• Tribology and Lubricants
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• v.28 no.2
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• pp.70-80
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• 2012

Non-contact type mechanical face seals installed in mechanical systems prevent leakage of working fluid using thin working fluid film between stator and rotor. For that purpose, various kinds of surface profiles, grooves and conings have been applied on seal surfaces of stator and rotor to generate hydrodynamic and hydrostatic pressure. The thickness distribution of working fluid film is one of important factors which affect the working performances of mechanical face seal, and it is strongly affected by the surface height profiles of stator and rotor. Therefore, appropriate design of surface height profiles of stator and rotor is necessary to optimize the working performances and life of mechanical face seal. In this study, numerical analysis using finite volume method was conducted to estimate the working performances of wavy mechanical face seals which have 36 coning combinations. As results, minimum thickness of working fluid film, leakage volume of working fluid and friction torque in static equilibrium condition of mechanical face seal, and stiffness of working fluid film were obtained. The results show that the working performances of mechanical face seal were affected by the coning combinations which can change the thickness distribution of working fluid film and pressure distribution in sealing region of mechanical face seal.

• The Journal of Korean Obstetrics and Gynecology
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• v.19 no.3
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• pp.231-245
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• 2006

Purpose : To investigate and compare the characteristics of menstruation in the shift workers and the day workers, and present guidelines for health promotion of the shift-working women. Methods : Questionnaires including general health condition and QSCC II were distributed to shift-working women and day-working women in one university hospital in Gyeonggi-do and 36 questionnaires of shift-working women and 33 of day-working women were analyzed. Results : Day workers were about 5 years older than shift workers on average. There was more irregularity of menstrual cycle and period in day-working group but it is thought to incorrect because of the age problem. There were more women who have dysmenorrhea in day-working group, but the proportion of dysmenorrhea which continues more than 72 hours -which is very suggestive of secondary dysmenorrhea- was higher in shift-working group. Average VAS of dysmenorrhea was nearly the same in two groups. The life of shift-working group was lesser satisfactory than that of day-working group. There were more sleep disturbances in the shift-working group. Sasang constitution was analyzed in both group using QSCC II, and Taeumin were more in shift-working group. Conclusion : As the number of shift-working women increases, needs for oriental medical treatments would increase because it is more natural and lesser invasive managements which women are very interested in. So it is thought to be necessary to understand health problems of shift-working women, and prepare guidelines for managements and treatments to promote the health of shift-working women.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.27 no.3
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• pp.210-220
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• 2017

Objectives: This study was conducted to prepare fundamental data and prevention measures on health promotion and occupational disease, and to assess the effects of the working environment on subjective health status and absenteeism among workers using data from the third working environment survey in Korea. Methods: This study's subjects were composed of 29,711 wage workers from the 3rd working environment survey data. The dependent variables were several diseases, subjective health status and absences, and the independent variable was the working environment. The collected data were analyzed by One-Way ANOVA, Pearson's correlation and stepwise multiple analysis using the IBM SPSS(ver. 20.0) statistical package program. Results: The effecting factors for cardiovascular disease were age, working shift and emotional state. The effecting factors for anxiety and depression were years of education, working condition, duties, and emotional state. The effecting factors of insomnia were duty and emotional state. The positive effecting factors for absent days were work standing, working shift, number of night shifts, autonomy, and duties. The positive effecting factors of subjective health status were age, work standing, working years, working shift, appropriateness of working hours, leadership of superiors, duties and emotional state. Conclusions: Based on the above results, the author considers that it is necessary to improve the working environment to reduce absent days, such as by reducing of number of night shifts and giving autonomy regarding duties, and to improve the working environment for subjective health status such as by controlling the appropriateness of working hours and stability of the emotional state. In addition, this study provides fundamental data on health promotion and occupational disease among workers.

• Journal of Fashion Business
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• v.19 no.4
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• pp.37-56
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• 2015

This thesis aimed to determine the effecting factors(eating pattern, working condition, stress, health care) that help maintain the health of the cosmetologists' digestive system and the diseases involved (acid reflux, indigestion, gastritis, constipation & diarrhea). The research methods included survey and statistical analysis. The survey was conducted on 242 cosmetologists from August 30 to October 30 2014. The data analysis included frequency, cross table, ${\chi}^2$-test, and regression with SPSS(V. 14). The results were as follows ; (1) The cosmetologists' health of digestive system and eating pattern are related. Regular and enough meal times cause less digestive disease. Acid reflux, indigestion, gastritis, constipation and diarrhea are differently related with the type of usual eating pattern, especially, instant food is not good for digestive health. (2) The cosmetologists' health of digestive system and working condition are related. Longer daily working hours and exposure time to chemical odors are more likely to be associated with digestive diseases; whereas, longer time of standing and talking with colleagues are less likely to be associated with digestive diseases. (3) The cosmetologists' health of digestive system and stress are related. Headache, boredom, conflict of pay and compensation, and insomnia are not good for digestive health. (4) The cosmetologists' health of digestive system and health care are related. Periodical medical examination and usual body stretching are correlated with digestive diseases; whereas, people who do regular exercise and bowel movement are less likely to have digestive diseases.

