• Title/Summary/Keyword: J-T Analysis

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ANTI-PERIODIC SOLUTIONS FOR BAM NEURAL NETWORKS WITH MULTIPLE DELAYS ON TIME SCALES

  • Shu, Jiangye;Li, Yongkun
    • Journal of applied mathematics & informatics
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    • v.29 no.1_2
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    • pp.279-292
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    • 2011
  • In this paper, we consider anti-periodic solutions of the following BAM neural networks with multiple delays on time scales: $$\{{x^\Delta_i(t)=-a_i(t)e_i(x_i(t))+{\sum\limits^m_{j=1}}c_{ji}(t)f_j(y_j(t-{\tau}_{ji}))+I_i(t),\atop y^\Delta_j(t)=-b_j(t)h_j(y_j(t))+{\sum\limits^n_{i=1}}d_{ij}(t)g_i(x_i(t-{\delta}_{ij}))+J_j(t),}\$$ where i = 1, 2, ..., n,j = 1, 2, ..., m. Using some analysis skills and Lyapunov method, some sufficient conditions on the existence and exponential stability of the anti-periodic solution to the above system are established.

Qualification of J-R (J-T) Curve from 1/2T Compact-Tension Specimen (1/2T Compact-Tension Type 시편으로 구한 J-R (J-T) 곡선의 타당성 검토.)

  • Jee, Sae-Hwan;Park, Sun-Pil
    • Nuclear Engineering and Technology
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    • v.19 no.3
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    • pp.169-179
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    • 1987
  • The change of material J-R (J-T) curve with crack extension and J-calculation method was investigated to give experimental and analytical method for reliable J-R (J-T) curve, which was adapted recently as a tool for instability analysis of Nuclear Pressure Vessel. Experiments were carried out by Single Specimen Unloading Compliance Method using 1/2"T, Compact-Tension Type fracture mechanic specimens which were the same size and material as domestic nuclear pressure vessel material surveillance specimens. The results revealed that crack extension up to 25~30% of initial uncracked ligament and JD (Deformation theory J) calculation method, currently being used in NUREG-0744, could give rather reliable material J-R (J-T) curve than the small crack extension and JM (Modified J) calculation method. But as JM results more or less higher J at instability, the application of JM should be considered regarding to the problem of power plant availability.lity.

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Constraint of Semi-elliptical Surface Cracks in T and L-joints (T-형 및 L-형 배관내 반타원 표면균열에서의 구속상태)

  • Lee, Hyeong-Il
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.25 no.9
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    • pp.1325-1333
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    • 2001
  • Critical defects in pressure vessels and pipes are generally found in the form of a semi-elliptical surface crack, and the analysis of which is consequently an important problem in engineering fracture mechanics. Furthermore, in addition to the traditional single parameter K or J-integral, the second parameter like T-stress should be measured to quantify the constraint effect. In this work, the validity of the line-spring finite element is investigated by comparing line-spring J-T solutions to the reference 3D finite element J-T solutions. A full 3D-mesh generating program for semi-elliptical surface cracks is employed to provide such reference 3D solutions. Then some structural characteristics of the surface-cracked T and L-joints are studied by mixed mode line-spring finite element. Negative T-stresses observed in T and L-joints indicate the necessity of J-T two parameter approach for analyses of surface-cracked T and L-joints.

3D Semi-elliptical Interfacial Crack Front Stress Fields in Welded Joints (용접부 3차원 반타원 계면균열선단에서의 응력장)

  • 최호승;이형일;송원근
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.15 no.4
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    • pp.649-659
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    • 2002
  • For a variety of elastic-plastic stress fields of plane strain specimens, many research works verified the validity of J-T approach. To generalize the validity of J-T method, however, further investigations are needed for more practical 3D structures than the idealized geometries as plane strain specimens. In this work, selecting two main types of structures such as plate and straight pipe, we perform 3D finite element(FE) modeling, and accompanying elastic, elastic-plastic FE analyses. We then study the validity of J-T application to 3D structures, and present some useful informations for the design or assessment of pipe welds by comparing the stress fields from the detailed 3D FE analyses to those predicted with J-T two parameters.

An Estimation of Constraint Factor on the ${\delta}_t$ Relationship (J-적분과 균열선단개구변위에 관한 구속계수 m의 평가)

  • 장석기
    • Journal of Advanced Marine Engineering and Technology
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    • v.24 no.6
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    • pp.24-33
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    • 2000
  • This paper investigates the relationship between J-integral and crack tip opening displacement, ${\delta}_t$ using Gordens results of numerical analysis. Estimation were carried out for several strength levels such as ultimate, flow, yield, ultimate-flow, flow-yield stress to determine the influence of strain hardening and the ratio of crack length to width on the $J-{\delta}_t$ relationship. It was found that for SE(B) specimens, the $J-{\delta}_t$ relationship can be applied to relate J to ${\delta}_t$ as follows $J=m_j{\times}{\sigma}_i{\times}{\delta}_t$ where $m_j=1.27773+0.8307({\alpha}/W)$, ${\sigma}_i:{\sigma}_U$, ${\sigma}_{U-F}={\frac{1}{2}} ({\sigma}_U+{\sigma}_F$), ${\sigma}_F$, ${\sigma}_F}$ $Y=({\sigma}_F+{\sigma}_Y)$, ${\sigma}_Y$

