    2010-01-01

    FIELD II is a simulation software capable of predicting the field pressure in front of transducers having any complicated geometry. A calibrated prediction with this program is, however, dependent on an exact voltage-to-surface acceleration impulse response of the transducer. Such impulse response...... is not calculated by FIELD II. This work investigates the usability of combining a one-dimensional multilayer transducer modeling principle with the FIELD II software. Multilayer here refers to a transducer composed of several material layers. Measurements of pressure and current from Pz27 piezoceramic disks...... as well as pressure and intensity measurements in front of a 128 element commercial convex medical transducer are compared to the simulations. Results show that the models can predict the pressure from the piezoceramic disks with a root mean square (rms) error of 11.2% to 36.2% with a 2 dB amplitude...

  17. Metrological analysis of a virtual flowmeter-based transducer for cryogenic helium.

    Science.gov (United States)

    Arpaia, P; Girone, M; Liccardo, A; Pezzetti, M; Piccinelli, F

    2015-12-01

    The metrological performance of a virtual flowmeter-based transducer for monitoring helium under cryogenic conditions is assessed. At this aim, an uncertainty model of the transducer, mainly based on a valve model, exploiting finite-element approach, and a virtual flowmeter model, based on the Sereg-Schlumberger method, are presented. The models are validated experimentally on a case study for helium monitoring in cryogenic systems at the European Organization for Nuclear Research (CERN). The impact of uncertainty sources on the transducer metrological performance is assessed by a sensitivity analysis, based on statistical experiment design and analysis of variance. In this way, the uncertainty sources most influencing metrological performance of the transducer are singled out over the input range as a whole, at varying operating and setting conditions. This analysis turns out to be important for CERN cryogenics operation because the metrological design of the transducer is validated, and its components and working conditions with critical specifications for future improvements are identified.

  18. Note: Decoupling design for high frequency piezoelectric ultrasonic transducers with their clamping connections

    Energy Technology Data Exchange (ETDEWEB)

    Wang, F. J., E-mail: wangfujun@tju.edu.cn; Liang, C. M.; Tian, Y. L.; Zhao, X. Y.; Zhang, D. W. [Tianjin Key Laboratory of Equipment Design and Manufacturing Technology, School of Mechanical Engineering, Tianjin University, Tianjin 300072 (China); Zhang, H. J. [Tianjin Key Laboratory of Modern Mechatronics Equipment Technology, School of Mechanical Engineering, Tianjin Polytechnic University, Tianjin 300387 (China)

    2015-12-15

    This work presents the flexure-mechanism based decoupling design between high frequency piezoelectric ultrasonic transducers and their clamping connections to improve ultrasonic energy transmission efficiency. The ring, prismatic beam, and circular notched hinge based flanges were presented, and the crucial geometric dimensions of the transducers with the flexure decoupling flanges were determined. Finite element analysis (FEA) was carried out to investigate the dynamic characteristics of the transducers. Finally, experiments were conducted to examine and verify the effects of the proposed decoupling flanges. FEA and experimental results show that smaller frequency deviations and larger tip displacement amplitudes have been achieved by using the transducers with the flexure flanges compared with the transducer with a rigid ring-type flange, and thus the ultrasonic transmission efficiency can be improved through the flexure flanges.

  19. 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 ...

  20. LAVA Pressure Transducer Trade Study

    Science.gov (United States)

    Oltman, Samuel B.

    2016-01-01

    The Regolith and Environment Science and Oxygen and Lunar Volatile Extraction (RESOLVE) payload will transport the (LAVA) subsystem to hydrogen-rich locations on the moon supporting NASA's in-situ resource utilization (ISRU) programs. There, the LAVA subsystem will analyze volatiles that evolve from heated regolith samples in order to quantify how much water is present. To do this, the system needs resilient pressure transducers (PTs) to calculate the moles in the gas samples. The PT trade study includes a comparison of newly-procured models to a baseline unit with prior flight history in order to determine the PT model with the best survivability in flight-forward conditions.

  1. 稀土Ⅳ型弯张换能器研究%Research of a Class Ⅳ rare-earth flextensional transducer

    Institute of Scientific and Technical Information of China (English)

    李宽; 蓝宇

    2015-01-01

    Ⅳ型弯张换能器低频发射时具有尺寸小、重量轻的特点,是一种常用的水下低频大功率声源.稀土超磁致伸缩材料相较于压电陶瓷拥有更大的应变量和能量密度,并且杨氏模量较小,可以有效降低换能器谐振频率.利用稀土超磁致伸缩材料作为激励材料,设计了一种低频IV型弯张换能器,对其静态磁场和动态磁场进行了分析,构建出双棒式磁路,并使用有限元分析软件进行了换能器的结构建模与计算.根据计算结果制作了稀土IV型弯张换能器样机,测试结果表明所设计的换能器与仿真结果吻合较好,水中谐振频率为370 Hz,最大声源级为196 dB,能够实现低频、大功率发射.%Class Ⅳ flextensional transducer with features of small size and light weight is a common underwater low frequency and high power source. Compared to piezoelectric ceramic, the rare-earth magnetostrictive material has larger strain and energy density, and lower young's modulus, which can effectively reduce the resonant frequency of the transducer. A low frequency IV flextensional transducer driven by using rare-earth magnetostrictive material is designed. Through the analyses of static and dynamic magnetic fields, a magnetic circuit structure of dual rods type is built, and the transducer is modeled and calculated with finite element software. Based on the calculation results, a Class IV flex-tensional transducer is manufactured, and the simulation and experimental results are in good agreement. It is shown that the transducer is characterized by low frequency and high power, which means that the resonant frequency in water is 370 Hz, and the sound source level achieves 196 dB.

  2. Mechanical Pre Stressing a Transducer through a Negative DC Biasing Field

    Science.gov (United States)

    2017-04-21

    interesting concept but would not work under high-drive conditions. 17 (18 blank) BIBLIOGRAPHY Butler, S.C., “MLTRT Element FEA Dynamic Stress ...NUWC-NPT Technical Report 12,224 21 April 2017 Mechanical Pre- Stressing a Transducer through a Negative DC Biasing Field Stephen C...TITLE AND SUBTITLE Mechanical Pre- Stressing a Transducer through a Negative DC Biasing Field 5a. CONTRACT NUMBER 5b. GRANT NUMBER 5c

  3. Fabrication of dielectric elastomer stack transducers (DEST) by liquid deposition modeling

    Science.gov (United States)

    Klug, Florian; Solano-Arana, Susana; Mößinger, Holger; Förster-Zügel, Florentine; Schlaak, Helmut F.

    2017-04-01

    Established fabrication methods for dielectric elastomer stack transducers (DEST) are mostly based on twodimensional thin-film technology. Because of this, DEST are based on simple two-dimensionally structured shapes. For certain applications, like valves or Braille displays, these structures are suited well enough. However, a more flexible fabrication method allows for more complex actuator designs, which would otherwise require extra processing steps. Fabrication methods with the possibility of three-dimensional structuring allow e.g. the integration of electrical connections, cavities, channels, sensor and other structural elements during the fabrication. This opens up new applications, as well as the opportunity for faster prototype production of individually designed DEST for a given application. In this work, a manufacturing system allowing three dimensional structuring is described. It enables the production of multilayer and three-dimensional structured DEST by liquid deposition modelling. The system is based on a custom made dual extruder, connected to a commercial threeaxis positioning system. It allows a computer controlled liquid deposition of two materials. After tuning the manufacturing parameters the production of thin layers with at thickness of less than 50 μm, as well as stacking electrode and dielectric materials is feasible. With this setup a first DEST with dielectric layer thickness less than 50 μm is build successfully and its performance is evaluated.

  4. A parametric study of ultrasonic beam profiles for a linear phased array transducer.

    Science.gov (United States)

    Lee, J H; Choi, S W

    2000-01-01

    A numerical simulation model is presented to investigate the influences of design parameters of linear phased array transducers on beam focusing and steering performance. The characteristic of ultrasonic beam profiles has been simulated on the basis of the Huygen's superposition principle. For the simulation, a linear phased array is considered as the composition of finite number of elements separated by equidistance. Individual elements are considered as two-dimensional point sources. The waves generated from piezoelectric elements are considered as simplified transient ultrasonic waves that are constructed with the cosine function enveloped with a Hanning window. The characteristic of ultrasonic wave propagation into a medium from the phased array transducer is described. The effects of the number, the interelement spacing, steering angle, the focal length, and frequency bandwidth of the piezoelectric elements on beam directivity and ultrasonic pressure field in a linear phased array transducer are systematically discussed.

  5. Development of high frequency annular array ultrasound transducers

    Science.gov (United States)

    Gottlieb, Emanuel John

    The advantage of ultrasonic annular arrays over conventional single element transducers has been in the ability to transmit focus at multiple points throughout the depth of field, as well as receive dynamic focus. Today, annular, linear and multidimensional array imaging systems are not commercially available at frequencies greater than 20 MHz. The fabrication technology used to develop a high frequency (>50 MHz) annular array transducer is presented. A 9 mum P(VDF-TrFE) film was bonded to gold annuli electrodes on the top layer of a two sided polyimide flexible circuit. Each annulus was separated by a 30 mum kerf and had several electroplated micro vias that connected to electrode traces on the bottom side of the polyimide flexible circuit. The array's performance was evaluated by measuring the electrical impedance, pulse echo response and crosstalk measurement for each element in the array. In order to improve device sensitivity each element was electrically matched to an impedance magnitude of 50 O and 0° phase at resonance. The average round trip insertion loss measured for the array and compensated for diffraction effects was -33.5 dB. The measured average center frequency and bandwidth of an element was 55 MHz and 47 respectively. The measured crosstalk between adjacent elements remained below -29 dB at the center frequency in water. A vertical wire phantom was imaged using a single focus transmit beamformer and dynamic focusing receive beamformer. This image showed a significant improvement in lateral resolution over a range of 9 mm after the dynamic focusing receive algorithm was applied. These results correlated well with predictions from a Field II simulation. After beamforming the minimum lateral resolution (-6 dB) was 108 mum at the focus. Preliminary ultrasound B-mode images of the rabbit eye using this transducer were shown in conjunction with a multi-channel digital beamformer. A feasibility study of designing and fabricating tunable copolymer

  6. Development of a spherically focused phased array transducer for ultrasonic image-guided hyperthermia

    Science.gov (United States)

    Liu, Jingfei; Foiret, Josquin; Stephens, Douglas N.; Le Baron, Olivier; Ferrara, Katherine W.

    2016-07-01

    A 1.5 MHz prolate spheroidal therapeutic array with 128 circular elements was designed to accommodate standard imaging arrays for ultrasonic image-guided hyperthermia. The implementation of this dual-array system integrates real-time therapeutic and imaging functions with a single ultrasound system (Vantage 256, Verasonics). To facilitate applications involving small animal imaging and therapy the array was designed to have a beam depth of field smaller than 3.5 mm and to electronically steer over distances greater than 1 cm in both the axial and lateral directions. In order to achieve the required f number of 0.69, 1-3 piezocomposite modules were mated within the transducer housing. The performance of the prototype array was experimentally evaluated with excellent agreement with numerical simulation. A focal volume (2.70 mm (axial)  ×  0.65 mm (transverse)  ×  0.35 mm (transverse)) defined by the  -6 dB focal intensity was obtained to address the dimensions needed for small animal therapy. An electronic beam steering range defined by the  -3 dB focal peak intensity (17 mm (axial)  ×  14 mm (transverse)  ×  12 mm (transverse)) and  -8 dB lateral grating lobes (24 mm (axial)  ×  18 mm (transverse)  ×  16 mm (transverse)) was achieved. The combined testing of imaging and therapeutic functions confirmed well-controlled local heating generation and imaging in a tissue mimicking phantom. This dual-array implementation offers a practical means to achieve hyperthermia and ablation in small animal models and can be incorporated within protocols for ultrasound-mediated drug delivery.

  7. 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.

  8. 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.

  9. ERROR COMPENSATOR FOR A POSITION TRANSDUCER

    Science.gov (United States)

    Fowler, A.H.

    1962-06-12

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

  10. Air-Coupled Piezoelectric Transducers with Active Polypropylene Foam Matching Layers

    Directory of Open Access Journals (Sweden)

    Tomás E. Gómez Alvarez-Arenas

    2013-05-01

    Full Text Available This work presents the design, construction and characterization of air-coupled piezoelectric transducers using 1–3 connectivity piezocomposite disks with a stack of matching layers being the outer one an active quarter wavelength layer made of polypropylene foam ferroelectret film. This kind of material has shown a stable piezoelectric response together with a very low acoustic impedance (<0.1 MRayl. These features make them a suitable candidate for the dual use or function proposed here: impedance matching layer and active material for air-coupled transduction. The transducer centre frequency is determined by the l/4 resonance of the polypropylene foam ferroelectret film (0.35 MHz, then, the rest of the transducer components (piezocomposite disk and passive intermediate matching layers are all tuned to this frequency. The transducer has been tested in several working modes including pulse-echo and pitch-catch as well as wide and narrow band excitation. The performance of the proposed novel transducer is compared with that of a conventional air-coupled transducers operating in a similar frequency range.

  11. Finite element analysis and comparison between simulation and test for a discal piezoelectric transducer with spiral interdigitated electrodes%螺旋叉指电极式压电圆片换能器的有限元分析与实验比较

    Institute of Scientific and Technical Information of China (English)

    肖广军; 潘成亮; 刘永斌; 潘巧生

    2015-01-01

    螺旋叉指电极式压电圆片换能器可以产生面内扭转运动,具有结构简单、加工方便、性能可靠等优点,可用于超声马达、光学扫描、黏度测量等领域;但表面螺旋叉指电极间陶瓷材料的极化方向变化复杂,给换能器的机电耦合分析和优化设计带来极大的难度。利用坐标变换思想与有限元方法,将压电圆片分割成若干子体,通过极化电场分析确定子体局部坐标系以定义材料参数,从而实现复杂极化情况下压电换能器的耦合仿真分析。利用 ANSYS 有限元软件,优化仿真分析过程,研究了该压电圆片换能器的静态扭转位移径向分布特性和动态导纳频率响应特性,并与实验结果相比较,证实了该方法的可行性和有效性。%A piezoelectric disk with spiral interdigitated electrodes (SIEDs)can produce in-plane torsion with advantages of simple structure,convenient manufacture,and reliable performance,it can be applied in ultrasonic motors, optical scanners,viscometers,and many others.However,because of the complex variation of polarizing direction of piezoceramic material between surfaces SIEDs,great difficulties are brought for electromechanical coupling analysis and optimal design of the transducer.Here,utilizing the idea of coordinate transformation with the aid of the finite element method,the piezoelectric disk was divided into a number of sub-volumes.The material parameters were defined in the local coordinate systems determined with the analysis of polarized electric field.Thus,the coupling simulations of the piezoelectric transducer were achieved under the complex polarization conditions.The simulation processes were optimized with the finite element software ANSYS,the radial distribution of static torsional displacement and the frequency response features of dynamic admittance of the transducer were investigated.Comparing the simulation results with the test ones, the

  12. Finite State Transducers Approximating Hidden Markov Models

    CERN Document Server

    Kempe, A

    1999-01-01

    This paper describes the conversion of a Hidden Markov Model into a sequential transducer that closely approximates the behavior of the stochastic model. This transformation is especially advantageous for part-of-speech tagging because the resulting transducer can be composed with other transducers that encode correction rules for the most frequent tagging errors. The speed of tagging is also improved. The described methods have been implemented and successfully tested on six languages.

  13. 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

  14. Pad-printed thick-film transducers for high-frequency and high-power applications

    Science.gov (United States)

    Wolny, Wanda W.; Ketterling, Jeffrey A.; Levassort, Franck; Lou-Moeller, Rasmus; Filoux, Erwan; Mamou, Jonathan; Silverman, Ronald H.; Lethiecq, Marc

    2011-03-01

    High-frequency-ultrasound transducers are widely used but are typically based either on planar piezoceramic sections that are lapped down to smaller thicknesses or on piezopolymers that may be deformed into more complex geometries. Piezoceramics then require dicing to obtain arrays or can be fractured into spherical geometries to achieve focusing. Piezopolymers are not as efficient for very small element sizes and are normally available only in discrete thicknesses. Thick-film (TF) transducers provide a means of overcoming these limits because the piezoelectric film is deposited with the required thickness, size and geometry, thus avoiding any subsequent machining. Thick-film transducers offer the potential of a wide range of geometries such as single-elements and annular or linear arrays. Here, a single-element focused transducer was developed using a piezoceramic composition adapted to high-power operation which is commonly used at standard MHz frequencies. After fabrication, the transducer was characterized. Using specific transmit-receive electronics and a water tank adapted to high-frequency devices, the transducer was excited using a short pulse to evaluate its bandwidth and imaging capabilities. Finally, it was excited by a one-period sine wave using several power levels to evaluate its capacity to produce high-intensity focused ultrasound at frequencies over 20 MHz.

  15. Dual-/tri-apodization techniques for high frequency ultrasound imaging: a simulation study.

    Science.gov (United States)

    Sung, Jin Ho; Jeong, Jong Seob

    2014-10-11

    In the ultrasound B-mode (Brightness-mode) imaging, high side-lobe level reduces contrast to noise ratio (CNR). A linear apodization scheme by using the window function can suppress the side-lobe level while the main-lobe width is increased resulting in degraded lateral resolution. In order to reduce the side-lobe level without sacrificing the main-lobe width, a non-linear apodization method has been suggested. In this paper, we computationally evaluated the performance of the non-linear apodization method such as dual-/tri-apodization focusing on the high frequency ultrasound image. The rectangular, Dolph-Chebyshev, and Kaiser window functions were employed to implement dual-/tri-apodization algorithms. The point and cyst target simulations were conducted by using a dedicated ultrasound simulation tool called Field-II. The center frequency of the simulated linear array transducer was 40 MHz and the total number of elements was 128. The performance of dual-/tri-apodization was compared with that of the rectangular window function focusing on the side-lobe level and the main-lobe widths (at -6 dB and -35 dB). In the point target simulation, the main-lobe widths of the dual-/tri-apodization were very similar to that of the rectangular window, and the side-lobe levels of the dual-/tri-apodization were more suppressed by 9~10 dB. In the cyst target simulation, CNR values of the dual-/tri-apodization were improved by 41% and 51%, respectively. The performance of the non-linear apodization was numerically investigated. In comparison with the rectangular window function, the non-linear apodization method such as dual- and tri-apodization had low side-lobe level without sacrificing the main-lobe width. Thus, it can be a potential way to increase CNR maintaining the main-lobe width in the high frequency ultrasound imaging.

  16. Transducers in medical ultrasound: Part Three. Transducer applications in echocardiology.

    Science.gov (United States)

    Lancée, C T; Daigle, R; Sahn, D J; Thijssen, J M

    1985-09-01

    A comparison is made between phased arrays and mechanical sector scanners in transcutaneous echocardiographic applications. Aspects such as contact area, beam control, side lobes, grating lobes and image quality are discussed in the context of transducer frequency. The incorporation of simultaneous acquisition of Doppler velocity information and display of M-mode signals is considered. Transoesophageal and intraoperative scanning systems for cardiology are also compared, in particular linear arrays, phased arrays and mechanical scanners, and their advantages and disadvantages in relation to the above mentioned aspects are discussed. The general conclusion is that electronic sector scanners may have a considerably improved cost/benefit ratio in the near future and thereby will become the leading systems for echocardiography.

