• Title/Summary/Keyword: Initial Strain

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Leuconostoc mesenteroides CJNU 0147 and Lactobacillus casei CJNU 0588 Improve Growth of a Bifidobacterium lactis Strain in Co-cultures

  • Eom, Ji-Eun;Moon, Gi-Seong
    • Preventive Nutrition and Food Science
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    • v.16 no.4
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    • pp.386-389
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    • 2011
  • Previous studies have confirmed that fermented whey produced by Leuconostoc mesenteroides CJNU 0147 or Lactobacillus casei CJNU 0588 display bifidogenic growth stimulator (BGS) activity. The present study sought to determine if the strain itself can improve the growth of bifidobacteria in co-cultures. In reinforced clostridial medium (RCM), both strains stimulated the growth of a Bifidobacterium lactis strain during the exponential phase and also stimulated the growth during almost all growth phases in whey broth. Fermented whey containing viable Leu. mesenteroides CJNU 0147 and L. casei CJNU 0588 cells maintained viability of the B. lactis strain stored at $10^{\circ}C$ in MRS broth. Viable cell count of the B. lactis strain without the fermented whey was decreased to 5.6 log cfu/mL after 15 days, whereas that of the strain with the fermented whey was slightly increased to 7.1 log cfu/mL as compared with initial viable cell count of 6.9 log cfu/mL.

A Study on the Constitutive Behavior of Undisturbed Weathered Soils at Small-to-Large Strain Conditions (미소변형률 및 대변형률 조건에서 불교란 풍화토의 구성거동에 관한 연구)

  • 오세붕;이영휘;안영대
    • Proceedings of the Korean Geotechical Society Conference
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    • 2001.03a
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    • pp.139-146
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    • 2001
  • Undrained triaxial tests were peformed for a weathered soil, which includes local measurement using LVDT The behavior from small In large strain conditions could be evaluated consistently through a triaxial test, The stress-strain relationship of undisturbed samples were compared with the disturbed and the shear moduli in the small strain level had the almost same values. Especially the shear moduli were mostly affected by the initial condition of water contents. An anisotropic hardening model based on the total stress concept could predict the stress-strain relationship accurately, which makes it possible to analyze the geotechnical problem reasonably for the weathered soil.

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A new approach for the cylindrical cavity expansion problem incorporating deformation dependent of intermediate principal stress

  • Zou, Jin-Feng;Xia, Ming-yao
    • Geomechanics and Engineering
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    • v.12 no.3
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    • pp.347-360
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    • 2017
  • The problem of cylindrical cavity expansion incorporating deformation dependent of intermediate principal stress in rock or soil mass is investigated in the paper. Assumptions that the initial axial total strain is a non-zero constant and the axial plastic strain is not zero are defined to obtain the numerical solution of strain which incorporates deformation-dependent intermediate principal stress. The numerical solution of plastic strains are achieved by the 3-D plastic potential functions based on the M-C and generalized H-B failure criteria, respectively. The intermediate principal stress is derived with the Hook's law and plastic strains. Solution of limited expansion pressure, stress and strain during cylindrical cavity expanding are given and the corresponding calculation approaches are also presented, which the axial stress and strain are incorporated. Validation of the proposed approach is conducted by the published results.

The Shear Stiffness of Small Strain with Time Effect (미소변형 전단강성에 시간효과가 미치는 영향)

  • 김수삼;신현영;김병일
    • Proceedings of the KSR Conference
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    • 2001.05a
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    • pp.249-256
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    • 2001
  • This study investigated the shear stiffness of level of small strain with time effect. Time effect consists of rest time, loading rate of recent and current stress path. In addition, for the measurement of small strain, overconsolidated state was represented in a triaxial cell, and drained stress path tests were carried out. Test results show that the loading rate of recent stress path has no effects on the stiffness of very small strain, but the shear stiffness of level of small strain increases with it. Finally, the rest time and the loading rate of current stress path have the effects on the shear stiffness of initial and small strain.

