• Journal of Bio-Environment Control
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• v.27 no.1
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• pp.7-12
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• 2018

This study was conducted to determine effects of precooling and storage methods on asparagus spears' quality such as changes of fresh weight and color during simulated export distribution. Two types of precooling methods, air cooling and hydrocooling, were applied prior to packaging by comparing with no precooling as a control. Asparagus spears were packed with oxygen transmission rate (OTR) film for modified atmosphere packaging (MAP) and perforated (PF) film for a conventional packaging. All treatments were stored at $8^{\circ}C$ for 20 hours, and subsequently at $4^{\circ}C$ by final storage day, which is simulated distribution temperature condition from Yanggu, Korea to Shimonoseki, Japan. The half cooling time was 12 minutes for air cooling and 15 seconds for the hydrocooling, indicating precooling process of asparagus spears faster with the hydrocooling. Rates of respiration and ethylene production were lowest with hydrocooling. Fresh weight loss was higher, approximately 11%, at the control condition in conventional storage, compared with the MAP, less than 0.5%. Carbon dioxide and oxygen content in the MAP was in the permissible ranges for asparagus spears under recommended CA/MA conditions under both the air cooling and hydrocooling. Ethylene content in the film package was lower with the precooling treatment. Firmness of stems was lowest with the hydrocooling prior to the MAP. Visual quality, off-odor, and hue angle value were best with hydrocooling prior to the MAP. In conclusion, the combination of hydrocooling with the MAP is effective in preserving quality during the export distribution process.

• Journal of Bio-Environment Control
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• v.27 no.1
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• pp.71-79
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• 2018

This study was conducted to compare the physicochemical properties of newly developed artificial medium and conventional plug medium and to investigate the proper irrigation interval to produce the high quality tomato seedlings. The five existing artificial media (organic medium coir, mixed medium Tosilee and Q plug, and inorganic medium LC and rockwool) and four newly developed artificial medium (mixed medium TP-S1 and inorganic medium PU 14-S1, PU-7B, and PU 15-S1) were used to grow tomato 'Yegwang' with irrigation interval of one-day (14 times), two-day (7 times), and three-day (5 times) for 14 days. The pH was the significantly highest in the PU 15-S1. All growing medium measured were in the range of pH 5.17-6.90. EC was the highest in the Q plug. The initial germination rate was the highest in the PU 15-S1. The final germination rate and mean daily germination were not significantly different in all growing medium except for the PU 14-S1. Growth of tomato seedlings at 15 days after sowing was the greatest in the Q plug. At 29 days after sowing, seedlings were also the greatest in the Q plug, followed by rockwool and PU-7B. Also, growth was better in the one-day interval treatment. As a result, we confirmed the applicability of the artificial medium to tomato plug seedlings in this experiment, and seedlings were the greatest in the Q plug. Therefor, it is considered that adding nutrients to the artificial medium of the newly developed medium PU-7B, and applying the irrigation one-day interval can produces high quality tomato seedlings similar to using Q plug.

• Korean Journal of Environmental Agriculture
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• v.25 no.1
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• pp.7-13
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• 2006

Plastichouse cultivation for crops and vegetables in the winter has been widely popularized in Korea. In the vinylhouse Ultraviolet B penetration is lower than in the field, and so some problems, as plant overgrowth and outbreak of disease, occurred frequently. The effect of artificial supplement ultraviolet B $(UV-B:280{\sim}320nm)$ radiation on the physiological responses and yield of perilla (perilla frutescens) was investigated UV-B ray was radiated on perilla with the 10th leaf stage at the distance of 90, 120 and 150 cm from the plant canopy for 30 days after planting in the vinylhouse. The production of fresh perilla leaves was high in the order of plastic house, ambient+50% of supplemental UV-B, ambient ambient+100% of supplemental UV-B. Enhanced UV-B radiation affected the intensity of thirty-three proteins in 2-dimensional electrophoretic analysis of proteins and ten proteins out of them seemed to be responsive to UV-B : a protein was, ATP synthase CF1 alpha chain, down regulated and nine proteins (Chlorophyll a/b bindng protein type I, Chlorophyll a/b binding protein type II precursor, Photosystem I P700 chlorophyll a apoprotein A2, DNA recombination and repair protein recF, Galactinol synthase, S-adenosyl-L-methionine, Heat shock protein 21, Calcium-dependent protein kinase(CDPK)-like, Catalase) were up-regulated.

