• Journal of the Korean Society of Marine Environment & Safety
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• v.24 no.4
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• pp.475-481
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• 2018

In this study, the safety and effectiveness of ope cutter, developed to prevent frequent accident propeller windingness at sea. First, we calculated the bolt strength of the three types of rope cutting devices used in the experiment and the torsional stresses on the shafting system theoretical equation and the finite element method. As a result, the bolts used in the rope cutter confirmed from the viewpoint of safety life design and fail safe design. Also, safety satisfactory because of the small effect on the shaft system when locking up. Experiments were carried out to cut ropes and fishing nets from the sea using the ships equipped with three types of rope cutters verified to be safe. As a result, ropes of 20 to 50 mm in thickness were generally cut. It was found that the cutting efficiency of a rope cutter attached to shafting decreased when cutting thick ropes.

• Korean Journal of Veterinary Service
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• v.42 no.1
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• pp.25-30
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• 2019

The objective of this study was to assess the possibility of detecting Foot-and-Mouth Disease Virus (FMDV) from the herd-based oral fluids specimens collected by the cotton ropes from pig farms that were found as FMDV nonstructural protein (NSP) antibodies positive. The cotton ropes were applied to detect FMDV in the selected pig farms which NSP antibodies were continuously detected in 2016, including the one pig farm which FMDV antigen were detected at the specimens from the pigsty environment. As the result, FMDV antigen were not detected in the oral fluid specimens collected by the cotton ropes. Theoretically, to detect FMDV antigen from the pigs with NSP antibodies has very low possibility because FMDV antigen disappeared at the time when NSP antibodies were produced by FMDV. Therefore, in order to detect FMDV antigen from the oral fluids using the cotton rope, it would be more effective to be applied to target the FMDV infected pigs rather than the NSP antibodies positive pigs. The collected oral fluids using cotton rope could be useful test specimens to monitor high-density pig populations for FMDV infection. Then, oral fluids sampling using cotton rope will be used for the efficient FMDV surveillance to detect FMDV antigen.

• Proceedings of the KIEE Conference
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• 1997.07b
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• pp.564-567
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• 1997

Various ropes used at the industrial fields can be used to experiment analyze tension tester development and also as an educational experiment tool. There fore the purpose of this paper is about rope tension tester development satisfying both safety and educational terms.

• The Bulletin of The Korean Astronomical Society
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• v.33 no.2
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• pp.36.1-36.1
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• 2008

• Journal of the Korean GEO-environmental Society
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• v.21 no.12
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• pp.17-21
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• 2020

Over 60% of South Korea's land consists of mountainous topography, and recently, due to earthquakes, localized heavy rains and road development, the risks of rockfalls are getting higher. As of now, rockfall prevention facilities are being constructed in 70% of Korean roads cut slope and rockfall protections account for about 20% of them. Rockfall protection's supporting capacity is defined by combining performance of wire mesh, pillars and wire ropes. For the existing constructed rockfall protection, standards of pillars that can absorb 48~61 kJ amount of energy, wire ropes and wire mesh are presented in Guidelines for the installation and management of traffic safety facilities, Rockfall prevention facilities by Ministry of Land, Transport and Maritime Affairs (2008). However, each factor's correlation of absorption energy is not presented so it is uncertain. This study will conduct vertical drop test and identify adequacy of rockfall protection net of displacement quantity calculation factor which is delta and evaluate rockfall protection net's absorbable energy through standards of overseas performance evaluation criteria.

• Journal of The Korean Astronomical Society
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• v.50 no.2
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• pp.29-39
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• 2017

