정삼투막 성능 예측에는 Solution-diffusion model이 지배적으로 활용되어 왔으나, 기존 연구에서 수압과 삼투압이 동시에 작용하는 가압형 정삼투 공정에 대한 예측정확도가 감소하며, 이를 위해 수압이 투과성능에 미치는 영향을 convection과 diffusion을 동시에 고려해야한다는 연구결과가 보고되었다. 본 연구에서는 CTA-ES 및 PA-TFC 정삼투막을 이용하였으며, 활성층 측에는 NaCl 용액을, 지지층 측에는 증류수를 주입하고, 활성층 측에 삼투압과 동일한 수압을 가하여 농도변화에 따른 수투과도 및 염투과도의 변화양상을 평가하였다.

In this paper, we developed the hydraulic leveling jack(HLJ) with double-tube type structure which could be applicable to excessive lateral load area. In order to develop HLJ, the design requirements, such as the vertical and lateral loads where applied to hydraulic jack, were selected. To verify the structural stability of the HLJ, the structure analysis was performed. In order to verify the operational performance and structural stability of the developed HLJ, test bench was designed. The performance of HLJ was verified via various test using test bench.

The pneumatic hydraulic braker which is attached to an excavator is widely used in the construction industry field, and is increasing its capacity and performance because many users want high power and efficiency of the pneumatic hydraulic braker. The structure of a pneumatic hydraulic braker is composed of piston, rod(chisel), back head gas chamber, and directional control valve. The performances of a pneumatic hydraulic braker are impact force, impact energy, impact rate, etc., and depend on the hydraulic components and system. This paper will argue that the performances are investigated and analysed using the AMEsim program which is used in hydraulic and pneumatic system. It is shown that the performances of the heave duty pneumatic hydraulic braker are good in many fields relative to other brakers during the simulation process

This paper describes the results of the application of Cr-Diamond-like carbon (DLC) films for efficiency improvement through surface modification of spur gear parts in the hydraulic gear pump. Cr-DLC films were successfully deposited on SCM 415 substrates by a hybrid coating process using linear ion source (LIS) and magnetron sputtering method. The characteristics of the films were systematically investigated using FE-SEM, nano-indentation, sliding tester and AFM instrument. The microstructure of Cr-DLC films turned into the dense and fine grains with relatively preferred orientation. The thickness formed in our Cr buffer layer and DLC coating layer were obtained the 487 nm and . The average friction coefficient of Cr-DLC films considerably decreased to 0.15 for 0.50 of uncoated SCM415 material. The hardness and surface roughness of Cr-DLC films were measured 20 GPa and 10.76 nm, respectively. And then, efficiency tests were performed on the hydraulic gear pump to investigate the efficiency performance of the Cr-DLC coated spur gear. The experimental results show that the volumetric and mechanical efficiency of hydraulic gear pump using the Cr-DLC spur gear were improved up to 2~5% and better efficiency improvement could be attributed to its excellent microstructure, higher hardness, and lower friction coefficient. This conclusion proves the feasibility in the efficiency improvement of hydraulic gear pump for industrial applications.

A valve open/close degree measuring device is used for an indicator of a valve actuator. This device indicates an opening and closing of a valve or throttle in a hydraulic actuator. In ship, equipments requires safe and robust because of a rough environment and a specific condition during a voyage. Thus, the open/close degree measuring device must be developed which can be used at an outdoor environment. This study developed the open/close degree measuring device using a volumetric measuring method(25㎖/100㎖). The housing of the open/close degree measuring device was made by a stainless steel with surface painting after an anodizing coating.

