• Toxicological Research
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• v.32 no.4
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• pp.327-335
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• 2016

This study aimed to evaluate the potential toxicity and safety of ethyl hydrogen adipate (EHA) by determining its effect on the reproductive function and development of Sprague-Dawley (SD) rats at dose levels of 0 (control), 200, 400, and 800 mg/kg/day. One male and five females of the 800 mg/kg/day died. Body weight loss was observed in the males of the 800 mg/kg/day and in females of the 400 and 800 mg/kg/day. In addition, mating indices decreased and pre-implantation loss rates increased in parental animals of the 400 and 800 mg/kg/day. The gestation index decreased in the male and female rats of the 800 mg/kg/day. Moreover, the body weight of the pups from the 800 mg/kg/day group decreased on post-parturition day 4. These results indicated that the no-observed-adverse-effect level of EHA for parental males and females was 400 mg/kg/day and 200 mg/kg/day, respectively, and that for pups was 400 mg/kg/day.

• Korean Chemical Engineering Research
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• v.54 no.3
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• pp.367-373
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• 2016

Many of plastic powders handled in industry are combustible and have the hazard of dust fire and explosion accidents. However poor information about the safe handling has been presented in the production works. The aim of this research is investigated experimentally on explosive characteristics of various plastic powders used in industry and to provide additional data with safety informations. The explosibility parameters investigated using standard dust explosibility test equipment of Siwek 20-L explosion chamber. As the results, the dust explosion index ($K_{st}$) of ABS ($209.8{\mu}m$), PE ($81.8{\mu}m$), PBT ($21.3{\mu}m$), MBS ($26.7{\mu}m$) and PMMA ($14.3{\mu}m$) are 62.4, 59.4, 70.3, 303 and 203.6[$bar{\cdot}m/s$], respectively. And flame propagation velocity during plastic dust explosions for prediction of explosive damage was estimated using a flame propagation model based on the time to peak pressure and flame arrival time in dust explosion pressure assuming the constant burning velocity.

• Smart Structures and Systems
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• v.29 no.2
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• pp.361-374
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• 2022

As civil infrastructure has continued to age worldwide, its structural integrity has been threatened owing to material deteriorations and continual loadings from the external environment. Structural Health Monitoring (SHM) has emerged as a cost-efficient method for ensuring structural safety and durability. As SHM research has gradually addressed an increasing number of structure-related problems, it has become difficult to understand the changing research topic trends. Although previous review papers have analyzed research trends on specific SHM topics, these studies have faced challenges in providing (1) consistent insights regarding macroscopic SHM research trends, (2) empirical evidence for research topic changes in overall SHM fields, and (3) methodological validations for the insights. To overcome these challenges, this study proposes a framework tailored to capturing the trends of research topics in SHM through a bibliometric and network analysis. The framework is applied to track SHM research topics over 15 years by identifying both quantitative and relational changes in the author keywords provided from representative SHM journals. The results of this study confirm that overall SHM research has become diversified and multi-disciplinary. Especially, the rapidly growing research topics are tightly related to applying machine learning and computer vision techniques to solve SHM-related issues. In addition, the research topic network indicates that damage detection and vibration control have been both steadily and actively studied in SHM research.

• Toxicological Research
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• v.17
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• pp.25-35
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• 2001

