Science.gov

Sample records for ultrasonic pulse transmission

  1. Cepstral method for the measurement of ultrasonic pulse transmission time variations

    NASA Astrophysics Data System (ADS)

    Gericke, Otto R.

    1989-04-01

    A precise method for determining relative changes or small differences in ultra-sonic pulse transmission times has been developed. The method uses multiple-echo signals obtained by injecting a pulsed, plane ultrasonic wave of the compressional mode into a sample with free, parallel surfaces. The ultrasonic transducer employed for this purpose acts as both transmitter and receiver. The received ultrasonic signals are subjected to two consecutive Fourier transformations to produce a cepstrum. The cepstral function derived from the multiple-echo signal exhibits characteristic maxima whose positions on the frequency abscissa, after calibration in units of time, represent multiples of the ultrasonic transmission time. Since minute variations of this time can be determined from a shift in the position of a cepstral maximum, the detection of very small changes or differences in sample thickness or ultrasonic propagation velocity becomes feasible.

  2. Experiments in Pulsed Ultrasonics

    ERIC Educational Resources Information Center

    Palmer, S. B.; Forster, G. A.

    1970-01-01

    Describes and apparatus designed to generate and detect pulsed ultrasonics in solids and liquids over the frequency range 1-20 MHz. Experiments are suggested for velocity of sound, elastic constant and ultrasonic attenuation measurements on various materials over a wide temperature range. The equipment should be useful for demonstration purposes.…

  3. Pulsed ultrasonic stir welding system

    NASA Technical Reports Server (NTRS)

    Ding, R. Jeffrey (Inventor)

    2013-01-01

    An ultrasonic stir welding system includes a welding head assembly having a plate and a rod passing through the plate. The rod is rotatable about a longitudinal axis thereof. During a welding operation, ultrasonic pulses are applied to the rod as it rotates about its longitudinal axis. The ultrasonic pulses are applied in such a way that they propagate parallel to the longitudinal axis of the rod.

  4. Pulsed ultrasonic stir welding method

    NASA Technical Reports Server (NTRS)

    Ding, R. Jeffrey (Inventor)

    2013-01-01

    A method of performing ultrasonic stir welding uses a welding head assembly to include a plate and a rod passing through the plate. The rod is rotatable about a longitudinal axis thereof. In the method, the rod is rotated about its longitudinal axis during a welding operation. During the welding operation, a series of on-off ultrasonic pulses are applied to the rod such that they propagate parallel to the rod's longitudinal axis. At least a pulse rate associated with the on-off ultrasonic pulses is controlled.

  5. Ultrasonic thermometry using pulse techniques.

    NASA Technical Reports Server (NTRS)

    Lynnworth, L. C.; Carnevale, E. H.

    1972-01-01

    Ultrasonic pulse techniques have been developed which, when applied to inert gases, provide temperature measurements up to 8000 K. The response time can be less than 1 msec. This is a significant feature in studying shock-heated or combusting gases. Using a momentary contact coupling technique, temperature has been measured inside steel from 300 to 1500 K. Thin-wire sensors have been used above 2000 K in nuclear and industrial applications where conditions preclude the use of thermocouples, resistance devices, or optical pyrometers. At 2500 K, temperature sensitivity of 0.1% is obtained in Re wire sensors 5 cm long by timing five round trips with an electronic instrument that resolves the time interval between selected echoes to 0.1 microsec. Sensors have been operated at rotational speeds over 2000 rpm and in noisy environments. Temperature profiling of up to ten regions using only a single guided path or beam has also been accomplished.

  6. Ultrasonic flowmetering with reflected pulses

    NASA Astrophysics Data System (ADS)

    Hoyle, D. C.; Glicksman, L. R.; Peterson, C. R.

    1984-09-01

    Consolidated Edison of New York City has expressed the need for a new gasmeter for accurately monitoring large diameter interdistrict gas transmission lines for loss due to theft or leakage. A research effort aimed at developing a new flowmeter for Con Edison is described. The new flowmeter uses ultrasonic flowmetering technology in a novel way to meet Con Edison's four major design specifications: the flowmeter should be accurate to 0.5 percent of totalized flow over one year, it should be much simpler to install than a conventional flowmeter, essentially meaning that excavation be limited to that necessary to expose the upper surface of a buried main; its installation must not require service shutdown; and, the flowmeter should not require zero-flow calibration once installed in the gas main.

  7. A Pulse Generator Based on an Arduino Platform for Ultrasonic Applications

    NASA Astrophysics Data System (ADS)

    Acevedo, Pedro; Vázquez, Mónica; Durán, Joel; Petrearce, Rodolfo

    The objective of this work is to use the Arduino platform as an ultrasonic pulse generator to excite PVDF ultrasonic arrays in transmission. An experimental setup was implemented using a through-transmission configuration to evaluate the performance of the generator.

  8. Pulse shaping with transmission lines

    DOEpatents

    Wilcox, R.B.

    1985-08-15

    A method and apparatus for forming shaped voltage pulses uses passive reflection from a transmission line with nonuniform impedance. The impedance of the reflecting line varies with length in accordance with the desired pulse shape. A high voltage input pulse is transmitted to the reflecting line. A reflected pulse is produced having the desired shape and is transmitted by pulse removal means to a load. Light activated photoconductive switches made of silicon can be utilized. The pulse shaper can be used to drive a Pockels cell to produce shaped optical pulses.

  9. Pulse shaping with transmission lines

    DOEpatents

    Wilcox, Russell B.

    1987-01-01

    A method and apparatus for forming shaped voltage pulses uses passive reflection from a transmission line with nonuniform impedance. The impedance of the reflecting line varies with length in accordance with the desired pulse shape. A high voltage input pulse is transmitted to the reflecting line. A reflected pulse is produced having the desired shape and is transmitted by pulse removal means to a load. Light activated photoconductive switches made of silicon can be utilized. The pulse shaper can be used to drive a Pockels cell to produce shaped optical pulses.

  10. Ultrasonic unipolar pulse/echo instrument

    DOEpatents

    Hughes, M.J.; Hsu, D.K.; Thompson, D.O.; Wormley, S.J.

    1993-04-06

    An ultrasonic unipolar pulse/echo instrument uses active switches and a timing and drive circuitry to control electrical energy to a transducer, the discharging of the transducer, and the opening of an electrical pathway to the receiving circuitry for the returning echoes. The active switches utilize MOSFET devices along with decoupling circuitry to insure the preservation of the unipolar nature of the pulses, insure fast transition times, and maintain broad band width and time resolution. A housing contains the various circuitry and switches and allows connection to a power supply and a movable ultrasonic transducer. The circuitry maintains low impedance input to the transducer during transmitting cycles, and high impedance between the transducer and the receiving circuit during receive cycles to maintain the unipolar pulse shape. A unipolar pulse is valuable for nondestructive evaluation, a prime use for the present instrument.

  11. Ultrasonic unipolar pulse/echo instrument

    DOEpatents

    Hughes, Michael S.; Hsu, David K.; Thompson, Donald O.; Wormley, Samuel J.

    1993-01-01

    An ultrasonic unipolar pulse/echo instrument uses active switches and a timing and drive circuitry to control electrical energy to a transducer, the discharging of the transducer, and the opening of an electrical pathway to the receiving circuitry for the returning echoes. The active switches utilize MOSFET devices along with decoupling circuitry to insure the preservation of the unipolar nature of the pulses, insure fast transition times, and maintain broad band width and time resolution. A housing contains the various circuitry and switches and allows connection to a power supply and a movable ultrasonic transducer. The circuitry maintains low impedance input to the transducer during transmitting cycles, and high impedance between the transducer and the receiving circuit during receive cycles to maintain the unipolar pulse shape. A unipolar pulse is valuable for nondestructive evaluation, a prime use for the present instrument.

  12. Method and means of transmitting and receiving broad-band unipolar, ultrasonic pulses for ultrasonic inspection

    DOEpatents

    Thompson, D.O.; Hsu, D.K.

    1993-12-14

    The invention includes a means and method for transmitting and receiving broadband, unipolar, ultrasonic pulses for ultrasonic inspection. The method comprises generating a generally unipolar ultrasonic stress pulse from a low impedance voltage pulse transmitter along a low impedance electrical pathway to an ultrasonic transducer, and receiving the reflected echo of the pulse by the transducer, converting it to a voltage signal, and passing it through a high impedance electrical pathway to an output. The means utilizes electrical components according to the method. The means and method allow a single transducer to be used in a pulse/echo mode, and facilitates alternatingly transmitting and receiving the broadband, unipolar, ultrasonic pulses. 25 figures.

  13. Method and means of transmitting and receiving broad-band unipolar, ultrasonic pulses for ultrasonic inspection

    DOEpatents

    Thompson, Donald O.; Hsu, David K.

    1993-12-14

    The invention includes a means and method for transmitting and receiving broadband, unipolar, ultrasonic pulses for ultrasonic inspection. The method comprises generating a generally unipolar ultrasonic stress pulse from a low impedance voltage pulse transmitter along a low impedance electrical pathway to an ultrasonic transducer, and receiving the reflected echo of the pulse by the transducer, converting it to a voltage signal, and passing it through a high impedance electrical pathway to an output. The means utilizes electrical components according to the method. The means and method allow a single transducer to be used in a pulse/echo mode, and facilitates alternatingly transmitting and receiving the broadband, unipolar, ultrasonic pulses.

  14. Coiled transmission line pulse generators

    DOEpatents

    McDonald, Kenneth Fox

    2010-11-09

    Methods and apparatus are provided for fabricating and constructing solid dielectric "Coiled Transmission Line" pulse generators in radial or axial coiled geometries. The pour and cure fabrication process enables a wide variety of geometries and form factors. The volume between the conductors is filled with liquid blends of monomers, polymers, oligomers, and/or cross-linkers and dielectric powders; and then cured to form high field strength and high dielectric constant solid dielectric transmission lines that intrinsically produce ideal rectangular high voltage pulses when charged and switched into matched impedance loads. Voltage levels may be increased by Marx and/or Blumlein principles incorporating spark gap or, preferentially, solid state switches (such as optically triggered thyristors) which produce reliable, high repetition rate operation. Moreover, these Marxed pulse generators can be DC charged and do not require additional pulse forming circuitry, pulse forming lines, transformers, or an a high voltage spark gap output switch. The apparatus accommodates a wide range of voltages, impedances, pulse durations, pulse repetition rates, and duty cycles. The resulting mobile or flight platform friendly cylindrical geometric configuration is much more compact, light-weight, and robust than conventional linear geometries, or pulse generators constructed from conventional components. Installing additional circuitry may accommodate optional pulse shape improvements. The Coiled Transmission Lines can also be connected in parallel to decrease the impedance, or in series to increase the pulse length.

  15. Wireless power transmission using ultrasonic guided waves

    NASA Astrophysics Data System (ADS)

    Kural, A.; Pullin, R.; Featherston, C.; Paget, C.; Holford, K.

    2011-07-01

    The unavailability of suitable power supply at desired locations is currently an important obstacle in the development of distributed, wireless sensor networks for applications such as structural health monitoring of aircraft. Proposed solutions range from improved batteries to energy harvesting from vibration, temperature gradients and other sources. A novel approach is being investigated at Cardiff University School of Engineering in cooperation with Airbus. It aims to utilise ultrasonic guided Lamb waves to transmit energy through the aircraft skin. A vibration generator is to be placed in a location where electricity supply is readily available. Ultrasonic waves generated by this device will travel through the aircraft structure to a receiver in a remote wireless sensor node. The receiver will convert the mechanical vibration of the ultrasonic waves back to electricity, which will be used to power the sensor node. This paper describes the measurement and modelling of the interference pattern which emerges when Lamb waves are transmitted continuously as in this power transmission application. The discovered features of the pattern, such as a large signal amplitude variation and a relatively high frequency, are presented and their importance for the development of a power transmission system is discussed.

  16. Medical tomograph system using ultrasonic transmission

    NASA Technical Reports Server (NTRS)

    Heyser, Richard C. (Inventor); Nathan, Robert (Inventor)

    1978-01-01

    Ultrasonic energy transmission in rectilinear array scanning patterns of soft tissue provides projection density values of the tissue which are recorded as a function of scanning position and angular relationship, .theta., of the subject with a fixed coordinate system. A plurality of rectilinear scan arrays in the same plane for different angular relationships .theta..sub.1 . . . .theta..sub.n thus recorded are superimposed. The superimposition of intensity values thus yields a tomographic image of an internal section of the tissue in the scanning plane.

  17. 21 CFR 892.1550 - Ultrasonic pulsed doppler imaging system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ultrasonic pulsed doppler imaging system. 892.1550 Section 892.1550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1550 Ultrasonic pulsed doppler...

  18. 21 CFR 892.1560 - Ultrasonic pulsed echo imaging system.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ultrasonic pulsed echo imaging system. 892.1560 Section 892.1560 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES RADIOLOGY DEVICES Diagnostic Devices § 892.1560 Ultrasonic pulsed echo...

  19. A Study on Propagation of Monopole Ultrasonic Pulse by Simulation and Experiment

    NASA Astrophysics Data System (ADS)

    Sato, Takeki; Inoue, Hiroshi; Murata, Kenji

    2006-05-01

    The shock wave or intense impulsive acoustic wave generated by an explosion, whether in air or in water, can produce unexpected lesions on the human body. Short monopole or impulsive-like ultrasonic pulses have a fast rise and are similar to a shock wave generated by an explosion. Investigation of the propagation of the monopole ultrasonic pulse in a lossy medium would be basic research for clarifing where the problems lie. In this study, we investigate the sound field of the monopole ultrasonic pulse in degassed water and glycerine by simulation and experiment, as well as its mechanism and effect in a lossy medium. The results show that waveform changed from a monopole to a dipole owing to a diffraction loss as the pulse transmitted in the medium, the amplitude of a received pulse was decreased considerably in glycerine by the large absorption, and also the rise of the amplitude was more gradual owing to the reduction of high-frequency components. A short monopole ultrasonic pulse will approach a shock wave if the wave propagates as a plane wave because the pulse remains impulsive. As a monopole ultrasonic pulse radiated from a small source is transmitted, a negative pressure grows, and its action on a medium per unit time will weaken owing to the large absorption of the transmission medium.

  20. Inline Ultrasonic Rheometry by Pulsed Doppler

    SciTech Connect

    Pfund, David M.; Greenwood, Margaret S.; Bamberger, Judith A.; Pappas, Richard A.

    2006-12-22

    This will be a discussion of the non-invasive determination of the viscosity of a non-Newtonian fluid in laminar pipe flow over the range of shear rates present in the pipe. The procedure used requires knowledge of the flow profile in and the pressure drop along a long straight run of pipe. The profile is determined by using a pulsed ultrasonic Doppler velocimeter. This approach is ideal for making non-invasive, real-time measurements for monitoring and control. Rheograms of a shear thinning, thixotropic gel will be presented. The operating parameters and limitations of the Doppler-based instrument will be discussed. The most significant limitation is velocity gradient broadening of the Doppler spectra near the walls of the pipe. This limitation can be significant for strongly shear thinning fluids (depending also on the ratio of beam to pipe diameter and the transducer's insertion angle).

  1. Prediction of concrete compression strength using ultrasonic pulse velocity

    NASA Astrophysics Data System (ADS)

    Azreen, M. N.; Pauzi, I. M.; Nasharuddin, I.; Haniza, M. M.; Akasyah, J.; Karsono, A. D.; Lei, V. Yen

    2016-01-01

    The relationship of ultrasonic stress waves transmitted along direct and indirect paths in concrete samples was investigated. Tests were conducted on plain concrete slabs from different grades of 15, 25, 30, 40 and Ultrahigh Performance Concrete that have dimensions of 750mm x 150mm x 150 mm. Direct ultrasonic pulse velocity tests were conducted between the top and the bottom surfaces of the concrete samples and indirect tests were conducted along the surface. A test procedure to determine indirect wave velocities was refined by defining the spacing of the transducers which are 50, 100, 150, 200, 250, 300, 350, 400, 450 mm. The correlation was established between direct and indirect UPV measurements via statistical analysis. From the analysis, it can be concluded that direct UPV has higher value than indirect UPV value by 16.5 % due to position of transducers. The compression strength of the concretes was studied to be compared with the direct and indirect transmission, with direct transmission method showed a good correlation with compression strength.

  2. Piston cylinder cell for high pressure ultrasonic pulse echo measurements

    NASA Astrophysics Data System (ADS)

    Kepa, M. W.; Ridley, C. J.; Kamenev, K. V.; Huxley, A. D.

    2016-08-01

    Ultrasonic techniques such as pulse echo, vibrating reed, or resonant ultrasound spectroscopy are powerful probes not only for studying elasticity but also for investigating electronic and magnetic properties. Here, we report on the design of a high pressure ultrasonic pulse echo apparatus, based on a piston cylinder cell, with a simplified electronic setup that operates with a single coaxial cable and requires sample lengths of mm only. The design allows simultaneous measurements of ultrasonic velocities and attenuation coefficients up to a pressure of 1.5 GPa. We illustrate the performance of the cell by probing the phase diagram of a single crystal of the ferromagnetic superconductor UGe2.

  3. Piston cylinder cell for high pressure ultrasonic pulse echo measurements.

    PubMed

    Kepa, M W; Ridley, C J; Kamenev, K V; Huxley, A D

    2016-08-01

    Ultrasonic techniques such as pulse echo, vibrating reed, or resonant ultrasound spectroscopy are powerful probes not only for studying elasticity but also for investigating electronic and magnetic properties. Here, we report on the design of a high pressure ultrasonic pulse echo apparatus, based on a piston cylinder cell, with a simplified electronic setup that operates with a single coaxial cable and requires sample lengths of mm only. The design allows simultaneous measurements of ultrasonic velocities and attenuation coefficients up to a pressure of 1.5 GPa. We illustrate the performance of the cell by probing the phase diagram of a single crystal of the ferromagnetic superconductor UGe2. PMID:27587156

  4. 21 CFR 892.1560 - Ultrasonic pulsed echo imaging system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Ultrasonic pulsed echo imaging system. 892.1560 Section 892.1560 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... pulsed sound beam into body tissue to determine the depth or location of the tissue interfaces and...

  5. 21 CFR 892.1560 - Ultrasonic pulsed echo imaging system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Ultrasonic pulsed echo imaging system. 892.1560 Section 892.1560 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... pulsed sound beam into body tissue to determine the depth or location of the tissue interfaces and...

  6. 21 CFR 892.1560 - Ultrasonic pulsed echo imaging system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Ultrasonic pulsed echo imaging system. 892.1560 Section 892.1560 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... pulsed sound beam into body tissue to determine the depth or location of the tissue interfaces and...

  7. 21 CFR 892.1560 - Ultrasonic pulsed echo imaging system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Ultrasonic pulsed echo imaging system. 892.1560 Section 892.1560 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... pulsed sound beam into body tissue to determine the depth or location of the tissue interfaces and...

  8. Using piezoelectric sensors for ultrasonic pulse velocity measurements in concrete

    NASA Astrophysics Data System (ADS)

    Kee, Seong-Hoon; Zhu, Jinying

    2013-11-01

    The ultrasonic pulse velocity (UPV) test has been a widely used non-destructive testing method for concrete structures. However, the conventional UPV test has limitations in consistency of results and applicability in hard-to-access regions of structures. The authors explore the feasibility of embedded piezoelectric (PZT) sensors for ultrasonic measurements in concrete structures. Two PZT sensors were embedded in a reinforced concrete specimen. One sensor worked as an actuator driven by an ultrasonic pulse-receiver, and another sensor worked as a receiver. A series of ultrasonic tests were conducted to investigate the performance of the embedded sensors in crack-free concrete and concrete specimens having a surface-breaking crack under various external loadings. Signals measured by the embedded sensors show a broad bandwidth with a centre frequency around 80 kHz, and very good coherence in the frequency range from 30 to 180 kHz. Furthermore, experimental variability in ultrasonic pulse velocity and attenuation is substantially reduced compared to previously reported values from conventional UPV equipment. Findings from this study demonstrate that the embedded sensors have great potential as a low-cost solution for ultrasonic transducers for health monitoring of concrete in structures.

  9. Correlation established between heat transfer and ultrasonic transmission properties of copper braze bonds

    NASA Technical Reports Server (NTRS)

    Dinovi, R. A.

    1967-01-01

    Measuring and correlating the thermal conductivity and ultrasonic transmission of seven hot-brazed-bonded copper plates established a relationship between heat transfer and ultrasonic transmission properties of the bonds. This relationship permits the prediction of heat transfer characteristics from ultrasonic transmission tests.

  10. Resonant ultrasonic wireless power transmission for bio-implants

    NASA Astrophysics Data System (ADS)

    Lee, Sung Q.; Youm, Woosub; Hwang, Gunn; Moon, Kee S.; Ozturk, Yusuf

    2014-03-01

    In this paper, we present the ultrasonic wireless power transmission system as part of a brain-machine interface (BMI) system in development to supply the required electric power. Making a small-size implantable BMI, it is essential to design a low power unit with a rechargeable battery. The ultrasonic power transmission system has two piezoelectric transducers, facing each other between skin tissues converting electrical energy to mechanical vibrational energy or vice versa. Ultrasound is free from the electromagnetic coupling effect and medical frequency band limitations which making it a promising candidate for implantable purposes. In this paper, we present the design of piezoelectric composite transducer, the rectifier circuit, and rechargeable battery that all packaged in biocompatible titanium can. An initial prototype device was built for demonstration purpose. The early experimental results demonstrate the prototype device can reach 50% of energy transmission efficiency in a water medium at 20mm distance and 18% in animal skin tissue at 18mm distance, respectively.

  11. 21 CFR 892.1550 - Ultrasonic pulsed doppler imaging system.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Ultrasonic pulsed doppler imaging system. 892.1550 Section 892.1550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... determine stationary body tissue characteristics, such as depth or location of tissue interfaces or...

  12. 21 CFR 892.1550 - Ultrasonic pulsed doppler imaging system.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Ultrasonic pulsed doppler imaging system. 892.1550 Section 892.1550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... determine stationary body tissue characteristics, such as depth or location of tissue interfaces or...

  13. 21 CFR 892.1550 - Ultrasonic pulsed doppler imaging system.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Ultrasonic pulsed doppler imaging system. 892.1550 Section 892.1550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... determine stationary body tissue characteristics, such as depth or location of tissue interfaces or...

  14. 21 CFR 892.1550 - Ultrasonic pulsed doppler imaging system.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Ultrasonic pulsed doppler imaging system. 892.1550 Section 892.1550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES... determine stationary body tissue characteristics, such as depth or location of tissue interfaces or...

  15. Effect of laser pulse duration in picosecond ultrasonics

    NASA Astrophysics Data System (ADS)

    Dehoux, T.; Perton, M.; Chigarev, N.; Rossignol, C.; Rampnoux, J.-M.; Audoin, B.

    2006-09-01

    An optical grating has been introduced in a picosecond ultrasonics experiment, in order to vary continuously the duration of the laser beam pulse from 0.1to150ps. The evolution of the measured signal has been observed and analyzed through the comparison with a theoretical approach based on a two-temperature model. The latter allows matching the acoustic echoes together with the thermal background and the coincidence peak, for each pulse duration and at any time scale. The broadening of the acoustic echoes and the disappearing of its Brillouin component, along with the diminishing of the thermal coincidence peak, have been demonstrated when increasing the pulse duration. For a constant incident pulse energy, the efficiency of acoustic generation is optimum for the shortest pulses. Nevertheless, for longer pulses designed to obtain thermal conditions below the ablation threshold, acoustic generation could be enhanced.

  16. Evaluation of a pulsed ultrasonic Doppler flowmeter

    NASA Technical Reports Server (NTRS)

    Wells, M. K.

    1973-01-01

    The in vivo application of the pulsed ultrasound Doppler velocity meter (PUDVM) for measuring arterial velocity waveforms is reported. In particular, the performance of the PUDVM is compared with a hot film anemometer of proven accuracy.

  17. Measurement of ice accretion using ultrasonic pulse echo techniques

    NASA Technical Reports Server (NTRS)

    Hansman, R. John, Jr.; Kirby, Mark S.

    1987-01-01

    Many figures are given to illustrate the measurement of ice deposition using ultrasonic pulse echo techniques. The basic concept is to measure the thickness of the ice by relating the pulse echo time to the speed of sound. The measurements are made in an icing research tunnel (IRT), where echo patterns are videotaped during icing exposures under a variety of conditions. Typical echo patterns for different types of ice are illustrated. A table summarizing the icing rates measured in the IRT, along with the presence or absence of surface water is also given.

  18. Evaluation of correlation between physical properties and ultrasonic pulse velocity of fired clay samples.

    PubMed

    Özkan, İlker; Yayla, Zeliha

    2016-03-01

    The aim of this study is to establish a correlation between physical properties and ultrasonic pulse velocity of clay samples fired at elevated temperatures. Brick-making clay and pottery clay were studied for this purpose. The physical properties of clay samples were assessed after firing pressed clay samples separately at temperatures of 850, 900, 950, 1000, 1050 and 1100 °C. A commercial ultrasonic testing instrument (Proceq Pundit Lab) was used to evaluate the ultrasonic pulse velocity measurements for each fired clay sample as a function of temperature. It was observed that there became a relationship between physical properties and ultrasonic pulse velocities of the samples. The results showed that in consequence of increasing densification of the samples, the differences between the ultrasonic pulse velocities were higher with increasing temperature. These findings may facilitate the use of ultrasonic pulse velocity for the estimation of physical properties of fired clay samples. PMID:26725032

  19. Layered material characterization using ultrasonic transmission. An inverse estimation methodology.

    PubMed

    Messineo, María G; Rus, Guillermo; Eliçabe, Guillermo E; Frontini, Gloria L

    2016-02-01

    This paper presents an inverse methodology with the aim to characterize a layered material through the identification of acoustical and mechanical properties of its layers. The framework to accomplish this objective is provided by the Inverse Problems (IPs) theory. Material characterization refers to the detection and localization of discontinuities, as well as to the identification of physical properties, in order to predict the material behaviour. In this particular case, the IP is solved in the form of a parameter estimation problem, in which the goal is the estimation of the characteristic acoustic impedance, transit time, and attenuation of each layer. These parameters are directly related to relevant material properties, such as the speed of sound, density, elastic modulus and elastic energy dissipation constants. The IP solution is obtained by minimizing a cost functional formulated as the least squares error between the waveform calculated using an equivalent model, and the measured waveform obtained from ultrasonic transmission tests. The applied methodology allowed the accurate estimation of the desired parameters in materials composed of up to three layers. As a second contribution, a power law frequency dependence of the wave attenuation was identified for several homogeneous materials, based on the same ultrasonic transmission experiments. PMID:26456278

  20. Pulse transmission transceiver architecture for low power communications

    DOEpatents

    Dress, Jr., William B.; Smith, Stephen F.

    2003-08-05

    Systems and methods for pulse-transmission low-power communication modes are disclosed. A method of pulse transmission communications includes: generating a modulated pulse signal waveform; transforming said modulated pulse signal waveform into at least one higher-order derivative waveform; and transmitting said at least one higher-order derivative waveform as an emitted pulse. The systems and methods significantly reduce lower-frequency emissions from pulse transmission spread-spectrum communication modes, which reduces potentially harmful interference to existing radio frequency services and users and also simultaneously permit transmission of multiple data bits by utilizing specific pulse shapes.

  1. Monitoring of concrete structures using the ultrasonic pulse velocity method

    NASA Astrophysics Data System (ADS)

    Karaiskos, G.; Deraemaeker, A.; Aggelis, D. G.; Van Hemelrijck, D.

    2015-11-01

    Concrete is the material most produced by humanity. Its popularity is mainly based on its low production cost and great structural design flexibility. Its operational and ambient loadings including environmental effects have a great impact in the performance and overall cost of concrete structures. Thus, the quality control, the structural assessment, the maintenance and the reliable prolongation of the operational service life of the existing concrete structures have become a major issue. In the recent years, non-destructive testing (NDT) is becoming increasingly essential for reliable and affordable quality control and integrity assessment not only during the construction of new concrete structures, but also for the existing ones. Choosing the right inspection technique is always followed by a compromise between its performance and cost. In the present paper, the ultrasonic pulse velocity (UPV) method, which is the most well known and widely accepted ultrasonic concrete NDT method, is thoroughly reviewed and compared with other well-established NDT approaches. Their principles, inherent limitations and reliability are reviewed. In addition, while the majority of the current UPV techniques are based on the use of piezoelectric transducers held on the surface of the concrete, special attention is paid to a very promising technique using low-cost and aggregate-size piezoelectric transducers embedded in the material. That technique has been evaluated based on a series of parameters, such as the ease of use, cost, reliability and performance.

  2. Pulse transmission receiver with higher-order time derivative pulse correlator

    DOEpatents

    Dress, Jr., William B.; Smith, Stephen F.

    2003-09-16

    Systems and methods for pulse-transmission low-power communication modes are disclosed. A pulse transmission receiver includes: a higher-order time derivative pulse correlator; a demodulation decoder coupled to the higher-order time derivative pulse correlator; a clock coupled to the demodulation decoder; and a pseudorandom polynomial generator coupled to both the higher-order time derivative pulse correlator and the clock. The systems and methods significantly reduce lower-frequency emissions from pulse transmission spread-spectrum communication modes, which reduces potentially harmful interference to existing radio frequency services and users and also simultaneously permit transmission of multiple data bits by utilizing specific pulse shapes.

  3. Pulse transmission transmitter including a higher order time derivate filter

    DOEpatents

    Dress, Jr., William B.; Smith, Stephen F.

    2003-09-23

    Systems and methods for pulse-transmission low-power communication modes are disclosed. A pulse transmission transmitter includes: a clock; a pseudorandom polynomial generator coupled to the clock, the pseudorandom polynomial generator having a polynomial load input; an exclusive-OR gate coupled to the pseudorandom polynomial generator, the exclusive-OR gate having a serial data input; a programmable delay circuit coupled to both the clock and the exclusive-OR gate; a pulse generator coupled to the programmable delay circuit; and a higher order time derivative filter coupled to the pulse generator. The systems and methods significantly reduce lower-frequency emissions from pulse transmission spread-spectrum communication modes, which reduces potentially harmful interference to existing radio frequency services and users and also simultaneously permit transmission of multiple data bits by utilizing specific pulse shapes.

  4. Composite NDE using full-field pulse-echo ultrasonic propagation imaging system

    NASA Astrophysics Data System (ADS)

    Hong, Seung-Chan; Lee, Jung-Ryul; Park, Jongwoon

    2016-04-01

    In this paper, a novel ultrasonic propagation imaging system, called a full-field pulse-echo ultrasonic propagation imaging (FF PE UPI) system is presented. The coincided laser beams for ultrasonic sensing and generation are scanned and pulse-echo mode laser ultrasounds are captured. This procedure makes it possible to generate full-field ultrasound in through-the-thickness direction as large as the scan area. The system nondestructively inspected targets with two-axis translation stages. Various structural inspection results in the form of full-field ultrasonic wave propagation videos are introduced, which are an aluminum honeycomb sandwich, ailerons and carbon fiber reinforced plastic (CFRP) honeycomb sandwich structures including various defects.

  5. Detection of cystic structures using pulsed ultrasonically induced resonant cavitation

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph (Inventor); Kovach, John S. (Inventor)

    2002-01-01

    Apparatus and method for early detection of cystic structures indicative of ovarian and breast cancers uses ultrasonic wave energy at a unique resonance frequency for inducing cavitation in cystic fluid characteristic of cystic structures in the ovaries associated with ovarian cancer, and in cystic structures in the breast associated with breast cancer. Induced cavitation bubbles in the cystic fluid implode, creating implosion waves which are detected by ultrasonic receiving transducers attached to the abdomen of the patient. Triangulation of the ultrasonic receiving transducers enables the received signals to be processed and analyzed to identify the location and structure of the cyst.

  6. Fundamental Development of Ultrasonic Information Transmission System for Wearable Devices

    NASA Astrophysics Data System (ADS)

    Suzuki, Shin-nosuke; Ishihara, Manabu; Kobayashi, Yukio; Katane, Tamotsu; Saito, Osami; Kobayashi, Kazuto

    2009-07-01

    A wearable device is an electronic device miniaturized to a wearable size with computing and wireless communication functions. In this study, we have applied a communication system using ultrasonic waves to a wearable device. Ultrasonic waves are safe for the human body and do not cause the malfunction of electronic equipment. In addition, communication using ultrasonic waves is effective for preventing “skimming” because ultrasonic waves can transmit through the human body and have a large attenuation in air. Wearable devices can also be used in areas where electromagnetic waves are limited. We have developed an experimental prototype device. The prototype contains a one-chip microcomputer used to verify the size and battery consumption of the wearable device. As a result, the developed prototype realized bidirectional communication with a suitable device size and power consumption. The communication speed corresponds to 250 kbps. This value is equivalent to that of a conventional IC card system using electromagnetic waves. With this proposed system, we can achive various practical applications that can maintain absolute privacy while transmitting information through the human body.

  7. Method of estimating tissue attenuation using wideband ultrasonic pulse and apparatus for use therein

    SciTech Connect

    Flax, S.W.

    1986-11-11

    This patent describes a method of estimating tissue attenuation of ultrasound energy comprising the steps of: transmitting a wide band ultrasonic pulse into the tissue, the pulse having a frequency spectrum with a center frequency, detecting the pulse as reflected by the tissue, estimating decay of a measure of amplitude of the reflected pulse between two levels in the tissue to approximate the slope of the decay, estimating center frequency of the reflected pulse between the two levels, and obtaining tissue attenuation from the approximated slope of a measure of amplitude and the center frequency.

  8. Rotational swashplate pulse continuously variable transmission based on helical gear axial meshing transmission

    NASA Astrophysics Data System (ADS)

    Sun, Jiandong; Fu, Wenyu; Lei, Hong; Tian, E.; Liu, Ziping

    2012-11-01

    The current research on pulse continuously variable transmission(CVT) is mainly focused on reducing the pulse degree and making pulse degrees a constant value. Current research mainly confined to find out new design parameters by using the method of optimization, and reduce the pulse degree of pulse CVT and its range of variation. But the fact is that the reduction of the pulse degree is not significant. This article presents a new structure of mechanical pulse CVT—the rotational swashplate pulse CVT with driven by helical gear axial meshing. This transmission is simple and compact in structure and low in pulsatile rate (it adopts 6 guide rods), and the pulsatile degree is irrelevant to the transmission ratio. Theoretically, pulsatile rate could be reduced to zero if appropriate curved surface of the swashplate is used. Compared with the connecting rod pulse CVT, the present structure uses helical gear mechanism as transmission part and it avoids unbalanced inertial force in the former model. This paper analyzes the principle of driving of this transmission, presents its mechanical structure, and discusses its motion characteristics. Experimental prototype of this type of CVT has been manufactured. Tests for the transmission efficiency(when the rotational speed of the output shaft is the maximum) and the angular velocity of the output shaft have been carried out, and data have been analyzed. The experimental results show that the speed of the output shaft for the experimental prototype is slightly lower than the theoretical value, and the transmission efficiency of the experimental prototype is about 70%. The pulse degree of the CVT discussed in this paper is less than the existing pulse CVT of other types, and it is irrelevant to the transmission ratio of the CVT. The research provides the new idea to the CVT study.

  9. Prediction of ultrasonic pulse velocity for enhanced peat bricks using adaptive neuro-fuzzy methodology.

    PubMed

    Motamedi, Shervin; Roy, Chandrabhushan; Shamshirband, Shahaboddin; Hashim, Roslan; Petković, Dalibor; Song, Ki-Il

    2015-08-01

    Ultrasonic pulse velocity is affected by defects in material structure. This study applied soft computing techniques to predict the ultrasonic pulse velocity for various peats and cement content mixtures for several curing periods. First, this investigation constructed a process to simulate the ultrasonic pulse velocity with adaptive neuro-fuzzy inference system. Then, an ANFIS network with neurons was developed. The input and output layers consisted of four and one neurons, respectively. The four inputs were cement, peat, sand content (%) and curing period (days). The simulation results showed efficient performance of the proposed system. The ANFIS and experimental results were compared through the coefficient of determination and root-mean-square error. In conclusion, use of ANFIS network enhances prediction and generation of strength. The simulation results confirmed the effectiveness of the suggested strategies. PMID:25957464

  10. Gas ultrasonic flow rate measurement through genetic-ant colony optimization based on the ultrasonic pulse received signal model

    NASA Astrophysics Data System (ADS)

    Hou, Huirang; Zheng, Dandan; Nie, Laixiao

    2015-04-01

    For gas ultrasonic flowmeters, the signals received by ultrasonic sensors are susceptible to noise interference. If signals are mingled with noise, a large error in flow measurement can be caused by triggering mistakenly using the traditional double-threshold method. To solve this problem, genetic-ant colony optimization (GACO) based on the ultrasonic pulse received signal model is proposed. Furthermore, in consideration of the real-time performance of the flow measurement system, the improvement of processing only the first three cycles of the received signals rather than the whole signal is proposed. Simulation results show that the GACO algorithm has the best estimation accuracy and ant-noise ability compared with the genetic algorithm, ant colony optimization, double-threshold and enveloped zero-crossing. Local convergence doesn’t appear with the GACO algorithm until -10 dB. For the GACO algorithm, the converging accuracy and converging speed and the amount of computation are further improved when using the first three cycles (called GACO-3cycles). Experimental results involving actual received signals show that the accuracy of single-gas ultrasonic flow rate measurement can reach 0.5% with GACO-3 cycles, which is better than with the double-threshold method.

  11. Pulse transmission receiver with higher-order time derivative pulse generator

    DOEpatents

    Dress, Jr., William B.; Smith, Stephen F.

    2003-08-12

    Systems and methods for pulse-transmission low-power communication modes are disclosed. A pulse transmission receiver includes: a front-end amplification/processing circuit; a synchronization circuit coupled to the front-end amplification/processing circuit; a clock coupled to the synchronization circuit; a trigger signal generator coupled to the clock; and at least one higher-order time derivative pulse generator coupled to the trigger signal generator. The systems and methods significantly reduce lower-frequency emissions from pulse transmission spread-spectrum communication modes, which reduces potentially harmful interference to existing radio frequency services and users and also simultaneously permit transmission of multiple data bits by utilizing specific pulse shapes.

  12. Compressive strength evaluation of structural lightweight concrete by non-destructive ultrasonic pulse velocity method.

    PubMed

    Bogas, J Alexandre; Gomes, M Glória; Gomes, Augusto

    2013-07-01

    In this paper the compressive strength of a wide range of structural lightweight aggregate concrete mixes is evaluated by the non-destructive ultrasonic pulse velocity method. This study involves about 84 different compositions tested between 3 and 180 days for compressive strengths ranging from about 30 to 80 MPa. The influence of several factors on the relation between the ultrasonic pulse velocity and compressive strength is examined. These factors include the cement type and content, amount of water, type of admixture, initial wetting conditions, type and volume of aggregate and the partial replacement of normal weight coarse and fine aggregates by lightweight aggregates. It is found that lightweight and normal weight concretes are affected differently by mix design parameters. In addition, the prediction of the concrete's compressive strength by means of the non-destructive ultrasonic pulse velocity test is studied. Based on the dependence of the ultrasonic pulse velocity on the density and elasticity of concrete, a simplified expression is proposed to estimate the compressive strength, regardless the type of concrete and its composition. More than 200 results for different types of aggregates and concrete compositions were analyzed and high correlation coefficients were obtained. PMID:23351273

  13. Prediction of concrete strength using ultrasonic pulse velocity and artificial neural networks.

    PubMed

    Trtnik, Gregor; Kavcic, Franci; Turk, Goran

    2009-01-01

    Ultrasonic pulse velocity technique is one of the most popular non-destructive techniques used in the assessment of concrete properties. However, it is very difficult to accurately evaluate the concrete compressive strength with this method since the ultrasonic pulse velocity values are affected by a number of factors, which do not necessarily influence the concrete compressive strength in the same way or to the same extent. This paper deals with the analysis of such factors on the velocity-strength relationship. The relationship between ultrasonic pulse velocity, static and dynamic Young's modulus and shear modulus was also analyzed. The influence of aggregate, initial concrete temperature, type of cement, environmental temperature, and w/c ratio was determined by our own experiments. Based on the experimental results, a numerical model was established within the Matlab programming environment. The multi-layer feed-forward neural network was used for this purpose. The paper demonstrates that artificial neural networks can be successfully used in modelling the velocity-strength relationship. This model enables us to easily and reliably estimate the compressive strength of concrete by using only the ultrasonic pulse velocity value and some mix parameters of concrete. PMID:18589471

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

    NASA Technical Reports Server (NTRS)

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

    2016-01-01

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

  15. Laser-generated ultrasonic pulse shapes at solid wedges.

    PubMed

    Pupyrev, Pavel D; Lomonosov, Alexey M; Mayer, Andreas P

    2016-08-01

    Laser pulses focused near the tip of an elastic wedge generate acoustic waves guided at its apex. The shapes of the acoustic wedge wave pulses depend on the energy and the profile of the exciting laser pulse and on the anisotropy of the elastic medium the wedge is made of. Expressions for the acoustic pulse shapes have been derived in terms of the modal displacement fields of wedge waves for laser excitation in the thermo-elastic regime and for excitation via a pressure pulse exerted on the surface. The physical quantity considered is the local inclination of a surface of the wedge, which is measured optically by laser-probe-beam deflection. Experimental results on pulse shapes in the thermo-elastic regime are presented and confirmed by numerical calculations. They pertain to an isotropic sharp-angle wedge with two wedge-wave branches and to a non-reciprocity phenomenon at rectangular silicon edges. PMID:27135188

  16. Application of wavelet filtering and Barker-coded pulse compression hybrid method to air-coupled ultrasonic testing

    NASA Astrophysics Data System (ADS)

    Zhou, Zhenggan; Ma, Baoquan; Jiang, Jingtao; Yu, Guang; Liu, Kui; Zhang, Dongmei; Liu, Weiping

    2014-10-01

    Air-coupled ultrasonic testing (ACUT) technique has been viewed as a viable solution in defect detection of advanced composites used in aerospace and aviation industries. However, the giant mismatch of acoustic impedance in air-solid interface makes the transmission efficiency of ultrasound low, and leads to poor signal-to-noise (SNR) ratio of received signal. The utilisation of signal-processing techniques in non-destructive testing is highly appreciated. This paper presents a wavelet filtering and phase-coded pulse compression hybrid method to improve the SNR and output power of received signal. The wavelet transform is utilised to filter insignificant components from noisy ultrasonic signal, and pulse compression process is used to improve the power of correlated signal based on cross-correction algorithm. For the purpose of reasonable parameter selection, different families of wavelets (Daubechies, Symlet and Coiflet) and decomposition level in discrete wavelet transform are analysed, different Barker codes (5-13 bits) are also analysed to acquire higher main-to-side lobe ratio. The performance of the hybrid method was verified in a honeycomb composite sample. Experimental results demonstrated that the proposed method is very efficient in improving the SNR and signal strength. The applicability of the proposed method seems to be a very promising tool to evaluate the integrity of high ultrasound attenuation composite materials using the ACUT.

  17. Ultrasonic Pulse Waves Propagating through Cancellous Bone Phantoms with Aligned Pore Spaces

    NASA Astrophysics Data System (ADS)

    Hosokawa, Atsushi

    2006-05-01

    To elucidate the propagation phenomena of ultrasonic waves in cancellous bone related to trabecular structure, pulse waves propagating through three cancellous bone phantoms with different skeletal frames have been experimentally observed using a water-immersion ultrasonic technique. Skeletal frames with regularly aligned pore spaces were formed to imitate the orthotropic trabecular structure, using wire gauzes, punched plates and honeycomb ceramics. The propagations of the fast and slow waves, which were clearly observed in the direction of the trabecular alignment of cancellous bone, were investigated with the frame’s structures of these phantoms.

  18. Ultrasonic test system

    NASA Astrophysics Data System (ADS)

    Smith, Anthony; Goff, Dan; Kruchowy, Roman; Rhoads, Carl

    1994-08-01

    An ultrasonic system for determining the quality of concrete under water without inaccuracies caused by electromagnetic interference from the ultrasonic generator. An ultrasonic generator applies pulses to the concrete. An ultrasonic detector detects the ultrasonic pulses and produces corresponding signals that are indicative of ultrasonic pulses that have passed through the material. Signal processing circuitry processes the signals to determine the transit time of the ultrasonic pulses through the material. The signal processing circuitry is disabled for a predetermined time after application of each ultrasonic pulse to the material to prevent noise produced by the means for applying ultrasonic pulses to the material from entering the signal processing circuitry and causing spurious measurements.

  19. Method and apparatus for characterizing reflected ultrasonic pulses

    NASA Technical Reports Server (NTRS)

    Yost, William T. (Inventor); Cantrell, John H., Jr. (Inventor)

    1991-01-01

    The invention is a method of and apparatus for characterizing the amplitudes of a sequence of reflected pulses R1, R2, and R3 by converting them into corresponding electric signals E1, E2, and E3 to substantially the same value during each sequence thereby restoring the reflected pulses R1, R2, and R3 to their initial reflection values by timing means, an exponential generator, and a time gain compensator. Envelope and baseline reject circuits permit the display and accurate location of the time spaced sequence of electric signals having substantially the same amplitude on a measurement scale on a suitable video display or oscilloscope.

  20. Correlation between compressive strength and ultrasonic pulse velocity of high strength concrete incorporating chopped basalt fibre

    NASA Astrophysics Data System (ADS)

    Shafiq, Nasir; Fadhilnuruddin, Muhd; Elshekh, Ali Elheber Ahmed; Fathi, Ahmed

    2015-07-01

    Ultrasonic pulse velocity (UPV), is considered as the most important test for non-destructive techniques that are used to evaluate the mechanical characteristics of high strength concrete (HSC). The relationship between the compressive strength of HSC containing chopped basalt fibre stands (CBSF) and UPV was investigated. The concrete specimens were prepared using a different ratio of CBSF as internal strengthening materials. The compressive strength measurements were conducted at the sample ages of 3, 7, 28, 56 and 90 days; whilst, the ultrasonic pulse velocity was measured at 28 days. The result of HSC's compressive strength with the chopped basalt fibre did not show any improvement; instead, it was decreased. The UPV of the chopped basalt fibre reinforced concrete has been found to be less than that of the control mix for each addition ratio of the basalt fibre. A relationship plot is gained between the cube compressive strength for HSC and UPV with various amounts of chopped basalt fibres.

  1. Elastic moduli of precompressed pyrophyllite used in ultrahigh pressure research. [propagation of ultrasonic pulses

    NASA Technical Reports Server (NTRS)

    Sachse, W.; Ruoff, A. L.

    1974-01-01

    The propagation of ultrasonic pulses in pyrophyllite specimens was studied to determine the effect of specimen precompression on the measured elastic moduli. Measurements were made at room pressure and, for the precompressed specimens, to pressures of 3 kbar. Pyrophyllite was found to be elastically anisotropic, apparently the result of the fabric present in our material. The room pressure adiabatic bulk modulus as measured on specimens made of isostatically compacted powered pyrophyllite was determined to be 96.1 kbar. The wave speeds of ultrasonic pulses in pyrophyllite were found to decrease with increasing specimen precompression. A limiting value of precompression was found, above which no further decrease in wave speed was observed. For the shear wave speeds this occurs at 10 kbar while for the longitudinal wave at 25 kbar. In the limit, the shear waves propagate 20% slower than in the unprecompressed samples; for the longitudinal wave the difference is 30%.

  2. Pulsed Power for a Dynamic Transmission Electron Microscope

    SciTech Connect

    dehope, w j; browning, n; campbell, g; cook, e; king, w; lagrange, t; reed, b; stuart, b; Shuttlesworth, R; Pyke, B

    2009-06-25

    Lawrence Livermore National Laboratory (LLNL) has converted a commercial 200kV transmission electron microscope (TEM) into an ultrafast, nanoscale diagnostic tool for material science studies. The resulting Dynamic Transmission Electron Microscope (DTEM) has provided a unique tool for the study of material phase transitions, reaction front analyses, and other studies in the fields of chemistry, materials science, and biology. The TEM's thermionic electron emission source was replaced with a fast photocathode and a laser beam path was provided for ultraviolet surface illumination. The resulting photoelectron beam gives downstream images of 2 and 20 ns exposure times at 100 and 10 nm spatial resolution. A separate laser, used as a pump pulse, is used to heat, ignite, or shock samples while the photocathode electron pulses, carefully time-synchronized with the pump, function as probe in fast transient studies. The device functions in both imaging and diffraction modes. A laser upgrade is underway to make arbitrary cathode pulse trains of variable pulse width of 10-1000 ns. Along with a fast e-beam deflection scheme, a 'movie mode' capability will be added to this unique diagnostic tool. This talk will review conventional electron microscopy and its limitations, discuss the development and capabilities of DTEM, in particularly addressing the prime and pulsed power considerations in the design and fabrication of the DTEM, and conclude with the presentation of a deflector and solid-state pulser design for Movie-Mode DTEM.

  3. Plasma absorption evidence via chirped pulse spectral transmission measurements

    SciTech Connect

    Jedrkiewicz, Ottavia; Minardi, Stefano; Couairon, Arnaud; Jukna, Vytautas; Selva, Marco; Di Trapani, Paolo

    2015-06-08

    This work aims at highlighting the plasma generation dynamics and absorption when a Bessel beam propagates in glass. We developed a simple diagnostics allowing us to retrieve clear indications of the formation of the plasma in the material, thanks to transmission measurements in the angular and wavelength domains. This technique featured by the use of a single chirped pulse having the role of pump and probe simultaneously leads to results showing the plasma nonlinear absorption effect on the trailing part of the pulse, thanks to the spectral-temporal correspondence in the measured signal, which is also confirmed by numerical simulations.

  4. Prospects of pulse phase thermography for finding disbonds in CFRP-sandwich parts with aluminum honeycomb cores compared to ultrasonic

    NASA Astrophysics Data System (ADS)

    Gruber, J.; Stotter, B.; Mayr, G.; Hendorfer, G.

    2013-01-01

    This work shows the prospects of pulse phase thermography (PPT) compared to ultrasonic testing when applied to carbon fiber reinforced polymer (CFRP) sandwich parts with aluminum honeycomb cores. Measurements were carried out on full-scale components with flaws like disbonds, septum disbonds, staggers and displaced cores, where the last two are not literally flaws, but nevertheless regions of interest. The effect of the measurement time and the feasibility of extrapolating temperature decays were evaluated. Phase images, gathered with PPT, are compared with ultrasonic Cscan images to show the capability of PPT for quality assurance purposes. Finally, the saving on inspection time when using pulse phase thermography instead of ultrasonic testing is considered.

  5. Effect of stress on ultrasonic pulses in fiber reinforced composites

    NASA Technical Reports Server (NTRS)

    Hemann, J. H.; Baaklini, G. Y.

    1986-01-01

    An acoustical-ultrasonic technique was used to demonstrate relationships existing between changes in attenuation of stress waves and tensile stress on an eight ply 0 degree graphite-epoxy fiber reinforced composite. All tests were conducted in the linear range of the material for which no mechanical or macroscopic damage was evident. Changes in attenuation were measured as a function of tensile stress in the frequency domain and in the time domain. Stress wave propagation in these specimens was dispersive, i.e., the wave speed depends on frequency. Wave speeds varied from 267,400 cm/sec to 680,000 cm/sec as the frequency of the signal was varied from 150 kHz to 1.9 MHz which strongly suggests that flexural/lamb wave modes of propagation exist. The magnitude of the attenuation changes depended strongly on tensile stress. It was further observed that the wave speeds increased slightly for all tested frequencies as the stress was increased.

  6. An ultrasonic through-transmission technique for monitoring the setting of injectable calcium phosphate cement.

    PubMed

    Rajzer, Izabella; Piekarczyk, Wojciech; Castaño, Oscar

    2016-10-01

    An ultrasound through-transmission method to monitor the setting process of injectable calcium phosphate bone cements in body fluids is presented. This method can be used to determine the acoustic properties of the bone cement as it sets, which are linked to its material properties and provide some information about changes occurring within the cement. The development of the methodology of ultrasonic testing and execution of velocity measurements of the longitudinal and transverse waves using the through-transmission method made it possible to determine the material constants of samples during the setting and hardening process of an injectable cement paste in physiological fluids (i.e. the Young's modulus (E), the Poisson ratio (ν) and the shear modulus (G)), and to determine the degree of anisotropy of wave velocity in the samples. A strong advantage of the proposed method is that it is non-destructive, and the same sample can be used to monitor the whole process of the cement setting. The testing was performed on premixed and injectable calcium phosphate (CPC)/chitosan blend, where glycerol was used as a liquid phase. Comparisons between ultrasonic velocity and empirical tests such as compressive strength, porosity measurement, FTIR, SEM and XRD analysis at different days of immersion in Ringer's solutions showed that the ultrasonic velocity can be very useful to provide in situ information about changes occurring within the cement. PMID:27287094

  7. Evaluation of the transmission line model for couplant layer corrections in pulse-echo measurements.

    PubMed

    Sturtevant, Blake; Pantea, Cristian; Sinha, Dipen

    2013-05-01

    An acoustic couplant layer plays an integral role in many ultrasonic nondestructive testing and material characterization applications. It is important to account for this layer for accurate time-delay measurements. In pulse-echo measurements, the couplant layer can be accounted for by modeling the frequency dependence of phase delay. In this paper, two such models are evaluated for robustness in determining an accurate phase velocity: a simple linear relationship and the acoustic transmission line with its associated nonlinear expression. For this evaluation, measurements of acoustic phase delay in an aluminum sample were made by the pulse-echo method using tone bursts of 1800 different carrier frequencies between 35 and 125 MHz. The transmission line model was fit to the measured data using an unconstrained nonlinear least squares fitting routine with two free parameters: the acoustic phase velocity in the sample and the couplant thickness. It was found that this nonlinear model was extremely sensitive to the initial parameter guesses and could not unambiguously determine both the couplant layer thickness and acoustic phase velocity. In contrast, the faster and simpler linear least squares fit to the delay data determines a unique phase velocity in agreement with resonant ultrasound spectroscopy, an independent measurement technique. PMID:23661128

  8. Nano features of Al/Au ultrasonic bond interface observed by high resolution transmission electron microscopy

    SciTech Connect

    Ji Hongjun; Li Mingyu Kim, Jong-Myung; Kim, Dae-Won; Wang Chunqing

    2008-10-15

    Nano-scale interfacial details of ultrasonic AlSi1 wire wedge bonding to a Au/Ni/Cu pad were investigated using high resolution transmission electron microscopy (HRTEM). The intermetallic phase Au{sub 8}Al{sub 3} formed locally due to diffusion and reaction activated by ultrasound at the Al/Au bond interface. Multilayer sub-interfaces roughly parallel to the wire/pad interface were observed among this phase, and interdiffusional features near the Au pad resembled interference patterns, alternately dark and bright bars. Solid-state diffusion theory cannot be used to explain why such a thick compound formed within milliseconds at room temperature. The major formation of metallurgical bonds was attributed to ultrasonic cyclic vibration.

  9. A Digital Ultrasonic Pulse-Echo Overlap System and Algorithm for Unambiguous Determination of Pulse Transit Time

    SciTech Connect

    Cristian,P.; Rickel, D.; Migliori, A.; Zhang, J.; Zhao, Y.; Leisure, R.; Li, B.

    2005-01-01

    We report an evolution of an all-digital ultrasonic pulse technique for measurements of elastic constants of solids. An unambiguous analytical procedure is described for determining the correct time delay of echoes without any need for actual echo overlap. We also provide a simple procedure for making corrections for transducer-bond-induced phase shifts. The precision of a measurement made with this system at ambient temperature exceeds one part in 107 without the use of mixers, gates, time delays, and other complications normally associated with such measurements.

  10. Pulse compression in a time variant system with application to ultrasonic vibrometry.

    PubMed

    Martin, J S; Rogers, P H; Gray, M D

    2013-03-01

    Pulse compression is normally applied only to time-invariant systems, as the variation of a system's properties during its interrogation violates assumptions of the compression process. However, there is an exact solution to the pulse-compression problem when the time variance satisfies two criteria, which are the same as those required for the operation of an ultrasonic vibrometer in the context of a tissue elastography system. One is that the variations be very small in comparison with the wavelength of the interrogating ultrasound. The other is that the bandwidth of the variations be within one Nyquist band as sampled by the periodic interrogation signal. The solution to this problem involves a step-wise interpolation of the static pulse-compression transfer function in the frequency domain. This technique, in conjunction with the selection of an appropriate interrogation signal, offers significant advantages in measurement time or measurement resolution for an ultrasonic vibrometer limited by additive noise at the receiver. The characteristics of optimal interrogation signals for this technique are the signal's crest factor, spectral energy distribution, and phasing. These relate to the intended compression pulse, the noise, and the static response of the system. The technique has been demonstrated analytically, experimentally, and with numerical models. PMID:23464021

  11. Atomic library optimization for pulse ultrasonic sparse signal decomposition and reconstruction

    NASA Astrophysics Data System (ADS)

    Song, Shoupeng; Li, Yingxue; Dogandžić, Aleksandar

    2016-02-01

    Compressive sampling of pulse ultrasonic NDE signals could bring significant savings in the data acquisition process. Sparse representation of these signals using an atomic library is key to their interpretation and reconstruction from compressive samples. However, the obstacles to practical applicability of such representations are: large size of the atomic library and computational complexity of the sparse decomposition and reconstruction. To help solve these problems, we develop a method for optimizing the ranges of parameters of traditional Gabor-atom library to match a real pulse ultrasonic signal in terms of correlation. As a result of atomic-library optimization, the number of the atoms is greatly reduced. Numerical simulations compare the proposed approach with the traditional method. Simulation results show that both the time efficiency and signal reconstruction energy error are superior to the traditional one even with small-scale atomic library. The performance of the proposed method is also explored under different noise levels. Finally, we apply the proposed method to real pipeline ultrasonic testing data, and the results indicate that our reduced atomic library outperforms the traditional library.

  12. Transmission of ultrasonic waves at oblique incidence to composite laminates with spring-type interlayer interfaces.

    PubMed

    Ishii, Yosuke; Biwa, Shiro

    2015-11-01

    The transmission characteristics of ultrasonic waves at oblique incidence to composite laminates are analyzed theoretically by the stiffness matrix method. The analysis takes into account the presence of thin resin-rich regions between adjacent plies as spring-type interfaces with normal and shear stiffnesses. The amplitude transmission coefficient of longitudinal wave through a unidirectional laminate immersed in water is shown to be significantly influenced by the frequency, the interlayer interfacial stiffnesses, and the incident angle. Using Floquet's theorem, the dispersion relation of the infinitely extended laminate structure is calculated and compared to the transmission coefficient of laminates of finite thickness. This reveals that the ranges of frequency and interfacial stiffnesses where the Floquet waves lie in the band-gaps agree well with those where the transmission coefficient of the finite layered structure is relatively small, indicating that the band-gaps appear even in the laminate with a finite number of plies. The amplitude transmission coefficient for an 11-ply carbon-epoxy unidirectional composite laminate is experimentally obtained for various frequencies and incident angles. The low-transmission zones observed in the experimental results, which are due to the critical angle of the quasi-longitudinal wave and the Bragg reflection, are shown to be favorably compared with the theory. PMID:26627756

  13. Constant frequency pulsed phase-locked-loop instrument for measurement of ultrasonic velocity

    NASA Technical Reports Server (NTRS)

    Yost, William T.; Cantrell, John H.; Kushnick, Peter W.

    1991-01-01

    A new instrument based on a constant-frequency pulsed phase-locked-loop (CFPPLL) concept has been developed to accurately measure the ultrasonic wave velocity in liquids and changes in ultrasonic wave velocity in solids and liquids. An analysis of the system shows that it is immune to many of the frequency-dependent effects that plague other techniques. Measurements of the sound velocity in ultrapure water are used to confirm the analysis. The results are in excellent agreement with values from the literature, and establish that the CFPPLL provides a reliable, accurate way to measure velocities, as well as for monitoring small changes in velocity without the sensitivity to frequency-dependent phase shifts common to other measurement systems. The estimated sensitivity to phase changes is better than a few parts in 10 to the 7th.

  14. Multi-wave ultrasonic Doppler method for measuring high flow-rates using staggered pulse intervals

    NASA Astrophysics Data System (ADS)

    Muramatsu, Ei; Murakawa, Hideki; Sugimoto, Katsumi; Asano, Hitoshi; Takenaka, Nobuyuki; Furuichi, Noriyuki

    2016-02-01

    The ultrasonic pulsed Doppler method (UDM) can obtain a velocity profile along the path of an ultrasonic beam. However, the UDM measurement volume is relatively large and it is known that the measurement volume affects the measurement accuracy. In this study, the effect of the measurement volume on velocity and flow rate measurements is analytically and experimentally evaluated. The velocities measured using UDM are considered to be ensemble-averaged values over the measurement volume in order to analyze the velocity error due to the measurement volume, while the flow rates are calculated from the integration of the velocity profile across the pipe. The analytical results show that the channel width, i.e. the spatial resolution along the ultrasonic beam axis, rather than the ultrasonic beam diameter, strongly influences the flow rate measurement. To improve the accuracy of the flow rate, a novel method using a multi-wave ultrasonic transducer consisting of two piezo-electric elements with different basic frequencies is proposed to minimize the size of the measurement volume in the near-wall region of a pipe flow. The velocity profiles in the near-wall region are measured using an 8 MHz sensor with a small diameter, while those far from the transducer are measured using a hollow 2 MHz sensor in the multi-wave transducer. The applicability of the multi-wave transducer was experimentally investigated using the water flow-rate calibration facility at the National Institute of Advanced Industrial Science and Technology (AIST). As a result, the errors in the flow rate were found to be below  -1%, while the multi-wave method is shown to be particularly effective for measuring higher flow rates in a large-diameter pipe.