  17. Structural Diagnostics of CFRP Composite Aircraft Components by Ultrasonic Guided Waves and Built-In Piezoelectric Transducers

    Energy Technology Data Exchange (ETDEWEB)

    Matt, Howard M. [Univ. of California, San Diego, CA (United States)

    2006-01-01

    To monitor in-flight damage and reduce life-cycle costs associated with CFRP composite aircraft, an autonomous built-in structural health monitoring (SHM) system is preferred over conventional maintenance routines and schedules. This thesis investigates the use of ultrasonic guided waves and piezoelectric transducers for the identification and localization of damage/defects occurring within critical components of CFRP composite aircraft wings, mainly the wing skin-to-spar joints. The guided wave approach for structural diagnostics was demonstrated by the dual application of active and passive monitoring techniques. For active interrogation, the guided wave propagation problem was initially studied numerically by a semi-analytical finite element method, which accounts for viscoelastic damping, in order to identify ideal mode-frequency combinations sensitive to damage occurring within CFRP bonded joints. Active guided wave tests across three representative wing skin-to-spar joints at ambient temperature were then conducted using attached Macro Fiber Composite (MFC) transducers. Results from these experiments demonstrate the importance of intelligent feature extraction for improving the sensitivity to damage. To address the widely neglected effects of temperature on guided wave base damage identification, analytical and experimental analyses were performed to characterize the influence of temperature on guided wave signal features. In addition, statistically-robust detection of simulated damage in a CFRP bonded joint was successfully achieved under changing temperature conditions through a dimensionally-low, multivariate statistical outlier analysis. The response of piezoceramic patches and MFC transducers to ultrasonic Rayleigh and Lamb wave fields was analytically derived and experimentally validated. This theory is useful for designing sensors which possess optimal sensitivity toward a given mode-frequency combination or for predicting the frequency dependent

  18. 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

  19. 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

  20. 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.

  1. 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...

  2. 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...

  3. Characterization of Ultrasonic Transducers. Measurement report

    DEFF Research Database (Denmark)

    Wilhjelm, Jens Erik

    1996-01-01

    This report contains the first results of a field measurement program for characterizing ultrasonic transducers in use at the Department. Specifically, a number of Panametrics Inc, transducers are characterized by using a 0.1 mm point scatterer as target, which is moved in front of the transdcuer....

  4. 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

  5. Design and Development of a Pressure Transducer for High Hydrostatic Pressure Measurements up to 200 MPa

    Science.gov (United States)

    Kumar, Anuj; Yadav, Sanjay; Agarwal, Ravinder

    2016-06-01

    A number of pressure transducers, based on strain gauge, capacitance/inductance type, frequency resonators, are commercially available and are being used for sensing and producing an electrical output proportional to applied pressure. These sensors have their own advantages and limitations due to operational ease, measurement uncertainty and the costs. Strain gauge type transducers are now well established devices for accurate and precise measurement of pressure within measurement uncertainty up to 0.1 % of full scale. In the present research work, an indigenous strain gauge pressure transducer has been designed, developed, tested and calibrated for pressure measurement up to 200 MPa. The measurement uncertainty estimated using the pressure transducer was found better than 0.1 % of full scale. This transducer was developed using four foil type strain gauges, bonded, two in axial direction while other two in radial direction, to the controlled stress zones of a tubular maraging steel active cylinder working also as diaphragm. The strain gages were then connected to a Wheatstone bridge arrangement to measure stress generated strains. The pressure was applied through matching connector designed in the same tubular transducer active element. The threaded unique design in a single piece through collar, ferule and tubing arrangement provides leak proof pressure connections with external devices without using additional seals. The calibration and performance checking of the pressure transducer was carried out using dead weight type national pressure standard using the internationally accepted calibration procedure.

  6. High performance relaxor-based ferroelectric single crystals for ultrasonic transducer applications.

    Science.gov (United States)

    Chen, Yan; Lam, Kwok-Ho; Zhou, Dan; Yue, Qingwen; Yu, Yanxiong; Wu, Jinchuan; Qiu, Weibao; Sun, Lei; Zhang, Chao; Luo, Haosu; Chan, Helen L W; Dai, Jiyan

    2014-07-29

    Relaxor-based ferroelectric single crystals Pb(Mg1/3Nb2/3)O3-PbTiO3 (PMN-PT) have drawn much attention in the ferroelectric field because of their excellent piezoelectric properties and high electromechanical coupling coefficients (d33~2000 pC/N, kt~60%) near the morphotropic phase boundary (MPB). Ternary Pb(In1/2Nb1/2)O3-Pb(Mg1/3Nb2/3)O3-PbTiO3 (PIN-PMN-PT) single crystals also possess outstanding performance comparable with PMN-PT single crystals, but have higher phase transition temperatures (rhombohedral to tetragonal Trt, and tetragonal to cubic Tc) and larger coercive field Ec. Therefore, these relaxor-based single crystals have been extensively employed for ultrasonic transducer applications. In this paper, an overview of our work and perspectives on using PMN-PT and PIN-PMN-PT single crystals for ultrasonic transducer applications is presented. Various types of single-element ultrasonic transducers, including endoscopic transducers, intravascular transducers, high-frequency and high-temperature transducers fabricated using the PMN-PT and PIN-PMN-PT crystals and their 2-2 and 1-3 composites are reported. Besides, the fabrication and characterization of the array transducers, such as phased array, cylindrical shaped linear array, high-temperature linear array, radial endoscopic array, and annular array, are also addressed.

  7. High Performance Relaxor-Based Ferroelectric Single Crystals for Ultrasonic Transducer Applications

    Directory of Open Access Journals (Sweden)

    Yan Chen

    2014-07-01

    Full Text Available Relaxor-based ferroelectric single crystals Pb(Mg1/3Nb2/3O3-PbTiO3 (PMN-PT have drawn much attention in the ferroelectric field because of their excellent piezoelectric properties and high electromechanical coupling coefficients (d33~2000 pC/N, kt~60% near the morphotropic phase boundary (MPB. Ternary Pb(In1/2Nb1/2O3-Pb(Mg1/3Nb2/3O3-PbTiO3 (PIN-PMN-PT single crystals also possess outstanding performance comparable with PMN-PT single crystals, but have higher phase transition temperatures (rhombohedral to tetragonal Trt, and tetragonal to cubic Tc and larger coercive field Ec. Therefore, these relaxor-based single crystals have been extensively employed for ultrasonic transducer applications. In this paper, an overview of our work and perspectives on using PMN-PT and PIN-PMN-PT single crystals for ultrasonic transducer applications is presented. Various types of single-element ultrasonic transducers, including endoscopic transducers, intravascular transducers, high-frequency and high-temperature transducers fabricated using the PMN-PT and PIN-PMN-PT crystals and their 2-2 and 1-3 composites are reported. Besides, the fabrication and characterization of the array transducers, such as phased array, cylindrical shaped linear array, high-temperature linear array, radial endoscopic array, and annular array, are also addressed.

  8. Design and Development of a Pressure Transducer for High Hydrostatic Pressure Measurements up to 200 MPa

    Science.gov (United States)

    Kumar, Anuj; Yadav, Sanjay; Agarwal, Ravinder

    2017-08-01

    A number of pressure transducers, based on strain gauge, capacitance/inductance type, frequency resonators, are commercially available and are being used for sensing and producing an electrical output proportional to applied pressure. These sensors have their own advantages and limitations due to operational ease, measurement uncertainty and the costs. Strain gauge type transducers are now well established devices for accurate and precise measurement of pressure within measurement uncertainty up to 0.1 % of full scale. In the present research work, an indigenous strain gauge pressure transducer has been designed, developed, tested and calibrated for pressure measurement up to 200 MPa. The measurement uncertainty estimated using the pressure transducer was found better than 0.1 % of full scale. This transducer was developed using four foil type strain gauges, bonded, two in axial direction while other two in radial direction, to the controlled stress zones of a tubular maraging steel active cylinder working also as diaphragm. The strain gages were then connected to a Wheatstone bridge arrangement to measure stress generated strains. The pressure was applied through matching connector designed in the same tubular transducer active element. The threaded unique design in a single piece through collar, ferule and tubing arrangement provides leak proof pressure connections with external devices without using additional seals. The calibration and performance checking of the pressure transducer was carried out using dead weight type national pressure standard using the internationally accepted calibration procedure.

  9. Air-Coupled Low Frequency Ultrasonic Transducers and Arrays with PMN-32%PT Piezoelectric Crystals

    Directory of Open Access Journals (Sweden)

    Rymantas J. Kazys

    2017-01-01

    Full Text Available Air-coupled ultrasonic techniques are being increasingly used for material characterization, non-destructive evaluation of composite materials using guided waves as well as for distance measurements. Application of those techniques is mainly limited by the big losses of ultrasonic signals due to attenuation and mismatch of the acoustic impedances of ultrasonic transducers and air. One of the ways to solve this problem is by application of novel more efficient piezoelectric materials like lead magnesium niobate-lead titanate (PMN-PT type crystals. The objective of this research was the development and investigation of low frequency (<50 kHz wide band air-coupled ultrasonic transducers and arrays with an improved performance using PMN-32%PT crystals. Results of finite element modelling and experimental investigations of the developed transducers and arrays are presented. For improvement of the performance strip-like matching elements made of low acoustic impedance, materials such as polystyrene foams were applied. It allowed to achieve transduction losses for one single element transducer −11.4 dB, what is better than of commercially available air-coupled ultrasonic transducers. Theoretical and experimental investigations of the acoustic fields radiated by the eight element ultrasonic array demonstrated not only a good performance of the array in a pulse mode, but also very good possibilities to electronically focus and steer the ultrasonic beam in space.

  10. Air-Coupled Low Frequency Ultrasonic Transducers and Arrays with PMN-32%PT Piezoelectric Crystals

    Science.gov (United States)

    Kazys, Rymantas J.; Sliteris, Reimondas; Sestoke, Justina

    2017-01-01

    Air-coupled ultrasonic techniques are being increasingly used for material characterization, non-destructive evaluation of composite materials using guided waves as well as for distance measurements. Application of those techniques is mainly limited by the big losses of ultrasonic signals due to attenuation and mismatch of the acoustic impedances of ultrasonic transducers and air. One of the ways to solve this problem is by application of novel more efficient piezoelectric materials like lead magnesium niobate-lead titanate (PMN-PT) type crystals. The objective of this research was the development and investigation of low frequency (<50 kHz) wide band air-coupled ultrasonic transducers and arrays with an improved performance using PMN-32%PT crystals. Results of finite element modelling and experimental investigations of the developed transducers and arrays are presented. For improvement of the performance strip-like matching elements made of low acoustic impedance, materials such as polystyrene foams were applied. It allowed to achieve transduction losses for one single element transducer −11.4 dB, what is better than of commercially available air-coupled ultrasonic transducers. Theoretical and experimental investigations of the acoustic fields radiated by the eight element ultrasonic array demonstrated not only a good performance of the array in a pulse mode, but also very good possibilities to electronically focus and steer the ultrasonic beam in space. PMID:28067807

  11. Air-Coupled Low Frequency Ultrasonic Transducers and Arrays with PMN-32%PT Piezoelectric Crystals.

    Science.gov (United States)

    Kazys, Rymantas J; Sliteris, Reimondas; Sestoke, Justina

    2017-01-06

    Air-coupled ultrasonic techniques are being increasingly used for material characterization, non-destructive evaluation of composite materials using guided waves as well as for distance measurements. Application of those techniques is mainly limited by the big losses of ultrasonic signals due to attenuation and mismatch of the acoustic impedances of ultrasonic transducers and air. One of the ways to solve this problem is by application of novel more efficient piezoelectric materials like lead magnesium niobate-lead titanate (PMN-PT) type crystals. The objective of this research was the development and investigation of low frequency (<50 kHz) wide band air-coupled ultrasonic transducers and arrays with an improved performance using PMN-32%PT crystals. Results of finite element modelling and experimental investigations of the developed transducers and arrays are presented. For improvement of the performance strip-like matching elements made of low acoustic impedance, materials such as polystyrene foams were applied. It allowed to achieve transduction losses for one single element transducer -11.4 dB, what is better than of commercially available air-coupled ultrasonic transducers. Theoretical and experimental investigations of the acoustic fields radiated by the eight element ultrasonic array demonstrated not only a good performance of the array in a pulse mode, but also very good possibilities to electronically focus and steer the ultrasonic beam in space.

  12. Ultrasound transducer selection in clinical imaging practice.

    Science.gov (United States)

    Szabo, Thomas L; Lewin, Peter A

    2013-04-01

    Many types of medical ultrasound transducers are used in clinical practice. They operate at different center frequencies, have different physical dimensions, footprints, and shapes, and provide different image formats. However, little information is available about which transducers are most appropriate for a given application, and the purpose of this article is to address this deficiency. Specifically, the relationship between the transducer, imaging format, and clinical applications is discussed, and systematic selection criteria that allow matching of transducers to specific clinical needs are presented. These criteria include access to and coverage of the region of interest, maximum scan depth, and coverage of essential diagnostic modes required to optimize a patient's diagnosis. Three comprehensive figures organize and summarize the imaging planes, scanning modes, and types of diagnostic transducers to facilitate their selection in clinical diagnosis.

  13. Dual phase evolution

    CERN Document Server

    Green, David G; Abbass, Hussein A

    2014-01-01

    This book explains how dual phase evolution operates in all these settings and provides a detailed treatment of the subject. The authors discuss the theoretical foundations for the theory, how it relates to other phase transition phenomena and its advantages in evolutionary computation and complex adaptive systems. The book provides methods and techniques to use this concept for problem solving. Dual phase evolution concerns systems that evolve via repeated phase shifts in the connectivity of their elements. It occurs in vast range of settings, including natural systems (species evolution, landscape ecology, geomorphology), socio-economic systems (social networks) and in artificial systems (annealing, evolutionary computing).

  14. Ultrasound backscatter microscope using PZT, fine-grain PZT, and single-crystal perovskite transducers

    Science.gov (United States)

    Olbrish, Kenneth D.; Zipparo, Michael J.; Lopath, Patrick D.; Yu, Clarence; Shrout, Thomas R.; Shung, K. Kirk

    1997-04-01

    Higher frequency ultrasound is rapidly becoming an important tool for dermatologic and ophthalmologic imaging. This brings about a need for improvement in single element transducers operating in the frequency range between 40 MHz and 100 MHz. Several piezoelectric materials may yield improved performance over common lead zirconate titanate (PZT) transducers. This study investigated several different materials incorporated into single element transducers. A static ultrasonic backscatter microscope (UBM) was constructed in the laboratory. This system allowed for a comparative testing of the imaging performance of various transducers. B-mode scans made by individual transducers show differences in image resolution. Clinically, these differences may be important to allow finer detail to be observed in a structure. Not only does this work show differences between transducers constructed from various materials, but it does so in an application-based environment. Previously, only a limited number of materials were used in such a system. This study showed results from several materials that had not been demonstrated before.

  15. Improving the Design of Capacitive Micromachined Ultrasonic Transducers Aided with Sensitivity Analysis

    Directory of Open Access Journals (Sweden)

    A Martowicz

    2016-09-01

    Full Text Available The paper presents the results of analysis performed to search for feasible design improvements for capacitive micromachined ultrasonic transducer. Carried out search has been aided with the sensitivity analysis and the application of Response Surface Method. The multiphysics approach has been taken into account in elaborated finite element model of one cell of described transducer in order to include significant physical phenomena present in modelled microdevice. The set of twelve input uncertain and design parameters consists of geometric, material and control properties. The amplitude of dynamic membrane deformation of the transducer has been chosen as studied parameter. The objective of performed study has been defined as the task of finding robust design configurations of the transducer, i.e. characterizing maximal value of deformation amplitude with its minimal variation.

  16. Analysis of the crosstalk in an underwater planar array transducer by the equivalent circuit method

    Science.gov (United States)

    Pyo, Seonghun; Roh, Yongrae

    2017-07-01

    A planar array transducer consists of several transducers arranged on an acoustic window, which causes crosstalk. The crosstalk is a phenomenon in which the acoustic pressure generated by a projector is transferred to adjacent hydrophones through the acoustic window and the transferred pressure generates noise signals in the hydrophones. The performance of the planar array transducer is deteriorated due to this acoustic interaction, which should be minimized for maximum array performance. Analysis of the crosstalk has been carried out with sophisticated numerical methods, which motivated the need to develop a simpler and accurate analysis method. In this work, an equivalent circuit has been developed to analyze the crosstalk level of the planar array transducer, and the validity of the developed method has been verified by comparing the result from the equivalent circuit analysis with that from finite element analysis.

  17. Nondestructive Evaluation of Double Bevel T-Joint by Tandem Array Ultrasonic Transducer

    Science.gov (United States)

    Shirahata, H.; Miki, C.; Yamaguchi, R.

    2003-03-01

    The double bevel T-joint is one of the most fundamental joints of steel bridges. Double bevel T-joint can be seen at beam-column connection of bridge pier. In the Japanese specifications, the welding should be full penetration. However, weld defect of incomplete penetration could be left in the joint due to the lack of quality control in welding. Fatigue cracks can be propagated from the weld defects. The authors developed a tandem array transducer. The tandem array transducer consists of 10 elements aligned in the same direction. Tandem scanning can be simulated by the transducer. Image reconstruction of incomplete penetration by synthetic aperture focusing technique was carried out. The test results showed sufficient detectability of incomplete penetration by the tandem array transducer. Height of incomplete of penetration could be estimated.

  18. Investigations on the use of pneumatic cross-flow nebulizers with dual solution loading including the correction of matrix effects in elemental determinations by inductively coupled plasma optical emission spectrometry

    Energy Technology Data Exchange (ETDEWEB)

    Bauer, Mathieu [Institute for Inorganic and Applied Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, D-20146 Hamburg (Germany); Broekaert, Jose A.C. [Institute for Inorganic and Applied Chemistry, University of Hamburg, Martin-Luther-King-Platz 6, D-20146 Hamburg (Germany)], E-mail: jose.broekaert@chemie.uni-hamburg.de

    2007-02-15

    The use of a so-called trihedral and a T-shaped cross-flow pneumatic nebulizer with dual solution loading for inductively coupled plasma optical emission spectrometry has been studied. By these devices analyte clouds from two solutions can be mixed during the aerosol generation step. For both nebulizers the correction of matrix effects using internal standardization and standard addition calibration in an on-line way was investigated and compared to elemental determinations using a conventional cross-flow nebulizer and calibration with synthetic standard solutions without matrix matching. A significant improvement of accuracy, both for calibration with internal standardization and standard addition, was obtained in the case of four synthetic solutions containing each 40 mmol L{sup -1} Na, K, Rb and Ba as matrix elements and 300 {mu}g L{sup -1} Cd, Co, Cr, Cu, Fe, Mn, Ni and Pb as analytes. Calibration by standard addition in the case of dual solution loading has been shown to be very useful in the determination of elements at minor and trace levels in steel and alumina reference materials. The results of analysis for minor concentrations of Cr, Cu and Ni in steel as well as for Ca, Fe, Ga, Li, Mg, Mn, Na, Si and Zn in alumina powder certified reference materials subsequent to sample dissolution were found to be in good agreement with the certificates. Limits of detection were found to be only slightly above those for a conventional cross-flow nebulizer and a precision better than 3% was realized with both novel nebulizers.

  19. Development of a Floating Element Wall Shear Transducer

    Science.gov (United States)

    1984-06-01

    Proceedings, vol. 2, Stanford Univ., pp. 1-45. Cook, N.H., 1963 Physical Measurement and Analysis, & Rabinowicz , E. Addison-Wesley, Reading, MA...Cook and Rabinowicz (1963) that if q = F(a i ) (C.2) where F is a function of n independent variables ai , then the most probable mean square error

  20. Finite Element Analysis of a Broadband Flextensional Transducer

    Science.gov (United States)

    1999-01-01

    frequence de resonance fondamentale, qui est de 10 % inferieure a la frequence mesuree. La gaine en caoutchouc , dont il n’etait pas tenu compte dans le...douves declasse Ill. On prevoit obtenir une plus grande precision en tenant compte de la gaine de caoutchouc dans le modele. CONTRACTOR REPORT

  1. Optimal design of a piezoelectric transducer for exciting guided wave ultrasound in rails

    Science.gov (United States)

    Ramatlo, Dineo A.; Wilke, Daniel N.; Loveday, Philip W.

