• Journal of the Korea Safety Management & Science
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• v.10 no.3
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• pp.167-181
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• 2008

There are lack of labour and increase in logistics costs due to rapid change in logistics environments and the demand for logistics. The reality is that over spending on logistics costs are getting worse due to lack of logistics standardization. An example will be excessive logistics costs caused by unsatisfactory use of logistics equipments in wholesale markets. The logistics efficiency is falling due to delays in using logistics equipments and standardization. Therefore, there needs standardization of logistics functions and unit of handling in each stage from packing, unloading, storage, transporting, logistics information and needs logistics standardization on equipments, machineries used for the above. Standard unified with standardization is called specification and if standardization is applied broadly in manufacturing or processing, inspection than each process in terms of production can be managed rationally and labour skills will improve and product quality will be evenly maintained and compatability of each part in terms of assembly will be maintained thus materials and labour could be saved thus results in increasing productivity and lowering production costs. Also, if it is applied in industry at state-level then there will be rationalization in consumption in circulation as in purchase of raw materials, sales of products, purchase of products by consumers and contribute in improving compatibility and fair transactions. This paper is aimed to help in first solving factors affecting the most in improving logistic efficiency among unit load system and logistic hollowization, standardizing logistics base, standardizing logistics information. The study conducted surveys on limited companies but hope that in the future the target companies can be divided further into types, industries and conduct more demonstrative analysis.

• Journal of Applied Reliability
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• v.16 no.4
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• pp.338-346
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• 2016

Purpose: The purpose of this research is to improve the reliability of the composite material blades used for the wind power generator, by applying the phased array ultrasonic testing technique out of the many nondestructive test into the blades. Method: The wind power generation composite blades are used, as a case study, in order to evaluate the reliability of the phased array ultrasonic testing technique. Defects that are most likely occurred in the field are injected into the different locations of the three different types of artificial test pieces and then phased array ultrasonic testing technique are applied to evaluate the reliability of its effectiveness. Result: As a result of the analysis of the defect signals by applying the A scan and B scan simultaneously, depth and width of the defect could be obtained. An area of defect was proportional to the amount of energy by color in B scan image. The larger amount of energy, reflected amount of energy was appeared in the order of red, orange, yellow, blue color. Conclusion: The most reliable testing method to detect the defect in composite blades for wind power generation is considered to be the combination of the other destructive testing technique with the phased array ultrasonic testing since the PAUT alone could not detect all range of the defects in the blades.

• Korean Chemical Engineering Research
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• v.48 no.4
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• pp.483-489
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• 2010

An image analysis-based soft sensor is designed and applied to automatic quality classification of product appearance with color-textural characteristics. In this work, multiresolutional multivariate image analysis (MR-MIA) is used in order to analyze product images with color as well as texture. Fisher's discriminant analysis (FDA) is also used as a supervised learning method for automatic classification. The use of FDA, one of latent variable methods, enables us not only to classify products appearance into distinct classes, but also to numerically and consistently estimate product appearance with continuous variations and to analyze characteristics of appearance. This approach is successfully applied to automatic quality classification of intermediate and final products in industrial manufacturing of engineered stone countertops.

• Journal of Industrial Technology
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• v.29 no.B
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• pp.221-228
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• 2009

For a stable supply of electric power, periodical inspection of the electric facilities and repair of the distribution lines are required. In case of any unexpected accidents, looped operation among distribution lines may be necessary in order to supply electricity through the sound lines, separating the faulted lines. As a result of this study, it was found that normal looped operation became impossible when phase difference of the looped distribution lines is more than 3 degrees compared with the voltage supply of the distribution lines. Therefore, for a stable supply of electric power to Chuncheon, it is judged to be desirable that looped operation of the distribution lines coming from the same substation M. Tr Bank shall be performed in principle and in case of looped operation with the substation of different system, looped operation among the lines shall be performed after voltage regulation of the substation M. Tr Bank, maintaining similar voltages and load supply volume in order to avoid phase difference through checking the operation conditions of each substation M. Tr Banks. And when looped operation among the distribution lines is scheduled, voltage regulation schedule has been established so far by calculating maximum supply volume through the transformer of the substation and the maximum load volume through the distribution lines but in the future, looped operation of the distribution lines shall be carried out by removing voltage difference with regulating tap or load of the surrounding transformers, with giving prior notice to the substation operators.

• Journal of the Korean Chemical Society
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• v.22 no.5
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• pp.340-355
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• 1978

Model reactions were often applied in the measuring of the mass transfer coefficient and interfacial area between gas and liquid, which are the most important factors in the design of equipment for gas absorption accompanied with chemical reaction this study, wetted wall column was applied to the sulfite-system among the known model reactions. It was found that one could not ignore the effect of contact time on the determination of mass transfer coefficient and interfacial area. When the reaction rate is very high or very low, the differences of absorption rate would be very large in according to the length of column, that is to the contact time. But the effect of contact time was free about the rate constant $k_2=5.5{\times}10^6m^3/kmol{\cdot}s$, that means the rate of gas absorption become independent upon the hydrodynamics of the equipment. It has shown that instead of steel column could be applied the fine grain-graphite column.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.19 no.3
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• pp.280-287
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• 2009

