• Proceedings of the KIEE Conference
• /
• 2011.07a
• /
• pp.551-552
• /
• 2011

In this study new evaluation method of eddy currents in conductive shielding sheets are introduced. This method is based on the magnetic flux linkage in rectangular cells. According to this method the allocated amount of memory and the calculation time can be reduced. In this method calculation of magnetic field in any space can be performed by summing contributions of source currents and eddy currents in conductive shielding sheets. This method is applicable to the design of magnetic field-shield.

• Bulletin of the Korean Chemical Society
• /
• v.35 no.12
• /
• pp.3527-3531
• /
• 2014

In this paper, we report thermodynamic and transport properties (diffusion coefficient, viscosity, and thermal conductivity) of diatomic gases ($H_2$, $N_2$, $O_2$, and $Cl_2$) at 273.15 K and 1.00 atm by performing molecular dynamics simulations using Lennard-Jones intermolecular potential and modified Green-Kubo formulas. The results of self-diffusion coefficients of diatomic gases obtained from velocity auto-correlation functions by Green-Kubo relation are in good agreement with those obtained from mean square displacements by Einstein relation. While the results for viscosities of diatomic gases obtained from stress auto-correlation functions underestimate the experimental results, those for thermal conductivities obtained from heat flux auto-correlation functions overestimate the experimental data except $H_2$.

• Proceedings of the Korean Nuclear Society Conference
• /
• 1998.05b
• /
• pp.377-382
• /
• 1998

재료 조사시험용 계장캡슐은 하나로(Hi-Flux Advanced Neutron Application Reactor : HANARO) 를 이용하는 조사시설중의 하나이다. 캡슐 내부에 있는 열매체는 다공 원통구조물로 고려되며, 다양한 형태와 크기를 갖는 조사시험용 시편이 각 단에 삽입된다. 조사시험에 대한 사용자의 요구조건을 효율적으로 충족시키기 위해서는 캡슐 열매체에 대한 여러 역학적인 특성을 파악하여 설계 및 제작할 필요가 있다. 따라서 계장 캡슐 설계의 초기단계로서 다양한 기하학적인 설계변수를 갖는 다공 캡슐 열매체의 구조적 특성을 파악하기 위한 연구를 수행하였다. 조사 분위기인 하중상태에서의 다공 구조물에 대한 구조응력해석을 수행하여 다공 매개변수에 따른 응력 및 변위 등을 고찰하였고, 구조물의 건전성을 평가하였다.

• Journal of Radiation Protection and Research
• /
• v.24 no.4
• /
• pp.231-233
• /
• 1999

This report will introduce the epitome about the subject, HANARO (Hi-flux Advanced Neutron Application Reactor designed by KAERI in early 1995) Utilization Education Training Program Development and Operation, which is one of the nuclear research basic expansion businesses executed from 1999. 12. to strengthen the usage of HANARO. This program consists of the basic reactor experiments program for university students who have specialty of nuclear and other engineering, and the special research education program for faculties from universities and researchers from industrial fields. Principle lessons are reactor operation, radioisotope production, neutron activation analysis, neutron radiography, radiation shield (health physics), nuclear fuel combustion measurement by gamma scanning arrangement, and CNS (Compact Nuclear Simulator) and so on.

• Proceedings of the KAIS Fall Conference
• /
• 2009.05a
• /
• pp.888-890
• /
• 2009

This study presented a lab-scale apparatus for turbidity control in the lakes or reservoirs. Overall, the filamentous mat had a capture efficiency of 70~90% compared with the control group. Generally, the capture efficiency decreased with improved input turbidity flux. However, the attachment and sedimentation were thought to be the main processes for turbidity water retention and removal. Thus, the increase of hydraulic detention time in the mat zone is very important to improve the capture efficiency of the turbidity water.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
• /
• v.3 no.1
• /
• pp.78-85
• /
• 1991

An experimental result for heat transfer of pulsating turbulent pipe flow was presented under the condition of fully developed dynamic regime and uniform wall heat flux. Experiments were performed at following conditions ; Inlet time-averaged Reynolds number varied from 5000 to 11000; The peak pressure fluctuation were 1.3, 2.3 and 3.5 percent of the mean pressure; Pulsating frequency ranged from 53 Hz to 320 Hz The measurements showed that the effect of pulsation on local heat transfer is greater at downstream, in which pulsating source exists, than upstream and the heat transfer rate, averaged over the pipe length, was higher or lower than in an equivalent non-pulsating flow according to the pulsating conditions. In addition, the significant change of heat transfer rate was observed in acoustically resonant conditions, when the pulsating frequency of the flow corresponded to the pipe natural frequency.

• International Journal of Air-Conditioning and Refrigeration
• /
• v.9 no.2
• /
• pp.1-7
• /
• 2001

One of the important applications of a contact melting process is a latent thermal energy storage system owing to its high heat flux and small temperature variation. In some previous works, the split fins have been employed in order to enhance the melting rate. In the present work, the direct contact melting was experimentally investigated using an ice as specimen for both split and non-split fins. It was shown that the contact melting by split fins increases the melting rate compared to that of non-split ones.

• Bulletin of the Korean Chemical Society
• /
• v.34 no.10
• /
• pp.2931-2936
• /
• 2013

This paper presents results for the calculation of transport properties of noble gases (He, Ne, Ar, Kr, and Xe) at 273.15 K and 1.00 atm using equilibrium molecular dynamics (EMD) simulations through a Lennard-Jones (LJ) intermolecular potential. We have utilized the revised Green-Kubo formulas for the stress (SAC) and the heat-flux auto-correlation (HFAC) functions to estimate the viscosities (${\eta}$) and thermal conductivities (${\lambda}$) of noble gases. The original Green-Kubo formula was employed for diffusion coefficients (D). The results for transport properties (D, ${\eta}$, and ${\lambda}$) of noble gases at 273.15 and 1.00 atm obtained from our EMD simulations are in a good agreement with the rigorous results of the kinetic theory and the experimental data. The radial distribution functions, mean square displacements, and velocity auto-correlation functions of noble gases are remarkably different from those of liquid argon at 94.4 K and 1.374 $g/cm^3$.

• Proceedings of the KIEE Conference
• /
• 2000.07b
• /
• pp.870-872
• /
• 2000

This paper deals with the effect of rotor thickness variation and winding method in high torque hybrid Permanent Magnet(PM) step motor. As these parameters vary. The flux distribution in airgap and torque characteristics are influenced, which is related to output power. efficiency and cost. These parameters and characteristic variations were evaluated by using Finite Element Method (FEM) and experiment method. From these results. Characteristic analysis for the optimum design was studied and prototype motor was made to test performance analysis.

• Solar Energy
• /
• v.6 no.2
• /
• pp.15-21
• /
• 1986

In this study, an experimental double diffusive thermohaline system heated from below was constructed and the phenomena of each layer developed in the system were observed. The experiment was performed with the initial salt concentration gradient of $-436.2kg/m^4$ and the net heat flux of approximately $176w/m^2$. An electroconductivity-temperature probe was made and used for the measurements of salt concentration. As the result of this study, it was found that the salt concentration decreased in the bottom mixed layer and increased in the top mixed layer during the experiment while the salt concentration gradient in the diffusive layer unchanged. It was also found that the interfacial boundary layers were due largely to variations in salt concentration rather than temperature.