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V.r. Singh - One of the best experts on this subject based on the ideXlab platform.

  • Ultrasonic propagation in breast tissue with ductal carcinoma
    Indian Journal of Pure & Applied Physics, 2002
    Co-Authors: Kirti Gandhi Bhatia, V.r. Singh, M. C. Bansal, Sanjiv Bhatia
    Abstract:

    Ultrasonic parameters of soft tissue tumours are still not known accurately. Breast tissues with diagnosis of ductal carcinoma are studied. A double-probe through-Transmission Technique is used. Ultrasonic velocity in abnormal breast tissue samples is found between 1438 ms - 1 and 1514 ms - 1 and attenuation between 741 dBm - 1 and 892 dBm - 1 . Other parameters like acoustic impedance and dynamic modulus of elasticity are also determined. Data may be used as an index in the identification and characterization of particular type of tumours after proper standardization.

  • Ultrasonic characteristics of Leiomyoma Uteri in vitro
    Ultrasound in Medicine & Biology, 2001
    Co-Authors: Kirti Bhatia, V.r. Singh
    Abstract:

    Abstract Patients suffer with various abnormalities of body tissues. “Leiomyoma Uteri” is a solid tumor of uterus, one of such abnormalities. To treat such tumors, basic physical and biologic investigations are required to be carried out. In the present work, ultrasonic characterization of soft tissues, in this case, uterine tumor in vitro , are studied. A double probe through-Transmission Technique is used for the measurement of these propagation parameters, viz. , velocity and attenuation. Other parameters like acoustic impedance, dynamic modulus of elasticity and compressibility are also determined. The average velocity and attenuation are found to be 1550 ms −1 and 433 dBm −1 , respectively, at 3.5 MHz frequency and room temperature 28°C. The present investigation is useful in tissue differentiation and tissue identification to enable the doctors to give proper treatment. (E-mail: vrs@csnpl.ren.nic.in)

  • Ultrasonic parameters and relationship between compressive strength, microstructure of gall bladder stones
    European Journal of Ultrasound, 2000
    Co-Authors: R. Agarwal, V.r. Singh
    Abstract:

    Patients with symptomatic stones are at a great risk for complications and these complications are a major cause of morbidity. The gall bladder stones may have a complex structure and variable composition. In the present investigation stones have been grouped into three categories namely cholesterol, bilirubinate and mixed, and a correlation between the surface structure, ultrasonic parameters and compressive strength is estimated. A double-probe through-Transmission Technique was used for the ultrasonic parameters study, a universal testing instrument for hardness and a scanning electron microscope (SEM) for microstructure study. Gall bladder stones of mixed type with higher ultrasonic velocity, less attenuation and higher crushing strength were found to be more difficult to break in comparison to other types of stones. SEM of mixed type stones showed rough surface as compared to bilirubinate and cholesterol stones. The results obtained as well as the relationship might be useful in the design of a focussed ultrasonic 0lithotripter.

  • Ultrasonic velocity and attenuation measurement in kidney stones: correlation to constituents and hardness.
    Bio-Medical Materials and Engineering, 1992
    Co-Authors: V.r. Singh, J. B. Dhawan
    Abstract:

    In this investigation, ultrasonic parameters of kidney stones are measured, in vitro, using a double probe ultrasonic-through-Transmission Technique. Due to the complex chemical structure of these stones, a lal'ge variation in the values of the ultrasonic parameters is found. A correlation between ultrasonic properties and variation in pathology of the renal calculi is also discussed. A double probe ultrasonic-through-Transmission Technique has had positive results in this investigation. The Technique was standardized and calibrated by using solid reference blocks of perspex and stainless steel. Such blocks are also used for the calibration of ultrasonic flaw detection systems. A pulser-receiver (e.g_. Panametrics Model 5052 PR) was used to excite the transmitting and receiving transducers. Two transducers, one for sending ultrasonic pulses to the kidney stone sample being tested, and another for receiving the signal, were used in the study. The output of the receiving transducer was amplified and fed to the Y-axis' of a storage type dual trace cathode ray oscilloscope (Model 05768-S EeIL) , while the X-axis of eRO gave calibrated time scale. The block diagram of experimental setup is shown in Fig_ 1. Ultrasound medical gel was used for proper acoustic coupling between the trans­ ducer and the kidney stone samples. The kidney stone samples were proCured from local

  • A comparative study of fracture strength, ultrasonic properties and chemical constituents of kidney stones.
    Ultrasonics, 1991
    Co-Authors: Ravinder Agarwal, V.r. Singh
    Abstract:

    Ultrasonic properties of kidney stones were studied with a double-probe-through-Transmission Technique, the micro hardness was studied using the Viker indentation method and the chemical composition studied using an X-ray Technique. The microhardness is found to vary with chemical composition as well as ultrasonic propagation velocity. The comparative results obtained are discussed in detail.

