• Proceedings of the Korean Radioactive Waste Society Conference
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• 2016.05a
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• pp.17-18
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• 2016

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.04a
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• pp.317-322
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• 2004

This paper deals with a prediction method of tool life in view of the reliability assessment. In this study, the flank wear was studied among multi-factors deciding the tool wear state. Firstly, tool lift was predicted by correlation between flank wear and cutting time, based on the extended Taylor tool life equation of turning data, including parameters of cutting speed, feed rate, and cutting depth. Secondly, each of cutting conditions of endmilling was equivalently converted to apply ball endmill data to the extended Taylor equation. The web-based reliability prediction program for tool lift is being developed as one of reliability assessment programs to for the machine tools.

• Transactions of the Korean Society of Machine Tool Engineers
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• v.14 no.3
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• pp.1-7
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• 2005

The prediction for tool life is one of the most important factors for increasing reliability, stability, and productivity of manufacturing system. This paper deals with a tool life prediction method in view of reliability assessment for cutting tools. In this study, flank wear was focused among multi-factors deciding the tool wear state. First, tool life was predicted by correlation between flank wear and cutting time, based on the extended Taylor tool life equation of turning, including parameters of cutting speed, feed rate, and cutting depth. Second, each of cutting conditions of end-milling was equivalently converted to apply ball end-mill data to the extended Taylor equation. The web-based prediction program for tool life was developed as one of reliability assessment programs for machine tools.

• Proceedings of the Korean Society of Machine Tool Engineers Conference
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• 2004.10a
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• pp.369-374
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• 2004

Web-based analysis programs for reliability assessment of machine tools were developed in this study. First, the reliability data analysis program was developed to search for failure rate using failure data and reliability test data of mechanical part. Second, failure mode analysis was developed through performance tests like circular movement test vibration test for machine tools. This analysis program shows correlation between failure mode and performance test result. Third, tool life was predicted by correlation between flank wear and cutting time, using the extended Taylor tool life equation in turning data and the equivalently converted equation in order to apply ball endmill data to Taylor tool life equation in milling data. All the information related to input and result data can be stored in theses programs.

• Journal of the Korean Institute of Gas
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• v.15 no.5
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• pp.42-49
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• 2011

To achieve the safety management of an industry by using practical consequence analysis, parameters affecting damage area and financial loss by gas release accident were analyzed at pressure vessels containing flammable gas. As a result, the total financial loss cost was largely effected by the business interruption cost, and it was considered for equipment type and materials, process properties, and circumstances. Also, the consequences of the financial loss must be practically used more than the consequences of the damage area in industry.

• Journal of Welding and Joining
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• v.33 no.1
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• pp.49-53
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• 2015

An experimental study was conducted to investigate the effect of carbon nanotubes on the zinc corrosion resistance of sealing layer formed on the Tungsten Carbide spray coating. Using the nanotubes, a sealing agent in the form of solid-liquid suspensions was made and applied to the surface of spray coating. A series of experiments, consisted of three stages such as preparation of test piece, molten-pot immersion test, and evaluation of micro structure, were undertaken to demonstrate complicated interaction existing between zinc ions and sealing layer containing the nanotubes. Experimental results showed newly developed sealing layer were less susceptible to corrosion and thus coated layer was well protected even in the case of 10 days exposure. Comparison of the micro structure after molten pot test also indicated that carbon nanotubes still remained in the matrix and organized more reliable frame work constituted with boron nitride and chromium compound. It was revealed that carbon nanotubes in the sealing layer played positive role to enhance zinc corrosion resistance in the perspective of both fibrous structure and inherent chemical stability.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.19 no.3
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• pp.275-283
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• 2007

An experimental study was conducted to investigate the effect of the morphology of CNT (Carbon Nanotube) on the thermal conductivity of suspensions. The effective thermal conductivities of the samples were measured using a steady-state cut bar apparatus method. Enhancements based on the thermal conductivity of the base fluid are presented as functions of both the volume fraction and the temperature. Although functionalized SWNT (Single-Walled Carbon Nanotube) produced more stable and homogeneous suspensions, the addition of small amounts of surfactant to suspensions of 'as produced' SWNT demonstrated a greater increase in effective thermal conductivity than functionalized SWNT alone. The effective thermal conductivity enhancement corresponding to 1.0% by volume approached 10%, which was observed to be lower than expected, but more than twice the values, 3.5%, obtained for similar tests conducted using aluminum oxide suspensions. However, for suspensions of MWNT (Multi-Walled Carbon Nanotube), the degree of enhancement was measured to be approximately 37%. It was postulated that the effect of clustering, resulting from the multiple heat-flow passages constituted by interconnecting neighboring CNT clusters, played an important role in significant enhancement of effective thermal conductivity.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.11 no.2
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• pp.193-204
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• 1999

Performance of a variable-speed, roller-type vane compressor was evaluated at low evaporating temperature. First, an experimental investigation was conducted to examine the performance variation as functions of both outdoor temperature and rotating speed. For this purpose, a typical heat pump was implemented as a test apparatus to measure mass flow rate and power input. Secondly, computational investigations corresponding to the heat pump test conditions were performed to predict compressor performance using ORNL Map-Based compressor model. Results obtained from the heat-pump experiments showed that both mass flow rate and power consumption were sensitively dependent on both evaporating temperature and compressor speed as was predicted from the computational results. From the comparisons of both experimental and computational results, it was well recognized that the ORNL model was subjected to larger error in the accuracy of prediction as outdoor temperature decreased. When the outdoor temperature was above $-5^{\cire}C$, errors of predicted values corresponding to both mass flow rate and power consumption were estimated as $\pm$10% and $\pm$ 15%, respectively. Finally, it is suggested that the ORNL model needs to be re-evaluated if compressor map data tested below $-5^{\cire}C$(in evaporating temperature) are available.

• Korean Journal of Air-Conditioning and Refrigeration Engineering
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• v.18 no.3
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• pp.231-239
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• 2006

An experimental investigation of a Reversible Loop Heat Pipe (RLHP) was conducted to determine the operating limits and performance characteristics as functions of the thermophysical parameters, the heat input, and the cooling intensity. Variations in both temperature and heat transport capacity were measured and analyzed in order to accurately evaluate the transient operating characteristics. In addition, the maximum heat transport as a function of the mean evaporator temperature, the ratio of heat transport to heater input power as a function of the mean evaporator temperature, and the overall thermal resistance as a function of the overall heat transport capacity were examined as well. Results indicated that the cooling intensity played an important role on the operating characteristics and performance limitation. The maximum heat transports corresponding to cooling intensity $72W/^{\circ}C$ and $290W/^{\circ}C$ were 446 W and 924 W, respectively. Also, observation of the startup characteristics indicated that the mean evaporator temperature should be maintained between $40^{\circ}C$ and $60^{\circ}C$, and overall thermal resistance were measured as $0.02^{\circ}C/W$.

• Fire Science and Engineering
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• v.28 no.5
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• pp.14-22
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• 2014

Hydrocarbon fires and explosions in petrochemical plants have occurred repeatedly every year. But domestic law of fire protection system is insufficient for the worst case scenario. In this study, we analyzed domestic and foreign standards of fire protection system in petrochemical plants and surveyed firefighting equipment of 32 petrochemical plants in ulsan petrochemical complex. Finally, it is necessary to design fire water supply based on the worst case scenario in petrochemical plants and firefighting equipment such as fixed water spray system, elevated monitor nozzle, water curtain, large amount foam monitor system should be installed for the worst case scenario in petrochemical plants.