• Journal of the Korea Organic Resources Recycling Association
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• v.25 no.3
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• pp.91-98
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• 2017

The purpose of this study is to provide a design and operation technical guideline for meeting the appropriate design criteria to bio-gasification facilities treating organic wastes. 9 anaerobic digestion facilities which is normally operated during the field survey and 14 livestock manure farms were selected for precision investigation. the physicochemical analysis was performed on the moisture and organic contents, nutrients composition (carbohydrate, fat, protein), volatile fatty acids (VFAs), and nitrogen, etc. Volatile solids (VS) of organic wastes brought into the bio-gasification facilities were 2.81 % (animal manure only) and 5.92 % (animal manure+food waste), respectively. Total solids (TS) reults of samples from livestock farms were 5.6 % in piglets and 11~13 % in other kinds of breeding pigs. The actual methane yield based on nutrients contents was estimated to $0.36Sm^3CH_4/kgVS$ which is equivalent to 72 % of theoretical methane yield value. The optimum mixing ratio depending on the effect of the combined bio-gasification was obtained through the continuous stirred-tank reactor (CSTR) which is operated at different mixing ratio of swine manure and food waste leachate. The range of swine manure and food waste leachate from 60:40 to 40:60 were adequate to the appropriate conditions of anaerobic digestion; less than 100 gTS/, more than alkalinity of 1 gCaCO3/L, C/N ratio 12.0~30.0, etc.

• Journal of Wetlands Research
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• v.17 no.1
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• pp.26-37
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• 2015

Halophyte distribution pattern and area in the Suncheon-bay and Beolgyo estuary coastal wetlands were analyzed using KOMPSAT-2 landsat images were taken in 2008 and 2009, and field investigations were fulfilled for confirming the precise boundaries of individual halophyte areas. The salt-marsh vegetation in those areas can be classified mainly into two dominant communities: Suaeda japonica-dominant and Phragmites communis-dominant communities. In order to identify sedimentary characteristics, tidal-flat surface leveling and sedimentary facies analysis had been conducted. The sedimentary facies of marsh area are mostly silty clayey and clay facies with a little seasonal change and its slope is very gentle (0.0007~0.002 in gradient). Phragmites communis and Suaeda japonica communities were distributed in the mud-flat zone between 0.7 m and 1.8 m higher than MSL (mean sea level): zone of 1.1~1.8 m in the former and zone of 0.7~1.3 m in the latter. In the Suncheon-bay estuarine wetland, on the basis of 2009 distribution, Phragmites communis-dominant and Suaeda japonica-dominant communities are about $0.79km^2$ and $0.22km^2$ in distribution area, respectively. On the other hand, Bulgyo estuarine marsh shows that the distribution areas of Phragmites communis-dominant and Suaeda japonica-dominant communities are about $0.31km^2$ and 0.031km2 in distribution area, respectively. Individual 105 and 60 dominant community areas and their distribution patterns can be well defined and indicated in the Suncheon-bay and Bulgyo estuarine marshes, respectively. The distribution pattern and area of hylophyte communities analyzed in this study based on 2008/2009 satellite images would be valuable as a base of future monitoring of salt-marsh related studies in the study area which is the most important salt-marsh research site in Korea.

• The Korean Journal of Nuclear Medicine Technology
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• v.13 no.3
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• pp.123-131
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• 2009

