• Nuclear Engineering and Technology
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• v.51 no.5
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• pp.1365-1372
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• 2019

The effects of Y and Ti on the microstructure stability and tensile properties of the reduced activation ferritic/martensitic steel have been investigated. The addition of Y and Ti affected the prior austenite grain size due to the pinning of the inclusions. Ti addition of 0.008 wt% to the steel was intended to promote the precipitation of nano-sized carbides with a high resistance to coarsening. 8Ti14Y exhibited a higher yield strength and a lower DBTT than the other alloys due to the fine grain size and additional precipitation hardening by (Ti, Ta)-rich MX. After thermal exposure at $550^{\circ}C$ for 1500 h, yield strength was dropped significantly in exposed 0Ti13Y. On the contrary, a lower reduction of YS was observed in 8Ti14Y. The $M_{23}C_6$ in 0Ti13Y and 8Ti14Y and MX in 25Ti14Y and 39Ti15Y coarsened seriously during ageing, which could be responsible for the reduction of the tensile properties of alloys.

• Nuclear Engineering and Technology
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• v.51 no.6
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• pp.1589-1595
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• 2019

In this paper, the CLAM steel strengthened by micro-scale Y-Zr-O was prepared by vacuum induction melting followed by electroslag remelting (VIM-ESR). Yttrium (Y) and zirconium (Zr) were easy to aggregates into massive yttrium-zirconium-rich inclusions in the steel melted by vacuum induction melting (VIM), which would interrupt the continuity of the matrix and reduce the mechanical properties of steel. Micron-sized Y-Zr-O inclusions would be produced with the removal of original blocky Y-Zr-rich inclusions and the submicron-sized inclusions smaller than $0.2{\mu}m$ could be retained in the steel. The small grain size and the better refinement and distribution uniformity of Y-Zr-O inclusions after remelting would be responsible for the better yield strength and toughness. For VIM-ESR alloy, the ultimate tensile strength is 749 MPa and the yield strength is 642 MPa at room temperature, meanwhile they are 391 MPa and 367 MPa at $600^{\circ}C$, respectively. Meanwhile, the ductile-brittle transition temperature (DBTT) reduced from $-43^{\circ}C$ (VIM) to $-76^{\circ}C$ (VIM-ESR).

• Nuclear Engineering and Technology
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• v.51 no.1
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• pp.221-227
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• 2019

One of the important requirements for the application of reduced activation ferritic/martensitic steel is to retain proper mechanical properties in irradiation and high temperature conditions. In order to simulate the impact toughness with the effect of temperature and irradiation, a simulation model based on energy balance method consisted of crack initiation, plastic propagation and cleavage propagation stages was established. The effect of temperature on impact toughness was analyzed by the model and the trend of the simulation results was basicly consistent with the previous experimental results of CLAM steels. The load-displacement curve was simulated to express the low temperature ductile-brittle transition. The effect of grain size and inclusion was analyzed by the model, which was consistent with classical experiment results. The transgranular-intergranular transformation in brittle materials was also simulated.

• Journal of Korean Society of Industrial and Systems Engineering
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• v.45 no.3
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• pp.66-77
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• 2022

Digitization and automation technologies have rapidly maximized productivity and efficiency in all industries over the past few decades. Construction automation technology has either stagnated over the same period or has not kept pace with overall economic productivity. According to the research studies up to now, the output of concrete structures using coarse aggregates (8mm or more) is very limited due to the limitations of equipment and materials. In this study, information on the development process of 3DCP equipment that can print concrete structures with the printing width (100 mm or more) and printing thickness (30 mm or more) using a 3DCP material mixed with coarse aggregate (8 mm or more) is provided. To verify the performance of the developed 3DCP equipment, experimental data are provided on output variables, the number of layers, and the inter-layer printing time interval. The evaluation and verification data of various mechanical properties (compressive and splitting tensile strength) of printed materials using coarse aggregates are provided.

• Proceedings of the Korean Institute of Building Construction Conference
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• 2020.11a
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• pp.175-176
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• 2020

As the concrete pouring work relies on manual work, there is a lot of room for automated equipment development. In this study, as a basic study on the development of an automated system for pouring concrete, the trend of patent applications by year, country and detailed technology was investigated. Related technologies were classified into screed automation, CPB automation, and concrete pouring integrated system to analyze patent application trends. As a result, since 1999, patent applications have been steadily in progress, repeating increases and decreases in Japan, Korea, the United States, and Europe. In addition, the growth stage of the market is in the early stages of maturity, and patent applications for related technologies are expected to continue. In the future, based on the patent application trend analyzed in this study, the development direction of the automated concrete pouring system will be reviewed and the redundancy of similar technologies will be reviewed.