  15. Ultrasonics

    NASA Technical Reports Server (NTRS)

    Leonard, B. E.; Gardner, C. G.

    1973-01-01

    Ultrasonic testing is discussed as a primary means of nondestructive evaluation of subsurface flaws. The advantages and disadvantages are listed. The elementary principles, basic components of test units, scan modes, resonance testing, detection of fatigue cracks, monitoring fatigue crack growth, and determination of residual stress are discussed.

  16. [Visualization of blood flow in abdominal tumors by the ultrasonic pulsed Doppler method].

    PubMed

    Ueno, N; Yamanaka, T; Kimura, K

    1989-06-01

    The clinical utility of visualizing the blood flow in the margin and inside of tumors by ultrasonic pulsed Doppler method (UPDM) was evaluated in 54 patients (85 lesions) with various abdominal tumors. It was proved that UPDM was able to evaluate the vascularity of the tumor and the surrounding vascular system. These results indicate that this method may be applied clinically for judging the effects of and the indications for the transcatheter arterial embolization (TAE) therapy. It is also suggested that UPDM may be applied in the differential diagnosis of tumors according to the changes of blood velocity and wave patterns. PMID:2677449

  17. Spark ultrasonic transducer

    NASA Technical Reports Server (NTRS)

    Hoop, J. M.

    1972-01-01

    Nondestructive testing by spark transducer induces ultrasonic pulses in materials without physical contact. High power pulse generator connected to step up transformer produces sparking between two tungsten rods and ultrasonic energy pulses in test samples placed between rods.

  18. Assessment of strength properties of cemented paste backfill by ultrasonic pulse velocity test.

    PubMed

    Yılmaz, Tekin; Ercikdi, Bayram; Karaman, Kadir; Külekçi, Gökhan

    2014-07-01

    Ultrasonic pulse velocity (UPV) test is one of the most popular non-destructive techniques used in the assessment of the mechanical properties of concrete or rock materials. In this study, the effects of binder type/dosage, water to cement ratio (w/c) and fines content (<20 μm) of the tailings on ultrasonic pulse velocity (UPV) of cemented paste backfill (CPB) samples were investigated and correlated with the corresponding unconfined compressive strength (UCS) data. A total of 96 CPB samples prepared at different mixture properties were subjected to the UPV and UCS tests at 7, 14, 28 and 56-days of curing periods. UPV and UCS of CPB samples of ordinary Portland cement (CEM I 42.5 R) and sulphate resistant cement (SRC 32.5) initially increased rapidly, but, slowed down after 14 days. However, UPV and UCS of CPB samples of the blast furnace slag cement (CEM III/A 42.5 N) steadily increased between 7 and 56 days. Increasing binder dosage or reducing w/c ratio and fines content (<20 μm) increased the UCS and UPV of CPB samples. UPV was found to be particularly sensitive to fines content. UCS data were correlated with the corresponding UPV data. A linear relation appeared to exist between the UCS and UPV of CPB samples. These findings have demonstrated that the UPV test can be reliably used for the estimation of the strength of CPB samples. PMID:24602334

  19. Waveguide piezoelectric micromachined ultrasonic transducer array for short-range pulse-echo imaging

    NASA Astrophysics Data System (ADS)

    Lu, Y.; Tang, H.; Wang, Q.; Fung, S.; Tsai, J. M.; Daneman, M.; Boser, B. E.; Horsley, D. A.

    2015-05-01

    This paper presents an 8 × 24 element, 100 μm-pitch, 20 MHz ultrasound imager based on a piezoelectric micromachined ultrasonic transducer (PMUT) array having integrated acoustic waveguides. The 70 μm diameter, 220 μm long waveguides function both to direct acoustic waves and to confine acoustic energy, and also to provide mechanical protection for the PMUT array used for surface-imaging applications such as an ultrasonic fingerprint sensor. The imager consists of a PMUT array bonded with a CMOS ASIC using wafer-level conductive eutectic bonding. This construction allows each PMUT in the array to have a dedicated front-end receive amplifier, which together with on-chip analog multiplexing enables individual pixel read-out with high signal-to-noise ratio through minimized parasitic capacitance between the PMUT and the front-end amplifier. Finite element method simulations demonstrate that the waveguides preserve the pressure amplitude of acoustic pulses over distances of 600 μm. Moreover, the waveguide design demonstrated here enables pixel-by-pixel readout of the ultrasound image due to improved directivity of the PMUT by directing acoustic waves and creating a pressure field with greater spatial uniformity at the end of the waveguide. Pulse-echo imaging experiments conducted using a one-dimensional steel grating demonstrate the array's ability to form a two-dimensional image of a target.

  20. Stress wave attenuation in thin structures by ultrasonic through-transmission

    NASA Technical Reports Server (NTRS)

    Lee, S. S.; Williams, J. H., Jr.

    1980-01-01

    The steady state amplitude of the output of an ultrasonic through transmission measurement is analyzed and the result is given in closed form. Provided that the product of the input and output transduction ratios; the specimen-transducer reflection coefficient; the specimen-transducer phase shift parameter; and the material phase velocity are known, this analysis gives a means for determining the through-thickness attenuation of an individual thin sample. Multiple stress wave reflections are taken into account and so signal echoes do not represent a difficulty. An example is presented for a graphite fiber epoxy composite (Hercules AS/3501-6). A direct method for continuous or intermittent monitoring of through thickness attenuation of plate structures which may be subject to service structural degradation is provided.

  1. Stress-wave attenuation in thin structures by ultrasonic through-transmission

    NASA Technical Reports Server (NTRS)

    Lee, S. S.; Williams, J. H., Jr.

    1980-01-01

    The steady-state amplitude of the output of an ultrasonic through-transmission measurement is analyzed and the result is given in closed form. Provided that the product of the input and output transduction ratios, the specimen-transducer reflection coefficient, the specimen-transducer phase-shift parameter, and the material phase velocity are known, this analysis gives a means for determining the through-thickness attenuation of an individual thin sample. Multiple stress-wave reflections are taken into account, and so signal echoes do not represent a difficulty. An example is presented for a graphite fiber epoxy composite (Hercules AS/3501-6). Thus, the technique provides a direct method for continuous or intermittent monitoring of through-thickness attenuation of plate structures which may be subject to service structural degradation.

  2. Ultrasonic ranging and data telemetry system

    DOEpatents

    Brashear, Hugh R.; Blair, Michael S.; Phelps, James E.; Bauer, Martin L.; Nowlin, Charles H.

    1990-01-01

    An ultrasonic ranging and data telemetry system determines a surveyor's position and automatically links it with other simultaneously taken survey data. An ultrasonic and radio frequency (rf) transmitter are carried by the surveyor in a backpack. The surveyor's position is determined by calculations that use the measured transmission times of an airborne ultrasonic pulse transmitted from the backpack to two or more prepositioned ultrasonic transceivers. Once a second, rf communications are used both to synchronize the ultrasonic pulse transmission-time measurements and to transmit other simultaneously taken survey data. The rf communications are interpreted by a portable receiver and microcomputer which are brought to the property site. A video display attached to the computer provides real-time visual monitoring of the survey progress and site coverage.

  3. Ultrasonic Direction Measurement Method Using Sensitivity Compensated Transmitting Signal and Pulse Compression

    NASA Astrophysics Data System (ADS)

    Chimura, Dai; Toh, Ryo; Motooka, Seiichi

    We have studied high resolution pulse compression technique for ultrasonic pulse-echo measurement. To acquire broader and flatter spectrum, a Sensitivity Compensate Transmitting (SCT) signal was proposed. The SCT signal is calculated from inversed filtering of received signal. Here, two types SCT signal are proposed. As a Sensitivity Compensated AM (SCAM) signal, an amplitude modulated chirp wave is proposed. Furthermore, for higher Signal to Noise Ratio (SNR), a non-linear FM signal is proposed as a Sensitivity Compensate FM (SCFM) signal. In this paper, effectiveness of the SCT signal on 2-D direction measurement is discussed. By using the SCT signal, the time resolution of compressed pulse is improved, and accuracies of direction measurement using the SCT signal are improved than that of using the chirp wave. Furthermore, by using the SCFM signal, accuracy of direction measurement is improved than that of using the SCAM signal when the target is located at the position where the SNR of received signal is lower.

  4. An ultrasonic system for diameter pulse tracking in arteries: problems and pitfalls.

    PubMed

    Manor, D; Dahl, P; Benthin, M; Ruzicka, R; Lindström, K; Gennser, G

    1993-01-01

    Non-invasive ultrasonic techniques for measuring the mechanical behaviour of large arteries have a potential clinical application for physiological studies of the circulation and early detection of degenerative arterial disorders. A newly developed system for such purposes, comprising two double-echo trackers with zero-crossing phase-locked circuits and interfacing a B-mode real-time scanner, has been introduced for on-line recording of the diameter in a selected aortic segment. The aim of this report is to draw attention to the limitations of the technique in order to avoid misinterpretation of results. The various problems associated with the use of phase-locked echo followers for tracking sonic echoes of vessel pulse waves are summarized. The high spatial resolution of the measuring system is essential for estimating the elastic properties of the vessel, because the fractional changes of the diameter waveform during a heart cycle are small compared with the swings of intravascular pressure. Measuring errors may originate from either human or technical sources. From several viewpoints correct alignment of the ultrasonic beam vis-à-vis the vessel segment under consideration is crucial for obtaining valid measures. A thorough knowledge of the physics involved is essential for an adequate use of the instrument. With correct use, easily reproducible and reliable estimations are obtained of the mechanical properties of large vessel walls. PMID:8326507

  5. Development of an ultrasonic pulse-echo (UPE) technique for aircraft icing studies

    SciTech Connect

    Liu, Yang; Hu, Hui; Chen, Wen-Li; Bond, Leonard J.

    2014-02-18

    Aircraft operating in some cold weather conditions face the risk of icing. Icing poses a threat to flight safety and its management is expensive. Removing light frost on a clear day from a medium-size business jet can cost $300, heavy wet snow removal can cost $3,000 and removal of accumulated frozen/freezing rain can cost close to $10,000. Understanding conditions that lead to severe icing events is important and challenging. When an aircraft or rotorcraft flies in a cold climate, some of the super cooled droplets impinging on exposed aircraft surfaces may flow along the surface prior to freezing and give various forms and shapes of ice. The runback behavior of a water film on an aircraft affects the morphology of ice accretion and the rate of formation. In this study, we report the recent progress to develop an Ultrasonic Pulse-Echo (UPE) technique to provide real-time thickness distribution measurements of surface water flows driven by boundary layer airflows for aircraft icing studies. A series of initial experimental investigations are conducted in an ice wind tunnel employing an array of ultrasonic transducers placed underneath the surface of a flat plate. The water runback behavior on the plate is evaluated by measuring the thickness profile variation of the water film along the surface by using the UPE technique under various wind speed and flow rate conditions.

  6. Finite element modeling of ultrasonic waves produced by a pulsed laser

    SciTech Connect

    Dike, J.J.

    1998-03-01

    As part of an effort to apply laser ultrasonics to stress evaluation, sequential thermal and mechanical finite element analyses were used to simulate heating a region of an aluminum surface by a laser pulse and the stress waves that result. As residual or applied stresses can be related to changes in wave velocities, time-of-flight measurements may be used to determine the stresses. The goal of the effort is to improve time-of-flight measurements, and therefore resolution of the calculated stresses, using calculated waveform shapes in model-based signal processing techniques. Detailed finite element simulations of laser ultrasonics may also be used to aid development of techniques that can generate narrow band ultrasound. Because penetration of Rayleigh waves is frequency dependent, they can be used to obtain information about gradients near a surface. If the frequency of the laser generated Rayleigh waves can be controlled, laser ultrasound becomes a more useful tool for examining gradients in material properties or stresses at the surface of a part. Presented here are some preliminary finite element simulations of laser generation of ultrasound waves. Techniques for using commercial finite element codes are discussed and calculated displacement histories are presented for epicentral and same surface locations. These displacement histories are compared with results from the literature.

  7. Development of an ultrasonic pulse-echo (UPE) technique for aircraft icing studies

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Chen, Wen-Li; Bond, Leonard J.; Hu, Hui

    2014-02-01

    Aircraft operating in some cold weather conditions face the risk of icing. Icing poses a threat to flight safety and its management is expensive. Removing light frost on a clear day from a medium-size business jet can cost 300, heavy wet snow removal can cost 3,000 and removal of accumulated frozen/freezing rain can cost close to 10,000. Understanding conditions that lead to severe icing events is important and challenging. When an aircraft or rotorcraft flies in a cold climate, some of the super cooled droplets impinging on exposed aircraft surfaces may flow along the surface prior to freezing and give various forms and shapes of ice. The runback behavior of a water film on an aircraft affects the morphology of ice accretion and the rate of formation. In this study, we report the recent progress to develop an Ultrasonic Pulse-Echo (UPE) technique to provide real-time thickness distribution measurements of surface water flows driven by boundary layer airflows for aircraft icing studies. A series of initial experimental investigations are conducted in an ice wind tunnel employing an array of ultrasonic transducers placed underneath the surface of a flat plate. The water runback behavior on the plate is evaluated by measuring the thickness profile variation of the water film along the surface by using the UPE technique under various wind speed and flow rate conditions.

  8. Pulse-echo ultrasonic imaging method for eliminating sample thickness variation effects

    NASA Technical Reports Server (NTRS)

    Roth, Don J. (Inventor)

    1995-01-01

    A pulse-echo, immersion method for ultrasonic evaluation of a material is discussed. It accounts for and eliminates nonlevelness in the equipment set-up and sample thickness variation effects employs a single transducer, automatic scanning and digital imaging to obtain an image of a property of the material, such as pore fraction. The nonlevelness and thickness variation effects are accounted for by pre-scan adjusments of the time window to insure that the echoes received at each scan point are gated in the center of the window. This information is input into the scan file so that, during the automatic scanning for the material evaluation, each received echo is centered in its time window. A cross-correlation function calculates the velocity at each scan point, which is then proportionalized to a color or grey scale and displayed on a video screen.

  9. A comparative study of experimental and simulated ultrasonic pulse-echo signals from multilayered structures

    NASA Technical Reports Server (NTRS)

    Abedin, M. N.; Prabhu, D. R.; Winfree, W. P.; Johnston, P. H.

    1992-01-01

    The effect on the system acoustic response of variations in the adhesive thickness, coupling thickness, and paint thickness is considered. Both simulations and experimental measurements are used to characterize and classify A-scans from test regions, and to study the effects of various parameters such as paint thickness and epoxy thickness on the variations in the reflected signals. A 1D model of sound propagation in multilayered structures is used to verify the validity of the measured signals, and is also used to computationally generate signals for a class of test locations with gradually varying parameters. This approach exploits the ability of numerical simulations to provide a good understanding of the ultrasonic pulses reflected at disbonds.

  10. Highly sensitive simple homodyne phase detector for ultrasonic pulse-echo measurements

    DOE PAGESBeta

    Grossman, John; Suslov, Alexey V.; Yong, Grace; Boatner, Lynn A.; Svitelskiy, Oleksiy

    2016-04-07

    Progress in microelectronic technology has allowed us to design and develop a simple but, professional quality instrument for ultrasonic pulse-echo probing of the elastic properties of materials. The heart of this interfer- ometer lies in the AD8302 microchip, a gain and phase detector from Analog Devices, Inc. The interferometer was tested by measuring the temperature dependences of the ultrasound speed and attenuation in a ferro- electric KTa0.92 Nb0.08O3 (KTN) crystal at a frequency of about 40 MHz. These tests demonstrated that our instrument is capable of detecting the relative changes in the sound speed v on the level of Δv/vmore » ~ 10–7. In addition, the ultrasound attenuation revealed new features in the development of the low-temperature structure of the ferroelectric KTN crystal.« less

  11. Pulse-Echo Ultrasonic Imaging Method for Eliminating Sample Thickness Variation Effects

    NASA Technical Reports Server (NTRS)

    Roth, Don J. (Inventor)

    1997-01-01

    A pulse-echo, immersion method for ultrasonic evaluation of a material which accounts for and eliminates nonlevelness in the equipment set-up and sample thickness variation effects employs a single transducer and automatic scanning and digital imaging to obtain an image of a property of the material, such as pore fraction. The nonlevelness and thickness variation effects are accounted for by pre-scan adjustments of the time window to insure that the echoes received at each scan point are gated in the center of the window. This information is input into the scan file so that, during the automatic scanning for the material evaluation, each received echo is centered in its time window. A cross-correlation function calculates the velocity at each scan point, which is then proportionalized to a color or grey scale and displayed on a video screen.

  12. Hydraulic Fracture Propagation through Preexisting Discontinuity Monitored by Acoustic Emission and Ultrasonic Transmission

    NASA Astrophysics Data System (ADS)

    Stanchits, S.; Lund, J.; Surdi, A.; Edelman, E.; Whitney, N.; Eldredge, R.; Suarez-Rivera, R.

    2011-12-01

    Hydraulic fracturing is critical to enhance hydrocarbon production from ultra-low permeability unconventional reservoirs, and is the common completion methodology for tight formations around the world. Unfortunately, these reservoirs are often highly heterogeneous and their heterogeneity imparts a degree of geometrical complexity in hydraulic fractures that is poorly understood. Fracture complexity (e.g. branching) results in higher surface area and could be beneficial to production provided it remains conductive. Understanding the sources and consequences of fracture complexity is thus of high importance to completion and production operations. In this study we postulate that textural complexity in tight heterogeneous formations induces fracture complexity, and that the main sources of textural complexity are associated with veins, bed boundaries, lithologic contacts, and geologic interfaces. We thus study the effect of interfaces on hydraulic fracture propagation under laboratory conditions by Acoustic Emission (AE) and Ultrasonic Transmission (UT) monitoring techniques. The experiments were conducted on low permeability sandstone blocks of 279 x 279 x 381 mm length with saw cut discontinuities oriented orthogonally to the expected direction of fracture propagation. The rock is loaded in a poly-axial test frame to representative effective in-situ stress conditions of normal and deviatoric stress. Hydraulic fracturing was initiated by injection of silicon oil into a borehole drilled off center from the block. Acoustic emission (AE) events were continuously monitored during testing using nineteen P-wave sensors. Additional sensors were installed to periodically monitor ultrasonic transmission (UT) along various directions oblique and perpendicular to the fracture and the interface. The AE and UT data were recorded using a Vallen AMSY-6 system, with 16-bit amplitude resolution and 5 MHz sampling rate. Detailed analysis of AE localizations allowed us to identify

  13. Three-dimensional simulations of ultrasonic axial transmission velocity measurement on cortical bone models

    NASA Astrophysics Data System (ADS)

    Bossy, Emmanuel; Talmant, Maryline; Laugier, Pascal

    2004-05-01

    The ultrasonic axial transmission technique, used to assess cortical shells of long bones, is investigated using numerical simulations based on a three-dimensional (3D) finite difference code. We focus our interest on the effects of 3D cortical bone geometry (curvature, cortical thickness), anisotropy, and microporosity on speed of sound (SOS) measurements for different frequencies in the MHz range. We first show that SOS values measured on tubular cortical shells are identical to those measured on cortical plates of equal thickness. Anisotropy of cortical bone is then shown to have a major impact on SOS measurement as a function of cortical thickness. The range of SOS values measured on anisotropic bone is half the range found when bone is considered isotropic. Dependence of thickness occurs for cortical shell thinner than 0.5×λbone in anisotropic bone (λbone: wavelength in bone), whereas it occurs for cortical shell thinner than λbone when anisotropy is neglected. Sensitivity of SOS along the bone axis to intracortical microporosity is shown to be approximately -20 m s-1 per percent of porosity. Using homogenized porous bone, we finally show that the cortical depth that contributes to lateral wave SOS measurement is approximately 1-1.5 mm for frequencies ranging from 500 kHz to 2 MHz under classical in vivo measurement conditions.

  14. Multiband tissue classification for ultrasonic transmission tomography using spectral profile detection

    NASA Astrophysics Data System (ADS)

    Jeong, Jeong-Won; Kim, Tae-Seong; Shin, Dae-Chul; Do, Synho; Marmarelis, Vasilis Z.

    2004-04-01

    Recently it was shown that soft tissue can be differentiated with spectral unmixing and detection methods that utilize multi-band information obtained from a High-Resolution Ultrasonic Transmission Tomography (HUTT) system. In this study, we focus on tissue differentiation using the spectral target detection method based on Constrained Energy Minimization (CEM). We have developed a new tissue differentiation method called "CEM filter bank". Statistical inference on the output of each CEM filter of a filter bank is used to make a decision based on the maximum statistical significance rather than the magnitude of each CEM filter output. We validate this method through 3-D inter/intra-phantom soft tissue classification where target profiles obtained from an arbitrary single slice are used for differentiation in multiple tomographic slices. Also spectral coherence between target and object profiles of an identical tissue at different slices and phantoms is evaluated by conventional cross-correlation analysis. The performance of the proposed classifier is assessed using Receiver Operating Characteristic (ROC) analysis. Finally we apply our method to classify tiny structures inside a beef kidney such as Styrofoam balls (~1mm), chicken tissue (~5mm), and vessel-duct structures.

  15. Soft tissue differentiation using multiband signatures of high resolution ultrasonic transmission tomography.

    PubMed

    Jeong, Jeong-Won; Kim, Tae-Seong; Shin, Dae C; Do, Synho; Singh, Manbir; Marmarelis, Vasilis Z

    2005-03-01

    In this paper, we are interested in soft tissue differentiation by multiband images obtained from the High-Resolution Ultrasonic Transmission Tomography (HUTT) system using a spectral target detection method based on constrained energy minimization (CEM). We have developed a new tissue differentiation method (called "CEM filter bank") consisting of multiple CEM filters specially designed for detecting multiple types of tissues. Statistical inference on the output of the CEM filter bank is used to make a decision based on the maximum statistical significance rather than the magnitude of each CEM filter output. We test and validate this method through three-dimensional interphantom/intraphantom soft tissue classification where target profiles obtained from an arbitrary single slice are used for differentiation over multiple other tomographic slices. The performance of the proposed classifier is assessed using receiver operating characteristic analysis. We also apply our method to classify tiny structures inside a bovine kidney and sheep kidneys. Using the proposed method we can detect physical objects and biological tissues such as styrofoam balls, chicken tissue, calyces, and vessel-duct successfully. PMID:15754990

  16. Measurement of guided mode wavenumbers in soft tissue-bone mimicking phantoms using ultrasonic axial transmission.

    PubMed

    Chen, Jiangang; Foiret, Josquin; Minonzio, Jean-Gabriel; Talmant, Maryline; Su, Zhongqing; Cheng, Li; Laugier, Pascal

    2012-05-21

    Human soft tissue is an important factor that influences the assessment of human long bones using quantitative ultrasound techniques. To investigate such influence, a series of soft tissue-bone phantoms (a bone-mimicking plate coated with a layer of water, glycerol or silicon rubber) were ultrasonically investigated using a probe with multi-emitter and multi-receiver arrays in an axial transmission configuration. A singular value decomposition signal processing technique was applied to extract the frequency-dependent wavenumbers of several guided modes. The results indicate that the presence of a soft tissue-mimicking layer introduces additional guided modes predicted by a fluid waveguide model. The modes propagating in the bone-mimicking plate covered by the soft-tissue phantom are only slightly modified compared to their counterparts in the free bone-mimicking plate, and they are still predicted by an elastic transverse isotropic two-dimensional waveguide. Altogether these observations suggest that the soft tissue-bone phantoms can be modeled as two independent waveguides. Even in the presence of the overlying soft tissue-mimicking layer, the modes propagating in the bone-mimicking plate can still be extracted and identified. These results suggest that our approach can be applied for the purpose of the characterization of the material and structural properties of cortical bone. PMID:22538382

  17. 3-D Surface Depression Profiling Using High Frequency Focused Air-Coupled Ultrasonic Pulses

    NASA Technical Reports Server (NTRS)

    Roth, Don J.; Kautz, Harold E.; Abel, Phillip B.; Whalen, Mike F.; Hendricks, J. Lynne; Bodis, James R.

    1999-01-01

    Surface topography is an important variable in the performance of many industrial components and is normally measured with diamond-tip profilometry over a small area or using optical scattering methods for larger area measurement. This article shows quantitative surface topography profiles as obtained using only high-frequency focused air-coupled ultrasonic pulses. The profiles were obtained using a profiling system developed by NASA Glenn Research Center and Sonix, Inc (via a formal cooperative agreement). (The air transducers are available as off-the-shelf items from several companies.) The method is simple and reproducible because it relies mainly on knowledge and constancy of the sound velocity through the air. The air transducer is scanned across the surface and sends pulses to the sample surface where they are reflected back from the surface along the same path as the incident wave. Time-of-flight images of the sample surface are acquired and converted to depth/surface profile images using the simple relation (d = V*t/2) between distance (d), time-of-flight (t), and the velocity of sound in air (V). The system has the ability to resolve surface depression variations as small as 25 microns, is useable over a 1.4 mm vertical depth range, and can profile large areas only limited by the scan limits of the particular ultrasonic system. (Best-case depth resolution is 0.25 microns which may be achievable with improved isolation from vibration and air currents.) The method using an optimized configuration is reasonably rapid and has all quantitative analysis facilities on-line including 2-D and 3-D visualization capability, extreme value filtering (for faulty data), and leveling capability. Air-coupled surface profilometry is applicable to plate-like and curved samples. In this article, results are shown for several proof-of-concept samples, plastic samples burned in microgravity on the STS-54 space shuttle mission, and a partially-coated cylindrical ceramic

  18. Continued Evaluation of the Pulse-Echo Ultrasonic Instrument for Critical Velocity Determination during Hanford Tank Waste Transfer Operations

    SciTech Connect

    Denslow, Kayte M.; Bontha, Jagannadha R.; Adkins, Harold E.; Jenks, Jeromy WJ; Burns, Carolyn A.; Schonewill, Philip P.; Hopkins, Derek F.; Thien, Michael G.; Wooley, Theodore A.

    2012-04-01

    Laboratory (PNNL) conducted an extensive evaluation of the ability of three ultrasonic instruments to detect critical velocity for a broad range of simulated Hanford nuclear waste streams containing particles with mean particle sizes of >50 microns. Evaluations were perform using the pipe loop at the Process Development Laboratory – East (PDL-E) at PNNL that was designed and built to evaluate the pipeline plugging issue during slurry transfer operations at the Hanford Waste Treatment Plant. In 2011 the ability of the ultrasonic PulseEcho system to detect critical velocity continued to be evaluated using the PDL-E flow loop and new simulants containing high-density particles with a mean particle size of < 15 microns. The PDL-E flow loop was modified for the 2011 testing to include a new test section that contained 5-MHz and 10-MHz ultrasonic transducers non-invasively mounted to schedule 40 pipe. The test section also contained reference instrumentation to facilitate direct comparison of the real-time PulseEcho transducer responses with experimentally observed critical velocities. This paper presents the results from the 2011 PulseEcho evaluation using a variety of simulated Hanford nuclear waste streams that were selected to encompass the expected high-level waste feed properties.

  19. Highly sensitive simple homodyne interferometer for ultrasonic pulse-echo measurements

    DOE PAGESBeta

    Grossman, John; Suslov, A. V.; Yong, G.; Boatner, Lynn A; Svitelskiy, O.

    2016-01-01

    Progress in microelectronic technology has allowed us to design and develop a simple but, professional quality instrument for ultrasonic pulse-echo probing of the elastic properties of materials. The heart of this interfer- ometer lies in the AD8302 microchip, a gain and phase detector from Analog Devices, Inc. The interferometer was tested by measuring the temperature dependences of the ultrasound speed and attenuation in a ferro- electric KTa0.92 Nb0.08 O3 (KTN) crystal at a frequency of about 40 MHz. These tests demonstrated that our instrument is capable of detecting the relative changes in the sound speed v on the level ofmore » v/v 10 7 . Moreover, this low-cost instrument was able to reveal previously unresolved feature - e.g. the theoretically expected velocity kink at the KTN phase transition to orthorhombic symmetry. Additionally, the ultrasound attenuation revealed new features in the development of the low-temperature structure of the ferroelectric KTN crystal.« less

  20. Highly sensitive simple homodyne interferometer for ultrasonic pulse-echo measurements

    SciTech Connect

    Grossman, John; Suslov, A. V.; Yong, G.; Boatner, Lynn A; Svitelskiy, O.

    2016-01-01

    Progress in microelectronic technology has allowed us to design and develop a simple but, professional quality instrument for ultrasonic pulse-echo probing of the elastic properties of materials. The heart of this interfer- ometer lies in the AD8302 microchip, a gain and phase detector from Analog Devices, Inc. The interferometer was tested by measuring the temperature dependences of the ultrasound speed and attenuation in a ferro- electric KTa0.92 Nb0.08 O3 (KTN) crystal at a frequency of about 40 MHz. These tests demonstrated that our instrument is capable of detecting the relative changes in the sound speed v on the level of v/v 10 7 . Moreover, this low-cost instrument was able to reveal previously unresolved feature - e.g. the theoretically expected velocity kink at the KTN phase transition to orthorhombic symmetry. Additionally, the ultrasound attenuation revealed new features in the development of the low-temperature structure of the ferroelectric KTN crystal.

  1. Increased range of ultrasonic guided wave testing of overhead transmission line cables using dispersion compensation.

    PubMed

    Legg, Mathew; Yücel, Mehmet K; Kappatos, Vassilios; Selcuk, Cem; Gan, Tat-Hean

    2015-09-01

    Overhead Transmission Line (OVTL) cables can experience structural defects and are, therefore, inspected using Non-Destructive Testing (NDT) techniques. Ultrasonic Guided Waves (UGW) is one NDT technique that has been investigated for inspection of these cables. For practical use, it is desirable to be able to inspect as long a section of cable as possible from a single location. This paper investigates increasing the UGW inspection range on Aluminium Conductor Steel Reinforced (ACSR) cables by compensating for dispersion using dispersion curve data. For ACSR cables, it was considered to be difficult to obtain accurate dispersion curves using modelling due to the complex geometry and unknown coupling between wire strands. Group velocity dispersion curves were, therefore, measured experimentally on an untensioned, 26.5m long cable and a method of calculating theoretical dispersion curves was obtained. Attenuation and dispersion compensation were then performed for a broadband Maximum Length Sequence (MLS) excitation signal. An increase in the Signal to Noise Ratio (SNR) of about 4-8dB compared to that of the dispersed signal was obtained. However, the main benefit was the increased ability to resolve the individual echoes from the end of the cable and an introduced defect in the form of a cut, which was 7 to at least 13dB greater than that of the dispersed signal. Five echoes were able to be clearly detected using MLS excitation signal, indicating the potential for an inspection range of up to 130m in each direction. To the best of the authors knowledge, this is the longest inspection range for ACSR cables reported in the literature, where typically cables, which were only one or two meter long, have been investigated previously. Narrow band tone burst and Hann windowed tone burst excitation signal also showed increased SNR and ability to resolve closely spaced echoes. PMID:25991388

  2. Fiber Optic Picosecond Laser Pulse Transmission Line for Hydrogen Ion Beam Profile Measurement

    SciTech Connect

    Liu, Yun; Huang, Chunning; Aleksandrov, Alexander V

    2013-01-01

    We present a fiber optic laser pulse transmission line for non-intrusive longitudinal profile measurement of the hydrogen ion (H-) beam at the front-end of the Spallation Neutron Source (SNS) accelerator. The 80.5 MHz, 2.5 ps, multi-killowatt optical pulses are delivered to the accelerator beam line through a large mode area polarization maintaining optical fiber to ensure a high measurement stability. The transmission efficiency, output laser beam quality, pulse jitter and pulse width broadening over a 100-ft fiber line are experimentally investigated. A successful measurement of the H- beam microbunch (~130 ps) profile is obtained. Our experiment is the first demonstration of particle beam profile diagnostics using fiber optic laser pulse transmission line.

  3. Decoupling of Getting Up Detection Device Using Ultrasonic Radar by Changing Duty Ratio of Transmission Wave

    NASA Astrophysics Data System (ADS)

    Yamada, Yo; Tanaka, Kanya; Haruyama, Kazuo; Wakasa, Yuji; Akashi, Takuya

    The decline in the quality of patient's safety control is a problem, because the number of caretakers is reduced by the acceleration of demographic aging in an elder care facility. Especially, the detection of getting up from the bed is very important for preventing patients from falling and wandering unbreakable. In our previous study, we have developed the getting up detection device with an ultrasonic radar, which is safe, cheap, and break-proof. However, if there are many patients in a ward, it is difficult to use some ultrasonic radars. The reason is that if some ultrasonic radars, which have the same frequency, are used in same ward, the ultrasonic signals are coherent with each other. To solve this problem, we propose a novel incoherent method. This method is achieved by improving the software in the device at a low cost.

  4. Finger blood content, light transmission, and pulse oximetry errors.

    PubMed

    Craft, T M; Lawson, R A; Young, J D

    1992-01-01

    The changes in light emitting diode current necessary to maintain a constant level of light incident upon a photodetector were measured in 20 volunteers at the two wavelengths employed by pulse oximeters. Three states of finger blood content were assessed; exsanguinated, hyperaemic, and normal. The changes in light emitting diode current with changes in finger blood content were small and are not thought to represent a significant source of error in saturation as measured by pulse oximetry. PMID:1536406

  5. Transmission errors and forward error correction in embedded differential pulse code modulation

    NASA Astrophysics Data System (ADS)

    Goodman, D. J.; Sundberg, C.-E.

    1983-11-01

    Formulas are derived for the combined effects of quantization and transmission errors on embedded Differential Pulse Code Modulation (DPCM) performance. The present analysis, which is both more general and precise than previous work on transmission errors in digital communication of analog signals, includes as its special cases the conventional DPCM and Pulse code Modulation. An SNR formula is obtained in which the effects of source characteristics and the effects of transmission characteristics are clearly distinguishable. Also given in computationally convenient form are specialized formulas applying to uncoded transmission through a random-error channel, transmission through a slowly fading channel, and transmission with all or part of the DCPM signal being protected by an error-correcting code.

  6. Real-time measurement of ice growth during simulated and natural icing conditions using ultrasonic pulse-echo techniques

    NASA Technical Reports Server (NTRS)

    Hansman, R. J., Jr.; Kirby, M. S.

    1986-01-01

    Results of tests to measure ice accretion in real-time using ultrasonic pulse-echo techniques are presented. Tests conducted on a 10.2 cm diameter cylinder exposed to simulated icing conditions in the NASA Lewis Icing Research Tunnel and on an 11.4 cm diameter cylinder exposed to natural icing conditions in flight are described. An accuracy of + or - 0.5 mm is achieved for real-time ice thickness measurements. Ice accretion rate is determined by differentiating ice thickness with respect to time. Icing rates measured during simulated and natural icing conditions are compared and related to icing cloud parameters. The ultrasonic signal characteristics are used to detect the presence of surface water on the accreting ice shape and thus to distinguish between dry ice growth and wet growth. The surface roughness of the accreted ice is shown to be related to the width of the echo signal received from the ice surface.

  7. Ultrasonic detection of photothermal interaction of lasers with tissue using a pulsed Doppler system

    NASA Astrophysics Data System (ADS)

    Ying, Hao; Azeemi, Aamer; Hartley, Craig J.; Motamedi, Massoud; Bell, Brent A.; Rastegar, Sohi; Sheppard, L. C.

    1995-05-01

    Thermal therapy using various heating sources such as lasers or microwaves to destroy benign and malignant lesions has recently gained widespread acceptance. However, the accurate prediction of thermal damage in tissue according to theoretical or computer modeling is difficult and unreliable due to target variability with respect to physical properties, geometry, and blood perfusion. Thus, one of the major obstacles to application of thermal therapies has been the lack of a noninvasive, real-time method that could determine the extent and geometry of treated tissue. To evaluate the effects of laser heating on tissue, we have developed an analog-digital hybrid Doppler ultrasound system to measure the phase and amplitude of ultrasonic echoes returned from the heated tissue. The system consists of an eight-gate pulsed Doppler detector, a 16-channel 12-bit A/D converter, and a signal analysis and visualization software package. In vitro studies using canine liver showed two distinct types of modulation of the echoes along the ultrasound beam path during laser irradiation using an 810 nm diode laser. Type 1 signals showed a small and slow variation in amplitude and phase, and were attributed to tissue coagulation. Type 1 signals showed a small and slow variation in amplitude and phase, and were attributed to tissue coagulation. Type 2 signals showed large and rapid variations in amplitude and phase which usually appeared after tissue surface explosion and were indicative of tissue ablation. We hypothesize that the observed phase changes in type 1 signals are due to thermal effects within the tissue consistent with tissue expansion and contraction while the phase changes in type 2 signals are likely due to formation and motion of gas bubbles in the tissue. A further development of the Doppler ultrasound technique could lead to the generation of feedback information needed for monitoring and automatic control of thermal treatment using various heating modalities such as

  8. Predicting the uniaxial compressive strength of cemented paste backfill from ultrasonic pulse velocity test

    NASA Astrophysics Data System (ADS)

    Yılmaz, Tekin; Ercikdi, Bayram

    2016-07-01

    The aim of this study is to investigate the predictability of the uniaxial compressive strength (UCS) of cemented paste backfill (CPB) prepared from three different tailings (Tailings T1, Tailings T2 and Tailings T3) using ultrasonic pulse velocity (UPV) test. For this purpose, 180 CPB samples with diameter × height of 5 × 10 cm (similar to NX size) prepared at different binder dosages and consistencies were subjected to the UPV and UCS tests at 7-56 days of curing periods. The effects of binder dosage and consistency on the UPV and UCS properties of CPB samples were investigated and UCS values were correlated with the corresponding UPV data. Microstructural analyses were also performed on CPB samples in order to understand the effect of microstructure (i.e. total porosity) on the UPV data. The UPV and UCSs of CPB samples increased with increasing binder dosage and reducing the consistency irrespective of the tailings type and curing periods. Changes in the mixture properties observed to have a lesser extent on the UPV properties of CPB, while, their effect on the UCS of CPB was significant. Empirical equations were produced for each mixture in order to predict the UCSs of CPB through UPV. The validity of the equations was also checked by t- and F-test. The results showed that a linear relation appeared to exist between the UPV and UCS with high correlation coefficients (r ≥ 0.79) and all models were valid by statistical analysis. Mercury intrusion porosimetry (MIP) and scanning electron microscope (SEM) analyses have revealed that the UPV properties of CPB samples were highly associated with their respective microstructural properties (i.e. total porosity). The major output of this study is that UPV test can be effectively used for a preliminary prediction of the strength of CPB.

  9. Applications of tunable high energy/pressure pulsed lasers to atmospheric transmission and remote sensing

    NASA Technical Reports Server (NTRS)

    Hess, R. V.; Seals, R. K.

    1974-01-01

    Atmospheric transmission of high energy C12 O2(16) lasers were improved by pulsed high pressure operation which, due to pressure broadening of laser lines, permits tuning the laser 'off' atmospheric C12 O2(16) absorption lines. Pronounced improvement is shown for horizontal transmission at altitudes above several kilometers, and for vertical transmission through the entire atmosphere. The atmospheric transmission of tuned C12 O2(16) lasers compares favorably with C12 O2(18) isotope lasers and CO lasers. The advantages of tunable, high energy, high pressure pulsed lasers over tunable diode lasers and waveguide lasers, in combining high energies with a large tuning range, are evaluated for certain applications to remote sensing of atmospheric constituents and pollutants. Pulsed operation considerably increases the signal to noise ratio without seriously affecting the high spectral resolution of signal detection obtained with laser heterodyning.

  10. Method and apparatus for ultrasonic doppler velocimetry using speed of sound and reflection mode pulsed wideband doppler

    DOEpatents

    Shekarriz, Alireza; Sheen, David M.

    2000-01-01

    According to the present invention, a method and apparatus rely upon tomographic measurement of the speed of sound and fluid velocity in a pipe. The invention provides a more accurate profile of velocity within flow fields where the speed of sound varies within the cross-section of the pipe. This profile is obtained by reconstruction of the velocity profile from the local speed of sound measurement simultaneously with the flow velocity. The method of the present invention is real-time tomographic ultrasonic Doppler velocimetry utilizing a to plurality of ultrasonic transmission and reflection measurements along two orthogonal sets of parallel acoustic lines-of-sight. The fluid velocity profile and the acoustic velocity profile are determined by iteration between determining a fluid velocity profile and measuring local acoustic velocity until convergence is reached.

  11. Ultrasonic probe deployment device for increased wave transmission and rapid area scan inspections

    SciTech Connect

    DiMambro, Joseph; Roach, Dennis P; Rackow, Kirk A; Nelson, Ciji L; Dasch, Cameron J; Moore, David G

    2013-02-12

    An ultrasonic probe deployment device in which an ultrasound-transmitting liquid forms the portion of the ultrasonic wave path in contact with the surface being inspected (i.e., the inspection surface). A seal constrains flow of the liquid, for example preventing the liquid from surging out and flooding the inspection surface. The seal is not rigid and conforms to variations in the shape and unevenness of the inspection surface, thus forming a seal (although possibly a leaky seal) around the liquid. The probe preferably is held in place to produce optimum ultrasonic focus on the area of interest. Use of encoders can facilitate the production of C-scan area maps of the material being inspected.

  12. Ultrasonic probe deployment device for increased wave transmission and rapid area scan inspections

    SciTech Connect

    DiMambro, Joseph; Roach, Dennis P.; Rackow, Kirk A.; Nelson, Ciji L.; Dasch, Cameron J.; Moore, David G.

    2012-01-03

    An ultrasonic probe deployment device in which an ultrasound-transmitting liquid forms the portion of the ultrasonic wave path in contact with the surface being inspected (i.e., the inspection surface). A seal constrains flow of the liquid, for example preventing the liquid from surging out and flooding the inspection surface. The seal is not rigid and conforms to variations in the shape and unevenness of the inspection surface, thus forming a seal (although possibly a leaky seal) around the liquid. The probe preferably is held in place to produce optimum ultrasonic focus on the area of interest. Use of encoders can facilitate the production of C-scan area maps of the material being inspected.

  13. Pulse-Echo Phased Array Ultrasonic Inspection of Pultruded Rod Stitched Efficient Unitized Structure (PRSEUS)

    NASA Technical Reports Server (NTRS)

    Johnston, Pat H.

    2010-01-01

    A PRSEUS test article was subjected to controlled impact on the skin face followed by static and cyclic axial compressions. Phased array ultrasonic inspection was conducted before impact, and after each of the test conditions. A linear phased array probe with a manual X-Y scanner was used for interrogation. Ultrasound showed a delamination between the skin and stringer flange adjacent to the impact. As designed, the stitching in the flange arrested the lateral flaw formation. Subsequent ultrasonic data showed no delamination growth due to continued loading. Keywords: Phased Array, Ultrasonics, Composites, Out-of-Autoclave

  14. Continued Evaluation of the Pulse-Echo Ultrasonic Instrument for Critical Velocity Determination during Hanford Tank Waste Transfer Operations - 12518

    SciTech Connect

    Denslow, Kayte M.; Bontha, Jagannadha R.; Adkins, Harold E.; Jenks, Jeromy W.J.; Burns, Carolyn A.; Schonewill, Philip P.; Hopkins, Derek F.; Thien, Michael G.; Wooley, Theodore A.

    2012-07-01

    The delivery of Hanford double-shell tank waste to the Hanford Tank Waste Treatment and Immobilization Plant (WTP) will be governed by specific Waste Acceptance Criteria that are identified in ICD 19 - Interface Control Document for Waste Feed. Waste must be certified as acceptable before it can be delivered to the WTP. The fluid transfer velocity at which solid particulate deposition occurs in waste slurry transport piping (critical velocity) is a key waste parameter that must be accurately characterized to determine if the waste is acceptable for transfer to the WTP. In 2010 Washington River Protection Solutions and the Pacific Northwest National Laboratory began evaluating the ultrasonic PulseEcho instrument to accurately identify critical velocities in a horizontal slurry transport pipeline for slurries containing particles with a mean particle diameter of >50 micrometers. In 2011 the PulseEcho instrument was further evaluated to identify critical velocities for slurries containing fast-settling, high-density particles with a mean particle diameter of <15 micrometers. This two-year evaluation has demonstrated the ability of the ultrasonic PulseEcho instrument to detect the onset of critical velocity for a broad range of physical and rheological slurry properties that are likely encountered during the waste feed transfer operations between the Hanford tank farms and the WTP. (authors)

  15. High pulse repetition frequency, multiple wavelength, pulsed CO(2) lidar system for atmospheric transmission and target reflectance measurements.

    PubMed

    Ben-David, A; Emery, S L; Gotoff, S W; D'Amico, F M

    1992-07-20

    A multiple wavelength, pulsed CO(2) lidar system operating at a pulse repetition frequency of 200 Hz and permitting the random selection of CO(2) laser wavelengths for each laser pulse is presented. This system was employed to measure target reflectance and atmospheric transmission by using laser pulse bursts consisting of groups with as many as 16 different wavelengths at a repetition rate of 12 Hz. The wavelength tuning mechanism of the transversely excited atmospheric laser consists of a stationary grating and a flat mirror controlled by a galvanometer. Multiple wavelength, differential absorption lidar (DIAL) measurements reduce the effects of differential target reflectance and molecular absorption interference. Examples of multiwavelength DIAL detection for ammonia and water vapor show the dynamic interaction between these two trace gases. Target reflectance measurements for maple trees in winter and autumn are presented. PMID:20725406

  16. Pulse-excited, auto-zeroing multiple channel data transmission system

    DOEpatents

    Fasching, George E.

    1987-01-01

    A multiple channel data transmission system is provided in which signals from a plurality of pulse operated transducers and a corresponding plurality of pulse operated signal processor channels are multiplexed for single channel FM transmission to a receiving station. The transducers and corresponding channel amplifiers are powered by pulsing the dc battery power to these devices to conserve energy and battery size for long-term data transmission from remote or inaccessible locations. Auto zeroing of the signal channel amplifiers to compensate for drift associated with temperature changes, battery decay, component aging, etc., in each channel is accomplished by means of a unique auto zero feature which between signal pulses holds a zero correction voltage on an integrating capacitor coupled to the corresponding channel amplifier output. Pseudo-continuous outputs for each channel are achieved by pulsed sample-and-hold circuits which are updated at the pulsed operation rate. The sample-and-hold outputs are multiplexed into an FM/FM transmitter for transmission to an FM receiver station for demultiplexing and storage in separate channel recorders.

  17. Pulse-excited, auto-zeroing multiple channel data transmission system

    DOEpatents

    Fasching, G.E.

    1985-02-22

    A multiple channel data transmission system is provided in which signals from a plurality of pulse operated transducers and a corresponding plurality of pulse operated signal processor channels are multiplexed for single channel FM transmission to a receiving station. The transducers and corresponding channel amplifiers are powered by pulsing the dc battery power to these devices to conserve energy and battery size for long-term data transmission from remote or inaccessible locations. Auto zeroing of the signal channel amplifiers to compensate for drift associated with temperature changes, battery decay, component aging, etc., in each channel is accomplished by means of a unique auto zero feature which between signal pulses holds a zero correction voltage on an integrating capacitor coupled to the corresponding channel amplifier output. Pseudo-continuous outputs for each channel are achieved by pulsed sample-and-hold circuits which are updated at the pulsed operation rate. The sample-and-hold outputs are multiplexed into an FM/FM transmitter for transmission to an FM receiver station for demultiplexing and storage in separate channel recorders.

  18. Full circuit calculation for electromagnetic pulse transmission in a high current facility

    NASA Astrophysics Data System (ADS)

    Zou, Wenkang; Guo, Fan; Chen, Lin; Song, Shengyi; Wang, Meng; Xie, Weiping; Deng, Jianjun

    2014-11-01

    We describe herein for the first time a full circuit model for electromagnetic pulse transmission in the Primary Test Stand (PTS)—the first TW class pulsed power driver in China. The PTS is designed to generate 8-10 MA current into a z -pinch load in nearly 90 ns rise time for inertial confinement fusion and other high energy density physics research. The PTS facility has four conical magnetic insulation transmission lines, in which electron current loss exists during the establishment of magnetic insulation. At the same time, equivalent resistance of switches and equivalent inductance of pinch changes with time. However, none of these models are included in a commercially developed circuit code so far. Therefore, in order to characterize the electromagnetic transmission process in the PTS, a full circuit model, in which switch resistance, magnetic insulation transmission line current loss and a time-dependent load can be taken into account, was developed. Circuit topology and an equivalent circuit model of the facility were introduced. Pulse transmission calculation of shot 0057 was demonstrated with the corresponding code FAST (full-circuit analysis and simulation tool) by setting controllable parameters the same as in the experiment. Preliminary full circuit simulation results for electromagnetic pulse transmission to the load are presented. Although divergences exist between calculated and experimentally obtained waveforms before the vacuum section, consistency with load current is satisfactory, especially at the rising edge.

  19. Simultaneous backward data transmission and power harvesting in an ultrasonic transcutaneous energy transfer link employing acoustically dependent electric impedance modulation.

    PubMed

    Ozeri, Shaul; Shmilovitz, Doron

    2014-09-01

    The advancement and miniaturization of body implanted medical devices pose several challenges to Ultrasonic Transcutaneous Energy Transfer (UTET), such as the need to reduce the size of the piezoelectric resonator, and the need to maximize the UTET link power-transfer efficiency. Accordingly, the same piezoelectric resonator that is used for energy harvesting at the body implant, may also be used for ultrasonic backward data transfer, for instance, through impedance modulation. This paper presents physical considerations and design guidelines of the body implanted transducer of a UTET link with impedance modulation for a backward data transfer. The acoustic matching design procedure was based on the 2×2 transfer matrix chain analysis, in addition to the Krimholtz Leedom and Matthaei KLM transmission line model. The UTET power transfer was carried out at a frequency of 765 kHz, continuous wave (CW) mode. The backward data transfer was attained by inserting a 9% load resistance variation around its matched value (550 Ohm), resulting in a 12% increase in the acoustic reflection coefficient. A backward data transmission rate of 1200 bits/s was experimentally demonstrated using amplitude shift keying, simultaneously with an acoustic power transfer of 20 mW to the implant. PMID:24861424

  20. Potential of ultrasonic pulse velocity for evaluating the dimensional stability of oak and chestnut wood.

    PubMed

    Dündar, Türker; Wang, Xiping; As, Nusret; Avcı, Erkan

    2016-03-01

    The objective of this study was to examine the potential of ultrasonic velocity as a rapid and nondestructive method to predict the dimensional stability of oak (Quercus petraea (Mattuschka) Lieblein) and chestnut (Castanea sativa Mill.) that are commonly used in flooring industry. Ultrasonic velocity, specific gravity, and radial, tangential and volumetric shrinkages were measured on seventy-four 20×20×30-mm(3) specimens obtained from freshly cut oak and chestnut stems. The ultrasonic velocities of the specimens decreased with increasing moisture content (MC). We found that specific gravity was not a good predictor of the transverse shrinkages as indicated by relatively weak correlations. Ultrasonic velocity, on the other hand, was found to be a significant predictor of the transverse shrinkages for both oak and chestnut. The best results for prediction of shrinkages of oak and chestnut were obtained when the ultrasonic velocity and specific gravity were used together. The multiple regression models we developed in this study explained 77% of volumetric shrinkages in oak and 72% of volumetric shrinkages in chestnut. It is concluded that ultrasonic velocity coupled with specific gravity can be employed as predicting parameters to evaluate the dimensional stability of oak and chestnut wood during manufacturing process. PMID:26678790

  1. Electrical short pulses generation using a resonant tunneling diode nonlinear transmission line

    NASA Astrophysics Data System (ADS)

    Essimbi, B. Z.; Jäger, D.

    2012-03-01

    In this paper, the generation of short electrical pulses based on nonlinear active wave propagation effects along the resonant tunneling diode transmission line is studied. The principle of operation is discussed and it is shown by computer experiments that an input rectangular pulse as well as a sinusoidal input signal can be converted into a set of output spikes, suitable for A/D conversion at millimeter wave frequencies.

  2. Analysis of Crystallographic Structure of a Japanese Sword by the Pulsed Neutron Transmission Method

    NASA Astrophysics Data System (ADS)

    Kino, K.; Ayukawa, N.; Kiyanagi, Y.; Uchida, T.; Uno, S.; Grazzi, F.; Scherillo, A.

    We measured two-dimensional transmission spectra of pulsed neutron beams for a Japanese sword sample. Atom density, crystalline size, and preferred orientation of crystals were obtained using the RITS code. The position dependence of the atomic density is consistent with the shape of the sample. The crystalline size is very small and shows position dependence, which is understood by the unique structure of Japanese swords. The preferred orientation has strong position dependence. Our study shows the usefulness of the pulsed neutron transmission method for cultural metal artifacts.

  3. Pulse-echo phased array ultrasonic inspection of pultruded rod stitched efficient unitized structure (PRSEUS)

    SciTech Connect

    Johnston, P. H.

    2011-06-23

    A PRSEUS test article was subjected to controlled impact on the skin face followed by static and cyclic axial compressions. Phased array ultrasonic inspection was conducted before impact, and after each of the test conditions. A linear phased array probe with a manual X-Y scanner was used for interrogation. Ultrasound showed a delamination between the skin and stringer flange adjacent to the impact. As designed, the stitching in the flange arrested the lateral flaw formation. Subsequent ultrasonic data showed no delamination growth due to continued loading.

  4. Ultrasonic pulser-receiver

    SciTech Connect

    Taylor, Steven C.

    2006-09-12

    Ultrasonic pulser-receiver circuitry, for use with an ultrasonic transducer, the circuitry comprising a circuit board; ultrasonic pulser circuitry supported by the circuit board and configured to be coupled to an ultrasonic transducer and to cause the ultrasonic transducer to emit an ultrasonic output pulse; receiver circuitry supported by the circuit board, coupled to the pulser circuitry, including protection circuitry configured to protect against the ultrasonic pulse and including amplifier circuitry configured to amplify an echo, received back by the transducer, of the output pulse; and a connector configured to couple the ultrasonic transducer directly to the circuit board, to the pulser circuitry and receiver circuitry, wherein impedance mismatches that would result if the transducer was coupled to the circuit board via a cable can be avoided.

  5. Fundamental aspects of pulse phase-locked loop technology-based methods for measurement of ultrasonic velocity

    NASA Technical Reports Server (NTRS)

    Yost, William T.; Cantrell, John H.; Kushnick, Peter W.

    1992-01-01

    A new instrument based on a constant frequency pulse phase-locked loop concept has been developed to accurately measure the ultrasonic phase velocity in condensed matter. Measurements of the sound velocity in ultrapure water are reported in which both damped and undamped transducers are used with the instrument together with reflectors of various thicknesses placed in the sound propagation path. An analysis of measurements made with the new instrument and similar measurements, taken under identical experimental conditions, using a popular variable frequency pulsed-phase-locked loop instrument is reported. Uncertainties in both measurement systems are analyzed and discussed. A method for measuring inherent phase shifts, not addressed by previous investigations, within the variable frequency pulsed phase-locked loop system and a derivation of the equations that govern the overall use of variable frequency systems using phase-sensitive comparisons are presented. The effects of a finite pulse length on the measurements of phase velocity in dispersive media are addressed in detail.

  6. Fundamental aspects of pulse phase-locked loop technology-based methods for measurement of ultrasonic velocity

    SciTech Connect

    Yost, William T; Cantrell, John H; Kushnick, Peter W

    1992-03-01

    A new instrument based on a constant frequency pulse phase-locked loop concept has been developed to accurately measure the ultrasonic phase velocity in condensed matter. Measurements of the sound velocity in ultrapure water are reported in which both damped and undamped transducers are used with the instrument together with reflectors of various thicknesses placed in the sound propagation path. An analysis of measurements made with the new instrument and similar measurements, taken under identical experimental conditions, using a popular variable frequency pulsed-phase-locked loop instrument is reported. Uncertainties in both measurement systems are analyzed and discussed. A method for measuring inherent phase shifts, not addressed by previous investigators, within the variable frequency pulsed phase-locked loop system and a derivation of the equations that govern the overall use of variable frequency systems using phase-sensitive comparisons are presented. The effects of a finite pulse length on the measurements of phase velocity in dispersive media are addressed in detail.

  7. Regional spectroscopy of paraffin-embedded breast cancer tissue using pulsed terahertz transmission imaging

    NASA Astrophysics Data System (ADS)

    Bowman, Tyler; El-Shenawee, Magda; Campbell, Lucas

    2016-03-01

    This work seeks to obtain the properties of paraffin-embedded breast cancer tumor tissues using transmission imaging and spectroscopy. Formalin-fixed and paraffin-embedded breast tumors are first sectioned into slices of 20 μm and 30 μm and placed between two tsurupica slides. The slides are then scanned in a pulsed terahertz system using transmission imaging. The tissue regions in adjacent pathology section are compared to the transmission imaging scan in order to define a region of points over which to average the electrical properties results from the scan.

  8. Transmission Conditions of Vibration Stresses to Welding Specimens of Ultrasonic Plastic Welding using Various Two-Vibration-System Equipments

    NASA Astrophysics Data System (ADS)

    Tsujino, Jiromaru; Uchida, Takako; Ohkusa, Kunifumi; Adachi, Tatsuya; Ueoka, Tetsugi

    1998-05-01

    Ultrasonic plastic welding is applied for welding various thermoplastic materials and is widely used in various industrial fields. The two-vibration-system welding method and a high frequency equipment are effective in improving the welding characteristics. A high frequency 90 kHz system can weld plastic sheets under a 1/3 velocity amplitude as compared with that of a low 27 kHz system, but it is difficult to weld large specimens successfully because a high frequency vibration stress cannot be transmitted uniformly due to the stress relaxation effect by the small vibration displacement. To improve the direct welding characteristics, three types of two-vibration-system ultrasonic welding equipments using linear vibration loci of (1) 90 kHz and 27 kHz longitudinal vibration systems, (2) 90 kHz longitudinal and 20 kHz torsional vibration systems, and elliptical vibration loci of (3) 27 kHz complex vibration systems are studied. Transmission conditions of the vibration stresses are measured by pressure sensitive films (Prescale) which are inserted between the plastic sheets. It was shown that a high frequency vibration stress with a small displacement amplitude may be induced uniformly in the welding specimens by combining a low frequency vibration with large displacement amplitude. These welding systems are effectively used to join plastic sheets successfully.

  9. Artifact reduction in non-destructive testing by means of complementary data fusion of x-ray computed tomography and ultrasonic pulse-echo testing

    NASA Astrophysics Data System (ADS)

    Schrapp, Michael; Scharrer, Thomas; Goldammer, Matthias; Rupitsch, Stefan J.; Sutor, Alexander; Ermert, Helmut; Lerch, Reinhard

    2013-12-01

    In industrial non-destructive testing, x-ray computed tomography (CT) and ultrasonic pulse-echo testing play an important role in the investigation of large-scale samples. One major artifact arises in CT, when the x-ray absorption in specific directions is too intense, so that the material cannot be fully penetrated. Due to different physical interaction principles, ultrasonic imaging is able to show features which are not visible in the CT image. In this contribution, we present a novel fusion method for the complementary data provided by x-ray CT and ultrasonic testing. The ultrasonic data are obtained by an adapted synthetic aperture focusing technique (SAFT) and complement the missing edge information in the CT image. Subsequently, the full edge map is incorporated as a priori information in a modified simultaneous iterative reconstruction method (SIRT) and allows a significant reduction of artifacts in the CT image.

  10. Traveling-wave pulse on a superconductive active transmission line using resonant tunneling diodes

    NASA Astrophysics Data System (ADS)

    Klofaï, Yerima; Essimbi, B. Z.; Jäger, D.

    2013-10-01

    Analytic study and computer experiment investigations on a superconductive active transmission line using resonant tunneling diodes (RTDs) are discussed. It is shown, based on nonlinear wave propagation effects, that the line supports pulse propagation appearing as pairs of kink-antikink profiles. This behavior is due to compensation between the effects of amplification and dissipation along the network.

  11. A low-power high-speed ultra-wideband pulse radio transmission system.

    PubMed

    Wei Tang; Culurciello, E

    2009-10-01

    We present a low-power high-speed ultra-wideband (UWB) transmitter with a wireless transmission test platform. The system is specifically designed for low-power high-speed wireless implantable biosensors. The integrated transmitter consists of a compact pulse generator and a modulator. The circuit is fabricated in the 0.5-mum silicon-on-sapphire process and occupies 420 mum times 420 mum silicon area. The transmitter is capable of generating pulses with 1-ns width and the pulse rate can be controlled between 90 MHz and 270 MHz. We built a demonstration/testing system for the transmitter. The transmitter achieves a 14-Mb/s data rate. With 50% duty cycle data, the power consumption of the chip is between 10 mW and 21 mW when the transmission distance is from 3.2 to 4 m. The core circuit size is 70 mum times 130 mum. PMID:23853267

  12. Ultrasonic pulse velocity for the evaluation of physical and mechanical properties of a highly porous building limestone.