    2017-02-01

    An existing Ultrasonic Broken Rail Detection System installed in South Africa on a heavy duty railway line is currently being upgraded to include defect detection and location. To accomplish this, an ultrasonic piezoelectric transducer to strongly excite a guided wave mode with energy concentrated in the web (web mode) of a rail is required. A previous study demonstrated that the recently developed SAFE-3D (Semi-Analytical Finite Element - 3 Dimensional) method can effectively predict the guided waves excited by a resonant piezoelectric transducer. In this study, the SAFE-3D model is used in the design optimization of a rail web transducer. A bound-constrained optimization problem was formulated to maximize the energy transmitted by the transducer in the web mode when driven by a pre-defined excitation signal. Dimensions of the transducer components were selected as the three design variables. A Latin hypercube sampled design of experiments that required a total of 500 SAFE-3D analyses in the design space was employed in a response surface-based optimization approach. The Nelder-Mead optimization algorithm was then used to find an optimal transducer design on the constructed response surface. The radial basis function response surface was first verified by comparing a number of predicted responses against the computed SAFE-3D responses. The performance of the optimal transducer predicted by the optimization algorithm on the response surface was also verified to be sufficiently accurate using SAFE-3D. The computational advantages of SAFE-3D in optimal transducer design are noteworthy as more than 500 analyses were performed. The optimal design was then manufactured and experimental measurements were used to validate the predicted performance. The adopted design method has demonstrated the capability to automate the design of transducers for a particular rail cross-section and frequency range.

  2. Micromachined ultrasound transducers with improved coupling factors from a CMOS compatible process

    Science.gov (United States)

    Eccardt; Niederer

    2000-03-01

    For medical high frequency acoustic imaging purposes the reduction in size of a single transducer element for one-dimensional and even more for two-dimensional arrays is more and more limited by fabrication and cabling technology. In the fields of industrial distance measurement and simple object recognition low cost phased arrays are lacking. Both problems can be solved with micromachined ultrasound transducers (MUTs). A single transducer is made of a large number of microscopic elements. Because of the array structure of these transducers, groups of elements can be built up and used as a phased array. By integrating parts of the sensor electronics on chip, the cabling effort for arrays can be reduced markedly. In contrast to standard ultrasonic technology, which is based on massive thickness resonators, vibrating membranes are the radiating elements of the MUTs. New micromachining technologies have emerged, allowing a highly reproducible fabrication of electrostatically driven membranes with gap heights below 500 nm. A microelectronic BiCMOS process was extended for surface micromechanics (T. Scheiter et al., Proceedings 11th European Conference on Solid-State Transducers, Warsaw, Vol. 3, 1997, pp. 1595-1598). Additional process steps were included for the realization of the membranes which form sealed cavities with the underlying substrate. Membrane and substrate are the opposite electrodes of a capacitive transducer. The transducers can be integrated monolithically on one chip together with the driving, preamplifying and multiplexing circuitry, thus reducing parasitic capacities and noise level significantly. Owing to their low mass the transducers are very well matched to fluid loads, resulting in a very high bandwidth of 50-100% (C. Eccardt et al., Proceedings Ultrasonics Symposium, San Antonio, Vol. 2, 1996, pp. 959-962; P.C. Eccardt et al., Proceedings of the 1997 Ultrasonics Symposium, Toronto, Vol. 2, 1997, pp. 1609-1618). In the following it is shown how

  3. 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.

  4. 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.

  5. Analyzing a Vibrating Wire Transducer using Coupled Resonator Circuits

    Directory of Open Access Journals (Sweden)

    POP, S.

    2015-08-01

    Full Text Available This paper intends to be an approach on the vibrating wire transducer from the perspective of the necessary rules used for a correct measurement procedure. There are several studies which analyze the vibrating wire transducer as a mechanical system. However, a comparative time-domain analysis between the mechanical and the electrical model is lacking. The transducer analysis is based on a theoretical analysis of the equivalent circuit, on both excitation and response time intervals. The electrical model consists of two magnetic coupled resonating circuits. When connected to an excitation source, there will be an energy transfer from the coil to the wire. The maximum energy transfer will occur at the vibrating wire's frequency of resonance. Using the transient regime analysis, it has been proven that, in the response time interval - when the wire vibrates freely, the current through the circuit that models the wire describes the oscillating movement of the wire. A complex signal is obtained, that contains both coil's and wire's frequencies of resonance, strongly dependent with theirs parasitic elements. The mathematical analysis highlights the similarity between mechanical and electrical model and the procedures in order to determine the wire frequency of resonance from the output signal.

  6. Piezoelectric pressure transducer technique for oxidizing atmospheres

    Science.gov (United States)

    Roberts, Ted A.; Burton, Rodney L.

    1992-07-01

    The diaphragm sensing tip of a high-speed piezoelectric pressure transducer can be destroyed when measuring transient impulse pressures in hot oxidizing atmospheres, e.g., oxygen at 3000 K and 34 atm for times of tens of milliseconds. A technique is presented to preserve the transducer under these conditions, which uses a protective layer of 0.025-0.050-mm-thick brass foil, held in place with double-sided tape. The integrity of the transducer is preserved, and the response time to a shock wave is increased from 1 to 2-6/microsec using the technique.

  7. 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.

  8. 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...

  9. 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...

  10. Molecular Electric Transducers as Motion Sensors: A Review

    Directory of Open Access Journals (Sweden)

    Hongyu Yu

    2013-04-01

    Full Text Available This article reviews the development of a new category of motion sensors including linear and angular accelerometers and seismometers based on molecular electronic transducer (MET technology. This technology utilizes a liquid not only as an inertial mass, but also as one of the main elements in the conversion of mechanical motion into electric current. The amplification process is similar to that in a vacuum triode. Therefore, it is possible to achieve signal amplification close to 108. Motion sensors demonstrating wide frequency and dynamic range and sensitivity that are one to two orders of magnitude better than MEMS devices of the same size have been developed.

  11. Thermal-independent properties of PIN-PMN-PT single-crystal linear-array ultrasonic transducers.

    Science.gov (United States)

    Chen, Ruimin; Wu, Jinchuan; Ho Lam, Kwok; Yao, Liheng; Zhou, Qifa; Tian, Jian; Han, Pengdi; Shung, K Kirk

    2012-12-01

    In this paper, low-frequency 32-element linear-array ultrasonic transducers were designed and fabricated using both ternary Pb(In(1/2)Nb(1/2))-Pb(Mg(1/3)Nb(2/3))-PbTiO(3) (PIN-PMN-PT) and binary Pb(Mg(1/3)Nb(2/3))-PbTiO(3) (PMNPT) single crystals. Performance of the array transducers was characterized as a function of temperature ranging from room temperature to 160°C. It was found that the array transducers fabricated using the PIN-PMN-PT single crystal were capable of satisfactory performance at 160°C, having a -6-dB bandwidth of 66% and an insertion loss of 37 dB. The results suggest that the potential of PIN-PMN-PT linear-array ultrasonic transducers for high-temperature ultrasonic transducer applications is promising.

  12. 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.

  13. Linear array transducer for high-power airborne ultrasound using flextensional structure

    Science.gov (United States)

    Yamamoto, Jun; Mizuno, Yosuke; Tabaru, Marie; Nakamura, Kentaro

    2015-07-01

    To change the direction of ultrasonic irradiation without moving a transducer, a high-power airborne ultrasonic transducer for a one-dimensional phased array system was designed and tested. A flextensional element transducer with higher-mode bending vibration was fabricated to obtain a high vibration amplitude over a wide aperture, where a phase-compensating stepped structure was employed. The width of the main lobe at half maximum and the sidelobe level were measured to be 14.3 deg and 0.78, respectively. The maximal sound pressure of 132 dB (0 dB re. 0.02 mPa) was obtained under the applied voltage of 4.0 V. The beam steering characteristics of a phased array using eight elements were compared with the simple theory.

  14. A Novel Traveling Wave Ultrasonic Motor Using a Bar Shaped Transducer

    Institute of Scientific and Technical Information of China (English)

    JIN Jiamei; ZHAO Chunsheng

    2008-01-01

    A novel traveling wave ultrasonic motor was proposed.The structure of the motor is rather simple and different from the conventional traveling wave ultra.sonic motors.Its production processes are very convenient.It is composed of a stator constituted with a ring and a bar shaped transducer and two cone shaped rotors.The rotors were pressed on inner surface of the ring by means of a pre-pressure system.The bar shaped transducer has a sandwich-like configuration,where two sets of piezoelectric element are bolted.One set excites a longitudinal vibration of the bar,and the other set excites a flexural vibration of the bar.The ring's traveling wave excited with the longitudinal vibration and the bending vibration of the bar transducer was simulated with FEM (finite element method).The prototype of the motor was made and investigated experimentally for its performance.Its maximum torque and ro

  15. D33 mode piezoelectric diaphragm based acoustic transducer with high sensitivity

    KAUST Repository

    Shen, Zhiyuan

    2013-01-01

    This paper presents the design, fabrication, and characterization of an acoustic transducer using a piezoelectric freestanding bulk diaphragm as the sensing element. The diaphragm bearing the spiral electrode operates in d 33 mode, which allows the in-plane deformation of the diaphragm to be converted to the out-of-plane deformation and generates an acoustic wave in the same direction. A finite element code is developed to reorient the material polarization distribution according to the poling field calculated. The first four resonance modes have been simulated and verified by impedance and velocity spectra. The sensitivity and the sound pressure level of the transducer were characterized. The realized sensitivity of 126.21 μV/Pa at 1 kHz is nearly twenty times of the sensitivity of a sandwich d31 mode transducer. © 2012 Elsevier B.V.

  16. 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.

  17. 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.

    strain gauge, semiconductor strain gauge, and quartz crystal beam. In this paper we examine the laboratory performance of a few temperature-compensated Honeywell silicon strain gauge pressure transducers based on their static calibration. 2. Silicon... Thin-Diaphragm Strain Gauge Pressure Transducer Although semiconductor materials such as germanium and silicon exhibit substantial temperature-dependence, they possess pressure-sensitivities several times that of metallic strain gauges. Silicon...

  18. Piezoelectric and Electrostrictive Materials for Transducer Applications.

    Science.gov (United States)

    1985-05-01

    Structure Ferroelastic Silicates" Alan Hain, Jr. B.S. Engineering Science, May 1984. "New Bimorph Structures with High Flexural Resonance Frequency" Eric ...Applications of PZT/Polymer Composite Materials,’ Ferroelectrics 39, 1245-1248 (1981). 22. Erikson , K.R. ’Tone-Burst Testing of Pulse-Echo Transducer...burst pulse-echo method described by Erikson [2]. A schematic diagram of the experimental set up is shown in Figure 1. The composite transducer was

  19. 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.

  20. DUAL MIXED FINITE ELEMENT METHOD FOR CONTACT PROBLEM IN ELASTICITY%弹性接触问题的对偶混合有限元分析

    Institute of Scientific and Technical Information of China (English)

    王烈衡; 王光辉

    1999-01-01

    In this paper, based on the mixed variational formulation in [9], a dualmixed variational formulation for contact problem in elasticity ispresented. The existence and uniqueness of the solution of the dualvariational problem are discussed, and the error bound O(h3/4) is obtained for Raviart-Thomas (k=1) element approximation.

  1. PRELIMINARY PROGRESS IN THE DEVELOPMENT OF DUCTILE-PHASE TOUGHENED TUNGSTEN FOR PLASMA-FACING MATERIALS: DUAL-PHASE FINITE ELEMENT DAMAGE MODELS

    Energy Technology Data Exchange (ETDEWEB)

    Henager, Charles H.; Nguyen, Ba Nghiep; Kurtz, Richard J.

    2016-09-30

    The objective of this study is to develop a finite element continuum damage model suitable for modeling deformation, cracking, and crack bridging for W-Cu, W-Ni-Fe, and other ductile phase toughened W-composites, or more generally, any multi-phase composite structure where two or more phases undergo cooperative deformation in a composite system.

  2. Two-dimensional refractive index modulation by phased array transducers in acousto-optic deflectors.

    Science.gov (United States)

    Wang, Tiansi; Zhang, Chong; Aleksov, Aleksandar; Salama, Islam; Kar, Aravinda

    2017-01-20

    Acousto-optic deflectors are photonic devices that are used for scanning high-power laser beams in advanced microprocessing applications such as marking and direct writing. The operation of conventional deflectors mostly relies on one-dimensional sinusoidal variation of the refractive index in an acousto-optic medium. Sometimes static phased array transducers, such as step configuration or planar configuration transducer architecture, are used to tilt the index modulation planes for achieving higher performance and higher resolution than a single transducer AO device. However, the index can be modulated in two dimensions, and the modulation plane can be tilted arbitrarily by creating dynamic phase gratings in the medium using phased array transducers. This type of dynamic two-dimensional acousto-optic deflector can provide better performance using, for example, a large deflection angle and high diffraction efficiency. This paper utilizes an ultrasonic beam steering approach to study the two-dimensional strain-induced index modulation due to the photoelastic effect. The modulation is numerically simulated, and the effects of various parameters, such as the operating radiofrequency of the transducers, the ultrasonic beam steering angle, and different combinations of pressure on each element of the transducer array, are demonstrated.

  3. A spiral wave front beacon for underwater navigation: transducer prototypes and testing.

    Science.gov (United States)

    Dzikowicz, Benjamin R; Hefner, Brian T

    2012-05-01

    Transducers for acoustic beacons which can produce outgoing signals with wave fronts whose horizontal cross sections are circular or spiral are studied experimentally. A remote hydrophone is used to determine its aspect relative to the transducers by comparing the phase of the circular signal to the phase of the spiral signal. The transducers for a "physical-spiral" beacon are made by forming a strip of 1-3 piezocomposite transducer material around either a circular or spiral backing. A "phased-spiral" beacon is made from an array of transducer elements which can be driven either in phase or staggered out of phase so as to produce signals with either a circular or spiral wave front. Measurements are made to study outgoing signals and their usefulness in determining aspect angle. Vertical beam width is also examined and phase corrections applied when the hydrophone is out of the horizontal plane of the beacon. While numerical simulations indicate that the discontinuity in the physical-spiral beacon introduces errors into the measured phase, damping observed at the ends of the piezocomposite material is a more significant source of error. This damping is also reflected in laser Doppler vibrometer measurements of the transducer's surface velocity.

  4. Double frequency piezoelectric transducer design for harmonic imaging purposes in NDT.

    Science.gov (United States)

    Montero de Espinosa, Francisco; Martínez, Oscar; Elvira Segura, Luis; Gómez-Ullate, Luis

    2005-06-01

    Harmonic imaging (HI) has emerged as a very promising tool for medical imaging, although there has been little published work using this technique in ultrasonic nondestructive testing (NDT). The core of the technique, which uses nonlinear propagation effects arising in the medium due to the microstructure or the existence of defects, is the ability to design transducers capable of emitting at one frequency and receiving at twice this frequency. The transducers that have been used so far are usually double crystal configurations with coaxial geometry, and commonly using a disc surrounded by a ring. Such a geometry permits the design of broadband transducers if each transducer element is adapted to the medium with its corresponding matching layers. Nevertheless, the different geometry of the emission and reception apertures creates difficulties when resolving the images. In this work, a new transducer design with different emission and reception apertures is resented. It makes use of the traditional construction procedures used to make piezocomposite transducers and the well-known theory of the mode coupling in piezoelectric resonators when the lateral dimensions are comparable with the thickness of the piezoceramic. In this work the design, construction, and characterization of a prototype to be used in NDT of metallic materials is presented. The acoustic field is calculated using water as a propagation medium, and these theoretical predictions then are compared with the experimental measurements. The predicted acoustic performances for the case of propagation in stainless steel are shown.

  5. Tonpilz Piezoelectric Transducer with a Bending Piezoelectric Disk on The Radiation Surface

    Science.gov (United States)

    Yamamoto, Mitsuru; Shiba, Hiroshi; Fujii, Taro; Hama, Yoshinori; Hoshino, Takamichi; Inoue, Takeshi

    2003-05-01

    In recent years, it has become necessary to use wide-band signals in various kinds of signal processing and communication technology fields. One of these is the field of underwater acoustic technology, and therefore wide-band transducers are needed in this field. To address this need, we developed a Tonpilz piezoelectric transducer with a bending piezoelectric disk on the radiation surface of the front mass. This transducer was designed by providing a bending piezoelectric disk on the radiation surface of the front mass of a conventional Tonpilz piezoelectric transducer to enable it to generate in two resonance modes: the longitudinal vibration resonance mode and the bending vibration resonance mode of the bending disk. Coupling these two resonance modes makes it possible to achieve low-frequency transmission, and wide-band signals can be attained by adjusting the phase in the two modes. We obtained the optimum design dimensions of the transducer through analysis using the finite element method (FEM), and constructed a prototype based on the analysis. Experiments verified that the measured results for the prototype correspond well to the simulation results and that the bandwidth can be widened without changing the external size of the conventional transducer.

  6. New technology for the design of advanced ultrasonic transducers for high-power applications.

    Science.gov (United States)

    Parrini, Lorenzo

    2003-06-01

    A new high-frequency ultrasonic transducer for wire bonding has been conceived, designed, prototyped and tested. In the design phase an advanced approach was used and established. The method is based on the two basic principles of modularity and iteration. The transducer is decomposed to its elementary components. For each component an initial design is obtained with finite elements method (FEM) simulations. The simulated ultrasonic modules are then built and characterized experimentally through laser-interferometry measurements and electrical resonance spectra. The comparison of simulation results with experimental data allows the parameters of FEM models to be iteratively adjusted and optimized. The achieved FEM simulations exhibit a remarkably high-predictive potential and allow full control on the vibration behavior of the ultrasonic modules and of the whole transducer. The new transducer is fixed on the wire bonder with a flange whose special geometry was calculated by means of FEM simulations. This flange allows the converter 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 nearly complete decoupling of the transducer to the wire bonder, which has not been previously obtained. 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.

  7. A New Fenchel Dual Problem in Vector Optimization

    Indian Academy of Sciences (India)

    Radu Ioan Boţ; Anca Dumitru; Gert Wanka

    2009-04-01

    We introduce a new Fenchel dual for vector optimization problems inspired by the form of the Fenchel dual attached to the scalarized primal multiobjective problem. For the vector primal-dual pair we prove weak and strong duality. Furthermore, we recall two other Fenchel-type dual problems introduced in the past in the literature, in the vector case, and make a comparison among all three duals. Moreover, we show that their sets of maximal elements are equal.

  8. Multivariate optimization and simultaneous determination of hydride and non-hydride-forming elements in samples of a wide pH range using dual-mode sample introduction with plasma techniques: application on leachates from cement mortar material.

    Science.gov (United States)

    Mulugeta, Mesay; Wibetoe, Grethe; Engelsen, Christian J; Asfaw, Alemayehu

    2009-02-01

    Analytical methods have been developed for the simultaneous determination of hydride-forming (As, Sb) and non-hydride-forming (Cr, Mo, V) elements in aqueous samples of a wide pH range (pH 3-13). The methods used dual-mode (DM) sample introduction with ICP-AES and ICP-MS instruments. The effect of selected experimental variables, i.e., sample pH and concentrations of HNO(3), thiourea, and NaBH(4), were studied in a multivariate way using face-centered central composite design (FC-CCD). Compromised optimum values of the experimental parameters were identified using a response optimizer. The statistically found optimum values were verified experimentally. The methods provided improved sensitivities for the hydride-forming elements compared with the respective conventional nebulization (Neb) systems by factors of 67 (As) and 64 (Sb) for ICP-AES and 36 (As) and 54 (Sb) for ICP-MS. Slight sensitivity improvements were also observed for the non-hydride-forming elements. The limits of detection (LOD) of As and Sb were lowered, respectively, to 0.8 and 0.9 microg L(-1) with the DM-ICP-AES system and to 0.01 and 0.02 microg L(-1) with the DM-ICP-MS system. The short-term stabilities of both methods were between 2.1 and 5.4%. The methods were applied for the analysis of leachates of a cement mortar material prepared in the pH range 3-13. The elemental concentration of the leachates determined by the two DM methods were statistically compared with the values obtained from Neb-ICP-MS analysis; the values showed good agreement at the 95% confidence level. Quantitative spike recoveries were obtained for the analytes from most of the leachates using both DM methods.

  9. [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.

  10. 21 CFR 870.2890 - Vessel occlusion transducer.

    Science.gov (United States)

    2010-04-01

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

  11. 21 CFR 870.2850 - Extravascular blood pressure transducer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Extravascular blood pressure transducer. 870.2850... blood pressure transducer. (a) Identification. An extravascular blood pressure transducer is a device... proximal end of the transducer is connected to a pressure monitor that produces an analog or digital...

  12. 21 CFR 870.2060 - Transducer signal amplifier and conditioner.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Transducer signal amplifier and conditioner. 870... Transducer signal amplifier and conditioner. (a) Identification. A transducer signal amplifier and conditioner is a device used to provide the excitation energy for the transducer and to amplify or condition...

