This study aims to explore the appropriate water pressure control of water supply pipeline to reduce water losses of water supply network in Jinan-gun. The current water pressure status of each 5 blocks and the impact of optimized water pressure on improving revenue water rate were investigated. In order to obtain the flow rate and water pressure data of each small block, a smart hub is set in the pressure reducing valve chamber at the inlet of the small block, and a smart water pressure meter is installed in the fire hydrant and the faucet of the customer. For the pressure reducing valves installed for water pressure management system of each block, the diameter calculation standard and type of the pressure reducing valve are determined, and the application reasons are put forward. The analysis results of water pressure management for each small block in Jinan-gun show that the pressure control equipment and water pressure management need to be improved in four small blocks. The water flow rate in Jinan-eup and Sangjeon-myeon increases from 57.2% to 87.6% when the water pressure control is completed.

Gastrodia elata Bl. (GE) is a traditional herbal medicine used for the treatment hypertension and cerebrovascular disease. The purpose of this study was to investigate the antioxidant effect and blood pressure control ability of the GABA containing fermented Gastrodia elata Blume. The fermentation strain provided by Dr. Gi in Seoul National University is L. brevis GABA100, excellent strain of GABA production, which is involved in the ability to degrade gastrodin glycosides and activation of brain function. The Gastrodia elata Blume fermented by Lactobacillus brevis GABA 100 showed antioxidant activity (total phenolic contents, DPPH radical and ABTS anion scavenging activities) than unfermented Gastrodia elata Blume. In the spontaneously hypertensive rats (SHR), the concentration of fermented Gastrodia elata Blume was administered at 500, 1,000, and 2,000 mg/kg for 8 weeks. Systolic blood pressure decreased statistically significantly (p<0.05), especially 2 weeks after feeding fermented Gastrodia elata Blume. Also, it showed a significant decrease in low, medium, and high concentrations of fermented Gastrodia elata Blume at 4 weeks and 8 weeks. These results indicated that Gastrodia elata Blume fermented by the excellent strain of GABA production L. brevis GABA100 shows the antioxidant function and the effect of suppressing the increase in blood pressure.

In this study, three kinds of metal chills such as SS400, AC4CH and brass, with different thicknesses of 40 ~ 80 mm, were applied for low pressure casting of Al-Si alloy to control cooling rate. The microstructural characteristics with increasing cooling rate were represented using factors including D1, D2, size of primary α phases and shape factor and size of eutectic Si. The tensile properties were investigated and additionally analyzed based on the microstructural characteristics. As the cooling rate increased, D1, D2, and sizes of primary α phases and eutectic Si apparently decreased and the shape factor of eutectic Si increased to over 0.8. The ultimate tensile strength (UTS) and yield strength (YS) increased with decreasing D1, D2, and size of primary α phases, while elongation increased with decreasing size of eutectic Si and concurrently increasing shape factor of eutectic Si. This indicated that the primary α phases and eutectic Si in Al-Si alloy were refined with increasing cooling rate, resulting in improvement of UTS and YS without sacrificing elongation. After the tensile test, preferential deformation of primary α phases was observed in the Al-Si alloy produced at higher cooling rates of more than 0.1 K/s.

The 3-way valve have been used as a valve for opening and closing the valve by the flow control in the pressure system of the cryogenic and high pressure environment. In this paper, numerical analysis and experimental study on fracture nipple of 3-way ultra high pressure valve applied to space launch vehicle was carried out. We have developed a 3-way valve numerical simulation modeler of cryogenic environment using commercial software ANSYS 18.2. As results of numerical analysis, optimum nipple condition was derived. In addition, a 3-way valve prototype was fabricated and the fracture test was performed and compared with the numerical analysis results.

본 연구는 다문화가정 청소년의 또래압력이 비행에 미치는 영향에서 자기통제력의 매개효과와 부모의 정서적 지지의 조절효과를 확인하기 위하여 부산지역 다문화가정 청소년 중 현재 초･중･고에 재학 중인 청소년을 대상으로 연령별로 할당하여 총 433 명을 대상으로 분석이 이루어졌다. 연구결과 첫째, 다문화가정 청소년의 또래압력은 비행에 정적영향을 주며, 자기통 제력에는 부적영향을 주는 것으로 나타났다. 둘째, 자기통제력이 비행에 부적영향을 주었으며, 셋째, 다문화가정 청소년의 또래압력과 비행과의 관계를 자기통제력은 부분 매개효과를 가지며, 부모의 정서적 지지는 조절효과를 가지는 것으로 나타났다. 이상 의 연구결과를 통하여 본 연구에서는 다문화가정 청소년의 자아통제력과 부모의 정서 적 지지를 높이기 위한 방안을 제언하였다.

This paper presents the design and automatic control methods employed to implement a open-close mechanism for a food compression processor. The automatic open-close mechanism is intended as a robust approach in compressing incoming food that posses a wide range of physical properties. The method is based on the estimation of compression pressure through current measurement. Test results show that the proposed mechanism effectively controls the compression pressure of the processed food which results in enhanced overall system robustness.

In the present work, bismuth nanopowders with various particle size distributions were synthesized by controlling argon (Ar) gas flow rate and chamber pressure of a gas condensation (GC) apparatus. From the analyses of transmission electron microscopy (TEM) images and nitrogen gas adsorption results, it was found that as Ar gas flow rate increased, the specific surface area of bismuth increased and the average particles size decreased. On the other hand, as the chamber pressure increased, the specific surface area of bismuth decreased and the average particles size increased. The optimum gas flow rate and chamber pressure for the maximized electrochemical active surface area were determined to be 8 L/min and 50 torr, respectively. The bismuth nanopowders synthesized at the above condition exhibit 13.47 of specific surface area and 45.6 nm of average particles diameter.

부표시스템 침수체의 주요형상인 실린더에 원형 제어봉을 부착하여 2차원 단면의 유동특성에 대해서 수치해석을 수행하였다. 유속을 0.1m/s에서 0.5m/s로 변화시키면서 부표시스템 주위의 유동현상을 파악하고, 부표시스템의 효과적인 유동제어를 위해 실린더 (D=50mm)에 제어봉의 직경을 0.1D 에서 0.5D까지 부착하여 조류에 의한 압력분포를 조사하였다. 유동장내의 속도분포는 PIV 계측기법 중 2프레림 입자추적 법을 사용하여 수치해석의 정도를 높이고자 0.3m/s에서 비교 평가하였다. 실린더 주위의 압력분포는 0.2D의 제어봉을 부착하였을 경우, 유속의 변화에 관계없이 가장 양호한 경향을 보이는 것을 알 수 있었다.