    PubMed

    Vasanelli, Emilia; Colangiuli, Donato; Calia, Angela; Sileo, Maria; Aiello, Maria Antonietta

    2015-07-01

    UPV as non-destructive technique can effectively contribute to the low invasive in situ analysis and diagnosis of masonry elements related to the conservation, rehabilitation and strengthening of the built heritage. The use of non-destructive and non-invasive techniques brings all the times many advantages in diagnostic activities on pre-existing buildings in terms of sustainability; moreover, it is a strong necessity with respect to the conservation constraints when dealing with the historical-architectural heritage. In this work laboratory experiments were carried out to investigate the effectiveness of ultrasonic pulse velocity (UPV) in evaluating physical and mechanical properties of Lecce stone, a soft and porous building limestone. UPV and selected physical-mechanical parameters such as density and uniaxial compressive strength (UCS) were determined. Factors such as anisotropy and water presence that induce variations on the ultrasonic velocity were also assessed. Correlations between the analysed parameters are presented and discussed. The presence of water greatly affected the values of the analysed parameters, leading to a decrease of UPV and to a strong reduction of the compressive strength. A discussion of the role of the water on these results is provided. Regression analysis showed a reliable linear correlation between UPV and compressive strength, which allows a reasonable estimation of the strength of Lecce stone by means of non-destructive testing methods such as the ultrasonic wave velocity. Low correlation between UPV and density was found, suggesting that other factors than density, related to the fabric and composition, also influence the response of the selected stone to the UPV. They have no influence on the UCS, that instead showed to be highly correlated with the packing density. PMID:25769219

  13. Ultrasonic damage detection of concrete structures by using pulse-echo sensor arrays and SAFT

    NASA Astrophysics Data System (ADS)

    Shi, Li-hua; Shao, Zhi-xue; Shao, Zhe

    2009-07-01

    In ultrasonic nondestructive testing (NDT) of concrete structures, the synthetic aperture focusing technique (SAFT) can improve the resolution of target and therefore gives a better image display of the B-scan data. In traditional B-scan of concrete structures the ultrasonic transducers are usually moved manually to detect the whole structure, the detection speed and the consistency in different test points are greatly affected. A PZT sensor array is designed in this paper to perform B-scan on large concrete structures more efficiently. The excitation of the sensor array and the data processing techniques for the array data are discussed. A signal processing approach is proposed to improve the consistency between different test channels in the array. Experiments on real structures show the embedded objects can be located accurately by using the array sensor and SAFT method.

  14. Wind turbines and bat mortality: Doppler shift profiles and ultrasonic bat-like pulse reflection from moving turbine blades.

    PubMed

    Long, Chloe V; Flint, James A; Lepper, Paul A

    2010-10-01

    Bat mortality resulting from actual or near-collision with operational wind turbine rotors is a phenomenon that is widespread but not well understood. Because bats rely on information contained in high-frequency echoes to determine the nature and movement of a target, it is important to consider how ultrasonic pulses similar to those used by bats for echolocation may be interacting with operational turbine rotor blades. By assessing the characteristics of reflected ultrasonic echoes, moving turbine blades operating under low wind speed conditions (<6 m s(-1)) were found to produce distinct Doppler shift profiles at different angles to the rotor. Frequency shifts of up to ±700-800 Hz were produced, which may not be perceptible by some bat species. Monte Carlo simulation of bat-like sampling by echolocation revealed that over 50 rotor echoes could be required by species such as Pipistrellus pipistrellus for accurate interpretation of blade movement, which may not be achieved in the bat's approach time-window. In summary, it was found that echoes returned from moving blades had features which could render them attractive to bats or which might make it difficult for the bat to accurately detect and locate blades in sufficient time to avoid a collision. PMID:20968394

  15. Nonlinear ultrasonic pulsed measurements and applications to metal processing and fatigue

    NASA Astrophysics Data System (ADS)

    Yost, William T.; Cantrell, John H.; Na, Jeong K.

    2001-04-01

    Nonlinear ultrasonics research at NASA-Langley Research Center emphasizes development of experimental techniques and modeling, with applications to metal fatigue and metals processing. This review work includes a summary of results from our recent efforts in technique refinement, modeling of fatigue related microstructure contributions, and measurements on fatigued turbine blades. Also presented are data on 17-4PH and 410-Cb stainless steels. The results are in good agreement with the models.

  16. DONAR - A computer processing system to extend ultrasonic pulse-echo testing.

    NASA Technical Reports Server (NTRS)

    Lees, S.; Gerhard, F. B.; Barber, F. E.; Cheney, S. P.

    1973-01-01

    A dedicated general purpose digital computer has been built on the principle of a sampled-data system to run an ultrasonic subsystem under programmed control. A most significant application is the ability to extract a signal from an interfering background. As illustrated in the paper, a 1 mm diameter transducer was used to measure the diameter of a 2.5 mm OD plastics tube with 0.4 mm wall thickness. Echoes from all four surfaces were displayed and the measurements indicated an uncertainty of less than 0.1 mm.

  17. Properties of defect-induced multiple pulse laser damage of transmission components.

    PubMed

    Ma, Bin; Zhang, Li; Lu, Menglei; Wang, Ke; Jiao, Hongfei; Zhang, Jinlong; Cheng, Xinbin; Yang, Liming; Wang, Zhanshan

    2016-09-01

    When the number of laser pulses increases, the laser-induced damage threshold of the optical components gradually declines. The magnitude and tendency of this reduced threshold are associated with various factors. Furthermore, this reduced threshold is conclusively determined by the limiting factors or defect characteristics that trigger damage to optical components. Then, fully understanding the damage properties of different kinds of defects will contribute to the optimization of the performance and lifetime of the optical components. In this study, the statistical and deterministic characterizations of the fatigue effect are used to evaluate the properties of the multiple pulse laser damage of transmission components. First, the influence of spot sizes and polishing materials on the properties of the multiple pulse laser damage of optical components is discussed. Then, the structural, absorptive, and mixed artificial defects are fabricated, and the damage characteristics are evaluated and analyzed. Finally, the damage mechanism of different factors has been clarified. PMID:27607284

  18. A long-pulse repetitive operation magnetically insulated transmission line oscillator.

    PubMed

    Fan, Yu-Wei; Zhong, Hui-Huang; Zhang, Jian-De; Shu, Ting; Liu, Jin Liang

    2014-05-01

    The improved magnetically insulated transmission line oscillator (MILO) is a gigawatt-class L-band high power microwave tube. It has allowed us to generate 3.1 GW pulse of 40 ns duration in the single-pulse operation and 500 MW pulse of 25 ns duration in the repetition rate operation. However, because of the severe impedance mismatch, the power conversion efficiency is only about 4% in the repetition rate operation. In order to eliminate the impedance mismatch and obtain repetitive long-pulse high-power microwave (HPM), a series of experiments are carried out and the recent progress is presented in this paper. In the single-pulse operation, when the diode voltage is 466 kV and current is 41.6 kA, the radiated microwave power is above 2.2 GW, the pulse duration is above 102 ns, the microwave frequency is about 1.74 GHz, and the power conversion efficiency is about 11.5%. In the repetition rate operation, under the condition of the diode voltage about 400 kV, beam current about 38 kA, the radiated microwave power is about 1.0 GW, the pulse duration is about 85 ns. Moreover, the radiated microwave power and the pulse duration decline little by little when the shot numbers increase gradually. The experimental results show that the impedance matching is a vital factor for HPM systems and one of the major technical challenges is to improve the cathode for the repetition rate operation MILO. PMID:24880374

  19. A long-pulse repetitive operation magnetically insulated transmission line oscillator

    SciTech Connect

    Fan, Yu-Wei; Zhong, Hui-Huang; Zhang, Jian-De; Shu, Ting; Liu, Jin Liang

    2014-05-15

    The improved magnetically insulated transmission line oscillator (MILO) is a gigawatt-class L-band high power microwave tube. It has allowed us to generate 3.1 GW pulse of 40 ns duration in the single-pulse operation and 500 MW pulse of 25 ns duration in the repetition rate operation. However, because of the severe impedance mismatch, the power conversion efficiency is only about 4% in the repetition rate operation. In order to eliminate the impedance mismatch and obtain repetitive long-pulse high-power microwave (HPM), a series of experiments are carried out and the recent progress is presented in this paper. In the single-pulse operation, when the diode voltage is 466 kV and current is 41.6 kA, the radiated microwave power is above 2.2 GW, the pulse duration is above 102 ns, the microwave frequency is about 1.74 GHz, and the power conversion efficiency is about 11.5%. In the repetition rate operation, under the condition of the diode voltage about 400 kV, beam current about 38 kA, the radiated microwave power is about 1.0 GW, the pulse duration is about 85 ns. Moreover, the radiated microwave power and the pulse duration decline little by little when the shot numbers increase gradually. The experimental results show that the impedance matching is a vital factor for HPM systems and one of the major technical challenges is to improve the cathode for the repetition rate operation MILO.

  20. In-situ application of Ultrasonic Pulse Velocity measurements to determine the degree of zeolitic alteration of ignimbrites

    NASA Astrophysics Data System (ADS)

    Evren Çubukçu, H.; Yurdakul, Yasin; Erkut, Volkan; Akkaş, Efe; Akın, Lütfiye; Ulusoy, İnan; Şen, Erdal

    2016-04-01

    The velocity of P-waves passing through a rock body is strongly dependent on the petrographical properties such as texture, crystallinity, porosity and fracture network. For this reason, the measurement of ultrasonic pulse velocities (UPV) has been widely used in various applications interested in mechanical properties of solid rock bodies. An ignimbrite is a deposit of pyroclastic density current originating from an explosive volcanic eruption and comprises of vitric volcanic ash, free crystals, juvenile magma fragments (pumice) and accidental xenoliths. The complex nature of the componentry of ignimbrites also exhibits spatial variation depending on the location of deposition. Furthermore, both syn- and post-depositional processes (i.e. welding, alteration etc.) may have drastic impact on the mechanical characteristics of the ignimbrites. Alteration can be defined as the devitrification and the crystallization of vitric components and the transformation of pre-existing minerals of the ignimbrite into new minerals under changing thermodynamic conditions. In this context, zeolitization is an alteration process in which metastable (vitric) components of an ignimbrite body are replaced by zeolite group of minerals under low temperature and pressure induced by hydrothermal activity. The crystallization of zeolite minerals in the pore space promotes an increase in crystallinity and therefore a decrease in porosity. Hence, the velocity of P-waves passing through a zeolitized ignimbrite will be considerably higher compared to those in unaltered counterparts. Within the scope of a TUBİTAK project (No:113Y439) in which the alteration properties of Cappadocian Ignimbrites (Nevşehir, Turkey) are being investigated, in-situ UPV measurements have been performed using a portable pulse test instrument. The acquired velocity data has been correlated with the modal proportions of secondary zeolite minerals obtained by SEM-EDS. The results demonstrate that the measured P

  1. Investigations on optimizing the energy transmission of ultrafast optical pulses in pure water

    NASA Astrophysics Data System (ADS)

    Lukofsky, David

    Many of today's communication and imaging technologies share the common challenge of signal deterioration due to water's large absorption coefficient. As an example, it is water molecules that contaminate the fused silica of optical fibers and account for most of the absorption they exhibit at communication wavelengths. It is also water (in the form of vapor) that makes it challenging to devise practical THz spectroscopic systems. As such, this thesis examines how the transmission of electromagnetic radiation through water could be improved as a stepping stone towards bettering a wide array of communication and imaging applications. Recent time-domain approaches have noted the connection between pulse rise-time and precursor waveform absorption. This thesis represents the first in-depth analysis of precursors using an intuitive frequency-domain approach. It was shown with well-known physical metrics that precursors are a linear effect resulting from the temporal representation of a Beer's law of absorption for broadband pulses. Experimental validation was achieved with a spatial light modulator used in conjunction with Frequency-Resolved-Optical-Gating (FROG) to obtain the first measurement of the amplitude and phase of an optical precursor. The semi-classical two-level atom model was used to infer the transitional dipole moments of the 1447 nm and 2:94 mum vibrational resonances of the medium. These values supported finite-difference-time-domain simulations suggesting how 52 fs sech2 pulses of 220 GW/cm2 peak intensity could propagate with negligible attenuation over 15 absorption lengths when tuned to the 2:94 mum transition of water. Extensive use of 1550 nm lasers in communication systems and the presence of the second vibrational overtone resonance of water at 1447 nm were the motivation for transmission experiments completed at the Naval Research Laboratory (Washington, DC) at this transition. As much as a 500% increase in absolute transmission was observed

  2. Adaptive filtering for reduction of speckle in ultrasonic pulse-echo images.

    PubMed

    Bamber, J C; Daft, C

    1986-01-01

    Current medical ultrasonic scanning instrumentation permits the display of fine image detail (speckle) which does not transfer useful information but degrades the apparent low contrast resolution in the image. An adaptive two-dimensional filter has been developed which uses local features of image texture to recognize and maximally low-pass filter those parts of the image which correspond to fully developed speckle, while substantially preserving information associated with resolved-object structure. A first implementation of the filter is described which uses the ratio of the local variance and the local mean as the speckle recognition feature. Preliminary results of applying this form of display processing to medical ultrasound images are very encouraging; it appears that the visual perception of features such as small discrete structures, subtle fluctuations in mean echo level and changes in image texture may be enhanced relative to that for unprocessed images. PMID:3510500

  3. Mid IR pulsed light source for laser ultrasonic testing of carbon-fiber-reinforced plastic

    NASA Astrophysics Data System (ADS)

    Hatano, H.; Watanabe, M.; Kitamura, K.; Naito, M.; Yamawaki, H.; Slater, R.

    2015-09-01

    A quasi-phase-matched (QPM) optical parametric oscillator (OPO) was developed using a periodically poled Mg-doped stoichiometric LiTaO3 crystal to generate mid-IR light for excitation of laser ultrasound in carbon fiber reinforced plastic (CFRP). The ultrasound generation efficiency was measured at the three different wavelengths that emanate from the OPO: 1.064 μm, 1.59/1.57 μm, and 3.23/3.30 μm. The measurements indicate that mid-IR 3.2-3.3 μm light generates the most efficient ultrasonic waves in CFRP with the least laser damage. We used mid-IR light in conjunction with a laser interferometer to demonstrate the detection of flaws/defects in CFRP such as the existence of air gaps that mimic delamination and voids in CFRP, and the inhomogeneous adhesion of CFRP material to a metal plate was also clearly detected.

  4. Histotripsy Produced by Hundred-Microsecond-Long Focused Ultrasonic Pulses: A Preliminary Study.

    PubMed

    Guan, Yubo; Lu, Mingzhu; Li, Yujiao; Liu, Fenfen; Gao, Ya; Dong, Tengju; Wan, Mingxi

    2016-09-01

    A new strategy is proposed in this study to rapidly generate mechanical homogenized lesions using hundred-microsecond-long pulses. The pulsing scheme was divided into two stages: generating sufficient bubble seed nuclei via acceleration by boiling bubbles and efficiently forming a mechanically homogenized and regularly shaped lesion with a homogenate inside via inertial cavitation. The duty cycle was set at 4.9%/3.9% in stage 1 and 1%/0.88% in stage 2 by changing the pulse duration (PD) and off-time independently. The pulse sequence was 500-μs/400-μs PD with a 100-Hz pulse repetition frequency (PRF) in stage 1, followed by 500-μs/400-μs PD with a 100-Hz PRF and 200-μs PD with a 200-Hz PRF in stage 2. Experiments were conducted on polyacrylamide phantoms with bovine serum albumin and on ex vivo porcine kidney tissues using a single-element 1.06-MHz transducer at an 8-MPa peak negative pressure with shock waves. The lesion evolution and dynamic elastic modulus variation in the phantoms and the histology in the tissue samples were investigated. The results indicate that the two-stage treatment using hundred-microsecond-long pulses can efficiently produce mechanically homogenized lesions with smooth borders, long tear shapes and the total homogenate inside. The time to generate a single mechanically homogenized lesion is shortened from >50 s to 17.1 s. PMID:27318864

  5. Non-invasive Measurement of Thermal Diffusivity Using High-Intensity Focused Ultrasound and Through-Transmission Ultrasonic Imaging.

    PubMed

    Yeshurun, Lilach; Azhari, Haim

    2016-01-01

    Thermal diffusivity at the site ablated by high-intensity focused ultrasound (HIFU) plays an important role in the final therapeutic outcome, as it influences the temperature's spatial and temporal distribution. Moreover, as tissue thermal diffusivity is different in tumors as compared with normal tissue, it could also potentially be used as a new source of imaging contrast. The aim of this study was to examine the feasibility of combining through-transmission ultrasonic imaging and HIFU to estimate thermal diffusivity non-invasively. The concept was initially evaluated using a computer simulation. Then it was experimentally tested on phantoms made of agar and ex vivo porcine fat. A computerized imaging system combined with a HIFU system was used to heat the phantoms to temperatures below 42°C to avoid irreversible damage. Through-transmission scanning provided the time-of-flight values in a region of interest during its cooling process. The time-of-flight values were consequently converted into mean values of speed of sound. Using the speed-of-sound profiles along with the developed model, we estimated the changes in temperature profiles over time. These changes in temperature profiles were then used to calculate the corresponding thermal diffusivity of the studied specimen. Thermal diffusivity for porcine fat was found to be lower by one order of magnitude than that obtained for agar (0.313×10(-7)m(2)/s vs. 4.83×10(-7)m(2)/s, respectively, p < 0.041). The fact that there is a substantial difference between agar and fat implies that non-invasive all-ultrasound thermal diffusivity mapping is feasible. The suggested method may particularly be suitable for breast scanning. PMID:26489364

  6. Lumped-element model of a tapered transmission line for impedance matching in a pulsed power system

    NASA Astrophysics Data System (ADS)

    Lee, Kun-A.; Ko, Kwang-Cheol

    2016-07-01

    In a pulsed power system, impedance matching is one of the significant factors for increasing the efficiency of the system. One of the most general methods for impedance matching is to use a tapered transmission line. Because the characteristics of a tapered transmission line are changed continuously according to its position, modeling the tapered transmission line by using lumped elements is difficult. In this study, we investigated a tapered transmission line to match the impedance of power supply to that of a load by using lumped elements especially in a pulsed power system. In modeling the tapered transmission line, we used the concept of a transmission, and we introduced an efficient modeling method. We propose a simulation model based on the investigation results. The results of the study will be useful for research on tapered transmission lines.

  7. Transmission line pulse system for avalanche characterization of high power semiconductor devices

    NASA Astrophysics Data System (ADS)

    Riccio, Michele; Ascione, Giovanni; De Falco, Giuseppe; Maresca, Luca; De Laurentis, Martina; Irace, Andrea; Breglio, Giovanni

    2013-05-01

    Because of the increasing in power density of electronic devices for medium and high power application, reliabilty of these devices is of great interest. Understanding the avalanche behaviour of a power device has become very important in these last years because it gives an indication of the maximum energy ratings which can be seen as an index of the device ruggedness. A good description of this behaviour is given by the static IV blocking characteristc. In order to avoid self heating, very relevant in high power devices, very short pulses of current have to be used, whose value can change from few milliamps up to tens of amps. The most used method to generate short pulses is the TLP (Transmission Line Pulse) test, which is based on charging the equivalent capacitance of a transmission line to high value of voltage and subsequently discharging it onto a load. This circuit let to obtain very short square pulses but it is mostly used for evaluate the ESD capability of semiconductor and, in this environment, it generates pulses of low amplitude which are not high enough to characterize the avalanche behaviour of high power devices . Advanced TLP circuit able to generate high current are usually very expensive and often suffer of distorption of the output pulse. In this article is proposed a simple, low cost circuit, based on a boosted-TLP configuration, which is capable to produce very square pulses of about one hundreds of nanosecond with amplitude up to some tens of amps. A prototype is implemented which can produce pulses up to 20A of amplitude with 200 ns of duration which can characterize power devices up to 1600V of breakdown voltage. Usage of microcontroller based logic make the circuit very flexible. Results of SPICE simulation are provided, together with experimental results. To prove the effectiveness of the circuit, the I-V blocking characteristics of two commercial devices, namely a 600V PowerMOS and a 1200V Trench-IGBT, are measured at different

  8. All-fiber-integrated linearly polarized fiber laser delivering 476  μJ, 50  kHz, nanosecond pulses for ultrasonic generation.

    PubMed

    Zhang, Pengfei; Xu, Xiaodong; Yu, Hailong; Su, Rongtao; Wang, Xiaolin; Yang, Lijia

    2016-05-10

    We demonstrate a high-energy linearly polarized pulsed fiber laser for ultrasonic generation based on a master oscillator power amplification (MOPA) scheme, which delivers nanosecond pulses with duration of 4.8 ns and pulse energy of 476 μJ at the repetition rate of 50 kHz. The MOPA is seeded by a gain switch semiconductor laser diode at 1064 nm. In the pre-amplification stages, a double-pass amplification structure is designed and successfully applied to amplify the low-power seed laser for the consideration of suppressing amplified spontaneous emission, decreasing the number of amplification stages, and reducing the nonlinear effects. A highly ytterbium-doped fiber is utilized in the main amplifier to shorten the fiber length and reduce the fiber nonlinearity. The average power is finally boosted to 23.8 W with corresponding optical-to-optical efficiency of 66.9% and a polarization extinction rate of ∼10.5  dB. The corresponding peak power is calculated to be 87.1 kW. Finally, the established laser system is successfully used for ultrasonic generation based on a line excitation configuration and grating excitation configuration, and clear surface acoustic wave signals are detected. Many potential applications in laser ultrasonics can be foreseen. PMID:27168281

  9. The effect of stress on ultrasonic pulses in fiber reinforced composites

    NASA Technical Reports Server (NTRS)

    Hemann, J. H.; Baaklini, G. Y.

    1983-01-01

    An acoustical-ultrasonic technique was used to demonstrate relationships existing between changes in attenuation of stress waves and tensile stress for an eight ply 0 degree graphite-epoxy fiber reinforced composite. All tests were conducted in the linear range of the material for which no mechanical or macroscopic damage was evident. Changes in attenuation were measured as a function of tensile stress in the frequency domain and in the time domain. Stress wave propagation in these specimens was dispersive, i.e., the wave speed depends on frequency. Wave speeds varied from 267 400 cm/sec to 680 000 cm/sec as the frequency of the signal was varied from 150 kHz to 1.9 MHz which strongly suggests that flexural/lamb wave modes of propagation exist. The magnitude of the attenuation changes depended strongly on tensile stress. It was further observed that the wave speeds increased slightly for all tested frequencies as the stress was increased.

  10. Simple Laser-Ultrasonic System Using a Single-Frequency Pulsed Laser Oscillator

    NASA Astrophysics Data System (ADS)

    Blouin, A.; Carrion, L.; Padioleau, C.; Bouchard, P.; Monchalin, J.-P.

    2005-04-01

    We present a new pulsed laser oscillator and system for the optical detection of ultrasound in materials using a flashlamp-pumped dual Nd:YAG rod configuration. A single-frequency laser oscillator based on one rod inside a ring cavity is proposed. The second rod can be used as an amplifier for the oscillator or as a generation laser. Performance of the system is investigated with a two-wave mixing phase demodulator. Tests on metallic samples are presented.

  11. Ultrasonic Inspection Of Thick Sections

    NASA Technical Reports Server (NTRS)

    Friant, C. L.; Djordjevic, B. B.; O'Keefe, C. V.; Ferrell, W.; Klutz, T.

    1993-01-01

    Ultrasonics used to inspect large, relatively thick vessels for hidden defects. Report based on experiments in through-the-thickness transmission of ultrasonic waves in both steel and filament-wound composite cases of solid-fuel rocket motors.

  12. Modeling the Effects of Beam Size and Flaw Morphology on Ultrasonic Pulse/Echo Sizing of Delaminations in Carbon Composites

    NASA Technical Reports Server (NTRS)

    Margetan, Frank J.; Leckey, Cara A.; Barnard, Dan

    2012-01-01

    The size and shape of a delamination in a multi-layered structure can be estimated in various ways from an ultrasonic pulse/echo image. For example the -6dB contours of measured response provide one simple estimate of the boundary. More sophisticated approaches can be imagined where one adjusts the proposed boundary to bring measured and predicted UT images into optimal agreement. Such approaches require suitable models of the inspection process. In this paper we explore issues pertaining to model-based size estimation for delaminations in carbon fiber reinforced laminates. In particular we consider the influence on sizing when the delamination is non-planar or partially transmitting in certain regions. Two models for predicting broadband sonic time-domain responses are considered: (1) a fast "simple" model using paraxial beam expansions and Kirchhoff and phase-screen approximations; and (2) the more exact (but computationally intensive) 3D elastodynamic finite integration technique (EFIT). Model-to-model and model-to experiment comparisons are made for delaminations in uniaxial composite plates, and the simple model is then used to critique the -6dB rule for delamination sizing.

  13. The combined use of heat-pulse flowmeter logging and packer testing for transmissive fracture recognition

    NASA Astrophysics Data System (ADS)

    Lo, Hung-Chieh; Chen, Po-Jui; Chou, Po-Yi; Hsu, Shih-Meng

    2014-06-01

    This paper presents an improved borehole prospecting methodology based on a combination of techniques in the hydrogeological characterization of fractured rock aquifers. The approach is demonstrated by on-site tests carried out in the Hoshe Experimental Forest site and the Tailuge National Park, Taiwan. Borehole televiewer logs are used to obtain fracture location and distribution along boreholes. The heat-pulse flow meter log is used to measure vertical velocity flow profiles which can be analyzed to estimate fracture transmissivity and to indicate hydraulic connectivity between fractures. Double-packer hydraulic tests are performed to determine the rock mass transmissivity. The computer program FLASH is used to analyze the data from the flowmeter logs. The FLASH program is confirmed as a useful tool which quantitatively predicts the fracture transmissivity in comparison to the hydraulic properties obtained from packer tests. The location of conductive fractures and their transmissivity is identified, after which the preferential flow paths through the fracture network are precisely delineated from a cross-borehole test. The results provide robust confirmation of the use of combined flowmeter and packer methods in the characterization of fractured-rock aquifers, particularly in reference to the investigation of groundwater resource and contaminant transport dynamics.

  14. The Next Linear Collider Test Accelerator's RF Pulse Compression And Transmission

    SciTech Connect

    Tantawi, S.G.; Adelphson, C.; Holmes, S.; Lavine, Theodore L.; Loewen, R.J.; Nantista, C.; Pearson, C.; Pope, R.; Rifkin, J.; Ruth, R.D.; Vlieks, A.E.; /SLAC

    2011-09-14

    The overmoded rf transmission and pulsed power compression system for SLAC's Next Linear Collider (NLC) program requires a high degree of transmission efficiency and mode purity to be economically feasible. To this end, a number of new, high power components and systems have been developed at X-band, which transmit rf power in the low loss, circular TE01 mode with negligible mode conversion. In addition, a highly efficient SLED-II* pulse compressor has been developed and successfully tested at high power. The system produced a 200 MW, 250 ns wide pulse with a near-perfect flat-top. In this paper we describe the design and test results of the high power pulse compression system using SLED-II. The NLC rf systems use low loss highly over-moded circular waveguides operating in the TE01 mode. The efficiency of the systems is sensitive to the mode purity of the mode excited inside these guides. We used the so called flower petal mode transducer [2] to excite the TE01 mode. This type of mode transducer is efficient, compact and capable of handling high levels of power. To make more efficient systems, we modified this device by adding several mode selective chokes to act as mode purifiers. To manipulate the rf signals we used these modified mode converters to convert back and forth between over-moded circular waveguides and single-moded WR90 rectangular waveguides. Then, we used the relatively simple rectangular waveguide components to do the actual manipulation of rf signals. For example, two mode transducers and a mitered rectangular waveguide bend comprise a 90 degree bend. Also, a magic tee and four mode transducers would comprise a four-port-hybrid, etc. We will discuss the efficiency of an rf transport system based on the above methodology. We also used this methodology in building the SLEDII pulse compression system. At SLAC we built 4 of these pulse systems. In this paper we describe the SLEDII system and compare the performance of these 4 systems at SLAC. We

  15. Beam-forming techniques with applications to pulsed Doppler ultrasonic flowmeters

    NASA Astrophysics Data System (ADS)

    Fu, C. C.

    The near-field and array approaches to beam forming appear to be the most practical and useful methods for providing uniform illumination of the cross section of blood vessels. Through the near-field approach, the required beam patterns are produced in the near field of pulsed transducers and, as a result, it is most suitable for peripheral applications. Field patterns of pulsed transducers are defined and are investigated by theoretical analysis, numerical simulation, and experimental characterization to verify the validity and indicate the limitations of this approach. Transducers are designed and fabricated, based on these results, and are employed in the preliminary flowmeter system evaluation. The use of transducer arrays is the only viable approach to deepbody measurements and flexible beamwidth adjustment. A theory, founded on the finite Fourier-Bessel and Dini series expansions, is developed to synthesize circularly symmetrical beam patterns by means of concentric annular arrays. Its application to the generation of variable-width uniform beams results in a canonical design procedure. A prototype transducer array suitable for transcutaneous cardiac-output estimation was developed.

  16. A novel structure of transmission line pulse transformer with mutually coupled windings.

    PubMed

    Yu, Binxiong; Su, Jiancang; Li, Rui; Zhao, Liang; Zhang, Xibo; Wang, Junjie

    2014-03-01

    A novel structure of transmission line transformer (TLT) with mutually coupled windings is described in this paper. All transmission lines except the first stage of the transformer are wound on a common ferrite core for the TLT with this structure. A referral method was introduced to analyze the TLT with this structure, and an analytic expression of the step response was derived. It is shown that a TLT with this structure has a significantly slower droop rate than a TLT with other winding structures and the number of ferrite cores needed is largely reduced. A four-stage TLT with this structure was developed, whose input and output impedance were 4.2 Ω and 67.7 Ω, respectively. A frequency response test of the TLT was carried out. The test results showed that pulse response time of the TLT is several nanoseconds. The TLT described in this paper has the potential to be used as a rectangle pulse transformer with very fast response time. PMID:24689623

  17. Constant frequency pulsed phase-locked-loop instrument for measurement of ultrasonic velocity

    SciTech Connect

    Yost, William T; Cantrell, John H; Kushnick, Peter W

    1991-10-01

    A new instrument based on a constant frequency pulsed phase-locked-loop (CFPPLL) concept has been developed to accurately measure the ultrasonicwavevelocity in liquids and changes in ultrasonicwavevelocity in solids and liquids. An analysis of the system shows that it is immune to many of the frequency-dependent effects that plague other techniques including the constant phase shifts of reflectors placed in the path of the ultrasonicwave.Measurements of the sound velocity in ultrapure water are used to confirm the analysis. The results are in excellent agreement with values from the literature, and establish that the CFPPLL provides a reliable, accurate way to measurevelocities, as well as for monitoring small changes in velocity without the sensitivity to frequency-dependent phase shifts common to other measurement systems. The estimated sensitivity to phase changes is better than a few parts in 10{sup 7}.

  18. Magnetohydrodynamic electromagnetic pulse (MHD-EMP) interaction with power transmission and distribution systems

    SciTech Connect

    Tesche, F.M.; Barnes, P.R.; Meliopoulos, A.P.S.

    1992-02-01

    This report discusses the effects of the late-time high-altitude electromagnetic pulse (HEMP) on electrical transmission and distribution (T&D) systems. This environment, known as the magnetohydrodynamic electromagnetic pulse (MHD-EMP), is a very slowly varying electric field induced in the earth`s surface, similar to the field induced by a geomagnetic storm. It can result in the flow of a quasi-dc current in grounded power lines and in the subsequent magnetic saturation of transformers. This saturation, in turn, causes 6-Hz harmonic distortion and an increase in the reactive power required by generation facilities. This report analyzes and discusses these phenomena. The MHD-EMP environment is briefly discussed, and a simplified form of the earth-induced electric field is developed for use in a parametric study of transmission line responses. Various field coupling models are described, and calculated results for the responses of both transmission- and distribution-class power lines are presented. These calculated responses are compared with measurements of transformer operation under dc excitation to infer the MHD-EMP response of these power system components. It is found that the MHD-EMP environment would have a marked effect on a power system by inducing up to several hundreds of amperes of quasi-dc current on power lines. These currents will cause transformers to saturate which could result in excessive harmonic generation, voltage swings, and voltage suppression. The design of critical facilities which are required to operate during and after MHD-EMP events will have to be modified in order to mitigate the effects of these abnormal power system conditions.

  19. Magnetohydrodynamic electromagnetic pulse (MHD-EMP) interaction with power transmission and distribution systems

    SciTech Connect

    Tesche, F.M. , Dallas, TX ); Barnes, P.R. ); Meliopoulos, A.P.S. . Dept. of Electrical Engineering)

    1992-02-01

    This report discusses the effects of the late-time high-altitude electromagnetic pulse (HEMP) on electrical transmission and distribution (T D) systems. This environment, known as the magnetohydrodynamic electromagnetic pulse (MHD-EMP), is a very slowly varying electric field induced in the earth's surface, similar to the field induced by a geomagnetic storm. It can result in the flow of a quasi-dc current in grounded power lines and in the subsequent magnetic saturation of transformers. This saturation, in turn, causes 6-Hz harmonic distortion and an increase in the reactive power required by generation facilities. This report analyzes and discusses these phenomena. The MHD-EMP environment is briefly discussed, and a simplified form of the earth-induced electric field is developed for use in a parametric study of transmission line responses. Various field coupling models are described, and calculated results for the responses of both transmission- and distribution-class power lines are presented. These calculated responses are compared with measurements of transformer operation under dc excitation to infer the MHD-EMP response of these power system components. It is found that the MHD-EMP environment would have a marked effect on a power system by inducing up to several hundreds of amperes of quasi-dc current on power lines. These currents will cause transformers to saturate which could result in excessive harmonic generation, voltage swings, and voltage suppression. The design of critical facilities which are required to operate during and after MHD-EMP events will have to be modified in order to mitigate the effects of these abnormal power system conditions.

  20. Losses at magnetic nulls in pulsed-power transmission line systems

    NASA Astrophysics Data System (ADS)

    Mendel, C. W.; Pointon, T. D.; Savage, M. E.; Seidel, D. B.; Magne, I.; Vézinet, R.

    2006-04-01

    Pulsed-power systems operating in the terawatt regime must deal with large electron flows in vacuum transmission lines. In most parts of these transmission lines the electrons are constrained by the self-magnetic field to flow parallel to the conductors. In very low impedance systems, such as those used to drive Z-pinch radiation sources, the currents from multiple transmission lines are added together. This addition necessarily involves magnetic nulls that connect the positive and negative electrodes. The resultant local loss of magnetic insulation results in electron losses at the anode in the vicinity of the nulls. The lost current due to the magnetic null might or might not be appreciable. In some cases the lost current due to the null is not large, but is spatially localized, and may create a gas and plasma release from the anode that can lead to an excessive loss, and possibly to catastrophic damage to the hardware. In this paper we describe an analytic model that uses one geometric parameter (aside from straightforward hardware size measurements) that determines the loss to the anode, and the extent of the loss region when the driving source and load are known. The parameter can be calculated in terms of the magnetic field in the region of the null calculated when no electron flow is present. The model is compared to some experimental data, and to simulations of several different hardware geometries, including some cases with multiple nulls, and unbalanced feeds.

  1. Losses at magnetic nulls in pulsed-power transmission line systems

    SciTech Connect

    Mendel, C.W. Jr.; Pointon, T.D.; Savage, M.E.; Seidel, D.B.; Magne, I.; Vezinet, R.

    2006-04-15

    Pulsed-power systems operating in the terawatt regime must deal with large electron flows in vacuum transmission lines. In most parts of these transmission lines the electrons are constrained by the self-magnetic field to flow parallel to the conductors. In very low impedance systems, such as those used to drive Z-pinch radiation sources, the currents from multiple transmission lines are added together. This addition necessarily involves magnetic nulls that connect the positive and negative electrodes. The resultant local loss of magnetic insulation results in electron losses at the anode in the vicinity of the nulls. The lost current due to the magnetic null might or might not be appreciable. In some cases the lost current due to the null is not large, but is spatially localized, and may create a gas and plasma release from the anode that can lead to an excessive loss, and possibly to catastrophic damage to the hardware. In this paper we describe an analytic model that uses one geometric parameter (aside from straightforward hardware size measurements) that determines the loss to the anode, and the extent of the loss region when the driving source and load are known. The parameter can be calculated in terms of the magnetic field in the region of the null calculated when no electron flow is present. The model is compared to some experimental data, and to simulations of several different hardware geometries, including some cases with multiple nulls, and unbalanced feeds.

  2. Losses at magnetic nulls in pulsed-power transmission line systems.

    SciTech Connect

    Magne, I.; Savage, Mark Edward; Seidel, David Bruce; Mendel, Clifford Will, Jr.; Pointon, Timothy David; Vezinet, R.

    2004-08-01

    Pulsed-power systems operating in the terawatt regime must deal with large electron flows in vacuum transmission lines. In most parts of these transmission lines the electrons are constrained by the self-magnetic field to flow parallel to the conductors. In very low impedance systems, such as those used to drive Z-pinch radiation sources, the currents from multiple transmission lines are added together. This addition necessarily involves magnetic nulls that connect the positive and negative electrodes. The resultant local loss of magnetic insulation results in electron losses at the anode in the vicinity of the nulls. The lost current due to the magnetic null might or might not be appreciable. In some cases the lost current due to the null is not large, but is spatially localized, and may create a gas and plasma release from the anode that can lead to an excessive loss, and possibly to catastrophic damage to the hardware. In this paper we describe an analytic model that uses one geometric parameter (aside from straightforward hardware size measurements) that determines the loss to the anode, and the extent of the loss region when the driving source and load are known. The parameter can be calculated in terms of the magnetic field in the region of the null calculated when no electron flow is present. The model is compared to some experimental data, and to simulations of several different hardware geometries, including some cases with multiple nulls, and unbalanced feeds.

  3. Measurement of internal diameter changes and pulse wave velocity in fetal descending aorta using the ultrasonic phased-tracking method in normal and growth-restricted fetuses.

    PubMed

    Miyashita, Susumu; Murotsuki, Jun; Muromoto, Jin; Ozawa, Katsusuke; Yaegashi, Nobuo; Hasegawa, Hideyuki; Kanai, Hiroshi

    2015-05-01

    Phased tracking (PT) is an ultrasound-based technique that enables precise measurement of a target velocity. The aims of this study were to use PT to evaluate arterial pulse waveform, pulse wave velocity and fetal pulse pressure in normal and growth-restricted fetuses. One hundred fetuses with normal development and 15 fetuses with growth restriction were analyzed. Ultrasonic raw radiofrequency signals were captured from a direction perpendicular to the vascular axis at the fetal diaphragmatic level for the difference in internal dimensions (DID), or simultaneously from different directions for the pulse wave velocity. Pulsatile movement of the proximal and distal intima of the vessels was analyzed using PT. The fetal DID exhibited no significant changes in growth-restricted fetuses. Pulse wave velocity (3.8 ± 0.32 m/s vs. 2.2 ± 0.069 m/s, p < 0.001) and estimated pulse pressure (6.9 ± 0.90 kPa vs. 2.5 ± 0.18 kPa, p < 0.001) were significantly elevated in growth-restricted fetuses. Assessment of DID and pulse wave velocity of the descending aorta using PT is a feasible, non-invasive approach to evaluation of fetal hemodynamics. PMID:25727918

  4. Highly sensitive simple homodyne phase detector for ultrasonic pulse-echo measurements.

    PubMed

    Grossmann, John; Suslov, Alexey; Yong, Grace; Boatner, Lynn A; Svitelskiy, Oleksiy

    2016-04-01

    We have designed and built a modern versatile research-grade instrument for ultrasound pulse-echo probing of the elastic properties of a wide range of materials under laboratory conditions. The heart of the instrument lies in an AD8302 microchip: a gain and phase detector from Analog Devices, Inc. To construct the device, we have implemented a schematic that utilizes the homodyne principle for signal processing instead of the traditional superheterodyne approach. This design allows one to measure phase shifts with high precision and linearity over the entire range of 0°-360°. The system is simple in construction and usage; it makes ultrasound measurements easily accessible to a broad range of researchers. It was tested by measuring the temperature dependence of the ultrasound speed and attenuation in a KTa0.92Nb0.08O3 (KTN) single crystal at a frequency of ∼40 MHz. The tests were performed in the vicinity of the ferroelectric transitions where the large variations of the speed and attenuation demand a detector with outstanding characteristics. The described detector has a wide dynamic range and allows for measuring in a single run over the whole temperature range of the ferroelectric transitions, rather than just in limited intervals available previously. Moreover, due to the wide dynamic range of the gain measurements and high sensitivity this instrument was able to reveal previously unresolvable features associated with the development of the ferroelectric transitions of KTN crystals. PMID:27131694

  5. Nondestructive ultrasonic measurement of bolt preload using the pulsed-phase locked-loop interferometer

    NASA Technical Reports Server (NTRS)

    Allison, S. G.; Heyman, J. S.

    1985-01-01

    Achieving accurate preload in threaded fasteners is an important and often critical problem which is encountered in nearly all sectors of government and industry. Conventional tensioning methods which rely on torque carry with them the disadvantage of requiring constant friction in the fastener in order to accurately correlate torque to preload. Since most of the applied torque typically overcomes friction rather than tensioning the fastener, small variations in friction can cause large variations in preload. An instrument called a pulsed phase locked loop interferometer, which was recently developed at NASA Langley, has found widespread use for measurement of stress as well as material properties. When used to measure bolt preload, this system detects changes in the fastener length and sound velocity which are independent of friction. The system is therefore capable of accurately establishing the correct change in bolt tension. This high resolution instrument has been used for precision measurement of preload in critical fasteners for numerous applications such as the space shuttle landing gear and helicopter main rotors.

  6. Highly sensitive simple homodyne phase detector for ultrasonic pulse-echo measurements

    NASA Astrophysics Data System (ADS)

    Grossmann, John; Suslov, Alexey; Yong, Grace; Boatner, Lynn A.; Svitelskiy, Oleksiy

    2016-04-01

    We have designed and built a modern versatile research-grade instrument for ultrasound pulse-echo probing of the elastic properties of a wide range of materials under laboratory conditions. The heart of the instrument lies in an AD8302 microchip: a gain and phase detector from Analog Devices, Inc. To construct the device, we have implemented a schematic that utilizes the homodyne principle for signal processing instead of the traditional superheterodyne approach. This design allows one to measure phase shifts with high precision and linearity over the entire range of 0°-360°. The system is simple in construction and usage; it makes ultrasound measurements easily accessible to a broad range of researchers. It was tested by measuring the temperature dependence of the ultrasound speed and attenuation in a KTa0.92Nb0.08O3 (KTN) single crystal at a frequency of ˜40 MHz. The tests were performed in the vicinity of the ferroelectric transitions where the large variations of the speed and attenuation demand a detector with outstanding characteristics. The described detector has a wide dynamic range and allows for measuring in a single run over the whole temperature range of the ferroelectric transitions, rather than just in limited intervals available previously. Moreover, due to the wide dynamic range of the gain measurements and high sensitivity this instrument was able to reveal previously unresolvable features associated with the development of the ferroelectric transitions of KTN crystals.

  7. Ultrasonic pulse detection with split spectrum processing and consecutive polarity coincidence

    SciTech Connect

    Ericsson, L.; Stepinski, T.; Dahlgren, S.

    1995-08-01

    The subject of signal processing for material noise reduction has been addressed in a large number of papers during the last decade. Several processing algorithms have been proposed, of which the Split Spectrum Processing (SSP) probably is the most renowned. The SSP technique is based on a synthetic frequency diversity approach, i.e. a filter bank is applied in order to obtain a set of signals with decorrelated noise components. Provided that the target echoes meet certain requirements, they will remain correlated in the generated set of signals. Target echo extraction may then be implemented using a suitable correlation measure. Simple target extractors such as Polarity Thresholding and Amplitude Minimization have been suggested and proven successful if the processing parameters had been correctly tuned. However, parameter tuning is not a trivial matter and relevant echoes may be lost due to the parameter sensitivity. In the paper a new target extraction algorithm, which avoids the requirement for a priori knowledge of frequency range, is introduced. The algorithm, referred to as Consecutive Polarity Coincidence, makes explicit use of the pulse characteristics of the target echo in order to implement local bandwidth estimation. If desired, a gating signal could be constructed by comparing the calculated bandwidth with a user defined threshold. Setting the threshold equal to the frequency range utilized for processing will generate a gating signal identical to the one obtained when using conventional Polarity Thresholding.

  8. Reconstruction of wave features in wind-driven water film flow using ultrasonic pulse-echo technique

    NASA Astrophysics Data System (ADS)

    Liu, Yang; Bond, Leonard J.; Hu, Hui

    2016-02-01

    Aircraft operating in weather conditions that can cause glaze icing face the risk of performance degradation, and increased costs in de-icing procedures. The water run-back in glaze ice accretion can redistribute the impinging water mass and disturb the local flow field, and hence, affect the morphology of ice accretion. Understanding the mechanism of the surface water film transportation is important and challenging, and critical to enabling improvement in the modeling of glaze icing. In this study, an ultrasonic multi-transducer (sparse array) pulse-echo (UMTPE) technique was developed to measure thin film thickness fluctuation. The technical basis for UMTPE technique and the factors that influence the measurements are described. The UMTPE technique was configured to provide time-resolved multi-point thickness measurements. Quantitative measurements of the wind-driven water film flow are achieved by using the UMTPE technique. Point-wise thickness variations can be obtained from each individual channel in the UMTPE system. Span-wise thickness profile can be derived by interpolating the point-wise measurements. The span-wise thickness profiles can be expanded in time domain, which shows the overall flow structures. The velocity of surface wave features is derived by performing a cross-correlation of the upstream and downstream thickness variations, which is then used to transform the temporal thickness fluctuation into the spatial wave structures. The time-resolved spatial flow structures are obtained by applying the transformation along time axis, which present more details of wave structures and the evolution of wave features.

  9. Impedance matching network for high frequency ultrasonic transducer for cellular applications.

    PubMed

    Kim, Min Gon; Yoon, Sangpil; Kim, Hyung Ham; Shung, K Kirk

    2016-02-01

    An approach for the design of an impedance matching network (IMN) for high frequency ultrasonic transducers with large apertures based on impedance analysis for cellular applications is presented in this paper. The main objectives were to maximize energy transmission from the excitation source to the ultrasonic transducers for cell manipulation and to achieve low input parameters for the safe operation of an ultrasonic transducer because the piezoelectric material in high frequency ultrasonic transducers is prone to breakage due to its being extremely thin. Two ultrasonic transducers, which were made of lithium niobate single crystal with the thickness of 15 μm, having apertures of 4.3 mm (fnumber=1.23) and 2.6mm (fnumber=0.75) were tested. L-type IMN was selected for high sensitivity and compact design of the ultrasonic transducers. The target center frequency was chosen as the frequency where the electrical admittance (|Y|) and phase angle (θz) from impedance analysis was maximal and zero, respectively. The reference center frequency and reference echo magnitude were selected as the center frequency and echo magnitude, measured by pulse-echo testing, of the ultrasonic transducer without IMN. Initial component values and topology of IMN were determined using the Smith chart, and pulse-echo testing was analyzed to verify the performance of the ultrasonic transducers with and without IMN. After several iterations between changing component values and topology of IMN, and pulse-echo measurement of the ultrasonic transducer with IMN, optimized component values and topology of IMN were chosen when the measured center frequency from pulse-echo testing was comparable to the target frequency, and the measured echo magnitude was at least 30% larger than the reference echo magnitude. Performance of an ultrasonic transducer with and without IMN was tested by observing a tangible dent on the surface of a plastic petridish and single cell response after an acoustic pulse was

  10. Parallel Transmission Pulse Design with Explicit Control for the Specific Absorption Rate in the Presence of Radiofrequency Errors

    PubMed Central

    Martin, Adrian; Schiavi, Emanuele; Eryaman, Yigitcan; Herraiz, Joaquin L.; Gagoski, Borjan; Adalsteinsson, Elfar; Wald, Lawrence L.; Guerin, Bastien

    2016-01-01

    Purpose A new framework for the design of parallel transmit (pTx) pulses is presented introducing constraints for local and global specific absorption rate (SAR) in the presence of errors in the radiofrequency (RF) transmit chain. Methods The first step is the design of a pTx RF pulse with explicit constraints for global and local SAR. Then, the worst possible SAR associated with that pulse due to RF transmission errors (“worst-case SAR”) is calculated. Finally, this information is used to re-calculate the pulse with lower SAR constraints, iterating this procedure until its worst-case SAR is within safety limits. Results Analysis of an actual pTx RF transmit chain revealed amplitude errors as high as 8% (20%) and phase errors above 3° (15°) for spokes (spiral) pulses. Simulations show that using the proposed framework, pulses can be designed with controlled “worst-case SAR” in the presence of errors of this magnitude at minor cost of the excitation profile quality. Conclusion Our worst-case SAR-constrained pTx design strategy yields pulses with local and global SAR within the safety limits even in the presence of RF transmission errors. This strategy is a natural way to incorporate SAR safety factors in the design of pTx pulses. PMID:26147916

  11. Single-shot temporal envelope measurement of ultrashort extreme-UV pulses by spatially encoded transmission gating.

    PubMed

    Chu, Hsu-hsin; Yang, Chi-Hsiang; Liu, Shih-Cheng; Wang, Jyhpyng

    2015-12-28

    Single-shot ultrashort extreme-UV(EUV) pulse waveform measurement is demonstrated by utilizing strong field ionization of H2 gas for transmission gating. A cross-propagating intense near-IR gate pulse ionizes the EUV absorbing H2 molecules into EUV-non-absorbing H2++ (two protons) and creates a time sweep of transmission encoded spatially across the EUV pulse. The temporal envelope is then retrieved from the lopsided spatial profile of the transmitted pulse. This method not only measures EUV temporal envelope for each single shot, but also determines timing jitter and envelope fluctuation statistically, thus is particularly useful for characterizing low-repetition-rate fluctuating EUV/soft x-ray sources. PMID:26832064

  12. Ultrasonic bone densitometer

    NASA Technical Reports Server (NTRS)

    Hoop, J. M. (Inventor)

    1974-01-01

    A device, for measuring the density of a bone structure so as to monitor the calcium content, is described. A pair of opposed spaced ultrasonic transducers are held within a clamping apparatus closely adjacent the bone being analyzed. These ultrasonic transducers incude piezoelectric crystals shaped to direct signals through the bone encompassed in the heel and finger of the subject being tested. A pulse generator is coupled to one of the transducers and generates an electric pulse for causing the transducers to generate an ultrasonic sound wave which is directed through the bone structure to the other transducer. An electric circuit, including an amplifier and a bandpass filter couples the signals from the receiver transducer back to the pulse generator for retriggering the pulse generator at a frequency proportional to the duration that the ultrasonic wave takes to travel through the bone structure being examined.

  13. Evaluating the CDM-Robustness of the input buffer with very fast transmission line pulse

    NASA Astrophysics Data System (ADS)

    Kao, Tzu-Cheng; Lee, Jian-Hsing; Hung, Chung-Yu; Lien, Chen-Hsin; Su, Hung-Der

    2015-02-01

    In this paper, a scheme for how to utilize VFTLP (very fast transmission line pulse) data to design an input buffer circuit for CDM (charged-device model) ESD protection is reported. The impedance of the ESD device under VFTLP stress is nearly 120 Ω at the beginning of turn-on transient, and decreases with time toward 10 Ω prior to the voltage falling below 0 V. In this work, the fact that the dynamic-characteristic impedance of the ESD device under VFTLP testing is independent of the stress current is found. Since both VFTLP zapping and the CDM are nanosecond events, the dynamic-characteristic impedance of the ESD device can be used to evaluate the CDM threshold voltage of the input buffer based on the equivalent and simplified RLC circuit.

  14. High spatial resolution fast-neutron imaging detectors for Pulsed Fast-Neutron Transmission Spectroscopy

    NASA Astrophysics Data System (ADS)

    Mor, I.; Vartsky, D.; Bar, D.; Feldman, G.; Goldberg, M. B.; Katz, D.; Sayag, E.; Shmueli, I.; Cohen, Y.; Tal, A.; Vagish, Z.; Bromberger, B.; Dangendorf, V.; Mugai, D.; Tittelmeier, K.; Weierganz, M.

    2009-05-01

    Two generations of a novel detector for high-resolution transmission imaging and spectrometry of fast-neutrons are presented. These devices are based on a hydrogenous fiber scintillator screen and single- or multiple-gated intensified camera systems (ICCD). This detector is designed for energy-selective neutron radiography with nanosecond-pulsed broad-energy (1-10 MeV) neutron beams. Utilizing the Time-of-Flight (TOF) method, such a detector is capable of simultaneously capturing several images, each at a different neutron energy (TOF). In addition, a gamma-ray image can also be simultaneously registered, allowing combined neutron/gamma inspection of objects. This permits combining the sensitivity of the fast-neutron resonance method to low-Z elements with that of gamma radiography to high-Z materials.

  15. System Performance Testing of the Pulse-Echo Ultrasonic Instrument for Critical Velocity Determination during Hanford Tank Waste Transfer Operations - 13584

    SciTech Connect

    Denslow, Kayte M.; Bontha, Jagannadha R.; Adkins, Harold E.; Jenks, Jeromy W.J.; Hopkins, Derek F.; Thien, Michael G.; Kelly, Steven E.; Wooley, Theodore A.

    2013-07-01

    The delivery of Hanford double-shell tank waste to the Hanford Tank Waste Treatment and Immobilization Plant (WTP) is governed by specific Waste Acceptance Criteria that are identified in ICD 19 - Interface Control Document for Waste Feed. Waste must be certified as acceptable before it can be delivered to the WTP. The fluid transfer velocity at which solid particulate deposition occurs in waste slurry transport piping (critical velocity) is a key waste acceptance parameter that must be accurately characterized to determine if the waste is acceptable for transfer to the WTP. Washington River Protection Solutions and the Pacific Northwest National Laboratory have been evaluating the ultrasonic PulseEcho instrument since 2010 for its ability to detect particle settling and determine critical velocity in a horizontal slurry transport pipeline for slurries containing particles with a mean particle diameter of =14 micrometers (μm). In 2012 the PulseEcho instrument was further evaluated under WRPS' System Performance test campaign to identify critical velocities for slurries that are expected to be encountered during Hanford tank waste retrieval operations or bounding for tank waste feed. This three-year evaluation has demonstrated the ability of the ultrasonic PulseEcho instrument to detect the onset of critical velocity for a broad range of physical and rheological slurry properties that are likely encountered during the waste feed transfer operations between the Hanford tank farms and the WTP. (authors)

  16. System Performance Testing of the Pulse-Echo Ultrasonic Instrument for Critical Velocity Determination during Hanford Tank Waste Transfer Operations - 13584

    SciTech Connect

    Denslow, Kayte M.; Bontha, Jagannadha R.; Adkins, Harold E.; Jenks, Jeromy WJ; Hopkins, Derek F.; Thien, Michael G.; Kelly, Steven E.; Wooley, Theodore A.

    2013-06-01

    The delivery of Hanford double-shell tank waste to the Hanford Tank Waste Treatment and Immobilization Plant (WTP) is governed by specific Waste Acceptance Criteria that are identified in ICD 19 - Interface Control Document for Waste Feed. Waste must be certified as acceptable before it can be delivered to the WTP. The fluid transfer velocity at which solid particulate deposition occurs in waste slurry transport piping (critical velocity) is a key waste acceptance parameter that must be accurately characterized to determine if the waste is acceptable for transfer to the WTP. Washington River Protection Solutions and the Pacific Northwest National Laboratory have been evaluating the ultrasonic PulseEcho instrument since 2010 for its ability to detect particle settling and determine critical velocity in a horizontal slurry transport pipeline for slurries containing particles with a mean particle diameter of ≥14 micrometers (μm). In 2012 the PulseEcho instrument was further evaluated under WRPS’ System Performance test campaign to identify critical velocities for slurries that are expected to be encountered during Hanford tank waste retrieval operations or bounding for tank waste feed. This three-year evaluation has demonstrated the ability of the ultrasonic PulseEcho instrument to detect the onset of critical velocity for a broad range of physical and rheological slurry properties that are likely encountered during the waste feed transfer operations between the Hanford tank farms and the WTP.

  17. A qualitative and quantitative investigation of the uncracked and cracked condition of concrete beams using impulse excitation, acoustic emission, and ultrasonic pulse velocity techniques

    NASA Astrophysics Data System (ADS)

    Iliopoulos, S.; Iliopoulos, A.; Pyl, L.; Sol, H.; Aggelis, D. G.

    2014-04-01

    The Impulse Excitation Technique (IET) is a useful tool for characterizing the structural condition of concrete. Processing the obtained dynamic parameters (damping ratio, response frequency) as a function of response amplitude, clear and systematic differences appear between intact and cracked specimens, while factors like age and sustained load are also influential. Simultaneously, Acoustic Emission (AE) and Ultrasonic Pulse Velocity (UPV) techniques are used during the three point bending test of the beams in order to supply additional information on the level of damage accumulation which resulted in the specific dynamic behavior revealed by the IET test.

  18. Ultrasonic flow measurements for irrigation process monitoring

    NASA Astrophysics Data System (ADS)

    Ziani, Elmostafa; Bennouna, Mustapha; Boissier, Raymond

    2004-02-01

    This paper presents the state of the art of the general principle of liquid flow measurements by ultrasonic method, and problems of flow measurements. We present an ultrasonic flowmeter designed according to smart sensors concept, for the measurement of irrigation water flowing through pipelines or open channels, using the ultrasonic transit time approach. The new flowmeter works on the principle of measuring time delay differences between sound pulses transmitted upstream and downstream in the flowing liquid. The speed of sound in the flowing medium is eliminated as a variable because the flowrate calculations are based on the reciprocals of the transmission times. The transit time difference is digitally measured by means of a suitable, microprocessor controlled logic. This type of ultrasonic flowmeter will be widely used in industry and water management, it is well studied in this work, followed by some experimental results. For pressurized channels, we use one pair of ultrasonic transducer arranged in proper positions and directions of the pipe, in this case, to determine the liquid velocity, a real time on-line analysis taking account the geometries of the hydraulic system, is applied to the obtained ultrasonic data. In the open channels, we use a single or two pairs of ultrasonic emitter-receiver according to the desired performances. Finally, the goals of this work consist in integrating the smart sensor into irrigation systems monitoring in order to evaluate potential advantages and demonstrate their performance, on the other hand, to understand and use ultrasonic approach for determining flow characteristics and improving flow measurements by reducing errors caused by disturbances of the flow profiles.

  19. Transmission of reactive pulsed laser deposited VO2 films in the THz domain

    NASA Astrophysics Data System (ADS)

    Émond, Nicolas; Hendaoui, Ali; Ibrahim, Akram; Al-Naib, Ibraheem; Ozaki, Tsuneyuki; Chaker, Mohamed

    2016-08-01

    This work reports on the characteristics of the insulator-to-metal transition (IMT) of reactive pulsed laser deposited vanadium dioxide (VO2) films in the terahertz (THz) frequency range, namely the transition temperature TIMT, the amplitude contrast of the THz transmission over the IMT ΔA, the transition sharpness ΔT and the hysteresis width ΔH. XRD analysis shows the sole formation of VO2 monoclinic structure with an enhancement of (011) preferential orientation when varying the O2 pressure (PO2) during the deposition process from 2 to 25 mTorr. THz transmission measurements as a function of temperature reveal that VO2 films obtained at low PO2 exhibit low TIMT, large ΔA, and narrow ΔH. Increasing PO2 results in VO2 films with higher TIMT, smaller ΔA, broader ΔH and asymmetric hysteresis loop. The good control of the VO2 IMT features in the THz domain could be further exploited for the development of advanced smart devices, such as ultrafast switches, modulators, memories and sensors.

  20. Localisation and direction of mitral regurgitant flow in mitral orifice studied with combined use of ultrasonic pulsed Doppler technique and two dimensional echocardiography.

