• Title/Summary/Keyword: Power system reinforcement

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Development of modernizing Old Small-Hydropower system with custom-built at Overseas (해외 노후 수력발전시스템 수용가 맞춤형 현대화 기술개발 및 실증)

  • Kim, Woonhak;Kang, Seokwon;Shin, Giseok
    • Journal of the Society of Disaster Information
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    • v.14 no.2
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    • pp.174-181
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    • 2018
  • Purpose: The purpose of this study is to develop and demonstrate the customized modernization technology of the old aged hydropower generation system in operation Method: The modernization design was carried out based on the daily, weekly, monthly, and yearly information of the power plant in operation at the site. Results: In this paper, a safety diagnosis of existing facilities located in the Philippiness was carried out in accordance with the Special Act on the Safety Management of Domestic Facilities, and a method for reinforcing the facilities was selected. Conclusion: The selection of wheel suitable for the local environment and the maintenance of the old facilities were designed by domestic repair/reinforcement technology.

A Fundamental Study on Shearing/Bonding Characteristics of Interface Between Rock Mass and Backfills in Mine Openings (폐광산 채움재와 암반 경계부의 전단 및 접합특성에 관한 기초 연구)

  • Kim, Byung-Ryeol;Lee, Hyeon-woo;Kim, Young-Jin;Cho, Kye-Hong;Choi, Sung-Oong
    • Tunnel and Underground Space
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    • v.31 no.6
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    • pp.623-646
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    • 2021
  • As the demand for electric power increases with acceleration of electrification at home and abroad, the needs for coal-fired electrical power plant are accordingly increased. However, these coal-fired electrical power plants induce also many environmental problems such as increase of air pollutants, increase of possibility of land contamination by reclamation of coal ash, even though these power plants have a good economical efficiency. In case of a by-product of coal-fired electrical power plants, only 70% of them are recycled and the remaining 30% of by-product are fully buried in surrounding ground. Consequently, this study deals with coal ash backfilling mechanism in abandoned mine openings for the purposes of increasing the coal ash recycling rate as well as securing the mine area stability. In order to analyze the backfill and ground reinforcement by interaction between rock mass and backfills, the copying samples of discontinuous surface with different roughnesses were produced for bond strength tests and direct shear tests. And statistical analysis was also conducted to decide the characteristics of bond and shear behavior with joint roughness and their curing day. Numerical simulations were also analyzed for examining the effect of interface behavior on ground stability.

Lifetime of Insoluble Anode for Cathodic Protection on Concrete Construction

  • Sohn, Kicheon;Chang, Hyunyoung;Kim, Youngsik
    • Corrosion Science and Technology
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    • v.4 no.2
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    • pp.56-59
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    • 2005
  • In rebar concrete structure, the corrosion of rebar can arise the deterioration of concrete structure and may affect the safety of the whole system. Recently, several methods for corrosion protection have been used and are more important for concrete structure using the sand including chloride ion. Among several protections, electrical cathodic protection has been expected to be one of the most useful methods in corrosion protection for reinforcement of concrete structures. The anode for cathodic protection needs high current density, high corrosion resistance and low overvoltage. To fill up the special qualities, the insoluble anodes were developed and these anodes were coated with metal oxide of $TiO_2$, $ZrO_2$, $RuO_2$, and $IrO_2$. Lifetime of these anodes can be one of the important factors affecting the lifetime of concrete structure in cathodic protection. In this work, several anodes were made by sol-gel method and thermal decomposition method and the lifetime of these anodes was evaluated by NACE international standard test method, TM 0294-94. Also, we did analyze the properties of coated metal oxides.

Electrical and Mechanical Strength Properties of Epoxy/Micro Silica and Alumina Composites for Power Equipment (전력기기용, 에폭시/마이크로 실리카 및 알루미나 복합제의 전기적·기계적 파괴 강도 특성)

  • Park, Joo-Eon;Park, Jae-Jun
    • Journal of the Korean Institute of Electrical and Electronic Material Engineers
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    • v.31 no.7
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    • pp.496-501
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    • 2018
  • In this study, we prepared 40, 45, 50, 55, 60, 65, and 70 wt% content composites filled in epoxy matrix for two micro silica and three micro alumina types for use as a GIS heavy electric machine. As a filler type of epoxy composite, micro silica composites showed excellent AC breakdown strength properties compared to micro alumina composites in the case of electrical properties of micro silica and alumina. The electrical breakdown properties of micro silica composites increased with increasing filler content, whereas those of micro alumina decreased with increasing filler content. In the case of mechanical properties, the micro silica composite showed improved tensile strength and flexural strength compared with the micro alumina composite. In addition, mechanical properties such as tensile strength and flexural strength of micro silica and alumina composites decreased with increasing filler content. This is probably because O-H groups are present on the surface of silica in the case of micro silica but are not present on the surface of alumina in the case of micro alumina.

