• 한국직업건강간호학회지
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• 제24권4호
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• pp.372-380
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• 2015

Purpose: The purpose of this study was to seek ways to improve the quality of life of workers by separating workers into the low fatigue group and the severe fatigue group depending on the level of fatigue level, and analyzing and understanding the difference between quality of life and job stress according to the fatigue level. Methods: For the 'Development of Mibyeong management system which was a consumer-directed health care service', the data of job stress, fatigue and quality of life was collected from 115 workers who visited the oriental hospitals located in J city and C city from Jul, 2012 to Dec, 2012. Results: The severe fatigue group showed significantly higher job stress than the low fatigue group in physical environment (p=.004), job demand (p<.001), interpersonal conflict (p=.012), lack of reward (p=.062). The severe fatigue group showed lower degrees both in physical component summary (PCS) (p<.001) and mental component summary (MCS) (p<.001) measured by SF-12 and the quality of life (p<.001) measured by EQ5D than the lower fatigue group. A relatively strong negative correlation was found in the item of mental component summary (MCS) measured by SF-12. Conclusion: Considering our results that high fatigue level show negative impact on quality of life and job stress, we suggest to provide a variety of health promotion strategies to improve the quality of life through the prevention and relief of fatigue for workers.

• 한국정밀공학회지
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• 제24권12호
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• pp.111-118
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• 2007

Hydroforming is a cost-effective way of shaping malleable metals such as steel into lightweight, structurally stiff and strong pieces. With the increased use of the hydroformed components in automotive and aerospace industries, it is important to know the variations of the mechanical properties in the hydroforming process far the safe and durable design purposes. The principal goal of this paper is to suggest a procedure to evaluate the variations of tensile and fatigue properties before and after a hydroforming process. A miniature specimen, which is 0.2 mm thick and 2.3 mm wide, is devised and tested to measure local mechanical properties. The effects of specimen size, defects, surface roughness, and hydroforming on the tensile and fatigue behaviors are discussed.

• 한국자동차공학회논문집
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• 제3권6호
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• pp.154-161
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• 1995

There are several kinds of driving conditions according to the characteristic of each vehicle diver. Automaker produces vehicle strong enough to satisfy this several driving conditions at the point of vehicle durability. In order to develop the car in a short period, Automaker engineer tests vehicle at serveral accelerated durability test roads. Before testing the vehicle durability, test engineer must know how much this test road severe than general field road which is composed of high way, city road, paved road and unpaved road. This paper suggests two types of road severity test method that is using relative fatigue life prediction method and using absolute fatigue life prediction method, and also present the merits and demerits of two test methods.

• 부모자녀건강학회지
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• 제21권1호
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• pp.39-49
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• 2018

Purpose: This study was to investigate the effects of fatigue, postpartum family support on postpartum depression in postpartum women. Methods: Data were collected through structured questionnaires. The participants of this study were 123 postpartum women in B metropolitan city. The data were analyzed with the SPSS/Win 18.0 program, using descriptive statistics, in independent t-test, and stepwise multiple regression. Results: The subjects' degree of fatigue and postpartum depression had strong positive correlation (r=.623, p<.001). The subjects' degree of postpartum family support and postpartum depression had moderate negative correlation (r=-415, p<.001). Factors that affect postpartum depression were fatigue (${\beta}=.492$, p<.001), postpartum family support (${\beta}=-.234$, p=.001), pre-conception job (${\beta}=.222$, p=.001), Pregnancy depression (${\beta}=.177$, p=.007), Parity (${\beta}=.167$, p=.009). The explanation power was 55.0%. Conclusion: The study results indicate that it is necessary to various programs that can reduce postpartum mothers' fatigue and improve postpartum family support, in order to reduce the postpartum depression.

• 열처리공학회지
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• 제21권3호
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• pp.131-136
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• 2008

The fatigue characteristics of the carbon fiber reinforced carbon composites (CFRC) material are necessary for the advanced industries requiring the thermal resistance. The research and development of CFRC have been in progress in the field of aerospace and defense industry. In this paper, we investigated the fatigue characteristics of CFRC by using an aircraft brake disk system. As the results of a series of tensile tests, the tensile strengths of CFRC were appeared 102.8 MPa ($0^{\circ}$), 98.6 MPa ($60^{\circ}$), and 95.5 MPa ($90^{\circ}$), respectively. It was showed that CFRC had better tensile property than the usual composite materials. As the results of fatigue tests, the fatigue limit was ~ 77 MPa, which is under the 75% of the maximum tensile load. CFRC is recommended as a strong potential composite materials because the carbon fibers are closely packed and strongly bonded between the carbon fibers.