    PubMed Central

    Miyatake, K; Nimura, Y; Sakakibara, H; Kinoshita, N; Okamoto, M; Nagata, S; Kawazoe, K; Fujita, T

    1982-01-01

    Regurgitant flow was analysed in 40 cases of mitral regurgitation, using combined ultrasonic pulsed Doppler technique and two dimensional echocardiography. Abnormal Doppler signals indicative of mitral regurgitant flow were detected in reference to the two dimensional image of the long axis view of the heart and the short axis view at the level of the mitral orifice. The overall direction of regurgitant flow into the left atrium was clearly seen in 28 of 40 cases, and the localisation of regurgitant flow in the mitral orifice in 38 cases. In cases with mitral valve prolapse of the anterior leaflet or posterior leaflet the regurgitant flow was directed posteriorly or anteriorly, respectively. The prolapse occurred at the anterolateral commissure or posteromedial commissure and resulted in regurgitant flow located near the anterolateral commissure or posteromedial commissure of the mitral orifice, respectively. In cases with rheumatic mitral regurgitation the regurgitant flow is usually towards the central portion of the left atrium and is sited in the mid-part of the orifice. The Doppler findings were consistent with left ventriculography and surgical findings. The ultrasonic pulsed Doppler technique combined with two dimensional echocardiography is useful for non-invasive analysis and preoperative assessment of mitral regurgitation. Images PMID:7138708

  1. Statistical analysis of ultrasonic measurements in concrete

    NASA Astrophysics Data System (ADS)

    Chiang, Chih-Hung; Chen, Po-Chih

    2002-05-01

    Stress wave techniques such as measurements of ultrasonic pulse velocity are often used to evaluate concrete quality in structures. For proper interpretation of measurement results, the dependence of pulse transit time on the average acoustic impedance and the material homogeneity along the sound path need to be examined. Semi-direct measurement of pulse velocity could be more convenient than through transmission measurement. It is not necessary to assess both sides of concrete floors or walls. A novel measurement scheme is proposed and verified based on statistical analysis. It is shown that Semi-direct measurements are very effective for gathering large amount of pulse velocity data from concrete reference specimens. The variability of measurements is comparable with that reported by American Concrete Institute using either break-off or pullout tests.

  2. Ultrasonic Monitor

    NASA Technical Reports Server (NTRS)

    1983-01-01

    MicroUltrasonics PLR-1000 is a refined microprocessor-controlled version (usable on bolts, plates, liquids and gases) of the P2L2 developed by Langley Research Center. New technique is for nondestructive measurement of residual stress in various types of structures, for example, nuclear pressure vessels, pipes in nuclear reactors, offshore platforms, bridges, railroad tracks and wheels, aircraft wings, and engines. The instrument produces sound tone pulses that travel through a test specimen. PLR-1000 precisely measures speeds as stress increases speed of sound, tone changes, making precise measurements possible.

  3. Defect detection and size estimation in billet from profile of time-of-flight using ultrasonic transmission method with linear scanning

    NASA Astrophysics Data System (ADS)

    Miyamoto, Ryusuke; Mizutani, Koichi; Ebihara, Tadashi; Wakatsuki, Naoto

    2015-07-01

    In this study, defect detection and size estimation in billet by transmission method with linear scanning were carried out and the validity of the method was evaluated by numerical simulation. In addition, the suitable signal frequency and aperture of transducers were clarified. As a result, the following were found: a defect can be detected, signals with frequencies lower than those generally used in conventional ultrasonic testing (i.e., 0.5-1.5 MHz) are desirable, and the time-of-flight (TOF) deviation Δτ becomes largest when the wavelength at center frequency and the aperture of transducers are comparable. Defect size can be estimated when a single defect exists alone and the defect is not near the surface of a billet. Although defect size estimation becomes difficult when the defect is near the surface of a billet, the defect can be detected by our proposed method.

  4. Ringing in the pulse response of long and wideband coaxial transmission lines due to group delay dispersion

    SciTech Connect

    Kotzian,G.; de Maria,R.; Caspers, F.; Federmann, S.; Hofle, W.

    2009-05-04

    In particle accelerators coaxial cables are commonly used to transmit wideband beam signals covering many decades of frequencies over long distances. Those transmission lines often have a corrugated outer and/or inner conductor. This particular construction exhibits a significant amount of frequency dependent group delay variation. A comparison of simulations based on theoretical models, numerical simulations and S{sub 21} network analyzer measurements up to 2.5 GHz is presented. It is shown how the non-linear phase response and varying group delay leads to ringing in the pulse response and subsequent distortion of signal s transmitted through such coaxial transmission lines.

  5. AXIAL TRANSMISSION METHOD FOR LONG BONE FRACTURE EVALUATION BY ULTRASONIC GUIDED WAVES: SIMULATION, PHANTOM AND IN VITRO EXPERIMENTS

    PubMed Central

    Xu, Kailiang; Ta, Dean; He, Runxin; Qin, Yi-Xian; Wang, Weiqi

    2016-01-01

    Mode conversion occurs when the ultrasonic guided waves encounter fractures. The aim of this study was to investigate the feasibility of fracture assessment in long cortical bone using guided-mode conversion. Mode conversion behavior between the fundamental modes S0 and A0 was analyzed. The expressions proposed for modal velocity were used to identify the original and converted modes. Simulations and phantom experiments were performed using 1.0-mm-thick steel plates with a notch width of 0.5 mm and notch depths of 0.2, 0.4, 0.6 and 0.8 mm. Furthermore, in vitro experiments were carried out on nine ovine tibias with 1.0-mm-wide partial transverse gap break and cortical thickness varying from 2.10 to 3.88 mm. The study confirmed that mode conversion gradually becomes observable as fracture depth increases. Energy percentages of the converted modes correlated strongly with fracture depth, as illustrated by the frequency-sweeping experiments on steel phantoms (100–1100 kHz, r2 = 0.97, p < 0.0069) and the fixed-frequency experiments on nine ovine tibias (250 kHz, r2 = 0.97, p < 0.0056). The approaches described, including mode excitation, velocity expressions and energy percentage criteria, may also contribute to ultrasonic monitoring of long bone fracture healing. PMID:24433749

  6. Transmission of laser pulses with high output beam quality using step-index fibers having large cladding

    DOEpatents

    Yalin, Azer P; Joshi, Sachin

    2014-06-03

    An apparatus and method for transmission of laser pulses with high output beam quality using large core step-index silica optical fibers having thick cladding, are described. The thick cladding suppresses diffusion of modal power to higher order modes at the core-cladding interface, thereby enabling higher beam quality, M.sup.2, than are observed for large core, thin cladding optical fibers. For a given NA and core size, the thicker the cladding, the better the output beam quality. Mode coupling coefficients, D, has been found to scale approximately as the inverse square of the cladding dimension and the inverse square root of the wavelength. Output from a 2 m long silica optical fiber having a 100 .mu.m core and a 660 .mu.m cladding was found to be close to single mode, with an M.sup.2=1.6. Another thick cladding fiber (400 .mu.m core and 720 .mu.m clad) was used to transmit 1064 nm pulses of nanosecond duration with high beam quality to form gas sparks at the focused output (focused intensity of >100 GW/cm.sup.2), wherein the energy in the core was <6 mJ, and the duration of the laser pulses was about 6 ns. Extending the pulse duration provided the ability to increase the delivered pulse energy (>20 mJ delivered for 50 ns pulses) without damaging the silica fiber.

  7. Transmission electron microscopy of Listeria innocua treated by pulsed electric fields and nisin in skimmed milk.

    PubMed

    Calderón-Miranda, M L; Barbosa-Cánovas, G V; Swanson, B G

    1999-10-01

    Pulsed electric fields (PEF) is a nonthermal food preservation process where organoleptic and nutritional properties of the food are maintained. PEF is known to inactivate microorganisms by causing dielectric breakdown of the cell membrane, thus altering the functionality of the membrane as a semipermeable barrier. The extent of damage of the cell membrane, whether visible in the form of a pore or as loss of membrane functionality leads to the inactivation of the microorganism. The objective of this study was to investigate under transmission electron microscopy (TEM) the morphological changes on Listerit innocua as a result of PEF treatment in skimmed milk containing nisin. L. innocua was subjected to PEF at selected electric field intensities of 30, 40, and 50 kV/cm. L. innocua was treated by PEF in both skimmed milk with and without 37 IU nisin/ml. L. innocua treated by PEF in skimmed milk exhibited an increase in the cell wall roughness. cytoplasmic clumping, leakage of cellular material, and rupture of the cell walls and cell membranes. L. innocua subjected to PEF in skimmed milk containing 37 IU nisin/ml exhibited an increased cell wall width. At the highest electric field intensity, 50 kV/cm, elongation of the cell length was observed. There were no morphological differences between cells treated by PEF in skimmed milk with or without nisin. The combination of PEF and nisin exhibit an additive effect in the morphological damage observed on L. innocua. Pore formation was observed on L. innocua for an electric field intensity of 40 kV/cm. The inactivation of L. innocua was a consequence of rupture of the cell membrane and loss of cell membrane functionality. PMID:10563461

  8. Binary Solvent Extraction System and Extraction Time Effects on Phenolic Antioxidants from Kenaf Seeds (Hibiscus cannabinus L.) Extracted by a Pulsed Ultrasonic-Assisted Extraction

    PubMed Central

    Lau, Hwee Wen; Nyam, Kar Lin

    2014-01-01

    The aim of this study was to determine the best parameter for extracting phenolic-enriched kenaf (Hibiscus cannabinus L.) seeds by a pulsed ultrasonic-assisted extraction. The antioxidant activities of ultrasonic-assisted kenaf seed extracts (KSE) were determined by a 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity assay, 2,2′-azino-bis(3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) radical scavenging assay, β-carotene bleaching inhibition assay, and ferric reducing antioxidant power (FRAP) assay. Total phenolic content (TPC) and total flavonoid content (TFC) evaluations were carried out to determine the phenolic and flavonoid contents in KSE. The KSE from the best extraction parameter was then subjected to high performance liquid chromatography (HPLC) to quantify the phenolic compounds. The optimised extraction condition employed 80% ethanol for 15 min, with the highest values determined for the DPPH, ABTS, and FRAP assay. KSE contained mainly tannic acid (2302.20 mg/100 g extract) and sinapic acid (1198.22 mg/100 g extract), which can be used as alternative antioxidants in the food industry. PMID:24592184

  9. Ultrasonic imaging of hidden defects using dry-coupled ultrasonic probes

    NASA Astrophysics Data System (ADS)

    Komsky, Igor N.

    2006-03-01

    Safety criteria of aircraft industry require careful inspection of aircraft components for structural integrity since airworthiness of aging aircraft can be significantly affected by combination of corrosion and fatigue damage. Surface defects can be efficiently detected by visual or other surface inspection techniques. Detection of hidden defects, on the other hand, is still a challenging task. Therefore, it is essential to develop non-destructive methods that can inspect different layers of the aircraft structures for internal defects before they become a safety concern. Ultrasonic probes with the dry-coupled substrates are highly efficient for all modalities of ultrasonic techniques including pulse-echo, pitch-catch, or through-transmission modes. The probes can be deployed in conjunction with portable ultrasonic instruments for B- and C-scanning. The dry-coupled probes have already been tested on a number of aircraft for rapid inspections of the aircraft structures from the outside without any disassembly. However, adequate inspection for small pitting corrosion and incipient fatigue cracks in metallic structures or delaminations in composite panels may require superior sensitivity and resolution of the applied ultrasonic technique. Several novel configurations of the dry-coupled probes with increased sensitivity and resolution will be presented. Ultrasonic imaging with single- or double-element dry-coupled probes will be demonstrated on the specimens with heavy pitting corrosion, machined planar and volumetric defects, and embedded internal flaws.

  10. Design of high-efficiency broad-bandwidth pulse compression device based on composite transmission grating with high damage threshold

    NASA Astrophysics Data System (ADS)

    Chen, Xinrong; Li, Chaoming; Liu, Linyue; Li, Lin; Wu, Jianhong; Chang, Zenghu

    2014-11-01

    A novel pulse compression device has been developed for femto-second Ti: sapphire laser at 800nm center wavelength with 700nm~900nm bandwidth. This new kind of composite pulse compression device consists of two fused silica transmission gratings with 1250lp/mm and 3300lp/mm respectively and these two fused silica transmission gratings are located in two optical surfaces of the same fused silica plate. Owing to use anti-reflection transmission gratings with high space frequency (3300lp/mm), it can avoid the wave-front distort derived from coating antireflection film on one surface of the fused silica plate. Being made of fused silica, this new composite pulse compression device will be expected to have high laser damage threshold. The calculation results show that: the -1st order diffraction efficiency of 1250lp/mm grating is over 87% within the 700nm and 900nm broad-bandwidth for rectangular groove and TE polarization state. And the average diffraction efficiency within the 700nm and 900nm broad-bandwidth is more than 92%. At 800nm, the -1st transmitted order diffraction efficiency is great to 96% while the transmittance of 3300lp/mm grating is up to 99.9%.

  11. Arctic acoustics ultrasonic modeling studies

    NASA Astrophysics Data System (ADS)

    Chamuel, Jacques R.

    1990-03-01

    A unique collection of laboratory ultrasonic modeling results are presented revealing and characterizing hidden pulsed seismoacoustic wave phenomena from 3-D range dependent liquid/solid boundaries. The research succeeded in isolating and identifying low frequency (10 to 500 Hz) transmission loss mechanisms and provided physical insight into Arctic acoustic problems generally beyond the state-of-the-art of theoretical and numerical analysis. The ultrasonic modeling studies dealt with controversial issues and existing discrepancies on seismo-acoustic waves at water/ice interface, sea ice thickness determination, low frequency transmission loss, and bottom leaky Rayleigh waves. The areas investigated include leaky Rayleigh waves at water/ice interface, leaky flexural waves in floating ice plates, effects of dry/wet cracks in sea ice on plate waves and near grazing acoustic waves, edge waves in floating plates, low frequency backscatter from ice keel width resonances, conversion of underwater acoustic waves into plate waves by keels, nondispersive flexural wave along apex of small angle solid wedge, Scholte and leaky Rayleigh waves along apex of immersed 90 ice wedge, backscatter from trailing edge of floes, floating plate resonances associated with near-grazing underwater acoustic waves, acoustic coupling between adjacent floes, and multiple bottom leaky Rayleigh wave components in water layer over solid bottom.

  12. Ultrasonic Imaging of Reaction Wood in Standing Trees

    NASA Astrophysics Data System (ADS)

    Brancheriau, Loic; Saadat-Nia, Mohammad Ali; Gallet, Philippe; Lasaygues, Philippe; Pourtahmasi, Kambiz; Kaftandjian, Valerie

    Wood is an orthotropic material and its properties depend on its age but also depend on environmental growing conditions. An important feature of property alteration is reaction wood formation. Reaction wood forms when part of a tree is subjected to mechanical stress, and helps to bring parts of the plant into an optimal position. This article aims to study the effect of reaction wood on ultrasonic wave propagation using tomographic imaging. The ultrasonic emission was a pulse train of square wave. The peak frequency was 80 kHz. Two logs of poplar and spruce were tested because of the presence of different types of reaction wood (tension wood for poplar and compression wood for spruce). Maps were computed according to the Radon theory and using a filtered back projection algorithm with fan beam geometry. The intrinsic parameters were the slowness (s/m) and attenuation (dB/m at 80 kHz). In addition to ultrasonic tests, X-ray imaging in transmission was used. The ultrasonic maps were analyzed to highlight the differences between normal wood and observed reaction zones. The X-ray images were also compared to ultrasonic maps and the relationships between X-ray attenuation and ultrasonic parameters were discussed.

  13. [Application of Paired-Pulse Stimulation for the Measurement of Inhibitory Transmission from the Hippocampal CA1 Field Potentials].

    PubMed

    Kudryashova, I V

    2015-01-01

    Short-term modifications of postsynaptic responses to paired-pulse stimulation depend not only on presynaptic facilitation. IPSP generated immediately after EPSP in response to the first stimulus is superimposed to synaptic facilitation, decreasing PPF at the shortest interpulse intervals or even producing paired-pulse depression. This effect can be used to measure the efficacy of inhibitory transmission specifically in the hippocampal CA1 area. Comparison of paired-pulse ratio was performed by different methods for the better extraction of GABA(A) IPSP involvement into CA1 field potentials of the rat hippocampal slices. Paired-pulse stimuli were delivered with the set of different stimulus intensity and two interpulse intervals--70 and 15 ms. PPF changes in accordance with exponential decrease of presynaptic residual calcium were observed mainly at low stimuli intensities, but more intensive activation suppressed PPF15 relative to PPF70, sometimes up to paired-pulse depression. The difference of the second in pair amplitudes (A2(15)-A2(70)) upon stimulus intensity corresponded to linear function with a negative slope. The negativity disappeared after bicuculline treatment, suggesting the involvement of GABA(A) inhibition. Therefore individual gradients of these functions can be considered as the coefficients of inhibition to measure its modifications in on-line regime. PMID:26080594

  14. Ultrasonic determination of recrystallization

    NASA Technical Reports Server (NTRS)

    Generazio, E. R.

    1986-01-01

    Ultrasonic attenuation was measured for cold worked Nickel 200 samples annealed at increasing temperatures. Localized dislocation density variations, crystalline order and colume percent of recrystallized phase were determined over the anneal temperature range using transmission electron microscopy, X-ray diffraction, and metallurgy. The exponent of the frequency dependence of the attenuation was found to be a key variable relating ultrasonic attenuation to the thermal kinetics of the recrystallization process. Identification of this key variable allows for the ultrasonic determination of onset, degree, and completion of recrystallization.

  15. Ultrasonic Technologies for Advanced Process Monitoring, Measurement, and Control

    SciTech Connect

    Bond, Leonard J. ); Morra, Marino ); Greenwood, Margaret S. ); Bamberger, Judith A. ); Pappas, Richard A. )

    2003-06-02

    Ultrasonic signals are well suited to the characterization of liquids, slurries and multi-phase flows. Ultrasound sensor systems provide real-time, in-situ measurements or visualizations and the sensing systems are compact, rugged and relatively inexpensive. The objective is to develop ultrasonic sensors that (1) can be attached permanently to a pipeline wall, possibly as a spool piece inserted into the line and (2) can clamp onto an existing pipeline wall and be movable to another location. Two examples of systems based on pulse-echo and transmission signal analysis are used to illustrate some of the capabilities of ultrasonic on-line measurements with technologies that have use in the nuclear, petro-chemical, and food process industries.

  16. Pulse-echo ultrasonic inspection system for in-situ nondestructive inspection of Space Shuttle RCC heat shields.

    SciTech Connect

    Roach, Dennis Patrick; Walkington, Phillip D.; Rackow, Kirk A.

    2005-06-01

    The reinforced carbon-carbon (RCC) heat shield components on the Space Shuttle's wings must withstand harsh atmospheric reentry environments where the wing leading edge can reach temperatures of 3,000 F. Potential damage includes impact damage, micro cracks, oxidation in the silicon carbide-to-carbon-carbon layers, and interlaminar disbonds. Since accumulated damage in the thick, carbon-carbon and silicon-carbide layers of the heat shields can lead to catastrophic failure of the Shuttle's heat protection system, it was essential for NASA to institute an accurate health monitoring program. NASA's goal was to obtain turnkey inspection systems that could certify the integrity of the Shuttle heat shields prior to each mission. Because of the possibility of damaging the heat shields during removal, the NDI devices must be deployed without removing the leading edge panels from the wing. Recently, NASA selected a multi-method approach for inspecting the wing leading edge which includes eddy current, thermography, and ultrasonics. The complementary superposition of these three inspection techniques produces a rigorous Orbiter certification process that can reliably detect the array of flaws expected in the Shuttle's heat shields. Sandia Labs produced an in-situ ultrasonic inspection method while NASA Langley developed the eddy current and thermographic techniques. An extensive validation process, including blind inspections monitored by NASA officials, demonstrated the ability of these inspection systems to meet the accuracy, sensitivity, and reliability requirements. This report presents the ultrasonic NDI development process and the final hardware configuration. The work included the use of flight hardware and scrap heat shield panels to discover and overcome the obstacles associated with damage detection in the RCC material. Optimum combinations of custom ultrasonic probes and data analyses were merged with the inspection procedures needed to properly survey the heat

  17. Amide Proton Transfer Imaging of Diffuse Gliomas: Effect of Saturation Pulse Length in Parallel Transmission-Based Technique

    PubMed Central

    Hiwatashi, Akio; Keupp, Jochen; Yamashita, Koji; Kikuchi, Kazufumi; Yoshiura, Takashi; Yoneyama, Masami; Kruiskamp, Marijn J.; Sagiyama, Koji; Takahashi, Masaya; Honda, Hiroshi

    2016-01-01

    In this study, we evaluated the dependence of saturation pulse length on APT imaging of diffuse gliomas using a parallel transmission-based technique. Twenty-two patients with diffuse gliomas (9 low-grade gliomas, LGGs, and 13 high-grade gliomas, HGGs) were included in the study. APT imaging was conducted at 3T with a 2-channel parallel transmission scheme using three different saturation pulse lengths (0.5 s, 1.0 s, 2.0 s). The 2D fast spin-echo sequence was used for imaging. Z-spectrum was obtained at 25 frequency offsets from -6 to +6 ppm (step 0.5 ppm). A point-by-point B0 correction was performed with a B0 map. Magnetization transfer ratio (MTRasym) and ΔMTRasym (contrast between tumor and normal white matter) at 3.5 ppm were compared among different saturation lengths. A significant increase in MTRasym (3.5 ppm) of HGG was found when the length of saturation pulse became longer (3.09 ± 0.54% at 0.5 s, 3.83 ± 0.67% at 1 s, 4.12 ± 0.97% at 2 s), but MTRasym (3.5 ppm) was not different among the saturation lengths in LGG. ΔMTRasym (3.5 ppm) increased with the length of saturation pulse in both LGG (0.48 ± 0.56% at 0.5 s, 1.28 ± 0.56% at 1 s, 1.88 ± 0.56% at 2 s and HGG (1.72 ± 0.54% at 0.5 s, 2.90 ± 0.49% at 1 s, 3.83 ± 0.88% at 2 s). In both LGG and HGG, APT-weighted contrast was enhanced with the use of longer saturation pulses. PMID:27227746

  18. Pulse

    MedlinePlus

    Heart rate; Heart beat ... The pulse can be measured at areas where an artery passes close to the skin. These areas include the: ... side of the foot Wrist To measure the pulse at the wrist, place the index and middle ...

  19. Transmission of 1064 nm laser radiation during ablation with an ultra-short pulse laser (USPL) system

    NASA Astrophysics Data System (ADS)

    Schelle, Florian; Meister, Jörg; Oehme, Bernd; Frentzen, Matthias

    2012-01-01

    During ablation of oral hard tissue with an USPL system a small amount of the incident laser power does not contribute to the ablation process and is being transmitted. Partial transmission of ultra-short laser pulses could potentially affect the dental pulp. The aim of this study was to assess the transmission during ablation and to deduce possible risks for the patient. The study was performed with an Nd:YVO4 laser, emitting pulses with a duration of 8 ps at a wavelength of 1064 nm. A repetition rate of 500 kHz and an average power of 9 W were chosen to achieve high ablation efficiency. A scanner system created square cavities with an edge length of 1 mm. Transmission during ablation of mammoth ivory and dentin slices with a thickness of 2 mm and 5 mm was measured with a power meter, placed directly beyond the samples. Effects on subjacent blood were observed by ablating specimens placed in contact to pork blood. In a separate measurement the temperature increase during ablation was monitored using an infrared camera. The influence of transmission was assessed by tuning down the laser to the corresponding power and then directly irradiating the blood. Transmission during ablation of 2 mm specimens was about 7.7% (ivory) and 9.6% (dentin) of the incident laser power. Ablation of specimens directly in contact to blood caused coagulation at longer irradiation times (t~18s). Direct irradiation of blood with the transmitted power provoked bubbling and smoke formation. Temperature measurements identified heat generation as the main reason for the observed coagulation.

  20. Comparison of X-Ray, Millimeter Wave, Shearography and Through-Transmission Ultrasonic Methods for Inspection of Honeycomb Composites

    NASA Astrophysics Data System (ADS)

    Abou-Khousa, M. A.; Ryley, A.; Kharkovsky, S.; Zoughi, R.; Daniels, D.; Kreitinger, N.; Steffes, G.

    2007-03-01

    Honeycomb composites are increasingly finding utility in a variety of environments and applications, such as aircraft structural components, flight control components, radomes, etc. In-service and environmental stresses can produce unwanted flaws that adversely affect the structural integrity and functionality of these composites. These flaws may be in the forms of disbonds, delaminations, impact damage, crushed honeycomb, moisture intrusion, internal cracks, etc. There are several nondestructive testing (NDT) methods that may be used to inspect these composites for the presence and evaluation of these flaws. Such NDT methods include X-ray computed tomography, near-field millimeter wave, shearography, and ultrasonic testing. To assess the capabilities of these methods for honeycomb composite inspection, two honeycomb composites panels were produced with several embedded flaws and missing material primarily representing planar disbonds at various levels within the thickness of the panels and with different shapes. Subsequently, the aforementioned NDT methods were used to produce images of the two panels. This paper presents the results of these investigations and a comparison among the capabilities of these methods.

  1. Ultrasonic extensometer measures bolt preload

    NASA Technical Reports Server (NTRS)

    Daniels, C. M., Jr.

    1978-01-01

    Extensometer using ultrasonic pulse reflections to measure elongations in tightened belts and studs is much more accurate than conventional torque wrenches in application of specified preload to bolts and other threaded fasteners.

  2. Ferroelectret non-contact ultrasonic transducers

    NASA Astrophysics Data System (ADS)

    Bovtun, V.; Döring, J.; Bartusch, J.; Beck, U.; Erhard, A.; Yakymenko, Y.

    2007-09-01

    Dielectric and electromechanical properties of the cellular polypropylene ferroelectret films (EMFIT), combining strong piezoelectric response with a low density and softness, evidence their high potential for the air-coupled ultrasonic applications. The disadvantage of the low coupling factor is compensated by the extremely low acoustic impedance, which provides excellent matching to air and promises efficient sound transmission through the air transducer interface. The influence of the electrodes on the electromechanical properties was investigated. Electron beam evaporation technology was adapted to the EMFIT films, and films with both-sided Au and Al electrodes were prepared without reducing or suppressing of the electromechanical properties. Finally, prototype transducers based on the EMFIT films were developed. In spite of the simple construction and absence of matching layers, high sensitivity of the EMFIT transducers was proved in the air-coupled ultrasonic experiment. Amplitude and delay time scanned images of the polyethylene step wedge with holes, obtained in both pulse-echo and transmission modes, demonstrate that non-contact ultrasonic imaging and testing with EMFIT transducers is possible.

  3. Ultrasonic thermometer isolation standoffs

    DOEpatents

    Arave, Alvin E.

    1977-01-01

    A method is provided for minimizing sticking of the transmission line to the protective sheath and preventing noise echoes from interfering with signal echoes in an improved high temperature ultrasonic thermometer which includes an ultrasonic transmission line surrounded by a protective sheath. Small isolation standoffs are mounted on the transmission line to minimize points of contact between the transmission line and the protective sheath, the isolation standoffs serving as discontinuities mounted on the transmission line at locations where a signal echo is desired or where an echo can be tolerated. Consequently any noise echo generated by the sticking of the standoff to the protective sheath only adds to the amplitude of the echo generated at the standoff and does not interfere with the other signal echoes.

  4. Effect of bone cortical thickness on velocity measurements using ultrasonic axial transmission: A 2D simulation study

    NASA Astrophysics Data System (ADS)

    Bossy, Emmanuel; Talmant, Maryline; Laugier, Pascal

    2002-07-01

    In recent years, quantitative ultrasound (QUS) has played an increasing role in the assessment of bone status. The axial transmission technique allows to investigate skeletal sites such as the cortical layer of long bones (radius, tibia), inadequate to through-transmission techniques. Nevertheless, the type of propagation involved along bone specimens has not been clearly elucidated. Axial transmission is investigated here by means of two-dimensional simulations at 1 MHz. We focus our interest on the apparent speed of sound (SOS) of the first arriving signal (FAS). Its dependence on the thickness of the plate is discussed and compared to previous work. Different time criteria are used to derive the apparent SOS of the FAS as a function of source-receiver distance. Frequency-wave number analysis is performed in order to understand the type of propagation involved. For thick plates (thickness>lambdabone, longitudinal wavelength in bone), and for a limited range of source-receiver distances, the FAS corresponds to the lateral wave. Its velocity equals the longitudinal bulk velocity of the bone. For plate thickness less than lambdabone, some plate modes contribute to the FAS, and the apparent SOS decreases with the thickness in a way that depends on both the time criterion and on the source-receiver distance. The FAS corresponds neither to the lateral wave nor to a single plate mode. For very thin plates (thicknessbone)/4, the apparent SOS tends towards the velocity of the lowest order symmetrical vibration mode (S0 Lamb mode). copyright 2002 Acoustical Society of America.

  5. Pulse transmission measurements for determining near optimal profile gradings in multimode borosilicate optical fibers.

    PubMed

    Cohen, L G

    1976-07-01

    Dispersive differences between B(2)O(3) and SiCO(2) constituents make nonparabolic profiles optimal equalizers of intermodal group delays in fibers with graded B(2)O(3)-SiO(2) cores and uniform B(2)O(3)-SiO(2) cladding. Pulse dispersion measurements were correlated with profile shapes in a systematic study of multimode fibers with near power law gradients. Far field spatial ray filters were used to diagnose impulse response shapes so that new fibers could be fabricated with closer-to-optimal profile gradients. One of the fibers had an alpha approximately 1.77 power law exponent that was nearly optimal for lambda = 907.5-nm wavelength and caused 2sigma = 0.26-nsec/km full rms output pulse spreading. When expected material dispersion effects were deconvolved from the output pulse spreading, the resultant pulse width was approximately 75 times less than the result expected for a comparable step-index fiber. This is the largest pulse width reduction reported yet. PMID:20165269

  6. Ultrasonic evaluation of high voltage circuit boards

    NASA Technical Reports Server (NTRS)

    Klima, S. J.; Riley, T. J.

    1976-01-01

    Preliminary observations indicate that an ultrasonic scanning technique may be useful as a quick, low cost, nondestructive method for judging the quality of circuit board materials for high voltage applications. Corona inception voltage tests were conducted on fiberglass-epoxy and fiberglass-polyimide high pressure laminates from 20 to 140 C. The same materials were scanned ultrasonically by utilizing the single transducer, through-transmission technique with reflector plate, and recording variations in ultrasonic energy transmitted through the board thickness. A direct relationship was observed between ultrasonic transmission level and corona inception voltage. The ultrasonic technique was subsequently used to aid selection of high quality circuit boards for the Communications Technology Satellite.

  7. Piezoelectric and electrostrictive effects in ferroelectret ultrasonic transducers

    NASA Astrophysics Data System (ADS)

    Döring, Joachim; Bovtun, Viktor; Gaal, Mate; Bartusch, Jürgen; Erhard, Anton; Kreutzbruck, Marc; Yakymenko, Yuriy

    2012-10-01

    Electromechanical response of polypropylene ferroelectret transducers under application of high-voltage pulses was measured by laser Doppler vibrometry and compared with results of ultrasonic through-air transmission between two ferroelectret transducers. The electromechanical response was completely explained by piezoelectric and electrostrictive effects. The electrostrictive effect dominates at high voltages and provides significant enlargement of the transducer constant, up to factor of 2.5. The induced strain of 1.7% was achieved at -2000 V. The nonlinear ultrasonic transmission was shown to be well described by the piezoelectric and electrostrictive response of transmitter, except in the range of high negative exciting voltages where some limitation of the transmitted signal was observed. This limitation seems not to be a fundamental one and does not abolish the advantages of high-voltage excitation of polypropylene ferroelectret transducers.

  8. Quasi-monochromatic bound on ultrashort light-pulse transmission through fog.

    PubMed

    Shapiro, Jeffrey H

    2011-09-01

    The use of ultrashort (femtosecond duration) light pulses for line-of-sight free-space optical (FSO) communication through fog is receiving increasing attention. Assuming that the transmitter power is low enough to preclude nonlinear interactions, and that scattering-induced multipath spread is less than the reciprocal of the scattering-induced Doppler spread, it is shown that the average transmitter-to-receiver fractional energy transfer of an ultrafast FSO system cannot exceed that of a quasimonochromatic (nanosecond pulse duration) system operating at the optimum wavelength within the ultrafast system's spectrum. Thus, an ultrashort-pulse system is not a solution for high-data-rate FSO communication through fog, because, at best, it will reproduce on average the energy-transfer performance of a wavelength-optimized quasimonochromatic system. PMID:21886209

  9. A high-performance ultrasonic system for the simultaneous transmission of data and power through solid metal barriers.

    PubMed

    Lawry, Tristan J; Wilt, Kyle R; Ashdown, Jon D; Scarton, Henry A; Saulnier, Gary J

    2013-01-01

    This paper presents a system capable of simultaneous high-power and high-data-rate transmission through solid metal barriers using ultrasound. By coaxially aligning a pair of piezoelectric transducers on opposite sides of a metal wall and acoustically coupling them to the barrier, an acoustic- electric transmission channel is formed which prevents the need for physical penetration. Independent data and power channels are utilized, but they are only separated by 25.4 mm to reduce the system's form factor. Commercial off-the-shelf components and evaluation boards are used to create realtime prototype hardware and the full system is capable of transmitting data at 17.37 Mbps and delivering 50 W of power through a 63.5-mm thick steel wall. A synchronous multi-carrier communication scheme (OFDM) is used to achieve a very high spectral efficiency and to ensure that there is only minor interference between the power and data channels. Also presented is a discussion of potential enhancements that could be made to greatly improve the power and data-rate capabilities of the system. This system could have a tremendous impact on improving safety and preserving structural integrity in many military applications (submarines, surface ships, unmanned undersea vehicles, armored vehicles, planes, etc.) as well as in a wide range of commercial, industrial, and nuclear systems. PMID:23287924

  10. Transmission or Within-Host Dynamics Driving Pulses of Zoonotic Viruses in Reservoir–Host Populations

    PubMed Central

    Plowright, Raina K.; Peel, Alison J.; Streicker, Daniel G.; Gilbert, Amy T.; McCallum, Hamish; Wood, James; Baker, Michelle L.; Restif, Olivier

    2016-01-01

    Progress in combatting zoonoses that emerge from wildlife is often constrained by limited knowledge of the biology of pathogens within reservoir hosts. We focus on the host–pathogen dynamics of four emerging viruses associated with bats: Hendra, Nipah, Ebola, and Marburg viruses. Spillover of bat infections to humans and domestic animals often coincides with pulses of viral excretion within bat populations, but the mechanisms driving such pulses are unclear. Three hypotheses dominate current research on these emerging bat infections. First, pulses of viral excretion could reflect seasonal epidemic cycles driven by natural variations in population densities and contact rates among hosts. If lifelong immunity follows recovery, viruses may disappear locally but persist globally through migration; in either case, new outbreaks occur once births replenish the susceptible pool. Second, epidemic cycles could be the result of waning immunity within bats, allowing local circulation of viruses through oscillating herd immunity. Third, pulses could be generated by episodic shedding from persistently infected bats through a combination of physiological and ecological factors. The three scenarios can yield similar patterns in epidemiological surveys, but strategies to predict or manage spillover risk resulting from each scenario will be different. We outline an agenda for research on viruses emerging from bats that would allow for differentiation among the scenarios and inform development of evidence-based interventions to limit threats to human and animal health. These concepts and methods are applicable to a wide range of pathogens that affect humans, domestic animals, and wildlife. PMID:27489944

  11. Transmission or Within-Host Dynamics Driving Pulses of Zoonotic Viruses in Reservoir-Host Populations.

    PubMed

    Plowright, Raina K; Peel, Alison J; Streicker, Daniel G; Gilbert, Amy T; McCallum, Hamish; Wood, James; Baker, Michelle L; Restif, Olivier

    2016-08-01

    Progress in combatting zoonoses that emerge from wildlife is often constrained by limited knowledge of the biology of pathogens within reservoir hosts. We focus on the host-pathogen dynamics of four emerging viruses associated with bats: Hendra, Nipah, Ebola, and Marburg viruses. Spillover of bat infections to humans and domestic animals often coincides with pulses of viral excretion within bat populations, but the mechanisms driving such pulses are unclear. Three hypotheses dominate current research on these emerging bat infections. First, pulses of viral excretion could reflect seasonal epidemic cycles driven by natural variations in population densities and contact rates among hosts. If lifelong immunity follows recovery, viruses may disappear locally but persist globally through migration; in either case, new outbreaks occur once births replenish the susceptible pool. Second, epidemic cycles could be the result of waning immunity within bats, allowing local circulation of viruses through oscillating herd immunity. Third, pulses could be generated by episodic shedding from persistently infected bats through a combination of physiological and ecological factors. The three scenarios can yield similar patterns in epidemiological surveys, but strategies to predict or manage spillover risk resulting from each scenario will be different. We outline an agenda for research on viruses emerging from bats that would allow for differentiation among the scenarios and inform development of evidence-based interventions to limit threats to human and animal health. These concepts and methods are applicable to a wide range of pathogens that affect humans, domestic animals, and wildlife. PMID:27489944

  12. SOLITONS AND OPTICAL FIBERS: Multiwavelength pulse transmission in an optical fibre — amplifier system

    NASA Astrophysics Data System (ADS)

    Panoiu, N.-C.; Mel'nikov, I. V.; Mihalache, D.; Etrich, C.; Lederer, F.

    2002-11-01

    The structure and dynamics of solitary waves created in the interaction of multiwavelength pulses in a single-mode optical fibre with amplification, filtering, and amplitude modulation is analysed. It is shown that there is a critical wavelength separation between channels above which wavelength-division multiplexing with solitons is feasible and that this separation increases with the number of channels.

  13. Temperature imaging with speed of ultrasonic transmission tomography for medical treatment control: A physical model-based method

    NASA Astrophysics Data System (ADS)

    Chu, Zhe-Qi; Yuan, Jie; Stephen, Z. Pinter; Oliver, D. Kripfgans; Wang, Xue-Ding; Paul, L. Carson; Liu, Xiao-Jun

    2015-10-01

    Hyperthermia is a promising method to enhance chemo and radiation therapy of breast cancer. In the process of hyperthermia, temperature monitoring is of great importance to assure the effectiveness of treatment. The transmission speed of ultrasound in biomedical tissue changes with temperature. However, when mapping the speed of sound directly to temperature in each pixel as desired for using all speeds of ultrasound data, temperature bipolar edge enhancement artifacts occur near the boundary of two tissues with different speeds of ultrasound. After the analysis of the reasons for causing these artifacts, an optimized method is introduced to rebuild the temperature field image by using the continuity constraint as the judgment criterion. The significant smoothness of the rebuilding image in the transitional area shows that our proposed method can build a more precise temperature image for controlling the medical thermal treatment. Project supported in part by DoD/BCRP Idea Award, BC095397P1, the National Natural Science Foundation of China (Grant No. 61201425), the Natural Science Foundation of Jiangsu Province, China (Grant No. BK20131280), the Priority Academic Program Development of Jiangsu Provincial Higher Education Institutions, China, and the National Institutes of Health (NIH) of United States (Grant Nos. R01AR060350, R01CA91713, and R01AR055179).

  14. Pulse

    MedlinePlus

    ... resting for at least 10 minutes. Take the exercise heart rate while you are exercising. ... pulse rate can help determine if the patient's heart is pumping. ... rate gives information about your fitness level and health.

  15. Transmission line based short pulse generation circuits in a 0.13 μm complementary metal-oxide-semiconductor technology

    NASA Astrophysics Data System (ADS)

    Zou, Huan; Geng, Yongtao; Wang, Pingshan

    2011-02-01

    A few traditional pulse forming circuits are implemented and compared in a commercial 0.13 μm digital CMOS technology. Standard on-chip transmission lines are used as pulse forming lines (PFLs), while CMOS transistors are used as switches. The shortest output pulses of these circuits are analyzed and compared through Cadence Spectre simulations. All the CMOS circuits are fabricated in the commercial technology. Pulses of ˜170 ps durations and 120-400 mV amplitudes are obtained when the power supply is tuned from 1.2 to 2 V. The results show that these traditional PFL based circuits can be implemented in standard CMOS technology for high power short pulse generations. Furthermore, the PFL circuits significantly extend the short pulse generation capabilities of CMOS technologies.

  16. Why Current Doppler Ultrasound Methodology Is Inaccurate in Assessing Cerebral Venous Return: The Alternative of the Ultrasonic Jugular Venous Pulse

    PubMed Central

    2016-01-01

    Assessment of cerebral venous return is growing interest for potential application in clinical practice. Doppler ultrasound (DUS) was used as a screening tool. However, three meta-analyses of qualitative DUS protocol demonstrate a big heterogeneity among studies. In an attempt to improve accuracy, several authors alternatively measured the flow rate, based on the product of the time average velocity with the cross-sectional area (CSA). However, also the quantification protocols lacked of the necessary accuracy. The reasons are as follows: (a) automatic measurement of the CSA assimilates the jugular to a circle, while it is elliptical; (b) the use of just a single CSA value in a pulsatile vessel is inaccurate; (c) time average velocity assessment can be applied only in laminar flow. Finally, the tutorial describes alternative ultrasound calculation of flow based on the Womersley method, which takes into account the variation of the jugular CSA overtime. In the near future, it will be possible to synchronize the electrocardiogram with the brain inflow (carotid distension wave) and with the outflow (jugular venous pulse) in order to nicely have a noninvasive ultrasound picture of the brain-heart axis. US jugular venous pulse may have potential use in neurovascular, neurocognitive, neurosensorial, and neurodegenerative disorders. PMID:27006525

  17. Detection of laser-induced nanosecond ultrasonic pulses in metals using a pancake coil and a piezoelectric sensor.

    PubMed

    Kozhushko, Victor V; Krenn, Heinz

    2012-06-01

    A piezoelectric sensor and a pancake coil sensor were used for broadband detection of laser-induced ultrasound in single-crystal aluminum and polycrystalline nickel. Pressure pulses with pronounced compression phases were induced by laser pulses of 5 ns duration from one side of the specimens and detected from the opposite side. A coupling layer of water was required for the piezoelectric method, whereas the pancake coil placed in the biasing permanent field of a cylindrical magnet ~0.25 T allowed noncontact detection. The signals detected by a piezoelectric transducer showed bipolar form and their spectra covered the range from 5 to 90 MHz. The signal measured in aluminum by a pancake coil was assigned to the eddy current sources and had single polarity. The peak-to-peak value of the signal in nickel was higher and had bipolar form because of the inverse magnetostrictive effect. The high-frequency limit detected by the pancake coil approached 200 MHz. PMID:22718873

  18. Improved ultrasonic biomedical measuring apparatus

    NASA Technical Reports Server (NTRS)

    Lee, R. D.

    1972-01-01

    Device for making measurements of organs in living specimens and recording movements of organs is described. System uses series of ultrasonic pulses beamed into body of animal and reflected echo pulses are picked up by transducers and recorded. Diagram of equipment required and method of application is included.

  19. Ultrasonic monitoring of material processing using clad buffer rod sensors

    NASA Astrophysics Data System (ADS)

    Ramos Franca, Demartonne

    Ultrasonic sensors and techniques are developed for in-line monitoring of polymer extrusion, cleanliness of molten metals and liquid flow speed at elevated temperature. Pulse-echo mode is used for the first two processes, while the through-transmission mode is applied in the third one. The ultrasonic probe consists of high performance clad buffer rods with different dimensions to thermally isolate the commercial ultrasonic transducer from materials at high temperature. The clad buffer rods are made of steel, polymer and ceramic. Steel clad buffer rods are introduced for in-line monitoring of polymer extrusion processes. Owing to its superior performance in pulse-echo mode, for the first time such a probe is installed and performs ultrasonic monitoring in the die of a co-extrusion machine and in the barrel section of a twin-screw extruder. It can reveal a variety of information relevant to process parameters, such as polymer layer thickness, interface location and adhesion quality, stability, or polymer composition change. For the ultrasonic monitoring of polymer processes, probes with acoustic impedance that matches that of the processed polymer may offer certain advantages such as quantitative viscoelastic evaluation; thus high temperature polymer clad buffer rods, in particular PEEK, are developed. It is demonstrated that this new probe exhibits unique advantages for in-line monitoring of the cure of epoxies and polymer extrusion process. Long steel clad buffer rods with a spherical focus lens machined at the probing end are proposed for cleanliness evaluation of molten metals. The potential of this focusing probe is demonstrated by means of high-resolution imaging and particles detection in molten zinc at temperatures higher than 600°C, using a single probe operated at pulse-echo mode. A contrapropagating ultrasonic flowmeter employing steel clad buffer rods is devised to operate at high temperature. It is demonstrated that these rods guide ultrasonic signals

  20. 512QAM Nyquist sinc-pulse transmission at 54 Gbit/s in an optical bandwidth of 3 GHz.

    PubMed

    Schmogrow, R; Hillerkuss, D; Wolf, S; Bäuerle, B; Winter, M; Kleinow, P; Nebendahl, B; Dippon, T; Schindler, P C; Koos, C; Freude, W; Leuthold, J

    2012-03-12

    We demonstrate for the first time transmission of 54 Gbit/s and 48 Gbit/s over 44 km and 150 km, respectively, utilizing an optical bandwidth of only 3 GHz. We used polarization division multiplexed 512QAM and 256QAM modulation formats in combination with Nyquist pulse shaping having virtually zero roll-off. The resulting spectral efficiencies range up to 18 bit/s/Hz and 16 bit/s/Hz, respectively. Taking into account the overhead required for forward error correction, the occupied signal bandwidth corresponds to net spectral efficiencies of 14.4 bit/s/Hz and 15 bit/s/Hz, which could be achieved in a wavelength division multiplexed network without spectral guard bands. PMID:22418526

  1. Transmission properties of terahertz pulses through semiconductor split-ring resonators

    NASA Astrophysics Data System (ADS)

    yun-hong, He; Jiu-sheng, Li

    2011-02-01

    In this paper, two novel planar terahertz semiconductor split-ring resonators are successfully constructed and measured using the commercial software CST Microwave Studio. They exhibit a duel-band and a triple-band transmission property within the frequencies ranging from 0.1THz to 3THz. We have simulated the dual-band planar metamaterial with two distinct electric resonances at 0.81THz and 1.818THz, and triple-band planar metamaterial with three distinct electric resonances at 0.543THz, 1.044THz, and 1.506THz. These developments are further steps towards the development of broadband terahertz devices.

  2. Transmission line pulse properties for a bidirectional transient voltage suppression diode fabricated using low-temperature epitaxy

    NASA Astrophysics Data System (ADS)

    Bouangeune, Daoheung; Cho, Deok-Ho; Yun, Hyung-Joong; Shim, Kyu-Hwan; Choi, Chel-Jong

    2015-01-01

    Based on low temperature epitaxy technology, a bidirectional transient voltage suppression (TVS) diode with abrupt multi-junctions was developed. The bidirectional triggering voltage of ±16 V was controlled by the thickness and dopant concentration in the multi-junctions using a reduced-pressure chemical vapor deposition (RPCVD) process. The manufactured TVS diode showed a small leakage current density and dynamic resistance of less than 5.1 × 10-14 A/ µm2 and 1 O, respectively, which could be associated with the epitaxially grown abrupt multijunctions. The transmission line pulse (TLP) analysis results demonstrated that the bidirectional TVS diodes were capable of withstanding a peak pulse current of up to ±20 A or ±1.02 × 10-3 A/ µm2, which is equivalent to ±40 kV of the human body model (HBM) and ±12 kV of IEC61000-4-2 (IEC). Nevertheless, the electrostatic discharge (ESD) design window showed that bidirectional TVS diodes meet IEC level 4 standard ESD protection requirements (8 kV in contact discharge). In addition, because of the bidirectional structure, the TVS devices exhibited a small capacitance of 4.9 pF, which confirms that the TVS diode can be used for protecting high data rate communication lines (over 500 Mbps) from ESD shock.

  3. Bundled hollow optical fibers for transmission of high-peak-power Q-switched Nd:YAG laser pulses

    NASA Astrophysics Data System (ADS)

    Yilmaz, Ozgur; Miyagi, Mitsunobu; Matsuura, Yuji

    2006-09-01

    A hollow-fiber bundle was designed and used to deliver high-peak-power pulses from a Q-switched Nd:YAG laser. An 80 cm long bundle with a total diameter of 5.5 mm was composed of 37 glass capillaries with bore diameters of 0.7 mm. Beam-resizing optics with two lenses were used to couple the laser beam into the bundle. The measured coupling loss due to the limited aperture ratio of the bundle was 2.3 dB, and the transmission loss at wavelengths of 1064 and 532 nm was 0.3 dB. When an inert gas flowed through the bores of the capillaries, the maximum output pulse energy was 200 mJ, which was the limit of the laser used in the experiment. Hollow-fiber bundles withstand irradiation better than single hollow fibers and silica-glass optical fibers do. They are suitable for many dermatological applications because they can be used to irradiate a large area.

  4. Improvement of ultrasonic characteristics in butt-welded joint of austenitic stainless steel using magnetic stirring method

    SciTech Connect

    Tanosaki, M.; Yoshikawa, K.; Arakawa, T.

    1995-08-01

    Magnetic Stirring Method of Tungsten Inert Gas(TIG) Welding are applied to butt-welded joint of austenitic stainless steel. The purpose of this method is to refine the welded structure and to improve the ultrasonic characteristics. In the conventional method of ultrasonic test in austenitic stainless steel weldments, dendritic solidification structure of weldment prevents smooth ultrasonic beam transmission. The tests are performed in three welding conditions; One is conventional TIG welding (without magnetic stirring), the other two are TIG welding using magnetic stirring method. Each test piece is evaluated by observing macro structure of cross section and by several ultrasonic tests examining pulse amplitudes, beam path length and proceeding beam direction. The detectability of artificial notches in weldment is also investigated and compared.

  5. Experimental study of transmission of a pulsed focused beam through a skull phantom in nonlinear regime

    NASA Astrophysics Data System (ADS)

    Tsysar, S. A.; Nikolaeva, A. V.; Svet, V. D.; Khokhlova, V. A.; Yuldashev, P. V.; Sapozhnikov, O. A.

    2015-10-01

    In the paper the use of receiving and radiating system, which allows to determine the parameters of bone by nonlinear pulse-echo technique and to image of brain structures through the skull bones, was proposed. Accuracy of the skull bone characterization is due to higher measured harmonic and is significantly better than in linear case. In the experimental part focused piezoelectric transducer with diameter 100 mm, focal distance 100 mm, the frequency of 1.092 MHz was used. It was shown that skull bone profiling can be performed with the use of 3rd harmonic since 1st harmonic can be used for visualization of the underlying objects. The use of wideband systems for both skull profiling and brain visualization is restricted by skull attenuation and resulting low effective sensitivity.

  6. Experimental study of transmission of a pulsed focused beam through a skull phantom in nonlinear regime

    SciTech Connect

    Tsysar, S. A. Nikolaeva, A. V.; Khokhlova, V. A.; Yuldashev, P. V.; Svet, V. D.; Sapozhnikov, O. A.

    2015-10-28

    In the paper the use of receiving and radiating system, which allows to determine the parameters of bone by nonlinear pulse-echo technique and to image of brain structures through the skull bones, was proposed. Accuracy of the skull bone characterization is due to higher measured harmonic and is significantly better than in linear case. In the experimental part focused piezoelectric transducer with diameter 100 mm, focal distance 100 mm, the frequency of 1.092 MHz was used. It was shown that skull bone profiling can be performed with the use of 3rd harmonic since 1st harmonic can be used for visualization of the underlying objects. The use of wideband systems for both skull profiling and brain visualization is restricted by skull attenuation and resulting low effective sensitivity.

  7. Temperature dependence of ultrasonic propagation speed and attenuation in excised canine liver tissue measured using transmitted and reflected pulses

    NASA Astrophysics Data System (ADS)

    Techavipoo, U.; Varghese, T.; Chen, Q.; Stiles, T. A.; Zagzebski, J. A.; Frank, G. R.

    2004-06-01

    Previous reported data from our laboratory demonstrated the temperature dependence of propagation speed and attenuation of canine tissue in vitro at discrete temperatures ranging from 25 to 95 °C. However, concerns were raised regarding heating the same tissue specimen over the entire temperature range, a process that may introduce irreversible and, presumably, cumulative tissue degradation. In this paper propagation speed and attenuation vs temperature are measured using multiple groups of samples, each group heated to a different temperature. Sample thicknesses are measured directly using a technique that uses both transmitted and reflected ultrasound pulses. Results obtained using 3 and 5 MHz center frequencies demonstrate a propagation speed elevation of around 20 m/s in the 22-60 °C range, and a decrease of 15 m/s in the 60-90 °C range, in agreement with previous results where the same specimens were subjected to the entire temperature range. However, sound speed results reported here are slightly higher than those reported previously, probably due to more accurate measurements of sample thickness in the present experiments. Results also demonstrate that while the propagation speed varies with temperature, it is not a function of tissue coagulation. In contrast, the attenuation coefficient depends on both tissue coagulation effects and temperature elevation.

  8. Using Pulse Width Modulation for Wireless Transmission of Neural Signals in Multichannel Neural Recording Systems

    PubMed Central

    Yin, Ming; Ghovanloo, Maysam

    2013-01-01

    We have used a well-known technique in wireless communication, pulse width modulation (PWM) of time division multiplexed (TDM) signals, within the architecture of a novel wireless integrated neural recording (WINeR) system. We have evaluated the performance of the PWM-based architecture and indicated its accuracy and potential sources of error through detailed theoretical analysis, simulations, and measurements on a setup consisting of a 15-channel WINeR prototype as the transmitter and two types of receivers; an Agilent 89600 vector signal analyzer and a custom wideband receiver, with 36 and 75 MHz of maximum bandwidth, respectively. Furthermore, we present simulation results from a realistic MATLAB-Simulink model of the entire WINeR system to observe the system behavior in response to changes in various parameters. We have concluded that the 15-ch WINeR prototype, which is fabricated in a 0.5-μm standard CMOS process and consumes 4.5 mW from ±1.5 V supplies, can acquire and wirelessly transmit up to 320 k-samples/s to a 75-MHz receiver with 8.4 bits of resolution, which is equivalent to a wireless data rate of ~ 2.26 Mb/s. PMID:19497823

  9. Using pulse width modulation for wireless transmission of neural signals in multichannel neural recording systems.

    PubMed

    Yin, Ming; Ghovanloo, Maysam

    2009-08-01

    We have used a well-known technique in wireless communication, pulse width modulation (PWM) of time division multiplexed (TDM) signals, within the architecture of a novel wireless integrated neural recording (WINeR) system. We have evaluated the performance of the PWM-based architecture and indicated its accuracy and potential sources of error through detailed theoretical analysis, simulations, and measurements on a setup consisting of a 15-channel WINeR prototype as the transmitter and two types of receivers; an Agilent 89600 vector signal analyzer and a custom wideband receiver, with 36 and 75 MHz of maximum bandwidth, respectively. Furthermore, we present simulation results from a realistic MATLAB-Simulink model of the entire WINeR system to observe the system behavior in response to changes in various parameters. We have concluded that the 15-ch WINeR prototype, which is fabricated in a 0.5- mum standard CMOS process and consumes 4.5 mW from +/-1.5 V supplies, can acquire and wirelessly transmit up to 320 k-samples/s to a 75-MHz receiver with 8.4 bits of resolution, which is equivalent to a wireless data rate of approximately 2.56 Mb/s. PMID:19497823

  10. Ultrasonic Imaging Of Deep Arteries

    NASA Technical Reports Server (NTRS)

    Rooney, James A.; Heyser, Richard C.; Lecroissette, Dennis H.

    1990-01-01

    Swept-frequency sound replaces pulsed sound. Ultrasonic medical instrument produces images of peripheral and coronary arteries with resolutions higher and at depths greater than attainable by previous ultrasonic systems. Time-delay-spectrometry imager includes scanning, image-processing, and displaying equipment. It sweeps in frequency from 0 to 10 MHz in 20 ms, pauses for 5 ms, and repeats sweep. Intended for use in noninvasive detection and measurement of atherosclerotic lesions.

  11. Non-contact ultrasonic defect imaging in composites

    NASA Astrophysics Data System (ADS)

    Tenoudji, F. Cohen; Citerne, J. M.; Dutilleul, H.; Busquet, D.

    2016-02-01

    In the situations where conventional NDT ultrasonic techniques using immersion of the part under inspection or its contact with the transducers cannot be used, in-air investigation presents an alternative. The huge impedance mismatch between the part material and air (transmission loss in the order of 80 dB for a thin metallic plate) induces having to deal very small signals and unfavorable signal to noise ratios. The approach adopted here is the use of the crack of a spark generated by an induction coil as a sound source and an electrostatic polyethylene membrane microphone as a receiver [1]. The advantage of this source is that the spark power is high (several kilowatts) and its power is directly coupled to air during the energy release. In some difficult situations, an elliptical mirror is used to concentrate the sound beam power on the surface of the part [2,3]. Stability and reproducibility of the sound generated by the spark, which are a necessity in order to perform quantitative evaluations, are achieved in our experiment. This permits also an increase of the signal to noise ratio by signal accumulation. The sound pulse duration of few microseconds allows operating in pulse echo in some circumstances. The bandwidth of the source is large, of several hundred of kilohertz, and that of the microphone above 100 kHz allow the flexibility to address different kinds of materials. The technique allows an easy, in-air, non contact, inspection of structural composite parts, with pulse waves, with an excellent signal to noise ratio. An X-Y ultrasonic scanning ultrasonic system for material inspection using this technique has been realized. Results obtained in transmission and reflection are presented. Defects in carbon composite plates and in honeycomb are imaged in transmission Echographic measurements show that defect detection can be performed in thin plates using Lamb waves propagation when only one sided inspection of the part is possible.

  12. Theory of magnetically insulated electron flows in coaxial pulsed power transmission lines

    NASA Astrophysics Data System (ADS)

    Lawconnell, Robert I.; Neri, Jesse

    1990-03-01

    The Cartesian magnetically insulated transmission line (MITL) theory of Mendel et al. [Appl. Phys. 50, 3830 (1979); Phys. Fluids 26, 3628 (1983)] is extended to cylindrical coordinates. A set of equations that describe arbitrary electron flows in cylindrical coordinates is presented. These equations are used to derive a general theory for laminar magnetically insulated electron flows. The laminar theory allows one to specify the potentials, fields, and densities across a coaxial line undergoing explosive electron emission at the cathode. The theory is different from others available in cylindrical coordinates in that the canonical momentum and total energy for each electron may be nonzero across the electron sheath. A nonzero canonical momentum and total energy for the electrons in the sheath allows the model to produce one-dimensional flows that resemble flows from lines with impedance mismatches and perturbing structures. The laminar theory is used to derive two new self-consistent cylindrical flow solutions: (1) for a constant density profile and (2) for a quadratic density profile of the form ρ=ρc[(r2m-r2)/(r2m-r2c)]. This profile is of interest in that it is similar to profiles observed in a long MITL simulation [Appl. Phys. 50, 4996 (1979)]. The theoretical flows are compared to numerical results obtained with two-dimensional (2-D) electromagnetic particle-in-cell (PIC) codes.

  13. Nonlinear electromechanical response of the ferroelectret ultrasonic transducers

    NASA Astrophysics Data System (ADS)

    Döring, Joachim; Bovtun, Viktor; Bartusch, Jürgen; Erhard, Anton; Kreutzbruck, Marc; Yakymenko, Yuriy

    2010-08-01

    The ultrasonic transmission between two air-coupled polypropylene (PP) ferroelectret (FE) transducers in dependence on the amplitude of the high-voltage exciting pulse revealed a strongly nonlinear electromechanical response of the FE transmitter. This phenomenon is described by a linear increase of the inverse electromechanical transducer constant t_{33}^{(1)} of the PP FE film with an increase of the exciting electrical pulse amplitude. Enlargement of t_{33}^{(1)} by a factor of 4 was achieved by application of 3500 V exciting pulses. The electrostriction contribution to t_{33}^{(1)} can be attributed to the electrostatic force between electrodes and the Maxwell stress effect. The nonlinear electromechanical properties of the PP FE result in a strong increase of its air-coupled ultrasonic (ACUS) figure of merit ( FOM) under the high-voltage excitation, which exceeds results of the PP FE technological optimization. The FOM increase can be related to the increase of PP FE coupling factor and/or to the decrease of its acoustic impedance. A significant enhancement of the ACUS system transmission (12 dB) and signal-to-noise ratio (32 dB) was demonstrated by the increase of excitation voltage up to 3500 V. The nonlinear electromechanical properties of the PP FEs seem to be very important for their future applications.

  14. Ultrasonic Technology

    NASA Astrophysics Data System (ADS)

    Cho, Byoung-Kwan

    Ultrasonic has proven its merit as one of the most promising sensing methods for food quality evaluation due to its non-destructive, noninvasive, precise, rapid, and on-line potential. Ultrasonic is mechanical wave at frequencies above 20 kHz propagating by vibration of the particles in the medium and penetrating through optically opaque materials to provide internal or surface information of physical attributes, such as texture and structure. Ultrasonic non-destructive testing is a way of characterizing materials by transmitting ultrasonic waves into a material, and investigating the characteristics of the transmitted and/or reflected ultrasonic waves. For the purpose of quality measurement of materials, low-intensity ultrasonic with the power level of up to 1 W/cm2 has been used. The low-intensity ultrasonic doesn't cause physical or chemical changes in the properties of the specimen when it transmits through the material. However, high-intensity ultrasonic of the power range above 1 W/cm2 may produce physical/chemical disruption and alteration in the material through which the wave propagates. High-intensity ultrasonic is usually used in cleaning, promotion of chemical reactions, homogenization, etc

  15. Ultrasonic absortion in fatigued materials

    NASA Astrophysics Data System (ADS)

    Dugan, S.; Arnold, W.

