• Title/Summary/Keyword: beam attenuation coefficient

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Measurement of Crack Length by Ultrasonic Attenuation Coefficient (초음파 감쇠계수에 의한 균열길이의 측정)

  • Chung, Nam-Yong;Park, Sung-Il
    • Proceedings of the KSME Conference
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    • 2003.04a
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    • pp.340-345
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    • 2003
  • In this paper, the ultrasonic attenuation coefficient was measured by variation of crack length for double-cantilever beam(DCB) specimen. The energy release rate, G, was obtained by the experimental measurement of compliance. The experimental results represents that the relation between crack length for the ultrasonic attenuation coefficient and energy release rate is increased proportionally. From the results of experiments, the measurement method of crack length by the ultrasonic attenuation coefficient was proposed and discussed.

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Measurement of Crack Length by Ultrasonic Attenuation Coefficient (초음파 감쇠계수에 의한 균열길이의 측정)

  • Chung, Nam-Yong;Park, Sung-Il
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.28 no.4
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    • pp.386-393
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    • 2004
  • In this paper, the ultrasonic attenuation coefficient was measured by variation of crack length for double-cantilever beam(DCB) specimen. The energy release rate, G, was obtained by the experimental measurement of compliance. The experimental results represents that the crack length for the ultrasonic attenuation coefficient and energy release rate is increases proportionally From the experimental results, we proposed a detecting method of the crack length by the ultrasonic attenuation coefficient and discussed it.

DETECTION OF INTERFACIAL CRACK LENGTH BY USING ULTRASONIC ATTENUATION COEFFICIENTS ON ADHESIVELY BONDED JOINTS

  • Chung, N.Y.;Park, S.I.
    • International Journal of Automotive Technology
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    • v.5 no.4
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    • pp.303-309
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    • 2004
  • In this paper, an interfacial crack length has been detected by using the ultrasonic attenuation coefficient on the adhesively bonded double-cantilever beam (DCB) joints. The correlations between energy release rates which were investigated by experimental measurement, the boundary element method (BEM) and Ripling's equation are compared with each other. The experimental results show that the interfacial crack length for the ultrasonic attenuation coefficient and energy release rate increases proportionally. From the experimental results, we propose a method to detect the interfacial crack length by using the ultrasonic attenuation coefficient and discuss it.

Measurement of Crack Length by Ultrasonic Attenuation Coefficients on Interfaces of Al/Epoxy Bonded Dissimilar Materials (Al/Epoxy 이종재 접합 계면의 초음파 감쇠계수에 의한 균열길이의 측정)

  • Park, Sung-Il;Chung, Nam-Yong
    • Proceedings of the KSME Conference
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    • 2003.11a
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    • pp.1109-1114
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    • 2003
  • The initial crack often occurs on the bonded interface and it is the general cause of the interface fracture. It is very significant to establish the measurement method of interfacial crack by applying the ultrasonic technology into the interface of bonded dissimilar materials. In this paper, the interfacial crack length was measured by ultrasonic attenuation coefficient in the Al/Epoxy bonded dissimilar materials of double-cantilever beam(DCB). The energy release rate, G, was obtained by the experimental and Ripling's equation measurement of compliance. The experimental results represent that the relation between interfacial crack length for the ultrasonic attenuation coefficient and energy release rate is increased proportionally. From the experimental results, a measurement method of the interfacial crack length by the ultrasonic attenuation coefficient was proposed and discussed.

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A Study on the Correction of Beam Pattern for the Ultrasonic Attenuation Coefficient Estimation (초음파 감쇠계수 주정에 있어서 빔 형태의 보정에 관한 연구)

  • Kim, Gi-Uk;Choe, Heung-Ho;Hong, Seung-Hong
    • Journal of Biomedical Engineering Research
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    • v.8 no.1
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    • pp.41-48
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    • 1987
  • In estimating the freguency-dependent attenuation coefficient, we analyzed the range-dependent ultrasonic beam and proposed the method of calculating the experimental equation of beam pattern in order to reduce the error on the influence of beam pattern. These experimental equations are divided into the spectral centroid and the spec ural standard deviation slope according to axial propagation length. These are repnesented by the first-order equation in the near field of the beam and the second- order eqLlatlon In the far field. In order to prove the validity of this method, the attenuation coefficients of the non-corrected ease and the corrected case are compared. Using the reflected signal from acryle plate, the attenuation coefficients were estimated by the spectral shift method ann the spectral difference method. The result shows attenuation coeffi talents after correction are better than attenuation coefficients before correction. And this method can be applied In vivo measurement.

