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A Study on Monitoring of Mitigation of Rail Corrosion using Sacrificial Anode Cathodic Protection Method (희생양극법을 적용한 철도 레일의 방식효과 모니터링 연구)

  • Choi, Jung-Youl;Park, Jong-Yoon;Lee, Kyu-Yong;Chung, Jee-Seung
    • The Journal of the Convergence on Culture Technology
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    • v.5 no.4
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    • pp.367-371
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    • 2019
  • In this study, we proposed the sacrificial anode cathodic protection method as a countermeasure to reduce the corrosion of railway rails under oceanic climatic conditions and proved the anticorrosive effect experimentally. In addition, the proposed sacrificial anode cathodic protection method were tested on site to examine long-term rail corrosion monitoring and field applicability for more than 26 months and to prove the effectiveness of rail corrosion. As a result of monitoring the corrosion state using the cellophane tape method, the appearance of the applied sections with sacrificial anode cathodic protection method was good at the present time about 26 months after the field test laying, and no abnormalities and other abnormalities of the rail welded section and the rail web were found. Hence, in places where no sacrificial anodes were installed, rust progressed rapidly. In addition, the proper spacing of sacrificial anodes was found to form the most stable corrosion coating at 1.0 ~ 1.5m. After about 26 months of monitoring, the installation of sacrificial anodes could help stabilize the overall rail corrosion level, even if the spacing was somewhat wider.

Analysis on Barriers and Resolution Priority of Sea-Rail Multimodal Logistics among Korea and Eurasia Nations (한국-유라시아간 해륙복합운송 문제점 및 해결 우선순위 분석)

  • Lee, Eon-Kyung;Lee, Suyoung;Kim, Bokyung;Euh, Seungseob
    • Journal of Korea Port Economic Association
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    • v.35 no.2
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    • pp.109-126
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    • 2019
  • The Panmunjom Declaration adopted by the leaders of South and North Korea on April 27, 2018, has created an environment conducive for peace and cooperation in the Korean Peninsula. In the June of last year, South Korea has joined the Organization for Cooperation between Railways (OSJD). The membership of OSJD has established a solid foundation for restoring a multimodal logistics system that connects the Korean peninsula to Eurasia countries, including China and Russia. In this paper, a questionnaire survey targeting working-level experts was conducted to find the barriers in constructing multimodal logistics that efficiently connect the port-continental railways of the Korean peninsula and the Eurasian nations. Survey items were divided into five categories-border crossing procedures, technology, facilities, operation, and government support. As a result, among the most important problems of international multimodal logistics in Eurasia that need to be solved on priority include improving transshipment facilities, eliminating inspection carried out at every country for transit, simplifying documents for customs clearance, and minimizing the changes in freight rates. In conclusion, for vitalizing the connection between the Korean peninsula and the continental railways, it is necessary to develop a transshipment system to facilitate the changes in tracks at the borders by making a joint effort with the international community. Second, railway and operational systems in South Korea, North Korea, China, and Russia should be standardized. Third, international cooperation among South Korea, North Korea, China, and Russia is essential for simplifying customs clearance at borders, priority departure of domestic cargo, sharing information about the changes in freight rates, and so on. Finally, the government should come up with measures to secure the quantity of cargo required to form block trains, while developing new business models.

Study on The Modification of The Transition Curve to Increase Operating Speed of Existing Line (기존선 속도 향상을 위한 완화곡선 변경 방안 연구)

  • Kim, Jae-Bok
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.20 no.10
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    • pp.26-32
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    • 2019
  • The purpose of this study is to improve the running speed on a small-radius curved section on an existing train line. When the transition curve was extended, and the amount of movement in the horizontal direction tended to increase as the curve radius increased. The amount of increase in the transition curve extension was lowest when extending the curve radius, and the amount of horizontal movement was the lowest when changing the curve radius to a cosinusoidal curve. As a result of applying the pass rate after improvement to the Kyeongbu line, there was a time-shortening effect of 9.4 to 11.6% and a facial expression speed increasing effect when the curve radius was fixed and the transition curve was changed to a sinusoidal curve. In conclusion, the most effective way to improve the running speed on an existing train route is to change the image to concrete and to change the relaxation curve to a cosinusoidal curve. The amount of horizontal movement of the track is small, and the speed improvement effect is excellent.