    2013-01-01

    Non-destructive detection of fatigue damage, allowing an estimate of the residual life-time of components, could contribute to a safe and reliable operation of components and installations. Ultrasonic absorption, i.e. the internal friction, of a material increases with increasing fatigue or creep damage and there are many theories trying to explain the physics behind this phenomenon. Measurement of ultrasonic absorption directly on components could provide information on the degree of damage. A laser ultrasonic method, using laser-generated pulses and optical detection, was applied to study ultrasonic absorption in fatigue specimens of different metals. A characteristic behavior of the ultrasonic absorption coefficient with increasing levels of fatigue damage was found for the titanium alloy Ti-6Al-4V. Another aim of this study was to relate the absorption mechanisms to the behavior of ultrasonic absorption observed in metals with complex microstructure. To achieve this, different ultrasonic absorption mechanisms were analyzed with respect to experimental data. A thermoelastic effect related to the size and elasticity of the microstructure is discussed as the origin of the increased ultrasonic absorption.

  16. Nondestructive characterization of thermal barrier coating by noncontact laser ultrasonic technique

    NASA Astrophysics Data System (ADS)

    Zhao, Yang; Chen, Jianwei; Zhang, Zhenzhen

    2015-09-01

    We present the application of a laser ultrasonic technique in nondestructive characterization of the bonding layer (BL) in a thermal barrier coating (TBC). A physical mode of a multilayered medium is established to describe the propagation of a longitudinal wave generated by a laser in a TBC system. Furthermore, the theoretical analysis on the ultrasonic transmission in TBC is carried out in order to derive the expression of the BL transmission coefficient spectrum (TCS) which is used to determine the velocity of the longitudinal wave in the BL. We employ the inversion method combined with TCS to ascertain the attenuation coefficient of the BL. The experimental validations are performed with TBC specimens produced by an electron-beam physical vapor deposition method. In those experiments, a pulsed laser with a width of 10 ns is used to generate an ultrasonic signal while a two-wave mixing interferometer is created to receive the ultrasonic signals. By introducing the wavelet soft-threshold method that improves the signal-to-noise ratio, the laser ultrasonic testing results of TBC with an oxidation of 1 cycle, 10 cycles, and 100 cycles show that the attenuation coefficients of the BL become larger with an increase in the oxidation time, which is evident for the scanning electron microscopy observations, in which the thickness of the thermally grown oxide increases with oxidation time.

  17. A 13.56-mbps pulse delay modulation based transceiver for simultaneous near-field data and power transmission.

    PubMed

    Kiani, Mehdi; Ghovanloo, Maysam

    2015-02-01

    A fully-integrated near-field wireless transceiver has been presented for simultaneous data and power transmission across inductive links, which operates based on pulse delay modulation (PDM) technique. PDM is a low-power carrier-less modulation scheme that offers wide bandwidth along with robustness against strong power carrier interference, which makes it suitable for implantable neuroprosthetic devices, such as retinal implants. To transmit each bit, a pattern of narrow pulses are generated at the same frequency of the power carrier across the transmitter (Tx) data coil with specific time delays to initiate decaying ringing across the tuned receiver (Rx) data coil. This ringing shifts the zero-crossing times of the undesired power carrier interference on the Rx data coil, resulting in a phase shift between the signals across Rx power and data coils, from which the data bit stream can be recovered. A PDM transceiver prototype was fabricated in a 0.35- μm standard CMOS process, occupying 1.6 mm(2). The transceiver achieved a measured 13.56 Mbps data rate with a raw bit error rate (BER) of 4.3×10(-7) at 10 mm distance between figure-8 data coils, despite a signal-to-interference ratio (SIR) of -18.5 dB across the Rx data coil. At the same time, a class-D power amplifier, operating at 13.56 MHz, delivered 42 mW of regulated power across a separate pair of high-Q power coils, aligned with the data coils. The PDM data Tx and Rx power consumptions were 960 pJ/bit and 162 pJ/bit, respectively, at 1.8 V supply voltage. PMID:24760945

  18. Monitoring of Freeze-Thaw Cycles in Concrete Using Embedded Sensors and Ultrasonic Imaging

    PubMed Central

    Ranz, Javier; Aparicio, Sofía; Romero, Héctor; Casati, María Jesús; Molero, Miguel; González, Margarita

    2014-01-01

    This paper deals with the study of damage produced during freeze-thaw (F-T) cycles using two non-destructive measurement approaches—the first approach devoted to continuous monitoring using embedded sensors during the cycles, and the second one, performing ultrasonic imaging before and after the cycles. Both methodologies have been tested in two different types of concrete specimens, with and without air-entraining agents. Using the first measurement approach, the size and distribution of pores were estimated using a thermoporometrical model and continuous measurements of temperature and ultrasonic velocity along cycles. These estimates have been compared with the results obtained using mercury porosimetry testing. In the second approach, the damage due to F-T cycles has been evaluated by automated ultrasonic transmission and pulse-echo inspections made before and after the cycles. With these inspections the variations in the dimensions, velocity and attenuation caused by the accelerated F-T cycles were determined. PMID:24481231

  19. Time Reversal Beam Focusing of Ultrasonic Array Transducer on a Defect in a Two Layer Medium

    NASA Astrophysics Data System (ADS)

    Jeong, Hyunjo; Lee, Jeong-Sik; Lee, Chung-Hoon

    2010-02-01

    The ability of time reversal techniques to focus ultrasonic beams on the source location is important in many aspects of ultrasonic nondestructive evaluation. In this paper, we investigate the time reversal beam focusing of ultrasonic array sensors on a defect in layered media. Numerical modeling is performed using the commercially available software which employs a time domain finite difference method. Two different time reversal approaches are considered—the through transmission and the pulse-echo. Linear array sensors composed of N elements of line sources are used for signal reception/excitation, time reversal, and reemission in time reversal processes associated with the scattering source of a side-drilled hole located in the second layer of two layer structure. The simulation results demonstrate the time reversal focusing even with multiple reflections from the interface of layered structure. We examine the focusing resolution that is related to the propagation distance, the size of array sensor and the wavelength.

  20. Monitoring of freeze-thaw cycles in concrete using embedded sensors and ultrasonic imaging.

    PubMed

    Ranz, Javier; Aparicio, Sofía; Romero, Héctor; Casati, María Jesús; Molero, Miguel; González, Margarita

    2014-01-01

    This paper deals with the study of damage produced during freeze-thaw (F-T) cycles using two non-destructive measurement approaches-the first approach devoted to continuous monitoring using embedded sensors during the cycles, and the second one, performing ultrasonic imaging before and after the cycles. Both methodologies have been tested in two different types of concrete specimens, with and without air-entraining agents. Using the first measurement approach, the size and distribution of pores were estimated using a thermoporometrical model and continuous measurements of temperature and ultrasonic velocity along cycles. These estimates have been compared with the results obtained using mercury porosimetry testing. In the second approach, the damage due to F-T cycles has been evaluated by automated ultrasonic transmission and pulse-echo inspections made before and after the cycles. With these inspections the variations in the dimensions, velocity and attenuation caused by the accelerated F-T cycles were determined. PMID:24481231

  1. Proceedings of the IEEE 1986 ultrasonics symposium

    SciTech Connect

    Mc Avoy, B.R.

    1987-01-01

    This book presents the papers given at a conference on ultrasonic testing. Topics considered at the conference included the use of multiprocessors, the laser generation of acoustic waves, ultrasonic techniques in oil well logging, digital systems, piezoelectric devices, computerized tomography, Doppler tomography, pulse shaping techniques, blood flow, surface acoustic wave attenuation, sputtering, and microstructure.

  2. Improved Ultrasonic Transducer For Measuring Cryogenic Flow

    NASA Technical Reports Server (NTRS)

    Barkhoudarian, Sarkis

    1991-01-01

    Improved ultrasonic transducer used to measure flow of cryogenic fluid. Includes wedge made nonintrusive by machining it out of bulk material of duct carrying fluid. Skewed surfaces of wedge suppress standing waves, thus reducing ringing and increasing signal-to-noise ratio. Increases accuracy of measurements of times of arrival of ultrasonic pulses, from which times flow inferred.

  3. Single-channel 1.92 Tbit/s, Pol-Mux-64 QAM coherent Nyquist pulse transmission over 150 km with a spectral efficiency of 7.5 bit/s/Hz.

    PubMed

    Otuya, David Odeke; Kasai, Keisuke; Yoshida, Masato; Hirooka, Toshihiko; Nakazawa, Masataka

    2014-10-01

    Coherent Nyquist pulses have been used for optical time division multiplexed (OTDM) digital coherent transmission, and a single-channel 1.92 Tbit/s, Pol-Mux-64 QAM coherent Nyquist pulse transmission over 150 km is demonstrated. The ability to considerably reduce the spectral bandwidth of the data signal enabled us to increase the spectral efficiency from 3.2 bit/s/Hz to 7.5 bit/s/Hz when using a Gaussian pulse train. PMID:25321956

  4. Wire Crimp Connectors Verification using Ultrasonic Inspection

    NASA Technical Reports Server (NTRS)

    Cramer, K. Elliott; Perey, Daniel F.; Yost, William T.

    2007-01-01

    The development of a new ultrasonic measurement technique to quantitatively assess wire crimp connections is discussed. The amplitude change of a compressional ultrasonic wave propagating through the junction of a crimp connector and wire is shown to correlate with the results of a destructive pull test, which previously has been used to assess crimp wire junction quality. Various crimp junction pathologies (missing wire strands, incorrect wire gauge, incomplete wire insertion in connector) are ultrasonically tested, and their results are correlated with pull tests. Results show that the ultrasonic measurement technique consistently (as evidenced with pull-testing data) predicts good crimps when ultrasonic transmission is above a certain threshold amplitude level. A physics-based model, solved by finite element analysis, describes the compressional ultrasonic wave propagation through the junction during the crimping process. This model is in agreement within 6% of the ultrasonic measurements. A prototype instrument for applying the technique while wire crimps are installed is also presented.

  5. Ultrasonic propagation in gases at high temperatures

    NASA Technical Reports Server (NTRS)

    Carey, C.; Carnevale, E. H.; Lynworth, L. C.; Uva, S.

    1970-01-01

    Ultrasonic pulse method /1 to 3 MHz/ measures both sound speed and absorption in monatomic and polyatomic gases in a temperature range of 300 to 20000 degrees K at atmospheric pressure. Helium, nitrogen, oxygen, and argon are investigated.

  6. Effects of pressure-dependent segmental arterial compliance and postural changes on pulse wave transmission in an arterial model of the human upper limb.

    PubMed

    Xu, Ke; Butlin, Mark; Avolio, Alberto P

    2011-01-01

    With increasing interest in the effect of postural changes on arterial blood pressure and vascular properties, it is important to understand effects of pressure-dependent arterial compliance. This study investigates effects of pressure-dependent compliance on pulse wave velocity (PWVar), pressure wave shape, and transmission characteristics in an arterial model of the human arm from heart to radial artery from supine to standing. Estimated central pressure waveform was used as the input for the model, calculated using a validated transfer function (SphygmoCor, AtCor Medical) from recorded radial pulses in 10 healthy male subjects (53.8 ± 7.9 years) during 0, 30, 60 and 90 degree head-up tilt. A 5-segment linear model was optimized using estimated central and recorded radial arterial pulse; each segment represented by an equivalent inductance, resistance and capacitance (compliance (C)) Pressure-dependent compliance (C(P)=a · e(b · P) was added to develop a nonlinear model, and the radial pulse calculated. Comparison of the radial pulse calculated by the linear and nonlinear models showed no statistical difference in systolic, diastolic, mean, and pulse pressure in any position of tilt. However, waveform shape was increasingly divergent at higher angles of tilt (RMS error 2.3 ± 1.2 mmHg supine, 6.5 ± 3.0 mmHg standing) as was PWVar (0% increase from supine to standing in the linear model, 16.7% increase in nonlinear model). Fourier analysis demonstrated peak amplitude of transmission being at higher frequencies and phase delay being lower in the nonlinear model relative to the linear model. Pressure-dependent arterial compliance, whilst having no effect on peak values of pressure, has significant effects on waveform shape and transmission speed, especially with a more upright position. PMID:22255815

  7. Mathematical Constraints on the Use of Transmission Line Models for Simulating Initial Breakdown Pulses in Lightning Discharges

    NASA Astrophysics Data System (ADS)

    da Silva, C. L.; Merrill, R. A.; Pasko, V. P.

    2015-12-01

    A significant portion of the in-cloud lightning development is observed as a series of initial breakdown pulses (IBPs) that are characterized by an abrupt change in the electric field at a remote sensor. Recent experimental and theoretical studies have attributed this process to the stepwise elongation of an initial lightning leader inside the thunderstorm [da Silva and Pasko, JGR, 120, 4989-5009, 2015, and references therein]. Attempts to visually observe these events are hampered due to the fact that clouds are opaque to optical radiation. Due to this reason, throughout the last decade, a number of researchers have used the so-called transmission line models (also commonly referred to as engineering models), widely employed for return stroke simulations, to simulate the waveshapes of IBPs, and also of narrow bipolar events. The transmission line (TL) model approach is to prescribe the source current dynamics in a certain manner to match the measured E-field change waveform, with the purpose of retrieving key information about the source, such as its height, peak current, size, speed of charge motion, etc. Although the TL matching method is not necessarily physics-driven, the estimated source characteristics can give insights on the dominant length- and time-scales, as well as, on the energetics of the source. This contributes to better understanding of the environment where the onset and early stages of lightning development takes place.In the present work, we use numerical modeling to constrain the number of source parameters that can be confidently inferred from the observed far-field IBP waveforms. We compare different modified TL models (i.e., with different attenuation behaviors) to show that they tend to produce similar waveforms in conditions where the channel is short. We also demonstrate that it is impossible to simultaneously retrieve the speed of source current propagation and channel length from an observed IBP waveform, in contrast to what has been

  8. Ultrasonic Maintenance

    NASA Technical Reports Server (NTRS)

    1991-01-01

    The Ultraprobe 2000, manufactured by UE Systems, Inc., Elmsford, NY, is a hand-held ultrasonic system that detects indications of bearing failure by analyzing changes in amplitude. It employs the technology of a prototype ultrasonic bearing-failure monitoring system developed by Mechanical Technology, Inc., Latham, New York and Marshall Space Flight Center (which was based on research into Skylab's gyroscope bearings). Bearings on the verge of failure send ultrasonic signals indicating their deterioration; the Ultraprobe changes these to audible signals. The operator hears the signals and gages their intensity with a meter in the unit.

  9. Imaging Inhomogeneities From Dry-Coupled Ultrasonic Scans

    NASA Technical Reports Server (NTRS)

    Roth, Don J.

    1995-01-01

    Method of imaging spatial distribution of selected physical properties and microstructure of specimen of material based on dry-coupled contact ultrasonic pulse/echo scanning. Ultrasonic transducer scanned across top surface of specimen. At each of many positions on two-dimensional grid on top surface, ultrasonic pulse/echo measurements taken and processed. Offers rapid, nondestructive alternative to destructive metallographic sectioning to obtain picture of inhomogeneity of specimen.

  10. Synchronized delivery of Er:YAG-laser pulses into water studied by a laser beam transmission probe for enhanced endodontic treatment

    NASA Astrophysics Data System (ADS)

    Gregorčič, P.; Lukač, N.; Možina, J.; Jezeršek, M.

    2016-04-01

    We examine the effects of the synchronized delivery of multiple Er:YAG-laser pulses during vapor-bubble oscillations into water. For this purpose, we used a laser beam transmission probe that enables monitoring of the bubble's dynamics from a single shot. To overcome the main drawbacks of this technique, we propose and develop an appropriate and robust calibration by simultaneous employment of shadow photography. By using the developed experimental method, we show that the resonance effect is obtained when the second laser pulse is delivered at the end or slightly after the first bubble's collapse. In this case, the resonance effect increases the mechanical energy of the secondary bubble's oscillations and prolongs their duration. The presented laser method for synchronized delivery of Er:YAG-laser pulses during bubble oscillations has great potential for further improvement of laser endodontic treatment, especially upon their safety and efficiency.

  11. Techniques for enhancing laser ultrasonic nondestructive evaluation

    SciTech Connect

    Candy, J; Chinn, D; Huber, R; Spicer, J; Thomas, G

    1999-02-16

    Ultrasonic nondestructive evaluation is an extremely powerful tool for characterizing materials and detecting defects. A majority of the ultrasonic nondestructive evaluation is performed with piezoelectric transducers that generate and detect high frequency acoustic energy. The liquid needed to couple the high frequency acoustic energy from the piezoelectric transducers restricts the applicability of ultrasonics. For example, traditional ultrasonics cannot evaluate parts at elevated temperatures or components that would be damaged by contact with a fluid. They are developing a technology that remotely generates and detects the ultrasonic pulses with lasers and consequently there is no requirement for liquids. Thus the research in laser-based ultrasound allows them to solve inspection problems with ultrasonics that could not be done before. This technology has wide application in many Lawrence Livermore National Laboratory programs, especially when remote and/or non-contact sensing is necessary.

  12. Ultrasonic method for measuring water holdup of low velocity and high-water-cut oil-water two-phase flow

    NASA Astrophysics Data System (ADS)

    Zhao, An; Han, Yun-Feng; Ren, Ying-Yu; Zhai, Lu-Sheng; in, Ning-De

    2016-03-01

    Oil reservoirs with low permeability and porosity that are in the middle and late exploitation periods in China's onshore oil fields are mostly in the high-water-cut production stage. This stage is associated with severely non-uniform local-velocity flow profiles and dispersed-phase concentration (of oil droplets) in oil-water two-phase flow, which makes it difficult to measure water holdup in oil wells. In this study, we use an ultrasonic method based on a transmission-type sensor in oil-water two-phase flow to measure water holdup in low-velocity and high water-cut conditions. First, we optimize the excitation frequency of the ultrasonic sensor by calculating the sensitivity of the ultrasonic field using the finite element method for multiphysics coupling. Then we calculate the change trend of sound pressure level attenuation ratio with the increase in oil holdup to verify the feasibility of the employed diameter for the ultrasonic sensor. Based on the results, we then investigate the effects of oil-droplet diameter and distribution on the ultrasonic field. To further understand the measurement characteristics of the ultrasonic sensor, we perform a flow loop test on vertical upward oil-water two-phase flow and measure the responses of the optimized ultrasonic sensor. The results show that the ultrasonic sensor yields poor resolution for a dispersed oil slug in water flow (D OS/W flow), but the resolution is favorable for dispersed oil in water flow (D O/W flow) and very fine dispersed oil in water flow (VFD O/W flow). This research demonstrates the potential application of a pulsed-transmission ultrasonic method for measuring the fraction of individual components in oil-water two-phase flow with a low mixture velocity and high water cut.

  13. Tailoring ultrasonic beams with optoacoustic holography

    NASA Astrophysics Data System (ADS)

    Meyer, Alex; Gspan, Stefan J.; Bernet, Stefan; Ritsch-Marte, Monika

    2003-06-01

    A combination of laser-induced ultrasound generation and ultrasonic holography for spatial control of the generated ultrasonic pulse is presented. Ultrasound is produced by absorption of laser pulses at an absorbing layer in a water tank via the optoacoustic effect. In order to produce a defined ultrasonic frequency in the MHz range, the laser pulses are harmonically time-modulated using an acousto-optic modulator (AOM). Additionally, the laser intensity is spatially controlled. This is realized with a high resolution liquid crystal spatial light modulator (LCD). A computer generated pattern is displayed at the LCD and projected by the expanded laser beam to an absorptive layer in the water tank. As a result, the emitted ultrasonic wave emerges in a predetermined way, which is an acoustical analogue to the effect of a "diffractive optical element" in laser optics. The flexible method of optical ultrasound generation and diffractive steering promises new applications in medical and technical ultrasound diagnostics.

  14. An Ultrasonic-Adaptive Beamforming Method and Its Application for Trans-skull Imaging of Certain Types of Head Injuries; Part I: Transmission Mode.

    PubMed

    Shapoori, Kiyanoosh; Sadler, Jeff; Wydra, Adrian; Malyarenko, Eugene V; Sinclair, Anthony N; Maev, Roman Gr

    2015-05-01

    A new adaptive beamforming algorithm for imaging via small-aperture 1-D ultrasonic-phased arrays through composite layered structures is reported. Such structures cause acoustic phase aberration and wave refraction at undulating interfaces and can lead to significant distortion of an ultrasonic field pattern produced by conventional beamforming techniques. This distortion takes the form of defocusing the ultrasonic field transmitted through the barrier and causes loss of resolution and overall degradation of image quality. To compensate for the phase aberration and the refractional effects, we developed and examined an adaptive beamforming algorithm for small-aperture linear-phased arrays. After accurately assessing the barrier's local geometry and sound speed, the method calculates a new timing scheme to refocus the distorted beam at its original location. As a tentative application, implementation of this method for trans-skull imaging of certain types of head injuries through human skull is discussed. Simulation and laboratory results of applying the method on skull-mimicking phantoms are presented. Correction of up to 2.5 cm focal point displacement at up to 10 cm depth under our skull phantom is demonstrated. Quantitative assessment of the method in a variety of temporal focusing scenarios is also reported. Overall temporal deviation on the order of a few nanoseconds was observed between the simulated and experimental results. The single-point adaptive focusing results demonstrate strong potential of our approach for diagnostic imaging through intact human skull. The algorithms were implemented on an ultrasound advanced open-platform controlling 64 active elements on a 128-element phased array. PMID:25423646

  15. System and technique for ultrasonic determination of degree of cooking

    DOEpatents

    Bond, Leonard J.; Diaz, Aaron A.; Judd, Kayte M.; Pappas, Richard A.; Cliff, William C.; Pfund, David M.; Morgen, Gerald P.

    2007-03-20

    A method and apparatus are described for determining the doneness of food during a cooking process. Ultrasonic signal are passed through the food during cooking. The change in transmission characteristics of the ultrasonic signal during the cooking process is measured to determine the point at which the food has been cooked to the proper level. In one aspect, a heated fluid cooks the food, and the transmission characteristics along a fluid-only ultrasonic path provides a reference for comparison with the transmission characteristics for a food-fluid ultrasonic path.

  16. Characterization of Transducer Performance and Narrowband Transient Ultrasonic Fields in Metals by Rayleigh-Sommerfeld Backpropagation of Compression Acoustic Waves Measured with Double-Pulsed Tv Holography

    NASA Astrophysics Data System (ADS)

    Trillo, Cristina; Doval, Ángel F.; Fernández, José L.; Rodríguez-Gómez, Pablo; López-Vázquez, J. Carlos

    2014-10-01

    This article presents a method aimed at the characterization of the narrowband transient acoustic field radiated by an ultrasonic plane transducer into a homogeneous, isotropic and optically opaque prismatic solid, and the assessment of the performance of the acoustic source. The method relies on a previous technique based on the full-field optical measurement of an acoustic wavepacket at the surface of a solid and its subsequent numerical backpropagation within the material. The experimental results show that quantitative transversal and axial profiles of the complex amplitude of the beam can be obtained at any plane between the measurement and excitation surfaces. The reconstruction of the acoustic field at the transducer face, carried out on a defective transducer model, shows that the method could also be suitable for the nondestructive testing of the performance of ultrasonic sources. In all cases, the measurements were performed with the transducer working under realistic loading conditions.

  17. Pulse based sensor networking using mechanical waves through metal substrates

    NASA Astrophysics Data System (ADS)

    Lorenz, S.; Dong, B.; Huo, Q.; Tomlinson, W. J.; Biswas, S.

    2013-05-01

    This paper presents a novel wireless sensor networking technique using ultrasonic signal as the carrier wave for binary data exchange. Using the properties of lamb wave propagation through metal substrates, the proposed network structure can be used for runtime transport of structural fault information to ultrasound access points. Primary applications of the proposed sensor networking technique will include conveying fault information on an aircraft wing or on a bridge to an ultrasonic access point using ultrasonic wave through the structure itself (i.e. wing or bridge). Once a fault event has been detected, a mechanical pulse is forwarded to the access node using shortest path multi-hop ultrasonic pulse routing. The advantages of mechanical waves over traditional radio transmission using pulses are the following: First, unlike radio frequency, surface acoustic waves are not detectable outside the medium, which increases the inherent security for sensitive environments in respect to tapping. Second, event detection can be represented by the injection of a single mechanical pulse at a specific temporal position, whereas radio messages usually take several bits. The contributions of this paper are: 1) Development of a transceiver for transmitting/receiving ultrasound pulses with a pulse loss rate below 2·10-5 and false positive rate with an upper bound of 2·10-4. 2) A novel one-hop distance estimation based on the properties of lamb wave propagation with an accuracy of above 80%. 3) Implementation of a wireless sensor network using mechanical wave propagation for event detection on a 2024 aluminum alloy commonly used for aircraft skin construction.

  18. Ultrasonic Polishing

    NASA Technical Reports Server (NTRS)

    Gilmore, Randy

    1993-01-01

    The ultrasonic polishing process makes use of the high-frequency (ultrasonic) vibrations of an abradable tool which automatically conforms to the work piece and an abrasive slurry to finish surfaces and edges on complex, highly detailed, close tolerance cavities in materials from beryllium copper to carbide. Applications range from critical deburring of guidance system components to removing EDM recast layers from aircraft engine components to polishing molds for forming carbide cutting tool inserts or injection molding plastics. A variety of materials including tool steels, carbides, and even ceramics can be successfully processed. Since the abradable tool automatically conforms to the work piece geometry, the ultrasonic finishing method described offers a number of important benefits in finishing components with complex geometries.

  19. Ultrasonic neuromodulation

    NASA Astrophysics Data System (ADS)

    Naor, Omer; Krupa, Steve; Shoham, Shy

    2016-06-01

    Ultrasonic waves can be non-invasively steered and focused into mm-scale regions across the human body and brain, and their application in generating controlled artificial modulation of neuronal activity could therefore potentially have profound implications for neural science and engineering. Ultrasonic neuro-modulation phenomena were experimentally observed and studied for nearly a century, with recent discoveries on direct neural excitation and suppression sparking a new wave of investigations in models ranging from rodents to humans. In this paper we review the physics, engineering and scientific aspects of ultrasonic fields, their control in both space and time, and their effect on neuronal activity, including a survey of both the field’s foundational history and of recent findings. We describe key constraints encountered in this field, as well as key engineering systems developed to surmount them. In closing, the state of the art is discussed, with an emphasis on emerging research and clinical directions.

  20. Ultrasonic neuromodulation.

    PubMed

    Naor, Omer; Krupa, Steve; Shoham, Shy

    2016-06-01

    Ultrasonic waves can be non-invasively steered and focused into mm-scale regions across the human body and brain, and their application in generating controlled artificial modulation of neuronal activity could therefore potentially have profound implications for neural science and engineering. Ultrasonic neuro-modulation phenomena were experimentally observed and studied for nearly a century, with recent discoveries on direct neural excitation and suppression sparking a new wave of investigations in models ranging from rodents to humans. In this paper we review the physics, engineering and scientific aspects of ultrasonic fields, their control in both space and time, and their effect on neuronal activity, including a survey of both the field's foundational history and of recent findings. We describe key constraints encountered in this field, as well as key engineering systems developed to surmount them. In closing, the state of the art is discussed, with an emphasis on emerging research and clinical directions. PMID:27153566

  1. Ultrasonic angioplasty

    NASA Astrophysics Data System (ADS)

    Siegel, Robert J.

    1990-08-01

    Over the past 3 years we have developed a percutaneous ultrasonic angioplasty device and recently applied it in human peripheral arteries. This paper describes some of the background preceding the development of intravascular ultrasound for arterial recanalization. The chronology of our development of ultrasonic angioplasty is discussed from in vitro studies on atherosclerotic plaque to in vivo studies in canine models with differing types of arterial occlusions (thrombotic fibrotic calcific-atherosclerotic) and to initial human application. SPIE Vol. 1321 Modern Technologies Applied to Medical Practice (1989) / 69

  2. Ultrasonic Inspection

    NASA Technical Reports Server (NTRS)

    1976-01-01

    Automation Industries Inc. has had more than $2 million in contracts to produce innovative equipment for the Apollo program. When Marshall Space Flight Center sought a fast nondestructive way to inspect butt welds in aluminum alloys for spacecraft, the company developed a reliable ultrasonic device using multiple transducers called "delta manipulators" which detect lack of weld penetration not readily seen in radiograph automation. Industry soon adapted the ultrasonic equipment to a unique rail inspection device that saves countless man hours. Device is contained in self propelled railroad cars produced and operated by the company to check old track welds for deterioration.

  3. Ultrasonic generator and detector using an optical mask having a grating for launching a plurality of spatially distributed, time varying strain pulses in a sample

    DOEpatents

    Maris, Humphrey J.

    2002-01-01

    A method and a system are disclosed for determining at least one characteristic of a sample that contains a substrate and at least one film disposed on or over a surface of the substrate. The method includes a first step of placing a mask over a free surface of the at least one film, where the mask has a top surface and a bottom surface that is placed adjacent to the free surface of the film. The bottom surface of the mask has formed therein or thereon a plurality of features for forming at least one grating. A next step directs optical pump pulses through the mask to the free surface of the film, where individual ones of the pump pulses are followed by at least one optical probe pulse. The pump pulses are spatially distributed by the grating for launching a plurality of spatially distributed, time varying strain pulses within the film, which cause a detectable change in optical constants of the film. A next step detects a reflected or a transmitted portion of the probe pulses, which are also spatially distributed by the grating. A next step measures a change in at least one characteristic of at least one of reflected or transmitted probe pulses due to the change in optical constants, and a further step determines the at least one characteristic of the sample from the measured change in the at least one characteristic of the probe pulses. An optical mask is also disclosed herein, and forms a part of these teachings.

  4. Ultrasonic generator and detector using an optical mask having a grating for launching a plurality of spatially distributed, time varying strain pulses in a sample

    DOEpatents

    Maris, Humphrey J.

    2003-01-01

    A method and a system are disclosed for determining at least one characteristic of a sample that contains a substrate and at least one film disposed on or over a surface of the substrate. The method includes a first step of placing a mask over a free surface of the at least one film, where the mask has a top surface and a bottom surface that is placed adjacent to the free surface of the film. The bottom surface of the mask has formed therein or thereon a plurality of features for forming at least one grating. A next step directs optical pump pulses through the mask to the free surface of the film, where individual ones of the pump pulses are followed by at least one optical probe pulse. The pump pulses are spatially distributed by the grating for launching a plurality of spatially distributed, time varying strain pulses within the film, which cause a detectable change in optical constants of the film. A next step detects a reflected or a transmitted portion of the probe pulses, which are also spatially distributed by the grating. A next step measures a change in at least one characteristic of at least one of reflected or transmitted probe pulses due to the change in optical constants, and a further step determines the at least one characteristic of the sample from the measured change in the at least one characteristic of the probe pulses. An optical mask is also disclosed herein, and forms a part of these teachings.

  5. Asymmetric Ultrasonic Pulse Radiation Using Electromagnetic-Induction Transducer and PZT(Pb(Zr-Ti)O3) Transducer with Wave Synthesis Method

    NASA Astrophysics Data System (ADS)

    Endoh, Nobuyuki; Yamamoto, Koji

    1993-05-01

    In medical applications, especially in urology, we use a fragmentation calculus technique with shock waves. This technique is very profitable because of no abdominal surgery for a human being. Large negative sound amplitude pulses, however, can cause problems such as internal hemorrhage or pain in the human body. The final goal of this study is to develop a means to project an intense positive unipolar pulse without negative sound pressure. We improved a composite transducer consisting of an electromagnetic-induction-type (EMI) transducer and PZT (Pb(Zr-Ti)O3) transducers. An EMI transducer consisting of a metal coil and vibration membrane can project intense sound pulses into water. In order to suppress its negative sound pressure, we project a compensation pulse with PZT transducers using an inverse filtering method. An asymmetric pulse whose P+ to P- amplitude ratio was very high was projected in water.

  6. Studies on Laser Generated Ultrasonic Waves in Inconel Super Alloy

    SciTech Connect

    Pramila, T.; Shukla, Anita; Raghuram, V.

    2010-05-28

    This paper deals with the generation, characterization and analysis of ultrasonic waves generated in a thick stepped sample of inconel super alloy using Laser Based Ultrasonic Technique. Nd-YAG pulsed laser is used for ultrasonic generation while He-Ne laser is used for heterodyne detection. Ultrasonic signals are analyzed using Fourier and wavelet transforms. Here the identification and estimation of velocity of pressure waves is presented. The mechanism of pressure wave generation is discussed in brief. Laser ultrasonics studies of inconel are being reported for the first time.

  7. Out-of-plane ultrasonic velocity measurement

    DOEpatents

    Hall, M.S.; Brodeur, P.H.; Jackson, T.G.

    1998-07-14

    A method for improving the accuracy of measuring the velocity and time of flight of ultrasonic signals through moving web-like materials such as paper, paperboard and the like, includes a pair of ultrasonic transducers disposed on opposing sides of a moving web-like material. In order to provide acoustical coupling between the transducers and the web-like material, the transducers are disposed in fluid-filled wheels. Errors due to variances in the wheel thicknesses about their circumference which can affect time of flight measurements and ultimately the mechanical property being tested are compensated by averaging the ultrasonic signals for a predetermined number of revolutions. The invention further includes a method for compensating for errors resulting from the digitization of the ultrasonic signals. More particularly, the invention includes a method for eliminating errors known as trigger jitter inherent with digitizing oscilloscopes used to digitize the signals for manipulation by a digital computer. In particular, rather than cross-correlate ultrasonic signals taken during different sample periods as is known in the art in order to determine the time of flight of the ultrasonic signal through the moving web, a pulse echo box is provided to enable cross-correlation of predetermined transmitted ultrasonic signals with predetermined reflected ultrasonic or echo signals during the sample period. By cross-correlating ultrasonic signals in the same sample period, the error associated with trigger jitter is eliminated. 20 figs.

  8. Out-of-plane ultrasonic velocity measurement

    DOEpatents

    Hall, Maclin S.; Brodeur, Pierre H.; Jackson, Theodore G.

    1998-01-01

    A method for improving the accuracy of measuring the velocity and time of flight of ultrasonic signals through moving web-like materials such as paper, paperboard and the like, includes a pair of ultrasonic transducers disposed on opposing sides of a moving web-like material. In order to provide acoustical coupling between the transducers and the web-like material, the transducers are disposed in fluid-filled wheels. Errors due to variances in the wheel thicknesses about their circumference which can affect time of flight measurements and ultimately the mechanical property being tested are compensated by averaging the ultrasonic signals for a predetermined number of revolutions. The invention further includes a method for compensating for errors resulting from the digitization of the ultrasonic signals. More particularly, the invention includes a method for eliminating errors known as trigger jitter inherent with digitizing oscilloscopes used to digitize the signals for manipulation by a digital computer. In particular, rather than cross-correlate ultrasonic signals taken during different sample periods as is known in the art in order to determine the time of flight of the ultrasonic signal through the moving web, a pulse echo box is provided to enable cross-correlation of predetermined transmitted ultrasonic signals with predetermined reflected ultrasonic or echo signals during the sample period. By cross-correlating ultrasonic signals in the same sample period, the error associated with trigger jitter is eliminated.

  9. Beam transmission of single high-power 0.248 micron and 1.06 micron laser pulses through a vacusol

    NASA Astrophysics Data System (ADS)

    White, John R.; Rice, James E.; Kremens, Robert L.; Lacy, Robert A.; Amimoto, Sherwin T.

    1989-06-01

    The interaction between high-power laser radiation and solid particles dispersed in vacuum (a 'vacusol') is studied. In the case of vacusols, as compared to aerosols, the attenuation of a high-power laser beam deviates from the low-intensity transmission of the cloud only if the opaque portion of the plasma sheath ablated from each particles is much larger than the size of the particle or if the laser pulse is energetic enough to vaporize a significant fraction of the particles. Consideration is given to the phenomena which occur when various particle sizes, particle compositions, laser intensities, wavelengths, and pulsewidths are used.

  10. Transmission and full-band coherent detection of polarization-multiplexed all-optical Nyquist signals generated by Sinc-shaped Nyquist pulses.

    PubMed

    Zhang, Junwen; Yu, Jianjun; Chi, Nan

    2015-01-01

    All optical method is considered as a promising technique for high symbol rate Nyquist signal generation, which has attracted a lot of research interests for high spectral-efficiency and high-capacity optical communication system. In this paper, we extend our previous work and report the fully experimental demonstration of polarization-division multiplexed (PDM) all-optical Nyquist signal generation based on Sinc-shaped Nyquist pulse with advanced modulation formats, fiber-transmission and single-receiver full-band coherent detection. Using this scheme, we have successfully demonstrated the generation, fiber transmission and single-receiver full-band coherent detection of all-optical Nyquist PDM-QPSK and PDM-16QAM signals up to 125-GBaud. 1-Tb/s single-carrier PDM-16QAM signal generation and full-band coherent detection is realized, which shows the advantage and feasibility of the single-carrier all-optical Nyquist signals. PMID:26323238

  11. Simplified flexible-PON upstream transmission using pulse position modulation at ONU and DSP-enabled soft-combining at OLT for adaptive link budgets.

    PubMed

    Liu, Xiang; Effenberger, Frank; Chand, Naresh

    2015-03-01

    We demonstrate a flexible modulation and detection scheme for upstream transmission in passive optical networks using pulse position modulation at optical network unit, facilitating burst-mode detection with automatic decision threshold tracking, and DSP-enabled soft-combining at optical line terminal. Adaptive receiver sensitivities of -33.1 dBm, -36.6 dBm and -38.3 dBm at a bit error ratio of 10(-4) are respectively achieved for 2.5 Gb/s, 1.25 Gb/s and 625 Mb/s after transmission over a 20-km standard single-mode fiber without any optical amplification. PMID:25836897

  12. Transmission and full-band coherent detection of polarization-multiplexed all-optical Nyquist signals generated by Sinc-shaped Nyquist pulses

    PubMed Central

    Zhang, Junwen; Yu, Jianjun; Chi, Nan

    2015-01-01

    All optical method is considered as a promising technique for high symbol rate Nyquist signal generation, which has attracted a lot of research interests for high spectral-efficiency and high-capacity optical communication system. In this paper, we extend our previous work and report the fully experimental demonstration of polarization-division multiplexed (PDM) all-optical Nyquist signal generation based on Sinc-shaped Nyquist pulse with advanced modulation formats, fiber-transmission and single-receiver full-band coherent detection. Using this scheme, we have successfully demonstrated the generation, fiber transmission and single-receiver full-band coherent detection of all-optical Nyquist PDM-QPSK and PDM-16QAM signals up to 125-GBaud. 1-Tb/s single-carrier PDM-16QAM signal generation and full-band coherent detection is realized, which shows the advantage and feasibility of the single-carrier all-optical Nyquist signals. PMID:26323238

  13. Transmission and full-band coherent detection of polarization-multiplexed all-optical Nyquist signals generated by Sinc-shaped Nyquist pulses

    NASA Astrophysics Data System (ADS)

    Zhang, Junwen; Yu, Jianjun; Chi, Nan

    2015-09-01

    All optical method is considered as a promising technique for high symbol rate Nyquist signal generation, which has attracted a lot of research interests for high spectral-efficiency and high-capacity optical communication system. In this paper, we extend our previous work and report the fully experimental demonstration of polarization-division multiplexed (PDM) all-optical Nyquist signal generation based on Sinc-shaped Nyquist pulse with advanced modulation formats, fiber-transmission and single-receiver full-band coherent detection. Using this scheme, we have successfully demonstrated the generation, fiber transmission and single-receiver full-band coherent detection of all-optical Nyquist PDM-QPSK and PDM-16QAM signals up to 125-GBaud. 1-Tb/s single-carrier PDM-16QAM signal generation and full-band coherent detection is realized, which shows the advantage and feasibility of the single-carrier all-optical Nyquist signals.

  14. Femtosecond measurements of near-infrared pulse induced mid-infrared transmission modulation of quantum cascade lasers

    SciTech Connect

    Cai, Hong; Liu, Sheng; Lalanne, Elaine; Guo, Dingkai; Chen, Xing; Choa, Fow-Sen; Wang, Xiaojun; Johnson, Anthony M.

    2014-05-26

    We temporally resolved the ultrafast mid-infrared transmission modulation of quantum cascade lasers (QCLs) using a near-infrared pump/mid-infrared probe technique at room temperature. Two different femtosecond wavelength pumps were used with photon energy above and below the quantum well (QW) bandgap. The shorter wavelength pump modulates the mid-infrared probe transmission through interband transition assisted mechanisms, resulting in a high transmission modulation depth and several nanoseconds recovery lifetime. In contrast, pumping with a photon energy below the QW bandgap induces a smaller transmission modulation depth but much faster (several picoseconds) recovery lifetime, attributed to intersubband transition assisted mechanisms. The latter ultrafast modulation (>60 GHz) could provide a potential way to realize fast QCL based free space optical communication.

  15. Ultrasonic colour flow imaging.

    PubMed

    Wells, P N

    1994-12-01

    Real-time ultrasonic colour flow imaging, which was first demonstrated to be feasible only about a decade ago, has come into widespread clinical use. Ultrasound is scattered by ensembles of red blood cells. The ultrasonic frequency that gives the best signal-to-noise ratio for backscattering from blood depends on the required penetration. The frequency of ultrasound backscattered from flowing blood is shifted by the Doppler effect. The direction of flow can be determined by phase quadrature detection, and range selectivity can be provided by pulse-echo time-delay measurements. The Doppler frequency spectrum can be determined by Fourier analysis. Early two- and three-dimensional flow-imaging systems used slow manual scanning; velocity colour coding was introduced. Real-time colour flow imaging first became feasible when autocorrelation detection was used to extract the Doppler signal. Time-domain processing, which is a broad-band technique, was also soon shown to be practicable, for analysing both radio-frequency pulse-echo wavetrains and two-dimensional image speckle. Frequency- and time-domain processing both require effective cancellation of stationary echoes. The time-domain approach seems to have advantages in relation to both aliasing and the effects of attenuation in overlying tissues. Colour-coding schemes that can be interpreted without the need to refer to keys have been adopted, for both velocity and flow disturbance. Colour coding according to signal power has also been reintroduced. Three-dimensional display has been demonstrated. In interpreting colour flow images, it is important to understand the functions of critical system controls and the origins of artifacts. Various strategies can be adopted to increase the image frame rate. The problems of performance measurement and safety need to be kept under review. There are numerous opportunities for further development of ultrasonic colour flow imaging, including improvements in system design, methods of

  16. Control of transmission of right circularly polarized laser light in overdense plasma by applied magnetic field pulses.

    PubMed

    Ma, Guangjin; Yu, Wei; Yu, M Y; Luan, Shixia; Wu, Dong

    2016-05-01

    The effect of a transient magnetic field on right-hand circularly polarized (RHCP) laser light propagation in overcritical-density plasma is investigated. When the electron gyrofrequency is larger than the wave frequency, RHCP light can propagate along the external magnetic field in an overcritical density plasma without resonance or cutoff. However, when the magnetic field falls to below the cyclotron resonance point, the propagating laser pulse will be truncated and the local plasma electrons resonantly heated. Particle-in-cell simulation shows that when applied to a thin slab, the process can produce intense two-cycle light pulses as well as long-lasting self-magnetic fields. PMID:27300997

  17. Control of transmission of right circularly polarized laser light in overdense plasma by applied magnetic field pulses

    NASA Astrophysics Data System (ADS)

    Ma, Guangjin; Yu, Wei; Yu, M. Y.; Luan, Shixia; Wu, Dong

    2016-05-01

    The effect of a transient magnetic field on right-hand circularly polarized (RHCP) laser light propagation in overcritical-density plasma is investigated. When the electron gyrofrequency is larger than the wave frequency, RHCP light can propagate along the external magnetic field in an overcritical density plasma without resonance or cutoff. However, when the magnetic field falls to below the cyclotron resonance point, the propagating laser pulse will be truncated and the local plasma electrons resonantly heated. Particle-in-cell simulation shows that when applied to a thin slab, the process can produce intense two-cycle light pulses as well as long-lasting self-magnetic fields.

  18. Ultrasonic measurement of milk coagulation time

    NASA Astrophysics Data System (ADS)

    Bakkali, F.; Moudden, A.; Faiz, B.; Amghar, A.; Maze, G.; Montero de Espinosa, F.; Akhnak, M.

    2001-12-01

    Using a pulse reflection technique an ultrasonic system has been developed to monitor in situ the coagulation process of rennetted milk. The velocity and attenuation of ultrasonic waves through coagulating milk were continuously monitored. The observed changes in ultrasonic velocity during coagulation were used to predict the coagulation time. The coagulation time is indicative of the transition from the enzymatic phase to the physicochemical phase. The determination of coagulation time has a decisive role in determining the qualities of the end product in cheesemaking.

  19. Ultrasonic propulsion of kidney stones

    PubMed Central

    May, Philip C.; Bailey, Michael R.; Harper, Jonathan D.

    2016-01-01

    Purpose of review Ultrasonic propulsion is a novel technique that uses short bursts of focused ultrasonic pulses to reposition stones transcutaneously within the renal collecting system and ureter. The purpose of this review is to discuss the initial testing of effectiveness and safety, directions for refinement of technique and technology, and opinions on clinical application. Recent findings Preclinical studies with a range of probes, interfaces, and outputs have demonstrated feasibility and consistent safety of ultrasonic propulsion with room for increased outputs and refinement toward specific applications. Ultrasonic propulsion was used painlessly and without adverse events to reposition stones in 14 of 15 human study participants without restrictions on patient size, stone size, or stone location. The initial feasibility study showed applicability in a range of clinically relevant situations, including facilitating passage of residual fragments following ureteroscopy or shock wave lithotripsy, moving a large stone at the UPJ with relief of pain, and differentiating large stones from a collection of small fragments. Summary Ultrasonic propulsion shows promise as an office-based system for transcutaneously repositioning kidney stones. Potential applications include facilitating expulsion of residual fragments following ureteroscopy or shock wave lithotripsy, repositioning stones prior to treatment, and repositioning obstructing UPJ stones into the kidney to alleviate acute renal colic. PMID:26845428

  20. Graphene electrostatic microphone and ultrasonic radio.

    PubMed

    Zhou, Qin; Zheng, Jinglin; Onishi, Seita; Crommie, M F; Zettl, Alex K

    2015-07-21

    We present a graphene-based wideband microphone and a related ultrasonic radio that can be used for wireless communication. It is shown that graphene-based acoustic transmitters and receivers have a wide bandwidth, from the audible region (20∼20 kHz) to the ultrasonic region (20 kHz to at least 0.5 MHz). Using the graphene-based components, we demonstrate efficient high-fidelity information transmission using an ultrasonic band centered at 0.3 MHz. The graphene-based microphone is also shown to be capable of directly receiving ultrasound signals generated by bats in the field, and the ultrasonic radio, coupled to electromagnetic (EM) radio, is shown to function as a high-accuracy rangefinder. The ultrasonic radio could serve as a useful addition to wireless communication technology where the propagation of EM waves is difficult. PMID:26150483

  1. Graphene electrostatic microphone and ultrasonic radio

    PubMed Central

    Zhou, Qin; Zheng, Jinglin; Onishi, Seita; Crommie, M. F.; Zettl, Alex K.

    2015-01-01

    We present a graphene-based wideband microphone and a related ultrasonic radio that can be used for wireless communication. It is shown that graphene-based acoustic transmitters and receivers have a wide bandwidth, from the audible region (20∼20 kHz) to the ultrasonic region (20 kHz to at least 0.5 MHz). Using the graphene-based components, we demonstrate efficient high-fidelity information transmission using an ultrasonic band centered at 0.3 MHz. The graphene-based microphone is also shown to be capable of directly receiving ultrasound signals generated by bats in the field, and the ultrasonic radio, coupled to electromagnetic (EM) radio, is shown to function as a high-accuracy rangefinder. The ultrasonic radio could serve as a useful addition to wireless communication technology where the propagation of EM waves is difficult. PMID:26150483

  2. Transmission electron microscopy studying of structural features of NiTi B2 phase formed under pulsed electron-beam impact

    SciTech Connect

    Meisner, Ludmila L.; Semin, Viktor O.; Gudimova, Ekaterina Y.; Neiman, Alexey A. Lotkov, Alexander I.; Ostapenko, Marina G.; Koval, Nikolai N.; Teresov, Anton D.

    2015-10-27

    By transmission electron microscopy method the evolution of structural-phase states on a depth of close to equiatomic NiTi modified layer has been studied. Modification performed by pulse impact on its surface low-energy high-current electron beam (beam energy density 10 J/sm{sup 2}, 10 pulses, pulse duration 50mks). It is established that during the treatment in the layer thickness of 8–10 μm, the melting of primary B2 phase and contained therein as Ti2Ni phase particles occurs. The result is change in the concentration ratio of titanium and nickel in the direction of increasing titanium content, which was confirmed by X-ray analysis in the form of increased unit cell parameter B2 phase. Analysis of the electron diffraction pattern showed that the modified layer is characterized as a highly distorted structure on the basis of bcc lattice. Lattice distortions are maximal near the surface and extends to a depth of melt. In subjacent layer there is gradual decline lattice distortions is observed.

  3. Ultrasonic Frequency Difference Generation to Characterize Fluids in Saturated Berea Sandstone.

    SciTech Connect

    Keatkowski, C. S.; Sinha, D. N.

    2001-01-01

    The use of nonlinear acoustics to characterize fluids in porous media is presented. The acoustic nonlinearity in sandstone is affected by the presence of water or oil. This difference in properties that affect the sound propagation through such media can be used to determine whether a piece of sandstone contains water or oil. Traditional methods of characterizing porous media usually rely on the transmission or reflection of a single ultrasonic probe pulse. The technique presented in this paper uses a method of generating a probe pulse inside the porous medium from the interaction of two pulses. Information about the medium is then contained in the propagation of this probe signal back to a receiver. The main advantage of this approach is that it allows implementation of this technique inside a borehole for characterizing the porous media outside.

  4. Ultrasonic temperature measurements with fiber optic system

    NASA Astrophysics Data System (ADS)

    Bi, Siwen; Wu, Nan; Zhou, Jingcheng; Ma, Tong; Liu, Yuqian; Cao, Chengyu; Wang, Xingwei

    2016-04-01

    Ultrasonic temperature measurements have been developed and widely applied in non-contact temperature tests in many industries. However, using optical fibers to build ultrasound generators are novel. This paper reports this new fiber optic ultrasonic system based on the generator of gold nanoparticles/polydimethylsiloxane (PDMS) composites. The optical acoustic system was designed to test the change of temperature on the aluminum plate and the temperature of the torch in the air. This paper explores the relationship between the ultrasonic transmission and the change of temperature. From the experimental results, the trend of ultrasonic speed was different in the aluminum plate and air with the change of temperature. Since the system can measure the average temperature of the transmission path, it will have significant influence on simulating the temperature distribution.

  5. Characterization of Heat Treated Titanium-Based Implants by Nondestructive Eddy Current and Ultrasonic Tests

    NASA Astrophysics Data System (ADS)

    Mutlu, Ilven; Ekinci, Sinasi; Oktay, Enver

    2014-06-01

    This study presents nondestructive characterization of microstructure and mechanical properties of heat treated Ti, Ti-Cu, and Ti-6Al-4V titanium-based alloys and 17-4 PH stainless steel alloy for biomedical implant applications. Ti, Ti-Cu, and 17-4 PH stainless steel based implants were produced by powder metallurgy. Ti-6Al-4V alloy was investigated as bulk wrought specimens. Effects of sintering temperature, aging, and grain size on mechanical properties were investigated by nondestructive and destructive tests comparatively. Ultrasonic velocity in specimens was measured by using pulse-echo and transmission methods. Electrical conductivity of specimens was determined by eddy current tests. Determination of Young's modulus and strength is important in biomedical implants. Young's modulus of specimens was calculated by using ultrasonic velocities. Calculated Young's modulus values were compared and correlated with experimental values.

  6. Ultrasonic inspection apparatus and method using a focused wave device

    SciTech Connect

    Gieske, John H.; Roach, Dennis P.; Walkington, Phillip D.

    2001-01-01

    An ultrasonic pulse echo inspection apparatus and method for detecting structural failures. A focus lens is coupled to the transducer to focus the ultrasonic signal on an area to be inspected and a stop is placed in the focus lens to block selected ultrasonic waves. Other waves are not blocked and are transmitted through the structure to arrive at interfaces therein concurrently to produce an echo response with significantly less distortion.

  7. Design of polarizers for a mega-watt long-pulse millimeter-wave transmission line on the large helical device

    SciTech Connect

    Ii, T. Kubo, S.; Shimozuma, T.; Kobayashi, S.; Okada, K.; Yoshimura, Y.; Igami, H.; Takahashi, H.; Ito, S.; Mizuno, Y.; Okada, K.; Mutoh, T.; Makino, R.; Kobayashi, K.; Goto, Y.

    2015-02-15

    The polarizer is one of the critical components in a high-power millimeter-wave transmission line. It requires full and highly efficient coverage of any polarization states, high-power tolerance, and low-loss feature. Polarizers with rounded shape at the edge of the periodic groove surface are designed and fabricated by the machining process for a mega-watt long-pulse millimeter-wave transmission line of the electron cyclotron resonance heating system in the large helical device. The groove shape of λ/8- and λ/4-type polarizers for an 82.7 GHz transmission line is optimally designed in an integral method developed in the vector theories of diffraction gratings so that the efficiency to realize any polarization state can be maximized. The dependence of the polarization states on the combination of the two polarizer rotation angles (Φ{sub λ/8}, Φ{sub λ/4}) is examined experimentally in a low-power test with the newly developed polarization monitor. The results show that the measured polarization characteristics are in good agreement with the calculated ones.

  8. A poroelastic model for ultrasonic wave attenuation in partially frozen brines

    NASA Astrophysics Data System (ADS)

    Matsushima, Jun; Nibe, Takao; Suzuki, Makoto; Kato, Yoshibumi; Rokugawa, Shuichi

    2011-02-01

    Although there are many possible mechanisms for the intrinsic seismic attenuation in composite materials that include fluids, relative motion between solids and fluids during seismic wave propagation is one of the most important attenuation mechanisms. In our previous study, we conducted ultrasonic wave transmission measurements on an ice-brine coexisting system to examine the influence on ultrasonic waves of the unfrozen brine in the pore microstructure of ice. In order to elucidate the physical mechanism responsible for ultrasonic wave attenuation in the frequency range of 350-600kHz, measured at different temperatures in partially frozen brines, we employed a poroelastic model based on the Biot theory to describe the propagation of ultrasonic waves through partially frozen brines. By assuming that the solid phase is ice and the liquid phase is the unfrozen brine, fluid properties measured by a pulsed nuclear magnetic resonance technique were used to calculate porosities at different temperatures. The computed intrinsic attenuation at 500kHz cannot completely predict the measured attenuation results from the experimental study in an ice-brine coexisting system, which suggests that other attenuation mechanisms such as the squirt-flow mechanism and wave scattering effect should be taken into account.

  9. Time delay estimation in the ultrasonic flowmeter in the oil well

    NASA Astrophysics Data System (ADS)

    Sun, Jian; Lin, Weijun; Zhang, Chengyu; Shen, Zhihui; Zhang, Hailan

    2010-01-01

    A new prototype of ultrasonic flowmeter used in the oil well is presented. The flowmeter depends on the time delay between the propagating times of the downstream and upstream ultrasonic pulses. The ultrasonic passageway is slanted to prevent the disadvantage introduced by the high viscosity of the oil. Two method of time delay estimation: threshold and cross-correlation are both studied and realized.

  10. Hand-Held Ultrasonic Instrument for Reading Matrix Symbols

    NASA Technical Reports Server (NTRS)

    Schramm, Harry F.; Kula, John P.; Gurney, John W.; Lior, Ephraim D.

    2008-01-01

    A hand-held instrument that would include an ultrasonic camera has been proposed as an efficient means of reading matrix symbols. The proposed instrument could be operated without mechanical raster scanning. All electronic functions from excitation of ultrasonic pulses through final digital processing for decoding matrix symbols would be performed by dedicated circuitry within the single, compact instrument housing.

  11. Accurate estimation of airborne ultrasonic time-of-flight for overlapping echoes.

    PubMed

    Sarabia, Esther G; Llata, Jose R; Robla, Sandra; Torre-Ferrero, Carlos; Oria, Juan P

    2013-01-01

    In this work, an analysis of the transmission of ultrasonic signals generated by piezoelectric sensors for air applications is presented. Based on this analysis, an ultrasonic response model is obtained for its application to the recognition of objects and structured environments for navigation by autonomous mobile robots. This model enables the analysis of the ultrasonic response that is generated using a pair of sensors in transmitter-receiver configuration using the pulse-echo technique. This is very interesting for recognizing surfaces that simultaneously generate a multiple echo response. This model takes into account the effect of the radiation pattern, the resonant frequency of the sensor, the number of cycles of the excitation pulse, the dynamics of the sensor and the attenuation with distance in the medium. This model has been developed, programmed and verified through a battery of experimental tests. Using this model a new procedure for obtaining accurate time of flight is proposed. This new method is compared with traditional ones, such as threshold or correlation, to highlight its advantages and drawbacks. Finally the advantages of this method are demonstrated for calculating multiple times of flight when the echo is formed by several overlapping echoes. PMID:24284774

  12. Accurate Estimation of Airborne Ultrasonic Time-of-Flight for Overlapping Echoes

    PubMed Central

    Sarabia, Esther G.; Llata, Jose R.; Robla, Sandra; Torre-Ferrero, Carlos; Oria, Juan P.

    2013-01-01

    In this work, an analysis of the transmission of ultrasonic signals generated by piezoelectric sensors for air applications is presented. Based on this analysis, an ultrasonic response model is obtained for its application to the recognition of objects and structured environments for navigation by autonomous mobile robots. This model enables the analysis of the ultrasonic response that is generated using a pair of sensors in transmitter-receiver configuration using the pulse-echo technique. This is very interesting for recognizing surfaces that simultaneously generate a multiple echo response. This model takes into account the effect of the radiation pattern, the resonant frequency of the sensor, the number of cycles of the excitation pulse, the dynamics of the sensor and the attenuation with distance in the medium. This model has been developed, programmed and verified through a battery of experimental tests. Using this model a new procedure for obtaining accurate time of flight is proposed. This new method is compared with traditional ones, such as threshold or correlation, to highlight its advantages and drawbacks. Finally the advantages of this method are demonstrated for calculating multiple times of flight when the echo is formed by several overlapping echoes. PMID:24284774

  13. Ultrasonic transducer

    SciTech Connect

    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.

  14. In plant demonstration of high temperature EM pulser and pulsed EMAT receiver: Final report: Experimental development and testing of ultrasonic system for high temperature applications on hot steel

    SciTech Connect

    Boyd, D.M.; Sperline, P.D.

    1988-11-01

    This report describes work performed under the Field Work Proposal on the ''In-Plant Demonstration of a High-Temperature EM Pulser and pulsed EMAT Receiver'' for the Department of Energy's Office of Industrial Programs. Cost sharing by the American Iron and Steel Institute (AISI) helped provide both technical guidance and equipment for the plant demonstration. This report covers the time period from January 1988 through September 1988.

  15. Ultrasonic Interferometers Revisited

    ERIC Educational Resources Information Center

    Greenslade, Thomas B., Jr.

    2007-01-01

    I have been tinkering with ultrasonic transducers once more. In earlier notes I reported on optics-like experiments performed with ultrasonics, described a number of ultrasonic interferometers, and showed how ultrasonic transducers can be used for Fourier analysis. This time I became interested in trying the technique of using two detectors in…

  16. Ultrasonic Interferometers Revisited

    NASA Astrophysics Data System (ADS)

    Greenslade, Thomas B.

    2007-03-01

    I have been tinkering with ultrasonic transducers once more. In earlier notes I reported on optics-like experiments performed with ultrasonics, described a number of ultrasonic interferometers,2 and showed how ultrasonic transducers can be used for Fourier analysis.3 This time I became interested in trying the technique of using two detectors in acoustic interferometers instead of the usual one.

  17. Ultrasonic pipe assessment

    SciTech Connect

    Thomas, Graham H.; Morrow, Valerie L.; Levie, Harold; Kane, Ronald J.; Brown, Albert E.

    2003-12-23

    An ultrasonic pipe or other structure assessment system includes an ultrasonic transducer positioned proximate the pipe or other structure. A fluid connection between the ultrasonic transducer and the pipe or other structure is produced. The ultrasonic transducer is moved relative to the pipe or other structure.

  18. Modern ultrasonic flowmeters

    NASA Astrophysics Data System (ADS)

    Gurevich, V. M.; Truman, S. G.

    1986-01-01

    The current status of ultrasonic flowmeters were reviewed on the basis of materials published in the Soviet Union and elsewhere. The following advantages of ultrasonic flowmeters over earlier instruments are cited. A comparative analysis is made of the design methods employed in ultrasonic flowmeters. The evolution of ultrasonic flowmetering is traced from the first generation and trends in their development are analyzed.

  19. Ultrasonic attenuation - Q measurements on 70215,29. [lunar rock

    NASA Technical Reports Server (NTRS)

    Warren, N.; Trice, R.; Stephens, J.

