• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.2
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• pp.101-107
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• 2005

In this paper, optimized operating parameters were found using multi-dimensional engine simulation software (KIVA-3V) and micro-genetic algorithm for heavy duty diesel engine. The engine operating condition considered was at 1,737 rev/min and 57 % load. Engine simulation model was validated using an engine equipped with a high pressure electronic unit injector (HEUI) system. Three important parameters were used for the optimization - boost pressure, EGR rate and start of injection timing. Numerical optimization identified HCCI-like combustion characteristics showing significant improvements for the soot and $NO_X$ emissions. The optimized soot and $NO_X$ emissions were reduced to 0.005 g/kW-hr and 1.33 g/kW-hr, respectively. Moreover, the optimum results met EPA 2007 mandates at the operating point considered.

• Progress in Superconductivity and Cryogenics
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• v.7 no.2
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• pp.27-30
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• 2005

Research and development on superconducting magnetic energy storage (SMES) system have been done to realize efficient electric power management for several decades. Korea Electrotechnology Research Institute (KERI) has developed a 3MJ/750kV A SMES system to improve power quality in sensitive electric loads. It consists of an IGBT based power converter, NbTi mixed matrix Rutherford cable superconducting magnet, and a cryostat with HTS current leads. A computer code was developed to find the parameters of the SMES magnet which has minimum amount of superconductors for the same stored energy, and the 3MJ SMES magnet was designed based upon that. This paper describes the fabrication and experimental results of a 3MJ/750kV A SMES system.

• Journal of the Korean Society of Radiology
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• v.11 no.2
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• pp.87-94
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• 2017

Monte Carlo simulations were used to assess dose enhancement effects for 60-, 90-, 120-, and 150-kV X-rays, and for 6- and 15-MV X-rays. The MCNPX code was used for a computer simulation of the ICRU slab phantom, and gold, gadolinium, and iron oxide (Fe2O3) were employed as dose enhancement agents. In consideration of the buildup region of the incident energy, agent concentrations of 5, 10, 15, and 20 mg/g were inserted on the surface of the phantom at a depth of 5 cm. Based on baseline values obtained in the absence of dose enhancement agents, a quantitative analysis was performed by evaluating depth-dependent changes in the absorbed energy and the dose enhancement factor (DEF). A higher concentration of dose enhancement agents led to a greater dose enhancement effect with iron oxide, gadolinium, and gold in descending order. For kilovoltage (kV) X-rays, as the incident energy was decreased and as the energy became closer to the ionization potential of the atoms in the enhancement agent, the dose enhancement effect increased. In the megavoltage (MV) X-ray range, dose enhancement was higher at 6 MV compared with 15 MV. However, the overall dose enhancements were significantly lower compared to the results obtained with kV X-rays.

• Journal of the Korean Society of Radiology
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• v.17 no.2
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• pp.175-184
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• 2023

Based on the actual shape of the detector and the data provided by the manufacturer, the shape of the detector was implemented through Penelope simulation and applied to the appropriate four-layer thickness based on the efficiency obtained from the measurements. Efficiency calculations to determine the effect of the simulated number of Full Energy Peak Efficiency(FEPE) channels in the detector and the outside contact layer in the crystal on the Full Energy Peak Efficiency were performed for various four-layer thicknesses of 0.3, 0.5, 0.7, 1.0, 1.2, and 1.4 mm using the Penelope Code. When the thickness of the external contact layer was increased by 5 times, the Full Energy Peak Efficiency decreased by about 36% for 59.50 keV, and the Full Energy Peak Efficiency decreased by 10% for 1836. In addition, as it increased by 10 times, the Full Energy Peak Efficiency decreased by about 20% for 59.54 keV, and 7% for 1836.01 keV. The Penelope simulated Full Energy Peak Efficiency channel decreases exponentially with the increase in the four layers. In addition, it was confirmed that the total effect curve was well matched with a relative difference of less than 3.5% in the 0.3-1.4 mm dead layer thickness region. However, it was found that the inhomogeneous dead layer is still a parameter in the Monte Carlo model.

