This study examines earthquake-induced sloshing effects on liquid storage tanks using computation fluid dynamics. To achieve this goal, this study selects an existing square steel tank tested by Seismic Simulation Test Center at Pusan National University as a case study. The model validation was firstly performed through the comparison of shaking table test data and simulated results for the water tank subjected to a harmonic excitation. For a realistic estimation of the wall pressure response of the water tank, three recorded earthquakes with similar peak ground acceleration are applied:1940 El Centro earthquake, 2016 Gyeongju earthquake, and 2017 Pohang earthquake. Wall pressures monitored during the dynamic analyses are examined and compared for different earthquake motions and monitoring points, using power spectrum density. Finally, the maximum dynamic pressure for three earthquakes is compared with the design pressure calculated from a seismic design code. Results indicated that the maximum pressure from the El Centro earthquake exceeds the design pressure although its peak ground acceleration is less than 0.4 g, which is the design acceleration. On the other hand, the maximum pressure due to two Korean earthquakes does not reach the design pressure. Thus, engineers should not consider only the peak ground acceleration when determining the design pressure of water tanks.

본 연구는 팽이버섯 수확후배지를 효율적으로 이용하기 위하여 출수기의 수수 총체사일리지 제조 시 에너지원으로 사용하고자 수행되었다. 팽이버섯 수확 후 배지의 첨가비율은 원물기준으로 20%, 40% 및 60%로 하고 사일리지 발효기간을 0, 3, 6 및 9주로 하여 총 12처리를 두었으며 각 처리 당 3반복으로 비닐이 내장된 플라스틱 통에 제조하였다. 수수 사일리지 제조 시 팽이버섯 수확후배지의 첨가수준과 발효기간에 따른 발효특성과 사료적 가치를 평가한 결과는 다음과 같다. 사일리지 원료인 출수기 수수와 팽이버섯 수확후배지의 수분함량은 각각 83.8%와 54.3%였으며 팽이버섯 수확후배지를 20%(S-20), 40%(S-40), 60%(S-60) 첨가한 수수 사일리지의 수분함량은 각각 78%, 71%, 68%였고 S-20의 수분함량이 일반적인 수준보다 높았다. 팽이버섯 수확후배지 첨가 사일리지의 조지방 함량은 사일리지 충진 직후(0주)에 비해 저장 발효하는 동안 약 2배 이상 증가하였다(P<0.05). 팽이버섯 수확후배지 첨가비율에 따른 수수 사일리지의 pH는 평균 4.33수준이었으며 S-40구가 발효에 의한 pH의 감소폭이 큰 편이었다. 사일리지의 유산 함량은 S-40구에서 높은 편이었고 타 처리구에서는 저장기간이 길어짐에 따라 감소하는 경향이었으며 초산과 프로피온산 함량은 처리구와 발효기간에 따른 영향이 없었다. 사일리지 품질평가 기준으로 사용되고 있는 Flieg’s score는 60∼83점이였고 9주 동안 발효시킨 S-60구의 품질이 상대적으로 나빴던 반면 9주 동안 발효시킨 S-40구에서 우수한 사일리지가 제조되었다. 이상의 결과들을 종합해 볼 때, 수수 사일리지의 에너지 공급원으로서 팽이버섯 수확후배지의 적정 첨가비율은 원물기준으로 40%정도인 것으로 판단된다.

YAG:Ce yellow phosphor particles were synthesized by spray pyrolysis with changing the solution properties and their luminous properties, crystal structure, and morphological changes were studied by using PL measurement, XRD, and SEM analysis. It was clear that the solution properties significantly affected the crystal phase, crystallite size, the PL intensity, and the morphology of YAG:Ce particles. At low calcination temperature, the addition of urea only to the spray solution was helpful to form a pure YAG phase without any impurity phases, as the result, the highest luminescence intensity was achieved at the calcination temperature of . When the calcination temperatures were larger than , however, the YAG particles prepared without any additive showed the highest luminescent intensity. Regardless of the solution conditions, the emission intensity of YAG:Ce particles prepared by spray pyrolysis showed a linear relation with the crystallite size. In terms of the morphology of YAG:Ce particles, the addition of both DCCA and to the spray solution was effective to prepare a spherical and dense structured YAG particles.

Eu red phosphor was prepared by microwave synthesis. The crystal phase, particle morphology, and luminescent properties were characterized by XRD, SEM, and spectrofluorometer, respectively. The prepared :Eu particles had good crystallinity and strong red emission under ultravioletet excitation. The crystallite size increased with calcination temperature and satuarated at . The primary particle size initially formed was varied from 30 to 450 nm with microwave-irradiation (MI) time. It was found that the emission intensity of :Eu phosphor strongly depends on the MI time. In terms of the emission intensity, it was recommended that the MI time should be less than 15 min. The emission intensity of :Eu phosphor prepared by microwave syntehsis strongly depended on the crystallite size of which an optimal size range was 50-60 nm