• Title, Summary, Keyword: ultrasound characterization

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Nondestructive Characterization and In-situ Monitoring of Corrosion Degradation by Backward Radiated Ultrasound

  • Song, Sung-Jin;Kim, Young H.;Bae, Dong-Ho;Kwon, Sung D.
    • Corrosion Science and Technology
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    • v.4 no.3
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    • pp.114-119
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    • 2005
  • Since the degradation caused by corrosion is restricted to the surface of materials, conventional ultrasonic nondestructive evaluation methods based on ultrasonic bulk waves are not applicable to characterization of the corrosion degradation. To take care of this difficulty, a new nondestructive evaluation method that uses ultrasonic backward radiation has been proposed recently. This paper explores the potential of this newly developed method for nondestructive characterization and in-situ monitoring of corrosion degradation. Specifically, backward radiated ultrasounds from aged thermo-mechanically controlled process (TMCP) steel specimens by corrosion fatigue were measured and their characteristics were correlated to those of the aged specimens. The excellent correlation observed in the present study demonstrates the high potential of the backward radiated ultrasound as an effective tool for nondestructive characterization of corrosion degradation. In addition, the potential of the backward radiated ultrasound to in-situ monitoring of corrosion degradation is under current investigation.

Role of Ultrasound in Characterization of Ovarian Masses

  • Hafeez, Saima;Sufian, Saira;Beg, Madiha;Hadi, Quratulain;Jamil, Yasir;Masroor, Imrana
    • Asian Pacific Journal of Cancer Prevention
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    • v.14 no.1
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    • pp.603-606
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    • 2013
  • Background: Ovarian cancer is the second most common malignancy in Pakistani women, accounting for 4% of all cancers in the female population. The aim of this study was to determine sensitivity, specificity, positive and negative predictive values and 95% confidence intervals for ultrasound in characterization of ovarian masses in patients presenting at public and private tertiary care hospitals in Karachi, Pakistan. Materials and Methods: We adopted a cross-sectional analytical study design to retrospectively collect data from January 2009-11 from medical records of two tertiary care hospitals. Using a non-probability purposive sampling technique, we recruited a sample of 86 women aged between 15 and 85 years fulfilling inclusion criteria with histopathologically proven ovarian masses presenting for an ultrasound examination in our radiology departments. Results: Our retrospective data depicted sensitivity and specificity of ultrasound to be 90.7%, 95%CI (0.77, 0.97) and 91.4%, 95%CI (0.76, 0.98) respectively. Positive predictive value was 93%, 95%CI (0.79, 0.98) and negative predictive value was 89%, 95%CI (0.73, 0.96). A total of 78 ovarian masses were detected, out of which 42 were malignant and 36 were benign. Conclusions: Results of our study further reinforce the conclusion that ultrasound should be used as an initial modality of choice in the workup of every woman suspected of having an ovarian mass. It not only results in decreasing the mortality but also avoids unnecessary surgical interventions.

Development of Flexible Ultrasound System for Elastography (탄성 영상법 개발을 위한 유연성 높은 초음파 시스템의 구현)

  • Kim, D.I.;Lee, S.Y.;Cho, M.H.
    • Journal of Biomedical Engineering Research
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    • v.33 no.1
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    • pp.32-38
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    • 2012
  • Recently, several ultrasound imaging techniques for tissue characterization have been developed. Among them, ultrasound elastography is regarded as the most promising modality and has been rapidly developed. One of ultrasound elastography techniques is shear modulus imaging. Normal and cancerous tissues show big difference of shear moduli and they have good image contrast. However shear wave elastography requires more complicated hardware and more computations for image reconstruction algorithm. Therefore new efficient techniques are being developed. In this paper, we have developed a very flexible ultrasound system for elastography experiments. The developed system has capabilities to acquire ultrasound RF data of all channels and generate arbitrary ultrasound pulse sequences. It has a huge amount of memories for RF data acquisition and a simple and flexible pulse generator. We have verified the performance of the system showing conventional B-mode images and preliminary results of elastography. The developed system will be used to verify our own reconstruction algorithm and to develop more efficient elastography techniques.

