Effects of Driving Frequency on Propagation Characteristics of Methane - Air Premixed Flame Influenced by Ultrasonic Standing Wave

Energy Technology Data Exchange (ETDEWEB)

Bae, Dae Seok; Kim, Jeong Soo [Pukyong National University, Busan (Korea, Republic of); Seo, Hang Seok [Hanwha Corporation, DaeJeon (Korea, Republic of)

2015-02-15

An experimental study was conducted to scrutinize the influence of the frequency of an ultrasonic standing wave on the variation in the behavior of a methane-air premixed flame. The evolutionary features of the propagating flame were captured by a high-speed camera, and the macroscopic flame behavior, including the flame structure and local velocities, was investigated in detail using a post-processing analysis of the high-speed images. It was found that a structural variation and propagation-velocity augmentation of the methane-air premixed flame were caused by the intervention of the ultrasonic standing wave, which enhanced the combustion reaction. Conclusive evidence for the dependency of the flame behaviors on the driving frequency of the ultrasonic standing wave and equivalence ratio of the reactants is presented.

Phase-coded multi-pulse technique for ultrasonic high-order harmonic imaging of biological tissues in vitro

International Nuclear Information System (INIS)

Ma Qingyu; Zhang Dong; Gong Xiufen; Ma Yong

2007-01-01

Second or higher order harmonic imaging shows significant improvement in image clarity but is degraded by low signal-noise ratio (SNR) compared with fundamental imaging. This paper presents a phase-coded multi-pulse technique to provide the enhancement of SNR for the desired high-order harmonic ultrasonic imaging. In this technique, with N phase-coded pulses excitation, the received Nth harmonic signal is enhanced by 20 log 10 N dB compared with that in the single-pulse mode, whereas the fundamental and other order harmonic components are efficiently suppressed to reduce image confusion. The principle of this technique is theoretically discussed based on the theory of the finite amplitude sound waves, and examined by measurements of the axial and lateral beam profiles as well as the phase shift of the harmonics. In the experimental imaging for two biological tissue specimens, a plane piston source at 2 MHz is used to transmit a sequence of multiple pulses with equidistant phase shift. The second to fifth harmonic images are obtained using this technique with N = 2 to 5, and compared with the images obtained at the fundamental frequency. Results demonstrate that this technique of relying on higher order harmonics seems to provide a better resolution and contrast of ultrasonic images

Frequency and amplitude dependences of molding accuracy in ultrasonic nanoimprint technology

International Nuclear Information System (INIS)

Mekaru, Harutaka; Takahashi, Masaharu

2009-01-01

We use neither a heater nor ultraviolet lights, and are researching and developing an ultrasonic nanoimprint as a new nano-patterning technology. In our ultrasonic nanoimprint technology, ultrasonic vibration is not used as a heat generator instead of the heater. A mold is connected with an ultrasonic generator, and mold patterns are pushed down and pulled up at a high speed into a thermoplastic. Frictional heat is generated by ultrasonic vibration between mold patterns and thermoplastic patterns formed by an initial contact force. However, because frictional heat occurs locally, the whole mold is not heated. Therefore, a molding material can be comprehensively processed at room temperature. A magnetostriction actuator was built into our ultrasonic nanoimprint system as an ultrasonic generator, and the frequency and amplitude can be changed between dc–10 kHz and 0–4 µm, respectively. First, the ultrasonic nanoimprint was experimented by using this system on polyethylene terephthalate (PET, T g = 69 °C), whose the glass transition temperature (T g ) is comparatively low in engineering plastics, and it was ascertained that the most suitable elastic material for this technique was an ethyl urethane rubber. In addition, we used a changeable frequency of the magnetostriction actuator, and nano-patterns in an electroformed-Ni mold were transferred to a 0.5 mm thick sheet of PET, polymethylmethacrylate (PMMA) and polycarbonate (PC), which are typical engineering plastics, under variable molding conditions. The frequency and amplitude dependence of ultrasonic vibration to the molding accuracy were investigated by measuring depth and width of imprinted patterns. As a result, regardless of the molding material, the imprinted depth was changed drastically when the frequency exceeded 5 kHz. On the other hand, when the amplitude of ultrasonic vibration grew, the imprinted depth gradually deepened. Influence of the frequency and amplitude of ultrasonic vibration was not

Detection of Fatigue Damage by Using High Frequency Nonlinear Laser Ultrasonic Signals

International Nuclear Information System (INIS)

Park, Seung Kyu; Park, Nak Kyu; Baik, Sung Hoon; Cheong, Yong Moo; Cha, Byung Heon

2012-01-01

The detection of fatigue damage for the components of a nuclear power plant is one of key techniques to prevent a catastrophic accident and the subsequent severe losses. Specifically, it is preferred to detect at an early stage of the fatigue damage. If the fatigue damage that is in danger of growing into a fracture is accurately detected, an appropriate treatment could be carried out to improve the condition. Although most engineers and designers take precautions against fatigue, some breakdowns of nuclear power plant components still occur due to fatigue damage. It is considered that ultrasound testing technique is the most promising method to detect the fatigue damage in many nondestructive testing methods. Laser ultrasound has attracted attention as a noncontact testing technique. Especially, laser ultrasonic signal has wide band frequency spectrum which can provide more accurate information for a testing material. The conventional linear ultrasonic technique is sensitive to gross defects or opened cracks whereas it is less sensitive to evenly distributed micro-cracks or degradation. An alternative technique to overcome this limitation is nonlinear ultrasound. The principal difference between linear and nonlinear technique is that in the latter the existence and characteristics of defects are often related to an acoustic signal whose frequency differs from that of the input signal. This is related to the radiation and propagation of finite amplitude, especially high power, ultrasound and its interaction with discontinuities, such as cracks, interfaces and voids. Since material failure or degradation is usually preceded by some kind of nonlinear mechanical behavior before significant plastic deformation or material damage occurs. The presence of nonlinear terms in the wave equation causes intense acoustic waves to generate new waves at frequencies which are multiples of the initial sound wave frequency. The nonlinear effect can exert a strong effect on the

Under sodium ultrasonic imaging system for PFBR

International Nuclear Information System (INIS)

Patankar, V.H.; Lalwani, S.K.; Agashe, A.A.

2014-01-01

Under Sodium UltraSonic Scanner (USUSS) has been developed to detect the growth and protrusion of fuel sub-assemblies of PFBR, submerged in liquid sodium by using the ultrasonic imaging technique during reactor shut-down when liquid sodium is at 180 ℃. The imaging is carried out prior to every Fuel handling operation. Electronics Division, BARC has designed and developed an 8-Channel Ultrasonic Imaging System (UIS) which consists of 4 downward viewing and 4 side viewing ultrasonic transducers alongwith pulser-receiver, signal processing electronics hardware and software. An automated mechanical scanner developed by IGCAR houses sodium immersible transducers to image the fuel sub assemblies. The system has been successfully tested with dummy protruding and grown FSAs, submerged under liquid sodium. Such ultrasonic imaging systems are not available to India from international market. The USUSS developed indigenously has all the features available in similar systems developed by other countries. After every imaging campaign, the mechanical scanner containing ultrasonic transducers is stored in the Argon filled storage-pit. Before every campaign of USUSS, it is necessary to check the healthiness of the sodium immersible and contaminated ultrasonic transducers, as the under-sodium scanner is decontaminated once in five years. For this purpose, a novel Non Contact Ultrasonic Inspection System (NCUIS) has been designed and developed by Electronics Division, BARC to check the functionality of the high-temperature and contaminated transducers of USUSS, using air-coupled ultrasonic technique. (author)

Monitoring of corrosion damage using high-frequency guided ultrasonic waves

Science.gov (United States)

Chew, D.; Fromme, P.

2015-03-01

Due to adverse environmental conditions corrosion can develop during the life cycle of industrial structures, e.g., offshore oil platforms, ships, and desalination plants. Both pitting corrosion and generalized corrosion leading to wall thickness loss can cause the degradation of the integrity and load bearing capacity of the structure. Structural health monitoring of corrosion damage in difficult to access areas can in principle be achieved using high frequency guided waves propagating along the structure from accessible areas. Using standard ultrasonic transducers with single sided access to the structure, high frequency guided wave modes were generated that penetrate through the complete thickness of the structure. Wall thickness reduction was induced using accelerated corrosion in a salt water bath. The corrosion damage was monitored based on the effect on the wave propagation and interference of the different modes. The change in the wave interference was quantified based on an analysis in the frequency domain (Fourier transform) and was found to match well with theoretical predictions for the wall thickness loss. High frequency guided waves have the potential for corrosion damage monitoring at critical and difficult to access locations from a stand-off distance.

Ultrasonic colour Doppler imaging

DEFF Research Database (Denmark)

Evans, David H; Jensen, Jørgen Arendt; Nielsen, Michael Bachmann

2011-01-01

Ultrasonic colour Doppler is an imaging technique that combines anatomical information derived using ultrasonic pulse-echo techniques with velocity information derived using ultrasonic Doppler techniques to generate colour-coded maps of tissue velocity superimposed on grey-scale images of tissue...... anatomy. The most common use of the technique is to image the movement of blood through the heart, arteries and veins, but it may also be used to image the motion of solid tissues such as the heart walls. Colour Doppler imaging is now provided on almost all commercial ultrasound machines, and has been...

Corrosion monitoring using high-frequency guided ultrasonic waves

Science.gov (United States)

Fromme, Paul

2014-02-01

Corrosion develops due to adverse environmental conditions during the life cycle of a range of industrial structures, e.g., offshore oil platforms, ships, and desalination plants. Both pitting corrosion and generalized corrosion leading to wall thickness loss can cause the degradation of the structural integrity. The nondestructive detection and monitoring of corrosion damage in difficult to access areas can be achieved using high frequency guided waves propagating along the structure from accessible areas. Using standard ultrasonic transducers with single sided access to the structure, guided wave modes were generated that penetrate through the complete thickness of the structure. The wave propagation and interference of the different guided wave modes depends on the thickness of the structure. Laboratory experiments were conducted and the wall thickness reduced by consecutive milling of the steel structure. Further measurements were conducted using accelerated corrosion in a salt water bath and the damage severity monitored. From the measured signal change due to the wave mode interference the wall thickness reduction was monitored. The high frequency guided waves have the potential for corrosion damage monitoring at critical and difficult to access locations from a stand-off distance.

A Brazing Defect Detection Using an Ultrasonic Infrared Imaging Inspection

Energy Technology Data Exchange (ETDEWEB)

Cho, Jai Wan; Choi, Young Soo; Jung, Seung Ho; Jung, Hyun Kyu [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

2007-10-15

When a high-energy ultrasound propagates through a solid body that contains a crack or a delamination, the two faces of the defect do not ordinarily vibrate in unison, and dissipative phenomena such as friction, rubbing and clapping between the faces will convert some of the vibrational energy to heat. By combining this heating effect with infrared imaging, one can detect a subsurface defect in material in real time. In this paper a realtime detection of the brazing defect of thin Inconel plates using the UIR (ultrasonic infrared imaging) technology is described. A low frequency (23 kHz) ultrasonic transducer was used to infuse the welded Inconel plates with a short pulse of sound for 280 ms. The ultrasonic source has a maximum power of 2 kW. The surface temperature of the area under inspection is imaged by an infrared camera that is coupled to a fast frame grabber in a computer. The hot spots, which are a small area around the bound between the two faces of the Inconel plates near the defective brazing point and heated up highly, are observed. And the weak thermal signal is observed at the defect position of brazed plate also. Using the image processing technology such as background subtraction average and image enhancement using histogram equalization, the position of defective brazing regions in the thin Inconel plates can be located certainly

Development and evaluation of a novel low power, high frequency piezoelectric-based ultrasonic reactor for intensifying the transesterification reaction

Directory of Open Access Journals (Sweden)

Mortaza Aghbashlo

2016-12-01

Full Text Available In this study, a novel low power, high frequency piezoelectric-based ultrasonic reactor was developed and evaluated for intensifying the transesterification process. The reactor was equipped with an automatic temperature control system, a heating element, a precise temperature sensor, and a piezoelectric-based ultrasonic module. The conversion efficiency and specific energy consumption of the reactor were examined under different operational conditions, i.e., reactor temperature (40‒60 °C, ultrasonication time (6‒10 min, and alcohol/oil molar ratio (4:1‒8:1. Transesterification of waste cooking oil (WCO was performed in the presence of a base-catalyst (potassium hydroxide using methanol. According to the obtained results, alcohol/oil molar ratio of 6:1, ultrasonication time of 10 min, and reactor temperature of 60 °C were found as the best operational conditions. Under these conditions, the reactor converted WCO to biodiesel with a conversion efficiency of 97.12%, meeting the ASTM standard satisfactorily, while the lowest specific energy consumption of 378 kJ/kg was also recorded. It should be noted that the highest conversion efficiency of 99.3 %, achieved at reactor temperature of 60 °C, ultrasonication time of 10 min, and alcohol/oil molar ratio of 8:1, was not favorable as the associated specific energy consumption was higher at 395 kJ/kg. Overall, the low power, high frequency piezoelectric-based ultrasonic module could be regarded as an efficient and reliable technology for intensifying the transesterification process in terms of energy consumption, conversion efficiency, and processing time, in comparison with high power, low frequency ultrasonic system reported previously. Finally, this technology could also be considered for designing, developing, and retrofitting chemical reactors being employed for non-biofuel applications as well.

Ultrasonic colour Doppler imaging

DEFF Research Database (Denmark)

Evans, David H.; Jensen, Jørgen Arendt; Nielsen, Michael Bachmann

2011-01-01

Ultrasonic colour Doppler is an imaging technique that combines anatomical information derived using ultrasonic pulse-echo techniques with velocity information derived using ultrasonic Doppler techniques to generate colour-coded maps of tissue velocity superimposed on grey-scale images of tissue...... anatomy. The most common use of the technique is to image the movement of blood through the heart, arteries and veins, but it may also be used to image the motion of solid tissues such as the heart walls. Colour Doppler imaging is now provided on almost all commercial ultrasound machines, and has been...... vectors. This review briefly introduces the principles behind colour Doppler imaging and describes some clinical applications. It then describes the basic components of conventional colour Doppler systems and the methods used to derive velocity information from the ultrasound signal. Next, a number of new...

Nonlinear propagation in ultrasonic fields: measurements, modelling and harmonic imaging.

Science.gov (United States)

Humphrey, V F

2000-03-01

In high amplitude ultrasonic fields, such as those used in medical ultrasound, nonlinear propagation can result in waveform distortion and the generation of harmonics of the initial frequency. In the nearfield of a transducer this process is complicated by diffraction effects associated with the source. The results of a programme to study the nonlinear propagation in the fields of circular, focused and rectangular transducers are described, and comparisons made with numerical predictions obtained using a finite difference solution to the Khokhlov-Zabolotskaya-Kuznetsov (or KZK) equation. These results are extended to consider nonlinear propagation in tissue-like media and the implications for ultrasonic measurements and ultrasonic heating are discussed. The narrower beamwidths and reduced side-lobe levels of the harmonic beams are illustrated and the use of harmonics to form diagnostic images with improved resolution is described.

Comparison of pulse characteristic of low frequency ultrasonic probes for concrete application

International Nuclear Information System (INIS)

Amry Amin Abas; Suhairy Sani; Muhammad Pauzi Ismail

2006-01-01

Ultrasonic testing of concrete or large volume of composites usually is done in low frequency range. To obtain low frequency pulse, a low frequency pulser/receiver is used attached to a low frequency probe as transmitter/receiver. Concrete is highly attenuative and a high energy pulse is essential to ensure good penetration of test samples. High energy pulse can be obtained by producing low frequency ultrasonic waves.To achieve high penetration in concrete, a low frequency probe is fabricated with the centre frequency lying at around 100 kHz. The probe is fabricated with single crystal of 18 mm thickness without any backing material to obtain wider pulse and higher pulse power. Then, comparison of pulse characteristic is done between the fabricated probe and a commercially available probe to determine the quality of the probe fabricated. (Author)

High-frequency annular array with coaxial illumination for dual-modality ultrasonic and photoacoustic imaging

Science.gov (United States)

Filoux, Erwan; Sampathkumar, Ashwin; Chitnis, Parag V.; Aristizábal, Orlando; Ketterling, Jeffrey A.

2013-05-01

This paper presents a combined ultrasound and photoacoustic (PA) imaging (PAI) system used to obtain high-quality, co-registered images of mouse-embryo anatomy and vasculature. High-frequency ultrasound (HFU, >20 MHz) is utilized to obtain high-resolution anatomical images of small animals while PAI provides high-contrast images of the vascular network. The imaging system is based on a 40 MHz, 5-element, 6 mm aperture annular-array transducer with a 800 μm diameter hole through its central element. The transducer was integrated in a cage-plate assembly allowing for a collimated laser beam to pass through the hole so that the optical and acoustic beams were collinear. The assembly was mounted on a two-axis, motorized stage to enable the simultaneous acquisition of co-registered HFU and PA volumetric data. Data were collected from all five elements in receive and a synthetic-focusing algorithm was applied in post-processing to beamform the data and increase the spatial resolution and depth-of-field (DOF) of the HFU and PA images. Phantom measurements showed that the system could achieve high-resolution images (down to 90 μm for HFU and 150 μm for PAI) and a large DOF of >8 mm. Volume renderings of a mouse embryo showed that the scanner allowed for visualizing morphologically precise anatomy of the entire embryo along with corresponding co-registered vasculature. Major head vessels, such as the superior sagittal sinus or rostral vein, were clearly identified as well as limb bud vasculature.

The maturity characterization of orange fruit by using high frequency ultrasonic echo pulse method

International Nuclear Information System (INIS)

Aboudaoud, I; Faiz, B; Aassif, E; Izbaim, D; Abassi, D; Malainine, M; Azergui, M; Moudden, A

2012-01-01

In this present work, we develop a new ultrasonic echo pulse method in order to study the feasibility of maturity assessment of orange fruit. This study concerns two varieties of orange (Navel and Mandarin) which are the most harvested in the region of Souss-Massa-Drāa in Morocco. We worked in the range of high frequencies by the means of a focusing transducer with 20MHz as a central frequency. By taking into account the strong attenuation of the ultrasounds in the texture of fruits and vegetables, we limited our study only to the external layer of orange peel. This control is based mainly on the measure of the ultrasonic parameters eventually velocity and attenuation in order to check the aptitude of this technique to detect the maturity degree of the fruit without passing by penetrometric and biochemical measurements which are generally destructives but the mostly correlated with human perception concerning the firmness of the fruit.

Design and Manufacture an Ultrasonic Dispersion System with Automatic Frequency Adjusting Property

Directory of Open Access Journals (Sweden)

Herlina ABDUL RAHIM

2011-03-01

Full Text Available This paper a novel ultrasonic dispersion system for the cleaning application or dispersing of particles which are mixed in liquid has been proposed. The frequency band of designed system is 30 kHz so that the frequency of ultrasonic wave sweeps from 30 kHz to 60 kHz with 100 Hz steps. One of the superiority of manufactured system in compare with the other similar systems which are available in markets is that this system can transfer the maximum and optimum energy of ultrasonic wave inside the liquid tank with the high efficiency in the whole of the usage time of the system. The used ultrasonic transducers in this system as the generator of ultrasonic wave is the type of air coupled ceramic ultrasonic piezoelectric with the nominal maximum power 50 Watt. The frequency characteristic of applied piezoelectric is that it produces the maximum amplitude of ultrasonic wave on the resonance frequency, so this system is designed to work on resonance frequency of piezoelectric, continuously. This is done by the use of control system which is consisted of two major parts, sensing part and controlling part. The manufactured ultrasonic dispersion system is consisted of 9 piezoelectrics so that it can produce 450 watt ultrasonic energy, totally. The main purpose of this project is to produce a safety system especially for fatigue car driver so as to prevent from accidents. The statistic on road fatality shows that human error constitute of 64.84 % road accidents fatality and 17.4 % due to technical factors. These systems encompassed the approach of hand pressure applied on the steering wheel. The steering will be installed with pressure sensors. At the same time these sensors can be used to measure gripping force while driving.

Paternal kin recognition in the high frequency / ultrasonic range in a solitary foraging mammal

Directory of Open Access Journals (Sweden)

Kessler Sharon E

2012-11-01

Full Text Available Abstract Background Kin selection is a driving force in the evolution of mammalian social complexity. Recognition of paternal kin using vocalizations occurs in taxa with cohesive, complex social groups. This is the first investigation of paternal kin recognition via vocalizations in a small-brained, solitary foraging mammal, the grey mouse lemur (Microcebus murinus, a frequent model for ancestral primates. We analyzed the high frequency/ultrasonic male advertisement (courtship call and alarm call. Results Multi-parametric analyses of the calls’ acoustic parameters and discriminant function analyses showed that advertisement calls, but not alarm calls, contain patrilineal signatures. Playback experiments controlling for familiarity showed that females paid more attention to advertisement calls from unrelated males than from their fathers. Reactions to alarm calls from unrelated males and fathers did not differ. Conclusions 1 Findings provide the first evidence of paternal kin recognition via vocalizations in a small-brained, solitarily foraging mammal. 2 High predation, small body size, and dispersed social systems may select for acoustic paternal kin recognition in the high frequency/ultrasonic ranges, thus limiting risks of inbreeding and eavesdropping by predators or conspecific competitors. 3 Paternal kin recognition via vocalizations in mammals is not dependent upon a large brain and high social complexity, but may already have been an integral part of the dispersed social networks from which more complex, kin-based sociality emerged.

Mode Identification of Guided Ultrasonic Wave using Time- Frequency Algorithm

International Nuclear Information System (INIS)

Yoon, Byung Sik; Yang, Seung Han; Cho, Yong Sang; Kim, Yong Sik; Lee, Hee Jong

2007-01-01

The ultrasonic guided waves are waves whose propagation characteristics depend on structural thickness and shape such as those in plates, tubes, rods, and embedded layers. If the angle of incidence or the frequency of sound is adjusted properly, the reflected and refracted energy within the structure will constructively interfere, thereby launching the guided wave. Because these waves penetrate the entire thickness of the tube and propagate parallel to the surface, a large portion of the material can be examined from a single transducer location. The guided ultrasonic wave has various merits like above. But various kind of modes are propagating through the entire thickness, so we don't know the which mode is received. Most of applications are limited from mode selection and mode identification. So the mode identification is very important process for guided ultrasonic inspection application. In this study, various time-frequency analysis methodologies are developed and compared for mode identification tool of guided ultrasonic signal. For this study, a high power tone-burst ultrasonic system set up for the generation and receive of guided waves. And artificial notches were fabricated on the Aluminum plate for the experiment on the mode identification

Effect of ultrasonic intensity and frequency on oil/heavy-oil recovery from different wettability rocks

Energy Technology Data Exchange (ETDEWEB)

Naderi, K.; Babadagli, T. [Society of Petroleum Engineers, Canadian Section, Calgary, AB (Canada)]|[Alberta Univ., Edmonton, AB (Canada)

2008-10-15

This study identified the mechanisms that are responsible for additional oil recovery that is often observed following an earthquake. It focused on the theory that harmonics of low frequency waves create high frequency waves as they penetrate into rock formations. A series of experiments were conducted on oil-wet rocks with high oil viscosities. The objective was to better understand how ultrasonic energy affects oil recovery at core and pore scale. Cylindrical sandstone cores were placed in imbibition cells to examine how the presence of initial water saturation can affect recovery, and how the recovery changes for different oil viscosities. An increase in oil recovery was observed with ultrasonic energy in all cases. The additional recovery with ultrasonic energy lessened as the oil viscosity increased. Ultrasonic intensity and frequency were shown to be critical to the performance, which is important since ultrasonic waves have limited penetration into porous medium. This is a key disadvantage for commercializing this promising process for well stimulation. Therefore, the authors designed a set-up to measure the ultrasonic energy penetration capacity in different media, notably air, water and slurry. The set-up could identify which types of reservoirs are most suitable for ultrasonic application. Imbibition experiments revealed that ultrasonic radiation increases recovery, and is much more significant in oil wet cases, where initial water saturation facilitate oil recovery. Higher frequency showed a higher rate of recovery compared to lower frequency, but the ultimate recovery was not changed substantially. 46 refs., 1 tab., 16 figs.

MOSFET-based high voltage short pulse generator for ultrasonic transducer excitation

Science.gov (United States)

Hidayat, Darmawan; Setianto, Syafei, Nendi Suhendi; Wibawa, Bambang Mukti

2018-02-01

This paper presents the generation of a high-voltage short pulse for the excitation of high frequency ultrasonic transducers. This is highly required in the purpose of various ultrasonic-based evaluations, particularly when high resolution measurement is necessary. A high voltage (+760 V) DC voltage source was pulsated by an ultrafast switching MOSFET which was driven by a pulse generator circuit consisting of an astable multivibrator, a one-shot multivibrator with Schmitt trigger input and a high current MOSFET driver. The generated pulses excited a 200-kHz and a 1-MHz ultrasonic transducers and tested in the transmission mode propagation to evaluate the performances of the generated pulse. The test results showed the generator were able to produce negative spike pulses up to -760 V voltage with the shortest time-width of 107.1 nanosecond. The transmission-received ultrasonic waves show frequency oscillation at 200 and 961 kHz and their amplitudes varied with the voltage of excitation pulse. These results conclude that the developed pulse generator is applicable to excite transducer for the generation of high frequency ultrasonic waves.

Stand-alone front-end system for high- frequency, high-frame-rate coded excitation ultrasonic imaging.

Science.gov (United States)

Park, Jinhyoung; Hu, Changhong; Shung, K Kirk

2011-12-01

A stand-alone front-end system for high-frequency coded excitation imaging was implemented to achieve a wider dynamic range. The system included an arbitrary waveform amplifier, an arbitrary waveform generator, an analog receiver, a motor position interpreter, a motor controller and power supplies. The digitized arbitrary waveforms at a sampling rate of 150 MHz could be programmed and converted to an analog signal. The pulse was subsequently amplified to excite an ultrasound transducer, and the maximum output voltage level achieved was 120 V(pp). The bandwidth of the arbitrary waveform amplifier was from 1 to 70 MHz. The noise figure of the preamplifier was less than 7.7 dB and the bandwidth was 95 MHz. Phantoms and biological tissues were imaged at a frame rate as high as 68 frames per second (fps) to evaluate the performance of the system. During the measurement, 40-MHz lithium niobate (LiNbO(3)) single-element lightweight (<;0.28 g) transducers were utilized. The wire target measure- ment showed that the -6-dB axial resolution of a chirp-coded excitation was 50 μm and lateral resolution was 120 μm. The echo signal-to-noise ratios were found to be 54 and 65 dB for the short burst and coded excitation, respectively. The contrast resolution in a sphere phantom study was estimated to be 24 dB for the chirp-coded excitation and 15 dB for the short burst modes. In an in vivo study, zebrafish and mouse hearts were imaged. Boundaries of the zebrafish heart in the image could be differentiated because of the low-noise operation of the implemented system. In mouse heart images, valves and chambers could be readily visualized with the coded excitation.

Development of fuel number reader by ultrasonic imaging techniques

International Nuclear Information System (INIS)

Omote, T.; Yoshida, T.

1991-01-01

This paper reports on a spent fuel ID number reader using ultrasonic imaging techniques that has been developed to realize efficient and automatic verification of fuel numbers, thereby to reduce mental load and radiation exposure for operators engaged in the verification task. The ultrasonic imaging techniques for automatic fuel number recognition are described. High-speed and high reliability imaging of the spent fuel ID number are obtained by using linear array type ultrasonic probe. The ultrasonic wave is scanned by switching array probe in vertical direction, and scanned mechanically in horizontal direction. Time for imaging of spent fuel ID number on assembly was confirmed less than three seconds by these techniques. And it can recognize spent fuel ID number even if spent fuel ID number can not be visualized by an optical method because of depositing fuel number regions by soft card. In order to recognize spent fuel ID number more rapidly and more reliably, coded fuel number expressed by plural separate recesses form is developed. Every coded fuel number consists of six small holes (about 1 mm dia.) and can be marked adjacent to the existing fuel number expressed by letters and numbers

Detection of tissue coagulation by decorrelation of ultrasonic echo signals in cavitation-enhanced high-intensity focused ultrasound treatment.

Science.gov (United States)

Yoshizawa, Shin; Matsuura, Keiko; Takagi, Ryo; Yamamoto, Mariko; Umemura, Shin-Ichiro

2016-01-01

A noninvasive technique to monitor thermal lesion formation is necessary to ensure the accuracy and safety of high-intensity focused ultrasound (HIFU) treatment. The purpose of this study is to ultrasonically detect the tissue change due to thermal coagulation in the HIFU treatment enhanced by cavitation microbubbles. An ultrasound imaging probe transmitted plane waves at a center frequency of 4.5 MHz. Ultrasonic radio-frequency (RF) echo signals during HIFU exposure at a frequency of 1.2 MHz were acquired. Cross-correlation coefficients were calculated between in-phase and quadrature (IQ) data of two B-mode images with an interval time of 50 and 500 ms for the estimation of the region of cavitation and coagulation, respectively. Pathological examination of the coagulated tissue was also performed to compare with the corresponding ultrasonically detected coagulation region. The distribution of minimum hold cross-correlation coefficient between two sets of IQ data with 50-ms intervals was compared with a pulse inversion (PI) image. The regions with low cross-correlation coefficients approximately corresponded to those with high brightness in the PI image. The regions with low cross-correlation coefficients in 500-ms intervals showed a good agreement with those with significant change in histology. The results show that the regions of coagulation and cavitation could be ultrasonically detected as those with low cross-correlation coefficients between RF frames with certain intervals. This method will contribute to improve the safety and accuracy of the HIFU treatment enhanced by cavitation microbubbles.

Time reversal for ultrasonic transcranial surgery and echographic imaging

Science.gov (United States)

Tanter, Mickael; Aubry, Jean-Francois; Vignon, Francois; Fink, Mathias

2005-09-01

High-intensity focused ultrasound (HIFU) is able to induce non-invasively controlled and selective destruction of tissues by focusing ultrasonic beams within organs, analogous to a magnifying glass that concentrates enough sunlight to burn a hole in paper. The brain is an attractive organ in which to perform ultrasonic tissue ablation, but such an application has been hampered by the strong defocusing effect of the skull bone. Our group has been involved in this topic for several years, providing proofs of concept and proposing technological solutions to this problem. Thanks to a high-power time-reversal mirror, presented here are in vivo thermal lesions induced through the skull of 12 sheep. Thermal lesions were confirmed by T2-weighted magnetic resonance post-treatment images and histological examination. These results provide striking evidence that noninvasive ultrasound brain surgery is feasible. A recent approach for high-resolution brain ultrasonic imaging will also be discussed with a skull aberration correction technique based on twin arrays technology. The correction of transcranial ultrasonic images is implemented on a new generation of time-reversal mirrors relying on a fully programmable transmit and receive beamformer.

A Low-Power High-Dynamic-Range Receiver System for In-Probe 3-D Ultrasonic Imaging.

Science.gov (United States)

Attarzadeh, Hourieh; Xu, Ye; Ytterdal, Trond

2017-10-01

In this paper, a dual-mode low-power, high dynamic-range receiver circuit is designed for the interface with a capacitive micromachined ultrasonic transducer. The proposed ultrasound receiver chip enables the development of an in-probe digital beamforming imaging system. The flexibility of having two operation modes offers a high dynamic range with minimum power sacrifice. A prototype of the chip containing one receive channel, with one variable transimpedance amplifier (TIA) and one analog to digital converter (ADC) circuit is implemented. Combining variable gain TIA functionality with ADC gain settings achieves an enhanced overall high dynamic range, while low power dissipation is maintained. The chip is designed and fabricated in a 65 nm standard CMOS process technology. The test chip occupies an area of 76[Formula: see text] 170 [Formula: see text]. A total average power range of 60-240 [Formula: see text] for a sampling frequency of 30 MHz, and a center frequency of 5 MHz is measured. An instantaneous dynamic range of 50.5 dB with an overall dynamic range of 72 dB is obtained from the receiver circuit.

Ultrasonic imaging of projected components of PFBR

Energy Technology Data Exchange (ETDEWEB)

Sylvia, J.I., E-mail: sylvia@igcar.gov.in [Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu (India); Jeyan, M.R.; Anbucheliyan, M.; Asokane, C.; Babu, V. Rajan; Babu, B.; Rajan, K.K.; Velusamy, K.; Jayakumar, T. [Indira Gandhi Centre for Atomic Research, Kalpakkam 603 102, Tamil Nadu (India)

2013-05-15

Highlights: ► Under sodium ultrasonic scanner in PFBR is for detecting protruding objects. ► Feasibility study for detecting Absorber rods and its drive mechanisms. ► Developed in-house PC based ultrasonic imaging system. ► Different case studies were carried out on simulated ARDM's. ► Implemented the experimental results to PFBR application. -- Abstract: The 500 MWe, sodium cooled, Prototype Fast Breeder Reactor (PFBR) is under advanced stage of construction at Kalpakkam in India. Opacity of sodium restricts visual inspection of components immersed in sodium by optical means. Ultrasonic wave passes through sodium hence ultrasonic techniques using under sodium ultrasonic scanners are developed to obtain under sodium images. The main objective of such an Under Sodium Ultrasonic Scanner (USUSS) for Prototype Fast Breeder Reactor (PFBR) is to detect and ensure that no core Sub Assembly (SA) or Absorber Rod or its Drive Mechanism is protruded in the above core plenum before starting the fuel handling operation. Hence, it is necessary to detect and locate the object, if it is protruding the above core plenum. To study the feasibility of detecting the absorber rods and their drive mechanisms using direct ultrasonic imaging technique, experiments were carried out for different orientations and profiles of the projected components in a 5 m diameter water tank. The in-house developed PC based ultrasonic scanning system is used for acquisition and analysis of data. The pseudo three dimensional color images obtained are discussed and the results are applicable for PFBR. This paper gives the details of the features of the absorber rods and their drive mechanisms, their orientation in the reactor core, experimental setup, PC based ultrasonic scanning system, ultrasonic images and the discussion on the results.

Defect detection and sizing in ultrasonic imaging

International Nuclear Information System (INIS)

Moysan, J.; Benoist, P.; Chapuis, N.; Magnin, I.

1991-01-01

This paper introduces imaging processing developed with the SPARTACUS system in the field of ultrasonic testing. The aim of the imaging processing is to detect and to separate defects echoes from background noise. Image segmentation and particularities of ultrasonic images are the base of studied methods. 4 figs.; 6 refs [fr

Evaluation of Die-Attach Bonding Using High-Frequency Ultrasonic Energy for High-Temperature Application

Science.gov (United States)

Lee, Jong-Bum; Aw, Jie-Li; Rhee, Min-Woo

2014-09-01

Room-temperature die-attach bonding using ultrasonic energy was evaluated on Cu/In and Cu/Sn-3Ag metal stacks. The In and Sn-3Ag layers have much lower melting temperatures than the base material (Cu) and can be melted through the heat generated during ultrasonic bonding, forming intermetallic compounds (IMCs). Samples were bonded using different ultrasonic powers, bonding times, and forces and subsequently aged at 300°C for 500 h. After aging, die shear testing was performed and the fracture surfaces were inspected by scanning electron microscopy. Results showed that the shear strength of Cu/In joints reached an upper plateau after 100 h of thermal aging and remained stable with aging time, whereas that of the Cu/Sn-3Ag joints decreased with increasing aging time. η-Cu7In4 and (Cu,Au)11In9 IMCs were observed at the Cu/In joint, while Cu3Sn and (Ag,Cu)3Sn IMCs were found at the Cu/Sn-3Ag joint after reliability testing. As Cu-based IMCs have high melting temperatures, they are highly suitable for use in high-temperature electronics, but can be formed at room temperature using an ultrasonic approach.

High Frequency Longitudinal Damped Vibrations of a Cylindrical Ultrasonic Transducer

Directory of Open Access Journals (Sweden)

Mihai Valentin Predoi

2014-01-01

Full Text Available Ultrasonic piezoelectric transducers used in classical nondestructive testing are producing in general longitudinal vibrations in the MHz range. A simple mechanical model of these transducers would be very useful for wave propagation numerical simulations, avoiding the existing complicated models in which the real components of the transducer are modeled by finite elements. The classical model for longitudinal vibrations is not adequate because the generated longitudinal wave is not dispersive, the velocity being the same at any frequency. We have adopted the Rayleigh-Bishop model, which avoids these limitations, even if it is not converging to the first but to the second exact longitudinal mode in an elastic rod, as obtained from the complicated Pochhammer-Chree equations. Since real transducers have significant vibrations damping, we have introduced a damping term in the Rayleigh-Bishop model, increasing the imaginary part and keeping almost identical real part of the wavenumber. Common transducers produce amplitude modulated signals, completely attenuated after several periods. This can be modeled by two close frequencies, producing a “beat” phenomenon, superposed on the high damping. For this reason, we introduce a two-rod Rayleigh-Bishop model with damping. Agreement with measured normal velocity on the transducer free surface is encouraging for continuation of the research.

High frequency transducer for vessel imaging based on lead-free Mn-doped (K0.44Na0.56)NbO3 single crystal

Science.gov (United States)

Ma, Jinpeng; Xue, Saidong; Zhao, Xiangyong; Wang, Feifei; Tang, Yanxue; Duan, Zhihua; Wang, Tao; Shi, Wangzhou; Yue, Qingwen; Zhou, Huifang; Luo, Haosu; Fang, Bijun

2017-08-01

We report a high frequency ultrasonic transducer up to 50 MHz for vessel imaging based on a lead-free (K0.44Na0.56)NbO3-0.5 mol. % Mn (Mn-KNN) single crystal, which has a high electromechanical coupling coefficient kt of 0.64 and a large thickness frequency constant Nt of 3210 kHz . mm. The Krimholtz, Leedom, and Mattaei (KLM) equivalent circuit model was utilized to simulate and optimize the pulse-echo response combined with PiezoCAD software. Theoretically, a high -6 dB bandwidth of 74.94% was obtained at a center frequency of 50.47 MHz and optimized matching conditions. The experimental results showed a center frequency of 51.8 MHz with a -6 dB bandwidth of 70.2%. The excellent global performance makes this lead-free single-crystal transducer quite potential in an environmentally friendly vessel imaging transducer.

Ultrasonic imaging of metastatic carcinoma in thyroid gland

International Nuclear Information System (INIS)

Bai Ling; Yang Tao; Tang Ying; Mao Jingning; Chen Wei; Wang Wei

2008-01-01

Objectives: To explore the ultrasonic findings of metastatic thyroid carcinoma and to evaluate the diagnostic value of the ultrasonic imaging for patients with metastatic thyroid neoplasm. Methods: The ultrasonic imaging characteristics of ten patients who were diagnosed with metastatic thyroid carcinoma were retrospectively analyzed. In all the cases, fine-needle aspiration cytology (FNAC) of the thyroid was performed during the clinical diagnosis. Results: The ultrasonic images of the ten patients fell into four types: multiple nodules in the thyroid, single nodule in the thyroid, diffuse calcification and heterogeneous echo. Seven cases showed speckled calcific foci. Abnormal blood flow signal was found in 9 cases. Conclusion: The ultrasonic findings of metastatic carcinoma in the thyroid gland are various and non-specific. Color Doppler ultrasound may provide ample evidence. The diagnosis depends on FNAC. (authors)

An adjustable multi-scale single beam acoustic tweezers based on ultrahigh frequency ultrasonic transducer.

Science.gov (United States)

Chen, Xiaoyang; Lam, Kwok Ho; Chen, Ruimin; Chen, Zeyu; Yu, Ping; Chen, Zhongping; Shung, K Kirk; Zhou, Qifa

2017-11-01

This paper reports the fabrication, characterization, and microparticle manipulation capability of an adjustable multi-scale single beam acoustic tweezers (SBAT) that is capable of flexibly changing the size of "tweezers" like ordinary metal tweezers with a single-element ultrahigh frequency (UHF) ultrasonic transducer. The measured resonant frequency of the developed transducer at 526 MHz is the highest frequency of piezoelectric single crystal based ultrasonic transducers ever reported. This focused UHF ultrasonic transducer exhibits a wide bandwidth (95.5% at -10 dB) due to high attenuation of high-frequency ultrasound wave, which allows the SBAT effectively excite with a wide range of excitation frequency from 150 to 400 MHz by using the "piezoelectric actuator" model. Through controlling the excitation frequency, the wavelength of ultrasound emitted from the SBAT can be changed to selectively manipulate a single microparticle of different sizes (3-100 μm) by using only one transducer. This concept of flexibly changing "tweezers" size is firstly introduced into the study of SBAT. At the same time, it was found that this incident ultrasound wavelength play an important role in lateral trapping and manipulation for microparticle of different sizes. Biotechnol. Bioeng. 2017;114: 2637-2647. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

A digital, constant-frequency pulsed phase-locked-loop instrument for real-time, absolute ultrasonic phase measurements

Science.gov (United States)

Haldren, H. A.; Perey, D. F.; Yost, W. T.; Cramer, K. E.; Gupta, M. C.

2018-05-01

A digitally controlled instrument for conducting single-frequency and swept-frequency ultrasonic phase measurements has been developed based on a constant-frequency pulsed phase-locked-loop (CFPPLL) design. This instrument uses a pair of direct digital synthesizers to generate an ultrasonically transceived tone-burst and an internal reference wave for phase comparison. Real-time, constant-frequency phase tracking in an interrogated specimen is possible with a resolution of 0.000 38 rad (0.022°), and swept-frequency phase measurements can be obtained. Using phase measurements, an absolute thickness in borosilicate glass is presented to show the instrument's efficacy, and these results are compared to conventional ultrasonic pulse-echo time-of-flight (ToF) measurements. The newly developed instrument predicted the thickness with a mean error of -0.04 μm and a standard deviation of error of 1.35 μm. Additionally, the CFPPLL instrument shows a lower measured phase error in the absence of changing temperature and couplant thickness than high-resolution cross-correlation ToF measurements at a similar signal-to-noise ratio. By showing higher accuracy and precision than conventional pulse-echo ToF measurements and lower phase errors than cross-correlation ToF measurements, the new digitally controlled CFPPLL instrument provides high-resolution absolute ultrasonic velocity or path-length measurements in solids or liquids, as well as tracking of material property changes with high sensitivity. The ability to obtain absolute phase measurements allows for many new applications than possible with previous ultrasonic pulsed phase-locked loop instruments. In addition to improved resolution, swept-frequency phase measurements add useful capability in measuring properties of layered structures, such as bonded joints, or materials which exhibit non-linear frequency-dependent behavior, such as dispersive media.

Speckle Reduction for Ultrasonic Imaging Using Frequency Compounding and Despeckling Filters along with Coded Excitation and Pulse Compression

Directory of Open Access Journals (Sweden)

Joshua S. Ullom

2012-01-01

Full Text Available A method for improving the contrast-to-noise ratio (CNR while maintaining the −6 dB axial resolution of ultrasonic B-mode images is proposed. The technique proposed is known as eREC-FC, which enhances a recently developed REC-FC technique. REC-FC is a combination of the coded excitation technique known as resolution enhancement compression (REC and the speckle-reduction technique frequency compounding (FC. In REC-FC, image CNR is improved but at the expense of a reduction in axial resolution. However, by compounding various REC-FC images made from various subband widths, the tradeoff between axial resolution and CNR enhancement can be extended. Further improvements in CNR can be obtained by applying postprocessing despeckling filters to the eREC-FC B-mode images. The despeckling filters evaluated were the following: median, Lee, homogeneous mask area, geometric, and speckle-reducing anisotropic diffusion (SRAD. Simulations and experimental measurements were conducted with a single-element transducer (f/2.66 having a center frequency of 2.25 MHz and a −3 dB bandwidth of 50%. In simulations and experiments, the eREC-FC technique resulted in the same axial resolution that would be typically observed with conventional excitation with a pulse. Moreover, increases in CNR of 348% were obtained in experiments when comparing eREC-FC with a Lee filter to conventional pulsing methods.

Ultrasonic imaging in concrete

International Nuclear Information System (INIS)

Ribay, G.; Paris, O.; Rambach, J.M.

2009-01-01

The third and final protection barrier confining nuclear reactors is usually a concrete containment structure. Monitoring the structural integrity of these barriers is critical in ensuring the safety of nuclear power plants. The Institute for Radiological Protection and Nuclear Safety (IRSN) in France in collaboration with the French Atomic commission (CEA/LIST) has developed an ultrasonic phased-array technique capable of inspecting thick concrete walls. The non-destructive method is dedicated to detect cracks and bulk defects. Given the thickness of the structure (1.2 m) undergoing inspection and the heterogeneity of the concrete, the optimal frequency lies in the 50-300 kHz range. At these frequencies, the ultrasonic beam profiles are widespread (non-directive) with poor signal-to-noise ratio. Previous studies have shown the potential of using phased-array techniques (i.e., beam focusing and beam steering) in order to improve detection resolution and sizing accuracy. In this paper we present experimental studies performed with array up to 16 transducers working at 200 kHz. Experiments are carried out on representative concrete blocks containing artificial defects. One is a reinforced mock-up representative of the first reinforcing mesh of wall containment. Experimental results show that in spite of the reinforcement, artificial defects deep as half a meter can be detected. Reconstructed images resulting from phased array acquisitions on an artificial crack embedded in a concrete block are also presented and discussed. The presented method allows detecting oriented defects in concrete with improved signal to noise ratio and sensibility. A simulation model of the interaction of ultrasound with a heterogeneous medium like concrete is briefly commented. (authors)

Intravascular ultrasonic-photoacoustic (IVUP) endoscope with 2.2-mm diameter catheter for medical imaging.

Science.gov (United States)

Bui, Nhat Quang; Hlaing, Kyu Kyu; Nguyen, Van Phuc; Nguyen, Trung Hau; Oh, Yun-Ok; Fan, Xiao Feng; Lee, Yong Wook; Nam, Seung Yun; Kang, Hyun Wook; Oh, Junghwan

2015-10-01

Intravascular ultrasound (IVUS) imaging is extremely important for detection and characterization of high-risk atherosclerotic plaques as well as gastrointestinal diseases. Recently, intravascular photoacoustic (IVPA) imaging has been used to differentiate the composition of biological tissues with high optical contrast and ultrasonic resolution. The combination of these imaging techniques could provide morphological information and molecular screening to characterize abnormal tissues, which would help physicians to ensure vital therapeutic value and prognostic significance for patients before commencing therapy. In this study, integration of a high-frequency IVUS imaging catheter (45MHz, single-element, unfocused, 0.7mm in diameter) with a multi-mode optical fiber (0.6mm in core diameter, 0.22 NA), an integrated intravascular ultrasonic-photoacoustic (IVUP) imaging catheter, was developed to provide spatial and functional information on light distribution in a turbid sample. Simultaneously, IVUS imaging was co-registered to IVPA imaging to construct 3D volumetric sample images. In a phantom study, a polyvinyl alcohol (PVA) tissue-mimicking arterial vessel phantom with indocyanine green (ICG) and methylene blue (MB) inclusion was used to demonstrate the feasibility of mapping the biological dyes, which are used in cardiovascular and cancer diagnostics. For the ex vivo study, an excised sample of pig intestine with ICG was utilized to target the biomarkers present in the gastrointestinal tumors or the atherosclerotic plaques with the proposed hybrid technique. The results indicated that IVUP endoscope with the 2.2-mm diameter catheter could be a useful tool for medical imaging. Copyright © 2015 Elsevier Ltd. All rights reserved.

Ultrasonic imaging of material flaws exploiting multipath information

Science.gov (United States)

Shen, Xizhong; Zhang, Yimin D.; Demirli, Ramazan; Amin, Moeness G.

2011-05-01

In this paper, we consider ultrasonic imaging for the visualization of flaws in a material. Ultrasonic imaging is a powerful nondestructive testing (NDT) tool which assesses material conditions via the detection, localization, and classification of flaws inside a structure. Multipath exploitations provide extended virtual array apertures and, in turn, enhance imaging capability beyond the limitation of traditional multisensor approaches. We utilize reflections of ultrasonic signals which occur when encountering different media and interior discontinuities. The waveforms observed at the physical as well as virtual sensors yield additional measurements corresponding to different aspect angles. Exploitation of multipath information addresses unique issues observed in ultrasonic imaging. (1) Utilization of physical and virtual sensors significantly extends the array aperture for image enhancement. (2) Multipath signals extend the angle of view of the narrow beamwidth of the ultrasound transducers, allowing improved visibility and array design flexibility. (3) Ultrasonic signals experience difficulty in penetrating a flaw, thus the aspect angle of the observation is limited unless access to other sides is available. The significant extension of the aperture makes it possible to yield flaw observation from multiple aspect angles. We show that data fusion of physical and virtual sensor data significantly improves the detection and localization performance. The effectiveness of the proposed multipath exploitation approach is demonstrated through experimental studies.

Ultrasonic imaging in LMFBRs using digital techniques

International Nuclear Information System (INIS)

Fothergill, J.R.; McKnight, J.A.; Barrett, L.M.

Ultrasonic technology for providing images of components immersed in the opaque sodium of LMFBRs is being developed at RNL. For many years the application has been restricted by the unavailability of convenient ultrasonic sources and receivers capable of withstanding the reactor environment. Until recently, for example, important ultrasonic instrument design, such as for future sweep arms, had to be based on waveguided ultrasonics. RNL have developed an economic immersible transducer that can be deployed during reactor shut-down, when many demands for ultrasonic imaging are made. The transducer design is not suited at present to the sophisticated techniques of phased arrays; consequently image formation must depend on the physical scanning of a target using one or more transducers in pulse-echo mode. The difficulties of access into a fast reactor impose further restrictions. Some applications may involve easy scanning sequences, thus the sweep arm requires only a rotation to provide a map of the reactor core area. For a more detailed examination of the same area, however, special engineering solutions are needed to provide a more satisfactory scanning sequence. A compromise solution involving the rotating shield movement is being used for a PFR experiment to examine a limited area of the core. (author)

Frontend Receiver Electronics for High Frequency Monolithic CMUT-on-CMOS Imaging Arrays

Science.gov (United States)

Gurun, Gokce; Hasler, Paul; Degertekin, F. Levent

2012-01-01

This paper describes the design of CMOS receiver electronics for monolithic integration with capacitive micromachined ultrasonic transducer (CMUT) arrays for high-frequency intravascular ultrasound imaging. A custom 8-inch wafer is fabricated in a 0.35 μm two-poly, four-metal CMOS process and then CMUT arrays are built on top of the application specific integrated circuits (ASICs) on the wafer. We discuss advantages of the single-chip CMUT-on-CMOS approach in terms of receive sensitivity and SNR. Low-noise and high-gain design of a transimpedance amplifier (TIA) optimized for a forward-looking volumetric-imaging CMUT array element is discussed as a challenging design example. Amplifier gain, bandwidth, dynamic range and power consumption trade-offs are discussed in detail. With minimized parasitics provided by the CMUT-on-CMOS approach, the optimized TIA design achieves a 90 fA/√Hz input referred current noise, which is less than the thermal-mechanical noise of the CMUT element. We show successful system operation with a pulse-echo measurement. Transducer noise-dominated detection in immersion is also demonstrated through output noise spectrum measurement of the integrated system at different CMUT bias voltages. A noise figure of 1.8 dB is obtained in the designed CMUT bandwidth of 10 MHz to 20 MHz. PMID:21859585

Very high cycle fatigue testing of concrete using ultrasonic cycling

Energy Technology Data Exchange (ETDEWEB)

Karr, Ulrike; Schuller, Reinhard; Fitzka, Michael; Mayer, Herwig [Univ. of Natural Resources and Life Sciences, Vienna (Austria). Inst. of Physics and Materials Science; Denk, Andreas; Strauss, Alfred [Univ. of Natural Resources and Life Sciences, Vienna (Austria)

2017-06-01

The ultrasonic fatigue testing method has been further developed to perform cyclic compression tests with concrete. Cylindrical specimens vibrate in resonance at a frequency of approximately 20 kHz with superimposed compressive static loads. The high testing frequency allows time-saving investigations in the very high cycle fatigue regime. Fatigue tests were carried out on ''Concrete 1'' (compressive strength f{sub c} = 80 MPa) and ''Concrete 2'' (f{sub c} = 107 MPa) under purely compressive loading conditions. Experiments at maximum compressive stresses of 0.44 f{sub c} (Concrete 1) and 0.38 f{sub c} (Concrete 2) delivered specimen failures above 109 cycles, indicating that no fatigue limit exists for concrete below one billion load cycles. Resonance frequency, power required to resonate the specimen and second order harmonics of the vibration are used to monitor fatigue damage in situ. Specimens were scanned by X-ray computed tomography prior to and after testing. Fatigue cracks were produced by ultrasonic cycling in the very high cycle fatigue regime at interfaces of grains as well as in cement. The possibilities as well as limitations of ultrasonic fatigue testing of concrete are discussed.