Purpose: We tested a sample of nuclear medicine workers at Korean healthcare institutions for internal contamination with radioactive isotopes, measuring concentrations and evaluating doses of individual exposure. Materials and Methods: The detection and measurement was performed on urine samples collected from 25 nuclear medicine workers at three large hospitals located in Seoul. Urine samples were collected once a week, 100~200 mL samples were gathered up to 6~10 times weekly. A high-purity germanium detector was used to measure gamma radiations in urine samples for the presence of radioactive isotopes. Based on the detection results, we estimated the amounts of intake and committed effective doses using IMBA software. In cases where committed effective doses could not be adequately evaluated with IMBA software, we estimated individual committed effective doses for radionuclides with a very short half life such as $^{99m}Tc$ and $^{123}I$, using the methods recommended by International Atomic Energy Agency. Results: Radionuclides detected through the analysis of urine samples included $^{99m}Tc$, $^{123}I$, $^{131}I$ and $^{201}Tl$, as well as $^{18}F$, a nuclide used in Positron Emission Tomography examinations. The committed effective doses, calculated based on the radionuclide concentrations in urine samples, ranged from 0 to 5 mSv, but were, in the majority of cases, less than 1 mSv. The committed effective dose exceeded 1 mSv in three of the samples, and all three were workers directly handling radioactive sources. No nurses were found to have a committed effective dose in excess of 1 mSv. Conclusions: To improve the accuracy of results, it may be necessary to conduct a long-term study, performed over a time span wide enough to allow the clear determination of the influence of seasonal factors. A larger sample should also help increase the reliability of results. However, as most Korean nuclear medicine workers are currently not necessary to monitored routinely for internal contamination with radionuclides. Notwithstanding, a continuous effort is recommended to reduce any unnecessary exposure to radioactive substances, even if in inconsequential amounts, by regularly surveying workplace environments and frequently monitoring atmospheric concentrations of radionuclides.

• Journal of the Korean Society for Marine Environment & Energy
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• v.11 no.1
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• pp.24-34
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• 2008

To mitigate the climate change and global warming, various technologies have been internationally proposed for reducing greenhouse gas emissions. Especially, in recent, carbon dioxide capture and storage (CCS) technology is regarded as one of the most promising emission reduction options that $CO_2$ be captured from major point sources (eg., power plant) and transported for storage into the marine geological structure such as deep sea saline aquifer. The purpose of this paper is to review the latest progress on the development of technologies for $CO_2$ storage in marine geological structure and its perspective in republic of Korea. To develop the technologies for $CO_2$ storage in marine geological structure, we carried out relevant R&D project, which cover the initial survey of potentially suitable marine geological structure fur $CO_2$ storage site and monitoring of the stored $CO_2$ behavior, basic design for $CO_2$ transport and storage process including onshore/offshore plant and assessment of potential environmental risk related to $CO_2$ storage in geological structure in republic of Korea. By using the results of the present researches, we can contribute to understanding not only how commercial scale (about 1 $MtCO_2$) deployment of $CO_2$ storage in the marine geological structure of East Sea, Korea, is realized but also how more reliable and safe CCS is achieved. The present study also suggests that it is possible to reduce environmental cost (about 2 trillion Won per year) with developed technology for $CO_2$ storage in marine geological structure until 2050.

• Journal of Bio-Environment Control
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• v.23 no.2
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• pp.158-166
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• 2014

This experiment has investigated suitable methods to improve precision water content monitoring of coconut coir substrates to control irrigation by frequency domain reflectometry(FDR) sensors. Specifically, water content changes and variations were observed at different sensing distances and positions from the irrigation dripper location, and different spaces between the FDR sensors with or without noise filters. Commercial coconut coir substrates containing different ratios of dust and chips(10:0, 7:3, 5:5, 3:7) were used. On the upper side and the side of the substrates, a FDR sensor was used at 5, 10, 20, 30cm distances respectively from the irrigation dripper point, and water content was measured by time after the irrigation. In the glass beads, sensors were installed with or without noise filtering. Closer sensing distance had a higher water content increasing rate, regardless of different coir substrate ratios. There were no differencies of water content increasing rates in 10:0 and 3:7 substrates between the upper side and the side. Whereas, 7:3 and 5:5 substrates showed higher increasing rates on the upper side measurements. Substrates with higher ratios of chip(3:7) had lower increasing rates than others. And, with noise filters, the exatitude of measurement was improved because the variation and deviation were reduced. Therefore, in coconut coir with FDR sensors, an efficient water content measurment to control irrigations can be achieved by installing sensors closer to an irrigation point and upper side of substrates with noise filters.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.17 no.2
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• pp.45-58
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• 2012