Evaluation of Shallow Foundation Behavior on Basalt Rock Layers With Clinker and Sediment Layers Reinforced Using Cement Grouting (현무암층 사이에 존재하는 클링커층과 퇴적층의 시멘트 그라우팅 보강에 따른 얕은 기초 거동 평가)

  • Lee, Kicheol;Shin, Hyunkang;Jung, Hyuksang;Kim, Donghoon;Ryu, Yongsun;Kim, Dongwook
    • Journal of the Korean Geosynthetics Society
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    • v.18 no.3
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    • pp.33-44
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    • 2019
  • Clinker layer is a stratum structure distributed in volcanic area such as Jeju Island. The clinker layers were formed in between the repetitive action of eruption and solidification of lava flows. Since the clinker layer contains a large amount of voids accompanied by the lava gas ejection process, there is a possibility of inducing overall stability of the ground due to the low stiffness and strength of the clinker layer. Therefore, in this study, site investigation was carried out at both ends of the 00 bridge where the clinker layers exist. And, based on the ground survey results, the behavior of shallow foundations was analyzed numerically. In addition, the improved shallow foundation behavior in grouting substitution using the chemical injection method of the clinker layer was compared with the shallow foundation behavior in the ground, and the grouting substitution efficiency of each layer was analyzed. As a result, the bearing capacity, the replacement efficiency and elastic settlement were different according to the presence or absence of the sediment layer. This is because the sediment layer has a lower stiffness and density than the clinker layer.

Dynamic Characteristics of Railway Structures under High-Speed Train Loading (고속열차 주행 시 동적하중을 받는 철도구조물의 진동 특성)

  • Rhee, Inkyu;Kim, Jae Min
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.33 no.2
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    • pp.121-128
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    • 2020
  • The purpose of this study is to investigate the distribution patterns of displacement and acceleration fields in a nonlinear soil ground based on the interaction of high-speed train, wheel, rail, and ground. For this purpose, a high-speed train in motion was modeled as the actual wheel, and the vertical contact of wheel and rail and the lateral contact, caused by meandering motion, were simulated; this simulation was based on the moving mass analysis. The soil ground part was given the nonlinear behavior of the upper ground part by using the modified the Drucker-Prager model, and the changes in displacement and acceleration were compared with the behavior of the elastic and inelastic grounds. Using this analysis, the displacement and acceleration ranges close to the actual ground behavior were addressed. Additionally, the von-Mises stress and equivalent plastic strain at the ground were examined. Further, the equivalent plastic and total volumetric strains at each failure surface were examined. The variation in stresses, such as vertical stress, transverse pressure, and longitudinal restraint pressure of wheel-rail contact, with the time history was investigated using moving mass. In the case of nonlinear ground model, the displacement difference obtained based on the train travel is not large when compared to that of the elastic ground model, while the acceleration is caused to generate a large decrease.

Fundamental study on enlargement method of existing subway tunnel during operation for sidetrack construction (부본선 건설을 위한 기존 지하철 터널의 운영 중 확폭 방안에 대한 기초연구)

  • Lee, Hyobum;Koh, Sung-Yil;Jun, Jonghun;Yoon, Hee Taek;Yi, Na Hyun;Choi, Hangseok
    • Journal of Korean Tunnelling and Underground Space Association
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    • v.22 no.1
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    • pp.59-76
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    • 2020
  • As a continuous increase in demand for the transportation infrastructure in the metropolitan area, the renovation of existing metropolitan and urban railway lines for the rapid transport system requires the construction of sidetrack that can operate local and express trains simultaneously. However, the construction of sidetrack after stopping the operation of the existing subway line causes a lot of economic losses, therefore it is essential to study the tunnel enlargement scheme during the operation of the existing subway tunnel. Accordingly, in this paper, basic research on the enlargement plan of the existing subway tunnel was carried out for the renovation of the existing subway line. In order to investigate the method for the sidetrack construction, the Government Complex Gwacheon station on the Gwacheon line of subway line 4 was selected as a virtual research station. Subsequently, four construction plans including tunnel cross-sectional plan for each section were reviewed and constructability and economic feasibility were compared. Finally, the stability assessment was conducted for the selected construction plan which was considered to be relatively unstable by 3-D full numerical analysis considering the sidetrack construction process.

Experimental analysis of heat exchanger performance produced by laser 3D printing technique (레이저 3D 프린팅 기법으로 제작한 열교환기 성능시험 분석 연구)

  • Kim, Moosun
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.7
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    • pp.270-276
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    • 2020
  • 3D printing is an additive manufacturing technology that can produce complex shapes in a single process for a range of materials, such as polymers, ceramics, and metals. Recent 3D printing technology has developed to a level that enables the mass-production through an improvement of the printing speed and the continuous development of applicable materials. In this study, 3D printing technology using a laser was applied to manufacture a heat exchanger for an air compressor in a railway vehicle. First, the optimal design of the heat exchanger was carried out by focusing on weight reduction and compactness as a shape suitable for 3D printing. Based on the design derived, heat exchanger prototypes were made of AlSi10Mg alloy material by applying the SLM technique. Moreover, the manufactured prototypes were attached to an existing air compressor, and the heat exchange performance of the compressed air was tested. The test results of the 3D printed prototypes showed a heat exchange performance of approximately 80% and 85% at low and high-pressure, respectively, compared to the existing heat exchanger. From the 𝓔-NTU method results with an external cooling air condition similar to that of the existing heat exchanger, the calculated heat transfer amount of 3D printed parts showed similar performance compared to the existing heat exchanger. As a result, the 3D printed heat exchanger is lightweight with good performance.