Contrast-Enhanced Ultrasound and Shear Wave Elastography Evaluation of Crohn's Disease Activity in Three Adolescent Patients

  • Thimm, Matthew A;Cuffari, Carmen;Garcia, Alejandro;Sidhu, Sarah;Hwang, Misun
    • Pediatric Gastroenterology, Hepatology & Nutrition
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    • v.22 no.3
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    • pp.282-290
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    • 2019
  • Characterizing inflammation and fibrosis in Crohn's disease (CD) is necessary to guide clinical management, but distinguishing the two remains challenging. Novel ultrasound (US) techniques: contrast-enhanced US (CEUS) and shear wave elastography (SWE) offer great potential in evaluating disease activity in pediatric patients. Three patients ages 16 to 20 with known CD underwent CEUS and SWE to characterize bowel wall inflammation and fibrosis. Magnetic resonance enterography, endoscopy, or surgical pathology findings are also described when available. The patients' disease activity included acute inflammation, chronic inflammation with stricture formation, and a fibrotic surgical anastomosis without inflammation. CEUS was useful in determining the degree of inflammation, and SWE identified bowel wall fibrosis. Used together these techniques allow for better characterization of the degree of fibrosis and inflammation in bowel strictures. With further validation CEUS and SWE may allow for improved characterization of bowel strictures and disease flares in pediatric patients suffering from CD.

Parameter Estimation of Tissue Structure Characteristics in Ultrasound Measurement (초음파를 이용한 조직구조 특성변수의 측정)

  • 곽철은;김종원
    • Journal of Biomedical Engineering Research
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    • v.7 no.1
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    • pp.41-44
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    • 1986
  • The objective of tissue characterization is to provide quantitative information about the physical state of tissue interrogated by an ultrasound beam. In the computer simulation, it was found that the echoes were composed of the interferences of the ultrasonic waves reflected from both sides of the thin object, and could be separated by the spectral correlation method. Also, the phantom study demonstrates that thickness of the thin acryl layer beyond the resolution of common ultrasonic imaging systems can be measured- using this method.

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Release of Organic Matter and Behavior of Nitrogen in the Degradation of Sewage Sludge Using Ultrasound (초음파를 이용한 하수 슬러지 분해에서 유기물 방출과 질소 거동)

  • Yoon, Yong-Soo;Kang, Gwang-Nam;Choi, Suk-Soon
    • Journal of the Korea Organic Resources Recycling Association
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    • v.10 no.4
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    • pp.75-80
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    • 2002
  • The sewage sludge with concentrated MLSS, ranging from 5967 to 8400mg/L was degraded by ultrasound. In this study, ultrasound treatment was used to investigate the behavior characterization of SBOD, sludge biodegradation, C/N ratio, TN, turbidity and sludge morphology. From the experimental results of C/N ratio change and TN removal, the optimal irradiation time was found to be 10 minutes. The results showed the relative index of sludge biodegradation(SBOD/TCOD) was enhanced to 0.76 from the initial value of 0.013 at the 5967mg/L MLSS, during the 60minutes treatment. Throughout this research, the results provide useful engineering reference data for reuse of sewage sludge using ultrasound.

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Development of Laser-Based Resonant Ultrasound Spectroscopy(Laser-RUS) System for the Detection of Micro Crack in Materials (재료의 미세결함 검출을 위한 레이저 공명 초음파 분광(Laser-RUS)시스템 개발)

  • Kang, Young-June;Kim, Jin-Soo;Park, Seung-Kyu;Baik, Sung-Hoon;Choi, Nag-Jung
    • Journal of the Korean Society for Precision Engineering
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    • v.27 no.1
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    • pp.41-48
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    • 2010
  • Non-contacting, laser-based resonant ultrasound spectroscopy (L-RUS) was applied to characterize the microstructure of a material. L-RUS is widely used by virtue of its many features. Firstly, L-RUS can be used to measure mechanical damping which related to the microstructural variations (grain boundary, grain size, precipitation, defects, dislocations etc). Secondly, L-RUS technology can be applied to various areas, such as the noncontact and nondestructive quality test for precision components as well as noncontact and nondestructive materials characterization. In addition, L-RUS technology can measure the whole field resonant frequency at once. In this paper, we evaluated material characteristics such as resonant frequency, nonlinear propagation characteristic through the development of Laser-Based Resonant Ultrasound spectroscopy (Laser-RUS) System for the detection of Micro Crack in Materials.