  13. 21 CFR 870.2860 - Heart sound transducer.

    Science.gov (United States)

    2010-04-01

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

  14. The effect of electronically steering a phased array ultrasound transducer on near-field tissue heating

    Science.gov (United States)

    Payne, Allison; Vyas, Urvi; Todd, Nick; Bever, Joshua de; Christensen, Douglas A.; Parker, Dennis L.

    2011-01-01

    Purpose: This study presents the results obtained from both simulation and experimental techniques that show the effect of mechanically or electronically steering a phased array transducer on proximal tissue heating. Methods: The thermal response of a nine-position raster and a 16-mm diameter circle scanning trajectory executed through both electronic and mechanical scanning was evaluated in computer simulations and experimentally in a homogeneous tissue-mimicking phantom. Simulations were performed using power deposition maps obtained from the hybrid angular spectrum (HAS) method and applying a finite-difference approximation of the Pennes’ bioheat transfer equation for the experimentally used transducer and also for a fully sampled transducer to demonstrate the effect of acoustic window, ultrasound beam overlap and grating lobe clutter on near-field heating. Results: Both simulation and experimental results show that electronically steering the ultrasound beam for the two trajectories using the 256-element phased array significantly increases the thermal dose deposited in the near-field tissues when compared with the same treatment executed through mechanical steering only. In addition, the individual contributions of both beam overlap and grating lobe clutter to the near-field thermal effects were determined through comparing the simulated ultrasound beam patterns and resulting temperature fields from mechanically and electronically steered trajectories using the 256-randomized element phased array transducer to an electronically steered trajectory using a fully sampled transducer with 40 401 phase-adjusted sample points. Conclusions: Three distinctly different three distinctly different transducers were simulated to analyze the tradeoffs of selected transducer design parameters on near-field heating. Careful consideration of design tradeoffs and accurate patient treatment planning combined with thorough monitoring of the near-field tissue temperature will

  15. The effect of electronically steering a phased array ultrasound transducer on near-field tissue heating.

    Science.gov (United States)

    Payne, Allison; Vyas, Urvi; Todd, Nick; de Bever, Joshua; Christensen, Douglas A; Parker, Dennis L

    2011-09-01

    This study presents the results obtained from both simulation and experimental techniques that show the effect of mechanically or electronically steering a phased array transducer on proximal tissue heating. The thermal response of a nine-position raster and a 16-mm diameter circle scanning trajectory executed through both electronic and mechanical scanning was evaluated in computer simulations and experimentally in a homogeneous tissue-mimicking phantom. Simulations were performed using power deposition maps obtained from the hybrid angular spectrum (HAS) method and applying a finite-difference approximation of the Pennes' bioheat transfer equation for the experimentally used transducer and also for a fully sampled transducer to demonstrate the effect of acoustic window, ultrasound beam overlap and grating lobe clutter on near-field heating. Both simulation and experimental results show that electronically steering the ultrasound beam for the two trajectories using the 256-element phased array significantly increases the thermal dose deposited in the near-field tissues when compared with the same treatment executed through mechanical steering only. In addition, the individual contributions of both beam overlap and grating lobe clutter to the near-field thermal effects were determined through comparing the simulated ultrasound beam patterns and resulting temperature fields from mechanically and electronically steered trajectories using the 256-randomized element phased array transducer to an electronically steered trajectory using a fully sampled transducer with 40 401 phase-adjusted sample points. Three distinctly different three distinctly different transducers were simulated to analyze the tradeoffs of selected transducer design parameters on near-field heating. Careful consideration of design tradeoffs and accurate patient treatment planning combined with thorough monitoring of the near-field tissue temperature will help to ensure patient safety during an MRg

  16. Research on Effective Electric-Mechanical Coupling Coefficient of Sandwich Type Piezoelectric Ultrasonic Transducer Using Bending Vibration Mode

    Directory of Open Access Journals (Sweden)

    Qiang Zhang

    2015-01-01

    Full Text Available An analytical model on electromechanical coupling coefficient and the length optimization of a bending piezoelectric ultrasonic transducer are proposed. The piezoelectric transducer consists of 8 PZT elements sandwiched between four thin electrodes, and the PZT elements are clamped by a screwed connection between fore beam and back beam. Firstly, bending vibration model of the piezoelectric transducer is built based on the Timoshenko beam theory. Secondly, the analytical model of effective electromechanical coupling coefficient is built based on the bending vibration model. Energy method and electromechanical equivalent circuit method are involved in the modelling process. To validate the analytical model, sandwich type piezoelectric transducer example in second order bending vibration mode is analysed. Effective electromechanical coupling coefficient of the transducer is optimized with simplex reflection technique, and the optimized ratio of length of the transducers is obtained. Finally, experimental prototypes of the sandwich type piezoelectric transducers are fabricated. Bending vibration mode and impedance of the experimental prototypes are tested, and electromechanical coupling coefficient is obtained according to the testing results. Results show that the analytical model is in good agreement with the experimental model.

  17. Piezoelectric Micromachined Ultrasound Transducer (PMUT Arrays for Integrated Sensing, Actuation and Imaging

    Directory of Open Access Journals (Sweden)

    Yongqiang Qiu

    2015-04-01

    Full Text Available Many applications of ultrasound for sensing, actuation and imaging require miniaturized and low power transducers and transducer arrays integrated with electronic systems. Piezoelectric micromachined ultrasound transducers (PMUTs, diaphragm-like thin film flexural transducers typically formed on silicon substrates, are a potential solution for integrated transducer arrays. This paper presents an overview of the current development status of PMUTs and a discussion of their suitability for miniaturized and integrated devices. The thin film piezoelectric materials required to functionalize these devices are discussed, followed by the microfabrication techniques used to create PMUT elements and the constraints the fabrication imposes on device design. Approaches for electrical interconnection and integration with on-chip electronics are discussed. Electrical and acoustic measurements from fabricated PMUT arrays with up to 320 diaphragm elements are presented. The PMUTs are shown to be broadband devices with an operating frequency which is tunable by tailoring the lateral dimensions of the flexural membrane or the thicknesses of the constituent layers. Finally, the outlook for future development of PMUT technology and the potential applications made feasible by integrated PMUT devices are discussed.

  18. Piezoelectric micromachined ultrasound transducer (PMUT) arrays for integrated sensing, actuation and imaging.

    Science.gov (United States)

    Qiu, Yongqiang; Gigliotti, James V; Wallace, Margeaux; Griggio, Flavio; Demore, Christine E M; Cochran, Sandy; Trolier-McKinstry, Susan

    2015-04-03

    Many applications of ultrasound for sensing, actuation and imaging require miniaturized and low power transducers and transducer arrays integrated with electronic systems. Piezoelectric micromachined ultrasound transducers (PMUTs), diaphragm-like thin film flexural transducers typically formed on silicon substrates, are a potential solution for integrated transducer arrays. This paper presents an overview of the current development status of PMUTs and a discussion of their suitability for miniaturized and integrated devices. The thin film piezoelectric materials required to functionalize these devices are discussed, followed by the microfabrication techniques used to create PMUT elements and the constraints the fabrication imposes on device design. Approaches for electrical interconnection and integration with on-chip electronics are discussed. Electrical and acoustic measurements from fabricated PMUT arrays with up to 320 diaphragm elements are presented. The PMUTs are shown to be broadband devices with an operating frequency which is tunable by tailoring the lateral dimensions of the flexural membrane or the thicknesses of the constituent layers. Finally, the outlook for future development of PMUT technology and the potential applications made feasible by integrated PMUT devices are discussed.

  19. The design of a vibration transducer to monitor the integrity of dental implants.

    Science.gov (United States)

    Cawley, P; Pavlakovic, B; Alleyne, D N; George, R; Back, T; Meredith, N

    1998-01-01

    Bone-anchored titanium implants are being used increasingly to provide support for prostheses replacing missing teeth in edentulous and partially dentate patients. A technique is required to monitor bone formation at the implant-tissue interface during healing, and also to check whether there has been bone loss from around the top of the implant. One possible method is to screw a beam into the implanted fixture and to measure the first flexural resonance frequency of the resulting system. This resonance frequency is affected by both the exposed length of fixture and the stiffness of the interface between the implant and the bone. This paper describes the design of a beam-like transducer for clinical trials of the technique. The sensitivity of the transducer resonance frequency to the changes of interest is dependent on the thickness and length of the beam element. However, the choice of these dimensions is constrained by the need to avoid closely spaced resonances. The performance of different transducer shapes and the influence of the thickness and length of the beam element in the transducer has been studied. The results have been used to finalize a transducer design for the clinical trials.

  20. Guided wave structural health monitoring with an array of novel piezoelectric transducers

    Science.gov (United States)

    Lesky, A.; Lissenden, C. J.

    2014-02-01

    Multi-element, conformable piezoelectric strip transducers have been designed and fabricated for structural health monitoring using ultrasonic guided waves. The piezoelectric fiber composite elements function as a strip transducer to activate a planar wave. A mockup of a storage tank or pressure vessel has been constructed from a steel shell and a hexagonal array of strip transducers. A hot spot to which artificial damage has been induced is monitored with the strip transducers. In addition, conventional piezoelectric disks have also been affixed to the shell in a circular pattern for the purpose of comparison. Different operating conditions are represented by the presence of water inside the shell and temperature variations between 20 and 35°C. The strip transducers have been designed to excite the S1 Lamb wave mode at the dilatational wave speed, which is oblivious to the presence of liquid loaded boundary conditions. An artificial defect simulated a surface breaking fatigue crack. Preliminary results are presented for baseline and damaged conditions using transmission and reflection coefficients as a damage-sensitive feature. At the request of the Proceedings Editor, and all authors of the paper, an updated version of this article was published on 8 April 2014. The Corrigendum attached to the corrected article PDF file explains the changes made to the original paper.

  1. Three-dimensional real-time synthetic aperture imaging using a rotating phased array transducer

    DEFF Research Database (Denmark)

    Nikolov, Svetoslav; Dufait, Remi; Schoisswohl, Armin

    2002-01-01

    the plane located directly below the transducer, but also from neighboring planes. A complete dataset for all elements for the whole rotation is acquired and stored. The volume is then focused from this complete data set in order to obtain dynamic transmit and receive focusing in all directions....

  2. On-chip RF-to-optical transducer (Conference Presentation)

    Science.gov (United States)

    Simonsen, Anders; Tsaturyan, Yeghishe; Seis, Yannick; Schmid, Silvan; Schliesser, Albert; Polzik, Eugene S.

    2016-04-01

    Recent advances in the fabrication of nano- and micromechanical elements enable the realization of high-quality mechanical resonators with masses so small that the forces from optical photons can have a significant impact on their motion. This facilitates a strong interaction between mechanical motion and light, or phonons and photons. This interaction is the corner stone of the field of optomechanics and allows, for example, for ultrasensitive detection and manipulation of mechanical motion using laser light. Remarkably, today these techniques can be extended into the quantum regime, in which fundamental fluctuations of light and mechanics govern the system's behavior. Micromechanical elements can also interact strongly with other physical systems, which is the central aspect of many micro-electro-mechanical based sensors. Micromechanical elements can therefore act as a bridge between these diverse systems, plus technologies that utilize them, and the mature toolbox of optical techniques that routinely operates at the quantum limit. In a previous work [1], we demonstrated such a bridge by realizing simultaneous coupling between an electronic LC circuit and a quantum-noise limited optical interferometer. The coupling was mediated by a mechanical oscillator forming a mechanically compliant capacitor biased with a DC voltage. The latter enhances the electromechanical interaction all the way to the strong coupling regime. That scheme allowed optical detection of electronic signals with effective noise temperatures far below the actual temperature of the mechanical element. On-chip integration of the electrical, mechanical and optical elements is necessary for an implementation of the transduction scheme that is viable for commercial applications. Reliable assembly of a strongly coupled electromechanical device, and inclusion of an optical cavity for enhanced optical readout, are key features of the new platform. Both can be achieved with standard cleanroom fabrication

  3. Neuron-restrictive silencer factor (NRSF) represses cocaine- and amphetamine-regulated transcript (CART) transcription and antagonizes cAMP-response element-binding protein signaling through a dual NRSE mechanism.

    Science.gov (United States)

    Zhang, Jing; Wang, Sihan; Yuan, Lin; Yang, Yinxiang; Zhang, Bowen; Liu, Qingbin; Chen, Lin; Yue, Wen; Li, Yanhua; Pei, Xuetao

    2012-12-14

    Cocaine- and amphetamine-regulated transcript (CART) peptide plays a pivotal role in neuroprotection against stroke-related brain injury. However, the regulatory mechanism on CART transcription, especially the repression mechanism, is not fully understood. Here, we show that the transcriptional repressor neuron-restrictive silencer elements (NRSF, also known as REST) represses CART expression through direct binding to two NRSF-binding elements (NRSEs) in the CART promoter and intron 1 (named pNRSE and iNRSE, respectively). EMSA show that NRSF binds to pNRSE and iNRSE directly in vitro. ChIP assays show that NRSF recruits differential co-repressor complexes including CoREST and HDAC1 to these NRSEs. The presence of both NRSEs is required for efficient repression of CART transcription as indicated by reporter gene assays. NRSF overexpression antagonizes forskolin-mediated up-regulation of CART mRNA and protein. Ischemia insult triggered by oxygen-glucose deprivation (OGD) enhances NRSF mRNA levels and then NRSF antagonizes the CREB signaling on CART activation, leading to augmented cell death. Depletion of NRSF in combination with forskolin treatment increases neuronal survival after ischemic insult. These findings reveal a novel dual NRSE mechanism by which NRSF represses CART expression and suggest that NRSF may serve as a therapeutic target for stroke treatment.

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

    Science.gov (United States)

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

    2012-11-01

    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. Experiments showed a 15 dB increase of the signal-to-noise ratio (SNR) when beamforming was employed compared to the images acquired with each single element. The experimental results demonstrated that ultrasonic phased array can be a better candidate for LS-PAM in high sensitivity applications like ophthalmic imaging.

  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. 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.

  7. High Temperature, High Power Piezoelectric Composite Transducers

    Directory of Open Access Journals (Sweden)

    Hyeong Jae Lee

    2014-08-01

    Full Text Available 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.

  8. Se-Hg Dual-element Labeling Strategy for Selectively Recognizing Selenoprotein and Selenopeptide%硒-汞双元素标记策略识别硒蛋白/多肽

    Institute of Scientific and Technical Information of China (English)

    徐明; 杨利民; 王秋泉

    2015-01-01

    提出并发展了一种基于电感耦合等离子体质谱( ICP-MS)的双元素标签标记策略来选择性识别和检测硒蛋白/多肽,其中内源元素硒( Se)作为硒蛋白/多肽分子的识别元素,外源元素汞( Hg)作为硒蛋白/多肽和含硒蛋白/多肽分子的区分元素。通过对硒代半胱氨酸(SeCys)和谷胱甘肽过氧化酶1(GPx1)两种模型分子的研究,外源邻羧基苯硫甲基汞( CH3 Hg-THI )动态解离的 CH3 Hg+能够选择性标记硒代半胱氨酸残基( SeCys)中硒醇基(-SeH),但不能标记含硒蛋白/多肽分子的硒代蛋氨酸残基( SeMet)中的—SeCH3,进而依据Se和Hg的ICP-MS信号识别和检测硒蛋白/多肽。本方法应用于富硒酵母水溶性提取液的分析,结果表明,提取液中的硒蛋白/多肽能够被有效识别和检测,验证了Se-Hg双元素标签标记策略的发展是ICP-MS识别和检测硒蛋白/多肽的一种可行且优越的途径。%An endogenous element-label plus exogenous element-tag strategy was proposed for inductively coupled plasma mass spectrometry ( ICP-MS) to screen and discriminate a family of ultratrace but biological important biomolecules. The feasibility of this novel idea has been demonstrated when setting seleno ( SeCys) and Se-containing ( SeMet) proteins ( peptides) as an example. Se-label naturally occurring in the biomole-cules acts an identifier for picking them up out of large amount of various coexisting proteins ( peptides) , and CH3 Hg-tag that can bind to SeCys but not SeMet fulfills the task of discriminating seleno and Se-containing ones based on the Se and Hg signals on ICP-MS. After confirmed using SeCys and GPx1, the Se-Hg dual-element labeling strategy together with ICP-MS was applied to screen and discriminate seleno and Se-contai-ning proteins ( peptides) in the water-soluble extracts of Se-enriched yeast, and seven selenoproteins ( pep-tides) were detected with both 202 Hg and 82 Se signals out of fifteen Se

  9. Advanced 3-D Ultrasound Imaging: 3-D Synthetic Aperture Imaging using Fully Addressed and Row-Column Addressed 2-D Transducer Arrays

    DEFF Research Database (Denmark)

    Bouzari, Hamed

    with transducer arrays using this addressing scheme, when integrated into probe handles. For that reason, two in-house prototyped 62+62 row-column addressed 2-D array transducer probes were manufactured using capacitive micromachined ultrasonic transducer (CMUT) and piezoelectric transducer (PZT) technology...... in many clinical applications. Real-time 3-D ultrasound imaging is still not as widespread in use in the clinics as 2-D ultrasound imaging. Two limiting factors have traditionally been the low image quality as well as low volume rate achievable with a 2-D transducer array using the conventional 3-D...... and measurements with the ultrasound research scanner SARUS and a 3.8 MHz 1024 element 2-D transducer array. In all investigations, 3-D synthetic aperture imaging achieved a better resolution, lower side-lobes, higher contrast, and better signal to noise ratio than parallel beamforming. This is achieved partly...

  10. Production of particulates from transducer erosion: implications on food safety.

    Science.gov (United States)

    Mawson, Raymond; Rout, Manoj; Ripoll, Gabriela; Swiergon, Piotr; Singh, Tanoj; Knoerzer, Kai; Juliano, Pablo

    2014-11-01

    The formation of metallic particulates from erosion was investigated by running a series of transducers at various frequencies in water. Two low frequency transducer sonotrodes were run for 7.5h at 18kHz and 20kHz. Three high frequency plates operating at megasonic frequencies of 0.4MHz, 1MHz, and 2MHz were run over a 7days period. Electrical conductivity and pH of the solution were measured before and after each run. A portion of the non-sonicated and treated water was partially evaporated to achieve an 80-fold concentration of particles and then sieved through nano-filters of 0.1μm, 0.05μm, and 0.01μm. An aliquot of the evaporated liquid was also completely dried on strips of carbon tape to determine the presence of finer particles post sieving. An aliquot was analyzed for detection of 11 trace elements by Inductively Coupled Plasma Mass Spectroscopy (ICPMS). The filters and carbon tapes were analyzed by FE-SEM imaging to track the presence of metals by EDS (Energy Dispersive Spectroscopy) and measure the particle size and approximate composition of individual particles detected. Light microscopy visualization was used to calculate the area occupied by the particles present in each filter and high resolution photography was used for visualization of sonotrode surfaces. The roughness of all transducers before and after sonication was tested through profilometry. No evidence of formation of nano-particles was found at any tested frequency. High amounts of metallic micron-sized particles at 18kHz and 20kHz formed within a day, while after 7day runs only a few metallic micro particles were detected above 0.4MHz. Erosion was corroborated by an increase in roughness in the 20kHz tip after ultrasound. The elemental analysis showed that metal leach occurred but values remained below accepted drinking water limits, even after excessively long exposure to ultrasound. With the proviso that the particles measured here were only characterized in two dimensions and could be

  11. Optically transduced MEMS gyro device

    Energy Technology Data Exchange (ETDEWEB)

    Nielson, Gregory N; Bogart, Gregory R; Langlois, Eric; Okandan, Murat

    2014-05-20

    A bulk micromachined vibratory gyro in which a proof mass has a bulk substrate thickness for a large mass and high inertial sensitivity. In embodiments, optical displacement transduction is with multi-layer sub-wavelength gratings for high sensitivity and low cross-talk with non-optical drive elements. In embodiments, the vibratory gyro includes a plurality of multi-layer sub-wavelength gratings and a plurality of drive electrodes to measure motion of the proof mass induced by drive forces and/or moments and induced by the Coriolis Effect when the gyro experiences a rotation. In embodiments, phase is varied across the plurality gratings and a multi-layer grating having the best performance is selected from the plurality.