• Journal of the Korean Society for Marine Environment & Energy
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• v.16 no.3
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• pp.202-210
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• 2013

As incomes increase, interest in ocean leisure picks up. As a result, a lot of research and developments on hull form design and production of planing boats, mostly used for ocean leisure, are needed. Analysis in researches on resistance of planing boats shows that resistance characteristic of planing boats is different from resistance characteristic of general boats because the former is fast, and its wetted surface is very small. Using Savitsky formula widely used in the calculation of effective horse power in shipbuildingyards, and propulsion system and engine manufacturers, this study calculated total resistance of a research planing boat. Then it analyzed the flow characteristics of the planing boat through theoretical analysis and wind tunnel experiment, and computed air resistance and lift force by changes of speed and trim angle. It also compared and analyzed result of theoretical analysis and experiment of the ratio of air resistance to total resistance under variations of velocity and trim angle. When the study is used to estimate more accurate effective horse power, it is expected to remedy abuses of unnecessarily installing high-powered engine. As nature disasters due to abnormal changes of weather increase, interest in greenhouse gas grows. International Maritime Organization (IMO) legislated Energy Efficiency Design Index (EEDI) and Energy Efficiency Operational Indicator (EEOI) to reduce ship greenhouse gas emissions. But this index will be applied to over 400 tons ships, small ships, emitting more greenhouse gases than larege ships per unit power, will dodge the regulations. Thus, this study indicated a problem by calculating greenhouse gas emissions of an ocean leisure planning boat (a small ship), and suggested the need for EEDI of small ships.

• Journal of the Korean Society of Marine Environment & Safety
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• v.22 no.4
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• pp.362-371
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• 2016

The distribution patterns of Chromophoric Dissolved Organic Matter (CDOM) and the chemical characteristics of CDOM in the Seomjin river estuary were investigated in March, June and July 2012 in order to determine the spatial and temporal variability of CDOM along the salinity gradient considering the effects of mixing, nutrients and Chl a. The average CDOM values were $1.0{\pm}0.3m^{-1}$, $1.3{\pm}0.4m^{-1}$, and $1.4{\pm}0.3m^{-1}$ in March, June and July, respectively. A high concentration of CDOM (greater than $1.5m^{-1}$) was found at the head of the river which decreased towards the river mouth to as low as less than $0.5m^{-1}$. The average concentrations of CDOM increased from the dry season (March and June) to the wet season (July), and the average slope values ($S_{300-500}$), which were used as indicators of CDOM characteristics and sources, were in the range of $0.013-0.018m^{-1}$. The CDOM and $S_{300-50}$ values showed that not only the concentration of CDOM but also the chemical properties of DOM clearly changed between upstream and downstream in the Seomjin river. CDOM and FDOM showed a negative correlation with salinity ($R^2$ > 0.8), and CDOM was positively correlated with FDOM. Furthermore, the mixing pattern of CDOM was confirmed as conservative for all seasons. The main environmental factors influencing the concentration of CDOM was confirmed as conservative for all seasons. The main environmental factors influencing the concentration of CDOM were salinity (mixing) and water temperature, which meant the dilution of low CDOM seawater, was the controlling factor for the spatial distribution of CDOM. Increases in water temperature seemed to induce the production of CDOM during summer (June and July) through the biological degradation of DOM either by microbial activity or photo-degradation.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2001.04a
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• pp.98-103
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• 2001

In order to understand the characteristics of leachate at the Seokdae municipal waste landfill in the Pusan city, the correlation between leachate pollution loading and volume of gas production. concentration of gas and subsidence of ground, the characteristical methos, geochemical analyses and laboratory column tests using samples of gases, leachate and surface soil of Seokdae waste landfill area. Through the analysis of water balance, leachate flow rate and pollution loading were estimated. Geistatistical analysis of four gas components ( $O_2$, C $H_4$, $H_2$S and CO) shows the possibility of ground subsidence around the group of a site with high concentration of gas. From geochemical analyses of leachate, EC and Total-Alkalinity of ground subsidence around the group of a site with high concentration of gas. From geochemical analysis of leachate, Ec and Total-Alkalinity were increased, and Cl, Cr, Mn, Cu, Zn, Cd and Pb were decreassed comparing to the part, and the type of water quality was Na-HC $O_3$ in trilinear diagram. It shows that biodecomposition of municipal wastes continues actively. From the analysis of water balance, the total leachate flow rate is about 465.11㎥/day and pure pollution loading of Cl, Mn and Fe are estimated to 223.8kg/day, 0.2kg/day, 0.3kg/day, respectively. The laboratory column test of residual soil and landfill soil shows 0.206cm and 0.019cm for linear velocity(equation omitted), 0.234 $\textrm{cm}^2$/min and 0.018$\textrm{cm}^2$/min for diffusion coefficient ( $D_{ι}$), and 1.136cm and 0.095cm longitudinal dispersion index ($\alpha$$_{ι}$), respective]y. It demonstrates that the delay time of contamination for residual soil is shorter than that of landfill soil.

