• Structural Engineering and Mechanics
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• v.81 no.3
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• pp.367-378
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• 2022

In this study, combined size and shape optimization of spatial truss tower structures are presented by using new optimization algorithms named Rao-1, and Rao-2. The nodal displacements, allowable stress and buckling for compressive members are taken into account as structural constraints for truss towers. The discrete and continuous design variables are used as design variables for size and shape optimization. To show the efficiency of the proposed optimization algorithm, 25-bar, and 39-bar 3D truss towers are solved for combined size and shape optimization. The 72-bar, and 160-bar 3D truss towers are solved only by size optimization. The optimal results obtained from this study are compared to those given in the literature to illustrate the efficiency and robustness of the proposed algorithm. The structural analysis and the optimization process are coded in MATLAB programming.

• Journal of Ship and Ocean Technology
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• v.9 no.4
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• pp.11-22
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• 2005

This paper addresses details of wave load nonlinearity effect on stress RAO and damage ratio using component stochastic fatigue analysis. Traditional spectral fatigue analysis for ship structure is based on linear theory; however, there are a number of nonlinearity sources. Especially loading nonlinearity, such as hydrodynamic pressure applying to ship side and gravity changes due to roll and pitch motion, is thought to critically violate the linearity assumption of spectral fatigue analysis, which involves stress RAO as linear parameter. The main focus is placed on how to idealize complicated characteristics of loading nonlinearity and how to implement the nonlinear bias to linear spectral fatigue analysis.

• Journal of muscle and joint health
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• v.28 no.1
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• pp.61-69
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• 2021

Purpose: This study investigated the mediating effect of perceived stress in the relationship between subjective health and depression in patients with coronary artery disease. Methods: This secondary analysis study used data from the 2016-2018 Korea National Health and Nutrition Examination Survey (KNHANES). Study participants included 466 patients over 20 years of age with coronary artery disease. Measures included questions about general characteristics, subjective health, perceived stress, and depression. The data were analyzed using complex sample design, descriptive analysis, Rao-Scott ��2 statistic, and multivariate logistic regression analysis with the SPSS 24.0 program. Results: Subjective health influenced depression, and perceived stress partially mediated it. Conclusion: To prevent depression in patients with coronary artery disease, it is necessary to develop effective stress management strategies.

• East Asian Journal of Business Economics (EAJBE)
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• v.2 no.2
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• pp.48-52
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• 2014

T In this paper we will observe the critical impact of the changing lifestyles and advancements in various fields of life. Terms like stress, anxiety, hyper tensions are now a days are being commonly associated with today's living patterns. Stress levels are demonstrating a very positive trend across all the demographic profiles of India. Youth is the soft target of this fatal movement. Indian youth is unable to face the challenges of demanding lives and is falling easy prey to the circumstances. There is a steep rise in youth suicide cases all across India.

• Research in Community and Public Health Nursing
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• v.26 no.2
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• pp.169-177
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• 2015

Purpose: Previous studies focused on the negative effects of Internet use such as obesity, depression, and addiction. However, few studies investigated whether the Internet use for an appropriate time has positive effects on adolescents' health. Thus, the purpose of the study was to examine the dose-response relationship between Internet use for non-academic purposes (NAP) and happiness/stress in adolescents. Methods: This study used data from the 2013 Korea Youth Risk Behavior Web-Based Survey. A total of 72,435 adolescents were included. Rao-Scott ${\chi}^2$ and multiple logistic regression were conducted. To test the dose-response relationship, this study examined how happiness/stress changed with increase in the time of Internet use for NAP. Results: After controlling for general characteristics, the odds ratios for being unhappy and stressful were lowest in adolescents using the Internet for NAP for more than 0 hour and less than an hour a day. Interestingly, students who did not use the Internet for NAP had a significantly higher risk of being unhappy/stressful than those using for more than 0 hour and less than an hour a day. Conclusion: Internet use for NAP for more than 0 hour and less than an hour a day has positive effects on happiness/stress in adolescents.

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.122-128
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• 2003

Rock bolts are widely used as a supplementary roof support system in hard-rock mining since a long time. Since the performance of fully grouted passive bolts depends on bond strength, in the present investigation extensive laboratory pull-out as well as push-out tests were conducted varying the bolt diameter, length and cement-water mixing ratios of grout. The load-displacement curves were developed and were verified with the numerical results obtained from finite element analysis using ALGOR software. Numerical models were validated for push-out tests and a detailed analysis was carried out to know the displacement, stress, strain distribution along the bolt.