• 대한기계학회논문집A
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• 제24권7호
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• pp.1841-1846
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• 2000

To examine the effect of acid fog on the corrosion fatigue behavior in structural steel, fatigue tests under acid fog atmosphere were carried out in comparison with distilled water. The corrosive c omponents contained in acid fog pile up the corrosion products on crack face and show a crack branching and crack tip blunting. Therefore, due to these workings crack growth rate was reduced by decreasing the effective stress range in crack tip rather than under distilled water. Also the effect of sulfuric acid, which is the main component of acid fog, and testing speed on fatigue crack growth were examined. It was found that corrosion behavior was remarkably dependent upon pH and Hz rather than components of acid fog. According as pH and testing speed decrease below a specific value, crack growth was accelerated in comparison with distilled water. This reveals that due to liquid having strong acidity and slow speed of test the crack face dissolution was promoted, so crack closure was disturbed in the process of stress descent.

• 한국컴퓨터정보학회논문지
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• 제22권6호
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• pp.115-122
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• 2017

The purpose of this study was to investigate the effects of compassion satisfaction, compassion fatigue, burnout on the attitude towards terminal care among care providers in long-term care facilities. In order to achieve the purpose of the study, data was collected from 126 care providers in long-term care facilities in Chungbuk and Kangwon province. Data were collected with self-administrated questionnaires and analyzed by hierarchical multiple regression. Findings of this study is as follows. Firstly, attitude towards terminal care was positively affected by compassion satisfaction. Secondly, the attitude towards terminal care was negatively affected by compassion fatigue. Thirdly, the attitude towards terminal care was negatively affected by burnout. In conclusion, these findings provide strong empirical evidence for the importance of compassion fatigue, compassion satisfaction and burnout in explaining attitude towards terminal care among care providers in long-term care facilities. Therefore, strategies to decrease compassion fatigue and burnout and improve compassion satisfaction are needed to improve the attitude towards terminal care among care providers in long-term care facilities.

• Safety and Health at Work
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• 제7권2호
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• pp.124-129
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• 2016

Background: Work-related fatigue has a strong impact on performance and safety but so far, no agreed upon method exists to detect and quantify it. It has been suggested that work-related fatigue cannot be quantified with just one test alone, possibly because fatigue is not a uniform construct. The purpose of this study is therefore to measure work-related fatigue with multiple tests and then to determine the underlying factorial structure. Methods: Twenty-eight employees (mean: 36.11; standard deviation 13.17) participated in five common fatigue tests, namely, posturography, heart rate variability, distributed attention, simple reaction time, and subjective fatigue before and after work. To evaluate changes from morning to afternoon, t tests were conducted. For further data analysis, the differences between afternoon and morning scores for each outcome measure and participant (${\Delta}$ scores) were submitted to factor analysis with varimax rotation and each factor with the highest-loading outcome measure was selected. The ${\Delta}$ scores from tests with single and multiple outcome measures were submitted for a further factor analysis with varimax rotation. Results: The statistical analysis of the multiple tests determine a factorial structure with three factors: The first factor is best represented by center of pressure (COP) path length, COP confidence area, and simple reaction time. The second factor is associated with root mean square of successive difference and useful field of view (UFOV). The third factor is represented by the single ${\Delta}$ score of subjective fatigue. Conclusion: Work-related fatigue is a multidimensional phenomenon that should be assessed by multiple tests. Based on data structure and practicability, we recommend carrying out further studies to assess work-related fatigue with manual reaction time and UFOV Subtest 2.

• 한국신뢰성학회지:신뢰성응용연구
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• 제13권3호
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• pp.165-174
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• 2013

Thruster break for aerogenerator performs a role that is stopping the rotor in case of emergency such as strong wind, system abnormality or maintenance check. In this study, failure analysis and test evaluation on the thruster break for aerogenerator are proposed, and the entire process to improve reliability of the product through design improvement is presented. The typical failure case is fatigue and wear, and failure cause on these are identified and improvement plan is presented. Lastly, reliability improvement is established to analyse test results before after the life test.

• Animal Bioscience
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• 제36권2호
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• pp.307-314
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• 2023

Objective: Chicken essence and branched chain amino acid (BCAA) supplementation has been recognized to significantly relieve fatigue. To obtain chicken essence with high amounts of BCAA, spent hens herein was used to prepare dripped chicken essence (SCE) and compared with commercial dripped chicken essence (CCE) for in vivo anti-fatigue effect. Methods: To determine the effect on anti-fatigue by dripped chicken essence, the exhaustive swimming was performed. Thirty-two 7-week ICR mice were divided into four groups, which included the control group (CG), CCE, SCE-1X and SCE-2X. The mice were given daily oral administration (0.012 mL/g body weight/d). The fatigue index analysis was conducted weekly. Results: The results showed that SCE had a higher BCAA level as expected, and mice treated with dripped chicken essence (CCE and SCE) could significantly improve exercise performance. The lower blood lactate level, blood urea nitrogen level and creatine phosphokinase activity were found in the supplement of SCE group compared with the CCE group, which suggested that the SCE possessed strong anti-fatigue ability. This could possibly be due to the higher content of BCAA. Conclusion: In this study, SCE promoted recovery from physical fatigue in mice and elevated endurance ability. Among them, the double dose (SCE-2X) showed the strongest anti-fatigue ability. Taken together, spent chickens could be a good source of chicken essence to improve the effect of anti-fatigue.