본 연구에서는 강화되는 황산화물 및 입자상물질의 배출규제를 만족시키기 위한 후처리장치로 습식전기집진기에 대한 실험적 연구를 수행하였다. 실험을 위해 선박용 중유(HFO, 황함유량 약 2.1%)를 연료로 사용하는 선박용 4행정 디젤엔진(STX-MAN B&W)을 활용 하였으며, 연돌에 설치된 습식전기집진기 입/출구에서 측정을 실시하였다. 미세먼지 측정을 위해서는 광학식 계측기(OPA-102) 및 중량농 도측정방식(Method 5 Isokinetic Train)을 이용하였으며, 황산화물 계측을 위해서는 FT-IR(DX-4000)을 사용하였다. 엔진부하는 50%, 75%, 100%로 변화시키면서 실험을 실시하였다. 실험 결과로, 엔진부하가 50%에서 100%로 변화함에 따라 미세먼지 저감 효율은 모든 부하 조건에서 94~98% 정도의 높은 저감 효율을 나타내었다. 추가적으로 습식전기집진기 퀜칭존에서 배기가스의 온도를 낮추는 과정 중 세정액에 의한 이산화황(SO2) 저감을 확인할 수 있었으며, 저감율은 엔진부하에 따라 55%~81%로 확인되었다.

본 연구에서는 CO2 가스 배출 저감 및 선박 폐열 회수 증대를 목적으로 선박 배기로 버려지는 폐열을 전기로 변환하는 ORC(Organic Rankine Cycle) 발전에 대해 시뮬레이션을 통한 냉매별 효율을 보여주고 있다. 상대적으로 고온인 배기가스의 폐열과 상대적으로 저온인 냉각해수를 이용하여 Aspen HYSYS 11을 이용하여 시뮬레이션을 수행하였다. 해수냉각 ORC 발전시스템의 시뮬레이션 결과, 작동유체 효율은 R717 냉매가 2.86 %로 가장 높았고, 다음 순으로 R152a, R134a, R143a, R125a로 나타났다.

Stainless steel, a type of steel used for high-temperature parts, may cause damage when exposed to high temperatures, requiring additional coatings. In particular, the Cr2O3 product layer is unstable at 1000oC and higher temperatures; therefore, it is necessary to improve the oxidation resistance. In this study, an aluminide (Fe2Al5 and FeAl3) coating layer was formed on the surface of STS 630 specimens through Al diffusion coatings from 500oC to 700oC for up to 25 h. Because the coating layers of Fe2Al5 and FeAl3 could not withstand temperatures above 1200oC, an Al2O3 coating layer is deposited on the surface through static oxidation treatment at 500oC for 10 h. To confirm the ablation resistance of the resulting coating layer, dynamic flame exposure tests were conducted at 1350oC for 5–15 min. Excellent oxidation resistance is observed in the coated base material beneath the aluminide layer. The conditions of the flame tests and coating are discussed in terms of microstructural variations.

본 연구에서는, 주위 산도나 근적외선과 같은 외부에서 주어지는 자극에 의하여 내부 탑재 약물의 방출을 조절할 수 있는, 자극 응답성 키토산(Cs) 하이드로겔를 합성하고 그것의 특성과 성능을 조사하였다. 우선 Cs와 carbic anhydride의 개 환반응에 의하여 노르보닐(Nb) 작용기가 도입된 Cs 유도체(Cs-Nb) 를 합성하였으며, methyltetrazine-amine과 selenolactone의 반응에 의하여 테트라진 (Tz) 작용기가 양 말단에 도입된 가교제(Se-Tz)를 합성하였다. Cs-Se 하 이드로겔은 CS-Nb와 Se-Tz 사이의 클릭반응에 의하여 빠르게 형성할 수 있었으며, Nb/Tz 반응 몰비 변화로서 가교도를 조절하였다. 하이드로겔의 가교도와 용액의 산도가 낮을수록 하이드로겔의 팽윤도가 높아졌으며, 하이드로겔의 내부구조가 다공성을 가짐을 SEM 단면 분석 결과 확인할 수 있었다. Ciprofloxacin hydrochloride monohydrate 약물을 탑재한 하이드로겔은 pH 5.2의 PBS용액에서 pH 3.7에 비하여 높은 약물 방출을 나타내었다. 또한 근적외선 조사에 의하여 약물 방출을 빠르게 유도할 수 있었다.

