• Title/Summary/Keyword: IC values

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J_{Ic}$ evaluation of smooth and side-grooved CT specimens in submerged arc-welded SB 41 (SB41강 潛弧熔接部의 平滑 및 側面을 CT試驗片의 J_{Ic}$ 評價)

  • 오세욱;안광주;이태종
    • Journal of Welding and Joining
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    • v.4 no.1
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    • pp.47-57
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    • 1986
  • The elastic-plastic fracture toughness J_{Ic}$ of submerged arc welded structural steel $SB_{41}$ which has the properties of low strength and high ductility was discussed, especially paying attention to a comparison between two methods recommended by ASTM and JSME. $J_{IC}$ tests were carried out with compact specimens by means of R-curve, SZW, ultrasonic and electric potential methods. Based on the investigations in this study, the results obtained are as follows; (1) The JSME R-curve method gave the smallest $J_{IC}$ values which were physically closest to the crack initiation and seemed to be more practical and stable procedure between the two R-curve methods. (2) The JSME SZW method tended to slightly overestimate the $J_{IC}$ values at initiation of ductile tearing. (3) The ultrasonic and electric potential methods which also had a tendency to overestimate these $J_{IC}$ values were confirmed to be applicable and useful in determining these values. (4) The $J_{IC}$ values by the JSME R-curve method were 18.06 kgf/mm and 17.25kgf/ mm for the smooths and the side grooved CT specimen respectively.

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A novel semi-empirical technique for improving API X70 pipeline steel fracture toughness test data

  • Mohammad Reza Movahedi;Sayyed Hojjat Hashemi
    • Steel and Composite Structures
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    • v.51 no.4
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    • pp.351-361
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    • 2024
  • Accurate measurement of KIC values for gas pipeline steels is important for assessing pipe safety using failure assessment diagrams. As direct measurement of KIC was impossible for the API X70 pipeline steel, multi-specimen fracture tests were conducted to measure JIC using three-point bend geometry. The J values were calculated from load-displacement (F-δ) plots, and the associated crack extensions were measured from the fracture surface of test specimens. Valid data points were found for the constructed J-Δa plot resulting in JIC=356kN/m. More data points were added analytically to the J-Δa plot to increase the number of data points without performing additional experiments for different J-Δa zones where test data was unavailable. Consequently, displacement (δ) and crack-growth (Δa) from multi-specimen tests (with small displacements) were used simultaneously, resulting in the variation of Δa-δ (crack growth law) and δ-Δa obtained for this steel. For new Δa values, corresponding δ values were first calculated from δ-Δa. Then, corresponding J values for the obtained δ values were calculated from the area under the F-δ record of a full-fractured specimen (with large displacement). Given Δa and J values for new data points, the developed J-Δa plot with extra data points yielded a satisfactory estimation of JIC=345kN/m with only a -3.1% error. This is promising and showed that the developed technique could ease the estimation of JIC significantly and reduce the time and cost of expensive extra fracture toughness tests.

Study on the Fracture Toughness of Wood Grown in Korea(I) - Mode I Fracture Thoughness - (국산재(國産材)의 파괴인성(破壞靭性)에 관한 연구(硏究)(I) - 모-드 I 파괴시(破壞時)의 파괴인성(破壞靭性) -)

  • Lee, Jun-Jae
    • Journal of the Korean Wood Science and Technology
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    • v.17 no.4
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    • pp.70-76
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    • 1989
  • The fracture toughness of two species, Pinus rigida MILL and Pinus koraiensis S. et Z. grown in Korea, was investigated by means of single edge notch beam specimen for the six principal systems of crack propagation in wood. The values of the fracture toughness for the LR and the LT systems ($K_{IC}$LR and $K_{IC}$LT) were found to be similar to each other and about 8 times greater than those for the other systems ($K_{IC}$RL, $K_{IC}$TL and $K_{IC}$TR) in both species. The results indicate that the characteristics of fracture toughness in three principal directions of wood (L, R, T direction) are quite different from those of bending strength for the responsible direction. To predict $K_{IC}$ value based on the variation of specific gravity, the experimental values of $K_{IC}$LT and $K_{IC}$TL were compared to the predicted values by published relationship between $K_{IC}$ and specific gravity. However, there were 10 to 25% differences between the former and the latter.

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The Effects of Immunocastration on Meat Quality and Sensory Properties of Pork Bellies

  • Jeong, Jong-Youn;Choi, Ji-Hun;Choi, Yun-Sang;Han, Doo-Jeong;Kim, Hack-Youn;Lee, Mi-Ai;Lee, Duk-Hun;Kim, Cheon-Jei
    • Food Science of Animal Resources
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    • v.31 no.3
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    • pp.372-380
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    • 2011
  • This study was conducted to assess meat quality and sensory properties of pork bellies from immunocastrated males (IC) compared to meat from surgically castrated males (SC), intact males (IM), and females (FE). Pork bellies from IC had significantly higher pH values than meat from either SC or FE. Pork bellies from IC showed lower CIE $L^*$ values than those from SC, but were redder (higher CIE $a^*$ values) than meat from SC or FE. However, no differences in visual color were observed between pork bellies from IC and SC pigs using National Pork Producer Council scales. Water holding capacity was higher in SC and FE than that in IC. IC showed no significant difference in cooking loss and shear force values compared with those of SC. Both SC and IC had improved fat content when compared to that in IM, and IC meat showed a similar fat content to that of FE. Pork bellies from IC showed higher ratings for all visual evaluation traits than those of SC and were the same as meat from FE. Boar odor was not significantly different among the treatments. IC was rated similar to SC for taste, tenderness, and overall acceptability.

