• Computers and Concrete
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• v.25 no.1
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• pp.67-73
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• 2020

Traditionally used analytical approach to predict the fatigue failure of reinforced concrete (RC) structure is generally conservative and has certain limitations. The nonlinear finite element method (FEM) offers less expensive solution for fatigue analysis with sufficient accuracy. However, the conventional implicit dynamic analysis is very expensive for high level computation. Whereas, an explicit dynamic analysis approach offers a computationally operative modelling to predict true responses of a structural element under periodic loading and might be perfectly matched to accomplish long life fatigue computations. Hence, this study simulates the fatigue behaviour of RC beams with finite element (FE) assemblage presenting a simplified explicit dynamic numerical solution to show computer aided fatigue behaviour of RC beam. A commercial FEM package, ABAQUS has been chosen for this complex modelling. The concrete has been modelled as a 8-node solid element providing competent compression hardening and tension stiffening. The steel reinforcements are simulated as two-node truss elements comprising elasto-plastic stress-strain behaviour. All the possible nonlinearities are duly incorporated. Time domain analysis has been adopted through an automatic Newmark-β time incremental technique. The program consists of twelve RC beams to visualize the real behaviour during fatigue process and to obtain the reliability of the study. Both the numerical and experimental results indicate a redistribution of stresses along the time and damage accumulation of beam which severely affect the serviceability and ultimate capacity of RC beam. The output of the FEM analysis demonstrates good match with the experimental consequences which affirm the efficacy of the computer aided model. The controlled fatigue damage evolution at service fatigue load limits makes the FE model an efficient tool in predicting high cycle fatigue behaviour of RC structures.

• Journal of the Korean Society for Railway
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• v.17 no.2
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• pp.123-132
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• 2014

In this study, permanent deformation of asphalt trackbed was investigated by performing repetitive load test on specimen made with dense graded asphalt mixture that was specially prepared for asphalt trackbed foundation. The obtained test results were compared with those computed from the prediction model proposed by AASHTO 2002, called MEPDG. No prediction model adaptable only for permanent deformation of the asphalt trackbed foundation has yet been developed, so the prediction model by AASHTO was adapted in this study to simulate permanent deformation of trackbed foundations in asphalt slab track and in ballasted asphalt track. In order to simulate permanent deformation, a finite element analysis was performed to obtain stresses generated in trackbed due to wheel load. It was found that the predicted permanent deformation was much smaller than the anticipated deformation and that the asphalt track could be stable during the service life of the structure.

• Molecules and Cells
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• v.43 no.7
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• pp.645-661
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• 2020

Leaf senescence is a developmental process by which a plant actively remobilizes nutrients from aged and photosynthetically inefficient leaves to young growing ones by disassembling organelles and degrading macromolecules. Senescence is accelerated by age and environmental stresses such as prolonged darkness. Phytochrome B (phyB) inhibits leaf senescence by inhibiting phytochrome-interacting factor 4 (PIF4) and PIF5 in prolonged darkness. However, it remains unknown whether phyB mediates the temperature signal that regulates leaf senescence. We found the light-activated form of phyB (Pfr) remains active at least four days after a transfer to darkness at 20℃ but is inactivated more rapidly at 28℃. This faster inactivation of Pfr further increases PIF4 protein levels at the higher ambient temperature. In addition, PIF4 mRNA levels rise faster after the transfer to darkness at high ambient temperature via a mechanism that depends on ELF3 but not phyB. Increased PIF4 protein then binds to the ORE1 promoter and activates its expression together with ABA and ethylene signaling, accelerating leaf senescence at high ambient temperature. Our results support a role for the phy-PIF signaling module in integrating not only light signaling but also temperature signaling in the regulation of leaf senescence.

• Food Science of Animal Resources
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• v.34 no.3
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• pp.307-315
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• 2014

pH adjustment would be of advantage in improving the water holding capacity of muscle proteins. The objective of this study was to evaluate the addition of fish sarcoplasmic protein (SP) solution, which was adjusted to pH 3.0 or 12.0, neutralized to pH 7.0, and lyophilized to obtain the acid- and alkaline-treated SP samples, on the functional properties of the chicken myofibrillar protein induced by microbial transglutaminase (MTG). The solubility of alkaline-treated SP was higher than that of the acid counterpart; however, those values of the two pH-treated samples were lower than that of normal SP (p<0.05). All SP solutions were mixed with myofibrillar proteins (MP) extracted from chicken breast, and incubated with MTG. The shear stresses of MP with acid- and alkaline-treated SP were higher than that of normal SP. The thermal stability of MP mixture reduced upon adding SP, regardless of the pH treatment. The breaking force of MP gels with acid-treated SP increased more than those of alkaline-treated SP, while normal SP showed the highest value. The MP gel lightness increased, but cooking loss reduced, with the addition of SP. Smooth microstructure of the gel surface was observed. These results indicated that adjusting the pH of SP improved the water holding capacity of chicken myofibrillar proteins induced by MTG.