In 1990, Tolerable Daily Intake (TDI) of 10 pg TCDD/kg/day for dioxins based on carcinogenicity and reproductive toxicity was determined by WHO/EURO, that resulted in the establishment of TDIs in other countries. In Japan, Ministry of Health and Welfare and Environment Agency, respectively established the TDI of 10 pg TCDD/kg/day and Health Risk Assessment Index of 5 pg TCDD/kg/day in 1996. Accumulation of new scientific data, especially by molecular toxicology since 1990, resulted in the reevaluation of TDI by WHO-ECEH and IPCS in May, 1998. At this meeting, it was stressed that \circled1 toxic effects of dioxin is mediated through Ah-receptor in both animals and humans, \circled2 use of ebody burdeni concept is better than the use of traditional NOAEL/UF approach, \circled3 inclusion of coplanar PCBs in the TDI by the use of new WHO-TEF. LOAELs (0.16~200 ng TCDD/kg/day) obtained from reproductive toxicity and immunotoxicity in rats, and neurobehavioral toxicity and induction of endometriosis in rhesus monkeys are calculated to be the body burden of 10~50 ng TCDD/kg that is 14~37 pg TEQ/kg/day as human daily intake. Finally TDI of 1~4 pg TEQ/kg/day was established by applying the UF of 10. In Japan, reproductive toxicity and immunotoxicity in rats were used to obtain LOAELs (100~200 ng TCDD/kg/day). Finally TDI of 4 pg TEQ/kg/day was established in June 1999 by applying the UF of 10 to human daily intake of 43.6 pg TEQ/kg/day which corresponds to the body burden of 86 ng TCDD/kg.

• Korean Journal of Occupational Health Nursing
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• v.26 no.3
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• pp.160-171
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• 2017

Purpose: This review aimed to integrate the results of studies related to presenteeism in clinical nurses and to suggest directions for future research. Methods: The search for relevant studies was conducted using six data bases according to predetermined index terms, "$nurs^*$" and "presenteeism." Thirteen studies that met the inclusion criteria were selected and analyzed. Results: This review found that the conceptual use and scope of presenteeism were not consistent among the studies. Most studies investigated the nurses' health-related variables as the most important factors and reported their positive association with presenteeism. Presenteeism was also found to be associated with job stress, job satisfaction, social support, and organizational culture and had a negative impact on nursing outcomes such as patient safety. Conclusion: The research on presenteeism can be used as a way to explain outcomes in the field of nursing where direct measurement of productivity is difficult. Presenteeism is a multidimensional problem, and a theoretical foundation is needed to explain the presenteeism of clinical nurses.

• Journal of the Korean Institute of Gas
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• v.18 no.4
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• pp.21-26
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• 2014

In this study, the explosion characteristic of aluminium powders have been investigated as a function of particle size using by a 20 L dust explosion apparatus (K$\ddot{u}$hner). The tested aluminium particle sizes were the volume mean diameter of 16, 33 and $88{\mu}m$. The lower explosion limit increases gradually with the increasing of dust particle diameter, respectively 40, 60, $125g/m^3$ in mean diameter of 16, 33 and $88{\mu}m$. Also the increase in particle size for each aluminum dusts was found to cause an decrease in explosion pressure and Kst of dust explosion index, and a increase in the lower explosion concentration. Research results may have important implications for aluminum powders utilization and safety operation.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.24 no.3
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• pp.371-382
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• 2014

Objectives: This study was undertaken in order to examine how musculoskeletal disorder(MSD) symptoms were affected by particular factors and then to explore control strategies to prevent MSDs in general hospital nurses. Materials: This, as part of a large study, was conducted using a set of information on literature review, questionnaire survey and focus group interview. It obtained prevalence and factors of MSD symptoms and examined how MSD symptoms were distributed and affected by the factors in nurses working at 15 general hospitals across Korea. The factors were personal factors, work organization, nursing tasks, physical factors and psychosocial factors. Results: A total of 501 nurses were determined as subjects. The highest MSD symptom prevalence was 61% for the shoulder, among body parts, followed by leg/feet(55%), low back(51%), neck(42%), wrist(38%), and elbow(21%). Prevalence for the whole body was 80%. Odds ratios ranged from 0.4 to 22.4 in logistic regression analyses. The symptoms were significantly attributed to factor variables such as body mass index, current health status, daily work time, nursing task, pooled-physical factors, ergonomic factors, work load, interpersonal conflict, and job insecurity. Conclusions: Two or more factor variables were significant, depending on body part, for MSD systems in the general hospital nurses. It was noticeable that physical factors, such as pooled-physical factors, ergonomic factors or work load, were selectively significant for MSD symptoms in all body parts, indicating that such information should be used for prevention of MSDs in the hospital sector.