    1974-01-01

    Ultrasonic attenuation measurements have been made on an aluminum alloy, obsidian, and rock samples including lunar sample 70215,29. The measurement technique is based on a combination of the pulse transmission method and the forced resonance method. The technique is designed to explore the problem of defining experimentally, the Q of a medium or sample in which mode conversion may occur. If modes are coupled, the measured attenuation is strongly dependent on individual modes of vibration, and a range of Q-factors may be measured over various resonances or from various portions of a transient signal. On 70215,29, measurements were made over a period of a month while the sample outgassed in hard varuum. During this period, the highest measured Q of this sample increased from a few hundred into the range of 1000-1300.

  20. Ultrasonic properties of granular media saturated with dnapl/watermixtures

    SciTech Connect

    Ajo-Franklin, J.B.; Geller, J.T.; Harris, J.M.

    2007-09-15

    We present the results of four experiments investigating the ultrasonic properties of granular materials partially saturated with trichloroethylene (TCE), a dense non-aqueous contaminant. P-wave velocity measurements were made under in situ effective stress conditions using a pulse transmission cell at ?250 kHz. Two synthetic samples and two natural aquifer cores were fully saturated with water and then subjected to an axial injection of TCE. The resulting measurements show reductions in P-wave velocity of up to 15% due to contaminant saturation. A theoretical model combining Gassmann fluid substitution and Hill's equation was used to estimate the effects of DNAPL saturation; this model underpredicted observed reductions in velocity at high TCE saturations. A linear relationship, expressed in terms of volumetric contaminant fraction, provided an excellent empirical fit to the laboratory measurements.

  1. Ultrasonic techniques for aircraft ice accretion measurement

    NASA Technical Reports Server (NTRS)

    Hansman, R. John, Jr.; Kirby, Mark S.; Lichtenfelts, Fred

    1990-01-01

    Results of tests to measure ice growth in natural (flight) and artificial (icing wind tunnel) icing conditions are presented. Ice thickness is measured using an ultrasonic pulse-echo technique. Two icing regimes, wet and dry ice growth, are identified and the unique ultrasonic signal characteristics associated with these different types of ice growth are described. Ultrasonic measurements of ice growth on cylinders and airfoils exposed to artificial and natural icing conditions are presented. An accuracy of plus or minus 0.5 mm is achieved for ice thickness measurement using the pulse-echo technique. The performance of two-probe type ice detectors is compared to the surface mounted ultrasonic system. The ultrasonically measured ice accretion rates and ice surface condition (wet or dry) are used to compare the heat transfer characteristics for flight and icing wind tunnel environments. In general the heat transfer coefficient is inferred to be higher in the wind tunnel environment, not likely due to higher freestream turbulence levels. Finally, preliminary results of tests to measure ice growth on airfoil using an array of ultrasonic transducers are described. Ice profiles obtained during flight in natural icing conditions are shown and compared with mechanical and stereo image measurements.

  2. Absolute calibration technique for broadband ultrasonic transducers

    NASA Technical Reports Server (NTRS)

    Yost, William T. (Inventor); Cantrell, John H. (Inventor)

    1994-01-01

    Calibrating an ultrasonic transducer can be performed with a reduced number of calculations and testing. A wide-band pulser is connected to an ultrasonic transducer under test to generate ultrasonic waves in a liquid. A single frequency is transmitted to the electrostatic acoustic transducer (ESAT) and the voltage change produced is monitored. Then a broadband ultrasonic pulse is generated by the ultrasonic transducer and received by the ESAT. The output of the ESAT is amplified and input to a digitized oscilloscope for fast Fourier transform. The resulting plot is normalized with the monitored signal from the single frequency pulse. The plot is then corrected for characteristics of the membrane and diffraction effects. The transfer function of the final plot is determined. The transfer function gives the final sensitivity of the ultrasonic transducer as a function of frequency. The advantage of the system is the speed of calibrating the transducer by a reduced number of measurements and removal of the membrane and diffraction effects.

  3. Ultrasonic agitation-floating classification of nano-sized Ba-Mg ferrites particles formed by using self-propagating high temperature synthesis and fabrication of nickel-ferrites thin sheet by pulse-electroforming.

    PubMed

    Choi, Yong

    2013-01-01

    Nickel-nano-sized ferrites composites sheet for electromagnetic shielding was produced by pulse-electroforming in a modified nickel sulfamate solution. The ferrite particles were prepared by self-propagating high temperature synthesis (SHS) followed by mechanical milling, and classified with an ultrasonic agitation-floating unit to obtain about 100 nm in size. Average combustion temperature and combustion propagating rate during SHS reaction were 1190 K and 5.8 mm/sec at the oxygen pressure of 1.0 MPa, respectively. The nickel-ferrite composite sheet had preferred orientation which (100) pole clearly concentrated to normal direction, whereas, (110) and (111) poles tended to split to the longitudinal direction, respectively. Maximum magnetization, residual magnetization and coercive force of the nano-sized ferrites were 27.13 A x m2/kg, 6.4 A x m2/kg and 14.58 kA/m, respectively. Complex permeability of the composites decreased with an increase in frequency, and its real value (mu'r) had the maximum at about 0.3 GHz. The dielectric constants of the composites were epsilon'r = 6.7 and epsilon"r = 0. PMID:23646783

  4. Ultrasonic hydrometer

    SciTech Connect

    Swoboda, C.A.

    1984-04-17

    The disclosed ultrasonic hydrometer determines the specific gravity (density) of the electrolyte of a wet battery, such as a lead-acid battery. The hydrometer utilizes a transducer that when excited emits an ultrasonic impulse that traverses through the electrolyte back and forth between spaced sonic surfaces. The transducer detects the returning impulse, and means measures the time ''t'' between the initial and returning impulses. Considering the distance ''d'' between the spaced sonic surfaces and the measured time ''t'', the sonic velocity ''V'' is calculated with the equation ''V=2d/t''. The hydrometer also utilizes a thermocouple to measure the electrolyte temperature. A hydrometer database correlates three variable parameters including sonic velocity in and temperature and specific gravity of the electrolyte, for temperature values between 0/sup 0/ and 40/sup 0/ C. and for specific gravity values between 1.05 and 1.30. Upon knowing two parameters (the calculated sonic velocity and the measured temperature), the third parameter (specific gravity) can be uniquely found in the database. The hydrometer utilizes a microprocessor for data storage and manipulation. The disclosed modified battery has a hollow spacer nub on the battery side wall, the sonic surfaces being on the inside of the nub and the electrolyte filling between the surfaces to the exclusion of intervening structure. An accessible pad exposed on the nub wall opposite one sonic surface allows the reliable placement thereagainst of the transducer.

  5. Ultrasonic hydrometer

    DOEpatents

    Swoboda, Carl A.

    1984-01-01

    The disclosed ultrasonic hydrometer determines the specific gravity (density) of the electrolyte of a wet battery, such as a lead-acid battery. The hydrometer utilizes a transducer that when excited emits an ultrasonic impulse that traverses through the electrolyte back and forth between spaced sonic surfaces. The transducer detects the returning impulse, and means measures the time "t" between the initial and returning impulses. Considering the distance "d" between the spaced sonic surfaces and the measured time "t", the sonic velocity "V" is calculated with the equation "V=2d/t". The hydrometer also utilizes a thermocouple to measure the electrolyte temperature. A hydrometer database correlates three variable parameters including sonic velocity in and temperature and specific gravity of the electrolyte, for temperature values between 0.degree. and 40.degree. C. and for specific gravity values between 1.05 and 1.30. Upon knowing two parameters (the calculated sonic velocity and the measured temperature), the third parameter (specific gravity) can be uniquely found in the database. The hydrometer utilizes a microprocessor for data storage and manipulation. The disclosed modified battery has a hollow spacer nub on the battery side wall, the sonic surfaces being on the inside of the nub and the electrolyte filling between the surfaces to the exclusion of intervening structure. An accessible pad exposed on the nub wall opposite one sonic surface allows the reliable placement thereagainst of the transducer.

  6. Digital ultrasonic signal processing: Primary ultrasonics task and transducer characterization use and detailed description

    NASA Technical Reports Server (NTRS)

    Hammond, P. L.

    1979-01-01

    This manual describes the use of the primary ultrasonics task (PUT) and the transducer characterization system (XC) for the collection, processing, and recording of data received from a pulse-echo ultrasonic system. Both PUT and XC include five primary functions common to many real-time data acquisition systems. Some of these functions are implemented using the same code in both systems. The solicitation and acceptance of operator control input is emphasized. Those operations not under user control are explained.

  7. High resolution ultrasonic densitometer

    SciTech Connect

    Dress, W.B.

    1983-01-01

    The velocity of torsional stress pulses in an ultrasonic waveguide of non-circular cross section is affected by the temperature and density of the surrounding medium. Measurement of the transit times of acoustic echoes from the ends of a sensor section are interpreted as level, density, and temperature of the fluid environment surrounding that section. This paper examines methods of making these measurements to obtain high resolution, temperature-corrected absolute and relative density and level determinations of the fluid. Possible applications include on-line process monitoring, a hand-held density probe for battery charge state indication, and precise inventory control for such diverse fluids as uranium salt solutions in accountability storage and gasoline in service station storage tanks.

  8. Noncontact Acousto-Ultrasonics for Material Characterization

    NASA Technical Reports Server (NTRS)

    Kautz, Harold E.

    1998-01-01

    A NdYAG 1064 nm, laser pulse was employed to produce ultrasonic waves in specimens of SiC/SiC and SiC/Ti 6-4 composites which are high temperature materials of interest for aerospace applications. Air coupled transducers were used to detect and collect the signals used for acousto-ultrasonic analysis. Conditions for detecting ultrasonic decay signals were examined. The results were compared to those determined on the same specimens with contact coupling. Some non-contact measurements were made employing conventional air focused detectors. Others were performed with a more novel micromachined capacitance transducer. Concerns of the laser-in technology include potential destructiveness of the laser pulse. Repeated laser pulsing at the same location does lead to deterioration of the ultrasonic signal in some materials, but seems to recover with time. Also, unlike contact AU, the frequency regime employed is a function of laser-material interaction rather than the choice of transducers. Concerns of the air coupled-out technology include the effect of air attenuation. This imposes a practical upper limit to frequency of detection. In the case of the experimental specimens studied ultrasonic decay signals could be imaged satisfactorily.

  9. An adaptive neuro fuzzy inference system controlled space cector pulse width modulation based HVDC light transmission system under AC fault conditions

    NASA Astrophysics Data System (ADS)

    Ajay Kumar, M.; Srikanth, N. V.

    2014-03-01

    In HVDC Light transmission systems, converter control is one of the major fields of present day research works. In this paper, fuzzy logic controller is utilized for controlling both the converters of the space vector pulse width modulation (SVPWM) based HVDC Light transmission systems. Due to its complexity in the rule base formation, an intelligent controller known as adaptive neuro fuzzy inference system (ANFIS) controller is also introduced in this paper. The proposed ANFIS controller changes the PI gains automatically for different operating conditions. A hybrid learning method which combines and exploits the best features of both the back propagation algorithm and least square estimation method is used to train the 5-layer ANFIS controller. The performance of the proposed ANFIS controller is compared and validated with the fuzzy logic controller and also with the fixed gain conventional PI controller. The simulations are carried out in the MATLAB/SIMULINK environment. The results reveal that the proposed ANFIS controller is reducing power fluctuations at both the converters. It also improves the dynamic performance of the test power system effectively when tested for various ac fault conditions.

  10. Assessment and Calibration of a Crimp Tool Equipped with Ultrasonic Analysis Features

    NASA Technical Reports Server (NTRS)

    Yost, William T. (Inventor); Perey, Daniel F. (Inventor); Cramer, K. Elliott (Inventor)

    2013-01-01

    A method is provided for calibrating ultrasonic signals passed through a crimp formed with respect to a deformable body via an ultrasonically-equipped crimp tool (UECT). The UECT verifies a crimp quality using the ultrasonic signals. The method includes forming the crimp, transmitting a first signal, e.g., a pulse, to a first transducer of the UECT, and converting the first signal, using the first transducer, into a second signal which defines an ultrasonic pulse. This pulse is transmitted through the UECT into the crimp. A second transducer converts the second signal into a third signal, which may be further conditioned, and the ultrasonic signals are calibrated using the third signal or its conditioned variant. An apparatus for calibrating the ultrasonic signals includes a pulse module (PM) electrically connected to the first and second transducers, and an oscilloscope or display electrically connected to the PM for analyzing an electrical output signal therefrom.

  11. Pulse stretcher

    DOEpatents

    Horton, J.A.

    1994-05-03

    Apparatus for increasing the length of a laser pulse to reduce its peak power without substantial loss in the average power of the pulse is disclosed. The apparatus uses a White cell having a plurality of optical delay paths of successively increasing number of passes between the field mirror and the objective mirrors. A pulse from a laser travels through a multi-leg reflective path between a beam splitter and a totally reflective mirror to the laser output. The laser pulse is also simultaneously injected through the beam splitter to the input mirrors of the optical delay paths. The pulses from the output mirrors of the optical delay paths go simultaneously to the laser output and to the input mirrors of the longer optical delay paths. The beam splitter is 50% reflective and 50% transmissive to provide equal attenuation of all of the pulses at the laser output. 6 figures.

  12. An ultrasonic plethysmograph for space flight applications

    NASA Technical Reports Server (NTRS)

    Bhagat, P. K.; Lafferty, J. F.; Bowman, D.; Kadaba, M. P.

    1980-01-01

    The development of an ultrasonic plethysmograph based on the transit time measurement principle is reported, which meets the space-imposed requirements for evaluating cardiovascular deconditioning. It consists of a pulse generator, pulse receiver amplifier, voltage comparator, synchronous pulse generator, elapsed time counter, and transmit and receive piezoelectric crystals resonant at 2 MHz and of 3 mm diameter. The transit time for an ultrasonic pulse to propagate across a limb cross section is computed in a digital fashion using a 32 MHz clock, and resolution is 0.049 mm with the range being approximately 200 mm. Experimental results regarding dynamic system response were found comparable in both accuracy and sensitivity to those of a Whitney strain gage using a 50 torr venous occlusion.

  13. Ultrasonic position and velocity measurement for a moving object by M-sequence pulse compression using Doppler velocity estimation by spectrum-pattern analysis

    NASA Astrophysics Data System (ADS)

    Ikari, Yohei; Hirata, Shinnosuke; Hachiya, Hiroyuki

    2015-07-01

    Pulse compression using a maximum-length sequence (M-sequence) can improve the signal-to-noise ratio (SNR) of the reflected echo in the pulse-echo method. In the case of a moving object, however, the echo is modulated owing to the Doppler effect. The Doppler-shifted M-sequence-modulated signal cannot be correlated with the reference signal that corresponds to the transmitted M-sequence-modulated signal. Therefore, Doppler velocity estimation by spectrum-pattern analysis of a cyclic M-sequence-modulated signal and cross correlations with Doppler-shifted reference signals that correspond to the estimated Doppler velocities has been proposed. In this paper, measurements of the position and velocity of a moving object by the proposed method are described. First, Doppler velocities of the object are estimated using a microphone array. Secondly, the received signal from each microphone is correlated with each Doppler-shifted reference signal. Then, the position of the object is determined from the B-mode image formed from all cross-correlation functions. After that, the velocity of the object is calculated from velocity components estimated from the Doppler velocities and the position. Finally, the estimated Doppler velocities, determined positions, and calculated velocities are evaluated.

  14. Nonlinear Ultrasonic Testing on a Laboratory Concrete Bridge Deck

    NASA Astrophysics Data System (ADS)

    Roe, Shannon E.; Woodward, C.; Cramer, M. J.

    2007-03-01

    Nonlinear ultrasonic testing has been shown to be extremely sensitive to distributed damage in concrete. Nonlinear nondestructive ultrasonic tests were performed on a laboratory bridge to detect distributed damage in the deck after it had been overloaded. The NLUT detected damage throughout the deck, and of particular interest in locations where damage was not visible. These results were compared to results obtained using pulse velocity tests at the same locations. The nonlinear ultrasonics were several orders of magnitude more sensitive than results obtained from pulse velocity.

  15. Wire Crimp Termination Verification Using Ultrasonic Inspection

    NASA Technical Reports Server (NTRS)

    Perey, Daniel F.; Cramer, K. Elliott; Yost, William T.

    2007-01-01

    The development of a new ultrasonic measurement technique to quantitatively assess wire crimp terminations is discussed. The amplitude change of a compressional ultrasonic wave propagating through the junction of a crimp termination and wire is shown to correlate with the results of a destructive pull test, which is a standard for assessing crimp wire junction quality. Various crimp junction pathologies such as undercrimping, missing wire strands, incomplete wire insertion, partial insulation removal, and incorrect wire gauge are ultrasonically tested, and their results are correlated with pull tests. Results show that the nondestructive ultrasonic measurement technique consistently (as evidenced with destructive testing) predicts good crimps when ultrasonic transmission is above a certain threshold amplitude level. A physics-based model, solved by finite element analysis, describes the compressional ultrasonic wave propagation through the junction during the crimping process. This model is in agreement within 6% of the ultrasonic measurements. A prototype instrument for applying this technique while wire crimps are installed is also presented. The instrument is based on a two-jaw type crimp tool suitable for butt-splice type connections. Finally, an approach for application to multipin indenter type crimps will be discussed.

  16. A unique method to study acoustic transmission through ducts using signal synthesis and averaging of acoustic pulses

    NASA Technical Reports Server (NTRS)

    Salikuddin, M.; Ramakrishnan, R.; Ahuja, K. K.; Brown, W. H.

    1981-01-01

    An acoustic impulse technique using a loudspeaker driver is developed to measure the acoustic properties of a duct/nozzle system. A signal synthesis method is used to generate a desired single pulse with a flat spectrum. The convolution of the desired signal and the inverse Fourier transform of the reciprocal of the driver's response are then fed to the driver. A signal averaging process eliminates the jet mixing noise from the mixture of jet noise and the internal noise, thereby allowing very low intensity signals to be measured accurately, even for high velocity jets. A theoretical analysis is carried out to predict the incident sound field; this is used to help determine the number and locations of the induct measurement points to account for the contributions due to higher order modes present in the incident tube method. The impulse technique is validated by comparing experimentally determined acoustic characteristics of a duct-nozzle system with similar results obtained by the impedance tube method. Absolute agreement in the comparisons was poor, but the overall shapes of the time histories and spectral distributions were much alike.

  17. Federal technology alert: Ultrasonic humidifiers

    SciTech Connect

    1998-11-01

    Humidifiers are used in buildings to maintain humidity levels to ensure quality and handling capabilities in manufacturing processes, to lower the transmission rate of disease-causing bacteria in hospitals, to reduce static electricity in manufacturing clean rooms and in computer rooms, and to provide higher levels of employee comfort in offices. Ultrasonic humidifiers generate a water mist without raising its temperature. An electronic oscillation is converted to a mechanical oscillation using a piezo disk immersed in a reservoir of mineral-free water. The mechanical oscillation is directed at the surface of the water, where at very high frequencies it creates a very fine mist of water droplets. This adiabatic process, which does not heat the supply water, reduces humidifier energy use by 90 to 93% compared with systems that do boil the water. Ultrasonic humidifiers have been demonstrated to be more efficient and to require less maintenance than competing humidifier technologies such as electrode canisters, quartz lamps, and indirect steam-to-steam. They do not require anticorrosive additives that affect the indoor air quality of buildings using direct steam humidifiers. There are two potential disadvantages of ultrasonic humidifiers. They must use mineral-free, deionized water or water treated with reverse osmosis. Treated water reduces maintenance costs because it eliminates calcium deposits, but increases other operating costs. Also, the cool mist from ultrasonic humidifiers absorbs energy from the supply air as it evaporates and provides a secondary cooling effect.

  18. Measuring Thicknesses With In Situ Ultrasonic Transducers

    NASA Technical Reports Server (NTRS)

    Dunn, Daniel E.; Cerino, Joseph R.

    1995-01-01

    Several pulsed ultrasonic transducers attached to workpiece for measurement of changes in thicknesses of workpiece at transducer locations during grinding and polishing, according to proposal. Once attached, each transducer remains attached at original position until all grinding and polishing operations complete. In typical application, workpiece glass or ceramic blank destined to become component of optical system.

  19. Fundamentals of picosecond laser ultrasonics.

    PubMed

    Matsuda, Osamu; Larciprete, Maria Cristina; Li Voti, Roberto; Wright, Oliver B

    2015-02-01

    The aim of this article is to provide an introduction to picosecond laser ultrasonics, a means by which gigahertz-terahertz ultrasonic waves can be generated and detected by ultrashort light pulses. This method can be used to characterize materials with nanometer spatial resolution. With reference to key experiments, we first review the theoretical background for normal-incidence optical detection of longitudinal acoustic waves in opaque single-layer isotropic thin films. The theory is extended to handle isotropic multilayer samples, and is again compared to experiment. We then review applications to anisotropic samples, including oblique-incidence optical probing, and treat the generation and detection of shear waves. Solids including metals and semiconductors are mainly discussed, although liquids are briefly mentioned. PMID:24998119

  20. Autonomous data transmission apparatus

    DOEpatents

    Kotlyar, Oleg M.

    1997-01-01

    A autonomous borehole data transmission apparatus for transmitting measurement data from measuring instruments at the downhole end of a drill string by generating pressure pulses utilizing a transducer longitudinally responsive to magnetic field pulses caused by electrical pulses corresponding to the measured downhole parameters.

  1. Electrochemical 'bubble swarm' enhancement of ultrasonic surface cleaning.

    PubMed

    Birkin, P R; Offin, D G; Vian, C J B; Leighton, T G

    2015-09-01

    An investigation of surface cleaning using a swarm of gas bubbles within an acoustically activated stream is presented. Electrolysis of water at Pt microwires (100 μm diameter) to produce both hydrogen and oxygen bubbles is shown to enhance the extent of ultrasonic surface cleaning in a free flowing water stream containing an electrolyte (0.1 M Na2SO4) and low surfactant concentration (2 mM SDS). The surfactant was employed to allow control of the average size of the bubble population within the swarm. The electrochemical bubble swarm (EBS) is shown to perturb acoustic transmission through the stream. To optimise the cleaning process both the ultrasonic field and the electrochemical current are pulsed and synchronized but with different duty cycles. Cleaning action is demonstrated on structured surfaces (porcine skin and finger mimics) loaded with fluorescent particles. This action is shown to be significantly enhanced compared to that found with an inherent bubble population produced by the flow and acoustic regime alone under the same conditions. PMID:26234563

  2. Harmonic amplitude distribution in a wideband ultrasonic wavefront after propagation through human abdominal wall and breast specimens.

    PubMed

    Liu, D L; Waag, R C

    1997-02-01

    The amplitude characteristics of ultrasonic wavefront distortion produced by transmission through the abdominal wall and breast is described. Ultrasonic pulses were recorded in a two-dimensional aperture after transmission through specimens of abdominal wall or breast. After the pulse arrival times were corrected for geometric path differences, the pulses were temporally Fourier transformed and two-dimensional maps of harmonic amplitudes in the measurement aperture were computed. The results indicate that, as the temporal frequency increases, the fluctuation in harmonic amplitudes increases but the spatial scale of the fluctuation decreases. The normalized second-order and third-order moments of the amplitude distribution also increase with temporal frequency. The wide range variation of these distribution characteristics could not be covered by the Rayleigh, Rician, or K-distribution because of their limited flexibility. However, the Weibull distribution and especially the generalized K-distribution provide better fits to the data. In the fit of the generalized K-distribution, a decrease of its parameter alpha with increasing temporal frequency was observed, as predicted by analysis based on a phase screen model. PMID:9035403

  3. Inexpensive Ultrasonic Interferometer

    NASA Astrophysics Data System (ADS)

    Grossmann, John; Svitelskiy, Oleksiy; Suslov, Alexey

    2013-03-01

    Growing interest of small universities and colleges in research determines an increasing need in affordable laboratory equipment that would be capable of producing scientifically valuable experimental results. In this report we present the current status of our efforts to develop a simple and low-cost version of a classical experimental setup for ultrasonic pulse-echo measurements that would be easily reproducible in the electronics shop of any small educational institution. In particular, usage of a dual timer microchip LM556 allowed us to simplify the design of a probing pulse generator. Also, we propose that using modern broadband RF components in phase detection circuits will allow us to substitute the complicated and expensive superheterodyne design of receiver with the technique of direct transformation and analysis of the echo signal right at the probe frequency. Our analysis shows that these simplifications can be achieved without compromising for sensitivity of the experiment or precision of measurements. This work is supported by Research Council of Colgate University

  4. Production of aqueous spherical gold nanoparticles using conventional ultrasonic bath

    PubMed Central

    2012-01-01

    A conventional ultrasonic bath was used to examine the feasibility of forming aqueous spherical gold nanoparticles (GNPs) under atmospheric conditions. The effects of ultrasonic energy on the size and morphology of GNPs were also investigated. Highly monodispersed spherical GNPs were successfully synthesised by sodium citrate reduction in a conventional ultrasonic bath, without an additional heater or magnetic stirrer, as evidenced by ultraviolet–visible spectra and transmission electron microscopy. Ultrasonic energy was shown to be a key parameter for producing spherical GNPs of tunable sizes (20 to 50 nm). A proposed scheme for understanding the role of ultrasonic energy in the formation and growth of GNPs was discussed. The simple single-step method using just a conventional ultrasonic bath as demonstrated in this study offers new opportunities in the production of aqueous suspensions of monodispersed spherical GNPs. PMID:22839598

  5. Effective ultrasonication process for better colloidal dispersion of nanofluid.

    PubMed

    Mahbubul, I M; Saidur, R; Amalina, M A; Elcioglu, E B; Okutucu-Ozyurt, T

    2015-09-01

    Improving dispersion stability of nanofluids through ultrasonication has been shown to be effective. Determining specific conditions of ultrasonication for a certain nanofluid is necessary. For this purpose, nanofluids of varying nanoparticle concentrations were prepared and studied to find out a suitable and rather mono-dispersed concentration (i.e., 0.5 vol.%, determined through transmission electron microscopy (TEM) analyses). This study aims to report applicable ultrasonication conditions for the dispersion of Al2O3 nanoparticles within H2O through the two-step production method. The prepared samples were ultrasonicated via an ultrasonic horn for 1-5h at two different amplitudes (25% and 50%). The microstructure, particle size distribution (PSD), and zeta potentials were analyzed to investigate the dispersion characteristics. Better particle dispersion, smaller aggregate sizes, and higher zeta potentials were observed at 3 and 5h of ultrasonication duration for the 50% and 25% of sonicator power amplitudes, respectively. PMID:25616639

  6. Ultrasonic airborne insertion loss measurements at normal incidence (L).

    PubMed

    Farley, Jayrin; Anderson, Brian E

    2010-12-01

    Transmission loss and insertion loss measurements of building materials at audible frequencies are commonly made using plane wave tubes or as a panel between reverberant rooms. These measurements provide information for noise isolation control in architectural acoustics and in product development. Airborne ultrasonic sound transmission through common building materials has not been fully explored. Technologies and products that utilize ultrasonic frequencies are becoming increasingly more common, hence the need to conduct such measurements. This letter presents preliminary measurements of the ultrasonic insertion loss levels for common building materials over a frequency range of 28-90 kHz using continuous-wave excitation. PMID:21218864

  7. ULTRASONIC NEUTRON DOSIMETER

    DOEpatents

    Truell, R.; de Klerk, J.; Levy, P.W.

    1960-02-23

    A neutron dosimeter is described which utilizes ultrasonic waves in the megacycle region for determination of the extent of neutron damage in a borosilicate glass through ultrasonic wave velocity and attenuation measurements before and after damage.

  8. System and method for ultrasonic tomography

    DOEpatents

    Haddad, Waleed Sami

    2002-01-01

    A system and method for doing both transmission mode and reflection mode three-dimensional ultrasonic imagining. The multimode imaging capability may be used to provide enhanced detectability of cancer tumors within human breast, however, similar imaging systems are applicable to a number of other medical problems as well as a variety of non-medical problems in non-destructive evaluation (NDE).

  9. Ultrasonic imaging techniques for breast cancer detection.

    SciTech Connect

    Goulding, N. R.; Marquez, J. D.; Prewett, E. M.; Claytor, T. N.; Nadler, B. R.; Huang, L.

    2006-01-01

    Improving the resolution and specificity of current ultrasonic imaging technology can enhance its relevance to detection of early-stage breast cancers. Ultrasonic evaluation of breast lesions is desirable because it is quick, inexpensive, and does not expose the patient to potentially harmful ionizing radiation. Improved image quality and resolution enables earlier detection and more accurate diagnoses of tumors, thus reducing the number of biopsies performed, increasing treatment options, and lowering mortality, morbidity, and remission percentages. In this work, a novel ultrasonic imaging reconstruction method that exploits straight-ray migration is described. This technique, commonly used in seismic imaging, accounts for scattering more accurately than standard ultrasonic approaches, thus providing superior image resolution. A breast phantom with various inclusions is imaged using a pulse-echo approach. The data are processed using the ultrasonic migration method and results are compared to standard linear ultrasound and to x-ray computed tomography (CT) scans. For an ultrasonic frequency of 2.25 MHz, imaged inclusions and features of approximately 1mm are resolved, although better resolution is expected with minor modifications. Refinement of this application using other imaging techniques such as time-reversal mirrors (TRM), synthetic aperture focusing technique (SAFT), decomposition of the time reversal operator (DORT), and factorization methods is also briefly discussed.

  10. Ultrasonic characterization of laser ablation

    NASA Astrophysics Data System (ADS)

    Smith, J. A.; Telschow, K. L.

    When a pulsed laser beam strikes the surface of an absorbing material, ultrasonic waves are generated due to thermoelectric expansion and, at higher laser power densities, ablation of the material. These sound generation mechanisms have been the subject of numerous theoretical and experimental studies and are now fairly well understood. In particular, it has been established that at low power densities the thermoelastic mechanism is well described by a surface center of expansion. This mechanism produces a characteristic waveform whose amplitude is proportional to the energy absorbed from the laser pulse and also dependent on the thermal and elastic properties of the material. The ablation ultrasonic source can be described by a point normal force acting on the material surface. For laser power densities near the ablation onset, the time dependence of the source is that of the laser pulse. The resultant waveform recorded on epicenter (source and detector collinear) has a sharp peak determined by the momentum impulse delivered to the material by the ablation process. Particularly in the near ablation onset region, this ultrasonic displacement peak can be used to characterize the ablation process occurring at the material surface. The onset power density for ablation and subsequent ablation dependence on power density are material dependent and thought to be a function of the heat capacity and thermal conductivity of the material. With this in mind, it is possible that these ablation signals could be used to characterize material microstructures, and perhaps material mechanical properties such as hardness, through microstructural changes of the material thermal parameters. This paper explores this question for samples of Type 304 stainless steel with microstructures controlled through work hardening and annealing.

  11. Ultrasonic search wheel probe

    DOEpatents

    Mikesell, Charles R.

    1978-01-01

    A device is provided for reducing internal reflections from the tire of an ultrasonic search wheel probe or from within the material being examined. The device includes a liner with an anechoic chamber within which is an ultrasonic transducer. The liner is positioned within the wheel and includes an aperture through which the ultrasonic sound from the transducer is directed.

  12. Modal dispersion, pulse broadening and maximum transmission rate in GRIN optical fibers encompass a central dip in the core index profile

    NASA Astrophysics Data System (ADS)

    El-Diasty, Fouad; El-Hennawi, H. A.; El-Ghandoor, H.; Soliman, Mona A.

    2013-12-01

    Intermodal and intramodal dispersions signify one of the problems in graded-index multi-mode optical fibers (GRIN) used for LAN communication systems and for sensing applications. A central index dip (depression) in the profile of core refractive-index may occur due to the CVD fabrication processes. The index dip may also be intentionally designed to broaden the fundamental mode field profile toward a plateau-like distribution, which have advantages for fiber-source connections, fiber amplifiers and self-imaging applications. Effect of core central index dip on the propagation parameters of GRIN fiber, such as intermodal dispersion, intramodal dispersion and root-mean-square broadening, is investigated. The conventional methods usually study optical signal propagation in optical fiber in terms of mode characteristics and the number of modes, but in this work multiple-beam Fizeau interferometry is proposed as an inductive but alternative methodology to afford a radial approach to determine dispersion, pulse broadening and maximum transmission rate in GRIN optical fiber having a central index dip.

  13. Resolution and quantitative accuracy improvements in ultrasound transmission imaging

    NASA Astrophysics Data System (ADS)

    Chenevert, T. L.

    The type of ultrasound transmission imaging, referred to as ultrasonic computed tomography (UCT), reconstructs distributions of tissue speed of sound and sound attenuation properties from measurements of acoustic pulse time of flight (TCF) and energy received through tissue. Although clinical studies with experimental UCT scanners have demonstrated UCT is sensitive to certain tissue pathologies not easily detected with conventional ultrasound imaging, they have also shown UCT to suffer from artifacts due to physical differences between the acoustic beam and its ray model implicit in image reconstruction algorithms. Artifacts are expressed as large quantitative errors in attenuation images, and poor spatial resolution and size distortion (exaggerated size of high speed of sound regions) in speed of sound images. Methods are introduced and investigated which alleviate these problems in UCT imaging by providing improved measurements of pulse TCF and energy.

  14. Analysis of microcracks in dry polycrystalline NaCl by ultrasonic signal processing

    SciTech Connect

    Sears, F.M.

    1980-07-01

    The attenuation of energy and the change in shape of transient waveforms is a basic feature associated with the propagation of waves in crustal rocks. The dimensionless quality factor Q is observed as a useful quantity to characterize the attenuation of energy. Existing an elastic (attenuation) theories on the Q-determination problem are compared with experimental measurements to better understand rock properties. Experimental attenuation measurements were made on Avery Island (Louisiana) rock salt, Westerly (Rhode Island) granite, and Creighton (Ontario) quartz biotite gabbro. The attenuation mechanisms and how they affect the agreement between the an elastic theories were examined. Ultrasonic pulse methods were utilized of examine crack geometries as a function of frequency and thermal cycling temperature in dry polycrystalline rock salt. The attenuation of compressional (P) and shear (S) waves was studied in a thermally-induced, isotropic distribution of microcracks using ultrasonic-transmission techniques. These attenuation measurements led to the following series of generalities: ultrasonic or seismic attenuation depends on frequency in the rocks tested; thermal cycling of rock salt increases the porosity and attenuation; grain scattering seems to be the dominant loss mechanism at the higher frequencies in rocks; friction explains why the introduction of cracks into rock salt increases the attenuation; and attenuation appears to be independent of strain amplitude for low strains (10/sup -6/) such as those associated with these measurements. Much work remains to be done to adequately describe the attenuation loss mechanisms and the an elasticity of rocks both experimentally and theoretically.

  15. Ultrasonic angle beam standard reflector. [ultrasonic nondestructive inspection

    NASA Technical Reports Server (NTRS)

    Berry, R. F., Jr. (Inventor)

    1985-01-01

    A method that provides an impression profile in a reference standard material utilized in inspecting critically stressed components with pulsed ultrasound is described. A die stamp having an I letter is used to impress the surface of a reference material. The die stamp is placed against the surface and struck with an inertia imparting member to impress the I in the reference standard material. Upset may appear on the surface as a result of the impression and is removed to form a smooth surface. The stamping and upset removal is repeated until the entire surface area of a depth control platform on the die stamp uniformly contacts the material surface. The I impression profile in the reference standard material is utilized for reflecting pulsed ultrasonic beams for inspection purposes.

  16. Increased epidermal laser fluence through simultaneous ultrasonic microporation

    NASA Astrophysics Data System (ADS)

    Whiteside, Paul J. D.; Chininis, Jeff A.; Schellenberg, Mason W.; Qian, Chenxi; Hunt, Heather K.

    2016-03-01

    Lasers have demonstrated widespread applicability in clinical dermatology as minimally invasive instruments that achieve photogenerated responses within tissue. However, before reaching its target, the incident light must first transmit through the surface layer of tissue, which is interspersed with chromophores (e.g. melanin) that preferentially absorb the light and may also generate negative tissue responses. These optical absorbers decrease the efficacy of the procedures. In order to ensure that the target receives a clinically relevant dose, most procedures simply increase the incident energy; however, this tends to exacerbate the negative complications of melanin absorption. Here, we present an alternative solution aimed at increasing epidermal energy uence while mitigating excess absorption by unintended targets. Our technique involves the combination of a waveguide-based contact transmission modality with simultaneous high-frequency ultrasonic pulsation, which alters the optical properties of the tissue through the agglomeration of dissolved gasses into micro-bubbles within the tissue. Doing so effectively creates optically transparent pathways for the light to transmit unobstructed through the tissue, resulting in an increase in forward scattering and a decrease in absorption. To demonstrate this, Q-switched nanosecond-pulsed laser light at 532nm was delivered into pig skin samples using custom glass waveguides clad in titanium and silver. Light transmission through the tissue was measured with a photodiode and integrating sphere for tissue with and without continuous ultrasonic pulsation at 510 kHz. The combination of these techniques has the potential to improve the efficiency of laser procedures while mitigating negative tissue effects caused by undesirable absorption.

  17. Ultrasonic Microtransport

    NASA Astrophysics Data System (ADS)

    Moroney, Richard Morgan, III

    We have observed numerous kinetic effects using ultrasonic flexural plate waves (FPWs) in 4mu -thick composite plates of low-stress silicon nitride, piezoelectric zinc oxide and aluminum. The wavelength is typically 100 mum, and the area 3 x 8 mm^2. A successful new surface micromachining fabrication process is presented here for the first time. FPWs have been used to move liquids and gasses with motion typically indicated by polysilicon blocks in air and polystyrene spheres in water; the velocity in air is 4.5 mm/s (with a zero-to-peak input of 3 V), and in water it is 100 mum/s (with an input of 7.8 V). Other observations include pumping of a liquid dye, and mixing near the FPW surface. All quantitative observations demonstrate that the kinetic effects of FPWs are proportional to the square of the wave amplitude. The amplitude for a typical device is 250 A at 9 V input; the power in a typical FPW is about 2 mW. The amplitude can be accurately measured using a laser diffraction technique. Experimental error is about +/-10%, and many of the results agree well with a simple theory to predict the FPW amplitude; extensions of the theory model the fluid loading of FPW devices, but experiment and theory disagree by about 15%. Pumping by flexural plate waves is an example of the phenomenon known as acoustic streaming. A common solution approach is the method of successive approximations, where the nonlinear equations are first linearized and solved. This "first-order" solution is then used to determine the inhomogeneous source terms in the linearized, "second -order" equations of motion. Theoretical predictions of streaming theory are in excellent agreement with experiment in the case where the FPW device contacts a half-space of fluid; predictions for flow in small channels encourage the development of integrated micropumps. Applications for microflow include thermal redistribution in integrated circuits and liquid movement in analytical instruments--particularly where

  18. Design of embedded endoscopic ultrasonic imaging system

    NASA Astrophysics Data System (ADS)

    Li, Ming; Zhou, Hao; Wen, Shijie; Chen, Xiodong; Yu, Daoyin

    2008-12-01

    Endoscopic ultrasonic imaging system is an important component in the endoscopic ultrasonography system (EUS). Through the ultrasonic probe, the characteristics of the fault histology features of digestive organs is detected by EUS, and then received by the reception circuit which making up of amplifying, gain compensation, filtering and A/D converter circuit, in the form of ultrasonic echo. Endoscopic ultrasonic imaging system is the back-end processing system of the EUS, with the function of receiving digital ultrasonic echo modulated by the digestive tract wall from the reception circuit, acquiring and showing the fault histology features in the form of image and characteristic data after digital signal processing, such as demodulation, etc. Traditional endoscopic ultrasonic imaging systems are mainly based on image acquisition and processing chips, which connecting to personal computer with USB2.0 circuit, with the faults of expensive, complicated structure, poor portability, and difficult to popularize. To against the shortcomings above, this paper presents the methods of digital signal acquisition and processing specially based on embedded technology with the core hardware structure of ARM and FPGA for substituting the traditional design with USB2.0 and personal computer. With built-in FIFO and dual-buffer, FPGA implement the ping-pong operation of data storage, simultaneously transferring the image data into ARM through the EBI bus by DMA function, which is controlled by ARM to carry out the purpose of high-speed transmission. The ARM system is being chosen to implement the responsibility of image display every time DMA transmission over and actualizing system control with the drivers and applications running on the embedded operating system Windows CE, which could provide a stable, safe and reliable running platform for the embedded device software. Profiting from the excellent graphical user interface (GUI) and good performance of Windows CE, we can not

  19. Passive wireless ultrasonic transducer systems

    NASA Astrophysics Data System (ADS)

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

    2014-02-01

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

  20. Ultrasonic monitoring of pitting corrosion

    NASA Astrophysics Data System (ADS)

    Jarvis, A. J. C.; Cegla, F. B.; Bazaz, H.; Lozev, M.

    2013-01-01

    Exposure to corrosive substances in high temperature environments can cause damage accumulation in structural steels, particularly in the chemical and petrochemical industries. The interaction mechanisms are complex and varied; however initial damage propagation often manifests itself in the form of localized areas of increased material loss. Recent development of an ultrasonic wall thickness monitoring sensor capable of withstanding temperatures in excess of 500°C has allowed permanent monitoring within such hostile environments, providing information on how the shape of a pulse which has reflected from a corroding surface can change over time. Reconstructing localized corrosion depth and position may be possible by tracking such changes in reflected pulse shape, providing extra information on the state of the backwall and whether process conditions should be altered to increase plant life. This paper aims to experimentally investigate the effect certain localized features have on reflected pulse shape by `growing' artificial defects into the backwall while wall thickness is monitored using the sensor. The size and complexity of the three dimensional scattering problem lead to the development of a semi-analytical simulation based on the distributed point source method (DPSM) which is capable of simulating pulse reflection from complex surfaces measuring approximately 17×10λ Comparison to experimental results show that amplitude changes are predicted to within approximately 1dB and that pulse shape changes are accurately modelled. All experiments were carried out at room temperature, measurements at high temperature will be studied in the future.

  1. High voltage pulse conditioning

    DOEpatents

    Springfield, Ray M.; Wheat, Jr., Robert M.

    1990-01-01

    Apparatus for conditioning high voltage pulses from particle accelerators in order to shorten the rise times of the pulses. Flashover switches in the cathode stalk of the transmission line hold off conduction for a determinable period of time, reflecting the early portion of the pulses. Diodes upstream of the switches divert energy into the magnetic and electrostatic storage of the capacitance and inductance inherent to the transmission line until the switches close.

  2. a Theoretical Study of the Kinetic Processes in a High-Power Xenon Chloride Excimer Laser Oscillator Driven by a Long Transmission Line Pulse Forming Network.

    NASA Astrophysics Data System (ADS)

    Wang, Yuh-Shuh

    1982-03-01

    The avalanche/self-sustained discharge rare gas halide (RGH) excimer lasers driven by a transmission line type pulse forming network (PFN) belong to a novel class of discharge pumped gas lasers operating in the visible and ultraviolet wavelengths efficiently. The kinetics in this class of lasers, however, has not yet been fully understood. Therefore, it seems essential at this point to study the characteristics of the discharge plasma in such a device and determine the major energy flow paths in the active media before one attempts to optimize the operating conditions or deduce the scaling rules. The work presented here is the theoretical modeling of the discharge pumped XeCl laser driven by a long transmission line (two way transit time, 200 nsec). The mathematical formulation consisting of the rate equations, the temperature equation, the circuit equation, and the Boltzmann equation governing the velocity and energy distributions of the free electrons is developed under the assumptions that the applied electric field strength is spatially uniform and the number densities of all important chemical species are spatially homogeneous in the discharge volume. These coupled non-linear differential equations are solved numerically by using the GBS extrapolation method simultaneously with the time evolution of the electron mole fraction during the transient discharge. The time-dependent electron velocity and energy distribution functions are obtained from the numerical solutions of the Boltzmann equation, with all elastic (including electron-electron), inelastic, attachment, recombination, and ionization collisions included, by a self-consistent iteration technique. The kinetic reactions involved in the XeCl laser using Ne/Xe/HCl and He/Xe/HCl mixtures are comprehensively examined. The results of this study reveal that the new processes. e + XeCl('*) (--->) Xe('*) + Cl('-),. e + XeCl (--->) Xe + Cl('-) or Xe + Cl + e,. are important and have to be included in the model

  3. Air-coupled ultrasonic measurements in composites

    NASA Astrophysics Data System (ADS)

    Kommareddy, Vamshi; Peters, John J.; Hsu, David K.

    2005-04-01

    Air-coupled ultrasound is a non-contact technique and has clear advantages over water-coupled testing. This work aims at gaining quantitative understanding of the principles underlining air-coupled ultrasonic measurement. The transmission of air-coupled ultrasonic energy through a plate is measured experimentally; model calculation of the transmission coefficient, taking into account the real transducer characteristics, is compared with the experimental results. The occurrence of "Poisson bright spot" in the flaw images of thin laminates and honeycomb composites were investigated; A qualitative comparison with a model based on the Fresnel's wave theory of light is discussed. Through transmission C-scans at 120 and 400 kHz using focused transmitter and receiver were studied.

  4. Numerical calculations of ultrasonic fields. [STEALTH

    SciTech Connect

    Johnson, J.A.

    1982-02-01

    A code for calculating ultrasonic fields has been developed by revisng the thermal-hydraulics code STEALTH. This code may be used in a wide variety of situations in which a detailed knowledge of a propagating wave field is required. Among the potential used are: interpretation of pulse-echo or pitch-catch ultrasonic signals in complicated geometries; ultrasonic transducer modeling and characterization; optimization and evaluation of transducer design; optimization and reliability of inspection procedures; investigation of the response of different types of reflectors; flaw modeling; and general theoretical acoustics. The code is described, and its limitations and potential are discussed. A discussion of the required input and of the general procedures for running the code is presented. Three sample problems illustrate the input and the use of the code.

  5. Flexible ultrasonic array sensors for health monitoring

    NASA Astrophysics Data System (ADS)

    Kobayashi, M.; Wu, K.-T.; Song, L.; Liu, Q.; Jen, C.-K.

    2007-04-01

    Flexible ultrasonic array transducers which can be attached to the desired structures or materials for nondestructive testing and structural health monitoring applications at room and elevated temperatures are developed. These flexible ultrasonic transducers (UTs) arrays consist of a thin polyimide membrane with a bottom electrode or stainless steel foil, a piezoelectric lead-zirconate-titanate (PZT) composite film and top electrodes. The flexibility is realized owing to the porosity of piezoelectric film and the thinness of substrate and electrodes. Top and bottom electrode materials are silver paste, silver paint or electroless plated nickel alloys. The UT array is configured by the several top electrodes. The flexible UT has been successfully tested at 150°C and also immersed into water as immersion ultrasonic probe operated in the pulse-echo mode with good signal to noise ratio.

  6. Acousto-ultrasonic characterization of fiber reinforced composites

    NASA Technical Reports Server (NTRS)

    Vary, A.

    1981-01-01

    The acousto-ultrasonic technique combines advantageous aspects of acoustic emission and ultrasonic methodologies. Acousto-ultrasonics operates by introducing a repeating series of ultrasonic pulses into a material. The waves introduced simulate the spontaneous stress waves that would arise if the material were put under stress as in the case of acoustic emission measurements. These benign stress waves are detected by an acoustic emission sensor. The physical arrangement of the ultrasonic (input) transducer and acoustic emission (output) sensor is such that the resultant waveform carries an imprint of morphological factors that govern or contribute to material performance. The output waveform is complex, but it can be quantitized in terms of a 'stress wave factor.' The stress wave factor, which can be defined in a number of ways, is a relative measure of the efficiency of energy dissipation in a material. If flaws or other material anomalies exist in the volume being examined, their combined effect appears in the stress wave factor.

  7. Ultrasensitive ultrasonic transducer studies

    SciTech Connect

    Dixon, R.; Darling, T.; Migliori, A.

    1996-09-01

    This is the final report of a one-year, Laboratory-Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). This project sought to continue development of the ultrasensitive ultrasonic transducers that won a 1994 R&D 100 Award. These transducers have a very smooth response across a broad frequency range and thus are extremely well- suited for resonant ultrasound spectroscopy as well as pulsed-echo and acoustic-emission applications. Current work on these transducers has indicated that bonding the piezoelectric and wear surface to a metal foil and attaching the foil to a body is less expensive and produces a transducer that is as good or better than commercially produced transducers. We have diffusion- bonded piezoelectric crystals and backings to stainless-steel-foil and wear surfaces. These are then attached onto stainless-steel tubes with electrical connectors to form the transducers. The transducers have been characterized using a reciprocity technique, electrical response, and optical interferometry. After characterization, the transducers have been compared to existing transducers by measuring and testing identical properties.

  8. Controlled-Shape, Ultrasonic-Angle-Beam Standard Reflector

    NASA Technical Reports Server (NTRS)

    Berry, J., Robertf.

    1986-01-01

    New ultrasonic angle-beam standard reflector uses impression of letter "l" steel-die stamp. NDE techniques and standard reflector apply to use of pulse-echo-type ultrasonic equipment for inspection of wrought metals including forgings and forging stock; rolled billet, bar or plate; and extruded bar, tube, and shapes. "l" reference standard reflector affords advantages of easy insertion in inspected item using common hand-tools and greatly reduced implementation time through elimination of machining operations.

  9. Measurement of intergranular attack in stainless steel using ultrasonic energy

    DOEpatents

    Mott, Gerry; Attaar, Mustan; Rishel, Rick D.

    1989-08-08

    Ultrasonic test methods are used to measure the depth of intergranular attack (IGA) in a stainless steel specimen. The ultrasonic test methods include a pitch-catch surface wave technique and a through-wall pulse-echo technique. When used in combination, these techniques can establish the extent of IGA on both the front and back surfaces of a stainless steel specimen from measurements made on only one surface.

  10. Generation of extreme ultrasonics in rainforest katydids.

    PubMed

    Montealegre-Z, Fernando; Morris, Glenn K; Mason, Andrew C

    2006-12-01

    The calling song of an undescribed Meconematinae katydid (Tettigoniidae) from South America consists of trains of short, separated pure-tone sound pulses at 129 kHz (the highest calling note produced by an Arthropod). Paradoxically, these extremely high-frequency sound waves are produced by a low-velocity movement of the stridulatory forewings. Sound production during a wing stroke is pulsed, but the wings do not pause in their closing, requiring that the scraper, in its travel along the file, must do so to create the pulses. We hypothesize that during scraper pauses, the cuticle behind the scraper is bent by the ongoing relative displacement of the wings, storing deformation energy. When the scraper slips free it unbends while being carried along the file and its deformation energy contributes to a more powerful, higher-rate, one-tooth one-wave sound pulse, lasting no more than a few waves at 129 000 Hz. Some other katydid species make pure-tone ultrasonic pulses. Wing velocities and carriers among these pure-tone species fall into two groups: (1) species with ultrasonic carriers below 40 kHz that have higher calling frequencies correlated with higher wing-closing velocities and higher tooth densities: for these katydids the relationship between average tooth strike rate and song frequency approaches 1:1, as in cricket escapement mechanisms; (2) a group of species with ultrasonic carriers above 40 kHz (that includes the Meconematinae): for these katydids closing wing velocities are dramatically lower and they make short trains of pulses, with intervening periods of silence greater than the duration of the pulses they separate. This signal form may be the signature of scraper-stored elastic energy. PMID:17142681

  11. Investigating the effect of crack on propagation of ultrasonic guided waves in pipes via wavelet analysis

    NASA Astrophysics Data System (ADS)

    Riahi, Mohammad; Gholami, Pouya

    2016-04-01

    Ultrasonic guided waves have rapidly become an effective device in the field of NDT in recent years. Main reason for this is the ability of transmission from one point on the pipe to travel a long distance along it length. These waves are typically used in relatively low frequencies, and as a result, die out in longer periods of time. In this study, by designing and building a system to generate the needed signal for the stimulation of guided waves through using a piezoelectric crystal, these waves were generated and transmitted along a pipe. After propagation, waves were relieved by an ultrasonic probe and were saved by a digital oscilloscope. The received waves were then processed and filtered to eliminate noise and compared with each other. In order to compare the results and study the effective parameters of inspecting ability by these waves, the receiving probe was moved along the length of the pipe and through clanging the number of entering sinusoidal pulses along with altering the frequency signal; the data was recorded in the highest amplitude frequency. By adjusting the frequency within 30-40 KHz range, it would be possible to receive signals at any point in the experiment. Although the received signals weaken by further distance, however; through increase in the number of pulses of inlet signals, the guided waves better stimulate and become stronger at the outlet signal.

  12. Ultrasonic determination of Young's moduli of the coat and core materials of a drug tablet.

    PubMed

    Akseli, Ilgaz; Becker, Douglas C; Cetinkaya, Cetin

    2009-03-31

    Many modern tablet presses have system controls that monitor the force exerted to compress the solid oral dosage forms; however this data provides only limited information about the mechanical state of the tablet due to various process and materials uncertainties. A contact pulse/echo ultrasonic scheme is presented for the determination of the local Young's moduli of the coat and the core materials of enteric-coated and monolayer coated tablets. The Young's modulus of a material compacted into solid dosage can be related to its mechanical hardness and, consequently, its dissolution rate. In the current approach, short ultrasonic pulses are generated by the active element of a delay line transducer and are launched into the tablet. The waveforms reflected from the tablet coat-core interface are captured by the same transducer and are processed for determining the reflection and transmission coefficients of the interface from partially overlapping echoes. The Young's moduli of the coat and the core materials are then extracted from these coefficients. The results are compared to those obtained by an air-coupled acoustic excitation study, and good agreement is found. The described measurement technique provides greater insight into the local physical properties of the solid oral dosage form and, as a result, has the potential to provide better hardness-related performance predictability of compacts. PMID:19059326

  13. [Ultrasonic study of nucleic acids. Effect of pH].

    PubMed

    Braginskaia, F I; Sadykhova, S Kh

    1979-01-01

    The ultrasonic absorption of nucleic acids in water solutions was studied by the pulse ultrasonic technique depending on pH, at frequency 12 mHz T = 20 dedrees C. The obtained data show the occurrence of structural relaxation in DNA solutions caused by the proton exchange and transfer reactions with the extremal pH at 2.5 and 11.7. Possible mechanisms of the excess ultrasonic absorption were discussed concerning the protolytic processes with the charged DNA groups (N--P1 exchange and the hydrolysis of lactam groups at acid and alkaline pH correspondingly). PMID:36177

  14. Low-frequency three-dimensional ultrasonic tomography

    NASA Astrophysics Data System (ADS)

    Goncharsky, A. V.; Romanov, S. Yu.; Seryozhnikov, S. Yu.

    2016-05-01

    The possibility of making ultrasonic 3D tomographs for medical diagnostics of soft tissues was established. The choice of frequencies of ultrasonic pulses of 300-500 kHz was due to low absorption in soft tissues within this range. The reverse problems of ultrasonic tomography, which are three-dimensional and nonlinear, have been considered in a model that takes into account both wave effects and absorption. The effectiveness of algorithms to solve the reverse problems that were developed has been illustrated by model calculations. The velocity configuration has been shown to be recovered better than the function that describes absorption in soft tissues.

  15. Nondegenerate optical parametric chirped pulse amplifier

    DOEpatents

    Jovanovic, Igor; Ebbers, Christopher A.

    2005-03-22

    A system provides an input pump pulse and a signal pulse. A first dichroic beamsplitter is highly reflective for the input signal pulse and highly transmissive for the input pump pulse. A first optical parametric amplifier nonlinear crystal transfers part of the energy from the input pump pulse to the input signal pulse resulting in a first amplified signal pulse and a first depleted pump pulse. A second dichroic beamsplitter is highly reflective for the first amplified signal pulse and highly transmissive for the first depleted pump pulse. A second optical parametric amplifier nonlinear crystal transfers part of the energy from the first depleted pump pulse to the first amplified signal pulse resulting in a second amplified signal pulse and a second depleted pump pulse. A third dichroic beamsplitter receives the second amplified signal pulse and the second depleted pump pulse. The second depleted pump pulse is discarded.

  16. Ultrasonic Nondestructive Characterization of Adhesive Bonds

    NASA Technical Reports Server (NTRS)

    Qu, Jianmin

    1999-01-01

    interface binding force, a quantitative method was presented. Recently, a comparison between the experimental and simulated results based on a similar theoretical model was presented. A through-transmission setup for water immersion mode-converted shear waves was used to analyze the ultrasonic nonlinear parameter of an adhesive bond. In addition, ultrasonic guided waves have been used to analyze adhesive or diffusion bonded joints. In this paper, the ultrasonic nonlinear parameter is used to characterize the curing state of a polymer/aluminum adhesive joint. Ultrasonic through-transmission tests were conducted on samples cured under various conditions. The magnitude of the second order harmonic was measured and the corresponding ultrasonic nonlinear parameter was evaluated. A fairly good correlation between the curing condition and the nonlinear parameter is observed. The results show that the nonlinear parameter might be used as a good indicator of the cure state for adhesive joints.

  17. Wedges for ultrasonic inspection

    DOEpatents

    Gavin, Donald A.

    1982-01-01

    An ultrasonic transducer device is provided which is used in ultrasonic inspection of the material surrounding a threaded hole and which comprises a wedge of plastic or the like including a curved threaded surface adapted to be screwed into the threaded hole and a generally planar surface on which a conventional ultrasonic transducer is mounted. The plastic wedge can be rotated within the threaded hole to inspect for flaws in the material surrounding the threaded hole.

  18. Electrical pulse generator

    DOEpatents

    Norris, Neil J.

    1979-01-01

    A technique for generating high-voltage, wide dynamic range, shaped electrical pulses in the nanosecond range. Two transmission lines are coupled together by resistive elements distributed along the length of the lines. The conductance of each coupling resistive element as a function of its position along the line is selected to produce the desired pulse shape in the output line when an easily produced pulse, such as a step function pulse, is applied to the input line.

  19. The power of ultrasonics.

    PubMed

    Profit, Alan L; Martini, Luigi G

    2005-01-01

    This overview of ultrasonic technologies describes their effectiveness for a number of applications. Product examples illustrate use for welding, cutting and boring as well as atomising. PMID:16334603

  20. Ultrasonic Bolt Gage

    NASA Technical Reports Server (NTRS)

    Gleman, Stuart M. (Inventor); Rowe, Geoffrey K. (Inventor)

    1999-01-01

    An ultrasonic bolt gage is described which uses a crosscorrelation algorithm to determine a tension applied to a fastener, such as a bolt. The cross-correlation analysis is preferably performed using a processor operating on a series of captured ultrasonic echo waveforms. The ultrasonic bolt gage is further described as using the captured ultrasonic echo waveforms to perform additional modes of analysis, such as feature recognition. Multiple tension data outputs, therefore, can be obtained from a single data acquisition for increased measurement reliability. In addition, one embodiment of the gage has been described as multi-channel, having a multiplexer for performing a tension analysis on one of a plurality of bolts.

  1. High resolution in situ ultrasonic corrosion monitor

    DOEpatents

    Grossman, R.J.

    1984-01-10

    An ultrasonic corrosion monitor is provided which produces an in situ measurement of the amount of corrosion of a monitoring zone or zones of an elongate probe placed in the corrosive environment. A monitoring zone is preferably formed between the end of the probe and the junction of the zone with a lead-in portion of the probe. Ultrasonic pulses are applied to the probe and a determination made of the time interval between pulses reflected from the end of the probe and the junction referred to, both when the probe is uncorroded and while it is corroding. Corresponding electrical signals are produced and a value for the normalized transit time delay derived from these time interval measurements is used to calculate the amount of corrosion.

  2. High resolution in situ ultrasonic corrosion monitor

    DOEpatents

    Grossman, Robert J.

    1985-01-01

    An ultrasonic corrosion monitor is provided which produces an in situ measurement of the amount of corrosion of a monitoring zone or zones of an elongate probe placed in the corrosive environment. A monitoring zone is preferably formed between the end of the probe and the junction of the zone with a lead-in portion of the probe. Ultrasonic pulses are applied to the probe and a determination made of the time interval between pulses reflected from the end of the probe and the junction referred to, both when the probe is uncorroded and while it is corroding. Corresponding electrical signals are produced and a value for the normalized transit time delay derived from these time interval measurements is used to calculate the amount of corrosion.

  3. Sparsely Sampled Phase-Insensitive Ultrasonic Transducer Arrays

    NASA Technical Reports Server (NTRS)

    Johnston, Patrick H.

    1992-01-01

    Three methods of interpretation of outputs from sparsely sampled two-dimensional array of receiving ultrasonic transducers used in transmission experiments investigated. Methods are: description of sampled beam in terms of first few spatial moments of sampled distribution of energy; use of signal-dependent cutoff to limit extent of effective receiver aperture; and use of spatial interpolation to increase apparent density of sampling during computation. Methods reduce errors in computations of shapes of ultrasonic beams.

  4. Continuous Ultrasonic Inspection of Extruded Wood-Plastic Composites

    SciTech Connect

    Tucker, Brian J. ); Bender, Donald A.

