• Title/Summary/Keyword: Variable stress

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Approximate residual stress and plastic strain profiles for laser-peened alloy 600 surfaces

  • Eui-Kyun Park ;Hyun-Jae Lee ;Ju-Hee Kim ;Yun-Jae Kim
    • Nuclear Engineering and Technology
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    • v.55 no.4
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    • pp.1250-1264
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    • 2023
  • This paper presents approximate in-depth residual stress and plastic strain profiles for laser-peened alloy 600 surface via FE analysis. In approximations, effects of the initial welding residual stress and the number of shots are quantified. Based on FE analysis results, residual stress profiles are quantified by two variables; the maximum difference in stress before and after LSP, and the depth up to which the compressive residual stress exists. Plastic strain profiles are quantified by one variable, the maximum equivalent plastic strain at the surface. The proposed profiles are validated by comparing with published LSP experimental results for welded plates. Effects of the initial welding residual stress and the number of shots on these variables are discussed. The proposed profile can be directly applied to predict the mitigation effect of LSP on PWSCC and to efficiently perform structural integrity assessment of laser peened nuclear components.

The Influence of Sociocultural Attitude toward Appearance and Narcissism on Body Stress

  • Park, Eunhee;Lee, Sangjoo
    • Journal of Fashion Business
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    • v.18 no.6
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    • pp.1-18
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    • 2014
  • The purpose of this study is to examine the influence of sociocultural attitudes toward appearance and narcissism on body stress. Questionnaires are being administered to 206 women in their 20's-50's living in Deagu and Kyunbook province. The Frequency, factor analysis, reliability analysis, correlation analysis, regression analysis, ANOVA, and Duncan-test are used for data analysis. Sociocultural attitudes toward appearance are categorized into media appearance internalization and social recognition of appearance. Narcissism factors are found to be leadership/privilege, ostentation, and superiority. Body stress is categorized into 4 factors: weight stress, skin aging stress, body dissatisfaction, and hair stress. Sociocultural attitudes toward appearance was related to the sub-variables of narcissism, and body stress. Media appearance internalization is the sun-variable of sociocultural attitudes toward appearance and has significant effects on weight stress, skin aging stress, and body dissatisfaction sub-variables for body stress. Ostentation, and superiority being the sub-variables of narcissism, have significant effects on weight stress, skin aging stress, body dissatisfaction, and hair stress, the sub-variables for body stress. Ages of women display distinctions between the sub-variables in sociocultural attitudes toward appearance such media appearance internalization, and in narcissism such leadership/privilege, ostentation, superiority, and body stress such weight stress, skin aging stress, body dissatisfaction, and hair stress. This result can be a necessary base line data for adult women's appearance management by examining the influence of the attitude toward the appearance developed from the relationship with people around body stress.

Development of 3D MLS-based variable-node elements for easy meshing (요소망 구성이 편리한 3 차원 MLS 기반 변절점요소 개발)

  • Cho, Young-Sam;Park, Jong-Youn
    • Proceedings of the KSME Conference
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    • 2008.11a
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    • pp.1633-1637
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    • 2008
  • In this study, we developed 3D MLS-based variable-node elements for easy meshing. These elements should be derived from 2D MLS-based variable-node elements and would be utilized as key elements of easy meshing technique we proposed. Using developed 3D MLS-based variable-node elements, we demonstrated several examples having complex configuration compared with conventional meshing technique. Moreover, we compared with the stress results of our model and conventional one.

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The Effect of Stress Ratio on Fatigue Crack Propagation Rate and Arrest Behavior in 7075-T735 Al Alloy (7075-T735 Al 합금의 피로균열 진전속도와 정류거동에 미치는 응력비의 영향)

  • 오세욱;강상훈;허정원;김태형
    • Journal of Ocean Engineering and Technology
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    • v.6 no.1
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    • pp.131-139
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    • 1992
  • The understanding and appllication of fatigue crack propagation mechanism in variable amplitude loading is very important for life prediction of the air travel structures. Particularly, the retardation and arrest behavior of fatigue crack propagation by single tension overloading is essential to the understanding and appllication of fatigue crack propagation mechanism in variable amplitude loading. Numerous studies of the retardation behavior have been performed, however investigations of the arrest behavior have not been enough yet. As for the arrest behavior, Willenborg had reported that the overload shut-off ratio $[R_{so}=(K_{OL})/K_{max})_{crack arrest}]$ had been the material constant, but recently several investigators have reported that the overload shut-off ratio depends upon the stress ratio. In this study, authors have investigated the effect of stress ratio on the threshold overload shut-off ratio to generate arrest of fatigue crack growth in high tensile aluminum alloy 7075-T735 which have used in material for air travel structures, It has been $-0.4\leqqR\leqq0.4$ till now, the region of stress ratio investigated. The threshold overload shut-off ratio has decreased as stress ratio has increased in overall region of -$-0.4\leqqR\leqq0.4$ and the linearity has been seen in this material. Moreover, the experimental equation between $R_{so}$ and R has been made; The relation has been $R_{so}=-R+2.6$.