High frequency ultrasound imaging in pupillary block glaucoma.

Science.gov (United States)

Aslanides, I M; Libre, P E; Silverman, R H; Reinstein, D Z; Lazzaro, D R; Rondeau, M J; Harmon, G K; Coleman, D J

1995-01-01

BACKGROUND--The diagnosis of pupillary block glaucoma requires sufficient clarity of the ocular media. This is particularly important for assessment of both the presence and patency of an iridotomy, and the determination of central anterior chamber depth. METHODS--High frequency ultrasonography was used in three patients with suspected pupillary block to determine iris configuration, posterior chamber volume, and ciliary body conformation. RESULTS--All patients demonstrated high frequency ultrasonographic findings consistent with pupillary block: iris bombé, a formed posterior chamber, and a lack of anterior rotation of the ciliary processes. CONCLUSION--High frequency ultrasound imaging appears to be a valuable adjunct in making or corroborating the diagnosis of pupillary block glaucoma. Images PMID:8534666

Ultrasonic characterization of GRC with high percentage of fly ash substitution.

Science.gov (United States)

Genovés, V; Gosálbez, J; Miralles, R; Bonilla, M; Payá, J

2015-07-01

New applications of non-destructive techniques (NDT) with ultrasonic tests (attenuation and velocity by means of ultrasonic frequency sweeps) have been developed for the characterization of fibre-reinforced cementitious composites. According to new lines of research on glass-fibre reinforced cement (GRC) matrix modification, two similar GRC composites with high percentages of fly ash and different water/binder ratios will be studied. Conventional techniques have been used to confirm their low Ca(OH)(2) content (thermogravimetry), fibre integrity (Scanning Electron Microscopy), low porosity (Mercury Intrusion Porosimetry) and good mechanical properties (compression and four points bending test). Ultrasound frequency sweeps allowed the estimation of the attenuation and pulse velocity as functions of frequency. This ultrasonic characterization was correlated successfully with conventional techniques. Copyright © 2015 Elsevier B.V. All rights reserved.

Comparison of morphology and phase composition of hydroxyapatite nanoparticles sonochemically synthesized with dual- or single-frequency ultrasonic reactor

Science.gov (United States)

Deng, Shi-ting; Yu, Hong; Liu, Di; Bi, Yong-guang

2017-10-01

To investigate how a dual- or single-frequency ultrasonic reactor changes the morphology and phase composition of hydroxyapatite nanoparticles (nHAPs), we designed and constructed the preparation of nHAPs using dual- or single-frequency ultrasonic devices, i.e., the single frequency ultrasonic generator with ultrasonic horn (25 kHz), the ultrasonic bath (40 kHz) and the dual-frequency sonochemical systems combined with the ultrasonic horn and the ultrasonic bath simultaneously (25 + 40 kHz). The results showed that the sonicated samples displayed a more uniform shape with less agglomeration than non-sonicated sample. The rod-shaped particles with 1.66 stoichiometry and without a second phase were synthesized successfully in the ultrasonic bath or horn systems. The nHAPs obtained from the dual-frequency ultrasonic systems exhibited a regular rod-shaped structure with better dispersion and more uniform shapes than those of obtained in either ultrasonic bath or horn systems. Additionally, the size of rod-shaped particles obtained in the dual-frequency ultrasound with a mean width of 35 nm and a mean length of 64 nm was smaller than other samples. A possible mechanism is that the dual-frequency ultrasound significantly enhances the cavitation yield over single frequency ultrasound and thus improves the dispersion of particles and reduces the size of the crystals. In addition, irregular holes can be observed in the nanoparticles obtained in the dual-frequency ultrasound. Therefore, the dual-frequency ultrasonic systems are expected to become a convenient, efficient and environmentally friendly synthetic technology to obtain well-defined nHAPs for specific biomedical applications.

Ultrasonic Tomography Imaging for Liquid-Gas Flow Measurement

Directory of Open Access Journals (Sweden)

Muhammad Jaysuman PUSPPANATHAN

2013-01-01

Full Text Available This research was carried out to measure two-phase liquid – gas flow regime by using a dual functionality ultrasonic transducer. Comparing to the common separated transmitter–receiver ultrasonic pairs transducer, the dual functionality ultrasonic transceiver is capable to produce the same measurable results hence further improvises and contributes to the hardware design improvement and system accuracy. Due to the disadvantages and the limitations of the separated ultrasonic transmitter–receiver pair, this paper presents a non-invasive ultrasonic tomography system using ultrasonic transceivers as an alternative approach. Implementation of ultrasonic transceivers, electronic measurement circuits, data acquisition system and suitable image reconstruction algorithms, the measurement of a liquid/gas flow was realized.

A new ultrasonic transducer for improved contrast nonlinear imaging

International Nuclear Information System (INIS)

Bouakaz, Ayache; Cate, Folkert ten; Jong, Nico de

2004-01-01

Second harmonic imaging has provided significant improvement in contrast detection over fundamental imaging. This improvement is a result of a higher contrast-to-tissue ratio (CTR) achievable at the second harmonic frequency. Nevertheless, the differentiation between contrast and tissue at the second harmonic frequency is still in many situations cumbersome and contrast detection remains nowadays as one of the main challenges, especially in the capillaries. The reduced CTR is mainly caused by the generation of second harmonic energy from nonlinear propagation effects in tissue, which hence obscures the echoes from contrast bubbles. In a previous study, we demonstrated theoretically that the CTR increases with the harmonic number. Therefore the purpose of our study was to increase the CTR by selectively looking to the higher harmonic frequencies. In order to be able to receive these high frequency components (third up to the fifth harmonic), a new ultrasonic phased array transducer has been constructed. The main advantage of the new design is its wide frequency bandwidth. The new array transducer contains two different types of elements arranged in an interleaved pattern (odd and even elements). This design enables separate transmission and reception modes. The odd elements operate at 2.8 MHz and 80% bandwidth, whereas the even elements have a centre frequency of 900 kHz with a bandwidth of 50%. The probe is connected to a Vivid 5 system (GE-Vingmed) and proper software is developed for driving. The total bandwidth of such a transducer is estimated to be more than 150% which enables higher harmonic imaging at an adequate sensitivity and signal to noise ratio compared to standard medical array transducers. We describe in this paper the design and fabrication of the array transducer. Moreover its acoustic properties are measured and its performances for nonlinear contrast imaging are evaluated in vitro and in vivo. The preliminary results demonstrate the advantages of

Imaging techniques for ultrasonic testing; Bildgebende Verfahren fuer die Ultraschallpruefung

Energy Technology Data Exchange (ETDEWEB)

NONE

2013-07-01

These seminar proceedings contain 16 lectures on the following topics: 1. From imaging to quantification - ultrasound methods in medical diagnostics; 2. SAFT, TOFD, Phased Array - classical applications and recent developments in ultrasonic imaging; 3. Innovative ultrasonic imaging methods in research and application; 4. Industrial ultrasonic testing of fibre-reinforced structures of complex geometry; 5. Visualisation of crack tips in the inspection of wheel set shafts with longitudinal boreholes as a means of avoiding unnecessary wheel set changes; 6. Areal analysis of the propagation of Lamb waves on curved, anisotropic structures; 7. High-resolution representation in immersion technique testing; 8. Variants in generating images from phased array measurement data - practical examples involving copper, carbon-fibre reinforced plastic and other materials; 9. GIUM - an unconventional method of microstructure imaging using ultrasonic stimulation and laser vibrometry scanning; 10. Innovative air-ultrasonic testing concepts for improved imaging; 11. Use of imaging methods for improving the quality of test results from nondestructive testing; 12. Modelling and visualisation of EMUS stimulation for transducer optimisation; 13. Use of SAFT in the manufacture of energy conversion machines; 14. Ultrasonic imaging tests for improved defect characterisation during weld seam inspection on longitudinally welded large-diameter pipes; 15. SAFT reconstruction for testing austenitic weld seams and dissimilar metal weld seams for transverse cracks; 16. Imaging-based optimisation method for quantitative ultrasonic testing of anisotropic inhomogeneous austenitic welded joints with determination and utilisation of their elastic properties. One contribution has been abstracted separately. [German] Dieser Seminarband enthaelt 16 Vortraege mit folgenden Themen: 1. Von der Bildgebung bis zur Quantifizierung - Ultraschallverfahren in der medizinischen Diagnostik; 2. SAFT, TOFD, Phased Array

Ultrasonic particle image velocimetry for improved flow gradient imaging: algorithms, methodology and validation

International Nuclear Information System (INIS)

Niu Lili; Qian Ming; Yu Wentao; Jin Qiaofeng; Ling Tao; Zheng Hairong; Wan Kun; Gao Shen

2010-01-01

This paper presents a new algorithm for ultrasonic particle image velocimetry (Echo PIV) for improving the flow velocity measurement accuracy and efficiency in regions with high velocity gradients. The conventional Echo PIV algorithm has been modified by incorporating a multiple iterative algorithm, sub-pixel method, filter and interpolation method, and spurious vector elimination algorithm. The new algorithms' performance is assessed by analyzing simulated images with known displacements, and ultrasonic B-mode images of in vitro laminar pipe flow, rotational flow and in vivo rat carotid arterial flow. Results of the simulated images show that the new algorithm produces much smaller bias from the known displacements. For laminar flow, the new algorithm results in 1.1% deviation from the analytically derived value, and 8.8% for the conventional algorithm. The vector quality evaluation for the rotational flow imaging shows that the new algorithm produces better velocity vectors. For in vivo rat carotid arterial flow imaging, the results from the new algorithm deviate 6.6% from the Doppler-measured peak velocities averagely compared to 15% of that from the conventional algorithm. The new Echo PIV algorithm is able to effectively improve the measurement accuracy in imaging flow fields with high velocity gradients.

High-speed biometrics ultrasonic system for 3D fingerprint imaging

Science.gov (United States)

Maev, Roman G.; Severin, Fedar

2012-10-01

The objective of this research is to develop a new robust fingerprint identification technology based upon forming surface-subsurface (under skin) ultrasonic 3D images of the finger pads. The presented work aims to create specialized ultrasonic scanning methods for biometric purposes. Preliminary research has demonstrated the applicability of acoustic microscopy for fingerprint reading. The additional information from internal skin layers and dermis structures contained in the scan can essentially improve confidence in the identification. Advantages of this system include high resolution and quick scanning time. Operating in pulse-echo mode provides spatial resolution up to 0.05 mm. Technology advantages of the proposed technology are the following: • Full-range scanning of the fingerprint area "nail to nail" (2.5 x 2.5 cm) can be done in less than 5 sec with a resolution of up to 1000 dpi. • Collection of information about the in-depth structure of the fingerprint realized by the set of spherically focused 50 MHz acoustic lens provide the resolution ~ 0.05 mm or better • In addition to fingerprints, this technology can identify sweat porous at the surface and under the skin • No sensitivity to the contamination of the finger's surface • Detection of blood velocity using Doppler effect can be implemented to distinguish living specimens • Utilization as polygraph device • Simple connectivity to fingerprint databases obtained with other techniques • The digitally interpolated images can then be enhanced allowing for greater resolution • Method can be applied to fingernails and underlying tissues, providing more information • A laboratory prototype of the biometrics system based on these described principles was designed, built and tested. It is the first step toward a practical implementation of this technique.

Signal-Characteristic analysis with respect to backing material of PVDF-based high-frequency ultrasound for photoacoustic microscopy

Energy Technology Data Exchange (ETDEWEB)

Lee, Jun Su; Chang, Jin Ho [Dept. of Electronic Engineering, Sogang University, Seoul (Korea, Republic of)

2015-04-15

Photoacoustic microscopy is capable of providing high-resolution molecular images, and its spatial resolution is typically determined by ultrasonic transducers used to receive the photoacoustic signals. Therefore, ultrasonic transducers for photoacoustic microscopy (PAM) should have a high operating frequency, broad bandwidth, and high signal-reception efficiency. Polyvinylidene fluoride (PVDF) is a suitable material. To take full advantage of this material, the selection of the backing material is crucial, as it influences the center frequency and bandwidth of the transducer. Therefore, we experimentally determined the most suitable backing material among EPO-TEK 301, E-Solder 3022, and RTV. For this, three PVDF high-frequency single-element transducers were fabricated with each backing material. The center frequency and -6 dB bandwidth of each transducer were ascertained by a pulse-echo test. The spatial resolution of each transducer was examined using wire-target images. The experimental results indicated that EPO-TEK 301 is the most suitable backing material for a PAM transducer. This material provides the highest signal magnitude and a reasonable bandwidth because a large portion of the energy propagates toward the front medium, and the PVDF resonates in the half-wave mode.

21 CFR 892.1550 - Ultrasonic pulsed doppler imaging system.

Science.gov (United States)

2010-04-01

... system. (a) Identification. An ultrasonic pulsed doppler imaging system is a device that combines the... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ultrasonic pulsed doppler imaging system. 892.1550... include signal analysis and display equipment, patient and equipment supports, component parts, and...

Dispersion curve estimation via a spatial covariance method with ultrasonic wavefield imaging.

Science.gov (United States)

Chong, See Yenn; Todd, Michael D

2018-05-01

Numerous Lamb wave dispersion curve estimation methods have been developed to support damage detection and localization strategies in non-destructive evaluation/structural health monitoring (NDE/SHM) applications. In this paper, the covariance matrix is used to extract features from an ultrasonic wavefield imaging (UWI) scan in order to estimate the phase and group velocities of S0 and A0 modes. A laser ultrasonic interrogation method based on a Q-switched laser scanning system was used to interrogate full-field ultrasonic signals in a 2-mm aluminum plate at five different frequencies. These full-field ultrasonic signals were processed in three-dimensional space-time domain. Then, the time-dependent covariance matrices of the UWI were obtained based on the vector variables in Cartesian and polar coordinate spaces for all time samples. A spatial covariance map was constructed to show spatial correlations within the full wavefield. It was observed that the variances may be used as a feature for S0 and A0 mode properties. The phase velocity and the group velocity were found using a variance map and an enveloped variance map, respectively, at five different frequencies. This facilitated the estimation of Lamb wave dispersion curves. The estimated dispersion curves of the S0 and A0 modes showed good agreement with the theoretical dispersion curves. Copyright © 2018 Elsevier B.V. All rights reserved.

A novel high-frequency encoding algorithm for image compression

Science.gov (United States)

Siddeq, Mohammed M.; Rodrigues, Marcos A.

2017-12-01

In this paper, a new method for image compression is proposed whose quality is demonstrated through accurate 3D reconstruction from 2D images. The method is based on the discrete cosine transform (DCT) together with a high-frequency minimization encoding algorithm at compression stage and a new concurrent binary search algorithm at decompression stage. The proposed compression method consists of five main steps: (1) divide the image into blocks and apply DCT to each block; (2) apply a high-frequency minimization method to the AC-coefficients reducing each block by 2/3 resulting in a minimized array; (3) build a look up table of probability data to enable the recovery of the original high frequencies at decompression stage; (4) apply a delta or differential operator to the list of DC-components; and (5) apply arithmetic encoding to the outputs of steps (2) and (4). At decompression stage, the look up table and the concurrent binary search algorithm are used to reconstruct all high-frequency AC-coefficients while the DC-components are decoded by reversing the arithmetic coding. Finally, the inverse DCT recovers the original image. We tested the technique by compressing and decompressing 2D images including images with structured light patterns for 3D reconstruction. The technique is compared with JPEG and JPEG2000 through 2D and 3D RMSE. Results demonstrate that the proposed compression method is perceptually superior to JPEG with equivalent quality to JPEG2000. Concerning 3D surface reconstruction from images, it is demonstrated that the proposed method is superior to both JPEG and JPEG2000.

21 CFR 892.1560 - Ultrasonic pulsed echo imaging system.

Science.gov (United States)

2010-04-01

... system. (a) Identification. An ultrasonic pulsed echo imaging system is a device intended to project a... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Ultrasonic pulsed echo imaging system. 892.1560... receiver. This generic type of device may include signal analysis and display equipment, patient and...

Beat frequency ultrasonic microsphere contrast agent detection system

Science.gov (United States)

Pretlow, III, Robert A. (Inventor); Yost, William T. (Inventor); Cantrell, Jr., John H. (Inventor)

1997-01-01

A system for and method of detecting and measuring concentrations of an ultrasonically-reflective microsphere contrast agent involving detecting non-linear sum and difference beat frequencies produced by the microspheres when two impinging signals with non-identical frequencies are combined by mixing. These beat frequencies can be used for a variety of applications such as detecting the presence of and measuring the flow rates of biological fluids and industrial liquids, including determining the concentration level of microspheres in the myocardium.

An inverse method for crack characterization from ultrasonic B-Scan images

International Nuclear Information System (INIS)

Faur, M.; Roy, O.; Benoist, PH.; Morisseau, PH.

1996-01-01

Concern has been expressed about the capabilities of performing non destructive evaluation (NDE) of flaws located near to the outer surface in nuclear pressurized water reactor (PWR) vessels. The ultrasonic examination of PWR is accomplished from the inside with ultrasonic focused transducers working in the pulse echo mode. By recording the echoes as a function of time, the Ascan representation may be obtained. Many ultrasonic flaw detectors used for NDE are based on the simple Ascan concept involving measuring a time interval called 'time of flight'. By combining the Ascan concept synchronized transducer scanning, one can produce Bscan images that are two dimensional descriptions of the flaw interaction with the ultrasonic field. In the following, the flaw is assumed to be an axially oriented crack (the most serious flaw to be found in a pressurized component). In the case of the outer surface cracks (OSC's), analyzing and interpreting ultrasonic Ascan images become difficult because of the various reflections of the ultrasonic beam on the crack and on the outer surface (the so-called corner effect). Methods for automatic interpretation of ultrasonic experimental data are currently under investigation. In this paper, we present an inverse method for determining the geometrical characteristics of OSC's from ultrasonic Bscan images. The direct model used for the inversion procedure predicts synthetic Bscan images of ultrasonic examination of blocks containing planar defects interrogated by focused probes. (authors)

High temperature ultrasonic transducers for imaging and measurements in a liquid Pb/Bi eutectic alloy.

Science.gov (United States)

Kazys, Rymantas; Voleisis, Algirdas; Sliteris, Reimondas; Mazeika, Liudas; Van Nieuwenhove, Rudi; Kupschus, Peter; Abderrahim, Hamid Aït

2005-04-01

In some nuclear reactors or accelerator-driven systems (ADS) the core is intended to be cooled by means of a heavy liquid metal, for example, lead-bismuth (Pb/Bi) eutectic alloy. For safety and licensing reasons, an imaging method of the interior of ADS, based on application of ultrasonic waves, has thus to be developed. This paper is devoted to description of developed various ultrasonic transducers suitable for long term imaging and measurements in the liquid Pb/Bi alloy. The results of comparative experimental investigations of the developed transducers of different designs in a liquid Pb/Bi alloy up to 450 degrees C are presented. Prototypes with different high temperature piezoelectric materials were investigated: PZT, bismuth titanate (Bi4Ti3O12), lithium niobate (LiNbO3), gallium orthophosphate (GaPO4) and aluminum nitride (A1N). For acoustic coupling with the metal alloy, it was proposed to coat the active surface of the transducers by diamond like carbon (DLC). The radiation robustness was assessed by exposing the transducers to high gamma dose rates in one of the irradiation facilities at SCK x CEN. The experimental results proved that the developed transducers are suitable for long-term operation in harsh conditions.

Ultrasonic Imaging Technology Helps American Manufacturer of Nondestructive Evaluation Equipment Become More Competitive in the Global Market

Science.gov (United States)

1995-01-01

Sonix, Inc., of Springfield, Virginia, has implemented ultrasonic imaging methods developed at the NASA Lewis Research Center. These methods have heretofore been unavailable on commercial ultrasonic imaging systems and provide significantly more sensitive material characterization than conventional high-resolution ultrasonic c-scanning. The technology transfer is being implemented under a cooperative agreement between NASA and Sonix, and several invention disclosures have been submitted by Dr. Roth to protect Lewis interests. Sonix has developed ultrasonic imaging systems used worldwide for microelectronics, materials research, and commercial nondestructive evaluation (NDE). In 1993, Sonix won the U.S. Department of Commerce "Excellence in Exporting" award. Lewis chose to work with Sonix for two main reasons: (1) Sonix is an innovative leader in ultrasonic imaging systems, and (2) Sonix was willing to apply the improvements we developed with our in-house Sonix equipment. This symbiotic joint effort has produced mutual benefits. Sonix recognized the market potential of our new and highly sensitive methods for ultrasonic assessment of material quality. We, in turn, see the cooperative effort as an effective means for transferring our technology while helping to improve the product of a domestic firm.

Measuring the photodetector frequency response for ultrasonic applications by a heterodyne system with difference- frequency servo control.

Science.gov (United States)

Koch, Christian

2010-05-01

A technique for the calibration of photodiodes in ultrasonic measurement systems using standard and cost-effective optical and electronic components is presented. A heterodyne system was realized using two commercially available distributed feedback lasers, and the required frequency stability and resolution were ensured by a difference-frequency servo control scheme. The frequency-sensitive element generating the error signal for the servo loop comprised a delay-line discriminator constructed from electronic elements. Measurements were carried out at up to 450 MHz, and the uncertainties of about 5% (k = 2) can be further reduced by improved radio frequency power measurement without losing the feature of using only simple elements. The technique initially dedicated to the determination of the frequency response of photodetectors applied in ultrasonic applications can be transferred to other application fields of optical measurements.

Structural damage identification based on laser ultrasonic propagation imaging technology

Science.gov (United States)

Chia, Chen-Ciang; Jang, Si-Gwang; Lee, Jung-Ryul; Yoon, Dong-Jin

2009-06-01

An ultrasonic propagation imaging (UPI) system consisted of a Q-switched Nd-YAG pulsed laser and a galvanometer laser mirror scanner was developed. The system which requires neither reference data nor fixed focal length could be used for health monitoring of curved structures. If combined with a fiber acoustic wave PZT (FAWPZT) sensor, it could be used to inspect hot target structures that present formidable challenges to the usage of contact piezoelectric transducers mainly due to the operating temperature limitation of transducers and debonding problem due to the mismatch of coefficient of thermal expansion between the target, transducer and bonding material. The inspection of a stainless steel plate with a curvature radius of about 4 m, having 2mm×1mm open-crack was demonstrated at 150°C using a FAWPZT sensor welded on the plate. Highly-curved surfaces scanning capability and adaptivity of the system for large laser incident angle up to 70° was demonstrated on a stainless steel cylinder with 2mm×1mm open-crack. The imaging results were presented in ultrasonic propagation movie which was a moving wavefield emerged from an installed ultrasonic sensor. Damages were localized by the scattering wavefields. The result images enabled easy detection and interpretation of structural defects as anomalies during ultrasonic wave propagation.

Numeric ultrasonic image processing method: application to non-destructive testing of stainless austenitic steel welds

International Nuclear Information System (INIS)

Corneloup, G.

1988-09-01

A bibliographic research on the means used to improve the ultrasonic inspection of heterogeneous materials such as stainless austenitic steel welds has shown, taking into account the first analysis, a signal assembly in the form of an image (space, time) which carries an original solution to fault detection in highly noisy environments. A numeric grey-level ultrasonic image processing detection method is proposed based on the research of a certain determinism, in the way which the ultrasonic image evolves in space and time in the presence of a defect: the first criterion studies the horizontal stability of the gradients in the image and the second takes into account the time-transient nature of the defect echo. A very important rise in the signal-to-noise ratio obtained in welding inspections evidencing defects (real and artificial) is shown with the help of a computerized ultrasonic image processing/management system, developed for this application [fr

Thumb-size ultrasonic-assisted spectroscopic imager for in-situ glucose monitoring as optional sensor of conventional dialyzers

Science.gov (United States)

Nogo, Kosuke; Mori, Keita; Qi, Wei; Hosono, Satsuki; Kawashima, Natsumi; Nishiyama, Akira; Wada, Kenji; Ishimaru, Ichiro

2016-03-01

We proposed the ultrasonic-assisted spectroscopic imaging for the realization of blood-glucose-level monitoring during dialytic therapy. Optical scattering and absorption caused by blood cells deteriorate the detection accuracy of glucose dissolved in plasma. Ultrasonic standing waves can agglomerate blood cells at nodes. In contrast, around anti-node regions, the amount of transmitted light increases because relatively clear plasma appears due to decline the number of blood cells. Proposed method can disperse the transmitted light of plasma without time-consuming pretreatment such as centrifugation. To realize the thumb-size glucose sensor which can be easily attached to dialysis tubes, an ultrasonic standing wave generator and a spectroscopic imager are required to be small. Ultrasonic oscillators are ∅30[mm]. A drive circuit of oscillators, which now size is 41×55×45[mm], is expected to become small. The trial apparatus of proposed one-shot Fourier spectroscopic imager, whose size is 30×30×48[mm], also can be little-finger size in principal. In the experiment, we separated the suspension mixed water and micro spheres (Θ10[mm) into particles and liquid regions with the ultrasonic standing wave (frequency: 2[MHz]). Furthermore, the spectrum of transmitted light through the suspension could be obtained in visible light regions with a white LED.

Study on Electric field assisted low frequency (20 kHz) ultrasonic spray

Science.gov (United States)

Chae, Ilkyeong; Seong, Baekhoon; Marten, Darmawan; Byun, Doyoung

2015-11-01

Ultrasonic spray is one of the fabulous techniques to discharge small size of droplets because it utilizes ultrasonic vibration on nozzle. However, spray patterns and size of ejected droplet is hardly controlled in conventional ultrasonic spray method. Therefore, here we present electric field assisted ultrasonic spray, which combined conventional technique with electric field in order to control spray pattern and droplet size precisely. Six kinds of various liquid (D.I water, Ethanol, Acetone, Iso-propanol, Toluene, Hexane) with various dielectric constants were used to investigate the mechanism of this method. Also, PIV (Particle Image Velocimetry) was used and various variables were obtained including spray angle, amplitude of liquid vibration, current, and size distribution of ejected droplets. Our electric field assisted ultrasonic spray show that the standard deviation of atomized droplet was decreased up to 39.6%, and it shows the infinite possibility to be utilized in various applications which require precise control of high transfer efficiency. This work was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2014-023284).

Electroless deposition of nickel-boron coatings using low frequency ultrasonic agitation: Effect of ultrasonic frequency on the coatings.

Science.gov (United States)

Bonin, L; Bains, N; Vitry, V; Cobley, A J

2017-05-01

The effect of ultrasound on the properties of Nickel-Boron (NiB) coatings was investigated. NiB coatings were fabricated by electroless deposition using either ultrasonic or mechanical agitation. The deposition of Ni occurred in an aqueous bath containing a reducible metal salt (nickel chloride), reducing agent (sodium borohydride), complexing agent (ethylenediamine) and stabilizer (lead tungstate). Due to the instability of the borohydride in acidic, neutral and slightly alkaline media, pH was controlled at pH 12±1 in order to avoid destabilizing the bath. Deposition was performed in three different configurations: one with a classical mechanical agitation at 300rpm and the other two employing ultrasound at a frequency of either 20 or 35kHz. The microstructures of the electroless coatings were characterized by a combination of optical Microscopy and Scanning Electron Microscope (SEM). The chemistry of the coatings was determined by ICP-AES (Inductively Coupled Plasma - Atomic Emission Spectrometry) after dissolution in aqua regia. The mechanical properties of the coatings were established by a combination of roughness measurements, Vickers microhardness and pin-on-disk tribology tests. Lastly, the corrosion properties were analysed by potentiodynamic polarization. The results showed that low frequency ultrasonic agitation could be used to produce coatings from an alkaline NiB bath and that the thickness of coatings obtained could be increased by over 50% compared to those produced using mechanical agitation. Although ultrasonic agitation produced a smoother coating and some alteration of the deposit morphology was observed, the mechanical and corrosion properties were very similar to those found when using mechanical agitation. Copyright © 2017 Elsevier B.V. All rights reserved.

Graphene-based ultrasonic detector for photoacoustic imaging

Science.gov (United States)

Yang, Fan; Song, Wei; Zhang, Chonglei; Fang, Hui; Min, Changjun; Yuan, Xiaocong

2018-03-01

Taking advantage of optical absorption imaging contrast, photoacoustic imaging technology is able to map the volumetric distribution of the optical absorption properties within biological tissues. Unfortunately, traditional piezoceramics-based transducers used in most photoacoustic imaging setups have inadequate frequency response, resulting in both poor depth resolution and inaccurate quantification of the optical absorption information. Instead of the piezoelectric ultrasonic transducer, we develop a graphene-based optical sensor for detecting photoacoustic pressure. The refractive index in the coupling medium is modulated due to photoacoustic pressure perturbation, which creates the variation of the polarization-sensitive optical absorption property of the graphene. As a result, the photoacoustic detection is realized through recording the reflectance intensity difference of polarization light. The graphene-based detector process an estimated noise-equivalentpressure (NEP) sensitivity of 550 Pa over 20-MHz bandwidth with a nearby linear pressure response from 11.0 kPa to 53.0 kPa. Further, a graphene-based photoacoustic microscopy is built, and non-invasively reveals the microvascular anatomy in mouse ears label-freely.

Ultrasonic imaging with a fixed instrument configuration

Energy Technology Data Exchange (ETDEWEB)

Witten, A.; Tuggle, J.; Waag, R.C.

1988-07-04

Diffraction tomography is a technique based on an inversion of the wave equation which has been proposed for high-resolution ultrasonic imaging. While this approach has been considered for diagnostic medical applications, it has, until recently, been limited by practical limitations on the speed of data acquisition associated with instrument motions. This letter presents the results of an experimental study directed towards demonstrating tomography utilizing a fixed instrument configuration.

A computational modeling approach of the jet-like acoustic streaming and heat generation induced by low frequency high power ultrasonic horn reactors.

Science.gov (United States)

Trujillo, Francisco Javier; Knoerzer, Kai

2011-11-01

High power ultrasound reactors have gained a lot of interest in the food industry given the effects that can arise from ultrasonic-induced cavitation in liquid foods. However, most of the new food processing developments have been based on empirical approaches. Thus, there is a need for mathematical models which help to understand, optimize, and scale up ultrasonic reactors. In this work, a computational fluid dynamics (CFD) model was developed to predict the acoustic streaming and induced heat generated by an ultrasonic horn reactor. In the model it is assumed that the horn tip is a fluid inlet, where a turbulent jet flow is injected into the vessel. The hydrodynamic momentum rate of the incoming jet is assumed to be equal to the total acoustic momentum rate emitted by the acoustic power source. CFD velocity predictions show excellent agreement with the experimental data for power densities higher than W(0)/V ≥ 25kWm(-3). This model successfully describes hydrodynamic fields (streaming) generated by low-frequency-high-power ultrasound. Crown Copyright © 2011. Published by Elsevier B.V. All rights reserved.

Construction of a dog training device with high frequency and high power pulses

International Nuclear Information System (INIS)

Viaud Trejos, Rafael Alfonso

2013-01-01

An electronic device is built to produce high frequency and high power sound. The device is used in training and control of dogs. Commercial ultrasonic devices used for dog training are analyzed. The best strategies and components of the design are determined from an electronic device to produce sounds in frequency from 15kHz to 50Khz. Effectiveness tests are performed to establish the adequate design of the ultrasonic electronic device. The test results are analyzed to find opportunities of improvement in the design or construction of the device [es

Stepped frequency imaging for flaw monitoring: Final report

International Nuclear Information System (INIS)

Hildebrand, B.P.

1988-09-01

This report summarizes the results of research into the usefulness of stepped frequency imaging (SFI) to nuclear power plant inspection. SFI is a method for producing ultrasonic holographic images without the need to sweep a two-dimensional aperture with the transducer. Instead, the transducer may be translated along a line. At each position of the transducer the frequency is stepped over a finite preselected bandwidth. The frequency stepped data is then processed to synthesize the second dimension. In this way it is possible to generate images in regions that are relatively inaccessible to two-dimensional scanners. This report reviews the theory and experimental work verifying the technique, and then explores its possible applications in the nuclear power industry. It also outlines how this new capability can be incorporated into the SDL-1000 Imaging System previously developed for EPRI. The report concludes with five suggestions for uses for the SFI method. These are: monitoring suspect or repaired regions of feedwater nozzles; monitoring pipe cracks repaired by weld overlay; monitoring crack depth during test block production; imaging flaws where access is difficult; and imaging flaws through cladding without distortion

Ultrasound imaging

International Nuclear Information System (INIS)

Wells, P.N.T.

1983-01-01

Ultrasound is a form of energy which consists of mechanical vibrations the frequencies of which are so high that they are above the range of human hearing. The lower frequency limit of the ultrasonic spectrum may generally be taken to be about 20 kHz. Most biomedical applications of ultrasound employ frequencies in the range 1-15 MHz. At these frequencies, the wavelength is in the range 1.5 - 0.1 mm in soft tissues, and narrow beams of ultrasound can be generated which propagate through such tissues without excessive attenuation. This chapter begins with brief reviews of the physics of diagnostic ultrasound pulse-echo imaging methods and Doppler imaging methods. The remainder of the chapter is a resume of the applications of ultrasonic imaging to physiological measurement

An efficient ultrasonic SAFT imaging for pulse-echo immersion testing

International Nuclear Information System (INIS)

Hu, Hong Wei; Jeong, Hyun Jo

2017-01-01

An ultrasonic synthetic aperture focusing technique (SAFT) using a root mean square (RMS) velocity model is proposed for pulse-echo immersion testing to improve the computational efficiency. Considering the immersion ultrasonic testing of a steel block as an example, three kinds of imaging were studied (B-Scan, SAFT imaging based on ray tracing technology and RMS velocity). The experimental results show that two kinds of SAFT imaging have almost the same imaging performance, while the efficiency of RMS velocity SAFT imaging is almost 25 times greater than the SAFT based on Snell's law

An efficient ultrasonic SAFT imaging for pulse-echo immersion testing

Energy Technology Data Exchange (ETDEWEB)

Hu, Hong Wei [Changsha University of Science and Technology, Changsha (China); Jeong, Hyun Jo [Div. of Mechanical and Automotive Engineering, Wonkwang University, Iksan (Korea, Republic of)

2017-04-15

An ultrasonic synthetic aperture focusing technique (SAFT) using a root mean square (RMS) velocity model is proposed for pulse-echo immersion testing to improve the computational efficiency. Considering the immersion ultrasonic testing of a steel block as an example, three kinds of imaging were studied (B-Scan, SAFT imaging based on ray tracing technology and RMS velocity). The experimental results show that two kinds of SAFT imaging have almost the same imaging performance, while the efficiency of RMS velocity SAFT imaging is almost 25 times greater than the SAFT based on Snell's law.

Lead-free piezoelectric materials and ultrasonic transducers for medical imaging

Directory of Open Access Journals (Sweden)

Elaheh Taghaddos

2015-06-01

Full Text Available Piezoelectric materials have been vastly used in ultrasonic transducers for medical imaging. In this paper, firstly, the most promising lead-free compositions with perovskite structure for medical imaging applications have been reviewed. The electromechanical properties of various lead-free ceramics, composites, and single crystals based on barium titanate, bismuth sodium titanate, potassium sodium niobate, and lithium niobate are presented. Then, fundamental principles and design considerations of ultrasonic transducers are briefly described. Finally, recent developments in lead-free ultrasonic probes are discussed and their acoustic performance is compared to lead-based transducers. Focused transducers with different beam focusing methods such as lens focusing and mechanical shaping are explained. Additionally, acoustic characteristics of lead-free probes including the pulse-echo results as well as their imaging capabilities for various applications such as phantom imaging, in vitro intravascular ultrasound imaging of swine aorta, and in vivo or ex vivo imaging of human eyes and skin are reviewed.

Influence of a high vacuum on the precise positioning using an ultrasonic linear motor.

Science.gov (United States)

Kim, Wan-Soo; Lee, Dong-Jin; Lee, Sun-Kyu

2011-01-01

This paper presents an investigation of the ultrasonic linear motor stage for use in a high vacuum environment. The slider table is driven by the hybrid bolt-clamped Langevin-type ultrasonic linear motor, which is excited with its different modes of natural frequencies in both lateral and longitudinal directions. In general, the friction behavior in a vacuum environment becomes different from that in an environment of atmospheric pressure and this difference significantly affects the performance of the ultrasonic linear motor. In this paper, to consistently provide stable and high power of output in a high vacuum, frequency matching was conducted. Moreover, to achieve the fine control performance in the vacuum environment, a modified nominal characteristic trajectory following control method was adopted. Finally, the stage was operated under high vacuum condition, and the operating performances were investigated compared with that of a conventional PI compensator. As a result, robustness of positioning was accomplished in a high vacuum condition with nanometer-level accuracy.

Influence of a high vacuum on the precise positioning using an ultrasonic linear motor

International Nuclear Information System (INIS)

Kim, Wan-Soo; Lee, Dong-Jin; Lee, Sun-Kyu

2011-01-01

This paper presents an investigation of the ultrasonic linear motor stage for use in a high vacuum environment. The slider table is driven by the hybrid bolt-clamped Langevin-type ultrasonic linear motor, which is excited with its different modes of natural frequencies in both lateral and longitudinal directions. In general, the friction behavior in a vacuum environment becomes different from that in an environment of atmospheric pressure and this difference significantly affects the performance of the ultrasonic linear motor. In this paper, to consistently provide stable and high power of output in a high vacuum, frequency matching was conducted. Moreover, to achieve the fine control performance in the vacuum environment, a modified nominal characteristic trajectory following control method was adopted. Finally, the stage was operated under high vacuum condition, and the operating performances were investigated compared with that of a conventional PI compensator. As a result, robustness of positioning was accomplished in a high vacuum condition with nanometer-level accuracy.

Detection and classification of defects in ultrasonic NDE signals using time-frequency representations

Science.gov (United States)

Qidwai, Uvais; Costa, Antonio H.; Chen, C. H.

2000-05-01

The ultrasonic wave, generated by a piezoelectric transducer coupled to the test specimen, propagates through the material and part of its energy is reflected when it encounters an non-homogeneity or discontinuity in its path, while the remainder is reflected by the back surface of the test specimen. Defect echo signals are masked by the characteristics of the measuring instruments, the propagation paths taken by the ultrasonic wave, and are corrupted by additive noise. This leads to difficulties in comparing and analyzing signals, particularly in automated defect identification systems employing different transducers. Further, the multi-component nature of material defects can add to the complexity of the defect identification criteria. With many one-dimensional (1-D) approaches, the multi-component defects can not be detected. Another drawback is that these techniques are not very robust for sharp ultrasonic peaks especially in a very hazardous environment. This paper proposes a technique based on the time-frequency representations (TFRs) of the real defect signals corresponding to artificially produced defects of various geometries in metals. Cohen's class (quadratic) TFRs with Gaussian kernels are then used to represent the signals in the time-frequency (TF) plane. Once the TFR is obtained, various image processing morphological techniques are applied to the TFR (e.g. region of interest masking, edge detection, and profile separation). Based on the results of these operations, a binary image is produced which, in turn, leads to a novel set of features. Using these new features, defects have not only been detected but also classified as flat-cut, angular-cut, and circular-drills. Moreover, with some modifications of the threshold levels of the TFR kernel design, our technique can be used in relatively hostile environments with SNRs as low as 0 dB. Another important characteristic of our approach is the detection of multiple defects. This consists of detection of

Nonlinear ultrasonic imaging with X wave

Science.gov (United States)

Du, Hongwei; Lu, Wei; Feng, Huanqing

2009-10-01

X wave has a large depth of field and may have important application in ultrasonic imaging to provide high frame rate (HFR). However, the HFR system suffers from lower spatial resolution. In this paper, a study of nonlinear imaging with X wave is presented to improve the resolution. A theoretical description of realizable nonlinear X wave is reported. The nonlinear field is simulated by solving the KZK nonlinear wave equation with a time-domain difference method. The results show that the second harmonic field of X wave has narrower mainlobe and lower sidelobes than the fundamental field. In order to evaluate the imaging effect with X wave, an imaging model involving numerical calculation of the KZK equation, Rayleigh-Sommerfeld integral, band-pass filtering and envelope detection is constructed to obtain 2D fundamental and second harmonic images of scatters in tissue-like medium. The results indicate that if X wave is used, the harmonic image has higher spatial resolution throughout the entire imaging region than the fundamental image, but higher sidelobes occur as compared to conventional focus imaging. A HFR imaging method with higher spatial resolution is thus feasible provided an apodization method is used to suppress sidelobes.

Ultrasonic signal processing and B-SCAN imaging for nondestructive testing. Application to under - cladding - cracks

International Nuclear Information System (INIS)

Theron, G.

1988-02-01

Crack propagation under the stainless steel cladding of nuclear reactor vessels is monitored by ultrasonic testing. This work study signal processing to improve detection and sizing of defects. Two possibilities are examined: processing of each individual signal and simultaneous processing of all the signals giving a B-SCAN image. The bibliographic study of time-frequency methods shows that they are not suitable for pulses. Then decomposition in instantaneous frequency and envelope is used. Effect of interference of 2 close echoes on instantaneous frequency is studies. The deconvolution of B-SCAN images is obtained by the transducer field. A point-by-point deconvolution method, less noise sensitive, is developed. B-SCAN images are processed in 2 phases: interface signal processing and deconvolution. These calculations improve image accuracy and dynamics. Water-stell interface and ferritic-austenitic interface are separated. Echoes of crack top are visualized and crack-hole differentiation is improved [fr

Ultrasonic off-normal imaging techniques for under sodium viewing

International Nuclear Information System (INIS)

Michaels, T.E.; Horn, J.E.

1979-01-01

Advanced imaging methods have been evaluated for the purpose of constructing images of objects from ultrasonic data. Feasibility of imaging surfaces which are off-normal to the sound beam has been established. Laboratory results are presented which show a complete image of a typical core component. Using the previous system developed for under sodium viewing (USV), only normal surfaces of this object could be imaged. Using advanced methods, surfaces up to 60 degrees off-normal have been imaged. Details of equipment and procedures used for this image construction are described. Additional work on high temperature transducers, electronics, and signal analysis is required in order to adapt the off-normal viewing process described here to an eventual USV application

Remote diagnosis via a telecommunication satellite--ultrasonic tomographic image transmission experiments.

Science.gov (United States)

Nakajima, I; Inokuchi, S; Tajima, T; Takahashi, T

1985-04-01

An experiment to transmit ultrasonic tomographic section images required for remote medical diagnosis and care was conducted using the mobile telecommunication satellite OSCAR-10. The images received showed the intestinal condition of a patient incapable of verbal communication, however the image screen had a fairly coarse particle structure. On the basis of these experiments, were considered as the transmission of ultrasonic tomographic images extremely effective in remote diagnosis.

Ultrasonic image analysis and image-guided interventions.

Science.gov (United States)

Noble, J Alison; Navab, Nassir; Becher, H

2011-08-06

The fields of medical image analysis and computer-aided interventions deal with reducing the large volume of digital images (X-ray, computed tomography, magnetic resonance imaging (MRI), positron emission tomography and ultrasound (US)) to more meaningful clinical information using software algorithms. US is a core imaging modality employed in these areas, both in its own right and used in conjunction with the other imaging modalities. It is receiving increased interest owing to the recent introduction of three-dimensional US, significant improvements in US image quality, and better understanding of how to design algorithms which exploit the unique strengths and properties of this real-time imaging modality. This article reviews the current state of art in US image analysis and its application in image-guided interventions. The article concludes by giving a perspective from clinical cardiology which is one of the most advanced areas of clinical application of US image analysis and describing some probable future trends in this important area of ultrasonic imaging research.

The parallel-sequential field subtraction technique for coherent nonlinear ultrasonic imaging

Science.gov (United States)

Cheng, Jingwei; Potter, Jack N.; Drinkwater, Bruce W.

2018-06-01

Nonlinear imaging techniques have recently emerged which have the potential to detect cracks at a much earlier stage than was previously possible and have sensitivity to partially closed defects. This study explores a coherent imaging technique based on the subtraction of two modes of focusing: parallel, in which the elements are fired together with a delay law and sequential, in which elements are fired independently. In the parallel focusing a high intensity ultrasonic beam is formed in the specimen at the focal point. However, in sequential focusing only low intensity signals from individual elements enter the sample and the full matrix of transmit-receive signals is recorded and post-processed to form an image. Under linear elastic assumptions, both parallel and sequential images are expected to be identical. Here we measure the difference between these images and use this to characterise the nonlinearity of small closed fatigue cracks. In particular we monitor the change in relative phase and amplitude at the fundamental frequencies for each focal point and use this nonlinear coherent imaging metric to form images of the spatial distribution of nonlinearity. The results suggest the subtracted image can suppress linear features (e.g. back wall or large scatters) effectively when instrumentation noise compensation in applied, thereby allowing damage to be detected at an early stage (c. 15% of fatigue life) and reliably quantified in later fatigue life.

Inspection of copper canisters for spent nuclear fuel by means of ultrasound. Ultrasonic imaging of EB weld, theory of harmonic imaging of welds, NDE of cast iron

International Nuclear Information System (INIS)

Stepinski, T.; Lingvall, F.; Ping Wu

2001-07-01

presented. The calculated results show how the harmonics evolve as the plane wave propagates. It should be noted that the work presented here is at its preliminary stage, the goal of the present and future work is to build a simulating tool for material harmonic imaging technology. The theory of phase conjugation is presented and different methods of wave phase conjugation (WPC) are reviewed and characterized in the third chapter. The ability of WPC to self-adaptive focus ultrasonic waves in inhomogeneous media makes it interesting in the application to the inspection of as EB welds. The WPC can be performed either in time or frequency domain. Time domain method, known as time reversal mirrors is reviewed in some detail with focus on its applications to NDT. Frequency domain techniques use nonlinear piezoelectric or magnetic materials. The choice of magneto-acoustic phase conjugation, performed in nonlinear magnetic ceramics as a candidate for the feasibility demonstration is motivated. Details of the preliminary experiment with high frequency NDE application (10 MHz) are presented. NDE methods suitable for the characterization of cast iron are reviewed in the fourth chapter. Two groups of methods that could be used in an industrial environment, those based on ultrasound and on eddy current measurement are presented in some detail. The review is focused on sensing the interaction of elastic waves with the microstructure of cast iron. It is explained how three different features of ultrasound, the sound velocity, the attenuation and the backscattering, can be used for the characterization

Inspection of copper canisters for spent nuclear fuel by means of ultrasound. Ultrasonic imaging of EB weld, theory of harmonic imaging of welds, NDE of cast iron

Energy Technology Data Exchange (ETDEWEB)

Stepinski, T.; Lingvall, F.; Ping Wu [Uppsala Univ. (Sweden). Dept. of Materials Science

2001-07-01

presented. The calculated results show how the harmonics evolve as the plane wave propagates. It should be noted that the work presented here is at its preliminary stage, the goal of the present and future work is to build a simulating tool for material harmonic imaging technology. The theory of phase conjugation is presented and different methods of wave phase conjugation (WPC) are reviewed and characterized in the third chapter. The ability of WPC to self-adaptive focus ultrasonic waves in inhomogeneous media makes it interesting in the application to the inspection of as EB welds. The WPC can be performed either in time or frequency domain. Time domain method, known as time reversal mirrors is reviewed in some detail with focus on its applications to NDT. Frequency domain techniques use nonlinear piezoelectric or magnetic materials. The choice of magneto-acoustic phase conjugation, performed in nonlinear magnetic ceramics as a candidate for the feasibility demonstration is motivated. Details of the preliminary experiment with high frequency NDE application (10 MHz) are presented. NDE methods suitable for the characterization of cast iron are reviewed in the fourth chapter. Two groups of methods that could be used in an industrial environment, those based on ultrasound and on eddy current measurement are presented in some detail. The review is focused on sensing the interaction of elastic waves with the microstructure of cast iron. It is explained how three different features of ultrasound, the sound velocity, the attenuation and the backscattering, can be used for the characterization.

ULTRASONIC ASSEMBLY [REVIEW

Directory of Open Access Journals (Sweden)

PORAV Viorica

2015-05-01

Full Text Available The paper exposes the possibility of machine producesers to optimize the costs of clothes assembling. Ultrasonic systems being frequently utilized have many advantages on semi products of synthetic textile and technical textile. First of all, sewing – cutting process can be accomplished under high speeds and rate of losses can be minimized. Cutting seal applications are frequently used for underwear and sportswear. Slicing and unit cutting machines, as well as portable sealing machines are available for labeling sector. Products such as bag, pocket and cover can be sewed in a seamless manner for promotion purposes. All objects in terms of accessories are obtained in same standard. Our quilting machines are preferred in worldwide due to its threadless, high quality sealing. An alternative to the classic sewing assembly, with thread and needles is ultrasonic seaming. In ultrasonic welding, there are no connective bolts, nails, soldering materials, or adhesives necessary to bind the materials together. Ultrasonic is defined as acoustic frequencies above the range audible to the human ear. Ultrasonic frequencies are administered to the fabric from the sonotrode of bonding machine. The high frequency and powerful energy produced, when is release in one special environment, the ultrasound heating this environment. The ability to ultrasonic weld textiles and films depend on their thermoplastic contents and the desired end results. The paper defines the weld ability of more common textiles and films. The welding refers to all types of bonding and sealing, as in point bonding of fabric, or continuous sealing of film.

Image processing applied to automatic detection of defects during ultrasonic examination

International Nuclear Information System (INIS)

Moysan, J.

1992-10-01

This work is a study about image processing applied to ultrasonic BSCAN images which are obtained in the field of non destructive testing of weld. The goal is to define what image processing techniques can bring to ameliorate the exploitation of the data collected and, more precisely, what image processing can do to extract the meaningful echoes which enable to characterize and to size the defects. The report presents non destructive testing by ultrasounds in the nuclear field and it indicates specificities of the propagation of ultrasonic waves in austenitic weld. It gives a state of the art of the data processing applied to ultrasonic images in nondestructive evaluation. A new image analysis is then developed. It is based on a powerful tool, the co-occurrence matrix. This matrix enables to represent, in a whole representation, relations between amplitudes of couples of pixels. From the matrix analysis, a new complete and automatic method has been set down in order to define a threshold which separates echoes from noise. An automatic interpretation of the ultrasonic echoes is then possible. Complete validation has been done with standard pieces

Generating porosity spectrum of carbonate reservoirs using ultrasonic imaging log

Science.gov (United States)

Zhang, Jie; Nie, Xin; Xiao, Suyun; Zhang, Chong; Zhang, Chaomo; Zhang, Zhansong

2018-03-01

Imaging logging tools can provide us the borehole wall image. The micro-resistivity imaging logging has been used to obtain borehole porosity spectrum. However, the resistivity imaging logging cannot cover the whole borehole wall. In this paper, we propose a method to calculate the porosity spectrum using ultrasonic imaging logging data. Based on the amplitude attenuation equation, we analyze the factors affecting the propagation of wave in drilling fluid and formation and based on the bulk-volume rock model, Wyllie equation and Raymer equation, we establish various conversion models between the reflection coefficient β and porosity ϕ. Then we use the ultrasonic imaging logging and conventional wireline logging data to calculate the near-borehole formation porosity distribution spectrum. The porosity spectrum result obtained from ultrasonic imaging data is compared with the one from the micro-resistivity imaging data, and they turn out to be similar, but with discrepancy, which is caused by the borehole coverage and data input difference. We separate the porosity types by performing threshold value segmentation and generate porosity-depth distribution curves by counting with equal depth spacing on the porosity image. The practice result is good and reveals the efficiency of our method.