  12. 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.

  13. Front-end receiver electronics for a matrix transducer for 3-D transesophageal echocardiography.

    Science.gov (United States)

    Yu, Zili; Blaak, Sandra; Chang, Zu-yao; Yao, Jiajian; Bosch, Johan G; Prins, Christian; Lancée, Charles T; de Jong, Nico; Pertijs, Michiel A P; Meijer, Gerard C M

    2012-07-01

    There is a clear clinical need for creating 3-D images of the heart. One promising technique is the use of transesophageal echocardiography (TEE). To enable 3-D TEE, we are developing a miniature ultrasound probe containing a matrix piezoelectric transducer with more than 2000 elements. Because a gastroscopic tube cannot accommodate the cables needed to connect all transducer elements directly to an imaging system, a major challenge is to locally reduce the number of channels, while maintaining a sufficient signal-to-noise ratio. This can be achieved by using front-end receiver electronics bonded to the transducers to provide appropriate signal conditioning in the tip of the probe. This paper presents the design of such electronics, realizing time-gain compensation (TGC) and micro-beamforming using simple, low-power circuits. Prototypes of TGC amplifiers and micro-beamforming cells have been fabricated in 0.35-μm CMOS technology. These prototype chips have been combined on a printed circuit board (PCB) to form an ultrasound-receiver system capable of reading and combining the signals of three transducer elements. Experimental results show that this design is a suitable candidate for 3-D TEE.

  14. A new omnidirectional shear horizontal wave transducer using face-shear (d24) piezoelectric ring array.

    Science.gov (United States)

    Miao, Hongchen; Huan, Qiang; Wang, Qiangzhong; Li, Faxin

    2017-02-01

    The non-dispersive fundamental shear horizontal (SH0) wave in plate-like structures is of practical importance in non-destructive testing (NDT) and structural health monitoring (SHM). Theoretically, an omnidirectional SH0 transducer phased array system can be used to inspect defects in a large plate in the similar manner to the phased array transducers used in medical B-scan ultrasonics. However, very few omnidirectional SH0 transducers have been proposed so far. In this work, an omnidirectional SH0 wave piezoelectric transducer (OSH-PT) was proposed, which consists of a ring array of twelve face-shear (d24) trapezoidal PZT elements. Each PZT element can produce face-shear deformation under applied voltage, resulting in circumferential shear deformation in the OSH-PT and omnidirectional SH0 waves in the hosting plate. Both finite element simulations and experiments were conducted to examine the performance of the proposed OSH-PT. Experimental testing shows that the OSH-PT exhibits good omnidirectional properties, no matter it is used as a SH0 wave transmitter or a SH0 wave receiver. This work may greatly promote the applications of SH0 waves in NDT and SHM.

  15. 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.

  16. Dual diagnosis

    OpenAIRE

    2013-01-01

    Dual diagnosis denotes intertwining of intellectual disabilities with mental disorders. With the help of systematic examination of literature, intellectual disabilities are determined (they are characterized by subaverage intellectual activity and difficulties in adaptive skills), along side mental disorders. Their influence is seen in changes of thinking, perception, emotionality, behaviour and cognition. Mental disorders often occur with people with intellectual disabilities (data differs f...

  17. Frequency dependence of the acoustic field generated from a spherical cavity transducer with open ends

    Energy Technology Data Exchange (ETDEWEB)

    Li, Faqi; Zeng, Deping; He, Min; Wang, Zhibiao, E-mail: dzhang@nju.edu.cn, E-mail: wangzhibiao@haifu.com.cn [State Key Laboratory of Ultrasound Engineering in Medicine Co-founded by Chongqing and the Ministry of Science and Technology, College of Biomedical Engineering, Chongqing Medical University, Chongqing 401121 (China); Song, Dan; Lei, Guangrong [National Engineering Research Center of Ultrasound Medicine, Chongqing 401121 (China); Lin, Zhou; Zhang, Dong, E-mail: dzhang@nju.edu.cn, E-mail: wangzhibiao@haifu.com.cn [Institute of Acoustics, Key Laboratory of Modern Acoustics, MOE, Nanjing University, Nanjing 210093 (China); Wu, Junru [Department of Physics, University of Vermont, Burlington, VT 05405 (United States)

    2015-12-15

    Resolution of high intensity focused ultrasound (HIFU) focusing is limited by the wave diffraction. We have developed a spherical cavity transducer with two open ends to improve the focusing precision without sacrificing the acoustic intensity (App Phys Lett 2013; 102: 204102). This work aims to theoretically and experimentally investigate the frequency dependence of the acoustic field generated from the spherical cavity transducer with two open ends. The device emits high intensity ultrasound at the frequency ranging from 420 to 470 kHz, and the acoustic field is measured by a fiber optic probe hydrophone. The measured results shows that the spherical cavity transducer provides high acoustic intensity for HIFU treatment only in its resonant modes, and a series of resonant frequencies can be choosen. Furthermore, a finite element model is developed to discuss the frequency dependence of the acoustic field. The numerical simulations coincide well with the measured results.

  18. Piezoelectric transducer parameter selection for exciting a single mode from multiple modes of Lamb waves

    Institute of Scientific and Technical Information of China (English)

    Rang Hai-Yan; Yu Jian-Bo

    2011-01-01

    Excitation and propagation of Lamb waves by using rectangular and circular piezoelectric transducers surfacebonded to an isotropic plate are investigated in this work. Analytical stain wave solutions are derived for the two transducer shapes,giving the responses of these transducers in Lamb wave fields. The analytical study is supported by a numerical simulation using the finite element method. Symmetric and antisymmetric components in the wave propagation responses are inspected in detail with respect to test parameters such as the transducer geometry,the length and the excitation frequency. By placing only one piezoelectric transducer on the top or the bottom surface of the plate and weakening the strength of one mode while enhancing the strength of the other modes to find the centre frequency,with which the peak wave amplitude ratio between the S0 and A0 modes is maximum,a single mode excitation from the multiple modes of the Lamb waves can be achieved approximately. Experimental data are presented to show the validity of the analyses. The results are used to optimize the Lamb wave detection system.

  19. Performance of PZT8 Versus PZT4 Piezoceramic Materials in Ultrasonic Transducers

    Science.gov (United States)

    DeAngelis, Dominick A.; Schulze, Gary W.

    PZT8 and PZT4 are the common "hard" piezoceramic materials used in power ultrasonic transducers (e.g., welding, cutting, sonar, etc.). PZT8 is perceived as the better choice for resonant devices, primarily due to its higher mechanical quality factor Qm. PZT8 is also considered a "harder" material compared to PZT4, since it has better stability at higher preloads and drive levels. Many transducer designers never consider PZT4 for their applications, even though it has clear advantages such as higher output (i.e., higher d33). Even the perceived advantage of PZT8 regarding Qm may not be significant for most Langevin, bolted stack type transducers if the mechanical joint losses dominate. This research is a case study on the performance of identical ultrasonic transducers used for semiconductor wire bonding, assembled with either PZT8 or PZT4 materials. The main purpose of the study is to establish rule-of-thumb transducer design guidelines for the selection of PZT8 versus PZT4 materials. Several metrics are investigated such as impedance, frequency, capacitance, dielectric loss, Qm, heating, displacement gain, and electro-mechanical coupling factor. The experimental and theoretical research methods include Bode plots, thermal IR camera imaging, scanning laser vibrometry and coupled-field finite element analysis.

  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. 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.

  2. 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.

  3. Eliminating transducer distortion in acoustic measurements

    DEFF Research Database (Denmark)

    Agerkvist, Finn T.; Torras Rosell, Antoni; McWalter, Richard Ian

    2014-01-01

    This paper investigates the in uence of nonlinear components that contaminate the linear response of acoustic transducer, and presents a method for eliminating the in uence of nonlinearities in acoustic measurements. The method is evaluated on simulated as well as experimental data, and is shown...

  4. 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

  5. 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.

  6. Numerical modeling of piezoelectric transducers using physical parameters.

    Science.gov (United States)

    Cappon, Hans; Keesman, Karel J

    2012-05-01

    Design of ultrasonic equipment is frequently facilitated with numerical models. These numerical models, however, need a calibration step, because usually not all characteristics of the materials used are known. Characterization of material properties combined with numerical simulations and experimental data can be used to acquire valid estimates of the material parameters. In our design application, a finite element (FE) model of an ultrasonic particle separator, driven by an ultrasonic transducer in thickness mode, is required. A limited set of material parameters for the piezoelectric transducer were obtained from the manufacturer, thus preserving prior physical knowledge to a large extent. The remaining unknown parameters were estimated from impedance analysis with a simple experimental setup combined with a numerical optimization routine using 2-D and 3-D FE models. Thus, a full set of physically interpretable material parameters was obtained for our specific purpose. The approach provides adequate accuracy of the estimates of the material parameters, near 1%. These parameter estimates will subsequently be applied in future design simulations, without the need to go through an entire series of characterization experiments. Finally, a sensitivity study showed that small variations of 1% in the main parameters caused changes near 1% in the eigenfrequency, but changes up to 7% in the admittance peak, thus influencing the efficiency of the system. Temperature will already cause these small variations in response; thus, a frequency control unit is required when actually manufacturing an efficient ultrasonic separation system.

  7. Evolvable Cryogenics (ECRYO) Pressure Transducer Calibration Test

    Science.gov (United States)

    Diaz, Carlos E., Jr.

    2015-01-01

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

  8. Development of a 20-MHz wide-bandwidth PMN-PT single crystal phased-array ultrasound transducer.

    Science.gov (United States)

    Wong, Chi-Man; Chen, Yan; Luo, Haosu; Dai, Jiyan; Lam, Kwok-Ho; Chan, Helen Lai-Wa

    2017-01-01

    In this study, a 20-MHz 64-element phased-array ultrasound transducer with a one-wavelength pitch is developed using a PMN-30%PT single crystal and double-matching layer scheme. High piezoelectric (d33>1000pC/N) and electromechanical coupling (k33>0.8) properties of the single crystal with an optimized fabrication process involving the photolithography technique have been demonstrated to be suitable for wide-bandwidth (⩾70%) and high-sensitivity (insertion loss ⩽30dB) phased-array transducer application. A -6dBbandwidth of 91% and an insertion loss of 29dBfor the 20-MHz 64-element phased-array transducer were achieved. This result shows that the bandwidth is improved comparing with the investigated high-frequency (⩾20MHz) ultrasound transducers using piezoelectric ceramic and single crystal materials. It shows that this phased-array transducer has potential to improve the resolution of biomedical imaging, theoretically. Based on the hypothesis of resolution improvement, this phased-array transducer is capable for small animal (i.e. mouse and zebrafish) studies.

  9. A beamforming study for implementation of vibro-acoustography with a 1.75-D array transducer.

    Science.gov (United States)

    Urban, Matthew W; Chalek, Carl; Haider, Bruno; Thomenius, Kai E; Fatemi, Mostafa; Alizad, Azra

    2013-03-01

    Vibro-acoustography (VA) is an ultrasound-based imaging modality that uses radiation force produced by two cofocused ultrasound beams separated by a small frequency difference, Δf, to vibrate tissue at Δf. An acoustic field is created by the object vibration and measured with a nearby hydrophone. This method has recently been implemented on a clinical ultrasound system using 1-D linear-array transducers. In this article, we discuss VA beamforming and image formation using a 1.75-D array transducer. A 1.75-D array transducer has several rows of elements in the elevation direction which can be controlled independently for focusing. The advantage of the 1.75-D array over a 1-D linear-array transducer is that multiple rows of elements can be used for improving elevation focus for imaging formation. Six configurations for subaperture design for the two ultrasound beams necessary for VA imaging were analyzed. The point-spread functions for these different configurations were evaluated using a numerical simulation model. Four of these configurations were then chosen for experimental evaluation with a needle hydrophone as well as for scanning two phantoms. Images were formed by scanning a urethane breast phantom and an ex vivo human prostate. VA imaging using a 1.75-D array transducer offers several advantages over scanning with a linear-array transducer, including improved image resolution and contrast resulting from better elevation focusing of the imaging point-spread function.

  10. A Beamforming Study for Implementation of Vibro-acoustography with a 1.75D Array Transducer

    Science.gov (United States)

    Urban, Matthew W.; Chalek, Carl; Haider, Bruno; Thomenius, Kai E.; Fatemi, Mostafa; Alizad, Azra

    2013-01-01

    Vibro-acoustography (VA) is an ultrasound-based imaging modality that uses radiation force produced by two cofocused ultrasound beams separated by a small frequency difference, Δf, to vibrate tissue at Δf. An acoustic field is created by the object vibration and measured with a nearby hydrophone. This method has recently been implemented on a clinical ultrasound system using one-dimensional (1D) linear array transducers. In this article, we discuss VA beamforming and image formation using a 1.75D array transducer. A 1.75D array transducer has several rows of elements in the elevation direction which can be controlled independently for focusing. The advantage of the 1.75D array over a 1D linear array transducer is that multiple rows of elements can be used for improving elevation focus for imaging formation. Six configurations for subaperture design for the two ultrasound beams necessary for VA imaging were analyzed. The point-spread functions for these different configurations were evaluated using a numerical simulation model. Four of these configurations were then chosen for experimental evaluation with a needle hydrophone as well as for scanning two phantoms. Images were formed by scanning a urethane breast phantom and an ex vivo human prostate. VA imaging using a 1.75D array transducer offers several advantages over scanning with a linear array transducer including improved image resolution and contrast due to better elevation focusing of the imaging point-spread function. PMID:23475919

  11. Development of a piezo-cantilever transducer and measuring method for evaluation of a temperature-sensitive polymer gel membrane

    Science.gov (United States)

    Li, Fenlan; Jiang, Zhongwei

    2007-06-01

    This paper is concerned with the development of a cantilever transducer patched with a piezoelectric element for evaluating the characteristics of a temperature-sensitive polymer gel membrane. The transducer consists of an aluminum cantilever beam patched with a piezoelectric ceramic and a probe coated by a polymer gel membrane. The probe can be easily attached to the cantilever transducer with double-sided sticky tape. The piezo-cantilever transducer is first simulated with the aid of a finite element method and the relation between the natural frequency change of the transducer and the absorbed mass on the polymer gel membrane is obtained theoretically. For measuring the temperature characteristics of the polymer gel membrane, the experiments are conducted in liquid and out of liquid. The temperature-sensitive poly(N-isopropylacrylamide) gel membrane hydrophilic-hydrophobic characteristics can be explained clearly by the results. Furthermore, two kinds of membrane coating method were proposed. The results indicate that the coating gel membrane has a better effect than the pasted gel membrane. The results also show that the piezo-cantilever transducer has a potential application for detecting polymer gel membrane characteristics conveniently and accurately.

  12. The 13C-excess: a new dual-element stable isotopic approach for detrending the effects of evaporation on lake carbonates

    Science.gov (United States)

    Horton, T. W.; Oze, C.

    2012-12-01

    Stable isotope-based proxy methods enhance our ability to interpret paleohydrology, paleoelevation, climate change, and biogeochemical cycles. In ancient carbonate lakes, these methods often require that the unmodified isotopic composition of meteoric water, or local carbon reservoirs, or both, are recorded by authigenic minerals. Surprisingly, these critical assumptions have not been tested across wide-ranging environmental contexts. Here, we show that globally distributed Quaternary lake carbonate oxygen isotope compositions are not strongly, nor significantly, correlated with local meteoric-derived water compositions due to the modification of in-flow waters following entry into the lake environment. These modifications are largely caused by surface water evaporation, and can result in dubious reconstructions of ancient hydrological conditions and water source effects such as the strength of prevailing air-mass trajectory, >3km errors in paleoelevation estimates, unrealistic shifts in lake water temperature, and misleading interpretations of local carbon cycle conditions if not accounted for. However, our analysis suggests that positive shifts in surface water δ18O are accompanied by similar magnitude shifts in δ13C-DIC during lake residence. This positive co-variation in δ18O and δ13C may be used to detrend lake carbonate compositions for the effects of surface water evaporation using a parameter we define here as the '13C-excess'. This approach uses the isotopic covariant trend between in-flow waters and lake waters, rather than lacustrine covariation alone, to better constrain ancient meteoric-derived water compositions. To demonstrate the potential strength of the 13C-excess approach over single element methods, we compare the paleoelevation estimates derived from lake carbonate compositions using both approaches. When Tibetan lakes are excluded from the dataset, 13C-excess values are significantly correlated with mean up-slope hypsometric altitude with

  13. Piezoelectric micromachined ultrasound transducer (PMUT) arrays for integrated sensing, actuation and imaging

    National Research Council Canada - National Science Library

    Qiu, Yongqiang; Gigliotti, James V; Wallace, Margeaux; Griggio, Flavio; Demore, Christine E M; Cochran, Sandy; Trolier-McKinstry, Susan

    2015-01-01

    .... Piezoelectric micromachined ultrasound transducers (PMUTs), diaphragm-like thin film flexural transducers typically formed on silicon substrates, are a potential solution for integrated transducer arrays...

  14. 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.)

  15. 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.

  16. QCD Dual

    DEFF Research Database (Denmark)

    Sannino, Francesco

    2009-01-01

    We uncover a novel solution of the 't Hooft anomaly matching conditions for QCD. Interestingly in the perturbative regime the new gauge theory, if interpreted as a possible QCD dual, predicts the critical number of flavors above which QCD in the nonperturbative regime, develops an infrared stable...... fixed point. Remarkably this value is identical to the maximum bound predicted in the nonpertubative regime via the all-orders conjectured beta function for nonsupersymmetric gauge theories.......We uncover a novel solution of the 't Hooft anomaly matching conditions for QCD. Interestingly in the perturbative regime the new gauge theory, if interpreted as a possible QCD dual, predicts the critical number of flavors above which QCD in the nonperturbative regime, develops an infrared stable...

  17. Aerial Triangulation Close-range Images with Dual Quaternion

    Directory of Open Access Journals (Sweden)

    SHENG Qinghong

    2015-05-01

    Full Text Available A new method for the aerial triangulation of close-range images based on dual quaternion is presented. Using dual quaternion to represent the spiral screw motion of the beam in the space, the real part of dual quaternion represents the angular elements of all the beams in the close-range area networks, the real part and the dual part of dual quaternion represents the line elements corporately. Finally, an aerial triangulation adjustment model based on dual quaternion is established, and the elements of interior orientation and exterior orientation and the object coordinates of the ground points are calculated. Real images and large attitude angle simulated images are selected to run the experiments of aerial triangulation. The experimental results show that the new method for the aerial triangulation of close-range images based on dual quaternion can obtain higher accuracy.

  18. On-chip RF-to-optical transducer

    DEFF Research Database (Denmark)

    Simonsen, Anders; Tsaturyan, Yeghishe; Seis, Yannick

    2016-01-01

    that engineering of the phononic density of states allows improved isolation of the relevant mechanical modes from their thermal bath [2], enabling coherence times sufficient to realize quantum-coherent optomechanical coupling. This proves the potential of the employed platform for complex transducers all the way...... motion and light, or phonons and photons. This interaction is the corner stone of the field of optomechanics and allows, for example, for ultrasensitive detection and manipulation of mechanical motion using laser light. Remarkably, today these techniques can be extended into the quantum regime, in which......Recent advances in the fabrication of nano- and micromechanical elements enable the realization of high-quality mechanical resonators with masses so small that the forces from optical photons can have a significant impact on their motion. This facilitates a strong interaction between mechanical...

  19. Ultrasonic characterization of a fluid layer using a broadband transducer.

    Science.gov (United States)

    Samet, Naïm; Maréchal, Pierre; Duflo, Hugues

    2012-03-01

    A measurement method is proposed for the ultrasonic characterization of a fluid layer, corresponding to the resin transfer molding (RTM) manufacturing process. The ultrasonic velocity and attenuation of the silicone oil are measured in three samples having different viscosities. The measurement method is established on the basis of the attenuation of ultrasonic waves in fluids. A correction of the beam diffraction is implemented to improve measurement precision. A single element transducer with central frequency of 15 MHz is used. The tested fluids simulate the industrial resin used to manufacture composite materials. When injecting this resin, its viscosity increases until it reaches a critical state of polymerization. In this paper we focus on ultrasonic characterization of three fluids representing three intermediate cases of fluid resin during its injection before reaching the polymerization state.

