• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2008.05a
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• pp.370-373
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• 2008

It is known that the temperatures of die, punch, holder and punch pad need to be kept different to get better formability in Mg sheet forming processes. Heating and cooling channels are usually equipped in each tool to assign different temperature. This study focused on the optimal design of the heating and cooling channels for a cross-shaped deep drawing die set. While the die and blankholder were heated to and kept at $250^{\circ}C$ by using heat cartridges, the punch and punch pad were kept at much lower temperature than that of the die and blankholder by water circulating through cooling channels. All the approaches were done by numerical analyses, aiming to maximize the cup height and to minimize the punch corner radius without any failure.

• Journal of the Korean Institute of Electrical and Electronic Material Engineers
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• v.30 no.10
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• pp.677-682
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• 2017

Lamination is used extensively in various industries. The type of lamination applied to the material depends on the precision level required, which varies for materials needed for everyday use, materials used in high-tech industries, and processes employed to fabricate finished products. Especially in hot lamination, the distribution of the surface temperature of the heating roller is very important to avoid the generation of internal bubbles and ensure flatness of the attached materials, and thus maintain a good standard of quality and productivity. In this study, we have developed a system to monitor the surface temperature of the heating rollerby applying a heterogeneous controller and a non - contact temperature sensor. This monitoring system accurately measures the surface temperature of the heating roller and applies the RS485 MODBUS communication method for easy expansion. Using this system, a laminated prototype was fabricated, and its efficacy for non-contact temperature sensor calibration, Ethernet IP communication, stoppage of the heating roller, and determination of temperature distribution with rotation was examined for its potential usage in industries.

• KIEAE Journal
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• v.10 no.6
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• pp.139-144
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• 2010

The demands are increasing for the efficient heating and cooling system and thermal comfort environment because of changes in climate and environment, and deterioration of buildings and facilities can cause education budget to increase. So the study to apply heating and cooling system to university is urgently needed to improve an optimum energy saving system, educational environment and convenience of maintenance. For this reason, we selected a university campus in Seoul then came to understand the current situation and found some problems. We drew alternatives from comparative analysis of them. It selects representative building and carries out economic analysis to evaluate characteristics of energy consumption and economics on each type of heating and cooling system. As a result we drew the optimum system from those processes as previously stated. We studied 3 available systems, absorption chiller, EHP(Electric Heat Pump) and GHP(Gas Engine Heat Pump). According to LCC analysis suppose that the value of EHP is 1, it came out that the value of absorption chiller is 1.5 and the value of GHP is 2.2. This study, suggesting the optimum heating and cooling system, will support educational and research activities furthermore effect to maximize energy efficiency. Ultimately it is expected that it will contribute to make eco-friendly Green Campus.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.699-704
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• 2002

The pipe with a long-neck flange is widely used in power plants, chemical plants, and shipbuilding companies. New the pipe with a long-neck flange is manufactured by welding a thick flange to a pipe. But this long-neck flange pipe has some deflects in the welding region such as unfitting and local thermal fatigue, which weaken the strength around the neck of the flange. Moreover, after welding the flange, the contacting surfaces of the flange have to be machined flat. So, that is uneconomical. Therefore, to solve the above problems of the long-neck flange pipe, a new process, which has no defects around the flange neck, is required. In this study, three forming processes are suggested to get an enhanced long-neck flange. First suggested process consists of conical terming and flange forming. Second and third suggested processes consist of the bulging of a long pipe locally heated by induction coils and the flange forming. The differences between second and third suggestions are the thickness and local heating area of the pipe. That is, the thickness of the initial pipe of third suggestion is larger than that of the final product, and the local heating area is smaller than that of second suggestion. These three suggestions fur forming a long-neck flange are simulated by FE analyses with a commercial cede DEFORM 2D. Especially, the theoretical result of FE analysis on the first suggestion fur forming a long-neck flange is verified by the experiment with aluminum 6063 pipes. From the theoretical and experimental results, it is concluded that three suggested processes are very useful in order to manufacture the pipe with a long-neck flange without any deflects.

• Journal of the Korean Society for Precision Engineering
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• v.19 no.8
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• pp.212-219
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• 2002

The pipe with a long-neck flange is widely used in power plants, chemical plants, and shipbuilding companies. Now the pipe with a long-neck flange is manufactured by welding a thick flange to a pipe. But this long-neck flange pipe has some defects in the welding region such as unfitting and local thermal fatigue, which weaken the strength around the neck of the flange. Moreover, after welding the flange, the contacting surfaces of the flange have to be machined flat. So, that is uneconomical. Therefore, to solve the above problems of the long-neck flange pipe, a new process, which has no defects around the flange neck, is required. In this study, three forming processes are suggested to get an enhanced long-neck flange. First suggested process consists of conical forming and flange forming. Second and third suggested processes consist of the bulging of a long pipe locally heated by induction coils and the flange forming. The differences between second and third suggestions are the thickness and local heating area of the pipe. That is, the thickness of the initial pipe of third suggestion is larger than that of the final product, and the local heating area is smaller than that of second suggestion. These three suggestions for forming a long-neck flange are simulated by FE analyses with a commercial code DEFORM 2D. Especially, the theoretical result of FE analysis on the first suggestion for forming a long-neck flange is verified by the experiment with aluminum 6063 pipes. From the theoretical and experimental results, it is concluded that three suggested processes are very useful in order to manufacture the pipe with a long-neck flange without any defects.

