Evaluation of the Exposure to Environmental Pollutants Emanating from National Industrial Complexes

The industrial complexes built during the course of economic development in South Korea played a pivotal role in the country’s rapid economic growth. However, this growth was accompanied by health problems due to the pollutants released from the industrial complexes inevitably located near residential areas, given the limited land area available in South Korea. This study was conducted to evaluate the exposure to each pollutant emanating from industrial complexes for residents living in nearby areas, and to determine the substances requiring priority attention in future surveys. Pollutants were comprehensively categorized according to their emission and exposure levels based on data previously collected from the study areas. The emission, ambient concentration, and biomarker concentration levels of major pollutants emitted from eight national industrial complexes (Ulsan, Pohang, Gwangyang, Yeosu, Chungju, Daesan, Sihwa, and Banwol) were determined and tabulated. Each of the values was compared with the national/local average values, reference values, or control area concentrations depending on availability. Substances with completed exposure pathways and with high values for emissions, ambient concentrations, and biomarker concentrations were considered the substances posing exposure risks to the residents living near the corresponding industrial complex. The substances requiring continuous monitoring or supplementary exposure investigation were also categorized and presented. Lead and benzene had higher values for emissions, ambient concentrations, and biomarker concentrations in the Ulsan Industrial Complex area; thus, they were most likely to pose exposure risks to residents living in the area’s neighborhoods. In other areas, styrene, xylene, cadmium, nitrogen oxide, trichloroethylene, nickel, manganese, and chromium required continuous monitoring, and arsenic, nickel, manganese, and chromium required biomarker measurements. In conclusion, the substances identified and categorized in this study need to be given appropriate attention in future surveys on exposure risks and health effects related to industrial complexes

Directions for and prospects of the Environmental Health Study in Korean National Industrial Complexes (EHSNIC): A proposal for the third phase of the EHSNIC

The Environmental Health Study in the Korean National Industrial Complexes (EHSNIC) is a project that aims to monitor the exposure and health effects of environmental pollution among residents of national industrial complexes, as well as propose appropriate environmental health measures. Since its launch in 2003, this project has been initiated in eight national industrial complexes. Currently, it is necessary to review the accomplishments and limitations of the phases 1 and 2 of this project, and establish the direction of the upcoming the phase 3. Thus, the present study has developed principles and goals for the phase 3, considering the rationale and justification of the EHSNIC, and presented specific research contents accordingly. In the phase 3, it is important to improve the methods for exposure assessment and evaluation of health effects, in order to identify clearly the association between the pollutants released from industrial complexes and their health impacts, to develop and to reinforce communication strategies to promote participation of residents of communities near industrial complexes. Nonetheless, it is also important to maintain the basic goal of continuously monitoring the level of exposure to and health effects of environmental pollutants

Real-World Failure Prevention Framework for Manufacturing Facilities Using Text Data

In recent years, manufacturing companies have been continuously engaging in research for the full implementation of smart factories, with many studies on methods to prevent facility failures that directly affect the productivity of the manufacturing sites. However, most studies have only analyzed sensor signals rather than text manually typed by operators. In addition, existing studies have not proposed an actual application system considering the manufacturing site environment but only presented a model that predicts the status or failure of the facility. Therefore, in this paper, we propose a real-world failure prevention framework that alerts the operator by providing a list of possible failure categories based on a failure pattern database before the operator starts work. The failure pattern database is constructed by analyzing and categorizing manually entered text to provide more detailed information. The performance of the proposed framework was evaluated utilizing actual manufacturing data based on scenarios that can occur in a real-world manufacturing site. The performance evaluation experiments demonstrated that the proposed framework could prevent facility failures and enhance the productivity and efficiency of the shop floor

Effects of pressure and temperature conditions on thermodynamic and kinetic guest exchange behaviors of CH4 - CO2 + N-2 replacement for energy recovery and greenhouse gas storage

Both natural gas production and CO2 sequestration can be simultaneously achieved in natural gas hydrates (NGHs) by using a guest swapping technique. In this study, the effects of replacement pressure (10.0-18.5 MPa) and temperature (274.2-277.2 K) conditions on the guest exchange behaviors of CH4 - CO2 + N-2 replacement were investigated, focusing on the extent of replacement and replacement kinetics. At 274.2 K, the extent of replacement increased with injection pressure of CO2 (20%) + N-2 (80%) gas, which is mainly attributed to a larger N-2 inclusion at a higher pressure. At a higher temperature, the extent of replacement did not change, but CO2/N-2 ratio in the replaced hydrates decreased slightly. An increase in the pressure led to an accelerated CO2 inclusion rate in the large (5(12)6(2)) cages at the initial stage and an enhanced N-2 inclusion in the small (5(12)) cages at the final stage. The enhanced replacement kinetics at a higher temperature is attributable to the increased inclusion rates of both CO2 and N-2 at the initial stage of replacement. The results provide valuable insights into the guest swapping mechanism of CH4 - CO2 + N-2 replacement occurring in NGH reservoirs with various locations and environments. (C) 2021 Elsevier Ltd. All rights reserved

Influence of structural transformation on guest exchange behavior in the sII hydrate-(CO2 + N-2) replacement for energy recovery and CO2 sequestration