  20. Electromagnetic acoustic transducers noncontacting ultrasonic measurements using EMATS

    CERN Document Server

    Hirao, Masahiko

    2017-01-01

    This second edition provides comprehensive information on electromagnetic acoustic transducers (EMATs), from the theory and physical principles of EMATs to the construction of systems and their applications to scientific and industrial ultrasonic measurements on materials. The original version has been complemented with selected ideas on ultrasonic measurement that have emerged since the first edition was released. The book is divided into four parts: PART I offers a self-contained description of the basic elements of coupling mechanisms along with the practical designing of EMATs for various purposes. Several implementations to compensate for EMATs’ low transfer efficiency are provided, along with useful tips on how to make an EMAT. PART II describes the principle of electromagnetic acoustic resonance (EMAR), which makes the most of EMATs’ contactless nature and is the most successful amplification mechanism for precise measurements of velocity and attenuation. PART III applies EMAR to studying physical ...

  1. 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...

  2. Ultrasonic Transducer Fabricated Using Lead-Free BFO-BTO+Mn Piezoelectric 1-3 Composite

    Directory of Open Access Journals (Sweden)

    Yan Chen

    2015-05-01

    Full Text Available Mn-doped 0.7BiFeO3-0.3BaTiO3 (BFO-0.3BTO+Mn 1% mol lead-free piezoelectric ceramic were fabricated by traditional solid state reaction. The phase structure, microstructure, and ferroelectric properties were investigated. Additionally, lead-free 1–3 composites with 60% volume fraction of BFO-BTO+Mn ceramic were fabricated for ultrasonic transducer applications by a conventional dice-and-fill method. The BFO-BTO+Mn 1-3 composite has a higher electromechanical coupling coefficient (kt = 46.4% and lower acoustic impedance (Za ~ 18 MRayls compared with that of the ceramic. Based on this, lead-free piezoelectric ceramic composite, single element ultrasonic transducer with a center frequency of 2.54 MHz has been fabricated and characterized. The single element transducer exhibits good performance with a broad bandwidth of 53%. The insertion loss of the transducer was about 33.5 dB.

  3. Principle and experimental verification of novel dual driving face rotary ultrasonic motor

    Science.gov (United States)

    Lu, Xiaolong; Hu, Junhui; Yang, Lin; Zhao, Chunsheng

    2013-09-01

    Existing rotary ultrasonic motors operating in extreme environments cannot meet the requirements of good environmental adaptability and compact structure at same time, and existing ultrasonic motors with Langevin transducers show better environmental adaptability, but size of these motors are usually big due to the radial arrangement of the Langevin transducers. A novel dual driving face rotary ultrasonic motor is proposed, and its working principle is experimentally verified. The working principle of the novel ultrasonic motor is firstly proposed. The 5th in-plane flexural vibration travelling wave, excited by the Langevin transducers around the stator ring, is used to drive the rotors. Then the finite element method is used in the determination of dimensions of the prototype motor, and the confirmation of its working principle. After that, a laser Doppler vibrometer system is used for measuring the resonance frequency and vibration amplitude of the stator. At last, output characteristics of the prototype motor are measured, environmental adaptability is tested and performance for driving a metal ball is also investigated. At room temperature and 200 V(zero to peak) driving voltage, the motor’s no-load speed is 80 r/min, the stalling torque is 0.35 N·m and the maximum output power is 0.85 W. The response time of this motor is 0.96 ms at the room temperature, and it decreases or increases little in cold environment. A metal ball driven by the motor can rotate at 210 r/min with the driving voltage 300 V(zero to peak). Results indicate that the prototype motor has a large output torque and good environmental adaptability. A rotary ultrasonic motor owning compact structure and good environmental adaptability is proposed, and lays the foundations of ultrasonic motors’ applications in extreme environments.

  4. 21 CFR 890.1615 - Miniature pressure transducer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Miniature pressure transducer. 890.1615 Section 890.1615 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... Miniature pressure transducer. (a) Identification. A miniature pressure transducer is a device intended for...

  5. 21 CFR 868.2900 - Gas pressure transducer.

    Science.gov (United States)

    2010-04-01

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

  6. 21 CFR 868.2885 - Gas flow transducer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Gas flow transducer. 868.2885 Section 868.2885...) MEDICAL DEVICES ANESTHESIOLOGY DEVICES Monitoring Devices § 868.2885 Gas flow transducer. (a) Identification. A gas flow transducer is a device intended for medical purposes that is used to convert gas flow...

  7. 21 CFR 870.2870 - Catheter tip pressure transducer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Catheter tip pressure transducer. 870.2870 Section 870.2870 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... pressure transducer. (a) Identification. A catheter tip pressure transducer is a device incorporated into...

  8. 21 CFR 870.2840 - Apex cardiographic transducer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Apex cardiographic transducer. 870.2840 Section 870.2840 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... cardiographic transducer. (a) Identification. An apex cardiographic transducer is a device used to detect motion...

  9. 21 CFR 868.2875 - Differential pressure transducer.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Differential pressure transducer. 868.2875 Section 868.2875 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... transducer. (a) Identification. A differential pressure transducer is a two-chambered device intended for...

  10. New technique for fabrication of high frequency piezoelectric Micromachined Ultrasound Transducers

    DEFF Research Database (Denmark)

    Pedersen, T; Thomsen, Erik Vilain; Zawada, T

    2008-01-01

    A novel technique for fabrication of linear arrays of high frequency piezoelectric Micromachined Ultrasound Transducers (pMUT) on silicon substrates is presented. Piezoelectric elements are formed by deposition of PZT ((PbZrxTi1-x)O3) into etched features of the silicon substrate...... such that the depth of these features determine the element thickness and hence the resonance frequency. The process leaves a near planar surface which is ideal for further wafer level processing such as top electrode and interconnect formation. A fabricated single element is characterized by pulse echo response....

  11. 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.

  12. 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.

  13. 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.

  14. 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.

  15. Hybrid neural network models of transducers

    Science.gov (United States)

    Xie, Shilin; Zhang, Xinong; Chen, Shenglai; Zhu, Changchun

    2011-10-01

    A hybrid neural network (NN) approach is proposed and applied to modeling of transducers in the paper. The modeling procedures are also presented in detail. First, the simulated studies on the modeling of single input-single output and multi input-multi output transducers are conducted respectively by use of the developed hybrid NN scheme. Secondly, the hybrid NN modeling approach is utilized to characterize a six-axis force sensor prototype based on the measured data. The results show that the hybrid NN approach can significantly improve modeling precision in comparison with the conventional modeling method. In addition, the method is superior to NN black-box modeling because the former possesses smaller network scale, higher convergence speed, higher model precision and better generalization performance.

  16. 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...

  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. Transducer Arrays Suitable for Acoustic Imaging

    Science.gov (United States)

    1978-06-01

    extensional resonance of a thin plate. The stif- fened velocity and acoustic im.pedance of the transducer can be defined then as follows: ,,,D 1/2 󈧥 (3...finite radius performing rotaticnal oscillations about its center. Case (a) is identical to the cne evaluated in this pape-. The integrals in...Poisson’s ratio. For (k.L) > I , the impedance is essen- tially real and oscillates slowly about the longitudinal plane wave impedance. Below (k,L) = 1

  19. 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)

  20. 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.

  1. 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.

  2. THE DUAL MIXED METHOD FOR AN UNILATERAL PROBLEM

    Institute of Scientific and Technical Information of China (English)

    Lie-heng Wang

    2003-01-01

    In this paper, the dual mixed method for an unilateral problems which is the simplified modelling of scalar function for the friction-free contact problem, is considered. The dual mixed problem is introduced, the existence and uniqeness of the solution of the problem are presented, and error bounds O(h4/3) and O(h2/3) are obtained for the dual mixed finite element approximations of Raviart-Thomas elements for k = 0 and k = 1 respectively.

  3. 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

  4. 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.

  5. New mitral annular force transducer optimized to distinguish annular segments and multi-plane forces.

    Science.gov (United States)

    Skov, Søren Nielsen; Røpcke, Diana Mathilde; Ilkjær, Christine; Rasmussen, Jonas; Tjørnild, Marcell Juan; Jimenez, Jorge H; Yoganathan, Ajit P; Nygaard, Hans; Nielsen, Sten Lyager; Jensen, Morten Olgaard

    2016-03-21

    Limited knowledge exists about the forces acting on mitral valve annuloplasty repair devices. The aim of this study was to develop a new mitral annular force transducer to measure the forces acting on clinically used mitral valve annuloplasty devices. The design of an X-shaped transducer in the present study was optimized for simultaneous in- and out-of-plane force measurements. Each arm was mounted with strain gauges on four circumferential elements to measure out-of-plane forces, and the central parts of the X-arms were mounted with two strain gauges to measure in-plane forces. A dedicated calibration setup was developed to calibrate isolated forces with tension and compression for in- and out-of-plane measurements. With this setup, it was possible with linear equations to isolate and distinguish measured forces between the two planes and minimize transducer arm crosstalk. An in-vitro test was performed to verify the crosstalk elimination method and the assumptions behind it. The force transducer was implanted and evaluated in an 80kg porcine in-vivo model. Following crosstalk elimination, in-plane systolic force accumulation was found to be in average 4.0±0.1N and the out-of-plane annular segments experienced an average force of 1.4±0.4N. Directions of the systolic out-of-plane forces indicated movements towards a saddle shaped annulus, and the transducer was able to measure independent directional forces in individual annular segments. Further measurements with the new transducer coupled with clinical annuloplasty rings will provide a detailed insight into the biomechanical dynamics of these devices.

  6. The Effects of Piezoelectric Ceramic Dissipation Factor on the Performance of Ultrasonic Transducers

    Science.gov (United States)

    DeAngelis, D. A.; Schulze, G. W.

    The dissipation factor (DF) is an important material property of piezoceramics that governs the amount of self-heating under resonant conditions; it essentially quantifies a particular material type for either an actuator or resonator application: high DF materials with typically higher output (d33) are better for actuators, whereas low DF materials with typically lower d33 are better for resonators. Transducer designers must often compromise between mechanical output and DF in the selection of piezoceramics for power ultrasonic applications, and abnormally high DF is one of the main causes of production stoppages. In theory DF is simply the current/voltage phase deviation from an ideal capacitor at 90° (a.k.a. tan(δ) or dielectric loss). Abnormally high DF is typically caused by moisture absorption due to poor ceramic porosity, which causes voltage leakage effects; e.g., seen in transducer production when setting piezo stack preload. Corresponding large increases in capacitance can also be associated with poor porosity, which is counterintuitive unless there is moisture absorption or electrode wicking. This research investigates the mechanisms for abnormally high DF in peizoceramics, and its corresponding effect on transducer performance. It investigates if DF is only affected by the bulk dielectric properties of the piezoceramics (e.g. porosity), or is also influenced by non-uniform electric field effects from electrode wicking. It explores if higher DF ceramics can affect transducer displacement/current gain stability via moisture expulsion at higher drive levels. The investigation focuses solely on the common PZT8 piezoelectric material used with welding transducers for semiconductor wire bonding. Transducers are built with both normal DF peizoceramics, and those with abnormally high DF ceramics which caused production stoppages. Several metrics are investigated such as impedance, displacement gain and capacitance. The experimental and theoretical research

  7. A 3D reconstruction algorithm for magneto-acoustic tomography with magnetic induction based on ultrasound transducer characteristics

    Science.gov (United States)

    Ma, Ren; Zhou, Xiaoqing; Zhang, Shunqi; Yin, Tao; Liu, Zhipeng

    2016-12-01

    In this study we present a three-dimensional (3D) reconstruction algorithm for magneto-acoustic tomography with magnetic induction (MAT-MI) based on the characteristics of the ultrasound transducer. The algorithm is investigated to solve the blur problem of the MAT-MI acoustic source image, which is caused by the ultrasound transducer and the scanning geometry. First, we established a transducer model matrix using measured data from the real transducer. With reference to the S-L model used in the computed tomography algorithm, a 3D phantom model of electrical conductivity is set up. Both sphere scanning and cylinder scanning geometries are adopted in the computer simulation. Then, using finite element analysis, the distribution of the eddy current and the acoustic source as well as the acoustic pressure can be obtained with the transducer model matrix. Next, using singular value decomposition, the inverse transducer model matrix together with the reconstruction algorithm are worked out. The acoustic source and the conductivity images are reconstructed using the proposed algorithm. Comparisons between an ideal point transducer and the realistic transducer are made to evaluate the algorithms. Finally, an experiment is performed using a graphite phantom. We found that images of the acoustic source reconstructed using the proposed algorithm are a better match than those using the previous one, the correlation coefficient of sphere scanning geometry is 98.49% and that of cylinder scanning geometry is 94.96%. Comparison between the ideal point transducer and the realistic transducer shows that the correlation coefficients are 90.2% in sphere scanning geometry and 86.35% in cylinder scanning geometry. The reconstruction of the graphite phantom experiment also shows a higher resolution using the proposed algorithm. We conclude that the proposed reconstruction algorithm, which considers the characteristics of the transducer, can obviously improve the resolution of the

  8. CMOS circuits for electromagnetic vibration transducers interfaces for ultra-low voltage energy harvesting

    CERN Document Server

    Maurath, Dominic

    2015-01-01

    Chip-integrated power management solutions are a must for ultra-low power systems. This enables not only the optimization of innovative sensor applications. It is also essential for integration and miniaturization of energy harvesting supply strategies of portable and autonomous monitoring systems. The book particularly addresses interfaces for energy harvesting, which are the key element to connect micro transducers to energy storage elements. Main features of the book are: - A comprehensive technology and application review, basics on transducer mechanics, fundamental circuit and control design, prototyping and testing, up to sensor system supply and applications. - Novel interfacing concepts - including active rectifiers, MPPT methods for efficient tracking of DC as well as AC sources, and a fully-integrated charge pump for efficient maximum AC power tracking at sub-100µW ultra-low power levels. The chips achieve one of widest presented operational voltage range in standard CMOS technology: 0.44V to over...

  9. Capacitive Micromachined Ultrasonic Transducer Arrays for Integrated Diagnostic/Therapeutic Catheters

    Science.gov (United States)

    Wong, Serena H.; Wygant, Ira O.; Yeh, David T.; Zhuang, Xuefeng; Bayram, Baris; Kupnik, Mario; Oralkan, Omer; Ergun, A. Sanli; Yaralioglu, Goksen G.; Khuri-Yakub, Butrus T.

    2006-05-01

    In recent years, medical procedures have become increasingly non-invasive. These include endoscopic procedures and intracardiac interventions (e.g., pulmonary vein isolation for treatment of atrial fibrillation and plaque ablation for treatment of arteriosclerosis). However, current tools suffer from poor visualization and difficult coordination of multiple therapeutic and imaging devices. Dual-mode (imaging and therapeutic) ultrasound arrays provide a solution to these challenges. A dual-mode transducer can provide focused, noncontact ultrasound suitable for therapy and can be used to provide high quality real-time images for navigation and monitoring of the procedure. In the last decade, capacitive micromachined ultrasonic transducers (CMUTs), have become an attractive option for ultrasonic imaging systems due to their fabrication flexibility, improved bandwidth, and integration with electronics. The CMUT's potential in therapeutic applications has also been demonstrated by surface output pressures as high as 1MPa peak to peak and continuous wave (CW) operation. This paper reviews existing interventional CMUT arrays, demonstrates the feasibility of CMUTs for high intensity focused ultrasound (HIFU), and presents a design for the next-generation CMUTs for integrated imaging and HIFU endoscopic catheters.

  10. Theoretical Calculation of a Focused Acoustic Field from a Linear Phased Array on a Concave Cylindrical Transducer

    Institute of Scientific and Technical Information of China (English)

    YU Li-Li; SHOU Wen-De; HUI Chun

    2011-01-01

    A new linear phased array on a concave cylindrical transducer is designed for meeting the specific requirements of applications for interstitial thermal ablation. Using the array, a focal line can be generated rapidly and the focal position can be adjusted in the proper range without the use of complex mechanical structures. The focused acoustic Reid distributions in the axial, radial and azimuthal directions of the transducer are investigated theoretically by numerical simulation. Effects of the focal distance, steering angle, element arc-width, arc-space between adjacent elements and number of elements on the acoustic field are also thoroughly studied. Many important results are obtained.%A new linear phased array on a concave cylindrical transducer is designed for meeting the specific requirements of applications for interstitial thermal ablation.Using the array,a focal line can be generated rapidly and the focal position can be adjusted in the proper range without the use of complex mechanical structures.The focused acoustic field distributions in the axial,radial and azimuthal directions of the transducer are investigated theoretically by numerical simulation.Effects of the focai distance,steering angle,element arc-width,arc-space between adjacent elements and number of elements on the acoustic field are also thoroughly studied.Many important results are obtained.Interstitial thermal ablation is a promising technique for treating tumors that are both nonresectable and difficult to reach with extracorporeal therapy.[1,2] In this method,a small transducer is brought into contact with the targeted region and emits a highintensity acoustic wave;the interaction between the wave and the tissues causes a strong heating effect that induces the thermal coagulation and necrosis of the target.[3

  11. High-Temperature Surface-Acoustic-Wave Transducer

    Science.gov (United States)

    Zhao, Xiaoliang; Tittmann, Bernhard R.

    2010-01-01

    Aircraft-engine rotating equipment usually operates at high temperature and stress. Non-invasive inspection of microcracks in those components poses a challenge for the non-destructive evaluation community. A low-profile ultrasonic guided wave sensor can detect cracks in situ. The key feature of the sensor is that it should withstand high temperatures and excite strong surface wave energy to inspect surface/subsurface cracks. As far as the innovators know at the time of this reporting, there is no existing sensor that is mounted to the rotor disks for crack inspection; the most often used technology includes fluorescent penetrant inspection or eddy-current probes for disassembled part inspection. An efficient, high-temperature, low-profile surface acoustic wave transducer design has been identified and tested for nondestructive evaluation of structures or materials. The development is a Sol-Gel bismuth titanate-based surface-acoustic-wave (SAW) sensor that can generate efficient surface acoustic waves for crack inspection. The produced sensor is very thin (submillimeter), and can generate surface waves up to 540 C. Finite element analysis of the SAW transducer design was performed to predict the sensor behavior, and experimental studies confirmed the results. One major uniqueness of the Sol-Gel bismuth titanate SAW sensor is that it is easy to implement to structures of various shapes. With a spray coating process, the sensor can be applied to surfaces of large curvatures. Second, the sensor is very thin (as a coating) and has very minimal effect on airflow or rotating equipment imbalance. Third, it can withstand temperatures up to 530 C, which is very useful for engine applications where high temperature is an issue.

  12. Effects of adhesive, host plate, transducer and excitation parameters on time reversibility of ultrasonic Lamb waves.

    Science.gov (United States)

    Agrahari, J K; Kapuria, S

    2016-08-01

    To develop an effective baseline-free damage detection strategy using the time-reversal process (TRP) of Lamb waves in thin walled structures, it is essential to develop a good understanding of the parameters that affect the amplitude dispersion and consequently the time reversibility of the Lamb wave signal. In this paper, the effects of adhesive layer between the transducers and the host plate, the tone burst count of the excitation signal, the plate thickness, and the piezoelectric transducer thickness on the time reversibility of Lamb waves in metallic plates are studied using experiments and finite element simulations. The effect of adhesive layer on the forward propagation response and frequency tuning has been also studied. The results show that contrary to the general expectation, the quality of the reconstruction of the input signal after the TRP may increase with the increase in the adhesive layer thickness at certain frequency ranges. Similarly, an increase in the tone burst count resulting in a narrowband signal does not necessarily enhance the time reversibility at all frequencies, contrary to what has been reported earlier. For a given plate thickness, a thinner transducer yields a better reconstruction, but for a given transducer thickness, the similarity of the reconstructed signal may not be always higher for a thicker plate. It is important to study these effects to achieve the best quality of reconstruction in undamaged plates, for effective damage detection.

