본 연구에서는 CH4/CO2 혼합가스에서 CO2 분리를 위해 세라믹 중공사 접촉막 모듈(HFMC)을 이용하여 실험을 수행하였다. 고 내구성의 HFMC를 제작하기 위해, 고강도의 중공사막을 제조하여 평가하였다. 제조한 중공사막을 이용하여 HFMC를 제작하였고, 실험은 CH4/CO2 혼합 기체(30% CO2, CH4 balance)와 monoethanolamine (MEA)를 사용하였다. HFMC 운전 중 기체와 흡수제의 압력이 CO2 제거 효율에 어떠한 영향을 주는지 평가하였다. CO2 제거 효율은 기체압력이 증가함에 따라 같이 상승하였으며, CO2 흡수 flux 또한 액체유량과 함께 증가하는 추세를 보였다. 또한 CO2 흡수율이 40% 이하일 때 는 흡수제가 아래쪽에서 들어가는 향류형태인 LTS-1이 흡수제가 위쪽에서 들어가는 향류형태인 LTS-2보다 CO2 제거 성능 이 높았으며, 흡수율이 40% 이상일 때는 LTS-2가 LTS-1보다 성능이 높았다.

At a two phase flow, according to gas and liquid phase flow rates, various flow regimes are developed such as bubbly, slug/plug, churn, annular, droplet flow and so on. At a two phase flow in small scaled channels, among various flow regimes, the intermittent flows such as bubbly, slug/plug flow are developed in the broad regions of two phase flow pattern map. In particular, the flow regimes are influenced by surface wettability. In a case of slug flow in hydrophobic small scaled channels, gas and liquid phases are perfectively separated by interfaces and contact line. The pressure drop of the two-phase flow is largely generated at moving contact line. Therefore, to well design two-phase flow system with small scales, it is important to estimate the pressure drop at moving contact line. In this study, on the basis of previous research, the pressure drop at moving contact line is experimentally measured for a various fluids (0-40% water-ethanol mixtures). And, the previous correlation to estimate pressure drop at moving contact line is verified by experimental data. In an addition, we discuss interfacial broken phenomena of slug flow in a minichannel. (D=1.555mm).

압력-분배 탈기방식으로 막접촉기를 구성하여 바이오가스 정제를 하였다. 폴리프로필렌(PP) 중공사막 모듈과 물리흡수제를 이용하여 막접촉기 성능 평가를 수행하였다. 실험은 흡수 압력, 가스의 유량, 흡수 온도 및 흡수제의 농도등 다양한 조건에서 수행하였다. 특히 CO2 흡수능이 높은 상용 흡수제인 프로필렌카보네이트(PC)와 물의 혼합흡수제를 사용하여 회수성능이 향상되었다. 탈기 방법이 개선된 압력-분배 탈기방식의 막접촉기는 50% CO2/50% CH4의 바이오가스 모사가스로부터 바이오메탄을 98% CH4 순도와 91%의 회수율로 정제하였다. 따라서 압력-분배 막접촉기를 통해 바이오가스로부터 수송용 바이오메탄의 생산이 가능함을 확인하였다.

V-Coupling is used as a mechanical fastener to connect the turbine housing and the bearing housing in a turbocharger. The back plate is located between the turbine housing and the bearing housing, which is compressed by the bolt clamping force of coupling to prevent gas leakage under turbocharger operation. This paper presents the theoretical and analytical methods to predict the sealing performance by calculating the contact pressures on the back plate. The mathematical model was constructed to derive the contact force on the back plate by considering the force transfer mechanism. And, finite element analysis was carried out to predict the contact pressures by applying the bolt load in the coupling system. As a result, the analysis results of the mathematical model are well consistent with the results of the finite element analysis. Therefore, in the early design stage of turbocharger coupling, mathematical model would be helpful to determine the design parameters.

무릎 임플란트에서 접촉압력이 마모에 큰 영향을 미친다. 본 연구에서는 본 연구기관에서 개발한 무릎 임플란트 모델을 이용하여 유한요소해석을 하였다. 연구와 산업에서 실제로 사용하는 조합을 이용하여 총 10가지의 무릎 임플란트의 재료조 합에 대한 접촉압력을 분석하였다. 무릎이 30도, 45도 60도 기울어져있을 때의 하중을 가하여 접촉압력을 구하였다. 접촉압 력을 계산한 결과 티타늄합금-UHMWPE 조합에서 가장 작은 접촉압력이 나왔다. UHMWPE의 경우 대퇴골부에 어떠한 재 료를 사용하여도 접촉압력이 크게 변하지 않았다. 접촉압력이 가장 큰 조합과 작은 조합을 비교하였을 때 0.77% 차이를 보 였다. 반면에 Carbon/PEEK 복합재료의 경우 접촉압력이 가장 큰 경우와 작은 경우를 비교하였을 때 5.3% 차이를 보였다. 이를 통해 Carbon/PEEK 복합재료를 베어링부로 사용할 경우 대퇴골부의 재료가 마모에 영향을 미침을 알 수 있다. 본 연구 는 무릎 임플란트 마모예측과 마모를 최소화 연구에 도움이 될 것이라 생각한다.

The ozonation process has been widely used for drinking water disinfection around the world. Recently, the pressurized ozone contactor, in which the side stream typed ozone injection method is installed, has been applied to water treatment system. In this study, numerical calculations were conducted to compare prototype and screw-type ozone contactors based on hydraulic effectiveness in more details. The prototype ozone contactor was already installed and operated in domestic water treatment plant, and the screw-type is the suggested one for improving ozone contact efficiency installing the screw plate to the prototype. Screw turn numbers of screw plate were changed as 3, 5, 7 and 9, respectively for numerical simulation. The CT(concentration of disinfectant in mg/L times time in minutes) value was considered as one of the options for evaluating disinfection ability. From the results, it could be concluded that the performance of the screw-type is higher than that of the protype contactor by controlling the variable T as the tracer time. Also, Morill index of the screw-type(turn numbers = 5 ) appeared to be lower than the other.

The users who use the wheelchair are confined to a wheelchair for a long time. Accordingly, the use of seat cushion for pressure distribution is very important in order to prevent a bedsore. Therefore, this paper provides useful information for design of seat cushion through statistical testing among nothing cushion, low cell type of air cushion, high cell type of air cushion, and jelly type of air cushion. It turned out that the jelly type and high cell type of air cushion have a serious effect on decision and design of seat cushion.

In this paper we present a novel robotic palpation method for the lump shape estimation using contact pressure distribution. Many previous researches about the robotic palpation have used a stiffness map, which is not suitable to obtain geometrical information of a lump. As a result, they require a large data set and long palpation time to estimate the lump shape. Instead of using the stiffness map, the proposed palpation method uses the difference between the normal force direction and the surface normal to detect the lump boundary and estimate its normal. The palpation trajectory is generated by the normal of the lump boundary to track the lump boundary in real-time. The proposed approach requires small data set and short palpation time for the lump shape estimation since the shape can be directly estimated from the optimally generated palpation trajectory. An experiment result shows that our method can find the lump shape accurately in real-time with small data and short time.