In this study, the guest exchange behavior in the sII (CH4 + C3H8) hydrate - (CO2 + N-2) replacement at various CO2 concentrations was experimentally investigated to elucidate the influence of the structural transformation of the initial sII hydrate on the replacement efficiency at different feed gas compositions and injecting pressures. The extent of replacement, structural identification, and cage occupancy of guest molecules in the replaced hydrates were determined by a combination of gas chromatography (GC), powder X-ray diffraction (PXRD), and 13C NMR spectroscopy. The experimental results demonstrated that injecting feed gas with higher CO2 concentrations (%CO2) at a higher partial pressure of CO2 (PCO2) resulted in a higher weight fraction of sI hydrates (a greater degree of structural transformation from sII to sI) after replacement and consequently, higher replacement efficiency. The newly formed sI hydrates after replacement were primarily composed of CO2 and N-2. The guest-inclusion behavior in the small (5(12)) cages of the sII hydrates after replacement, as revealed by Rietveld refinement of the PXRD patterns, had a dominant influence on the total CO2/N-2 ratios in the replaced hydrates. The findings of this study offer valuable insights into the guest exchange mechanism occurring in sII hydrates during flue gas injection and can aid in estimating the optimal compositions of flue gas for energy recovery and CO2 sequestration through guest replacement in natural gas hydrates

NaCl-induced enhancement of thermodynamic and kinetic CO2 selectivity in CO2 + N-2 hydrate formation and its significance for CO2 sequestration

The importance of carbon capture and storage (CCS) has recently been emphasized owing to the ever-increasing global warming. Direct CO2 sequestration in marine sediments is an attractive option for CO2 storage, and some amount of injected CO2 can be stored in the form of solid gas hydrates. In this study, the effects of NaCl on the hydrate phase equilibria, thermodynamic and kinetic CO2 selectivity, and time-dependent growth behaviors of CO2 + N-2 hydrates were experimentally investigated to elucidate their implications for hydrate-based CO2 sequestration. The presence of NaCl shifted the equilibrium conditions of CO2 + N-2 hydrates to the higher -pressure or lower-temperature region, whereas it increased thermodynamic CO2 selectivity at a specified temperature and pressure, which was also confirmed by the pressure-composition diagram. As revealed by powder X-ray diffraction analysis, the conversion into CO2 + N-2 hydrate was lower in the saline water system because of the lower initial driving force and gradual salt enrichment in the residual solution during hydrate growth. In situ Raman spectroscopic measurements demonstrated that CO2 was kinetically selective at the early stage of CO2 + N-2 hydrate formation and that kinetic CO2 selectivity was more noticeable in the saline water system. The overall results provide an in-depth understanding of the role of salts in CO2 + N-2 hydrate formation and thus offer valuable insights into hydrate-based CO2 storage and geological CO2 sequestration

Magnetic field detwinning in feTe

© 2019, Korea Institute of Applied Superconductivity and Cryogenics. All rights reserved.Iron-based superconductors (IBSs) possess nematic phases in which rotational symmetry of the electronic structure is spontaneously broken. This novel phase has attracted much attention as it is believed to be closely linked to the superconductivity. However, observation of the symmetry broken phase by using a macroscopic experimental tool is a hard task because of naturally formed twin domains. Here, we report on a novel detwinning method by using a magnetic field on FeTe single crystal. Detwinning effect was measured by resistivity anisotropy using the Montgomery method. Our results show that FeTe was detwinned at 2T, which is a relatively weak field compared to the previously reported result. Furthermore, detwinning effect is retained even when the field is turned off after field cooling, making it an external stimulation-free detwinning metho

Determination of the Parameter Sets for the Best Performance of IPS-driven ENLIL Model

Interplanetary scintillation-driven (IPS-driven) ENLIL model was jointly developed by University of California, San Diego (UCSD) and National Aeronaucics and Space Administration/Goddard Space Flight Center (NASA/GSFC). The model has been in operation by Korean Space Weather Cetner (KSWC) since 2014. IPS-driven ENLIL model has a variety of ambient solar wind parameters and the results of the model depend on the combination of these parameters. We have conducted researches to determine the best combination of parameters to improve the performance of the IPS-driven ENLIL model. The model results with input of 1,440 combinations of parameters are compared with the Advanced Composition Explorer (ACE) observation data. In this way, the top 10 parameter sets showing best performance were determined. Finally, the characteristics of the parameter sets were analyzed and application of the results to IPS-driven ENLIL model was discussed

Effect modification of consecutive high concentration days on the association between fine particulate matter and mortality: a multi-city study in Korea

OBJECTIVES Although there is substantial evidence for the short-term effect of fine particulate matter (PM2.5) on daily mortality, few epidemiological studies have explored the effect of prolonged continuous exposure to high concentrations of PM2.5. This study investigated how the magnitude of the mortality effect of PM2.5 exposure is modified by persistent exposure to high PM2.5 concentrations. METHODS We analyzed data on the daily mortality count, simulated daily PM2.5 level, mean daily temperature, and relative humidity level from 7 metropolitan cities from 2006 to 2019. Generalized additive models (GAMs) with quasi-Poisson distribution and random-effects meta-analyses were used to pool city-specific effects. To investigate the effect modification of continuous exposure to prolonged high concentrations, we applied categorical consecutive-day variables to the GAMs as effect modification terms for PM2.5. RESULTS The mortality risk increased by 0.33% (95% confidence interval [CI], 0.16 to 0.50), 0.47% (95% CI, -0.09 to 1.04), and 0.26% (95% CI, -0.08 to 0.60) for all-cause, respiratory, and cardiovascular diseases, respectively, with a 10 μg/m3 increase in PM2.5 concentration. The risk of all-cause mortality per 10 μg/m3 increase in PM2.5 on the first and fourth consecutive days significantly increased by 0.63% (95% CI, 0.20 to 1.06) and 0.36% (95% CI, 0.01 to 0.70), respectively. CONCLUSIONS We found increased risks of all-cause, respiratory, and cardiovascular mortality related to daily PM2.5 exposure on the day when exposure to high PM2.5 concentrations began and when exposure persisted for more than 4 days with concentrations of ≥35 μg/m3. Persistently high PM2.5 exposure had a stronger effect on seniors