• Journal of the Korean Society of Marine Environment & Safety
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• v.26 no.1
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• pp.31-38
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• 2020

The characteristics of ship traffic routes and the long term fluctuation in marine traf ic volume of the incoming and outgoing routes of the Yeosu Gwangyang Port were analyzed using vessel traffic data from the past 22 years and a real-time vessel traffic volume survey performed for 72 hours per year, for three years, between 2015 and 2017. As of 2017, the number of vessels passing through Yeosu Gwangyang Port was about 66,000 and the total tonnage of these ships was about 804,564 thousand tons, which is a 400 % increase from the 189,906 thousand tons shipped in 1996. Specifically, the dangerous cargo volume was 140,000 thousand tons, which is a 250 % increase compared to 1996. According to the real-time vessel traffic volume survey, the average daily number of vessels was 357, and traf ic route utilization rates were 28.1 % in the Nakpo sea area, 43.8 % in the specified sea area, and the coastal area traf ic route, Dolsan coastal area, and Kumhodo sea area showed the same rate of 6.8 %. Many routes meet in the Nakpo sea area and, parallel and cross passing were frequent. Many small work vessels entered the specific sea area from the neighboring coastal area traffic route and frequently intersected the path of larger vessels. The anchorage waiting rate for cargo ships was about 24 %, and the nightly passing rate for dangerous cargo ships such as chemical vessels and tankers was about 20 %. Although the vessel traffic volume of Yeosu Gwangyang Port increases every year, the vessel traffic routes remain the same. Therefore, the risk of accidents is constantly increasing. The route conditions must be improved by dredging and expanding the available routes to reduce the high risk of ship accidents due to overlapping routes, by removing reefs, and by reinforcing navigational aids. In addition, the entry and exit time for dangerous cargo ships at high-risk ports must be strictly regulated. Advancements in the VTS system can help to actively manage the traffic of small vessels using the coastal area traffic route.

• Journal of Bio-Environment Control
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• v.12 no.2
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• pp.95-100
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• 2003

To evaluate the effect of the fertilizer concentration after flowering on growth a31d fruit setting of ornamental pepper (Capsicum annuum L.), plants were fertilized with $100\;mg{\cdot}L^{-1} of N ($EC=0.8\;dS{\cdot}m^{-1}) until flowering, and then with 0 (no fertilizer), 100, 200 or $300\;mg{\cdot}L^{-1} of N (fertilizer solution EC of 0.15, 0.8, 1.45 or $2.10\;dS{\cdot}m^{-1}, respectively) until harvest. Maximum leaf area and shoot dry mass at the end of the growing period were obtained when plants were fertilized with $200\;mg{\cdot}L^{-1} of N. Total fruit number per plant at the end of the growing period was not different when plants were fertilized with 100,200 or 300 mg{\cdot}L^{-1}of N concentration. When plants were fertilized with $200\;mg{\cdot}L^{-1} of N, the number of fruits per plant was decreased significantly as compared to 100, 200 or $300\;mg{\cdot}L^{-1} of N, whereas the percentage of red fruits at the end of the growing period was maximized. Total fruit fresh weight per plant at the end of the growing period was highest with the concentration of $200\;mg{\cdot}L^{-1} of N. The EC of the growing medium remained within 0.8 to $1.2\;dS{\cdot}m^{-1}\;2.0\;to\;3.0dS{\cdot}m^{-1}, or 3.0 to 4.5 dS{\cdot}m^{-1}when fertilizer concentrations were 100, 200 or $300\;mg{\cdot}L^{-1} of N, respectively. Throughout most of the experiment, the pH of the growing medium remained within 5.4 to 6.2, but dropped to 4.9 near the end of the experiment when fertilizer concentration was 200 or 300\;mg{\cdot}L^{-1} of N. Content of most of the nutrients In the leaf was not affected by the different fertilizer concentration. Only aluminum was significantly affected and decreased linearly with increasing fertilizer concentration. The results from this study indicated that optimal fertilizer concentration after flowering for commercial production of ornamental pepper was 100 or $200\;mg{\cdot}L^{-1} of N. At these concentrations, the EC of the growing medium remained approximately within 0.8 to 1.2 and 2 to $3\;dS{\cdot}m^{-1}, respectively. This appears to be the optimal range for vegetative growth or fruit setting of ornamental pepper plants, and indicates that ornamental pepper can be grown with a fairly wide range of fertilizer concentrations.

