• 한국농공학회논문집
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• 제47권2호
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• pp.87-96
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• 2005

In this research, an attempt is made to derive the practical estimation of the degree of consolidation in soft clay from field measurements under embankments. For the practical estimation of pore water pressure in soft clay, the elasto-viscous rheological model was proposed, with a transform of parameters and a field geotechnical measurements in southern Korea. By using the rheological properties of soft clays and the dissipation of excess pore water pressure behaviour during step loading, a degree of consolidation or pore water pressure estimation in the future can be performed, and are shown to be generally close to the field measurements of pore water pressure. Finally, a pore water pressure behaviour in soft clay can be explained through measured data in field and the excess pore water pressure data can also be used to estimate settlement.

• 한국광물학회지
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• 제9권1호
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• pp.35-42
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• 1996

Polycrystalline ZrH2 in tetragonal crystal system has been compressed in a modified Bassett-type diamond anvil cell up to 36.0 GPa at room temperature. X-ray diffraction data did not indicate any phase transitions at the present pressure range. The pressure dependence of the a-axis, c-axis, c/a and molar volume of ZrH2 was determined at pressures up to 36.0 GPa. Assuming the pressure derivative of the bulk modulus (K0') to be 4.11 from an ultrasonic value on Zr, bulk modulus (K0) was determined to be 160Gpa by fitting the pressure-volume data to the Birch-Murnaghan equation of state. Same sample was heated at $500^{\circ}C$ at the pressure of 9.8 GPa in a modified Sung-type diamond anvil cell. Unloaded and quenched sample revealed that the original tetragonal structure transforms into a hexagonal structured phase with a zero-pressure molar volume change of ~115.5%.

• 제어로봇시스템학회논문지
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• 제5권8호
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• pp.941-947
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• 1999

As pressure transducers are employed in many fields such as production facilities, test facilities vehicles and industrial machinery, there is an increasing need for high precision measurement of pressure without any calibration or maintenance. In this paper, we discuss the development of a smart thin film pressure transducer which is highly suitable for a precise measurement of pressure. The smart functions include automatic zero tracking, automatic span adjustment, temperature compenstion, continuous self-diagnostics for faults (open strain gages, abnormal data, incorrect A/D conversion, and overpressure), data memory and multi-drop communication with PC

• 한국자동차공학회논문집
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• 제11권2호
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• pp.119-125
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• 2003

An experiment study on pressure drop was carried out for both an adiabatic and a diabatic two-phase flow with pure refrigerants R134a and Rl23 and their mixtures as test fluids in a uniformly heated horizontal tube. The frictional pressure drop during flow boiling is predicted by using two models; the homogeneous model that assumes equal phase velocity and the separate flow model that allows a slip velocity between two phases. The measured frictional pressure drop was compared to a few available correlations. Homogeneous model considerally underpredicted the present data for mixture as well as pure component in the entire mass velocity ranges employed in the present study, while Friedel correlation was found to satisfactorily correlate the frictional pressure drop data as compared to other correlation.

• 대한안전경영과학회지
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• 제7권4호
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• pp.85-99
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• 2005

The main objective of this paper is to search whether containment vessel's best pressure may increase until how long when loss of coolant accident (LOCA) happened in containment vessel of Ulchin nuclear power plant 1 and 2. Another goal of this research is to find the influential factors that increase containment vessel pressure. Model for this research is Ulchin nuclear power plant 1 with 10 cycles. Data were collected by simulator of Ulchin nuclear power plant 1 and design of experiment was used for data analysis. For the experiment, seven factors that are going to influence in containment vessel pressure were chosen. It was found that fatter which influences in early rise of containment vessel pressure after LOCA is only explosion size. Also, containment vessel's best pressure (3.74 bar.a) was much lower than limit (4.86 bar.a) of FSAR (Final Safety Analysis Report).

• 한국전기전자재료학회논문지
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• 제17권4호
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• pp.426-431
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• 2004

We have studied the pressure-dependent liquid crystal's dynamics in a twisted nematic (TN) liquid crystal panel with thin film transistor by applying an external pressure to it. When the external pressure is applied to the panel in a dark state, the disclination lines were generated as a light leakage whereas they did not appear in a simple test cell that has only pixel and common electrodes. It was because the disclination lines were Provoked by the electric field between pixel electrode and data/gate bus line for active matrix driving. Consequently, the external pressure resulted in dynamic instability of the liquid crystal so that the disclination lines at the data/gate bus line intruded into the active area.

• 대한기계학회논문집B
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• 제32권6호
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• pp.479-486
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• 2008

The objective of this study is to investigate experimentally the characteristics of pressure drop in SMX type motionless mixers. The motionless mixers used are SMX-O, SMX-H, SMXL-O and SMXL-H ones. The SMX-H and SMXL-H mixer elements have been designed to reduce the pressure drop as compared with the SMX-O and SMXL-O ones. The Reynolds number based on the bulk average properties of the water is in a range of 5000 to 13000. The pressure drops across the motionless mixers are measured and the friction factors are calculated using the pressure drop data. On the average, the friction factors of the SMX-H and SMXL-H mixers are about 8% and 15% lower than those of the SMX-O and SMXL-O ones. In addition, the proposed correlations from the experimental data for the friction factor are presented and compared with those obtained from the literature.

• 한국추진공학회:학술대회논문집
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• 한국추진공학회 2017년도 제48회 춘계학술대회논문집
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• pp.1088-1092
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• 2017

본 논문에서는 액체로켓엔진 가스발생기 연소시험에서 서로 다른 동압 센서를 통해 측정한 동압 결과를 비교하였다. 열 충격에 의한 영향으로 서로 다른 방식 및 제조사의 센서는 시간에 따른 동압 차이가 발생함을 확인하였다. 하지만, 연소불안정 분석에 있어 중요한 인자인 특성주파수와 RMS 값에 있어서는 센서에 따른 차이가 미미함을 확인하였다.

• 한국연소학회지
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• 제19권1호
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• pp.11-16
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• 2014

Spherically expanding flames are used to measure flame speeds, which are derived the corresponding laminar flame speeds at zero stretch. Dimethyl Ether-Air mixtures at high pressure are studied over an extensive range of equivalence ratios. The classical shadowgraph technique is used to detect the reaction zone. In analytical methodology the optimization process using least mean squares is performed to extract the laminar flame speeds. It is seen that the laminar flame speed of DME-Air mixture with the increase of pressure decreases rapidly showing a similar trend to other hydrocarbon fuels. At pressure of 2 and 10 atm the experimental data from the present study agree well with results reported in the literature. Especially the laminar flame speeds at 2 atm are in good agreement with those calculated in numerical work over the full stoichiometric range. At elevated pressure of 12 atm the measured data are slightly slower at fuel lean condition and show close agreement at fuel rich condition when compared with the numerical results.

• 설비공학논문집
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• 제16권12호
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• pp.1227-1233
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• 2004

Air handling unit (AHU)'s air filter pressure difference is important for energy consumption and indoor air quality. Both energy Performance data and air filter differential pressure of AHU in real office buildings were monitored and analyzed to investigate quantitatively energy impact as dust buildup level on air filter grows. We also modeled and simulated CAV system using HVACSIM＋ program to examine the energy effect of dust buildup on filters. Through analysis of time series pressure drop data, the filter pressure difference rate has been increased due to cumulative supply air flow rate increase. As filter pressure drop increased to 1 inch water column, it is found that the supply air flow rate was decreased by 10%, the chilled water flow rate was increased by 5.9% and the pump energy consumption was increased to 5.9%.