Mitigation of Stray Current Interference from DC Electric Railroad(3) Stray Current Confinement Method (직류전기철도의 누설전류 간섭대책(3) 누설전류 포집시스템)

  • Ha, Yoon-Cheol;Bae, Jeong-Hyo;Ha, Tae-Hyun;Lee, Hyun-Goo;Kim, Dae-Kyeong
    • Proceedings of the KIEE Conference
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    • 2005.10c
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    • pp.276-278
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    • 2005
  • For over 25 years, the stray currents from DC electric railroads have caused serious interference problems with underground metallic infrastructures in Korea. The most serious interference is reported at the pipelines near the depot areas. Our field survey proves that this phenomena is mainly due to the missing of dedicated rectifiers for mainline, depot and/or workshop areas. Because it takes so much time and costs too much to replace the traction power system, we consider a stray current confinement method which collects the stray currents and drains them to the negative terminal of the rectifier. This can be realized by installing a stray current collecting wire along the depot boundary. Moreover, we found the stray current collecting reinforcement bar located beneath the rails of concrete slab tracks. Using this bar, we arc going to draing the stray currents from mainline rails. In this paper we show the result of field survey on railroad facilities and present the stray current confinement method under field test.

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A Study on the Priority and Evaluation Criteria of Domestic Support Measures according to FTA (FTA 체결에 따른 국내지원대책의 평가기준 및 우선순위 선정)

  • Son, Yong-Jung
    • International Commerce and Information Review
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    • v.14 no.1
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    • pp.301-314
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    • 2012
  • To improve support for damages due to FTA and competitive power to overcome it, direct damages to farming and fisheries are compensated through Direct Payment Policy and Business Cessation Support System. Support plans will be developed to enhance competitive power in industries and income base in rural areas. This study carried an AHP to decide Priority and Evaluation Criteria in respect to domestic support measures according to FTA. For the AHP, the classes were categorized into direct damage conservation, higher competitive power and expansion of income. For the direct damage preservation measures, the classes were categorized into farmers, fishermen, manufactures, service business managers, and workers. In respect to reinforcement of competitive power of each industry, the classes were categorized into farming, fisheries, manufacturing, the drug industry, and service business. In respect to expansion of income, the classes were categorized into farming and fishing. Then 27 national support measures were presented for sub-classes. As a result of the analysis, it was discovered that more weight was given to measures to reinforce competitive power of each industry and expand income than those on direct damage conservation. In respect to higher competitive power in industries, more weight was given to support for farming and manufacturing. In respect to expansion of income, more weight was given on measures on farming than fisheries. For the direct damage preservation measures, more weight was given on support measures on farmers and workers.

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A Study on the Reinforcement of Logistics Competitive Power of Chonbuk Firms under the Circumstance of EC (EC환경하의 전북기업 물류경쟁력 제고방안)

  • Kim, Chang-Gyun
    • International Commerce and Information Review
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    • v.1 no.2
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    • pp.1-24
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    • 1999
  • In this study, I have suggested a basic theories in introducing and applying EC indispensible for a positive development of international logistics' competitiveness by the Chonbuk firms, and I assure that the Chonbuk firms can get a full effect in strengthening international competitiveness in worldwide trade war by effectively utilizing the application method suggested in this study as well as by erecting its basic direction. Our market faced an accelerating pressure against a full-scale market opening with the WTO system, and our Chonbuk firms will face a danger that all the markets, domestic and international will be occupied by the foreign enterprises, for we can not win the competition with the foreign enterprises, provided that we do not prepare for the rationalization and effectiveness of management. It will be very significant for our Chonbuk firms to introduce and utilize EC as a method for innovation and rationalization of management as well as a method for strengthening international competitiveness. This study will serve the study of this field, for the purpose of this study is on analyzing its propriety in introducing and utilizing EC. It will guarantee the importance that this study helps the Chonbuk firms to upgrade understanding on introduction and utilization of EC for strengthening their logistics competitiveness, and this study serves to improve international competitiveness in an era of information and globalization.

