Comparison of Phenol Removal between Electrochemical Reaction and Plasma Reaction
Kim, Dong-Seog;Park, Young-Seek 905
https://doi.org/10.5322/JESI.2016.25.7.905 PDF KSCI
The characteristics of phenol removal and $UV_{254}$ matters variance were investigated and compared by the variation of operating factors (NaCl concentration, air flow rate, initial phenol concentration) in electrochemical reaction (ER) and dielectric barrier discharge plasma reaction (DBDPR), respectively. The phenol removal rate was shown as $1^{st}$ order both in ER and DBDPR. Also, the absorbance of $UV_{254}$ matters which means aromatic intermediates was analyzed to investigate the complete phenol degradation process. In ER, the phenol degradation and aromatic intermediates production rates increased by the increase of NaCl concentration. However, in DBDPR, the variation of NaCl concentration had no effect on the degradation of phenol and $UV_{254}$ matters. Air flow rate had a little effect on the removal of phenol and the variation of $UV_{254}$ matters in ER. The phenol removal rate in ER was a little higher than that in DBDPR. The produced $H_2O_2$ and $O_3$ amounts in ER were 2 times and 10 times higher than those in DBDPR. The chlorine intermediates ($ClO_2$ and free chlorine) were produced in ER, however, they were not produced in DBDPR.
The Composition and Characteristics of the Coastal Space of Chongqing: An Interpretative Study Based on the Ten-year Draft Construction Plan of the Alternate Capital
Kong, Ming-liang;Du, Chun-lan;Mao, Hua-song;Zhang, Jun-hua;Ham, Kwang-min;Jo, Hyunju 917
This study focused on the buildings, wharves, and parks of the coastal space of Chongqing based on the ten-year construction draft plan of the alternate capital. From an investigation of these three components according to their type, structure, terrain, function, spatial layer, and so on, the following conclusions were drawn: The coastal space of Chongqing is composed of three different layers. The first and second layers consisted of the two-river intersection basin with the transportation and commemorative space at the center, the Yangtze River basin with the commercial space at the center, and the Jialing River with the military and recreational space at the center. The third-layer is centered around the commemorative space. The coastal space of Chongqing manifested the limitations of the times, its traditionality, and an integrated development process.
Release of Oxygen from a Nano-sized Water Droplet Observed using Molecular Dynamics
Lee, Chang-Han;Ambrosia, Matthew Stanley 927
Dissolved oxygen is necessary for many biological processes as well as many industrial practices. Dissolved oxygen released from water in dissolved air flotation (DAF) systems can be have many different applications. However, DAF systems are very costly to operate. To develop more efficient DAF systems, a deeper understanding of the process of oxygen being released from water is required. In this study, molecular dynamics (MD) simulations were used to simulate 100 oxygen molecules surrounded by 31002 water molecules at temperatures ranging from $0^{\circ}C$ to $100^{\circ}C$. Simulations were carried out for 10 ns, during which, in most cases, all the oxygen molecules were released from the water droplet. With MD simulations, visualization of the molecules escaping the water droplet was possible, which aided the understanding of the interactions between molecules at the nano-scale. The results showed that as the oxygen molecules moved near the edge of the water droplet that the oxygen molecules hesitated before escaping the water droplet or returned to the interior of the water droplet. This was because of the attractive forces between the water and oxygen molecules. Moreover, after most of the oxygen molecules were released from the droplet, some were found to return to the droplet's edge or even the interior of the droplet. It was also confirmed that oxygen molecules were released at a faster rate at higher temperatures.
Analysis of Exclusive Causality between Environmental Factors and Cell Number of Cyanobacteria in Guem River
Kim, Yeonhwa;Lee, EunHyung;Kim, Kyunghyun;Kim, Sanghyun 937
Algal blooming in 4 major rivers introduces substantial impacts to water front activity. Concentrations of algae are increasing at major points along the Geum River. Ecosystem food webs can be affected by algal blooming because blue-green algae release toxic materials. Even though there have been many studies on blue-green algae, its causality to environmental factors has not been completely determined yet. This study analyzed the exclusive correlation between various hydrometeorological, water quality, and hydrologic variables and the cell number of cyanobacteria to understand causality of blue-green algae in the Geum River. A prewhitening process was introduced to remove the autocorrelation structure and periodicity, which is useful to evaluate the effective relationship between two time series.
