To obtain information on the indoor air quality of un-disinfected libraries used for paper records preservation, temperature, humidity, and bacterial concentration and species were investigated at five un-disinfected libraries from May to September in 2019 in the National Archives, Seoul (Nara Repository), Korea. Temperature and humidity of all the five un-disinfected libraries were well maintained at 18-22oC and 40-55% in compliance with the National Archives Paper Records Preservation Environment Standard. Bacterial concentration ranged from 2 CFU/m3 up to 280 CFU/m3 which were lower than the Korean indoor air quality standard value. A total of 68 bacterial species belonging to 33 genera were identified from indoor air of the five un-disinfected libraries. Among the 33 genera, Bacillus, Micrococcus, and Staphylococcus were the major genera. Only Micrococcus yunnanensis, Roseomonas mucosa, and Moraxella osloensis were commonly found among the five un-disinfected libraries. Bacterial species producing colonies with color on TSA media were present. Among the 68 species, Bacillus circulans and B. megaterium known to produce cellulases were found. There were also 17 species which have harmful effect on human health. The results of this study indicate that continuous monitoring of air borne bacteria is necessary in the un-disinfected libraries used for paper records preservation.

LMU(Leg Mating Unit)는 해양구조물의 플로트오버 실치에서 활용되는 장비 중 하나로 충격을 흡수하는 부분과 결합부로 구성된다. 본 연구에서는 최적설계를 통해 부유식 해양구조물의 플로트오버 설치용 LMU의 성능을 개선하여 설계 요구 조건을 만족하는 설계를 개발하였다. 초기설계는 고정식 해양구조물의 플로트오버 설치용으로 개발된 것의 제원을 참조하였으며, 초탄성재료의 거동을 표현하기 위해 Mooney-Rivlin 모델을 활용하였다. 설계민감도해석 결과를 바탕으로 중요도에 따라 설계 변수들을 선별하였고, 진화 알고리듬 기반 최적설계를 수행하였다. 최적설계 문제에서 목적함수는 LMU의 중량이며, 제약 조건은 LMU에 작용하는 최대 폰-미세스 응력과 LMU의 성능을 평가할 수 있는 반발력이다.

This study examines the effects of surrounding outdoor environmental characteristics in multi-use public facilities that are used by the susceptible population, on the concentration and distribution of indoor airborne bacteria. For this study, areas were divided into ‘factory area,’ ‘city area,’ and ‘forest area.’ The research was conducted from October 2017 to April 2018, and the selected target facilities were daycare centers, hospitals, postpartum care centers, and nursing homes for the elderly. In order to measure airborne bacteria, indoor air samples were collected using a six-stage viable particulate cascade impactor, and airborne bacteria samples were collected using MCE (Mixed cellulose esters) filters. Moreover, the outdoor airborne bacteria concentration was also measured to determine the concentration ratio (I/O ratio) of the total indoor airborne bacteria and total outdoor airborne bacteria concentrations. The results showed that the total outdoor airborne bacteria concentration was highest in the city area, with 74.2 ± 60.0 CFU/m3, and the lowest in the factory area, with 45.9 ± 35.8 CFU/m3. Furthermore, the distribution of the total outdoor airborne bacteria concentrations significantly differed across each surrounding environment (p < 0.05). On the other hand, no statistically significant difference in total indoor airborne bacteria concentrations, according to surrounding environments, was observed (p > 0.05). These findings suggest that the concentration of outdoor airborne bacteria differs across surrounding environments, unlike that of the indoor airborne bacteria.

최근 환경규제가 강화됨에 따라 액화천연가스(Liquefied Natural Gas)를 이용하여 전력을 생산해내는 신규발전설비인 부유식 LNG 발전설비(floating LNG power plant)가 개발되고 있다. 부유식 LNG 발전설비는 운용 시 증발가스가 발생하고 이를 제거하거나 회수할 수 있는 시스템의 설계가 필요하다. 그러나 해양플랜트는 해상요건에 따라 설계가 상이하고, 부유식 LNG 발전설비의 설계 전 시행착오를 줄이기 위해 지속적으로 수정이 가능한 BOG 회수시스템 공정모사 모델이 필요하다. 따라서 본 연구에서는 상용공정시뮬레이션 프로그램을 통해 부유식 LNG 발전설비에 적합한 모델을 모델링하고자 냉매사용 유무에 따라 서로 다른 BOG(Boil-Off Gas) 회수시스템을 모델링하여 BOG의 회수율과 액화점을 비교 및 분석하였으며, 그 결과 질소냉매를 사용한 BOG 회수시스템 모델을 부유식 LNG 발전설비용 BOG 회수시스템 모델로 제안하고자 한다.