Modified LOGIT(MLOGIT) Transformation: Prediction of $IC_{50}$ Value from Two Arbitrary Concentration Data

  • 유성은;차옥자
    • Bulletin of the Korean Chemical Society
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    • v.16 no.2
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    • pp.110-112
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    • 1995
  • A LOGIT transformation is a method to estimate IC50 values with two arbitrary concentration data when complete dose response curves(DRCs) are not available. We propose a modified LOGIT transformation (MLOGIT) which predicts IC50 values more accurately than the conventional LOGIT method.

Fracture Toughness of Wood Grown in Korea (II) - Mode I Fracture of Hardwoods - (국산재의 파괴인성에 관한 연구 (II) - 활엽수의 모-드 I 파괴 -)

  • Lee, Jun-Jae;Shim, Kug-Bo
    • Journal of the Korean Wood Science and Technology
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    • v.19 no.1
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    • pp.6-13
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    • 1991
  • Tests of notched specimens of ten hardwood species in the LR and LT systems were conducted to investigate fracture toughness($K_{IC}$) and effective moduli of elasticity(MOE). $K_{IC}$ values were examined in relation to MOR, MOE, specific gravity of clear wood specimens. It was found in both systems that there were significant relationship between $K_{IC}$ and MOR, $K_{IC}$ and specific gravity. To predict the effective MOE of notched specimen from MOE of clear wood, it was analyzed by using equvalent cross-section method. In LR system, the observed values were similar to the predicted values, but in LT system, both were not agreed as the ovserved values were smaller. However. the results were shown that this method was avaliable to predict the effective MOE of notched specimens.

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Design, Synthesis and Biological Evaluation of Novel Analogs of Bortezomib

  • Rao, R. Janaki Rama;Rao, A.K.S. Bhujanga;Swapna, K.;Rani, B. Baby;Kumar, S. Prasanna;Awantika, S.;Murthy, Y.L.N.
    • Journal of the Korean Chemical Society
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    • v.55 no.5
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    • pp.765-775
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    • 2011
  • Novel analogs of bortezomib were designed, synthesized and in vitro biological evaluation was carried out using human tumor cell lines A549 and PC3. Docking studies of these analogs of bortezomib was discussed. According to biological investigations, the inhibitors 4, 6, and 8 were found to be more potent than reference drug candidate bortezomib. A549 cell line showed significant sensitivity towards 4, 6, and 8 with $IC_{50}$ values 14.03, 18.5, and 12.4 nM, respectively, and PC3 cell line showed IC50 values 26.1, 37.0, and 21.2 nM, respectively. The $IC_{50}$ values of bortezomib in these cell lines are 27.3 nM and 42.0 nM.

J-Integral Evaluation of Concrete Fracture Characteristics

  • Choi, Sin-Ho;Kye, Hae-Ju;Kim, Wha-Jung
    • International Journal of Concrete Structures and Materials
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    • v.18 no.3E
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    • pp.183-189
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    • 2006
  • Many researchers have recently proposed various parameters, variables of models and experimental methods to evaluate fracture properties of concrete, and their developments allow us to analyze the non-linear and quasi-brittle fracture mechanisms. This paper presents a brief treatment of the fracture parameters. Additionally, three-point bending tests were conducted to compare J-integral($J_{Ic}$) with other parameters($K_{Ic},\;G_{Ic},\;and\;G_F$). The change in parameter values with respect to the width and notch length of concrete beam specimens was also considered. The load-displacement curves were used to measure the concrete fracture toughness experimentally. From the results of experiment, it was found that the value of $G_F\;and\;J_{Ic}$ decreased as the notch depth increased and that $G_F$ was less sensitive than $J_{Ic}$. Therefore, the former, $G_F$, is more appropriate in using it as the concrete fracture toughness parameter. The values of $G_F\;and\;J_{Ic}$ increased when the width of concrete specimens increasing from 75 mm to 150 mm. Thus, the effects of the specimen width should be considered in determining the fracture toughness of concrete.

Fracture Analysis of Electronic IC Package in Reflow Soldering Process

  • Yang, Ji-Hyuck;Lee, Kang-Yong;Lee, Taek sung;Zhao, She-Xu
    • Journal of Mechanical Science and Technology
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    • v.18 no.3
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    • pp.357-369
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    • 2004
  • The purposes of the paper are to analyze the fracture phenomenon by delamination and cracking when the encapsulant of plastic IC package with polyimide coating shows viscoelastic behavior under hygrothermal loading in the IR soldering process and to suggest more reliable design conditions by the approaches of stress analysis and fracture mechanics. The model is the plastic SOJ package with the polyimide coating surrounding chip and dimpled diepad. On the package without cracks, the optimum position and thickness of polyimide coating to decrease the maximum differences of strains at the bonding surfaces of parts of the package are studied. For the model delaminated fully between the chip and the dimpled diepad, C(t)-integral values are calculated for the various design variables. Finally, the optimal values of design variables to depress the delamination and crack growth in the plastic IC package are obtained.

NEAR-INFRARED PHOTOMETRY OF THE STAR CLUSTERS IN THE DWARF IRREGULAR GALAXY IC 5152

  • Kyeong, Jae-Mann;Sung, Eon-Chang;Kim, Sang-Chul;Sohn, Sang-Mo Tony;Sung, Hyun-Il
    • Journal of The Korean Astronomical Society
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    • v.39 no.4
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    • pp.89-94
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    • 2006
  • We present JHK-band near-infrared photometry of the star clusters in the dwarf irregular galaxy IC 5152. After excluding possible foreground stars, a number of candidate star clusters are identified in the near-infrared images of IC 5152, which include young populations. Especially, five young star clusters are identified in the(J-H, H-K) two color diagram and the total extinction values toward these clusters are estimated to be $A_v=2-6$ from the comparison with the theoretical values given by the Leitherer et al.(1999)'s theoretical star cluster model.