• Computers and Concrete
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• 제15권2호
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• pp.183-198
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• 2015

Chloride ingress implies a complex interaction between physical and chemical process, in which heat, moisture and chloride ions transport through concrete cover. Meanwhile, reinforced concrete structure itself undergoes evolution due to variation in temperature, relative humidity and creep effects, which can potentially change the deformation and trigger some micro-cracks in concrete. In addition, all of these process show time-dependent performance with complex interaction between structures and environments. In the present work, a time-dependent behavior of chloride transport in reinforced concrete beam subjected to flexural load is proposed based on the well-known section fiber model. The strain state varies because of stress redistribution caused by the interaction between environment and structure, mainly dominated by thermal stresses and shrinkage stress and creep. Finally, in order to clear the influence of strain state on the chloride diffusivity, experiment test were carried out and a power function used to describe this influence is proposed.

• The Journal of Korean Physical Therapy
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• 제31권4호
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• pp.254-259
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• 2019

Purpose: This study examined the interactions between the job strain and social support in the workplace on the development of workrelated neck pain in office workers. Methods: The participants included 62 office workers without neck pain over the last twelve months. A battery of measures evaluating the potential workplace risk factors in office settings were conducted at the baseline, and at the 12 month incidence of work-related neck pain was reported via monthly questionnaires. Survival analysis evaluated the interaction effect between job strain and social support on the development of work-related neck pain. Results: The incidence of work-related neck pain was 1.91 (95% CI: 1.06 - 3.45) per 100 person months. The interaction effect between job strain and social support found that job strain may increase the risk of developing new work-related neck pain when lower social support existed in the workplace. On the other hand, the adverse effects of job strain on the development of neck pain were not significant when workers had higher social support from their colleagues and supervisors. Conclusion: An investigation of the moderating effects of risk factors on neck pain might reveal the unexplained relationship between the risk factors for the development of neck pain in office workers. Therefore, the interest in prevention plans and treatments should involve a comprehensive understanding of the risk factors at workplace.

• 한국연소학회지
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• 제21권4호
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• pp.48-60
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• 2016

Experimental and numerical studies were conducted to investigate flame behaviors near flammable limits for downstream-interacting SNG-air premixed flames in a counter-flow configuration. The SNG fuel consisted of a methane, a propane, and a hydrogen with volumetric ratios of 91, 6, and 3%, respectively. The most appropriate priority for some reliable reaction mechanisms examined was given to the mechanism of UC San diego via comparison of lean extinction limits attained numerically with experimental ones. Flame stability map was presented with a functional dependencies of lower and upper methane concentrations in terms of global strain rate. The results show that, at the global strain rate of $30s^{-1}$, lean extinction boundary is slanted while rich extinction one is relatively less inclined because of the dependency of such extinction boundary shapes on deficient reactant Lewis number governed by methane mainly. Further increase of global strain rate forces both extinction boundaries to be more slanted and to be shrunk, resulting in an island of extinction boundary and subsequently one flame extinction limit. Extinction mechanisms for lean and rich, symmetric and asymmetric extinction boundary were identified and discussed via heat losses and chemical interaction.

• Journal of Magnetics
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• 제20권1호
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• pp.11-20
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• 2015

In this work, Monte Carlo simulation was employed to model the stretchable Ising monolayer film to investigate the effect of the spatial distance variation among magnetic atoms on magnetic behavior of the film. The exchange interaction was considered as functions of initial interatomic distance and the stretched distance (or the strain). Following Bethe-Slater picture, the magnetic exchange interaction took the Lennard-Jones potential-like function. Monte Carlo simulations via the Wolff and Metropolis algorithms were used to update the spin systems, where equilibrium and dynamic magnetic profiles were collected. From the results, the strain was found to have strong influences on magnetic behavior, especially the critical behavior. Specifically, the phase transition point was found to either increase or decrease depending on how the exchange interaction shifts (i.e. towards or away from the maximum value). In addition, empirical functions which predict how the critical temperatures scale with initial interatomic distance and the strain were proposed, which provides qualitatively view how to fine tune the magnetic critical point in monolayer film using the substrate modification induced strain.

• The Korean Journal of Physiology and Pharmacology
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• 제24권1호
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• pp.53-68
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• 2020

The purpose of this study was to characterize the genetic contribution to endothelial adaptation to exercise training. Vasoreactivity was assessed in aortas from four inbred mouse strains (129S1, B6, NON, and SJL) after 4 weeks of moderate intensity continuous exercise training (MOD), high intensity interval training (HIT) or in sedentary controls (SED). Intrinsic variations in endothelium-dependent vasorelaxation (EDR) to acetylcholine (ACh) as well as vasocontractile responses were observed across SED groups. For responses to exercise training, there was a significant interaction between mouse strain and training intensity on EDR. Exercise training had no effect on EDR in aortas from 129S1 and B6 mice. In NON, EDR was improved in aortas from MOD and HIT compared with respective SED, accompanied by diminished responses to PE in those groups. Interestingly, EDR was impaired in aorta from SJL HIT compared with SED. The transcriptional activation of endothelial genes was also influenced by the interaction between mouse strain and training intensity. The number of genes altered by HIT was greater than MOD, and there was little overlap between genes altered by HIT and MOD. HIT was associated with gene pathways for inflammatory responses. NON MOD genes showed enrichment for vessel growth pathways. These findings indicate that exercise training has non-uniform effects on endothelial function and transcriptional activation of endothelial genes depending on the interaction between genetic background and training intensity.