Mold is one of the harmful biological pollutants in the indoor environment. To investigate how the contamination degree of mold existing in the indoor environment differs according to the characteristics of the house, the concentration of mold in the indoor air was investigated for the houses damaged by leakage or flooding. As a result of a survey of 20 houses located in Gyeonggi-do and Chungcheong-do, the concentration of mold in indoor air surprisingly exceeded more than two times the recommended indoor air quality standard of 500 CFU/m3 in all the houses investigated. The fungal concentration was high in houses with condensation and mold odors. As for the housing type, the pollution degree was higher in detached houses than in row houses. As for the type of water damage, mold contamination was higher in the leaky houses than in the flooded houses. The degree of mold concentration was 1,237 CFU/ m3 in the leaky houses. In terms of housing age, pollution was very high in houses over 20 years old. The occurrence of these measured mold concentrations was correlated at a significant level with respect to the properties of the house. This study shows that in the case of water damaged houses, careful management of mold contamination is required.

Indoor air contaminated with various pollutants commonly poses a risk to human health, and the need for installing air purifiers has been increasing. However, in commercial air purifiers pollutants-removal efficiency and durability are generally low. Since silver nano-composites are known to have catalytic oxidation and antibacterial capacities, it was anticipated to be applicable for indoor air purifiers. In this study, silver nano-composites were applied to granular activated carbon and scrubber solutions to treat a mixture of three air pollutants including toluene, formaldehyde, and bioaerosol. In the activated carbon deposited with silver nano-particles, the specific surface area decreased, resulting in a 10% loss of adsorption capacity for toluene. However, the removal efficacy of formaldehyde and bioaerosol increased by 10% due to the catalytic oxidation and antibacterial capacities. In the scrubber operation with silver nano-particles, the removal rates of formaldehyde and bioaerosol improved by 20%, while toluene removal was not observed. When the activated carbon column and the scrubber was connected in series, toluene was mainly removed by the activated carbon, and the removal rates of formaldehyde and bioaerosol increased in the presence of silver nano-particles. Consequently, for the improvement of indoor air quality, it is deemed appropriate to apply silver nano-material to indoor environments contaminated with pollutant mixtures.

신재생 에너지 자원중 풍력발전은 비약적인 기술 발전과 시장 규모가 급속하게 성장하고 있다. 최근 육상풍력발전단지의 공간적 한계, 환경 문제 등으로 인하여 설치 공간이 해상으로 이동되었고, 더욱 풍부한 풍황 조건을 가진 깊은 수심에 설치되는 부유식 해상 풍력단지의 개발이 활발하게 진행되고 있다. 해상교통관점에서 해상풍력단지의 최적위치 선정은 선박과 풍력기들의 간섭을 최소화 하고 사고 확률이 적은 곳이며, 선박 밀집도가 낮은 해역이 최적위치로 선정된다. 본 연구에서는 유전 알고리즘 기반의 계절별 1주일 기간 선박자동식별장치 데이터를 유전자 및 염색체로 구성하였다. 80개의 유전자로 구성하고 유전 알고리즘의 적합도 평가를 거쳐 부유식 해상 풍력단지의 계절별 최적위치를 선정하였다. 더 나아가 계절별 최적위치 점수를 합산하여 최종 최적위치를 선정하였다. 분석 해역에서 최적위치는 11개로 나타났으며, 해상교통관점에서 유전 알고리즘을 통한 최적위치 선정이 적용 가능함을 확인하였다.

이매패류의 부유유생은 성패 (양식자원)에 직접적인 영향을 미치고 있어, 부유유생의 출현시기 및 출현량에 관한 연구는 자연 채묘량의 증대와 인공종묘의 생산을 위해서 매우 중요하다. 이에 본 연구에서는 유전자 분석기법을 이용하여 보성 연안에서 총 21종의 이매패류 부유유생을 확인하였으며, 이 중 구마모토굴 (M. sikamea), 왜홍합 (X. atratus), 종밋 (M. senhousia), 참굴 (M. gigas), 가리맛 조개 (S. constricta), 새꼬막 (A. kagoshimensis), Kurtiella aff. bidentata 그리고 꼬막 (T. granosa)이 중요 부유유생으로 관찰되었다. 특히, 보성 연안해역의 주요 수산자원인 새꼬막 (A. kagoshimensis)과 꼬막 (T. granosa)은 각각 이매패류의 0.51~12.50% (평균 4.00%), 0.01~12.50% (평균 1.92%)의 구성비율을 차지하며 다른 이매패류보다 낮은 출현량을 보였다. 꼬막 (T. granosa)과 새꼬막 (A. kagoshimensis)의 부유유생은 6월부터 9월까지 관찰되었으나, 각각 8월 초와 8월말에 가장 높은 출현율을 보였다.