Infrared Thermography Characterization of Defects in Seamless Pipes Using an Infrared Reflector

  • Park, Hee-Sang;Choi, Man-Yong;Park, Jeong-Hak;Lee, Jea-Jung;Kim, Won-Tae;Lee, Bo-Young
    • Journal of the Korean Society for Nondestructive Testing
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    • v.32 no.3
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    • pp.284-290
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    • 2012
  • Infrared thermography uses infrared energy radiated from any objects above absolute zero temperature, and the range of its application has been constantly broadened. As one of the active test techniques detecting radiant energy generated when energy is applied to an object, ultrasound infrared thermography is a method of detecting defects through hot spots occurring at a defect area when 15~100 kHz of ultrasound is excited to an object. This technique is effective in detecting a wide range affected by ultrasound and vibration in real time. Especially, it is really effective when a defect area is minute. Therefore, this study conducted thermography through lock-in signal processing when an actual defect exists inside the austenite STS304 seamless pipe, which simulates thermal fatigue cracks in a nuclear power plant pipe. With ultrasound excited, this study could detect defects on the rear of a pipe by using an aluminium reflector. Besides, by regulating the angle of the aluminium reflector, this study could detect both front and rear defects as a single infrared thermography image.

Characterization of CFRP Laminates′Layups Using Through-Transmitting Ultrasound Waves

  • Im, Kwang-Hee;David K. Hsu;Cho, Young-Tae;Park, Jae-Woung;Sim, Jae-Ki;Yang, In-Young
    • Journal of Mechanical Science and Technology
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    • v.16 no.3
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    • pp.292-301
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    • 2002
  • Ultrasound waves interact strongly with the orientation and sequence of the plies in a layup when propagating in the thickness direction of composite laminates. Also the layup orientation greatly influences its properties in a composite laminate. If the layup orientation of a ply is misaligned, it could result in the part being rejected and discarded. Now, most researchers cut a small coupon from the waste edge and use a microscope to optically verify the ply sequences on important parts. This may add a substantial cost to the production since the test is both labor intensive and performed after the part is cured. A nondestructive technique would be very beneficial, which could be used to test the part after curing and requires less time than the optical test. Therefore we have developed, reduced, and implemented a novel ply-by-ply vector decomposition model for composite laminates fabricated from unidirectional plies. This model decomposes the transmission of a linearly polarized ultrasound wave into orthogonal components through each ply of a laminate. High probability is found, by comparisons between the model and tests, in characterizing cured layups of the laminates by using the proposed method.

NDE Inspecting Techniques for Wind Turbine Blades Using Terahertz Waves (테라헤르츠파를 이용한 풍력터빈 블레이드 NDE 탐상 평가기법)

  • Im, Kwang-Hee;Kim, Sun-Kyu;Jung, Jong-An;Cho, Young-Tae;Woo, Yong-Deuck
    • Journal of Advanced Engineering and Technology
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    • v.11 no.4
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    • pp.245-251
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    • 2018
  • Terahertz waves (T-ray) was extensively studied for the NDE (nondestructive evaluation) of characterization of trailing edges for a use of turbines composed with composite materials. The used NDE system were consisted of both CW(Continuous wave) and TDS (Time domain spectroscopy). The FRP composites were utilized for two kinds of both trailing edges of wind energy (non-conducting polymeric composites) and carbon fiber composites with conducting properties. The signals of T-ray in the TDS (Time domain spectroscopy) mode resembles almost that of ultrasound waves; however, a terahertz pulse could not penetrate a material with conductivity unlike ultrasound. Also, a method was suggested to obtain the "n" in the materials, which is called the refractive index (n). The data of refractive index (n) could be solved for the trailing edges. The trailing edges were scanned for characterization and inspection. C-scan and B-scan images were obtained and best optimal NDE techniques were suggested for complicated geometry samples by terahertz radiation. Especially, it is found that the defect image of T-ray corresponded with defect locations for the trailing edges of wind mill.