PURPOSES : The purpose of this study is to evaluate the road design elements affecting the lateral driving safety under high-speed driving conditions with a speed limit of 140 km/h and to derive useful implications to design of safer roads. METHODS : A full-scale driving simulator was used to evaluate the various design scenarios. Different regression techniques and a random forest method were adopted to conduct comprehensive comparisons among the simulation scenarios. The relationships between the safety indicators, including the frequency of the lane departures and the standard deviation of the lateral acceleration, and the design elements were explored in terms of lateral driving safety. RESULTS : The length of the combined alignment was found to be a significant factor affecting the lateral driving safety based on the analysis of the frequency of lane departures. Regarding the standard deviation of the lateral acceleration, it was identified that the length of the horizontal curve, the length of the bridge, and the right-side superelevation must be considered significant factors associated with driving safety while designing the road under high-speed driving conditions. CONCLUSIONS : Based on the findings of this study, a set of recommendations for designing roads was proposed. For example, the proper length of the combined alignment and the horizontal curve should be determined to prevent crashes due to hazardous lateral driving events because the installation of sufficient superelevation in the bridge section would be limited under high-speed driving conditions. In addition, applying a larger horizontal curve radius with longitudinal grooving is a promising approach to tackle risky driving conditions.

IMO에서는 선박으로부터 온실가스 감축을 위해 선박의 에너지효율 증진에 관한 논의를 진행하고 있다. 현재, 선박으로부터 발생되는 폐열을 이용한 ORC 발전 시스템을 적용함으로써 선박으로부터 높은 에너지 변환 효율을 기대할 수 있다. 이 기술은 물보다 더 낮은 온도 범위에서 증발하는 프레온 또는 탄화수소 계통의 유기 매체를 작동 유체로 사용한다. 이를 통해 상대적으로 낮은 저온에서 증기 (기체)를 생성 및 동력을 발생시킬 수 있다. 본 연구에서는 유기 랭킨 사이클인 ORC 발전 시스템에서 냉매와 폐열 사이 열·유동해석 (Analysis of Heat flow)을 3D 시뮬레이션 기법을 이용하여 구조물의 내·외부에 흐르는 유체가 온도 변화, 속도 변화, 압력 변화 및 질량 변화를 통해서 구조물에 어떤 영향을 미치는지를 분석하고자 하며, 동 연구는 이 기법을 이용하여 ORC 발전 시스템에서 냉매와 선박 주기 관의 배기가스로부터 일어나는 열교환기의 열전달을 해석하였다.

Deuterium is a crucial clean energy source required for nuclear fusion and is a future resource needed in various industries and scientific fields. However, it is not easy to enrich deuterium because the proportion of deuterium in the hydrogen mixture is scarce, at approximately 0.016%. Furthermore, the physical and chemical properties of the hydrogen mixture and deuterium are very similar. Therefore, the efficient separation of deuterium from hydrogen mixtures is often a significant challenge when using modern separation technologies. Recently, to effectively separate deuterium, studies utilizing the ‘Kinetic Quantum Sieving Effect (KQS)’ of porous materials are increasing. Therefore, in this review, two different strategies have been discussed for improving KQS efficiency for hydrogen isotope separation performance using nanoporous materials. One is the gating effect, which precisely controls the aperture locally by adjusting the temperature and pressure. The second is the breathing phenomenon, utilizing the volume change of the structure from closed system to open system. It has been reported that efficient hydrogen isotope separation is possible using these two methods, and each of these effects is described in detail in this review. In addition, a specific-isotope responsive system (e.g., 2nd breathing effect in MIL-53) has recently been discovered and is described here as well.