Lin Yang - One of the best experts on this subject based on the ideXlab platform.

  • an ultrasonic longitudinal through transmission method to measure the compressive internal stress in epoxy composite specimens of gas insulated metal enclosed switchgear
    Energies, 2020
    Co-Authors: Zhouyiao Zou, Yanpeng Hao, Fangyuan Tian, Yao Zheng, Lin Yang
    Abstract:

    Situations of internal stress in basin insulators inside gas-insulated metal-enclosed switchgear (GIS) can lead to cracks, which can influence the safety and stability of apparatus. However, there is currently no research on internal stress measurements for composites of GIS basin insulators, and only measurements for surface stress. In this paper, an internal stress measurement method for GIS epoxy composite is proposed using an ultrasonic longitudinal through-Transmission Technique based on the acoustoelastic effect. An internal stress measurement system is developed to investigate the relationship between the uniaxial compressive internal stress and the velocity of the ultrasonic wave vertical to the stress in epoxy composite within a range of 0–70 MPa, and to calculate the acoustoelastic coefficient of epoxy composite. The effects of system delay are eliminated in measuring the propagation time. Some epoxy composite cuboid specimens with similar materials and using a manufacturing process similar to those of 252 kV GIS basin insulators are synthesized, and the uniformity of the internal stress in cuboid specimens is verified by finite element simulation. The results reveal a linear increase of the ultrasonic longitudinal wave velocity with increasing stress. It has been shown that the average acoustoelastic coefficient of GIS epoxy composites, using the longitudinal waves vertical to the stress, is 4.556 × 10 −5 /MPa. Additionally, the absolute errors of the internal stress measurements are less than 12.397 MPa. This research shows that the ultrasonic method based on the acoustoelastic effect for measuring the internal stress in GIS epoxy composites is feasible.

James H. Williams - One of the best experts on this subject based on the ideXlab platform.

  • Ultrasonic verification of five wave fronts in unidirectional graphite epoxy composite
    1990
    Co-Authors: Han-song Seng, James H. Williams
    Abstract:

    The existence of five different waves fronts in a unidirectional graphite fiber reinforced epoxy composite with energy flux propagation at the angle of 60 deg with respect to the fiber direction is verified by measuring their corresponding group and phase velocities of longitudinal and shear waves using the through transmission Technique. The experimental and theoretical values of phase velocities show excellent agreement for all three modes of wave propagation. It is also verified that the maximum output voltage amplitude is obtained when the line joining the centers of the transmitting and receiving transducers is parallel to the energy propagation direction defined by the deviation angle.

  • Ultrasonic verification of five wave fronts in unidirectional graphite epoxy composite. Final Report
    1990
    Co-Authors: Han-song Seng, James H. Williams
    Abstract:

    The existence of five different waves fronts in a unidirectional graphite fiber reinforced epoxy composite with energy flux propagation at the angle of 60 deg with respect to the fiber direction is verified by measuring their corresponding group and phase velocities of longitudinal and shear waves using the through transmission Technique. The experimental and theoretical values of phase velocities show excellent agreement for all three modes of wave propagation. It is also verified that the maximum output voltage amplitude is obtained when the line joining the centers of the transmitting and receiving transducers is parallel to the energy propagation direction defined by the deviation angle.

W. Wang - One of the best experts on this subject based on the ideXlab platform.

  • double through transmission bulk wave method for ultrasonic phase velocity measurement and determination of elastic constants of composite materials
    Journal of the Acoustical Society of America, 1992
    Co-Authors: S. I. Rokhlin, W. Wang
    Abstract:

    This paper describes a modification of a nondestructive ultrasonic method for measurements of the phase velocity of bulk waves in arbitrary directions in generally anisotropic materials. In the conventional method the through‐transmission Technique is used for velocity measurements at a specified angle of incidence. When this angle is changed by rotation of the sample, the transmitted beam changes position, and so the position of the receiving transducer must be changed. This leads to experimental difficulties and loss of precision. In the double‐transmission Technique, the ultrasonic wave is reflected from reflector plates behind the sample and returns via the same path to the same position on the transmitter/receiver working in pulse‐echo mode, which eliminates the necessity of readjusting the receiver position. It is also shown that for arbitrary direction of measurement in anisotropic materials, time‐delay measurements give phase velocity regardless of the angle of deviation between phase and group ve...