• 유체기계공업학회:학술대회논문집
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• 1998.02a
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• pp.11-28
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• 1998

Crack initiation and propagation of blades is a serious matter in turbomachinery. Outages are common due to these problems that occur during the service of the machine resulting in a huge loss of revenue. Once in a while, the problems become serious and cause major shutdowns which can in some cases result in the loss of the whole machine in a catastrophic manner. In this presentation, we will discuss the crack initiation studies of a hydraulic machine runner blade by local stress strain approach and crack propagation at the root of a low pressure stage steam turbine blade by means of stress intensity factor approach. In both the cases, we will show how the present day technologies can predict actual field observations.

• Plant Biotechnology Reports
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• v.5 no.1
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• pp.19-25
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• 2011

Tocopherols belong to the plant-derived poly phenolic compounds known for antioxidant functions in plants and animals. Activation of mitogen-activated protein kinases (MAPK) is a common reaction of plant cells in defense-related signal transduction pathways. We report a novel non-antioxidant function of ${\alpha}$-tocopherol in higher plants linking the physiological role of tocopherol with stress signalling pathways. Pre-incubation of a low concentration of $50{\mu}M$ ${\alpha}$-tocopherol negatively interferes with MAPK activation in elicitor-treated tobacco BY2 suspension culture cells and wounded tobacco leaves, whereas pre-incubated BY2 cells with ${\alpha}$-tocopherol phosphate did not show the inhibitory effect on stimuli-induced MAPK activation. The decreased MAPK activity was neither due to a direct inhibitory effect of ${\alpha}$-tocopherol nor due to the induction of an inhibitory or inactivating activity directly affecting MAPK activity. The data support that the target of ${\alpha}$-tocopherol negatively regulates an upstream component of the signaling pathways that leads to stress dependent MAPK activation.

• The Journal of Korean Society for School & Community Health Education
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• v.22 no.3
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• pp.1-15
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• 2021

Objectives: The purpose of this study was to examine whether demographic and socio-economic characteristics, health behaviors are related overweight and obesity in Korean adolescents. Methods: Data from the 15^th Korea Youth Risk Behaviors web-based Survey(KYRBWS) administered in 2019 were analyzed: 60,100 students in middle and high school participated in the survey. But except 1,555 missing value, 55,748 students were analyzed. It was conducted frequency analysis, Rao-Scott chi-square test and multiple logistic regression analysis. Results: The significant influencing factors on overweight and obesity of adolescents were gender, economic status, father's educational background, alcohol experience, fastfood consumption, muscle strengthening exercise, stress perception(p<.001). The odds ratio for overweight and obesity of male adolescents compared to female adolescents were 1.19(p<.001). and The odds ratio for overweight and obesity of perceived stress adolescents compared to those who without stress were 1.13(p<.001). Conclusions: I found that adolescents' some undesirable health behaviors affect their overweight and obesity, I recommend that school health promotion programmes should be implemented in schools to form good health behaviors such as healthy eating habits, physical exercise and managing stress.

• Nuclear Engineering and Technology
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• v.56 no.2
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• pp.688-706
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• 2024

Austenitic stainless steels (ASS) are extensively employed in various sectors such as nuclear, power, petrochemical, oil and gas because of their excellent structural strength and resistance to corrosion. SS304 and SS316 are the predominant choices for piping, pressure vessels, heat exchangers, nuclear reactor core components and support structures, but they are susceptible to stress corrosion cracking (SCC) in chloride-rich environments. Over the course of several decades, extensive research efforts have been directed towards evaluating SCC using diverse methodologies and models, albeit some uncertainties persist regarding the precise progression of cracks. This review paper focuses on the application of Acoustic Emission Technique (AET) for assessing SCC damage mechanism by monitoring the dynamic acoustic emissions or inelastic stress waves generated during the initiation and propagation of cracks. AET serves as a valuable non-destructive technique (NDT) for in-service evaluation of the structural integrity within operational conditions and early detection of critical flaws. By leveraging the time domain and time-frequency domain techniques, various Acoustic Emission (AE) parameters can be characterized and correlated with the multi-stage crack damage phenomena. Further theories of the SCC mechanisms are elucidated, with a focus on both the dissolution-based and cleavage-based damage models. Through the comprehensive insights provided here, this review stands to contribute to an enhanced understanding of SCC damage in stainless steels and the potential AET application in nuclear industry.