분사류의 굴삭성능을 이용하여 해저의 모래속에서 서식하고 있는 패류를 어획할 목적으로 원형과 직사각형의 모형노즐을 제작하여 수조에서 분사노즐의 모래면에 대한 굴삭실험을 한 결과를 요약하면 다음과 같다. 1. 분사노즐에 의한 모래면의 최대 굴삭깊이와 폭은 분사속도와 노즐의 단면적의 크기에 비례하여 직선적으로 증가하며, 노즐의 분사거리에 대해서는 굴삭깊이는 직선적으로 감소하나, 굴삭폭은 직선적으로 증가한다. 2. 직사각형 노즐(폭 1mm)은 단면적이 같은 원형 노즐보다 굴삭성능이 다소 우수하였다. 3. 노즐별 분사각도와 분사속도, 분사거리에 따른 최대 굴삭깊이와 폭에 관한 실험식은 직선식으로 나타나며, 분사각도 45˚에서 직사각형노즐(폭 1mm)의 분사속도와 분사거리에 따른 실험식은 다음과 같다. D=0.0093V 하(0)-0.23H+5.7. W=0.0147V 하(0)+1.06H+10.2. 단, D: 최대 굴삭깊이(cm), V 하(0): 노즐의 분사속도(cm/sec) 926≤V 하(0)≤1504, W: 최대굴삭폭(cm), H: 노즐구멍에서 모래면까지의 거리(cm).

In this paper, a hydraulic damper was developed to protect the storage racks from earthquakes and the seismic performance of the storage racks was improved by applying the developed damper. In order to achieve these goals, the control capacity for the safety of the storage racks was determined, and a hydraulic damper satisfying the control capacity was designed and manufactured. In addition, the location of the hydraulic damper was determined through simulation. Finally, the shaking table test was carried out. As a result, the seismic performance improvement of the storage racks using the hydraulic damper was confirmed.

This study evaluated the standard consistency, setting time, hydration heat, and compressive strength of binary blended cement concrete (general and high strength) using air cooled ladle furnace slag (LFS) of 3, 5, 7, 10wt.% as an admixture for ordinary portland cement (OPC). Results showed that binary blended cements using the LFS of lower than 5wt.% shortened the setting time and reinforced the compressive strength of concrete (general and high-strength) compared to OPC concretes although binary blended cements needed more water to achieve the standard consistency. This indicated that LFS could be used as a useful admixture for manufacturing binary blended cement. Thus, we expected that the upcycling of LFS would be contributed to save energy consumption and reduce the greenhouse gas emission from the field of cement industry.

하도육역화는 상류로부터 내려온 유사가 고수부지 또는 하도에 쌓여 하상이 상승하여 수역이 육역으로 변화하는 것을 말한다. 육역화는 통수단면의 감소로 인해 홍수위 상승이라는 문제를 야기한다. 홍수위가 상승하면 홍수위험도 함께 증가하기 때문에 하도육역화에 대한 관리가 필요하다. 이러한 하도육역화 방지 기술을 시험구간에 적용하여 실제 효과를 직접 검증하는 모니터링 연구가 진행중이며 본 연구에서는 수치모의를 통해서 모니터링으로 확인하기 힘든 유속의 분포와 유사의 이동경로 등을 확인하고자 한다. 유량조건은 평수기와 홍수기의 하천 모니터링 결과를 이용하였으며 동수역학적 특성은 유속분포와 난류강도 와도 등을 분석하였으며 유사이송적 특성은 FLOW-3D 상에서 입자(Particle)를 유하시켜 퇴적이 되는지 그대로 배제되는지를 분석하였다. 이 때 입자의 직경은 실제 하천에서의 중앙입경(d_50)으로 선정하였다. 본 연구에서는 하도육역화 방지기술의 설치 전후에 대한 비교를 통해 하도육역화 방지기술의 수리학적 성능을 검토하였다. 그 결과 현장적용된 하도육역화 방지기술은 고수부지 내 퇴적을 저감시키는 효과를 나타냈으며 유사의 연속성증진에 효과가 있는 것으로 나타났다. 추후 현장 모니터링 결과와 비교검증을 실시하면 보다 명확한 하도육역화 방지기술에 대한 수리학적 성능 검증뿐만아니라 수생태 건강성 증진에 대한 효과까지 검증이 될 수 있을 것이다.