• Proceedings of the Korean Institute of Building Construction Conference
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• 2009.05b
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• pp.81-85
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• 2009

This study was to execute the basic property evaluation of recycled sand which produced by the sand flux device in order to evaluate the performance of differences between small large sand flux device. As a result, this study has found out that the recycled sand after passing the sand flux device had excellent quality characteristics compared with the One before passing the device. In additional experiment On the basic material properties, this study showed a tendency to improve the quality and performance significantly in case of fineness modulus, absolute surface dried density, 0.08mm sieve throughput, volume of clay lumps, and content of organic foreign matter. In conclusion, it was considered as various quality performances of recycled sand were improved through the production stage of prototype.

• Proceedings of the Korea Institute of Fire Science and Engineering Conference
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• 2008.11a
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• pp.262-269
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• 2008

Chemical products have had an favorable influence on our everyday life, and contributed very much to the development of human culture. According to the rapid change of industry and the development of scientific technique the using chemical products are increasing more and more. Chemical products can have any hazardous property such as flammability or explosiveness. There are occurring many accidents in the international trade due to the different classification and labelling of chemicals produced in various countries. The main purpose of this work is the development of global standard test methods for the chemicals, and the classification and labelling in building block approach by means of the basic technical data. Oxidizing solids, combustible solids, spontaneously combustible materials, water-prohibitive materials, flammable liquids, self-reactive materials and oxidizing liquids have been tested. The results have been classified according to the hazard material safety regulation and the UN regulation, and summarized in a data-base.

• Proceedings of the KSR Conference
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• 2011.10a
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• pp.649-655
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• 2011

In this paper, the content to carry out the modal testing and to analyze the data as the target of the main transformer installed on KTX is mentioned. The main transformer for KTX is a structure which is over 10 Ton. For the possibility to occur a stress concentration phenomenon exists, the dynamic durability of the system is experimentally needed to understand. To do this, we obtained the vibration data using an accelerometer, an impact hammer, a measuring instrument and gained the frequency response function of the main transformer based on the acquisition data. In this content, when the theoretical model for structural analysis should be established, we think it will be used for the property verification of analytical model. Also, we expect that the measured and analysed data will offer basic research material to maintain the system and diagnose the condition by monitoring the natural frequency of the main transformer for KTX periodically.

• Proceedings of the Korea Concrete Institute Conference
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• 2001.05a
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• pp.757-762
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• 2001

CFT concrete has high flowing, high strength and resistance to material separation to use skyscraper structure. It is considered that concrete could fill the lower part of Diaphragm up. This kinds of CFT concrete hardly apply to building below 20 stories. Using the common use strength concrete to building below 20 stories brings to reduce construction cost. This concrete is needed that valid fluidity and packing ability with unit cement content as common use strength concrete. Offering a fundamental data and proportioning in CFT concrete of below 20 stories, it is executed basic property test, analysis of proportioning and mock up test.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2001.04a
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• pp.1085-1088
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• 2001

The process of styrofoam pattern that has been used for material of press die pattern depends chiefly on handwork. Laser manufacturing system developed to increase precision and efficiency of process that is also able to convert the design easily. Applying the RP(rapid prototyping) concept reversely, the unnecessary part of section is vapored away by heat source of laser beam after converting 3-D CAD model into cross-sectional shape information. Laser beam is line-scanned in plane specimens to measure the depth and width of cut, surface roughness, cross-sectional shape as converting laser power, scanning speed, cutting gas pressure. With these basic data, plane surface, inclined surface, hole, outer contour trimming process is experimented and optimum condition are obtained. In plane and inclined surface experiments, 15W laser power and 50mm/s scanning speed make superior processing property and 30W, 10mm/s make processing efficiency increase in trimming process. With these results, simple patterns were manufactured and the possibility of applying laser manufacturing system to styrofoam pattern was convinced.

• International Journal of Human Ecology
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• v.9 no.1
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• pp.41-51
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• 2008

A rapidly aging Korean population highlights the importance of investigating the actual state and needs of clothing for the elderly to provide basic information for a future senior industry. This paper surveyed clothing purchasing behaviors. The sample of this survey consisted of 210 females aged 55 over who live in Dajeoun and Nonsan. The data were analyzed by using SPSS. The major findings are as follows. First, most elderly women have bought the ready-made clothes in local markets. Second, the major consideration of clothing purchasing behavior was the possibility of outdoor wearing and color. They were satisfied with ready-made clothes because of the convenience to buy, design, and the necessity of the clothing brands for aged people. Third, they preferred pure cotton or mixed cotton even though they possessed the mixed cotton or synthetic fiber in clothing materials. Respondents preferred the feeling, heat-retaining property, and absorptiveness in textiles. The result indicates the demand for various material applications of functional textiles for elderly women.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.14 no.4
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• pp.14-20
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• 2015

Molding technologies for plastic microstructures have been extensively investigated during the last two decades, and theoretical and numerical studies on the micro molding process have provided efficient tools for the development of such molding technologies. In this paper, we present a review of numerical simulation methods for the micro molding process. Basic models for a description of the material property, governing equations of the flow and heat transfer during the molding process, and numerical methods will be described. Particularly, numerical simulations for micro injection molding and hot embossing processes will be presented, and their main features noted and compared to those for conventional molding processes.

• KIEE International Transactions on Electrophysics and Applications
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• v.3C no.4
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• pp.146-154
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• 2003

This paper describes various characteristics of the new compounds for cable jackets and model cables advanced in waterproof performance in order to essentially solve the problems of underground (URD) distribution class power cable failures. Several compounds were manufactured by the inclusion of additives to base resins available in Korea and tested for basic property, mechanical and electrical characteristics. Two model cables were created by using the compounds determined in the test as being the most appropriate for new structured model cable jacket material. The waterproof performance and mechanical strength of the new cable jackets were verified by applicable tests. As a result, MDPE and LLDPE compounds were superior as cable jackets in both mechanical and electrical characteristic aspects when compared with conventional PVC. In addition, the model cables composed of the new compounds based on MDPE showed good quality results in the water permeability test.

• Journal of the Korean Geophysical Society
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• v.6 no.2
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• pp.107-119
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• 2003

The behavior of pore pressure and effective stress in a highly saturated sand bed under variations in the water pressure in its surface were investigated to determine the mechanism of the collapse of hydraulic structures during flooding or when attacked by storm waves. The vertical, one-dimensional model was used as a basic model to clarify the effect of water pressure variation on only to the vertical direction. The theoretical results show that a sand bed under variations of water pressure is weakened by an increase in excess pore pressure and that under certain conditions the sand bed will liquefy. Although many factors related to water pressure variation and property of the material determine this phenomenon, the mist important factor seems to be the small amount of air present in the sand bed. The theoretical results reported are verified by experiments.

• Transactions of the Society of Information Storage Systems
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• v.3 no.4
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• pp.178-182
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• 2007

Topology optimization methods are classified into two methods such as the density method and the homogenization method. Those methods need to consider relationships between the material property and the density of each element in a design domain, the relaxation of the design space, etc. However, it is hard to apply on some cases due to the complexity to compose the design objective and its sensitivity analysis. In this paper, a modified topology optimization is proposed to assist designers who do not have mathematical or theoretical background of the topology optimization. In this study, optimal topology of structures can be achieved by the sequential design of experiment (DOE) and the sensitivity analysis. We conducted the DOE with an orthogonal array and the sensitivity analysis of design variables to determine sensitive variables used for connectivity between elements. The modified topology optimization method has advantages such as freedom from penalizing intermediate values and easy application with basic DOE concept.