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Computational modelling for description of rubber-like materials with permanent deformation under cyclic loading

  • Guo, Z.Q.;Sluys, L.J.
    • Interaction and multiscale mechanics
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    • v.1 no.3
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    • pp.317-328
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    • 2008
  • When carbon-filled rubber specimens are subjected to cyclic loading, they do not return to their initial state after loading and subsequent unloading, but exhibit a residual strain or permanent deformation. We propose a specific form of the pseudo-elastic energy function to represent cyclic loading for incompressible, isotropic materials with stress softening and residual strain. The essence of the pseudo-elasticity theory is that material behaviour in the primary loading path is described by a common elastic strain energy function, and in unloading, reloading or secondary unloading paths by a different strain energy function. The switch between strain energy functions is controlled by the incorporation of a damage variable into the strain energy function. An extra term is added to describe the permanent deformation. The finite element implementation of the proposed model is presented in this paper. All parameters in the proposed model and elastic law can be easily estimated based on experimental data. The numerical analyses show that the results are in good agreement with experimental data.

STUDIES OF EFFECTS ON COPPER RESISTANCE IN YEAST AS INFLUENCED BY DESOXYRIBONUCLEATES (Saccharomyces cereisiase의 동저항변이에 미치는 DNA의 영향에 관한 연구)

  • 이민재
    • Journal of Plant Biology
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    • v.1 no.1
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    • pp.1-6
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    • 1958
  • 1. Study was made to investigate effects of desoxyribonucleates on copper-resistance in yeast. 2. It is found that the resistant strain there exists the phenomic lag. 3. In the occurrence of the resistant strain there exists the phenomic lag. 4. Desoxyribonucleate isolated from copper resistant culture is capable of inducing the resistant strain, which is the same type as donor of the resistant type. It accelerated the rate of variation to the resistant, but it is of no effect on the resistant strain. 5. Desoxyribonucleate derived from non-resistant type inhibits growth of the resistant strain and delays the initial phase of growth. However, it is of no effect on the sensitive strain. It is concluded that desoxyribonucleate derived from resistant culture is capable of inducing the resistance, however, nonresistant type desoxyribonucleate is of no effect on inducing the resistance.

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Evaluation of Flow Stress of Metal up to High Strain (금속소재의 고변형률 영역 유동응력선도 평가)

  • Lee, S.K.;Lee, I.K.;Lee, S.Y.;Lee, S.M.;Jeong, M.S.
    • Transactions of Materials Processing
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    • v.29 no.6
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    • pp.316-322
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    • 2020
  • The flow stress curve is usually determined via uniaxial tensile or simple compression test. However, the flow stress curve up to high strain cannot be obtained using these two tests. This study presents a simple method for obtaining the flow stress curve up to high strain via FE analysis, a simple compression test, and an indentation test. In order to draw the flow stress curve up to high strain, the indentation test was carried out with the pre-stained specimen using the simple compression test. The flow stress curve of Al6110 was evaluated up to high strain using the proposed method, and the result was compared with the flow stress curve of the uniaxial tensile test of the initial material.

Real-time Tensile Strain Measurement System based on ArUco Marker (ArUco 마커 기반 실시간 인장변형률 측정 시스템)

  • Lee, Seung-Ah;Kim, Dohyeon;Kim, Yoon
    • Journal of Korea Multimedia Society
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    • v.24 no.6
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    • pp.753-759
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    • 2021
  • During tensile test, tensile strain of tensile tester is measured by movement distance of upper zig and initial specimen's length. Conventional tensile tester program obtains the tensile strain after the end of the test, however the method is not appropriate in real time because the results are calculated until the test is finished. We suggest a real-time measurement system of tensile strain using ArUco Marker in OpenCV library. The system is designed to detect marker attached on the upper zig and calculate specimen's tensile strain. According to comparison of the calculated data and the results of the tester, errors approximately showed 0.128 mm on 3840×2160 video resolution.