• IE interfaces
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• v.13 no.4
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• pp.668-679
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• 2000

Recently, due to the primary emphasis of environmental problem, the proper selection of the prevention technology systems necessary for Dioxin treatment has been one of the critical issues in the industrial sector. This paper shows how an Analytic Hierarchy Process(AHP) model can be used for assessing the performance of selected prevention technology systems: SDA/BF-SCR, SNCR-SDA/BF, SDA/BF, EP-WS-SCR, ED-WS, and EP-SCR-WS essential for Dioxin treatments. The final results show that SNCR-SDA/BF is the most attractive prevention technology system to use in an incinerator system, followed by SDA/BF-SCR, SDA/BF and EP-WS-SCR. This is consistent with the information that we found with respect to the elements that were taken into consideration. Sensitivity analysis is also provided here.

• Analytical Science and Technology
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• v.31 no.4
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• pp.149-160
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• 2018

A large number of functional living products are being produced for eco-friendly or health-promoting purposes. In the manufacturing process, such products could be adulterated with raw materials with high radioactivity, such as monazite and tourmaline. Thus, it is essential to manage raw materials and products closely related to the public living. For proper management, an accurate radioactivity data of the processed products are needed. Therefore, it is essential to develop a rapid and validated analytical method. In this study, the concentration of the radioactive $^{238}U$ and $^{232}Th$ in building materials (e.g., tile, cement, paint, wall paper, and gypsum board) and living products (e.g., health products, textiles, and minerals) were determined and compared by ED-XRF and ICP-MS. By comparing the results of both methods, we confirmed the applicability of the rapid screening and precise analysis of ED-XRF and ICP-MS. In addition, $^{238}U$ and $^{232}Th$ levels were relatively lower in building materials than in living products. Particularly, $^{232}Th$ content in 6 of 47 living products exceeded (maximum $8.2Bq{\cdot}g^{-1}$) the standard limit of $^{232}Th$ content in raw material ($1.0Bq{\cdot}g^{-1}$).

• Journal of Korea Foundry Society
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• v.19 no.5
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• pp.393-402
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• 1999

The reheating of the billet in the semi-solid state as quickly and homogeneously as possible is one of the most important aspects. From this point of view, an optimal design of the induction coil is necessary. The objective of inductive coil designsi a uniform induction heating over the length of the billet. The effect of coil length, diameter, the gap between coil surface and billet and axial position of the billet on temperature distribution of billet has been investigated. These design parameters have an important effectiveness on the electro-magnetic field. Therefore, in this study an optimal coil design to minimize electromagnetic ed effect will be proposed by defining the relationship between billet length and coil length. In particular, key point in induction heating process is focussed on optimizing the coil design with regard to the size of the heating billet and the frequency of induction heating system. After demonstrating the suitability of an optimal coil design through the FEM simulation of the induction heating process, the results of the coil design are also applied to the reheating process to obtain a fine globular microstructure. Its considered that the reheating conditions of aluminum alloys for thixoforging and a new CAE model of the induction heating process are very useful for thixoforging practitioners including induction heating ones.

• Journal of Korean Institute of Industrial Engineers
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• v.36 no.1
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• pp.59-68
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• 2010

The medical emergency departments are suffering from the crowdness of patients, hence the quality of medical service the patients are receiving are getting poorer. Overcrowding of medical emergency departments may incur the waiting time for the treatment, and the improper treatment in time. For the operational control of the emergency department, the crowding index is commonly used to identify the crowding intensity, with which the operation process is managed, and future process can be expected. In this study the composite crowding index is suggested, in which the trend of inpatients rate, the age and acuity of patients, and resource of ED are considered. The validity of the suggested crowding index is discussed by the regression analysis for the index and the actual number of inpatients, and by the simulation study using the process model and the real data.

• Microbiology and Biotechnology Letters
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• v.17 no.3
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• pp.219-223
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• 1989

Effect of antifoam agents, silicone oil and neolin 302, was investigated on the production of prodnisolone by microbial $\Delta$$^1$-Dehydrogenation of hydrocortisone. The microbial process was conduct-ed by using a pseudo-crystallofermentation. By the hydrophobic-hydrophobic interaction, the steroid crystals aggregated with the antifoam agents. The aggregation resulted in a decrease of total mass transter area of substrate particles which is proportional to the dissolution rate of the solid substrate, and it consequently led to a significant decrease of the bioconversion rate. The bioconversion with neolin proceeded more slowly than with silicone oil. Increase of the concentration of the antifoam agents also yielded a significant decrease of the bioconversion rate.