Ultrasonic two-dimensional imaging of the heart with multiscan

International Nuclear Information System (INIS)

Roelandt, J.R.T.C.

1980-01-01

The aim of the author was to present the implementation into cardiology of the ultrasonic linear array scanner. The first clinical results, the progress in examination technique and potential applications are described. One method which complements the ultrasonic imaging capabilities is the use of the echo contrast. (Auth.)

High-resolution wave-theory-based ultrasound reflection imaging using the split-step fourier and globally optimized fourier finite-difference methods

Science.gov (United States)

Huang, Lianjie

2013-10-29

Methods for enhancing ultrasonic reflection imaging are taught utilizing a split-step Fourier propagator in which the reconstruction is based on recursive inward continuation of ultrasonic wavefields in the frequency-space and frequency-wave number 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-wave number 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 tissue being imaged (e.g., breast tissue). Results from various data input to the method indicate significant improvements are provided in both image quality and resolution.

Small scale imaging using ultrasonic tomography

International Nuclear Information System (INIS)

Zakaria, Z.; Abdul Rahim, R.; Megat Ali, M.S.A.; Baharuddin, M.Y.; Jahidin, A.H.

2009-01-01

Ultrasound technology progressed through the 1960 from simple A-mode and B-mode scans to today M-mode and Doppler two dimensional (2-D) and even three dimensional (3-D) systems. Modern ultrasound imaging has its roots in sonar technology after it was first described by Lord John Rayleigh over 100 years ago on the interaction of acoustic waves with media. Tomography technique was developed as a diagnostic tool in the medical area since the early of 1970s. This research initially focused on how to retrieve a cross sectional images from living and non-living things. After a decade, the application of tomography systems span into the industrial area. However, the long exposure time of medical radiation-based method cannot tolerate the dynamic changes in industrial process two phase liquid/ gas flow system. An alternative system such as a process tomography systems, can give information on the nature of the flow regime characteristic. The overall aim of this paper is to investigate the use of a small scale ultrasonic tomography method based on ultrasonic transmission mode tomography for online monitoring of liquid/ gas flow in pipe/ vessel system through ultrasonic transceivers application. This non-invasive technique applied sixteen transceivers as the sensing elements to cover the pipe/ vessel cross section. The paper also details the transceivers selection criteria, hardware setup, the electronic measurement circuit and also the image reconstruction algorithm applied. The system was found capable of visualizing the internal characteristics and provides the concentration profile for the corresponding liquid and gas phases. (author)

Methanolysis of triolein by low frequency ultrasonic irradiation

Energy Technology Data Exchange (ETDEWEB)

Hanh, Hoang Duc; Starvarache, Carmen; Okitsu, Kenji; Maeda, Yasuaki; Nishimura, Rokuro [Graduate School of Engineering, Osaka Prefecture University, Gakuen-cho 1-1, Sakai, Osaka 599-8531 (Japan); Dong, Nguyen The [Institute of Environmental Technology, Vietnamese Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi (Viet Nam)

2008-02-15

Methanolysis of triolein was investigated at room temperature by 40 kHz ultrasonic irradiation to make biodiesel fuel as methyl esters. It was found that the yield of methyl esters strongly depended on the amount of KOH and the molar ratio of methanol to triolein (M/T) and was highest at the M/T molar ratio of 6/1, KOH concentration of 1 wt% and irradiation time of 30 min. In addition, the effects of sonication on the methanolysis of triolein were discussed in comparison to the effects of stirring experiments. The optimum condition under stirring experiments showed that the molar ratio of M/T, KOH concentration and reaction time were 6/1, 1.5 wt% and 4 h, respectively. These results clearly indicated that the ultrasonic irradiation method would be a promising one compared to the conventional stirring method. The high yield under the ultrasonic irradiation condition would be due to high speed mixing and mass transfer between the methanol and triolein as well as the formation of a microemulsion resulting from the ultrasonic cavitation phenomenon. (author)

Methanolysis of triolein by low frequency ultrasonic irradiation

Energy Technology Data Exchange (ETDEWEB)

Hoang Duc Hanh [Graduate School of Engineering, Osaka Prefecture University, Gakuen-cho 1-1, Sakai, Osaka 599-8531 (Japan)], E-mail: hoangduchanh75@yahoo.com; Nguyen The Dong [Institute of Environmental Technology, Vietnamese Academy of Science and Technology, 18 Hoang Quoc Viet, Cau Giay, Hanoi (Viet Nam); Starvarache, Carmen; Okitsu, Kenji; Maeda, Yasuaki; Nishimura, Rokuro [Graduate School of Engineering, Osaka Prefecture University, Gakuen-cho 1-1, Sakai, Osaka 599-8531 (Japan)

2008-02-15

Methanolysis of triolein was investigated at room temperature by 40 kHz ultrasonic irradiation to make biodiesel fuel as methyl esters. It was found that the yield of methyl esters strongly depended on the amount of KOH and the molar ratio of methanol to triolein (M/T) and was highest at the M/T molar ratio of 6/1, KOH concentration of 1 wt% and irradiation time of 30 min. In addition, the effects of sonication on the methanolysis of triolein were discussed in comparison to the effects of stirring experiments. The optimum condition under stirring experiments showed that the molar ratio of M/T, KOH concentration and reaction time were 6/1, 1.5 wt% and 4 h, respectively. These results clearly indicated that the ultrasonic irradiation method would be a promising one compared to the conventional stirring method. The high yield under the ultrasonic irradiation condition would be due to high speed mixing and mass transfer between the methanol and triolein as well as the formation of a microemulsion resulting from the ultrasonic cavitation phenomenon.

Inactivation of Enterobacter aerogenes in reconstituted skim milk by high- and low-frequency ultrasound.

Science.gov (United States)

Gao, Shengpu; Hemar, Yacine; Lewis, Gillian D; Ashokkumar, Muthupandian

2014-11-01

The inactivation of Enterobacter aerogenes in skim milk using low-frequency (20kHz) and high-frequency (850kHz) ultrasonication was investigated. It was found that low-frequency acoustic cavitation resulted in lethal damage to E. aerogenes. The bacteria were more sensitive to ultrasound in water than in reconstituted skim milk having different protein concentrations. However, high-frequency ultrasound was not able to inactivate E. aerogenes in milk even when powers as high as 50W for 60min were used. This study also showed that high-frequency ultrasonication had no influence on the viscosity and particle size of skim milk, whereas low-frequency ultrasonication resulted in the decrease in viscosity and particle size of milk. The decrease in particle size is believed to be due to the breakup of the fat globules, and possibly to the cleavage of the κ-casein present at the surface of the casein micelles. Whey proteins were also found to be slightly affected by low-frequency ultrasound, with the amounts of α-lactalbumin and β-lactoglobulin slightly decreasing. Copyright © 2013. Published by Elsevier B.V.

Variable-Frequency Ultrasonic Treatment on Microstructure and Mechanical Properties of ZK60 Alloy during Large Diameter Semi-Continuous Casting

Directory of Open Access Journals (Sweden)

Xingrui Chen

2017-05-01

Full Text Available Traditional fixed-frequency ultrasonic technology and a variable-frequency ultrasonic technology were applied to refine the as-cast microstructure and improve the mechanical properties of a ZK60 (Mg–Zn–Zr alloy during large diameter semi-continuous casting. The acoustic field propagation was obtained by numerical simulation. The microstructure of the as-cast samples was characterized by optical and scanning electron microscopy. The variable-frequency ultrasonic technology shows its outstanding ability in grain refinement compared with traditional fixed-ultrasonic technology. The variable-frequency acoustic field promoted the formation of small α-Mg globular grains and changed the distribution and morphology of β-phases throughout the castings. Ultimate tensile strength and elongation are increased to 280 MPa and 8.9%, respectively, which are 19.1% and 45.9% higher than the values obtained from billets without ultrasonic treatment and are 11.6% and 18.7% higher than fixed-frequency ultrasound treated billets. Different refinement efficiencies appear in different districts of billets attributed to the sound attenuation in melt. The variable-frequency acoustic field improves the refinement effect by enhancing cavitation-enhanced heterogeneous nucleation and dendrite fragmentation effects.

Energetic balance in an ultrasonic reactor using focused or flat high frequency transducers.

Science.gov (United States)

Hallez, L; Touyeras, F; Hihn, J Y; Klima, J

2007-09-01

In order to undertake irradiation of polymer blocks or films by ultrasound, this paper deals with the measurements of ultrasonic power and its distribution within the cell by several methods. The electric power measured at the transducer input is compared to the ultrasonic power input to the cell evaluated by calorimetry and radiation force measurement for different generator settings. Results obtained in the specific case of new transducer types (composites and focused composites i.e., HIFU: high intensity focused ultrasound) provide an opportunity to conduct a discussion about measurement methods. It has thus been confirmed that these measurement techniques can be applied to HIFU transducers. For all cases, results underlined the fact that measurement of radiation pressure for power evaluation is more adapted to low powers (generator-transducer-liquid and sample.

Ultrasonic inspection

International Nuclear Information System (INIS)

Satittada, Gannaga

1984-01-01

Ultrasonic inspection is one of the most widely used methods for nondestructive inspection. The beam of high-frequency sound wave, ultrasonic wave, is introduced into the material. It travels through the material with some attendant loss of energy and can be reflected at interfaces. The reflected beam is detected and analyzed. Ultrasonic inspection is used to detect flaws in metal parts as well as in welded, brazed and bonded joints during research work and developing production and service. It is also used to detect and locate porosity, pipe, and flakes. In addition, it can be used for the measurement of metal thickness. Ultrasonic inspection is therefore used for quality control and material inspection in all major industries

Ultrasonic imaging in liquid sodium

Energy Technology Data Exchange (ETDEWEB)

Lubeigt, E. [CEA Cadarache, DEN/DTN/STCP/LIET, 13108 Saint-Paul-Lez-Durance Cedex (France); Laboratoire de Mecanique et d' Acoustique, CNRS UPR 7051, 13402 Marseille Cedex 20 (France); Mensah, S.; Chaix, J.F.; Rakotonarivo, S. [Laboratoire de Mecanique et d' Acoustique, CNRS UPR 7051, 13402 Marseille Cedex 20 (France); Gobillot, G. [CEA Cadarache, DEN/DTN/STCP/LIET, 13108 Saint-Paul-Lez-Durance Cedex (France)

2015-07-01

The fourth generation of nuclear reactor can use liquid sodium as the core coolant. When the reactor is operating, sodium temperatures can reach up to 600 deg. C. During maintenance periods, when the reactor is shut down, the coolant temperature is reduced to 200 deg. C. Because molten sodium is optically opaque, ultrasonic imaging techniques are developed for maintenance activities. Under-sodium imaging aims at i) checking the health of immersed structures. It should also allow ii) to assess component degradation or damage as cracks and shape defects as well as iii) the detection of lost objects. The under-sodium imaging system has to sustain high temperature (up to 300 deg. C) and hostility of the sodium environment. Furthermore, specific constraints such as transducers characteristics or the limited sensor mobility in the reactor vessel have to be considered. This work focuses on developing a methodology for detecting damages such as crack defects with ultrasound devices. Surface-breaking cracks or deep cracks are sought in the weld area, as welds are more subject to defects. Traditional methods enabled us to detect emerging cracks of submillimeter size with sodium-compatible high-temperature transducer. The presented approach relies on making use of prior knowledge about the environment through the implementation of differential imaging and time-reversal techniques. Indeed, this approach allows to detect a change by comparison with a reference measurement and by focusing back to any change in the environment. It is a means of analysis and understanding of the physical phenomena making it possible to design more effective inspection strategies. Difference between the measured signals reveals the acoustic field scattered by a perturbation (a crack for instance), which may occur between periodical measurements. The imaging method relies on the adequate combination of two computed ultrasonic fields, one forward and one adjoint. The adjoint field, which carries the

Ultrasonic imaging in liquid sodium

International Nuclear Information System (INIS)

Lubeigt, E.; Mensah, S.; Chaix, J.F.; Rakotonarivo, S.; Gobillot, G.

2015-01-01

The fourth generation of nuclear reactor can use liquid sodium as the core coolant. When the reactor is operating, sodium temperatures can reach up to 600 deg. C. During maintenance periods, when the reactor is shut down, the coolant temperature is reduced to 200 deg. C. Because molten sodium is optically opaque, ultrasonic imaging techniques are developed for maintenance activities. Under-sodium imaging aims at i) checking the health of immersed structures. It should also allow ii) to assess component degradation or damage as cracks and shape defects as well as iii) the detection of lost objects. The under-sodium imaging system has to sustain high temperature (up to 300 deg. C) and hostility of the sodium environment. Furthermore, specific constraints such as transducers characteristics or the limited sensor mobility in the reactor vessel have to be considered. This work focuses on developing a methodology for detecting damages such as crack defects with ultrasound devices. Surface-breaking cracks or deep cracks are sought in the weld area, as welds are more subject to defects. Traditional methods enabled us to detect emerging cracks of submillimeter size with sodium-compatible high-temperature transducer. The presented approach relies on making use of prior knowledge about the environment through the implementation of differential imaging and time-reversal techniques. Indeed, this approach allows to detect a change by comparison with a reference measurement and by focusing back to any change in the environment. It is a means of analysis and understanding of the physical phenomena making it possible to design more effective inspection strategies. Difference between the measured signals reveals the acoustic field scattered by a perturbation (a crack for instance), which may occur between periodical measurements. The imaging method relies on the adequate combination of two computed ultrasonic fields, one forward and one adjoint. The adjoint field, which carries the

Measurement of flaw size in a weld sample by ultrasonic frequency analysis

International Nuclear Information System (INIS)

Whaley, H.L. Jr.; Adler, L.; Cook, K.V.; McClung, R.W.

1975-05-01

An ultrasonic frequency analysis technique has been developed and applied to the measurement of flaws in an 8-in.-thick heavy-section steel specimen belonging to the Pressure Vessel Research Committee program. Using the technique the flaws occurring in the weld area were characterized in quantitative terms of both dimension and orientation. Several modifications of the technique were made during the study to include the application of several transducers and to consider ultrasonic mode conversion. (U.S.)

Simulation and fabrication of 0-3 composite PZT films for ultrahigh frequency (100-300 MHz) ultrasonic transducers

Science.gov (United States)

Chen, Xiaoyang; Fei, Chunlong; Chen, Zeyu; Chen, Ruimin; Yu, Ping; Chen, Zhongping; Shung, K. Kirk; Zhou, Qifa

2016-03-01

This paper presents simulation, fabrication, and characterization of single-element ultrahigh frequency (100-300-MHz) needle ultrasonic transducers based on 0-3 composite Pb(Zr0.52Ti0.48)O3 (PZT) films prepared by using composite ceramic sol-gel film and sol-infiltration technique. The center frequency of the developed transducer at 300-MHz was the highest frequency of PbTiO3 ceramic-based ultrasonic transducers ever reported. Furthermore, a brief description of the composite model was followed by the development of a new expression for predicting the longitudinal velocity, the clamped dielectric constant, and the complex electromechanical coupling coefficient kt of these films, which is very important in ultrasonic transducer design. Moreover, these parameters are difficult to obtain by measuring the frequency dependence of impedance and phase angle because of the weak signal of the previous 0-3 composite films transducer (>100 MHz). The modeling results show that the Cubes model with a geometric factor n = 0.05 fits well with the measured data. This model will be helpful for developing the 0-3 composite systems for ultrahigh frequency ultrasonic transducer design.

New method to enhance the extraction yield of rutin from Sophora japonica using a novel ultrasonic extraction system by determining optimum ultrasonic frequency.

Science.gov (United States)

Liao, Jianqing; Qu, Baida; Liu, Da; Zheng, Naiqin

2015-11-01

A new method has been proposed for enhancing extraction yield of rutin from Sophora japonica, in which a novel ultrasonic extraction system has been developed to perform the determination of optimum ultrasonic frequency by a two-step procedure. This study has systematically investigated the influence of a continuous frequency range of 20-92 kHz on rutin yields. The effects of different operating conditions on rutin yields have also been studied in detail such as solvent concentration, solvent to solid ratio, ultrasound power, temperature and particle size. A higher extraction yield was obtained at the ultrasonic frequency of 60-62 kHz which was little affected under other extraction conditions. Comparative studies between existing methods and the present method were done to verify the effectiveness of this method. Results indicated that the new extraction method gave a higher extraction yield compared with existing ultrasound-assisted extraction (UAE) and soxhlet extraction (SE). Thus, the potential use of this method may be promising for extraction of natural materials on an industrial scale in the future. Copyright © 2015 Elsevier B.V. All rights reserved.

The influence of ultrasonic waves on molecular structure of high impact polystyrene solutions in different solvents

International Nuclear Information System (INIS)

Al-Asaly, S.I.

1991-01-01

The aim of the this research is to study some physical properties of polymer solutions of high-impact polystyrene (HIPS) solutions in two different solvents (carbon tetrachloride, xylene) by using ultrasonic technique. Absorption coefficient and velocity of ultrasonic waves through different concentrations of these solutions were measured using ultrasonic pulsed generator at constant frequency (800) KHz. The result implies that there is no chemical interaction between (HIPS) molecules and the solvents. 5 tabs.; 18 figs.; 59 refs

High-speed monodisperse droplet generation by ultrasonically controlled micro-jet breakup

Science.gov (United States)

Frommhold, Philipp Erhard; Lippert, Alexander; Holsteyns, Frank Ludwig; Mettin, Robert

2014-04-01

A liquid jet that is ejected from a nozzle into air will disintegrate into drops via the well-known Plateau-Rayleigh instability within a certain range of Ohnesorge and Reynolds numbers. With the focus on the micrometer scale, we investigate the control of this process by superimposing a suitable ultrasonic signal, which causes the jet to break up into a very precise train of monodisperse droplets. The jet leaves a pressurized container of liquid via a small orifice of about 20 μm diameter. The break-up process and the emerging droplets are recorded via high-speed imaging. An extended parameter study of exit speed and ultrasonic frequency is carried out for deionized water to evaluate the jet's state and the subsequent generation of monodisperse droplets. Maximum exit velocities obtained reach almost 120 m s-1, and frequencies have been applied up to 1.8 MHz. Functionality of the method is confirmed for five additional liquids for moderate jet velocities 38 m s-1. For the uncontrolled jet disintegration, the drop size spectra revealed broad distributions and downstream drop growth by collision, while the acoustic control generated monodisperse droplets with a standard deviation less than 0.5 %. By adjustment of the acoustic excitation frequency, drop diameters could be tuned continuously from about 30 to 50 μm for all exit speeds. Good agreement to former experiments and theoretical approaches is found for the relation of overpressure and jet exit speed, and for the observed stability regions of monodisperse droplet generation in the parameter plane of jet speed and acoustic excitation frequency. Fitting of two free parameters of the general theory to the liquids and nozzles used is found to yield an even higher precision. Furthermore, the high-velocity instability limit of regular jet breakup described by von Ohnesorge has been superseded by more than a factor of two without entering the wind-induced instability regime, and monodisperse droplet generation was

Automated Damage Assessment System for Ballistic Protective Inserts Using Low Frequency Ultrasonics

National Research Council Canada - National Science Library

Godinez-Azcuaga, Valery F; Ozevin, Didem; Finlayson, Richard D; Colanto, David

2006-01-01

.... Radiography and low frequency ultrasonics are two methods that can provide information about the condition of a BPI, with respect to cracking and porosity in the ceramic plate and debonding between layers...

An improved phase-locked loop method for automatic resonance frequency tracing based on static capacitance broadband compensation for a high-power ultrasonic transducer.

Science.gov (United States)

Dong, Hui-juan; Wu, Jian; Zhang, Guang-yu; Wu, Han-fu

2012-02-01

The phase-locked loop (PLL) method is widely used for automatic resonance frequency tracing (ARFT) of high-power ultrasonic transducers, which are usually vibrating systems with high mechanical quality factor (Qm). However, a heavily-loaded transducer usually has a low Qm because the load has a large mechanical loss. In this paper, a series of theoretical analyses is carried out to detail why the traditional PLL method could cause serious frequency tracing problems, including loss of lock, antiresonance frequency tracing, and large tracing errors. The authors propose an improved ARFT method based on static capacitance broadband compensation (SCBC), which is able to address these problems. Experiments using a generator based on the novel method were carried out using crude oil as the transducer load. The results obtained have demonstrated the effectiveness of the novel method, compared with the conventional PLL method, in terms of improved tracing accuracy (±9 Hz) and immunity to antiresonance frequency tracing and loss of lock.

Multiple-image hiding using super resolution reconstruction in high-frequency domains

Science.gov (United States)

Li, Xiao-Wei; Zhao, Wu-Xiang; Wang, Jun; Wang, Qiong-Hua

2017-12-01

In this paper, a robust multiple-image hiding method using the computer-generated integral imaging and the modified super-resolution reconstruction algorithm is proposed. In our work, the host image is first transformed into frequency domains by cellular automata (CA), to assure the quality of the stego-image, the secret images are embedded into the CA high-frequency domains. The proposed method has the following advantages: (1) robustness to geometric attacks because of the memory-distributed property of elemental images, (2) increasing quality of the reconstructed secret images as the scheme utilizes the modified super-resolution reconstruction algorithm. The simulation results show that the proposed multiple-image hiding method outperforms other similar hiding methods and is robust to some geometric attacks, e.g., Gaussian noise and JPEG compression attacks.

Low velocity target detection based on time-frequency image for high frequency ground wave radar

Institute of Scientific and Technical Information of China (English)

YAN Songhua; WU Shicai; WEN Biyang

2007-01-01

The Doppler spectral broadening resulted from non-stationary movement of target and radio-frequency interference will decrease the veracity of target detection by high frequency ground wave(HEGW)radar.By displaying the change of signal energy on two dimensional time-frequency images based on time-frequency analysis,a new mathematical morphology method to distinguish target from nonlinear time-frequency curves is presented.The analyzed results from the measured data verify that with this new method the target can be detected correctly from wide Doppler spectrum.

Monitoring Protein Fouling on Polymeric Membranes Using Ultrasonic Frequency-Domain Reflectometry

Directory of Open Access Journals (Sweden)

Robin Fong

2011-08-01

Full Text Available Novel signal-processing protocols were used to extend the in situ sensitivity of ultrasonic frequency-domain reflectometry (UFDR for real-time monitoring of microfiltration (MF membrane fouling during protein purification. Different commercial membrane materials, with a nominal pore size of 0.2 µm, were challenged using bovine serum albumin (BSA and amylase as model proteins. Fouling induced by these proteins was observed in flat-sheet membrane filtration cells operating in a laminar cross-flow regime. The detection of membrane-associated proteins using UFDR was determined by applying rigorous statistical methodology to reflection spectra of ultrasonic signals obtained during membrane fouling. Data suggest that the total power reflected from membrane surfaces changes in response to protein fouling at concentrations as low as 14 μg/cm2, and results indicate that ultrasonic spectra can be leveraged to detect and monitor protein fouling on commercial MF membranes.

Study on electrical impedance matching for broadband ultrasonic transducer

Energy Technology Data Exchange (ETDEWEB)

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

2017-02-15

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

Fiber-optic Michelson interferometer fixed in a tilted tube for direction-dependent ultrasonic detection

Science.gov (United States)

Gang, Tingting; Hu, Manli; Qiao, Xueguang; Li, JiaCheng; Shao, Zhihua; Tong, Rongxin; Rong, Qiangzhou

2017-01-01

A fiber-optic interferometer is proposed and demonstrated experimentally for ultrasonic detection. The sensor consists of a compact Michelson interferometer (MI), which is fixed in a tilted-tube end-face (45°). Thin gold films are used for the reflective coatings of two arms and one of the interference arms is etched serving as the sensing arm. The spectral sideband filter technique is used to interrogate the continuous and pulse ultrasonic signals (with frequency of 300 KHz). Furthermore, because of the asymmetrical structure of the sensor, it presents strong direction-dependent ultrasonic sensitivity, such that the sensor can be considered a vector detector. The experimental results show that the sensor is highly sensitive to ultrasonic signals, and thus it can be a candidate for ultrasonic imaging of seismic physical models.

Flaw-size measurement in a weld samples by ultrasonic frequency analysis

International Nuclear Information System (INIS)

Adler, L.; Cook, K.V.; Whaley, H.L. Jr.; McClung, R.W.

1975-01-01

An ultrasonic frequency-analysis technique was developed and applies to characterize flaws in an 8-in. (203-mm) thick heavy-section steel weld specimen. The technique applies a multitransducer system. The spectrum of the received broad-band signal is frequency analyzed at two different receivers for each of the flaws. From the two spectra, the size and orientation of the flaw are determined by the use of an analytic model proposed earlier. (auth)

Imaging ultrasonic dispersive guided wave energy in long bones using linear radon transform.

Science.gov (United States)

Tran, Tho N H T; Nguyen, Kim-Cuong T; Sacchi, Mauricio D; Le, Lawrence H

2014-11-01

Multichannel analysis of dispersive ultrasonic energy requires a reliable mapping of the data from the time-distance (t-x) domain to the frequency-wavenumber (f-k) or frequency-phase velocity (f-c) domain. The mapping is usually performed with the classic 2-D Fourier transform (FT) with a subsequent substitution and interpolation via c = 2πf/k. The extracted dispersion trajectories of the guided modes lack the resolution in the transformed plane to discriminate wave modes. The resolving power associated with the FT is closely linked to the aperture of the recorded data. Here, we present a linear Radon transform (RT) to image the dispersive energies of the recorded ultrasound wave fields. The RT is posed as an inverse problem, which allows implementation of the regularization strategy to enhance the focusing power. We choose a Cauchy regularization for the high-resolution RT. Three forms of Radon transform: adjoint, damped least-squares, and high-resolution are described, and are compared with respect to robustness using simulated and cervine bone data. The RT also depends on the data aperture, but not as severely as does the FT. With the RT, the resolution of the dispersion panel could be improved up to around 300% over that of the FT. Among the Radon solutions, the high-resolution RT delineated the guided wave energy with much better imaging resolution (at least 110%) than the other two forms. The Radon operator can also accommodate unevenly spaced records. The results of the study suggest that the high-resolution RT is a valuable imaging tool to extract dispersive guided wave energies under limited aperture. Copyright © 2014 World Federation for Ultrasound in Medicine & Biology. Published by Elsevier Inc. All rights reserved.

Progress towards in vitro quantitative imaging of human femur using compound quantitative ultrasonic tomography

International Nuclear Information System (INIS)

Lasaygues, Philippe; Ouedraogo, Edgard; Lefebvre, Jean-Pierre; Gindre, Marcel; Talmant, Marilyne; Laugier, Pascal

2005-01-01

The objective of this study is to make cross-sectional ultrasonic quantitative tomography of the diaphysis of long bones. Ultrasonic propagation in bones is affected by the severe mismatch between the acoustic properties of this biological solid and those of the surrounding soft medium, namely, the soft tissues in vivo or water in vitro. Bone imaging is then a nonlinear inverse-scattering problem. In this paper, we showed that in vitro quantitative images of sound velocities in a human femur cross section could be reconstructed by combining ultrasonic reflection tomography (URT), which provides images of the macroscopic structure of the bone, and ultrasonic transmission tomography (UTT), which provides quantitative images of the sound velocity. For the shape, we developed an image-processing tool to extract the external and internal boundaries and cortical thickness measurements. For velocity mapping, we used a wavelet analysis tool adapted to ultrasound, which allowed us to detect precisely the time of flight from the transmitted signals. A brief review of the ultrasonic tomography that we developed using correction algorithms of the wavepaths and compensation procedures are presented. Also shown are the first results of our analyses on models and specimens of long bone using our new iterative quantitative protocol

Defectoscopy of direct laser sintered metals by low transmission ultrasonic frequencies

Directory of Open Access Journals (Sweden)

Ebersold Zoran

2012-01-01

Full Text Available This paper focuses on the improvement of ultrasonic defectoscopy used for machine elements produced by direct laser metal sintering. The direct laser metal sintering process introduces the mixed metal powder and performs its subsequent laser consolidation in a single production step. Mechanical elements manufactured by laser sintering often contain many hollow cells due to weight reduction. The popular pulse echo defectoscopy method employing very high frequencies of several GHz is not successful on these samples. The aim of this paper is to present quadraphonic transmission ultrasound defectoscopy which uses low range frequencies of few tens of kHz. Therefore, the advantage of this method is that it enables defectoscopy for honeycombed materials manufactured by direct laser sintering. This paper presents the results of testing performed on AlSi12 sample. [Projekat Ministarstva nauke Republike Srbije, br. OI 172057

Applications of a nanocomposite-inspired in-situ broadband ultrasonic sensor to acousto-ultrasonics-based passive and active structural health monitoring.

Science.gov (United States)

Liu, Menglong; Zeng, Zhihui; Xu, Hao; Liao, Yaozhong; Zhou, Limin; Zhang, Zhong; Su, Zhongqing

2017-07-01

A novel nanocomposite-inspired in-situ broadband ultrasonic sensor previously developed, with carbon black as the nanofiller and polyvinylidene fluoride as the matrix, was networked for acousto-ultrasonic wave-based passive and active structural health monitoring (SHM). Being lightweight and small, this kind of sensor was proven to be capable of perceiving strain perturbation in virtue of the tunneling effect in the formed nanofiller conductive network when acousto-ultrasonic waves traverse the sensor. Proof-of-concept validation was implemented, to examine the sensor performance in responding to acousto-ultrasonic waves in a broad frequency regime: from acoustic emission (AE) of lower frequencies to guided ultrasonic waves (GUWs) of higher frequencies. Results have demonstrated the high fidelity, ultrafast response and high sensitivity of the sensor to acousto-ultrasonic waves up to 400kHz yet with an ultra-low magnitude (of the order of micro-strain). The sensor is proven to possess sensitivity and accuracy comparable with commercial piezoelectric ultrasonic transducers, whereas with greater flexibility in accommodating curved structural surfaces. Application paradigms of using the sensor for damage evaluation have spotlighted the capability of the sensor in compromising "sensing cost" with "sensing effectiveness" for passive AE- or active GUW-based SHM. Copyright © 2017 Elsevier B.V. All rights reserved.

Nonlinear ultrasonic stimulated thermography for damage assessment in isotropic fatigued structures

Science.gov (United States)

Fierro, Gian Piero Malfense; Calla', Danielle; Ginzburg, Dmitri; Ciampa, Francesco; Meo, Michele

2017-09-01

Traditional non-destructive evaluation (NDE) and structural health monitoring (SHM) systems are used to analyse that a structure is free of any harmful damage. However, these techniques still lack sensitivity to detect the presence of material micro-flaws in the form of fatigue damage and often require time-consuming procedures and expensive equipment. This research work presents a novel "nonlinear ultrasonic stimulated thermography" (NUST) method able to overcome some of the limitations of traditional linear ultrasonic/thermography NDE-SHM systems and to provide a reliable, rapid and cost effective estimation of fatigue damage in isotropic materials. Such a hybrid imaging approach combines the high sensitivity of nonlinear acoustic/ultrasonic techniques to detect micro-damage, with local defect frequency selection and infrared imaging. When exciting structures with an optimised frequency, nonlinear elastic waves are observed and higher frictional work at the fatigue damaged area is generated due to clapping and rubbing of the crack faces. This results in heat at cracked location that can be measured using an infrared camera. A Laser Vibrometer (LV) was used to evaluate the extent that individual frequency components contribute to the heating of the damage region by quantifying the out-of-plane velocity associated with the fundamental and second order harmonic responses. It was experimentally demonstrated the relationship between a nonlinear ultrasound parameter (βratio) of the material nonlinear response to the actual temperature rises near the crack. These results demonstrated that heat generation at damaged regions could be amplified by exciting at frequencies that provide nonlinear responses, thus improving the imaging of material damage and the reliability of NUST in a quick and reproducible manner.

Motion Estimation Using the Firefly Algorithm in Ultrasonic Image Sequence of Soft Tissue

Directory of Open Access Journals (Sweden)

Chih-Feng Chao

2015-01-01

Full Text Available Ultrasonic image sequence of the soft tissue is widely used in disease diagnosis; however, the speckle noises usually influenced the image quality. These images usually have a low signal-to-noise ratio presentation. The phenomenon gives rise to traditional motion estimation algorithms that are not suitable to measure the motion vectors. In this paper, a new motion estimation algorithm is developed for assessing the velocity field of soft tissue in a sequence of ultrasonic B-mode images. The proposed iterative firefly algorithm (IFA searches for few candidate points to obtain the optimal motion vector, and then compares it to the traditional iterative full search algorithm (IFSA via a series of experiments of in vivo ultrasonic image sequences. The experimental results show that the IFA can assess the vector with better efficiency and almost equal estimation quality compared to the traditional IFSA method.

Reconstruction from gamma radiography and ultrasonic images

International Nuclear Information System (INIS)

Gautier, S.; Lavayssiere, B.; Idier, J.; Mohammad-Djafari, A.

1998-02-01

This work deals with the three-dimensional reconstruction from gamma radiographic and ultrasonic images. Such an issue belongs to the field of data fusion since the data provide complementary information. The two sets of data are independently related to two sets of parameters: gamma ray attenuation and ultrasonic reflectivity. The fusion problem is addressed in a Bayesian framework; the kingpin of the task is then to define a joint a priori model for both attenuation and reflectivity. Thus, the developing of this model and the entailed joint estimation constitute the principal contribution of this work. The results of real data treatments demonstrate the validity of this method as compared to a sequential approach of the two sets of data

Robust frequency diversity based algorithm for clutter noise reduction of ultrasonic signals using multiple sub-spectrum phase coherence

Energy Technology Data Exchange (ETDEWEB)

Gongzhang, R.; Xiao, B.; Lardner, T.; Gachagan, A. [Centre for Ultrasonic Engineering, University of Strathclyde, Glasgow, G1 1XW (United Kingdom); Li, M. [School of Engineering, University of Glasgow, Glasgow, G12 8QQ (United Kingdom)

2014-02-18

This paper presents a robust frequency diversity based algorithm for clutter reduction in ultrasonic A-scan waveforms. The performance of conventional spectral-temporal techniques like Split Spectrum Processing (SSP) is highly dependent on the parameter selection, especially when the signal to noise ratio (SNR) is low. Although spatial beamforming offers noise reduction with less sensitivity to parameter variation, phased array techniques are not always available. The proposed algorithm first selects an ascending series of frequency bands. A signal is reconstructed for each selected band in which a defect is present when all frequency components are in uniform sign. Combining all reconstructed signals through averaging gives a probability profile of potential defect position. To facilitate data collection and validate the proposed algorithm, Full Matrix Capture is applied on the austenitic steel and high nickel alloy (HNA) samples with 5MHz transducer arrays. When processing A-scan signals with unrefined parameters, the proposed algorithm enhances SNR by 20dB for both samples and consequently, defects are more visible in B-scan images created from the large amount of A-scan traces. Importantly, the proposed algorithm is considered robust, while SSP is shown to fail on the austenitic steel data and achieves less SNR enhancement on the HNA data.

In vivo photoacoustics and high frequency ultrasound imaging of mechanical high intensity focused ultrasound (HIFU) ablation.

Science.gov (United States)

Daoudi, Khalid; Hoogenboom, Martijn; den Brok, Martijn; Eikelenboom, Dylan; Adema, Gosse J; Fütterer, Jürgen J; de Korte, Chris L

2017-04-01

The thermal effect of high intensity focused ultrasound (HIFU) has been clinically exploited over a decade, while the mechanical HIFU is still largely confined to laboratory investigations. This is in part due to the lack of adequate imaging techniques to better understand the in-vivo pathological and immunological effects caused by the mechanical treatment. In this work, we explore the use of high frequency ultrasound (US) and photoacoustics (PA) as a potential tool to evaluate the effect of mechanical ablation in-vivo , e.g. boiling histotripsy. Two mice bearing a neuroblastoma tumor in the right leg were ablated using an MRI-HIFU system conceived for small animals and monitored using MRI thermometry. High frequency US and PA imaging were performed before and after the HIFU treatment. Afterwards, the tumor was resected for further assessment and evaluation of the ablated region using histopathology. High frequency US imaging revealed the presence of liquefied regions in the treated area together with fragmentized tissue which appeared with different reflecting proprieties compared to the surrounding tissue. Photoacoustic imaging on the other hand revealed the presence of deoxygenated blood within the tumor after the ablation due to the destruction of blood vessel network while color Doppler imaging confirmed the blood vessel network destruction within the tumor. The treated area and the presence of red blood cells detected by photoacoustics were further confirmed by the histopathology. This feasibility study demonstrates the potential of high frequency US and PA approach for assessing in-vivo the effect of mechanical HIFU tumor ablation.

Inspection of copper canisters for spent nuclear fuel by means of ultrasound. Electron beam evaluation, harmonic imaging, materials characterization, and ultrasonic modelling

International Nuclear Information System (INIS)

Wu Ping; Lingvall, Fredrik; Stepinski, Tadeusz

2000-12-01

This report presents the research in the sixth phase that is concerned with ultrasonic techniques for assessing electron beam (EB) welds in copper canisters. The research has been carried out in three main aspects: (1) comparative inspections of EB welds, (2) EB weld evaluation, and (3) quantitative evaluation of attenuation in copper. Comparative inspections of EB welds in two copper canister blocks have been made by means of ultrasound and radiography. Comparison of the inspected results demonstrate that both techniques complement each other very well. The radiographic technique on the whole gives relatively better spatial resolution but low contrast in radiographs. It can reliably detect voids in EB, but cannot provide information about material structure in the EB weld. Ultrasonic technique provides information about flaw locations and shapes similar to the radiographs. Moreover, it can easily distinguish welded and non-welded zones and be used to study weld's macro- and microstructure. The defects in ultrasonic images often show higher contrast, and some flaw indications may be seen in ultrasonic inspection but not in radiographs. But small flaws are hard to distinguish from grain noise. For EB weld evaluation, first, scattering from EB weld has been investigated using three broadband transducers with different center frequencies. The investigation has shown that more information on scattering and attenuation can be exploited in this case so that the EB welds can be better characterized, and that the best frequency range for characterizing welds is 2 - 5 MHz. Secondly, harmonic imaging (HI) of EB welds have been studied using two different sources of harmonics: (i) transducer harmonics, originating from the high-order resonant modes of transmitters excited by a broadband pulse, and (ii) material harmonics, stemming from the nonlinear distortion of waves propagating in materials. The transducer HI exploits additional information due to transducer harmonics, and

Inspection of copper canisters for spent nuclear fuel by means of ultrasound. Electron beam evaluation, harmonic imaging, materials characterization, and ultrasonic modelling

Energy Technology Data Exchange (ETDEWEB)

Wu Ping; Lingvall, Fredrik; Stepinski, Tadeusz [Uppsala Univ. (Sweden). Dept. of Materials Science

2000-12-01

This report presents the research in the sixth phase that is concerned with ultrasonic techniques for assessing electron beam (EB) welds in copper canisters. The research has been carried out in three main aspects: (1) comparative inspections of EB welds, (2) EB weld evaluation, and (3) quantitative evaluation of attenuation in copper. Comparative inspections of EB welds in two copper canister blocks have been made by means of ultrasound and radiography. Comparison of the inspected results demonstrate that both techniques complement each other very well. The radiographic technique on the whole gives relatively better spatial resolution but low contrast in radiographs. It can reliably detect voids in EB, but cannot provide information about material structure in the EB weld. Ultrasonic technique provides information about flaw locations and shapes similar to the radiographs. Moreover, it can easily distinguish welded and non-welded zones and be used to study weld's macro- and microstructure. The defects in ultrasonic images often show higher contrast, and some flaw indications may be seen in ultrasonic inspection but not in radiographs. But small flaws are hard to distinguish from grain noise. For EB weld evaluation, first, scattering from EB weld has been investigated using three broadband transducers with different center frequencies. The investigation has shown that more information on scattering and attenuation can be exploited in this case so that the EB welds can be better characterized, and that the best frequency range for characterizing welds is 2 - 5 MHz. Secondly, harmonic imaging (HI) of EB welds have been studied using two different sources of harmonics: (i) transducer harmonics, originating from the high-order resonant modes of transmitters excited by a broadband pulse, and (ii) material harmonics, stemming from the nonlinear distortion of waves propagating in materials. The transducer HI exploits additional information due to transducer harmonics

Warped frequency transform analysis of ultrasonic guided waves in long bones

Science.gov (United States)

De Marchi, L.; Baravelli, E.; Xu, K.; Ta, D.; Speciale, N.; Marzani, A.; Viola, E.

2010-03-01

Long bones can be seen as irregular hollow tubes, in which, for a given excitation frequency, many ultrasonic Guided Waves (GWs) can propagate. The analysis of GWs is potential to reflect more information on both geometry and material properties of the bone than any other method (such as dual-energy X-ray absorptiometry, or quantitative computed tomography), and can be used in the assessment of osteoporosis and in the evaluation of fracture healing. In this study, time frequency representations (TFRs) were used to gain insights into the expected behavior of GWs in bones. To this aim, we implemented a dedicated Warped Frequency Transform (WFT) which decomposes the spectrotemporal components of the different propagating modes by selecting an appropriate warping map to reshape the frequency axis. The map can be designed once the GWs group velocity dispersion curves can be predicted. To this purpose, the bone is considered as a hollow cylinder with inner and outer diameter of 16.6 and 24.7 mm, respectively, and linear poroelastic material properties in agreement with the low level of stresses induced by the waves. Timetransient events obtained experimentally, via a piezoelectric ultrasonic set-up applied to bovine tibiae, are analyzed. The results show that WFT limits interference patterns which appear with others TFRs (such as scalograms or warpograms) and produces a sparse representation suitable for characterization purposes. In particular, the mode-frequency combinations propagating with minimal losses are identified.

High-frequency ultrasound for intraoperative margin assessments in breast conservation surgery: a feasibility study

International Nuclear Information System (INIS)

Doyle, Timothy E; Neumayer, Leigh A; Factor, Rachel E; Ellefson, Christina L; Sorensen, Kristina M; Ambrose, Brady J; Goodrich, Jeffrey B; Hart, Vern P; Jensen, Scott C; Patel, Hemang

2011-01-01

In addition to breast imaging, ultrasound offers the potential for characterizing and distinguishing between benign and malignant breast tissues due to their different microstructures and material properties. The aim of this study was to determine if high-frequency ultrasound (20-80 MHz) can provide pathology sensitive measurements for the ex vivo detection of cancer in margins during breast conservation surgery. Ultrasonic tests were performed on resected margins and other tissues obtained from 17 patients, resulting in 34 specimens that were classified into 15 pathology categories. Pulse-echo and through-transmission measurements were acquired from a total of 57 sites on the specimens using two single-element 50-MHz transducers. Ultrasonic attenuation and sound speed were obtained from time-domain waveforms. The waveforms were further processed with fast Fourier transforms to provide ultrasonic spectra and cepstra. The ultrasonic measurements and pathology types were analyzed for correlations. The specimens were additionally re-classified into five pathology types to determine specificity and sensitivity values. The density of peaks in the ultrasonic spectra, a measure of spectral structure, showed significantly higher values for carcinomas and precancerous pathologies such as atypical ductal hyperplasia than for normal tissue. The slopes of the cepstra for non-malignant pathologies displayed significantly greater values that differentiated them from the normal and malignant tissues. The attenuation coefficients were sensitive to fat necrosis, fibroadenoma, and invasive lobular carcinoma. Specificities and sensitivities for differentiating pathologies from normal tissue were 100% and 86% for lobular carcinomas, 100% and 74% for ductal carcinomas, 80% and 82% for benign pathologies, and 80% and 100% for fat necrosis and adenomas. Specificities and sensitivities were also determined for differentiating each pathology type from the other four using a multivariate

High-frequency ultrasound for intraoperative margin assessments in breast conservation surgery: a feasibility study

Directory of Open Access Journals (Sweden)

Hart Vern P

2011-10-01

Full Text Available Abstract Background In addition to breast imaging, ultrasound offers the potential for characterizing and distinguishing between benign and malignant breast tissues due to their different microstructures and material properties. The aim of this study was to determine if high-frequency ultrasound (20-80 MHz can provide pathology sensitive measurements for the ex vivo detection of cancer in margins during breast conservation surgery. Methods Ultrasonic tests were performed on resected margins and other tissues obtained from 17 patients, resulting in 34 specimens that were classified into 15 pathology categories. Pulse-echo and through-transmission measurements were acquired from a total of 57 sites on the specimens using two single-element 50-MHz transducers. Ultrasonic attenuation and sound speed were obtained from time-domain waveforms. The waveforms were further processed with fast Fourier transforms to provide ultrasonic spectra and cepstra. The ultrasonic measurements and pathology types were analyzed for correlations. The specimens were additionally re-classified into five pathology types to determine specificity and sensitivity values. Results The density of peaks in the ultrasonic spectra, a measure of spectral structure, showed significantly higher values for carcinomas and precancerous pathologies such as atypical ductal hyperplasia than for normal tissue. The slopes of the cepstra for non-malignant pathologies displayed significantly greater values that differentiated them from the normal and malignant tissues. The attenuation coefficients were sensitive to fat necrosis, fibroadenoma, and invasive lobular carcinoma. Specificities and sensitivities for differentiating pathologies from normal tissue were 100% and 86% for lobular carcinomas, 100% and 74% for ductal carcinomas, 80% and 82% for benign pathologies, and 80% and 100% for fat necrosis and adenomas. Specificities and sensitivities were also determined for differentiating each

Radiation-Force Assisted Targeting Facilitates Ultrasonic Molecular Imaging

Directory of Open Access Journals (Sweden)

Shukui Zhao

2004-07-01

Full Text Available Ultrasonic molecular imaging employs contrast agents, such as microbubbles, nanoparticles, or liposomes, coated with ligands specific for receptors expressed on cells at sites of angiogenesis, inflammation, or thrombus. Concentration of these highly echogenic contrast agents at a target site enhances the ultrasound signal received from that site, promoting ultrasonic detection and analysis of disease states. In this article, we show that acoustic radiation force can be used to displace targeted contrast agents to a vessel wall, greatly increasing the number of agents binding to available surface receptors. We provide a theoretical evaluation of the magnitude of acoustic radiation force and show that it is possible to displace micron-sized agents physiologically relevant distances. Following this, we show in a series of experiments that acoustic radiation force can enhance the binding of targeted agents: The number of biotinylated microbubbles adherent to a synthetic vessel coated with avidin increases as much as 20-fold when acoustic radiation force is applied; the adhesion of contrast agents targeted to αvβ3 expressed on human umbilical vein endothelial cells increases 27-fold within a mimetic vessel when radiation force is applied; and finally, the image signal-to-noise ratio in a phantom vessel increases up to 25 dB using a combination of radiation force and a targeted contrast agent, over use of a targeted contrast agent alone.

Data collection instrumentation for ultrasonic imaging under sodium

International Nuclear Information System (INIS)

McKnight, J.A.; Parker, J.A.

1981-05-01

A team at the Risley Nuclear Power Development Establishment has been developing apparatus for the production of ultrasonic images under opaque liquids. The technique is intended for examining objects under liquid sodium at 300 0 C, and the range of possible methods is restricted as a consequence. The method chosen uses pulse-echo ultrasonics combined with mechanical scanning to assemble the final image. The data is collected using a CAMAC system under the control of an Intel 8080 microprocessor. The data is analysed separately and presented on a colour display using a DEC LSl 11 microprocessor controlled system. To achieve the required performance a number of special electronic assemblies were made. A single image requires 2.5 M byte of data. The cost of using the apparatus on a Fast Reactor is such that it is prudent to provide back-up data collection through a data link, and to maximise the data collection rate. This causes problems with the interrupt cycle time of the CAMAC controller, which can be resolved using synchronous programs specifically tailored to each application. (author)

Physical mechanisms of megahertz vibrations and nonlinear detection in ultrasonic force and related microscopies

Energy Technology Data Exchange (ETDEWEB)

Bosse, J. L.; Huey, B. D. [Department of Materials Science and Engineering, 97 North Eagleville Road, Unit 3136, Storrs, Connecticut 06269-3136 (United States); Tovee, P. D.; Kolosov, O. V., E-mail: o.kolosov@lancaster.ac.uk [Department of Physics, Lancaster University, Lancaster LA1 4YB (United Kingdom)

2014-04-14

Use of high frequency (HF) vibrations at MHz frequencies in Atomic Force Microscopy (AFM) advanced nanoscale property mapping to video rates, allowed use of cantilever dynamics for mapping nanomechanical properties of stiff materials, sensing μs time scale phenomena in nanostructures, and enabled detection of subsurface features with nanoscale resolution. All of these methods critically depend on the generally poor characterized HF behaviour of AFM cantilevers in contact with a studied sample, spatial and frequency response of piezotransducers, and transfer of ultrasonic vibrations between the probe and a specimen. Focusing particularly on Ultrasonic Force Microscopy (UFM), this work is also applicable to waveguide UFM, heterodyne force microscopy, and near-field holographic microscopy, all methods that exploit nonlinear tip-surface force interactions at high frequencies. Leveraging automated multidimensional measurements, spectroscopic UFM (sUFM) is introduced to investigate a range of common experimental parameters, including piezotransducer excitation frequency, probed position, ultrasonic amplitude, cantilever geometry, spring constant, and normal force. Consistent with studies of influence of each of these factors, the data-rich sUFM signatures allow efficient optimization of ultrasonic-AFM based measurements, leading to best practices recommendations of using longer cantilevers with lower fundamental resonance, while at the same time increasing the central frequency of HF piezo-actuators, and only comparing results within areas on the order of few μm{sup 2} unless calibrated directly or compared with in-the-imaged area standards. Diverse materials such as Si, Cr, and photoresist are specifically investigated. This work thereby provides essential insight into the reliable use of MHz vibrations with AFM and provides direct evidence substantiating phenomena such as sensitivity to adhesion, diminished friction for certain ultrasonic conditions, and the

Physical mechanisms of megahertz vibrations and nonlinear detection in ultrasonic force and related microscopies

International Nuclear Information System (INIS)

Bosse, J. L.; Huey, B. D.; Tovee, P. D.; Kolosov, O. V.

2014-01-01

Use of high frequency (HF) vibrations at MHz frequencies in Atomic Force Microscopy (AFM) advanced nanoscale property mapping to video rates, allowed use of cantilever dynamics for mapping nanomechanical properties of stiff materials, sensing μs time scale phenomena in nanostructures, and enabled detection of subsurface features with nanoscale resolution. All of these methods critically depend on the generally poor characterized HF behaviour of AFM cantilevers in contact with a studied sample, spatial and frequency response of piezotransducers, and transfer of ultrasonic vibrations between the probe and a specimen. Focusing particularly on Ultrasonic Force Microscopy (UFM), this work is also applicable to waveguide UFM, heterodyne force microscopy, and near-field holographic microscopy, all methods that exploit nonlinear tip-surface force interactions at high frequencies. Leveraging automated multidimensional measurements, spectroscopic UFM (sUFM) is introduced to investigate a range of common experimental parameters, including piezotransducer excitation frequency, probed position, ultrasonic amplitude, cantilever geometry, spring constant, and normal force. Consistent with studies of influence of each of these factors, the data-rich sUFM signatures allow efficient optimization of ultrasonic-AFM based measurements, leading to best practices recommendations of using longer cantilevers with lower fundamental resonance, while at the same time increasing the central frequency of HF piezo-actuators, and only comparing results within areas on the order of few μm 2 unless calibrated directly or compared with in-the-imaged area standards. Diverse materials such as Si, Cr, and photoresist are specifically investigated. This work thereby provides essential insight into the reliable use of MHz vibrations with AFM and provides direct evidence substantiating phenomena such as sensitivity to adhesion, diminished friction for certain ultrasonic conditions, and the particular

Tridimensional ultrasonic images analysis for the in service inspection of fast breeder reactors

International Nuclear Information System (INIS)

Dancre, M.