• Journal of radiological science and technology
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• v.31 no.1
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• pp.89-95
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• 2008

The quality correction factor for used beam and qualities is strongly required for clinical dosimetry by TRS-398 protocol of IAEA. In this study the quality correction factors for a commercial plane-parallel ionization chamber in high energy electron beams were calculated by Monte Carlo code(DOSRZnrc/EGSnrc). In comparison of quality correction factor, the difference between this study and TRS-398 were within 1% in 5-20 MeV. In case of 4MeV the difference was 1.9%. As an independent method of determination of quality correction factor this study can be applied to evaluate values in the protocol or calculate the factor for a new chamber.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2006.05a
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• pp.373-376
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• 2006

The ring rolling design for a large-scale Ti-6Al-4V alloy ring was performed with a calculation method and FEM simulation. The ring rolling design includes geometry design and optimization of process variables. The calculation method was to determine geometry design such as initial billet and blank size, and final rolled ring shape. A commercial FEM code, SHAPE was used to simulate the effect of process variables in ring rolling on the distribution of the internal state variables such as strain, strain rate and temperature. In order to predict the forming defects during ring rolling, the process-map approach based on Ziegler's instability criterion was used with FEM simulation. Finally, an optimum process design to obtain sound Ti-6Al-4V rings without forming defects was suggested through combined approach of Ziegler's instability map and FEM simulation results.

• Transactions of Materials Processing
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• v.16 no.3 s.93
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• pp.172-177
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• 2007

The process design for large-scale ring rolling of Ti-6Al-4V alloy was performed by calculation method, processing map approach and FEM simulation. The ring rolling design includes geometry design and optimization of process variables. The calculation method was used to make geometry design such as initial billet and blank sizes, and final rolled ring shape. A commercial FEM code, SHAPE-RR was used to simulate the effect of process variables in ring rolling on the distribution of the internal state variables such as strain, strain rate and temperature. In order to predict the forming defects during ring rolling and the formation of over-heating above $\beta$-transus temperature due to deformation heating, the process-map approach based on Ziegler's instability criterion was used with FEM simulation. Finally, an optimum process design to obtain sound Ti-6Al-4V rings without forming defects was suggested through combined approach of Ziegler's instability map and FEM simulation results.

• Transactions of Materials Processing
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• v.24 no.1
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• pp.5-12
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• 2015

In the current study, fundamental deep drawing characteristics of Ti-6Al-4V alloy sheets were investigated to establish the effect of processing conditions on large size square deep drawn cups. To accomplish this study, FE-simulations (Abaqus) were performed to determine optimum blank size, friction coefficient, the gap between punch and die, etc. The simulated processing parameters were verified experimentally. Based on the FE-simulation results, deep drawing was performed with various blank holding loads and sample sizes. In order to improve the formability of Ti-6Al-4V sheet, various lubricant methods were evaluated. Tensile tests and thickness measurements were conducted on the formed sheets. Processing parameters including blank holding force, lubricants, and optimum blank size, were selected to achieve improved drawing quality. With the optimum processing condition, a $200mm{\times}200mm$ cup was deep drawn successfully.

• Journal of Plant Biotechnology
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• v.41 no.1
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• pp.50-55
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• 2014

Plant-based vaccines possess some advantages over other types of vaccine biotechnology such as safety, low cost of mass vaccination programs, and wider use of vaccines for medicine. This study was undertaken to develop the transgenic maize as edible vaccine candidates for humans. The immature embryos of HiII genotype were inoculated with A. tumefaciens strain C58C1 containing the binary vectors (V662 or V663). The vectors carrying nptII gene as selection marker and scEDIII (V662) or wCTB-scEDIII (V663) target gene, which code EIII proteins inhibite viral adsorption by cells. In total, 721 maize immature embryos were transformed and twenty-two putative transgenic plants were regenerated after 12 weeks selection regime. Of them, two- and six-plants were proved to be integrated with scEDIII and wCTB-scEDIII genes, respectively, by Southern blot analysis. However, only one plant (V662-29-3864) can express the gene of interest confirmed by Northern blot analysis. These results demonstrated that this plant could be used as a candidated source of the vaccine production.

• Wind and Structures
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• v.28 no.6
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• pp.381-388
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• 2019

This paper described the application of Geospatial Analysis in determining mean wind speed, $V_h$ for wind load calculation imposed to electrical transmission tower structural design. The basic wind speed data on available station obtained from Malaysian Meteorology Department is adjusted by considering terrain and ground roughness factor. The correlation between basic wind speed, terrain factor and ground roughness stated in EN-50341-1 is used to obtain the $V_h$ for overhead transmission line elements 50 m above ground. Terrain factor, $k_r$ and ground roughness, $z_0$ in this study are presented by land use types of study area. Wind load is then calculated by using equation stated in design code EN-50341-1 by using the adjusted mean wind speed. Scatter plots of $V_h$ for different $k_r$and $z_0$ are presented in this paper to see the effect of these parameters to the value of $V_h$. Geospatial analysis is used to represent the model of $V_h$. This model can be used to determine possible area that will subject to wind load which severe to the stability of transmission tower and transmission line.