• Transactions of the Korean Society of Mechanical Engineers B
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• v.25 no.10
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• pp.1365-1372
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• 2001

In the planar flow casting(PFC) process, the conditions of the melt puddle between nozzle and rotating wheel affect significantly the quality and dimensional uniformity of the downstream ribbon. For stable puddle formation, the nozzle is placed very close to the quenching wheel, so the surface-tension and wall-adhesion forces have an important effect upon the fluid flow.\`In this study the planar flow casting process has been mode]ed using the VOF method for free surface tracking. The transient puddle formation from the present analysis shows good agreements with the previous experimental results. Furthermore, the variation of melt temperature and the corresponding cooling rate of the melt have been examined. The present results also show how the melt puddle can be farmed on the rotating substrate, how the melt flows within the puddle, and how the changes of the process variables affect the puddle formation and its corresponding fluid flow and heat transfer behavior.

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.513-516
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• 2008

We have replicated nanopillar arrays using injection molding process of active heating and cooling method by several peltier devices. The injection melding has a high accuracy ed good reproducibility that are essential for mass production at low cost. Conventional molding processes widely use the water-based mold heating and air cooling methods. However, in case of replication for nano-patterned structures, it caused several defects such as air-flow mark, non-fill, sticking and tearing. In this study, periodic nano-scale patterns are replicated by using injection molding with Peltier devices. Porous nano-scale patterns, which have pore diameter range from 120nm to 150nm, were fabricated by using anodizing process. Periodic nano-pore structures ( $20mm\;{\times}\;20mm$) were used as a mold stamp of injection molding. Finally, PMMA with nanopillar arrays was obtained by injection molding process. By using the Peltier devices, the temperature of locally adiabatic molds can be dramatically controlled and the quality of the molded patterns can be slightly improved.

• Journal of the Korean earth science society
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• v.18 no.6
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• pp.464-472
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• 1997

The purpose of training science teachers is to bring up the ideality and the most excellent science teachers whom our society needs. So, teacher training college curriculums of science education should be the ones that will train competent and respectable science teachers who have the technical and practical theory and knowledge through the process of high level academic experiences and activities. Accordingly, the training system and improvement plan for the problems in employment of science teachers in secondary schools should be as follows: 1. The employment examination for teachers should be abolished instead, the system of an apprentice teacher should be brought in, or private schools as well as public schools should bring in employment examination system. 2. With the modification of science teacher training curriculums, the cooperative studies of science major subjects and science education subjects should be strengthened and the connection between real needs of secondary schools and curriculums of secondary school science teacher training should be embodied. 3. Bringing up excellent science teachers should be facilitated through the establishment of administrative and financial aiding system about teacher training college.

• Membrane Journal
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• v.21 no.3
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• pp.270-276
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• 2011

A nascent membrane was prepared by using the solution evaporation method with a solution of sPEEK, EdAn (cross-linking reagent), and PEA (grafting reagent) in DMAc. Then, after the imination and sulfonation process the cross-linked and grafted ion-exchange membrane, CG-sPEEK, was obtained. The sulfonation and imination reactions were confirmed by FTIR analysis. In order to evaluate the possibility of prepared membrane for the use of an ion-exchange membrane in PEMFC, proton conductivity, water uptake and volume change were measured and compared with a commercial membrane, Nafion 115. It was revealed that since the proton conductivity (0.17 S/cm) of prepared membrane were much higher than those of Nafion 115 (0.10 S/cm) the prepared membrane could be used for the ion-exchange membrane in PEMFC. However, the high water uptake (130%) of CG-sPEEK should be reduced for the dimension stability.

• KIPS Transactions on Software and Data Engineering
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• v.9 no.8
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• pp.229-234
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• 2020

This paper presents the design and the implementation of CRESTIVE-DX, a concolic testing tool that distribute the concolic testing process over the embedded target system and the host system for efficient test generation of a target embedded program. CRESTIVE-DX conducts the execution of a target program on the target embedded system to consider possible machine-dependent behaviors of a target program execution, and conducts machine-independent parts, such as search-strategy heuristics, constraint solving, on host systems with high-speed computation unit, and coordinates their concurrent executions. CRESTIVE-DX is implemented by extending an existing concolic testing tool for C programs CREST. We conducted experiments with a test bed that consists of an embedded target system in the Arm Cortex A54 architecture and host systems in the x86-64 architecture. The results of experiments with Unix utility programs Grep, Busybox Awk, and Busybox Ed show that test input generation of CRESTIVE-DX is 1.59 to 2.64 times faster than that of CREST.