• The Journal of the Korea Contents Association
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• v.14 no.9
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• pp.311-320
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• 2014

This study attempted to find out the moderating effects of ego-resilience in the relationship between soldier's military stress and military adjustment. The datas were collected from 321 soldier of military from questionaries in October, 2013. The results were as follows. The soldier level and academic career had no impact on the military adjustment. Military stresses of soldier had greater impact on the military adjustment than other factors. Ego-resilience also had positive impact on the military adjustment. This study demonstrated that ego-resilience of soldier had moderating effect in the relationship between military stress and military adjustment. This study verified that to improve the capability of military adjustment of soldier it is as important to attention soldier's inside thing, ego-resilience as environment things. Finally, the authors remarked the limits of this study and the suggestions for the further research directions.

• The Journal of the Korea Contents Association
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• v.13 no.4
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• pp.497-507
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• 2013

According to increasing smartphone users, Public mobile services is expanding across all areas, including education. We have to prepare NEIS(National Education Information System) student and parent service based on smartphone that provide information about student's school life for the smartphone users. Therefore, in this paper, we conducted an online questionnaire survey for student and parent. User's perception for existing services were analyzed by factors of content availability, service utilization, and user affinity. Reliability analysis of the collected data, the results of correlation analysis, and multiple regression analysis were found reliable. The user affinity factor have the most significant impact on user satisfaction and intention to user smartphone service. Consequently, the study stresses a measure of NEIS student and parent service based on smartphone and public education information service through the perception analysis of these.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.29 no.12
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• pp.654-662
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• 2017

When emergency core cooling system (ECCS) is operated during loss of coolant accident (LOCA) in a pressurized water reactor (PWR), pressurized thermal shock (PTS) phenomenon can occur as cooling water is injected into a cold leg, mixed with hot primary coolant, and then entrained into a reactor vessel. Insufficient flow mixing may cause temperature stratification and steam condensation. In addition, flow vibration may cause thermal stresses in surrounding structures. This will reduce the life of the reactor vessel. Due to the importance of PTS phenomenon, in this study, calculation was performed for Test 1 among six types of OECD/NEA ROSA tests with ANSYS CFX R.17. Predicted results were then compared to measured data. Additionally, because temperature difference between the hot coolant at the inlet of the cold leg and the cold cooling water at the inlet of the ECCS injection line is 200 K or more, buoyancy force due to density difference might have significant effect on thermal-hydraulic characteristics of flow. Therefore, in this study, the necessity to include buoyancy force term in governing equations for accurate prediction of single phase thermal stratification in both cold legs and downcomer by ECCS injection was numerically studied.

• Korean Journal of Child Studies
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• v.33 no.3
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• pp.83-97
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• 2012

The purpose of this study is to investigate the effects of sand play therapy on the parenting stress and saliva cortisol levels of parents undergoing child counseling programs. The study was conducted with 13 parents who were undergoing child counseling programs. The sessions were held every week for 45 minutes from July, 2011 to September, 2011. To evaluate the effects of sand play therapy, pre test and post test were conducted and the results were then analyzed. The therapy sessions consist of parents making sand boxes, and this was done without consideration of any particular theme. The instrument used was Abidin (1990)'s Parenting Stress Instrument (PSI). Saliva cortisol levels were obtained at the pre-post stage of the sand play therapy. The data were analyzed by means of frequency and the Wilcoxon Rank Sum Test was conducted by the SPSS. The major findings were as follows; There were significant differences in terms of the decreases in the areas of perception of all the parenting stresses examined, including daily life stress, child temperament stress, child relationship stress, and learning-expectation stress, as well as in saliva cortisol levels. Finally, this study suggests that parenting stress and saliva cortisol levels have a positive relationship, and the effects of sand play therapy were significant with decreases in parenting stress and saliva cortisol levels. There is a clear need for parents undergoing child counseling programs to engage in sand play therapy to decrease parenting stress and saliva cortisol levels.

• Journal of the Korean Geographical Society
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• v.51 no.3
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• pp.421-439
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• 2016

Global society is shifting and now evolving towards glocalization, meaning the increasing role of region and multi scalar interactions between region and global social world. In this glocalization era, there has been mushrooming literature and much discussions on the impacts of place-branding and place-marketing on regional development both in academia and practical researches. The inclusive and participatory creative place-making process, however, is more quintessential than the resultant place marketing strategy. This paper tries to reassess the creative place-making based on culture-led regional development perspectives. Specifically it compares Korea and Japan's strategies and suggests a hybrid model of place-making-branding-marketing, utilizing cultural content industries. It then stresses the importance of building a virtuous circle of sustainable regional cultural industrial ecosystem including culture-based interpretation of places and improvement of community quality of life.

• Smart Structures and Systems
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• v.26 no.3
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• pp.319-329
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• 2020

Structural damage to an arch dam is often of major concern and must be evaluated for probable rehabilitation to ensure safe, regular, normal operation. This evaluation is crucial to prevent any catastrophic or failure consequences for the life time of the dam. If specific major damage such as a large crack occurs to the dam body, the assessments will be necessary to determine the current level of safety and predict the resistance of the structure to various future loading such as earthquakes, etc. This study investigates the behavior of an arch dam cracked due to water pressure. Safety factors (SFs), of shear and compressive tractions were calculated at the surfaces of the contraction joints and the cracks. The results indicated that for cracking with an extension depth of half the thickness of the dam body, for both cases of penetration and non-penetration of water load into the cracks, SFs only slightly reduces. However, in case of increasing the depth of crack extension into the entire thickness of the dam body, the friction angle of the cracked surface is crucial; however, if it reduces, the normal loading SFs of stresses and joints tractions reduce significantly.