본 연구에서는 DNA barcode 시험법을 이용하여 시중 유통 중인 도미와 옥돔 수산가공식품의 위변조현황을 분석하였다. 참돔 12건, 돌돔 4건, 황돔 7건, 감성돔 2건, 나일틸라피아 7건, 옥돔 6건, 옥두어 8건 총 46건의 시료에 대해 실험을 진행하였다. 생물 종 판별에 주로 이용되는 mitochondrial DNA의 COX I (cytochrome C oxidase subunit I) 유전자 영역을 분석하여 원재료의 종을 판정하였다. NCBI에서 제공하는 BLAST Search 프로그램을 이용하여 분석된 염기서열과 NCBI에 등록된 각각 어류의 유전자 염기서열을 비교하였다. 분석 결과 염기서열 상동 성(identity)이 97% 이상인 종을 원재료 종으로 판별하였다. DNA barcode 시험법을 이용해 시중 유통되는 참돔, 돌돔, 황돔, 감성돔, 나일틸라피아, 옥돔, 옥두 수산가공품 46건에 대해 조사한 결과 위변조 사례는 나타나지 않았다. 그러나 시장에서 통용되는 일반명칭과 식품공전에 기술된 표준명칭이 상이하여 소비자의 혼란을 야기할 수 있어 수산물 가공식품 표기에 일반명칭과 더불어 표준명칭 또는 학명을 같이 기술하여야 할 것으로 판단되었다.

The emission of particulate matter and volatile organic compounds (VOCs) from a motor vehicle painting booth was quantitatively evaluated. Most particulate matter was emitted during the spraying process, in which the PM10 concentration was 16.5 times higher than that of the drying process. When the paint was being sprayed, the particles with a diameter of 1.0~2.5 μm accounted for 39.4% and particles greater than 2.5 μm in diameter accounted for 30.6% of total particles. On the other hand, small particles less than 0.5 μm in diameter accounted for 52.4% of total particles during the drying process. In contrast to the particulate matter, high concentrations of VOCs were emitted during both spraying and drying processes. Butyl acetate, xylene, toluene, and m-ethyltoluene were the most abundant VOCs emitted from the motor vehicle painting booth. Additionally, xylene, butyl acetate, toluene, and 1,2,3-trimethylbenzene were the dominant ozone precursors. Especially, xylene exhibited the highest ozone production contribution (32.5~44.4%) among 34 species of the ozone precursors. The information obtained in this study can be used to establish a suitable management strategy for air pollutants from motor vehicle painting booths.

In order to collect basic data for the improvement of fishing systems in coastal improved stow net fishery, a questionnaire survey and on-site hearing were conducted from May 10 to June 11, 2019 on the basic items of coastal improved stow net fishery and safety accidents that occurred during fishing operation. The questionnaire for the survey on the actual conditions of coastal improved stow net fishery consisted of a survey on basic matters (six questions) and a questionnaire (six questions) on safety accidents occurring during fishing operation. The results of the survey on basic items were analyzed by region (Incheon, Seocheon, Gunsan and Mokpo), by the captain’s age (less than 50 years of age, 50 to 60 years and more than 60 years of age), by the captain’s career (less than 20 years, 20 to 30 years, 30 to 40 years and more than 40 years) and by the age of fishing vessel (less than 10 years, 10 to 20 years and more than 20 years). According to the survey on basic items of coastal improved stow net fishery such as the captain’s age, the captain’s career, the age of fishing vessel, the fishing nets in use, the crews on board and the operation days per voyage by region, the average captain’s age was 55.7 years, the average captain’s career was 20.5 years, the average age of fishing vessels was 9.0 years, the average numbers of nets used by fishing boats was 14.0 sets, the average numbers of crew on board a fishing boat was 4.4 persons and the average numbers of operation days per voyage was 4.9 days (p < 0.05). As a result of the survey on safety factors during fishing operations, such as experience of ship accidents, major causes of ship accidents experienced, causes of ship accidents (first priority), experience of human accidents, major causes of human accidents, and causes of human accidents (first priority), more than 96% of the respondents experienced ship accidents including collisions with other vessels or fishing gear during fishing operations. The most significant cause of the accident was the other’s fishing gear installed in the fishing grounds. The first possible causes of ship accidents during fishing operations were found to be other fishing gear installed in fishing grounds, steering or engine failure, and inability to avoid accidents during casting and hauling nets. The survey of the experience of human accidents, such as injuries or sea falls, showed that more than 90% of the respondents experienced human accidents during fishing operations. The most important cause of accidents experienced during fishing operations was stucked in a fishing gear during casting and hauling nets. The first important causes of accidents during fishing operations were movement of the fishing gear during casting and hauling nets, damage of the fishing gear such as rope cutting. The results are expected to be provided as a basic data to prevent safety accidents occurring during fishing operation and improve the fishing system in the coastal improved stow net fishery.

