• Journal of Korean Society of Environmental Engineers
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• v.27 no.1
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• pp.85-92
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• 2005

The performance of a novel fermentation process, adopting a sludge blanket type configuration for higher hydrolysis/acidogenesis of the municipal primary sludge, was investigated under batch and semi-continuous conditions with various pH and temperature conditions. This acid elutriation slurry reactor provided higher system performance with a short HRT (5 days) and higher acidogenic effluent quality under pH 9 and thermophilic ($55^{\circ}C$) conditions. The hydrolysis of the sludge was revealed to be significantly dependent on seasonal effects for sludge characteristics but with little impact on acidogenesis. Based on the rainy season at the optimum conditions, VFA production and recovery fraction ($VFA_{COD}/COD$) were $0.18\;g\;VFA_{COD}\;g^{-1}\;VSS_{COD}$ and 63%. As byproducts, nitrogen and phosphorus releasing were $0.006\;g\;N\;g^{-1}\;VSS_{COD}$ and $0.003\;g\;P\;g^{-1}\;VSS_{COD}$, respectively. For the mass balance in a full-scale plant($Q=158,880\;m^3\;day^{-1}$) based on the rainy season, the VFA and non-VFA(as COD) production were $3,110\;kg\;VFA_{COD}\;day^{-1}$ and $1,800\;kg\;COD\;day^{-1}$, resulting in an increase of organics of $31\;mg\;COD\;L^{-1}$ and $20\;mg\;VFA_{COD}\;L^{-1}$ and nutrients of $0.7\;mg\;N\;L^{-1}$ and $0.3\;mg\;P\;L^{-1}$ in the influent sewage. The economical benefit from this process application was estimated to be about $67 per $1,000m^3$ of sewage except for energy requirements and also, better benefits can be expected during the dry season. Also, the results revealed that the process has various additional advantages such as pathogen-free stabilized solids production, excellent solids control and economical benefits.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.3
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• pp.173-184
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• 2016

This study was carried out to understand the characteristic distributions of water temperature and salinity in accordance with seasons atound the Tongyeong and Geoje, based on a cluster analysis. Water temperatures in coastal areas were $1-2^{\circ}C$ higher than those in open seas when in the spring, autumn and winter. In particular, a south-northward isothermal line was established at the bottom layer in the winter of 2014, unlikely to the surface layer. In addition, a south-northward isohaline was also established at the bottom layer in the winter of 2013. Therefore, we recognized that a moving pattern of water masses has also a difference since forming directions of those lines were not equivalent with each other between the surface and bottom layers. In contrast, stratification appeared in the summer with a roughly difference of water temperature of $10^{\circ}C$ and a salinity of 2-10 psu between the layers. A cluster analysis indicated that the southeastern coastal waters have three distinct water masses, even though some complicated situations exist due to the seawater inflow from the outside. However, the result of a cluster analysis turned out quite reasonable because the result of a regression analysis proved that it is appropriate, just except for the timing of a south-northward front formation.

• Journal of the Korean Society for Marine Environment & Energy
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• v.19 no.2
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• pp.144-150
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• 2016

In southwestern East Sea, we investigated the spatio-temporal distribution characteristics of particulate organic carbon (POC) and nitrogen (PON) in September 2011 (summer), January (winter) and May 2012 (spring). Although cold waters known as the origin upwelling in the surface layer of September were not observed, this periods showed high primary productivity because of high concentrations of chlorophyll, low percentage of non-autotrophic particulate fraction among POC calculated by POC/Chl-a ratio (27%) and low POC/PON ratio (6.2), which means active amino acid and protein synthesis, However, May, 2012 showed low primary productivity because of high percentage of non-autotrophic particulate fractions among POC (66%) and high POC/PON ratio (8.1), Although spring bloom and high primary productivity has been reported in the East Sea, high percentage of non-autotrophic particulate fractions in POC, observed in the East sea during the post 2012 spring, is suggested to be due to the increase of phaeo-pigment during post spring bloom. Thus, composition of particulate organic matter may have sensitively changed by marine environmental factors in spite of same season.

• Journal of Soil and Groundwater Environment
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• v.10 no.4
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• pp.54-61
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• 2005

An aquifer thermal energy storage (ATES) system can be very cost-effective and renewable energy sources, depending on site-specific parameters and load characteristics. In order to develop the ATES system which has certain hydrogeological characteristics, understanding the thermohydraulic process of an aquifer is necessary for a proper design of an aquifer heat storage system under given conditions. The thermohydraulic transfer for heat storage was simulated according to two sets of simple pumping and waste water reinjection scenarios of groundwater heat pump system operation in a two-layered aquifer model. In the first set of the scenarios, the movement of the thermal front and groundwater level was simulated by changing the locations of injection and pumping wells in a seasonal cycle. However, in the second set the simulation was performed in the state of fixing the locations of pumping and injection wells. After 365 days simulation period, the shape of temperature distribution was highly dependent on the injected water temperature and the distance from the injection well. A small temperature change appeared on the surface compared to other simulated temperature distributions of 30 and 50 m depths. The porosity and groundwater flow characteristics of each layer sensitively affected the heat transfer. The groundwater levels and temperature changes in injection and pumping wells were monitored and the thermal interference between the wells was analyzed to test the effectiveness of the heat pump operation method applied.

