• Nuclear Engineering and Technology
• /
• v.50 no.6
• /
• pp.899-906
• /
• 2018

The irradiation performance of $U_3Si$ dispersion fuel in an Al matrix, $U_3Si-Al$, under the Hi-Flux Advanced Neutron Application Reactor (HANARO) design full-power condition of 30 MW was tested for full-power qualification of the fuel. A test assembly was fabricated containing 18 fuel rods made with atomized $U_3Si$ powder manufactured at the Korea Atomic Energy Research Institute. The test assembly was irradiated for 188 full-power operation days in the HANARO subject to the normal fuel-loading scheme and achieved about 60 at% U-235 average burnup and 75 at% U-235 peak burnup. The maximum linear power of the test assembly was 98 kW/m. Nondestructive and destructive postirradiation examinations were conducted. The measured postirradiation examination data were compared with data from previous irradiations and the design criteria required for HANARO fuel. Consequently, it was concluded that in-pile performance was acceptable and fuel integrity was maintained, and the behavior satisfied the fuel design requirements.

• Food Engineering Progress
• /
• v.21 no.3
• /
• pp.215-224
• /
• 2017

Resveratrol was incorporated into various combinations of single- and double-layer nanoemulsions, prepared by self-assembly emulsification and complex coacervation with chitosan, alginate, and ${\beta}$-cyclodextrin, respectively. Resveratrol nanoemulsions were composed of medium-chain trigacylglycerols (MCTs), $Tween^{(R)}$ 80, water, chitosan, alginate, and ${\beta}$-cyclodextrin. The corresponding mixtures were formulated for the purpose of being used as a nutraceutical delivery system. Resveratrol nanoemulsions were obtained with particle sizes of 10-800 nm, with the size variation dependent on the emulsification parameters including the ratio of aqueous phase and surfactant ratio. Resveratrol nanoemulsions were characterized by evaluating particle size, zeta-potential value, stability, and release rate. There were no significant changes in particle size and zeta-potential value of resveratrol nanoemulsions during storage for 28 days at $25^{\circ}C$. The stability of resveratrol in the double-layer nanoemulsions complexed with chitosan or ${\beta}$-cyclodextrin was higher, compared with the single-layer nanoemulsions.

• Korean journal of communication and information
• /
• v.54
• /
• pp.32-57
• /
• 2011

This study examined how the Korean courts have made a balance between rights of school teachers' expression and the public interests derived from regulating their rights for expression in related cases. Under the Korean laws such as National Public Service Law and the Law on Assembly and Demonstration, school teachers are considered as civil servants and basically not allowed to assemble to demonstrate for their own interests. The analysis revealed that in 24 cases from a total of 31 teacher-related court cases, teachers were found guilty in violation of related laws. In deciding whether the teachers' participation on anti-government assembly was guilty or not, the courts put an emphasis on public purpose of their expression, the degree to which their expressions affect the society, and specific contents of their expression. Conclusively, it was found out that in applying the related law, Korean courts tend to overweigh the public interests, rather than the teachers' right to express.

• Bulletin of the Korean Chemical Society
• /
• v.28 no.5
• /
• pp.867-870
• /
• 2007

• Transactions of the Korean Society of Automotive Engineers
• /
• v.18 no.5
• /
• pp.68-75
• /
• 2010

The one of the major problems in the development of PEMFC was regarding to the assurance of sealing on stack. The failure on the sealing creates the problems of fuel leakage, mixing, internal combustion, damage on parts and can be a direct reason for the degrading the efficiency of fuel cell. This paper studies on the analytical approach for improving the contacting pressure distribution on the gasket at the evaluation on the sealing of fuel cell stack. So, the assembly analysis on multi layered fuel cell stack was performed. The research on the simplification of finite element model was performed for three dimensional analysis at the multi layered state. The improved contact pressure distribution was obtained through the case studies on gasket for better sealing. In addition, the number of the cell was determined for the effective analysis and the structural characteristics were evaluated based on this research.