• 한국자동차공학회논문집
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• 제9권6호
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• pp.135-142
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• 2001

The effect of tensile hold time on the creep-fatigue interaction in AISI 316 stainless steel was investigated. To study the fatigue characteristics of the material, strain controlled low cycle fatigue(LCF) tests were carried out under the continuous triangular waveshape with three different total strain ranges of 1.0%, 1.5% and 2.0%. To study the creep-fatigue interaction, 5min., 10min., and 30min. of tensile hold times were applied to the continuous triangular waveshape with the same three total strain ranges. The creep-fatigue life was found to be the longest when the 5min. tensile hold time was applied and was the shortest when the 30min. tensile hold time was applied. The cause fur the shortest creep-fatigue life under the 30min. tensile hold time is believed to be the effect of the increased creep damage per cycle as the hold time increases. The creep-fatigue life prediction using artificial neural network(ANN) showed closer prediction values to the experimental values than by the modified Coffin-Manson method.

• Journal of Microbiology and Biotechnology
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• 제26권8호
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• pp.1439-1445
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• 2016

A yellow, rod-shaped, non-motile, gram-negative, and strictly aerobic bacterial strain, designated LPB0005^T, was isolated from a marine gastropod, Reichia luteostoma. Here the genome sequence was determined, which comprised 3,395,737 bp with 2,962 protein-coding genes. The DNA G+C content was 36.3 mol%. The 16S rRNA gene sequence analysis indicated that the isolate represents a novel genus and species in the family Flavobacteriaceae, with relatively low sequence similarities to other closely related genera. The isolate showed chemotaxonomic properties within the range reported for the family Flavobacteriaceae, but possesses many physiological and biochemical characteristics that distinguished it from species in the closely related genera Ulvibacter, Jejudonia, and Aureitalea. Based on phylogenetic, phenotypic, and genomic analyses, strain LPB0005^T represents a novel genus and species, for which the name Cochleicola gelatinilyticus gen. nov., sp. nov. is proposed. The type strain is LPB0005^T (= KACC 18693^T = JCM 31218^T).

• 한국연소학회지
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• 제4권1호
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• pp.131-139
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• 1999

A Numerical Analysis of NOx production in Hydrogen-Air flame is performed using the quasi-laminar reaction modelling. As results, in low global strain rate region, $U_F/D_F\;{\leq}\;50,000$, the quasi-laminar reaction modelling reproduces the experimentally observed EINOx half power scaling that the ratio of EINOx and flame residence time, $L_f^3(D_F^2U_F)$, is proportional to the square root of global strain rate. Thus, it suggests that turbulence-chemistry interaction has a minor impact on the trend of NOx production in low global strain rate region. However, the quasi-laminar reaction modelling predicts the higher temperature and NOx than experimentally observed. This overprediction may be due to the lack of radiation and quasi-laminar reaction modelling.

• 한국해양공학회지
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• 제16권3호
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• pp.59-64
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• 2002

In the present study, we examined the influence of prestrain on creep strength of Class M alloy(STS310S) and Class A(STS310J1TB) alloys containing precipitates. Prestrain was given by prior creep at a higher stress than the following creep stresses. Creep behaviour before and after stress change and creep rate of pre-strained specimens were compared with that of virgin specimens. Pre-straining produced the strain region where the strain rate was lower than that of a virgin specimen both for STS310J1TB and STS310S steels. The reason for this phenomenon was ascribable to the viscous motion of dislocations, the interaction between dislocations and precipitates in a STS310J1TB steel, and the interaction of dislocations with sub-boundaries in a STS310S steen which has the higher dislocation density and smaller subgrain size resulted from pre-straining at higher stress.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
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• pp.1048-1050
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• 2017

본 연구에는 핀틀 노즐의 열변형 영향을 평가하기 위해 단방향 유체-구조 연성해석을 수행하였다. 단방향 유체-구조 연성해석을 위해 핀틀-노즐의 내부에 발생하는 압력 및 온도분포를 유동해석을 통해 도출하였고, 압력 및 온도분포 값을 각각의 유체-구조 해석의 하중조건으로 적용하여 핀틀의 변형량을 확인하였다. 변형에 대한 추력특성 변화를 확인하기 위해 양방향 유체-구조 연성해석을 수행 중이다.