    2003-06-19

    Nondestructive evaluation (NDE) techniques are needed for in-line monitoring of wood-plastic composite (WPC) quality during manufacturing for process control. Through-transmission ultrasonic inspection is useful in characterizing stiffness and detecting cracks and voids in a range of materials; however, little is documented about ultrasound propagation in WPC materials. The objectives of this research were to determine applicable ultrasonic transducer frequencies, coupling methods, configurations and placements for wave speed monitoring and web defect detection within an extrusion process; to quantify the effects of temperature on ultrasonic parameters; and to develop a prototype ultrasonic inspection system for a full-size extrusion line. An angled beam, water-coupled ultrasonic inspection system using a pair of 50-kHz narrowband transducers was adequate for monitoring wave speed parallel to the extrusion direction. For locating internal web defects, water-coupled, 500-kHz broadband ultrasonic transducers were used in a through-thickness transmission setup. Temperature compensation factors were developed to adjust ultrasonic wave speed measurements. The prototype inspection system was demonstrated in a 55 mm conical twin-screw extrusion line.

  5. The characteristics of novel bimodal Ag-TiO2 nanoparticles generated by hybrid laser-ultrasonic technique

    NASA Astrophysics Data System (ADS)

    Hamad, Abubaker; Li, Lin; Liu, Zhu; Zhong, Xiang Li; Burke, Grace; Wang, Tao

    2016-04-01

    Silver-titania (Ag-TiO2) nanoparticles with smaller Ag nanoparticles attached to larger TiO2 nanoparticles were generated by hybrid ultrasonic vibration and picosecond laser ablation of Ag and Ti bulk targets in deionised water, for the first time. The laser has a wavelength of 1064 nm and a pulse duration of 10 ps. It was observed that without the ultrasonic vibration, Ag and TiO2 nanoparticles did not combine, thus the role of ultrasonic vibration is essential. In addition, colloidal TiO2 and Ag nanoparticles were generated separately for comparison under the same laser beam characteristics and process conditions. The absorption spectra of colloidal Ag-TiO2 cluster nanoparticles were examined by UV-Vis spectroscopy, and size distribution was characterised using transmission electron microscopy. The morphology and composition of Ag-TiO2 nanoparticles were examined using scanning transmission electron microscopy in high-angle annular dark field, and energy-dispersive X-ray spectroscopy. The crystalline structures were investigated by X-ray diffraction. The size of larger TiO2 particles was in the range 30-150 nm, and the smaller-sized Ag nanoparticles attached to the TiO2 was mainly in the range of 10-15 nm. The yield is more than 50 % with the remaining nanoparticles in the form of uncombined Ag and TiO2. The nanoparticles generated had strong antibacterial effects as tested against E. coli. A discussion is given on the role of ultrasonic vibration in the formation of Ag-TiO2 hybrid nanoparticles by picosecond laser ablation.

  6. Pulse stretcher

    DOEpatents

    Horton, James A.

    1994-01-01

    Apparatus (20) for increasing the length of a laser pulse to reduce its peak power without substantial loss in the average power of the pulse. The apparatus (20) uses a White cell (10) having a plurality of optical delay paths (18a-18d) of successively increasing number of passes between the field mirror (13) and the objective mirrors (11 and 12). A pulse (26) from a laser (27) travels through a multi-leg reflective path (28) between a beam splitter (21) and a totally reflective mirror (24) to the laser output (37). The laser pulse (26) is also simultaneously injected through the beam splitter (21) to the input mirrors (14a-14d) of the optical delay paths (18a-18d). The pulses from the output mirrors (16a-16d) of the optical delay paths (18a-18d) go simultaneously to the laser output (37) and to the input mirrors ( 14b-14d) of the longer optical delay paths. The beam splitter (21) is 50% reflective and 50% transmissive to provide equal attenuation of all of the pulses at the laser output (37).

  7. Ultrasonic Inspection Of The LTAB Floor

    SciTech Connect

    Thomas, G

    2001-07-31

    The National Ignition Facility's (NIF) floor is damaged by transporter operations. Two basic operations, rotating the wheels in place and traversing the floor numerous times can cause failure in the grout layer. The floor is composed of top wear surface (Stonhard) and an osmotic grout layer on top of concrete, Fig. 1. An ultrasonic technique was implemented to assess the condition of the floor as part of a study to determine the damage mechanisms. The study considered damage scenarios and ways to avoid the damage. A possible solution is to install thin steel plates where the transporter traverses on the floor. These tests were conducted with a fully loaded transporter that applies up to 1300 psi loads to the floor. A contact ultrasonic technique evaluated the condition of the grout layer in NIF's floor. Figure 1 displays the configuration of the ultrasonic transducer on the floor. We inspected the floor after wheel rotation damage and after wheel traversal damage. Figure 2a and 2b are photographs of the portable ultrasonic system and data acquisition. We acquired ultrasonic signals in a known pristine area and a damaged area to calibrate the inspection. Figure 3 is a plot of the typical ultrasonic response from an undamaged area (black) overlapped with a signal (red) from a damaged area. The damage area data was acquired at a location next to a hole in the floor that was caused by the transporter. Five megahertz pulses are propagated from the transducer and through a Plexiglas buffer rod into the floor. The ultrasonic pulse reflects from each discontinuity in the floor. The ultrasonic signal reflects from the top surface, the Stonhard-to-grout interface, and the grout to concrete interface. We expect to see reflections from each of these interfaces in an undamaged floor. If the grout layer pulverizes then the high frequency signal cannot traverse the layer and the grout to concrete interface signal will decrease or vanish. The more damage to the grout the more the

  8. Dispersion Method Using Focused Ultrasonic Field

    NASA Astrophysics Data System (ADS)

    Kim, Jungsoon; Kim, Moojoon; Ha, Kanglyel; Chu, Minchul

    2010-07-01

    The dispersion of powders into liquids has become one of the most important techniques in high-tech industries and it is a common process in the formulation of various products, such as paint, ink, shampoo, beverages, and polishing media. In this study, an ultrasonic system with a cylindrical transducer is newly introduced for pure nanoparticle dispersion. The acoustics pressure field and the characteristics of the shock pulse caused by cavitation are investigated. The frequency spectrum of the pulse from the collapse of air bubbles in the cavitation is analyzed theoretically. It was confirmed that a TiO2 water suspension can be dispersed effectively using the suggested system.

  9. The 2004 Ultrasonic Benchmark Problem - SDH Response Under Oblique Incidence: Measurements and Patch Element Model Calculations

    SciTech Connect

    Krishnamurthy, C. V.; Shankar, M.; Vardhan, J. Vishnu; Balasubramaniam, Krishnan

    2006-03-06

    The 2004 ultrasonic benchmark problem requires models to predict, given a reference pulse waveform, the pulse echo response of cylindrical voids of various radii located in an elastic solid for various incidence angles of a transducer immersed in water. We present the results of calculations based on the patch element model, recently developed at CNDE, to determine the response of an SDH in aluminum for specific oblique incidence angles. Patch element model calculations for a scan across the SDH, involving a range of oblique incidence angles, are also presented. Measured pulse-echo scans involving the SDH response under oblique incidence conditions are reported. In addition, through transmission measurements involving a pinducer as a receiver and an immersion planar probe as a transmitter under oblique incidence conditions are also reported in a defect-free Aluminum block. These pinducer-based measurements on a defect-free block are utilised to characterize the fields at the chosen depth. Comparisons are made between predictions and measurements for the pulse-echo response of a SDH.

  10. An ultrasonic method for studying elastic moduli as a function of temperature

    NASA Technical Reports Server (NTRS)

    Peterson, R. G.

    1969-01-01

    Ultrasonic method is used to determine the elastic moduli of materials used in components of high-temperature nuclear reactors. An ultrasonic, pulse-echo technique determines the velocity of sound waves propogating in a heated region of rod-shaped specimens. From these velocities, the elastic moduli are calculated.

  11. Ultrasonic techniques for imaging and measurements in molten aluminum.

    PubMed

    Ono, Yuu; Moisan, Jean-François; Jen, Cheng-Kuei

    2003-12-01

    In order to achieve net shape forming, processing of aluminum (Al) in the molten state is often necessary. However, few sensors and techniques have been reported in the literature due to difficulties associated with molten Al, such as high temperature, corrosiveness, and opaqueness. In this paper, development of ultrasonic techniques for imaging and measurements in molten Al using buffer rods operated at 10 MHz is presented. The probing end of the buffer rod, having a flat surface or an ultrasonic lens, was immersed into molten Al while the other end with an ultrasonic transducer was air-cooled to room temperature. An ultrasonic image of a character "N", engraved on a stainless steel plate immersed in molten Al, and its corrosion have been observed at 780 degrees C using the focused probe in ultrasonic pulse-echo mode. Because cleanliness of molten Al is crucial for part manufacturing and recycling in Al processing, inclusion detection experiments also were carried out using the nonfocused probe in pitch-catch and pulse-echo modes. Backscattered ultrasonic signals from manually added silicon carbide particles, with an average diameter of 50 microm, in molten Al have been successfully observed at 780 degrees C. For optimal image quality, the spatial resolution of the focused probe was crucial, and the high signal-to-noise ratio of the nonfocused probe was the prime factor responsible for the inclusion detection sensitivity using backscattered ultrasonic signals. In addition, it was found that ultrasound could provide an alternative method for evaluating the degree of wetting between a solid material and a molten metal. Our experimental results showed that there was no ultrasonic coupling at the interface between an alumina rod and molten Al up to 1000 degrees C; therefore, no wetting existed at this interface. Also because ultrasonic velocity in alumina is temperature dependent, this rod proved to be able to be used as an in-line temperature monitoring sensor under

  12. Ultrasonic/Sonic Anchor

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph; Sherrit, Stewart

    2009-01-01

    The ultrasonic/sonic anchor (U/S anchor) is an anchoring device that drills a hole for itself in rock, concrete, or other similar material. The U/S anchor is a recent addition to a series of related devices, the first of which were reported in "Ultrasonic/Sonic Drill/Corers With Integrated Sensors"

  13. Ultrasonic measurement apparatus

    SciTech Connect

    Orban, J.; Mayes, J.C.

    1992-07-14

    This patent describes borehole measurement apparatus. It comprises a tool adapted for connection in a drill string in the borehole through earth formations, first and second ultra-sonic transmitter means disposed diametrically opposed from each other in the cylindrical body, first and second ultra-sonic transducer means disposed in the cylindrical body, and logic means, processing means, and memory means.

  14. Ultrasonic Communication Project, Phase 1, FY1999

    SciTech Connect

    Haynes, H.D.; Akerman, M.A.; Baylor, V.M.

    2000-06-01

    This Phase 1 project has been successful in identifying, exploring, and demonstrating methods for ultrasonic-based communication with an emphasis on the application of digital signal processing techniques. During the project, at the direction of the agency project monitor, particular attention was directed at sending and receiving ultrasonic data through air and through pipes that would be commonly found in buildings. Efforts were also focused on development of a method for transmitting computer files ultrasonically. New methods were identified and evaluated for ultrasonic communication. These methods are based on a technique called DFS. With DFS, individual alphanumeric characters are broken down into a sequence of bits, and each bit is used to generate a discrete ultrasonic frequency. Characters are then transmitted one-bit-at-a-time, and reconstructed by the receiver. This technique was put into practice through the development of LabVIEW{trademark}VIs. These VIs were integrated with specially developed electronic circuits to provide a system for demonstrating the transmission and reception/reconstruction of typed messages and computer files. Tests were performed to determine the envelope for ultrasound transmission through pipes (with and without water) versus through air. The practical aspects of connections, efficient electronics, impedance matching, and the effect of damping mechanisms were all investigated. These tests resulted in a considerable number of reference charts that illustrate the absorption of ultrasound through different pipe materials, both with and without water, as a function of distance. Ultrasound was found to be least attenuated by copper pipe and most attenuated by PVC pipe. Water in the pipe provides additional damping and attenuation of ultrasonic signals. Dramatic improvements are observed, however, in ultrasound signal strength if the transducers are directly coupled to the water, rather than simply attaching them to the outside of

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

    PubMed

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

    2013-06-01

    Inductive coupling offers a simple solution to wirelessly probe ultrasonic transducers. This paper investigates the theory and feasibility of such an inductively coupled transducer system in the context of nondestructive evaluation (NDE) applications. The noncontact interface is based on electromagnetic coupling between three coils; one of the coils is physically connected to the transducer, the other two are in a separate probing unit, where they are connected to the transmit and receive channels of the instrumentation. The complete system is modeled as a three-port network with the measured impedance of a bonded piezoelectric ceramic disc representing a sensor attached to an arbitrary solid substrate. The developed transmission line model is a function of the physical parameters of the electromagnetic system, such as the number of turns and diameter of each coil, and their separation. This model provides immediate predictions of electrical input impedance and pulse-echo response. The model has been validated experimentally and a sensitivity analysis of the input parameters performed. This has enabled optimization of the various parameters. Inductively coupled transducer systems have been built for both bulk and guided wave examples. By using chirped excitation and baseline subtraction, inspection distance of up to 700 mm is achieved in single-shot, guided-wave pulse-echo mode measurements with a 5 mm separation between the probing coils and transducer coil on an aluminum plate structure. In the bulk wave example, a delamination in an 8.9-mm-thick carbon fiber composite specimen is successfully identified from the changes in the arrival time of a reflected pulse. PMID:25004474

  16. Ultrasonic properties of granular media saturated with DNAPL/water mixtures

    NASA Astrophysics Data System (ADS)

    Ajo-Franklin, J. B.; Geller, J. T.; Harris, J. M.

    2007-04-01

    We present the results of four experiments investigating the ultrasonic properties of granular materials partially saturated with trichloroethylene (TCE), a dense non-aqueous contaminant. P-wave velocity measurements were made under in situ effective stress conditions using a pulse transmission cell at ~250 kHz. Two synthetic samples and two natural aquifer cores were fully saturated with water and then subjected to an axial injection of TCE. The resulting measurements show reductions in P-wave velocity of up to 15% due to contaminant saturation. A theoretical model combining Gassmann fluid substitution and Hill's equation was used to estimate the effects of DNAPL saturation; this model underpredicted observed reductions in velocity at high TCE saturations. A linear relationship, expressed in terms of volumetric contaminant fraction, provided an excellent empirical fit to the laboratory measurements.

  17. Proposal for an Ultrasonic Tool to Monitor the Osseointegration of Dental Implants

    PubMed Central

    de Almeida, Marina Storani; Maciel, Carlos Dias; Pereira, José Carlos

    2007-01-01

    The longevity of dental implants depends on osseointegration, which provides load-bearing capacity without putting the prosthesis at risk from micromotions at the implant-bone interface. This research involved an analysis of the viability of an ultrasonic evaluation tool to quantify osseointegration. Ultrasonic transmission is directly dependent on the difference between the acoustic impedance of materials in intimate contact with each other. The closer their acoustic impedances the more intense their transmission. Therefore, an analysis of the ultrasonic echoes would presumably allow for a quantitative evaluation of the bone tissue that has grown into the pores of the implant. In addition, the literature reports that bone fracture healing can be accelerated by the application of a controlled low-amplitude mechanical stimulus on the site of the lesion. In fact, acoustic pressure waves of low-intensity pulsed ultrasound are reportedly a secure technique for promoting mechanical stimulus without impairing the healing process. Many experimental and clinical trials have confirmed that daily transcutaneous ultrasound applications on the injured site are beneficial to the enhancement of fractured bone. This proposal aims to bring together the characteristics of ultrasound propagation and the positive effect of ultrasound on bone growth into a single tool that quantitatively monitors the evolution of the osseointegration process. The viability of a device with these features was investigated through simulations and experimentally. The initial simulations were conducted to explore the influence of waveguide shapes on the tool's sensitivity to changes in the implant supporting media. The waveguides were designed in two parts, one consisting of a screw-shaped part to attach to the implant and the other a conical or step-shaped part to which the ultrasonic source was fixed in the first simulations. The step-shaped waveguide proved to be the more sensitive; intermediate stages

  18. Ultrasonic evaluation of the physical and mechanical properties of granites.

    PubMed

    Vasconcelos, G; Lourenço, P B; Alves, C A S; Pamplona, J

    2008-09-01

    Masonry is the oldest building material that survived until today, being used all over the world and being present in the most impressive historical structures as an evidence of spirit of enterprise of ancient cultures. Conservation, rehabilitation and strengthening of the built heritage and protection of human lives are clear demands of modern societies. In this process, the use of nondestructive methods has become much common in the diagnosis of structural integrity of masonry elements. With respect to the evaluation of the stone condition, the ultrasonic pulse velocity is a simple and economical tool. Thus, the central issue of the present paper concerns the evaluation of the suitability of the ultrasonic pulse velocity method for describing the mechanical and physical properties of granites (range size between 0.1-4.0 mm and 0.3-16.5 mm) and for the assessment of its weathering state. The mechanical properties encompass the compressive and tensile strength and modulus of elasticity, and the physical properties include the density and porosity. For this purpose, measurements of the longitudinal ultrasonic pulse velocity with distinct natural frequency of the transducers were carried out on specimens with different size and shape. A discussion of the factors that induce variations on the ultrasonic velocity is also provided. Additionally, statistical correlations between ultrasonic pulse velocity and mechanical and physical properties of granites are presented and discussed. The major output of the work is the confirmation that ultrasonic pulse velocity can be effectively used as a simple and economical nondestructive method for a preliminary prediction of mechanical and physical properties, as well as a tool for the assessment of the weathering changes of granites that occur during the serviceable life. This is of much interest due to the usual difficulties in removing specimens for mechanical characterization. PMID:18471849

  19. Ultrasonic assessment of tooth structure

    NASA Astrophysics Data System (ADS)

    Blodgett, David W.

    2002-06-01

    A means of assessing the internal structure of teeth based upon use of high frequency, highly localized ultrasound (acoustic waves) generated by a short laser pulse is discussed. Some key advantages of laser-generated ultrasound over more traditional contact transducer methods are that it is noncontact and nondestructive in nature and requires no special surface preparation. Optical interferometric detection of ultrasound provides a complementary nondestructive, noncontact technique with a very small detection footprint. This combination of techniques, termed laser-based ultrasonics, holds promise for future in-vivo diagnostics of tooth health. In this paper, initial results using laser-based ultrasound for assessment of dental structures are presented on an extracted human incisor. Results show the technique to be sensitive to the enamel/dentin, dentin/pulp, and dentin/cementum junctions as well as a region of dead tracts in the dentin.

  20. Diver monitoring by ultrasonic digital data telemetry.

    PubMed

    Woodward, B; Bateman, S C

    1994-07-01

    A through-water ultrasonic data telemetry system using burst-mode frequency shift keying (FSK) is described. The system can be adapted for the transmission of data from various sensors, but it has been designed principally for monitoring the respiratory rate, heart rate, temperature and depth of a free-swimming diver over a range of up to 300 metres. This application requires the transmission of low rate digital signals through water from a moving source to a receiver that is either stationary or moving. PMID:7952660

  1. Structure and properties of fixed joints formed by ultrasonic-assisted friction-stir welding

    NASA Astrophysics Data System (ADS)

    Fortuna, S. V.; Ivanov, K. V.; Tarasov, S. Yu.; Eliseev, A. A.; Ivanov, A. N.; Rubtsov, V. E.; Kolubaev, E. A.

    2015-10-01

    This paper deals with structure and properties of aluminum alloy 7475 and its joints obtained by friction stir welding including under ultrasonic action. Microhardness measurements show that ultrasonic action increases strength properties of the joints. Optical and transmission electron microscopy reveals that this effect is related to the precipitation of tertiary coherent S-and T-phase particles.

  2. Structure and properties of fixed joints formed by ultrasonic-assisted friction-stir welding

    SciTech Connect

    Fortuna, S. V. Ivanov, K. V. Eliseev, A. A.; Tarasov, S. Yu. Ivanov, A. N. Rubtsov, V. E. Kolubaev, E. A.

    2015-10-27

    This paper deals with structure and properties of aluminum alloy 7475 and its joints obtained by friction stir welding including under ultrasonic action. Microhardness measurements show that ultrasonic action increases strength properties of the joints. Optical and transmission electron microscopy reveals that this effect is related to the precipitation of tertiary coherent S-and T-phase particles.

  3. Measurement of the spectral directivity of optoacoustic and ultrasonic transducers with a laser ultrasonic source

    PubMed Central

    Conjusteau, André; Ermilov, Sergey A.; Su, Richard; Brecht, Hans-Peter; Fronheiser, Matthew P.; Oraevsky, Alexander A.

    2009-01-01

    Comprehensive characterization of wideband ultrasonic transducers and specifically optoacoustic detectors is achieved through the analysis of their frequency response as a function of the incident angle. The tests are performed under well-defined, repeatable operating conditions. Backillumination of a blackened, acoustically matched planar surface with a short laser pulse creates an acoustic impulse which is used as a wideband ultrasonic source. Upon illumination with a short laser pulse, the bandwidth of our source shows a −6 dB point of 12 MHz and a low-frequency roll-off around 300 kHz. Using proprietary software, we examine thoroughly the planarity of the emitted wave front within a specified amplitude cutoff and phase incoherence. Analysis of the angular dependence of the frequency response yields invaluable directivity information about the detector under study: a necessary component toward accurate optoacoustic image reconstruction and quantitative tomography. The laser ultrasonic source we developed is the main feature of our directivity measurement setup. Due to its simplicity, it can easily be adapted to various calibration devices. This paper focuses on the development and characterization of the flatness and the bandwidth of our wideband ultrasonic source. PMID:19791945

  4. PULSE AMPLITUDE ANALYZER

    DOEpatents

    Gray, G.W.; Jensen, A.S.

    1957-10-22

    A pulse-height analyzer system of improved design for sorting and counting a series of pulses, such as provided by a scintillation detector in nuclear radiation measurements, is described. The analyzer comprises a main transmission line, a cathode-ray tube for each section of the line with its deflection plates acting as the line capacitance; means to bias the respective cathode ray tubes so that the beam strikes a target only when a prearranged pulse amplitude is applied, with each tube progressively biased to respond to smaller amplitudes; pulse generating and counting means associated with each tube to respond when the beam is deflected; a control transmission line having the same time constant as the first line per section with pulse generating means for each tube for initiating a pulse on the second transmission line when a pulse triggers the tube of corresponding amplitude response, the former pulse acting to prevent successive tubes from responding to the pulse under test. This arrangement permits greater deflection sensitivity in the cathode ray tube and overcomes many of the disadvantages of prior art pulse-height analyzer circuits.

  5. Detonator comprising a nonlinear transmission line

    SciTech Connect

    Elizondo-Decanini, Juan M

    2014-12-30

    Detonators are described herein. In a general embodiment, the detonator includes a nonlinear transmission line that has a variable capacitance. Capacitance of the nonlinear transmission line is a function of voltage on the nonlinear transmission line. The nonlinear transmission line receives a voltage pulse from a voltage source and compresses the voltage pulse to generate a trigger signal. Compressing the voltage pulse includes increasing amplitude of the voltage pulse and decreasing length of the voltage pulse in time. An igniter receives the trigger signal and detonates an explosive responsive to receipt of the trigger signal.

  6. Image measurement technique on vibration amplitude of ultrasonic horn

    NASA Astrophysics Data System (ADS)

    Zhang, Yong-bin; Wu, Zhi-qun; Zhu, Jian-ping; He, Jian-guo; Liu, Guang-min

    2013-10-01

    The paper proposes a method to measure vibration amplitude of ultrasonic horn which is a very important component in the spindle for micro-electrical-chemical discharging machining. The method of image measuring amplitude on high frequency vibration is introduced. Non-contact measurement system based on vision technology is constructed. High precision location algorithm on image centroid, quadratic location algorithm, is presented to find the center of little light spot. Measurement experiments have been done to show the effect of image measurement technique on vibration amplitude of ultrasonic horn. In the experiments, precise calibration of the vision system is implemented using a normal graticule to obtain the scale factor between image pixel and real distance. The vibration amplitude of ultrasonic horn is changed by modifying the voltage amplitude of pulse power supply. The image of feature on ultrasonic horn is captured and image processing is carried out. The vibration amplitudes are got at different voltages.

  7. Method for the concurrent ultrasonic inspection of partially completed welds

    DOEpatents

    Johnson, John A.; Larsen, Eric D.; Miller, Karen S.; Smartt, Herschel B.; McJunkin, Timothy R.

    2002-01-01

    A method for the concurrent ultrasonic inspection of partially completed welds is disclosed and which includes providing a pair of transducers which are individually positioned on the opposite sides of a partially completed weld to be inspected; moving the transducers along the length of and laterally inwardly and outwardly relative to the partially completed weld; pulsing the respective transducers to produce an ultrasonic signal which passes through or is reflected from the partially completed weld; receiving from the respective transducers ultrasonic signals which pass through or are reflected from the partially completed welds; and analyzing the ultrasonic signal which has passed through or is reflected from the partially completed weld to determine the presence of any weld defects.

  8. Air coupled ultrasonic detection of surface defects in food cans

    NASA Astrophysics Data System (ADS)

    Seco, Fernando; Ramón Jiménez, Antonio; del Castillo, María Dolores

    2006-06-01

    In this paper, we describe an ultrasonic inspection system used for detection of surface defects in food cans. The system operates in the pulse-echo mode and analyses the 220 kHz ultrasonic signal backscattered by the object. The classification of samples into valid or defective is achieved with χ2 statistics and the k nearest neighbour method, applied to features computed from the envelope of the ultrasonic echo. The performance of the system is demonstrated empirically in detection of the presence of the pull tab on the removable lid of easy-open food cans, in a production line. It is found that three factors limit the performance of the classification: the misalignment of the samples, their separation of the ultrasonic transducer, and the vibration of the conveyor belt. When these factors are controlled, classification success rates between 94% and 99% are achieved.

  9. Ultrasonic drilling apparatus

    DOEpatents

    Duran, E.L.; Lundin, R.L.

    1988-06-20

    Apparatus attachable to an ultrasonic drilling machine for drilling deep holes in very hard materials, such as boron carbide, is provided. The apparatus utilizes a hollow spindle attached to the output horn of the ultrasonic drilling machine. The spindle has a hollow drill bit attached at the opposite end. A housing surrounds the spindle, forming a cavity for holding slurry. In operation, slurry is provided into the housing, and into the spindle through inlets while the spindle is rotating and ultrasonically reciprocating. Slurry flows through the spindle and through the hollow drill bit to cleanse the cutting edge of the bit during a drilling operation. 3 figs.

  10. Ultrasonic Imaging System

    NASA Technical Reports Server (NTRS)

    Youngquist, Robert C. (Inventor); Moerk, Steven (Inventor)

    1999-01-01

    An imaging system is described which can be used to either passively search for sources of ultrasonics or as an active phase imaging system. which can image fires. gas leaks, or air temperature gradients. This system uses an array of ultrasonic receivers coupled to an ultrasound collector or lens to provide an electronic image of the ultrasound intensity in a selected angular region of space. A system is described which includes a video camera to provide a visual reference to a region being examined for ultrasonic signals.

  11. Ultrasonic washing of textiles.

    PubMed

    Choi, Junhee; Kim, Tae-Hong; Kim, Ho-Young; Kim, Wonjung

    2016-03-01

    We present the results of experimental investigation of ultrasonic washing of textiles. The results demonstrate that cavitation bubbles oscillating in acoustic fields are capable of removing soils from textiles. Since the washing performance is mitigated in a large washing bath when using an ultrasonic transducer, we propose a novel washing scheme by combining the ultrasonic vibration with a conventional washing method utilizing kinetic energy of textiles. It is shown that the hybrid washing scheme achieves a markedly enhanced performance up to 15% in comparison with the conventional washing machine. This work can contribute to developing a novel laundry machine with reduced washing time and waste water. PMID:26215790

  12. Ultrasonic liquid level detector

    DOEpatents

    Kotz, Dennis M.; Hinz, William R.

    2010-09-28

    An ultrasonic liquid level detector for use within a shielded container, the detector being tubular in shape with a chamber at its lower end into which liquid from in the container may enter and exit, the chamber having an ultrasonic transmitter and receiver in its top wall and a reflector plate or target as its bottom wall whereby when liquid fills the chamber a complete medium is then present through which an ultrasonic wave may be transmitted and reflected from the target thus signaling that the liquid is at chamber level.

  13. Ultrasonic drilling apparatus

    DOEpatents

    Duran, Edward L.; Lundin, Ralph L.

    1989-01-01

    Apparatus attachable to an ultrasonic drilling machine for drilling deep holes in very hard materials, such as boron carbide, is provided. The apparatus utilizes a hollow spindle attached to the output horn of the ultrasonic drilling machine. The spindle has a hollow drill bit attached at the opposite end. A housing surrounds the spindle, forming a cavity for holding slurry. In operation, slurry is provided into the housing, and into the spindle through inlets while the spindle is rotating and ultrasonically reciprocating. Slurry flows through the spindle and through the hollow drill bit to cleanse the cutting edge of the bit during a drilling operation.

  14. Ultrasonic testing of reactive powder concrete.

    PubMed

    Washer, Glenn; Fuchs, Paul; Graybeal, Benjamin A; Hartmann, Joseph Lawrence

    2004-02-01

    Concrete is a critical material for the construction of infrastructure facilities throughout the world. Traditional concretes consist of cement paste and aggregates ranging in size from 6 to 25 mm that form a heterogeneous material with substantial compressive strength and a very low tensile strength. Steel reinforcement is used to provide tensile strength for reinforced concrete structures and as a composite the material is useful for structural applications. A new material known as reactive powder concrete (RPC) is becoming available. It differs significantly from traditional concrete; RPC has no large aggregates, and contains small steel fibers that provide additional strength and, in some cases, can replace traditional steel reinforcement. Due to its high density and lack of aggregates, ultrasonic inspections at frequencies 10 to 20 times that of traditional concrete inspections are possible. This paper reports on the initial findings of research conducted to determine the applicability of ultrasonic testing techniques for the condition assessment of RPC. Pulse velocities for shear and longitudinal waves and ultrasonic measurement of the modulus of elasticity for RPC are reported. Ultrasonic crack detection for RPC also is investigated. PMID:15055809

  15. Photoconductive circuit element pulse generator

    DOEpatents

    Rauscher, Christen

    1989-01-01

    A pulse generator for characterizing semiconductor devices at millimeter wavelength frequencies where a photoconductive circuit element (PCE) is biased by a direct current voltage source and produces short electrical pulses when excited into conductance by short laser light pulses. The electrical pulses are electronically conditioned to improve the frequency related amplitude characteristics of the pulses which thereafter propagate along a transmission line to a device under test.

  16. Ultrasonic Digital Communication System for a Steel Wall Multipath Channel: Methods and Results

    SciTech Connect

    TL Murphy

    2006-02-16

    As of the development of this thesis, no commercially available products have been identified for the digital communication of instrumented data across a thick ({approx} 6 n.) steel wall using ultrasound. The specific goal of the current research is to investigate the application of methods for digital communication of instrumented data (i.e., temperature, voltage, etc.) across the wall of a steel pressure vessel. The acoustic transmission of data using ultrasonic transducers prevents the need to breach the wall of such a pressure vessel which could ultimately affect its safety or lifespan, or void the homogeneity of an experiment under test. Actual digital communication paradigms are introduced and implemented for the successful dissemination of data across such a wall utilizing solely an acoustic ultrasonic link. The first, dubbed the ''single-hop'' configuration, can communicate bursts of digital data one-way across the wall using the Differential Binary Phase-Shift Keying (DBPSK) modulation technique as fast as 500 bps. The second, dubbed the ''double-hop'' configuration, transmits a carrier into the vessel, modulates it, and retransmits it externally. Using a pulsed carrier with Pulse Amplitude Modulation (PAM), this technique can communicate digital data as fast as 500 bps. Using a CW carrier, Least Mean-Squared (LMS) adaptive interference suppression, and DBPSK, this method can communicate data as fast as 5 kbps. A third technique, dubbed the ''reflected-power'' configuration, communicates digital data by modulating a pulsed carrier by varying the acoustic impedance at the internal transducer-wall interface. The paradigms of the latter two configurations are believed to be unique. All modulation methods are based on the premise that the wall cannot be breached in any way and can therefore be viably implemented with power delivered wirelessly through the acoustic channel using ultrasound. Methods, results, and considerations for future research are discussed

  17. Effects of thin layer adherents on ultrasonic testing results

    NASA Astrophysics Data System (ADS)

    Johnson, E. C.; Hawkins, G. F.

    Results are reported of an experimental study tracing the effect of variations in the thickness of a thin adherent layer on the results of an ultrasonic pulse-echo test. The ray-tracing computer technique yielded values in excellent agreement with experiment especially when consideration is given to the complexity of the results. As the liquid thickness approached zero, the values produced by the computer model approached those expected for the dry condition even though the solid-air reflection coefficient was not used in the calculation. It is shown that the presence of a thin film on the surface of a material can drastically alter the amplitude of ultrasonic echoes within the material. Consequently, pulse-echo ultrasonic inspection techniques, which would otherwise work well, can be totally invalidated by slight variations in, for example, the thickness of a layer of paint.

  18. Three-dimensional imaging of biological cells with picosecond ultrasonics

    NASA Astrophysics Data System (ADS)

    Danworaphong, Sorasak; Tomoda, Motonobu; Matsumoto, Yuki; Matsuda, Osamu; Ohashi, Toshiro; Watanabe, Hiromu; Nagayama, Masafumi; Gohara, Kazutoshi; Otsuka, Paul H.; Wright, Oliver B.

    2015-04-01

    We use picosecond ultrasonics to image animal cells in vitro—a bovine aortic endothelial cell and a mouse adipose cell—fixed to Ti-coated sapphire. Tightly focused ultrashort laser pulses generate and detect GHz acoustic pulses, allowing three-dimensional imaging (x, y, and t) of the ultrasonic propagation in the cells with ˜1 μm lateral and ˜150 nm depth resolutions. Time-frequency representations of the continuous-wavelet-transform amplitude of the optical reflectivity variations inside and outside the cells show GHz Brillouin oscillations, allowing the average sound velocities of the cells and their ultrasonic attenuation to be obtained as well as the average bulk moduli.

  19. The application research of laser ultrasonic technique used in testing compound material

    NASA Astrophysics Data System (ADS)

    Xu, Jun; Kong, Lingjian; Gu, Xiaofei; Luo, Jijun; Hou, Xun

    2005-01-01

    The principles of laser ultrasonic generation and measurements with pulsed laser are presented. There are two kinds of means to actuate ultrasonic pulse: elasticity actuating and ablation actuating. The progress in laser ultrasonic about laser ultrasound generation, detection, propagation and its applications is introduced briefly. Applications in the field of Non-Destructive Testing (NDT) are reviewed. In the field of Non-Destructive Testing, according to the principle, the laser ultrasonic testing system consists of laser system, laser interferometer, photoelectric detector and receiving system with signal amplifier. Thus, long-range and non-contact on-line detection of ultrasonic testing system was realized. In view of some of the problems, the developing trends of such techniques are analyzed.

  20. Research on embedding invisible digital watermarking in ultrasonic image

    NASA Astrophysics Data System (ADS)

    Ye, Huashan; Shi, Qing; Ding, Mingyue

    2009-10-01

    In this paper, we proposed an adaptive watermarking algorithm to embed invisible digital watermarking in the wavelet domain of ultrasonic image. By analyzing the characteristic of detail sub-band coefficients of the ultrasonic image after discrete wavelet transform (DWT), we use the mean and variance of the detail sub-bands to modify the wavelet coefficients adaptively, and the embedded watermark is invisible to human visual system (HVS) and adapted to the original image. We can derive the just noticeable different (JND), which describes the maximum signal intensity that the various parts of image can tolerate the digital watermarking. By using this digital watermarking technique we can embed a certainty or confidentiality information directly into original ultrasonic images so that the replication and transmission of ultrasonic image can be tracked efficiently. Therefore, the copyright and ownership of ultrasonic images can be protected, which is critical for the authorization usage of the source of ultrasonic images. The experimental results and attack analysis showed that the proposed algorithm is effective and robust to ultrasonic image processing operations and geometric attacks.

  1. Ultrasonic material property determinations

    NASA Technical Reports Server (NTRS)

    Serabian, S.

    1986-01-01

    The use and potential offered by ultrasonic velocity and attenuation measurements to determine and/or monitor material properties is explored. The basis for such unique measurements along with examples of materials from a variety of industries are presented.

  2. Scanning electron microscopy and transmission electron microscopy microstructural investigation of high-speed tool steel after Nd:YAG pulsed laser melting.

    PubMed

    Kac, S; Kusinski, J; Zielinskalipiec, A; Wronska, I

    2006-10-01

    This article presents the microstructure of a pulsed Nd:YAG laser-melted high-speed steel, namely HS6-5-2. The high chemical homogeneity and fine structure of the melted zone was attributed to high cooling rates due to the short duration of interaction with the Nd:YAG pulsed laser radiation and the relatively small volume of the melted material. The structure obtained in the surface layer after laser melting has a high level of hardness and shows improved wear resistance. PMID:17100909

  3. PULSED INDICATOR CIRCUIT

    DOEpatents

    Linlor, W.I.; Kerns, Q.A.

    1960-11-15

    A system is given for detecting incremental changes in a transducer impedance terminating a transmission line. Principal novelty resides in the transducer impedance terminating the line in a mismatch and a pulse generator being provided to apply discrete pulses to the input end of the line. The amplitudes of the pulses reflected to the input end of the line from the mismatched transducer impedance are then observed as a very accurate measure of the instantaneous value of the latter.

  4. Laser ultrasonics: Current research needs

    SciTech Connect

    Wagner, J.W. . Center for Nondestructive Evaluation)

    1990-09-26

    Laser-ultrasonics refers to a range of technologies involving the use of laser electrooptical systems both to generate and to detect ultrasonic signals in and on materials and structures. Such systems have been developed to permit classical ultrasonic measurements for materials characterization and defect identification and measurement. From the point of view of one concerned with practical applications of ultrasonic inspection and measurement methods, laser-ultrasonic systems offer the flexibility which, in principle, should permit remote ultrasonic measurements to be performed on objects at elevated temperatures or in hostile environments. Laser-ultrasonic systems can be designed and constructed with extremely wide and flat detection bandwidth so that ultrasonic vibrational displacements can be recorded with high fidelity. In addition, there is no mechanical loading of the surface to damp, absorb, or otherwise distort the propagating acoustic energy. This feature has been used to great advantage in performing ultrasonic measurements in thin plates and films. In spite of the great advantages offered by laser-ultrasonics, there are severe limitations which restrict its application. In fact, based upon the performance of current state-of-the-art laser-ultrasonic systems, it is almost always more advantageous to use conventional ultrasonic transduction methods, if possible for a given application, than it is to apply laser-ultrasonics. In short, the main reason leading to this conclusion is the poor system detection sensitivity of laser-ultrasonic systems compared with piezoelectric transducer systems. The ramifications of this limited sensitivity are many.

  5. Laser ultrasonics in Brazil for aeronautics and space engineering

    NASA Astrophysics Data System (ADS)

    Salvi Sakamoto, João Marcos; Pacheco, Gefeson Mendes

    2010-01-01

    This work is a report bringing the experimental setup and the initial developments to establish a laser ultrasonics system at the Instituto Tecnológico de Aeronáutica in Brazil. Present-day development aim to substitute piezoelectric transducer by a high power pulsed laser to generate ultrasound.

  6. Testing Results of Magnetostrictive Ultrasonic Sensor Cables for Signal Loss

    SciTech Connect

    JT Evans

    2005-05-01

    The purpose of this test was to determine the signal strength and resolution losses of a magnetostrictive ultrasonic system with an extended signal cable. The cable of interest carries electrical signals between the pulse generator/receiver and the magnetostrictive transducer. It was desired to determine the loss introduced by different lengths of the signal cable (6', 100', and 200').

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

    PubMed

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

    2013-12-01

    Capacitive coupling offers a simple solution to wirelessly probe ultrasonic transducers. This paper investigates the theory, feasibility, and optimization of such a capacitively coupled transducer system (CCTS) in the context of nondestructive evaluation (NDE) applications. The noncontact interface relies on an electric field formed between four metal plates-two plates are physically connected to the electrodes of a transducer, the other two are in a separate probing unit connected to the transmit/receive channel of the instrumentation. The complete system is modeled as an electric network with the measured impedance of a bonded piezoelectric ceramic disc representing a transducer attached to an arbitrary solid substrate. A transmission line model is developed which is a function of the physical parameters of the capacitively coupled system, such as the permittivity of the material between the plates, the size of the metal plates, and their relative positions. This model provides immediate prediction of electric input impedance, pulse-echo response, and the effect of plate misalignment. The model has been validated experimentally and has enabled optimization of the various parameters. It is shown that placing a tuning inductor and series resistor on the transmitting side of the circuit can significantly improve the system performance in terms of the signal-to-crosstalk ratio. Practically, bulk-wave CCTSs have been built and demonstrated for underwater and through-composite testing. It has been found that electrical conduction in the media between the plates limits their applications. PMID:24297024

  8. Linear and Nonlinear Ultrasonic Properties of Granular Soils

    SciTech Connect

    Bonner, B.; Berge, P.A.; Aracne-Ruddle, C.M.; Bertete-Auguirre, H.; Wildenschild, D.; Trombino, C.N.; Hardy, E.

    2000-04-20

    The ultrasonic pulse transmission method (100-500 kHz) was adapted to measure compressional (P) and shear (S) wave velocities for synthetic soils fabricated from quartz-clay and quartz-peat mixtures. Velocities were determined as samples were loaded by small (up to 0.1 MPa) uniaxial stress to determine how stress at grain contacts affects ave amplitudes, velocities, and frequency content. Samples were fabricated from quartz sand mixed with either a swelling clay or peat (natural cellulose). P velocities in these dry synthetic soil samples were low, ranging from about 230 to 430 m/s for pure sand, about 91 to 420 m/s for sand-peat mixtures, and about 230 to 470 m/s for dry sand-clay mixtures. S velocities were about half of the P velocity in most cases, about 130 to 250 m/s for pure sand, about 75-220 m/s for sand-peat mixtures, and about 88-220 m/s for dry sand-clay mixtures. These experiments demonstrate that P and S velocities are sensitive to the amount and type of admixed second phase at low concentrations. They found that dramatic increases in all velocities occur with small uniaxial loads, indicating strong nonlinearity of the acoustic properties. Composition and grain packing contribute to the mechanical response at grain contacts and the nonlinear response at low stresses.

  9. Error-eliminating rapid ultrasonic firing

    DOEpatents

    Borenstein, J.; Koren, Y.

    1993-08-24

    A system for producing reliable navigation data for a mobile vehicle, such as a robot, combines multiple range samples to increase the confidence'' of the algorithm in the existence of an obstacle. At higher vehicle speed, it is crucial to sample each sensor quickly and repeatedly to gather multiple samples in time to avoid a collision. Erroneous data is rejected by delaying the issuance of an ultrasonic energy pulse by a predetermined wait-period, which may be different during alternate ultrasonic firing cycles. Consecutive readings are compared, and the corresponding data is rejected if the readings differ by more than a predetermined amount. The rejection rate for the data is monitored and the operating speed of the navigation system is reduced if the data rejection rate is increased. This is useful to distinguish and eliminate noise from the data which truly represents the existence of an article in the field of operation of the vehicle.

  10. Error-eliminating rapid ultrasonic firing

    DOEpatents

    Borenstein, Johann; Koren, Yoram

    1993-08-24

    A system for producing reliable navigation data for a mobile vehicle, such as a robot, combines multiple range samples to increase the "confidence" of the algorithm in the existence of an obstacle. At higher vehicle speed, it is crucial to sample each sensor quickly and repeatedly to gather multiple samples in time to avoid a collision. Erroneous data is rejected by delaying the issuance of an ultrasonic energy pulse by a predetermined wait-period, which may be different during alternate ultrasonic firing cycles. Consecutive readings are compared, and the corresponding data is rejected if the readings differ by more than a predetermined amount. The rejection rate for the data is monitored and the operating speed of the navigation system is reduced if the data rejection rate is increased. This is useful to distinguish and eliminate noise from the data which truly represents the existence of an article in the field of operation of the vehicle.

  11. Elastic properties of sand-peat moss mixtures from ultrasonic measurements

    SciTech Connect

    Trombino, C N

    1998-09-02

    Effective remediation of an environmental site requires extensive knowledge of the geologic setting, as well as the amount and distribution of contaminants. Seismic investigations provide a means to examine the subsurface with minimum disturbance, Laboratory measurements are needed to interpret field data. In this experiment, laboratory tests were performed to characterize manufactured soil samples in terms of their elastic properties. The soil samples consisted of small (mass) percentages (1 to 20 percent) of peat moss mixed with pure quartz sand. Sand was chosen as the major component because its elastic properties are well known except at the lowest pressures. The ultrasonic pulse transmission technique was used to collect elastic wave velocity data. These data were analyzed and mathematically processed to calculate the other elastic properties such as the modulus of elasticity. This experiment demonstrates that seismic data are affected by the amount~of peat moss added to pure sand samples. Elastic wave velocities, velocity gradients, and elastic moduli vary with pressure and peat moss amounts. In particular, ultrasonic response changes dramatically when pore space fills with peat. With some further investigation, the information gathered in this experiment could be applied to seismic field research.

  12. Reverberation Reduction in Capacitive Micromachined Ultrasonic Transducers (CMUTs) by Front-face Reflectivity Minimization

    NASA Astrophysics Data System (ADS)

    Savoia, Alessandro Stuart; La Mura, Monica; Mauti, Barbara; Lamberti, Nicola; Caliano, Giosuè

    Front-face acoustic reflectivity of ultrasonic imaging transducers, due to acoustic impedance mismatch with the propagation medium, may cause reverberation phenomena during wideband pulse-echo operation. Front-face reflectivity may be reduced by promoting the transmission of the echoes, received from the medium, to the transducer backing, and by maximizing the mechanical-to-electrical energy conversion and dissipation by tuning the electrical load impedance connected to the transducer. In Capacitive Micromachined Ultrasonic Transducers (CMUTs), the energy transfer from the medium to the backing is very low due to the large impedance mismatch between the medium and the transducer substrate, typically made of silicon. Reverse Fabrication Process (RFP) makes it possible providing CMUTs with custom substrate materials, thus eliminating the original silicon microfabrication support. In this paper, we propose two methods for the front-face reflectivity reduction in RFP-CMUTs: the first one is based on the use of low-impedance, highly attenuating backing materials, and the second one is based on the maximization of the mechanoelectrical energy conversion and dissipation. We analyze the methods by finite element simulations and experimentally validate the obtained results by fabricating and characterizing single-element RFP-CMUTs provided with different backing materials and electrical loads.

  13. Optimization of Focal Position of Ultrasonic Beam in Measurement of Small Change in Arterial Wall Thickness

    NASA Astrophysics Data System (ADS)

    Watanabe, Masaru; Kanai, Hiroshi

    2001-05-01

    We have previously developed a method for measurement of a small change in thickness of the arterial wall during a single cardiac cycle [H. Kanai, M. Sato, Y. Koiwa and N. Chubachi: IEEE Trans. UFFC 43 (1996) 791]. The resultant change in thickness is shown to be useful for the in vivo assessment of the regional elasticity of the arterial wall. Although the accuracy of the measurement of the change in thickness is found to be within 1 μm, it is affected by the interference of ultrasonic pulses. In this study, we simulate the propagation of ultrasonic pulses transmitted and received by a linear probe. In the simulation experiments, the ultrasonic pulses generated by a computer are reflected by a tube, which has a small change in wall thickness of 10 μm. The optimum focal position of the ultrasonic beam is determined by evaluating the root-mean-square (rms) error in the measured change in thickness.

  14. Integrated ultrasonic and petrographical characterization of carbonate building materials

    NASA Astrophysics Data System (ADS)

    Ligas, Paola; Fais, Silvana; Cuccuru, Francesco

    2014-05-01

    This paper presents the application of non-destructive ultrasonic techniques in evaluating the conservation state and quality of monumental carbonate building materials. Ultrasonic methods are very effective in detecting the elastic characteristics of the materials and thus their mechanical behaviour. They are non-destructive and effective both for site and laboratory tests, though it should be pointed out that ultrasonic data interpretation is extremely complex, since elastic wave velocity heavily depends on moisture, heterogeneity, porosity and other physical properties of the materials. In our study, considering both the nature of the building materials and the constructive types of the investigated monuments, the ultrasonic investigation was carried out in low frequency ultrasonic range (24 kHz - 54 kHz) with the aim of detecting damages and degradation zones and assessing the alterability of the investigated stones by studying the propagation of the longitudinal ultrasonic pulses. In fact alterations in the materials generally cause a decrease in longitudinal pulse velocity values. Therefore starting from longitudinal velocity values the elasto-mechanical behaviour of the stone materials can be deduced. To this aim empirical and effective relations between longitudinal velocity and mechanical properties of the rocks can be used, by transferring the fundamental concepts of the studies of reservoir rocks in the framework of hydrocarbon research to the diagnostic process on stone materials. The ultrasonic measurements were performed both in laboratory and in situ using the Portable Ultrasonic Non-Destructive Digital Indicating Tester (PUNDIT) by C.N.S. Electronics LTD. A number of experimental sessions were carried out choosing different modalities of data acquisition. On the basis of the results of the laboratory measurements, an in situ ultrasonic survey on significant monuments, have been carried out. The ultrasonic measurements were integrated by a

  15. Analysis of ultrasonic frequency response of surface attached fiber Bragg grating.

    PubMed

    Li, Zhuoxuan; Pei, Li; Dong, Bo; Ma, Cheng; Wang, Anbo

    2012-07-10

    In recent years, fiber Bragg grating (FBG), for the well-known advantages over other fiber optic sensors, has attracted more attention in ultrasonic inspection for structure health monitoring (SHM). Spectrum shift of FBG to ultrasonic wave is caused by the refractive index profile changing along the FBG, which can be attributed to nonuniform perturbation caused by strain-optic and geometric effects of ultrasonic wave. Response of FBG to the above two effects was analyzed firstly by the V-I transmission matrix model, showing high computing efficiency. Based on this model, spectra response of FBG under changing ultrasonic frequencies was simulated and discussed. In experiment, the system was able to detect a wideband ultrasonic wave ranging from 15 to 1380 kHz. These results would provide a guideline for an FBG-based acoustic detection system design in a specific ultrasonic frequency. PMID:22781246

  16. Ultrasonic-Assisted Synthesis of Graphite-Reinforced Al Matrix Nanocomposites

    NASA Astrophysics Data System (ADS)

    Christy Roshini, P.; Nagasivamuni, B.; Raj, Baldev; Ravi, K. R.

    2015-06-01

    A novel approach to produce Al-2 vol.% graphite nanocomposites using micron-sized graphite particles has been reported using conventional stir casting technique combined with ultrasonic treatment. Microstructural observations indicate that the visible agglomerations and porosities are significantly reduced after ultrasonic treatment. Transmission electron microscopy studies of ultrasonic-treated composites reveal that the size of the graphite particles is reduced substantially and its morphology is transformed into flake type structures. The width of the graphite flakes is reduced markedly with the increase in ultrasonic processing time and it is found to be in the range of 100-120 nm with an aspect ratio of 8.83 after 5 min of ultrasonication. Added to that, considerable improvement in the hardness values are noted for ultrasonic-treated Al-2 vol.% graphite composites when compared to conventional untreated composites. The mechanism behind the significant reduction in graphite particle size and porosity, uniform distribution of graphite particles and hardness increments are discussed.

  17. Ultrasonic communication in frogs.

    PubMed

    Feng, Albert S; Narins, Peter M; Xu, Chun-He; Lin, Wen-Yu; Yu, Zu-Lin; Qiu, Qiang; Xu, Zhi-Min; Shen, Jun-Xian

    2006-03-16

    Among vertebrates, only microchiropteran bats, cetaceans and some rodents are known to produce and detect ultrasounds (frequencies greater than 20 kHz) for the purpose of communication and/or echolocation, suggesting that this capacity might be restricted to mammals. Amphibians, reptiles and most birds generally have limited hearing capacity, with the ability to detect and produce sounds below approximately 12 kHz. Here we report evidence of ultrasonic communication in an amphibian, the concave-eared torrent frog (Amolops tormotus) from Huangshan Hot Springs, China. Males of A. tormotus produce diverse bird-like melodic calls with pronounced frequency modulations that often contain spectral energy in the ultrasonic range. To determine whether A. tormotus communicates using ultrasound to avoid masking by the wideband background noise of local fast-flowing streams, or whether the ultrasound is simply a by-product of the sound-production mechanism, we conducted acoustic playback experiments in the frogs' natural habitat. We found that the audible as well as the ultrasonic components of an A. tormotus call can evoke male vocal responses. Electrophysiological recordings from the auditory midbrain confirmed the ultrasonic hearing capacity of these frogs and that of a sympatric species facing similar environmental constraints. This extraordinary upward extension into the ultrasonic range of both the harmonic content of the advertisement calls and the frog's hearing sensitivity is likely to have co-evolved in response to the intense, predominantly low-frequency ambient noise from local streams. Because amphibians are a distinct evolutionary lineage from microchiropterans and cetaceans (which have evolved ultrasonic hearing to minimize congestion in the frequency bands used for sound communication and to increase hunting efficacy in darkness), ultrasonic perception in these animals represents a new example of independent evolution. PMID:16541072

  18. Efficient generation of 480 fs electrical pulses on transmission lines by photoconductive switching in metalorganic chemical vapor deposited CdTe

    NASA Astrophysics Data System (ADS)

    Nuss, Martin C.; Kisker, D. W.; Smith, P. R.; Harvey, T. E.

    1989-01-01

    Electrical pulses of only 480 fs duration have been generated by photoconductive switching in CdTe grown by ultraviolet-enhanced metalorganic chemical vapor deposition (MOCVD). In addition to the extremely fast switching times, MOCVD CdTe also exhibits a high mobility of 180 sq cm/V s and can be grown on almost any substrate, making it ideal for integration into existing circuits and devices.

  19. Ultrasonic characterization of materials hardness

    PubMed

    Badidi Bouda A; Benchaala; Alem

    2000-03-01

    In this paper, an experimental technique has been developed to measure velocities and attenuation of ultrasonic waves through a steel with a variable hardness. A correlation between ultrasonic measurements and steel hardness was investigated. PMID:10829663

  20. Simultaneous triple-modality imaging of diffuse reflectance, optoacoustic pressure and ultrasonic scattering using an acoustic-resolution photoacoustic microscope: feasibility study

    NASA Astrophysics Data System (ADS)

    Subochev, Pavel; Fiks, Ilya; Frenz, Martin; Turchin, llya

    2016-02-01

    The letter discusses the opportunity for cost-effective use of conventional optoacoustic hardware to realize additional imaging modalities such as ultrasonic microscopy and diffuse optical reflectometry within the same laser pulse. Optoacoustic methods for deep biomedical visualization are based on pulsed laser illumination of the internal tissue layers with scattered photons, however some of the back-scattered photons can be absorbed by the optoacoustic detector. Thermoelastic extension of the detector’s surface provides a probing pulse for an ultrasonic modality while the measurement of the amplitude of the probing ultrasonic pulse allows estimation of the diffuse reflectance from the object under investigation.

  1. Ultrasonics in Dentistry

    NASA Astrophysics Data System (ADS)

    Walmsley, A. D.

    Ultrasonic instruments have been used in dentistry since the 1950's. Initially they were used to cut teeth but very quickly they became established as an ultrasonic scaler which was used to remove deposits from the hard tissues of the tooth. This enabled the soft tissues around the tooth to return to health. The ultrasonic vibrations are generated in a thin metal probe and it is the working tip that is the active component of the instrument. Scanning laser vibrometry has shown that there is much variability in their movement which is related to the shape and cross sectional shape of the probe. The working instrument will also generate cavitation and microstreaming in the associated cooling water. This can be mapped out along the length of the instrument indicating which are the active areas. Ultrasonics has also found use for cleaning often inaccessible or different surfaces including root canal treatment and dental titanium implants. The use of ultrasonics to cut bone during different surgical techniques shows considerable promise. More research is indicated to determine how to maximize the efficiency of such instruments so that they are more clinically effective.

  2. Application of low intensity ultrasonics to cheese manufacturing processes.

    PubMed

    Benedito, J; Carcel, J A; Gonzalez, R; Mulet, A

    2002-05-01

    Ultrasound has been used to non-destructively assess the quality of many foods such as meat, fish, vegetables and dairy products. This paper addresses the applications of low intensity ultrasonics in the cheese manufacturing processes and highlights the areas where ultrasonics could be successfully implemented in the future. The decrease of ultrasonic attenuation during the renneting process can be used to determine the optimum cut time for cheese making. The ultrasonic velocity increases during maturation for those types of cheese that become harder during this manufacturing stage, thus being an indicator of the maturity degree. Moreover, ultrasonic measurements could be linked to sensory parameters. From the ultrasonic velocity measurements at two different temperatures, it is possible to assess cheese composition, thus allowing an improvement in the quality and uniformity of cheese commercialization. In addition, in pulse-echo mode it is possible to detect cracked pieces due to abnormal fermentations and also to assess the distance of the crack from the surface. PMID:12159930

  3. Cluster-enhanced sparse approximation of overlapping ultrasonic echoes.

    PubMed

    Mor, Etai; Aladjem, Mayer; Azoulay, Amnon

    2015-02-01

    Ultrasonic pulse-echo methods have been used extensively in non-destructive testing of layered structures. In acoustic measurements on thin layers, the resulting echoes from two successive interfaces overlap in time, making it difficult to assess the individual echo parameters. Over the last decade sparse approximation methods have been extensively used to address this issue. These methods employ a large dictionary of elementary functions (atoms) and attempt to select the smallest subset of atoms (sparsest approximation) that represent the ultrasonic signal accurately. In this paper we propose the cluster-enhanced sparse approximation (CESA) method for estimating overlapping ultrasonic echoes. CESA is specifically adapted to deal with a large number of signals acquired during an ultrasonic scan. It incorporates two principal algorithms. The first is a clustering algorithm, which divides a set of signals comprising an ultrasonic scan into groups of signals that can be approximated by the same set of atoms. The second is a two-stage iterative algorithm, which alternates between update of the atoms associated with each cluster, and re-clustering of the signals according to the updated atoms. Because CESA operates on clusters of signals, it achieves improved results in terms of approximation error and computation time compared with conventional sparse methods, which operate on each signal separately. The superior ability of CESA to approximate highly overlapping ultrasonic echoes is demonstrated through simulation and experiments on adhesively bonded structures. PMID:25643086

  4. Pulsed eddy current testing

    NASA Astrophysics Data System (ADS)

    Workman, G. L.

    1980-10-01

    Since a large number of the procedures used for inspecting the external tank are concerned with determining flaws in welds, there is a need to develop an inspection technique, which can be automated, to determine flaws in welds and structures with complex geometries. Techniques whereby an eddy current is generated in a metallic material and the changes in the circuit parameters due to material differences are observed, were chosen as one possible approach. Pulsed eddy current and its relationship to multifrequency techniques is discussed as well as some preliminary results obtained from observing pulsed waveforms with apparatus and algorithms currently in use for ultrasonic testing of welds. It can be shown the pulsed eddy current techniques can provide similar results, can eliminate some of the noncritical parameters affecting the eddy current signals, and can facilitate in the detection of critical parameter such as flaws, subsurface voids, and corrosion.

  5. Ultrasonic dip seal maintenance system

    DOEpatents

    Poindexter, Allan M.; Ricks, Herbert E.

    1978-01-01

    A system for removing impurities from the surfaces of liquid dip seals and or wetting the metal surfaces of liquid dip seals in nuclear components. The system comprises an ultrasonic transducer that transmits ultrasonic vibrations along an ultrasonic probe to the metal and liquid surfaces of the dip seal thereby loosening and removing those impurities.

  6. Artificial Intelligence Assists Ultrasonic Inspection

    NASA Technical Reports Server (NTRS)

    Schaefer, Lloyd A.; Willenberg, James D.

    1992-01-01

    Subtle indications of flaws extracted from ultrasonic waveforms. Ultrasonic-inspection system uses artificial intelligence to help in identification of hidden flaws in electron-beam-welded castings. System involves application of flaw-classification logic to analysis of ultrasonic waveforms.

  7. Acousto-ultrasonics

    NASA Technical Reports Server (NTRS)

    Vary, Alex

    1990-01-01

    The theoretical development, methodology, and potential applications of acousto-ultrasonic nondestructive testing are set forth in an overview to assess the effectiveness of the technique. Stochastic wave propagation is utilized to isolate and describe defects in fiber-reinforced composites, particularly emphasizing the integrated effects of diffuse populations of subcritical flaws. The generation and nature of acousto-ultrasonic signals are described in detail, and stress-wave factor analysis of the signals is discussed. Applications of acousto-ultrasonics are listed including the prediction of failure sites, assessing fatique and impact damage, calculating ultimate tensile strength, and determining interlaminar bond strength. The method can identify subtle but important variations in fiber-reinforced composites, and development of the related instrumentation technology is emphasized.