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A Study on the Historical Transformation of Guanyu' Deification from Political Perspective (정치적 관점에서 본 관우(關羽) 신격화(神格化)의 역사적(歷史的) 변모 양상 고찰)

  • Bae, Kuy-Beom;Min, Kwan-Dong
    • Cross-Cultural Studies
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    • v.42
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    • pp.313-342
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    • 2016
  • This paper is an attempt to look up the life of Guanyu who was a sainted warrior of Shu Han(蜀漢) and later, was revered as God, especially focusing on the Political perspective of Chinese Dynasty. People represented Guanyu as the general during the Wei Jin Southern and Northern Dynasties(魏晉南北朝), however, throughout the Su-Dang Dynasty(隋唐), Guanyu was Honored in the Wuchengwangmiao(武成王廟) then, was promoted from Hou(侯) to Gong(公), Gong(公) to King(王) in the Song-Yuan Dynasty(宋元). In the Ming-Qing Dynasty(明 淸) when the deification of Guanyu was proceeded most positively, he became a Di(帝) over a King and was endowed with the power over the Three Worlds(三界). He had an influence on nobility as well as the people in Folkbelief over Moral Spirits, and consequently rose through the ranks to become the spiritual guardian. The rulers gave him various names(封號) celebrating the life and work of Guanyu, In fact, they showed interests in the Belief of Guanyu as they attempted to establish an ideological base for the solution of the national disaster and maintenance of feudal system which came to the fore along with the reinforcement for emperor's power.

Stiffness Improvement of Timing Belt in Power Transmission (동력전달용 타이밍벨트의 강성 개선)

  • Lee, Kyeong-Yeon;Byun, Kyung-Seok
    • Journal of the Institute of Convergence Signal Processing
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    • v.23 no.1
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    • pp.1-7
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    • 2022
  • As a power transmission element, the timing belt is a toothed transmission belt that takes advantages of V-belts and gears. It has characteristics of non-slip and low noise. It is used as a power transmission device when transmitting power from a rotating shaft or linear motion in a mechanism. Rotation can be accurately transmitted through a belt pulley with grooves like a gear and a timing belt with grooves to precisely match with the belt pulley. In particular, in the mechanism in which the timing belt is used for the output shaft, the dynamic characteristics including the rigidity of the timing belt determine the transmission characteristics of the system, so its importance increases. In this paper, a stiffness reinforced belt that can be applied to a timing belt with a limited range of motion to increase its stiffness is proposed. To study the dynamic characteristics of the stiffness reinforced belt, the equation of motion for the stiffness reinforced belt was established, and a simulation model for the stiffness reinforced belt was created and analyzed. In order to confirm the analysis results of the motion equation and simulation model, a 1-axis rotation experimental equipment using a stiffness reinforcing belt was developed and the experiment was conducted. Through motion equations, simulation models, and experiment results, it was confirmed that the stiffness and dynamic characteristics of the timing belt could be improved by applying the proposed stiffness reinforcement belt.

A study on the model of regional balanced development for promoting small and medium sized enterprise (중소기업육성을 위한 지역균형발전 모형 연구)

  • Chang, Seog-Ju;Park, Roh-Gook;Yoon, Byung-Seop
    • Asia-Pacific Journal of Business Venturing and Entrepreneurship
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    • v.2 no.1
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    • pp.133-151
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    • 2007
  • In the era of 21st new century. reinforcement of regional competitiveness by establishing innovation system is taking its place of main small and medium sized enterprise policies in major developed countries. The model of regional balanced development for promoting small and medium sized enterprise is a main frame of governmental small and medium sized enterprise policies. which complements national innovation process. And in the level of local area, the model is regional network system, molded in the process of induction, application, modification, proliferation of new technologies and knowledge by local businessman and innovators. This study focused on the strategy development for small and medium sized businesses to increase local competitive power, in terms of regional balanced development. In order to find the real problems and improvement alternatives for local competitive power, this study both reviewed the common strategies and action programs advanced in developed countries for small businesses, and did research on the current economic conditions in local area. Based on the lessons from foreign cases and the analysis of the current situations in small business in local area, the study suggested the model of regional balanced development for promoting small and medium sized enterprise including formation of innovation network system through the invitation of leading firms in the area, industry-university partnerships, and development and attraction for small and medium sized businesses.

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