This study analyzed the flow inside floating seedling equipment for Scapharca subcrenata. Due to the aging society of fishing villages, it is impossible to continuously input the labor force. Therefore, it is necessary to improve efficiency. Scapharca subcrenata has high per capita consumption. It serves as an important aquatic food resource. Scapharca subcrenata culture tends to be highly dependent on the natural environment. Production of Scapharca subcrenata is difficult to predict with low stability. In the past, manpower directly installed bamboo nets in mudflats. The seedling equipment devised in this study is a floating type and can be freely moved on the sea according to the prediction of Scapharca subcrenata generation. The flow around the floating seedling equipment was analyzed by numerical analysis. The physical phenomena of the flow around the net inside the floating seedling equipment were visualized. As a result, the space between the floating seedling equipment and the bottom net and the space between the net groups showed a lower flow rate than the inlet flow rate. It is expected that the low flow rate of the floating seedling equipment will have a positive effect on the attachment of Scapharca subcrenata.

일반적으로 부유식 해상풍력발전 에너지의 수급성과 효율을 극대화하기 위해서는 하부구조물의 파랑 감쇠로 인한 운동을 저 감시키는 것이 중요하다. 선행 연구들에 따르면 파도 중 하부구조물에 설치된 감쇠판에 의해서 발생한 와류점성으로 인해 운동 응답이 감소되는 것으로 나타났다. 본 연구에서는 5MW급 반잠수식 OC5 플랫폼과 감쇠판이 부착된 두가지 플랫폼을 설계하고, 와류점성으로 인 한 운동저감효과를 확인하기 위해 자유감쇠실험과 수치계산을 수행하였다. 모형시험 결과로 낙하 높이를 30 mm, 40 mm, 50 mm에서의 상하 자유감쇠실험을 수행하였을 때 OC5 플랫폼 대비 두 가지의 형태의 감쇠판이 부착된 플랫폼이 상대적으로 운동감쇠성능이 향상되었다. 모형시험과 수치계산 결과에서 형상화한 감쇠판 모델(KSNU Plate 1, KSNU Plate 2)들이 각각 OC5 대비 상하운동 진폭이 1.1배, 1.3배 각각 감소했으며, KSNU Plate 2 플랫폼은 KSNU Plate 1 플랫폼보다 OC5 대비 약 2배 감쇠성능이 좋아진 것으로 나타났다. 본 연구에서는 감쇠 판의 면적과 와류점성이 상하동요의 감쇠율과 밀접한 관련을 보여준다.

This study was carried out to investigate how airborne bacteria are distributed under different temperature conditions while cultivating oyster mushrooms by setting the indoor temperature of the cultivation room to 10°C, 15°C, 20°C, 25°C, and 30°C. The surveys were conducted in April and May, respectively. Airborne bacterial concentrations were distributed in the range of 1.61 × 102 ~ 3.67 × 102 CFU/m3 in April and 5.47 × 102 ~ 7 × 103 CFU/ m3 in May. In May, the indoor air quality maintenance standard (8.0 × 102 CFU/m3) was exceeded in the 10°C, 20°C, and 25°C cultivation rooms. Bacterial concentrations increased significantly in May compared to April. Bacterial concentrations were different between the cultivation rooms at different temperatures. The difference was more pronounced in May than in April. A total of 15 genera and 20 species were isolated from the indoor air of the oyster mushroom cultivation rooms. Overall, it was most abundant in Actinomycetia. Among the species identified, Agrobacterium radiobacter, Brevundimonas vesicularis, Kocuria palustris, K. salsicia, Lysinibacillus fusiformis, and Sphingobacterium siyangense are known to affect human health. This is the first report of airborne bacteria in cultivation rooms at different temperatures used for oyster mushroom cultivation. The results of this study are expected to be used as basic data to understand the indoor environment of thermophilic mushroom cultivation facilities.

본 논문에서는 해상 위험유해물질(Hazardous Noxious Substances, HNS) 사고의 효과적인 대응을 위해 개발된 부유식 무인이동체 기반 광역탐지 및 모니터링 시스템의 운용 시나리오 설계와 실험 검증 내용을 보인다. 광역탐지 및 모니터링 시스템은 장시간 운용이 가 능하되 제한적 이동이 가능한 무계류형 부이 형태를 갖는 부유식 무인이동체 플랫폼을 기반으로 개발되었으며 임무 수행에 필요한 열화 상 카메라, 레이더, 부유 및 대기 HNS의 탐지를 위한 센서가 탑재되었다. 실험 검증 과정에서는 탐지 센서 성능을 야외 환경에서 실험적 으로 검증하기 위해 이동식 가스 유출 시스템(Portable Gas-exposure System, PGS)을 추가로 설치하였다. 무인 시스템의 원격 및 자율 운용을 위해 전체 운용 소프트웨어는 로봇운영체제(Robot Operating System, ROS) 프레임워크를 기반으로 통합되었다. 내수면 및 실해역에서의 실 험을 통해 개발된 시스템의 운용 및 활용 가능성을 실험적으로 검증하였다.