• Journal of Bio-Environment Control
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• v.25 no.1
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• pp.63-70
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• 2016

Water drainage from the open hydroponics often causes significant environmental pollution due to agrochemicals and loss of water and nutrients. The objectives of this study were to show the potential application of an irrigation schedule based on threshold values of volumetric substrate water content for tomato (Solanum lycopersicum L. 'Samsamgu') cultivation in a commercial hydroponic farm during spring to summer cultivation. This study was performed for minimizing effluent from coir substrate hydroponics using a frequency domain reflectometry (FDR) sensor-automated irrigation, as compared with an integrated solar-radiation (IR) and conventional timer-irrigation (TIMER) after transplanting. In results, no significant difference in daily irrigation volume was found among the treatments until 88 days after transplant (DAT). However, during the 88 to 107 DAT, the daily irrigation volume was in the order of IR (2125 mL) > TIMER (2063 mL) > FDR (1983 mL), and during the 108 to 120 DAT, it was in the order of IR (2000 mL) > TIMER (1664 mL) > FDR (1500 mL). The lowest drainage volume was observed in the FDR treatment with the order of IR (12~19%) > TIMER (4~12%) > FDR (0~7%) during the entire growing period. A lower irrigation volume in the FDR treatment after 88 DAT may be due to the sensor's detecting capacity for less water absorption by plant after completing fruit maturity with apical pruning and removal of lower leaves, while a higher irrigation volume in the IR treatment may be due to gradual increase in integrated solar-radiation amount as closer to summer season. There was no significant difference in plant growth and fruit yield among the treatments; however, a 11% and 18% of higher soluble sugar content was observed in the FDR than that of TIMER and IR treatment. respectively.

• Journal of Bio-Environment Control
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• v.19 no.1
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• pp.49-54
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• 2010

The study was conducted to compare the postharvest physiology and storability of fresh cut paprika fruits classified by normal, blossom end rot(BER), and misshapen (or knots) fruit. Some disordered paprika fruits that were produced frequently during high temperature season in highland, were sorted out to non-marketable products. These fruits are mostly wasted, but some of them may be used for fresh cut. The respiration rate of fresh cut paprika fruits was lower and ethylene production rate was higher in normal fruits than in disordered fruits, but there was no significant difference. The fresh-cut paprika fruits were stored in MAP conditions at $4^{\circ}C$, $9^{\circ}C$ and room temperature in 25 ${\mu}m$ and 50 ${\mu}m$ thickness ceramic film packaging. The fresh weight of fresh cut paprika fruits decreased below to 1.1% regardless of fruit types, but the fresh weight loss increased in thinner packaging materials and lower storage temperatures. There were not significant different carbon dioxide and oxygen contents in MAP of all fruit types, while $4^{\circ}C$ storage temperature treatment and 25 ${\mu}m$ thickness ceramic film treatment had lower carbon dioxide and higher oxygen contents. Moreover, the carbon dioxide and oxygen contents were changed rapidly at 9 days in $4^{\circ}C$ storage and at 6 days in $9^{\circ}C$ storage when the visual quality of fresh cut decreased dramatically. The ethylene concentration of packages was below 7 ${\mu}l{\cdot}l^{-1}$ in all treatments during storage, while the treatments of thinner packaging material and lower storage temperature showed lower ethylene concentration. The fresh cut of disordered fruits showed less visual quality than normal fruit treatment in both $4^{\circ}C$ and $9^{\circ}C$ storage temperatures, but there was no significant difference. The value of $4^{\circ}C$ treatment that measured 12 days in storage was higher than $9^{\circ}C$ treatment that measured 9 days in storage. The results suggest that the disordered fruits may be used to fresh cut product without any concerns that they will decreased the value of commodities more quickly than the fresh cut made of marketable paprika fruits. As the fresh cut paprika fruits stored in MAP condition, the more effective storage temperature is $4^{\circ}C$ that may have induced chilling injury a whole fruit of the paprika.