1999-11-01

Tridimensional image analysis provides a set of methods for the intelligent extraction of information in order to visualize, recognize or inspect objects in volumetric images. In this field of research, we are interested in algorithmic and methodological aspects to extract surface visual information embedded in volume ultrasonic images. The aim is to help a non-acoustician operator, possibly the system itself, to inspect surfaces of vessel and internals in Fast Breeder Reactors (FBR). Those surfaces are immersed in liquid metal, what justifies the ultrasonic technology choice. We expose firstly a state of the art on the visualization of volume ultrasonic images, the methods of noise analysis, the geometrical modelling for surface analysis and finally curves and surfaces matching. These four points are then inserted in a global analysis strategy that relies on an acoustical analysis (echoes recognition), an object analysis (object recognition and reconstruction) and a surface analysis (surface defects detection). Few literature can be found on ultrasonic echoes recognition through image analysis. We suggest an original method that can be generalized to all images with structured and non-structured noise. From a technical point of view, this methodology applied to echoes recognition turns out to be a cooperative approach between morphological mathematics and snakes (active contours). An entropy maximization technique is required for volumetric data binarization. (author)

Radial vibration and ultrasonic field of a long tubular ultrasonic radiator.

Science.gov (United States)

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

2013-09-01

The radial vibration of a metal long circular tube is studied analytically and its electro-mechanical equivalent circuit is obtained. Based on the equivalent circuit, the radial resonance frequency equation is derived. The theoretical relationship between the radial resonance frequency and the geometrical dimensions is studied. Finite element method is used to simulate the radial vibration and the radiated ultrasonic field and the results are compared with those from the analytical method. It is concluded that the radial resonance frequency for a solid metal rod is larger than that for a metal tube with the same outer radius. The radial resonance frequencies from the analytical method are in good agreement with those from the numerical method. Based on the acoustic field analysis, it is concluded that the long metal tube with small wall thickness is superior to that with large wall thickness in producing radial vibration and ultrasonic radiation. Therefore, it is expected to be used as an effective radial ultrasonic radiator in ultrasonic sewage treatment, ultrasonic antiscale and descaling and other ultrasonic liquid handling applications. Copyright © 2013 Elsevier B.V. All rights reserved.

Lumber defect detection by ultrasonics

Science.gov (United States)

K. A. McDonald

1978-01-01

Ultrasonics, the technology of high-frequency sound, has been developed as a viable means for locating most defects In lumber for use in digital form in decision-making computers. Ultrasonics has the potential for locating surface and internal defects in lumber of all species, green or dry, and rough sawn or surfaced.

Head Injury and Intracranial Pressure Monitor Using Ultrasonic and Low-Frequency (ULFA) Detection

National Research Council Canada - National Science Library

Vo-Dinh, Tuan

2000-01-01

The main objective of this research project is the development of a non-invasive method and instrument for head injury detection and monitoring using a new approach based on ultrasonic and low-frequency acoustic (ULFA...

The potential of high resolution ultrasonic in-situ methods

International Nuclear Information System (INIS)

Schuster, K.

2010-01-01

Document available in extended abstract form only. In the framework of geomechanical assessment of final repository underground openings the knowledge of geophysical rock parameters are of importance. Ultrasonic methods proved to be good geophysical tools to provide appropriate high resolution parameters for the characterisation of rock. In this context the detection and characterisation of rock heterogeneities at different scales, including the Excavation Damaged/disturbed Zone (EDZ/EdZ) features, play an important role. Especially, kinematic and dynamic parameters derived from ultrasonic measurements can be linked very close to rock mechanic investigations and interpretations. BGR uses high resolution ultrasonic methods, starting with emitted frequencies of about 1 kHz (seismic) and going up to about 100 kHz. The method development is going on and appropriate research and investigations are performed since many years at different European radioactive waste disposal related underground research laboratories in different potential host rocks. The most frequented are: Mont Terri Rock Laboratory, Switzerland (Opalinus Clay, OPA), Underground Research Laboratory Meuse/Haute- Marne, France (Callovo-Oxfordian, COX), Underground Research Facility Mol, Belgium (Boom Clay, BC), Aespoe Hard Rock Laboratory, Sweden (granites), Rock Laboratory Grimsel, Switzerland (granites) and Asse salt mine, Germany (rock salt). The methods can be grouped into borehole based methods and noninvasive methods like refraction and reflection methods, which are performed in general from the drift wall. Additionally, as a combination of these both methods a sort of vertical seismic profiling (VSP) is applied. The best qualified method, or a combination of methods, have to be chosen according to the scientific questions and the local site conditions. The degree of spatial resolution of zones of interest or any kind of anomaly depends strongly on the distance of these objects to the ultrasonic

Ultrasonic techniques for measuring physical properties of fluids in harsh environments

Science.gov (United States)

Pantea, Cristian

Ultrasonic-based measurement techniques, either in the time domain or in the frequency domain, include a wide range of experimental methods for investigating physical properties of materials. This discussion is specifically focused on ultrasonic methods and instrumentation development for the determination of liquid properties at conditions typically found in subsurface environments (in the U.S., more than 80% of total energy needs are provided by subsurface energy sources). Such sensors require materials that can withstand harsh conditions of high pressure, high temperature and corrosiveness. These include the piezoelectric material, electrically conductive adhesives, sensor housings/enclosures, and the signal carrying cables, to name a few. A complete sensor package was developed for operation at high temperatures and pressures characteristic to geothermal/oil-industry reservoirs. This package is designed to provide real-time, simultaneous measurements of multiple physical parameters, such as temperature, pressure, salinity and sound speed. The basic principle for this sensor's operation is an ultrasonic frequency domain technique, combined with transducer resonance tracking. This multipurpose acoustic sensor can be used at depths of several thousand meters, temperatures up to 250 °C, and in a very corrosive environment. In the context of high precision measurement of sound speed, the determination of acoustic nonlinearity of liquids will also be discussed, using two different approaches: (i) the thermodynamic method, in which precise and accurate frequency domain sound speed measurements are performed at high pressure and high temperature, and (ii) a modified finite amplitude method, requiring time domain measurements of the second harmonic at room temperature. Efforts toward the development of an acoustic source of collimated low-frequency (10-150 kHz) beam, with applications in imaging, will also be presented.

Design of signal reception and processing system of embedded ultrasonic endoscope

Science.gov (United States)

Li, Ming; Yu, Feng; Zhang, Ruiqiang; Li, Yan; Chen, Xiaodong; Yu, Daoyin

2009-11-01

Embedded Ultrasonic Endoscope, based on embedded microprocessor and embedded real-time operating system, sends a micro ultrasonic probe into coelom through the biopsy channel of the Electronic Endoscope to get the fault histology features of digestive organs by rotary scanning, and acquires the pictures of the alimentary canal mucosal surface. At the same time, ultrasonic signals are processed by signal reception and processing system, forming images of the full histology of the digestive organs. Signal Reception and Processing System is an important component of Embedded Ultrasonic Endoscope. However, the traditional design, using multi-level amplifiers and special digital processing circuits to implement signal reception and processing, is no longer satisfying the standards of high-performance, miniaturization and low power requirements that embedded system requires, and as a result of the high noise that multi-level amplifier brought, the extraction of small signal becomes hard. Therefore, this paper presents a method of signal reception and processing based on double variable gain amplifier and FPGA, increasing the flexibility and dynamic range of the Signal Reception and Processing System, improving system noise level, and reducing power consumption. Finally, we set up the embedded experiment system, using a transducer with the center frequency of 8MHz to scan membrane samples, and display the image of ultrasonic echo reflected by each layer of membrane, with a frame rate of 5Hz, verifying the correctness of the system.

Practical approach to ultrasonic imaging using diffraction tomography

International Nuclear Information System (INIS)

Witten, A.; Tuggle, J.; Waag, R.C.

1988-01-01

A technique for ultrasonic imaging based on the theory of diffraction tomography is presented. The method utilizes a fixed, circular configuration of transmitters and detectors. This configuration was selected because it avoids many practical limitations associated with the design of a medical imaging device. Practical considerations also motivated the inclusion of effects associated with the transmitter beam pattern rather than pursuing the more conventional approach in which plane-wave illumination is required. In addition, the problem of separately imaging both density and compressibility variations is considered

Practical approach to ultrasonic imaging using diffraction tomography

Energy Technology Data Exchange (ETDEWEB)

Witten, A.; Tuggle, J.; Waag, R.C.

1988-04-01

A technique for ultrasonic imaging based on the theory of diffraction tomography is presented. The method utilizes a fixed, circular configuration of transmitters and detectors. This configuration was selected because it avoids many practical limitations associated with the design of a medical imaging device. Practical considerations also motivated the inclusion of effects associated with the transmitter beam pattern rather than pursuing the more conventional approach in which plane-wave illumination is required. In addition, the problem of separately imaging both density and compressibility variations is considered.

Study on the sandwich piezoelectric ceramic ultrasonic transducer in thickness vibration

International Nuclear Information System (INIS)

Lin Shuyu; Tian Hua

2008-01-01

A sandwich piezoelectric ceramic ultrasonic transducer in thickness vibration is studied. The transducer consists of front and back metal masses, and coaxially segmented, thickness polarized piezoelectric ceramic thin rings. For this kind of sandwich piezoelectric transducers in thickness vibration, it is required that the lateral dimension of the transducer is sufficiently large compared with its longitudinal dimension so that no lateral displacements in the transducer can occur (laterally clamped). In this paper, the thickness vibration of the piezoelectric ceramic stack consisting of a number of identical piezoelectric ceramic thin rings is analysed and its electro-mechanical equivalent circuit is obtained. The resonance frequency equation for the sandwich piezoelectric ceramic ultrasonic transducer in thickness vibration is derived. Based on the frequency equation, two sandwich piezoelectric ceramic ultrasonic transducers are designed and manufactured, and their resonance frequencies are measured. It is shown that the measured resonance frequencies are in good agreement with the theoretical results. This kind of sandwich piezoelectric ultrasonic transducer is expected to be used in megasonic ultrasonic cleaning and sonochemistry where high power and high frequency ultrasound is needed

Feasibility Study on Ultrasonic Waveguide Sensor for Under-Sodium Visualization of Sodium Fast Reactor

Energy Technology Data Exchange (ETDEWEB)

Joo, Young-Sang; Park, Chang-Gyu; Lee, Jae-Han; Lim, Sa-Hoe

2008-01-15

The reactor core and internal structures of a sodium-cooled fast reactor (SFR) can not be visually examined due to the opaque sodium. The examination of the internal structures is possible by using ultrasonics to penetrate the sodium. The under-sodium viewing technique using an ultrasonic wave should be applied for the in-service inspection of the reactor internals. Immersion sensors and waveguide sensors have been utilized for the under-sodium viewing application. The immersion sensor has a precise imaging capability, but may have high temperature restrictions and an uncertain life. The waveguide sensor can operate in a hostile environment, such as liquid metal at a high temperature in the presence of high radiation. The waveguide sensor has the advantages of simplicity and reliability, but limits in its movement. A new plate-type waveguide sensor has been developed to overcome the limitations of previous waveguide sensors. And a novel ultrasonic technique has been suggested. The technique is capable of steering a radiation beam of a waveguide sensor without a mechanical movement of the waveguide sensor. The control of the radiation beam angle can be achieved by a frequency tuning method of the excitation pulse in the dispersive low frequency range of the A{sub 0} Lamb wave. A waveguide sensor assembly has been designed for the actual application of undersodium visual inspection in sodium-cooled fast reactor. The main purpose of this study is achievement of feasibility of ultrasonic waveguide sensor technology to the application of undersodium viewing. Under-water C-scan imaging test was carried out by using 10 m long waveguide sensor assembly. It was confirmed that the test target could be clearly visualized and the resolution of C-scan image could be less than 2 mm.

Feasibility Study on Ultrasonic Waveguide Sensor for Under-Sodium Visualization of Sodium Fast Reactor

International Nuclear Information System (INIS)

Joo, Young-Sang; Park, Chang-Gyu; Lee, Jae-Han; Lim, Sa-Hoe

2008-01-01

The reactor core and internal structures of a sodium-cooled fast reactor (SFR) can not be visually examined due to the opaque sodium. The examination of the internal structures is possible by using ultrasonics to penetrate the sodium. The under-sodium viewing technique using an ultrasonic wave should be applied for the in-service inspection of the reactor internals. Immersion sensors and waveguide sensors have been utilized for the under-sodium viewing application. The immersion sensor has a precise imaging capability, but may have high temperature restrictions and an uncertain life. The waveguide sensor can operate in a hostile environment, such as liquid metal at a high temperature in the presence of high radiation. The waveguide sensor has the advantages of simplicity and reliability, but limits in its movement. A new plate-type waveguide sensor has been developed to overcome the limitations of previous waveguide sensors. And a novel ultrasonic technique has been suggested. The technique is capable of steering a radiation beam of a waveguide sensor without a mechanical movement of the waveguide sensor. The control of the radiation beam angle can be achieved by a frequency tuning method of the excitation pulse in the dispersive low frequency range of the A 0 Lamb wave. A waveguide sensor assembly has been designed for the actual application of undersodium visual inspection in sodium-cooled fast reactor. The main purpose of this study is achievement of feasibility of ultrasonic waveguide sensor technology to the application of undersodium viewing. Under-water C-scan imaging test was carried out by using 10 m long waveguide sensor assembly. It was confirmed that the test target could be clearly visualized and the resolution of C-scan image could be less than 2 mm

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

Directory of Open Access Journals (Sweden)

Rymantas J. Kazys

2017-01-01

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

Welding characteristics of 27, 40 and 67 kHz ultrasonic plastic welding systems using fundamental- and higher-resonance frequencies.

Science.gov (United States)

Tsujino, Jiromaru; Hongoh, Misugi; Yoshikuni, Masafumi; Hashii, Hidekazu; Ueoka, Tetsugi

2004-04-01

The welding characteristics of 27, 40 and 67 kHz ultrasonic plastic welding systems that are driven at only the fundamental-resonance frequency vibration were compared, and also those of the welding systems that were driven at the fundamental and several higher resonance frequencies simultaneously were studied. At high frequency, welding characteristics can be improved due to the larger vibration loss of plastic materials. For welding of rather thin or small specimens, as the fundamental frequency of these welding systems is higher and the numbers of driven higher frequencies are driven simultaneously, larger welded area and weld strength were obtained.

A new approach to ultrasonic elasticity imaging

Science.gov (United States)

Hoerig, Cameron; Ghaboussi, Jamshid; Fatemi, Mostafa; Insana, Michael F.

2016-04-01

Biomechanical properties of soft tissues can provide information regarding the local health status. Often the cells in pathological tissues can be found to form a stiff extracellular environment, which is a sensitive, early diagnostic indicator of disease. Quasi-static ultrasonic elasticity imaging provides a way to image the mechanical properties of tissues. Strain images provide a map of the relative tissue stiffness, but ambiguities and artifacts limit its diagnostic value. Accurately mapping intrinsic mechanical parameters of a region may increase diagnostic specificity. However, the inverse problem, whereby force and displacement estimates are used to estimate a constitutive matrix, is ill conditioned. Our method avoids many of the issues involved with solving the inverse problem, such as unknown boundary conditions and incomplete information about the stress field, by building an empirical model directly from measured data. Surface force and volumetric displacement data gathered during imaging are used in conjunction with the AutoProgressive method to teach artificial neural networks the stress-strain relationship of tissues. The Autoprogressive algorithm has been successfully used in many civil engineering applications and to estimate ocular pressure and corneal stiffness; here, we are expanding its use to any tissues imaged ultrasonically. We show that force-displacement data recorded with an ultrasound probe and displacements estimated at a few points in the imaged region can be used to estimate the full stress and strain vectors throughout an entire model while only assuming conservation laws. We will also demonstrate methods to parameterize the mechanical properties based on the stress-strain response of trained neural networks. This method is a fundamentally new approach to medical elasticity imaging that for the first time provides full stress and strain vectors from one set of observation data.

Air-Coupled Ultrasonic Receivers with High Electromechanical Coupling PMN-32%PT Strip-Like Piezoelectric Elements

Directory of Open Access Journals (Sweden)

Rymantas J. Kazys

2017-10-01

Full Text Available For improvement of the efficiency of air-coupled ultrasonic transducers PMN-32%PT piezoelectric crystals which possess very high piezoelectric properties may be used. The electromechanical coupling factor of such crystals for all main vibration modes such as the thickness extension and transverse extension modes is more than 0.9. Operation of ultrasonic transducers with such piezoelectric elements in transmitting and receiving modes is rather different. Therefore, for transmission and reception of ultrasonic signals, separate piezoelectric elements with different dimensions must be used. The objective of this research was development of novel air-coupled ultrasonic receivers with PMN-32%PT strip-like piezoelectric elements vibrating in a transverse-extension mode with electromechanically controlled operation and suitable for applications in ultrasonic arrays. Performance of piezoelectric receivers made of the PMN-32%PT strip-like elements vibrating in this mode may be efficiently controlled by selecting geometry of the electrodes covering side surfaces of the piezoelectric element. It is equivalent to introduction of electromechanical damping which does not require any additional backing element. For this purpose; we have proposed the continuous electrodes to divide into two pairs of electrodes. The one pair is used to pick up the electric signal; another one is exploited for electromechanical damping. Two types of electrodes may be used—rectangular or non-rectangular—with a gap between them directed at some angle, usually 45°. The frequency bandwidth is wider (up to 9 kHz in the case of non-rectangular electrodes. The strip-like acoustic matching element bonded to the tip of the PMN-32%PT crystal may significantly enhance the performance of the ultrasonic receiver. It was proposed to use for this purpose AIREX T10.110 rigid polymer foam, the acoustic impedance of which is close to the optimal value necessary for matching with air. It was

Fast ultrasonic visualisation under sodium. Application to the fast neutron reactors

International Nuclear Information System (INIS)

Imbert, Ch.

1997-01-01

The fast ultrasonic visualization under sodium is in the programme of research and development on the inspection inside the fast neutron reactors. This work is about the development of a such system of fast ultrasonic imaging under sodium, in order to improve the existing visualization systems. This system is based on the principle of orthogonal imaging, it uses two linear antennas with an important dephasing having 128 piezo-composite elements of central frequency equal to 1.6 MHz. (N.C.)

Compressed Sensing Techniques Applied to Ultrasonic Imaging of Cargo Containers

Directory of Open Access Journals (Sweden)

Yuri Álvarez López

2017-01-01

Full Text Available One of the key issues in the fight against the smuggling of goods has been the development of scanners for cargo inspection. X-ray-based radiographic system scanners are the most developed sensing modality. However, they are costly and use bulky sources that emit hazardous, ionizing radiation. Aiming to improve the probability of threat detection, an ultrasonic-based technique, capable of detecting the footprint of metallic containers or compartments concealed within the metallic structure of the inspected cargo, has been proposed. The system consists of an array of acoustic transceivers that is attached to the metallic structure-under-inspection, creating a guided acoustic Lamb wave. Reflections due to discontinuities are detected in the images, provided by an imaging algorithm. Taking into consideration that the majority of those images are sparse, this contribution analyzes the application of Compressed Sensing (CS techniques in order to reduce the amount of measurements needed, thus achieving faster scanning, without compromising the detection capabilities of the system. A parametric study of the image quality, as a function of the samples needed in spatial and frequency domains, is presented, as well as the dependence on the sampling pattern. For this purpose, realistic cargo inspection scenarios have been simulated.

Development of high frequency tungsten inert gas welding method

International Nuclear Information System (INIS)

Morisada, Yoshiaki; Fujii, Hidetoshi; Inagaki, Fuminori; Kamai, Masayoshi

2013-01-01

Highlights: ► A new ultrasonic wave TIG welding method was developed. ► The area of the blowholes decreased to less than about 1/8 in the normal TIG weld. ► The number of blowholes decreased with the decreasing frequency. ► The number of blowholes increased when the frequency was less than 15 kHz. ► The microstructure of the weld was refined by ultrasonic wave. -- Abstract: A new welding method, called high frequency tungsten inert gas (TIG) welding, was developed to decrease blowholes in a weld. A1050 aluminum alloy plates (100 mm l × 50 mm w × 5 mm t ) were welded at a frequency from 10 to 40 kHz. An Ar-1% hydrogen mixture was used as the shielding gas to generate blowholes in the experiments. The welding was performed in the horizontal position so that the blowholes can easily be a problem. For comparison, a normal TIG welding was also performed at 60 Hz. After welding, the distribution of the blowholes in the welds was observed in order to evaluate the effect of the sonic wave. The number of blowholes changed with the frequency. A frequency near 15 kHz is the most suitable to decrease the blowholes. Using this new method, the area of blowholes is decreased to less than about 1/8 of the normal TIG weld. This method is much more effective for decreasing the number of blowholes, compared with an ultrasonic wave vibrator which is directly fixed to the sample.

Inverse method for effects characterization from ultrasonic b-scan images

International Nuclear Information System (INIS)

Faur, M.

1999-02-01

In service inspections of French nuclear pressure water reactor vessels are carried out automatically in complete immersion from the inside by means of ultrasonic focused probes working in the pulse echo mode. Concern has been expressed about the capabilities of performing non destructive evaluation of the Outer Surface Defects (OSD), i.e. defects located in the vicinity of the outer surface of the inspected components. OSD are insonified by both a direct field that passes through the inner surface (water/steel) of the component containing the defect and a secondary field reflected from the outer surface. Consequently, the Bscan images, containing the signatures of such defects, are complicated and their interpretation is a difficult task. This work deals with extraction of the maximum available information for characterizing OSD from ultrasonic Bscan images. Our main objectives are to obtain the type of OSD and their geometric parameters by means of two specific inverse methods. The first method is used for the identification of the geometrical parameters of the equivalent planar OSD from segmented Bscan images. Ultrasonic equivalent defect sizing model-based methods may be used to size a defect in a material by obtaining a best-fit simple equivalent shape that matches the ultrasonic observed data. We illustrate the application of such an equivalent sizing OSD method that is based on a simplified direct model. The major drawback of this identification method, as used to date, is that only a part of the useful information contained into original Bscan image, i.e. segmented Bscan image, is used for defect characterization. Moreover, it requires the availability of defect classification information (i.e. if the defect is volumetric or planer, e. g. a crack or a lack of fusion), which, generally, may be as difficult to obtain as the defect parameters themselves. Therefore, we propose a parameter estimation method for extracting complementary information on the defect

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

Directory of Open Access Journals (Sweden)

Yan Chen

2014-07-01

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

Ultrasonic phased array with surface acoustic wave for imaging cracks

Directory of Open Access Journals (Sweden)

Yoshikazu Ohara

2017-06-01

Full Text Available To accurately measure crack lengths, we developed a real-time surface imaging method (SAW PA combining an ultrasonic phased array (PA with a surface acoustic wave (SAW. SAW PA using a Rayleigh wave with a high sensitivity to surface defects was implemented for contact testing using a wedge with the third critical angle that allows the Rayleigh wave to be generated. Here, to realize high sensitivity imaging, SAW PA was optimized in terms of the wedge and the imaging area. The improved SAW PA was experimentally demonstrated using a fatigue crack specimen made of an aluminum alloy. For further verification in more realistic specimens, SAW PA was applied to stainless-steel specimens with a fatigue crack and stress corrosion cracks (SCCs. The fatigue crack was visualized with a high signal-to-noise ratio (SNR and its length was measured with a high accuracy of better than 1 mm. The SCCs generated in the heat-affected zones (HAZs of a weld were successfully visualized with a satisfactory SNR, although responses at coarse grains appeared throughout the imaging area. The SCC lengths were accurately measured. The imaging results also precisely showed complicated distributions of SCCs, which were in excellent agreement with the optically observed distributions.

Miniaturized and general purpose fiber optic ultrasonic sources

International Nuclear Information System (INIS)

Biagi, E.; Fontani, S.; Masotti, L.; Pieraccini, M.

1997-01-01

Innovative photoacoustic sources for ultrasonic NDE, smart structure, and clinical diagnosis are proposed. The working principle is based on thermal conversion of laser pulses into a metallic film evaporated directly onto the tip of a fiber optic. Unique features of the proposed transducers are very high miniaturization and potential easy embedding in smart structure. Additional advantages, high bedding in smart structure. Additional advantages, high ultrasonic frequency, large and flat bandwidth. All these characteristics make the proposed device an ideal ultrasonic source

Statistical physics of medical ultrasonic images

International Nuclear Information System (INIS)

Wagner, R.F.; Insana, M.F.; Brown, D.G.; Smith, S.W.

1987-01-01

The physical and statistical properties of backscattered signals in medical ultrasonic imaging are reviewed in terms of: 1) the radiofrequency signal; 2) the envelope (video or magnitude) signal; and 3) the density of samples in simple and in compounded images. There is a wealth of physical information in backscattered signals in medical ultrasound. This information is contained in the radiofrequency spectrum - which is not typically displayed to the viewer - as well as in the higher statistical moments of the envelope or video signal - which are not readily accessed by the human viewer of typical B-scans. This information may be extracted from the detected backscattered signals by straightforward signal processing techniques at low resolution

Head Injury and Intracranial Pressure Monitor Using Ultrasonic and Low-Frequency Acoustic (ULFA) Detection

National Research Council Canada - National Science Library

Vo-Dinh, Tuan

2001-01-01

The main objective of this research project is the development of a non-invasive method and instrument for head injury detection and monitoring using a new approach based on ultrasonic and low-frequency acoustic (ULFA...

Anomalous effect of high-frequency ultrasound on radiation diffraction in deformed single crystals

International Nuclear Information System (INIS)

Iolin, E.M.; Rajtman, Eh.A.; Kuvaldin, B.V.; Zolotoyabko, Eh.V.

1988-01-01

Results are presented of a theoretical and experimental study of neutron and X-ray diffraction in defromed single crystals on high-frequency ultrasonic excitation. It is demonstrated theoretically that at a frequency exceeding a certain threshold value the ultrasound violates the adiabatic conditions for the excitation point motion on the dispersion surface branches. This leads to an anomalous (compared to diffraction for a perfect crystal) dependence of the diffraction intensity on the ultrasonic wave amplitude. The experimental data for Si crystals are in good agreement with the theoretical predictions

Study of the influence of micro-structures and porosity of pellets alumina in the ultrasonic pulse in the frequency domain

International Nuclear Information System (INIS)

Costa, Antonio Mario Leal Martins

2009-01-01

This work is part of a study to the applicability of ultrasonic technique in the frequency domain for non-destructive characterization of ceramic pellets fuel, which is of great interest because of concern about the safety and efficacy in the nuclear industry. In this work it was analysed if there were changes in frequency spectrum, generated by the traveling of an ultrasonic pulse through ceramic pellets of aluminum oxide (Al 2 O 3 ). Using the ultrasonic technique in the frequency domain, together with micro-structural analysis of pellets by scanning electron microscope, it was possible to associate the characteristics of the material inspected with its respective frequency spectrum. The characterization was performed on 40 pellets alumina sintered in the temperatures of 1150, 1400, 1480, 1540 and 1580 deg C with porosities, as measured by the Archimedes method, ranging from 5.09% to 37.3%. The results show that the ultrasonic technique is effective in determining the micro-structure of ceramic alumina pellets and can be applied in the characterization of other porous materials in a production line, where the format of the frequency spectrum generated by the structure of the material may determine if the pellets belong the required specifications. (author)

Ultrasonic Stir Welding

Science.gov (United States)

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.

A fractional Fourier transform analysis of the scattering of ultrasonic waves

Science.gov (United States)

Tant, Katherine M.M.; Mulholland, Anthony J.; Langer, Matthias; Gachagan, Anthony

2015-01-01

Many safety critical structures, such as those found in nuclear plants, oil pipelines and in the aerospace industry, rely on key components that are constructed from heterogeneous materials. Ultrasonic non-destructive testing (NDT) uses high-frequency mechanical waves to inspect these parts, ensuring they operate reliably without compromising their integrity. It is possible to employ mathematical models to develop a deeper understanding of the acquired ultrasonic data and enhance defect imaging algorithms. In this paper, a model for the scattering of ultrasonic waves by a crack is derived in the time–frequency domain. The fractional Fourier transform (FrFT) is applied to an inhomogeneous wave equation where the forcing function is prescribed as a linear chirp, modulated by a Gaussian envelope. The homogeneous solution is found via the Born approximation which encapsulates information regarding the flaw geometry. The inhomogeneous solution is obtained via the inverse Fourier transform of a Gaussian-windowed linear chirp excitation. It is observed that, although the scattering profile of the flaw does not change, it is amplified. Thus, the theory demonstrates the enhanced signal-to-noise ratio permitted by the use of coded excitation, as well as establishing a time–frequency domain framework to assist in flaw identification and classification. PMID:25792967

High-precision terahertz frequency modulated continuous wave imaging method using continuous wavelet transform

Science.gov (United States)

Zhou, Yu; Wang, Tianyi; Dai, Bing; Li, Wenjun; Wang, Wei; You, Chengwu; Wang, Kejia; Liu, Jinsong; Wang, Shenglie; Yang, Zhengang

2018-02-01

Inspired by the extensive application of terahertz (THz) imaging technologies in the field of aerospace, we exploit a THz frequency modulated continuous-wave imaging method with continuous wavelet transform (CWT) algorithm to detect a multilayer heat shield made of special materials. This method uses the frequency modulation continuous-wave system to catch the reflected THz signal and then process the image data by the CWT with different basis functions. By calculating the sizes of the defects area in the final images and then comparing the results with real samples, a practical high-precision THz imaging method is demonstrated. Our method can be an effective tool for the THz nondestructive testing of composites, drugs, and some cultural heritages.

Internal ultrasonic inspection of flexible pipe

Energy Technology Data Exchange (ETDEWEB)

Baltzersen, O. (IKU Petroleumsforskning A/S, Trondheim (Norway) Norwegian Inst. of Tech., Trondheim (Norway). Div. of Petroleum Engineering and Applied Geophysics); Waag, T.I. (IKU Petroleumsforskning A/S, Trondheim (Norway))

1993-10-01

Methods for internal ultrasonic inspection of flexible pipe have been investigated through experiments with a short sample of Coflexip pipe. Ultrasonic backscatter methods using normal and non-normal incidence have been used for qualitative high contrast ultrasonic imaging of the inner surface of the pipe. Analysis of the internal cross-section has been performed based on the use of a non-contact ultrasonic caliper, and processing procedures which enable calculation of, and compensation for, eccentricity of the tool in the pipe. The methods developed can be used to quantitatively estimate the thickness of the internal carcass, and perform high resolution topographic mapping of the inner surface. (Author)

Edge Detection from High Resolution Remote Sensing Images using Two-Dimensional log Gabor Filter in Frequency Domain

International Nuclear Information System (INIS)

Wang, K; Yu, T; Meng, Q Y; Wang, G K; Li, S P; Liu, S H

2014-01-01

Edges are vital features to describe the structural information of images, especially high spatial resolution remote sensing images. Edge features can be used to define the boundaries between different ground objects in high spatial resolution remote sensing images. Thus edge detection is important in the remote sensing image processing. Even though many different edge detection algorithms have been proposed, it is difficult to extract the edge features from high spatial resolution remote sensing image including complex ground objects. This paper introduces a novel method to detect edges from the high spatial resolution remote sensing image based on frequency domain. Firstly, the high spatial resolution remote sensing images are Fourier transformed to obtain the magnitude spectrum image (frequency image) by FFT. Then, the frequency spectrum is analyzed by using the radius and angle sampling. Finally, two-dimensional log Gabor filter with optimal parameters is designed according to the result of spectrum analysis. Finally, dot product between the result of Fourier transform and the log Gabor filter is inverse Fourier transformed to obtain the detections. The experimental result shows that the proposed algorithm can detect edge features from the high resolution remote sensing image commendably

Guided-wave tomography imaging plate defects by laser-based ultrasonic techniques

Energy Technology Data Exchange (ETDEWEB)

Park, Jun Pil; Lim, Ju Young; Cho, Youn Ho [School of Mechanical Engineering, Pusan National University, Pusan (Korea, Republic of)

2014-12-15

Contact-guided-wave tests are impractical for investigating specimens with limited accessibility and rough surfaces or complex geometric features. A non-contact setup with a laser-ultrasonic transmitter and receiver is quite attractive for guided-wave inspection. In the present work, we developed a non-contact guided-wave tomography technique using the laser-ultrasonic technique in a plate. A method for Lamb-wave generation and detection in an aluminum plate with a pulsed laser-ultrasonic transmitter and Michelson-interferometer receiver was developed. The defect shape and area in the images obtained using laser scanning, showed good agreement with the actual defect. The proposed approach can be used as a non-contact online inspection and monitoring technique.

A New High-Temperature Ultrasonic Transducer for Continuous Inspection.

Science.gov (United States)

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

2016-03-01

A novel design of piezoelectric ultrasonic transducer is introduced, suitable for operation at temperatures of up to 700 °C-800 °C. Lithium niobate single crystal is chosen as the piezoelectric element primarily due to the high Curie temperature of 1200 °C. A backing element based on a porous ceramic is designed for which the pore volume fraction and average pore diameter in the ceramic matrix can be controlled in the manufacturing process; this enables the acoustic impedance and attenuation to be selected to match their optimal values as predicted by a one-dimensional transducer model of the entire transducer. Porous zirconia is selected as the ceramic matrix material of the backing element to obtain an ultrasonic signal with center frequency of 2.7-3 MHz, and 3-dB bandwidth of 90%-95% at the targeted operating temperature. Acoustic coupling of the piezocrystal to the backing element and matching layer is investigated using commercially available high-temperature adhesives and brazing alloys. The performance of the transducer as a function of temperature is studied. Stable bonding and clear signals were obtained using an aluminum brazing alloy as the bonding agent.

Ultrasonic analysis of UO{sub 2} pellets

Energy Technology Data Exchange (ETDEWEB)

Bittencourt, Marcelo de S.Q.; Baroni, Douglas B.; Martorelli, Daniel S., E-mail: bittenc@ien.gov.br, E-mail: douglasbaroni@ien.gov.br, E-mail: daniel@ien.gov.br [Instituto de Engenharia Nuclear (IEN/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Lab. de Ultrassom; Dias, Fabio C.; Silva, Jose W.S. da, E-mail: fabio@ird.gov.br, E-mail: wanderley@ird.gov.br [Instituto de Radioprotecao e Dosimetria (IRD/CNEN-RJ), Rio de Janeiro, RJ (Brazil). Lab. de Salvaguardas

2013-07-01

Ceramic materials have been widely used for various purposes in many different industries due to certain characteristics, such as high melting point and high resistance to corrosion. In the nuclear area, ceramics are of great importance due to the process of fabrication of fuel pellets for nuclear reactors. Generally, high accuracy destructive techniques are used to characterize nuclear materials for fuel fabrication. These techniques usually require costly equipment and facilities, as well as experienced personnel. This paper aims at presenting an analysis methodology for UO2 pellets using a non-destructive ultrasonic technique for porosity measurement. This technique differs from traditional ultrasonic techniques in the sense it uses ultrasonic pulses in frequency domain instead of time domain. Therefore, specific characteristics of the analyzed material are associated with the obtained frequency spectrum. In the present work, four fuel grade UO2 pellets were analyzed and the corresponding results evaluated. (author)

Separated reconstruction of images from ultrasonic holograms with tridimensional object by digital processing

International Nuclear Information System (INIS)

Son, J.H.

1979-01-01

Because of much attractiveness, digital reconstruction of image from ultrasonic hologram by computer has been widely studied in recent years. But the method of digital reconstruction of image is displayed in the plain only, so study is done mainly of the hologram obtained from bidimensional objects. Many applications of the ultrasonic holography such as the non-distructive testing and the ultrasonic diagnosis are mostly of the tridimensional object. In the ordinary digital reconstruction of the image from the hologram obtained from tridimensional object, a question of hidden-image problem arises, and the separated reconstruction of the image for the considered part of the object is required. In this paper, multi-diffraction by tridimensional object is assumed to have linearity, ie. superposition property by each diffraction of bidimensional objects. And a new algorithm is proposed here, namely reconstructed image for considered one of bidimensional objects in tridimensional object obtained by means of operation from the two holograms tilted in unequal angles. Such tilted holograms are obtained from the tilted linear array receivers by scanning method. That images can be reconstructed by the operation from two holograms means that the new algorithm is verified. And another new method of the transformation of hologram, that is, transformation of a hologram to arbitrarily tilted hologram, has been proved valid. The reconstructed images obtained with the method of transformation and the method of operation, are the images reconstructed from one hologram by the tridimensional object and more distinctly separated that any images mentioned above. (author)

Sampling phased array a new technique for signal processing and ultrasonic imaging

OpenAIRE

Bulavinov, A.; Joneit, D.; Kröning, M.; Bernus, L.; Dalichow, M.H.; Reddy, K.M.

2006-01-01

Different signal processing and image reconstruction techniques are applied in ultrasonic non-destructive material evaluation. In recent years, rapid development in the fields of microelectronics and computer engineering lead to wide application of phased array systems. A new phased array technique, called "Sampling Phased Array" has been developed in Fraunhofer Institute for non-destructive testing. It realizes unique approach of measurement and processing of ultrasonic signals. The sampling...

Segmentation methodology for automated classification and differentiation of soft tissues in multiband images of high-resolution ultrasonic transmission tomography.

Science.gov (United States)

Jeong, Jeong-Won; Shin, Dae C; Do, Synho; Marmarelis, Vasilis Z

2006-08-01

This paper presents a novel segmentation methodology for automated classification and differentiation of soft tissues using multiband data obtained with the newly developed system of high-resolution ultrasonic transmission tomography (HUTT) for imaging biological organs. This methodology extends and combines two existing approaches: the L-level set active contour (AC) segmentation approach and the agglomerative hierarchical kappa-means approach for unsupervised clustering (UC). To prevent the trapping of the current iterative minimization AC algorithm in a local minimum, we introduce a multiresolution approach that applies the level set functions at successively increasing resolutions of the image data. The resulting AC clusters are subsequently rearranged by the UC algorithm that seeks the optimal set of clusters yielding the minimum within-cluster distances in the feature space. The presented results from Monte Carlo simulations and experimental animal-tissue data demonstrate that the proposed methodology outperforms other existing methods without depending on heuristic parameters and provides a reliable means for soft tissue differentiation in HUTT images.

High frequency/ultrasonic communication in a critically endangered nocturnal primate, Claire's mouse lemur (Microcebus mamiratra).

Science.gov (United States)

Hasiniaina, Alida F; Scheumann, Marina; Rina Evasoa, Mamy; Braud, Diane; Rasoloharijaona, Solofonirina; Randrianambinina, Blanchard; Zimmermann, Elke

2018-05-02

The critically endangered Claire's mouse lemur, only found in the evergreen rain forest of the National Park Lokobe (LNP) and a few lowland evergreen rain forest fragments of northern Madagascar, was described recently. The present study provides the first quantified information on vocal acoustics of calls, sound associated behavioral context, acoustic niche, and vocal activity of this species. We recorded vocal and social behavior of six male-female and six male-male dyads in a standardized social-encounter paradigm in June and July 2016 at the LNP, Nosy Bé island. Over six successive nights per dyad, we audio recorded and observed behaviors for 3 hr at the beginning of the activity period. Based on the visual inspection of spectrograms and standardized multiparametric sound analysis, we identified seven different call types. Call types can be discriminated based on a combination of harmonicity, fundamental frequency variation, call duration, and degree of tonality. Acoustic features of tonal call types showed that for communication, mouse lemurs use the cryptic, high frequency/ultrasonic frequency niche. Two call types, the Tsak and the Grunt call, were emitted most frequently. Significant differences in vocal activity of the Tsak call were found between male-female and male-male dyads, linked primarily to agonistic conflicts. Dominant mouse lemurs vocalized more than subdominant ones, suggesting that signaling may present an honest indicator of fitness. A comparison of our findings of the Claire's mouse lemur with published findings of five bioacoustically studied mouse lemur species points to the notion that a complex interplay between ecology, predation pressure, and phylogenetic relatedness may shape the evolution of acoustic divergence between species in this smallest-bodied primate radiation. Thus, comparative bioacoustic studies, using standardized procedures, are promising to unravel the role of vocalization for primate species diversity and evolution

Remote consulting based on ultrasonic digital immages and dynamic ultrasonic sequences

Science.gov (United States)

Margan, Anamarija; Rustemović, Nadan

2006-03-01

Telematic ultrasonic diagnostics is a relatively new tool in providing health care to patients in remote, islolated communities. Our project facility, "The Virtual Polyclinic - A Specialists' Consulting Network for the Islands", is located on the island of Cres in the Adriatic Sea in Croatia and has been extending telemedical services to the archipelago population since 2000. Telemedicine applications include consulting services by specialists at the University Clinical Hospital Center Rebro in Zagreb and at "Magdalena", a leading cardiology clinic in Croatia. After several years of experience with static high resolution ultrasonic digital immages for referral consulting diagnostics purposes, we now also use dynamic ultrasonic sequences in a project with the Department of Emmergency Gastroenterology at Rebro in Zagreb. The aim of the ongoing project is to compare the advantages and shortcomings in transmitting static ultrasonic digital immages and live sequences of ultrasonic examination in telematic diagnostics. Ultrasonic examination is a dynamic process in which the diagnostic accuracy is highly dependent on the dynamic moment of an ultrasound probe and signal. Our first results indicate that in diffuse parenchymal organ pathology the progression and the follow up of a disease is better presented to a remote consulting specialist by dynamic ultrasound sequences. However, the changes that involve only one part of a parenchymal organ can be suitably presented by static ultrasonic digital images alone. Furthermore, we need less time for digital imaging and such tele-consultations overall are more economical. Our previous telemedicine research and practice proved that we can greatly improve the level of medical care in remote healthcare facilities and cut healthcare costs considerably. The experience in the ongoing project points to a conclusion that we can further optimize remote diagnostics benefits by a right choice of telematic application thus reaching a

Ultrasonic flow-through filtration of microparticles in a microfluidic channel using frequency sweep technique

International Nuclear Information System (INIS)

Seo, Dae Cheol; Ahn, Bong Young; Cho, Seung Hyun; Siddique, A. K. M. Ariful Haque; Kim, Cheol Gi

2013-01-01

Many studies have been conducted on the filtration of microparticles using the acoustic radiation force of ultrasonic standing wave. The present work concerns a flow-through particle filtration method by utilizing frequency varying ultrasound. The periodical frequency sweep of the ultrasonic standing wave translocates particles across a microchannel, where particles in fluid flow are filtrated without barriers. The present filtration technique in a microfluidic channel was proposed conceptually in the 1990s. However, its experimental realization on actual particles in a microfluidic channel has not been carried out in a notable way. Several sizes of polystyrene microspheres (10 µm to 90 µm) and silicon carbide (SiC) particles (37 µm) suspended in water were applied as a test sample. For filtration of those particles, a Y-branched microfluidic channel with one inlet and two outlets was made out of steel and acrylic as a form of modulized device. Ultrasound of a few MHz in band frequency (1.75 MHz to 3.05 MHz) was transmitted into one side of the channel wall to generate a standing wave field in fluid flow. The periodical frequency sweep operation showed successful filtration performance, whereby particles in water flowed into one outlet and purified water flowed into the other outlet of the Y branch of the channel.

Non-contact feature detection using ultrasonic Lamb waves

Science.gov (United States)

Sinha, Dipen N [Los Alamos, NM

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.

Background Noise Removal in Ultrasonic B-scan Images Using Iterative Statistical Techniques

NARCIS (Netherlands)

Wells, I.; Charlton, P. C.; Mosey, S.; Donne, K. E.

2008-01-01

The interpretation of ultrasonic B-scan images can be a time-consuming process and its success depends on operator skills and experience. Removal of the image background will potentially improve its quality and hence improve operator diagnosis. An automatic background noise removal algorithm is

Sampling phased array - a new technique for ultrasonic signal processing and imaging

OpenAIRE

Verkooijen, J.; Boulavinov, A.

2008-01-01

Over the past 10 years, the improvement in the field of microelectronics and computer engineering has led to significant advances in ultrasonic signal processing and image construction techniques that are currently being applied to non-destructive material evaluation. A new phased array technique, called 'Sampling Phased Array', has been developed in the Fraunhofer Institute for Non-Destructive Testing([1]). It realises a unique approach of measurement and processing of ultrasonic signals. Th...

Effects of frequency and a radical scavenger on ultrasonic degradation of water-soluble polymers.

Science.gov (United States)

Koda, Shinobu; Taguchi, Kimihiko; Futamura, Kazunori

2011-01-01

Ultrasonic degradation of methyl cellulose, pullulan, dextran and poly(ethylene oxide) in aqueous solutions was investigated at the frequencies of 20 and 500 kHz, where the ultrasonic power delivered into solutions was kept constant (22 W). The number average molecular mass and the polydispersity were obtained as a function of sonication time. The degradation under sonication at the 500 kHz frequency proceeded faster in comparison with the 20 kHz sonication for four polymers. The addition of a radical scavenger, t-BuOH, resulted in suppression of degradation of water-soluble polymers. The degradation rate constants were estimated from the plot of molecular weight against sonication time. The degradation rate of methyl cellulose was the largest one among the investigated polymers. The difference in the degradation rates was discussed in terms of the flexibility and the hydrodynamic radius of polymer chains in aqueous solutions. Copyright © 2010 Elsevier B.V. All rights reserved.

High frequency guided wave propagation in monocrystalline silicon wafers

OpenAIRE

Pizzolato, M.; Masserey, B.; Robyr, J. L.; Fromme, P.

2017-01-01

Monocrystalline silicon wafers are widely used in the photovoltaic industry for solar panels with high conversion efficiency. The cutting process can introduce micro-cracks in the thin wafers and lead to varying thickness. High frequency guided ultrasonic waves are considered for the structural monitoring of the wafers. The anisotropy of the monocrystalline silicon leads to variations of the wave characteristics, depending on the propagation direction relative to the crystal orientation. Full...

Guided-wave tomographic imaging of plate defects by laser-based ultrasonic techniques

Energy Technology Data Exchange (ETDEWEB)

Park, Junpil; Lim, Ju Young; Cho, Youn Ho [School of Mechanical Engineering, Pusan National University, Busan (Korea, Republic of)

2016-12-15

Contact-guided-wave tests are impractical for investigating specimens with limited accessibility and rough surfaces or complex geometric features. A non-contact setup with a laser-ultrasonic transmitter and receiver is quite attractive for guided-wave inspection. In the present work, we developed a non-contact guided-wave tomography technique using the laser-ultrasonic technique in a plate. A method for Lamb-wave generation and detection in an aluminum plate with a pulsed laser-ultrasonic transmitter and Michelson-interferometer receiver was developed. The defect shape and area in the images obtained using laser scanning, showed good agreement with the actual defect. The proposed approach can be used as a non-contact online inspection and monitoring technique.

Development of computer-controlled ultrasonic image processing system for severe accidents research

International Nuclear Information System (INIS)

Koo, Kil Mo; Kang, Kyung Ho; Kim, Jong Tai; Kim, Jong Whan; Cho, Young Ro; Ha, Kwang Soon; Park, Rae Jun; Kim, Sang Baik; Kim, Hee Dong; Sim, Chul Moo

2000-07-01

In order to verify in-vessel corium cooling mechanism, LAVA(Lower-plenum Arrested Vessel Attack) experiment is being performed as a first stage proof of principle test. The aims of this study are to find a gap formation between corium melt and reactor lower head vessel, to verify the principle of the gap formation and to analyze the effect of the gap formation on the thermal behavior of corium melt and the lower plenum. This report aims at developing a computer controlled image signal processing system which is able to improve visualization and to measure the gap distribution with 3-dimensional planar image using a time domain signal analysis method as a part of the ultrasonic pulse echo methods and a computerized position control system. An image signal processing system is developed by independently developing an ultrasonic image signal processing technique and a PC controlled position control system and then combining both systems

Development of computer-controlled ultrasonic image processing system for severe accidents research

Energy Technology Data Exchange (ETDEWEB)

Koo, Kil Mo; Kang, Kyung Ho; Kim, Jong Tai; Kim, Jong Whan; Cho, Young Ro; Ha, Kwang Soon; Park, Rae Jun; Kim, Sang Baik; Kim, Hee Dong; Sim, Chul Moo

2000-07-01

In order to verify in-vessel corium cooling mechanism, LAVA(Lower-plenum Arrested Vessel Attack) experiment is being performed as a first stage proof of principle test. The aims of this study are to find a gap formation between corium melt and reactor lower head vessel, to verify the principle of the gap formation and to analyze the effect of the gap formation on the thermal behavior of corium melt and the lower plenum. This report aims at developing a computer controlled image signal processing system which is able to improve visualization and to measure the gap distribution with 3-dimensional planar image using a time domain signal analysis method as a part of the ultrasonic pulse echo methods and a computerized position control system. An image signal processing system is developed by independently developing an ultrasonic image signal processing technique and a PC controlled position control system and then combining both systems.

Material State Awareness for Composites Part II: Precursor Damage Analysis and Quantification of Degraded Material Properties Using Quantitative Ultrasonic Image Correlation (QUIC)

Science.gov (United States)

Patra, Subir; Banerjee, Sourav

2017-01-01

Material state awareness of composites using conventional Nondestructive Evaluation (NDE) method is limited by finding the size and the locations of the cracks and the delamination in a composite structure. To aid the progressive failure models using the slow growth criteria, the awareness of the precursor damage state and quantification of the degraded material properties is necessary, which is challenging using the current NDE methods. To quantify the material state, a new offline NDE method is reported herein. The new method named Quantitative Ultrasonic Image Correlation (QUIC) is devised, where the concept of microcontinuum mechanics is hybrid with the experimentally measured Ultrasonic wave parameters. This unique combination resulted in a parameter called Nonlocal Damage Entropy for the precursor awareness. High frequency (more than 25 MHz) scanning acoustic microscopy is employed for the proposed QUIC. Eight woven carbon-fiber-reinforced-plastic composite specimens were tested under fatigue up to 70% of their remaining useful life. During the first 30% of the life, the proposed nonlocal damage entropy is plotted to demonstrate the degradation of the material properties via awareness of the precursor damage state. Visual proofs for the precursor damage states are provided with the digital images obtained from the micro-optical microscopy, the scanning acoustic microscopy and the scanning electron microscopy. PMID:29258256

Material State Awareness for Composites Part II: Precursor Damage Analysis and Quantification of Degraded Material Properties Using Quantitative Ultrasonic Image Correlation (QUIC

Directory of Open Access Journals (Sweden)

Subir Patra

2017-12-01

Full Text Available Material state awareness of composites using conventional Nondestructive Evaluation (NDE method is limited by finding the size and the locations of the cracks and the delamination in a composite structure. To aid the progressive failure models using the slow growth criteria, the awareness of the precursor damage state and quantification of the degraded material properties is necessary, which is challenging using the current NDE methods. To quantify the material state, a new offline NDE method is reported herein. The new method named Quantitative Ultrasonic Image Correlation (QUIC is devised, where the concept of microcontinuum mechanics is hybrid with the experimentally measured Ultrasonic wave parameters. This unique combination resulted in a parameter called Nonlocal Damage Entropy for the precursor awareness. High frequency (more than 25 MHz scanning acoustic microscopy is employed for the proposed QUIC. Eight woven carbon-fiber-reinforced-plastic composite specimens were tested under fatigue up to 70% of their remaining useful life. During the first 30% of the life, the proposed nonlocal damage entropy is plotted to demonstrate the degradation of the material properties via awareness of the precursor damage state. Visual proofs for the precursor damage states are provided with the digital images obtained from the micro-optical microscopy, the scanning acoustic microscopy and the scanning electron microscopy.

Crossed SMPS MOSFET-based protection circuit for high frequency ultrasound transceivers and transducers.