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A report of 7 unrecorded bacterial species isolated from several Jeju soil samples in 2016

  • Kim, Ju-Young;Jang, Jun Hwee;Maeng, Soohyun;Kang, Myung-Suk;Kim, Myung Kyum
    • Journal of Species Research
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    • v.7 no.2
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    • pp.151-160
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    • 2018
  • Seven bacterial strains, 15J4M-1, 15J13-8, 16MFM10, 15J1-8, SR1-5-4, 15J13-6, and 15J8-11 assigned to the phylum Actinobacteria, Bacteroidetes, and Firmicutes were isolated from soil samples collected from Jeju, Korea. Phylogenetic analysis based on 16S rRNA gene sequence revealed that strains 15J4M-1, 15J13-8, 16MFM10, 15J1-8, SR1-5-4, 15J13-6, and 15J8-11 were most closely related to Bacillus selenatarsenatis $SF-1^T$ (with 99.4% similarity), Brevibacterium luteolum $CF87^T$ (99.5%), Carnobacterium iners CCUG $62000^T$ (99.6%), Exiguobacterium profundum $10C^T$ (99.3%), Larkinella insperata LMG $22510^T$ (99.3%), Pseudokineococcus lusitanus CECT $7306^T$ (99.4%), and Spirosoma endophyticum $EX36^T$ (99.3%), respectively. This is the first report of these seven species in Korea.

J-T Characterization of Stress Fields Along 3D Semi-Elliptical Interfacial Crack Front (J-T에 의한 3차원 반타원 계면균열선단 응력장의 기술)

  • Choi, Ho-Seung;Lee, Hyung-Yil
    • Transactions of the Korean Society of Mechanical Engineers A
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    • v.26 no.7
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    • pp.1250-1261
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    • 2002
  • Many research works have validated the J-T approach to elastic-plastic crack-tip stress fields in a variety of plane strain specimens. To generalize the validity of J-T method, further investigations are however needed for more practical 3D structures than the idealized plane strain specimens. In this work, we perform 3D finite element (FE) modeling of welded plate and straight pipe, and accompanying elastic, elastic-plastic FE analyses. Manual 3D modeling is almost prohibitive, since the models contain semi-elliptical interfacial cracks which require singular elements. To overcome this kind of barrier, we develop a program generating the meshes for semi-elliptical interfacial cracks. We then compare the detailed 3D FE stress fields to those predicted with J-T two parameters. Thereby we extend the validity of J-T application to 3D structures and infer some useful informations for the design or assessment of pipe welds.

Association of Sequence Variations in DGAT 1 Gene with Economic Traits in Hanwoo (Korea Cattle)

  • Kong, H.S.;Oh, J.D.;Lee, J.H.;Yoon, D.H.;Choi, Y.H.;Cho, B.W.;Lee, H.K.;Jeon, G.J.
    • Asian-Australasian Journal of Animal Sciences
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    • v.20 no.6
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    • pp.817-820
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    • 2007
  • The effects of diacylglycerol O-acyltransferase (DGAT1) candidate gene polymorphism on the economic traits of Hanwoo were studied. Through sequencing analysis, two polymorphism sites at K232A and T11993C were established and were analyzed by PCR-RFLP. The PCR-RFLP analysis for K232A showed that the frequencies of alleles K and A were 0.75 and 0.25, respectively, and the frequencies of genotypes for K/K, K/A and A/A were estimated as 0.509, 0.491 and 0, respectively. In the PCR-RFLP analysis for T11993C, we found allele frequencies of 0.773 and 0.227 for T and A, respectively, and 0.546, 0.454 and 0 for the T/T, T/C and C/C genotype frequencies, respectively. No significant effects on economic traits in Hanwoo were found in the separate analysis of K232A and T11993C polymorphisms, but the interaction between K232A and T11993C showed a significant effect (p<0.005) on marbling score. The DGAT1 candidate gene was found to have a significant effect not only on milk yield and component traits but also on the metabolism of intramuscular fat.

HOT CHANNEL ANALYSIS CAPABILITY OF THE BEST-ESTIMATE MULTI-DIMENSIONAL SYSTEM CODE, MARS 3.0

  • JEONG J.-J.;BAE S. W.;HWANG D. H.;LEE W. J.;CHUNG B. D.
    • Nuclear Engineering and Technology
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    • v.37 no.5
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    • pp.469-478
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    • 2005
  • The subchannel analysis capability of MARS, a multi-dimensional thermal-hydraulic system code, has been enhanced. In particular, the turbulent mixing and void drift models for the flow-mixing phenomena in rod bundles were improved. Then, the subchannel analysis feature was combined with the existing coupled system thermal-hydraulics (T/H) and 3D reactor kinetics calculation capability of MARS. These features allow for more realistic simulations of both the hot channel behavior and the global system T/H behavior. Using the coupled features of MARS, a coupled analysis of a main steam line break (MSLB) is carried out for demonstration purposes. The results of the calculations are very reasonable and promising.