  8. Ultrasonic/Sonic Jackhammer

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph (Inventor); Sherrit, Stewart (Inventor); Herz, Jack L. (Inventor)

    2014-01-01

    The invention provides a novel jackhammer that utilizes ultrasonic and/or sonic vibrations as source of power. It is easy to operate and does not require extensive training, requiring substantially less physical capabilities from the user and thereby increasing the pool of potential operators. An important safety benefit is that it does not fracture resilient or compliant materials such as cable channels and conduits, tubing, plumbing, cabling and other embedded fixtures that may be encountered along the impact path. While the ultrasonic/sonic jackhammer of the invention is able to cut concrete and asphalt, it generates little back-propagated shocks or vibrations onto the mounting fixture, and can be operated from an automatic platform or robotic system. PNEUMATICS; ULTRASONICS; IMPACTORS; DRILLING; HAMMERS BRITTLE MATERIALS; DRILL BITS; PROTOTYPES; VIBRATION

  9. Ultrasonic Stir Welding

    NASA Technical Reports Server (NTRS)

    Nabors, Sammy

    2015-01-01

    NASA Marshall Space Flight Center (MSFC) developed Ultrasonic Stir Welding (USW) to join large pieces of very high-strength metals such as titanium and Inconel. USW, a solid-state weld process, improves current thermal stir welding processes by adding high-power ultrasonic (HPU) energy at 20 kHz frequency. The addition of ultrasonic energy significantly reduces axial, frictional, and shear forces; increases travel rates; and reduces wear on the stir rod, which results in extended stir rod life. The USW process decouples the heating, stirring, and forging elements found in the friction stir welding process allowing for independent control of each process element and, ultimately, greater process control and repeatability. Because of the independent control of USW process elements, closed-loop temperature control can be integrated into the system so that a constant weld nugget temperature can be maintained during welding.

  10. Ultrasonic nondestructive materials characterization

    NASA Technical Reports Server (NTRS)

    Green, R. E., Jr.

    1986-01-01

    A brief review of ultrasonic wave propagation in solid materials is presented with consideration of the altered behavior in anisotropic and nonlinear elastic materials in comparison with isotropic and linear elastic materials. Some experimental results are described in which ultrasonic velocity and attenuation measurements give insight into materials microstructure and associated mechanical properties. Recent developments with laser beam non-contact generation and detection of ultrasound are presented. The results of several years of experimental measurements using high-power ultrasound are discussed, which provide substantial evidence of the inability of presently accepted theories to fully explain the interaction of ultrasound with solid materials. Finally, a special synchrotron X-ray topographic system is described which affords the possibility of observing direct interaction of ultrasonic waves with the microstructural features of real crystalline solid materials for the first time.

  11. Ultrasonic Leak Detection System

    NASA Technical Reports Server (NTRS)

    Youngquist, Robert C. (Inventor); Moerk, J. Steven (Inventor)

    1998-01-01

    A system for detecting ultrasonic vibrations. such as those generated by a small leak in a pressurized container. vessel. pipe. or the like. comprises an ultrasonic transducer assembly and a processing circuit for converting transducer signals into an audio frequency range signal. The audio frequency range signal can be used to drive a pair of headphones worn by an operator. A diode rectifier based mixing circuit provides a simple, inexpensive way to mix the transducer signal with a square wave signal generated by an oscillator, and thereby generate the audio frequency signal. The sensitivity of the system is greatly increased through proper selection and matching of the system components. and the use of noise rejection filters and elements. In addition, a parabolic collecting horn is preferably employed which is mounted on the transducer assembly housing. The collecting horn increases sensitivity of the system by amplifying the received signals. and provides directionality which facilitates easier location of an ultrasonic vibration source.

  12. Ultrasonic Processing of Materials

    NASA Astrophysics Data System (ADS)

    Han, Qingyou

    2015-08-01

    Irradiation of high-energy ultrasonic vibration in metals and alloys generates oscillating strain and stress fields in solids, and introduces nonlinear effects such as cavitation, acoustic streaming, and radiation pressure in molten materials. These nonlinear effects can be utilized to assist conventional material processing processes. This article describes recent research at Oak Ridge National Labs and Purdue University on using high-intensity ultrasonic vibrations for degassing molten aluminum, processing particulate-reinforced metal matrix composites, refining metals and alloys during solidification process and welding, and producing bulk nanostructures in solid metals and alloys. Research results suggest that high-intensity ultrasonic vibration is capable of degassing and dispersing small particles in molten alloys, reducing grain size during alloy solidification, and inducing nanostructures in solid metals.

  13. Directivity measurements in aluminum using a laser ultrasonics system

    NASA Astrophysics Data System (ADS)

    Sakamoto, J. M. S.; Tittmann, B. R.; Baba, A.; Pacheco, G. M.

    2011-01-01

    A laser ultrasonics system was setup to measure the directivity (angular dependence pattern) of the amplitude of ultrasonic waves generated in aluminum samples. A pulsed Nd:YAG laser operating at 1064 nm optical wavelength, with typical pulse width (FWHM) of 8 ns, and energy per pulse of 450 mJ, was used to generate the ultrasound waves in the samples. The laser detection system was a Mach-Zehnder interferometer with typical noise-limited resolution of 0.25 nm (rms), frequency range from 50 kHz to 20 MHz, and measurement range from -75 nm/V to +75 nm/V. Two different optical spot sizes of the Nd:YAG laser were used to generate waves in the ablation regime: one was focused and the other was unfocused. Using the obtained data, the directivity graphics were drawn and compared with the theoretical curves, showing a good agreement. The experiments showed the directivity as a function of the optical spot size. For a point ultrasonic source (or focused optical spot), the directivity shows that the longitudinal waves present considerable amplitude in all directions. For a larger ultrasonic source (or an unfocused optical spot) the directivity shows that the longitudinal waves are generated with the higher amplitudes inside angles around ±10°.

  14. Experimental techniques in ultrasonics for NDE and material characterization

    NASA Astrophysics Data System (ADS)

    Tittmann, B. R.

    A development status evaluation is presented for ultrasonics NDE characterization of aerospace alloys and composites in such application as the Space Shuttle, Space Station Freedom, and hypersonic aircraft. The use of such NDE techniques extends to composite-cure monitoring, postmanufacturing quality assurance, and in-space service inspection of such materials as graphite/epoxy, Ti alloys, and Al honeycomb. Attention is here given to the spectroscopy of elastically scattered wave pulses from flaws, the acoustical imaging of flaws in honeycomb structures, and laser-based ultrasonics for the noncontact inspection of composite structures.

  15. Ultrasonic verification of microstructural changes due to heat treatment

    NASA Technical Reports Server (NTRS)

    Generazio, E. R.

    1986-01-01

    Ultrasonic attenuation was measured for polycrystalline samples of nickel and copper with various grain-size distributions produced by heat treatment. Attenuation as a function of frequency was determined for a sample having a known mean grain diameter. Once this function was determined, it could be scaled to determine the mean grain size of other samples of the same material with different mean grain diameters. These results were obtained by using broadband pulse-echo ultrasound in the 25 to 100 MHz frequency range. The results suggest an ultrasonic, nondestructive approach for verifying heat treatment of metals.

  16. Ultrasonic/Sonic Jackhammer

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph; Sherrit, Stewart; Herz, Jack

    2005-01-01

    An ultrasonic/sonic jackhammer (USJ) is the latest in a series of related devices. Each of these devices cuts into a brittle material by means of hammering and chiseling actions of a tool bit excited with a combination of ultrasonic and sonic vibrations. A small-scale prototype of the USJ has been demonstrated. A fully developed, full-scale version of the USJ would be used for cutting through concrete, rocks, hard asphalt, and other materials to which conventional pneumatic jackhammers are applied, but the USJ would offer several advantages over conventional pneumatic jackhammers.

  17. Ultrasonic Processing of Materials

    SciTech Connect

    Meek, Thomas T.; Han, Qingyou; Jian, Xiaogang; Xu, Hanbing

    2005-06-30

    The purpose of this project was to determine the impact of a new breakthrough technology, ultrasonic processing, on various industries, including steel, aluminum, metal casting, and forging. The specific goals of the project were to evaluate core principles and establish quantitative bases for the ultrasonc processing of materials, and to demonstrate key applications in the areas of grain refinement of alloys during solidification and degassing of alloy melts. This study focussed on two classes of materials - aluminum alloys and steels - and demonstrated the application of ultrasonic processing during ingot casting.

  18. Ultrasonic shear wave couplant

    DOEpatents

    Kupperman, D.S.; Lanham, R.N.

    1984-04-11

    Ultrasonically testing of an article at high temperatures is accomplished by the use of a compact layer of a dry ceramic powder as a couplant in a method which involves providing an ultrasonic transducer as a probe capable of transmitting shear waves, coupling the probe to the article through a thin compact layer of a dry ceramic powder, propagating a shear wave from the probe through the ceramic powder and into the article to develop echo signals, and analyzing the echo signals to determine at least one physical characteristic of the article.

  19. Ultrasonic shear wave couplant

    DOEpatents

    Kupperman, David S.; Lanham, Ronald N.

    1985-01-01

    Ultrasonically testing of an article at high temperatures is accomplished by the use of a compact layer of a dry ceramic powder as a couplant in a method which involves providing an ultrasonic transducer as a probe capable of transmitting shear waves, coupling the probe to the article through a thin compact layer of a dry ceramic powder, propagating a shear wave from the probe through the ceramic powder and into the article to develop echo signals, and analyzing the echo signals to determine at least one physical characteristic of the article.

  20. Ultrasonic wave techniques and characterization of filled elastomers and biodegradable polymers

    NASA Astrophysics Data System (ADS)

    Wu, Hsueh-Chang

    Ultrasonic wave technique is an excellent method for non-destructive testing and for the monitoring of polymer curing, fatigue damage and polymer transition. It is also a potentially effective tool to be applied in the characterization of high frequency viscoelastic properties of polymers. This research represents the effort to improve and further develop ultrasonic wave techniques and extend its applications to new material evaluation areas. The work is presented as followings: In chapter 1, the fundamental wave propagation theories and characterization of the viscoelastic properties of materials by acoustic parameters were briefly reviewed. In chapter 2, the effects of carbon black filler on the elastomers were studied by the longitudinal wave pulse-echo technique. It is found that the enhanced pulse-echo technique is able to characterize the effects of polymer base, filler loading level, type as well as temperature, on the acoustic properties of filled elastomers. In chapter 3, the application of longitudinal wave pulse-echo technique was extended to the monitoring of the degradation process of biodegradable polymers: poly (glycolic acid)(PGA), poly (lactic acid) (PLA) and their copolymer-poly(d,l-lactide-co-glycolide) (PDLLG). It shows that the pulse-echo technique is able to differentiate the effects of polymer structure and preparation method on the degradation behavior of biopolymers. In chapter 4, the Young's modulus, shear modulus, bulk modulus and Poisson ratio of carbon black filled elastomers were determined by the longitudinal wave pulse-echo method and the shear wave through-transmission method. The effects of polymer base, filler loading and dispersion on the elastomers were also studied by the calculated elastic constants. In chapter 5, the effects of carbon black filler on the elastomers were studied by an innovative calibrated longitudinal and shear wave surface impedance technique. The results show that the effects of polymer base, filler loading

  1. ULTRASOUND PULSE-ECHO IMAGING USING THE SPLIT-STEP FOURIER PROPAGATOR

    SciTech Connect

    HUANG, LIANJIE; QUAN, YOULI

    2007-01-31

    Ultrasonic reflection imaging has the potential to produce higher image resolution than transmission tomography, but imaging resolution and quality still need to be further improved for early cancer detection and diagnosis. We present an ultrasound reflection image reconstruction method using the split-step Fourier propagator. It is based on recursive inward continuation of ultrasonic wavefields in the frequency-space and frequency-wavenumber domains. The inward continuation within each extrapolation interval consists of two steps. In the first step, a phase-shift term is applied to the data in the frequency-wavenumber domain for propagation in a reference medium. The second step consists of applying another phase-shift term to data in the frequency-space domain to approximately compensate for ultrasonic scattering effects of heterogeneities within the breast. We use synthetic ultrasound pulse-echo data recorded around a ring for heterogeneous, computer-generated numerical breast phantoms to study the imaging capability of the method. The phantoms are derived from an experimental breast phantom and a sound-speed tomography image of an in-vivo ultrasound breast data collected usi ng a ring array. The heterogeneous sound-speed models used for pulse-echo imaging are obtained using a computationally efficient, first-arrival-time (time-of-flight) transmission tomography method. Our studies demonstrate that reflection image reconstruction using the split-step Fourier propagator with heterogeneous sound-speed models significantly improves image quality and resolution. We also numerically verify the spatial sampling criterion of wavefields for a ring transducer array.

  2. Exploring the use of Low-intensity Ultrasonics as a Tool for Assessing the Salt Content in Pork Meat Products

    NASA Astrophysics Data System (ADS)

    García-Pérez, J. V.; de Prados, M.; Martínez-Escrivá, G.; González, R.; Mulet, A.; Benedito, J.

    Meat industry demands non-destructive techniques for the control of the salting process to achieve a homogeneous final salt content in salted meat products. The feasibility of using low-intensity ultrasound for characterizing the salting process of pork meat products was evaluated. The ultrasonic velocity (V) and time of flight (TF) were measured by through-transmission and pulse-echo methods, respectively, in salted meat products. Salting involved an increase of the V in meat muscles and a decrease of the time of flight in whole hams. Measuring the V before and after salting, the salt content could be estimated. Moreover, online monitoring of the salting process by computing the TF could be considered a reliable tool for quality control purposes.

  3. Ultrasonic comb transducer for smart materials

    NASA Astrophysics Data System (ADS)

    Rose, J. L.

    1998-04-01

    Installation of a small multi-element comb type ultrasonic transducer is proposed as a component of a smart structure. It can be used in either an active or passive mode in carrying out ultrasonic bulk or guided wave nondestructive evaluation. Theoretical methods are developed and experimental results are presented for guided wave generation and mode control with this very efficient and versatile novel comb type ultrasonic transducer. Excitation and probe design is crucial in mode selection. The comb transducer generates waves that are influenced by such parameters as number of elements, spacing between elements, dimension, pulsing sequence, and pressure distribution. The excited elastic field depends on the excitation frequency, plate thickness, and elastic properties. Techniques are studied to optimize the applied loading and the comb transducer design parameters so that only modes that are most sensitive to particular material characteristics can be generated. Complete understanding of the comb transducer parameters and their impact on the elastic field allows us to efficiently generate higher order modes as well as low phase velocity modes which are valuable in composite material characterization. Sample experiments are presented for various plate and tube like structures.

  4. High energy, low frequency, ultrasonic transducer

    DOEpatents

    Brown, Albert E.

    2000-01-01

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

  5. ECG Gated Ultrasonic Small Animal Imaging.

    PubMed

    Liu, Jian-Hung; Jeng, Geng-Shi; Wu, Tung-Ke; Li, Pai-Chi

    2005-01-01

    Echocardiography is a routine clinical procedure to diagnose cardiac functions. The organic structure of the mouse is similar to that of human so that murine echocardiography has potentially become an effective tool for the assessment of human cardiovascular disease. However, clinical ultrasonic imaging systems are not suitable for murine cardiac imaging due to its limited spatial and temporal resolution. Thus, high frequency ultrasonic imaging (≥ 20 MHz) is necessary in order to provide spatial resolution at the order of 100 μm. Furthermore, due to the lack of transducer arrays at such a high frequency, single-element transducer with mechanical scanning is typically used. Thus the frame rate is insufficient for imaging the quick motion of the mouse. In this paper, a high frequency ultrasonic imaging system with electrocardiography gating is built in order to provide both high spatial resolution and high temporal effecting resolution. The system utilizes the R-wave trigger signal from murine electrocardiography. Image data are acquired in either the block scanning mode or the line scanning mode. In block scanning, murine cardiac images in systole and diastole can be retrospectively reconstructed with a short data acquisition time. In line scanning, on the other hand, images during the entire cardiac cycle can be obtained. It is demonstrated that the effective frame rate can be up to 2 kHz, which is only limited by the pulse repetition rate of the system. PMID:17282556

  6. Nondestructive Ultrasonic Inspection of Friction Stir Welds

    NASA Astrophysics Data System (ADS)

    Tabatabaeipour, M.; Hettler, J.; Delrue, S.; Van Den Abeele, K.

    Friction Stir Welding (FSW) is a relatively new solid-state welding procedure developed at The Welding Institute (TWI-UK) and the technique is widely employed for welding aluminum alloys in various applications. In order to examine the quality of the welds and to detect a variety of welding flaws such as wormholes and root-flaws, it is required to develop a methodical inspection technique that can be used for the identification and localization of such defects. The most prevalent and risky defect in this type of welding is the barely visible root flaw with a length varying from 100-700 μm. Due to the extreme characteristics of the flaw, off-the-shelf ultrasonic weld inspection methods are not always able to readily detect this type of minute defect feature. Here, we propose a novel approach to characterize root flaws using an oblique incident ultrasonic C-scan backscattering analysis. The implementation consists of an immersion ultrasonic testing method in pulse echo (i.e. backscatter) mode with a 3.5 MHz transducer, and makes use of an empirical procedure to engender of a shear wave dominated excitation at the root surface, and to properly gate the received signal for root flaw examination. By scanning the surface above the welded component, a C-scan image displaying the backscatter response from the root surface of the nugget zone can be obtained which allows a simple interpretation of the root flaw status of the weld.

  7. A device for human ultrasonic echolocation

    PubMed Central

    Gaub, Benjamin M.; Rodgers, Chris C.; Li, Crystal; DeWeese, Michael R.; Harper, Nicol S.

    2015-01-01

    Objective We present a device that combines principles of ultrasonic echolocation and spatial hearing to provide human users with environmental cues that are 1) not otherwise available to the human auditory system and 2) richer in object, and spatial information than the more heavily processed sonar cues of other assistive devices. The device consists of a wearable headset with an ultrasonic emitter and stereo microphones with affixed artificial pinnae. The goal of this study is to describe the device and evaluate the utility of the echoic information it provides. Methods The echoes of ultrasonic pulses were recorded and time-stretched to lower their frequencies into the human auditory range, then played back to the user. We tested performance among naive and experienced sighted volunteers using a set of localization experiments in which the locations of echo-reflective surfaces were judged using these time stretched echoes. Results Naive subjects were able to make laterality and distance judgments, suggesting that the echoes provide innately useful information without prior training. Naive subjects were generally unable to make elevation judgments from recorded echoes. However trained subjects demonstrated an ability to judge elevation as well. Conclusion This suggests that the device can be used effectively to examine the environment and that the human auditory system can rapidly adapt to these artificial echolocation cues. Significance Interpreting and interacting with the external world constitutes a major challenge for persons who are blind or visually impaired. This device has the potential to aid blind people in interacting with their environment. PMID:25608301

  8. Ultrasonic Study of Dislocation Dynamics in Lithium -

    NASA Astrophysics Data System (ADS)

    Han, Myeong-Deok

    1987-09-01

    Experimental studies of dislocation dynamics in LiF single crystals, using ultrasonic techniques combined with dynamic loading, were performed to investigate the time evolution of the plastic deformation process under a short stress pulse at room temperature, and the temperature dependence of the dislocation damping mechanism in the temperature range 25 - 300(DEGREES)K. From the former, the time dependence of the ultrasonic attenuation was understood as resulting from dislocation multiplication followed by the evolution of mobile dislocations to immobile ones under large stress. From the latter, the temperature dependence of the ultrasonic attenuation was interpreted as due to the motion of the dislocation loops overcoming the periodic Peierls potential barrier in a manner analogous to the motion of a thermalized sine-Gordon chain under a small stress. The Peierls stress obtained from the experimental results by application of Seeger's relaxation model with exponential dislocation length distribution was 4.26MPa, which is consistent with the lowest stress for the linear relation between the dislocation velocity and stress observed by Flinn and Tinder.

  9. Precision Thickness Variation Mapping Via One-Transducer Ultrasonic High Resolution Profilometry for Sample With Irregular or Rough Surface

    NASA Technical Reports Server (NTRS)

    Roth, Don J. (Inventor)

    1996-01-01

    An apparatus and method for determination of sample thickness and surface depression utilizing ultrasonic pulses is discussed. The sample is held in a predetermined position by a support member having a reference surface. Ultrasonic pulses travel through a medium of known velocity propagation and reflect off the reference surface and a sample surface. Time of flight data of surface echoes are converted to distances between sample surfaces to obtain computer-generated thickness profiles and surface mappings.

  10. Precision Thickness Variation Mapping via One-Transducer Ultrasonic High Resolution Profilometry for Sample with Irregular or Rough Surface

    NASA Technical Reports Server (NTRS)

    Roth, Don J. (Inventor)

    1997-01-01

    An apparatus and method for determination of sample thickness and surface depression utilizing ultrasonic pulses. The sample is held in a predetermined position by a support member having a reference surface. Ultrasonic pulses travel through a medium of known velocity propagation and reflect off the reference surface and a sample surface. Time of flight data of surface echoes are converted to distances between sample surfaces to obtain computer-generated thickness profiles and surface mappings.

  11. Borehole data transmission apparatus

    DOEpatents

    Kotlyar, O.M.

    1993-03-23

    A borehole data transmission apparatus is described whereby a centrifugal pump impeller(s) is used to provide a turbine stage having substantial pressure characteristics in response to changing rotational speed of a shaft for the pressure pulsing of data from the borehole through the drilling mud to the surface of the earth.

  12. Borehole data transmission apparatus

    DOEpatents

    Kotlyar, Oleg M.

    1993-01-01

    A borehole data transmission apparatus whereby a centrifugal pump impeller(s) is used to provide a turbine stage having substantial pressure characteristics in response to changing rotational speed of a shaft for the pressure pulsing of data from the borehole through the drilling mud to the surface of the earth.

  13. Transmission Spectra and Generation of Terahertz Pulses in SiO2-GaSe, TiO2-GaSe, Ga2O3-GaSe, and GaSe:S Structures

    NASA Astrophysics Data System (ADS)

    Bereznaya, S. A.; Zarubin, A. N.; Korotchenko, Z. V.; Prudaev, I. A.; Red'kin, R. A.; Sarkisov, S. Yu.; Tolbanov, O. P.

    2015-12-01

    Thin amorphous SiO2, TiO2, and Ga2O3 films were deposited on the surface of GaSe crystals by thermal and magnetron sputtering. It was found that under different technological conditions, the SiO2 and TiO2 layers on the surface of GaSe crack, while the Ga2O3 compound forms perfect films. A comparison of the transmission spectra and generation efficiency of terahertz pulses was made for the SiO2-GaSe, TiO2-GaSe, and Ga2O3-GaSe structures and for the GaSe:S 0.9 wt % and GaSe:S 7 wt % crystals. It was found that an increase in the concentration of sulfur in the GaSe:S crystals results in a decrease in the efficiency of generation of terahertz radiation by optical rectification of femtosecond laser pulses. Among the films deposited on the surface of GaSe, the SiO2 film has the least impact on the efficiency of generation.

  14. Transmission electron microscopy study of amorphous Ge2Sb2Te5 films induced by an ultraviolet single-pulse laser

    NASA Astrophysics Data System (ADS)

    Zhao, J. J.; Liu, F. R.; Han, X. X.; Zhu, Z.; Lin, X.; Liu, F.; Sun, N. X.

    2014-08-01

    Crystallization behaviors of α-GST films with the thickness of 80 and 30 nm induced by an ultraviolet pulse laser were investigated by using TEM integrated with SAED. Firstly, crystalline phase morphologies were shown and analyzed. Both plate grains and spherical grains were found for 80 nm thick film, while only plate grains were found for 30 nm thick film. Then the relationship between the grain size and laser fluence for the 80 nm thick film was studied and the effects of film thickness on crystallization morphology were analyzed. Finally a crystallization process model based on the relationship of the crystallization starting temperature and heating temperature was constructed to elucidate how the solid-phase crystallization and melt-cooling crystallization occurred and developed. It also unified the crystallization starting temperature under static conditions and the crystallization starting temperature under laser inducing conditions.

  15. Coupling apparatus for ultrasonic medical diagnostic system

    NASA Technical Reports Server (NTRS)

    Frazer, R. E. (Inventor)

    1978-01-01

    An apparatus for the ultrasonic scanning of a breast or other tissue is reported that contains a cavity for receiving the breast, a vacuum for drawing the breast into intimate contact with the walls of the cavity, and transducers coupled through a fluid to the cavity to transmit sound waves through the breast. Each transducer lies at the end of a tapered chamber which has flexible walls and which is filled with fluid, so that the transducer can be moved in a raster pattern while the chamber walls flex accordingly, with sound transmission always occurring through the fluid.

  16. Ultrasonic characterization of solid liquid suspensions

    DOEpatents

    Panetta, Paul D.

    2010-06-22

    Using an ultrasonic field, properties of a solid liquid suspension such as through-transmission attenuation, backscattering, and diffuse field are measured. These properties are converted to quantities indicating the strength of different loss mechanisms (such as absorption, single scattering and multiple scattering) among particles in the suspension. Such separation of the loss mechanisms can allow for direct comparison of the attenuating effects of the mechanisms. These comparisons can also indicate a model most likely to accurately characterize the suspension and can aid in determination of properties such as particle size, concentration, and density of the suspension.

  17. Scanning ultrasonic probe

    DOEpatents

    Kupperman, David S.; Reimann, Karl J.

    1982-01-01

    The invention is an ultrasonic testing device for rapid and complete examination of the test specimen, and is particularly well suited for evaluation of tubular test geometries. A variety of defect categories may be detected and analyzed at one time and their positions accurately located in a single pass down the test specimen.

  18. Experiments with Ultrasonic Transducers.

    ERIC Educational Resources Information Center

    Greenslade, Thomas R., Jr.

    1994-01-01

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

  19. Broadband Ultrasonic Transducers

    NASA Technical Reports Server (NTRS)

    Heyser, R. C.

    1986-01-01

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

  20. Scanning ultrasonic probe

    DOEpatents

    Kupperman, D.S.; Reimann, K.J.

    1980-12-09

    The invention is an ultrasonic testing device for rapid and complete examination of the test specimen, and is particularly well suited for evaluation of tubular test geometries. A variety of defect categories may be detected and anlayzed at one time and their positions accurately located in a single pass down the test specimen.

  1. Ultrasonic Drilling and Coring

    NASA Technical Reports Server (NTRS)

    Bar-Cohen, Yoseph

    1998-01-01

    A novel drilling and coring device, driven by a combination, of sonic and ultrasonic vibration, was developed. The device is applicable to soft and hard objects using low axial load and potentially operational under extreme conditions. The device has numerous potential planetary applications. Significant potential for commercialization in construction, demining, drilling and medical technologies.

  2. Ultrasonic Transducer Analyzer

    NASA Technical Reports Server (NTRS)

    Grounds, M. K.

    1982-01-01

    Ultrasonic transducer-beam-intensity distributions are determined by analyzing echoes from a spherical ball. Computers control equipment and process data. Important beam characteristics, such as location of best beam focus and beam diameter at focus, can be determined quickly from extensive set of plots generated by apparatus.

  3. Modeling of multilayered piezoelectric transducers with ultrasonic welding application

    NASA Astrophysics Data System (ADS)

    Güney, Murat; Eskinat, Esref

    2007-04-01

    Mechanical components of sandwiched piezoelectric transducers are modeled using one-dimensional wave transmission and piezoelectric equations. Using the impedance method, resonance frequencies, stress and displacement distributions along the multilayered piezoelectric transducers of different dimensions and materials are obtained. The calculated resonance frequencies and the impedances are experimentally verified. For ultrasonic welding of plastics, the effect of the parts to be welded on the resonance frequency of the whole system is investigated regarding both material damping and piezoelectric losses. Using the methods developed, several piezoelectric transducers are analysed for different designs. The obtained results can be used to better understand the qualitative relations between the design variables of ultrasonic piezoelectric transducers.

  4. Plate Wave Resonance with Air-Coupled Ultrasonics

    NASA Astrophysics Data System (ADS)

    Bar, H. N.; Dayal, V.; Barnard, D.; Hsu, D. K.

    2010-02-01

    Air-coupled ultrasonic transducers can excite plate waves in metals and composites. The coincidence effect, i.e., the wave vector of plate wave coincides with projection of exciting airborne sound vector, leads to a resonance which strongly amplifies the sound transmission through the plate. The resonance depends on the angle of incidence and the frequency. In the present study, the incidence angle for maximum transmission (θmax) is measured in plates of steel, aluminum, carbon fiber reinforced composites and honeycomb sandwich panels. The variations of (θmax) with plate thickness are compared with theoretical values in steel, aluminum and quasi-isotropic carbon fiber composites. The enhanced transmission of air-coupled ultrasound at oblique incidence can substantially improve the probability of flaw detection in plates and especially in honeycomb structures. Experimental air-coupled ultrasonic scan of subtle flaws in CFRP laminates showed definite improvement of signal-to-noise ratio with oblique incidence at θmax.

  5. Pulse shaping system

    DOEpatents

    Skeldon, M.D.; Letzring, S.A.

    1999-03-23

    Temporally shaped electrical waveform generation provides electrical waveforms suitable for driving an electro-optic modulator (EOM) which produces temporally shaped optical laser pulses for inertial confinement fusion (ICF) research. The temporally shaped electrical waveform generation is carried out with aperture coupled transmission lines having an input transmission line and an aperture coupled output transmission line, along which input and output pulses propagate in opposite directions. The output electrical waveforms are shaped principally due to the selection of coupling aperture width, in a direction transverse to the lines, which varies along the length of the line. Specific electrical waveforms, which may be high voltage (up to kilovolt range), are produced and applied to the EOM to produce specifically shaped optical laser pulses. 8 figs.

  6. Pulse shaping system

    DOEpatents

    Skeldon, Mark D.; Letzring, Samuel A.

    1999-03-23

    Temporally shaped electrical waveform generation provides electrical waveforms suitable for driving an electro-optic modulator (EOM) which produces temporally shaped optical laser pulses for inertial confinement fusion (ICF) research. The temporally shaped electrical waveform generation is carried out with aperture coupled transmission lines having an input transmission line and an aperture coupled output transmission line, along which input and output pulses propagate in opposite directions. The output electrical waveforms are shaped principally due to the selection of coupling aperture width, in a direction transverse to the lines, which varies along the length of the line. Specific electrical waveforms, which may be high voltage (up to kilovolt range), are produced and applied to the EOM to produce specifically shaped optical laser pulses.

  7. Determination of inlet transmission and conversion efficiencies for in situ measurements of the nocturnal nitrogen oxides, NO3, N2O5 and NO2, via pulsed cavity ring-down spectroscopy.

    PubMed

    Fuchs, Hendrik; Dubé, William P; Ciciora, Steven J; Brown, Steven S

    2008-08-01

    Pulsed cavity ring-down spectroscopy is a highly sensitive method for direct absorption spectroscopy that has been applied to in situ detection of NO3, N2O5 and NO2 in the atmosphere from a variety of platforms, including ships, aircraft, and towers. In this paper, we report the development of schemes to significantly improve the accuracy of these measurements. This includes the following: (1) an overall improvement in the inlet transmission efficiencies (92 +/- 2% for NO3 and 97 +/- 1% for N2O5) achieved primarily through a reduction in the inlet residence time; and (2) the development of a calibration procedure that allows regular determination of these efficiencies in the field by addition of NO3 or N2O5 to the inlet from a portable source followed by conversion of NO3 to NO2. In addition, the dependence of the instrument's sensitivity and accuracy to a variety of conditions encountered in the field, including variations in relative humidity, aerosol loading, and VOC levels, was systematically investigated. The rate of degradation of N2O5 transmission efficiency on the inlet and filter system due to the accumulation of inorganic aerosol was determined, such that the frequency of filter changes required for accurate measurements could be defined. In the absence of aerosol, the presence of varying levels of relative humidity and reactive VOC were found to be unimportant factors in the instrument's performance. The 1 sigma accuracy of the NO3, N2O5, and NO2 measured with this instrument are -9/+12, -8/+11, +/- 6%, respectively, where the -/+ signs indicate that the actual value is low/high relative to the measurement. The largest contribution to the overall uncertainty is now due to the NO3 absorption cross section rather than the inlet transmission efficiency. PMID:18588318

  8. A sparse reconstruction algorithm for ultrasonic images in nondestructive testing.

    PubMed

    Guarneri, Giovanni Alfredo; Pipa, Daniel Rodrigues; Neves Junior, Flávio; de Arruda, Lúcia Valéria Ramos; Zibetti, Marcelo Victor Wüst

    2015-01-01

    Ultrasound imaging systems (UIS) are essential tools in nondestructive testing (NDT). In general, the quality of images depends on two factors: system hardware features and image reconstruction algorithms. This paper presents a new image reconstruction algorithm for ultrasonic NDT. The algorithm reconstructs images from A-scan signals acquired by an ultrasonic imaging system with a monostatic transducer in pulse-echo configuration. It is based on regularized least squares using a l1 regularization norm. The method is tested to reconstruct an image of a point-like reflector, using both simulated and real data. The resolution of reconstructed image is compared with four traditional ultrasonic imaging reconstruction algorithms: B-scan, SAFT, ω-k SAFT and regularized least squares (RLS). The method demonstrates significant resolution improvement when compared with B-scan-about 91% using real data. The proposed scheme also outperforms traditional algorithms in terms of signal-to-noise ratio (SNR). PMID:25905700

  9. Multimode-Guided-Wave Ultrasonic Scanning of Materials

    NASA Technical Reports Server (NTRS)

    Roth, Don

    2006-01-01

    Two documents discuss a method of characterizing advanced composite materials by use of multimode-guided ultrasonic waves. A transmitting transducer excites modulated (e.g., pulsed) ultrasonic waves at one location on a surface of a plate specimen. The waves interact with microstructure and flaws as they propagate through the specimen to a receiving transducer at a different location. The received signal is analyzed to determine the total (multimode) ultrasonic response of the specimen and utilize this response to evaluate microstructure and flaws. The analysis is performed by software that extracts parameters of signals in the time and frequency domains. Scanning is effected by using computer-controlled motorized translation stages to position the transducers at specified pairs of locations and repeating the measurement, data-acquisition, and data-analysis processes at the successive locations. One document presents results of a scan of a specimen containing a delamination.

  10. Simulation of transducer-couplant effects on broadband ultrasonic signals

    NASA Technical Reports Server (NTRS)

    Vary, A.

    1980-01-01

    The increasing use of broadband, pulse-echo ultrasonics in nondestructive evaluation of flaws and material properties has generated a need for improved understanding of the way signals are modified by coupled and bonded thin-layer interfaces associated with transducers. This understanding is most important when using frequency spectrum analyses for characterizing material properties. In this type of application, signals emanating from material specimens can be strongly influenced by couplant and bond-layers in the acoustic path. Computer synthesized waveforms were used to simulate a range of interface conditions encountered in ultrasonic transducer systems operating in the 20 to 80 MHz regime. The adverse effects of thin-layer multiple reflections associated with various acoustic impedance conditions are demonstrated. The information presented is relevant to ultrasonic transducer design, specimen preparation, and couplant selection.

  11. A Sparse Reconstruction Algorithm for Ultrasonic Images in Nondestructive Testing

    PubMed Central

    Guarneri, Giovanni Alfredo; Pipa, Daniel Rodrigues; Junior, Flávio Neves; de Arruda, Lúcia Valéria Ramos; Zibetti, Marcelo Victor Wüst

    2015-01-01

    Ultrasound imaging systems (UIS) are essential tools in nondestructive testing (NDT). In general, the quality of images depends on two factors: system hardware features and image reconstruction algorithms. This paper presents a new image reconstruction algorithm for ultrasonic NDT. The algorithm reconstructs images from A-scan signals acquired by an ultrasonic imaging system with a monostatic transducer in pulse-echo configuration. It is based on regularized least squares using a l1 regularization norm. The method is tested to reconstruct an image of a point-like reflector, using both simulated and real data. The resolution of reconstructed image is compared with four traditional ultrasonic imaging reconstruction algorithms: B-scan, SAFT, ω-k SAFT and regularized least squares (RLS). The method demonstrates significant resolution improvement when compared with B-scan—about 91% using real data. The proposed scheme also outperforms traditional algorithms in terms of signal-to-noise ratio (SNR). PMID:25905700

  12. Ultrasonic cleaning: Fundamental theory and application

    NASA Technical Reports Server (NTRS)

    Fuchs, F. John

    1995-01-01

    This presentation describes: the theory of ultrasonics, cavitation and implosion; the importance and application of ultrasonics in precision cleaning; explanations of ultrasonic cleaning equipment options and their application; process parameters for ultrasonic cleaning; and proper operation of ultrasonic cleaning equipment to achieve maximum results.

  13. Broadband high-frequency measurement of ultrasonic attenuation of tissues and liquids.

    PubMed

    Bauer-Marschallinger, Johannes; Berer, Thomas; Grun, Hubert; Roitner, Heinz; Reitinger, Bernhard; Burgholzer, Peter

    2012-12-01

    The ongoing expansion of the frequency range used for ultrasonic imaging requires increasing attention to the acoustic attenuation of biomaterials. This work presents a novel method for measuring the attenuation of tissue and liquids in vitro on the basis of single transmission measurements. Ultrasound was generated by short laser pulses directed onto a silicon wafer. In addition, unfocused piezoelectric transducers with a center frequency of 50 MHz were used to detect and emit ultrasound. The laser ultrasound method produces signals with a peak frequency of 30 MHz. In comparison to piezoelectric generation, pulse laser excitation provides approximately 4 times higher amplitudes and 20% larger bandwidth. By using two excitation methods in succession, the attenuation parameters of porcine fat samples with thicknesses in the range of 1.5 to 20 mm could be determined quantitatively within a total frequency range of 5 to 45 MHz. The setup for liquid measurements was tested on samples of human blood and olive oil. Our results are in good agreement with reports in literature. PMID:23221212

  14. Effect of Thermal Degradation on High Temperature Ultrasonic Transducer Performance in Small Modular Reactors

    NASA Astrophysics Data System (ADS)

    Bilgunde, Prathamesh N.; Bond, Leonard J.

    Prototype ultrasonic NDT transducers for use in immersion in coolants for small modular reactors have shown low signal to noise ratio. The reasons for the limitations in performance at high temperature are under investigation, and include changes in component properties. This current work seeks to quantify the issue of thermal expansion and degradation of the piezoelectric material in a transducer using a finite element method. The computational model represents an experimental set up for an ultrasonic transducer in a pulse-echo mode immersed in a liquid sodium coolant. Effect on transmitted and received ultrasonic signal due to elevated temperature (∼200oC) has been analysed.

  15. In-flight measurement of ice growth on an airfoil using an array of ultrasonic transducers

    NASA Technical Reports Server (NTRS)

    Hansman, R. John, Jr.; Kirby, Mark S.; Mcknight, Robert C.; Humes, Robert L.

    1988-01-01

    Results of preliminary tests to measure ice growth on an airfoil during flight icing conditions are presented. Ultrasonic pulse echo measurements of ice thickness are obtained from an array of eight ultrasonic transducers mounted flush with the leading edge of the airfoil. These thickness measurements are used to document the evolution of the ice shape during the encounter in the form of successive ice profiles. Results from 3 research flights are presented and discussed. The accuracy of the ultrasonic measurements is found to be within 0.5 mm of mechanical and stereo photograph measurements of the ice accretion.

  16. Ultrasonic texture characterization of aluminum, zirconium and titanium alloys

    SciTech Connect

    Anderson, A.J.

    1997-10-08

    This work attempts to show the feasibility of nondestructive characterization of non-ferrous alloys. Aluminum alloys have a small single crystal anisotropy which requires very precise ultrasonic velocity measurements for derivation of orientation distribution coefficients (ODCs); the precision in the ultrasonic velocity measurement required for aluminum alloys is much greater than is necessary for iron alloys or other alloys with a large single crystal anisotropy. To provide greater precision, some signal processing corrections need to be applied to account for the inherent, half-bandwidth offset in triggered pulses when using a zero-crossing technique for determining ultrasonic velocity. In addition, alloys with small single crystal anisotropy show a larger dependence on the single crystal elastic constants (SCECs) when predicting ODCs which require absolute velocity measurements. Attempts were made to independently determine these elastics constants in an effort to improve correlation between ultrasonically derived ODCs and diffraction derived ODCs. The greater precision required to accurately derive ODCs in aluminum alloys using ultrasonic nondestructive techniques is easily attainable. Ultrasonically derived ODCs show good correlation with derivations made by Bragg diffraction techniques, both neutron and X-ray. The best correlation was shown when relative velocity measurements could be used in the derivations of the ODCs. Calculation of ODCs in materials with hexagonal crystallites can also be done. Because of the crystallite symmetries, more information can be extracted using ultrasonic techniques, but at a cost of requiring more physical measurements. Some industries which use materials with hexagonal crystallites, e.g. zirconium alloys and titanium, have traditionally used texture parameters which provide some specialized measure of the texture. These texture parameters, called Kearns factors, can be directly related to ODCs.

  17. Non-contact feature detection using ultrasonic Lamb waves

    DOEpatents

    Sinha, Dipen N.

    2011-06-28

    Apparatus and method for non-contact ultrasonic detection of features on or within the walls of hollow pipes are described. An air-coupled, high-power ultrasonic transducer for generating guided waves in the pipe wall, and a high-sensitivity, air-coupled transducer for detecting these waves, are disposed at a distance apart and at chosen angle with respect to the surface of the pipe, either inside of or outside of the pipe. Measurements may be made in reflection or transmission modes depending on the relative position of the transducers and the pipe. Data are taken by sweeping the frequency of the incident ultrasonic waves, using a tracking narrow-band filter to reduce detected noise, and transforming the frequency domain data into the time domain using fast Fourier transformation, if required.

  18. Ultrasonic wave velocity measurement in small polymeric and cortical bone specimens

    NASA Technical Reports Server (NTRS)

    Kohles, S. S.; Bowers, J. R.; Vailas, A. C.; Vanderby, R. Jr

    1997-01-01

    A system was refined for the determination of the bulk ultrasonic wave propagation velocity in small cortical bone specimens. Longitudinal and shear wave propagations were measured using ceramic, piezoelectric 20 and 5 MHz transducers, respectively. Results of the pulse transmission technique were refined via the measurement of the system delay time. The precision and accuracy of the system were quantified using small specimens of polyoxymethylene, polystyrene-butadiene, and high-density polyethylene. These polymeric materials had known acoustic properties, similarity of propagation velocities to cortical bone, and minimal sample inhomogeneity. Dependence of longitudinal and transverse specimen dimensions upon propagation times was quantified. To confirm the consistency of longitudinal wave propagation in small cortical bone specimens (< 1.0 mm), cut-down specimens were prepared from a normal rat femur. Finally, cortical samples were prepared from each of ten normal rat femora, and Young's moduli (Eii), shear moduli (Gij), and Poisson ratios (Vij) were measured. For all specimens (bone, polyoxymethylene, polystyrene-butadiene, and high-density polyethylene), strong linear correlations (R2 > 0.997) were maintained between propagation time and distance throughout the size ranges down to less than 0.4 mm. Results for polyoxymethylene, polystyrene-butadiene, and high-density polyethylene were accurate to within 5 percent of reported literature values. Measurement repeatability (precision) improved with an increase in the wave transmission distance (propagating dimension). No statistically significant effect due to the transverse dimension was detected.

  19. Cheese maturity assessment using ultrasonics.

    PubMed

    Benedito, J; Carcel, J; Clemente, G; Mulet, A

    2000-02-01

    The relationship between Mahon cheese maturity and ultrasonic velocity was examined. Moisture and textural properties were used as maturity indicators. The ultrasonic velocity of the cheese varied between 1630 and 1740 m/s, increasing with the curing time mainly because of loss of water, which also produced an increase of the textural properties. Because of the nature of low-intensity ultrasonics, velocity was better related to those textural parameters that involved small displacements. Ultrasonic velocity decreased with increasing temperature because of the negative temperature coefficient of the ultrasonic velocity of fat and the melting of fat. These results highlight the potential use of ultrasonic velocity measurements to rapidly and nondestructively assess cheese maturity. PMID:10714857

  20. Photodistruptive laser nucleation of ultrasonic cavitation for biomedical applications

    NASA Astrophysics Data System (ADS)

    Miller, Doug L.; Spooner, Greg J.; Williams, Alun R.

    2001-07-01

    Pulses of high intensity laser light, when focused into transparent materials, may produce localized electron-ion plasmas through optical breakdown. By simultaneously incorporating the resulting volume of vaporized material within the focal volume of a high intensity ultrasound source, the photodisruption (1.05 micrometers wavelength) void served as a nucleation site for ultrasonic cavitation. Dilute suspensions of canine erythrocytes in phosphate buffered saline were exposed in a flow-through exposure chamber and the percentage of lysed cells was used as a measure of the biologically effective cavitation activity produced in the chamber. Brief (about 30 microsecond(s) ) acoustic emissions were detected from the photodisruption alone (indicating laser nucleation of bubbles), but the cell lysis produced was undetectable against the background. However, combined exposure greatly increased both the duration of the acoustic emissions (up to 1.5 ms) and the amount of cell lysis above an ultrasonic pressure amplitude threshold of about 4.3 MPa at 2.5 MHz. The amount of cell lysis (sometimes approaching 100%) increased with increasing ultrasonic intensity, laser pulse energy and laser PRF. Addition of 5% serum albumin enhanced the effect, apparently by stabilizing bubbles and nuclei. Photodisruptive laser nucleation of ultrasonic cavitation can provide controlled and synergistic enhancement of bioeffects.

  1. Comparison of ultrasonic image features with echodynamic curves for defect classification and characterization

    NASA Astrophysics Data System (ADS)

    Zhang, Jie; Wedge, Sam; Rogerson, Allan; Drinkwater, Bruce

    2015-03-01

    Ultrasonic array imaging and multi-probe pulse echo inspection are two common ultrasonic techniques used for defect detection, classification and characterization in non-destructive evaluation. Compared to multi-probe pulse echo inspection, ultrasonic array imaging offers some advantages such as higher resolution images and the requirement to obtain fewer measurements. However, it is also limited by a lack of industry-approved inspection procedures and standards. In this paper, several artificial planar and volumetric weld defects of different orientations and locations embedded in 60 mm thick welded ferritic test specimens were measured using both ultrasonic arrays and multiple single crystal probes. The resultant TFM images and echodynamic curves for each defect were compared and the results demonstrate the correlations between TFM image features and echodynamic curve characteristics. Combining the analysis of multi-probe pulse echo inspection data and ultrasonic array images offers better classification and characterization of defects. These findings benefit the further development of industrial ultrasonic array inspection procedures and encourage the uptake of TFM technology within industry.

  2. [Ultrasonic diagnosis of chest injuries].

    PubMed

    Tsurupa, D I; Deriabin, A I

    1982-03-01

    Ultrasonic diagnostic examinations were used in 365 patients with closed injuries (150), wounds (181) and consequences of traumas (34). The ultrasonic method allows to rapidly and exactly determine the presence and limits of the exudate, blood, coagulated hemothorax, residual cavity, thickness of the parietal and visceral layers of the pleura, the state of the pulmonary tissue (inflammation, blood inhibition, atelectasis). The ultrasonic method is simple, harmless and applicable under conditions of any surgical hospital. PMID:7080405

  3. [Development of ultrasonic power meter].

    PubMed

    Huang, Hongxin; Hu, Changming; Zheng, Yan; Xu, Honglei; Zhou, Wohua; Wu, Ziwen; Yu, Liudan; Hao, Jiandong; Luo, Yifan

    2014-07-01

    This article describes the design and development of an ultrasonic power meter which is consist of an electronic balance, a practice target, an acoustic enclosures and a blocking. The electronic balance mounted on the blocking is linked with the practice target by connecting rod. By adjusting the blocking makes the practice target suspended above ultrasound probe, and then the ultrasonic power can be measured. After initial tests, the ultrasonic power meter performanced with good stability and high precision. PMID:25330604

  4. Miniature implantable ultrasonic echosonometer

    NASA Technical Reports Server (NTRS)

    Kojima, G. K. (Inventor)

    1978-01-01

    A miniature echosonometer adapted for implantation in the interior of an animal for imaging the internal structure of a organ, tissue or vessel is presented. The echosonometer includes a receiver/transmitter circuit which is coupled to an ultrasonic transducer. Power is coupled to the echosonometer by electromagnetic induction through the animal's skin. Imaging signals from the echosonometer are electromagnetically transmitted through the animal's skin to an external readout apparatus.

  5. Ultrasonic Clothes Drying Technology

    ScienceCinema

    Patel, Viral; Momen, Ayyoub

    2016-05-12

    Oak Ridge National Laboratory researchers Ayyoub Momen and Viral Patel demonstrate a direct contact ultrasonic clothes dryer under development by ORNL in collaboration with General Electric (GE) Appliances. This novel approach uses high-frequency mechanical vibrations instead of heat to extract moisture as cold mist, dramatically reducing drying time and energy use. Funding for this project was competitively awarded by DOE?s Building Technologies Office in 2014.

  6. Ultrasonic differential measurement

    DOEpatents

    Rhodes, George W.; Migliori, Albert

    1995-01-01

    A method and apparatus for ultrasonic resonance testing of an object is shown and described. Acoustic vibrations are applied to an object at a plurality of frequencies. Measurements of the object's vibrational response are made simultaneously at different locations on said object. The input frequency is stepped by using small frequency changes over a predetermined range. There is a pause interval or ring delay which permits the object to reach a steady state resonance before a measurement is taken.

  7. Ultrasonic techniques for process monitoring and control.

    SciTech Connect

    Chien, H.-T.

    1999-03-24

    Ultrasonic techniques have been applied successfully to process monitoring and control for many industries, such as energy, medical, textile, oil, and material. It helps those industries in quality control, energy efficiency improving, waste reducing, and cost saving. This paper presents four ultrasonic systems, ultrasonic viscometer, on-loom, real-time ultrasonic imaging system, ultrasonic leak detection system, and ultrasonic solid concentration monitoring system, developed at Argonne National Laboratory in the past five years for various applications.

  8. Sharpening of ultrasonic scalers.

    PubMed

    Checchi, L; Pelliccioni, G A; D'Achille, C

    1991-08-01

    Instruments suitable for removing calculus, plaque and necrotic cementum, which hinder normal periodontal reattachment, are extremely important for successful therapy. The test was carried out in order to see if a standard scaler used for ultrasonic tartar removal maintains its physical features when sharpened. 6 scalers, compatible with piezo-electric generators, were tested and 2 diameters, A and B, weights and resonance frequencies were measured. Scalers no. 2, 3, 4, 5, were sharpened and was used as control. All measurements were taken again at the end of the test. Statistical analysis reveals significant variations, after sharpening, of A diameter (t = 4.14 greater than 3.55, p less than 0.01), B diameter (t = 5.34 greater than 3.355, p less than 0.01) and resonance frequency (t = 2.82 greater than 2.306, p less than 0.05); in contrast, there is no significant change of weights (t = 1.17 less than 2.306, p greater than 0.05). These results suggest that sharpening slightly modifies the physical features of ultrasonic tips, so that sharpening ultrasonic scalers, from a physical point of view, can be carried out, paying attention not to damage the water cooling system. PMID:1894743

  9. Ultrasonic Cutting of Foods

    NASA Astrophysics Data System (ADS)

    Schneider, Yvonne; Zahn, Susann; Rohm, Harald

    In the field of food engineering, cutting is usually classified as a mechanical unit operation dealing with size reduction by applying external forces on a bulk product. Ultrasonic cutting is realized by superpositioning the macroscopic feed motion of the cutting device or of the product with a microscopic vibration of the cutting tool. The excited tool interacts with the product and generates a number of effects. Primary energy concentration in the separation zone and the modification of contact friction along the tool flanks arise from the cyclic loading and are responsible for benefits such as reduced cutting force, smooth cut surface, and reduced product deformation. Secondary effects such as absorption and cavitation originate from the propagation of the sound field in the product and are closely related to chemical and physical properties of the material to be cut. This chapter analyzes interactions between food products and ultrasonic cutting tools and relates these interactions with physical and chemical product properties as well as with processing parameters like cutting velocity, ultrasonic amplitude and frequency, and tool design.

  10. Acoustooptic pulse-echo transducer system

    NASA Technical Reports Server (NTRS)

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

    1983-01-01

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

  11. Ultrasonic Transducers for Fourier Analysis.

    ERIC Educational Resources Information Center

    Greenslade, Thomas B., Jr.

    1995-01-01

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

  12. Development of an Ultrasonic Brake

    NASA Astrophysics Data System (ADS)

    Koyama, Tatsuya; Takemura, Kenjiro; Maeno, Takashi

    In the present paper, a newly developed ultrasonic brake is proposed. The ultrasonic brake can solve problems of conventional passive elements, such as time delay, instability, and large size, by using unique characteristics of ultrasonic motor, as fast response, silent motion, and non-magnetic feature. It can also be designed to be smaller than conventional elements due to its simple structure. The brake locks or releases the rotor by use of ultrasonic levitation phenomenon. First, we have designed the structure of the ultrasonic brake using an equation of ultrasonic levitation phenomenon, results from structural analysis and finite element (FE) analysis of piezoelectric material of the vibrator. Then we have manufactured the ultrasonic brake and have conducted a driving experiment. Finally, we have demonstrated that the maximum levitation force is around 40 N and the friction torque of the ultrasonic brake is up to 0.38 Nm. Moreover, we have confirmed that both response time and torque/inertia ratio of the ultrasonic brake are much more superior to the conventional ones.

  13. Ultrasonic Doppler measurement of renal artery blood flow

    NASA Technical Reports Server (NTRS)

    1974-01-01

    Implantable pulsed Doppler ultrasonic flowmeter development has resulted in designs for application to the aortas of dogs and humans, and to human renal and coronary arteries. A figure of merit was derived for each design, indicating the degree of its precision. An H-array design for transcutaneous observation of blood flow was developed and tested in vitro. Two other simplified designs for the same purpose obviate the need to determine vessel orientation. One of these will be developed in the next time period. Techniques for intraoperative use and for implantation have had mixed success. While satisfactory on large vessels, higher ultrasonic frequencies and alteration of transducer design are required for satisfactory operation of pulsed Doppler flowmeters with small vessels.

  14. Ultrasonic flowmeters: half-century progress report, 1955-2005.

    PubMed

    Lynnworth, L C; Liu, Yi

    2006-12-22

    Ultrasonic flowmeters are one of the fastest-growing technologies within the general field of instruments for process monitoring, measurement and control. Today, acoustic/ultrasonic flowmeters utilize clamp-on and wetted transducers, single and multiple paths, paths on and off the diameter, passive and active principles, contrapropagating transmission, reflection (Doppler), tag correlation, vortex shedding, liquid level sensing of open channel flow or flow in partially-full conduits, and other interactions. Ultrasonic flowmeters are applicable to liquids, gases, and multiphase mixtures, but not without limits. However, no single technology, nor one type of interaction within a technology, can be best for all fluids, occasions and situations. Users who select a particular type of ultrasonic flowmeter over one based on a competing (nonultrasonic) technology often do so for one (or more) of the following reasons: ultrasonic equipment provides a useful measurement whether the fluid is single-phase or not single-phase; equipment is easy to use; flow regime can be laminar, transitional or turbulent; transducers are totally external (no penetration of the pressure boundary); transducers, if not clamp-on, are minimally invasive; no excess pressure drop; when certain conditions are met, accuracy can be better than 0.5%; fast (ms) response; reliable despite temperature extremes; reasonable purchase price, installation, operating and maintenance costs. Sometimes mass flowrate is obtainable. Energy flowrate might be achieved for natural gas and biogas in the near future. How did ultrasonic flowmeters advance in the past fifty years to support such claims? This paper tries to answer this question by looking at ultrasonic flowmeter inventions and publications since 1955, to see how four key problems were solved. PMID:16782156

  15. Center crack detection during continuous casting of aluminum by laser ultrasonic measurements

    NASA Astrophysics Data System (ADS)

    Grün, Hubert; Mitter, Thomas; Roither, Jürgen; Betz, Andreas; Bozorgi, Salar; Burgholzer, Peter

    2014-05-01

    Crack detection during continuous direct chill casting of aluminum is a matter of economics. Determining cracks during production process saves money, energy and raw material. Of course, a non-destructive method is required for this evaluation. Because of temperature concerns conventional ultrasound is not applicable. One non-contact alternative is laser ultrasonics. In laser ultrasonics short laser pulses illuminate the sample. The electromagnetic energy gets absorbed at the surface of the sample and results in local heating followed by expansion. Thereby broadband ultrasonic waves are launched which propagate through the sample and get back reflected or scattered at interfaces (cracks, blowholes,…) like conventional ultrasonic waves. Therefore laser ultrasonics is an alternative thermal infrared technology. By using an interferometer also the detection of the ultrasonic waves at the sample surface is done in a remote manner. During preliminary examinations in the lab by scanning different aluminum studs it was able to distinguish between studs with and without cracks. The prediction of the dimension of the crack by evaluation of the damping of the broadband ultrasonic waves was possible. With simple image reconstruction methods one can localize the crack and give an estimation of its extent and even its shape. Subsequent first measurements using this laser ultrasonic setup during the continuous casting of aluminum were carried out and showed the proof of principle in an industrial environment with elevated temperatures, dust, cooling water and vibrations.

  16. Pulse distortion in single-mode fibers. 3: Chirped pulses.

    PubMed

    Marcuse, D

    1981-10-15

    The theory of pulse distortion in single-mode fibers is extended to include laser sources that suffer a linear wavelength sweep (chirp) during the duration of the pulse. The transmitted pulse is expressed as a Fourier integral whose spectral function is given by an analytical expression in closed form. The rms width of the transmitted pulse is also expressed in closed form. Numerical examples illustrate the influence of the chirp on the shape and rms width of the pulse. A somewhat paradoxical situation exists. A given input pulse can be made arbitrarily short by a sufficiently large amount of chirping, and, after a given fiber length, this chirped pulse returns to its original width. But at this particular distance an unchirped pulse would be only [equiation] times longer. Thus chirping can improve the rate of data transmission by only 40%. PMID:20372221

  17. Column oil agglomeration of fly ash with ultrasonics

    SciTech Connect

    Gray, M.L.; Champagne, K.J.; Soong, Y.; Finseth, D.H.

    1999-07-01

    A promising oil agglomeration process has been developed for the beneficiation of fly ash using a six-foot agglomeration column. Carbon concentrates have been separated from fly ash with yields greater than 60 % and purities of 55 to 74 %. The parameters examined in the study include ultrasonic exposure, pulse rate, frequency, agitation speed, and blade configuration. The effects of the experimental variables on the quality of separation are discussed.

  18. A correlation of air-coupled ultrasonic and thermal diffusivity data for CFCC materials

    SciTech Connect

    Pillai, T.A.K.; Easler, T.E.; Szweda, A.

    1997-01-01

    An air-coupled (non contact) through-transmission ultrasonic investigation has been conducted on 2D multiple ply Nicalon{trademark} SiC fiber/SiNC CFCC panels as a function of number of processing cycles. Corresponding thermal diffusivity imaging was also conducted. The results of the air-coupled ultrasonic investigation correlated with thermal property variations determined via infrared methods. Areas of delaminations were detected and effects of processing cycles were also detected.

  19. Study of microstructure of surface layers of low-carbon steel after turning and ultrasonic finishing

    NASA Astrophysics Data System (ADS)

    Kovalevskaya, Zh. G.; Ivanov, Yu. F.; Perevalova, O. B.; Klimenov, V. A.; Uvarkin, P. V.

    2013-01-01

    Profilometry and optical and transmission electron microscopy are used to examine the microstructure of surface layers of a low-carbon ferrite-pearlite steel subjected to turning and ultrasonic finishing. It is shown that turning peaks and valleys have different microstructures, which stipulates manifestation of technological hereditary when processing surfaces of machined parts. Ultrasonic finishing causes the severe plastic deformation of the surface layer, which favors the elimination of a technological heredity that is acquired during turning.

  20. Ultrasonic monitoring and control in plastic manufacturing

    NASA Astrophysics Data System (ADS)

    Edwards, Russell K.

    In the search for a simple, robust and noninvasive measurement, the use of sound is explored to monitor polymer processing. A new pulsed ultrasonic measurement is developed based on the absorption of ultrasonic energy (AUE) from the plastic. The signal proves to be computationally efficient, robust and simple to use. The sensitivity of the signal is demonstrated in an injection molding process. The AUE signal led to the investigation of continuous sound waves. Different configurations are surveyed. One such configuration is formed by placing a piezoelectric element normal to the cavity face. In this arrangement, standing waves within the mold develop. When tuned to the appropriate frequency; the waves constructively interfere, producing a mechanical resonance within the mold. This configuration is termed Ultrasonic Resonance Monitoring (URM). Plastic presence at the mold face is shown to change the URM signal. Definitions and terms are proposed to explain the concepts and components necessary to realize a URM system. The design of a URM transducer used to monitor the plastic state within the cavity of an injection molding process is presented. An experiment is conducted to study the effects of the plastic on the transducer. Changes in the injection molding parameters are shown to modify the URM profile. In an effort to explain and understand the URM signal, a continuous wave acoustic model is used to identify influential physical parameters. An experiment is conducted to measure the acoustic properties of the plastic during molding. Throughout the molding process, pulsed ultrasonic waveforms are collected while simultaneously measuring the impedance of the URM transducer. The acoustic 3 properties are extracted from the waveforms and used in the model to simulate the response of the URM transducer. Two examples are presented to show how the signal may be used to monitor and control the injection molding process. The first example predicts part weight using features