Science.gov (United States)

Choi, Hojong; Shung, K Kirk

2014-06-12

The ultrasonic transducer is one of the core components of ultrasound systems, and the transducer's sensitivity is significantly related the loss of electronic components such as the transmitter, receiver, and protection circuit. In an ultrasonic device, protection circuits are commonly used to isolate the electrical noise between an ultrasound transmitter and transducer and to minimize unwanted discharged pulses in order to protect the ultrasound receiver. However, the performance of the protection circuit and transceiver obviously degrade as the operating frequency or voltage increases. We therefore developed a crossed SMPS (Switching Mode Power Supply) MOSFET-based protection circuit in order to maximize the sensitivity of high frequency transducers in ultrasound systems.The high frequency pulse signals need to trigger the transducer, and high frequency pulse signals must be received by the transducer. We therefore selected the SMPS MOSFET, which is the main component of the protection circuit, to minimize the loss in high frequency operation. The crossed configuration of the protection circuit can drive balanced bipolar high voltage signals from the pulser and transfer the balanced low voltage echo signals from the transducer. The equivalent circuit models of the SMPS MOSFET-based protection circuit are shown in order to select the proper device components. The schematic diagram and operation mechanism of the protection circuit is provided to show how the protection circuit is constructed. The P-Spice circuit simulation was also performed in order to estimate the performance of the crossed MOSFET-based protection circuit. We compared the performance of our crossed SMPS MOSFET-based protection circuit with a commercial diode-based protection circuit. At 60 MHz, our expander and limiter circuits have lower insertion loss than the commercial diode-based circuits. The pulse-echo test is typical method to evaluate the sensitivity of ultrasonic transducers

Medium-high frequency ultrasound and ozone based advanced oxidation for amoxicillin removal in water.

Science.gov (United States)

Kıdak, Rana; Doğan, Şifa

2018-01-01

In this study, treatment of an antibiotic compound amoxicillin by medium-high frequency ultrasonic irradiation and/or ozonation has been studied. Ultrasonic irradiation process was carried out in a batch reactor for aqueous amoxicillin solutions at three different frequencies (575, 861 and 1141kHz). The applied ultrasonic power was 75W and the diffused power was calculated as 14.6W/L. The highest removal was achieved at 575kHz ultrasonic frequency (>99%) with the highest pseudo first order reaction rate constant 0.04min -1 at pH 10 but the mineralization achieved was around 10%. Presence of alkalinity and humic acid species had negative effect on the removal efficiency (50% decrease). To improve the poor outcomes, ozonation had been applied with or without ultrasound. Ozone removed the amoxicillin at a rate 50 times faster than ultrasound. Moreover, due to the synergistic effect, coupling of ozone and ultrasound gave rise to rate constant of 2.5min -1 (625 times higher than ultrasound). In the processes where ozone was used, humic acid did not show any significant effect because the rate constant was so high that ozone has easily overcome the scavenging effects of natural water constituents. Furthermore, the intermediate compounds, after the incomplete oxidation mechanisms, has been analyzed to reveal the possible degradation pathways of amoxicillin through ultrasonic irradiation and ozonation applications. The outcomes of the intermediate compounds experiments and the toxicity was investigated to give a clear explanation about the safety of the resulting solution. The relevance of all the results concluded that hybrid advanced oxidation system was the best option for amoxicillin removal. Copyright © 2017 Elsevier B.V. All rights reserved.

Microbubble Composition and Preparation for High-Frequency Contrast-Enhanced Ultrasound Imaging: In Vitro and in Vivo Evaluation

NARCIS (Netherlands)

V. Daeichin (Verya); T. van Rooij (Tom); I. Skachkov (Ilya); B. Ergin (Bulent); P. Specht (Patricia); A.A.P. Lima (Alexandre ); C. Ince (Can); J.G. Bosch (Hans); A.F.W. van der Steen (Ton); N. de Jong (Nico); K. Kooiman (Klazina)

2017-01-01

textabstractAlthough high-frequency ultrasound imaging is gaining attention in various applications, hardly any ultrasound contrast agents (UCAs) dedicated to such frequencies (>15 MHz) are available for contrast-enhanced ultrasound (CEUS) imaging. Moreover, the composition of the limited

High-resolution ultrasonic spectroscopy

Directory of Open Access Journals (Sweden)

V. Buckin

2018-03-01

Full Text Available High-resolution ultrasonic spectroscopy (HR-US is an analytical technique for direct and non-destructive monitoring of molecular and micro-structural transformations in liquids and semi-solid materials. It is based on precision measurements of ultrasonic velocity and attenuation in analysed samples. The application areas of HR-US in research, product development, and quality and process control include analysis of conformational transitions of polymers, ligand binding, molecular self-assembly and aggregation, crystallisation, gelation, characterisation of phase transitions and phase diagrams, and monitoring of chemical and biochemical reactions. The technique does not require optical markers or optical transparency. The HR-US measurements can be performed in small sample volumes (down to droplet size, over broad temperature range, at ambient and elevated pressures, and in various measuring regimes such as automatic temperature ramps, titrations and measurements in flow.

Ultrasonically Assisted Single Point Diamond Turning of Optical Mold of Tungsten Carbide

Directory of Open Access Journals (Sweden)

Zhanjie Li

2018-02-01

Full Text Available To realize high efficiency, low/no damage and high precision machining of tungsten carbide used for lens mold, a high frequency ultrasonic vibration cutting system was developed at first. Then, tungsten carbide was precisely machined with a polycrystalline diamond (PCD tool assisted by the self-developed high frequency ultrasonic vibration cutting system. Tool wear mechanism was investigated in ductile regime machining of tungsten carbide. The cutter back-off phenomenon in the process was analyzed. The subsequent experimental results of ultra-precision machining with a single crystal diamond tool showed that: under the condition of high frequency ultrasonic vibration cutting, nano-scale surface roughness can be obtained by the diamond tool with smaller tip radius and no defects like those of ground surface were found on the machined surface. Tool wear mechanisms of the single crystal diamond tool are mainly abrasive wear and micro-chipping. To solve the problem, a method of inclined ultrasonic vibration cutting with negative rake angle was put forward according to force analysis, which can further reduce tool wear and roughness of the machined surface. The investigation was important to high efficiency and quality ultra-precision machining of tungsten carbide.

Microbubble Composition and Preparation for High-Frequency Contrast-Enhanced Ultrasound Imaging : In Vitro and in Vivo Evaluation

NARCIS (Netherlands)

Daeichin, Verya; van Rooij, Tom; Skachkov, Ilya; Ergin, Bulent; Specht, Patricia A.C.; Lima, Alexandre; Ince, Can; Bosch, Johan G.; van der Steen, A.F.W.; de Jong, N.; Kooiman, Klazina

2017-01-01

Although high-frequency ultrasound imaging is gaining attention in various applications, hardly any ultrasound contrast agents (UCAs) dedicated to such frequencies (>15 MHz) are available for contrast-enhanced ultrasound (CEUS) imaging. Moreover, the composition of the limited commercially

Microbubble Composition and Preparation for High-Frequency Contrast-Enhanced Ultrasound Imaging: In Vitro and In Vivo Evaluation

NARCIS (Netherlands)

Daeichin, Verya; van Rooij, Tom; Skachkov, Ilya; Ergin, Bulent; Specht, Patricia A. C.; Lima, Alexandre; Ince, Can; Bosch, Johan G.; van der Steen, Antonius F. W.; de Jong, Nico; Kooiman, Klazina

2017-01-01

Although high-frequency ultrasound imaging is gaining attention in various applications, hardly any ultrasound contrast agents (UCAs) dedicated to such frequencies (>15 MHz) are available for contrast-enhanced ultrasound (CEUS) imaging. Moreover, the composition of the limited commercially available

Attached cavitation at a small diameter ultrasonic horn tip

Science.gov (United States)

Žnidarčič, Anton; Mettin, Robert; Cairós, Carlos; Dular, Matevž

2014-02-01

Ultrasonic horn transducers are frequently used in applications of acoustic cavitation in liquids, for instance, for cell disruption or sonochemical reactions. They are operated typically in the frequency range up to about 50 kHz and have tip diameters from some mm to several cm. It has been observed that if the horn tip is sufficiently small and driven at high amplitude, cavitation is very strong, and the tip can be covered entirely by the gas/vapor phase for longer time intervals. A peculiar dynamics of the attached cavity can emerge with expansion and collapse at a self-generated frequency in the subharmonic range, i.e., below the acoustic driving frequency. Here, we present a systematic study of the cavitation dynamics in water at a 20 kHz horn tip of 3 mm diameter. The system was investigated by high-speed imaging with simultaneous recording of the acoustic emissions. Measurements were performed under variation of acoustic power, air saturation, viscosity, surface tension, and temperature of the liquid. Our findings show that the liquid properties play no significant role in the dynamics of the attached cavitation at the small ultrasonic horn. Also the variation of the experimental geometry, within a certain range, did not change the dynamics. We believe that the main two reasons for the peculiar dynamics of cavitation on a small ultrasonic horn are the higher energy density on a small tip and the inability of the big tip to "wash" away the gaseous bubbles. Calculation of the somewhat adapted Strouhal number revealed that, similar to the hydrodynamic cavitation, values which are relatively low characterize slow cavitation structure dynamics. In cases where the cavitation follows the driving frequency this value lies much higher - probably at Str > 20. In the spirit to distinguish the observed phenomenon with other cavitation dynamics at ultrasonic transducer surfaces, we suggest to term the observed phenomenon of attached cavities partly covering the full horn

Damage detection in composites using nonlinear ultrasonically modulated thermography

Science.gov (United States)

Malfense Fierro, G.-P.; Dionysopoulos, D.; Meo, M.; Ciampa, F.

2018-03-01

This paper proposes a novel nonlinear ultrasonically stimulated thermography technique for a quick and reliable assessment of material damage in carbon fibre reinforced plastic (CFRP) composite materials. The proposed nondestructive evaluation (NDE) method requires narrow sweep ultrasonic excitation using contact piezoelectric transducers in order to identify dual excitation frequencies associated with the damage resonance. High-amplitude signals and higher harmonic generation are necessary conditions for an accurate identification of these two input frequencies. Dual periodic excitation using high- and low-frequency input signals was then performed in order to generate frictional heating at the crack location that was measured by an infrared (IR) camera. To validate this concept, an impact damaged CFRP composite panel was tested and the experimental results were compared with traditional flash thermography. A laser vibrometer was used to investigate the response of the material with dual frequency excitation. The proposed nonlinear ultrasonically modulated thermography successfully detected barely visible impact damage in CFRP composites. Hence, it can be considered as an alternative to traditional flash thermography and thermosonics by allowing repeatable detection of damage in composites.

A New Low-frequency Sonophoresis System Combined with Ultrasonic Motor and Transducer

Science.gov (United States)

Zhu, Pancheng; Peng, Hanmin; Yang, Jianzhi; Mao, Ting; Sheng, Juan

2018-03-01

Low frequency sonophoresis (LFS) is currently being attempted as a transdermal drug delivery method in clinical areas. However, it lacks both an effective control method and the equipment to satisfy the varying drug dosage requirements of individual patients. Herein, a novel method aimed at controlling permeability is proposed and developed, using a pressure control strategy which is based on an accurate, adjustable and non-invasive ultrasound transdermal drug delivery system in in vitro LFS. The system mainly consists of a lead screw linear ultrasonic motor and an ultrasonic transducer, in which the former offers pressure and the latter provides ultrasound wave in the liquid. The ultrasound can enhance non-invasive permeation and the pressure from the motor can control the permeability. The calculated and experimental results demonstrate that the maximum pressure on artificial skin is under the area with the maximum vibration amplitude of the ultrasonic transducer, and the total pressure consists of acoustic pressure from the transducer and approximate static pressure from the motor. Changing the static pressure from the ultrasonic motor can effectively control the non-invasive permeability, by adjusting the duty ratio or the amplitude of the motor’s driving voltage. In addition, the permeability control of calcein by thrust control is realized in 15 min, indicating the suitability of this method for application in accurate medical technology. The obtained results reveal that the issue of difficult permeability control can be addressed, using this control method in in vitro LFS to open up a route to the design of accurate drug delivery technology for individual patients.

Characteristics of different frequency ranges in scanning electron microscope images

International Nuclear Information System (INIS)

Sim, K. S.; Nia, M. E.; Tan, T. L.; Tso, C. P.; Ee, C. S.

2015-01-01

We demonstrate a new approach to characterize the frequency range in general scanning electron microscope (SEM) images. First, pure frequency images are generated from low frequency to high frequency, and then, the magnification of each type of frequency image is implemented. By comparing the edge percentage of the SEM image to the self-generated frequency images, we can define the frequency ranges of the SEM images. Characterization of frequency ranges of SEM images benefits further processing and analysis of those SEM images, such as in noise filtering and contrast enhancement

Characteristics of different frequency ranges in scanning electron microscope images

Energy Technology Data Exchange (ETDEWEB)

Sim, K. S., E-mail: kssim@mmu.edu.my; Nia, M. E.; Tan, T. L.; Tso, C. P.; Ee, C. S. [Faculty of Engineering and Technology, Multimedia University, 75450 Melaka (Malaysia)

2015-07-22

We demonstrate a new approach to characterize the frequency range in general scanning electron microscope (SEM) images. First, pure frequency images are generated from low frequency to high frequency, and then, the magnification of each type of frequency image is implemented. By comparing the edge percentage of the SEM image to the self-generated frequency images, we can define the frequency ranges of the SEM images. Characterization of frequency ranges of SEM images benefits further processing and analysis of those SEM images, such as in noise filtering and contrast enhancement.

Full-field ultrasonic inspection for a composite sandwich plate skin-core debonding detection using laser-based ultrasonics

Science.gov (United States)

Chong, See Yenn; Victor, Jared J.; Todd, Michael D.

2017-04-01

In this paper, a full-field ultrasonic guided wave method is proposed to inspect a composite sandwich specimen made for an aircraft engine nacelle. The back skin/core interface of the specimen is built with two fabricated disbond defects (diameters of 12.7 mm and 25.4 mm) by removing areas of the adhesive used to bond the back skin to the core. A laser ultrasonic interrogation system (LUIS) incorporated with a disbond detection algorithm is developed. The system consists of a 1-kHz laser ultrasonic scanning system and a single fixed ultrasonic sensor to interrogate ultrasonic guided waves in the sandwich specimen. The interest area of 400 mm × 400 mm is scanned at a 0.5 mm scan interval. The corresponding full-field ultrasonic data is obtained and generated in the three-dimensional (3-D) space-time domain. Then, the 3-D full-field ultrasonic data is Fourier transformed and the ultrasonic frequency spectra are analyzed to determine the dominant frequency that is sensitive to the disbond defects. Continuous wavelet transform (CWT) based on fast Fourier transform (FFT) is implemented as a single-frequency bandpass filter to filter the full-field ultrasonic data in the 3-D space-time domain at the selected dominant frequency. The LUIS has shown the ability to detect the disbond with diameters of 11 mm and 23 mm which match to the pre-determined disbond sizes well. For future research, a robust signal processing algorithm and a model-based matched filter will be investigated to make the detection process autonomous and improve detectability

Direct and sustained intracellular delivery of exogenous molecules using acoustic-transfection with high frequency ultrasound

Science.gov (United States)

Yoon, Sangpil; Kim, Min Gon; Chiu, Chi Tat; Hwang, Jae Youn; Kim, Hyung Ham; Wang, Yingxiao; Shung, K. Kirk

2016-02-01

Controlling cell functions for research and therapeutic purposes may open new strategies for the treatment of many diseases. An efficient and safe introduction of membrane impermeable molecules into target cells will provide versatile means to modulate cell fate. We introduce a new transfection technique that utilizes high frequency ultrasound without any contrast agents such as microbubbles, bringing a single-cell level targeting and size-dependent intracellular delivery of macromolecules. The transfection apparatus consists of an ultrasonic transducer with the center frequency of over 150 MHz and an epi-fluorescence microscope, entitled acoustic-transfection system. Acoustic pulses, emitted from an ultrasonic transducer, perturb the lipid bilayer of the cell membrane of a targeted single-cell to induce intracellular delivery of exogenous molecules. Simultaneous live cell imaging using HeLa cells to investigate the intracellular concentration of Ca2+ and propidium iodide (PI) and the delivery of 3 kDa dextran labeled with Alexa 488 were demonstrated. Cytosolic delivery of 3 kDa dextran induced via acoustic-transfection was manifested by diffused fluorescence throughout whole cells. Short-term (6 hr) cell viability test and long-term (40 hr) cell tracking confirmed that the proposed approach has low cell cytotoxicity.

Under sodium ultrasonic viewing for Fast Breeder Reactors: a review

International Nuclear Information System (INIS)

Tarpara, Eaglekumar G.; Patankar, V.H.; Vijayan Varier, N.

2016-09-01

Liquid Metal Fast Breeder Reactors (LMFBR/FBR) are of two types: Loop type and Pool type. Many countries like USA, Japan, UK, Russia, China, France, Lithuania, Belgium, Korea, and India have worked extensively on these types of FBRs. FBRs are capable of breeding more fissionable fuel than it consumes like breeding of Plutonium-239 from non-fissionable Uranium-238. In FBR, heat is released by fission process and it must be captured and transferred to the electric generator by the liquid metal coolant (i.e. Sodium). Due to continuous operation and for safety and licensing reasons, periodic inspection and maintenance is required for reactor fuel assemblies which carry nuclear fuels. For this reason, under sodium ultrasonic imaging technique is adopted as in-service inspection activity for viewing of core of FBRs. Since liquid sodium is optically opaque, ultrasonic technique is the only method which can be employed for imaging in liquid sodium. In harsh conditions like high temperature and high radiation, there is a restriction on the development of possible ultrasonic visualization systems and selection of the transducer materials which can operate in the core region of reactor at around 200 °C during shutdown of reactor. This report provides a review of works related to ultrasonic imaging in sodium, different materials used in high temperature transducer assemblies and their different coupling/bonding techniques to achieve maximum transmission efficiency in high temperature sodium environment. The report also provides the overview of different architectures and imaging methods of transducer array elements which were used in LMFBRs for inspection and visualization of the reactor core sub-assemblies. The report is focused on a review of some possible beam forming techniques which may be used for nuclear applications for high temperature environment. Published information of the different simulation models are also reviewed which can be adopted to simulate the

Power MOSFET-diode-based limiter for high-frequency ultrasound systems.

Science.gov (United States)

Choi, Hojong; Kim, Min Gon; Cummins, Thomas M; Hwang, Jae Youn; Shung, K Kirk

2014-10-01

The purpose of the limiter circuits used in the ultrasound imaging systems is to pass low-voltage echo signals generated by ultrasonic transducers while preventing high-voltage short pulses transmitted by pulsers from damaging front-end circuits. Resistor-diode-based limiters (a 50 Ω resistor with a single cross-coupled diode pair) have been widely used in pulse-echo measurement and imaging system applications due to their low cost and simple architecture. However, resistor-diode-based limiters may not be suited for high-frequency ultrasound transducer applications since they produce large signal conduction losses at higher frequencies. Therefore, we propose a new limiter architecture utilizing power MOSFETs, which we call a power MOSFET-diode-based limiter. The performance of a power MOSFET-diode-based limiter was evaluated with respect to insertion loss (IL), total harmonic distortion (THD), and response time (RT). We compared these results with those of three other conventional limiter designs and showed that the power MOSFET-diode-based limiter offers the lowest IL (-1.33 dB) and fastest RT (0.10 µs) with the lowest suppressed output voltage (3.47 Vp-p) among all the limiters at 70 MHz. A pulse-echo test was performed to determine how the new limiter affected the sensitivity and bandwidth of the transducer. We found that the sensitivity and bandwidth of the transducer were 130% and 129% greater, respectively, when combined with the new power MOSFET-diode-based limiter versus the resistor-diode-based limiter. Therefore, these results demonstrate that the power MOSFET-diode-based limiter is capable of producing lower signal attenuation than the three conventional limiter designs at higher frequency operation. © The Author(s) 2014.

Inspection of copper canisters for spent nuclear fuel by means of ultrasound. Ultrasonic imaging, FSW monitoring with acoustic emission

International Nuclear Information System (INIS)

Stepinski, Tadeusz; Olofsson, Tomas; Wennerstroem, Erik

2006-12-01

This report contains the research results concerning advanced ultrasound for the inspection of copper canisters for spent nuclear fuel obtained at Signals and Systems, Uppsala University in years 2005/2006. In the first part of the report we propose a concept of monitoring of the friction stir welding (FSW) process by means of acoustic emission (AE) technique. First, we introduce the AE technique and then we present the principle of the system for monitoring the FSW process in cylindrical symmetry specific for the SKB canisters. We propose an omnidirectional circular array of ultrasonic transducers for receiving the AE signals generated by the FSW tool and the releases of the residual stress at canister's circumference. Finally, we review the theory of uniform circular arrays. The second part of the report is concerned with synthetic aperture focusing technique (SAFT) characterized by enhanced spatial resolution. We evaluate three different approaches to perform imaging with less computational cost than that of the extended SAFT (ESAFT) method proposed in our previous reports. First, a sparse version of ESAFT is presented, which solves the reconstruction problem only for a small set of the most probable scatterers in the image. A frequency domain the ω-k SAFT algorithm, which relies on the far-field approximation is presented in the second part. Finally, a detailed analysis of the most computationally intense step in the ESAFT and the sparse 2D deconvolution is presented. In the final part of the report we introduce basics of the 3D ultrasonic imaging that has a great potential in the inspection of the FSW welds. We discuss in some detail the three interrelated steps involved in the 3D ultrasonic imaging: data acquisition, 3D reconstruction, and 3D visualization

Inspection of copper canisters for spent nuclear fuel by means of ultrasound. Ultrasonic imaging, FSW monitoring with acoustic emission

Energy Technology Data Exchange (ETDEWEB)

Stepinski, Tadeusz (ed.); Olofsson, Tomas; Wennerstroem, Erik [Uppsala Univ., Dept. of Technical Sciences (Sweden). Signals and Systems

2006-12-15

This report contains the research results concerning advanced ultrasound for the inspection of copper canisters for spent nuclear fuel obtained at Signals and Systems, Uppsala University in years 2005/2006. In the first part of the report we propose a concept of monitoring of the friction stir welding (FSW) process by means of acoustic emission (AE) technique. First, we introduce the AE technique and then we present the principle of the system for monitoring the FSW process in cylindrical symmetry specific for the SKB canisters. We propose an omnidirectional circular array of ultrasonic transducers for receiving the AE signals generated by the FSW tool and the releases of the residual stress at canister's circumference. Finally, we review the theory of uniform circular arrays. The second part of the report is concerned with synthetic aperture focusing technique (SAFT) characterized by enhanced spatial resolution. We evaluate three different approaches to perform imaging with less computational cost than that of the extended SAFT (ESAFT) method proposed in our previous reports. First, a sparse version of ESAFT is presented, which solves the reconstruction problem only for a small set of the most probable scatterers in the image. A frequency domain the {omega}-k SAFT algorithm, which relies on the far-field approximation is presented in the second part. Finally, a detailed analysis of the most computationally intense step in the ESAFT and the sparse 2D deconvolution is presented. In the final part of the report we introduce basics of the 3D ultrasonic imaging that has a great potential in the inspection of the FSW welds. We discuss in some detail the three interrelated steps involved in the 3D ultrasonic imaging: data acquisition, 3D reconstruction, and 3D visualization.

A study on the nondestructive evaluation of carbon/carbon disk using ultrasonics

International Nuclear Information System (INIS)

Im, Kwang Hee; Yang, In Young; Jeong, Hyun Jo

1998-01-01

It is useful to perform nondestructive evaluation (NDE) to assess material properties and part homogeneity for carbon/carbon (C/C) composites because the manufacturing of C/C brake disks requires complicated and costly processes. In this work several ultrasonic techniques were applied to attributable to the manufacturing process. In a carbon/carbon brake disk manufactured by a combination of pitch impregnation and CVI(Vapor infiltration method), the spatial variation of ultrasonic velocity was measured and found to be consistent with the nonuniform densification behavior in the manufacturing process. Low frequency(5 MHz) through-transmission scans based on both amplitude and time-of-flight of the ultrasonic pulse were used for mapping out the material property inhomogeneity. These results were compared with those obtained by dry-coupling ultrasonics. A good correlation was found between ultrasonic velocity and material density on a set of small blocks cut out of the disk. Pulse-echo C-scans at higher frequency (25 MHz) were used to image near-sulfate material property anomalies associated with certain steps in the manufacturing process, such as the placement of spacers between disks during the final CVI.

Study of a new technique for measuring the travel time of ultrasonic waves using the frequency spectrum

International Nuclear Information System (INIS)

Santos, Allan Xavier dos

2010-01-01

During the operation of a nuclear plant and other industrial plants, the operational time and the exposition to severe working conditions may cause the wear of its components, consequently, compromising the safety and the performance of the installation. The implementation of periodical inspections helps to ensure the safe operation and the best performance of the plant. In this way, the use of ultrasonic techniques for inspection and materials characterization becomes more and more attractive, since they offer quick, precise results and are technically ease to implement. The usual ultrasonic techniques, need to the measure the travelling time of the ultrasonic wave in the material examined in order to extract information useful to characterize it. Thus, the measurement of the travelling time of the ultrasonic wave is the overriding factor in most of the applications made with ultrasound. In this work a new technique was developed for measuring the travelling time of the ultrasonic wave using a Fourier's Fast Transformer (FFT). It will be shown mathematically and experimentally that it is possible to use the ultrasonic signal in the frequency domain to determine the travelling time of the ultrasonic wave. Five experiments were carried out for the experimental validation of this new technique. The materials used were 20 ceramic pastilles with different porosities and 3 aluminum plates of different thicknesses. The obtained results have shown that the new technique proposed in this work was able to determine the travelling time of the ultrasonic wave with the same precision as the conventional technique. It was shown, furthermore, that this new technique is able to measure the travelling time of the ultrasonic wave in situations where the conventional technique cannot be applied greatly expanding the range of application of ultrasonic testing and inspections. (author)

Ultrasonic horn design for ultrasonic machining technologies

Directory of Open Access Journals (Sweden)

Naď M.

2010-07-01

Full Text Available Many of industrial applications and production technologies are based on the application of ultrasound. In many cases, the phenomenon of ultrasound is also applied in technological processes of the machining of materials. The main element of equipments that use the effects of ultrasound for machining technology is the ultrasonic horn – so called sonotrode. The performance of ultrasonic equipment, respectively ultrasonic machining technologies depends on properly designed of sonotrode shape. The dynamical properties of different geometrical shapes of ultrasonic horns are presented in this paper. Dependence of fundamental modal properties (natural frequencies, mode shapes of various sonotrode shapes for various geometrical parameters is analyzed. Modal analyses of the models are determined by the numerical simulation using finite element method (FEM design procedures. The mutual comparisons of the comparable parameters of the various sonotrode shapes are presented.

Ultrasonic and metallographic studies on AISI 4140 steel exposed to hydrogen at high pressure and temperature

Science.gov (United States)

Oruganti, Malavika

This thesis conducts an investigation to study the effects of hydrogen exposure at high temperature and pressure on the behavior of AISI 4140 steel. Piezoelectric ultrasonic technique was primarily used to evaluate surface longitudinal wave velocity and defect geometry variations, as related to time after exposure to hydrogen at high temperature and pressure. Critically refracted longitudinal wave technique was used for the former and pulse-echo technique for the latter. Optical microscopy and scanning electron microscopy were used to correlate the ultrasonic results with the microstructure of the steel and to provide better insight into the steel behavior. The results of the investigation indicate that frequency analysis of the defect echo, determined using the pulse-echo technique at regular intervals of time, appears to be a promising tool for monitoring defect growth induced by a high temperature and high pressure hydrogen-related attack.

Angle-of-arrival-based gesture recognition using ultrasonic multi-frequency signals

KAUST Repository

Chen, Hui

2017-11-02

Hand gestures are tools for conveying information, expressing emotion, interacting with electronic devices or even serving disabled people as a second language. A gesture can be recognized by capturing the movement of the hand, in real time, and classifying the collected data. Several commercial products such as Microsoft Kinect, Leap Motion Sensor, Synertial Gloves and HTC Vive have been released and new solutions have been proposed by researchers to handle this task. These systems are mainly based on optical measurements, inertial measurements, ultrasound signals and radio signals. This paper proposes an ultrasonic-based gesture recognition system using AOA (Angle of Arrival) information of ultrasonic signals emitted from a wearable ultrasound transducer. The 2-D angles of the moving hand are estimated using multi-frequency signals captured by a fixed receiver array. A simple redundant dictionary matching classifier is designed to recognize gestures representing the numbers from `0\\' to `9\\' and compared with a neural network classifier. Average classification accuracies of 95.5% and 94.4% are obtained, respectively, using the two classification methods.

Photoacoustic imaging of hidden dental caries by using a fiber-based probing system

Science.gov (United States)

Koyama, Takuya; Kakino, Satoko; Matsuura, Yuji

2017-04-01

Photoacoustic method to detect hidden dental caries is proposed. It was found that high frequency ultrasonic waves are generated from hidden carious part when radiating laser light to occlusal surface of model tooth. By making a map of intensity of these high frequency components, photoacoustic images of hidden caries were successfully obtained. A photoacoustic imaging system using a bundle of hollow optical fiber was fabricated for using clinical application, and clear photoacoustic image of hidden caries was also obtained by this system.

Analysis of the ultrasonic image of adrenal metastasis in primary lung cancer

International Nuclear Information System (INIS)

Bai Ling; Yang Tao; Tang Ying; Mao Jingning; Chen Wei; Wang Yong; Zhang Yan

2009-01-01

Objective: To investigate the ultrasonic image of adrenal metastasis in primary lung cancer. Methods: The ultrasonic imaging characteristics of fourteen patients with adrenal metastasis in primary lung cancer were retrospectively reviewed. In all the cases, US-guided percutaneous biopsy was performed for pathological evaluation during the clinical diagnosis. Results and Conclusion: In ultrasonography the adrenal metastatic tumors were manifested as solitary in all the cases, well-defined in 10 cases, irregularly shaped in 10 cases, hypoechoic in 13 cases, and 1 case showed cystoid structure in the tumor. The maximum diameter of the tumor was 3.0-15.3 cm. 9 cases were metastatic adenocarcinoma. The sonographic appearance of adrenal metastasis in primary lung cancer has its characteristics. Ultrasonography can find adrenal metastalic tumors easily and contribute to diagnosis. (authors)

An ultrasonic phased array applicator for deep localized hyperthermia

International Nuclear Information System (INIS)

Ocheltree, K.B.; Benkeser, P.J.; Foster, S.G.; Frizzell, L.A.; Cain, C.A.

1984-01-01

The use of an ultrasonic phased array applicator presents a major advantage over the fixed beam ultrasonic applicators which are typically used for clinical hyperthermia. Such an applicator allows focal region placement in the three dimensional treatment field by electronic steering instead of mechanical movement of the transducer assembly. The design of an array is discussed theoretically, considering that the constraints on grating lobes and power output for hyperthermic applications are quite different from those for imaging. The effects of various design parameters are discussed. Experimental results are presented for several arrays for frequencies under 1 Mhz

Evaluation of ultrasonic array imaging algorithms for inspection of a coarse grained material

Science.gov (United States)

Van Pamel, A.; Lowe, M. J. S.; Brett, C. R.

2014-02-01

Improving the ultrasound inspection capability for coarse grain metals remains of longstanding interest to industry and the NDE research community and is expected to become increasingly important for next generation power plants. A test sample of coarse grained Inconel 625 which is representative of future power plant components has been manufactured to test the detectability of different inspection techniques. Conventional ultrasonic A, B, and C-scans showed the sample to be extraordinarily difficult to inspect due to its scattering behaviour. However, in recent years, array probes and Full Matrix Capture (FMC) imaging algorithms, which extract the maximum amount of information possible, have unlocked exciting possibilities for improvements. This article proposes a robust methodology to evaluate the detection performance of imaging algorithms, applying this to three FMC imaging algorithms; Total Focusing Method (TFM), Phase Coherent Imaging (PCI), and Decomposition of the Time Reversal Operator with Multiple Scattering (DORT MSF). The methodology considers the statistics of detection, presenting the detection performance as Probability of Detection (POD) and probability of False Alarm (PFA). The data is captured in pulse-echo mode using 64 element array probes at centre frequencies of 1MHz and 5MHz. All three algorithms are shown to perform very similarly when comparing their flaw detection capabilities on this particular case.

Ensemble Empirical Mode Decomposition based methodology for ultrasonic testing of coarse grain austenitic stainless steels.

Science.gov (United States)

Sharma, Govind K; Kumar, Anish; Jayakumar, T; Purnachandra Rao, B; Mariyappa, N

2015-03-01

A signal processing methodology is proposed in this paper for effective reconstruction of ultrasonic signals in coarse grained high scattering austenitic stainless steel. The proposed methodology is comprised of the Ensemble Empirical Mode Decomposition (EEMD) processing of ultrasonic signals and application of signal minimisation algorithm on selected Intrinsic Mode Functions (IMFs) obtained by EEMD. The methodology is applied to ultrasonic signals obtained from austenitic stainless steel specimens of different grain size, with and without defects. The influence of probe frequency and data length of a signal on EEMD decomposition is also investigated. For a particular sampling rate and probe frequency, the same range of IMFs can be used to reconstruct the ultrasonic signal, irrespective of the grain size in the range of 30-210 μm investigated in this study. This methodology is successfully employed for detection of defects in a 50mm thick coarse grain austenitic stainless steel specimens. Signal to noise ratio improvement of better than 15 dB is observed for the ultrasonic signal obtained from a 25 mm deep flat bottom hole in 200 μm grain size specimen. For ultrasonic signals obtained from defects at different depths, a minimum of 7 dB extra enhancement in SNR is achieved as compared to the sum of selected IMF approach. The application of minimisation algorithm with EEMD processed signal in the proposed methodology proves to be effective for adaptive signal reconstruction with improved signal to noise ratio. This methodology was further employed for successful imaging of defects in a B-scan. Copyright © 2014. Published by Elsevier B.V.

Indoor Airborne Ultrasonic Wireless Communication Using OFDM Methods.

Science.gov (United States)

Jiang, Wentao; Wright, William M D

2017-09-01

Concerns still exist over the safety of prolonged exposure to radio frequency (RF) wireless transmissions and there are also potential data security issues due to remote signal interception techniques such as Bluesniping. Airborne ultrasound may be used as an alternative to RF for indoor wireless communication systems for securely transmitting data over short ranges, as signals are difficult to intercept from outside the room. Two types of air-coupled capacitive ultrasonic transducer were used in the implementation of an indoor airborne wireless communication system. One was a commercially available SensComp series 600 ultrasonic transducer with a nominal frequency of 50 kHz, and the other was a prototype transducer with a high- k dielectric layer operating at higher frequencies from 200 to 400 kHz. Binary phase-shift keying (BPSK), quadrature phase-shift keying (QPSK), and quadrature amplitude modulation (QAM)-based orthogonal frequency division multiplexing modulation methods were successfully implemented using multiple orthogonal subchannels. The modulated ultrasonic signal packets were synchronized using a wireless link, and a least-squares channel estimation algorithm was used to compensate the phase and amplitude distortion introduced by the air channel. By sending and receiving the ultrasonic signals using the SensComp transducers, the achieved maximum system data rate was up to 180 kb/s using 16-QAM with ultrasonic channels from 55 to 99 kHz, over a line-of-sight transmission distance of 6 m with no detectable errors. The transmission range could be extended to 9 and 11 m using QPSK and BPSK modulation schemes, respectively. The achieved data rates for the QPSK and BPSK schemes were 90 and 45 kb/s using the same bandwidth. For the high- k ultrasonic transducers, a maximum data rate up to 800 kb/s with no measurable errors was achieved up to a range of 0.7 m. The attainable transmission ranges were increased to 1.1 and 1.2 m with data rates of 400 and 200 kb

Ultrasonic inspection of composite hydrogen reservoirs using frequency diversity techniques

International Nuclear Information System (INIS)

Zellouf, D.; Goyette, J.; Massicotte, D.; Bose, T.K.

2000-01-01

During their service, cryogenic tanks are subjected to both hydrostatic and hygrothermic stresses. This can have as a consequence the initiation of the propagation of cracks within the structure of the material. Nevertheless, the analysis of ultrasonic signals collected during the inspection of composite materials must be dealt with carefully because of the presence of a strong background noise due to the reinforcement. This background noise results mostly from the interferences between the waves diffracted on the reinforcement. The target echo and the noise in which it is embedded both have the same frequency bandwidth. Thus we cannot use conventional linear filters to improve the signal-to-noise ratio

Point spread functions and deconvolution of ultrasonic images.

Science.gov (United States)

Dalitz, Christoph; Pohle-Fröhlich, Regina; Michalk, Thorsten

2015-03-01

This article investigates the restoration of ultrasonic pulse-echo C-scan images by means of deconvolution with a point spread function (PSF). The deconvolution concept from linear system theory (LST) is linked to the wave equation formulation of the imaging process, and an analytic formula for the PSF of planar transducers is derived. For this analytic expression, different numerical and analytic approximation schemes for evaluating the PSF are presented. By comparing simulated images with measured C-scan images, we demonstrate that the assumptions of LST in combination with our formula for the PSF are a good model for the pulse-echo imaging process. To reconstruct the object from a C-scan image, we compare different deconvolution schemes: the Wiener filter, the ForWaRD algorithm, and the Richardson-Lucy algorithm. The best results are obtained with the Richardson-Lucy algorithm with total variation regularization. For distances greater or equal twice the near field distance, our experiments show that the numerically computed PSF can be replaced with a simple closed analytic term based on a far field approximation.

Frequency domain analysis of knock images

Science.gov (United States)

Qi, Yunliang; He, Xin; Wang, Zhi; Wang, Jianxin

2014-12-01

High speed imaging-based knock analysis has mainly focused on time domain information, e.g. the spark triggered flame speed, the time when end gas auto-ignition occurs and the end gas flame speed after auto-ignition. This study presents a frequency domain analysis on the knock images recorded using a high speed camera with direct photography in a rapid compression machine (RCM). To clearly visualize the pressure wave oscillation in the combustion chamber, the images were high-pass-filtered to extract the luminosity oscillation. The luminosity spectrum was then obtained by applying fast Fourier transform (FFT) to three basic colour components (red, green and blue) of the high-pass-filtered images. Compared to the pressure spectrum, the luminosity spectra better identify the resonant modes of pressure wave oscillation. More importantly, the resonant mode shapes can be clearly visualized by reconstructing the images based on the amplitudes of luminosity spectra at the corresponding resonant frequencies, which agree well with the analytical solutions for mode shapes of gas vibration in a cylindrical cavity.

Industrial Applications of High Power Ultrasonics

Science.gov (United States)

Patist, Alex; Bates, Darren

Since the change of the millennium, high-power ultrasound has become an alternative food processing technology applicable to large-scale commercial applications such as emulsification, homogenization, extraction, crystallization, dewatering, low-temperature pasteurization, degassing, defoaming, activation and inactivation of enzymes, particle size reduction, extrusion, and viscosity alteration. This new focus can be attributed to significant improvements in equipment design and efficiency during the late 1990 s. Like most innovative food processing technologies, high-power ultrasonics is not an off-the-shelf technology, and thus requires careful development and scale-up for each and every application. The objective of this chapter is to present examples of ultrasonic applications that have been successful at the commercialization stage, advantages, and limitations, as well as key learnings from scaling up an innovative food technology in general.

X-ray elastography: Modification of x-ray phase contrast images using ultrasonic radiation pressure

International Nuclear Information System (INIS)

Hamilton, Theron J.; Bailat, Claude; Rose-Petruck, Christoph; Diebold, Gerald J.; Gehring, Stephan; Laperle, Christopher M.; Wands, Jack

2009-01-01

The high resolution characteristic of in-line x-ray phase contrast imaging can be used in conjunction with directed ultrasound to detect small displacements in soft tissue generated by differential acoustic radiation pressure. The imaging method is based on subtraction of two x-ray images, the first image taken with, and the second taken without the presence of ultrasound. The subtraction enhances phase contrast features and, to a large extent, removes absorption contrast so that differential movement of tissues with different acoustic impedances or relative ultrasonic absorption is highlighted in the image. Interfacial features of objects with differing densities are delineated in the image as a result of both the displacement introduced by the ultrasound and the inherent sensitivity of x-ray phase contrast imaging to density variations. Experiments with ex vivo murine tumors and human tumor phantoms point out a diagnostic capability of the method for identifying tumors.

Ultrasonic testing of materials at level 2

International Nuclear Information System (INIS)

1988-06-01

Ultrasonic inspection is a nondestructive method in which high frequency sound waves are introduced into the material being inspected. Ultrasonic testing has a superior penetrating power to radiography and can detect flaws deep in the test specimen (say up to about 6 to 7 meters of steel). It is quite sensitive to small flaws and allows the precise determination of the location and size of the flaws. Basic ultrasonic test methods such as the through transmission method and the resonance method, sensors and testing techniques are described. Pulse echo type flaw detectors and their applications for inspection of welds are surveyed. Ultrasonic standards, calibration of the equipment and evaluation methods are presented. Examples of practical applications in welding, casting and forging processes are given. Figs and tabs

Image based EFIT simulation for nondestructive ultrasonic testing of austenitic steel

International Nuclear Information System (INIS)

Nakahata, Kazuyuki; Hirose, Sohichi; Schubert, Frank; Koehler, Bernd

2009-01-01

The ultrasonic testing (UT) of an austenitic steel with welds is difficult due to the acoustic anisotropy and local heterogeneity. The ultrasonic wave in the austenitic steel is skewed along crystallographic directions and scattered by weld boundaries. For reliable UT, a straightforward simulation tool to predict the wave propagation is desired. Here a combined method of elastodynamic finite integration technique (EFIT) and digital image processing is developed as a wave simulation tool for UT. The EFIT is a grid-based explicit numerical method and easily treats different boundary conditions which are essential to model wave propagation in heterogeneous materials. In this study, the EFIT formulation in anisotropic and heterogeneous materials is briefly described and an example of a two dimensional simulation of a phased array UT in an austenitic steel bar is demonstrated. In our simulation, a picture of the surface of the steel bar with a V-groove weld is scanned and fed into the image based EFIT modeling. (author)

High-temperature ultrasonic measurements applied to directly heated samples

International Nuclear Information System (INIS)

Moore, R.I.; Taylor, R.E.

1984-01-01

High-temperature ultrasonic measurements of Young's modulus were made of graphite samples heated directly. The samples were cylindrical rods of the same geometry as that used in the multiproperty apparatus for simultaneous/consecutive measurements of a number of thermophysical properties to high temperatures. The samples were resonated in simple longitudinal vibration modes. Measurements were performed up to 2000 K. Incorporation of ultrasonic measurements of Young's modulus in the capabilities of the multiproperty apparatus is valuable because (i) ultrasonic measurements can be related to normal destructive measurements of this property; (ii) they can be used for screening materials or acceptance testing of specimens; (iii) they can be used to increase the understanding of thermophysical properties and property correlations. (author)

Enhancement of submarine pressure hull steel ultrasonic inspection using imaging and artificial intelligence

Science.gov (United States)

Hay, D. Robert; Brassard, Michel; Matthews, James R.; Garneau, Stephane; Morchat, Richard

1995-06-01

The convergence of a number of contemporary technologies with increasing demands for improvements in inspection capabilities in maritime applications has created new opportunities for ultrasonic inspection. An automated ultrasonic inspection and data collection system APHIUS (automated pressure hull intelligent ultrasonic system), incorporates hardware and software developments to meet specific requirements for the maritime vessels, in particular, submarines in the Canadian Navy. Housed within a hardened portable computer chassis, instrumentation for digital ultrasonic data acquisition and transducer position measurement provide new capabilities that meet more demanding requirements for inspection of the aging submarine fleet. Digital data acquisition enables a number of new important capabilites including archiving of the complete inspection session, interpretation assistance through imaging, and automated interpretation using artificial intelligence methods. With this new reliable inspection system, in conjunction with a complementary study of the significance of real defect type and location, comprehensive new criteria can be generated which will eliminate unnecessary defect removal. As a consequence, cost savings will be realized through shortened submarine refit schedules.

Synchronous ultrasonic Doppler imaging of magnetic microparticles in biological tissues

Energy Technology Data Exchange (ETDEWEB)

Pyshnyi, Michael Ph. [Institute of Biochemical Physics, Russian Academy of Sciences, Kosygin St. 4, Moscow 119991 (Russian Federation); Kuznetsov, Oleg A. [Institute of Biochemical Physics, Russian Academy of Sciences, Kosygin St. 4, Moscow 119991 (Russian Federation)], E-mail: kuznetsov_oa@yahoo.com; Pyshnaya, Svetlana V.; Nechitailo, Galina S.; Kuznetsov, Anatoly A. [Institute of Biochemical Physics, Russian Academy of Sciences, Kosygin St. 4, Moscow 119991 (Russian Federation)

2009-05-15

We considered applicability of acoustic imaging technology for the detection of magnetic microparticles and nanoparticles inside soft biological tissues. Such particles are widely used for magnetically targeted drug delivery and magnetic hyperthermia. We developed a new method of ultrasonic synchronous tissue Doppler imaging with magnetic modulation for in vitro and in vivo detection and visualization of magnetic ultradisperse objects in soft tissues. Prototype hardware with appropriate software was produced and the method was successfully tested on magnetic microparticles injected into an excised pig liver.

Synchronous ultrasonic Doppler imaging of magnetic microparticles in biological tissues

International Nuclear Information System (INIS)

Pyshnyi, Michael Ph.; Kuznetsov, Oleg A.; Pyshnaya, Svetlana V.; Nechitailo, Galina S.; Kuznetsov, Anatoly A.

2009-01-01

We considered applicability of acoustic imaging technology for the detection of magnetic microparticles and nanoparticles inside soft biological tissues. Such particles are widely used for magnetically targeted drug delivery and magnetic hyperthermia. We developed a new method of ultrasonic synchronous tissue Doppler imaging with magnetic modulation for in vitro and in vivo detection and visualization of magnetic ultradisperse objects in soft tissues. Prototype hardware with appropriate software was produced and the method was successfully tested on magnetic microparticles injected into an excised pig liver.

High-frequency 3D echodentographic imaging modality for early assessment of periodontal diseases: in vitro study

Science.gov (United States)

Mahmoud, Ahmed M.; Ngan, Peter; Crout, Richard; Mukdadi, Osama M.

2009-02-01

The use of ultrasound in dentistry is still an open growing area of research. Currently, there is a lack of imaging modalities to accurately predict minute structures and defects in the jawbone. In particular, the inability of 2D radiographic images to detect bony periodontal defects resulted from infection of the periodontium. This study investigates the feasibility of high frequency ultrasound to reconstruct high resolution 3D surface images of human jawbone. Methods: A dentate and non-dentate mandibles were used in this study. The system employs high frequency single-element ultrasound focused transducers (15-30 MHz) for scanning. Continuous acquisition using a 1 GHz data acquisition card is synchronized with a high precision two-dimensional stage positioning system of +/-1 μm resolution for acquiring accurate and quantitative measurements of the mandible in vitro. Radio frequency (RF) signals are acquired laterally 44-45.5 μm apart for each frame. Different frames are reconstructed 500 μm apart for the 3D reconstruction. Signal processing algorithms are applied on the received ultrasound signals for filtering, focusing, and envelope detection before frame reconstruction. Furthermore, an edge detection technique is adopted to detect the bone surface in each frame. Finally, all edges are combined together in order to render a 3D surface image of the jawbone. Major anatomical landmarks on the resultant images were confirmed with the anatomical structures on the mandibles to show the efficacy of the system. Comparison were also made with conventional 2D radiographs to show the superiority of the ultrasound imaging system in diagnosing small defects in the lateral, axial and elevation planes of space. Results: The landmarks on all ultrasound images matched with those on the mandible, indicating the efficacy of the system in detecting small structures in human jaw bones. Comparison with conventional 2D radiographic images of the same mandible showed superiority of

Backward ray tracing for ultrasonic imaging

NARCIS (Netherlands)

Breeuwer, R.

1990-01-01

Focused ultrasonic beams frequently pass one or more media interfaces, strongly affecting the ultrasonic beamshape and focusing. A computer program, based on backward ray tracing was developed to compute the shape of a corrected focusing mirror. This shape is verified with another program; then the

Void detection beneath reinforced concrete sections: The practical application of ground-penetrating radar and ultrasonic techniques

Science.gov (United States)

Cassidy, Nigel J.; Eddies, Rod; Dods, Sam

2011-08-01

Ground-penetrating radar (GPR) and ultrasonic 'pulse echo' techniques are well-established methods for the imaging, investigation and analysis of steel reinforced concrete structures and are important civil engineering survey tools. GPR is, arguably, the more widely-used technique as it is suitable for a greater range of problem scenarios (i.e., from rebar mapping to moisture content determination). Ultrasonic techniques are traditionally associated with the engineering-based, non-destructive testing of concrete structures and their integrity analyses (e.g., flaw detection, shear/longitudinal velocity determination, etc). However, when used in an appropriate manner, both techniques can be considered complementary and provide a unique way of imaging the sub-surface that is suited to a range of geotechnical problems. In this paper, we present a comparative study between mid-to-high frequency GPR (450 MHz and 900 MHz) and array-based, shear wave, pulse-echo ultrasonic surveys using proprietary instruments and conventional GPR data processing and visualisation techniques. Our focus is the practical detection of sub-metre scale voids located under steel reinforced concrete sections in realistic survey conditions (e.g., a capped, relict mine shaft or vent). Representative two-dimensional (2D) sections are presented for both methods illustrating the similarities/differences in signal response and the temporal-spatial target resolutions achieved with each technique. The use of three-dimensional data volumes and time slices (or 'C-scans') for advanced interpretation is also demonstrated, which although common in GPR applications is under-utilised as a technique in general ultrasonic surveys. The results show that ultrasonic methods can perform as well as GPR for this specific investigation scenario and that they have the potential of overcoming some of the inherent limitations of GPR investigations (i.e., the need for careful antenna frequency selection and survey design in

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

OpenAIRE

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

2016-01-01

A 1.5 MHz prolate spheroidal therapeutic array with 128 circular elements was designed to accommodate standard imaging arrays for ultrasonic image-guided hyperthermia. The implementation of this dual-array system integrates real-time therapeutic and imaging functions with a single ultrasound system (Vantage 256, Verasonics). To facilitate applications involving small animal imaging and therapy the array was designed to have a beam depth of field smaller than 3.5 mm and to electronically steer...

Ultrasonic imaging algorithms with limited transmission cycles for rapid nondestructive evaluation.

Science.gov (United States)

Moreau, Ludovic; Drinkwater, Bruce W; Wilcox, Paul D

2009-09-01

Imaging algorithms recently developed in ultrasonic nondestructive testing (NDT) have shown good potential for defect characterization. Many of them are based on the concept of collecting the full matrix of data, obtained by firing each element of an ultrasonic phased array independently, while collecting the data with all elements. Because of the finite sound velocity in the test structure, 2 consecutive firings must be separated by a minimum time interval. Depending on the number of elements in a given array, this may become problematic if data must be collected within a short time, as it is often the case, for example, in an industrial context. An obvious way to decrease the duration of data capture is to use a sparse transmit aperture, in which only a restricted number of elements are used to transmit ultrasonic waves. This paper compares 2 approaches aimed at producing an image on the basis of restricted data: the common source method and the effective aperture technique. The effective aperture technique is based on the far-field approximation, and no similar approach exists for the near-field. This paper investigates the performance of this technique in near-field conditions, where most NDT applications are made. First, these methods are described and their point spread functions are compared with that of the Total Focusing Method (TFM), which consists of focusing the array at every point in the image. Then, a map of efficiency is given for the different algorithms in the near-field. The map can be used to select the most appropriate algorithm. Finally, this map is validated by testing the different algorithms on experimental data.

Design and development of an ultrasonic pulser-receiver unit for non-destructive testing of materials

International Nuclear Information System (INIS)

Patankar, V.H.; Joshi, V.M.