• Design & Manufacturing
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• v.17 no.2
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• pp.1-8
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• 2023

This study aims to enhance the price and quality competitiveness of imported tiles by developing a robotic tile production automation line. The development process involved several steps, such as requirement analysis, derivation of technical specifications, conceptual design, engineering feasibility review, detailed design, and production. Emphasis was placed on the transfer process of the tiles' molds, and technological advancements were achieved through engineering interpretation, feasibility review, and performance evaluation. The developed automation system incorporates key specifications to ensure a transfer success rate of over 90%, thereby ensuring stable transportation of the tiles and minimizing defect rates during production. The maximum weight capacity for tile pick-up was set above 6 kg, allowing effective handling of tiles weighing 6 kg or less in automated tasks. Furthermore, the system enables safe and precise movement of the tiles to the desired location, with a transfer distance of at least 1.3 m and a transfer speed exceeding 0.2 m/sec, thereby increasing production efficiency.

• Design & Manufacturing
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• v.18 no.2
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• pp.35-40
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• 2024

Injection molding is a process widely used across various industries for molding plastics, and it is the most commonly applied process in root industries utilizing molds. Among the different types of injection molding, insert injection molding, where busbars are used as inserts, is increasingly being applied in the electric vehicle industry. However, currently, the insert injection molding process is manually performed, with workers placing insert components by hand before injection molding. This results in issues related to productivity, safety, and quality. Additionally, there is a growing demand for automation of such production lines due to hazardous working conditions, economic difficulties in the manufacturing industry, and the decline in the labor force caused by an aging population. This study focuses on the application of an automated system for the insert injection molding process used in electric vehicles. The development of an automated system for the transport and insertion of insert components, as well as the inspection and stacking processes after injection, has resulted in over a 25% improvement in productivity and more than a 27% reduction in defect rates.

• International Journal of Contents
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• v.11 no.4
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• pp.70-76
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• 2015

The development of technology provides and increases security as well as convenience for humans. The development of new technology directly affects the standard of life thanks to smart home automatic control systems. This paper describes a door control, automatic curtain, home security (CCTV, fire, gas, safe, etc.), home control (energy, light, ventilation, etc.) and web-based smart home automatic controller. It also describes the use of ARM (Advanced RISC Machines) for automatic control of home equipment, a Multi-Axes Servo Controller using FPGA (Field Programmable Gate Array) and PLC (programmable logic controller). Additionally, it describes the development of a HTML editor using web auto control software. The tab loading time (7 seconds) is faster when using ARM-based web browser software instead of Chrome and Firefox is used because the browser has a small memory footprint (300M). This system is realized by web auto controller language which controls and uses PLCs that are easier than existing devices. This smart home automatic control technology can control smart home equipment anywhere and anytime and provides a remote interface through mobile equipment.

• KIEE International Transactions on Power Engineering
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• v.4A no.1
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• pp.42-47
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• 2004

This paper presents the various application programs for the Distribution Automation System (DAS) of the Korea Electric Power Corporation (KEPCO)'s distribution system. These programs are developed to allow for optimal operation in the areas of feeder automation, relay coordination, loss minimization and so on. They are single line diagram auto creation programs for the feeder, service restoration program, protection coordination program, data error detection program, and optimal network reconfiguration program. The details of these programs are presented for validity and effectiveness.

• Proceedings of the KIEE Conference
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• 2006.07a
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• pp.62-64
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• 2006

With the advent of the international standard IEC 61850 for communication networks and systems in substations, utilities are beginning to implement substation automation systems (SAS) that can give support to interoperability, interchangeability and self-description features. This paper describes with the SAS design accordance with this new standard. After a brief introduction of IEC 61850 SCL, this paper addresses some issues related to the specification of an IEC 61850 based SAS, and describes the Substation Configuration Language (SCL) based on Extensible Markup Language (XML). The SAS design process is explored with examples including the Intelligent Electronic Device (IED) selection, Logical Nodes (LN) allocation and the related services and the SAS communication architecture.