A Study on Optimization of Thermophysiological Indices for Harbor Workers in Summer: Improvement of MENEX Model's Input Data Considering the Work Environment
Yun, Jinah;Hwang, Mi-Kyoung;Kim, Yoo-Keun 951
To prevent increasing instances of heat-related illnesses due to heat waves generated by climate change, a customized thermal environment index should be developed for outdoor workers. In this study, we conducted sensitivity analysis of the Masan harbor during a heat wave period (August 9th to 15th, 2013) using the MENEX model with metabolic rate and clothing-insulation data, in order to obtain realistic information about the thermal environment. This study shows that accurate input data are essential to gather information for thermophysiological indices (PST, DhR, and OhR). PST is sensitive to clothing insulation as a function of clothing. OhR is more sensitive to clothing insulation during the day and to the metabolic rate at night. From these results, it appears that when exposed to high-temperature thermal environments in summer, wearing highly insulated clothing and getting enough rest (to lower the metabolic rate) can aid in preventing heat-related illnesses. Moreover, in the case of high-intensity harbor work, quantification of allowed working time (OhR) during heat waves is significant for human health sciences.
A Study on the Analysis User Preference for Urban Healing Forest Park Planning Methods
Kim, Jeong-Ho;Seo, Han-min;Oh, Deuk-Kyun;Yoon, Yong-Han 963
A survey was performed to present a scheme for building a healing forest park inside a city in consideration of the fact that healing forests are located in non-urban areas because of their nature, and are therefore not conveniently accessible to urban population (n=196). As a result, among 196 respondents to the survey, 74.5% indicated that it was necessary to build an urban healing forest park. In the case of the expected usage pattern, were an urban forest park to be built, the largest proportion responded that it would be used to "walk", followed by "rest and meditation" and then "meeting/talk/date". An analysis showed that the largest proportion responded that they factor in "Accessibility" (48%), followed by "Park condition" (16.8%), and "Vegetation type" (12.2%). According to the analysis of usage preference for healing therapy, it was shown that the largest proportion preferred "Terrain therapy" (37.8%), followed by "Exercise therapy" (19.9%), and "Naturopathy" (18.9%). The factor anlaysis of usage preference regarding urban healing forest park facilities showed that the components were divided into "Operation facilities" and "Natural healing space", and the largest proportion preferred "Trails for healing", followed by "Space or forest for meditation" and "Health promotion center", and then "Facilities for a exercise therapy". In building an urban healing forest park, we think that it is effective to introduce zones and facilities in consideration of park characteristics that are centered on everyday behaviors, such as taking a walk, which differ from those of healing forests located in non-urban areas.
A Study on Changes in CO2 Concentrations and their Impact on Radiative Forcing at Urban Center and Background Sites on Jeju Island in Recent Years
Lee, Soo-Jeong;Song, Sang-Keun;Park, Yeon-Hee 973
The spatial and temporal variations of $CO_2$ concentrations and radiative forcing (RF) due to $CO_2$ were examined at urban center (Yeon-dong) during 2010-2015 and background sites (Gosan) during 2010-2014 on Jeju Island. The RF at the two sites was estimated based on a simplified expression for calculating RF for the study period. Overall, annual mean $CO_2$ concentrations at the Yeon-dong and Gosan sites have gradually increased, and the concentrations were higher at Yeon-dong (401-422 ppm) than at Gosan (398-404 ppm). The maximum $CO_2$ concentrations at the two sites were observed in winter or spring, followed by fall and summer, with higher concentrations at Yeon-dong. The RF at Yeon-dong (annual mean of up to $0.70W/m^2$ in 2015) was higher than that at Gosan (up to $0.46W/m^2$ in 2014), possibly because of higher $CO_2$ concentrations at Yeon-dong resulting from population growth and human activities (e.g., fossil fuel combustion). The highest monthly mean RFs at Yeon-dong (approximately $0.92W/m^2$) and Gosan ($0.52W/m^2$) were observed in spring 2015 (Yeon-dong) and spring 2013 (Gosan), whereas the lowest RFs (0.17 and $0.31W/m^2$, respectively) in fall 2011 (Yeon-dong) and summer in 2012 (Gosan).