For the development of reference values and evaluation of water quality in various environmental conditions, we divided the coastal region around Korean peninsular into 5 distinctive ecological regions based on the influence of surface current, depth, tidal range, turbidity, and climate condition. We used national marine environment monitoring data collected by National Fisheries Research & Development Institute(NFRDI) from 2000-2009. For the reference values, we used maximum seasonal mean from 2000 to 2007 for DIN, DIP, and chlorophyll-a and minimum seasonal mean for secchi depth measured at stations without the influence of river runoff in each ecological regions. For the reference value of bottom dissolved oxygen saturation, we used minimum mean value of 90% calculated from minimal riverine influence stations of whole regions. We calculated enrichment score for each assessment criteria. The enrichment score of DIN, DIP, and Chlorophyll-a was 1 (=< reference value), 2 (< 110% of reference value), 3 (< 125% of reference value), 4 (< 150% of reference value), and 5 (> 150% of reference value). The enrichment score of DO saturation and Secchi depth was 1 (> reference value), 2 (> 90% of reference value), 3 (>75 % of reference value), 4 (> 50% of reference value), and 5 (< 50% of reference value). We calculated water quality index using weighted linear combination of five enrichment score for the comparison of whole regions. From the water quality index distribution calculated from all stations between 2000 and 2007 period, we classified into 5 grade based on the standard deviation calculated from total water quality index. We assigned grade very good(I), good(II), moderate(III), bad(IV), and very bad(V) when the water quality index was less than 23, minimum + 1 sd, +2 sd, +3 sd, and grater than minium+ 3 sd, respectively.

• Pediatric Infection and Vaccine
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• v.23 no.3
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• pp.202-208
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• 2016

Purpose: Rotavirus vaccine (RV) was introduced in Korea since 2007, and intussusception (IS) remains an important safety concern. This study investigated the trend of IS occurrence related to RV as well as the temporal relevance between vaccination and IS in children. Methods: We collected data of the patient aged ${\leq}18$ years with IS admitted to Gachon University Gil Medical Center, 2003 to 2015. For the patients that have occurred since 2008, the immunization records of RV were collected. The proportion of cases <1 year was calculated by the year and the temporal relationship between vaccination and IS occurrence was analyzed. Results: A total of 696 IS cases were noted. The cases <1 year were 30.7% (214/696). Although the incidence of all IS has increased over the 13-year period (from 74.1 in 2003 to 89.5 in 2015, linear by linear association, P=0.003), the incidence of IS <1 year has not increased (from 56.9 in 2003 to 53.3 in 2015, P=0.910), and the proportion of cases <1 year has decreased (from 35.4 in 2003 to 18.8 in 2015, P=0.000). Of 128 cases <1 year since 2008, 53.9% received RV. In the vaccinated group, 10 cases of IS occurred within 30 days, and eight cases did within 31 to 60 days. Numbers of IS after first, second, and third dose were three, 10, and five cases, respectively. Conclusions: Occurrence of IS in children <1 year of age did not increase since the introduction of RV. Further monitoring is essential for evaluation of vaccine safety.

• Pediatric Infection and Vaccine
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• v.16 no.2
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• pp.131-141
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• 2009