• Wind and Structures
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• v.25 no.6
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• pp.507-535
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• 2017

In the strong wind shutdown state, the blade position significantly affects the streaming behavior and stability performance of wind turbine towers. By selecting the 3M horizontal axis wind turbine independently developed by Nanjing University of Aeronautics and Astronautics as the research object, the CFD method was adopted to simulate the flow field of the tower-blade system at eight shutdown positions within a single rotation period of blades. The effectiveness of the simulation method was validated by comparing the simulation results with standard curves. In addition, the dynamic property, aerostatic response, buckling stability and ultimate bearing capacity of the wind turbine system at different shutdown positions were calculated by using the finite element method. On this basis, the influence regularity of blade shutdown position on the wind-induced response and stability performance of wind turbine systems was derived, with the most unfavorable working conditions of wind-induced buckling failure of this type of wind turbines concluded. The research results implied that within a rotation period of the wind turbine blade, when the blade completely overlaps the tower (Working condition 1), the aerodynamic performance of the system is the poorest while the aerostatic response is relatively small. Since the influence of the structure's geometrical nonlinearity on the system wind-induced response is small, the maximum displacement only has a discrepancy of 0.04. With the blade rotating clockwise, its wind-induced stability performance presents a variation tendency of first-increase-then-decrease. Under Working condition 3, the critical instability wind speed reaches its maximum value, while the critical instability wind speed under Working condition 6 is the smallest. At the same time, the coupling effect between tower and blade leads to a reverse effect which can significantly improve the ultimate bearing capacity of the system. With the reduction of the area of tower shielded by blades, this reverse effect becomes more obvious.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.32 no.4
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• pp.287-301
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• 2022

Objectives: This study compared the characteristics of the work environment between agricultural and general workers and analyzed the effects of agricultural working characteristics on work-related health problems. Methods: The participants of this study were 2,347 agricultural workers and 48,042 general workers who were selected by applying standardized weights to the raw data of 50,538 respondents from the 6th Korean Working Condition Survey (KWCS). Variables applicable to both worker groups and related to exposure to hazardous risk factors in the working environment, working hours and intensity of work, health problems and work-related status, and satisfaction with the work environment were selected. Chi-square tests and independent sample t-tests were performed to evaluate the differences in the variables between the two groups. Multivariate logistic regression analysis was conducted to analyze the effects of work environment characteristics on work-related health problems. Results: Compared to general workers, agricultural workers were more exposed to hazardous environments, irregular work patterns such as working on Saturday/Sunday, and short repetitive tasks. They reported more work-related and general health problems, including back pain, upper extremity muscle pain, lower extremity muscle pain, and general fatigue. Agricultural workers showed lower satisfaction with their work environment than general workers. Factors affecting one or more work-related health problems included gender, working years, hazardous factors, irregular work pattern, working hours, and labor intensity. Conclusions: Our findings showed that agricultural workers were relatively more vulnerable to safety issues compared to other occupational groups. Therefore, it is necessary to establish standardized safety and health standards and strengthen systematic safety and health management policies and services for agriculture.

• Korean Journal of Rural Living Science
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• v.8 no.2
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• pp.111-117
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• 1997

In this study we tried to give a decision on propriety of working conditions, to present ideas on reducing work loads. and to grope for efficiency of agricultural works. For this we examined the actual conditions of working environment, farmer's clothes, working posture, working methods, working time, resting state, fatigue recovery methods during cultivating lettuce in the winter greenhouse. And Ive improved harmful factors that affect farmer's health by considering results of previous study and farmer's subjective sensation. And we measured, compared, and analyzed the farmer's work loads before and after improvement. The results of this study are as follows ; 1. According to examine the actual conditions of cultivating lettuce in the winter greenhouse, farmers have experienced physical and mental chronic fatigue on the basis of the hot and humid crops-centered working environment, the rough ground condition, inconsistent arrangement of working stand and sorter, heavy-weared habits. and unsuitable working posture. 2. When we improved harmful factors that affect farmer's health, conformed the positive effects on important work efficiency index such as heart rate, electromyovolume, body temperature, and microclimate inside clothing and work loads were decreased by improving the hot and humid working environment, eliminating the hillock and obstacles of working path. deliver way, arranging the working stand and sorter consistantly, decreasing the clothing weight, improving the working postures and methods as using assistant appliances, alloting the working time and sequence effectively and presenting the light gymnastic exercises and rest for fatigue restoration.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.30 no.2
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• pp.213-225
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• 2020