2002-11-01

The pulser/receiver constitutes the most vital part of an ultrasonic flaw detector or an ultrasonic imaging system used for inspection of materials. The ultrasonic properties of the material and resolution requirements govern the choice of the frequency of ultrasound that can be optimally used. The pulser/receiver in turn decides the efficiency of excitation of the transducer and the overall signal to noise ratio of the system for best sensitivity and resolution. A variety of pulsers are used in the ultrasonic instruments employed for materials inspection. This report describes a square wave type of an ultrasonic pulser-receiver unit developed at Ultrasonic Instrumentation Section, Electronics Division, BARC. It has been primarily designed for excitation of the transducer that is used with a multi-channel ultrasonic imaging system ULTIMA 100M targeted for inspection of SS403 billets, which are in turn used as the base material for fabrication of end fittings for coolant channels of pressurized heavy water nuclear reactors (PHWRs). The design of the pulser is based upon very fast MOSFETs, configured as electronic switches. The pulser is operated with a linear bipolar H.V. supply (+/- 500V max.). The receiver provides a 60 dB gain with a -3 dB BW of 40 MHz. This pulser/receiver unit has been successfully interfaced with a 4 channel ULTIMA 100 M4 multichannel ultrasonic C-scan imaging system, also designed and developed by the authors at Ultrasonic Instrumentation Section (Electronics Division, BARC) and supplied to Centre for Design and Manufacturer - CDM, BARC. This system is being regularly used in C-scan imaging mode for volumetric inspection of SS403 billets for end fittings of 500 MWe PHWRs. (author)

Nanoparticles as image enhancing agents for ultrasonography

Energy Technology Data Exchange (ETDEWEB)

Liu Jun [Biomedical Engineering Department, Ohio State University, 270 Bevis Hall, 1080 Carmack Rd, Columbus, OH 43210 (United States); Levine, Andrea L [Department of Veterinary Biosciences, Ohio State University, 1925 Coffey Rd, Columbus, OH 43210 (United States); Mattoon, John S [Department of Veterinary Clinical Sciences, Ohio State University, 1151 Veterinary Hospital, 601 Vernon Tharp St., Columbus, OH 43210 (United States); Yamaguchi, Mamoru [Department of Veterinary Biosciences, Ohio State University, 1925 Coffey Rd, Columbus, OH 43210 (United States); Lee, Robert J [Division of Pharmaceutics, College of Pharmacy, NCI Comprehensive Cancer Center, and NSF Nanoscale Science and Engineering Center, Ohio State University, 500 West 12th Avenue, Columbus, OH 43210 (United States); Pan Xueliang [Department of Statistics, Ohio State University, 1958 Neil Avenue, Columbus, OH 43210 (United States); Rosol, Thomas J [Department of Veterinary Biosciences, Ohio State University, 1925 Coffey Rd, Columbus, OH 43210 (United States)

2006-05-07

Nanoparticles have drawn great attention as targeted imaging and/or therapeutic agents. The small size of the nanoparticles allows them to target cells that are beyond capillary vasculature, such as cancer cells. We investigated the effect of solid nanoparticles for enhancing ultrasonic grey scale images in tissue phantoms and mouse livers in vivo. Silica nanospheres (100 nm) were dispersed in agarose at 1-2.5% mass concentration and imaged by a high-resolution ultrasound imaging system (transducer centre frequency: 30 MHz). Polystyrene particles of different sizes (500-3000 nm) and concentrations (0.13-0.75% mass) were similarly dispersed in agarose and imaged. Mice were injected intravenously with nanoparticle suspensions in saline. B-mode images of the livers were acquired at different time points after particle injection. An automated computer program was used to quantify the grey scale changes. Ultrasonic reflections were observed from nanoparticle suspensions in agarose gels. The image brightness, i.e., mean grey scale level, increased with particle size and concentration. The mean grey scale of mouse livers also increased following particle administration. These results indicated that it is feasible to use solid nanoparticles as contrast enhancing agents for ultrasonic imagin000.

Analytical reverse time migration: An innovation in imaging of infrastructures using ultrasonic shear waves.

Science.gov (United States)

Asadollahi, Aziz; Khazanovich, Lev

2018-04-11

The emergence of ultrasonic dry point contact (DPC) transducers that emit horizontal shear waves has enabled efficient collection of high-quality data in the context of a nondestructive evaluation of concrete structures. This offers an opportunity to improve the quality of evaluation by adapting advanced imaging techniques. Reverse time migration (RTM) is a simulation-based reconstruction technique that offers advantages over conventional methods, such as the synthetic aperture focusing technique. RTM is capable of imaging boundaries and interfaces with steep slopes and the bottom boundaries of inclusions and defects. However, this imaging technique requires a massive amount of memory and its computation cost is high. In this study, both bottlenecks of the RTM are resolved when shear transducers are used for data acquisition. An analytical approach was developed to obtain the source and receiver wavefields needed for imaging using reverse time migration. It is shown that the proposed analytical approach not only eliminates the high memory demand, but also drastically reduces the computation time from days to minutes. Copyright © 2018 Elsevier B.V. All rights reserved.

Estimation of Scatterer Diameter by Normalized Power Spectrum of High-Frequency Ultrasonic RF Echo for Assessment of Red Blood Cell Aggregation

Science.gov (United States)

Fukushima, Taku; Hasegawa, Hideyuki; Kanai, Hiroshi

2011-07-01

Red blood cell (RBC) aggregation, as one of the determinants of blood viscosity, plays an important role in blood rheology, including the condition of blood. RBC aggregation is induced by the adhesion of RBCs when the electrostatic repulsion between RBCs weakens owing to increases in protein and saturated fatty acid levels in blood, excessive RBC aggregation leads to various circulatory diseases. This study was conducted to establish a noninvasive quantitative method for assessment of RBC aggregation. The power spectrum of ultrasonic RF echoes from nonaggregating RBCs, which shows the frequency property of scattering, exhibits Rayleigh behavior. On the other hand, ultrasonic RF echoes from aggregating RBCs contain the components of reflection, which have no frequency dependence. By dividing the measured power spectrum of echoes from RBCs in the lumen by that of echoes from a posterior wall of the vein in the dorsum manus, the attenuation property of the propagating medium and the frequency responses of transmitting and receiving transducers are removed from the former spectrum. RBC aggregation was assessed by the diameter of a scatterer, which was estimated by minimizing the square difference between the measured normalized power spectrum and the theoretical power spectrum. In this study, spherical scatterers with diameters of 5, 11, 15, and 30 µm were measured in basic experiments. The estimated scatterer diameters were close to the actual diameters. Furthermore, the transient change of the scatterer diameters were measured in an in vivo experiment with respect to a 24-year-old healthy male during the avascularization using a cuff. The estimated diameters (12-22 µm) of RBCs during avascularization were larger than the diameters (4-8 µm) at rest and after recirculation. These results show the possibility of the use of the proposed method for noninvasive assessment of RBC aggregation.

Image enhancement by spatial frequency post-processing of images obtained with pupil filters

Science.gov (United States)

Estévez, Irene; Escalera, Juan C.; Stefano, Quimey Pears; Iemmi, Claudio; Ledesma, Silvia; Yzuel, María J.; Campos, Juan

2016-12-01

The use of apodizing or superresolving filters improves the performance of an optical system in different frequency bands. This improvement can be seen as an increase in the OTF value compared to the OTF for the clear aperture. In this paper we propose a method to enhance the contrast of an image in both its low and its high frequencies. The method is based on the generation of a synthetic Optical Transfer Function, by multiplexing the OTFs given by the use of different non-uniform transmission filters on the pupil. We propose to capture three images, one obtained with a clear pupil, one obtained with an apodizing filter that enhances the low frequencies and another one taken with a superresolving filter that improves the high frequencies. In the Fourier domain the three spectra are combined by using smoothed passband filters, and then the inverse transform is performed. We show that we can create an enhanced image better than the image obtained with the clear aperture. To evaluate the performance of the method, bar tests (sinusoidal tests) with different frequency content are used. The results show that a contrast improvement in the high and low frequencies is obtained.

Detection of fastener loosening in simple lap joint based on ultrasonic wavefield imaging

Science.gov (United States)

Gooda Sahib, M. I.; Leong, S. J.; Chia, C. C.; Mustapha, F.

2017-12-01

Joints in aero-mechanical structures are critical elements that ensure the structural integrity but they are prone to damages. Inspection of such joints that have no prior baseline data is really challenging but it can be possibly done using the Ultrasonic Propagation Imager (UPI). The feasibility of applying UPI for detection of loosened fastener is investigated in this study. A simple lap joint specimen made by connecting two pieces of 2.5mm thick SAE304 stainless steel plates using five M6 screws and nuts has been used in this study. All fasteners are tightened to 10Nm but one of them is completely loosened to simulate the damage. The wavefield data is processed into ultrasonic wavefield propagation video and a series of spectral amplitude images. The spectral images showed noticeable amplitude difference at the loosened fastener, hence confirmed the feasibility of using UPI for structural joints inspection. A simple contrast maximization method is also introduced to improve the result.

Bipolar-power-transistor-based limiter for high frequency ultrasound imaging systems.

Science.gov (United States)

Choi, Hojong; Yang, Hao-Chung; Shung, K Kirk

2014-03-01

High performance limiters are described in this paper for applications in high frequency ultrasound imaging systems. Limiters protect the ultrasound receiver from the high voltage (HV) spikes produced by the transmitter. We present a new bipolar power transistor (BPT) configuration and compare its design and performance to a diode limiter used in traditional ultrasound research and one commercially available limiter. Limiter performance depends greatly on the insertion loss (IL), total harmonic distortion (THD) and response time (RT), each of which will be evaluated in all the limiters. The results indicated that, compared with commercial limiter, BPT-based limiter had less IL (-7.7 dB), THD (-74.6 dB) and lower RT (43 ns) at 100 MHz. To evaluate the capability of these limiters, they were connected to a 100 MHz single element transducer and a two-way pulse-echo test was performed. It was found that the -6 dB bandwidth and sensitivity of the transducer using BPT-based limiter were better than those of the commercial limiter by 22% and 140%, respectively. Compared to the commercial limiter, BPT-based limiter is shown to be capable of minimizing signal attenuation, RT and THD at high frequencies and is thus suited for high frequency ultrasound applications. Copyright © 2013 Elsevier B.V. All rights reserved.

High-power ultrasonic processing: Recent developments and prospective advances

Science.gov (United States)

Gallego-Juarez, Juan A.

2010-01-01

Although the application of ultrasonic energy to produce or to enhance a wide variety of processes have been explored since about the middle of the 20th century, only a reduced number of ultrasonic processes have been established at industrial level. However, during the last ten years the interest in ultrasonic processing has revived particularly in industrial sectors where the ultrasonic technology may represent a clean and efficient tool to improve classical existing processes or an innovation alternative for the development of new processes. Such seems to be the case of relevant sectors such as food industry, environment, pharmaceuticals and chemicals manufacture, machinery, mining, etc where power ultrasound is becoming an emerging technology for process development. The possible major problem in the application of high-intensity ultrasound on industrial processing is the design and development of efficient power ultrasonic systems (generators and reactors) capable of large scale successful operation specifically adapted to each individual process. In the area of ultrasonic processing in fluid media and more specifically in gases, the development of the steppedplate transducers and other power ge with extensive radiating surface has strongly contributed to the implementation at semi-industrial and industrial stage of several commercial applications, in sectors such as food and beverage industry (defoaming, drying, extraction, etc), environment (air cleaning, sludge filtration, etc...), machinery and process for manufacturing (textile washing, paint manufacture, etc). The development of different cavitational reactors for liquid treatment in continuous flow is helping to introduce into industry the wide potential of the area of sonochemistry. Processes such as water and effluent treatment, crystallization, soil remediation, etc have been already implemented at semi-industrial and/or industrial stage. Other single advances in sectors like mining or energy have

Monitoring Low-Cycle Fatigue Material-Degradation by Ultrasonic Methods

Directory of Open Access Journals (Sweden)

R. Himawan

2010-08-01

Full Text Available Any system consisting of structural material often undergoes fatigue, which is caused by dynamic load cycle. As a structural system, nuclear power plant is very likely to have low-cycle fatigue at many of its components. Taking into account the importance of monitoring low-cycle fatigue on structural components to prevent them from getting failure, the authors have conducted a work to monitor material degradation caused by low-cycle fatigue by using ultrasonic method. An alloy of Cu-40Zn was used as a test specimen. Ultrasonic water immersion procedure was employed in this ultrasonic test. The probe used is a focusing type and has frequency as high as 15 MHz. The specimen area tested is in the middle part divided into 14 points × 23 points. The results, which were frequency spectrums, were analyzed using two parameters: frequency spectrum peak intensity and attenuation function gradient. The analysis indicates that peak intensity increases at the beginning of load cycle and then decreases. Meanwhile, gradient of attenuation function is lower at the beginning of fatigue process, and then consistently gets higher. It concludes that low-fatigue material degradation can be monitored by using ultrasonic method.

Schlieren imaging of the standing wave field in an ultrasonic acoustic levitator

Science.gov (United States)

Rendon, Pablo Luis; Boullosa, Ricardo R.; Echeverria, Carlos; Porta, David

2015-11-01

We consider a model of a single axis acoustic levitator consisting of two cylinders immersed in air and directed along the same axis. The first cylinder has a flat termination and functions as a sound emitter, and the second cylinder, which is simply a refector, has the side facing the first cylinder cut out by a spherical surface. By making the first cylinder vibrate at ultrasonic frequencies a standing wave is produced in the air between the cylinders which makes it possible, by means of the acoustic radiation pressure, to levitate one or several small objects of different shapes, such as spheres or disks. We use schlieren imaging to observe the acoustic field resulting from the levitation of one or several objects, and compare these results to previous numerical approximations of the field obtained using a finite element method. The authors acknowledge financial support from DGAPA-UNAM through project PAPIIT IN109214.

Beginning of fish defrosting by using non-destructive ultrasonic technique

International Nuclear Information System (INIS)

Malainine, M; Faiz, B; Izbaim, D; Aboudaoud, I; Moudden, A; Maze, G

2012-01-01

During the experiments carried out on the monitoring and the study of fish defrosting by an ultrasonic technique, we have difficulties in detecting the beginning of the thawing which is an important criterion of fish quality control. To address this problem, we use the Singular Value Decomposition method (SVD) which is a mathematical tool that permits to separate the high and low energies of an histogram. The image representing low energy signals indicates the start of the thawing by showing an echo that was hidden in the original image for cod fish. Using transducers for central frequencies above 500 kHz the observed results are not very good. Therefore, this method is suitable for fish which fat content is medium or low.

Bulk ultrasonic NDE of metallic components at high temperature using magnetostrictive transducers

Science.gov (United States)

Ashish, Antony Jacob; Rajagopal, Prabhu; Balasubramaniam, Krishnan; Kumar, Anish; Rao, B. Purnachandra; Jayakumar, Tammana

2017-02-01

Online ultrasonic NDE at high-temperature is of much interest to the power, process and automotive industries in view of possible savings in downtime. This paper describes a novel approach to developing ultrasonic transducers capable of high-temperature in-situ operation using the principle of magnetostriction. Preliminary design from previous research by the authors [1] is extended for operation at 1 MHz, and at elevated temperatures by amorphous metallic strips as the magnetostrictive core. Ultrasonic signals in pulse-echo mode are experimentally obtained from the ultrasonic transducer thus developed, in a simulated high-temperature environment of 350 °C for 10 hours. Advantages and challenges for practical deployment of this approach are discussed.

High Frame Rate Synthetic Aperture 3D Vector Flow Imaging

DEFF Research Database (Denmark)

Villagómez Hoyos, Carlos Armando; Holbek, Simon; Stuart, Matthias Bo

2016-01-01

, current volumetric ultrasonic flow methods are limited to one velocity component or restricted to a reduced field of view (FOV), e.g. fixed imaging planes, in exchange for higher temporal resolutions. To solve these problems, a previously proposed accurate 2-D high frame rate vector flow imaging (VFI...

Quality control of disinfection in ultrasonic baths

Energy Technology Data Exchange (ETDEWEB)

Schoene, H. [Technical University Dresden (Germany). Faculty of Mechanical Engineering; Jatzwauk, L. [University Hospital of the Technical University Dresden (Germany). Abt. Krankenhaushygiene

2002-07-01

Numerous investigations under laboratory conditions confirmed the microbicidal efficacy of ultrasonication. Morphological destruction was shown on bacteria and fungi as well as on different virus species. Ultrasonic treatment seems to increase the effect of different antibiotics and disinfectants. Reasons for this synergism are largely unknown and uninvestigated, but the active principle seems to bee the dispersing effect of ultrasonication in combination with the destruction of cell wall or cell membrane. Unfortunately no validation of test conditions exists for most of these investigations, regarding intensity and frequency of ultrasonic waves, temperature of liquid medium and measurement of cavitation which is an essential part of physical and chemical effects in ultrasonic baths. In contrast to most laboratory experiments sound density of ultrasound for treatment of medical instruments is below 1 W/cm{sup 2} because instruments will be destroyed under stronger ultrasonic conditions. The frequency is below 50 KHz. This paper describes bactericidal and fungicidal effects of low- intensity-ultrasonication and its synergistical support to chemical disinfection. (orig.)

Front-end receiver electronics for high-frequency monolithic CMUT-on-CMOS imaging arrays.

Science.gov (United States)

Gurun, Gokce; Hasler, Paul; Degertekin, F

2011-08-01

This paper describes the design of CMOS receiver electronics for monolithic integration with capacitive micromachined ultrasonic transducer (CMUT) arrays for highfrequency intravascular ultrasound imaging. A custom 8-inch (20-cm) wafer is fabricated in a 0.35-μm two-poly, four-metal CMOS process and then CMUT arrays are built on top of the application specific integrated circuits (ASICs) on the wafer. We discuss advantages of the single-chip CMUT-on-CMOS approach in terms of receive sensitivity and SNR. Low-noise and high-gain design of a transimpedance amplifier (TIA) optimized for a forward-looking volumetric-imaging CMUT array element is discussed as a challenging design example. Amplifier gain, bandwidth, dynamic range, and power consumption trade-offs are discussed in detail. With minimized parasitics provided by the CMUT-on-CMOS approach, the optimized TIA design achieves a 90 fA/√Hz input-referred current noise, which is less than the thermal-mechanical noise of the CMUT element. We show successful system operation with a pulseecho measurement. Transducer-noise-dominated detection in immersion is also demonstrated through output noise spectrum measurement of the integrated system at different CMUT bias voltages. A noise figure of 1.8 dB is obtained in the designed CMUT bandwidth of 10 to 20 MHz.

Embedded fiber optic ultrasonic sensors and generators

Science.gov (United States)

Dorighi, John F.; Krishnaswamy, Sridhar; Achenbach, Jan D.

1995-04-01

Ultrasonic sensors and generators based on fiber-optic systems are described. It is shown that intrinsic fiber optic Fabry-Perot ultrasound sensors that are embedded in a structure can be stabilized by actively tuning the laser frequency. The need for this method of stabilization is demonstrated by detecting piezoelectric transducer-generated ultrasonic pulses in the presence of low frequency dynamic strains that are intentionally induced to cause sensor drift. The actively stabilized embedded fiber optic Fabry-Perot sensor is also shown to have sufficient sensitivity to detect ultrasound that is generated in the interior of a structure by means of a high-power optical fiber that pipes energy from a pulsed laser to an embedded generator of ultrasound.

Ultrasonic Ranging System With Increased Resolution

Science.gov (United States)

Meyer, William E.; Johnson, William G.

1987-01-01

Master-oscillator frequency increased. Ultrasonic range-measuring system with 0.1-in. resolution provides continuous digital display of four distance readings, each updated four times per second. Four rangefinder modules in system are modified versions of rangefinder used for automatic focusing in commercial series of cameras. Ultrasonic pulses emitted by system innocuous to both people and equipment. Provides economical solutions to such distance-measurement problems as posed by boats approaching docks, truck backing toward loading platform, runway-clearance readout for tail of airplane with high angle attack, or burglar alarm.

Comparative study between ultrahigh spatial frequency algorithm and high spatial frequency algorithm in high-resolution CT of the lungs

International Nuclear Information System (INIS)

Oh, Yu Whan; Kim, Jung Kyuk; Suh, Won Hyuck

1994-01-01

To date, the high spatial frequency algorithm (HSFA) which reduces image smoothing and increases spatial resolution has been used for the evaluation of parenchymal lung diseases in thin-section high-resolution CT. In this study, we compared the ultrahigh spatial frequency algorithm (UHSFA) with the high spatial frequency algorithm in the assessment of thin section images of the lung parenchyma. Three radiologists compared the UHSFA and HSFA on identical CT images in a line-pair resolution phantom, one lung specimen, 2 patients with normal lung and 18 patients with abnormal lung parenchyma. Scanning of a line-pair resolution phantom demonstrated no difference in resolution between two techniques but it showed that outer lines of the line pairs with maximal resolution looked thicker on UHSFA than those on HSFA. Lung parenchymal detail with UHSFA was judged equal or superior to HSFA in 95% of images. Lung parenchymal sharpness was improved with UHSFA in all images. Although UHSFA resulted in an increase in visible noise, observers did not found that image noise interfered with image interpretation. The visual CT attenuation of normal lung parenchyma is minimally increased in images with HSFA. The overall visual preference of the images reconstructed on UHSFA was considered equal to or greater than that of those reconstructed on HSFA in 78% of images. The ultrahigh spatial frequency algorithm improved the overall visual quality of the images in pulmonary parenchymal high-resolution CT

Analysis of Ultrasonic Transmitted Signal for Apple using Wavelet Transform

International Nuclear Information System (INIS)

Kim, Ki Bok; Lee, Sang Dae; Choi, Man Yong; Kim, Man Soo

2005-01-01

This study was conducted to analyze the ultrasonic transmitted signal for apple using wavelet transform. Fruit consists of nonlinear visco-elastic properties such as flesh, an ovary and rind and lienee most ultrasonic wave is attenuated and its frequency is shifted during passing the fruit. Thus it is not easy to evaluate the internal quality of the fruit using typical ultrasonic parameters such as wave velocity, attenuation, and frequency spectrum. The discrete wavelet transform was applied to the ultrasonic transmitted signal for apple. The magnitude of the first peak frequency of the wavelet basis from the ultrasonic transmitted signal showed a close correlation to the storage time of apple

Method and apparatus to characterize ultrasonically reflective contrast agents

Science.gov (United States)

Pretlow, Robert A., III (Inventor)

1993-01-01

A method and apparatus for characterizing the time and frequency response of an ultrasonically reflective contrast agent is disclosed. An ultrasonically reflective contrast agent is injected, under constant pressure, into a fluid flowing through a pump flow circuit. The fluid and the ultrasonically reflective contrast agent are uniformly mixed in a mixing chamber, and the uniform mixture is passed through a contrast agent chamber. The contrast agent chamber is acoustically and axially interposed between an ultrasonic transducer chamber and an acoustic isolation chamber. A pulse of ultrasonic energy is transmitted into the contrast agent chamber from the ultrasonic transducer chamber. An echo waveform is received from the ultrasonically reflective contrast agent, and it is analyzed to determine the time and frequency response of the ultrasonically reflective contrast agent.

Ozone production in a dielectric barrier discharge with ultrasonic irradiation

DEFF Research Database (Denmark)

Drews, Joanna Maria; Kusano, Yukihiro; Leipold, Frank

2011-01-01

Ozone production has been investigated using an atmospheric pressure dielectric barrier discharge in pure O2 at room temperature with and without ultrasonic irradiation. It was driven at a frequency of either 15 kHz or 40 kHz. The ozone production was highly dependent on the O2 flow rate and the ......Ozone production has been investigated using an atmospheric pressure dielectric barrier discharge in pure O2 at room temperature with and without ultrasonic irradiation. It was driven at a frequency of either 15 kHz or 40 kHz. The ozone production was highly dependent on the O2 flow rate...

Frequency-locked pulse sequencer for high-frame-rate monochromatic tissue motion imaging.

Science.gov (United States)

Azar, Reza Zahiri; Baghani, Ali; Salcudean, Septimiu E; Rohling, Robert

2011-04-01

To overcome the inherent low frame rate of conventional ultrasound, we have previously presented a system that can be implemented on conventional ultrasound scanners for high-frame-rate imaging of monochromatic tissue motion. The system employs a sector subdivision technique in the sequencer to increase the acquisition rate. To eliminate the delays introduced during data acquisition, a motion phase correction algorithm has also been introduced to create in-phase displacement images. Previous experimental results from tissue- mimicking phantoms showed that the system can achieve effective frame rates of up to a few kilohertz on conventional ultrasound systems. In this short communication, we present a new pulse sequencing strategy that facilitates high-frame-rate imaging of monochromatic motion such that the acquired echo signals are inherently in-phase. The sequencer uses the knowledge of the excitation frequency to synchronize the acquisition of the entire imaging plane to that of an external exciter. This sequencing approach eliminates any need for synchronization or phase correction and has applications in tissue elastography, which we demonstrate with tissue-mimicking phantoms. © 2011 IEEE

Effects of surface-mapping corrections and synthetic-aperture focusing techniques on ultrasonic imaging

International Nuclear Information System (INIS)

Barna, B.A.; Johnson, J.A.

1981-01-01

Improvements in ultrasonic imaging that can be obtained using algorithms that map the surface of targets are evaluated. This information is incorporated in the application of synthetic-aperture focusing techniques which also have the potential to improve image resolution. Images obtained using directed-beam (flat) transducers and the focused transducers normally used for synthetic-aperture processing are quantitatively compared by using no processing, synthetic-aperture processing with no corrections for surface variations, and synthetic-aperture processing with surface mapping. The unprocessed images have relatively poor lateral resolutions because echoes from two adjacent reflectors show interference effects which prevent their identification even if the spacing is larger than the single-hole resolution. The synthetic-aperture-processed images show at least a twofold improvement in lateral resolution and greatly reduced interference effects in multiple-hole images compared to directed-beam images. Perhaps more importantly, in images of test blocks with substantial surface variations portions of the image are displaced from their actual positions by several wavelengths. To correct for this effect an algorithm has been developed for calculating the surface variations. The corrected images produced using this algorithm are accurate within the experimental error. In addition, the same algorithm, when applied to the directed-beam data, produced images that are not only accurately positioned, but that also have a resolution comparable to conventional synthetic-aperture-processed images obtained from focused-transducer data. This suggests that using synthetic-aperture processing on the type of data normally collected during directed-beam ultrasonic inspections would eliminate the need to rescan for synthetic-aperture enhancement

Adaptive ultrasonic imaging with the total focusing method for inspection of complex components immersed in water

Science.gov (United States)

Le Jeune, L.; Robert, S.; Dumas, P.; Membre, A.; Prada, C.

2015-03-01

In this paper, we propose an ultrasonic adaptive imaging method based on the phased-array technology and the synthetic focusing algorithm Total Focusing Method (TFM). The general principle is to image the surface by applying the TFM algorithm in a semi-infinite water medium. Then, the reconstructed surface is taken into account to make a second TFM image inside the component. In the surface reconstruction step, the TFM algorithm has been optimized to decrease computation time and to limit noise in water. In the second step, the ultrasonic paths through the reconstructed surface are calculated by the Fermat's principle and an iterative algorithm, and the classical TFM is applied to obtain an image inside the component. This paper presents several results of TFM imaging in components of different geometries, and a result obtained with a new technology of probes equipped with a flexible wedge filled with water (manufactured by Imasonic).

Ultrasonic Resonance Spectroscopy of Composite Rims for Flywheel Rotors

Science.gov (United States)

Harmon, Laura M.; Baaklini, George Y.

2002-01-01

Flywheel energy storage devices comprising multilayered composite rotor systems are being studied extensively for utilization in the International Space Station. These composite material systems were investigated with a recently developed ultrasonic resonance spectroscopy technique. The ultrasonic system employs a continuous swept-sine waveform and performs a fast Fourier transform (FFT) on the frequency response spectrum. In addition, the system is capable of equalizing the amount of energy at each frequency. Equalization of the frequency spectrum, along with interpretation of the second FFT, aids in the evaluation of the fundamental frequency. The frequency responses from multilayered material samples, with and without known defects, were analyzed to assess the capabilities and limitations of this nondestructive evaluation technique for material characterization and defect detection. Amplitude and frequency changes were studied from ultrasonic responses of thick composite rings and a multiring composite rim. A composite ring varying in thickness was evaluated to investigate the full thickness resonance. The frequency response characteristics from naturally occurring voids in a composite ring were investigated. Ultrasonic responses were compared from regions with and without machined voids in a composite ring and a multiring composite rim. Finally, ultrasonic responses from the multiring composite rim were compared before and after proof spin testing to 63,000 rpm.

3D Tendon Strain Estimation Using High-frequency Volumetric Ultrasound Images: A Feasibility Study.

Science.gov (United States)

Carvalho, Catarina; Slagmolen, Pieter; Bogaerts, Stijn; Scheys, Lennart; D'hooge, Jan; Peers, Koen; Maes, Frederik; Suetens, Paul

2018-03-01

Estimation of strain in tendons for tendinopathy assessment is a hot topic within the sports medicine community. It is believed that, if accurately estimated, existing treatment and rehabilitation protocols can be improved and presymptomatic abnormalities can be detected earlier. State-of-the-art studies present inaccurate and highly variable strain estimates, leaving this problem without solution. Out-of-plane motion, present when acquiring two-dimensional (2D) ultrasound (US) images, is a known problem and may be responsible for such errors. This work investigates the benefit of high-frequency, three-dimensional (3D) US imaging to reduce errors in tendon strain estimation. Volumetric US images were acquired in silico, in vitro, and ex vivo using an innovative acquisition approach that combines the acquisition of 2D high-frequency US images with a mechanical guided system. An affine image registration method was used to estimate global strain. 3D strain estimates were then compared with ground-truth values and with 2D strain estimates. The obtained results for in silico data showed a mean absolute error (MAE) of 0.07%, 0.05%, and 0.27% for 3D estimates along axial, lateral direction, and elevation direction and a respective MAE of 0.21% and 0.29% for 2D strain estimates. Although 3D could outperform 2D, this does not occur in in vitro and ex vivo settings, likely due to 3D acquisition artifacts. Comparison against the state-of-the-art methods showed competitive results. The proposed work shows that 3D strain estimates are more accurate than 2D estimates but acquisition of appropriate 3D US images remains a challenge.

Continuous ultrasonic waves to detect steam bubbles in water under high pressure

Energy Technology Data Exchange (ETDEWEB)

Hulshof, H J.M.; Schurink, F

1985-01-01

Steam in the recirculation circuit of boilers may lead to unacceptable high thermal loads on the evaporator tubes. The ability to detect steam in the recirculation circuit during process transients is therefore important. A simple detector using continuous ultrasonic waves and able to detect bubbles in water contained in steel tubes is described in this paper. The variation of the transmitted wave caused by the bubbles was determined by demodulation. The results have met the objectives set for cold water with air bubbles. A clear indication of the presence of steam bubbles was found in fast-flowing hot water in a steel tube with a diameter of 60 mm. A change in the low-frequency region of the modulation was the only indication of the presence of steam bubbles in the large-diameter downcomer of the water-separator drum of a boiler in an electrical power plant. Possible causes of the differences in the results obtained are discussed on the basis of differences in bubble sizes and in focusing and reflection of the ultrasonic waves. (orig.). 11 refs.; 10 figs.

Continuous ultrasonic waves to detect steam bubbles in water under high pressure

International Nuclear Information System (INIS)

Hulshof, H.J.M.; Schurink, F.

1985-01-01

Steam in the recirculation circuit of boilers may lead to unacceptable high thermal loads on the evaporator tubes. The ability to detect steam in the recirculation circuit during process transients is therefore important. A simple detector using continuous ultrasonic waves and able to detect bubbles in water contained in steel tubes is described in this paper. The variation of the transmitted wave caused by the bubbles was determined by demodulation. The results have met the objectives set for cold water with air bubbles. A clear indication of the presence of steam bubbles was found in fast-flowing hot water in a steel tube with a diameter of 60 mm. A change in the low-frequency region of the modulation was the only indication of the presence of steam bubbles in the large-diameter downcomer of the water-separator drum of a boiler in an electrical power plant. Possible causes of the differences in the results obtained are discussed on the basis of differences in bubble sizes and in focusing and reflection of the ultrasonic waves. (orig.)

Microscopic theory of ultrasonic attenuation in high-Tc superconductors in normal state

International Nuclear Information System (INIS)

Bishoyi, K.C.; Rout, G.C.; Behera, S.N.

2001-01-01

The mechanism of the ultrasonic attenuation in high temperature superconductors is not yet studied thoroughly both experimentally and theoretically. A microscopic theoretical model is proposed here to study the attenuation in the electron doped and hole doped compounds like L 2-x M x CuO 4 (L=La,Nd; M=Sr,Ca,Ce). The model Hamiltonian contains the staggered magnetic field in the d-electrons of copper, the doped f-electrons term and the hybridisation between d- and f-electrons. The electron-phonon interaction arises due to the volume strain dependence of the hybridisation. The phonon Green's function is calculated by equations of motion of Zubarev technique. The temperature dependence of the ultrasonic attenuation coefficient (α) is calculated from the imaginary part of the phonon self energy and the velocity of sound in the dynamic and long wavelength limit. The dimensionless parameters involved in the calculations are the electron-phonon coupling (g), staggered magnetic field (h) , hybridization (υ), position of the f-level (d), frequency (ω), and temperature (t). The results are discussed. (author)

Log response of ultrasonic imaging and its significance for deep mineral prospecting of scientific drilling borehole-2 in Nanling district, China

International Nuclear Information System (INIS)

Xiao, Kun; Zou, Changchun; Xiang, Biao; Yue, Xuyuan; Zhou, Xinpeng; Li, Jianguo; Zhao, Bin

2014-01-01

The hole NLSD-2, one of the deepest scientific drilling projects in the metallic ore districts of China, is the second scientific drilling deep hole in the Nanling district. Its ultimate depth is 2012.12 m. This hole was created through the implementation of continuous coring, and the measuring of a variety of geophysical well logging methods was performed over the course of the drilling process. This paper analyzes the characteristic responses of the fracture and fractured zone by ultrasonic imaging log data, and characterizes various rules of fracture parameters which change according to drilling depth. It then discusses the denotative meaning of the log results of polymetallic mineralization layers. The formation fractures develop most readily in a depth of 100∼200 m, 600∼850 m and 1450∼1550 m of the hole NLSD-2, and high angle fractures develop most prominently. The strike direction of the fractures is mainly NW-SE, reflecting the orientation of maximum horizontal principal stress. For the polymetallic mineralization layer that occurred in the fractured zone, the characteristic response of ultrasonic imaging log is a wide dark zone, and the characteristic responses of conventional logs displayed high polarizability, high density, high acoustic velocity and low resistivity. All the main polymetallic mineralization layers are developed in fractures or fractured zones, and the fractures and fractured zones can be identified by an ultrasonic imaging log, thus the log results indirectly indicate the occurrence of polymetallic mineralization layers. Additionally, the relationship between the dip direction of fractures and the well deviation provides guidance for straightening of the drilling hole. (paper)

Ultrasonic fingerprint sensor using a piezoelectric micromachined ultrasonic transducer array integrated with complementary metal oxide semiconductor electronics

Energy Technology Data Exchange (ETDEWEB)

Lu, Y.; Fung, S.; Wang, Q.; Horsley, D. A. [Berkeley Sensor and Actuator Center, University of California, Davis, 1 Shields Avenue, Davis, California 95616 (United States); Tang, H.; Boser, B. E. [Berkeley Sensor and Actuator Center, University of California, Berkeley, California 94720 (United States); Tsai, J. M.; Daneman, M. [InvenSense, Inc., 1745 Technology Drive, San Jose, California 95110 (United States)

2015-06-29

This paper presents an ultrasonic fingerprint sensor based on a 24 × 8 array of 22 MHz piezoelectric micromachined ultrasonic transducers (PMUTs) with 100 μm pitch, fully integrated with 180 nm complementary metal oxide semiconductor (CMOS) circuitry through eutectic wafer bonding. Each PMUT is directly bonded to a dedicated CMOS receive amplifier, minimizing electrical parasitics and eliminating the need for through-silicon vias. The array frequency response and vibration mode-shape were characterized using laser Doppler vibrometry and verified via finite element method simulation. The array's acoustic output was measured using a hydrophone to be ∼14 kPa with a 28 V input, in reasonable agreement with predication from analytical calculation. Pulse-echo imaging of a 1D steel grating is demonstrated using electronic scanning of a 20 × 8 sub-array, resulting in 300 mV maximum received amplitude and 5:1 contrast ratio. Because the small size of this array limits the maximum image size, mechanical scanning was used to image a 2D polydimethylsiloxane fingerprint phantom (10 mm × 8 mm) at a 1.2 mm distance from the array.

A flow meter for ultrasonically measuring the flow velocity of fluids

DEFF Research Database (Denmark)

2015-01-01

The invention regards a flow meter for ultrasonically measuring the flow velocity of fluids comprising a duct having a flow channel with an internal cross section comprising variation configured to generate at least one acoustic resonance within the flow channel for a specific ultrasonic frequency......, and at least two transducers for generating and sensing ultrasonic pulses, configured to transmit ultrasonic pulses at least at said specific ultrasonic frequency into the flow channel such that the ultrasonic pulses propagate through a fluid flowing in the flow channel, wherein the flow meter is configured...

Application of acoustical holography for construction shadow images in ultrasonic testing

International Nuclear Information System (INIS)

Kutzner, J.; Zimpfer, J.

1977-01-01

The full-scale, three-dimensional presentation of material defects by means of acoustical holography is limited on the one hand by an insufficient resolving power in depth of the procedure and, on the other hand, by the fact that the defects of the material to be examined often reflect mirror-like. Examined is the possible range of reducing these limitations by means of constructing shadow images of defects in ultrasonic testing without - as it is usually done - reconstructing the sonic field reflected by the flow but reconstructing the sonic field diffracted at the flow by means of acoustical holography. It has been shown that acoustical holography, during which the amplitude information is always analyzed as well as - on principle - the phase information, improves the efficiency of ultrasonic testing to a large extent. (orig.) [de

Ultrasonic decontamination robot

International Nuclear Information System (INIS)

Patenaude, R.S.

1984-01-01

An ultrasonic decontamination robot removes radioactive contamination from the internal surface of the inlet and outlet headers, divider plate, tube sheet, and lower portions of tubes of a nuclear power plant steam generator. A programmable microprocessor controller guides the movement of a robotic arm mounted in the header manway. An ultrasonic transducer having a solvent delivery subsystem through which ultrasonic action is achieved is moved by the arm over the surfaces. A solvent recovery suction tube is positioned within the header to remove solvent therefrom while avoiding interference with the main robotic arm. The solvent composition, temperature, pressure, viscosity, and purity are controlled to optimize the ultrasonic scrubbing action. The ultrasonic transducer is controlled at a power density, frequency, and on-off mode cycle such as to optimize scrubbing action within the range of transducer-to-surface distance and solvent layer thickness selected for the particular conditions encountered. Both solvent and transducer control actions are optimized by the programmable microprocessor. (author)

Monitoring of corrosion damage using high-frequency guided ultrasonic waves

OpenAIRE

Chew, D.; Fromme, P.

2014-01-01

Due to adverse environmental conditions corrosion can develop during the life cycle of industrial structures, e.g., offshore oil platforms, ships, and desalination plants. Both pitting corrosion and generalized corrosion leading to wall thickness loss can cause the degradation of the integrity and load bearing capacity of the structure. Structural health monitoring of corrosion damage in difficult to access areas can in principle be achieved using high frequency guided waves propagating along...

Automatic Quadcopter Control Avoiding Obstacle Using Camera with Integrated Ultrasonic Sensor

Science.gov (United States)

Anis, Hanafi; Haris Indra Fadhillah, Ahmad; Darma, Surya; Soekirno, Santoso

2018-04-01

Automatic navigation on the drone is being developed these days, a wide variety of types of drones and its automatic functions. Drones used in this study was an aircraft with four propellers or quadcopter. In this experiment, image processing used to recognize the position of an object and ultrasonic sensor used to detect obstacle distance. The method used to trace an obsctacle in image processing was the Lucas-Kanade-Tomasi Tracker, which had been widely used due to its high accuracy. Ultrasonic sensor used to complement the image processing success rate to be fully detected object. The obstacle avoidance system was to observe at the program decisions from some obstacle conditions read by the camera and ultrasonic sensors. Visual feedback control based PID controllers are used as a control of drones movement. The conclusion of the obstacle avoidance system was to observe at the program decisions from some obstacle conditions read by the camera and ultrasonic sensors.

Enhancing Plasma Surface Modification using high Intensity and high Power Ultrasonic Acoustic Waves

DEFF Research Database (Denmark)

2010-01-01

high intensity and high power acoustic waves (102) by at least one ultrasonic high intensity and high power acoustic wave generator (101 ), wherein the ultrasonic acoustic waves are directed to propagate towards said surface (314) of the object (100) so that a laminar boundary layer (313) of a gas...... or a mixture of gases (500) flow in contact with said solid object (100) is thinned or destructed for at least a part of said surface (314). In this way, the plasma can more efficiently access and influence the surface of the solid object to be treated by the plasma, which speeds the process time up...

Determination of the apparent porosity level of refractory concrete during a sintering process using an ultrasonic pulse velocity technique and image analysis

Directory of Open Access Journals (Sweden)

LJUBICA M. PAVLOVIĆ

2010-03-01

Full Text Available Concrete which undergoes a thermal treatment before (pre-casted concrete blocks and during (concrete embedded in-situ its life-service can be applied in plants operating at high temperature and as thermal insulation. Sintering is a process which occurs within a concrete structure in such conditions. Progression of sintering process can be monitored by the change of the porosity parameters determined with a nondestructive test method - ultrasonic pulse velocity and computer program for image analysis. The experiment has been performed on the samples of corundum and bauxite concrete composites. The apparent porosity of the samples thermally treated at 110, 800, 1000, 1300 and 1500 C was primary investigated with a standard laboratory procedure. Sintering parameters were calculated from the creep testing. The loss of strength and material degradation occurred in concrete when it was subjected to the increased temperature and a compressive load. Mechanical properties indicate and monitor changes within microstructure. The level of surface deterioration after the thermal treatment was determined using Image Pro Plus program. Mechanical strength was estimated using ultrasonic pulse velocity testing. Nondestructive ultrasonic mea¬surement was used as a qualitative description of the porosity change in specimens which is the result of the sintering process. The ultrasonic pulse velocity technique and image analysis proved to be reliable methods for monitoring of micro-structural change during the thermal treatment and service life of refractory concrete.

Ultrasonic testing of austenitic stainless steel welds

International Nuclear Information System (INIS)

Nishino, Shunichi; Hida, Yoshio; Yamamoto, Michio; Ando, Tomozumi; Shirai, Tasuku.

1982-05-01

Ultrasonic testing of austenitic stainless steel welds has been considered difficult because of the high noise level and remarkable attenuation of ultrasonic waves. To improve flaw detectability in this kind of steel, various inspection techniques have been studied. A series of tests indicated: (1) The longitudinal angle beam transducers newly developed during this study can detect 4.8 mm dia. side drilled holes in dissimilar metal welds (refraction angle: 55 0 from SUS side, 45 0 from CS side) and in cast stainless steel welds (refraction angle: 45 0 , inspection frequency: 1 MHz). (2) Cracks more than 5% t in depth in the heat affected zones of fine-grain stainless steel pipe welds can be detected by the 45 0 shear wave angle beam method (inspection frequency: 2 MHz). (3) The pattern recognition method using frequency analysis technology was presumed useful for discriminating crack signals from spurious echoes. (author)

Wavelet Analysis of Ultrasonic Echo Waveform and Application to Nondestructive Evaluation

International Nuclear Information System (INIS)

Park, Ik Keun; Park, Un Su; Ahn, Hyung Keun; Kwun, Sook In; Byeon, Jai Won

2000-01-01

Recently, advanced signal analysis which is called 'time-frequency analysis' has been used widely in nondestructive evaluation applications. Wavelet transform(WT) and Wigner Distribution are the most advanced techniques for processing signals with time-varying spectra. Wavelet analysis method is an attractive technique for evaluation of material characterization nondestructively. Wavelet transform is applied to the time-frequency analysis of ultrasonic echo waveform obtained by an ultrasonic pulse-echo technique. In this study, the feasibility of noise suppression of ultrasonic flaw signal and frequency-dependent ultrasonic group velocity and attenuation coefficient using wavelet analysis of ultrasonic echo waveform have been verified experimentally. The Gabor function is adopted the analyzing wavelet. The wavelet analysis shows that the variations of ultrasonic group velocity and attenuation coefficient due to the change of material characterization can be evaluated at each frequency. Furthermore, to assure the enhancement of detectability and new sizing performance, both computer simulated results and experimental measurements using wavelet signal processing are used to demonstrate the effectiveness of the noise suppression of ultrasonic flaw signal obtained from austenitic stainless steel weld including EDM notch

A high-frequency transimpedance amplifier for CMOS integrated 2D CMUT array towards 3D ultrasound imaging.

Science.gov (United States)

Huang, Xiwei; Cheong, Jia Hao; Cha, Hyouk-Kyu; Yu, Hongbin; Je, Minkyu; Yu, Hao

2013-01-01

One transimpedance amplifier based CMOS analog front-end (AFE) receiver is integrated with capacitive micromachined ultrasound transducers (CMUTs) towards high frequency 3D ultrasound imaging. Considering device specifications from CMUTs, the TIA is designed to amplify received signals from 17.5MHz to 52.5MHz with center frequency at 35MHz; and is fabricated in Global Foundry 0.18-µm 30-V high-voltage (HV) Bipolar/CMOS/DMOS (BCD) process. The measurement results show that the TIA with power-supply 6V can reach transimpedance gain of 61dBΩ and operating frequency from 17.5MHz to 100MHz. The measured input referred noise is 27.5pA/√Hz. Acoustic pulse-echo testing is conducted to demonstrate the receiving functionality of the designed 3D ultrasound imaging system.

Hardware Developments of an Ultrasonic Tomography Measurement System

Directory of Open Access Journals (Sweden)

Hudabiyah ARSHAD AMARI

2010-01-01

Full Text Available This research provides new technique in ultrasonic tomography by using ultrasonic transceivers instead of using separate transmitter-receiver pair. The numbers of sensors or transducers used to acquire data plays an important role to generate high resolution tomography images. The configuration of these sensors is a crucial factor in the efficiency of data acquisition. Instead of using common separated transmitter – receiver, an alternative approach has been taken to use dual functionality ultrasonic transceiver. A prototype design of sensor’s jig that will hold 16 transceivers of 14.1mm has been design. Transmission-mode approach with fan beam technique has been used for sensing the flow of gas, liquid and solid. This paper also explains the circuitry designs for the Ultrasonic Tomography System.

A study on laser-based ultrasonic technique by the use of guided wave tomographic imaging

Energy Technology Data Exchange (ETDEWEB)

Park, Junpil, E-mail: jpp@pusan.ac.kr; Lim, Juyoung, E-mail: jpp@pusan.ac.kr [Graduate school, School of Mechanical Engineering, Pusan National University (Korea, Republic of); Cho, Younho [School of Mechanical Engineering, Pusan National University (Korea, Republic of); Krishnaswamy, Sridhar [Center for Quality Engineering and Failure Prevention, Northwestern University, Evanston, IL (United States)

2015-03-31

Guided wave tests are impractical for investigating specimens with limited accessibility and coarse surfaces or geometrically complicated features. A non-contact setup with a laser ultrasonic transmitter and receiver is the classic attractive for guided wave inspection. The present work was done to develop a non-contact guided-wave tomography technique by laser ultrasonic technique in a plate-like structure. A method for Lam wave generation and detection in an aluminum plate with a pulse laser ultrasonic transmitter and a Michelson interferometer receiver has been developed. In the images obtained by laser scanning, the defect shape and area showed good agreement with the actual defect. The proposed approach can be used as a non-contact-based online inspection and monitoring technique.

High Resolution Ultrasonic Method for 3D Fingerprint Representation in Biometrics

Science.gov (United States)

Maev, R. Gr.; Bakulin, E. Y.; Maeva, E. Y.; Severin, F. M.

Biometrics is an important field which studies different possible ways of personal identification. Among a number of existing biometric techniques fingerprint recognition stands alone - because very large database of fingerprints has already been acquired. Also, fingerprints are an important evidence that can be collected at a crime scene. Therefore, of all automated biometric techniques, especially in the field of law enforcement, fingerprint identification seems to be the most promising. Ultrasonic method of fingerprint imaging was originally introduced over a decade as the mapping of the reflection coefficient at the interface between the finger and a covering plate and has shown very good reliability and free from imperfections of previous two methods. This work introduces a newer development of the ultrasonic fingerprint imaging, focusing on the imaging of the internal structures of fingerprints (including sweat pores) with raw acoustic resolution of about 500 dpi (0.05 mm) using a scanning acoustic microscope to obtain images and acoustic data in the form of 3D data array. C-scans from different depths inside the fingerprint area of fingers of several volunteers were obtained and showed good contrast of ridges-and-valleys patterns and practically exact correspondence to the standard ink-and-paper prints of the same areas. Important feature reveled on the acoustic images was the clear appearance of the sweat pores, which could provide additional means of identification.

Role of ultrasonic irradiation on transesterification of palm oil using calcium oxide as a solid base catalyst

International Nuclear Information System (INIS)

Poosumas, Jutipong; Ngaosuwan, Kanokwan; Quitain, Armando T.; Assabumrungrat, Suttichai

2016-01-01

Highlights: • Transesterification of palm oil using a circulated continuous flow ultrasonic reactor. • Heterogeneous system using CaO as catalyst. • Effects of ultrasonic frequency and power, and catalyst reusability were considered. • A single high frequency and high intensity irradiation is favorable for heterogeneous system. - Abstract: Biodiesel production from transesterification of palm oil using a circulated continuous flow ultrasonic reactor was investigated. Transesterification was carried out at 60 °C, 1 atm and a methanol-to-oil molar ratio of 9:1. The highest reaction rate was achieved at the catalyst loading of 2 wt%, and biodiesel yield constantly increased until transesterification equilibrium (about 80%) was reached. A higher ultrasonic frequency (50 kHz) promoted the heterogeneously catalyzed transesterification of refined palm oil, because the three-phase system (packed solid catalyst, methanol and oil) required more spatial distribution by ultrasonic irradiation. Moreover, the highest ultrasonic power also provided highest transesterification rate and biodiesel yield due to cavitation activity enhancement. Reusability of calcium oxide catalysts was also investigated, and results showed that this can be reused to provide high biodiesel yield for at least three operations with slight decrease in the rate of reaction due to counter balance effect of organic compounds deposition on the catalyst surface. The results from this study can be a basis for scaling up of the process to industrial scale.

Ultrasonic Nanobubbles Carrying Anti-PSMA Nanobody: Construction and Application in Prostate Cancer-Targeted Imaging.

Directory of Open Access Journals (Sweden)

Xiaozhou Fan

Full Text Available To facilitate prostate cancer imaging using targeted molecules, we constructed ultrasonic nanobubbles coupled with specific anti-PSMA (prostate specific membrane antigen nanobodies, and evaluated their in vitro binding capacity and in vivo imaging efficacy. The "targeted" nanobubbles, which were constructed via a biotin-streptavidin system, had an average diameter of 487.60 ± 33.55 nm and carried the anti-PSMA nanobody as demonstrated by immunofluorescence. Microscopy revealed targeted binding of nanobubbles in vitro to PSMA-positive cells. Additionally, ultrasonography indicators of nanobubble imaging (including arrival time, peak time, peak intensity and enhanced duration were evaluated for the ultrasound imaging in three kinds of animal xenografts (LNCaP, C4-2 and MKN45, and showed that these four indicators of targeted nanobubbles exhibited significant differences from blank nanobubbles. Therefore, this study not only presents a novel approach to target prostate cancer ultrasonography, but also provides the basis and methods for constructing small-sized and high-efficient targeted ultrasound nanobubbles.

Nonlinear piezoelectricity in PZT ceramics for generating ultrasonic phase conjugate waves

Science.gov (United States)

Yamamoto; Kokubo; Sakai; Takagi

2000-03-01

We have succeeded in the generation of acoustic phase conjugate waves with nonlinear PZT piezoelectric ceramics and applied them to ultrasonic imaging systems. Our aim is to make a phase conjugator with 100% efficiency. For this purpose, it is important to clarify the mechanism of acoustic phase conjugation through nonlinear piezoelectricity. The process is explained by the parametric interaction via the third-order nonlinear piezoelectricity between the incident acoustic wave at angular frequency omega and the pump electric field at 2 omega. We solved the coupling equations including the third-ordered nonlinear piezoelectricity and theoretically derived the amplitude efficiency of the acoustic phase conjugation. We compared the efficiencies between the theoretical and experimental values for PZT ceramics with eight different compositions. Pb[(Zn1/3Nb2/3)(1 - x)Tix]O3 (X = 0.09, PZNT91/9) piezoelectric single crystals have been investigated for high-performance ultrasonic transducer application, because these have large piezoelectric constants, high electrical-mechanical coupling factors and high dielectric constants. We found that they have third-order nonlinear piezoelectric constants much larger than PZT and are hopeful that the material as a phase conjugator has over 100% efficiency.