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Stress and Experience of Doing Harm: Moderating Effects of Human Rights Consciousness (아동청소년의 스트레스와 차별가해경험: 인권의식의 조절효과)

  • Oh, Mi-Ok;Lee, Jin-Hyang
    • The Journal of the Korea Contents Association
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    • v.18 no.8
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    • pp.494-502
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    • 2018
  • The main objectives of this study are to examine the effects of stress on the experience of doing harm of the children and adolescents and to examine the moderating effect of human rights consciousness on the relationship between the stress and the experience of doing harm. To do this, we analyzed the data obtained from Survey on Human Rights of Children and Adolescents in 2015. The subject is 10,424 from the 4th grade of elementary school to the 3th grade of high school. To investigate the moderating effects of variable, we have conducted a hierarchical regression analysis and confirmed changes in explanatory power. As a result of that, first, it suggests that stress and human rights consciousness have direct effects on the experience of doing harm. This results show that the lower stress and the higher human rights consciousness is, the lower experience of doing harm is. Second, it was found that human rights consciousness is moderating variable on the relationship of between the stress and the experience of doing harm. Based on this results, this study has proposed the implications and limitations of it and suggestions for further study.

Chronic Administration of Monosodium Glutamate under Chronic Variable Stress Impaired Hypothalamic-Pituitary-Adrenal Axis Function in Rats

  • Seo, Hee-Jeong;Ham, Hyang-Do;Jin, Hyung-Yong;Lee, Woo-Hyung;Hwang, Hyun-Sub;Park, Soon-Ah;Kim, Yong-Sung;Choi, Suck-Chei;Lee, Seoul;Oh, Kyung-Jae;Kim, Byung-Sook;Park, Byung-Rim;Lee, Moon-Young
    • The Korean Journal of Physiology and Pharmacology
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    • v.14 no.4
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    • pp.213-221
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    • 2010
  • The hypothalamic-pituitary-adrenal (HPA) axis is the primary endocrine system to respond to stress. The HPA axis may be affected by increased level of corticotrophin-releasing factors under chronic stress and by chronic administration of monosodium glutamate (MSG). The purpose of this study was to investigate whether chronic MSG administration aggravates chronic variable stress (CVS)-induced behavioral and hormonal changes. Twenty-four adult male Sprague-Dawley rats, weighing 200~220 g, were divided into 4 groups as follows: water administration (CON), MSG (3 g/kg) administration (MSG), CVS, and CVS with MSG (3 g/kg) administration (CVS+MSG). In addition, for the purpose of comparing the effect on plasma corticosterone levels between chronic stress and daily care or acute stress, 2 groups were added at the end of the experiment; the 2 new groups were as follows: naive mice (n=7) and mice exposed to restraint stress for 2 h just before decapitation (A-Str, n=7). In an open field test performed after the experiment, the CVS+MSG group significant decrease in activity. The increase in relative adrenal weights in the CVS and CVS+MSG group was significantly greater than those in the CON and/or MSG groups. In spite of the increase in the relative adrenal weight, there was a significant decrease in the plasma corticosterone levels in the CVS+MSG group as compared to all other groups, except the naive group. These results suggest that impaired HPA axis function as well as the decrease in the behavioral activity in adult rats can be induced by chronic MSG administration under CVS rather than CVS alone.

A study on the psychological well-being of the parents of the adult intellectual disabilities - on the fucus of gender differences. (성인 지적장애인 아버지와 어머니의 심리적 안녕감 설명모형 연구)

  • Yoo, Yong-Shik;Roh, Seung-Hyun
    • Korean Journal of Social Welfare Studies
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    • v.41 no.4
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    • pp.247-276
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    • 2010
  • This study aimed to examine the model to explain the mediator effect of care evaluation(care stress, care satisfaction) on the effect of stress factors and resource on the psychological well-being of the parents of the adult intellectual disabilities. Examining whether there is a difference between the gender of parents was another aim of this study. Study results showed that with the care stress as an endogenous variable, the daily life function and maladjustment behavior of adult children and the health state of parents had a significant direct effect on the psychological well-being of parents. With care satisfaction as an endogenous variable, family support, expert support and care stress had a significant direct effect. With the psychological well-being as an endogenous variable, care satisfaction and care stress had a significant effect, but the health state of parents didn't. In case of indirect effect, the care stress had a significant mediator effect on the effect of the physical function and maladjustment behavior of adult children and the health state of parents on the psychological well-being of parents. Care satisfaction had a significant mediator effect on the effect of family support, expert support and care stress on the psychological well-being of parents. According to the result of the Multiple Group Analysis, the path showed a statistically significant difference between gender was friend support→care satisfaction, care stress→psychological wellbeing, expert support→care satisfaction. On the basis of the study results, practical suggestions were made.