• Journal of The Korean Society of Grassland and Forage Science
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• v.40 no.2
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• pp.111-116
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• 2020

This study was conducted to determine the maintenance energy requirements of growing goats in order to establish an appropriate energy benefit system, to reduce feed costs and improve livestock productivity of goat farmers, and to present basic data for detailed specifications afterwards. This experiment was conducted as a group specification test for a total of 3 months, with 32 goats of three months age and conducted by four treatments with different energy levels (T1: NRC+0%, T2: NRC+10%, T3: NRC+20%, and T4: NRC+30%). The average daily gain was the highest in the treated with NRC + 10% of the energy level of the experimental diet, and the feed conversion ratio was in the range of 6.3 g to 7.3 g in the group feeding experiment. Although there was no significant difference in digestibility between treatments, the digestibility of dry matter, crude protein, and crude fat was higher in T2 treated with NRC + 10% than the other treatments. Through the regression equation of the values of MEI and ADG obtained through the experiment (Y=0.5439X+111.51, R²=0.712), the maintenance energy requirement of the goat in the growing period was estimated to be 111.51 kcal/kgBW^0.75.

• Journal of Bio-Environment Control
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• v.14 no.2
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• pp.95-105
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• 2005

This study was carried out to file up using effect and requirement of energy for environmental design data of Pleurotus eryngii growing houses. Heating and cooling Degree-Hour (D-H) were calculated and compared for. some Pleurotus eryngii growing houses of sandwich-panel (permanent) o. arch-roofed(simple) type structures modified and suggested through field survey and analysis. Also thermal resistance (R-value) was calculated for the heat insulating and covering materials of the permanent and simple-type, which were made of polyurethane or polystyrene panel and $7\~8$ layers heat conservation cover wall. The variations of heating and cooling D-H simulated for Jinju area was nearly linearly proportional to the setting inside temperatures. The variations of cooling D-H was much more sensitive than those of heating D-H. Therefore, it was expected that the variations of required energy in accordance with setting temperature or actual temperature maintained inside of the cultivation house could be estimated and also the estimated results of heating and cooling D-H could be effectively used far the verification of environmental simulation as well as for the calculation of required energy amounts. When the cultivation floor areas are all equal, panel type houses to be constructed by various combinations of materials were found to by far more effective than simple type pipe house in the aspect of energy conservation maintenance except some additional cost invested initially. And also the energy effectiveness of multi-span house compared to single span together with the prediction of energy requirement depending on the level insulated for the wall and roof area could be estimated. Additionally, structural as well as environmental optimizations are expected to be possible by calculating periodical and/or seasonal energy requirements for those various combinations of insulation level and different climate conditions, etc.

• Journal of Animal Science and Technology
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• v.45 no.3
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• pp.377-386
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• 2003

A study was conducted to evaluate seasonal variations in chemical composition of food waste (FW) and its feeding effects on growth performance and pork quality in finishing pigs. FW was collected for 1 year (6 times a month) to establish a database for use of FW as a feed ingredient. For a feeding trial (8 weeks), a total of 117 pigs ${\times}$D; 54.80$\pm$4.60kg) were used to evaluate the processing effects of FW. Treatments were: Control (a corn-soybean meal diet without FW), simple dried FW (SD) and vacuum fermented FW (VF). The gross energy, crude protein, crude fat, ash, calcium and phosphorus in FW (DM, average of 4 seasons) were 5,111kcal/kg, 22.92%, 14.31%, 15.48%, 2.7% and 1.05%, respectively. Among seasons, the energy and crude protein contents were the highest (p<0.05) in winter and summer, respectively. In lactic acid bacterial counts, there was no difference between SD and VF. Pigs fed the control diet grew faster (p<0.05) than those fed diets containing food wastes, but not feed conversion ratio. There were no differences in production traits between SD and VF. No differences were also found in dressing percentage, backfat thickness, and pork quality (color, drip loss and TBARS) among treatments. The feed cost (￦/kg body weight) was lower in pigs fed FW than those fed a control diet. In conclusion, a pelleted diet containing food waste less than 20% would reduce feed cost in finishing pigs. However, it seems that a vacuum fermentation of food waste is not necessary for diet processing.