Feed System Modeling of Railroad using Fuel Cell Power Generation System (연료전지 발전시스템을 이용한 철도급전계통 모델링)

  • Yoon, Yongho
    • The Journal of the Institute of Internet, Broadcasting and Communication
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    • v.20 no.4
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    • pp.195-200
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    • 2020
  • With the growing interest in fossil fuel depletion and environmental pollution, railroad cars operating in Korea are in progress as the conversion from diesel to electric vehicles expands. The photovoltaic system, which is applied as an example of the conversion of electric vehicles, is infinite and pollution-free, and can produce energy without generating hazards such as air pollution, noise, heat, and vibration, and maintain fuel transportation and power generation facilities. There is an advantage that is rarely needed. However, the amount of electricity produced depends on the amount of solar radiation by region, and the energy density is low due to the power generation of about 25㎡/ kWp, so a large installation area is required and the installation place has limited problems. In view of these problems, many studies have been applied to fuel cells in the railway field. In particular, the plan to link the fuel cell power generation system railroad power supply system must be linked to the power supply system that supplies power to the railroad, unlike solar and wind power. Therefore, it has a close relationship with railroad cars and the linkage method can vary greatly depending on the system topology. Therefore, in this paper, we study the validity through simulation modeling related to linkage analysis according to system topology.

A Evaluation of Emergency Braking Performance for Electro Mechanical Brake using Interior Permanent Magnet Synchronous Motor (매입형 영구자석 동기전동기를 적용한 전기기계식 제동장치의 비상제동 성능평가)

  • Baek, Seung-Koo;Oh, Hyuck-Keun;Park, Joon-Hyuk;Kim, Seog-Won;Kim, Sang-soo
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.6
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    • pp.170-177
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    • 2020
  • This study examined the clamping force control method and the braking performance test results of an electromechanical brake (EMB) using braking test equipment. Most of the studies related to EMBs have been carried out in the automotive field, dealing mainly with the static test results for various control methods. On the other hand, this study performed a dynamic performance evaluation. The three-phase interior permanent magnet synchronous motor (IPMSM) was applied to drive the actuator of the EMB, and the analysis was verified by JMAG(Ver. 18.0), which is finite element method (FEM) software. The current control, speed control, and position control were used for clamping force control of the EMB, and the maximum torque per ampere (MTPA) control was applied to the current controller for efficient control. The EMB's emergency braking deceleration performance was tested in the same way as conventional pneumatic brake systems when the wheel of a train rotates at 110 km/h, 230 km/h, and 300 km/h. The emergency braking time, with the wheel stopped completely at the maximum rotational speed, was approximately 73 seconds. The similarity of the braking time and deceleration pattern was verified through a comparison with the performance test results of the pneumatic brake system applied to the next generation high-speed railway vehicle (HEMU-430X).

A Study on the Process of Pacific Park Development in NYC -Focusing on the Changes & Responds Shown in the Development Process- (뉴욕시 퍼시픽 파크 개발의 진행과정에 대한 분석적 고찰 -개발 진행상의 변화 및 위기대응과정을 중심으로-)

  • Lee, Woo Hyoung
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.21 no.1
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    • pp.745-752
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    • 2020
  • The purpose of this study is to analyze the development progress of Pacific Park (formerly Atlantic Yard) in Brooklyn, New York City. Along with the Hudson Yards Development in Manhattan, Pacific Park is one of New York City's leading large-scale urban development projects using space right above an existing railway and has attracted worldwide attention. With the resurgence of large-scale development, its advanced form has received social attention. In particular, the development was evaluated as an exemplary development using the Community Benefits Agreement, which benefits local residents. Unfortunately, due to various difficulties, the development has been struggling from delays and changes away from the early stages, which have also caused social concerns and criticism. In this regard, this study examines the development through the process and the public sector's responses to the risk-inducing factors and reactions. The theoretical background of the US urban redevelopment is examined, and the specific changes and major contents of the project are analyzed. The following implications were drawn based on changes and responses in the development process: 1) securing the flexibility and mandatoryness of developers, 2) comprehensive control of the development site, 3) communication with and responding to the public, 4) securing additional financial resources, and 5) verification of new technologies.