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Determination of the Effective Energy of X-Ray Beam Using Optically Stimulated Luminescent nanoDot Dosimeters (광자극형광나노닷선량계를 사용한 X선 빔의 유효에너지 결정)

  • Kim, Jongeon;Lee, Sanghun
    • Journal of the Korean Society of Radiology
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    • v.9 no.6
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    • pp.375-379
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    • 2015
  • The purpose of this study is to determine the effective energy of a polyenegetic X-ray beam. The half value layer(HVL) of aluminum for 80 kVp X-ray beam was measured by using optically stimulated luminescent nanoDot dosimeters(OSLnDs). The linear attenuation coefficient(${\mu}$) was calculated using the measured HVL. And the mass attenuation coefficient(${\mu}/{\rho}$) was obtained by dividing the linear attenuation coefficient by the density(${\rho}$) of aluminum. The effective energy($E_{eff}$) of the obtained mass attenuation coefficient was determined using data of the X-ray mass attenuation coefficients for photon energies of aluminum given by National Institute of Standards and Technology(NIST). As a result, the HVL value is 2.262 mmAl. The ${\mu}$ value is $3.06cm^{-1}$. The ${\mu}/{\rho}$ value is $1.114cm^2/g$. And the $E_{eff}$ value was determined at 29.79 keV.

Determination of the Equivalent Energy of a 6 MV X-ray Beam (6 MV X-선 빔의 등가에너지 결정)

  • Kim, Jong-Eon;Park, Byung-Do
    • Journal of the Korean Society of Radiology
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    • v.10 no.8
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    • pp.591-596
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    • 2016
  • The purpose of this study is to determine the equivalent energy of a 6MV X-ray beam in the experiment. The half-value layer (HVL) of lead for the 6 MV X-ray beam was measured using an ionization chamber. The linear attenuation coefficients were calculated with HVL. And, the mass attenuation coefficient was obtained by dividing the linear attenuation coefficient by the density of lead. The equivalent energy of mass attenuation coefficient was determined using the photon energy versus mass attenuation coefficient data of lead given by National Institute of Standards and Technology (NIST). In conclusion, the equivalent energy of the 6 MV X-ray beam was determined to be 1.61 MeV. This equivalent energy was determined to be about 30% lower than reported by Reft. The reason is presumed to be due to the presence of an air cavity between the lead attenuators.

Measurement of Interfacial Crack Length by Ultrasonic Attenuation Coefficients on Adhesively Bonded Components (접착부재의 초음파 감쇠계수에 의한 계면균열 길이의 측정)

  • 정남용;박성일
    • Transactions of the Korean Society of Automotive Engineers
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    • v.12 no.1
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    • pp.130-137
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    • 2004
  • The ultrasonic attenuation coefficients were measured by interfacial crack length in the adhesive components of double-cantilever beam(DCB). The energy release rate, G, was obtained by the experimental measurement of compliance. The numerical analysis by the boundary element method(BEM) and Ripling's equation was investigated. The experimental results represent that the relation between interfacial crack length for the ultrasonic attenuation coefficient and energy release rate is increased proportionally. A measurement method of the interfacial crack length by the ultrasonic attenuation coefficient was proposed and discussed.

Calculation Formula for Effective Photon Energy in kV X-ray Beam of Mammography (유방촬영의 kV X-선 빔에서 유효광자에너지에 대한 계산식)

  • Young-On Park;Sang-Hun Lee;Jong-Eon Kim
    • Journal of the Korean Society of Radiology
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    • v.17 no.4
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    • pp.507-514
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    • 2023
  • The purpose of this study is to find a formula that can easily calculate the effective photon energy in the X-ray beam of mammography. The tube voltage measured for each set tube voltage was obtained using the X2 MAM Sensor. The mass attenuation coefficient for aluminum of the aluminum filter was obtained from the half value layer measurement from each measured tube voltage X-ray beam. The mass attenuation coefficient of aluminum obtained from each measured tube voltage X-ray beam was corresponded to the mass attenuation coefficient of aluminum for each photon energy obtained from NIST. The photon energy corresponding to the matching mass attenuation coefficient was determined as the effective photon energy. The formula for calculating the determined effective photon energy was obtained by polynomial matching of the effective photon energy for each tube voltage in the Origin pro 2019b statistical program as y = 28.98968-1.91738x + 0.07786x2-0.000946717x3. Here, x is the measuring tube voltage and y is the effective photon energy. The calculation formula of the effective photon energy of the mammography X-ray beam obtained in this study is considered to be very useful in obtaining the interaction coefficient between the X-ray beam and a certain substance in clinical practice.

Wear Debris Concentration Measurement by Laser Beam Attenuation (광감쇄를 이용한 마모입자의 농도 측정)

  • 강기호;손정영;전형욱;윤의성;안효석
    • Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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    • 1990.11a
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    • pp.58-62
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    • 1990
  • The size and concentration of wear debris in lubricating oil often reveal the operating condition of the rotating machinery. To evaluate the possible application of light attenuation measurement for the estimation of wear debris concentration in the lubricating oil, the light transmittance through the lubricating oil cell contaminated with various concentrations of diatomite particles was measured, the attenuation coefficient was estimated from the transmittance measurement and the coefficients were compared with those obtained from the scattering theory. The comparision showed good agreements between them. It is also noted that the experimentally determined attenuation coefficient showed almost linear relation with particle weight concentrations for the concentrations within the range of 2000 ppm. For the case of 0 ppm weight concentration of diatomite particles in the lubricating oil cell, the thickness of the cell required to give $100 \mu W$ light attenuation is 7.75 mm. This result indicates that the light attenuation method will be one of the possible candidates of machine failure diagnostic sensors for the estimation of wear debris concentration in the lubricating oil.

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