• Steel and Composite Structures
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• 제1권2호
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• pp.231-244
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• 2001

The strengthening of reinforced concrete structures using externally bonded steel or advanced fibre reinforced plastic (FRP) composites is becoming increasingly common. A key factor affecting the behaviour and reliability of such strengthened structures is the bond strength between the steel or FRP plate and the concrete substrate. Several different experimental set-ups have previously been used to determine bond strength. This paper presents a careful finite element analysis of the stress distributions in these test set-ups. Results show that stress distributions can be significantly different for different set-ups, for similar materials and geometry.

• Advances in nano research
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• 제15권4호
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• pp.285-294
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• 2023

This study is aimed to investigate the electrically conductive properties of epoxy nanocomposites exposed to an acidic environment under various mechanical loads. For simultaneous assessment of the acidic environment and mechanical load on the electrical conductivity of the samples, the samples with and without carbon nanotubes were exposed to the acidic environment under three different loading conditions for 20 days. Then, the aged samples' strength and flexural stiffness degradation under crude oil and bending stress were measured using a three-point flexural test. The aged samples in the acidic environment and under 80 percent of their intact ultimate strength revealed a 9% and 26% reduction of their electrical conductivity for samples with and without CNTs, respectively. The presence of nanoparticles declined flexural stiffness by about 16.39%. Scanning electron microscopy (SEM) images of the specimen were used to evaluate the dispersion quality of CNTs. The results of this study can be exploited in constructing conductive composite electrodes to be used in petroleum environments such as crude oil electrostatic tanks.

• 치위생과학회지
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• 제15권4호
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• pp.472-479
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• 2015

치과위생사의 주요 건강문제인 근골격계 장애를 조사하고, 근무환경 요인과 스트레스 및 근골격계 장애의 관련성을 파악하기 위해 광주지역 치과위생사 483명을 편의 추출하여 자기기입식 설문조사를 시행하고 빈도분석, 교차분석, t-검정, 다중 로지스틱 회귀분석을 실시하여 분석한 결과는 다음과 같다. 연구대상자의 심한 통증을 호소하는 정도인 근골격계 장애는 29.8%였다. 근무환경요인과 스트레스 및 근골격계 장애의 관련성을 파악한 결과, 근무환경 요인에서 휴식시간 빈도였으며, 그 외 스트레스 요인 등이었다. 근무환경 요인에서 휴식시간 빈도가 없음으로 응답한 군에 비해 2회라고 응답한 군의 OR은 0.29 (95% CI, 0.11~0.73)로 근골격계 장애가 감소하여 유의한 차이를 보였으나, 휴식시간 빈도가 1회와 3회 이상에서는 유의한 차이가 없었다. 스트레스의 근골격계 장애 OR은 0.44 (95% CI, 0.27~0.70)로 음의 상관관계를 보였다. 이것은 휴식시간 빈도가 적당할수록(2회일 때) 근골격계 장애가 낮음을 의미하며, 근골격계 장애가 있는 경우 스트레스가 낮게 나타났다.

• 보건교육건강증진학회지
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• 제19권3호
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• pp.107-120
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• 2002

There has been a rapid industrial progress in Korea since 1962 by the success of 5-year economic development plan, and the number of industrial work has also made a rapid increase. Consequently, the management of the occupational health for the purpose of promoting the health of industrial workers and improving the working environment is badly needed in these days. Health services on industrial noisy environment have been provided only for noise-induced hearing loss management until now. But gradually, modem diseases and death have come to be related to the stress and mental health, therefore noise-induced mental disorder, like a stress became very important. Thus, this study has been carried out to analyze the relationship between workers' stress symptoms and the perceived working environment and the perceived working conditions. This study included 786 industrial workers selected from II factories in Buchun. The results were as follows: 1. For demographic characteristics, most of the workers were males(75.7%), the 20～29 years old were 33.8% and those who graduated from high school were 56.1%. The workers whose monthly income ranged from 700,000 to 1,500,000 won were 37.9% and who has a religion were 49.0%. 2. For occupational characteristics, workers who had worked 5～10 years in the factories were 35.8%. Those who felt much for them workload were 42.7% and who worked more than 8 hours a day were 73.7%. Those who were dissatisfied with their pay and job were 51.1 % and 31.2%. The workers who responded ventilation condition of their worksites were bad were 50.4% and the dissatisfied with working environment of their worksites were 43.8%. 3. For the noise exposure level in worksite, workers who were exposed to 70∼90㏈ were 37.4%, 90∼100㏈ were 25.2% and 50∼70㏈ were 18.8%. 4. Workers∼ stress symptoms were significantly related to marital status and their monthly income(P〈0.05). Workers who were single and had lower monthly income showed higher PSI(Psychiatric Symptom Index) scores than those who were married and had higher monthly income. Higher PSI scores were also significantly related to the night-work, workload, dissatisfaction with their job, and bad relationship with their bosses or co-workers. 5. The higher noise exposure level in worksite from 80㏈ was, the more severe stress symptoms including PSI subparts were reported; Anxiety, Anger, Depression, and Cognitive disorder symptom(P〈0.001). 6. According to the results of stepwise multiple regression analysis, factors affecting workers' PSI scores were noise exposure level in worksite(R2=0.150), relationship with coworkers, amount of workload, monthly income and relationship with bosses orderly and the total R2 of this 6 factors was 29.7%.