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

Science.gov (United States)

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

Sampling phased array, a new technique for ultrasonic signal processing and imaging now available to industry

OpenAIRE

Verkooijen, J.; Bulavinov, A.

2008-01-01

Over the past 10 years the improvement in the field of microelectronics and computer engineering has led to significant advances in ultrasonic signal processing and image construction techniques that are currently being applied to non-destructive material evaluation. A new phased array technique, called "Sampling Phased Array" has been developed in the Fraunhofer Institute for non-destructive testing [1]. It realizes a unique approach of measurement and processing of ultrasonic signals. The s...

Fast ultrasonic visualisation under sodium. Application to the fast neutron reactors; Visualisation ultrasonore rapide sous sodium. application aux reacteurs a neutrons rapides

Energy Technology Data Exchange (ETDEWEB)

Imbert, Ch

1997-05-30

The fast ultrasonic visualization under sodium is in the programme of research and development on the inspection inside the fast neutron reactors. This work is about the development of a such system of fast ultrasonic imaging under sodium, in order to improve the existing visualization systems. This system is based on the principle of orthogonal imaging, it uses two linear antennas with an important dephasing having 128 piezo-composite elements of central frequency equal to 1.6 MHz. (N.C.)

Hardware Developments of an Ultrasonic Tomography Measurement System

OpenAIRE

Hudabiyah ARSHAD AMARI; Ruzairi ABDUL RAHIM; Mohd Hafiz FAZALUL RAHIMAN; Herlina ABDUL RAHIM; Muhammad Jaysuman PUSPPANATHAN

2010-01-01

This research provides new technique in ultrasonic tomography by using ultrasonic transceivers instead of using separate transmitter-receiver pair. The numbers of sensors or transducers used to acquire data plays an important role to generate high resolution tomography images. The configuration of these sensors is a crucial factor in the efficiency of data acquisition. Instead of using common separated transmitter – receiver, an alternative approach has been taken to use dual functionality ul...

Fundamentals of Medical Ultrasonics

CERN Document Server

Postema, Michiel

2011-01-01

This book sets out the physical and engineering principles of acoustics and ultrasound as used for medical applications. It covers the basics of linear acoustics, wave propagation, non-linear acoustics, acoustic properties of tissue, transducer components, and ultrasonic imaging modes, as well as the most common diagnostic and therapeutic applications. It offers students and professionals in medical physics and engineering a detailed overview of the technical aspects of medical ultrasonic imaging, whilst serving as a reference for clinical and research staff.

Bubble dynamics under acoustic excitation with multiple frequencies

International Nuclear Information System (INIS)

Zhang, Y N; Zhang, Y N; Li, S C

2015-01-01

Because of its magnificent mechanical and chemical effects, acoustic cavitation plays an important role in a broad range of biomedical, chemical and mechanical engineering problems. Particularly, irradiation of the multiple frequency acoustic wave could enhance the effects of cavitation. The advantages of employment of multi-frequency ultrasonic field include decreasing the cavitation thresholds, promoting cavitation nuclei generation, increasing the mass transfer and improving energy efficiency. Therefore, multi-frequency ultrasonic systems are employed in a variety of applications, e.g., to enhance the intensity of sonoluminenscence, to increase efficiency of sonochemical reaction, to improve the accuracy of ultrasound imaging and the efficiency of tissue ablation. Compared to single-frequency systems, a lot of new features of bubble dynamics exist in multi-frequency systems, such as special properties of oscillating bubbles, unique resonances in the bubble response curves, and unusual chaotic behaviours. In present paper, the underlying mechanisms of the cavitation effects under multi-frequency acoustical excitation are also briefly introduced

Feasibility on Ultrasonic Velocity using Contact and Non-Contact Nondestructive Techniques for Carbon/Carbon Composites

Science.gov (United States)

Im, K. H.; Chang, M.; Hsu, D. K.; Song, S. J.; Cho, H.; Park, J. W.; Kweon, Y. S.; Sim, J. K.; Yang, I. Y.

2007-03-01

Advanced materials are to be required to have specific functions associated with extremely environments. One of them is carbon/carbon(C/C) composite material, which has obvious advantages over conventional materials. The C/Cs have become to be utilized as parts of aerospace applications and its low density, high thermal conductivity and excellent mechanical properties at elevated temperatures make it an ideal material for aircraft brake disks. Because of permeation of coupling medium such as water, it is desirable to perform contact-less nondestructive evaluation to assess material properties and part homogeneity. In this work, a C/C composite material was characterized with non-contact and contact ultrasonic methods using a scanner with automatic-data acquisition function. Also through transmission mode was performed because of the main limitation for air-coupled transducers, which is the acoustic impedance mismatch between most materials and air. Especially ultrasonic images and velocities for C/C composite disk brake were compared and found to be consistent to some degree with the non-contact and contact ultrasonic measurement methods. Low frequency through-transmission scans based on both amplitude of the ultrasonic pulse was used for mapping out the material property inhomogeneity. Measured results were compared with those obtained by the dry-coupling ultrasonic UT system and through transmission method in immersion. Finally, feasibility has been found to measure and compare ultrasonic velocities of C/C composites with using the contact/noncontact peak-delay measurement method based on the pulse overlap method.

Enhancing gas-phase reaction in a plasma using high intensity and high power ultrasonic acoustic waves

DEFF Research Database (Denmark)

2010-01-01

is absorbed into said plasma (104), and where a sound pressure level of said generated ultrasonic high intensity and high power acoustic waves (102) is at least substantially 140 dB and where an acoustic power of said generated ultrasonic high intensity and high power acoustic waves (102); is at least...... substantially 100 W. In this way, a high sound intensity and power are obtained that efficiently enhances a gas-phase reaction in the plasma, which enhances the plasma process, e.g. enabling more efficient ozone or hydrogen generation using plasma in relation to reaction speed and/or obtained concentration......This invention relates to enhancing a gas-phase reaction in a plasma comprising: creating plasma (104) by at least one plasma source (106), and wherein that the method further comprises: generating ultrasonic high intensity and high power acoustic waves (102) having a predetermined amount...

Response of fiber Bragg gratings to longitudinal ultrasonic waves.

Science.gov (United States)

Minardo, Aldo; Cusano, Andrea; Bernini, Romeo; Zeni, Luigi; Giordano, Michele

2005-02-01

In the last years, fiber optic sensors have been widely exploited for several sensing applications, including static and dynamic strain measurements up to acoustic detection. Among these, fiber Bragg grating sensors have been indicated as the ideal candidate for practical structural health monitoring in light of their unique advantages over conventional sensing devices. Although this class of sensors has been successfully tested for static and low-frequency measurements, the identification of sensor performances for high-frequency detection, including acoustic emission and ultrasonic investigations, is required. To this aim, the analysis of feasibilty on the use of fiber Bragg grating sensors as ultrasonic detectors has been carried out. In particular, the response of fiber Bragg gratings subjected to the longitudinal ultrasonic (US) field has been theoretically and numerically investigated. Ultrasonic field interaction has been modeled, taking into account the direct deformation of the grating pitch combined with changes in local refractive index due to the elasto-optic effect. Numerical results, obtained for both uniform and Gaussian-apodized fiber Bragg gratings, show that the grating spectrum is strongly influenced by the US field in terms of shape and central wavelength. In particular, a key parameter affecting the grating response is the ratio between the US wavelength and the grating length. Normal operation characterized by changes in wavelength of undistorted Bragg peak is possible only for US wavelengths longer than the grating length. For US wavelengths approaching the grating length, the wavelength change is accompanied by subpeaks formation and main peak amplitude modulation. This effect can be attributed to the nonuniformity of the US perturbation along the grating length. At very high US frequencies, the grating is not sensitive any longer. The results of this analysis provide useful tools for the design of grating-based ultrasound sensors for

Capacitive micromachined ultrasonic transducers for medical imaging and therapy

International Nuclear Information System (INIS)

Khuri-Yakub, Butrus T; Oralkan, Ömer

2011-01-01

Capacitive micromachined ultrasonic transducers (CMUTs) have been subject to extensive research for the last two decades. Although they were initially developed for air-coupled applications, today their main application space is medical imaging and therapy. This paper first presents a brief description of CMUTs, their basic structure and operating principles. Our progression of developing several generations of fabrication processes is discussed with an emphasis on the advantages and disadvantages of each process. Monolithic and hybrid approaches for integrating CMUTs with supporting integrated circuits are surveyed. Several prototype transducer arrays with integrated front-end electronic circuits we developed and their use for 2D and 3D, anatomical and functional imaging, and ablative therapies are described. The presented results prove the CMUT as a micro-electro-mechanical systems technology for many medical diagnostic and therapeutic applications

Capacitive micromachined ultrasonic transducers for medical imaging and therapy.

Science.gov (United States)

Khuri-Yakub, Butrus T; Oralkan, Omer

2011-05-01

Capacitive micromachined ultrasonic transducers (CMUTs) have been subject to extensive research for the last two decades. Although they were initially developed for air-coupled applications, today their main application space is medical imaging and therapy. This paper first presents a brief description of CMUTs, their basic structure, and operating principles. Our progression of developing several generations of fabrication processes is discussed with an emphasis on the advantages and disadvantages of each process. Monolithic and hybrid approaches for integrating CMUTs with supporting integrated circuits are surveyed. Several prototype transducer arrays with integrated frontend electronic circuits we developed and their use for 2-D and 3-D, anatomical and functional imaging, and ablative therapies are described. The presented results prove the CMUT as a MEMS technology for many medical diagnostic and therapeutic applications.

Effect of zooming on texture features of ultrasonic images

Directory of Open Access Journals (Sweden)

Kyriacou Efthyvoulos

2006-01-01

Full Text Available Abstract Background Unstable carotid plaques on subjective, visual, assessment using B-mode ultrasound scanning appear as echolucent and heterogeneous. Although previous studies on computer assisted plaque characterisation have standardised B-mode images for brightness, improving the objective assessment of echolucency, little progress has been made towards standardisation of texture analysis methods, which assess plaque heterogeneity. The aim of the present study was to investigate the influence of image zooming during ultrasound scanning on textural features and to test whether or not resolution standardisation decreases the variability introduced. Methods Eighteen still B-mode images of carotid plaques were zoomed during carotid scanning (zoom factor 1.3 and both images were transferred to a PC and normalised. Using bilinear and bicubic interpolation, the original images were interpolated in a process of simulating off-line zoom using the same interpolation factor. With the aid of the colour-coded image, carotid plaques of the original, zoomed and two resampled images for each case were outlined and histogram, first order and second order statistics were subsequently calculated. Results Most second order statistics (21/25, 84% were significantly (p Conclusion Texture analysis of ultrasonic plaques should be performed under standardised resolution settings; otherwise a resolution normalisation algorithm should be applied.

Piston cylinder cell for high pressure ultrasonic pulse echo measurements

Energy Technology Data Exchange (ETDEWEB)

Kepa, M. W., E-mail: mkepa@staffmail.ed.ac.uk; Huxley, A. D. [SUPA, Centre for Science at Extreme Conditions and School of Physics and Astronomy, University of Edinburgh, Edinburgh EH9 3JZ (United Kingdom); Ridley, C. J.; Kamenev, K. V. [Centre for Science at Extreme Conditions and School of Engineering, University of Edinburgh, Edinburgh EH9 3FD (United Kingdom)

2016-08-15

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 UGe{sub 2}.

High temperature ultrasonic immersion measurements using a BS-PT based piezoelectric transducer without a delay line

Science.gov (United States)

Bilgunde, Prathamesh N.; Bond, Leonard J.

2018-04-01

Ultrasonic imaging is a key enabling technology required for in-service inspection of advanced sodium fast reactors at the hot stand-by operating mode (˜250C). Current work presents development of a single element, 2.4MHz, planar, ultrasonic immersion transducer for a potential application in ranging, inspection and imaging of the reactor components. The prototype immersion transducer is first tested in water for three thermal cycles up to 92C. The transducer is further evaluated for four thermal cycles in silicone oil, with total seven thermal cycles that exceeded operation period of 21 hours. Moreover, the preliminary data acquired for speed of sound in silicone oil indicates 24% reduction from 22C to 142C. Sensitivity of the ultrasonic transducer is also measured as a function of temperature and demonstrates the effect of multiple thermal cycles on the transducer components.

Corrosion monitoring using high-frequency guided waves

Science.gov (United States)

Fromme, P.

2016-04-01

Corrosion can develop due to adverse environmental conditions during the life cycle of a range of industrial structures, e.g., offshore oil platforms, ships, and desalination plants. Generalized corrosion leading to wall thickness loss can cause the reduction of the strength and thus degradation of the structural integrity. The monitoring of corrosion damage in difficult to access areas can be achieved using high frequency guided waves propagating along the structure from accessible areas. Using standard ultrasonic wedge transducers with single sided access to the structure, guided wave modes were selectively generated that penetrate through the complete thickness of the structure. The wave propagation and interference of the different guided wave modes depends on the thickness of the structure. Laboratory experiments were conducted for wall thickness reduction due to milling of the steel structure. From the measured signal changes due to the wave mode interference the reduced wall thickness was monitored. Good agreement with theoretical predictions was achieved. The high frequency guided waves have the potential for corrosion damage monitoring at critical and difficult to access locations from a stand-off distance.

Frequency dispersion of longitudinal ultrasonic velocity and attenuation in [001]c-poled 0.24Pb(In₁/₂Nb₁/₂O₃- 0.45Pb(Mg₁/₃Nb₂/₃)O₃-0.31PbTiO₃ single crystal.

Science.gov (United States)

Sun, Enwei; Cao, Wenwu; Han, Pengdi

2011-08-01

The frequency dispersion of ultrasonic velocity and attenuation in [001](c)-poled 0.24Pb(in(1/2)Nb(1/2))O(3)-0.45Pb(Mg(1/3)Nb(2/3))o(3)-0.31PbTio(3) (PIN-0.45PMN-0.31PT) ternary single crystal were measured by ultrasonic spectroscopy from 25 to 100 MHz for the longitudinal wave. It was found that the velocity has a linear relationship with the frequency f, but the attenuation has a quadratic relation with f. The attenuation and frequency dispersion of the ternary system are lower than that of the (1-x)Pb(Mg(1/3)Nb(2/3))O(3)-xPbTiO(3) (PMN-PT) binary system and the coercive field also increased by a factor of 2.5, hence, the ternary single system is superior to the corresponding binary single-crystal system for high-frequency and high-power transducer applications.

Interfacial Dynamics of Condensing Vapor Bubbles in an Ultrasonic Acoustic Field

Science.gov (United States)

Boziuk, Thomas; Smith, Marc; Glezer, Ari

2016-11-01

Enhancement of vapor condensation in quiescent subcooled liquid using ultrasonic actuation is investigated experimentally. The vapor bubbles are formed by direct injection from a pressurized steam reservoir through nozzles of varying characteristic diameters, and are advected within an acoustic field of programmable intensity. While kHz-range acoustic actuation typically couples to capillary instability of the vapor-liquid interface, ultrasonic (MHz-range) actuation leads to the formation of a liquid spout that penetrates into the vapor bubble and significantly increases its surface area and therefore condensation rate. Focusing of the ultrasonic beam along the spout leads to ejection of small-scale droplets from that are propelled towards the vapor liquid interface and result in localized acceleration of the condensation. High-speed video of Schlieren images is used to investigate the effects of the ultrasonic actuation on the thermal boundary layer on the liquid side of the vapor-liquid interface and its effect on the condensation rate, and the liquid motion during condensation is investigated using high-magnification PIV measurements. High-speed image processing is used to assess the effect of the actuation on the dynamics and temporal variation in characteristic scale (and condensation rate) of the vapor bubbles.

Wireless ultrasonic wavefield imaging via laser for hidden damage detection inside a steel box girder bridge

International Nuclear Information System (INIS)

An, Yun-Kyu; Song, Homin; Sohn, Hoon

2014-01-01

This paper presents a wireless ultrasonic wavefield imaging (WUWI) technique for detecting hidden damage inside a steel box girder bridge. The proposed technique allows (1) complete wireless excitation of piezoelectric transducers and noncontact sensing of the corresponding responses using laser beams, (2) autonomous damage visualization without comparing against baseline data previously accumulated from the pristine condition of a target structure and (3) robust damage diagnosis even for real structures with complex structural geometries. First, a new WUWI hardware system was developed by integrating optoelectronic-based signal transmitting and receiving devices and a scanning laser Doppler vibrometer. Next, a damage visualization algorithm, self-referencing f-k filter (SRF), was introduced to isolate and visualize only crack-induced ultrasonic modes from measured ultrasonic wavefield images. Finally, the performance of the proposed technique was validated through hidden crack visualization at a decommissioned Ramp-G Bridge in South Korea. The experimental results reveal that the proposed technique instantaneously detects and successfully visualizes hidden cracks even in the complex structure of a real bridge. (paper)

The effects of ultrasonic solidification on aluminum

OpenAIRE

Đorđević Slavko 1

2003-01-01

The effect of ultrasound on characteristics of solidified aluminum was shown. An ultrasonic head and ultrasonic system for modification was designed and applied to the crystallizing aluminum melt. The ultrasonic generator allows power of 50-500 W, amplitude of oscillations 10-100 um.m and the operating frequency of 25 kHz. Ultrasonic modification was done by ultrasound introduced from above into the melt. Microstructure photographs show decreasing of the grain size more than five times.

The effects of ultrasonic solidification on aluminum

Directory of Open Access Journals (Sweden)

Đorđević Slavko 1

2003-01-01

Full Text Available The effect of ultrasound on characteristics of solidified aluminum was shown. An ultrasonic head and ultrasonic system for modification was designed and applied to the crystallizing aluminum melt. The ultrasonic generator allows power of 50-500 W, amplitude of oscillations 10-100 um.m and the operating frequency of 25 kHz. Ultrasonic modification was done by ultrasound introduced from above into the melt. Microstructure photographs show decreasing of the grain size more than five times.

Measurement of a 3D Ultrasonic Wavefield Using Pulsed Laser Holographic Microscopy for Ultrasonic Nondestructive Evaluation

Directory of Open Access Journals (Sweden)

Xing Wang

2018-02-01

Full Text Available In ultrasonic array imaging, 3D ultrasonic wavefields are normally recorded by an ultrasonic piezo array transducer. Its performance is limited by the configuration and size of the array transducer. In this paper, a method based on digital holographic interferometry is proposed to record the 3D ultrasonic wavefields instead of the array transducer, and the measurement system consisting of a pulsed laser, ultrasonic excitation, and synchronization and control circuit is designed. A consecutive sequence of holograms of ultrasonic wavefields are recorded by the system. The interferograms are calculated from the recorded holograms at different time sequence. The amplitudes and phases of the transient ultrasonic wavefields are recovered from the interferograms by phase unwrapping. The consecutive sequence of transient ultrasonic wavefields are stacked together to generate 3D ultrasonic wavefields. Simulation and experiments are carried out to verify the proposed technique, and preliminary results are presented.

Tridimensional ultrasonic images analysis for the in service inspection of fast breeder reactors; Analyse d'images tridimensionnelles ultrasonores pour l'inspection en service des reacteurs a neutrons rapides

Energy Technology Data Exchange (ETDEWEB)

Dancre, M

1999-11-01

Tridimensional image analysis provides a set of methods for the intelligent extraction of information in order to visualize, recognize or inspect objects in volumetric images. In this field of research, we are interested in algorithmic and methodological aspects to extract surface visual information embedded in volume ultrasonic images. The aim is to help a non-acoustician operator, possibly the system itself, to inspect surfaces of vessel and internals in Fast Breeder Reactors (FBR). Those surfaces are immersed in liquid metal, what justifies the ultrasonic technology choice. We expose firstly a state of the art on the visualization of volume ultrasonic images, the methods of noise analysis, the geometrical modelling for surface analysis and finally curves and surfaces matching. These four points are then inserted in a global analysis strategy that relies on an acoustical analysis (echoes recognition), an object analysis (object recognition and reconstruction) and a surface analysis (surface defects detection). Few literature can be found on ultrasonic echoes recognition through image analysis. We suggest an original method that can be generalized to all images with structured and non-structured noise. From a technical point of view, this methodology applied to echoes recognition turns out to be a cooperative approach between morphological mathematics and snakes (active contours). An entropy maximization technique is required for volumetric data binarization. (author)

Crack detection and analyses using resonance ultrasonic vibrations in full-size crystalline silicon wafers

International Nuclear Information System (INIS)

Belyaev, A.; Polupan, O.; Dallas, W.; Ostapenko, S.; Hess, D.; Wohlgemuth, J.

2006-01-01

An experimental approach for fast crack detection and length determination in full-size solar-grade crystalline silicon wafers using a resonance ultrasonic vibrations (RUV) technique is presented. The RUV method is based on excitation of the longitudinal ultrasonic vibrations in full-size wafers. Using an external piezoelectric transducer combined with a high sensitivity ultrasonic probe and computer controlled data acquisition system, real-time frequency response analysis can be accomplished. On a set of identical crystalline Si wafers with artificially introduced periphery cracks, it was demonstrated that the crack results in a frequency shift in a selected RUV peak to a lower frequency and increases the resonance peak bandwidth. Both characteristics were found to increase with the length of the crack. The frequency shift and bandwidth increase serve as reliable indicators of the crack appearance in silicon wafers and are suitable for mechanical quality control and fast wafer inspection

Chrome tannage using high-intensity ultrasonic field.

Science.gov (United States)

Mäntysalo, E; Marjoniemi, M; Kilpeläinen, M

1997-04-01

The process time in chrome tannage in leather making, using an elastic compression cycle followed by irradiation by high-intensity ultrasound, is quite short lasting only a few minutes, compared with a process time of several hours in modern chrome tannage. After ultrasonic irradiation, samples were basified in 17 h in chrome liquor at a pH of 4.0 and the shrinkage temperature was measured. The determination of the efficiency for the chrome liquor penetrating into the hides can be based on the steepness of the shrinkage temperature-processing time curve. An approximate value of 20 degrees C min(-1) can be evaluated for the initial slope of the curve when elastic compression and high-intensity ultrasonic irradiation is used, and a processing time of 2 min is required in chrome liquor (plus 17 h basification and 24 h storage time) to obtain leather stable to boiling. Usually, hides are kept in chrome liquor for 2 h.

Studies on the preparation of Caro’s acid by ultrasonic enhanced electrochemistry

Science.gov (United States)

Li, Linbo; Yu, Zeli; Hong, Tao; Fang, Zhao; Peng, Jishi; Yang, Zhao

2017-06-01

Ultrasonic cavitation effects can generate hydroxyl radicals and high energy, which is widely applied in the field of oxidation currently. Ultrasound-enhanced electrochemical is used to prepare Caro’s acid, which improves the generate rate of Caro’s acid. In this article, the influences of ultrasonic frequency and ultrasonic power on the electrolysis voltage, electrolyte temperature, electrolyte concentration and the concentration of additive in the process of electrochemical preparation of Caro’s acid was studied. And the optimal production conditions were determined. The research results showed that ultrasonic can significantly improve the production of Caro’s acid and the product can increase by about 20 g/L under the best condition.

New developments in ultrasonic imaging of the chest and other body organs

International Nuclear Information System (INIS)

Campbell, G.W.; Anderson, A.L.

1978-01-01

The ultrasonic imaging system described herein was developed to measure chest-wall thickness and the percentage of fat in the chest and around other body organs. The system uses pulse-echo techniques to transmit and detect sound waves reflected from the interfaces of body organs and adjacent tissue. A computer draws these interfaces on color scans, and a code is used to exponentially average data from several points on each scan to find the average thicknesses of the chest wall and fat layers. These average thicknesses are then used to adjust x-ray calibration factors for plutonium lung counters. The correction factor for three subjects measured for fat content ranging from 12.6 to 22.2% was 18 to 41%. The ultrasonic system also defines the shape and position of the kidneys and liver so we are able to more accurately place detectors on the body during in-vivo radiation measurements. We have also developed a technique for displaying the interfaces from a series of ultrasonic chest scans to produce a topographical map that enables us to better understand the shape and contour of the lung and chest-wall interface

Interpretation of ultrasonic images; Interpretation von Ultraschall-Abbildungen

Energy Technology Data Exchange (ETDEWEB)

Mueller, W; Schmitz, V; Kroening, M [Fraunhofer-Institut fuer Zerstoerungsfreie Pruefverfahren, Saarbruecken (Germany)

1998-11-01

During the evaluation of ultrasonic images, e.g. SAFT-reconstructed B-scan images (SAFT=Synthetic Aperture Focusing Technique) it is often difficult to decide, what is the origin of reconstructed image points: were they caused by defects, specimens geometry or mode-conversions. To facilitate this evaluation a tool based on the comparison of data was developed. Different kinds of data comparison are possible: identification of that RF-signals, which caused the reconstructed image point. This is the comparison of a reconstructed image with the corresponding RF-data. Comparison of two reconstructed images performing a superposition using logical operators. In this case e.g. the reconstruction of an unknown reflector is compared with that of a known one. Comparison of raw-RF-data by simultaneous scanning through two data sets. Here the echoes of an unknown reflector are compared with the echoes of a known one. The necessary datasets of known reflectors may be generated experimentally on reference reflectors or modelled. The aim is the identification of the reflector type, e.g. cracklike or not, the determination of position, size and orientation as well as the identification of accompanying satellite echoes. The interpretation of the SAFT-reconstructed B-scan image is carried out by a complete description of the reflector. In addition to the aim of interpretation the tool described is well suited to educate and train ultrasonic testers. (orig./MM) [Deutsch] Bei der Auswertung von Ultraschall-Abbildungen, z.B. SAFT-rekonstruierten B-Bildern (SAFT=Synthetische Apertur Fokus Technik), ist es oft schwierig zu entscheiden, wo rekonstruierte Bildpunkte herruehren: wurden sie durch Materialfehler, Bauteilgeometrie oder durch Wellenumwandlungen versursacht. Um diese Auswertung zu erleichtern, wurde ein Werkzeug entwickelt, welches auf dem Vergleich von Datensaetzen basiert. Es koennen verschiedene Arten des Datenvergleichs durchgefuehrt werden: Identifikation der HF

Single frequency thermal wave radar: A next-generation dynamic thermography for quantitative non-destructive imaging over wide modulation frequency ranges.

Science.gov (United States)

Melnikov, Alexander; Chen, Liangjie; Ramirez Venegas, Diego; Sivagurunathan, Koneswaran; Sun, Qiming; Mandelis, Andreas; Rodriguez, Ignacio Rojas

2018-04-01

Single-Frequency Thermal Wave Radar Imaging (SF-TWRI) was introduced and used to obtain quantitative thickness images of coatings on an aluminum block and on polyetherketone, and to image blind subsurface holes in a steel block. In SF-TWR, the starting and ending frequencies of a linear frequency modulation sweep are chosen to coincide. Using the highest available camera frame rate, SF-TWRI leads to a higher number of sampled points along the modulation waveform than conventional lock-in thermography imaging because it is not limited by conventional undersampling at high frequencies due to camera frame-rate limitations. This property leads to large reduction in measurement time, better quality of images, and higher signal-noise-ratio across wide frequency ranges. For quantitative thin-coating imaging applications, a two-layer photothermal model with lumped parameters was used to reconstruct the layer thickness from multi-frequency SF-TWR images. SF-TWRI represents a next-generation thermography method with superior features for imaging important classes of thin layers, materials, and components that require high-frequency thermal-wave probing well above today's available infrared camera technology frame rates.

Single frequency thermal wave radar: A next-generation dynamic thermography for quantitative non-destructive imaging over wide modulation frequency ranges

Science.gov (United States)

Melnikov, Alexander; Chen, Liangjie; Ramirez Venegas, Diego; Sivagurunathan, Koneswaran; Sun, Qiming; Mandelis, Andreas; Rodriguez, Ignacio Rojas

2018-04-01

Single-Frequency Thermal Wave Radar Imaging (SF-TWRI) was introduced and used to obtain quantitative thickness images of coatings on an aluminum block and on polyetherketone, and to image blind subsurface holes in a steel block. In SF-TWR, the starting and ending frequencies of a linear frequency modulation sweep are chosen to coincide. Using the highest available camera frame rate, SF-TWRI leads to a higher number of sampled points along the modulation waveform than conventional lock-in thermography imaging because it is not limited by conventional undersampling at high frequencies due to camera frame-rate limitations. This property leads to large reduction in measurement time, better quality of images, and higher signal-noise-ratio across wide frequency ranges. For quantitative thin-coating imaging applications, a two-layer photothermal model with lumped parameters was used to reconstruct the layer thickness from multi-frequency SF-TWR images. SF-TWRI represents a next-generation thermography method with superior features for imaging important classes of thin layers, materials, and components that require high-frequency thermal-wave probing well above today's available infrared camera technology frame rates.

Lower sintering temperature of nanostructured dense ceramics compacted from dry nanopowders using powerful ultrasonic action

OpenAIRE

Khasanov, O.; Reichel, U.; Dvilis, E.; Khasanov, A.

2011-01-01

Nanostructured high dense zirconia ceramics have been sintered from dry nanopowders compacted by uniaxial pressing with simultaneous powerful ultrasonic action (PUA). Powerful ultrasound with frequency of 21 kHz was supplied from ultrasonic generator to the mold, which was the ultrasonic wave-guide. Previously the mold was filled by non-agglomerated zirconia nanopowder having average particle size of 40 nm. Any binders or plasticizers were excluded at nanopowder processing. Compaction pressur...

Ultrasonic signature

International Nuclear Information System (INIS)

Borloo, E.; Crutzen, S.

1974-12-01

The unique and tamperproof identification technique developed at Ispra is based on ultrasonic Non-Destructive-Techniques. Reading fingerprints with ultrasonic requires high reproducibility of standard apparatus and transducers. The present report gives an exhaustive description of the ultrasonic technique developed for identification purposes. Different applications of the method are described

The feasibility of the auto tuning respiratory compensation system with ultrasonic image tracking technique.

Science.gov (United States)

Chuang, Ho-Chiao; Hsu, Hsiao-Yu; Nieh, Shu-Kan; Tien, Der-Chi

2015-01-01

developed auto tumor localization system can be evaluated. The results show that the simulated respiratory signals under different frequencies of 0.5, 0.333, 0.25, 0.2 and 0.167 Hz with phase lead compensators were improved and stabilized. The compensation rate increased to the range of 7.04$∼ $18.82%, and the final compensation rate is about 97%. Therefore the auto tumor localization system combined with the ultrasound image analysis techniques is feasible.In this study, the developed ultrasound image analysis techniques combined into the auto tumor localization system has the following four advantages: (1) It is a non-invasive way (ultrasonic images) to monitor the entire compensating process of the active respiration instead of using a C-arm (invasive) to observe the organs motion. (2) During radiation therapy, the whole treatment process can be continuous, which can save the overall treatment time. (3) It is an independent system, which can be mounted onto any treatment couch. (4) Users can operate this system easily without the need of prior complicated training process.

Experimental investigation by laser ultrasonics for high speed train axle diagnostics.

Science.gov (United States)

Cavuto, A; Martarelli, M; Pandarese, G; Revel, G M; Tomasini, E P

2015-01-01

The present paper demonstrates the applicability of a laser-ultrasonic procedure to improve the performances of train axle ultrasonic inspection. The method exploits an air-coupled ultrasonic probe that detects the ultrasonic waves generated by a high-power pulsed laser. As a result, the measurement chain is completely non-contact, from generation to detection, this making it possible to considerably speed up inspection time and make the set-up more flexible. The main advantage of the technique developed is that it works in thermo-elastic regime and it therefore can be considered as a non-destructive method. The laser-ultrasonic procedure investigated has been applied for the inspection of a real high speed train axle provided by the Italian railway company (Trenitalia), on which typical fatigue defects have been expressly created according to standard specifications. A dedicated test bench has been developed so as to rotate the axle with the angle control and to speed up the inspection of the axle surface. The laser-ultrasonic procedure proposed can be automated and is potentially suitable for regular inspection of train axles. The main achievements of the activity described in this paper are: – the study of the effective applicability of laser-ultrasonics for the diagnostic of train hollow axles with variable sections by means of a numerical FE model, – the carrying out of an automated experiment on a real train axle, – the analysis of the sensitivity to experimental parameters, like laser source – receiving probe distance and receiving probe angular position, – the demonstration that the technique is suitable for the detection of surface defects purposely created on the train axle. Copyright © 2014 Elsevier B.V. All rights reserved.

Limited aperture effects on ultrasonic image reconstruction

International Nuclear Information System (INIS)

Kogan, V.G.; Rose, J.H.

1985-01-01

In the inverse Born approximation the shape of a weak scatterer can be determined from a knowledge of the backscattered ultrasonic amplitude for all directions of incidence and all frequencies. Two questions are considered. First, what information on the scatterer shape is preserved and what is degraded if the scattering data are available only within a limited set of incident directions (limited aperture). This problem is addressed for a spherical weakly scattering uniform flaw. It is shown that the problem of a general uniform ellipsoidal flaw can be reduced to the spherical case by a scale transformation; however, the apertures in these two cases must be related by the same transformation. Second, limited aperture and finite bandwidth Born inversions were performed for strongly scattering flaws (voids and cracks) using numerically generated scattering amplitudes. These inversions were then compared with the weak scattering analytic results, which show many common features

Anisotropy analysis of low cement concrete by ultrasonic measurements and image analysis

Directory of Open Access Journals (Sweden)

Martinović Sanja P.

2016-01-01

Full Text Available The analized material was high alumina low cement castable sintered at three different temperatures. Influence of initial material anisotropy on the thermal shock resistance as well as changes of anisotropy level during the thermal shock were studied. Water quench test was used as an experimental method for the thermal stability testing. Surface anisotropy was analysed by image analysis and structural anisotropy using ultrasonic measurements. The results pointed out that the highest homogeinity and the lowest surface and structural anisotropy was for the samples sintered at 1600ºC. Surface anistoropy had prevailing infuence on behavior of material during the thermal shock, but the structural anisotropy should not be neglected. [Projekat Ministarstva nauke Republike Srbije, br. TR 33007

Investigations on Tl-2223 thin films fabricated through ultrasonic ...

Indian Academy of Sciences (India)

Unknown

converted into mist by an ultrasonic nebulizer operating at a frequency of ~ 106 Hz. This mist ... TBCCO system is formed at ~ 890°C, we have used this as the thalliation .... nucleation and growth kinetics induced by highly mobile. Ag particles.

Ultrasonic Fingerprint Sensor With Transmit Beamforming Based on a PMUT Array Bonded to CMOS Circuitry.

Science.gov (United States)

Jiang, Xiaoyue; Tang, Hao-Yen; Lu, Yipeng; Ng, Eldwin J; Tsai, Julius M; Boser, Bernhard E; Horsley, David A

2017-09-01

In this paper, we present a single-chip 65 ×42 element ultrasonic pulse-echo fingerprint sensor with transmit (TX) beamforming based on piezoelectric micromachined ultrasonic transducers directly bonded to a CMOS readout application-specific integrated circuit (ASIC). The readout ASIC was realized in a standard 180-nm CMOS process with a 24-V high-voltage transistor option. Pulse-echo measurements are performed column-by-column in sequence using either one column or five columns to TX the ultrasonic pulse at 20 MHz. TX beamforming is used to focus the ultrasonic beam at the imaging plane where the finger is located, increasing the ultrasonic pressure and narrowing the 3-dB beamwidth to [Formula: see text], a factor of 6.4 narrower than nonbeamformed measurements. The surface of the sensor is coated with a poly-dimethylsiloxane (PDMS) layer to provide good acoustic impedance matching to skin. Scanning laser Doppler vibrometry of the PDMS surface was used to map the ultrasonic pressure field at the imaging surface, demonstrating the expected increase in pressure, and reduction in beamwidth. Imaging experiments were conducted using both PDMS phantoms and real fingerprints. The average image contrast is increased by a factor of 1.5 when beamforming is used.

Analysis of Ultrasonic Resonance Signal in Multi-Layered Structure

International Nuclear Information System (INIS)

Kim, Jae Hoon; Kim, Dong Ryun

2012-01-01

Ultrasonic testing are far superior to other nondestructive tests for detecting the disbond interface which occurred in adhesive interface. However, a solid rocket motor consisting of a steel case, rubber insulation, liner, and propellant poses many difficulties for analyzing ultrasonic waves because of the superposition of reflected waves and large differences in acoustic impedance of various materials. Therefore, ultrasonic tests for detecting the disbond interface in solid rocket motor have been applied in very limited areas between the steel case and rubber insulation using an automatic C-scan system. The existing ultrasonic test cannot detect the disbond interface between the liner and propellant of a solid rocket motor because most of the ultrasonic waves are absorbed in the rubber material which has low acoustic impedance. This problem could be overcome by analyzing the resonance frequency from the frequency spectrum using the ultrasonic resonance method. In this paper, a new technique to detect the disbond interface between the liner and propellant using ultrasonic resonance characteristics is discussed in detail.

Analysis of Ultrasonic Resonance Signal in Multi-Layered Structure

Energy Technology Data Exchange (ETDEWEB)

Kim, Jae Hoon [Dept. of Mechanical Design Engineering, Chungnam National University, Daejeon (Korea, Republic of); Kim, Dong Ryun [Agency for Defense Development, Daejeon (Korea, Republic of)

2012-08-15

Ultrasonic testing are far superior to other nondestructive tests for detecting the disbond interface which occurred in adhesive interface. However, a solid rocket motor consisting of a steel case, rubber insulation, liner, and propellant poses many difficulties for analyzing ultrasonic waves because of the superposition of reflected waves and large differences in acoustic impedance of various materials. Therefore, ultrasonic tests for detecting the disbond interface in solid rocket motor have been applied in very limited areas between the steel case and rubber insulation using an automatic C-scan system. The existing ultrasonic test cannot detect the disbond interface between the liner and propellant of a solid rocket motor because most of the ultrasonic waves are absorbed in the rubber material which has low acoustic impedance. This problem could be overcome by analyzing the resonance frequency from the frequency spectrum using the ultrasonic resonance method. In this paper, a new technique to detect the disbond interface between the liner and propellant using ultrasonic resonance characteristics is discussed in detail.

US images encoding envelope amplitude following narrow band filtering

International Nuclear Information System (INIS)

Sommer, F.G.; Stern, R.A.; Chen, H.S.

1986-01-01

Ultrasonic waveform data from phantoms having differing scattering characteristics and from normal and cirrhotic human liver in vivo were recorded within a standardized dynamic range and filtered with narrow band filters either above or below the mean recorded ultrasonic center frequency. Images created by mapping the amplitudes of received ultrasound following such filtration permitted dramatic differentiation, not discernible in conventional US images, of phantoms having differing scattering characteristics, and of normal and cirrhotic human livers

High temperature flexible ultrasonic transducers for structural health monitoring and NDT

Energy Technology Data Exchange (ETDEWEB)

Shih, J.L. [McGill Univ., Montreal, PQ (Canada). Dept. of Electrical and Computer Engineering; Kobayashi, M.; Jen, C.K.; Tatibouet, J. [National Research Council of Canada, Boucherville, PQ (Canada). Industrial Materials Inst.; Mrad, N. [Department of National Defence, Ottawa, ON (Canada). Air Vehicles Research Station

2009-07-01

Ultrasonic techniques are often used for non-destructive testing (NDT) and structural health monitoring (SHM) of pipes in nuclear and fossil fuel power plants, petrochemical plants and other structures as a method to improve safety and extend the service life of the structure. In such applications, ultrasonic transducers (UTs) must be able to operate at high temperature, and must come in contact with structures that have surfaces with different curvatures. As such, flexible UTs (FUTs) are most suitable because they ensure self-alignment to the object's surface. The purpose of this study was to develop FUTs that have high flexibility similar to commercially available polyvinylidene fluoride PVDF FUTs, but which can operate at up to at least 150 degrees C and have a high ultrasonic performance comparable to commercial broadband UTs. The fabrication of the FUT consisted of a sol-gel based sensor fabrication process. The substrate was a 75 {mu}m thick titanium (Ti) membrane, a piezoelectric composite with a thickness larger than 85 {mu}m and a top electrode. The ultrasonic performance of the FUT in terms of signal strength was found to be at least as good as commercially available broadband ultrasonic transducers at room temperature. Onsite gluing and brazing installation techniques which bond the FUTs onto steel pipes for SHM and NDT purposes up to 100 and 150 degrees C were developed, respectively. The best thickness measurement accuracy of FUT at 150 degrees C was estimated to be 26 {mu}m. 18 refs., 2 tabs., 6 figs.

Ultrasonic characterization of microstructure in powder metal alloy

Science.gov (United States)

Tittmann, B. R.; Ahlberg, L. A.; Fertig, K.

1986-01-01

The ultrasonic wave propagation characteristics were measured for IN-100, a powder metallurgy alloy used for aircraft engine components. This material was as a model system for testing the feasibility of characterizing the microstructure of a variety of inhomogeneous media including powder metals, ceramics, castings and components. The data were obtained for a frequency range from about 2 to 20 MHz and were statistically averaged over numerous volume elements of the samples. Micrographical examination provided size and number distributions for grain and pore structure. The results showed that the predominant source for the ultrasonic attenuation and backscatter was a dense (approx. 100/cubic mm) distribution of small micropores (approx. 10 micron radius). Two samples with different micropore densities were studied in detail to test the feasibility of calculating from observed microstructural parameters the frequency dependence of the microstructural backscatter in the regime for which the wavelength is much larger than the size of the individual scattering centers. Excellent agreement was found between predicted and observed values so as to demonstrate the feasibility of solving the forward problem. The results suggest a way towards the nondestructive detection and characterization of anomalous distributions of micropores when conventional ultrasonic imaging is difficult. The findings are potentially significant toward the application of the early detection of porosity during the materials fabrication process and after manufacturing of potential sites for stress induced void coalescence leading to crack initiation and subsequent failure.

A high-frequency sonar for profiling small-scale subaqueous bedforms

Science.gov (United States)

Dingler, J.R.; Boylls, J.C.; Lowe, R.L.

1977-01-01

A high-resolution ultrasonic profiler has been developed which permits both laboratory and field studies of small-scale subaqueous bedforms. The device uses a 2.5-cm diameter piezoelectric ceramic crystal pulsed at a frequency of 4.5 MHz to obtain vertical accuracy and resolution of at least 1 mm. Compared to other small-scale profiling methods, this ultrasonic technique profiles the bottom more accurately and more rapidly without disturbing the bedforms. These characteristics are vital in wave-dominated nearshore zones where oscillatory flow and low visibility for the most part have stymied detailed bedform studies. In the laboratory the transducer is mounted directly to an instrument carriage. For field work the transducer housing is mounted in a 2 m long aluminum frame which is situated and operated by scuba divers. Observations using the device include ripple geometry and migration, the suspension height of sand during sheet flow, and long-term erosion/deposition at a point. ?? 1977.

Overview of the ultrasonic instrumentation research in the MYRRHA project

Energy Technology Data Exchange (ETDEWEB)

Dierckx, M.; Leysen, W.; Van Dyck, D. [Belgian Nuclear Research Center SCK.CEN (Belgium)

2015-07-01

The Belgian Nuclear Research Centre SCK.CEN is in the process of developing MYRRHA, a new generation IV fast flux research reactor to replace the aging BR2. MYRRHA is conceptualized as an accelerator driven system cooled with lead bismuth eutectic mixture (LBE). As LBE is opaque to visual light, ultrasonic measurement techniques are employed as the main technology to provide feedback where needed. This paper we will give an overview of the R and D at SCK.CEN with respect to ultrasonic instrumentation in heavy liquid metals. High temperature ultrasonic transducers are deployed into the reactor to generate and receive the required ultrasonic signals. The ultrasonic waves are generated and sensed by means of a piezo-electric disc at the heart of the transducer. The acoustic properties of commonly used piezo-electric materials match rather well with the acoustic properties of heavy liquid metals, simplifying the design and construction of high bandwidth ultrasonic transducers for use in heavy liquid metals. The ultrasonic transducers will operate in a liquid metal environment, where radiation and high temperature limit the choice of materials for construction. Moreover, the high surface tension of the liquid metal hinders proper wetting of the transducer, required for optimal transmission and reception of the ultrasonic waves. In a first part of the paper, we will discuss the effect of these parameters on the performance of the overall ultrasonic system. In the second part of the paper, past, present and future ultrasonic experiments in LBE will be reviewed. We will show the results of an experiment where a transducer is scanned near the free surface of an LBE pool to render ultrasonic images of objects submerged in the heavy liquid metal. Additionally, the preliminary results of an ongoing experiment that measures the evolution of LBE wetting on different types of metals and various surface conditions will be reported. The evolution of wetting is an important

Automatic detection and classification of breast tumors in ultrasonic images using texture and morphological features.

Science.gov (United States)

Su, Yanni; Wang, Yuanyuan; Jiao, Jing; Guo, Yi

2011-01-01

Due to severe presence of speckle noise, poor image contrast and irregular lesion shape, it is challenging to build a fully automatic detection and classification system for breast ultrasonic images. In this paper, a novel and effective computer-aided method including generation of a region of interest (ROI), segmentation and classification of breast tumor is proposed without any manual intervention. By incorporating local features of texture and position, a ROI is firstly detected using a self-organizing map neural network. Then a modified Normalized Cut approach considering the weighted neighborhood gray values is proposed to partition the ROI into clusters and get the initial boundary. In addition, a regional-fitting active contour model is used to adjust the few inaccurate initial boundaries for the final segmentation. Finally, three textures and five morphologic features are extracted from each breast tumor; whereby a highly efficient Affinity Propagation clustering is used to fulfill the malignancy and benign classification for an existing database without any training process. The proposed system is validated by 132 cases (67 benignancies and 65 malignancies) with its performance compared to traditional methods such as level set segmentation, artificial neural network classifiers, and so forth. Experiment results show that the proposed system, which needs no training procedure or manual interference, performs best in detection and classification of ultrasonic breast tumors, while having the lowest computation complexity.

Experimental study of underwater transmission characteristics of high-frequency 30 MHz polyurea ultrasonic transducer.

Science.gov (United States)

Nakazawa, Marie; Aoyagi, Takahiro; Tabaru, Masaya; Nakamura, Kentaro; Ueha, Sadayuki

2014-02-01

In this paper, we present the transmission characteristics of a polyurea ultrasonic transducer operating in water. In this study, we used a polyurea transducer with fundamental resonance at approximately 30 MHz. Firstly, acoustic pressure radiated from the transducer was measured using a hydrophone, which has a diameter of 0.2 mm. The transmission characteristics such as relative bandwidth, pulse width, and acoustic sensitivity were calculated from the experimental results. The results of the experiment showed a relative bandwidth of 50% and a pulse width of 0.061 μs. The acoustic sensitivity was 0.60 kPa/V with good linearity, where the correlation coefficient R in the fitting calculation was 0.996. A maximum pressure of 13.1 kPa was observed when the transducer was excited at a zero-to-peak voltage of 21 V. Moreover, we experimentally verified the results. The results of the pulse/echo experiment showed that the estimated diameters of the copper wires were 458 and 726 μm, where the differences between the actual and measured values were 15% and 4%, respectively. Acoustic streaming was also observed so that a particle velocity map was estimated by particle image velocimetry (PIV). The sound pressure calculated from the particle velocity obtained by PIV showed good agreement with the acoustic pressure measured using the hydrophone, where the differences between the calculated and measured values were 12-19%. Copyright © 2013 Elsevier B.V. All rights reserved.

Three Dimensional Speckle Imaging Employing a Frequency-Locked Tunable Diode Laser

Energy Technology Data Exchange (ETDEWEB)

Cannon, Bret D.; Bernacki, Bruce E.; Schiffern, John T.; Mendoza, Albert

2015-09-01

We describe a high accuracy frequency stepping method for a tunable diode laser to improve a three dimensional (3D) imaging approach based upon interferometric speckle imaging. The approach, modeled after Takeda, exploits tuning an illumination laser in frequency as speckle interferograms of the object (specklegrams) are acquired at each frequency in a Michelson interferometer. The resulting 3D hypercube of specklegrams encode spatial information in the x-y plane of each image with laser tuning arrayed along its z-axis. We present laboratory data of before and after results showing enhanced 3D imaging resulting from precise laser frequency control.

Combination probe for optically assisted ultrasonic velocity-change imaging aimed at detecting unstable blood vessel plaque

Science.gov (United States)

Tanigawa, Shohei; Mano, Kazune; Wada, Kenji; Matsunaka, Toshiyuki; Horinaka, Hiromichi

2016-04-01

Blood vessel plaque with a large lipid core is at risk of becoming thrombus and is likely to induce acute heart disease. To prevent this, it is necessary to determine not only the plaque's size but also its chemical composition. We, therefore, made the prototype of a combination probe to diagnose carotid artery plaque. It is used to differentiate propagation characteristics between light spectra and ultrasonic images. By propagating light and ultrasound along a common direction, it is possible to effectively warm the diagnosis domain. Moreover, the probe is thought to be compact and be easy to use for diagnosing human carotid artery plaque. We applied the combination probe to a carotid artery phantom with a lipid area and obtained an image of the ultrasonic velocity change in the fatty area.

Method of noncontacting ultrasonic process monitoring

Science.gov (United States)

Garcia, Gabriel V.; Walter, John B.; Telschow, Kenneth L.

1992-01-01

A method of monitoring a material during processing comprising the steps of (a) shining a detection light on the surface of a material; (b) generating ultrasonic waves at the surface of the material to cause a change in frequency of the detection light; (c) detecting a change in the frequency of the detection light at the surface of the material; (d) detecting said ultrasonic waves at the surface point of detection of the material; (e) measuring a change in the time elapsed from generating the ultrasonic waves at the surface of the material and return to the surface point of detection of the material, to determine the transit time; and (f) comparing the transit time to predetermined values to determine properties such as, density and the elastic quality of the material.

Very high temperature ultrasonic thermometer

International Nuclear Information System (INIS)

Jorzik, E.

1983-01-01

An ultrasonic thermometer comprises an electric pulse transducer head, a pulse transmission line, a notched sensor wire attached to and extending along the axis of said transmission line and a sheath enclosing the transmission line and the sensor wire, a portion of the interior face of the sheath being covered by a stuffing material along at least the length of the notched part of the sensor wire, such that contact between the sensor wire and the stuffing material does not substantially give rise to reflection of an ultrasonic pulse at the point of contact. (author)

Stresses in ultrasonically assisted bone cutting

International Nuclear Information System (INIS)

Alam, K; Mitrofanov, A V; Silberschmidt, V V; Baeker, M

2009-01-01

Bone cutting is a frequently used procedure in the orthopaedic surgery. Modern cutting techniques, such as ultrasonic assisted drilling, enable surgeons to perform precision operations in facial and spinal surgeries. Advanced understanding of the mechanics of bone cutting assisted by ultrasonic vibration is required to minimise bone fractures and to optimise the technique performance. The paper presents results of finite element simulations on ultrasonic and conventional bone cutting analysing the effects of ultrasonic vibration on cutting forces and stress distribution. The developed model is used to study the effects of cutting and vibration parameters (e.g. amplitude and frequency) on the stress distributions in the cutting region.

WE-H-206-01: Photoacoustic Tomography: Multiscale Imaging From Organelles to Patients by Ultrasonically Beating the Optical Diffusion Limit

International Nuclear Information System (INIS)

Wang, L.