We investigate two abnormal CME-Storm pairs that occurred on 2014 September 10 - 12 and 2015 March 15 - 17, respectively. The first one was a moderate geomagnetic storm ($Dst_{min}{\sim}-75nT$) driven by the X1.6 high speed flare-associated CME ($1267km\;s^{-1}$) in AR 12158 (N14E02) near solar disk center. The other was a very intense geomagnetic storm ($Dst_{min}{\sim}-223nT$) caused by a CME with moderate speed ($719km\;s^{-1}$) and associated with a filament eruption accompanied by a weak flare (C9.1) in AR 12297 (S17W38). Both CMEs have large direction parameters facing the Earth and southward magnetic field orientation in their solar source region. In this study, we inspect the structure of Interplanetary Flux Ropes (IFRs) at the Earth estimated by using the torus fitting technique assuming self-similar expansion. As results, we find that the moderate storm on 2014 September 12 was caused by small-scale southward magnetic fields in the sheath region ahead of the IFR. The Earth traversed the portion of the IFR where only the northward fields are observed. Meanwhile, in case of the 2015 March 17 storm, our IFR analysis revealed that the Earth passed the very portion where only the southward magnetic fields are observed throughout the passage. The resultant southward magnetic field with long-duration is the main cause of the intense storm. We suggest that 3D magnetic field geometry of an IFR at the IFR-Earth encounter is important and the strength of a geomagnetic storm is strongly affected by the relative location of the Earth with respect to the IFR structure.

• Journal of the Korea institute for structural maintenance and inspection
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• v.22 no.1
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• pp.56-63
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• 2018

The present study examined the reversal cyclic flexural behavior of walls with jacket section approach for seismic strengthening through forming the boundary elements at both ends of the wall. The prestressed wire ropes were used for the lateral reinforcement to confine the boundary element of the wall. The main parameter investigated was the height of the jacket section for strengthening. The limit height of the strengthening jacket section was determined by comparing the moment distributions between the existing and strengthened walls. Test results showed that the examined jacket section approach was significantly effective in enhancing the flexural resistance of walls, indicating 46% higher stiffness at peak strength and 210% greater work damage indicator, compared with the flexural performance of the unstrengthened wall. The ductility of the strengthened walls was insignificantly affected by the height of the jacket section when the height is greater than twice the wall length. The flexural capacity of the strengthened walls was 22% higher than the predictions obtained using the equivalent stress block specified in ACI 318-14.

• Journal of the Korean Society of Fisheries and Ocean Technology
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• v.56 no.2
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• pp.83-93
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• 2020

In fisheries, the importance of designing efficient fish cages is being emphasized as aquaculture has become more production than capture fishing. Particularly, the gravity cage system is one of the popular fish cage system in Korea. Currently, gravity cages of various shapes and sizes are being widely designed and installed in offshore and inland seas. The cage is subject to external forces, such as currents and waves, and the shape of the structure and tension on the ropes changes according to these external forces. Thus, it is important to accurately calculate these dynamic behavior, including the external forces and tension on the structure during the design stage. In this study, three types of cage systems with an equal internal volume of 8000 ㎥ were analyzed using mass-spring models and their behavior was interpreted through simulations. These simulations were used to analyze the behavior and tension of the ropes in response to currents and waves to aid in the selection of individual cage sizes for a given total volume. The numerical calculation results indicate that depending on the flow rate, the most resistant system is System 1, which has eight strays, and System 2 and System 3 have 69.4% and 54.8% of the resistance of System 1. Further, total resistance increased as the number of cages increased for all flow rates.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.25 no.2
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• pp.119-127
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• 2012

A wire rope is comprised of several metal wires which are wound together like a helix and it can resist relatively large axial loads, as compared with bending and torsional loads. A shipbuilding crane for erection such as a floating crane, a gantry crane, and a crawler crane hoists up and down heavy blocks by using these wire ropes. Thus, it is necessary to find dynamic properties of a wire rope in order to safely lift the blocks using the crane. In this study, a formula for calculating the tension and torsional moment acting on wire ropes of the crane was derived based on the existing study, and then dynamic simulation of the crane was performed based on the formula. The result shows that the dynamic simulation can be applied to find the safe method for block erection of shipyards.

• Composites Research
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• v.28 no.6
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• pp.378-382
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• 2015

With increasing population density and high-rise expansion of buildings in recent years, elevators have become to play a pivotal role in our everyday lives as most people take an elevator several times even in a day. The elevator penetration and distribution rates in Korea have increased dramatically every year, and the emergence of skyscrapers leads to accelerating the development of elevator industry. Carbon-fiber-reinforced plastics (CFRPs) exhibit better mechanical and thermal properties than steel suitable for uses as elevator wire ropes. In this paper, in order to analyze the properties of CFRPs, the tensile strength of unidirectional (UD) CFRP wire ropes was characterized and finite element analysis was conducted for bending simulation. Simulation results were compared.