Content Analysis of Main National Environmental Dispute Cases from Five Recent Years
Park, Jeong-Ho;Yang, Sung-Bong 989
In this study, we analyzed the content and compensation factors of 337 cases of national environmental disputes from five recent years (2000~2014). Causes of damage were noise-vibration in 234 cases (69%), sunlight in 48 cases (14%), air pollution in 19 cases (6%), water pollution in 15 cases (4%), odor in 13 cases (4%), and others factors in 8 cases (3%). Sources of damage were construction in 224 cases (66%), structures in 36 cases (11%), vehicle on road in 31 cases (9%), industry in 18 cases (5%), environmental facility in 11 cases (3%), livestock facility in 6 cases (2%), and other sources in 11 cases (3%). From the results of logistic regression analysis, important factors associated with compensation were found to be damage amount, damage distance, zoning districts, source, and administrative disposition.
Diagnosis and Renovation of a Time-worn Rapid Sand Filter used for Drinking Water Treatment
Kim, Sang-Goo;Park, Hyun-Seog;Son, Hee-Jong;Lee, Jeong-Gyu;Ryu, Dong-Choon;Yoo, Pyung-Jong 999
The H water treatment plant has been operating since 1982 and has had no renovation. It is assumed that the filters have been operated for more than 30 years and therefore are deteriorated. Many of the filters show an unequal state of air scouring during backwashing. For this study one filter, which was presumed most deteriorated among eighteen filters, was selected as a model filter for renovation. Some of the effects seen after renovation of the underdrain system were a lower average filtrated turbidity by approximately 0.02 NTU and an equal backwash state throughout the filter bed. Sand wash efficiencies by backwash before renovation of the underdrain system were 28%, 8%, and 5% at the surface, 50 cm depth, and 100 cm depth, respectively, and after renovation of the underdrain system were 94%, 26%, and 15%, respectively. The standard deviation of the effective sand size was 0.025-0.033 mm before renovation of the underdrain system and 0.002-0.011 mm after renovation of the underdrain system, meanings there was equal backwash pressure throughout the filter. Filtration time after renovation was approximately 2 times longer than before renovation.
Characteristics of Storm Runoff and Analysis of Its Correlation with Forest Properties
Chung, WooJin;Chang, SoonWoong 1007
https://doi.org/10.5322/JESI.2016.25.7.1007 PDF KSCI
Environmental policy implementation has been strengthened to protect the source waters in Korea and to improve their water quality. Increasing of non-point source caused water quality problem continuously. Research on runoff from forests, which occupy over 65% of the land in korea, is insufficient, and studies on the characteristics and influences of storm runoff are necessary. In this study, we chose to compare the effects of land use in the form of two types of forest distribution and then gathered data on storm characteristics and runoff properties during rainfall events in these areas. Furthermore, the significance and influences of the discharges were analyzed through correlation analysis, and multilateral runoff characteristics were examined by deducing a formula through $COD_{Mn}$ and TOC regression analysis. At two forest points, for which the basin areas differed from each other, flow changed according to storm quantity and intensity. The peak discharge at point A, where the basin area was big, was high, whereas water-quality fundamental items (BOD, $COD_{Mn}$, and SS) and TOC density were high at point B where the slope and storm intensity were high. Effects of dissolved organic matter were determined through correlation analysis, and the regression formulas for $COD_{Mn}$ and TOC were deduced by regression analysis. It is expected that the data from this study could be useful as basic information in establishing forest management measures.
