• Journal of Korean Society of Water and Wastewater
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• v.29 no.5
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• pp.551-557
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• 2015

The TMDL (Total Maximum Daily Load) has been used to determine the water quality target. LDC (Load Duration Curve) based on hydrology has been used to support water quality assessments and development of TMDL. Also FDC (Flow Duration Curve) analysis can be used as a general indicator of hydrologic condition. The LDC is developed by multiplying FDC with the numeric water quality target of the factor for the pollutant of concern. Therefore, this study was to create LDC using the stream flow data and numeric water quality target of BOD and T-P in order to evaluate the pollutant load characterization by flow conditions in Heukcheon stream. When it is to be a high-flows condition, BOD and T-P are necessary to manage. BOD and T-P did not satisfy the numeric water quality target for both seasons (spring and summer). In order to meet the numeric water quality target in Heukcheon stream, management of non point source pollutant is much more important than that of point source pollutant control.

• Applied Chemistry for Engineering
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• v.10 no.2
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• pp.242-246
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• 1999

For the fluorination of $CF_2Cl_2$, the yield of $CF_4$ was found to be increased with the contact time and the reaction temperature. When the mole ratio of HF/$CF_2Cl_2$ is 3 or above, the yield of $CF_4$ was attained to 100% at $370^{\circ}C$ and contact time of 3 seconds. In the case of the fluorination of $CCl_4$ with HF, the yield of $CF_4$ was obtained above 90% at the reaction temperature of $500^{\circ}C$, the contact time of 3 seconds, and the mole ratio of HF/$CCl_4$ of 5.

• Journal of Environmental Health Sciences
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• v.30 no.3
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• pp.272-282
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• 2004

Stress is a primary health promotion issue in worksite research because psychological distress is closely related not only to workers　 health status but also to their job performance. This study identified the work environment and work condition factors affecting workers　 stress symptoms among the Korean manufacturing factory workers. A total of 7,818 factory workers employed in 1,562 manufacturing companies participated in the Korean nation-wide occupational health survey conducted by the Korean Occupational Safety and Health Agency in 2003. Participants were selected by the stratified proportional sampling process by standardized industry classification, company size, and locations. Trained interviewers visited the target companies and interviewed the factory workers randomly selected in each company. Work environments included physical work environments (temperature, noise, hazardous organic compounds, and so on) and psychological work environments (job demands, job control, and social support at work), and work conditions included daily working hour, rest time, and so on. Men were 71.5% and the mean age was 34.0 years old. The average working period in the present company was 6.9 years. The average stress score was 26.2 under the perfect score, 50, which means the moderate level of stress. Perceived stress had significant correlations with young age, poor physical work environment, high fatigue, bad perceived health status, and high job demands in Pearson's simple correlation analysis. Perceived health status and perceived fatigue explained 21% variance of stress symptoms and the work environment factor explained 4.8% of that; however, work condition did not have the sufficient effect. In particular, psychosocial work environment variables (job demand, job control, and social support at work) had a clear effect on stress symptoms rather than the physical work environments. Poor perceived health status, severe perceived fatigue, poor physical work environment, high job demands, low social support, heavy alcohol consumption and little exercise were significantly related to high stress symptoms in the Korean manufacturing workers.

• International Journal of Concrete Structures and Materials
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• v.11 no.1
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• pp.59-68
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• 2017

Mercury intrusion and nitrogen sorption porosimetry were employed to investigate the pore structure of calcium sulfoaluminate ($C{\bar{S}}A$) and portland cement pastes with cement-to-water ratio (w/c) of 0.40, 0.50, and 0.60. A unimodal distribution of pore size was drawn for $C{\bar{S}}A$ cement pastes, whereas a bimodal distribution was established for the portland cement pastes through analysis of mercury intrusion porosimetry. For the experimental results generated by nitrogen sorption porosimetry, the $C{\bar{S}}A$ cement pastes have a smaller and coarser pore volume than cement paste samples under the same w/c condition. The relative dynamic modulus and percentage weight loss were used for investigation of the concrete durability in freeze-thaw condition. When coarse aggregate with good freeze-thaw durability was mixed, air entrained portland cement concrete has the same durability in terms of relative dynamic modulus as $C{\bar{S}}A$ cement concrete in a freeze-thaw environment. The $C{\bar{S}}A$ cement concrete with poor performance of durability in a freeze-thaw environment demonstrates the improved durability by 300 % over portland cement concrete. The $C{\bar{S}}A$ concrete with good performance aggregate also exhibits less surface scaling in a freeze-thaw environment, losing 11 % less mass after 297 cycles.