2016-01-01

Lihong V. Wang: Photoacoustic tomography (PAT), combining non-ionizing optical and ultrasonic waves via the photoacoustic effect, provides in vivo multiscale functional, metabolic, and molecular imaging. Broad applications include imaging of the breast, brain, skin, esophagus, colon, vascular system, and lymphatic system in humans or animals. Light offers rich contrast but does not penetrate biological tissue in straight paths as x-rays do. Consequently, high-resolution pure optical imaging (e.g., confocal microscopy, two-photon microscopy, and optical coherence tomography) is limited to penetration within the optical diffusion limit (∼1 mm in the skin). Ultrasonic imaging, on the contrary, provides fine spatial resolution but suffers from both poor contrast in early-stage tumors and strong speckle artifacts. In PAT, pulsed laser light penetrates tissue and generates a small but rapid temperature rise, which induces emission of ultrasonic waves due to thermoelastic expansion. The ultrasonic waves, orders of magnitude less scattering than optical waves, are then detected to form high-resolution images of optical absorption at depths up to 7 cm, conquering the optical diffusion limit. PAT is the only modality capable of imaging across the length scales of organelles, cells, tissues, and organs (up to whole-body small animals) with consistent contrast. This rapidly growing technology promises to enable multiscale biological research and accelerate translation from microscopic laboratory discoveries to macroscopic clinical practice. PAT may also hold the key to label-free early detection of cancer by in vivo quantification of hypermetabolism, the quintessential hallmark of malignancy. Learning Objectives: To understand the contrast mechanism of PAT To understand the multiscale applications of PAT Benjamin M. W. Tsui: Multi-modality molecular imaging instrumentation and techniques have been major developments in small animal imaging that has contributed significantly

WE-H-206-01: Photoacoustic Tomography: Multiscale Imaging From Organelles to Patients by Ultrasonically Beating the Optical Diffusion Limit

Energy Technology Data Exchange (ETDEWEB)

Wang, L. [Washington University (United States)

2016-06-15

Lihong V. Wang: Photoacoustic tomography (PAT), combining non-ionizing optical and ultrasonic waves via the photoacoustic effect, provides in vivo multiscale functional, metabolic, and molecular imaging. Broad applications include imaging of the breast, brain, skin, esophagus, colon, vascular system, and lymphatic system in humans or animals. Light offers rich contrast but does not penetrate biological tissue in straight paths as x-rays do. Consequently, high-resolution pure optical imaging (e.g., confocal microscopy, two-photon microscopy, and optical coherence tomography) is limited to penetration within the optical diffusion limit (∼1 mm in the skin). Ultrasonic imaging, on the contrary, provides fine spatial resolution but suffers from both poor contrast in early-stage tumors and strong speckle artifacts. In PAT, pulsed laser light penetrates tissue and generates a small but rapid temperature rise, which induces emission of ultrasonic waves due to thermoelastic expansion. The ultrasonic waves, orders of magnitude less scattering than optical waves, are then detected to form high-resolution images of optical absorption at depths up to 7 cm, conquering the optical diffusion limit. PAT is the only modality capable of imaging across the length scales of organelles, cells, tissues, and organs (up to whole-body small animals) with consistent contrast. This rapidly growing technology promises to enable multiscale biological research and accelerate translation from microscopic laboratory discoveries to macroscopic clinical practice. PAT may also hold the key to label-free early detection of cancer by in vivo quantification of hypermetabolism, the quintessential hallmark of malignancy. Learning Objectives: To understand the contrast mechanism of PAT To understand the multiscale applications of PAT Benjamin M. W. Tsui: Multi-modality molecular imaging instrumentation and techniques have been major developments in small animal imaging that has contributed significantly

Detection of Fatigue Damage by Using Frequency Attenuation of a Laser Ultrasonic Longitudinal Wave

International Nuclear Information System (INIS)

Park, Seung-Kyu; Baik, Sung-Hoon; Jung, Hyun-Kyu; Joo, Young-Sang; Cha, Hyung-Ki; Kang, Young-June

2006-01-01

The measurement of fatigue damage in nuclear power plant components is very important to prevent a catastrophic accident and the subsequent severe losses. Specifically, it is preferred to detect at an early stage of the fatigue damage. If the fatigue damage that is in danger of growing into a fracture is accurately detected, an appropriate treatment could be carried out to improve the condition. Although most engineers and designers take precautions against fatigue, some breakdowns of nuclear power plant components still occur due to fatigue damage. It is considered that ultrasound testing technique is the most promising method to detect the fatigue damage in many nondestructive testing methods. Ultrasound testing method has a variety of elastic waves, such as a longitudinal wave, a shear wave, a surface wave and a lamb wave. Also we can use various analysis methods, such as a velocity variation and a signal attenuation. Laser ultrasonic testing has attracted attention as a non-contact testing technique. This system consists of a pulse laser to remotely generate ultrasound and a laser interferometer to remotely measure the surface displacement due to the generated ultrasound. This noncontact testing technique has the following advantages over the conventional piezoelectric transducers. Firstly, the inspection system can be remotely operated for a structure in hostile environments, such as in high radioactivity, high temperatures and narrow spaces. Secondly, we can obtain lots of information from the received ultrasonic waveforms because the laser ultrasonic technique does not require fluid couplant which disturbs the ultrasonic waveforms. Thirdly, laser ultrasound has a wideband spectrum and a high spatial resolution. Therefore, the laser ultrasound provides more accurate information for a testing material and has potential for the detection of fatigue damage in various metals composing a nuclear power plant

Ultrasonic properties of all-printed piezoelectric polymer transducers

Science.gov (United States)

Wagle, Sanat; Decharat, Adit; Bodö, Peter; Melandsø, Frank

2013-12-01

The ability of producing ultrasonic transducers from screen-printing has been explored experimentally, through printing and characterization of a large number of transducers. In an all-printed test design, 124 transducers with four different electrode sizes ranging from 1 to 4.9 mm2, were printed layer-by-layer on a high performance polyethyleneimine polymer. Inks from ferroelectric and conductive polymers were applied to the active part of a transducer, to provide a good acoustical match between the individual layers. Ultrasonic characterizations of the transducers done by two independent methods provided a broad-banded frequency response with a maximum response around 100 MHz.

High resolution ultrasonic densitometer

International Nuclear Information System (INIS)

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

Reliability of measuring pelvic floor elevation with a diagnostic ultrasonic imaging device

OpenAIRE

Ubukata, Hitomi; Maruyama, Hitoshi; Huo, Ming

2015-01-01

[Purpose] The purpose of this study was to investigate the reliability of measuring the amount of pelvic floor elevation during pelvic and abdominal muscle contraction with a diagnostic ultrasonic imaging device. [Subjects] The study group comprised 11 healthy women without urinary incontinence or previous birth experience. [Methods] We measured the displacement elevation of the bladder base during contraction of the abdominal and pelvic floor muscles was measured using a diagnostic ultrasoni...

Computer analysis of gallbladder ultrasonic images towards recognition of pathological lesions

Science.gov (United States)

Ogiela, M. R.; Bodzioch, S.

2011-06-01

This paper presents a new approach to gallbladder ultrasonic image processing and analysis towards automatic detection and interpretation of disease symptoms on processed US images. First, in this paper, there is presented a new heuristic method of filtering gallbladder contours from images. A major stage in this filtration is to segment and section off areas occupied by the said organ. This paper provides for an inventive algorithm for the holistic extraction of gallbladder image contours, based on rank filtration, as well as on the analysis of line profile sections on tested organs. The second part concerns detecting the most important lesion symptoms of the gallbladder. Automating a process of diagnosis always comes down to developing algorithms used to analyze the object of such diagnosis and verify the occurrence of symptoms related to given affection. The methodology of computer analysis of US gallbladder images presented here is clearly utilitarian in nature and after standardising can be used as a technique for supporting the diagnostics of selected gallbladder disorders using the images of this organ.

A capacitive ultrasonic transducer based on parametric resonance

Science.gov (United States)

Surappa, Sushruta; Satir, Sarp; Levent Degertekin, F.

2017-07-01

A capacitive ultrasonic transducer based on a parametric resonator structure is described and experimentally demonstrated. The transducer structure, which we call capacitive parametric ultrasonic transducer (CPUT), uses a parallel plate capacitor with a movable membrane as part of a degenerate parametric series RLC resonator circuit with a resonance frequency of fo. When the capacitor plate is driven with an incident harmonic ultrasonic wave at the pump frequency of 2fo with sufficient amplitude, the RLC circuit becomes unstable and ultrasonic energy can be efficiently converted to an electrical signal at fo frequency in the RLC circuit. An important characteristic of the CPUT is that unlike other electrostatic transducers, it does not require DC bias or permanent charging to be used as a receiver. We describe the operation of the CPUT using an analytical model and numerical simulations, which shows drive amplitude dependent operation regimes including parametric resonance when a certain threshold is exceeded. We verify these predictions by experiments with a micromachined membrane based capacitor structure in immersion where ultrasonic waves incident at 4.28 MHz parametrically drive a signal with significant amplitude in the 2.14 MHz RLC circuit. With its unique features, the CPUT can be particularly advantageous for applications such as wireless power transfer for biomedical implants and acoustic sensing.

Noninvasive Quantitative Imaging of Collagen Microstructure in Three-Dimensional Hydrogels Using High-Frequency Ultrasound.

Science.gov (United States)

Mercado, Karla P; Helguera, María; Hocking, Denise C; Dalecki, Diane

2015-07-01

Collagen I is widely used as a natural component of biomaterials for both tissue engineering and regenerative medicine applications. The physical and biological properties of fibrillar collagens are strongly tied to variations in collagen fiber microstructure. The goal of this study was to develop the use of high-frequency quantitative ultrasound to assess collagen microstructure within three-dimensional (3D) hydrogels noninvasively and nondestructively. The integrated backscatter coefficient (IBC) was employed as a quantitative ultrasound parameter to detect, image, and quantify spatial variations in collagen fiber density and diameter. Collagen fiber microstructure was varied by fabricating hydrogels with different collagen concentrations or polymerization temperatures. IBC values were computed from measurements of the backscattered radio-frequency ultrasound signals collected using a single-element transducer (38-MHz center frequency, 13-47 MHz bandwidth). The IBC increased linearly with increasing collagen concentration and decreasing polymerization temperature. Parametric 3D images of the IBC were generated to visualize and quantify regional variations in collagen microstructure throughout the volume of hydrogels fabricated in standard tissue culture plates. IBC parametric images of corresponding cell-embedded collagen gels showed cell accumulation within regions having elevated collagen IBC values. The capability of this ultrasound technique to noninvasively detect and quantify spatial differences in collagen microstructure offers a valuable tool to monitor the structural properties of collagen scaffolds during fabrication, to detect functional differences in collagen microstructure, and to guide fundamental research on the interactions of cells and collagen matrices.

Simulation of the Two-Phase Liquid – Gas Flow through Ultrasonic Transceivers Application in Ultrasonic Tomography

Directory of Open Access Journals (Sweden)

Zulkarnay Zakaria

2010-01-01

Full Text Available In this paper, ultrasonic transmission mode tomography was used to visualize the two phase liquid/gas flow in a pipe/vessel. The sensing element consists of 8, 16 and 32 units ultrasonic transceivers were used to cover the pipe cross-section at different time. The motivation of this paper is to analyze the optimum numbers of transceivers which can give the best performance in providing better image of the two phase liquid/gas flow. This paper also details the development of the system including the ultrasonic transduction circuits, the electronic measurement circuits, the data acquisition system and the image reconstruction techniques. Ten conditions of liquid-gas flow have been simulated. The system was found capable of visualizing the internal characteristics and provides the concentration profile for the corresponding liquid and gas phases while the 32 transceivers has provided the best image for the ten conditions applied.

A new deconvolution method applied to ultrasonic images

International Nuclear Information System (INIS)

Sallard, J.

1999-01-01

This dissertation presents the development of a new method for restoration of ultrasonic signals. Our goal is to remove the perturbations induced by the ultrasonic probe and to help to characterize the defects due to a strong local discontinuity of the acoustic impedance. The point of view adopted consists in taking into account the physical properties in the signal processing to develop an algorithm which gives good results even on experimental data. The received ultrasonic signal is modeled as a convolution between a function that represents the waveform emitted by the transducer and a function that is abusively called the 'defect impulse response'. It is established that, in numerous cases, the ultrasonic signal can be expressed as a sum of weighted, phase-shifted replicas of a reference signal. Deconvolution is an ill-posed problem. A priori information must be taken into account to solve the problem. The a priori information translates the physical properties of the ultrasonic signals. The defect impulse response is modeled as a Double-Bernoulli-Gaussian sequence. Deconvolution becomes the problem of detection of the optimal Bernoulli sequence and estimation of the associated complex amplitudes. Optimal parameters of the sequence are those which maximize a likelihood function. We develop a new estimation procedure based on an optimization process. An adapted initialization procedure and an iterative algorithm enables to quickly process a huge number of data. Many experimental ultrasonic data that reflect usual control configurations have been processed and the results demonstrate the robustness of the method. Our algorithm enables not only to remove the waveform emitted by the transducer but also to estimate the phase. This parameter is useful for defect characterization. At last the algorithm makes easier data interpretation by concentrating information. So automatic characterization should be possible in the future. (author)

Mathematical modelling of ultrasonic non-destructive evaluation

Directory of Open Access Journals (Sweden)

Larissa Ju Fradkin

2001-01-01

Full Text Available High-frequency asymptotics have been used at our Centre to develop codes for modelling pulse propagation and scattering in the near-field of the ultrasonic transducers used in NDE (Non-Destructive Evaluation, particularly of walls of nuclear reactors. The codes are hundreds of times faster than the direct numerical codes but no less accurate.

Internal properties assessment in agar wood trees using ultrasonic velocity measurement

International Nuclear Information System (INIS)

Mohd Noorul Ikhsan Mohamed; Mohamad Pauzi Ismail; Mat Rasol Awang; Mohd Fajri Osman; Fakhruzi, M.; Hashim, M.M.

2010-01-01

This paper presents the application of ultrasonic velocity in agar wood trees (Aquilaria crassna) with the purpose of evaluating the relationship of the ultrasonic velocity to the variations of internal properties of trees. In this study, three circular cross-sectional discs from the freshly cut tree were selected as samples. First sample with a big hole (decay) in the middle, second sample with internal resinous and the last one is the sample with no defects. The through transmission ultrasonic testing method was carried out using Tico ultrasonic pulse velocity tester which is from Switzerland. Two-dimensional image of internal properties evaluation by an ultrasonic investigation was obtained using Matlab. The results showed that the ultrasonic wave cannot pass through the internal decay or resinous so that the wave went round it and thus ultrasonic wave velocity significantly decreased by increasing the hole or resinous. The difference in color of the image generated by Matlab software based on variation of ultrasonic velocity between the internal decay area and its surrounding area was obvious. Therefore, the properties of internal properties of the three could be detected by ultrasonic line imaging technique. (author)

Ultrasonic pattern recognition study of feedwater nozzle inner radius indication

International Nuclear Information System (INIS)

Yoneyama, H.; Takama, S.; Kishigami, M.; Sasahara, T.; Ando, H.

1983-01-01

A study was made to distinguish defects on feed-water nozzle inner radius from noise echo caused by stainless steel cladding by using ultrasonic pattern recognition method with frequency analysis technique. Experiment has been successfully performed on flat clad plates and nozzle mock-up containing fatigue cracks and the following results which shows the high capability of frequency analysis technique are obtained

Swept-frequency feedback interferometry using terahertz frequency QCLs: a method for imaging and materials analysis.

Science.gov (United States)

Rakić, Aleksandar D; Taimre, Thomas; Bertling, Karl; Lim, Yah Leng; Dean, Paul; Indjin, Dragan; Ikonić, Zoran; Harrison, Paul; Valavanis, Alexander; Khanna, Suraj P; Lachab, Mohammad; Wilson, Stephen J; Linfield, Edmund H; Davies, A Giles

2013-09-23

The terahertz (THz) frequency quantum cascade laser (QCL) is a compact source of high-power radiation with a narrow intrinsic linewidth. As such, THz QCLs are extremely promising sources for applications including high-resolution spectroscopy, heterodyne detection, and coherent imaging. We exploit the remarkable phase-stability of THz QCLs to create a coherent swept-frequency delayed self-homodyning method for both imaging and materials analysis, using laser feedback interferometry. Using our scheme we obtain amplitude-like and phase-like images with minimal signal processing. We determine the physical relationship between the operating parameters of the laser under feedback and the complex refractive index of the target and demonstrate that this coherent detection method enables extraction of complex refractive indices with high accuracy. This establishes an ultimately compact and easy-to-implement THz imaging and materials analysis system, in which the local oscillator, mixer, and detector are all combined into a single laser.

PSpice Modeling of a Sandwich Piezoelectric Ceramic Ultrasonic Transducer in Longitudinal Vibration.

Science.gov (United States)

Wei, Xiaoyuan; Yang, Yuan; Yao, Wenqing; Zhang, Lei

2017-09-30

Sandwiched piezoelectric transducers are widely used, especially in high power applications. For more convenient analysis and design, a PSpice lossy model of sandwiched piezoelectric ultrasonic transducers in longitudinal vibration is proposed by means of the one-dimensional wave and transmission line theories. With the proposed model, the resonance and antiresonance frequencies are obtained, and it is shown that the simulations and measurements have good consistency. For the purpose of further verification the accuracy and application of the PSpice model, a pitch-catch setup and an experimental platform are built. They include two sandwiched piezoelectric ultrasonic transducers and two aluminum cylinders whose lengths are 20 mm and 100 mm respectively. Based on this pitch-catch setup, the impedance and transient analysis are performed. Compared with the measured results, it is shown that the simulated results have good consistency. In addition, the conclusion can be drawn that the optimal excitation frequency for the pitch-catch setup is not necessarily the resonance frequency of ultrasonic transducers, because the resonance frequency is obtained under no load. The proposed PSpice model of the sandwiched piezoelectric transducer is more conveniently applied to combine with other circuits such as driving circuits, filters, amplifiers, and so on.

Nondestructive control of materials by ultrasonic tests

International Nuclear Information System (INIS)

Mercier, Noelle.

1974-01-01

A bibliographic study of nondestructive control methods of solids by ultrasonic tests, and of the ultrasonic emission of a transducer of finite dimension, is first presented. The principle of two of these methods is verified experimentally; they should permit the measurement of various physical parameters of solids, and the detection of local inhomogeneities. The first method calls upon the analysis of the ultrasonic signal (amplitude and phase), after it has crossed a constant thickness of a metallic specimen. This analysis reveals variations of attenuation and of ultrasonic propagation velocity within the specimen. A good spatial resolution is obtained by using 1mm-diameter probes. The second method leads, thanks to a test rig equipped with broad frequency band electrostatic transducers, to the knowledge of the attenuation law of the specimens as a function of frequency (present range: 5 to 15MHz); from this a classification of these specimens as regards their granulometry is deduced [fr

Classification of breast masses by ultrasonic Nakagami imaging: a feasibility study

Science.gov (United States)

Tsui, Po-Hsiang; Yeh, Chih-Kuang; Chang, Chien-Cheng; Liao, Yin-Yin

2008-11-01

Ultrasound is an important clinical tool in noninvasive diagnoses of breast cancer. The Nakagami statistical parameter estimated from the ultrasonic backscattered envelope has been demonstrated to be useful in complementing conventional B-mode scans when classifying breast masses. However, the shadowing effect caused by certain high-attenuation tumors in the B-mode image makes the tumor contour unclear, and thus it is more difficult to choose an appropriate region of interest from which to collect tumor data for estimating the Nakagami parameter. This study explored the feasibility of using the Nakagami parametric image to overcome the shadowing effect for visualizing the properties of breast masses. Experiments were performed on a breast-mimicking phantom and on some typical clinical cases for cysts, fat and tumors (fibroadenoma) (n = 18) in order to explore the performance of the Nakagami image under ideal and practical conditions. The experimental results showed that the Nakagami image pixels (i.e. the local Nakagami parameter) in the cyst, tumor and fat are 0.21 ± 0.01, 0.65 ± 0.05 and 0.98 ± 0.07, respectively, for six independent phantom measurements, and 0.14 ± 0.03, 0.67 ± 0.11 and 0.89 ± 0.08, respectively, for clinical experiments. This suggests that the Nakagami image is able to classify various breast masses (p < 0.005) although the clinical results from tumors of different cases have a larger variance that may be caused by the complexity of real breast tissues. In particular, unlike the B-mode image, the Nakagami image is not subject to significant shadowing effects, making it useful to complement the B-mode image to describe the tumor contour for identifying the tumor-related region when the shadowing effect is stronger or a low system gain is used.

Classification of breast masses by ultrasonic Nakagami imaging: a feasibility study

Energy Technology Data Exchange (ETDEWEB)

Tsui, P-H; Chang, C-C [Division of Mechanics, Research Center for Applied Sciences, Academia Sinica, 128, Section 2, Academia Road, Nankang, Taipei 11529, Taiwan (China); Yeh, C-K; Liao, Y-Y [Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, Hsinchu, Taiwan (China)], E-mail: mechang@gate.sinica.edu.tw, E-mail: ckyeh@mx.nthu.edu.tw

2008-11-07

Ultrasound is an important clinical tool in noninvasive diagnoses of breast cancer. The Nakagami statistical parameter estimated from the ultrasonic backscattered envelope has been demonstrated to be useful in complementing conventional B-mode scans when classifying breast masses. However, the shadowing effect caused by certain high-attenuation tumors in the B-mode image makes the tumor contour unclear, and thus it is more difficult to choose an appropriate region of interest from which to collect tumor data for estimating the Nakagami parameter. This study explored the feasibility of using the Nakagami parametric image to overcome the shadowing effect for visualizing the properties of breast masses. Experiments were performed on a breast-mimicking phantom and on some typical clinical cases for cysts, fat and tumors (fibroadenoma) (n = 18) in order to explore the performance of the Nakagami image under ideal and practical conditions. The experimental results showed that the Nakagami image pixels (i.e. the local Nakagami parameter) in the cyst, tumor and fat are 0.21 {+-} 0.01, 0.65 {+-} 0.05 and 0.98 {+-} 0.07, respectively, for six independent phantom measurements, and 0.14 {+-} 0.03, 0.67 {+-} 0.11 and 0.89 {+-} 0.08, respectively, for clinical experiments. This suggests that the Nakagami image is able to classify various breast masses (p < 0.005) although the clinical results from tumors of different cases have a larger variance that may be caused by the complexity of real breast tissues. In particular, unlike the B-mode image, the Nakagami image is not subject to significant shadowing effects, making it useful to complement the B-mode image to describe the tumor contour for identifying the tumor-related region when the shadowing effect is stronger or a low system gain is used.

Advances in high frequency ultrasound separation of particulates from biomass.

Science.gov (United States)

Juliano, Pablo; Augustin, Mary Ann; Xu, Xin-Qing; Mawson, Raymond; Knoerzer, Kai

2017-03-01

In recent years the use of high frequency ultrasound standing waves (megasonics) for droplet or cell separation from biomass has emerged beyond the microfluidics scale into the litre to industrial scale applications. The principle for this separation technology relies on the differential positioning of individual droplets or particles across an ultrasonic standing wave field within the reactor and subsequent biomass material predisposition for separation via rapid droplet agglomeration or coalescence into larger entities. Large scale transducers have been characterised with sonochemiluminescence and hydrophones to enable better reactor designs. High frequency enhanced separation technology has been demonstrated at industrial scale for oil recovery in the palm oil industry and at litre scale to assist olive oil, coconut oil and milk fat separation. Other applications include algal cell dewatering and milk fat globule fractionation. Frequency selection depends on the material properties and structure in the biomass mixture. Higher frequencies (1 and 2MHz) have proven preferable for better separation of materials with smaller sized droplets such as milk fat globules. For palm oil and olive oil, separation has been demonstrated within the 400-600kHz region, which has high radical production, without detectable impact on product quality. Crown Copyright © 2016. Published by Elsevier B.V. All rights reserved.

Ultrasound breast imaging using frequency domain reverse time migration

Science.gov (United States)

Roy, O.; Zuberi, M. A. H.; Pratt, R. G.; Duric, N.

2016-04-01

Conventional ultrasonography reconstruction techniques, such as B-mode, are based on a simple wave propagation model derived from a high frequency approximation. Therefore, to minimize model mismatch, the central frequency of the input pulse is typically chosen between 3 and 15 megahertz. Despite the increase in theoretical resolution, operating at higher frequencies comes at the cost of lower signal-to-noise ratio. This ultimately degrades the image contrast and overall quality at higher imaging depths. To address this issue, we investigate a reflection imaging technique, known as reverse time migration, which uses a more accurate propagation model for reconstruction. We present preliminary simulation results as well as physical phantom image reconstructions obtained using data acquired with a breast imaging ultrasound tomography prototype. The original reconstructions are filtered to remove low-wavenumber artifacts that arise due to the inclusion of the direct arrivals. We demonstrate the advantage of using an accurate sound speed model in the reverse time migration process. We also explain how the increase in computational complexity can be mitigated using a frequency domain approach and a parallel computing platform.

Photoacoustic imaging and spectroscopy

CERN Document Server

Wang, Lihong

2009-01-01

Photoacoustics promises to revolutionize medical imaging and may well make as dramatic a contribution to modern medicine as the discovery of the x-ray itself once did. Combining electromagnetic and ultrasonic waves synergistically, photoacoustics can provide deep speckle-free imaging with high electromagnetic contrast at high ultrasonic resolution and without any health risk. While photoacoustic imaging is probably the fastest growing biomedical imaging technology, this book is the first comprehensive volume in this emerging field covering both the physics and the remarkable noninvasive applic

Frequency Domain Image Filtering Using CUDA

Directory of Open Access Journals (Sweden)

Muhammad Awais Rajput

2014-10-01

Full Text Available In this paper, we investigate the implementation of image filtering in frequency domain using NVIDIA?s CUDA (Compute Unified Device Architecture. In contrast to signal and image filtering in spatial domain which uses convolution operations and hence is more compute-intensive for filters having larger spatial extent, the frequency domain filtering uses FFT (Fast Fourier Transform which is much faster and significantly reduces the computational complexity of the filtering. We implement the frequency domain filtering on CPU and GPU respectively and analyze the speed-up obtained from the CUDA?s parallel processing paradigm. In order to demonstrate the efficiency of frequency domain filtering on CUDA, we implement three frequency domain filters, i.e., Butterworth, low-pass and Gaussian for processing different sizes of images on CPU and GPU respectively and perform the GPU vs. CPU benchmarks. The results presented in this paper show that the frequency domain filtering with CUDA achieves significant speed-up over the CPU processing in frequency domain with the same level of (output image quality on both the processing architectures

Frequency domain image filtering using cuda

International Nuclear Information System (INIS)

Rajput, M.A.; Khan, U.A.

2014-01-01

In this paper, we investigate the implementation of image filtering in frequency domain using NVIDIA's CUDA (Compute Unified Device Architecture). In contrast to signal and image filtering in spatial domain which uses convolution operations and hence is more compute-intensive for filters having larger spatial extent, the frequency domain filtering uses FFT (Fast Fourier Transform) which is much faster and significantly reduces the computational complexity of the filtering. We implement the frequency domain filtering on CPU and GPU respectively and analyze the speed-up obtained from the CUDA's parallel processing paradigm. In order to demonstrate the efficiency of frequency domain filtering on CUDA, we implement three frequency domain filters, i.e., Butter worth, low-pass and Gaussian for processing different sizes of images on CPU and GPU respectively and perform the GPU vs. CPU benchmarks. The results presented in this paper show that the frequency domain filtering with CUDA achieves significant speed-up over the CPU processing in frequency domain with the same level of (output) image quality on both the processing architectures. (author)

Dental hard tissue characterization using laser-based ultrasonics

Science.gov (United States)

Blodgett, David W.; Massey, Ward L.

2003-07-01

Dental health care and research workers require a means of imaging the structures within teeth in vivo. One critical need is the detection of tooth decay in its early stages. If decay can be detected early enough, the process can be monitored and interventional procedures, such as fluoride washes and controlled diet, can be initiated to help re-mineralize the tooth. Currently employed x-ray imaging is limited in its ability to visualize interfaces and incapable of detecting decay at a stage early enough to avoid invasive cavity preparation followed by a restoration. To this end, non-destructive and non-contact in vitro measurements on extracted human molars using laser-based ultrasonics are presented. Broadband ultrasonic waves are excited in the extracted sections by using a pulsed carbon-dioxide (CO2) laser operating in a region of high optical absorption in the dental hard tissues. Optical interferometric detection of the ultrasonic wave surface displacements in accomplished with a path-stabilized Michelson-type interferometer. Results for bulk and surface in-vitro characterization of caries are presented on extracted molars with pre-existing caries.

Micromachined Ultrasonic Transducers for 3-D Imaging

DEFF Research Database (Denmark)

Christiansen, Thomas Lehrmann

of state-of-the-art 3-D ultrasound systems. The focus is on row-column addressed transducer arrays. This previously sparsely investigated addressing scheme offers a highly reduced number of transducer elements, resulting in reduced transducer manufacturing costs and data processing. To produce...... such transducer arrays, capacitive micromachined ultrasonic transducer (CMUT) technology is chosen for this project. Properties such as high bandwidth and high design flexibility makes this an attractive transducer technology, which is under continuous development in the research community. A theoretical...... treatment of CMUTs is presented, including investigations of the anisotropic plate behaviour and modal radiation patterns of such devices. Several new CMUT fabrication approaches are developed and investigated in terms of oxide quality and surface protrusions, culminating in a simple four-mask process...

Inspection of copper canister for spent nuclear fuel by means of ultrasound. Copper characterization, FSW monitoring with acoustic emission and ultrasonic imaging

International Nuclear Information System (INIS)

Stepinski, Tadeusz

2009-08-01

This report contains the research results concerning advanced ultrasound for the inspection of copper canisters for spent nuclear fuel obtained at Signals and Systems, Uppsala University in 2008. The first part of the report is concerned with aspects related to ultrasonic attenuation of copper material used for canisters. We present results of attenuation measurement performed for a number of samples taken from a real canister; two from the lid and four from different parts of canister wall. Ultrasonic attenuation of the material originating from canister lid is relatively low (less that 50 dB/m) and essentially frequency independent in the frequency range up to 5 MHz. However, for the material originating from the extruded canister part considerable variations of the attenuation are observed, which can reach even 200 dB/m at 3.5 MHz. In the second part of the report we present further development of the concept of the friction stir welding process monitoring by means of multiple sensors formed into a uniform circular array (UCA). After a brief introduction into modeling Lamb waves and UCA we focus on array processing techniques that enable estimating direction of arrival of multimodal Lamb waves. We consider two new techniques, the Capon beamformer and the broadband multiple signal classification technique (MUSIC). We present simulation results illustrating their performance. In the final part we present the phase shift migration algorithm for ultrasonic imaging of layered media using synthetic aperture concept. We start from explaining theory of the phase migration concept, which is followed by the results of experiments performed on copper blocks with drilled holes. We show that the proposed algorithm performs well for immersion inspection of metal objects and yields both improved spatial resolution and suppressed grain noise

Inspection of copper canister for spent nuclear fuel by means of ultrasound. Copper characterization, FSW monitoring with acoustic emission and ultrasonic imaging

Energy Technology Data Exchange (ETDEWEB)

Stepinski, Tadeusz (ed.); Engholm, Marcus; Olofsson, Tomas (Uppsala Univ., Signals and Systems, Dept. of Technical Sciences, Uppsala (Sweden))

2009-08-15

This report contains the research results concerning advanced ultrasound for the inspection of copper canisters for spent nuclear fuel obtained at Signals and Systems, Uppsala University in 2008. The first part of the report is concerned with aspects related to ultrasonic attenuation of copper material used for canisters. We present results of attenuation measurement performed for a number of samples taken from a real canister; two from the lid and four from different parts of canister wall. Ultrasonic attenuation of the material originating from canister lid is relatively low (less that 50 dB/m) and essentially frequency independent in the frequency range up to 5 MHz. However, for the material originating from the extruded canister part considerable variations of the attenuation are observed, which can reach even 200 dB/m at 3.5 MHz. In the second part of the report we present further development of the concept of the friction stir welding process monitoring by means of multiple sensors formed into a uniform circular array (UCA). After a brief introduction into modeling Lamb waves and UCA we focus on array processing techniques that enable estimating direction of arrival of multimodal Lamb waves. We consider two new techniques, the Capon beamformer and the broadband multiple signal classification technique (MUSIC). We present simulation results illustrating their performance. In the final part we present the phase shift migration algorithm for ultrasonic imaging of layered media using synthetic aperture concept. We start from explaining theory of the phase migration concept, which is followed by the results of experiments performed on copper blocks with drilled holes. We show that the proposed algorithm performs well for immersion inspection of metal objects and yields both improved spatial resolution and suppressed grain noise

Multispectral mid-infrared imaging using frequency upconversion

DEFF Research Database (Denmark)

Sanders, Nicolai Højer; Dam, Jeppe Seidelin; Jensen, Ole Bjarlin

2013-01-01

It has recently been shown that it is possible to upconvert infrared images to the near infrared region with high quantum efficiency and low noise by three-wave mixing with a laser field [1]. If the mixing laser is single-frequency, the upconverted image is simply a band-pass filtered version...... parameter, allowing for fast tuning and hence potentially fast image acquisition, paving the way for upconversion based real time multispectral imaging. In the present realization the upconversion module consists of an external cavity tapered diode laser in a Littrow configuration with a computer controlled...

Fundamentals of ultrasonic phased arrays

CERN Document Server

Schmerr, Lester W

2014-01-01

This book describes in detail the physical and mathematical foundations of ultrasonic phased array measurements.?The book uses linear systems theory to develop a comprehensive model of the signals and images that can be formed with phased arrays. Engineers working in the field of ultrasonic nondestructive evaluation (NDE) will find in this approach a wealth of information on how to design, optimize and interpret ultrasonic inspections with phased arrays. The fundamentals and models described in the book will also be of significant interest to other fields, including the medical ultrasound and

Ultrasonic velocity and absorption study of binary mixtures of cyclohexane with acrylonitrile by interferometric method at different frequencies

Science.gov (United States)

Pawar, N. R.; Chimankar, O. P.; Bhandakkar, V. D.; Padole, N. N.

2012-12-01

The ultrasonic velocity (u), absorption (α), density (ρ), and viscosity (η) has been measured at different frequencies (1MHz to 10MHz) in the binary mixtures of cyclohexane with acrylonitriile over the entire range of composition at temperature 303K. Vander Waal's constant (b), adiabatic compressibility (βa), acoustic impedance (Z), molar volume (V), free length (Lf), free volume, internal pressure, intermolecular radius and relative association have been also calculated. A special application for acrylonitrile is in the manufacture of carbon fibers. These are produced by paralysis of oriented poly acrylonitrile fibers and are used to reinforce composites for high-performance applications in the aircraft, defense and aerospace industries. Other applications of acrylonitrile are in the production of fatty amines, ion exchange resins and fatty amine amides used in cosmetics, adhesives, corrosion inhibitors and water-treatment resins. Cyclohexane derivatives can be used for the synthesis of pharmaceuticals, dyes, herbicides, plant growth regulator, plasticizers, rubber chemicals, nylon, cyclamens and other organic compounds. In the view of these extensive applications of acrylonitrile and cyclohexane in the engineering process, textile and pharmaceutical industries present study provides qualitative information regarding the nature and strength of interaction in the liquid mixtures through derive parameters from ultrasonic velocity and absorption measurement.

Novel power MOSFET-based expander for high frequency ultrasound systems.

Science.gov (United States)

Choi, Hojong; Shung, K Kirk

2014-01-01

The function of an expander is to obstruct the noise signal transmitted by the pulser so that it does not pass into the transducer or receive electronics, where it can produce undesirable ring-down in an ultrasound imaging application. The most common type is a diode-based expander, which is essentially a simple diode-pair, is widely used in pulse-echo measurements and imaging applications because of its simple architecture. However, diode-based expanders may degrade the performance of ultrasonic transducers and electronic components on the receiving and transmitting sides of the ultrasound systems, respectively. Since they are non-linear devices, they cause excessive signal attenuation and noise at higher frequencies and voltages. In this paper, a new type of expander that utilizes power MOSFET components, which we call a power MOSFET-based expander, is introduced and evaluated for use in high frequency ultrasound imaging systems. The performance of a power MOSFET-based expander was evaluated relative to a diode-based expander by comparing the noise figure (NF), insertion loss (IL), total harmonic distortion (THD), response time (RT), electrical impedance (EI) and dynamic power consumption (DPC). The results showed that the power MOSFET-based expander provided better NF (0.76 dB), IL (-0.3 dB) and THD (-62.9 dB), and faster RT (82 ns) than did the diode-based expander (NF (2.6 dB), IL (-1.4 dB), THD (-56.0 dB) and RT (119 ns)) at 70 MHz. The -6 dB bandwidth and the peak-to-peak voltage of the echo signal received by the transducer using the power MOSFET-based expander improved by 17.4% and 240% compared to the diode-based expander, respectively. The new power MOSFET-based expander was shown to yield lower NF, IL and THD, faster RT and lower ring down than the diode-based expander at the expense of higher dynamic power consumption. Copyright © 2013 Elsevier B.V. All rights reserved.

Multichannel analysis of surface-waves and integration of downhole acoustic televiewer imaging, ultrasonic Vs and Vp, and vertical seismic profiling in an NEHRP-standard classification, South of Concordia, Kansas, USA

Science.gov (United States)

Raef, Abdelmoneam; Gad, Sabreen; Tucker-Kulesza, Stacey

2015-10-01

Seismic site characteristics, as pertaining to earthquake hazard reduction, are a function of the subsurface elastic moduli and the geologic structures. This study explores how multiscale (surface, downhole, and laboratory) datasets can be utilized to improve "constrained" average Vs30 (shear-wave velocity to a 30-meter depth). We integrate borehole, surface and laboratory measurements for a seismic site classification based on the standards of the National Earthquake Hazard Reduction Program (NEHRP). The seismic shear-wave velocity (Vs30) was derived from a geophysical inversion workflow that utilized multichannel analysis of surface-waves (MASW) and downhole acoustic televiewer imaging (DATI). P-wave and S-wave velocities, based on laboratory measurements of arrival times of ultrasonic-frequency signals, supported the workflow by enabling us to calculate Poisson's ratio, which was incorporated in building an initial model for the geophysical inversion of MASW. Extraction of core samples from two boreholes provided lithology and thickness calibration of the amplitudes of the acoustic televiewer imaging for each layer. The MASW inversion, for calculating Vs sections, was constrained with both ultrasonic laboratory measurements (from first arrivals of Vs and Vp waveforms at simulated in situ overburden stress conditions) and the downhole acoustic televiewer (DATV) amplitude logs. The Vs30 calculations enabled categorizing the studied site as NEHRP-class "C" - very dense soil and soft rock. Unlike shallow fractured carbonates in the studied area, S-wave and P-wave velocities at ultrasonic frequency for the deeper intact shale core-samples from two boreholes were in better agreement with the corresponding velocities from both a zero-offset vertical seismic profiling (VSP) and inversion of Rayleigh-wave velocity dispersion curves.

Ultrasonic thermometry system for measuring very high temperatures in reactor safety experiments

International Nuclear Information System (INIS)

Carlson, G.A.; Sullivan, W.H.; Plein, H.G.; Kerley, T.M.

1979-06-01

Ultrasonic thermometry has many potential applications in reactor safety experiments, where extremely high temperatures and lack of visual access may preclude the use of conventional diagnostics. This report details ultrasonic thermometry requirements for one such experiment, the molten fuel pool experiment. Sensors, transducers, and signal processing electronics are described in detail. Axial heat transfer in the sensors is modelled and found acceptably small. Measurement errors, calculations of their effect, and ways to minimize them are given. A rotating sensor concept is discussed which holds promise of alleviating sticking problems at high temperature. Applications of ultrasonic thermometry to three in-core experiments are described. In them, five 10-mm-length sensor elements were used to measure axial temperatures in a UO 2 or UO 2 -steel system fission-heated to about 2860 0 C

Nonlinear ultrasonic wave modulation for online fatigue crack detection

Science.gov (United States)

Sohn, Hoon; Lim, Hyung Jin; DeSimio, Martin P.; Brown, Kevin; Derriso, Mark

2014-02-01

This study presents a fatigue crack detection technique using nonlinear ultrasonic wave modulation. Ultrasonic waves at two distinctive driving frequencies are generated and corresponding ultrasonic responses are measured using permanently installed lead zirconate titanate (PZT) transducers with a potential for continuous monitoring. Here, the input signal at the lower driving frequency is often referred to as a 'pumping' signal, and the higher frequency input is referred to as a 'probing' signal. The presence of a system nonlinearity, such as a crack formation, can provide a mechanism for nonlinear wave modulation, and create spectral sidebands around the frequency of the probing signal. A signal processing technique combining linear response subtraction (LRS) and synchronous demodulation (SD) is developed specifically to extract the crack-induced spectral sidebands. The proposed crack detection method is successfully applied to identify actual fatigue cracks grown in metallic plate and complex fitting-lug specimens. Finally, the effect of pumping and probing frequencies on the amplitude of the first spectral sideband is investigated using the first sideband spectrogram (FSS) obtained by sweeping both pumping and probing signals over specified frequency ranges.

Actively adjustable step-type ultrasonic horns in longitudinal vibration

Science.gov (United States)

Lin, Shuyu; Guo, Hao; Xu, Jie

2018-04-01

Actively adjustable longitudinal step-type ultrasonic horns are proposed and studied. The horn is composed of a traditional ultrasonic horn and piezoelectric material. In practical applications, this kind of step-type ultrasonic horn is mechanically excited by an ultrasonic transducer and the piezoelectric material is connected to an adjustable electric impedance. In this research, the effects of the electric impedance and of the location of the piezoelectric material on the performance of the horn are studied. It is shown that when the electric resistance is increased, the resonance frequency of the horn is increased; the displacement magnification is increased when the piezoelectric material is located in the large end and decreased when the piezoelectric material is located in the small end of the horn. The displacement magnification for the piezoelectric material in the large end is larger than that for the piezoelectric material in the small end of the horn. Some step-type ultrasonic horns are designed and manufactured; the resonance frequency and the displacement magnification are measured by means of POLYTEC Laser Scanning vibrometer. It is shown that the theoretical resonance frequency and the displacement magnification are in good agreement with the measured results. It is concluded that by means of the insertion of the piezoelectric material in the longitudinal horn, the horn performance can be adjusted by changing the electric impedance and the location of the piezoelectric material in the horn. It is expected that this kind of adjustable ultrasonic horns can be used in traditional and potential ultrasonic technologies where the vibrational performance adjustment is needed.

Flexible metallic ultrasonic transducers for structural health monitoring of pipes at high temperatures.

Science.gov (United States)

Shih, Jeanne-Louise; Kobayashi, Makiko; Jen, Cheng-Kuei

2010-09-01

Piezoelectric films have been deposited by a sol-gel spray technique onto 75-μm-thick titanium and stainless steel (SS) membranes and have been fabricated into flexible ultrasonic transducers (FUTs). FUTs using titanium membranes were glued and those using SS membranes brazed onto steel pipes, procedures that serve as on-site installation techniques for the purpose of offering continuous thickness monitoring capabilities at up to 490 °C. At 150 °C, the thickness measurement accuracy of a pipe with an outer diameter of 26.6 mm and a wall thickness of 2.5 mm was estimated to be 26 μm and the center frequency of the FUT was 10.8 MHz. It is demonstrated that the frequency bandwidth of the FUTs and SNR of signals using glue or brazing materials as high-temperature couplant for FUTs are sufficient to inspect the steel pipes even with a 2.5 mm wall thickness.

The Effect of Electrical Impedance Matching on the Electromechanical Characteristics of Sandwiched Piezoelectric Ultrasonic Transducers

Directory of Open Access Journals (Sweden)

Yuan Yang

2017-12-01

Full Text Available For achieving the power maximum transmission, the electrical impedance matching (EIM for piezoelectric ultrasonic transducers is highly required. In this paper, the effect of EIM networks on the electromechanical characteristics of sandwiched piezoelectric ultrasonic transducers is investigated in time and frequency domains, based on the PSpice model of single sandwiched piezoelectric ultrasonic transducer. The above-mentioned EIM networks include, series capacitance and parallel inductance (I type and series inductance and parallel capacitance (II type. It is shown that when I and II type EIM networks are used, the resonance and anti-resonance frequencies and the received signal tailing are decreased; II type makes the electro-acoustic power ratio and the signal tailing smaller whereas it makes the electro-acoustic gain ratio larger at resonance frequency. In addition, I type makes the effective electromechanical coupling coefficient increase and II type makes it decrease; II type make the power spectral density at resonance frequency more dramatically increased. Specially, the electro-acoustic power ratio has maximum value near anti-resonance frequency, while the electro-acoustic gain ratio has maximum value near resonance frequency. It can be found that the theoretically analyzed results have good consistency with the measured ones.

A study on the inclusion sizing using immersion ultrasonic C-scan imaging

International Nuclear Information System (INIS)

Chen, D; Xiao, H F; Li, M; Xu, J W

2017-01-01

Inclusion sizing, especially for large inclusions greater than 30μm provides important reference for metallurgical process control and fatigue life assessment of steel. Ultrasonic non-destructive testing (NDT) shows great advantages in detecting infrequently occurred large inclusions than eddy current, magnetic particle, microscopic or macroscopic examination procedures. In this paper, the performance of inclusion sizing by immersion ultrasonic C-scan imaging is studied numerically. A two-dimensional model that consists of spherically focused transducer, water couplant and steel with embedded inclusion is established and solved numerically by the finite element method. The signal intensity distributions of inclusion with different sizes are acquired and the effects of inclusion type, shape, orientation on signal intensity distribution are analysed. The results show that the 6dB-drop threshold has the smallest relative error compared with the 12dB-drop threshold and the full-drop threshold, which is better for determining inclusion size larger than 100μm. Experiment is also performed to validate the simulated results. (paper)

A frequency domain radar interferometric imaging (FII) technique based on high-resolution methods

Science.gov (United States)

Luce, H.; Yamamoto, M.; Fukao, S.; Helal, D.; Crochet, M.

2001-01-01

In the present work, we propose a frequency-domain interferometric imaging (FII) technique for a better knowledge of the vertical distribution of the atmospheric scatterers detected by MST radars. This is an extension of the dual frequency-domain interferometry (FDI) technique to multiple frequencies. Its objective is to reduce the ambiguity (resulting from the use of only two adjacent frequencies), inherent with the FDI technique. Different methods, commonly used in antenna array processing, are first described within the context of application to the FII technique. These methods are the Fourier-based imaging, the Capon's and the singular value decomposition method used with the MUSIC algorithm. Some preliminary simulations and tests performed on data collected with the middle and upper atmosphere (MU) radar (Shigaraki, Japan) are also presented. This work is a first step in the developments of the FII technique which seems to be very promising.

A capacitive ultrasonic transducer based on parametric resonance.

Science.gov (United States)

Surappa, Sushruta; Satir, Sarp; Levent Degertekin, F

2017-07-24

A capacitive ultrasonic transducer based on a parametric resonator structure is described and experimentally demonstrated. The transducer structure, which we call capacitive parametric ultrasonic transducer (CPUT), uses a parallel plate capacitor with a movable membrane as part of a degenerate parametric series RLC resonator circuit with a resonance frequency of f o . When the capacitor plate is driven with an incident harmonic ultrasonic wave at the pump frequency of 2f o with sufficient amplitude, the RLC circuit becomes unstable and ultrasonic energy can be efficiently converted to an electrical signal at f o frequency in the RLC circuit. An important characteristic of the CPUT is that unlike other electrostatic transducers, it does not require DC bias or permanent charging to be used as a receiver. We describe the operation of the CPUT using an analytical model and numerical simulations, which shows drive amplitude dependent operation regimes including parametric resonance when a certain threshold is exceeded. We verify these predictions by experiments with a micromachined membrane based capacitor structure in immersion where ultrasonic waves incident at 4.28 MHz parametrically drive a signal with significant amplitude in the 2.14 MHz RLC circuit. With its unique features, the CPUT can be particularly advantageous for applications such as wireless power transfer for biomedical implants and acoustic sensing.

Ultrasonic force microscopy: detection and imaging of ultra-thin molecular domains.

Science.gov (United States)

Dinelli, Franco; Albonetti, Cristiano; Kolosov, Oleg V

2011-03-01

The analysis of the formation of ultra-thin organic films is a very important issue. In fact, it is known that the properties of organic light emitting diodes and field effect transistors are strongly affected by the early growth stages. For instance, in the case of sexithiophene, the presence of domains made of molecules with the backbone parallel to the substrate surface has been indirectly evidenced by photoluminescence spectroscopy and confocal microscopy. On the contrary, conventional scanning force microscopy both in contact and intermittent contact modes have failed to detect such domains. In this paper, we show that Ultrasonic Force Microscopy (UFM), sensitive to nanomechanical properties, allows one to directly identify the structure of sub-monolayer thick films. Sexithiophene flat domains have been imaged for the first time with nanometer scale spatial resolution. A comparison with lateral force and intermittent contact modes has been carried out in order to explain the origins of the UFM contrast and its advantages. In particular, it indicates that UFM is highly suitable for investigations where high sensitivity to material properties, low specimen damage and high spatial resolution are required. Copyright © 2010 Elsevier B.V. All rights reserved.

Degradation evaluation of high temperature pipeline material for power plant using ultrasonic noise analysis

International Nuclear Information System (INIS)

Lee, Sang Guk; Chung, Min Hwa; Cho, Yong Sang; Lee, In Cheol

2001-01-01

Boiler high-temperature pipelines such as main steam pipe, header and steam drum in fossil power plants are degraded by creep and thermal fatigue damage due to severe operating conditions such as high temperature and high pressure for an extended period time. Conventional measurement techniques for measuring creep damage have such disadvantages as complex preparation and measurement procedures, too many control parameters. And also these techniques have low practicality and applied only to component surfaces with good accessibility. In this paper, artificial degradation test and ultrasonic measurement for their degraded specimens were carried out for the purpose of evaluation for creep and thermal fatigue damage. Absolute measuring method of quantitative ultrasonic measurement for material degradation was established, and long term creep/thermal fatigue degradation tests using life prediction formula were carried out. As a result of ultrasonic tests for crept and thermal fatigued specimens, we conformed that the ultrasonic noise linearly increased in proportion to the increase of degradation.

High speed ultrasonic system to measure bubbles velocities in a horizontal two-phase flow

International Nuclear Information System (INIS)

Cunha Filho, Jurandyr S.; Jian Su; Farias, Marcos S.; Faccini, Jose L.H.; Lamy, Carlos A.

2009-01-01

In this work, a non invasive technique consisting of a high speed ultrasonic multitransducer pulse-echo system was developed to characterize gas-liquid two-phase flow parameters that are important in the study of the primary refrigeration circuit of nuclear reactors. The high speed ultrasonic system consists of two transducers (10 MHz/φ 6.35 mm), a generator/multiplexer board, and software that selects and has a data acquisition system of the ultrasonic signals. The resolutions of the system and the pulse time generated from each transducer are, respectively, 10 ns and 1.06 ms. The system initially was used in the local instantaneous measurement of gas-liquid interface in a circular horizontal pipe test section made of a 5 m long stainless steel pipe of 51.2 mm inner diameter, where the elongated bubbles velocity was measured (Taylor bubbles). The results show that the high speed ultrasonic pulse-echo system provides good results for the determination of elongated bubbles velocities. (author)

Dual-frequency magnetic particle imaging of the Brownian particle contribution

Energy Technology Data Exchange (ETDEWEB)

Viereck, Thilo, E-mail: t.viereck@tu-bs.de; Kuhlmann, Christian; Draack, Sebastian; Schilling, Meinhard; Ludwig, Frank

2017-04-01

Magnetic particle imaging (MPI) is an emerging medical imaging modality based on the non-linear response of magnetic nanoparticles to an exciting magnetic field. MPI has been recognized as a fast imaging technique with high spatial resolution in the mm range. For some applications of MPI, especially in the field of functional imaging, the determination of the particle mobility (Brownian rotation) is of great interest, as it enables binding detection in MPI. It also enables quantitative imaging in the presence of Brownian-dominated particles, which is otherwise implausible. Discrimination of different particle responses in MPI is possible via the joint reconstruction approach. In this contribution, we propose a dual-frequency acquisition scheme to enhance sensitivity and contrast in the detection of different particle mobilities compared to a standard single-frequency MPI protocol. The method takes advantage of the fact, that the magnetization response of the tracer is strongly frequency-dependent, i.e. for low excitation frequencies a stronger Brownian contribution is observed.

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