• 한국동물학회지
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• 제7권1호
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• pp.23-28
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• 1964

120 mice of both sexes weighing from 18 to 22 g. were used. These mice were divided nito 12 groups : control (non-restraint and restraint) , acclinmation (non-restraint and restraint , acclimation for 5 and 10 days) , adrenalectomized (non-restraint and restraint0 and acclimation-adrenalectomized (non-restraint and restraint, acclimation for 5 and 10 days) groups. The rectal temperature of each group were measured at 10, 30 and 50 min under environment of $0^{\circ}C$.Measurements were done with a microphrometer of B.T.-32 thermocorpules. The results obtained may be summarized as follows : 1) The rectal temperature in normal mice without restraint was higher than that of normal mice with restraint under environment of $0^{\circ}C$. 2) The rectal temperature in normal mice was higher than that of adrenalectomized mice at 20$^{\circ}$ C. But the rectal temperature in adrenalectomized mice without restraint was higher than that of adrenalectomized mice with restraint under cold-stress. This difference was in the order of 1.65$^{\circ}$ under environment of 20$^{\circ}$ and 10 $^{\circ}$ at 50 min under environment of 0$^{\circ}$. 3) The rectal temperature of normal mice with restraint was less than that of adrenalectomized mice (non-restraint) under cold-stress. 4) The rectal temperature of normal and adrenalectomized mice that acclimated under cold stress ($0^{\circ}C$) for 5 and 10 days was usually higher than that of normal and adrenalectomized mice of non-acclimation under environment of $0^{\circ}C$. 5) The tolerance in mice under cold-stress was increased on the acclimtion of cold.

• 간호행정학회지
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• 제15권3호
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• pp.463-470
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• 2009

Purpose: The purpose of this study was to examine the level of occupational stress and depression in clinical nurses and to investigate the effects of subscales of occupational stress on depression. Method: A sample consisted of 202 nurses from 6 hospitals located in Busan and GyeongNam province. The data were collected from November 2008 to march 2009. A self-administered questionnaire was used to assess socio-demographics, job characteristics, depression measured by Korean CES-D, and occupational stress assessed by KOSS. Result: The total score of occupational stress in clinical nurses was within bottom 25%, but the scores of 'Difficult physical environment', 'High job demand', 'Inadequate social support', 'Organizational injustice' were within top 50%. The 8 subscales of occupational stress had significantly effects on clinical nurses' depression after controlling for age, marital status, type of hospital, current position. Conclusion: The administration of employee assistance program for management occupational stress is important for decreasing depression in clinical nurses.

• 산업경영시스템학회지
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• 제31권4호
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• pp.41-48
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• 2008

The purpose of this study was to investigate the job stress factors that were related to the general characteristics, work characteristics, and health characteristics of the workers at distribution industry. The survey of job stress measurement scale for Korean employee which was developed by KOSHA and OSHRI in 2003 was used for this study. Three hundred and fifty workers at distribution industry participated in this study, and among them 326 responses were analyzed for this study due to the unreliability and insincerity of responses. Eight job stress factors like physical environment, self-control for the job, job unsecure, organization system, workplace culture, compensation for the job, relationship to the superior, and job requirement were analyzed. The results showed that the stress because of self control for the job was relatively higher than that of other industry workers. However, the stress because of physical environment, job requirement, job unsecure, organization system and compensation for the job was relatively lower than that of other industry workers. The female workers felt more stress than male workers in compensation for the job and workplace culture factors at distribution industry. The delivery and carrying job workers were more stressful than those of other jobs at distribution industry because of physical environments and self-control for the job. The non-regular job workers were more stressful than regular job workers in many stress factors like self-control for the job, job unsecure, organization system and compensation for the job.