High-tech microelectronics industry is known as one of the most chemical-intensive industries. In Korea, Microelectronics industry occupied 38% of export and 16% of working employees work in microelectronics industry. But, chemical information and health hazards of high-tech microelectronics manufacturing are poorly understood because of rapid development and its penchant for secrecy. We need to investigate on chemical use and exposure control. We Site-visits to 6 high-tech microelectronics manufacturing company which have cleanroom work using over 1,000kg organic solvents (5 semi-conductor chips and its related parts company, 1 liquid crystal display (LCD)). We reviewed their data on chemical use and ventilation system, and measured TVOCs (Total Volatile Organic Compounds) and carbon dioxide concentration. All cleanroom air passed through hepa filters to acheive low particle levels and only 1 cleanroom uses carbon filters to minimize the organic solvents exposures In TVOC screening test, Cleanroom for semi-conductor chips and its related parts company with laminar down flow system (e.g. class 1~100) showed nondetectable level of TVOCs concentration, but Cleanroom for liquid crystal display (LCD) with conventional flow system (e.g. class 1,000~10,000) showed 327 ppm as TVOCs. Acetone concentration in cleanroom for Jig cleaning, LC Injection, Sealing processes were 18.488ppm (n=14), 49.762 ppm (n=15), 8.656 ppm (n=14) as arithmetric mean. Acetone concentration in cleanroom for LCD inspection process was 40ppm (n=55) as geometric mean, where the range was 7.8~128.7ppm and weakly correlated with ventilation rate efficiency(r=0.44, p<0.05). To control organic solvents in cleanrooms, chemical and carbon filters should be installed with hepa filters. Even though their volatile organic compounds concentration was not exceed to occupational exposure limits, considering of entrance limited cleanroom environment, long-term period exposure effects and adverse health effects of cleanroom worker need further reseach.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.19 no.6
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• pp.154-159
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• 2018

Intentional releases occur frequently during maintenance in gas supplying companies, which may result in unpleasant odors, and the possible mistaken belief of a gas accident. Therefore, this study developed a chemical process for effective odorant removal in natural gas using an active chemical that is released intentionally during maintenance and inspection. To develop an effective treatment process for removing the odorant from released natural gas, the effluent concentrations of the odorant in the released gas were measured after a chemical oxidation reaction with a sodium hypochlorite solution in a compact gas scrubbing equipment newly devised in this study. The device was based on a mixed gas vent after the solution inject odorant in the gas through the energy of the venting gas. The cascade combination of a venturi pipe and mixing chamber was developed to remove the odorant effectively from the purposely-released natural gas using an oxidative reaction between the mercaptan compounds (odorant) and the sodium hypochlorite solution. On the other hand, the developed method could be applied limitedly to a relatively small gas release from a low-pressure source. Further studies will be needed to apply the developed process to a large-scale gas release from a high-pressure source.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.379-388
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• 2016

There are various system defects from weapons manufacturing due to the numerous production processes and various production environments. The first kind of defect is patent defects, which can be detected by visual inspection, functional testing, and existing quality control procedures during the manufacturing process. The second kind is latent defects, which cannot be detected though existing quality management approaches because of the complexity of the system and manufacturing process. To minimize the initial defect problems, environmental stress screening (ESS) is needed to detect the defects, remove them, and improve the product conditions based on the environmental stress conditions of temperature and vibration. We implemented a tool for quantitative ESS effectiveness analysis and profile design automation based on MIL-HDBK-344 and verified it using six scenarios with different temperature stress, vibration stress, and test designs.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.16 no.10
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• pp.6751-6758
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• 2015

The Special Act on Safety Control for Infrastructure was enacted in 1995 to contribute to ensuring the public safety and welfare improvement of Korean people. In addition, the FMS has been developed and operated to manage facilities effectively. However, several problems of the FMS have also occurred. Thus, this study aimed to analyze the FMS and related systems scrutinizingly to suggest improvement directions such as (1) extension of the FMS into the national facility information management system including small-size facilities other than Types 1 and 2 facilities, (2) development and promote standardized inspection and diagnosis systems as per facility type, (3) development of the database utilization system including decision making support function for management body, and (4) providing the FMS performance improvements and stable operating environment utilizing latest information technologies. If the improvement directions suggested in this study are adopted, they can improve services for Korean people by providing facility safety and maintenance work parties with optimum information services.

• Journal of the Korean Society for Heat Treatment
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• v.7 no.1
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• pp.25-34
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• 1994

To investigate the effect of austenitizing tempratures on the mechanical properties and corrosion resistance of 0.19%C-13.6%Cr martensitic stainless steel, the changes in martensitic trasformation temperatures, mechanical properties and anodic polarization curve were examined after changing the austenitizing temperatures and tempering temperatures. On increasing heating rate at the same austenitizing temperatures, $A_s$, $A_r$ and $M_s$ increased. And the $M_s$ temperature showed to be decreased with increasing austenitizing temperature. With increasing tempering temperature up to $500^{\circ}C$, strength, hardness and impact value were not changed remarkably, on the other hand the tensile strength and hardness decreased and impact value increased after tempering above $550^{\circ}C$ owing to the $M_{23}C_6$ carbide precipitation. The abrupt decrease in elongation at the tempering temperture of $500^{\circ}C$ proved to the precipitation of $M_7C_3$ carbide. The effect of austenitizing temperature on the mechanical properties of the tempered specimen showed to be decreased in impact value and elongation at the austenitizing temperature of $1150^{\circ}C$. At low tempering temperatures the corrosion resistance of the tempered specimen was not changed obviously with increasing tempering temperature. On the other hand, the resistance decreased above the tempering temperature of $600^{\circ}C$ due to the precipitation of $M_{23}C_6$ carbides. The corrosion resistance showed to be improved with increasing the austenitizing temperature owing to the dissolution of carbides.