  13. Trapping of microparticles in the near field of an ultrasonic transducer.

    Science.gov (United States)

    Lilliehorn, Tobias; Simu, Urban; Nilsson, Mikael; Almqvist, Monica; Stepinski, Tadeusz; Laurell, Thomas; Nilsson, Johan; Johansson, Stefan

    2005-03-01

    We are investigating means of handling microparticles in microfluidic systems, in particular localized acoustic trapping of microparticles in a flow-through device. Standing ultrasonic waves were generated across a microfluidic channel by ultrasonic microtransducers integrated in one of the channel walls. Particles in a fluid passing a transducer were drawn to pressure minima in the acoustic field, thereby being trapped and confined at the lateral position of the transducer. The spatial distribution of trapped particles was evaluated and compared with calculated acoustic intensity distributions. The particle trapping was found to be strongly affected by near field pressure variations due to diffraction effects associated with the finite sized transducer element. Since laterally confining radiation forces are proportional to gradients in the acoustic energy density, these near field pressure variations may be used to get strong trapping forces, thus increasing the lateral trapping efficiency of the device. In the experiments, particles were successfully trapped in linear fluid flow rates up to 1mm/s. It is anticipated that acoustic trapping using integrated transducers can be exploited in miniaturised total chemical analysis systems (microTAS), where e.g. microbeads with immobilised antibodies can be trapped in arrays and subjected to minute amounts of sample followed by a reaction, detected using fluorescence.

  14. Optimization of acoustic emitted field of transducer array for ultrasound imaging.

    Science.gov (United States)

    He, Zhengyao

    2014-01-01

    A method is proposed to calculate the weight vector of a transducer array for ultrasound imaging to obtain a low-sidelobe transmitting beam pattern based on the near-field response vector. An optimization problem is established, and the second-order cone (SOC) algorithm is used to solve the problem to obtain the weight vector. The optimized acoustic emitted field of the transducer array is then calculated using the Field II program by applying the obtained weight vector to the array. The simulation results with a 64-element 26 MHz linear phased array show that the proposed method can be used to control the sidelobe of the near-field transmitting beam pattern of the transducer array and achieve a low-sidelobe level. The near-field sound pressure distribution of the transducer array using the proposed method focuses much better than that using the standard delay and sum (DAS) beamforming method. The sound energy is more concentrated using the proposed method.

  15. Ultrasound transducer function: annual testing is not sufficient.

    Science.gov (United States)

    Mårtensson, Mattias; Olsson, Mats; Brodin, Lars-Åke

    2010-10-01

    The objective was to follow-up the study 'High incidence of defective ultrasound transducers in use in routine clinical practice' and evaluate if annual testing is good enough to reduce the incidence of defective ultrasound transducers in routine clinical practice to an acceptable level. A total of 299 transducers were tested in 13 clinics at five hospitals in the Stockholm area. Approximately 7000-15,000 ultrasound examinations are carried out at these clinics every year. The transducers tested in the study had been tested and classified as fully operational 1 year before and since then been in normal use in the routine clinical practice. The transducers were tested with the Sonora FirstCall Test System. There were 81 (27.1%) defective transducers found; giving a 95% confidence interval ranging from 22.1 to 32.1%. The most common transducer errors were 'delamination' of the ultrasound lens and 'break in the cable' which together constituted 82.7% of all transducer errors found. The highest error rate was found at the radiological clinics with a mean error rate of 36.0%. There was a significant difference in error rate between two observed ways the clinics handled the transducers. There was no significant difference in the error rates of the transducer brands or the transducers models. Annual testing is not sufficient to reduce the incidence of defective ultrasound transducers in routine clinical practice to an acceptable level and it is strongly advisable to create a user routine that minimizes the handling of the transducers.

  16. 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

  17. 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.

  18. Quantum dot coating of baculoviral vectors enables visualization of transduced cells and tissues

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Ying; Lo, Seong Loong [Institute of Bioengineering and Nanotechnology, Singapore (Singapore); Zheng, Yuangang [Institute of Materials Research and Engineering, Singapore (Singapore); Lam, Dang Hoang [Institute of Bioengineering and Nanotechnology, Singapore (Singapore); Department of Biological Sciences, National University of Singapore, Singapore (Singapore); Wu, Chunxiao [Institute of Bioengineering and Nanotechnology, Singapore (Singapore); Han, Ming Yong [Institute of Materials Research and Engineering, Singapore (Singapore); Wang, Shu, E-mail: dbsws@nus.edu.sg [Institute of Bioengineering and Nanotechnology, Singapore (Singapore); Department of Biological Sciences, National University of Singapore, Singapore (Singapore)

    2013-04-26

    Highlights: •The use of quantum dot (QD)-labeled viral vectors for in vivo imaging is not well investigated. •A new method to label enveloped baculovirus with glutathione-capped CdTe QDs is developed. •The labeling enables the identification of transduced, cultured cells based on fluorescence. •The labeling also allows evaluation of viral transduction in a real-time manner in living mice. •The method has the potential to assess viral vector-based gene therapy protocols in future. -- Abstract: Imaging of transduced cells and tissues is valuable in developing gene transfer vectors and evaluating gene therapy efficacy. We report here a simple method to use bright and photostable quantum dots to label baculovirus, an emerging gene therapy vector. The labeling was achieved through the non-covalent interaction of glutathione-capped CdTe quantum dots with the virus envelope, without the use of chemical conjugation. The quantum dot labeling was nondestructive to viral transduction function and enabled the identification of baculoviral vector-transduced, living cells based on red fluorescence. When the labeled baculoviral vectors were injected intravenously or intraventricularly for in vivo delivery of a transgene into mice, quantum dot fluorescence signals allow us monitor whether or not the injected tissues were transduced. More importantly, using a dual-color whole-body imaging technology, we demonstrated that in vivo viral transduction could be evaluated in a real-time manner in living mice. Thus, our method of labeling a read-to-use gene delivery vector with quantum dots could be useful towards the improvement of vector design and will have the potential to assess baculovirus-based gene therapy protocols in future.

  19. Evaluation of a novel therapeutic focused ultrasound transducer based on Fermat’s spiral

    Science.gov (United States)

    Ramaekers, P.; de Greef, M.; Berriet, R.; Moonen, C. T. W.; Ries, M.

    2017-06-01

    The purpose of this study was to evaluate a novel phased array transducer design rule for therapeutic focused ultrasound applications. This design rule uses the discretized Fermat’s spiral to determine the positioning of the transducer elements for a given number of elements and f-number. Using this principle, three variations of Fermat’s spiral were generated, aimed at (1) grating lobe minimization, (2) side lobe minimization, and (3) an optimized element packing efficiency. For each spiral, sparse layouts using identical circular elements and fully populated layouts based on additional Voronoi tessellation were evaluated numerically. Evaluation criteria included the element size distribution, beam steering capabilities, focal plane pressure distribution, prefocal pressure distribution, and practical considerations. Finally, one Voronoi-tessellated design with a focal length and aperture diameter of 16 cm and a natural frequency of 1.3 MHz was evaluated experimentally through hydrophone measurements. The numerical evaluation showed that while sparse arrays possess superior beam steering capabilities for a given number of elements, the focal point quality and prefocal pressure distribution is substantially more favorable when using the Voronoi-tessellated designs. Beam steering was shown to be feasible with the tessellated designs for lateral deflections up to 10 mm and axial deflections up to 20 mm. The experimental evaluation showed that such a transducer is capable of inducing 40.00 MPa rarefactional and 237.50 MPa compressional peak pressure levels at 800 W instantaneous acoustic output power under free-field conditions, making the system potentially relevant for thermal ablation therapy, histotripsy applications, and shockwave-enhanced heating.

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

    Science.gov (United States)

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

    2016-01-01

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

  1. 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.

  2. Experimental researches of laser phase lock with dual-servo feedbacks based on the piezoelectric transducer and fiber electrooptic phase modulator%基于压电陶瓷与光纤电光调制器双通道伺服反馈的激光相位锁定实验研究∗

    Institute of Scientific and Technical Information of China (English)

    侯佳佳; 尹王保; 肖连团; 贾锁堂; 赵刚; 谭巍; 邱晓东; 贾梦源; 马维光; 张雷; 董磊; 冯晓霞

    2016-01-01

    Fiber laser can be used for fiber optic communications, laser cutting, industrial manufacture, defense security and many other fields because of its advantages of narrow output linewidth, good reproducibility, etc. However, due to nonlinear and thermal effects, only a limited output power of a single fiber can be obtained with a sharp attenuation of the output beam quality, which obstructs the applications of fiber lasers. Therefore, the research of expanding the power of a fiber laser source while maintaining its beam quality by combining coherent beam has become a hot subject at present. In this field, the performance of phase control of coherent laser beams is a key factor to influence the efficiency of combination. The phase-controlling methods mainly include stochastic parallel gradient descent control algorithm, dithering, and heterodyne detection. In this paper, based on the active phase lock technology, the traditional heterodyne detection method is improved by the use of a fiber electro-optic phase modulator (EOM) rather than an acousto-optic frequency shifter (AOFS) to avoid the complex designs of the RF driver and circuit, which makes the overall experimental setup simple and stable. Moreover, in order to achieve a stable and wide correction range of phase locking, two servo paths are designed by use of piezoelectric transducer (PZT) and EOM1 to correct the optical phase differences. Firstly, a single-frequency narrow-width fiber laser with its central wavelength of 1531 nm is split by a beam splitter to generate a signal and a reference beam, respectively. The reference beam is phase modulated by another EOM2 with a 15 MHz signal. The phase error signal is obtained by demodulating the detected heterodyne signal at the modulation frequency. After that the error signal is divided into two parts, and sent to two PID servos to control PZT and EOM1, respectively. The PZT, used in the slow feedback loop, eliminates the laser phase error induced by the ambient

  3. 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...

  4. 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...

  5. Dual Lattice of ℤ-module Lattice

    Directory of Open Access Journals (Sweden)

    Futa Yuichi

    2017-07-01

    Full Text Available In this article, we formalize in Mizar [5] the definition of dual lattice and their properties. We formally prove that a set of all dual vectors in a rational lattice has the construction of a lattice. We show that a dual basis can be calculated by elements of an inverse of the Gram Matrix. We also formalize a summation of inner products and their properties. Lattice of ℤ-module is necessary for lattice problems, LLL(Lenstra, Lenstra and Lovász base reduction algorithm and cryptographic systems with lattice [20], [10] and [19].

  6. Design and Test of Capacitive Micromachined Ultrasonic Transducer

    National Research Council Canada - National Science Library

    Hongliang Wang; Xiangjun Wang; Changde He; Chenyang Xue; Jijun Xiong; Wendong Zhang; Jing Miao; Yuping Li

    2014-01-01

      Currently, most capacitive micromachined ultrasound transducers, adopting surface sacrificial technology encounter various problems such as difficult cavity etch, low controllability of membrane thickness etc...

  7. 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.

  8. 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.

  9. 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.

  10. 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...

  11. 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.

  12. Analysis of annular phased array transducers for ultrasonic guided wave mode control

    Science.gov (United States)

    Kannajosyula, H.; Lissenden, C. J.; Rose, J. L.

    2013-08-01

    Exact and asymptotic analyses of annular phased array transducers (PAT) for elastic guided wave mode selection are presented. For the purpose of analysis, the transducer-substrate interaction is formulated in terms of a three-dimensional analogy to filters as applied one-dimensionally in areas such as signal processing and control theory. This enables the deduction of most of the properties of the annular array purely from the Fourier analysis of any actuating function that represents the loading due to the transducer. A generalized mathematical model of the actuating function due to the annular PAT is constructed. The Fourier spectrum is analyzed for resonances in the wavenumber domain. Formulas for phase and time delays are presented. The phenomena of outgoing and incoming waves are also studied. Numerical analysis of the wavenumber spectrum for the annular PAT with a finite number of elements is performed to further illustrate the results deduced from exact and asymptotic analyses. Finite element simulations are presented to further verify the phenomena predicted through the wavenumber spectrum analysis.

  13. An omnidirectional shear horizontal wave transducer based on ring array of face-shear (d24) piezoelectric ceramics

    CERN Document Server

    Miao, Hongchen; Wang, Qiangzhong; Li, Faxin

    2016-01-01

    The non-dispersive fundamental shear horizontal (SH0) wave in plate-like structures is of practical importance in non-destructive testing (NDT) and structural health monitoring (SHM). Theoretically, an omnidirectional SH0 transducer phased array system can be used to inspect defects in a large plate in the similar manner to the phased array transducers used in medical B-scan ultrasonics. However, very few omnidirectional SH transducers have been proposed so far. In this work, an omnidirectional SH wave piezoelectric transducer (OSH-PT) was proposed which consists of a ring array of twelve face-shear (d24) trapezoidal PZT elements. Each PZT element can produce face-shear deformation under applied voltage, resulting in circumferential shear deformation in the OSH-PT and omnidirectional SH waves in the hosting plate. Both finite element simulations and experiments were conducted to examine the performance of the proposed OSH-PT. Experimental testing shows that the OSH-PT exhibits good omnidirectional properties,...

  14. 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.

  15. Materials issues in high temperature ultrasonic transducers for under-sodium viewing

    Science.gov (United States)

    Bond, L. J.; Griffin, J. W.; Posakony, G. J.; Harris, R. V.; Baldwin, D. L.

    2012-05-01

    Liquid sodium is used as the coolant in some fast spectrum nuclear reactors. This material is optically opaque. To facilitate operations and maintenance activities, an ultrasonic under-sodium viewing system has been developed. In the USA, the technology was successfully demonstrated in the 1970s and, over the intervening 30+ years, the capability was lost. This paper reports materials challenges encountered in developing both single-element and linear phased-array 2-MHz transducers that must operate at temperatures up to 260°C. The critical issues are fundamentally material selection: the ability of a transducer to be immersed into liquid sodium and function at 260°C, to achieve wetting and transmission of ultrasound into the sodium, and to be able to be removed and re-used.

  16. An FPGA-based ultrasound imaging system using capacitive micromachined ultrasonic transducers.

    Science.gov (United States)

    Wong, Lawrence L P; Chen, Albert I; Logan, Andrew S; Yeow, John T W

    2012-07-01

    We report the design and experimental results of a field-programmable gate array (FPGA)-based real-time ultrasound imaging system that uses a 16-element phased-array capacitive micromachined ultrasonic transducer fabricated using a fusion bonding process. The imaging system consists of the transducer, discrete analog components situated on a custom-made circuit board, the FPGA, and a monitor. The FPGA program consists of five functional blocks: a main counter, transmit and receive beamformer, receive signal pre-processing, envelope detection, and display. No dedicated digital signal processor or personal computer is required for the imaging system. An experiment is carried out to obtain the sector B-scan of a 4-wire target. The ultrasound imaging system demonstrates the possibility of an integrated system-in-a-package solution.

  17. Optimization Design Method for the CMOS-type Capacitive Micro-Machined Ultrasonic Transducer

    Directory of Open Access Journals (Sweden)

    D. Y. Chiou

    2011-12-01

    Full Text Available In this study, an integrated modeling technique for characterization and optimization design of the complementary metal-oxide-semiconductor (CMOS capacitive micro-arrayed ultrasonic transducer (pCMOS-CMUT is presented. Electromechanical finite element simulations are performed to investigate its operational characteristics, such as the collapse voltage and the resonant frequency. Both the numerical and experimental results are in good agreement. In order to simultaneously customize the resonant frequency and minimize the collapse voltage, the genetic algorithm (GA is applied to optimize dimensional parameters of the transducer. From the present results, it is concluded that the FE/GA coupling approach provides another efficient numerical tool for multi-objective design of the pCMOS-CMUT.

  18. Magnetoelastic Transducer Materials - a Plateable Possibility

    DEFF Research Database (Denmark)

    Jensen, Jens Dahl; Møller, Per

    2001-01-01

    A short presentation of the magnetostriction theory as well as a series of possible applications for magnetoelastic transducers are given. A review of the present state of development for these materials is discussed with relation to the various ways of manufacture. The paper is concluded...... with the presentation of a method for making magnetoelastic materials by electrochemical deposition (electroless) as tried by the authors in collaboration with the Daimler-Chrysler research centre in Ulm, Germany. First results of this work are both promising and intriguing: Sensitivities of the same order...... as the reference material Terfenol-D were obtained, but reproduction of exact magnetic properties is still critical with the new plating technique....

  19. Multicavity Janus-Helmholtz underwater acoustic transducer%多液腔Janus-Helmholtz水声换能器

    Institute of Scientific and Technical Information of China (English)

    桑永杰; 蓝宇

    2013-01-01

    In order to expand the operating bandwidth of the Janus-Helmholtz transducer, a multicavity Janus-Helm-holtz transducer was presented,and the structure parameters of the multicavity Janus-Helmholtz transducer were op-timized by the finite element method. A multicavity Janus-Helmholtz transducer experiment prototype was produced on basis of the optimization results. The test result shows that, the simulation results agree with the experimental re-sult. Compared to the traditional Janus-Helmholtz transducer, the multicavity Janus-Helmholtz transducer may effec-tively expand the operating bandwidth, it is an ideal low-frequency, broadband, high-power, small-size, and deep-water transducer.%为了进一步拓展Janus-Helmholtz换能器的工作带宽,提出一种多液腔Janus-Helmholtz换能器结构,采用有限元的方法对多液腔Janus-Helmholtz换能器的结构参数进行优化设计。依据优化结果制作了一个多液腔Janus-Helmholtz换能器试验样机。测试结果显示,仿真结果和实验结果基本相符。相比传统的Janus-Helmholtz换能器,多液腔Janus-Helm-holtz换能器可有效地拓展工作带宽,是一种理想的低频、宽带、大功率、小体积、深水换能器。

  20. 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.

  1. 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.

  2. 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 Simulat...

  3. 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 Simul...

  4. 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,…

  5. 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...

  6. 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,…

  7. 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…

  8. Ultrasonic transducer with thermomechanical excitation and piezoresistive detection

    NARCIS (Netherlands)

    Popescu, Dan S.; Dascalu, Dan C.; Elwenspoek, Michael Curt; Lammerink, Theodorus S.J.

    1996-01-01

    Ultrasonic transducer was fabricated from silicon buckled membrane using a thermo mechanical excitation and piezoresistive detection. The transducer has a 4 mm square silicon membrane, buckled with an initial deflection of 20μm, actuated by dynamically heating an aluminium ring layer, 3μm thick, wit

  9. 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…

  10. Top-down tree transducers with regular look-ahead

    NARCIS (Netherlands)

    Engelfriet, Joost

    1977-01-01

    Top-down tree transducers with regular look-ahead are introduced. It is shown how these can be decomposed and composed, and how this leads to closure properties of surface sets and tree transformation languages. Particular attention is paid to deterministic tree transducers.

  11. 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.

  12. 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.

  13. Modelling and Numerical Simulations of In-Air Reverberation Images for Fault Detection in Medical Ultrasonic Transducers: A Feasibility Study

    Directory of Open Access Journals (Sweden)

    W. Kochański

    2015-01-01

    Full Text Available A simplified two-dimensional finite element model which simulates the in-air reverberation image produced by medical ultrasonic transducers has been developed. The model simulates a linear array consisting of 128 PZT-5A crystals, a tungsten-epoxy backing layer, an Araldite matching layer, and a Perspex lens layer. The thickness of the crystal layer is chosen to simulate pulses centered at 4 MHz. The model is used to investigate whether changes in the electromechanical properties of the individual transducer layers (backing layer, crystal layer, matching layer, and lens layer have an effect on the simulated in-air reverberation image generated. Changes in the electromechanical properties are designed to simulate typical medical transducer faults such as crystal drop-out, lens delamination, and deterioration in piezoelectric efficiency. The simulations demonstrate that fault-related changes in transducer behaviour can be observed in the simulated in-air reverberation image pattern. This exploratory approach may help to provide insight into deterioration in transducer performance and help with early detection of faults.

  14. Transducer hygiene: comparison of procedures for decontamination of ultrasound transducers and their use in clinical practice.