A Study of the Characteristics of Input Boundary Conditions for the Prediction of Urban Air Flow based on Fluid Dynamics
Lee, Tae-Jin;Lee, Soon-Hwan;Lee, Hwawoon 1017
Wind information is one of the major inputs for the prediction of urban air flow using computational fluid dynamic (CFD) models. Therefore, the numerical characteristics of the wind data formed at their mother domains should be clarified to predict the urban air flow more precisely. In this study, the formation characteristics of the wind data in the Seoul region were used as the inlet wind information for a CFD based simulation and were analyzed using numerical weather prediction models for weather research and forecasting (WRF). Because air flow over the central part of the Korean peninsula is often controlled not only by synoptic scale westerly winds but also by the westerly sea breeze induced from the Yellow Sea, the westerly wind often dominates the entire Seoul region. Although simulations of wind speed and air temperature gave results that were slightly high and low, respectively, their temporal variation patterns agreed well with the observations. In the analysis of the vertical cross section, the variation of wind speed along the western boundary of Seoul is simpler in a large domain with the highest horizontal resolution as compared to a small domain with the same resolution. A strong convergence of the sea breeze due to precise topography leads to the simplification of the wind pattern. The same tendency was shown in the average vertical profiles of the wind speed. The difference in the simulated wind pattern of two different domains is greater during the night than in the daytime because of atmospheric stability and topographically induced mesoscale forcing.
Assessment of Global Air Quality Reanalysis and Its Impact as Chemical Boundary Conditions for a Local PM Modeling System
Lee, Kangyeol;Lee, Soon-Hwan;Kim, EunJi 1029
The initial and boundary conditions are important factors in regional chemical transport modeling systems. The method of generating the chemical boundary conditions for regional air quality models tends to be different from the dynamically varying boundary conditions in global chemical transport models. In this study, the impact of real time Copernicus atmosphere monitoring service (CAMS) re-analysis data from the modeling atmospheric composition and climate project interim implementation (MACC) on the regional air quality in the Korean Peninsula was carried out using the community multi-scale air quality modeling system (CMAQ). A comparison between conventional global data and CAMS for numerical assessments was also conducted. Although the horizontal resolution of the CAMS re-analysis data is not higher than the conventionally provided data, the simulated particulate matter (PM) concentrations with boundary conditions for CAMS re-analysis is more reasonable than any other data, and the estimation accuracy over the entire Korean peninsula, including the Seoul and Daegu metropolitan areas, was improved. Although an inland area such as the Daegu metropolitan area often has large uncertainty in PM prediction, the level of improvement in the prediction for the Daegu metropolitan area is higher than in the coastal area of the western part of the Korean peninsula.
Effects of Replacing Corn Meal with Barely on Growth Performance, Nutrient Digestibility, and Blood Metabolites in Growing Pigs
Kim, Hoi-Yun;Kim, Sam-Churl;Song, Young-Min 1043
A total of 16 growing pigs (Landrace${\times}$Yorkshire${\times}$Duroc, average weight $71{\pm}2kg$) were used in this experiment for 24 days to determine the effect of replacing ground corn with barley varieties on growth performance, nutrient digestibility, and blood metabolites. Each pig was housed individually in a metabolic cage with a nipple waterer and feeder. Four dietary treatments included control (a corn and soybean meal-based diet) and 3 barley varieties (Youngyang, Wooho, or Yuyeon barley replacing 40% of ground corn). Growth performance and nutrient digestibility were not affected by replacement of 40% of ground corn with one of the three barley varieties (p > 0.05), but final body weight was. As for blood characteristics, pig treated with all of the barley treatments had no effect (p > 0.05) on total protein, albumin, aspartate aminotransferase (AST), alanine aminotransferase (ALT), lactate dehydrogenase (LD), and glucose in comparison with control; however, there was a difference in high density lipoprotein (HDL)-cholesterol levels between the control and all of the barley replaced treatment groups (p < 0.05). In conclusion, in spite of statistically significant differences, each of the three barley varieties is a suitable substitute for ground corn in the diet of growing and fattening pigs without adverse effects on growth performance, nutrient digestibility, and blood characteristics.