The Levels of Psychosocial Stress, Job Stress and Related Factors of Medical Doctors Practicing at Local Clinics (일부 개원의사들의 사회심리적 스트레스 및 직무 스트레스 관련 요인)

  • Kang, Moon-Kuk;Kim, Jang-Rak;Jeong, Baek-Geun;Park, Ki-Soo;Kam, Sin;Hong, Dae-Yong;Kang, Yune-Sik
    • Journal of Preventive Medicine and Public Health
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    • v.40 no.2
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    • pp.177-184
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    • 2007
  • Objectives : This study was conducted to investigate the levels of psychosocial stress, job stress and their related factors among medical doctors practicing at local clinics. Methods : A survey using a self administered questionnaire was administered to 1,456 doctors practicing at private clinics via post for 2 months (2006. 1 - 2006. 3). Psychosocial stress, job stress, demographic factors, job related factors and health related behaviors were investigated. Among the eligible study population, the respondents were 428 doctors (29.4%). Results : The average scores of psychosocial stress and job stress were 2.19 and 3.13, respectively. The levels of psychosocial stress and job stress were statistically lower in older respondents, those who worked shorter or who were more satisfied with their job, and those with higher socioeconomic status. The level of psychosocial stress was related with smoking status, drinking status and exercise. The level of job stress was related with smoking status and exercise. In multiple linear regression analysis using psychosocial stress as a dependent variable, age, working hours per day, job satisfaction and perception on socioeconomic status were significant independent variables. In analysis using job stress as a dependent variable, age, working hours per day and job satisfaction were significant independent variables. Conclusions : Stress affects the doctor-patient relationship, productivity and overall health level of people. Therefore, it is important to manage and relieve the stress of doctors. It is suggested that more advanced studies on stress level and related factors and ways to improve the stress and health related behaviors of medical doctors should be conducted.

Analysis of the Relationship between Macpa Stress Index and Korean Job Stress Level - Focusing on Subway Construction Workers (맥파 스트레스와 한국인 직무스트레스의 상관관계 분석 - 도시철도 건설종사자를 대상으로)

  • Chae, Joung Sik;Lee, Yu Jeong;Chang, Seong Rok
    • Journal of the Korean Society of Safety
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    • v.37 no.1
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    • pp.64-69
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    • 2022
  • The study measured a subway construction worker's Macpa stress by Heart Rate Variability measuring instrument and conducted a survey of Korean job stress from subway construction workers. Also, the study analyzed the relationship between Macpa stress index and Korean job stress result and suggested managing stress method for each item. According to National Statistical Office data, the first line subway in Seoul was started to open in 1974. The extended total length is 996 kilometers until 2019. Many aged workers are currently working at subway construction sites due to the avoidance of young workers since the past until now. It means that the elderly has a substantial portion among subway construction workers. The productivity has been adversely affected by health problems due to the aging of workers, job stress due to heavy work, and personal health problems. So, the regulation and policies on job stress health management are being strengthened. The data were measured Macpa stress by machine measuring heart rate variability and conducted Korean job stress survey(shortened) from Sa-sang to Ha-dan line Busan subway construction workers for analyzing the relationship. Independent variable were age, job duration, job position, employment type, working type in this study. Macpa's dependent variable was stress index and Korean job stress survey(shortened)'s dependent variables were job requirements, job autonomy, relationship conflict, job instability, organizational structure, inappropriate compensation, working place culture, and total score. SPSS 12.0 K Statistics Program was used for statistical analysis. Kruskal-wallis test, a nonparametric statistical analysis, was used because the data are difficult to be assumed as normal distribution. As a result, the paper indicated the significant correlation between Macpa stress index and Korean job stress(short version). The elderly workers presented higher Macpa index and higher job stress due to aging and heavy-duty work. The majority workers were daily workers who had unstable working condition and uncertainty about the future. The study suggested a manual that could reduce job stress for subway construction workers and future study deriving management tool through analyzing job stress factor is necessary.

The effects of adolescents' demographic variables, stress, and appearance management behavior on their self-esteem (청소년의 인구통계적 특성 및 스트레스, 외모관리행동이 자아존중감에 미치는 영향)

  • Ha, Kyungyun;Kang, Ineon
    • Journal of Fashion Business
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    • v.16 no.5
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    • pp.192-206
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    • 2012
  • This study aimed to examine the effects of demographic variables, stress, appearance management behavior, and family environment on self-esteem with the subjects of high school students with serious stress and great interest in appearance among the adolescences. This research was conducted during June, 2012, and the research method employed was the questionnaire. The questionnaire consisted of the contents about self-esteem, stress, appearance management behavior, and demographical variables. Regarding the adolescents' stress, generally, influential variables include relationship with parents and friends, school records, or school life satisfaction. And the adolescences' self-esteem was the crucial variable to indicated socio-psychological adaptation. And it was related with stress or appearance management behavior.