• Korean journal of communication and information
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• v.35
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• pp.181-210
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• 2006

This frame analysis attempts to shed light on the process by which the Korean press constructs crisis as social reality through a series of risk reporting on food safety. Based on the FSSI(Food Safety Sentiment Index) developed by KIHASA(Korea Institute for Health and Social Affairs), 11 cases of food safety reports from 1989 to 2005 were collected from the Korean Integrated News Database System(KINDS) and analyzed to yield the following salient features: risk diffusion frame; attribution of responsibility frame; conflict frame. It was observed that the press exhibited a tendency to approach the food safety incidents from a bi-polarized perspective, amplifying dichotomy between the victim and the perpetrator rather than treating them as scientific, or environmental hazards that require precise and synthesized information for resolution. This occupational habit of attributing status to agents of news was also found to contribute towards construction of crisis as social reality.

• Korean Chemical Engineering Research
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• v.62 no.1
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• pp.27-35
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• 2024

Fuel gases such as methane and propane are used in explosion hazardous area of domestic plants and can form non-uniform mixtures with the influence of process conditions due to leakage. The fire-explosion risk assessment using literature data measured under uniform mixtures, damage prediction can be obtained the different results from actual explosion accidents by gas leaks. An explosion characteristics such as explosion pressure and flame velocity of non-uniform gas mixtures with concentration change similar to that of facility leak were examined. The experiments were conducted in a closed 0.82 m long stainless steel duct with observation recorded by color high speed camera and piezo pressure sensor. Also we proposed the quantification method of non-uniform mixtures from a regression analysis model on the change of concentration difference with time in explosion duct. For the non-uniform condition of this study, the area of flame surface enlarged with increasing the concentration non-uniform in the flame propagation of methane and was similar to the wrinkled flame structure existing in a turbulent flame. The time to peak pressure of methane decreased as the non-uniform increased and the explosion pressure increased with increasing the non-uniform. The ranges of K_G (Deflagration index) of methane with the concentration non-uniform were 1.30 to 1.58 [MPa·m/s] and the increase rate of K_G was 17.7% in methane with changing from uniform to non-uniform.

• Journal of agricultural medicine and community health
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• v.25 no.2
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• pp.245-263
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• 2000

This study was conducted to provide the basic data about the health effects of pesticide exposure among farmers for agricultural health study. We analyzed 412 self-administered questionnaires collected from the male farmers who spray pesticides in Kyoung-ju area, Korea. Survey questions were about chronic symptoms, acute symptoms while pesticide spraying, pesticide intoxication accident, safety rules, protective equipments etc. The correlations among the variables related to pesticide exposure and the factors in acute pesticide poisoning and chronic symptoms of farmers were also analyzed. For chronic symptoms, the prevalence of 'tiredness and languor', 'lumbago', 'nocturia', 'shoulder pain', 'numbness', and, for acute symptoms while pesticide spraying, the experience rate of 'itching sense of skin', 'dizziness/headache', 'fatigue', 'eye glaring' were high compared with other symptoms. For 'experience of intoxication accident by pesticide in family', 7.1% of the subjects experienced the accident and the causes were pesticide spraying, food contamination by pesticide, suicide etc. Among safety rules, 'take a bath after spraying', 'change clothes after spraying' were kept relatively well, and, for protective equipments, hat, boots, mask, gloves, protective clothes(lower) were put on relatively well. The factors associated with acute pesticide poisoning were the extent of keeping safety rules, spraying time, orchard cultivation, agricultural area and spraying days per year etc. And the factors associated with chronic symptoms were acute symptoms while pesticide spraying, agricultural area, farming career, extent of keeping safety rules, extent of agricultural work and the pesticide exposure index etc. From these results, it is suggested that to reduce the health effects by pesticide exposure among farmers, the education to promote to keep safety rules and wear protective equipments, and information services should be recommended. And further studies on the long term health effects of pesticide exposure among farmers are required.