Purpose : In February 2007, an outbreak of methicillin-resistant Staphylococcus aureus (MRSA) skin and soft tissue infections occurred in two newborns in the neonatal unit of Sahmyook Seoul Hospital. We performed this study to investigate the characteristics of MRSA nasal carriage among neonatal unit staffs and the effective infection control measures. Methods : Nasal swab specimens were obtained from the neonatal unit staff for the presence of MRSA. MRSA-colonized staffs were offered decolonization therapy with oral trimethoprim-sulfamethoxazole or 2% mupirocin ointment. Every 2-4months after decolonizaton, repeat nasal swab specimens were obtained. Also, samples from the neonatal unit environment and room air were collected. Results : Successful decolonization was achieved in 92% of the cases in 2 weeks after decolonization therapy, but most of the staffs were recolonized after several months. The nature of antibiotic susceptibility was changed from multi-drugsusceptible to multi-drug-resistant. The most frequently contaminated objects were dressing carts, computer keyboards, bassinets and washbowls. In environmental cultures using the settle microbe count method, the colony counts were decreased significantly at the last study period compared with the first study period in the neonatal room, breastfeeding room, service room, and dressing room (P <0.05). Conclusion : Effective control of sustained MRSA transmission within an institution may require prompt identification, treatment, and monitoring of colonized and/or infected staffs. However, nasal decolonization therapy may induce multi-drugresistant MRSA infection and had no effect on decreasing the MRSA nasal carriage rate in our study. Other factors might be more important, such as improving staff education, increasing hand hygiene practices, and environmental sterilization for controlling MRSA infections.

• Journal of Embryo Transfer
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• v.21 no.3
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• pp.217-223
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• 2006

This study was carried out principally to obtain the basic data for the improvement of the reproductive performance and production using plasma progesterone assay and ultrasonography in dairy cow. The results obtained from this studies were as follows. The results of reproductive examination in 85,983 cows were ovarian diseases 40,399 (47.0%), uterine diseases 11,912 (13.9%), pregnancy or pregnant failures 26,587 (30.9%), adhesion of reproductive tracts 172 (0.2%), freemartin 8 (0.01%), and others 6,905 (8.3%), respectively. The treatment status of reproductive dysfunction in 30,241 cows were silent heat or error of estrus detection 14,909 (49.3%), follicular cysts 3,750 (12.4%), luteal cysts 907 (3.0%), inactive ovaries 665 (2.2%), granulosa cell tumor of ovary 3 (0.01%) and endometritis 6,986 (23.1%), respectively. The indices of reproductive efficiency after the periodical examination of reproductive status were as follows; the mean intercalving inteual was reduced from 475 days at the first examination to 381 days at the last examination of reproductive status, the mean interval calving to conception was reduced from 186 to 98 days, the mean interval calving to first service was reduced from 106 to 66 days, the cows showing heat by 60 days postpartum were increased from 32 to 90%, the mean conception rate to first service was increased from 42 to 64%, and the mean service per conception was reduced from 2.6 to 1.8 times, respectively.

• Korean journal of applied entomology
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• v.54 no.4
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• pp.401-407
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• 2015

This study describes the development of a method for monitoring Aphis gossypii in greenhouse cucumber fields that was used during 2013 and 2014. The dispersion pattern of A. gossypii was determined by commonly used methods: Taylor's power law (TPL) and Iwao's patchiness regression (IPR). The sample unit was determined by linear regression analysis between mean density of sample unit versus whole plant. The optimum sample unit for different plant growth stages was two leaves (median and the lowest + 1 leaf) when the total number of leaves was less than nine, and three leaves (4th, 7th from canopy, and the lowest +1 leaf) when the total number of leaves was greater than nine. A. gossypii showed an aggregated distribution pattern, as the slopes of both TPL and IPR lines were greater than 1. TPL provided a better description of the mean-variance relationship than did IPR. The slopes and intercepts of TPL and IPR from leaf samples did not differ between the surveyed years. Fixed precision levels (D) for a sequential sampling plan were developed using Green's and Kuno's equations based on the number of aphid in a leaf sample. Green's method was more efficient than Kuno's to stop sampling. The number of samples needed to estimate the density of A. gossypii increased at higher D levels and lower mean densities. The cumulative number of aphids needed to stop sampling increased at higher D levels and with fewer plants sampled. Thus to estimate 10 aphids per leaf, 13 plants needed to be sampled, and the cumulative number of aphids to stop sampling was 131.