• Journal of the Korean Society of Manufacturing Process Engineers
• /
• v.15 no.2
• /
• pp.1-8
• /
• 2016

Generally, electrical circuits are fabricated as Printed Circuit Boards (PCBs) and mounted on the casing of the product. Additionally, this requires many other parts and some labor for assembly. Recently, molding technology has increasingly been applied to embed simple circuits in plastic casing. The technology is called a Molded Interconnected Device (MID). By using this technology, PCB fabrication can be replaced by molding, and much of the corresponding assembly process for PCBs can be eliminated if the circuit is simple enough for molding. Furthermore, as the improvement of conductive materials and printing technologies of simple electric circuits can be printed directly on the casing part, this also reduces the complexity of the product design and production cost. Therefore, this paper introduces a new MID fabrication process using direct 3D printing technology. Additionally, it is applied to an automotive part of a cruise control switch. The methodology and design are shown.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.13 no.4
• /
• pp.190-196
• /
• 2005

The power steering hose assembly is usually manufactured through the swaging process, which is conducted to connect a hose with metal fittings. In this process the hose is inserted into metal components, the sleeve and the nipple, and compressed in the radial direction by the jaws to clamp the hose with metal components. In case that the clamping force is small, the oil in the hose can leak locally under the severe operating conditions. To confirm the clamping force requirements, the measurement of separation force in longitudinal direction of the hose is usually performed. In this study, the swaging process of a hose is simulated with the finite element method, to investigate the effect of friction coefficient on the separation fDrce. The results interpretations are ffcused on the inner rubber component, and also a formula is proposed to estimate the separation farces with respect to friction coefficients.

• The Korean Journal of Air & Space Law and Policy
• /
• v.32 no.1
• /
• pp.355-384
• /
• 2017

In Korea, a Law on Airport Noise Prevention and Noise Control Area Support has been in effect since 2010. And also, airport noise measures project and residents support project conducted following the Law on Airport Noise Prevention and Noise Control Area Support. However, a Law on Airport Noise Prevention and Noise Control Area Support does not apply to military airfield. Many city residents already complain about military airport noise, but there are no countermeasures. They claim the noise from the military airfield is an intrusion on their lives, and some people brought a class action against the government. In the 20th National Assembly, some congressmen already proposed some legislations that aims to support residents adjacent to the military airfield. Nevertheless, relevant legislations are currently pending at the 20th National Assembly. Legislation preventing aircraft noise and providing support measures is essential to residents life who near by military airfield. At first, this study looked at legislations proposed by congressmen in the 20th National Assembly. And also, this study looked at A Law on the Improvement of Living Environment around the Defence Facilities of Japan. Based on this study, we did an analysis of the problem of legislation and proposed improvement suggestion. I hope so that this study could someday help congressmen make a legislation about military airfield noise. We hope the 20th National Assembly will pass the legislation finally to help the residents who near by military airfield relieve their pain by noise and restore their human dignity.

• Nuclear Engineering and Technology
• /
• v.22 no.1
• /
• pp.66-74
• /
• 1990

The thermal-hydraulic characteristics of the 17$\times$17 OFA (Optimized Fuel Assembly) used in the KNU 7&8 are analyzed and compared with that of the 17$\times$17 SFA (Standard Fuel Assembly) loaded in the KNU 5&6. The thermal-hydraulic characteristics analyzed are minimum DNBR, fuel centerline temperature and exit void fraction at normal operation and design over power transient. Additionally, local linear rod power, which will cause fuel centerline melting, is calculated. The DNBR sensitivity calculations are performed with respect to the reactor operating parameters. COBRA-IV-I code is used for these calculations. The modified W-3 correltion and the drift-flux model are applied for the critical heat flux calculation and the void fraction calculation, respectively. From the calculated results, it has been found that the possibility of DNB occurrence is higher in the OFA than in the SFA. The other hand, the local linear power resulting in fuel centerline moiling of the OFA is nearly equal to that of the SFA.

• Composites Research
• /
• v.34 no.6
• /
• pp.406-411
• /
• 2021

PEM (proton exchange membrane) fuel cells generate only water as a by-product, and thus are in the spotlight as an eco-friendly energy source. Among the various components composing the stack of the fuel cell, research on the bipolar plate that determines the efficiency of the fuel cell is being actively conducted. The composite bipolar plate has high strength, rigidity and corrosion resistance, but has the disadvantage of having a relatively low electrical conductivity. In this study, to overcome these shortcomings, a gas diffusion layer (GDL)-composite bipolar plate assembly was developed and its performance was experimentally verified. The graphite foil coating method developed in the previous study was applied to reduce the contact resistance between the bipolar plate and the GDL. In addition, in order to improve electron path in the stack and minimize the contact resistance between the GDL and the bipolar plate, a GDL-bipolar plate assembly was fabricated using a thin metal foil. As a result of the experiment, it was confirmed that the developed GDL-bipolar plate assembly had 98% lower electrical resistance compared to the conventional composite bipolar plate.