To provide information needed for managing fish resources and protecting the ecosystem of Cheonsu Bay, bimonthly variations in species composition and abundance of fish eggs and larvae were investigated. The samples were collected by using bongo net at three different stations from February 2020 to December 2021. Fish eggs were divided into Engrualis japonicus and unidentified eggs, of which Engragulis japonicus accounted for 85.6% of the total eggs collected. A total of 21 species representing 17 families and 6 orders were collected. The three dominant species were Gobiidae spp, Thryssa hamiltonii and E. japonicus and these three species accounted for 74.1% in the total number of individuals. The number of species was highest in August, 2020 and lowest in February, 2020 and 2021; the number of individuals was highest in August, 2020 and lowest in February, 2020. Temporal changes in the abundances of pelagic eggs and larval fishes corresponded with temperature.

국내에서 일어난 해양사고 발생 현황을 보면 평균적으로 약 8.5% 정도 사고 발생건수가 증가하는 추세를 보이고 있으며, 부선, 예인선, 유·도선 및 부유식해상구조물에서도 동일한 경향을 나타내고 있다. 본 연구에서는 국내 부유식해상구조물을 종류에 따라 분류하 고, 선박안전법, 어선법, 낚시 관리 및 육성법 등 관련 국내법을 참고하여 부유식 구조물의 종류에 따른 기준체계와 적용 범위를 검토하고 자 하였다. 아울러 해상 환경을 고려하여 국내 규정을 적용함에 있어 구조적으로 취약한 부분과 안전상의 사각지대에 놓인 위험 요소를 조기 발굴하고, 발굴된 위험 요소에 대해서 효과적인 개선 방안을 도출하고자 하였다.

해상공사에서 발생하는 부유사는 해수의 탁도를 증가시키고 광량을 감소시켜 해양생물에 악영향을 미치므로 해양환경영향평 가에서 중요한 요소이다. 하지만 평가에 적용되는 인자에 대한 공식적인 자료의 부족과 평가자의 능력에 따라 그 영향이 달리 평가되고 있다. 따라서 본 연구에서는 해역이용영향평가센터에서 검토한 3년간(2012–2014)의 매립, 준설, 외곽시설물 설치 등 총 58건 사업에 대한 부유사 확산 평가에 대한 실태를 진단하고 개선방안을 제시하였다. 개선방안 제시를 위해 4가지의 평가지표(격자체계의 적정성, 원단위의 적정성, 대표입경 및 침강속도의 적정성)를 적용하였다. 각 항목별 신뢰도에 평균점수 분석결과, 격자체계는 25점, 원단위는 60점, 대표입 경은 34점 그리고 침강속도는 17점으로 평가항목에 대한 개선방안이 필요한 것으로 나타났다. 본 연구에서는 부유사 확산 평가상태에 대 한 진단 및 신뢰도 평가 결과를 활용하여 부유사 확산예측에 대한 개선방안을 제안하였다. 먼저, 부유사 발생원단위 및 대표입경별 침강 속도에 대한 공신력 있는 값이 가이드라인을 통해 제공해야 한다. 그리고 실무에선 신뢰성 향상을 위해 격자체계의 적정성과 결과의 검 증을 철저히 해야 한다.

Suspended solids play an important role in the growth and survival of aquatic organisms. The marine zooplankton species tested in this study were Tigriopus west (Copepoda) and Haustorioides koreanus (Amphipoda) sampled from the intertidal zone, including Artemia nauplii (Branchiopoda) hatched from cysts. The study design included six concentrations (0, 50, 100, 250, 500, and 1,000 mg L-1) of the suspended test particles assayed in triplicate. Experimental cultures in 500 mL-round polycarbonate bottles were subsampled after 96 h to count dead zooplankton. The culture bottles were agitated at 4 RPM on a rotating wheel at 23°C and 30 PSU. The survival rates of Artemia nauplii and T. west were not affected by suspended solid concentrations higher than 50.0 mg L-1, whereas the survival rate of H. koreanus decreased with increasing concentrations (p<0.05). In conclusion, H. koreanus and T. west, which were continuously exposed to suspended solid concentrations higher than 50.0 mg L-1, were affected by low-intensity ecological stress. However, in the case of H. koreanus, a concentration of 50.0 mg L-1 may be considered to be the limit of tolerance to suspended solids, suggesting that the number of individuals who eventually die will increase if continuously exposed.

The changes in COD, TOC, T-P, and T-N concentrations were investigated for 2 years in the constructed wetland of Sookcheon, which was installed to improve the water quality of Daecheong reservoir in South Korea. In order to evaluate the pollution level of sediments in the wetland, settling velocity of particulate material (4 times) and sedimet material contents (6 times) were measured. COD and TOC concentrations increased slightly as they passed through wetlands, and T-N and T-P concentration tended to decrease. The material content (COD, T-P, T-N) of aquatic plants was higher in floating-leaved and free-floating macrophytes than emergent macrophytes. As a result of measuring the sedimentation rate of suspended materials, most of the suspended materials introduced into constructed wetlands were sedimented at a rapid rate in the first sedimentation site. In addition, sediment pollution of T-P and T-N in constructed wetland was in severe pollution. The sediments containing a large amount of T-P and T-N were eluted by physical and chemical environmental changes, which is likely to act as internal pollution sources in wetlands.