팔당호 수변지역 내 부유조류와 부착조류의 일차생산력은 부착조류의 일차생산력이 더 높게 나타났다. 따라서 수변 지역이나 하천에서는 부착조류에 의한 유기물 생성이 주요한 수생태계 에너지 공급원이 될 것으로 판단된다. 본 연구를 통해 국내에서 처음으로 지표색소의 생산속도 분석결과가 제시되었는데 향후 일차생산력을 측정하는 데 있어서 조류의 총 일차생산력으로 국한된 측정 방법을 좀 더 세분화 하여 특정 조류의 기여도 및 개별 생산력을 판단하는 데 유용하게 사용될 것으로 사료된다.

The ichthyoplanktons were sampled by Bongo net to study the distribution of the eggs and larvae in the West coastal waters of Korea during the study period (February, May, August and October of 2017). Collected fish eggs were divided into Engraulis japonicus and unidentified species. The most dominant species, Engraulis japonicus accounted for 79.52% of the total fish egg, which was followed by unidentified species (20.48%). The total of 36 taxa in fish larvae were identified based on morphological and molecular characteristics. Fish larvae were dominant by Gobiidae species. 48.30% of the total catch in abundance, which was followed by Engraulis japonicus (31.86%). These two taxa composed 80.16% of the total collected fish larvae. The seasonal diversity index of species from the collected fish larvae in the West coastal waters in 2017 was 0.625-1.883 and the evenness index was 0.380-0.865. In addition, dominance index was 0.618-0.920 and richness was 0.573-3.189.

Species composition and yearly variation of fish eggs and larval fishes were investigated from 2014 to 2016. During the study period, the fish eggs were identified as belonging to 14 taxa. The dominant species of fish eggs were Leiognathus nuchalis, Engraulis japonicus, and Konosirus punctatus. These three species accounted for 97.4% of the total number of individuals collected. The collected larval fishes were identified into 37 taxa, 22 families, and seven orders. The dominant species of larval fish were Leiognathus nuchalis, and Gobiidae fishes. These three species accounted for 85.4% of the total number of individuals collected. The diversity index of the larval fishes was the highest in 2014 (H’ = 1.60) and the lowest in 2015 (H’ = 1.15). The evenness index was the highest in 2016 (J = 0.51) and the lowest in 2015 (J = 0.39). The dominance index was the highest in 2015 (D = 83.5%) and the lowest in 2016 (D = 70.9%). In addition, the economically important species in this area were Engraulis japonicus, Konosirus punctatus, Hippocampus coronatus, Sebastes schlegelii, Acanthopagrus schlegeli, and Cynoglossus joyneri.

PE(PolyEthylene) 재료를 활용한 해상부유 구조물은 바다, 강 또는 호수의 인근이나 수역 내에 일정한 공간 부를 형성하는 부유식 구조물로, 현재는 그 용도가 소형선박 계류장뿐만 아니라 양식장, 수상 펜션, 해상부교 등에 다양하게 활용되고 있다. 이 제품군의 특징은 유연성이 뛰어나고 재활용할 수 있으며, 내약품성, 내후/내식성이 우수하다. 기존의 PE 제품군을 활용한 부유식 플랫폼은 한 개의 브래킷에 한 개의 부력관을 체결하는 단순한 구조를 구성하였고, 이로 인하여 사용자가 용도 변경 및 사용환경이 변경될 때는 적용하는데 제한이 있었다. 이에 본 연구에서는 한 개의 브래킷에 다양한 크기를 갖는 부력 관을 체결할 수 있는 구조를 개발하고, 제품의 구조 안전성을 유한요소법을 활용하여 검증하였다. 구조해석 결과, 브래킷 하단에 지름 500mm 부력관 모델에서 충돌 하중에 대해 최대값을 나타내었으나, 허용기준을 만족하였다. 본 연구 결과를 기반으로 하여, 향후 다양한 형태의 부유체 플랫폼에 대한 구조 안전성 평가에 관한 연구가 가능하며, 관련 평가 기준에 대한 정립이 필요하다.