    Science.gov (United States)

    Häggström, Mikael; Spira, Jack; Edelstam, Greta

    2015-02-01

    To determine whether current hygiene practices are appropriate during sonographic examinations. Five major hospitals in Sweden were investigated with a survey. At each hospital, the departments corresponding to the main types of sonographic examination were chosen. Personnel who were responsible for or acquainted with the local hygiene procedures completed a standardardized questionnaire. The surveys were completed by 25 departments, where the total number of sonographic examinations was approximately 20,000 per month. For transvaginal and transrectal sonographic examinations, the most common method for decontamination of the transducer was barrier protection during the procedure followed by cleansing with alcohol. Latex was the predominant cover material, but one department used polyethylene gloves, and another department used nitrile gloves. Both of these involved transvaginal ultrasonography. In transcutaneous examinations, all hospitals were using alcohol and paper or cloth for decontamination at a minimum. Transesophageal examinations were carried out without barrier protection, and decontamination was performed with an alkylating substance. The hygiene practices appear to be appropriate at most hospitals, but there is a prevalence of transducer cover materials of unacceptable permeability, as well as use of gloves on transducers despite insufficient evidence of safety. © 2015 Wiley Periodicals, Inc.

  15. A new rotary ultrasonic motor using longitudinal vibration transducers

    Directory of Open Access Journals (Sweden)

    Xiangyu Zhou

    2015-05-01

    Full Text Available To simplify the design process and improve the motor performance, a rotary ultrasonic motor with rotationally symmetrical structure has been designed, fabricated, and characterized. The stator consists of four connected sandwich-type transducers and eight driving feet. The rotor, a disk, and a disk-shaft are pressed on the two sides of the stator by a nut–spring system. To drive the rotor, two orthogonal longitudinal vibration modes of the stator should be excited. The operating principle of the rotary motor was analyzed by a mathematical model. By using finite element analysis, the feasibility of the operating principle was validated, and the optimal structure dimensions of stator were determined in order to improve the driving teeth motion. The overall dimensions of the prototype stator are 30 mm (width × 30 mm (width × 50 mm (length. Driven by alternating current signals with the driving frequency of 50.93 kHz and voltage 300 VP-P, the motor gave a maximal no-load speed of 157.9 r/min and a maximal output torque of 11.76 mN m.

  16. Resonant gravimetric immunosensing based on capacitive micromachined ultrasound transducers

    KAUST Repository

    Viržonis, Darius

    2014-04-08

    High-frequency (40 MHz) and low-frequency (7 MHz) capacitive micromachined ultrasound transducers (CMUT) were fabricated and tested for use in gravimetric detection of biomolecules. The low-frequency CMUT sensors have a gold-coated surface, while the high-frequency sensors have a silicon nitride surface. Both surfaces were functionalized with bovine leukemia virus antigen gp51 acting as the antigen. On addition of an a specific antibody labeled with horseradish peroxidase (HRP), the antigen/antibody complex is formed on the surface and quantified by HRP-catalyzed oxidation of tetramethylbenzidine. It has been found that a considerably smaller quantity of immuno complex is formed on the high frequency sensor surface. In parallel, the loading of the surface of the CMUT was determined via resonance frequency and electromechanical resistance readings. Following the formation of the immuno complexes, the resonance frequencies of the low-frequency and high-frequency sensors decrease by up to 420 and 440 kHz, respectively. Finite element analysis reveals that the loading of the (gold-coated) low frequency sensors is several times larger than that on high frequency sensors. The formation of the protein film with pronounced elasticity and stress on the gold surface case is discussed. We also discuss the adoption of this method for the detection of DNA using a hybridization assay following polymerase chain reaction.

  17. 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.

  18. 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.

  19. Study on electrical impedance matching for broadband ultrasonic transducer

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Geon Woo [University of Science and Technology, Daejeon (Korea, Republic of); Kim, Ki Bok [Korea Research Institute of Standards and Science, Center for Safety Measurement, Daejeon (Korea, Republic of); Baek, Kwang Sae [Elache Co., Busan (Korea, Republic of)

    2017-02-15

    Ultrasonic transducers with high resolution and resonant frequency are required to detect small defects (less than hundreds of μm) by ultrasonic testing. The resonance frequency and resolution of an ultrasonic transducer are closely related to the thickness of piezo-electric materials, backing materials, and the electric impedance matching technique. Among these factors, electrical impedance matching plays an important role because it can reduce the loss and reflection of ultrasonic energy differences in electrical impedance between an ultrasonic transducer and an ultrasonic defects detecting system. An LC matching circuit is the most frequently used electric matching method. It is necessary for the electrical impedance of an ultrasonic transducer to correspond to approximately 50 Ω to compensate the difference in electrical impedance between both connections. In this study, a 15 MHz immersion ultrasonic transducer was fabricated and an LC electrical impedance circuit was applied to that for having broad-band frequency characteristic.

  20. Design of dual-band reflectarray using genetic algorithm

    Science.gov (United States)

    Maruyama, Tamami

    2017-07-01

    This paper proposes novel design method of dual-band reflectarray using genetic algorithm (GA). Ordinary, each elements of reflectarray are designed to have desired reflection phase. However, when we adopt same polarization in dual frequencies, the element configuration designed to satisfy desired reflection phase in one frequency influences the characteristics in other frequency. Therefore, it is difficult to achieve dual-band reflectarray. To address the issues, we adopt two layer patches for element to increase flexibility of design and optimize the patches configuration using GA. As a result, we achieve novel reflectarray that reflect wave towards the direction of theta equal to 27 deg. and phi equal to 0 deg. in dual frequency simultaneously when incidence wave is coming from the direction of theta equal to 0 deg. and phi equal to 0 deg. in dual frequency.

  1. 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

  2. The association between content of the elements S, Cl, K, Fe, Cu, Zn and Br in normal and cirrhotic liver tissue from Danes and Greenlandic Inuit examined by dual hierarchical clustering analysis

    DEFF Research Database (Denmark)

    Laursen, Jens; Milman, Nils; Pind, N.;

    2014-01-01

    contents according to calculated similarities, one clustering elements according to correlation coefficients between the element contents, both using Euclidian distance and Ward Procedure. RESULTS: One dendrogram separated subjects in 7 clusters showing no differences in ethnicity, gender or age....... The analysis discriminated between elements in normal and cirrhotic livers. The other dendrogram clustered elements in four clusters: sulphur and chlorine; copper and bromine; potassium and zinc; iron. There were significant correlations between the elements in normal liver samples: S was associated with Cl, K...

  3. Polarization diverse antenna for dual-band WLAN applications

    CSIR Research Space (South Africa)

    Steyn, JM

    2009-10-01

    Full Text Available A dual-band dual-polarized (DBDP) configuration is proposed for wireless local area network (WLAN) applications. A four-element array is used to facilitate operation in both the standard WLAN frequency bands (IEEE 802.11b and IEEE 802.11a...

  4. 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.

  5. Studying and Modeling Vibration Transducers and Accelerometers

    Directory of Open Access Journals (Sweden)

    Katalin Ágoston

    2010-12-01

    Full Text Available This paper presents types and operating mode of vibration sensors. Piezoelectric sensing elements are often used in accelerometers. It will be investigate the structure and transfer function of the seismic mass type sensing element. The article presents how the piezoelectric sensing element works and how can be modeled with an electronic circuit. The transfer functions of the electronic circuit models are studied in Matlab and the results are presented. It will be presented the influence of the seismic mass on the accelerometer’s working frequency domain.

  6. Hybrid organic–inorganic porous semiconductor transducer for multi-parameters sensing

    Science.gov (United States)

    Caliò, Alessandro; Cassinese, Antonio; Casalino, Maurizio; Rea, Ilaria; Barra, Mario; Chiarella, Fabio; De Stefano, Luca

    2015-01-01

    Porous silicon (PSi) non-symmetric multi-layers are modified by organic molecular beam deposition of an organic semiconductor, namely the N,N′-1H,1H-perfluorobutyldicyanoperylene-carboxydi-imide (PDIF-CN2). Joule evaporation of PDIF-CN2 into the PSi sponge-like matrix not only improves but also adds transducing skills, making this solid-state device a dual signal sensor for chemical monitoring. PDIF-CN2 modified PSi optical microcavities show an increase of about five orders of magnitude in electric current with respect to the same bare device. This feature can be used to sense volatile substances. PDIF-CN2 also improves chemical resistance of PSi against alkaline and acid corrosion. PMID:26063814

  7. 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.

  8. Theory and operation of 2-D array piezoelectric micromachined ultrasound transducers.

    Science.gov (United States)

    Dausch, David E; Castellucci, John B; Chou, Derrick R; von Ramm, Olaf T

    2008-11-01

    Piezoelectric micromachined ultrasound transducers (pMUTs) are a new approach for the construction of 2-D arrays for forward-looking 3-D intravascular (IVUS) and intracardiac (ICE) imaging. Two-dimensional pMUT test arrays containing 25 elements (5 x 5 arrays) were bulk micromachined in silicon substrates. The devices consisted of lead zirconate titanate (PZT) thin film membranes formed by deep reactive ion etching of the silicon substrate. Element widths ranged from 50 to 200 microm with pitch from 100 to 300 mum. Acoustic transmit properties were measured in de-ionized water with a calibrated hydrophone placed at a range of 20 mm. Measured transmit frequencies for the pMUT elements ranged from 4 to 13 MHz, and mode of vibration differed for the various element sizes. Element capacitance varied from 30 to over 400 pF depending on element size and PZT thickness. Smaller element sizes generally produced higher acoustic transmit output as well as higher frequency than larger elements. Thicker PZT layers also produced higher transmit output per unit electric field applied. Due to flexure mode operation above the PZT coercive voltage, transmit output increased nonlinearly with increased drive voltage. The pMUT arrays were attached directly to the Duke University T5 Phased Array Scanner to produce real-time pulse-echo B-mode images with the 2-D pMUT arrays.

  9. A bioanalytical microsystem for protein and DNA sensing based on a monolithic silicon optoelectronic transducer

    Energy Technology Data Exchange (ETDEWEB)

    Misiakos, K [Microelectronics Institute, NCSR ' Demokritos' , 15310, Athens (Greece); Petrou, P S [Immunoassay Lab., I/R-RP, NCSR ' Demokritos' , 15310, Athens (Greece); Kakabakos, S E [Immunoassay Lab., I/R-RP, NCSR ' Demokritos' , 15310, Athens (Greece); Ruf, H H [Fraunhofer Institute of Biomedical Engineering (IBMT) and University of Saarland, 66386, St Ingbert (Germany); Ehrentreich-Foerster, E [Department of Molecular Bioanalytics and Bioelectronics, Fraunhofer Institute for Biomedical Engineering, D-14558 Nuthetal (Germany); Bier, F F [Department of Molecular Bioanalytics and Bioelectronics, Fraunhofer Institute for Biomedical Engineering, D-14558 Nuthetal (Germany)

    2005-01-01

    A bioanalytical microsystem that is based on a monolithic silicon optical transducer and a microfluidic module and it is appropriate for real-time sensing of either DNA or protein analytes is presented. The optical transducer monolithically integrates silicon avalanche diodes as light sources, silicon nitride optical fibers and detectors and efficiently intercouples these optical elements through a self-alignment technique. After hydrophilization and silanization of the transducer surface, the biomolecular probes are immobilized through physical adsorption. Detection is performed through reaction of the immobilized biomolecules with gold nanoparticle labeled counterpart molecules. The binding of these molecules within the evanescent field at the surface of the optical fiber cause attenuated total reflection of the waveguided modes and reduction of the detector photocurrent. Using the developed microsystem, determination of single nucleotide polymorphism (SNP) in the gene of the human phenol sulfotransferase SULT1A1 was achieved. Full-matching hybrid resulted in 4-5 times higher signals compared to the mismatched hybrid after hybridization and dissociation processes. The protein sensing abilities of the developed microsystem were also investigated through a non-competitive assay for the determination of the MB isoform of creatine kinase enzyme (CK-MB) that is a widely used cardiac marker.

  10. A cylindrical traveling wave ultrasonic motor using a circumferential composite transducer.

    Science.gov (United States)

    Liu, Yingxiang; Liu, Junkao; Chen, Weishan

    2011-11-01

    This paper intends to present and verify a new idea for constructing traveling wave ultrasonic motors that may effectively avoid the drawbacks of conventional traveling wave motors using bonded PZT plates as the exciting elements. In the configuration of the motor's stator, a composite sandwich type transducer is used to excite a traveling wave in a cylinder with two cantilevers as the coupling bridges between the transducer and the cylinder. The design process of the stator is described using the FEM modal analysis method, and the establishment of traveling wave on the cylindrical stator was simulated by FEM transient analysis. To verify the theoretical analysis results, a laser Doppler scanner was employed to test the mode shapes of a prototype stator excited by the longitudinal and bending vibrations respectively. Finally, to validate the design idea, a prototype motor was fabricated and tested; the typical output features are no-load speed of 156 rpm and maximum torque of 0.75 N·m under exciting voltages of 70 V(rms) applied to excite the longitudinal vibration of the transducer and 200 V(rms) applied to excite the bending vibration.

  11. Implementing guided wave mode control by use of a phased transducer array.

    Science.gov (United States)

    Li, J; Rose, J L

    2001-05-01

    A multi-channel time-delay system has been built and applied to a transducer array for implementing guided wave mode control. The time-delay system has a capability of sending high energy controllable tone-burst signals from eight independent channels with arbitrary time delays from 0 to 30 microseconds with resolution of 0.025 microsecond. Software time delays are also provided for summing up received signals of each channel. Theoretical discussions indicate the impact of the time delay capability on the bandwidth and sensitivity improvement of a transducer array for guided wave generation. Determination of both physical and software time delay values is based on a knowledge of dispersion curves and element spacing. Based on reference signals, a non-knowledge-based automatic time-delay searching algorithm was introduced for guided wave mode selection. Experiments were conducted with a phased comb transducer array mounted on a carbon steel pipe. The experimental results show that signal to noise ratio has been greatly improved by use of the time-delay system. Some other benefits of the phased array, including unidirection generation and mode control flexibility, are discussed.

  12. Research on a Linear Piezoelectric Actuator Using T-Shape Transducer to Realize High Mechanical Output

    Directory of Open Access Journals (Sweden)

    Sijia Shao

    2016-04-01

    Full Text Available A modified large thrust ultrasonic linear motor using a T-shape configuration composed of two orthogonal sandwich-type transducers has been proposed in this paper. It is an improved version of a previous T-shape motor. The vertical transducer is used to generate the normal force between the driving foot and slider, while the other push-pull–type horizontal transducer is applied to generate driving force to push the working platform. By superimposing the two longitudinal vibrations, the proposed motor generates an elliptical movement on the driving foot. In order to improve the vibration characteristics and amplify the driving vibration amplitude, the shape of the driving foot and horn have been redesigned and optimized. The finite element method (FEM is used to adjust the structural parameters to degenerate the two working mode frequencies. The prototype has been fabricated and its mechanical output ability has been measured. The output characteristics of the modified motor, compared with the previous T-shape motor, achieve a relatively high level. The typical no-load speed and maximum output thrust of the prototype are 0.83 m/s and 56 N under an exciting voltage of 150 Vrms.

  13. Low-frequency ultrasonic Bessel-like collimated beam generation from radial modes of piezoelectric transducers

    Science.gov (United States)

    Chillara, Vamshi Krishna; Pantea, Cristian; Sinha, Dipen N.

    2017-02-01

    We present a very simple approach to generate a collimated ultrasonic beam that exploits the natural Bessel-like vibration pattern of the radial modes of a piezoelectric disc with lateral clamping. This eliminates the need for the conventional annular Bessel pattern of the electrodes with individual electrode excitation on the piezo-disc, thus simplifying the transducer design. Numerical and experimental studies are carried out to investigate the Bessel-like vibration patterns of these radial modes showing an excellent agreement between these two studies. Measured ultrasonic beam-profiles in water from the radial modes confirm the profile to be a Bessel beam. Collimated beam generation from radial modes is investigated using a coupled electromechanical finite-element model. It is found that clamping the lateral edges of piezoelectric transducers results in a high-degree of collimation with practically no side-lobes similar to a parametric array beam. Ultrasonic beam-profile measurements in water with both free and clamped piezoelectric transducer are presented. The collimated beam generation using the present technique of using the laterally clamped radial modes finds significant applications in low-frequency imaging through highly attenuating materials.

  14. 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

  15. 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.

  16. A Prototype PZT Matrix Transducer With Low-Power Integrated Receive ASIC for 3-D Transesophageal Echocardiography.

    Science.gov (United States)

    Chen, Chao; Raghunathan, Shreyas B; Yu, Zili; Shabanimotlagh, Maysam; Chen, Zhao; Chang, Zu-yao; Blaak, Sandra; Prins, Christian; Ponte, Jacco; Noothout, Emile; Vos, Hendrik J; Bosch, Johan G; Verweij, Martin D; de Jong, Nico; Pertijs, Michiel A P

    2016-01-01

    This paper presents the design, fabrication, and experimental evaluation of a prototype lead zirconium titanate (PZT) matrix transducer with an integrated receive ASIC, as a proof of concept for a miniature three-dimensional (3-D) transesophageal echocardiography (TEE) probe. It consists of an array of 9 ×12 piezoelectric elements mounted on the ASIC via an integration scheme that involves direct electrical connections between a bond-pad array on the ASIC and the transducer elements. The ASIC addresses the critical challenge of reducing cable count, and includes front-end amplifiers with adjustable gains and micro-beamformer circuits that locally process and combine echo signals received by the elements of each 3 ×3 subarray. Thus, an order-of-magnitude reduction in the number of receive channels is achieved. Dedicated circuit techniques are employed to meet the strict space and power constraints of TEE probes. The ASIC has been fabricated in a standard 0.18-μm CMOS process and consumes only 0.44 mW/channel. The prototype has been acoustically characterized in a water tank. The ASIC allows the array to be presteered across ±37° while achieving an overall dynamic range of 77 dB. Both the measured characteristics of the individual transducer elements and the performance of the ASIC are in good agreement with expectations, demonstrating the effectiveness of the proposed techniques.

  17. Multi-frequency harmonic arrays: initial experience with a novel transducer concept for nonlinear contrast imaging.

    Science.gov (United States)

    Forsberg, Flemming; Shi, William T; Jadidian, Bahram; Winder, Alan A

    2004-12-01

    Nonlinear contrast imaging modes such as second harmonic imaging (HI) and subharmonic imaging (SHI) are increasingly important for clinical applications. However, the performance of currently available transducers for HI and SHI is significantly constrained by their limited bandwidth. To bypass this constraint, a novel transducer concept termed multi-frequency harmonic transducer arrays (MFHA's) has been designed and a preliminary evaluation has been conducted. The MFHA may ultimately be used for broadband contrast enhanced HI and SHI with high dynamic range and consists of three multi-element piezo-composite sub-arrays (A-C) constructed so the center frequencies are 4f(A) = 2f(B) = f(C) (specifically 2.5/5.0/10.0 MHz and 1.75/3.5/7.0 MHz). In principle this enables SHI by transmitting on sub-array C receiving on B and, similarly, from B to A as well as HI by transmitting on A receiving on B and, likewise, from B to C. Initially transmit and receive pressure levels of the arrays were measured with the elements of each sub-array wired in parallel. Following contrast administration, preliminary in vitro HI and SHI signal-to-noise ratios of up to 40 dB were obtained. In conclusion, initial design and in vitro characterization of two MFHA's have been performed. They have an overall broad frequency bandwidth of at least two octaves. Due to the special design of the array assembly, the SNR for HI and SHI was comparable to that of regular B-mode and better than commercially available HI systems. However, further research on multi-element MFHA's is required before their potential for in vivo nonlinear contrast imaging can be assessed.

  18. Decentralized vibration control of a multi-link flexible robotic manipulator using smart piezoelectric transducers

    Science.gov (United States)

    Halim, Dunant; Luo, Xi; Trivailo, Pavel M.

    2014-11-01

    The work in this paper is aimed to investigate the use of a decentralized control system for suppressing vibration of a multi-link flexible robotic manipulator using embedded smart piezoelectric transducers. To achieve this, a non-linear dynamic model of a flexible robotic manipulator with smart piezoelectric actuators/sensors, is developed based on the co-rotational finite element method. The method incorporates multiple co-ordinate (co-rotational) systems which rotate and translate with each element, so that the geometric non-linearity present in rotating manipulator system can be dealt with efficiently. The placement of piezoelectric actuators and sensors over the flexible links are considered for the application of decentralized control system. A numerical study shows that the developed co-rotational finite element method can be utilized to investigate the piezoelectric actuator/sensor placement and vibration control performances for a multi-link flexible manipulator undertaking complicated motion.

  19. 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.

  20. 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.