• 인간식물환경학회지
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• 제24권2호
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• pp.137-152
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• 2021

Background and objective: This study was carried out to investigate and analyze the preference for plant fragrance and the psychological effects of a agro-healing activity in 101 firefighters aged 39.71 ± 10.94. Methods: For the psychological evaluation, post-traumatic stress symptoms, Korean occupational stress scale short form (KOSS-SF), emotional intelligence, and job satisfaction were surveyed on the Likert scale. For the preference for plant fragrances, 20 ㎕ of commercially available essential oils from four plant species (Mentha spp., Lavandula spp., Citrus limon, C. sinensis) were absorbed into each test paper and provided to the participants. Results: The rate of post-traumatic stress symptoms was high at 37.6% of the firefighters surveyed.. C. limon fragrance had the highest preference among the four plant fragrances, followed by C. sinensis > Mentha spp. > Lavandula spp. with statistically significant difference (F = 14.256, p < .001). The lower their age, income, and position, and higher the education level, the higher the preference for plant fragrances. And the administrative group had higher preference for plant fragrances than field group. In addition, as a result of examining the correlation between job satisfaction, preference for plant fragrance, post-traumatic stress, emotional intelligence, and job stress for fire-fighters, the higher the job satisfaction, the higher the fragrance preference and emotional intelligence, and the lower the post-traumatic stress and job stress. Conclusion: Therefore, installing a garden using botanical fragrances at workplaces that firefighters can easily access will improve job satisfaction and relieve stress. It can be concluded that applying the fragrance of plants to the healing farming activities at the fire-fighter's workplace can increase the usefulness of the healing activities.

• 한국치위생학회지
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• 제11권6호
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• pp.913-922
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• 2011

Objectives : This study aims to analyze the factors and degree of stress, which dental hygienics students experience during the off-campus practical training period at university/general dental hospitals or dental hospitals/clinics, to strategically plan and operate an efficient practical training, and to exploit such data for development of the said students into professional dental hygienists by nurturing their abilities to effectively cope with the potential educational frustration, demotivation, and skepticism on their occupations in advance. Methods : The stress measurement tool is set for 38 questions in total, The grading system for each question is based on 5-point Likert scale, which interprets that the lower score demonstrates a higher level of stress. The data collected as above are analyzed by SPSS 19.0. Results : The satisfaction "Satisfactory" of extramural practice at departments of dentistry of university and general hospitals and dental hospitals and clinics is 48.3% and 37.7% respectively. Environment area (p<.001) and role & activity area (p<.05) showed a significant difference of stresses between practices at departments of dentistry of university and general hospitals and dental hospitals and clinics. For departments of dentistry of university and general hospitals, the stress in environment area was highest. On the contrary, students who did practices at dental hospitals and clinics showed that the stress is highest at role & activity area. There was a positive correlation of areas of environment, personal relations, role & activity, and ideal & value. However, there was no correlation between treatment fields. Conclusions : In conclusion, educational institutes need to conduct a specialized systematic research establishing close relationships extramural practice organs, in order to minimize students' stress resulting from extramural practices by type and to increase the effect of extramural practices.

• Animal cells and systems
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• 제15권3호
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• pp.219-225
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• 2011

We studied oxidative stress in cinnamon clownfish exposed to hypoosmotic (35 psu ${\rightarrow}$ 17.5 psu and 17.5 psu with prolactin (PRL)) and low temperature ($28^{\circ}C{\rightarrow}24^{\circ}C$ and $20^{\circ}C$) conditions by measuring the expression and activity of Cu/Zn-superoxide dismutase (Cu/Zn-SOD), catalase (CAT), and glutathione peroxidase (GPX). The expression and activity of the antioxidant enzymes were significantly higher after the fish were exposed to $24^{\circ}C$, $20^{\circ}C$, and 17.5 psu, and expression was repressed by PRL treatment. Furthermore, we measured $H_2O_2$ and lipid peroxidation levels and found that they were significantly higher after exposure to the hypoosmotic and low-temperature environments. Additionally, we investigated changes in plasma AST and ALT levels after exposure to low temperature and hypoosmotic stress. These levels increased upon exposure of the clownfish to $24^{\circ}C$, $20^{\circ}C$, and 17.5 psu, but the levels of these parameters decreased in the 17.5 psu with PRL treatment during a salinity change. The results indicate that hypoosmotic and low-temperature conditions induce oxidative stress in cinnamon clownfish and that the parameters tested in this study may be indices of oxidative stress in the cinnamon clownfish.