Objectives: In order to prepare measures to enhance construction workers' satisfaction with their working environment, the effects of working conditions and the mediating effects of safety and health information on workers' satisfaction with their working environment in the construction industry have been studied. The results of this study can be used as basic data for further studies in this field. Method: Data on 1,361 male construction workers from the 5th Korea Working Condition Survey (KWCS) were used for this study. The effects of working conditions were analyzed using SPSS 25.0 and the mediating effects of health and safety information were analyzed with SPSS PROCESS macro using the bootstrap method. Results: The safety and health management system and the self-determination of break time had a statistically significant positive effect on satisfaction with the working environment. Chemical and ergonomic risk factors had a statistically significant negative effect on satisfaction with the working environment. The provision of safety and health information, the mediating variable, had a statistically significant positive effect on satisfaction with the working environment. Therefore, it had a mediating effect between working conditions and satisfaction with the working environment. Conclusion: In order to enhance construction workers' satisfaction with their working environment, the above results suggest that the safety and health management system should be well established; self-determination of break times should be guaranteed; and chemical and ergonomic risk factors should be controlled. In addition, workers should be provided with necessary health and safety information related to their work. This study will be useful if these findings are used as basic data in further studies in related fields.

• Journal of radiological science and technology
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• v.9 no.1
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• pp.51-63
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• 1986

We got the following results from the 324 radiologic technologists as we surveyed their working condition by using the questionaire, who were working in the medical institutions (general hospitals and doctor's clinics) situated in the area of Seoul city, Kyung ki-do and Chung-chong-do since June to December 1985. 1. Their daily average working time was almost within 10 hours (in 93.9% of general hospitals, 66.1% of clinics). 2. About the numbers of holidays, 85.5% of general hospitals have one holiday per week,41.3% of clinics have one holiday per week or 38.5% of clinics have one holiday per two weeks. 3. Duty appointment of radiologic technologists in the department of radiology is taking charge of each part after serving for a certain part for some period (42.8%), taking charge of the special part continually or by turns in other working parts (35.3%). On the other hand in the clinics they took charge of all parts continually (53.2%) or by turns with their own situations. (30.3%). 4. Their daily working amount is too much in 51.6% of general hospitals or 45.8% of clinics. 5. They answered it was hard in 81.4% of general hospitals or 43.1% of clinics about the degree of difficulty of their work. 6. Their monthly salary is higher in the clinics than in the general hospitals and higher in Seoul area than in Kyung-ki or Chung-chong area. 7. Their yearly bonus .ate is 400%-600% (69.2%) in almost general hospitals, 100%-300% (57.8%) in th. clinics. 8. Danger allowance is paid with the monthly salary in 62.8% of the general hospitals or 19.2% of clinics and license allowance is paid in 44.7% of general hospitals or in 12.8% of clinics. 9. Their initial salary (except bonus) is about 200,000 won (in 76.8% of general hospitals, in 67.8% of clinics). 10. Their salary is raised regulary every year in 52.6% of general hospitals, but it is irregulary in 73.4% of clinics. 11. Promotion system is managed in 48.4% of the general hospitals or in 14.7% of clinics. 12. Retirement allowance is assured in 96.9% of the general hospitals or in 63.3% of clinics. 13. Main cause of their retirement is moving to more paid hospitals, better hospitals in working condition or facilities, moving to another cities, to the hospitals with more opportunities of promotion or choosing other jobs etc. 14. Human relationship with doctors, nurses or co-worker technologists as a member of medical team appeared almost intimate and good.

• Safety and Health at Work
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• v.15 no.1
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• pp.73-79
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• 2024

Background: This study aimed to investigate the relationship between work-related communication devices use during work outside of regular working hours and depressive symptoms in wage workers. Methods: Data from 50,538 workers aged 15 years or older who had participated in the 6th Korean Working Condition Survey (KWCS) were used. The final sample was 32,994 wage workers. The questionnaire asked the respondents how often they used communication devices for work during work outside of regular working hours. Depressive symptoms were assessed using WHO-5 Well-Being Index. Multiple logistic regression analysis was used to analyze the association between work-related communication devices use during work outside of regular working hours and depressive symptoms. Results: The rate of depressive symptoms was highest among workers who did not use work-related communication devices during work outside of regular working hours. After adjusting for socio-demographic and work-related factors, the odds ratio of depressive symptoms among workers who used communication devices when working outside of regular working hours was 1.20 (95% CI: 1.09-1.32); the odds ratio of depressive symptoms in the group not using communication devices for free-time work was 1.66 (95% CI: 1.37-2.00), which was higher than that of the reference group, that is, workers who did not work outside of regular working hours, and was statistically significant. Conclusion: Regardless of whether work-related communication devices are used, working outside of regular working hours increases depressive symptoms. The use of work-related communication devices during work outside of regular working hours can reduce the rate of depressive symptoms.