• Journal of The Korea Institute of Healthcare Architecture
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• v.23 no.4
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• pp.67-75
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• 2017

Purpose: This study is for the facility eligibility and improvement evaluation analysis for the patient care environment of 7 facilities which has national inpatient isolation units. Methods: For the evaluation, first of all, the patient care environment of national inpatient isolation units are scrutinized by the checklist which is used on from 2014 with the 4 fields of criteria : architectural planning and layout, general requirement and condition for operating the negative pressured isolated patient room, HVAC system, and waste water discharging system. Finally, the evaluation results are compared with that of 2014. Results: The result shows that the average value of facility eligibility is 89.3 percent and which is 8.9 percent higher than the value before the MERS occurred. Implications: It is clear that facility remodeling of 7 institutions is being performed continuously, and the result of facility eligibility evaluation is reflected on design of a new 21 national inpatient isolation units those are going to be constructed from 2016. Therefore, it is expected that this study is used as a practical reference to establish the criteria of patient care environment management and safety management for both infectious disease outbreak and general service condition.

• Journal of Soil and Groundwater Environment
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• v.17 no.5
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• pp.10-19
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• 2012

The aim of this study was to examine chemical and isotopic compositions of groundwater and lake water near an area contaminated by petroleum and to evaluate influence of petroleum on them during the period from March to August 2011. In dry season, $Ca^{2+}$ and $SO{_4}^{2-}$ were dominant in the groundwater and lake water and $Ca^{2+}$ and $HCO{_3}^-$ were significant in wet season. ${\delta}^{18}O$ and ${\delta}D$ of the groundwater and lake water were plotted near LMWL (${\delta}D=8.06{\delta}^{18}O+12.5$). ${\delta}^{18}O$ and ${\delta}D$ of the lake water did not show seasonal variation. However, ${\delta}^{18}O$ and ${\delta}D$ of the groundwater were enriched in wet season compared with those in dry season because of influence of small ponds around wells where evaporation losses were slightly experienced. Redox condition of most lake water was oxidation environment in contact with the atmosphere during the study period. However, redox condition of groundwater was transitional environment in dry season and oxidation environment in wet season because of influence of contaminant such as petroleum. In some groundwater, the concentrations of $NO{_3}^-$ in some groundwater were less than 1 mg/L because of denitrification. Also, $NO{_3}^-$ showed positive correlation with $SO{_4}^{2-}$ and weak negative correlation with $HCO{_3}^-$, because of influence of denitrification.

• Journal of Korean Society on Water Environment
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• v.35 no.2
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• pp.152-164
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• 2019

In this study, a Benthic Macroinvertebrates Family Index (BMFI) was developed using 100 indicator groups (99 families including Chironomidae with 2 phena). Families were assigned a score between 1 and 10 depending on their sensitivity to organic pollution. The BMFI was composed of the sensitivity and relative abundance of the indicator taxa. Sensitivity values of each group were generally similar to Biological Monitoring Working Party (BMWP) scores or Walley, Hawkes, Paisley, Trigg (WHPT) scores of UK, Japanese BMWP scores, and the FBI tolerance values of North America. However, sensitivity values of some taxa were significantly different from those of foreign countries, which seemed to have resulted from discrepancy in species composition, difference of taxonomic classification system, or methodological difference for estimation of sensitivity. As an annual average level, BMFI showed significant correlation with concentration of 5-day biochemical oxygen demand (BOD5) (correlation coefficient r = -0.80, n = 569 sites), total suspended solids (r = -0.68), and total phosphorus (r = -0.79). In addition, BMFI revealed strong correlation with Shannon-Weaver's species diversity (r = 0.85), Margalef's species richness (r = 0.85) and McNaughton's dominance (r = -0.84). Correlation between BMFI and water quality parameters or community indices such as species diversity did not show significant difference compared to that of species-level indices such as BMI (Benthic Macroinvertebrates Index). This means that BMFI is a more useful indicator in terms of easy identification of organisms. BMFI was used to assess the environmental status of 3,017 sites of Stream Ecosystem Survey conducted by the Korean Ministry of Environment between 2016 and 2018. As a result, about half of all sites appeared to be in good condition, and a quarter in poor condition.