  • Double through‐transmission bulk wave method for ultrasonic phase velocity measurement and determination of elastic constants of composite materials
    The Journal of the Acoustical Society of America, 1992
    Co-Authors: S. I. Rokhlin, W. Wang
    Abstract:

    This paper describes a modification of a nondestructive ultrasonic method for measurements of the phase velocity of bulk waves in arbitrary directions in generally anisotropic materials. In the conventional method the through‐transmission Technique is used for velocity measurements at a specified angle of incidence. When this angle is changed by rotation of the sample, the transmitted beam changes position, and so the position of the receiving transducer must be changed. This leads to experimental difficulties and loss of precision. In the double‐transmission Technique, the ultrasonic wave is reflected from reflector plates behind the sample and returns via the same path to the same position on the transmitter/receiver working in pulse‐echo mode, which eliminates the necessity of readjusting the receiver position. It is also shown that for arbitrary direction of measurement in anisotropic materials, time‐delay measurements give phase velocity regardless of the angle of deviation between phase and group ve...

S. I. Rokhlin - One of the best experts on this subject based on the ideXlab platform.

  • Ultrasonic waves in layered anisotropic media: characterization of multidirectional composites
    International Journal of Solids and Structures, 2002
    Co-Authors: S. I. Rokhlin, L. Wang
    Abstract:

    Abstract An efficient and stable recursive compliance/stiffness matrix algorithm is presented to model wave propagation in multidirectional composites. The models are applied to clarify angle beam transmission through a multidirectional composite and to process ultrasonic data for determination of the elastic properties of a composite lamina (single ply) from measurements on a multidirectional composite. Ultrasonic characterization of composites using double-through-Transmission and time-resolved line focus acoustic microscopy has been addressed. The double-through-Transmission measurements and simulations show that the transmission amplitude is highly dependent on ply orientation and angle of incidence. The transmission amplitude decreases rapidly with incident angle deviation from the normal; however, a transmission window is found in the incident angle range 45–60° at frequencies below 2.25 MHz. The time-delay measurements by the double-through-Transmission Technique have been used to reconstruct lamina properties using the Floquet wave concept. A unidirectional lamina elastic properties measurement using line focus acoustic microscopy of a multidirectional composite sample is also briefly discussed. The effective elastic properties for the composites are determined from the lamina properties by a Floquet wave dynamic homogenization method.

  • double through transmission bulk wave method for ultrasonic phase velocity measurement and determination of elastic constants of composite materials
    Journal of the Acoustical Society of America, 1992
    Co-Authors: S. I. Rokhlin, W. Wang
    Abstract:

    This paper describes a modification of a nondestructive ultrasonic method for measurements of the phase velocity of bulk waves in arbitrary directions in generally anisotropic materials. In the conventional method the through‐transmission Technique is used for velocity measurements at a specified angle of incidence. When this angle is changed by rotation of the sample, the transmitted beam changes position, and so the position of the receiving transducer must be changed. This leads to experimental difficulties and loss of precision. In the double‐transmission Technique, the ultrasonic wave is reflected from reflector plates behind the sample and returns via the same path to the same position on the transmitter/receiver working in pulse‐echo mode, which eliminates the necessity of readjusting the receiver position. It is also shown that for arbitrary direction of measurement in anisotropic materials, time‐delay measurements give phase velocity regardless of the angle of deviation between phase and group ve...

  • Double through‐transmission bulk wave method for ultrasonic phase velocity measurement and determination of elastic constants of composite materials
    The Journal of the Acoustical Society of America, 1992
    Co-Authors: S. I. Rokhlin, W. Wang
    Abstract:

    This paper describes a modification of a nondestructive ultrasonic method for measurements of the phase velocity of bulk waves in arbitrary directions in generally anisotropic materials. In the conventional method the through‐transmission Technique is used for velocity measurements at a specified angle of incidence. When this angle is changed by rotation of the sample, the transmitted beam changes position, and so the position of the receiving transducer must be changed. This leads to experimental difficulties and loss of precision. In the double‐transmission Technique, the ultrasonic wave is reflected from reflector plates behind the sample and returns via the same path to the same position on the transmitter/receiver working in pulse‐echo mode, which eliminates the necessity of readjusting the receiver position. It is also shown that for arbitrary direction of measurement in anisotropic materials, time‐delay measurements give phase velocity regardless of the angle of deviation between phase and group ve...