• Spatial Information Research
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• v.17 no.3
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• pp.319-328
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• 2009

The growth of sensor and wireless communication technology enable us to monitor the status of things in real-time. There are many attempts to apply the real-time monitoring in various fields. Especially, the real-time monitoring in facility management fields has attracted much attentions recently. But it is difficult to apply recent technologies including sensor, wireless communication and Geospatial information technologies, etc, to the real situation directly. One of the reasons is that facility managers who are familiar with existing processes may resist the change induced by new technologies. So it is necessary to close the gap between new technologies and existing processes by improving the existing processes prior to putting them in the field. In this paper, we suggest the management process improvement focused on the district heating facilities.

• Journal of Nutrition and Health
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• v.36 no.10
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• pp.1071-1082
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• 2003

The objective of this study was to evaluate and improve the microbiological quality of HACCP application in school foodservice operations. The microbiological quality of foods and utensils were evaluated two times at each critical control point (CCP) with 3M petrifilm in five Daegu elementary schools. Two processes were evaluated: Heating process and after-heating process. The CCPs of the heating process were receiving, cooking and serving temperatures. The CCPs of the after-heating process were personal hygiene, cross contamination avoidance and serving temperature. After the first experiment, 31 employees of five schools were classroom educated, trained on-site, and pre- and post-tested on HACCP-based sanitation with the goal of improving the microbiological quality of the foodservice. Scores representing knowledge of holding, thawing, washing, food temperature, sanitizing and food-borne illness increased after education. In the heating process, internal food temperatures in the first and second experiments were higher than 74$^{\circ}C$, the holding temperature in the first experiment was less than 6$0^{\circ}C$. In the second experiment, the serving temperature improved to a satisfactory level. The microbiological quality in the second experiment improved by decreasing the time from cooking to serving. In the after-heating process, the ingredients were boiled before being cut in the first experiment. In the second experiment, ingredients were cut before being boiled, improving microbiological quality. Also in the second experiment, cooking just before serving food improved its microbiological quality through time-temperature control. These results strongly suggest it is essential to measure microbiological quality regularly and to educate employees on HACCP continuously, especially time-temperature control and cross contamination avoidance in order to improve foodservice quality.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.1
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• pp.100.2-100.2
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• 2012

We have investigated excitation processes of the 3-micron bands of $CH_4$, $C_2H_2$, and $C_2H_6$ over the auroral regions of Jupiter including particle bombardments, Joule heating, scattering of solar radiation, and possible chemiluminescence. We also considered possible LTE or Non-LTE conditions of these processes. We constructed particle precipitation models including $H_2$, He, H, and the hydrocarbon molecules for the atmosphere of the auroral regions. We present preliminary results from these models, and comparisons of the model results with spectroscopic observations in the 3 micron wavelength range of Jupiter.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.22 no.12
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• pp.828-836
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• 2010

The drying is a process that involves coupled and simultaneous heat and mass transfer. When a wet solid is subjected to thermal drying, two processes occur simultaneously. Drying is classified according to heat transfer characteristics in terms of conduction, convection and radiation. In thermal drying, radiation is easier to control than conduction and convection drying and involves a relatively simple structure. In this study, we measured energy consumption, surface hardness of paint and surface gloss with variation of surface temperature of drying materials and drying time. Drying characteristics and energy consumption between heating panels and hot air heating have been presented. The present study shows that a dryer using heating panels is more effective than a hot air dryer from the viewpoint of energy conservation. The hot air dryer, however, was not optimized and more studies on various parameters related to drying will need to be investigated for definite comparison of drying characteristics of the dryers. The result, even if limited, would present the effective availability of paint drying.

• Journal of ILASS-Korea
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• v.3 no.3
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• pp.49-59
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• 1998

The vaporization characteristics and spray combustion processes in the high-pressure environment are numerically investigated. This study employ the high-pressure vaporization model together with the state-of-art spray submodels. The present high-pressure vaporization model can account for transient liquid heating, circulation effect inside the droplet forced convection, Stefan flow effect, real gas effect and ambient gas solubility in the liquid droplets. Computations are carried out for the evaporating sprays, the evaporating and burning sprays, and the spray combustion processes of the turbocharged diesel engine. Numerical results indicate that the high-pressure effects are quite crucial for simulating the spray combustion processes including vaporization, spray dynamics, combustion, and pollutant formation.