The purpose of this study was to evaluate microbiological contamination of knives and cutting boards in child-care centers. Materials used in this study were swabbed of cutting boards and knives (blade, handle of knife, and joint of handle and blade) in 129 child-care centers. Mean values of total aerobic bacteria of swabs of knives and cutting boards were 1.7±0.7 log cfu/100 cm2 and 1.7±0.9 log cfu/100 cm2, respectively. Contamination levels of coliform bacteria from knives and cutting boards were 1.5±0.6 log cfu/100 cm2 and 1.7±0.8 log cfu/100 cm2, respectively. Comparing microbiological contamination levels of knives and cutting boards according to type and size of child-care centers, there was no significant difference. Bacillus cereus was detected in knife handles and cutting boards. Diarrhea-type toxin gene (entFM) was detected in B. cereus isolates. Antibiotic resistance tests showed that B. cereus was resistant to β-lactam antibiotics. To reduce microbiological contamination levels of knives and cutting boards in child-care centers and prevent food poisoning from bacteria contamination, continuous education by children's food-service management center is needed for sterilization and disinfection of knives and cutting boards.

The purpose of this study was to evaluate the quality characteristics of white pan bread added with wheat sprout powder without treatment (WP) and wheat sprout powder with only enzyme treatment (WPE), only lactic acid bacteria treatment (WPL) and enzyme and lactic acid bacteria treatment (WPE&L). The three different powder concentration levels of 1%, 3%, and 5% were added to flour to produce the white pan bread. The bread volume and specific volume of the WPE&L group were the highest among all the addition groups. The bread weight, a-value, and b-value of the WP group was highest among all the addition groups, but the bread baking loss and the L-value of the WP group was the lowest among all the addition groups. The texture measurements indicated that the hardness, gumminess, and chewiness values of the bread were the highest in the WP group. The sensory evaluation test showed that bread in the WPE&L group with 3% wheat sprout powder was the best among all the samples studied. Based on our findings, we suggest that the enzyme and lactic acid bacteria pretreated wheat sprout powder is an effective ingredient for improving the overall quality of white pan bread.

본 연구에서는 민어과 수산물의 표준시료 DNA 염기서열을 분석한 후 DNA barcode 염기서열을 확정하고 검증한 후 시중 유통 중인 민어과 수산가공식품의 위변조 현황을 조사하였다. 표준시료의 미토콘드리아 cytochrome coxidase subunit I유전자를 증폭한 후 증폭된 PCR 산물의 염기서열을 분석하였다. 분석결과 종 판별에 특이적인 655 bp를 선정하여 DNA barcode 염기서열로 하였다. DNA barcode information과 primer set을 이용한 진위판별 정확성을 확인한 결과 PCR 증폭은 모두 확인되었다. NCBI에 등록된 각각 어류의 유전자 염기서열과 비교하였을 때 참조기 100%, 부세 100%, 보구치 100%, 민어 100%의 상동성을 나타내어 실험에 사용된 DNA barcode information 과 primer set의 정확성을 확인하였다. DNA barcode 시험 법을 이용해 시중 유통되는 민어과 수산가공품 32건에 대 해 조사한 결과 위변조 사례는 나타나지 않았다. 그러나 식품공전에 등재된 보구치 대신 백조기라는 일반명이 사용되고 있어 소비자에게 혼란을 야기하고 있었다. 따라서 수산가공품 원재료 표시에 일반명과 더불어 표준명 또는 학명을 표시하여야 할 것으로 판단되었다.