Distribution of airborne bacteria in the entire regions of South Korea was investigated and analyzed by region and type of multi-use facilities. At first, 10 public facilities were selected including general restaurant, retail store, public transport, retail market, apartment house, underground parking lot, financial institution, business facility, educational institution, and public toilet, which are located at the regions such as Seoul, Busan, Daejeon, Gwangju, Gyeonggi, Jeju, and Gangwon. The regional distribution of the floating bacteria was identified that Micrococcus sp. was highly prevalent in Seoul (21.5 percent). In Daejeon, Bacillus sp. was highly prevalent (12.4 percent). In Busan, Micrococcus sp. was highly prevalent (22.8 percent). In Gwangju, Bacillus sp. was 9.35%. In Gyeonggi, Micrococcus sp. was 13.7%, and in Gwangju and Jeju, Micrococcus sp. was 11.2 percent and 92%. All in all, Micrococcus sp. and Bacillus sp. were highly detected throughout the entire region and multi-use facilities. Next, whether or not these airborne bacteria could influence the health of people was examined using HaCat human skin cell line which is human epithermal Karatinocytes related to allergic dermatitis. Among these isolated microorganisms, the HaCat cell proliferation was decreased by Arthrobacter sp., Bacillus sp., Brachybacterium sp., Brevundimonas sp., Kocuria sp., Mammaliicoccus sp., Norcardia sp., Prestia sp., Phychrobacillus sp., and Rhodococcus sp., while it was affected by the other bacteria. Therefore, these results have suggested that the airborne floating bacteria could be considered as the marker for the environmental risk management against atopic dermatitis, and it is needed for controlling the bacteria number that suppressed the proliferation of HaCat cells.

This study measured the suspended fungal concentration in indoor multiple facilities nationwide. The regions were selected as representative cities by region: Seoul, Gyeonggi (Incheon), Gangwon, Gwangju, Daejeon, and Busan. A total of 2028 regional comparisons, including department stores, schools, public toilets, libraries, and banks, subway, sports facilities and comparative analysis were conducted for each multi-use facility industry. Among the nationwide, Among the regions, the average concentration of floating mold in indoor multi-use facilities was the lowest in Busan at 394.67 CFU/m3, followed by Gyeonggi and Incheon 487.90 CFU/m3, Seoul 542.84 CFU/m3, Daejeon 809.30 CFU/m3, Gangwon 1,145.22 CFU/m3, Gwangju was 1,371.10 CFU/m3 in the order. Busan was the lowest, and Gangwon was the highest. The reason that Busan, which has a high average temperature and population density, shows a lower mold concentration than Gangwon, is that floating mold in the indoor air is not affected by the external atmospheric environment, population density, and number of facility users. Although it cannot be said that there is no influence of the atmospheric environment, it was found that the indoor environment has different characteristics from the outdoor environment. The importance of air quality management has been confirmed, and further, it is necessary to subdivide the management standards by region and multi-use facilities, and the management standards need to be converted to maintenance rather than recommendations.

A field study was conducted to reduce airborne bacteria by supplying active ions to indoor spaces used by vulnerable human groups spending substantial amounts of time in places such as schools and hospitals. In an experiment conducted during school hours (8:00-15:00), the average number of airborne bacteria in classrooms was 345.53 CFU/m3 or more without active ions. However, ion supply reduced the airborne bacteria to an average of 113.23 CFU/m3, indicating an efficiency of 61.61%. As a result of tests in 33 rooms used for surgery in small and middle sized hospitals, ion supply for 2 to 4 hours reduced the average airborne bacteria concentration from 243.88 CFU/m3 to 104.34 CFU/m3, representing a 41.53% reduction. A laboratory test to confirm the ion activity has shown that the mortality rate of E. coli used as a test bacterium increased with exposure time to ions. The initial colony number of E. coli was 251 CFU, but decreased to 4 CFU after 60 minutes of exposure to active ions. Therefore, it was confirmed that the supply of active ions can contribute to the control of airborne bacteria in the indoor environment of schools, hospitals and other public facilities.

As modern society has emerged and developed, the subway has established itself as a representative means of transportation in the city due to its speed, accuracy, and accessibility. According to the Indoor Air Quality Management Act, underground stations have established and managed the maintenance and recommendation standards for PM10, PM2.5, CO2, CO, HCHO, NO2, Rn, VOCs However, th the standards for airborne mold has not been applied for subway stations even though management for the health effect of exposure to mold is necessay. In this study, the correlation with major contributing factors was analyzed by measuring the concentration of airborne molds in the indoor air of underground stations and through literature research. It was confirmed that there was a correlation between the concentration of airborne molds in subway stations and the major contributing factors. As a result of the analysis, it was found that the concentration of airborne molds became higher as the location of the platform became deeper underground, during periods of congestion, and especially in summer. There was no significant correlation with the year of construction. Our findings indicate that appropriate management measures should be devised in response to such contributing factors.