• Journal of Nutrition and Health
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• v.54 no.1
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• pp.76-94
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• 2021

Purpose: This study was implemented to develop and validate a semi-quantitative food frequency questionnaire (SQ-FFQ) to assess the dietary intake of married migrant women in multicultural families. Methods: The SQ-FFQ consisting of 41 food items was selected based on the information of frequently consumed foods from the preliminary studies on dietary intake survey for married migrant women or a Korean Health and Nutrition Examination survey. Thirty-five subjects who visited the Multicultural Family Support Center in Seoul and Daejeon area completed their three-day diet records and SQ-FFQ 2 times. The reproducibility and relative validity of SQ-FFQ were assessed by comparing the 1st and 2nd SQ-FFQ and by comparison with the three-day diet records, respectively. Results: The reliability of SQ-FFQ, which was examined 1-2 weeks apart, showed no significant difference in the energy and macronutrient intake (carbohydrate, fat, protein), while the average intakes of vitamin A, riboflavin, calcium, and potassium were slightly higher in the 2nd than 1st SQ-FFQ. All correlation coefficients for the reliability for nutrients were statistically significant, ranging from 0.453 to 0.885. The mean intakes of energy, carbohydrate, vitamin C, thiamin, folate, vitamin B12, calcium, and sodium obtained from the SQ-FFQ were greater than those of the 3-day dietary records. The Spearman's correlation coefficient between the 2 methods was the highest for plant fat (r = 0.602; p < 0.001) and relatively higher for energy, carbohydrate, fat, and thiamin ranging from 0.512 to 0.599; and protein, riboflavin, niacin, folate ranging from 0.335 to 0.499, while no significant correlation was observed for vitamin A, C, calcium, iron, and sodium. Conclusion: The developed SQ-FFQ for married migrant women in multicultural families in this study appears to be useful for estimating the nutritional status, particularly energy, carbohydrates, fat, and vitamin B group.

• Journal of the Korean Society for Marine Environment & Energy
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• v.18 no.2
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• pp.81-93
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• 2015

The comprehensive master plan in November 2010 on Saemangeum internal development has been released, and there is a need for complementary measures related to in-situ monitoring methods in order to acquire water temperature (T) and salinity (S) data. Thus, these data are monitored and analyzed by Korea Rural Community Corporation continuously. The purposes of current study are to evaluate the distributions of seasonal T and S, sigma-t, and stratification parameter and to compare annual stratification system in 2011 and 2012. To achieve these objectives, monthly vertical changes of T, S, and sigma-t, which are reproduced by a kriging technique, have been analyzed. In summer, the temperature difference between surface and bottom layers varies from 2 to $3^{\circ}C$, and the stratification of T is considerably weak. The stratification of S occurs abruptly within depth of EL. (-)5 to EL. (-)10 m. Therefore, stratification is induced by sudden increasing of water inflow amount due to a localized downpour during the rainy season, and these stratification processes are strongly influenced by inflowing a fresh water from watersheds in estuary environment.

• Journal of the Korean association of regional geographers
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• v.23 no.1
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• pp.151-167
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• 2017

The main objective of this study was to investigate the climatic impact of $PM_{10}$ concentration on the temperature change pattern in Busan Metropolitan City(BMC), Korea during 2001~2015. Mean $PM_{10}$ concentration of BMC has gradually declined over the past 15 years. While the highest $PM_{10}$ concentration was observed in spring followed by winter, summer, and fall on average, the seasonal variations of $PM_{10}$ concentration differed from place to place within the city. Frequency analysis showed that the most frequently observed $PM_{10}$ concentration ranged from $20{\mu}g/m^3$ to $60{\mu}g/m^3$, which accounted for 64.6% of all daily observations. Overall, the west-high and east-low pattern of $PM_{10}$ concentration was relatively strong during the winter when the effect of yellow-dust events on the air quality was weak. Comparative analyses between $PM_{10}$ concentration and monthly temperature slope derived from generalized temperature curves indicated that the decreasing trend of $PM_{10}$ concentration was associated with increases of annual temperature range, and $PM_{10}$ concentration had a negative relationship with the temperature slope of warming months. Overall, $PM_{10}$ concentration had a weak correlation with the annual mean temperature, but it had a significant, positive correlation with the winter season, which had a dominant influence on the annual mean temperature. In terms of energy budget, it has been known that the change in $PM_{10}$ concentration contributes to the warming or cooling effect by affecting the radiative forcing due to the reflection and absorption of radiant energy. The correlation between $PM_{10}$ concentration and temperature changes in the study area was not seasonally and spatially consistent, and its significance was statistically limited partly due to the number of observations and the lack of potential socioeconomic factors relevant to urban air quality.