• Journal of Electrochemical Science and Technology
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• v.13 no.2
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• pp.213-226
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• 2022

In the present study, the corrosion behavior of aluminum Al-7075 tempered (T-6 condition) alloy was evaluated by immersion testing and electrochemical testing in 1.75% and 3.5% NaCl environment at acidic, neutral and basic pH. The data obtained by both immersion tests and electrochemical corrosion tests (potentiodynamic polarization and electrochemical impedance spectroscopy tests) present that the corrosion rate of the alloy specimens is minimum for the pH=7 condition of the solution due to the formation of dense and well adherent thin protective oxide layer. Whereas the solutions with acidic and alkaline pH cause shift in the corrosion behavior of aluminum alloy to more active domains aggravated by the constant flux of acidic and alkaline ions (Cl^- and OH^-) in the media which anodically dissolve the Al matrix in comparison to precipitated intermetallic phases (cathodic in nature) formed due to T6 treatment. Consequently, the pitting behavior of the alloy, as observed by cyclic polarization tests, shifts to more active regions when pH of the solutions changes from neutral to alkaline environment due to localized dissolution of the matrix in alkaline environment that ingress by diffusion through the pores in the oxide film. Microscopic analysis also strengthens the results obtained by immersion corrosion testing and electrochemical corrosion testing as the study examines the corrosion behavior of this alloy under a systematic evaluation in marine environment.

• Journal of The Korea Institute of Healthcare Architecture
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• v.20 no.3
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• pp.7-15
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• 2014

Purpose: This study is to propose direction for healing environment design in hospital architecture considering the characteristics of elderly patients. The primary goal of a public hospital is providing cheap health care and quality service chance to the underprivileged and elderly in the dead zone. Compared to the rapid increase of the aged population and chronic diseases, Ministry of Health & Welfare is currently planning model of health promotion hospital in development plans of local based public hospital. Due to the increased elderly medical expenses, elderly patients' high utilization is considered. Methods: The literature on the design factors of healing environments were investigated. based on this, analyzed drawings of surveyed hospitals ward in architectural characteristics and observe and evaluate directly healing environment design through field surveys. Results: The design of hospital environment affects patient's therapeutic effect. There is no any official formula for hospital design but environment that architect create could be a big part of the healing process. To increase the quality of the environment, apply the characteristic factors and harmonize well as a human-centered healing environment. Implications: Healing environment design for the elderly is first necessary condition due to high proportion of elderly patients.

• Journal of the Korean housing association
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• v.23 no.5
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• pp.75-86
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• 2012

The primary purpose of this study is to prove the relationship between housing environment and mental health with depression and self-esteem in the republic of Korea. The raw data of 10,608 respondents, was gathered from the 4th wave of Korea Welfare Panel Study (KoWePS) in 2009. Some variables related to housing environment and mental health were selected in KoWePS' data. Data was analyzed by SPSS 19.0 and AMOS 17.0. The major results are as follow: 1) Householder economic variables significantly relate to housing environment and resident mental health. 2) Housing environment variables are significantly related to resident mental health, and these variables explain 4.3% of depression and 6.7% of self-esteem. 3) Throughout path analysis of economic, housing environment, and mental health variables, housing environment variable is a parameter. In conclusion, these results show that better quality of housing environment would contribute to the residents' better mental health.