This study was conducted to evaluate the filtration performance according to the feed temperature composed of NaCl and the operating pressure of the brackish water reverse osmosis (BWRO) process. The temperature is known that decides the filtration performance of reverse osmosis (RO). It is noted that temperature increase activates the permeate of salts due to augment of diffusivity and mass transfer. Filtration of the lab-scale RO system was performed with constant pressure and the constant flow was simulated. The salt rejection measured by the concentration of the feed and permeate was compared with water permeability and salt permeability in the conditions containing various temperatures (5, 10, 15, 20, 25, and 30℃) and pressures (10, 12, 15, and 18 bar). An increase in feed temperature from 5 °C to 30 °C caused a 4.65% decrease in salt rejection in CSM, due to an increase in salt permeability (4.06 times) rather than an increase in water permeability (2.62 times). Specific energy consumption (SEC) was calculated by using an electricity meter set in the RO system. It was expected that the SEC by the increases in temperature and pressure decreased due to the viscosity decline of the feed and the permeate flux augment, respectively. The SEC decreased by 63.4% in CSM and by 54.3% in Nittodenko when the feed temperature increased from 5 °C to 30 °C. It discussed how to operate the optimal RO process through the effect of temperature and operating pressure and the comparison of SEC.

Barnea manilensis is a bivalve which bores soft rocks, such as, limestone or mudstone in the low intertidal zone. They make burrows which have narrow entrances and wide interiors and live in these burrows for a lifetime. In this study, the morphology and the microstructure of the valve of rock-boring clam B. manilensis were observed using a stereoscopic microscope and FE-SEM, respectively. The chemical composition of specific part of the valve was assessed by energy dispersive X-ray spectroscopy (EDS) analysis. 3D modeling and structural dynamic analysis were used to simulate the boring behavior of B. manilensis. Microscopy results showed that the valve was asymmetric with plow-like spikes which were located on the anterior surface of the valve and were distributed in a specific direction. The anterior parts of the valve were thicker than the posterior parts. EDS results indicated that the valve mainly consisted of calcium carbonate, while metal elements, such as, Al, Si, Mn, Fe, and Mg were detected on the outer surface of the anterior spikes. It was assumed that the metal elements increased the strength of the valve, thus helping the B. manilensis to bore sediment. The simulation showed that spikes located on the anterior part of the valve received a load at all angles. It was suggested that the anterior part of the shell received the load while drilling rocks. The boring mechanism using the amorphous valve of B. manilensis is expected to be used as basic data to devise an efficient drilling mechanism.

PURPOSES : The purpose of this study was to investigate the characteristics of concrete pavement behaviors and performance depending on the group-axle types of heavy vehicles, such as single-, tandem-, and tridem-axles. METHODS : The concrete pavement performance indices (such as the rate of fatigue cracking and surface smoothness) according to the different group-axle types of heavy vehicles were predicted using the Korean pavement design program. It was assumed that the load magnitude was the same for each axle, and that the equivalent single-axle traffic volumes were the same for the different group-axle types. The concrete pavement stresses depending on the different group-axle types of heavy vehicles were also analyzed using a finite element analysis program. RESULTS : Based on the design criteria, the concrete pavement performance was the highest under tandem-axle traffic and lowest under single-axle traffic, although the difference in performance was not significant. Based on the structural analysis criteria, the tensile stress of the concrete pavement was the largest under the single-axle load and smallest under the tridem-axle load when the load magnitude of each axle was the same. CONCLUSIONS : Based on the results obtained from considering both the design and analysis criteria, it was concluded that the groupaxle types (such as the tandem- and tridem-axle configurations of heavy vehicles) would not increase the stress or decrease the performance of concrete pavements relative to the single-axle configuration.

목적 : 본 연구는 요양시설에 거주하는 65세 이상 노인들을 대상으로 한국형 활동분류카드(Korean Activity Card Sort; K-ACS)를 통해 참여활동수준을 측정하고, 삶의 질에 미치는 요인에 대해 알아보 고자 하였다. 연구방법 : 2021년 7월 1일부터 2021년 8월 31일까지 수도권 요양시설 거주 노인 78명을 대상으로 자 가 보고식 설문지와 평가를 실시하였다. 대상자들의 참여활동수준, 우울, 자기효능감, 일상생활수행능력, 삶의 질과의 관계를 피어슨 상관분석과 다중회귀분석으로 알아보았다. 결과 : 요양시설 거주 노인을 대상으로 참여활동수준을 측정한 결과 전체 참여활동수준 27.8%, 수단적 일 상생활활동수준 26.9%, 여가활동수준 36.5%, 사회활동수준이 21.0%로 나타났다. 전체 참여활동수준은 수단적 일상생활활동수준(r = .937, p < .01), 사회활동수준(r = .858, p < .01)과 높은 상관성을 보 였다. 또한 삶의 질에는 정신적 요소인 우울(β = -.514, p < .001)과 자기효능감(β = .266, p < .05) 이 영향을 미치는 것으로 확인되었다. 결론 : 작업치료사는 노인들의 성공적인 노화를 돕기 위해 시설 내에 다양한 활동프로그램을 마련하고 노 인들이 활동에 참여할 기회를 제공하여야 한다. 이러한 작업치료사의 역할은 시설 거주 노인의 우울감을 완화하고 자기효능감, 참여활동수준을 높임으로써 궁극적으로 삶의 질을 향상시킬 것으로 기대된다.

A typical low and medium-sized neighborhood living facility in reinforced concrete building secures a high floor and pursues an efficient module plan(long span). Accordingly, research on the development of new hybrid beams that can innovatively reduce labor costs such as on-site installation and assembly while securing strength and rigidity is ongoing. In order to verify the structural performance of the U-flanged truss composite beam with newly developed shape, Experiments with various variables are required. Based on the results, this study is to evaluate the strength of U-flanged truss hybrid beam through the flexural strength of the Korea Design Code and experimental values. It was evaluated that nominal flexural strength was 110% to 135% higher than the experimental value.

광전기화학 성능을 향상시키기 위해 각 ZnO, ZnSe과 g-C3N4 소재의 장점을 살리도록 3성분계 적층 구조를 디자 인했다. 용액공정으로 FTO 기판위에서 ZnO 나노로드 어레이가 성장하도록 한 후 ZnO표면에 Se을 부착시켜 ZnO표면에 서 ZnSe층이 형성 되도록 이온 치환법을 도입하였다. ZnO/ZnSe 나노로드 위에 g-C3N4 층을 스핀코팅 한 후 각 층이 화 학적 접합이 되도록 질소 분위기 하에서 열처리를 하였다. AM 1.5G, 0.5 V 외부전압하에서 각 적층구조별로 광전기화학 적 전류밀도를 측정하였고 비교 결과 ZnO/ZnSe/g-C3N4 나노로드가 ZnO 및 ZnO/ZnSe 나노로드에 비하여 보다 높은 광 전류 밀도가 측정되었다. 수직 정렬된 ZnO 육각 프리즘형태는 큰 비표면적과 축 방향을 따라 전자 흐름을 원활히 하고, ZnSe 층은 비표면적과 광흡수 범위를 더욱 넗히는 효과를 가져왔다. 이로 인하여 ZnO/ZnSe/g-C3N4 삼원 접합 전극의 향상된 성능은 가시광선 흡수범위 확장, 전하 분리 강화 및 전자 전도도 향상으로 인한 시너지 효과에 기인되는 것으로 판단된다.